Caribbean - Central America Weather

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
514 AM AST Thu Feb 23 2023

.SYNOPSIS...An area of low-level cloudiness with light showers
will continue to move over the islands today. A mid-level ridge
will remain in place, promoting drier air aloft and overall stable
conditions. Moisture increases briefly once again on Saturday due
to the remnants of an old frontal boundary. Breezy northeast
trades will prevail during the next several days.


&&

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

Forecast continues on track with a mid-level ridge persisting
through the short-term period supporting an inversion cap close to
the 850 mb layer with dry air and stable conditions above. At low-
levels, a surface high pressure over northwestern Atlantic and a low
pressure across central Atlantic is tightening the pressure gradient
across the northeastern Caribbean promoting breezy east northeast
wind conditions. As this pattern continues to evolve, bands of
clouds are being dragged by the northeasterly trades as observed in
satellite imagery. These bands of clouds are bringing isolated to
scattered showers across northern and eastern portions of the
islands, especially to St. Thomas and St. John. This pattern is
expected to continue for the rest of today and also tomorrow, with
an enhancement of showers across southwest portions of Puerto Rico
each afternoon. Significant rainfall accumulations is unlikely.

On Saturday, the northeasterly trades will push the remnants of a
frontal boundary from the north Atlantic into the forecast area
promoting showery weather throughout the day over roughly the same
areas than in previous days. Saturday will be the wettest day of the
short-term period. However, breezy conditions will make any shower
development to be fast-moving minimizing rainfall accumulations in
areas with the heaviest showers.

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

A mid-level ridge over the Caribbean basing will promote a drying
trend through the long-term period across the islands. Precipitable
water content is expected to drop below 1 inch on Sunday, and
fluctuate between 0.80-1.20 inches each day. The higher values are
expected across the USVI with the nighttime/early morning shallow
convection. However, minor rainfall accumulations are expected
with this activity. Across PR, drier conditions are expected in
general, with a slight increase in shower activity by midweek as
a short-wave trough moves over the region. Weakening of the
surface ridge over the southwestern Atlantic is expected by
Tuesday onwards. In response, the trade winds will relax somewhat
and turn more from the east to east-southeast.


&&

.AVIATION...Mainly VFR conditions are expected to prevail across all
terminals during the next 24 hours. A broad patch of low to mid
level clouds may briefly create SCT-BKN ceilings at FL025-FL050 with
isolated SHRA over the regional waters causing brief MVFR, but with
limited operational impacts at terminals during period. Low-level
winds will continue from the E-NE at 10 to 15 kts, increasing to 15-
20 kts with occasional higher gusts after 23/14Z.


&&

.MARINE...Moderate to fresh trade winds (15-20 kt) will continue
across most of the local waters, and small craft should exercise
caution. Seas will range between 3 and 5 feet. A moderate risk of
rip currents continues for the north and east facing beaches of
the islands.


&&

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

$$

SHORT TERM/AVIATION...CVB
LONG TERM/MARINE...DSR

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
507 AM AST Fri Feb 24 2023

.SYNOPSIS...Drier conditions compared to yesterday are expected
today across the islands. The remnants of an front will move
across the region from late tonight and through Saturday. A mid-
level ridge will support overall fair weather conditions through
the rest of the period. However, shallow moisture content will
reach the islands from time to time and bring occasional showers
during the night and early morning hours.


&&

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

Latest Doppler radar is detecting isolated trade wind showers
affecting northern and eastern portions of the islands with a few
reaching interior sections of Puerto Rico. Satellite imagery also
shows the potential of patchy fog affecting higher elevations and
valleys in Puerto Rico. A band of clouds is also promoting isolated
showers extending from the south of Puerto Rico, over the Caribbean
waters, to the northeast towards St. Croix. These showers, however,
are leaving minimal rainfall accumulations. This pattern will
continue into the morning hours with patchy fog persisting across
the mountainous areas of Puerto Rico. Be extra cautious if driving
interior areas as patchy fog could cause sudden changes in
visibility.

Dynamically speaking, the mid-level ridge will hold for the rest of
the forecast period. The trade wind cap will shift between the 850
mb and 750 mb layer throughout the period, but with dry stable air
aloft which will continue to hinder deep convective activity. At low-
levels, sharp moisture gradients will cause varying precipitable
water (PWAT) values producing varying weather conditions. This
afternoon, although below normal moisture content is expected, local
effects and sea breeze convergence could enhance shower activity
over the southwestern quadrant of Puerto Rico.

By late tonight and early Saturday morning, the northeasterly trades
will push the remnants of a frontal boundary into the area with
bands of clouds and showers crossing the islands throughout the day.
This will increase PWAT values between 1.4 and 1.5 inches across the
islands, which is near normal to slightly above normal the
climatological levels. Expect cloudy skies and showery weather
affecting the northern and eastern portions of the islands,
especially northeastern Puerto Rico and northern USVI during the
morning hours. Showers will gradually move southward throughout the
day as the fragmented frontal boundary continues its path. Ponding of
water in roads and poorly drained areas can be anticipated, mostly
across the northeast portions of Puerto Rico and northern USVI.

Dry air behind the frontal boundary will move in promoting mostly
fair weather conditions by late Saturday night into Sunday morning.
Patches of moisture embedded in the northeasterly trades will bring
showers across windward coastal areas at times for the rest of the
short-term period.

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

A mid-level ridge over the western Caribbean will gradually move
eastward through the workweek, and build over the local area by
the end of the week. At upper levels, a trough will cause a brief
weakness of the ridge by midweek, and the trade winds will relax
and turn more from the east to east-southeast throughout the week.
Meanwhile, moisture content is expected to peak around 1.40
inches across the USVI on Monday and Tuesday, and between
0.90-1.20 inches across PR. Mostly due to the wind shift and the
lingering moisture from the old frontal boundary that is trapped
below 750 mb. Then, a drying trend is expected as the ridge builds
across the northeastern Caribbean during the latter part of the
week. Rainfall accumulations should favor the USVI and the eastern
portions of PR during the night and early morning hours each day.
However, accumulations should remain below half an inch.


&&

.AVIATION...VFR conditions are expected to prevail across
all terminals during the next 24 hours for the most part. Low-level
winds will continue from the E-NE at 10 to 15 kts, increasing to 15-
20 kts with occasional higher gusts after 24/14Z. The remnants of
frontal boundary will start to enter the CWA after 25/04z with low
to mid level clouds briefly creating SCT-BKN ceilings at FL025-FL040
with SHRA/-SHRA across local terminals, causing brief MVFR mostly to
TJSJ/TIST terminals.


&&

.MARINE...Seas will continue at 3-5 feet across the offshore
waters and passages, and at less than 3 feet across the southern
and western coastal waters of the islands. Moderate to locally
fresh northeast winds will prevail, and small craft operators
should exercise caution across the Atlantic waters, offshore
Caribbean, and the Anegada Passage. There is a moderate risk of
rip currents for most northern and east facing beaches of the
islands. A long period northerly swell(~5 ft) will increase the
risk to high on Monday.


&&

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

$$

SHORT TERM/AVIATION...CVB
LONG TERM/MARINE...DSR

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
425 AM AST Sat Feb 25 2023


.SYNOPSIS...
A showery weather pattern will prevail today due to the remnants
of an old frontal boundary. Regardless of the rain activity, we
do not anticipate flooding problems today. The risk of rip
currents along most of the exposed north and east-facing beaches
is moderate today. In addition, moderate to fresh northeasterly
winds will result in choppy marine conditions across the local
offshore water and local passages, where small craft operators are
urged to exercise caution.

&&

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

GOES-East shows the remnants of an old frontal boundary moving
across the Northeast Caribbean, increasing the Total Precipitable
Water (TPW) near 1.33 inches, as depicted with the derived TPW.
Therefore, residents of Puerto Rico and the U.S. Virgin Islands
can expect showery weather today. However, a high pressure
anchored aloft near Florida and western Cuba will create hostile
atmospheric dynamics, preventing deep convection and significant
rainfall accumulations across the region. Today's maximum
temperatures will fluctuate between the mid-80s along the coastal
areas to the upper 70s in mountains and valleys.

The ridge pattern at mid-levels will promote subsidence and dry air
aloft through the short-term period. The dry air mass behind today's
modified front, observed with GOES-East, will filter over the
islands late this afternoon into tomorrow morning, limiting rain
activity, as GFS also suggests. However, the easterlies may push a
second plume of moisture by Sunday afternoon, increasing passing
showers and cloudiness from the east.

The east-northeast winds may bring another fragment of moisture into
the region late Sunday night into Monday, increasing the likelihood
of another rainy pattern for the eastern half of Puerto Rico and the
surrounding waters of the Virgin Islands. Regardless of the rainy
conditions, we do not anticipate flooding problems.

&&

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

A variable weather pattern is expected for the long-term period.
At mid-level, a broad ridge resulting in a trade wind cap and
drier air aloft will be the limiting factor for a widespread and
long-live shower activity. At the surface, a building high
pressure over the Western Atlantic will promote moderate
northeasterly winds across the region. As in the previous days,
the northeasterly wind flow will hold the passage of frequent
pockets of moisture from the remnants of an old frontal boundary.
According to the latest model guidance, the Pwat values will range
between 1.1 to 1.5 inches each day. On Thursday, there is a
slight chance for drier conditions with a Pwat below the
climatological normals; however, it will not last long as the
arrival of another patch of moisture on Thursday Afternoon.
Giving the expected condtions on Tuesday into Thursday, expect,
variable weather pattern with pesky showers from time to time
across Puerto Rico and the U.S. Virgin Islands.

From Friday onwards, the surface high pressure will move more
eastward in response to a frontal boundary exiting the eastern
Seaboard Coast of the United States. This surface change will
result in veering winds across the region, increasing the
Caribbean water content over the forecast area. Therefore, expect
afternoon activity across the central interior, northwestern
sections of Puerto Rico, and the San Juan Metro area.
Additionally, daytime temperatures are forecast to be slightly
warmer, especially across the north- central sections of Puerto
Rico.

&&

.AVIATION...
The remnants of an old front will bring SCT-BKN ceilings between
FL020-FL060 and periods of brief SHRA/-SHRA across the terminals
through this afternoon. Most of the activity will affect
JSJ/JBQ/IST/ISX, and JPS will be impacted mainly aft 25/15z. This
activity should diminish by this afternoon (around 25/20z onward).
Winds will continue from the ENE at 10-13 knots with gusts up to 20
knots, especially near rain activity. Winds will increase at around
15-20 kt and gusts around 25 knots after 25/14z.

&&

.MARINE...

A surface high pressure will continue to promote moderate to
locally fresh northeasterly winds today across the region, with
winds up to 20 knots. As a result, some choppy marine conditions
will prevail across the offshore waters, where small craft
operators are urged to exercise caution. In general, seas will
continue at 3-5 feet across the offshore waters and passages and
at or less than 4 feet across the southern and western coastal
waters of the islands. There is a moderate risk of rip currents
for most northern and east facing beaches of the islands. A long
period northerly swell will increase the risk of rip currents to
high on Monday onwards due to a large breaking wave across the
north coast of the islands.

&&

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

$$
SHORT TERM/AVIATION...CAM
LONG TERM & MARINE....LIS

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
429 AM AST Sun Feb 26 2023


.SYNOPSIS...
A drier airmass with a few pockets of moisture will prevail for
today across the islands providing fair weather conditions with a
few passing showers, mainly over the northeastern sections of
Puerto Rico. A long period northerly swell will arrive in the
local waters for the upcoming week, turning hazardous the marine
conditions.

&&

.SHORT TERM...Tonight through Tuesday...

Today we expect mostly sunny skies under an east-northeasterly
wind flow that will push some stratified clouds across the region.
Although we expect mainly stable weather conditions without rain
activity, a few showers may form due to local effects and sea
breeze variations during the afternoon. Maximum temperatures will
range in the mid-80s (along the southern coast) and the mid-70s in
mountains or valleys.

When writing this discussion, a long-period northeasterly swell
detected around South Bermuda's buoy 41049 (630 miles and 650
miles north of St Thomas and San Juan, respectively) will create
hazardous coastal conditions across the Atlantic Coastline Monday
and Tuesday. Thus, we may observe dangerous breaking waves around
10 feet creating life-threatening rip currents from the northwest
to the northeast coast of Puerto Rico and dangerous rip currents
along the north-facing beaches of Culebra and St Thomas and St
John.

The mid-level ridge will maintain a trade wind cap between 900 mb
and 700 mb and dry air above that level. However, a moisture
fragment embedded in the trades will increase rain activity,
mainly across the U.S. Virgin Islands and eastern Puerto Rico
surrounding waters tonight into Monday.

Tuesday weather conditions may be tranquil, with a mixture of
sunshine and clouds and little or no rain due to below-normal
moisture content and stable weather conditions due to the ridge
aloft.

&&

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

A variable weather pattern will persist for the long-term period
A mid- level ridge will be the dominant feature holding a trade
wind cap inversion and drier conditions at the upper levels. At
the surface, a building high pressure over the Western Atlantic
will promote moderate northeasterly winds across the region. From
Wednesday to Thursday, cloudy skies with passing showers will
persist with the arrival of frequent patches of shallow moisture
across the region. These conditions will allow a cold advective
pattern with passing showers over the local waters, streaming over
the north coast of Puerto Rico. This activity is forecast to be
light, and no significant rainfall accumulations are expected. On
Friday into the weekend, the surface high pressure will move
eastward in response to a frontal boundary exiting the eastern
Seaboard Coast of the United States. This surface change will
result in veering winds across the region, increasing the
Caribbean water content over the forecast area. Therefore, expect
afternoon activity across the central interior, northwestern
sections of Puerto Rico, and the San Juan Metro area.
Additionally, daytime temperatures are forecast to be slightly
warmer, especially across the north- central sections of Puerto
Rico.

&&

.AVIATION...

VFR conditions will prevail today, with a few SHRA/-SHRA
developing across the interior and E-PR during the afternoon.
Winds will persist calm to light and variable through 26/13z,
returning from the ENE at around 15 kt with sea breeze variations
after 26/13z.

&&

.MARINE...
A surface high pressure will continue to promote moderate
northeasterly winds across the region, with winds up to 15 knots.
In general, seas will continue at 3-5 feet across the offshore
waters and passages and at or less than 4 feet across nearshore
Caribbean waters. There is a moderate risk of rip currents for
most northern and east-facing beaches of the islands. A long
period northerly swell will increase the seas and the risk of rip
currents to high on Monday onwards.

&&

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

$$

SHORT TERM, AVIATION...CAM
LONG TERM, MARINE....LIS

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
446 AM AST Mon Feb 27 2023

.SYNOPSIS...
Issued at 447 AM AST Mon Feb 27 2023

Today's main hazard is the arrival of a long northerly swell that
will create hazardous coastal conditions along the Atlantic
Coastline. Therefore, expect life-threatening rip currents and
dangerous breaking waves, with the possibility of observing
isolated beach erosion. In general, we expect mostly sunny skies,
but a fragment of moisture will bring some showers and clouds
across the surrounding waters of the U.S. Virgin Islands and the
eastern half of Puerto Rico. A mid-level high pressure will
promote a stable weather pattern throughout the week. However, the
winds will bring occasional patches of moisture, producing periods
of shallow rain.

&&

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

The short-term forecast remains on track. At the surface,
northeasterly winds will persist due to a surface high pressure
over the Western Atlantic. This wind flow will drag a few
stratified clouds and some patches of moisture from time to time.
Regardless of the pockets of moisture in general, for today, the
rule will be Precipitable water values reaching 0.85 inches which
are two standard deviations below the normal. In combination with
the drier conditions at the surface, the persistent mid-level
ridge will continue to provide drier air aloft and the trade wind
cap inversion between 900 MB to 700 MB.

On Tuesday, expect a relaxation in the pressure gradient and
veering winds as the surface high pressure over the western
Atlantic weakens. This change will bring a few pockets of tropical
moisture, causing a few passing showers across the Caribbean
waters. This wind pattern will not last long, as another surface
high pressure builds over the western around Wednesday, inducing
northeasterly winds.

Overall, expect mostly clear skies throughout the forecast period,
with occasional passing showers.

&&

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

The mid-level high pressure will slowly drift eastward across the
Northeast Caribbean, promoting stable weather conditions and dry
air aloft through at least early next week. The available moisture
will be trapped below 700 MB, as GFS and ECMWF suggest. Thus,
expect a mixture of sunshine and clouds, with pleasant
temperatures, but with the arrival of occasional showers mainly
across the windward sections of Puerto Rico and the U.S. Virgin
Islands each day.

A surface high pressure is forecast to enter the Western Atlantic
early Thursday morning and will move eastward into the Central
Atlantic, tightening the local pressure gradient by this weekend.
As a result, windy east-to-east-southeast winds may affect the
region during the weekend.

A cold front will exit the Eastern Seaboard by the weekend and may
approach the islands early next week, and may promote cloudy and
showery weather. However, confidence in this solution is still
low-moderate because it is at the end of the forecast period.

&&

.AVIATION...
(06Z TAFS)
Issued at 447 AM AST Mon Feb 27 2023

VFR conditions will prevail during the forecast period for all TAF
sites. Winds will continue from the E-NE below 6 kts, increasing
to 10 kts by 27/14Z. Winds will become VRB around 28/00Z onward.
VCSHs are possible across TISX in the evening.

&&

.MARINE...
Issued at 447 AM AST Mon Feb 27 2023

Mariners can expect increasing seas between 4 and 6 feet across
the Atlantic Waters and Caribbean Passages due to the arrival of a
long period northerly swell (wave period between 14 and 16
seconds). Small craft operators should exercise caution across the
Atlantic Offshore and Coastal Waters. The winds will be from the
east to northeast at 5 to 15 knots.

The long-period nature of the northerly swell will create sudden
breaking waves that could surpass ten feet in the morning and
afternoon, lasting through at least tomorrow morning. Therefore, a
High Surf Advisory with a High Risk of life-threatening rip
currents is in effect for the Atlantic Coastline of Puerto Rico
(from northwest to northeast). The risk of rip currents is also
high for Culebra, St Thomas, and St John, while it will be
moderate for the north coast of Vieques and the eastern half of St
Croix. Please refer to the Coastal Hazard Message (CFWSJU) for
more details.

&&

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

High Surf Advisory until 6 AM AST Tuesday for PRZ001-005-008.

High Surf Advisory from 6 PM this evening to 6 AM AST Tuesday
for PRZ002.

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

AM...None.
&&

$$

SHORT TERM/AVIATION...LIS
SYNOPSIS/LONG TERM/MARINE....CAM

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
511 AM AST Tue Feb 28 2023

.SYNOPSIS...
Issued at 510 AM AST Tue Feb 28 2023

Expect mostly clear skies with little or no rain today. The
coastal conditions continue to be hazardous due to dangerous
breaking waves across the Atlantic Coastline of Puerto Rico and
strong rip currents along Aguada, Rincon, Culebra, St Thomas/St
John, and later this afternoon across St Croix. A mid-level high
pressure will promote a stable weather pattern throughout the
week, with the arrival of occasional patches of moisture embedded
in the winds. A showery weather pattern may be possible for early
next week.

&&

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

GOES-16 Satellite-derived imagery shows a slot of drier airmass
moving across the region with PWAT values around 0.75 to 0.8
inches. The dry air mass at the surface and the subsidence caused
by the mid-level ridge will promote mostly sunny skies this
morning with a few thin clouds.

Winds will become slightly more from the east-southeast in
response to the interaction between the surface high pressure
across the western Atlantic and low pressure moving eastward out
of the Eastern Seaboard of the U.S. This wind change will be
drifting the possible afternoon showers more to the west and
northwestern Puerto Rico. Backing wind will be in place as the
surface high pressure rebuilds on Wednesday. Embedded in the
northeasterly, patches of moisture will reach the local islands
causing an advective pattern Wednesday and Thursday. Rainfall
accumulations will not be significant; therefore, we do not expect
any flooding threat during the period.

&&

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

Model guidance continues indicating the presence of a mid-level
high pressure over the Northeast Caribbean, promoting stable
weather conditions and dry air aloft through at least early next
week. The only discrepancy with the previous model runs is the
arrival of the patches of moisture, but the available moisture
will be trapped below 700 MB, as GFS and ECMWF suggest. Thus,
expect a mixture of sunshine and clouds, pleasant temperatures,
and the arrival of occasional showers, mainly across the windward
sections of Puerto Rico and the U.S. Virgin Islands each day.
Afternoon convection may develop across the interior and western
PR and downwind from the USVI daily without flooding threats.

Local winds may increase during the weekend as a surface high
pressure is forecast to move eastward from the Western Atlantic
into the Central Atlantic, tightening the local pressure gradient.

Model guidance again has a cold front exiting the Eastern
Seaboard around Saturday and approaching the islands early next
week. This feature could promote cloudy and showery weather around
late Monday night or Tuesday. Discrepancies in the timing and
moisture pooling may occur during the next few days; therefore,
the confidence continues to be low/moderate.

&&

.AVIATION...
(06Z TAFS)
Issued at 510 AM AST Tue Feb 28 2023

VFR conditions will prevail across all the TAF sites. Wind will
continue calm to light/variable through 28/14Z, becoming more from
the E-NE at 10 knots with sea breeze variations afterward. Cloud
cover will increase over/near TISX around 28/22Z. Winds will
become lighter between 28/22Z/01/03Z.

&&

.MARINE...
Issued at 510 AM AST Tue Feb 28 2023

Mariners can expect seas between 4 and 6 feet across the Atlantic
Waters and Caribbean Passages due to a fading long-period
northerly swell. Small craft operators should exercise caution
across these waters. The winds will be from the east to east-
southeast at 5 to 15 knots, returning from the east-northeast to
the northeast on Wednesday.

Although conditions will somewhat improve today, hazardous coastal
conditions will continue due to the long-period nature of the
northerly swell. Therefore, expect breaking waves around 10 feet
from the northwest to northeast exposed beaches of northern Puerto
Rico. Aguada, Rincon, Culebra, and St Thomas/St John will also
have a high risk of strong rip currents due to breaking waves
between 6 and 9 feet. The chance of observing strong rip currents
will become high in the eastern tip of St Croix later this
afternoon. Therefore, a High Surf Advisory with a High Risk of
life-threatening rip currents is in effect for the Atlantic
Coastline of Puerto Rico (from northwest to northeast). The risk
of rip currents is also high for Culebra, St Thomas, and St John,
while it will be high for St Croix later this afternoon. Please
refer to the Coastal Hazard Message (CFWSJU) for more details.

&&

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

High Surf Advisory until 2 PM AST this afternoon for PRZ001-002-
005-008.

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

High Rip Current Risk from 2 PM AST this afternoon through late
tonight for VIZ002.

AM...None.
&&

$$

SHORT TERM/AVIATION...LIS
SYNOPSIS/LONG TERM/MARINE....CAM

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
445 AM AST Wed Mar 1 2023

.SYNOPSIS...
Issued at 445 AM AST Wed Mar 1 2023

Expect sunny skies, pleasant temperatures, and little to no rain
today. Hazardous coastal conditions due to dangerous breaking
waves continue across the Atlantic Coastline of Puerto Rico and
strong rip currents along Aguada, Rincon, Culebra, St Thomas/St
John, and St Croix. A mid-level high pressure will promote a
stable weather pattern throughout the week, with the arrival of
occasional patches of moisture embedded in the winds. A short wave
trough aloft and a modified frontal boundary across the surface
will approach the region early next week.

&&

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

Satellite-derived imagery shows below-normal dry air mass with
PWAT values of 0.67 inches, two standard deviations below the
March climatological normal. The lack of moisture and the trade
wind cap resulting from the mid-level ridge holding through the
period will aid mostly clear skies throughout the day. In the
afternoon, local effects could induce cloudiness across the
mountains, but the rain chances are low due to the lack of
moisture in the area.

A slight change in the wind pattern will induce veering winds on
Thursday into Friday as the surface high pressure elongates over
the Atlantic in response to a low pressure moving well north of
the Atlantic. This wind pattern will bring fragments of surface
moisture from the old frontal boundary across the CWA. This
increase in low-level moisture will enhance some showers across
the local waters and the development of some afternoon convection
over the west and northwest Puerto Rico. A tightening of the
pressure gradient will induce breezy conditions late Friday.

Generally, the people in PR/USVI can expect periods of clear
skies for Thursday into Friday, with some passing showers across
the eastern sections of the Islands. Regardless of the increase in
the probability to rain, the flood threat is null for the area.
Slightly warmer daytime temperatures could be present due to the
east-southeast winds on Friday.

&&

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

The mid-level high pressure will continue over the Northeast
Caribbean through at least Monday, promoting stable weather
conditions and dry air above around 700 MB. Model runs have some
discrepancies with the arrival and the magnitude of the patches of
moisture. Thus, expect a mixture of clear skies and clouds,
pleasant temperatures, and the advent of occasional showers,
mainly across the windward sections of Puerto Rico and the U.S.
Virgin Islands each day. Sea breeze variations and local effects
may result in afternoon convection across the interior and western
PR and downwind from the USVI daily, but without flooding
threats.

The forecast indicates the possibility of increasing winds on
Saturday as a surface high pressure tightens the local pressure
gradient when it builds northeast of the region.

A cold front will leave the Eastern Seaboard around Saturday and
will approach the islands early next week. It may increase the
available surface moisture from Monday evening through Wednesday.
In addition, an upper to mid-level shortwave trough will swing by
the region and may weaken the mid-level ridge, promoting more
instability. These atmospheric features could promote cloudy and
showery weather on those days. However, the latest runs indicate
less available moisture, which could be a limiting factor for the
development of widespread rain activity. Due to the discrepancies
in the timing and moisture pooling we have observed between the
past model runs, the confidence remains low/moderate for a showery
weather pattern.

&&

.AVIATION...
(06Z TAFS)
Issued at 445 AM AST Wed Mar 1 2023

VFR conditions will persist for all the TAF sites. Winds will
remain VRB at 5 knots or less, increasing between 8 to 10 knots
aft 01/14Z. SKC will persist through around 01/15Z, then sea
breeze variations and local effects will induce cloudiness over
the islands' mountains. Winds will diminish again aft 02/00Z. No
significant impacts are expected.

&&

.MARINE...
Issued at 445 AM AST Wed Mar 1 2023

A long period northeast swell will move across the Atlantic
Waters and Caribbean Passages, maintaining seas between 4 and 6
feet. Therefore, small craft operators should exercise caution
across these waters. The winds will be from the east-northeast at
5 to 15 knots, increasing around Friday and Saturday.

Hazardous coastal conditions across the Atlantic Coastline in
PR/USVI will continue due to the long-period nature of the
northeasterly swell. Therefore, expect breaking waves around 10
feet from the northwest to northeast exposed beaches of northern
Puerto Rico. Aguada, Rincon, Culebra, St Thomas/St John, and St
Croix will also have a high risk of strong rip currents due to
breaking waves between 6 and 9 feet. Therefore, a High Surf
Advisory with a High Risk of life-threatening rip currents is in
effect for the Atlantic Coastline of Puerto Rico (from northwest
to northeast). The risk of rip currents is also high for Culebra,
St Thomas, St John, and St Croix. Please refer to the Coastal
Hazard Message (CFWSJU) for more details.

&&

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

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

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

AM...None.
&&

$$

SHORT TERM/AVIATION...LIS
SYNOPSIS/LONG TERM/MARINE....CAM

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
450 AM AST Thu Mar 2 2023

.SYNOPSIS...
Expect generally dry and stable weather conditions and typical
seasonal temperatures to prevail across the islands. A long period
northeasterly swell continues to cause breaking waves up to 10
feet today, with another pulse arriving tonight to continue this
trend. Trade winds will strengthen by tomorrow as an area of high
pressure builds north of the region. The winds will veer over the
weekend, becoming southeasterly which will increase the amount of
shower activity as moist air moves into the region.

&&

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

No significant changes within the expected weather pattern during
the next few days, with generally dry and stable environmental
conditions maintaining fair weather favorable for outdoor
activities. Despite these conditions, marine conditions at limited
to elevated and life-threatening rip currents at high hazard risk
levels will persist through the period. Limited wind hazard risk
level is likely by Friday into the weekend.

A deep-layer high pressure system will remain the dominant feature
across the region, promoting variations in the general wind flow as
it streams eastward across the western Atlantic. East-northeasterly
winds at 10-15 mph, increasing to 10-20 mph and veering east-
southeasterly by Friday and back to the east on Saturday. At mid-
levels, the same high will maintain hostile conditions for deep
convective development with a strong trade wind cap inversion and
drier air entrainment aloft. Although shallow patches of moisture
associated with the remnants of an old frontal boundary will reach
the area on Friday, causing a slight increase in moisture and
passing shower activity, below-normal seasonal moisture levels, and
limited shower activity will persist.

Typical seasonal temperatures will prevail, ranging from the mid 80s
across coastal and other urban areas during the day to around 50
degrees across higher elevations at nighttime. Slightly warmer
temperatures are possible on Friday under east-southeasterly winds.
Slight lower temperatures are likely with clearer nights. Fog
development is expected across the interior between the late night
and early morning hours, creating hazardous driving conditions.

&&

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

High pressure at the surface in the central Atlantic will promote
a south-southeasterly wind flow on Sunday into early next week.
Moist air should reach the region as a result of this, causing an
increase of rainfall during this time. However, a ridge in the mid
to upper levels will maintain stable conditions. Slightly higher
temperatures are to be expected across northern sections of Puerto
Rico. On Monday, a polar trough stretched down through the North
Atlantic will reduce stability across the mid and upper levels,
along with patches of moisture moving in, so an increase of clouds
and showers is forecast. Most rainfall should be seen across the
eastern half of the region, eastern PR and the USVI, with some
light afternoon rain across the interior to northwestern areas of
PR.

Tuesday and Wednesday look quite dry as precipitable water values
are projected to be below normals. Later in the week beginning
Thursday, the lower level wind flow starts to back, becoming light
with a variable direction mainly from the north as a large frontal
cyclone in the northern Atlantic stretches southward. The frontal
boundary will begin approaching the region by Friday. This should
bring an advective pattern of showers to reach the northern
coastlines along with slightly cooler temperatures for the islands.

&&

.AVIATION...VFR conditions will prevail across all terminals
during the next 24 hours. Calm to light and variable winds
increasing after 02/12Z to 10-15 mph around 02/18Z with higher gusts
and sea breeze variations. Winds will once again become light and
variable after 02/22Z. Impacts from occasional trade wind SHRA will
be brief, mainly across USVI terminals.

&&

.MARINE...A long period northeasterly swell continues to affect
the Atlantic waters and passages, however the main concern is
breaking waves up to 10 feet across northern facing coastlines.
Sea heights are generally around 5 feet, with occasionally greater
waves. There is another pulse of swell that will arrive tonight
and trade winds will strengthen over tomorrow, together causing
choppy seas into the early part of the weekend.

This being said, there is a High Surf Advisory for the Northern
Coastline of Puerto Rico that is ending this morning yet another
one may be issued for tomorrow with the next package due to the
continuing hazardous trend. However, the High Rip Current Risk
statement will be in effect through at least tomorrow as surf
heights remain 6 feet or greater.


&&

.FIRE WEATHER...The lack of significant wetting rainfall continues to support
further drying of soils across the southern Coastal plains of
Puerto Rico, were KBDI value have exceeded fire danger thresholds.
With more dry air entering the region, no wetting rainfall is
expected over today. RH values are expected to drop into critical
values and with the strengthening of winds around noon, fire
weather criteria may be met. Due to all of this, an RFD has been
issued for the Southern Coastal Plains of Puerto Rico.


&&


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

High Surf Advisory until 8 AM AST this morning for PRZ001-002-
005-008.

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

AM...None.

&&

$$

SHORT TERM...ICP
LONG TERM....RC

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
500 AM AST Fri Mar 3 2023

.SYNOPSIS...
Confused, choppy seas will prevail today and tomorrow due to the
mix of a northeasterly swell and moderate to locally strong
easterly winds. Windy conditions will prevail today and tomorrow
over land with a few passing showers and afternoon showers,
providing small amounts of rain. However, on Sunday an increase
of rainfall is forecast as wetter weather conditions are likely.
During the next few days, temperatures should be slightly warmer
due to a southeasterly component in the general wind flow and
likely increase in cloud coverage. Next week calm weather
conditions are to be expected as winds weaken and dry air
dominants.

&&

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

Marine conditions at limited to elevated, rip currents at moderate
to high, and wind at limited hazard risk levels will persist through
the period.

A deep-layer high pressure will remain the dominant feature across
the region. East-southeasterly winds at 10-20 mph, becoming more
easterly on Saturday and decrease to 10-15 mph on Sunday will
dominate the region. At mid-levels, the same high will maintain
hostile conditions for deep convective development with a strong
trade wind cap inversion and drier air entrainment aloft, confining
moisture below the 850 mbar layer.

Despite moisture confined to the lower levels, slightly wetter
weather conditions are likely as the remnants of an old frontal
boundary cause precipitable water values to reach and remain near-
normal seasonal levels during most of the period, peaking at around
1.3 inches this evening and 1.5 inches by Sunday afternoon. That
said, expect an increase in shower activity during these periods,
reflected in increased afternoon convective development over western
sections of the islands and passing shower activity mainly at
nighttime, affecting windward areas. Still, pockets of drier air
will reach the region at times, with the driest periods and
generally fair weather conditions expected by Saturday morning and
late Sunday night.

Diurnal temperature variations should be slightly warmer than
previous days due to a southeasterly component in the general wind
flow and likely increase in cloud cover, ranging from the mid to
upper 80s across coastal and other urban areas during the day to mid
to upper 50s across higher elevations at nighttime. Yet, slightly
lower minimum temperatures are likely in areas with clearer skies.
Typical seasonal temperatures will return on Saturday and Sunday.
Fog development is possible across the interior between the late
night and early morning hours, creating hazardous driving
conditions.

&&

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

A pattern of passing showers across windward areas followed by light
afternoon convection is to be expected on Monday as easterly flow
moves a patch of moist air in. A ridge in the mid levels across the
Caribbean Basin maintains stable conditions, preventing any
impressive rainfall. A drying trend will begin Monday night as an
area of high pressure builds northwest of the region, promoting a
dry, northeasterly lower level flow. Dry, fair weather conditions
with clear skies to partly cloud skies is to be expected from
Tuesday to Friday morning due to the lack of lower level moisture.
Starting Wednesday, Wind flow becomes light and variable,
generally from the north. An upper level westerly jet may produce
cirrus clouds across the skies during this time. On Friday into
the weekend, the impacts of a frontal boundary to the north of
the region are still uncertain as a moist southerly flow
strengthens south of the region, arriving from eastern Caribbean.
Most likely scenario is an increase of passing showers across
northern Puerto Rico and the USVI.

Overall, a mild weather pattern of clear to variably cloud skies is
be expected after some passing shower activity on Monday.
Temperatures during this time will be slightly warmer than usual
during the day time and slightly cooler during the night as clear
skies lets the sun heat up the land and then allows the heat to
escape at night. This is all followed by a possible wet weekend
as southerly flow may move a moist air mass over the region.

&&

.AVIATION...Mainly VFR conditions will prevail across all
terminals during the next 24 hours. Afternoon SHRA with SCT-BKN at
FL020-030 could result in brief MVFR conditions across all PR
terminals between 03/16-22Z. Calm to light and variable winds
increasing after 03/12Z to 10-20 mph around 03/18Z with higher
gusts and sea breeze variations. Winds will once again become
light and variable after 03/23Z.

&&

.MARINE...A long period northeasterly swell will combine with
locally generated wind waves to produce confused, choppy seas
today through Saturday. Moderate to locally fresh easterly winds
will veer throughout the day, becoming south-southeasterly by this
evening. Conditions will slowly improve on Sunday, becoming much
more favorable by next week.

There is currently a High Surf Advisory for the northern coastline
of Puerto Rico, including Culebra, and for northern/eastern facing
beaches of St. Croix due to breaking waves around 10 feet. Most
other northern/eastern facing beaches have a High Rip Current Risk
today into the weekend. Tonight, a Small Craft Advisory will be in
effect for the Atlantic Offshore Waters and then tomorrow for the
Northern Coastal Waters of PR and USVI, Mona Passage, and the
Anegada passage. Small Craft should exercise caution elsewhere.

&&

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

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

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

High Surf Advisory until 6 PM AST Saturday for VIZ002.

AM...Small Craft Advisory from 8 PM this evening to 2 AM AST Sunday
for AMZ710.

Small Craft Advisory from 8 AM to 8 PM AST Saturday for AMZ712-
715-722-741.

&&

$$

SHORT TERM...ICP
LONG TERM....RC

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
457 AM AST Sat Mar 4 2023

.SYNOPSIS...
An area of high pressure to the north will promote easterly to
east- southeasterly winds between 10 and 20 mph through the
weekend. Generally fair weather conditions will prevail for the
next few days yet shower activity is possible as intermittent
patches of shallow moisture stream across the area. By Wednesday
the surface wind flow will calm, then become northerly until next
weekend. A frontal boundary is forecast to pass over the region
early Friday morning, increasing showers across northern Puerto
Rico and the USVI.

A long period northeasterly swell remains present across
our Atlantic waters and wind speeds over the waters are expected
to strengthen today. As a result, hazardous marine and coastal
conditions will continue with multiple High Surf Advisories, Small
Craft Advisories, and High Rip Current Risk Statements in effect.
See the Marine section below for more details.

&&

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

Marine conditions at limited to elevated and wind at a limited
hazard risk levels will persist through Saturday. In contrast, rip
currents hazard risks will remain moderate to high throughout the
cycle.

The dominant feature, a deep-layer high pressure, will remain over
the region through Sunday before gradually dissipating by Monday as
a frontal boundary sinks southward across the western Atlantic. The
high will promote easterly to east-southeasterly winds at 10-20 mph
today and on Sunday, but the proximity of the frontal boundary will
lead to more east-northeasterly winds at lower speeds by Monday. At
mid-levels, the hostile conditions for deep convective development
with a strong trade wind cap inversion and drier air entrainment
aloft will prevail. However, conditions may favor deeper convection
over the islands as the trade wind cap inversion gradually weakens
by early next week. Despite these conditions, below-normal seasonal
moisture levels and generally fair weather conditions will prevail
through the cycle, with precipitable water (PWAT) values as low as
0.70 inches by Sunday night. Still, shower activity is possible as
intermittent patches of shallow moisture stream across the area,
with PWAT as high as 1.2 inches. Based on the most recent satellite
imagery in agreement model guidance, these patches should reach the
local islands this evening, Sunday afternoon, and Monday afternoon,
enhancing passing shower activity and afternoon convective
development. Rainfall accumulations should remain minimal, but
locally higher amounts of up to three-quarters of an inch are
possible. Contrary, periods with breezy and drier conditions, along
with further drying of soils and fuels, may favor elevated fire
danger hazard risks, mainly across fire-prone areas of southern
Puerto Rico between the late morning and early afternoon hours.

Typical seasonal temperature variations will prevail, ranging from
the mid 80s across coastal and other urban areas during the day to
around 50 degrees across higher elevations at nighttime. Yet,
slightly lower minimum temperatures are likely in areas with clearer
skies. Fog development is possible across the interior between the
late night and early morning hours, creating hazardous driving
conditions.

&&

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

On Tuesday, An area of high pressure to the northwest, east of
Florida, will maintain a variable easterly flow that should provide
typical weather consisting of a few passing showers across eastern
PR and the USVI, with afternoon activity across western Puerto
Rico. However, there will be a noticeable change in the weather
as a broad frontal cyclone begins to develop across the North
Atlantic Basin late on Tuesday, existing to the east of a high
pressure system situated over Canada. This wave pattern will cause
a convergence of northerly winds, eliminating any surface high
pressure in the western northern Atlantic. This will replace the
typical trade wind regime with variable light to moderate
northerly winds. The surface flow transition should occur on
Wednesday, starting with a defined land breeze during the morning
hours, followed by calm winds throughout the day. By early
Thursday, this pattern of cool northerly winds will bring frequent
passing showers across the northern coast of the islands, however
moisture content is shallow and limited so no heavy rainfall is
anticipated.

The frontal boundary associated with the aforementioned frontal
cyclone will arrive to the region Thursday night, significantly
increasing the rate of showers across northern sections of Puerto
Rico and the USVI. Ponding of water across urban areas is possible
during this time due to the frequency of showers. Moist, northerly
flow continues throughout Friday into Saturday so a continued
pattern of passing showers is to be expected. During this event,
temperatures will be cooler than usual due to cold air advection
from the north.

&&

.AVIATION...Mainly VFR conditions will prevail across all
terminals during the next 24 hours. Afternoon SHRA with SCT-BKN at
FL020-030 could result in brief MVFR conditions across TJSJ and TJBQ
terminals between 04/17-22Z. Calm to light and variable winds
increasing after 04/12Z to 10-20 mph around 04/18Z with higher gusts
and sea breeze variations. Winds will once again become light and
variable after 04/23Z.

&&

.MARINE...A long period northeasterly swell remains present across
our local waters as another reinforcing pulse arrives this
morning. Also, an area of high pressure north of the region has
strengthen the local winds and as a result wind speeds between 15
to 20 knots with higher gust from the east-southeast are to be
expected today. The combination of the ground swell and wind waves
are raising seas to heights between 5 and 8 feet with
occasionally greater heights up to 10 feet. A Small Craft
Advisory is in effect today for the Atlantic Waters and passages
and the eastern Caribbean Waters near St. Croix. See the Marine
Weather Message (MWWSJU) for more details.

Breaking waves are reaching up to 11 feet for the northern exposed
beaches of Puerto Rico from Aguadilla to the beaches of Culebra
and for St. Croix, therefore there is a High Surf Advisory out
until 6 AM tomorrow. Rincon, the northern USVI, and Vieques are
seeing breaking waves up to 9 feet, therefore there is a High Risk
for Rip Currents until at least tomorrow afternoon, and this risk
applies to the areas with a High Surf Advisory as well. For more
information check out the Coastal Hazard Message (CFWSJU) and the
Surf Zone Forecast (SRFSJU).


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

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

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

High Surf Advisory until 6 AM AST Sunday for VIZ002.

AM...Small Craft Advisory until 2 AM AST Sunday for AMZ710-712-715-
741.

Small Craft Advisory until 8 PM AST this evening for AMZ722.

Small Craft Advisory from 8 AM this morning to 8 PM AST this
evening for AMZ732.

&&

$$

SHORT TERM...ICP
LONG TERM....RC

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
437 AM AST Sun Mar 5 2023


.SYNOPSIS...
A lingering northeasterly swell is maintaining breaking waves
around 7 feet for northern and eastern exposed beaches. Afternoon
showers are forecast for today however no significant rainfall is
expected. Moist air will move into the region on Tuesday,
increasing the amount showers seen throughout the day. Mid-week
looks dry until a frontal boundary passes by Thursday evening,
beginning a wetter pattern of passing showers across northern PR
and the USVI.

&&

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

Marine conditions and wind at limited hazard risk levels will
continue today. Limited impacts from excessive rain are likely on
Monday. In contrast, rip currents hazard risks will remain moderate
to high throughout the period.

A deep-layer high pressure will begin to dissipate today as a
frontal boundary and associated pre-frontal trough sink southward
across the western Atlantic and settles north of the local islands.
This transition will influence the general wind flow; east-
southeasterly winds at 10-20 mph today will become more east-
northeasterly at 10-15 mph on Monday, then weakening even further
and becoming variable on Tuesday. The prevailing hostile conditions
induced by the mid-level ridge will gradually become favorable for
deep convective development with the erosion of the trade wind cap.
Nonetheless, moisture will remain confined to the lower levels but
slightly higher than in previous days within the 700 mbar layers.

Despite these conditions, intermittent patches of moisture and
relatively drier air will continue to dominate the local weather
condition. For today, and based on the most recent model guidance in
agreement with satellite imagery, a patch of moisture will reach the
islands around 15-21Z (1100-1700 local time), the ideal time to
support streamer-like shower development downwind from the local
islands and El Yunque into eastern Puerto Rico and the metropolitan
area, followed by afternoon convective development across the
western interior to western sections of Puerto Rico. Since
conditions aloft for deep convective development will remain
hostile, rainfall totals should remain below a quarter of an inch. A
patch of drier air will quickly follow, leading to dry and stable
weather conditions during the overnight and early morning hours.
Weather conditions will then become slightly wetter on Tuesday as a
patch with higher moisture content, as high as 1.4 inches, moves in,
causing an increase in shower activity from both advective and
convective origin. The expected moderate to locally heavy rains
could lead to flooding impacts, mainly from ponding of water on
roadways and poorly drained areas.

Typical seasonal temperature variations will prevail, ranging from
the mid 80s across coastal and other urban areas during the day to
around 50 degrees across higher elevations at nighttime. Yet,
slightly higher (lower) maximum (minimum) temperatures are possible
in urban areas (areas under clearer skies). Fog development is
possible across the interior between the late night and early
morning hours, creating hazardous driving conditions.


&&

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

The development of a broad frontal cyclone across the North
Atlantic Basin and a high pressure system situated over North
America will cause a convergence of northerly winds, replacing the
typical trade wind regime with variable light to moderate
northerly winds starting Wednesday until Sunday when easterly
flow returns. Wednesday and early Thursday look to be rather dry
with low moisture values for most of the region. However, a
frontal boundary will approach the region by Thursday afternoon,
producing a significant increase of showers across northern Puerto
Rico and the USVI. By Friday moisture will have dropped yet
passing showers are still likely as winds around 10 knots from the
north will prevail. Better moisture flows in by Saturday maintaining
the same weather pattern of passing showers across the northern
portions of the islands. Winds start to return to an easterly
flow on Sunday, returning a typical weather regime. During this
time, across the upper levels a westerly jet will dig over the
region, potentially aiding in divergence aloft, enhancing shower
activity, and also advecting in some upper level clouds producing cloudy
skies.

Noticeable changes in the weather include calmer winds from the
north, cooler minimum and maximum temperatures across both coastal
and mountainous regions, and better rainfall for northern Puerto
Rico and the USVI Thursday throughout the weekend. No major flooding
threat is expected, however there should be an impressive amount
of rain across previously dry areas as the frontal boundary moves
into the region on Thursday.


&&

.AVIATION...VFR conditions will prevail across all terminals
during the next 24 hours. Calm to light and variable winds
gradually increasing after 05/13Z to 10-20 mph around 05/18Z with
higher gusts and sea breeze variations. Winds will once again
become light and variable after 05/23Z. Impacts from occasional
trade wind SHRA will be brief, mainly at TJSJ and USVI terminals.

&&

.MARINE... A northeasterly swell continues to linger across the
local Atlantic waters and passages, weakening over the next few
days. Moderate to locally fresh easterly winds are maintaining
moderate choppy seas todays, however winds are in a weakening
trend as we enter the week. Wind flow will become northerly by
Wednesday. Another strong northerly swell is forecast to begin
arriving on Thursday, causing hazardous marine and coastal
conditions.

For Today, a High Surf Advisory ends for the northern coastline
of Puerto Rico and St. Croix, however a High Rip Current Risk
continues to exist for most northern and eastern facing beaches as
breaking waves heights are reaching up to around 7 feet. Due to
choppy seas, small craft should exercise caution.


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

High Surf Advisory until 6 AM AST early this morning 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 VIZ002.

High Surf Advisory until 6 AM AST early this morning for VIZ002.

High Rip Current Risk through this afternoon for VIZ001.

AM...None.

&&

$$

SHORT TERM...ICP
LONG TERM....RC

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
435 AM AST Mon Mar 6 2023


.SYNOPSIS...Mainly fair weather conditions are expected today
across much of the area today. Passing showers will be observed
from time to time across the eastern and northern portions of
Puerto Rico, and the USVI during the morning hours. Then in the
afternoon hours, shower development is possible across the western
interior to western sections of Puerto Rico. Marine conditions
will continue to improve today. However, another northerly swell
is expected to reach the local waters by the end of the work-week.


&&

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

Moderate to locally heavy rains will support limited excessive rain
hazard risk today. By Wednesday, the moderate rip current hazard
risk will elevate to high.

A dissipating surface high pressure will continue to promote a
generally light to moderate easterly wind flow until late tonight
when a frontal boundary and the associated pre-frontal trough
sinking southward across the western Atlantic closes enough to
promote lighter and more variable winds. Although a mid-level ridge
will be steered southward into the Caribbean region by a polar
trough moving across the western Atlantic, conditions will remain
hostile conditions for deep convective development. By Tuesday,
conditions will slowly become favorable with the weakening of the
trade wind cap inversion, allowing moisture climbing into the 700
mbar layers.

Despite these conditions, intermittent patches of moisture and
relatively drier air will drive the local weather condition, but at
a slow frequency, given the light intensity of the steering flow.
For today and tonight, based on the most recent model guidance in
agreement with satellite imagery, a patch of shallow moisture, with
precipitable water as high as 1.4 inches, will stream across the
area, supporting passing shower activity moving inland over northern
and eastern sections, followed by afternoon convection development
across the western interior to western sections of Puerto Rico.
Streamer-like showers downwind from the local islands and El Yunque
are possible in the afternoon. Given the conditions aloft, rainfall
totals should remain below a quarter of an inch, but isolated higher
amounts are possible with the afternoon activity across the
southwestern hills, where impacts from ponding of water on roadways
and poorly drained areas is likely. From Tuesday onwards, a patch of
drier air will gradually lead to drier and stable weather
conditions, with precipitable water values falling as low as 0.70
inches by Wednesday afternoon. Afternoon convective development is
still likely each afternoon.

Typical seasonal temperature variations will prevail, ranging from
around 85 degrees across lower elevations during the day to
approximately 50 degrees across higher elevations at nighttime. Yet,
slightly higher (lower) maximum (minimum) temperatures are possible
in urban areas (areas under clearer skies). Fog development is
possible across the interior between the late night and early
morning hours, creating hazardous driving conditions.

&&

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

A frontal boundary is forecasted to reach the region by late
Thursday into Friday, increasing moisture and producing showers
across portions of northern Puerto Rico, and the US Virgin Islands.
Although, this front is expected to move quick across the local
area, some significant precipitation could be observed across the
islands. Therefore, the main hazard for this event will be minor
flooding and ponding of water in roads and poor drainage areas. The
general wind flow is expected from the north at 10 kts. The
Precipitable Water content between 1.35 and 1.55 suggest moisture
content will be present and showery weather will be expected. By mid-
morning on Friday, this front is forecasted to be located south of
Puerto Rico and the US Virgin Islands. Expect passing showers from
time to time due to fragments of moisture behind the front. From
Saturday onwards, a drier air mass will establish across the local
area, and seasonal weather will return. Shower activity will be
limited and seasonal temperatures across the islands is forecasted.
Expect pleasant temperatures, and nice weather. By the beginning
of the workweek, winds will return from the east. During the
afternoon hours with the available moisture, diurnal heating and
local effects some convection is possible across the central
interior and western portions of Puerto Rico. This pattern is
expected to prevail until mid-week. 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 will prevail across all
terminals. Brief MVFR conditions are possible with SHRA and SCT-BKN
at FL020-030 across TJSU and TIST after 06/14Z and TJPS after
06/22Z. Calm to light and variable winds gradually increasing after
06/13Z to 10-15 mph around 06/18Z with higher gusts and sea breeze
variations. Winds will once again become light and variable after
06/22Z. Impacts from occasional trade wind SHRA will be brief,
mainly at TJSJ and USVI terminals.


&&

.MARINE...Light to moderate easterly winds will prevail today and
then becoming more northeasterly and weakening by Tuesday night.
Mariners can expect seas between 3 to 5 feet across the Atlantic
waters, and 2 to 4 in the Caribbean waters and passages. Another
northerly swell will promote hazardous marine conditions for small
craft by the end of the workweek. Although, the rip current risk
is moderate in the northern beaches of Puerto Rico and the USVI,
life-threatening rip currents are possible across the exposed
waters.

&&

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

$$

SHORT TERM/AVIATION...ICP
LONG TERM/MARINE....GRS

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
450 AM AST Tue Mar 7 2023

.SYNOPSIS...Mainly fair weather conditions are forecasted today
across the local islands. However, during the afternoon hours
some showers are expected to develop across the Cordillera
Central. A northerly swell is expected to arrive to our local
waters by Thursday, deteriorating the marine conditions once again
across the waters.

&&

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

Weak steering winds due to a col area developing over the
northeastern Caribbean will prevail through at least Wednesday. The
ill-defined flow today will cause showers to develop mainly over the
Cordillera Central and may linger through the evening hours over
coastal areas. Up to half an inch of rain can be expected with this
activity. On Wednesday, steering winds acquire a northwesterly
component, and a shift in afternoon convection is expected over
southeastern PR. PWAT values are forecast to remain under seasonal
values at less than 1 inch. Across the USVI, little to no rainfall
is expected through Wednesday. PWAT is expected to increase to
around 1.50 inches by 15z on Thursday, as a cold front sink
southwards over the Atlantic waters. Therefore, cloudiness and
showers will increase across the islands by midday onwards. Ponding
of water in roads and in poor drainage areas can be expected with
these showers.

&&

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

A frontal boundary is forecasted to cross the local area by early
Friday. This front is expected to enhance moisture across the area,
and developing showers along the northern coast of Puerto Rico.
Although, the US Virgin Islands and the rest of Puerto Rico will
also observe an increase in moisture and rains through mid-morning
on Friday. The Precipitable Water content is expected to range
between 1.40 and 1.60 inches. The general wind flow front the
north will help to maintain cooler temperatures across the Central
Cordillera overnight. By late Friday into Saturday, as the front
continues to move well south of the area, a mass of drier air will
establish across the region, limiting shower development across
the islands. However, passing showers could be seen every morning
across the eastern portions of Puerto Rico and the USVI. By the
beginning of the workweek, tropical moisture will lift from the
Caribbean and South America and move towards the local area. An
enhancement in moisture will result in developing shower activity
across the islands. Remnants of a second frontal boundary are
expected to reach the area by Tuesday and the combination of this
front and the tropical moisture may result in 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.

&&

.AVIATION...Mainly VFR conditions are expected to prevail across all
terminals during the next 24 hours. SCT-BKN cigs btw FL035-080 will
continue across PR today. Light and variable winds will continue
thru the morning hours, increasing 8-12 kt due to sea breeze
variations aft 15z.

&&

.MARINE...Gentle to light easterly to northeasterly winds at 5 to
10 knots are expected today across much of the local waters. Seas
are generally 4 feet or less and will continue until Thursday. Another
northerly swell is forecast to arrive on Thursday morning.
Hazardous conditions are expected on Thursday for the offshore
Atlantic waters. Seas are expected up to 8 to 10 feet are from
Thursday onwards. For beachgoers, there is a moderate risk of rip
currents for beaches of northern, northwestern and northeastern
Puerto Rico, including, Vieques, Culebra, and the US Virgin
Islands.


&&

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

$$

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

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
504 AM AST Wed Mar 8 2023

.SYNOPSIS...Mainly fair weather conditions are expected today
across much of the area. In the afternoon hours, shower
development is possible across southeastern of Puerto Rico.
A series of northerly swells will promote hazardous marine and
coastal conditions beginning Thursday morning into the weekend.


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

A col developing over the northeastern Caribbean waters will promote
light steering winds with a westerly component today. Precipitable
water values (PWAT) are forecast to remain under seasonal values at
less than 1 inch until early Thursday. The limited available low
level moisture in combination with diurnal and local effects, may
trigger shower development over southeastern Puerto Rico this
afternoon. Across the USVI, little to no rainfall is expected today
and on Friday. In general, maximum temperatures will be in the mid
80s today.

Weather conditions will change on Thursday as a cold front sink
southwards over the Atlantic waters into the Caribbean. PWAT is
expected to increase between 1.25-1.50 inches throughout the day
with the frontal passage. Therefore, cloudiness and showers will
increase across the islands. Ponding of water in roads and in poor
drainage areas is possible with these showers. Moderate to locally
fresh northerly winds are expected following the front. Drier air
and fair weather conditions return on Friday.
&&

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

A seasonal weather pattern is expected this weekend as dry air aloft
persists and low-level moisture content will remain at below normal
to near normal levels. Therefore, mainly fair weather conditions
with a few isolated showers are expected during the weekend.

A series of strong surface lows exiting the northeastern U.S.into
the north Atlantic will help to gradually shift the low-level
winds from an easterly flow into a southerly component throughout
the long-term period. Wind speeds are also expected to diminish
across the northeastern Caribbean. By Monday into Tuesday, the
southeasterly wind flow will advect fragments of an old frontal
boundary from the Caribbean waters across the islands. This will
promote an increase in clouds and isolated to scattered showers
mostly over the southern/southeastern coastal areas of the islands
during night and morning hours with a few showers developing over
the Cordillera Central in the afternoon. Minimal rainfall
accumulations can be anticipated with this activity.

By midweek of next week, model guidance continues to suggest the
approach of a polar trough and associated surface frontal boundary
from the northwest. This will enhance moisture content with an
increase of cloud coverage and showery weather over the islands.

&&

.AVIATION...
(06Z TAFS)
Issued at 444 AM AST Wed Mar 8 2023

Mainly VFR conditions are expected to prevail across all
terminals during the next 24 hours. Winds up to 10 kt with a
westerly component expected through the period.

&&

.MARINE...

Mariners can expect seas up to 5 feet today across the local
waters with light to gentle westerly winds. A dangerous long-
period northerly swell will deteriorate marine and coastal
conditions beginning on Thursday. Therefore, a Small Craft
Advisory is in effect for the offshore Atlantic waters with the
possible addition of other marine zones into the advisory later
today. A second pulse of another long period northeasterly swell
will continue the hazardous conditions Saturday and Sunday. A High
rip current risk is in effect for some of the north-facing
beaches of Puerto Rico.


&&

.SJU WATCHES/WARNINGS/ADVISORIES...
PR...High Rip Current Risk from this evening through Sunday evening
for PRZ001-002-012.

High Rip Current Risk through Sunday evening for PRZ005-008.

VI...High Rip Current Risk from this evening through Sunday evening
for VIZ001.

AM...Small Craft Advisory from 8 AM Thursday to 8 PM AST Sunday for
AMZ710.

&&

$$

SHORT TERM...DS
LONG TERM....CVB
AVIATION...DS

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
357 AM AST Thu Mar 9 2023

.SYNOPSIS...Some showers associated with a cold front will reach
the local islands later today. This shower activity will be light
and short lived as the weak front moves across Puerto Rico and the
U.S. Virgin Islands. Long period swell will create large breaking
waves and dangerous rip currents especially across the Atlantic
beaches over the next several days. Drier and stable conditions
will return on Friday and will likely persist over the weekend.

&&

.SHORT TERM...Today through Saturday...
The barometric col east of the area will persist through at least
Friday promoting light steering winds with a northwesterly and north
component today and tomorrow, respectively, across the local
islands. Precipitable water values are expected to increase between
1.20 to 1.50 inches as the remnants of a cold front sink southward
and crosses the islands today. This surge of moisture along with the
combination of diurnal heating and local effects may aid in cloud
and shower development over northern coastal areas during the
morning hours and across interior and southeastern Puerto Rico this
afternoon. Some showers will also affect the U.S. Virgin Islands,
mostly St. Thomas and St. John. However, minimal rainfall
accumulations are expected with the crossing of the frontal
boundary.

Fair weather conditions will return on Friday and remain through
Saturday as drier air behind the cold front settles over the
northeastern Caribbean. Little to no rain is expected for the rest
of the short term period. Light and variable winds will also persist
through Saturday.

&&

.LONG TERM...Sunday through Friday...
Potent low pressure over the North Atlantic will disrupt the trade
wind flow across the local area late in the weekend. That deep
layer low pressure will not induce shower development across the
northeast Caribbean because it will remain far to the north. The
subequatorial high pressure will keep the conditions fairly dry
and stable Sunday and Monday. However, moisture will start to pool
again over the local region between Tuesday and Wednesday as a
weak high pressure develops east of the Leeward Islands, bringing
the remnants of an old frontal boundary over Puerto Rico and the
U.S. Virgin Islands. The trade wind flow will become southeasterly
promoting additional moisture advection by mid week. This will
likely sustain scattered showers across all local islands.

Late next week another low pressure over the north Atlantic will
push a front across the Greater Antilles. Operational models
suggest more organized convection with this front crossing the
islands between Thursday and Friday. This feature will likely
bring numerous showers at times across Puerto Rico and the U.S.
Virgin Islands. On Saturday, a surface high pressure behind the
front will bring drier conditions to the islands. These dry and
stable conditions behind the front will be short-lived as the high
pressure moves eastward bringing fragments of the frontal boundary
over the area late in the weekend.

&&

.AVIATION...(06Z TAFS)
Mainly VFR conditions expected to prevail across all terminals. A
cold front will move SSE promoting SHRA activity after 09/10z.
SCT- BKN cigs btw FL025-060 can be expected during this period.
Brief MVFR conditions are possible for TJSJ/TIST/TJBQ terminals.
Expect calm to light/vrb winds thru most of the fcst period, but
with a WNW component. Sea breeze variations could enhance winds
around 10-15 kts btwn 09/13-20z.

&&

.MARINE...A series of strong surface lows exiting the northeastern
U.S. will keep the swell action across the north Atlantic waters
through next week. A long-period northerly swell will deteriorate
marine and coastal conditions today and Friday. A second pulse of
another long period northeasterly swell will extend the hazardous
conditions Saturday onward. Then, a third pulse of long period
swell from the NNW will reach the local waters early next week.
In summary, marine conditions will be hazardous over the next
several days especially across the Atlantic Waters and Caribbean
Passages.

&&

.FIRE WEATHER...Wildfires have been reported over the western
third of Puerto Rico in the last couple of days. The passage of a
weak frontal boundary today will not produce significant rainfall
over these areas to alleviate the current situation. Today, RH
will remain above critical levels, but tomorrow are forecast to
drop again around 40% in the south and southwestern Puerto Rico
as well as Vieques. Light to moderate winds will prevail across
the local region over the next few days.

&&

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

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

High Rip Current Risk through Sunday evening for PRZ010.

High Surf Advisory from 6 PM this evening to 6 PM AST Sunday for
PRZ010-012.

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

High Surf Advisory from 6 PM this evening to 6 PM AST Sunday for
VIZ001.

AM...Small Craft Advisory from 8 AM this morning to 8 PM AST Sunday
for AMZ711-723.

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

Small Craft Advisory from 2 AM Friday to 8 PM AST Sunday for
AMZ716-742.

&&

$$

SHORT TERM/AVIATION...CVB
LONG TERM/MARINE/FIRE WEATHER....ER

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
522 AM AST Fri Mar 10 2023


.SYNOPSIS...
Issued at 441 AM AST Fri Mar 10 2023

A long-period north-northwesterly swell will maintain hazardous
coastal and marine conditions today. A second pulse of long-period
northeasterly swell will extend the dangerous situations
throughout the weekend across the Atlantic Coastlines. Expect
breezy conditions today (mainly in the northern sections of the
islands), pushing fragments of clouds and isolated showers across
the islands. A mixture of sunshine and clouds with the typical
temperatures for March will prevail through the weekend, but winds
will weaken.

&&

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

The frontal boundary is currently south of Puerto Rico with
fragmented clouds and showers mostly concentrated over the Caribbean
waters and St. Croix. This patch of clouds and shower will continue
moving southward in the next couple of hours. An area of confluence
behind the frontal boundary is promoting breezy wind conditions,
mostly affecting the northern coastal regions of the islands, and is
expected to persist throughout the day. The northerly winds will
push fragments of moisture towards the local islands supporting
isolated showers at times, mostly over northern/northeastern coastal
areas during morning hours and later developing over the
southern/southeastern slopes of Puerto Rico in the afternoon. But
for the most part, fair weather conditions is anticipated with
minimal rainfall accumulations. A similar weather pattern with
lighter winds is forecast for Saturday.

For Sunday, weather conditions will be even drier and stable with
little to no rain over the local region. Winds will remain light and
variable as a potent low pressure over the North Atlantic and
surface high pressure across eastern Atlantic induce a barometric
col across the northeastern Caribbean.

&&

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

A strong surface low pressure moving northeastward across the
North Atlantic will disrupt the trade wind flow across the
Northeast Caribbean through Monday afternoon. The frontal boundary
associated with that low, will remain off to the north of the
region, keeping a drier air mass over Puerto Rico and the U.S.
Virgin Islands on Sunday. Moisture content will pool from the
Caribbean Tuesday and Wednesday as a weak high pressure develops
east of the Leeward Islands. Under this weather pattern, it is
possible to observe scattered showers around mid-week.

Another surface low forecast to exit the Eastern Seaboard will
push its associated cold front over the Northeast Caribbean
Thursday through Friday, promoting unsettled weather conditions.
Exist the possibility of observing better convection and possible
urban flooding during that period. Moisture content may continue
above normal for Saturday as the surface high pressure preceding
the front maintain moisture pooling over the region. However, some
discrepancies between today's and yesterday's runs are evident;
therefore, confidence in this possibility is low.

&&

.AVIATION...
(06Z TAFS)
Issued at 441 AM AST Fri Mar 10 2023

Mainly VFR conditions expected to prevail across all terminals. SCT-
BKN cigs btw FL025-060 can be expected as cold front over the
Caribbean waters continues moving southward. Therefore, brief MVFR
conditions are possible for TJSJ/TIST/TJBQ/TISX terminals thru
10/14z. Sea breeze variations could enhance winds around 10-15 kts
and higher gusts btwn 10/13-20z with a WNW component.

&&


.MARINE...
Issued at 441 AM AST Fri Mar 10 2023

A long-period north-northwester swell will maintain hazardous
marine and coastal conditions today. Mariners can expect wave
heights between 7 and 10 feet with a period between 10 and 14
seconds. A second pulse of another long period northeasterly
swell will extend the hazardous conditions Saturday onwards.

Marine conditions will be extremely hazardous over the next
several days (including the weekend), especially across the
Atlantic Waters and Caribbean Passages. Therefore, we have in
effect a Small Craft Advisory.

Coastal conditions along the Atlantic Coastline are also
hazardous. Therefore, we have in effect a Coastal Flood Advisory,
a High Surf Advisory, and a High Rip Current Risk Statement.

&&

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

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

Coastal Flood Advisory until 6 PM AST this evening for PRZ001-
002-005-008.

High Rip Current Risk through Saturday afternoon for PRZ011.

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

High Surf Advisory until 6 PM AST Sunday for VIZ001.

High Rip Current Risk through late tonight for VIZ002.

AM...Small Craft Advisory until 8 PM AST Sunday for AMZ711-712-716-
723-741-742.

Small Craft Advisory until 8 AM AST Saturday for AMZ726.

&&

$$

SHORT TERM/AVIATION...CVB
SYNOPSIS/LONG TERM/MARINE....CAM

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
556 AM AST Sat Mar 11 2023


.SYNOPSIS...

Generally fair weather is expected through the weekend, with only
patchy moisture likely into at least Monday. A few showers are still
possible, but shower activity will be limited. Increasing shower
activity is expected Tuesday and Wednesday, with another frontal
boundary likely to result in our wettest day on Thursday.

Breaking wave heights of up to around 12 to 16 feet are anticipated
for most north-facing beaches across the islands. Rip currents,
dangerous surf, and coastal flooding will be concerns. Seas of up to
8 to 10 feet are expected across the waters. Anyone planning to
partake in activities in and around the water should remain aware of
conditions, both forecast and current.

&&

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

Two very weak fronts are playing a role in the weather across the
area for the next several days. One is southeast of the area and the
other is fading over the area. The total precipitable water product
from GOES is also showing faint banding for the two fronts. One
other feature is readily apparent and that is the moisture being
pulled out of Venezuela ahead of the first front that passed. This
will play a role later in the long term forecast. Until then,
weather conditions will be dominated by strong capping today. On
Sunday the model begins to erode the cap, but at the same time it
also begin drying the marine layer from the top. It is not clear why
it is doing so except that the cold front is decaying while cool air
continues to advect over the area. This still leaves the local area
pretty dry today and Sunday. The extremely light winds at 850 mb
over the area begin to turn southerly on Sunday night and Monday
which will bring back the moisture associated with the previous
front and moisture which has been newly gathered from a warm
Caribbean Sea and advected out of Venezuela yesterday and today.

&&

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

Relatively dry air is expected to be in place over much of the
islands on Tuesday morning. However, the remnants of an old frontal
boundary is forecast push northward from over the Caribbean to bring
moisture to the islands by around midday on Tuesday; for areas in
the northeast, moisture may not arrive until the afternoon. Over the
islands, the most significant moisture is forecast to affect
southern and western parts of the region. Moisture will then linger
through Wednesday, decreasing through the day into the night, though
near-normal moisture is still expected for Wednesday night into
Thursday. A modest decrease in moisture may also be seen early on
Thursday.

The wettest portion of the long-term period will likely be late
Thursday into Thursday night. A frontal boundary is forecast to
arrive over the islands during the day on Thursday, passing over the
islands Thursday night. An increase in moisture and instability in
the low- and mid-levels will accompany this frontal boundary. As
such, widespread shower activity is likely, particularly during
the night.

There may be some lingering moisture on Friday, but overall, much
drier air will push into the region behind the front. Moisture is
expected to be limited to generally below around 800 hPa, with this
holding true through Saturday into Sunday, as well. Some patchy
moisture is possible Saturday, more likely later in the day and into
the night, with patchy moisture expected for Sunday, which may help
support a few showers over the area.

&&

.AVIATION...
(06Z TAFS)

Mainly VFR conditions are expected to prevail. SCT-BKN cigs btw
FL025-060 near the mountains and hills of both PR and the USVI can
be expected as moist air behind the cdfnt conts to push thru. Sea
breeze variations fighting weak and variable flow will produce
variable winds around 6-12 kts and higher gusts btwn 11/13-20z.

&&

.MARINE...

Seas remain hazardous or near hazardous likely through much of the
next week; coastal conditions will as well. Seas of up to around 8
to 10 feet are expected through the weekend, under the effects of a
northerly swell. Breaking wave heights of around 12 to 16 feet, and
occasionally higher, are expected for most north-facing beaches
across the islands.

&&

.SJU WATCHES/WARNINGS/ADVISORIES...
PR...Coastal Flood Advisory until 6 PM AST Sunday for PRZ001-002-005-
008-010-012.

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.

High Rip Current Risk through Sunday afternoon for PRZ011.

High Surf Advisory until 6 PM AST this evening for PRZ013.

VI...Coastal Flood Advisory until 6 PM AST Sunday for VIZ001.

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

High Surf Advisory until 6 PM AST Sunday for VIZ001.

High Surf Advisory until 6 PM AST this evening for VIZ002.

AM...Small Craft Advisory until 8 PM AST Sunday for AMZ711-712-716-
723-741-742.

Small Craft Advisory until 2 AM AST Sunday for AMZ726.

&&

$$

SHORT TERM...WS
LONG TERM....CS
AVIATION...WS

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
517 AM AST Sun Mar 12 2023

.SYNOPSIS...

Generally fair weather is expected into the workweek. Moisture is
expected to increase Tuesday into Wednesday, resulting in an
increase in shower activity, followed by the traversal of a frontal
boundary over the region, bringing a further increase in showers.
After that, fair weather is expected to return on Friday.

A northerly swell is causing hazardous marine and coastal conditions
for much of the local area. Seas of up to 8 to 10 feet are expected,
especially for the offshore Atlantic waters, today. Gradual
improvement is anticipated, and a brief break in hazardous marine
conditions is expected for Monday. However, conditions along north-
facing beaches is expected to remain hazardous. Another pulse of
swell is forecast to arrive by Tuesday, bringing renewed hazardous
conditions.

&&

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

Strong low pressure about 750 miles east of the coast of Maryland
will move rapidly east across the Atlantic ocean with a cold front
trailing and stalling at about 22 degrees north latitude. High
pressure almost 1300 miles west of the Canary Islands extends across
the local area, creating southerly winds. As the high drifts to the
north it will carry the ridge with it, and bring surface flow
more from the east southeast. This will carry some moisture with
it, which will increase the chance of showers, but moisture
remains shallow, and shower chances will only increase to
scattered in eastern Puerto Rico during the overnight and morning
hours and in western Puerto Rico and along the Cordillera Central
during the afternoons each day. Showers will increase in coverage
and likelihood each day of the short term period. The depth of the
moist layer will increase from 850 mb today to just over 700 mb
early Tuesday morning. On Tuesday the GFS is expecting a layer of
95 percent relative humidity around 8200 feet to move in over the
area fairly suddenly from air being pulled across the Caribbean
from western Colombia. The models favor this with higher PoPs over
the interior of Puerto Rico (not so much over the U.S. Virgin
Islands), but the time height section reveals that the moisture is
limited in depth, and though it becomes higher during the day, it
does not extend much below 700 mb by the end of the day. This
could indicate a heavy layer of altocumulus, which would filter
the sunlight reaching the surface, and cut off most shower
development. Therefor have limited the PoPs in the forecast for
Tuesday from NBM values, also remembering that we are still in a
fairly dry airmass overall that has been mostly over-forecast by
the GFS and the NBM.

The southerly flow will bring warmer temperatures to the north coast
today through Tuesday and many areas around the Greater San Juan
Metropolitan area may reach the upper 80s by Tuesday or Wednesday.

&&

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

By Wednesday morning, moisture will be over much of the local
islands, especially in the southwest, pushing northward, and then
northeastward by Wednesday night. Moisture will reach into the mid-
levels, though a layer of dry air is expected to linger between
around 850 and 750 hPa. Showery weather is likely on Wednesday,
though significant convective development is unlikely. A brief
period of slight drying is expected on Thursday morning, ahead of a
frontal boundary moving in from the north/northwest. A small
increase in moisture ahead of the boundary is expected during
midday/early afternoon, with a significant increase in moisture,
in terms of both overall amount and its vertical extent, is
expected Thursday evening into Thursday night. Widespread shower
activity is expected for Thursday evening into Thursday night.
Moisture is expected to linger Friday morning, but only briefly,
with much drier air moving in behind the front, resulting in a
significant decrease in shower activity. Generally fair weather is
then expected through the weekend, though some patchy moisture
will maintain a few isolated showers. Late Sunday night through
Monday, what is left of the aforementioned front will make a
return trip, dragged through the area out of the east/southeast.
As such, shower activity will increase over the area during this
time, persisting through the day on Monday. However, the amount of
moisture - and showers - is not expected to be as high as for
late Thursday night.

&&

.AVIATION...
(06Z TAFS)

VFR conditions are expected to prevail. SCT-BKN cigs btw FL025-060
near the mountains and hills of both PR and the USVI. Sea breeze
will predominate with overall flow becoming more southerly today.
Expect winds of 6 to 12 knots with hir gusts alg the coasts. Some
MVFR may be experienced near TIST due to cld formation over the
higher points othw no sig impacts to navigation is expected. Winds
btwn FL290-535 are greater than 50 knots. Best winds of 80-85 knots
are WSW arnd FL400.

&&

.MARINE...

The swell is forecast to gradually subside later today into
tomorrow. For now, however, buoys indicate it is maintaining
hazardous conditions for the local waters. Buoy 41049 has shown a
marked decrease in swell height, from 10.5 to 12 feet midday
yesterday to around 5 to 6 feet in the last several hours, though
the swell period remains about the same at around 14 to 15 seconds.
This does indicate, though, that swells of around 7 to 9 feet at 16
to 17 seconds are likely to affect the waters through at least
midday today. At buoy 41043, swell heights have decreased modestly,
to 9 to 10 feet, down from around 10 to 12.5 feet around midday
yesterday.

Though the swell decays, it never quite goes away. Because of this,
we retain dominant periods of at least 13 to 14 seconds for much of
the week. And because of this, breaking wave heights will remain
quite high. Conditions are likely to meet High Surf Advisory
conditions into at least Monday, with model guidance suggesting that
it could last through the week. Considering the veritable parade
of strong lows marching across the Atlantic, with all of them
showing a propensity for strengthening south of Nova Scotia and/or
Newfoundland (which is a quite reasonable scenario for this time
of year), it is certainly reasonable to consider that these
dangerous conditions may persist for several more days still.

Seas will subside below hazardous criteria on Monday, with model
guidance backed up by data from buoys, such as was mentioned with
buoy 41049. Breaking wave height is also expected to decrease,
though still remaining around 10 feet for many of the north-facing
beaches across the islands. Another pulse of swell is forecast to
arrive Monday night, though, resulting in further hazardous seas and
additional dangerous surf conditions.

Basically, this is yet another great week to stick to the Caribbean
and south-facing beaches. If you do have interests in the local
Atlantic waters and passages, or along the north-facing coasts of
the local islands, you should remain aware of current and forecast
conditions and exercise caution in and around the water.

&&

.SJU WATCHES/WARNINGS/ADVISORIES...
PR...Coastal Flood Advisory until 6 PM AST this evening for PRZ001-
002-005-008-010-012.

High Rip Current Risk through Monday afternoon for PRZ001-002-
005-008-010-012-013.

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

High Rip Current Risk through this afternoon for PRZ011.

High Surf Advisory until 6 PM AST this evening for PRZ013.

VI...Coastal Flood Advisory until 6 PM AST this evening for VIZ001.

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

High Surf Advisory until 6 PM AST Monday for VIZ001.

High Surf Advisory until 6 PM AST this evening for VIZ002.

AM...Small Craft Advisory until 8 AM AST Monday for AMZ711-712-716-
723-741-742.

Small Craft Advisory until 8 PM AST this evening for AMZ726.

&&

$$

SHORT TERM...WS
LONG TERM....CRS
AVIATION...WS

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
557 AM AST Mon Mar 13 2023

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

.SYNOPSIS...
Issued at 521 AM AST Mon Mar 13 2023

A fresh pulse of swell will enter the Atlantic waters tonight and
build through Tuesday. A second pulse will come in on Thursday
night and persist well into the weekend. Some moisture will move
in from the southwest today and Tuesday and will be met on
Thursday by a cold front advancing from the northwest. Drier
weather is expected for the weekend and beyond, but scattered
showers will continue in the normal diurnal pattern.

&&

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

Generally fair weather conditions should prevail today, as a mass of
relatively dry air moves across the region. Satellite derived
precipitable water (PWAT) values show below to around an inch of
columnar moisture over the islands with most available moisture
being restricted to below 700 mb with dry mid levels. As a surface
high pressure continues to affect the forecast area, winds will
become more easterly, before gradually veering to become more
southeasterly through midweek. These winds will promote somewhat
warmer temperatures over the region. Afternoon convection remains
a possibility over areas of the interior due to diurnal and local
effects. Current model guidance indicates an area of more humid
air, with normal to above normal PWAT values, filtering into the
region from the Caribbean waters and pushing northward by tonight
and into tomorrow, Tuesday. With the trade wind cap also eroding,
moisture will reach the mid-to-upper levels through midweek. This
increase in moisture will result in increased shower activity and
generally showery weather across the region, as the moist air
mass persists over the islands Tuesday and Wednesday. Afternoon
shower development will also affect areas of the interior and
western Puerto Rico due to diurnal and local effects. Although dry
air will filter into the area from the south on Wednesday night,
moisture related to a frontal boundary will approach the area from
the northwest to start the long term forecast period.


&&

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

Clouds and scattered showers will remain on Thursday as a cold
front from the northwest invades the local area. This will provide
the conditions necessary to drive better shower activity
Thursday and Friday, even while columnar moisture is decreasing
dramatically. Drier air will move in at 700 mb immediately
following and persist through Tuesday, shallow moisture will
linger Friday and Saturday and gradually fade as much drier air is
introduced. Nevertheless some patches of moisture persist and
will allow shallow showers to persist into the weekend. Then most
of the low level moisture will become too shallow to produce
anything more than isolated showers and light rain Monday and
Tuesday.

At upper levels the forecast area will remain in mostly westerly
flow with high pressure firmly in place to the south until a
strong trough passes to the north on Friday morning to both augment
the showery conditions and then weaken them later and into the
weekend. High pressure forms over the west-central Caribbean as a
sharp trough forms over the ABC Islands to our southeast Monday
into Tuesday. Nevertheless the dominant effect will be toward
fair weather beginning next week.

After the front passes, mid levels will again be completely dry
and high pressure will ridge out of the western Caribbean to our
northeast.

&&

.AVIATION...
(06Z TAFS) Issued at 521 AM AST Mon Mar 13 2023

VFR conditions will continue for all of the local terminals
today. Winds will increase to around 5-10 mph under a generally
easterly flow with sea breeze variations. No significant impact to
terminals from any brief passing shower activity. Moisture will
start filtering into the area from the Caribbean waters late
tonight and into tomorrow.

&&

.MARINE...
Issued at 521 AM AST Mon Mar 13 2023

As winds have been relatively light, marine conditions have been
settling. Seas at both the inner and outer buoy have dropped to
between 4 and 5 feet even though swell periods have remained
relatively long at 11-14 seconds, showing the distant source of
the agitation. Strong waves will enter the forecast area later
tonight and create conditions hazardous to small craft as well as
beach-goers due to an on-going high risk of rip currents and high
surf that will fade in most areas today but return on Tuesday. A
second pulse will arrive on Thursday night and continue into the
weekend with similar conditions.

&&

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

High Surf Advisory until 6 PM AST this evening for PRZ001-002-
008-010-012.

High Surf Advisory until 6 PM AST Wednesday for PRZ005.

High Rip Current Risk through this afternoon for PRZ013.

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

High Rip Current Risk through this afternoon for VIZ002.

High Surf Advisory until 6 AM AST early this morning for VIZ001.

AM...Small Craft Advisory from 8 PM this evening to 8 AM AST Saturday
for AMZ711.

Small Craft Advisory from 8 AM Tuesday to 8 PM AST Wednesday for
AMZ712-723.

Small Craft Advisory from 8 AM Tuesday to 2 PM AST Wednesday for
AMZ716.

&&

$$

SHORT TERM/AVIATION/PUBLIC...MRR
LONG TERM/FIRE WEATHER....WS

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
556 AM AST Tue Mar 14 2023

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

.SYNOPSIS...
Issued at 505 AM AST Tue Mar 14 2023

A recent pulse of swell will peak this morning along our coasts.
A second, stronger pulse will come in on Thursday night and
persist well into the weekend. Some moisture has moved in from the
south overnight and will bring a few more showers to the interior
of Puerto Rico and the local waters this afternoon. 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 Thursday

A surface high pressure over the central Atlantic will maintain a
southeasterly wind pattern across the Islands. Under this east-
southeast wind pattern influence, patches of Caribbean moisture will
reach the local islands, increasing the water content across the
region. According to the satellite derived imagery, Pwat values
across the Caribbean sea are around 1.5 inches, which is near or
slightly above climatological normals. This pattern will continue
to result in cloudiness across the region with some afternoon
showers across the northwestern quadrant of Puerto Rico. Minimal
rainfall accumulations are expected today. The latest model
guidance agrees with a more unstable and wet pattern from late
Wednesday into Thursday. At the surface, an increase in moisture
from a frontal boundary moving southward into the region is seen
and some instability aloft will be provided by an upper-level
trough moving just north of the area. As the front approaches, a
reduction in the pressure gradient will create more light and
veering winds. This wind flow will enhance the development of
shower activity in the afternoon hours across the interior
sections of Puerto Rico. Regardless of the increase in showers,
rainfall accumulations will not be sufficient for any flood threat
except for some localized ponding of water in roadways where the
heaviest activity occurs.

Daytime temperatures will warm slightly across the north-central
sections due to the southeasterly component.

&&

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

The cold front will arrive on Thursday night. Good vertical motion
will begin on Thursday and moisture will deepen on Thursday night.
Drier air will spread into the area above 6 or 7 thousand feet on
Friday, but a moist layer will remain through the end of the
period. It will thin, however, as clouds erode and provide some
heating from the ground. Showers will likely spread over most of
Puerto Rico and the other islands on Thursday night and Friday
morning, continue on the windward side Friday afternoon through
Saturday morning and then gradually diminish through Wednesday.

By Friday, the upper level trough will have moved to our northeast
with high pressure across Panama. The sub-tropical jet will hover
over or just north of the area until a second and weaker trough
crosses through on Sunday. The ridge to our west will finally
arrive on Wednesday, but the trough that moved over the southern
Windward Islands on Monday will remain in place causing flow to
become more northerly over the local area.

Mid levels will become quite dry after Friday and remain so beyond
the end of the period, again limiting most shower activity.

&&

.AVIATION...
(12Z TAFS)
Issued at 505 AM AST Tue Mar 14 2023

VFR conditions will prevail for all the TAF sites during the period.
Winds will remain VRB at 5 kts or less until 14/14Z, increasing to
12 kts from the E-SE with sea breeze variations. Some VCSH is
possible at TJPS & TISX around 14/23Z-1503Z with the approach of
cloudiness. Winds will revert to VRB around 14/22Z. Maximum winds
W 60-70 knots btwn FL325-440, strongest at FL370.

&&

.MARINE...
Issued at 505 AM AST Tue Mar 14 2023

Seas at the outer buoy (41043) peaked around midnight at nearly 10
feet and 17 seconds and have now diminished to just above 7 feet
at 13 seconds. As of 5:00 AM AST seas were approaching 7 feet at
14 seconds. Some of the highest waves will be arriving on the
north coasts of Puerto Rico and the northern U.S. Virgin Islands
this morning and will fade tonight. Unfortunately, marginally
hazardous seas will persist through Wednesday night. Another
stronger swell will enter our Atlantic waters on Thursday night
with seas up to 12 feet expected. Seas are expected to remain
hazardous with small craft advisories not ending before Monday.
The local Caribbean waters south of Puerto Rico will remain the
most favorable for navigation.

High surf will impact the area today and tonight--generally between
10 to 12 feet. High surf will subside to just below thresholds
for all but the northwest zone of Puerto Rico before hazardous
surf is again encountered beginning Thursday night. This time up
to 14 foot breaking waves are expected.

&&

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

High Surf Advisory until 6 AM AST Thursday for PRZ001-002-005-
010-012.

High Surf Advisory until 8 AM AST Saturday for PRZ008.

High Rip Current Risk through late Friday night for PRZ011-013.

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

High Surf Advisory until 6 PM AST Wednesday for VIZ001.

AM...Small Craft Advisory until 8 AM AST Saturday for AMZ711-742.

Small Craft Advisory until 8 PM AST Wednesday for AMZ712-723.

Small Craft Advisory until 2 PM AST Wednesday for AMZ716.

Small Craft Advisory from 8 PM this evening to 8 AM AST Saturday
for AMZ741.

&&

$$

SHORT TERM/AVIATION...LIS
LONG TERM/FIRE WEATHER....WS
PUBLIC...RVT