Area Forecast Discussion
Issued by NWS San Juan, PR

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FXCA62 TJSJ 162115
AFDSJU

Area Forecast Discussion
National Weather Service San Juan PR
515 PM AST Fri Nov 16 2018

.SYNOPSIS...Low to mid level ridge will continue northeast of the
region through next week. An upper level trough is forecast to
remain over and to the east of the Leeward islands. Moderate to
fresh trade winds will prevail across the region for the next
several days. Patches of low level moisture will move at times
with the trade winds. Diurnally induced showers are expected each
afternoon with a slight chance of thunderstorms over western PR.


&&

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

A wind surge will continue across the forecast area through at
least Saturday morning, but breezy conditions will continue across
the Caribbean waters and the northern coastal waters of PR through
the weekend. Low level moisture embedded on the trade winds will
continue to result in passing showers overnight across the USVI
and the eastern half of PR. Although drier mid to upper level air
will filter at times over the region, enough moisture through
700 mb will be enough to support afternoon convection over western
PR and from streamers across the USVI and smaller islands through
the short term period. On Sunday, models continue to suggest a
drop in overall moisture across the area, with best moisture below
850 mb. This and ridge aloft should inhibit shower coverage as
well the potential for afternoon thunderstorms over western PR.




LONG TERM...Monday through Thursday.../issued 532 AM AST Fri Nov
16 2018/

Mid to upper level ridge will hold most of the next week, under
generally fair weather conditions. The drier and more stable air
mass at mid-levels will reduce the coverage of the showers and
the probability of thunderstorms. However, weak easterly
perturbation embedded in the trade winds will briefly enhance the
diurnal shower activity Monday and Wednesday when these
pertubations are forecast to move across the eastern Caribbean.
The rest of the week expect typical weather conditions with brief
passing showers over eastern Puerto Rico and the U.S. Virgin
Islands during the morning hours, followed by some afternoon
showers over western Puerto Rico. Winds will gradually diminish as
the week progresses due a weakening of the surface high pressure
over the north central Atlantic. All in all, a drying trend and a
decrease in shower activity is forecast next week under the
influence of a mid-upper level ridge.


&&

.AVIATION...SHRA/-TSRA could cause tempo MVFR conds at TISX and
across the PR terminals through 17/00z. Mainly VFR conditions
expected through at least 17/16z. SHRA/TSRA btw 17/16z-22z could
cause tempo MVFR conds once again across the western terminals of
PR. Low level winds will continue E-ESE at 15-20 kts with lighter
land breeze variations overnight across the PR terminals.

&&

.MARINE...Choppy seas will continue through the weekend across the
regional waters. Small craft advisories continue in effect due to
seas up to 7 feet. Breezy trades will continue between 15-20 knots
through the overnight hours across most of the local waters. Moderate
to locally fresh trades will prevail through the weekend, with
higher winds across the coastal waters of the islands and over the
Anegada Passage. High risk of rip currents will continue through
at least Sunday afternoon for the northern beaches of Puerto Rico.
A moderate risk of rip currents will prevail for most of the
northern and eastern beaches of the islands through the weekend.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU  77  87  77  88 /  30  30  20  20
STT  78  86  78  86 /  20  30  30  30

&&

.SJU WATCHES/WARNINGS/ADVISORIES...
PR...High Rip Current Risk through Sunday afternoon for North Central-
     Northeast-Northwest-San Juan and Vicinity-Southeast-Western
     Interior.

VI...High Rip Current Risk through late tonight for St Croix.

AM...Small Craft Advisory until 8 PM AST Saturday for 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-Coastal Waters of Southern USVI
     Vieques and Eastern Puerto Rico out 10 NM-Mona Passage
     Southward to 17N.

     Small Craft Advisory until 8 PM AST Sunday for Atlantic Waters
     of Puerto Rico and USVI from 10 NM to 19.5N.

     Small Craft Advisory until 8 AM AST Sunday for Anegada Passage
     Southward to 17N.

&&

$$

DS


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