088
FXCA20 KWBC 251220
PMDCA
TROPICAL DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
819 AM EDT TUE APR 25 2023
PRELIMINARY DISCUSSION FOR PUERTO RICO AND THE USVI FROM APR
25/12UTC: UNDER THE INFLUENCE OF THE SUBEQUATORIAL RIDGE CENTERING
ON A HIGH OVER THE GUAJIRA PENINSULA IN NORTHERN
COLOMBIA...WESTERLY FLOW IN THE UPPER LEVELS CONTINUES ACROSS MOST
OF THE NORTHERN CARIBBEAN. THE SAN JUAN SOUNDING SHOWS AN ELEVATED
TRADE WIND CAP LOCATED NEAR 600 HPA...WHILE THE UNDERLYING LAYER
CONTINUES TO BE CONVECTIVE UNSTABLE. THE ABSENCE OF A SIGNIFICANT
STABLE LAYER BELOW 600 HPA WILL CONTINUE TO FAVOR SOME VERTICAL
DEVELOPMENT AS DIURNAL HEATING DEVELOPS. TOTAL PRECIPITABLE WATER
REMAINS LOW GIVEN THAT THE ISLANDS REMAIN SANDWICHED BETWEEN A
STATIONARY FRONT ALONG 23N AND ANOTHER WEAKENING BOUNDARY THAT
EXTENDS ACROSS THE LEEWARD ISLANDS INTO THE NORTHEAST CARIBBEAN
NEAR 16N. THE MIMIC TPW ANALYSIS SUGGEST VALUES NEAR OR BELOW
30MM. THE TRADES ARE VERY WEAK AND HAVE A NORTHERLY COMPONENT.
SATELLITE IMAGERY SHOWS VERY LITTLE CLOUDINESS IN THE ISLANDS THIS
MORNING...WHICH WILL FAVOR THE ROLE OF DIURNAL BREEZES IN THE
DEVELOPMENT OF CONVECTION LATER IN THE DAY.
MID-UPPER ZONAL FLOW IS FORECAST TO PERSIST THROUGH THE FORECAST
CYCLE. IN THE MID-LEVELS...A WEAK TROUGH PATTERN IS EXPECTED TO
PERSIST ACROSS THE NORTHEAST CARIBBEAN THROUGH THE WORK WEEK.
ALTHOUGH MOISTURE IS EXPECTED TO REMAIN LOW...ESPECIALLY ABOVE 600
HPA...VERTICAL MIXING UNDERNEATH WILL BE SUFFICIENT TO FAVOR
ISOLATED MODERATE AMOUNTS ON A DAILY BASIS. THE TRADES ARE
EXPECTED TO REMAIN VERY WEAK THROUGH THE FORECAST
CYCLE...HIGHLIGHTING THE ROLE OF DIURNAL BREEZES ON THE TRIGGERING
OF CONVECTION. CURRENT WEAK NORTHERLY TRADES ARE EXPECTED TO
GRADUALLY ACQUIRE A SOUTHEASTERLY COMPONENT LATER ON THE DAY ON
TUESDAY. THIS WILL FAVOR AFTERNOON CONVECTION CLUSTERING ALONG THE
CORDILLERA...FAVORING MAXIMA OF 0.5-1 INCH. ON WEDNESDAY AND
THURSDAY...EXPECT SIMILAR AMOUNTS. YET...UNDER THE INFLUENCE OF
SOUTHWESTERLY FLOW IN THE MID-LEVELS...EXPECT AN ENHANCED
POTENTIAL FOR ACCUMULATION IN THE SAN JUAN METRO...WHERE EXPECT
MAXIMA OF 0.5-0.75 INCHES. ON THURSDAY...EXPECT ACCUMULATION OF
0.2-0.5 INCHES ALSO EXTENDING ALONG AND NORTH OF THE CORDILLERA
INTO SOUTHERN PORTIONS OF THE SAN JUAN METRO. DRIER CONDITIONS ON
FRIDAY AND SATURDAY WILL FAVOR A DECREASE IN ACCUMULATIONS.
YET...EXPECT THE FOCUS FOR AFTERNOON CONVECTION TO REMAIN ALONG
AND NORTH OF THE CORDILLERA IN CENTRAL AND WESTERN PUERTO
RICO...WHERE EXPECT MAXIMA IN THE 0.5-0.75 INCH RANGE.
GALVEZ/ACOSTA...WPC (USA)
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page