956
FXCA20 KWBC 261213
PMDCA
TROPICAL DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
713 AM EST TUE JAN 26 2021
PRELIMINARY DISCUSSION FOR PUERTO RICO AND THE USVI FROM JAN
26/12UTC: ON TUESDAY MORNING...A SURFACE FRONT EXTENDS ALONG 18.5N
OR JUST TO THE NORTH OF PUERTO RICO AND THE VI. SATELLITE IMAGERY
SHOWS ENHANCED TRADE WIND SHOWERS ALONG THE SURFACE
FRONT...DORRING THE NORTHERN VIRGIN ISLANDS AND ENTERING THE
NORTHEAST COAST OF PUERTO RICO. SATELLITE DATA ALSO CONFIRMS THE
PRESENCE OF A CAP/INVERSION...WHICH REFLECTS IN THE HORIZONTAL
SPREAD OF FRONTAL CONVECTION. THIS IS CONSISTENT WITH THE
STABILIZING INFLUENCE OF A LARGE MID-LEVEL RIDGE THAT CENTERS OVER
CENTRAL CUBA/CENTRAL BAHAMAS BUT EXTENDS AN AXIS INTO THE LESSER
ANTILLES. THE INFLUENCE OF THE RIDGE WILL LIMIT ACCUMULATIONS WITH
THE SURFACE FRONT...FORECAST TO PEAK DURING TUESDAY MORNING.
THE FRONT IS FORECAST TO DRIFT SOUTHWARD AND CROSS THE ISLANDS
DURING TUESDAY MORNING...TO POSITION TO THE SOUTH OF PUERTO RICO
AND THE VI BY TUESDAY EVENING. FRONTAL CONVECTION IS FORECAST TO
PEAK DURING THE DAY ON TUESDAY...EMBEDDED IN 15-20KT EASTERLY
TRADES. THIS WILL SUSTAIN THE LARGEST ACCUMULATIONS IN THE VIRGIN
ISLANDS AND ESPECIALLY IN EASTERN PUERTO RICO AND THE
CORDILLERA...WHERE EXPECTING ACCUMULATION OF 0.25-0.5 INCHES.
SCATTERED CONVECTION AND VERY LIGHT ACCUMULATIONS ARE EXPECTED IN
MOST OF PUERTO RICO INTO THE AFTERNOON...WITH THE EXCEPTION OF THE
SOUTHWEST CORDILLERA WHERE ISOLATED MAXIMA NEARING 0.75 INCHES IS
EXPECTED. ON TUESDAY EVENING...LINGERING POST FRONTAL CONVECTION
IS FORECAST TO PEAK IN NORTHEAST PUERTO RICO TO FAVOR MAXIMA OF
0.1-0.2 INCHES. MUCH DRIER CONDITIONS ARE EXPECTED ON WEDNESDAY
AND THURSDAY IN ASSOCIATION WITH A MUCH DRIER AIR MASS LOCATED TO
THE NORTH OF THE FRONT...AS WELL AS A LOW-LEVEL DIVERGENT PATTERN.
ANOTHER FRONT APPROACHES FROM THE NORTH ON FRIDAY...WHILE A SHEAR
LINE ORGANIZES TO THE SOUTHEAST OF THE VIRGIN ISLANDS. GIVEN THAT
CONVECTION WILL ORGANIZE WITH THE FRONT AND SHEAR LINE...PUERTO
RICO AND THE VI ARE FORECAST TO LIE BETWEEN THESE TWO SYSTEMS
DURING THE DAY ON FRIDAY...WHICH WILL RESULT IN VERY LIGHT AND
ISOLATED PRECIPITATION. A WETTER PATTERN IS EXPECTED ON SATURDAY
AS THE NEXT FRONT APPROACHES THE ISLANDS.
GALVEZ...WPC (USA)
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