Caribbean - Central America Weather

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
416 AM AST Mon Jan 22 2018

.Synopsis...Frontal boundary and associated shear line will remain
north of the region as it dissipates slowly today through Tuesday.
Mid to upper level ridge will hold across the region for the next
several days. Surface high pressure north of the area will maintain
moderate east to northeast trade winds across the forecast areas
through the period. A cold front and associated boundary is forecast
to sink southwards and approach the region by the upcoming weekend.

.SHORT TERM...Today through Wednesday...
Clear to partly cloudy skies prevailed across the local islands
overnight. A dissipating frontal boundary remains across the Atlantic
waters well northeast of the local islands. Terminal Doppler Radar
indicated only few showers across the Atlantic waters as well as across
the surrounding waters of the northern U.S. Virgin Islands. Not precipitation
was detected elsewhere across the region overnight and so far this morning.

A surface high pressure located across the Atlantic waters just to the
north of the region will continue as the main weather feature across
the local islands for the next couple of days. Trade winds will continue
to transport patches of low level moisture across the local islands
from time to time during the next couple of days. Small patches of
low level moisture embedded in the trades will continue to produce
brief passing showers across the U.S. Virgin Islands and eastern Puerto
Rico from time to time, especially overnight and early in the mornings
for the next couple of days. These showers will move quickly westward
with minimal rainfall accumulations. During the afternoons, some cloudiness
with showers are expected to develop across the interior and west sections
of Puerto Rico. The GFS model guidance suggests an increase in low level
moisture by the middle of the week.

.LONG TERM...Thursday through Tuesday of next week.
The upper level high pressure ridge will hold across the region through
Friday. However the prevailing easterlies will continue to transport
sufficient moisture across the region to support periods of passing
late evening and early morning showers, as well as isolated to scattered
afternoon convection. Saturday through Sunday, a polar trough will amplify
and spread eastward across the west and central Atlantic causing a slight
erosion of the upper level ridge. By Monday and Tuesday the mid to upper
level ridge will reestablish over the region and again limit shower
development.

In the meantime, the a cold front is forecast to move across the west
Atlantic and reach the local area by the upcoming weekend. Model guidance
continued to suggest a gradual increase in trade winds moisture during
the latter part of the week with more favorable conditions for moisture
convergence and shower development over the weekend, as the cold front
sinks southwards and stalls just north of the region by Sunday. Improving
weather conditions are however expected by Monday and Tuesday with a
return of more typical passing trade wind showers.

&&

.AVIATION...Mainly VFR conditions are expected across the local
flying area through the forecast period. Little to no shower activity
is expected until 22/15Z. Thereafter, SHRA will begin to develop affecting
mostly TJMZ between 22/18Z and 22/21Z. Easterly winds expected to increase
to about 15 kts with sea breeze variations developing after
22/14Z.

&&

.MARINE...A northerly swell and and moderate to locally fresh trades
winds will affect the local waters today but will continue to slowly
subside and diminish today through Tuesday. Due to the rough and
choppy seas, small craft advisories will remain in effect today for
the Atlantic, local passages and offshore Caribbean waters. Easterly
winds will prevail between 15 to 20 knots. For beach goers, the
high surf advisory has been cancelled as the breaking waves are
now expected to be less than 10 feet. However, high risk of rip
currents will continue for the northwest to north facing beaches
of Puerto Rico, Culebrita beach and also for Saint Thomas.

&&

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

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
341 PM AST Mon Jan 22 2018

.SYNOPSIS...A surface high pressure across the north Atlantic is
moving east and will strengthen over the course of the next few
days as it absorbs another surface high across the northeastern
Atlantic. Another surface high pressure will move into the
western Atlantic, north of the local area late this week. This
will keep mainly easterly winds across the local area for the next
few days, becoming east northeasterly and rather breezy towards
the end of the week. Upper ridge will continue over the local
islands for the next several days with an upper trough passing to
the north of the local area, digging a bit more to the east of
the Leeward Islands early next week. Frontal boundary is expected
to remain well north of the local islands early next week.

&&

.SHORT TERM...Tonight through Wednesday...
Easterly trade winds continue as high pressure retreats and is
absorbed into another high in the northwest Atlantic. The next
vigorous cold front is poised to move into the western Atlantic
Tuesday evening. Its best progress during the week will be made to
the east, so by Thursday it will still be a little over 400 miles
to our north northwest. At first we will see a continuation of
patches of low level moisture that will move through with
scattered showers and a slightly deeper low level moist layer, but
on Thursday flow will begin to turn northeast to bring in cooler
and slightly drier air from the central Atlantic. This will
diminish the showers over most of Puerto Rico, but may leave
scattered showers and cooler weather on the northeast coast.

At upper levels a weak trough is passing through the area and will
coincide with the back edge of the better moisture seen today--
though mainly in the Atlantic waters north of the islands. The
moisture returns Tuesday and Wednesday in spite of the ridge that
builds--albeit weakly. A second weaker trough will move through
Wednesday night and drier air will again move in from the northeast.
Mid levels remain quite dry.

.LONG TERM...Thursday through Tuesday of next week...

From previous discussion...
The upper level high pressure ridge will hold across the region through
Friday. However the prevailing easterlies will continue to transport
sufficient moisture across the region to support periods of passing
late evening and early morning showers, as well as isolated to scattered
afternoon convection. Saturday through Sunday, a polar trough will amplify
and spread eastward across the west and central Atlantic causing a slight
erosion of the upper level ridge. By Monday and Tuesday the mid to upper
level ridge will reestablish over the region and again limit shower
development.

In the meantime, the a cold front is forecast to move across the west
Atlantic and reach the local area by the upcoming weekend. Model guidance
continued to suggest a gradual increase in trade winds moisture during
the latter part of the week with more favorable conditions for moisture
convergence and shower development over the weekend, as the cold front
sinks southwards and stalls just north of the region by Sunday. Improving
weather conditions are however expected by Monday and Tuesday with a
return of more typical passing trade wind showers.


&&

.AVIATION...VFR conditions are expected at all TAF stations. SHRA in
wrn PR may produce brief MVFR conds til 22/21Z and mtn obscurations.
Winds east 8 to 16 kt with sea breeze influences til 22/21Z then
subsiding to less than 12 kt. SHRA will increase from east to west
arriving in ern PR arnd 23/09Z. Sea breezes return aft 23/14Z east 8
to 16 kt. Max winds west 35-40 kt FL420-500 diminishing aft
23/00Z.


&&

.MARINE...Seas remain hazardous and are expected to remain
hazardous through Tuesday. Wave heights will be up to 7 feet
today, mainly for the Atlantic waters and local passages,
elsewhere, seas will be up to 6 feet. There is a high risk of rip
currents for the north facing beaches of Puerto Rico, moderate
risk for most of the remaining coastlines of PR and the USVI. A
strong northerly swell could invade the local waters this coming
weekend.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 74 84 75 84 / 30 30 50 50
STT 75 84 74 84 / 30 30 40 40

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
436 AM AST Tue Jan 23 2018

.SYNOPSIS...Surface high pressure across the west and central Atlantic
will continue to spread eastward and strengthen over the next few
days. This will maintain moderate to fairly strong east to
northeast trade winds across the local area, with breezy
conditions expected by the end of the week and into the weekend.
Upper ridge will continue over the local islands for the next few
days with an amplifying polar trough still forecast to move
eastward across the Atlantic and slightly erode the upper ridge by
the weekend. A cold front and associated boundary is forecast to
stall and remain north of the local islands over the weekend and
into early next week.

&&

.SHORT TERM...Terminal Doppler Radar indicated only few showers mostly
across the Atlantic waters overnight. Not precipitation was observed
elsewhere across the region overnight and so far this morning. Easterly
trades will continue across the region as a weak high pressure system
remains across the Atlantic, just to the north of the region. This
weak high pressure is expected to be absorbed by another high pressure
across the northwest Atlantic, maintaining an east to east northeast
low level wind flow through Thursday. Small patches of low level moisture
embedded in the trades will move across the local islands from time
to time during the next couple of days producing brief passing showers
across the U.S. Virgin Islands and eastern Puerto Rico from time to
time, especially overnight and early in the mornings for the next couple
of days. During the afternoons, some cloudiness with showers are expected
to develop across the interior and west sections of Puerto Rico.

A cold front is expected to move into the western Atlantic tonight.
A strong surface high pressure behind the cold front will push the
frontal boundary southeastward across the Atlantic waters during
the next couple of days. By Thursday it is forecast to be about
400 miles north northwest of Puerto Rico. By Thursday the low
level wind flow will begin to turn northeast bringing cooler and
slightly drier airmass across the region.

.LONG TERM...Friday through Wednesday of next week. The upper level
high pressure ridge will hold across the region through Friday. However
expect the prevailing east to northeast winds to continue to transport
sufficient shallow moisture across the region to support passing
late evening and early morning showers, followed by the development
of isolated to scattered afternoon convection. Saturday through Sunday,
a polar trough is forecast to amplify and spread eastward across the
west and central Atlantic causing a slight erosion of the upper level
ridge. This will provide better support for afternoon convection across
portions of the islands. By Monday through Wednesday, the mid to upper
level ridge will reestablish over the region and again limit shower
development.

In the low levels, the a cold front is forecast to move across the
west and central Atlantic and stall well north of the local area
by the weekend. However, model guidance suggests a gradual increase
in the trade winds by late Friday and into the weekend with conditions
more favorable for moisture convergence across the islands. As a result,
cooler temperatures but more frequent shower activity is expected due
to the increasing northeast winds and frontal boundary moisture which
will sinks southwards and be transported across the region from time
to time. Gradually improving weather conditions are forecast Monday
through Wednesday with a return of more typical passing trade wind
showers and isolated to scattered afternoon showers mainly over the
west and interior sections of Puerto Rico.

&&

.AVIATION...Mainly VFR conditions are expected across the local
flying area through the forecast period. However, -SHRA on trades
moving across the Leeward islands could move briefly across the USVI
and eastern Puerto Rico terminals this morning.
Thereafter, SHRA will begin to affect mostly TJMZ between 23/18Z and
23/21Z. Latest 23/00z TJSJ upper air sounding indicated ENE winds at
11-24 kt from SFC to FL100.

&&

.MARINE...The northerly swell has subsided across the regional
waters and seas no longer meet small craft advisory criteria. However,
small crafts should continue to exercise caution across both Atlantic
and Caribbean waters and passages due to seas up to 6 feet and/or winds
up to 20 kt. High rip current risk will continue on Tuesday mainly
for the northwestern coast of Puerto Rico. Moderate risk continues
across the rest of the coastal areas of the islands.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 85 75 84 74 / 40 50 50 30
STT 83 75 84 74 / 40 50 50 20

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
538 PM AST Tue Jan 23 2018

SYNOPSIS...Surface high pressure will continue to build across the
eastern Atlantic while another strong surface high enters the
western Atlantic on Friday. A cold front is forecast to move north
of the region during the weekend. This will result in breezy
conditions. Upper ridge will continue over the local islands
through the end of the work week. A polar trough is expected to
move later during the weekend.

&&

.SHORT TERM...Today through Friday...A surge in low level moisture
resulted today in afternoon shower development over the western
interior sections of Puerto Rico. As well as a few showers
developing off streamers across the islands and the eastern
interior mountains. However, no significant rainfall accumulations
were observed. Although the upper ridge will promote the trade
wind cap and drier air during the next few days, enough low level
moisture will continue to aid in the development of diurnally
induced afternoon showers over the western portions of PR and
streamers across the USVI and the eastern mountains of PR.

.LONG TERM...Friday through Wednesday of next week. The upper level
high pressure ridge will hold across the region through Friday. However
expect the prevailing east to northeast winds to continue to transport
sufficient shallow moisture across the region to support passing
late evening and early morning showers, followed by the development
of isolated to scattered afternoon convection. Saturday through Sunday,
a polar trough is forecast to amplify and spread eastward across the
west and central Atlantic causing a slight erosion of the upper level
ridge. This will provide better support for afternoon convection across
portions of the islands. By Monday through Wednesday, the mid to upper
level ridge will reestablish over the region and again limit shower
development.

In the low levels, the a cold front is forecast to move across the
west and central Atlantic and stall well north of the local area
by the weekend. However, model guidance suggests a gradual increase
in the trade winds by late Friday and into the weekend with conditions
more favorable for moisture convergence across the islands. As a result,
cooler temperatures but more frequent shower activity is expected due
to the increasing northeast winds and frontal boundary moisture which
will sinks southwards and be transported across the region from time
to time. Gradually improving weather conditions are forecast Monday
through Wednesday with a return of more typical passing trade wind
showers and isolated to scattered afternoon showers mainly over the
west and interior sections of Puerto Rico.


&&

.AVIATION...A patch of clouds and showers will bring periods of SCT-
BKN ceiling across TJSJ/TIST/TISX through 23/23z. Tempo for
TJMZ/TJSJ/TIST/TNCM were included for SHRA and BKN ceilings at FL020-
FL030 btwn 23/18z-20z. Elsewhere VCSH expected. Thereafter, passing
SHRA will begin to affect the coastal TAFs JSJ/IST/ISX/NCM/KPK.
ENE winds at 10-15 kts with higher gusts up to 25 kt til 23/22z,
bcmg calm to light and variable overnight.


&&

.MARINE...Small crafts should continue to exercise caution across
the Atlantic waters and passages due to seas up to 6 feet.
Elsewhere seas will range between 3-5 feet. East winds will
continue between 5-15 tonight into Wednesday. Marine conditions
will quickly deteriorate during the weekend as a long period
northerly swell and wind driven seas will result in hazardous
confused seas. Small craft advisories will be required across most
of the regional waters. Also, this will result in large breaking
waves and rough surf conditions with life threatening rip
currents across all local islands.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 85 75 84 74 / 30 30 30 10
STT 83 75 84 74 / 40 50 50 20

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
350 AM AST Wed Jan 24 2018

.SYNOPSIS...Surface high pressure across the central Atlantic
will drift eastward while another strong surface high enters the
western Atlantic on Friday. A cold front is forecast to move north
of the region during the upcoming weekend. This will result in
breezy conditions across the region. Upper ridge is expected to
hold over the region through early in the weekend.

&&

.SHORT TERM...Today through Friday...
Trade wind moisture transport will continue across the region with
occasional cloudiness and brief showers expected to continue into
early morning hours. Rainfall will be mostly light to moderate but
isolated areas along the east coastal sections of PR may experience
quick bursts of locally heavy rains in isolated spots. Increasing
shallow moisture advection today through Thursday will support
isolated to scattered showers development mainly across the interior
and west sections of PR during the afternoon hours. The shower
activity however is expected to quickly stream westwards in the
prevailing moderate trade winds. This will result in minimal
rainfall accumulations. On Friday, lesser moisture transport as
upper ridge slightly erodes supporting somewhat drier conditions
with mostly fair weather and breezy conditions, except for locally
induced afternoon showers over the west and southwest sections of
PR, under a prevailing northeast wind flow.

.LONG TERM...Saturday through Thursday of next week...
The upper level ridge is expected to erode rapidly Saturday
through Sunday, as a polar trough amplify and spread eastward
across the west and central Atlantic. This will provide better
support for shower activity across the U.S. Virgin Islands,
Vieques, Culebra as well as across the eastern half of Puerto
Rico during the nights and mornings hours followed by more afternoon
convection across portions of the interior and western sections
of Puerto Rico.

A strong surface high pressure is forecast to move across the
west and central Atlantic behind the cold front Saturday and
Sunday. This feature will remain north of the area, producing
breezy east to east-northeast wind flow across the region during
the weekend and until early next week. As a result, cooler
temperatures but more frequent passing shower activity is expected
due to the increasing northeast winds and frontal boundary
moisture which will sinks southwards and be transported across the
region from time to time. Gradually improving weather conditions
are forecast Tuesday through Wednesday with a return of more
typical passing trade wind showers and isolated to scattered
afternoon showers mainly over the west and interior sections of
Puerto Rico.

&&

.AVIATION...SCT-BKN cld lyrs nr FL022...FL040...FL080 with SHRA
across the regional waters and en route btw islands as well as VCTY
TJSJ/TIST/TISX through 24/12z. Fm 24/17Z-24/22Z...VCSH at
TJBQ/TJMZ/TJSJ/TJNR with brief MVFR conds in passing SHRA.
. Sfc wnds calm to lgt/vrb til 24/14z bcmg fm ENE at 10-15 kts with
higher gusts up to 22 kt til 24/22z.

&&

.MARINE...Small craft are urged to exercise caution as seas will
be up to 6 feet. There is a moderate risk of rip currents across
most of the local beaches. Local seas will remain choppy and up
to 6 feet for the next couple of days. A north to northeasterly
swell will invade the local waters late on Friday, which will
likely cause a significant increase in wave heights and hazardous
seas through the weekend. Stay tuned.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 86 76 83 73 / 40 20 20 30
STT 84 74 84 73 / 50 30 30 30

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
451 PM AST Wed Jan 24 2018

.SYNOPSIS...Surface high pressure will continue to move into the
eastern Atlantic while another strong surface high enters the
western Atlantic by Friday. This will result in breezy conditions
across the region. A mid to upper level ridge will continue over
the local islands through the end of the week. A polar trough and
associated front are expected to remain north of the region later
during the weekend.

&&

.SHORT TERM...Today through Friday...Another surge of low level
moisture resulted today in afternoon shower development mainly
over the southwestern sections of Puerto Rico and in isolated
areas of north central PR. Passing trade wind showers moved at
times across the USVI and streamers developed over St. Thomas and
reached portions of Culebra during the mid afternoon hours.
However, rainfall amounts were around a quarter of an inch with
the heaviest showers.Ridge pattern aloft will promote the trade
wind cap and drier air during the next few days. However, shallow
low level moisture will continue to aid in the development of
diurnally induced afternoon showers over the western portions of
PR and light streamers across the USVI and the eastern mountains
of PR.

.LONG TERM...Saturday through Thursday...From previous
discussion...

The upper level ridge is expected to erode rapidly Saturday
through Sunday, as a polar trough amplify and spread eastward
across the west and central Atlantic. This will provide better
support for shower activity across the U.S. Virgin Islands,
Vieques, Culebra as well as across the eastern half of Puerto Rico
during the nights and mornings hours followed by more afternoon
convection across portions of the interior and western sections of
Puerto Rico.

A strong surface high pressure is forecast to move across the
west and central Atlantic behind the cold front Saturday and
Sunday. This feature will remain north of the area, producing
breezy east to east-northeast wind flow across the region during
the weekend and until early next week. As a result, cooler
temperatures but more frequent passing shower activity is expected
due to the increasing northeast winds and frontal boundary
moisture which will sinks southwards and be transported across the
region from time to time. Gradually improving weather conditions
are forecast Tuesday through Wednesday with a return of more
typical passing trade wind showers and isolated to scattered
afternoon showers mainly over the west and interior sections of
Puerto Rico.


&&

.AVIATION...The Terminal Radar detected shower activity across the
interior and western sections of PR as well as downwind from the
USVI. Occasional SHRA/-SHRA and SCT-BKN ceilings at FL022-FL060
expected at JMZ/JSJ/IST through at least 24/23z. Elsewhere VCSH.
TEMPO groups were included for TNCM/TKPK for brief BKN ceilings at
FL018. Sfc wnds fm ENE at 10-15 kts with higher gusts especially
in/near SHRA, bcmg calm to light and vrb aft 24/23z.


&&

.MARINE...Small crafts should continue to exercise caution across
both Atlantic and Caribbean waters and passages due to seas up to
6 feet and/or east winds up to 20 knots. Elsewhere seas will
range between 3-5 feet. Marine conditions will quickly deteriorate
during the weekend as a long period northerly swell and wind
driven seas result in hazardous confused seas. Small craft
advisories will be required across most of the regional waters.

Also, this will result in large breaking waves and rough surf
conditions with life threatening rip currents across all local
islands. This breaking wave action will also cause beach erosion
mainly across the north facing beaches of the islands.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 76 83 73 83 / 20 20 30 30
STT 74 84 73 85 / 40 40 30 30

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
406 AM AST Thu Jan 25 2018

.SYNOPSIS...Surface high pressure across the central Atlantic
will drift eastward while another strong surface high enters the
western Atlantic Friday and Saturday. This will result in a breezy
conditions across the region. An upper level ridge will continue
over the local islands through the rest of the work week. A polar
trough and associated front are expected to remain across the
Atlantic waters north of the region during the weekend.

&&

.SHORT TERM...Today through Saturday...
Surge of low level trade wind moisture with embedded showers will
continue to move across the region this morning and during the rest
of the day. This will result in periods of mostly light to moderate
morning showers of short duration. While an overall fair weather
skies expected across much of the region during the rest of the day,
local and diurnal effects will give way to afternoon showers mainly
over the central and west to southwest sections of Puerto Rico.
Elsewhere and around the U.S. Virgin Islands, isolated streamer like
showers will remain possible, but the activity will be mainly on the
downwind side of the islands.

The dominant mid to upper level ridge and strengthening surface high
pressure ridge across the west and central Atlantic will continue to
promote the cool advective moisture pattern and overall stable
weather conditions during the next few days. However, the shallow
low level moisture transport and moderate east to northeast trade
winds, will aid in the development of afternoon showers. This will
be mainly over parts of the interior and west to southwest sections
of Puerto Rico as well as around the San Juan Metro and across the
USVI, where brief streamer like convection will remain possible. By
Saturday...Increasing moisture pooling and low level convergence, as
well as strengthening of the northeasterly trade winds is forecast as
the surface high builds north of the region and tightens the local
pressure gradient. Cool near seasonal temperatures and breezy
conditions can therefore be expected.

.LONG TERM...Sunday through Friday...
As the upper ridge erodes, a polar trough will amplify eastward
across the west and central Atlantic Sunday and early next week.
This will provide better support for shower activity across the
local islands and surrounding waters. On Sunday and Monday,
Showers will be more frequent across Vieques, Culebra as well as
across eastern Puerto Rico during the nights and mornings hours
followed by afternoon convection across portions of the interior
and western sections of Puerto Rico.

A strong surface high pressure is expected to remain across the
Central Atlantic until at least Monday. This feature will continue
to produce a breezy east to east-northeast wind flow across the
region. As a result, cooler temperatures but more frequent
passing shower activity is expected due to the increasing
northeast winds and frontal boundary moisture which will sinks
southwards and be transported across the region from time to time.
Gradually improving weather conditions are forecast Tuesday
through Wednesday with a return of more typical passing trade wind
showers and isolated to scattered afternoon showers mainly over
the west and interior sections of Puerto Rico.

&&

.AVIATION...VFR at all terminals durg prd. However, SCT-BKN lyrs nr
FL022...FL040...FL090 ovr local flying area and en route between
islands. dominant E-NE low lvl winds will transport low to mid
level clouds with embedded showers across the region til 25/14z..Mtn
top obscr ovr E PR due to passing SHRA and low clds. Elsewhere VCSH.
Sfc wnds LGT/VRB...BCMG fm ENE at 10-15 kts with higher gusts
especially in/near SHRA, bcmg calm to light and vrb aft 25/23z.

&&

.MARINE...Small crafts should continue to exercise caution across
both Atlantic and Caribbean waters and passages due to seas up to
6 feet and/or east winds up to 20 knots. Elsewhere seas will
range between 3-5 feet. Marine conditions will quickly deteriorate
Friday night and during the weekend as a long period northerly
swell and wind driven seas result in hazardous confused seas.
Small craft advisories will be required across most of the
regional waters. Large breaking waves and rough surf conditions
with life threatening rip currents are possible across all local
islands. The breaking wave action will also cause beach erosion
mainly across the north facing beaches of the islands.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 83 73 81 75 / 30 30 30 40
STT 83 73 84 74 / 40 30 30 40

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
542 PM AST Thu Jan 25 2018

.SYNOPSIS...A strong surface high pressure will enter the
northwestern Atlantic by Friday and move into the central Atlantic
through Monday. A prefrontal shearline is forecast to move near
the region by late Friday and persist through the weekend. These
two features will result in breezy conditions and increase shower
activity across the islands. Upper level ridge will continue to
erode during the next couple of days. Fair weather conditions are
expected by midweek next week.

&&

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

Fair weather conditions were observed today with brief/short lived
showers during the afternoon in isolated areas of the interior and
southwestern PR. Passing trade wind showers were noted across
portions of northern PR and the rest of the islands through the
day. For tonight, a somewhat drier air mass is expected to move
over the islands and limit the frequency of showers as previous
days. However, conditions change later on Friday and Saturday as a
cool advective pattern unfolds just north of the islands as a
prefrontal shearline and strong east to northeast trades push
showers over much of the northern half of PR and the eastern areas
including Culebra, Vieques and the U.S. Virgin Islands.

.LONG TERM...Sunday through Friday...From previous discussion...
As the upper ridge erodes, a polar trough will amplify eastward
across the west and central Atlantic Sunday and early next week.
This will provide better support for shower activity across the
local islands and surrounding waters. On Sunday and Monday,
Showers will be more frequent across Vieques, Culebra as well as
across eastern Puerto Rico during the nights and mornings hours
followed by afternoon convection across portions of the interior
and western sections of Puerto Rico.

A strong surface high pressure is expected to remain across the
Central Atlantic until at least Monday. This feature will continue
to produce a breezy east to east-northeast wind flow across the
region. As a result, cooler temperatures but more frequent
passing shower activity is expected due to the increasing
northeast winds and frontal boundary moisture which will sinks
southwards and be transported across the region from time to time.
Gradually improving weather conditions are forecast Tuesday
through Wednesday with a return of more typical passing trade wind
showers and isolated to scattered afternoon showers mainly over
the west and interior sections of Puerto Rico.


&&

.AVIATION...SHRA/-SHRA are expected to continue at times in/near
TJSJ/TIST/TJPS/TISX/TNCM/TKPK with SCT-BKN lyrs btwn FL020-FL090 ovr
local flying area and en route between islands. SHRA will develop
over TJMZ btwn 25/18z-23z. A brief pause in SHRA expected btwn
26/00z-26/10z. SHRA are expected to affect TJSJ/TIST/TJBQ aft
26/12z. The winds will continue from the E-NE at 10 to 18 knots with
higher gusts in/near SHRA, bcmg calm to light and vrb aft 25/23z,
increasing one again aft 26/13z.


&&

.MARINE...Small crafts should continue to exercise caution across
both Atlantic and Caribbean waters and passages due to seas up to
6 feet and/or east winds up to 20 knots. Elsewhere seas will
range between 3-5 feet through early Friday morning. Marine
conditions will quickly deteriorate by Friday afternoon and
persist through early next week as a large northerly swell and
wind driven seas result in hazardous confused seas across all
local waters. Small craft advisories are in effect starting on
Friday across the Atlantic waters and the Mona Passage. Seas are
currently forecast to build up to 12 feet across the Atlantic
waters and portions of the local passages. Northeast winds up to
25 knots with higher gusts are forecast through the weekend.

Also, large breaking waves and rough surf conditions with life
threatening rip currents are expected across all local islands
through the weekend as well as beach erosion and possible coastal
flooding by late Saturday into Sunday. Residents and visitors are
urged to avoid/exercise caution if going to the beaches of all
the local islands. Additional watches and advisories could be
issued on Friday for the northwest to northeast coastal areas of
the islands.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 73 81 75 82 / 40 60 40 40
STT 73 84 74 85 / 40 50 40 40

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
455 AM AST Fri Jan 26 2018

.SYNOPSIS...A prefrontal shearline is forecast to move near the
region today and persist through early the upcoming weekend. East
northeast winds will continue to bring fragments of low level
moisture across the local islands during the next few days.
Therefore, breezy and showery conditions to continue today and
into the upcoming weekend. Marine conditions are expected to
deteriorate this afternoon and tonight.

&&

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

The dominant east northeast wind flow will bring fragments of low
to mid level trade wind moisture across the region today. Moisture
should however be capped below 700 millibars due to strong inversion
aloft. Periods of mostly light to moderate morning showers of
short duration will be likely during the morning and early afternoon
mainly along the northern half of Puerto Rico and the adjacent
islands. Increasing cloudiness and shower activity expected during
the afternoon across the central interior and southwest section
of PR. Elsewhere and around the U.S. Virgin Islands, isolated to
scattered streamer like showers will be possible with the activity
mainly on the downwind side of the islands.

The dominant mid to upper level ridge and strengthening surface high
pressure ridge across the west and central Atlantic maintain the
cool advective moisture pattern and overall stable weather conditions
during the next few days. However, the shallow low level moisture
transport and moderate east to northeast trade winds, will aid in
the development of afternoon showers. This will be mainly over
parts of the interior and west to southwest sections of Puerto
Rico as well as around the San Juan Metro and across the USVI,
where brief streamer like convection will remain possible. By
Saturday...Increasing moisture pooling and low level convergence,
as well as strengthening of the northeasterly trade winds is
forecast as the surface high builds north of the region and
tightens the local pressure gradient. Cool near seasonal
temperatures and breezy conditions can therefore be expected.

.LONG TERM...Monday through Saturday

A ridge pattern aloft will hold much of the upcoming week as well
as the following week. At lower levels, a high pressure across
the central Atlantic will promote moderate to strong east
northeast winds Monday through early Tuesday. However by mid week,
the surface high is expected to erode as a frontal boundary moves
over the western Atlantic and closer to the local area. A
seasonal weather pattern is expected to prevail through the
forecast period with trade wind showers at times particularly on
Monday and early Friday. The driest day at this time could be
Wednesday.

&&

.AVIATION...SHRA/-SHRA are expected to continue at times in/near
TJSJ/TIST/TJPS/TISX/TNCM/TKPK with SCT-BKN lyrs btwn FL020-FL090 ovr
local flying area and en route between islands. SHRA will develop
over TJMZ btwn 25/18z-23z. A brief pause in SHRA expected btwn
26/00z-26/10z. SHRA are expected to affect TJSJ/TIST/TJBQ aft
26/12z. The winds will continue from the E-NE at 10 to 18 knots with
higher gusts in/near SHRA, bcmg calm to light and vrb, increasing
to 15-20 kts aft 26/14z.

&&

.MARINE...Deteriorating conditions still expected by this afternoon
and continuing trough the weekend as the combination of a northerly
swell and increasing wind driven seas. Small craft advisories
will be in effect by 2 PM AST across the Atlantic waters and the
Mona Passage, then spread into the anegada passage later this
afternoon. Seas are forecast to build up to 12 feet across the
Atlantic waters and portions of the local passages. Strong
northeast winds up to as much as 25 knots with higher gusts are
also forecast through the weekend. A high risk of rip currents
expected across most of the local beaches tonight.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 80 73 79 76 / 60 40 40 40
STT 84 73 84 74 / 50 40 40 40

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
412 PM AST Fri Jan 26 2018

.SYNOPSIS...Shearline will continue to dig southeastward towards
the local area tonight into Saturday. Strong surface high pressure
will build behind the shearline, producing breeze to windy
conditions across the local area through at least Monday.

&&

.SHORT TERM...Variably cloudy skies prevailed across Puerto Rico
and the U.S. Virgin Islands this afternoon. Areas of cloudiness
with showers embedded in the trade winds affected the local
islands from time to time. Rainfall accumulation were less than an
inch. This weather pattern will continue through tonight. A
shearline is expected to move across Puerto Rico Saturday and
Sunday, bringing with it an increase in cloudiness, with scattered
to numerous showers both days. Breeze to windy conditions are
expected as a strong high pressure system builds behind the
shearline.

.LONG TERM...(from previous discussion) Monday through Saturday

A ridge pattern aloft will hold much of the upcoming week as well
as the following week. At lower levels, a high pressure across
the central Atlantic will promote moderate to strong east
northeast winds Monday through early Tuesday. However by mid week,
the surface high is expected to erode as a frontal boundary moves
over the western Atlantic and closer to the local area. A
seasonal weather pattern is expected to prevail through the
forecast period with trade wind showers at times particularly on
Monday and early Friday. The driest day at this time could be
Wednesday.

&&

.AVIATION...SHRA/-SHRA are expected to continue at TJSJ/TIST/TJPS/TISX/TJBQ
and TNCM/TKPK with SCT-BKN lyrs btwn FL020-FL090 ovr local flying
area and en route between islands. SHRA are fcst to develop over
TJMZ btwn 26/18z-23z. The winds will continue from the E-NE at 15
to 25 knots with higher gusts in/near SHRA. Breezy to windy
conditions are forecast to persist through the weekend.

&&

.MARINE...Small craft advisories are in effect across all coastal
waters except across the nearshore waters of southwestern Puerto
Rico. Building seas of 5 to 7 feet and winds up to 25 to 30 knots
are expected. Fresh to strong trades in combination with a large
northerly swell will generate dangerous confuse seas through early
next week. As a result large breaking waves will produce life
threatening rip currents, coastal erosion and coastal flooding
into the upcoming work-week.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 73 79 76 82 / 60 50 40 40
STT 73 84 74 84 / 60 50 40 40

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
607 AM AST Sat Jan 27 2018

.SYNOPSIS...Breezy to windy and showery conditions will continue
to prevail throughout the day. Hazardous seas are expected across
all local waters. Although winds are expected to diminish Monday
and into Tuesday, Hazardous seas will continue to prevail much of
the upcoming weekend.

&&

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

Frontal boundary to our north is dissipating and a strong surface
high pressure across the western atlantic will tighten the local
pressure gradient today into sunday. this will cause strong winds
over the local area. the winds will be strong enough to warrant a
wind advisory across the local islands and a gale warning for the
local offshore atlantic waters due to the frequent wind gusts
expected, with small craft advisories across the rest of the local
waters. on top of the strong winds, there is also sufficient
moisture to have scattered to locally numerous showers moving in
from the northeast. some of these showers will be moderate to
locally heavy. even though the showers are expected to be brief,
they are also expected to be persistent, meaning that off and on
showers are expected through the day, particularly across the
usvi, and the north and eastern sections of puerto rico. a similar
weather pattern is expected for sunday but the local winds are
expected to gradually decrease and become more easterly. also for
monday, easterly winds expected, not as strong as today or sunday
with brief showers mainly affecting the eastern sections of pr as
well as the usvi. for the next few days, the daytime maximum
temperatures should be in the low to mid 80s across the lower
elevations of pr and the usvi, while the higher elevations of pr
should observe daytime maximum temperatures in the 70s. overnight
minimum temperatures in the low to mid 70s across the usvi and
lower elevations of pr and in the 60s across the higher elevations
of PR.

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

A ridge pattern aloft will hold much of the upcoming week as well
as the following week. At lower levels, a high pressure across
the central Atlantic will promote moderate to strong east
northeast winds Monday through early Tuesday. However by mid week,
the surface high is expected to erode as a frontal boundary moves
over the western Atlantic and closer to the local area. A
seasonal weather pattern is expected to prevail through the
forecast period with trade wind showers at times particularly
by the end of the forecast period.

&&

.AVIATION...SHRA will be observed today across the local area,
mostly affecting TIST, TJSJ, and TJBQ. the shra are moving
quickly so the mvfr conds that they may cause should be brief.
winds will be stronger than normal for the next 24 hours. the
winds in the morning will be generally around 15kt, gusting to
about 25 knots from the ene, but will increase even more after
27/16z with winds around 20kt and gusting to about 30kt in most of
the local terminals except maybe TJPS and TJMZ.

&&

.MARINE...A northerly swell and wind driven seas will result in
hazardous seas across the regional waters through early next week.
Northeast winds at around 30 knots with frequent gusts greater
than 34 knots are expected across the northern most offshore
Atlantic waters. Therefore a Gale Warning will be in effect this
afternoon across these waters.

Seas will continue to build across the local waters with seas 12
to 14 feet and breaking waves around 15 feet and increasing by
tonight. As marine conditions continue to deteriorate, the risk of
flooding of low areas along the Atlantic shoreline will continue
to increase.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 81 74 81 74 / 50 60 60 40
STT 85 74 84 74 / 50 30 40 50

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
437 PM AST Sat Jan 27 2018

.SYNOPSIS...Breezy to windy conditions will continue to prevail
through Sunday. A shearline will continue to affect the region
with cloudiness and showers through early Monday. Hazardous seas
are expected across all local waters. Although winds are expected
to diminish Monday and into Tuesday, Hazardous seas will continue
to prevail much of the upcoming weekend.

&&

.SHORT TERM...Tonight through Monday...
Fresh to strong trade winds have resulted as a 1040 mb high pressure
moved off the eastern coast of the U.S. late Friday. The high
pressure will slowly decay as it crowds a developing low between 40
and 50 west longitude Sunday and Monday. The gradient across the
local area however will remain strong until Monday when it will
relax somewhat. There is a cold front north of the area with a band
of moisture at low levels around 21-23 north that is spreading moist
flow across the area. This will continue and the latest 850 mb GFS
suggests that moisture will actually increase during the next 24 to
48 hours. Winds ahead of the front are also being augmented by the
presence of the front. This will sink across Puerto Rico and the
U.S. Virgin Islands on Monday and be south of Puerto Rico, but not
necessarily Saint Croix. Winds will then begin to weaken but will
still be significant.

.LONG TERM...(from previous discussion)Tuesday through Sunday...

A ridge pattern aloft will hold much of the upcoming week as well
as the following week. At lower levels, a high pressure across
the central Atlantic will promote moderate to strong east
northeast winds Monday through early Tuesday. However by mid week,
the surface high is expected to erode as a frontal boundary moves
over the western Atlantic and closer to the local area. A
seasonal weather pattern is expected to prevail through the
forecast period with trade wind showers at times particularly
by the end of the forecast period.

&&

.AVIATION...SHRA will continue--mainly across the north half of PR
and the USVI. SHRA will be fast moving and any MVFR they cause will
be brief. Mtn obscurations should be expected. Coastal stations will
see gusts from 25 to 35 kt. TNCM has already reported gust to 34 kt
at 27/14Z. These winds will continue with only temporary abatement
thru 28/22Z. Maximum winds WSW 45-55 kt btwn FL370-440.

&&

.MARINE...No major changes in marine conditions. Extremely
hazardous marine conditions will continue to prevail through at
least Monday. Building seas between 10 to 12 feet and winds up to
30 knots are expected.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 74 81 74 82 / 70 70 80 80
STT 74 84 74 83 / 50 50 60 60

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
515 AM AST Sun Jan 28 2018

.SYNOPSIS...Breezy to windy and showery conditions will continue
to prevail throughout the day. Hazardous seas are expected across
all local waters. Although winds are expected to diminish Monday
and into Tuesday, Hazardous seas will continue to prevail much of
the week. A drier air mass is expected to encompass the forecast
area by mid week.

&&

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

A strong surface high pressure across the western Atlantic will
continue to cause windy conditions over the local area today.
However, the winds will be gradually diminishing, but they will
remain strong enough for the Wind Advisory over the local islands
and the Gale Warning over the offshore Atlantic waters to be
extended until noon today.

On top of the strong winds, there is still sufficient moisture to
have numerous showers moving in from the northeast. Some of these
showers will be moderate to locally heavy. Even though the showers
are expected to be brief, they are also expected to be frequent,
meaning that off and on showers are expected through the day and
also tonight, particularly across the usvi, and the north and
eastern sections of Puerto Rico. For this reason, the POPs for
chance of precipitation is relatively high but the rainfall amount
forecast is generally a quarter of an inch of rain or less. Not much
will change in the overall pattern in the short term, so similar
weather conditions are expected through Monday with slightly weaker
winds after today. Latest guidance is suggesting that drier air will
make its way to the local islands late on Tuesday, so the shower
activity should be mainly isolated to scattered. For the next few
days, the daytime maximum temperatures should be in the low to mid
80s across the lower elevations of pr and the usvi, while the higher
elevations of pr should observe daytime maximum temperatures in the
70s. Overnight minimum temperatures in the low to mid 70s across the
usvi and lower elevations of pr and in the 60s across the higher
elevations of pr.

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

A mid level ridge pattern will hold much of the forecast period
with some weakening expected on Thursday as a surface boundary
approaches the local isles from the west. Nevertheless, this
boundary will weaken north of the forecast area without a major
impact across the local area. At lower levels, a high pressure
will build across the north central Atlantic to promote an east
northeast wind flow Thursday through early the upcoming week. The
aforementioned pattern will result in seasonable weather conditions
with trade wind showers at times particularly along the east and
north coastal areas of the local islands.

&&

.AVIATION...Frequent but brief SHRA will be observed today across
the local area, mostly affecting the northern USVI and north and
east PR, which would affect mainly TIST, TJSJ, and TJBQ. The SHRA
are moving quickly So the MVFR conds that they may cause should be
only a few minutes long at a time. Winds will be generally at 15 to
25kt with higher gusts from the east.

&&

.MARINE...Hazardous seas continue to prevail with the nearshore
buoy reporting 12 feet at 11 seconds. This wave action will
continue to yield breaking waves at around 16 feet. Seas are
expected to subside somewhat tonight and tomorrow, dropping below
10 feet by Tuesday. However, SCA will remain in effect much of the
upcoming work week. Strong trade winds will continue to prevail
today and tomorrow becoming fresh on Tuesday.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 81 75 81 75 / 70 80 80 60
STT 83 73 83 73 / 50 60 60 50

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
351 PM AST Sun Jan 28 2018

.SYNOPSIS...Breezy to windy and showery conditions will continue
to prevail throughout the day. Hazardous seas are expected across
all local waters. Although winds are expected to diminish Monday
and into Tuesday, Hazardous seas will continue to prevail much of
the week. A drier air mass is expected to encompass the forecast
area by mid week as strong upper level ridge builds north of the
area.

&&

.SHORT TERM...Today through Tuesday...A strong surface high pressure
across the western Atlantic will continue to cause windy
conditions over the local area today. However, the winds will be
gradually diminishing, but they will remain strong enough for the
Wind Advisory over the local islands and the Gale Warning over the
offshore Atlantic waters to be extended until noon today.

On top of the strong winds, there is still sufficient moisture to
have numerous showers moving in from the northeast. Some of these
showers will be moderate to locally heavy. Even though the showers
are expected to be brief, they are also expected to be frequent,
meaning that off and on showers are expected through the day and
also tonight, particularly across the usvi, and the north and
eastern sections of Puerto Rico. For this reason, the POPs for
chance of precipitation is relatively high but the rainfall amount
forecast is generally a quarter of an inch of rain or less. Not much
will change in the overall pattern in the short term, so similar
weather conditions are expected through Monday with slightly weaker
winds after today. Latest guidance is suggesting that drier air will
make its way to the local islands late on Tuesday, so the shower
activity should be mainly isolated to scattered. For the next few
days, the daytime maximum temperatures should be in the low to mid
80s across the lower elevations of pr and the usvi, while the higher
elevations of pr should observe daytime maximum temperatures in the
70s. Overnight minimum temperatures in the low to mid 70s across the
usvi and lower elevations of pr and in the 60s across the higher
elevations of PR.

.LONG TERM...Wednesday through Monday...A strong upper level ridge
is forecast to build north of the area. As a result, fair weather
conditions are expected with only light passing showers affecting
the forecast area from time to time. No significant weather events
are forecast to affect the region in this period.

&&

.AVIATION...Frequent but brief SHRA will be observed today across
the local area, mostly affecting the northern USVI and north and
east PR, which would affect mainly TIST, TJSJ, and TJBQ. The SHRA
are moving quickly So the MVFR conds that they may cause should be
only a few minutes long at a time. Winds will be generally at 15 to
25kt with higher gusts from the east.


&&

.MARINE...Local buoy continued showing seas at 12 feet in the
nearshore waters of Puerto Rico. As a result, decided to extend
the coastal flood advisory through monday morning, as breaking
wave of 18 feet could occur along the north coast of Puerto Rico,
Culebra and the northern U.S. Virgin Islands. High surf and small
craft advisories will continue to effect.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 75 81 75 83 / 80 80 60 50
STT 73 83 73 83 / 60 60 50 50

&&

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
503 AM AST Mon Jan 29 2018

.SYNOPSIS...High pressure to the north of the local area will
gradually weaken today and Tuesday, which will cause the local
pressure gradient to relax and the local winds to slowly diminish.
There is also an upper low to the northeast of the local islands
which will remain to our northeast through Thursday before
dissipating. The local islands should remain in the subsident side
of this upper low, so the local showers that are expected should
not have upper level support and the showers that do affect the
local islands should be generally brief as they pass by. Overall
moisture is expected to decrease late on Tuesday and the drier
airmass is expected to remain through the rest of the workweek.

&&

.SHORT TERM...Monday through Wednesday...

Breezy to windy conditions prevailed overnight and early this morning
with frequent passing showers observed across the eastern sections of
the local islands. Temperatures were in the low to mid 70s at lower
elevations and in the 60s at higher elevations.

Although a surface high north of the area is expected to weaken
throughout the day, fresh to strong easterly winds will continue to
prevail. On Tuesday and Wednesday, as the surface high continues to
weaken, a moderate east northeast wind flow is then expected to prevail.
The aforementioned wind flow will continue to bring the remnants of
an old frontal boundary across the forecast area through at least
Tuesday. Therefore, showery conditions will continue to prevail. At
upper levels, a mid level ridge will hold early in the forecast
cycle with a weakening expected on Wednesday as a frontal boundary
approaches from the west. Nevertheless, a fair weather pattern is
expected as a drier air mass encompasses the eastern Caribbean.

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

The latest guidance is suggesting that the overall moisture in
the long term will be below normal, which may cause shower
activity to be limited in coverage and in amounts. A surface high
to the north of the local islands over the western Atlantic, and
another surface high pressure over the central Atlantic will cause
east northeast to northeast winds over the local islands through
late this week into the weekend. The shower activity that is
expected will be mainly brief and in the windward side of the
local islands. Otherwise it looks like several nice days are in
store with the lower moisture over the local area.


&&

.AVIATION...Brief MVFR conditions likely at TIST/TISX/TJSJ/TJBQ
as well as the Leeward terminals in SHRA/-SHRA through the forecast
period. Easterly winds to continue at 20-25 kts, becoming
at around 15 knots overnight.


&&

.MARINE...The local marine and surf zone conditions continue to be
dangerous. We currently have in effect a Small Craft Advisory,
High Surf Advisory, Coastal Flood Advisory, and a high risk of rip
currents. The different advisories expire at different times
depending of the location as the northerly swell becomes more
northeasterly and as winds diminish slightly. Please look at our
local marine products for details on the different areas. Overall,
the local seas are forecast to have wave heights up to 14 feet and
the breaking waves up to 16 feet, especially for the beaches of
northern Puerto Rico. The coastal flood advisory is currently in
effect until 8 AM this morning due to


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 81 74 81 73 / 80 60 50 20
STT 83 73 82 69 / 60 60 50 20

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
407 PM AST Mon Jan 29 2018

.SYNOPSIS...The weak shear line has washed out leaving drier air
in the mid to upper levels of the atmosphere. Resent SAN Juan
Skew-T sounding also shows the drier air in the mid to upper
levels this has limited showers across Puerto Rico and the U.S.
Virgin Islands today. The strong Atlantic high pressure to the
north of the local area will continue to weaken over the next
several days which will cause the pressure gradient over the
region to also decrease thus winds will fall to a more normal
range of 10 to 20 mph. Later this week a surface ridge of high
pressure will move over the area bringing mostly fair weather
conditions for Puerto Rico and the U.S. Virgin Islands.

&&

SHORT TERM...Tonight through Thursday... Showers and gusty winds
continued across the northern U.S. Virgin Islands and the north
two thirds of Puerto Rico today. A local spotter in Hatillo
reported a 40 mph gust, and winds earlier in the morning at San
Juan gusted to 36 mph. It has been cooler along the coast where
San Juan had only 73 degrees for a low. Drier air is slowly
approaching the local area behind the moisture and showers
generated around the shearline that is slowly dragging south
across Puerto Rico and the U.S. Virgin Islands. Although minor
disturbances will distort the moisture field along the shearline,
it should be completely past the local forecast area by Tuesday
night. A passing mid latitude east-moving trough will also finally
allow surface winds to relax by as much as 5 to 10 knots on
Tuesday. A 1031 mb high pressure is expected to move off the south
Carolina coast on Wednesday morning and winds will return to 15
to 20 knots across the island coasts and local waters. This drier
air will be out of the central Atlantic and the GFS is showing
precipitable water values between 1.20 and 0.75 inches between
Tuesday evening and noon Friday. This will bring general clearing,
much less shower activity and with less winds in generally more
pleasant conditions.

Upper levels are somewhat supportive of the drying trend. A ridge
will collapse as it crosses Puerto Rico Tuesday evening, then an
upper level trough will pass north of the area to maintain basically
zonal flow or westerly flow. With dry mid layers the entire period
there will be little above the low level atmosphere to disturb the
drier weather expected.

.LONG TERM...Surface high pressure and an Atlantic ridge will
bridge over the region later this week thus decreasing showers and
low level moisture. Although low level moisture will be limited
over Puerto Rico and the U.S. Virgin Islands isolated showers are
still possible over the island chains due to easterly trade winds
but showers should be brief with light rainfall accumulations.
Otherwise, guidance is hinting at mostly fair weather conditions
for the weekend.


&&

.AVIATION...MVFR will continue to be possible across the Leeward
Islands in SHRA as shearline moisture moves across the area. Expect
clearing around 30/18Z. Some mtn obscurations will be seen across
the hir trrn of PR otherwise VFR is expected to prevail.
Easterly sfc winds cont to prevail from 15 to 20 kt with gusts from
25 to 32 kt. This will abate slowly aft 29/22Z to 10 to 15 kt near
the coasts. Max winds WNW 35-40 kt btwn FL390-460.

&&

.MARINE...The local marine conditions will continue to improve
over the next several days but at this time conditions remain
dangerous across the north Atlantic waters and local water ways. We
currently have in effect a Small Craft Advisory, High Surf
Advisory, and a high risk of rip currents. Be mindful that these
advisories expire depending of the location as the northerly
swell becomes more northeasterly and as winds diminish slightly.
Please look at our local marine products for details on the
different areas. The local seas will have wave heights up to 12
feet and breaking waves ranging from 12 to 16 feet.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 74 81 73 81 / 40 40 20 40
STT 73 82 69 83 / 30 20 20 20

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
437 AM AST Tue Jan 30 2018

.SYNOPSIS...Weakening surface high pressure to the north northeast
of the local area will dissipate by midweek as another surface
high pressure enters the western Atlantic. The local winds will
diminish slightly over the next few days remaining easterly but
shifting to a northeasterly direction starting late on Wednesday.
Drier air is expected to move into the local area late tonight,
remaining over the local area through the rest of the workweek.
Shower activity is expected to be rather limited for the second
part of the week.


&&

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

Mostly cloudy skies prevailed overnight and early this morning
across the forecast area with a few passing showers observed across
eastern Puerto Rico and the US Virgin Islands. Temperatures were in
the low to mid 70s at the lower elevations and in the 60s at the
higher elevations.

A mid level ridge across the western Atlantic will continue to erode
as a broad polar trough moves into the western Atlantic. Although
the ridge pattern will weaken to the north of the forecast area, its
remnants will hold across the local islands. As a result, trade
winds cap is forecast to strengthen through Wed morning. Surface
front associated with the aforementioned trough is expected to move
closer to the forecast area Wed-Thu while it dissipates. Winds are
also expected to increase by Thursday as a surface high builds
across the western and central Atlantic.

Under this evolving pattern, still expect a mainly fair weather
pattern with passing showers embedded in the trades at times.
Pleasant temperatures to continue.

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

A rather uneventful weather pattern is expected in the long range
forecast with mainly zonal flow in the upper levels, east
northeast to easterly wind flow at the surface, and patches of
moisture moving through the local area causing moments of passing
showers that will mostly affect the northern and eastern sections
of Puerto Rico and the USVI. Otherwise mainly fair weather would
be expected with normal maximum and overnight minimum temperatures
for the time of year. The main thing to look for is the marine and
surf zone conditions which could again be hazardous.

&&

.AVIATION...VFR conds are expected to prevail through the
forecast cycle with brief MVFR conds possible at TIST/TISX/TJSJ as
well as the Leeward terminals in -SHRA. Aft 30/17z brief MVFR conds
are also possible in and around TJMZ. Easterly winds to continue at
15 kts, becoming at around 10 knots overnight.


&&

.MARINE...The local marine conditions continue be hazardous. There
are still a few advisories in effect such as the Small Craft
Advisory, High Surf Advisory and a high risk of rip currents. The
local coastal winds are decreasing slowly but the combination of
the northeasterly swell and the winds continue to cause these
hazardous seas locally. Breaking waves of 10ft or higher are
expected through Thursday so the high surf advisory continues in
effect until Thursday afternoon, also the high risk of rip
currents. The small craft advisory due to seas of 7 feet or higher
is currently in effect until Friday, but it is possible to have
7ft seas or higher even past this Friday.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 82 73 82 73 / 30 20 20 20
STT 81 73 81 72 / 30 20 20 20

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
437 AM AST Tue Jan 30 2018

.SYNOPSIS...Weakening surface high pressure to the north northeast
of the local area will dissipate by midweek as another surface
high pressure enters the western Atlantic. The local winds will
diminish slightly over the next few days remaining easterly but
shifting to a northeasterly direction starting late on Wednesday.
Drier air is expected to move into the local area late tonight,
remaining over the local area through the rest of the workweek.
Shower activity is expected to be rather limited for the second
part of the week.


&&

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

Mostly cloudy skies prevailed overnight and early this morning
across the forecast area with a few passing showers observed across
eastern Puerto Rico and the US Virgin Islands. Temperatures were in
the low to mid 70s at the lower elevations and in the 60s at the
higher elevations.

A mid level ridge across the western Atlantic will continue to erode
as a broad polar trough moves into the western Atlantic. Although
the ridge pattern will weaken to the north of the forecast area, its
remnants will hold across the local islands. As a result, trade
winds cap is forecast to strengthen through Wed morning. Surface
front associated with the aforementioned trough is expected to move
closer to the forecast area Wed-Thu while it dissipates. Winds are
also expected to increase by Thursday as a surface high builds
across the western and central Atlantic.

Under this evolving pattern, still expect a mainly fair weather
pattern with passing showers embedded in the trades at times.
Pleasant temperatures to continue.

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

A rather uneventful weather pattern is expected in the long range
forecast with mainly zonal flow in the upper levels, east
northeast to easterly wind flow at the surface, and patches of
moisture moving through the local area causing moments of passing
showers that will mostly affect the northern and eastern sections
of Puerto Rico and the USVI. Otherwise mainly fair weather would
be expected with normal maximum and overnight minimum temperatures
for the time of year. The main thing to look for is the marine and
surf zone conditions which could again be hazardous.

&&

.AVIATION...VFR conds are expected to prevail through the
forecast cycle with brief MVFR conds possible at TIST/TISX/TJSJ as
well as the Leeward terminals in -SHRA. Aft 30/17z brief MVFR conds
are also possible in and around TJMZ. Easterly winds to continue at
15 kts, becoming at around 10 knots overnight.


&&

.MARINE...The local marine conditions continue be hazardous. There
are still a few advisories in effect such as the Small Craft
Advisory, High Surf Advisory and a high risk of rip currents. The
local coastal winds are decreasing slowly but the combination of
the northeasterly swell and the winds continue to cause these
hazardous seas locally. Breaking waves of 10ft or higher are
expected through Thursday so the high surf advisory continues in
effect until Thursday afternoon, also the high risk of rip
currents. The small craft advisory due to seas of 7 feet or higher
is currently in effect until Friday, but it is possible to have
7ft seas or higher even past this Friday.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 82 73 82 73 / 30 20 20 20
STT 81 73 81 72 / 30 20 20 20

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
517 PM AST Wed Jan 31 2018

.SYNOPSIS...Frontal boundary will dissipate north of the region
by late Thursday. Surface high entering the Western Atlantic will
merge with another surface high over the Azores during the
weekend. Moderate to locally fresh east to northeast winds will
return on Thursday and continue through early next week. Fair
weather conditions and seasonable temperatures are expected for
the next several days. Marine conditions will continue to be the
main hazard through the weekend.

&&

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

A few clouds and light showers developed this afternoon over
portions of the southwest quadrant of PR. Light passing showers
were moving from the Atlantic waters into the northern USVI late
this afternoon. Some of this low level clouds and light showers
could move under a northeast steering wind flow over portions of
northeastern PR this evening. However, dry air aloft and high
pressure pattern will keep mostly fair weather conditions during
the next few days. On Friday, a small pulse of low level moisture,
possibly associated with the remnants of the front is expected to
result in a brief increase in trade wind shower activity over
portions of the USVI and eastern PR. Seasonable temperatures are
expected through the rest of the week with highs reaching the mid
80s across coastal areas and lows ranging from the high 50s to low
60s across the higher elevations.

.LONG TERM...Saturday through Wednesday...From previous
discussion...

A typical weather pattern for the time of year is expected for
the long range forecast with mainly zonal flow in the upper
levels through the weekend and then an upper ridge over the local
area early in the upcoming week. East-northeast to easterly wind
flow at the surface, with generally dry air over the local area
but some patches of moisture moving through the local area, which
will cause brief passing showers, affecting the northern and
eastern sections of Puerto Rico, the local waters and the USVI.
After the patches of moisture move away, fair weather would be
expected with normal maximum and overnight minimum temperatures
for the time of year. The main thing to look for is the marine and
surf zone conditions which could continue to be hazardous.


&&

.AVIATION...VFR conds durg entire prd at all terminals. SCT ocnl BKn
cld lyrs nr FL025...FL050...ovr land areas til 31/23z, and en route
btw PR and nrn Leeward islands with FEW passing -SHRA/SHRA.
Prevailing E-NE low level wnd flow BLO FL100...then backing and incr
w/ht ABV. VCSH TJSJ/TIST/TNCM/TKPK FM01/00Z-014Z. No sig operational
AVN wx impacts anticipated durg prd.


&&

.MARINE...Long period northeast swell between 5-7 feet continues
across the regional waters. East to northeast winds between 10-15
knots are expected to increase at 15-20 knots overnight through
Thursday. Another pulse of a northerly swell is expected to reach
the local Atlantic waters and passages on Friday and continue
through the weekend. Therefore, small craft advisories as well as
the high rip current risk were extended through the weekend. High
surf conditions due to breaking waves of 10 feet are expected to
continue across the north coast of PR until Friday and until
Thursday for St. Croix. Regardless, life threatening rip currents
will continue across most of the north and east facing beaches of
all local islands through the weekend.

Refer to latest coastal hazard message product (CFWSJU) for more
information.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 70 83 73 82 / 30 30 30 30
STT 69 83 73 84 / 30 30 30 30

&&

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
445 AM AST Thu Feb 1 2018

.SYNOPSIS... Upper level ridge will continue to dominate the
local region next couple of days. Areas of low level moisture
associated with the remnants of a frontal boundary will move
across the region by the end of the work week, increasing the
chances of showers across the forecast area.

&&

.SHORT TERM...Today through Saturday...
Currently at the surface, a frontal boundary is located just to the
north of Puerto Rico and the U.S. Virgin Islands. Infrared satellite
imagery shows a layer of clouds at low to mid levels approaching the
islands from the east to northeast, with some cirrus also moving
through the area. Although mostly cloudy skies is expected to
prevail across the islands, under a northeasterly wind flow quick
passing showers can not be ruled out across the windward sections of
northern and eastern Puerto Rico and the northern U.S. Virgin
Islands later in the morning hours. Pleasant temperatures are
expected today across the islands. Main short term concern revolves
around the coastal hazards, where hazardous breaking waves will
produce life threatening rip currents from the northwest to
northeast coastline of Puerto Rico and along the U.S. Virgin Islands
over the next several days.

A few shallow clouds with some passing showers could move under a
northeast steering wind flow over portions of the windward sections
of northern and eastern PR, and the U.S. Virgin Islands each day.
However, fair weather conditions will continue as a ridge pattern
holds through the forecast period. On Friday and Saturday, pulses of
low level moisture will result in an increase in trade wind shower
activity over portions of the USVI and eastern PR. The maximum
temperatures are forecast along the coastal areas reaching the mid
80s and the minimum temperatures across the higher elevations
ranging between the high 50s and low 60s.

.LONG TERM...Sunday through Friday...Strong surface high pressure
across the north western Atlantic will move eastward as a low
pressure and associated cold front exit the U.S. east coast by mid
week. This will induce a moderate to fresh trade winds across the
region during the forecast period. These winds will transport
patches of low level moisture to the local area. At this time, no
significant weather events are forecast to affect the region in
the long term.

&&

.AVIATION...No significant SHRA activity is expected at this time.
However, a layer of shallow clouds will create BKN-OVC ceilings btwn
FL030-FL060. VCSH remain possible btwn 01/15z-23z at TJSJ/TIST/TJMZ.
Sfc winds will continue from the E-NE btwn 8 and 12 kts increasing
at 14-18 kt with occasional gusty winds aft 01/13z.

&&

.MARINE...Although local buoys indicated subsiding seas across the
local waters,this will not last too long. Another pulse of a
northerly swell is expected to reach the local Atlantic waters and
passages on Friday and continue through the weekend. Therefore,
small craft advisories as well as the high rip current risk were
extended through the weekend. High surf conditions due to breaking
waves of 10 feet are expected to continue across the north coast
of PR until Friday and until this afternoon for St. Croix.
Regardless, life threatening rip currents will continue across
most of the north and east facing beaches of all local islands
through the weekend.

Refer to latest coastal hazard message product (CFWSJU) for more
information.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 83 73 83 74 / 20 20 40 50
STT 83 72 83 73 / 20 20 40 50

&&