Prognostic Meteorological Discussion
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FXCA20 KWBC 151824
PMDCA

TROPICAL DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
223 PM EDT TUE APR 15 2014

PRELIMINARY DISCUSSION FOR PUERTO RICO AND THE USVI. TUTT LOW NEAR
28N 62W EXTENDS A SHORT WAVE TROUGH ACROSS PUERTO RICO/NORTHERN
LEEWARD ISLES. BEST DIVERGENCE WITH THIS FEATURE REMAINS FAR TO
THE NORTH...WITH WEAK DYNAMICAL FORCING ACROSS THE NORTHEAST
CARIBBEAN ISLES QUICKLY EBBING AWAY AS SUBTROPICAL JET MAXIMA
ROUNDS THE BASE OF THE TROUGH. AT LOW LEVELS...IN A LIGHT EASTERLY
FLOW...SHALLOW MOISTURE IS POOLING ACROSS THE FORECAST AREA...WITH
SATELLITE DERIVED PWAT SHOWING BETWEEN 25-30MM OF AVAILABLE
MOISTURE. THIS WAS ENOUGH TO SUSTAIN PESTERING TRADE WIND SHOWERS
ACROSS THE VIRGIN ISLES AND PORTIONS OF PUERTO RICO EARLY THIS
MORNING.

TUTT/TUTT LOW ARE TO QUICKLY MOVE EAST OF THE LESSER ANTILLES AS A
RELOCATING UPPER LEVEL RIDGE SETTLES OVER THE EASTERN
CARIBBEAN-WESTERN ATLANTIC ALONG 64W/65W. THE FORECAST AREA IS TO
THEN REMAIN ON THE CONVERGENT SIDE OF THIS RIDGE AS IT IS EXPECTED
TO HOLD THROUGH THE END OF THE WEEK. THE CAP INVERSION IS TO
INTENSIFY EARLY THIS CYCLE...THEN STARTS TO LIFT/WEAKEN LATER ON
WEDNESDAY. THIS WILL ALLOW FOR A SLIGHT INCREASE IN PWAT AMOUNTS
BY THE MIDDLE OF THE WEEK...WHEN IT IS EXPECTED TO PEAK AT
30-35MM. NOTE THAT THE GFS IS ABOUT 18-24 HRS FASTER THAN THE
EUROPEAN IN BRINGING ADDITIONAL MOISTURE TO THE FORECAST AREA. AT
LOW LEVELS...LIGHT EASTERLY TRADES WILL PREVAIL THROUGH MIDDAY ON
WEDNESDAY. HOWEVER...THROUGH TUESDAY MORNING...AS PRESSURE
GRADIENT TIGHTENS...THE TRADES WILL INCREASE TO 20-25KT. THIS IS
TO ENHANCE LOW LEVEL MOISTURE CONVERGENCE ACROSS THE FORECAST
AREA...WHILE ALSO FAVORING GENERATION OF STREAMERS ACROSS THE
LESSER ANTILLES.

ALTHOUGH LOW LEVEL MOISTURE IS TO INCREASE...MESO/SYNOPTIC FORCING
WILL REMAIN ABSENT. AS A RESULT...ONLY EXPECTING LIGHT WIDELY
ISOLATED CONVECTION TO BUILD OVER THE NEXT FEW DAYS. MOST ACTIVE
TO AFFECT THE VI/EASTERN PUERTO RICO IN THE MORNING HOURS AND
WESTERN INTERIOR PORTIONS OF PUERTO RICO IN THE EARLY AFTERNOON.
THIS FORECAST IS WELL SUPPORTED BY THE GLOBAL MODELS.


DAVISON...WPC (USA)
GARCIA...SMN (MEXICO)
FIGUEROA...MARN (EL SALVADOR)
$$





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