Caribbean - Central America Weather

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
454 AM AST Wed Oct 16 2024

.SYNOPSIS...

A dry airmass, with low concentrations of Saharan Dust will be
over the islands during the morning. An area of enhanced moisture
will then move in from the southeast into the vicinity of the
Virgin Islands and eastern Puerto Rico later in the afternoon. A
Heat Advisory will be in effect for most of northern PR, as well
as western, southwestern & south- central PR, from 10 AM to 4 PM.
The National Hurricane Center continues to monitor an area of low
pressure (Invest 94L) located in the Central Tropical Atlantic.
This disturbance has a medium (50%) formation chance through 7
days and could approach the area by Friday into Saturday. An
increase in shower and thunderstorm activity can be anticipated
starting on Friday. Therefore, an elevated risk of flooding, river
rises, and mudslides is expected.

&&

.SHORT TERM...Wednesday through Friday...

The night was fairly quiet across the local islands with lows
ranging from the mid-60s in the mountain, to the mid 70s and low
80s at coastal areas. The area has been under a pocket of dry air
that limited the development of showers last night. In general,
this pattern is expected to continue through the morning hours.
Then, in the afternoon, an area of enhanced moisture will move
from the southeast into the vicinity of the Virgin Islands and
eastern Puerto Rico, triggering some showers. In the afternoon,
additional showers and even isolated thunderstorms could fire up
from Mayaguez to Aguadilla.

The trade winds today and tomorrow will be from the east, with a
slight southeast component. These winds are driven by a high
pressure system centered over the eastern Atlantic. A ridge also
dominates the mid levels, thus conditions aloft will not be
particularly favorable for strong shower accumulation. There are
some small concentrations of Saharan dust too, so skies will look
hazy at times.

Temperatures will continue to be on the hot side too, with 925 mb
values over one standard deviation above the climatological mean.
Therefore, heat indices values that will potentially affect those
without effective cooling or adequate hydration will persist,
especially in low-elevated municipalities, urban areas, and
valleys.

Now on Friday, the attention is shifted toward Invest 94L, the
tropical wave with a medium chance of tropical cyclone formation
in the next 7 days. Although uncertainty still exist on how
organized the system will be as it approaches the Virgin Islands
and Puerto Rico, an increase in shower and thunderstorm activity
can be anticipated starting on Friday. Therefore, an elevated risk
of flooding, river rises, and mudslides is expected.

.LONG TERM...Saturday through Wednesday...

Model guidance indicates precipitable water (PWAT) values above 2
inches to start the weekend. This is due to Invest 94L, a well
defined area of low pressure over the central tropical Atlantic
that is being monitored by the NHC. Environmental conditions are
expected to become marginally conducive for gradual development by
the latter part of this week. This system currently has a 50
percent formation chance through 7 days. Model guidance has the
system near the local islands Friday into Saturday. Although there
is still uncertainty, an increase in overall moisture is forecast
even if the system doesn't develop, as it would still pass as a
tropical wave and it's broad moisture field would engulf the
region. With increased moisture and overall more unstable
conditions, the chance for overnight and afternoon showers and
thunderstorms on Saturday will increase along with the potential
for localized flooding impacts in urban areas, on roads, and along
some rivers and small streams across Puerto Rico and the U.S.
Virgin Islands. Columnar moisture above 2 inches will continue
through the end of the forecast period along with light to
moderate southeasterly winds. The weather pattern will include
overnight and early morning showers steered by this windflow along
parts of the east and south coastal sections of the islands with
afternoon convection expected but mainly focused across the
central interior and northern sections of Puerto Rico. High heat
indices will continue. For more information regarding Invest 94L,
please refer to the latest Tropical Weather Outlook (TWOAT &
TWOSAT) issued by the NHC.

&&

.AVIATION...

(06Z TAFS)

Mainly VFR conditions expected to prevail through the forecast
period. Small concentration of Saharan dust could lead to HZ in
the sky, but with VIS at P6SM. SHRA could increase after 21Z
across the USVI terminals, but with limited impacts to operations.
Additional activity is anticipated after 18Z, with some showers
reaching TJBQ, and brief periods of reduced VIS and low ceilings
possible. Winds will be from the ESE at 11-15 kts, with stronger
gusts.

&&

.MARINE...

Gentle to moderate easterly winds with a slight southeast component
will prevail today as a weak surface high pressure pattern
continues northeast of the region. Isolated to scattered showers
will move across the waters. Seas up to 4 to 5 feet are forecast
through tomorrow. The NHC is monitoring Invest 94L over the
central tropical Atlantic, which could increase winds and seas by
Friday. By early next week, swells from a low pressure over the
western Atlantic will also deteriorate marine conditions.

&&

.BEACH FORECAST...

There is a moderate risk of rip currents for Culebra and eastern
St. Croix today with a low risk elsewhere. Life- threatening rip
currents often occur in the vicinity of groins, jetties, reefs,
and piers.

&&

.CLIMATE...

Yesterday, the San Juan Area/PR station in the Luis Munoz Marin
International Airport registered a maximum temperature of 93°F.
The San Juan Area/PR station now has 37 consecutive days with
highs at 90°F or more, a new record. The previous record of 36
days was set in June and July 2012.

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
413 AM AST Thu Oct 17 2024

.SYNOPSIS...
A tropical wave, Invest 94L, will move north of the islands on
Friday and Saturday, bringing an increase in showers and
thunderstorms. A cold front and increasing moisture will combine
to bring even more showers and thunderstorms from the weekend into
next week. A northerly swell will arrive late in the weekend and
early next week, deteriorating marine and coastal conditions.

&&

.SHORT TERM...Today through Saturday...

Overnight shower activity stayed mostly over the waters under
easterly winds with some affecting inland areas of eastern Puerto
Rico, Vieques, Culebra and the USVI. Stations reported lows in the
upper 70s to lower 80s across lower elevations of the islands, and
in the upper 60s across higher elevations of Puerto Rico. Current
satellite derived precipitable water values, indicate a more humid
air patch with precipitable water (PWAT) values above 1.85 inches
approaching the region. A strong high pressure over the Atlantic
will steer this moisture patch towards our area. This patch is
currently nearing the Anegada Passage and is forecast to cross the
islands today, boosting moisture. This, along with sea breeze
convergence, diurnal heating, and local effects can help produce
afternoon shower and thunderstorm activity over western
municipalities. Trade wind showers will also continue to reach the
eastern region. A Heat Advisory will be in effect from 10 AM to 4
PM, for northern, western and southern municipalities of Puerto
Rico, and for the U.S. Virgin Islands. This is due to, heat indices
values reaching above 107 degrees. High Heat indices can potentially
affect those without effective cooling or adequate hydration,
especially in low-elevated municipalities, urban areas, and valleys.
Small concentrations of Saharan Dust will also be present. PWAT
values will increase again early on Friday to above 2 inches, as
Invest 94L, a tropical wave, approaches the islands. According to
the latest Tropical Weather Outlook, environmental conditions around
this disturbance appear only marginally conducive for slow
development as it quickly W to W-NW. The system currently has a low
formation chance through the next 7 days. This system will still
most likely approach our local islands tomorrow as a tropical wave,
increasing moisture and instability as well as increasing the
potential for showers and t-storms. An elevated risk of flooding,
river rises, and mudslides is expected. PWAT values above 2 inches
will continue through Saturday, promoting a wet pattern under east
to east-southeast winds.

.LONG TERM...Sunday through Thursday...
A cold front will dig just north of the Central Caribbean by
Sunday. This system will gradually make the winds shift from
south-southeast through Wednesday. Moisture will lift from the
Caribbean Sea, converging over the local islands. As a result,
showers and thunderstorms will increase in frequency, and could be
heavy at times. The risk of flooding will be elevated, with
potential for mudslides in areas of steep terrain, as well as
rapid river rises. The eastern and southern portions of Puerto
Rico, as well as the Virgin Islands are the areas with the highest
probability of precipitation. The days with the best potential for
rain are from Sunday to Tuesday. By Wednesday, conditions will
begin to dry out, but gradually. Moisture will linger at the
surface, so some showers are still anticipated. This break will
not last long, as more moisture is expected to reach the eastern
Caribbean by Thursday and Friday.

It should be noticed that if a dense cloud coverage develops, it
could work to lower the temperatures a little. However, if
sunshine peeks, and with a deep-layer south flow, it will feel
very muggy and steamy.

&&

.AVIATION...
(06Z TAFS)

Mainly VFR conditions across the terminals. E to ESE winds at 11 to
15 kts with sea breeze variations and higher gusts, decreasing and
with land breeze variations after 17/22Z. Brief MVFR conditions can
result from VCSH/VCTS starting over the interior that can affect
TJBQ around 17/17Z-22Z. Low concentrations of Saharan dust will
persist, visibilities will still be P6SM.

&&

.MARINE...
Surface high pressure over the eastern Atlantic will maintain a
moderate easterly wind flow across the area. Isolated to scattered
showers will move across the waters. The NHC is monitoring Invest
94L over the central tropical Atlantic, which could increase winds
and seas across the offshore Atlantic tomorrow. By early next week,
swells from a low pressure over the western Atlantic will also cause
marine conditions to deteriorate.

&&

.BEACH FORECAST...
A small northeasterly swell will increase the rip current risk to
moderate today for northern Puerto Rico, Culebra, Vieques, and
Saint Croix. The risk will stay moderate through early in the
weekend, but another, stronger swell, could increase it to high
early next week.

&&

.HYDROLOGY...
A wetter pattern is expected for the islands beginning Friday and
stretching into next week. First, moisture associated with Invest
94L will reach the islands on Friday and early Saturday. Then,
moisture from the tropics will combine with a cold front exiting
the eastern coast of the United States. As a result, periods of
showers will affect the local islands, increasing the risk of
flooding, river raises, and mudslides.

&&

.CLIMATE...
The streak of consecutive days above 90 degrees continue for the
Luis Munoz Marin International Airport. The forecast for today
again calls for a high of at least 90, making it the 39th day in a
row with at least 90 degrees. The average temperature of the year
so far (calculated from January 1st to October 15th) is 83.5F,
making it the warmest first 3/4 of a year on record.

Other COOP stations with impressive consecutive days above 90s
include Guayama 1SW, with 61 days, making it the 4th warmest
streak on record. This streak ended yesterday when a high of 89F
was reported. Magueyes Islands also had it second streak, with 79
days. This was back in July 4 through September 20.

[cycloneye]

National Weather Service San Juan PR
426 AM AST Fri Oct 18 2024

.SYNOPSIS...
A tropical wave, Invest 94L will move north of the area today and
tonight, increasing the potential for showers and thunderstorms.
Conditions will become more favorable for rainfall activity for
the weekend and next week, with an elevated risk of flooding
anticipated. A northerly swell will increase the risk of rip
currents to high for Monday.

&&

.SHORT TERM...Today through Sunday...

Overnight shower activity has gradually increased over the waters
under easterly winds. Some showers moved inland over areas that
include northeastern Puerto Rico (including sectors of the
metropolitan area), southeastern Puerto Rico, Vieques, and the USVI.
Stations reported minimum temperatures in the upper 70s to low 80s
across lower elevations of the islands, and in the upper 60s to low
70s across higher elevations of Puerto Rico. Current satellite
derived precipitable water (PWAT) values, indicate a contrast
between a drier patch with values around 1.10 to 1.30, over most of
Puerto Rico and its northwestern and western waters, and the
moisture field related to a tropical wave, Invest 94L, with values
above 2.00 inches, thats currently east of the U.S. Virgin Islands.
According to the latest tropical weather outlook: Invest 94L has a
low formation chance (10 percent) through the next 7 days. However,
it is still producing disorganized showers and thunderstorms east
and northeast of our local islands. The system will quickly move W
to WNW, passing near or just north of the area today, increasing
moisture and instability as well as increasing the potential for
showers and t-storms. An elevated risk of flooding, river rises, and
mudslides is forecast. The moisture field of above 2 inches, related
to this system will engulf most of the region today through this
evening. A lull in the wet period during the short and long term
will occur as a drier air patch moves across the area after Invest
94L during the overnight hours on Saturday. PWAT values will
increase again, to above 2.0 inches Saturday afternoon through
Sunday as both moisture reaches the area from the east and a frontal
boundary, with a pre-frontal trough, also digs to just north of the
Central Caribbean by Sunday. With elevated flooding risks during the
short term period, flooding of urban areas, roads, small streams and
are forecast with isolated flash flooding possible.

.LONG TERM...Monday through Friday...
A mid to upper trough will continue to escort a cold front just
to the northwest of the islands. At the surface, high pressure
over the eastern Atlantic will drive the trade winds from the
southeast on Monday. By Tuesday and Wednesday, another mid to
upper level trough will exit the eastern coast of the United
States, causing the winds to gain a more southerly direction from
the surface into the middle levels of the atmosphere. Under this
flow, moisture will move from the Caribbean Sea into the local
islands, increasing the potential for showers and thunderstorms.
The first pulse of moisture is anticipated for late Monday into
Tuesday, and there could be a break on Wednesday. By the end of
the week, however, additional areas of moisture will reach the
islands. With southerly winds, available moisture will combine
with local effects to trigger showers along the Cordillera
Central, then moving across northern Puerto Rico. Additional
activity is also expected in the local waters, reaching the Virgin
Islands, southern and eastern Puerto Rico at times too.

&&

.AVIATION...
(06Z TAFS)

E to ESE winds up to 11-15 kts with sea breeze variations and higher
gusts, decreasing and with land breeze variations after 18/22Z.
SHRA/TSRA over the waters, increasing after 18/09Z, can reach
JSJ/ISX/IST and promote MVFR conditions. MVFR conditions can also
result from VCSH/VCTS starting over the interior and moving towards,
and affecting, TJBQ (and possibly TJPS) around 18/17Z-22Z.

&&

.MARINE...
Invest 94L located east of the Leeward Islands will pass just north
of the region today. This will bring squally weather across the
local waters from through tonight, particularly across the Anegada
Passage and the Atlantic waters. By early next week, swells from a
low pressure over the western Atlantic will spread across the
Atlantic waters and passages.

&&

.BEACH FORECAST...
A small long-period northeasterly swell will contribute to a
moderate rip current risk along northern Puerto Rico, Culebra and
Saint Croix. This risk will persist through the weekend,
potentially increasing to high on Monday as another northerly
swell arrives.

&&

.HYDROLOGY...
Conditions will shift to the wet side starting today. First,
Invest 94L will bring increasing showers and thunderstorms across
the area. Then, for the weekend and next week, an approaching cold
front and moisture coming from the Caribbean Sea will combine to
generate additional periods of rain. This will increase the risk
of flooding, mudslides and rapid river raises.

&&

.CLIMATE...
The hot streak of consecutive days above 90 degrees could continue
today, unless enough showers and cloudiness prevent temperature
readings to reach this threshold. Regardless, 39 days of highs
above 90s have been recorded already at the Primary Climate Site,
located in the LMM International Airport.

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
403 AM AST Sat Oct 19 2024

.SYNOPSIS...

A patch of moisture will increase the potential for showers and
thunderstorms across Puerto Rico and the U.S. Virgin Islands
today. The strongest activity is forecast to develop along the
Cordillera Central, moving into northwestern Puerto Rico, and from
El Yunque into portions of the San Juan metro area. A series of
trough and a cold front will maintain unstable conditions until
mid week. Warm to hot temperatures will continue across the
islands for the next several days. A Heat Advisory will be in
effect today for all the coastal and urban areas of the islands.

&&

.SHORT TERM...Today through Monday...

The night was relatively quiet, with just a few showers reaching St.
Thomas, St. John, Vieques, Culebra and eastern Puerto Rico.
Elsewhere, the skies were free of clouds, allowing for temperatures
to cool down to the mid-70s to low 80s, and even below 70 in the
mountains. In the most recent satellite-derived precipitable water
imagery, the moisture field of Invest 94L can be appreciated just
north of the islands. Over Puerto Rico and the Virgin Islands, a dry
air mass dominates, but this will be replaced today with a small low
level patch of moisture currently approaching from the Leeward
Islands.

At the surface, the circulation of Invest 94L, and a branch of a
surface high pressure over the eastern Atlantic extending into the
eastern Caribbean, are promoting trade winds from the southeast at
10 to 15 mph. At the upper levels, high pressure holds north of the
western Caribbean, so dynamics today will not be particularly
favorable for strong shower development. However, with the upcoming
moisture, and very strong diurnal heating, showers are expected to
develop along the Cordillera Central, moving into northwestern
Puerto Rico, and from El Yunque into portions of the San Juan metro
area. The patch of moisture will also trigger showers over the
Virgin Islands and eastern Puerto Rico at times.

Sunday looks similar, but precipitable water values are expected to
climb above 2.0 inches. The frequency of showers will increase,
particularly for the vicinity of the Virgin Islands, and eastern
Puerto Rico. The activity in the west of Puerto Rico in the
afternoon hours could be stronger as well, leading to urban and
small stream flooding, and water surges along rivers.

Moving into Monday, a mid to upper level trough and its associated
cold front will aid in shifting the winds more from the southeast
from the surface into the mid levels of the atmosphere. This will
act to pull moisture from the Caribbean Sea into the area.

In terms of temperatures, with winds coming mostly from the
southeast, and with high humidity levels at the surface, the
scorching heat will not give way, and conditions will remain hot for
the upcoming days. The only relief from this heat spell would be if
enough clouds move in and disrupt the diurnal heating cycle.
Regardless, temperatures will remain well above the climatological
value beyond the forecast period, so stay hydrated and in the shade
when possible.

.LONG TERM...Tuesday trough Friday...

A mid to upper level trough is expected to exit the eastern coast
of the United Sates on Tuesday. This will result in a south-
southeasterly wind flow through at least Thursday. Therefore, an
increase in moisture pulled from the Caribbean waters is
anticipated. As the moisture field reaches the islands, the
potential for showers and thunderstorms will increase. The
expected activity could result in ponding of water in roads and
low drainage areas, urban and small stream flooding and quick
river risers mainly across the Cordillera Central towards western
Puerto Rico. The latest precipitable water guidances suggest from
1.75 to 2.00 inches for the first half of the period. However, the
second part of the period looks wetter with PWAT values of 1.90
to 2.13 inches. Overall, unstable and wet conditions will persist
through the next weekend. Conditions will slightly improve on
Saturday as drier air establishes over the region. Despite of the
rainfall activity, hot conditions are likely to continue with
elevated heat threat.


&&

.AVIATION...
(06Z TAFS)

Mainly VFR conditions expected to prevail. SHRA will increase in
frequency for the USVI and TJSJ terminals through the period. From
17-22Z, SHRA and isolated TSRA expected for TJBQ, where periods of
reduced VIS and low ceilings can be expected. Winds will increase
after 13Z, out of the ESE at 8-13 kts, with strong gusts and sea
breeze variations.


&&

.MARINE...

Showers and thunderstorms associated with a trough of low pressure (AL94)
located more than 100 miles north of Puerto Rico, will continue to affect
portions of the regional waters and local passages through the rest of
the weekend. By early next week, swells generated from the another area
of low pressure over the western Atlantic will spread across the Atlantic
waters and passages.

&&

.BEACH FORECAST...

There is a moderate rip current risk along northern Puerto Rico,
Culebra and the U.S. Virgin Islands. This risk will persist
through the weekend, potentially increasing to high on Sunday
night as another northerly swell arrives.

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
355 AM AST Sun Oct 20 2024

.SYNOPSIS...

Another hot day is expected across Puerto Rico and the U.S. Virgin
Islands. Today, the combination of local effects and daytime
heating will result in showers and thunderstorms, mainly over the
interior and western Puerto Rico. This weather pattern will
continue through Tuesday, when a drier airmass with a small area
of Saharan dust enters the region.

&&

.SHORT TERM...Today through Tuesday...

It was another warmer than normal night, with lows in the low 80s
for the eastern municipalities of Puerto Rico and the Virgin
Islands. Temperatures felt a little cooler for the mountain with
lows near 70 degrees. The frequency of showers increased across the
local waters, but rainfall accumulation was minimal. These showers
are associated with a patch of moisture currently approaching the
Virgin Islands. As the day heats up, the available moisture will
combine with local effects to trigger some showers in the interior
and northwestern Puerto Rico, with additional showers also
developing in the interior and from El Yunque into the San Juan
metro area. This will elevate the risk of flooding, as well as
ponding of water on roadways and low-lying areas.

The frequency of showers will increase early on Monday, as moisture
continues to being carried by the southeasterly wind flow. However,
in the afternoon and on Tuesday, the atmosphere will dry out as a
small area of Saharan dust arrives. Light to moderate concentrations
are expected, enough to turn skies hazy gray and to reduce
visibilities a little too. As it has been the story this whole
summer and fall, temperatures will remain well above normal, with
925 mb temperatures nearly two standard deviation above the
climatological mean. Therefore, excessive heat indices will persist
each day, and people should avoid strenuous activities outside,
particularly from 10 AM to 4 PM AST each day.

.LONG TERM...Wednesday into Saturday...

A mid to upper level trough will exit the eastern coast of the
United States from Tuesday into Wednesday, promoting south-
southeasterly wind flow throught the first half of the long term
period. This trough in combination with an exiting cold front will
result in unstable conditions across the islands. As the trough
moves well north of the region, a big moisture field will be
lifted from the Caribbean waters into the local area. The latest
precipitable water content analysis (PWAT) has values of 1.70
inches on Wednesday, increasing to 2.20 inches from Wednesday
afternoon into Thursday. Under this pattern there is an increased
potential to observe showers and thunderstorms, that may result in
an elevated risk for urban and small stream flooding, quick river
rises and mudslides across the region. By Thursday evening, winds
will start veering from the east as a strong tropical wave
approaches the islands from the east. Associated moisture with
values up to 2.30 inches, are expected to generate heavy rainfall
across Puerto Rico and the US Virgin Islands. This passing
tropical wave will also enhance the potential for flooding hazards
across the area. On Saturday, as the wave departs the region much
drier air will start to filter into the islands promoting more
stable weather conditions through the weekend.

&&

.AVIATION...
(06z)

Mainly VFR conditions expected, but SHRA will increase in
frequency across the Caribbean and Atlantic waters. This activity
could reach the USVI and TJSJ terminals at times. After 17Z, SHRA
and TSRA expected for TJBQ, with periods of reduced VIS and low
ceilings. Winds are from the ESE at 8-14 kts, with strongest gusts
and sea breeze variations.

&&

.MARINE...

A light to moderate east southeast wind flow will continue to
prevail across the local waters during the next several days. A
northerly swell will spread across the Atlantic waters and passages
tomorrow afternoon into Monday, gradually deteriorating marine
conditions particularly across offshore Atlantic Waters.

&&

.BEACH FORECAST...

There is a high rip current risk along the beaches from
northwestern to northeastern Puerto Rico and Culebra. Later today,
the islands of St. John and St. Thomas will be under the high
risk as well. There is a low to moderate risk of rip currents
elsewhere. For a more detailed forecast, please refer to the
Coastal Hazard Message (CFWSJU) and the Surf Zone Forecast
(SRFSJU).

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
543 AM AST Mon Oct 21 2024

.SYNOPSIS...Low pressure over the western Atlantic and high
pressure over the central Atlantic will cause east southeast to
southeast flow across the area. This will bring continued above
normal temperatures. Bands of moisture will bring periods of
showers and thunderstorms to the area through the next seven days.

&&

.SHORT TERM...Today through Wednesday...

Calm weather conditions prevailed overnight across the region, with
isolated showers over the Caribbean waters and the Mona Passage.
However, very few passing showers moved inland over the U.S. Virgin
Islands and eastern Puerto Rico. Another warmer than normal night
was observed in the islands, with lows in the lower 80s across
the coastal and urban areas, and in the 70s along the Cordillera
Central.

A gradual increase in showers is expected this morning as a surge of
tropical moisture carried by southeasterly winds moves into the local
area. As the day progresses, the combination of daytime heating,
local effects and the available moisture will trigger afternoon
convective activity across the interior and northwestern Puerto
Rico. Showers and thunderstorms across these sectors could lead to
urban and small stream flooding, and quick river rises. In addition,
showers will develop during the afternoon hours from El Yunque into
the San Juan metropolitan area and adjacent municipalities. Some of
the risks across these sectors include the potential for ponding of
water in low drainage areas and roads. Latest model guidances
continues to suggest the entrance of a drier airmass with light to
moderate concentrations of Saharan dust on Tuesday morning. However,
despite of the presence of drier air, an active afternoon is
expected for northwest Puerto Rico with showers and isolated
thunderstorms. By Tuesday night into Wednesday, an increase in
moisture is anticipated, once again. Precipitable water values are in
the range of 1.9 to 2.3 inches enhancing the potential for
additional shower activity across the region.

Warm to hot temperatures will continue due to abundant tropical
moisture, southeasterly wind flow, and well above normal 925 mb
temperatures. Excessive heat indices will persist for the next
several days across Puerto Rico and the U.S. Virgin Islands.
Residents and visitor are encouraged to take extra precautions when
outside. Drink plenty of fluids and void strenuous activities
outside, particularly from 10 AM to 4 PM AST each day.

.LONG TERM...Thursday through Monday...

The low pressure over the western Atlantic will move north
northeast on Thursday and Friday and an associated cold front will
approach the local area. This will pull moist air from the south
out of the Caribbean. A pre-frontal band will form on Thursday
ahead of the front to our east and move over the area later
Saturday and Sunday brining more showers and thunderstorms to the
area. Drying is expected on Monday. At mid levels the 500 mb high
will prevail over the area. At upper levels a ridge will prevail
during the long term period. This will fight the instability
needed to bring a more active weather situation, but still allow
for showers and thunderstorms to form during the wet intervals
supplied by the bands of moisture formed from convergence ahead of
the front and passing waves in the easterly trade winds.

&&

.AVIATION...
(06Z TAFs)

Mainly VFR conds expected to prevail across all TAF sites through
the forecast period. Tradewind showers will result in VCSH at
TJSJ/TIST/TISX thru 21/14Z. An increase in moisture will result in
afternoon SHRA/TSRA that may result in brief MVFR conds at
TJSJ/TJPS/TJBQ aft 21/17-18Z. Mtn tops obscd and low cigs
expected along the Cordillera Central thru 21/22Z. Winds are from
the ESE at 9-14 kts with higher gusts and sea breeze variations.

&&

.MARINE...

Seas at the outer buoy (41043) have subsided to around 6
feet, although a few pulses may still move through. The inner
buoy on the north coast where much of the wave action is
occurring, has been rising, but appears to have peaked at 6 feet
and 11-12 seconds. Therefore have taken down the high surf
advisory. Nevertheless a high rip current risk will remain across
the northern coasts of Puerto Rico and the U.S. Virgin Islands.


&&

.BEACH FORECAST...

With the diminishing waves, have taken down the high surf
advisory. Nevertheless a high rip current risk will remain across
the northern coasts of Puerto Rico and the U.S. Virgin Islands
through this evening.

&&

.CLIMATE...

Yesterday was close to breaking record highs and lows, but could
not. However the average temperature did tie the warmest October
20 on record at 87.5 degrees. This average was previously reached
in 2016.

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
437 AM AST Tue Oct 22 2024

.SYNOPSIS...Warm weather persists mostly due to southeasterly
flow. An area of drier air is moving into the area, but will soon
be followed by another area of moisture Wednesday. A gradual
cooling trend is expected after Wednesday that should continue as
a cold front approaches from the northwest Tuesday and Wednesday
of next week.

&&

.SHORT TERM...Today through Thursday...

Showers and thunderstorms were observed during the overnight hours,
mostly over the local Caribbean and Atlantic waters. However, some
of this activity reached the southern and southeastern portions of
Puerto Rico, and the U.S. Virgin Islands. Doppler radar estimated
rainfall accumulations of less than 0.5 inches across these areas.
Overall, warm conditions were seen across the region with lows in
the low 80s along the coastal and urban areas of the islands, and
from the low to mid 70s in the higher elevations. This activity is
expected to continue through the morning.

Relatively drier air will move into the area today accompanied by
light to moderate concentrations of Saharan dust particles. Despite
of the drier air filtering into the region, showers and
thunderstorms are anticipated, once again, across the interior and
northwestern portions of Puerto Rico due to the combination of daytime
warming and local effects. By tonight into Wednesday, tropical
moisture will return as a broad moisture field associated with a
tropical wave approaches the area from the east. Precipitable
water values of approximately 2.0 inches will remain across the
area for the rest of the forecast period. Therefore, there is the
potential to observe showers and thunderstorm activity across the
interior, northwestern PR and the San Juan metro area each day. By
Thursday a low pressure located over the western Atlantic will
move north of the region. The associated cold front is forecast to
deepen approach the islands by Thursday night. A prefrontal
trough will enhance the potential for another round of convective
activity. With the expected rains, there is the potential to
observe minor flooding in urban areas and small streams and quick
river rises.

Temperatures will continue to rise over the next few days in the
islands. For today, highs may reach the low to mid 90s along the
coastal and urban areas. Therefore, San Juan could register our 44th
consecutive days with temperatures 90 or more degrees Fahrenheit.
Residents and visitors are encouraged to take extra precautions
when outside.

.LONG TERM...Friday through Tuesday...

The pre-frontal trough will move into the area Friday and Friday
night and merge with the cold front sagging south toward the area
on Sunday night. High pressure will move into the Atlantic waters
from the southeastern United States on Monday and cause the cold
front to consolidate just north of the forecast area. On Tuesday
and Wednesday this front is currently forecast to move into the
area with cooler air.

&&

.AVIATION...
(06Z TAFs)

VFR conds are expected to prevail at all TAF sites through the
forecast period. However, brief period of MVFR conds will remain
possible at TJSJ/TJBQ due to SHRA/TSRA through 22/22-23Z. ESE winds
between 8 to 14 knots to continue with sea breeze variations and
higher gusts through 22/23. No major hazard is expected at this
time. HZ due to Saharan dust is expected through today, but VSBY
should remain P6SM.

&&

.MARINE...Seas are still running 4 to 6 feet in the Atlantic
waters with northerly swell of 3 feet. Seas will generally
diminish through Friday. No small craft advisories are expected
this week.

&&

.BEACH FORECAST...A moderate risk of rip currents is expected on
coasts with a northern exposure through Friday as waves heights
diminish. As seas build again, a high risk of rip currents may
reappear on the north-central coast of Puerto Rico Saturday.

&&

.CLIMATE...Excessive warmth and high humidities persist. Saint
Croix tied their record high yesterday and San Juan tied their
record warm minimum. There are some indications that it could be
even warmer on Wednesday.

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
458 AM AST Wed Oct 23 2024

.SYNOPSIS...Another one or two days of excessive heat remain, but
moisture from a tropical wave moving into the area and southeast
flow caused by the intensification of former Tropical Storm Oscar
off the eastern seaboard of the United States will also increase
to bring some relief and showers and thunderstorms across the
area.


&&

.SHORT TERM...Today through Friday...

Calm and quiet weather conditions prevailed overnight across the
islands. Radar and satellite observations showed isolated showers
over the Caribbean waters with few of them reaching the southeastern
portions of Puerto Rico and St. Croix. Warmer minimum temperatures
were seen along the coastal portions of the islands ranging from the
upper 70s to the lower 80s. Meanwhile, temperatures remained in
the upper 60s to lower 70s along portions of the Cordillera
Central. Winds were light and variable at less than 10 knots.

A broad moisture field associated with a tropical wave crossing the
Lesser Antilles is now entering the region. Therefore, an increase
in shower activity is expected today across the local area. The
latest precipitable water model guidance has values of 1.95 to 2.15
inches suggesting a wet and unstable weather pattern for the rest of
the workweek.

The remnants of Tropical Storm Oscar will move rapidly north
northeast into the western Atlantic and the low will intensify
while it loses its tropical characteristics. This will pull winds
from the Caribbean southeast of us along with the better moisture.
Under this southeasterly wind flow, afternoon convective activity
will develop over the interior towards northwestern Puerto Rico
today. Surface winds will back from the southeast to the east
tonight into tomorrow. With this pattern, the U.S. Virgin Islands
will observe an increase in passing tradewind showers during the
morning hours with minimal accumulations. Meanwhile, in Puerto
Rico shower and thunderstorm activity will develop across the
western municipalities and adjacent municipalities. During the
afternoon hours "El San Juan streamer" could form over the San
Juan metro area. With the expected activity, urban and small
stream flooding, quick river rises, and hazardous driving
conditions are likely, especially during the afternoon hours. By
Friday into the weekend, a pre- frontal trough will move near our
area, increasing, once again, the shower development of the area.

The heat trend continues across our region and temperatures are
likely to continue above normal for the next several days. Highs
will reach the upper 80s to lower 90s across the coastal and
urban areas of the islands, and from the lower to mid 80s along
the higher elevations.

.LONG TERM...Friday through Wednesday...

As the low pressure left over from Tropical Storm Oscar weakens
and moves into the northwestern Atlantic. The associated cold
front that was moving through the Bahama Islands will be joined by
another weaker front from the northwest and easterly flow across
the tropical Atlantic will force a prefrontal trough ahead of that
front to cross the U.S. Virgin Islands and Puerto Rico and join
the front from the south on Friday and Friday night. Southeast
flow over the area and the Caribbean waters to the south will
cause the western part of the front to move back into the Bahamas
such that the eastern end of the front hangs just north of the
forecast area through Tuesday with moisture moving over us from
the southeast. A broad low pressure will also develop during the
early part of next week over the western Caribbean to reinforce
this southeasterly flow. This rather complicated scenario will
keep precipitable water values over the area fairly high ranging
from 1.95 inches on Friday to 2.25 inches on Tuesday. At the same
time instability in the area will gradually increase to keep a wet
and showery regime over the area with nuisance flooding expected
in the areas with heavy rain.

&&

.AVIATION...
(06Z TAFS)

Mainly VFR conds are expected to prevail across all TAF sites
through the forecast period. A tropical wave will increase SHRA/TSRA
across the local area today causing brief MVFR conds at
TJSJ/TJBQ/TJPS through 23/23Z. Winds will continue from the SE
between 8 to 14 knots with sea breeze variations and higher gusts
through 23/22-23Z. No major hazard is expected at this time.

&&

.MARINE...

Low pressure will be moving rapidly away from the forecast area
today and Thursday, but at the same time that low pressure will be
intensifying such that by Saturday higher seas and swell will be
affecting the area. Nevertheless, at this time, small craft
advisory conditions are not expected in the forecast area through
the end of the month.

&&

.BEACH FORECAST...

A moderate risk of rip currents will persist across most of the
beaches with northern exposure with the rest of the beaches seeing
a low risk of rip currents through the upcoming weekend.

&&

.CLIMATE...

Today it is very likely that we will get a
temperature over 90 degrees Fahrenheit in San Juan. This will
break another record of the 45th consecutive day with temperatures
above 90 degrees Fahrenheit at the San Juan station since the
local climate records began in 1898. A Heat Advisory will be in
effect at 10 AM AST through 4 PM AST.

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
527 AM AST Thu Oct 24 2024

.SYNOPSIS...

Shower activity will continue today through the weekend with the
approach of a tropical wave into the region. Moisture will
gradually increase by the beginning of the next workweek.
Moderate risk of rip currents for the north-facing beaches of
Puerto Rico, Culebra, St. John, and St.Thomas is anticipated late
this weekend.

&&

.SHORT TERM...Today through Saturday...

Showers and isolated thunderstorms occurred over the local waters
overnight where a few of them drifted cross south central Puerto
Rico, Saint Thomas, Saint John and Saint Croix. Temperatures
continued above normal as lows so far have ranged from the upper 60s
in the higher mountains to the mid 80s on the windward coasts and
over the local waters. A narrow band of concentrated moisture from
one of several pre-frontal troughs is responsible for much of the
convection, some of which is expected to spawn showers and isolated
thunderstorms downstream from El Yunque and in western and interior
Puerto Rico beginning this morning. Then later today somewhat drier
air will move in and linger until late Thursday night. The remnants
of Tropical storm Oscar have intensified and moved north such that
they are now about 1160 miles due north of Aguadilla, PR. High
pressure at the surface in the north central part of the North
Atlantic about 2250 miles east northeast of Saint John is ridging
into the northeastern Caribbean Sea and causing winds to become
fairly light here. As the low retreats and the high moves east winds
will become more easterly and another band of moisture embedded in a
tropical wave will approach the area. These easterly winds and
abundant moisture will continue across the area through the weekend
bringing weather more typical of summer. This is also due to mid and
upper level ridging across the area during the period, that will
limit convection, but hold the above normal temperatures. The GFS
suggests that temperatures will be moderating, but 90 degree-plus
highs look like they will last through at least Saturday.

&&

.LONG TERM...Sunday through Thursday...

Weather conditions are expected to be variable on Sunday, with
easterly winds bringing patches of dry and moist air into the
region. The latest model guidance suggests Precipitable Water (PWAT)
values gradually increase near the above of the climatological
normal from Monday onwards. Wind flow will turn from the northeast
and will prevail until Friday due to a trough and high pressure
lingering in the western Atlantic. A TUTT will increase instability,
promoting deep convection activity on Thursday. Therefore, shower
and thunderstorm activity will increase flooding risk until the end
of the period. Rainfall accumulations may result in urban and small
streams flooding, with possible isolated flash floods. A limited
heat risk over the urban and coastal areas of Puerto Rico and the
U.S. Virgin Islands will prevail for the rest of the forecast
period.

A broad low pressure is expected to develop over Central America
early next week, however, none of the latest model solutions are
positioning tropical systems over the region. Nevertheless,
recommendations are to stay informed by following the National
Hurricane Center and the National Weather Service, San Juan Office.

&&

.AVIATION...

(06Z TAFS)

SHRA and isolated TSRA continue across the local waters with heavy
rain affecting ocnly TIST before 24/14Z. Aft 24/24Z winds will be
ESE-SE 8-12 kt with hir gusts nr TSRA and in sea breezes. Although
VFR conds will prevail, SHRA will provoke MVFR/IFR conds and some
mtn obscurations. SHRA will spread from E to W btwn 24/10Z-16Z.
SHRA/TSRA will dvlp ovr wrn and interior PR and downstream from El
Yunque aft 24/15Z. Max winds NE 17-20 Kt btwn FL450-480. Winds
VRB and less than 10 kts btwn FL090-430.

&&

.MARINE...

Light to gentle southeast winds will gradually become east northeast
tonight into Friday followed by a tropical wave. Gentle to moderate
easterly winds will return by tomorrow into the weekend. The weak
northerly swell spreading across the area will continue to diminish
through tonight. Isolated thunderstorms will remain possible over
the local waters.

&&

.BEACH FORECAST...

A moderate risk of rip currents will persist across most of the
north-facing beaches of Puerto Rico and Culebra, with the rest of
the beaches seeing a low risk of rip currents for the next few
days.

&&

.CLIMATE...

Excessive warmth and high humidities persist. Both St. Croix and
San Juan broke their high temperature record yesterday of 92 and
95 degrees Fahrenheit to 93 and 96 degrees Fahrenheit respectively.
They also broke another warm low temperature record. See the
Record Event Reports for St. Croix (RERISX) and San Juan
(RERSJU) for more details. Additionally, yesterday marks 45
consecutive days with temperatures above +90 degrees Fahrenheit in
the San Juan area.

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
502 AM AST Fri Oct 25 2024

.SYNOPSIS...

We anticipate an increase in shower and thunderstorm activity
through the weekend with the arrival of a tropical wave and a
front to the north of the region. Moisture will gradually increase
by the beginning of the next workweek.

&&

SHORT TERM...Today through Sunday...

Showers and a few isolated thunderstorms occurred over the local
waters overnight. Some of the showers drifted over Saint Croix and
eastern Puerto Rico, but activity last night was less than that of
Wednesday night. This activity was due to the axis of the best
moisture of a pre-frontal trough somewhat enhanced by an approaching
weak tropical wave that is following the best moisture. Temperatures
continued above normal as lows so far have ranged from the upper 60s
in the higher mountains to 84 degrees on the windward coasts and
over the local waters. The narrow band of concentrated moisture from
the pre-frontal trough is responsible for much of the convection,
some of which is expected to spawn showers and isolated
thunderstorms downstream from El Yunque and in western and interior
Puerto Rico beginning around noon. Then later this afternoon
somewhat drier air will move in and linger through the weekend.

The remnants of Tropical storm Oscar have intensified and continue
to move north. They will pass to the east of Newfoundland today and
tonight. High pressure at the surface in the northeast central part
of the North Atlantic, a little more than 2700 miles northeast of
Saint Croix, is ridging into the northeastern Caribbean Sea and
causing winds to remain fairly light here. As the low retreats and
the high stalls, winds will become more easterly and the band of
moisture associated with the trough will slow as the tropical wave
arrives in the area. These easterly winds and abundant moisture will
continue across the area through the weekend bringing weather more
typical of summer. This is also due to mid and upper level ridging
across the area during the period, that will somewhat limit
convection, but hold the above normal temperatures. The GFS suggests
that temperatures will be moderating, but 90 degree-plus highs look
like they will last well beyond Sunday.

&&

.LONG TERM... Monday through Friday...

A wet pattern is anticipated for the long-term period. Model
guidance continues suggesting an increase of Precipitable Water
(PWAT) values reaching above the climatological normal from Monday
onwards. Shower and thunderstorm activity will enhance, with limited-
to-elevated flood risk for the rest of the forecast period. Easterly
to northeasterly winds will turn with a southerly component later on
Tuesday, pulling high moisture content into the region. The latest
model solutions expect a broad low pressure developing across the
Caribbean waters near Panamá to gradually intensify, but not
expected to move across the region. However, we may expect shower
and thunderstorm activity may be expected by the end of the
workweek. Recommendations are to stay informed by following the
National Hurricane Center and the National Weather Service, San
Juan Office.

A limited to elevated heat risk over the urban and coastal areas of
Puerto Rico and the U.S. Virgin Islands is anticipated for the
forecast period.

&&

.AVIATION...

(06Z TAFS)

Sct SHRA continued ovr the lcl waters and the USVI and will begin
spreading across PR aft 25/09Z. By 25/16Z, SHRA/isold TSRA will
begin dvlpg across wrn and interior PR and cont thru arnd 25/22Z. An
area of drier air will follow aft 25/21Z. Wind flow consists of
light land breezes and up to 10 kts in the USVI. Winds just abv the
sfc are easterly 10-15 knots, but will turn somewhat SE during the
day. Sea breezes will begin arnd 25/14Z. Winds blo FL540 were less
than 20 kt.

&&

.MARINE...

Light to moderate east to east-southeast winds will prevail today
followed by as tropical wave. Winds will turn from the east through
the weekend and early next week. Showers and isolated thunderstorms
will remain possible over the local waters.

&&

.BEACH FORECAST...

The rip current risk will increase later today on the north-facing
beaches of Puerto Rico and Culebra, with a low risk elsewhere.
However, the risk is anticipated to spread through the beaches in
the northeast of Puerto Rico, and the U.S. Virgin Islands tonight
through the weekend.

&&

.CLIMATE...

Another high-temperature record was broken yesterday in the San Juan
area. The Luis Muñoz Marín Airport station registered a maximum
temperature of 95 degrees Fahrenheit, breaking the previous record
of 94 degrees Fahrenheit set in 1979. The minimum temperature
registered was 82 degrees F, breaking also the previous record set
last year.

The U.S. Drought Monitor reported abnormally dry levels in portions
of the northcentral, southwestern, and southeastern coastlines of
Puerto Rico and St. Thomas in the U.S. Virgin Islands. For more
information, please refer to the National Drought Summary for
October 22, 2024, at www.droughtmonitor.unl.edu/Summary.aspx.

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
520 AM AST Sun Oct 27 2024

.SYNOPSIS...

Northerly swell will promote a high risk of rip currents today
across the north-facing beaches of Puerto Rico. Winds will gradually
shift from the east to northeast by midweek. A wet and unstable
weather pattern is anticipated from mid-week onward as a frontal
boundary and polar trough approach the area.


&&

.SHORT TERM...Today through Tuesday...

Passing showers moved overnight across the local waters and portions
of northcentral Puerto Rico, but rainfall accumulations were
minimal. Today, weather conditions will be similar to yesterday.
Passing showers over eastern Puerto Rico in the morning and, as the
day progresses, convective activity with showers and thunderstorms
over the Cordillera Central and portions of west and southwestern
Puerto Rico will promote urban and small streams flooding over these
areas. Temperatures will slightly decrease, however, the heat risk
will be limited for all coastal areas of Puerto Rico, Vieques,
Culebra, and the U.S. Virgin Islands. This heat level may impact
individuals extremely sensitive to heat, particularly with long sun
exposure and without adequate hydration.

The latest model guidance has consistently shown an increase of
precipitable water (PWAT) values above the climatological normal
from tomorrow onwards. A mid-level ridge lingering near the forecast
area will limit deep convection activity. However, due to the
combination of the available moisture, diurnal heating, and local
effects, the most likely scenario would be showers and thunderstorms
each afternoon of the short-term period, increasing the potential of
flooding risk over Cordillera Central once again and portions of
west and southwest Puerto Rico. Rainfall accumulations in roads and
poorly drained areas could promote urban and small stream flooding.

A limited heat risk will prevail across the forecast area for the
rest of the period.

.LONG TERM...Wednesday through Sunday...

A broad area of high pressure is expected to build over the western
Atlantic, centering over Bermuda by Friday. This will promote
moderate to fresh east to northeast winds across the northeastern
Caribbean by midweek. An old frontal boundary, or the remnants of
a front, will move over the islands between late Tuesday night and
Wednesday, by these northeasterly winds. As a result, an increase
in cloud coverage and shower activity is expected across the
islands.

A deep mid-to upper-level trough is expected to move in from the
west/northwest by Thursday, creating favorable conditions for
thunderstorm development through the end of the workweek. A broad
area of low pressure at the surface is expected to develop under
the influence of the trough, and a southerly wind flow is expected
to prevail from Thursday onwards across the eastern Caribbean.
This pattern usually favors pooling of tropical moisture over the
islands, and a wet and unstable period could unfold during the end
of the month/beginning of November. This coincides with the
enhanced rainfall phase of the Madden-Julian Oscillation (MJO),
therefore, the long-term forecast favors shower and thunderstorm
development across the local area.

High temperatures in general should decrease by a few degrees
across most areas as the wind shifts from the northeast and
cloudiness increases over the region.


&&

.AVIATION...

(06Z TAFS)

Mainly VFR conds expected across all terminals. However, diurnally
induced SHRA/TSRA over western interior may cause tempo MVFR conds
and mtn tops obscd in and around TJPS/TJBQ fm 16z-22z. Winds will
prevail from the east at 8-14 kt with sea breeze variations and
stronger gusts aft 14z. HZ due to Saharan dust continues over the
local area but VSBY will remain P6SM.


&&

.MARINE...

Light to moderate east winds will prevail through at least Monday. A
broad surface high pressure over the western Atlantic will push the
remnants of a front across the local area by midweek. This will aid
in promoting moderate to fresh, but locally strong, northeast winds
and hazardous seas. An increase of shower and thunderstorm activity
across the regional waters is also expected by the end of the
workweek.



&&

.BEACH FORECAST...

A northerly swell will continue across the Atlantic waters and
passages today. There is a high risk of rip currents for all west
to northeast beaches of Puerto Rico. Thunderstorms with occasional
lightning strikes are expected this afternoon over the coastal sections
of west/southwest PR. Across the USVI and Culebra, a moderate
risk of rip currents continues.

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
549 AM AST Mon Oct 28 2024

.SYNOPSIS...

Today, expect a gradual transition into a wetter and more
unstable weather pattern. Several features will combine to
maintain this weather pattern through at least next weekend.
Extremely hazardous marine and coastal conditions are also
anticipated from Thursday through the weekend. Please continue to
monitor the forecast as this event unfolds.

&&

.SHORT TERM...Today through Wednesday...

A few showers moved over land areas just before sunset, leaving
mostly minor rainfall accumulations in St. Croix and eastern Puerto
Rico. Minimum temperatures were from the mid 60s across the higher
elevations of PR to the upper 70s and low 80s across the coastal
sections of the islands. Winds were up to 10 mph or less from the
east with land breeze variations.

For today, another active afternoon is expected mainly over the
interior and western sections of Puerto Rico due to diurnally
induced showers and thunderstorms. Urban and small stream flooding
is expected with this activity. Also, the San Juan streamer could
develop once again and ponding of water or minor flooding is
possible across San Juan and nearby municipalities. Daytime
temperatures are expected to reach the low 90s across coastal areas
with heat indices exceeding 106F in some locations.

For Tuesday and Wednesday, a wet and unstable weather pattern is
expected as a lingering front just north of the area sinks
southwards across the islands. This will be driven by moderate to
fresh northeasterly winds and temperatures are expected to decrease
by a few degrees in general across Puerto Rico and the northern
USVI. The main weather impacts due to excessive rainfall will be
urban and small stream flooding, localized flash flooding, and
mudslides in areas of steep terrain.

&&

.LONG TERM...Thursday through Monday...

The inherited forecast remains unchanged. The latest model
guidance continues to suggest a broad surface of high-pressure
building over the western Atlantic, promoting moderate to fresh
east-to- northeast winds across the northeastern Caribbean through
early Friday. This wind flow will continue to filter the remnants
of an old frontal boundary over the islands on Thursday.

A deep mid-to upper-level trough is expected to move in from the
west/northwest by Thursday, creating favorable conditions for
thunderstorm development through the end of the workweek. A broad
area of low pressure at the surface is expected to develop under
the influence of the trough, and a southerly wind flow is expected
to prevail from Friday onwards across the eastern Caribbean. This
pattern usually favors the pooling of tropical moisture over the
islands.

A wet and unstable period could unfold during the end of the
month/beginning of November as the National Hurricane Center is
monitoring an area of low pressure that is likely to develop over
the southwestern Caribbean Sea. They anticipate a gradual
development late this week or over the weekend as the system
begins to drift northward or northeastward and potentially
approach the forecast area. This area of low pressure now has a 40
percent chance of development in the next 7 days. However, it is
far in the forecast, and we encourage people to stay informed with
each update.

Through the long term period, we anticipate the high temperatures
staying below 90 degrees across most areas as the cloudiness
increases over the region.

&&

.AVIATION...
(06Z TAFS)

Mainly VFR conds expected across all terminals. However, diurnally
induced SHRA/TSRA over western interior may cause tempo MVFR conds
and mtn tops obscd in and around TJPS/TJBQ fm 16z-22z. Winds will
prevail from the east at 7-13 kt with sea breeze variations and
stronger gusts aft 14z.

&&

.MARINE...

Gentle to moderate east winds will prevail through tonight. A broad
surface high pressure building over the western Atlantic will push
the remnants of a front across the local area by midweek. This will
aid in promoting moderate to fresh, but locally strong, northeast
winds and hazardous seas. An increase in shower and thunderstorm
activity across the regional waters is also expected by the end of
the workweek.

&&

.BEACH FORECAST...

A northerly swell will continue across the Atlantic waters and
passages today. There is a high risk of rip currents for all
northwestern to northeastern beaches of Puerto Rico. Thunderstorms
with occasional lightning strikes are expected this afternoon
over the coastal sections of west and interior PR. Across the USVI
and Culebra, a moderate risk of rip currents continues.

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
442 AM AST Tue Oct 29 2024

.SYNOPSIS...

A gradual transition into a wetter and more unstable weather
pattern is expected over the next few days, particularly between
late Wednesday into Thursday. Several features will combine to
maintain this weather pattern over the next 4-7 days, including
the proximity of a tropical disturbance by early next week.
Extremely hazardous marine and coastal conditions are also
anticipated from Thursday through the weekend. Please continue to
monitor the forecast as this event unfolds.

&&

.SHORT TERM...Today through Thursday...

A broad surface high-pressure building over the western Atlantic is
promoting moderate to fresh east-to-northeast winds across the
northeastern Caribbean. Under these northeasterly steering winds, a
meandering frontal boundary to our north will move over the islands
today through early Wednesday. As shower and cloud coverage
increases over the islands, daytime temperatures will decrease by a
few degrees across Puerto Rico and the U.S. Virgin Islands.
Furthermore, another front will arrive across the area on Thursday
as the surface high centers near Bermuda. Therefore, a wetter
pattern is expected to unfold across the area, with showers and
thunderstorms increasing in areal coverage. In addition, a polar
trough is forecast to move over the region by Thursday, providing
more instability and favorable conditions for thunderstorm
development. Meanwhile, over the southwestern Caribbean Sea, a broad
area of low pressure is forecast to develop, and this will continue
to promote the pooling of tropical moisture under southerly winds
across the Caribbean. Urban and small stream flooding is expected
each day across the islands, with localized flash flooding and
mudslides in areas of steep terrain.

Tightening of the local pressure gradient and a shearline associated
with the front on Thursday will increase winds between 20 and 25
knots or higher across the Atlantic waters. Therefore, breezy to
windy conditions are possible along the Atlantic coastal
municipalities of Puerto Rico and across the northern U.S. Virgin
Islands.

&&

.LONG TERM...Friday through Tuesday...

The most recent guidance continues to suggest a deep mid-to
upper-level trough across the forecast area by the end of the
workweek. This weather feature will create favorable conditions
for thunderstorm development. A broad area of low pressure at the
surface is expected to develop under the influence of the trough,
and a southerly wind flow is expected to prevail from Friday
onwards. This pattern usually favors the pooling of tropical
moisture over the islands.

A wet and unstable period could unfold during the end of the
month/beginning of November as the National Hurricane Center is
monitoring an area of low pressure that is likely to develop over
the southwestern Caribbean Sea. They anticipate a gradual
development late this week or over the weekend as the system
begins to drift northward or northeastward and potentially
approach the forecast area. This area of low pressure continues to
have a 40 percent chance of development in the next 7 days.
However, it is far in the forecast, and we encourage people to
stay informed with each update.

In the long term, we anticipate temperatures below 90 degrees across
most areas as the cloudiness increases over the region.

&&

.AVIATION...
(06Z TAFS)

Mainly VFR conds expected early in the forecast cycle. SHRA/TSRA are
expected to increase aft 29/12z across the northern and eastern
terminals of the islands as a frontal system over the Atlantic
waters approach the area. Tempo MVFR to brief IFR conds and mtn tops
obscd are possible from around 29/16z onwards. Winds will prevail
from the ENE at 12-17 kt with sea breeze variations across the
southern coast of PR. Stronger gusts and lower CIGS due to FROPA aft
29/20z.

&&

.MARINE...

Moderate to fresh easterly winds will prevail through Wednesday. A
broad surface high pressure building over the western Atlantic will
yield moderate to locally strong, northeasterly winds today, pushing
the remnants of a front across the local area through midweek. An
increase in shower and thunderstorm activity is also expected across
the regional waters and passages through the rest of the workweek
into the weekend.

&&

.BEACH FORECAST...

A northerly swell will continue across the Atlantic waters and
passages today. There is a high risk of rip currents for
northwestern to eastern beaches of Puerto Rico. Thunderstorms with
occasional lightning strikes are expected this afternoon. Across
the USVI and Culebra, a moderate risk of rip currents continues.

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
627 AM AST Thu Oct 31 2024

.SYNOPSIS...

A series of mid-to-upper level troughs and above-normal moisture
from a nearly stationary front will create ideal conditions for
thunderstorm development over the next few days, with the most
intense and frequent activity expected through at least Saturday
morning.A Flash Flood Watch is in effect through at least 8 AM
on Saturday. Residents and visitors are urged to pay attention to
the local agency's guidance.

Marine- wise, small craft operators and beachgoers should monitor
the beach and water conditions due to wind-driven seas and a
northerly swell that will affect the local waters for the next
several days.

&&

.SHORT TERM...Today through Saturday...

Active weather conditions prevailed overnight across northeast and
east Puerto Rico and the U.S. Virgin Islands, where rainfall
accumulations ranged mainly between 1 and 3 inches with isolated
higher amounts of up to 4 inches (based on radar estimates).
Finally, low temperatures were in the mid-70s across the coastal
areas and in the mid-60s in mountains and valleys. Winds were
between 5 and 15 mph from the northeast but locally higher near rain
activity.

An upper-level trough and abundant tropical moisture will result in
an unstable wet pattern through Saturday. Given the expected
conditions, a Flood Watch is in effect for Puerto Rico and the U.S.
Virgin Islands due to the high potential (70-90%) to observe
flooding. The highest rainfall accumulation will range between 6 and
8 inches across the northeast quadrant of PR and 4 to 6 inches
across the rest of the eastern third of PR and the U.S Virgin
Islands. Soils are saturated across the NE quadrant of PR, Vieques,
and the U.S. Virgin Islands; thus, the expected additional rains
will result in river and flash flooding and mudslides.

Residents and visitors are urged to stay alert and closely monitor
weather updates and official warnings during flooding events. It is
essential to avoid crossing flooded roads or areas, as even shallow
water can be extremely dangerous. Just a few inches of moving water
can sweep people off their feet, and one foot of water can carry
away most vehicles.


.LONG TERM...Sunday through Wednesday...

A surface high-pressure system located over the Western Atlantic
will continue to interact with a broad low-pressure system in the
Central Atlantic, generating southeasterly winds across Puerto
Rico and the U.S. Virgin Islands. Early in the weekend, a trough
is expected to develop in the region. The combination of these
weather features may lead to the accumulation of tropical moisture
over the islands. We anticipate a wet and unstable period lasting
at least until November 5th, 2024, which coincides with Election
Day. The latest Precipitable Water model indicates values
exceeding 2.0 inches, which is above the 75th percentile and
considered higher than normal for this time of year. The
National Hurricane Center continues to monitor an area of low
pressure that is likely to develop over the southwestern Caribbean
Sea. This system is expected to gradually develop over the
weekend and early next week as it drifts northward over the west-
central Caribbean. Currently, there is a 40 percent chance of
development for this low-pressure area within the next seven days.
Since this forecast is still far off, we encourage everyone to
remain informed with each update. Some potential hazards
associated with the anticipated wet and unstable conditions
include ponding of water on roads and in poorly drained areas,
which could lead to flooding or occasional flash flooding with the
heaviest rainfall activity, lightning, quick rises in small
rivers, and landslides in higher terrains. We urge people to drive
carefully, stay aware of the updates issued by our local forecast
office, and remember to carry an umbrella everywhere, even on
Election Day. In terms of temperatures, primarily cloudy skies and
unstable weather conditions are expected to keep high
temperatures below 90 degrees across most areas throughout the
long-term period.

&&

.AVIATION...

(06Z TAFS)

An unstable weather pattern will bring SHRA/TSRA across the local
flying area. TEMPOs for MVFR or IFR conditions will be required,
especially for JSJ/IST/ISX. Winds will persist from the NE at 5 to
15 kt with higher gusts and sea breeze variations aft 31/13z. Winds
will become calm to light and variable aft 31/23z.


&&

.MARINE...

Moderate to fresh easterly winds will prevail today and become east
southeast Friday and Saturday. A broad surface high pressure building
over the western Atlantic will hold the remnants of a cold front in
the local area until a weak low pressure deepens over our local
western Atlantic waters. A pulse of northerly swell will also result
in building seas through at least Saturday. Showers and
thunderstorms will persist across the regional waters and passages
into the following week.


&&

.BEACH FORECAST...

Hazardous coastal conditions are expected over the northern coast
of Puerto Rico, Culebra, and the US Virgin Islands. Hazardous
breaking waves will impact the north-facing beaches of Puerto
Rico. Therefore a High Surf Advisory is in effect for the Atlantic
coastline of Puerto Rico. A high rip current risk will be in
place due to hazardous breaking waves of 7 feet or more across
all the northern exposed beaches of Puerto Rico and US Virgin
Islands. Residents and visitors should avoid the north exposed
beaches of Puerto Rico for the next several days.

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
501 AM AST Fri Nov 1 2024

.SYNOPSIS...

Upper level troughs promoting plenty of instability and an atmosphere
loaded with water around a cold front slowly retreating from the
local area will keep condtions wet through at least mid week next
week. A flash flood watch will remain in place until at least Saturday.
Southerly winds will diminish through the weekend but light to gentle
easterly winds will return early next week. Seas will remain hazardous
until Sunday with a high risk of rip currents through Monday.

&&

.SHORT TERM...Today through Sunday...

Fairly active night as upper-level troughs and induced surface
low continues to impact the forecast area. Highest rainfall
accumulations were concentrated across the eastern portions of
Puerto Rico with several river gauges reaching minor to moderate
flood stages. Rio Guayanes in Yabucoa briefly reached major flood
stage before rapidly decreasing as shower activity and excessive
runoff diminished. Shower and thunderstorm activity continues
mostly across the regional waters moving onshore over eastern
portions of Puerto Rico, Vieques, Culebra and northern USVI.
Expect activity to continue for the rest of the morning hours.
This could potentially result in urban and small stream and river
flooding and landslides.

A cut-off low at upper-levels and induced surface trough will
persist across the area, gradually moving northwest in the next few
days. This will move the moisture associated with a cold front over
the area to the north, but will also bring up a very warm and moist
air mass from the central Caribbean Sunday. High pressure at the
surface over the western Atlantic will not let the cold front move
too far to the north and will cause it to be near by when an
easterly wave moves in from the east. This will bring more showers
and thunderstorms on Friday and some drying on Saturday. Then
moisture from the Caribbean as described above will bring another
round of showers and thunderstorms in southeast to south low level
flow on Sunday. This will complicate areas that have already being
impacted by previous rains, particularly across the eastern third of
Puerto Rico and smaller islands. Soils are already saturated and
streamflows are running well above normal. Therefore, expect
elevated to significant flooding risk and landslides through the
weekend.

.LONG TERM...Monday through Friday...

The long term period is more uncertain, since the trajectory of
the best moisture will depend on the position and strength of the
low generated in the vicinity of the cold front over the weekend.
Nevertheless current model solutions hold the precipitable water
above 2 inches through Wednesday and well above normal for the
season which is about 1.7 inches. Although the best moisture is
expected to be west of the area and southerly flow will contribute
to some above normal temperatures, numerous periods of active
showers and thunderstorms are expected until later next week.
At upper levels a ridge will intrude from the south until a
shortwave passes northeast of the area Tuesday night. This is
forecast to quickly become a TUTT low which returns directly over
eastern Puerto Rico Thursday and pushes over to the Mona Passage
by the end of Friday giving moisture another boost ahead of yet
another easterly wave entering the area. Current indication are
for another wet weekend after Friday the eighth.

&&

.AVIATION...
(06Z TAFS)

An unstable weather pattern will bring SHRA/TSRA across the local
flying area. Expect BKN to OVC ceilings between FL020 and FL080.
TEMPOs for MVFR or IFR conditions will be required, especially for
JSJ/IST/ISX. Winds will persist from the NE at 5 to 15 kt with
higher gusts and sea breeze variations aft 01/13z. Winds will become
calm to light and variable aft 01/23z.

&&

.MARINE...

Winds have become east southeast and will remain so through Saturday.
A broad surface high pressure building over the western Atlantic will
hold the remnants of a cold front in the local area until a weak low
pressure deepens over our local western Atlantic waters. A pulse of
northerly swell will also result in building seas through at least
Saturday. Showers and thunderstorms will persist across the regional
waters and passages into the following week.

&&

.BEACH FORECAST...

Nearshore buoys indicate wave heights of 10 feet, with breaking
waves estimated up to 14 feet. These large breaking waves will
create dangerous swimming conditions and may cause minor beach
erosion. Consequently, High Surf Advisories and High Rip Current
Statements will remain in effect. For more information, please
refer to SRFSJU and CWFSJU. Continue to monitor the forecast as
this event unfolds.


&&

.CLIMATOLOGY...

This may be the wettest 7 day beginning on Halloween on record.
The previous record was set in 1992 with 6.30 inches at San Juan.
Here at the office we have already had a total of 5.58 inches
yesterday. With 6 days to go in a very wet period.

&&

.HYDROLOGY...

A moist unstable weather pattern will prevail due to the combination
of abundant tropical moisture and a mid to upper-level trough.
Rainfall totals during this period are expected to range from 2 to
4, with locally higher amounts of 5 inches across northern and
eastern Puerto Rico, Vieques, Culebra, and the U.S. Virgin Islands.
Elsewhere, expect rainfall amounts around 1 to 2 inches.

Due to the high likelihood that any extended period of moderate to
heavy rainfall will lead to flash flooding, sudden river surges
potentially causing some rivers to exceed flood-stage levels—and
mudslides in areas with steep terrain, a Flash Flood Watch has been
extended.

Although uncertainties are present, unsettled weather conditions
will likely continue from Sunday into early next week. Residents and
visitors, especially those in flood-prone areas or planning outdoor
activities in the coming days, are advised to closely monitor the
latest weather forecasts.

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
515 AM AST Sat Nov 2 2024

.SYNOPSIS...

The wet and unsettled weather pattern will continue through the
forecast period. Extremely hazardous marine and coastal conditions
are also expected to persist through the weekend and into at least
early next week. Please continue to monitor the forecast as this
event unfolds.

&&

.SHORT TERM...Today through Monday...

Showers and thunderstorms affected the USVI, especially the northern
one, from late Friday night to early Saturday morning, when rain
activity dissipated, leaving tranquil weather conditions for the
rest of the early morning hours. Calm weather conditions prevailed
across PR. Low temperatures were in the mid-70s across the coastal
areas and in the low-60s in mountains and valleys. Winds were
between 5 and 15 mph from the east-southeast with land breeze
variations.

Please be advised that although the Flood Watch has been canceled,
the soils continue to be saturated, and the river levels are running
above normal. An unstable and wet weather pattern will persist
through at least Monday. Consequently, the afternoon thunderstorms
expected today and the showers and thunderstorms forecasted for
Sunday will have an elevated risk of flooding across the islands.
Therefore, it is essential to be cautious in these areas.

A TUTT-low will linger across the Northeast Caribbean, promoting
instability over PR/USVI. While at low levels, a surface low, now
being monitored by the NHC and with a low chance of tropical cyclone
formation, will promote a southerly wind flow while it moves
westward away from the islands. This southerly wind flow will pool
abundant tropical moisture across the islands through early Monday
morning. You can expect calm weather today, with the first round of
showers and thunderstorms during the afternoon, then another round
of moderate to heavy rains during the late night hours into early
Sunday morning. Sunday looks like the wettest day of the short term.

.LONG TERM...Tuesday through Saturday...

Model guidance consistently indicates that a wet and unsettled
weather pattern will persist through the long-term forecast period.
A series of upper-level troughs and surface-induced lows are
expected to move over the region. Additionally, the Madden-Julian
Oscillation (MJO) is forecast to shift into and across the Western
Hemisphere, enhancing upper-level divergence across the area. These
favorable dynamics will combine with near to well-above-normal
moisture levels. The Climate Prediction Center forecasts a 50% to
65% probability of above-normal rainfall across the northeastern
Caribbean from midweek next week into the weekend.

Some uncertainty remains, as the GFS model has consistently
developed closed circulation features over or just north of our area
between Wednesday and Thursday in recent model cycles. However, the
ECMWF model has been much weaker with these solutions, with other
global models showing similar outcomes. It is too early in the
forecast period to determine what, if any, tropical impacts may
occur. Despite this uncertainty, models are fairly consistent in
indicating the continuation of a wet and unsettled pattern.
Consequently, the elevated to locally significant flooding risk will
persist, particularly as saturated soils will exacerbate excessive
runoff in areas most affected by previous rains. This could lead to
urban and small stream flooding, with flash flooding in flood-prone
areas. Rapid river rises and landslides are also possible in steep
terrain.


&&

.AVIATION...
(06z TAFs)

VFR conditions will prevail during the morning hours. By the
afternoon, SHRA/TSRA will develop mainly across the southeast,
north, and northeast PR and near the northern USVI, increasing the
risk of impacting local terminals (JSJ/IST/ISX). Winds will remain
calm to light and variable after 02/13z from the ESE-SE at 5 to 10
kt with higher gusts and sea breeze variations.

&&

.MARINE...

A broad surface high pressure building over the western Atlantic
will keep the remnants of a cold front from moving very much north of
the local area. A weak low pressure deepens just north of the
Dominican Republic and will promote south to southwesterly wind flow.
A pulse of northerly swell will also continue to maintain hazardous
seas through Sunday and even Monday. Showers and thunderstorms will
persist across the regional waters and passages into the following
week. Another long period northeasterly swell will arrive to the
local waters on Monday.

&&

.BEACH FORECAST...

Northern nearshore buoys indicate wave heights of 8-9 feet, with
breaking waves estimated to reach up to 13 feet. These large
breaking waves will create hazardous swimming conditions and may
lead to minor beach erosion. As a result, High Surf Advisories and
High Rip Current Statements remain in effect. For more information,
please refer to SRFSJU and CWFSJU. Continue to monitor the forecast
as this event unfolds.

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
509 AM AST Sun Nov 3 2024

.SYNOPSIS...

Variable weather conditions are expected today as the trough
gradually weakens. A fairly active second half of the workweek is
possible, although some uncertainty makes it challenging to assess
potential impacts across the forecast area. Hazardous marine and
coastal conditions will persist through at least Monday and are
expected to return by midweek, continuing into the weekend.


&&

.SHORT TERM...Today through Tuesday...

The US Virgin Islands had another active night, with thunderstorms
producing heavy rain and gusty winds overnight. Also, Vieques,
Culebra and NE-PR were affected by this activity overnight.
Meanwhile, most of mainland PR observed calm weather conditions.
Winds continued from the south, and low temperatures were in the mid-
70s across the coastal areas and in the low-60s in mountains and
valleys.

The mid to upper-level trough will slowly weaken throughout the day,
limiting instability across the Northeast Caribbean. At low levels,
a trough of low pressure (monitored by the NHC and with a low chance
of tropical cyclone formation) continues to promote a southerly wind
flow as it moves westward away from the islands. This southerly wind
flow will pool abundant tropical moisture across the islands,
promoting above-normal heat index values today through Monday. After
the overnight and early morning showers and thunderstorms that
affected the USVI and eastern PR dissipated, you can expect calm
weather through the morning hours before the round of afternoon
showers, and thunderstorms developed one more time. The southerly
winds will promote the arrival of showers across southern PR and the
USVI throughout the morning and, in the afternoon, will spread into
the northern sections of PR.

A surface high-pressure building across the western Atlantic will
favor the return of the east to east-southeast winds on Monday. As a
result, we can expect a mixture of sunshine and clouds during the
morning, with afternoon convection across the interior and northwest
quadrant. On Tuesday, a TUTT low building from the NE over the
Northeast Caribbean will induce a surface perturbation that will
arrive, increasing moisture and the potential for showers and
thunderstorms by Tuesday afternoon into the evening. Urban and small
stream flooding will likely occur due to the heaviest persistent
thunderstorm activity.

.LONG TERM...Wednesday through Sunday...

On Wednesday, an upper-level trough will continue influencing the
northeastern Caribbean, with a surface-induced low east of the
Leeward Islands promoting unstable weather conditions. As mentioned
in previous discussions, the Madden-Julian Oscillation (MJO) will be
in its Western Hemisphere phase, enhancing upper-level divergence
and further fueling instability across the Caribbean basin
throughout the week.

However, uncertainty persists in the long-term forecast. The GFS
model continues to develop a closed low circulation from the
aforementioned surface-induced trough as it moves over or just north
of the forecast area, while a TUTT-low develops between Thursday and
Friday. The ECMWF model shows a similar feature but depicts it as a
surface inverted trough moving westward by the end of the week.

Looking at the GFS ensemble members, similar scenarios play out,
though they are not as bullish as the parent deterministic model.
The ECMWF Extreme Forecast Index (EFI) suggests that about 50% to
70% of ensemble members indicate increased precipitation across
northern and northeastern Puerto Rico and northern USVI by the
latter part of this week. This points to an above-normal rainfall
event, though not necessarily an extreme one. However, saturated
soils and elevated streamflows from previous rainfall in these areas
could heighten the flooding risk as the surface low approaches.

Despite high uncertainty regarding the strength and positioning of
the surface low, expect a wet and unstable weather pattern through
the end of the workweek. This could lead to an increased flooding
threat, quick river rises, and landslides, particularly across the
eastern half of the CWA. Gusty winds, especially near thunderstorm
activity, can also be expected. For now, continue to monitor the
forecast, as changes in the strength and positioning of the expected
surface low could alter the impacts across the forecast area.

During the weekend, as the TUTT-low and surface trough move
westward, a southerly wind flow will bring tropical moisture,
which could combine with surface heating and local effects,
particularly across the interior and western portions of Puerto
Rico each afternoon.


&&

.AVIATION...
(06z TAFs)

VFR conditions will prevail during the morning hours. SHRA and
isolated TSRA will affect the southern plains of PR and the USVI,
and there is a moderate chance of affecting JPS/IST/ISX, creating
MVFR or even IFR conditions. SHRA/TSRA will spread over PR's
interior and northern portions between 03/15z-23z. Winds will remain
mainly from the south, ranging between 5 and 10 kt, with higher
gusts due to sea breeze and in/near TSRA.


&&

.MARINE...

A broad area of low pressure over the region will promote a weak
southerly wind flow as it drifts westward through the rest of the
weekend. Pulses of northerly swells will maintain hazardous seas
through at least early in the week. For more information, please
refer to MWWSJU text product. Moderate to locally fresh east to
northeast trades return by midweek.

&&

.BEACH FORECAST...

The northern nearshore buoy continues to indicate 9-12 foot
breakers, with additional pulses of a northeasterly swell reaching
our northern waters this afternoon. These large breaking waves will
create hazardous swimming conditions and may lead to minor beach
erosion. As a result, High Surf Advisories and High Rip Current
Statements remain in effect. For more information, please refer to
SRFSJU and CWFSJU text products. Continue to monitor the forecast as
this event unfolds.

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
513 AM AST Mon Nov 4 2024

.SYNOPSIS...
Due to a long period of northeasterly swell, hazardous coastal
conditions will prevail today. Thus, High Surf and Coastal Flood
Advisories are in effect for the north-facing beaches in PR, while
we expect a High Risk of Rip Currents for the US Virgin Islands
north-facing beaches. The east-southeasterly wind flow will
promote warm to hot temperatures during the afternoon, and the
excessive heating and local effects will promote isolated to
scattered vigorous thunderstorm activity today. Instability will
increase from Tuesday onward with the proximity of an upper-level
trough and a surface frontal boundary. Model guidance suggests a
FROPA around the middle of next week before the arrival of an area
of interest monitored by the National Hurricane Center on
Thursday. An unstable and wet pattern may prevail through the
second part of the week.

&&

.SHORT TERM...Today through Wednesday...

Early in the night, a strong thunderstorm developed over the
Caribbean waters, brushing Ponce and moving westward across the
southwestern coastal areas. Shower and thunderstorm activity has
since diminished over land, remaining mostly over the regional
waters. These weather conditions are expected to continue through
the morning hours, with occasional showers moving across windward
coastal areas.

Today, another day of above-normal temperatures is expected. These
hot surface temperatures will combine with higher-than-average
moisture, sufficient instability, and local effects to promote
another round of shower and thunderstorm activity. Under a
southeasterly steering wind flow, this activity will cluster across
the interior and northwestern areas of Puerto Rico, with some
activity also expected in the north-central municipalities and the
San Juan metro area, though to a lesser extent. A limited to
elevated flooding risk is anticipated in these areas.

The short-term forecast indicates a shift toward deteriorating
weather conditions across the area. An upper-level trough is
expected to build over the northeastern Caribbean on Tuesday,
further deepening on Wednesday. Key indicators, including the 250 mb
height field and 1000-500 mb and 1000-850 mb thicknesses, are
projected to drop near or below climatological normals, with steep
low- to mid-level lapse rates. As a result, unsettled weather
conditions are anticipated. At the surface, a high-pressure system
will build over the western Atlantic, shifting winds to a more
northerly component and promoting pleasant temperatures across the
islands. These northerly winds will push a shearline toward the
forecast area on Tuesday, enhancing moisture convergence across the
northern Caribbean. Expect morning showers and thunderstorms to
affect northern coastal areas, with activity later clustering over
the interior and western/southwestern regions of Puerto Rico in the
afternoon.

On Wednesday, a frontal passage (FROPA) may lead to a decrease in
moisture content during the day; however, some convective activity
is still expected in the afternoon. By late Wednesday night, a
surface-induced low is forecast to develop over the northern Leeward
Islands and begin entering the forecast area. The National Hurricane
Center has recently assigned a 20% probability of formation to this
system. Despite this, the wet period is expected to continue, with
an elevated to localized significant flooding risk by midweek,
particularly in areas that have experienced high rainfall
accumulations over the past week. Consequently, urban and small
stream flooding, localized flash flooding, quick river rises, and
landslides may persist throughout the week. Please continue to
monitor the forecast as this event unfolds.

.LONG TERM...Thursday through Sunday...

An area of low pressure monitored by the National Hurricane Center
will move near the islands by Thursday, increasing the potential
for developing a wet and unstable weather pattern from Thursday
onward. This system will promote moisture pooling across the
islands, which, combined with local effects, will result in solid
afternoon convection each day. Then, the above-normal warm sea
surface temperatures will promote night-time scattered to
widespread shower activity across the local waters and windward
sections each day. Additionally, the expected increase in the
easterly winds will promote the inland movement of these showers,
which may result in showery weather from time to time.

&&

.AVIATION...
(06Z TAFs)

Mostly VFR conds will prevail for all TAF sites durg prd. However,
SCT SHRA/Isold TSRA is possible ovr TJBQ/TJSJ after 04/17z. Brief
MVFR expected for these terminals, with ocnl IFR or maybe worse and
Mtn Top obscr across the ctrl mtn range of PR. SE wnds btw 09-12kts,
but stronger, gustier winds near SHRA/TSRA, where winds may be VRB.

&&

.MARINE...
A surface trough moving westward across the northeastern Caribbean
will promote the rest of today's weak east-southerly wind flow. A
surface high pressure building from the western to central
Atlantic will promote the return of the trade winds across the
northeast Caribbean from late tonight into the middle of the week.
Pulses of northerly swells will maintain hazardous seas through
the workweek.

&&

.BEACH FORECAST...
Hazardous coastal conditions will continue today as a
northeasterly swell produces large breaking waves between 8 to 14
feet. CariCOOS Nearshore buoy network at San Juan detected a
northeasterly swell around 6 feet with a 14 to 15-second period,
creating breaking waves between 8 and 13 feet along the north-
facing beaches. Given the conditions, the Coastal Flood and a High
Surf Advisory continue in effect through this evening for the
north coast of Puerto Rico. The north-facing beaches along the US
Virgin Islands and the rest of PR can expect breaking waves around
6 or 7 feet, creating a high risk of rip currents.

[cycloneye]

Area Forecast Discussion...CORRECTED
National Weather Service San Juan PR
520 AM AST Tue Nov 5 2024

.Correction: Adding Small Craft Advisories.

.SYNOPSIS...

Wet and unstable weather conditions are anticipated to persist
over the next few days. This pattern will start with an upper-
level trough and a surface frontal boundary through midweek,
followed by the proximity of an area of low pressure on Thursday
and a strong tropical wave over the weekend, heightening the risks
of flooding and lightning. A break in the weather may be possible
by early next week. Additional hazard risks include strong winds,
particularly during the passage of the low-pressure system and
tropical wave, leading to dangerous marine and life-threatening
rip currents conditions.

&&

.SHORT TERM...Today through Thursday...

Showers and isolated to scattered thunderstorms persisted across the
Atlantic and Caribbean waters, with some of this activity moving
into eastern portions of Puerto Rico. Similar conditions are
expected to continue through the rest of the morning, potentially
leading to ponding of water on roads and in low-lying areas,
primarily across eastern Puerto Rico.

For today and tomorrow (Wednesday), the forecast remains on track
with a slight adjustment in the timing of the shearline's arrival to
the region. As surface high pressure builds across the western
hemisphere, winds will gradually shift to a northeasterly component
by midday. Hot temperatures are still expected across urban and
coastal areas before the northeasterly flow brings more comfortable
conditions for the rest of the short-term period.

A developing streamer downwind of El Yunque could bring shower
activity to the southern portions of the San Juan metro area by
early afternoon. As winds continue shifting northeasterly, a
combination of above-normal moisture, upper-level troughiness,
surface heating, and local effects will support orographically
driven convection across interior and western/southwestern Puerto
Rico, with a limited to elevated flooding risk anticipated in these
areas.

Tonight, the northeasterly winds will push the shearline over the
forecast area, bringing showers and isolated thunderstorms to
northern and northeastern Puerto Rico and the smaller islands. On
Wednesday, the frontal passage (FROPA) will bring some drier air
across the region; however, sufficient moisture and instability
aloft may still support shower and thunderstorm activity across
interior and southwestern Puerto Rico.

Uncertainty remains for the rest of the short-term forecast as the
upper-level trough deepens further and as we monitor the eventual
positioning of a surface-induced low forecast to develop near the
northern Leeward Islands by Wednesday. This surface low is expected
to move westward by late Wednesday into Thursday. The GFS continues
to suggest more bullish solutions, with the 05/00z run now
positioning it slightly southward compared to previous model cycles.
Meanwhile, the ECMWF remains consistent with its inverted trough
solution.

The 05/00z ECMWF QPF EFI now shows values of 0.7-0.8 across the
eastern half of the CWA, indicating a high likelihood of widespread,
significant rainfall in this area. This level of EFI suggests
potential impacts including urban and small stream flooding, flash
flooding in flood-prone areas, and quick river rises. With saturated
soils, there is also an increased risk of landslides and rockfalls
in steep terrain. Due to the existing uncertainty, it is essential
to closely monitor the forecast for possible watches, advisories, or
warnings issued by our local office.

.LONG TERM...Friday through Tuesday...

Wet and unstable weather conditions are forecasted to persist
throughout the long-term period, mainly through the weekend,
resulting in a limited to elevated risk of flooding and lightning
hazards. On Friday, local weather will be influenced by an area of
low pressure currently being monitored by the National Hurricane
Center, which has a low (20 percent) chance of tropical formation
over the next seven days. In contrast, the weather on Saturday and
Sunday will be shaped by the movement of a strong tropical wave
and its associated moisture field, marking the wettest period in
the next 3 to 8 days. While there is low confidence that slightly
drier conditions will enhance the weather by early next week,
model guidance suggests a reduction in above-normal precipitable
water values across the region. Warm to locally hot temperatures are
expected, with the highest readings likely occurring early in the
forecast period due to anticipated southerly winds.


&&

.AVIATION...
(06Z TAFs)

VCTS psbl at TJSJ/TJBQ thru 05/12z. VFR conditions will prevail for
all TAF sites for most of the period. SHRA/TSRA is psbl in the
vicinity of TJBQ/TJSJ after 05/17z. Top obscr across the ctrl mtn
range of PR. A shearline will bring SHRA/TSRA at TJSJ/TJBQ/TIST
after 06/00z. Brief MVFR expected for these terminals, with ocnl IFR
or maybe worse. Winds shifting more ENE aft 05/16z btw 10-15kts, but
stronger, gustier winds near SHRA/TSRA, where winds may be VRB.


&&

.MARINE...

A surface high pressure building from the western to central
Atlantic will promote fresh to locally strong east to northeast
winds through midweek. Increased thunderstorm activity is expected
over the next few days. Increasing winds and pulses of northerly
swells will bring hazardous seas during the second half of the
week. Small craft advisories are now in effect for the offshore
Atlantic waters.


&&

.BEACH FORECAST...

Today, northern Puerto Rico beaches face a high risk of rip
currents, while a moderate risk is present for other north- and
east-facing beaches of Puerto Rico, Culebra, Vieques, and the U.S.
Virgin Islands. The overall risk is expected to decrease to
moderate tonight, but increasing winds will elevate the risk back
to high by Wednesday. For more details, please consult the Surf
Zone Forecast (SRFSJU).

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
452 AM AST Thu Nov 7 2024

.SYNOPSIS...
Unsettled weather is expected to persist over the next few days,
bringing frequent showers and strong thunderstorms. With soils
already saturated and elevated streamflows, flooding impacts are
likely. Boating and swimming are strongly discouraged today due to
hazardous seas, large breaking waves, and life-threatening rip
currents, with these conditions expected to persist through Friday.
Stay safe and stay informed! For a depiction of the areas at risk,
visit the Experimental Graphical Hazard Weather Outlook:
https://www.weather.gov/erh/ghwo?wfo=sju.

&&

.SHORT TERM...Today through Saturday...

Overnight radar and satellite analysis indicate an active night. The
first pulse, characterized by persistent light to moderate showers
and a few thunderstorms, faded around midnight. Since then, showers
and thunderstorms have redeveloped across the region, triggered by a
low-level induced low pressure that developed overnight from a
deepening upper-level trough, as indicated by satellite imagery and
TJUA NEXRAD's Vertical Azimuth Display (VAD) profile wind signature.
While surface observation reports recorded rainfall totals of up to
half an inch across northern and northeastern Puerto Rico since 8 PM
AST, radar-estimated accumulations in Culebra and Saint Thomas,
USVI, reached around three-quarters of an inch. Overnight
temperatures ranged from the lower 60s in higher elevations to
around 80 degrees across coastal observing stations of southern
Puerto Rico and the U.S. Virgin Islands. Winds were generally light
and variable, with higher gusts near the thunderstorms.
counterpart

Unsettled weather is anticipated to continue through much of the
short-term forecast period. Although the low-level induced low will
shift away from the region, its driving feature, an upper-level low,
will position itself favorably to the southwest today. In
combination with the upper low, a trough of low pressure, currently
monitored by the National Hurricane Center for tropical cyclone
formation, will move across the area through Friday, supporting an
influx of tropical moisture and promoting unstable conditions.
Satellite-derived precipitable water values suggest above-normal
November levels, fluctuating between 2.1 and 2.4 inches.
Consequently, frequent and strong thunderstorms are anticipated over
the next 24-48 hours, with high rain chances (70-90%) across all
land areas.

As the steering flow shifts from northeast to south-southeast
following the passage of the surface trough, rainfall will gradually
focus from eastern Puerto Rico today to southern Puerto Rico tonight
and into Friday, with the U.S. Virgin Islands also experiencing high
rain chances throughout this period. A weaker steering flow is also
expected to increase the likelihood of higher rainfall accumulations
from slow-moving showers. Given these conditions, an elevated to
significant risk of excessive rainfall exists today and Friday,
raising concerns for urban and small stream flooding, flash
flooding, river flooding, and mudslides across the region.
Additional hazards include frequent lightning and gusty winds
generated by thunderstorms, as well as breezy to locally windy
conditions along coastal areas. Despite the increased chance of rain
and cloudiness, southerly winds on Friday may lead to warmer
temperatures.

According to current model guidance, Saturday's weather pattern is
expected to be less stormy. East-southeasterly winds and daytime
heating will likely lead to more localized showers with isolated
thunderstorms, primarily in the afternoon. Flooding impacts are
likely to occur due to periods of moderate to locally heavy rainfall
over soils that are already saturated. Thunderstorm activity could
increase Saturday night as a tropical wave approaches the region.
For updates on excessive rainfall, lightning, and any other hazard
risk in the coming days, please visit the Experimental Graphical
Hazard Weather Outlook at https://www.weather.gov/erh/ghwo?wfo=sju.

.LONG TERM....Sunday through Thursday...

Some instability and a wet spell will prevail for the long-term
period across the region. By Sunday, tropical moisture from a
tropical wave now located several hundred east of the Lesser
Antilles will move south of the area. Although a significant
amount of moisture is associated with this tropical wave, so far
today, global model guidelines and The Gálvez-Davison Index (GDI)
suggest a scenario where the bulk of the moisture with showers and
scattered thunderstorms will remain just south of the islands only
affecting mostly southeastern section of Puerto Rico and the
Caribbean waters due to a rapid change in the surface winds from
the northeast in response of a broad building high pressure moving
eastward into the central Atlantic replacing the surface trough
located north of the region generated by the reflection of an
upper level low at the southwestern Caribbean. The east-northeast
wind flow will drag a slight area of drier air, limiting the
showers on Sunday afternoons somewhat for a brief period. East
winds return quickly as the board surface ridge moves more into
the central Atlantic, inducing the islands again for moisture
values above the climatological normals.

From Monday to Wednesday, the main weather feature will be a mid
to upper-level ridge providing stable conditions for the vertical
profile, inhibiting most of the shower development. Surface winds
will persist mainly from the east con, veering winds by Wednesday
into Thursday due to a low pressure developed over the western
Atlantic moving eastward into the Central Atlantic. This surface
change will increase the Relative Humidity % at 700-300 MB. There,
the islands can expect widespread showers and thunderstorms for
the last part of the upcoming workweek. There are some
discrepancies in the amount of moisture available from the two
global model guidance (ECMWF & GFS). However, both of them show a
wet pattern.

&&

.AVIATION...

(06Z TAFS) Increasing SHRA/TSRA across the region will likely result
in brief MVFR conditions, with BKN-OVC at FL015-025 and reduced
visibility. Light to calm and variable winds, becoming E-NE and
increasing to 10-15 knots between 07/14-22Z. Higher gusty winds are
expected near TSRA.

&&

.MARINE...

Recent data from the bouy network around the CWA shows seas
between 8 to 12 feet. A surface high pressure across the western
to central Atlantic and the proximity of a trough of low pressure
will promote fresh to locally northeasterly winds for today into
tonight. This wind-driven sea will combine with weak pulses of
long-period northeasterly swell along the area, resulting in
hazardous marine conditions. Small Craft Advisories are in effect
across most of the regional and local waters and passages through
at least Friday.

&&

.BEACH FORECAST...

Pulses of long-period wave energy arriving at the locally exposed
coastal areas and the high seas across the region will result in
large breaking waves up to 10 feet across all the northern coastal
areas of Puerto Rico, where a High Surf Advisory was issued this
morning until 6 PM this evening. For the western section of PR,
Culebra, Vieques, and the U.S. Virgin Islands, there is a high rip
current risk for the rest of the workweek in some of those points.
Please visit the Surf Zone Forecast (SRFSJU) for more related
information.