Prognostic Meteorological Discussion
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FXCA20 KWBC 251039
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TROPICAL DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
638 AM EDT MON JUL 25 2016

PRELIMINARY DISCUSSION FOR PUERTO RICO AND THE USVI FROM JULY
25/06 UTC: UNDER INFLUENCE OF BROAD CELL OF THE BERMUDA RIDGE TO
THE NORTH...A TUTT IS TO MEANDER TO THE SOUTHWEST INTO THE
FORECAST AREA EARLY ON THURSDAY MORNING. HOWEVER...AT MID
LEVELS...IT WILL HAVE TO BATTLE A FAIRLY RESILIENT CELL OF THE
SUBTROPICAL RIDGE DOMINATING THE WESTERN ATLANTIC/NORTHERN
CARIBBEAN ISLES. THE PERSISTENT RIDGE IS TO FAVOR A HIGHLY
ELEVATED INVERSION THAT IS TO TRAP MOISTURE TO ATMOSPHERE BELOW
700 HPA. THIS WILL BE STRONG ENOUGH TO INHIBIT ORGANIZED DEEP
CONVECTION BUT NOT STRONG ENOUGH TO SUPPRESS SHALLOW CONVECTIVE
DEVELOPMENT. AS A RESULT...EXPECTING TRADE WINDS SHOWERS TO AFFECT
THE FORECAST AREA FROM TIME TO TIME AS ENHANCED BY BRISK EASTERLY
TRADES.

EMBEDDED IN THE EASTERLY TRADES...MODELS SHOW AN EASTERLY WAVE
NEARING THE ISLAND CHAIN EARLY ON TUESDAY MORNING...AND PULLING
ACROSS PUERTO RICO DURING THE AFTERNOON. THE GLOBAL MODEL GUIDANCE
ARE IN SURPRISINGLY CLOSE AGREEMENT ON THIS FEATURE...SHOWING
MOISTURE BEST MOISTURE CONVERGENCE OFF THE ATLANTIC WATERS OF
PUERTO RICO. IN RESPONSE...THE KEEP MOST ACTIVE CONVECTION FAR TO
THE NORTH. ACROSS EASTERN PUERTO RICO IT IS TO TRIGGER MODERATE
CONVECTION WITH LOCALIZED MAXIMA OF NEARLY AN INCH DURING THE LATE
MORNING/EARLY AFTERNOON. OVER NORTHWEST PUERTO RICO MOST ACTIVE IS
EXPECTED IN THE AFTERNOON...AS ENHANCED BY SOUTHEASTERLY TRADES
AND DIURNAL HEATING. IN THIS AREA HIGHER RESOLUTION GUIDANCE ONLY
SHOWING MAXIMA OF .5 OF AN INCH. THIS SEEMS REASONABLE CONSIDERING
LACK OF UPPER LEVEL SUPPORT/FORCING.

NEXT CHANCE FOR MEASURABLE RAINFALL AMOUNTS WILL BE LATER ON
FRIDAY AS THE NEXT EASTERLY WAVE CROSSES INTO THE FORECAST AREA.

CABANERIT...INAMEH (VENEZUELA)
CONTRERAS...IMN (COSTA RICA)
CASTILLO...UCR (COSTA RICA)
DAVISON...WPC (USA)

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