808
FXCA20 KWBC 131204
PMDCA
TROPICAL DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
803 AM EDT TUE JUN 13 2023
PRELIMINARY DISCUSSION FOR PUERTO RICO AND THE USVI FROM JUN
13/12UTC: A MID-LEVEL RIDGE CENTERS NEAR 23N 56W AND EXTENDS OVER
THE ENTIRE EASTERN CARIBBEAN. IN THE LOWER LEVELS...ANOTHER RIDGE
CENTERS NEAR 27N 57W...AND IS STEERING EAST-SOUTHEASTERLY TRADES
ACROSS THE ISLANDS. UNDER UPPER CONVERGENT MJO CONDITIONS...THE
TRADES ARE ACCELERATED TO SPEEDS CIRCA 15-20KT. SATELLITE IMAGERY
SHOWS ISOLATED SHALLOW CONVECTION STREAMING FROM THE EAST ACROSS
THE ISLANDS. THIS IS PRODUCING ISOLATED LIGHT RAIN SHOWERS IN
PORTIONS OF EASTERN PUERTO RICO AND THE VI.
THE MID-LEVEL RIDGE IS FORECAST TO BE THE DOMINANT FEATURE THROUGH
THE FORECAST CYCLE. THE RIDGE IS FORECAST TO MOVE VERY
LITTLE...PROVIDING PERIODS OF ENHANCED STABILITY AND MORE
SO...PLENTY OF DRY AIR ABOVE THE BOUNDARY LAYER. THE ACCELERATED
TRADES WILL FAVOR ENHANCED VERTICAL WIND SHEAR. THIS...IN
COMBINATION WITH MARGINAL STABILITY...WILL FAVOR DRY AIR
ENTRAINMENT PROCESSES AND SHORT RESIDENCE TIMES OF DEVELOPING
CONVECTION...WHICH WILL RESULT IN BELOW-NORMAL PRECIPITATION
AMOUNTS THROUGH THE FORECAST CYCLE. A WAVE IN THE TRADES AND
ASSOCIATED MOIST PLUME MOVES IN FROM THE EAST ON TUESDAY. THIS
WILL FAVOR AN INCREASED CHANCE FOR PRECIPITATION AND ACCUMULATION
ON TUESDAY AND WEDNESDAY. DRIER CONDITIONS FOLLOW ON THURSDAY AND
ON.
UNDER THE INFLUENCE OF ACCELERATED TRADES...EXPECT ENHANCED
LOW-LEVEL MOISTURE CONVERGENCE TO PEAK ALONG EASTERN PUERTO RICO
ON A DAILY BASIS. GIVEN THE DIURNAL CYCLE OF CONVECTION...EXPECT
THE MOST FREQUENT SHOWERS AND ACCUMULATION IN LATE NIGHT/EARLY
MORNING HOURS. UNDER THE INFLUENCE OF THE MOIST PLUME...EXPECT
MAXIMA OF 0.75-1 INCH ON TUESDAY AND WEDNESDAY...DECREASING TO
0.2-0.4 INCHES THEREAFTER. AFTERNOON CONVECTION IN NORTHWEST
PUERTO RICO WILL BE SUBJECT TO ENHANCED WIND SHEAR...WHICH WILL
LIMIT ACCUMULATIONS TO FAR NORTHWEST PUERTO RICO AND TAKE A TOLL
LIMITING MAXIMUM ACCUMULATIONS. ON TUESDAY EXPECT MAXIMA OF
0.2-0.4 INCHES. THIS INCREASES TO 0.4-0.7 INCHES ON
WEDNESDAY...DECREASING TO MAXIMA GENERALLY UNDER 0.3 INCHES
THEREAFTER. IN THE VI...EXPECT LIGHT CONVECTION ON A DAILY BASIS.
FIVE DAY TOTALS INDICATE MAXIMA OF 2-2.75 INCHES IN EASTERN PUERTO
RICO...0.5-0.75 INCHES...AND TOTALS OF 1 TO 1.5 INCHES IN
NORTHWEST PUERTO RICO. ISOLATED HIGHER AMOUNTS ARE ALWAYS POSSIBLE.
GALVEZ/ACOSTA...WPC (USA)
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