942
FXCA20 KWBC 211305
PMDCA
TROPICAL DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
904 AM EDT TUE MAR 21 2023
PRELIMINARY DISCUSSION FOR PUERTO RICO AND THE USVI FROM MAR
21/12UTC: TODAY AND WEDNESDAY WILL HAVE MORE RAINFALL SHOWERS THAN
THURSDAY THROUGH SATURDAY...EVEN THOUGH A SLIGHT INCREASE IN
SHOWER ACTIVITY COULD BE OBSERVED LATE FRIDAY INTO SATURDAY
MORNING. THE HIGHEST AMOUNTS OF RAIN TODAY AND WEDNESDAY ARE
EXPECTED TO BE ACROSS EASTERN AND NORTHEASTER PR.
THERE IS STILL A SURFACE HIGH PRESSURE ACROSS THE CENTRAL
ATLANTIC...THAT WILL CONTINUE TO DOMINATE THE WIND FLOW ACROSS
THE NORTHEASTERN CARIBBEAN. THERE IS ALSO A COLD FRONT EXTENDING
FROM THE WESTERN ATLANTIC TO THE WESTERN CARIBBEAN. THE HIGH
PRESSURE IS EXPECTED TO REMAIN ACROSS THE CENTRAL ATLANTIC OVER
THE NEXT SEVERAL DAYS...BUT WILL WEAKEN BY FRIDAY...THEN ANOTHER
SURFACE HIGH PRESSURE WILL MOVE INTO THE WESTERN ATLANTIC ON
FRIDAY AND SATURDAY. THE COLD FRONT WILL MOVE EAST SOUTHEAST AS IT
WEAKENS AND BECOMES STATIONARY BY WEDNESDAY...STILL NORTH OF THE
LOCAL ISLANDS. THIS PATTERN WILL CAUSE A SLIGHT SHIFT IN WIND
DIRECTION FROM EASTERLY TODAY TO NORTHEASTERLY FROM WEDNESDAY
ONWARD THROUGH THE WEEKEND. GIVEN THIS WIND FLOW...THE LIMITED
CONVECTION EXPECTED THIS AFTERNOON OVER PR WILL BE OVER PORTIONS
OF THE NORTHWESTERN QUADRANT OF THE ISLAND. THEN ON WEDNESDAY
ONWARD...THE SHIFT TO A NORTHEASTERLY WIND DIRECTION WILL CAUSE
THE AFTERNOON SHOWERS TO AFFECT PORTIONS OF THE SOUTHWESTERN
QUADRANT OF PR. PATCHES OF MOISTURE WILL BE MOVING IN...CAUSING
NEAR NORMAL TO BELOW NORMAL MOISTURE TODAY...BUT MOISTURE WILL
THEN INCREASE ON WEDNESDAY. THE PRECIPITABLE WATER VALUES WILL BE
BETWEEN 1.1 TODAY AND 1.6 INCHES ON WEDNESDAY. FROM THURSDAY
ONWARD...THE PRECIPITABLE WATER WILL DECREASE AND IS FORECAST TO
REMAIN BETWEEN MAINLY BETWEEN 0.8 AND 1.2 INCHES...WHICH IS BELOW
NORMAL. THE LATEST GUIDANCE STILL SUGGESTS THAT THERE IS NO
SIGNIFICANT TRADE WIND INVERSION TODAY OR WEDNESDAY...BUT STARTING
VERY LATE WEDNESDAY OR EARLY THURSDAY...A MID LEVEL HIGH PRESSURE
MOVES INTO THE GULF OF MEXICO...WHICH WILL BE ASSOCIATED WITH A
TRADE WIND INVERSION OVER THE LOCAL ISLANDS FROM THAT POINT
THROUGH THE WEEKEND.
EVERY DAY THIS WEEK...EASTERN AND NORTHEASTERN PR WILL BE THE
SECTIONS WITH THE HIGHEST AMOUNTS OF RAIN IN PR...TOTALING BETWEEN
A QUARTER AND A HALF AN INCH TODAY...THEN CLOSE TO AN INCH OF RAIN
ON WEDNESDAY...DECREASING SIGNIFICANTLY TO POSSIBLY A TENTH OF AN
INCH OR LESS FOR THURSDAY ONWARD. THE AFOREMENTIONED AFTERNOON
CONVECTION WILL LEAVE LESS THAN A QUARTER OF AN INCH OF RAIN
TODAY...THEN ABOUT THREE QUARTERS TO AN INCH OF RAIN ON WEDNESDAY.
VERY LITTLE...IF ANY RAIN ON THURSDAY AND FRIDAY. ACROSS THE
USVI...TODAY AND WEDNESDAY ALSO APPEAR TO BE THE WETTEST DAYS.
SCATTERED SHOWERS...WILL LEAVE TOTALS NEAR 0.15 INCHES
TODAY...THEN ABOUT A QUARTER OF AN INCH OF RAIN ON WEDNESDAY. FOR
THURSDAY THROUGH SATURDAY...LITTLE TO NO RAIN IS EXPECTED ACROSS
THE USVI.
ACOSTA/ALAMO...WPC (USA)
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