Caribbean - Central America Weather

[cycloneye]

Is that Tropical Wave for Saturday on the West coast of Africa now,ready to leave?

I think so.If that is the case it will be a fast mover.

Looking more closely to GFS model,is the wave now around 25W.

[HurricaneFan]

Well there is a run of the GFS posted in The Tropical Wave at 35W thread about a Wave reaching the Lesser Antilles on Thursday coming.It looks a little bit earlier than this forecast is saying,yet there is no Tropical Wave(the one at 25W) following behind it.
So could it be the Wave at 35W instead?

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
155 PM AST SUN AUG 7 2016

.SYNOPSIS...Surface high pressure to the north of the local
islands will remain in place through tuesday before being replaced
by a stronger surface high further north just east of the
northeastern U.S. Upper high over the area will move away and an
upper low will move through the local islands on Tuesday through
Wednesday as it moves west, then weaken late in the week when it
is west of Hispaniola. The expected weather this week will likely
be locally induced with the exception of maybe Wednesday as the
upper low passes through. The next tropical wave with a decent
increase in moisture is expected to approach the local area by
next weekend.


&&

.DISCUSSION...A fair weather morning and early afternoon was
observed across the local forecast area under an ESE wind flow.
Cloudiness has gradually increased through the day but no rain has
been observed, however the Northwest quadrant of PR appears to
have denser clouds due to the help of the sea breeze convergence,
this area may experience some showers in the mid to late afternoon
hours. Satellite imagery also indicates streamers coming off the
USVI and El Yunque rainforest, but no rain from those streamers
yet. The daytime max temp in San Juan thus far is 92 degrees,
which ties the old record set back in 1995. The max temps at St.
Thomas and St Croix so far today has been 90 degrees.

The available moisture is steadily decreasing today. A brief
patch of moisture is expected on Monday but there will also be a
slight increase in Saharan dust particles which will linger
through Tuesday into early Wednesday. An upper low is expected to
move through the local area on Wednesday into Thursday, which may
cause an increase in shower activity on Wednesday, but we mainly
expect brief showers in the morning across eastern PR and the
outlying islands then showers and thunderstorms in the afternoon
across W-NW PR. Locally induced showers and thunderstorms are
possible late this week and then moisture increases with a
tropical wave next weekend, which is expected to cause an increase
in overall shower and thunderstorm activity.

&&

.AVIATION...Prevailing VFR conditions durg prd. Few -SHRA/SHRA btw E
PR and Nrn Leeward Islands. SCT-BKN Clds FL025... FL050. FEW TOPS
FL120-FL180. SHRA/ISOLD TSRA psbl across the interior and vcty of
TJBQ/TJMZ...bcmg mostly clr with only Few clds blo FL060 aft 07/22z.
Wnd fm SE blo FL300 15-20kts. SFC wnd mainly fm SE around 10-15
kts...bcmg lgt/vrb aft 08/00z.


&&

.MARINE...Moderate risk of rip currents across many of the local
beaches. Small craft should exercise caution across the Atlantic
waters as winds could reach 20 knots and seas up to 6 feet across
the offshore Atlantic. Elsewhere, seas between 2-5 feet expected
today and tonight.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 82 90 80 89 / 30 30 20 20
STT 81 90 80 90 / 30 30 20 20

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
519 AM AST MON AUG 8 2016

.SYNOPSIS...
A surface high pressure to the north of the local islands will
remain in place until tomorrow. Then another surface high
pressure will move across the Western Atlantic and into the
Central Atlantic. At upper levels, a mid-upper high will continue
over the area until Tuesday. As this high moves westward, an
upper low is forecast to amplify over the islands between Tuesday
and Wednesday. Then, the upper level low is expected to move over
Hispanola by Thursday. At this time, another strong tropical wave
is forecast to approach the local area by the upcoming weekend.

&&

.DISCUSSION...
Limited shower activity was detected with the Doppler radar
overnight. Most of the activity was observed across the local
Caribbean Waters. Satellite imagery suggested low moisture
concentration across the region, this will result in mostly sunny
to partly cloudy skies with little or no shower activity today.
However, the available moisture in combination with the diurnal
heating and local effects will induce some showers and maybe one
or two thunderstorms across the west and central sections of
Puerto Rico during the afternoon. In addition, hazy skies are
likely today and Tuesday, as model guidance and satellite products
suggest the arrival of Saharan Dust Particles during these days.
Also, warm and hot days are likely, with maximum coastal
temperatures ranging between the low and mid 90s.

An upper low is expected to move through the local area on
Wednesday into Thursday, which may cause an increase in shower and
thunderstorm activity, but the limiting factor will be the
available moisture, which is forecast to remain low. The next
tropical wave will reach the region by the upcoming weekend,
increasing the moisture content, to enhance shower and
thunderstorm activity.

&&

.AVIATION...
VFR conditions to prevail across all TAF sites...except
after around 08/17z in western PR where isolated MVFR conditions
with mountain obscurations can be expected. Low level winds will
be mainly SE at 10 to 15 kts with higher gusts.

&&

.MARINE...
Moderate risk of rip currents remains across many of the local
beaches. During the afternoon hours, small craft operators should
exercise caution across the Northern coastal waters of Puerto Rico
due to winds up to 20 knots. Elsewhere, mariners can expect seas
up to 5 feet and winds around 15 knots.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 91 81 90 79 / 30 30 30 30
STT 90 82 90 79 / 30 30 30 20

[HurricaneFan]

The 06Z GFS shows this Tropical Wave coming from far south,then moving NW,then NNW,then NW again.
Isn't that quite strange considering the steering pattern we've had this season so far?

[cycloneye]

The 06Z GFS shows this Tropical Wave coming from far south,then moving NW,then NNW,then NW again.
Isn't that quite strange considering the steering pattern we've had this season so far?

It will be interesting to see if it pans out that way.

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
129 PM AST MON AUG 8 2016

.SYNOPSIS...Mid to upper level ridge aloft will gradually shift
farther west by late Tuesday as Tutt low is forecast to move over
the Northeast caribbean and cross the area reaching the Mona passage
by Wednesday. This will be supported by a tutt induced low level
trough which will move across the local area on Wednesday and
Thursday. Surface ridge is to slowly shift westward across the
Atlantic over the next few days,while a weak surface trough
approaches from the East.

&&

.DISCUSSION...Mostly fair weather skies can be expected for the
next several days as no significant weather feature or moisture
advection is forecast. However, expect periods of passing early
morning showers along portions of the coastal waters and east
sections of the islands, followed by isolated to scattered shower
development mainly over the central interior and west section of
Puerto Rico. By Wednesday, winds are forecast to to become more
northeasterly, as the surface trough crosses the area. No significant
moisture is expected to accompany this feature, however the mid to
upper level trough should briefly destabilize the local atmosphere
thus increasing the chance for locally and diurnally induced
afternoon convection.

Next tropical wave still forecast to approach and move across the
region by late Friday and into the next weekend. By then, models
suggest increasing moisture convergence and instability with better
potential for showers and isolated thunderstorms development across
the forecast areas once again.

&&

.AVIATION...Mainly VFR conditions expected to prevail across all
terminals. However, -SHRA/TSRA could still develop across western PR
thru 22z. Light passing showers in trade winds could briefly affect
the USVI/Eastern PR terminals overnight into early Tuesday morning.
On Tuesday afternoon, SHRA/TSRA expected to develop over the interior/west
sections of PR, impacting mainly TJMZ and TJPS as wind turn more E-ENE
by noon tomorrow. Sfc winds overnight light and variable, increasing
from the east at 10-15 knots after 09/12z with sea breeze variations
after 09/14z.

&&

.MARINE...Recent buoy data surrounding most of the coastal waters
continued to suggest seas of less than 4 feet and easterly winds
between 10-15 knots. Small craft operators should however continue
to exercise mainly across the local Atlantic waters due to slight
wind chop with possible seas up to 6 feet and east winds up to 20
knots.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 81 90 79 90 / 30 20 30 30
STT 82 90 79 89 / 30 30 20 20

&&

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
547 AM AST TUE AUG 9 2016

.SYNOPSIS...At upper levels, a TUTT low will move over the area
today, then will continue it path across the Hispaniola and over
the Bahamas between Thursday and Friday. At mid levels, a tropical
wave with plenty of moisture is forecast to move across the local
area by Saturday. At the surface, a high pressure to the north of
the local islands will remain in place until tonight. Then another
surface high pressure will move across the Western Atlantic and
into the Central Atlantic.

&&

.DISCUSSION...
A surge of moisture moved across the islands, as a result the
Doppler radar detected an increment in passing showers overnight.
Although moderate passing showers were detected from time to time
over land, the rainfall accumulations were not significant. For
this morning, expect some passing showers mainly over the waters
and the windward sections of PR and the USVI. Then during the
afternoon, the proximity of a TUTT Low, and the available moisture
will combine with diurnal effects to produce showers and
thunderstorms, mainly over the interior and southwestern sections
of PR. In addition, streamers could form off the USVI and La
Sierra de Luquillo to create periods of moderate to locally heavy
showers near those areas. Also, another day with temperatures
around the low 90s is possible today.

Model guidance continues to forecast the arrival of a tropical
wave with plenty of moisture by the Saturday. If it is correct,
moisture convergence and atmospheric instability could enhance the
potential for showers and thunderstorms across the islands,
increasing the potential for flooding across the region.

&&

.AVIATION...
Mainly VFR conditions expected to prevail across the local flying
area. Light passing showers in trade winds could briefly affect
the USVI/Eastern PR terminals this morning. After 9/17Z, SHRA/TSRA
expected to develop over the interior/west sections of PR,
impacting mainly TJBQ and TJMZ. Surface winds will be from the
east at 10-15 knots after 09/12z with sea breeze variations after
09/14z.

&&

.MARINE...
The local buoy network continues to indicate a small northeasterly
swell across the Atlantic Ocean and Caribbean passages. It is
forecast to stay across these sections at least until Wednesday.
However, mariners can expect seas below 5 feet and winds below 18
knots. On the other hand, beach goers can expect a moderate risk
of rip currents across many of the local beaches. A tropical wave
is forecast to deteriorate the weather conditions by Saturday.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 90 79 90 80 / 20 30 30 20
STT 91 79 89 79 / 30 30 30 20

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
148 PM AST TUE AUG 9 2016

.SYNOPSIS...Moderate trade winds will continue throughout the
period as the ridge and high pressure at the surface remain north
of 30 north. The next tropical wave will move through the
Caribbean south of the area but close enough to increase showers
and thunderstorms Saturday.

At upper levels...Weak low pressure east of the area will move
across Puerto Rico overnight. Weak high pressure will move through
overnight on Friday. A second low will pass north of the area
Tuesday of next week.

At mid levels...Weak troughs will move through on Wednesday and
the following Monday. The tropical wave expected on Saturday shows
up poorly at mid levels despite the marked increase in moisture
then at most levels.

At lower levels...The axis of the ridge extending out of the
Azores high pressure will remain at or north of 30 degrees north
latitude through Wednesday of next week to maintain moderate
trade wind flow from the east over the local area. Although a few
weak troughs move through Wednesday, and Friday night strong
features are not apparent during the next 10 days.

&&

.DISCUSSION...The first thunderstorms of the day were seen in the
Leeward Islands, followed by one late morning in a streamer off
of Saint Croix. After noon, thunderstorms developed offshore from
southwest Puerto Rico with tops as high as 40 kft. This area of
activity appears to be owed to a mid to upper level band of
moisture seen mainly in the water vapor product being pulled
southeast over the area by the low that will migrate through the
U.S. Virgin Islands and Puerto Rico tonight. This band is already
in the process of leaving the area and the showers on the
southeast side of the low may be left in the lesser Antilles as
the area of formation there actually appears to be moving
southeast. The GFS show drier air in place today with increasing
stability tomorrow, Wednesday. Therefore we are continuing with
the forecast inherited which has less shower probability than for
today.

The latest iteration of the GFS at 09/12Z shows moisture at low to
mid levels increasing considerably south of the area beginning
Thursday. But only by Saturday does it show the last lobe of this
moisture moving through the local area. It is followed by
considerably drier air Sunday and Monday. Nevertheless, after an
active day Saturday area-wide, would expect some showers and
thunderstorms to form in the west portion of Puerto Rico each
afternoon.

For the U.S. Virgin Islands, significant rainfall is not expected
except for the tropical wave that moves through on Saturday, and
even then, current indications are that moisture will not be
sufficient for flooding there.

&&

.AVIATION...SHRA/TSRA expected to continue across the SW quadrant of
PR thru 22z, impacting mainly the flying area of JPS/JMZ. Elsewhere
VFR conditions expected to prevail. Passing showers could briefly
affect the USVI/Eastern PR terminals overnight into early Wednesday
morning. Sfc winds overnight light and variable, increasing from the
east-southeast at 10-15 knots after 10/12z with sea breeze
variations after 10/14z. Maximum winds north near FL330 at 39 kts
in 09/12z SJU sounding.

&&

.MARINE...Moderate trade winds generally from the east are
expected to prevail. Small craft advisories are not expected
during the next 10 days. Small craft may need to exercise caution
when the wave moves through on Saturday.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 80 90 79 91 / 30 30 20 20
STT 82 89 81 91 / 30 30 20 20

[cycloneye]

Area Forecast Discussion...CORRECTED
National Weather Service San Juan PR
530 AM AST WED AUG 10 2016

.SYNOPSIS...An upper level trough across the eastern Caribbean
will continue to shift west during the next few days. As this
feature moves west, a short wave ridge will build in from the
east. Ridge aloft will hold over the forecast area Friday through
at least the upcoming weekend. A low level disturbance will
continue to move across the local islands today. The next tropical
wave is forecast to move across the eastern Caribbean Saturday.

&&

.DISCUSSION...Partly cloudy skies prevailed across the local
islands overnight and early this morning. Passing showers were
noted across the coastal waters...with some of them affecting the
U.S. Virgin Islands as well as the eastern half of Puerto Rico.
Minimum temperatures were in the upper 70s to low 80s and the
winds were generally from the east at 10 mph or less.

Passing showers and isolated thunderstorms possible will continue
to prevail across the U.S. Virgin Islands as well as eastern
Puerto Rico throughout the day as an induced low level disturbance
combined with an upper level trough moves across the area. This
will also result in shower and thunder development over and north
of the Cordillera Central late this morning and afternoon,
including portions of the San Juan Metro Area. A decreasing trend
in available moisture is expected across the forecast area as soon
as tonight and continue through Friday. Although limited available
moisture will prevail Thu-Fri, locally induced afternoon showers
and thunderstorms are still expected each day. The chance for
shower and thunder activity will improve during the weekend as a
tropical wave enters the forecast area.

&&

.AVIATION...VFR conditions expected to prevail thru 10/16Z with
brief SHRA over the local islands causing VCSH. SHRA/TSRA...mainly
across W-PR after 10/16Z likely affecting TJMZ and TJBQ.
Therefore...MVFR conds are possible possible and possibly VCTS at
TJSJ between 18Z-22Z. Sfc winds will be from the East at 10-15 kt
shifting to the ESE around 10/18Z with sea breeze variations.

&&

.MARINE...Seas up to 5 feet and winds up to 20 knots are expected
today across the regional waters. Small craft are urged to exercise
caution across the Atlc coastal waters. A small northeasterly swell
will continue to affect the local waters today. The next tropical
wave is forecast to move across the local waters Saturday.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 90 79 90 80 / 40 30 30 20
STT 91 80 91 81 / 40 20 20 20

&&

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
153 PM AST WED AUG 10 2016

.SYNOPSIS...An upper level low that is spreading showers over the
area will continue to move west northwest with drier air
following. Showers will diminish during the rest of the week
until a tropical wave passage Saturday and Sunday. Better drying
will follow that.

At upper levels...An upper level low over southwest Puerto Rico
will move toward the Bahama Islands through Friday. High pressure
will follow over the weekend. Divergence aloft will increase with
the wave passage over the weekend. Another low will pass north of
Puerto Rico and the U.S. Virgin Islands Monday night.

At mid levels...After the trough over the local area moves away
tonight another trough will move through the area over the
weekend. High pressure will continue to dominate the sub tropical
Atlantic through the next 10 days. Mid levels are mostly dry with
very modest moisture accompanying the wave passage over the
weekend.

At lower levels...High pressure at the surface extending across
the Atlantic ocean from beyond the Azores will re-form over the
Azores Sunday and move into the central Atlantic next week. This
will hold moderate to fresh trade winds over the local area
through the next 10 days. A tropical wave will move across the
area on Saturday with some moisture following on Sunday. Then
high pressure will fill in north of the area next week in the sub
tropical Atlantic.

&&

.DISCUSSION...Showers and a few thunderstorms moved across the
area with rain over much of the eastern half of Puerto Rico and
some of the Atlantic and Caribbean waters around it. Showers were
also beginning to favor west and northwest Puerto Rico. These
showers are still forming as a result of a band of moisture
spiraling into the upper level low that is now moving off of
Puerto Rico to the west northwest. Tops of the convection have
been as high as 51 kft, but lightning has been strangely sparse.
Activity is expected to taper off very slowly beginning at
sundown. Some showers will linger in the area in the good
moisture that is forecast by the GFS to persist even beyond
tomorrow. The upper level low that has favored shower formation
will have moved west northwest and this should allow a gradual
decrease in shower and thunderstorm activity through Friday night.
Then moisture will have already begun to increase ahead of a
tropical wave. The GFS continues to leave the best moisture to the
south. It is also starting to delay the passage of the best
moisture over the area until after Sunday at 00Z. There should
still be enough favorable dynamics in the area to generate
numerous showers and isolated to scattered thunderstorms Saturday
and diminishing showers on Sunday. At this time any flooding would
be localized to urban and small stream flooding. Conditions
improve early next week.

&&

.AVIATION...SHRA/TSRA will continue mainly across the
interior, north and western sections of PR thru 22z, affecting
mainly TJMZ/TJBQ/TJSJ. MVFR conds, lightning and brief gusty
winds are possible. Low level winds will continue ESE at 8-18 kts.
Light and variable winds overnight at the sfc. VFR elsewhere.

&&

.MARINE...Winds had been flirting with 18 knots in the local inner
waters. But conditions should slowly improve through Friday. At
this time it does not appear that the wave passage over the
weekend will generate small craft advisories.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 79 88 80 90 / 50 20 20 20
STT 80 90 81 90 / 30 10 20 20

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
515 AM AST THU AUG 11 2016

.SYNOPSIS...Weak upper level ridge will build across the forecast
area from the east as a trough aloft continues to shift west.
Ridge aloft will then hold over the forecast area Friday through
at least the upcoming weekend. As this feature moves away, another
upper level trough will establish across the area early next week.
Next tropical wave is forecast to move across the eastern
Caribbean Saturday.

&&

.DISCUSSION...Although trough aloft will continue to move away
from the local islands today, the proximity of this feature
combined with available low level moisture will result in passing
showers across the U.S. Virgin Islands as well as eastern Puerto
Rico in the morning, followed by shower and thunderstorm
development over and north of the Cordillera Central late this
morning and afternoon. Somewhat drier weather conditions are
expected across the area on Friday under the upper level ridge
and associated cap. However, the available moisture across the
area will combine with local effect and diurnal heating to result
in showers and a few thunderstorms in the afternoon hours mainly
across W PR.

Latest guidance suggests precipitable water across the local islands
near the normal values with the best moisture advection remaining
across the Caribbean waters. At this time, the highest chance for
shower and thunderstorm activity is still expected Saturday afternoon
through Sunday morning as a tropical wave and its associated
moisture reaches the local islands. This will bring precipitable
water to above normal values. As this wave moves away Sunday night,
a drier air mass will encompass the local islands with a fair
weather pattern expected Mon-Wed.

&&

.AVIATION...VFR conditions expected to prevail through 11/16Z with
brief SHRA over the local islands causing VCSH. SHRA/TSRA...mainly
across W-PR after 11/16Z likely to affect TJMZ causing MVFR conds.
VCTS expected at TJBQ and possible at TJPS and TJSJ. Sfc winds will
be from the East at 10-15 kt and gusty, shifting to the ENE after
11/18Z with sea breeze variations.

&&

.MARINE...Seas up to 5 feet and winds up to 15 knots are expected
today across the regional waters. A surface high pressure north of
the region will continue to promote moderate easterly winds during
the next few days. Winds will become east southeast the upcoming
weekend as the high pressure shifts into the northeastern atlantic
and a tropical wave moves across the local waters. As this wave
moves across the area, shower and thunder activity will increase
mainly across the Caribbean waters.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 89 80 90 79 / 30 20 20 20
STT 91 80 91 79 / 20 20 20 30

[cycloneye]

 https://twitter.com/anumetservice/status/763761565120081920

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
123 PM AST THU AUG 11 2016


.SYNOPSIS...TUTT LOW WILL CONTINUE TO MOVE WEST AND EXIT THE AREA BY
THIS EVENING AS UPPER LEVEL RIDGE BUILDS FROM THE EAST AND HOLDS
THRU THE WEEKEND. ANOTHER TUTT WILL ESTABLISH ACROSS THE AREA FROM
THE EAST BY EARLY NEXT WEEK. A TROPICAL WAVE WILL MOVE MAINLY ACROSS
THE OFFSHORE CARIBBEAN WATERS ON SATURDAY. WEAK SAL EXPECTED SUNDAY-
MONDAY.


&&

.DISCUSSION...SUNNY TO PARTLY CLOUDY SKIES WERE OBSERVED DURING
THE MORNING HOURS TODAY ACROSS THE FORECAST AREA. STREAMERS
DEVELOPED OFF THE USVI LEAVING MINOR RAINFALL ACCUMULATIONS OVER
PARTS OF THE ISLANDS. AFTERNOON SHOWERS AND THUNDERSTORMS DEVELOPED
OVER THE INTERIOR AND WESTERN SECTIONS OF PUERTO RICO. AFTERNOON
CONVECTION WAS ENHANCED BY THE TUTT OVER THE HISPANIOLA. ALSO, THE
SAN JUAN STREAMER CREATED SHOWERS EARLY IN THE AFTERNOON HOURS
ACROSS BAYAMON, GUAYNABO AND SAN JUAN. THIS ACTIVITY ACROSS
MAINLAND PR SHOULD DIMINISH BY SUNSET. DRIER AIR FILLS IN LATER
TONIGHT FROM THE EAST, LIMITING SHOWERS ACROSS THE FORECAST AREA.

UPPER LEVEL RIDGE MOVING FROM THE EAST WILL REPLACE TUTT AND PROMOTE
CAP INVERSION OVER THE ISLANDS. TROPICAL WAVE IS EXPECTED TO MOVE
MAINLY OVER THE OFFSHORE CARIBBEAN WATERS BETWEEN LATE FRIDAY AND
SATURDAY. THIS WILL PROMOTE THE DEVELOPMENT OF SHOWERS AND
WITH GUSTY WINDS, BUT MAINLY OVER THE CARIBBEAN COASTAL
WATERS OF THE ISLANDS. AFTERNOON SHOWERS AND THUNDERSTORMS ARE
EXPECTED MAINLY OVER AND TO THE NW OF THE CORDILLERA CENTRAL AS
WINDS SHIFTS MORE FROM THE SOUTHEAST. AS NEW TUTT MOVES OVER THE
ISLANDS BY EARLY NEXT WEEK, THE LIMITED MOISTURE COMBINED WITH
DIURNAL EFFECTS WILL BE ENOUGH TO INDUCE AFTERNOON CONVECTION OVER
THE WESTERN AREAS OF PR WITH ENHANCEMENT OF THE TUTT. SOME HAZY
SKIES ARE POSSIBLE LATE SUNDAY THRU MONDAY AS SAL MOVES ACROSS THE
FORECAST AREA.

&&

.AVIATION...SHRA/TSRA, mainly across W-PR likely to affect TJMZ
causing MVFR conds through at least 22z. VCTS expected at TJBQ.
Sfc winds will be from the East at 10-15 kt and gusty, with sea
breeze variations. Winds shifting from east to south at FL180.
Maximum wind south 42 knots at FL370.


&&

.MARINE...SEAS SHOULD REMAIN BELOW SMALL CRAFT ADVISORY CRITERIA
DURING THE NEXT SEVERAL DAYS. SEAS WILL RANGE BETWEEN 3-5 FEET AND
WINDS WILL CONTINUE FROM THE EAST AT 10-15 KNOTS AND LOCALLY HIGHER
DUE TO SEA BREEZE VARIATIONS. WINDS SHIFT MORE FROM THE SOUTHEAST
DURING THE WEEKEND AS TROPICAL WAVE MOVES ACROSS THE AREA AND A
SURFACE HIGH PRESSURE SHIFTS FURTHER TO THE NORTHEAST ACROSS THE
ATLANTIC.


&&


.PRELIMINARY POINT TEMPS/POPS...
SJU 80 90 79 89 / 20 20 20 60
STT 80 91 79 87 / 20 20 30 50

&&

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
500 AM AST FRI AUG 12 2016

.SYNOPSIS...Ridge aloft will continue to build across the
forecast area today and hold through at least early Sunday. As
this feature moves away early next week, another upper level
trough will establish across the area. Next tropical wave is
forecast to move across the eastern Caribbean Saturday.

&&

.DISCUSSION...Partly to variably cloudy skies with a few passing
showers were observed during the overnight and early morning hours
across the local area. Most of the showers were over the waters
but some of them affected land areas leaving minimal accumulations.
The overnight minimum temperatures were in the mid to upper 70s
across the lower elevations and in the mid to upper 60s across the
higher elevations.

An upper level trough north of Hispaniola will continue to pull
moisture across the eastern Caribbean with the best moisture
advection remaining across the Caribbean waters and south of the
local islands. Over the islands, precipitable water is expected
to be near normal values through at least Saturday afternoon.
Although the building ridge will prevail today, there is enough
moisture to combine with local effects and diurnal heating to
result in shower and thunderstorm development across the southwest
quadrant of Puerto Rico late this morning and afternoon.

Environmental conditions are expected to become favorable for
convection as a tropical wave moves across the area Saturday. The
highest chance for shower and isolated thunder activity at this
time is expected mainly across the Caribbean waters...USVI and E
PR in the late morning hours, spreading across W and NW PR in the
afternoon. Moisture associated with this wave will prevail through
at least Sunday morning. As this wave moves away, a drier air mass
will encompass the local islands Sunday afternoon with a fair
weather pattern expected Sunday afternoon thru Wednesday. Some
hazy skies are possible late Sunday thru Monday as SAL reaches the
forecast area.

&&

.AVIATION...VFR conditions expected to prevail through 12/16Z with
brief SHRA over the local islands causing VCSH. SHRA/TSRA...mainly
across W-PR after 11/16Z likely to affect TJMZ causing MVFR conds.
VCTS expected at TJBQ and possible at TJPS and TJSJ. Sfc winds will
be from the East at 10-15 kt and gusty, shifting to the ENE after
12/18Z with sea breeze variations.

&&

.MARINE...Seas continued at 4 feet or less and winds from the
east at 15 knots. Tropical wave still expected to move across the
Regional waters over the upcoming weekend and this will bring a
slight increase in local winds and seas.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 89 79 88 80 / 20 20 60 40
STT 90 79 89 80 / 20 30 50 40

&&

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
159 PM AST FRI AUG 12 2016

.SYNOPSIS...Ridge aloft will hold through the weekend across the
forecast. An upper level trough will then establish across the
area by early next week. Tropical wave will continue to move
across the Caribbean Sea through late Saturday. Surface high
pressure across the Atlantic will continue to promote moderate
easterlies through next week. Weak SAL will fill in by
Sunday/Monday.

&&

.DISCUSSION...Showers and isolated thunderstorms are expected to
continue and develop over the interior/southwestern sections of PR
through sunset. It remained mostly sunny to partly cloudy across
the rest of the area with some streamers developing across the
USVI. Tropical wave across the eastern Caribbean will increase
shower and thunderstorms across the Caribbean waters with some
reaching coastal areas south of the islands through the overnight
hours into Saturday morning. On Saturday, as upper ridge support
a CAP and as steering winds turn more SE, best convection should
focus over the NW quadrant of the island. Weak SAL event is
expected between Sunday and Monday, then upper level trough moves
from the east...with only enhancing afternoon convection through
much of early next week across western PR.


&&

.AVIATION...SHRA/TSRA...mainly across W-PR will affect TJMZ, and
possibly TJBQ, causing periods of MVFR conds. Sfc winds will be from
the East at 10-15 kt and gusty, with sea breeze variations. East
flow 15 to 25 kt up to FL220 shifting to south by FL300 and
increasing to 40 kt by FL420. South winds will diminish considerably
to less than 20 kt by 13/12z.


&&

.MARINE...Seas should continue between 3-5 feet and winds expected
to continue 10-17 knots from the east, with an east-southeast
component through the weekend.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 79 88 80 87 / 20 60 40 30
STT 79 89 80 90 / 30 50 40 20

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
427 AM AST SAT AUG 13 2016

.SYNOPSIS...Tropical wave expected to affect the local islands
today, bringing an increase in overall moisture as well as an
increase in shower and thunderstorm activity starting from the
early morning hours. Surface high pressure across the eastern
Atlantic will promote easterly winds through the weekend before a
surface high pressure develops across the western Atlantic early
in the upcoming workweek but continuing to promote easterly winds.
Upper low over the Bahamas will continue to move west wile another
upper low to the northeast of the leeward islands moves west and
passes just north of the local islands early next week.

&&

.DISCUSSION...Showers and isolated thunderstorms associated with
the approaching tropical wave are already being detected by the
doppler radar at this hour. Mostly over the Caribbean waters and
around Saint Croix so far but this activity is expected to
continue moving west to west northwest and affect the rest of the
local waters and islands as the day progresses. Showers will start
affecting the USVI as well as Vieques and Culebra very early in
the morning then gradually affect eastern PR. These morning
showers are expected to be passing showers but the number of
showers that are present will keep some areas with locally
numerous showers. As the day heats up the cloudiness and shower
activity is expected to start migrating west northwest over PR,
eventually causing numerous showers and scattered thunderstorms
across the interior, north, and west sections of PR. Some of
these showers and thunderstorms could cause urban and small stream
flooding.

Drier air is expected to move in on Sunday, which means that
mainly locally induced showers and thunderstorms are expected on
Sunday afternoon across the northwestern quadrant of PR. Saharan
Dust will move in on Monday into Tuesday, which could limit the
shower activity and thunderstorm development over the local
islands. However, it is still possible to have thunderstorms in
the afternoon across western PR.

Other than locally induced showers and thunderstorms, none of the
long range models have anything moving in that would cause
exceptional amounts of rain through this upcoming week with the
exception of a small area of moisture that is expected to move in
on Thursday.

&&

.AVIATION...Periods of MVFR or even IFR will remain possible at the
USVI as well as PR terminals through the day as a tropical
wave/easterly disturbance moves across the eastern Caribbean.
SHRA/TSRA in and around IST/ISX and JSJ in the morning, spreading
across W PR in the afternoon. Low level winds will be from the E to
SE at 15-20 kt but higher in TSRA. Prevailing VFR at the leeward
terminals.

&&

.MARINE...Seas of 2 to 4 feet expected today and tonight with
winds generally 17 knots or less. There is a moderate risk of rip
currents across NW-PR, NE-Culebra and E-St. Croix. Showers and
thunderstorms across the local waters could be hazardous as it
could have occasional lightning, gusty winds, and heavy rain.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 89 78 90 79 / 60 30 30 10
STT 89 79 89 79 / 60 50 50 20

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
156 PM AST SAT AUG 13 2016

.SYNOPSIS...Tropical wave will move away from the area tonight. A
dry airmass will encompass the region late tonight into Sunday.

&&

.DISCUSSION...Scattered to numerous showers affected the local
area this morning and early this afternoon. Early this morning..an
area of showers with thunderstorms affected the eastern interior
section of Puerto Rico..with rainfall accumulation up to 1 inch in
some localized areas. Early this afternoon...some showers with
thunderstorms developed over the western interior and northwest
sections of Puerto Rico. This activity was associated with a
Tropical wave...which was moving mainly south of the local area.

For tonight into Sunday...a drier airmass will move across the
region. Saharan air layer will also affect the region...which will
inhibit the chance for showers across the region for the beginningof
the week. However...available moisture will combined with daytime
heating and local effect to produce some showers and a couple of
thunderstorms each afternoon mainly over the western interior
section of Puerto Rico. At this time...no significant weather
events are expected to affect the local region in the long term.

&&

.AVIATION...Brief periods of MVFR conditions will remain possible at
the USVI as well as PR terminals through the rest of the afternoon.
SHRA/TSRA will continue in and around TJBQ causing MFR or even IFR
conditions until 13/22Z. Low level winds will be from the E to SE at
15-20 kt but higher in TSRA. Prevailing VFR at the leeward
terminals.

&&

.MARINE...Seas up to 4 feet and winds up to 15 knots are expected.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 78 90 79 91 / 20 20 10 10
STT 79 89 79 90 / 20 20 20 20

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
453 AM AST SUN AUG 14 2016

.SYNOPSIS...Lingering moisture will cause isolated to scattered
showers to continue across the local area through the morning
hours, then showers and thunderstorms expected to develop across
the western sections of PR. Surface high pressure across the
eastern Atlantic will promote easterly winds through the weekend
before a surface high pressure develops across the western
Atlantic early in the upcoming workweek but continuing to promote
easterly winds. Upper low to the northeast of the leeward islands
will move west and pass just north of the local islands on Monday.

&&

.DISCUSSION...Lingering moisture is causing showers across the
local area. These morning showers are expected to be brief but in
some areas, especially eastern PR, showers could be locally
scattered and that area has already had some good accumulations
with over a quarter of an inch of rain in some areas during the
overnight hours. As the day heats up, the cloudiness and shower
activity is expected to start increasing this afternoon,
eventually causing numerous showers and scattered thunderstorms
across the interior, north, and west sections of PR. Some of these
showers and thunderstorms could cause urban and small stream
flooding.

Drier air is expected to move in on Monday through Wednesday,
which means that mainly locally induced showers and thunderstorms
are expected. Saharan Dust will move in on Monday into Tuesday,
which could limit the shower activity and thunderstorm development
over the local islands. However, it is still possible to have
thunderstorms in the afternoon across western PR.

Latest guidance suggests that a tropical wave will be approaching
the local islands by Thursday. This tropical wave should bring
good moisture and the activity of showers and thunderstorms may
increase once again. Drier air returning to the area on Friday.

&&

.AVIATION...VFR conds expected to prevail at all TAF sites through
14/16z with -SHRA in and around JSJ/IST and ISX. Aft 14/16...
SHRA/TSRA development expected ovr NW PR and this may result in
periods of MVFR conds at JBQ/JMZ till 14/22z. Low level winds will
be from the E to SE at around 10-15kts.


&&

.MARINE...Seas of 2 to 4 feet expected today and tonight with
winds generally 17 knots or less. There is a moderate risk of rip
currents across North Central-PR and E-St. Croix.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 89 78 90 79 / 20 10 10 10
STT 89 80 90 79 / 30 20 20 20

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
149 PM AST SUN AUG 14 2016

.SYNOPSIS...Surface high pressure across the western Atlantic
will continue to produce moderate trade winds across the region
next several days.

&&

.DISCUSSION...scattered showers with strong thunderstorms
developed across the western interior and northwest sections of
Puerto Rico. Very heavy rainfall with strong gusty winds and
excessive lightning was observed with this activity. This activity
was due to the combination of strong daytime heating...available
moisture and local effects. All of this activity is expected to
dissipated near sunset.

A relatively drier air mass is expected to move across the area
this evening through Wednesday, which means that mainly locally
induced showers and thunderstorms are expected. A Saharan air
layer is expected to encompass the region from the east on Monday
and Tuesday. This feature will limit even more the shower and
thunderstorm activity over the local islands for the next several
days. However, it is still possible to have some showers over
eastern Puerto Rico overnights and showers and thunderstorms in
the afternoons across western PR.

&&

.AVIATION...SHRA/TSRA will continue over northwest Puerto Rico and
this may result in periods of MVFR or even IFR conditions at
TJBQ/TJMZ until 14/22z. After 14/22Z mostly VFR conditions expected
to prevail across the local flying area with vicinity -SHRA in and
around TIST and TISX. Low level winds will continue from the E to SE
at around 10-15kts until 14/23Z, diminishing to around 10 knots
after that.


&&

.MARINE...Seas up to 5 feet and winds up to 15 knots are expected.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 78 90 79 90 / 10 10 10 20
STT 80 90 79 90 / 20 20 20 20