Caribbean - Central America Weather

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cycloneye
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Re: Caribbean - Central America Weather (Watching INVEST 96L)

#19661 Postby cycloneye » Tue Nov 13, 2018 9:42 am

A Flash Flood Watch has been issued from Tuesday thru Thursday.

Image
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Re: Caribbean - Central America Weather (Effects of strong tropical wave in NE Caribbean)

#19662 Postby cycloneye » Tue Nov 13, 2018 4:52 pm

Area Forecast Discussion
National Weather Service San Juan PR
548 PM AST Tue Nov 13 2018

.SYNOPSIS...An active tropical wave interacting with an upper
level trough will result in scattered to numerous showers and
thunderstorms across the region during the next few days. Unstable
weather conditions are expected to continue through at least
Friday. A mid to upper level ridge will build from the northeast
during the weekend, promoting fair weather conditions through
early next week.


&&

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

A flash flood watch is in effect through at least thursday
afternoon for Puerto Rico and the U.S. Virgin Islands. Scattered
convection across the USVI and eastern PR left between 1-2 inches
of rain today. Minor urban flooding was reported today over
portions of eastern PR. An area of strong thunderstorms persisted
over the offshore Caribbean waters just to the south and east of
St. Croix, some of this activity is expected to affect St. Croix
through the evening hours. Breezy conditions will continue with
winds ranging between 15-25 mph, with the higher winds remaining
across the offshore waters.

As the wave axis continues to approach the region from the east
and cross the islands on Wednesday...additional showers and
thunderstorms are expected to increase overnight into Wednesday
morning across the USVI and the eastern portions of PR. Based on
the latest guidance, the heaviest shower activity is expected
between early Wednesday morning through Wednesday evening across
the islands. Rainfall accumulations in general should range
between 1-4 inches with isolated higher amounts through the short
term period.
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Re: Caribbean - Central America Weather

#19663 Postby cycloneye » Wed Nov 14, 2018 4:54 am

Area Forecast Discussion
National Weather Service San Juan PR
529 AM AST Wed Nov 14 2018

.SYNOPSIS...Unstable pattern associated with a surface trough and
an upper level low will continue to produce periods of heavy
rainfall across the local islands through Thursday. Conditions
will gradually improve Friday as mid-level high pressure ridge
will limit the coverage and the vertical development of the
showers. A moisture surge embedded in the trade winds will bring
some passing showers on Saturday.

&&

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

The interaction of a low level trough over the area with an upper
level low spread from Haiti to just west of Saint Croix and
abundant moisture will cause shower and thunderstorms to continue
across the area. Southeast flow of 20 to 30 knots will keep a flow
of moisture over the local area with southeast Puerto Rico
receiving a major portion of the rainfall, but with northwest
Puerto Rico receiving some afternoon showers due to local
convergence and heating. A dry slot at 700 mb will enter the area
around 15/12Z, but will be followed by another band of good
moisture and a ribbon of moisture that will arrive from the east
southeast on Friday.

The low pressure in the upper levels appears to have disrupted the
formation of a tropical system and the National Hurricane Center
continues to give it a dismal chance of becoming a tropical storm in
the next 5 days. Also the wave has a classic inverted vee formation,
the first leg of which is over Puerto Rico and the Atlantic waters
to the north. This is why Saint Thomas and Saint Croix received so
little rain overnight. The second leg should arrive tonight--or a
little earlier in the case of the U.S. Virgin Islands. But after
this leg goes by, the southeast flow that continues will bring bands
of high humidity through the area and more narrow bands of drier air
and subsidence that will keep shower formation likely through the
period.

A flash flood watch continues in effect for all of Puerto Rico and
the U.S. Virgin Islands. Local rains of 1 to 4 inches, the exact
location being difficult to ascertain, are expected today through
Thursday and would produce flooding. Nevertheless, widespread
flooding is not expected.

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

Another upper level low/TUTT will approach the region from the
east. This feature is forecast to remain over the Leeward Islands
keeping the local area on the stable side of the trough during
the weekend. However, a moisture surge embedded in the easterly
trade winds will bring showers and a couple of thunderstorms at
times during the weekend.

By early next week...Mid level ridge will hold and dominate the
local weather conditions. This will strengthen the trade wind cap
favoring a decrease in shower and thunderstorm activity. Under
this pattern, fresh trade winds will carry some showers over the
USVI and eastern PR in the morning followed by the typical
afternoon convection over western PR.

&&

.AVIATION...An upper lvl low and slowly migrating trough has produced
a wide area of rain, MVFR and mtn obscurations that covered the
eastern quarter of PR at 14/09Z with only isolated showers over
other land areas. Sct-numr showers will persist over the Atlantic
waters. SHRA over land will dvlp after 14/14Z and spread west. By
14/16Z SHRA/TSRA are expected to dvlp ovr wrn and interior PR.
SHRA/TSRA will also be present around the Leeward Islands.
Unsettled conds will prevail thru 16/18Z in the fcst area. Sfc
winds ESE 10-20 kt with some sea breeze influences aft 14/14Z. Max
winds blo FL540 are ESE-SE and are all are blo FL100 at 15 to 25
kt.

&&

.MARINE...Breezy conditions will likely prevail the rest of the
week, resulting in choppy conditions across most of the regional
waters. As a result, Small Craft Advisories are in effect for most
of the local waters through at least the end of the work week. Seas
should range between 6-8 feet occasional up to 10 feet offshore,
and between 3-6 feet elsewhere.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 88 76 88 76 / 90 60 40 40
STT 86 76 86 78 / 70 50 50 50
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Re: Caribbean - Central America Weather

#19664 Postby cycloneye » Thu Nov 15, 2018 5:32 am

Area Forecast Discussion
National Weather Service San Juan PR
607 AM AST Thu Nov 15 2018

.SYNOPSIS...Drier air mass will move over the local islands today.
As a result, the shower and thunderstorm coverage should be less
than yesterday. Another surge of moisture will increase the
potential for showers and thunderstorms again during the weekend.

&&

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

An intense surface low (947 mb) east of Newfoundland will push a
1024 mb high to 1000 miles northeast of Punta Cana or 900 miles from
San Juan, Puerto Rico. This will keep surface and low-level flow
mostly east with a weak southerly component and serve to bring bands
of moisture out of the western tropical Atlantic separated by some
very dry patches of air.

The MIMIC product shows the first dry band now pushing across the
northern end of the Leeward Islands into the U.S. Virgin Islands.
Currently the GFS has 850 mb dry pocket about 200 miles southeast
of the driest air at 700 mb making exact timing more difficult.
But using precipitable water as a proxy, expect drying to begin
around 8 AM AST over the U.S. Virgin Islands and noon on the east
coast of Puerto Rico. This drier air will take its greatest toll
on convection between 8-10 kft even though the GFS suggests that
convection should be able to rise unimpeded to 44 kft. The drier
layer should also mean an early end to convection in the western
half of Puerto Rico this afternoon as well. Before this happens
though, heavy showers and isolated thunderstorms should develop
over western Puerto Rico. Although the threat of flash flooding is
now considered over, and the Flash Flood Watch has been
cancelled, urban and small stream flooding is expected in western
Puerto Rico and mudslides cannot be ruled out.

A second band of moisture moves through the area between 16/00-12Z
and another round of showers will cross mainly eastern Puerto
Rico in the morning hours on Friday. Friday afternoon also looks
very wet with rainfall totals exceeding two inches in some areas.
The moisture that continues to flow northwest into Puerto Rico
will peak again just after noon on Saturday for yet another round
of heavy rainfall for Puerto Rico. Drying begins immediately
afterwards.

Influence from the upper level trough and instability over the area
will gradually wane through the period, but convection Thursday
night (where it forms), Friday night and Saturday could gain a weak
boost due to upper level divergence.

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

Mid level ridge will build and dominate the local weather
conditions Sunday into early next week. At upper levels, a TUTT
low will establish just northeast of the Leeward Islands. Both
features favors the erosion of mid-upper level moisture across
the local region. This will likely result in fair weather
conditions across Puerto Rico and the U.S. Virgin Islands.
However, trade wind showers will continue to reach portions of the
U.S. Virgin Islands and eastern Puerto Rico at times but the
frequency will be low. With mid level temperatures rising due to
the presence of the ridge, only a couple of thunderstorms will
form over western Puerto Rico each afternoon. This typical
pattern will likely persist through most of next week.

&&

.AVIATION...Bands of moisture will pass through the area, but drier air is
expected to improve flying conditions today compared to the last
several days. VFR conditions are expected to prevail until
SHRA/isold TSRA dvlp over wrn and interior PR aft 15/16Z with mtn
obscurations. SHRA will dissipate over these area aft 15/22Z but
some SHRA will return to the USVI/ern PR and the Leeward Islands aft
16/00Z. Sfc winds will be ESE at 12 to 18 knots with some sea breeze
influences. Max winds WNW 30 kt at FL410 by 16/06Z otherwise maximum
winds ESE 20-25 kt btwn FL030-090.

&&

.MARINE...Breezy conditions have resulted in choppy conditions
across most of the regional waters. As a result, Small Craft
Advisories are in effect for most of the local waters through at
least Saturday. Mariners can expected seas of 6-8 feet with
occasional up to 10 feet across the offshore waters and between
3-6 feet elsewhere. Also, a high risk of rip currents continue for
the north facing beaches of Puerto Rico and Culebra as well as
the east coast beaches of St. Croix.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 87 76 87 77 / 40 50 50 60
STT 86 79 85 78 / 20 50 70 50
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Re: Caribbean - Central America Weather

#19665 Postby cycloneye » Fri Nov 16, 2018 5:24 am

Area Forecast Discussion
National Weather Service San Juan PR
532 AM AST Fri Nov 16 2018

.SYNOPSIS...Low level moisture will increase somewhat across the
local islands today and Saturday as a wind surge propagates
across the Northeast Caribbean region. This feature will likely
increase showers activity across the U.S. Virgin Islands and
Puerto Rico from time to time. A drying trend is forecast next
week as a mid-upper level ridge will bring drier and more stable
air aloft.

&&

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

High pressure weakens and settles into the central Atlantic Ocean
from out of Maine yesterday. This will maintain easterly trade wind
flow that will be enhanced by a wind surge and pulse of moisture.
That moisture is visible as an arc of precipitable water of greater
than 2 inches that developed and moved into the Leeward Islands
overnight. The GFS is in agreement with model runs from yesterday--
at least qualitatively. It brings that higher moisture through
Puerto Rico today and tonight, with the best moisture over San Juan
by 17/00Z. The pulse of moisture and the low-level convergence the
wind surge will bring bodes well for showers to increase during the
day. Working against this, the GFS sounding does show a layer of
relatively dry air (less than 15 percent between 14-15 kft) at
16/18Z with precipitable water still at a hefty 1.88 inches. This is
an increase from the 1.77 inches measured in the 16/00Z sounding,
but the layer cuts the convective potential and limits instability
where the lapse rate becomes more stable, which will limit the
amounts of rain that fall when they fall. By 17/00Z, however the
model is showing 1.97 inches of precipitable water and no less than
35 percent in the previously dry layer. Hence, most windward slopes
on the eastern part of Puerto Rico should get some rain before the
evening ends and nearly all of Puerto Rico is expected to get at
least a little rain before then. Western Puerto Rico will also see
very good chances of showers and isolated thunderstorms with the
heating allowed during the morning hours. Expect shower formation
there by 16/16Z. Afternoon and evening rains across the U.S.
Virgin Islands and Puerto Rico respectively, should end rather
abruptly as the model shows precipitable water dropping rapidly
overnight to only 1.2 inches.

Some showers are still possible over the eastern mountains of Puerto
Rico, but the rest of of the island should see a dry Saturday
morning. Then showers and a few thunderstorms become likely in west
northwest Puerto Rico with only isolated to scattered showers
elsewhere under a pulse of moisture more evident at 700 mb. The
drying trend continues into Sunday. Although some moisture is around
during the day, mid levels become quite dry. Most areas outside of
the general area just east of the Rincon peninsula will see only
isolated showers Sunday afternoon. Then later in the afternoon the
GFS shows more moisture moving in from the southeast as fragmented
patches of low level moisture move through the area in rapid
succession. This will generate a few showers, but coverage should be
relatively sparse.

Upper level divergence aloft is very limited during the entire
period and most of the action that occurs will be dependent on
conditions in the lowest levels.

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

Mid to upper level ridge will hold most of the next week, under
generally fair weather conditions. The drier and more stable air
mass at mid-levels will reduce the coverage of the showers and
the probability of thunderstorms. However, weak easterly
perturbation embedded in the trade winds will briefly enhance the
diurnal shower activity Monday and Wednesday when these
pertubations are forecast to move across the eastern Caribbean.
The rest of the week expect typical weather conditions with brief
passing showers over eastern Puerto Rico and the U.S. Virgin
Islands during the morning hours, followed by some afternoon
showers over western Puerto Rico. Winds will gradually diminish as
the week progresses due a weakening of the surface high pressure
over the north central Atlantic. All in all, a drying trend and a
decrease in shower activity is forecast next week under the
influence of a mid-upper level ridge.

&&

.AVIATION...In the Leeward Islands a band of moisture is moving through
bringing brief MVFR CIGS and light showers. VFR is expected there
aft arnd 16/18Z till 17/06Z. A band of moisture is moving into
the USVI, but MVFR conds are expected to be brief--if any-- with
sct SHRA till arnd 16/18Z. SHRA/TSRA will dvlp wrn and interior PR
aft arnd 16/16Z with mtn obscurations and areas of MVFR/IFR til
arnd 16/22Z. Periods of SHRA are expected in most areas of PR till
arnd 17/00Z. Sfc winds E- ESE 10-18 knots with gusts to 26 kt
psbl. Max winds blo FL540 will be 20-26 kt blo FL120 as a low
level wind surge pushes through the area.

&&

.MARINE...Choppy seas will continue through the end of the week
as breezy conditions will likely prevail across the regional
waters. As a result, Small Craft Advisories are in effect for most
of the local waters through Saturday, except for offshore
Atlantic water where choppy conditions will prevail through
Sunday. Mariners can expected seas of 6-8 feet with occasional up
to 10 feet across the offshore waters and between 3-6 feet
elsewhere. Also, a high risk of rip currents continue for the
north facing beaches of Puerto Rico as well as the north and east
coast of St. Croix.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 87 77 87 77 / 80 40 30 20
STT 85 78 86 78 / 70 30 30 30
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Re: Caribbean - Central America Weather

#19666 Postby cycloneye » Sat Nov 17, 2018 5:29 am

Area Forecast Discussion
National Weather Service San Juan PR
507 AM AST Sat Nov 17 2018

.SYNOPSIS...Diminishing moisture will produce less shower activity
today, but some showers are still indicated. Showers and possible
thunderstorms will return Tuesday night and Wednesday with the
next band of better moisture, although some 700 mb moisture will
be present. Shower activity will persist through the end of next
week as a cold front approaches late next week.


&&

.SHORT TERM...Today through Monday...
A somewhat settled weather pattern is progged through the short-term
period with scattered showers across the eastern areas of Puerto
Rico during the morning, then showers over portions of the western
areas during the afternoon.

A drier weather pattern is expected to prevail through Monday. This
is a result of drier air in the mid to upper-levels of the
atmosphere as well as the 850 mb level. This air will move in
from the east later this morning and through the afternoon. The
GFS shows 850 mb to 700 mb relative humidities ranging from 20 to
40 percent. These values are 2 standard deviations below
November`s climatology for San Juan Puerto Rico.

Sunday afternoon low-level moisture will increase over the western
areas of the islands, then another patch of drier air is progged to
rapidly filter in again out of the east. This patch of drier air
will drop relative humidities values to the 25th percentile.
Therefore, showers will be limited again across the area.

A strong ridge of high pressure will maintain it`s hold across the
central Atlantic waters and promote a moderate to fresh easterly
wind flow across the area. At the upper-levels, a weak trough
remains to the northeast of Puerto. This feature will not have
much of an effect on the local weather. Therefore, the short-term
forecast is predicated on the drier air and patches of moisture
that are forecast to move in from the east.

.LONG TERM...Tuesday through Saturday...
High pressure will continue in the west central sub-tropical
Atlantic. Higher pressure will begin to build into the western
Atlantic out of the northeastern United States Friday night and
Saturday of next week. Upper level high pressure will dominate the
weather pattern until Friday and Saturday when a long wave trough
will approach the area. An area of low level moisture will move
into Puerto Rico and the U.S. Virgin Islands from the east
northeast and bring a weak wind surge. This will increase the
showers across the area on Tuesday night and Wednesday. This
showery pattern will continue on and off through the period as
patches of moisture move through. On Friday winds in the lower
levels become nearly calm as a col at the end of an approaching
frontal zone moves into the area. This will increase rain chances
but should keep the best rains over the interior of the island
Friday and Saturday. Due to the shallow nature of the best
moisture rain fall amounts will be light to moderate, though the
lack of good steering winds could leave some heavy showers in one
place for an extended period of time during Friday and Saturday
afternoons and might provoke an episode of local urban and small
stream flooding.

&&

.AVIATION...VFR conds are expected to prevail through the reminder
of the TAF period. Iso SHRA/tsra will develop across terminals
TJMZ and TJBQ by 17/15Z before clearing out by 18/00Z. Sfc winds
out of the east to southeast at 10 to 15 kts with higher gust up
to 25 kts. Maximum winds ESE 25 kt at FL150 and NNW-N 25 kt btwn
FL350-410.

&&

.MARINE...Winds from a passing wind surge have kept seas riled and
seas in the outer Atlantic are still running 6 to 8 feet.
Elsewhere in unprotected waters seas are running 5 to 7 feet.
Although seas of at least 7 feet will persist in the northeast
corner of the outer Atlantic waters through Wednesday, seas in
the other waters should come down overnight tonight.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 87 76 87 76 / 30 30 20 20
STT 86 77 86 77 / 30 30 30 30
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Re: Caribbean - Central America Weather

#19667 Postby cycloneye » Sun Nov 18, 2018 5:00 am

Area Forecast Discussion
National Weather Service San Juan PR
521 AM AST Sun Nov 18 2018

.SYNOPSIS...Moderate trade wind flow will bring scattered showers
to the area under upper level high pressure. A vigorous band of
moisture will increase showers on Wednesday and thunderstorms will
likely return to the interior. Then a cold front will approach the
area and may cross on Saturday.

&&

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

A stable weather pattern will continue to prevail as a result of
limited moisture, a drier air mass and a surface and mid-level
ridge over the area. The drier air mass, the surface and the mid-
level ridges will limit shower development during the afternoon
across most of the forecast area through Tuesday. However moderate
trade winds with embedded moisture will periodically move in from
the east. This could lead to isolated showers--mainly over
portions of the interior and western Puerto Rico during the
afternoon. Tuesday, model guidance shows moisture returning from
the east and to the north of Puerto as a result of a stationary
frontal boundary to the north of the islands. Therefore rain
chance should go up during the middle of the week.

.LONG TERM...Wednesday through Sunday...
At upper levels the ridge over the area will shift to the east
through Thursday. A broad upper level trough will cross through
and north of the area late Friday and pass through the leeward
Islands on Sunday. At the surface and at lower levels a band of
moisture will move through the area on Wednesday, followed by
another pulse on Thursday and Friday. On Saturday surface flow
slows and 700 mb flow becomes southwesterly as a front is forecast
to move into the forecast area and cross through Puerto Rico and
the U.S. Virgin Islands. Confidence is somewhat low on this
crossing as the GFS generally moves fronts too far southeast, so
have tempered the forecast somewhat regarding shower activity.
There is moisture however so POPs will be fairly good until
Sunday. The low level trough also stalls over the area with some
good moisture. Mid and upper level moisture values drop
significantly by Sunday, so rain chances are expected to taper off
then.

&&

.AVIATION...VFR conditions are expected to prevail across TAF sites
through 18/22Z. -SHRA/SHRA are forecast to develop across the
western and interior areas of Puerto Rico, or near terminal sites
TJMZ and TJBQ by 18/17Z. Clearing is forecast to begin around
18/23Z. Winds will continue to prevail from the east to northeast
at 15 to 20 kts with higher gusts possible--on exposed coasts.
Winds back to the east- northeast at 026 to 041 kft ranging from
20 to 30 kts.

&&

.MARINE...Seas will come down some today and all small craft
advisories up previously will come down by 2 PM AST. Small craft
will need to exercise caution afterward. Conditions will
deteriorate briefly in the local Atlantic outer waters Monday
night, but seas are expected to subside on Tuesday.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 87 76 88 77 / 20 20 30 20
STT 86 76 86 77 / 20 30 30 20
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Re: Caribbean - Central America Weather

#19668 Postby cycloneye » Mon Nov 19, 2018 5:41 am

Area Forecast Discussion
National Weather Service San Juan PR
404 AM AST Mon Nov 19 2018

.SYNOPSIS...A surface high pressure located over the central Atlantic
will continue to generate easterly winds across the local region.
Expect increasing moisture associated to a low level disturbance
that is forecast to move across the southern Caribbean waters
between today through Tuesday.


&&

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

Modest high pressure at the surface continues over the central
Atlantic. A ridge of high pressure at upper levels will move across
the area from Haiti to arrive on Wednesday, with north to northwest
flow over the area the entire period. Mid levels are exceptionally
dry (less than 6%) through Wednesday night. This will limit showers
and convection over the area significantly. This morning a band of
moisture begins to generate around 52 west in the easterly flow. It
will strengthen through Wednesday and expand in area as it
approaches Puerto Rico and the U.S. Virgin Islands. It will enter
the forecast area on Tuesday afternoon, spread through the area late
Tuesday and Tuesday night, then leave the area just as quickly on
Wednesday morning. Models show its maximum vertical extent when it
passes over San Juan Tuesday night should be only about 600 mb, so
thunderstorms are not expected. Low level moisture on Wednesday
will probably linger long enough to support good--though shallow--
convection Wednesday afternoon in western Puerto Rico, otherwise
conditions dry rapidly and few showers should be seen. One note,
although models have been consistent with regard to the existence of
this feature, they have steadily advanced its arrival by several
hours in each run as well as weakened it during the last past
several days. This trend may continue.

.LONG TERM...Thursday through Monday...
High Pressure will move closer our local forecast area on Thursday
generating a more stable and drier conditions across the local
region through Friday. After Saturday the forecast will depend how
close the frontal boundary will be to our local forecast area. On
the latest GFS model suggest the highest amount of moisture will
stay over the Atlantic ocean but enough moisture will reach the
local area to increase the chances of showers on Sunday and
Monday.


&&

.AVIATION...VFR conditions are expected to prevail across the
forecast area thru 20/06Z. With exceptions mentioned blo.
-SHRA/SHRA are fcst to dvlp across the wrn and interior areas of PR
by 19/19Z, clrg aft 18/23Z. Any MVFR due to CIGS will be brief as it
was earlier this morning at TIST and would be most likely at TISX
and TKPK bfr 19/15Z. Brief MVFR will also be psbl at TJMZ btwn 19/18-
21Z with mtn obscurations over the Cordillera Central. Winds will
continue to prevail from the east to northeast at 10 to 15 kt--
highest along the coasts with sea breeze influences. Max winds NW-N
25-25 kt btwn FL270-470.


&&

.MARINE...Small craft operators should exercise caution as
combined seas are forecast to be between 4 to 6 feet across local
Atlantic waters, Anegada Passage and the off shore Caribbean
waters. A small NE ground swell will continue to reach our
northern exposed coast through at least mid week. Another northern
swell will reach our northmen coast on Saturday night and peak on
Sunday morning. Easterlies winds throught at least mid week on
the range of between 10 to 20 knots. There is a moderate risk of
rip currents across many of the local northern exposed beaches
today.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 88 75 87 75 / 10 10 50 50
STT 86 76 86 76 / 10 10 50 50
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Re: Caribbean - Central America Weather

#19669 Postby cycloneye » Tue Nov 20, 2018 5:12 am

Area Forecast Discussion
National Weather Service San Juan PR
425 AM AST Tue Nov 20 2018

.SYNOPSIS...A generally stable weather pattern to continue through
the end of the week under ridge pattern. However, patches of low
level moisture will assure passing showers later today through
this evening.

&&

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

Fair weather conditions with significantly limited shower activity
will prevail across the forecast area through mid morning. An
area low level moisture now locate just east of the lesser
antilles will enter the Anegada Passage early this morning and
then over the local islands late this morning. Most of these
showers are fast pace moving and no significant rainfall
accumulations are expected. These showers could generate a few
gusty winds as they pass by. After this Fair weather conditions
will continue with significantly limited shower activity across
the forecast area this evening. This is the result of drier air
moving across the region and the effects of a surface to mid-
level ridge of high pressure located over the north central
Atlantic. The occasional patch of low- level moisture is expected
once again Wednesday afternoon into Thursday. If any convection
occurs, especially in the afternoon, it will be short- lived due
to unfavorable environmental conditions.


.LONG TERM...Friday through Tuesday...
On Friday although it will remain relatively stable, moisture
content across the region will begins to increase. After Saturday
the forecast will depend how close the frontal boundary will be
to our local forecast area. On the latest GFS model suggest the
highest amount of moisture will stay over the Atlantic ocean but
enough moisture will reach the local area to increase the chances
of showers from Sunday through Tuesday.

&&

.AVIATION...VFR conditions are expected to prevail across the
forecast area through 21/06Z. As a band of moisture moves westward
across the region, expect VCSH first at TKPK/TNCM around 20/08Z,
then TJSJ at around 20/16Z, TJPS at around 20/22Z, and TJBQ at
around 20/22Z. Afternoon convection will also bring VCSH to
TJMZ/TJBQ between 20/16Z and 20/22Z. Winds will continue to prevail
from the east to northeast at 10 to 15 kt--highest along the coasts
with sea breeze influences and near showers and thunderstorms.

&&

.MARINE...Small craft operators should exercise caution as
combined seas are forecast to be between 4 to 6 feet across local
Atlantic waters, Anegada Passage and the off shore Caribbean
waters. Easterlies winds throught at least mid week on the range
of between 10 to 20 knots. There is a high risk of rip currents
across many of the local northern exposed beaches today.

A A generally stable weather pattern to continue through
the end of the week under ridge pattern. However, patches of low
level moisture will assure passing showers particularly Tuesday
night into Wednesday morning. northerly swell will reach the local
Atlantic waters on Saturday night and peak on Sunday morning.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 87 76 87 76 / 40 60 20 20
STT 86 77 86 76 / 60 60 10 20
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Re: Caribbean - Central America Weather

#19670 Postby cycloneye » Wed Nov 21, 2018 5:09 am

Area Forecast Discussion
National Weather Service San Juan PR
437 AM AST Wed Nov 21 2018

.SYNOPSIS...A generally stable weather pattern will continue
through the end of the week under ridge pattern. However, patches
of low level moisture will assure passing showers during this
period..


&&

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

Although the current dominant feature is a mid level ridge, a plume
of moisture associated to a short wave perturbation will continue to
result in showers streaming over the local waters and possibly
moving over coastal areas of southern Puerto Rico as it continues to
move westward and away from the local islands. Drier air will invade
once again the forecast area and a more stable weather pattern is
expected through at least Friday morning. That is, mostly clear to
partly cloudy skies with light passing showers streaming over the
waters into windward areas of the islands during the overnight and
early morning hours, followed by the development of showers over
portions of the interior and western Puerto Rico in the afternoon.
Then, the mid level ridge pattern is forecast to weaken on Friday as
a mid level trough pulls from the northwest into the region. This
feature will bring favorable upper level conditions and thus, an
increase in convection across the forecast area after midday on
Friday. Winds will continue from the east around 10-20 knots, but
forecast to decrease on Friday.


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

The old frontal boundary located north of Puerto Rico will slowly
dig south over the local forecast area through Saturday. This
feature will help increase the moisture content over the region
and therefore increase the chance of passing showers across the
local islands. On Monday the Boundary is expected to move North
and drag the moisture with it. High pressure will once again
build over the area after Wednesday generating a more stable and
dry conditions across the local forecast area.


&&

.AVIATION...VFR conditions are expected to prevail across
all TAF sites during the next 24 hours. VCSH possible through at
least 21/13z across all terminals, except for TJMZ. Afternoon
convection will result in VCSH at TJMZ/TJBQ between 21/14z and
21/23z. Winds will continue from the E-ESE at 10-20 kt blo FL100.


&&

.MARINE...Small craft advisory continues in effect for the
offshore Atlantic waters due to seas up to 7 feet. Elsewhere,
small crafts should exercise caution due to seas up to 6 feet
and/or winds up to 20 knots through at least Wednesday. A high rip
current risk remains in effect for the northern beaches of Puerto
Rico. Moderate risk continues across the rest of the island and
across the USVI.

A series of northerly swell are forecast to affect the regional
Atlantic waters. The first pulse of the northerly swell will
reach our local waters on Saturday night and peaking on Sunday
morning. A second pulse will reach the local waters on Tuesday
morning and the third pulse will be on Wednesday afternoon.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 88 76 88 75 / 10 10 20 40
STT 87 75 87 75 / 10 10 40 40
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Re: Caribbean - Central America Weather

#19671 Postby cycloneye » Thu Nov 22, 2018 5:29 am

Area Forecast Discussion
National Weather Service San Juan PR
414 AM AST Thu Nov 22 2018

.SYNOPSIS...A generally stable weather pattern will continue
through Saturday as drier than normal airmass dominates the local
area. An increase in low-level moisture is expected late Saturday
night into early next week as a surface low quickly moves
northeastward into the north central Atlantic, pulling tropical
moisture over the local area. However, shower activity will be
limited as a mid level ridge moves in from the west and affects
the local weather conditions through the rest of the forecast
period.


&&

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

Mostly fair weather pattern is expected to continue for the next few
days as drier than normal airmass dominates the local area. The
available moisture is for the most part limited to the lower levels
with dry air in the mid levels. There is also a mid and upper level
ridge, which is keeping a stable atmosphere. A broad upper trough
will move north of the local area on Saturday and moisture is also
expected to start increasing late Saturday. This means that the
nighttime and early morning trade wind showers will be isolated and
brief, generally leaving trace amounts of rain to a few hundredths
of an inch of rain in the few areas that do observe rain. Then in
the afternoon, especially this afternoon, some light to moderate
showers could develop across the northwestern quadrant of Puerto
Rico due to local effects, but the amounts are not expected to cause
hazardous conditions. A brief patch of moisture may pass through the
area on Friday afternoon, which will help in the development of
showers over Puerto Rico, especially in areas of sea breeze
convergence, while the rest of the local islands may observe little
to no rainfall. Saturday looks mostly dry during the daytime hours,
but moisture will start to increase on Saturday night and will
linger for a few days after that, for more details see below the
long term section.


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

Global models suggest that a surface low pressure will build and
locate north of the region, pulling patches of tropical moisture
into the forecast area Sunday through Monday as it moves quickly
to the northeast. Then, a surface high pressure is expected to
build over the Bahamas late Monday and drift eastward across the
western Atlantic and north of the region through mid week. As a
result, easterly low-level winds will turn from the northeast late
Monday into Tuesday, but will veer to the east southeast on
Wednesday. The low-level moisture that is expected to move across
the local islands during the forecast period will enhance the
potential for shower development. However, a mid level ridge
drifting eastward across the region will limit the coverage and
intensity of this activity.


&&

.AVIATION...VFR conditions are expected across the local terminals
for the next 24 hours. Afternoon convection may result in VCSH at
TJMZ/TJBQ between 22/18z and 22/22Z. Winds will be from the E to ESE
with sea breeze variations at 10-15 KT.


&&

.MARINE...Choppy/Rough marine conditions are expected to continue across
the outer Atlantic and Caribbean waters, as well as the Mona and
Anegada Passage due to seas up to 6 feet. Therefore, small craft
operators should exercise caution. Elsewhere, seas up to 5 feet
are expected. Easterly winds up to 20 knots will continue across
the regional waters. A high rip current risk remains in effect
until early this morning for the north central coast of Puerto
Rico. Then, a low to moderate risk will continue at least through
Sunday for beaches of Puerto Rico and the U.S. Virgin Islands.

A series of northerly swell are forecast to affect the regional
Atlantic waters and local passages. The first pulse of the
northerly swell will reach our local waters late Saturday night, peaking
on Sunday morning and continuing through Monday morning. A second
pulse will reach the local waters on Wednesday afternoon, peaking
late Wednesday night and continuing until Friday.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 87 74 85 73 / 20 30 30 30
STT 86 76 84 74 / 30 30 20 20
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Re: Caribbean - Central America Weather

#19672 Postby cycloneye » Fri Nov 23, 2018 5:30 am

Area Forecast Discussion
National Weather Service San Juan PR
501 AM AST Fri Nov 23 2018

.SYNOPSIS...The combination of a patch of low-level moisture
moving across the area and an approaching upper level through
will aid in the development of showers and possible thunderstorms
across the local islands today. Conditions will somewhat dry out
on Saturday, but a low pressure system moving over the western and
into the north central Atlantic is expected to enhance moisture
transport over the region by Sunday and Monday. Although the
chance of shower development may increase during this period,
upper level conditions are not expected to favor any significant
development. A more stable weather pattern will return by Tuesday
through the end of the workweek.


&&

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

A patch of moisture is moving in and causing light rain across the
USVI into eastern PR, this shower activity is expected to dissipate
by the mid morning hours. An upper trough will be over Hispaniola by
the afternoon hours, causing some divergence aloft over the local
area, which may combine with the available moisture and local
effects to cause showers to develop in the afternoon across the
northwestern quadrant of PR. Given this pattern, there is a slight
chance of a brief thunderstorm this afternoon, but the mid levels
are rather dry and forecast soundings show an inversion at about
650mb, which might be a bit much to overcome to cause a
thunderstorm. However, the WRF model is suggesting small areas with
good rainfall in the mid afternoon hours, and given the fact that
there is currently more moisture and rainfall than what the models
are suggesting, a brief thunderstorm this afternoon seems unlikely
but a slight possibility will not be ruled out.

Saturday looks fairly dry again with the exception of some moisture
across the Caribbean waters and slightly increasing moisture over the
local area on Saturday afternoon. This moisture may combine with the
local effects and diurnal heating to cause the development of
showers across the northwestern quadrant of PR once again in the
afternoon, while the rest of the local islands observe fair weather.
Similar pattern is expected on Sunday as we have slightly higher
moisture and showers over western PR in the afternoon could develop
due to local effects.


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

Global models continue to suggest that the trailing edge of a complex,
non-tropical low pressure system will enhance moisture transport
into the forecast area on Monday as it moves quickly eastward to
east-northeastward over the western and north central Atlantic.
During the same period, a surface high pressure is forecast to
build over the Bahamas and drift eastward across the western
Atlantic and north of the region through the middle of the week.
As a result, easterly low-level winds will turn from the northeast
on Monday through Wednesday, but will veer to the east southeast
on Thursday. Any patch of low-level moisture that will move across
the local islands will enhance the potential for shower
development. However, a mid level ridge drifting east-
northeastward into the northeastern Caribbean and central Atlantic
will suppress the coverage and intensity of this activity.


&&

.AVIATION...VFR conditions are expected across the local terminals
for the next 24 hours. Afternoon convection may result in VCSH at
TJMZ/TJBQ between 23/18z and 23/22Z. Winds will be from the E to ESE
with sea breeze variations at 10-15 KT.


&&

.MARINE...Seas are expected to remain at or below 5 feet at least
until Sunday, when seas will increase slightly with the arrival of
a northerly swell. However, only precautionary states may be
require at the time, particularly for the Atlantic waters and
local passages. A moderate risk of rip currents will continue for
most beaches along the north coast of Puerto Rico, and a few
beaches of Culebra, Vieques and the U.S. Virgin Islands. The risk
of rip currents may increase to high Saturday afternoon.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 86 76 87 75 / 30 20 20 20
STT 85 75 85 75 / 20 10 20 20
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Re: Caribbean - Central America Weather

#19673 Postby cycloneye » Sat Nov 24, 2018 5:35 am

Area Forecast Discussion
National Weather Service San Juan PR
413 AM AST Sat Nov 24 2018

.SYNOPSIS...The mid to upper level ridge will generate dry and
stable conditions across the region, This feature will limit the
shower development until at least Sunday. Moisture associated to a
frontal boundary now located north of the region will move closer
increasing the chances of rain on Sunday and Monday. On Tuesday
the ridge is forecast to build over the local area returning to a
more dry and stable pattern.

&&

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

Relatively dry airmass expected to continue today across the local
area, especially over Puerto Rico. There is an area of higher
moisture over the USVI and the Caribbean waters, which is expected
to develop into a line of moisture and continue through Monday as
moisture gets pulled by a surface low pressure system over the west
central Atlantic. Even though there is some higher moisture nearby,
the shower activity should be limited and mostly limited to the local
waters, USVI, and eastern PR in the morning hours. The mid levels
are too dry to support any significant shower development in the
afternoon over Puerto Rico. The forecast soundings are suggesting
precipitable water values mainly between 1.0 and 1.3 inches for
today, which is rather dry, with most of the dry air above 700mb,
but the lower levels do not look particularly moist either. Having
said that, the lower levels moisten up a bit on Sunday, which could
bring scattered showers to the USVI and eastern PR in the early
morning hours, then some showers could develop over PR in the
afternoon hours. Then for Monday, as the line of moisture develops
and brings deeper moisture, the latest guidance insists that the
eastern third of PR and perhaps the islands of Vieques and Culebra
could observe scattered showers in the morning hours with the
southwestern quadrant of PR possibly observing more significant and
persistent rainfall in the afternoon, according to the WRF model.

.LONG TERM...Tuesday through Saturday

Frontal Boundary will remain stationary North of the local region
through this forecast period with a mid to upper level ridge
dominating the local forecast area. Although pulses of moisture
are expected to move across the region, rainfall accumulations
will not be significant. As the week goes by the frontal boundary
will move closer to our region increasing the chances of showers
for Saturday and Sunday

&&

.AVIATION...VFR conditions are expected across the local terminals
for the next 24 hours. There may be some -SHRA across western PR
after 24/18Z but these showers if they affect any of the local
terminals it would be mainly in the vicinity and should be
relatively short lived. Winds will be at around 10 kts from the SE
for TIST, TISX and TJPS terminals, then E to NE for TJSJ and TJBQ,
with TJMZ observing westerly winds due to sea breeze variations.


&&

.MARINE...Tranquil marine conditions will prevail through at least
Tonight with seas between 2 to 4 feet and winds at around 10
knots. Tonight a northerly swell is forecast to affect the
Atlantic waters an all local passages. Swells are expected to
peak at 6 feet early Sunday morning and subside on Monday.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 89 76 88 76 / 10 20 10 40
STT 86 76 86 75 / 10 20 30 30
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Re: Caribbean - Central America Weather

#19674 Postby cycloneye » Sun Nov 25, 2018 5:32 am

Area Forecast Discussion
National Weather Service San Juan PR
410 AM AST Sun Nov 25 2018

.SYNOPSIS...The main feature dictating our weather pattern for the
next several days is a mid to upper level ridge will continue to
build and reestablish across the region through Friday and
therefore maintain overall dry and stable conditions.


&&

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

Fair weather is expected for most of the local area in the morning
hours with showers developing in the afternoon, initially across the
interior sections of Puerto Rico and then possibly displacing west
and north of central PR. Some of the local guidance suggests that
some of the showers could be significant enough to cause ponding of
water on poor drainage areas. All this is because a narrow band of
moisture is expected to move over PR in the afternoon hours, which
will combine with the diurnal heating and local effects to have
these showers develop. The local winds are rather light, so the
showers are expected to develop in the interior pf PR, then due to
its own outflow, more showers could develop later in the afternoon
away from the interior of PR. The forecast soundings suggest that
even though moisture is to increase slightly this afternoon, the mid
levels are still rather dry and the upper levels are not conducive
to thunderstorm development, therefore scattered to locally numerous
showers are forecast but thunderstorms were left out. The coastal
sections of Puerto Rico as well as the USVI should observe mainly
fair weather with only a slight chance of showers. Having said that,
keep in mind that some of the showers over PR could displace
outwards from the interior of PR, particularly to western PR and
some sections of the north central, eastern interior and near the San
Juan metro, causing brief showers in the afternoon. There is some
uncertainty though since too many factors come into play.

The local winds will still be on the lighter side, around 10 mph and
lower across the interior sections of PR, becoming a bit more east
northeasterly while the available moisture will be mainly limited to
the lower levels on Monday and Tuesday. This setup will continue to
promote mainly fair weather across the local islands, isolated or
brief showers, if any, across the USVI and eastern PR during the
nighttime hours and some showers to develop across western PR in the
afternoon. A slightly higher patch of moisture could move in on
Monday night into Tuesday, causing scattered showers across the
north and eastern sections of PR and the northern USVI. With regards
to temperatures, seasonable temperatures are expected, highs in the
mid to upper 80s across the lower elevations of PR and across the
USVI.

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

The mid to upper level ridge will generate dry and stable conditions
across the region, This feature will limit the shower development
until at least Friday. Only expect patches of moisture generating
passing shower across the local region and some showers across the
interior and western of Puerto Rico each afternoon. The GFS model
suggest that for the incoming weekend these patches of moisture
will become larger and more frequent therefore increasing slightly the
chance of showers for this period.


&&

.AVIATION...VFR conditions are expected across the local terminals
for the next 24 hours. There may be some SHRA across central into
western PR after 25/18Z, which could at times reach the vicinity of
the terminals in PR. Winds will be generally light, heavily
influenced by sea breeze variations at around 5 to 10 knots.


&&

.MARINE...Local buoys already are already reporting the arrival
of the northerly swell across the local Atlantic waters and local
passages. The Buoy 41043 at 7:50 pm on Sunday showed the peak of
the episode and now is showing a slow decrease on the height of
the swell. Near shore Caribbean waters should expect seas of
between 1 to 3 feet. Winds will remain at around 10 kts.

Beachgoers should be aware moderate to occasional large breaking
swells along the northern coast of Puerto Rico and USVI. For this
reason there is a high rip current risk for the Northwest through
northeast facing beaches of Puerto Rico and Northern USVI.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 87 76 86 75 / 20 20 20 30
STT 85 76 86 75 / 20 20 20 30
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Re: Caribbean - Central America Weather

#19675 Postby cycloneye » Mon Nov 26, 2018 5:22 am

Area Forecast Discussion
National Weather Service San Juan PR
503 AM AST Mon Nov 26 2018

.SYNOPSIS...Surface high pressures at the surface, mid levels, and
upper levels will continue to promote mainly fair weather across
the local islands for the next couple of days, with the exception
of some areas of western Puerto Rico due to local effects and the
limited available moisture. Light to moderate winds are expected
for the next several days. Seasonable temperatures are also
expected. No major feature is expected to have significant impacts
over the local islands.

&&

.SHORT TERM...Today through Wednesday...
Showers developed across the coastal waters of southwest Puerto Rico
and the northern U.S. Virgin Islands overnight. However, showers
stayed along the coastal waters and no activity was detected over
land, where skies remained mostly clear. Tranquil weather conditions
will persist through the morning hours. But, diurnal and local
effects will aid in the development of showers across the interior
and northwest sections of Puerto Rico as well as downwind from El
Yunque and from the Virgin Isles.

A mid-upper level ridge will continue to build and remain the main
feature over the islands. Under this pattern and with an easterly
wind flow, dry and stable atmospheric conditions will prevail
through the sort-term. Although, moisture will remain below November
normal values, a patch of moisture is forecast to reach the islands
by Tuesday morning. This band will increase shower activity, but the
mid-upper level ridge should suppress its vertical development. At
this time, Wednesday would be another beautiful day with little or
no shower activity, mostly sunny skies and seasonal temperatures.

.LONG TERM...Thursday through Tuesday...

Rather uneventful weather pattern is in store in the long term.
Latest guidance is suggesting that a surface high pressure will
move into the western Atlantic and move east, north of the local
islands and remain dominating the local wind flow through the long
term period, while there is a frontal boundary to the north of the
local islands but that will remain just north of 20N before it
weakens and fragments, having no impact locally. Then in the
upper levels it looks like we will be under the influence of a
ridge and same could be said for the mid levels. The available
moisture in the long term will vary in patches of below normal to
normal and briefly above normal moisture. So we will be observing
fair weather but the chances of rain will increase when one of
these patches of moistures passes over the local area. Having said
that, even when moisture increases in one of these patches, the
moisture will be mainly in the lower levels, it is not until very
late in the forecast period that the column of moisture is
observed through the mid levels, but this is very late in the
period and confidence is really low. So at this time we can expect
fair weather with moments of scattered showers when a patch of
moisture moves in.

&&

.AVIATION...VFR conds are expected through the morning and early
afternoon hours across the local terminals. SHRA expected across
western PR after 26/18Z could cause VCSH at TJMZ, TJBQ and TJPS.
Light winds through 26/13Z, increasing to 10-15KT from the east
with sea breeze variations thereafter. Due to the expected
convection in the afternoon, mountain obscurations can be
expected.

&&

.MARINE...Seas are now generally between 2 and 5 feet and the
winds 10 to 15 knots. These fairly benign seas are expected until
late this workweek when a northerly swell, due to a surface low
pressure across the northwestern Atlantic, invades the local
waters.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 87 76 85 74 / 20 10 20 20
STT 87 77 85 74 / 20 20 20 20
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Re: Caribbean - Central America Weather

#19676 Postby cycloneye » Tue Nov 27, 2018 5:05 am

Area Forecast Discussion...CORRECTED
National Weather Service San Juan PR
419 AM AST Tue Nov 27 2018

.SYNOPSIS...Surface high pressure at the surface is weakening and
a surface trough north of the local islands is expected by
Thursday. The mid and upper levels will have a ridge for the next
few days and will continue to promote mainly fair weather across
the local islands for the next couple of days. However, some
areas of western Puerto Rico may observe rain in the afternoons due
to local effects combining with the limited available moisture.
Light to moderate winds are expected for the next several days.
Seasonable and near normal temperatures are expected this week.


&&

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

Surface moisture associated with a pre-frontal band will move from
the southeast and northeast across the U.S. Virgin Islands, east
Puerto Rico and surrounding waters through the morning hours. As
this moisture move inland, it is expected to increase the chance for
shower activity across the Virgin Isles during the morning and
across the interior and west sections of Puerto Rico during the
afternoon hours. A ridge aloft will limit vertical development
across the islands, for that reason no thunderstorms were included
in the forecast package. But, under a weak steering wind flow,
rainfall activity could produce ponding of water on roads and low
lying areas. In addition, urban and small stream flooding should
not be ruled out during the afternoon.

After the passage of this surface feature, the local weather will be
dominated by a mid-high pressure ridge and very dry air Wednesday
and Thursday. As a result, no significant rainfall event is expected
and thunderstorms were not included in the forecast package.
However, isolated to scattered showers should not ruled out each
afternoon over the interior and western Puerto Rico.

.LONG TERM...Friday Through Wednesday...

Very little to no change in the long term forecast compared to
what we discussed yesterday. It still looks like a pretty
uneventful weather pattern is to be expected with perhaps the
only important feature being an upper low over the local area at
the very end of the forecast period on Wednesday, which is frankly
too far to put too much weight on it at the moment. Having said
that, the latest guidance is still suggesting that a surface high
pressure will move into the western Atlantic on Friday and move
east, to the north of the local islands and remain dominating the
local wind flow through the first half of next week. There may be
a frontal boundary to the north of the local islands on Friday,
but will remain north of 20N before it dips a bit further south
while it weakens and fragments on Saturday, having no impact
locally other than an increase in moisture across the local area
on Sunday night. In the upper levels it still looks like we will
be under the influence of a ridge until at least Tuesday, with the
aforementioned upper low possibly developing on Wednesday. We
will have a ridge in the mid levels through the long term period.
The available moisture in the long term will vary in patches
except maybe on Monday where the fragmented frontal boundary may
provide persistent moisture over the local area. So we will be
observing fair weather but the chances of rain will increase
slightly when moisture increases over the local area, but there is
really no significant increase in the rainfall forecasts from the
long range model solutions. So at this time we can still expect
mainly fair weather with moments of scattered showers when a patch
of moisture moves in.

&&

.AVIATION...VFR conds are expected across the local terminals.
However, mountain obscuration should not ruled be out across the
interior and western PR this afternoon. As a result, SHRA/-SHRA
could impact TJBQ/TJMZ between 27/16-22z. Surface winds will
continue calm to light-vrb through 27/13Z, increasing to 10-15KT
from the east with sea breeze variations thereafter.

&&

.MARINE...Seas are generally between 2 and 5 feet and the winds
10 to 15 knots. These fairly benign seas are expected until late
in the workweek when a northerly swell invades the local waters,
causing seas to increase to at least 6 feet on Friday.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 87 75 88 73 / 30 20 10 10
STT 86 76 84 73 / 30 20 10 10
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Re: Caribbean - Central America Weather

#19677 Postby cycloneye » Wed Nov 28, 2018 4:57 am

Area Forecast Discussion
National Weather Service San Juan PR
504 AM AST Wed Nov 28 2018

.SYNOPSIS...
Below normal dry conditions will prevail across the islands
through the end of the work-week. Aloft, a mid-upper level ridge
will inhibit vertical development and thus thunderstorm formation.
However, overnight and early morning showers across the windward
sections of Puerto Rico and the U.S. Virgin Islands followed by
afternoon showers across the interior and west Puerto Rico should
not be ruled out each day.

&&

Short Term...Today through Friday...

A mid to upper level ridge over the central and eastern Caribbean
will dominate the local weather conditions through the short term
period. This will continue to promote a drying trend through at
least late Thursday. An upper level trough and associated surface
front are expected to approach the northeast Caribbean between
Thursday and Friday, however, these two features are expected to
provide little support for shower development as the upper ridge
continues to hold over the region and the front lingers near 20N.
Steering winds will continue at less than 10 kt through Thursday.

Diurnally induced afternoon showers are expected to develop today,
mainly over portions of the interior and west/southwest PR. Lacking
any upper level support only light to moderate rainfall amounts are
possible. Maximum temperatures today are forecast to reach the high
80s to low 90s across coastal areas of southern and northern PR and
in the mid to high 80s across the USVI. Models are indicating an
even drier day on Thursday and an increase in low level moisture
across the Caribbean waters on Friday. East to northeast trade winds
will increase once again on Friday as a surface high pressure moves
over the western Atlantic.

.LONG TERM...Saturday through Thursday...
The aformentioned surface high pressure will drift from the
western Atlantic into the eastern Atlantic ocean through the rest
of the forecast period. Under this weather pattern, patches of low
level moisture will reach the islands each day creating a seasonal
weather pattern. Unfavorable upper level dynamic will continue, as
the ridge aloft continues through much of the upcoming week.
However, the latest model guidance suggested the remnants of a
frontal boundary which may provide enough surface moisture to
increase shower activity Sunday-Tuesday. In general, fair weather
conditions will persist through much of the forecast period.

&&

.AVIATION...
Mainly VFR conditions are expected to prevail during the
next 24 hours across all terminals. Showers expected mainly across
the regional waters and between 16z-22z over the interior and
southwestern sections of PR. Light ESE winds will continue with sea
breeze variations aft 15z.

&&

.MARINE...
Tranquil marine conditions with seas below 5 feet and winds
between 5 and 15 knots will continue across the local waters
through at least Friday. Then a northerly swell is expected to
reach the regional waters, increasing seas between 5 and 7 feet.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 88 74 87 75 / 10 0 10 20
STT 85 72 85 74 / 20 0 20 20
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Re: Caribbean - Central America Weather

#19678 Postby cycloneye » Wed Nov 28, 2018 4:38 pm

Record high temperature for the 28th of November was tied in San Juan,Puerto Rico.

 https://twitter.com/NWSSanJuan/status/1067893309958426624


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Re: Caribbean - Central America Weather

#19679 Postby cycloneye » Thu Nov 29, 2018 5:22 am

Area Forecast Discussion
National Weather Service San Juan PR
501 AM AST Thu Nov 29 2018

.SYNOPSIS...
Below normal dry conditions will prevail through at least
Saturday. At upper level, a mid-upper level ridge will inhibit
vertical development and thus thunderstorm formation. However,
the trade winds will push patches of surface moisture at times
each day.

&&

.SHORT TERM...Today through Saturday...
Ridge aloft will continue to promote fair weather conditions and
mostly sunny skies are expected across Puerto Rico today. An area
of low level clouds with light showers was moving from the Leeward
Islands into the local Caribbean waters. Therefore a few showers
could move at times across portions of St. Croix today, however,
no significant rainfall amounts are expected. Maximum temperatures
will range between the high 80s to the low 90s across the lower
elevations. Light winds will continue today and are expected to
turn more from the northeast tonight and increase to around 15 kt
through the weekend.

A surface front is forecast to stall just north of the region
through the short term period. A weak shearline will increase the
chances of showers on Friday afternoon, however, lacking any upper
level support only light to moderate rainfall amounts are possible
over portions of the southwestern quadrant of Puerto Rico. Across
the USVI, passing showers should increase with the best rainfall
accumulations expected over St. Croix.

.LONG TERM...Sunday through Friday...
A backdoor front is expected to dig into the region increasing
shower activity by early next week. However, model guidance still
suggesting unfavorable upper level dynamic for the development of
thunderstorm activity, as the ridge aloft is forecast to remain in
place through at least Tuesday. Therefore, the best chance for
showers is between late Sunday night into Tuesday.

A retrogressive TUTT is forecast to amplify near the Lesser
Antilles, weakening the ridge pattern aloft, but we will have a
high pressure ridge at mid levels through the long period. Having
said that, a fair weather pattern is forecast for the upcoming
week.

&&

.AVIATION...
Mainly VFR conditions are expected to prevail during the
next 24 hours across all terminals. Light sfc ESE winds will
continue with sea breeze variations after 15z. Winds turn more ENE
after 22z.

&&

.MARINE...
Tranquil marine conditions with seas below 5 feet and winds
between 5 and 15 knots will continue across the local waters
through late tonight. Then a northerly swell is expected to reach
the regional waters, increasing seas between 5 and 7 feet across
the Atlantic Waters.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 88 74 86 76 / 0 0 0 10
STT 85 74 85 76 / 10 10 20 20
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Re: Caribbean - Central America Weather

#19680 Postby cycloneye » Fri Nov 30, 2018 4:49 am

Area Forecast Discussion
National Weather Service San Juan PR
503 AM AST Fri Nov 30 2018

.SYNOPSIS...
A surge of moisture will bring passing showers across the
windward sections of the islands through the morning hours.
Thunderstorm development is not anticipated due to a mid to upper
level ridge pattern. Another dry air mass is expected to reach the
islands by late Saturday morning into early Sunday.

&&

Short Term...Today through Sunday...

A mid to upper level ridge will continue to hold through the short
term period. Promoting fair weather conditions in general across the
region. At lower levels, a surface front is forecast to stall north
of the region while a surface high pressure builds behind the front
promoting an east to northeast wind flow across the region. This
will bring patches of low level clouds and light to moderate passing
showers through the weekend. Although models suggest an increase in
precipitable water content, it will continue below normal values.
At least through Sunday, diurnally induced afternoon showers should
develop each day over portions of the interior and west/southwest PR
and as steering winds increase between 15-20 kt, streamers should
develop off the USVI around noon each day.

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

The remnants of a frontal boundary is expected to dig into the
region increasing the available moisture as well as shower
activity by early next week. Thunderstorm development is not
anticipated at this time, as the ridge aloft is forecast to
remain in place through much of the forecast period. However,
model guidance suggested a good chance for moisture advection
between Monday and Tuesday.

A retrogressive TUTT is forecast to amplify near the Lesser
Antilles by mid-week, but should remain far enough to impact the
local region. Having said that, a fair weather pattern is forecast
to continue, with the arrival of patches of moisture at times.

&&

.AVIATION...
Mainly VFR conditions are expected to prevail during the
next 24 hours across all terminals. However, SHRA is expected over
western PR between 16z-22z impacting mainly TJMZ. ENE winds at the
sfc btw 10-15 kt, sea breeze variations expected aft 15z across
southwestern PR.

&&

.MARINE...
A north-northwest swells was detected moving across the local
waters. Mariners can expect seas between 5 and 7 feet with
occasional seas up to 9 feet across the Atlantic Waters. As a
result, a small craft advisory is in effect for the Atlantic
Offshore waters. Winds will gradually increase across the
regional waters and local passages through the upcoming weekend.
Small craft operators are urge to exercise caution over the expose
local waters. Marine conditions are forecast to improve by mid-
week of the upcoming week.

Beach goers should exercise caution from the northwest through
northeast coastline of Puerto Rico, Culebra and St Thomas due to a
high risk of rip currents.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 85 76 87 74 / 20 20 10 20
STT 86 75 86 75 / 20 50 50 10
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