Caribbean - Central America Weather

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
438 PM AST Mon Apr 30 2018

.SYNOPSIS...Surface high pressure across the north central
Atlantic will prevail through midweek, then another surface high
pressure will enter the western Atlantic, keeping moderate
easterly winds for the next several days. A patch of moisture will
enter on Tuesday then drier air on Wednesday, but moisture will
increase significantly late on Thursday into the upcoming weekend,
just as an upper low starts approaching the local area.

&&

.SHORT TERM...This afternoon through Wednesday...

Afternoon showers developed across the northwestern quadrant of
Puerto Rico and these showers are expected to continue into the
early evening hours.After the shower activity subsides, isolated
and brief showers are expected tonight into early Tuesday across
the local waters, USVI and eastern PR. A patch of moisture is
expected on Tuesday, so the shower activity and coverage may
increase during the day, but the areas with the most significant
showers are still expected to be the northwestern quadrant of PR
in the afternoon hours due to local effects. Wednesday looks drier
as a dry slot moves in, causing below normal precipitable water
values. However, a isolated to scattered brief showers are still
expected across the USVI and eastern PR, then more significant
showers across western and northwestern PR in the afternoon due to
the diurnal heating and the below normal...but still enough
available moisture.

.LONG TERM...Thursday through Monday...

...From Previous Discussion...

An upper level low north of the area will dig southeast and
displace the ridge to the east Thursday and Friday. This will
send a jet from the southwest across the area, but the present GFS
is suggesting that considerable convergence aloft will work
against deep rising motion. Nevertheless, the passage of a low
level trough through the area Wednesday night will bring moisture
up from the southeast and with it rising motion in the lower
levels. This moisture and upward motion will arrive in several
bands that will almost assure that showers and a few
thunderstorms will develop over many areas Thursday through
Saturday. On Sunday most of the good convection will have moved to
the east, but residual moisture and heating will allow showers to
flare again. A minor surge of moisture on Monday will also bring
showers across Puerto Rico with isolated to scattered showers
around the U.S. Virgin Islands. This period beginning Thursday
will mark a major transition from the typically drier March and
April to May, the second wettest month of the year--at least for
eastern Puerto Rico. If moisture holds and upper levels become
even a little more favorable it may also mark the beginning of
regular local urban and small stream flooding in the heaviest
showers.


&&

.AVIATION...SHRA activity is still expected to develop across the
VCTY of TJMZ/TJBQ until 30/22z. These SHRA could produce brief
MVFR conditions. Rest of the terminals should see VFR conditions
through the forecast period. Brief passing SHRA may move across
the TJSJ and TIST terminals after 01/10z. Sfc winds will continue
from the ESE at 10 to 20 kts with occasional gusts and sea breeze
variations through 30/23z. Winds are expected to drop to 10 kt or
less across all PR and USVI terminals after 30/23z.


&&

.MARINE...Choppy seas up to 5 to 6 feet expected for the next
several days and winds up to 20 knots. Small craft should exercise
caution across some of the local waters. There will be a moderate
risk of rip currents across many of the local beaches for the next
several days.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 76 86 76 87 / 40 40 40 40
STT 77 85 77 87 / 50 40 40 40

[cycloneye]

Surface high pressure centered across the north central Atlantic
will maintain a light to moderate east to southeast trade wind
flow, as an induced surface trough will continue to develop and
lift northwards across the region through the end of the work
week. Increasing moisture advection by the end of the week along
with the arrival of an easterly wave will support a very moist
weather pattern as suggested by previous and recent model guidance.
Also the amplification of mid to upper trough and a deepening low
just west of the region will increase instability aloft and support
favorable dynamics for enhanced convective development over the
islands and coastal waters, with the wettest pattern so far expected
Friday through Saturday. Stay tuned!

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
509 AM AST Tue May 1 2018

.SYNOPSIS...High pressure at the surface will dominate the
Atlantic during the next week or so, bringing east then southeast
flow at lower levels. Moisture will increase today, diminish on
Wednesday and then ramp up through Friday evening to continue at
very high levels through the weekend. An upper level low will
form to the north and move southwest so as to bring strong
southwest flow over the area beginning late Thursday and
continuing through Sunday. This will bring a season of very
active weather Friday through Sunday. Once upper levels settle
down, moisture at lower levels will also wane and shower and
thunderstorms activity will diminish during the first half of next
week.

&&

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

Partly cloudy skies prevailed across Puerto Rico and the U.S. Virgin
Islands overnight. A patch of low level moisture extending from the
Caribbean waters, northwest through the U.S. Virgin Islands was
approaching the eastern half of Puerto Rico early this morning. A
line of showers associated with this feature affected Saint Thomas
and Saint John. Later, it moved to the eastern third of Puerto Rico.
Rainfall accumulation were less than half inch.

The aformentioned patch of low level moisture will continue to move
across the forecast area today. The inversion found just below 10
kft will disappear and allow better vertical motion. This will
result in an increase in cloudiness and showers for most of the
region. For this afternoon,the combination of this feature with
daytime heating and orographic effects will result in scattered
showers with isolated thunderstorms across the western interior
and northwest sections of Puerto Rico. The southeast wind flow
could induce the development of a streamer from El Yunque, which
could trigger some showers and possible isolated thunderstorms
across the San Juan metropolitan area this afternoon.

For tonight into Wednesday, a much drier air mass is expected to
encompass the region from the east. As a result, limit shower
activity is expected during the morning hours followed it by the
development of showers and thunderstorms across the west section of
Puerto Rico. For Thursday, a deepening upper level trough to our
west, and a moist southeast wind flow will result in a sharp
increase in moisture across the region.

.LONG TERM...Friday through Tuesday...
Conditions become much more unsettled Thursday and Friday as low
level moisture, a surface low forming in response to the upper
level trough, and a jet over the local area around that upper
level trough, all combine to bring deep moisture carried on
southeasterly flow and better instability. Currently it appears
that the best moisture and convection will form an arc that will
bring heavy rain north of our outer Atlantic waters and drag
through Puerto Rico later Friday and early Saturday. This is
likely to bring areas of urban and small stream flooding,
especially in higher terrain and north of the Cordillera. But,
the environment will be favorable for some showers each day--
mainly in the northwest portion of Puerto Rico. Moisture begins
tapering off rapidly on Tuesday.


&&

.AVIATION...Mainly VFR conditions will prevail across all TAF sites
through at least 01/16Z. Showers will continue to affect TIST
through the morning hours from time to time. Brief periods of MVFR
conditions can be expected. Brief periods of MVFR conditions are
expected across TJMZ and TJBQ from 01/18z-01.22Z. Low level winds
will continue mainly southeast at 10 to 15 kts.

&&

.MARINE...Marine conditions will be choppy with up to 6 foot seas
in the local Atlantic and Caribbean waters. Also local areas
around the coast of Puerto Rico will have winds of 18 to 20 knots
such that small craft will need to exercise caution. 7 foot seas,
signifying small craft advisory conditions, will begin Thursday
and Thursday night in both the Atlantic and Caribbean waters when
winds generated between the high pressure in the Atlantic and the
low west northwest of the area will further roughen seas. Small
craft advisories for the outer Atlantic waters will likely
continue into early next week.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 86 74 87 75 / 40 10 40 40
STT 84 77 87 77 / 50 10 40 70

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
502 PM AST Tue May 1 2018

.SYNOPSIS...
Surface high pressure across the Atlantic and a broad trough
across the central and eastern Caribbean will induce an east
southeast wind flow across the region through Wednesday. Winds are
to become more southerly by Thursday as the surface trough is
forecast to become amplified and lift northward across Hispaniola
based on the most recent model guidance. Low level moisture
transport will slightly diminish on Wednesday, but will quickly
rebound on Thursday and into the weekend, as the veering low level
winds will create a moist southerly flow across the region by
Friday and continue through the weekend. This pattern in combination
with a developing upper low near to or just west of the region
will support a very moist and unstable environment and increase
the potential for active weather conditions across the region
with good potential for areas of widespread rains and enhanced
thunderstorm activity through the weekend.

&&

.SHORT TERM...Rest of today through Thursday...
Showers and thunderstorms continued to form and steer northwest
across the central and northwest quadrant of Puerto Rico, as well
as downwind from El Yunque. Periods of moderate to heavy rains
affected the surrounding municipalities including parts of the San
Juan metro. Showers also formed and streamed westward across portions
of the U.S. Virgin Islands where periods moderate to local heavy rains
and brief gusty winds were experienced earlier in the day.

Expect shower activity over land areas to diminish around sunset
leaving partly cloudy to mostly clear skies overnight. Early morning
trade wind showers are however expected to affect the coastal waters
once again with some reaching parts of the east coastal sections of
the islands. On Wednesday, somewhat drier condtions and more sunshine
expected in most areas. However, local effects and daytime heating
will lead to afternoon showers and possible thunderstorms, mainly
over central and northwest PR and to a lesser degree around the
San juan metro area. Some isolated showers are forecast mainly on
the west end of the U.S Virgin islands but mostly sunny skies should
prevail.

A much wetter and unstable weather pattern is still forecast from
Thursday onwards and into the weekend, due to the amplification of
the upper trough west of the region and deep low level moisture
convergence. This will favor good potential for enhanced convection
with possibly widespread shower activity and increasing potential
for isolated but strong thunderstorms across portions of the islands.

.LONG TERM...Friday through Tuesday...
Conditions should become very unsettled by Friday and Saturday due to
the increasing moisture convergence, along with a surface low forming
in response to the developing upper level trough. This overall scenario
if it unfolds, will provide good ventilation and instability aloft as
a jet segment will round the base of the upper trough and lift across
the region. So far the wettest days still appear to be Friday through
Saturday with good potential for thunderstorms with heavy rains and
increasing chance for urban and small stream flooding across the
islands.

Moisture and showers development across the region should then
erode and gradually taper off by Monday and Tuesday of next week,
as the upper trough fills and lifts northwards and high pressure
ridging settles in once again across the region.

&&

.AVIATION...Showers are spreading across the islands. SHRA will
continue over or near TIST/TJSJ/TJBQ/TJMZ. TSRA could develop
downwind from El Yunque to affect the VCTY of TJSJ. A TEMPO was
included for TJBQ/TIST/TJSJ as some of this SHRA/TSRA could create
MVFR or even brief IFR conditions btwn 01/19-22z. Low level winds
will continue mainly southeast at 10 to 15 kts with higher gusts
especially in/near SHRA/TSRA, sea breezes are expected.

&&

.MARINE...Mariner should exercise caution across the Atlantic,
Caribbean and Local Passages due to seas up to 6 feet and east to
east- southeast winds between 10 to 20 knots. Protected waters
can expect seas below 5 feet overnight.

The risk of rip currents is moderate for the north, east and southeast
coasts of Puerto Rico. The U.S. Virgin Isles can expect a moderate
risk for most of St Croix beaches except for the west facing beaches.
Some beaches along St Thomas, Culebra and Vieques can expect a moderate
risk also.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 74 87 75 85 / 10 40 40 50
STT 77 87 77 84 / 20 40 70 70

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
451 AM AST Wed May 2 2018

.SYNOPSIS...Moisture will increase later today through Saturday.
Surface flow will turn from easterly today to southeast on
Thursday as a trough deepens west and northwest of the area.
Showers and thunderstorms will develop around the trough and flow
into it will carry moisture over the area through early next week.
Best moisture and rainfall is expected on Friday and Saturday,
but Sunday will also be wet. Some urban and small stream flooding
is expected where rains are heavy.

&&

.SHORT TERM...Today through Friday...
Partly cloudy to clear skies prevailed across Puerto Rico and the
U.S. Virgin Islands overnight. Latest satellite images depicted
fragmented areas of showers embedded in the trade winds. These
showers were affecting the eastern half of Puerto Rico. However, the
showers were short lived and were not leaving any significant
rainfall accumulation. For the rest of this morning into the
afternoon, a slot of dry air will move across the region. Limited
shower activity is expected to develop across most of the local
islands, except across the western interior and west sections of
Puerto Rico. By late tonight into Thursday, an increase in low
level moisture is expected as a upper level low develops north of
the Bahamas.

The aformentioned low will induce a moist southeast wind flow across
the region. This moist wind flow in combination with the deepening
low pressure system will result in a sharp increase in showers and
thunderstorms across the local region. For Friday, scattered to
numerous showers with thunderstorms are forecast to affect the
region as deep tropical moisture combined with favorable upper level
dynamics and orographic effects.

.LONG TERM...Saturday through Wednesday...
The upper level trough that is expected to dig toward Cuba
Thursday and Friday will enter Cuba Friday night. A jet will pass
over the Caribbean waters just south of the forecast area. Upper
level dynamics are still difficult to determine, but the GFS wants
to keep the most favorable divergence north of the Puerto Rico
with strong convergence spreading into the area from the
southeast. With moisture continuing to rise, however, expect
showers and thunderstorms to continue to develop Saturday and
Sunday. As showers and thunderstorms continue through the weekend,
the threat of urban and small stream flooding will continue to
develop and the threat of isolated mudslides will become more
likely. Models are not quite as wet as they were 24 hours ago, and
the best convection and rainfall amounts are expected to be north
and northwest of the island as a core of moisture wraps into the
low forming across Cuba and north into the Bahama Islands. Showers
will begin to taper off Saturday night and Sunday morning. A new
surge of moisture, however, will bring another round of showers
and some thunder storms overnight Sunday into Monday. Moisture
tapers off unsteadily into next week as the core of moisture
moving in from the southeast drifts west and the upper level low
almost disappears early next week as it moves back into the area
from the west. An upper level ridge returns with better weather in
the second half of next week. Temperatures will remain near or
slightly above normals.

&&

.AVIATION...VFR conditions will prevail across all TAF sites
through at least 02/16Z. Increasing cloudiness with showers are
expected across the western interior and west sections of Puerto
Rico during the afternoon hours. As a result, mountain obscurations
can be expected with periods of MVFR conditions possible across TJMZ
from 02/18z-02/22z. Low level winds will be mainly east at 15 to 20
kts.


&&

.MARINE...Winds from the southeast will generate 6 to 9 foot seas
over the tropical Atlantic that will spread into the area
beginning later on Thursday with up to 8 foot heights. Small craft
advisories are then likely to remain in the outer Atlantic waters
through Sunday.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 87 75 85 74 / 40 40 50 40
STT 87 75 84 76 / 40 70 70 40

[cycloneye]

From Weatherunderground.

Even if a tropical or subtropical system does not develop, there will be locally heavy rainfall in portions of Puerto Rico, the Dominican Republic, Haiti and eastern Cuba.

Widespread rainfall totals of greater than 3 inches are possible from Puerto Rico into eastern Cuba and Jamaica, with locally more than 5 inches expected. Heavy rainfall could lead to flash flooding and mudslides.



https://www.wunderground.com/news/2018- ... heavy-rain

[msbee]

Luis, I hope PR does not get too much heavy rain as I know people must still be living under tarps there, just like here.
Currently we are having moderately heavy rain showers here.

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
608 PM AST Wed May 2 2018

.SYNOPSIS...Upper level trough expected to amplify across the
southwestern Atlantic and over the northern Caribbean during the
second part of the week. An induced surface trough west of the
forecast area is expected to bring a moist east to southeasterly
wind flow through Saturday. Favorable upper levels should enhance
shower and thunderstorms development, especially on Friday and
Saturday. However, mid to upper level cloudiness could delay or
inhibit somewhat the onset of afternoon convection.


&&

.SHORT TERM...Tonight through Friday...
Showers over the western interior sections of PR should dissipate
by 23z. Then, partly cloudy skies are expected to prevail through
the overnight hours. Moisture is expected to gradually increase
from the east by Thursday morning with an east to southeast
steering wind flow. This will result in showers moving at times
across the USVI and the eastern sections of PR. By Thursday
afternoon, showers and thunderstorm development is expected
mainly to affect the interior and the north/northwestern sections
of PR. Streamers developing off the USVI and the eastern mountains
of PR could result in periods of moderate to heavy rainfall over
portions of eastern PR and the San Juan metro area.

Moisture over the area is then expected to increase rapidly from
Thursday through Friday. In addition, models are indicating good
divergence aloft across the regional waters, but mainly over the
Atlantic waters by Friday morning. This should sustain the
development of Thunderstorms over the local waters and then in the
afternoon provide dynamics for another round of showers and
thunderstorms, with heavy rainfall and flooding along the
mountain ranges and northern sections of PR. Also, under a moist
southeast wind flow, showers training across the southeastern
sections of PR and over the USVI could result in urban and small
stream flooding.

.LONG TERM...Saturday through Wednesday...(from prev discussion)
The upper level trough that is expected to dig toward Cuba
Thursday and Friday will enter Cuba Friday night. A jet will pass
over the Caribbean waters just south of the forecast area. Upper
level dynamics are still difficult to determine, but the GFS wants
to keep the most favorable divergence north of the Puerto Rico
with strong convergence spreading into the area from the
southeast. With moisture continuing to rise, however, expect
showers and thunderstorms to continue to develop Saturday and
Sunday. As showers and thunderstorms continue through the weekend,
the threat of urban and small stream flooding will continue to
develop and the threat of isolated mudslides will become more
likely. Models are not quite as wet as they were 24 hours ago, and
the best convection and rainfall amounts are expected to be north
and northwest of the island as a core of moisture wraps into the
low forming across Cuba and north into the Bahama Islands. Showers
will begin to taper off Saturday night and Sunday morning. A new
surge of moisture, however, will bring another round of showers
and some thunder storms overnight Sunday into Monday. Moisture
tapers off unsteadily into next week as the core of moisture
moving in from the southeast drifts west and the upper level low
almost disappears early next week as it moves back into the area
from the west. An upper level ridge returns with better weather in
the second half of next week. Temperatures will remain near or
slightly above normals.


&&

.AVIATION...SHRA across western Puerto Rico should dissipate by
23Z. Mainly VFR conditions are expected to prevail across all the
terminals through at least 12z. Showers are expected to increase
through Thursday across the USVI and PR termimals with mtn obscd
and SHRA/TSRA developing during the afternoon hours along the
interior and north/northwest PR. Surface winds will continue from
the east at 10-15 kt, bcmg east-southeast aft 03/10z and
increasing 15-20 kt with sea breeze variations aft 03/14z.

&&

.MARINE...Wind driven seas are expected to result in seas between
6-8 feet across the offshore waters and the Anegada Passage from
Thursday-Sunday. Small craft advisories will be in effect by then.
Elsewhere, seas are expected to range between 3-6 feet and winds
will continue from the east at 10-15 kts increasing up to 20 kts
on Thursday. A moderate risk of rip currents will continue through
Thursday across the northern, eastern and southern beaches of the
islands. A high risk of rip currents is expected on Friday across
the northern beaches of PR.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 75 85 74 85 / 50 60 40 60
STT 75 84 76 83 / 60 60 60 60

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
508 AM AST Thu May 3 2018

.SYNOPSIS....Upper level trough expected to amplify across the
southwestern Atlantic and over the northern Caribbean today
through the weekend. Favorable upper levels should enhance shower
and thunderstorms development, especially on Friday and Saturday.
However, mid to upper level cloudiness could delay or inhibit
somewhat the onset of afternoon convection.

&&

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

Moisture increases through the period reaching 1.87 inches of
precipitable water by Friday`s max heating. Layers currently dry
aloft will moisten considerably by Friday. Weak low pressure will
begin to from just north of the Windward Passage tonight and cause
surface flow to become more southeasterly through Saturday. Although
the north coast is expected to warm slightly today, the cloud cover
should offset much of the gain that is normally had with southeast
flow. High cirrus seen in the water vapor imagery is already marking
out the eastern side of an upper level trough digging into Cuba with
its low centered north of the Bahama Islands. As the upper low sinks
south over Cuba over the weekend, flow over the local area will
become more southwest. Upper level dynamics over us on the north
side of the jet south us will be most favorable on Friday. But,
since moisture continues to increase into Saturday, clouds and
showers will persist, but their intensity is uncertain owing to the
varying GFS solutions for divergence aloft. Thunderstorms associated
with the proximity of the upper level low will make urban and small
stream flooding possible today, but likely tomorrow and Saturday,
especially as rain falls in much the same places each day.

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

Strong high pressure system will build across the eastern
Atlantic through this period. As a result, relatively dry weather
conditions are expected to prevail across the region. Patches of
low level moisture embedded in the trade winds are expected to
affect the local islands from time to time. Overall, a seasonable
weather pattern is expected by the second week of May.

&&

.AVIATION...VFR conds are expected til 03/16Z. Aft 03/16Z SHRA/TSRA
will dvlp across PR--mainly north and over the Cordillera Central.
Areas of mtn obscurations and MVFR will dvlp across the area and
arnd TJMZ. Brief MVFR psbl other TAF sites including TNCM/TKPK.
Conds impvg aft 04/02Z except ern PR. Winds east 10 to 15 kt bcmg
aft 03/16Z ESE 10 to 20 kt with strong mdt sea breeze influences.
Max winds WSW 50-65 kt btwn FL430-480 thru 04/00Z.

&&

.MARINE...Across the coastal waters...seas between 5 to 7 feet are
expected to prevail across the forecast area through at least
Sunday. As a result, small craft advisories are in effect for most
waters except across the nearshore of western Puerto Rico were
seas between 2 to 4 feet are expected.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 86 75 85 74 / 60 60 70 70
STT 85 76 84 75 / 50 50 50 50

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
525 AM AST Sat May 5 2018

.SYNOPSIS...Moist southerly flow will promote the development of
showers and a few thunderstorms across the region the rest of the
weekend. Strong steering flow will move the showers and thunderstorms
fairly quickly across the local area...limiting the potential for
widespread flooding. Conditions will improve early next week as
mid-upper level ridge dominates the eastern Caribbean.

&&

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

A surface trough across SE-Cuba and the Bahamas is inducing a moist
southeasterly wind flow across the northeast Caribbean. Satellite
images indicated an area of clouds and moisture approaching the
islands from the east. This air mass will result in showers and
cloudy skies across the U.S. Virgin Islands, the southern and
eastern sections of Puerto Rico during the morning hours. As the
day progress, shower activity is expected to move into the
interior and northern slopes of Puerto Rico, where periods of
moderate to locally heavy showers and isolated thunderstorms can
be expected during the afternoon hours.

For Sunday...dry air intrusion at mid levels will limit the
coverage and intensity of shower activity, trade wind showers will
spread across the windward sections of Puerto Rico and the U.S.
Virgin Islands. Followed by afternoon activity to the north and
west of the Cordillera Central of Puerto Rico, and in the form of
streamers downwind from the USVI and smaller islands.

A typical weather pattern is expected on Monday. Easterly winds
will return with maximum temperature in the upper 80s or low 90s
across the coastal areas and in the low 80s across the mountain
areas.

.LONG TERM...Tuesday through Saturday

A drier and more stable pattern is expected next week as a
mid to upper level ridge will continue to build over the Northeast
Caribbean early in the week. Surface high pressure over the north
central Atlantic will hold through the end of the week...maintaining
moderate easterly winds across the local area most of the week.

No significant weather makers are anticipated for the upcoming
week as mid level ridge will dominate the weather conditions.
Stable conditions aloft will limit the vertical development of
showers each afternoon. Thunderstorms if develop will be short-
lived as mid-level moisture will be low. Light trade wind showers
will also occur at times, especially at night and early in the
morning.

&&

.AVIATION...Passing showers will continue across all terminal
except TJMZ where shower activity is not expected until the
afternoon hours. +SHRA with possible isol-TSRA are expected
in/near TJBQ/TJMZ btwn 05/18- 23z. MVRF conds could affect the
western terminals through that period. SHRA activity will remain
possible through the fcst period under a moist southeasterly wind
flow at 10 to 15 knots with higher gusts and sea breeze
variations.

&&

.MARINE...Fresh winds across the regional water will continue to
generate choppy seas through at least late monday night. Seas of
5-7 feet and winds of 15-20 kts are expected through early week.
A high rip current risk continues in effect for the north and east
facing beaches of Puerto Rico and the eastern beaches of St.
Croix through Sunday.

&&

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

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
549 PM AST Sat May 5 2018

.SYNOPSIS...Broad surface high across the Atlantic will hold
through next week, promoting moderate to locally fresh trades
across the region. Building upper level ridge will promote drier
air over the region. Fair weather conditions are expected through
much of next week.


&&

.SHORT TERM...Tonight through Monday...

High cirrus clouds across the Caribbean basin will continue to
stream over the islands through Sunday. Scattered showers and
possible isolated thunderstorms could affect mainly the open
waters west of the region during the overnight hours. Trade wind
showers on a brisk easterly wind flow due to a strong surface
high northeast of the region will move at times across portions of
the USVI and the eastern coastal sections of PR through the short
term period.

Diurnally induced afternoon showers are expected to form each day
downwind of the islands and from el Yunque area. However, they are
expected to move quickly leaving light rainfall amounts. However,
periods of moderate to heavy showers with a brief isolated
thunderstorms are expected mainly over portions of western PR and
the western waters of the island.

.LONG TERM...Tuesday through Saturday(from prev discussion)...

A drier and more stable pattern is expected next week as a
mid to upper level ridge will continue to build over the Northeast
Caribbean early in the week. Surface high pressure over the north
central Atlantic will hold through the end of the week...maintaining
moderate easterly winds across the local area most of the week.

No significant weather makers are anticipated for the upcoming
week as mid level ridge will dominate the weather conditions.
Stable conditions aloft will limit the vertical development of
showers each afternoon. Thunderstorms if develop will be short-
lived as mid-level moisture will be low. Light trade wind showers
will also occur at times, especially at night and early in the
morning.


&&

.AVIATION...Mainly VFR conds are expected across all the terminals
with VCSH possible through Sunday morning. ESE 15 to 20 knots
through 06/00z, becoming 10 to 15 knots overnight.


&&

.MARINE...Wind driven seas between 6-8 feet will keep hazardous
seas and small craft advisories in effect across the regional
waters, through the rest of the weekend and across the offshore
Atlantic waters through midweek. A high rip current risk continues
in effect through Sunday for the northwest to north central
beaches of PR and eastern St. Croix. East to southeast winds will
continue between 15-20 kts with higher gusts.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 75 87 76 88 / 40 50 40 40
STT 76 86 76 86 / 40 40 40 40

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
525 AM AST Sun May 6 2018

.SYNOPSIS...
Southeasterly flow will continue to favor moisture advection from
the Caribbean Waters. The high moisture content is inducing the
development of showers across the region today. A relatively dry
and more stable air mass will slowly fill in on Monday...limiting
the shower activity across the local islands.

&&

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

A surge of moisture enhanced by low level convergence has produced
scattered to numerous showers across the local waters overnight.
The Terminal Doppler detected a cluster of showers moving across
the northern U.S. Virgin Islands and a line of showers with
periods of moderate to heavy rainfall across northeast Puerto
Rico. High clouds have resulted in partly to mostly cloudy with
no shower activity across the rest of the island.

For today...low level convergence will enhance shower activity
across the U.S. Virgin Islands, eastern and northern Puerto Rico
during the morning. Periods of moderate to heavy rainfall can be
expected at times. Then, shower activity will develop along and to
the north of the Cordillera Central during the afternoon hours.
The southern half sections of Puerto Rico will observe mostly
sunny skies with warm temperatures and little or no shower
activity through the day.

Ridge builds aloft and moisture erodes across the islands the
first part of the week. Giving way to a typical weather pattern
with showers affecting the eastern half of Puerto Rico and the
U.S. Virgin Islands overnight and early in the morning, followed
by afternoon convection across west Puerto Rico are expected each
day. A more easterly wind flow and maximum temperature in the
upper 80s or low 90s across the coastal areas and in the low 80s
across the mountain areas will persist.

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

A stable and drying trend are anticipated the second part of the
next week as a mid to upper level ridge will continue to build
over the eastern Caribbean. This pattern is forecast to hold
through the end of the week. With the mid level ridge settling in,
thunderstorms are not likely but if develops will be short-lived
as mid-level moisture will be low.

Although...no significant weather makers are anticipated for the
this week...diurnal heating will combine with local effects to
produce a few rounds of scattered showers each afternoon across
portions of western Puerto Rico. Brief light showers over the
windward side of the islands are also possible at times as
moderate easterly trade winds will push patches of low level
moisture across the local region. However...no significant
rainfall accumulations are expected through the end of the week.

&&

.AVIATION...Passing showers will continue across all terminal
except TJMZ where shower activity is not expected until the
afternoon hours. +SHRA with possible isol-TSRA are expected
in/near TJBQ/TJMZ btwn 06/18- 23z. MVRF conds could affect the
western terminals through that period. E-ESE wind flow at 10 to 15
knots with higher gusts and sea breeze variations.

&&

.MARINE...Hazardous seas of 6-8 feet will continue across most of
the regional waters. Seas will subside across most of the waters
tonight, except across the offshore Atlantic waters where seas
will remain hazardous through midweek. East to southeast winds
will continue between 15-20 kts with higher gusts. High risk
of rip currents will continue through late tonight for north
central and northwest Puerto Rico as well as the east facing
beaches of St. Croix.

&&

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

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
538 AM AST Mon May 7 2018

.SYNOPSIS...
A surface high pressure off to the northeast of the islands will
continue to induce an east-southeast wind flow across the region.
Under this pattern moisture advection will produce trade wind
showers at times. Although dry air intrusion was detected at mid
levels, the available surface moisture and local effects could
result in limit afternoon convection across the western sections
of the islands.

&&

.SHORT TERM...Today through Wednesday...
Drier air has moved in and therefore only isolated showers are
expected in the morning across the USVI, Vieques, Culebra and
eastern PR, leaving minimal accumulations. However, the combination
of the limited moisture with the local effects and a weak upper
trough may cause showers to develop across the northern and eastern
sections of PR in the afternoon hours, with isolated thunderstorms
possible across the NW sections. Isolated showers are expected
elsewhere across the USVI and the local waters.

For Tuesday and Wednesday, the upper trough is expected to have
moved to the east, leaving an upper ridge of the local area. Also,
the available moisture is expected to be below normal, therefore the
shower activity is expected to be somewhat limited. The current
forecast has isolated brief showers in the morning and overnight
hours with scattered showers across portions of western and
northwestern Puerto Rico in the afternoon hours due to the
combination of the local effects causing a higher chance of rain
across those areas. The presence of an upper and mid level ridge
will likely inhibit the development of thunderstorms on Tuesday and
Wednesday afternoon.

.LONG TERM...Thursday through Monday...
Model guidance suggested a stable and dry air mass due to a
persistent ridge at mid to upper level over the eastern Caribbean.
Although this pattern will inhibit vertical development, shower
activity embedded in the trades will move across the windward
sections and local waters at times, especially during the early
morning and night time hours. In addition, as we move into May,
maximum temperatures are expected to reach the upper 80s and low
90s each day.

Each afternoon, the available moisture is forecast to interact
with local and diurnal effects resulting in shower activity along
and to the west of the Cordillera Central. However...no
significant rainfall accumulations are expected through the end of
the week.

&&

.AVIATION...
VFR conds are expected across the local terminals
through 07/16Z. SHRA and Isold TSRA development expected across the
NW sections of PR, which may affect TJBQ between 07/17Z and 07/21Z.
VCSH expected for TJSJ and VCTS possible at TJMZ after 07/16Z. East
winds at around 15kt with occasional gusts and sea breeze variations
expected.

&&

.MARINE...
Choppy seas due to an eat to southeasterly wind flow will continue
to result in seas between 5 and 7 feet with occasional seas up to
9 feet across the Atlantic Offshore waters. For that reason, a small
craft advisory continues in effect for the Atlantic Offshore
waters. Elsewhere small craft operators should exercise caution
due to seas up to 6 feet. Seas and winds are forecast to slowly
improve by the end of the work-week.

For the beach goers, the rip current risk is moderate across most
of the local beaches, except along the west coast of Puerto Rico
and most of the beaches of the northern U.S. Virgin Islands.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 87 76 87 77 / 30 20 20 40
STT 86 76 86 76 / 20 40 20 20

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
520 AM AST Tue May 8 2018

.SYNOPSIS...
A strong surface high pressure over the central Atlantic will
continue to promote an east southeast wind flow. A ridge at mid to
upper levels will induce a dry air mass at mid levels. However,
a moist trade wind pattern will bring passing showers at times
across the local waters, the U.S. Virgin Islands and the east and
north Puerto Rico. Afternoon convection is expected across the
western section of Puerto Rico.

&&

.Short Term...Today through Thursday...

A patch of moisture moved into the local area during the overnight
hours and it is expected to linger into the morning hours across the
USVI and eastern PR as well as the local waters. This patch of
moisture is expected to move west by the afternoon hours, which will
help in the development of showers across western PR when the
moisture combines with the diurnal heating and local effects. So far
this morning, the showers that have moved in have left up to a half
an inch of rain across portions of eastern PR and they are expected
to continue through the morning.

The upper trough that was over the local area yesterday has now
moved away and an upper ridge will take its place and persist for
several days. As the upper ridge builds and the available moisture
diminishes, the shower activity is expected to also diminish by
tonight and for Wednesday and Thursday. Having said that, the
typical weather pattern of showers affecting the eastern half of
Puerto Rico and the USVI in the nighttime hours and in the morning,
followed by afternoon showers across western Puerto Rico is still
expected, just that with the drier air in place, these showers are
expected to be limited and have less aereal coverage and duration.
Daytime maximum temperature are expected to be from the upper 80s to
low 90s across the lower elevations and in the upper 70s to low 80s
across the higher elevations.

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

A quit weather pattern is forecast to persist in the long term
due to a stable and dry air mass associated with a ridge aloft. A
trade wind pattern will push patches of moisture across the region
at times but the pattern aloft will inhibit vertical development
through much of the forecast period. This showers will affect the
windward sections and local waters each day, especially during the
early morning and night time hours. Model guidance continues to
suggest a trend to warmer maximum temperatures across the islands.

The available moisture is forecast to combined with local and
diurnal effects to result in afternoon convection each day. At
this moment, thunderstorm activity was not included until Tuesday,
when the potential seems to increase somewhat over western Puerto
Rico. No significant rainfall accumulation is expected through
this period.

&&

.AVIATION...
SHRA across the local area will cause VCSH across the
USVI terminals and TJSJ in the morning hours. After 08/16Z, SHRA
could affect the TJBQ and TJMZ terminals, which could cause brief
MVFR conds, VCSH expected for TJSJ with prevailing VFR expected
elsewhere. Winds will continue from the E to ESE at 10-15kt today
with occasional gusts. Winds to diminish after 08/23Z.

&&

.MARINE...
A small craft advisory is in place for the Atlantic Offshore
waters due to choppy seas between 5 and 7 feet with occasional
seas up to 9 feet. Elsewhere small craft operators should
exercise caution due to seas up to 6 feet and winds between 10 and
20 knots. Seas and winds are forecast to slowly improve by the
end of the work-week.

For the beach goers, the rip current risk is moderate across most
of the local beaches, except along the west coast of Puerto Rico
and most of the beaches of the northern U.S. Virgin Islands.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 87 75 88 76 / 30 40 20 20
STT 85 76 87 76 / 30 20 20 20

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
516 AM AST Wed May 9 2018

.SYNOPSIS...
A strong Bermuda high pressure continue to promote an east to
southeast wind flow which is bringing patches of low level
moisture with embedded showers at times. During the afternoon
hours, showers are expected to develop along and to the west of
the Cordillera Central as well as downwind from the U.S. Virgin
Islands.

&&

.Short Term...Today through Friday...

A very similar pattern to yesterday is expected today.
Among what is otherwise a relatively dry airmass, a
patch of moisture once again moved into the local area during the
overnight hours which could linger into the morning hours
across the USVI, eastern PR as well as the Caribbean waters. This
patch of moisture brought scattered showers to the USVI, and eastern
PR, leaving at least a half an inch of rain across southeastern PR,
but could leave up to an inch by the mid-morning hours. This patch
of moisture is expected to move west, which will help in the development
of showers across western and northwestern PR when the available
moisture combines with the diurnal heating and local effects.

An upper ridge will persist for the next several days, promoting a
more stable atmosphere. As this upper ridge builds and the available
moisture continues to diminish, the shower activity is expected to
remain mainly isolated to scattered today. Much drier air is expected
for Thursday, which will limit shower activity even more. However,
the same weather pattern observed in the past few days is expected for
the next few days. This means that showers are expected to briefly affect
the USVI and the eastern sections of Puerto Rico in the nighttime and
in the morning, followed by afternoon showers across western Puerto Rico.
But, with drier air over the area, these showers are expected to be
limited and have less aereal coverage and duration, especially on Thursday.
Another patch of moisture is expected on Friday, so the same shower pattern
is expected but with more overall rainfall coverage. Daytime maximum
temperature are expected to be generally in the mid to upper 80s
across the lower elevations and in the upper 70s to low 80s
across the higher elevations.


.LONG TERM...Saturday through Wednesday...

Model guidance continues to indicate a fair weather pattern
through the forecast cycle. But, shallow convection is expected
each day especially across the eastern half section of Puerto
Rico, the U.S. Virgin Islands and the local waters during the
nighttime and morning hours as patches of low level moisture
reaches the local region. The available moisture will then
combine with local effects and diurnal heating to result in
afternoon convection along and to the west of the Cordillera
Central.

Model guidance suggest that the dry air mass at mid levels will
diminish. In addition, the trade wind cap is suggested to relax
which could increase the possibility for thunderstorm development
after Tuesday of the upcoming week. However, confidence is low
given the fact of how far into the forecast period this is.

&&

.AVIATION...
SHRA will cause VCSH across the USVI terminals and TJSJ
in the morning hours. After 09/16Z, SHRA could affect the TJBQ
and TJMZ terminals, which could cause brief MVFR conds mainly for
TJBQ. VCSH expected for TJSJ with prevailing VFR expected elsewhere.
Winds will continue from the E to ESE at 10-15kt today with
occasional gusts. Winds to diminish after 09/23Z.

&&

.MARINE...
The small craft advisory continues in effect until this evening
across the Atlantic Offshore waters due to seas between 5 and 7
feet with occasional seas up to 9 feet. Elsewhere mariners should
exercise caution due to winds up to 20 knots and seas up to 6
feet. Marine conditions are expected to slowly improve after this
evening into the upcoming week.

Beach goers, the risk of rip currents continues moderate for most
of the local beaches, except for the northern U.S. Virgin Islands
and the western questions.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 88 76 88 75 / 30 20 30 40
STT 86 76 88 76 / 20 20 30 40

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
448 AM AST Thu May 10 2018

.SYNOPSIS...Strong surface high pressure will remain across the
central Atlantic for the rest of the workweek before it relocates
into the northeastern Atlantic, which will keep east to east
southeast winds for the next several days. Available moisture will
also be generally below normal but patches of moisture will be
moving through from time to time. Mid and upper levels expected to
remain fairly stable with mid to upper ridge over the local area
for the next several days. An upper low may develop to the
northeast of the local islands towards the end of the forecast
period, but the local islands may stay in the subsident side of
this upper low.

&&

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

A mid to upper level ridge over and to the northeast of the region
will continue to promote drier air across the forecast area. A broad
surface high pressure across the central Atlantic will continue to
promote moderate to locally fresh trades over the region. The
surface high will relocate over the Azores on Saturday, relaxing the
pressure gradient over the region. At the same time in the lower
levels a weak perturbation on the easterlies may slightly
increase moisture across the Caribbean and increase the overall
coverage of showers in the morning hours.

A minimum on PWAT content is expected Today, but light to moderate
showers should develop during the afternoon hours across the western
sections of puerto rico due to diurnal effects. Elsewhere, sunny to
partly cloudy skies are expected with brief iso showers downwind of
the USVI and over eastern PR. On Friday, moisture will increase
slightly with similar conditions as today. Another slight increase
in moisture on Saturday may lead to scattered showers over
the USVI, and eastern PR in the morning, then across western PR
in the afternoon.

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

Generally stable weather pattern with showers affecting the USVI
and eastern PR in the overnight and early morning hours as patches
of moisture move through amongst what is expected to be a drier
than normal airmass. The mid to upper ridge expected over the
local islands may keep a stable atmosphere over the local islands,
which should mostly inhibit deep convection. Although showers are
still possible and expected, the chance of thunderstorms will be
low if the ridge in the mid and upper levels prevail as forecast.
Afternoon showers across western PR and over portions of northern
and central PR are possible once the diurnal heating combines with
the local effects and available moisture. So even though there
doesn`t appear to be any synoptic scale feature that would aid in
the development of widespread showers and thunderstorms, and the
moisture is somewhat limited; showers are still expected to affect
portions of the local islands much like what we have been
observing the past few days.


&&

.AVIATION...Mainly VFR conditions expected to prevail across all
the terminals through the forecast period. A few passing showers
could move briefly over the Leeward terminals and create MVFR
CIGS. ISOLD to SCT SHRA expected to develop btw 16z-22z across
western PR impacting TJMZ with tempo MVFR conds. VCSH expected at
TJBQ/TJSJ. Surface winds will be from the east at 10-15 kt with
higher gusts and sea breeze variations aft 14z.


&&

.MARINE...Seas up to 6 feet are expected today across the local
waters and the coastal winds will be up to 20 knots. Small craft
operators are urged to exercise caution. Seas generally up to 5
feet can be expected through the weekend with moderate to locally
fresh winds up to 20 knots. There will be a moderate risk of rip
currents across most of the local beaches of Puerto Rico, Vieques
and Culebra, and Saint Croix for the next few days. The south
coast of Saint John has a moderate risk of rip currents today but
is expected be low for tonight into the upcoming weekend.



&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 88 75 87 76 / 30 40 40 20
STT 88 76 86 77 / 30 40 30 20

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
411 AM AST Fri May 11 2018

.SYNOPSIS...Strong surface high pressure still across the central
Atlantic will relocate just northeast of the Azores, which will
keep mostly moderate to fresh east to east southeast winds for
the next several days. Available moisture will also be generally
below or near normal but patches of higher moisture will be
moving through, which will have an impact on rainfall across the
area. Mid and upper levels are still expected to remain fairly
stable with mid to upper ridge over the local area for the next
several days. For the most part, persistence appears to be a good
forecasting method for the next several days with a few minor
changes depending on moisture content and wind speed and
direction. Otherwise the overall weather pattern is expected to
be fairly similar from day to day.

&&

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

As the surface high relocates over the Azores the trade winds
will weaken over the region. Low level moisture will increase
slightly over the region and showers are expected to last longer
than previous days. As a more east to southeast steering wind flow
is expected, shower activity will focus mainly over the northwest
quadrant of Puerto Rico and streamers developing downwind of El
Yunque could affect the San Juan metro area each afternoon.
Elsewhere, light rainfall amounts are expected due to showers
developing downwind of the islands and/or passing showers moving
at times through the short term period. A surge in moisture is
expected on Saturday, but mainly over the Caribbean waters. Due to
an east to southeasterly component on the winds, daytime highs
should range at or above normal values through the weekend.

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

Below or near normal moisture content with a ridge in
the mid and upper levels is still expected in the long term
forecast. However, latest model guidance has been somewhat
inconsistent with the long range forecast, as it is trending now
to an upper low to develop even further to the northeast that
previously forecast and bringing an area of higher moisture closer
to the local islands. Having said that, this change in upper low
positioning or slightly higher moisture does not cause a change
in the weather forecast. The lack of any mid to upper level
feature to cause instability will probably translate to having
only a slight chance of thunderstorm development. Having said
that, the moisture content will be enough to cause showers in the
night time hours and early mornings across the USVI, local waters
and north and eastern PR. Then in the afternoon, locally induced
showers are to be expected across portions of western PR, with a
slight chance of thunderstorms. Generally a similar pattern to
what we have observed the past few days.

&&

.AVIATION...Mainly VFR conditions expected to prevail across all the
terminals through the forecast period. However, passing SHRA could
move over the Leeward and USVI terminals through at least 14z. SHRA
expected to develop between 16z-22z over western PR, impacting
TJMZ/TJBQ with tempo MVFR conds. VCSH expected at TJSJ with brief
periods of -RA/RA during the afternoon hours. Winds will continue
east-southeast at 10-18 kt blo FL100, higher gusts and sea breeze
variations expected after 14z.


&&

.MARINE...Seas generally between 3-5 feet are expected today and
up to 6 feet for tonight and into the upcoming weekend with east
to east southeast winds between 10-20 knots. Moderate risk of rip
currents are expected across many of the local beaches today and
into the upcoming weekend.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 86 75 87 75 / 40 30 40 50
STT 87 76 86 76 / 30 40 40 50

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
428 AM AST Sat May 12 2018

.SYNOPSIS...Broad surface high will continue spread across the
central and northeastern Atlantic. Moderate to locally fresh
trades will prevail across the region. Diurnally induced
afternoon showers are expected each day, mainly over western
Puerto Rico.


&&

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

A surface ridge will slowly lift northwards allowing a weak low
level perturbation and associated moisture to cross the region today
through Sunday. The upper level ridge will slightly erode across the
region through Sunday as a short wave trough will move across the
western Atlantic just north of the region. Therefore, expect
sufficient trade wind moisture transport across the region during
the rest of the weekend to support early morning passing showers,
followed by diurnally and locally induced afternoon convection
across the coastal waters and local islands. The shower activity
should be focused mainly over portions of the east interior, central
and northwest sections of Puerto Rico. Afternoon showers should
however be of short duration with little vertical development as the
mid level ridge should hold in place and limit significant
development. For the remainder of the adjacent islands including the
U.S. Virgin Islands, only a few quick passing showers will remain
possible during the day as mostly fair weather and sunny skies is
forecast.

On Monday lesser shower activity and mostly fair weather skies is
again expected for the forecast area, as both the ridge aloft and
surface ridge will reestablish across the region and dominate the
local weather conditions. However, locally and diurnally induced
afternoon shower development cannot be ruled out. Shower activity if
any should be of short duration as the easterly trades should
slightly increase across the region by Monday.

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

Surface high northeast of the region will continue to bring
patches of low level moisture and trade wind showers across the
forecast area. A peak in moisture content if forecast by late
Monday night into early Tuesday morning. Mainly due to the
proximity of an upper trof to the west of the region. However,
dry mid levels will return quickly by Tuesday afternoon and are
expected to continue through at least Saturday. Overall, diurnally
induced afternoon moderate to brief heavy showers are expected to
develop each day over western Puerto Rico. Light to brief
moderate showers are expected to develop over the eastern
sections of PR through the long term period. Across the USVI and
nearby waters, trade wind showers will move at times, but mostly
fair weather conditions are expected to prevail.


&&

.AVIATION...VFR conds durg entire prd. SCT ocnl BKN cld lyrs en
route btw islands nr FL025...FL050...FL090 with -SHRA/SHRA til
12/14z. Brief MVFR with passing SHRA. Mtn top obscr ovr E PR in low
clds and -SHRA. SHRA development possible in and around TJMZ/TJBQ
12/16z-12/22Z. L/LVL wnd fm E 10-15 kts BLO FL200....BCMG fm N and
incr w/ht ABV. Sfc winds E-SE 5-10 KTS...BCMG 10-15 kts with ocnl
higher gusts aft 12/14z.


&&

.MARINE...Seas to continue up to 6 feet across the offshore
waters. Elsewhere, seas between 3-5 feet are expected. Winds will
continue from the east at 15-20 kt. A moderate risk of rip
currents will continue across the north, east and southern beaches
of the islands.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 87 76 87 77 / 40 30 30 20
STT 86 76 87 76 / 40 20 20 30

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
452 AM AST Sun May 13 2018

.SYNOPSIS...Mid to upper ridge will continue to build through
Tuesday. A broad TUTT is forecast to build northeast of the region
during the second part of the week. A surface high pressure will
relocate over the Central Atlantic, generating moderate to
locally fresh trade winds across the region through the end of the
week.


&&

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

During the rest of the morning...Passing low level clouds with
embedded trade wind showers will continue to affect the coastal
waters and the windward areas of the islands, bringing periods of
mostly light to moderate showers. This will be followed by a gradual
clearing, then locally and diurnally induced afternoon convection
mainly over parts of central and NW PR steered by the prevailing east
to southeast wind flow. While lesser shower activity is expected
today, isolated areas of moderate to locally heavy rainfall will
remain possible over northwest PR. Mostly isolated showers of short
duration can be expected elsewhere as an overall mixture of sunshine
and clouds is forecast for the rest of the day.

On Monday and Tuesday...Overall fair and stable weather pattern is
expected as the mid to upper level high pressure ridge will
reestablish aloft and hold through most of the period. Surface high
pressure ridge should again build north of the region to maintain
moderate easterly trade winds with a slight increase in the easterly
trade winds expected by Tuesday. Brief periods of passing early
morning showers can therefore be expected followed by the typical
locally and diurnally induced afternoon convection each day. the
activity should be focused mainly over parts of the interior and
west sections of Puerto Rico, and just downwind of the rest of the
local islands including the U.S. Virgin Islands. A better chance of
isolated afternoon thunderstorm is so far forecast by Tuesday due to
proximity of an upper trough expected to lift just northwest of the
region and this in turn might slightly erode the upper ridge.

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

Although dry mid levels will continue, sufficient low level
moisture will aid each day in the development of showers across
the western interior and western sections of Puerto Rico. Also,
streamers are expected to develop downwind of the islands and
showers developing from el Yunque area could affect San Juan and
vicinity. However, higher rainfall amounts are expected over
western PR. A tutt low is forecast to develop late in the period
just northeast of the region. A surge in passing showers and
moisture content is expected on Friday and Saturday.


&&

.AVIATION...VFR conds durg entire prd. BKN-OVC cld lyrs nr FL025...
FL040...FL090 with embedded passing -SHRA/SHRA across fcst area and
en route btw islands...bcmg SCT ocnl bkn aft 14/14z. Few TOPS nr
150. Sfc wnds fm E less than 10 kts bcmg ESE 10-15 kts aft 13/14z.
SHRA development likely in and around TJMZ/TJBQ fm 13/16z-13/22z.


&&

.MARINE...Seas will generally range between 3 to 5 feet and
occasionally up to 6 feet across the regional waters for the next
few days. East winds will continue between 15 to 20 knots. Choppy
seas up to 7 feet are expected during the second part of the week
across the offshore waters. A moderate risk of rip current
continues for most of the east, north and southern beaches of the
islands, with the exception in western PR and across the northern
USVI, where the risk is low.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 87 76 87 75 / 40 30 40 20
STT 86 77 87 74 / 20 30 30 50

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
406 PM AST Mon May 14 2018

.SYNOPSIS...Upper ridge is forecast to prevail through Tuesday. Short
wave trof is expected to briefly move from the west on Wednesday.
Tutt establish northeast of the region during the second part of the
week. At the surface, broad surface high will continue in place
through the long term period. A weak easterly perturbation is
forecast to move late in the weekend or by early next week, mainly
south of the region.


&&

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

The combination of the available moisture with local effect will
continue to produce afternoon showers across the northwest
quadrant of Puerto Rico. Rainfall accumulation will range between
half and three quarter of an inch. A few showers could develop
downwind from el Yunque into the San Juan metro area and across
the surrounding waters of the U.S. Virgin Islands through this
evening. Passing low level clouds and trade wind showers would be
possible overnight across the eastern half of PR and the U.S.
Virgin Islands.


A similar weather pattern is expected Tuesday and Wednesday.
Although no significant rainfall amounts are expected through the
forecast period, patches of low level moisture combined with low
level convergence will result in passing showers across the
windward sections of Puerto Rico and the U.S. Virgin Islands each
night and morning hours. Followed by locally induced showers each
afternoon over the west interior of PR Tuesday and Wednesday.

.LONG TERM...Thursday through Tuesday...

Tutt northeast of the region is forecast to remain in place through
the long term period. Guidance suggest that a weak easterly wave or
tutt induced perturbation, is forecast to move mainly south of the
islands across the Caribbean waters by Sunday or Monday. However,
the local area is expected to remain under the convergent side of
the tutt and this will inhibit the potential for widespread
convection over the islands. Meanwhile, at the surface a broad
surface high pressure will continue to bring patches of low level
clouds and passing showers through the long term period. Showers
should develop each afternoon due to the combination of the
available low level moisture, day time heating, sea breeze
convergence and orographic effect. Mainly over the western sections
of Puerto Rico and downwind of the smaller islands.



&&

.AVIATION...VFR conditions expected throughout the forecast period.
But, showers will develop across the NW-PR producing brief periods
of MVFR conds at JMZ/JBQ btwn 14/17-23z. Most of the activity will
dissipate by this evening with just a few VCSH at
TJSJ/TIST/TISX/TCNM/TKPK. Winds ESE at 10 to 20 knots with higher
gusts and sea breezes along coastal areas. Winds are expected to
drop around 10 kt aft 14/23z.


&&

.MARINE...Choppy marine conditions continue across the regional
waters with seas up to 6 feet across the open waters and below 4
feet in nearshore and protected waters. Seas will build to 6-8
feet the second part of the week as winds increase to around 20
knots by midweek.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 76 86 75 86 / 20 40 30 30
STT 75 87 76 86 / 50 50 30 30