Caribbean - Central America Weather

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
506 AM AST Fri Mar 18 2022

.SYNOPSIS...A generally stable weather pattern with breezy
conditions will prevail through the weekend. At times, patches of
shallow moisture embedded in the trade winds will support isolated
to scattered shower activity, but relatively drier conditions
will persist during the next few days. Further drying of soils and
fuels and critically windy and drier conditions will support a
threat of wildfires, mainly across southeastern Puerto Rico, where
a Red Flag Warning is in effect through this afternoon. Brisky
winds and a fading small northerly swell will maintain choppy to
hazardous marine and surf zone conditions through the upcoming
weekend.


&&

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

Easterly winds will prevail through the short therm period, with
speeds of around 10 mph during the night, and up to 20 mph during
the day with occasional gusts are expected due to a surface high
pressure that will remain near the north central Atlantic as it
slowly moves east. The mid to upper levels continue to be fairly
stable, as a ridge of high pressure will prevail over the local
area, though an upper trough will start to move to our north by late
Sunday. The available moisture will remain near to below normal
through the short term period. The precipitable water will be below
normal today, being near normal this morning, but drying up by this
afternoon, then another increase in moisture will occur on Saturday,
then drying up again on Sunday. That said, the precipitable water
increase expected on Saturday will be most significant over the
local waters.

This pattern will favor brief isolated to scattered showers in the
morning hours across the USVI, and northern and eastern PR, but only
a slight chance of showers int he afternoon as the drier air moves
in. The increase in moisture on Saturday could cause more widely
scattered over the local waters through the day. Isolated showers
expected again on Sunday. The shower activity expected in the short
term period is not expected to cause flooding. However, there may be
brief periods on Saturday, especially early in the morning, where St
Croix may observe significant showers that could lead to ponding of
water. Also, a small portion of western PR could observe showers
that could cause ponding of water on Saturday afternoon. Otherwise,
no major hazard is expected.

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

Although moisture levels will remain at or below seasonal normals,
the most recent model guidance suggests a patchy weather pattern
dominating the area through the long-term forecast period, with
model-estimated precipitable water vapor values ranging between
0.90 and 1.40 inches. A strong polar trough and the remnants of an
old frontal boundary will remain well to the north of the
Caribbean region, but the trough`s proximity will force a mid-
level ridge to move westward into the western Caribbean on Monday.
This shift will briefly weaken the trade wind cap, allowing deeper
moisture to move into the area and the best chance for modest
rainfall accumulations around 0.25 inches and possibly locally
higher through late Monday night. After that, ridging will
gradually re-establishes over the northeastern Caribbean,
maintaining a strong trade wind cap inversion and hostile
conditions for deep convective development through the rest of the
forecast cycle. Nonetheless, patches of low-level moisture
embedded in the trade winds will support isolated to scattered
shower activity, following the seasonal shower pattern. Hence,
expect overnight/early morning showers moving over eastern Puerto
Rico and the US Virgin Islands at times, followed by limited
afternoon convective development over the interior and far western
sections of Puerto Rico. The flood threat will remain low, but
winds exceeding 20 mph with higher gusts will maintain a moderate
wind threat through most of the cycle.


&&

.AVIATION...VFR conditions will prevail through the forecast period.
VCSH will affect TJSJ, TIST, and TJBQ until 18/14Z. Winds of 10KT
will continue until 18/14Z, but will gradually increase up to around
20KT with gusts to 25KT. ISOL SHRA could affect areas in and around
TJBQ after 18/17Z, causing VCSH once again.


&&

.MARINE...Moderate to fresh winds up to 20 knots and a fading
northerly swell will maintain choppy to hazardous marine
conditions across most local waters, except coastal waters of
northern, southern, and western Puerto Rico. Small Craft
Advisories remain in effect but expect improving marine conditions
across coastal waters of eastern Puerto Rico, Vieques, Culebra,
and the northern US Virgin Islands by this afternoon. 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...Although fuels have remained somewhat wet and far
from fire danger thresholds, lack of wetting rains have supported
further during of soils across the southern coastal plains of
Puerto Rico, where KBDI values continue well into the 700s. Brisk
easterly winds will drive intermittent dry and moist air patches
across the local area. The next pocket of drier air, with
satellite-estimate precipitable water vapor values as low as 0.80
inches, is expected to reach the local islands during peak late
morning and early afternoon hours. The timing will be critical,
and relative humidity values are expected to fall into the mid to
upper 30s, while local effects and sea breeze variations will
promote winds exceeding 18 mph with gusts to around 30 mph. Given
the expected dry weather conditions and the current state of soils
and fuels, a critical fire weather conditions are anticipated,
with highest impact across the southeastern coastal plains of
Puerto Rico, where a Red Flag Warning is now in effect. For
details, please refer to the Red Flag Warning (RFWSJU) issued by
the National Weather Service, San Juan office.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 87 75 86 73 / 40 20 20 20
STT 85 73 85 72 / 20 20 20 20

[cycloneye]

Area Forecast Discussion...CORRECTED
National Weather Service San Juan PR
607 AM AST Sat Mar 19 2022

.SYNOPSIS...A generally stable weather pattern with breezy
conditions and limited shower activity will prevail during the
next few days. Patches of shallow moisture embedded in the trade
winds will support isolated to scattered shower activity from time
to time. Still, relatively drier conditions will persist through
the cycle, leading to further drying of soils and fuels, with the
potential of fire danger conditions. Brisk easterly trade winds
will maintain choppy to hazardous marine and surf zone conditions
through the rest of the weekend, gradually improving throughout
the workweek.


&&

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

Easterly winds will prevail through the short therm period, with
speeds of around 10 mph during the night and up to 20 mph during the
day over land areas, with occasional gusts due to surface high
pressures over the central Atlantic. The mid to upper levels
continue to be fairly stable, as a ridge of high pressure will
prevail over the local area. An upper trough will start to move to
our north by Monday, but will not cause too much instability over
the local area as we remain in the subsident side of the axis, that
said, the winds could get stronger in the upper levels, causing some
divergence aloft, but the guidance precip solutions do not seem to
reflect any significant increase in forecast rainfall. The available
moisture will remain near normal today, but will be below normal
from Sunday onward.

This pattern will continue to favor brief isolated to scattered
showers in the morning hours across the USVI, and northern and
eastern PR in the morning hours, while scattered showers are
expected in the afternoon hours across a few sectors of eastern and
western PR, as well as the USVI. However, the showers that could
develop across western PR can be moderate to heavy at times due to
the influence of the sea breeze convergence. For that reason,
especially today, ponding of water could occur in areas of poor
drainage over western PR. The near to slightly above normal moisture
expected over the local waters today could keep widely scattered
showers through the day. For Sunday and Monday, as drier air moves
in, the chances of significant rainfall diminishes and no
significant hazard is expected for those days with respect to
rainfall.

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

Although the most recent model guidance suggests that moisture
levels will remain at or below seasonal normals, this new guidance
suggests an even drier scenario than previous solutions. Mid-
level ridging will gradually re-establish over the northeastern
Caribbean, becoming the dominant feature and maintaining hostile
conditions for deep convective development through the forecast
cycle. At lower levels, moderate to fresh easterly trade winds of
15-20 mph will prevail through the workweek. Under this steering
flow, intermittent patches of relatively dry and moist air will
stream across the area, causing precipitable water values to vary
in short periods. So far, the wettest period, with the best chance
for showers, is expected on Friday, when precipitable water
values are forecast to peak around 1.40 inches. Otherwise,
precipitable water values should remain under 1.2 inches and below
seasonal normal moisture levels, with the lowest precipitable
water values around 0.90 inches expected by Thursday morning.
Except for the eastern and far western sections of Puerto Rico and
the US Virgin Islands, where showers may bring some rains, the
rest of the forecast area will observe fair weather conditions
with limited to no shower activity. The diurnal temperature cycle
will warm up as we move further into the spring season, with
daytime highs reaching the lower 90s at some locations. The
expected scenario with limited wetting rains and further drying of
soils and fuels, strong winds, low relative humidity, and warm
temperatures could support elevated to critical fire danger
conditions, mainly across fire-prone locations across southeastern
Puerto Rico.


&&

.AVIATION...VFR conditions will prevail through the forecast period.
VCSH will affect TJSJ, TIST, and TJBQ until 19/14Z. Winds of 10KT
will continue until 19/14Z, but will gradually increase up to around
20KT with gusts to 25KT. ISOL SHRA could affect areas in and around
TJBQ after 19/17Z, causing VCSH once again.


&&

.MARINE...Moderate to fresh winds up to 20 knots will maintain
choppy to hazardous marine conditions through late Sunday night,
mainly across the offshore waters and local passages, where Small
Craft Advisories are in place. Marine conditions will improve
early next week, but small craft operators should exercise caution
due to choppy seas up to 6 feet. For beachgoers, a high risk of
rip currents remains for beaches across the northwest to the
northeast and the southeast coasts of Puerto Rico and some beaches
of Vieques, Culebra, and St Croix.


&&

.FIRE WEATHER...A relatively dry weather pattern with no signs of
significant wetting rains will continue to affect the region, but
patches of shallow moisture will maintain moisture levels far from
fire danger conditions from time to time. Further drying of soils
and fuels continues, with the most recent KBDI well into the 700s
and 10-hour fuel moisture falling to 8 percent at Camp Santiago in
recent days. Brisk easterly trade winds will continue to affect
the area, with local effects and sea breeze variations producing
winds of 15-25 mph with gusts to around 30 mph during the late
morning and early afternoon hours. Although this scenario calls
for elevated fire danger conditions, an extended area of shallow
moisture expected to reach the local islands later today, with
satellite-estimated precipitable water values of 1.1-1.3 inches,
should maintain high relative humidity and fuel moisture levels.
Still, a Fire Danger Statement for elevated fire danger conditions
could be issued later today if conditions warrant.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 85 73 86 73 / 30 20 20 30
STT 85 72 85 73 / 30 20 20 30

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
452 AM AST Sun Mar 20 2022

.SYNOPSIS...A series of surface high pressures across the Atlantic
will keep easterly winds for the next several days. It will be
breezy today, but winds will diminish slightly early in the
workweek, but will be breezy again in the mid to the latter part
of the week. In the upper levels, a trough will be passing
through, causing stronger winds aloft, especially for late Monday
through Wednesday, but for the most part the local islands will
remain in the subsident side of the trough. By next weekend,
another upper level trough may be better positioned to cause
instability over the local islands. The pattern expected over the
next several days is for brief showers during the overnight and
early morning hours, affecting the local waters, USVI, and north
and eastern PR, then afternoon showers that could develop across
western PR in areas of sea breeze convergence with isolated
showers elsewhere. But overall, below normal moisture is expected,
so the shower activity is expected to be relatively brief and
limited in coverage.

&&

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

Mid-level high pressure will continue to dominate the local weather
conditions the rest of the weekend and early next week. This is
maintaining a strong cap that is trapping most of the moisture below
700MB or the first 3 km. Low-level winds will continue fairly strong
with 0-1km avg winds around 20 kt based on the 00Z TJSJ sounding.
Surface high-pressure north of the islands will continue to promote
fresh winds across the region through tonight gradually subsiding
into early next week. In terms of moisture content, it will range
between 0.8 and 1.2 inches of precipitable water through Tuesday,
those values are below to near-normal for this time of the year.
Under the influence of a generally stable pattern and relatively
strong trade winds, light rainfall accumulation is anticipated over
the next few days. The areas that will likely experience light
passing showers could be portions of the U.S. Virgin Islands and the
east and northeast sections of Puerto Rico during the overnight
hours and early in the morning. Afternoon convection if any will
affect Mayaguez and surrounding municipalities. Elsewhere, mostly
sunny skies with minimal rainfall activity are forecast at this
time.

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

Easterly winds will continue into the long term period, with
moderate winds on Wednesday, but getting stronger by late
Wednesday. These stronger breezes are expected into next weekend.
For the most part, the mid and upper levels are going to be stable
over the local islands, with a ridge dominating most of the long
term period. There are stronger winds aloft expected on Wednesday
with an upper trough to our east, which normally causes divergence
and promotes shower activity, but the available moisture is
expected to be below normal, and the axis of the trough, being to
our east, puts us in the subsident side and therefore limiting
significant shower activity. For the rest of the long term period,
below to near normal moisture is to be expected with the moderate
to breezy easterly winds. Therefore, generally fair weather is
expected with the exception of the brief showers that will affect
the local islands overnight and in the morning hours. Also, every
afternoon, there will be a chance of showers across western PR in
areas of sea breeze convergence. Given the expected patterns
though, the afternoon shower activity is not expected to be too
significant, and deep convection is not expected. In terms of
temperatures, near normal max and min temps are expected through
the long term period.

&&

.AVIATION...Aviation...VFR conditions will prevail thru the forecast period.
VCSH possible at TJSJ, TIST, and TJBQ thru mid-morning. SHRA could
develop near TJMZ and may result in VCSH near TJBQ between 17Z-21Z.
East winds of 15-20KT with gusts to 25KT will persist below FL150.


&&

.MARINE...Hazardous seas up to 7 feet are expected until early
this afternoon across the offshore waters and local passages,
except the Anegada passage, which will have seas up to 6 feet
starting this morning. There is still a small craft advisory in
effect for the local waters until 2 PM this afternoon. Seas are
expected to remain choppy but up to 6 feet thereafter and into
the upcoming workweek. There is a high risk of rip currents for
the north and southeast beaches of PR, as well as many beaches of
Vieques, Culebra, and the USVI. Most of the local beaches will
have either a moderate or a high risk of rip currents for the next
several days.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 85 72 84 73 / 30 30 30 30
STT 85 72 83 72 / 30 30 30 20

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
457 AM AST Mon Mar 21 2022

.SYNOPSIS...Northeasterly flow will prevail today through Tuesday
as the ridge builds across the west Atlantic, and a cold front
stalls and weakens well north of the region. Breezy conditions
will return again by midweek in response to a building high north
of the region. An upper level short wave trough will cross the
west Atlantic and slightly erode the mid level ridge. Late in the
week, the mid level ridge will hold maintaining relatively stable
conditions aloft. All in all, a seasonal pattern will continue with
a cool advective weather pattern to persist across the forecast
area.

&&

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

Recent GFS model guidance initialized well with the present
conditions and suggest the general moderate east northeast low level
wind flow to continue today. Satellite derived total precipitable
water values showed a relatively dry airmass with overall values of
one inch or less. Latest guidance and satellite imagery however
continued to suggest that patches of shallow moisture with mostly
light to moderate showers will move across the region. That said,
early morning passing showers can be expected over the coastal
waters and will continue to reach eastern Puerto Rico and the U.S.
Virgin Islands from time to time. No significant rainfall
accumulations are expected. Limited afternoon shower development is
expected and should be focused mainly over the interior and western
portions of Puerto Rico, and mostly down-wind of the U.S. Virgin
Islands however a some showers may reach a few of the islands later
in the afternoon. On Tuesday, the upper ridge will be reinforced
once again, and the surface high pressure will build and migrate
eastward across the west Atlantic. This will result in increasing
trade winds with a similar weather pattern forecast,except for the
breezy conditions along with a quick surge of trade wind moisture
expected early Tuesday. By Wednesday lesser moisture advection with
a mostly fair weather pattern and limited afternoon shower activity.
Moderate to locally strong easterly winds will persist along with
the advective pattern of shallow moisture and quick passing early
morning showers. No significant rainfall accumulations as so far
forecast for the period.

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

Surface high pressure across the northwestern Atlantic will lead
to breezy conditions the second part of the week. Wind will remain
mainly easterly Thursday and Friday, veering to the east southeast
during the weekend and early next week as a pre-frontal trough
approaches from the northwest. At mid to upper level, the proximity
of high pressure ridges at 700MB and 500MB will keep the environment
fairly dry late in the period. However, an area of low-level
convergence embedded in the trade winds will guarantee periods of
scattered showers from time to time, especially between Friday
afternoon and Sunday morning. Although the overall moisture will
remain near normal during this period, little perturbations in the
trade winds will enhance the low-level convergence favoring trade
wind showers across the windward areas early in the morning followed
by shallow convection over the west and northwest Puerto Rico each
afternoon. Conditions will become drier and more stable Monday and
Tuesday next week prior to the arrival of a pre-frontal trough by
mid-week next week. There is still some uncertainty in the timing
of those features in the long term, therefore the forecast will
likely be adjusted over the next few days.

&&

.AVIATION...VFR conds will persist durg prd. Low level wnds will
continue to transport SCT cloud lyrs nr FL028...FL050 ovr regional
waters and en route btw islands with mostly Isold SHRA. SFC wnds
light and variable bcmg E-NE 12 to 18 knots with higher gusts and
sea breeze variations aft 21/14Z. VCSH psbl at TJSJ/TJBQ/TJMZ 18Z-
22Z.

&&

.MARINE...Moderate easterly winds and seas of 4-6 feet will
prevail early in the week. Marine conditions will deteriorate
once again by mid-week as wind increases producing choppy seas
the second part of the week. The high risk of rip currents across
the north and east-facing beaches of Puerto Rico and most of the
beaches in Culebra, Vieques, and the U.S. Virgin Islands will
likely continue most of the workweek. We could extend the rip
current statement later today or tomorrow if models continue to
suggest higher wind-driven seas in the mid to long term.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 84 71 84 74 / 30 30 10 20
STT 84 75 84 76 / 40 20 10 10

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
433 AM AST Tue Mar 22 2022

.SYNOPSIS...East northeast wind flow will prevail today as the
surface ridge spreads eastward across the west Atlantic, while a
cold front well north of the region continued to weaken and become
sheared. Increasing trade winds and breezy condtions are still
expected to return again by Wednesday and through the end or the
work week in response to a building high north of the region. A
mid to upper level ridge will gradually build across the region
today and through the end of the week thus maintaining relatively
stable and subsident conditions aloft. A overall seasonal weather
pattern is forecast to continue with the cool advective weather
pattern to persist across the forecast area for the next several
days.

&&

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

Latest model guidance suggest only minor changes from previous
version with still no significant weather features forecast to
affect the region during the short term period. GFS model guidance
continue to initialized well and suggest a general northeast low
level wind flow to persist today then become more easterly and
increase by the end of the period as the local pressure gradient
tightens. The blended satellite derived total precipitable water
values showed overall values around one inch or just below over most
of the areas, except for just east of the U.S. Virgin Islands where
values ranged between 1.25-1.50 inches. This is associated with a
patch of shallow moisture/easterly perturbation which will cross the
region later today but move mainly along the southern portions of
the forecast area. That said, limited early morning showers can be
expected over the coastal waters but some may reach eastern Puerto
Rico and especially the island of St Croix from time to time.
However, no significant rainfall accumulations are expected. Locally
and diurnally induced a afternoon shower development should be
focused mainly over the central interior and western portions of
Puerto Rico, and mostly on the west end or just down-wind of the
U.S. Virgin Islands.

By Wednesday and Thursday lesser moisture advection with a mostly
fair weather pattern and limited afternoon shower activity is so far
expected. Moderate to locally strong easterly winds are forecast as
the local pressure gradient tightens and therefore breezy conditions
can be expected as previously mentioned along with the cool
advective pattern of shallow quick passing moisture and a few early
morning showers. This will be followed by limited afternoon
convection each day mainly over the west end of the islands and
downstream in the form of streamers. A few showers in and around
afternoon showers in and around the San Juan Metro cannot be ruled
out but will of short duration. So far still no significant
rainfall accumulations are forecast for the short term period.

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

Breezy conditions associated with a surface high-pressure north-
northeast of the local islands will persist through Friday. The
main direction of the trade winds will be easterly late in the
workweek. Then, the trade winds weakenas veer to east southeast
during the weekend. Follow by a southeasterly flow early next week
as a frontal boundary stalls to our north-northwest. High-
pressure ridge aloft centered over the central Atlantic will keep
the mid to upper levels dry and relatively stable most of the
period. By midweek next week, operational models suggest the
arrival of an upper-leveltrough that will likely enhance the
instability across the local area.

In terms of moisture content, precipitable water values remain
below normal through Friday. However, strong trade winds late in
the workweek could favor a boost in trade wind showers across the
windward areas early in the morning. But rainfall accumulations
will be generally light as strong winds will push the showers
quickly across the islands. Then, moisture surges on Saturdayas
an area of low- level convergence moves over the northeast
Caribbean. This will lead to a few rounds of scattered showers
during the day of Saturday. Then, a drier and more stable air mass
returned to the area Sunday into early next week. Conditions may
change by midweek next week when moisture deepens and instability
increases in response to an approaching upper-level trough.

&&

.AVIATION...VFR conds will persist thru the fcst prd. Sfc wnds will
continue from ESE at less than 10 kt, increasing to btw 10-15 knots
with higher gusts and sea breeze variations aft 22/14Z. Low level
cloud cover will slightly increase ovr the Caribbean waters in and
TISX and Ern PR durg the rest of the morning hours w/SCT ocnl BKN
lyrs nr FL025...FL050...FL080...along quick passing Isold-SCT SHRA.
VCSH at TIST/TISX and TJSJ til 14Z....with Isold-SCT SHRA fcst to
develop btwn 17Z-22z ovr the ctrl MTN range and W PR durg the rest
of the day.

&&

.MARINE...Local buoys from CariCOOS are showing that the seas are
gradually subsiding across the nearshore waters. NWPS, our wave
model, is overestimating the seas slightly, as a result, we made
the corresponding adjustment in the wave fields. Based on those
adjustments, the risk of rip currents is now moderate through
Wednesday. Conditions will deteriorate again late Wednesday night
into Thursday as winds increases to around 20 knots and seas will
build to 7 feet.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 84 74 84 72 / 20 30 30 30
STT 85 72 85 73 / 30 30 30 30

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
446 AM AST Wed Mar 23 2022

.SYNOPSIS...Northeast winds will gradually become more easterly
and increase today through the end of the period, as a surface
ridge will spread eastward across the west Atlantic while
tightening the local pressure gradient. A mid to upper level ridge
will build and hold across the area through the end of the work
week to maintain dry and stable conditions aloft. Seasonal
weather conditions will persist with the cool advective weather
pattern expected across the forecast area for the next several
days. As a result of the increasing winds, seas will become choppy
and hazardous for portions of the local waters later tonight and
continue through the period.

&&

.SHORT TERM...Wednesday through Friday...

Latest model guidance remain in agreement with the present weather
pattern and short term forecast. All suggest the northeast winds
wind will persist today, but will gradually become more easterly and
increase by Thursday. This in turn will promote breezy conditions
across the area. Satellite derived total precipitable water
(PWAT) as well as the model forecast both suggest a gradual drying
trend with values to range between 1.0 or slightly less to near
1.25 inches as the patch of low level moisture now exiting the
region will continue to diminish. However, expect sufficient
lingering moisture across the region to favor locally and
diurnally induced afternoon showers in and around the islands.
This activity should be mainly focused over the interior and west
sections of Puerto Rico with lesser activity around the U.S.
Virgin Islands, where mostly sunny skies and limited shower
activity if any will prevail.

For Thursday and Friday expect lesser moisture advection as the
upper level ridge builds overhead. The increasing trade winds will
continue to bring occasional patches of trade wind moisture to the
region mainly during the late evening and early morning hours
followed by mostly fair weather skies during the day and limited
locally and diurnally induced afternoon shower activity each day.
Therefore, the cool advective pattern of shallow quick passing
moisture and a few embedded early morning showers will be the
trend, followed by limited afternoon convection mainly over the
west interior of Puerto Rico and on the west end and downstream
of the islands in the form of streamers. Few afternoon showers of
short duration will remain possible in and around the San Juan
Metro cannot be ruled out but will of short duration. Still no
significant rainfall accumulations are forecast for the short term
period.

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

The trade winds will weaken as they veer east-southeast during
the weekend. Early in the week a southerly flow will be seen as a
frontal boundary sits to the north-northwest of the island. High
pressure far north of Puerto Rico will maintain the mid to upper
levels dry and relatively stable throughout most of the period. By
midweek next week, operational models suggest the arrival of an
upper-level trough that most likely will enhance instability
across the local area.

In terms of moisture content, precipitable water values will surge
on Saturday due to the area of low-level convergence that will
move over the northeast Caribbean. This will cause a few rounds of
scattered showers during the day on Saturday. Later on, a drier
and more stable air mass returns to the area by Sunday into
Monday. Unsettled conditions are expected by midweek next week as
an approaching upper-level trough moves closer to the islands.
This may result in more organized convection across the northeast
Caribbean due to increasing moisture and instability associated
with the upper trough.

&&

.AVIATION...VFR conds durg prd. SCT ocnl BKN lyrs nr FL025...
FL050...FL080 with Isold SHRA ovr regional waters and en route btw
islands. SFC wnds will be fm ENE at 10 kt or less, increasing to
15-20 knots with higher gusts and sea breeze variations aft
23/14Z. ISOLD-SCT SHRA fcst btwn 23/17Z-22z mainly ovr the ctrl
mountain range and W PR. No other sig operational wx impacts attm.

&&

.MARINE...Seas of 4 to 6 feet and winds of 15 to 20 knots are expected
across the offshore waters today. However, buoys observations are
indicating seas from 2 to 4 feet in the near shore waters.
Conditions will deteriorate tonight into Thursday with seas
increasing to 7 feet across the offshore Atlantic and Mona
Passage. Therefore, Small Craft Advisories remain in effect from
tonight through Thursday night for the areas mentioned.

Currently, there is a high risk of rip currents for the northwest
and north central beaches of Puerto Rico and northeast beaches of
Saint Croix. The northeast and eastern coasts of PR, including
Vieques and Culebra and northern USVI will be added to the high
risk of rip currents tonight.

&&

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

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
541 AM AST Thu Mar 24 2022

.SYNOPSIS...Locally strong trade winds will persist through Friday
favoring a boost in trade wind showers across the windward areas
each morning. But rainfall accumulations will be generally light as
strong winds will push the showers quickly across the islands. Then,
Saturday looks a bit wetter as the overall moisture increase followed
by the driestday of the forecast period on Sunday. Unsettled conditions
are possible midweek next week when moisture deepens and instability
increases in response to an approaching upper- level trough.

&&

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

Breezy conditions associated with a surface high-pressure north-
northeast of the local islands will continue over the next 24 hours.
Satellite-derived winds suggest pocketsof 20-25 knots across the
northeast Caribbean. Also, radar-derived winds indicated that the
clouds and showers were moving westward at about 20 knots over the
local area. These locally strongtrade winds will continue to push
the passing showersfairly quickly across the local islands limiting
the rainfall accumulations. The precipitable water will remain below
normal through Friday. Under these conditions, the shower activity
will be focusedon the windward areas, especially overnight and
early in the morning. Afternoon showers over western Puerto Rico may
affect Mayaguez and vicinity but they will move quickly over the
Mona Passage due to the strong steering flow.

The mid-level ridge will continue to dominate the rest of the week.
This will keep all the moisture trapped at low levels with the mid-
levels being fairly dry and stable. The main change on Friday and
Saturday is that the winds will veer from the east-southeast to
southeast while gradually subside to around 10-15 knots. As the wind
decreases, sea breezes and local effects will be more important in
the development of afternoon showers. For Friday, moisture remains
below normal, therefore the afternoon convection will be limited to
the northwest portions of Puerto Rico. Then, moisture returns to
normal levelson Saturday. This will combine with an area of low-
level convergence that could move near the forecast area, leading to
a few rounds of scattered showers during the day.

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

The trade winds will continue to weaken as they veer east-southeast
on Sunday with improving conditions expected through at least
Tuesday. A light southerly flow is expected as a frontal boundary
relocates to the north-northwest of Puerto Rico and a weak trough
develops across the region. The mid to upper levels will continue to
have relatively dry and stable condition into early part of the week
due to the high pressure aloft. The latest model guidance continued
to suggest a gradual erosion of the ridge, as an approaching upper-
level trough will enhance instability across the area by midweek.
Wednesday through Thursday the upper-level trough is forecast to be
amplified across the area.

The overall moisture will return to values below normal by Sunday
into early next week with this being the driest day of the
period. Moisture content will gradually surge again on Tuesday
through mid-week as the upper trough moves across the forecast
area and low-level moisture increases. This pattern will result
in increased convection and instability across the area.

By Friday, expect a return of a more seasonal pattern as winds
become more east to northeast and the mid to upper ridge gradually
builds across the region, while the surface high reestablishes
across the west Atlantic. This will result in more typical early
morning and afternoon shower activity with mostly fair weather
condition across the region during the day.

&&

.AVIATION...VFR conditions will prevail through the forecast
period. Quick passing SHRA will affect the terminals at times
causing little or operational impacts. Low level winds will
continue from the east at around 15-25 kts below FL150. Occasional
wind gust up to 30 knots can not be ruled out.

&&

.MARINE...Seas of 5 to 7 feet and winds of 15 to 20 knots are
expected across the offshore waters today. However, buoys
observations are showing seas from 3 to 5 feet in the near shore
waters. Today conditions will continue to deteriorate with seas up
to 7 feet across the offshore Atlantic and Caribbean waters and
local passages. Therefore, Small Craft Advisories remain in effect
through tonight for the areas mentioned.

Currently, there is a high risk of rip currents for the northern and
southeastern facing beaches of Puerto Rico, including the
northeastern and southeastern beaches of Vieques, all beaches of
Culebra and the USVI.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 84 72 85 73 / 40 20 40 20
STT 84 71 84 73 / 30 30 40 30

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
417 AM AST Fri Mar 25 2022

.SYNOPSIS...Breezy conditions with passing showers will affect the
local area at times today, but significant rainfall, capable of
producing flooding is not anticipated. A generally tranquil pattern
is anticipated for the weekend, but unsettled weather, with an
increase in the frequency of showers is in the forecast for mid-
week. Choppy seas are expected to prevail through Saturday,
gradually diminish by Sunday into early next week.

&&

.SHORT TERM...Today through Sunday...
A mid-level ridge centered north of the local islands will continue
to dominate the local weather. This is creating a trade wind cap
inversion around 800 to 750 mb, with mid-level relative humidities
at around below 40% for Friday. At the surface, a high pressure over
the central Atlantic will maintain the trade winds out of the east-
southeast at 15 to 20 mph. This pattern will favor all the moisture
to remain trapped at the lower levels. Total Precipitable Water from
GOES-16 show an small pocket of enhanced moisture advancing into the
Leeward Islands. The global models indicate that this area of
showers will move into the eastern sections of the forecast area by
the morning hours, bringing passing showers into the region. In the
afternoon, the available moisture should generate showers across the
interior and northwestern Puerto Rico, while additional activity
will be possible across the northeast and the San Juan metro area.

The mid-level ridge will begin to flatten out on Saturday as a
trough exists the eastern coast of the United States. However, the
environmental conditions will not change too much, as the mid-levels
will continue to be very dry. The surface high pressure will also
continue to migrates eastward, causing the winds to acquire a more
southeasterly component. In general, the trade winds could drag
additional patches of shallow moisture across the area with
occasional showers posible. On Sunday, as a cold front advances over
Cuba and the Bahamas, a prefrontal trough should develop over the
eastern Caribbean, crossing the area through the day. This feature
should act to increase low-level converge, but so far, the guidance
indicate that the lack of moisture should inhibit any strong
activity from developing.

.LONG TERM...Monday through Saturday...
The latest model continue to forecast a weakening in the trade winds
as they continue veering east-southeast on Monday. A light southerly
flow will be seen as a frontal boundary moves to the north-northwest
of Puerto Rico and a weak trough develops across the region. The mid
to upper levels continue to suggest relatively dry and stable
condition into early part of the week due to the high pressure
aloft. The most recent model guidance is showing a gradual weakening
of the ridge as an upper-level trough brings instability across the
area by early midweek. Wednesday through Thursday the upper-level
trough is forecast to be amplified across the area bringing wetter
conditions through the rest of the week into the weekend.

Moisture content will increase again by mid-week as the upper trough
moves across the forecast area and low-level moisture increases.
This pattern will result in a surge in convection and instability
across the area.

By Saturday, expect a drier trend as the mid to upper level ridge
starts to build over the region. A surface high will reestablish
across the west Atlantic early this weekend resulting in a typical
seasonal pattern

&&

.AVIATION...Mainly VFR conditions expected. VCSH are expected for
TJSJ and the USVI terminals after 14Z, and for TJBQ after 17Z. This
could result in brief periods of reduced VIS and low ceilings. Winds
will pick up after 14Z, coming out of the ESE at 15 to 20 knots,
with stronger gusts.

&&

.MARINE...Seas up to 7 feet and winds between 15 to 20 knots are
expected across the offshore waters through this morning.
Conditions will gradually improve later today, but seas will
remain up to 6 feet across the offshore Atlantic and Caribbean
waters and local passages through tomorrow. There is a high risk
of rip currents for the northern and southeastern facing beaches
of Puerto Rico, including the beaches of Vieques, Culebra and for
some beaches of northern and eastern St. Croix.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 85 72 87 72 / 40 20 20 10
STT 84 72 83 72 / 50 30 30 10

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
419 AM AST Sun Mar 27 2022

.SYNOPSIS...
Generally fair weather with only occasional showers is expected
through the weekend. Conditions are expected to become more
favorable for showers by midweek, however. Seas will remain below
5 feet this weekend, but could become choppy to hazardous on
Wednesday and Thursday.

&&

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

A cold front over the western Atlantic extending from the eastern
tip of Cuba will advance east southeastward and force the high north
northeast of the local area ahead of it. By Monday the cold front
will have pushed into Haiti and the northwestern corner of the
Dominican Republic where it will stall. This pattern will allow a
weak inverted trough to form at lower levels over the local area
today and drift westward on Monday. Winds in the trough will
generally be less than 15 knots everywhere in the forecast area but
will increase somewhat on Tuesday as the trough leaves the area.
Limited moisture will continue through Tuesday afternoon and the
marine layer will shrink from around 10 kft to around 5 kft. This
will suppress all but the local orographic shallow passing showers.

High pressure at mid levels is now about 1100 miles east of San
Juan, Puerto Rico and will remain there through at least Tuesday. At
upper levels, the ridge over the area moved into the Leeward Islands
overnight and will continue to drift eastward into the tropical
Atlantic Monday and Tuesday. A trough will approach Cuba on Tuesday
and bring increasing west southwest winds aloft.

.LONG TERM...Wednesday through Monday...
The axis of the upper level trough will be located between Cuba
and Hispaniola on Wednesday and just west of Puerto Rico on
Thursday, with upper level winds shifting from the southwest. This
pattern results in divergence aloft, which is favorable for
shower production across the area. At the surface, a cold front
will be positioned to the north of the area, and this system
should not cross the local islands, but will allow for low level
moisture to flow from the east across Puerto Rico and the U.S.
Virgin Islands. In fact, the GFS-forecast soundings indicate the
columnar moisture will increase a little, with mid-level relative
humidities increasing to around 60%, although with precipitable
water values near climatological levels. By Thursday, the cold
front begins to dissipate while a surface high pressure just
behind it migrates westward. This will cause the trade winds to
increase to about 20 mph, still out of the east. At the upper
levels, the trough will remain in a position favorable to support
shower development across the area. Both days, conditions appear
favorable for showers and even isolated thunderstorm formation
across the area. Throughout the day, the activity should focus
over the eastern municipalities of Puerto Rico and may also move
over the Virgin Islands. In the afternoon, convective development
is anticipated for the interior and western sections of Puerto
Rico.

By Friday, the trade winds will remain moderate, but the environment
will become drier, as a mid-level ridge begins to build over the
western Caribbean. As the surface high pressure continues it way
into the eastern Atlantic, the pressure gradient will relax, and
winds will become lighter, at about 15 knots on Saturday and 10
knots on Sunday and Monday. Throughout the weekend and early next
week, the rain activity appears to be limited, with only small
patches of moisture reaching the area from time to time.


&&

.AVIATION...Sfc winds will be land breezes less than 6 knots till
26/13Z then ESE sfc flow will dvlp at 5 to 12 knots with sea
breeze intrusions. VFR conditions will prevail through the
forecast period over land areas. Aft 26/16Z SHRA to dvlp
downstream from El Yunque and over some parts of the Cordillera
Central with brief MVFR conds and mtn topping. SHRA expected to
dsipt ovr land by 26/22Z. The USVI should see fair weather conds.

&&

.MARINE...
Light winds out of the southeast should prevail through early in
the workweek, with seas of 5 feet or less. By mid-week, increasing
winds along with a northerly swell should result in choppy to
hazardous seas across the offshore waters and passages. For the
beaches, the risk of rip currents is moderate along most of the
local area.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 85 72 85 73 / 20 0 20 30
STT 84 72 84 72 / 10 0 10 20

[cycloneye]

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

.SYNOPSIS...With a cold front nearly stationary to the north and
northwest and a weak trough over the area, shower activity will
be modest and winds will be generally lighter than usual. A
shortwave upper level trough will pass through on Thursday and a
high pressure will build over the Western Atlantic to bring
windier condtions and more showers Wednesday through Friday
followed by weakening winds and only passing showers through
Monday of next week.

&&

.SHORT TERM...Today through Wednesday...
A cold front crossing Hispaniola will induce a surface trough over
the area, but the front itself should not reach the local islands.
The mid-levels will continue dry, with a trade wind cap inversion
around 700 mb, due to a mid-level ridge across the eastern Atlantic.
The surface trough will result in a light wind flow, at 5 to 10
knots, and will enhance low level moisture convergence. On the other
hand, precipitable water values should be below normal, at 1.0 to
1.1 inches, as indicated by the GFS-forecast soundings and recent
satellite-derived products. As the axis of the surface trough moves
across the islands, some showers should fire up over the waters
around the Virgin Islands and eastern Puerto Rico, with local
effects aiding in convection across the interior and western Puerto
Rico this afternoon. With unfavorable conditions aloft,
accumulations are expected to be moderate, and in general,
remaining below one inch.

By Tuesday, an upper level trough will dig into the western
Caribbean, making the upper level winds shift from the southwest,
which creates divergence aloft. At the lower levels, a high
pressure west of the cold front will cause winds to shift from the
northeast and become a little bit stronger, at 10 to 15 knots.
Moisture is not expected to increase, and should remain below
normal, but with better conditions aloft, afternoon convection is
expected to be stronger, once again focusing across the interior
and western Puerto Rico. Finally, on Wednesday, columnar moisture
will increase all the way into 600 mb, with increasing instability
and mid-level temperatures at around -7 degree Celsius. In
general, the pattern will be similar, with the strongest activity
again in the interior and west, and isolated thunderstorms cannot
be ruled out.

.LONG TERM...Thursday through Monday...
On Thursday, the cold front will be nearly as far south as it
will be getting at around 21 degrees north, driven by the high
pressure in the western Atlantic to the north northwest. Patches
of moisture south of the front in the more moist air mass will
move across the forecast area. Friday through Monday, moisture
diminishes and becomes considerably less at 700 mb and only patchy
below. This will lead to our typical diurnal pattern of late
night and early morning shallow passing showers over eastern
Puerto Rico and around the U.S. Virgin Islands and showers over
western and interior Puerto Rico during the afternoon hours each
day. Flow will become more southeast with some random variations
during the period that will cause the north coast and in
particular the greater San Juan and Bayamon Metropolitan area to
become a little warmer each day.

At upper levels a sharp short wave trough will move through
Thursday night and should enhance the shower activity somewhat.
Then high pressure over the central Caribbean will flatten out and
produce generally light westerly flow through the rest of the
period. The mid level pattern will be similar, but with lighter
winds.

&&

.AVIATION...VFR conditions are expected to prevail through the
forecast period. SHRA could develop in the interior, resulting in
mountain obscurations after 28/17Z. Winds will be light until
28/12Z, then out of the ESE at 4 to 10 knots, with stronger gusts
due to sea breeze variations.

&&

.MARINE...Winds between 5 to 10 knots from the east should prevail for Monday,
with calmer seas of 5 feet or less. Starting Tuesday and continuing
through the week, winds start to increase and the introduction of a
northerly swell will increase sea heights, potentially creating
hazardous conditions. Currently for the beaches, the risk of rip
currents is moderate except around San Juan today and northern
coasts and the eastern tip of Saint Croix.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 84 73 84 73 / 10 40 20 50
STT 83 72 83 73 / 20 20 40 40

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
539 AM AST Tue Mar 29 2022

.SYNOPSIS...A stalled cold front just into Hispaniola to our
northwest will bring some shower activity in light easterly flow
to the area today and Wednesday. Increasing winds will peak on
Thursday and produce some hazardous seas and increasing areas of
high rip current risk. A passing upper level trough on Thursday
night and Friday with patches of low level moisture will keep
showers in the forecast. Winds will moderate somewhat during the
weekend but rapidly passing showers will continue.

&&

.SHORT TERM...Today through Thursday...
An upper level trough will continue to exit the eastern coast of the
United States, while a ridge is positioned over the central
Atlantic. These features are promoting a southwesterly flow at
upper levels, that results in divergence aloft. At lower levels,
a cold front will remain over Hispaniola, without crossing the
local islands, while a surface high pressure generates an east-
northeast wind flow, with a low level steering flow of 10 to 14
knots. Even without moving directly over the area, the front will
be close enough to aid with low level convergence. Combining these
factors, the result should be the development of showers across
the interior and west-southwest Puerto Rico. Showers are expected
to be moderate to locally strong, and urban and small stream
flooding cannot be ruled out.

On Wednesday and Thursday, the upper level trough digs into the
western Caribbean and begins moving eastward, while the surface high
pressure continues migrating eastward. The pressure gradient will
tighten, increasing low level winds, out of the east-northeast at 15
to 20 knots. Low level patches of moisture will continue to move
across the islands, which, in combination with the trough, should
help to develop another round of showers for the interior and west.
However, since the wind flow is expected to be stronger, showers
should move more quickly, leaving less rainfall accumulation over
the area. Additionally, showers embedded in the trade winds will
make their way into eastern Puerto Rico and the U.S. Virgin
Islands at times, especially during the overnight and early
morning hours. Although this pattern could disrupt some outdoor
activities, it is not expected to be significant enough to cause
flooding.


.LONG TERM...Friday through Tuesday...
High pressure in the west central Atlantic will move east
southeast during the period to within 350 miles northwest of the
Canary Islands. This allows a cold front to move off the
southeastern coast of the United States and settle to within 500
miles north of Puerto Rico by Tuesday. The old front will have
dissipated in place north and northeast of the area during the
week this week. This leaves local effects in moderate trade wind
flow the main driver of weather across the islands. Although
overall moisture deteriorates through Friday night, from Saturday
through Tuesday, moisture varies a lot and the maximum on Monday
will be over 1.7 inches of precipitable water. Hence, patches or
areas of very good moisture will cross through the area to enhance
shower activity all in the general normal of overnight and early
morning showers in eastern Puerto Rico and around the U.S. Virgin
Islands with afternoon convection in western and interior Puerto
Rico.

At upper levels a sharp short wave trough will move through
Thursday night and Friday and should enhance the shower activity
somewhat. Then high pressure over the southwestern Caribbean will
flatten out and produce generally moderate westerly flow of 30-50
knots increasing through the weekend and early next week. The mid
level pattern will be similar, but with lighter winds and a weak
trough east to west over the middle of the Caribbean.

&&

.AVIATION...Mainly VFR conditions are expected to prevail through
the forecast period. VCSH are expected for the Virgin Islands
terminals after 29/14Z and for TJPS after 29/17Z. Brief reduction
in VIS and low ceilings will be possible at times. Mountain
obscurations are expected across the Cordillera Central and
western Puerto Rico after 29/17Z. Winds will be out of the ESE at
10 to 14 knots, with stronger gusts.

&&

.MARINE...This morning the seas remain up to 5 feet. A small
northerly swell has arrived in the area but does not pose much of
a change to wave heights. Tonight winds will start to increase up
to 15 knots. Starting Wednesday, winds begin to increase to 20
knots creating choppy seas up to 8 feet. The combination of
another northerly swell and the increase of winds will likely
cause hazardous marine conditions.

There remains a moderate to high risk of rip currents across
northern Puerto Rico, Culebra, Vieques, and the U.S. Virgin
Islands that continues out to Wednesday night. The risk of rip
currents will increase as the marine conditions deteriorate over
the next few days.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 84 72 84 73 / 30 50 40 50
STT 83 70 83 73 / 20 50 30 40

[cycloneye]

Area Forecast Discussion...DELAYED
National Weather Service San Juan PR
619 AM AST Wed Mar 30 2022

.SYNOPSIS...As high pressure forms north of Puerto Rico tonight,
winds will increase bringing hazardous seas and the risk of rip
currents. Breezy conditions will increase the chance of advective
showers. A passing upper level trough on Thursday night
and Friday will enhance the shower activity in the area.

&&

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

Decreasing moisture levels are expected today; Total Precipitable
Water imagery from GOES-16 shows a drier airmass is making its
way into the area from the east. Satellite estimates suggest
precipitable water values of around 0.9 inches are associated with
this airmass, with these lower values currently east of the Virgin
Islands. Seasonal normals are on the order of 1.15 and 1.5 inches
There are some patches of moisture that can be seen embedded in this
airmass, however, which will help to support a few showers from time
to time. On the whole, however, generally fair weather is expected.
With winds expected to be around 15 to 20 mph, any showers that do
develop will move quickly, limiting rainfall totals.

Drier than normal conditions will continue through tomorrow and
Friday, as well. Though an upper-level trough approaching from the
west on Thursday, and passing over the area on Friday, will likely
modestly improve the dynamics, there will remain good stability in
the mid-levels. As such, generally fair weather, with isolated to
scattered showers, is expected through the end of the workweek.

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

In the upper levels, early in the weekend a ridge of high
pressure system will be situated north north northeast of Puerto
Rico in the central Atlantic and will maintain generally stable
conditions aloft.

At the surface high pressure builds over the western Atlantic and
will maintain moderate to fresh easterly tradewinds. This will
bring patchy moisture across the area in quickly passing showers.
Over the weekend the GFS20 precipitable water forecast shows air
masses with values of 0.65 to 1.2 inches moving through the area,
with winds values starting to decrease. This moisture will fuel
morning showers in the windward regions and afternoon showers in
the west with local effects playing a major role. GFS 1000-850 mb
thickness guidance indicated that temperatures will rise during
the weekend, possibly providing enhanced conditions for diurnal
convection and coupled with southeast flow, warmer temperatures
along the north northeast coasts of Puerto Rico. Otherwise
temperatures will remain pretty much near normal.

&&

.AVIATION...Generally VFR conditions are expected across all
terminals next 24 hours. VCSH until 30/14Z at TJSJ/TIST/TISX are
expected to have limited operational impacts. Winds will increase
after sunrise, generally out of the east to east northeast at 12
to 18 knots, with sea breeze variations. After sunset, winds
subside, becoming generally light overnight.

&&

.MARINE...With winds up to 15 knots from the east, seas will be up
to 6 feet tonight and then 7 feet in the morning. We expect
increasing wind speeds up to 20 knots from the east with
occasionally stronger gusts. Breezy conditions and a northerly
swell will result in choppy seas up to 7 feet requiring a small
craft advisory in the local outer Atlantic waters. Fresh breezes
will continue from Thursday into the weekend, maintaining
hazardous conditions until Friday night.


The high risk of rip currents will spread around the beaches of islands
with north and east exposures today through Friday.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 84 73 83 74 / 40 40 40 40
STT 83 73 82 73 / 30 30 30 20

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
525 AM AST Thu Mar 31 2022

.SYNOPSIS...

A seasonal pattern is expected to persist over the region.
Generally fair weather is expected for much of the islands, with
occasional showers affecting the area. Passing showers for eastern
sections of the region during the overnight and morning hours,
with showers in downwind areas of Puerto Rico during the
afternoons possible.

Small Craft Advisories are in effect for seas of up to 7 feet
starting today. There is a high risk of rip currents for most
local beaches.

&&

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

A cool advective pattern brought showers along the northern and
eastern sections of Puerto Rico throughout the overnight/early
morning hours. Maximum rainfall amounts between 0.30-0.50 inches
were observed from Toa Alta eastward to Rio Grande and Naguabo.
Breezy conditions were also observed across the islands, and a NOS-
NWLON station in San Juan reported a 34 mph wind gust just after 2
AM. Variably cloudy skies kept minimum temperatures in the low 60s
across the higher elevations, and in the low to mid 70s across
coastal areas. Due to the stronger than normal winds, showers made
it further inland and across most of central and western PR, and as
well across all the USVI.

For the rest of today, showers and cloudiness should clear off the
islands by mid-morning. Later in the afternoon, the proximity of an
upper level trough to our west should enhance diurnal convection
over western PR. However, limited moisture content and strong trade
winds should keep rainfall amounts at less than an inch over the
west coast. Across the USVI, streamers are expected to develop
downwind of the islands, but no significant rainfall amounts are
expected at this moment. Breezy conditions will continue through
Friday across the islands and regional waters. The upper level
trough should move over the northeastern Caribbean by Friday
afternoon, drier air intrusion and more stable conditions should
prevail in general. On Saturday, winds decrease and turn more from
the east to southeast. However, the best moisture content across the
region is expected to remain across the offshore Caribbean waters
during the day, and diurnal shallow convection will favor showers
over northwestern PR. A small surge in moisture is forecast later in
the evening hours, and scattered showers are possible across the
USVI and east/southern sections of PR through Saturday night.

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

On Sunday, surface high pressure located northeast of Puerto Rico
will support east-southeasterly winds and help to keep the
moisture associated with the remnants of a cold front away from
the region. Patchy moisture will stream across the region from
time to time, supporting shower activity. A large patch of
moisture is forecast to pass by the islands to the south early in
the day on Sunday, with precipitable water values that are near
seasonal normals. Elsewhere in the region, lower moisture amounts
are likely to be seen. Smaller patches of moisture are likely to
affect the region off and on through the week, which will help to
support a typical shower pattern across the region. As such,
passing showers are expected to develop over the waters during the
overnight and morning hours and push onshore from time to time. In
the afternoons, shower development is possible in northwestern
and interior portions of Puerto Rico, except around midweek, when
a shift in winds to become more easterly could bring more activity
to western and interior Puerto Rico instead.

A modest increase in instability is likely for around Tuesday into
Wednesday, as an upper-level trough passes by the region to the
north. Model guidance suggests some weak divergence aloft
supporting ventilation and convection. Even so, relatively dry air
above around 800 hPa and shear above 500 hPa is likely to inhibit
convective development over the islands. As such, an increase in
shower activity is likely, but strong convection is unlikely.

&&

.AVIATION...

Mainly VFR conditions are expected to prevail across all terminals
during the next 24 hours. However, early morning showers may
cause brief MVFR cigs at TJSJ and the USVI terminals. Then, SHRA
over western PR should cause tempo MVFR conds at TJBQ from 31/18z-
22z. Winds are expected to increase from the east at 15-20 kts
with higher gusts and sea breeze variations aft 31/14z.

&&

.MARINE...

Winds up to 20 knots are causing seas up to 7 feet this morning,
lasting through at least Friday. The nearshore buoy at San Juan
has been showing seas of around 4.5 to 5 feet through the last few
hours. Seas are forecast to continue to build under the influence
of the moderate to fresh winds, resulting in choppy and hazardous
conditions; these conditions will peak on Friday morning, with
gradual improvement during the day on Friday and into the weekend.
Combined with a weak northerly swell, confused seas are likely at
times. There is a Small Craft Advisory in effect starting this
morning for the offshore Atlantic waters, and this evening for
other portions of the local waters.

There is a high risk of rip currents for beaches of northern and
southeastern Puerto Rico, as well as for the beaches of the U.S.
Virgin Islands, Vieques, and Culebra.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 85 73 86 74 / 40 50 10 10
STT 85 72 84 74 / 50 50 20 20

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
457 AM AST Sat Apr 2 2022

.SYNOPSIS...A surge in low-level moisture from the east will
bring cloudiness and showers across the islands today. Drier
conditions are expected to return on Sunday into early next week.
However, seasonable weather conditions will prevail in general, as
light trade wind showers will continue to move at times across the
windward areas during the night, followed by shallow afternoon
convection over western PR each day. Ridge pattern aloft and at
the surface is expected to hold through the long term period.
However, a short wave trough and an induced surface trough are
expected to increase showers by midweek.


&&

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

Increased moisture is moving into the region from the east. Though
the areas of peak moisture are remaining south of the islands, there
is sufficient moisture to help support shower activity over the
region. That being said, moisture levels will remain well within
seasonally typical values; Total Precipitable Water imagery from
GOES-16 shows estimated PWAT values of around 1.3 to 1.35 inches
over the islands, and 1.4 to 1.5 inches over the local Caribbean
waters. Aloft, there is a ridge at the lower mid-levels, and the
troughing above that has decreasing influence over the area, as it
weakens and moves eastward. As such, there is decent stability aloft
to inhibit significant shower development. Shear is also expected to
increase in the midlevels, which will also decrease the potential
for strong showers.

A drier airmass is forecast to make its way into the area tonight.
Though there are some patches of moisture embedded in this airmass
that will float over the area from time to time, they are relatively
small and weak. Precipitable water values are forecast to fall to
below normal, ranging between 0.9 and 1.1 inches, except up to
around 1.25 inches or so in the strongest moisture patches. This
will combine with the increasing stability and shear aloft to
sustain conditions that are relatively unfavorable for shower
development. A few showers are still likely from time to time, but
shower activity will decrease in both quantity of showers and
strength.

A seasonally typical shower pattern will prevail over the region
today. For tomorrow and Monday, however, decreasing activity is
anticipated. Winds are also expected to gradually weaken through the
weekend, as well.

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

A mid-level ridge is forecast to gradually build from the west
during the long term period, and strengthen over the region during
the weekend. A short wave trough is expected to move mainly north
and east of the area by midweek, and cause a weak reflection at
the lower and mid-levels. Meanwhile at the surface, a high
pressure is expected to slowly build over the central Atlantic and
hold through the end of the long term period. Winds are forecast
to remain mainly from the east to southeast at 15-20 kt. In
general, moisture content is currently expected to peak on
Wednesday with precipitable water content increasing around 1.75
inches. This surge in moisture and better dynamics aloft should
result in modest convection during the day with periods of
moderate to locally heavy rainfall.

During the rest of the period, a similar weather pattern can be
expected, as patches of low-level moisture embedded in the trade
winds stream from time to time across the eastern Caribbean.
Therefore, fair weather conditions should prevail in general with
minor rainfall accumulations across the islands, with the
exception over west/northwest PR where moderate rainfall amounts
are possible due to locally induced afternoon showers.


&&

.AVIATION...Generally VFR conditions are expected next 24 hours
across all terminals. VCSH are expected to have limited
operational impacts TJSJ/TIST/TISX/TJPS through 02/14Z, with brief
MVFR poss TJSJ fm 02/08Z to 02/10Z. Winds pick up after sunrise,
generally out of the east to around 12 to 18 knots, with stronger
gusts and sea breeze variations. Winds decrease again after
sunset, becoming relatively light.


&&

.MARINE...Small crafts should continue to exercise caution across
most of the local waters through the rest of the weekend, due to
winds up to 20 knots and seas up to 6 feet. Across coastal areas,
there is a high risk of rip currents for beaches with a northern
and eastern exposure in Puerto Rico, including Vieques and Culebra,
as well as for the beaches of the U.S. Virgin Islands.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 86 74 88 75 / 30 20 10 30
STT 85 74 84 75 / 30 20 20 30

&&

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
519 AM AST Sun Apr 3 2022

.SYNOPSIS...A seasonable weather pattern is expected in general,
as light trade wind showers will continue to move at times across
the windward areas during the night, followed by shallow afternoon
convection over western PR each day. Ridge pattern aloft and at
the surface is expected to hold through the long term period.
However, a short wave trough and an induced surface trough are
expected to increase showers by midweek.


&&

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

An area of moisture remains over the region this morning. GOES-16
estimates of total precipitable water are around 1.4 to 1.5 inches,
which is within seasonal normals. Behind this, however, is a drier
airmass, which has already begun to move over the Virgin Islands.
Moisture values will fall below seasonal normals, with precipitable
water around 0.8 to 1.1 inches by later this morning for most of the
region. Aloft, stability persists, with ridging prevailing at the
mid- and upper-levels. Lingering showers are likely this morning,
followed by a drying trend. A fw showers are possible this afternoon,
as well. On the whole, though, generally fair weather is expected
across the islands today.

Patchy moisture will traverse the region from time to time; however,
these patches will likely only bring precipitable water values to
near the lower end of the range of seasonally typical values,
especially tomorrow; likely ranges are 1.1 to 1.3 inches or so on
Monday and 1.2 to 1.4 or so inches on Tuesday. This will inhibit
shower development. Even so, a few showers are likely, in a
typical pattern. Isolated passing showers during the overnight and
morning hours are anticipated, mostly over the waters, with a few
pushing onshore, and isolated to locally scattered showers are
possible during the afternoon, mostly in western/northwestern and
interior Puerto Rico.

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

A short wave trough and associated low-level perturbation are
expected to increase shower activity across the islands on
Wednesday. Thereafter, a mid-to-upper level ridge is forecast to
build over the region from the west and hold through the weekend.
This should promote more stable conditions once again, and limit
the vertical development of showers. At the surface, a building
high pressure over the central Atlantic should continue to promote
moderate to locally fresh ESE winds through the forecast cycle.
Moisture content is still expected to peak on Wednesday with
precipitable water content increasing to near 1.70 inches. This
surge in moisture and better dynamics aloft should result in
modest convection during the day with periods of moderate to
locally heavy rainfall, mainly over the eastern interior and
western PR in the afternoon.

During the rest of the long period, a seasonal weather pattern
can be expected under the influence of the upper level ridge.
Patches of low-level moisture embedded in the trade winds will stream
from time to time across the eastern Caribbean. Therefore, passing
showers with minor rainfall accumulations are expected across the
USVI and windward areas of PR during the night/early morning
hours...followed by diurnally induced afternoon showers over
west/northwest PR each day.


&&

.AVIATION...VFR conditions expected to prevail across all
terminals next 24 hours. Brief MVFR cannot be ruled out TJBQ
during afternoon, with VCSH expected between 03/17Z and 03/23Z.
Winds pick up after sunrise, to around 10 to 15 knots out of the
east, with sea breeze variations and stronger gusts at times.
After sunset, winds subside again, becoming light overnight.


&&

.MARINE...Choppy seas up to 6 feet and easterly winds between 15
and 20 knots are expected to continue today across the regional
waters. For the beach goers, there is a high risk of rip currents
for beaches with a northern and eastern exposure in Puerto Rico,
including Vieques and Culebra, as well as for the beaches of the
U.S. Virgin Islands.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 88 74 88 75 / 10 30 30 10
STT 84 74 84 76 / 20 30 30 30

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
442 AM AST Mon Apr 4 2022

.SYNOPSIS...

Mainly fair weather conditions with some shower activity
will prevail today through Tuesday, with a higher potential for
shower by midweek as an induced surface trough reaches the area.
Marine and surf zone conditions will continue to improve today,
with moderate risk of rip currents across most beaches of the
local islands.


&&

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

The U.S. Virgin Islands and Puerto Rico can expect a mixture of
sunshine and clouds today, with some showers affecting mainly the
surrounding waters of the USVI and the southern and eastern sections
of PR at times. In addition, the interaction across the Atlantic
Ocean between a surface high pressure and a cold front is inducing
an east-southeast wind flow, resulting in maximum temperatures
across the northern coast of Puerto Rico in the low 90s.

Although the lack of moisture and hostile atmospheric environment
should hinder widespread rains, an approaching short wave trough (at
mid to upper levels), a surge of low-level moisture combined with
local and diurnal effects will support the development of afternoon
to evening showers. This activity will affect the interior and
northwest PR, the San Juan Metro Area, and downwind from the Virgin
Islands. Periods of moderate to locally heavy rains could produce
ponding of water in roads and poorly drained areas.

The short wave trough will swing by on Tuesday. Still, the available
moisture will make rain formation tricky again, and with a
southeasterly wind-flow maximum temperature should reach the low
90s. The remnants of an old frontal boundary embedded in the trades
and forecast to reach the islands from the east by Wednesday will
increase the available moisture and the potential to observe showery
weather. Therefore, Wednesday seems to be the wettest day in the
short term period.

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

Thursday starts dry with an upper level ridge dominating the
forecast area. Precipitable water content is forecast to be at or
below 1.0 inches by early Thursday. However, a mid- to upper-level
short wave trough east of the region will persist through the
weekend. Although the ridge will be the predominant feature
promoting dry and stable weather conditions aloft, the short wave
trough will induce surface perturbations east of the Leeward
Islands. These induced surface perturbations/troughs will be
dragged by the easterly trades through Sunday. Therefore, shallow
moisture streaming across the area under a generally east
southeast wind flow will fluctuate between 1.0 to 1.4 inches,
putting values below normal to normal climatological levels. This
will cause alternating surges of cloudiness and shower activity as
these perturbations reach the area from the east with clear skies
and very few showers in between. Light to moderate rainfall
accumulations can be expected especially for the northwest quarter
of Puerto Rico each afternoon. By early next week, model guidance
suggests a gradual transitioning of the weather pattern to favor
unstable and wetter conditions. This is owed to a polar trough and
associated frontal boundary, exiting the eastern United States,
forecast to approach the forecast area. If this plays out, expect
an increase in convective development across the region. Stay
tuned to the latest forecast updates as this weather pattern
unfolds.

&&

.AVIATION...VFR conditions expected to prevail across all
terminals during the next 24 hours. Very brief MVFR cannot be
ruled out at TJBQ/JSJ during afternoon (between 04/17-23Z). Calm
to light/VRB winds will continue thru 04/13z, then should return
from the ESE at 10-17kt with sea breeze variations and stronger
gusts at times.


&&

.MARINE...Light to moderate easterly winds at 10-15 knots will
prevail through at least tonight, increasing tomorrow between
15-20 knots. Although marine conditions have improved, choppy
seas will return tomorrow across the regional waters, where small
craft operators should exercise caution. A low to moderate risk
of rip currents will prevail for all beaches across of the local
islands.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 88 74 87 75 / 30 30 30 60
STT 81 75 80 75 / 20 10 10 60

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
451 AM AST Tue Apr 5 2022

.SYNOPSIS...Seasonal weather conditions will prevail through the
cycle, with isolated to scattered shower activity favoring
eastern Puerto Rico and the U.S. Virgin Islands during the
overnight/early morning hours and central to western Puerto Rico
each afternoon. Wind-driven seas will maintain choppy marine
conditions for the next couple of days.

&&

.SHORT TERM...Tuesday through Thursday

Another day with below-normal moisture will limit rain activity
across the islands. However, the trade winds will bring patches of
moisture with clouds and showers across the local waters, the U.S.
Virgin Islands, and east and north Puerto Rico during the morning.
The surface high pressure will continue to promote an east-southeast
wind flow, resulting in maximum temperatures in the low 90s this
afternoon. An approaching short wave trough will induce a weakness
aloft, supporting a somewhat better instability. The lack of
moisture will hinder widespread activity, but afternoon convection
across the northwest quadrant of Puerto Rico could produce periods
of moderate to locally heavy rains. This quadrant should not rule
out ponding of water in roads and poorly drained areas with the
heaviest activity.

On Wednesday, the easterly winds will push the remnants of an old
frontal boundary across the islands, increasing the potential to
observe showery weather. Therefore, Wednesday seems to be the
wettest day in the short-term period. As the mid to upper-level
trough moves into the Central Atlantic, it will induce perturbations
in the trades winds that will reach the islands from time to time,
boosting the arrival of clouds and showers.

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

The mid-term forecast continues to be consistent with a seasonal
weather pattern. The mid- to upper-level low east of the Leeward
Islands will continue to move eastward on Friday through the
weekend while ridging aloft will promote dry and stable weather
conditions. At low-levels, the induced surface perturbations will
get pulled by the easterly trades towards the northeastern
Caribbean basin. Moisture content is expected to range below
normal to near normal levels across the forecast area. Although
dry and stable weather conditions will remain aloft, enough low-
level 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.

Global models have been backing off a little bit on the available
moisture expected by Monday through midweek of next week. That
said, they continue to suggest an increase in atmospheric
instability, especially by the end of the long-term period. The
models still indicate the presence of a polar trough exiting the
Eastern Seaboard with its associated frontal boundary approaching
from the northwest. The building trough and jet dynamics aloft will
increase instability at mid- to upper-levels with 500 mb
temperatures expected to drop to -9 degrees Celsius by Wednesday
of next week according to both GFS and ECMWF models. This should
elevate the potential for isolated thunderstorms. As it gets
closer to the CWA, the frontal boundary will get fragmented
looking, however, less pronounced than in previous model
solutions. Latest guidance also suggest the bulk of the frontal
boundary remaining mostly to the north of the local islands, over
the Atlantic waters. Therefore, the limiting factor is moisture
availability within the atmospheric column. To sum up, an increase
in the frequency and areal coverage of showers could play out as
environmental conditions gradually become more favorable for
shower development. Forecast confidence, however, continues to be
low for the latter part of the forecast period as frontal boundary
placement and moisture content variability continues between
model cycles.


&&

.AVIATION...VFR conditions expected to prevail across all terminals
during the next 24 hours. Brief MVFR cannot be ruled out at
TJBQ/JSJ during afternoon, especially between 05/17-22Z. Calm to
light/VRB winds will continue thru 05/13z, returning from ESE at
15-20kt with sea breeze variations and stronger gusts at times.


&&

.MARINE...Easterly winds up to 20 knots will continue on for the
next couple of days. This will sustain choppy seas up to 5 feet.
Even though wave heights have decreased compared to last week,
small craft operators should exercise caution across most of the
regional waters. Beach goers should be aware that there is a low
to moderate risk of rip currents for all beaches across the local
islands.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 87 75 87 75 / 10 60 60 30
STT 80 76 79 76 / 10 60 60 10

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
502 AM AST Wed Apr 6 2022

SYNOPSIS...Today, the easterly winds will push the remnants of an
old frontal boundary across the islands, creating variably to
mostly cloudy skies and rainy conditions across the area. Weather
will remain similar throughout the week, with some days more
favorable for precipitation due to higher moisture values.
Increasing instability next week due to an amplifying upper-level
trough will elevate the potential of shower and isolated
thunderstorm activity. Winds will cause seas to be choppy for the
next few days, therefore mariners should exercise caution.


&&

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

Today, the easterly winds will push the remnants of an old frontal
boundary across the islands, creating variably to mostly cloudy
skies and rainy conditions across the U.S. Virgin Islands and Puerto
Rico. At the same time, a perturbation aloft will increase somewhat
the instability promoting periods of moderate to heavy rain by late
this morning into the afternoon. Under these conditions, expect
ponding of water on roads and poorly drained areas. In addition, it
is likely to observe urban and small stream flooding across portions
of mainland Puerto Rico.

A mid to upper-level ridge will build over the northeast Caribbean
from early Thursday morning onward, while a trough amplifies over
the Atlantic Ocean (east of the NE-Caribbean). This trough will
induce surface perturbations across the Atlantic Ocean that will
reach the Archipelago of PR/USVI embedded in the trades Thursday and
Friday. The last one seems to be the wettest day between Thursday
and Friday.

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

This weekend, ridging at upper-levels will promote dry and stable
weather conditions hindering deep convective development for the
most part. However, the TUTT east of the Leeward Islands will
continue to induce surface perturbations within the easterly trades.
As these perturbations stream across the area, moisture convergence
will be enhanced with values oscillating well below normal to
near normal levels. This will promote alternating periods of clear
skies/fair weather conditions with cloudy skies combined with
shower activity. A frontal boundary approaching from the northwest
will induce an east southeast wind flow across the forecast area
through Sunday. Therefore, expect showers to develop across the
U.S. Virgin Islands and southeastern Puerto Rico during late
overnight to early morning hours, later shifting to interior and
northwestern Puerto Rico each afternoon. Ponding of water in roads
and poorly drained areas can be expected with each passing
perturbation.

The frontal boundary is being induced by a polar trough exiting
the eastern United States. Both GFS and ECMWF models continue to
be consistent in the development of these features with the polar
trough amplifying as it moves eastward towards the northeastern
Caribbean basin. Therefore, the mid to upper-levels will gradually
become more dynamically unstable as the week progresses with a
strong cut-off low developing at mid-levels at the end of the GFS
model cycle. At low-levels, the bulk of the frontal boundary
continues to stall north of Puerto Rico and U.S. Virgin Islands.
As it do so, the frontal boundary is expected to get fragmented
with its remnants lingering across the forecast area. Once again,
biggest uncertainty lies on moisture availability over the local
islands with latest model guidance suggesting surges of moisture
close to 2.0 inches at times. Given the gradual increase in
atmospheric instability, at minimum we could expect localized deep
convective activity especially when combined with sea breeze
convergence and local effects. Therefore, expect a gradual
increase in showers and isolated thunderstorms, mainly during the
afternoon hours. As the frontal boundary approaches, winds will
shift more out of east north east. Expect activity to concentrate
over interior and northern/northeastern portions of the local
islands evening through early morning hours, moving over interior
and southwestern portions of Puerto Rico in the afternoon. Minor
urban and small stream flooding as well as ponding of waters on
roadways and in poor drainage areas will remain possible in
isolated areas with the heaviest rains.


&&

.AVIATION...Cloudiness will increase across the local flying area today. Expect
passing -SHRA/SHRA with brief periods of +SHRA across the terminals
from time to time. The activity will spread across the Cordillera
Central and west PR by 06/15z onward. Winds will continue from the E-
ESE at 10 knots or less, increasing to 15-20 knots with gusts up to
30 knots after 06/13z; sea breeze variations will also develop.


&&

MARINE...No major changes in the marine forecast. Choppy seas up
to 5 feet will continue through most of the workweek. The winds
will be up to 20 knots from the east to east southeast. There is a
moderate risk of rip currents across most of the local beaches.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 87 75 87 75 / 60 20 50 60
STT 80 75 80 75 / 60 30 40 60

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
439 AM AST Fri Apr 8 2022

.SYNOPSIS...

A surge of moisture embedded in the trades will bring clouds and
showers across the islands today. These showers will produce
ponding of water in roads and poorly drained areas throughout the
day. A somewhat drier air mass will arrive through the weekend. An
unstable weather pattern is forecasted from Tuesday onwards.

&&

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

Satellite imagery shows a broad band of dense cloud coverage
currently over the U.S. Virgin Islands extending northward. PWAT
values range between 1.4 to 1.5 inches. This pulse of moisture is
being induced by an upper-level short wave trough with axis over the
Leeward Islands. The surface induced trough is expected to move
westward, dragged by the easterly trades, throughout the day.
Despite the proximity of the upper-level short wave trough, weather
conditions are mostly being affected by a mid- to upper-level ridge,
with axis over Hispaniola, promoting subsidence and dry air aloft as
observed by the 08/00z TJSJ sounding and GOES-16 Water Vapor
satellite imagery. Therefore, the surface perturbation throughout
the day will enhance shallow convective development at most. Cloudy
skies and shower activity has already being detected throughout the
night across the island of St. Thomas, Vieques, Culebra and eastern
municipalities of Puerto Rico. Expect this trend to continue through
the morning hours over these regions. These showers should produce
ponding of water in roads and poorly drained areas.

In the afternoon, this activity is forecast to affect interior and,
under the influence of an east southeast wind flow, west/northwest
Puerto Rico as it combines with diurnal heating and sea breeze
convergence. Breezy conditions will also aid in the formation of
streamers downwind of El Yunque into the southern sections of the
San Juan metropolitan area. Periods of moderate to locally heavy
rain will produce accumulations of up to 1.0 inches with slightly
higher amounts in localized areas, especially across northwestern
Puerto Rico. This could cause minor urban and small stream flooding
during the afternoon activity.

As the upper-level trough weakens and moves eastward, ridging aloft
will strengthen and engulf the Northeastern Caribbean through
Sunday. The limiting factor for Saturday through Sunday will be
moisture availability which, according to model guidance, is
expected to fluctuate below normal to near normal climatological
values with each weak induced perturbation. Sunday looks to be the
driest with precipitable water values dropping between 0.9 and 1.0
inches, which is near two standard deviations below normal for this
time of the year. Hence, expect mainly fair weather conditions with
shallow areas of moisture embedded in the easterly wind flow
reaching the islands from time to time. This will cause passing
showers across PR and the USVI through Sunday. Some rainfall
accumulations can be expected with these activity, but overall it
will remain on the light side.

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

A mid to upper-level ridge will gradually collapse as a trough
aloft approaches the islands from the Western Atlantic. This
trough will amplify across the Eastern Caribbean, promoting an
unstable weather pattern from Tuesday onwards, based on GFS/ECMWF
forecasts. A frontal boundary will accompany this upper-level
feature and should bring above-normal moisture content through
much of the period. Once again, Model guidances agree that
favorable environmental conditions could be present for the
formation of thunderstorms and organized convection next week,
especially Wednesday and Thursday. Historically this weather
pattern favors unsettled weather conditions with urban and small
stream flooding, thunderstorms, and flash flooding.

&&

.AVIATION...

VFR conditions expected across the area throughout the period.
However, VCSH through 08/14z possible for TAF sites TJSJ/TIST/TISX.
Then, sct SHRA possible across NW PR between 08/17z and 08/22z.
Winds will continue from the SE at 15 to 20 kts with sea breeze
variations after 08/14z through 08/22z.

&&

.MARINE...

Mariners can expect moderate to fresh easterly winds and seas
between 3 and 5 feet with occasional seas up to 6 feet. As a
result, small craft operators are urged to exercise caution. A
northwest swell could reach the local waters early next week.
Beachgoers, the moderate risk of rip currents will continue across
most local beaches.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 86 73 87 74 / 70 30 10 20
STT 84 73 83 75 / 50 20 10 20

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
450 AM AST Sat Apr 9 2022

.SYNOPSIS...A seasonal weather pattern will prevail today. Mainly
fair weather conditions are expected with some showers across the
island from time to time. Winds are expected to be from the ESE
today at 10-20 mph.This weather pattern will continue through
midweek, when an upper level trough will promote unstable weather
increasing the potential for thunderstorms, heavy rainfall and
flooding.


&&

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

Relatively benign weather is expected through the weekend and on
Monday. Near to below normal moisture is expected across the local
islands with a few patches of moisture over the Caribbean waters,
stable conditions aloft, and overall a seasonable weather pattern is
expected. The day with the highest moisture in the short term period
would be Sunday, and it will peak at near normal levels, and for a
short time during the day. Therefore, brief isolated to scattered
showers are forecast in the overnight and early morning hours across
the USVI and eastern PR as well as the local waters. In the
afternoon hours, showers are expected to develop across portions of
western Puerto Rico. Given the below normal moisture, the shower
activity in the afternoons is expected to be limited in coverage,
but isolated areas could receive up to a half an inch or so of
rain.

The local winds are expected to be from the ESE today at 10-20 mph,
to E-ENE at 10-15 mph by Monday. This is due to a couple of surface
high pressures in the Atlantic that will be dominating the local
wind flow, one of them is over the central Atlantic, which will
dominate through Sunday, then another SFC High will move into the
western Atlantic by Monday. The temperatures will also be near
normal through the short term, but Sunday may have a few degrees
above normal high temperature across the northern portions of PR.,
to E-ENE at 10-15 mph by Monday. This is due to a couple of
surface high pressures in the Atlantic that will be dominating the
local wind flow, one of them is over the central Atlantic, which
will dominate through Sunday, then another SFC High will move into
the western Atlantic by Monday. The temperatures will also be
near normal through the short term, but Sunday may have a few
degrees above normal high temperature across the northern portions
of PR.

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

The forecast continues on track. A mid to upper-level ridge is
expected to diminish as a trough approaches the islands from the
Western Atlantic. This trough is expected to amplify across the
region, promoting unstable weather for the local islands and it will
linger across the area for several days. This pattern will support
the development of showers with rainfall accumulations over Puerto
Rico and the U.S. Virgin Islands. A shift on the winds from the
north-northeast will noticeable, when the trough merge with a
frontal system located in the east coast of the U.S..

Latest model guidance continues to forecast the development of
organized convection, heavy rainfall and thunderstorms. Bands
associated with the trough and the frontal system will place over
the islands by Wednesday (moving into Thursday), enhancing
unstable conditions aloft and shower formation. This pattern will
linger through the end of the long period. Impacts to take in
consideration are: urban and small stream flooding, thunderstorms,
landslides flash flooding, ponding of water in low drainage
areas, and dangerous driving conditions.

&&

.AVIATION...VFR conditions expected across the local terminals
through the forecast period. However, brief VCSH through 09/14Z
possible for TAF sites TJSJ/TIST/TISX. Then, sct SHRA possible
across NW PR between 09/17Z and 09/22Z. Winds will be from the E-ESE
at 5-10 KT through 09/13Z, increasing gradually to 15 to 20 KT with
sea breeze variations thereafter.

&&

.MARINE...Choppy marine conditions will persist throughout the weekend.
Breezy east-southeast winds up to 20 knots will prevail for the next
couple of days. Small Craft should exercise caution across the local
waters and passages. For beachgoers, high risk of rip currents are
in effect for the eastern beaches of Culebra & Saint Croix, and a
moderate risk of rip currents will continue across most local
beaches.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 87 74 89 76 / 10 20 20 20
STT 83 75 85 74 / 10 20 20 10