Prognostic Meteorological Discussion
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000
FXCA20 KWBC 101115
PMDCA

TROPICAL DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
715 AM EDT THU JUL 10 2014

PRELIMINARY DISCUSSION FOR PUERTO RICO AND THE USVI. TROPICAL WAVE
LIES JUST EAST OF THE WINDWARD ISLES EARLY THIS MORNING. MODEL
GUIDANCE SHOWS THIS PERTURBATION MOVING ACROSS THE VIRGIN ISLES
LATER THIS EVENING...INTO EASTERN PUERTO RICO AROUND MIDNIGHT.
THROUGH THE MORNING HOURS IT IS TO TAKE A BEELINE ACROSS PUERTO
RICO...REACHING THE MONA PASSAGE BY 12UTC ON FRIDAY. TRADES ARE TO
VEER TO THE EAST-SOUTHEAST FOLLOWING WAVE PASSAGE. BUT THIS WILL
BE SHORT LASTING...AS PREVAILING EASTERLIES ARE TO QUICKLY RETURN.
PER SATELLITE DERIVED PWAT ANALYSIS...BEST MOISTURE CONVERGENCE
WITH THIS FEATURE IS ALONG THE ITCZ AND TO THE SOUTH OF BARBADOS.
IN A MID/UPPER CONVERGENT PATTERN...SHALLOWER MOISTURE IS MOVING
INTO THE FRENCH/LEEWARD ISLES. THIS IS TO EXPAND ACROSS THE VIRGIN
ISLES LATER THIS EVENING AND ACROSS PUERTO RICO EARLY ON FRIDAY
MORNING. A DENSE SAHARAN AIR LAYER CLOSELY FOLLOWS THIS
WAVE...CURRENTLY EXPANDING BETWEEN THE LESSER ANTILLES AND THE
CAPE VERDE ISLANDS. AS IT MOVES ACROSS THE LESSER ANTILLES THIS
WILL FAVOR RAPID EROSION OF AVAILABLE MOISTURE THROUGH FRIDAY
EVENING. MODEL GUIDANCE CONTINUES TO SHOW MOST ACTIVE CONVECTION
WITH THIS WAVE BETWEEN THE VIRGIN ISLES-EASTERN PUERTO RICO...WITH
RAINFALL AMOUNTS PEAKING AT 05-10MM...WHILE ACROSS PUERTO RICO
ONLY SHOWING RAINFALL AMOUNTS OF 00-05MM. DEPENDING HOW QUICKLY
THE MOISTURE EBBS...A SECONDARY MAXIMA MIGHT DEVELOP OVER
NORTHWEST PUERTO RICO DURING THE EARLY AFTERNOON HOURS.

RETROGRESSING TUTT LOW IS TO THEN DOMINATE THROUGHOUT THE MEDIUM
RANGE PERIOD...WITH TROUGH/CLOSED LOW TO MEANDER TO THE
NORTH-NORTHEAST OF THE FORECAST AREA INTO EARLY NEXT WEEK.
ALTHOUGH BASE OF THE MID/UPPER TROUGH IS TO REACH THE NORTHEAST
CARIBBEAN ISLES...BEST INSTABILITY IS EXPECTED NORTH OF
23N/24N...WITH MODELS SHOWING ORGANIZED DEEP CONVECTION FORMING IN
THE VICINITY OF THE UPPER LOW. ACROSS PUERTO RICO...CONVECTIVE
ENHANCEMENT IS LIKELY TO LIMIT TO WESTERN INTERIOR PORTIONS OF THE
ISLAND DURING THE AFTERNOON HOURS.

FIGUEROA...MARN (EL SALVADOR)
VALVERDE...IMN (COSTA RICA)
DAVISON...WPC (USA)

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