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FXCA20 KWBC 021343
PMDCA
TROPICAL DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
942 AM EDT THU MAY 02 2024
WEEKLY DISCUSSION FOR PUERTO RICO AND THE USVI MAY 02/12UTC: A WET
PATTERN IS EXPECTED OVER PR/USVI OVER THE NEXT SEVERAL DAYS. THERE
IS A GOOD CHANCE OF THUNDERSTORMS LATE THIS WEEK INTO THE
WEEKEND...WITH SOME OF THE THUNDERSTORMS WITH THE POTENTIAL OF
BEING STRONG. THE OVERALL MOISTURE WILL BE FROM NORMAL TO ABOVE
NORMAL FOR THE NEXT SEVERAL DAYS...WITH THE LATEST GUIDANCE
SUGGESTING PRECIPITABLE WATER VALUES BETWEEN 1.9 TO 2.3 INCHES
THROUGH THE NEXT 5 TO 7 DAYS...AND PRECIPITABLE WATER AT 2 INCHES
OR HIGHER STARTING ON FRIDAY EVENING. THE LOW TO MID LEVEL
RELATIVE HUMIDITY IS ALSO FORECAST TO BE ABOVE NORMAL FROM FRIDAY
ONWARD. A MID TO UPPER LEVEL TROUGH IS APPROACHING FROM THE
WEST...AND THE 500MB HEIGHT ANOMALY IS VERY PRONOUNCED OVER
HISPANIOLA INTO THE CENTRAL CARIBBEAN...WHILE IT CAUSES THE 500 MB
TEMPERATURES TO BE NEAR -7C TO -8C ON FRIDAY AND SATURDAY OVER THE
LOCAL ISLANDS. OVER THE NEXT FEW DAYS...THE MID LEVEL TROUGH AXIS
WILL REMAIN OVER THE CENTRAL CARIBBEAN...WHILE THE MID AND UPPER
LEVEL WINDS STRENGTHEN OVER THE NORTHEAST CARIBBEAN...CAUSING
STRONG DIVERGENCE ALOFT FROM FRIDAY INTO THE WEEKEND. THE
DIVERGENCE ALOFT...COMBINED WITH THE COLDER MID LEVEL TEMPS...AND
THE INCREASE IN MOISTURE AT ALL LEVELS...WILL CAUSE AN ENHANCED
CHANCE OF THUNDERSTORMS FROM FRIDAY INTO THE WEEKEND. THE EGDI
ALGORITHM DOES SUGGEST THE POTENTIAL FOR SCATTERED
THUNDERSTORMS...ESPECIALLY FOR FRIDAY AFTERNOON INTO
SATURDAY...THOUGH IT CONTINUES TO SUGGEST POSSIBLE ISOLATED TO
SCATTERED THUNDERSTORMS INTO NEXT WEEK AS WELL. THAT SAID...THE
GR02T ALGORITHM SUGGESTS A MARGINAL RISK FOR SEVERE THUNDERSTORMS
FROM FRIDAY INTO THIS WEEKEND. THIS IS POSSIBLY DUE TO THE
POSITIONING OF THE MID LEVEL TROUGH AND THE COLD MID LEVEL
TEMPS...HOWEVER...THE MODEL GUIDANCE DOES NOT TAKE THE -8C MID
LEVEL TEMP CONTOUR OVER PR...KEEPING IT TO THE NORTH OF THE LOCAL
ISLANDS...AND THEREFORE NOT SUGGESTING A HIGHER CHANCE OF SEVERE
THUNDERSTORMS AND HAIL POTENTIAL...THOUGH ISOLATED STRONG STORMS
WITH SMALL HAIL WOULD NOT BE RULED OUT AT THIS POINT. THE GR02T
ALGORITHM DOES NOT SUGGEST POTENTIAL FOR STRONG THUNDERSTORMS
AFTER THIS WEEKEND.
AS MENTIONED ABOVE...THE HIGHER THAN NORMAL MOISTURE IS EXPECTED
TO CONTINUE INTO NEXT WEEK. THE GLOBAL AND LONG RANGE MODELS ARE
SUGGESTING A PERSISTENT AND RELATIVELY NARROW LINE OF MOISTURE
OVER THE NORTHEAST CARIBBEAN...ASSOCIATED WITH A FRONTAL BOUNDARY
EXTENDING FROM THE CENTRAL ATLANTIC. A SFC HIGH PRESSURE OVER THE
WEST TROPICAL ATLANTIC WILL ALSO HELP KEEP THE MOISTURE OVER THE
LEEWARD ISLANDS TO THE WEST INTO HISPANIOLA. THE MID TO UPPER
LEVEL WINDS WILL NOT BE TOO STRONG FOR NEXT WEEK...THOUGH A WEAK
MID LEVEL TROUGH COULD HAVE ITS AXIS OVER HISPANIOLA BY
TUESDAY...BUT THE UPPER LEVEL WINDS ARE FORECAST TO BE GENERALLY
ZONAL. THERE IS SOME DISCREPANCIES IN THE SFC WIND FLOW OVER THE
NORTHEAST CARIBBEAN AMONG THE MODEL GUIDANCE IN THE EXTENDED
FORECAST...THAT IS FOR NEXT TUESDAY INTO WEDNESDAY. THE OVERALL
WIND FLOW COULD DICTATE WHERE THE HIGHEST RAINFALL AMOUNTS COULD
BE EARLY INTO THE MIDDLE OF NEXT...BUT BEING THIS FAR INTO THE
FORECAST PERIOD...THERE IS CONSIDERABLE UNCERTAINTY. THAT BEING
SAID...BOTH GLOBAL MODELS ARE IN AGREEMENT THAT HIGH MOISTURE
CONTENT WILL BE PRESENT OVER THE AREA INTO THE MIDDLE OF NEXT
WEEK...THEREFORE SIGNIFICANT SHOWER ACTIVITY COULD STILL BE
EXPECTED SINCE THERE IS DEEP MOISTURE THAT IS FORECAST. THE IMPACT
OF THE RAINFALL EARLY NEXT WEEK COULD BE SIGNIFICANT...THOUGH
STRONG THUNDERSTORMS ARE NOT EXPECTED EARLY NEXT WEEK...THE SOILS
ACROSS SOME AREAS OF PR/USVI COULD BE SATURATED BY
THEN...CONSIDERING WHAT IS EXPECTED THIS WEEKEND.
ALAMO...WPC (USA)
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