899  
FXCA20 KWBC 062036  
PMDCA  
 
TROPICAL DISCUSSION - INTERNATIONAL DESKS  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
336 PM EST WED NOV 06 2024  
 
FORECAST BULLETIN 06 NOV 2024 AT 2030 UTC:  
 
THE NATIONAL HURRICANE CENTER (NHC) IS ISSUING ADVISORIES ON  
HURRICANE RAFAEL. HURRICANE RAFAEL...NOW A CATEGORY 3 HURRICANE  
WITH WINDS OF 100 KNOTS...IS EXPECTED TO MAKE LANDFALL OVER  
WESTERN CUBA LATER TODAY. IN THE FORECAST TRACK...HURRICANE RAFAEL  
IS EXPECTED TO CONTINUE MOVING NORTHWEST UNTIL EARLY  
THURSDAY...THEN MOVE MORE WESTERLY AS IT ENTERS THE GULF OF  
MEXICO. THE LATEST RAINFALL FORECAST INDICATES THAT PORTIONS OF  
WESTERN CUBA COULD OBSERVE AS MUCH AS 200 TO 400MM OF RAIN OVER  
THE NEXT 3 DAYS...WHILE THE CAYMAN ISLANDS WILL OBSERVE  
DIMINISHING RAINFALL OVER THE NEXT FEW DAYS AS THE HURRICANE MOVES  
AWAY. THAT SAID...PORTIONS OF THE CAYMAN ISLANDS ARE STILL  
FORECAST SIGNIFICANT ADDITIONAL RAINFALL. EVEN THOUGH THE CENTER  
OF RAFAEL IS FORECAST TO BE NORTH OF THE ISLAND BY EARLY  
THURSDAY...A TRAILING BAND WITH SHOWERS AND THUNDERSTORMS MAY  
AFFECT PORTIONS OF WESTERN CUBA ON THURSDAY...AND TO A LESSER  
EXTENT ON FRIDAY. PLEASE SEE THE LATEST ADVISORIES OF THE NATIONAL  
HURRICANE CENTER ON HURRICANE RAFAEL AT WWW.HURRICANES.GOV.  
 
ELSEWHERE IN THE TROPICAL REGION...A FEW FEATURES WILL HAVE AN  
IMPACT ACROSS PORTIONS OF THE CARIBBEAN ISLANDS AND CENTRAL  
AMERICA...CAUSING SIGNIFICANT RAINFALL OVER THE AREA. LOWER  
AMOUNTS OF RAIN ARE EXPECTED ELSEWHERE IN THE TROPICAL  
REGION...MEXICO IN PARTICULAR IS EXPECTED TO REMAIN FAIRLY DRY  
OVER THE NEXT THREE DAYS.  
 
SHOWERS AND THUNDERSTORMS ARE CURRENTLY AFFECTING AREAS AROUND  
PR/USVI AND THE NORTHERN LEEWARDS. THIS IS DUE TO LOW LEVEL  
MOISTURE CONVERGENCE OVER THE AREA...COMBINED WITH MID AND UPPER  
LEVEL TROUGHS. THIS LOCALIZED HIGHER MOISTURE AND MID TO UPPER  
LEVEL INSTABILITY IS ALLOWING FOR THE DEVELOPMENT OF THUNDERSTORMS  
IN THE AREA. THESE THUNDERSTORMS ARE EXPECTED TO CONTINUE THROUGH  
THE AFTERNOON INTO THE EVENING HOURS. IN ADDITION...THE MID AND  
UPPER LEVEL FLOW ACROSS THE NORTHEASTER CARIBBEAN WILL CONTINUE TO  
BE CONDUCIVE TO THUNDERSTORM DEVELOPMENT ACROSS THE EASTERN  
GREATER ANTILLES ON THURSDAY INTO FRIDAY...AS THE LOW LEVEL  
CONVERGENCE AND UPPER LEVEL DIVERGENCE CONTINUES OVER THE AREA.  
THE EGDI ALGORITHM IS SUGGESTING AN AREA WITH ENHANCED  
THUNDERSTORM POTENTIAL MOVING JUST NORTH OF PUERTO RICO INTO THE  
DOMINICAN REPUBLIC. AREAS IN THE PERIPHERY TO THE NORTH AND EAST  
OF THE UPPER LOW WILL ALSO HAVE A CHANCE OF ISOLATED TO SCATTERED  
THUNDERSTORM DEVELOPMENT. BY FRIDAY INTO SATURDAY...A TROPICAL  
WAVE IS EXPECTED TO CROSS THE WINDWARD ISLANDS...AND THE TROPICAL  
WAVE COULD INTERACT WITH THE UPPER TROUGH...ENCOUNTERING  
DIFFLUENCE OVER THE AREA AND ENHANCING THE CHANCES OF THUNDERSTORM  
DEVELOPMENT OVER THE WINDWARD ISLANDS. THE GFS MODEL WAS VERY  
AGGRESSIVE WITH THE AMOUNTS OF RAIN FORECAST...WE WENT UNDER THE  
MODEL WITH THE AMOUNTS DUE TO MODEL DISAGREEMENT AND WAITING FOR  
MORE CONSISTENCY BETWEEN MODEL RUNS. THAT SAID...IT MAY PAY TO  
KNOW THAT THIS MESOSCALE SYSTEM AFFECTING THE NORTHEASTERN  
CARIBBEAN WAS WELL FORECAST BY THE GFS...WHILE NOT SO MUCH BY THE  
OTHER GLOBAL MODELS...SO WE ARE INCLINED TO BE CLOSER TO THE GFS  
IN TERMS OF RAINFALL AMOUNTS OVER THE CARIBBEAN.  
 
ANOTHER AREA TO MONITOR IS CENTRAL AMERICA...PARTICULARLY PORTIONS  
IN AND AROUND COSTA RICA. THE MONSOON TROUGH IS FORECAST TO MOVE  
INTO NICARAGUA AND COSTA RICA OVER THE NEXT FEW DAYS. THIS WILL  
CAUSE A PERSISTENT INFLUX OF DEEP MOISTURE INTO THE PACIFIC COAST  
OF NICARAGUA...COSTA RICA...AND WESTERN PANAMA. THE DAILY RAINFALL  
FORECAST FOR PORTIONS OF CENTRAL AMERICA IS IN THE ORDER OF  
15-20MM WITH MAXIMA BETWEEN 25-80MM DEPENDING ON THE DAY...WITH  
THURSDAY INTO FRIDAY BEING THE WETTEST PERIOD IN THE FORECAST. AS  
MENTIONED ABOVE...MEXICO IS EXPECTED TO REMAIN FAIRLY DRY OVER THE  
NEXT FEW DAYS. THE ONLY AREAS WITH SIGNIFICANT RAINFALL IN THE  
FORECAST ARE SOUTHERN AND SOUTHWESTERN MEXICO...WHERE AMOUNTS  
MAXING OUT AT AROUND 15MM ARE FORECAST EACH DAY.  
 
NORTHERN SOUTH AMERICA IS FORECAST TO HAVE A RELATIVELY TYPICAL  
RAINFALL PATTERN OVER THE NEXT FEW DAYS. RAINFALL TOTALS OF AROUND  
15-25MM ARE FORECAST ACROSS MOST OF THE REGION...BUT WESTERN  
COLOMBIA AND NORTHWESTERN VENEZUELA ARE FORECAST TO OBSERVE HIGHER  
AMOUNTS OF RAIN EACH DAY. THE COAST OF WESTERN COLOMBIA IS  
FORECAST MAX RAINFALL VALUES NEAR 35-80MM ON THURSDAY AND FRIDAY  
INTO EARLY SATURDAY...DUE TO ONSHORE FLOW OF DEEP MOISTURE.  
 
EASTERLY/TROPICAL WAVES INITIALIZED AT 12 UTC  
TYPE SOF INT 07/00 07/12 08/00 08/12 09/00 09/12 10/00 10/12  
TW 13N 53W 54W 56W 58W 60W 62W 64W 67W 69W  
 
A TROPICAL WAVE HAS BEEN INITIALIZED AT 53W AND TO THE SOUTH OF  
13N. THE TROPICAL WAVE IS MOVING VERY SLOWLY TO THE WEST...AND THE  
MODEL GUIDANCE DIFFERS ON ITS FORWARD SPEED IN THE SHORT TERM.  
HOWEVER...THE MODEL GUIDANCE AGREE IN ITS POSITION BY THIS  
WEEKEND. THE TROPICAL WAVE IS EXPECTED TO CROSS THE WINDWARD  
ISLANDS ON FRIDAY NIGHT INTO SATURDAY. THIS PASSAGE OF THE  
TROPICAL WAVE MAY BRING AN INCREASE TO THE SHOWER AND THUNDERSTORM  
ACTIVITY TO THE WINDWARD ISLANDS.  
 
ALAMO...(WPC)  
 

 
 
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