Prognostic Meteorological Discussion
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TROPICAL DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
637 AM EDT MON MAY 04 2015

PRELIMINARY DISCUSSION FOR PUERTO RICO AND THE USVI FROM MAY 04/06
UTC: FORECAST AREA REMAINS UNDER INFLUENCE OF A WELL
ENTRENCHED/DEEP LAYER RIDGE THAT DOMINATES THE TROPICAL ATLANTIC
AND THE EASTERN CARIBBEAN. AT LOW/MID LEVELS...PERSISTENT RIDGE TO
THE EAST FAVORS A SOUTHEASTERLY FLOW ACROSS THE ISLAND CHAIN TO
THE NORTHEAST CARIBBEAN ISLES. EMBEDDED IN THIS FLOW...SHALLOW
MOISTURE IS LIFTING ALONG THE EASTERN FRINGES OF THE RIDGE AND
ACROSS THE LESSER ANTILLES...WITH PWAT CONTENT OF 25-30MM.

MID LEVEL RIDGE PATTERN IS TO GENERALLY HOLD THROUGH THE MEDIUM
RANGE PERIOD. ONLY CHANGE EXPECTED IS AN INCREASE IN UPPER CLOUDS
EARLY ON WEDNESDAY MORNING AS A HIGH AMPLITUDE TROUGH ESTABLISHES
FAR TO THE WEST. THIS IS TO PERSIST THROUGH THE END OF THE WEEK.
AS THE RIDGE ALOFT HOLDS...THE CAP INVERSION ENVELOPING FORECAST
AREA IS TO PERSIST. LOW LEVEL WINDS ARE TO RETAIN A SOUTHEASTERLY
COMPONENT OVER THE NEXT FEW DAYS...WITH ANOTHER TRADE WIND SURGE
TO ENTER THE LESSER ANTILLES LATER ON WEDNESDAY/EARLY THURSDAY
MORNING TO BRING ANOTHER BATCH OF DENSE SAHARA DUST ACROSS THE
EASTERN CARIBBEAN. IN THIS PATTERN...MODELS CONTINUE TO FAVOR
MOSTLY FAIR WEATHER CONDITIONS WITH THE OCCASIONAL TRADE WIND
SHOWER PESTERING THE USVI/EASTERN PUERTO RICO. DIURNAL
CONVECTION...IF ANY...IS TO CONFINE TO NORTHWEST PORTIONS OF
PUERTO RICO. BUT AS A DENSE CI/CS CLOUD SHIELD ESTABLISHES ACROSS
THE NORTHEAST CARIBBEAN AND A DRYER SAL ENTERS THE FORECAST AREA
ON WEDNESDAY...CHANCES FOR CONVECTION WILL BE HIGHLY REDUCED AS
THE WEEK WEARS ON.

DISCUSSION FROM MAY 04/12 UTC:

TROPICAL/EASTERLY WAVES INITIALIZED AT 12UTC
INITIAL  24     36     48     60     72     84     96        TYPE
NONE

CRAIG...TTMS (TRINIDAD AND TOBAGO)
SAMUEL...MDS (SURINAME)
DAVISON...WPC (USA)
$$





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