Caribbean - Central America Weather

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
514 AM AST Tue Sep 10 2019

.SYNOPSIS...
The TUTT will pull away from the region today, while the trend of
somewhat drier air pushing into the area continues. Local effects
and daytime heating have the potential still, though, to initiate
convection and showers, especially in western and interior
portions of Puerto Rico. These showers still have the potential to
cause flooding conditions considering recent precipitation. This
drying trend is anticipated to persist into midweek, with similar
conditions likely during that time period as well.

&&

.SHORT TERM...Today through Thursday...
Moderate shower activity has continued in the offshore
Atlantic through much of the nighttime, associated with the upper
tropospheric trough now moving to the NE. Other minor isolated
showers are occurring south and east of Puerto Rico, and this is
expected to continue into the later morning hours.

Conditions today are generally less favorable for intense shower
activity, given the lack of upper level support. Showers and a few
thunderstorms are still expected, but not like what occurred
yesterday. Drier midlevel tropospheric air will also suppress
convection somewhat. High resolution model guidance suggests the
center of activity for this afternoon will be in western Puerto
Rico, and extending to the NW portion of the island. Given recent
precipitation and subsequent saturated soils and high rivers, some
flooding is possible. Furthermore, low to mid level winds are once
again expected to be fairly slow, leading to slow moving showers and
higher precipitation amounts. Most locations in W. Puerto Rico will
see less than an inch, with isolated areas receiving higher amounts.
Showers will also be possible for eastern Puerto Rico where
streamers set up downstream of Vieques, St. Croix, and El Yunque.

Very similar conditions will persist for the next few days.
Precipitable water values stay near average, which is more than
sufficient to couple with afternoon surface heating and diurnal
effects to produce the usual shower activity. The prevailing flow
will generally be easterly, with a hint of south southeasterly flow.
Thus, showers will continue each afternoon for western Puerto Rico,
with higher rainfall chances in NW PR compared to SW PR.

.LONG TERM...
A weak upper-level low is expected to be positioned to the east
of the islands on Friday, progressing slowly westward through the
weekend. An area of low-level moisture is also anticipated to
begin pushing into the region on Friday; increasing moisture is
likely through the weekend as well. With instability aloft from
the upper-level low and this sufficient source of moisture,
showers and convective activity are likely, spurred on by local
effects and daytime heating, especially during the afternoon and
evening.

On Sunday, the GFS shows a tropical cyclone developing as it makes
its way past the Leeward Islands into the Caribbean, and then
moving west/northwestward, with a track taking it south of the
islands of Puerto Rico and the U.S. Virgin Islands. In contrast,
the ECMWF shows development associated with this tropical wave
occurring much more slowly, with a potential tropical cyclone not
appearing until late Tuesday or Wednesday, with the system
northwest of Puerto Rico. This model solution also suggests a
significantly weaker system. It is also worth noting that the most
recent GFS run shows a later-developing and weaker system than
prior runs. Considering this still substantial lead time, as well
as the lack of model agreement, there is low confidence in any
forecast for this potential future tropical cyclone, and as such
its possible existence is not reflected in the forecast. Either
way, a tropical wave is likely to pass by or over the region early
next week, providing increased moisture.

&&

.AVIATION...
Mostly VFR conditions expected through 07/14z, though there are
isolated showers offshore. SHRA/TSRA expected across PR between
07/16z and 07/22z, mainly in the the vicinity of TJMZ and TJBQ,
with TEMPO MVFR conditions possible. VCSH is also possible for
TJSJ. Winds light and variable through 07/12z, increasing to 10 to
15 kts from the E with sea breeze variations after 07/14z.

&&

.MARINE...
Marine conditions will remain relatively tranquil, with wave
heights up to 3-5 feet possible through the rest of the week. A
small swell out of the north/northeast will persist today,
bringing longer period waves to the area. There is a low to
moderate rip current risk today for most beaches along the
northern coasts of all islands; however, north central beaches of
Puerto Rico have a moderate to high risk of rip currents.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 91 79 91 79 / 40 30 30 30
STT 90 80 90 80 / 30 30 30 30

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
501 AM AST Wed Sep 11 2019

.SYNOPSIS...
There remains some lingering moisture over the area today. As the
upper-level low continues to pull away to the northeast, and a
mid-level ridge builds in from the east, increasing stability is
anticipated. This stability is not expected to be strong enough to
serve as suppression for convective activity. Local effects and
diurnal heating will be the dominant forcings as we move into the
end of the week. Showers and isolated thunderstorms will have the
potential to cause urban and small stream flooding, especially in
western portions of Puerto Rico. This weekend, the arrival of a
tropical wave will herald increasing shower and thunderstorm
activity.

&&

.SHORT TERM...Today through Friday...
A mid level ridge building from the east will be the dominant
weather feature through the short term period. This will promote
drier air aloft and more stable conditions than previous days as we
had with an upper level trough, which is currently located just
northeast of the Leeward Islands. At lower levels, weak steering
winds will continue between 8-12 knots from the east-southeast and a
shallow layer of moisture will prevail from the surface to around
750mb. Although, the mid level ridge will remain in place over the
area, it won`t be strong enough to suppress convective activity and
the potential for urban and small stream flooding should continue
for the next couple of days with the heaviest showers over western
Puerto Rico.

In general, diurnally induced afternoon showers and thunderstorms
are expected each day, mainly over the northwest quadrant of Puerto
Rico and over portions of the interior and the San Juan metro area
due to the combination of the available low level moisture, day time
heating and the sea breeze convergence. Across the U.S. Virgin
Islands, light trade wind showers and streamers developing off the
islands could result in mostly minor rainfall amounts through at
least Friday. Max temps will range from the high 80s to low 90s and
the heat index should range from the high 90s to low 100s each
afternoon along the lower elevations of the islands.

.LONG TERM...Saturday through Wednesday...
An upper level trough is expected to be located southeast of the
region on Saturday, to slowly progress south of the islands
through the weekend. Moisture associated with a weak tropical wave
is also expected to arrive during the latter part of the day on
Saturday. This, combined with local effects and diurnal heating,
will help to induce showers and isolated thunderstorms, especially
in the afternoon into the evening.

Model guidance continues to suggest the potential for development
with the next tropical wave, passing by to the south of the region
early in the week. That being said, there is still very little
agreement from the models, and a lack of consistency between runs;
as such there is correspondingly low confidence in the possibility
for this potential tropical cyclone development, especially given
the lead time. Because of this, this possible solution is not
reflected in the forecasts. Whether this system develops or not,
before or after passing by the islands, a tropical wave is likely
to bring increased moisture to the area lasting into Wednesday.

&&

.AVIATION...
Mainly VFR conditions are expected to prevail across all
terminals during the next 24 hours. However, passing trade wind
showers may result in RA/VCSH across the Leeward/USVI/Eastern PR
terminals through the morning hours. Afternoon SHRA/TSRA should
cause tempo MVFR conditions at TJMZ/TJBQ. E-ESE winds expected
between 8-12 kt with sea breeze variations after 14z at
TJSJ/TJBQ/TJMZ.

&&

.MARINE...
Typical marine conditions are expected to persist today and into
this weekend, with seas up to 3-5 feet, despite a small and
diminishing northerly swell. Light to moderate winds will
continue to be generally out of the east today and into tomorrow,
becoming more east- southeasterly as we move towards the weekend.
There is a low to moderate risk of rip current on north-facing
beaches across Puerto Rico and the U.S. Virgin Islands today.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 89 79 91 80 / 30 30 30 30
STT 90 80 89 80 / 40 40 20 30

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
445 AM AST Fri Sep 13 2019

.SYNOPSIS...

More showers and thunderstorms are expected across the region for
the next few days. Potential impacts associated with these
thunderstorms include heavy rain, frequent lightning, gusty
winds, and urban and small stream flooding. Into next week, the
forecast becomes more difficult as a few tropical waves head
towards the Caribbean from the east. Saharan dust early next week will
result in hazy skies.


&&

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

A mid level ridge will continue over the area through at least
Saturday as it moves west. However, the ridge is not strong enough
to suppress convective activity. Therefore, diurnally induced
showers and isolated thunderstorms are expected once again this
afternoon, due to the combination of the available low level
moisture, day time heating and sea breeze convergence. Heavy showers
and saturated soils due to previous days rainfall could lead to
quick urban and small stream flooding, especially over the interior
and western sections Puerto Rico and as well over the San Juan metro
area. Light steering east to southeast winds will continue
today...winds turn more from the east on Saturday and from the east
to northeast by Sunday. An upper level low will approach the area
from the northeast and due to the proximity of the low, showers
could be heavy at times. A similar weather pattern is expected on
Saturday in general for Puerto Rico. Normal to above normal
temperatures are expected to continue today.

Across the U.S. Virgin Islands, a fair weather pattern should
continue with mostly sunny to partly cloudy skies during the early
morning hours and streamers developing over and to the west-
northwest of the islands between the late morning through early
afternoon hours. This may result in minor rainfall accumulations
over land areas. A tropical wave is still forecast to move across
the eastern Caribbean on Sunday morning and scattered to locally
numerous showers and isolated thunderstorms could increase in
frequency and intensity across the islands and surrounding waters.


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

Long-term forecast model projections for the next workweek vary
substantially. The usual shower activity can be expected,
specifically for western Puerto Rico, as well as isolated showers
elsewhere. However, the degree of intensity at this point is
difficult to decipher given the high uncertainty of the
situation. The uncertainty will primarily come from areas of
disorganized thunderstorms between our region and Africa that have
the potential to develop into organized tropical systems. It is
unknown if any of these potential systems make it into our region,
but the very existence of these systems complicates the long-term
forecast.

The key takeaways for the long-term forecast are the following: 1)
Saharan dust is expected to arrive Monday and last into the middle
of the workweek. 2) Despite the Saharan influence, a tropical wave
is also expected Monday. One forecast model has it moving south of
the region, and another has quite a bit of moisture arriving. Expect
scattered showers, but the intensity is uncertain. 3) The middle of
the workweek looks fairly typical for this time of the year, with
the usual diurnally induced shower activity and warm temperatures.
4) By the end of the workweek, models suggest another batch of
moisture moving in, and it does has the potential to develop into an
organized tropical system. Honestly, whether is does or does not
develop, or even move into our region at all, is completely unknown.
5) Atmospheric conditions look quite favorable (due to a Kelvin Wave
and MJO event) for an active tropical Atlantic for the latter
half of the month. At this point our region has nothing to worry
about, but as usual we should all be prepared and attentive to the
latest forecast...which hopefully will have a little less
uncertainty in the coming days.


&&

.AVIATION...

Mainly VFR conditions are expected to prevail across all
terminals during the next 24 hours. However, SHRA/TSRA btw 16z-22z
may cause tempo MVFR to brief IFR conditions at TJMZ/TJBQ. ESE winds
expected at 5-10 kt with sea breeze variations after 14z.


&&

.MARINE...

Calm marine and weather conditions are expected to continue
into the weekend, with seas at or below 5 feet. Winds will be out of
the east between 5-15 knots. Into next week, higher seas of up to 7
feet are possible as a tropical wave moves into the region. A low
risk for rip currents exists for the rest of today, after which a
moderate risk is expected for the northern beaches of Puerto Rico
over the weekend.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 91 81 91 79 / 40 50 50 60
STT 90 81 91 81 / 30 50 50 60

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
455 AM AST Sat Sep 14 2019

.SYNOPSIS...

A seasonal weather pattern with locally induced showers and
isolated thunderstorms are possible through early next week. A
tropical wave is forecast to move into the area late Monday into
Tuesday this wave will increase showers and thunderstorms across
the region.

&&

SHORT TERM...Today through Monday...

A seasonable weather pattern will continue with trade wind showers
across the windward sections of Puerto Rico and the U.S. Virgin
Islands, followed by afternoon convection along and west of the
Cordillera Central in Puerto Rico. Showers and isolated
thunderstorms are also expected to develop across the west-end of
the U.S. Virgin Islands and downwind from El Yunque into the San
Juan metro area during the afternoon hours. Periods of heavy showers
over saturated soils could lead to quick urban and small stream
flooding, especially over the interior and western sections Puerto
Rico, but also over the San Juan metro area.

Although today`s afternoon convection is expected to diminish across
west Puerto Rico around sunset, a weak tropical wave is still on
track to affect our archipelago late tonight into Sunday. This
tropical disturbance will bring an increase in the available
moisture with precipitable water values ranging between 2.0 and
2.25. As a result, low-level convergence will enhance shower
activity across the Virgin Isles and the eastern half portion of
Puerto Rico overnight and early Sunday morning. Then, daytime
heating, local effects and sea breeze convergence will promote
numerous showers and scattered thunderstorms across the interior and
western sections of Puerto Rico.

Model guidances are indicating the arrival of a slot of drier air
with Saharan air particles on Monday. Therefore, fair weather
conditions with limited shower activity, warm temperatures and hazy
skies are expected to prevail. However, another tropical wave will
bring a sharp increase in the available moisture late Monday night
into Tuesday.

&&

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

There is a lot of uncertainty during the later part of next week.
What is certain si a tropical wave that is currently 400 miles
east of the Lesser Antilles will transverse the area late Monday
night into Tuesday morning. The tropical wave moisture will cause
precipitable water values to skyrocket, guidance shows a value of
2.33 inches. If this value verifies it will rank near the 99th
percentile for the month of September. Also, an east to southeast
wind flow coupled with surface heating and orographic effects will
lead to the development of numerous showers and thunderstorms
Tuesday afternoon.

Wednesday and Thursday, the deep tropical moisture propagates
east of Puerto Rico, however, the bulk of the moisture is expected
to remain across the southern Caribbean waters. Although,
tropical moisture will remain south of most of the local islands,
an east to southeast wind flow, diurnal heating and local effects
will cause showers and isolated thunderstorms during the
afternoon. Numerous showers are not expected to develop due to the
Saharan air mass which will advance into the area on Wednesday.

Late Thursday through the end of the week is where the forecast
becomes more uncertain, as a result of several tropical waves
currently east of the Lesser Antilles. The global models have
develop the tropical wave over the last several days, then on
subsequent runs they show no development. Today the GFS and EURO
develops one of the tropical waves 2000 miles east of the Lesser
Antilles late Monday or early Tuesday morning. The GFS and EURO
develops the tropical wave, and takes it on a northwest heading
across the Atlantic. At this time a northwest movement will keep
the tropical cyclone away from the local area and across the
central Atlantic. However, I want to emphasize that the
development of the disturbances is not set in stone, and many
things can change over the next several days. Therefore, continue
to monitor the Tropical Weather Outlook from NHC for details about
the disturbances east of the Lesser Antilles.

&&

.AVIATION...

VFR conds expected across the USVI/PR terminals through
at least 14/16Z. Thereafter, SHRA/TSRA expected to form downwind
from the USVI and El Yunque near JSJ/IST/ISX as well as across the
Mountain Range of PR near/over TJBQ and TJMZ. NCM/KPK can expect
passing SHRA at times with some iso-TSRA across the local waters and
some of them could move inland thru at least 14/20z. Calm to light
and VRB winds until 14/13z. After 14/13z easterly winds will return
between 10 and 15KT with sea breeze variations

&&

.MARINE...
Seas are forecast to be below 5 feet with winds of 10 to 15 kts
today. A tropical wave will cause an increase in showers and
isolated thunderstorms, as well as a slight increase in seas. A
moderate risk of rip currents is expected for the northern
beaches of Puerto Rico and Cramer Park in Saint Croix, with a low
risk expected elsewhere through Saturday.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 92 79 90 81 / 20 60 60 40
STT 91 81 89 80 / 50 60 60 40

[msbee]

Good afternoon
We are at the height of hurricane season right now and there are a few waves to the East that I am watching.
I subscribe to Crown Weather and this is an excerpt from Rob LIghtbown on the waves out there.

"Tropical Waves Between The Lesser Antilles & The Coast Of Africa: The area between the Lesser Antilles and the coast of Africa is just a huge mess of westward tropical disturbances that all seem to be competing with each other.
The first tropical wave is located about 900 miles or so to the east of the Lesser Antilles very near 45 West Longitude. This tropical wave is moving at a quick forward speed and because of this, development is not expected anytime soon, if ever. This first tropical wave is likely to bring some gusty showers and thunderstorms to the Lesser Antilles on Monday.

A tropical disturbance that is located over the eastern Atlantic in the vicinity of 35 West Longitude is being watched closely for potential development in the coming days. This disturbance is likely to push westward and probably will become a tropical depression and then a tropical storm next week.

At this point, it looks possible that this tropical disturbance will be guided to the north of the Lesser Antilles by the “wake” left behind by Humberto. All of the model guidance forecast that this seems to be the most probable scenario. With that said, I am still gong to keep an eye on this tropical disturbance in case we see a further west track than what is being suggested right now."

[cycloneye]

Area Forecast Discussion...
National Weather Service San Juan PR 459
AM AST Sun Sep 15 2019

.SYNOPSIS...

A tropical wave and its associated moisture has moved into the
Caribbean waters this morning. This wave is expected to continue
to move west and cause showers and thunderstorms across Puerto
Rico and adjacent islands today.

&&

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

Satellite and radar imagery depicted a tropical wave generating
numerous showers and thunderstorms across the Caribbean Sea and
Atlantic Ocean. Good moisture associated with this wave will pool
over the islands today. That said, expect showers and thunderstorms
mainly across the Caribbean and Atlantic waters as well as across
U.S. Virgin Islands and the north and eastern sections of Puerto
Rico through the morning hours. This activity will then spread into
the interior and western portions of Puerto Rico. As a result,
periods of heavy showers will lead to quick urban and small stream
flooding, especially over the interior and western sections Puerto
Rico, but also over the San Juan metro area. The combination of
daytime maximum temperatures and plenty of moisture will result in
heat indices in the mid 100s, especially along the coastal areas.

Although a seasonable weather pattern will continue across the
islands on Monday, a slot of dry air with Saharan air particles may
produce hazy skies. Another tropical wave is still expected to
produce a sharp increase in the available moisture Monday night into
Tuesday morning. Then, a larger area of dry air with a higher
concentration of Saharan dust will filter from the east Tuesday
afternoon into the long term period.

&&

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

A dry Saharan air mass will hold across the region through
Wednesday, and cause precipitable waters to rapidly decline. In
addition, the dry Saharan air will limit the development of
widespread showers and thunderstorms, however, showers and
isolated thunderstorms will develop as a result of local and
diurnal effects. Mid-day Thursday a weak tropical wave will push
into the region from the east and increase low-level moisture, and
showers and thunderstorms. This wave is expected to quickly race
off to the west leaving behind some residual moisture on Friday.

Saturday, another tropical wave is forecast to transverse the
region, and increase showers and thunderstorms just like the
previous tropical wave. The tropical wave will exit to the west
late Sunday, but the wave will continue to pull moisture from deep
tropics across Puerto Rico and adjacent islands. The deep
tropical moisture coupled with significant heating and local
effects will induce showers and thunderstorms through the
beginning of the workweek.

&&

.AVIATION...

Brief MVFR psbl at TKPK as a trop wave moves across
the local flying area. This tropical wave will bring SHRA/TSRA
across the surrounding waters of PR/USVI. The terminals of USVI/E-PR
will be affected after 15/12z and W-PR after 15/15z. MVFR conds and
brief IFR conds may be possible btwn 15/16-22z, especially at
JMZ/JBQ/JSJ. Winds will continue calm to light and VRB until 15/13z.
Easterly winds at 10-15 knots with sea breeze variations and higher
gusts will return after 15/13z.

&&

.MARINE...

A tropical wave will cause seas to reach up to 6 feet across the
Anegada Passage. Elsewhere, seas up to 5 feet winds will range
from 10 to 15 knots with higher gusts. Showers and thunderstorms
are expected across the local and regional waters this morning
and afternoon. Therefore, small craft operators are urged to
exercise caution. A moderate risk of rip currents for the
northern, Southwestern, and southeastern beaches of Puerto Rico.
There is a moderate risk of rip currents for the southern beaches
of Vieques, northern beaches of U.S. Virgin Islands, and northern
beaches of Culebra.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 92 80 90 79 / 50 50 50 50
STT 90 80 90 81 / 50 30 30 30

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
504 AM AST Mon Sep 16 2019

.SYNOPSIS...
A wet weather pattern is expected across the islands through at
least mid-week. Therefore, expect passing showers across the
windward sections overnight and in the morning, followed by
afternoon convection across the mountain and western portions.
Another tropical wave is still on track to arrive this afternoon
into Tuesday, increasing shower and thunderstorm activity. A
Saharan air mass will arrive late Tuesday night into mid-week.

&&

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

A wet trend will continue through Tuesday as a result of increased
moisture from a tropical wave. Showers embedded in the easterly
trades continued to move west across the local and outer waters this
morning with light rainfall amounts. Later this morning a narrow
band of direr air will filter across the U.S. Virgin Islands,
Culebra, Vieques and limit shower activity. This drier air will
spread across Puerto Rico through the remainder of the morning
hours. A tropical wave and its associated moisture are expected
to enter the forecast area this afternoon and continue to advance
across Puerto Rico through the evening. The available moisture
combined with diurnal heating and local effects will induce
showers and thunderstorms this afternoon across Puerto Rico and
adjacent islands. The heaviest activity will develop over portions
of western and southwestern Puerto Rico. The moderate to heavy
rainfall could cause urban and small stream flooding, as well as
ponding of water on roadways. This activity will be enhanced due
to surface base cape of 3000 J/Kg, low-level moisture, and east
to southeast winds.

Tuesday, the deep tropical moisture is forecast to remain entrenched
across the area. Therefore, expected showers across eastern Puerto
Rico and adjacent islands during the morning, followed by showers
and thunderstorms across portions of interior and western Puerto
Rico. Also, due to moderate to heavy rainfall and saturated soils
from previous days, urban and small stream flooding is likely.

Wednesday, a drying trend will commence due to the tropical wave and
its associated moisture moving away from the area. As the tropical
wave moves away, a dry Saharan air mass will infiltrate the region
from the east. The drier air mass will limit the development of deep
convection and cause precipitable water values to plummet between
1.3 and 1.5 inches. Nevertheless, showers and isolated
thunderstorms are possible as a result of significant heating
coupled with local effects.

During the afternoon hours before the initiation of convection I
would not be surprised if daytime temperatures increased rapidly
as a result of east to southeast wind flow and compressional
warming. If the above happens, heat indices will increase to
moderate to high across the region.

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

The confidence is low-medium through the long-term forecast
because the weather conditions will depend on Humberto`s final
track and the evolution of Invest 97L. However, model guidance
are suggesting dry air moving from the northeast and tropical
moisture approaching from the southeast into the region by
Thursday afternoon. Residual moisture associated with this
tropical perturbation will persist through at least Friday.

The tropical disturbance, Invest 97L, is forecast to approach the
Lesser Antilles by Saturday, increasing the available moisture
across the region. Based on the latest model guidance, this
tropical disturbance will move off to the north of the islands
pulling abundant tropical moisture over Puerto Rico and the U.S.
Virgin Islands throughout the weekend. If model are correct,
deep tropical moisture combined with local effects and diurnal
heating will aid in the development of showers and thunderstorms
through at least Sunday. A seasonal weather pattern is forecast
to return by the beginning of next work-week.

&&

.AVIATION...
VFR conds are being observed across all terminal sites. VCSH/SHRA
will continue moving near the USVI and PR eastern terminals
through 16/15Z. This activity will spread across PR western
terminals by 16/15Z. Winds will continue from the E to SE between
15 and 20 knots with higher gusts and sea breeze variations
through 16/22z.

&&

.MARINE...
A couple of tropical waves will bring showers and thunderstorms
across the regional waters through at least Tuesday. Mariners can
expect seas up to 5 feet through the morning hours, then are
expected to slowly increase this afternoon into the rest of the
week. Therefore, small Craft operators are urge to exercise
caution due to increasing seas around 6 feet by this afternoon.

A northeasterly swell is expected to arrive across the Atlantic
Waters and Anegada Passage by Tuesday. This swell will increase
seas between 6 and 8 feet across the Atlantic Offshore waters and
between 5 and 7 feet across the Atlantic coastal waters and
Caribbean Passages. Therefore, a Small Craft Advisory is in effect
from Tuesday through at least midweek. Hazardous seas are forecast
to persist and will be likely that we extend the Small Craft
Advisory through much of the forecast period.

For the beach goers, there is a high risk of rip currents from the
North Central to Northeast beaches of Puerto Rico and Culebra.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 90 79 91 79 / 50 50 30 10
STT 89 81 90 81 / 60 60 20 20

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
447 AM AST Tue Sep 17 2019

.SYNOPSIS...
A tropical wave and its associated moisture will exit the area
through the morning giving way to a dry Saharan air mass.
Although some passing showers should not be ruled out across the
windward sections, hazy skies are expected to prevail. Locally
induced showers and thunderstorms will then form over the
northwest quadrant of Puerto Rico. Saharan dust particles will
persist through at least late Wednesday night.

&&

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

A tropical wave and its associated moisture will exit the area this
afternoon giving way to a dry Saharan air mass. The Saharan air will
limit shower activity today through Wednesday, resulting in hazy
skies. Precipitable water values are expected to plummet from 2.0
to 1.5 inches this afternoon due to the drier air. In addition,
the drier air mass and east to southeast wind flow will cause
afternoon temperatures to soar throughout the region. The high
daytime temperatures combined with high relative humidity values
will result in three digit heat indices today through Wednesday.

Each day during the short-term period showers are possible during
the afternoon as a result of local and diurnal effects. However,
the dry Saharan air mass will cause showers that develop to be
short-lived due to the lack of upper-level support.

Thursday, tropical moisture from the Caribbean waters will lift
across Puerto Rico and adjacent islands. The increased moisture
will aid in the development of showers and isolated thunderstorms
during the afternoon. Precipitable water values are forecast to
climb over 2.0 inches, the added moisture plus increased
instability will cause showers and isolated thunderstorms to
linger. This could lead to urban and small stream flooding, and
ponding of water on roadways.

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

A seasonal weather pattern it`s possible for Friday, with trade
wind showers over the windward sections during the morning,
followed by afternoon convection across mountains and western
portions.

The National Hurricane Center is giving 90 percent chance of
formation to Invest 97L, which both, GFS and ECMWF, put it as a
tropical cyclone moving off to the northeast of the islands
Saturday. If Invest 97L follows GFS and ECMWF suggested track, it
will pull plenty of tropical moisture across our County Warning
Area (CWA). Confidence is medium, as most of the model guidances
put it away from our CWA, off to the north and moving
northwestward. That said, this tropical disturbance will pool deep
tropical moisture which combined with local effects and diurnal
heating will aid in the development of showers and thunderstorms
through at least Sunday.

A dry trend with suspended Saharan dust particles on Monday and
early Tuesday. Another tropical wave is forecast to reach the
islands Tuesday afternoon into Wednesday.

&&

.AVIATION...
VFR conds are currently prevailing across all terminal sites.
ISO/SCT SHRA are possible at the eastern terminals of PR/USVI
through 17/12Z. Brief MVFR conds are possible due to development
of VCTS/TSRA near terminals TJBQ/TJMZ by 17/18Z. This activity
will cease by 18/02Z then VFR conds expected to prevail. Sfc
winds calm to light and vrb, returning out of the E-ESE at 15 to
20 kts after 17/13z.

&&

.MARINE...
A series of swells are expected to affect the local area through
the forecast period. A northeasterly swell will continue to create
hazardous marine conditions with seas up to 10 feet across the
Atlantic and Caribbean Passages through Wednesday. Then, a
northwesterly swell generated by Hurricane Humberto will spread
across the local waters Thursday, and through early next week.
Small Craft and High Surf Advisories, as well as a High Rip
Current Risk are in effect due to these events. Please, refer to
the Coastal Hazards Message (CFWSJU) and Marine Weather Message
(MWWSJU) issued by the National Weather Service, San Juan office
for more information regarding these hazards.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 92 79 93 79 / 40 20 30 30
STT 90 81 89 80 / 40 20 40 40

&&

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
433 AM AST Wed Sep 18 2019

.SYNOPSIS...
A dry air mass with Saharan dust will continue over the islands
today. Although hazy skies with warm temperatures will prevail
today, diurnally induced afternoon convection are expected to
develop over western Puerto Rico. Tropical moisture is forecast to
lift northward over the islands late Wednesday night through the
end of the work-week. National Hurricane Center`s intensity/track
forecast has Tropical Depression Ten moving westward and about
130 miles from St Thomas/St John and about 145 miles from Culebra
as a Hurricane early Saturday morning.

&&

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

A plume of tropical moisture, associated to a departing tropical
wave, is expected to affect the forecast area as it lifts northward
by Humberto`s movement today and Thursday. This activity is
forecast to favor the Caribbean waters and Mona Passage, but
showers and thunderstorms are expected to move inland across
portions of southern and western Puerto Rico. In the meantime,
overnight and early morning trade wind showers are expected to
move over eastern Puerto Rico and the U.S. Virgin Islands from
time-to-time. Although diurnal heating and local effects may
somewhat enhance shower and thunderstorm development, daytime
cloud coverage may limit the intensity and extent, if any, of this
activity. In contrast, mostly clear to partly cloudy skies with
suspended Saharan dust is expected over the eastern half of Puerto
Rico and the U.S. Virgin Islands. This will support the
development of streamer-like showers moving over the San Juan
metropolitan area, as well as over eastern Puerto Rico in the
afternoon. Under the expected south-southeasterly flow, daytime
high temperatures are forecast to peak in the upper 80s to mid 90s
with heat index possibly into the mid 100s along coastal areas. A
similar weather pattern is expected on Thursday with showers and
thunderstorms favoring the local waters and southwestern quadrant
of the island. Nevertheless, locally induced showers and
thunderstorms are possible in the afternoon.

For Friday...A patch of relatively drier air is expected to reach
the region ahead of Tropical Depression Ten. Although this could
limit shower and thunderstorm development, there is still a
potential for locally induced convection. As the day progresses and
Tropical Depression Ten continues to approach the forecast area,
showers and thunderstorms could affect portions of the U.S. Virgin
Islands and eastern Puerto Rico. Nevertheless, there is still
uncertainties about the intensity and track of this system and its
impacts across the local area.

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

The latest National Hurricane Center`s (NHC) intensity/track
forecast has Tropical Depression Ten (TD-10) moving westward and
about 130 miles from the northern U.S. Virgin Islands and about
150 miles from Culebra/northeast-PR as a Hurricane late Friday
night and early Saturday morning. If the intensity forecast is
correct, TD-10 will be named Jerry with a Cat-1 intensity.
Therefore, everyone with interest in the islands should monitor
the tropical cyclone forecast. Based on the latest NHC forecast
and regardless of its final track, hazardous marine conditions and
a wet pattern will be likely throughout the weekend.

A drying trend is likely to follow TD-10 late Sunday night into
Monday. That said, little to no rain activity with hazy skies and
warm temperatures could be possible briefly early next week.
Then, model guidances are suggesting another tropical wave moving
across the region and increasing precipitable water values
between 2.0 and 2.5 inches Tuesday and Wednesday.

&&

.AVIATION...
Mainly VFR conds across all terminals through the next 24 hours.
However, VCSH are expected at TJPS and TJMZ through the forecast
period. VCTS posible with BKN030-040 at TJBQ and TJMZ between
18/16-23Z. This could result in brief MVFR conditions. Light and
variable surface winds will hold through 18/14Z, turning from the
ESE between 10-15 knots with sea breeze variations thereafter.

&&

.MARINE...
A northerly swell will continue across the Atlantic waters and
passages through Wednesday. This will be followed by a larger
swell from the north-northwest from Hurricane Humberto beginning
Wednesday night and possibly continuing beyond Friday. In addition,
Tropical Depression Ten is forecast to strengthen into a
hurricane and pass north-northeast of the region late Friday night
and Saturday. This will maintain hazardous marine conditions
through the end of the week. Small Craft Advisory and a High Rip
Current Risk are in effect due to these events. In addition, a
High Surf Advisory will continue in effect until 6 AM AST early
this morning. Please, refer to the Coastal Hazards Message
(CFWSJU) and Marine Weather Message (MWWSJU) issued by the
National Weather Service, San Juan office for more information
regarding these hazards. Additional products will be necessary if
the forecast holds.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 93 80 90 79 / 30 30 30 30
STT 90 82 89 79 / 40 40 20 20

[cycloneye]

The government of St. Maarten has issued a Tropical Storm Watch for
St. Maarten.

Meteo-France has issued a Tropical Storm Watch for St. Martin and
St. Barthelemy.



The government of the Netherlands has issued a Tropical Storm Watch
for Saba and St. Eustatius.

[cycloneye]

The government of Antigua and Barbuda has issued a Tropical Storm
Watch for Barbuda and Anguilla.


SUMMARY OF WATCHES AND WARNINGS IN EFFECT:

A Tropical Storm Watch is in effect for...
* Barbuda
* Anguilla
* St. Maarten
* St. Martin
* St. Barthelemy
* Saba and St. Eustatius

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
545 AM AST Thu Sep 19 2019

.SYNOPSIS...Hazardous marine conditions are expected to hold
through the weekend due to a series of northerly swells spreading
across the local waters. As a result, a High Rip Current Risk, as
well as Small Craft, High Surf and Coastal Flooding Advisories are
in effect. A wet weather pattern is expected through most of the
forecast period. This will be the result of lingering showers and
thunderstorms from a meandering tropical wave today, then due to
the passage of Tropical Storm Jerry north of the region Friday
through Sunday, and with the arrival of the next tropical wave or
potential tropical cyclone late Monday night through at least
Thursday.


&&

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

A line of showers and isolated thunderstorms affected the local
waters and Puerto Rico during the overnight hours. This line of
showers has since weakened but spread wider and now is affecting a
larger portion of Puerto Rico with light to moderate showers. The
latest satellite imagery and guidance would suggest tat the shower
activity will persist through at least 10 AM or so, but the
cloudiness could prevail through the rest of the day. That said, the
northwestern sections of PR has the higher chance of showers and
thunderstorms this afternoon.

Tropical storm Jerry is currently at 16.0N and 53.2W with winds near
70 MPH. The latest track forecast still has Jerry at over 100 miles
to the north northeast of the local islands. However, moisture and
rain bands associated with the storm could affect the local islands,
bringing showers and thunderstorms to the area on Friday and
Saturday into early Sunday.

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

As Tropical Storm Jerry or soon to be Hurricane Jerry moves to the
northwest and away from the region, showers and thunderstorms
associated to its trailing edge are forecast to affect the
forecast area from east to west on Sunday. As this feature moves
away, a patch of relatively drier air will quickly filter in and
hold over the region late Sunday night through Monday. Although conditions
are expected to somewhat improve during this period, locally
induced convection is expected on Monday afternoon. The next
moisture and instability enhancer is expected late Monday night
with the arrival of the next tropical wave or potential tropical
cyclone. So far, widespread shower and thunderstorm activity is
expected on Tuesday and Wednesday, decreasing on Thursday as the
system moves northward and away from the forecast area.


&&

.AVIATION...SHRA over PR during the morning will affect the local
terminals through at least 19/14Z. The SHRA could cause moments of
MVFR conds with VIS at 3 SM and CIGS below FL030 at times. BKN-OVC
Sky expected today across the local terminals, mostly at around
FL060. SHRA/TSRA expected across NW-PR could cause MVFR conds at
TJBQ after 19/18Z. Winds from the ESE at 10-15KT with sea breeze
variations expected.


&&

.MARINE...A series of swells will maintain hazardous marine
conditions through the upcoming weekend. That is, seas up to 7
feet across the Caribbean waters and Anegada Passage, while seas
of 10 feet or higher are expected across the Atlantic waters and
Mona Passage. The first swell from the north-northwest, associated
to Hurricane Humberto, will spread across the local waters through
at least Friday and possibly into the weekend. This will be
followed by another swell resulting from the passage of Tropical
Storm Jerry to the north as a hurricane on Saturday. As a result,
Small Craft Advisories are in effect.

Given these hazardous conditions, a High Surf Advisory and a
Coastal Flooding Advisory are in effect. High surf is expected
from southwestern Puerto Rico along the west to north coast
through the northeast, as well as Culebra and the northern U.S.
Virgin Islands due to breaking waves between 10 to 14 feet.
Coastal flooding possible across northern Puerto Rico. The best
timing for inundation will be around high tide, which will occur
around noon and again around midnight.

In addition, a High Rip Current risk is in effect for beaches
along the west and north coast of Puerto Rico, as well as beaches
along the north coast of Culebra, Vieques, and the U.S. Virgin
Islands.

Please refer to the latest Coastal Hazard Message (CFWSJU) and
Marine Weather Message (MWWSJU) for the latest information.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 90 80 92 80 / 30 30 50 50
STT 89 80 90 79 / 30 20 50 50

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
513 AM AST Fri Sep 20 2019

.SYNOPSIS...Hazardous marine conditions are expected to hold
through the weekend due to a series of northerly swells affecting
the local waters. As a result, a High Rip Current Risk, as well as
Small Craft, High Surf and Coastal Flooding Advisories remain in
effect. A wetter weather pattern is expected through most of the
forecast period. This will be the result of Hurricane Jerry`s
outer bands today through Sunday, followed by the arrival of a
potent tropical wave or potential tropical cyclone late Monday
night through the end of the workweek.


&&

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

Showers and isolated thunderstorms resulting from an upper trough
west of the local area affected the western waters of our forecast
area, but it has been gradually improving as the night progressed.
This upper trough is expected to continue moving west today and an
upper high pressure will move in over the local area. That said, the
latest high resolution guidance suggests that showers and
thunderstorms will develop across NW-PR this afternoon, but some
forecast models also indicate some activity across eastern PR,
likely due to the decrease in wind speed causing convection much
further east than normal. Hurricane Jerry is expected to pass at
around 200 miles or more north northeast of the local islands late
tonight and Saturday, but the local winds will diminish greatly this
afternoon into Saturday. With that, there is a possibility of an
outer band to move in late tonight into early Saturday, which could
cause showers and thunderstorms across the local islands, including
the USVI.

The local wind flow on Saturday will become southerly as the day
progresses, even though is expected to be on the lighter side. This
southerly wind flow will combine with the available moisture and
local effects to cause the development of showers and thunderstorms
across central to northern Puerto Rico on Saturday afternoon. Then on
Sunday, another band of moisture could move in the morning, bringing
some shower activity. Then drier air expected to move in on Sunday
afternoon, but the local effects could play a role in developing
some shower and thunderstorms across northwestern PR.

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

Model guidance continues to suggest that a wetter pattern will
dominate the region through most of the workweek. But first, a
decrease in shower and thunderstorm activity due to a drop in
moisture content and the entrance of suspended Saharan dust in
the wake of Hurricane Jerry is expected on Monday. Nevertheless,
locally induced showers and possible isolated thunderstorms can be
expected in the afternoon.

The next moisture and instability enhancer, a potent tropical
wave, is expected to approach the region late Monday night into
Tuesday. As of 2 AM AST, this wave was located about 700 miles
east of the Windward Islands, and some development is possible
while it approaches and moves across the Windward Islands during
the weekend. As a result, the National Hurricane Center gives
this system a 30% chance of developing into a tropical cyclone in
5 days. Regardless of its development, model guidance suggests
that the bulk of this system will affect the region Tuesday and
Wednesday, while its trailing edge is expected to move across the
area on Thursday through at least Friday.


&&

.AVIATION...VCSH expected across the local terminals today, but the
activity will be brief and is not expected to have a significant
impact on the local terminals. However, SHRA/TSRA development after
20/16Z expected across NW-PR that is expected to cause at least VCTS
at TJMZ and TJBQ, but it is possible also at TJSJ. Winds will be
from the E-ENE through the day with sea breeze variations after
20/13Z, but winds will become much lighter and variable at times
after 20/22Z. SHRA/TSRA activity could affect the local area once
again after 20/22Z, but this time possibly affecting the USVI.


&&

.MARINE...A series of northerly swells, generated by Post-Tropical
Cyclone Humberto and Hurricane Jerry, will affect through the
upcoming weekend, maintaining hazardous marine conditions. As a
result, Small Craft Advisories are in effect for all but Caribbean
waters due to seas peaking between 7 and 10 feet today. By
tonight, seas are expected to increase up to 14 feet across the
outer Atlantic waters. Winds will range between 5 to 15 knots, but
variable as Hurricane Jerry moves north of the forecast area.

The long period swell will cause breaking waves of 10 to 15 feet
and life threatening rip currents for the beaches along the
western, and northern coast of Puerto Rico, northern Vieques,
Culebra, St.Thomas and eastern St. Croix through Sunday. In
addition, coastal flooding will be possible along the coastal
sections of northern Puerto Rico through this evening.

Please refer to the latest Coastal Hazard Message (CFWSJU) and
Marine Weather Message (MWWSJU) for the latest information.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 92 77 91 78 / 40 40 60 60
STT 91 82 88 82 / 40 30 30 50

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
547 AM AST Sat Sep 21 2019

.SYNOPSIS...Hazardous marine conditions are expected to hold
through at least Sunday due to the combination of two northerly
swells affecting the local waters. Relatively fair weather
conditions are expected today, but Tropical Storm Jerry`s outer
bands will enhance showers activity on Sunday. Model guidance
continues to suggest that a wetter weather pattern will prevail
on Tuesday and continuing through the end of the workweek. This
will be the result the arrival of a potent tropical wave or
potential tropical cyclone (Invest 99L) on Tuesday into Wednesday.
Moisture associated to this system could affect the region through
at least Sunday, before the next tropical wave approaches the
region by Saturday.


&&

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

Scattered showers resulting from the outer bands of Hurricane Jerry
affected the local waters late tonight and will continue through the
morning hours. In the current forecast track, Hurricane Jerry is
expected to pass roughly 200 miles north of the northern USVI, and
even further north from Puerto Rico as Jerry continues moving to the
WNW today. The main impacts expected today are a southerly wind
flow, a gradual increase in moisture, and hazardous marine and surf
zone conditions, which we will have more details in the marine
portions of the discussion. The local wind flow will have a strong
southerly component today and could be somewhat light at around 10
mph or less, with sea breeze variations. Because of this the
afternoon showers and possible thunderstorm activity is expected to be
in the north central to northwestern PR, while isolated to scattered
showers are expected elsewhere. The available moisture and shower
activity is expected to increase late today into Sunday, which could
bring showers and thunderstorms in and around the USVI as well as
eastern PR and the local waters, with the shower and thunderstorm
activity moving to west northwest Puerto Rico on Sunday afternoon
with winds having shifted to an ESE direction by then.

After the moisture associated with Jerry moves away by late Sunday,
drier air will make a return to the local area and we expect a brief
break in shower activity on Monday morning. However, by the
afternoon hours, showers and thunderstorms could develop across the
northwestern quadrant of Puerto Rico as well as showers will start
moving in from the southeast into the local waters and USVI,
associated with a strong tropical wave currently known as Invest
99L. The shower and thunderstorm activity will gradually increase
through the night on Monday into early Tuesday, affecting areas in
and around the USVI and eastern PR.

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

Model guidance has not changed much and favors a wetter weather
pattern due to the passage of a potent tropical wave or potential
tropical cyclone across the region. As of 2 AM AST, this wave was
located several hundred miles east of the Windward Islands with a
40/50% chance of developing into a tropical cyclone in 2/5 days.
Regardless of development, heavy rainfall is anticipated over the
region. If this system develops into a tropical cyclone, it could
bring tropical storm or hurricane conditions to the local islands
Tuesday afternoon into Wednesday. Once this system moves into the
Atlantic waters and north of the local islands, both GFS and
ECMWF models suggest that moisture associated to its trailing
edge will sink south under the influence of a northerly flow of a
deep- layer high moving off the eastern coast of the United States
into the western Atlantic. This moisture will hold across the
region and affect the local islands through at least Friday,
resulting in enhanced shower and thunderstorm activity. Although
there is high uncertainty, the next tropical wave is expected to
approach the region by Saturday.


&&

.AVIATION...VCSH expected across the local terminals this morning
for the USVI terminals as well as TJSJ, but the activity will be
brief and is not expected to have a significant impact. However,
SHRA/TSRA development after 21/16Z is possible across NW-PR that
could cause cause VCSH/VCTS at TJBQ. Winds will be from the SSE at
around 10 KT through the day with sea breeze variations after
21/13Z. Localized NNW winds at TJBQ are possible today, which could
cause a direct crosswind to the runway, but wind speeds are expected
to be at around 10 KT.


&&

.MARINE...The combination of two northerly swells, generated by
Extratropical Cyclone Humberto and Tropical Storm Jerry, will
affect through at least Sunday, maintaining hazardous marine
conditions. As a result, Small Craft Advisories are in effect for
all but Caribbean waters due to seas up 14 feet today. Winds will
range between 5 to 15 knots, but will become variable as Jerry
pass north of the forecast area.

The long period swell will cause breaking waves of 10 to 16 feet
and life threatening rip currents for the beaches along the
western, and northern coast of Puerto Rico, northern Vieques,
Culebra, St.Thomas and eastern St. Croix through Sunday. In
addition, coastal flooding will be possible along the coastal
sections of northern Puerto Rico through this evening.

Please refer to the latest Coastal Hazard Message (CFWSJU) and
Marine Weather Message (MWWSJU) for the latest information.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 91 80 90 80 / 40 60 60 10
STT 89 81 89 82 / 40 50 50 10

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
544 AM AST Sun Sep 22 2019

.SYNOPSIS...Tropical Storm Jerry`s outer bands will bring shower
and thunderstorm activity today. A brief lull in the shower
activity is expected on Monday as drier air will make a return to
the local area. However, Tropical Storm Karen could bring
tropical storm conditions to the local area late Monday into
Tuesday. Flooding rain and tropical storm force winds are the main
potential impacts expected with this storm. Trailing moisture
associated to Karen could affect the region through at least
Saturday. Another brief lull in shower activity can be expected
on late Saturday night into Sunday, but model guidance suggest
that the next tropical wave will approach the local area by Sunday
night.


&&

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

Outer bands of Tropical Storm Jerry can affect the local area this
morning with showers and thunderstorms around the USVI and eastern
PR as well as the local Atlantic and Caribbean waters. This band of
showers will continue moving west, affecting at least the eastern
half of Puerto Rico and the USVI, but the latest guidance insists on
weakening it late in the morning. If the guidance is correct and the
band of showers weakens and clears up, the local effects and
available moisture will combine to cause showers and thunderstorms
across the northwestern sections of PR, while isolated to scattered
showers would be expected elsewhere.

For Monday, a brief lull in the shower activity is expected as drier
air will make a return to the local area. However, by the afternoon
hours, showers and thunderstorms are expected to develop across the
northwestern quadrant of Puerto Rico as well as showers that will
start moving in from the southeast into the local waters and USVI,
associated with the first bands of the newly formed Tropical Storm
Karen. The shower and thunderstorm activity will gradually increase
through the night on Monday and continue through Tuesday,and
lingering until early Wednesday, affecting most of the local islands.

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

Model guidance has not changed much and continues to favor a
unsettled weather pattern due to trailing moisture from Tropical
Storm Karen holding over the region through at least Saturday.
Both GFS and ECMWF models agree that as tropical moisture
continues to pull northward, precipitable water values will remain
at or above 2.0 inches each day. As a result, periods of moderate
to heavy rainfall can be expected each day, particularly during
the afternoon hours. There is medium confidence in this forecast
since there are uncertainties in the evolution of Tropical Storm
Karen after it moves over the Atlantic waters and away from the
region by Wednesday into Thursday. Weather conditions may briefly
improve late Saturday into Sunday as an area of relatively drier
air moves in. However, the next tropical wave and associated
moisture is expected to approach the region by late Sunday.


&&

.AVIATION...VCSH/VCTS expected across TJSJ and the USVI terminals
early this morning as a band of SHRA/TSRA affect the local area.
Winds will be light and variable through around 22/15Z then east to
east southeast winds of around 10 knots will be observed across the
local area, with sea breeze variations. SHRA/TSRA expected across NW-
PR after 22/18Z which could cause VCTS at TJBQ.


&&

.MARINE...Although a northeasterly swell from Tropical Storm Jerry
will continue to diminish today, hazardous marine conditions with
seas up to 7 feet will continue through early next week across the
Atlantic waters and local passages. As a result, Small Craft
Advisories are now in effect for these marine zones. There is a
High Rip Current Risk in effect for beaches along the north coast
of Puerto Rico, Culebra and Saint Thomas.

Please refer to the latest Coastal Hazard Message (CFWSJU) and
Marine Weather Message (MWWSJU) for the latest information.

Marine and surf zone conditions are expected to deteriorate once
again late Monday night into Tuesday as Tropical Storm Karen
approaches the local area.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 92 80 90 79 / 40 10 30 60
STT 89 81 89 79 / 50 10 50 70

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
448 AM AST Mon Sep 23 2019

.SYNOPSIS...Weather conditions are forecast to start deteriorating
later this evening and into the overnight hours as the outer rain
bands associated with Tropical Storm Karen approaches the local
area. The worst weather conditions are expected on Tuesday as the
tropical storm is forecast to track northwards across the area
based on the latest forecast from the National Hurricane Center.
Widespread heavy rainfall with accumulations between 2 and 4
inches with isolated higher amounts of up to 6 inches will remain
possible at this time. This will result in flooding across many
areas as well as mudslides in areas of steep terrain. Winds up to
tropical storm force are possible mainly across the eastern third
of Puerto Rico, Vieques, Culebra, and the U.S. Virgin Islands.

&&

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

Mainly tranquil weather conditions are expected to continue through
at least early this evening across the area as a dry slot moves
overhead. Therefore, shower activity is expected to be quite
limited across most of the area. However, showers and isolated
thunderstorms may develop across northwest Puerto Rico this
afternoon as the available low-level moisture combines with
daytime heating and sea breeze convergence.

The main weather concern during the short-term period will be
Tropical Storm Karen. The latest forecast from the National
Hurricane Center continues to bring Karen over Puerto Rico as a
minimal tropical storm. As Karen approaches from the south late
Monday night into Tuesday, shower and thunderstorm activity is
expected to increase in coverage with the heaviest rainfall activity
expected during the day on Tuesday. At this time, widespread
rainfall accumulations between 2 and 4 inches with isolated higher
amounts of up to 6 inches are expected. The heaviest rainfall activity
is expected across the southern and eastern half of Puerto Rico
as well as across the U.S. Virgin Islands. Rainfall of this magnitude
is expected to result in urban and small stream and river flooding
as well as mudslides and rockfalls in areas of steep terrain. In
addition to the rainfall activity, winds up to tropical storm force
are possible across the eastern third of Puerto Rico, Culebra,
Vieques, and the U.S. Virgin Islands.

Even though Karen is expected to move away from the area by early
Wednesday, sufficient moisture is expected to linger over the
area that additional shower and thunderstorm activity is expected
across the area, mainly across portions of eastern PR and the
USVI.

Given the expected rainfall and wind threat, a Flash Flood watch and
a Tropical Storm Warning is in effect for the entire forecast area.

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

The long-term period still looks to be very unsettled as a result
of tropical moisture accompanying and trailing Tropical storm
Karen as it lifts northwards across the region. TS Karen is
forecast to be north of Puerto Rico by Thursday, however it will
continue to pull moisture from the deep tropics across Puerto Rico
and the U.S. Virgin Islands through the end of the work week. The
south to southwest wind flow coupled with significant moisture
pooling will result in periods of moderate to heavy rainfall, and
brief gusty winds each day especially during the afternoon and
early morning hours.

Recent model guidance continued to suggest a shift in the winds
late Friday through Saturday, becoming more east to northeasterly
ahead of another tropical wave expected to move across the region.
This feature will bring another surge of tropical moisture to the
region and therefore maintain a fairly moist and unstable weather
pattern Saturday through Sunday. The potential for urban and small
stream flooding as well as mudslides in areas of steep terrain
will therefore remain possible over the weekend. A gradual drying
trends with more stable conditions is expected by Monday, but
residual moisture along with local effects and daytime heating
will still yield to isolated to scattered afternoon showers and
thunderstorms mainly over parts of the interior and west sections
of Puerto Rico. Lesser activity is forecast for the USVI during
that time.

&&

.AVIATION...Mainly VFR conditions are expected to prevail across all
terminal sites through at least 23/14z. VCTS expected across the
Leeward Island terminals after 23/15z as the rainbands associated
with TS Karen approach the area, with MVFR/brief IFR conditions
possible. SHRA/TSRA expected across western PR between 23/16z and
23/22z, possibly affecting the vicinity of TJMZ and TJBQ. Winds
light and variable overnight, increasing to 10 to 20 kts from the
E-ESE with sea breeze variations developing after 23/14z.

&&

.MARINE...Seas will remain up to 7 feet across the outer Atlantic
and Caribbean waters and Anegada passage during the rest of the
day. Marine conditions are forecast to continue to deteriorate
once again by tonight as Tropical Storm Karen approaches from the
south, with seas greater than 8 feet expected. These hazardous
seas are expected to last through late Tuesday night. A high risk
of rip currents is expected to continue across the northern beaches
of Puerto Rico and Culebra, with a moderate risk expected elsewhere
today. &&

.PRELIMINARY POINT TEMPS/POPS...
SJU 91 80 88 75 / 30 80 80 80
STT 89 82 84 78 / 50 90 90 80

[msbee]

Good morning Luis
THank you for your regular updates.
I am hoping that PR is spared from any serious damage.
Good luck and stay safe.

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
418 AM AST Tue Sep 24 2019

.SYNOPSIS...
Increasing cloud cover and better organized convection were noted
over the eastern Caribbean waters in association with Tropical
Storm Karen. Doppler weather radar and recent satellite imagery
continue to show explosive deep convection associated with Karen
becoming more widespread and increasing over the past few hours.
Convective outflow and rainbands were also noted propagating
northwards and reaching parts of the islands from time to time.
Expect this activity to continue to increase and become more
frequent as Karen tracks north northwest across the forecast area
during the rest of the day into Wednesday.

A Flash Flood Watch remains in effect until Wednesday afternoon
for Puerto Rico and the U.S. Virgin Islands.

A Tropical Storm Warning is also in effect for Puerto Rico and
the U.S. Virgin Islands.

&&

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

The first rainbands of Karen were noted moving across the local
waters, with some of them making their way inland, overnight.
This activity is expected to continue and then to increase in
frequency and intensity as Karen moves closer during the morning.
GOES imagery and the Hurricane Hunter aircraft detected deep
convection increasing south of it center. The center of Karen is
still expected to move over or near Puerto Rico and the U.S.
Virgin Islands today. In the latest National Hurricane Center
intensity forecast, Karen makes landfall as a weak tropical storm
system. The main impacts associated with Karen are flooding
rains, winds, and hazardous marine conditions. Even though the
center of Karen will be over the Atlantic waters near northeast
Puerto Rico by this afternoon, flooding rains will likely continue
across PR and USVI through at least Wednesday. Therefore, a Flash
Flood Watch will be in effect until at least Wednesday evening.

Regardless of Karen`s intensity, the system is expected to produce
rainfall accumulation totals between 2 and 4 inches of rain, with
isolated rainfall amounts up to 8 inches possible, mainly across
the southern and eastern sections of Puerto Rico, including the
mountainous terrain, Vieques, Culebra and the U.S. Virgin Islands.


Based on the latest model guidance, a wet pattern will persist over
Puerto Rico and the U.S. Virgin Islands through at least Thursday
with Total Precipitable Water values ranging between 2 and 2.5
inches.

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

Moisture remnants from Tropical Storm Karen are forecast to be
gradually lifted north of the area by Friday; however, due to its
proximity, it will maintain a light southerly wind flow across
the area through Friday. This in turn will support a fairly moist
airmass persisting across the region and therefore favor the
development of afternoon convection across the islands. The next
tropical wave is forecast to push into the region Saturday through
Sunday, followed by decreasing moisture and improving weather
conditions on Monday and Tuesday.

Tropical Storm Lorenzo, which formed yesterday south of the Cape
Verde Islands, is currently forecast by the National Hurricane
Center to cross 20 north Saturday morning. This will be more than
1200 miles east of Puerto Rico, and this storm is currently not
expected to pose any direct threat to Puerto Rico or the U.S.
Virgin Islands.

&&

.AVIATION...VCSH/VCTS expected en route between PR and the Northern
Leeward Islands as the rainbands associated with TD Karen approaches
the area. Brief MVFR SCT-BKN lyrs nr FL022...FL050...FL090. Winds
light and variable bcmg...10-20 kts fm E-ESE with sea breeze
variations aft 24/14z. Please refer to the latest SIGMET as well as
NHC Advisory for TD KAREN.


&&

.MARINE...The recently upgraded TS Karen continues to track NNW
across the local Caribbean waters. Deteriorating seas and hazardous
marine conditions with squally conditions will be likely mainly
across the Caribbean waters and local passages. A tropical storm
warning remains in effect.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 90 76 91 78 / 80 80 60 50
STT 86 80 87 80 / 80 80 60 60

[cycloneye]

Area Forecast Discussion...UPDATED
National Weather Service San Juan PR
657 AM AST Wed Sep 25 2019

.UPDATE...Tropical Storm Karen pushed over the waters just east of
Puerto Rico around Culebra and Vieques and is now in the offshore
Atlantic waters north of the forecast area. At 5 AM AST Tropical
Storm Karen was at 20.5 N latitude and 65.2 W longitude or about
155 miles north northeast of San Juan Puerto Rico. It is moving
north at 14 mph. Showers were seen in the latest radar images
south and southwest of Saint Croix while wide swaths of general
rain were moving north northeast across the Atlantic north of
Puerto Rico and in the Anegada Passage. Showers were also moving
into Puerto Rico over Lajas.

&&

.PREV DISCUSSION... /issued 642 AM AST Wed Sep 25 2019/

SYNOPSIS...
Tropical Storm Karen was centered near 19.1N 65.0W at 1100 PM
AST...25/0300 UTC, or about 85 nm NE of San Juan Puerto Rico, and
about 50 N of St Thomas, moving NNE at 14 MPH. Maximum sustained
winds are near 45 MPH and minimum central pressure is 1002 mb.
Karen`s squalls and rainbands will continue to affect Puerto Rico
and the Virgin Islands before it pulls away to the north of the
islands later today. Trailing moisture lifted northward across the
region by Karen will maintain a moist and unstable environment
through then end of the work week. This will support afternoon
showers and isolated thunderstorm development each day.

SHORT TERM...Today through Friday...The center of Tropical Storm
Karen was now northeast of Puerto Rico and north of the northern
U.S. Virgin Islands. Recent information from the National Hurricane
Center indicated that Karen will continue to move toward the north-
northeast and farther away from the region during the rest of the
day. However Karen will continue to lift copious amounts of tropical
moisture across the region through Thursday and therefore maintain
a very moist and unstable environment. Consequently...expect
periods of showers and isolated thunderstorm activity to affect
the islands and coastal waters along with occasional squalls
generated from the rainbands associated with Karen. On Thursday
and Friday a fairly light east to southeast wind flow will prevail
with still a fairly moist environment expected across the region.
That said...expect local effects and daytime heating to be more
than sufficient to favor afternoon convection each day across the
islands. Furthermore, soils will remain saturated due to previous
days` rainfall, and any additional rain will cause urban and small
stream flooding as well as mudslides in areas of steep terrain.
Recent guidance continued to suggest precipitable water values
well 2.0 inches through Thursday, then gradually diminishing by
late Friday.

LONG TERM...Saturday through Thursday...

Based on the latest intensity forecast from the National
Hurricane Center (NHC), Tropical Storm Karen is forecast to be
somewhere above latitude 25 N and east of longitude 60 W by
Saturday. Karen is forecast to reverse its track westward, as
interacts with a strong high pressure over the eastern Atlantic
and with Lorenzo, which is forecast to be a Major Hurricane.
Karen`s track will result in a southerly wind flow across the
islands through at least early next week. Also, this brings in a
tropical wave toward the area by Tuesday and Wednesday. This moist
airmass will be followed by a relatively drier air during the
second part of the upcoming week.

That said, and if model guidances are correct, a relatively wet
pattern with warm to hot heat indices will persist through at least
early next week. Then, drier conditions with hazy skies after mid-
week of the upcoming week.

AVIATION....Aviation...Tropical Storm Karen now centered just
north of the flying area but continued to lift deep convection
with SHRA/TSRA ovr most of the local terminals. Multi-Lyrs SCT-BKN
nr FL025...FL050... FL090...BKN-OVC btw FL200-FL250. Brief MVRF
/psbl IFR conds due to SHRA/Low CIG with MTN Top obscr along Ctrl
MTN range of PR til 25/12Z. SHRA/VCTS psbl at all terminals but
VFR conds fcst to prevail til 25/12Z. Winds 10-20 kts and higher
gust btw 30-40kts with rainbands from Karen. Please see latest NHC
advisory for Tropical Karen.

Marine...
Seas will continue to improve today across the local waters as Karen
continues to move northward away from the region. Therefore, expect
seas below 5 feet and winds around 15 knots across most of the local
waters through at least the upcoming weekend. Then, an easterly
swell associated with Lorenzo is forecast to increase the seas
across the local Atlantic waters Sunday into the upcoming week.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 88 78 91 79 / 60 40 60 50
STT 87 80 86 80 / 60 60 60 50

[StormingB81]

How’s everyone doing in the islands?