668
FXCA20 KWBC 031234
PMDCA
TROPICAL DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
734 AM EST TUE JAN 03 2023
PRELIMINARY DISCUSSION FOR PUERTO RICO AND THE USVI FROM JAN
03/12UTC: IN AN ENHANCED LARGE SCALE UPPER DIVERGENT/WET PATTERN
ASSOCIATED WITH THE MJO...AN EXTENSIVE UPPER TROUGH LIES ALONG 30N
55W INTO NORTHERN HISPANIOLA. THIS TROUGH IS PROPAGATING TO THE
SOUTHEAST. IN THE LOWER LEVELS...A MOIST POOL EXTENDS TO THE
NORTHEAST OF THE LEEWARD ISLANDS PRIMARILY BETWEEN 18N 56W AND 25N
58W. THIS PLUME IS MEANDERING SOUTHWESTWARD AS IT INTERACTS WITH
THE UPPER TROUGH. LOW-LEVEL WINDS IN PUERTO RICO AND THE VI ARE
FROM THE NORTHEAST...AND THIS ASSOCIATES WITH SCATTERED SHALLOW
TRADE WIND CONVECTION...WHICH IS EVIDENCED BY THE SATELLITE
PRESENTATION AND CONFIRMED BY THE SAN JUAN RADAR. EMBEDDED IN THIS
SCATTERED SHOWER FIELD...A SOLID LINE OF SHOWERS IS PROPAGATING
SOUTHWESTWARD IN INTERIOR PORTIONS OF NORTHEAST PUERTO RICO.
CONSISTENT WITH PREVIOUS SOLUTIONS...THE MODELS CONTINUE RESOLVING
THE FORMATION OF A TUTT LOW TO THE NORTH OF THE ISLANDS LATE ON
TUESDAY. THE LOW IS THEN FORECAST TO MEANDER SOUTHWESTWARD AND
CENTER OVER PUERTO RICO DURING THE ENTIRE DAY ON WEDNESDAY...AND
OVER THE DOMINICAN REPUBLIC ON THURSDAY. A POLAR TROUGH EXITS THE
US EASTERN SEABOARD ON THURSDAY INTO FRIDAY. THIS LARGE TROUGH IS
THEN EXPECTED TO DRAW THE TROUGH OVER HISPANIOLA
NORTHWARD...DECREASING ITS EFFECTS ON NORTHERN CARIBBEAN
CONVECTION FROM FRIDAY AND ON. AS THE TUTT MOVES ACROSS THE REGION
AND INTERACTS WITH THE AFOREMENTIONED MOIST PLUME LOCATED EAST OF
THE LEEWARD ISLANDS...EXPECT A WETTER-THAN-NORMAL NEXT THREE DAYS
IN PUERTO RICO AND THE VI. UNDER THE INFLUENCE OF ACCELERATED
EASTERLY FLOW...THE LARGEST ACCUMULATIONS ARE STILL EXPECTED IN
EASTERN PORTIONS OF THE ISLAND PEAKING DURING THE EARLY MORNING.
LATE ON TUESDAY INTO EARLY WEDNESDAY...EXPECT MODERATE
PRECIPITATION IN EASTERN PUERTO RICO AND THE NORTHERN VI...WHERE
AMOUNTS WILL REACH 0.75-1 INCH. ALONG THE NORTH COAST OF PUERTO
RICO...CONTINUED NORTHEASTERLY LOW-LEVEL FLOW WILL FAVOR MAXIMA OF
0.2-0.4 INCHES. ON WEDNESDAY AFTERNOON...THE TUTT WILL PROVIDE
SUFFICIENT DESTABILIZATION TO ENHANCE AFTERNOON CONVECTION IN THE
WESTERN CORDILLERA. YET...ENHANCED LOW-LEVEL SHEAR WILL LIMIT
MAXIMA TO 0.5-0.75 INCHES. LATE EVENING/MORNING CONVECTION WILL
PEAK ONCE AGAIN IN EASTERN PUERTO RICO ON THURSDAY MORNING...TO
FAVOR MAXIMA OF 0.4-0.6 INCHES...WHILE IN THE NORTHERN VI EXPECT
MAXIMA OF 0.2-0.4 INCHES. AFTERNOON CONVECTION IN THE WESTERN
CORDILLERA WILL SUSTAIN MAXIMA OF 0.3-0.5 INCHES. EXPECT A SIMILAR
DISTRIBUTION OF PRECIPITATION IN FRIDAY...WITH A SHIFT OF MAXIMA
TOWARDS NORTHWEST PUERTO RICO AS SOUTHEASTERLY TRADES PREVAIL.
ACCUMULATIONS SHOULD DECREASE ON SATURDAY...ALTHOUGH CONFIDENCE ON
THE EVOLUTION OF THE UPPER TROUGH AND THE ASSOCIATED RESPONSE OF
SYSTEMS IN THE LOW LEVELS IS STILL LOW AT THIS TIME.
GALVEZ...WPC (USA)
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