596
FXCA20 KWBC 191202
PMDCA
TROPICAL DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
702 AM EST MON DEC 19 2022
PRELIMINARY DISCUSSION FOR PUERTO RICO AND THE USVI FROM DEC
19/12UTC: A MID-LEVEL RIDGE HAS ESTABLISHED AND CENTERS ON A HIGH
OVER WESTERN CUBA WHILE EXTENDING AN AXIS TO THE EAST ACROSS THE
ENTIRETY OF THE GREATER ANTILLES. THIS IS ENHANCING THE TRADE WIND
CAP...WHICH IN SAN JUAN LIES NEAR 730 HPA BASED ON THE 00 UTC
SOUNDING. THE SOUNDING INDEED SHOWS A VERY STRONG CAP AND VERY DRY
AIR ABOVE AND BELOW THE CAP. THIS IS CONSISTENT WITH VERY LIMITED
CLOUD COVER ACROSS PUERTO RICO AND THE VI ON MONDAY MORNING. THE
REMNANTS OF A SHEAR LINE EXTEND ACROSS THE LEEWARD ISLANDS...AND
ARE MEANDERING SLOWLY TO THE NORTH. YET...THE MOIST PLUME AND
SHALLOW CONVECTION ASSOCIATED WITH THIS SYSTEM ARE STILL WELL TO
THE SOUTH OF THE FORECAST AREA.
MODELS SHOW THE MID-LEVEL RIDGE PERSISTING ACROSS THE GREATER
ANTILLES THROUGH THE FORECAST CYCLE. THIS WILL CONTINUE TO FAVOR
DRY CONDITIONS AND THE PERSISTENCE OF A TRADE WIND CAP THROUGH THE
ENTIRE FORECAST CYCLE. VARIABILITY WILL BE MOSTLY ASSOCIATED WITH
MOIST PLUMES IN THE TRADES. THE REMNANTS OF THE SHEAR LINE IS THE
MOST NOTABLE FEATURE...AND IS EXPECTED TO BE RESPONSIBLE FOR A
PEAK IN PRECIPITATION ON TUESDAY INTO EARLY WEDNESDAY...AS IT
PROPAGATES TO THE NORTH AND CROSSES THE ISLANDS DURING THIS
PERIOD. THIS WILL FAVOR THE LARGEST ACCUMULATIONS IN NORTHEAST
PUERTO RICO...WHERE EXPECT MAXIMA OF 0.4-0.6 INCHES THROUGH EARLY
WEDNESDAY...PRIMARILY ACCUMULATING LATE ON TUESDAY THROUGH
WEDNESDAY MORNING. THE MOIST PLUME THEN MEANDERS NORTHWARD LEADING
TO A DECREASE IN THE COVERAGE AND INTENSITY OF ANY CONVECTION. IN
TERMS OF DIURNAL CONVECTION IN THE CORDILLERA...EXPECT ISOLATED
MAXIMA OF 0.2-0.3 INCHES IN THE SOUTHWEST ON MONDAY...INCREASING
TO 0.3-0.4 INCHES IN THE WESTERN CORDILLERA ON TUESDAY. THIS PEAKS
ON WEDNESDAY ACROSS WESTERN AND NORTHWEST PUERTO RICO WHERE EXPECT
MAXIMA OF 0.4-0.5 INCHES...DECREASING THEREAFTER IN TERMS OF
COVERAGE AND INTENSITY.
GALVEZ/ACOSTA...WPC (USA)
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