Caribbean - Central America Weather

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
309 PM AST Thu Mar 9 2017

.SYNOPSIS...A strong surface high pressure over the central
Atlantic, northeast of the region, will continue to provide a
vigorous easterly wind flow across the local islands for the next
couple of days. This wind continues to bring patches of
cloudiness and showers across the local islands today into early
Friday morning. A mid to upper level ridge is expected to develop
over the region during the upcoming weekend, maintaining an stable
weather pattern across the region. Hazardous marine conditions as
well as dangerous surf conditions will continue to prevail
tonight.

&&

.SHORT TERM...This evening through Saturday...The surface high
pressure across the central Atlantic will continue to produce an
easterly wind flow across the forecast area for the next several
days. This feature is expected to produce winds at 15-20 MPH with
higher gusts tonight and Friday. These winds will continue to
transport areas of cloudiness and showers mostly across eastern
sections of Puerto Rico overnight and early Friday morning. This
moisture in combination with daytime heating and local effects
will induce the development of showers across western an interior
sections of Puerto Rico each afternoon. A mid to upper ridge is
expected to develop over the region late Saturday and Sunday.

.LONG TERM...Sunday through Friday... A mid to upper level ridge
is expected to build across the local islands late in the weekend.
These feature will erode the moisture advection over the region by
early next week, inducing a generally dry and stable weather
pattern across the forecast area for most part of the upcoming
work week.

generally dry weather pattern Mon with low level moisture eroding
across the eastern Caribbean. The ridge pattern aloft is then
expected to flatten by the end of the upcoming work week as a mid
to upper level trough and associated surface front moves across
the central Atlantic. Winds are expected to shift east southeast
early next week as a surface low develops across the western
Atlantic. The GFS model guidance suggests an increase in low
level moisture by next weekend under the expected east southeast
wind flow.

&&

.AVIATION...Mostly VFR conditions expected tonight across most of
the local flying area. VCSH are expected across the Leeward, USVI
and eastern PR taf sites overnight and until 10/14Z. Winds
continue mostly from the E at around 10-15KT with higher gusts,
increasing to 15-20KT after 10/14Z.

&&

.MARINE...Although the northerly swell will continue to slowly subside
tonight...fresh easterly winds will continue to create rough and
hazardous seas across the regional waters through the end of the
week. The local buoy network is indicating seas between 7 and 8
feet with breaking waves around 10 feet. As a result a High Surf
Advisory continue in effect.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 72 83 73 84 / 60 60 20 20
STT 73 83 72 83 / 40 40 20 20

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
431 AM AST Fri Mar 10 2017

.SYNOPSIS...SFC high pressure across the central Atlantic will
continue to move east, relaxing the local pressure gradient in the
process and therefore causing the easterly winds to gradually
diminish. A broad high pressure in the mid to upper levels is
expected to develop over the local area, maintaining stable
conditions for the next few days.

&&

.SHORT TERM...Friday through Sunday...

Variably cloudy skies prevailed across PR and the USVI overnight.
Isolated to scattered showers were observed across the USVI as
well as eastern PR with numerous showers noted over the Caribbean
waters. Shower activity will continue across the forecast area,
particularly the Caribbean waters through at least early this
morning. Although a drier air mass will move in by mid morning,
still expect a few passing showers across windward areas followed
by locally induced showers across northwest PR in the afternoon.

Moisture advection will continue at times through Sunday as an
induced surface trough prevails west of the forecast area. This
feature will result in east southeast winds, enhancing the
aforementioned moisture transport. Therefore continue to expect a
similar weather pattern with passing showers across windward areas
and some locally induced afternoon showers across west Puerto Rico
Sat-Sun.

.LONG TERM...The broad trough in the upper levels is expected to
maintain stable weather conditions for the early part of next
week. The long range models are indicating a seasonable weather
pattern with relatively small amounts of rain with normal moisture
which to be expected for this time of year. Nighttime and early
morning brief showers across the local waters, eastern PR, and the
USVI are possible with this expected setup, and then in the
afternoon hours, some showers may develop across western PR,
especially in areas where there is Sea Breeze convergence, but the
amounts of rain at this time appear to be modest.


&&

.AVIATION...Mostly VFR conds are expected through the forecast
period with passing showers in and around the Leeward and USVI
terminals as well as JSJ through the morning hours. Brief MVFR conds
are possible after 10/16z at JBQ in locally induced SHRA.
Easterly winds 10-15 knots are expected today with some sea breeze
variations.


&&

.MARINE...Marine conditions will remain hazardous for the next few
days, at least. There is also a moderate or high risk of rip
currents across most of the local beaches today. At this time
there is still a small craft advisory for most of the local waters
due to seas of up to 10 feet. The local nearshore buoys are
reporting diminishing seas, most of them reporting seas of 5-6
feet, but the latest guidance...which is currently under
estimating the wave heights...is still suggesting of hazardous
seas today over the local waters. For that reason, we kept the
small craft advisory for today and Saturday but then made some
adjustments starting late Saturday and into the weekend. Mariners
can expect winds of 15-20 knots and seas up to 10 feet across the
Atlantic offshore waters.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 84 74 85 74 / 20 20 30 20
STT 83 74 83 73 / 20 30 30 50

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
241 PM AST Fri Mar 10 2017

.SYNOPSIS...A strong surface high pressure over the central
Atlantic, northeast of the region, will continue to provide a
vigorous easterly wind flow across the local islands until at
least Saturday. This wind flow will continue to transport patches
of cloudiness and showers across the local islands. The surface
high is expected to moves further eastward, gradually diminishing
the wind speed across the region by the weekend. A mid to upper
level ridge is expected to build over the region during the
weekend, maintaining an stable weather pattern across the region.

&&

.SHORT TERM...This evening through Sunday...The surface high
pressure across the central Atlantic will continue to produce an
easterly wind flow across the forecast area for the next few
days. These winds will continue to transport areas of cloudiness
and showers mostly across eastern sections of Puerto Rico
overnight and early Saturday morning, followed by afternoon
convection across interior and western sections of Puerto Rico due
to the combination of daytime heating and local effects. A mid to
upper ridge is expected to develop over the region during the
weekend.


.LONG TERM...Monday through Saturday...A mid to upper level ridge
is expected to build across the local islands through early next
week. This feature will erode the moisture advection over the
local islands, inducing a generally dry and stable weather
pattern across the forecast area for most part of the upcoming
work week. The ridge pattern aloft is then expected to flatten by
the end of the upcoming work week as a mid to upper level trough
and associated surface front moves across the central Atlantic.
Winds are expected to shift east southeast early next week as a
surface low develops across the western Atlantic. The GFS model
guidance suggests an increase in low level moisture by next
weekend.

&&

.AVIATION...Mostly VFR conditions expected tonight across most of
the local flying area. VCSH are possible across the Leeward, USVI
and eastern PR taf sites overnight and until 11/14Z. Winds
continue mostly from the E at around 10-15KT with higher gusts.

&&

.MARINE...Although the northerly swell will continue to slowly subside
tonight...fresh easterly winds will continue to create rough and
hazardous seas across the regional waters through the end of the
week. The local buoy network is indicating seas between 7 and 8
feet with breaking waves around 10 feet. As a result a High Surf
Advisory continue in effect.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 74 85 74 84 / 20 30 20 20
STT 74 83 73 84 / 30 30 50 50

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
453 AM AST Sat Mar 11 2017

.SYNOPSIS...Surface high pressure across the eastern Atlantic will
continue to drift to the NE into the NE Atlantic for the next few
days. Because of that, the local pressure gradient will continue
to relax and cause moderate winds over the islands. A patch of
slightly drier than normal moisture is expected to move in across
eastern PR this morning and early afternoon while the western and
northwestern quadrant of PR has slightly higher than normal
moisture for the afternoon. Near normal moisture elsewhere. Ridge
aloft should keep a stable atmosphere locally, which will cause
the shower development to be induced due to the combination of
the local effects, diurnal heating and available moisture.

&&

.SHORT TERM...Saturday through Sunday...
In general, very limited shower activity was detected across the
islands overnight. Some light brief showers affected the windward
sections of Puerto Rico and the Northern U.S. Virgin Islands.
Most of the cloudiness dissipated around Midnight leaving mostly
clear to partly cloudy skies across the region. The minimum
temperatures along the coastal areas were between the mid and low
70s and around the low 60s across the mountainous areas.

A dry air mass is expected to move over the region during the
morning hours. This will limit showers across the islands, but a few
of them are possible across E-PR/USVI. At this time, no shower
activity is expected across the Southern Plains, and relative
humidity values are expected to decrease near or below 50%.
Therefore expect mostly clear skies with little or no shower
activity across PR and the USVI this morning. A moisture advection
is expected to increase showers over the region by late this morning
into the afternoon hours. The best chances of showers are for
interior and western sections of Puerto Rico. However, shower
formation is also possible downwind from the U.S. Virgin Islands,
Vieques and Culebra. These showers could affect the eastern sections
of PR, as well as the San Juan Metro Area.

Under a ridge pattern aloft, the regional weather pattern will be
driven by low level moisture advection. As a result, trade wind
showers will continue at times across the windward areas Sunday and
Monday. In addition, locally induced afternoon showers across west
Puerto Rico are also expected each day.

.LONG TERM...Monday through Sunday... Moderate easterly winds are
expected to prevail in the long term with near normal moisture.
Also, the usual pattern for this time of year of brief showers in
the overnight and early morning hours and then some diurnally
induced showers in the afternoon across western PR can be expected
for most of this week except for Thursday. A patch of higher
moisture moves into the local area on Thursday, which will cause
an increase in the shower activity in the brief showers overnight
Wednesday into Thursday and then probably more numerous showers
induced on Thursday afternoon once the moisture combines with the
local effects and diurnal heating. However, from Friday and
through next weekend, everything seems to fall back to the near
normal moisture with overnight and morning brief showers. There is
a frontal boundary that may approach the local islands on
Thursday into Friday but it appears to stay just to our north and
if it approaches even more it may actually be very weak to cause a
frontal passage. Having said that, it is far into the forecast
period so there is considerable uncertainty.

&&

.AVIATION...In general VFR conds are expected this morning through
the morning hours. However, mountain obsc SHRA/+SHRA are expected
across the interior and Western Sections of PR btwn 11/17-23z.
Therefore BKN-OVC ceilings at FL020-FL090 are possible as well as
periods of SHRA/+SHRA at times at TJMZ/TJBQ, elsewhere just passing
-SHRA/SHRA. Calm to light and variable winds til 11/12z, increasing
at 10 to 16 kt from the E-SE and with sea breeze variations.


&&

.MARINE...Seas continue to be hazardous across the offshore
Atlantic waters. Latest buoy observations are suggesting that seas
are now under 7 feet across the nearshore waters and are
diminishing; the local guidance suggests that it should continue
to diminish. For that reason, the small craft advisory for the
Caribbean waters and local passages as well as the nearshore
Atlantic waters were canceled. But, the small craft advisory
continues for the Atlantic offshore waters until 8PM AST tonight.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 85 75 83 73 / 20 50 50 20
STT 85 74 83 74 / 20 50 50 20

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
323 PM AST Sat Mar 11 2017

.SYNOPSIS...A surface high pressure across the northeastern
Atlantic, will continue to drift rapidly northeastward well away
of the local islands tonight and Sunday. As this happens, the
local winds will continue to decrease across the region. The wind
flow will continue to transport small patches of cloudiness and
showers across the local islands. A mid to upper level ridge is
expected to remain as the main weather feature across the region
for the next several days, maintaining a dry and stable weather
pattern across the local islands.

&&

.SHORT TERM...This evening through Monday...The east southeast
low level wind flow will continue to transport small patches of
moisture across the eastern sections of Puerto Rico and the U.S.
Virgin Islands overnight and early Sunday morning followed by
locally induced afternoon convection across western, interior and
northwest sections of Puerto Rico Sunday afternoon. However, no
significant precipitation is expected as a dry and stable air mass
will remain across the region. The mid to upper ridge is expected
to remain as the main weather feature across the region, limiting
the showers development. The minimum temperatures tonight are
expected to range between the mid to low 70s in the coastal areas
and around the low 60s across the mountainous areas.

.LONG TERM...Tuesday through Monday...A mid to upper level ridge
is expected to remain across the local islands through most part
of the work week. This feature will continue to limit the shower
activity across the local islands. However, the local wind flow
will continue to transport small patches of moisture and brief
periods of showers across the eastern sections of Puerto Rico,
Vieques, Culebra and the U.S. Virgin Islands during the nights and
early in the mornings, followed by locally induced convection each
afternoon over interior, western and northwest Puerto Rico. Model
guidances suggests that a frontal boundary will reach our
Atlantic coastal waters on Friday, but some areas of moisture
associated with the frontal boundary is expected to reach the
forecast area, inducing an increase in cloudiness and shower
across the region. However, not widespread or significant
precipitation is expected at this time.

&&

.AVIATION...SHRA over western PR expected to end around sunset. This
will create tempo MVFR at TJMZ/TJBQ flying area. Streamers
developing off the Leeward/USVI terminals and across eastern PR
should result mainly in VCSH across the rest of the terminals with
brief -RA periods. Sea breeze variations will continue through at
least 22z. Then low level winds will continue at 10-15 kts.

&&

.MARINE...Seas will continue to slowly improve across the regional
waters tonight. Latest buoy observations are indicating seas of
2-4 feet across the near shore coastal waters and east to east
southeast winds at around 15 knots. Across the offshore waters
seas up to 7 feet are expected to continue through at least
tonight and therefore the small craft advisory continues for the
Atlantic offshore waters until 8PM AST tonight.

&&

Fire danger statement continues in effect through at least 5 pm
for the southern coastal plains. Favorable fire weather
conditions with RH`s in the low to mid 40s and sustained winds at
15 mph and higher are expected for the next few days.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 74 83 73 85 / 50 50 20 20
STT 74 83 74 84 / 50 50 20 20

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
458 AM AST Sun Mar 12 2017

.SYNOPSIS...Surface high pressure across the northeastern
Atlantic will continue to drift to the NE further into the NE
Atlantic for the next few days, meanwhile there will be a surface
low that will enter the western Atlantic over the next few days,
which will help relax the local pressure gradient a bit more.
Ridge aloft should keep a stable atmosphere locally, which will
cause the shower development to be induced due to the combination
of the local effects, diurnal heating and available moisture. A
patch of moisture is expected to affect the southern half of PR in
the morning and then central and western PR in the afternoon while
the rest of the local area should have near normal available
moisture.

&&

.SHORT TERM...Sunday through Tuesday...

In general, fair weather conditions prevailed across the islands
overnight. Satellite imagery showed a layer of clouds over the
islands and the Doppler Radar detected a few sprinkles across the
local waters, eastern Puerto Rico and St Croix overnight. The
Doppler Radar detected more frequent shower activity early this
morning, as a surge of moisture arrived from the east. Once again,
the local temperatures were between the mid and low 70s along the
coastal areas and around the low 60s in the mountainous areas.

A moist air mass is expected to move across the islands today. As a
result, shower activity should increase through the morning hours.
Showers are expected to affect the east half portion of the CWA,
which include eastern PR and the U.S. Virgin Islands, as well as the
surrounding waters. Then, the combination of the available moisture,
local effects and diurnal heating will enhance afternoon convection
along the Cordillera Central and west Puerto Rico, as well as
downwind from the U.S. Virgin Islands and into the eastern sections
of PR.

Under a ridge pattern aloft, the regional weather pattern will be
driven by low level moisture advection. As a result, trade wind
showers will continue at times across the windward areas Monday and
Tuesday. In addition, locally induced afternoon showers across west
Puerto Rico are also expected each day.

.LONG TERM...Tuesday through Monday...

As the aforementioned SFC low enters the western Atlantic and
moves to the north northeast, the local pressure gradient will be
more relaxed and a frontal boundary will be to the north northwest
of the local islands. This pattern will develop early this week
but the local impact will be minimal until probably late Friday
or early Saturday and throught the weekend. As of now, we expect
mainly easterly winds with typical brief showers in the overnight
and morning hours with showers developing across western PR in the
afternoon, keeping the USVI with isolated to scattered brief
showers through the day. This pattern should also cause seasonable
temperatures to prevail.

Late into the forecast period, the long term guidance is now
suggesting that the frontal boundary that is expected to be
present to the north-northwest of the local islands will move in
and affect the local islands this weekend, bringing considerable
moisture and causing northerly winds by Sunday. No too much detail
to expand on at the moment as confidence is low due to how far
into the forecast period this is and the fact that the long term
guidance has been flop-flopping on this frontal boundary for the
past few days.

&&

.AVIATION...VFR conds through the morning hours. SHRA will move
en route btwn PR/USVI and the Leeward islands. Mountain obsc and
SHRA/+SHRA are expected across the interior and Western Sections
of PR btwn 12/16-23z. Therefore, BKN-OVC ceilings at FL020-FL090,
as well as MVFR or even brief IFR conds are possible at TJMZ/TJBQ.
Also, TJSJ/TIST/TISX can expect brief passing -SHRA/SHRA. Calm to
light and variable winds til 12/12z, becoming from the E t 10 to
17 kt with higher gusts and sea breeze variations.

&&

.MARINE...Small craft operators should exercise caution as seas
will be up to 6 feet today. The local winds are expected to be up
to 15 knots. Local guidance is suggesting a northerly swell to
invade the local waters late on Sunday into Monday, possibly
causing hazardous seas. Given how much the models have struggled
to accurately forecast northerly swells over the mast few weeks,
it is not out of the realm of possibilities to actually have seas
up to 7 feet across out local Atlantic waters early next week.
There is a moderate risk of rip currents across many of our local
beaches, please refer to our Surf Zone Forecast for more details
on the rip currents and breaking wave heights.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 83 74 86 75 / 40 20 20 30
STT 84 74 84 74 / 40 20 20 30

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
422 PM AST Sun Mar 12 2017

.SYNOPSIS...A surface high pressure across the northeastern
Atlantic, will continue to drift rapidly northeastward well away
of the local islands tonight and Monday. As this happens, the
local winds will continue to decrease across the region. The wind
flow will continue to transport small patches of cloudiness and
showers across the local islands. A mid to upper level ridge is
expected to remain as the main weather feature across the region
for the next several days, maintaining a dry and stable atmosphere
across the local islands. A low pressure system and its associated
cold front is expected to emerge over the southwest Atlantic
Tuesday.

&&

.SHORT TERM...This evening through Tuesday...The easterly wind
flow will continue to transport small patches of moisture across
the eastern sections of Puerto Rico and the U.S. Virgin Islands
overnight and early Monday morning followed by locally induced
afternoon convection across western and interior sections of
Puerto Rico Monday afternoon. However, no significant
precipitation is expected as a dry and stable air mass will remain
across the region. The mid to upper ridge is expected to remain
as the main weather feature across the region for the next few
days. limiting the showers development. The minimum temperatures
tonight are expected to range between the mid to low 70s in the
coastal areas and around the low 60s across the mountainous areas.
Not significant changes in the present weather pattern is
expected across the region in the short term.


.LONG TERM...Wednesday through Tuesday...
A mid to upper level ridge is expected to remain across the local
islands through most part of the work week. This feature will
continue to limit the shower activity across the local islands.
However, the local wind flow will continue to transport small
patches of moisture and brief periods of showers across the
eastern sections of Puerto Rico, Vieques, Culebra and the U.S.
Virgin Islands during the nights and early in the mornings,
followed by locally induced convection each afternoon over
interior and western Puerto Rico. A low pressure system and its
associated cold front is expected to emerge over the southwestern
Atlantic early in the week. Model guidances suggests that the
associated frontal boundary will reach our Atlantic coastal
waters Friday and Saturday, but some areas of moisture associated
with the boundary is expected to reach the forecast area,
inducing an increase in cloudiness and shower across the region.
However, not widespread or significant precipitation is expected
at this time.

&&

.AVIATION...Tempo MVFR conditions at TJMZ/TJBQ through 22z due
to +SHRA. VCSH due to streamers across the Leeward/USVI and eastern
PR terminals, but overall VFR trough the forecast period. Sea breeze
variations at 12-18 kts will continue through at least 22z. Light
and variable winds at the surface overnight...increasing from the
east at 10-15 kts after 13/13z.

&&

.MARINE...Coastal buoys across the surrounding waters of PR and
the USVI are indicating up to 6 feet and east winds around 15 kts
with some higher gusts. Small crafts should continue to exercise
caution across the offshore waters due to 6 ft seas. Seas are
expected to becomes hazardous again Tuesday and Wednesday as a NE
swell invades the Atlantic waters. A moderate risk of rip
currents continue for much of the beaches of all islands tonight,
but a high risk of rip currents is expected for the northwest to
northeast beaches of Puerto Rico early Monday morning.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 74 86 75 84 / 10 20 30 20
STT 74 84 74 84 / 10 10 30 20

&&

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
456 AM AST Mon Mar 13 2017

.SYNOPSIS...Mid to upper level ridge will build over the region
through Wednesday. This high pressure aloft will maintain a fairly
stable air mass over the region. Although...a few passing showers
will move across the islands at times...a fair weather pattern
will prevail most of the time. A frontal boundary will reach the
islands early next week...bringing cloudiness and showers to the
region.

&&

.SHORT TERM...Today though Wednesday...
Dry weather conditions prevailed across Puerto Rico and the U.S.
Virgin Islands overnight. A slot of dry air moved across the local
islands. Very little shower activity was observed over land areas.
This dry weather conditions are expected to prevail most of the
day today, with only some light passing showers affecting the
local region from time to time.

By Tuesday, a patch of low level moisture embedded in the trade
winds is expected to affect the local region, increasing somewhat
the chances for showers across the area. Cloudiness with showers
will linger across the region Wednesday.


.LONG TERM...Thursday through Tuesday...
Strong surface high pressure over the Eastern Atlantic will bring
some Saharan Dust particles on Thursday. Mid to upper level ridge
will hold through Friday. A series of low pressures will amplify
over the Western Atlantic during the weekend...eroding the mid-
upper level ridge. At low levels...frontal boundary will approach
the forecast area from the north between Sunday and Monday. As a
result...moisture transport will be enhanced early next week in
response to the surface front.

&&

.AVIATION...VFR conditions are expected to prevail across all TAF
sites through at least 13/22z. Some light passing showers can be
expected in the vicinity of TIST, TISX and TJSJ during the morning
hours. Low level winds will be mainly east at 10 to 15 kts except
for sea breeze variations in coastal areas.

&&

.MARINE...Seas are subsiding across the coastal waters this morning.
However...seas are forecast to increase to 5-7 feet tonight into Tuesday...
resulting in a Small Craft Advisory across the waters of Northern Puerto
Rico from tonight through Tuesday Night. This will also result in
a high risk of rip current across the north facing beaches of Puerto
Rico on Tuesday. Seas of 3-5 feet with occasional seas of 6 feet will
return Wednesday and Thursday.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 85 74 85 74 / 20 30 20 20
STT 85 74 84 74 / 10 30 20 30

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
357 PM AST Mon Mar 13 2017

.SYNOPSIS...
A mid to upper level ridge is expected to strengthens and remains
as the main weather feature across the northeast Caribbean
through at least the end of the work week. This feature will
continue to maintain the area under a generally dry and stable
atmosphere. Small patches of moisture embedded in the trades will
continue to produce few brief passing shower across the local
islands, but most of time a fair weather pattern will prevail. A
low pressure system and its associated cold front is expected to
emerge over the northwest Atlantic by the upcoming weekend.

&&

.SHORT TERM...This evening though Wednesday...
A generally dry and stable weather pattern is expected to continue
across the local islands during the period. Doppler weather radar
indicated only isolated showers mostly across the surrounding
waters. This moisture is expected to combine with daytime
heating, sea breeze convergence and other local effects to induce
the development of scattered showers across western interior and
northwest Puerto Rico each afternoon. A dry weather pattern is
expected elsewhere across the region as a mid to upper level ridge
remains as the main weather feature across the northeast
Caribbean. Not significant changes in the present weather pattern
is expected across the region in the short term.

.LONG TERM...Thursday through Wednesday...
A mid to upper level ridge is expected to strengthens even more
and remains as the main weather feature across the region through
the rest of the work week. This feature will continue to limit the
shower activity across the local islands. However, the local wind
flow will continue to transport small patches of moisture and
brief periods of showers across the eastern sections of Puerto
Rico, Vieques, Culebra and the U.S. Virgin Islands during the
nights and early in the mornings, followed by some locally induced
convection each afternoon over interior and western Puerto Rico.

A low pressure system and its associated cold front is expected
to move over the northwestern Atlantic by the upcoming weekend.
Model guidances suggests that the associated frontal boundary or
frontal boundary remnants will reach our Atlantic coastal waters
Saturday and Sunday. Some areas of moisture associated with the
boundary is expected to reach the forecast area, inducing an
increase in cloudiness and shower across the region.

&&

.AVIATION...VFR conds are expected to prevail at all TAF sites
through the forecast period with brief MVFR conds possible in and
around JMZ/JBQ in limited SHRA. Easterly winds at 10 to 15 kts
expected except for sea breeze variations in coastal areas. Light
and variable winds expected overnight.

&&

.MARINE...Seas will begin to deteriorate tonight into late Tuesday
as the trade winds slightly increase and a northerly swell
invades and spreads across the local Atlantic waters.

&&

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

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
511 AM AST Tue Mar 14 2017

.SYNOPSIS...
Mid to upper level ridge is expected to strengthens today over the
region and continues through the week. The ridge aloft will favor
a stable atmosphere resulting in fair weather conditions with
limited shower activity. However, surges of low level moisture
will reach the islands at times. Therefore shower activity cannot
be ruled out each day. A frontal boundary will move near the
islands early next week...bringing some cloudiness and showers to
the region.

&&

.SHORT TERM...
An upper level ridge across the southeast Caribbean will move
east across Puerto Rico and the U.S. Virgin Islands Tuesday night
to the Leeward Islands by Friday. The high from the central
Atlantic will extend across Jamaica and then shift north during
the week to maintain moderate to fresh easterly trade wind flow.
Although general drying will continue, it will be mostly at mid
levels now through Saturday. But lower level moisture will be
sufficient to generate showers in western Puerto Rico and possibly
downstream from El Yunque each day beginning around noon.

.LONG TERM...Friday through Wednesday...
A couple of upper level trough are forecast to swing north of the
region across the Atlantic waters on Friday and Sunday. This will
erodes the Upper level ridge. A frontal boundary is expected to
move near the region by the end of the weekend and into the
upcoming week. As the boundary reach the region, moisture pooling
is expected to increase each day and could enhance shower activity
across the islands.

&&

.AVIATION...
VFR conds are expected to prevail at all TAF sites through the
forecast period with brief MVFR conds possible in and around
TJMZ/TJBQ in limited SHRA. Mtn obscurations are expected in
central and wrn PR btwn 14/16-15/02Z. Expect easterly winds at 10
to 15 kts with sea breeze variations in coastal areas. Winds alf
easterly 10 to 20 kt up to FL110 then northerly 10 to 20 kt up to
FL280. Maximum winds west 35 to 40 kt from FL360-460.

&&

.MARINE...
Marine conditions are expected to deteriorate today, due to
moderate to locally fresh trade winds and a northerly swell
affecting the Atlantic waters. Seas up to 7 feet are expected
across the Atlantic Offshore waters and Anegada Passage. Therefore
a small craft advisory is in effect across the Atlantic Offshore
Waters and the Anegada passage. Elsewhere, small craft operators
should exercise caution due to seas at 6 feet or less.

For the beach goers, there is a high risk of rip currents across
the Atlantic waters of Puerto Rico. The risk of rip currents
across the U.S. Virgin Islands is moderate. Please refer to the
latest Surf Zone Forecast (SRFSJU) issued by WFO San Juan PR for
the latest and up to date info.



&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 81 75 81 75 / 20 20 10 20
STT 78 77 78 77 / 20 30 20 40

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
317 PM AST Tue Mar 14 2017

.SHORT TERM...A strong mid to upper level ridge is expected to
remains as the main weather feature across the northeast
Caribbean through at least the end of the work week. This feature
will continue to maintain the area under a generally dry and
stable atmosphere. Small patches of moisture embedded in the
trades will continue to produce few brief passing shower across
the local islands, but most of time a fair weather pattern will
prevail. A low pressure system and its associated cold front is
expected to emerge over the northwest Atlantic early in the
weekend.

&&

.SHORT TERM...This evening though Thursday...
Limited shower activity was observed over land areas this
afternoon. Only isolated showers were detected in streamers across
the waters between the U.S. Virgin Islands and Puerto Rico. This
limited moisture is expected to combine with daytime heating, sea
breeze convergence and other local effects to induce the
development of scattered showers across western interior and
northwest Puerto Rico this afternoon. A generally dry and stable
weather pattern is expected to continue across the local islands
during the period as a mid to upper level ridge remains as the
main weather feature across the northeast Caribbean. Not
significant changes in the present weather pattern is expected
in the short term.

LONG TERM...Friday through Thursday...
A strong mid to upper level ridge is expected to remains as the
main weather feature across the region through the rest of the
work week. This feature will continue to limit the shower activity
across the local islands. However, the local wind flow will
continue to transport small patches of low level moisture moisture
and brief periods of showers across the eastern sections of
Puerto Rico, Vieques, Culebra and the U.S. Virgin Islands during
the nights and early in the mornings, followed by some locally
induced convection each afternoon over interior and western Puerto
Rico.

A low pressure system and its associated cold front is expected
to move over the northwestern Atlantic by the upcoming weekend.
Model guidances suggests that the associated frontal boundary or
remnants will reach our Atlantic coastal waters Sunday and Monday,
eroding the mid to upper level ridge. Some areas of moisture
associated with the boundary is expected to reach the forecast
area, inducing an increase in cloudiness and shower activity across
the region.

&&

.AVIATION...-SHRA across W PR should dissipate by 22z. Mainly VFR
expected across all terminals through the forecast period. Light and
variable winds expected overnight...increasing from the east at 10-
15 kts after 15/13z.

&&

.MARINE...Seas will continue to recede across the Atlantic
coastal waters tonight. A high rip current risk continues in
effect for the northern beaches of the islands and Culebra. A
moderate risk persist for the rest of the beaches of all islands.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 74 81 75 82 / 20 10 20 30
STT 74 78 77 78 / 20 20 40 40

&&

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
523 AM AST Wed Mar 15 2017

.SYNOPSIS...
A mid to upper level ridge will continue to result in stable
weather conditions through the workweek. At the surface, a trough
is forecast to moves from the east into the local Caribbean waters
by early Thursday morning. As this trough reach the islands
surface moisture, clouds and trade wind showers are expected to
increase somehow. However, a fair weather pattern is expected to
dominate most of the time through this period.

The ridge pattern aloft is forecast to weakens by the upcoming
weekend into next week. A surface low pressure system and its
associated cold front is expected to moves northwestward across
the Northwestern Atlantic early this weekend.

&&

.SHORT TERM...
High pressure aloft drifts slowly eastward over the
Leeward Islands today through Saturday. Underneath several short
wave troughs move through the area, one on Wednesday night and
Thursday and the other late Friday night. Each will carry an
increase in clouds and showers. High pressure in the northeast
central Atlantic today will be reinforced by additional high
pressure invading the western Atlantic later in the week. This will
maintain moderate to fresh east northeast to east southeast trade
winds across the area. Before the first surface trough moves into
the area, however, drier air will prevail and there will be weak
capping at 700 mb.

.LONG TERM...Saturday through Thursday...
At the surface, a low pressure system and associated frontal
boundary is expected to move over the Northwestern Atlantic. The
ridge aloft is forecast to weakens as a mid to upper level trough
swing by the Atlantic waters by the end of the weekend into next
week. If this weather pattern is correct, showers and cloudiness
are forecast to increase as instability and surface moisture
increase over the islands. Model guidance are suggesting moisture
pooling above the normal values for this time of the year, as
well as the possibility of thunderstorm activity by early next
week.

&&

.AVIATION...
Moisture associated with a surface trough will move into
the Caribbean sea south of the forecast area btwn 15/18-16/00z
spreading sct SHRA across the area. Brief periods of MVFR are
possible at TKPK, and at TJMZ aft 15/18z. Expect mtn obscurations
after 15/16z. SHRA are also expected to develop ovr west and
northwest PR aft 15/18z. Winds NE-E 10 to 20 kt up thru FL200.
Maximum wind west 40 kt at FL410.

&&

.MARINE...
Buoys across the coastal waters of the islands are indicating
seas between 3 and 5 feet and easterly winds around 10 knots.
Small craft operators should exercise caution across the offshore
waters and Caribbean Passages due to seas up to 6 feet. In
addition, a small craft advisory is in effect for the Atlantic
Offshore waters and Anegada passage from this evening.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 86 74 87 75 / 10 40 40 40
STT 85 74 84 73 / 10 40 40 40

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
Issued by National Weather Service Melbourne FL
241 PM AST Wed Mar 15 2017

.SHORT TERM...Winds over the open waters are forecast to increase
overnight and early Thursday in response to a wave moving across
the area embedded within the easterlies. Scattered light to
moderate showers will be possible mainly along the windward
portions of the islands tonight and into Thursday morning as the
feature moves across the region along with an increase in
cloudiness. Measurable rain in affected areas should remain a
tenth to two tenth of an inch at most with most locations below a
tenth of an inch.

High pressure will continue to be the primary larger scale
feature over the western basin through late in the week. This will
maintain moderate to fresh east northeast to east southeast trade
winds across the area and drier air will prevail from mid day
Thursday onward with capping due to subsidence at 700 mb and
higher.

.LONG TERM...Saturday through Thursday...
(from previous discussion) The ridge aloft is forecast to weaken
as a mid to upper level trough swing by the Atlantic waters by the
end of the weekend into next week. If this weather pattern is
correct, showers and cloudiness are forecast to increase as
instability and surface moisture increase over the islands. Model
guidance are suggesting moisture pooling above the normal values
for this time of the year, as well as the possibility of
thunderstorm activity by early next week.

&&

.AVIATION...
Moisture associated with the approaching wave will move into the
Caribbean sea along and south the area btwn through tonight,
spreading sct SHRA across the area, especially along windward
facing locations. Brief periods of MVFR are possible at TKPK, and
at TJMZ aft 15/18z.

&&

.MARINE...
Anticipated wind increase with gusts near to above 20 kts over
the waters tonight wl keep likelihood of advisory conditions
developing over the open waters beyond the immediate coastline
later tonight. In the meantime small craft operators should
exercise caution this evening across the offshore waters and
Caribbean Passages due to seas up to 6 feet. Advisory conditions
are expected to continue over the open waters N of PR through
Friday.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 74 87 75 84 / 40 40 40 30
STT 74 84 73 84 / 30 30 40 30

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
518 AM AST Thu Mar 16 2017

.SYNOPSIS...
A strong mid to upper level ridge continues dominating the local
weather. This feature will holds over the region through early
Saturday. In general, a fair and stable weather pattern is
expected to persist through the rest of the work week. However, a
weak surface trough with a surge of moisture is moving across the
Caribbean waters from the east today. Therefore, passing showers
are expected across the U.S. Virgin Islands and the eastern half
portion of Puerto Rico during the morning hours, followed by
afternoon convection across the interior and west PR. By the
upcoming weekend into next week, a frontal boundary will aid in
moisture pooling across the region. Local instability will begin
to increase as a mid to upper level trough swing by the region.

&&

.SHORT TERM...
High pressure aloft will dominate the eastern and
southern Caribbean and winds will remain west to west northwest.
After a trough from the east passes through Puerto Rico today,
somewhat drier air with traces of Saharan dust will move through
today and tomorrow. This, and drier mid layers, will limit shower
activity. Nevertheless showers are expected each day. In northwest
Puerto Rico today and in western Puerto Rico later Friday and
Saturday when another area of moisture moves into the area. Winds
will become more northeasterly at the surface through 700 mb late
Friday and this should favor showers on the northeast half of Puerto
Rico and the Luquillo range--especially during the morning hours
Friday and Saturday. Moisture is limited this week and accumulations
will be light..

.LONG TERM...Sunday through Friday...
A trough aloft is forecast to swing across Atlantic Ocean
increasing local instability. A second frontal boundary will
provide the last push to enhance moisture pooling across the
islands by Sunday or early next week. Model guidance is suggesting
moisture values between percentiles 75th and 99th for March. If
this weather pattern is right, showers and cloudiness will
increase over the islands. In addition, this weather pattern could
support the formation of thunderstorm activity through the
upcoming week.

&&

.AVIATION...
Drier air behind a sfc trof is expected over the eastern
portion of the forecast area from TJNR to TKPK thru 17/04z and VFR
conds with few SHRA will prevail. Isold SHRA are expected ovr ern PR
thru 16/14Z. Then aft 16/17z sct SHRA and mtn obscurations will dvlp
over wrn and interior PR affecting mainly TJMZ and TJBQ with brief
MVFR for CIGS that may last until 17/00z. Winds will be east 10 to
18 kt with sea breeze variations. Winds alf will be easterly 10 to
20 kt up thru FL220. Maximum winds west at 35 kt at FL400.

&&

.MARINE...
A weakly induced surface trough is moving across the Caribbean
waters as a cold front continues eastward across the western
Atlantic. Small craft operators should exercise caution across the
regional waters due to seas up to 6 feet and winds between 15 and
20 knots. Seas are expected to increase across the Atlantic
Offshore waters at up to 7 feet. As a result, a small craft
advisory is in effect for this waters.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 86 74 85 75 / 30 40 20 50
STT 85 73 85 74 / 30 40 20 40

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
320 PM AST Thu Mar 16 2017

.SYNOPSIS...A mid to upper level ridge across the forecast area
is expected to erode during the next several days. Meanwhile,
continue to expect mainly fair and stable weather conditions
Fri-Sat. Under trofiness aloft and plenty of moisture, there is
a higher chance for shower activity early next week.

&&

.SHORT TERM...Tonight through Sat...
A mainly fair and stable weather pattern is expected to prevail
across the local islands tonight through at least Saturday under
a mid to upper level ridge pattern. However, a few showers embedded
in the trades may reach the local area to result in brief passing
showers across windward areas. Locally induced afternoon showers
are also possible across west PR each afternoon due to sea breeze
convergence. Surface high pressure across the central Atlantic and
a dissipating surface front northwest of the area will continue
to promote easterly winds Fri, becoming northeasterly Sat as
another surface high establishes across the west Atlantic.
Therefore, seasonable temperatures will continue to prevail Fri,
with pleasant temperatures expected on Sat. The chance for shower
activity will increase early next week as the ridge aloft erodes
in response to a trough moving across the Atlantic Ocean.



.LONG TERM...Sun through Fri / issued 518 AM AST Thu Mar 16 2017
A trough aloft is forecast to swing across Atlantic Ocean increasing
local instability. A second frontal boundary will provide the
last push to enhance moisture pooling across the islands by Sunday
or early next week. Model guidance is suggesting moisture values
between percentiles 75th and 99th for March. If this weather
pattern is right, showers and cloudiness will increase over the
islands. In addition, this weather pattern could support the
formation of thunderstorm activity through the upcoming week.


&&

.AVIATION...VFR conds expected across the local terminals expected.
Afternoon convection will cause SHRA development around TJMZ and
TJBQ. MVFR conds possible for TJMZ and TJBQ between 16/19-22Z under
the expected SHRA, while VCSH is likely. Winds will continue from
the east southeast with sea breeze variations at 10-15kt today,
decreasing and becoming more easterly after 16/23Z.

&&

.MARINE...A northerly swell and increasing winds will cause waters
to become hazardous tonight through the weekend. Seas are expected
to increase across the Atlantic Offshore waters near 7 feet tonight.
As a result, a small craft advisory is in effect for this waters.
A high risk of rip currents is also expected across the Atlantic
shoreline of local islands Fri.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 74 84 75 84 / 20 20 50 50
STT 73 84 74 84 / 30 30 50 50

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
508 AM AST Fri Mar 17 2017

.SYNOPSIS...A mid to upper level ridge across the area will drift
east and erode today through Sunday allowing a cold front to
approach the area from the northwest. Although trade winds will
continue during the entire period, flow will become more
southeasterly during the week next week and moisture will steadily
increase tonight through Monday and again on Friday and Saturday
of next week. This will increase the chances and coverage of
showers and allow thunderstorms to develop next week.

&&

.SHORT TERM...Today through Sunday
Under a mid to upper level ridge pattern a mostly fair and stable
weather pattern is expected to continue across the local islands
this morning through at least early Sunday. However, small areas of
moisture embedded in the trades may reach the local islands from
time to time to produce brief passing showers across the U.S.
Virgin Islands and eastern sections of Puerto Rico each morning.
Locally induced afternoon showers are also possible across western
and interior sections of Puerto Rico during the afternoons due to
sea breeze convergence. Surface high pressure across the central
Atlantic and a frontal boundary north northwest of the area will
continue to promote an easterly wind flow across the region today.
Winds are expected to become east northeast on Saturday as the
frontal boundary remnants move across the local Atlantic waters.
Therefore, seasonable temperatures will continue to prevail today
with pleasant temperatures expected on Saturday. The chance for
shower activity will increase late Sunday and early next week as
the ridge aloft erodes and the frontal remnants reach the region.

.LONG TERM...Sunday night through Saturday
Low pressure will move off the eastern coast of the United States
on Saturday evening. The cold front that accompanies it will
reinforce the stalled frontal boundary that will have stalled
across the windward passage on Monday. This will enhance the
upward vertical motion ahead of the front over the area and begin
to pull moisture in from the tropical western Atlantic possibly as
early as Sunday afternoon. Current model solutions do not bring
the front or its associated shearline over the forecast area but
the increased moisture and dynamics are expected to generate
isolated thunderstorms and increased shower activity mainly Monday
and Tuesday and Friday and Saturday. Moisture in the GFS solution
peaks either Friday afternoon or Saturday of next week depending
on the model cycle, but this should be the wettest period of the
week. It is too early to tell if flooding could result but some
local urban and small stream flooding should be expected on Monday
and Tuesday and again on Friday and Saturday of next week.

&&

.AVIATION...Mostly VFR condition expected across the local
flying area. VCSH are possible this morning across the Leewards,
USVI and eastern PR taf sites. Afternoon convection will cause
SHRA development around TJMZ and TJBQ. Winds will continue from
the east with sea breeze variations at 10-15kt today, decreasing
and becoming more from the ENE after 17/23Z.


&&

.MARINE...Models have been over estimating sea heights, but buoy
41043 has remained over 7 feet for some time now due to easterly
winds. Expecting seas to increase tonight and Saturday in response
to stronger winds, but subside by Sunday. Seas will likely remain
7 feet or better in the northern part of the outer Atlantic zone
through Sunday. Seas will also likely return by mid week next
week.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 86 75 85 74 / 20 50 50 50
STT 84 73 84 74 / 30 50 50 50

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
320 PM AST Fri Mar 17 2017

.SYNOPSIS...A generally fair and mainly stable weather pattern is
expected to prevail tonight and early the upcoming weekend under
a weakening ridge aloft. Moisture and instability will increase
late Sunday night and into early next workweek as a broad mid to
upper level trough and associated surface front/prefrontal trough
moves closer to the forecast area.

&&

.SHORT TERM...Tonight through Sunday...
A mid to upper level ridge across the forecast area will continue
to erode. As a result, moisture is expected to pool across the
local islands late the upcoming weekend. A surface high across
the central Atlantic and a dissipating surface front northwest of
the area will continue to promote moderate easterly winds through
the weekend. As a result, under a weakening ridge aloft and easterly
winds, expect passing showers across windward areas in the morning
and evening hours followed by locally induced showers across
western Puerto Rico each day.

.LONG TERM...Monday thru Day 8 / issued 508 AM AST Fri Mar 17 2017
As a broad mid to upper level trough moves across the western and
central Atlantic, its associated surface front and prefrontal
trough will approach the local islands early next week. This will
bring moisture and instability across the forecast area to result
in a wetter pattern early next week. By the end of the week, a
mid to upper level trough will develop across the Gulf of Mexico
and the western Caribbean to keep instability and plenty of
moisture across the eastern Caribbean.

&&

.AVIATION...Mainly fair weather expected today so VFR conds should
prevail. Mainly easterly winds today with sea breeze variations at
10-15kt and a few gusts expected through 17/23Z. There is a chance
for VCSH across TJMZ and TJPS after 17/18Z. Winds will weaken
slightly after 17/23Z but remaining from the east with ISOLD/SCT
SHRA across the local area, which could cause VCSH across the local
terminals except for TJMZ during the overnight hours.

&&

.MARINE...A northerly swell and increasing winds will cause waters
to become hazardous tonight through the upcoming weekend. Small
Craft Advisories are in effect for most of the local waters due
to seas 7 to 8 feet and moderate winds. A high risk of rip currents
is also expected across the Atlantic shorelines of local islands
during the upcoming weekend.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 75 85 74 86 / 50 50 20 30
STT 73 84 74 83 / 50 50 50 50

&&

[cycloneye]

Area Forecast Discussion...CORRECTED
National Weather Service San Juan PR
454 AM AST Sat Mar 18 2017

.SYNOPSIS...A weak trough moving through the area this morning
will bring isolated to scattered showers and a herald of
increasing moisture to come beginning Sunday morning. The approach
of a shear line Monday and Tuesday will bring increasing shower
activity. The approach of the tail of an upper level jet will
bring increasing instability, moisture and showers Friday and
Saturday and that moisture will linger beyond next weekend.

&&

.SHORT TERM...Overnight through early Monday...
A mid to upper level ridge across the forecast area will continue to
erode, as a polar trough will amplify and move eastward across the
western Atlantic. As a result, the trade wind inversion will
weaken and allow low Level moisture to pool and converge across
the region during the weekend and into the early part of next.
Strong surface high centered across the central Atlantic and a
cold frontal boundary northwest of the area will induce moderate
easterly winds across the region today through early Sunday. The
weak ridging aloft and the prevailing easterly winds will support
periods of passing early morning showers, followed by locally and
diurnally induced afternoon convection across parts of the islands.
However, the majority of the afternoon showers should be focused
over parts of the interior and west sections of Puerto Rico. By
late Sunday and through early Monday, low level winds are to then
become more southeasterly as a surface trough will develop and
move across the region. This will increase moisture convergence
allowing a wetter pattern and better chance for morning and afternoon
convection.

.LONG TERM...Monday through Sunday, 26 March...
A shear line will pass through Puerto Rico and the U.S. Virgin
Islands on Monday ending the southeast flow at the surface. This
will bring showery weather to the area. The best moisture will be
pulled to the northeast of the area along the front, but some
instability could produce numerous showers and isolated
thunderstorms in the interior of Puerto Rico. The easterly flow
that follows will bring continued showers Monday night in residual
moisture--mainly to the mountains of southeast Puerto Rico.
Precipitable water values decline some into Wednesday but remain
one third higher than they are now. The old boundary will be well
diffused over the area so the middle of the week will be wetter
and cloudier than this weekend. Wednesday through Sunday we will
be under the right entrance of the sub- tropical jet. This will
enhance vertical motion and cause precipitable water values to
rise to almost 2 inches by Friday and Saturday for another round
of showers and better chances for local urban and small stream
flooding. Moisture and cloudiness continue through the weekend as
the tail of the upper level jet remains just north of the area.

&&

.AVIATION...VFR conds durg prd. Low level wnd fm E to NE btw 10 to
20 kts blo FL200...bcmg W and incr w/ht abv. Max wnd around 45
kts nr FL400. Sfc wnds fm E-NE around 10 kts with ocnl hir gusts
along coastal areas and with passing SHRA. SCT-BKN nr
FL025...FL050... FL080 with isold passing -SHRA/SHRA few TOPS
FL100 til 18/12z en route btw islands. Brief mtn top obscr in
passing SHRA and low clds lyrs ovr E PR til 18/10z. Btwn
18/17z-18/22z MVFR cond psbl W aftn SHRA mainly ovr W PR Nr
TJBQ/TJMZ.


&&

.MARINE...Seas and swell will begin to subside tonight and by
Monday all small craft advisories should be down. Another swell
group from the next system to enter the western Atlantic ocean
will arrive from the northwest on Wednesday but current models are
holding significant wave heights down to 6 feet. The system that
rides in Friday and Saturday will bring much higher seas and the
GWW and WNA models suggest that wave heights could be in excess of
10 feet by next weekend.

Beach-goers should expect to be at high risk to rip currents along
coasts with northern exposures. Today and tonight, Wednesday and
next weekend for much the same reasons given above.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 85 74 86 73 / 50 30 30 30
STT 85 74 83 73 / 50 50 50 50

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
355 PM AST Sat Mar 18 2017

.SYNOPSIS...The chance for showers and thunderstorms will
increase during the upcoming week as plenty of moisture pools
across the area combined with favorable upper level dynamics.

&&

.SHORT TERM...Tonight thru Tue...
Ridge aloft will continue to erode as a broad mid to upper level
trough moves across the western and central Atlantic tonight-Sun.
At lower levels, moisture is expected to pool across the local
islands as a surface front and associated prefrontal trough
approaches the forecast area Mon-Tue. This feature will also
result in winds shifting south southeast by Monday, becoming more
east southeast on Tue. Therefore under this evolving pattern,
weather conditions will become favorable for shower activity
across the forecast area, particularly Mon-Tue. Passing showers
are expected to prevail across the USVI and eastern Puerto Rico,
spreading across north and west Puerto Rico each afternoon. The
afternoon activity across western sections of the island is
mainly associated to local effects and available moisture.

.LONG TERM...Wed thru Day 8 /issued 454 AM AST Sat Mar 18 2017...
Wednesday through Sunday we will be under the right entrance of
the sub-tropical jet. This will enhance vertical motion and cause
precipitable water values to rise to almost 2 inches by Friday
and Saturday for a round of showers and better chances for local
urban and small stream flooding. Moisture and cloudiness continue
through the weekend as the tail of the upper level jet remains
just north of the area.

&&

.AVIATION...Mostly VFR conditions expected during the forecast
period across the local flying area. VCSH are expected across the
Leewards, USVI and eastern PR taf sites. Winds will remain from the
E to ENE between 10 to 20 kts with higher gusts all the way from the
surface to 16k feet becomimg from the west and stronger aloft.
Between 18/17Z-18/22Z MVFR conditions are possible in SHRA mainly
near TJBQ and TJMZ.

&&

.MARINE...Seas and swell will begin to subside tonight through Sun,
however another swell group will arrive from the northwest on Wed.
Hazardous seas expected mainly across the offshore Atlantic waters.
A moderate to high risk of rip currents continues across the
Atlantic shorelines. Seas 6 to 8 feet through the weekend under
moderate easterly winds.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 74 86 73 85 / 30 30 40 50
STT 74 83 73 82 / 50 50 50 50

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
516 AM AST Sun Mar 19 2017

.SYNOPSIS...Increasing moisture, the presence of a cold front to
our north, a subtropical jetstream that holds just to our north
leaving us under favorable upper level dynamics will all
contribute to an increasingly wet scenario for Puerto Rico and the
U.S. Virgin Islands. Rainfall amounts should be highest on
Saturday, but rain is expected in many areas both early and late
in the week.

.SHORT TERM...Today thru Tuesday...
For the rest of the overnight and early morning hours, passing
showers with brief gusty winds can be expected across the local
waters, as well as along portions of the north and east coastal
sections of the islands. During the afternoon hours, the
prevailing east southeast winds should steer diurnally induced
shower activity across the interior and northern half of Puerto
Rico including portions of the San Juan Metro area. Some areas of
heavy rainfall will also be possible in the northwest. Mainly
isolated showers are expected across the U.S virgin islands during
the afternoon.

The mid to upper level ridge will continue to erode as a broad
polar trough will become amplified and move eastward across the
west and central Atlantic through Tuesday. The subtropical jet
will round the base of this trough Monday through Tuesday placing
the region on the divergent and unstable side of the jet max.
Gradually increasing pooling of moisture and low level convergence
is still forecast beginning later this evening through the early
part of the upcoming week. This is in response to the frontal
boundary northwest of the region and an associated induced trough
which will develop and lift across the region Monday through
Tuesday. This overall pattern will result in the easterly winds
becoming more south southeasterly by Monday, then east southeast
once again on Tuesday. Weather conditions will become fairly moist
and unstable on Monday through Tuesday, with favorable conditions
aloft for increased shower activity and enhanced convective
development across the forecast area.

&&

.LONG TERM...Wednesday through Monday 27 March
On Wednesday a weak high pressure ridge will be found in place
enabling easterly trade winds of moderate to fresh intensity to
continue. That ridge will give way before a strong high pressure
moving out of the eastern United States late Thursday. It will
give another push to the front to our northwest and reinvigorate
the easterly trade winds again through the upcoming weekend. This
will maintain the flow of moisture over the area. An upper level
trough will move from Cuba on Wednesday to just north of Puerto
Rico on Sunday but will flatten out considerably as it does so.
The associated sub-tropical jet just north of us will remain
north of us during the entire period but will destabilize the
atmosphere around us on account of our being in the divergent
right entrance region. Moisture will have peaked on Tuesday but
diminishes only a little on Wednesday and Thursday and will rise
considerably late Thursday and early Friday due to the moisture
flow mentioned earlier. The GFS has been consistent in bringing
precipitable water with values of 1.8 to 2.0 inches early Friday
through beyond Monday of the following week. This will bring a
considerable amount of rain to the area should the forecast hold.
It is too early to determine if conditions are conducive for flash
flooding but localized urban and small stream flooding are
certainly possible with the forecast conditions. We continue with
isolated thunderstorms during the week as the inversion is
expected to be removed by Wednesday. The atmosphere becomes very
moist in nearly the entire column beginning Thursday and cloudy or
mostly cloudy conditions should prevail into early next week.

&&

.AVIATION...Mostly VFR conds at all terminals til 19/15Z. SFC
wnds lgt/vrb becmg E-SE 10-15 kts aft 19/14z...except for local
sea breeze variations. Til 19/15z...Isold to Sct passing SHRA ovr
the coastal waters btwn PR and the nrn Leewards islands...SCT-BKN
lyrs nr FL025...FL050... FL100...with VCSH at most of the local
terminals except TJMZ. Mtn top obscr ovr E PR til 19/14z. Fm
19/17z-19/22z... SHRA dvlpmnt psbl ovr ctrl mtn range and NW PR
with VCSH at TJBQ/TJMZ/TJSJ with MVFR psbl.


&&

.MARINE...Winds and seas are diminishing and all small craft
advisories should be down by 2 AM AST Monday. The system now in
the western Atlantic and its associated cold front will send
northerly swell into the area on Wednesday. Seas may reach 7 feet
in the Atlantic waters and passages. Then the newly refreshed cold
front to our north will begin to send much stronger swell into
the area Friday night. Seas of 10 feet or more are still possible
with this system.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 86 73 85 75 / 30 40 50 50
STT 83 73 82 72 / 50 50 50 50

&&