Prognostic Meteorological Discussion
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FXCA20 KWBC 291042
PMDCA

TROPICAL DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
642 AM EDT FRI APR 29 2016

PRELIMINARY DISCUSSION FOR PUERTO RICO AND THE USVI FROM APRIL
29/06 UTC: A PROGRESSIVE SHORT WAVE TROUGH TAKES A BEELINE ACROSS
THE FORECAST AREA DURING THE DAY TODAY...WITH ANOTHER TO FOLLOW
DURING THE DAY ON SATURDAY. UNDER INFLUENCE OF THESE PERTURBATIONS
THE SUBTROPICAL JET IS TO MOVE TO THE NORTHERN CARIBBEAN...EXITING
OVER THE DOMINICAN REPUBLIC/MONA PASSAGE. THIS WILL FAVOR AN UPPER
DIVERGENT PATTERN THAT IS TO CONTINUE VENTING DEEP CONVECTION
ACROSS THE NORTHEAST CARIBBEAN ISLES. THE UNSETTLED AND HIGHLY
UNSTABLE AIR MASS IS FORECAST TO PERSIST THROUGH SUNDAY
EVENING...WITH A POSSIBLE LULL IN ACTIVITY ON MONDAY AHEAD OF THE
NEXT MID/UPPER LEVEL PERTURBATION. A MOIST SOUTHEASTERLY FLOW IS
TO DOMINATE BELOW 800 HPA...TO ENHANCE MOISTURE
TRANSPORT/CONVERGENCE ACROSS THE FORECAST AREA. PWAT OVER THE NEXT
FEW DAYS IS TO RANGE BETWEEN 40-50MM...WITH HIGHER VALUES LIKELY
EARLY NEXT WEEK AS A DEEPER MID/UPPER LEVEL TROUGH AMPLIFIES
ACROSS THE BASIN. THIS IS TO CONTINUE FUELING CONVECTIVE
DEVELOPMENT ACROSS PUERTO RICO-VIRGIN ISLES THROUGHOUT THE MEDIUM
RANGE PERIOD.

ALTHOUGH MODELS DISAGREE ON WHERE THE MOST INTENSE CONVECTION IS
TO DEVELOP...THEY GENERALLY AGREE ON ENVIRONMENTAL CONDITIONS TO
REMAIN FAVORABLE AND CONDUCIVE TO ORGANIZED CONVECTION TO DEVELOP.
GENERAL TREND REMAINS AS PREVIOUSLY NOTED...WITH MODELS SHOWING
CONVECTION BECOMING MORE INTENSE AND WIDESPREAD DURING THE WEEKEND
AS A STRONGER MID/UPPER LEVEL PERTURBATION STREAMS ACROSS THE
FORECAST AREA. A SECOND ROUND OF HEAVY CONVECTION IS POSSIBLE ON
TUESDAY AND ONWARD AS AN EVEN STRONGER/DEEPER TROUGH MOVES ACROSS
THE CARIBBEAN. DAILY RAINFALL AMOUNTS ARE EXPECTED TO RANGE
BETWEEN 1-2 INCHES...WITH LOCALIZED MAXIMA OF 3-5 INCHES. MOST
INTENSE IS TO CLUSTER OVER PUERTO RICO JUST NORTH OF THE
CORDILLERA...WITH A SECONDARY MAXIMA LIKELY ACROSS
CAROLINA-CAGUAS-SAN JUAN METRO AREA AS ENHANCED BY A 700 HPA
SOUTHWESTERLY STEERING FLOW. ACROSS THE VIRGIN ISLES THE THREAT OF
HEAVY RAINS IS NOT AS HIGH TODAY...BUT ON SATURDAY THIS IS LIKELY
TO INCREASE AS MID/UPPER LEVEL PATTERN EVOLVES.

CARDOS...SMN (MEXICO)
CABANERIT...INAMEH (VENEZUELA)
DAVISON/GALVEZ...WPC (USA)
$$





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