Flash Flood Watch 7, NWS JSJ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
303 PM AST THU MAY 21 2009

.SYNOPSIS...UPPER LEVEL TROUGHFINESS ACROSS THE SOUTHWESTERN
CARIBBEAN AND A WESTERLY SUBTROPICAL JET FLOW DOMINATING
ALOFT...IS KEEPING THE LOCAL AREA UNDER MOSTLY CLOUDY SKIES DUE TO
THE THUNDERSTORM BLOW-OFF CLOUD MASS ASSOCIATED TO A MID TO UPPER
DISTURBANCE THAT COVERS MUCH OF THE WINDWARD PASSAGE/HAITI/HISPANIOLA.

AT LOW LEVELS...SURFACE TROUGH ACROSS THE NORTHEASTERN CARIBBEAN
WILL MAINTAIN A GENTLE TO MODERATE SOUTHEASTERLY WIND FLOW ACROSS
THE FORECAST AREA FOR THE NEXT SEVERAL DAYS...WHILE BRINGING MOIST
TROPICAL AIRMASS ACROSS THE REGION.

&&

.DISCUSSION...BIT OF A BREAK OF THE MID TO HIGH CLOUD COVERAGE WITHIN
THE PAST FEW HOURS...HAS RESULTED IN MODERATE TO HEAVY SHOWERS AND
ISOLATED THUNDERSTORMS ACROSS MUCH OF THE NORTHERN SLOPES AND
NORTHERN COASTAL MUNICIPALITIES. THESE WEATHER CONDITIONS WILL
PERSIST ACROSS THOSE AREAS FOR AT LEAST THROUGH THE EARLY EVENING HOURS.

MINOR FLOODING ARE EXPECTED ACROSS SOME OF THESE LOCATIONS...INCLUDING
ROADWAYS...HIGHWAYS...POOR DRAINAGE AREAS AND SMALL RIVER STREAMS. ALSO...THE
RISK OF MUDSLIDES REMAIN HIGH. SIMILAR WEATHER CONDITIONS ARE
EXPECTED FOR THE NEXT FEW DAYS AS ABUNDANT TROPICAL MOISTURE
CONTINUE TO MOVE ACROSS THE LOCAL AREA AND COASTAL WATERS.

&&

.AVIATION...BRIEF MVFR CIGS AND VSBYS WILL BE POSSIBLE IN A QUICK
PASSING SHRA OR TSRA ACROSS...TJBQ AND TJMZ AT LEAST THROUGH
22Z...WITH MOSTLY VFR CONDITIONS EXPECTED TO CONTINUE ACROSS THE
REMAINDER OF THE LOCAL TAF SITES. WINDS WILL BE MAINLY FROM THE
SOUTHEAST AT 10 TO 15 KTS BETWEEN THE SURFACE TO NEAR 10K FEET.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU  75  87  75  86 /  40  50  30  40
STT  75  85  75  84 /  40  50  40  40

&&

.SJU WATCHES/WARNINGS/ADVISORIES...
PR...NONE.
VI...NONE.
&&

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