Caribbean - Central America Weather

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
550 AM AST SUN AUG 28 2016

.SYNOPSIS...
The influence of Hurricane Gaston, well northeast of the region
across the Central atlantic, and a broad area of low pressure
near the Florida Straits, will continue to induce a moist
southeast wind flow across the region through at least Monday. A
TUTT Low to the Northeast of the area will retrogress westward to
meander across the region at least until Tuesday as an Upper level
ridge builds over the region by midweek.

&&

.DISCUSSION...
The proximity of a TUTT Low produced showers across the local
waters overnight, some of these showers, though they were brief,
moved inland across the windward sections of PR and the U.S.
Virgin Islands. In addition, the diffluence aloft induced the
formation of thunderstorms in the far Southwest corner, between
the Mona Passage and the local Caribbean Offshore waters.

The combination of the TUTT low, an induce surface trough and the
available low level moisture will continue to enhance shower
activity across the surrounding waters and some of these showers
are going to reach the windward sections of PR and the U.S. Virgin
Islands from time to time during the morning hours. Then, another
round of afternoon convection is expected along the Cordillera
Central and the western sections of Puerto Rico, but also, some
of these showers could affect the metropolitan area of San Juan.

As the TUTT low moves away from the region on Tuesday, a ridge
pattern aloft will build from the east northeast, over the
Northeast Caribbean. In addition, the surface winds are expected
to become from the east and precipitable water will drop near or
below normal by midweek. This pattern will result in limited
shower and thunderstorm activity across the local islands.

&&

.AVIATION...
Mostly VFR conditions expected over most of the local flying
area. However vicinity showers are possible until 28/14Z across
the Leeward and USVI taf sites. Isolated tstms will affect the
vicinity of TJSJ/TJBQ and TJMZ after 28/17 and through 28/23z with
mountain top obscuration across the Cordillera Central of PR. Low
level winds will be mainly east at 10 knots overnight increasing
to 10 to 15 knots after 28/13Z.

&&

.MARINE...A small, but long ENE swell, generated by Tropical
Cyclone Gaston will continue to affect the local Atlantic waters
and Anegada through at least late tonight, followed by arrival of
another small but long NE swell by late Tuesday. Although this
swells, seas are expected below 6 feet and winds around 15 knots.
At this moment, marine weather conditions are expected below small
craft criteria. However, isolated thunderstorms with areas of
locally heavy rainfall and dangerous lightning will remain
possible across the regional waters as the TUTT Low moves across
the region.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 90 78 91 80 / 30 20 30 10
STT 86 80 87 81 / 30 30 30 10

&&

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
144 PM AST SUN AUG 28 2016

.SYNOPSIS...Tutt low now centered just north of the northern
Leeward Islands will continue to slowly shift westward across the
region overnight through Monday. This pattern should briefly place
most of the forecast area on the subsident side of the upper trough
which will should be somewhat of a limiting factor for significant
convective development. However, the broad trough across the western
caribbean which extends into the southwest Atlantic will maintain
a sufficiently moist environment across the region today. Satellite
imagery showed mid to upper level cloud debris from convection around
the tutt low being transported southwards across the forecast area.

&&

.DISCUSSION...Although occasional transport of mid to upper level cloudiness
across the region is expected today ..still expect sufficient low level
moisture convergence and instability across the region to allow for
afternoon convection across parts of the islands. Over Puerto Rico.
because of the light wind flow, now expect most of the convection to
be focused across the interior and west to southwest sections of the
island. Over the U.S Virgin Islands any showers that do develop should
occur mainly on the windward side of the island steered by the prevailing
east southeast wind flow. Afternoon showers and thunderstorm activity
may produce locally heavy rainfall at times and could lead to minor
ponding of water on roadways and in poor drainage areas. Expect
the convection over land to diminish around sunset, leaving variably
cloudy to partly cloudy skies over land areas.

During the overnight and early Monday morning, showers and thunderstorms
are expected redevelop over the coastal waters surrounding the islands,
as the upper low and induced surface trough will enhance shower development
as it moves westward. Therefore showers may affect portions of the north
and east coastal areas and produce periods of moderate to locally heavy
rainfall. During the afternoon on Monday ...expect the tutt low to then
be in a position to favorable upper level instability and better chance
of enhanced afternoon convection across the northern half of Puerto
Rico.

A somewhat drier weather pattern is so far expected on Tuesday
and into the latter part of this upcoming week, as high pressure
will build aloft and to the north of the region with lesser tropical
moisture advection. However...sufficient moisture will be available
each day to allow for the typical passing early morning showers followed
by isolated to scattered shower activity across parts of the interior
and west sections of Puerto Rico with lesser activity expected for the
U.S Virgin Islands.

&&

.AVIATION...Showers and thunderstorms are possible for the southern
half of Puerto Rico and all USVI terminals until 28/22Z. Isolated
tstms will affect the vicinity of TJSJ...TJBQ and TIST after 29/04Z
and through 29/12z with mountain top obscuration across the
Cordillera Central of PR. Low level winds will be mainly east at 10
knots overnight increasing to 10 to 15 knots after 29/13Z.

&&

.MARINE...Tranquil marine weather conditions are expected to continue
through at least Tuesday. However, isolated thunderstorms with areas
of locally heavy rainfall and dangerous lightning will remain possible
across the regional waters as the TUTT Low moves across the region
overnight through Monday.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 78 91 80 92 / 20 30 10 10
STT 80 87 81 88 / 40 40 10 20

&&

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
527 AM AST MON AUG 29 2016

.SYNOPSIS...Meandering TUTT low north of the local islands will
continue to enhance shower and thunder activity across the local
Atlc waters. High pressure will build across the region Tuesday.

&&

.DISCUSSION...Some showers with thunderstorms were seen across the
coastal waters north of Puerto Rico...with little activity
observed over land areas. For this morning...some passing showers
can be expected...mainly across the U.S. Virgin Islands and
eastern Puerto Rico. For this afternoon...available moisture will
combine with daytime heating and a TUTT low relocating west of
the islands to produce isolated to scattered showers with
thunderstorms mainly along the Cordillera Central to the north
section of Puerto Rico.

High pressure will dominate the area Tuesday through at least
Friday...maintaining stable atmospheric conditions across the
region. Therefore...limited shower activity is expected across the
local islands...except during the afternoon hours mainly across
the western interior section of Puerto Rico.

&&

.AVIATION...Mostly VFR conditions expected across the west sections
of Puerto Rico, and the Lesser Antilles terminal during the morning
hours, on the other hand expect passing -SHRA from times at
TJSJ/TIST/TISX. Aft 29/17z, SHRA/TSRA expected to the north of the
Cordillera and across the eastern half sections of PR, affecting the
vicinity of TJSJ/TJBQ and TJMZ after 29/17 and through 29/22z with
mountain top obscuration across the Cordillera Central of PR. Low
level winds will be from the E-ESE at 10 to 15 knots after 29/13Z.

&&

.MARINE...Seas up to 5 feet and winds up to 15 knots are expected
over the coastal waters.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 92 80 92 80 / 30 10 10 20
STT 89 81 91 80 / 40 10 20 20

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
135 PM AST MON AUG 29 2016

.DISCUSSION...Still expecting showers and thunderstorms to develop
over the northwest portions of Puerto Rico. Although a few showers
started to develop over the northwest portions of PR they quickly
dissipated. Dry air have moved over the local region therefore
limiting the convective activity across the NW PR. Tonight expect
dry and stable conditions to dominate our local forecast area with
only a few isolated showers moving across the local waters.

High pressure will dominate the area Tuesday through at least
Friday...maintaining stable atmospheric conditions across the
region. Therefore...limited shower activity is expected across the
local islands...except during the afternoon hours mainly across
the western interior section of Puerto Rico.

&&

.AVIATION...Mostly VFR conds at most TAF sites. SHRA/ Isold TSRA
dvlpmnt will be possible ovr parts of the ctrl mtn range of PR, then
will steer towards the N and NW sections of the island til at least
29/22z. Expect prds of MVFR due to developing clds and SHRA/ Isold
TSRA vcty TJSJ... TJBQ and TJMZ til 29/22z w/psbl mtn top obscr. Few
streamerlike L/Lvl clouds w/SHRA btw Ern PR and Nrn Leewards, with
possible fair weather waterspouts in some areas based on recent
assessment tool guidance. L/LvL fm SE-S 10-15 kts blo FL150... then
veering and BCM fm w and incr w/ht abv. Expect lcl sea breeze
variations...but SFC wnd mainly fm SE 5-15 kts w/ocnl higher gust
til 29/22z.


&&

.MARINE...Seas up to 5 feet and winds up to 15 knots are expected
over the coastal waters. Hurricane Gaston located well NE of the
local region will continue to move across the Atlantic waters. A
small to moderate but long dominant period NE swell generated
from Gaston is expected to reach the local waters by Tuesday
morning.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 80 92 80 92 / 10 10 20 20
STT 81 91 80 90 / 10 20 20 20

[cycloneye]

A weak area of low pressure, associated with a tropical wave, is
moving off the coast of Senegal in western Africa. Environmental
conditions are expected to be favorable for gradual development of
this system later this week while it moves westward at 15 to 20 mph
over the eastern and central tropical Atlantic.
* Formation chance through 48 hours...low...near 0 percent
* Formation chance through 5 days...medium...50 percent

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
522 AM AST TUE AUG 30 2016

.SYNOPSIS...Upper level ridge will dominates the local region
through most of the week. An active tropical wave will approach
the northeast Caribbean by the weekend.

&&

.DISCUSSION...Some light passing showers were noted across the
local waters. No showers were observed over land areas. As the
TUTT low moves away from the local islands, a ridge pattern aloft
will build from the east northeast. Under building upper level
ridge, moderate easterly winds and precipitable water near or
below normal values, a seasonable weather pattern will prevail
through at least Thursday with a few locally induced afternoon
showers and thunderstorms over and west of the Cordillera Central
as well as warm to hot temperatures along the northern slopes of
Puerto Rico.

An active tropical wave is expected to approach the northeast
Caribbean during the weekend. An increase in shower and
thunderstorms activity is expected...mainly by early next week. At
this time...it is too early to know exactly how active this wave
will be across the region. Stay tuned.

&&

.AVIATION...VFR conditions expected across the local flying area
until 30/15Z. After 30/17Z, SHRA/TSRA expected to develop across
western and interior Puerto Rico, affecting the vicinity of TJMZ
through 30/22Z with mountain top obscuration. Low level winds will
be from the ESE at 15-25 knots.

&&

.MARINE...Seas up to 5 feet and winds up to 20 knots are expected.
Small craft should exercise caution across the Atlantic waters.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 92 81 92 80 / 20 20 20 20
STT 90 80 91 80 / 20 20 20 20

[cycloneye]

A weak area of low pressure, associated with a tropical wave, is
located over the far eastern Atlantic near the Cabo Verde
Islands. Environmental conditions are expected to become a little
more favorable for some gradual development of this system late this
week while it moves westward at 15 to 20 mph over the tropical
Atlantic.
* Formation chance through 48 hours...low...near 0 percent
* Formation chance through 5 days...medium...40 percent

[cycloneye]

2 PM TWO.

A weak area of low pressure, associated with a tropical wave, is
located over the far eastern Atlantic near the Cabo Verde
Islands. Environmental conditions are expected to become a little
more favorable for some gradual development of this system late this
week while it moves westward at 15 to 20 mph over the tropical
Atlantic.
* Formation chance through 48 hours...low...near 0 percent
* Formation chance through 5 days...medium...40 percent

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
155 PM AST TUE AUG 30 2016

.SYNOPSIS...Mid to upper ridge building from the northeast will
hold through the end of the work week. Saharan air layer will
continue to create hazy skies through Wednesday, returning once
gain by early in the weekend. Weak wave increases moisture later
on Thursday. A stronger wave is forecast to be close to the
forecast area by Sun-Mon next week. Surface high pressure will
continue across the Atlantic. TC Gaston will continue to move
further to the northeast across the open Atlantic.


&&

.DISCUSSION...Sunny to partly cloudy skies prevailed Today across
the local islands. Hazy skies due to Saharan dust and fair
weather conditions persisted through the early afternoon hours.
Ridge aloft will continue to maintain fair weather conditions
across the islands for much of the forecast period. Limited shower
activity is expected each day, with streamers developing off the
islands and shallow afternoon convection over sections of western
PR. Trade wind showers could bring brief periods of light rains
across the USVI and eastern PR during the overnight hours. A weak
wave will enter the local area by late Thursday, increasing
moisture and the chances for showers across the islands. Another
SAL moves across the islands during the weekend followed by an
active tropical wave by early next week.


&&

.AVIATION...VFR conds expected across the local flying durg entire
prd. VFR...Few cld lyrs FL025...FL050...Sct-Bkn FL200-250. Mostly
Isold SHRA mainly ovr W interior PR and vcty TJMZ...TJBQ. L/lvl wnds
fm E-SE blo FL200 bcmg fm S and incr w/ht abv. No sig operational wx
hazards expected across the local flying area attm.


&&

.MARINE...Seas will increase up to 6 feet on Wednesday across
the offshore waters and passages. Trade winds will also increase
up to 20 knots across the local waters. Therefore, small crafts
should exercise caution. No small craft advisories are not anticipated
at the moment during the next few days.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 81 92 80 90 / 20 20 20 20
STT 80 91 80 90 / 20 20 20 20

[Gustywind]

Potential Hurricane Scare Early Next Week

30 08 2016

https://anumetservice.wordpress.com/201 ... next-week/


Dale C.S. Destin |

A weather disturbance coming off West Africa will likely cause a scare to residents of the northeast Caribbean early next week. Two of the more reliable weather models are forecasting this disturbance to become tropical storm or hurricane later this week and track in the direction of the islands.

The preliminary forecast track has it moving on a westerly path, in line with the Leeward Islands, which includes Antigua and Barbuda. However, just before reaching the islands, it’s forecast to turn right or north away from the islands, which should spare us its wrath.

ECMWF IFS
ECMWF Integrated Forecast System Showing at least an 80% Chance of a Tropical Cyclone Near the Northeast Caribbean Between Sep 4 and 6

Twenty-one years ago from September 5, 2016, Antigua and Barbuda experienced one of the most powerful hurricanes in its history – Category 4 Hurricane Luis. It brought death and major destruction to the islands. It left in its wake three dead and around US$350 million dollars in damage. It is easily our costliest hurricane in history.

The system that could cause us some stress is not being forecast to be a Luis, God forbid! However, its potential path and timing are reminiscent of Luis. It could be nearest us around September 5, just that this time, it should turn away sooner than Luis did and spare us this time.

The hurricane season runs until November 30. The forecast calls for 15 named storms, 7 hurricanes and 3 major hurricanes. Thus far, there have been seven named storms and three hurricanes, the last one being Gaston. The peak of the hurricane season is around September 10; however, for us, it’s around August 20 and September 3. Become hurricane strong by being prepared!

Follow us via our social media platform and stay updated on the 2016 Atlantic hurricane season. We are available on twitter, facebook, wordpress, instagram, tumblr, and google+. Follow us also for all things weather and climate.

[cycloneye]

A weak area of low pressure, associated with a tropical wave, is
located over the far eastern Atlantic near the Cabo Verde Islands.
Environmental conditions are expected to become a little more
favorable for some gradual development of this system by this
weekend while it moves westward at 15 to 20 mph over the tropical
Atlantic.
* Formation chance through 48 hours...low...near 0 percent
* Formation chance through 5 days...medium...40 percent

[Gustywind]

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
757 PM EDT TUE AUG 30 2016

Tropical wave extends from 10N24W to 20N22W moving W at 15-20 kt.
A 1009 mb low is centered along the wave axis near 16N where
global models indicate a maximum 850 mb relative vorticity. In
addition...the low and vorticity coincide with a 700 mb low and
associated troughing that has emerged off the coast of West
Africa. Isolated moderate convection is from 07N-17N between
16W-22W.

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
556 AM AST WED AUG 31 2016

.SYNOPSIS...
A mid to upper level ridge remains as the dominant weather
feature over the local islands at least until the end of the work
week. A dry air mass with Saharan Dust Particles will continue
over the region through at least tomorrow. Then, another Saharan
Air Layer is expected to reach the islands by Saturday. Between
these pulses of Saharan Dust, a weak tropical wave is expected to
increases somewhat moisture content across the region between
Thursday and Friday. Then, model guidance suggested the arrival
of a strong tropical wave on Sunday or Monday next week.

&&

.DISCUSSION...
Relative fair weather conditions with mostly clear skies and
pleasant temperature, around the upper 70s, prevailed overnight.
The weather conditions will be dominate by a mid to upper level
ridge and a dry air mass with Saharan dust particles, as a result
expect hazy skies with warm and hot temperatures today. Although
afternoon convection should be minimal to none, the limited
moisture over the region in combination with daytime heating and
local effects are expected to produce some convection across
western and interior sections of Puerto Rico.

Moisture content should increase somewhat by Thursday and Friday,
as a week tropical wave brought a patch of tropical moisture to
increase the chance of showers and thunderstorms across the
region each day. Once again, another dry pattern is expected with
the arrival of another SAL on Saturday. For the upcoming week,
both, GFS and ECMWF coincide with a strong tropical wave moving
near the islands of PR and the USVI by Sunday or Monday. Please
stay tuned for further information regarding the progress of this
tropical system.

&&

.AVIATION...
VFR conditions expected across most TAFS sites through the
forecast period. However...very brief periods of MVFR conditions
with mountain obscurations can be expected over TJMZ between
31/18z- 31/22z. Low level winds will be mainly east at 10 to 15
kts.

&&

.MARINE...
Mariners can expect seas between 3 and 5 feet with occasional seas
up to 6 feet. The seas are expected to increase up to 6 feet
across the Caribbean passages tonight, therefore small craft
operators should exercise caution across these areas. Trade winds
will remain up to 20 knots across some of the local waters for the
next couple of days.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 92 81 89 79 / 20 10 20 50
STT 91 80 91 80 / 20 10 20 40

[cycloneye]

A broad area of low pressure, associated with a tropical wave, is
located over the far eastern Atlantic near the Cabo Verde Islands.
This wave is in an environment of very dry air, which should prevent
any significant development for a few days. Some development is
possible over the weekend when the wave nears the Lesser Antilles.
* Formation chance through 48 hours...low...near 0 percent
* Formation chance through 5 days...medium...40 percent

[Gustywind]

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
701 AM EDT WED AUG 31 2016



...TROPICAL WAVES...
A tropical wave extends across the Cabo Verde Islands from 10N26W
to 1010 mb low pressure near 15N25W to 19N24W, moving west at
15-20 kt. The gradient between the low pressure and ridging to the
north is enhancing northeast winds across the eastern Atlantic
north of 15N and east of 30W. The embedded circulation is drawing
rich deep layer moisture northward across the eastern Cabo Verde
Islands, possibly bringing a few showers to the region. The system
is also interning dry Saharan air and dust to the north and west
of the islands, limiting convection.

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
200 PM AST WED AUG 31 2016

.SYNOPSIS...Tutt low will continue to shift farther west of the
region today, while a mid to upper ridge will build and establish
a strong hold across the northeastern Caribbean at least through
Thursday. This pattern will create a fairly strong cap inversion
across the region which should limit convective development across
the islands. Satellite imagery and recent satellite derived aerosol
products suggest the suspended dust in the saharan air layer continued
to diminish across the region. Strong surface high pressure ridge
will build north of the region to maintain a fairly tight pressure
gradient and moderate easterly trade winds through at least Thursday.
A weak easterly perturbation now just east of the Lesser Antilles,
is expected to enter the Eastern Caribbean late Thursday through
early Friday.

&&

.DISCUSSION...Mostly sunny to partly cloudy skies prevailed across
the islands today. So far a few streamer like showers were noted
over areas on the windward side of the U.S Virgin Islands as well
as over portions of Culebra, Vieques and the East interior
sections of Puerto Rico. Most of the showers however were of light
intensity light and of short duration.

During the rest of the afternoon additional diurnally and locally
induced showers may develop over portions of the central and west
interior sections of Puerto Rico with a slight chance of an isolated
thunderstorm. Activity and cloudiness over land will then quickly
diminish during the early evening and overnight, leaving partly
cloudy to mostly clear skies. Data from the recent TJSJ upper air
sounding as well as model guidance all coincide and continued to
suggest decreasing precipitable water values during the next day
or so.

By late Thursday and Friday, the previously mentioned easterly
disturbance is expected to bring a weak surge of moisture across
the region. This in turn will bring instability and increase the
chance for showers and thunderstorm development across the islands
and coastal waters. Thereafter drier air and a Saharan air layer
is forecast to quickly filter in across the region in advance of a
strong tropical wave presently forecast to move across the region.

At this time model guidance have become a bit more consistent and
continue to suggest a strong tropical wave forecast to cross the
Lesser Antilles and arrive across the forecast area late Sunday through
Monday. By then a tutt aloft will shift farther west and ridge will
build aloft once again. This pattern will support favorable conditions
for convective development due to the increasing low level convergence
and instability. Will however continue to monitor and see how condtions
unfold. Stay tuned during the next few days for further information
regarding the progress of this feature.

&&

.AVIATION...Mainly VFR conditions expected across all terminals
through the forecast period. However, shra/-tsra over western PR
impacting mainly TJMZ still possible thru 22z. Low level winds will
continue E-ENE at 15-30 kts. Land breeze variations at the sfc expected
overnight across PR terminals.

&&

.MARINE...Recent data from the surrounding buoys continued to suggest
a slight increase in the easterly trade winds with a slight chop across
the portions of the regional waters. Overall seas were at 5 feet
or less and 15 knots or less at this time. However expect a gradual
increase in winds and seas up to 20 knots and 6 feet or less overnight
through the end of the week. Small crafts should therefore exercise
caution across the coastal waters.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 81 89 79 91 / 10 20 50 50
STT 80 91 80 89 / 10 20 40 40

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
600 AM AST THU SEP 1 2016

.SYNOPSIS...
A mid to upper level ridge will continue to build over the region
today through the weekend. A weak tropical wave is expected to
move across the region late tonight and Friday. A dry air mass
with suspended dust particles is expected through the weekend.
A tropical wave is expected to reach the local islands Sunday or
Monday.

&&

.DISCUSSION...
The Doppler Radar detected limited shower activity overland during
the overnight hours. However a line of showers moved along the
north coastline of Puerto Rico around midnight. For today, under
the prevailing mid to upper level ridge, expect a strong cap
inversion across the region, which should limit afternoon
convection across the islands. However, trade wind showers are
expected from time to time across the islands without any
significant rainfall amounts. Late this afternoon and into
Friday, shower should increase in coverage as the moisture of a
weak tropical wave reach the islands. Therefore, showers and
thunderstorms should increase somewhat on Friday.

A Saharan Air layer is expected to reach the CWA Saturday through
Sunday, to result in hazy skies. But the combination of daytime
heating and local effects could produce some localize afternoon
convection each day across the interior and west PR. A strong
tropical wave is expected to reach the local islands on Sunday or
Monday. If the model guidance are correct, showers and
thunderstorms should increase in coverage and intensity. In
additions, squally weather is possible with this system.

&&

.AVIATION...
Mostly VFR conditions expected across all terminals through the
forecast period. However, shra/-tsra over western PR impacting
mainly TJMZ still possible thru 01/17z-22z. Low level winds will
continue East at 15-30 kts below FL250.

&&

.MARINE...
A slight increase in the easterly trade winds will continue to
produce choppy seas between 4 and 6 feet across most of the local
waters. As a result, small craft operators should exercise caution
across most of the local waters, due to seas between 4 and 6 feet
and winds up to 20 knots.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 89 80 89 81 / 20 40 40 30
STT 91 83 89 83 / 20 40 40 30

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
202 PM AST THU SEP 1 2016

.SYNOPSIS...Showers and thunderstorms will spread over eastern
Puerto Rico this afternoon until early tonight, with activity
during the day tomorrow over the interior portions of the Island.
A strong tropical wave will move through both the U.S. Virgin
Islands and Puerto Rico Sunday night and Monday with thunderstorms
and heavy rain.

At upper levels...A ridge originating from a high to
the north will cross through the area from east to west, followed
by a trough that will cross through Saturday evening. A second,
weaker ridge will move through on Monday evening. After this, flow
from the northeast and then east will set up over the area with a
weak jet.

At mid levels...High pressure is set up across the sub-tropical
Atlantic ocean. That high will continue to our north or northeast
for much of the next 7 days. In our area a weak trough will move
through overnight, a second sunday night with a third late in the
week.

At lower levels...A weak tropical wave will move through the area
overnight. Limited drying will occur afterward, but a more potent
tropical wave will move through Sunday night and Monday morning
with showers and thunderstorms and abundant rain. A good chance of
showers continues until Tuesday, but drier weather is interrupted
again on Wednesday with another band of moisture. Another tropical
wave will move through Friday night.

&&

.DISCUSSION...Showers moved west southwest through the Caribbean
east of Puerto Rico this morning leaving some showers over the
U.S. Virgin Islands. Then during the early afternoon some of them
intensified to produce thunderstorm between Culebra and Vieques
and downstream from Saint Croix. Moisture over the area will peak
tonight but will not diminish tremendously before the best
moisture moves through Sunday night through Tuesday morning. The
latest 01/12z GFS run showed precipitable water values approaching
2.4 inches then. Winds with this system could be gusty as it
enters into the dry Saharan dust laden air ahead of it, but also
models are showing winds around 700 mb around 30 knots some of
which will sink into the lower layers. Current estimates show
that Sunday night`s wave could bring around 3 to 6 inches then
through the subsequent 48 hours. Drying occurs during the day
Tuesday and into Wednesday and then moisture rises quickly again
to almost 2 inches of precipitable water. Rainfall amounts will
be moderate later in the week.

&&

.AVIATION...SHRA/TSRA over western PR will last through at least 22z
impacting mainly TJMZ and the vicinity of TJPS. SHRA/TSRA is
expected to increase from the Caribbean waters this evening through
Friday morning. Therefore, periods of MVFR conditions are possible
at the leeward/USVI terminals. Low level winds will continue at 10-
25 kts from the ENE through at least 02/06z, becoming ESE
afterwards.

&&

.MARINE...Winds and seas have been a little agitated around the
local coasts, but overall winds were around 12 to 16 knots and
seas up to 5 feet. Small craft advisories may be necessary Sunday
night or Monday when the next strong tropical wave moves through.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 80 89 79 89 / 40 40 30 30
STT 80 89 81 91 / 50 50 30 30

&&

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
504 AM AST FRI SEP 2 2016

.SYNOPSIS...A mid level ridge will continue to prevail across
the forecast area through early next week. A drier air mass is
expected to encompass the local islands later today, as a surface
disturbance continues to move away. The next tropical wave passage
is expected late Sunday and into Monday.

&&

.DISCUSSION...Variably cloudy skies prevailed overnight and early
this morning across the local islands. Showers and a few isolated
thunderstorms were observed across the local waters with a few of
them affecting eastern and northern Puerto Rico as well as portions
of the U.S. Virgin Islands. These showers and isolated thunderstorms
were associated with a passing surface disturbance. As the surface
disturbance moves away from the local islands later today, a
drier air mass is expected to encompass the forecast area with
precipitable water values below the normal range. However, still
expect showers and thunderstorms across NW PR as well as portions
of the San Juan Metro area this afternoon.

Under the aforementioned mid level ridge, moderate easterly winds
and limited low level moisture, a mainly fair weather pattern
will prevail tonight through early Sunday with locally induced
afternoon showers and thunderstorms across west and southwest
Puerto Rico.

Although the bulk of moisture associated with the next tropical
wave is expected to remain over the Caribbean waters, a sharp
increase in moisture is still expected across the local islands
Sunday afternoon with lingering moisture prevailing through early
Tuesday morning. Winds also expected to increase with the tropical
wave passage. As a result, expect wetter conditions late Sunday
and Monday with squally weather possible.

&&

.AVIATION...Mostly VFR conditions expected with vicinity SHRA
possible across the USVI, Leeward Islands and Eastern PR terminals.
After 02/17Z, SHRA/TSRA expected to develop across western and
interior Puerto Rico, affecting the vicinity of TJBQ and TJMZ
through 02/22Z with mountain top obscuration. In addition, VCSH/VCTS
are possible at TJSJ btwn 02/15-19z. Sfc winds expected from the E-
ESE below 10 kt til 02/13z, increasing to 15-20 kts with higher
gusts after 02/13Z.

&&

.MARINE...Winds of 10-20 knots and seas of 3-5 feet expected today.
Winds and seas will likely increase Sunday into Monday as the
tropical wave approaches the local waters. Seas will likely build
to 6-8 feet on Monday.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 90 79 89 79 / 30 30 30 30
STT 91 80 91 80 / 50 30 30 30

[cycloneye]

2 PM TWO:

A tropical wave over the central tropical Atlantic Ocean located
about 1000 miles east of the Lesser Antilles is producing only
disorganized showers and thunderstorms. Development of this system,
if any, will be slow to occur while it approaches the Lesser
Antilles and continues westward into the eastern Caribbean Sea early
next week.
* Formation chance through 48 hours...low...10 percent
* Formation chance through 5 days...low...20 percent