Caribbean - Central America Weather

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
503 AM AST Sat Feb 26 2022

.SYNOPSIS...

There remains a high risk of rip currents for beaches of northern
Puerto Rico, as well as for beaches of St. Croix, Culebra,
Vieques, and northwestern St. Thomas.

Patchy moisture will help to sustain shower activity over the
region today into tomorrow. Increasing moisture is expected for
tomorrow into Monday, increasing shower activity. Another increase
in showers is expected for late in the next work week, but
forecast confidence is low at that point.

&&

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

Surface high pressure ridge north of the region and a broad induced
surface trough extending across the region from the northeast, will
maintain a moderate northeasterly wind flow today. The winds are
then expected to become more east southeast by Sunday into Monday as
the trough crosses the region.

Occasional patches of shallow moisture embedded in tradewinds will
bring periods of passing showers across the local waters and
windward sections of the islands from time to time during the rest
of the morning. Some showers may move inland over sections of the
east interior, but no significant rainfall is expected. Afternoon
showers are forecast to develop mainly over parts of the central
interior and southwest Puerto Rico steered by the prevailing
northeast wind flow. Brief periods of moderate to locally rains can
be expected but of short duration. The U.S. Virgin Islands can
expect lesser amounts of afternoon showers and should be focused
mainly on the west-end or just downwind of the islands. Overall,
mostly fair weather skies and pleasant temperatures can be expected
elsewhere during the rest of the day.

By Sunday and Monday, the broad surface trough previously mentioned
will cross the region and bring a gradual increase in low level
moisture as it moves westward and winds become more southeasterly.
This will favor slightly warmer daytime temperatures and also
increase the potential for early morning showers across the north
and east coastal areas of the islands. During each afternoon, there
will be a better chance for enhanced convection especially across
the central and west to northwest sections of Puerto Rico. The best
chance for increased shower activity across Puerto Rico including
the U.S. Virgin Islands will be by Sunday afternoon and continuing
through Monday, as additional trailing moisture is expected to cross
and converge over the islands in the prevailing southeasterly wind
flow. As such, the potential for minor urban and small stream
flooding in isolated areas will increase, mainly over western
Puerto Rico during the afternoon hours where periods of locally
heavy rains will be possible. Minor ponding of water on roads and
in poor drainage areas will also be possible in isolated areas
around the San Juan metro, as well as in some of the U.S. Virgin
Islands. So far most of the shower activity should be brief with
widespread rainfall accumulations not expected across the islands
at this time based on the most recent model guidance and the
overall low and upper level weather pattern.

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

Patchy moisture is expected to continue over the region into
midweek. This is partially from a disturbance making its way across
the region from the east. The bulk of the moisture is expected to be
pulled away to the north by a frontal boundary that will remain well
north of the region. As such, Tuesday and Wednesday are likely to
have fairly typical weather for this time of year, with patchy
moisture supporting shower activity. Aloft, a mid- to upper-level
ridge is expected to remain dominant over the area, maintaining
stability and inhibiting significant development. Winds are expected
to be relatively weak, with a slackening of the pressure gradient
associated with the frontal boundary; any showers that develop will
likely be slow-moving and could lead to locally high precipitation
amounts. Confidence in the forecast to that point is medium, given
uncertainties with the disturbance and its interaction with the
frontal boundary. Decent stability and moisture levels to near-
normal, however, are fairly likely.

Late in the workweek, there could be some modest weakening in the
ridge at mid- to upper-levels by a low well to the east, off the
coast of western Africa. Additionally, the back end of the
disturbance is expected to make its way into the CWA, which will
bring a surge in moisture to the region. The modest increase in
instability and increase in moisture will likely result in an
increase in shower activity across the region. There is little model
agreement here, however, and there is substantial variation between
model runs. Considering this and the fact that there are multiple
systems in play, the confidence in the forecast to this point is
low. And will continue to be low through the end of the forecast
period.

Gradual drying is expected for the next weekend. There could be a
little more instability at the end of that weekend, but certainty is
low. Additionally, the decreasing moisture will likely inhibit any
real increase in shower activity that could result from that. As
such, decreasing shower activity is expected for next Saturday into
Sunday.

&&

.AVIATION...

VFR conds will prevail at all terminals,SCT ocnl BKN cld lyrs n r
FL025...FL050 and wdly sct SHRA en route btw islands and ovr
regional waters. VCSH at TJSJ/TISX/TIST til 26/13Z. Mtn top obscr
ovr Ern PR due to passing SHRA and low clds. Sfc winds calm to
lgt/vrb bcmg E-NE at 10-18 kts with hir gusts and sea breeze
variations aft 26/14Z. L/lvl wnds fm ENE 15-20 kts BLO FL150 then
backing and bcmg fm NNE ABV while incr w/ht. No sig operational wx
impacts attm.

&&

.MARINE...

There is a lingering northeasterly swell in the local waters.
Moderate winds will maintain some chop across the waters and combine
with the swell to keep seas at up to 6 feet for the Atlantic waters
and local passages today. As such, operators of small craft are
urged to exercise caution. At buoy 41043, seas have subsided
slightly, to around 7.2 to 7.5 feet in the last couple of hours;
wave direction has been observed as east-northeasterly, so it is
likely that not all of that energy is reaching the local waters. At
the nearshore buoys, wave heights have been reported as 5 feet or
less. Because of this, seas of 6 feet or less is reasonable for the
local waters.

There is a high risk of rip currents for beaches of northern Puerto
Rico, Culebra, Vieques, northwestern St. Thomas, and northern and
eastern St. Croix.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 83 72 85 74 / 30 50 40 50
STT 84 73 83 75 / 20 40 40 30

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
459 AM AST Sun Feb 27 2022

.SYNOPSIS...

Increasing shower activity is expected, with increasing moisture and
decreasing stability aloft, for the start of the work week. By
around midweek, activity will likely decrease again, though another
increase is forecast near the end of the week.

There remains a high risk of rip currents for beaches of northern
Puerto Rico and eastern St. Croix today into tomorrow.

&&

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

A mid to upper level low continued northeast of the region while an
associated trough (TUTT) sags southwestward across the northern
Leeward islands into the eastern Caribbean. This feature is forecast
to meander across the northeastern Caribbean while maintaining the
area on the subsident side of the trough axis. The ridge aloft to
hold at least through today before gradually eroding on Monday and
Tuesday, as a polar trough is forecast to sweep across the west
Atlantic just north of the region. In the meantime a broad induced
surface trough with its axis now crossing the U.S. Virgin Islands
will continue westward across the region through Tuesday. As a
result, the prevailing east northeast wind flow will gradually
become more east to southeast later today through Tuesday. An
increase in low to mid level moisture along with a gradual warming
trend is expected as the low level winds become more southeasterly.

For the rest of the morning hours, occasional patches of tradewind
moisture and showers will cross the local waters reach parts of the
U.S. Virgin Islands and the north and east coastal areas of Puerto
Rico from time to time. Widespread rainfall is not anticipated but
brief periods of moderate to locally heavy rains of short duration
will remain possible. During the afternoon and evening hours, winds
are expected to become more southeasterly along with the gradual
increase in low level moisture advection and convergence. Late
afternoon shower development is then expected to increase over the
east and central interior of Puerto Rico and eventually steer
towards the northern half of the islands including in and around the
portions of the San Juan Metro. The upper level ridge will hold in
place and therefore do not expect significant rainfall, as most of
the convective development should be suppressed. Periods of locally
heavy rains may lead to some ponding of water on roads and in poor
drainage areas during the late afternoon hours but only in isolated
areas.

Increasing low-level moisture convergence is expected on Monday
into early Tuesday. In addition, the upper ridge will erode as
the previously mentioned upper trough crosses the west Atlantic.
That said, and based on the most recent model guidance especially
the GFS, expect the best potential for increased shower activity
on Monday and during the early morning hours on Tuesday. Improving
conditions are so far forecast by Tuesday afternoon as the low
level moisture transport should diminish and the upper ridge is
expected to slowly reestablishes itself overhead. Sufficient
periods of heavy rainfall across the the islands on Monday into
early Tuesday will favor periods of urban and small stream
flooding in isolated area along the north and east section of
Puerto Rico; as well as over portions of the U.S. Virgin islands
where the heaviest rains should be during the overnight and early
morning hours. Minor ponding of water on roads and in poor
drainage areas will therefore be possible in isolated areas over
portions of the U.S. Virgin Islands.

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

A dry slot is likely to be affecting the region on Wednesday,
between pulses of moisture. A disturbance passing by the region from
east to west located to the south of the area is forecast to be
pulled apart through interaction with a frontal boundary well to the
north of the region, mitigating the amount of moisture seen from
this feature, especially through midweek. A mid- to upper-level
ridge will maintain stability over the region during this time, as
well, which will inhibit significant development. As such, a weak
advective pattern is likely for Wednesday, and fewer showers than
typical are likely.

On Thursday, additional moisture makes its way into the region.
Conditions aloft remain relatively stable, though some weakening of
the ridge is possible. During this time, some erosion of the ridge
from the east is possible, with a mid- to upper-level low churning
off the west coast of Africa. Additionally, a deep-layer polar
trough could also contribute to some erosion. It is worth noting
that despite the general lack of model consensus and the inter-run
variability, one constant has been the existence of a frontal
boundary that stays well north of the region, stalling there late
in the week; a crossing of the region by this boundary appears
unlikely. But, the erosion of the ridge aloft supported by the
trough associated with this boundary is likely to result in a
modest increase in instability into the end of the week. This will
further support an increase in shower activity. Furthermore, some
moisture convergence is likely over the region on Friday.
Increasing shower activity is therefore likely for the end of the
work week.

Drier air with some patchy moisture is expected for the weekend. The
disturbance from the east does linger south/southwest of the region,
which will help to maintain some of the moisture over the area. Even
so, a slow, gradual drying trend still appears likely. Aloft,
however, increasing instability remains possible. The GFS suggests
that the 500 hPa temperature will continue to fall through the
weekend, reaching a minimum on Sunday near -10C. If this were to
verify, it would suggest support for more development over the
region, and a potential for thunderstorms. So, lingering active
weather is possible through the weekend. Drying is likely for the
start of the next workweek, however, as instability and available
moisture both decrease.

Forecast confidence is... not great, especially after midweek, and
is definitely low by the weekend. Uncertainty is linked to the
frontal boundary that is expected to interact with a broad
disturbance over the region. Timing and magnitude of moisture could
change in either direction. And the interaction of multiple features
aloft is also uncertain, and therefore so is the forecast
instability. On the whole, it is likely that we will have a period
of enhanced activity, likely sometime near the end of the week,
couched by more typical levels of activity under an advective
pattern.

&&

.AVIATION...

VFR conditions will prevail through the forecast period. However, a
surface trough crossing the region will bring widely SCT SHRA over
the regional waters and en route between the local islands. SCT-BKN
lyrs nr FL025...FL050 with brief MVFR conds psbl at times. SFC wnds
will be calm to lgt/vrb, becoming fm E-SE btw 10-15kt with higher
gusts and sea breeze variations after 27/14z. SHRA/-SHRA fcst to
incr across the local flying area from the east, with VCSH at
TNCM/TKPK thru 27/12z, TIST/TISX btw 27/12Z-22Z and TJSJ/TJBQ
aft 27/18z.

&&

.MARINE...

Seas of up to 6 feet are possible for the local waters, mostly in
the offshore Atlantic waters, with lower wave heights elsewhere.
Winds will be generally out of the east at the surface, at up to
around 15 knots. This will maintain some chop across the waters.
There is also a lingering weak northeasterly swell in the Atlantic
waters. Very modest improvement in conditions is possible tomorrow
into midweek, but seas of 5 feet or less are still likely during
that period.

There remains a high risk of rip currents for beaches of northern
Puerto Rico and eastern St. Croix. The risk of rip currents for
nearly all other beaches is moderate, with the exception of some
beaches along the southwestern and south central coasts of Puerto
Rico.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 84 74 85 74 / 40 50 50 40
STT 83 74 83 74 / 40 60 50 30

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
525 AM AST Mon Feb 28 2022

.SYNOPSIS...

A broad surface trough will continue to cross the islands bringing
an increase in moisture across the region through at least early
Tuesday. The prevailing southeast wind flow and increasing moisture
along with low level convergence will support best potential for
shower development today into early Tuesday. Diminishing moisture
transport with lesser shower activity expected by mid-week with
warmer temperatures. A slight moisture increase is again expected
by the end of the work week as winds become light and moisture
convergence increases due to induced troughiness across the region
in response to a cold front will move into the west Atlantic and
stall northwest of the region. In the meantime the ridge aloft is
to gradually erode as a polar tough moves across the Atlantic
north of the area.

&&

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

The general forecast trend appears to be holding through the short
term period. Today is likely to be the most active day across the
islands. There is a mid- to upper-level low affecting the region,
located generally east of the area, while an induced lower-
level/surface trough is passing by the area from east to west.
Moisture is increasing across the region. Satellite estimates show
an area of increased moisture with precipitable water values around
1.5 to 1.6 inches is approaching the region from the east, and has
begun to reach the USVI this morning. The vertical extent of
moisture is likely to increase; shear and drier air above around 500
hPa will be a limiting factor, however. Because of this,
thunderstorms remain generally unlikely; they cannot be entirely
ruled out, however, especially as shear is forecast to decrease
later today. At this point, they appear more unlikely than likely,
and have therefore been left out of the forecast. Stronger and more
widespread shower activity is likely to lead to locally high
rainfall totals, and there is an increased risk of urban and small
stream flooding. This is of most concern for portions of
northwestern and interior Puerto Rico, as well as the San Juan metro
area.

A dry slot is forecast to make its way into the CWA tonight or early
tomorrow morning. Drying is expected, progressing across the region
tomorrow into Wednesday. Aloft, the ridge will re-assert itself over
the area, increasing stability. The decreasing moisture will combine
with the increased stability to result in a decrease in shower
activity. Generally fair weather is expected into midweek, though
the available moisture is still expected to support some typical
shower activity. Tomorrow afternoon, especially, there will still be
lingering moisture in the western parts of the region to sustain
afternoon convection in northwestern and interior portions of Puerto
Rico.

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

A mid- to upper-level ridge will will gradually erode by Thursday
onwards as a polar trough will cross the west and southwest Atlantic.
This in turn will destabilize the upper levels and allow a better
chance for convective development over in and around the islands,
especially during the early morning and afternoon hours.
Additionally low to mid level moisture is to increase as a weak
surface trough is forecast to develop and cross the region, thus
favoring more low level moisture convergence and better potential
for convective development through the end of the work week and
into the early part of the following weekend. This overall
scenario will therefore continue to support an increase in
enhanced shower activity with good chance for minor urban and
small stream flooding in isolated areas as well as ponding of
waters on roads and in poor drainage areas.

By late Saturday and through the rest of the weekend, patchy moisture
is expected to linger across the region as the upper trough is forecast
to shift east northeast of the region and the induced surface trough
gradually weakens. This will help to maintain sufficient moisture over
the area and therefore early morning and afternoon convection will
remain likely, but with lesser coverage. However, so far GFS guidance
continued to suggest sufficient instability aloft over the weekend
with cooler 500 hPa temperatures especially on Sunday and
consequently this would support for convective development with
potential for isolated afternoon thunderstorms mainly over the
west interior sections of Puerto Rico. By Sunday night and through
the rest of the period, a slow but gradual erosion of low level
moisture is expected as the upper ridge reestablishes and the
prevailing east to northeast winds increase along with the trade
wind cap inversion. This will result in a more seasonal weather
pattern with generally fair weather conditions expected for much
of the islands for the latter part of the period.

&&

.AVIATION...
Generally VFR conditions expected next 24 hours for all aerodromes.
However, brief MVFR cannot be ruled out, associated with VCSH/SHRA,
mostly during 28/16-28/23Z for JSJ/JBQ, with lower potential for
JPS/IST over similar period. Increased showers are expected today,
especially affecting northwestern and interior PR and San Juan
metro, likely higher vertical extent. Winds generally out of the
east at 10 to 15 knots, with stronger gusts, especially VC SHRA,
decreasing after sunset.

&&

.MARINE...

Winds up to around 15 knots will create seas up to 5 feet across
most of the offshore waters and local passages and between 2 to 4
feet elsewhere.

.SURF ZONE CONDITIONS...Beachgoers, there is a high risk of rip
currents for most of the beaches from Aguadilla to Dorado, and
also for Cramer park beach and the easternmost beaches of St Croix.
There is a moderate risk of rip currents for most of the remaining
beaches except for the protected beaches in the south and west coast
of Puerto Rico.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 85 73 87 74 / 50 40 30 30
STT 83 74 84 74 / 50 30 20 30

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
526 AM AST Tue Mar 1 2022

.SYNOPSIS...
A surface ridge will continue to sink southwards across the northeast
Caribbean the next few days as a weak low level trough exits the
region resulting in a prevailing southeast wind flow. A slightly
drier airmass will filter in today through Wednesday along with
slightly warmer temperatures especially along the north coastal
areas. Afternoon showers will still however be possible mainly
across parts of the central and west sections of Puerto Rico and
mainly downwind of the U.S. Virgin Islands. Increasing moisture
is again expected by Thursday onwards as well as instability aloft
as the upper lever ridge gradually erodes ad the easterly winds
increase.

&&

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

Moisture is decreasing across the region, as a drier airmass moves
into the area from the east. Data from GOES-16 shows that an airmass
with precipitable water values estimated to be around 1.2 to 1.3
inches has made its way over the eastern half of the CWA. The ridge
is reasserting itself at the mid-levels, increasing stability over
the region. As such, decreasing shower activity is anticipated. Even
so, there is sufficient moisture to sustain some typical shower
activity, and lingering moisture in the west will combine with
daytime heating and local effects to lead to some showers in
northwestern and interior portions of Puerto Rico. The San Juan
metro may also see some showers this afternoon, as well, though
activity will be inhibited, and is dependent on patchy moisture that
will move through the area from time to time. Further dry air is
expected to affect the region tomorrow, as well. As such, another
decrease in shower activity is likely, both in passing showers and
afternoon convection.

On Thursday, the ridge aloft will begin to be eroded, under the
influence of a deep-layer polar trough located north of the region,
associated with a rapidly deepening surface low over the central
Atlantic. This will gradually decrease stability over the area,
likely moreso later in the day. Additionally, a disturbance is
expected to make its way into the region from the east, bringing
increased moisture, and additionally modestly increasing instability
over the area. Therefore, an increase in showers is anticipated. The
increase will likely be more modest through the morning, and then be
more noticeable in the afternoon and onwards. An increased threat
for urban and small stream flooding is likely for Thursday.

.LONG TERM...Friday though Wednesday...

The aforementioned mid- to upper-level ridge will continue to erode
on Friday, as the polar trough crosses the west and southwest Atlantic.
This in turn will continue to destabilize the upper levels and support
better chance for convective development in and around the islands,
especially during the early morning and afternoon hours. Additionally
low level moisture convergence is expected to increase as an induced
surface trough crosses the region. This pattern will favor increase
instability aloft and moisture convergence with better potential
for convective development into the the early part of the upcoming
weekend. As a result of the expected conditions and the increase
in enhanced shower activity, the potential for urban and small stream
flooding as well as ponding of waters on roads and in poor drainage
areas will be moderate to high for much of the weekend but only in
isolated areas where periods of heavy rains will be possible.

By late Sunday and into early next week, patchy moisture is forecast
to linger across the region, as the upper trough is still expected
to weaken while lifting east northeast of the region and the surface
Atlantic ridge builds builds north of the area once again. This will
however help to transport sufficient moisture over the area and
therefore early morning and afternoon convection will be likely
but with lesser coverage. Recent model guidance continued to suggest
sufficient instability aloft over the weekend with cooler 500 hPa
temperatures Saturday into Sunday. Consequently this would support
convective development with slight potential for isolated afternoon
thunderstorms mainly over the west interior sections of Puerto Rico.
For the rest of the period, a gradual erosion of low level moisture
is expected as the upper ridge reestablishes and the prevailing east
to northeast winds increase along with the trade wind cap inversion.
This will result in a more seasonal weather pattern with generally fair
and more typical weather conditions expected for much of the islands
the remainder of the period.

&&

.AVIATION...
VFR conditions are expected to prevail across all terminals for the
next 24 hours. Brief MVFR possible, associated with afternoon
showers, for TJBQ/TJSJ between 01/17Z and 01/23Z. Winds pick up
after sunrise out of the east/east-southeast at 12 to 16 knots, with
sea breeze variations. Stronger gusts possible near showers. Winds
diminish after sunset, becoming generally light.

&&

.MARINE...
Marine conditions will continue to improve at least through Wednesday,
and mariners can expect seas up to 5 feet, across the offshore waters,
and at 4 feet or less elsewhere. Winds will continue from the southeast
at 15 knots or less, becoming more easterly and gradually increasing
by Thursday and into the weekend. A northeasterly swell is also forecast
to arrive by Thursday. This will favoring choppy to hazardous seas into
the upcoming weekend, when precautionary statements and small craft
advisories will be possible. Please refer to the latest Coastal
Waters Forecast (CWFSJU) and Marine Weather Message (MWWSJU)
issued by WFO San Juan PR.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 86 74 86 75 / 30 20 20 20
STT 84 75 84 74 / 20 40 30 40

&&

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
517 AM AST Wed Mar 2 2022

.SYNOPSIS...
Mid to upper level ridge will hold across the region but will erode
Thursday through Friday as a broad polar trough moves eastward across
the west Atlantic and north of the region. Surface high pressure will
hold across the central and east Atlantic while a weakening stationary
front will linger just northwest of the region. This will induce a
weak low level trough and fairly light east southeast winds until
Thursday, then increase and become more easterly by Friday. An overall
seasonal weather pattern dominated by trade wind showers and brief
localized afternoon showers will continue today, however favorable
conditions aloft will increase the chance for shower development from
Thursday and possibly into the weekend, with the potential for urban
and small stream flooding.

&&

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

Patchy moisture is making its way into the region from the east. The
mid- to upper-level ridge is being gradually eroded, under the dual
influences of a weak low to the east/southeast and an approaching
deep-layer trough from the north. This will lead to a modest
increase in instability over the area, though there will likely
still be sufficient stability to inhibit activity somewhat over the
area. That being said, scattered showers have been seen across the
local waters, especially in the east, some of which have made their
way onshore from time to time in windward portions of the islands.
In northeastern Puerto Rico as well as St. Croix, periods of
moderate to heavy rainfall were seen during the morning hours, with
rainfall totals of up to about 0.8 inches locally in Luquillo,
Fajardo, and Rio Grande. 0.17 inches of rain were reported at
Rohlsen Airport in St. Croix. This passing shower pattern will
continue this morning.

In the afternoon, a dry slot will make its way across eastern
portions of the region, decreasing shower activity there. In the
west, afternoon convection is likely, associated with the moisture
that will persist there through the afternoon combined with local
effects and daytime heating. Some shear is expected aloft, and winds
will be shifting and varying for parts of the mid-levels. This
will inhibit significant shower development. Additionally, the
wind shift is expected to bring more northeasterly winds to the
mid-levels, around 800 to 600 hPa today, and therefore showers
have a good chance of drifting from western/northwestern and
interior Puerto Rico into southwestern Puerto Rico later in the
afternoon, especially those with the strongest/deepest updrafts.
Because of this, much of the western quarter to third of the
island have a pretty good chance for seeing a shower or two.

A disturbance makes its way into the region tomorrow. An induced
surface trough will carry moisture into the area from the east, as
it interacts with a frontal boundary stalled out well to the north.
This will stretch the feature out northward as moisture is pulled
into the Atlantic as it crosses the islands. The trend towards
increasing instability will also continue tomorrow and Friday.
Precipitable water values will be on the order of 1.6 to 1.8 inches,
which is above seasonal normals, supporting enhanced shower
activity, especially combined with the increased instability. As
such, active weather is expected for the end of the work week. The
typical shower pattern will be maintained, with passing showers in
the east and afternoon convection in the west, with streamer
development also affecting the east. Locally heavy rainfall is
likely, and urban and small stream flooding will be a concern,
especially for western/northwestern and interior portions of Puerto
Rico and the San Juan metro area.

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

The mid- to upper-level ridge will be replaced by a broad polar
trough which will sweep across the region Saturday through Sunday
while destabilizing the upper levels. This will continue to favor
a moderate to high potential for enhanced convective development
in and around the islands, especially during the early morning and
afternoon hours. Additionally model guidance continued to suggest low
level moisture convergence to increase as the induced surface trough
crosses the region. This overall pattern will maintain instability
aloft and good low level moisture convergence with the best potential
for convective development through Saturday and at least into early
Sunday. As a result of the expected conditions, the potential for urban
and small stream flooding as well as ponding of waters on roads and
in poor drainage areas will continue for much of the weekend but mainly
in isolated areas where periods of heavy rains will be possible.

By late Sunday and into early next week, patchy moisture is forecast
to linger across the region, as the upper trough is expected to lift
east northeast of the region while weakening and the surface Atlantic
ridge builds north of the area once again. This pattern will however
help to transport sufficient moisture over the area and therefore early
morning and afternoon showers will be likely, but with lesser coverage.
Recent model guidance continued to suggest sufficient instability aloft
over the weekend with cooler 500 hPa temperatures Saturday through
Sunday. Consequently this would support convective development with
still a potential for isolated afternoon thunderstorms but mainly over
the west interior sections of Puerto Rico.

For the rest of the period, a gradual erosion of low level moisture
is expected as the upper ridge reestablishes and the prevailing east
to northeast winds increase along with the trade wind cap inversion.
This will result in a more seasonal weather pattern with generally
fair and more typical weather conditions expected for much of the
islands the remainder of the period.

&&

.AVIATION...
Generally VFR conditions are expected to prevail for the next 24
hours for all aerodromes, except brief MVFR for TISX until 02/09Z
due to SHRA. Brief MVFR or worse cannot be ruled out this morning
until 02/14Z for TIST/TISX and this afternoon for TJBQ between
02/17Z and 02/23Z, though the peak in shower activity will likely
remain S/SE of the aerodrome. VCSH return after 03/03Z for
TIST/TISX. Winds pick up after sunrise out of the E to ESE at 10
to 15 knots, with sea breeze variations.

&&

.MARINE...
Seas will be up to 5 feet and winds up to 15 knots today through
Thursday. However, winds and seas will increase by Friday into the
weekend due to the tightening of the local high pressure gradient
and a small northeasterly swell. This will generate choppy to hazardous
seas through the upcoming weekend. There is a high risk of rip currents
for some of the north facing beaches of Puerto Rico, all beaches
of Culebra and some north facing beaches of St Thomas, while most
of the remaining beaches will have a moderate risk of rip currents.
Risk current risks are expected remain moderate to high for most
beaches Friday and through the weekend. Stay tuned for additional
info and updates issued by the NWS WFO San Juan PR.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 86 74 85 73 / 30 40 40 40
STT 85 74 84 74 / 40 50 50 50

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
454 AM AST Thu Mar 3 2022

.SYNOPSIS....A deepening trough over the western Atlantic will
promote deeper moisture and instability to envelop the region
through the rest of the workweek into early next week. This will
maintain the potential for localized urban and small stream
flooding. Wind-driven seas and a small northerly swell will
promote choppy to hazardous seas by the end of the workweek into
the upcoming weekend.


&&

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

A weak low pressure at 700 and 500 mb will move south of the area as
a low level trough moves into the area from the east with a band of
moisture. At 03/08Z, precipitable water values were around 1.1
inches over central Puerto Rico and over 1.6 inches in the band of
moisture over the Leeward Islands. This band of moisture is expected
to cross the U.S. Virgin Islands around 03/15Z and Puerto Rico
between 26/18-24Z. Some of these showers are expected to be heavy
enough to produce local urban and small stream flooding in PR, much
as yesterday. Moisture will diminish somewhat on Friday, but heavy
showers are still likely in western Puerto Rico in the afternoon.
Then on Saturday, the approach of an upper level trough and some
better moisture will bring another round of showers and possibly
some thunderstorms.

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

Model guidance continues to suggest, for the most part, an
unseasonably wet and unstable weather pattern for the first half of
the long-term period. GFS and ECMWF are consistent on the effects of
a deepening upper-level long wave trough across the northeast
Caribbean basin. This will maintain an unstable weather pattern
across the area as cold air advection maintains 500 mb temperatures
at below-normal levels through at least Tuesday of next week with
values between -10 to -9 degrees Celsius. Low-level lapse rates will
remain steep across this area with mid-level lapse rates starting
steep on Sunday and gradually decrease through mid-week of next
week. Above-normal moisture within the atmospheric column from
remnants of a frontal boundary is expected to persist through early
next week with relative humidities within the 700-500 mb layer
two standard deviations above normal for this time of year. These
weather conditions will be conducive for the continuation of
organized convection across the forecast area on Sunday, elevating
the potential for heavy rainfall, widespread activity is possible,
with a gradual decrease in coverage as the week progresses.

Some uncertainty, however, exists regarding the positioning of the
most active area from the aforementioned trough putting forecast
confidence between low to moderate. Latest solutions of both global
models center the activity across the northwest/north of the
forecast area, over the Atlantic waters, with convective activity
spreading through the northern CWA, enhanced by surface heating and
orographic lifting mostly over interior and western Puerto Rico by
Sunday afternoon. Monday and Tuesday still shows the potential for
isolated thunderstorms but higher probability for shallow
convection. Although coverage of deep convection decreases for both
of these days, there will still be enough available moisture
supporting the potential for localized heavy rainfall over land
areas, especially over windward coastal areas of the islands during
overnight and morning hours, and later moving over interior and
western sections of Puerto Rico, as well as downwind of the
eastern local islands. Therefore, expect a moderate to briefly
high flooding threat with the potential of urban and small stream
flooding with Sunday the wettest day of the long-term period.
Special attention should be given to those areas with saturated
soils as rains from previous days could increase vulnerability in
those parts.

On Wednesday, a gradual, slight drying trend will begin. The mid- to
upper-level trough will slowly pull away from the area, increasing
somewhat the stability aloft. As such, decreasing shower activity is
expected, a trend that will continue through the end of the week.
Moisture is likely to remain at seasonal normal levels through the
end of the forecast period promoting passing showers during the
morning and overnight hours, affecting windward parts of the
local islands, and afternoon showers due to local effects, diurnal
heating, and sea breeze convergence.


&&

.AVIATION...VFR conds will prevail except for MVFR in passing SHRA
in the Leeward Islands and the USVI. Aft 03/16Z, areas of +SHRA will
dvlp to bring MVFR/IFR conds to wrn and interior PR with mtn
obscurations. SHRA will diminish aft 03/23Z, but sct SHRA will cont
ovr ern PR. Sfc winds E 10-15 kts with hir gusts in sea breezes.
Winds bcmg land breezes at less than 10 kts aft 04/00Z.


&&

.MARINE...Winds of 10 to 20 knots will prevail throughout the
workweek. Increasing winds and a small northerly swell will
promote choppy to hazardous seas by the end of the workweek into
the weekend, conditions that may require Small Craft Advisories.
Due to breaking waves of 6 to 9 feet, causing life-threatening rip
currents, a high risk remains in effect for beaches of
northwestern St Thomas and St. John, eastern St. Croix, northwestern
to northeastern Puerto Rico, and most beaches of Culebra.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 86 72 86 74 / 50 60 50 70
STT 83 73 83 73 / 50 50 40 50

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
508 AM AST Fri Mar 4 2022

SYNOPSIS...Unsettled weather conditions are expected by the
weekend into early next week as a deepening trough will continue
to bring moisture and instability over the region. An increasing
threat for urban and small stream flooding and in poor drainage
areas is expected for the next several days. Marine conditions
will start to deteriorate due to increasing winds and a weak
northeasterly swell, causing choppy to hazardous seas and life-
threatening conditions.


&&

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

Drier air is filtering into the area in easterly flow and a weak low
level trough is moving across Puerto Rico and will exit the area
later this morning. This has brought showers to the Atlantic and
Caribbean waters, but only a small part of Puerto Rico from Naguabo
and Humacao to Cayey received significant rainfall--up to 3 tenths
of an inch. San Juan did have one one hundredth after 2 AM AST.
Alternating patches of moist and dry air at low levels will continue
to transit across the forecast area today and over the weekend. High
pressures at the surface over the eastern and western Atlantic will
join north of the area to cause winds to increase considerably later
Sunday. Mid levels continued to be characterized by slightly lower
pressures than the surrounding areas, while an upper level trough
with cooler air is approaching Puerto Rico. It will pass north and
over the area on Sunday and will be somewhat favorable to showery
activity. Thunderstorms are possible on Sunday and into the long
term. Ordinarily the pattern would be fairly amenable to heavy
rainfall, but precipitable water will be lacking until Sunday and
will reach a minimum value of 1.3 inches Saturday morning.
Therefore, rain chances have been moderated somewhat Saturday
morning. Overnight periods however will tend to be wet in eastern
Puerto Rico during the period.

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

On Monday morning, the pressure gradient across western Atlantic
will tighten producing breezy conditions across the region while
remnants from an old frontal boundary will continue to engulf the
northeastern Caribbean basin. This will continue to provide low-
level moisture convergence across the area, with precipitable
water levels above seasonal normals - the 00Z GFS run shows levels
around 1.5 to 1.8 inches. Meanwhile, a deepening upper- level
trough will drag on providing instability aloft while
strengthening a mid-level low meandering over the forecast area,
centered across southeastern Puerto Rico at the beginning of the
long-term forecast period. Cold air advection at mid-levels will
maintain steep low to mid level lapse rates and 500 mb
temperatures at well below normal levels, between -12 to -10
degrees Celsius through at least Tuesday. The GFS and ECMWF
Galvez-Davison Index continue to indicate an increased potential
for organized convection with this weather pattern, especially
for Monday, capable of producing heavy rainfall across the CWA.
These weather conditions are expected to persist through at least
Tuesday. Forecast confidence continues to grow regarding this
weather pattern, however, placement of mid-level low and deepening
upper-level trough continues to change slightly affecting
potential impacts across the area. Therefore, please continue to
monitor our forecast as we follow the evolution of this event.
Nevertheless, expect a moist and unstable weather environment
across Puerto Rico and U.S. Virgin Islands, with the potential
for widespread convection and heavy rainfall on Monday through
Tuesday. Urban and small stream flooding can be expected in areas
with the heaviest showers.

Latest model guidance has shifted slightly on the weather pattern
for the remainder of the week. Although not as active as Monday,
models now suggest a lingering effect of the upper-level trough and
mid-level low by mid-week of next week as now it looks like it will
take longer for these features to dissipate. Moisture levels are
expected to remain at near normal to normal levels with some
instability aloft as the mid-level low wanders over the forecast
area through the end of the forecast period. This will cause shower
activity during overnight and morning hours across windward
coastal areas and the potential for scattered to numerous showers
over interior and western sections of Puerto Rico each afternoon.
With these weather conditions, isolated thunderstorms during
afternoon hours are possible, therefore it was included in the
forecast. However, uncertainty remains as changes in moisture
content and instability persist within models.


&&

.AVIATION...VFR conds will prevail except for MVFR in passing SHRA
in the Leeward Islands and the USVI. Limited SHRA to occur before
04/15Z, but aft 04/16Z, areas of +SHRA will dvlp to bring MVFR/IFR
conds to wrn and interior PR with mtn obscurations. SHRA will
diminish aft 04/23Z, but sct SHRA will cont ovr ern PR. Sfc winds E
10-15 kts with hir gusts in sea breezes. Winds bcmg land breezes at
less than 10 kts aft 05/00Z.


&&

.MARINE...Seas up to 6 feet can be expected today and tonight
with winds up to 20 knots from the east. There is a high risk of
rip currents for the beaches of northwestern to northeastern PR,
Culebra, as well as several beaches of the USVI.

Increasing winds and a weak northerly swell will promote
hazardous seas this upcoming weekend into early next week. Small
Craft Advisory was issued for the offshore Atlantic waters
starting Saturday afternoon. Additional Small Craft Advisories
will be issued as seas increase across the regional waters for the
next several days.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 84 74 83 74 / 30 60 60 80
STT 83 73 81 73 / 20 40 40 50

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
525 AM AST Sat Mar 5 2022

.SYNOPSIS...Increasing instability and an approaching upper level
trough will bring increasing showers and the possibility of
thunderstorms to the area today through Monday. This will also
bring a higher risk of rip currents. Some warming but continued
showers in the typical diurnal pattern will continue through the
rest of the period.

&&

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

Precipitable water values have increased across the area as observed
by satellite imagery as moisture advected by the easterly flow
converges ahead of a frontal boundary northwest of the forecast
area, currently over the Atlantic waters. This has caused an
increase in passing showers across the local islands during the
night hours. This activity is expected to remain mainly over the
north Atlantic waters affecting northeastern coastal areas of the
local islands during the morning hours. As the day progresses, this
surge of moisture in combination with sea breeze and surface heating
will aid in the development of afternoon showers over the interior
and western portions of Puerto Rico. An upper-level trough west of
Puerto Rico is expected to deepen today as it moves eastward while
reinforcing a mid-level low meandering over the eastern Caribbean.
This will support unstable weather conditions aloft. If this feature
coincides with afternoon convection, isolated thunderstorms could be
observed over western Puerto Rico this afternoon.

The upper-level trough and mid-level low are expected to strengthen
through the short-term period. Meanwhile the frontal boundary is
forecast to move over local Atlantic waters and slowly meander
across the region, with the bulk of moisture sinking across Puerto
Rico and U.S. Virgin Islands. Above normal moisture content and
unstable weather conditions will promote periods of prolonged
moderate to heavy showers with the potential of thunderstorm
activity leading to urban and small stream flooding across Puerto
Rico and USVI. Latest model guidance suggest the most active period
will be between Sunday evening through early Monday. A broad surface
high pressure building over the western Atlantic will tighten the
pressure gradient across the northeastern Caribbean basin promoting
20-25 mph northeast wind flow with higher gusts. This will continue
to promote an advective weather pattern through the end of the
forecast period supporting development of streamer-like showers
downwind of the local islands and mountainous regions. With these
weather conditions shower activity will be highest across
northeastern Puerto Rico and USVI, although windy conditions should
limit some rainfall accumulations across those areas.

.LONG TERM...Tuesday through Saturday.
High pressure will dominate the entire mid-latitude Atlantic ocean
by Tuesday and will be forced eastward across the Atlantic only
when a strong low pressure swings northeast across the Atlantic
coastline of the United States and Canada Thursday night and
Friday. On Friday flow at the surface will turn more east
southeasterly and with some general warming of the airmass around
us, and temperatures on the north coast will become above normal
for a few days.

High pressure at mid levels continues over the Central Atlantic and
the Gulf of Mexico until another long wave trough transits the
eastern United States over the the next weekend. Then high
pressure will build over the central Atlantic while some weakness
is found over the local area. At upper levels, the trough will be
leaning eastward over the area Tuesday, but will retreat well to
the east northeast during the next several days. A short wave
disturbance is expected to cross through the area on Friday with
some weak jet action lasting over the weekend.

Over all moisture will be moderate as mid and upper levels are
fairly dry during the period, but shallow low level moisture will
allow generally unstable low level conditions to generate showers
in the usual diurnal pattern. With night and morning showers on
the windward eastern side of Puerto Rico and somewhat stronger
convection each day during the afternoons in western Puerto Rico.
Showers will be spotty and generally few over the U.S. Virgin
Islands.

&&

.AVIATION...VFR conditions are expected across most of the
terminals through the forecast period. SHRA expected across
interior and northeastern PR through 05/22z, this may cause tempo
MVFR at TJSJ. MVFR conditions are possible tonight and through
late in the forecast period across the northern PR terminals and
TIST due to an approaching frontal boundary. Winds will peak up at
10 to 15 knots with stronger gusts after 05/12Z.

&&

.MARINE...Winds and seas will be on the rise today through Sunday
night with some areas having up to 23 knots with gusts to 30 knots
possible and seas rising to 10 feet by Late Sunday night. Small
craft advisories for seas are expected to last through at least
Wednesday for the local outer Atlantic waters. The risk of rip
currents will be high for beaches with northern exposures. The
risk and strength of these rip currents will increase through
Monday for all beaches in the area.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 83 74 83 72 / 50 80 80 80
STT 81 73 83 72 / 40 80 80 60

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
534 AM AST Sun Mar 6 2022

.SYNOPSIS...Predominately easterly surface flow and a front to the
northwest will maintain showery, cool and unstable conditions
through Tuesday. Low level moisture will persist through the end
of the week allowing shallow showers and some afternoon
thunderstorms in western Puerto Rico Wednesday through Saturday.
A high risk of rip currents will spread to most coasts today and
Monday and for northern beaches the high risk will continue
through much of the week.

&&

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

Moisture advection under an east northeast wind flow with a frontal
boundary stalled northwest of the area has promoted a cool
advective pattern through the night hours with showers affecting
mainly the U.S. Virgin Islands and the eastern third of Puerto
Rico, including Vieques and Culebra. Although instability aloft is
present, a slight decrease in moisture at the mid-levels has
significantly reduced the thunderstorm activity across the
waters. In fact, no thunderstorms were detected throughout the
night over the forecast area. This slight reduction in moisture at
the mid-levels is expected through the morning hours. As such,
thunderstorms were removed from the forecast through late this
morning, although some very brief isolated thunderstorms cannot be
ruled out over the local waters. Regardless, scattered to
numerous showers will continue to affect windward coastal areas
through the morning hours.

The frontal boundary is not expected to move much closer to the
forecast area. However, it is anticipated that its associated
moisture will interact with a strengthening mid-level low over
the northeastern Caribbean basin and a deepening upper-level
trough today while moving eastward across the forecast area. This
will promote moisture fragmentation at the mid-levels from the
southern tip of the frontal boundary and later sinking southward
today through Monday as moisture embedded in the northeasterly
trades will continue to moisten the boundary layer. This will
support above normal moisture content up to 500 mb. This, in
combination with unstable weather conditions aloft, surface
heating, and mountain effects will produce another round of fairly
active showers and thunderstorms this afternoon. Global models
have backed off slightly from widespread thunderstorm activity
due to a slight reduction in available moisture. Nevertheless,
weather conditions still look optimal for shower and thunderstorm
activity capable of producing gusty winds and periods of moderate
to heavy rain this afternoon for interior and western sections of
Puerto Rico which will cause areas of urban and small stream
flooding. Fresh to strong wind conditions will also aid in the
formation of streamers downwind of Vieques and Culebra which could
affect the eastern municipalities of Puerto Rico and also
downwind of El Yunque into the southern sections of the San Juan
metropolitan area.

This activity is expected to persist through Sunday evening and
Monday morning with the potential of shower and thunderstorm
activity over the local waters moving over windward coastal areas,
especially over the northeastern municipalities of Puerto Rico.
Urban and small stream flooding can be expected in areas with the
heaviest showers this afternoon through early Monday morning.
Lingering moisture with instability aloft should support another
active Monday afternoon across interior and western sections of
Puerto Rico but with less coverage than today.

By Monday evening through Tuesday, moisture will decrease to
seasonal normal levels. Cloud coverage and shower activity should
decrease, but enough moisture will promote passing showers over
windward coastal areas during evening and morning hours and
localized afternoon activity mainly driven by daytime heating and
local effects across western Puerto Rico.

.LONG TERM...Wednesday through Sunday...
High pressure continues across the central Atlantic through the
rest of the period to maintain 10 to 20 knot easterly surface
flow. High pressure does briefly build toward the central
tropical Atlantic to cause more east southeasterly flow over the
forecast area Friday and Saturday, but this is now showing up
weaker than in previous model runs. Nevertheless the GFS continues
to show a warming trend through Thursday and only a gradual
cooling trend afterward. Overall, the moisture pattern at low
levels remains nearly saturated and will provide ample humidity
for shower formation wherever vertical motion factors and heating
at the surface are favorable, but no significant features move
through during the period and moisture is generally less than 60
percent between 825-600 mb. This will impede vertical development
even with moderately low 500 mb temperatures through Sunday.
Moderate wind flow will also keep showers moving although some
areas could see repeated activity to the point that ponding of
water will occur--mainly in western and interior Puerto Rico.
Upper levels are marked by a ridge building into the area from the
southeast and pushing a weak jet over the forecast area Thursday
night and Friday. This passage will enhance the showers somewhat,
but this activity will tend to be modulated more by the patchy
nature of the moisture passing through Friday through Sunday.

&&

.AVIATION...Mainly VFR conds expected with VCSH over all terminals
except TJPS through 06/14Z. Brief MVFR possible for most terminals
afterwards with VCTS in and around TJPS/TJBQ through at least
06/22z. Winds picking up to around 15 to 20 knots today, remaining
out of the east, with sea breeze variations and stronger gusts.
Maximum winds WNW 30-40 kts btwn FL320-400.

&&

.MARINE...Seas at the outer buoy have begun to increase to 8 to 9
feet, but are being caused by the increasing winds to the east. A
weak spike of seas of 5 to 6 feet did make it as far south as
Rincon earlier Saturday night but they have returned to previous
levels. Seas are expected to rise with the winds and up to 10 feet
could be seen in the northern-most waters of the local Atlantic
Sunday night with 5 foot swell from the north northeast. Periods
are expected to be 8 to 10 seconds owing to the local nature of
the generation area. Seas of at least 6 feet will continue in the
local outer Atlantic waters for the rest of the week and beyond.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 83 73 83 74 / 80 80 60 50
STT 83 72 83 73 / 60 70 50 40

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
517 AM AST Mon Mar 7 2022

.SYNOPSIS...Unstable weather conditions will persist today. The
upper level trough is forecast to continue to linger just to our
northeast, maintaining instability aloft. Rainfall accumulations
are expected today as showers develop across the day. Hazardous
and life-threatening marine conditions will continue across the
local waters. High risk of rip currents are in effect for most of
the local waters.


&&

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

Breezy conditions and passing showers prevailed across the region
through the overnight hours. Estimated rainfall accumulations were
between 0.25-0.50 inches across southeastern Puerto Rico, Vieques
and St. Croix. Gusty winds between 25-34 mph were observed with the
showers across the U.S. Virgin Islands and east/northeast coastal
sections of Puerto Rico. Showers moved further inland across
portions of the interior of PR due to the stronger than normal
winds. Minimum temperatures were from the low 60s across the higher
elevations to the low 70s across coastal areas.

The upper level trough is forecast to continue to linger just to our
northeast through the short term period. A few perturbations
rounding the base of trough axis should maintain enough instability
and colder than normal 500 mb temperatures through at least Tuesday.
However, the overall moisture content is expected to decrease later
this evening through tomorrow, with the entrance of a drier air mass
between 700-600 mb. Having said this, there is still sufficient
moisture content and instability today to enhance diurnal convection
across mainland PR, particularly across the west/southwest sections.
Elsewhere, streamer type of showers activity is expected due to the
brisk ENE winds. A cool advective weather pattern should prevail
during the night, and showers will favor the windward areas. A
drying trend is expected on Tuesday, but showers will still develop
over the same areas, with lesser rainfall amounts than today.
Moisture increases once again on Wednesday, but instability
decreases as the upper level trough pulls further east and away of
the region. At the surface, the strong surface high across the
western Atlantic will continue to promote fresh to locally strong
trade winds through at least today, and the northeasterly trades
will shift more from the east to southeast by Wednesday.

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

A dominant surface high pressure over the Atlantic waters is the
main feature, at least for the first half of the long period. The
tightening of the pressure gradient leads to the acceleration of
the trade winds over the Caribbean Basin. In the low levels of the
atmosphere moisture remains nearly saturated and will provide
ample humidity for shower activity across the islands. This
pattern will enhance the potential for morning showers over
portions of eastern Puerto Rico from time to time. Daytime heating
and local effects will help for the development of afternoon
convection over the central interior and western Puerto Rico.

The latest GFS model guidance is forecasting an upper level ridge
moving into the local area by the end of the workweek. Patches of
moisture pulled from the Caribbean will place over the islands,
enhancing unstable conditions aloft and shower formation. This
pattern will linger through the end of the long period. Expect
warmer temperatures and rainy afternoons.


&&

.AVIATION...Brief periods of MVFR conds will remain possible at TISX
and TJSJ thru early this morning. Then, mainly VFR conditions
expected across all terminals. However, SHRA/TSRA may develop over
the western interior of PR, causing MVFR cigs across the western
terminals thru at least 07/22z. Winds will continue from the ENE,
increasing btw 14 and 18 knots with stronger gusts aft 07/14z.

&&

.MARINE...Hazardous marine conditions will continue across the
local waters. Wind driven waves and a small northeasterly swell
will produce seas up to 10 feet. A Small Craft Advisory is in
effect for most of the local waters of Puerto Rico and the U.S.
Virgin Islands. High risk of rip currents are in effect for all
the beaches of Puerto Rico, except the south central and
southwestern Puerto Rico, and also includes Culebra, Vieques, and
the U.S. Virgin Islands.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 82 73 84 73 / 60 50 50 50
STT 84 72 84 74 / 50 50 50 50

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
453 AM AST Tue Mar 8 2022

.SYNOPSIS...More stable weather conditions are expected for today
and the next several days. Trade wind showers are expected in the
morning hours for eastern Puerto Rico and the USVI, and then
afternoon convection over the central interior and western
sections of Puerto Rico. Hazardous marine conditions continue
across the local waters. Small Craft Advisories are in effect for
mos of the local waters and passages.

&&

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

Trade wind showers moved at times across portions of the islands
during the overnight hours. Rainfall accumulations were in general
between a tenth and three tenths of an inch. Gusty winds up to 30
mph were reported across the northeastern coast of PR. Minimum
temperatures ranged from the low 60s across the mountains to the low
70s across the lower elevations. Moderate to fresh northeasterly
trades will continue to bring showers across the USVI and northeast
sections of PR during the morning hours.

Colder than normal 500 mb temperatures will continue today. However,
a warming trend is expected to start this afternoon as the upper
level trough to our northeast moves further east and away of the
region. Therefore, more stable conditions aloft are expected through
the rest of the short term period. In terms of moisture content, the
precipitable water content is expected to peak today and on Thursday
near 1.40 inches, and around 1.60 inches on Wednesday. This influx
of higher moisture content is due to an induced surface trough, and
the areal coverage and intensity of showers are expected to increase
once again from early Wednesday morning through the evening hours.

Northeasterly steering winds today will favor the development of
diurnally induced showers over the southwestern sections of PR, and
from streamers with lesser rainfall amounts over eastern PR. Winds
will gradually turn more easterly on Wednesday, and southeasterly by
Thursday as the surface high relocates over the central Atlantic.
Therefore, a northward shift in afternoon convection can be expected
each day.

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

In the low levels, a surface ridge is expected to take place north
of the local area, bringing easterly trade winds that will persist
through most of the period. Strong trades will prevail generating
morning showers over eastern Puerto Rico and the U.S. Virgin
Islands. Daytime heating and local effects will help for the
development of afternoon convection over the central interior and
western Puerto Rico.

The GFS latest model guidance suggest a seasonal pattern, but
much drier weather conditions. A drier air mass pattern is
expected to prevail across the islands through the end of the long
term. However, patches of moisture pulled from the Caribbean will
place over the islands, enhancing unstable conditions aloft and
shower formation. Expect warmer temperatures and rainy afternoons.

&&

.AVIATION...Mainly VFR conditions are expected to prevail across
all terminals during the next 24 hours. However, trade winds
showers could move at times across TJSJ/TJBQ and the USVI
terminals through the period. This may cause brief MVFR cigs. ENE
winds will continue at 12-17 kts with higher gusts and sea breeze
variations aft 14z.

&&

.MARINE...Hazardous marine conditions continue across the local
waters. Wind-driven seas with the combination of a weak northeasterly
swell will generate seas up to 10 feet with higher breaking
waves. Small Craft Advisories continue in effect for most of the
local waters and passage. For beachgoers, a high risk of rip
currents remains in effect for most of the beaches in the local
islands.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 83 73 84 74 / 50 50 50 60
STT 84 73 84 74 / 40 50 50 50

&&

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
357 AM AST Wed Mar 9 2022

.SYNOPSIS...Stable weather conditions will prevail for the next
several days. A broad surface high pressure over the central
Atlantic will continue to promote breezy easterly winds
today. Trade wind showers are expected in the morning hours for
eastern Puerto Rico and the USVI, and then afternoon convection
over the central interior and western sections of Puerto Rico.
Hazardous marine conditions continue across the local waters,
including Small Craft Advisories in effect for most of the local
waters and passages.

&&

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

Showers embedded in the brisk easterly trades moved at times across
the U.S. Virgin Islands and much of the eastern and northern half of
Puerto Rico during the overnight hours. Rainfall accumulations were
from a few hundredths to half an inch. Wind gusts between 20-30 mph
were reported with the showers across coastal areas. Minimum
temperatures ranged from the low 60s across the higher mountains
valleys to the high 60s and low 70s across lower elevations.

A broad surface high pressure anchored over the central Atlantic
will continue to promote breezy easterly winds today, with forecast
soundings indicating sfc-3km winds at 20 kt. Winds are expected to
turn more ESE on Thu-Fri as the surface high shifts slightly
eastward. At the mid and upper levels, a weak low is forecast to
meander just south of Hispaniola, while a ridge builds across the
eastern Caribbean. In response, the 500 MB temperatures are expected
to remain near -9 Celsius through at least Thursday. This should
enhance diurnal convection and isolated thunderstorms are possible
over western PR each afternoon. Showers embedded in the trade winds
will continue to stream from the east during the nighttime. A drier
air mass is expected to move over the islands during the day on
Friday, but locally induced afternoon showers are still expected to
develop over western PR and downwind from el Yunque.

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

A surface high pressure, continue to be the dominant feature in the
Atlantic. The forecast has not change much since the last
discussion, and still showing the placement of a ridge over the
local region by Friday into Saturday. Tight gradients in the
Atlantic basin will persist with easterly trades up to 25 kts across
the local islands. A drier air mass is expected to entrain, with
strong trades that are favorable for the development of morning
showers across the U.S. Virgin Islands, and eastern sectors of
Puerto Rico from time to time. Warmer temperatures are expected as
this dry weather pattern will prevail throughout the long term
period. However, patches of moisture pulled from the Caribbean will
place over the islands, enhancing unstable conditions aloft and
shower formation over western Puerto Rico in the afternoon hours.

&&

.AVIATION...Mainly VFR conditions are expected to prevail across all
terminals during the next 24 hours. However, passing showers could
move at times across TJSJ and the USVI terminals through 09/16z.
Also, SHRA/TSRA is expected to develop over west PR from 09/16z-23z,
this may cause tempo MVFR conds at TJBQ. Winds are expected to
increase from the east at 12-18 kts with higher gusts and sea breeze
variations aft 09/14z.

&&

.MARINE...Hazardous marine conditions will persist through the end of the
week. A combination of wind driven seas and a northeasterly swell
will maintain rough and hazardous seas for the next several days.
Small Craft Advisories remains in effect for most of the local
waters and passage. For beachgoers, high risk of rip currents
remains in effect for most of the beaches in the local islands.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 83 73 84 73 / 50 60 40 30
STT 84 74 83 74 / 50 50 40 40

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
509 AM AST Thu Mar 10 2022

.SYNOPSIS...Variable weather conditions today across the local
islands. Morning showers across the eastern sections of Puerto
Rico and the U.S. Virgin Islands, followed by afternoon convection
over the central interior and western Puerto Rico. A drier air
mass is expected on Friday, and should promote fair weather
conditions across all the islands in general. Marine conditions
continue hazardous across the local waters.

&&

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

Trade wind showers once again prevailed through the overnight hours
across portions of the islands, with rainfall accumulations ranging
from a few hundredths to a quarter of an inch. Breezy conditions
persisted across the regional waters and coastal areas. Minimum
temperatures ranged from the low 60s across the mid and high
elevations to the low 70s across the lower elevations.

No significant change from previous discussions, best days of
moisture content across the region are today and on Saturday. PWAT
values are forecast to remain just above near normal values today
(~1.50 inches) and above normal (~1.75) inches on Saturday as the
pressure gradient relaxes and winds turn more from the southeast. A
drier air mass on Friday should promote fair weather conditions
across all the islands in general. However, diurnally induced
afternoon showers over western PR are still expected to develop on
Friday. At the upper levels, the proximity of a weak upper level
trough to our west will continue to promote marginally unstable
conditions and the 500 MB temperatures are still expected to be cold
enough to aid in the development of iso thunderstorms over western
PR this afternoon. Urban and small stream flooding is possible with
this activity. A northward shift in afternoon convection is expected
on Saturday, due to the southeasterly wind component.

.LONG TERM...Sunday through Thursday

The long term forecast have continue on track. Surface high pressure
in the Atlantic is expected to prevail as the dominant feature.
Tight gradients in the Atlantic basin will persist with easterly
trades across the local islands. A drier air mass is expected to
entrain, with strong trades that are favorable for the development
of morning showers across the U.S. Virgin Islands, and eastern
sectors of Puerto Rico from time to time. Warmer temperatures are
expected as this dry weather pattern will prevail throughout the
long term period. Patches of moisture pulled from the Caribbean
will place over the islands, enhancing unstable conditions aloft
and shower formation over western Puerto Rico in the afternoon
hours. This pattern will persist throughout the long term period.


&&

.AVIATION...Mainly VFR conditions are expected to prevail across all
terminals during the next 24 hours. However, SHRA/TSRA is expected
to develop over western PR from 10/16z-23z, this may cause tempo
MVFR conds at TJBQ. Winds are expected to increase from the east to
southeast at 12-18 kts with higher gusts and sea breeze variations
aft 10/14z.

&&

.MARINE...Hazardous seas conditions continues across the local
waters. Wind-waves and a small northeasterly swell will produce
seas between 5 to 7 feet. A Small Craft Advisory is in effect for
most of the local waters of Puerto Rico and the U.S. Virgin
Islands. High risk of rip currents are in effect for all the
beaches of Puerto Rico, except the south central and southwestern
Puerto Rico, and also includes Culebra, Vieques, and the U.S.
Virgin Islands.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 85 73 85 73 / 40 30 30 30
STT 84 73 84 74 / 40 40 50 50

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
405 AM AST Fri Mar 11 2022

.SYNOPSIS...A mass of dry air will limit moisture content across
the islands today. Overall, fair weather conditions are expected
over Puerto Rico and the U.S. Virgin Islands. However, early
morning trade wind showers, followed by afternoon convection in
the west and central interior are expected. Marine conditions
continue hazardous across the local waters.

&&

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

Breezy conditions and a drier air mass persisted across the region
through the overnight hours. A small area of low-level clouds with
light trade wind showers were moving from the Anegada Passage into
portions of the U.S. Virgin Islands by 11/06z. This should reach the
eastern areas of Puerto Rico before daybreak, leaving minor rainfall
amounts. Minimum temperatures were from the low 60s across the
higher elevations to the low and mid 70s across coastal areas. Winds
were from the east around 10 mph with higher gusts across coastal
areas.

Building upper level ridge across the eastern Caribbean will promote
more stable conditions and the entrance of a drier air mass should
limit moisture content across the islands today. Therefore, mostly
fair weather conditions are expected to prevail across the USVI and
PR. Having said that, the proximity of an upper level trough
northwest of the region and diurnal effects should lead to the
development of shallow afternoon convection; mainly over portions of
western PR. For Saturday, winds turn more southeasterly as the
pressure gradient relaxes somewhat under pressure from a polar
trough and associated surface front moving across the western
Atlantic. In response, winds will turn more from the ESE and
moisture content will increase across the region. Therefore, shower
coverage and intensity will increase in diurnal convection across
mainland PR. Urban and small stream flooding is expected with this
activity. On Sunday, another drier air mass is forecast to filter
from the east, but moisture content should remain near normal. Winds
will also turn more from the ENE. Therefore, shallow moisture
advection will favor trade wind showers across portions of the USVI
and northeastern PR during the night/early morning hours, followed
by diurnally induced afternoon showers over southwestern PR.

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

The forecast continue on track. A broad high pressure in the
Atlantic will continue to dominate the area for much of the long
term period. Drier air mass will filter into the local area, with
trades winds that are favorable for the development of morning
showers across the U.S. Virgin Islands, and eastern sectors of
Puerto Rico from time to time. Warmer temperatures are expected as
this dry weather pattern will prevail throughout the work-week.
Nonetheless, the atmosphere is conductive for mid-afternoon
convection and will feed the development of shower activity and
isolated thunderstorms across the interior, western and northwestern
Puerto Rico. Streamers are also expected to form over El Yunque are
and moving over the metropolitan area of San Juan. Overall, fair
weather conditions likely to prevail.


&&

.AVIATION...Mainly VFR conditions are expected to prevail across all
terminals during the next 24 hours. However, SHRA over western PR
may briefly cause tempo MVFR cigs at TJBQ from 11/17z-21z. Winds are
expected to increase from the east at 15-20 kts with higher gusts
and sea breeze variations aft 11/14z.

&&

.MARINE...A weak northeasterly swell in combination with easterly
winds will promote choppy to hazardous marine conditions through the
weekend, with seas up to 7 feet across the local waters. A Small
Craft Advisory is in effect for most of the local waters of Puerto
Rico and the U.S. Virgin Islands. High risk of rip currents are in
effect for all the beaches of Puerto Rico, except the south central
and southwestern Puerto Rico, and also includes Culebra, Vieques,
and the U.S. Virgin Islands.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 85 73 83 70 / 30 50 40 40
STT 85 76 83 75 / 40 50 30 30

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
443 AM AST Sat Mar 12 2022

.SYNOPSIS...

Some unstable conditions aloft combine with enough low level
moisture will result in a active afternoon, with shower and some
isolated thunderstorms, mainly over the west and interior sections
of Puerto Rico. However, not significant rainfall accumulations
are expected with the activity, just the common ponding of water
in roadways and some poor drainage areas. A more seasonal pattern
will prevail for the long term with the typical afternoon
convection each day. Marine conditions will remain choppy with
winds up to 20 knots and seas up to 7 feet.

&&

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

A surface disturbance will increase moisture, clouds, and rain
activity today. Therefore, expect showery weather conditions today.
GOES-E derived TPW imagery indicated values ranging between 1.55 and
1.75 inches or even higher, above-normal amounts for this time of
the year (March). Low-level wind convergence and local topography
will enhance shower activity through the morning hours across
Eastern Puerto Rico, and the U.S. Virgin Islands as this air mass
streams westward. Also, expect breezy trade winds, which will push
further inland rain activity reaching western PR by mid-morning. In
addition, a jet aloft will enhance vertical development, and
combined with local effects, sea breeze variations, and diurnal
heating could promote the formation of one or two thunderstorms,
especially during the afternoon or early evening hours. Periods of
moderate to heavy rains could result in ponding of water in roads
and poorly drained areas and with the most persistent activity even
urban and small stream flooding.

A typical seasonal pattern will prevail late tonight into Monday
with trade winds between 10 and 20 mph. This pattern favors
overnight/early morning showers moving over the windward areas in
PR/USVI, followed by afternoon convection across PR`s interior and
western sections and downwind from the Virgin Islands. A mid to
upper-level ridge and a somewhat drier air mass will limit rain
activity. Overnight lows will drop into the upper 60s to mid-70s
across lower elevations, while daytime highs will peak into the mid
to upper 80s (mainly across the southwest and south coast).

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

A more stable pattern is forecast for the long term period. A
building surface pressure will be the dominant feature for the
entire period at the surface. As this ridge establishes over the
central Atlantic and elongates over the rest of the area will
tighten the pressure gradient, resulting in brisk easterly winds.
Embedded in these trade winds, patches of shallow moisture with
precipitable water below the climatological normals will move into
the forecast area for most of the first part of the period. On
Tuesday, shower activity is likely due to the presence of low
level moisture over the area. After that, weather conditions are
forecast to improve from Wednesday onwards as a drier air mass
moves in. These surface conditions, in combination with a mid-
level ridge, will limit the development of heavy showers. However,
expect the typical afternoon activity each day mainly due to the
local effects and some shallow patches of moisture filtering into
the area.

So far, according to the model guidances, the best chances for
a more showery pattern starts on late Friday into Saturday when a
patch of moisture with precipitable waters values above normals
reach the islands. Consequently, the forecast includes afternoon
convection on Friday into Saturday and some passing showers in the
morning and evening hours. Daytime temperatures will reach the
upper 80s, mainly over the southern coastal plains of Puerto Rico.
The rest of the coastal areas, including the U.S. Virgin Islands,
will observe a maximum between the low and mid 80s.


&&

.AVIATION...
VFR conds will prevail today. However, SHRA/-SHRA
will move at times, bringing SCT-BKN conds btwn FL020-FL050. Also,
some +SHRA could create very brief MVFR conds. SHRA will spread
across the interior and W-PR btwn 12/15-23z. Weather conds will
improve after 12/23z. Winds will continue from the E/ESE at 10 knots
or less, increasing at 15-20 kt with gusts up to 30 kts and sea
breeze variations after 12/13z.

&&

.MARINE...
Moderate to locally fresh winds and a diminished
northerly swell will continue to result in some hazardous and
marine conditions, at least for the rest of the weekend. As a
result, mariners should expect seas up to 7 feet across the
offshore Atlantic and Caribbean waters and the Anegada Passage.
For this reason, small craft advisories are in effect. For the
beachgoers, hazardous coastal conditions will prevail across all
the north, east, and southeastern exposed beaches of Puerto Rico,
including Culebra, Vieques, and the eastern tip of St. Croix.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 84 72 85 75 / 70 30 30 40
STT 84 75 84 74 / 60 30 30 40

&&

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
447 AM AST Sun Mar 13 2022

.SYNOPSIS...
A more seasonal pattern will prevail for the rest of the weekend
and early next week. A few pockets of moisture and the local and
diurnal effects will enhance the afternoon convection, but no
significant rainfall accumulations are expected. Hazardous marine
conditions will prevail for the rest of the weekend, increasing
more early next week.

&&

.SHORT TERM...TODAY THROUGH TUESDAY...

Residents in Puerto Rico and the U.S. Virgin Islands can expect fair
weather conditions with a mixture of sunshine and clouds. However, a
few showers pushed by the easterlies could reach the islands, and
afternoon convection will develop over the western sections due to
sea breeze and local effects. Daytime high temperatures will peak
into the mid to upper 80s, mainly across the southwest and south
coast.

A strong surface high pressure across the Atlantic Ocean will
promote breezy trade winds today and tomorrow. At the same time, a
mid to upper-level ridge building over the islands will strengthen a
trade wind cap and dry air intrusion aloft. Therefore, a typical
seasonal pattern will prevail through at least Tuesday with
overnight/early morning showers moving over the windward areas in
PR/USVI, followed by limited afternoon convection across PR`s
interior and western sections and downwind from the Virgin Islands.

.LONG TERM...WEDNESDAY THROUGH SUNDAY...

A seasonal pattern is expected to prevail for the long term
period. A building ridge will establish over the forecast area at
the mid and upper levels, resulting in stable and drier conditions
aloft. Meanwhile, a building high pressure at the surface will
maintain moderate to locally fresh easterly winds over the
forecast area. As these trade winds move in, patches of shallow
moisture will reach the Islands from time to time during all the
period. So far, according to the model guidances, the first part
of the period, expect mainly clear skies with a few showers will
over the forecast area, been Thursday and Saturday the most
stables days. On late Saturday into Sunday, there are more
possibilities of shower development as patches of moisture with
precipitable water values move into the area. In general terms,
the forecast includes afternoon convection with some passing
showers in the morning and evening hours, each day. Daytime
temperatures will reach the upper 80s, mainly over the southern
coastal plains of Puerto Rico. The rest of the coastal areas,
including the U.S. Virgin Islands, will observe a maximum between
the low and mid 80s.


&&

.AVIATION...
VFR conditions will prevail today. Local terminals cannot rule
out a few quick-moving passing showers from time to time. Clouds
will develop across interior and western PR between 13/15-22z, but
we are not expecting significant cloud cover. Winds will continue
from the E at 10 knots or less, increasing at 15- 25 kt with
higher gusts of 30-35 kt or greater and sea breeze variations
after 13/13z.

&&

.MARINE...

An increase in winds will result in hazardous marine conditions
for the rest of the weekend and early next week. Given that
conditions, mariners should expect seas up to 7 feet across the
offshore Atlantic waters and the Anegada Passage. For this reason,
small craft advisories are in effect. On late Monday, the
combination of winds up to 25 knots and a weak northerly swell
invading the waters will result in seas up to 8 feet. For the
beachgoers, hazardous coastal conditions will prevail across all
the north, east, and southeastern exposed beaches of Puerto Rico,
including Culebra, Vieques, and the eastern tip of St. Croix.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 85 74 84 73 / 30 30 30 50
STT 84 74 84 74 / 20 40 40 30

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
456 AM AST Mon Mar 14 2022

.SYNOPSIS...

A stable weather pattern with breezy to windy conditions will
prevail through the next few days. However, patches of low-level
moisture embedded in the trades will enhance overnight/early
morning showers, followed by afternoon convective across the
western and interior sections. Marine and coastal conditions will
continue hazardous during the first half of the week.

&&

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

A slightly drier pattern will prevail for most of the short term
period. At the surface, a building high pressure will result in
breezy easterly winds. This wind pattern will carry patches of
shallow moisture over the forecast area, increasing the potential
for showers mainly in the afternoon hours at least today into
Tuesday. Meanwhile, a mid-level ridge will establish over the
forecast area, generating drier and stable conditions aloft.

Today, expect clear skies with limited shower activity in the
morning hours; then, by the afternoon hours, the local effects
with the available moisture will promote rainfall activity over
the western and interior sections of Puerto Rico. Rainy conditions
will prevail late tonight into Tuesday with the arrival of a surge
of moisture (near climatological normals). This showers will move
fast due to the breezy trade winds and we are not expecting
significant rainfall accumulations. A dry slot will filter into
the region by Tuesday afternoon, creating benign weather
conditions. The U. S. Virgin Islands can expect the same weather
pattern with a mixture of clear skies and a few showers, mainly by
early Tuesday. So far, Today, according to model guidances,
Wednesday looks like the driest day for the short term period.

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

The seasonal weather pattern will prevail Thursday through
Sunday, with the typical patches of moisture reaching the islands
pushed by the trade winds. The seasonal weather pattern consists
of overnight/early morning showers across the local waters and
windward sections of Puerto Rico and the Virgin Islands, followed
by afternoon convection across the interior and western Puerto
Rico and downwind from the Virgin Isles.

Surface high pressure across the Atlantic Ocean will tighten the
local pressure gradient at the surface, resulting in breezy to
locally windy conditions through at least Friday. A mid to upper-
level ridge will hold over PR and the USVI through early next
week. This ridge pattern will promote dry air and subsidence
aloft, enhancing the trade wind inversion.

A polar trough will weaken the ridge aloft as it approaches the
Northeast Caribbean from the west late Monday night into Tuesday.
Meanwhile, a surface boundary exiting the Eastern Seaboard around
Sunday, and moving into the western Atlantic through early next
week, will approach the region late Monday into Tuesday.

&&

.AVIATION...

Mainly VFR conditions will prevail for all TAF sites during the
period. Winds will become between 10-18 knots with gusty winds
around 14Z to 18Z, increasing more near the afternoon showers.
VCSH is forecast for the TJSJ, TIST, TISX & TKPK around 15/03Z and
lower ceilings. Winds will decrease at 14/22Z around most sites.
No sig impacts are expected.

&&

.MARINE...

Fresh to strong easterly winds and a small northerly swell will
promote rough seas across the regional waters. Therefore, Small
Craft Advisories are in effect through at least mid-week. This
wind pattern will hold through much of the forecast period.
Therefore, mariners should actively monitor the evolution of the
marine conditions for additional updates.

Beachgoers, life-threatening rip currents are developing across
the Atlantic Coastline of Puerto Rico and the southwest and
southeast coast. The Virgin Islands, Vieques, and Culebra can also
expect a high risk of rip currents. We urge all beachgoers to
exercise caution.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 84 73 85 74 / 30 50 20 10
STT 85 73 84 74 / 20 50 20 30

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
450 AM AST Tue Mar 15 2022

.SYNOPSIS...

Breezy to windy conditions will continue to bring showers and
clouds from time to time. However, a stable weather pattern will
prevail through the week. Afternoon convection across the western
and interior sections cannot be ruled out each day. Marine and
coastal conditions will continue hazardous through the work-week.

&&

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

According to GOES-16 Imagery, a cluster of cloudiness with
precipitable water around 1.2 inches are moving into the forecast
area. As a result, cloudiness with isolated to scattered showers
will continue to move mainly over the windward sections and
coastal waters through the morning hours. Breezy winds will
persist, given to a surface high pressure across the Atlantic
Ocean. This wind flow will create fast moving rains and will not
leave significant rainfall accumulations. Conditions are forecast
to improve throughout the day, with stable atmospheric conditions
and moisture erosion from this afternoon onwards.

Tuesday and Wednesday, a ridge aloft will promote stable and
drier conditions from mid to upper levels. This mid/upper feature
will induce a trade wind cap inversion over the forecast area,
limiting vertical development and deep convection, especially in
each afternoon. A patch of shallow moisture will reach the islands
on Wednesday, increasing shower activity. Thursday seems to be
the driest day, with the arrival of a much drier air mass.

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

Therefore, the most-possible scenario consists of a mixture of
mostly clear skies (during the nighttime) or sunshine (during the
morning) and clouds with overnight/early morning showers across
the local waters and windward sections of Puerto Rico and the
Virgin Islands. Then, afternoon convection can not be ruled out
across the interior and western Puerto Rico and downwind from the
U.S. Virgin Islands each day.

Global model guidance (GFS/ECMWF) consistently indicates a stable
advective pattern for the Northeast Caribbean through at least
Sunday. This weather pattern consists of a surface high pressure
across the Atlantic Ocean promoting a tight local pressure
gradient, which will result in breezy to locally windy conditions
through possibly the weekend. Then, patches of moisture embedded
in the trades will bring clouds and showers mainly across the
windward sections from time to time. Meanwhile, a mid to upper-
level ridge will hold over PR and the USVI through early next
week, promoting dry air and subsidence aloft, reinforcing the
trade wind inversion.

Both GFS/ECMWF indicate a change in the weather pattern after
Sunday when a polar trough interacts with the ridge aloft as it
approaches the Northeast Caribbean from the west late Monday night
into Tuesday. This trough will increase instability and the
potential to observe organized convection (meaning thunderstorm
development). Meanwhile, a surface boundary is forecast to exit
the Eastern Seaboard by the end of the weekend, moving eastward
across the western Atlantic and approaching the islands by Tuesday
or Wednesday (next week). The pattern described above could
increase the potential for unsettled weather conditions.

&&

.AVIATION...

Mainly VFR conditions will prevail most of the period. However,
clusters of clouds would bring SHRA/-SHRA from time to time. This
could briefly reduce VIS, mainly over TJSJ, TIST, and TISX through
15/15Z. Winds will remain from the E at 15 knots and higher gusts
til 15/14Z; then, they will increase between 15-20 knots with sea
breeze variation and higher gusts. No sign impacts are forecast.

&&

.MARINE...

Fresh to strong easterly winds and a small northerly swell will
promote rough seas across the regional waters. Therefore, Small
Craft Advisories are in effect through much of the work-week.
This wind pattern will hold through much of the forecast period.
Therefore, mariners should continue to actively monitor the
evolution of the marine conditions for additional updates.

Beachgoers, life-threatening rip currents continues across the
majority of the Coastline of Puerto Rico and the U.S. Virgin
Islands. After mid-morning today, the building of dangerous
breaking waves will deteriorate even more coastal conditions.
Therefore, a High Surf Advisory is in effect for the Atlantic
Coastline of Puerto Rico, Culebra, St Thomas and St Croix. We
urge beachgoers to exercise caution.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 84 74 85 74 / 20 20 20 30
STT 86 73 86 73 / 20 20 10 20

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
439 AM AST Wed Mar 16 2022

.SYNOPSIS...

Breezy trade winds will continue across Puerto Rico and the US
Virgin Islands. Patches of moisture embedded in the trades will
reach the islands from time to time, resulting in fast-moving
passing showers. In general, expect stable weather conditions with
a combination of sunshine/mostly clear skies and passing
clouds/rains. Hazardous coastal and marine conditions persist in
Puerto Rico and the US Virgin Islands.

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

A wind surge will bring showers across the region throughout the
day. A ridge aloft will maintain stable weather conditions. This
mid/upper-level ridge will hold through the period, promoting dry
air and subsidence aloft, resulting in a strong trade wind cap.
This trade wind inversion will limit vertical development.

A wind surge is expected to increase cloudiness and rain activity
through sectors of eastern Puerto Rico by Thursday morning. Then,
expect limited convection developing over the interior and
southwest Puerto Rico during the afternoon. However, the breezy
conditions will limit rainfall accumulations. A surface high
pressure spreading northeastward across the Atlantic Basin will
promote a windy and advective weather pattern on Friday too.

.LONG TERM...SATURDAY THROUGH WEDNESDAY...

A stable advective pattern will persist through the weekend
across the local islands. Therefore, a combination of mostly clear
skies and clouds with the overnight/early morning showers across
the local waters and windward sections of Puerto Rico and the
Virgin Islands will remain possible each day. Afternoon convection
cannot be ruled out across the interior and western Puerto Rico
and downwind from the U.S. Virgin Islands each day. However, GFS
is propagating an air mass with below-normal moisture content
across the islands by Sunday, which could limit even more shower
activity in the morning and afternoon hours.

Early next week, meaning Monday through Wednesday, both global
model guidance (GFS/ECMWF) are eroding the ridge pattern aloft by
approaching a polar trough to the Northeast Caribbean. Although
there are some minor discrepancies between them related to the
timing, position, and intensity of this upper-level trough, both
guidances suggest a trend to observe a drop on the 200 MB Heights
after Sunday, reaching a local minimum on Tuesday and rising again
by Wednesday. The instability could increase across the region
due to this feature. Meanwhile, a cold front is forecast to exit
the Eastern Seaboard by Sunday, moving eastward across the western
Atlantic. However, the latest guidance has it off to the north of
the islands, with the remnants of an older cold front (the one
affecting CONUS on Wednesday 16th of March (today)) moving across
the islands embedded in the trades. Although it is too early to
determine the final impacts of these upper level and surface
features, Puerto Rico and the Virgin Islands islanders can expect
a somewhat climatological/seasonal pattern. This pattern consists
of the typical overnight/early morning passing showers across the
windward sections followed by afternoon convection (which
depending on the trough final position, timing, and intensity,
could aid in thunderstorm formations) across the interior and
western portions of the islands.

Something else to mention is that the surface-high pressure across
the Central and Eastern Atlantic Ocean is tightening the local
pressure gradient, which could maintain breezy to windy trade
winds next week, especially around mid-week.

&&

.AVIATION...

Mainly VFR conditions will prevail thru the period. VCSH will
affect TJSJ, TIST, and TJBQ thru 16/14Z. Winds will remain from
the E at 15 knot or less until 16/ 12Z, increasing up to 18 knots
with gusty winds and sea breeze variation. Another round of
SHRA could affect KPK/IST/ISX/JSJ between 16/22Z-17/06Z,
resulting in MVFR ceiling conditions.

&&

.MARINE...

Fresh to strong easterly winds and a small northerly swell will
promote rough and hazardous seas across the regional waters.
Therefore, Small Craft Advisories are in effect through much of
the week. This wind pattern will hold through much of the
forecast period. Therefore, mariners should continue to actively
monitor the evolution of the marine conditions for additional
updates.

Beachgoers, life-threatening rip currents continue developing
across most of the Coastline of Puerto Rico and the U.S. Virgin
Islands. In addition, dangerous breaking waves continue batting
the north-facing beaches of Puerto Rico and the northern Virgin
Islands, where a High Surf Advisory is in effect. We urge
beachgoers to exercise caution.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 84 74 84 73 / 30 40 30 40
STT 86 73 86 72 / 40 40 30 40

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
437 AM AST Thu Mar 17 2022

.SYNOPSIS...A generally stable weather pattern with breezy
conditions will prevail through the end of the workweek into the
weekend. At times, patches of low-level moisture embedded in the
trade winds will bring isolated to scattered shower activity and
support afternoon shower development, but rainfall accumulations
should be minimal. Lack of wetting rains will further dry soils
and fuels, leading to a threat of wildfires, mainly across
southern Puerto Rico. Moderate to fresh winds and a weak small
northerly swell will maintain choppy to hazardous marine and surf
zone conditions.


&&

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

Easterly winds, generally around 10 mph overnight, and up to 20 mph
during the day with occasional gusts are expected through the short
term period due to a surface high pressure that will remain near the
north central Atlantic as it slowly moves east. The mid to upper
levels are fairly stable, as a ridge of high pressure will prevail
over the local area. The available moisture will remain near to
below normal through the short term period. The precipitable water
will be below normal today, but will increase to near normal on
Friday. However, on Saturday, the precipitable water will be below
normal over the local islands, but it will be above normal over the
nearby waters. Therefore, generally brief isolated to scattered
showers are expected in the overnight and in the morning hours
across the USVI, and northern and eastern PR today and on Friday,
though perhaps more widely scattered over the local waters on
Saturday. Scattered showers are expected this afternoon across the
northwestern quadrant of PR. Sea breeze convergence could contribute
to the expected shower development, but the activity is not expected
to cause significant flooding, though ponding of water in poor
drainage areas will not be ruled out. The latest guidance suggests a
relatively stable day on Friday, with morning showers across eastern
PR, but little to no rainfall during the rest of the day over the
local islands. Even though we will have near normal moisture, the
drier air will start to filter by the late morning into the early
afternoon, and the dry air advection could limit the afternoon
shower activity. On Saturday, most of the shower activity is
expected to occur across the local waters, and little to no shower
activity over land areas.

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

The most recent model guidance suggests a relatively drier weather
pattern, with model-estimated precipitable water vapor values of
1.2 inches or below prevailing during the long-term forecast
period. In this new solution, the strong polar trough and the
remnants of an old frontal boundary should remain well to the
north of the Caribbean region, having minimal impacts over the
area. If anything, a slight weakening of the mid-level ridge due
to the trough`s proximity and increased low-level moisture, with
the highest model-estimated precipitable water values of around
1.5 inches suggested for the cycle, could increase the potential
for showers on Monday. Even on the driest days, showers will favor
a seasonal advective pattern, dominated by overnight/early morning
showers moving over eastern Puerto Rico and the US Virgin Islands
at times. Afternoon convection will be limited to portions of the
interior and far western Puerto Rico through the cycle, with the
best chance for modest rainfall accumulations (around 0.25 inches
and possibly locally higher) on Monday. Nonetheless, the flood
threat will remain low. In contrast, the wind threat will remain
moderate, with the general wind flow exceeding 20 mph with higher
gusts through most of the cycle.


&&

.AVIATION...Mainly VFR conditions will prevail through the forecast
period. VCSH will affect TJSJ, TIST, and TJBQ until 17/14Z, but will
gradually increase up to around 20KT with to around 25KT thereafter.
Another round of showers would affect areas in and around TJBQ after
17/17Z, with VCSH likely and possible brief SHRA at the terminal,
which could cause TEMPO MVFR conds at some point between 17/17Z and
17/21Z.


&&

.MARINE...Moderate to fresh winds up to 20 knots and a weak small
northerly swell will maintain choppy to hazardous marine
conditions across most local waters, except coastal waters of
northern, southern, and western Puerto Rico. As a result, Small
Craft Advisories remain in effect. For beachgoers, a high risk of
rip currents also continues for beaches across the northwest to
northeast and southeast coast of Puerto Rico and most beaches of
Vieques, Culebra, and the US Virgin Islands.


&&

.FIRE WEATHER...Lack of wetting rains will further dry soils and
fuels across southern Puerto Rico, where KBDI values remain well
above 700, and 10-hour fuel moisture have ranged in the 9-10
percent in recent days. Satellite imagery indicated pockets of
drier air, with satellite-estimated precipitable water values as
low as 0.90 inches, approaching the region from the east. The
timing of these patches will be critical, causing relative
humidity values to fall into the lower-to-mid 40s during peak late
morning and early afternoon hours. At the same time, brisk
easterly winds will also affect the area, with local effects and
sea breeze variations causing winds to peak at 15-20 mph with
higher gusts. Given the expected weather conditions and current
state of soils and fuels, an elevated threat of wildfires is
anticipated, mainly across the southeastern coastal plains of
Puerto Rico. For this reason, a Fire Danger Statement has been
issued.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 87 75 87 75 / 30 40 30 10
STT 85 73 85 74 / 30 30 20 20