Caribbean - Central America Weather

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
557 AM AST Wed Mar 15 2023

...New SYNOPSIS, AVIATION, MARINE...

.SYNOPSIS...
Issued at 514 AM AST Wed Mar 15 2023

A recent pulse of swell is fading this morning along our coasts.
A second, stronger pulse will come in on Thursday night and
persist well into the weekend. Nevertheless marine conditions
will remain hazardous. Better than average moisture for March
continues over the area and will bring more showers to the
interior of Puerto Rico and the local waters. It should not result
in the heavy amounts seen yesterday. This moisture will persist
and then be met on Thursday by a cold front advancing from the
northwest. Drier weather is expected for the weekend and beyond,
but scattered showers from a shallow layer of moisture will
continue in the normal diurnal pattern.

&&

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

Weather-wise, the main feature that will affect the region will be a
cold front that will move through on Thursday. For today, passing
showers will continue moving across sectors of the eastern forecast
area as a patch of relatively more humid air persists over our area.
Satellite derived precipitable water (PWAT) shows normal to above
normal values over our the islands. Current model guidance show this
patch gradually moving northward as windflow becomes more southerly,
but not before afternoon convection begins due to diurnal heating
and local effects. Another active afternoon with showery weather is
expected today focused along the Central Cordillera with winds also
pushing showers northward and westward. Although dry air will filter
into the area from the south on Wednesday night, moisture related to
a frontal boundary and associated trough will approach the area from
the northwest as winds continue to veer. PWAT values above 1.5
inches, related to the frontal boundary will push into the area
by Thursday afternoon. Current model guidance indicates increasing
PWAT values of up to near and around 2 inches by Thursday night
as the cold front moves across the area. Increasing moisture, both
at surface and into the mid-to-upper levels, and instability will
promote yet another active afternoon on Thursday as the front
moves southwards, scattered to numerous shower activity should
focus mainly over interior and northeastern Puerto Rico, causing
ponding of water over roadways and poorly drained areas. Moisture
and showers related to the front should linger through Friday
morning and early afternoon, before drier, cooler air settles in
and winds become north to northeasterly to end the workweek.

&&

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

According to the GFS columnar moisture reaches a minimum Saturday
morning as drier air pushes into the area behind the cold front
that moved through Thursday and Thursday night. High pressure at
the surface will be north of Puerto Rico at around 29 north. This
high moves into the Central Atlantic ocean during the period but
the ridge that trails it remains across the Atlantic waters north
of us just north of 20 north. This will maintain the moderate to
fresh trade winds over the area that will begin on Thursday.
Moisture recovers somewhat Sunday through Tuesday, but mid levels
remain dry. At upper levels high pressure that was forced to
remain over South America and Panama, will begin to ridge into the
Central Caribbean and that ridge will approach the local area on
Wednesday.

Although the drier air invades behind the front the brisk winds
behind the front and a shallow moist layer that continue with few
breaks during the long term period will be able to generate some
scattered showers on the windward side of the island of Puerto
Rico during the night and morning hours. some convection may also
appear in western Puerto Rico during the afternoons, but amounts
will be light to to the invigorated trade winds.

The U.S. Virgin Islands will see only isolated showers during the
period, although a better chance exists during the overnight
periods through Tuesday.

&&

.AVIATION...
(06Z TAFS) Issued at 514 AM AST Wed Mar 15 2023

Overall VFR conditions will continue for all of the
local terminals today. Winds will be up to around 12 kts under a
generally southeasterly flow with sea breeze variations, with
winds veering to become more southerly as the day progresses.
Brief MVFR conditions possible due to showers reaching eastern
terminals. Afternoon shower activity could also impact mainly TJBQ
and TJSJ. Maximum winds W 35-45 knots btwn FL 240-480. Winds will
likely increase to above 50 knots around FL400 during the day.

&&

.MARINE...
Issued at 514 AM AST Wed Mar 15 2023

Seas at the outer buoy (41043) have dropped from 8 feet to
between 6 and 7.5 feet overnight. Seas at our inner buoy (41053)
have been steady between 5.5 and 6.0 feet. Periods have ranged
from 14 to 15 seconds at these buoys. Seas are expected to subside
only a little between now and Thursday midday. After which a
stronger swell of up to 10 feet from the north will enter the
area. Small craft advisories will continue in the Mona Passage and
the outer Atlantic waters through at least Sunday. For some of
the inner waters of the Atlantic ocean seas will drop below 7 feet
until Thursday night beginning late tonight. High surf and a high
risk of rip currents will continue for Puerto Rico through
Sunday. The U.S. Virgin Islands and Culebra will see a break
in the high surf beginning Thursday or Thursday night for no more
than 24 hours, before more serious conditions return on Friday.

&&

.SJU WATCHES/WARNINGS/ADVISORIES...
PR...High Rip Current Risk through Sunday afternoon for PRZ001-002-
005-008-010-012.

High Surf Advisory until 6 PM AST Sunday for PRZ001-002-005-008-
010-012.

High Rip Current Risk through late tonight for PRZ011-013.

VI...High Rip Current Risk through Sunday afternoon for VIZ001-002.

High Surf Advisory until 6 AM AST Thursday for VIZ001.

AM...Small Craft Advisory until 2 PM AST Sunday for AMZ711-741-742.

Small Craft Advisory until 2 AM AST Thursday for AMZ712-716-723.

&&

$$

LONG TERM/MARINE...WS
SHORT TERM/PUBLIC....MRR
PUBLIC/UPPER AIR...RVT

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
453 AM AST Thu Mar 16 2023

.SYNOPSIS...Variable weather conditions are expected today to the
approach of a cold front. Scattered to numerous showers and
isolated thunderstorms are also expected with this event across
Puerto Rico and the U.S. Virgin Islands. Another pulse of
northerly swell will arrive to the regional waters later today,
deteriorating marine conditions once again. There are several
advisories and rip-current statements in effect. Please visit our
marine section.

&&

.SHORT TERM...Today through Saturday

A cold front north of Hispaniola will continue to sink southwards
and it is expected to cross the region later this evening into
Friday morning. Light southerly winds converging with stronger
northerly winds will result in afternoon convection over the
interior and eastern half of Puerto Rico today. Then, as the front
push southwards, additional showers are expected across the rest of
PR and the U.S. Virgin Islands through the overnight hours. The mid-
to upper-level trough will promote colder than normal 500 mb
temperatures with the frontal passage and isolated thunderstorms
cannot be ruled out. Urban and small stream flooding is expected
with this activity, as well as isolated flash flooding.

A building low to mid-level ridge behind the front will promote
stable conditions and drier air intrusion across the area later on
Friday and through Saturday. Breezy and fair weather conditions in
general are expected to prevail across all the islands, especially
on Saturday. Daytime temperatures should range from the low to mid
80s across the eastern and northern coastal areas of PR, as well
across the USVI, while the south and west coast of PR could see
temperatures in the mid to high 80s.

&&

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

A surface high pressure located north of the area in the Central
Atlantic will maintain moderate to locally fresh trades over the
region. By Sunday into the beginning of the workweek, tropical
moisture will move over the islands increasing the potential for
shower development for most of the long-term period. Passing
showers will be observed across the eastern and northern portions
of Puerto Rico and the U.S. Virgin Islands during the overnight
and morning hours. Then, followed by afternoon convection across
the Central Interior and western Puerto Rico. The latest model
guidance (GFS) suggest a increase in moisture that will lead to
isolated to scattered showers across the region. The Precipitable
Water content between 1.50 to 1.75 inches, suggest in effect a
wetter weather pattern. Therefore, ponding of water in roads and
poor drainage areas may be possible. From Wednesday through
Thursday, a mass of drier air will filter into the local area,
limiting the shower formation across the local islands. Daytime
temperatures will remain in the mid to upper 80s along the coastal
areas and in the mid to upper 70s across the central interior.


&&

.AVIATION...Mainly VFR conditions expected thru 16/16z. Then, SHRA
with possible TSRA are expected to gradually increase from the
north, as a front moves across the local area. MVFR to tempo IFR
condtions are possible btw 16/19z-23z at TJSJ, spreading across the
rest of the terminals thru the overnight. Expect mtn top obscd.
Light southerly winds should prevail across all terminals, except
TJBQ/TJSJ where a northerly component is expected aft 16/14z. West-
northwest winds increasing 15-20 kt expected aft 17/00z.


&&

.MARINE...Another pulse of northerly swell is forecast to arrive
later today across the local Atlantic waters. Hazardous conditions
are expected and will persist throughout the weekend. Mariners can
expect seas that will increase up to 12 feet across the offshore
Atlantic waters and up to 8 feet in the rest of the waters and
Passages. Breaking waves will remain up to 14 feet, mainly along
the northern coastal areas of Puerto Rico. A High Surf Advisory is
in effect from the northwestern to northeastern beaches of Puerto
Rico, and Culebra. A Small Craft Advisory will start in effect
this afternoon for most of the regional waters. For beachgoers,
there is a high risk of rip currents along the northern exposed
beaches of Puerto Rico, Culebra, Saint Thomas, Saint John, and
Saint Croix.


&&

.SJU WATCHES/WARNINGS/ADVISORIES...
PR...High Rip Current Risk through Sunday afternoon for PRZ001-002-
005-008-010-012.

High Surf Advisory until 6 PM AST Sunday for PRZ001-002-005-008-
010-012.

VI...High Rip Current Risk through Sunday afternoon for VIZ001.

High Rip Current Risk from this evening through Sunday afternoon
for VIZ002.

AM...Small Craft Advisory from 2 PM this afternoon to 2 PM AST Sunday
for AMZ711.

Small Craft Advisory from 8 PM this evening to 2 PM AST Sunday
for AMZ712-741-742.

Small Craft Advisory from 2 AM Friday to 2 PM AST Sunday for
AMZ716-723.

&&

$$

SHORT TERM...DSR
LONG TERM....GRS

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
424 AM AST Fri Mar 17 2023

.SYNOPSIS...Breezy conditions under partly cloudy skies are
expected today across the local area. Light to moderate showers
are also expected across the islands during the morning hours.
Then in the afternoon hours, drier air will filter across the
region and slowly improving the weather conditions. Another
northerly swell pulse continue to move across the regional
waters. Marine conditions will remain hazardous for the rest of
the weekend.


&&

.SHORT TERM...Today through Sunday

Frontal passage across the region will promote cloudy skies and
showers throughout the day. Breezy conditions are expected as well,
with northerly winds gusting between 25-30 mph at times. Drying at
700 mb is expected later this afternoon, but shallow level moisture
will remain high through at least tonight. Therefore, light to
moderate periods of showers can be expected in general across the
islands today. Rainfall accumulations should remain in general under
an inch. A building low to mid-level ridge behind the front will
promote stable conditions and drier air intrusion across the area
during the weekend. Breezy and fair weather conditions in general
are expected to prevail across all the islands. However, showers
will increase by late Sunday, as winds turn more east to southeast
in response to the surface ridge building over the central Atlantic
and fragmented clouds and shallow moisture from the remnants of the
front reach the area once again.

&&

.LONG TERM..Monday through Friday...

A dominant surface high pressure in the central Atlantic will
continue to maintain moderate to locally fresh winds across the
region. By the beginning of the workweek moisture dragged by the
trades will enter the local area. This pattern is forecast to
enhance shower activity across the islands. Isolated to scattered
showers are expected across the eastern portions of Puerto Rico and
the U.S. Virgin Islands. Then, afternoon convection is posible
across the central interior and western portions of Puerto Rico. The
latest Precipitable Water Content Analysis (PWAT), suggest a wetter
weather pattern until at least mid-week with values ranging between
1.40 to 1.57 inches. Therefore, with the expected activity ponding
of water in roads and poor drainage areas is possible. By Wednesday
through Friday, a mass of drier air will enter to the local area.
Although, an area of tropical moisture will remain close to the
local area over the Caribbean waters. This moisture in combination
with daytime heating and local effects could enhance afternoon
showers across portions of the islands. By late Friday, an
approaching weak cold front will bring additional showers to the
CWA. Daytime temperatures will remain in the mid to upper 80s
along the coastal areas and in the mid to upper 70s across the
central interior. Heat indices will stay in the low to mid 90s
along the coastal portions of the islands.

&&

.AVIATION...Mainly VFR conditions expected across all terminals.
However, FROPA will continue to cause RA and BKN/OVC cigs abv FL050
through late this afternoon. Brief MVFR conditions cannot be ruled
out at TJSJ/TIST. Northerly winds increasing 15-20 kt with stronger
gusts aft 17/13z.

&&

.MARINE...Locally fresh northeasterly winds will prevail across
the regional waters today. A pulse of northerly swell is promoting
hazardous marine conditions through the weekend. Mariners can
expect seas up to 10 feet across the offshore Atlantic waters and
and the rest of the waters and Passages. Breaking waves will
remain up to 13 feet, mainly along the northern coastal areas of
Puerto Rico. A High Surf Advisory is in effect from the
northwestern to northeastern beaches of Puerto Rico, Culebra,
Saint Thomas, and Saint John. A Small Craft Advisory is also in
effect for most of the regional waters. For beachgoers, there is
a high risk of rip currents along the northern exposed beaches of
Puerto Rico, Vieques, Culebra, Saint Thomas, Saint John, and
Saint Croix.


&&

.SJU WATCHES/WARNINGS/ADVISORIES...
PR...High Rip Current Risk through Sunday afternoon for PRZ001-002-
005-008-010-012.

High Surf Advisory until 6 PM AST Sunday for PRZ001-002-005-008-
010-012.

High Rip Current Risk through Sunday afternoon for PRZ013.

VI...High Rip Current Risk through Sunday afternoon for VIZ001-002.

High Surf Advisory until 6 PM AST Sunday for VIZ001.

AM...Small Craft Advisory until 2 PM AST Sunday for AMZ711-712-716-
723-741-742.

Small Craft Advisory from 2 PM this afternoon to 2 PM AST Sunday
for AMZ726.

&&

$$

SHORT TERM...DS
LONG TERM....GRS

[cycloneye]

A weak tornado of EF-0 moved thru a town in eastern PR on Thursday March 16.

 https://twitter.com/NWSSanJuan/status/1636788424270299137

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
445 AM AST Sat Mar 18 2023

.SYNOPSIS...Life-threatening rip currents will persist into early
next week across Puerto Rico and the U.S. Virgin Islands. Fair
weather conditions expected today. The remnants of the front are
expected to move over the islands from the east on Sunday. A TUTT
induced perturbation is expected to bring showers on Tuesday and
Wednesday. Overall fair weather conditions are forecast for the
latter part of next week.


&&

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

As a surface high pressure located in the western Atlantic migrates
towards the central Atlantic will maintain breezy conditions across
the local area. Stable weather conditions are forecast to prevail
today into Sunday, as drier air filters into the region. The
Precipitable Water content analysis (PWAT) between 0.55 to 0.70
inches suggest dry air will inhibit shower development across the
area today. However, by late Sunday into Monday the shower activity
will increase as winds turn more from the east-southeast and the
remnants of the cold front reaches the local area. Isolated to
scattered showers are expected across the eastern portions of Puerto
Rico and the U.S. Virgin Islands. Then, followed by afternoon
convection across the central interior and western portions of
Puerto Rico. Daytime temperatures will remain in the mid to upper
80s along the coastal areas and in the mid to upper 70s across the
central interior. Heat indices will stay in the low 90s along the
coastal portions of the islands.

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

A TUTT low is expected to linger just east of the Leeward Islands
during the first part of the workweek, while a weak upper level ridge
holds over the region. An induced perturbation in the trades will
keep PWAT values between 1.50-1.75 inches through Wednesday.
Therefore, expect trade wind showers to increase in early morning
activity between the USVI and eastern PR, followed by afternoon
shower development over central and western PR. Thereafter, an
upper level trough will move over the islands on Thursday and 500
mb temps will drop to -9C, however, a drying trend is expected at
the lower levels, with PWAT falling once again to around an inch.
Uncertainty increases at the end of the long term period, as
there is some discrepancy between model solutions regarding the
position and intensity of a cold front, which should approach the
area on Friday.


&&

.AVIATION...Mainly VFR conditions expected across all terminals
through the forecast period. Winds will persist from the northeast
at 15 to 20 kts, with higher gusts after 18/13z.


&&

.MARINE...Lingering northerly swell and wind-driven seas will
continue to promote choppy and hazardous seas through early in the
week. Small Craft Advisories are in effect for most waters, please
refer to the Marine Weather Message (MWWSJU) for the latest
information.

In addition, there is a High Surf Advisory and a High Rip Current
Risk across most of the east, northern, and western beaches of
the islands. Please refer to the latest Coastal Hazards Message
(CFWSJU) and Surf Zone Forecast (SRFSJU) for detailed
information.


&&

.FIRE WEATHER...Elevated to critical fire weather conditions are
expected across the southern coastal plains of Puerto Rico today.
Drier conditions and stronger winds compared to yesterday are
expected. Therefore, a Fire Danger Statement was issued for the
southern coast of PR.

&&

.SJU WATCHES/WARNINGS/ADVISORIES...
PR...High Rip Current Risk through Monday afternoon for PRZ001-002-
005-008-010-012-013.

High Surf Advisory until 6 PM AST Sunday for PRZ001-002-005-008-
010-012.

VI...High Rip Current Risk through Monday afternoon for VIZ001-002.

High Surf Advisory until 6 PM AST Sunday for VIZ001.

AM...Small Craft Advisory until 2 PM AST Monday for AMZ711-723-741.

Small Craft Advisory until 2 AM AST Monday for AMZ712.

Small Craft Advisory until 8 PM AST Sunday for AMZ716.

Small Craft Advisory until 8 AM AST Sunday for AMZ726-742.

&&

$$

AVIATION/SHORT TERM...GRS
FIRE WEATHER/LONG TERM/MARINE...DSR

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
353 AM AST Sun Mar 19 2023

.SYNOPSIS...Life-threatening rip currents will continue through
early in the week across Puerto Rico and the U.S. Virgin Islands.
The remnants of an old frontal boundary will move over the
islands from the east today. Moisture embedded in the trade winds
is expected to bring showers across the islands through midweek.
Fair weather conditions are forecast for the latter part of the
week.


&&

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

As the mid-level ridge migrates from the central to the northeast
Atlantic, winds will become from the east-southeast. Today, patches
of shallow moisture will continue to filter across the eastern
portions of Puerto Rico and the U.S. Virgin Islands during the
morning hours. Then, in the afternoon hours shower development is
possible across the central interior and western portions of Puerto
Rico due to daytime heating and local effects. By late tonight into
Monday, remnants associated to an old cold front are expected to
reach the local area. Expect an increase in shower activity,
especially across the windward portions of the islands during the
overnight and morning hours. As the day progresses and the moisture
moves towards the northwestern portions of Puerto Rico, shower
activity is forecast to increase across those sectors. Nonetheless,
rainfall accumulations across the northwestern portions of Puerto
Rico and Central Cordillera will remain less than 1.0 inch. By
Tuesday onwards, a similar weather pattern will persist with trade
wind showers during the early morning hours between the USVI and
eastern Puerto Rico. Daytime temperatures will remain in the mid to
upper 80s along the coastal areas and in the mid to upper 70s across
the central interior. Heat indices will stay in the low 90s along
the coastal portions of the islands.

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

A TUTT low is expected to linger just east of the Leeward Islands
through Wednesday, while a weak upper level ridge holds over the
region. A reflection of the TUTT at 500 mb should enhance the
remnants of an old frontal boundary that are carried by the trade
winds from the Tropical Atlantic. Precipitable water (PWAT) content
will increase between 1.50-1.75 inches through midweek. Therefore,
shower activity is expected to increase across the islands thru at
least early Thursday. A drier air mass is forecast to move briefly
on Thursday afternoon, and PWAT falls to around an inch or less.
A weak front follows on Friday, with north-northeast winds
prevailing into the weekend as a surface high builds behind the
front over the southwestern Atlantic. Also, a building mid-level
ridge from the west across the Caribbean basing should provide
stable conditions and drier air intrusion to result in fair
weather conditions across the islands through the weekend.


&&

.AVIATION...Mainly VFR conditions will continue to prevail across
all terminals through the forecast period. VCSH expected for the TISX
after 19/14z and TJBQ between 19/17-23z. Winds will persist from the
ESE at 15 to 20 kts, with higher gusts after 19/14z.


&&

.MARINE...A northerly swell and choppy wind-driven seas will
continue to promote hazardous seas through early in the week. Small
Craft Advisories are in effect for most waters, please refer to the
Marine Weather Message (MWWSJU) for the latest information.

In addition, there is a High Surf Advisory and a High Rip Current
Risk in effect through Monday across most of the east, northern, and
western beaches of the islands. Please refer to the latest Coastal
Hazards Message (CFWSJU) and Surf Zone Forecast (SRFSJU) for
detailed information.


&&

.SJU WATCHES/WARNINGS/ADVISORIES...
PR...High Rip Current Risk through Monday afternoon for PRZ001-002-
005-008-010-012-013.

High Surf Advisory until 6 AM AST Monday for PRZ001-002-005-008-
012.

High Surf Advisory until 6 PM AST this evening for PRZ010.

VI...High Rip Current Risk through Monday afternoon for VIZ001-002.

High Surf Advisory until 6 PM AST this evening for VIZ001.

AM...Small Craft Advisory until 2 AM AST Tuesday for AMZ711.

Small Craft Advisory until 2 AM AST Monday for AMZ712.

Small Craft Advisory until 8 PM AST this evening for AMZ716.

Small Craft Advisory until 2 PM AST Monday for AMZ723-741.

Small Craft Advisory until 8 AM AST this morning for AMZ726-742.

&&

$$

SHORT TERM...GRS
LONG TERM....DSR

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
454 AM AST Mon Mar 20 2023

.SYNOPSIS...

Today, expect showers at times across the local islands due to
the remnants of an old front moving over the area. Hazardous
marine and coastal conditions persist. Winds will generally be
out of the east.

&&

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

An easterly perturbation with near to above-normal moisture content
will bring occasional clouds and showers across the U.S. Virgin
Islands, the eastern half of Puerto Rico, and surrounding waters
today. The local effects, sea breeze, and diurnal heating will
promote afternoon convection across the interior and western
sections of Puerto Rico. Afternoon showers may result in ponding of
water in poorly drained areas with the heaviest rain activity.

Hazardous breaking waves will maintain dangerous surf conditions
across the Atlantic Coastline of Puerto Rico and Culebra today. In
addition, life-threatening rip currents are likely along the beaches
from Aguada to Ceiba, Culebra, northern Vieques, and the north and
east coasts of St Thomas/St John and St Croix.

A TUTT-Low lingering east of the Lesser Antilles will induce surface
perturbations that the easterly winds will carry across the U.S.
Virgin Islands and Puerto Rico region Tuesday and Wednesday.
Therefore, expect a mixture of clear skies with the advection of
occasional clouds/showers. A dry and cool air mass will arrive
across the islands by Wednesday afternoon or evening, limiting rain
activity and promoting pleasant night temperatures.

&&

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

Early on Thursday, expect showers associated with a TUTT-low to
linger across the islands. Nevertheless, a drier air mass will
move briefly on Thursday afternoon, and PWAT values will fall to
around an inch or less. On Friday, a weak front will move across
Puerto Rico and the U.S. Virgin Islands, with prevailing east-
northeast winds into the weekend, as a surface high builds behind
the frontal boundary over the southwestern Atlantic. Latest model
guidance shows a building mid- level ridge from the west across
the Caribbean basing. This weather feature should bring stable
conditions and drier air resulting in mostly fair weather
conditions across the islands through at least the beginning of
the workweek.

&&

.AVIATION...VFR conditions will persist today. The easterly winds
will push fragments of clouds and SHRA/-SHRA this morning,
affecting IST/ISX/JSJ briefly. The sea breeze will promote SHRA
formation between 20/16-23z across the Cordillera Central, moving
near/across JBQ/IST/ISX; SHRA/-SHRA downwind from El Yunque may
also affect JSJ. Winds will continue calm to light/VRB thru
20/13z, then will return from the E-ESE at 15 kt with gusts up to
25-30 kt and sea breeze variations.

&&

.MARINE...Coastal and marine conditions remain hazardous today.
Latest observation from the San Juan buoy had seas around the 6
feet. Seas are expected to diminish and become choppy this
afternoon into tomorrow. At this time there are small craft
Advisories in effect until this afternoon. Coastal conditions
should remain hazardous for today mainly due to large breaking
waves up to 11 feet. As a result, high surf advisories and high
risk of rip currents remain in place for the northern, northeastern,
and northwestern coastal areas of Puerto Rico, as well as
Culebra, St. Thomas, and St. John.

&&

.SJU WATCHES/WARNINGS/ADVISORIES...
PR...High Rip Current Risk through Tuesday afternoon for PRZ001-002-
005-008-012.

High Surf Advisory until 6 PM AST this evening for PRZ001-002-
005-008-012.

High Rip Current Risk through this afternoon for PRZ010-013.

VI...High Rip Current Risk through Tuesday afternoon for VIZ001.

High Rip Current Risk through this afternoon for VIZ002.

AM...Small Craft Advisory until 8 PM AST this evening for AMZ711.

Small Craft Advisory until 2 PM AST this afternoon for AMZ723-
741.

&&

$$

SHORT TERM...CAM
LONG TERM....MMC
AVIATION...CAM

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
501 AM AST Tue Mar 21 2023

.SYNOPSIS...

Today, expect brief passing showers across the local
islands. However, the wettest pattern is forecast for today into
Wednesday due to an upper- level trough just north of the region.
There is currently a high rip current risk along the north facing
beaches of Puerto Rico, Culebra, St. Thomas, and St. John.

&&

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

Expect a mixture of sunshine and clouds across the islands with the
arrival of occasional brief passing showers today. The local
effects, sea breeze, and diurnal heating will promote afternoon
convection across the western sections of Puerto Rico. Ponding of
water in poorly drained areas with the heaviest rain activity is
possible today.

Beachgoers, life-threatening rip currents are likely along the
beaches from Aguadilla to Humacao, Culebra, northern Vieques, and
the north and east coast of St Thomas/St John.

A TUTT-Low lingering east of the Lesser Antilles will enhance the
remnants of an old frontal boundary that the easterly winds will
carry across the U.S. Virgin Islands and Puerto Rico region by
Wednesday. The increase in moisture and local effects will produce
periods of moderate to locally heavy showers, resulting in some
urban flooding. A dry and cool air mass will arrive across the
islands by Wednesday evening, limiting rain activity and promoting
pleasant night temperatures.

&&

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

The latest model guidance suggests a weak frontal boundary on
Friday, with PWAT values fluctuating around 1.15 inches or less.
Despite the expected introduction of moisture, the potential for
the moderate to heavy rainfall activity to develop will be
limited due to the dry air at the mid to upper levels. Expect
winds from the east-northeast to prevail into the weekend as a
surface high continues to build behind the front over the
southwestern Atlantic. Models continue to show a building mid-
level ridge from the west across the Caribbean basing. This
weather feature should provide stable conditions and drier air
intrusion resulting in mostly fair weather conditions across the
islands through at least the beginning of the workweek.

&&

.AVIATION...VFR conditions will persist today. The easterly winds
will sometimes push fragments of clouds and SHRA/-SHRA, affecting
IST/ISX/JSJ briefly. Expect SHRA/-SHRA formation between 21/16-23z
across the western sections, moving near/across JBQ/IST/ISX;
SHRA/-SHRA downwind from El Yunque may also affect JSJ. Winds will
continue calm to light/VRB thru 21/13z, then will return from the
E at 15-20 kt with gusts up to 25-30 kt and sea breeze variations.

&&

.MARINE...Expect a gradual improve in marine conditions today
into tonight. Seas between 4 to 6 feet are forecast across most
of the local waters, with winds up to 20 knots across the
Caribbean exposed waters. A high risk of rip currents will
persist across northern, northeastern, and northwestern Puerto
Rico, as well as Culebra, St. Thomas, and St. John. The risk of
rip current will turn moderate for all the coastal areas on
Wednesday.

&&

.SJU WATCHES/WARNINGS/ADVISORIES...
PR...High Rip Current Risk through late tonight for PRZ001-002-005-
012.

High Rip Current Risk through this afternoon for PRZ008.

VI...High Rip Current Risk through this afternoon for VIZ001.

AM...None.
&&

$$

SHORT TERM...CAM
LONG TERM....MMC
AVIATION...CAM

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
421 AM AST Wed Mar 22 2023

.SYNOPSIS... An increasing in shower activity is forecast for
today as a frontal boundary reaches the islands. Nevertheless,
conditions are expected to dry out by Thursday. Marine conditions
are expected to deteriorate once again by the beginning of the
weekend.

&&

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

Today will be the wettest day of the Short Term period. A surface
high pressure across the Central Atlantic and a frontal boundary
approaching from the northwest of Puerto Rico and the U.S. Virgin
Islands will promote a northeasterly wind flow across the islands
through Friday.

A surge of moisture embedded in the trades will bring Total
Precipitable Water (TPW) between 1.5 and 1.75 inches of water
throughout the day, especially in the afternoon. Therefore, we
expect showery weather across the windward sections of Puerto Rico,
the U.S. Virgin Islands, and the surrounding waters. The afternoon
shower will develop across the interior and southwest quadrant of
PR. The National Blend of Models (NBM) maximum rainfall amounts
suggested values between one and two inches, especially across the
eastern third of Puerto Rico and in the afternoon across the
southwest quadrant of the islands. The NBM 24-hour rainfall amounts
across the U.S. Virgin Islands will possibly range between a few
hundredths to a quarter of an inch, and isolated higher amounts up
to half an inch is also possible downwind from St Thomas. We expect
ponding of water in poorly drained areas and urban stream flooding
with the heaviest and more persistent rainfall activity.

Moisture will rapidly erode as soon as this evening or by Thursday
early morning. Thursday's weather conditions will be mainly a
mixture between sunshine/clear skies and some clouds. The
northeasterly wind flow may aid in the formation of isolated
afternoon convection across the southwest quadrant but without
flooding problems.

The cold front lingering northwest of the region will drift near the
area but remain off over the Atlantic Ocean by Friday. Although
stable weather conditions should dominate the region, we cannot rule
out a few passing showers, especially across the windward sections
and local waters.

Beachgoers, although the risk of rip currents is moderate today,
please exercise caution, especially in the vicinity of groins,
jetties, reefs, and piers, where rip currents may form. The risk of
rip currents will likely increase to high along the Atlantic
Coastline from Thursday onward.

&&

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

An advective pattern is expected to influence the forecast area
during this period. At this time, models continue to suggest a
high pressure from the west across the Caribbean Basin dominating
the mid-levels through at least Tuesday. On Saturday, expect a
mixture of sunny skies and cloudiness from time to time.
Nevertheless, any rainfall activity across Puerto Rico and the
U.S. Virgin Islands will be due to showers embedded within the
trades or local effects. Latest guidance shows PWAT values around
1.20 inches or less. A similar weather pattern will be seen
through the beginning of the workweek. With this in mind, the mid-
level high will maintain hostile conditions from 500 mb to 700 mb,
limiting the potential for moderate to heavy rainfall activity.
As the high pressure prevails, east-northeasterly winds will
prevail at the surface.

Nonetheless, by Tuesday night into Wednesday, the weather conditions
will change. This change is due to an upper-level short wave trough
that will weaken the mid-level high-pressure, allowing more moisture
to filter into the middle levels and slightly surpassing the 700 mb.
With this weakening, the development of moderate rainfall activity
becomes likely. By mid-week, winds will turn more easterly and
become breezy.

&&

.AVIATION...SHRA/-SHRA will move across the region embedded in
the trades. This activity may sometimes move across the local
terminals, creating brief MVFR conditions, especially by mid-
morning into the afternoon (22/15-22z). Mountain obscuration is
also expected today. Showers will slowly diminish after 22/23z
onward, leaving VFR conditions. Winds will continue mainly from
the ENE at 10 kt or less, returning from the NE at around 15-20 kt
with higher gusts and sea breeze variations after 22/13z.

&&

.MARINE...Latest observations from the CARICOOS buoy network show
seas at 3 to 5 feet across the islands, while seas are near 6
feet at the offshore buoy. Choppy seas are expected to continue
across the exposed waters under a northeast 15 to 20 knots wind
flow. However, conditions are expected to remain below small craft
advisory criteria (7 feet) at least until Saturday, when another
northeasterly swell will arrive. For the beaches, the risk of rip
currents is moderate almost everywhere.

&&

.SJU WATCHES/WARNINGS/ADVISORIES...
PR...None.
VI...None.
AM...None.
&&

$$

SHORT TERM...CAM
LONG TERM....MMC
AVIATION...CAM

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
434 AM AST Thu Mar 23 2023

.SYNOPSIS...Overnight, a dry air mass filtered into the area and
it should last through the at least the end of the workweek.
Therefore, no significant rainfall event is anticipated for the
upcoming days, but passing showers at times cannot be ruled out.
Marine conditions are expected to deteriorate by the weekend and
upcoming workweek, due to increasing winds and the arrival of two
small northeasterly swells.

&&

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

We expect sunshine with a few clouds most of the time today due to
below-normal total precipitable water. A few isolated trade wind
showers cannot be ruled out across the windward sections but should
be brief, if any. The southwest quadrant of Puerto Rico can expect
isolated to scattered rain showers during the afternoon but
without significant flooding.

Two surface high pressure, one weakening in the central Atlantic and
another building across the western Atlantic, will maintain a
frontal boundary off to the northwest of Puerto Rico and the U.S.
Virgin Islands till it dissipates by Friday. This pattern will also
promote a northeasterly wind flow and pleasant temperatures across
the islands through Friday. Then, the winds will strengthen and
become more easterly by Saturday due to the subtropical high
pressure.

The advective pattern will prevail across the region Friday and
Saturday. Therefore, expect a mixture of sunshine/clear skies and
clouds. The cold front lingering northwest of the region will drift
near the area, dissipating off the islands over the Atlantic Ocean
by Friday. Although stable weather conditions should dominate the
region, we cannot rule out a few passing showers, especially across
the windward sections and local waters. Another fragment of moisture
embedded in the trades will increase the frequency and intensity of
the rain showers by Saturday.

Beachgoers, the risk of rip currents is high along the Atlantic
Coastline and will likely continue throughout the weekend.

&&

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

Model guidance suggests a high pressure from the west across the
Caribbean basin dominating the mid-levels through at least
Tuesday. On Sunday, expect a mixture of sunny skies and cloudiness
at times. Nevertheless, any rainfall activity across Puerto Rico
and the U.S. Virgin Islands will be due to showers embedded within
the trades or local effects. PWAT models suggest values around an
inch or less. A similar weather pattern will be seen through the
beginning of the workweek. With this in mind, the mid-level high
will maintain hostile conditions from 500 mb to 700 mb, limiting
the potential for moderate to heavy rainfall activity. As the high
pressure prevails, east-to-east-northeast winds will predominate
at the surface.

Nonetheless, by Tuesday night into Wednesday, the weather conditions
will change. This change is due to an upper-level short wave trough
that will weaken the mid-level high-pressure, allowing more moisture
to filter into the middle levels and slightly surpassing the 700 mb
on Wednesday. With this weakening, the development of moderate
rainfall activity becomes likely through Thursday. From mid-week
onwards, winds will turn more easterly and become breezy.

&&

.AVIATION...VFR conditions will prevail. Winds will be mainly from the
NE at less than 10 kts through 23/13z. Winds will return at 15-20
kt with higher gusts and sea breeze variations aft 23/13z. Some
showers will form across SW-PR between 23/16-23z without impacting
terminals.

&&

.MARINE...For the next couple of days, expect seas up to 6 feet
across the region due to moderate to fresh trade winds. During the
weekend winds will pick up and by early Sunday morning a small
long- period northeasterly swell will reach the forecast area.
This swell will persist through the beginning of the workweek,
followed by a second pulse starting mid- week. Therefore, seas
could become hazardous later in the weekend and workweek.

The risk of rip currents is high along the northern coast of
Puerto Rico.

&&

.SJU WATCHES/WARNINGS/ADVISORIES...
PR...High Rip Current Risk through Friday afternoon for PRZ001-002-
005-008.

High Rip Current Risk from this evening through Friday afternoon
for PRZ012.

VI...None.
AM...None.
&&

$$

SHORT TERM...CAM
LONG TERM....MMC
AVIATION...CAM

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
452 AM AST Fri Mar 24 2023

.SYNOPSIS...Today, expect a mixture of sunny skies and cloudiness
at times across the islands. However, afternoon showers are
anticipated across the interior and southwestern Puerto Rico. The
stable weather pattern will change into an unstable one by mid-
week of next week.

&&

.SHORT TERM...TODAY THROUGH SUNDAY...

A slight increase in moisture (but still below normal for today)
will bring some passing clouds with brief light rains across Puerto
Rico, the U.S. Virgin Islands, and surrounding waters. Thus,
pleasant temperatures and a mixture of sunshine and clouds will
dominate local weather. Afternoon showers will affect the interior
and southwest PR but without significant impacts.

A frontal boundary will dissipate off to the north and northwest of
the islands today as a subtropical high pressure builds across the
Western Atlantic. The local pressure gradient will tighten in
response to the subtropical high pressure increasing east to east-
northeast winds Saturday and Sunday.

The advective pattern will promote the arrival of moisture fragments
across the islands throughout the weekend. Therefore, expect a
mixture of sunshine/clear skies and clouds without ruling out a few
passing showers, especially across the windward sections and local
waters. The frequency of the passing rain showers will be higher on
Saturday.

For the Beachgoers, regardless of the fair weather conditions, life-
threatening rip currents will develop along the Atlantic Coastline's
surf zones in Puerto Rico and the U.S. Virgin Islands and will
likely continue throughout the weekend as a long period northerly
swell invade the local waters.

&&

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

At this time, the mid-level high across the Caribbean Basin
continues to be the dominating feature and will continue to be
until Tuesday. The high-pressure system will maintain hostile
conditions from 500 mb to 700 mb, limiting the potential for
moderate to heavy rainfall activity. Therefore, by the beginning
of the workweek, expect a mixture of sunny skies and cloudiness
from time to time. Nevertheless, any rainfall activity across
Puerto Rico and the U.S. Virgin Islands will be due to showers
embedded within the trades or local effects. For the first part
of the workweek, expect a more zonal wind flow.

A short-wave trough will weaken the mid-level ridge by late Tuesday
into Wednesday, changing the weather conditions. This weakening
will allow more moisture to filter into the middle and upper
levels, making the development of moderate and heavy rainfall
likely.

An approaching mid to upper-level trough from the northwest will
increase instability for the second half of the workweek. Currently,
PWAT values fluctuate around an inch or slightly less from
Wednesday to Thursday. However, models suggest a higher increase
by Friday as the trough amplifies over the northwestern Caribbean
from Friday into the weekend. By the end of the workweek, the
precipitable water content will be around 1.30 inches or higher.
The latest models are showing Friday as the best day for organized
convection. Nonetheless, it is too early to determine the impacts
on Puerto Rico and the U.S. Virgin Islands.

&&

.AVIATION....Similar to yesterday, VFR conditions will prevail.
Winds will be mainly from the ENE-NE at less than 10 kts through
24/13z. Winds will return at 15-20 kt with higher gusts and sea
breeze variations aft 24/13z. Some showers will form across SW-PR
between 24/16-23z without impacting terminals.

&&

.MARINE...Moderate to locally fresh trades across the regional
waters will continue to promote choppy marine conditions with seas
up to 6 feet, and occasional higher. Small Craft should exercise
caution over the offshore Atlantic and Caribbean Waters, as well
as over the local passages. Marine conditions will likely further
deteriorate by the weekend due to increasing winds and the arrival
of a small swell from the northeast. A Small Craft Advisory will
be in effect for the offshore Atlantic waters from early Saturday
through at least Monday. A High Risk of Rip Currents is in effect
for the northern, northeastern, northwestern beaches of Puerto
Rico, Culebra, and St. Thomas.

&&

.FIRE WEATHER...Today, expect favorable fire weather conditions
across Puerto Rico specially in the southern sections of the
island were a Fire Weather Warning is in effect. We urge you to
stay updated for any changes in the forecast and please stay aware
of your surroundings.

&&

.SJU WATCHES/WARNINGS/ADVISORIES...
PR...High Rip Current Risk through Sunday afternoon for PRZ001-002-
005-008-012.

Red Flag Warning from 11 AM this morning to 5 PM AST this
afternoon for PRZ014-027.

High Rip Current Risk through Sunday afternoon for PRZ010.

VI...High Rip Current Risk through Sunday afternoon for VIZ001.

AM...Small Craft Advisory from 2 AM Saturday to 2 AM AST Monday for
AMZ711.

&&

$$

SHORT TERM...CAM
LONG TERM....MMC
AVIATION...CAM

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
400 AM AST Sat Mar 25 2023


.SYNOPSIS...
Passing showers will continue to move today across the islands,
leaving wet roads. Any opportunity for rain in the next week will
be solely from small patches of moisture reaching the area at
times. Increasing winds and a small northerly swell will maintain
choppy seas for the next several days.

&&

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

A patch of moisture has pushed over the islands overnight, and is
currently bringing scattered showers to the region, particularly the
local Atlantic waters as well as eastern and northeastern Puerto
Rico, with a few affecting the nearby islands to the east. This
patch will continue westward, affecting the western part of Puerto
Rico later today, which will help support afternoon showers there.
Meanwhile, there is stable air aloft, with ridging through the mid
and upper levels. There is dry air above around 850 hPa, though in
the patch, moisture may reach to around 700 hPa. The stability and
dry air aloft will inhibit significant convective development.

Dry air moves in behind this patch of moisture, with limited shower
activity this evening through tonight. Another patch of moisture is
anticipated during the day on Monday, though weaker than the one
today. Additional moisture may affect the region as well Monday into
Tuesday, but largely remain over the Caribbean waters.

Overall, the best day for rain during the short term period is
today. Even so, rainfall amounts are likely to be limited today,
with generally fair weather for much of the day over the islands.

&&

.LONG TERM...From Tuesday through Sunday...
A mid level ridge will continue to hold across the northeastern
Caribbean through Wednesday. This feature will promote dry air at
the mid levels, and a trade wind cap inversion around 850 mb.
Precipitable water values will be below normal too, staying below
1.0 inch. Any rain that develops in these days will be short-
lived, and associated with small pockets of moisture dragged by
the trade winds. At the surface, a high pressure will migrate
eastward, generating a low level steering flow out of the east at
around 15 knots. Similar weather conditions will persist during
this period with brief interruptions affecting the islands at
times. So far, none of the global models suggest significant
rainfall accumulation.

By the end of the workweek, and upper level trough will approach
the region along with a frontal boundary. As a result, mid-levels
temperatures will cool down to around -9 to -10 degree Celsius,
increasing instability aloft. On the other hand, columnar moisture
is not expected to be too significant, only tapping briefly into
500 mb. Regardless, a modest increase in shower can be anticipated
by the latter part of the workweek and into the weekend.

&&

.AVIATION...
Generally VFR conds expected next 24 hrs across all aerodromes.
Passing SHRA over the waters, esp the local Atlantic waters, pushing
onshore from time to time could affect TJSJ/TIST/TISX through around
25/13Z, but limited operational impacts expected, though gusty winds
poss around SHRA. Afternoon SHRA for interior and W into SW PR;
potential for impacts at TJPS, though MVFR conds unlikely. Winds ENE
12 to 18 kts after sunrise.

&&

.MARINE...
Recent buoy observations indicate that seas has dropped below
small craft advisory criteria across the offshore Atlantic.
However, enhanced winds and a small northerly swell will continue
to create choppy seas of 4 to 6 feet through at least mid week,
and small craft operators are urged to exercise caution.

There is a high rip current risk for the north-facing beaches of
Puerto Rico, Culebra, St. Thomas and St. John.


&&

.FIRE WEATHER...
The risk for fire propagation will be elevate today for the
southern plains of Puerto Rico. The best moisture should remain in
the northern half of the island, while relative humidities should
be low for the south. Winds will pick up as well, reaching 15 to
20 mph and stronger with the gusts at times. Since the soils are
dry due to the lack of rain, grass and forest fires could spread
with ease in these regions.

&&

.SJU WATCHES/WARNINGS/ADVISORIES...
PR...High Rip Current Risk through Monday afternoon for PRZ001-002-
005-008-010-012.

VI...High Rip Current Risk through Monday afternoon for VIZ001.

AM...None.

&&

$$

SHORT TERM...CS
LONG TERM....ERG

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
400 AM AST Sun Mar 26 2023


.SYNOPSIS...
Small patches of moisture may bring some showers at times across
the islands, but in general, fair weather should prevail.
Conditions could become more favorable for showers by the latter
part of the workweek as an upper level trough approaches.
A high rip current risk will remain in place for the north-facing
beaches of all the local islands.

&&

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

Though there is some patchy moisture that will pass over the islands
from time to time, dragged in by the trade winds, overall conditions
are relatively dry. Precipitable water values are forecast to be
below seasonal normals most of the time, reaching near-normal values
within some of the patches of moisture. Overall, generally fair
weather is expected through the short term period, though a typical
shower pattern will be sustained by what moisture is available,
combined with local effects and daytime heating.

&&

.LONG TERM...from Wednesday through Monday...
The northeastern Caribbean will remain dominated by a mid level
ridge through Wednesday, promoting a trade wind cap inversion and
stable conditions across the area. The ridge will weaken, however,
in response to an upper level trough exiting the eastern coast of
the United States. By the latter part of the workweek, the
environment is expected to become more favorable for shower
production. First, the trough will increase instability aloft as
temperatures at 500 mb cool down to around -8 to -9 degree
Celsius. Second, a surface high pressure will maintain brisk
trade winds across the area, with a low level steering flow around
16 knots. The winds will carry patches of enhanced moisture over
the islands at times. In the most recent model runs, the
healthier patch appears to arrive on Friday, with columnar
moisture tapping into the upper levels of the atmosphere. These
enhanced levels of moisture are expected to result in increasing
shower activity...in the morning mainly for the Virgin Islands
and eastern Puerto Rico, and heavier activity developing in the
afternoon across interior and western Puerto Rico. The showers
early in the day could lead to wet roads and ponding of water in
low-lying areas, while the afternoon activity may lead to urban
and small stream flooding. It is worth noticing that this forecast
will be dependent on the timing of both the upper level trough
and the area of enhanced moisture, so adjustments may be needed
later in the week.

For Saturday, the upper level trough remains, but precipitable
water values drop down from 1.7 inches on Friday to 1.04 on
Saturday. Showers are still expected in the afternoon for western
Puerto Rico, but with less accumulation in the forecast. For
Sunday and Monday, the islands will no longer be under the
influence of the upper level trough, but fluctuations in the
amount of available moisture at the lower levels may still trigger
a few showers. For now, Monday appears to be the driest day in the
period.




&&

.AVIATION...

Generally VFR conds expected next 24 hours for all aerodromes.
Passing SHRA, mostly over the waters, are unlikely to have
operational impacts at terminals. Isol'd to sct SHRA this afternoon
for interior and W PR, likely remaining N of TJPS and S of TJBQ.
Terrain obscurations possible. Winds increase out of E/ENE after
sunrise to around 12 to 18 kts, with sea breeze variations and
stronger gusts. Winds diminish after sunset.

&&

.MARINE...
The most recent Gerling-Hanson plot analysis (for buoy 41015)
indicates at least two notable wave systems that will reach the
Atlantic waters today. A long-period (15 seconds), but small
northerly swell (2-3 feet) will arrive in combination with another
group of waves of about 5-6 feet. The significant wave height
however, should remain below 7 feet, so small craft advisories
will not be needed at this time.

The risk of rip currents will be high for all of the north-facing
beaches of Puerto Rico, Vieques, Culebra and for all of the U.S.
Virgin Islands.

.FIRE...
A drier air mass will be filtering along the islands today. This
should lead to relative humidities dropping into the low 40s for
most of the southern plains of Puerto Rico. Due to the lack of wet
rains in the past days, the moderate trade winds and low RH
values, the risk for fire spreading will remain elevated.


&&

.SJU WATCHES/WARNINGS/ADVISORIES...
PR...High Rip Current Risk through Tuesday afternoon for PRZ001-002-
005-008-010-012.

High Rip Current Risk through Monday afternoon for PRZ013.

VI...High Rip Current Risk through Tuesday afternoon for VIZ001.

High Rip Current Risk through Tuesday afternoon for VIZ002.

AM...None.

&&

$$

SHORT TERM...CS
LONG TERM....ERG

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
445 AM AST Mon Mar 27 2023

.SYNOPSIS...

Generally fair weather is expected to prevail through much of this
week. There is the potential for a modest increase in shower
activity at the end of the week, but uncertainty is high. Seas of up
to 6 feet are expected across the waters, with a high risk of rip
currents for many local beaches.

&&

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

A mid level ridge will continue to hold north of the islands,
creating a trade wind cap inversion around 850 mb and a dry air mass
above this level. At the surface, a surface high pressure will
maintain the trade winds enhanced, out of the east or east-southeast
at around 15 knots. The mid-level ridge will maintain all the
moisture trapped at the lower levels of the atmosphere, while
preventing the development of significant shower activity. Total
Precipitable Water from GOES-16 also indicates a dry air mass
covering the northeastern Caribbean, with a small pocket of slightly
higher moisture content moving over the Atlantic waters and into the
islands. As this patch of moisture goes through, it may trigger a
shower or two, but again, with the lack of support at the mid and
upper levels, rainfall accumulation should be light. A similar
pattern is expected to continue for the next several days, still
under the influence of a ridge and the trade winds carrying small
patches of moisture at times.

&&

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

Overall, generally fair weather is expected through the long term
period. Patches of moisture, including the fragmented remains of an
old, decayed frontal boundary on Friday into Saturday, will affect
the region from time to time. This will support shower activity,
though dry air between moisture patches will maintain relatively
calm conditions overall.

One significant change in the forecast is for this weekend. Model
guidance remains on the fence for what we will see this weekend.
There is still an upper-level trough that is likely to affect the
region late on Friday; it is forecast to deepen while west of the
islands and then sweep across the area Friday night into Saturday.
However, there is much less certainty that there will be much in the
way of moisture for any enhanced instability to work with. Model
guidance now suggests that much of the best moisture with the
aforementioned frontal fragments will stay south of the islands,
inhibiting any increase in shower activity. As such, the forecast
reflects a decreased potential for rain Friday into Saturday. Even
so, this is more a reflection of uncertainty that rain will occur
than a certainty that it will not occur. It cannot be ruled out that
significant moisture will affect the area.

Beyond this weekend, patches of moisture will continue, but decrease
in magnitude. Still, within the moisture patches, precipitable water
values are forecast to be near seasonal normals. Relatively dry
conditions are currently anticipated for the start of the next
workweek.

&&

.AVIATION...
(06Z TAFS)

VFR conditions expected to prevail. Limited SHRA
activity expected this afternoon across the interior and western PR,
with mountain obscuration possible. Winds will pick after 13-14Z,
mainly out of the east at 15-18 kts, gusting up to around 24kts.
Winds will slow down after 22Z, mainly below 10 knots.

&&

.MARINE...

A northeasterly swell is affecting the local waters, with period on
the order of 14 to 16 seconds. However, this swell is fairly small,
and wind waves make up a good portion of the energy, and may even be
the dominant source of waves at times. The swell itself is only
about 2 feet high. With winds becoming more easterly today, some
confused seas are possible in portions of the waters that are
exposed to the north. Winds of up to 15 to 20 knots will maintain
some choppy conditions across the waters, except in areas sheltered
to the east. Breaking waves of up to around 9 feet are expected for
north-facing beaches.

There remains a high risk of rip currents for beaches of Culebra,
the USVI, and northern Puerto Rico from Rincon to Fajardo.

&&

.FIRE WEATHER...

Critical fire weather conditions were observed in the southern
coastal plains of Puerto Rico yesterday. Soils and fuels are dry,
and wetting rains are unlikely for the area over the next several
days. This will continue to exacerbate conditions there.
Additionally, winds of up to 15 to 20 mph are possible,
particularly in sea breezes, with stronger gusts likely. RH values
will fall into the 40s and possibly 30s today. The potential for
fires, once ignited, to spread is quite high. Red Flag conditions
cannot be ruled out again today.

&&

.SJU WATCHES/WARNINGS/ADVISORIES...
PR...High Rip Current Risk through late Tuesday night for PRZ001-002-
005-008-012.

High Rip Current Risk through Tuesday afternoon for PRZ010.

VI...High Rip Current Risk through late Tuesday night for VIZ001.

High Rip Current Risk through this afternoon for VIZ002.

AM...None.
&&

$$

SHORT TERM...ERG
LONG TERM....CRS
AVIATION...ERG

[cycloneye]

The annual visit to Puerto Rico of the hurricane hunters will be on April 22nd in Aguadilla, a town located in the northwest.

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
439 AM AST Tue Mar 28 2023

.SYNOPSIS...

Generally fair weather is expected through the weekend, though with
patchy moisture supporting some shower activity. Passing showers are
anticipated in the east and northeast during the overnight hours and
in the mornings, with afternoon showers possible in western and
interior portions of Puerto Rico. There remains a high risk of rip
currents for much of the local beaches.

&&

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

A surface high pressure will maintain east trade winds through
Wednesday. The high will maintain the gradient tight today, with the
winds at around 15 knots. Then, the high will migrate westward,
while weakening, causing the general steering flow to slow down a
little. Small patches of moisture embedded in the winds will reach
the islands at times, bringing brief interruptions of showers for
sections of eastern Puerto Rico and the U.S. Virgin Islands. Moving
upward in the atmosphere, a mid level ridge holds, promoting a trade
wind cap inversion at 4,000 feet. With the available moisture
provided by the patches of moisture, some showers may develop in the
afternoon across western Puerto Rico, but due to unfavorable
conditions aloft, these showers are not expected to leave
significant rainfall accumulation.

By mid-week, the mid level ridge will begin to flatten out, as a
trough exists the eastern coast of the United States. This will
gradually weakens the trade wind cap inversion, allowing for a
slightly more favorable conditions for showers development. At the
same time, a wider patch of moisture will approach the northeastern
Caribbean, causing a few more showers to affect eastern Puerto Rico
and the Virgin Islands. In the afternoon, aided by the local
effects, moderate showers should develop over the west. On Thursday,
a similar pattern is anticipated, but with a little more moisture
available, rainfall accumulations could be higher for the afternoon
activity over western Puerto Rico. Wet roads and ponding of water in
areas with poor drainage should be the main concern with these
rains.

&&

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

Not much change to the forecast. Through Monday into Tuesday, at
least, patchy moisture will be the dominant feature, sustaining
shower activity in a typical pattern. An upper-level low is expected
to provide an increase in instability late on Friday into Saturday,
but limited moisture will result in only a modest increase in shower
activity. At the mid-levels, a ridge is expected to maintain its
hold over the area at least into the next workweek. Currently, the
best-looking patch of moisture is forecast for Sunday, but certainty
is fairly low.

Model guidance suggests a change in our rather persistent dry
pattern is possible for Tuesday into Wednesday next week. Both the
GFS and the Euro suggest that a deep-layer trough will strengthen
over the Atlantic, bringing instability to the region. There is also
the potential that the fragmented remnants of an old frontal
boundary will push up to meet the moisture from a frontal boundary
to the north, bringing moisture. That being said, there is also a
hint that there will be a dry slot in the vicinity of the islands.
All in all, there are many features at play here, and forecast
confidence is really quite low. It is also fairly likely that the
models are overly zealous with how far south the frontal boundary
will reach. If that proves a correct assessment, though, it could
result in a few potential scenarios - including one in which there
is dry air persisting over the area, with the fragments of the old
frontal boundary remaining mostly to the south - much as the best
moisture is forecast to do through the preceding days. That being
said, it could also allow for a slightly further trajectory of those
fragments of moisture. On the whole, with low certainty of any
particular scenario, the forecast is a slightly modified version of
climatology, and adjustments are very likely to be introduced in
future forecasts.

Overall, there is decent confidence that the overall pattern will
remain dry through Monday, with patchy moisture providing support to
some shower activity, with uncertainty on timing and location of the
showers. All activity will likely be in a typical pattern, however.
Beyond that, however... 'Outlook uncertain. Ask again later' is
probably the best description. There is a nonzero chance we get a
break in this seemingly relentless dry pattern, though, which is
some small optimism to leave you with.

&&

.AVIATION...
(06Z TAFS)

VFR conditions expected to prevail through the forecast period.
Few SHRA will move at times around the local waters, but with
little to no impact to operations. Winds will pick up after 13-
14Z, coming out out the east at E at ENE at 14-18 kts, with
stronger gusts. Winds will slow down after 22Z, below 10 knots.

&&

.MARINE...

There remains a north-northeasterly swell affecting the waters; it
is a small swell, though, with a height of around 2 feet, though the
period is long, around 14 to 17 seconds. Combined seas of around 4
to 6 feet are expected, with choppy conditions maintained by winds
of around 15 to 20 knots out of the east. Operators of small craft
should exercise caution.

There remains a high risk of rip currents for beaches of the USVI,
Culebra, and northern Puerto Rico, from Rincon to Fajardo.

&&

.SJU WATCHES/WARNINGS/ADVISORIES...
PR...High Rip Current Risk through Wednesday afternoon for PRZ001-002-
005-008-010-012.

VI...High Rip Current Risk through Wednesday afternoon for VIZ001-002.

AM...None.
&&

$$

SHORT TERM...ERG
LONG TERM....CRS
AVIATION...ERG

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
448 AM AST Wed Mar 29 2023


.SYNOPSIS...

A patch of moisture is affecting the area and has brought a
marked increase in shower activity compared to previous nights. A
typical shower pattern is expected to prevail, with showers
supported by patchy moisture that will continue to affect the
region from time to time through the weekend and into next week.
There remains a high risk for many local beaches, as well; with
seas of up to 6 feet anticipated for the local waters, operators
of small craft should exercise caution.

&&

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

Shallow patches of moisture will continue to move in through the
islands through Thursday. At the mid levels, a ridge is weakening,
with the trade wind cap inversion moving up to around 8000 feet
(750 mb). This will allow for a little deeper moisture in the
column today and also on Thursday, which will lead to increased
showers. These showers will move across eastern Puerto Rico and
the U.S. Virgin Islands early in the day. In the afternoon, local
effects will trigger additional activity in the west, with ponding
of water on roadways and low lying areas possible. For eastern
Puerto Rico and the U.S. Virgin Islands, the activity should
decrease later in the day today. By tomorrow, better moisture
content is anticipated, with precipitable water values climbing to
around 1.4 inches. The frequency of showers should increase as
well, with a greater areal coverage across the interior and west
during the afternoon hours.

On Friday, a surface high pressure will roll eastward from the
southeastern coast of the united States. This feature will drive
trade winds out of the east northeast with speeds increasing to
around 18 to 20 knots. At the upper level, a trough will approach,
increasing instability aloft. On the other hand, the low levels will
dry out as precipitable water values drops to around 0.7 inches,
which is below the climatological value for this time of the year.
Even with better support at the upper levels, the lack of moisture
should cause the shower activity to be focused along the west
southwest of Puerto Rico during the afternoon hours.

&&

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

Not much change to the forecast. Through Monday into Tuesday, at
least, patchy moisture will be the dominant feature, sustaining
shower activity in a typical pattern. At the mid-levels, a ridge is
expected to maintain its hold over the area at least into the next
workweek. Currently, the best-looking patch of moisture is forecast
for late Sunday into Monday, but certainty is fairly low in terms of
timing and location of moisture patches, and this is subject to
change, much as it already has a couple of times now.

Model guidance suggests a change in our rather persistent dry
pattern is possible for Tuesday into Wednesday next week. Model
guidance has sped up the progression of the upper-level trough
associated with a low over the central/northern Atlantic, bringing
the best instability for Tuesday more than Wednesday. It has also
decreased the amount of instability anticipated with this feature
over the region. Additional changes have been seen in the moisture
pattern over the area, though the impacts of multiple fragments of
moisture resulting from the remains of multiple decayed frontal
boundaries are still reflected in the model solutions, as is the
potential for interaction with a frontal boundary approaching from
the north around the same time. On the whole, forecast confidence is
low from Tuesday onward, and so the forecast remains a lightly
modified climatology. Considering the model trend, and what the
model has done in previous weeks with being somewhat overzealous
with upper-level troughs and frontal boundaries and then backing off
as lead time decreases, this is a more likely situation on the
whole. At the moment, this looks like it has the potential still to
provide some much-needed relief from the dry conditions that have
been pervasive over the last several weeks. That being said, it's
also possible that this is all much ado about nothing, and only a
modest uptick in shower activity may occur, if that. Only time will
tell.

&&

.AVIATION...
(06Z TAFS)

Mainly VFR conditions expected to prevail. SHRA are expected to move
in across most of the terminals except TJBQ, with brief periods of
reduced VIS and low ceilings possible. Additional activity expected
for the western Cordillera Central after 17Z, with mountain
obscuration possible. Winds will be out of the E or ESE at 10-13
kts, with stronger gusts.

&&

.MARINE...

There remains a fading northeasterly swell within the local Atlantic
waters and passages. Meanwhile, easterly winds at around 10 to 20
knots will maintain choppy conditions across the waters. Seas of up
to 6 feet are possible, mostly for the Atlantic waters and Anegada
Passage, with seas of up to 5 feet elsewhere. There remains a high
risk of rip currents through at least tonight for the beaches of the
USVI (particularly northwestern St. Thomas and eastern St. Croix),
Culebra, and northern Puerto Rico from Aguadilla to Fajardo.

&&

.SJU WATCHES/WARNINGS/ADVISORIES...
PR...High Rip Current Risk through late tonight for PRZ001-002-005-
008-012.

High Rip Current Risk until 6 AM AST early this morning for
PRZ010.

VI...High Rip Current Risk through late tonight for VIZ001-002.

AM...None.
&&

$$

SHORT TERM...ERG
LONG TERM....CRS
AVIATION...ERG

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
435 AM AST Thu Mar 30 2023

.SYNOPSIS...Rounds of passing scattered showers will affect the
region today as shallow moisture filters in. This activity will
likely spread mainly over interior and northwestern Puerto Rico in
the afternoon. Less shower activity, stronger winds and drier air
are expected tomorrow and into the weekend. There is a High Rip
Current Risk today for the north- and east-facing beaches of
Puerto Rico, as well as for Culebra and St Croix.

&&

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

High pressure exiting the Eastern U.S. will move slowly eastward
across the Western Atlantic over the next few days. This surface
high pressure promotes east to northeast winds across the local
region. Winds become stronger at around 20 knots from Friday into
the weekend. These fresh trade winds will push fragments of low-
level clouds and scattered showers across the U.S. Virgin Islands
and Puerto Rico from time to time. For today, satellite-derived
precipitable water analysis suggests that moisture will increase by
around 1.25 inches. However, these showers will be shallow as the
700 mb - 500 mb high pressure will keep dry and relatively stable
conditions aloft. High-resolution models suggest that the first
round of scattered showers will affect portions of the U.S. Virgin
Islands, Culebra, Vieques, and eastern Puerto Rico around mid-
morning. Then, scattered showers will likely spread over the
interior and northwestern Puerto Rico early in the afternoon. Rain
accumulations will range between a few tenths of an inch in eastern
PR and half an inch to an inch over the interior and northwest
Puerto Rico.

A strong trade wind cap will trap the moisture below 850 mb Friday
and Saturday. Also, a dry and stable air mass will move over the
local islands under a fresh northeast flow. Rainfall probabilities
are very low for Friday and Saturday as precipitable water values
plunge below 0.8 inches, way below normal for this time of the year.
Although an upper-level trough develops over Puerto Rico early in
the weekend, the high pressure at the mid-level will dominate the
weather conditions keeping the local area under fair weather.

&&

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

By Sunday and into the next workweek intervals of patches of
moisture and dry air will filter into the region, promoting passing
shower activity across windward sectors of the islands. Overall
moisture will continue to be a limiting factor in shower activity at
this time. Model guidance has varied in the timing of the patches of
moisture but shows an overall increase by Wednesday and Thursday,
with precipitable water (PWAT) values at to slightly above normal
values. In the upper levels, the long term period is forecast to
start with an upper level trough gradually exiting the region,
promoting gradually increasing stability. Current model guidance
seems aggressive in developing an upper-level trough over the region
by early Wednesday, this feature would continue to affect the
islands through the end of the short term forecast period. To start
next week, moisture will be limited to the lower levels with mid
level ridging persisting, but current model guidance indicates that
available moisture will reach the mid to upper levels by Wednesday
and Thursday. At surface level, a high pressure system will be over
the central Atlantic to start the week and another high pressure
will move into the western Atlantic to end the forecast period.
Winds start off next week being generally easterly, before becoming
more northeasterly by midweek. For early next week shower activity
will be mostly dependent on those patches of shallow moisture,
reaching near normal PWAT values, embedded in the trade wind flow
and reaching windward sectors during the evening and morning hours.
Limited afternoon convection, due to diurnal and local effects, is
possible mainly over western/southwestern Puerto Rico. As moisture
and instability will possibly increase by midweek, shower activity
could increase, with stronger showers and afternoon convection. This
possible development will continue to be monitored.

&&

.AVIATION...Mostly VFR conditions expected to prevail across most
of the TAF sites. VCSH expected to move in across USVI terminals
thru 15Z, then SRHA will develop in and around TJBQ between
18Z-21Z. Brief periods MVFR ceilings and mountain obscuration
possible. Winds will be out of the E around 15 kts, with stronger
gusts.

&&

.MARINE...A surface high pressure stretched across the Atlantic
Basin will continue to promote moderate to locally fresh trade
winds across the regional waters, resulting in choppy seas up to 5
ft, mainly over Atlantic waters and the local passages. A
subsiding northeasterly swell will continue to affect the local
Atlantic waters and passages. Winds will up to around 15 knots,
locally higher, particularly across nearshore northern waters of
Puerto Rico where Small Craft Should Exercise Caution. Marine
conditions will deteriorate by Friday night into the weekend due
to strong winds. There is a High Rip Current Risk for the north
and east- facing beaches of Puerto Rico, as well as for Culebra,
St Thomas, St John and St Croix. St. Thomas and St. John, however
will have only up to a moderate risk of rip currents by 6 AM AST.

&&

.SJU WATCHES/WARNINGS/ADVISORIES...
PR...High Rip Current Risk through late Friday night for PRZ001-002-
005-008-012.

VI...High Rip Current Risk until 6 AM AST early this morning for
VIZ001.

High Rip Current Risk through this afternoon for VIZ002.

AM...None.

&&

$$

SHORT TERM...ER
LONG TERM....MRR

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
456 AM AST Fri Mar 31 2023

.SYNOPSIS...Breezy and mostly dry and stable conditions will
likely prevail through tomorrow across the local islands as a
drier air mass filters into the region. An upper level trough will
move across the region during the next couple of days but it will
have minimal impacts as mid-level ridging continues. Today's
hazards include elevated to critical fire weather conditions as
well as deteriorating marine and coastal conditions.

&&

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

Surface high pressure over the western North Atlantic will dominate
the local weather conditions in the short term. This feature will
reinforce the trade winds across the northeast Caribbean region
through at least the weekend while providing a generally fair
weather pattern today and Saturday. At upper levels, a short-wave
trough will move eastward over Puerto Rico during the next 24-48
hours, but its impact on the local weather conditions will be
minimal as the 700 mb high pressure will keep a foothold on the
region.

In terms of moisture, precipitable water values will remain below
normal through Saturday, reaching a minimum of 0.7 inches this
afternoon. Moisture will return to normal levels on Sunday when
fragments of low-level moisture move near or over Puerto Rico and
the U.S. Virgin Islands.

In summary, Breezy and generally dry and stable conditions will
likely prevail through Saturday across the local islands. On Sunday,
scattered showers embedded in the fresh to strong trade winds will
bring variable conditions. However, the fast movement of those
showers will limit the rainfall accumulation over the U.S. Virgin
Islands and Puerto Rico.

&&

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

No significant changes to the long term forecast. The workweek will
start with intervals of patches of moisture and dry air filtering
into the region, promoting passing shower activity across windward
sectors of the islands. Model guidance continues to vary on the
timing of the moisture patches but shows an overall increase by mid
week and by the end of the workweek, with precipitable water (PWAT)
values at to slightly above normal values. At surface level, a high
pressure system will be over the central Atlantic to start the
workweek and another high pressure will move into the western
Atlantic to end the forecast period. Winds start off next week being
generally easterly, before becoming more northeasterly by midweek
and more southeasterly by the end of the week. In the upper levels,
the long term period is forecast to start with an upper level trough
moving east the region. To start next week, moisture will be limited
to the lower levels with mid level ridging persisting, but current
model guidance indicates that available moisture will reach the mid
to upper levels by Wednesday and Thursday. This is due to an upper-
level trough, that current model guidance is suggesting, affecting
the region through the second part of the workweek. To start the
workweek shower activity will mostly depend on patches of shallow
moisture, reaching near normal PWAT values, embedded in the trade
wind flow and reaching windward sectors mainly during the evening
and morning hours. Limited afternoon convection, due to diurnal and
local effects, is possible mainly over sectors of western Puerto
Rico. As moisture and instability will possibly increase by midweek,
promoting stronger shower activity.

&&

.AVIATION...VFR conditions expected to prevail across most of the
TAF sites. Mostly cloudy skies in the morning, then sunny to
partly cloudy in the late morning and afternoon. SHRA, if any,
will develop between TJMZ and TJPS. Not operational impacts are
anticipated through the forecast period. VCSH possible at TJSJ
tonight. ENE Winds around 15- 20 kt increasing to around 20 kt
during the weekend. Occasional wind gusts around 25-30 at times.

&&

.MARINE...Moderate to locally fresh trade winds across the
regional waters are resulting in choppy conditions. A small
northeasterly swell will continue to affect the local Atlantic
waters and passages. Small craft should exercise over most local
waters due to seas up to 6 ft and/or increasing winds. Due to
increasing winds, marine conditions will deteriorate by tonight
and into the weekend. Small Craft Advisories will be in effect
starting this evening across most of the local waters. For today
and tonight, a high risk of rip currents will be in effect for the
north oriented of Puerto Rico, as well as for beaches of Culebra
and the northern USVI. Tonight the high risk of rip currents
extends to the eastern beaches of St. Croix and to the beaches of
Aguada and Rincon.

&&

.FIRE WEATHER...Dry air and breezy conditions will promote
elevated to critical fire weather conditions during the late
morning and into the late afternoon. Therefore, a Red Flag
Warning was issued for the southern coastal plains of Puerto Rico.
Additionally, a Fire Danger Statement was issued for the southern
hills, west coast, northern hills, and central mountain range of
Puerto Rico. For more information, please refer to the Red Flag
Warning (RFWSJU), Fire Danger Statement (RFDSJU) and Fire Weather
Planning Forecast (FWFSJU) products.

&&

.SJU WATCHES/WARNINGS/ADVISORIES...
PR...High Rip Current Risk through late Sunday night for PRZ001-002-
005-008-012.

Red Flag Warning from 11 AM this morning to 5 PM AST this
afternoon for PRZ014-027.

High Rip Current Risk from this evening through late Sunday
night for PRZ010.

VI...High Rip Current Risk from this evening through late Sunday
night for VIZ002.

High Rip Current Risk through late Sunday night for VIZ001.

AM...Small Craft Advisory from 8 PM this evening to 8 AM AST Monday
for AMZ711-723-741.

Small Craft Advisory from 8 AM Saturday to 8 AM AST Monday for
AMZ712.

Small Craft Advisory from 2 AM Saturday to 8 AM AST Monday for
AMZ716.

Small Craft Advisory from 8 PM this evening to 8 AM AST Sunday
for AMZ733.

&&

$$

SHORT TERM...ER
LONG TERM....MRR

[cycloneye]

.PREV DISCUSSION... /issued 442 AM AST Sun Apr 2 2023/

SYNOPSIS...Brisk trade winds will continue to push a few clouds
and light showers across the local islands through midweek. Moisture
is below normal therefore little or no rainfall accumulation are
expected with the morning showers. Measurable rainfall is likely
each afternoon across western Puerto Rico. A wetter and more
unstable pattern is forecast the second half of the week as a deep
upper level trough develops over Puerto Rico and the U.S. Virgin
Islands. Marine and coastal conditions will remain hazardous over
the next couple of days.

SHORT TERM...Tonight through Tuesday...

Intervals of dry and humid patches of air will continue affecting
the islands through the short term forecast period. Current
satellite precipitable water (PWAT) indicate a patch of moisture
with values up to around 1.3 inches moving across the region with
other dry or less humid patches behind it. At the upper-levels, a
trough is moving across the islands, gradually exiting the area.
Impacts from this feature however, will continue to be minimal due
to ridging at around 700 mb. Any available moisture will be mostly
restricted to below 700 mb to start the workweek. At surface level,
a high pressure system over the Atlantic continues to spread
eastward and promoting breezy conditions with for most of the
period. Breezy conditions will also aid in limiting rainfall
accumulations over the islands as showers will be fast moving. Most
shower activity during the short term period will depend on those
patches of moisture embedded in the trade winds reaching our area
and bringing associated passing showers. PWAT values should overall
reach near or below normal levels today, promoting more variable
conditions; current model guidance indicates a decrease in PWAT to
below normal levels tomorrow morning, making it possibly the
driest day in the short term period, and a gradual increase in
PWAT on Tuesday. Shower activity, including isolated to scattered
showers over windward sectors during the morning and evening and
afternoon convection over western Puerto Rico due to local effects
and diurnal heating, will increase when those patches of
moisture, fragments of old frontal boundaries, are affecting the
area and decrease to cease when drier air filters in.

LONG TERM...Wednesday through Sunday...

Unstable weather conditions are forecast for the second part of
next week as a deep layer low develops over the northeast Caribbean
region. Both models, GFS and ECMWF, have been consistent with the
location and intensity of the upper trough near the local area
late in the week. Also, 500 mb temperature and geopotential height
anomalies are significantly lower for our area if it's compared
with our sounding climatology. Therefore, high instability and
enhanced risk of heavy rain will be associated with this potent
mid-upper level low. Very cold temperatures at mid- levels will
enhance the potential of thunderstorms across the region,
especially Thursday and Friday. The peak of instability and
organized convection should occur between Thursday and Friday when
the trough/low deepens over Puerto Rico and the U.S. Virgin
Islands. The ECMWF EFI continues to suggest organized convection
associated with this trough/low. The highest signal is over the
U.S. Virgin Islands and the Caribbean waters south of Puerto Rico.
If the model verifies, the U.S. Virgin Islands, Culebra, Vieques
and eastern Puerto Rico will likely experience the brunt of the
shower and thunderstorm activity. During the weekend, operational
models are showing that the trough will weaken as it lifts
northward into the western Atlantic. As a result, conditions will
likely improve Saturday and Sunday as moisture and instability
will gradually decrease across the local islands.

AVIATION...Overall VFR conditions will continue across the
terminals, brief MVFR conditions possible due to passing shower
activity across mainly TJSJ/TISX/TIST during the early morning
hours. Wind flow will be generally easterly to ESE at around 15-25
kts, with higher gusts and sea breeze variations. Afternoon
convective activity could also promote brief MVFR conditions at TJBQ
during the afternoon afternoon hours.

MARINE...Fresh trade winds continue across the regional waters
resulting in choppy conditions. Wind-driven seas and a small
north-northeast swell are producing hazardous seas of 5-7 feet
across the local Atlantic waters and Caribbean Passages. These
hazardous marine conditions will continue over the next couple of
days. Small Craft Advisories are in effect for most of the local
waters though the morning hours, however some of the zones such as
the offshore Atlantic waters and Anegada Passage continues
through at least Monday afternoon. The high risk of rip currents
will continue for the Atlantic beaches of most the islands.

FIRE WEATHER...Breezy conditions and a relatively dry air mass
will lead to elevated fire weather conditions across portions of
the islands once again today. As a result, a Fire Danger Statement
was issued for the southern coastal plains of Puerto Rico. For
more information, please refer to the Fire Danger Statement
(RFDSJU) and Fire Weather Planning Forecast (FWFSJU) products.

&&

.SJU WATCHES/WARNINGS/ADVISORIES...
PR...High Rip Current Risk through Monday afternoon for PRZ001-002-
005-008-012.

High Rip Current Risk through late tonight for PRZ010-013.

VI...High Rip Current Risk through Monday afternoon for VIZ001.

High Rip Current Risk through late tonight for VIZ002.

AM...Small Craft Advisory until 2 PM AST Monday for AMZ711-723.

&&

$$

DSR/GRS