Caribbean - Central America Weather

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
201 PM AST Tue Dec 20 2016

.SYNOPSIS...Drier air filtering in from the east into the local
area. Mid level low is over the local area and will persist for
the next couple of days while the upper level trough will flatten
by Thursday. Strong surface high pressure over the eastern
Atlantic will keep easterly winds over the local area. Brief
showers are expected every morning and night over the local
waters, USVI, and eastern and northern PR.

&&

.DISCUSSION...Brief showers have affected portions of Puerto Rico
and the USVI today. Some of the showers were moderate and it
caused some flooding in some sectors since persistent showers were
observed overnight through those areas as well, particularly the
San Juan Metro and nearby municipalities. There were also some
showers across SW-PR in the early afternoon hours. It was also
breezy with winds at around 10-15 mph with gusts of up to about 25
mph across the coastal municipalities.

As the drier air filters in late today and tonight, the shower
activity is expected to gradually diminish, however it will remain
breezy and isolated brief showers are still expected. Moisture
will once again increase on Wednesday and Thursday. Given that the
overall pattern is not expected to change too much on Wednesday,
the shower activity is expected to increase to scattered to
numerous showers across eastern PR in the morning hours, same
thing for Thursday morning. Now as the upper trough flattens on
Thursday, the dynamics for thunderstorms are even less favorable
than it is for the next couple of days, however the overall
moisture is expected to increase significantly with precipitable
water values forecast at about 1.8 - 1.9 inches for this weekend.
Which will likely cause brief but constant off and on showers
across the local waters, USVI, and eastern and northern PR.

&&

.AVIATION...VFR conds across the local terminals. Brief SHRA will
cause VCSH across most of the local terminals through this
afternoon. TEMPO SHRA at TJBQ may temporarily reduce visibilities
and maybe briefly go MVFR but likely staying VFR. Winds to
continue from the east at about 10-15kt with gusts up to 25kt.

&&

.MARINE...Small craft advisories continue for most of the local
waters due to seas up to 8 feet. The local buoys confirm that the
winds and seas are hazardous. There is also a high risk of rip
currents until tomorrow.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 75 83 76 83 / 30 40 40 40
STT 74 85 74 85 / 30 30 40 40

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
544 AM AST Wed Dec 21 2016

.SYNOPSIS...Tutt low and associated mid to upper level trough will
continue to lift west and north of the region through Thursday
while slowly weakening overhead. Surface high pressure ridge
extending southwards across the region from the north central
Atlantic will weaken today through Thursday as an induced surface
trough will continue westward across the region. By Friday and
into the weekend however the high pressure ridge is to reestablish
once again and build north of the region to maintain moderate east
to northeast trade winds. In the meantime, the prevailing easterly
trades will continue to transport pockets of low to mid level
moisture across the region today through the end of the week.

&&

.DISCUSSION...Scattered to locally numerous showers with isolated
thunderstorms will remain possible today through Thursday due to
the instability aloft and good low level moisture convergence. Mid
to upper level is expected to weaken by Thursday but low level
moisture transport will continue through the end of of the work
week. Strong surface high pressure will shift farther east into
the eastern Atlantic but will keep moderate easterly winds over
the local area today. Another area of high pressure will enter
and move across the western Atlantic by Friday to maintain
moderate to strong east to northeast trade winds.

Trade wind moisture transport will increase today through the end
of the work week as both model guidance and present weather pattern
suggest that layered precipitable water values should increase to
near 2.00 inches across portions of the forecast area by Friday.
With that said expect scattered to numerous shower activity across
the coastal waters and the east coastal sections of the islands
during the late evening and early morning hours.

As the upper trough slowly weakens on Thursday, expect less favorable
conditions for thunderstorm development but the potential for short
duration and fast moving shower activity will continue. On Friday, a
short wave trough will move through the region and this should provide
sufficient support for isolated thunderstorm development.

By the weekend, the prevailing northeast wind flow will maintain
shallow moisture advection through the weekend across the coastal
waters and portions of the islands. This persistent pattern will
more than likely support periods of passing showers over the local
waters, U.S Virgin Islands, and eastern and northern PR during
overnight and early morning hours, followed by isolated to scattered
afternoon convection each day. most of the afternoon convection however
should be focused mainly over portions of central and west interior
section of Puerto Rico with lesser shower activity expected elsewhere.

&&

.AVIATION...SHRA/TSRA in srn part of Leeward Islands to cont thru
arnd 21/21z. Elsewhere unstable conds will generate isold TSRA
especially ovr PR aft 21/16z. Trade winds diminishing but sfc
winds at coastal airports will ocnly reach 15 gust to 25 kt with
hir gusts psbl in TSRA. Some mtn obscurations. Winds alf easterly
15-25 kt blo FL200. Strongest upr lvl winds arnd 25 kt from the
west at FL400.


&&

.MARINE...Hazardous seas will continue up to 8 feet across much
of the regional waters for the rest of the week. Trade winds are
expected to continue at 15 to 20 knots today, decreasing to 10 to
15 knots by Friday. Isolated thunderstorms today across the Atlantic
and caribbean waters due to an upper level trough. Extended the High
Rip Current Risk through later tonight for PR, Culebra Vieques and
St. Croix. Please refer to the latest Coastal Hazard Message (CFWSJU)
and Surf Zone Forecast (SRFSJU) for detailed information.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 83 76 83 76 / 40 40 40 30
STT 85 74 85 75 / 30 40 40 30

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
129 PM AST Wed Dec 21 2016

.SYNOPSIS...Mid to upper level trough/TUTT over the region
will prevail until Thursday. This trough aloft is enhancing
the convective instability over the local area...especially the
Caribbean Waters south of the Puerto Rico. Then, a short wave
trough will swing across the forecast area on Friday...maintaining
a relatively moist pattern through at least Saturday Morning.
Conditions will gradually improve late Saturday into Christmas
Day as drier and more stable air mass move over the local islands.

&&

.DISCUSSION...Cloudiness, scattered showers and isolated
thunderstorms have persisted across the Eastern Caribbean as an
upper level trough/TUTT dominates the region. Some showers moved
inland over Southeast Puerto Rico early this morning while most
showers and thunderstorms remained over the Caribbean Waters this
afternoon. The rest of today...showers and a few thunderstorms
are expected to develop across portions of the Cordillera Central
and Western Puerto Rico as well as the Caribbean Waters through
this evening. However...no significant rainfall accumulations are
anticipated with this activity.

Shower coverage across the forecast area could diminish overnight
into Thursday Morning as an area of drier air moves into the
region. However...conditions will become moist and unstable once
again on Friday as a short-wave upper level trough approaches
from the west-northwest. In the wake of the trough...conditions
will gradually improve Saturday afternoon into Christmas Day.
Trade winds are forecast to increase across the local region early
next week as another surface high pressure builds over the Western
Atlantic.

&&

.AVIATION...VFR conds expected through the local terminals today
with VCSH through the forecast period. Winds generally 10-20kt
with occasional gusts and from the east. Brief SHRA expected
overnight across the local area, causing VCSH across the terminals
except for TJMZ. Winds diminishing overnight.

&&

.MARINE...Seas up to 8 feet across the offshore Atlantic waters
and winds up to 20 knots combine to cause hazardous marine and
surf zone conditions. As a result...a high risk of rip currents
and a Small Craft Advisory continue until at least Thursday morning
and Friday evening, respectively.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 76 83 76 85 / 30 50 50 40
STT 76 85 76 87 / 20 50 60 40

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
557 AM AST Thu Dec 22 2016

.SYNOPSIS...A drier air mass and a weakening upper level trough
will result in less shower activity today. An upper level trough
over the Western Atlantic is forecast to move near the region
Friday into Saturday. In addition, a surface trough is expected
to reach the islands from the East by Friday. These features will
enhance the potential for showers and thunderstorms across the
islands during the end of the workweek and into the weekend.

&&

.DISCUSSION...Satellite imagery and GPS Precipitable waters
showed a decreasing trend in the available moisture, resulting
little or no shower activity over land. Showers activity was
detected mainly across the Caribbean waters, but some passing
showers moved inland across the U.S. Virgin Islands, North and
East Puerto Rico. The minimum temperatures were in the low 60s
over the interior sections of Puerto Rico, and between the mid 70s
and low 80s in the coastal areas of the U.S. Virgin Islands and
Puerto Rico.

The northeast wind flow will bring periods of showers across East
and Southeast Puerto Rico this morning. But in general, the
islands should observe a mixture of sunshine and clouds with
little to no shower activity. However, there is enough
instability and moisture to combine with the local effects to
produce showers and isolated thunderstorms mainly over Southwest
Puerto Rico during the afternoon.

An upper level trough is forecast to move over the region as a
short wave trough between Friday and Saturday. Also, a surface
trough is expected to move from the east across the local islands
by Friday. These features are expected to increase instability
to enhance convective development across the local region. As the
trough moves away...the weather conditions are forecast to
gradually improve into Christmas`s Day.

&&

.AVIATION...
LLVL moisture will increase behind a trof movg thru the
leeward islands arnd 22/12z. Periods of SHRA/MVFR cigs are expected
aft 22/16z persisting thru 23/06z for TNCM/TKPK. Trof passes thru
TIST/TISX arnd 23/06z with MVFR CIGS and VCTY SHRA aft 23/03Z--
mainly TISX. Wrn PR will see SHRA development aft 22/16z and some
mtn obscurations with brief MVFR conds in SHRA till 22/21Z in TJMZ
and TJBQ due to lcl convection. Isold TSRA psbl. Otherwise VFR
conds will prevail. Winds E 10 to 18 kt up thru FL180.

&&

.MARINE...
Marine conditions are expected to improve across the coastal
waters this morning. The local buoys are observing seas between 3
and 5 feet. Therefore, the small craft advisory will expire at 8
am. However, seas between 6 and 8 feet and winds up to 20 knots
are expected across the Atlantic offshore waters and the Anegada
Passage. As a result, the small craft advisory will continue at
these waters through at least the upcoming weekend.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 83 76 85 75 / 50 50 30 50
STT 85 76 87 74 / 50 50 30 60

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
140 PM AST Thu Dec 22 2016

.SYNOPSIS... Upper level trough overhead will shift northeast of
the region today but will be reinforced by a short wave trough
which will move across the southwest Atlantic today then sink
southwards and become amplified across Hispaniola and just west
of the region by Friday afternoon. Surface high pressure centered
across the northeast Atlantic, and an induced surface trough
across the northeastern Caribbean, will help maintain an east to
northeast trade winds across the forecast area. Satellite imagery
showed fragments of shallow trade winds moisture and accompanying
light to moderate showers moving across the regional waters.

&&

.DISCUSSION...

Overall a much drier weather pattern in place today as the upper
trough axis will lift just northeast of the region and a drier air
mass will filter in. Therefore the islands should experience mixture
of sunshine and clouds with limited shower activity over land. However,
sufficient instability aloft and available moisture will combine with
the local effects to produce showers and and possibly an isolated
thunderstorm mainly over southwest Puerto Rico during the afternoon.
Limited or no shower activity is expected elsewhere.

The reinforced upper level trough is forecast to move to just
west of the region by Friday. This alignment of the trough axis
along with the lingering surface trough will provide good
instability/divergence aloft along with low level moisture convergence
to support convective development Friday through early Saturday when
conditions will be most favorable.

As the upper trough lifts northwards once again by Saturday afternoon,
expect the surface high pressure ridge to build across the west Atlantic
and north of the region. By then expect the weather conditions to gradually
improve during the rest of the weekend and on Christmas Day under
a cooler and drier airmass. Still however expect the increasing
moderate to fresh northeast trade winds will continue to transport
periods of shallow cloudiness and passing showers across the
region especially during the late evening and early morning hours
each day.

&&

.AVIATION...VFR conds expected through 23/06Z. ENE winds at around
10-15KT today, decreasing after 22/22Z. VCSH possible across TJSJ, TJPS
and TJMZ after 22/19Z and across most of the local terminals
overnight as moisture increases causing SHRA to move in, affecting
the Leewards in the evening and reaching the USVI by Midnight
while it continues to move west. Most of the local flying area
will be observing passing SHRA by 23/18Z. TEMPO MVFR conds are
possible for the moments that the passing SHRA affect the
terminals.


&&

.MARINE...Local Seas are expected to slightly improve across portions
of the nearshore waters during the rest of the day. Local buoys
continued to observe Seas between 3 and 5 feet. However, Seas between
6 to 8 feet and winds up to 20 knots were observed over the
offshore Atlantic waters and the Anegada Passage. As a result, the
Small Craft Advisories will continue for these coastal waters
through at least the upcoming weekend.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 76 83 74 84 / 50 50 40 40
STT 74 84 74 86 / 50 50 50 50

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
550 AM AST Fri Dec 23 2016

.SYNOPSIS...Short wave trough will move across the southwest
Atlantic and become amplified across Hispaniola and just west of
the region by this afternoon. Surface high pressure centered
across the northeast Atlantic, and an induced surface trough
across the northeastern Caribbean, will help maintain an east to
northeast trade winds across the forecast area.

&&

.DISCUSSION...Passing showers were observed across the local
islands overnight. Some of these showers affected the San Juan
metropolitan area with rainfall accumulation of less than half
inch. A moist and unstable airmass will encompass the local region
today. In addition, troughiness will remain across the area. As
a result, scattered to numerous showers with thunderstorms are
expected to affect the region mainly this afternoon.

Moisture will erode Sunday as a mid to upper level ridge builds
across the area. This will result in fair and stable weather
conditions Sunday into early next week. Seasonable temperatures
will continue under ENE winds. At this time, pleasant weather
conditions are expected for Christmas day, with only some passing
showers expected from time to time.

&&

.AVIATION...SHRA expected to increase across the region today.
Some of these SHRA/-SHRA are expected to move across TJSJ/TIST/TISX
and TNCM/TKPK during the morning hours. Around 23/16z, mnt top and
BKN cigs expected along the interior/East/West PR. Under the Trough
pattern, TSRA development is likely today. Therefore, VCTS were
included and possible MVFR conds are possible this afternoon. Low
level winds ENE at 10-15 kts with higher gusts after 23/14z.

&&

.MARINE...Choppy seas up to 8 feet and winds up to 20 knots are
expected over the coastal waters. Small craft advisories are in
effect for all coastal waters except for the coastal waters of
western and southern Puerto Rico.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 84 75 84 75 / 60 50 50 30
STT 84 75 85 75 / 50 40 40 30

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
137 PM AST Fri Dec 23 2016

.SYNOPSIS...Mid to upper level short wave trough will continue to move
across the southwest Atlantic and cross the northeast Caribbean today
through Saturday. Surface high pressure centered across the northeast
Atlantic, and an induced surface trough across the northeastern Caribbean,
will help maintain an east to northeast trade winds across the forecast
area through early Saturday.The surface high pressure is to then build
north of the region resulting in moderate to strong northeasterly trade
winds.

&&

.DISCUSSION...Induced surface trough will linger across the eastern
Caribbean today. This pattern will allow patches of low level moisture
to converge across the region...resulting in increasing precipitable
water to near 2.00 inches in some areas through early Saturday. By
Saturday afternoon...the winds are to become more northeasterly and
bring a cooler and dryer air mass across the forecast area.

Based on the local synoptic pattern and recent model guidance, the
short wave trough is still expected to lift east northeast across
the region today through early Saturday. In the meantime expect
the favorable upper level divergence across the region to support
convective development throughout the day, and overnight through
early Saturday. Some of the afternoon convection today may lead
to ponding of water on roadways and possible minor flooding of
urban and small streams and poor drainage areas.

For the remainder of Saturday and on Christmas day expect mid to
upper level cap inversion to reestablish once again as the ridge
will gradually build aloft and north of the region. This will
support lesser low level moisture transport and a decrease in
moisture convergence across the area. However, the increasing
moderate to fairly strong northeasterly trade winds will continue
advect periods of shallow low to mid level cloudiness with embedded
cool showers across the coastal waters and portions of the islands
from time to time through the remainder of the weekend and into
the early next week. As a result passing showers and mostly light
to moderate late evening and early morning and afternoon showers
can be expected with less potential for thunderstorm activity at
least until the middle of next week.

&&

.AVIATION...VCSH/VCTS possible across the local terminals,
especially the PR terminals until 23/23Z as SHRA and ISOLD TSRA
develops over PR in the afternoon. Winds to continue from the
East to ENE today with sea breeze variations at about 10-15KT.
Overnight brief SHRA will affect the local area, causing VCSH
across most of the local terminals. Overnight winds to decrease to
5-10KT but remaining from the ENE.


&&

.MARINE...Small craft advisory/SCA remain in effect for the
Anegada passage and the offshore Atlantic waters. The rest of the
local waters, except the nearshore waters to the west of PR and
the nearshore Caribbean waters will go into Small Craft Advisory
this evening as Winds and Seas are expected to increase and meet
the criteria for SCA. High risk of rip currents will continue
for North and East facing beaches of PR as well as St Croix.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 75 84 75 84 / 50 50 30 30
STT 75 85 75 86 / 40 40 30 30

&&

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
536 AM AST Sat Dec 24 2016

.SYNOPSIS...Surface high pressure centered across the northeast
Atlantic, and an induced surface trough across the northeastern
Caribbean, will help maintain an east to northeast trade winds
across the forecast area. The surface high pressure is to then
build north of the region resulting in moderate to strong
northeasterly trade winds. Passing showers will affect the local
region from time to time.

&&

.DISCUSSION...No major changes in weather conditions expected for
today and Christmas day. Scattered showers affected the local area
overnight. These showers were moving quickly without any significant
rainfall accumulation observed. Local area will remain under the
influence of a surface high pressure system located across the
northeast Atlantic. Another stronger high pressure will exit the
eastern U.S early next week which will maintain fresh to strong
trade winds across the region. These trade winds will continue to
transport patches of low level moisture across the region next
several days. No big changes in this weather pattern is expected
for the upcoming days.

&&

.AVIATION...Brief periods of SHRA embedded in the trades are
expected to affect the windward areas of the local islands early
this morning. However, mostly VCSH are expected across the
Leewards, USVI and TJSJ taf sites. Winds will increase to 15 to
20 knots after 24/13Z.

&&

.MARINE...hazardous marine conditions are expected to continue as
strong trade winds maintain choppy seas across the region. Small
Craft advisories in effect for most coastal waters as seas up to 8
feet and winds up to 20 knots are expected.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 85 75 85 76 / 50 30 20 30
STT 85 76 86 76 / 50 30 20 30

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
157 PM AST Sat Dec 24 2016

.SYNOPSIS...Surface high pressure across the northeast Atlantic,
and an induced surface trough across the northeastern Caribbean,
will maintain east to northeast trade winds across the local area.
A surface high pressure will build north of the region resulting
in moderate to strong northeasterly trade winds. Passing showers
will affect the local region from time to time today, drier air
moving in tonight will cause a decrease in shower activity.

&&

.DISCUSSION...Scattered showers have been observed across the
local area today, particularly across the eastern, northern, and
western sections of PR. The central and southern portions of PR
have observed little to no rain today. Most of the passing showers
are light to moderate as they pass by, some of them leaving about
a quarter of an inch of rain or so which causes minor ponding of
water in poor drainage areas.

This shower activity is expected to gradually improve as they day
progresses because there is drier air moving in from the east
northeast, and by tonight there should be only isolated and mostly
light showers. Therefore the forecast shows only isolated to
scattered showers this evening, then only isolated showers by
Christmas morning. In addition, it will be breezy for the rest of
today and for the next several days, gusty near showers.

Having said that, mainly isolated to scattered passing showers are
expected for the next several days, especially after Sunday since
moisture is expected to increase a little starting on Monday.
Winds will prevail from the East-Northeast through Tuesday, then
turning more easterly thereafter. Temperatures for the next
several days should be seasonable.

&&

.AVIATION...VFR conds expected to prevail across the forecast area
with brief MVFR conds possible in SHRA/VCSH at Leeward/USVI
terminals as well as JSJ through the forecast period. E winds 15-20
knots becoming 10 knots or less overnight.

&&

.MARINE...Small craft advisories are in effect for most of the
local waters except the nearshore Caribbean and those of western
PR. Seas are hazardous due to fresh winds and seas up to 8 feet.
High risk of rip currents continue for the beaches of northern PR
as well as northern and eastern St Croix.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 75 85 76 82 / 30 20 30 30
STT 76 86 76 86 / 30 20 30 30

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
540 AM AST Sun Dec 25 2016

.SYNOPSIS...Surface high pressure across the northeast Atlantic,will
maintain east to northeast trade winds across the local area. Passing
showers will affect the local region from time to time today. Drier
air moving in later today will cause a decrease in shower
activity.

&&

.DISCUSSION...Isolated passing showers were observed across the
local area overnight. Most of these showers affected the eastern
half of Puerto Rico. Early this morning, an area of drier air was
starting to move in across the region from the east. A decrease in
shower activity is expected today.

A surface high pressure system will maintain an east to northeast
trade wind flow across the region next several days. These winds
will continue to transport patches of low level moisture across
the region next several days. Temperatures for the next
several days should be seasonable.

&&

.AVIATION...Passing -SHRA/SHRA expected during the morning hrs. Some
of this activity will move across TJSJ/TIST/TISX/TNCM/TKPK. Mostly
sunny skies during the afternoon. NE winds at 10 to 20 knots and
gusty.

&&

.MARINE...Small craft advisories are in effect for most of the
local waters except the nearshore Caribbean and those of western
PR. Seas are hazardous due to fresh winds and seas up to 8 feet.
High risk of rip currents continue for the beaches of northern PR
as well as northern and eastern St Croix.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 86 76 82 76 / 20 20 30 40
STT 86 75 86 75 / 20 20 30 40

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
125 PM AST Sun Dec 25 2016

.SYNOPSIS...A generally fair and mainly stable weather pattern
will continue to prevail across the local islands during the
next several days under a mid to upper level ridge and low level
moisture near normal values. Surface high pressure north of the
area will continue to promote fresh east northeast winds through
midweek.

&&

.DISCUSSION...Mostly sunny to partly cloudy skies prevailed across
the local islands during the morning and early afternoon hours.
Although passing showers were noted across north and east PR as
well as USVI, no significant accumulation was observed. Temperatures
were in the mid 80s along coastal areas with ENE winds 15 to 20 MPH
as well as occasional higher gusts. A seasonable weather pattern will
continue to prevail across the local islands much of this week with
passing showers embedded in the trades at times. These brief showers
may affect windward areas, particularly during the evening and
early morning hours. The frequency of passing showers may increase
Friday and into the upcoming weekend as low level moisture pools
across the forecast area under weakening ridge aloft. Seasonable
temperatures will continue.

&&

.AVIATION...VFR conds expected to prevail across the forecast
area with brief MVFR conds possible in -SHRA/VCSH at Leeward/USVI
terminals as well as JSJ through the forecast period. ENE winds
15-20 knots becoming 10 knots or less overnight.

&&

.MARINE...Small craft advisories remain in effect for most of the
local waters except the nearshore Caribbean and those of western
PR. Seas continue hazardous due to fresh northeast trade winds and
seas up to 8 feet. High risk of rip currents continue for the
beaches of northern/eastern PR as well as northern and eastern
St Croix.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 76 82 76 82 / 20 30 40 40
STT 75 86 75 85 / 20 30 40 40

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
533 AM AST Mon Dec 26 2016

.SYNOPSIS...A generally fair and mainly stable weather pattern
will continue to prevail across the local islands during the
next several days under a mid to upper level ridge and low level
moisture near normal values. Surface high pressure north of the
area will continue to promote fresh east northeast winds through
midweek.

&&

.DISCUSSION...Isolated passing showers were observed across the
local area overnight. Most of these showers affected the eastern
half of Puerto Rico. Winds have shifted more northeasterly
overnight.

A surface high pressure system will maintain an east to northeast
trade wind flow across the region next several days. These winds
will continue to transport patches of low level moisture across
the region next several days. Temperatures for the next
several days should be seasonable. No big changes in this weather
pattern is anticipated the rest of the work week.


&&

.AVIATION...VFR conditions expected throughout the forecast period.
Passing showers may affect TJSJ/TJBQ/TIST/TISX/TNCM/TKPK during the
early morning hours. In the afternoon, showers may continue to
affect TJSJ/TJBQ/TJMZ but skies will remain mostly clear to partly
cloudy across the region with the lowest cloud deck around 2500
feet. NE winds between 10 and 20 knots and gust will prevail.

&&

.MARINE...Small craft advisories are in effect for most of the
local waters except the nearshore Caribbean and those of western
PR. Seas are hazardous due to fresh winds and seas up to 8 feet.
High risk of rip currents continue for the beaches of northern and
southeastern PR, Culebra as well as northern and eastern St
Croix.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 83 76 82 75 / 30 40 40 10
STT 86 75 85 74 / 30 40 40 10

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
152 PM AST Mon Dec 26 2016

.SYNOPSIS...Trade wind pattern will prevail across the forecast
area through the end of the week. Surface high pressure north of
the area will continue to push patches of low level clouds and
light showers over the windward areas at times. No significant
changes in the local weather is anticipated the rest of the week.

&&

.DISCUSSION...Generally stable conditions have prevailed across
the local area under the influence of a mid to upper level ridge.
Breezy with sunny to partly cloudy skies have been observed across
the Northeast Caribbean today. Light passing showers embedded in
the trade winds have resulted in brief periods of showers across
the north and east Puerto Rico as well as the U.S. Virgin Islands
from time to time. The rest of today and tonight...a few passing
showers are still possible across the windward areas with light
rainfall accumulations.

Stable conditions will continue over the next several days. Moisture
should remain at normal or below normal for this time of the year
most of the week. Therefore...the conditions are not favorable for
thunderstorms or significant rainfall accumlations. However...light
showers will continue to pester the north and east portions of
the islands as brisk northeasterly winds will push light showers
inland.

&&

.AVIATION...Mostly VFR conditions expected across all terminals
through the forecast period. Trade wind showers will continue over
the waters with some reaching sections of the islands creating brief
-RA/VCSH at times. Low level winds will continue from the ENE
between 15-25 knots.

&&

.MARINE...Fresh winds and choppy seas will prevail across most of
the waters over the next couple days. As a result...Small Craft
Advisories and a high risk of rip currents continue through late
Tuesday night. Marine conditions may improve Friday into the weekend.
Hazardous marine conditions are forecast again next week.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 76 82 75 83 / 40 40 10 10
STT 75 85 74 85 / 40 40 10 10

&&

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
549 AM AST Tue Dec 27 2016

.SYNOPSIS...Trade wind pattern will prevail across the forecast
area through the end of the week. Surface high pressure north of
the area will continue to push patches of low level clouds and
light showers over the windward areas at times. No significant
changes in the local weather is anticipated the rest of the week.

&&

.DISCUSSION...Same weather pattern continues. Trade winds will
continue to bring patches of low level moisture across the region
from time to time. Winds are expected to shift more easterly today
and then east southeast by Wednesday and Thursday as surface high
pressure northeast of the area moves east. As a result, winds are
expected to diminish somewhat by Friday and Saturday. However, for
late Saturday into Sunday, an increase in winds will return to the
region as another strong high pressure system will build across
the Atlantic.

Stable conditions will continue over the next several days. Moisture
should remain at normal or below normal for this time of the year
most of the week. Therefore...the conditions are not favorable for
thunderstorms or significant rainfall accumulations.
However...light showers will continue to affect the north and east
portions of the islands as brisk northeasterly winds will push
light showers inland.

&&

.AVIATION....Mostly VFR conditions expected across all terminals
throughout the forecast period. Isolated to scattered showers will
continue over the regional waters with some reaching eastern and
northern portions of the islands. This will create brief -RA/VCSH at
times during the overnight and early morning hours. Winds will
continue from the ENE at 10 to 15 knots increasing to 15- 20
knots in the morning with higher gusts. Winds will shift more from
the east during the late afternoon and early evening hours. Trade
winds showers will once again bring -RA/VCSH conditions in the
afternoon, especially for TJSJ and TJBQ terminals.


&&

.MARINE...Fresh easterly wind driven seas will continue to
create hazardous and choppy seas across most of the waters over
the next couple days. As a result...Small Craft Advisories and a
high risk of rip currents will continue through Wednesday. Marine
conditions are still expected to gradually improve by Friday and
into the next weekend.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 84 75 84 73 / 40 10 10 20
STT 85 73 85 74 / 40 10 10 20

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
201 PM AST Tue Dec 27 2016

.SYNOPSIS...Breezy conditions continue to be expected for the next
several days with partly cloudy skies and brief passing showers
across the local area. Moderate to high risk of rip currents and
hazardous marine conditions are expected for the next several
days as well. The surface High Pressure across the central
Atlantic will continue in place until later this week when another
surface High Pressure moves into the western Atlantic, keeping
breezy conditions over the local area. Broad upper level ridge
will continue near the local area through the week.

&&

.DISCUSSION...The limited available moisture has been enough to
combine with the local effects and produce isolated to scattered
brief showers over the local islands. Because of the moderate
winds these showers have been moving quickly and leaving very
minimal accumulations. Due to some sea breeze convergence, there
is a small area of SW-PR that has a bit thicker clouds and could
eventually produce a few moderate showers later in the afternoon.

Generally this same pattern is expected for the next several days.
Patches of moisture will continue to pass through and showers
embedded in the trades will affect the local area, particularly in
the overnight and morning hours across the local waters, USVI, and
eastern and northern PR. In the afternoons, showers may develop
across western PR but the winds are rather strong so the showers
affect land areas for a short amount of time before exiting to the
coastal waters.

&&

.AVIATION...Mainly VFR conditions expected across all terminals
through the forecast period. However, trade wind showers on a 15-
20kt ENE wind flow will continue across the flying area creating
brief -RA/VCSH at times across the Leeward/USVI and eastern PR
terminals.

&&

.MARINE...Seas will continue to be hazardous under a northerly
swell and moderate to fresh winds. This is why there is a small
craft advisory across most of the local waters due to seas up to 8
feet. There is also a high risk of rip currents across the
northern beaches of PR as well as some beaches in Culebra and
Saint Croix.


&&

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

&&

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
515 AM AST Wed Dec 28 2016

.SYNOPSIS...A seasonable weather pattern will continue to prevail
through at least Friday under a mid to upper level ridge and low
level moisture near normal values. Low level moisture may increase
by the end of the workweek and into the upcoming weekend. This
may increase the frequency of passing showers across the local
islands.

&&

.DISCUSSION...Ridge pattern aloft will continue to prevail across
the forecast area during the next several days. Although, there is
a weakening expected at upper levels by the end of the week; the
mid level component will continue to hold through at least next
week. At lower levels, migratory highs north of the area will
continue to promote a generally fresh easterly wind flow through
Thursday. Winds are expected to become moderate on Thursday and
slightly from the southeast Friday as a shearline dissipates north
of the area. The aforementioned shearline may induce a surface
trough across the northeast Caribbean which will result in
moisture pooling across the forecast area late Fri-Sat.

Therefore, continue to expect passing showers across USVI and E
PR in the late evening and early morning hours today through Fri.
The frequency of these showers may increase by the end of the
workweek and the first part of the weekend as moisture pools
across the area. Although convection likely due to sea breeze
convergence, still expect shallow activity due to the lack of
upper level forcing.

&&

.AVIATION...Mostly VFR conditions expected across all terminals
throughout the forecast period. Isolated to scattered passing
showers will continue over the regional waters with some reaching
the Leeward islands, as well as eastern and northern Puerto Rico.
This will create brief -RA/VCSH at times during the overnight and
early morning hours. Winds will continue from the east at 10 to 15
knots with occasionally higher gusts throughout the day. A sea breeze
component will dominate TJMZ and TJBQ during the late morning hours,
but will become more from the east once again in the early afternoon
hours. Trade winds showers will once again bring -RA/VCSH conditions
in the afternoon, especially for the TJSJ, TJBQ, TIST and TISX.

&&

.MARINE...Fresh easterly winds will continue to prevail across
the regional waters through at least Thursday. This will continue
to result in choppy and hazardous seas today and tomorrow with
seas BETWEEN 6 and 8 feet. Seas will briefly subside as the local
pressure gradient weakens by the end of the workweek. A high risk
of rip currents continues for the Atlantic shoreline of PR,
Culebrita Beach and Saint Croix.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 85 77 86 77 / 20 30 30 20
STT 86 77 86 77 / 20 30 30 30

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
205 PM AST Wed Dec 28 2016

.SYNOPSIS...A ridge aloft will continue at upper levels during the
next few days. At mid levels, a weak trough is observed to the
north of the region. A surface high pressure, located in the
Central Atlantic will continue to push trade wind showers at
times across the islands. This weather pattern is expected to
continue through the forecast period. Surface moisture may
increase on Friday. This could result in a slight increase in the
frequency of trade wind showers.

&&

.DISCUSSION...
A mixture of sunshine and clouds with isolated trade wind showers
prevailed across the region today. Pleasant seasonal temperatures
were observed across the U.S. Virgin Islands and Puerto Rico this
morning. This seasonable weather pattern is expected to continue
at least until tomorrow. As a result, expect quick trade wind
showers from time to time across the windward sections of Puerto
Rico and the U.S. Virgin Islands the rest of today and during the
overnight hours. Then, limited convection still possible across
the interior and western sections of Puerto Rico and downwind from
the U.S. Virgin Islands during the afternoon. However, no
significant rainfall accumulation is expected at this time.

Model guidance are suggesting an induce surface trough associated
to a weak shearline by the end of the workweek into the weekend.
This feature may support moisture pooling across the region by
Friday into Saturday. If the guidances are correct, expect a slight
increase in the frequency of trade wind showers during that
period. In addition, a weak upper level trough is forecast to
swing across the region Saturday into Sunday. This pattern could
provide additional instability to increase shower activity across
the region.

&&

.AVIATION...VFR conditions expected to prevail across all terminals
through the forecast period. SHRA could increase after 29/00z
between the USVI and eastern PR terminals. This could result in
brief periods of RA/VCSH between 29/00z-29/10z. Low level winds E-
ESE at 10-20 kts...but light and variable at the sfc overnight.

&&

.MARINE...Latest buoy data across the surrounding waters of the
islands are indicating seas between 4-6 feet and east winds at
around 15 knots. Small craft advisories remain in effect for most
of the waters due to possible 7 ft seas and a high rip current
risk continues in effect for the northern beaches of Puerto Rico,
Culebra and St. Croix.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 77 86 77 85 / 30 30 20 20
STT 77 86 77 84 / 30 30 30 30

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
545 AM AST Thu Dec 29 2016

.SYNOPSIS...Passing showers embedded in the trades will continue
to prevail across the U.S. Virgin Islands and the eastern half of
Puerto Rico. Moisture advection is expected Fri-Sat as a shearline
north of the forecast area induces a surface trough across the
northeast Caribbean. A fair weather pattern is expected early next
week.

&&

.DISCUSSION...Mostly clear to partly cloudy skies were observed
across the local islands during the overnight and early morning
hours. Scattered passing showers were observed over the local
waters as well as USVI and E PR, leaving minimal accumulations.
Overnight minimum temperatures were generally from 70 to 75 degrees
at lower elevations. Winds were mainly light and variable.

A mid level ridge will strengthen Thu-Fri, and hold across the
area through early next week. At lower levels, migratory highs
north of the area will continue to promote a generally fresh
easterly wind flow. However, as the shearline dissipates north of
the area, expect moderate east southeast winds Thu-Fri. The
aforementioned shearline will induce a surface trough across the
northeast Caribbean Fri-Sat which will promote moisture advection.
Although low level moisture is expected to increase, mid levels
will remain dry.

As a result, continue to expect passing showers across USVI and E
PR in the late evening and early morning hours today and Fri. The
frequency of these showers may increase as moisture pools across
the area. Afternoon convection is likely Thu-Sat due to weakening
trades which will allow sea breeze convergence, but still expect
shallow activity due to the lack of upper level forcing. A generally
fair and mainly stable weather pattern is expected early next
week.

&&

.AVIATION...Prevailing VFR conds expected through the next 24
hours across the local terminals. Passing SHRA across the local
area is causing VCSH across most of the terminals and will likely
continue through the day. SHRA development across NW-PR may cause
SHRA to affect TJBQ between 29/18Z and 20/21Z, possibly causing
brief moments of MVFR conds. Easterly winds at 5-10KT expected
through 29/14Z, increasing to 10-15KT thereafter with sea breeze
variations.

&&

.MARINE...A moderate to fresh easterly wind flow will prevail
across the regional waters through the upcoming weekend. Seas
will briefly subside as the local pressure gradient weakens.
However, seas and winds are expected to increase once again
early next week. Small Craft advisories remain in effect until
this evening as well as the High Risk of Rip Currents. Seas 6
to 8 feet and subsiding.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 86 75 87 76 / 30 20 20 10
STT 85 76 86 75 / 30 30 30 20

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
101 PM AST Thu Dec 29 2016

.SYNOPSIS...Surface high pressure will continue across the
Central Atlantic promoting east to southeast winds through Friday.
Prefrontal trough moves over La Hispaniola from the Atlantic
offshore waters, promoting moisture advection across the area.
Associated front will remain over the open Atlantic waters. Strong
surface high pressure will tighten the pressure gradient once
again late Saturday into early next week, promoting a fresh to
locally strong east-northeast trade wind flow. Broad mid to upper
ridge across the Caribbean basin will persist for the next several
days.


&&

.DISCUSSION...Fair weather and mostly sunny skies prevailed today
across the forecast area. A few clouds were forming due to local
effects across the U.S. Virgin Islands and western Puerto Rico
early in the afternoon. Some shower activity is expected to
develop from this in form of streamers off the islands and in
isolated to locally scattered over portions of western PR by mid
afternoon. Overall fair weather conditions should prevail through
the forecast period.

Prefrontal trough across the Hispaniola and the Atlantic waters
will increase moisture content and advection across the islands,
specially on Friday through late Saturday night. From Sunday
onwards, strong surface high pressure will promote fresh to
locally strong northeasterly trades with quick passing showers
moving from time to time across the U.S. Virgin Islands and the
northern and eastern sections of Puerto Rico. Seasonable
temperatures will continue across the islands for the next several
days.


&&

.AVIATION...VFR conditions expected through 30/18z. An isolated
shower or two may show up in the vicinity of some of the local TAF
sites...but not significant impact on operations expected. SFC winds
will be mainly E-SE at 10-15 kts daytime and 5-10 overnight with
local sea breezes variations.


&&

.MARINE...Frontal boundary moving from the western Atlantic into
the Central Atlantic waters between two high pressures will relax
the pressure gradient for the next couple of days. Winds and seas
should continue to subside. However, surface high behind the front
will increase winds and seas once again late in the weekend into
early next week. Small craft advisories will be required for much
of the Atlantic waters and passages.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 75 87 76 84 / 20 20 10 30
STT 76 86 75 83 / 30 30 20 30

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
516 AM AST Fri Dec 30 2016

.SYNOPSIS...Showers embedded in the trades are expected at times
across US Virgin Islands as well as eastern Puerto Rico followed
by shallow afternoon convection over northwest Puerto Rico.
Moisture advection still expected as a shearline north of the
forecast area induces a surface trough across the northeast
Caribbean. A fair weather pattern is expected Sunday and into
midweek next week.

&&

.DISCUSSION...Partly cloudy skies were observed across the local
islands during the overnight and early morning hours. Scattered
passing showers were observed over the local waters as well as
US Virgin Islands and eastern Puerto Rico. Overnight minimum
temperatures were generally from 70 to 75 degrees at lower
elevations. Winds were mainly light and variable.

A shearline north of the forecast area will induce a short-lived
surface trough across the local islands which will promote moisture
advection through early Saturday. Although moisture is expected
to increase at lower levels, the mid levels will remain fairly dry.
As the aforementioned shearline and its associated surface trough
dissipates, a broad surface high pressure will build across the
western Atlantic and into the local area. This feature will hold
through at least midweek next week, bringing breezy conditions as
well as patches of low level moisture at times. Ridge pattern aloft
is also expected to strengthen.

As a result, continue to expect passing showers across USVI and E
PR in the late evening and early morning hours. The frequency of
these showers may increase late this evening and Saturday evening
as moisture advects across the eastern Caribbean. Afternoon convection
across west PR is likely this afternoon and Saturday afternoon
due to weaker trades which will allow sea breeze convergence,
but still expect shallow activity due to the lack of upper level
forcing.

A generally fair and mainly stable weather pattern is expected
Sunday afternoon and into midweek next week with trade wind
showers at times.

&&

.AVIATION...Prevailing VFR conds expected through the next 24 hours
across the local terminals. Sct brief SHRA moving across the area
through 30/14Z will continue to cause VCSH across the terminals
except for TJMZ. SHRA development across NW-PR is expected to affect
areas in and around TJBQ and TJMZ between 30/17Z and 30/22Z which
could affect the actual terminals briefly. Winds to continue from
the east at about 10KT through 30/14Z, slightly increasing
thereafter with sea breeze variations developing.

&&

.MARINE...Marine conditions will continue to improve through Saturday.
However, hazardous seas will come back early next week as strong
high pressure builds over the Western Atlantic. A moderate risk of
rip currents continues across most of the local waters.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 86 77 84 77 / 20 10 30 50
STT 85 77 83 77 / 30 20 30 30