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)