929
FXCA20 KWBC 281234
PMDCA
TROPICAL DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
734 AM EST WED DEC 28 2022
PRELIMINARY DISCUSSION FOR PUERTO RICO AND THE USVI FROM DEC
28/12UTC: IN THE UPPER LEVELS...A TROUGH EXTENDS FROM A LOW AT 29N
55W INTO THE WINDWARD ISLANDS AND NORTHEAST VENEZUELA. THIS IS
REFLECTS ON A LARGE MID-LEVEL TROUGH OVER THE ARC OF THE LESSER
ANTILLES...WHILE A MID-LEVEL RIDGE EXTENDS FROM THE NROTH ATLANTIC
INTO HISPANILA/PUERTO RICO AND THE SOUTHEAST BAHAMAS. ENHANCED
CONVECTION IS OCCURRING ACROSS THE CENTRAL LESSER ANTILLES IN
ASSOCIATION WITH A BOUNDARY OF ENHANCED TRADE WIND CONVERGENCE.
THIS FEATURE IS CROSSING WESTERN PUERTO RICO ON WEDNESDAY
MORNING...BUT IT HAS LOST ORGANIZATION IN AN ENHANCED LOW-LEVEL
DIVERGENT PATTERN.
THE UPPER TROUGH OVER AND TO THE EAST OF THE LESSER ANTILLES IS
FORECAST TO RETROGRADE SLOWLY WHILE WEAKENING. BY SATURDAY...THE
AMPLIFICATION OF A RIDGE ACROSS JAMAICA/CUBA/BAHAMAS WILL EMPLIFY
A TROUGH TO ITS EAST...WHICH IS FORECAST TO ESTABLISH ITS BASE
ACROSS THE LEEWARD ISLANDS LATE ON SATURDAY. IN THIS
POSITION...THIS TROUGH WILL LIKELY DESTABILIZE TRADE WIND
CONVECTION EAST OF THE LEEWARD ISLANDS DURING THE WEEKEND...WHICH
WILL RESULT IN HIGHER VERTICAL DEVELOPMENT AND ASSOCIATED RAINFALL
RATES IN CONVECTION THAT MOVES INTO THE REGION DURING THE LATE
WEEKEND/EARLY NEXT WEEK. THIS REFLECTS ON GENERALLY LARGER VALUES
OF THE GDI ACROSS THE NORTHEAST CARIBBEAN ON SUNDAY AND
MONDAY...ALTHOUGH NO SPECIFIC SYSTEM ASSOCIATES WITH THE LARGER
VALUES OTHER THAN DESTABILIZATION BY THE UPPER TROUGH. GIVEN TEH
PREVALENCE OF EAST-NORTHEASTERLY TRADES...EXPECT THE LARGEST
ACCUMULATIONS TO CLUSTER IN NORTHEAST PUERTO RICO IN THE FORM OF
LATE EVENING/EARLY MORNING CONVECTION.
GALVEZ...WPC (USA)
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