Caribbean - Central America Weather

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
408 PM AST Sun Apr 30 2017

.SYNOPSIS...TUTT and associated area of low pressure and good
moisture pooling across the region will result in periods of
enhanced convection at least until Wednesday. The chance of urban
and small stream flooding each day with localized river flooding
will remain high. A gradual improvement in the overall weather
conditions is forecast during the latter part of the work week, as
the Tutt weakens and high pressure builds aloft limiting low
level moisture transport.

&&

.SHORT TERM...For the rest of the afternoon and evening, the very moist
and unstable environment will aid in the development of additional showers
and possible thunderstorms across the region. Shower activity over
land areas should however diminish by late evening, but is expected
to return along portions of the north and east coastal areas by early
morning. Soils are saturated and rivers and small creeks are swollen,
therefore any additional moderate to heavy rain will result in minor
flooding, sudden rises in river levels along with the possibility
of mudslides.

The upper level trough and associated area of low pressure is expected
to linger just north of the region and will continue to enhance showers
and thunderstorm development across the local area through Wednesday.
Low level moisture transport will remain high and as a result continued
cloudiness, with periods of showers with thunderstorms can be expected.
The best chance for thunderstorms and heavy rainfall should be focused
mainly across the eastern and northern half of Puerto Rico including
part of the San Juan metro area. Soils across Puerto Rico remain saturated
from present and recent rainfall. The potential for flooding of rivers
and streams as well as poor drainage areas will remain high. Mudslides
and debris flow will also remain likely in areas of steep terrain.
Local residents and visitors in Puerto Rico are urged to stay tuned
during the next few days.

.LONG TERM...As the TUTT weakens, a mid to upper level ridge will gradually
build across the forecast area. The ridge is then expected to hold through
at least the upcoming weekend. At lower levels, as the broad high pressure
across the central Atlantic lifts north and east of the region,the local
pressure gradient will weaken. Local winds are then expected to diminish
and become more east southeast by the end of the week. Although convection
will not be as widespread and frequent due to the building high pressure
ridge aloft and decreasing moisture transport, periods of showers and
isolated thunderstorms will remain possible across parts of the islands
and coastal waters through most of the upcoming week.

As the upper level ridge builds and low level moisture transport erodes,
a gradual improvement in the weather conditions is so far expected for
the latter part of the upcoming week, with slightly warmer temperatures
expected by Friday and into the following weekend.

&&

.AVIATION...SHRA/Isold TSRA across PR/USVI expected thru fcst
prd. Prds of SHRA/+SHRA may briefly reduce visibilities btwn 3SM-
5SM mainly at TJBQ/TJMZ/TJNR/TJSJ til 30/23z. BKN-OVC cld lyrs btw
FL020-FL100 durg prd. Isold TSRA psbl ovr ctrl mtn range of PR and
ovr coastal waters btw islands...N and S of PR. MVFR/psbl IFR conds
w/mtn top obscr psbl ovr west and ctrl and east PR til 30/23z. Low
level winds mainly E at 15-20 kts. Sfc wnds E-SE 10-15 kts w/ocnl
higher gusts mainly with SHRA...bcmg 10 kts or less aft 30/23z.

&&

.MARINE...Mariners should exercise caution due to seas between 4
and 6 feet and winds between 15 and 20 knots with higher gusts.
Isold thunderstorms will remain possible across the coastal waters
and local passages creating hazardous marine conditions. Stay tuned
for any additional special marine statement or product.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 75 84 75 85 / 50 50 20 50
STT 74 84 74 86 / 60 60 30 50

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
500 AM AST Mon May 1 2017

.SYNOPSIS...Moist and unstable conditions will prevail through
midweek under the influence of a mid-upper level trough.
Therefore...showers and thunderstorms with heavy rainfall could
result in flooding along small streams, urban and low lying areas.

&&

.SHORT TERM...Today through Wednesday...Mostly cloudy skies
prevailed across Puerto Rico and the U.S. Virgin Islands
overnight. An area of showers and thunderstorms affected the
eastern section of Puerto Rico. Rainfall accumulation from one to
two inches were estimated by the Doppler weather radar in some
localized areas mainly in El Yunque rainforest. Another area of
moderate to heavy rainfall moved inland affecting the southern
municipalities of Puerto Rico. For today, a very moist and
unstable environment,will aid in the development of showers and
thunderstorms across the Puerto Rico early in the afternoon, with
the activity expected to spread across the most of Puerto Rico
today. Heavy rainfall will lead to urban and small stream
flooding. Flash flooding cant be ruled out.

An upper level trough is expected to linger across the local region
enhancing the development of showers and thunderstorms across the
local area through at least Wednesday. Low level moisture is
expected to remain high through this period. As a result, periods of
showers with thunderstorms can be expected mainly each afternoon
across the Cordillera Central of Puerto Rico. Soils across Puerto
Rico are saturated from previous rainfall. Therefore, local and
visitors in Puerto Rico are urged to stay tuned during the next few
days as the risk for flooding continues high.


.LONG TERM...Thursday through Tuesday...Mid to upper level high
pressure ridge will build through the end of the week. At low
level...a weak high pressure will move eastward over the Tropical
Atlantic. Therefore...winds will remain from the southeast most
the second part of the week as the surface high pressure relocates
northeast of the islands. The overall moisture will decrease
through Sunday as mid-upper level promotes a subsidence air mass
across the local islands. Stability will increase limiting the
shower coverage and the intensity of the showers, especially
during the upcoming weekend.

&&

.AVIATION...Tempo MVFR conditions can be expected across TJPS
through at least 01/12Z. VCSH are expected across most TAF sites
through at least 01/16Z.Tempo MVFR and even IFR conditions with
mountain obscurations can be expected after 01/16Z in and around
TJSJ, TJMZ and TJBQ in SHRA/TSRA. Low level winds will be mainly
east at 10 to 15 kts.

&&

.MARINE...Marine conditions will deteriorate late tonight into Tuesday
as a NE swell combines with wind-driven seas. Seas of 4-6 feet are
forecast to build to 5-7 feet across the Atlantic Waters and Caribbean
Passages tonight. Seas will gradually subside by midweek as the
NE swell decays and winds return to normal.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 83 76 85 76 / 60 20 50 20
STT 82 77 84 77 / 70 30 50 50

&&

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
408 PM AST Mon May 1 2017

.SYNOPSIS...Surface high pressure north of the local islands will
shift eastward into the central Atlantic through Wednesday. This will
result in a fairly moist east to southeast trade winds across the forecast
area. Tutt and associated area of low pressure will linger north of
Hispaniola but will gradually fill and lift northwards through Wednesday
as a mid to upper ridge will build across the west Atlantic through
the end of the week.

&&

.SHORT TERM...Moist and unstable conditions are expected to continue
through Tuesday with gradual improvement by Wednesday and during
the latter part of the work week. Showers and isolated
thunderstorm development will therefore remain likely across the
coastal waters, portions of Puerto Rico and the surrounding waters
of the U.S. Virgin Islands during the rest of the evening and
overnight hours. However, activity over most of the inland areas
will again diminish by late evening leaving mostly cloudy skies
and a few light showers. By later tonight and early morning
showers and isolated thunderstorms are again expected to develop
across the regional waters, and affect mainly parts of the north
and east coastal sections of the islands particularly Puerto Rico.

Soil remain saturated and several rivers remain at high levels, therefore,
any additional rains during the next few days will quickly lead to quick
water rises and mudslides as well as urban and small stream flooding.

.LONG TERM...Thursday through Tuesday...Mid to upper level high pressure
ridge will build through the end of the work week and conditions should
become less favorable for significant convection. At low level...surface
high pressure ridge will shift eastward into the tropical Atlantic
to maintain a prevailing southeast wind flow across the northeastern
Caribbean. The overall low level moisture transport will gradually
decrease through the upcoming weekend as the building mid to upper
level ridge will promote subsidence and a more stable air mass across
the local region. Therefore expect shower activity to be more limited
to parts of the interior and west to northwest section of Puerto Rico.

&&

.AVIATION...SHRA across PR/USVI expected through the fcst prd. Some
SHRA/+SHRA could reduce visibilities btwn 3SM-5SM. As a result Tempo
were included to TJSJ/TJMZ/TJBQ/TISX. BKN-OVC ceiling will continue
at FL020-FL100 through at least 01/23z. TSRA, mountain obsc and +SHRA
are expected thru the fcst prd. Low level winds will continue mainly
from the E at 10-20 kts with higher gusts til 01/23z, dropping at
12 knots or less overnight.

&&

.MARINE...Mariners can expect seas to increase between 6 and 7 feet with
occasional seas of up to 9 feet overnight as a northeasterly swell arrives
across the local waters. Therefore a Small Craft Advisories will be
in effect for the Atlantic Waters and the Anegada Passage. Small craft
should exercise caution elsewhere.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 76 85 76 86 / 40 50 20 30
STT 77 84 77 84 / 40 50 50 50

&&

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
452 AM AST Tue May 2 2017

.SYNOPSIS...Surface high pressure north of the local islands will
shift eastward into the central Atlantic through Wednesday. This will
result in a fairly moist east to southeast trade winds across the forecast
area. Tutt and associated area of low pressure will linger north of
Hispaniola but will gradually fill and lift northwards through Wednesday
as a mid to upper ridge will build across the west Atlantic through
the end of the week.

&&

.SHORT TERM...Today through Thursday...Another round of showers and
thunderstorms are expected this afternoon over Puerto Rico,
particularly across the NW quadrant of the island. This is due to
the fact that there is still instability in the area and there
should be less cloudiness today, which would allow for some good
diurnal heating to combine with the available moisture and local
effects to develop showers and thunderstorms in the afternoon. The
latest guidance is suggesting that the Precipitable water values
for PR is over 2 inches, which is plenty of moisture. Eastern PR
is expected to observe quick showers in the morning with more
persistent showers in the afternoon under the easterly wind flow.

The above normal moisture is expected to persist until at least
Thursday, which will allow for some good shower and thunderstorm
activity in the afternoon hours for the next few days as this
moisture combines with the diurnal heating and local effects. Having
said that, the upper low that is causing instability over the local
area is expected to move east through the week, and therefore not as
much shower and thunderstorm activity is expected on Wednesday and
Thursday compared to today.

.LONG TERM...Friday through Wednesday...Mid to upper level high
pressure ridge will build through the end of the work week and
conditions should become less favorable for significant
convection. At low level...surface high pressure ridge will shift
eastward into the tropical Atlantic to maintain a prevailing
southeast wind flow across the northeastern Caribbean. The overall
low level moisture transport will gradually decrease through the
upcoming weekend as the building mid to upper level ridge will
promote subsidence and a more stable air mass across the local
region. Therefore expect shower activity to be more limited to
parts of the interior and west to northwest section of Puerto
Rico.By the early part of next week, a frontal boundary is
forecast to approach the region.

&&

.AVIATION...Brief -SHRA across the local area causing VCSH across
the local terminals except TJMZ. Easterly winds at around 15KT
starting after 02/13Z with sea breeze variations developing soon
thereafter. SHRA/TSRA expected over PR this afternoon will cause at
least some VCTS across TJMZ, TJBQ, and possibly TJSJ starting after
02/17Z. Winds to decrease slightly after 02/23Z but remain from the
east.

&&

.MARINE...Local Buoys indicated seas at around 7 feet in the
Atlantic offshore waters. Hazardous marine conditions will
continue to prevail through late tonight as a northwest swell
affect the local Atlantic waters and local passages. Small Craft
should exercise caution elsewhere.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 84 74 87 75 / 50 20 40 30
STT 85 74 85 76 / 50 40 40 30

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
334 PM AST Tue May 2 2017

.SYNOPSIS...Tutt and associated low continues to slowly fill and
lift northward as high pressure ridge builds across the region
from the west. Broad Atlantic ridge continues across the west
central atlantic and will maintain moderate easterly trade winds
across the region while transporting shallow low level moisture
true across the region.

&&

.SHORT TERM...As The upper trough lifts farther north during the next
24 hours, and the subtropical jet max moves east of the upper trough,
The region is expected to remain on the convergent/subsident side
of the trough. This scenario has already begun to limit convective
development across the region as conditions aloft becomes less favorable
for widespread convection. That said, expect more of an influence of
local and diurnal effects along with moisture availability to be the
driving force for morning and afternoon convection across the forecast
area at least through the end of the work week.

The low level ridge pattern will continue to dominate the over
all weather pattern, but still expect the local pressure gradient
to continue loosen as the ridge lifts slightly north and east of
the forecast area. However, expect the light to moderate east to
southeasterly wind flow to persist through Friday. For the remainder
of the week, a gradual decrease in cloud coverage and improvement
in the overall weather conditions is forecast, with periods Of
passing early morning showers followed by locally and diurnally
induced afternoon convection. The activity should then be focused
mainly across parts of the interior and west sections of Puerto
Rico. More streamer like afternoon convection will remain likely
over parts of the east sections of Puerto Rico as well as downwind
of the rest of the local islands.

.LONG TERM...By Friday through Tuesday of next week...Mid to upper
level high pressure ridge will build and linger across the region
supporting less favorable for significant convection across the region.
The surface high pressure ridge will also continue to shift farther
eastward into the tropical Atlantic to maintain a light to moderate
east southeast wind flow across the northeastern Caribbean. The overall
low level moisture transport will continue to erode by the end of the
week and through the upcoming weekend as the building mid-upper level
ridge will promote subsidence and a more stable air mass aloft. Therefore
expect shower activity with slight chance of isolated thunderstorm
activity which should be limited to parts of the interior and west
to northwest section of Puerto Rico. By the early part of next week,
a frontal boundary and associated prefrontal trough is forecast to
approach the region. This should again increase the chance for local
moisture convergence and upper level instability across the region.

&&

.AVIATION...SHRA across PR/USVI expected through the fcst prd.
SHRA/+SHRA/TSRA are expected to reduce visibilities btwn 3SM-5SM
mainly across TJBQ/TJMZ, and possibly across TIST/TJSJ/TISX. Mount
obsc is expected across mainland PR btwn 02/17-22z, with BKN-OVC
ceiling at FL020-FL100. SHRA are expected en route between the
Leeward islands and USVI/E-PR overnight. Sfc winds will continue
mainly from the E-ESE at 10-20 kts with higher gusts til 02/23z,
dropping at 12 knots or less overnight.

&&

.MARINE...Small craft advisory will continue in effect for the offshore
Atlantic Waters and Anegada passage through late tonight. Mariners can
expect gradually subsiding seas between 5 and 7 feet with occasional
seas up to 8 feet across these waters. Elsewhere, mariners should
exercise caution due to winds btwn 15-20 knots and seas at up to 6
feet.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 74 87 75 87 / 20 40 30 30
STT 74 85 76 85 / 40 40 30 30

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
455 AM AST Wed May 3 2017

.SYNOPSIS...Broad Atlantic ridge continues across the west
central atlantic and will maintain moderate easterly trade winds
across the region while transporting shallow low level moisture
across the region.

&&

.SHORT TERM...Today through Friday... Once again the high
resolution models are favoring convection across the western and
northwestern sections of PR this afternoon with only brief
scattered showers in the morning. This is because the overall
pattern really has not changed much. The surface high in the
Central Atlantic will remain in the area through the rest of the
workweek, keeping the local islands under an easterly wind flow.
However, the only significant difference might be that the upper
trough is moving to the east which will put us in the subsident
side of the trough with an upper ridge just to our east. Also, the
available moisture is not expected to change much in the next few
days, even though it has gone down from yesterday. The model
guidance suggests precipitable water values near 1.6 inches for
today and Thursday, increasing a bit on Friday, but overall a
fairly constant amount of moisture with an increase towards the
end of the week.

Because the upper level conditions are not particularly conducive
for prolonged thunderstorms, or even to support the development of
particularly strong storms, most of the thunderstorm development in
the afternoons for the next few days over PR will be due to the
combination of the available moisture with the local effects and
diurnal heating.

.LONG TERM...Saturday through Thursday...Surface high pressure
across the central Atlantic will dominate the local region through
Tuesday. From Tuesday through Thursday, troughiness will enhance the
development of shower and thunderstorm activity across the region.
GFS computer model forecast deep tropical moisture will encompass
the region at the end of next week.

&&

.AVIATION...Brief -SHRA across the local area causing VCSH across
the local terminals except TJMZ. Easterly winds at around 15KT
starting after 03/13Z with sea breeze variations developing soon
thereafter. SHRA/TSRA expected over PR this afternoon will cause at
least some VCTS across TJMZ, TJBQ after 03/17Z. Winds to decrease
slightly after 03/23Z but remain from the east.

&&

.MARINE...Seas up to 6 feet and winds up to 15 knots are expected
to prevail across the local waters. Small Craft should exercise
caution across most local waters. Seas will continue to improve
throughout the day.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 86 76 87 76 / 40 30 40 20
STT 85 76 85 76 / 40 30 30 20

&&

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
320 PM AST Wed May 3 2017

.SYNOPSIS...Weak mid level trough north of Puerto Rico/Hispaniola
drifting northward and weakening. Deep layer high/ridge over
western Atlantic drifting slowly eastward. long wave trough
approaching U.S. eastern seaboard from the west.


&&

.SHORT TERM...Tonight through Friday Night...Weak mid level trough
mentioned before will lift north and weaken lessening its effect
over the local area. Deep layer ridge will slowly drift east as a
long wave trough approaches the U.S. eastern seaboard from the
west. This will result in low level wind flow turning more ESE
through this period. Weather conditions across the islands will
depend mostly on diurnal heating and local breezes interactions.
That being said...will expect the usual afternoon convection
across interior and western portions of the big island of Puerto
Rico during the afternoons and mostly isolated night and early
morning showers over the U.S. Virgin Islands and eastern PR. Some
portions of the San Juan metro areas could see an isolated
afternoon thunderstorm as well.


.LONG TERM...Saturday through Thursday...Low level Atlantic ridge will
continue in control of the local weather conditions through
Sunday night. From Monday through Thursday, the long wave trough
mention before will induce troughiness enhancing the development
of showers and thunderstorms across the islands. Models indicate
abundant tropical moisture being advected over the region.


&&

.AVIATION...SHRA/TSRA expected to end around 22z across NW PR.
Mainly VFR expected to prevail through the overnight/early Thursday
morning across all PR/USVI terminals. At TNCM/TKPK a band of
moisture will continue through the evening hours, this can result in
tempo MVFR cigs and -SHRA at times. Low level winds will continue
ESE at 10-18 kts. However, light and variable winds at the
surface overnight due to the land breeze.


&&

.MARINE...Seas up to 5 feet...occasionally up to 6 feet, and
winds up to 15 knots should be expected across the local waters.
These conditions should prevail at least through the end of the
week.


&&

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

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
458 AM AST Thu May 4 2017

.SYNOPSIS...Weak mid level trough north of Puerto Rico/Hispaniola
drifting northward and weakening. Deep layer high/ridge over
western Atlantic drifting slowly eastward. Long wave trough
approaching U.S. eastern seaboard will approach local region from
the west by early next week.

&&

.SHORT TERM...Today through Friday...Not much has changed in the
overall pattern and persistence forecasting was the preferred
method. The overall moisture will remain fairly consistent with
Precipitable water values at around 1.6 - 1.8 inches for the next
few days. The upper levels will remain also fairly unremarkable
with westerly zonal flow for the next few days before an upper
ridge moves in on Saturday. This setup will cause for locally
induced showers and thunderstorms across PR once again in the
afternoons for the next few days. The USVI will observe mainly
fair weather with brief periods of rain as the tradewind showers
briefly affect the islands but mainly in the overnight hours and
in any streamers that may develop and affect the westernmost tips
of the USVI.

So for today through Saturday, showers and thunderstorms are
expected across the northwestern quadrant of PR in the afternoon and
also across portions of the Luquillo Mountain range and portions of
the San Juan metro. Today looks like the day with the most amounts
of rain with Friday and Saturday having slightly less significant
accumulations as the upper ridge approaches.

.LONG TERM...Saturday through Thursday...Long wave trough
approaching U.S. eastern seaboard will approach local region from
the west by early next week. This will increase the low level
moisture and local instability across the region. As a result, a
wet period could be expected across the local area as this trough
combine with local effects and diurnal heating.


&&

.AVIATION...Isold/Sct -SHRA expected across the local area through
04/14Z will cause VCSH across the local terminals except for TJMZ.
Afternoon SHRA/TSRA developing across PR will cause VCSH/VCTS at
TJBQ, TJMZ, and possibly TJSJ between 04/17Z and 04/23Z. TEMPO MVFR
conds possible at TJBQ between 04/18Z and 04/21Z. Winds will be
mainly from the east at about 10-15KT with sea breeze variations
developing after 04/14Z.


&&

.MARINE...Seas up to 5 feet...occasionally up to 6 feet, and
winds up to 15 knots should be expected across the local waters.
These conditions should prevail at least through the end of the
week.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 87 76 88 76 / 40 20 40 20
STT 85 76 86 77 / 30 20 20 20

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
500 AM AST Fri May 5 2017

.SYNOPSIS...Seasonable pattern expected today with near normal
moisture. Winds will remain from the east due to a surface high
pressure over the central Atlantic. Upper level high pressure is
present to the north of the local islands. Locally induced showers
and thunderstorms are expected today over Puerto Rico with
isolated to scattered brief showers elsewhere.


&&

.SHORT TERM...Today through Sunday...
Moderate amounts of trade wind moisture will continue today under
moderate east to southeast trade winds. However, recent model
guidance, upper air soundings, satellite imagery and local
analysis all suggest a gradual erosion of low level moisture/PWAT
over the next few days as the surface high lifts farther
northwards across the Atlantic by Sunday and mid to upper level
ridge builds overhead.

Therefore, expect mixed periods of clouds and sunshine each day becoming
mostly clear to partly cloudy during the late evening and early morning
hours. During the afternoons...available moisture along with ample
daytime heating and local effects will support afternoon convection
across parts of the interior and west sections of Puerto Rico with
streamer-like shower activity elsewhere, and mainly downwind of the
rest of the islands including the USVI. Isolated thunderstorms development
with brief periods of locally heavy rains will remain possible mainly
over the west sections of PR. Mostly fair weather skies with a slight
chance of brief passing showers is forecast for Vieques, Culebra and
the U.S. Virgin Islands each day. Daytime high temperature should be
in the high 80s along most coastal areas under the prevailing east
to southeast wind flow.

.LONG TERM...Monday though Saturday...
Overall moisture early next week will be near normal through
Wednesday but increasing thereafter and remaining above normal for
the second part of the upcoming week. Winds will also be from the
ESE early in the upcoming week at about 10-15 MPH but becoming
more easterly and rather light the second part of the week as a
COL develops between 2 SFC high pressure systems, one in the
central Atlantic and one over the northwestern Bahamas. This
lighter wind pattern until Friday. Some troughiness in the upper
levels could approach the local area on Tuesday which could
increase the local instability and increase the shower and
thunderstorm coverage. Other than that, not much looks like it
would be different to the usual pattern to be expected this time
of year with locally induced showers and thunderstorms over PR in
the afternoon hours with brief showers elsewhere in the forecast
area.


&&

.AVIATION...VFR thru 05/14Z across all PR/USVI terminals. FEW-SCT
cld lyrs nr FL020...FL050...few tops nr FL140 en route btw PR and
USVI and over near shore coastal waters. Offshore and ovr Caribbean
waters S of PR BKN-OVC nr FL080...FL100...FL250. At TNCM/TKPK til
05/14z...-SHRA/SHRA... with brief MVFR in SHRA and SCT-BKN lyrs nr
FL018...FL035. Low level winds will continue ESE at 10-15 kts. Sfc
wnd lgt/vrbl bcmg 10-15 kts with ocnl higher gusts aft 05/14z with
sea breeze variations.


&&

.MARINE...Small craft operators are urged to exercise caution as
seas will be up to 6 feet across the Atlantic waters. Seas of 5
feet or less expected elsewhere. The coastal winds will be
generally between 10 and 15 knots from the east. Also, there is a
moderate risk of rip currents across many of our local beaches.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 88 76 88 77 / 20 20 20 20
STT 85 76 86 77 / 20 20 20 20

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
312 PM AST Fri May 5 2017

.SYNOPSIS...A typical weather pattern for this time of the year
will continue across the northeast Caribbean for the next few
days. An upper level ridge is expected to build over the region
during the weekend. A surface high pressure over the central
Atlantic will maintain an east to east southeast wind flow across
the local islands. The combination of this feature will continue
to promote the development of locally induced showers and
thunderstorms over Puerto Rico during the afternoons with
isolated to scattered brief showers elsewhere.

&&

.SHORT TERM...Tonight through Sunday...
PWAT values will remain below 2.0 inches for the next several
days. An upper level ridge is expected to develop over the region
during the weekend. The upper ridge in combination with a surface
high pressure across the central Atlantic will continue to
produce clear to partly cloudy skies with only isolated shower
activity across eastern sections of Puerto Rico, Vieques, Culebra
and the U.S. Virgin Islands overnight and early in the mornings.
However, the expected abundant periods of sunshine will combine
with the limited available moisture and local effects to induced
the development of showers and thunderstorms across sectors of the
interior, western and northwest Puerto Rico with streamer- like
shower activity mainly downwind of the rest of the islands
including the USVI during the afternoon for the next few days.
Daytime high temperature should be in the high 80s along most
coastal areas under the prevailing east to southeast wind flow.

.LONG TERM...Monday though Saturday...
Not significant changes in the present weather pattern are
expected through at least mid week next week. A low pressure
system is expected to move across the northeastern U.S. seaboard
early in the week. An associated frontal boundary is expected to
approach the Greater Antilles from the west early in the week.
Moisture across Puerto Rico and the U.S. Virgin Islands will
increase due to the presence of the frontal boundary across Cuba
and Hispaniola by Tuesday. This feature will erode the upper level
ridge which could increase the local instability and increase the
shower and thunderstorm coverage across the local islands. Winds
are expected to remain from the east southeast until at least
Tuesday, inducing warmer than normal temperatures mostly along the
northern coastal municipalities of Puerto Rico. lighter wind
pattern is expected to encompass the region by midweek and
thereafter with a return the usual weather pattern for this time
of the year with locally induced showers and thunderstorms over PR
in the afternoon hours with brief showers elsewhere in the
forecast area.

&&

.AVIATION...VFR conds expected to prevail at the Leeward and USVI
terminals. Brief MVFR conds possible in and around JMZ,JBQ/JPS and
JSJ through 05/22z. ESE winds 10-15 knots with some sea breeze
variation becoming light and variable overnight.

&&

.MARINE...Small craft operators are urged to exercise caution as
seas will be up to 6 feet across the Atlantic waters. Seas of 5
feet or less expected elsewhere. The coastal winds will be
generally between 10 and 15 knots from the east. Also, there is a
moderate risk of rip currents across many of our local beaches.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 76 88 77 88 / 20 20 20 20
STT 76 86 77 86 / 20 20 20 20

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
508 AM AST Sat May 6 2017

.SYNOPSIS...Easterly winds will prevail through the early part of
next week before shifting slightly to the northeast as a surface
high develops to the northwest of the local area. Upper ridge to
prevail through Monday then an upper trough moves over the local
islands on Tuesday through Thursday with an upper jet being
forecast by the long range models. Locally induced showers and
thunderstorms expected this afternoon across the northwestern
quadrant of PR with near normal moisture expected.

&&

.SHORT TERM...Today through Monday...Ridge aloft will persist through
Sunday limiting shower development to the western interior of PR
and streamers forming off the USVI. Steering winds from the
southeast will focus rain activity over sections of NW PR and
streamer type light rain showers could develop from el Yunque area
into the metropolitan area this afternoon. Left isolated
thunderstorms on the forecast as there is a slight chance of short
lived thunderstorms each afternoon. Same pattern expected on Sunday.
Max temps should reach the high 80s and the low 90s across the
coastal areas of southern PR and other urban areas of the island,
across the rest of the islands max temps should range between the
mid to high 80s. Later on Monday the upper ridge weakens as deep
polar trof pattern across the Western Atlantic amplifies into the
local area. This will create favorable upper levels for thunderstorm
development across the Mona Passage and the Atlantic waters.

.LONG TERM...Tuesday through Sunday...
Available moisture is expected to increase quite a bit on Tuesday
into wednesday at the same time that an upper trough with
relatively strong winds, up to 75 knots according to the GFS
forecast soundings, is expected to move into the local area. This
setup, if it were to verify, will bring an increase in shower and
thunderstorm activity over the local area. There also appears to
be a weak moisture boundary to the north of the local area as a
surface high pressure develops to the northwest of the area,
bringing northeasterly winds to the local area.

Thereafter, we move into the subsident side of the upper trough
but still with relatively strong upper level winds. However, late
next week into next weekend we could expect typical convection for
the season which are showers and thunderstorms over PR in areas of
sea breeze convergence with isolated to scattered brief showers
elsewhere in PR and over the USVI.

&&

.AVIATION...Mainly VFR conditions expected to prevail across all
terminals during the next 24 hours. However, VCTS/tempo MVFR conds
possible at TJBQ between 06/18z-22z due to diurnally induced
SHRA/TSRA across the NW quadrant of PR. East to southeast winds at
12-18 kts with higher gusts after 14z due sea breeze variations.


&&

.MARINE...


&&

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

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
258 PM AST Sat May 6 2017

.SYNOPSIS...A seasonable weather pattern is expected to continue
across the region for the next few days. Upper level ridge will
remain over the region through early next week. A weak surface
high pressure over the central Atlantic will maintain an east to
east southeast wind flow across the northeast Caribbean through
early next week. The combination of these features will continue
to promote the development of locally induced showers and
thunderstorms over Puerto Rico during the afternoons with isolated
to scattered brief showers elsewhere.

&&

.SHORT TERM...Tonight through Monday...
PWAT values will continue below 2.0 inches as an upper level
ridge remain as the main weather feature over the region for the
rest of the weekend and early next week. This feature in
combination with a weak surface high pressure across the central
Atlantic will limit the showers and thunderstorms development
until at least Monday. Only isolated shower activity is expected
across eastern sections of Puerto Rico, Vieques, Culebra and the
U.S. Virgin Islands overnight and early in the mornings. However,
diurnal heating will combine with the limited available moisture
and local effects to induced the development of showers and
short lived thunderstorms across sectors of the interior, western
and northwest Puerto Rico each afternoon with shower activity
in streamers across south sections of the Metropolitan area.
Daytime high temperature should be in the high 80s mostly along
northern coastal areas under the prevailing east to southeast
low level wind flow.

.LONG TERM...Tuesday through Sunday...
A Low pressure center is expected to move over the Canadian
maritime provinces by Tuesday. An associated frontal trough will
move across Cuba and Hispaniola from the west late Monday and
Tuesday. A deep polar trof across the Western Atlantic and its
associated strong upper level winds is expected to amplify into
the northeast Caribbean Tuesday and Wednesday, as the upper level
ridge weakens rapidly. This will create favorable upper levels
dynamic for the development of shower and thunderstorm activity
across the region especially during the afternoon hours. A drier
air mass is expected to encompass the region from the northwest by
Friday as the upper trough shift eastward over the Lesser
Antilles. Thus, expect a typical weather pattern late in the week
and during the upcoming weekend with showers and thunderstorms
during the afternoons due to the combination of daytime heating
and local effects.

&&

.AVIATION...VFR conds expected to prevail at the Leeward and USVI
terminals as well as JPS/JSJ with VCSH possible. Brief MVFR conds
possible in and around JMZ AND JBQ through 06/22z in SHRA/TSRA. ESE
winds 10-15 knots with some sea breeze variation becoming light and
variable overnight.

&&

.MARINE...Relatively quiet marine conditions will prevail with seas
of 5 feet or less expected across most of the local waters. The
winds will be generally from the east between 10 and 15 knots.
There is a moderate risk of rip currents across many of our local
beaches.

&&

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

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
508 AM AST Sun May 7 2017

.SYNOPSIS...Surface high pressure across the central Atlantic will
gradually develop over the next few days, keeping the local winds
from the east to southeast through Tuesday. Upper ridge is
deteriorating and is expected to continue as an upper trough
approaches the local area on Tuesday. This will cause an increase
in the upper level winds and the overall instability which will
increase the shower and thunderstorm coverage over the local area
on Tuesday.


&&

.SHORT TERM...Today through Tuesday...
Fair weather prevailed during the overnight hours, only light and
brief passing showers were noted over portions of the U.S. Virgin
Islands and the eastern sections of Puerto Rico. Low temperatures
were from the mid 60s across the higher elevations to the mid 70s
across coastal areas. Mid to upper level ridge will continue to
limit shower activity across the forecast area. Expect sunny to
partly cloudy skies during the morning hours followed by diurnally
induced afternoon scattered showers and isolated thunderstorm
development across the western interior and northwestern sections of
PR. Above normal temperatures are expected once again across the
coastal and urban areas of the islands.

Upper ridge is expected to erode later on Monday as deep polar trof
and associated frontal system moves into the local area from the
Western Atlantic. As the ridge weakens, the areal coverage of
showers is expected to increase on Monday. As the frontal boundary
and the polar trof amplifies over the region...cloudiness will
increase as well as the frequency of showers with isolated
thunderstorms across the Mona Passage and the Atlantic waters,
specially on Tuesday. Urban and small stream flooding across
mainland Puerto Rico is expected on Tuesday afternoon.

.LONG TERM...Wednesday through Sunday...
By Wednesday, the deepest moisture should be already tot eh east
of the local islands but some lingering moisture could still be
present, with northeasterly winds which normally causes scattered
brief showers across the local waters, USVI, and northern and
eastern PR. Drier air is expected to be just to our north but this
drier air will likely stay to the north of the local area. Also,
we should start to be getting into the subsident side of the upper
trough that will be passing through the local area. For the second
part of the week we can expect typical convection over Puerto Rico
in the afternoon hours in areas of sea breeze convergence as well
as some possible showers that stream off the local islands and the
Luquillo Mountain Range. The available moisture will be near
normal from Wednesday until Saturday, then the moisture could
increase on Saturday and remain above normal on Sunday with winds
shifting to an east southeasterly direction.

Overall it looks like Tuesday might be the rainiest day this
week, thereafter we can expect brief showers in the morning and
overnight hours across the local waters, USVI and the eastern and
northern sections of PR then possible shower and thunderstorm
development in the afternoon in PR across portions of sea breeze
convergence.


&&

.AVIATION...VFR conditions expected to prevail across all terminals
during the next 24 hours. However, SHRA/TSRA can develop near the
vicinity of TJBQ/TJMZ between 07/18z-22z. East to southeast winds at
10-15 kts expected after 07/14z with higher gusts and sea breeze
variations.


&&

.MARINE...Seas are expected to be 5 feet or less for the next
several days with winds at 15 knots or less for the next few days
as well. There is a moderate risk of rip currents today across the
northern coast of PR and some beaches in Vieques, Culebra and
Saint Croix Islands.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 89 77 89 76 / 10 10 30 50
STT 88 77 85 75 / 20 10 40 60

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
307 PM AST Sun May 7 2017

.SYNOPSIS...
Upper level ridge is expected to deteriorate late Monday and
Tuesday as an upper trough approaches the local area. A weak
surface high pressure over the central Atlantic will maintain an
east to east southeast wind flow across the northeast Caribbean
through early next week. The available moisture is expected to
decrease for the second part of the week.

&&

.SHORT TERM...Tonight through Tuesday...
An upper level ridge will hold over the region through Monday.
This feature in combination with a weak surface high pressure
across the central Atlantic will continue to limit the showers
and thunderstorms development until at least Monday. However,
diurnal heating will combine with the available moisture and local
effects to induced the development of showers and short lived
thunderstorms across sectors of the interior, western and
northwest Puerto Rico Monday afternoon. Daytime high temperature
should be in the high 80s or lower 90s mostly along northern
coastal areas under the prevailing east to southeast low level
wind flow. Upper ridge is expected to erode rapidly late Monday as
a deep polar trof and associated frontal system approaches the
local area. Overall it looks like Tuesday might be the rainiest
day of the upcoming week. Therefore, cloudiness will increase as
well as the frequency of showers with isolated thunderstorms
across the Mona Passage and the Atlantic waters, especially on
Tuesday. Urban and small stream flooding and some river flooding
across mainland Puerto Rico is expected Tuesday afternoon.

.LONG TERM...Wednesday through Sunday...
As the upper trough axis remain over the northeast Caribbean,
abundant moisture will continue to induce the development of
shower and thunderstorm activity across the local islands and
surrounding waters through at least Wednesday. GFS guidance
suggests that the trough axis will shift to the east of the region
over the Lesser Antilles, Thursday and Friday. This will maintain
the region under the subsidence side of the upper trough,
decreasing the showers and thunderstorms coverage over the local
islands. The available moisture will be near normal from
late Wednesday until at least Friday with the return to the
typical weather pattern with showers and thunderstorms during the
afternoons due to the combination of daytime heating and local
effects across.

&&

.AVIATION...VFR conds expected to prevail at the Leeward and USVI
terminals. Brief MVFR conds possible in and around JMZ AND JBQ, and
possibly JSJ/JPS through 07/22z in SHRA/TSRA. ESE winds 10-15 knots
with some sea breeze variation becoming light and variable
overnight.

&&

.MARINE...Seas are expected to be 5 feet or less for the next
several days with winds at 15 knots or less for the next few days
as well. There is a moderate risk of rip currents for the
northern coast of PR and some beaches in Vieques, Culebra and
Saint Croix.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 77 89 76 87 / 10 30 50 50
STT 77 85 75 83 / 10 40 60 60

&&

[Gustywind]

Hi Cycloneye, glad to see you there!
I'm back lol.
I appreciate your daily posts in your tent, you're a maestro :
Regards
Gustywind

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
407 AM AST Mon May 8 2017

.SYNOPSIS...Upper level ridge is forecast to continue to
deteriorate from this afternoon and Tuesday as an upper trough
approaches the local area. A weak surface high pressure over the
central Atlantic will maintain an east to east southeast wind flow
across the northeast Caribbean through early next week.

&&

.SHORT TERM...Today through Wednesday...Variably cloudy skies
prevailed across Puerto Rico and the U.S. Virgin Islands this
morning. Passing showers were observed across the eastern half of
Puerto Rico with some affecting the U.S Virgin Islands as well.
Passing showers embedded in the trade winds are expected to continue
through the morning hours. Moisture is expected to increase today as
an approaching deep polar trough and associated frontal system
combined with daytime heating and local effects this afternoon.

For Tuesday and Wednesday, the aformentioned trough, with light
southeast to south wind flow at the surface will promote the
development of showers and thunderstorms across the region. Under
the southeast to south wind flow, better shower activity will be
expected north of the Cordillera Central and across the eastern half
of Puerto Rico.

.LONG TERM...The upper trough axis remain over the northeast
Caribbean, abundant low level moisture will keep favorable
conditions for the development of shower and thunderstorm activity
across the local islands and surrounding waters through at least Thursday.
Guidance suggests that the trough axis will shift to the east of
the region over the Lesser Antilles, late Thursday through
Friday.

The Subsidence area of the upper trough will move over the local
region. This will maintain the region under the stable side of
the upper trough, and therefore limiting the showers and
thunderstorms development over the local islands. The available
moisture will be near normal from late Wednesday until at least
Friday with the return to the typical weather pattern with showers
and thunderstorms during the afternoons due to the combination of
daytime heating and local effects across.


&&

.AVIATION...Passing showers are expected to affect TIST, TIST, and
TJSJ through at least 08/16Z. Periods of MVFR conditions with
mountain obscurations can be expected in the vicinity of TJSJ, TJMZ
and TJBQ from 08/16Z through at least 08/22Z in SHRA/TSRA. Low level
winds will be mainly southeast at 10 to 15 kts.


&&

.MARINE...Winds will slightly increase along the Atlantic near
shore waters up to 20 knots and seas will remain at around 6 feet
across the Atlantic offshore waters, therefore small craft should
exercise cautions across these waters. For the rest of the local
waters, seas are expected to be 5 feet or less for the next
several days with winds at 15 knots or less for the next few days
as well. There is a moderate risk of rip currents for the northern
coast of PR and some beaches in Vieques, Culebra and Saint Croix.



&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 88 75 87 75 / 40 30 50 50
STT 85 75 83 75 / 40 40 50 50

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
313 PM AST Mon May 8 2017

.SYNOPSIS...
Upper level ridge is expected to erode rapidly tonight and Tuesday
as an upper level trough with axis over Cuba and Hispaniola
continues to shift slowly eastward while amplify across the local
islands. A weakening surface high pressure over the central
Atlantic will maintain an east to east southeast wind flow across
the northeast Caribbean through mid week.

&&

.SHORT TERM...Tonight through Wednesday...
Variably cloudy skies is expected across the region tonight with
showers affecting mostly the eastern sections of Puerto Rico as
well as Vieques, Culebra and the U.S. Virgin Islands. An upper
level trough over Cuba and Hispaniola is expected to shift slowly
eastward while amplify over the local islands tonight and Tuesday.
This will erode the upper level ridge, resulting in an increase
in moisture transport across the region until at least mid week.
Overall it looks like Tuesday might be the rainiest day of the
week. As the upper trough approaches from the west, expect a
general increase in cloudiness as well as the frequency of showers
with isolated thunderstorms along and north of Cordillera
Central, Tuesday and Wednesday. Urban and small stream flooding
and some river flooding across mainland Puerto Rico is expected
both days. Daytime high temperature will continue in the high 80s
or lower 90s mostly along northern coastal areas under the
prevailing east southeast low level wind flow.

.LONG TERM...Thursday through Monday...
GFS guidance suggests that the trough axis will shift to the east
of the region over the Lesser Antilles, Thursday and Friday. This
will maintain the region under the subsidence side of the upper
trough, decreasing the showers and thunderstorms coverage over the
local islands. However, the lingering moisture will continue
above normal until at least Thursday. A return to the typical
weather pattern with showers and thunderstorms during the
afternoons and early evening hours due to the combination of
daytime heating and local effects across western and interior
sections of Puerto Rico is expected by Friday. An upper level
ridge is then expected to build over the northeast Caribbean
during the upcoming weekend through early next week.

&&

.AVIATION...VFR conds expected to prevail at the Leeward and USVI
terminals this afternoon and tonight. Brief MVFR conds possible in
and around JMZ AND JBQ, and possibly JSJ/JPS through 08/22z in
SHRA/TSRA. ESE winds 10-15 knots with some sea breeze variation
becoming light and variable overnight. Approaching trough will
result in VCSH/VCTS overnight and Tuesday with periods of MVFR
and mountain obscurations possible across PR and USVI terminals.

&&

.MARINE...Seas up to 6 feet and winds up to 20 knots are expected
across the local waters. There is a moderate risk of rip currents
for the northern coast of PR and some beaches in Vieques, Culebra
and Saint Croix.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 75 87 75 86 / 50 50 50 50
STT 75 83 75 85 / 60 50 50 50

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
507 AM AST Tue May 9 2017

.SYNOPSIS...
An amplifying trough is expected to produce unstable weather
conditions through at least Thursday. This mid-upper level trough
will meander over the islands and will interact with plenty of
surface moisture producing a wet pattern through most of the work
week. An upper level ridge is then forecast to build over the
northeast Caribbean by the upcoming weekend into early next week.

&&

.SHORT TERM...
Moisture continues to be drawn northeast along an old
frontal/shearline boundary and this moisture transport has been
aided by the recent passage of a tropical wave to the south. The
boundary is moving very slowly, but peak moisture of the week is
still expected this evening. Other indications are that instability
will also increase as upper atmosphere cools slightly. This should
produce more thunderstorms today than Monday. Also a broad upper
level trough will be moving into the area today and passing
tomorrow. Convection would be even stronger today were it not for
the relatively solid layer of clouds between 400 and 500 mb that
will block a large portion of the direct sunlight today. That
moisture will fade tomorrow and Thursday but shower activity will
not be reduced due better heating and persisting moisture in the
layers below. Thursday will also be the last day that upper levels
favor strong or enduring convection.

.LONG TERM...Friday through Tuesday...
Model guidance continues to suggest the upper level trough axis
over the Lesser Islands by Friday. If this weather pattern is
right, subsidence aloft will be unfavorable for deep convection
over the islands. A mid to upper level ridge is then forecast to
build aloft to bring a more stable weather conditions by Saturday
into Tuesday. However, the lingering surface moisture will result
in periods of showers and thunderstorms during the afternoons and
early evening hours due to the combination of daytime heating and
local effects mainly along the Cordillera and western sections of
Puerto Rico. The U.S. Virgin Islands, as well as the south and
east sections of PR, can expect passing showers mainly during the
overnight and early morning hours each day.

&&

.AVIATION...
Isold SHRA will continue across eastern PR and local waters to
the east through 09/14Z causing VCSH near TJSJ/TIST/TISX/TNCM/TKPK.
Aft 09/16Z afternoon SHRA/TSRA developing across PR will cause
mtn obscurations and VCSH/VCTS at TJBQ, TJMZ, and possibly TJSJ
between 09/17Z and 04/23Z. TEMPO MVFR conds possible at TJBQ/TJMZ
between 09/18Z and 04/21Z. Winds will be mainly from the ESE at
about 10-15KT with sea breeze variations developing after 04/14Z.
Max winds west 65 kts at FL410 at 09/18Z.

&&

.MARINE...
Mariners can expect seas up to 5 feet over the offshore waters and
less than 5 feet elsewhere. East to east-southeast winds at 10 to
15 knots will continue across the local waters, but gusty conditions
are likely in and near shower and thunderstorm activity. Thunderstorm
development is forecast to deteriorate the local marine conditions
as an upper level trough lingers across the region. Therefore,
mariners are urge to exercise caution under this weather pattern.

For the beach goers, there is a low to moderate risk of rip
current across the local beaches. In general, the moderate risk of
rip currents are for the beaches of St. Croix, Vieques, Culebra
and along the north, northwest and southeast coasts of PR.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 88 75 87 77 / 70 50 60 20
STT 84 75 84 75 / 60 70 60 30

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
333 PM AST Tue May 9 2017

.SYNOPSIS...An upper level ridge over the northeastern Caribbean
will continue to produce unstable weather conditions across the
region until at least Thursday. A surface high pressure over the
central Atlantic will maintain an east to east southeast wind flow
across the northeast Caribbean for the next few days. An upper
level ridge is forecast to build over the northeast Caribbean by
the upcoming weekend into early next week.

&&

.SHORT TERM...Tonight through Thursday...
An upper level trough will continue to maintain a wet weather
pattern across the region until at least Thursday. A weak tropical
wave to the east of the windward islands tonight is expected to
pass south of the region Wednesday and Thursday aiding in the
development of showers and thunderstorms across the region. Thus,
Variably to mostly cloudy skies are expected to continue across
the region tonight and Wednesday with showers and thunderstorms
across the local islands and surrounding waters. Most of the soils
along and to the north of Cordillera Central are expected to
become saturated, and the expected additional rainfall for the
next few days will produce Urban and Small Stream Flooding and
some rivers flooding. The upper trough axis is expected to shift
eastward over the Lesser Antilles late thursday resulting in an
improve in the weather conditions across the forecast area.

.LONG TERM...Friday through Tuesday...
Model guidance continues to suggest that the upper level trough
axis will shift eastward over the Lesser Antilles late Thursday
and Friday. As this happens, the subsidence side of the trough
will encompass the local islands, resulting in a decrease in
showers and thunderstorms over the local islands. A mid to upper
level ridge is then forecast to build over the region bringing a
more stable weather conditions by the upcoming weekend through
early next week. However, the lingering moisture will result in
periods of showers and thunderstorms during the afternoons and
early evening hours due to the combination of daytime heating and
local effects mainly along the Cordillera and western sections of
Puerto Rico. The U.S. Virgin Islands, as well as the south and
east sections of PR, can expect passing showers mainly during the
overnight and early morning hours each day.

&&

.AVIATION...VFR conditions expected to prevail at the Leeward
terminals tonight. Brief MVFR or even IFR conds possible in and
around TJMZ and TJBQ, and possibly TJSJ/TJPS through 08/23z in
SHRA/TSRA. Brief MVFR expected across the USVI taf sites tonight.
ESE winds 10-15 knots expected to become light and variable
overnight. Upper trough will continue to result in VCSH/VCTS
overnight and Wednesday with periods of MVFR and mountain
obscurations possible across PR and USVI terminals.

&&

.MARINE...Mariners can expect seas up to 5 feet over the offshore
waters and less than 5 feet elsewhere. East to east-southeast
winds at 10 to 15 knots will continue across the local waters, but
gusty conditions are likely in and near shower and thunderstorm
activity. Thunderstorm development is forecast to deteriorate the
local marine conditions as an upper level trough lingers across
the region. Therefore, mariners are urge to exercise caution under
this weather pattern. For the beach goers, there is a low to
moderate risk of rip current across northwest and southeast
local beaches of Puerto Rico and for the beaches of St. Croix,
Vieques and Culebra.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 75 87 77 87 / 50 60 20 20
STT 75 84 75 86 / 70 60 30 30

[cycloneye]

Area Forecast Discussion...UPDATED
National Weather Service San Juan PR
508 AM AST Wed May 10 2017

.SYNOPSIS...
An upper level trough meandering aloft will combine with abundant
low level moisture enhancing showers and thunderstorm activity
through at least late Thursday. A mid to upper level ridge is
expected to build over the region by Saturday into next week. At
the surface, troughs will move across the islands the next few
days. A surface high pressure over the central Atlantic will
maintain an east to east southeast wind flow across the northeast
Caribbean for the next few days.

&&

SHORT TERM...Today through Friday...

The broad band of moisture from an old frontal boundary has moved
into the Leeward islands and will stall there today. This has caused
mid and upper level clouds to clear--at least temporarily--and will
provide additional heating for the activation of shower and
thunderstorms around midday across much of western and interior
Puerto Rico. Southeast flow at the surface will cause showers to
again favor the northwest portion of the island. Although a short
wave has passed through the area and caused good convection,
thunderstorms and some flooding, we are still in the broad base of
the upper level trough that will continue to generate very favorable
conditions today and tomorrow. On Friday upper level support ends
and we are on the back edge of the moisture at mid levels, this will
limit the convection that will be favored by strong heating.

Although showers will continue through the period, the most intense
showers and thunderstorms are expected today and another round of
heavy rain may trigger some river flooding and areas of urban and
small stream flooding which will exasperate the situation of already
saturated and unstable soils to create mudslides. Therefore a flash
flood watch will be issued for the period from noon today to 6 PM
AST today.

.LONG TERM...Saturday trough Wednesday...
A ridge aloft is expected to build over the region by the upcoming
weekend into next week. However, model guidance quickly bring a
tropical wave with abundant tropical moisture across the region
Sunday or Monday. This scenario can increase the potential for
showers and thunderstorms across the islands. Moisture is forecast
to rapidly decrease Tuesday into mid week. The lingering moisture
will result in periods of showers and thunderstorms during the
afternoons and early evening hours due to the combination of
daytime heating and local effects mainly along the Cordillera and
western sections of Puerto Rico. The U.S. Virgin Islands, as well
as the windward sections of PR, can expect passing showers mainly
during the overnight and early morning hours each day.

&&

.AVIATION...
Isold SHRA will continue across eastern PR and
local waters to the north through 10/14Z. Aft 09/16Z afternoon
SHRA/TSRA developing across PR, but mainly wrn and interior, will
cause mtn obscurations and VCSH/VCTS at TJBQ, TJMZ, TJPS, and
possibly TJSJ between 09/17Z and 04/23Z. TEMPO MVFR conds possible
at TJBQ/TJMZ between 09/18Z and 04/21Z. Winds will be mainly from
the ESE at 5-15KT with sea breezes developing after 04/14Z. Max
winds west 50-70 kts at FL410-470 incrg thru 11/12z.

&&

.MARINE...
Mariners can expect seas between 2 and 5 feet across the region,
but are urged to exercise caution across the Anegada Passage and
the U.S. Virgin Islands surrounding waters due to winds between
15 to 20 knots. Elsewhere expect east to east southeast winds
between 10 and 15 knots. Seas expected to continue at less than 5
feet for the next several days. A trof pattern will enhance
showers and thunderstorms formation across the coastal waters.
Therefore, mariners and beach goers should be alert and monitor
the local marine products as weather conditions can deteriorate
quickly over the waters and coastal areas.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 86 76 86 76 / 50 30 30 20
STT 84 76 85 75 / 50 40 40 30

&&