Caribbean - Central America Weather

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cycloneye
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Re: Caribbean - Central America Weather

#19541 Postby cycloneye » Wed Aug 22, 2018 5:11 am

Area Forecast Discussion
National Weather Service San Juan PR
518 AM AST Wed Aug 22 2018

.SYNOPSIS...Weak tropical wave now located over the east Caribbean
basin will continue to move west and across the local forecast
area later today through Thursday morning. This will increase the
cloud, shower and thunderstorms coverage. Another tropical wave
is forecast to enter the eastern Caribbean by next Wednesday.


&&

.SHORT TERM...Today through Thursday...
Surface high pressure will remain anchored across the north central
Atlantic to maintain a moderate east to southeast wind flow.
Gradually eroding mid to upper high pressure ridge extending across
the northeastern Caribbean will shift westward while a Tutt slowly
retrogrades over the region during the next few days. This feature
will therefore continue to enhance tradewind showers as they make
their way across the coastal waters and reach parts of the islands
mainly during the late evenings an the earl morning hours. Local and
diurnal effects along with this weakening upper level ridge, will
give way to locally enhanced showers and thunderstorms mainly across
portions of the interior and northwestern PR this afternoon.

Some of the afternoon convection will cause urban and small stream
flooding particularly over parts of western PR as well as ponding of
water on roadways and in poor drainage areas around the San Juan
metro area. Several areas across Puerto Rico remain fairly saturated
and as a result river and small streams will quickly react and may
lead to rapid rises in water levels. Mudslides will remain possible
in areas of steep terrain across the interior and west section of
Puerto Rico. Lesser showers activity is expected around Culebra,
Vieques and the U.S. Virgin Islands today as a dry slot will move
across the area.

A weak tropical wave is forecast to move across the region on
Wednesday, therefore expected another round of early morning g and
afternoon convection with areas of enhanced showers and thunderstorms
possible particularly over the interior, north and west sections of
Puerto Rico. There is still good potential for river and urban and
small stream flooding with the development of strong thunderstorms
in isolated areas, as well as mudslides in areas of steep terrain.
A gradual improvement in the weather conditions is expected by
Thursday afternoon as the upper trough fills and moisture transport
decrease across the region. Locally induced afternoon showers and
isolated thunderstorms cannot be ruled out but the activity should be
of short duration and less intense.

.LONG TERM...Saturday through Tuesday...
During this period we should continue to receive the moisture
influx mainly through the incoming weekend. Therefore expect
showers and thunderstorms to develop each afternoon, mainly over
the interior and western portions of Puerto Rico. Model guidance
have push back the arrival of a better organized tropical wave,
now expected for Wednesday with the bulk of moisture moving across
the local forecast area between Wednesday night and Thursday
morning.

&&

.AVIATION...VFR. Mostly SCT cld lyrs nr FL025...FL050...FL080 with
passing SHRA ovr regional waters and between PR and the Northern
Leeward Islands. Fm 21/17z-21/22z...SHRA/Isold TSRA ovr W-NW PR and
vcty TJMZ/TJBQ and WNW of El Yunque vcty TJSJ. Brief Mtn Tops obsc
psbl ovr E PR til 21/12z...and ovr W interior PR durg aftn due to
SHRA/TSRA. Wnds E-ESE 5-10kts bcmg 15-20 kt aft 21/14z.


&&

.MARINE...Mariners should exercise cautions as winds will between
15 to 20 knots across the local waters generating waves between 3
to to 5 feet in choppy seas. A weak tropical wave will move
across the regional waters today through Thursday morning.
Mariners should expect and increase on showers and thunderstorms.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 87 78 88 78 / 40 40 30 30
STT 90 80 89 78 / 50 20 20 20
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Re: Caribbean - Central America Weather

#19542 Postby cycloneye » Thu Aug 23, 2018 5:57 am

Area Forecast Discussion
National Weather Service San Juan PR
445 AM AST Thu Aug 23 2018

.SYNOPSIS...The summer pattern of night and morning showers over
eastern Puerto Rico and showers and thunderstorms in western
Puerto Rico in the afternoon will continue as easterly trade
winds continue over the area from high pressure in the northeast
central Atlantic. Isolated showers will continue around the U.S.
Virgin Islands. The next significant feature is a tropical wave
expected to pass through the area next week on Wednesday with
numerous showers and scattered thunderstorms Tuesday night
through Thursday.

&&

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

Partly cloudy skies prevailed across the forecast area overnight and
early this morning with passing showers noted over the northern USVI
as well as eastern Puerto Rico. Coastal temperatures were in the
upper 70s to low 80s under east southeast winds at 10 mph or less.

Ridge aloft will continue to erode as an upper level trough
amplifies into the Caribbean basin. The trough aloft will then
become the dominant feature Saturday onwards. At lower levels,
easterly winds will prevail through the forecast period, but briefly
becoming east northeast on Friday as a low level disturbance moves
north of the area.

Although a drier air mass is expected to encompass the forecast area
today, continue to expect locally induced afternoon showers and
thunderstorms across west and northwest Puerto Rico as well as some
streamers forming over the USVI, Vieques and Culebra. Intensity and
areal coverage of afternoon showers and thunderstorms are expected
to increase during the upcoming weekend as the environmental
conditions will become more favorable due to amplifying trough.
Under northeasterly winds, showers and thunderstorms will be focused
across southwest Puerto Rico Friday afternoon. Shower and
thunderstorm activity will return over west and northwest Puerto
Rico Saturday afternoon.

.LONG TERM...Sunday through Thursday...
A weak tropical wave will pass through the area on Sunday to
deliver showers and thunderstorms to much of Puerto Rico and at
least a few showers to the U.S. Virgin Islands. A weak trough
extends southwest form the TUTT low to our northeast and will
contribute to some divergence aloft during the afternoon hours.
Precipitable water will be average to slightly above average, but
this still means a little more than one and three quarters of an
inch. Our typical shower pattern will continue through Tuesday as
areas of moisture parade through in moderate trade wind flow.
Then on Tuesday night surface flow turns more east northeast as a
tropical wave approaches the area with the best moisture since at
least last week. This will cause a considerable increase in shower
and thunderstorm activity Tuesday night through Thursday. The
tropical wave will have deep moisture even if the TUTT low, that
was just northwest of the area on Tuesday retreats to the
northwest and enlarges over the western Atlantic just north of 25
north, leaving less than optimal upper level dynamics to enhance
convection. Nevertheless, at this time the GFS has a lifted index
of minus 10 at 30/18Z. If this should hold, some thunderstorms
could yield small hail and gusty winds along with the usual urban
and small stream flooding in west northwest Puerto Rico.


&&

.AVIATION...VFR conditions are expected to prevail at all TAF sites
with VCSH likely in and around the USVI terminals as well as JSJ.
Aft 23/16z, brief periods of MVFR conds are possible in SHRA/TSRA at
JBQ/JMZ through 23/22z. ESE winds 15 to 20 knots with sea breeze
variations to continue.


&&

.MARINE...Seas are not forecast to exceed 6 feet during the next 7
to 8 days and the highest seas are not expected until the day after
the tropical wave described above passes next Wednesday. Winds of
15 to 20 knots will occur fairly regularly around the north and
south coasts so mariners will need to exercise caution.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 88 78 87 79 / 20 30 30 50
STT 90 80 90 79 / 40 30 30 50
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Re: Caribbean - Central America Weather

#19543 Postby cycloneye » Fri Aug 24, 2018 5:40 am

Area Forecast Discussion
National Weather Service San Juan PR
530 AM AST Fri Aug 24 2018

.SYNOPSIS...An area of moisture will move into the area from the
northeast bringing increased shower and thunderstorm activity.
Weak low-level perturbances will cross the islands today and
Sunday. Then a tropical wave will again increase shower and
thunderstorm activity Tuesday night through Thursday.

&&

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

Variably cloudy skies prevailed across the local islands overnight
and early this morning with passing showers observed across the U.S.
Virgin Islands and the north and east coastal areas of Puerto Rico.
However, rainfall accumulations associated with these showers were
minimal. Coastal temperatures were in the upper 70s to low 80s under
east northeast winds at 10 mph or less.

An upper level trough will continue to slowly amplify into the
forecast area, becoming the dominant weather feature during the
weekend. This feature will enhance moisture transport as well as
convective instability across the forecast area Saturday onwards. At
lower levels, although an east northeast wind flow will prevail
today, easterly winds will return by Saturday.

Under the aformentioned pattern, continue to expect passing showers
across the US Virgin Islands and the north and east coastal areas of
Puerto Rico throughout the day with showers and thunderstorms
developing over southwest Puerto Rico in the afternoon. Urban
flooding is likely with the heaviest showers. As the trough aloft
enhances moisture transport and convective instability, the chance
for showers and thunderstorms will increase across the forecast area
during the weekend. Showers and thunderstorms should remain focused
across western areas of Puerto Rico Saturday afternoon, but by
Sunday afternoon most areas should experience shower and
thunderstorm activity.

.LONG TERM...Monday through Friday...
A weak trough will move through the area on Monday, but available
moisture will be at its lowest value for the week at around 1.5
inches, so shower and thunderstorm activity will be fairly
modest. Some of the thunderstorms will, however, be strong enough
to cause localized urban and small stream flooding in western
Puerto Rico. After Monday evening overall moisture begins to ramp
up, reaching a peak of over 2 inches on Thursday evening. The
tropical wave (currently moving out of Africa now) will roll
through the area Wednesday and Thursday. The GFS is now showing
the wave to be a little less well-defined, but moisture amounts
have remained consistent, so we continue to forecast shower and
thunderstorm activity increasing Wednesday into Thursday with
diminishing activity in the early morning hours both days. This
will mean that urban and small stream flooding will be likely in
many areas during the afternoons and early evenings Wednesday and
Thursday. The GFS had been forecasting very unstable conditions,
however this latest 24/00Z run is showing only minus 7 for the
lifted index (30/18Z) rather than minus 10 and this is consistent
with the model`s weakening characterization of the passing wave.
There is a dry slot after the tropical wave that should move
through Thursday night, but bubbles of moisture move through on
Friday again to maintain favorable conditions for scattered
showers during the morning and showers and thunderstorms in the
west during the afternoon.

&&

.AVIATION...VFR conditions are expected to prevail at all TAF sites
with VCSH likely at TIST/TISX and TJSJ. Aft 24/16z, SHRA/TSRA
expected across sw PR with mtn obscurations, and therefore brief
periods of MVFR conds at TJMZ/TJPS can`t be ruled out through
24/22z. ENE winds at around 15 knots with some sea breeze
variations.

&&

.MARINE...Some of the quietest marine conditions of the summer are
upon us. Although winds will cause seas to rise briefly at times
to 5 feet through Wednesday in exposed areas of the local waters,
relatively tranquil conditions will continue. Then on Wednesday
night and Thursday, the passing tropical wave will cause seas to
rise to almost 7 feet. At this time small craft advisories may be
necessary for the local outer waters.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 87 78 88 77 / 60 40 40 50
STT 89 80 89 78 / 60 40 40 50
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Re: Caribbean - Central America Weather

#19544 Postby cycloneye » Sat Aug 25, 2018 5:08 am

Area Forecast Discussion
National Weather Service San Juan PR
520 AM AST Sat Aug 25 2018

.SYNOPSIS...Areas of moisture continue to wash over Puerto Rico
today through Tuesday. A weak perturbations will complement better
moisture Sunday afternoon. On Wednesday and Thursday a tropical
wave will move through the area and bring in numerous showers and
scattered thunderstorms. This better moisture will continue
through at least Friday night.

&&

.SHORT TERM...Today through Monday...
This morning passing showers were observed over most of the outer
Atlantic waters this resulted in light rainfall accumulations.
Another surge of moisture is moving in from the east. The MIMIC-
TPW product showed this area of moisture reaching the U.S. Virgin
Islands just after 25/06Z. It will then move over Puerto Rico
this afternoon. Therefore, islands east of Puerto Rico will see
scattered showers this morning through the afternoon, while
portions of the interior and western Puerto Rico will see showers
and isolated thunderstorms during the afternoon.

Sunday, a mid to upper level trough will move back from the west
to the north of Puerto Rico thus increasing instability over the
area. This, combined with diurnal heating, and low level moisture
will enhance showers and thunderstorms over Puerto Rico. The
strongest convection is forecast to be over portions of western
Puerto Rico during the afternoon hours.

Monday, the trough moves through the area but due to weak upper and
low level forcing scattered showers and isolated thunderstorms at
this time are only expected across the western areas of Puerto Rico.
However, due to diurnal heating and local effects some storms may
intensify in other areas during the day. The western and interior
portions of Puerto Rico has received moderate to heavy rain each
day last week so the soils remain saturated. Therefore, any
additional rainfall this weekend and early next week could cause
urban and small stream flooding, as well as ponding of water on
roadways and possible mudslides.

.LONG TERM...Tuesday through Saturday...
Moisture continues to be abundant on Tuesday, lower level winds
gain a northerly component late in the day as the tropical wave on
Wednesday approaches. Also robust divergence aloft is currently
forecast in the GFS, so must continue with ample showers and
thunderstorms for western areas in the afternoon. Then, on Tuesday
night, showers will not taper off as much over eastern Puerto
Rico as the moisture associated with the wave moves into the area.
The GFS has been inconsistent with whether better activity should
be expected Wednesday or Thursday. Certainty in rain chances,
though, is higher on Wednesday and some thunderstorms will be seen
island wide and possibly around the U.S. Virgin Islands then as
well, but moisture levels are still excellent on Thursday and
there is considerable instability in both Wednesday and Thursday`s
18Z forecast soundings showing minus 8 lifted indices. Neither day
appears to have upper level dynamic support like Tuesday to add
complications to the forecast. At this time am leaning toward the
best activity being on Wednesday by a narrow margin. On Friday
patches of moisture develop and pass over the area to hold the
abundance of moisture high, and so, what looked like a drier day
earlier this week, is now looking favorable for continued shower
and thunderstorm activity--mainly during the afternoon and early
evening. Moisture levels drop off considerably on Saturday and we
expect less activity then.

In summary, the upcoming week, looks to be wetter than this week
and river flooding and mudslides in steep terrain may be a concern
that will require some preparation.

&&

.AVIATION...VFR conds are occurring across all terminal sites.
Isold to sct -shra are possible across the U.S. Virgin Islands,
St. Croix and Puerto Rico eastern terminals until 25/18Z.
SHRA/VCTS are possible across terminal sites TJBQ and TJMZ by
25/16Z, with conds improving by 25/22z. As a result SHRA/VCTS
brief MVFR conds are possible at TJMZ and TJBQ. Sfc winds are out
of the east at 10 to 15 kts with easterly winds extending from the
sfc to FL015. Winds turn to the north btwn 19-20 kft at 5 to 10
kts.

&&

.MARINE...Typical winds and seas continue through late Tuesday,
with 15 to 20 kt near the north and south coasts of Puerto Rico
each day, though seas remain below 6 feet. Then as a tropical
wave passes through on Wednesday and Thursday, shower and
thunderstorm activity increases and seas in the northeast local
Atlantic waters may reach 7 feet. Small craft advisories,
therefore, may be necessary Wednesday and Thursday. Conditions are
expected to improve afterward.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 88 77 87 78 / 40 40 40 40
STT 88 78 87 79 / 40 50 50 50
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Re: Caribbean - Central America Weather

#19545 Postby cycloneye » Sun Aug 26, 2018 5:27 am

Area Forecast Discussion
National Weather Service San Juan PR
508 AM AST Sun Aug 26 2018

.SYNOPSIS...A band of moisture will pass through the area today to
continue the showery pattern, with thunderstorms in the west.
Showers will diminish a little on Monday, then moisture from an
approaching tropical wave will invade the area Tuesday and
Wednesday. The wave passage is expected on Wednesday, but showers
and thunderstorms will bring significant rains through at least
Friday. Moisture tapers off over the weekend.

&&

.SHORT TERM...Today through Tuesday...
The upper level trough as well as low level moisture has caused
numerous trade winds showers across the local islands, and the
Atlantic and Caribbean waters this morning. This activity is
forecasted to continue throughout the day, as diurnal heating and
the trough proximity to the Puerto Rico will enhance showers and
thunderstorms this afternoon. High resolution models shows an
east-southeast flow over Puerto Rico this afternoon. This wind
flow will put the heaviest convection across portions of
northwestern and western Puerto Rico, but the proximity of the
upper level trough could cause showers and isolated thunderstorms
in other areas too.

Monday, the upper level trough pulls away from the islands, and
precipitable water values are forecasted to decrease until early
Tuesday. Locally induced showers and isolated thunderstorms are
forecast to develop over portions of western and interior of
Puerto Rico during the afternoon. Elsewhere, showers are expected
over the eastern islands and metro during the morning and
afternoon.

Tuesday, a tropical wave current east of the Lesser Antilles will
continue west with moisture reaching the local area late Tuesday.
This will increase showers and isolated thunderstorms across the
area. The bulk of the moisture is forecast late Wednesday or
early Thursday morning. Either way, the middle of the week looks
to be wet across most of the islands.

.LONG TERM...Wednesday through Sunday...
A weak upper level trough extending southwest from a TUTT low to
Hispaniola will contribute to some good upper level dynamics
Wednesday. The tropical wave will pass through Wednesday afternoon
through Thursday and will bring a good supply of moisture with it.
Although moisture is better on Thursday, current indications are
that the upper level dynamics and the heavy mid and upper level
clouds present on Thursday should limit convection more then than
on Wednesday. Moisture continues above 2 inches of columnar waters
through Friday and then begins to taper off Saturday and Sunday.
Even so showers in the normal diurnal pattern for easterly flow
will continue and showers will be likely on the eastern flanks of
the Luquillo range in the nights and early morning and over
western Puerto Rico in the afternoons through Sunday.

With soils saturated already from the rain that has fallen in the
west northwest third of Puerto Rico, the additional heavy rains
on Wednesday and Thursday are likely to bring urban and small
stream flooding to the area and local rivers may approach flood
stage. Mudslides in steep terrain will also be possible.

&&

.AVIATION...VFR conds are occurring across all terminal sites but
SHRA are expected to continue across PR eastern terminals through
26/16Z. SHRA/VCTS are forecast to increase across terminal sites
TJBQ, TJMZ and TJSJ by 26/16Z, then VFR conds could briefly fall
to MVRF as a result of SHRA/VCTS. Sky and weather conds should
improve by 26/22Z. Elsewhere sct SHRA are possible across the
other terminal sites. Sfc winds out of the east at 10 to 15 kts,
then winds back to the e-ne at FL010 to 20kft at 5 to 15 kts.

&&

.MARINE...Seas will remain below 6 feet through Tuesday with local
areas of 6 feet in the northeast Atlantic. Then the passing
tropical wave will generate better winds and higher seas, such
that borderline small craft advisory condition are likely
Wednesday and Thursday.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 88 78 89 78 / 40 40 40 40
STT 88 78 89 79 / 50 50 50 50
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Re: Caribbean - Central America Weather

#19546 Postby cycloneye » Mon Aug 27, 2018 5:01 am

Area Forecast Discussion
National Weather Service San Juan PR
517 AM AST Mon Aug 27 2018

.SYNOPSIS...A weak upper level trough will remain to the northeast of
the region through the reminder of the work week. A tropical wave is
forecast to move into the region late Wednesday and bring a surge of
moisture over the area. This moisture is expected to remain across
the area through Friday, with showers and isolated thunderstorms
over portions of eastern and western Puerto Rico during the
afternoons. The moisture is forecast to retreat away from the air as
drier air filters in from the east, this drier air will remain until
late Sunday, then another wave will move into the region and
increase showers and thunderstorms on Monday.

&&

.SHORT TERM...Today through Wednesday...
Broad surface high pressure will continue across the subtropical
Atlantic driving 10 to 18 knot easterly trade winds through the
area. The TUTT to our northeast will begin to form a new low today
about 780 miles northeast that will drift west through Wednesday.
Moisture is expected to improve considerably through the day then
remain generally similar through Tuesday evening before increasing
again on Wednesday. Moisture generally increases at lower levels
Monday through Wednesday as does instability below 500 mb. Since
surface winds remain more or less easterly through the period
showers and thunderstorms will develop in western Puerto Rico each
day. And night and early morning showers will occur over the eastern
mountains and slopes. Some urban and small stream flooding is
expected each day, but amounts and coverage should progress today
through Wednesday. At this time although widespread flooding is not
expected some rivers could approach flood stage. Also some areas in
Guaynabo and Bayamon could see some very heavy rains during the
afternoons as the sea breeze interacts with a streamer off of El
Yunque. Thunderstorms with frequent lighting are also expected to
increase as the low pressure aloft develops to our north.

&&

.LONG TERM...Thursday through Monday...A weak upper level trough will
remain to the northeast of the region through the reminder of the
work week. A tropical wave is forecast to move into the region
late Wednesday and bring a surge of moisture over the area. This
moisture is expected to remain across the area through Friday,
with showers and isolated thunderstorms over portions of eastern
and western Puerto Rico during the afternoons. The moisture is
forecast to retreat away from the air as drier air filters in from
the east, this drier air will remain until late Sunday, then
another wave will move into the region and increase showers and
thunderstorms on Monday.

&&

.AVIATION...VFR conds will prevail thru 27/16Z altho brief MVFR is
psbl TNCM/TKPK for CIGS and mtn obscurations will be present in the
Luquillo range of PR. Aft 27/16Z SHRA and psbl TSRA will dvlp VCNTY
TJSJ mostly S-W and also SHRA/TSRA in wrn PR where brief MVFR conds
are expected at TJMZ/TJBQ. Conds impvg aft 27/22Z wrn PR. Sfc winds
ESE 10-20 kt with sea breeze variations bcmg 10-15 aft 27/22Z. Max
winds blo FL540 less than 20 kt..strongest BLO FL070.


&&

.MARINE...Seas will be range from 3 to 5 feet with winds ranging
from 10 to 15 kts with higher gusts possible. Small craft operators
are urged to exercise caution due to choppy seas and winds gust up
to 20 kts. Seas will remain unsettled starting during the middle
of the work week as a result of a tropical wave that will move
into the local water late Wednesday or early Thursday.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 89 79 88 79 / 40 40 40 60
STT 89 80 90 79 / 50 50 60 70
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Re: Caribbean - Central America Weather

#19547 Postby cycloneye » Tue Aug 28, 2018 5:12 am

Area Forecast Discussion
National Weather Service San Juan PR
415 AM AST Tue Aug 28 2018

.SYNOPSIS...A TUTT is forecast to hold to the north and northeast
of the region through Friday. The TUTT combined with low level
moisture associated with a tropical wave that is forecast to move
across the region late Wednesday or early Thursday will increase
low level and upper level instability across the local islands. As
a result, an increase in showers and thunderstorms are expected
through the end of the work week across most of the islands. Early
Saturday morning moisture is expected to abate due to drier air
moving in from the east. The drier air will minimize shower and
thunderstorm develop through Sunday, but local and diurnal effects
still could cause some development mainly during the afternoon.
Late Sunday or early Monday another tropical wave is forecast to
pool moisture over the area, thus an increase in showers and
thunderstorms is expected through Tuesday.


&&

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

Relatively unstable conditions and a moist environment will continue
across the forecast area due to the proximity of a TUTT low and
associated trough. The latter will linger north of the local islands
at least until Friday, before it drifts west northwestward. Then, a
tropical wave will move into the local area late Wednesday into
Thursday. Individually, these features will increase moisture
transport into the area, and thus, an increase in overnight and
early morning showers and possible thunderstorms over the waters and
windward areas of the islands, followed by the development of
afternoon showers and thunderstorms over the interior and western
portions of Puerto Rico, as well as stream-like showers and isolated
thunderstorms off El Yunque and the local islands. The most active
weather is expected each afternoon over portions of western Puerto
Rico due to daytime convection and local effects, but particularly
on Thursday afternoon as the winds veer to the southeast and
precipitable water values peak at around 2.0 inches. Urban and
small stream flooding, as well as quick rises in water levels
along rivers is possible.

&&

.LONG TERM...Friday through Tuesday...
The moisture associated with the tropical wave will diminish late
Friday into early Saturday as a direr air mass filters in from
the east. Although a drier air mass will be in place this weekend
showers and thunderstorms will develop over portions of eastern
and western Puerto Rico during the afternoon due to local and
diurnal effects.

Sunday, a tropical wave 2000 miles to the east of Puerto Rico will
reach the area late Sunday or early Monday. This wave is forecast
to bring another surge of moisture, and increase instability
through Tuesday across the region. The increasing instability and
moisture will help aid in the development of showers and
thunderstorms across the local islands.

&&

.AVIATION...VCSH expected to move over TKPK and TNCM until 28/13Z.
SHRA began to move over TJSJ, thus, a TEMPO was included due to
possible visibility and sky condition changes. A patch of moisture
will bring VCSH to TIST, TISX and TJSJ until at least 28/16Z.
Between 28/16-22Z, an increase in cloudiness due to VCTS development
will result in MVFR conditions at TJSJ, TJMZ and TJBQ. However, VFR
conditions expected elsewhere and once again after 28/22Z across all
terminals. Surface winds are from the E to SE at 10 to 20 knots
dropping to 5-10 knots after 28/22Z.

&&

.MARINE... Seas will range from 3 to 5 feet with east to
southeast winds ranging from 10 to 15 kts. Choppy conditions are
expected over the next several days across most of the local and
outer waters until late this weekend. Showers and thunderstorms
will increase on Wednesday through Friday as a result of a
tropical wave that is forecast to move into the area.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 88 79 87 78 / 50 80 80 60
STT 90 79 89 79 / 60 80 70 60

&&
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Re: Caribbean - Central America Weather

#19548 Postby cycloneye » Tue Aug 28, 2018 5:02 pm

AFDSJU

Area Forecast Discussion
National Weather Service San Juan PR
531 PM AST Tue Aug 28 2018

.SYNOPSIS...Instability caused by a lingering TUTT and an induced
low level trough continued to support afternoon convection over islands
and coastal waters. The cloudiness and shower activity over land will
diminish and move offshore by early evening. However, expect increasing
moisture ahead of a tropical wave overnight through Wednesday morning.
This will bring additional showers and isolated thunderstorms to the
coastal waters and mainly the windward side of the islands. Under the
persistent moist and unstable weather pattern, expect showers and
thunderstorm development each day particularly across the interior
and western sections of Puerto Rico,as well as downwind from east
interior into the San Juan Metro area and on the west end of the
U.S. Virgin Islands.

&&

.SHORT TERM...Rest of today through Thursday...
The unstable conditions and a moist environment will continue
across the region due to the proximity of a TUTT low and associated
trough. The latter will linger north of the islands before it
eventually drifts west northwest and weakens. The tropical wave
is so far expected to cross the local area late Wednesday through
Thursday. The interaction of the Tutt low and the tropical wave
will increase instability and moisture transport across the region
through the end of the work week. Therefore, expect a gradual
increase in moisture transport overnight through early Wednesday
resulting in increased showers and possible thunderstorm activity
over the coastal waters and parts of the islands. During the rest
of the day on Wednesday, good available moisture and instability
will lead to quick development of afternoon showers and thunderstorms
across the interior and western portions of Puerto Rico, as well
as the streamer-like showers and isolated thunderstorms off El
Yunque and downwind of the local islands. Active weather is expected
each afternoon especially over portions of west and northwest Puerto
Rico due to the daytime heating and additional local forcing.

Model guidance continued to suggest Thursday afternoon through Friday
as the wettest period with layered precipitable water values exceeding
2.0 inches. Urban and small stream flooding, as well as quick rises
in water levels along rivers will be likely as well as mudslides in
areas of steep terrain.

.LONG TERM...Friday through Tuesday...
Active and enhanced weather condition expected through Friday
afternoon due to the proximity of the Tutt low. However, expect
moisture trailing the tropical wave to gradually diminish late
Friday through Saturday as a slot of drier air is forecast to move
across the region from the east. Although this drier air mass will
be in place over the weekend, showers and thunderstorm development
will remain possible over portions of interior and western Puerto
Rico during the afternoon due to local and diurnal effects. Lesser
activity is forecast across the U.S. Virgin Islands during that
time.

Another tropical wave is forecast to reach the forecast area late
Sunday or early Monday. This wave is forecast to bring increasing
winds and another surge of moisture and instability through Tuesday.
The increasing instability and moisture will support the development
of showers and thunderstorms across the local islands each afternoon
with potential for areas of locally heavy rains especially over parts
of the central and west Puerto Rico.

&&

.AVIATION...Brief periods of MVFR conds will remain possible at
and vcty JBQ and JMZ and possibly JSJ until at least 28/22z. As a
tropical wave continues to move closer, the chance for SHRA/TSRA
continues to increase. During the overnight hours, VCTS/TSRA
likely in and around the Leeward TAF sites, spreading across the
USVI and eastern Puerto Rico Wednesday morning. ESE winds between
10 to 15 knots becoming at 10 knots or less overnight.Thunderstorm
and shower activity will increase over the region Wednesday and
Thursday.

&&

.MARINE... Marine conditions are forecast to deteriorate Wednesday
through the end of the work week, as the combination of a Tutt low
and a tropical wave will enhance showers and thunderstorm activity
across portions of the regional waters. Afternoon thunderstorms
will also remain likely each day across the coastal waters of the
north and west sections of Puerto Rico through Friday.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 78 88 78 88 / 60 70 70 70
STT 80 90 79 87 / 80 80 70 70
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Re: Caribbean - Central America Weather

#19549 Postby cycloneye » Wed Aug 29, 2018 5:24 am

Area Forecast Discussion
National Weather Service San Juan PR
504 AM AST Wed Aug 29 2018

.SYNOPSIS...A TUTT aloft will continue anchored north of the
region until Friday, generating upper level instability across the
local area. An increase in low level moisture and instability with
the arrival of a tropical wave late today into Thursday will
enhance shower and thunderstorm activity across the forecast area.
A high moisture content will continue until the end of the
workweek, thus a similar convective pattern is expected each day
with a peak in convective development on Friday as the wave phases
with the TUTT aloft. A more seasonal pattern will return on
Saturday and Sunday as a somewhat drier air mass encompass the
local area. However, another tropical wave will pool moisture and
create favorable conditions for shower and thunderstorm
development on Monday and Tuesday. A drier air mass with
occasional patches of low level moisture transported by the trade
winds will move into the area on Wednesday.

&&

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

This second part of the workweek looks to be an active one with
numerous showers and persistent thunderstorms across the local
islands, especially Puerto Rico. The most active period appear to be
most of Thursday through the mid afternoon hours of Friday, but
today looks rather active as well.

Moisture and instability will gradually increase today across the
local area ahead of a tropical wave that is expected for tonight
into Thursday. The shower and thunderstorm activity is expected to
increase today as the day progresses, affecting many parts of the
forecast area, but particularly Puerto Rico. An upper trough,
gradually becoming more conducive to thunderstorm support will help
in the persistent thunderstorm development today and through Friday.
We have the necessary ingredients for enough activity to cause at
the very least some urban and small stream flooding across many
parts of Puerto Rico, but river flooding will not be ruled out, and
it is actually quite possible for more significant flooding to occur
on Thursday and Friday since many of the soils may be saturated and
the additional rain will become runoff right away.

The latest high resolution guidance suggests that the deep moisture
moving in with the tropical wave will combine with the upper level
dynamics and the local effects to cause thunderstorms with heavy
rain.

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

Although patches of drier air will infiltrate the local area
during the weekend, a TUTT pattern aloft will hold north of the
local area until Sunday. This will continue to vent convective
development across the local area. Moisture transport and upper
upper level instability will result in overnight and early morning
showers streaming across the local waters into portions of the
Virgin Islands and eastern Puerto Rico, followed by afternoon
convection over the interior and western Puerto Rico. Models agree
that an east to southeast wind flow will favor afternoon
convection over the northwestern quadrant on Saturday, whereas
convection should be focused over the southwestern quadrant on
Sunday as winds become more northeasterly.

Another surge of moisture is expected early next week as a
tropical wave moves across the local area on Monday into Tuesday.
This will result in enhanced shower and thunderstorm activity
across the area. As the tropical wave moves westward and away
from the local islands, a somewhat drier air mass will invade the
local area on Wednesday.

&&

.AVIATION...SHRA expected across the local area will cause at least
VCSH across the local terminals for the next 24 hours. TSRA is
expected to develop after 29/12Z, which will gradually increase VCTS
across the local terminals from TIST/TISX to TJSJ then to TJPS/TJBQ
and TJMZ starting after 29/16Z. Winds will be from the east today at
10 to 15 knots and gusty with sea breeze variations developing after
29/13Z.


&&

.MARINE...Seas will range between 3 and 6 feet with east to
southeast winds ranging from 10 to 20 kts. As a result, choppy
marine conditions are expected during the next several days
across most of the local waters until at least the end of the work
week. A tropical wave will move across the local area late today
into Thursday, shower and thunderstorm activity will increase
over the local waters.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 88 77 86 77 / 70 70 70 40
STT 90 79 88 78 / 80 70 70 50
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Re: Caribbean - Central America Weather

#19550 Postby HurricaneFan » Wed Aug 29, 2018 8:35 pm

Is the Second Tropical Wave for Monday and Tuesday the same one between 30W and 35W in the Tropical Wave with Low pressure in Eastern Atlantic Thread?
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Re: Caribbean - Central America Weather

#19551 Postby cycloneye » Wed Aug 29, 2018 8:36 pm

HurricaneFan wrote:Is the Second Tropical Wave for Monday and Tuesday the same one between 30W and 35W in the Tropical Wave with Low pressure in Eastern Atlantic Thread?


Yes,that is the one.
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Re: Caribbean - Central America Weather

#19552 Postby cycloneye » Thu Aug 30, 2018 5:06 am

Area Forecast Discussion
National Weather Service San Juan PR
515 AM AST Thu Aug 30 2018

.SYNOPSIS...A TUTT aloft and tropical wave moving across the area
will continue to enhance convective development today through
Friday afternoon. Once the TUTT lifts northward, a short wave
ridge will build from the east, leading to a more seasonal weather pattern
of overnight streaming showers and diurnal convection to the
local islands. Then, another tropical wave is forecast to move
across the area on Monday into Tuesday, enhancing once again showers
and thunderstorms development across the local area.


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

Today and Friday are expected to be an active with numerous showers
and several thunderstorms across the local forecast area as a
tropical wave moves in and interacts with an upper level trough. For
today, the local waters and eastern Puerto Rico seem to be the
preferred locations for active weather by the WRF high resolution
model, interior and western Puerto Rico may experience the better
shower and thunderstorm activity on Friday. Out of today and Friday,
Friday may be the more active day, and depending on how much it
rains today, Friday`s rainfall could have a significant impact on
the flood potential as well as risk of mudslides in areas of steep
terrain.

There is considerable discrepancy amongst the high resolution
models, especially between the NMM and ARW vs the WRF model. The NMM
and ARW have very little activity over PR today and the WRF is very
bullish. We decided to go with the WRF because the other 2 models
were not initializing well, and they didn`t show the thunderstorms
that are currently in the local waters.

Saturday looks much drier as the tropical wave moves away from the
area and the upper trough lifts. There is also a decrease in
moisture. Any shower and thunderstorm development on Saturday should
be locally induced in the afternoon across western Puerto Rico.


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

A short wave ridge will continue to build from the east over the
local area during the weekend, resulting in less favorable upper
level dynamics over the forecast area. However, surface easterly
trade winds will continue to transport patches of low level
moisture into the area, promoting overnight and early morning
showers streaming across the local waters into portions of the
Virgin Islands and eastern Puerto Rico, followed by diurnal
convection over portions of the interior and western Puerto Rico
in the afternoon. As surface winds become more northeasterly on
Sunday, convection should be focused over the southwestern
quadrant of the island.

Another surge of moisture is expected early next week as a
tropical wave moves across the local area on Monday into Tuesday.
The increasing instability and moisture will help aid in the
development of showers and thunderstorms through at least late
Tuesday night. As the wave moves westward and away from the local
islands, a somewhat drier air mass will invade the local area on
Wednesday and Thursday. Despite that, model guidance suggests
that an upper level low and associated trough will expand west-
southwestward over the western Atlantic Ocean and place itself to
the northwest of the region during the second part of next week.
Although this could bring favorable upper level dynamics across
the region, there is a low confidence level since this takes place
far in the forecast period.

&&

.AVIATION...SHRA/TSRA expected today across the local area will
cause at least VCSH/VCTS across the local terminals for the next 24
hours. TSRA is expected to affect some of the terminals, especially
TJSJ. However, given considerable uncertainty on exact location,
timing, and intensity of the TSRA, no TEMPO groups were written on
TAF, but rest assured that active weather is expected today. Winds
will be from the east today at 10 to 15 knots and gusty, especially
near SHRA/TSRA.


&&

.MARINE...A small craft advisory is in effect for the offshore
Atlantic waters through 8 AM AST this morning due to wind driven seas
up to 7 feet resulting from the passage of a tropical wave.
Elsewhere, small craft operators are urged to exercise caution due
to seas up to 6 feet and east winds up to 20 knots with higher
gusts. There is a moderate risk of rip currents for most of the
east, north and southern beaches of the islands.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 87 76 85 77 / 80 70 70 20
STT 88 79 89 79 / 60 60 40 20
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Re: Caribbean - Central America Weather

#19553 Postby cycloneye » Fri Aug 31, 2018 4:58 am

Area Forecast Discussion
National Weather Service San Juan PR
436 AM AST Fri Aug 31 2018

.SYNOPSIS...Tropical wave will continue to pass over the local
area today and interact with an upper trough. This will result
once again in showers and thunderstorms across the local area
today. Surface high pressure across the central Atlantic will
keep promoting an easterly wind flow for the next several days.
Another tropical wave is expected on Monday and a TUTT is expected
to position itself just north of the local islands on Tuesday.

&&

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

Lingering low level moisture from a departing tropical wave and
favorable upper level dynamics due to a TUTT north of the area will
continue to enhance deep convection across the forecast area. Early
morning shower activity expected over portions of eastern Puerto
Rico, the U.S. Virgin Island and surrounding waters, with the
possibility of isolated thunderstorms over Atlantic waters and the
Mona Passage. Discrepancies among the main models is reflected in
the intensity and coverage on the afternoon activity. Both ARW and
WRF place the activity across most of the forecast area, whereas the
NMM and GFS appears more conservative with the most intense activity
over the islands and across the northwest quadrant of the forecast
area. The latter solution was the preferred choice as mid- to upper-
level cloudiness is expected to diminish during the morning hours
allowing diurnal effects to come into play. As a result, the threat
of urban and small stream flooding, as well as rapid rises along
rivers and mudslides remains possible on Friday.

Once the low level moisture erodes and the TUTT lifts north, a mid-
to upper-level short wave ridge will become the dominant feature
across the local area. Thus, a more seasonal and drier weather
pattern will return to the forecast area on Saturday and Sunday.
That is, overnight and early morning showers streaming over eastern
Puerto Rico and the Virgin Isles, followed by locally induced
convection over the interior and western Puerto Rico in the
afternoon. Streamer-like showers off El Yunque and the local islands
are also possible each afternoon. Nevertheless, rainfall
accumulations of up to an inch is forecast for each day.

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

Another tropical wave is expected to move in on Monday, which will
once again cause an increase in moisture and likely in shower and
thunderstorm activity across the local islands. There is also a
possible TUTT in the area which may position itself in a favorable
position for thunderstorm support over the local area by Tuesday,
which is a day after the tropical wave. If the timing on the model
guidance is correct, there may be lingering moisture on Tuesday,
which could combine with diurnal heating and the TUTT to cause
showers and thunderstorms over the local area. Thereafter, drier
air moves in but the TUTT moves to our NW, which may still help in
the development of showers and thunderstorms, especially in the
afternoon hours when diurnal heating and local effects combine
with the divergence aloft. Whether or not another tropical wave
will reach the local area late next week will depend on their
development across the Atlantic, if any. This is late in the
forecast period so the confidence is low.


&&

.AVIATION....VCSH expected across the local terminals, except
TNCM/TKPK with VCTS until 31/13Z. Afternoon convection will result
in VCTS across TJSJ/TJPS and SHRA/VCTS at TJMZ/TJBQ. Given
considerable uncertainty on the timing of SHRA/TSRA occurrence,
no TEMPO groups were added at this time. However, active weather
is expected today. Winds will be from the east today at 10 to 15
knots with higher gusts, especially near the SHRA/TSRA.

&&

.MARINE...Small craft operators are urged to exercise caution as
seas will be up to 6 feet today and winds up to 20 knots. By
tonight, the winds and seas are expected to diminish slightly
across most areas but seas may still be choppy.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 87 76 88 78 / 40 20 20 40
STT 85 76 90 79 / 40 20 20 40
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Re: Caribbean - Central America Weather

#19554 Postby cycloneye » Sat Sep 01, 2018 5:32 am

Area Forecast Discussion
National Weather Service San Juan PR
436 AM AST Fri Aug 31 2018

.SYNOPSIS...Tropical wave will continue to pass over the local
area today and interact with an upper trough. This will result
once again in showers and thunderstorms across the local area
today. Surface high pressure across the central Atlantic will
keep promoting an easterly wind flow for the next several days.
Another tropical wave is expected on Monday and a TUTT is expected
to position itself just north of the local islands on Tuesday.

&&

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

Lingering low level moisture from a departing tropical wave and
favorable upper level dynamics due to a TUTT north of the area will
continue to enhance deep convection across the forecast area. Early
morning shower activity expected over portions of eastern Puerto
Rico, the U.S. Virgin Island and surrounding waters, with the
possibility of isolated thunderstorms over Atlantic waters and the
Mona Passage. Discrepancies among the main models is reflected in
the intensity and coverage on the afternoon activity. Both ARW and
WRF place the activity across most of the forecast area, whereas the
NMM and GFS appears more conservative with the most intense activity
over the islands and across the northwest quadrant of the forecast
area. The latter solution was the preferred choice as mid- to upper-
level cloudiness is expected to diminish during the morning hours
allowing diurnal effects to come into play. As a result, the threat
of urban and small stream flooding, as well as rapid rises along
rivers and mudslides remains possible on Friday.

Once the low level moisture erodes and the TUTT lifts north, a mid-
to upper-level short wave ridge will become the dominant feature
across the local area. Thus, a more seasonal and drier weather
pattern will return to the forecast area on Saturday and Sunday.
That is, overnight and early morning showers streaming over eastern
Puerto Rico and the Virgin Isles, followed by locally induced
convection over the interior and western Puerto Rico in the
afternoon. Streamer-like showers off El Yunque and the local islands
are also possible each afternoon. Nevertheless, rainfall
accumulations of up to an inch is forecast for each day.

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

Another tropical wave is expected to move in on Monday, which will
once again cause an increase in moisture and likely in shower and
thunderstorm activity across the local islands. There is also a
possible TUTT in the area which may position itself in a favorable
position for thunderstorm support over the local area by Tuesday,
which is a day after the tropical wave. If the timing on the model
guidance is correct, there may be lingering moisture on Tuesday,
which could combine with diurnal heating and the TUTT to cause
showers and thunderstorms over the local area. Thereafter, drier
air moves in but the TUTT moves to our NW, which may still help in
the development of showers and thunderstorms, especially in the
afternoon hours when diurnal heating and local effects combine
with the divergence aloft. Whether or not another tropical wave
will reach the local area late next week will depend on their
development across the Atlantic, if any. This is late in the
forecast period so the confidence is low.


&&

.AVIATION....VCSH expected across the local terminals, except
TNCM/TKPK with VCTS until 31/13Z. Afternoon convection will result
in VCTS across TJSJ/TJPS and SHRA/VCTS at TJMZ/TJBQ. Given
considerable uncertainty on the timing of SHRA/TSRA occurrence,
no TEMPO groups were added at this time. However, active weather
is expected today. Winds will be from the east today at 10 to 15
knots with higher gusts, especially near the SHRA/TSRA.

&&

.MARINE...Small craft operators are urged to exercise caution as
seas will be up to 6 feet today and winds up to 20 knots. By
tonight, the winds and seas are expected to diminish slightly
across most areas but seas may still be choppy.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 87 76 88 78 / 40 20 20 40
STT 85 76 90 79 / 40 20 20 40
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Re: Caribbean - Central America Weather

#19555 Postby cycloneye » Sun Sep 02, 2018 6:29 am

Area Forecast Discussion
National Weather Service San Juan PR
437 AM AST Sun Sep 2 2018

.SYNOPSIS...Surface high pressure across the central Atlantic will
continue to promote an easterly wind flow for the next several
days. Weak ridge aloft today should slowly erode by Monday, then
an upper low to the north of the local islands will move west
southwest and dig into the Hispaniola by Tuesday afternoon,
causing an increase in upper level instability. Drier air is
expected today just before a tropical wave which is expected to
move in on Monday, with moisture lingering into Tuesday.


&&

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

The easterly winds promoted by a surface high pressure across the
Central Atlantic brought a patch of moisture ahead of the tropical
wave overnight, which produce numerous showers across Puerto Rico
and the U.S. Virgin Islands. This showers are expected to slowly
diminish through the morning hours, as satellite imagery depicted an
area of dry air mass, which is expected to filters later this
morning limiting shower activity. However, the low pressure, south
of Hispanola, will weaken the ridge aloft, increasing local
instability. As a result, locally induced afternoon convection is
expected to develop across the interior and in western Puerto Rico
today.

The easterly wave, expected to reach the islands late tonight into
Monday, will pool tropical moisture across the islands through at
least Tuesday. In addition, model guidance suggested divergence
aloft associated with a TUTT low (located off to the northeast of
the islands), which combined with the available moisture could
increase the potential for showers and thunderstorm development
early this week. By Wednesday, a dry air mass is forecast to filters
from the east across the islands limiting the formation of shower
activity, but the typical weather pattern could not be ruled out.

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

Note...The weather pattern in the long range may be influenced by
the intensity and trajectory of Tropical Storm Florence and the
development, if any, of the other tropical waves leaving the west
coast of Africa, making our confidence in the long range forecast
lower than normal. The global model guidance available for
Florence and the tropics in general varies considerably for this
time period. The Tropical Cyclone Discussion issued by the
National Hurricane Center has more details on Florence. One thing
all of the model guidance agrees on is that Florence is expected
to remain well north of the local area.

After the tropical wave passes early in the week, drier air is
expected to move in starting on Wednesday. Overall moisture is
expected to be near normal for the second half of the workweek
with much drier air moving in for the weekend. An upper trough
currently north of the local islands will have strengthened and
moved just north of Hispaniola by Wednesday as it continues to
move west. The upper trough may contribute to thunderstorm support
over Puerto Rico on Wednesday and perhaps on Thursday, as the
diurnal heating and local effects combine with the upper level
dynamics. The upper low should be a bit too far west by Friday,
and a weak upper high pressure will remain over the local islands
from Friday through Monday, causing a more stable atmosphere while
even drier air also moves in.

&&

.AVIATION...VFR conditions will persist across the flying area,
except between 02/16z-22z when SHRA/+TSRA are expected along the
Cordillera Central which could impact TJMZ producing MVFR conds.
VCTS are psbl at TJBQ and TJSJ as well. Sfc winds will continue calm
to light and variable til around 02/13z, when easterly winds will
return at 10 to 20 kt with higher gusts and sea breeze variations.

&&

.MARINE...Seas will remain choppy for the next several days with
wave heights up to 5 feet. Winds across the waters will be
generally between 10 and 15 knots but some areas in the coastal
Atlantic and Caribbean waters may observe winds up to 20 knots. A
long period swell may invade the local waters late this week.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 88 79 87 78 / 30 60 60 50
STT 90 79 88 80 / 30 60 60 60
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Re: Caribbean - Central America Weather

#19556 Postby cycloneye » Mon Sep 03, 2018 5:50 am

Area Forecast Discussion
National Weather Service San Juan PR
512 AM AST Mon Sep 3 2018

.SYNOPSIS...
The trailing moisture of the tropical wave will continue to bring
passing showers across the windward sections through the morning
hours. This moisture will combined with the instability associated
with a TUTT to the northeast of the islands and local effects to
result in afternoon convection mainly in west Puerto Rico, and in
the form of streamers downwind from the U.S. Virgin Islands and
from El Yunque. The TUTT will increase local instability through
at least Wednesday.

&&

.SHORT TERM...Today through Wednesday...
Latest surface analysis showed a tropical wave over the Northeast
Caribbean this morning. In addition, an upper level trough/TUTT
north-northeast of Puerto Rico is inducing a surface trough near
60W/20N. Both features will favor moisture transport across the
local area today. As a result...precipitable water values will surge
to 2 inches around later this morning. With high moisture content
and unstable environment due to proximity of the upper trough, the
local area will be experiencing a few rounds of convection through
this afternoon. Periods of heavy rainfall are expected at times,
with the highest rainfall accumulation focusing over El Yunque area
and northwest Puerto Rico in the afternoon.

Drier and more stable air mass will filter in across the Northeast
Caribbean tonight and Tuesday morning, limiting the shower coverage
across the local region. Then, an induce surface trough will cross
the USVI and Puerto Rico late Tuesday into Wednesday morning,
increasing again the shower and thunderstorm activity as the upper
level trough swings across Hispanola. Afternoon convection on
Wednesday will be focused over the northwest quadrant of Puerto
Rico.

.LONG TERM...Thursday through Tuesday...
The islands will lie between an upper level low to the
northwest (near the Bahamas islands) and an upper level high
moving across the eastern Caribbean Sea, which is expected to
build across the islands by the upcoming weekend and hold through
at least early Monday morning. At low levels, a drier air mass
with patches of moisture will persist through this period.
Under this stable weather pattern, expect the typical overnight
and early passing showers across the windward sections of Puerto
Rico and the U.S. Virgin Islands, followed by afternoon convection
across the interior and west portion of Puerto Rico as well as
downwind from the U.S. Virgin Islands.

The weather pattern for next week may be influenced by the
evolution of Tropical Cyclone Florence, which is forecast to
move well north of the local area into the western Atlantic Ocean.
Based on the current track of Florence, long period northeast
swell could impact the north and east coast of Puerto Rico and the
U.S. Virgin Islands. Model guidance continues to suggest
discrepancies with the development of the other tropical waves
leaving the African coast by early next week and making its way
into the Atlantic Ocean by mid week.

&&

.AVIATION...SHRA and TSRA in route from Leeward Islands to Puerto
Rico associated with the tropical wave. As a result, MVFR conds are
possible with SHRA at TNCM/TKPK through 14Z, TIST/TISX through 16Z
and TJMZ/TJBQ between 16Z-21Z. ESE winds of 15-20 kts below FL200.

&&

.MARINE...
Seas across the protected waters should range between 2 and 4 feet
and between 3 and 5 feet across the Offshore waters. The winds are
forecast to continue from the east at 10 to 15 knots and locally
higher in and around shower activity. Thunderstorms development is
expected during the afternoon hours across the western coastal
waters of Puerto Rico.

Based on the latest track of Florence, a long period northeast
swell is expected to move across the local Atlantic Waters and
Caribbean Passages by the end of the work week.

A moderate risk of rip currents will continue mainly across the
northern coast of Puerto Rico, and some beaches across Culebra
and St Croix.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 89 79 91 80 / 60 40 30 20
STT 89 80 88 80 / 60 40 30 30
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Re: Caribbean - Central America Weather (Watching INVEST 92L)

#19557 Postby cycloneye » Mon Sep 03, 2018 6:25 pm

8 PM TWO:

A tropical wave located a few hundred miles southeast of the Cabo
Verde Islands continues to produce a large area of disorganized
showers and thunderstorms. Gradual development of this system is
expected, and it could become a tropical depression late this week
or this weekend while it moves westward to west-northwestward across
the eastern tropical Atlantic.
* Formation chance through 48 hours...low...10 percent.
* Formation chance through 5 days...medium...50 percent.


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Re: Caribbean - Central America Weather (Watching INVEST 92L)

#19558 Postby cycloneye » Tue Sep 04, 2018 6:17 am

Area Forecast Discussion
National Weather Service San Juan PR
512 AM AST Mon Sep 3 2018

.SYNOPSIS...
The trailing moisture of the tropical wave will continue to bring
passing showers across the windward sections through the morning
hours. This moisture will combined with the instability associated
with a TUTT to the northeast of the islands and local effects to
result in afternoon convection mainly in west Puerto Rico, and in
the form of streamers downwind from the U.S. Virgin Islands and
from El Yunque. The TUTT will increase local instability through
at least Wednesday.

&&

.SHORT TERM...Today through Wednesday...
Latest surface analysis showed a tropical wave over the Northeast
Caribbean this morning. In addition, an upper level trough/TUTT
north-northeast of Puerto Rico is inducing a surface trough near
60W/20N. Both features will favor moisture transport across the
local area today. As a result...precipitable water values will surge
to 2 inches around later this morning. With high moisture content
and unstable environment due to proximity of the upper trough, the
local area will be experiencing a few rounds of convection through
this afternoon. Periods of heavy rainfall are expected at times,
with the highest rainfall accumulation focusing over El Yunque area
and northwest Puerto Rico in the afternoon.

Drier and more stable air mass will filter in across the Northeast
Caribbean tonight and Tuesday morning, limiting the shower coverage
across the local region. Then, an induce surface trough will cross
the USVI and Puerto Rico late Tuesday into Wednesday morning,
increasing again the shower and thunderstorm activity as the upper
level trough swings across Hispanola. Afternoon convection on
Wednesday will be focused over the northwest quadrant of Puerto
Rico.

.LONG TERM...Thursday through Tuesday...
The islands will lie between an upper level low to the
northwest (near the Bahamas islands) and an upper level high
moving across the eastern Caribbean Sea, which is expected to
build across the islands by the upcoming weekend and hold through
at least early Monday morning. At low levels, a drier air mass
with patches of moisture will persist through this period.
Under this stable weather pattern, expect the typical overnight
and early passing showers across the windward sections of Puerto
Rico and the U.S. Virgin Islands, followed by afternoon convection
across the interior and west portion of Puerto Rico as well as
downwind from the U.S. Virgin Islands.

The weather pattern for next week may be influenced by the
evolution of Tropical Cyclone Florence, which is forecast to
move well north of the local area into the western Atlantic Ocean.
Based on the current track of Florence, long period northeast
swell could impact the north and east coast of Puerto Rico and the
U.S. Virgin Islands. Model guidance continues to suggest
discrepancies with the development of the other tropical waves
leaving the African coast by early next week and making its way
into the Atlantic Ocean by mid week.

&&

.AVIATION...SHRA and TSRA in route from Leeward Islands to Puerto
Rico associated with the tropical wave. As a result, MVFR conds are
possible with SHRA at TNCM/TKPK through 14Z, TIST/TISX through 16Z
and TJMZ/TJBQ between 16Z-21Z. ESE winds of 15-20 kts below FL200.

&&

.MARINE...
Seas across the protected waters should range between 2 and 4 feet
and between 3 and 5 feet across the Offshore waters. The winds are
forecast to continue from the east at 10 to 15 knots and locally
higher in and around shower activity. Thunderstorms development is
expected during the afternoon hours across the western coastal
waters of Puerto Rico.

Based on the latest track of Florence, a long period northeast
swell is expected to move across the local Atlantic Waters and
Caribbean Passages by the end of the work week.

A moderate risk of rip currents will continue mainly across the
northern coast of Puerto Rico, and some beaches across Culebra
and St Croix.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 89 79 91 80 / 60 40 30 20
STT 89 80 88 80 / 60 40 30 30
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Re: Caribbean - Central America Weather (Watching INVEST 92L)

#19559 Postby cycloneye » Tue Sep 04, 2018 6:18 am

8 AM TWO:

A tropical wave accompanied by a broad low pressure system located
a few hundred miles south-southeast of the Cabo Verde Islands is
forecast to move slowly westward to west-northwestward across the
eastern tropical Atlantic for the next several days. Although this
disturbance continues to produce disorganized showers and
thunderstorms, environmental conditions are expected to gradually
become conducive for further development, and a tropical depression
is likely to form by late this week or this weekend.
* Formation chance through 48 hours...low...20 percent.
* Formation chance through 5 days...high...70 percent.


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Re: Caribbean - Central America Weather (Watching INVEST 92L)

#19560 Postby cycloneye » Tue Sep 04, 2018 12:42 pm

2 PM TWO= 30%/80%

A broad low pressure system located a few hundred miles south of
the Cabo Verde Islands is forecast to move slowly westward to
west-northwestward across the eastern tropical Atlantic for the next
several days. Environmental conditions are expected to gradually
become more conducive for development, and a tropical depression is
likely to form by late this week or this weekend.
* Formation chance through 48 hours...low...30 percent.
* Formation chance through 5 days...high...80 percent.


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