Area Forecast Discussion
Issued by NWS San Juan, PR

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000
FXCA62 TJSJ 240200
AFDSJU

Area Forecast Discussion
National Weather Service San Juan PR
1000 PM AST Wed Jan 23 2019

.UPDATE...
Scattered to numerous showers are moving across the local waters
and moving inland across the northern U.S. Virgin Islands, the
northern, eastern and southern coast of Puerto Rico. Breezy trade
winds will continue across the windward sections. This weather
pattern will continue through the latter part of the work-week,
with the shower activity spreading into into the interior and
western sections during the afternoons. Rainfall accumulations and
the vertical development of these showers will be limited by the
presence of a mid to upper level ridge.

&&

.AVIATION...
Scattered to Numerous SHRA will continue across the local flying
area and some of them will affect the PR/USVI and Leeward Islands
terminals at times. Brief periods of MVFR cannot be ruled out
especially in SHRA/+SHRA. E-NE winds around 10 expected overnight
increasing at 15 to 20 with occasional higher gusts between 20
and 30 knots after 24/13z.

&&

.MARINE...
Hazardous marine conditions continues across most of the local
waters and hazardous coastal conditions will continue along the
north and west facing beaches of Puerto Rico and the U.S. Virgin
Islands. No changes were made to the previous marine discussion.

&&

.PREV DISCUSSION... /issued 428 PM AST Wed Jan 23 2019/

SYNOPSIS...
A surface high pressure moving across the Western Atlantic will
continue to tighten the local pressure gradient promoting a fresh
to strong northeast wind flow. The remnants of a frontal boundary
stalled north of the islands will promote fragments of moisture
approaching the islands at times. Coastal conditions will
deteriorate tonight through the latter part of the work-week.

SHORT TERM...Tonight through Friday...
A strong high pressure ridge north of the eastern Caribbean will
result in a tight pressure gradient across the islands. Breezy
trade winds will bring fragments of moisture with clouds and
showers across the islands tonight through Friday. The remnants of
a frontal boundary will move southward near the region while its
dissipates. Satellite and radar images detected passing showers
across most of the islands. Shower activity is expected to
diminish across the southwest quadrant overnight, while the rest
of the islands will observe quick passing showers at times.

A similar weather pattern will continue through the end of the
work-week, with quick passing showers across the north, east and
south sections, followed by afternoon convection across the
western sections during the afternoon hours. However, winds
and cloud cover should diminish Thursday and Friday. Vertical
development will be limited by the presence of a mid to upper
level ridge.

LONG TERM...Saturday through Thursday

Models continue to show little change in the long term range, and
it still looks like mainly fair weather with brief showers are to
be expected this weekend and early next week. latest guidance
suggest conditions will be drier than normal and any available
moisture will be limited to the lower levels. Winds are expected
to be generally from the east at around 10 to 15 mph, occasionally
to 20 mph in gusts across the coastal areas. A broad mid to upper
level ridge will be established over the region. This will promote
a stable atmosphere, allowing for mainly brief morning and evening
showers while limiting the intensity and coverage of the
afternoon convection.

AVIATION...
Sct SHRA will continue to affect most of the region at
times throughout the forecast period with VCSH expected across most
of the PR/USVI and Leeward Islands terminals. Mainly VFR conditions
are expected, however, brief MVFR conditions cannot be ruled out in
SHRA. E-NE winds between 10 and 20 knots with occasional gusts
between 20 and 30 knots are expected.

MARINE...Marine conditions will continue to deteriorate tonight.
Small craft advisory will be in effect for most of the local
waters due to seas that could reach as much as 12 feet across the
offshore Atlantic waters, and ranging between 6 and 10 feet
elsewhere by tonight. There is a high risk of rip currents for
many of the local beaches and a high surf advisory will go into
effect this evening across the northern beaches of Puerto Rico,
Culebra, and Saint Thomas due to breaking waves of 10 feet or
higher.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU  72  83  73  86 /  60  40  40  30
STT  73  83  73  84 /  50  40  40  30

&&

.SJU WATCHES/WARNINGS/ADVISORIES...
PR...High Rip Current Risk through late Friday night for Culebra-
     North Central-Northeast-Northwest-San Juan and Vicinity.

     High Surf Advisory until 6 PM AST Thursday for Culebra-Mayaguez
     and Vicinity-North Central-Northeast-Northwest-San Juan and
     Vicinity.

     High Rip Current Risk through Thursday afternoon for Southwest-
     Vieques.

     High Rip Current Risk through late Thursday night for Mayaguez
     and Vicinity.

VI...High Rip Current Risk through late Friday night for St Croix-
     St.Thomas...St. John...and Adjacent Islands.

     High Surf Advisory until 6 PM AST Thursday for St.Thomas...St.
     John...and Adjacent Islands.

     Small Craft Advisory until 8 AM AST Saturday for St.Thomas...St.
     John...and Adjacent Islands.

AM...High Rip Current Risk through Thursday afternoon for Coastal
     Waters OF Southwestern Puerto Rico out 10 NM.

     Small Craft Advisory until 2 AM AST Friday for Coastal Waters of
     Southern Puerto Rico out 10 NM.

     Small Craft Advisory until 8 AM AST Saturday for Anegada Passage
     Southward to 17N-Atlantic Waters of Puerto Rico and USVI
     from 10 NM to 19.5N-Caribbean Waters of Puerto Rico from 10
     NM to 17N-Coastal Waters of Northern Puerto Rico out 10 NM-
     Coastal Waters of Northern USVI and Culebra out 10 NM-Mona
     Passage Southward to 17N.

     Small Craft Advisory until 2 AM AST Saturday for Coastal Waters
     of Southern USVI Vieques and Eastern Puerto Rico out 10 NM.

     Small Craft Advisory until 2 PM AST Thursday for Coastal Waters
     OF Southwestern Puerto Rico out 10 NM.

     Small Craft Advisory until 8 AM AST Friday for Coastal Waters OF
     Northwestern Puerto Rico out 10 NM.

&&

$$

SHORT TERM...CAM
LONG TERM....RGH
AVIATION...CAM


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