632
FXCA20 KWBC 141238
PMDCA
TROPICAL DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
838 AM EDT FRI JUL 14 2023
PRELIMINARY DISCUSSION FOR PUERTO RICO AND THE USVI FROM JUL
14/12UTC: DRIER THAN NORMAL AVAILABLE MOISTURE IS EXPECTED
TODAY...WHICH WILL CONTINUE THROUGH SATURDAY. THERE IS A TROPICAL
WAVE THAT WILL MOVE INTO THE SOUTHERN CARIBBEAN LATE SATURDAY INTO
SUNDAY...BUT THE ASSOCIATED MOISTURE WILL BE WELL TO THE SOUTH OF
THE LOCAL ISLANDS...WHILE PR/USVI REMAINS WITH NEAR TO BELOW
NORMAL AVAILABLE MOISTURE...A PATCH OF PARTICULARLY DRY AIR IS
FORECAST LATE SUNDAY AFTERNOON INTO THE EVENING. MOISTURE WILL
INCREASE ON MONDAY AS ANOTHER TROPICAL WAVE...CURRENTLY ALONG 37W
APPROACHES THE LOCAL ISLANDS. A STRONG TRADE WIND INVERSION AT
AROUND 850HPA IS EXPECTED TODAY...WHICH WILL HELP LIMIT CONVECTION
OVER PR. THE INVERSION WILL BE WEAKER ON SATURDAY AND SUNDAY. THE
CHANCES OF RAIN INCREASE ON MONDAY INTO TUESDAY WITH THE
APPROACHING TROPICAL WAVE. DURING THE 5-DAY PERIOD...MONDAY INTO
EARLY TUESDAY IS EXPECTED TO BE THE RAINIEST PERIOD...TODAY IS
EXPECTED TO BE THE DRIEST DAY. ANOTHER PULSE OF SAL IS FORECAST ON
TUESDAY AND FOR THE NEXT FEW DAYS THEREAFTER.
A SFC HIGH PRESSURE ACROSS THE ATLANTIC WILL KEEP E-ESE WINDS
DURING THE NEXT SEVERAL DAYS. A WEAK MID LEVEL HIGH PRESSURE IS
FORECAST TO MEANDER ACROSS THE ATLANTIC FOR THE NEXT SEVERAL DAYS
AS WELL. IN THE UPPER LEVELS...A LOW PRESSURE IN THE WESTERN
CARIBBEAN WILL WEAKEN THIS WEEKEND...POSSIBLY OPENING INTO AN
UPPER TROUGH BRIEFLY WITH AXIS BETWEEN CUBA AND HAITI...CAUSING
SSW WINDS IN THE UPPER LEVELS ACROSS PR/USVI THROUGH MONDAY. THE
ECMWF MODEL GUIDANCE SUGGESTS THAT AN UPPER LEVEL RIDGE WILL MOVE
TO THE EAST OF THE LOCAL ISLANDS BY TUESDAY...WHILE THE DRIER AIR
AND SAHARAN DUST IS EXPECTED TO ALSO MOVE IN.
FOR TODAY...PRECIPITABLE WATER WILL BE BELOW NORMAL...WITH VALUES
NEAR 1.5 INCHES...THEN...RANGING BETWEEN 1.6 AND 1.9 INCHES ON
SATURDAY AND SUNDAY. THAT SAID...A BRIEF PATCH OF DRY AIR COULD
CAUSE PRECIPITABLE WATER TO DIP AS LOW AS 1.3 INCHES ON SUNDAY
AFTERNOON AND EVENING...WHICH IS ROUGHLY 2 STANDARD DEVIATIONS
BELOW NORMAL. MOISTURE AND PRECIPITABLE WATER WILL INCREASE AGAIN
ON MONDAY AND TUESDAY WITH THE EXPECTED TROPICAL WAVE...WITH
VALUES PEAKING NEAR 2.2 INCHES ON TUESDAY.
OVERALL...A TYPICAL WEATHER PATTERN OF BRIEF SHOWERS AFFECTING THE
USVI AND EASTERN PR IN THE OVERNIGHT AND MORNING HOURS IS
EXPECTED...WITH SOME CONVECTION OCCURRING ACROSS WESTERN PR IN THE
AFTERNOONS. HOWEVER...GIVEN THE LIMITED MOISTURE...THE OVERALL
COVERAGE AND AMOUNT OF RAIN IS NOT EXPECTED TO BE TOO SIGNIFICANT.
THE COVERAGE AND INTENSITY OF RAIN COULD BE MORE SIGNIFICANT ON
MONDAY AND TUESDAY AS THE TROPICAL WAVE MOVES IN AND AVAILABLE
MOISTURE INCREASES.
ALAMO/GALVEZ...WPC (USA)
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page