969  
FXCA20 KWBC 231301  
PMDCA  
 
TROPICAL DISCUSSION - INTERNATIONAL DESKS  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
901 AM EDT THU MAY 23 2024  
 
WEEKLY DISCUSSION FOR PUERTO RICO AND THE USVI MAY 23/12UTC:  
 
A RELATIVELY RAINY PATTERN IS EXPECTED INTO THE MIDDLE OF NEXT  
WEEK OVER PR/USVI...AS ABOVE NORMAL MOISTURE IS EXPECTED THROUGH  
THE PERIOD. THERE IS ALSO A TROPICAL WAVE THAT IS FORECAST TO  
APPROACH PR/USVI BY MONDAY. CURRENTLY...THERE IS A SFC SHORTWAVE  
TROUGH PASSING OVER PR...WHICH WILL INTERACT WITH A STRONG MID AND  
UPPER LEVEL TROUGH OVER WESTERN HISPANIOLA. GIVEN THIS  
SETUP...PERSISTENT SHOWERS AND A FEW THUNDERSTORMS ARE FORECAST TO  
AFFECT THE ISLANDS...WITH EASTERN PR INTO THE USVI POSSIBLY HAVING  
THE HIGHEST RAINFALL AMOUNTS TODAY. THERE IS ALSO A STRONG SFC  
TROUGH JUST WEST OF HISPANIOLA...WHICH IS ALSO INTERACTING WITH  
THE MID AND UPPER LEVEL TROUGHS...AND IS CAUSING CONVECTION AND  
CLOUDINESS ACROSS PORTIONS OF THE CENTRAL CARIBBEAN INTO THE  
SOUTHERN BAHAMAS...ALL THE WAY NORTH INTO THE TROPICAL ATLANTIC  
NORTH OF THE CARIBBEAN. THE LATEST GLOBAL MODEL GUIDANCE SUGGESTS  
THAT THE SFC TROUGH OVER WESTERN HISPANIOLA WILL MOVE NORTH OVER  
THE NEXT FEW DAYS...WITH THE GFS MODEL DEVELOPING A SFC LOW WELL  
NORTH OF PR/USVI BY FRIDAY MORNING...BUT THE ECMWF MODEL DELAYS  
THE DEVELOPMENT OF THE SFC LOW UNTIL LATE FRIDAY NIGHT. THE GFS IS  
ALSO MORE AGGRESSIVE AND DEVELOPS A STRONGER LOW THAN THE ECMWF.  
REGARDLESS OF THE DEVELOPMENT OF THIS SFC LOW TO THE NORTH OF  
PR/USVI...PERSISTENT MOISTURE FROM THE SOUTH TO SOUTHEAST WILL  
MOVE INTO THE NORTHERN CARIBBEAN ISLANDS THROUGH THE WEEKEND.  
ALTHOUGH THE GLOBAL MODEL GUIDANCE AGREE THAT A SFC HIGH WILL MOVE  
INTO THE WESTERN TROPICAL ATLANTIC EARLY NEXT WEEK...AND THE SFC  
LOW TO MOVE EAST INTO THE CENTRAL ATLANTIC...A TROPICAL WAVE IS  
EXPECTED TO APPROACH PR/USVI BY MONDAY...WHICH WILL MAINTAIN ABOVE  
NORMAL MOISTURE OVER THE LOCAL ISLANDS...AS WELL AS MAINTAIN A  
GOOD CHANCE OF SHOWERS INTO EARLY NEXT WEEK.  
 
THE STRONG MID AND UPPER LEVEL TROUGHS WEST OF HISPANIOLA...WILL  
LIFT AND MOVE NORTH INTO THIS WEEKEND. THAT BEING SAID...ANOTHER  
UPPER TROUGH DEVELOPS ONCE AGAIN WITH AN AXIS OVER CUBA BY EARLY  
NEXT WEEK. THIS UPPER TROUGH MAY PERSIST INTO MIDWEEK...BUT THE  
LATEST GUIDANCE INDICATES THAT THE MID LEVELS WILL HAVE A RIDGE  
OVER MOST OF THE CARIBBEAN. THIS WILL RESULT ONLY IN MARGINAL  
INSTABILITY FOR THE EARLY PART OF NEXT WEEK. HOWEVER...PERSISTENT  
MOISTURE ADVECTION AND A FEW SHORTWAVE TROUGHS WILL KEEP A GOOD  
CHANCE OF RAIN OVER PR/USVI WHEN COMBINED WITH DIURNAL HEATING AND  
LOCAL EFFECTS. ALSO...ACCORDING TO THE LATEST EGDI  
ALGORITHM...THERE IS A CHANCE OF THUNDERSTORMS EACH DAY OVER THE  
NEXT 5 DAYS...WITH SUNDAY HAVING THE LOWEST SIGNAL FOR  
THUNDERSTORMS BUT STILL SHOWING THE POSSIBILITY OF VERY ISOLATED  
THUNDERSTORMS.  
 
OVERALL...A RELATIVELY RAINY PATTERN IS EXPECTED...WITH ISOLATED  
TO SCATTERED THUNDERSTORMS...ESPECIALLY FOR THE REST OF THE  
WORKWEEK INTO THE WEEKEND. AN APPROACHING TROPICAL WAVE AND  
PERSISTENT MOISTURE INFLUX WILL COMBINE WITH DIURNAL HEATING AND  
LOCAL EFFECTS NEXT WEEK...MAINTAINING A CHANCE OF SHOWERS AND  
THUNDERSTORMS INTO THE MIDDLE OF NEXT WEEK.  
 
ALAMO...WPC (USA)  
 

 
 
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