Caribbean - Central America Weather

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
452 AM AST Fri Jul 15 2022

.SYNOPSIS...

A tropical wave moving out of the region will continue to result
in cloudiness and some passing showers during the morning hours.
As the day progress, a drier airmass with some particles of
Saharan dust will filter into the region. This will limit the
widespread shower activity. Typical weather conditions are
forecast to prevail for the upcoming weekend and early next week.

&&

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

A weak upper high pressure has moved over the local islands, which
will stay over the area through the day. Then a tilted upper trough
will move over the local area on Saturday, persisting into Sunday.
The available moisture will decrease today but moisture will still
be enough to allow locally induced thunderstorms in the afternoon,
especially over western PR, though brief thunderstorms elsewhere in
PR will not be ruled out. For the USVI, isolated to scattered
showers are forecast, some of the showers could be moderate to
heavy, but are also expected to move quickly and therefore are
expected to be generally brief. The hi-res models are suggesting
areas of over an inch of rain across western PR, which, if it
verifies, could cause some urban and small stream flooding. However,
the hi-res models show very little accumulations for the USVI. A
weak tropical wave is expected to move in on Saturday, which will
cause a brief increase in moisture, but there will be some Saharan
dust embedded, which could limit strong convection. Nevertheless,
there is still scattered to locally numerous showers in the
forecast, because there may be some instability enhancement from the
upper low expected.

Drier air returns on Sunday, with some Saharan dust still in the
area. The latest guidance do suggest less shower activity on Sunday,
so only isolated to scattered showers are in the forecast, with the
NW quadrant of PR having scattered showers, while elsewhere in PR
and across the USVI we can expect mostly fair weather.

Temperatures are expected to be near normal, with highs in the upper
80s to low 90s across the lower elevations of PR and the USVI. Heat
index values could reach the low 100s in PR, while the USVI`s heat
index may remain mainly in the mid to upper 90s. Across the highest
elevations of PR, the daytime temps will be in the low to mid 80s.

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

A variable weather pattern is forecast for the first part of the
long term period. On Monday into early Thursday, both model
guidance (GFS and ECMWF)agrees with some unstable conditions at
the upper levels due to the presence of a tilted upper level
trough moving westward into our region. As the upper feature moves
more into the area, the best day for divergence aloft over the
area will be on late Tuesday into Wednesday. At the surface, on
monday into Tuesday, conditions are forecast to stay very drier as
a drier airmass with some particles of saharan Dust filters into
the region and erode all the available moisture. Given the
expected conditions, some limited but heavy shower activity is
forecast each day, especially in the afternoon hours. On
Wednesday, GFS shows an increase in moisture from a tropical wave
moving well at our south. This moisture in combination with the
unstable conditions aloft will result in more widespread shower
activity. Therefore, expect, the passing showers in the evening
and morning hours, and heavy rainfall activity with isolated
thunderstorms in the afternoon hours over the western interior.

More stable conditions are forecast on Thursday into Friday, as a
ridge establishes in the mid level. However, some patches of
moisture embedded in the trade winds reach the local islands.
Given the presence of the patches of moisture and the local
effects will result in the afternoon hours.


&&

.AVIATION...SHRA/TSRA activity expected today across the local flying
area. This will cause VCSH across the local terminals through the
day, possibly brief SHRA at the terminals. After 15/16Z, the
chance for TSRA increases in areas near TJBQ and TJPS, possibly
causing VCTS. Winds will be from the east at around 15 knots with
occasional gusts and sea breeze variations.


&&

.MARINE...

At the surface, a broad high pressure located over the Central
Atlantic will continue to promote moderate to fresh easterly
winds over the local waters. This will result in choppy and
hazardous seas up to 7 feet for all the Atlantic waters were a
small craft advisory is in effect. For the rest of the local
waters seas will remain up to 6 feet, therefore, small craft
operators are urged to exercise caution. There is a high risk of
rip current for all the north exposed beaches of Puerto Rico,
Culebra and St. Croix for the next several days. For the rest of
the exposed beaches, the risk will remain low to moderate.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 89 77 89 78 / 50 40 40 20
STT 88 79 90 79 / 30 30 30 20

[cycloneye]

 https://twitter.com/TTWeatherCenter/status/1548070437845811202

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
521 AM AST Sat Jul 16 2022

.SYNOPSIS...A tropical wave will increase shower and thunderstorm
activity today across the region. A weak Saharan Air Layer (SAL)
will promote hazy skies and drier conditions later this evening
into Sunday. Breezy conditions are expected to prevail through
Monday. Another tropical wave, with better moisture content is
forecast to move across the area by midweek.


&&

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

A broad surface high pressure establishing over the Central Atlantic
will continue to result in breezy conditions across the islands.
As the surface high pressure holds over the Central Atlantic
during the day, a tropical wave will reach the local islands
during the morning hours today. This will increase moisture, and
in combination with the local effects will enhance the potential
for shower activity. In the morning hours, the showers will affect
mostly the windward sections of the islands. Then, in the
afternoon hours, expected the heaviest activity with isolated
thunderstorms over the interior and western sections of Puerto
Rico. Given the expected conditions, ponding of water in roadways
and poor drainage areas, as well minor flooding are expected. For
tonight, conditions are forecast to improve when a much drier
airmass with some Saharan Dust Particles moves into the area.
These conditions will promote more fair weather conditions for
tonight. Additionally, the presence of the SAL will turn more
warmer temperatures in the overnight hours.

From Sunday into Monday, global model guidances, suggest some
unstable conditions aloft as a tilted upper level trough sinks
over the area, with the axis over the Mona Passage. Although
conditions at the upper levels are somewhat favorable for
vertical development of showers, the lack of moisture on Sunday
will promote mostly clear skies with some clouds in the morning
hours, then, the local effects with the available moisture will be
enough for some localized shower activity over the western
sections of PR. On Monday, same conditions at the upper levels
will remain in place, but more frequent showers will be possible
due to an increase in moisture embedded in the trade winds from a
tropical wave moving well to our south. Regardless, shower
activity is not forecast to be long-lived due to the trade wind
cap.

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

An upper-level low is expected to linger just north of the region
on Tuesday and Wednesday, promoting some instability over the
area. At the lower-levels, an area of moisture is expected to
stream quickly on Tuesday over the islands, and this is expected
to be followed by a tropical wave between Wednesday and Thursday.
The precipitable water content (PWAT) is currently expected to
peak around 2.20 inches by late Wednesday night. Therefore, shower
and thunderstorm activity is expected to increase by midweek
across the region. The risk of urban and small stream flooding
will increase across the islands.

A weak mid-to upper-level ridge is forecast to build after the
wave passage, however, PWAT remains at near-normal levels through
the end of the long term period. There is a brief period of drier
air, and warming of the 500 mb temperature from late Friday into
Saturday morning. Before another upper-level low builds just north
of the area, and another tropical wave enters the eastern Caribbean
and streams across the area through on Sunday.


&&

.AVIATION...VFR conds are expected to continue through the forecast
period. The arrival of a tropical wave will result in VCSH for the
eastern sites and TSRA over TJBQ at around 17/18Z. At 17/22Z
conditions will improve and no shra activity is forecast. Winds will
be from the east at around 10 knots until 17/12Z increasing to 15
knots and even higher occasional gusts and sea breeze variations,
becoming at 10-12 knots overnight.


&&

.MARINE...A tropical wave and moderate to fresh trades will promote
hazardous seas and coastal conditions today and through the rest
of the weekend. Isolated thunderstorms are possible across the
local waters through this afternoon. Breezy conditions are
expected across the Atlantic coastal waters, the Mona Passage and
the offshore Caribbean waters. There is a high risk of rip
currents along the north and east coasts of PR, Culebra, and St.
Croix.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 87 78 89 79 / 60 20 20 30
STT 89 80 90 78 / 60 20 20 20

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
447 AM AST Sun Jul 17 2022

.SYNOPSIS...Saharan Air Layer (SAL) and dry air will lead to
mainly fair weather conditions today across the local islands.
Afternoon convection still expected over the western portions of
Puerto Rico. By Wednesday, moisture levels will start to increase
due to the passage of a tropical wave. Choppy marine conditions
will persist across most of the local waters.


&&

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

A weak Saharan Air Layer (SAL) will continue to promote drier air
and hazy skies across the islands today. A strong trade wind cap
will continue to promote breezy conditions across the region, and
inhibit widespread or vertical development of showers through the
day. Latest satellite imagery indicates areas of shallow moisture
content being carried by the fresh to strong trades across the
regional waters. In general, this should cause mainly an increase in
low-level cloudiness with brief passing showers over the islands,
leaving minor rainfall amounts through the morning hours, followed
by limited shower development over portions of western PR during the
afternoon hours.

On Monday, a weak tropical wave is expected to pass well south of
the region, while a patch of moisture embedded in the east to
northeast trades arrives from the Atlantic waters. The SAL is
expected to weaken, therefore, a slight increase in moisture content
is expected compared to today. This scenario will support early
morning and nighttime passing showers between the USVI and
east/northeast PR, and diurnally induced afternoon showers over
western PR. On Tuesday, a surface trough is expected to move from
the east, turning winds more from the east to southeast and further
increasing moisture content across the area. Therefore, expect
showers to increase in areal coverage and develop mainly over the
northwestern quadrant of PR in the afternoon.

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

An upper-level low will continue to linger north of the region until
Wednesday. Associated instability and tropical moisture will result
in showers from time to time. By late Wednesday through Thursday a
strong tropical wave is expected to reach the local area. The
precipitable water content (PWAT) is expected to peak around 2.50
inches, enhancing the shower activity and thunderstorm potential
across the islands. Therefore, the risk for urban and small stream
flooding, and hazardous driving conditions will be present during
the passage of this wave. The latest GFS-20 model guidance
suggest a quick movement of this wave, moving away from the local
area by late Thursday night. By Friday through Saturday an upper-
level ridge will take place, improving the conditions aloft and
more drier air will be present. However, a seasonal weather
pattern will be observed with showers during early morning hours
over the east, followed by afternoon convection over the central
and western portions of Puerto Rico. Then, by the end of the
period another tropical wave is expected to approach the islands
and persist through early next week.

&&

.AVIATION...Mainly VFR conditions are expected to prevail across all
terminals during the next 24 hours. However, trade wind showers
could move at times across the USVI and eastern PR terminals. East
winds will increase between 14-22 kts aft 14z, with gusts up to 35
kt and sea breeze variations. HZ due to Saharan dust will continue
today, but VSBY will remain P6SM.

&&

.MARINE...Choppy marine conditions will prevail today. Seas
between 4 to 6 feet are expected with winds up to 20 knots across
most of the local waters. There is a high risk of rip currents in
effect for the north-facing beaches of Puerto Rico and eastern
Saint Croix.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 89 79 90 79 / 40 60 60 50
STT 90 79 90 78 / 40 30 30 40

&&

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
405 AM AST Mon Jul 18 2022

.SYNOPSIS...Low concentration of Saharan dust will continue
across the region, maintaining slight hazy conditions. A weak
perturbation will pass today and bringing patches of moisture to
the local area. Breezy conditions are expected today along the
coastal areas and with passing showers from time to time. Choppy
marine condtions will continue across the local waters for the
next several days.

&&

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

A tropical wave with axis now south of Puerto Rico and the Mona
passage will continue to exit the eastern Caribbean today. A
surface high pressure ridge will be reinforced across the area
today and through the rest of the period to increase the east to
northeast winds. A weak easterly perturbation and patch of low
level moisture is expected to cross the region later today into
Tuesday. A mid to upper level trough (TUTT) and associated area of
low pressure will linger north of the region, while a high
pressure ridge will extend across the northeast Caribbean through
the period. A low concentration Saharan dust will continue across
the region through most of the period to maintain slightly hazy
conditions. Somewhat breezy conditions are expected during the
daytime especially along the coastal areas and with the passing
showers.

For the rest of the early morning expected passing showers to affect
the windward side and portions of the north coastal areas of the
islands. Afternoon convection will be focused mainly over portions
of the central interior and west sections of Puerto Rico. Lesser
activity is expected in and around the U.S. Virgin Islands, which
should be mainly on the west-end or downwind of the islands in the
form of streamers. A few late afternoon showers may quickly stream
across portions of the San Juan metro, but no significant
accumulations are so far expected in these areas.

Tuesday into Wednesday an induced surface trough is forecast to
cross the region bringing another surge of moisture across the area
in the prevailing easterlies. This should also increase periods of
passing showers during the morning hours along the north and east
coastal areas. Afternoon convection should be focused over the east
interior and west central- west sections of Puerto Rico. The
activity should be fast moving, as the low level winds are expected
to increase due to the tightening of the local pressure gradient.
However minor urban and small stream flooding as well as ponding of
water on roads and poor drainage areas will remain possible with the
heavy downpours and afternoon convection.

Somewhat drier with breezy and hazy conditions are forecast for
early Wednesday with more typical passing morning showers followed
by afternoon convection focused over parts of the interior and west
sections of Puerto Rico. A few streamer-like showers may affect the
U.S. Virgin Islands from time to time. However by late Wednesday and
during the overnight hours, expect increasing instability and
tropical moisture transport, as a vigorous tropical wave is still
forecast to approach the region thus increasing the chance for
showers and thunderstorms across the regional waters. By then expect
better potential for urban and small stream flooding across portions
of eastern Puerto Rico and the U.S. Virgin Islands. Stay tuned as
some adjustments may be made as far as the timing of the arrival of
moisture in advance of the wave.

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

A vigorous tropical wave located over the central Atlantic is
forecast to move across the local area for the first half of the
period. Unstable conditions aloft will promote instability
through at least Friday. The precipitable water content (PWAT)
still expected to peak around 2.50 inches during the passage of
the wave. An increase of shower activity and thunderstorms will
start on late Wednesday across the U.S. Virgin Islands and eastern
Puerto Rico. Then, by early Thursday affecting the rest of Puerto
Rico. The latest GFS-20 model guidance continues to suggest a
quick movement of this wave, moving away from the local area by
late Thursday night and early Friday. Nonetheless, the risk for
urban and small stream flooding, and hazardous driving conditions
will be present. By mid Friday onwards, and mid to upper-level
ridge will establish over the local area. Drier air and Saharan
Air Layer (SAL) will prevail for the rest of the period, with
limited rainfall activity across the U.S. Virgin Islands and
Puerto Rico. Although, some streamers could form. Expect warmer
temperatures and hazy skies.

&&

.AVIATION...Prevailing VFR conds at all local terminals durg prd
with no obstructions to flt vis attm. Quick passing trade wind SHRA
will affect the regional waters and mainly the windward side and
north coastal areas of PR. Brief MVFR conds and MTN top obscr psbl
mainly ovr E interior of PR til 18/14Z due to low clds and few SHRA.
SCT OCNL BKN lyrs nr FL025...FL050. Aftn convective dvlpmnt with
VCSH mainly at TJBQ/TJMZ btw 18/16-23Z. E-NE winds at 5-10 kts incr
to 15-20 knots with gusts to near 30 knots and sea breeze variations
fm 18/13Z-18/22z.

&&

.MARINE...Choppy marine conditions will continue to prevail for
the next several days. Seas between 4 and 6 feet are expected,
with occasional seas up to 8 feet. East winds between 15 to 20
kts are expected to prevail across the local waters. Therefore,
small craft should exercise caution. There is a high risk of rip
current for the north central and northwestern beaches of Puerto
Rico, and the eastern tip of Saint Croix. There is a moderate risk
elsewhere.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 90 79 89 78 / 50 50 30 40
STT 90 78 89 79 / 30 40 40 50

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
346 AM AST Tue Jul 19 2022

.SYNOPSIS...Saharan dust in less concentration will continue to
linger across the area today. Passing showers are expected at
times during the morning hours, followed by afternoon convection
due to the combination of local effects and daytime heating. A
strong tropical wave is expected late Wednesday into Thursday,
enhancing the potential for shower activity and thunderstorms.

&&

SHORT TERM...Today through Thursday...

A mid to upper trough continued just north of the region while
the upper ridge extended southwest across the northern Leeward
islands into the northeast Caribbean. The upper ridge is forecast
to shift westward across the region by Thursday. In the meantime,
surface high pressure anchored across the north central Atlantic
will maintain moderate easterly trades across the region but
expected to increase by Thursday following the passage of a
vigorous tropical wave along with a surge of Saharan dust.

For the rest of the morning hours expect the proximity of the upper
trough to continue to enhance the passing showers which will affect
the windward side and portions of the north coastal areas of the
islands. Later today into Wednesday an induced surface trough is
forecast to cross the region bringing another surge of low level
moisture across the area in the prevailing easterlies. This will
increase the chance for afternoon convection, combined with local
effects and daytime heating. Afternoon convection will again be
focused mainly over portions of the central interior and west
sections of Puerto Rico. Isolated shower activity is expected in and
around the U.S. Virgin Islands but should be mainly on the west-end
or downwind of the islands in the form of streamers. In addition
late afternoon and early evening showers may also stream across
portions of the San Juan metro where ponding of water on roads and
poor drainage areas will be possible in isolated areas. Minor urban
and small stream flooding will again be possible over portions of
the west sections of Puerto Rico.

Somewhat drier with breezy and hazy conditions are forecast for
early Wednesday with more typical passing morning showers followed
by afternoon convection focused over parts of the interior and west
sections of Puerto Rico. A few streamer-like showers may affect the
U.S. Virgin Islands from time to time. However this pattern is still
expected to quickly change by late Wednesday and during the
overnight hours, based on the latest model guidance which has been
persistent and continued to initialize fairly well. Expect
increasing instability and tropical moisture influx, as a vigorous
tropical wave is forecast to cross the region thus increasing the
chance for enhanced showers and thunderstorms. By then the potential
for urban and small stream flooding across portions of eastern
Puerto Rico and the U.S. Virgin Islands is moderate to high with
areas of heavy rains expected over portions of the islands. So far
the best potential for increased convection is late Wednesday into
Thursday for the USVI and the rest of the islands including PR by
early Thursday and the rest of the day. A high concentration of
Saharan dust will accompany and also follow this tropical wave
leading to rapid drying and breezy condition thereafter. However,
stay tuned as some adjustments may be made as far as the timing of
the arrival of moisture in advance of and trailing the wave.

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

A mid to upper-level ridge will establish over the local area for
the first half of the period. A drier air mass is expected across
the the region limiting the rainfall activity across the U.S.
Virgin Islands and Puerto Rico. However, some streamers could form
during the afternoon hours. The Saharan Air Layer (SAL) is also
expected to increase in concentration across the islands,
affecting the air quality and possibly the visibility in some
areas. Moving to the second half of the period, Sunday looks the
best day for showers activity. A weak tropical wave is forecasted
to cross the islands by early Sunday and during the day. This will
bring showers at times, and an increase in moisture content. Due
to the strong easterly winds, this wave will move fast and more
drier air once again will enter the local area. The latest GFS-20
model guidance continues to forecast a seasonal, but slightly
drier weather pattern over Puerto Rico and the U.S. Virgin Islands
for Monday and Tuesday. This pattern will linger through the end
of the long period, by then moisture pulled from the Caribbean
will place over the islands, enhancing unstable conditions aloft
and shower formation.

&&

.AVIATION...VFR conds at all terminals. Tradewind SHRA will cont
across the regional waters and en route btw the islands til 19/13Z
with brief MVFR conds psbl at TJSJ and USVI terminals. Mtn top obscr
over E interior sections of PR due to low clds and -RA. Aftn
convective development may bring VCSH/Isold VCTS at TJBQ/TJSJ
between 19/17-22Z. Wnds fm E at 5-10 knots, increasing to 15-20 kts
mainly fm E-ESE with higher gusts and sea breeze variations aft
19/14z.

&&

.MARINE...Mariners can expect choppy marine conditions for the
next several days. Seas between 4 and 6 feet are expected, and
winds up to 20 kts across the local waters. Therefore, small
craft should exercise caution. There is a high risk of rip current
for the north central and northwestern beaches of Puerto Rico.
There is a moderate risk elsewhere.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 89 78 88 75 / 30 50 50 90
STT 89 79 89 76 / 40 50 60 100

[cycloneye]

 https://twitter.com/TTMetOffice/status/1549393667579854850

[cycloneye]

 https://twitter.com/TTWeatherCenter/status/1549446756026486787

[cycloneye]

 https://twitter.com/TTWeatherCenter/status/1549511938518007810

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
357 AM AST Wed Jul 20 2022

.SYNOPSIS...Typical weather conditions will prevail today across
the islands. A tropical wave is forecast to move into the region
late this afternoon and overnight, increasing moisture and
instability across the area through Thursday. Active weather is
anticipated with the potential of heavy rainfall and
thunderstorms. Drier air and Saharan dust will return by Thursday
night.

&&

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

A mid to upper trough will lift further north of the region while
the upper ridge will shift westward across the region today
through Friday. The surface high pressure across the north central
Atlantic will maintain moderate easterly trades across the region
but will increase and become breezy by Thursday onwards following
the passage of a vigorous tropical wave later today through
Thursday. This will bring unsettled weather conditions to the
region followed by an extensive Saharan air layer with a moderate
to high concentration of suspended Saharan dust particulates.

For the rest of the morning, quick passing tradewind showers will
continue to affect the local waters and brush parts of the islands
from time to time. No significant rainfall accumulations are
expected but some showers may cause ponding of water on roads and in
poor drainage areas especially along the north and east coastal
areas. Afternoon convection will be focused mainly over the central
interior and west sections of Puerto Rico with mostly isolated
showers expected in and around the San Juan metro and the U.S.
Virgin Islands most of the day. However by late afternoon and
overnight expect, increasing cloud cover and better potential for
convective development as the aforementioned tropical wave will
quickly approach the islands while a weak ridge aloft will provide
good ventilation for convective development. By then the chance for
urban and small stream flooding will be more likely over portions of
the the U.S Virgin islands and eastern Puerto Rico. Ponding of water
on roads and poor drainage areas will be possible in isolated spots
over the west sections of Puerto Rico during the afternoon hours.

So far the best potential for increased cloudiness and enhanced
convective activity is during the late afternoon and overnight for
the USVI and surrounding waters, and the rest of the islands
including PR by early Thursday and through the late morning and
early afternoon hours. Periods of locally heavy rains and strong
gusty winds will accompany the convective activity at times thus
leading to urban and small stream flooding especially over portions
of eastern Puerto Rico as well as isolated areas in the U.S. Virgin
Islands. Thereafter, a moderate to high concentration of Saharan
dust will accompany and quickly follow this tropical wave leading to
rapid drying and breezy conditions. That said a drying trend is so
far expected by Friday with the more typical summer time weather
conditions expected along with hazy and breezy condtions.

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

A dry weather pattern is expected to prevail the first half of
the period. At the surface level, a drier air mass with patches of
moisture will be present across the area on Saturday. A mid-level
ridge will continue to promote stable conditions aloft, and is
expected to prevail as the dominant at least until late Saturday.
By early Sunday, a weak tropical wave is forecasted to cross the
islands. This will bring showers at times, and an increase in
moisture content. Due to the strong easterly winds, this wave will
move fast and more drier air once again will enter the local
area. Therefore, by Monday through Wednesday drier air and more
Saharan Air Layer (SAL) will return. A surface high pressure will
build, promoting stable conditions aloft. Shower activity is
forecasted to be limited. Although, passing showers across the
local waters and moving into the eastern portions of Puerto Rico
during morning hours are posible. Then, in the afternoon hours the
moisture available combined with the daytime heating and local
effects could cause scattered showers across western and central
interior Puerto Rico. The U.S. Virgin Islands are expected to have
mainly fair weather conditions.

&&

.AVIATION...VFR conditions at all local terminals durg prd. Ocnl
tradewind SHRA ovr regional waters to continue with in brief MVFR
conds enroute to TJSJ and USVI til 20/13Z due to low clds and -SHRA
with Mtn top obscr also psbl ovr Ern PR. Aftn convective development
may bring SHRA with Isold VCTS at TJBQ/TJSJ btw 20/16-22Z. A
tropical wave will increase TSRA/SHRA ovr E Caribbean, affecting the
USVI terminals aft 20/20Z and TJSJ aft 20/23Z. Wnds will be lgt/vrb
increasing to 15-20 kts with gusts up to 30 knots and sea breeze
variations aft 20/14Z.

&&

.MARINE...Marines can expect seas up to 6 feet across most of the
regional waters today. Moderate to fresh winds up to 23 kts will
maintain choppy marine conditions. A tropical wave will move
across the islands later today, resulting in gusty winds causing
deteriorating seas that could become hazardous at times. For
beachgoers, there is a high risk of rip currents for the beaches
of northwestern and north central Puerto Rico. Elsewhere, there is
a moderate risk in effect.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 88 75 86 78 / 40 80 90 40
STT 89 76 87 80 / 40 80 90 20

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
543 AM AST Thu Jul 21 2022

.SYNOPSIS...A tropical wave is currently affecting our region,
bringing showers and isolated clusters and bands of thunderstorms.
Rainfall totals are expected to reach one inch in a few places of
the USVI and up to 3 inches in of Puerto Rico. The wave axis is
currently around the U.S. Virgin Islands and will move across
Puerto Rico during the morning hours. There is a high rip current
risk of rip currents for the easternmost beaches of St. Croix.


&&

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

A tropical wave is bringing increasing showers and isolated clusters
and bands of thunderstorms. The wave axis is now around the U.S.
Virgin Islands and will move across Puerto Rico during the morning
hours. Since midnight, rainfall amounts have been up to one inch
over the local waters and up to one half inch over land. Rainfall
totals during the next 24 hours over the U.S. Virgin Islands are
expected to reach one inch in a few places and in Puerto Rico up to
3 inches.

The tropical wave has scattered showers with intense rainfall that
moves quickly and remains brief. However upper level divergence
patterns in the GFS build aggressively over the area due to high
pressure at 250 mb between 21/12-15Z and convective activity is
expected to increase proportionately. This area of divergence moves
over central Puerto Rico and builds between 21/15-18Z, so
thunderstorms will continue to grow aggressively on the back side of
the tropical wave over western Puerto Rico. Convective activity will
abate from east to west aft 21/21Z and overnight, however some
shower activity will remain in the eastern side of Puerto Rico due
to moist lower levels as patches of moisture pass through. Tomorrow,
although moisture is decreasing and stability is increasing some
showers and possibly a thunderstorm are expected in western Puerto
Rico during the afternoon. Isolated showers are possible elsewhere.
Then, beginning early Saturday morning, weak troughs at 700 mb begin
to move through the area with some moisture and shower activity will
increase again. At the same time, a weak upper low in the southeast
Caribbean will couple with a low northeast of the Leeward Islands
and the resulting trough will enter the local forecast area late
Saturday night or early Sunday morning. The showers on Saturday and
Saturday night are expected to favor the northern U.S. Virgin Islands
and the north half of Puerto Rico the most.

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

Next week will start off with a weak tropical wave that will cross
the forecast area. As this tropical wave crosses the region, rain
chances will increase along with moisture content. The seasonal
shower pattern should also be benefited from this moisture.
Precipitable water values will peak at around 1.9 inches, within
normal values for this time of the year, with more moist air with
higher precipitable water values staying offshore in the Caribbean
Sea. This wave will also move faster than usual due to strong
easterly winds that are also present, limiting rainfall
accumulations. As we head into Monday, drier air along with a
Saharan Air Layer (SAL) will reach the islands, eroding any
lingering moisture from the tropical wave and limiting rain chances
for the first half of the workweek. Precipitable water values should
stay at or below normal values during this time, leaving a limited
seasonal pattern of passing showers during the morning hours over
the local waters and reaching eastern municipalities of Puerto Rico
and shower activity in the afternoon across the western and central
interior municipalities of Puerto Rico during the afternoon hours
due to diurnal and local effects. The U.S. Virgin Islands are
expected to have mainly fair weather conditions during the first
half of the workweek with only possible passing showers during the
morning hours. Areas of relatively more humid air, but still within
normal values, will reach the forecast region to start off Thursday,
due to a nearby tropical wave, with the bulk of humidity associated
with it remaining east of the forecast area by the end of the long
term period.


&&

.AVIATION...Trop wave to mov thru area and exit by 21/18Z. TSRA ovr
lcl waters and arnd USVI. Incrg clds and SHRA thru 21/18Z with brief
MVFR/IFR conds and mtn obscurations. Aft 21/14Z TSRA ovr PR to incr.
Sfc winds E 10-20 kt with gusts to 30 kt psbl nr TSRA bcmg ESE aft
trop wave psg. Max winds ESE 30 kt abv FL500, but winds ESE-ENE up
to 25 kt blo FL250.


&&

.MARINE...Moderate to fresh easterly winds will continue to
maintain choppy marine conditions during the next several days. A
tropical wave will move across the area today, bringing locally
hazardous conditions due to winds and increased thunderstorm
activity. There is a high rip current risk of rip currents for
the easternmost beaches of St. Croix. There is a moderate risk of
rip currents for most other beaches in the area.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 86 78 88 78 / 90 40 30 60
STT 87 80 90 79 / 100 20 30 60

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
523 AM AST Fri Jul 22 2022

.SYNOPSIS...

A drier pattern is expected today with showers and possible
isolated thunderstorms during the afternoon hours over the
western and interior municipalities of Puerto Rico. Drier air
along with Saharan Dust will affect the region through early this
evening, causing hazy skies. Heat indices between 102 and 105
degrees are expected, especially in the northern coastal plains.
Another increase in moisture and instability is expected for this
weekend.

&&

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

The tropical wave that passed through the U.S. Virgin Islands and
Puerto Rico yesterday is now over and south southwest of Haiti. Some
moisture has curled back into the local Atlantic waters from the
crest of the wave, generating showers and a few thunderstorms
earlier last night, but generally drier air is moving into the area.
High pressure at the surface from the Azore Islands to Florida is
driving easterly trade winds of 15 to 20 knots. At mid levels, high
pressure is also north of the Leeward Islands at 30 degrees north.
It will drift slowly north during the periods. At upper levels, high
pressure over the area will move west to over Hispaniola while a cut-
off low moves across the Windward Islands and through the
southeastern Caribbean.

Moisture will vary from 1.25 inches to 1.8 inches during the period
with two intervening spikes of moisture (representing the high
limits of the range) intervening Saturday morning and early Sunday
morning. Since 500 mb temperatures will continue between minus 5.5
and minus 4.5 degrees C, only isolated thunderstorms are expected,
if any are able to develop with the more limited moisture seen in
the afternoons each day. Although very localized urban and small
stream flooding could occur in western Puerto Rico only scattered
showers with benevolent rainfall are expected otherwise. Some
scattered showers each night and early morning are also expected in
eastern Puerto Rico and around the U.S. Virgin Islands.

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

A weak tropical wave will continue crossing the forecast area,
moving westward, during the overnight into the early afternoon hours
on Monday to start the workweek. Recent models show the moist air
mass related to this tropical wave having precipitable water values
above 2 inches, with is above normal for this time of the year. Rain
chances will increase, especially for eastern Puerto Rico during the
overnight to early morning hours as the typical morning seasonal
pattern is influenced by the available above normal moisture. The
relatively fast movement of the wave due to the presence of strong
easterly winds could also limit total rainfall accumulations. This
tropical wave will be followed by drier air along with a Saharan Air
Layer (SAL) that will reach the forecast area, eroding any lingering
moisture and limiting rain chances for the rest of the first half of
the workweek. During this period the mid-levels will be dry,
especially on Tuesday into Wednesday. Precipitable water values
should stay at or below normal values during this time, leaving a
limited seasonal pattern of passing showers during the morning hours
over the local waters and reaching eastern municipalities of Puerto
Rico and shower activity across the western and central interior
municipalities of Puerto Rico during the afternoon hours due to
diurnal and local effects. After the passing of the tropical wave,
the U.S. Virgin Islands are expected to have mainly fair weather
conditions during the rest of the first half of the workweek with
only possible passing showers during the morning hours. Models show
areas of relatively more humid air, but still within normal values,
will reach the forecast region by Thursday and Friday before an area
of high moisture creeps into the easternmost local waters at the
end of the long term period.

&&

.AVIATION...Drier air behind the trop wave is arriving slowly, so
some residual showers are still over the local waters with -SHRA
also over the ern tip of PR. TSRA also linger alg the north coast of
the DR from MDPP to Samana. Sfc winds less than 10 kt in land
breezes and easterly flow bcmg aft 22/14Z 10-20 knots with gusts to
26 kt with sea breeze influences. Aft 22/18Z SHRA to dvlp ovr wrn
and interior PR with a slight chance of a thunderstorm, MVFR conds
and mtn obscurations. Max winds ESE-SE 20-30 kt btwn FL230-300.


&&

.MARINE...Moderate to fresh easterly winds will continue to
maintain choppy marine conditions during the next several days.
Moisture from the tropical wave that passed through the area
yesterday is moving west, shower activity will continue to subside
except for brief isolated to scattered showers over the local
waters and in the Mona Channel. A high rip current risk is in
effect through this afternoon for the beaches of San Juan and
Vicinity, becoming moderate tonight. A high rip current risk is
in effect for the north-central and northwestern beaches today and
tonight. Most other beaches in PR and the USVI will have a
moderate risk of rip currents.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 88 78 88 78 / 30 60 50 70
STT 90 79 89 78 / 30 50 50 30

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
552 AM AST Sat Jul 23 2022

.SYNOPSIS...Several patches and bands of moisture will continue
moving through the forecast area during the morning hours.
Another band of moisture is expected to move through the area
tonight. There is a slight chance of thunderstorms with heavy
rainfall and brief gusty winds this afternoon across portions of
southwest Puerto Rico. Late Sunday into early Monday a tropical
wave could move through the area, increasing moisture especially
on Monday morning, with moisture decreasing after Monday morning.
Temperatures will be cooler than yesterdays due to an ENE
component to the wind flow; only a few areas along the north coast
will have heat indices above 102 degrees.


&&

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

High pressure at the surface extends from a high near the Azore
Islands to Florida generating moderate to locally fresh easterly
trade wind flow to the local area. Several bands of moisture are
embedded in this flow, the first of which is moving into the forecast
area now, with the best moisture southeast of Saint Croix. Scattered
showers are moving over the local waters and have dampened U.S.
Virgin Islands and the northeast half of Puerto Rico with up to one
tenth and six tenths of an inch respectively. Another band is
expected to move through the area tonight with similar results. The
next more significant feature to move through the area will be a
tropical wave/wind surge. This is well depicted in the GFS and is
expected to arrive during the evening on Sunday.

At upper levels, low pressure in the southeast Caribbean is
producing a weak jet of 30-40 kts across Saint Croix. The low will
move west northwest and the trough associated with it will cross
Puerto Rico around 24/21Z Sunday afternoon. This will enhance the
activity at the surface and some isolated thunderstorms across the
area Sunday night and early Monday are possible. Drier air will
follow, but scattered showers over Puerto Rico are still expected
Monday.

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

Lingering moisture from the weak tropical wave will be eroded by
Tuesday as a mass of drier air along with a Saharan Air Layer
(SAL) reaches the forecast area, limiting rain chances for the
most of the first half of the workweek. During this period the mid
levels will be dry, especially on Tuesday into Wednesday.
Precipitable water values should stay at or below normal values
during this time, leaving a limited seasonal pattern of passing
showers during the morning hours over the local waters and
reaching eastern municipalities of Puerto Rico and shower activity
with possible thunderstorms across the western and central
interior municipalities of Puerto Rico during the afternoon hours
due to diurnal and local effects. During this time, the U.S.
Virgin Islands are expected to have mainly fair weather conditions
with only possible passing showers during the morning hours.
Winds should be generally easterly during the long term period,
but will have an ENE component at times. An upper level trough and
patches of relatively more humid air, but still within normal
values in terms of precipitable water values, reaching the
forecastarea on Wednesday through Friday will promote higher
rain chances compared to Tuesday. Models currently show an area of
relatively higher moisture reaching the forecast area late Friday
and into the weekend. This is due to another tropical wave that
will affect the area, from late Friday through the end of the
forecast period. With humid air with precipitable water values
near 2 inches, reaching the forecast region and 500 mb
temperatures cooling down to around -6.0C to -7.0C, next weekend
appears to have the best chance, during the long term period, for
shower and thunderstorm activity to affect our region.


&&

.AVIATION...A band of moisture is moving thru ern PR and the
USVI with sct SHRA on ENE flow of 10-15 kt. Sfc winds will incr to
12-22 kt with hir gusts in sea breezes aft 23/13Z. SHRA will dcrs in
ern PR and the USVI but incr in W and SW PR aft 23/15Z. Mtn
obscurations, brief MVFR conds and a slight chc of TSRA are
possible there. Max winds ENE-E 30-35 kt btwn FL230-260.


&&

.MARINE...Moderate to fresh easterly winds will continue to
maintain choppy to hazardous marine conditions for the next
several days. Scattered showers are expected at times across the
local waters. A tropical wave/wind surge will pass Sunday night
through Monday with some additional thunderstorms. A high rip
current risk is in effect for the northern beaches of Puerto Rico
and St Croix. Most of the other beaches have a moderate risk of
rip currents.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 78 89 77 89 / 60 40 80 70
STT 78 90 77 90 / 40 40 70 30

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
544 AM AST Sun Jul 24 2022

.SYNOPSIS...
Patches and bands of moisture are currently moving through the
forecast area and should continue to do so during the morning
hours for this afternoon shower activity is expected along with
possible isolated thunderstorm for western Puerto Rico. A
tropical wave is forecast to cross the area late tonight through
early Monday, increasing the chances of shower and thunderstorm
activity. Moderate to locally heavy rains could cause ponding of
water on roads and in poor drainage areas. Breezy conditions will
prevail along with choppy to hazardous marine conditions.

&&

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

High pressure at the surface extends from a high near the Azore
Islands to Georgia generating moderate to locally fresh easterly
trade wind flow across the local area. This high is expected to
continue much as it is through the rest of the period. Much of the
eastern Caribbean has precipitable water values of 1.75 to 1.9
inches due to a tropical wave transiting the area today. The GFS
does show considerable veering of the winds during the day, although
late today winds will return to nearly easterly due to the next
feature. The moisture from the tropical wave extends north to the
next and more significant feature to move through the area which
will be a wind surge. This is well depicted in the GFS and the TPW
products and is expected to arrive in the northeast corner of the
forecast area by mid-afternoon and before midnight in the U.S.
Virgin Islands and San Juan tonight. The wind surge will be somewhat
muted at the surface but winds of 30 to 40 knots will be seen from
the east southeast beginning as early as 25/12Z Monday morning.
Winds at these levels will gradually decrease to 25 to 30 knots by
26/15Z Tuesday morning.

At upper levels, low pressure in the southeast Caribbean was
producing a weak jet of 25-30 kts across Puerto Rico. The low will
move west northwest and the trough associated with it will cross
Puerto Rico around 24/21Z Sunday afternoon. The upper level low will
weaken, but will still be near the area on Tuesday. This will
enhance the activity at the surface and some isolated thunderstorms
across the area Sunday night and early Monday are possible. Drier
air will follow above 850 mb, but scattered showers from low level
moisture will persist. Isolated thunderstorms are possible Monday
afternoon with showers in western Puerto Rico. Scattered showers
will persist through Tuesday over Puerto Rico due to this moisture
and even numerous Monday night.

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

Models currently show a Saharan Air Layer lingering but gradually
decreasing at the start of the long term period. Areas of relatively
higher moisture, but still within normal values for this time of the
year, will make their way to the forecast area from through Friday
with models currently show the driest mid levels on Friday.
Precipitable water values should stay at around normal values
through the end of the workweek. A seasonal pattern of passing
showers during the overnight and morning hours mainly affecting
eastern Puerto Rico and shower activity with possible thunderstorms
across the western and central interior municipalities during the
afternoon hours due to diurnal and local effects. Through the end of
the workweek, the U.S. Virgin Islands are expected to have mainly
fair weather conditions with only possible passing showers during
the morning hours. Winds should be generally easterly during the
long term period and an upper level trough will affect the area. The
weekend appears to have the best chance, during the long term
period, for shower and thunderstorm activity to affect our region.
This is due to another tropical wave that will reach the area, from
early Saturday through the end of the forecast period. For the
weekend, models are currently showing precipitable water values of
near 2 inches, above normal values, and relatively cool 500mb
temperatures of -6.0C and -7.0C.


&&

.AVIATION...A band of moisture is ovr the FA with sct SHRA on ENE
flow of 10-15 kt. Sfc winds will incr to 10-20 kt with hir gusts in
sea breezes aft 23/13Z. SHRA will dcrs in ern PR and the USVI but
incr in wrn and interior PR aft 23/15Z. Mtn obscurations, brief MVFR
conds and a chc of TSRA are possible there. Max winds NE 25-30 kt
btwn FL335-350.


&&

.MARINE...Fresh east to northeast winds will maintain choppy to
hazardous marine conditions. Scattered to numerous showers are
expected at times across the local waters. A tropical wave and
wind surge is forecast to cross the regional waters tonight
through early Monday increasing the chance for additional
thunderstorms and strong gusty winds across the regional waters. A
high risk of rip currents is in effect for the northern and
eastern beaches of Puerto Rico, and for the beaches of Culebra and
St. Croix.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 89 77 89 78 / 70 100 70 50
STT 90 77 90 78 / 60 90 30 30

&&

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
457 AM AST Mon Jul 25 2022

.SYNOPSIS...Flooding, waves, winds, and heat indices are
potential weather hazards at a slight to moderate impact levels
during the short-term forecast. Increased shower and thunderstorm
activity could lead to localized minor flooding today. Although a
Saharan Air Layer and associated drier air mass will maintain fair
weather conditions and hazy skies once the tropical wave exits
the forecast area, a typical pattern punctuated by afternoon
showers and isolated thunderstorms across the west can still be
expected. Heat indices could peak into the lower 100s each
afternoon. Breezy to windy conditions will maintain hazardous seas
and life- threatening rip currents.

&&

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

A tropical wave will continue to move across the region today,
bringing and increase in shower and isolated thunderstorm activity
over the local waters and portions of the islands. So far during the
overnight hours, up to half an inch of rain was estimated across
portions of eastern and southeastern Puerto Rico. A wind gust of 26
mph was observed in Carolina with the showers, and the doppler radar
suggested slightly higher gusts with the iso thunderstorms across
both Atlantic and Caribbean coastal waters. Latest scatterometer
wind data indicated 20-25 kt trades pushing quickly westward the
wave. There is some drier air with Saharan dust intrusion reaching
the northeastern Leewards, while the bulk of moisture content
associated to the wave has crossed the Windward Islands. Therefore,
the best window for rainfall activity across the USVI and eastern PR
is through early this morning, and across portions of the interior
and western PR during the afternoon hours. Ponding of water in roads
and localized urban and small stream flooding is expected with this
activity.

For tonight into Tuesday, breezy and hazy conditions, with limited
shower activity are expected to prevail across the islands, as a
Saharan Air Layer brings drier air aloft and Saharan dust. However,
trade winds are forecast to turn more from the east-northeast, and
brief trade wind showers are possible across the USVI and
northeastern PR during the night. Then, locally induced afternoon
showers should favor the southwestern portions of PR. Across the
USVI and eastern PR, light showers from streamers could develop
downwind of the islands. On Wednesday, a mid-level trough is
expected to move from the east across the region, while a TUTT-low
moves just north of Hispaniola. This should briefly relax the trade
wind cap and enhance diurnal convection, compared to Tuesday.

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

The inherited weather forecast is still on track. A more seasonal
weather pattern is expected to prevail across the forecast area,
with passing showers affecting the eastern portions of Puerto Rico
during the morning and showers with thunderstorms across the western
and central interior municipalities during the afternoon. A
generally easterly surface wind flow will prevail through the end of
the week. Expect this typical weather pattern to remain through at
least the end of the workweek. On Friday, conditions will gradually
deteriorate as the tropical wave approaches the islands. This will
cause winds to vary in direction, with a slightly northeasterly
component. Latest guidances are showing precipitable water values
near the 2 inches, from Saturday through Sunday. GFS models
currently show significant moisture content in all levels of the
atmosphere, meaning that the potential for thunderstorm activity
will be present during the weekend. Therefore, flooding and ponding
of water on roads and poorly drained areas can occur. Conditions
will gradually improve early in the workweek as a mid-level high
position across the area, along with possible particles of Saharan
dust.

&&

.AVIATION...Tropical wave crossing the fcst area this morning. This
may cause TEMPO MVFR conds and mostly VCSH with Isold TSRA psbl
across the USVI terminals thru 25/13z and across the PR terminals
thru 25/18z. Mtn Top Obscr w/SHRA and low clds ovr Ern PR fm thru
25/14Z. In addition sudden wind gusts btw 25-30 kts psbl with
convective activity early in the prd. HZ due to Saharan dust will
increase across the region today during the afternoon, but VSBY will
remain P6SM.

&&

.MARINE...Fresh winds up to 25 knots will maintain choppy to
hazardous marine conditions through late Monday night. Therefore, a
Small Craft Advisory remains in effect due to building seas up to
8 feet across the offshore Atlantic waters. Today, these
hazardous conditions will spread into the offshore Caribbean
waters, the coastal waters of northern and eastern Puerto Rico,
and the surrounding waters of Vieques, Culebra, and the U.S.
Virgin Islands, where Small Craft Advisories are also in effect.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 89 78 88 78 / 70 20 40 50
STT 90 79 90 77 / 30 10 30 30

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
447 AM AST Tue Jul 26 2022

.SYNOPSIS...A surface high pressure across the central Atlantic
will maintain moderate to locally fresh east-northeasterly trades
today. Although a mostly fair weather conditions and hazy skies
will prevail today, a typical pattern punctuated by afternoon
showers and isolated thunderstorms across the west can still be
expected.

&&

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

Breezy and hazy conditions will continue across the islands today.
Limited shower development is expected, however, diurnally induced
afternoon showers could still develop downwind of the islands from
streamers and over the southwestern sections of PR. Rainfall amounts
should remain under an inch over southwestern PR. Seasonal
temperatures will continue between the high 80s to the low 90s
across the lower elevations, with heat indices in the high 90s. A
surface high pressure over the western Atlantic will continue to
promote northeasterly trades at 15-20 kt with higher gusts in
coastal areas. This should favor an advective pattern tonight, and
trade wind showers are expected to increase along the northern and
eastern sections of PR, as well across the USVI through early
Wednesday morning.

Saharan dust will continue to diminish through the rest of the short
term period. A weak mid-level trough is expected to cross the region
from the west during the day on Wednesday, and an upper-level low is
forecast to sink southwards from the Atlantic, just north of
Hispaniola. This should allow for the trade wind cap to relax
briefly, and winds are expected to turn more from the east. However,
the precipitable water content is forecast to remain just below
normal levels. Having said that, expect a slight increase in
measurable rainfall amounts compared to today over land areas,
particularly over western PR during the afternoon. Similar weather
conditions are expected to continue on Thursday, with trade wind
showers moving at times during the night/early morning hours across
the USVI and eastern sections of PR, followed by shallow afternoon
convection over western PR.

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

A seasonal weather pattern is forecast to prevail across the local
islands through the end of the workweek. Expect early morning
showers to affect the eastern portions of Puerto Rico and the U.S.
Virgin Islands and afternoon convection across the western and
central interior municipalities. The wind flow will remain out of
the east until Friday. Late Friday, weather conditions will
deteriorate as a tropical wave approaches the islands. This weather
feature will bring more moisture content to the forecast area, as
well as an increase in winds through the weekend. The wind flow
associated with this wave will have a slight northeasterly
component. Latest guidances still suggest precipitable water values
near the 2 inches from Saturday through Sunday. GFS models still
show significant moisture content in all levels of the atmosphere,
meaning that the potential for thunderstorm activity will be present
during the weekend. Therefore, flooding and ponding of water on
roads and poorly drained areas can occur. Early in the workweek, a
gradually improve in the weather conditions will be seen as a mid-
level high position across the region, along with possible particles
of Saharan dust. Therefore, expect typical weather conditions to
prevail during the first part of the week.

&&

.AVIATION...Mainly VFR conditions are expected to prevail across all
terminals during the next 24 hours. HZ expected due to Saharan dust,
but VSBY will remain P6SM. VCSH expected across all terminals.
However, tempo MVFR conditions are possible aft 27/00z across the
northern PR and USVI terminals due to increasing trade wind SHRA .

&&

.MARINE...Moderate to fresh winds will continue to maintain choppy
conditions across the waters. Seas of up to around 6 feet. There
is a high risk of rip currents for beaches across the north coast
and southeast coast of Puerto Rico, as well as eastern Culebra,
Vieques, and Saint Croix.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 89 77 86 77 / 40 50 50 40
STT 90 78 89 77 / 30 40 30 40

[cycloneye]

AFDSJU

Area Forecast Discussion
National Weather Service San Juan PR
434 AM AST Wed Jul 27 2022

.SYNOPSIS...A surface high pressure across the west central
Atlantic will maintain moderate to locally east-northeast trades
through most of the period. Consequently the overall weather
pattern will be mostly seasonal with fair weather skies and
improving hazy conditions for the rest of the week. Weatherwise,
expect more typical afternoon pattern with showers and only a
slight chance of isolated thunderstorms mainly across portions of
the west and interior section of Puerto Rico. Elsewhere, shower
activity should be mainly isolated in the form of streamers and
down-wind of the adjacent islands. Choppy wind driven seas will
continue through most of the week.

&&

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

A weak upper-level trough moving across the region, and a surge in
low-level moisture from the Atlantic waters and the Anegada Passage
is expected to bring passing showers through the morning hours
across the USVI and the east/northern sections of Puerto Rico. Then,
diurnally induced afternoon showers with possible isolated
thunderstorms are expected to develop across western PR. This
activity may cause localized urban and small stream flooding.
Steering winds should continue from the east to northeast at 15-20
knots through the short term period.

A ridge pattern over the southwestern Atlantic and troughiness
across the western Caribbean should continue to promote a zonal flow
with drier air intrusion across the northeastern Caribbean through
Friday. Therefore, a drying trend is expected across the islands in
general. Precipitable water content is forecast to peak near 1.75
inches today, and bottom out to under an inch on Friday morning.
However, shower and thunderstorm activity is expected to increase
between late Friday night through early Saturday morning, as a fast
moving tropical wave streams across the region. Breezy conditions,
and a slight to elevated flood threat is expected with the wave
passage.

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

Models still show an increase in tropical moisture and instability
as a tropical wave moves through the forecast area during the
weekend. The wind flow associated with this wave will have a
slight northeasterly component, and the winds are expected to
increase. The most updated guidance continues to suggest
precipitable water values near to above the 2 inches on Saturday.
GFS model shows most of the rainfall and thunderstorm activity
occurring on Saturday, as the significant moisture content in all
levels of the atmosphere is seen during that period. Nevertheless,
similar weather conditions are expected on Sunday as well.
Therefore, flooding and ponding of water on roads and poorly
drained areas can occur. Early in the workweek, a gradual
improvement in the weather conditions will be seen as a mid-level
high position across the region, along with possible particles of
Saharan dust. Therefore, expect typical weather conditions to
prevail during the first part of the week. Midweek, conditions
will deteriorate again as another tropical wave reaches the
islands. Current guidance suggests up to 1.5 and 2 inches of rain
for this event. The latest model run shows all the significant
moisture content at the surface and upper levels of the
atmosphere. Therefore, expect patches of moisture from time to
time, but most of the activity will be due to diurnal effects.

&&

.AVIATION...Mainly VFR conditions are expected to prevail across all
terminals during the next 24 hours. However, trade wind showers may
cause brief MVFR cigs across TJSJ and the USVI terminals during the
morning hours. Iso thunderstorm development is possible across
western PR this afternoon, but VCSH should prevail in general with
the afternoon convection across mainland PR. Winds will continue
from the east, increasing 12-17 kt with higher gusts and sea breeze
variations after 14z.

&&

.MARINE...Today, expect a slight diminish in winds. By the end of
the weekend winds area forecast to pick up again. Overall
easterly winds with seas between 3 to 6 feet can be expected.
Small craft operators should continue to exercise caution due to
the wind driven seas.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 88 77 86 77 / 50 40 30 30
STT 88 77 88 77 / 30 40 40 10

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
450 AM AST Thu Jul 28 2022

.SYNOPSIS...Expect mainly fair weather conditions to prevail
today. Nevertheless, patches of moisture embedded in the trade
winds will support the seasonal shower pattern. A surface-induced
trough and a passing tropical wave will increase the potential for
showers with isolated thunderstorms from Friday evening into
Saturday, followed by a return of drying conditions by mid-day
Sunday into early next week.

&&

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

Trade wind showers will continue to move across the regional waters
and across portions of the USVI and east/northern PR through the
morning hours. Moisture associated to this, in combination with the
sea breeze convergence and daytime heating will lead to the
development of afternoon showers across portions of western PR.
Moderate to locally heavy rains could lead to ponding of water on
roadways and poor drainage areas to localized minor flooding.
Isolated thunderstorms may develop over the western coastal waters
during the late afternoon/evening hours. Across the USVI and
east/northern PR, east to northeasterly trades will promote an
advective pattern across the local waters and showers will increase
once again during the night into early Friday morning.

During the day on Friday, drier air ahead of a tropical wave should
cause a decrease in the coverage and intensity of the afternoon
convection across the islands. This will be short-lived, as a
tropical wave with PWAT values around 2.25 inches, enters the
eastern Caribbean and streams across the USVI and PR between Friday
night into Saturday morning. Breezy conditions and an elevated flood
threat due to thunderstorms and scattered to locally numerous
showers across the islands is expected with the wave passage. As
winds turn more east to southeast, lingering moisture and diurnal
effects should feed afternoon convection over west/northwest PR, and
latest model guidance still suggest a trailing plume of moisture
reaching the USVI and eastern sections of PR through the evening
hours. A Saharan Air Layer is expected to follow quickly and promote
a drying trend and hazy skies during the overnight hours.

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

Latest guidance remains in agreement with the previous discussion.
On Sunday, expect the tropical wave to continue to move across the
islands, leaving moisture and breezy conditions in its wake. The
wind flow associated with this wave is forecast to be out the east
with a slight northeasterly component. Models continue to suggest
precipitable water values near the 2 inches for Sunday. By mid-day
Sunday, a mass of dry air is forecast to move through the region.

Early in the workweek, an improvement in the weather conditions will
be seen, as a mid-level high positions across the forecast area,
along with possible particles of Saharan dust. Therefore, expect
typical weather conditions to prevail during the first part of the
week.

Conditions will deteriorate again as another tropical wave reaches
the islands by midweek. Expect up to 1.5 inches of rain during this
event. The latest model run shows all the significant moisture
content at the surface, meaning that more widespread showers from
time to time can be expected, as well as more localized afternoon
shower activity associated to sea breeze convergence and diurnal
heating.

&&

.AVIATION...Mainly VFR conditions are expected to prevail across all
terminals during the next 24 hours. However, trade wind showers may
move at times across the USVI and east/northern PR terminals during
the morning hours. Winds will continue from the east, at 10-15 kt
with higher gusts and sea breeze variations after 28/14z. SHRA
expected to increase btw 28/22z-29/06z across the USVI terminals and
TJSJ/TJBQ.

&&

.MARINE...Moderate to locally fresh trade winds up to 20 knots
will maintain choppy marine conditions through the end of the
workweek, with choppy seas up to 6 and 8 feet. Small craft
operators should exercise caution across local waters and
passages. Increasing winds will cause marine conditions to
deteriorate further during the weekend, as a tropical waves
approaches de area. There is a high risk of rip currents for
beaches across the north- central to the northwest coast of Puerto
Rico. A moderate risk remains in place for most remaining local
beaches.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 88 78 87 78 / 30 50 40 60
STT 89 77 89 79 / 30 10 50 60

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
430 AM AST Fri Jul 29 2022

.SYNOPSIS...Life-threatening rip currents are the main hazard of
the day. Today, mainly fair weather conditions will prevail,
although patches of moisture embedded in the trade winds will
support the seasonal shower pattern with afternoon convection
across the west. A passing tropical wave will increase the
potential for showers with isolated thunderstorms from Friday
evening into Saturday morning, followed by a return of a Saharan
Air Layer and drying conditions by Sunday into early next week.

&&

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

An area of low-level cloudiness and moisture will continue to move
from the Atlantic and eastern waters today. This will continue to
promote trade wind showers across portions of the USVI and
east/northern PR through the morning hours. Once again this
afternoon, the combination of the available moisture with the sea
breeze convergence and daytime heating will lead to the development
of afternoon showers across portions of western PR. Moderate to
locally heavy rains could lead to ponding of water on roadways and
poor drainage areas to localized minor flooding.

By late tonight into early Saturday morning a tropical wave will
bring an increase in shower activity across the USVI and the eastern
half of PR. Breezy conditions and an elevated flood threat is
expected with the wave passage. Winds will turn from the east to
southeast during the day and through Sunday. Lingering moisture and
diurnal effects will feed afternoon convection over western PR and
downwind of the islands on Saturday. A Saharan Air Layer is expected
to follow quickly and promote a drying trend and hazy skies during
the overnight hours and through Sunday. However, locally induced
afternoon showers are still expected to develop over northwestern PR
on Sunday.

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

Weather conditions will improve during the first part of the long-
term forecast, as a mid-level high positions across the forecast
area. Particles of Saharan dust are forecast to make their way into
the region, limiting the potential rainfall activity. The wind flow
during the first part of the workweek will have a more northeasterly
component. By midweek, conditions will deteriorate as a tropical
wave reaches the islands. Expect up to 1.5 inches of rain with this
event. The latest models show most of the significant moisture
content at the surface. Therefore, expect more widespread showers
from time to time and a more localized afternoon shower activity
associated with sea breeze convergence and diurnal heating. As the
tropical wave exits the region, improving conditions will be seen
late in the workweek.

&&

.AVIATION...Mainly VFR conditions are expected to prevail across all
terminals during the next 24 hours. However, trade wind showers may
cause brief MVFR cigs across TJSJ/TJBQ and the USVI terminals during
the morning hours. VCSH expected at TJPS due to afternoon SHRA
developing over the Cordillera. Winds will have a more northeasterly
component today, increasing between 12-18 kt with higher gusts and
sea breeze variations after 14z.

&&

.MARINE...Moderate to locally fresh winds up to 20 knots will
maintain choppy marine conditions today with choppy seas up to 6
feet. As a result, small craft operators should exercise caution.
Increasing winds will cause marine conditions to deteriorate
further during the weekend, with the potential for Small Craft
Advisory criteria by Saturday.

There is a high risk of rip currents for beaches across northern
Puerto Rico. The high risk for the northeastern and eastern
beaches of Puerto Rico will remain until this afternoon, while
the northwestern and north central beaches will remain until
Sunday afternoon. A moderate risk remains in place for most
remaining local beaches.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 87 78 89 79 / 30 90 70 60
STT 89 79 89 80 / 30 80 50 50

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
507 AM AST Sat Jul 30 2022

.SYNOPSIS...A passing tropical wave will continue to support
showers and isolated thunderstorms with the potential for urban
and small stream flooding today, followed by rapid drying with the
entrance of a Saharan Air Layer and associated drier air mass by
tonight into early week. The next rain produced is expected by
midweek, followed by a set of tropical waves by the end of the
workweek into the upcoming weekend. In the meantime, expect the
typical shower pattern highlighted by afternoon convective
development over western sections. Increasing winds will maintain
choppy to hazardous marine conditions and life-threatening rip
currents during the next few days. Above- normal heat indices are
also expected.


&&

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

A tropical wave depicted on GOES-East imagery will bring a sharp
increase in moisture and breezy to windy easterlies today. The Total
Precipitable Water estimated by the satellite range between 1.90 and
2.10 (or even more) inches. This water content is above-normal for
July`s climatology (around the 75th percentile). In addition,
African Dust Particles are also present in our atmosphere, and some
haziness will also be present late today. This wave will promote
showery weather conditions across the islands, and thunderstorms may
affect the region too. Periods of moderate to heavy rain could
result in ponding of water in roads and poorly drained areas in
Puerto Rico and the U.S. Virgin Islands. We cannot rule out urban
and small stream flooding if persistent heavy rains affect the
islands, especially along the Cordillera Central, la Sierra de
Luquillo, the San Juan Metro-Area, or western PR. In addition to the
flooding threat, in coastal and urban areas without receiving
significant rainfall amounts, the combination between the maximum
temperatures and the moisture content could result in heat indices
above 100 degrees Fahrenheit by mid-morning into the afternoon.

Although patches of moisture embedded in the trades will promote a
seasonal weather pattern, consisting of passing showers across the
windward sections and afternoon convection across the western areas,
expect a drying trend after today`s wave. This dry air mass has
African Dust Particulate, promoting hazy skies throughout the short
term. Residents of Puerto Rico and the Virgin Islands should know
that on Sunday and Monday, the heat indices will reach and surpass
100s degrees Fahrenheit after mid-morning into the afternoon.

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

A surface high pressure meandering across the north Atlantic Ocean
will maintain a generally easterly wind flow at 10-20 mph through
the long-term forecast cycle. Nonetheless, various surface
features, including an induced trough and a set of tropical waves,
will cause winds to vary briefly in intensity and direction. These
same features are expected to produce measurable rainfall totals,
with the potential for ponding of water on roadways and poorly
drained areas to localized minor flooding. The first feature, a
surface-induced trough, will affect the area late Tuesday into
Wednesday, followed by a weak tropical wave on Thursday and yet
another broader tropical wave on Saturday. In the meantime, a
Saharan Air Layer and associated drier air will maintain generally
fair weather conditions and hazy skies. Daytime temperatures will
also vary with changes in the general wind flow, but heat indices
may peak into the lower to mid 100s each afternoon.


&&

.AVIATION...A tropical wave moving across the region, will bring
SHRA/TSRA, causing VCTS across the USVI this morning and later in
the afternoon. TSRA/SHRA will spread across most of PR by 30/15z and
will possibly affect TJSJ/TJPS/TJBQ. Winds will continue will
continue from the E/ESE around 10 kts, but gusty near SHRA. Winds
speed will range between 15 and 20 knots after 30/13z with sea
breeze variations and higher gusts near TSRA/SHRA.


&&

.MARINE...Increasing winds associated with the passage of a
tropical wave will maintain choppy to hazardous marine conditions
today. Across the local offshore Atlantic waters, where seas up to
7 feet are expected through early this afternoon, a Small Craft
Advisory remains in place. Elsewhere, small craft operators should
exercise caution due to moderate to locally fresh winds up to 20
knots and choppy seas of up to 6 feet. There is a high risk of rip
currents for beaches across the north coast of Puerto Rico and
beaches across the northern and eastern beaches of Culebra and
Saint Croix. A moderate risk of rip currents remains in place for
most remaining local beaches.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 87 79 89 80 / 80 50 50 30
STT 90 80 90 79 / 20 30 20 20