703
FXCA20 KWBC 091022
PMDCA
TROPICAL DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
621 AM EDT TUE MAY 09 2023
PRELIMINARY DISCUSSION FOR PUERTO RICO AND THE USVI FROM MAY
09/11UTC: A ROBUST MID-LKEVEL RIDGE EXTENDS OVER THE TROPICAL
NORTH ATLANTIC AND HAS A NOSE INTO THE EASTERN AND CENTRAL
CARIBBEAN. THE RIDGE IS EXPANDING WESTWARD...WHICH IS ENHANCING
THE TRADE WIND CAP ACROSS THE CARIBBEAN. SOUNDINGS AND MODEL
SOLUTIONS SUGGEST THE CAP BUILDING NEAR 900-850 HPA ACROSS THE
EASTERN CARIBBEAN. OVER PUERTO RICO AND THE VI...THE TRADES ARE
FROM THE EAST-SOUTHEAST AT 10-15KT. SATELLITE IMAGERY SHOWS
SCATTERED SHALLOW CONVECTION PROPAGATING FROM SOUTHEAST TO
NORTHWEST ACROSS THE VI. SOME OF THIS CONVECTION IS PRODUCING
SHOWERS...PRIMARILY IN NEAR ST. THOMAS AND IN EASTERN PORTIONS OF
ST. CROIX...WHILE LITTLE PRECIPITATION IS ESTIMATED ELSEWHERE.
THE MID-LEVEL RIDGE IS EXPECTED TO BE THE DOMINANT FEATURE THROUGH
THE FORECAST CYCLE. UNDER THIS PATTERN...PRECIPITABLE WATER IS
WILL REMAIN BELOW AVERAGE FAVORING MORE ISOLATED AND LESSER
RAINFALL AMOUNTS THAN THOSE CORRESPONDING TO THIS TIME OF THE
YEAR. HOWEVER...THE CAP IS NOT EXPECTED TO FULLY INHIBIT THE
DEVELOPMENT OF AFTERNOON CONVECTION...ALLOWING FOR ACCUMULATION ON
A DAILY BASIS. UNDER THE INFLUENCE OF SOUTHEASTERLY TRADES ON
TUESDAY AND WEDNESDAY...EXPECT AFTERNOON SHOWERS TO CLUSTER IN
NORTHWEST PUERTO RICO AND PRODUCE MAXIMA GENERALLY IN THE 0.4-0.8
INCH RANGE. A DECREASED SOUTHERLY COMPONENT IN THE TRADES WILL
FAVOR AFTERNOON CONVECTION IN INTERIOR PORTIONS OF NORTHWEST
PUERTO RICO BY THURSDAY...TO PRODUCE SIMILAR AMOUNTS.
A MOIST PLUME MOVES FROM THE SOUTHEAST LATE ON THURSDAY INTO
FRIDAY...RESULTING IN ENHANCED MORNING CONVECTION ACROSS THE VI IN
MORNING HOURS FAVORING MAXIMA OF 0.15-0.25 INCHES. IN THE UPPER
LEVELS...A SHORT WAVE TROUGH IS EXPECTED TO CROSS FROM WEST TO
EAST DURING FRIDAY. THIS WILL HIGHLIGHT AFTERNOON CONVECTION IN
NORTHWEST PUERTO RICO. EXPECT SCATTERED CONVECTION TO PRODUCE
MAXIMA OF 0.5-1 INCH. ON SATURDAY...ALTHOUGH THE UPPER LEVELS ARE
EXPECTED TO BE LESS FAVORABLE FOR THE ENHANCEMENT OF ASCENT...THE
MOIST PLUME IS FORECAST TO LINGER NEAR/NORTH OF PUERTO RICO.
ALTHOUGH THERE ARE DISCREPANCIES ON MODELS ON THE EXACT
POSITIONING OF THE PLUME...PRECIPITABLE WATER WILL LIKELY REMAIN
ABOVE 42MM...TO FAVOR ANOTHER ROUND OF MODERATE CONVECTION IN
WESTERN AND NORTHWESTERN PUERTO RICO IN THE AFTERNOON. AT THE
CURRENT TIME...WE ARE EXPECTING MAXIMA OF 1-1.5 INCHES.
GALVEZ...WPC (USA)
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