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FXCA20 KWBC 101257
PMDCA
TROPICAL DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
756 AM EST FRI FEB 10 2023
PRELIMINARY DISCUSSION FOR PUERTO RICO AND THE USVI FROM FEB
10/12UTC: A SURFACE HIGH PRESSURE ACROSS THE WESTERN ATLANTIC WILL
KEEP EASTERLY WINDS AT AROUND 15-20KT ACROSS THE NORTHEAST
CARIBBEAN TODAY AND THROUGH THE WEEKEND...AS THE HIGH PRESSURE
MOVES EAST. A SURFACE LOW PRESSURE WILL ENTER THE NORTHWESTERN
ATLANTIC ON MONDAY...RELAXING THE LOCAL PRESSURE GRADIENT AND
WEAKENING THE WINDS TO AROUND 5-15KT ON MONDAY AND TUESDAY...WHILE
WINDS BECOME EAST-SOUTHEASTERLY ON MONDAY...RETURNING TO EASTERLY
ON TUESDAY. THEN ON WEDNESDAY...ANOTHER SURFACE HIGH PRESSURE WILL
ENTER THE WESTERN ATLANTIC...CAUSING A SLIGHT INCREASE IN THE
EASTERLY WINDS TO 10-15KT. A DECAYING FRONTAL BOUNDARY IS PRESENT
TO THE NORTH OF THE LOCAL AREA...BUT IT SHOULD DISSIPATE ON
SATURDAY INTO SUNDAY...NOT POSING MUCH OF AN IMPACT TO THE
NORTHEAST CARIBBEAN. A MID LEVEL HIGH PRESSURE IS LOCATED OVER THE
BAHAMAS AND MOVING EAST...STAYING TO THE NORTH OF THE GREATER
ANTILLES. THIS MID LEVEL HIGH WILL BE OVER THE CENTRAL ATLANTIC BY
MONDAY. ALSO...A MID LEVEL LOW OVER THE SOUTHWESTERN CARIBBEAN
WILL GRADUALLY MOVE EAST INTO THE EASTERN CARIBBEAN BY MONDAY AND
TUESDAY. THIS CHANGE IN MID LEVEL CONDITIONS WILL WILL BE
ASSOCIATED WITH CHANGES IN INVERSIONS AT AROUND THE 850MB LEVEL
THIS WEEKEND INTO EARLY NEXT WEEK. HOWEVER...THE LATEST TWIN
GUIDANCE IS SUGGESTING THAT WESTERN PR WOULD NOT BE AFFECTED BY
TRADE WIND INVERSIONS IN THE AFTERNOONS THIS WEEKEND. A TROUGH AT
250MB WITH AXIS OVER THE LEEWARD ISLANDS CONTINUES TO MOVE
EAST...GRADUALLY CAUSING SOME SUBSIDENCE OVER THE LOCAL AREA AND
MAKING IT MORE DIFFICULT FOR AFTERNOON CONVECTION TO AFFECT
WESTERN PR TODAY. HOWEVER...VERY SLIGHT AND WEAK TROUGHINESS IN
THE UPPER LEVELS COULD AFFECT THE POTENTIAL OF AFTERNOON
CONVECTION OVER WESTERN PR ON SATURDAY AFTERNOON AND THEN PERHAPS
AGAIN ON MONDAY. HOWEVER...BY LATE TUESDAY...AN UPPER LEVEL RIDGE
WILL BE MOVING IN TO THE NORTHEAST CARIBBEAN...CAUSING A MORE
STABLE ENVIRONMENT. GIVEN THIS PATTERN...TRADE WIND SHOWERS WOULD
STILL BE THE MAIN REASON FOR RAINFALL ACCUMULATION OVER PR/USVI
TODAY AND FOR THE NEXT SEVERAL DAYS. AFFECTING MOSTLY NORTH AND
EAST PR...AS WELL AS THE USVI. SOME AFTERNOON CONVECTION ACROSS
W/NW PR MAY BE POSSIBLE THIS WEEKEND.
THE AVAILABLE MOISTURE IS NEAR NORMAL THIS MORNING...WITH
PRECIPITABLE WATER VALUES NEAR 1.3 INCHES...BUT IT IS EXPECTED TO
DECREASE AS THE DAY PROGRESSES. THE RAINFALL FORECAST INDICATES UP
TO 0.25 INCHES OF RAIN ACROSS NORTH AND EASTERN PR WITH ONLY
HUNDREDTHS ON AN INCH ACROSS THE USVI. THE PRECIPITABLE WATER WILL
BE UP AND DOWN FROM NEAR NORMAL TO BELOW NORMAL FOR THE NEXT FEW
DAYS...AS PATCHES OF MOISTURE MOVE THROUGH...CAUSING THE
PRECIPITABLE WATER TO BE GENERALLY BETWEEN 1.4 AND 1.1 INCHES OR
SO. THE TRADE WIND INVERSION WILL BE LIMITED...BUT PRESENT FOR
PORTIONS OF THE NORTHEAST CARIBBEAN THIS WEEKEND. THERE WILL BE A
CHANCE OF RAIN EACH DAY...ALTHOUGH MAINLY IN THE WAY OF TRADE WIND
SHOWERS...CAUSING UP TO 0.25 TO 0.5 INCHES OF RAIN EACH DAY OVER
THE NEXT 5 DAY PERIOD...THOUGH NORTHWESTERN PR COULD OBSERVE OVER
0.75 INCHES OF RAIN ON SATURDAY AFTERNOON. AT THIS TIME...SATURDAY
APPEARS TO BE THE DAY WITH HIGHEST AMOUNTS OF RAIN AND THE BEST
CHANCE OF AFTERNOON CONVECTION.
ALAMO/ACOSTA...WPC (USA)
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