Caribbean - Central America Weather

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cycloneye
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Re: Caribbean - Central America Weather

#19901 Postby cycloneye » Sat Jul 06, 2019 5:26 am

Area Forecast Discussion
National Weather Service San Juan PR
448 AM AST Sat Jul 6 2019

.SYNOPSIS...A drier and more stable weather pattern along with
some Saharan dust will prevail throughout the weekend. Afternoon
convection is still expected across western Puerto Rico during the
afternoon hours. Another tropical wave is still expected to
affect the area late Monday into Tuesday, resulting an increase in
shower and thunderstorm activity. More stable weather conditions
will follow by the middle and latter half of the work week.

&&

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

A dry air mass with Saharan air particles will move across the
islands today. Model guidance continues to indicate stable weather
conditions through the rest of the weekend. However, moisture
embedded in the trades will bring passing showers across the local
waters at times. Showers and thunderstorms will develop across the
western sections of Puerto Rico due to the strong daytime heating
and sea breeze convergence. Local effects will aid in the
development of showers downwind from the U.S. Virgin Islands each
afternoon.

Daytime high temperatures are forecast to peak in the upper 80s to
low 90s along coastal areas, and in the upper 70s to mid 80s at
higher elevations each day. The Virgin Islands will observe heat
indices in the low and to mid 100s today.

An upper-level trough will slowly dig into the region increasing
instability by late Sunday night into Monday. This upper level
feature will interact with the leading edge of a tropical wave,
which is forecast to reach the islands by late Monday night or early
Tuesday. This will increase the intensity and frequency of showers
and thunderstorms across the area.

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

The axis of the tropical wave is still on track to move across
the area on Tuesday with precipitable water values approaching 2
inches. At the same time, an upper-level trough will be located
just north of Haiti. Therefore, this upper-level trough could aid
in enhancing the rainfall activity that this wave brings. The
tropical wave departs by Tuesday night and behind it, a drier air
mass follows for Wednesday.

For Thursday through Saturday, patches of low-level moisture
embedded within the easterlies will be moving across the area.
Therefore, some passing showers may affect the regional waters and
eastern portions of Puerto Rico and the USVI during the overnight
and morning hours followed by convection developing across
western Puerto Rico during the afternoon hours as a result of
daytime heating and local effects.

&&

.AVIATION...VFR conditions expected throughout the day. SHRA/TSRA
are expected to develop over western Puerto Rico between 06/16-22z.
This may impact JMZ. Winds less than 10 knots through 06/13z,
increasing around 15 knots from the E with higher gusts and sea
breeze variations after 06/13z.

&&

.MARINE...Moderate to fresh easterly trades between 15 and 20
knots will continue to result in rough and choppy seas across
the regional waters through this afternoon. A small craft
advisory continues in effect through 8 am this morning for the
offshore Atlantic waters and through 2 pm this afternoon for the
offshore Caribbean waters and Mona Passage due to seas of up to 7
feet. Seas of up to 6 feet are expected across the nearshore
Atlantic and Caribbean waters. More tranquil seas are expected by
this evening through Monday as the winds diminish.

For beachgoers, there is a moderate risk of rip currents for most
of the local beaches of the islands, except along the west coast
of Puerto Rico and along the northern coast of Saint Thomas and
Saint John.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 89 78 89 78 / 0 30 30 50
STT 90 79 90 79 / 10 40 30 50
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Re: Caribbean - Central America Weather

#19902 Postby cycloneye » Sun Jul 07, 2019 5:07 am

Area Forecast Discussion
National Weather Service San Juan PR
442 AM AST Sun Jul 7 2019

.SYNOPSIS...Moisture will increase through Tuesday as an easterly
perturbation and a tropical wave move across the eastern
Caribbean. This will result in an increase in shower and
thunderstorm activity across portions of the local area. A drier
air mass is expected on Wednesday. Then, during the latter half of
the work week and into next weekend, occasionally patches of low-
level moisture embedded within the easterlies will move across the
area.

&&

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

Model guidance are indicating a wetter pattern through early this
week. A TUTT Low is forecast to drift into the region from the
northeast increasing somewhat the local instability through the
short-term period. Moisture embedded in the trades will bring
occasional passing showers across the local waters, the U.S.
Virgin Islands and the eastern half of Puerto Rico through the
morning hours. Showers and thunderstorms will develop across the
western sections of Puerto Rico due to the strong daytime heating,
local effects and sea breeze convergence. Local effects will aid
in the development of showers downwind from the U.S. Virgin
Islands. Once again, high temperatures are forecast to peak in the
upper 80s to low 90s along coastal areas, and in the upper 70s to
mid 80s at higher elevations each this afternoon.

As the TUTT-low amplifies northwest of the islands, instability
is expected to increase through Tuesday. This upper level feature
will interact with an easterly perturbation, increasing the
intensity and frequency of showers and thunderstorms on Monday. A
tropical wave is forecast to move across the region by Tuesday.
Under this wetter pattern, the potential for urban and small
stream flooding will be moderate-high each afternoon.

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

A drier air mass is expected to move across the area on Wednesday,
resulting in a decrease in shower activity. Then, during the
latter half of the work week and into next weekend, patches of
low- level moisture embedded within the easterly trade wind flow
will move across the area from time to time. This will result in
some passing showers affecting the regional waters, eastern
portions of Puerto Rico, and the USVI mainly during the overnight
and morning hours followed by convection developing across the
western half of Puerto Rico during the afternoon hours as a result
of daytime heating and local effects. At this time, widespread
significant rainfall activity that would alleviate the current
drought situation is not expected during the long-term period.

&&

.AVIATION...VFR conditions expected throughout the day.
Passing SHRA will move at times over JSJ/IST/ISX through the morning
hours. SHRA/TSRA are expected to develop over the interior/western
Puerto Rico between 07/16-22z. This may impact JMZ/JBQ and the
vicinity of JPS. Winds less than 10 knots through 07/13z, increasing
around 15 knots from the E with higher gusts and sea breeze
variations after 07/13z.

&&

.MARINE...Tranquil marine conditions are expected for today and
Monday with seas ranging between 2 and 5 feet and east winds up
to 15 knots. However, across the Atlantic waters just north of
Puerto Rico, winds near 20 knots are possible late in the morning
and into the afternoons hours due to local effects. Therefore,
small craft operators should exercise caution. Winds and seas will
increase by late Monday night and Tuesday as a tropical wave
moves across the area.

There is a moderate risk of rip currents for some of the northern
and southern beaches of Puerto Rico as well as for Cramer Park
beach in Saint Croix. Elsewhere, the rip current risk will be
low.


&&

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

#19903 Postby cycloneye » Mon Jul 08, 2019 4:54 am

Area Forecast Discussion
National Weather Service San Juan PR
520 AM AST Mon Jul 8 2019

.SYNOPSIS...
A wetter pattern will persist today and tomorrow due to an
approaching tropical wave. A TUTT-low will move further west over
the Hispaniola through at least Wednesday. Therefore, an increase
in shower and thunderstorm activity is expected today and Tuesday.
The arrival of a drier air mass with Saharan dust particles is
expected late Tuesday night into Wednesday. By the second part of
the work-week, patches of moisture embedded in the trades will
move across the area. A tropical wave is forecast to move across
the Caribbean water by the Saturday.

&&

.Short Term...Today through Wednesday...

Variably cloudy skies prevailed across the local islands during the
overnight hours with frequent passing showers observed over eastern
Puerto Rico and the outlying islands. Rainfall accumulations
associated with these showers, however, were minimal. Winds were
southeasterly at 10 mph or less with overnight minimum temperatures
in the upper 70s at lower elevations.

Trofiness aloft will continue to prevail across the forecast area
through at least Tuesday. As the TUTT aloft moves further west, a
mid to upper level ridge will strengthen across the local islands by
Wednesday morning. At lower levels, an approaching tropical wave
will advect moisture later today through at least Tuesday morning
with precipitable water values near 1.70 inches, which is near the
normal range for the month of July. Moderate southeasterly winds to
continue through Tuesday becoming more easterly Wednesday onwards.

The moisture associated with the approaching tropical wave will
combine with ventilation provided by the TUTT to our west to enhance
shower and thunderstorm activity across the forecast area today
through Tuesday morning. Lingering moisture will be enough on
Tuesday afternoon to produce another round of showers. Therefore,
expect passing showers across the US Virgin Islands and the eastern
third of Puerto Rico early this morning followed by the development
of showers and thunderstorms across the northern slopes of Puerto
Rico in the afternoon. Although this shower and thunderstorm
activity is expected to dissipate by the evening hours, showers and
isolated thunderstorms will continue to affect the eastern third of
Puerto Rico as well as the outlying islands overnight. Weather
conditions are expected to improve Tuesday afternoon with showers
and isolated thunderstorms focused over northwest Puerto Rico. By
Wednesday, a drier and more stable air mass is expected to move in
with some Saharan dust to result in limited shower activity.

.LONG TERM...Thursday through Monday...
Model guidance is suggesting the arrival of surges of moisture
embedded in the easterly trades each day through the long term
forecast. A band of low-level moisture will increase PW values
between 1.50 and 1.90 inches by Thursday morning, but it will be
followed by another patch of dry air. Therefore, if models are
correct, a brief increase in showers should be expected Thursday
morning.

A tropical wave is forecast to move off to the south, across the
Caribbean waters by Saturday. Although model guidance has the bulk
of moisture well south of the islands, a slight increase in the
available moisture would be possible.

By the end of the forecast cycle, a mid-upper level trough will
drift near the region. At this time, widespread significant
rainfall activity that would alleviate the current drought
situation is not expected during the long-term period.

&&

.AVIATION...
Brief periods of MVFR conds will remain possible in SHRA/TSRA at
the Leeward, USVI and TJSJ TAF sites through the morning hours.
Aft 08/16z TSRA likely to affect JSJ/JBQ through at least 08/22z.
Southeasterly winds 10-15 knots with higher gusts and sea breeze
variations to continue.

&&

.MARINE...
Mariners can expect tranquil marine conditions with seas between 1
and 4 feet across protected waters and between 3 and 5 feet across
expose waters. The approaching tropical wave will increase winds
and seas at 15 to 20 knots, and between 4 and 6 feet across the
Caribbean Waters and local passages late Monday into Tuesday,
respectively.

In general, tranquil marine conditions will persist after Tuesday.
However, model guidance are suggesting an increase in wind and
seas by Saturday as a tropical wave moves well south across the
Caribbean Sea.

For the beach goers, there is a moderate risk of rip currents for
the beaches of St Croix today. Elsewhere, the risk is low.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 90 79 91 79 / 60 40 30 30
STT 88 81 89 80 / 60 50 50 30
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Re: Caribbean - Central America Weather

#19904 Postby cycloneye » Tue Jul 09, 2019 5:01 am

Area Forecast Discussion
National Weather Service San Juan PR
457 AM AST Tue Jul 9 2019

.SYNOPSIS...
Several opportunities for precipitation exist over the next week,
but nothing of major consequence that will aid in drought relief.
Showers are expected again today, primarily over northwestern
Puerto Rico in the afternoon hours. A drier airmass moves in for
Wednesday and Thursday, with another round of Saharan dust.
Isolated showers are possible into the weekend, with another
tropical wave arriving for Saturday night and through Sunday.

&&

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

Partly cloudy skies prevailed across the local islands during the
overnight hours with passing showers observed over the Caribbean
waters. A few of these showers were observed over land areas as
well, however, rainfall accumulations were minimal. Winds were
southeasterly at 10 mph or less with overnight minimum temperatures
in the upper 70s and low 80s at the lower elevations.

As the TUTT aloft moves further west, a mid to upper level ridge
will strengthen across the local islands to result in fair and
stable weather conditions Wednesday and Thursday. Meanwhile,
throughout the day today, lingering moisture associated with a
departing tropical wave will continue to combine with the TUTT aloft
to result in showers and thunderstorms over northwest Puerto Rico in
the afternoon. Enhanced shower activity could be also observed over
the Caribbean waters during the morning hours. These showers may
reach the eastern third of Puerto Rico as well as the outlying
islands. Significant rainfall accumulations, however, are not
expected at this time. There is another tropical wave which is
expected to move well south of the area later today into Wednesday.

Under the aforementioned pattern, the chance for showers and
thunderstorms continues today, decreasing Wednesday and Thursday as
the drier and stable air mass moves in from the east. Locally
induced afternoon showers cant be ruled out Wed-Thu as the result of
diurnal heating and sea breeze convergence. Haziness associated with
African dust is also expected Wed-Thu. Under southeasterly winds,
maximum temperatures will continue to range in the upper 80s to low
90s at the lower elevations.

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

A mid upper level high pressure will hold through at least
Saturday. A fair weather pattern is expected to persist, but
patches of low-level moisture will bring passing showers across
the windward sections of PR/USVI during the morning and overnight
hours. Local effects and diurnal heating will produce afternoon
convection across western PR.

Now, model guidance suggests the tropical wave moving closer to
the islands Saturday evening into Sunday. If model are correct,
expect an increase in showers and thunderstorms through this
period.

By the end of the forecast cycle, a mid-upper level ridge will
drift near the region. At this time, widespread significant
rainfall activity that would alleviate the current drought
situation is not expected during the long-term period.

&&

.AVIATION...
VCSH likely at the Leeward and USVI terminals as well as JSJ
through the morning hours. Aft 09/16z TSRA likely to affect JBQ
through at least 09/22z, resulting in periods of MVRF conds.
Southeasterly winds at around 15 knots with higher gusts and sea
breeze variations to continue.

&&

.MARINE...
Seas and waves are forecast to increase somewhat across the
local waters, especially across the Caribbean Sea, as the
tropical wave swing by the region. Mariner can expect seas between
4 and 6 feet and winds between 15 and 20 knots. Small craft
operators should exercise caution.

Seas are forecast to improve after Wednesday but are forecast to
increase once again by the weekend. If marine guidance are
correct, Small-Craft-Advisory conditions are possible over the
upcoming weekend in the Offshore Caribbean waters.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 90 80 90 79 / 20 10 20 30
STT 90 80 89 79 / 50 20 20 30
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Re: Caribbean - Central America Weather

#19905 Postby cycloneye » Wed Jul 10, 2019 4:50 am

Area Forecast Discussion
National Weather Service San Juan PR
400 AM AST Wed Jul 10 2019

.SYNOPSIS...

Drier weather will take hold across the region into the weekend,
with Saharan dust and hazy conditions returning. However,
isolated showers are expected for especially western Puerto Rico.
Our next best chance for widespread showers will be late Saturday
and into Sunday as a tropical wave will move through the region.
Drier air and Saharan dust will be with us to start the next work
week.


&&

.Short Term...Today through Friday...

Clear to partly cloudy skies and rain-free conditions prevailed
across the local islands during the overnight hours. Winds were
southeasterly at 10 mph or less with overnight minimum temperatures
in the upper 70s to low 80s at the lower elevations.

200 MB heights will continue to rise and precipitable water values
will continue to decrease as a ridge pattern aloft strengthens. This
feature is expected to hold today and Thursday with some weakening
expected by Friday. At lower levels, east southeast winds to
continue today, becoming more east northeast on Thursday.

Therefore, dry and stable weather conditions are expected to prevail
through the end of the work-week. Showers, if any, will be
focused across west Puerto Rico each afternoon. Haziness
associated with African dust to continue through at least
Thursday. Under southeasterly winds, maximum temperatures will
continue to range in the low to mid 90s at the lower elevations.
As the winds shift east northeast, a relief is expected with
temperatures ranging in the upper 80s to low 90s.

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

A tropical wave is forecast to cross the Windward Islands on
Saturday, and will move near the U.S. Virgin Islands and Puerto
Rico between Saturday night and early Sunday morning. Both, GFS
and ECMWF agree on the arrival of this wave, which seems to be
the best chance for showers and thunderstorms development through
the forecast period. A dry air mass with Saharan dust particles is
forecast arriving after the passage of this wave by Sunday
afternoon. In addition, a mid to upper level ridge will promote
hostile environmental conditions for the development of organize
convection early next week. However, moisture embedded in the
trades will bring quick passing showers across the windward
sections each day and night followed by limited afternoon
convection over west Puerto Rico.

&&

.AVIATION...VFR conds are expected to prevail at all TAF sites
with VCSH possible at JBQ aft 10/16z. Southeasterly winds at around
15 knots with higher gusts and sea breeze variations to continue.
Hazy, although visibilities are expected to remain P6SM.

&&

.MARINE...

Seas less than 6 feet are expected for the rest of the week, with
winds less than twenty knots from the east to east-southeast. As
our next tropical wave rolls in Sunday, seas are expected to reach
and even possibly exceed 7 feet, with winds gusting well into the
20`s. A moderate risk of rip currents exits for most beaches in
Puerto Rico, as well as the surrounding islands.

&&


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 90 79 87 78 / 20 30 30 30
STT 89 79 89 77 / 20 30 30 30
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Re: Caribbean - Central America Weather

#19906 Postby cycloneye » Thu Jul 11, 2019 4:57 am

Area Forecast Discussion
National Weather Service San Juan PR
525 AM AST Thu Jul 11 2019

.SYNOPSIS...Locally induced afternoon showers with isolated
thunderstorms possible are expected much of the forecast cycle.
Bulk of moisture associated with tropical wave passages will
continue to remain mainly south of the forecast area.

&&

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

SFC high pressure north of the local islands will promote an east to
east northeast wind flow today into Friday, but will be mainly
easterly on Saturday. Weak upper level low over the local islands
may cause some subsidence due to the positioning of the low pressure
system. However, it is slowly moving west and it is more favorable
for upper level instability on Friday, providing support for
thunderstorm development. The upper low continue to move west and
more subsidence is expected on Saturday, even though a tropical wave
is expected to move south of the local area on Saturday into Sunday.
The temperatures will be near normal for the next few days across
the local islands.

All this means that essentially the main cause of rainfall over the
local islands would be locally induced showers, mainly across
portions of western PR, while the rest of the area will have brief
isolated to scattered showers. Drier air is moving in today, which
will limit the shower development across western to southwestern PR
this afternoon. Then on Friday afternoon, the aforementioned upper
low may be in a better position to enhance convection across western
PR when the local effects combine with the diurnal heating. There is
a tropical wave moving in late on Saturday, but the latest guidance
indicates that the moisture will be to our south and the upper
levels will not provide support for convection so the shower
activity is expected to be limited over land, most of the shower
activity is expected over the Caribbean waters.

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

As the tropical wave moves away from the eastern Caribbean on
Sunday morning, a drier and more stable airmass is expected to
encompass the forecast area. This airmass is expected to hold
across the eastern Caribbean much of the cycle. As matter of fact,
latest guidance suggested precipitable water values well below
the normal range - which is 1.75 inches - through at least the end
of the work week. There is a tropical wave passage early in the
cycle, but bulk of moisture is expected to remain south of the
forecast area. A second tropical wave passage is expected by
Friday with precipitable water values near or above the normal
range.

Therefore, lingering moisture associated with the departing tropical
wave will combine with sea breeze convergence to result in showers
across west Puerto Rico on Sunday. Limited shower and thunderstorm
activity, if any, is expected Monday through at least Thursday.
As a tropical wave moves closer to the forecast area by the end of
the work week, the chance for shower and thunderstorm activity
will increase. Easterly winds will continue to prevail most of the
time with temperatures in the upper 80s to low 90s.

&&

.AVIATION...VFR conditions expected across all terminals for the
next 24 hours. VCSH are still possible through 11/14Z, especially
across TJSJ, TIST and TISX. Then, after 11/17Z, VCSH is possible at
TJMZ and TJPS. Surface winds will be out of the east at 10 KT or
less through 11/13Z, increasing to 15-20KT thereafter from the E to
ENE with sea breeze variations and occasional gusts.

&&

.MARINE...Seas of up to 5 feet and winds of 15 to 20 knots will
continue to prevail across the regional waters through the end of
the work week. There is a moderate risk of rip currents across
some of the local islands. A tropical wave will move into the
area late on Saturday night into Sunday, increasing winds and seas
once again.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 88 80 88 79 / 20 20 20 20
STT 90 79 90 79 / 10 20 20 20
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Re: Caribbean - Central America Weather

#19907 Postby cycloneye » Fri Jul 12, 2019 5:14 am

Area Forecast Discussion
National Weather Service San Juan PR
450 AM AST Fri Jul 12 2019


.SYNOPSIS...

We`ll see several chances for showers during the next week, but
nothing sufficient to break the drought conditions that exist
across the island. Our next best chance for widespread showers
will be Sunday, as our region gets clipped by a tropical wave.
Dust and drier air move in for the first half of the next work
week, though we`ll likely see showers with isolated thunderstorms
develop each afternoon in western Puerto Rico. Another tropical
wave is expected to move in for the end of next week that could
drive greater shower activity.

&&


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

SFC high pressure north northwest of the local islands will continue
to promote an easterly wind flow today into Saturday. Weak upper
level low over the local islands may cause some upper level
instability and divergence aloft, providing some support for
thunderstorm development across western Puerto Rico this afternoon
as it combines with the local effects. The upper low will continue
to move west and more subsidence is expected on Saturday afternoon.
The latest model runs have the tropical wave moving south of the
local area late Saturday into Sunday, but the northern periphery of
the wave could bring good moisture to the local area overnight
Saturday into Sunday, with that the shower activity is expected to
increase across the local area. The temperatures will be near normal
for the next few days across the local islands.

All this means that today through Saturday afternoon, the main cause
of rainfall over the local islands would be locally induced showers
during the daytime hours, especially across western PR in the
afternoon hours, while the rest of the area will have brief isolated
to scattered showers. Then the tropical wave late Saturday into
Sunday will bring shower activity to the local area, which the GFS
model indicates could affect the local waters, USVI, and the eastern
third of PR. The tropical wave and its associated moisture is
expected to have moved away by Sunday afternoon, causing drier air
to move in behind it, leaving only some shower activity across
western and northwestern PR for the afternoon on Sunday.


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

A drier airmass moves in for Monday as a tropical wave passes to our
south. However, showers are still likely in western Puerto Rico in
the afternoon hours as lingering moisture interacts with surface
heating and subsequent convergent wind flows. Saharan dust
returns as well for Monday and will remain for a few days
thereafter. Precipitable water values will continue their downward
trend for Tuesday, with smaller shower chances in the same
locations. Thereafter, an increasing trend in showers will begin
on Wednesday and continue into the weekend.

The leading edge of a tropical wave will arrive on Friday morning,
resulting in scattered showers for eastern Puerto Rico and nearby
islands to the east. These showers will spread westward through the
island throughout the day, and likely result in showers and
thunderstorms for western Puerto Rico by the afternoon hours.
Forecast models suggest a weak upper level trough could be present
to our west that could enhance shower activity. Lingering
moisture will drive isolated showers for Saturday, following a
similar patter as earlier in the week, with morning showers
possible for eastern Puerto Rico and afternoon showers for the
west side.

&&


.AVIATION...

VFR conditions expected across all terminals through
12/17Z. VCSH expected possible through 12/14Z, especially across
TJSJ, TIST and TISX. Then, after 12/17Z, VCTS is expected at TJMZ
and possible TJPS. Surface winds will be from the east at 10 KT or
less through 12/13Z, increasing to 15-20KT thereafter with sea
breeze variations and occasional gusts.

&&


.MARINE...

For the next few days, seas up to 5 feet are expected,
with winds between 15 and 20 knots across the regional waters. Small
craft operators should exercise caution given these fresh trade
winds. A moderate risk of rip currents is expected for most
regional beaches through the weekend.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 88 79 89 79 / 30 20 20 30
STT 89 79 90 79 / 20 20 30 50
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Re: Caribbean - Central America Weather

#19908 Postby cycloneye » Sat Jul 13, 2019 7:44 am

Area Forecast Discussion...CORRECTED
National Weather Service San Juan PR
720 AM AST Sat Jul 13 2019

.SYNOPSIS...A tropical wave will pass south of the local islands
tonight, bringing moisture and shower activity to the local area.
A weak upper low west of the local islands may help promote
thunderstorm development associated with the tropical wave. Dry
air with Saharan dust will be returning on Sunday. Mainly locally
induced showers and thunderstorms are expected in the first part
of the upcoming workweek. Another tropical wave is to move in on
Thursday, which will also be supported by a weak upper low west
of the local islands, so shower activity may increase once again
late next week.

&&

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

A tropical wave has slowly worked its way into the Southern
Caribbean waters. The moisture associated with the wave
will slowly move to the northwest today through early Sunday
morning. The bulk of the moisture is forecast to move across
Puerto Rico Sunday morning and through the afternoon. The GFS-700
to 500 mb and the 250 mb relative humidity chart show relative
humidity values ranging from 20 to 30 percent across Puerto Rico
and the adjacent Island through late Saturday night. However, the
1000 to 850 mb RH values are near 70 to 80 percent.

This means moisture is confined to the surface, and a drier air mass
is still holding in the mid to upper-levels of the atmosphere.
Therefore, for today expect shallow convection in the form of
isolated to scattered showers across the eastern areas of Puerto
Rico during the afternoon. Then showers and isolated thunderstorms
are expected to develop over portions of the interior and western
areas of Puerto Rico later this afternoon.

Sunday, as moisture from the tropical wave pools across Puerto
Rico, shallow convection is forecast to develop early in the
morning and deepen through the afternoon. The drier air in the
mid to upper-levels of the atmosphere is forecast to moisten, and
allow deep convection to briefly develop on Sunday in the form of
moderate to heavy rainfall with isolated thunderstorms. The
moderate to heavy rainfall could cause urban and small stream
flooding in some areas.

Monday, the moisture is forecast to move east of the
region, while a drier air mass works into the east. This will limit
shower development across the region through the beginning of the
workweek. Also, accompanying the drier air mass is Saharan dust,
which will cause hazy skies through early next week. Otherwise,
isolated to scattered showers are possible during the afternoon
due to local and diurnal effects.

.LONG TERM...Tuesday through Sunday...

Dry air with Saharan dust is expected on Tuesday and Wednesday,
but locally induced showers in the afternoon could occur across
western PR. The better chance of shower activity comes on Thursday
and Friday as another tropical wave moves in and increases the
available moisture. In addition, an upper low to the west of the
local islands could provide some support for prolonged shower or
thunderstorm development across the general area late in the
workweek. Thereafter, the moisture decreases and any shower
activity would be locally induced in the afternoons across western
PR, while the rest of the area could observe isolated to
scattered showers.

&&

.AVIATION...Mostly VFR conditions with a few passing SHRA are
forecast to prevail through 13/15Z. Then SHRA/TSRA are expected to
develop across terminals TJMZ and TJBQ until 14/01Z. Moisture
will increase across all terminals by 14/06Z with VCSH/SHRA
across the eastern terminals. Winds will be out of the east to
southeast at 15 to 20 kts with higher gusts, with sea breeze
variations and occasional gusts.

&&

.MARINE...Small craft should exercise caution as winds will be up
to 20 knots across portions of the local waters. Seas will be
generally 3 to 5 feet today, increasing to 6 feet on Sunday, and
perhaps up to 7 feet on Monday in the Caribbean. There is a
moderate risk of rip currents across most of the beaches of Puerto
Rico and Saint Croix today. The northern USVI will have a lower
risk of rip currents.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 89 78 89 79 / 20 40 40 20
STT 88 79 89 80 / 30 30 20 20
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Re: Caribbean - Central America Weather

#19909 Postby cycloneye » Sun Jul 14, 2019 4:56 am

Area Forecast Discussion
National Weather Service San Juan PR
456 AM AST Sun Jul 14 2019

.SYNOPSIS...A tropical is passing south of the local islands,
causing an increase in shower activity over the Caribbean waters
and increasing moisture to the local area today. A weak upper low
west of the local islands is still forecast to help promote
thunderstorm development today when it combines with the tropical
wave. Dry air with Saharan dust will be returning by this evening.
Locally induced showers and thunderstorms are expected in the
first part of the upcoming workweek. Another tropical wave is
still expected to move in on Thursday into Friday, which will
bring deep moisture and will also be supported by a weak upper low
west of the local islands, so shower activity may increase once
again late in the workweek.

&&

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

CIMSS Total Precipitable Water MIMIC products shows a plethora of
moisture rapidly moving through the Caribbean waters. The Moisture
is associated with a tropical wave in the southern Caribbean, which
will continue to pool northwest across portions of eastern and
southern areas of Puerto Rico and adjacent islands. As a result
periods of moderate to heavy rainfall is progged now through late
morning. Also, their is a possibility for isolated thunderstorms
across the aformentioned areas too. This shower activity is forecast
to spread west this afternoon, and move over portions of the
interior and western areas of Puerto Rico. The moisture combined
with local and diurnal effects will yield scattered to widespread
showers and isolated thunderstorms. The moderate to heavy rainfall
could cause urban and small stream flooding, as well as, ponding of
water on the roadways today.

Then later tonight the tropical wave and its associated moisture
will exit the area. Behind the wave is a dry Saharan air mass, which
will filter in from the east. The dry Saharan air will drop
precipitable water value from 2.0 to 1.5 inches over the next
several days.

Therefore, fair weather with hazy skies is progged during the
beginning of the work week with the chance for isolated to scattered
showers during the afternoon as a result of local and diurnal
effects. If showers do develop they will be short-lived due to drier
air in the mid to upper-levels of the atmosphere. Winds will be out
of the east at 15 to 20 mph with higher gusts possible.

.LONG TERM...Tuesday through Monday...

Latest guidance still suggests that dry air with Saharan dust is
to be expected on Tuesday and Wednesday, but locally induced
showers in the afternoon could occur across western PR, while
isolated showers could be observed elsewhere. Shower activity may
increase once again on Thursday and Friday as another tropical
wave moves in and increases the available moisture. However, the
latest long term guidance does not show significant upper level
support, but it does not show subsidence either, so the moisture
will combine with diurnal heating and local effects to cause more
significant shower or thunderstorm development across portions of
Puerto Rico, even though the tropical wave would bring shower
activity to the general area. For next weekend, the moisture
decreases and any shower activity would be locally induced in the
afternoons across western PR, while the rest of the area could
observe isolated to scattered showers.

&&

.AVIATION...SHRA/TSRA will affected terminals the eastern PR and
U.S. VI termimals through 14/15Z. Then SHRA/TSRA will move across PR
western terminals TJBQ and TJMZ, this activity is forecast to
persist through 14/22Z. SHRA/VCTS could cause brief MVRF Cigs across
terminal sites today. Then clearing should commence across the
western terminals with sct to ovc clouds remaining around 030kft to
04kft. Winds out of the east to southeast at 15 to 20 kts with
higher gusts.


&&

.MARINE...Small craft operators should exercise caution due to
seas up to 20 knots and choppy seas increasing up to 6 feet. There
is a moderate risk of rip currents across most of the local
beaches of Puerto Rico and Saint Croix.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 88 78 90 80 / 50 20 30 30
STT 89 80 91 80 / 40 20 20 20
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Re: Caribbean - Central America Weather

#19910 Postby cycloneye » Mon Jul 15, 2019 5:18 am

Area Forecast Discussion
National Weather Service San Juan PR
451 AM AST Mon Jul 15 2019

.SYNOPSIS...Drier air is moving in with Saharan dust which will
cause hazy skies today. Mid to upper level high pressure will
maintain relatively stable conditions for the next few days, and a
strong surface high pressure across the central Atlantic will
maintain an easterly wind flow. A tropical wave is expected on
Thursday into Friday, causing moisture and shower activity to
increase for the latter part of the workweek.


&&

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

A dry Saharan air mass continues to filter into the region from the
east. The saharan air will dry out the mid to upper-levels of the
atmosphere over the region over the next several days. Additionally,
the GFS-20 Skew-T diagram shows a large inversion from 650 to 300
mb, this is the area where the bulk of the dry air lies.
Furthermore, stable conditions are shown by the GFS-20 model, which
shows increasing 500 mb and 250 mb temperatures.

Therefore, a relatively dry stable weather pattern with haze is
progged to prevail through early Wednesday. Also, during the
afternoons showers may develop as a result of significant surface
heating coupled with local and diurnal effects. At any rate if
showers do develop they will be short-lived, due to the lack of
instability and significant low-level moisture across the region.

Daytime high temperatures will be near the upper 80s to the lower
90s near the coastal regions, and the lower to middle 80s in
higher elevations. Winds will be out of the east to southeast at
15 to 20 mph with higher gusts. Heat indices over the next several
days will be near 102 to 106 degrees in some areas across Puerto
Rico and the U.S. Virgin Islands.

Wednesday, patches of moisture embedded in the easterly will move
across the area, thus increase the likelihood for showers and
possible isolated thunderstorms during the afternoon.

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

Shower and thunderstorm activity may increase once again on
Thursday and Friday as another tropical wave moves in and
increases the available moisture. The moisture increase associated
with this tropical wave is forecast to encompass a larger
coverage area locally than the past few waves we have had
recently. The latest model guidance suggested once again a weak
upper low over the local area and to the west, which normally
suggests enhanced instability, but this time it is really weak,
and the model seems to be flip flopping between having no upper
level feature to enhance instability and having some weak trough
in the area. Therefore it looks like any upper level feature for
Thursday and Friday will be weak if there is any at all. That
said, the moisture will combine with diurnal heating and local
effects to cause more significant shower or thunderstorm
development across portions of Puerto Rico, but also the tropical
wave will bring shower activity to the local area overall,
affecting also the USVI. For next weekend, the moisture decreases
but some will still linger, mainly locally induced showers in the
afternoons across western PR would be expected, while the rest of
the area could observe isolated to scattered showers. Another
tropical wave would reach the local area on Monday into Tuesday
but the increase in moisture with this wave appears to be modest,
as suggested by the GFS model.

&&

.AVIATION...VRF conds will prevail over the next 24 hours.
VCSH/SHRA are possible across terminals TJBQ and TJMZ by 15/15z,
with VCSH/SHRA diminishing by 16/01Z. Saharan dust may cause a
reduction in Vsbys across PR eastern terminals, and the terminals
of the U.S. Virgin Islands this afternoon. Sfc winds will be out
of the east to southeast at 15 to 20 kts with higher gusts
possible.

&&

.MARINE...Choppy seas expected today across the local waters, up
to 6 feet with winds up to 20 knots. However, seas will become
hazardous tonight through early Tuesday afternoon as seas increase
up to 7 feet across the offshore Caribbean waters and Mona
Passage. The marine conditions will improve for the second part of
the workweek. There is a moderate risk of rip currents for most of
the local beaches.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 90 80 89 78 / 20 20 20 30
STT 91 80 90 78 / 20 20 40 40
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Re: Caribbean - Central America Weather

#19911 Postby cycloneye » Tue Jul 16, 2019 4:58 am

Area Forecast Discussion
National Weather Service San Juan PR
455 AM AST Tue Jul 16 2019

.SYNOPSIS...Surface high pressure across the northeastern Atlantic
is still dominating the local wind flow, causing easterly winds
for the next several days. An upper level high pressure may
provide some subsidence today and Wednesday. Drier than normal
air mass with some Saharan dust will continue through Wednesday,
then a tropical wave will move in on Thursday into Friday,
increasing moisture and shower activity. Then a more dense
concentration of Saharan dust may return in the weekend, limiting
shower activity.

&&

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

A strong surface high pressure extending across the north central
Atlantic will maintain a moderate to locally fresh easterly wind
flow across the region. Although a mass of relatively drier air
accompanied by a layer of Saharan dust will continue to filter into
from the east today into Wednesday, patches of low-level moisture
are expected to move in from time to time. During the overnight and
morning hours, these patches will result in showers streaming across
the waters into portions of eastern Puerto Rico and the US Virgin
Islands. As the day progresses, the focus of the activity will shift
to portions of the interior and western Puerto Rico. Streamer-like
showers affecting eastern Puerto Rico and the San Juan Metropolitan
area are possible each afternoon. The combination of limited
moisture content and lack of upper level dynamic support will limit
the development of thunderstorms today. However, a gradual erosion
of the mid-to-upper level ridge pattern and trade wind cap--due to a
retrogressive TUTT low moving across the region--will lead to deeper
instability and increased moisture content on Wednesday. So far,
model estimated PW values increase from 1.20 inches this afternoon
to 1.95 inches on Wednesday afternoon. Due to increased instability
aloft and moisture content, an increase in thunderstorm activity is
expected on Wednesday. This may lead to ponding of water on roadways
and poorly drained areas, as well as localized urban and small
stream flooding with the strongest activity.

A moist weather pattern is expected on Thursday as a tropical wave
moving across the Caribbean supports moisture advection into the
forecast area. Model-estimated PW values are expected to remain
between 1.60-1.90 inches throughout the day. Given the somewhat
expected favorable upper level conditions and high moisture content,
there is a better chance for more widespread convection to develop
over the forecast area. As a result, there will be a higher
potential for urban and small stream flooding.

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

Shower and thunderstorm activity may increase once again on
Friday as a tropical wave is expected to have moved in and
increased the available moisture. The moisture increase
associated with this tropical wave is forecast to encompass most
of the local area. The latest model guidance does not show any
upper air support for enhanced convection on Friday. That said,
the moisture will combine with diurnal heating and local effects
to cause more significant shower or thunderstorm development
across portions of Puerto Rico, but also the tropical wave will
bring shower activity to the local area overall, affecting also
the USVI. For next weekend, the moisture decreases but some will
still linger. That said, the latest guidance suggests that the
Saharan dust will make a return, likely limiting the shower
activity across most of the local area except western PR due to
locally induced showers. Another tropical wave would reach the
local area on Monday into Tuesday but the increase in moisture
with this wave appears to be modest, as much of the moisture
appears to remain south of the local area.

&&

.AVIATION...Mainly VFR conditions expected during the next 24 hours.
However, brief MVFR conditions possible at TJMZ due to VCTS expected
between 16/16-23Z. Light and variable winds through 16/14Z,
increasing to 15-20 knots with gusts up to 28 knots and turning from
the east with sea breeze variations. Higher winds expected at TJSJ,
TJPS, TJBQ, TIST and TISX between 16/14-23Z at FL010-030.


&&

.MARINE...Small craft operators should exercise caution as winds
will be up to 20 knots and seas up to 6 feet. There is a moderate
risk of rip currents across most of the local beaches today.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 89 79 88 78 / 20 40 20 20
STT 90 78 89 79 / 20 40 20 20
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Re: Caribbean - Central America Weather

#19912 Postby cycloneye » Wed Jul 17, 2019 4:55 am

Area Forecast Discussion
National Weather Service San Juan PR
420 AM AST Wed Jul 17 2019

SYNOPSIS...A strong surface high pressure extending across the
north central Atlantic will continue to dominate the local region
today and early Thursday. A tropical wave is forecast to move
across the local forecast area between Thursday and Friday.
Another tropical is expected to move across the Caribbean waters
between Monday and Tuesday.

SHORT TERM...Today through Friday...

A strong surface high pressure extending across the north central
Atlantic will maintain a moderate to locally fresh easterly wind
flow across the region. Under this flow, patches of low level
moisture will enhance shower activity across the region. This
activity will focus over the waters and coastal areas during the
overnight and morning hours. Although a slight erosion of the
available moisture is expected by late morning into the early
afternoon hours, diurnal heating and local effects will still
support the development of showers and isolated thunderstorms during
the afternoon hours, particularly along the interior and over
portions of western Puerto Rico. Streamer-like showers affecting
eastern Puerto Rico and the San Juan Metropolitan area from El
Yunque and the local islands cannot be ruled out. However, lack of
upper level support, limited moisture content,and a strong steering
flow will limit the effects this activity may have over these areas.

A slight increase in shower and thunderstorm activity is expected on
Thursday into Friday as the next tropical wave move across the
Caribbean and supports moisture advection into the forecast area.
Model-estimated PW values are expected to hold around 1.60 to 2.00
inches by Thursday afternoon and continuing on Friday. Given the
somewhat expected favorable upper level conditions and high moisture
content, there is a better chance for more widespread convection to
develop over the forecast area. As a result, there will be a higher
potential for urban and small stream flooding.

LONG TERM...Saturday through Thursday...

Lingering moisture will combine with diurnal heating and local
effects to cause more shower or thunderstorm development across
interior and western portions portions of Puerto Rico on
Saturday. A drier airmass and Saharan dust will prevail over the
local region from Saturday night through Monday. On Monday another
tropical wave would reach the local area but the increase in
moisture with this wave appears to be modest, as much of the
moisture appears to remain south of the local area.

AVIATION...SHRA affecting USVI and northern PR terminals will
result in brief MVFR conditions through 17/08Z. Thereafter, mainly
VFR conditions expected. VCSH expected at Leeward and USVI terminals
throughout the day. Afternoon convection will bring VCTS/VCSH to
TJMZ/TJPS between 17/15-23Z. This could result in brief MVFR
conditions. Light and variable winds through 17/14Z, increasing to
15-20 knots with gusts up to 28 knots and turning from the east with
sea breeze variations.

MARINE...Passing showers will continue to move across the local
waters through mid morning. These showers could generate wind gust
of between 20 to 25 knots. Mariners should expect winds in the
range of between 10 to 15 knots. Stronger winds could be
experience near the coast due to sea breeze enhancement,
therefore small craft operators should exercise caution along the
northern and southern coast of Puerto Rico.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 89 78 89 79 / 40 20 20 40
STT 89 79 89 79 / 20 20 20 40
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Re: Caribbean - Central America Weather

#19913 Postby cycloneye » Thu Jul 18, 2019 4:53 am

Area Forecast Discussion
National Weather Service San Juan PR
528 AM AST Thu Jul 18 2019

.SYNOPSIS...A strong surface high pressure extending across the Atlantic
will maintain a moderate to locally fresh easterly wind flow
across the region. A series of tropical waves are expected to
approach the forecast area every 3 to 4 days. The first is
forecast to affect the local islands on Thursday into Friday,
increasing moisture advection and the potential for shower and
thunderstorm activity. Although relatively drier air accompanied
by suspended Saharan dust will filter the area in the wake of each
wave, patches of low-level moisture will support locally induced
activity.


&&

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

High pressure at the surface will persist in the east central
Atlantic and extend across to Florida well beyond the end of the
period. A tropical wave will move into the area today and showers
and thunderstorms associated with the wave will continue through
Friday. An upper level ridge will persist over or around the area
through Friday night. A TUTT low will approach from the northeast on
Saturday.

The total precipitable water product from GOES-17 shows the axis of
the moisture from the tropical wave over Guadeloupe and linear
extrapolation will bring the leading edge over the U.S. Virgin
Islands this evening around 18/22Z and eastern Puerto Rico during
the first half of the night. The GFS did not show the general shape
of the wave well and confidence in its solution is low. There is a
band of moisture over us now that did supply some showers to the
area over night with one half to one inch in some higher elevations
of eastern Puerto Rico with slight drying following during the day
today. Moisture begins dropping off significantly after Saturday and
with it the chances for significant rainfall. But there is patchy
moisture even on Saturday that will allow some showers to develop.
Also extremely low relative humidities during the period appear to
be limited to above 16 kft and does not extend above 30 kft which is
an improvement over last week.

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

A mass of relatively drier air will dominate the local weather
conditions on Sunday into Monday. However, trade wind
perturbations will increase moisture content and the potential
for locally induced shower activity. A series of tropical waves
are expected to approach the region next week. The first is
expected late Monday night into Tuesday, while the second is
expected to arrive on Thursday into Friday. Although model
guidance suggest that the bulk of both waves will remain over
Caribbean waters, an increase in moisture advection from these
features will support the development of shower activity across
most of the forecast area. Lack of upper level support may limit
the development of thunderstorms during the first part of the
week, but a TUTT pattern aloft and a weakening of the trade wind
cap may support enhanced thunderstorm activity by latter part of
the workweek.


&&

.AVIATION...Convection from a tropical wave was movg thru Guadeloupe
as of 18/09Z and will cont thru the USVI by 18/22Z and ern PR btwn
19/00-03Z with SHRA and isol TSRA. Additionally lcl effects will generate
SHRA/TSRA in PR WNW of El Yunque and in NW PR and ovr the central
mtns by 18/17Z with MVFR conds psbl at TJBQ and TJMZ. E-ESE sfc
winds ti increase to 10-20 kt aft 18/14Z with gusts of 24-28 kt alg
coastal locations. Maximum winds ESE arnd 20 kt btwn FL065-100.
Winds VRB less than 10 kt btwn FL200-340 and btwn FL445-510.


&&

.MARINE...Mainly tranquil marine conditions with seas up to 5 feet
and east winds up to 15 knots are expected to hold across the
local waters during the next few days. However, small craft
operators are urged to exercise caution due to localized higher
winds up to 20 knots across the Caribbean waters and coastal
waters of northern Puerto Rico. A moderate risk of rip currents
continues for a few beaches along the north, southeast and south
coast of Puerto Rico, as well as for a few beaches of Culebra,
Vieques and Saint Croix.

&&

.FIRES...Recent KBDI observations continue to support a critical drying
pattern across the southern coastal plains of Puerto Rico with a
value of 717 and 757 reported at Cabo Rojo and Camp Santiago,
respectively. Today`s forecast calls for relative humidity to drop
into the low 40s and low 50s and winds to peak at 15-20 mph with
higher gusts and sea breeze variations, particularly by late
morning into the early afternoon hours. Wetting rains are not
expected since a relatively drier air mass will dominate the
local weather conditions during this period. That said, the
combination of these conditions will result in elevated fire
weather conditions across these areas.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 89 79 89 79 / 20 40 40 30
STT 89 79 89 80 / 20 40 40 40
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Re: Caribbean - Central America Weather

#19914 Postby cycloneye » Fri Jul 19, 2019 4:53 am

Area Forecast Discussion
National Weather Service San Juan PR
537 AM AST Fri Jul 19 2019

.SYNOPSIS...A moderate to locally fresh easterly wind flow will
hold across the region during the next few days. A series of
tropical waves are expected to approach the forecast area during
the next seven days, increasing moisture advection and the
potential for shower and thunderstorms activity. The first
tropical wave will affect the region through late tonight, while
the rest are forecast to approach the forecast area next week.
Although relatively drier air accompanied by suspended Saharan
dust will filter the area in the wake of each wave, patches of
low-level moisture will support locally induced activity.


&&

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

High pressure at the surface will persist in the east central
Atlantic and extend across to Florida well beyond the end of the
period. Moisture behind a tropical wave is now south and east of the
area and will move past the area by noon Saturday. Shower and
thunderstorms will increase. A TUTT low will approach from the
northeast on Saturday and pass 200 miles north of Saint Thomas
Sunday night, but winds at upper levels are generally less than 20
knots during the period.

The total precipitable water product from GOES-17 shows the axis of
the moisture from the tropical wave well tilted and as of 19/09Z
extended from 15 north 68 west to 19 north 60 west and about 180
miles southeast of Saint Croix. This moisture is expected to hang
somewhat before pushing through the area late tonight (20/09Z). The
GFS has been wavering on peak PW values between 1.9 and 2.0 inches.
Drier air is expected to move through Saturday night. Patchy
moisture will bring some showers to eastern Puerto Rico each night
and there is sufficient moisture and instability for showers and
isolated thunderstorms each afternoon--though mainly in western
Puerto Rico. These conditions will bring little change to the
overall weather pattern for the next few days.

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

A few patches of low-level moisture will affect the region
through midday on Monday ahead of the first tropical wave expected
to approach the region next week. In the wake of this wave,
relatively drier air accompanied by suspended Saharan dust will
move in from the east and dominate the region through late
Wednesday night. However, a few trade wind perturbations will
enhance moisture content and the potential for locally induced
afternoon convection each day. Late Wednesday night and
continuing through early Friday, a second wave and associated
plume of moisture is expected to cross the region. Although model
guidance suggest that the bulk of the aforementioned tropical
waves will remain over the Caribbean waters, an increase in
moisture advection, instability and the potential for widespread
showers and thunderstorms can be expected with both waves.
Although weather conditions are expected to improve by Friday
into the weekend, locally induced showers and thunderstorms are
possible each afternoon.


&&

.AVIATION...Brief MVFR in SHRA psbl in Leeward Islands as mstr from
trop wave moves thru. Clrg should begin aft 19/21Z when drier air
moves in. Isold SHRA for USVI and VFR conds expected to prevail. In
PR mstr to incrs durg pd. Areas of SHRA/TSRA to form in NW third of
PR aft 19/16Z with mtn obscurations and will bring pds of MVFR and
brief IFR til arnd 19/22Z including TJMZ/TJBQ. VFR to prevail at
TJPS and TJSJ. Sfc winds E-ESE with sea breeze aft 19/14Z with
gusts to 26 kt psbl. Maximum winds less than 20 kt blo FL540.
Winds less than 10 kt btwn FL125-510.


&&

.MARINE...Tranquil marine conditions with seas up to 5 feet and
east winds up to 15 knots are expected to hold across most of the
local waters during the next few days. However, small craft
operators are urged to exercise caution due to localized higher
winds up to 20 knots across the Mona Passage today. A moderate
risk of rip currents continues for a most beaches along the
north coast of Puerto Rico, as well as a few beaches along the
south and southeast coast of Puerto Rico, south coast of Vieques,
east coast of Culebra, and north coast of Saint Croix.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 89 78 90 79 / 50 30 30 40
STT 89 79 89 79 / 50 50 50 40
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Re: Caribbean - Central America Weather

#19915 Postby cycloneye » Sat Jul 20, 2019 5:12 am

Area Forecast Discussion
National Weather Service San Juan PR
521 AM AST Sat Jul 20 2019

.SYNOPSIS...Although pockets of relatively drier air will filter
the region, lingering moisture from a departing tropical wave and
patches of low-level moisture will support locally induced shower
and thunderstorm activity today through Monday. The next tropical
wave is expected to arrive late Monday night into Tuesday,
increasing the potential for widespread shower and thunderstorms
activity. Weather conditions should somewhat improve by midweek,
but the potential for widespread showers and thunderstorms is
expected once again by the latter part of the week into the
weekend with the arrival of another tropical wave.


&&

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

High pressure at the surface will persist in the east central
Atlantic and extend across to Florida well beyond the end of the
period. The axis of the best moisture is now east northeast/west
southwest across the forecast area. This moisture will diminish
overnight tonight, but patchy moisture will move through the area
Sunday and Monday, so that showers and thunderstorms will continue
to be scattered in the usual diurnal pattern. A TUTT low will move
into place just northeast of Guadeloupe this afternoon with another
lobe of the TUTT north of there passing 200 miles north of Saint
Thomas early Monday morning, but winds at upper levels are generally
less than 20 knots during the period.

Currently the GFS is showing peak precipitable water close to 2
inches at 20/21Z today dropping to a minimum overnight of arnd 1.4
inches. But moisture rebounds rapidly and in time for max heating on
Sunday. Although moisture diminishes somewhat between Sunday and
Monday, it is still sufficient to bring another round of showers and
thunderstorms to Puerto Rico, with some shower in the U.S. Virgin
Islands on Monday.

The GFS shows good vertical velocities over the area today during
the afternoon and even some improvement of the relative humidity
values between 400-500 mb today. This will enhance convective
activity today despite the fact that 500 mb temperatures are only
minimally conducive to thunderstorms at minus 6.5 degrees Celsius.
This should lead to maximum values of rainfall in western and
interior Puerto Rico reaching 2 to 3 inches. Relative humidities at
the 400-500 mb level diminish Sunday and Monday and shower and
thunderstorm activity is expected to decrease somewhat in coverage
and intensity then. Saharan dust will increase later today and
continue for about 36 hours. At this time visibilities are expected
to range from 8 to 15 miles during the period.

.LONG TERM...Tuesday through Sunday...

Model guidance continues to suggest that a wetter pattern will
prevail through most of the long-term forecast period with a series
of tropical waves and trade wind perturbations moving across the
region. As a result, these features will increase moisture
content and the potential for widespread shower and thunderstorms
activity. The first wave and associated plume of moisture is
expected to affect the area on Tuesday, while the second tropical
wave is expected to arrive by Wednesday night and affect the area
through at least late Thursday night. The latter will be quickly
followed by an extended trade wind perturbation that will advect
tropical moisture over the area late Friday into Saturday.
Favorable upper-level conditions expected by the latter part of
the week into the weekend as a TUTT aloft approaches the region
from the northeast and mid-level temperatures drop below -8C will
enhance the thunderstorm activity across the region. Relatively
drier air accompanied by suspended Saharan dust will briefly move
in from the east in the wake of each wave, but lingering moisture
supported by diurnal heating and local effects will enhance the
potential for locally induced afternoon convection each day.


&&

.AVIATION...Drier air spreads into the Leeward Islands by 20/12Z,
but VCSH return--at least to TNCM--arnd 21/00Z. Mstr from a trop
wave conts to move thru the USVI and PR with clrg srpdg thru the
USVI arnd 20/21Z and ern PR by 21/03Z. Saharan dust will reduce
vsbys to 8-15 miles with the clrg. SHRA/TSRA to incrs across PR aft
20/14Z and sprd west to the west coast by 20/18Z. Areas of MVFR/IFR
and mtn obscurations by as early as 20/15Z. VFR is expected to
prevail aft 20/22Z. Winds easterly 10-15 kt aft 20/14Z with sea
breezes. Max winds blo FL540 less than 18 kt. Winds ESE up to FL120
and mostly NNW-N blo FL540.


&&

.MARINE...Tranquil marine conditions with seas up to 5 feet and
east winds up to 15 knots are expected today across the regional
waters. This conditions should prevail through at least Monday. A
low risk of rip currents will continue for all local beaches but
Cramer Park beach in Saint Croix.


&&

.FIRE...Although lingering moisture from a departing tropical
wave is expected to affect the local islands today, pockets of
relatively drier will begin to infiltrate the region from time-to-
time. This will result in relative humidity values to briefly drop
into the low 40s to low 50s across the southern coastal plains of
Puerto Rico. Surface winds will peak at 10-15 mph with higher
gusts, but the effects of the sea breeze may briefly generate
winds up to 20 mph by the early afternoon hours. Given that KBDI
values continue above critical thresholds between 720-760,
elevated fire weather conditions can be expected today. In support
of these conditions, a Fire Danger Statement has been issued.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 90 79 88 79 / 30 20 30 30
STT 89 79 89 79 / 10 60 40 40
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Re: Caribbean - Central America Weather

#19916 Postby cycloneye » Sun Jul 21, 2019 5:10 am

Area Forecast Discussion
National Weather Service San Juan PR
520 AM AST Sun Jul 21 2019

.SYNOPSIS...Surface high pressure across the Atlantic will
continue to promote easterly winds across the local area for the
next several days. Patches of low-level moisture will enhance
localized showers and isolated thunderstorms through early Monday,
before moisture associated to a tropical wave increases the
potential for widespread showers and thunderstorms on Tuesday.
Weather conditions should somewhat improve by midweek with the
entrance of relatively drier air accompanied by Saharan Dust.
However, there is a potential for widespread showers and
thunderstorms by the latter part of the week and early next week
with the arrival of two independent tropical waves, respectively.


&&

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

High pressure at the surface will persist in the east central
Atlantic and extend across to Florida well beyond the end of the
period. Another tropical wave will move through the area early
Monday although the best moisture in the southeast flow behind it
will not arrive until Monday night. This moisture is expected to
clear out rapidly Tuesday afternoon and the moisture that follows
will be mainly south of the area. The TUTT low northeast of the area
this morning will drift to about 400 miles north of San Juan by
Monday morning and continue moving west to north of Hispaniola on
Tuesday. The GFS is showing excellent divergence at 200 mb this
afternoon over western Puerto Rico and good divergence on Monday
afternoon in the same area. Lately these areas of strong divergence
have been well correlated with heavy rainfall amounts and
thunderstorms with frequent lightning. Another area of strong
divergence is forecast to move over eastern Puerto Rico late Monday
night and will coincide with an area of better moisture.
Thunderstorms are not in the forecast at this time but cannot be
completely ruled out even though the last several days have not had
thunderstorm activity over or near the area islands.

The GFS shows moisture declining through around noon today, then
rising slowly through Monday evening. Better moisture arrives
rapidly and a maximum precipitable water value of 2.0-2.1 inches is
expected during the day Tuesday. Although afternoon thunderstorms
with heavy rains and local amounts of 1 to 3 inches are expected
each day. Tuesday morning should bring some of the best amounts of
the entire week on the eastern coast of Puerto Rico. There, local
amounts in excess of 1 inch appear to be possible.

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

Little to no change to the weather conditions expected during the
long-term forecast, favoring two independent periods of active
weather. This will be the result of a series of tropical waves and
trade wind perturbations moving across the region, that will
increase moisture content and the potential for widespread shower
and thunderstorms activity. The first wave and associated plume of
moisture is expected to affect the area late Wednesday night into
Thursday. This feature will be quickly followed by an extended
trade wind perturbation that will enhance another round of showers
and thunderstorms on Friday. Favorable upper-level conditions
with a TUTT pattern aloft and mid-level temperatures dropping to
or below -8C will enhance thunderstorm activity across the region
by the latter part of the week into the weekend. Another tropical
wave is expected to arrive on Monday, which will generate another
period of active weather. Relatively drier air accompanied by
suspended Saharan dust will briefly move in from the east in the
wake of each wave, but lingering moisture supported by diurnal
heating and local effects will enhance the potential for locally
induced afternoon convection each day.


&&

.AVIATION...Bands of moisture will move through the area during the
next 24 hours bringing sct SHRA and brief MVFR cigs to TNCM/TKPK
during the period. Aft 21/14Z SHRA/TSRA to dvlp ovr PR with areas of
MVFR/IFR and mtn obscurations, TJMZ/TJBQ are the main TAF sites
affected although TJPS and TJSJ will have VCTS. SHRA/TSRA to
diminish aft 21/21Z. Sfc winds E 12-18 kt with sea breezes. Max
winds blo FL525 18 kt or less. Winds ENE-ESE blo FL320.


&&

.MARINE...Mainly tranquil marine conditions with seas up to 5
feet and east winds up to 15 knots are expected today across the
regional waters. However, localized winds up to 20 knots may
require small craft operators to exercise caution across the
coastal waters of northern Puerto Rico. A moderate risk of rip
currents is in effect for beaches along the north central to
northwest coast of Puerto Rico, while a low risk of rip currents
is expected elsewhere.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 88 79 89 80 / 30 40 40 40
STT 89 79 89 80 / 40 40 40 50
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Re: Caribbean - Central America Weather

#19917 Postby cycloneye » Mon Jul 22, 2019 5:11 am

Area Forecast Discussion
National Weather Service San Juan PR
527 AM AST Mon Jul 22 2019

.SYNOPSIS...A tropical wave and its associated moisture will move
south of Puerto Rico later this afternoon. The added moisture
combined with local effects will yield showers and thunderstorms
across most of Puerto Rico this afternoon. Later this evening the
wave moves west of the area, however, lingering moisture will
remain through Tuesday. We expect showers and isolated
thunderstorms during the afternoon Tuesday. Then Thursday, a
tropical wave is forecast to move into the area, and increase
showers and isolated thunderstorms. Saharan dust moves into the
area on Friday and will be heavier on Saturday.

&&

.SHORT TERM...High pressure at the surface will persist in the
east central Atlantic and extend across to Florida and Georgia
during the period. High pressure will shift to the central
Atlantic by Wednesday. Another tropical wave will move through the
area today although the best moisture in the southeast flow
behind it will not arrive until tonight. Currently it looks like
it could arrive in Saint Croix as early as 22/21Z and eastern
Puerto Rico near 23/03Z. This moisture is expected to clear out
rapidly Tuesday afternoon.

The TUTT low north of Saint Thomas will drift to about 350 miles
north of San Juan by 22/15Z and continue moving west northwest to
north of Hispaniola on Tuesday. The GFS is showing very good
divergence at 200 mb this afternoon over west central Puerto Rico
and good divergence on Tuesday morning over eastern Puerto Rico at
23/12Z. Lately these areas of strong divergence have been well
correlated with heavy rainfall amounts and thunderstorms with
frequent lightning. Thunderstorms have not been seen over eastern
Puerto Rico in the early morning there is a slight chance Tuesday
morning. Drier air and some Saharan dust will move in on Wednesday,
but there is still a chance for afternoon showers and thunderstorm
in western Puerto Rico due to favorable low-level conditions.

Moisture peaks this afternoon and late Tuesday morning at above 1.8
and 1.9 inches respectively. This is very supportive of continued
active convection during that time span. Moisture then falls off to
a minimum Tuesday afternoon to below 1.2 inches when most convection
will be suppressed.

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

The beginning of the long-term period will be relatively quiet with
several tropical waves moving across Puerto Rico and adjacent
islands. The first tropical wave is progged to push into the
Caribbean waters early Thursday morning and move over the islands
east of Puerto Rico during the afternoon. Then the western areas of
Puerto Rico during the peak of the afternoon. Although the leading
edge of the wave will move west of the area on Thursday evening; the
back edge of the tropical wave will move across Puerto Rico early
Friday. The moisture is expected to lingering through Saturday
before slowing filtering out of the region. The increase in low-
level moisture during the end of the work week coupled with
significant surface heating, and sea breeze convergence will lead to
the development of scattered to isolated thunderstorms during the
afternoon. This activity will mainly develop across the western and
interior areas of Puerto Rico. However, showers and isolated
thunderstorms could develop across the eastern areas of Puerto Rico,
and adjacent islands during the afternoon too.

Additionally, recent guidance shows upper-level conditions becoming
more favorable for widespread showers and isolated thunderstorms on
Friday and Saturday as a result of a TUTT low that is progged to
retrograde across the Puerto Rico. Also, an increase in upper-
level divergence will enhance upper-level instability across
portions of western and interior areas of Puerto Rico. However,
one caveat that could limit the development of widespread showers
and isolated thunderstorms, is the drier air that is expected in
the mid to upper levels of the atmosphere. Additionally,
the drier air will be accompanied by Saharan dust, which will
also limit the vertical development of showers during the
afternoon. Still with the drier air in place 500 mb temperatures
are forecast to range from -8 to -10 Celsius.

Sunday, the bulk of the moisture moves west of Puerto Rico, however,
some moisture is expected to linger across the islands through
early Monday morning. Then a drier air mass will move into the
region from the east, and limit shower activity later on Monday
and into Tuesday.

&&

.AVIATION...Bands of moisture will move through the area during the
next 24 hours bringing sct SHRA and brief MVFR cigs to TNCM/TKPK
during the period. Aft 22/16Z SHRA/TSRA to dvlp ovr PR with areas of
MVFR/IFR and mtn obscurations, TJMZ/TJBQ are the main TAF sites
affected although TJPS and TJSJ may have VCTS. SHRA/TSRA to diminish
aft 22/21Z. Sfc winds ESE 12-18 kt with sea breezes. Max winds SW 30-
40 kt btwn FL335-400.

&&

.MARINE...

Seas will range from 3 to 5 feet across the local and offshore
through Thursday. Winds will be out of the east to southeast at 15
to 20 kts with higher gusts possible. Showers and isolated
thunderstorms are forecast to develop across the local and
offshore waters today, with lightning and heavy rain possible.
Therefore, small craft operators are urged to exercise caution
across the the local and offshore waters this afternoon.

A moderate risk of rip currents for most of the local beaches of
Puerto Rico today except for the western and eastern beaches of
the island. Also, a moderate risk of rip currents for the southern
beaches of Vieques, and the northeast beach of Culebra.
Additionally, a moderate risk of rip currents for the northern
beaches of the U.S. Virgin Islands.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 90 79 91 79 / 50 60 60 30
STT 90 81 92 79 / 40 60 30 30
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Re: Caribbean - Central America Weather

#19918 Postby cycloneye » Wed Jul 24, 2019 5:00 am

Area Forecast Discussion
National Weather Service San Juan PR
441 AM AST Wed Jul 24 2019

.SYNOPSIS...

Drier conditions with hazy skies is forecast to prevail across
the area today. Then a tropical wave and its associated moisture
will push through the region early Thursday and linger into midday
Friday. Another round of Saharan air will push across the region
Friday afternoon and hold through the weekend. Early next week
several robust tropical waves are forecast to move into the
region. The first wave is forecast to move across Puerto Rico and
the adjacent islands on Monday, then another wave late Tuesday
into early Wednesday. The moisture associated with the tropical
waves will cause the development of deep convection in the form of
showers and thunderstorms early next week.

&&

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

Drier air with Saharan dust will continue to result in hazy skies
and limit any afternoon convection over western Puerto Rico today.
Hi res model guidance suggest less than 1.00 inch of rain with the
heaviest showers over west/southwest PR. Max temps should range
between the mid 80s and low 90s across the islands. Breezy trades
will continue between 15-20 mph with higher gusts along coastal
areas. Forecast soundings are indicating below precipitable water
values with PW near 1.25 inches through at least 06Z on Thursday.
Low-level moisture picks up quickly (1.81 inches of PW by 15Z)
with the passage of a tropical wave by Thursday morning. This wave
will bring scattered showers with possible isolated thunderstorms
across the region through the day. Models suggest pockets of
divergence aloft over the islands during the afternoon, this will
support thunderstorm development from streamers off the USVI and
along the mountain ranges of PR. Urban and small stream flooding
can be expected on Thursday afternoon and localized flash flooding
can not be ruled out.

After the wave passage a band of low level moisture trails the wave
and this will bring additional showers during the night across the
USVI and eastern sections of PR. On Friday, a typical seasonal
weather pattern is expected with quick passing showers streaming
from the east across the region and reaching briefly portions of the
islands. This will be followed by diurnally induced afternoon
showers and thunderstorms, mainly over the interior and western
sections of PR. Urban and small stream flooding will be the main
threat.

&&

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

A dry air mass will further strengthen the inversion in the mid-
levels of the atmosphere on Saturday. The strengthening inversion
will limit the coverage of showers and isolated thunderstorms this
weekend. Nevertheless, showers and thunderstorms will develop across
portions of the interior and western areas of Puerto Rico, as a
result of local effects, sea breeze convergence, and significant
surface heating. However, these showers will be short-lived which
will cause light rainfall accumulations. The above conditions are
also expected on Sunday due to the drier air.

Then a robust tropical wave is forecast to move into the Caribbean
waters late Sunday into early Monday. The wave moisture will moisten
the lower-levels of the atmosphere and erode the drier air in the
mid to upper- levels of the atmosphere. Recent guidance shows an
TUTT low positioned near Hispaniola on Monday. The position of the
TUTT low supports an increase in upper-level instability across
Puerto Rico. In addition, a veering wind flow will aid in the
development of showers and thunderstorms.

For this reason deep convection is expected to develop that will
yield widespread showers and thunderstorms, with urban and small
stream flooding. Also can`t rule out the development of single
cell thunderstorms which could produce hail, downbursts, and
heavy rainfall.

Tuesday, a drier air mass pulls across the region and gives us a
reprieve in the development of deep convection. However, another
wave is forecast to push across the region late Tuesday night into
early Wednesday morning. The tropical wave and its associated
moisture will cause the development of deep convection, that will
yield numerous showers and thunderstorms. Then on Thursday a drier
air mass is forecast to move into the region again with isolated to
scattered showers possible during the afternoon.

&&

.AVIATION...

Mainly VFR conditions expected to prevail across all
the terminals. Some HZ due to Saharan dust is expected but
visibility should remain abv 7 SM. SHRA/TSRA may cause tempo MVFR
conditions at TJMZ btw 16z-22z. East winds expected between 15-20
kt with higher gusts and sea breeze variations aft 14z.

&&

.MARINE...

Sea will range from 3 to 6 feet across most of the local and
regional waters. Winds will be out of the east at 15 to 20 kts
with higher gusts today. As a result of the above conditions Small
craft operators are urge to exercise caution across the local
waters. Thursday a tropical wave is forecast to move into the
Caribbean waters, and cause scattered to isolated thunderstorms
across all the local waters. A moderate risk of rip currents will
continue for most local beaches through the end of the week.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 90 79 89 79 / 20 40 40 30
STT 91 79 90 80 / 10 40 40 40
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Re: Caribbean - Central America Weather

#19919 Postby cycloneye » Thu Jul 25, 2019 5:02 am

Area Forecast Discussion
National Weather Service San Juan PR
410 AM AST Thu Jul 25 2019

.SYNOPSIS...

A tropical wave and its associated moisture currently east of Puerto
Rico will arrive across the eastern areas of the island by rush hour
this morning. The moisture associated with the tropical wave will
yield showers and isolated thunderstorms across most areas of the island
this afternoon. Behind the wave is a patch of drier air that will
move across adjacent islands and Puerto Rico later night.
However, on the hills of the drier air is another patch of
moisture that will cause showers and possible isolated
thunderstorms on Friday. Late Friday night a drier air mass will
pour into the region and hold through the weekend with the
possibility for showers and isolated thunderstorms during the
afternoons mainly across portions of the interior and western
areas of Puerto Rico.

The beginning of the work week will be
unsettled as a result of increasing low-level moisture from
several tropical waves that are forecast to flow across the
region. The unsettled weather should clear out of the area by
Wednesday due to a drier air mass moving into the region.

&&

SHORT TERM...Today through Saturday...

A tropical wave is producing scattered to numerous showers and
isolated thunderstorms from the Leeward islands into the Anegada
Passage. This activity is expected to reach just before sunrise the
U.S. Virgin Islands and spread across Puerto Rico through the day.
Daytime heating and sea breeze convergence and the passage of the
wave will enhance thunderstorm development and heavy showers. Gusty
winds and urban and small stream flooding are expected with the
thunderstorms today. Localized flash flooding can not be ruled out.

Winds will increase on Friday and Saturday and a drier air mass with
Saharan dust will bring more stable conditions overall across the
region. However. a plume of moisture trails the wave and this in
combination with daytime heating, sea breeze convergence and other
local effects will result in showers developing once again over the
interior and western sections of PR on Friday afternoon. A
northeasterly steering wind flow on Saturday should shift the focus
of afternoon showers over southwest PR. But, lighter rainfall
amounts are expected. Breezy and hazy skies are expected across the
rest of the area.

&&

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

A drier air mass will be in place on Sunday, the drier air will keep
a relatively strong inversion in the mid to upper-levels of the
atmosphere, and limit the vertical development and coverage of
showers. However, showers and thunderstorms will develop across
portions of the interior and western areas of Puerto Rico, as a
result of local effects combined with sea breeze convergence, and
surface heating. The lack of of mid-level moisture and instability
will keep rainfall accumulations light.

Monday, a healthy tropical wave and its associated moisture will
pour across the far eastern islands during the morning, and continue
across eastern Puerto Rico and points west during the afternoon. The
tropical wave moisture will further moisten the low-levels of the
atmosphere, and erode the drier air in the mid to upper-levels of
the atmosphere too. This will lead to the development of scattered
to numerous showers and thunderstorms across Puerto Rico and
adjacent islands during the afternoon. But, several deterrents that
might prevent the development of numerous showers and thunderstorms
during the afternoon, which are the lack of upper-level forcing and
mid to high level clouds.

Tuesday, the moisture lingers across the area, which will aid in the
development of showers and isolated thunderstorms across Puerto Rico
during the afternoon. The moisture rapidly retreats by Wednesday
afternoon, with a meager patch of drier air filing in behind the
moisture. However, the drier air will be short-lived as another
patch of moisture rapidly fills in across the region by Wednesday
night.

Thursday, a drier air mass moves into the region and holds through
Friday. But, moisture embedded in the easterly trades will move
across the area from time to time. Therefore, showers and isolated
thunderstorms are possible during the afternoon across portions of
the interior and western areas of Puerto Rico. Additionally, during
the morning a few passing showers may develop across portions of
eastern Puerto Rico and adjacent islands.

&&

.AVIATION...

SHRA/TSRA is expected to increase early this morning from
the eastern waters of the islands due to a tropical wave. Tempo MVFR
conditions and mountain obscd will spread across all USVI/PR
terminals through the day. Brief IFR conds are possible at JBQ/JMZ
this afternoon. East winds between 15-20 kt with sea breeze
variations and higher gusts are expected aft 14z.

&&

.MARINE...

Seas up to 6 feet across most of the local and region waters
today as a result of a tropical wave. Winds out of the east to
southeast at 15 to 20 kts. Therefore, Small boat operators should
exercise caution due to seas up to 6 feet and winds 15 to 20
knots. A moderate risk of rip currents will continue for the
northern and southern beaches of Puerto Rico and Saint Croix.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 88 79 90 80 / 40 50 20 20
STT 88 80 89 80 / 60 50 30 30
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Re: Caribbean - Central America Weather

#19920 Postby cycloneye » Fri Jul 26, 2019 4:53 am

Area Forecast Discussion
National Weather Service San Juan PR
503 AM AST Fri Jul 26 2019

.SYNOPSIS...
This morning a patch of moisture caused scattered to isolated
showers to develop across portions of the eastern and interior
areas of Puerto Rico. Some showers produced lightning mainly over
eastern Puerto Rico and the regional waters. The moisture
currently over the area will continue to diminish through the
remainder of the day. Then a drier air mass will filter into the
region from the east and hold over the area through the weekend.
Early next week will be unsettled as a result of several tropical
waves that will transverse the region. The first tropical wave is
expected to arrive on Monday, then another wave is expected late
Tuesday into Wednesday. Therefore, expect scattered to numerous
showers and isolated thunderstorms during the afternoons.

&&

.SHORT TERM...

A drier air mass with suspended Saharan dust will prevail through
the short term period. This will promote mainly fair weather
conditions and hazy skies each day. However, an upper level trough
moving from the east and shallow moisture under the drier air
mass pushed by a surface high across the central Atlantic, will
bring passing showers across the U.S. Virgin Islands and eastern
sections of Puerto Rico during the overnight and early morning
hours. This will be followed by diurnally induced afternoon
convection over the western sections of PR each day. Breezy
conditions are expected each day with sustained winds between
15-20 mph and higher gusts across coastal areas. Max temps are
forecast to range from the high 80s to low 90s.

&&


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

Monday, a healthy tropical wave and its associated moisture is
forecast to push across the far eastern islands during the morning,
and continue across eastern Puerto Rico and points west during the
afternoon. The tropical wave moisture will moisten the low-levels of
the atmosphere, and erode the drier air in the mid to upper-levels
of the atmosphere by the afternoon. The moisture increase will aid
in the development of scattered to numerous showers and
thunderstorms across Puerto Rico and adjacent islands during the
afternoon.

Tuesday, the moisture lingers across the area, which will aid in the
development of showers and isolated thunderstorms across Puerto Rico
during the afternoon. Late Wednesday the moisture is forecast to
move west of Puerto Rico, with drier air holding across the region
through Thursday night. But, moisture embedded in the easterly
trades will move across the area from time to time. Therefore,
showers and isolated thunderstorms are possible during the afternoon
across portions of the interior and western areas of Puerto Rico.

Friday, another tropical and its associated moisture will spread
across the U.S. Virgin Islands during the morning hours, then across
Puerto Rico during the afternoon and evening. The low-level moisture
combined with local and diurnal effects will aid in the development
of numerous showers and thunderstorms. Late Friday night the bulk of
the moisture is expected to be west of Puerto Rico, however, some
lingering moisture is expected across some areas of Puerto Rico.

Saturday, a dry Saharan air mass will trickle into the region and
reduce showers and thunderstorm development during the afternoon
over Puerto Rico and adjacent islands.

&&

.AVIATION...Mainly VFR conditions expected to prevail across all
terminals during the next 24 hours. However, SHRA/TSRA may cause
tempo MVFR conds at JMZ this afternoon. East winds between 15-20 kt
with sea breeze variations and higher gusts are expected aft 14z.


&&

.MARINE...

Seas will range from 3 to 6 feet across the regional waters today.
Winds will be out of the east at 15 to 20 kts with higher gusts
likely. Due to seas up to 6 feet in some areas, and winds up to 20
kts small craft operators are urged to exercise caution. A
moderate risk of rip current for northern, southern and eastern
beaches of Puerto Rico.

&&

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