595
FXCA20 KWBC 121217
PMDCA
TROPICAL DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
816 AM EDT WED APR 12 2023
PRELIMINARY DISCUSSION FOR PUERTO RICO AND THE USVI FROM APR
12/12UTC: A MID-LEVEL RIDGE CENTERS ON A HIGH NEAR 14N 73W OR JUST
TO THE NORTH OF THE GUAJIRA PENINSULA. THE RIDGE EXTENDS INTO THE
THE NORTHEAST CARIBBEAN AND IS HELPING TO SUSTAIN A TRADE WIND CAP
NEAR 850 HPA. THE STABILIZING EFFECTS OF THE RIDGE ARE COMBINING
WITH LOW VALUES OF PRECIPITABLE WATER...WELL UNDER
40MM...RESULTING IN FAIR WEATHER CONDITIONS. IN THE
LOW-LEVELS...THE TRADES REMAIN WEAK...BUT HAVE ACQUIRED AN
EASTERLY COMPONENT AND ARE STARTING TO ACCELERATE. THIS IS
FAVORING POCKETS OF SHALLOW CONVECTION IN SOUTHEAST PUERTO
RICO...AS EVIDENCED BY SATELLITE IMAGERY.
NO SIGNIFICANT PRECIPITATION IS EXPECTED DURING THE FORECAST CYCLE
AS THE REAIN REMAIN UNDER THE INFLUENCE OF THE MID-LEVEL RIDGE AN
THE UPPER CONVERGENT PHASE OF THE MADDEN JULIAN OSCILLATION.
MODELS FORECAST THE RIDGE MEANDERING NORTHWESTWARD TO CENTER
NEAR/JUST TO THE SOUTH OF JAMAICA BY FRIDAY AND REMAIN OVER THE
GULF OF HONDURAS THROUGH THE WEEKEND. THIS WILL ALLOW FOR THE
AMPLIFICATION OF A MID-LEVEL TROUGH OVER THE NORTH
ATLANTIC...FORECAST TO DEEPEN AS FAR SOUTH AS 10N BY SUNDAY. THE
TROUGH WILL FAVOR SOME DESTABILIZATION OF THE TRADE WIND CAP OVER
THE NORTH ATLANTIC...WHICH WILL ENHANCE VERTICAL DEVELOPMENT IN
TRADE WIND CONVECTION THAT ENTERS THE NORTHEAST CARIBBEAN DURING
THE WEEKEND. HOWEVER...LIMITED AVAILABLE MOISTURE AND THE ABSENCE
OF SIGNIFICANT PERTURBATIONS IN PLACE WILL LIMIT CHANCES FOR
SIGNIFICANT PRECIPITATION. A SYSTEM OF INTEREST IS A SURFACE FRONT
THAT IS FORECAST TO REACH 20-22N BY FRIDAY...WHILE GRADUALLY
WEAKENING. ALTHOUGH THE FRONT IS NOT FORECAST TO REACH PUERTO
RICO...ENHANCED NORTHEASTERLIES FROM THURSDAY EVENING THROUGH
SATURDAY WILL ENHANCE SHALLOW CONVECTIVE INSTABILITY SUFFICIENTLY
TO FAVOR A SLIGHT ENHANCEMENT OF LATE EVENING/EARLY MORNING TRADE
WIND SHOWERS IN NORTHERN AND EASTERN PUERTO RICO.
IN TERMS OF EXPECTED TOTALS...UNDER THE INFLUENCE OF EASTERLY
TRADES...THE LARGEST ACCUMULATIONS WILL CLUSTER IN WESTERN PUERTO
RICO ON A DAILY BASIS. NORTHEASTERLY ON FRIDAY WILL FAVOR A
RELOCATION TO SOUTHWEST PUERTO RICO IN THE AFTERNOON. ON
WEDNESDAY...EXPECT MAXIMA OF 0.5-0.75 INCHES. THIS DECREASES TO
0.3-0.4 INCHES ON THURSDAY AND FRIDAY. BUT DEEPER TRADE WIND
CONVECTION MOVING IN FROM THE EAST DURING THE WEEKEND WILL FAVOR A
GRADUAL INCREASE IN ACCUMULATIONS. BY SUNDAY...EXPECT MAXIMA OF
0.5-0.6 INCHES IN WESTERN PUERTO RICO...WHILE ELSEWHERE IN THE
ISLAND EXPECT MAXIMA OF 0.2-0.3 INCHES.
GALVEZ/ACOSTA/ALAMO...WPC (USA)
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