Area Forecast Discussion
Issued by NWS San Juan, PR

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FXCA62 TJSJ 230915 CCA

Area Forecast Discussion...CORRECTED
National Weather Service San Juan PR
515 AM AST Fri Jun 23 2017

.SYNOPSIS...Trade wind showers across windward areas during the
morning hours, followed by some shower and thunder development
across west sections of Puerto Rico are expected through the
weekend. The chance for showers and thunderstorms will increase
across the local isles on Monday as a tropical wave moves across
the eastern Caribbean. Locally induced afternoon showers and
thunderstorms are expected Tue followed by limited shower/thunder
activity on Wed. Another tropical wave will move across the
eastern Caribbean on Thursday.


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

Ridge pattern will continue to dominate over the next few days.
Mid-upper level ridge over Florida and Bahamas is keeping the
atmosphere fairly stable across the Northeast Caribbean. The dry
and subsidence air aloft will inhibit the development of
thunderstorms across the local area today. However...low level
moisture will combine with local effects to produce a round of
showers over interior and west portions of Puerto Rico this
afternoon. Brisk easterly winds will continue to push trade wind
showers over the east side of the islands at times...especially
at night and early in the morning.

Patches of low level moisture will advect over the area on Saturday...
keeping the scattered showers in the forecast. However...light to
moderate convection will then cluster over the Northwest PR as
winds veer to the southeast on Saturday. For Sunday...conditions
will remain fairly dry and stable ahead of the next tropical wave
that will encompass the region between Sunday night and Monday

.LONG TERM...Monday through Saturday...

A sharp increase in shower and thunder activity is expected across
the forecast area on Monday as a tropical wave moves across the
eastern Caribbean. This feature is expected to interact with a mid
to upper level trough northeast of the forecast area to result in
enhanced/organized convection across the local isles throughout
the day. Although moisture is expected to decrease as soon as
Tuesday, lingering moisture will interact once again with the
aforementioned trough to result in scattered showers and isolated
thunderstorms across west Puerto Rico Tuesday afternoon. A fair
weather pattern is then expected on Wednesday associated with
subsidence ahead of the next tropical wave which is expected to
reach the area on Thursday. Plenty of moisture will persist across
the forecast area through at least the upcoming weekend to assure
passing showers across windward areas in the morning hours
followed by locally induced afternoon showers and thunderstorms
across the interior and west sections of Puerto Rico.


.AVIATION...VFR conds expected at all TAF sites. SHRA will develop
near TJMZ between 18Z-21Z. East winds of 15-20 kts will prevail
below FL150.


.MARINE...Seas up to 5 feet and winds 15-20 knots are expected to
prevail across the local waters during the next few days. The
next tropical wave passage is expected on Monday, increasing
showers and thunderstorms across the local waters.


SJU  88  77  90  77 /  30  40  40  30
STT  90  78  89  79 /  30  40  40  30




LONG TERM....OM is the U.S. government's official web portal to all federal, state and local government web resources and services.