040
FXCA20 KWBC 261248
PMDCA
TROPICAL DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
747 AM EST FRI JAN 26 2024
PRELIMINARY DISCUSSION FOR PUERTO RICO AND THE USVI JAN 26/12UTC:
THE MID-LEVEL RIDGE CENTERS OVER THE CENTRAL BAHAMAS AND EXTENDS
OVER THE ENTIRE CENTRAL AND EASTERN CARIBBEAN. THIS IS FAVORING A
TRADE WIND CAP THAT SITS NEAR 850 HPA ACCORDING TO THE SAN JUAN 00
UTC SOUNDING AND WPC'S TRADE WIND ALGORITHM. IN THE LOW
LEVELS...WINDS ARE FROM THE EAST NORTHEAST PEAKING AT SPEEDS OF
20-25KT NEAR THE 925 HPA LEVEL. THIS SHALLOW STRATOCUMULUS AND
VERY LIGHT RAIN SHOWERS IN PORTIONS OF EASTERN PUERTO RICO.
THE MID-LEVEL RIDGE IS FORECAST TO HOLD THROUGH LATE SATURDAY TO
THEN START TO GRADUALLY WEAKEN. THIS YIELDS TO A LARGE POLAR
TROUGH ENTERING THE AREA ON MONDAY. MODELS ARE SUGGESTING A SHEAR
LINE CROSSING THE ISLANDS RAPIDLY LATE ON MONDAY INTO TUESDAY.
RAPID PROGRESSION AND LIMITED AVAILABLE MOISTURE WILL LIKELY FAVOR
CONSERVATIVE RAINFALL AMOUNTS...FORECAST IN THE 0.1-0.2 INCH RAIN
FOR MOST OF PUERTO RICO. THE ASSOCIATED FRONT WILL LIKELY STALL
OVER OR JUST TO THE NORTH OF NORTHERN PUERTO RICO BY MID-WEEK.
HOWEVER...IT IS TOO EARLY GAIN CONFIDENCE IN THE PRECISE EVOLUTION.
IN THE MEAN TIME...PRECIPITATION ON FRIDAY THROUGH SUNDAY WILL BE
MOSTLY MODULATED BY MOIST PLUMES IN THE TRADES. A MOIST PLUME IS
FORECAST TO MOVE INTO THE REGION VERY EARLY ON SATURDAY AND EXIT
LATE DURING THE DAY. THIS WILL FAVOR A SLIGHT INCREASE IN
ACCUMULATION ON SATURDAY. GIVEN THE PRESENCE OF THE TRADE WIND
CAP...EXPECT THE LARGEST ACCUMULATIONS TO GENERALLY CLUSTER IN
EASTERN PUERTO RICO. AS THE CAP ERODES SLIGHTLY ON SATURDAY AND
SUNDAY...EXPECT ISOLATED AFTERNOON CONVECTION IN WESTERN PUERTO
RICO...TO FAVOR MAXIMA UNDER 0.1 INCH. IN EASTERN PUERTO RICO AND
NORTHEAST PUERTO RICO...EASTERLY AND EAST-NORTHEASTERLY FLOW WILL
FAVOR AMOUNTS IN THE 0.15-0.25 INCH/DAY RANGE ON
FRIDAY...INCREASING TO 0.2-0.4 INCH/DAY ON SATURDAY...DECREASING
AFTER. YET...NOTE THAT ANY ACCUMULATION OVER 0.2 INCHES WILL BE
ISOLATED.
GALVEZ/ACOSTA...WPC (USA)
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