Caribbean - Central America Weather

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
305 AM AST Tue Oct 2 2018


.SYNOPSIS...Upper level ridge will linger across the region but
will erode today, as a broad trough spread over the Atlantic
deepens and become amplified across the southwest Atlantic. A
subtropical jet segment will move just north of the region to
maintain divergence aloft and unstable conditions today. In the
low levels, distant Tropical Storm Leslie and a broad developing
surface trough across the central and eastern Caribbean will
continue to disrupt the local synoptic pattern and maintain light
trade winds across the area through at least Wednesday. By the end
of the work week, a tropical wave is forecast to enter the eastern
Caribbean and increase low level moisture transport and instability.
This will interact with an elongated upper-level trough resulting
in a wet and unstable weather pattern across the forecast area.


.SHORT TERM...Today through Thursday...

The local islands lies between a broad area of low pressure across
the Central Caribbean and tropical storm Leslie northeast of the
region. This setup will maintain a weak steering flow across the
Northeast Caribbean over the next few days. In addition, a mid level
trough is forecast to develop southwest of Puerto Rico later today
into Wednesday, providing good upper level dynamics across the local
area. Both factors, the weak steering flow and the good ventilation
aloft will favor the development of intense showers and thunderstorms
across the Cordillera Central and interior portions of Puerto Rico
each afternoon. In contrast, minimal shower activity is forecast
across the U.S. Virgin Islands through midweek, however high level
clouds will maintain the skies partly cloudy.

A tropical wave located east of the Windward Islands this morning is
forecast to approach the local islands by Thursday. This will bring
additional moisture and instability across the U.S. Virgin Islands
and Puerto Rico. Therefore, a few rounds of scattered showers will
be likely on Thursday as the wave crosses the local area.

.LONG TERM...Friday through Wednesday...

Recent model guidance continued to suggest the upper levels
to become more favorable and unstable by Friday as the high
pressure ridge erodes and an elongated trough becomes amplified
and sags just north and west of the region. This along with
increasing tropical moisture accompanying a tropical wave and
local and diurnal effects will result in increased early morning
and afternoon convection across the islands and coastal waters
each day and into the early part of the upcoming weekend.

The instability aloft and the moisture associated with the tropical
wave, along with a broad surface trough forecast to develop and
lift northwards across the central and eastern caribbean, should
maintain a fairly moisture pattern across the region through at
least Saturday. Although some improvement is expected by Sunday
and into the following week, there still remain uncertainties in
the location and timing of the developing surface trough and
associated moisture field. However, a fairly moist and unstable
weather pattern will remain possible through Saturday with gradual
improvement in the weather conditions on Sunday and into early
next week, as the mid to upper level ridge is to build overhead
once again and help to erode moisture transport and pooling across
the forecast area. Another tropical wave is forecast to approach
the region by late Tuesday or Wednesday.

&&

.AVIATION...VFR conds thru at least 02/17Z. However, VCTS are
possible at the TJSJ,TJMZ,TJSJ and TJPS between 18Z-22Z as TSRA are
forecast to develop over the Cordillera Central. Brief MVFR conds
can`t ruled out this afternoon if storms drift briefly over the
terminals. Light winds are expected below FL250 thru the forecast
period.

&&

.MARINE...Seas will continue to subside today. Light east to
southeast trade winds and overall seas of 3 to 5 feet can be
expected through today. However, another pulse of northeasterly
swell action is forecast to arrive and create hazardous marine
conditions by Wednesday through at least Thursday.

&&

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

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
525 AM AST Wed Oct 3 2018

.SYNOPSIS...Winds will remain light and variable through Thursday,
leading to intense showers and thunderstorms each afternoon due to
strong sea breeze convergence over the Cordillera Central. A wetter
weather pattern is forecast during the weekend as a wet southerly
flow establish over the eastern Caribbean.

&&

.SHORT TERM...Today through Friday...

Minimum moisture occurring around 03/12Z this morning. Moisture then
increases through Sunday. A col lies between Puerto Rico and the U.S.
Virgin Islands and Tropical Storm Leslie and is causing light and
variable winds at lower levels. Leslie is not expected to move
farther north until late Thursday which will then allow winds to
become more southeasterly due to a ridge nosing in from the central
Atlantic and low pressure in the southwest Caribbean. This flow will
bring considerable moisture into the area with increasing
precipitable water values and increasing shower and thunderstorm
activity. Although the jet at upper levels (near 150 mb) lifts to
the north, the TUTT will remain in the proximity. Favorable
divergence values aloft tend to hold over or near the area through
the end of the period and beyond. There will be an increasing chance
for urban and small stream flooding in afternoon thunderstorms today
and Thursday. Thunderstorms will also increase and then linger over
and around eastern Puerto Rico and the U.S. Virgin Islands overnight
into Friday.

.LONG TERM...Saturday through Thursday...

A wet and unstable pattern will establish over the region during
the weekend. The broad area of low pressure that is located over
the Central Caribbean is forecast to elongate as it moves slowly
to the northwest. The broad cyclonic flow around the low pressure
will induce a wet southerly flow across the local area. This will
bring excessive moisture across the local islands. The influx of
deep tropical moisture will also enhance the instability across
eastern Caribbean during the weekend. As a result, cloudy skies
with periods of scattered and numerous showers are likely Saturday
and Sunday.

Operational models are suggesting less moisture and instability
early next week. This will limit somewhat the shower and thunderstorm
coverage Monday and Tuesday. Then, the next tropical wave is forecast
to approach the region by midweek, increasing again the potential
for showers and thunderstorms.

&&

.AVIATION...Mostly VFR conds should continue across all TAF sites
thru at least 03/18Z. Btwn 03/18-20Z expect SHRA/TSRA to dvlp
interior PR to give TAF sites TJMZ/TJBQ/TJPS at least VCTS till arnd
03/21Z. Some isold SHRA arnd TNCM/TKPK btwn 03/16-04/03Z. Sfc winds
lgt and vrb but sea breezes up to 12 kt dvlpg aft 03/14Z til arnd
03/21Z. Max winds WNW 50-75 kt btwn FL350-480--highest nr FL440
diminishing aft 03/12Z.

&&

.MARINE...Seas will gradually build to 6-8 feet later today as a
long period northerly swell will invade the local Atlantic Waters
and Caribbean Passage. These large swells will create hazardous
marine conditions through at least the end of the work week. High
surf and life threatening rip currents are the main impacts of
these swells. Also, minor coastal erosion are possible during
high tides.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 87 79 88 78 / 40 30 60 40
STT 87 78 88 77 / 30 40 60 60

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
521 AM AST Thu Oct 4 2018

.SYNOPSIS...Rich moisture generating mostly cloudy skies, showers
and isolated afternoon thunderstorms will continue over the area
with only a few breaks during the next 7 days. Winds will increase
somewhat over the weekend.

&&

.SHORT TERM...Today through Saturday...

Satellite imagery shows a broad area of low pressure south of
Jamaica. The subequatorial ridge over Colombia/Venezuela is
producing strong westerly winds aloft that are pushing high clouds
over the Eastern Caribbean. These cloudy conditions will likely
persist through the end of the week. At low levels, a weak tropical
wave is moving across the eastern Caribbean this morning, leading to
an increase in moisture content across the local area. Under these
wet and unstable conditions, expect an active afternoon with
intense showers and thunderstorms developing over the Cordillera
Central, then drifting slowly towards the north-northwest. The
high clouds may delay the onset of the afternoon convection, but
it will likely begin early in the afternoon, around 04/18Z.

The forecast for Friday and Saturday is somewhat difficult. With
dense mid to upper level clouds, the diurnal heating will be
affected. This will mean a lot of moisture and instability but
weak low level forcing. At this time, we are keeping the scattered
to numerous showers in the forecast for Friday and Saturday. The
decision was made because a mid-upper level trough will deepen
north of Puerto Rico and may bring some of the forcing needed for
triggering the convection.

.LONG TERM...Sunday through Thursday...
Hurricane Leslie will likely be a tropical storm by Friday, but
will still be about 1350 miles north northeast of San Juan on
Sunday. From there it does begin to move east and away from the
area. Gentle to moderate flow will continue over the area from the
east or east southeast as high pressure builds in over the
western Atlantic Monday through Thursday. The GFS shows little
change in the moisture levels other than daily fluctuations around
2 inches of precipitable water. The model also shows a little
weakness in moisture between 850-700 mb and implies a heavy canopy
of mid and upper level clouds throughout the period. This
probably will not be enough to inhibit convection in the usual
diurnal pattern so grids reflect showers and isolated afternoon
thunderstorms each day. Also divergence at upper levels from the
TUTT meandering to our north should enhance whatever activity that
can get started from surface heating caused by the filtered sun.

&&

.AVIATION...VFR conds thru at least 04/17Z. However, VCTS are
possible at the TJSJ,TJMZ,TJSJ and TJPS between 18Z-22Z as TSRA are
forecast to develop over the Cordillera Central. Brief MVFR conds
can`t ruled out this afternoon if storms drift briefly over the
terminals. Light winds of 10 knots or less are expected below
FL150.

&&

.MARINE...Hurricane Leslie, about 1050 miles north northeast of
TSJU is still the dominant influence on marine conditions and
will continue to produce hazardous seas in the Atlantic waters and
the passages for several more days. Currently 7 foot seas are
expected to diminish as the last high swell pass through the Mona
Passage late Sunday. 7-foot seas are not expected again through
Thursday of next week. The period will be fairly wet and there
will be scattered showers and isolated thunderstorms during most
of the period today through next Thursday.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 90 78 88 78 / 50 40 50 40
STT 87 78 87 76 / 60 60 60 50

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
448 AM AST Fri Oct 5 2018

.SYNOPSIS...A wet pattern will continue across Puerto Rico and the
U.S. Virgin Islands. Moisture and shower activity will increase
this weekend, next week and into the following weekend with mostly
cloudy skies throughout. Upper level divergence will also enhance
thunderstorm activity.

&&

.SHORT TERM...Today through Sunday...

Cloudy skies prevailed overnight and early this morning across the
forecast area with scattered to numerous showers and isolated
thunderstorms observed mainly over the surrounding waters. Coastal
temperatures were in the mid to upper 70s under east southeast winds
at 10 mph or less.

Trofiness aloft will continue to prevail through the forecast cycle
with an upper low developing northwest of the area by Sunday. As a
result, divergence aloft as well as enhanced moisture transport will
continue across the forecast area today and into the upcoming
weekend. At lower levels, light east southeast winds to continue,
becoming moderate by Sunday.

Under the aforementioned pattern, there is a high chance for periods
of showers and thunderstorms across the local islands. Continue to
expect passing showers with isolated thunderstorms across the US
Virgin Islands and eastern Puerto Rico at times as well as
thunderstorms developing over and north of the Cordillera Central
and Sierra de Luquillo each afternoon. Although cirrus clouds will
continue to stream from the west, a deepening upper level low over
the southwest Atlantic will also increase the instability, therefore
induced shower and thunder activity is still expected each day.

The risk for urban flooding and sharp rises along small streams and
rivers as well as mudslides in areas of steep terrain continues.

.LONG TERM...Monday through Friday...
Low pressure at 700 mb will form just north of the area and will
continue to bring moisture out of the Caribbean and across the
area. Moist flow will also continue to stream in from the tropical
Atlantic at lower levels, while upper levels are supplied with
moisture from thunderstorm activity to the west developing in
other lows. This will keep precipitable water values at or above 2
inches for the entire period except for a brief period on Monday.
With 500 mb temperatures varying little, instability will continue
in moderate amounts throughout the period making thunderstorms
over the area likely during the day over Puerto Rico and at least
isolated everywhere else even at night. Urban and small stream
flooding is likely from this activity. As terrain becomes
saturated, mudslides are possible and even some rivers could
overflow their banks.

&&

.AVIATION...Periods of MVFR conds will remain possible at all TAF
sites in SHRA/TSRA today, but particularly at JMZ/JBQ and possibly
JSJ aft 05/16z. Mountain obscurations are also anticipated across
the local islands. East southeast winds at around 10 knots with some
sea breeze variations are expected aft 05/13z. Max winds WNW arnd
50 kt around FL470.


&&

.MARINE...Seas are slowly returning to normal as Tropical Storm
Leslie wanders in the central western Atlantic and slowly loses
strength. Once small craft advisories come down tonight, they are
not expected to be necessary for the rest of the week.
Nevertheless seas will be close to 6 feet in exposed areas and
confidence is fairly low that they will not be needed later next
week.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 87 76 86 76 / 50 40 70 60
STT 87 76 88 77 / 70 70 60 60

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
449 AM AST Sat Oct 6 2018

.SYNOPSIS...A wet pattern will continue across the area through
the next 7 days. Surface flow will increase as high pressure
fills in north of the area early next week. Showers and
thunderstorms will bring areas of urban and small stream flooding
and occasionally rapid rises on area rivers and the threat of
mudslides in steep terrain.

&&

.SHORT TERM...Today through Monday...
A wetter pattern is progged to remain over the next several days
as a result of mid to upper level moisture lifting across Puerto
Rico and the local islands. Analysis of the SJU-GFS skew-t depicts
an unstable profile for the local area with winds veering with
height, as well as southerly winds at the surface and mid levels.
These southerly winds will continue to usher in a rich tropical
airmass, which is conducive for showers and thunderstorms during
the afternoon.

Model guidance indicates several jet streaks will pass to the north,
and south of Puerto Rico which will help shower and thunderstorm
development through Monday. Additionally, modest divergence aloft
is forecast during the afternoon across the Atlantic and
Caribbean waters, as well as portions of eastern and western
Puerto Rico through Monday.

Showers are forecast to develop across the U.S. Virgin Islands,
Culebra, St. Croix and eastern areas of Puerto Rico during the
morning hours, then showers are forecast to move over the
interior, and western Puerto Rico during the afternoon. Rainfall
amounts will range from 1 to 2 inches with higher amounts likely
in isolated areas of Puerto Rico. Therefore, the previous day`s
rainfall combined with this additional rainfall could cause urban
and small stream flooding, rapid river rises, mudslides and
ponding of water this weekend into early next week. One limiting
factor for thunderstorm development will be mid to upper level
clouds, that could disrupt daytime heating across the area. GFS
skew-t is showing a saturated profile from 500 to 150 mb, but at
this time the thinking is that some breaks in the clouds will
allow enough heating for isolated thunderstorm development.

.LONG TERM...Tuesday through Saturday...
Low pressure at 700 mb will form just northwest of the area on
Monday and will continue to bring areas of moisture out of the
Caribbean and across the area Tuesday through Wednesday. A second
low may also form southwest of Puerto Rico and move north toward
the southwest corner of the forecast area, bringing a second surge
of moisture on Thursday that will continue through the weekend.
This will keep precipitable water values above 1.9 inches for the
entire period. With 500 mb temperatures varying little, (the cool
core of the lowest temperatures will remain under the TUTT almost
1000 miles east northeast of San Juan) instability will continue
in moderate amounts throughout the period making thunderstorms
over the area likely during the day over Puerto Rico and at least
isolated everywhere else even at night. Urban and small stream
flooding is likely from this activity--especially on Wednesday and
Saturday. As terrain becomes saturated, mudslides are possible
and even some rivers could briefly overflow their banks.

&&

.AVIATION...VFR at all TAF sites now. SHRA/TSRA will dvlp from TJSJ
east by 06/15Z, then SHRA/VCTS will dvlp across interior, and
wrn areas of PR--TJMZ/TJBQ by 06/16Z. SHRA/VCTS could briefly
reduce vsbys to MVFR/IFR at TJSJ/TJBQ/TJMZ/TIST/TISX this aftn.
SHRA/VCTS to diminish by 06/23Z. Sfc winds will cont from the ESE
at 10 knots with hir gusts near SHRA/TSRA, bcmg calm or light and
vrbl aft 05/23z.


&&

.MARINE...


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 86 76 88 77 / 90 40 70 40
STT 88 77 88 79 / 70 70 70 40

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
521 AM AST Sun Oct 7 2018

.SYNOPSIS...Moist conditions continue today, ease off ever so
slightly Monday and Tuesday and then return late Tuesday and
Wednesday. Moisture dips again through Friday night. Trade wind
flow increases today and Monday. The proximity of a TUTT low will
enhance shower and thunderstorm activity through the week.

&&

.SHORT TERM...Today through Tuesday...

Minor changes in the short-term forecast as surface winds will be
out of the east to southeast instead of the southwest. This change
in wind direction will also change the location of the heaviest
rains across the areas. Recent guidance shows the mid to upper
levels are slightly drier than yesterday, as a result of the wind
change. Skew-T and model guidance still depicts a saturated
atmosphere at the mid to upper levels today through Tuesday.
Therefore mid to upper level clouds will remain across most of the
region over at least the next several days.

At the upper levels of the atmosphere a cut off low to the
northwest will advect moisture across the northwestern local
waters and northwestern areas of Puerto Rico today. In addition,
a TUTT is progged to deepen to the northeast of the region today
and meander over the next several days. As a result of these two
upper-level features, weak ridging at the upper levels currently
presides over the area. At low to mid levels a ridge of high
pressure will remain to the east of the islands, promoting south
to southeast wind flow.

The heaviest rain is forecast to be over the northwestern, and
northern areas of Puerto Rico; with rainfall amounts ranging from
1 to 2 inches with higher amounts in isolated locations.
Elsewhere, showers and isolated thunderstorms are possible as a
result of local and diurnal effects, during the mid morning to
the afternoon through Tuesday. There is a possibility for rapid
river rises, mudslides, urban and small stream flooding as a
result of todays rains combining with the effects of rains over
the past several days.

.LONG TERM...Wednesday through Sunday...
The high pressure at the surface, broadens, weakens and shifts
east southeast through Saturday and trade winds flow slowly shifts
to the east southeast. Moisture peaks on Wednesday morning and
then slowly declines from around 2.1 inches to 1.8 inches of
precipitable water. In any case both values are fairly wet and
this bodes well for continued wet weather through the period. Also
many areas of upper level divergence shift through the area to aid
convection. Winds will diminish at lower levels as the week draws
to an end and this will allow some showers and thunderstorms to
linger spreading heavy rain across the area. Urban and small
stream flooding and unstable hillsides will continue to be a
concern throughout the period.

&&

.AVIATION...VFR conds are currently observed across all terminal
sites although a high overcast will continue. SHRA/VCTS are
forecast to develop across the western areas of Puerto Rico by
07/15z and remain through 07/22Z, these SHRA/VCTS could cause
brief MVRF conds due to heavy rainfall and low CIGS. The surface
winds will continue from the east- southeast at 10- 15 knots with
higher gusts. Maximum winds NW 20-40 kt btwn FL390-500.

&&

.MARINE...Seas in the local waters have subsided, but Tropical
Storm Leslie continues to churn in the west central Atlantic
sending swell from the north northeast into the northern part of
the outer Atlantic waters and making small craft advisories
necessary. Seas at buoy 41043 have been running 7-8 feet and this
swell is moving into the local waters. Models are indicating that
these conditions will last through Tuesday.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 86 76 88 77 / 50 50 70 50
STT 87 77 88 78 / 60 60 40 30

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
516 AM AST Mon Oct 8 2018

.SYNOPSIS...

Moist conditions are forecast to continue early this week, but
pockets of drier air will also move through periodically behind
the moisture. Next weekend an increase in moisture is forecast as
a result of a tropical, wave that will move well south of Puerto
Rico. This wave will move into western Caribbean and interact with
a mid level low at 700 mb. These features will pull moisture out
of the Caribbean waters, and across the local and outer waters as
well as portions of Western Puerto Rico.

&&

.SHORT TERM...Monday through Wednesday...
High pressure at the surface moves into the western Atlantic
traveling southeast and continues to fade. This will maintain gentle
to moderate trade wind flow across the area. Moisture remains high
across the area today with precipitable water values holding above 2
inches today. Moisture values sag somewhat Tuesday and again on
Wednesday as east winds bring slightly less moist air across the
area out of the high in the western Atlantic at surface through at
least the 700 mb level. Nevertheless, the chances of showers and
thunderstorms across the area will remain quite high as instability
of minus 6 is expected by the GFS each afternoon in SJU. Also mid
and upper level cloudiness should diminish somewhat to deliver more
destabilizing sunshine to the area. Although Wednesday is not quite
as favorable regarding upper level divergence, convection should be
enhanced somewhat today and Tuesday as weak upper level ridging
remains between the southern periphery of the TUTT to the east
northeast and its satellite low just north of the windward passage
by Tuesday. The bottom line is that local urban and small stream
flooding is possible each day with showers and thunderstorms.
Pockets of frequent lightning may be seen in the afternoons.

.LONG TERM...Thursday through Monday...
A surface ridge of high pressure is forecast to maintain its hold
over the region through the long-term period with prevailing
easterly winds. At the upper levels weak areas of low pressures
are progged to develop to the north or northwest of the Puerto
Rico. A weak tropical wave is forecast to move south of Puerto
late Sunday or early Monday, and interact with a mid level low at
700 mb. Patches of moisture are forecast to lift out of the
Caribbean and move into the local and offshore waters. Therefore,
a wetter pattern is expected to continue through the long term
period as a result of deep tropical moisture, and local diurnal
effects. However, pockets of drier air are also forecast to move
through the area periodically during the period.

&&

.AVIATION...The potential for SHRA/TSRA is high this afternoon across
the flying area. VCSH is expected across the local terminals.
+SHRA/TSRA could result in brief periods of MVFR or even IFR
conditions mainly at TJMZ/TJBQ/TJSJ. SHRA/VCTS are forecast to
diminish across the region by 08/23Z. The surface winds will
continue from the east-southeast at 10-15 knots with higher gusts
in/near SHRA/TSRA, becoming light and dominated by land breezes
aft 07/23z. Maximum winds FL460 NW 25 kt.


&&

.MARINE...
Seas will range from 4 to 5 feet today across most of the local
and outer waters. Small craft are urged to exercise caution due
to seas occasionally reaching 6 feet. Winds will be out of the
east to southeast at 10 to 15 kts. Small craft advisories are not
expected this week.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 78 88 78 87 / 50 70 70 60
STT 81 85 81 85 / 50 60 60 50

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
411 AM AST Tue Oct 9 2018

.SYNOPSIS...

A surface ridge of high pressure will continue to promote easterly
winds across the region through the weekend. Showers and isolated
thunderstorms are possible as a result of lingering moisture from
a tropical wave that will move out of the area later today, and
local and diurnal effects. A mid to upper level low is forecast to
develop to the southwest of Puerto Rico in the Caribbean waters,
and swing deep tropical moisture periodically across the western
local waters and western areas of Puerto Rico during the weekend.
Therefore, the weekend looks to be unsettled but this depends on
how much drier air will filter in periodically during the
weekend, which could limit shower and thunderstorm development.

&&

.SHORT TERM...Today through Thursday...

Residual moisture associated with a tropical wave located near
Hispanola this morning will remain over the area for today with
precipitable water values around 2.00 inches expected. Despite the
high moisture content in place, there is a high degree of
uncertainty in terms of the rainfall activity expected for today
as mid to high level cloudiness will continue to linger over the
area during the morning hours, limiting the diurnal heating and
therefore the destabilization to allow for shower and
thunderstorm activity to materialize. Nevertheless, if enough
diurnal heating occurs then expect showers and thunderstorms to
develop during the afternoon hours, mainly across the northwest
quadrant of PR with more isolated activity possible across eastern
PR and the USVI. Given that the soils remain saturated from the
rainfall from the past several days, any additional heavy rainfall
could create urban and small stream flooding as well as mudslides
in areas of steep terrain.

On Wednesday and Thursday, improving weather conditions are expected
across the local area as a drier airmass moving in from the
northeast will erode the deep moisture content that has been upon us
for the last several days. Therefore, a more seasonable weather
pattern is expected with some brief passing showers across eastern
PR and the USVI during the overnight and early morning hours
followed by the development of locally and diurnally induced shower
and thunderstorm activity across western PR during the afternoon
hours.

&&

.LONG TERM...Friday through Tuesday...

A surface ridge of high pressure is progged to build to the north
of the region and hold through the long-term period and shift west
later this week. The surface ridge of high pressure will result in
easterly winds across the area through Monday.
Model guidance shows a weak area of low pressure meandering to
the north of Puerto Rico through the weekend. The GFS and ECMWF
continue to show a weak tropical wave moving across the southern
Caribbean waters on Sunday. This moisture will increase
instability as well as showers and isolated thunderstorms across
the western and interior areas of Puerto during the afternoon. The
moisture from the wave will continue to progress to the west of
Puerto Rico, then interact with the mid to upper level trough
that is forecast to develop in the western Caribbean during the
weekend. Therefore unsettled weather conditions are forecast to
continue through early next week. Although, moist conditions are
progged pockets of drier air will move in periodically from the
east across the forecast area.

&&

.AVIATION...

The potential for SHRA/TSRA activity will continue to remain high
across flying area. +SHRA/TSRA expected to develop across the
northwest quadrant of PR btwn 09/16-22z. This could briefly create
MVFR or even IFR conditions across TJMZ and TJBQ terminals.
SHRA/TSRA expected to diminish across western PR after 09/23Z. VCSH
will continue across eastern PR, the USVI, and leeward islands
terminals through 10/04z. The surface winds will continue from the
east southeast between 10 and 15 knots with sea breeze variations
after 09/14z.

&&

.MARINE...

Seas will range from 4 to 6 feet across the Atlantic waters and
Caribbean passages today. Therefore small craft operators are
urged to exercise caution due to choppy seas. Elsewhere, seas are
will range from 3 to 5 feet with winds ranging from 10 to 15 kts
with higher gusts possible. Another surge of northerly swell
associated to Leslie will reach our local Atlantic waters between
Wednesday night and Thursday morning. There is a high rip current
risk for the northern beaches of Puerto Rico and northern beaches
of Culebra.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 88 78 87 78 / 50 50 20 50
STT 85 81 85 81 / 50 50 20 50

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
521 AM AST Wed Oct 10 2018

.SYNOPSIS...A slightly drier airmass will reduce the rainfall
coverage during the day today through early Thursday. A wetter
and more unstable weather pattern is expected starting later on
Thursday and continuing into the early portions of next week as
an upper-level low will combine with deep tropical moisture
associated with a developing surface low-pressure area and also
from a tropical wave that will be moving from the east.

&&

.SHORT TERM...Today through Friday...

The available moisture will decrease somewhat through the day today,
particularly for the northern portions of the forecast area. There
is also an upper ridge over the local area today, but an upper
trough will gradually develop to the west of the local area by
Friday, which will gradually dig to the west southwest for the next
couple of days after that. Even though moisture will decrease
slightly this afternoon, there will still be enough moisture that
will combine with the local effects to cause the development of
showers and thunderstorms across the interior, western and
southwestern PR this afternoon. There is also a chance of showers
across eastern Puerto Rico and the northern USVI.

Even though the upper trough is expected to develop by Friday to the
west of the local area, the chances of thunderstorm continues in the
short term. Not to mention the fact that the available moisture will
start to increase once again on Thursday afternoon and we will
continue to have higher than normal moisture on Thursday afternoon
and Friday and for the next several days after that, with
precipitable water values near 2 inches. So given the current setup,
we expect a somewhat rainy pattern for the next few days, with the
thunderstorms mainly in areas of convergence, such as sea breeze
convergence and also downstream from the islands and the Luquillo
Mountain Range into the San Juan metro area, especially for Thursday
and Friday. Little change in the temperatures is expected, with the
max temps in the mid to upper 80s across the lower elevations and in
the low 80s across the higher elevations.

.LONG TERM...Saturday through Thursday...

The wet and unstable weather pattern will prevail across the
region during the weekend into early next week as the upper-level
trough, which will be situated north of the region, will combine
with deep tropical moisture not only associated with a developing
surface low-pressure area over the central Caribbean, but also from
a tropical wave that will be moving in into the forecast area
late Sunday into Monday. This will provide a favorable environment
for enhanced shower and thunderstorm activity across the forecast
area during this time period.

A return to drier weather conditions is expected by the middle to
latter half of next week as a drier airmass will be moving in from
the northeast, therefore, limiting the shower activity.


&&

.AVIATION...
VFR conds expected across the local terminals through 10/17Z, due to
SHRA/TSRA possibly affecting TJMZ thereafter. However there will be
SHRA in the general area that may cause VCSH across most of the
local terminals through the forecast period. Winds will be mainly
from the east to ENE at 15KT and gusty with sea breeze variations
past 10/14Z.


&&

.MARINE...Seas will continue to range between 4 to 6 feet across
the Atlantic waters and local Caribbean passages. Therefore, small
craft operators are urged to exercise caution across these waters.
Elsewhere, seas of 3 to 5 feet are expected to prevail. Northerly
swell associated with Hurricane Leslie, located across the
central Atlantic Ocean, will continue to produce a high risk of
rip currents across the northern beaches of PR and Culebra for
today.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 87 79 90 79 / 40 20 60 40
STT 91 81 87 81 / 40 20 50 40

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
449 AM AST Thu Oct 11 2018

.SYNOPSIS...Upper-level trough will become situated near the
region during the next several days and will combine with a deep
plume of tropical moisture to result in an unsettled weather
pattern through early next week. Improving weather conditions
expected by the latter half of next week as a drier airmass moves
in from the east.

&&

.SHORT TERM...Today through Saturday...

The available moisture will gradually increase from the south as the
day progresses. There is also an upper trough that is developing to
the west of the local area as it erodes the upper ridge. The upper
trough will continue developing for the next few days, which will
gradually dig to the west of the local area. The moisture advection
expected today will combine with the local effects, diurnal heating
and the improving upper level divergence to cause the development of
showers and thunderstorms this afternoon across many sectors of
Puerto Rico, especially western PR and the eastern third of the
island. Elsewhere, scattered showers with isolated thunderstorms are
expected. Even though the upper trough is expected to be in a much
more favorable position by Friday, the high resolution models,
particularly the WRF is rather bullish with the amount of rainfall
and thunderstorm potential today.

The increase in moisture will continue on Friday and for the next
several days after that, with precipitable water values near 2
inches. However, the high resolution models are insisting that
Friday will not have as much rainfall as today, this could be given
to the layer of cloudiness that is expected, which may limit
convection to a few areas, likely to the northern and northwestern
sections of PR, with shower and thunderstorm activity increasing
late in the afternoon and into the evening as the upper trough
positions itself in a better location to produce favorable dynamics
for thunderstorm development over the local area into Saturday. This
means that Saturday could be a day with numerous showers and
scattered thunderstorms. At this time there is very little to suggest
the contrary. The upper trough will be in a good location, there
will be plenty of moisture, and there will be divergence in the
upper levels. At this time, it looks like Late Friday into Saturday
could be have numerous showers and some thunderstorms from late
Friday into Saturday. No change in the temperatures is expected for
today, with the max temps in the mid to upper 80s across the lower
elevations and in the low 80s across the higher elevations.

.LONG TERM...Sunday through Friday...

Upper-level trough will continue to be situated near the local
area through early next week, providing favorable upper-level
dynamics and decent instability aloft. This trough in combination
with the deep plume of tropical moisture expected to envelop the
region through the southeasterly wind flow will create a favorable
environment for the development of shower and thunderstorm
activity across the forecast area through at least Tuesday.
However, a caveat for the potential for heavy rainfall each day
throughout the period is the amount of mid to upper-level
cloudiness that could potentially be present. If there is enough
cloudiness to limit diurnal heating and therefore the instability,
then rainfall activity could be limited across the region each
day. This is something that will have to be monitored during the
next several days. Nevertheless, if the heavy rainfall does indeed
materialize then there will be an increased potential for urban
and small stream flooding as well as mudslides in areas of steep
terrain.

A drier weather pattern is expected during the latter half of next
week as a drier airmass is forecast to move in from the east,
which will aid in decreasing the moisture content, therefore
limiting the shower activity across the forecast area.

&&

.AVIATION...Sct SHRA expected across the local area through 11/14Z,
causing VCSH at TIST and TISX. However, VFR conds expected across
the local terminals through 11/16Z, with SHRA/TSRA developing and
likely affecting the terminals or the vicinity of the terminals
in PR thereafter. Winds will be from the east to ENE at 10 to 15KT
and gusty with sea breeze variations past 11/14Z. Winds may be
slightly stronger near thunderstorms.


&&

.MARINE...Choppy seas between 4 to 6 feet will continue to prevail
mainly across the Atlantic waters, Anegada Passage, and the
offshore Caribbean waters. Therefore, small craft operators should
exercise caution across these waters. Across the rest of the
regional waters, seas between 2 and 5 feet will prevail. East
winds between 10 to 15 knots will also prevail. High risk of rip
currents continues in effect for the northern beaches of PR as
well as Cramer Park in Saint Croix.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 87 78 89 77 / 60 40 50 60
STT 89 78 89 76 / 50 40 70 70

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
433 AM AST Fri Oct 12 2018

.SYNOPSIS...Gradual increase in moisture will combine with a
developing upper trough to the west of the local area as well as
local effects to cause showers and thunderstorms, particularly in
the afternoon hours, and saturday looks particularly active.
Surface high pressure to the north-northeast of the local area
will keep a moderate east-southeast wind flow across the local
area today and on Saturday. Weak tropical wave, currently at
around 54W is expected to move through the local area late on
Sunday, likely causing modest impacts.

&&

.SHORT TERM...Today through Sunday...

Unstable conditions are expected today through the weekend across
the forecast area as the combination of abundant moisture from a
moist southeasterly wind flow and an upper-level trough located just
north of the region will result in a favorable environment for
shower and thunderstorm activity. Given that the soils are
saturated, additional heavy rains will result in urban and small
stream flooding as well as sharp water rises along larger river
basins. Mudslides in areas of steep terrain are also possible.

For today, during the morning hours, scattered showers are expected
to affect portions of eastern PR and the USVI. Then during the
afternoon time frame, locally and diurnally induced shower and
thunderstorm activity is expected across the northwest quadrant of
Puerto Rico with additional shower activity possible across the rest
of Puerto Rico and the USVI.

As it has been advertised during the last couple of days, Saturday
looks to be the day with the most widespread and heaviest activity
as a further increase in moisture content as well as plenty of
divergence aloft from the upper-level trough will result in the
development of numerous showers and thunderstorms across the local
islands and regional waters. Therefore, it seems likely that
flooding could be widespread.

Lesser rainfall coverage is expected for Sunday as the upper-level
dynamics look to be less, however, the combination of local and
diurnal effects and plenty of moisture is expected to result in
another round of afternoon convection, mainly across northwest PR.

.LONG TERM...Monday through Saturday...

Near to higher than normal moisture is still expected to linger
for the first half of the upcoming workweek, with precipitable
water values near 1.8 to 2 inches. A decrease in moisture is
expected to begin on Thursday and continue a drying trend for the
latter part of next week, that is if the long rage models are
correct. The GFS model has precipitable water values as low as
1.3 to 1.4 inches for next Friday, and even lower for Saturday,
which would be very dry for this time of year. However, the upper
levels may provide some instability as upper low and upper troughs
may be present over and to the west of the local area. These
upper level features may help in the development of showers and
thunderstorms in the afternoon hours, especially when combined
with sea breeze convergence and diurnal heating. Since this is in
the long term and the models have been somewhat inconsistent, the
confidence for the long term forecast is low.


&&

.AVIATION...VFR conditions are expected across all terminals
through 12/16z. SHRA/TSRA to develop across western and NW PR
after 12/16z with VCTS across TJMZ and TJBQ terminals, resulting
in MVFR conditions at times. Conditions to improve after 12/22z.
Sct SHRA and TSRA expected to increase in coverage after 12/22z
across eastern PR and the USVI and may affect TJSJ/TISX/TIST
terminals through the overnight. Winds will generally be from SE
between 10 to 15KT with sea breeze variations after 12/14z.

&&

.MARINE...Seas are still expected to be up to 6 feet across the
local Atlantic waters, offshore Caribbean waters and the Anegada
passage, and generally 2 to 5 feet elsewhere. Winds are expected
to be mainly from the east to southeast at 10 to 15 knots. There
is still a high risk of rip currents across the northern beaches
of PR as well as some of the beaches in north and northeastern
Saint Croix.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 88 77 87 76 / 50 60 70 60
STT 87 77 85 75 / 50 60 60 60

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
511 AM AST Sat Oct 13 2018

.SYNOPSIS...Upper trough is digging to the west of the local
area, inducing a surface trough over the area and pulling moisture
from the south into the local islands. This deep moisture with
the instability of the upper trough will cause showers and
thunderstorms across the local area today. A weak tropical wave is
expected to pass over the area late Sunday into Monday, but the
impacts are expected to be relatively modest once combined with
diurnal heating and local effects. Near or higher than normal
moisture expected for the next several days, drier air is not
expected until maybe late next week.


&&

.SHORT TERM...Today through Monday...

Unstable and humid weather conditions will persist across the local
islands today. Under a moist southerly wind flow, showers and
thunderstorms will spread from the south into the region throughout
the day. This weather conditions are due to the combination of
abundant moisture and an upper-level trough (located to the
northwest of the islands) which will result in a favorable
atmospheric conditions for the development of this activity. Soils
are already saturated and any additional persistent heavy rain will
trigger mudslides along steep terrains. In addition, urban and small
stream flooding as well as sharp water level rises along larger
river basins are likely today.

For Sunday into Monday, although model guidance are indicating above
normal PW values across the islands, shower and thunderstorm
activity should diminish somewhat early Sunday morning ahead of the
next tropical wave which is forecast to reach the islands late
Sunday into Monday. However, shower activity is expected to affect
the eastern half portion of Puerto Rico during the morning hours
followed by locally induced afternoon convection across the interior
and western sections each day. The risk of rainfall activity will be
present for much of the islands each day.

.LONG TERM...Tuesday through Sunday...

Near to higher than normal moisture is still expected to linger for
Tuesday and Wednesday, with precipitable water values near 1.8 to 2
inches. Latest guidance still indicates that a decrease in moisture
will begin on Thursday and continue a drying trend for the latter
part of next week. The GFS model has precipitable water values as
low as 1.3 to 1.4 inches for next Thursday night into Friday, with
such values hanging around near 1.4 inches on Saturday and Sunday
but with brief periods of drier and wetter patches. The upper levels
may still provide some instability as upper low pressure and upper
troughs may be present over and to the west of the local area.
Therefore, even with drier conditions, there may still be some
showers and thunderstorms in the afternoon hours, especially in
areas of sea breeze convergence combining with diurnal heating and
local effects.

&&

.AVIATION...SHRA/TSRA expected to affect TIST/TISX through at least
13/12z. This activity will spread across mainland PR by mid
morning and into the interior, west and north PR after 13/15z.
VCTS expected across TJMZ, TJBQ/TJSJ/TJPS. Afternoon activity
expected between 13/15-22z and could produce MVFR conditions at
times. Conditions are expected to improve by 13/23z, but
-SHRA/SHRA will remain possible. Surface winds will continue from
the SE btwn at 10 kt or less, increasing at 10-15 kt with sea
breeze variations and gusty conditions in/near SHRA/TSRA.


&&

.MARINE...Seas are expected to be generally between 3 and 5 feet
across the local waters, except the nearshore waters of western and
southern Puerto Rico where 1 to 3 feet are expected. There is a high
risk of rip currents for the north coast of Puerto Rico and Cramer
Park in Saint Croix through this afternoon.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 86 76 87 77 / 70 60 50 50
STT 84 76 87 78 / 80 60 50 50

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
513 AM AST Sun Oct 14 2018

.SYNOPSIS...Upper trough with axis to the west of the local
area will combine with the available moisture and diurnal heating
for another round of showers and thunderstorms across western and
central PR this afternoon. A rather weak tropical wave is
expected to pass over the area late tonight into Monday, but the
impacts are expected to be relatively modest since it appears to
have flattened as it combined with the upper trough and induced
surface trough. Near or higher than normal moisture is expected
for today through Tuesday, somewhat drier air may start to filter
in late Wednesday, and even drier air could start to move in late
Thursday into next weekend.

&&

.SHORT TERM...Today through Tuesday...

Although tranquil weather conditions will prevailed during the
morning hours, a few light passing showers can not be ruled out
across the Caribbean waters. Some of these showers will move inland
over the U.S. Virgin Islands, the east and southeast sections of
Puerto Rico through the morning hours. During the afternoon hours,
the upper level trough will combined with a moist east-southeast
wind flow, surface convergence and diurnal heating to result in
another round of thunderstorms with periods of moderate to heavy
showers along the interior and north of the Cordillera Central of
Puerto Rico. The risk for mudslides along steep terrains as well as
sharp water level rises along rivers and theirs tributaries is high
especially in areas with the heaviest showers.

A weak tropical wave, which seems to have lost their tropical
characteristics, is expected to reach the islands by late tonight
into Monday. Vorticity is forecast to increase across the U.S.
Virgin Islands and eastern PR by early Monday morning, increasing
the the potential for showers and thunderstorms across these areas.
Then, the maximum values in the vorticity were suggested to spread
across mainland PR by the afternoon hours. As a result, the
potential for precipitation continues high across the islands.

Easterly winds are forecast to return as a surface high pressure
amplifies across the Central Atlantic Ocean. Abundant moisture as
well as high chance for rainfall activity will continue through at
least Tuesday.

.LONG TERM...Wednesday through Monday...

Slightly drier air is expected to start moving in late Wednesday,
but the precipitable water values may still be near the normal
levels for this time of year. The long range models insist that a
more significant decrease in moisture will begin on Thursday and
continue the drying trend through the next weekend. Having said
that, the model shows brief moments, such as patches of higher
moisture through the latter part of the week. The upper levels may
still provide some instability as an upper trough may be present
to the west of the local area on Wednesday, but eroding, as
another upper trough develops to the east northeast, causing
subsidence starting on Thursday. Therefore, any significant
shower and thunderstorm activity that may develop in the afternoon
hours across PR should be in areas of sea breeze convergence as
it combines with diurnal heating and local effects, the rest of
the areas should observe brief showers, if any.


&&

.AVIATION...VFR conditions will persist through at least 14/16z
when SHRA/TSRA are expected to form across the interior and
northern sections of Puerto Rico. This may result in MVFR
conditions at TJBQ/TJMZ/TJSJ between 14/16-23z. A weak tropical
wave is forecast to reach the islands after 15/00z. At the
surface, winds will continue from the ESE at 10 kt or less,
increasing at 10-15 kt with sea breeze variations and higher gusts
in/near SHRA/TSRA.


&&

.MARINE...For today, seas are expected to be between 3 and 5 feet
across most of the local waters, except the nearshore waters of
western and southern Puerto Rico where 1 to 3 feet are expected.
There is a moderate risk of rip currents today for the north
coast of Puerto Rico and the north and east beaches of Saint
Croix.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 87 76 88 77 / 30 50 50 40
STT 87 77 87 79 / 30 50 50 40

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
438 AM AST Mon Oct 15 2018

.SYNOPSIS...Unstable conditions are expected to continue through
at least Tuesday as an upper-level trough now located west of the
local area will combine with above normal moisture increasing the
shower and thunderstorms coverage across the local region.high
pressure will settle in across the western Atlantic by Wednesday
decreasing the chances of shower activity for the incoming
weekend.

&&

.SHORT TERM...Today through Wednesday...

As it has been forecasted, showers and thunderstorms affected the
eastern sections of Puerto Rico and the U.S. Virgin Islands
overnight as a tropical wave reached the islands. Early this
morning, moderate to heavy rainfall was observed across the eastern
third portion of Puerto Rico. This tropical wave will continue to
bring shower and thunderstorm activity across these locations
through the morning hours. Then, they will spread across the
interior and western sections of mainland of Puerto Rico by late
this morning into the afternoon hours. Although the intensity of the
showers and thunderstorms should diminish around sunset, some of
this activity may linger across the windward sections of PR/USVI
late tonight into Tuesday morning.

Keep in mind that given the rainfall activity that has been observed
during the past week, soils still saturated and the risk for
mudslides along steep terrains as well as sharp water level rises
along rivers and theirs tributaries is high especially in areas with
the heaviest showers.

East to northeasterly winds will return through the rest of the week
as a surface high pressure amplifies across the Central Atlantic
Ocean. An upper level trough and high moisture content will keep
high the chance for rainfall activity through at least mid-week.

.LONG TERM...Thursday through Tuesday...
After mid week a mid to upper- level ridge pattern will settle in
across the western Atlantic through this weekend limiting the
showers and thunderstorms across the local forecast area. During
this forecast period winds will have a more Northeast component
therefore the afternoon convective activity will be focus over the
southwest portion of Puerto Rico. Also this wind direction will
maintain temperatures below normal. Moisture is expected to once
again slowly increase after Tuesday.


&&

.AVIATION...A tropical wave will increase SHRA/TSRA across the local
flying area today. Expect SHRA/TSRA across E-PR/USVI through the
morning hours. VCTS with brief +SHRA expected at TJSJ through the
morning hours. SHRA/TSRA will spread across the interior and
western sections between 15/15-23z. This may result in MVFR
conditions at TJBQ/TJMZ/TJSJ. At the surface, winds will continue
from the E at less than 10 kt but gusty in/near SHRA/TSRA. Winds
are forecast to increase at 10-15 kt with sea breeze variations
aft 15/13z.


&&

.MARINE...Mariners should continue to experience showers and
thunderstorms across the local watersthrough at least mid morning.
Some of these showers and thunderstorms would also generate gusty
winds and choppy seas. Winds are expected to increase later today
therefore mariners should also expect an increase on seas up to 7
feet in some of the marine zones, mainly across the Caribbean and
Atlantic waters. There will a pulse of a moderate north-northwest
swell on Saturday night through Sunday morning.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 88 79 87 78 / 60 40 60 60
STT 87 78 88 79 / 60 40 60 60

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
509 AM AST Tue Oct 16 2018

.SYNOPSIS...Unstable conditions are expected through early
Wednesday due to lingering moisture and a TUTT/trough to the
northwest of the Puerto Rico. A tropical wave is forecast to move
across the local region between Wednesday and Thursday increasing
winds and showers coverage across the local islands. After this
wave moves away a low and mid- level ridge will hold across the
region with drier air filtering in out of the east. This will
limit shower and thunderstorm development to the eastern, interior
and western portions of Puerto Rico during the afternoon.

&&

.SHORT TERM...Scattered to numerous showers were detected across the regional
waters and some of them moved inland across the U.S. Virgin Islands,
north and east Puerto Rico overnight. There is good chance to
observe additional passing showers across these sections through the
morning hours due to deep moisture across the region. The rest of
Puerto Rico had mostly clear skies with no rainfall activity. Under
a northeasterly wind flow pleasant morning temperatures were
registered across the isles early this morning.

Instability associated to a tilted upper level trough has diminished
but there is still enough moisture to result in locally scattered
brief showers through the morning hours. These factors combined with
diurnal heating and local effects will aid in the development of
showers and thunderstorms especially across central and western PR
with some across eastern PR and the San Juan metro area.

Plenty of tropical moisture will continue Tuesday night into
Wednesday early morning, which combined with surface convergence
will result in shower and thunderstorm activity across the
surrounding waters of the U.S. Virgin Islands and E-PR. Another
tropical wave is expected to move closer to the islands Wednesday
into Thursday to keep a high chance for rain and squally weather
through at least Thursday afternoon. There is some uncertainty in
the timing of the arrival of Thursday dry air. That`s why we went
with a conservative forecast, because the weather will be associated
to the arrival of this air mass.

.LONG TERM...Friday through Wednesday...
A mid to upper-level ridge will hold across the region through
the long-term period with low level moisture periodically working
in from the east as well as drier air. As a result of limited
moisture and instability showers and thunderstorms developed will
be limited to the northern, western and interior areas of Puerto
Rico during the afternoon. Below normal temperature are expected
to prevail through the weekend as winds will remain from the
Northeast. Winds will shift to a more easterly component after
Tuesday and moisture is also expected to slightly increase.

&&

.AVIATION...VFR conds will persist through at least 16/15Z, but
passing -SHRA and SHRA will move across the terminals of
E-PR/USVI/Lesser Antilles through the morning hours. SHRA/TSRA
will develop across the interior and western sections of PR
between 16/15-23z to affect TJMZ and the vicinity of
TJSJ/TJBQ/TJPS. ENE winds at 10 to 15 knots with higher gusts and
sea breeze variations are expected across the flying area after
16/12z.

&&

.MARINE...Mariners should exercise caution today across most the
local waters with winds of between 15 to 20 knots and seas up to 6
feet. Tonight a small craft advisory will be in effect as an
approaching tropical wave will increase the seas up to 7 feet
mainly over the Atlantic off shore waters and the Anegada Passage.
there is a chance for squally weather conditions late tonight as a
Tropical wave moves across the area through Wednesday.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 86 77 87 79 / 50 80 60 60
STT 88 79 88 78 / 50 80 60 60

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
353 AM AST Wed Oct 17 2018

.SYNOPSIS...Unstable conditions are expected through early
Thursday as a tropical wave is forecast to move across the local
region between Wednesday and Thursday increasing winds and showers
coverage across the local islands. After this wave moves away a
low and mid- level ridge will hold across the region with drier
air filtering in out of the east. This will limit shower and
thunderstorm development to the eastern, interior and western
portions of Puerto Rico during the afternoon.


&&

.SHORT TERM...Showers have persisted across portions of the USVI
and across much of the eastern and northern half of Puerto Rico.
Around half an inch of rain was observed with the heaviest
showers. A mid level high pressure across the western Atlantic
that extends into the northeastern Caribbean will continue to
promote breezy east to northeast trades across the region during
the next few days. Somewhat cooler temperatures are expected under
the northeast wind flow.

An active tropical wave is currently moving across the Leeward
islands and is forecast to cross the region through the evening
hours. An upper level low is forecast to linger today over
Hispaniola while moving slowly westward, providing some divergence
aloft over the region. These two features will result in scattered
to numerous showers and thunderstorms through the evening hours
across the forecast area. This activity will result in urban and
small stream flooding.

.LONG TERM...Saturday through Thursday.
A mid to upper-level ridge will hold across the region through
the long-term period with low level moisture periodically working
in from the east as well as drier air. As a result of limited
moisture and instability showers and thunderstorms developed will
be limited to the northern portion of Puerto Rico during the
morning hours, and southwest areas of Puerto Rico during the
afternoon. Below normal temperature are expected to prevail
through the weekend as winds will remain from the Northeast. Winds
will shift to a more easterly component after Tuesday and
moisture is also expected to slightly increase.

&&

.AVIATION...SHRA expected with approaching tropical wave today
across most of the terminals. Iso TSRA possible across the
USVI/Eastern PR terminals through the morning hours. Afternoon
SHRA/TSRA mainly expected over the interior and southwestern
quadrant of PR. Tempo MVFR conds and mtn top obscd are expected with
SHRA today. Breezy ENE winds between 15-25 kt expected to prevail.


&&

.MARINE...Seas will continue on the range of between 5 to 7 feet
and winds on the range of 15 to 20 knots with an occasional
stronger gusts. This pattern will generate choppy and hazardous
conditions therefore a small craft advisory is in effect for the
offshore Atlantic waters and Caribbean waters. Shower and
thunderstorm coverage is expected as a tropical wave moves across
the Caribbean waters through Thursday morning.



&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 87 78 87 78 / 60 40 40 30
STT 88 79 88 78 / 60 50 50 30

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
440 AM AST Thu Oct 18 2018

.SYNOPSIS...Mid to upper level ridge will dominate the weather
conditions through next week. Moderate to fresh northeast winds
will prevail for the next several days. Trade wind showers will
continue to move at times over the regional waters and into
portions of the USVI and north/east PR. Diurnally induced
afternoon showers are expected mainly to develop over
southwestern PR.


&&

..SHORT TERM...Today through Saturday...

Partly cloudy skies prevailed across the forecast area overnight and
early this morning with frequent passing showers observed across the
northern USVI, eastern Puerto Rico as well as the surrounding waters.
However, rainfall accumulations associated with these showers were
minimal. Winds were from the east at 10 mph or less with coastal
temperatures in the mid to upper 70s.

Mid level ridge across the western Atlantic is expected to extent
across the northern Caribbean isles and hold through at least the
upcoming weekend. This feature will erode available moisture as soon
as today with PW values near or below the normal range. At lower
levels, a moderate to fresh east northeast wind flow will continue
to prevail through the forecast period. A tropical wave in the
vicinity of the Mona Passage, will continue to move west and away
from the local region throughout the day.

Under ridge pattern and eroding moisture, expect fair weather
conditions across most of the local islands. However, locally
induced showers are still possible across western areas of Puerto
Rico each afternoon. East northeast winds will continue to promote
maximum temperatures in the mid to upper 80s along coastal areas.
The chance for isolated thunderstorms will return on Saturday
afternoon.

.LONG TERM...Sunday through Friday...

A mid to upper level ridge across the western and central
Caribbean will continue to promote drier air aloft through the
long term period. Upper level trough and induced perturbations are
expected to remain to the east/northeast of the region. Under a
northeasterly wind flow, passing trade wind showers are expected
to continue across the USVI and across the northeastern sections
of PR through next week. Followed by limited afternoon convection
over the southwestern quadrant of PR. A short wave trough is
forecast to move over the area on Thursday, this should enhance
afternoon shower and thunderstorm activity over the Cordillera
Central. Normal to below normal temperatures are forecast to
continue during the long term period. Moderate to fresh northeast
trades are expected to prevail through midweek, becoming light to
gentle during the second part of the workweek.


&&

.AVIATION...VFR conds are expected to prevail at all TAF sites
with a few -SHRA in and around the Leeward and USVI terminals as
well as JSJ in the morning. Aft 18/16z VCSH likely at JMZ. ENE
winds at around 15 knots with some sea breeze variations.


&&

.MARINE...A small craft advisory is in effect for the offshore
Atlantic and Caribbean waters, as well across the Mona Passage
through this afternoon due to seas up to 7 feet. Elsewhere, small
crafts should exercise caution due to seas up to 6 feet and east
to northeast winds up to 20 knots. There is a high rip current
risk for the northwest coast of Puerto Rico. Especially across the
beaches of Isabela.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 87 77 86 77 / 40 20 40 40
STT 88 78 88 78 / 20 20 40 40

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
518 AM AST Sat Oct 20 2018

.SYNOPSIS...Northeast trades will continue to bring showers across
the USVI and the northern and eastern sections of PR today. Light
to moderate northeast winds will prevail through early next week.
Afternoon showers are expected mainly along the south/southwestern
portions of PR each day. Mid to upper level high pressure over
the southwestern Atlantic will continue to promote dry air aloft.
A surface trough northeast of the Leeward islands will continue to
promote shallow moisture across the forecast area.

&&

.SHORT TERM...Today through Monday...
At upper levels a weak trough extending southwest from a stronger
trough to the northeast will move southeast of the area. High
pressure now over the Florida west coast at 250 mb will open up into
a weak ridge over Puerto Rico by Monday morning. At mid to lower
levels air over the local area is sandwiched between a trough
extending northeast out of Venezuela and a cold front about 370
miles north of Puerto Rico and the U.S. Virgin Islands. The air in
this channel is flowing toward the southwest over the local area and
bringing patches of mostly low level moisture that will continue to
bring persistent shallow showers across the area. A second front
will move into the western Atlantic on Sunday and reinforce this
channelized flow. Local heating and convergence will also cause
stronger showers in southwest Puerto Rico during the afternoons each
day. Although today is expected to be the wettest over all showers
could bring afternoon urban and small stream flooding to localized
areas in western and southwestern Puerto Rico today through Monday.
Shower activity will weaken on Sunday after a weak shearline moves
through at 700 mb, and will only be slightly better on Monday.

.LONG TERM...Tuesday through Saturday...

An upper level ridge will continue to promote drier air aloft
through the work week. Northeast winds will continue through
Wednesday, more easterly and lighter winds are expected through
the second part of the week, as a col area moves over the region.
Lacking upper level support, thunderstorm activity is not
expected. However, diurnally induced afternoon showers are
expected each day, over west/southwest PR early in the cycle then
along the interior and western sections of PR during the end of
the period. Low level moisture appears to increase later in the
weekend across the forecast area.

&&

.AVIATION...SHRA in NE flow to continue area wide. Brief MVFR psbl
Leeward Islands at TNCM/TKPK in SHRA otherwise VFR conds expected
all TAF sites until aft 20/17Z when passing +SHRA may lower CIGS
briefly at TJMZ or TJBQ til 21/02Z. Sfc winds NE 5 to 15 kt with
gusts to 25 kt near +SHRA. Maximum winds NNE-NE 18-25 kt btwn FL034-
300.

&&

.MARINE...Seas will range overall between 3-6 feet through the
weekend. The higher seas are expected mainly across the Atlantic
waters and passages. Northeast trades will prevail between 10-15
knots while gradually diminishing through early next week. A
moderate risk of rip currents will continue for the north facing
beaches of the islands. A high rip current risk is expected on
Sunday across the northern beaches of Puerto Rico.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 86 78 88 78 / 60 50 60 60
STT 88 78 88 79 / 30 40 40 40

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
442 AM AST Sun Oct 21 2018

.SYNOPSIS...An upper level ridge will continue to promote drier air
aloft and inhibit thunderstorm development during the next few
days. However, a northeast wind flow will continue to bring
passing showers and low level moisture across the islands through
early next week. Diurnally induced afternoon showers are expected
mostly over the southwest quadrant of Puerto Rico each day. Winds
are expected to diminish by the middle of next week and moisture
is expected to increase during the second part of the week.


&&

.SHORT TERM...Today through Tuesday...

At upper levels high pressure at 250 mb now just north of the
southeast end of the Bahama Islands will move to the Leeward Islands
by tonight and dissipate leaving the local area under light west
northwest flow. At mid to lower levels air over the local area is
sandwiched between a trough extending northeast out of Venezuela and
a nearly dissipated cold front about 400 miles northwest of Puerto
Rico and the U.S. Virgin Islands. A second front will advance into
the same area by late Tuesday. The air in this channel is flowing
toward the southwest over the local area and bringing patches of
mostly low level moisture that will continue to bring persistent
shallow showers across the area with mountain slopes receiving
better accumulations of between one half and one inch. Local heating
and convergence will also cause stronger showers in southwest Puerto
Rico during the afternoons each day. Showers could bring local
ponding in roadways with poor drainage. Little change in this
pattern is anticipated through Tuesday. Wind flow will gradually
diminish at all levels below 30 kft through Monday and at lower
levels through Tuesday.

.LONG TERM...Wednesday through Sunday...

A mid to upper level ridge will continue over the central
Caribbean through the long term period. However, an upper level
trough is forecast to move over or just north of the region late
in the workweek. This will increase the potential for isolated
thunderstorm development over the interior and western sections of
Puerto Rio. At lower levels, a surface trough is expected to move
on Wednesday from the east. This will increase passing showers
across the USVI and across the southeastern/eastern sections of PR
by Wednesday morning, followed by afternoon showers across the
interior and southwestern sections of Puerto Rico. Later on the
week, an area of low pressure is forecast to develop over the
southwestern Atlantic and this could increase low level moisture
over the islands. An east to southeast wind flow is expected after
Thursday and afternoon convection should affect mainly the
interior and the west/northwestern sections of Puerto Rico.


&&

.AVIATION...SHRA in NE flow to continue area wide. Brief MVFR psbl
TJBQ, and in TJMZ aft 21/17Z. Otherwise all TAF sites expected to be
VFR. SHRA to increase over the interior of PR aft 21/14Z to bring
mtn obscurations. Wind ENE 5 to 15 kt with hir gusts nr SHRA. Max
winds blo FL540 NE btwn FL190-310 at 20-30 kt.


&&

.MARINE...A small pulse of a long period northerly swell will create
a high risk of rip currents along the northern beaches of Puerto
Rico and Culebra today. Seas will range overall between 3-5 feet
across the regional waters. However, small crafts should exercise
caution today across the offshore Atlantic waters due to seas up to
6 feet. Northeast winds will prevail between 10-15 knots. Showers
are expected over the southwestern waters of Puerto Rico this
afternoon.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 88 78 88 78 / 70 60 70 70
STT 89 78 88 78 / 50 30 40 40

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
458 AM AST Mon Oct 22 2018

.SYNOPSIS...Modest low level moisture and east northeasterly flow
will continue to bring minor showers across the forecast area and
onto windward slopes. Flow shifts to east southeast to southeast
by mid week and weakens to bring slightly warmer temperatures to
the north coast and continued shower activity as patches of
moisture move through.

&&

.SHORT TERM...Today through Wednesday...
A mid to upper level ridge will continue to promote dry air aloft
through the short term period. However, a weak surface trough just
east of the region will increase shower activity today. The best
moisture is forecast to remain across the Caribbean waters through
the evening hours. Under an east to northeast steering wind flow,
scattered to locally numerous showers are expected to move over the
local waters with some reaching portions of the U.S. Virgin Islands
and the eastern sections of Puerto Rico through the morning hours.
This slight increase in low level moisture today will aid in the
development of afternoon showers over sections of the interior and
southwestern PR, some with heavy showers that could lead to urban
and small stream flooding.

On Tuesday and Wednesday, winds are forecast to gradually diminish
and turn more from the east, with a more east to southeast flow by
Wednesday. Enough low level moisture will remain across the forecast
area, leading to passing showers with light rainfall amounts across
the U.S. Virgin Islands and the eastern sections of Puerto Rico
during the night and early morning hours...followed by diurnally
induced afternoon convection along the interior and western sections
of Puerto Rico.

.LONG TERM...Thursday through Monday...
Northwest flow at upper levels continues on Thursday while the
area remains south of a strong upper level jet of the same
direction. High pressure builds over the area over the weekend.
At mid levels high pressure continues over the area and weak
moisture is noted, but the driest air is still above 500 mb. At
lower levels a broad but weak trough is located over and north
northeast of the area on Thursday, but as a deep low off the
southeast coast of the United States strengthens, flow in the
local area turns southeast and the resulting flow is moderately
moist. This will keep showers in the forecast during the period,
but will also allow some warming on the north coast of Puerto
Rico. Since 1000-850 mb thicknesses remain nearly constant,
extreme values are not expected and some sea breezes may modify
the southeast flow expected during the period on the north coast.
Showers in interior and northwestern Puerto Rico are expected
each day and some will likely be heavy resulting in ponding or
very localized urban and small stream flooding. Surface flow
gains a northerly component on Sunday and shower activity will
move off the northwest coastal areas Sunday and Monday. Although
thunderstorms are not in the forecast since columnar moisture
values are generally in decline after Thursday, lifted indices and
divergence aloft do become more favorable, therefore
thunderstorms cannot be ruled out completely. Will look at later
model runs to determine if probabilities are strong enough to add
then Saturday through Monday.

&&

.AVIATION...Mainly VFR conditions are expected to prevail across all
the terminals through the forecast period. However, SHRA across the
regional waters may cause tempo MVFR cigs across the Leeward/USVI
terminals. Between 16z-22z SHRA expected to develop over SW PR,
impacting mainly the vcty of TJPS/TJMZ. East to northeast winds
expected btwn 10-15 kt.

&&

.MARINE...Diminishing winds over the next several days will lead
to lowering seas. Small craft advisories are not expected during
the next 7 days.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 87 78 88 78 / 60 40 40 50
STT 88 78 88 78 / 50 50 40 50