223
FXCA20 KWBC 291241
PMDCA
TROPICAL DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
741 AM EST FRI DEC 29 2023
PRELIMINARY DISCUSSION FOR PUERTO RICO AND THE USVI DEC 29/12UTC:
THE LATEST MODEL GUIDANCE IS FAIRLY CONSISTENT WITH THE PREVIOUS
FORECAST...THE ONLY CHANGES WERE MAINLY TOWARDS THE END OF THE
5-DAY FORECAST PERIOD. GENERALLY FAIR WEATHER IS STILL EXPECTED
THROUGH SUNDAY OVER PR/USVI...AND OVER THE PAST FEW DAYS THE
HI-RES MODELS HAVE BEEN OVER ESTIMATING THE RAINFALL.
THEREFORE...THE CURRENT FORECAST ID VERY CONSERVATIVE WITH THE
RAINFALL AMOUNTS...SUGGESTING DAILY RAIN MAXIMA OF NO MORE THAN A
TENTH OF AN INCH TODAY AND SATURDAY...WHILE INCREASING SLIGHTLY
FOR NORTHERN AND EASTERN PR ON NEW YEARS DAY MORNING...BUT STILL
UP TO 0.15 INCHES OR SO. A PATCH OF MOISTURE LATE MONDAY INTO
TUESDAY MAY CAUSE ANOTHER BRIEF INCREASE IN SHOWER ACTIVITY ACROSS
EASTERN PR. THEN ON TUESDAY INTO WEDNESDAY...THERE WILL BE A
FRONTAL BOUNDARY OVER HISPANIOLA...AND THE GFS MODEL HAS PR/USVI
UNDER A DRY SLOT...WHILE THE ECMWF BRINGS SOME OF THE MOISTURE
AHEAD OF THE FRONTAL BOUNDARY OVER WESTERN PR...THEREFORE
CONFIDENCE IS LOW ON THE LATTER PART OF THE FORECAST PERIOD.
THERE IS A SFC HIGH PRESSURE ACROSS THE NORTHEAST ATLANTIC...A
WEAK LOW PRESSURE IN THE CENTRAL TROPICAL ATLANTIC THAT IS
WEAKENING AND MOVING TO THE EAST NORTHEAST...AND A SFC LOW OFF THE
COAST OF THE NORTHEAST U.S. THAT IS ALSO MOVING NORTH-NORTHEAST.
THIS WILL CAUSE RELATIVELY LIGHT NORTHEASTERLY WINDS OVER THE
LOCAL ISLANDS FOR THE NEXT SEVERAL DAYS...BUT A SFC HIGH PRESSURE
IS EXPECTED TO MOVE INTO THE SOUTHWESTERN ATLANTIC BY
MONDAY...CAUSING AN INCREASE IN THE NORTHEASTERLY WINDS OVER THE
LOCAL ISLANDS. THIS SFC HIGH PRESSURE IS FORECAST TO PUSH A
FRONTAL BOUNDARY SOUTH AND OVER HISPANIOLA...GETTING CLOSE TO THE
LOCAL ISLANDS BUT REMAINING TO THE NORTH AND WEST...WHICH MAY
CAUSE PATCHES OF MOISTURE OVER THE LOCAL ISLANDS...AND IS THE MAIN
REASON FOR THE INCREASE IN SHOWER ACTIVITY ON MONDAY INTO TUESDAY.
THE MID AND UPPER LEVELS WILL CONTINUE TO BE DOMINATED BY RIDGES
OF HIGH PRESSURE...WHICH WILL PROMOTE A STABLE ATMOSPHERE THROUGH
THE FORECAST PERIOD. THE TWIN ALGORITHM IS STILL SUGGESTING A
STRONG INVERSION NEAR 900 - 850 MB TO PERSIST THROUGH THE WEEKEND.
THE 5-DAY TOTAL RAINFALL FORECAST SUGGESTS 0.50 TO .075 INCHES
ACROSS PORTIONS OF NORTHERN AND EASTERN PR...AS WELL AS PORTIONS
OF VIEQUES...CULEBRA...AND ST THOMAS USVI. HOWEVER...ST CROIX AND
ST JOHN ARE FORECAST TO OBSERVE UNDER 0.25 INCHES OF RAIN...AS
WELL AS PORTIONS OF CENTRAL TO WESTERN AND SOUTHERN PR.
ALAMO...WPC (USA)
NOTE...THE NEXT UPDATE WILL BE ON TUESDAY JANUARY 02 2024. HAPPY
NEW YEAR!
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page