803
FXCA20 KWBC 211247
PMDCA
TROPICAL DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
747 AM EST WED FEB 21 2024
PRELIMINARY DISCUSSION FOR PUERTO RICO AND THE USVI FEB 21/12UTC:
A SFC LOW NEAR 32N/68W CONTINUES TO MOVE TO THE NORTH ACROSS THE
WESTERN ATLANTIC. THIS LOW PRESSURE HAS AN ASSOCIATED COLD FRONT
THAT EXTENDS SOUTH ACROSS HISPANIOLA...THE CARIBBEAN AND INTO THE
CARIBBEAN COAST OF COSTA RICA. THERE IS ALSO A PRE-FRONTAL TROUGH
THAT IS QUICKLY APPROACHING WESTERN PR. AS THE SFC LOW CONTINUES
TO MOVES NORTH...THE COLD FRONT AND THE PRE-FRONTAL TROUGH WILL
MOVE EAST...WITH THE TROUGH PASSING THROUGH THE LOCAL ISLANDS
TODAY...WHILE THE COLD FRONT WILL PASS OVERNIGHT TONIGHT INTO
THURSDAY. THE COLD FRONT IS FORECAST TO BE TO THE EAST OF THE USVI
BY THURSDAY EVENING. THIS WILL CAUSE THE AVAILABLE MOISTURE TO
INCREASE TODAY TO ABOVE NORMAL LEVELS...BUT DECREASE THROUGH THE
DAY ON THURSDAY...THEN THE MOISTURE WILL BE WELL BELOW NORMAL BY
THURSDAY EVENING BEHIND THE COLD FRONT. THE LOCAL WINDS WILL BE
LIGHT AND SOMEWHAT VARIABLE TODAY...BECOMING NORTHWESTERLY TONIGHT
INTO EARLY THURSDAY...GRADUALLY BECOMING NORTHEASTERLY ON FRIDAY
THEN EASTERLY ON SATURDAY. ALL THIS COMBINED WILL CAUSE DECENT
COVERAGE OF SHOWER ACTIVITY WITH ISOLATED THUNDERSTORMS
TODAY...DECREASING ACTIVITY ON THURSDAY...AND A RATHER DRY DAY ON
FRIDAY.
IN THE MID LEVELS...A TROUGH WILL COINCIDE WITH THE FRONTAL
PASSAGE EXPECTED. THE MID LEVEL TROUGH AXIS IS FORECAST TO BE OVER
HISPANIOLA BY THIS AFTERNOON AND OVER THE MONA PASSAGE BY THIS
EVENING...PROVIDING INSTABILITY AND INCREASING THE CHANCES OF
SHOWERS AND THUNDERSTORMS. GIVEN THE POSITION OF THE TROUGH AND
THE EASTERLY MOVEMENT OF THE PRE FRONTAL TROUGH AND COLD
FRONT...THE HIGHEST AMOUNTS OF RAIN TODAY ARE CURRENTLY FORECAST
TO BE ACROSS NORTHERN AND EASTERN PR...THOUGH THERE IS SOME
UNCERTAINTY ON EXACT LOCATION OF SHOWERS AND THUNDERSTORMS AS THE
WINDS ARE EXPECTED TO BE LIGHT. THAT BEING SAID...THE LOW TO MID
LEVEL AVERAGE WINDS HAVE A WESTERLY TO SOUTHWESTERLY
DIRECTION...WHICH WOULD FAVOR SHOWER ACTIVITY ACROSS NORTH AND
EASTERN PR. THE UPPER LEVELS ALSO HAVE A TROUGH APPROACHING THE
ISLANDS TODAY INTO THURSDAY...WHICH WOULD GIVE ADDITIONAL SUPPORT
FOR INSTABILITY AND THUNDERSTORM DEVELOPMENT. THE EGDI ALGORITHM
DOES SUGGEST THE POSSIBILITY OF ISOLATED THUNDERSTORMS...THOUGH
THE STRONGEST SIGNAL IS LATE THIS AFTERNOON INTO
TONIGHT...FAVORING NORTHERN AND EASTERN PR.
THE 5-DAY TOTAL RAINFALL FORECAST SUGGESTS THAT MOST OF THE
NORTHERN HALF OF PR COULD OBSERVE OVER AN INCH OF RAIN...MAINLY
DUE TO THE EXPECTED RAINFALL TODAY AND THURSDAY. BUT THE
NORTHEASTERN SECTIONS COULD OBSERVE UPWARDS OF 2 INCHES OF RAIN.
THE USVI AS WELL AS VIEQUES AND CULEBRA COULD OBSERVE NEAR 0.75 TO
1.5 INCHES. SOUTHERN COASTAL PR IS FORECAST THE LEAST AMOUNT OF
RAIN...WITH TOTALS NEAR 0.25 AND 0.50 INCHES FOR THE 5-DAY PERIOD.
ALAMO...WPC (USA)
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