269  
FXCA20 KWBC 031338  
PMDCA  
 
TROPICAL DISCUSSION - INTERNATIONAL DESKS  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
938 AM EDT THU OCT 03 2024  
 
WEEKLY DISCUSSION FOR PUERTO RICO AND THE USVI OCT 03/12UTC:  
 
THERE ARE SEVERAL FEATURES IN THE REGION TO CONSIDER FOR THE  
RAINFALL PATTERN OVER PR/USVI OVER THE NEXT FEW DAYS. THAT BEING  
SAID...WE CAN EXPECT A CHANCE OF BRIEF SHOWERS EACH MORNING ON THE  
WINDWARD SIDE OF PR...AND ACROSS THE USVI...WHILE AFTERNOON  
CONVECTION WITH ISOLATED THUNDERSTORMS ARE FORECAST EACH DAY  
ACROSS AREAS OF SEA BREEZE CONVERGENCE IN PR. THE LOCATION OF  
THESE AFTERNOON ISOLATED THUNDERSTORMS WILL VARY DEPENDING ON THE  
OVERALL WIND DIRECTION AND SPEED AND ITS INTERACTIONS WITH THE  
LOCAL OROGRAPHY. THE TOTAL 5-DAY RAINFALL FORECAST OVER PR COULD  
BE AS MUCH AS 3-5 INCHES OR SO ACROSS PORTIONS OF EASTERN  
PR...WITH THE HIGHEST ACCUMULATIONS EXPECTED ACROSS THE CAYEY  
MOUNTAIN RANGE INTO SOUTH CENTRAL PR...WITH 1-2 INCHES OF RAIN  
FORECAST ACROSS THE NORTHWESTERN QUADRANT OF PR. THE USVI ARE  
FORECAST A 5-DAY TOTAL IN THE ORDER OF 1-2 INCHES AS WELL...MOSTLY  
DUE TO ISOLATED TO SCATTERED SHOWER ACTIVITY EACH DAY.  
 
OVER THE NEXT FEW DAYS...THERE WILL BE A PERSISTENT NORTHEASTERLY  
WIND FLOW AS A SFC LOW PRESSURE ACROSS THE WESTERN ATLANTIC  
MEANDERS OVER THE AREA. THE WINDS WILL REMAIN GENERALLY  
NORTHEASTERLY THROUGH EARLY SATURDAY...BUT WILL WEAKEN AND BECOME  
VERY LIGHT THIS WEEKEND AS THE AFOREMENTIONED SFC LOW STARTS  
INTERACTING WITH THE CURRENT HURRICANE KIRK. THIS INTERACTION WILL  
CAUSE A COL OVER THE LOCAL ISLANDS BY SUNDAY. WITH THIS COL  
DEVELOPING ON SUNDAY...THE WINDS WILL BE LIGHT AND VARIABLE INTO  
THE NEXT WORKWEEK. THAT BEING SAID...THE LATEST MODEL GUIDANCE  
SUGGESTS LIGHT SOUTHERLY WINDS ACROSS THE AREA ON SUNDAY...BUT THE  
WINDS ARE EXPECTED TO BE LIGHT ENOUGH THAT A STRONG SEA BREEZE  
INFLUENCE MAY OCCUR ACROSS NORTHERN INTO CENTRAL PR...CAUSING  
CONVERGENCE OVER THE AREA IN THE LOW LEVELS.  
 
IN THE MID LEVELS...A TROUGH WITH ITS ASSOCIATED LOW IS LOCATED TO  
THE NORTH OF PR/USVI...AND IS EXPECTED TO DRIFT  
SOUTHEASTWARD...POSITIONING ITSELF AROUND 32N/62W BY SATURDAY  
MORNING...THEN FLATTENING AS IT INTERACTS WITH KIRK...THOUGH A MID  
LEVEL TROUGH COULD DEVELOP WITH ITS AXIS JUST WEST OF HISPANIOLA  
ON SUNDAY...LIFTING BY SUNDAY NIGHT. THERE IS ALSO A MID LEVEL  
HIGH PRESSURE RIDGE OVER THE WESTERN GREATER ANTILLES...EXTENDING  
TO THE LOCAL ISLANDS BY EARLY FRIDAY. ALTHOUGH THE LOCAL ISLANDS  
WILL BE INFLUENCED BY THE MID LEVEL TROUGH THIS WEEKEND...A MID  
LEVEL HIGH PRESSURE WILL MOVE INTO THE CARIBBEAN EARLY IN THE  
WORKWEEK. THE UPPER LEVELS WILL BEHAVE SIMILARLY...THERE IS AN  
UPPER LOW AND ASSOCIATED TROUGH ACROSS THE WESTERN ATLANTIC...THAT  
IS EXPECTED TO MOVE EAST AND WEAKEN...BUT A TROUGH WILL DIG INTO  
HISPANIOLA THIS WEEKEND. HOWEVER...FOR THE UPCOMING WORKWEEK...THE  
HIGH PRESSURE CURRENTLY ACROSS THE WESTERN GREATER ANTILLES WILL  
STRENGTHEN AND EXTEND EAST AND OVER THE LOCAL ISLANDS. THE OVERALL  
MOISTURE IS EXPECTED TO BE NEAR NORMAL OVER THE NEXT SEVERAL  
DAYS...BUT THERE WILL BE BRIEF PATCHES OF HIGHER AND LOWER  
MOISTURE MOVING THROUGH.  
 
THIS GENERAL SYNOPTIC PATTERN...AND AVAILABLE MOISTURE...WILL BE  
CONDUCIVE FOR THE LOCAL EFFECTS TO HAVE A STRONG INFLUENCE ON THE  
LOCATION OF THE AFTERNOON CONVECTION. THE TEMPERATURE IN THE MID  
LEVELS ARE WARMER THAN NORMAL...THE MID TO UPPER LEVELS ARE NOT  
PARTICULARLY FAVORABLE FOR STRONG CONVECTIVE SUPPORT...AND THE  
RELATIVE HUMIDITY IN THE LOW TO MID LEVELS WILL BE NEAR NORMAL  
OVER THE NEXT SEVERAL DAYS. CONSIDERING THIS PATTERN...AND THE  
OUTPUT FROM THE EGDI ALGORITHM...THE THUNDERSTORMS THAT DO OCCUR  
IN THE AFTERNOONS ARE EXPECTED TO BE ISOLATED...AND THE GR02T  
SEVERITY ALGORITHM DOES NOT SHOW AREAS AT RISK FOR SEVERE  
THUNDERSTORMS.  
 
ALAMO...WPC (USA)  
 

 
 
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