Caribbean - Central America Weather

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
359 AM AST THU SEP 15 2016

.SYNOPSIS...A mid to upper level ridge will remain as the main
weather feature across the northeast Caribbean through Friday.
The upper ridge is then expected to erode rapidly as an upper
level trough return to the region during the upcoming weekend.
Surface high pressure across the western Atlantic and tropical
storm Ian well northeast of the local islands will maintain a
gentle to moderate easterly wind flow for the next few days.

&&

.DISCUSSION...Doppler radar indicated brief isolated passing
showers embedded in the easterly wind flow moving across the USVI
as well as across eastern coastal municipalities of Puerto Rico
overnight and early this morning. The rainfall accumulations
associated with this activity were generally minimal.

An upper level ridge will hold as the main weather feature across
the region until at least Friday. Although this feature will limit
the moisture content of the local airmass today, the available
moisture is expected to combine with daytime heating and local
effects this afternoon to produce a new round of showers and
thunderstorms mostly across western and interior sections of
Puerto.

An upper level trough is expected to amplify across the area
Saturday and Sunday. Expect only the typical afternoon shower
activity over western and interior sections of Puerto Rico during
the upcoming weekend. However, by early next week, the upper
trough is expected to positioning west of the region...producing
more moisture transport across the local islands for the
development of showers and thunderstorms.

&&

.AVIATION...VFR conds expected across most of the forecast area.
However...brief MVFR conds likely in and around TJMZ due to SHRA
development in W interior of Ctrl Mtn range FM 15/18Z-15/22Z. VCTS
also possible near TJPS and TJBQ. NE to E winds at 10-15 kt BLO
FL150. Except for sea breeze variations,SFC wnd mainly fm E 10-15
kts.

&&

.MARINE...Seas will remain up to 5 feet today. Winds will continue
from the East to ENE at 10-15 knots through the end of the
workweek.

&&

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

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[cycloneye]

[Div][
Area Forecast Discussion
National Weather Service San Juan PR
157 PM AST THU SEP 15 2016

.SYNOPSIS...Mid to upper level ridge will dominate the local region
over the next few days. This will lead to a generally fair weather
pattern across the Puerto Rico and the U.S. Virgin Islands. Upper
level trough will retrogress over the Eastern Caribbean during the
weekend. As a result...the atmosphere will destabilize somewhat
across the local area allowing moisture to pool across Puerto Rico
and the U.S. Virgin Islands especially late in the weekend and
early next week. The next surge of deep moisture will be associated
with the Tropical Depression 12 late next week.

&&

.DISCUSSION...A relatively dry and stable air mass is prevailing
across the local islands today. Satellite Precipitable Water Analysis
as well as 12Z TJSJ indicated values near 1.5 inches, about 20% below
normal. In addition, lapse rate below 5 C/km suggest a relatively
stable air mass. However...strong daytime heating induced the
development of sea breezes resulting scattered afternoon convection.
Upper level ridge may limit the vertical development of the showers...
however a few thunderstorms can not ruled out later this afternoon.

Upper level trough/TUTT is forecast to move over the region during
the weekend. However...the best dynamic aloft will likely occur
between Sunday and Monday as the TUTT relocates over the Mona
Passage. This trough aloft will allow deeper moisture to pool
over the area...favoring the development of showers and
thunderstorms across the regional waters and portions of the
islands late in the weekend and early next week. The latest
forecast from the National Hurricane Center suggest that Tropical
Depression 12 will approach the Leeward Islands by Midweek next
week. At this time...the impacts associated with this tropical
cyclone on Puerto Rico and the U.S. Virgin Islands are still
unknown. However...most of the operational models suggest a surge
of moisture late Wednesday into Thursday. This will likely enhance
the potential of showers and thunderstorms across the local region
late next week.

&&

.AVIATION...MVFR conds and mountain obscurations will remain
possible in JMZ as well as in the vicinity of JPS/JSJ in SHRA/TSRA
through at least 15/22z. Elsewhere, VFR conds expected to prevail.
Easterly winds 10-15 knots becoming light and variable overnight.

&&

.MARINE...All the local and regional buoys have reported seas of 4
feet or less and winds around 10-15 knots. This marine conditions
will likely remain through at least midweek next week. Therefore...
no Small Craft Advisories are anticipated over the 5 days.

&&

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

[cycloneye]

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
456 AM AST FRI SEP 16 2016

.SYNOPSIS...Slight drying will occur today and Saturday before the
reflection of an upper level low brings an increase in showers and
thunderstorms Sunday through Tuesday. Tropical Storm Karl is not
expected to reach this longitude until Thursday at the earliest.

At upper levels...A weak upper low northeast of the
Leeward Islands will move across the local area on Sunday. High
pressure is expected to build across the Atlantic waters north of
the area Thursday through the following Sunday.

At mid levels...An inverted trough north of the mouth of the
Amazon River will move slowly westward and into the local area on
Sunday. A second low, associated with Tropical Storm Karl is
expected to move west through the tropical Atlantic, turning
northwest as it approaches the windward islands.

At lower levels...A trough east of the local area is a reflection
of the upper level low. It will cross the local area just behind
that low on Sunday bringing an increase in showers and
thunderstorms. Tropical Storm Karl will reach the western end of
the tropical Atlantic on Wednesday night brining low level winds
sharply around to the northeast.


&&

.DISCUSSION...A few showers continued to stream around the U.S.
Virgin Islands and onto the eastern tip of Puerto Rico. Otherwise,
skies were mostly clear. Precipitable water is expected to reach a
minimum this evening. Although local effects will generate some
showers and thunderstorms, especially in the western interior of
Puerto Rico, activity is expected to be less than yesterday. And,
although moisture recovers somewhat Saturday, showers and
thunderstorms will again have less coverage than yesterday. The
upper level low is generating a trough at lower levels that will
bring better moisture and convective activity Sunday. This
moisture will linger through Tuesday. Tropical storm Karl will
remain surrounded by Saharan dust, models show it moving north of
20 north between Monday and Tuesday night. At this time it is not
expected to have much direct impact on Puerto Rico or the U.S.
Virgin Islands, but should pass northeast of the area, but it is
too early to say with a great deal certainty.

&&

.AVIATION...Mainly VFR conditions expected through the morning
hours across all the terminals. SHRA/TSRA developing between 16/17-
22z across the interior/SW quadrant of PR could impact mainly the
flying area of TJMZ/TJPS. BKN to OVC ceiling at FL020-FL040 and
mountain obscurations are expected with this activity. Sfc winds
will continue from the east to east northeast at 5-15 knots and
gusty near SHRA/TSRA and with sea breeze variations aft 16/13z.


&&

.MARINE...Seas will slowly increase through Monday in the
Caribbean and through Wednesday in the Atlantic. Nevertheless the
need for small craft advisories is not anticipated through
Wednesday of next week. Showers and thunderstorms will increase
beginning on Sunday and

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 90 79 90 78 / 30 0 10 20
STT 89 82 90 79 / 30 10 20 30

&&

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
221 PM AST FRI SEP 16 2016

.SYNOPSIS...Low to mid level induced trough will continue to move
Across the region today through Saturday. This will maintain
fairly Light east to northeast trade winds. Winds are expected to
become More east southeast sunday through monday as high pressure
ridge will build across the Northeastern Caribbean and local region.
Mid To upper ridge aloft will maintain a north to northeast wind
flow Across the region. This will support an overall subsidence
cap with stable conditions aloft through early Sunday. By late
Sunday through early next week, an upper trough will move westward
across the forecast area and gradually erode the upper level ridge.

&&

.DISCUSSION...Local sea breeze convergence and diurnal effects
lead to showers and isolated thunderstorms mainly over the interior...
west and southwest Puerto Rico, as well as on the downwind side
and just off the coast of the U.S Virgin Islands. The showers over
Puerto Rico lead to minor ponding of water on roadways and in poorly
drained area. Expect activity over land to diminish just around sunset
leading to partly cloudy to mostly clear skies during the overnight
hours. By early morning a few passing showers may affect the coastal
waters and parts of the east coastal sections of the islands, but
no significant rainfall is expected.

On Saturday similar weather conditions with locally and diurnally
showers expected in some areas, but for the most part mostly sunny
and fair weather skies expected through early Sunday. By Sunday
afternoon through Monday, a surge of low level moisture will move
across the region to slightly increase the chance for afternoon
showers and isolated thunderstorms over parts of the islands...
especially along the northern half of Puerto Rico.

A drier pattern so far expected for Tuesday and Wednesday of next week
in advance of the Tropical Storm Karl which is so far forecast to move
well northeast of the region by Wednesday thereby inducing a northeast
wind flow.

&&

.AVIATION...Mainly VFR conds expected across most of the forecast
area. MVFR conds and mountain obscuration are likely in and around
TJMZ and TJPS between 17Z-22Z. NE to E winds at 10 kt are expected
to prevail fm SFC to FL200.

&&

.MARINE...All the local and regional buoys continued to report
seas of 4 feet or less and winds around 10 to 15 knots. Based on
recent trends and model guidance, marine conditions will likely
remain the same through at least early next week. Therefore...no
Small Craft Advisories are anticipated through at least Tuesday of
next week.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 79 90 78 88 / 0 10 20 30
STT 82 90 79 89 / 10 20 30 30

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
516 AM AST SAT SEP 17 2016

.SYNOPSIS...An induced trough will move across the area pulling
the showers and thunderstorms, now over the Lesser Antilles,
across the forecast area. Scattered showers and a few
thunderstorms will then continue for most of next week and early
into the following week.

At upper levels...a TUTT is over the northern Leeward Islands and
will continue across Puerto Rico and the U.S. Virgin Islands
tonight and Sunday. The center will pass south of Puerto Rico and
enter the Dominican Republic by Tuesday night. This will be
followed by a mild ridge by the end of the week. A 40 knot jet
will be found over the northeastern corner of the forecast area by
next weekend.

At mid levels...A weak trough over and just east of the Lesser
Antilles will move across the area Sunday. A second low,
representing Tropical Storm Karl, in the tropical Atlantic will
move to north of Puerto Rico on Thursday. When it finally leaves
high pressure will build across the Atlantic north of the area
early the following week.

At lower levels...The TUTT low moving across Puerto Rico and the
U.S. Virgin Islands has induced a trough at the surface which will
pull across the local area on Sunday. Currently it is producing
showers and thunderstorms over the Windward Islands and should do
the same for the U.S. Virgin Islands and Puerto Rico. Although
Karl is still expected to have little effect on the local area,
patches of modest moisture will keep showers and isolated
thunderstorms in the forecast for the foreseeable future.

&&

.DISCUSSION...Scattered showers were seen over the Atlantic and
Caribbean waters in the northwest and southeast part of the
forecast area and a few of these did move over eastern PuertoRico
in the east northeast flow. Although a few showers passed around
the U.S. Virgin Islands no rain was observed over land there.
Currently moisture is at a minimum ahead of a trough whose axis is
currently northeast/southwest over Guadeloupe. The best convection
is generally behind this axis. Thunderstorms were observed
northeast of the Leeward Islands and the IR loop indicates
persistent convection in the vicinity. The TUTT will move across
Puerto Rico on Sunday with the same moisture and similar
conditions are expected here on Sunday as were had there
overnight. Showers should move into the USVI on Sunday morning and
be well developed over most of Puerto Rico by mid-afternoon on
Sunday. Urban and small stream flooding over much of the islands
cannot be ruled out. Showers and moisture will continue through
Tuesday afternoon, with the attendant showers and isolated
thunderstorms in the familiar daily pattern. Since Karl will pass
more than 300 nm north of the area Thursday morning according to
most models and the National Hurricane Center, if indeed it does
not decay into an open wave or tropical depression first as the
GFS suggests, moisture will be very modest owing to the distance
north of the forecast area it is expected to pass and the fact
that the best moisture is now and will continue to be considerably
northeast of the center. Moisture in the southeast flow to follow
will be modest but that same southeast flow will send temperatures
on the north coast back into the lower 90s for Friday and the rest
of the weekend.

&&

.AVIATION...In general, VFR conditions expected across the
USVI/PR terminals. An induced trough will cause wx condtions to
deteriorate at TNCM/TKPK this morning, SHRA/TSRA will result in
MVFR conds. During the afternoon, mtn obscurations/SHRA/TSRA are
possible across the interior and west sections of PR. This
activity may impact mainly TJPS/TJMZ and the VCTY of TJBQ btwn
17/17-22z. Sfc winds will continue from the east to east northeast
at 5-15 knots with sea breeze variations after 17/13z and gusty
near SHRA/TSRA.

&&

.MARINE...Seas are forecast to increase slowly during the week
during the relatively distant passage of Tropical Storm Karl to
the northeast. They should peak around 7 feet at the outer buoy
and remain below 7 feet in the local Atlantic and Caribbean
waters. At this time small craft advisories are not expected
during the next 10 days.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 90 78 89 76 / 10 20 50 60
STT 90 79 87 76 / 30 40 40 70

&&

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
201 PM AST SAT SEP 17 2016

.SYNOPSIS...Upper low, currently over the leeward islands is
expected to to move west and across the Caribbean waters tonight,
Sunday and Monday, with its center just south of the Dominican
Republic on Monday night. This upper low has an induced surface
trough that will move into the local area by late tonight into
Sunday causing an increase in the shower and thunderstorm activity
over the local islands on Sunday.

&&

.DISCUSSION...Moderate to locally heavy showers have already
developed across central and western PR this afternoon due to the
combination of the local effects and diurnal heating with the
available moisture, which is higher than what the models had
predicted. There is also some showers streaming off the USVI as
well as Culebra and Vieques. The afternoon convection is expected
to develop some thunderstorms later in the afternoon, persisting
until around sunset. Some urban and small stream flooding will not
be ruled out for portions of central and western PR this
afternoon.

The approaching surface trough is expected to bring an increase in
moisture as well as shower and thunderstorm activity. The latest
model guidance suggests that by late tonight, the USVI and nearby
areas could be experiencing some of the showers and thunderstorms
as the trough moves west, eventually reaching eastern PR very
late tonight into early Sunday.

Clouds, rain and thunder are expected through the day on Sunday
across the local islands due to the upper low and the induced
surface trough moving through. Urban and small stream flooding is
to be expected on Sunday across several areas in Puerto Rico, with
maybe the exception of South Central and Southwestern PR since
that seems to be the area with the least amount of rain expected,
having said that, we cannot rule out that some of those sections
may experience significant showers as well since this surface
trough already has a large area of showers and thunderstorms
associated with it and it is possible that most of PR and the USVI
will experience significant showers. The local effects should play
a role and give the northern half and the eastern sections of PR
more rainfall than the South of PR and the USVI under the
southeast wind flow.

For the upcoming workweek, the upper low is still over the local
area on Monday which will help in the development of showers and
thunderstorms across PR in the afternoon hours. Thereafter, the
southeasterly flow is expected to prevail which will cause the
afternoon convection to occur across the central, western and
northwestern sections of PR every day this upcoming week. The USVI
can expect isolated to scattered brief showers and the San Juan
metro area can also expect afternoon showers with isolated
thunderstorms but at this time central and western PR look like
they will be getting the more significant or usual afternoon
showers and thunderstorms.


&&

.AVIATION...MVFR conds and mountain obscuration are likely in and
around TJMZ as well as the Leeward Islands terminals thru 22Z. VCTS
possible near TJPS and TJBQ with the afternoon convection. Easterly
winds at 10-15 kt are expected to prevail fm SFC to FL200.
However...increasing SHRA/TSRA activity is forecast across the
flying area after 18/00Z under the influence of an upper level
low.

&&

.MARINE...Seas of 4 feet or less and winds around 10-15 knots are
expected across the regional waters. No significant changes are
forecast through midweek next week. Therefore... no Small Craft
Advisories are anticipated over the 5 days.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 78 89 76 88 / 20 50 60 60
STT 79 87 76 89 / 40 40 70 60

&&

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
535 AM AST SUN SEP 18 2016

.SYNOPSIS...A trough crossing through Puerto Rico today will bring
an increase in showers and thunderstorms today and tonight for
much of the area. Tropical Storm Karl is expected to pass north of
the area Thursday with minimal effects and only a slight increase
in moisture. Drier weather is anticipated next weekend, but
scattered showers and a few thunderstorms will still occur in the
west during the afternoons with a few light showers in the
mornings around the U.S. Virgin Islands and the east coast of
Puerto Rico.

At upper levels...A trough with a low centered 200 miles south of
Vieques will cross through Puerto Rico this afternoon and move
out of the area late tonight. High pressure will cross north of
the area late Friday night.

At mid levels...High pressure dominates the central Atlantic. A
trough over Puerto Rico will continue westward. A low pressure
associated with Tropical Storm Karl will pass north of the local
area Wednesday night. High pressure across the Atlantic will then
sag slowly south over the area over the weekend. Mid levels remain
relative dry over the area after Tuesday.

At lower levels...A trough has passed Saint Croix and will move
through Puerto Rico during the day today. Moisture will then taper
off through Wednesday night. Tropical Storm Karl is about 1500
miles due east of San Juan, Puerto Rico and will pass north of the
area early Thursday morning with minimal effect, although there
will be some additional moisture Thursday and Friday. A ridge will
extend broadly over the area Saturday.

&&

.DISCUSSION...Showers and thunderstorms moved into the eastern
half of the forecast area and increased in number and intensity
until a little after 3 AM AST. Thereafter showers diminished
considerably and lightning strikes became sparse. Activity is
expected to increase again as the low level trough approaches the
Puerto Rican mainland and solar heating commences. Urban and small
stream flooding is possible in Puerto Rico and the U.S. Virgin
Islands, today and early tonight. Moisture diminishes slowly after
today, but showers and thunderstorms will continue, though,
somewhat abated. Tropical Storm Karl is expected to pass well
north of the local area with only a slight increase in moisture.
Low level winds will also weaken and turn much more northerly.
With light winds and somewhat increased moisture urban and small
stream flooding would be expected in some localized areas--mainly
in the interior Thursday and possibly Friday. Drier conditions
return for the weekend, but scattered showers and thunderstorms
will continue right into the beginning of Fall and temperatures in
the lower elevations of the USVI and on the north coast of Puerto
Rico will remain around 90 degrees.

&&

.AVIATION...A surface trough will continue to produce SHRA from time
to time across the local area. Most of the activity should diminish
during the morning hours, but SHRA/TSRA are expected to develop once
again during the late morning and into the afternoon hours. Periods
of MVFR conditions are expected mainly across TJBQ/TJMZ/TJPS btwn
18/16z-23z, but are possible across TJSJ too. Sfc winds from the E-
ESE at 10-15 kts with sea breeze variations after 18/13z and gusty
near SHRA/TSRA.

&&

.MARINE...Seas will increase through Thursday, but should remain
below 6 feet especially if winds fail to develop in Karl`s western
quadrant. Small craft advisories are not expected during the next
10 days.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 76 90 79 90 / 60 60 50 50
STT 77 89 79 89 / 70 60 50 50

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
146 PM AST SUN SEP 18 2016

.SYNOPSIS...Upper level low/TUTT just south of the local region
is supporting an induced surface trough that is moving across
Puerto Rico and the U.S. Virgin Islands. Both features will
enhance the potential of showers and thunderstorms across the
islands through Monday. Then...moisture and instability will
gradually diminish the rest of the week. However...bands of
moisture embedded in the trade winds will bring scattered showers
at times.

&&

.DISCUSSION...Water Vapor Satellite imagery shows a cyclonic
circulation over the Eastern Caribbean south of Puerto Rico and
the U.S. Virgin Islands. This circulation is associated with a
upper level low/TUTT. The TUTT will keep the atmosphere relatively
unstable through at least Monday. Therefore...expect showers and
thunderstorms affecting the surrounding waters and portions of the
islands from time to time. The heaviest rainfall is still expected
over the Cordillera Central...North and West Puerto Rico during
the afternoon hours.

From Tuesday to Friday...upper level low will move over the Western
Caribbean by midweek. At the same time...a mid level ridge will
build over the Eastern Caribbean leading to generally stable
conditions. The overall moisture will diminish and the winds will
subside the rest of the work week...in response to Tropical Storm
Karl passing well north of the local area. As a result...Diurnal
effects will play a major role in the generation of showers over
the islands as a light steering winds prevail. Therefore...afternoon
showers and thunderstorms are likely each afternoon over the windward
side of the islands due to the sea breeze convergence.

&&

.AVIATION...A trough across the region will continue to produce
periods SHRA across the local area tonight. Periods of MVFR
conditions will continue mainly across TJBQ and TJMZ until 18/22Z
diminishing after that. VCSH and brief periods of MVFR are
expected this evening across the Leewards and USVI taf sites.
Surface winds from the E-ESE at 10-15 knots are expected to
diminish tonight to around 10 knots.

&&

.MARINE...Seas up to 4 feet and winds up to 15 knots are expected
across the coastal waters. Small craft advisories are not expected
during the next several days. Marine conditions are subject to
chance...depending of the intensity of Tropical Storm Karl as
moves over the Atlantic Waters.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 76 90 79 90 / 30 60 50 50
STT 77 89 79 89 / 50 50 50 50

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
601 AM AST MON SEP 19 2016

.SYNOPSIS...
The interaction between an Upper level low/TUTT, to the South
West, and an Upper level high pressure, to the North of the local
islands, will produce enough instability. These two features will
combine with a Tropical Wave, which is moving across the region
today, to enhance the potential of showers and thunderstorms
across the islands. Then, moisture and instability will gradually
diminish during the rest of the week. However...surges of
moisture embedded in the trades will bring scattered showers each
day.

&&

.DISCUSSION...
Scattered showers with isolated thunderstorm were detected with the
Doppler Radar and Satellites imagery overnight. A thunderstorm
moved inland from Southeast to Northeast Puerto Rico. Also, other
thunderstorms were observed moving westward across the Atlantic
and Caribbean waters. Most of the thunderstorms moved away from
the County Warning Area or dissipated early this morning.

For the rest of this morning, showers are expected to continue
across the regional waters, some of these showers will move
over the windward sections of Puerto Rico and the U.S. Virgin
Islands. This activity is associated with a Tropical Wave, which
is moving across the islands today. As a result the potential for
isolated thunderstorms is present during the morning hours too.

The tropical wave is expected to interact with an upper level
trough to produce another round of showers and thunderstorms along
and to the North and West of the Cordillera Central this
afternoon. Some of these thunderstorms will be capable of produce
frequent lightning, minor flooding, gusty winds and hazardous
driving conditions. In addition, maximum temperatures will range
from the lower 90s on the south and west coasts to around the mid
70s in the highest mountain areas.

From Tuesday to Friday...A mid level ridge will build over the
Eastern Caribbean leading to generally stable conditions. But
surges of moisture embedded in the trade winds will bring periods
of showers across the region from time to time. Also, thunderstorm
development is possible each afternoon mainly across the interior
sections of PR. Tropical Storm Karl is expected to pass well
northeast of the local area.

&&

.AVIATION...
Mainly VFR conditions expected through the forecast
period across all terminals with possible VCSH across
TIST/TISX/TJSJ/TNCM/TKPK through 19/16Z. SHRA and possible TSRA
developing between 19/17-22z across the interior and western PR
impacting mainly TJMZ/TJBQ and vcnty of TJPS. Low level winds will
be light east southeasterly overnight, increasing to around 10-15KT
after 19/13Z with sea breeze variations developing. Winds FL170-450
diminishing to less than 25 kt and becoming southeast by 19/18z.

&&

.MARINE...
Mariners can expect tranquil marine weather conditions with seas
up to 4 feet and winds at less than 18 knots. However, showers
and thunderstorms are possible across the regional waters, as a
tropical wave moves across the region today. Winds are expected to
continue from the East to Southeast until tuesday, then are
turning from the Northeast to North as Tropical Storm Karl pass
off to the Northeast of the region. For the beach goers, there is
a slight risk of rip currents across most of the local waters.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 91 79 90 79 / 50 50 50 30
STT 88 79 89 78 / 50 40 40 30

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
231 PM AST MON SEP 19 2016

.SYNOPSIS...Upper level low/TUTT southwest of Puerto Rico is
enhancing the potential of showers and thunderstorms across the
Central and Eastern Caribbean. The proximity of the upper trough
will keep the atmosphere somewhat unstable until Tuesday. Then...
moisture and instability will gradually diminish the rest of the
week as a mid to upper level ridge builds near the region on
Wednesday. However...bands of moisture embedded in the trade
winds will bring scattered showers at times.

&&

.DISCUSSION...Satellite imagery shows a cyclonic circulation over
the Central Caribbean. This circulation is associated with a upper
level low/TUTT that is favoring the development of showers and
thunderstorms over Hispanola and Puerto Rico. The rest of the
afternoon...expect additional showers and thunderstorms developing
over most of Puerto Rico except the southern coastal plains. The
most intense rainfall will focus across the Cordillera Central
and Northwest Puerto Rico later this afternoon. Although...some
showers will linger over land during the evening hours...the bulk
of the afternoon convection should dissipate near sunset.

From midweek through the weekend...upper level low will move away
from the region into the Western Caribbean by midweek. Giving way
to a mid level ridge that will build over the Eastern Caribbean.
This ridge aloft will result in generally stable conditions. The
overall moisture will diminish and the winds will subside the rest
of the work week...in response to Tropical Storm Karl passing well
north of the local area. As a result...Diurnal effects will play a
major role in the generation of showers over the islands. Therefore...
afternoon showers and thunderstorms are likely each afternoon over
the windward side of the islands due to the sea breeze convergence.

&&

.AVIATION...SHRA/TSRA developing between 19/18-22z across the
interior and western PR impacting mainly TJMZ/TJBQ and vcnty of TJPS
and TJSJ. Low level winds will be from the ESE at 10-15KT with sea
breeze variations through 19/23Z, thereafter SFC winds will be light
ESE during the overnight hours. VCSH across the local terminals
except TJMZ and TJBQ through the overnight hours.

&&

.MARINE...Seas up to 4 feet and winds up to 15 knots are expected
across the coastal waters. Small craft advisories are not expected
during the next several days. Marine conditions are subject to
chance...depending of the intensity of Tropical Storm Karl as
moves over the Atlantic Waters.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 79 90 79 90 / 50 50 30 30
STT 79 89 78 90 / 40 40 30 30

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
540 AM AST TUE SEP 20 2016

.SYNOPSIS...
A trofiness pattern aloft is enhancing the potential of showers
and thunderstorms across the Central and Eastern Caribbean. This
pattern will keep the atmosphere unstable for the rest of the
work week. The available moisture and instability will gradually
diminish by the end of the work week as a mid to upper level ridge
builds near the region. However, patches of low level moisture
will result in trade wind showers during the night and morning
hours, followed by afternoon showers and thunderstorms across the
islands each day.

&&

.DISCUSSION...
The Doppler Radar detected trade wind showers across the local
waters, some of them affected the windward sections of Puerto Rico
and the U.S. Virgin Islands from time to time. The preliminary
rainfall totals identified isolated rainfall amounts around a
quarter of an inch near El Yunque Rainforest and portions of East
PR.

Showers across portions of the half East section of PR and
across the U.S. Virgin Islands will continue during the morning
hours. During the afternoon, the proximity of the upper level low,
the available moisture and local effect will result in another
round of showers and thunderstorms across and to the west of the
Cordillera Central. Also showers are expected to develop and move
downwind from the U.S. Virgin Islands and the islands of Vieques
and Culebra. Some of these showers or thunderstorms could affect
the east municipalities of mainland PR, and the San Juan Metro
Area. Although the available moisture is expected to diminish
somewhat, locally induced afternoon showers and thunderstorms are
expected to continue each day at least until the end of the
workweek due to the trofiness pattern aloft.

For the rest of the workweek, the local wind flow pattern will be
dominated by the influence of Tropical Storm Karl, which is
expected to move well off to the Northeast of the local islands.
Consequently, as the winds shift from the north to northeast on
Wednesday, afternoon activity will focus to the south of the
Cordillera. Then by Thursday, a Southerly wind field is expected
to focus the afternoon activity to the North of the Cordillera
Central and downwind off to the North of the U.S. Virgin Islands.
As these changes in the wind field occurs, the winds are also
expected to become light, resulting in slow movers and long
lasting showers and thunderstorms.

&&

.AVIATION...
Moisture wrapping around an upper level low from the south will
move west and out of the the Leeward islands arnd 20/18z and out
of USVI arnd 20/22z and PR aft 21/02z. This moisture will bring
isold MVFR cigs in SHRA to TNCM/TKPK and psbly TISX. Aft 20/17Z
areas of SHRA/TSRA will bring mtn obscurations and MVFR conds to
mainly wrn PR. Winds east less than 5 kt bcmg 5 to 15 kt with sea
breeze influence aft 20/14z. Max winds alf E 30 kt arnd FL410 but
diminishing to 15 kt by 21/00z.

&&

.MARINE...
Across the regional waters, mariners can continue to expect
relatively tranquil marine conditions with seas below 5 feet and
east winds between 5 and 15 knots. The beach goers should exercise
caution mainly across the Atlantic Beaches due to a moderate risk
of rip currents.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 89 78 89 78 / 30 40 40 20
STT 88 78 89 77 / 40 40 40 40

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
209 PM AST TUE SEP 20 2016

.SYNOPSIS...Upper low northeast of the islands will merge with a
broad upper trof across the central Caribbean basin through the
end of the work week. A mid to upper ridge is forecast to build
through the weekend. TC Karl will continue to move to the
northeast/north of the region for the next several days. A weak
surface trough is expected to move across the islands on Thursday.


&&

.DISCUSSION...Numerous showers and scattered thunderstorms were
observed across the interior and western sections of PR. Also,
isolated thunderstorms developed from streamers over the U.S.
Virgin Islands and from El Yunque area into the San Juan
metropolitan area. Urban flooding was reported with the heaviest
showers specially over Utuado. Shower and thunderstorm activity
should diminish by sunset. This activity will continue to pose a
threat of urban and small stream flooding across the
interior/western sections of PR.

Upper trof pattern will continue through the end of the week.
Providing some favorable upper level dynamics that can enhance
afternoon convection over the islands. In addition, an induced
surface trof will move from the east late Wednesday night into
Thursday increasing the chances of showers and thunderstorms
activity. As the trof moves across the islands, winds will shift
from the north/northeast on Wednesday favoring convection along
the Cordillera Central into southern PR. Then winds shift once
again from the south/southeast by Thursday into early in the
weekend, favoring convection north of the Cordillera. Higher than
normal heat index is expected across coastal areas by the end of
the week due to southerly wind flow.


&&

.AVIATION...SHRA/TSRA across W-PR will affect the vicinity of
TJMZ/TJBQ with some -SHRA/SHRA across the vicinity of TJPS/TJSJ and
TIST/TISX through the afternoon hours. Tempo MVFR possible at TJMZ
this afternoon and possible until 20/10Z at TISX as there is a SHRA
currently over the terminal. After 20/23Z the activity is expected
to be greatly diminished, leaving ISOLD/SCT SHRA over the waters.
Winds will gradually turn northerly and below 10KT as the night
progresses into Wednesday.


&&

.MARINE...Seas expected to continue 3-5 feet through Wednesday.
Increasing 4-6 feet on Thursday across the Anegada Passage and
Atlantic waters where small crafts should exercise caution.
Gentle to moderate winds will continue across the waters. As
mentioned above, winds will be more from the northeast tomorrow
then southerly on Thursday. Moderate risk of rip currents will
continue through the work week mainly across the northern beaches
of PR and St. Croix.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 78 89 78 90 / 40 40 20 40
STT 78 89 77 88 / 40 40 40 40

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
535 AM AST WED SEP 21 2016

.SYNOPSIS...Upper low northeast of the islands will merge with a
broad upper trof across the central Caribbean basin through the
end of the work week. A mid to upper ridge is forecast to build
through the weekend. TC Karl will continue to move to the
northeast/north of the region for the next several days. A weak
surface trough is expected to move across the islands on Thursday.

&&

.DISCUSSION...Very light showers were observed across the local
waters...with some affecting the eastern half of Puerto Rico and
the U.S. Virgin Islands overnight. For today...strong daytime
heating...combined with available moisture are expected to
produce another round of scattered to numerous showers with
thunderstorms over the Cordillera Central of Puerto Rico. Low
level winds are expected to be more northeasterly today. Therefore
the showers and thunderstorms are expected to drift toward the
southern plains.

For the rest of the work week...as tropical cyclone Karl passes
well northeast of the area...local region will remain in a col
area...which will result in very light and variable winds across
the region. Therefore...showers and thunderstorms will move very
slowly...which will increase the chances for urban and small
stream flooding across the area especially each afternoon. This
weather pattern will continue through at least Saturday...when a
upper level ridge is expected to build across the region.

&&

.AVIATION...VCSH expected early in the morning across the Leeward,
USVI and TJSJ taf sites. From 15Z-22Z, SHRA/TSRA expected to develop
along Cordillera Central, S, W and SW PR. Tempo MVFR cond possible
at TJBQ, TJPS and TJMZ with MTN obscurations. After 20/22Z ISOLD/SCT
SHRA mostly over waters. Winds generally from the N to NE at 5 to 10
kts with sea breeze variations.

&&

.MARINE...Seas up to 6 feet and winds up to 10 knots are expected
over the coastal waters. Small Craft should exercise caution
across the offshore Atlantic waters and the Anegada passage.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 88 78 92 79 / 40 20 50 20
STT 90 80 88 80 / 40 40 40 40

[tolakram]

Looks like Luis is still offline due to the PR power outage.

http://abcnews.go.com/International/wir ... o-42268174

Hope everything is ok. I'm trying to keep up with everything you usually do.

Most Puerto Ricans faced another night of darkness Thursday as crews slowly restored electricity a day after a fire at a power plant caused the aging utility grid to fail and blacked out the entire island of 3.5 million people.

Nearly 370,000 of the 1.5 million homes and businesses served by the power utility had power back by late Thursday. Gov. Alejandro Garcia Padilla said he hoped more than half would be reconnected by Friday morning, adding that public school classes were canceled on Friday.

[cycloneye]

Looks like Luis is still offline due to the PR power outage.

http://abcnews.go.com/International/wir ... o-42268174

Hope everything is ok. I'm trying to keep up with everything you usually do.

Most Puerto Ricans faced another night of darkness Thursday as crews slowly restored electricity a day after a fire at a power plant caused the aging utility grid to fail and blacked out the entire island of 3.5 million people.

Nearly 370,000 of the 1.5 million homes and businesses served by the power utility had power back by late Thursday. Gov. Alejandro Garcia Padilla said he hoped more than half would be reconnected by Friday morning, adding that public school classes were canceled on Friday.

Thank you Mark for that.Hopefully no more outages occur.

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
200 PM AST FRI SEP 23 2016

.SYNOPSIS...Upper level ridge will continue northeast of the
region during the weekend but a weak upper level low may pass over
the local islands. Surface trough will move across the region
Monday. Active tropical wave expected to approach the local area
mid next week. Combination of local effects and available
moisture is expected to be the main contributor to active weather
for the next several days.


&&

.DISCUSSION...As expected, the light southerly winds combined with
the local effects and developed cloudiness and a few showers
across the northern half of Puerto Rico during the early afternoon
hours. The southerly winds and sunshine observed in the morning
and early afternoon caused the temperatures to rise at the San
Juan airport to 94 degrees which ties the record high temperature
for the day. Heat index values as of now were 103 for San Juan and
Saint Croix, while Saint Thomas observed a heat index of 105.

Because tropical depression Karl is to our North, the local winds
are southerly and are expected to remain as such for the rest of
the day. However...the winds will be more southeasterly by
Saturday. This southerly wind flow may cause some rather warm
temperatures across the northern municipalities of PR in areas
where cloudiness does not develop, which means that temps are
expected to be in the low 90s once again on Saturday across the
San Juan metro and other areas in the northern sections of PR.
Temps for the USVI are expected to be in the upper 80s to close to
90 for the next several days. Long range models suggest a tropical
wave moving into the Caribbean waters by late next week. The
development of this tropical wave coming out of Africa at the
moment will be very limited if any until the wave approaches the
Lesser Antilles.

&&

.AVIATION...Mostly VFR expected across the flying area except for
aftn convective development til 23/22Z along interior and NRN half
or PR and ovr coastal waters btw E PR and the NRN Leewards. After
23/22Z few passing SHRA over the coastal waters and en route btw
islands. Lgt sfc wnds fm S to SE at 5 to 10 kts blo FL200. Except
for local sea breeze variations, wnd mainly fm se at 10 kts til
23/23z...bcmg lgt/vrb to calm aft.


&&

.MARINE...Southerly winds between 5-10 knots expected overnight.
with seas up to 5 feet.


&&

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

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
543 AM AST SAT SEP 24 2016

.SYNOPSIS...Tropical Storm Karl located north of the region will
continue to result southeasterly winds across the waters and local
islands. Temperatures once again expected to be higher than
average across some coastal areas. A tropical wave expected near
the local area by mid next week.

.DISCUSSION...Tropical Storm Karl continues north of the region
and will continue to result in a light southeasterly wind flow
across the waters and local islands today through the rest of the
weekend. This will also result in higher than average temperatures
along several coastal areas...especially the north coastal areas
of Puerto Rico...as well as Vieques and Saint Croix USVI. Heat
Index values could surpass 102 degrees along these portions.

Upper level ridge will continue northeast of the region through
the rest of the weekend. For today, the GFS model continues to
indicate some patches of low level moisture moving across the
region. Some passing showers along the southern and eastern
portions of Puerto Rico is possible during the morning hours. In
the afternoon, this moisture with the local effects and warmer
than usual temperatures may combine to produce shower and
thunderstorm development mainly across the north and northwestern
portions of Puerto Rico.

Models continue to suggest a tropical wave approaching the local
waters from mid next week through late next week. This tropical
wave may bring an increase in moisture across the region.
The initial development of this wave however will be slow for the
moment.

.AVIATION...VFR conds expected across the flying area and all
TAF sites through at least 24/16z. Btw 24/16-22Z, SHRA/TSRA expected
to develop along interior and northwest sections of PR. MVFR conds
possible at TJBQ and TJBQ with MTN obscurations along interior PR.
Low level winds will be mainly southeast at 5 to 10 kts, except for
sea breeze variations along the coast.

.MARINE...Light southeast winds will prevail during the rest of
the weekend, with seas of less than 5 feet and winds 10 knots or
less. There is a moderate risk of rip currents for some beaches
along the north coast of Puerto Rico.

&&

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

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
201 PM AST SAT SEP 24 2016

.SYNOPSIS...Moderate to Gentle trade wind flow will continue
across the area with mainly air-mass showers and a few
thunderstorms through much of the week. The models are developing
a tropical cyclone next week that will enter the Caribbean on
Wednesday and strengthen some distance south of the forecast area.
This will likely bring a surge of shower and thunderstorm activity Thursday
through Monday.

At upper levels...Weak low pressure will develop in a saddle over
Puerto Rico and the U.S. Virgin Islands. After Monday...high
pressure will invade from the east and settle just south of Puerto
Rico on Thursday. High pressure will continue around the periphery
of the tropical cyclone should it form and over the local area.

At mid levels...High pressure will continue from the coast of
Africa to Cuba until mid week. High pressure will continue north
and northeast of the area through the end of next week. The GFS
shows a tropical cyclone passing about 325 miles south of Puerto
Rico`s south coast on Thursday.

At lower levels...As Tropical Storm Karl moves rapidly northeast
and away from the area during the weekend, low pressure in the
southwest Caribbean will maintain gradients for gentle to moderate
trade winds across the area through mid week. The GFS and the
ECMWF show a tropical cyclone passing south of the area that will
likely increase winds somewhat and bring better shower activity
Thursday through Sunday as it develops.

&&

.DISCUSSION...Although the 24/12z sounding for San Juan came in
drier than the soundings for both last night and yesterday
morning, the sounding remained relatively unstable and without a
significant capping inversion to impede showers. A few
thunderstorms have developed in central and north central Puerto
Rico as of 1745Z and more are expected. A few of these showers
could be heavy enough to cause urban and small stream flooding due
to their relaxed transit through the area later this afternoon.

Moisture changes little overnight or Sunday. A pulse of moisture
followed by a brief period of drier air on Monday will punctuate
an otherwise steady pattern of early morning showers on the
windward coasts to afternoon showers and thunderstorms.

On Wednesday both the ECMWF and the GFS show a low or tropical
cyclone entering the Caribbean across St. Lucia and the Grenadines
and transiting about 325 miles south of Puerto Rico`s south coast.
The models have oscillated across the Caribbean in earlier
iterations of the forecast trajectory, but seem to have settled
on this path for the last several runs. The NWS will monitor this
system--Disturbance #1--closely. See www.nhc.noaa.gov for more
details.

Weather to follow the transit of this system will become
increasingly moist and unstable such that showers and
thunderstorms will increase into the following weekend.

&&

.AVIATION...VFR conds expected to prevail across the flying area and
all TAF sites durg prd. However at least until 24/22Z, SHRA/TSRA
are fcst to develop along interior and west sections of PR and
vcty of the USVI. Brief MVFR in aftn convection will be possible
at TJMZ and TJBQ and Vcty TJSJ with MTN obscurations along the
Ctrl Mtn Range of PR. Low level winds will be mainly E-SE at 5 to
15 kts blo FL200, except for sea breeze variations along the
coast.


&&

.MARINE...Gentle to moderate trade winds have kept seas generally
below 5 feet and this is expected to continue until the passage of
the tropical cyclone forecast by the GFS and mentioned above. At
this time the model is forecasting up to 17 foot seas and up to
30 knot winds in our southern waters. Should the Disturbance--now
several hundred miles south southwest of Cabo Verde develop it is
at this time not expected to deliver such high seas or strong
winds as the model is forecasting for the local Caribbean waters
due to the tendency of the GFS to expand the wind and pressure
fields of tropical systems. Nevertheless small craft advisories
may be necessary beginning Thursday.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 79 90 79 91 / 20 20 0 20
STT 80 90 79 90 / 10 10 10 10