892
FXCA20 KWBC 061725
PMDCA
TROPICAL DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
124 PM EDT THU JUN 06 2024
FORECAST BULLETIN 06 JUN 2024 AT 1720 UTC:
ABOVE NORMAL MOISTURE WILL PREVAIL ACROSS THE CENTRAL TO WESTERN
CARIBBEAN FOR THE NEXT SEVERAL DAYS. BASED ON THE LATEST
OBSERVATIONS...THE MODEL GUIDANCE IS UNDERESTIMATING THE MOISTURE
CONTENT IN THE CARIBBEAN...AND IT COULD IMPACT THE RAINFALL
SOLUTIONS SUGGESTED BY THE GUIDANCE. HAVING SAID THAT...THE GLOBAL
MODELS ARE IN DECENT AGREEMENT WHEN IT COMES TO THE RAINFALL
FORECAST AND WHERE THE MAX RAINFALL CAN BE EXPECTED THIS
WEEKEND...THOUGH THE MODELS REALLY DIFFER IN THEIR RAINFALL
SOLUTIONS FROM SUNDAY ONWARD. AFTER CAREFUL ANALYSIS...THE GFS
MODEL SEEMS TO BE PERFORMING A BIT BETTER COMPARED TO THE OTHER
GLOBAL MODELS. HOWEVER...THE GFS MODEL SEEMS VERY BULLISH WITH THE
MOISTURE AND RAINFALL FORECAST ACROSS THE CARIBBEAN FROM SUNDAY
ONWARD. FOR THAT REASON...IT IS WORTH MENTIONING THAT CONFIDENCE
IS LOWER THAN NORMAL FOR THE RAINFALL FORECAST EARLY NEXT WEEK.
THERE IS SIMPLY TOO MUCH MODEL DISCREPANCY...AND EVEN
DISCREPANCIES IN THE SAME MODEL FROM RUN TO RUN...WITH THE GFS
MODEL PREVIOUSLY HINTING AT THE POSSIBILITY OF A CENTRAL AMERICAN
GYRE DEVELOPING LATE IN THE WEEKEND INTO EARLY NEXT WEEK...BUT THE
12Z GFS MODEL RUN BACKED OFF FROM THAT IDEA.
BASED ON THE LATEST MODEL GUIDANCE...THIS PERSISTENT ABOVE NORMAL
MOISTURE OVER THE CARIBBEAN MAY CAUSE SIGNIFICANT RAINFALL OVER
ALL OF CENTRAL AMERICA AS WELL AS THE CARIBBEAN ISLANDS WEST OF
HISPANIOLA THIS WEEKEND...WITH THEN UNCERTAINTY INCREASING
SIGNIFICANTLY FOR THE RAINFALL FORECAST FROM SUNDAY
ONWARD...ESPECIALLY FOR THE FORECAST RAIN OVER THE CAYMAN ISLANDS
AND CUBA. BASED ON THE LATEST GUIDANCE...ONE TO THREE INCHES OF
RAIN...WITH ISOLATED AMOUNTS UP TO 6 INCHES (25 - 75 MM ISOLATED
TO 150 MM) ARE SUGGESTED FOR THE 3-DAY RAINFALL ACCUMULATIONS FROM
FRIDAY MORNING INTO MONDAY MORNING ACROSS ALL OF CENTRAL AMERICA
AND THE CARIBBEAN ISLANDS WEST OF HISPANIOLA. IF WE GO FURTHER OUT
IN THE FORECAST...FROM FRIDAY MORNING TO TUESDAY MORNING...THE
4-DAY RAINFALL ACCUMULATIONS ACROSS THE AFOREMENTIONED AREAS ARE
FORECAST TO BE AS MUCH AS 2 TO 4 INCHES OF RAIN ACROSS MANY AREAS
WITH ISOLATED AMOUNTS UP TO 8 INCHES (50 - 100 MM ISOLATED TO 200
MM). ACROSS CENTRAL AMERICA...THERE APPEARS TO BE A GOOD CHANCE OF
SHOWERS AND THUNDERSTORMS EACH DAY INTO THE WEEKEND...BUT MONDAY
MAY BE THE DAY WITH LOWEST RAINFALL ACCUMULATIONS OVER
NICARAGUA...THOUGH SIGNIFICANT RAINFALL COULD OCCUR OVER THE REST
OF THE CENTRAL AMERICAN COUNTRIES...AND IN FACT SUNDAY AND MONDAY
APPEAR TO BE THE RAINIEST DAYS OVER WESTERN CUBA AND THE CAYMAN
ISLANDS.
ALL THIS IS DUE TO SEVERAL FACTORS...NOT ONLY THE PERSISTENT ABOVE
NORMAL MOISTURE...BUT THERE WILL ALSO BE A TROPICAL WAVE MOVING
INTO THE CARIBBEAN. THERE WILL ALSO BE TROUGHS IN THE MID AND
UPPER LEVELS ACROSS THE WESTERN CARIBBEAN THIS WEEKEND INTO EARLY
NEXT WEEK. THE LATEST GFS MODEL DOES FAVOR A SHORTWAVE TROUGH OVER
THE NORTHWESTERN CARIBBEAN ON SUNDAY INTO MONDAY...WHICH WOULD BE
CONSISTENT WITH THE POTENTIAL OF HIGHER RAINFALL AMOUNTS ACROSS
WESTERN CUBA...THE CAYMAN ISLANDS...THE YUCATAN PENINSULA AND
PORTIONS OF NORTHERN CENTRAL AMERICA.
ALL THINGS CONSIDERED...THERE IS CONSIDERABLE UNCERTAINTY GIVEN
THE MODEL DISCREPANCY...BUT ALL GLOBAL MODELS DO SUGGEST THE
POTENTIAL FOR SIGNIFICANT RAINFALL ACROSS THE AREA THIS WEEKEND
INTO EARLY NEXT WEEK. WE WILL MONITOR THE SITUATION CLOSELY AND
UPDATE THIS DISCUSSION AS NECESSARY.
ALAMO (WPC)
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