Caribbean - Central America Weather

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
534 AM AST Tue Nov 29 2022

.SYNOPSIS...A more seasonal and promising weather pattern will
persist throughout the workweek. A slight increase in moisture,
and thus, increased shower activity, is likely into early next
week due to the passage of occasional pockets of low- level
moisture from a fragmenting stationary front to the north of our
area. A long- period northeasterly swell spreading across the
Atlantic waters will deteriorate marine and coastal conditions
through at least Wednesday.

&&

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

An upper level high pressure to the west of the local islands, and
an upper low across the tropical Atlantic is causing relatively
stable conditions aloft with NW winds in the upper levels. A strong
high pressure at the surface across the northeastern US is moving
east and into the northwestern Atlantic, which is gradually causing
northeasterly winds across the local islands, which are expected to
continue for the next few days.

Brief isolated to scattered showers expected across the north and
eastern sections of PR, as well as portions of the USVI in the
morning hours. There is an area of deeper moisture that is moving in
from the north, which is causing some of these mostly light showers
to move into the local area in the morning. By the late morning
hours the shower activity is expected to mostly dissipate, and fair
weather is expected across most of the local islands. However, under
a northeasterly wind flow, combining with the available moisture and
diurnal heating, shower activity is expected to develop across the
southwest section of Puerto Rico this afternoon. The daytime high
temperatures are forecast in the mid to upper 80s across the lower
elevations, and in the mid 70s to low 80s across the higher
elevations.

The northeasterly wind flow is expected to continue through the
short term period. A somewhat similar weather pattern is then
expected for Wednesday, but with a quicker patch of moisture passing
through while most of the deeper moisture is expected to remain
across eastern PR and the USVI. Therefore, the scattered shower
activity is mainly expected to remain across the local waters, USVI,
and eastern PR, with only a slight chance of rain across western PR.
Then Thursday may be the driest day in the short term. The latest
guidance shows less moisture and very little rain. As far as
temperatures, the latest guidance is indicating near normal temps
today, in the mid to upper 80s across the lower elevations, while
the higher elevations will be in the mid 70s to near 80 degrees.
However, tomorrow and Thursday, the model is leaning slightly
cooler, with highs about 2-3 degrees cooler than today.

The arrival of a northerly long-period swell is causing hazardous
seas and surf zone conditions. Therefore a small craft advisory
and a high surf advisory are both in effect. There is also a high
risk of rip currents.

&&

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

Fair weather conditions and seasonal weather patterns are still
expected to prevail through at least Saturday. Latest model run
shows ridging and dry air dominating the area during that period
limiting the potential for moderate and heavy rainfall.
Nevertheless, patches of moisture, with normal to below-normal
precipitable water values, will still filter into the local
islands from time to time. For most long-term forecasts, the wind
flow will be out of the northeast. During the morning, expect
showers to move across the northeastern quadrant of Puerto Rico
and the U.S. Virgin Islands. In the afternoon, expect showers to
move across the southwestern quadrant of Puerto Rico.

Model guidance suggests increasing moisture content at the surface
and mid-levels by Sunday night as a frontal boundary reaches the
area. At this time, PWAT models show up to and below 1.5 inches of
rain from Sunday night to Monday. Nevertheless, expect some
moisture to linger across the area through the remaining forecast
period, but overall expect the typical weather pattern to return
gradually.

&&

.AVIATION...VFR conditions will prevail across the forecast
period. However, brief -SHRA/SHRA will affect TJSJ/TJBQ/IST/ISX
through around 29/14Z. SHRA will develop over the southwestern
sections of PR after 29/17Z, which could cause VCSH at TJPS. Winds
will be calm to light/VRB through 29/13Z, thereafter, from the NE
at 10-15 kt with occasional gusts and sea breeze variations.

&&

.MARINE...A long period northerly swell will continue to build
today across the Atlantic waters and passages. Seas are currently
forecast to range between 5 and 7 feet. Therefore, a Small Craft
Advisory is in effect for the Atlantic waters and the Mona
Passage. This swell will also cause high surf conditions with
life-threatening rip currents along the Atlantic beaches of Puerto
Rico, Rincon, Culebra, and St. Thomas.

&&

.SJU WATCHES/WARNINGS/ADVISORIES...
PR...High Rip Current Risk through late Wednesday night for PRZ001-
002-005-008-010-012.

High Surf Advisory until 6 AM AST Wednesday for PRZ001-002-005-
008-012.

High Surf Advisory until 8 PM AST this evening for PRZ010.

VI...High Rip Current Risk through late Wednesday night for VIZ001.

High Surf Advisory until 6 AM AST Wednesday for VIZ001.

&&

$$

SHORT TERM...JA
LONG TERM....MMC
AVIATION...JA

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
510 AM AST Wed Nov 30 2022

.SYNOPSIS...Today, expect brief showers in the morning across
eastern-northeastern Puerto Rico and scattered showers across
southwestern PR in the afternoon. Nevertheless, a seasonal and
promising weather pattern will persist throughout the workweek. A
dissipating long- period northeasterly swell and increasing winds
will generate choppy marine conditions and life-threatening rip
currents through at least Thursday.

&&

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

An upper level high pressure across the western Caribbean, and an
upper low across the central Atlantic extending a trough to the east
of the local islands is causing subsidence and W-NW winds in the
upper levels. A strong high pressure at the surface across the
northwestern Atlantic is causing northeasterly winds across the
local islands today, then another surface high pressure will move
over the eastern US and into the western Atlantic, maintaining the
NE winds across the local area through the end of the week.

Patches of moisture will be moving through the local area for the
next few days. However, the latest guidance favors the moisture to
move in later in the afternoon into the night time hours today and
tomorrow, while Friday may have a patch of moisture during the day.

Brief isolated to scattered showers expected across the north and
eastern sections of PR, as well as portions of the USVI this
morning. By the late morning hours the shower activity is expected
to mostly dissipate, and fair weather is expected across most of the
local islands. However, under the persistent northeasterly wind
flow, combining with the local effects, shower activity is expected
to develop across the southwest section of Puerto Rico this
afternoon, while another round of scattered showers is forecast for
the USVI. The daytime high temperatures are forecast in the mid 80s
across the lower elevations, and in the mid 70s to low 80s across
the higher elevations.

The patch of moisture for Thursday will move later in the afternoon
than today, causing mainly fair weather during the daytime hours,
but scattered showers are forecast early in the morning and then in
the evening hours for north and eastern PR and across the USVI.
Friday will also have the morning showers across north and eastern
PR and the USVI, but it will also have afternoon showers across the
southwestern portions of PR and across other areas in SE PR and the
USVI. As far as temperatures, the latest guidance continues to
indicate slightly cooler, with highs about 1-2 degrees cooler than
normal.

&&

.LONG TERM...Saturday through Thursday...

On Saturday, expect fair weather conditions and seasonal weather
patterns to prevail. During this time, ridging and dry air will be
present, limiting the potential for moderate and heavy rainfall.
Still, patches of moisture, with normal to below-normal
precipitable water values, will filter into the local islands from
time to time. The wind flow will remain out of the northeast for
most long-term forecasts. Therefore, expect showers to move across
the northeastern quadrant of Puerto Rico and the U.S. Virgin
Islands in the morning. In the afternoon, expect showers to move
across the southwestern quadrant of Puerto Rico.

The latest guidance suggests increasing moisture content at the
surface and mid-levels by Sunday night as a frontal boundary reaches
the area. The PWAT models show up to and below 1.5 inches of rain
from Sunday night to Monday. Nevertheless, expect some moisture
to linger across the region through the remaining forecast period,
but overall expect the typical weather pattern to return gradually
as a ridge at all levels positions across the area.

&&

.AVIATION...VFR conditions will prevail across the forecast period.
However, VCSH is possible during the day across the local
terminals, though the better chance for VCSH is before 30/15Z and
after 30/20Z. Winds will be from the NE at 10-15 knots with
occasional gusts and sea breeze variations.

&&

.MARINE...Coastal buoys from San Juan to Rincon were indicating
seas at 4 feet, and northeasterly winds. The northerly swell will
continue to slowly subside through Wednesday and a high rip
current risk remains in effect for the Atlantic beaches of Puerto
Rico, and Culebra. Elsewhere, a moderate risk prevails.

&&

.SJU WATCHES/WARNINGS/ADVISORIES...
PR...High Rip Current Risk through Thursday afternoon for PRZ001-002-
005-008-012.

High Rip Current Risk until 6 AM AST early this morning for
PRZ010.

VI...None.

&&

$$

SHORT TERM...JA
LONG TERM....MMC
AVIATION...JA

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
512 AM AST Thu Dec 1 2022

.SYNOPSIS...Today, expect early morning passing showers. Afternoon
convection is possible, but with limited impacts. Despite this, a
seasonal and promising weather pattern will persist throughout
the workweek. A dissipating long-period northeasterly swell and
increasing winds will generate choppy marine conditions and life-
threatening rip currents during the next few days.

&&

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

An upper level high pressure across the western Caribbean, and an
upper low across the central Atlantic with a trough to the east of
the local islands is causing subsidence and W-NW winds in the upper
levels through Friday. On Saturday, an upper trough may be
developing over the local islands, causing stronger winds aloft and
some instability, possibly causing locally numerous showers
overnight from Friday into Saturday. A weakening high pressure at
the surface across the western Atlantic and a strong surface high
pressure across the eastern US will cause northeasterly winds across
the local islands through the short term period, as the
aforementioned high pressure across the eastern US moves east and
into the western Atlantic.

Patches of moisture will continue moving through the local area for
the next few days. The latest guidance continues to favor the deeper
moisture to move out of the local area by the mid morning hours
today, but will return during the day on Friday. On Saturday, the
deeper moisture could be across western and eastern PR as well as
over the USVI, but slightly drier air may be present over most of PR.

Brief scattered to locally numerous showers are expected across the
north and eastern sections of PR, as well as portions of the USVI
this morning. By the late morning hours the shower activity is
expected to mostly dissipate, and fair weather is expected across
most of the local islands. However, under the persistent
northeasterly wind flow, combining with the local effects, shower
activity is expected to develop across the southwest section of
Puerto Rico this afternoon, while another round of scattered showers
is forecast for the USVI. Essentially a very similar pattern to what
was observed yesterday. The weather pattern for Friday will be once
again similar to today with morning scattered showers across the
USVI and eastern PR, while afternoon showers will develop across SW-
PR. Late Friday into Saturday morning, scattered to locally numerous
showers are forecast across northern and eastern PR, then afternoon
scattered showers across SW-PR.

The daytime high temperatures are forecast in the mid 80s across the
lower elevations, and in the mid 70s to low 80s across the higher
elevations.

&&

.LONG TERM...Sunday through Friday...

Model guidance continues to suggest an increase in moisture
content at the surface and mid-levels by Sunday night as a
frontal boundary reaches the area. During that period, a trough at
all levels will position across the region. Latest PWAT models
show up to and below 1.5 inches of rain during this event. On
Tuesday, expect some moisture to linger across the area. By mid-
week, mostly fair weather conditions and seasonal weather patterns
will prevail. During this time, a ridge at all levels will
position across the forecast area, limiting the potential for
significant rainfall. Nevertheless, patches of moisture, with
normal to below-normal precipitable water values, will
occasionally filter into the local islands. The wind flow will
remain out of the northeast for most long-term forecast.
Therefore, in the morning, expect showers to move across the
northeastern quadrant of Puerto Rico and the U.S. Virgin Islands.
In the afternoon, expect showers to move across the southwestern
quadrant of Puerto Rico.

&&

.AVIATION...VFR conditions will prevail across the forecast period.
However, SCT-SHRA will cause VCSH during the day across the local
terminals, though the better chance for VCSH is before 01/15Z and
after 01/20Z. Winds will be from the NE at 10-15 knots with
occasional gusts and sea breeze variations.

&&

.MARINE...Coastal buoys across the surrounding waters of PR and
the USVI were indicating seas between 3-5 feet, and northeasterly
winds. The northerly swell will continue to slowly fade today,
but increasing winds will maintain choppy seas across portions of
the local waters through the workweek. A high rip current risk
remains in effect for the Atlantic beaches of Puerto Rico, and for
Culebra until 6 AM. Elsewhere, a moderate risk prevails.

A larger northerly swell is expected to move across the Atlantic
waters and passages during the weekend, hazardous seas and coastal
conditions are expected.

&&

.SJU WATCHES/WARNINGS/ADVISORIES...
PR...High Rip Current Risk through this afternoon for PRZ001-005-008.

High Rip Current Risk until 6 AM AST early this morning for
PRZ002-012.

VI...None.
&&

$$

SHORT TERM...JA
LONG TERM....MMC
AVIATION...JA

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
502 AM AST Fri Dec 2 2022

.SYNOPSIS...Today, expect a seasonal pattern. A surface high
pressure will promote a northeasterly wind pattern for the short
term period. Some patches of moisture embedded in the wind
pattern, will filter into the region today, resulting in passing
showers in the morning and afternoon hours. Choppy marine
conditions will persist until today due to moderate to locally
fresh winds. Hazardous marine conditions are forecast for the
upcoming weekend with the arrival of a northeasterly long period
swell.

&&

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

An upper level high pressure across the western Caribbean, and an
upper low across the central tropical Atlantic continues to cause
some subsidence and W-NW winds in the upper levels today. On
Saturday and Sunday, an upper trough will develop over the local
islands, causing stronger winds aloft and some instability, which
may slightly increase the shower activity, yet still brief over any
one area late tonight into Saturday. A surface high pressure across
the eastern US and a surface low to the east of the local islands
will cause northeasterly winds across the local islands through
Saturday, but then northerly on Sunday.

Patches of moisture will continue moving through the local area for
the next few days. The patch with the deepest moisture is expected
on Saturday according to the GFS model. The latest guidance suggests
that the moisture on Saturday will encompass most of the local
islands, but the impact should still be modest, with scattered
showers across the local area.

Brief scattered to locally numerous showers are expected across the
north and eastern sections of PR, as well as portions of the USVI
this morning. Once again, by the late morning hours the shower
activity is expected to diminish, leaving mainly isolated showers.
However, under the northeasterly wind flow, combining with the local
effects, shower activity is expected to develop across the southwest
section of Puerto Rico this afternoon, while scattered showers are
also forecast for parts of the interior of PR. The weather pattern
for Saturday will be once again similar to today with morning
scattered showers across the USVI and eastern PR, while afternoon
showers will develop across SW-PR late in the afternoon. Sunday
looks like a drier day overall, the available moisture will be the
lowest in the short term period, and the wind will be from the
north.

The daytime high temperatures are forecast in the low to mid 80s
across the lower elevations due to the northeasterly to northerly
winds, and in the low to upper 70s across the higher elevations.

-A personal note. My name is Jose "Jay" Alamo, I have proudly been a
meteorologist at the San Juan WFO for over 14 years, serving the
people of Puerto Rico and the U.S. Virgin Islands. In those 14 years
we have worked with many things, from wonderful and beautiful days
where we told you to enjoy the beautiful day, to asking you to
prepare for a devastating hurricane. It has been quite an amazing
ride, surrounded by wonderful, professional, talented, and hard
working co-workers. Today is my last day with the San Juan office,
as the next chapter in my career takes me to College Park, MD to
become the International Desks Chief at the NWS Weather Prediction
Center. It has been a pleasure serving you all, I will miss
everything about this job, it has taken me to amazing places and I
have met wonderful people. Thank you for the opportunity to serve
you. I hope you all have a wonderful holiday season. Jay

&&

.LONG TERM...Monday through Saturday...

Latest guidance continues to suggest an increase in moisture at the
surface and a slight increase at the 700mb level. The increase in
moisture during the first part of the workweek is mainly due to a
frontal boundary across the forecast area. On Monday, expect the
favorable side of a trough at all levels to move through the
region, improving the potential for rainfall activity. A northerly
wind flow will prevail throughout the long term as a surface low
and a high-pressure system in the Atlantic position near the area.
On Tuesday, expect lingering moisture to move through the local
islands.

By midweek, a more seasonal pattern and fair weather conditions are
forecast as a ridge at all levels positions across the forecast
area, limiting the potential for significant rainfall.
Nevertheless, patches of moisture, with normal to below-normal
precipitable water values, will occasionally filter into the
islands. The prevailing northeasterly wind flow will cause the
morning showers to develop across the northeastern quadrant of
Puerto Rico and the U.S. Virgin Islands and the afternoon showers
to move across the southwestern quadrant of Puerto Rico. The
seasonal pattern is expected to remain through Saturday.

&&

.AVIATION...VFR conditions will prevail across the forecast
period. However, SCT-SHRA will cause VCSH during the day across
the local terminals, though the better chance for VCSH is before
02/15Z and after 02/20Z. Winds will be from the NE at 10-15 knots
with occasional gusts and sea breeze variations.

&&

.MARINE...Expect choppy seas between 3 and 5 feet with occasional
seas up to 6 feet due to a moderate to locally fresh northeasterly
wind flow. Another long period northeasterly swell, will reach
the local Atlantic waters and Caribbean passages by late Friday
night or early Saturday morning into early next week, deteriorating
marine and coastal conditions.

&&

.SJU WATCHES/WARNINGS/ADVISORIES...
PR...None.
VI...None.
&&

$$

SHORT TERM...JA
LONG TERM....MMC
AVIATION...JA

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
445 AM AST Sun Dec 4 2022

.SYNOPSIS...
Patchy moisture is supporting a seasonal weather pattern of
passing showers for the next couple days. Northerly winds will
strengthen overnight, increasing the frequency of showers that
will reach PR and The USVI. Overall, flooding impacts are not
anticipated, but there is still a risk of water ponding on
roadways and poorly drained areas causing hazardous driving
conditions.

A northeasterly swell has arrived over the last 12 hours and is
expected to peak tonight. As a result, hazardous marine and
coastal conditions will prevail for the next several days,
including seas and breaking wave heights in excess of 10 feet. See
the Marine section below for more details.

&&

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

Short-term dominant features are an elongated surface high
pressure extending southwestward from the north-central into the
western Atlantic, a developing mid-to-upper level low and surface-
induced feature with the associated trough's axis extending
southwestward into the northeastern Caribbean region, and a long-
period northeasterly swell spreading across the Atlantic waters
and local Caribbean passages. These features will maintain hazard
risk at limited to significant or high levels for rip currents,
marine conditions, thunderstorms, and winds throughout the cycle.

Today's timeline will begin with a shallow patch of moisture,
identified in radar and satellite imagery by scattered to locally
numerous showers and a few isolated thunderstorms, crossing the
local islands under a northerly wind flow through the early
morning hours. Rainfall accumulations from this activity could
lead to ponding of water on roadways and poorly drained areas,
mainly across coastal municipalities of northeastern Puerto Rico.
Localized urban and small stream flooding is possible, but chances
are limited. After that, a pocket of drier air will reach the
islands late this morning, limiting any opportunity for widespread
showers while supporting more seasonal weather conditions with a
mixture of sunshine and passing showers embedded in the northerly
trade wind flow through this evening. Under the dominant northerly
flow at 10 to 15 mph with higher gust and sea breeze variations,
expect slightly cooler daytime maximum temperatures ranging from
the mid 80s across coastal areas to lower 70s across higher
elevations.

For tonight and continuing through Tuesday, as the surface-
induced low gradually builds northeast of the region and the
pressure gradient tightens, expect an increase in wind speeds of
around 15-25 mph, causing more frequent patches of low-level
moisture to reach the local islands and, thus, an increase in
shower activity. This activity will favor the northern half and
portions of the interior of Puerto Rico, Vieques, Culebra, and the
U.S. Virgin Islands. Showers may even move further inland as wind
speeds increase. Showers are expected around the clock, but more
frequent showers are likely at nighttime when the influence of
advective cooling processes is more significant, and precipitable
water vapor values are at their highest concentrations of around
1.5 inches. Uncertainties on isolated thunderstorm development are
present. While the exclusion of thunderstorms on the official
forecast is explicit, one or two could develop due to some
instability generated by the upper-level trough. Overall, flooding
impacts are not anticipated, but there is still a risk of water
ponding on roadways and poorly drained areas causing hazardous
driving conditions. Slightly cooler daytime maximum and minimum
temperatures are expected each day, falling as low as the mid to
upper 50s across higher elevations during the clearest nights.

&&

.LONG TERM...Wednesday through Monday...

A dry, breezy northeasterly flow will prevail on Wednesday and
Thursday due to cool air advection as a deep trough in the Central
Atlantic remains the predominant feature. Rainfall should be
limited during this time due to patchy moisture and at times low
precipitable water values. By Friday, local winds begin to lighten
into the weekend as the trough moves further east into the
Atlantic Basin. Weak concentrations of moisture continue to
dominate during this period, therefore no significant rainfall is
forecast. During these days, the most shower activity is expected
across northern and eastern sections due to passing windward
showers. There is a chance each afternoon for convection to form
over land, potentially providing rain to the interior and southern
sections of Puerto Rico.

By Sunday, another trough will begin crossing the Western
Atlantic and there will be an area of high pressure at the
surface in the Gulf of Mexico, together providing an irregular
windflow, light and variable from the west. The end of the period
remains quite dry with a continuation of patchy to drier moisture
values. Confidence on the exact location of rainfall is low at
the moment, however no significant amounts are expected. Marine
models suggest that these low pressure systems will be significant
swell producers, therefore the greatest hazards will be found
across the coastal and marine zones during this time.

&&

.AVIATION...Mainly VFR conditions will prevail across all local
terminals through the cycle. Increased trade wind SHRA may result
in brief MVFR conditions at TJSJ, TJBQ, and TIST throughout the
day, with a few TSRA bringing VCTS through 04/14Z. Light and
variable winds across all PR terminals and light northeasterly
winds at USVI terminals will prevail through 04/14Z. Winds will
remain from the north and increase to 10-15 knots with higher
gusts and sea breeze variations after 04/14Z.

&&

.MARINE... Currently observed across the regional waters is a
northeasterly swell between 6 and 8 feet with a period ranging
between 10 and 11 seconds. Seas will increase even more today and
over the next few days, therefore Small Craft Advisories are in
effect for most of the Atlantic Waters and Caribbean Passages. The
long- period northeasterly swell will peak late tonight, lasting
into Tuesday with heights around 10 feet, with occasional seas up
to 13 feet, and periods around 11 seconds. Another long-period
northeasterly swell will reach the local Atlantic waters from
Thursday onward.

PR's beachgoers, A High Surf Advisory and a high risk of rip
currents also remain in effect due to expected breaking waves
around 6 to 12 feet, mainly across north-facing beaches of Puerto
Rico and Culebra.

USVI's beachgoers, a high risk of life-threatening rip currents
remains is in effect for most local waters.

&&

.SJU WATCHES/WARNINGS/ADVISORIES...
PR...High Rip Current Risk through Tuesday afternoon for PRZ001-002-
005-008-010-012.

High Surf Advisory until 6 AM AST Tuesday for PRZ001-005-008.

High Surf Advisory until 6 AM AST Tuesday for PRZ002-010.

High Surf Advisory from 6 PM this evening to 6 AM AST Tuesday
for PRZ012.

High Rip Current Risk from this evening through Tuesday
afternoon for PRZ013.

VI...High Rip Current Risk from this evening through Tuesday
afternoon for VIZ002.

High Rip Current Risk through Tuesday afternoon for VIZ001.

.AM...Small Craft Advisory until 8 PM AST Tuesday for Atlantic
Waters of Puerto Rico and USVI from 10 NM to 19.5N-Coastal
Waters of Northern Puerto Rico out 10 NM-Mona Passage
Southward to 17N-Coastal Waters of Northwestern Puerto Rico
out 10 NM.

Small Craft Advisory from 8 AM this morning to 8 PM AST
Tuesday for Coastal Waters of Northern USVI and Culebra
out 10 NM.

Small Craft Advisory from 8 PM this evening to 8 AM AST
Tuesday for Anegada Passage Southward to 17N-Coastal Waters
of Southern USVI Vieques and Eastern Puerto Rico out 10 NM.

&&

$$

SHORT TERM...ICP
LONG TERM....RC

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
458 AM AST Tue Dec 6 2022

.SYNOPSIS...
Passing showers from the Atlantic waters will continue to move
into the northern half of Puerto Rico and the northern U.S.
Virgin Islands as breezy northerly winds prevail. Elsewhere,
expect a more seasonal pattern characterized by a mixture of
sunshine and passing showers. Slightly cooler daytime
temperatures are expected each day, ranging from the mid 80s
across lower elevations at daytime to mid 50s across higher
elevations at nighttime. Expect a similar pattern to continue for
the next week.

A northeasterly swell continues to invade the local waters,
causing hazardous coastal and marine conditions. Small Craft
Advisories are in effect for most of the local waters and also a
High Surf Advisory and a High Risk of Rip Currents statement is
also active for most of the local beaches. See the Marine section
for more details.

&&

SHORT TERM...Today through Thursday...

Short-term dominant features are a mid-to-upper level low and
surface-induced feature to the northeast, which will slowly move
northeastward and away from the area. The associated trough axis
extends southwestward into the northeastern Caribbean region,
generating some instability. The surface-induced low, currently
monitored by the National Hurricane Center for potential subtropical
or tropical development, combined with a building high pressure
moving into the western Atlantic, will continue to yield northerly
winds through the cycle. Lastly, a long-period northeasterly swell
spreading across the Atlantic waters and local passages into the
Caribbean Sea remains the dominant feature for marine conditions.
These features maintain hazard risk levels elevated to high or
significant for rip currents, marine conditions, and winds
throughout the cycle.

Local weather conditions will continue to be dominated by shallow
patches of moisture embedded in the general northerly flow, carrying
showers from the Atlantic waters into the northern half of Puerto
Rico, the northern U.S. Virgin Islands, and the local islands.
Although winds will gradually subside to 10-15 mph with the
relaxation of the local pressure gradient, pushing less frequent
showers inland, ponding of water on roadways and poorly drained
areas is still likely, mainly across northern Puerto Rico.
Elsewhere, expect a more seasonal pattern characterized by a mixture
of sunshine and passing showers producing minimal impacts. A similar
weather pattern will persist on Wednesday and Thursday but with even
less frequent trade wind showers as wind speeds continue to subside
and pockets of drier air move into the area. With a predominantly
northerly component in the general wind flow, slightly cooler
daytime temperatures than climatology are expected each day, ranging
from the mid 80s across lower elevations at daytime to mid 50s
across higher elevations at nighttime. Brief gusty conditions are
possible accompanying the passing showers.

&&

.LONG TERM...Friday though Wednesday...

A large area of low pressure in the Central Atlantic, that is moving
to the northeast towards Europe, will maintain the ongoing
weather pattern. This will consist of a generally northerly wind
flow with average to below-average moisture for most of the long
term period. Low level wind direction will shift from a breezy
northeasterly flow on Friday to potentially a gentle north-
northwesterly flow on Sunday as another area of low pressure at
the surface works it's way into the Western Atlantic. This will
yield a regime of scattered passing showers moving in from the
north to affect Puerto Rico and the northern USVI, providing brief
rainfall that will not pose much of a flooding threat. There
perhaps may be an increase of shower activity by next Tuesday as
an upper level jet from a ridge spread across the Caribbean
combines with building trade winds and slightly higher moisture.
Seasonal cooler air temperatures due to these northerly winds
will continue throughout this time.

&&

.AVIATION...Mainly VFR conditions will prevail across most
local terminals during the next 24 hours. SHRA could result in brief
MVFR conditions at TJSJ, TJBQ, and TIST throughout the day. Lesser
SHRA will affect the remaining airports, but brief MVFR conditions
are still possible. N-NE winds will persist at 10-15 knots with
higher gusts. Locally higher winds are possible near the shower
activity.

&&

.MARINE...Coastal and marine conditions will continue to be
hazardous due to a northeasterly swell that CARICOOS's San Juan
Buoy is currently detecting to have a significant wave height of
8.1 ft with a period of 11.1 seconds. Expect seas up to 10 feet
across northern exposed waters for the next couple days. Another
powerful northeasterly swell is expected to arrive on Friday
morning, continuing this trend of hazardous conditions.

Small Craft Advisories are in effect for most of the local waters,
with the exception of the Coastal Waters of Southwestern Puerto
Rico out 10 NM and the Coastal Waters of Southern Puerto Rico out
10 NM.

A High Surf Advisory and a High Risk of Rip Currents statement also
remain in effect due to expected breaking waves around 6 to 13
feet, mainly across north-facing beaches of Puerto Rico, Culebra
and the northern USVI. Also, Vieques's and St. Croix's northern
and eastern beaches have a High Risk of Rip Currents.

&&

.SJU WATCHES/WARNINGS/ADVISORIES...
PR...High Rip Current Risk through Thursday afternoon for PRZ001-002-
005-008-010-012-013.

High Surf Advisory until 6 AM AST Thursday for PRZ001-002-005-
008-012.

High Surf Advisory until 6 PM AST Wednesday for PRZ010.

VI...High Rip Current Risk through Thursday afternoon for VIZ001-002.

High Surf Advisory until 6 PM AST this evening for VIZ001.


AM...Small Craft Advisory until 8 AM AST Friday for Coastal
Waters of Southern USVI Vieques and Eastern Puerto Rico out 10
NM, Caribbean Waters of Puerto Rico from 10 NM to 17N.

Small Craft Advisory until 8 AM AST Friday for Atlantic Waters
of Puerto Rico and USVI from 10 NM to 19.5N, Coastal Waters of
Northern Puerto Rico out 10 NM-Mona Passage Southward to
17N,Coastal Waters of Northwestern Puerto Rico out 10 NM, Coastal
Waters of Northern USVI and Culebra out 10 NM, Anegada Passage
Southward to 17N.

&&

$$

SHORT TERM...ICP
LONG TERM...RC

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
510 AM AST Wed Dec 7 2022

.SYNOPSIS...
A low pressure system in the Central Atlantic will continue to
yield a continued pattern of breezy northerly winds and passing
showers until mid-next week when easterly trade winds will return,
resulting in a more familiar weather pattern of passing showers
across eastern sections followed by afternoon convection.

Marine and Coastal conditions will remain hazardous at least for
the next week from a barrage of northerly swells. These
high seas will keep most of the local waters in Small Craft
Advisory criteria. High Surf Advisories and High Rip Current Risk
statements are also in effect due to breaking wave heights in
excess of 10 feet.

&&

SHORT TERM...Today through Friday...

Short-term's story focuses on long-period northeasterly swells
spreading across the Atlantic waters and Caribbean passages. These
features will maintain marine conditions and rip currents hazards
between elevated to significant or high risk levels during the
next few days. Please refer to the Marine Discussion below for
details, including current statements and advisories.

Regarding weather-related dominant features, a northeastward moving
mid-to-upper level low and surface-induced feature over the central
subtropical Atlantic and a high pressure system moving eastward into
the western Atlantic will continue to yield northerly winds at 10-20
mph through the cycle. However, winds are forecast to diminish and
become more northeasterly from Friday onwards as the local pressure
gradient relaxes while both features continue to move further
eastward. Aloft, the associated trough, extending southwestward into
the northeastern Caribbean, will continue to generate some
instability.

Local weather conditions will continue to be dominated by
intermittent patches of drier air and shallow moisture embedded in
the general northerly flow. For today and tonight, relatively drier
air will gradually encompass the region, supporting generally fair
weather conditions with less and less frequent passing showers
moving inland from the waters. After that, the entrance of
additional pockets of drier air will lead to similar conditions by
Thursday afternoon and Friday evening, when precipitable water vapor
levels may fall below an inch. In contrast, expect an increase in
passing showers with shallow patches of moisture, mainly around
Thursday afternoon and Friday night. Any shower activity will favor
the northern half of Puerto Rico, the northern U.S. Virgin Islands,
and the local islands. Slightly cooler daytime temperatures than
climatology will continue each day, ranging from the mid 80s across
lower elevations during the day to mid 50s across higher elevations
at nighttime. Brief gusty conditions are possible accompanying the
passing showers.


&&

.LONG TERM...Saturday through Thursday...

A polar trough in the Western Atlantic will reflect low pressure
down to the surface, maintaining a gentle northerly flow across
the local region through Monday. Meanwhile, climatologically
average to slightly drier precipitable water is expected to hold
up scattered to isolated passing showers, driven by these
northerly winds. This is a continuation of the weather that is
being currently experienced; widespread, light rain without much a
concern for flooding.

On Tuesday, possibly an area of high pressure will manage to form
on the southern flank of the constant back to back lows pressure
systems, allowing an easterly trade wind flow to return for the
first time in over a week. GFS guidance is even hinting at a
southerly component in the flow throughout Tuesday, possibly
delivering moist air from the south until the end of the week.
During this time upper level winds start to accelerate across the
Caribbean, which could enhance lower level atmospheric
instability. In summary, a continued pattern of northerly winds
and passing showers is expected until mid-next week when easterly
trade winds will return, resulting in a more familiar pattern of
passing showers across eastern sections followed by afternoon
convection.

&&

.AVIATION...Mainly VFR conditions will prevail across most local
terminals during the next 24 hours. Passing SHRA could result in
brief MVFR conditions at TJSJ, TJBQ, and TIST throughout the day.
Lesser SHRA will affect the remaining airports, but brief MVFR
conditions are still possible. N-NE winds at 5-10 knots will
increase to 10-15 knots after 07/14Z and to 10-20 knots after 07/22Z
with higher gusts, mainly across northern terminals. Locally higher
winds are possible near the shower activity.

&&

.MARINE...
Hazardous marine conditions will persist for the next week as a
northerly swell continues to invade the local waters and then as
another strong northeasterly swell arrives on Thursday night,
lasting throughout the weekend, into next week. These conditions
will keep most of the local waters in Small Craft Advisory
criteria, with seas well above 7 feet for most zones, reaching up
to 15 feet during the next swell. Only the waters of the southern
and southwestern coast of Puerto Rico are not under a Small Craft
Advisory due to more tranquil conditions.

High Surf Advisories and High Rip Current Risk statements are in
effect due to expected breaking waves around 6 to 13 feet mainly
across north-facing beaches of Puerto Rico, Culebra and the USVI.
Breaking wave heights are expected to reach up around 16 feet with
the next swell, therefore these hazards will be relevant for the
next several days.


.Prev discussion.../issued at 525 PM AST Tue Dec 6 2022/

&&

.SJU WATCHES/WARNINGS/ADVISORIES...
PR...High Rip Current Risk through Saturday afternoon for PRZ001-002-
005-008-010-012-013.

High Surf Advisory until 6 PM AST Saturday for PRZ001-002-005-
008-012.

High Surf Advisory until 6 AM AST Thursday for PRZ010.

VI...High Rip Current Risk through Saturday afternoon for VIZ001-002.

High Surf Advisory until 6 AM AST Thursday for VIZ001-002.

AM...Small Craft Advisory until 8 AM AST Friday for Coastal
Waters of Southern USVI Vieques and Eastern Puerto Rico out 10
NM, Caribbean Waters of Puerto Rico from 10 NM to 17N.

Small Craft Advisory until 8 AM AST Friday for Atlantic Waters
of Puerto Rico and USVI from 10 NM to 19.5N, Coastal Waters of
Northern Puerto Rico out 10 NM-Mona Passage Southward to 17N,
Coastal Waters of Northwestern Puerto Rico out 10 NM, Coastal
Waters of Northern USVI and Culebra out 10 NM, Anegada Passage
Southward to 17N.

&&

$$

SHORT TERM...ICP
LONG TERM...RC

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
515 AM AST Thu Dec 8 2022

.SYNOPSIS...
A seasonal pattern prevails with frequent passing showers carried by
northerly winds. Expect similar conditions during the next
several days. Hazardous marine and coastal conditions will prevail
all week into the upcoming weekend.

&&

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

Our focus continues to be on the marine situation as the most
critical part of the weather story. Northeasterly swells with
11-12 second periods will spread across the Atlantic waters today
and the Caribbean passages tonight. Please refer to the Marine
Discussion below for details, including current statements and
advisories.

Northerly flow of 10 to 20 mph will continue to be generated by the
gradient at low and mid levels between high pressure over the
northern Gulf of Mexico and a very strong low pressure almost 1300
miles northeast with a trough that extends across the southeast
quadrant of our forecast area. This low will move another 1300
miles northeast during the next 3 days. A second low may also
develop along a cold front in the western Atlantic and move toward
the area with the combined northerly flow driving a cold front
toward the area. By late Saturday night that cold front will
likely have entered our northern waters. Showers are expected to
continue in the northerly flow during the night and morning hours
along the northern coast of Puerto Rico and the northern U.S.
Virgin Islands with light amounts each day. Very dry air will
remain in place over the area above 8-10 kft and this will cap the
showers and suppress rain amounts. Thus, although showers will be
frequent and mainly during the overnight and morning hours along
the coastal regions, amounts should remain less than one tenth to
one half inch in isolated spots each day. Because of the northerly
flow, cool air advection will prevail and help to keep
temperatures a degree or two below normal for this time of year
except along the south coastal plains.

An upper level trough will also move through today, but the ridge to
our west will flatten out and a second trough will take its place
and cross through the area on Saturday. This will leave us in a
quiet area of the upper atmosphere between a 100-plus knot
subtropical jet to our north and a much weaker jet over the
Windward Islands.

&&

.LONG TERM...Sunday through Friday...

A surface high pressure will remain over the Gulf of Mexico
through Tuesday, allowing northerly wind flow over the Caribbean.
This wind flow will keep overall drier conditions across the
forecast areas. However, on Sunday, cold advection from a frontal
boundary reaching the islands could increase the potential for
more frequent showers and even scattered to numerous showers
across the northern coastal areas. As this band of moisture moves
past us, a drier airmass will filter into the region Tuesday
through Thursday, resulting in mostly clear skies punctuated by
mainly isolated showers.

On Tuesday, as the ridge moves more to the northeast into the
east coast of the United States, a relaxation in the pressure
gradient will permit lighter winds across the islands and a
slight veering to the east- northeast. This change will allow
some bands of moisture to reach the Caribbean waters, St. Croix,
and the southern sections of Puerto Rico. Therefore, expect an
increase in the frequency of the showers from late Wednesday into
late Thursday there. Regardless of the expected conditions, the
rest of the islands, including St. Thomas, should expect mainly
fair weather conditions. Surface winds will come back from the
north late Thursday into Friday as the surface high pressure moves
into the central Atlantic.

Below normal temperatures will prevail for the first part of the
period, with even lower temperatures on Monday into Tuesday.

&&

.AVIATION...Mainly VFR conditions will prevail across most local
terminals during the next 24 hours. Passing SHRA could result in
brief mtn obscurations and MVFR conditions thru 08/16Z. N-NE winds
at 5-10 knots will increase to 10-15 knots after 08/14Z with
higher gusts, mainly across northern terminals. Locally higher
winds will be found near the shower activity. Maximum winds WSW-
WNW 55-65 knots btwn FL435-510.


.MARINE...

Hazardous marine conditions will prevail for the rest of the
period due to a northeasterly swell. For today expect seas around
8-9 feet in the morning, then building seas between 9 to 12 feet
are expected for most of the Atlantic waters and the local
passages starting tonight. Advisories are in effect for those
waters for conditions dangerous to the navigation of small craft.
Breaking waves up to 15 feet will cause dangerous rip currents,
beach erosion and local coastal flooding conditions across the
islands' northern and eastern sections. High Surf Advisories are
in effect as well as statements for a high rip current risk.

Breaking waves will are expected to increase to 16-17 feet;
please stay tuned for further updates and a possible coastal
flood Advisory for the overnight hours.

&&

.SJU WATCHES/WARNINGS/ADVISORIES...
PR...High Rip Current Risk through Sunday afternoon for PRZ001-002-
005-008-010-012-013.

High Surf Advisory until 6 PM AST Sunday for PRZ001-002-005-008-
010-012.

VI...High Rip Current Risk through Sunday afternoon for VIZ001-002.

High Surf Advisory until 6 PM AST Sunday for VIZ001-002.

&&

$$

SHORT TERM...WS
LONG TERM....LIS

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
528 AM AST Fri Dec 9 2022


.SYNOPSIS...

Extremely hazardous marine and coastal conditions will persist
today into the rest of the period, with seas up to 15 feet and
breaking waves up to 20 feet. For today, frequent passing showers
will persist in the morning, diminishing during the day. Expect
relatively fair weather conditions on Saturday, then a cold front
will bring showers Saturday night and Sunday. Somewhat drier
conditions are expected Monday and Tuesday with gentle northeast
winds.

&&

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

Our focus continues to be on the marine situation as the most
critical part of the weather story. Long-period northeasterly swells
will increase in height across the Atlantic and the Caribbean
passages this morning. Seas will begin to decay overnight. Please
refer to the Marine Discussion below for details, including
current statements, advisories and warnings.

Northerly flow of 8 to 16 mph will continue to be generated by the
gradient at low and mid levels between high pressure at the
surface over the northern Gulf of Mexico and a very strong low
pressure almost 1900 miles northeast with a trough than extends
southwest across the western tropical Atlantic. This low will move
another 600 miles north northeast during the next 3 days and
stall on Sunday. A second low may also develop along a cold front
in the western Atlantic and rotate around the southwest of the
first low with the combined northerly flow driving a cold front
into the area. That cold front is still expected to enter our
northern waters early Sunday morning and will likely cross Puerto
Rico and the northern U.S. Virgin Islands during the day. Showers
are expected to continue in the northerly flow during the night
and morning hours along the northern coast of Puerto Rico and the
northern U.S. Virgin Islands with light amounts each day. Very dry
air will remain in place over the area above 8-10 kft and this
will cap the showers and suppress rain amounts. Thus, although
showers will be frequent and mainly during the overnight and
morning hours along the coastal regions, amounts should remain
less than one tenth to one half inch in isolated spots today and
Saturday. Because of the northerly flow, cool air advection will
prevail and help to keep temperatures a degree or two below normal
for this time of year except along the south coastal plains. On
Sunday the front should have clouds and more widespread showers
even though only a slightly deeper moist layer will accompany it.
Rain amounts of one tenth to three quarters of an inch are
possible on Sunday.

The upper level trough moved into the western Tropical Atlantic,
but the ridge just off the coast of eastern Florida will flatten
out and a second trough will take its place west of us and cross
through the area on Saturday night. This will leave us in west
northwest flow of around 45 knots between a 100-plus knot
subtropical jet to our north and a 60 knot jet in the southern
Caribbean south of Hispaniola on Sunday.

.LONG TERM...Monday through Friday.

A surface high pressure over the western Atlantic moving eastward
will maintain the northerly wind flow over the Caribbean. Under
this pattern, drier conditions will persist across the forecast
area. High pressure on Tuesday over the northeast United States
will push a front southward across the western Atlantic. This
will cause the pressure gradient over the local areas to relax
allowing lighter winds across the islands The approach of the
front will cause winds to veer to the east-northeast on Tuesday
into Thursday. Lighter winds can enhance sea breeze variations,
however, the lack of moisture will limit the rainfall activity
during these dates.

According to the latest guidance, a return of the easterly winds
is forecast for late Thursday into Friday as a surface high
pressure moves is crowded into the eastern Atlantic by strong low
pressure and the frontal system now in the north central Atlantic.
Below or near normal temperatures will prevail for the first part
of the period, but a general warming trend is expected through
the end of the period on Friday.

&&

.AVIATION...Mainly VFR conditions will prevail across most local
terminals during the next 24 hours. Passing SHRA will result in
brief mtn obscurations and MVFR conditions thru 09/16Z. N-NE winds
at 5-10 knots will increase to 8-12 knots after 09/14Z with higher
gusts, mainly across northern terminals. Locally higher winds will
also be found near the shower activity. Max winds W 50-60 knots
btwn FL380-460. Winds are northerly blo FL360.

.MARINE...
Hazardous marine conditions will prevail for the rest of the
period due to a northeasterly swell. For today expect seas up to
15 feet across the Atlantic waters and local passages. These
hazardous conditions will persist tonight with seas up to 14
feet. Large breaking waves up to 20 feet will cause dangerous rip
currents, beach erosion, and local coastal flooding conditions
across the islands' northern and eastern sections. Therefore, a
coastal Flood Warning is in effect until 2 AM on Saturday. High
Surf Warnings are in effect as well as are statements for a high
rip current risk. For more information, please refer to the
Coastal Hazard Messages.

&&

.SJU WATCHES/WARNINGS/ADVISORIES...
PR...Coastal Flood Warning until 2 AM AST Saturday for PRZ001-002-005-
008-010-012-013.

High Rip Current Risk through late Monday night for PRZ001-002-
005-008-010-012-013.

High Surf Warning until 2 AM AST Saturday for PRZ001-002-005-008-
010-012-013.

High Surf Advisory from 2 AM Saturday to 6 PM AST Sunday for
PRZ001-002-005-008-010-012.

VI...Coastal Flood Warning until 2 AM AST Saturday for VIZ001-002.

High Rip Current Risk through late Monday night for VIZ001-002.

High Surf Warning until 2 AM AST Saturday for VIZ001-002.

High Surf Advisory from 2 AM Saturday to 6 PM AST Sunday for
VIZ001-002.

AM...Small Craft Advisory until 6 AM AST Tuesday for AMZ710-712-715-
722-741-742.

Small Craft Advisory until 6 PM AST Sunday for AMZ725-732.

&&

$$

SHORT TERM...WS
LONG TERM....LIS

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
448 AM AST Sun Dec 11 2022

.SYNOPSIS...
Issued at 349 AM AST Sun Dec 11 2022

A cold front will move through the area today with slightly cooler,
mostly stable air and a few showers following. Easterly flow will
begin on Wednesday gradually bringing in warmer air and some
better moisture through Saturday. Hazardous marine condtions will
continue. Beaches on the north and northeast sides of the islands
will be most affected by high surf and dangerous rip currents.

&&

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

The remnants of a frontal boundary are making their way over the
islands from the north. This is bringing an increase in moisture
over the region. Shower activity has increased through the night,
and will progress across the region through the morning. Another
band of moisture is forecast to reach northern portions of the
islands around mid to late-morning, further enhancing shower
activity. Still, the mid-levels remain relatively dry, inhibiting
vertical development of the showers, and limiting their strength.
Periods of light to moderate rainfall are expected with these
showers. The steering flow remains generally northerly, and these
passing showers will move from north to south.

As the front remnants and the moisture associated leave the region,
shower activity will decrease once again by this evening or early
tonight. The overall pattern will return to the one of previous
days, with passing showers passing over the islands from north to
south, moreso during the overnight and morning hours. No significant
rainfall is likely. The steering flow does weaken, however, and then
become less consistently northerly by late in the day on Monday. Low-
level winds will become light and variable; by Tuesday, there is a
trend towards these low-level winds becoming more easterly again,
finally. In the mid-levels, however, above around 800 hPa, winds
will be mostly westerly. Some moisture convergence is possible over
the interior of Puerto Rico. Passing showers will likely continue to
affect the islands from time to time, though some westerly motion is
possible (as opposed to the predominantly northerly motion that has
been seen over the last several days). With limited moisture, and
persisting dryness at the mid-levels, however, heavy rain and
significant accumulations are not expected. On the whole, Monday and
Tuesday will bring generally fair weather, though a couple brief
showers are possible from time to time.


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

A strong low over Nova Scotia will make a loop and head east with
a cold front draping down over the western Atlantic and high
pressure behind it. This time, however, the cold front will only
make it as far south as 22 degrees north (250 miles north of San
Juan) around Thursday afternoon. The upper level trough passage
on Tuesday will also mark the end of the cooling trend in the
area. Easterly surface flow thereafter will bring an influx of
more tropical air Wednesday through Saturday during which
conditions will slowly warm and moisten and scattered showers in
the typical diurnal pattern will prevail.

&&

.AVIATION...
(06Z TAFS)
Issued at 349 AM AST Sun Dec 11 2022

VFR conds expected next 24 hours for all aerodromes. SHRA increase
due to frontal remnants; brief MVFR possible then through around
11/22z. Winds light overnight, though variable winds to 10 to 15
knots possible near stronger showers. Winds pick up out of the north
after sunrise, with speeds of around 8 to 12 knots. Max winds W
40-50 kts btwn FL 445-490 and near 40 kts at FL400.

&&

.MARINE...
Issued at 349 AM AST Sun Dec 11 2022

Seas will subside very little during the next 12 hours, then
another, weaker, surge of swell from the north will enter the
area and peak Monday afternoon with seas of up to 10--occasionally
13 feet. Small craft conditions may persist through the next 7
days although seas may briefly subside below 7 feet on Wednesday
evening in the central portion of our outer Atlantic waters. High
surf and high rip current risk are also expected during this
period with lulls along some western and coasts and Vieques.

&&

.SJU WATCHES/WARNINGS/ADVISORIES...
PR...High Rip Current Risk through Thursday evening for PRZ001-002-
005-008-010-012-013.

High Surf Advisory until 8 PM AST Wednesday for PRZ001-002-005-
008-012.

High Surf Advisory until 6 AM AST early this morning for PRZ010.

VI...High Rip Current Risk through Thursday evening for VIZ001-002.

High Surf Advisory until 8 PM AST Wednesday for VIZ002.

High Surf Advisory until 6 AM AST early this morning for VIZ001.

AM...Small Craft Advisory until 2 AM AST Thursday for AMZ710-712-715-
722-741-742.

Small Craft Advisory until 8 AM AST this morning for AMZ725.

Small Craft Advisory until 6 PM AST this evening for AMZ732.

&&

$$

SHORT TERM...CS
LONG TERM....WS/MRR
PUBLIC/AVIATION...CS/MRR

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
421 AM AST Mon Dec 12 2022


.SYNOPSIS...
Marine and coastal conditions continue to be deteriorated, and
will remain as such through much of the workweek. A cold front
moved through the islands, leaving a cooler air mass with some
passing showers over the area. Moisture and temperatures will
increase once again by the end of the workweek.

&&

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

A cold front is now south of the forecast area with cool air
advection in northerly flow in progress. Capping occurs between 9-14
kft, but the moist layer only reaches to 6.5 Kft. Light to moderate
showers are appearing in widely-spaced narrow bands 2 to 4 miles
wide. Cells inside the bands are moving from 350 degrees at 11
knots. Drier air appears in the Total Precipitable Water product
(TPW) behind the latest band. 850 mb GFS relative humidity however
shows a fairly wide band of drier air with 20-30 percent relative
humidity over the forecast area, punctuated by daytime convection
over the interior of Puerto Rico Tuesday through Wednesday as
subsidence occurs between the moist tropical air advancing from the
southeast and another cold front sinking south toward Hispaniola.
The moisture is expected to arrive from the southeast Wednesday
night and Thursday and will be the beginning of warmer weather with
more shower activity.

At upper levels a strong sub-equatorial jet of up to 90 knots is
expected to move over the area this morning with anti-cyclonic flow.
It will sink south as a trough moves through the area Tuesday at 12Z
with a second following on Wednesday at 09Z followed by the passage
of the sub tropical jet to our north near 20 degrees north. Upper
level flow then becomes northwest at about 35 knots.

This will keep conditions relatively stable and precipitable water
values will be several standard deviations below normal from this
morning to Wednesday evening (Thursday 00Z). Temperatures should be
nearly normal as mostly sunny skies bring warm high temperatures,
and drier air allows better radiational cooling at night with lower
than normal minimum temperatures.


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

A mid to upper level ridge will continue to hold over the western
Caribbean through most of the forecast period. This will maintain
all the moisture trapped in the lowest levels of the atmosphere. On
Thursday, a surface trough approaches from the east, but only
bringing a modest increase in showers. This activity should affect
mainly the eastern municipalities of Puerto Rico and the Virgin
Islands. For Friday and the weekend, as a surface high pressure
north of the islands migrates eastward, small pockets of moisture
will move at times across the area. Therefore, a seasonal pattern of
advective showers is expected, with the available moisture fueling
some showers over the west of Puerto Rico. So far, the atmosphere
aloft does not favor any significant event, so rainfall amounts are
expected to remain on the light side. Temperatures should be
seasonal as well, with maximum temperatures around 83 to 85 degrees
for the coastal municipalities, and highs in the upper 70s in the
mountains.



&&

.AVIATION...
VFR conds expected next 24 hours for all aerodromes despite light
SHRA in north flow along the coasts and offshore to our north and
some isold SHRA in the interior btwn 12/17-21Z. Sfc winds bcmg N 8-
12 kts with some hir gust. Maximum winds expected to bcm W 80-90 kts
btwn FL350-450.

&&

.MARINE...
Recent buoy observations at Rincon and San Juan show that seas are
still at small craft advisory criteria. At the outer buoys, a
stronger northerly swell is already evident, with seas up to 11 to
13 feet, and a period of 11 to 13 seconds. Marine conditions will
continue hazardous for most of the workweek.

These seas will maintain coastal conditions hazardous, with high
surf for the north-facing beaches of all the islands but Vieques.
There is also a high risk of rip currents for the north-facing
beaches of all islands.

&&

.SJU WATCHES/WARNINGS/ADVISORIES...
PR...High Rip Current Risk through Friday afternoon for PRZ001-002-
005-008-010-012-013.

High Surf Advisory until 6 PM AST Friday for PRZ001-002-005-008-
012.

High Surf Advisory until 6 PM AST Friday for PRZ010.

VI...High Rip Current Risk through Friday afternoon for VIZ001-002.

High Surf Advisory until 6 PM AST Friday for VIZ001.

AM...Small Craft Advisory until 8 AM AST Friday for AMZ710-712-715-
722-741-742.

&&

$$

SHORT TERM...WS
LONG TERM/PUBLIC....ERG

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
441 AM AST Tue Dec 13 2022

.SYNOPSIS...
Marine and coastal conditions remain a concern for the north and
east facing beaches of all the islands, as a northerly swell
continues to invade the Atlantic waters and passages. These
hazardous conditions will stretch through early in the weekend.
Shower activity will be limited, although with some activity still
possible at times.

&&

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

A weak short wave trough will pass mainly across the northeastern
Caribbean through Wednesday, while a broad upper level ridge builds
across the Caribbean Basin through the short term period. The 500 mb
temperature is forecast to drop to around -11C by 14/06z tonight,
but the precipitable water content today is expected to peak around
1.25 inches by 20z before reaching a PWAT minima of 0.80 inches
through the overnight hours. At lower levels, a col area south of
the region will promote light and variable winds through at least
early Thursday. Then, a low to mid-level ridge across the Tropical
Atlantic will push the remnants of an old frontal boundary across
the region. Therefore, fair weather conditions should continue
through Wednesday, with the exception of locally induced afternoon
showers over portions of the Cordillera and southern PR today, under
light northerly steering winds, and once again on Thursday
afternoon. Seasonable daytime temperatures are expected today and on
Wednesday, with lower than normal minimum temperatures during the
night.


&&

.LONG TERM...Friday through Tuesday...
A seasonal pattern will continue to hold in the long-term portion
of the forecast. A mid level ridge centered over the western
Caribbean will hold, promoting stable conditions aloft. At the
surface, a couple of high pressure system will exit the
southeastern coast of the United States, migrating eastward. This
will maintain the trade winds out of the east, or from the east
northeast, at 10 to 15 mph. In general, any rain activity that
may reach the islands will be dependent of fragmented low level
patches of moisture that are carried by the trade winds. As is
usually the case in these advective patterns, the eastern
municipalities of Puerto Rico, as well as the US Virgin Islands
will be the most affected areas. However, without the support
aloft, these rains are expected to remain on the light side. In
fact, the high resolution models maintain low probability of
precipitation through most of the period.


&&

.AVIATION...Mainly VFR conditions are expected to prevail across
all terminals during the next 24 hours. Sea breeze variations btw 5-
10 kt will prevail in general across all terminals.


&&

.MARINE...
The forecast was adjusted upward based on the latest observations
from the offshore Atlantic buoys. Seas up to 10 feet are expected
to prevail as a long period northeasterly swell invades the local
Atlantic waters and passages. Conditions will remain above small
craft advisory criteria through early in the weekend.

Along the beaches, a coastal flood advisory is now in effect for
northern Puerto Rico, while a high surf advisory is in effect for
the north and east facing beaches of all the islands. There is
also a high rip current risk everywhere, except for the southern
coast of Puerto Rico.

&&

.SJU WATCHES/WARNINGS/ADVISORIES...
PR...Coastal Flood Advisory until 6 PM AST this evening for PRZ001-
002-005-008.

High Rip Current Risk through Friday afternoon for PRZ001-002-
005-008-010-012-013.

High Surf Advisory until 6 PM AST Friday for PRZ001-002-005-008-
010-012-013.

High Rip Current Risk through late tonight for PRZ011.

VI...High Rip Current Risk through Friday afternoon for VIZ001-002.

High Surf Advisory until 6 PM AST Friday for VIZ001-002.

AM...Small Craft Advisory until 2 PM AST Saturday for AMZ710-712-715-
722-741.

Small Craft Advisory until 8 AM AST Wednesday for AMZ725.

Small Craft Advisory until 8 PM AST Friday for AMZ742.

&&

$$

SHORT TERM...DS
LONG TERM....ERG

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
454 AM AST Wed Dec 14 2022


.SYNOPSIS...
Hazardous marine and coastal conditions will continue through the
rest of the workweek and into the weekend as a northerly swell
continues to invade the local waters. Pleasant weather should
continue today, with a slight increase in moisture for tomorrow.
Aside from the marine conditions, no significant weather events
are expected through the next week.

&&

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

A building mid to upper level ridge over the western Caribbean will
extend into the northeastern Caribbean through the short term
period. This will promote stable conditions and drier air intrusion
aloft. At lower-levels, the best moisture content continues over the
Lesser Antilles and across the southeastern Caribbean. Models
continue to suggest that moisture will advect gradually across the
local area late today through Friday, with PWAT peaking near 1.50
inches at San Juan on Friday afternoon. Light and variable winds
dominated by a light sea breeze will continue today, but east to
southeasterly flow btw 850-700mb will return once again by this
afternoon and turn more easterly during the rest of the short term
period. This will bring back slightly warmer temperatures during the
day, but normal to below normal minimum temperatures should continue
in general across all the islands.

Latest hi-res model guidance suggest measurable rainfall amounts
across the USVI and east/southeast PR tonight into Thursday morning,
and over the west/southwestern interior on Thursday afternoon.
Rainfall totals should remain under 1 inch.

&&

.LONG TERM...Saturday through Thursday
The big picture continues to feature a ridge Holding over the
central Caribbean and the southwestern Atlantic. The ridge
promotes a general dry mass above 850 mb, and stable conditions
aloft. At the surface, a couple of high pressure will migrate
north of the islands toward the central Atlantic, maintaining
trade winds coming from the east or northeast at 10 to 15 mph.
During this period, rain activity should be limited to small
pocket of moisture carried by the trade winds. However, the global
models only show isolated to scattered showers affecting eastern
Puerto Rico and the USVI, but with little rainfall accumulation.

&&

.AVIATION...
Mainly VFR conditions are expected to prevail across
all terminals during the next 24 hours. However, light SHRA may move
in and around TJSJ during the early morning hours, and at TJPS
during the afternoon. Sea breeze variations btw 5-10 kt will prevail
in general across all terminals.

&&

.MARINE...
Recent buoy observations sill show seas of 8 feet and a period of
14 seconds. These conditions are expected to continue today, and
another pulse from the swell is expected on Thursday. Marine
conditions should remain hazardous through the weekend.

At the beaches, breaking waves of 11 to 13 feet are expected to
impact the north-facing beaches of all the islands, as well as
northeastern St. Croix. Therefore, dangerous conditions for
beachgoers will continue through the weekend or early next week.

&&

.SJU WATCHES/WARNINGS/ADVISORIES...
PR...High Rip Current Risk through Friday afternoon for PRZ001-002-
005-008-010-012-013.

High Surf Advisory until 6 PM AST Friday for PRZ001-002-005-008-
010-012-013.

VI...High Rip Current Risk through Friday afternoon for VIZ001-002.

High Surf Advisory until 6 PM AST Friday for VIZ001-002.

AM...Small Craft Advisory until 2 PM AST Saturday for AMZ710-712-715-
722-741.

Small Craft Advisory until 8 AM AST this morning for AMZ725.

Small Craft Advisory until 8 PM AST Friday for AMZ742.

&&

$$

SHORT TERM...DS
LONG TERM....ERG

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
516 AM AST Thu Dec 15 2022

.SYNOPSIS...Hazardous seas across the Atlantic waters and
passages, as well as life-threatening rip currents along the north
facing beaches of the islands will persist through next week due
to long period northerly swells. A slight increase in PWAT today
will promote more shower activity than previous days, but the
threat for flooding will remain low. Seasonable weather conditions
are expected to prevail through next week, under the influence of
a building upper level ridge across the Caribbean Basin.


&&

.SHORT TERM...Today through Saturday...
Recent satellite-derived imagery shows a moisture gradient over the
Virgin Islands, with the lower values over Puerto Rico (1.2 inches)
and higher values over the Caribbean waters (1.5 inches). This
moisture field will move across the area, generating a slight
increase in shower activity across the waters, the USVI and eastern
Puerto Rico. However, aloft, high pressure continues to build, with
a dry air mass holding above 850 mb. Therefore, all the moisture is
confined to the lowest levels of the atmosphere. Nevertheless, with
this pocket of moisture crossing the islands today, local effects
will trigger showers a little bit stronger along southwestern Puerto
Rico. This activity could lead to some ponding of water on roadways
and low-lying areas.

Through early in the weekend, a surface high pressure system just
north of the islands will continue to migrate into the central
Atlantic, promoting winds out of the east-northeast at 10 to 15 mph.
Under this wind flow, small patches of moisture will be dragged by
the winds over the area. Precipitable water values will remain
seasonal, around 1.4 inches, so each day passing showers will be
possible over the area, with local effects generating isolated to
scattered showers along the southwestern quadrant of Puerto Rico.
Additionally, since the wind flow is more from the east,
temperatures will not cool down as much, and will remain seasonal,
with temperatures ranging from 70 (lows) to 85 (highs) at coastal
areas, and from 60 to 80 in the mountains.

.LONG TERM...Sunday through Thursday...
An upper level ridge is expected to build over the Caribbean basin
through the long term period. This will continue to promote stable
conditions and drier air aloft, limiting shower development in
general across the islands. A weak surface high pressure northeast
of the region will promote easterly trades through early in the
week and embedded in this flow, shallow patches of moisture will
stream over the area from time to time. By midweek, lighter winds
are expected as the pressure gradient relaxes and a weak front
moves well north of the region. This will be short-lived as the
pressure gradient tightens somewhat in response to a surface low
moving off the US East Coast and a building surface high over the
central Atlantic. Light to moderate winds from the southeast are
expected by then, and moisture levels should increase, but
remaining at normal levels.


&&

.AVIATION...Mainly VFR conditions expected to prevail through the forecast
period. SHRA may move across the eastern half of the CWA, but with
minimal impacts to operations. Additional activity expected for SW
PR after 15/17Z, with mountain obscuration possible. Winds will pick
up after 14Z, out of the NE at 9 to 12 knots, with stronger gusts.


&&

.MARINE...Hazardous and dangerous marine and surf zone conditions
will continue through as secondary pulses from a northerly swell
will continue to arrive over the local Atlantic waters and
passages. Small Craft Advisories, as well as High Surf Advisories
and high risk of rip currents remain in effect. Refer to the
latest Marine Weather message (MWWSJU), Coastal waters Forecast
(CWFSJU) and Coastal Hazard Message (CFWSJU) issued by WFO san
Juan PR for the latest updates and info.


&&

.SJU WATCHES/WARNINGS/ADVISORIES...
PR...High Rip Current Risk through late Sunday night for PRZ001-002-
005-008-010-012-013.

High Surf Advisory until 6 PM AST Friday for PRZ001-002-005-008-
010-012-013.

VI...High Rip Current Risk through late Sunday night for VIZ001-002.

High Surf Advisory until 6 PM AST Friday for VIZ001-002.

AM...Small Craft Advisory until 2 PM AST Saturday for AMZ710-712-715-
722-741.

Small Craft Advisory until 8 PM AST Friday for AMZ742.

&&

$$

SHORT TERM...ERG
LONG TERM....DS
AVIATION...ERG

[underthwx]

Good afternoon Luis, and all....just wanted to wish you and your family a happy holiday season, and all of you out there! Be safe, be well.....peace!

[cycloneye]

Good afternoon Luis, and all....just wanted to wish you and your family a happy holiday season, and all of you out there! Be safe, be well.....peace!

The same to you and your family.

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
431 AM AST Fri Dec 16 2022

.SYNOPSIS...Hazardous seas and life-threatening rip currents will
continue through the weekend due to long period northerly swells.
The threat for flooding will remain low through next week, as the
region remains under the influence of a building upper level
ridge across the Caribbean Basin.


&&

.SHORT TERM...Today through Sunday...
The main feature in the short-term period is a ridge of high
pressure centered over the western Caribbean Sea that continues to
promote dry and stable conditions aloft, with a trade wind cap
inversion around 850 mb. This feature will persist through at least
Sunday, acting as a limiting factor for any strong rains. At the
surface, the winds have shifted from the east and is bringing
patches of enhanced moisture across the islands. This seasonal
advective pattern will persist with periods of passing showers along
eastern Puerto Rico and the United States Virgin Islands. In the
afternoon, some showers may fire up along the southwest, but again,
conditions aloft do not favor significant rainfall accumulations. A
similar pattern is expected today and tomorrow, when precipitable
water values will be around 1.2 to 1.4 inches, which is near
climatological values. However, by Sunday, values drop below 1.0
inch, and therefore, mainly fair weather will prevail with limited
shower activity and clear skies.

.LONG TERM...Monday through Friday...
An upper level ridge is expected to build over the Caribbean basin
during the next several days and hold through the end of the long
term period. Upper level troughs and associated fronts at the
surface will remain mainly north of the region. Therefore, this
weather pattern will continue to promote stable conditions and
drier air aloft, as well as limited vertical development of
showers that could develop in diurnal activity over the islands
each afternoon.

At the surface a high pressure will move slowly from the US East
Coast into the central Atlantic by the end of the long term
period. Then, by Friday a deep layered low over the Eastern
Seaboard and associated front over the western Atlantic will
promote southeasterly winds across the northeastern Caribbean. The
trade wind cap is forecast to relax somewhat, and allow better
pooling of moisture compared to previous day. Therefore, a slight
increase in shower activity is forecast for the end of the week
into the weekend.


&&

.AVIATION...Mainly VFR conditions expected to prevail through the forecast
period. SHRA will move at times near TJSJ and the USVI terminals,
but significant impacts in operations are not expected. SHRA may
also develop after 17Z across SW PR, with mountain obscuration along
the Cordillera Central. Winds will be out of the east at 10 to 12
knots, with stronger gusts.


&&

.MARINE...Hazardous seas, dangerous breaking waves, and life-
threatening rip currents will continue through at least early next
week due to long period northerly swells. Small Craft Advisories,
as well as High Surf Advisories and a High Rip Current Risk
remain in effect for the Atlantic waters and passages, as well
along beaches with northern exposure. Refer to the latest Marine
Weather message (MWWSJU), Coastal Waters Forecast (CWFSJU) and
Coastal Hazard Message (CFWSJU) for detailed information.


&&

.SJU WATCHES/WARNINGS/ADVISORIES...
PR...High Rip Current Risk through late Sunday night for PRZ001-002-
005-008-010-012-013.

High Surf Advisory until 6 AM AST Monday for PRZ001-002-005-008-
010-012-013.

VI...High Rip Current Risk through late Sunday night for VIZ001-002.

High Surf Advisory until 6 AM AST Monday for VIZ001-002.

AM...Small Craft Advisory until 2 PM AST Sunday for AMZ710-712-715-
722-741-742.

&&

$$

SHORT TERM...ERG
LONG TERM....DSR

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
456 AM AST Sat Dec 17 2022

...New SYNOPSIS, AVIATION, MARINE...

.SYNOPSIS...
Hazardous seas across the Atlantic waters and passages, as well
as life-threatening rip currents along the north facing beaches of
the islands will persist through at least early next week due to
several pulses of long period northerly swells. A slight increase
in PWAT today will promote trade wind showers, but the threat for
flooding will remain low. Seasonable weather conditions are
expected to prevail through next week, under the influence of an
upper level ridge across the Caribbean Basin.

&&

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

Coastal conditions continue to be hazardous across the northern
beaches of Puerto Rico and the U.S. Virgin Islands due to the
arrival of a long-period northerly swell. Therefore, expect
dangerous breaking waves and life-threatening rip currents from the
northwest to northeast coast of PR, Culebra, Vieques, St Thomas, St
John, and eastern St Croix. Please avoid visiting these beaches.

A mid-level high pressure over the Caribbean Region will promote
somewhat stable conditions through the short term. However, a surge
of low-level moisture will increase Total Precipitable Water (TPW)
values to around 1.5 inches, near the 50th percentile for December,
bringing trade wind showers across the windward sections of Puerto
Rico and the U.S. Virgin Islands today. Therefore, expect showery
weather early this morning, followed by afternoon convection due to
sea breeze variations. This moisture is trapped mainly at low
levels, below 700 MB, because the high pressure at mid to upper
levels promotes dry sinking air above it and will limit any vertical
development.

Clear and sunny skies are likely on Sunday. The easterly winds will
advect a moist air mass into the region, promoting a sharp increase
in moisture and passing showers by Monday, mainly across the
Caribbean Sea.

&&

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

By Tuesday and Wednesday, a band of moisture south of the islands
will be advected northward increasing precipitable water values to
near normal levels. Ridging aloft, however, will maintain dry and
stable weather conditions at mid- to upper-levels. Therefore, any
showers will not result in significant rainfall accumulations.

For the rest of the workweek, stable weather condtions aloft will
prevail as seasonal low-level moisture embedded in the trades
crosses the islands promoting light showers at times. By next
weekend, models continue to suggest a polar trough and associated
front exiting the U.S. Eastern Seaboard into the northern
Atlantic waters shifting low-level winds out of the southeast
across the northeastern Caribbean. This will allow more moisture
advection into the CWA. Model soundings also show moistening at
mid-levels decreasing the presence of the trade wind cap. This
setup could enhance shower activity across the islands,
especially over windward coastal areas, although rainfall
accumulations will remain on the light side.

&&

.AVIATION...
(06Z TAFS)
Issued at 431 AM AST Sat Dec 17 2022

VFR conditions across the local terminals, but the easterly winds
will bring occasional -SHRA/SHRA over the terminals of JSJ/IST/ISX
today. SHRA will spread into the interior and western PR between
17/15-23z. The land breeze will prevail through 17/13z when E/ENE
winds return at 10-15 kt with land breeze variations.

&&

.MARINE...
Issued at 431 AM AST Sat Dec 17 2022

Although seas have subsided somewhat as observed by the nearshore
buoys, another pulse of a northerly swell will reach the local
waters this afternoon. This will result in hazardous marine
condtions with seas up to 8 feet and occasionally higher through
at least early next week. Hazardous surf zone condtions will also
prevail with breaking waves of 6 to 13 feet. Therefore, Small
Craft Advisories, as well as High Surf Advisories and high risk of
rip currents will remain in effect. Refer to the latest Marine
Weather message (MWWSJU), Coastal waters Forecast (CWFSJU) and
Coastal Hazard Message (CFWSJU) issued by WFO san Juan PR for the
latest updates and info.


&&

.SJU WATCHES/WARNINGS/ADVISORIES...
PR...High Rip Current Risk through late Sunday night for PRZ001-002-
005-008-010-012-013.

High Surf Advisory until 6 AM AST Monday for PRZ001-002-005-008-
010-012-013.

VI...High Rip Current Risk through late Sunday night for VIZ001-002.

High Surf Advisory until 6 AM AST Monday for VIZ001-002.

AM...Small Craft Advisory until 2 PM AST Monday for AMZ710-712-715-
722-741-742.

Small Craft Advisory from 8 PM this evening to 2 PM AST Sunday
for AMZ725.

Small Craft Advisory from 8 PM this evening to 2 PM AST Monday
for AMZ732.

&&

$$

SHORT TERM...CAM
LONG TERM....CVB
AVIATION...CAM

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
437 AM AST Sun Dec 18 2022

...New SYNOPSIS, AVIATION, MARINE...

.SYNOPSIS...
Hazardous marine and coastal conditions will persist at least into
early this week. A dry air mass will support mostly fair weather
conditions today, with some passing showers affecting very
localized areas at times. Patches of low-level moisture will
support showery weather on occasions during the week.

&&

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

Dangerous breaking waves will prevail across the north and east-
facing beaches of Puerto Rico and the U.S. Virgin Islands.
Therefore, expect life-threatening rip currents and isolated beach
erosion from the northwest to the northeast coast of PR, Culebra,
Vieques, St Thomas, St John, and eastern St Croix. Also, Vieques and
southwest PR can expect strong rip currents today.

A mid-level high pressure over the Caribbean Region will promote a
trade wind cap at 850 MB today, confining the moisture below it at
low levels. The mid-level high pressure promotes dry air and
subsidence aloft, as observed in the latest GFS guidance. This
feature will limit the vertical development of any rain activity.
Therefore, expect a mixture of sunshine and clouds throughout the
day. However, the advection of quick passing rains cannot be ruled
out, mainly across the windward portions of PR and the USVI.

Late tonight into Monday, a surface high pressure across the Central
Atlantic Ocean will bring the moisture of the remnants of a modified
old frontal boundary (as a backdoor front), increasing the chance of
rain across the Caribbean Sea. As a result, cold air advection over
warmer waters will promote scattered to numerous showers across the
Caribbean. Local winds may push them inland occasionally across the
Virgin Islands and east Puerto Rico by late tonight or early Monday
morning, but the ridge aloft does not favor significant rainfall
accumulations. GFS guidance put over PR a layer of Precipitable
water between 1.5 and almost 1.90 inches (between the 50th
percentile and above the 75-percentile for December, respectively)
late Morning night into Tuesday. Under this pattern, showery weather
will remain possible each night and early morning due to cold air
advection.



&&

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

The mid- and upper-level ridge will continue to persist into the
weekend. This will inhibit the development of deep, organized
convection and thus the development of widespread, significant
rainfall events. Any shower development throughout the forecast
period will be due to shallow convective activity. Meanwhile, at
lower levels, a broad surface high pressure is expected to build
across the Atlantic basin during the week while a strong polar
trough and associated front gradually exits the U.S. Eastern
Seaboard by the end of the workweek into the weekend. This will
result in an east southeast to southeast wind flow throughout
long-term period.

The proximity of the frontal boundary northwest of the islands and
the surface high pressure across central Atlantic will strengthen
the pressure gradient over the northeastern Caribbean, with winds
forecast to increase by the weekend between 15 and 20 knots, even
slightly higher in some locations. The weather pattern during
this period will be dominated by patches of low-level moisture
dragged by the relatively quick winds promoting overnight and
early morning passing showers across local waters, with some of
this activity moving inland across southeastern and eastern
portions of Puerto Rico and the USVI, followed by locally induced
afternoon activity across western Puerto Rico. The flooding threat
will be low, but ponding of water in roadways and poorly drained
areas can be anticipated.

&&

.AVIATION...
(06Z TAFS)
Issued at 417 AM AST Sun Dec 18 2022

VFR conditions across the local terminals, but the easterly winds
will bring occasional rains over the terminals of JSJ/IST/ISX today.
SHRA will diminish late this morning into the afternoon, but rain
activity will increase from the Caribbean and near ISX after 18/23z.
The land breeze will prevail through 18/13z. Then, expect E winds at
10-15 kt with higher gusts and sea breeze variations.

&&

.MARINE...
Issued at 417 AM AST Sun Dec 18 2022

Hazardous and dangerous marine and surf zone conditions
will continue through at least early this week as a northerly
swell continues to invade the local Atlantic waters and passages.
Small Craft Advisories, as well as High Surf Advisories and high
risk of rip currents remain in effect. Refer to the latest Marine
Weather message (MWWSJU), Coastal waters Forecast (CWFSJU) and
Coastal Hazard Message (CFWSJU) issued by WFO san Juan PR for the
latest updates and info.

&&

.SJU WATCHES/WARNINGS/ADVISORIES...
PR...High Rip Current Risk through Monday afternoon for PRZ001-002-
005-008-010-012-013.

High Surf Advisory until 6 PM AST Monday for PRZ001-002-005-008-
010-012.

High Rip Current Risk through Monday afternoon for PRZ011.

High Surf Advisory until 6 AM AST Monday for PRZ013.

VI...High Rip Current Risk through Monday afternoon for VIZ001-002.

High Surf Advisory until 6 PM AST Monday for VIZ001-002.

AM...Small Craft Advisory until 2 PM AST Monday for AMZ710-712-715-
722-732-741-742.

Small Craft Advisory until 2 PM AST this afternoon for AMZ725.

&&

$$

SHORT TERM...CAM
LONG TERM....CVB

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
507 AM AST Mon Dec 19 2022


.SYNOPSIS...

Hazardous marine and coastal conditions will continue today. A
surface high pressure across the Central Atlantic Ocean will bring
the moisture of the remnants of a modified old frontal boundary
(as a backdoor front), increasing the chance of rain across the
Caribbean Sea. The moisture will slowly drift northward
approaching the islands from the southeast and increasing the
chance for showery weather on Tuesday.

&&

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

Although an upper-level short-wave trough with axis just east of the
local islands is present, the mid-level ridge continues to dominate
the weather pattern aloft. This has caused a trade wind cap at 700
mb to persist with mostly dry and stable weather conditions above
this layer. At low-levels, GOES-16 Precipitable Water imagery shows
values between 0.8 to 1.15 inches across the CWA, which is well
below normal to near normal levels for this time of year. This
weather pattern has promoted mostly fair weather conditions across
the islands with very few passing showers over the local waters
moving inland across coastal areas at times. Expect similar weather
conditions to continue today with a slight increase in showers over
eastern coastal areas of the islands during morning hours as the
area with highest moisture content moves in. Diurnally induced
isolated to scattered showers are forecast to develop over interior
and western portions of Puerto RIco during the afternoon.

For the rest of the short-term period, ridging aloft will persist
inhibiting any potential for deep convective development in the next
few days. However, low- to mid-level moisture content will gradually
increase starting tonight, eroding somewhat the trade wind cap
currently present. This will promote mostly shallow convective
activity for the latter part of the forecast period. Satellite
imagery and Doppler radar show a southwest-to-northeast oriented
band of clouds and showers associated with the remnants of an old
frontal boundary over the Caribbean waters and east of the local
islands. A surface high pressure over the central Atlantic is
forecast to slowly steer the remnants of the frontal boundary
towards the CWA. As steering winds prevail out of the northeast, a
cool advective pattern will promote showery weather by late tonight
into early Tuesday morning. Scattered to numerous showers will
affect the eastern and northern sections of Puerto Rico and U.S.
Virgin Islands during these hours. Later in the afternoon, surface
heating and local effects along with sea breeze convergence will
enhance shower development across western/southwestern Puerto Rico.
Ponding of water in roads and poorly drained areas are anticipated
with this activity. Urban and small stream flooding could be
possible in a few locations.

On Wednesday, winds will shift more out of the east/southeast. Model
guidance suggests a similar weather pattern as the remnants of the
frontal boundary linger. Therefore, expect cloudy skies and shower
development to persist across the islands, with eastern and southern
Puerto Rico to be affected this time during the morning hours and
later developing across interior and western/northwestern Puerto
Rico.

&&

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

The advective pattern will extend into the second part of this
week as the easterlies push patches of moisture with clouds and
showers across the Northeast Caribbean. A short wave trough (at
upper levels) east of the Lesser Antilles will induce trade wind
perturbations, enhancing the showers' frequency across the U.S.
Virgin Islands and Puerto Rico by Friday through the weekend.
However, model guidance shows dry air at mid and upper levels over
the local islands, so organized convection is not anticipated,
just shallow convection. That said, cold air advection across
warmer waters will promote the typical passing showers overnight
and early in the morning across E-PR/USVI, followed by limited
afternoon convection across PR's interior and western sections.

The remnants of a cold front approaching the northeast Caribbean
(remaining off to the north over the Atlantic Ocean) will induce
pre-frontal troughs near PR/USVI promoting showery weather.
Although pesky rains will affect the region, none of the guidance
indicates significant rainfall amounts through the long-term
forecast. However, ponding of water in roadways and poorly
drained areas may be possible.

&&

.AVIATION...
(06Z TAFS)
Issued at 455 AM AST Mon Dec 19 2022

VFR conditions across the local terminals, with VCSH at times for
JSJ/IST/ISX through 19/14z. SHRA is expected across the Caribbean
and near ISX during the afternoon, and later affecting JSJ/IST after
19/23z. The land breeze will prevail through 19/13z. Then, expect
E/NE winds at 10-15 kt with higher gusts and sea breeze
variations.

&&

.MARINE...

Hazardous marine and coastal conditions will continue through
this week as pulses of northerly swells move across the local
Atlantic waters and passages. The wind will be moderate to locally
fresh from the east through much of the week, increasing during
the weekend.

Small Craft Advisories, as well as High Surf Advisories and High
Rip Current Risk Statements remain in effect. Refer to the latest
Marine Weather message (MWWSJU), Coastal waters Forecast (CWFSJU)
and Coastal Hazard Message (CFWSJU) issued by WFO san Juan PR for
the latest updates and info.

Last night the ASCAT showed a broad area of Gale force winds
across the West European Basin of the Northern Atlantic,
foreshadowing a long period swell that will arrive next weekend.
This will further continue the trend of high seas and surf across
the local waters and coastlines. Stay tuned for further updates.

&&

.SJU WATCHES/WARNINGS/ADVISORIES...
PR...High Rip Current Risk through Tuesday afternoon for PRZ001-002-
005-008-010-012-013.

High Surf Advisory until 6 PM AST Tuesday for PRZ001-002-005-008-
012.

High Surf Advisory until 6 PM AST this evening for PRZ010.

VI...High Rip Current Risk through Tuesday afternoon for VIZ001-002.

High Surf Advisory until 6 PM AST this evening for VIZ001-002.

AM...Small Craft Advisory until 2 PM AST Tuesday for AMZ710-741.

Small Craft Advisory until 2 PM AST this afternoon for AMZ712-
715-722-732-742.

&&

$$

CAM, CVB