Area Forecast Discussion
Issued by NWS San Juan, PR

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FXCA62 TJSJ 182035

Area Forecast Discussion
National Weather Service San Juan PR
435 PM AST Mon Feb 18 2019

.SYNOPSIS...Ridge aloft will continue to promote fair weather
conditions across the local islands much of the week. Building
surface high north of the area will bring breezy conditions by


.SHORT TERM...Tonight thru Wednesday...

Short term forecast on track, under mid to upper level ridge, a
generally fair and mainly stable weather pattern will continue to
prevail through the forecast cycle. Surface winds are expected to
become moderate to fresh from the east northeast by midweek as a
surface high pressure builds north of the area. Under this evolving
pattern, shower activity, if any, will be focused across eastern
portions of Puerto Rico as well as the US Virgin Islands as the
trade wind flow moves patches of low level moisture at times. A
few locally induced afternoon showers cant be ruled out across W
PR each day. Breezy.

.LONG TERM...Thu thru Tue /issued 516 AM AST Mon Feb 18 2019/

Fair weather conditions will prevailed through the long term
forecast. A mid-upper level ridge will promote subsidence limiting
convection across the islands. Forecast soundings continues to
suggest the presence of a strong trade wind inversion which is
consistence with drier than normal conditions at mid-to-upper
levels as depicted in the vertical cross-section. However, breezy
trade winds will bring patches of low level moisture with
embedded clouds and showers across the windward sections of Puerto
Rico and the U.S. Virgin Islands each days. A similar weather
pattern will persist throughout the long term forecast.

A migratory high pressure across the Atlantic waters will
strengthen the local pressure gradient increasing the easterly
winds between 15 and 25 knots especially across the local waters
and coastal sections by mid-week into the upcoming weekend.


.AVIATION...Mainly VFR conditions are expected to prevail across all
terminals during the next 24 hours. Streamers will continue to
result in -shra/VCSH between the USVI terminals and eastern PR
through 22z. Iso SHRA could develop in and around TJMZ through 22z.
Low level winds will continue from the east between 15-25 kt.


.MARINE...A surface high pressure building north of the forecast
area will bring hazardous marine conditions tomorrow through much
of the workweek with seas increasing to 7 feet under moderate to
fresh east northeast winds.


SJU  72  84  74  83 /  20  20  20  20
STT  72  84  73  84 /  20  20  20  20


AM...Small Craft Advisory from 2 AM Tuesday to 6 PM AST Friday for
     Caribbean Waters of Puerto Rico from 10 NM to 17N-Mona
     Passage Southward to 17N.



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