Caribbean - Central America Weather

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
128 PM AST Tue Feb 7 2017

.SYNOPSIS...Broad high pressure ridge north of the region will maintain
moderate to strong trade wind flow across the region through Wednesday.
The high pressure ridge is to then lift north northeast across the north
central Atlantic during the latter part of the work week as a polar
trough and associated cold front enters and move across the west and
southwest Atlantic.

&&

.DISCUSSION...The dominant moderate to strong easterly winds will
continue to transport occasional fragments of shallow trade wind
moisture across the region through Wednesday. This will result in
periods of passing clouds and mainly light to moderate showers
across the coastal waters and parts of the islands from time to
time.

A low level easterly perturbation is expected to move across the
region Wednesday through Thursday. This will increase low level
moisture convergence across the region allowing a better chance
for isolated to scattered but enhanced shower activity on Thursday
afternoon.

Improving weather conditions by Friday as drier air and decreasing
moisture transport is expected as the local pressure gradient relaxes,
and high pressure ridge aloft builds across the region. This is in
response to the amplification of a polar rough and associated cold
front forecast to enter and move across the western Atlantic through
Friday. Recent model guidance suggests a weakly induced surface trough
is to set up across the region as the front will stall and slowly dissipate
north and west of the forecast area. Another ridge of high pressure
will then build across the southwest Atlantic in the wake of this frontal
boundary and bring an increasing east to northeast winds by Saturday
and into the early part of next week. With that said,expect improving
conditions decreasing moisture advection and cooler temperatures for
the weekend due to the gradually increasing northeast wind flow.

&&

.AVIATION...VFR conds expected for the local terminals. Easterly wind
of 15-20 knots and gusty with sea breeze variations expected through
07/23Z. VCSH for TJBQ and TJMZ is possible as afternoon convection
is expected across NW-PR. Winds decreasing slightly after 07/23Z but
continued easterly and ISOLD -SHRA through the area may cause brief
VCSH across the local terminals except TJMZ through the overnight
hours.

&&

.MARINE...Small craft advisory will continue in effect for most of
the local waters due to hazardous wind driven seas. The exception
is in the near shore waters of west and southern PR where small
craft operators should exercise caution.

There is a high risk of rip currents for northern PR and a few
spots in Culebra and the USVI.

&&

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

&&

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
603 AM AST Wed Feb 8 2017

.SYNOPSIS...High pressure across the central atlantic will
continue to move farther away from the local area. A cold front
will approach the local area during the weekend. Patches of low
level moisture will continue to affect the local region from time
to time.

&&

.DISCUSSION...Partly cloudy to clear skies prevailed across Puerto
Rico and the U.S. Virgin Islands overnight. Some light passing
showers were noted over the local waters. Local area will remain
under the influences of a high pressure system located across the
Central Atlantic. This high pressure is producing moderate to
fresh trade winds across the region. These winds will continue to
transport patches of low level moisture across the area today.

For next few days, a much drier air mass will encompass the local
region. Therefore, chances of showers will be minimal, except for
diurnal showers affecting the local islands from time to time.

&&

.AVIATION...A surge of moisture will bring periods of clouds and
showers across all TAF site at times. During the morning, SHRA
expected across TJSJ/TIST/TISX/TNCM/TKPK. This SHRA should be brief.
Then, TJSJ/TJBQ can expect SCT-BKN ceiling at FL025-FL050 btwn 08/15-
22z. Winds mainly from the east at 5 to 10 kt through 08/13Z, then
increasing at 15 to 20 mph with higher gusts in and near SHRA.

&&

.MARINE...Seas will gradually diminish through Thursday across
most coastal waters. Small Craft advisories will continue in
effect as seas near 7 feet and winds up to 20 knots are expected.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 87 75 87 74 / 30 20 20 10
STT 84 75 85 73 / 20 20 20 20

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
158 PM AST Wed Feb 8 2017

.SYNOPSIS...Surface high pressure across the Central Atlantic will
continue to slowly move east until it dissipates by Sunday and
another surface high pressure builds in the western Atlantic. This
will keep an ESE wind flow for the next few days with a gradual
change to ENE for the weekend. Patches of moisture will pass
through the next few days but shower activity is expected to be
low.

&&

.DISCUSSION...Little to no shower activity was observed today
across the local area and satellite imagery is showing some
cloudiness developing across the local islands. The NW quadrant of
PR may observe some rain but it is not expected to be much rain
either. For the next few days, drier air is expected to continue
with a few patches of moisture that will occasionally move in,
causing some isolated to locally scattered showers during the
overnight hours and in areas of sea breeze convergence in the
afternoons. Temperatures might be a bit on the warmer side..in the
mid to upper 80s...across the northern coastal municipalities of
PR for the rest of the week as the ESE wind prevails. Then
freshening back up for the weekend and early next week when the
remnants of a frontal boundary approaches the local area early
next week.

&&

.AVIATION...VFR conds durg prd. Sct-Bkn lyrs nr...FL025...FL060...
mstly CLR abv. Passing -SHRA/SHRA btw E PR and NRN LEEWARDS...Few
Tops nr FL150. Fm 08/16z-0822z...VCSH at TJSJ/TJBQ/TJMZ. SFC Wnd
from the E-SE at 12 to 20 kt with OCNL higher gusts and near SHRA.
Wnds fm E 15-20 kts blo FL100 BCMG fm SW-W.

&&

.MARINE...Seas are diminishing and are expected to continue
diminishing. Latest buoys indicate that the nearshore waters are
already below small craft advisory criteria, but the outer
Atlantic buoy still has seas of 8 feet, for that reason the small
craft advisory continues for the offshore Atlantic waters but no
longer in effect for the nearshore waters. Seas up to 6 feet
elsewhere.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 75 87 74 86 / 20 20 10 10
STT 75 85 73 85 / 20 20 20 20

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
430 AM AST Thu Feb 9 2017

.SYNOPSIS...Strong high pressure across the North Central Atlantic
will move east as a cold front moves across the western Atlantic
next couple of days. Another high pressure system will build
behind the front. Patches of low level moisture embedded in the
trade winds will continue to affect the local islands from time to
time.

&&

.DISCUSSION...Some light passing showers were seen across the
forecast area overnight. Some of these showers moved over the east
and southeast sections of Puerto Rico but were short lived. Local
area continue to be dominated by a high pressure system which is
located across the Central Atlantic. This high pressure will move
east next couple of days as a cold front exits the eastern U.S. by
Saturday.

This cold front will approach the local area by the end of the
weekend, but it is going to weaken as it moves closer to the area.
However, an increase in shower activity is expected mainly Monday
and Tuesday next week. In the meantime, patches of low level
moisture embedded in the trade winds will continue to affect the
local region from time to time.

&&

.AVIATION...Limited SHRA activity expected, however passing -SHRA
expected across TJSJ/TIST/TISX through the morning. TNCM/TKPK can
expect SCT-BKN ceiling at FL020-FL050 til at least 09/12z. Although
limited SHRA are expected btwn 09/18-23z, BKN ceiling at FL025-FL040
are possible at TJBQ/TJMZ. Winds mainly from the east at 5 to 10 kt
through 09/13Z, then increasing around 15 kt with higher gusts and
sea breeze variations.

&&

.MARINE...Buoy 41043 indicated seas are gradually subsiding across
the offshore Atlantic waters. Latest model guidance indicated seas
will diminish below small craft advisory criteria by late tonight.
Kept the Small Craft advisory for AMZ-710 through 10 pm AST
tonight. Elsewhere, Seas up to 6 feet and winds up to 20 knots
are expected. Small Craft should exercise caution across these
waters.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 88 74 87 75 / 20 20 20 20
STT 84 73 85 73 / 20 20 20 20

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
139 PM AST Thu Feb 9 2017

.SYNOPSIS... Mid to upper level ridge pattern will dominate the
forecast area today but will flatten Friday through the weekend
as a polar trough and associated cold front will enter and move
across the west Atlantic. A low level induced trough extends across
the northern Leewards while the surface high pressure across the
northeast Atlantic continues to slowly shift farther north of the
region in response to the cold front moving across the west Atlantic.

&&

.DISCUSSION...The weakly induced low level trough will linger
across the region the rest of today and bring fragments of shallow
low to mid level cloudiness across the forecast area. However a
broad area of dry and stable air will quickly filter in from the
east and spread across the region overnight through the upcoming
weekend.

The prevailing east to southeast winds will become more east to northeast
and gradually increase over the weekend, as the aforementioned mentioned
cold front dissipates north of the area and surface high pressure quickly
builds across the west and southwest Atlantic. This overall pattern
will limit convection if any, and provide mostly pleasant weather
conditions for the next several days. Shower activity if any should
be limited to parts of the west interior and north coast of Puerto
Rico as well as the northern USVI. Winds will gradually become
more northeasterly by Saturday resulting in a cool, dry and stable
air mass allowing for mostly clear and sunny skies for the upcoming
weekend except for few early morning passing showers along the
north coastal areas.

By early next week remnants of the dissipating cold front/shear line
should sink southwards across the region as high pressure builds north
of the area. This should allow for a slight increase in low level moisture
convergence on Monday through Tuesday which will support a better chance
for early morning and afternoon convection. Thereafter a drier air mass
is forecast once again and a return of the prevailing easterly wind
flow with passing low level clouds and showers from time to time.

&&

.AVIATION...VFR conds expected through the forecast period with
little to no SHRA activity over the local area. Possible VCSH at
TJBQ/TJMZ between 09/18Z and 09/22Z with increasing cloudiness. ESE
winds at 10-15 KT for the rest of today with sea breeze variations.
Winds decreasing after 09/23Z to 5-10 KT remaining easterly with
little to no SHRA activity around the local terminals overnight.

&&

.MARINE...Small Craft Advisory will continue in effect for the offshore
Atlantic waters due to wind driven seas up to 7 feet until later tonight.
Seas 3 to 6 feet can be expected elsewhere. Small craft operators should
exercise caution over most of the local waters except for the near shore
waters of west and southern PR. Seas are forecast to continue to diminish
through Friday, then increase on Saturday and during the weekend as
high pressure ridge will build north of the region and a northerly
swell will arrive across the local waters.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 74 87 75 84 / 20 20 20 20
STT 73 85 73 84 / 20 20 20 30

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
446 AM AST Fri Feb 10 2017

.SYNOPSIS...Strong high pressure across the southeastern U.S. will
move across the western Atlantic, pushing a cold front across the
local area at the end of the weekend. An increase in cloudiness
and showers are expected by then. High pressure will weaken
quickly as another cold front exits the eastern U.S coast by
Monday.

&&

.DISCUSSION...Clear skies prevailed across Puerto Rico and the
U.S. Virgin Islands overnight. No shower activity was observed
over most land areas. High pressure system will continue to
dominate the local region through at least Saturday night. A cold
front currently extending from the northeastern U.S, south toward
the northern Bahamas, will move rapidly southeastward during the
next couple of days. This cold front will approach the local area
Sunday night into Monday. An increase in cloudiness with showers
are then expected.

For early next week, the remnant of this front will linger across
the region through mid week.Therefore, some isolated to scattered
showers can be expected each day, beginning on Monday and
continuing through at least Wednesday.

&&

.AVIATION...VFR conds expected through the forecast period with
little to no SHRA activity over the local area. Possible VCSH at
TJMZ/TJPS btwn 10/18Z-22Z with SCT-BKN ceilings at FL025-FL050. Calm
to light and variable winds until 10/13z, becoming from the NE at
around 15 kt and with sea breeze variations.

&&

.MARINE...Seas up to 6 feet are expected to continue across the
offshore Atlantic waters through Saturday. Seas of 3 to 5 feet
can be expected elsewhere. Small craft operators should exercise
caution over the offshore Atlantic waters. Seas are expected to
increase on Saturday night and during the weekend as high
pressure ridge will build north of the region and a northerly
swell will arrive across the local waters.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 86 75 84 74 / 20 10 10 50
STT 85 73 84 73 / 20 10 20 30

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
203 PM AST Fri Feb 10 2017

.SYNOPSIS...A frontal boundary will cross through the area on
Monday bringing increasing clouds and shower chances area-wide
Sunday through late Tuesday. A warmer air mass will return
Wednesday through Thursday with no additional moisture.

At upper levels...The jet going over the ridge north of the area
last night will sink slowly south through the area Saturday night
as a trough approaches and then moves through on Sunday night. A
series of weak short waves will keep the trough close by until a
ridge moves over the area on Wednesday.

At mid levels...High pressure stretching east and west just north
of the area will continue through the weekend. High pressure will
retreat to the west as a weak trough deepens over the northeast
Caribbean Monday and moves into the tropical Atlantic on Tuesday.
Mid levels remain very dry except for moisture associated with
the frontal boundary Sunday night through Thursday. A shot of
moisture from the tropics is now being forecast to move into the
area the Saturday after next.

At lower levels...High pressure will move into the western
Atlantic ocean tonight pushing a front ahead of it. The front will
slow but finally cross through the area Sunday night with cooler
air and showers. The front will undergo considerable decay with
the moisture from the boundary remaining over the area through
mid-week next week.

&&

.DISCUSSION...The showers that crossed Saint Thomas and Culebra
are now just east of Fajardo and should dampen the eastern tip of
Puerto Rico before 3 PM AST. Showers have yet to form in southwest
Puerto Rico this afternoon, but are still possible. Amounts will
be light as showers move from the northeast. Showers may linger a
little after sunset over land today as a cold front approaches the
area and a pre-frontal boundary attempts to form over the area.
Although the moisture around the front is expected to increase,
models may be over-estimating the cloudiness both Saturday and
Sunday so have kept temperatures near persistence both days.
Currently the wettest day appears to be Monday with moisture and
clouds lingering through Wednesday. This is also the time period
that mid level moisture persists--beginning on Sunday night. Until
then mid levels beginning as low as 10 kft, are very dry and only
shallow convection will be able to form driven by surface
moisture and an adiabatic layer from 3500-6000 feet and capped by
a strong inversion.


&&

.AVIATION...Some MVFR CIGS are psbl at TNCM and TKPK in passing
SHRA otherwise VFR conditions will prevail through 12/02z. VCSH is
expected this afternoon at TJSJ, but TJMZ will likely remain VFR.
Brief mtn obscurations psbl in wrn PR til 11/02z and again aft
11/16z. sfc winds incrg aft 11/14z to bcm ENE at 10 to 18 kt.
Maximum winds by 11/18z btwn FL350-410 WSW to 90 kt.

&&

.MARINE...A northerly swell will invade the area Saturday night
and seas will become 7 feet in areas with exposure to the north
northwest. Most areas will subside to no more than 6 feet by
Monday morning. Outer Atlantic waters will take a little longer.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 75 85 74 84 / 10 10 50 50
STT 73 85 73 85 / 10 20 30 30

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
520 AM AST Sat Feb 11 2017

.SYNOPSIS...
Ridge is weakening aloft as an upper level trough amplifies over
the region. A high pressure on the West Atlantic will move
eastward pushing a frontal boundary near and into the region late
Saturday night into the upcoming week. As a result, cloudiness
will increase, as well as the chance of widespread showers Sunday
into the first part of the upcoming week.

&&

.DISCUSSION...
The northeast wind flow brought pleasant climatological
temperatures across the local islands. However, clouds and
showers slowly increased across the surrounding waters and some of
them moved inland over the windward sections overnight and early
this morning. The northeast wind flow will continue to push clouds
and showers mainly to the north of the Cordillera Central,
Culebra, and the U.S. Virgin Islands during the morning hours.
Then, afternoon convection is expected to develop over the
interior and southwest portion of Puerto Rico.

A migratory surface high pressure will continue to move eastward
across the Western Atlantic. This pressure system will push a
frontal boundary near and across the local Atlantic waters late
Saturday night into early next week. This feature will combine
with a mid-upper level trough to bring an increase in low level
moisture and local instability across the region.

Model guidance suggested the arrival of a dry air mass and the
return of an upper level ridge by the upcoming mid week. The
surface winds are forecast to become more from the southeast,
increasing the local temperatures through this period.

&&

.AVIATION...
VFR conditions are expected to prevail across all TAF sites
through the forecast period. Some passing showers are expected
over TNCM AND TKPK. VCSH are possible over TIST, TISX and TJSJ.
Low level winds will be mainly east northeast at around 15 kts
with higher gusts.

&&

.Marine...Seas of 3 to 6 feet expected across the region today.
However, seas will increase by late tonight, as a northerly swell
is expected to move from the north-northwest across the region.
Therefore, a small craft advisory is in effect across the Atlantic
waters and Caribbean passages late tonight into early next week.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 84 74 82 74 / 20 40 70 40
STT 85 72 83 73 / 20 20 50 40

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
159 PM AST Sat Feb 11 2017

.SYNOPSIS...A cold front will approach the local islands tonight
and pass through late Sunday bringing an increase in showers.
Warmer and somewhat drier conditions will appear Wednesday
through Friday.

At upper levels...An 85 to 90 knot jet from the west is crossing
over Puerto Rico and the U.S. Virgin Islands and will be followed
by a trough tonight. A short wave will pass through on Monday
night. Then beginning mid week high pressure will spread over the
area from southeast of the Windward Islands. This same ridge will
shift to the western Caribbean by the end of next weekend.

At mid levels...Weak northwesterly flow around a high over the
Gulf of Mexico will continue until mid week as a trough digs
weakly over the eastern Caribbean from the north. Later in the
week high pressure will build over the western tropical Atlantic
and ridge northeast. Mid levels will see some moisture from the
frontal passage which will linger in the area for much of the
week. Models are now indicating a second cold front passage on
Sunday of next week.

At lower levels...High pressure over the western Atlantic will
decay while sinking slowly south tonight through Tuesday. A cold
front will move through the area leaving some moisture through
much of the week. A weak ridge over the central Atlantic will
generate gentle to moderate southeast trade wind flow. A second
cold front passage is possible Sunday night on the 19th or the
next day.

&&

.DISCUSSION...A few showers during the midday period were seen
briefly on radar over the local waters and central Puerto Rico,
but showers are very light and most have dissipated as of 2 PM AST.
Showers are expected to increase overnight as the cold front, now
almost motionless over the Atlantic waters about 160 miles
northwest of San Juan or 180 miles northwest of Saint Thomas,
begins to move southward again. Chances for showers in the
northeast flow will increase tonight, tomorrow morning and finally
late Sunday when the front is expected to pass. Considerable
moisture will remain over the area Monday and it is possible that
the front could stall and dissipate close by. This moisture will
linger in weakening east northeast flow through Wednesday, but
shower activity will nevertheless decrease. Convection will not be
too strong and only modest rain amounts are expected. Focused
convection could pass over a particular area for an extended time
if the front stalls however, so the situation will bear
monitoring.

Winds at the surface pick up a southerly component beginning
Wednesday and this will boost temperatures on the north side of
Puerto Rico Thursday through Saturday.

Drier air will move into mid levels later next week. Another
front heads into the area Sunday night or Monday of the following
week, but sunny weather will be in store just before it arrives.

&&

.AVIATION...Mainly VFR conditions are expected to prevail across all
terminals through the forecast period. Light passing showers are
possible across the Atlantic waters and a few could reach the
northern terminals of PR and TIST during the overnight hours into
Sunday morning. Low level winds will continue northeast at 8-22
knots.

&&

.MARINE...Seas will begin to increase overnight with the arrival
of a northerly swell. This will support small craft advisories for
the Atlantic waters and passages tonight through at least Sunday
and a high risk of rip currents for Puerto Rico, Culebra and Saint
Thomas. Conditions will begin to improve Monday, but another
slightly weaker swell event is forecast Wednesday.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 74 83 72 83 / 20 70 70 40
STT 72 83 73 83 / 30 50 70 40

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
501 AM AST Sun Feb 12 2017

.SYNOPSIS...
A frontal boundary will continue to move closer to the islands.
The moisture associated with this boundary is expected to pool
over the region late this afternoon into at least Tuesday. At the
same time, an upper-level trough will swing by through mid
midweek. As a result, cloudiness will increase, as well as the
chance of scattered to widespread showers late this afternoon into
the first half of the week. Surface winds are forecast to shift
from the east-southeast and a ridge pattern aloft could return
after mid week. This weather pattern will result in warmer than
normal temperatures across the islands.

&&

.DISCUSSION...
The northeast wind flow brought a patch of moisture with clouds
and showers across the northern half portion of Puerto Rico and
the northern U.S. Virgin Islands overnight. This wind flow
supported pleasant climatological temperatures across the local
islands. Isolated showers embedded in the northeasterly winds are
expected to move through the islands this morning. High
resolution model are suggesting the development of afternoon
convection over the interior and southern portion of Puerto Rico.

A surface high pressure across the Western Atlantic will push the
frontal boundary into the region through Tuesday. This will
combined with a mid to upper level trough enhancing instability
across the region. The trough pattern was suggested by the 500 mb
temperatures and 200 mb heights (among other variables) which are
forecasting colder than normal temperatures and lower than normal
heights, respectively.

Model guidance suggested the return of an upper level ridge after
mid week. In addition, surface winds are forecast to shift from
the east-southeast around Thursday into the end of the week. As a
result, the combination of a stable air mass with a southerly
wind flow will result in limited shower activity with warmer than
normal temperatures. However, patches of low level moisture are
expected at times each day.

&&

.AVIATION...
Mainly VFR conditions are expected across the forecast area
through 12/12Z. Increasing cloudiness with SHRA are expected at
TJBQ and TJSJ from around 12/12z producing brief periods of MVFR
conditions. Brief periods of MVFR conditions can be expected
elsewhere after 12/18Z as frontal boundary moves through the area.
Low level winds will be mainly from the east northeast at 10 to
15 kts with higher gusts in showers.

&&

.MARINE...
A northerly swell is propagating across the Western Atlantic.
A high surf advisory was issued due to breaking waves between 10
and 14 feet along the north facing beaches of Puerto Rico. Marine
conditions are deteriorating across the local Atlantic waters and
Caribbean Passages as a swell produces seas between 7 and 10 feet
with occasional seas up to 11 feet.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 84 74 82 72 / 30 50 50 20
STT 83 72 82 72 / 30 50 50 20

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
206 PM AST Sun Feb 12 2017

.SYNOPSIS...Showers from a passing cold front will move across the
area from northeast to southwest tonight and Monday. Some moisture
and showers will linger for the rest of the week. Prevailing flow
across the islands is east northeast, but will be southeast
Wednesday through Friday resulting in warming on the north coastal
areas of Puerto Rico.

At upper levels...A short wave set to pass Monday night will hold
the upper level jet south of the area until Tuesday. A ridge will
pass over the area on Wednesday and remain over the eastern
Caribbean through the end of the week.

At mid levels...Weak low pressure will continue over the eastern
Caribbean until mid-week. High pressure then builds over the
Leeward Islands and spreads west over the Greater Antilles through
the weekend. Modest mid levels moisture will be present tonight
through Monday night and then return late in the week.

At lower levels...High pressure will slide east to the north of
the area while weakening through Tuesday night. Another high
pressure will form over the western Atlantic and build into the
central Atlantic through the rest of the week causing flow to
become temporarily southeast over the local area.


&&

.DISCUSSION...A cold front was just entering the northwest corner
of the forecast area this afternoon and is expected to continue
toward the islands overnight. Scattered showers have been seen along
the front and isolated showers have moved across the land areas
although some weakening occurred on approach. Showers were also
just beginning to form over the interior 8 to 10 miles inland.
This trend is expected to continue and increase until several
hours after sunset. At this time most models agree that showers
formation will end over interior Puerto Rico several hours after
sunset and continue over the upwind local waters and smaller
islands overnight. Rain will not be heavy in any event as the
front is weak and trying to dissipate.

Drier air behind the front will reduce but not entirely eliminate
shower activity after 14/00Z, and overall moisture will generally
decrease through Friday afternoon. A second frontal passage is no
longer obvious in the GFS next weekend, but the shot of moisture
accompanying southeast flow out of the southwestern tropical
Atlantic will not be able to reach this far north either. This
will leave isolated to scattered shallow showers for the remainder
of the forecast period.

&&

.AVIATION...Tempo MVFR conds possible at TJMZ/TJPS through 12/22z as
SHRA is developing over the SW quadrant of the island. Elsewhere,
mainly VFR will prevail. A front is weakening along 19N and some
clouds and showers are moving south into the local Atlantic waters.
Under ENE steering wind flow of around 10 kts some of this activity
could reach the northern PR and USVI terminals through the overnight
hours. Overnight winds at the sfc light and variable. Increasing
around 10 kts from the E-ENE after 13/13z with sea breeze
variations.

&&

.MARINE...Seas have peaked at both the inner and outer buoys and
are expected to subside very slowly through Wednesday. Small
craft advisory conditions are expected to return to the Atlantic
waters and passages then.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 74 82 72 82 / 50 50 20 40
STT 72 82 72 83 / 40 40 20 40

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
208 PM AST Mon Feb 13 2017

.SYNOPSIS...Trof aloft will continue mainly to the east of the
forecast area. Mid to upper ridge will build during the next few
days and dominate the Caribbean basin. At the surface weak front
is dissipating as strong surface high pressure builds across the
Western Atlantic and moves into the Central Atlantic by the end of
the week. Another weak surface front and polar trof are forecast
to move near the islands during the weekend.

&&

.DISCUSSION...Sunny to partly cloudy skies prevailed during the
day across the islands. Showers developed early in the afternoon
hours across the western sections of PR and over El Yunque area.
Additional cloudiness and shower activity are forecast to develop
along the mountain ranges of PR leaving between 1-2 inches of rain
with the heaviest showers. As steering winds are light, some
higher amounts could be possible in some isolated areas.

An overall drier weather pattern is expected for the rest of the
work week as mid level ridge dominates the local weather pattern
as it strengthens the cap inversion. However, diurnally induced
afternoon showers cant be ruled out each day over the interior and
western sections of PR. On Wednesday as the surface high moves
into the Central Atlantic, winds will shift from the southeast
bringing warmer than normal temperatures across the islands.
Otherwise, limited trade wind shower activity will prevail over
the waters with some reaching portions of the islands at time but
without any significant rainfall amounts.

&&

.AVIATION...All stations have remained VFR and MVFR conds are only
possible at TJMZ in SHRA btwn 13/18-21Z. SHRA have appeared between
TJMZ and TJBQ and will persist until btwn 13/21-24Z. Some mtn
obscurations are likely till 14/00z. VFR will prevail thru 14/18Z at
all stations. Sfc winds less than 10 kt with sea breeze influences,
bcmg less than 10 kt with land breezes aft 14/22Z. Maximum winds
west 85 kt arnd 14/06z at FL400.

&&

.MARINE...Seas are expected to remain below 6 feet for the next
few days. Another northerly swell is forecast to reach the local
Atlantic waters and Passages by Wednesday afternoon and small
craft advisories could be required by then. A high rip current
risk remains in effect through early this evening across the
Atlantic coastline of PR, Culebra and St. Thomas. Moderate risk
will persist across the northern beaches of the islands until
Wednesday when its expected to be high.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 74 84 74 86 / 30 30 30 30
STT 73 83 73 84 / 30 30 30 30

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
445 AM AST Tue Feb 14 2017

.SYNOPSIS...As trofiness aloft moves away today, a weak mid to
upper level ridge will build across the forecast area and hold
through early next week. This will result in a seasonable weather
pattern during the next several days with warm temperatures likely
across the northern slopes of Puerto Rico Wed and Thu.

&&

.DISCUSSION...Mostly clear to partly cloudy skies with brief shower
activity was observed overnight and early this morning across the
local islands. The overnight minimum temperatures were generally in
the low to mid 70s across the lower elevations and in the mid to
upper 60s across the higher elevations. The wind was light from the
north northeast.

A generally fair weather pattern is expected to prevail across the
local islands during the next few days. However showers embedded in
the trades may reach the coastal areas at times to result in passing
showers. Although ridge aloft will prevail Wed through early next
week; locally induced afternoon showers cant be ruled out due to
sea breeze convergence each afternoon. Unseasonable temperatures
are likely across the northern slopes of Puerto Rico Wed-Thu as a
building surface high north of the area moves into the central
Atlantic by mid week. There is a surface front which is expected
to dissipate north or the area the upcoming weekend.

&&

.AVIATION...VFR conds expected across the local terminals with SCT
-SHRA causing VCSH across TIST, TISX, TJSJ in the morning hours.
Light winds early in the morning but increasing to about 10KT and
turning N to NE for TJBQ, TJSJ, TIST after 14/14Z while sea breeze
variations will affect TJPS and TJMZ. TIST, TNCM and TKPK will have
East to ENE winds. SCT to locally NMRS SHRA in the afternoon may
affect the vicinity of TJPS and TJMZ after 14/16Z.

&&

.MARINE...Seas are expected to remain below 5 feet today. Another
northerly swell is forecast to reach the local Atlantic waters
and Passages by Wednesday afternoon. A moderate risk of rip
currents continues along the Atlantic shorelines today.

&&

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

&&

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
143 PM AST Tue Feb 14 2017

.SYNOPSIS...Drier air will prevail with near normal to
considerably below normal moisture for the next 10 days.
Scattered showers are possible in the west mainly when frontal
bands approach over the weekend and mid week next week. Otherwise
only a few showers will be seen in the forecast area. Warmer
temperatures are expected Wednesday through Saturday with little
cooling thereafter.

At upper levels...A weak trough passed through the area this
afternoon. As it moves east high pressure from the southwestern
tropical Atlantic will build over the area. That ridge will shift
into the western Caribbean next weekend. A trough will dig over
the area around Tuesday of next week.

At mid levels...High pressure will build progressively over the
Caribbean during the week and remain through the weekend. A trough
in the western Atlantic will pass through the area on Tuesday next
week. Mid level moisture will hover to the west for a few days
but otherwise it will be quite dry, except for only very limited
moisture during frontal passages mentioned below.

At lower levels...High pressure will build over the north central
Atlantic tonight through Friday maintaining a ridge to our north
and causing low level flow to become more southeast. High pressure
will build over the western Atlantic Saturday and Sunday causing
flow to return to the east northeast. Weak cold fronts will pass
through Saturday and the following Wednesday with only a minimum
of moisture for showers.

&&

.DISCUSSION...What is left of the old frontal boundary appears to
be south of Saint Croix and just west of the Mona channel where it
may be hung up on the island of Hispaniola. Showers have nearly
dissipated to the south and have so far have failed to generate
over the islands this afternoon.

Flow at lower levels is expected to turn to the southeast while
ridging takes over at mid and upper levels. Temperatures are
expected to rise a few degrees above the normal levels now being
experienced and the GFS confirms with generally higher 1000-850 mb
thickness levels Wednesday through Saturday. Thicknesses diminish
only slightly with two frontal passages, one on Saturday and one
expected on Tuesday. Only a minor amount of moisture will
accompany these fronts so the only rainfall of consequence will
have to come from local effects over Puerto Rico and stray showers
generated from the shallow moist marine layer now through the next
7 to 10 days.

&&

.AVIATION...Mainly VFR conditions expected across most of the local
flying area during the forecast period. SCT SHRA may affect the
vicinity of TJMZ from 14/19Z to 14/22Z. Only VCSH expected
elsewhere across the local TAF sites. Latest TJSJ sounding
indicated a light northerly wind flow from the SFC to around 15k
feet, becoming northwesterly and stronger aloft.

&&

.MARINE...A northerly swell is expected later Wednesday night and
this should bring seas up to 7 feet. This event is not expected to
last very long so seas should return to less than 7 feet
everywhere after Thursday night. Caribbean waters will not
generally be affected by this event.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 73 86 73 86 / 0 20 10 20
STT 71 84 73 84 / 0 20 10 20

&&

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
518 AM AST Wed Feb 15 2017

.SYNOPSIS...Light east to southeasterly winds are expected to
prevail over the next few days. Relatively dry air will prevail
over the next few days as well. Mainly fair weather expected and
any showers that may affect the local islands should be limited
to brief isolated to scattered brief showers in the overnight
hours over the windward side of PR and over the USVI, then
afternoon shower development possible due to local effects and
diurnal heating over PR. Marine and surf zone conditions to become
hazardous today and Thursday.

&&

.DISCUSSION...A weak SFC high pressure will pass to the north of
the local islands before being absorbed by a larger high pressure
across the eastern Atlantic and then slowly will move to the NE
while a SFC low pressure across the NE-US continues to move NE,
causing a SFC trough to the NW of the local area and in turn
causing a COL over the local area which will then keep the local
islands observing rather light ESE to SE winds through the end of
the workweek. A SFC high pressure will move to the north of the
local islands, bringing back easterly wind flow for the weekend.
Broad high pressure in the upper levels is also expected to
dominate through the end of the week. A broad upper trough is
forecast to move over the area early next week.

The current pattern setup will cause mainly fair weather to
continue through the end of the week. The limited available
moisture that is expected for the next several days will cause
mainly isolated to scattered showers in the overnight and early
morning hours across the local waters, the USVI and the windward
side of PR. But those showers are not expected to cause much
rainfall accumulations. Having said that, the local effects in PR
in combination with the diurnal heating will help develop showers
in the afternoon, especially in the areas of sea breeze
convergence, some of these showers could be significant in terms
of accumulation as it would not be surprising to see some of the
showers produce up to an inch of rain or so across isolated areas,
which could cause some ponding of water in poor drainage areas,
but generally speaking the showers that do develop should produce
a quarter inch of rain or less. For today, given the expected wind
flow and the sea breeze convergence location, the area with the
most expected rainfall is the NW quadrant of PR, similar thing for
Thursday as the general wind flow is not expected to change too
much, showers may make it a bit more towards the interior of PR on
Thursday than today.

&&

.AVIATION...VFR conds are expected to prevail through the forecast
period at all TAF sites with brief MVFR conds possible in and around
JBQ due to SHRA aft 15/17z. Light winds will continue early this
morning but becoming east southeast at around 10 knots aft 15/15z.


&&

.MARINE...There is a high risk of rip currents today for the
northeast to the northwest coasts of PR as well as some beaches in
Culebra. SW PR will have moderate risk of rip currents early but
will have a high risk of rip currents in the afternoon. Saint
thomas will have a high risk of rip currents across the
northwestern beaches today, worsening surf zone conditions
tonight. Northerly swell will cause local seas to deteriorate
starting tonight with seas rising up to 8 feet. A small craft
advisory will go into effect tonight at 8 PM AST.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 85 73 86 72 / 20 10 20 20
STT 83 73 82 71 / 20 10 20 20

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
203 PM AST Wed Feb 15 2017

.SYNOPSIS...Upper level ridge will continue to dominates the local
area through the weekend. A very week frontal boundary will stay
north of the local while weakening. Very dry weather conditions
will continue to affect the local region next several days.

&&

.DISCUSSION...Once again, a very dry air prevailed across Puerto
Rico and the U.S. Virgin Islands this afternoon. Very little
shower activity was observed across the local islands. Local area
will continue to be dominated by a upper level ridge which will
promote very dry weather conditions across the local area through
the rest of the week and beyond.

A very weak frontal boundary will continue to move slowly
southeast across the western Atlantic. This front will stay north
of the area while weakening. It is not until early next week,
another frontal boundary will it is expected to approach the
local region, increasing somewhat the chances for showers across
the region.

&&

.AVIATION...Mostly VFR conditions are expected to prevail through the
forecast period across the local flying area. Due to east southeast
low level wind flow, MVFR conditions are possible in and around TJBQ
due to SHRA until 15/22Z. Latest TJSJ sounding indicated a light
wind flow all the way from the surface to around 12K feet, becoming
northwesterly and stronger aloft.

&&

.MARINE...Buoy 41043 was showing seas increasing up to 9 feet as a
northerly swell invade the local waters. No changes were made to
marine forecast grids.

.FIRE WEATHER...Doppler radar detected a fire near Salinas and
Guayama around 1 pm AST this afternoon. As a very dry airmass will
continue across the region, Fire Danger will continue to increase
next few days. Fire and emergency officials should be aware that
weather conditions are becoming more conducive for the ignition
and spread of wild fires.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 73 86 72 85 / 10 10 10 20
STT 73 82 71 83 / 10 10 20 20

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
430 AM AST Thu Feb 16 2017

.SYNOPSIS...Light southeasterly winds are expected to prevail
today and Friday. Relatively dry air will prevail through the
weekend. Mainly fair weather expected and any showers that may
affect the local islands should be limited to brief isolated to
scattered brief showers in the overnight hours over the windward
side of PR and over the USVI, then afternoon shower development
possible due to local effects and diurnal heating over PR. Marine
and surf zone conditions to remain hazardous today.

&&

.DISCUSSION...The big story continues to be the local marine
conditions as the northerly swell will continue to cause
hazardous seas and surf zone conditions which includes high
breaking waves and a high risk of rip currents. When it comes to
the local weather, generally fair weather is expected with
possible showers developing across areas of sea breeze convergence
in the afternoon, which is expected today across the central and
western interior as well as some areas of north central PR. Some
of these showers could be moderate to briefly heavy but generally
speaking, the showers that do develop today are not expected to
cause anything more than some ponding of water on roadways and
poor drainage areas. The rest of the local area should remain dry
with only a slight chance of showers. Brief isolated showers are
still expected during the overnight hours for the next few days,
mainly affecting the local waters, USVI, and eastern PR.

A SFC high pressure across the northeastern Atlantic is slowly
moving to the NE while a SFC low pressure across the NE-US
continues to move NE. This will cause a SFC trough to move into the
NW of the local area and in turn cause a COL over the local area
by Friday, which will keep the local islands observing rather
light SE winds through the end of the workweek. A SFC high
pressure will move to the north of the local islands this weekend,
bringing back easterly wind flow. Broad high pressure in the
upper levels is still expected to dominate through the end of the
week. A broad upper trough is forecast to move over the area
early next week. The result of this may be increased shower
activity but at this time it looks like the increase in shower
activity will be for the leeward islands and not to have a
significant effect on the local islands. This is a few days out in
the forecast so the confidence is moderately low, although models
have been consistent.

&&

.AVIATION...VFR conds are expected to prevail through the forecast
period at all TAF sites with brief MVFR conds possible in and around
JBQ/JMZ due to SHRA aft 16/17z. East southeast winds around 10 knots
with some sea breeze variations aft 16/15z.

&&

.MARINE...The long period northerly swell will continue to
affect the local waters today. Seas between 6 and 10 feet are
expected across the Atlantic waters and Caribbean passages, which
are currently being confirmed by the local buoys. Elsewhere, small
craft operators are urged to exercise caution due to seas up to 6
feet. Dangerous breaking wave heights will create minor coastal
erosion and hazardous rip currents across some beaches of Puerto
Rico, Culebra and Northern U.S. Virgin Islands. Marine conditions
are expected to slowly improve after Tonight. There are high surf
and small craft advisories in effect, there is also a high risk of
rip currents.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 85 72 85 72 / 20 10 10 20
STT 83 72 84 72 / 20 20 20 20

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
202 PM AST Thu Feb 16 2017

.SYNOPSIS...Mostly dry weather will prevail through the weekend
although weak cold fronts will pass by on Sunday and Tuesday.
Moisture will gradually increase through mid week next week and
showers will increase slightly from the minimum seen, but
precipitable water will still not exceed 1.4 inches until Friday
of next week.

At upper levels...High pressure dominates the eastern Caribbean
and will shift west over the weekend as an upper level trough
slides through on Monday. A weak ridge finally makes it to the
area by Friday amidst northwest flow.

At mid levels...High pressure dominates the Caribbean until a long
wave trough passes through the area on Monday night. High pressure
rebuilds over the Caribbean thereafter. Mid levels see little
moisture during the period.

At lower levels...A ridge extends out of the northeast Atlantic
across the waters just north of Puerto Rico and the U.S. Virgin
Islands and will be reinforced by a high entering the western
Atlantic on Friday. This will cause the trade wind flow to gain a
slight northerly component over the weekend and allow the north
coast to return to near normal temperatures. Flow will become
lighter and more southeasterly until a cold front heads through on
Tuesday ahead of high pressure sinking south in the western
Atlantic.

&&

.DISCUSSION...Few showers appeared over the local waters and none
have formed over Puerto Rico or the U.S. Virgin Islands this
afternoon as of 2 PM AST. Weak convection is still expected over
northwest Puerto Rico later this afternoon with minimal
accumulations.

Weak boundaries are forecast to form and pass through the area.
The first, a pre-frontal trough to pass around Friday night. The
cold front to follow on Sunday. Then on Tuesday another cold
front is expected to pass. This latter cold front will actually
bring slight cooling to the area, but moisture remains sparse and
showers will be limited. Moisture gradually increases later next
week along with a noticeable increase in 1000-850 mb thickness.


&&

.AVIATION...Mostly VFR conditions are expected to prevail through the
forecast period across the local flying area with only VCSH possible
in and around TJBQ and TJMZ until 16/22z. Latest TJSJ sounding
indicated a light southeast wind flow all the way from the surface
to around 14K feet, becoming westerly and stronger aloft.

&&

.MARINE...Northerly swell has held seas around Rincon around 7
feet most of the day and just a little below that at the inner
buoy 41053. Therefore the Small Craft Advisory was extended until
8 pm AST in all areas where it was in place. Seas are still
forecast to subside and should do so sufficiently to drop the
advisory tonight, but this will have to be monitored closely. SCAs
are not expected to return during the next 7 days.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 73 86 73 84 / 10 10 0 0
STT 72 83 74 83 / 20 20 0 10

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
448 AM AST Fri Feb 17 2017

.SYNOPSIS...Sub-equatorial ridge will continue to dominate the
local weather. Under the influence of this mid-upper level
ridge...fair weather conditions will prevail over the next few
days. Pattern will change between Sunday and Monday as an upper
level trough amplify across the Western Atlantic. Increasing
clouds and shower activity is anticipated early next week.

&&

.DISCUSSION...Satellite derived precipitable water analysis shows
a dry air mass around 30%-40% below normal upstream of the U.S.
Virgin Islands. This drier and stable air mass will limit the
shower activity across the Northeast Caribbean Islands today.
High pressure over the Eastern Atlantic and frontal boundary over
the Bahamas is inducing gentle east-southeast flow across the
local region today. This will lead to another warm day along the
coastal sections of PR/USVI with maximum temperatures around 86-88
degrees...2-4 degrees above normal for this time of the year.

The ridge aloft will help to maintain the fair weather pattern
through Sunday Morning. A weak surface high pressure will move
over the Western Atlantic during the weekend...inducing a northeast
flow. With the northeast component...temperatures are forecast to
remain near or below normal through midweek next week. Moisture
will pool again over the islands on Sunday as surface high pressure
brings patches of moisture associated with the remnants of the
boundary over the islands. In addition...upper trough will swing
across the Northeast Caribbean...increasing the convective instability.
As a result...additional clouds and showers can be expected Sunday
through Tuesday. Dry air will return to the local islands by midweek...
leading to tranquil weather conditions.

&&

.AVIATION...Mainly VFR conditions will prevail across all terminals
through the forecast period. Isolated to scattered showers possible
in the afternoon across the southwest quadrant of PR. This could
result in VCSH at JMZ/JPS. Low level wind ESE at 10 kts or less. Sea
breeze variations after 14z.

&&

.MARINE...Northerly swell continues to fade out across the local
waters today. Offshore and nearshore buoys have indicated seas of
3-4 feet across the region. Seas will increase to 3-5 feet on
Sunday as another small swell reaches the local Atlantic Waters.
No small craft advisories are anticipated over the next 5 days.
Gentle winds will prevail today, increasing somewhat as shift from
the northeast during the weekend.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 86 73 84 73 / 10 0 0 20
STT 83 71 83 73 / 20 0 10 20

&&

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
115 PM AST Fri Feb 17 2017

.SYNOPSIS...An upper level ridge will continue as the main weather
feature across the region local islands for the next several
days. This feature will maintain a generally fair and stable
weather pattern across the local islands during the upcoming
weekend. An upper level trough is expected to amplify over the
region early next week, inducing and increase in cloudiness and
showers across the local islands.

&&

.DISCUSSION...Mostly sunny skies were observed across the local
islands this afternoon. Doppler weather radar detected only few
isolated showers were detected over the coastal waters, but not
significant precipitation was observed over land areas so far this
afternoon. The limited moisture across the region in combination
with daytime heating and local effects is possible to induce some
showers across western and interior sections of Puerto Rico late
this afternoon and this evening. The GFS model guidance suggests
that PWAT values will remain near 1.00 inch during the next few
days. These values do not support the development of any
significant shower activity over the region for the next few days.

A surface high pressure will move over the southwestern Atlantic
tonight and Saturday inducing a northeast low level wind flow
across the northeast Caribbean and pushing a weak frontal
boundary across the local Atlantic coastal waters late in the
weekend and early next week. An upper level trough is also expected
to amplify over the region early next week, inducing and increase
in cloudiness and showers across the local islands. Dry air will
return to the region by midweek.

&&

.AVIATION...Mainly VFR conditions will prevail across all terminals
through the forecast period. Isolated showers still possible late
this afternoon across the interior and western sections of PR.
This could result in VCSH at TJMZ. Low level wind ESE at 10 kts
or less.

&&

.MARINE...Offshore and nearshore buoys indicated seas of 3-4 feet
across the region. Seas will increase to 3-5 feet on Sunday as
another small swell reaches the local Atlantic Waters. No small
craft advisories are anticipated over the next 5 days. Gentle
winds will prevail today, increasing somewhat as shift from the
northeast during the weekend.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 73 84 72 85 / 0 0 10 10
STT 71 84 73 83 / 0 10 10 10