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FXCA20 KWBC 301358
PMDCA

TROPICAL DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
958 AM EDT THU MAY 30 2024

WEEKLY DISCUSSION FOR PUERTO RICO AND THE USVI MAY 30/12UTC:

A RELATIVELY RAINY PATTERN IS EXPECTED OVER THE NEXT SEVERAL DAYS
OVER PR/USVI...ALTHOUGH IT IS NOT PARTICULARLY UNCOMMON FOR THIS
TIME OF YEAR. THAT BEING SAID...THE AVAILABLE MOISTURE IS FORECAST
TO REMAIN SLIGHTLY ABOVE NORMAL INTO NEXT WEEK...WITH THE GFS
MODEL SUGGESTING NEARLY 2 STANDARD DEVIATIONS HIGHER THAN NORMAL
BY TUESDAY OF NEXT WEEK. CONSIDERING THE OVERALL SYNOPTIC PATTERN
OVER THE NEXT SEVERAL DAYS...THE RAINFALL PATTERN OVER PR/USVI
WOULD BE FAIRLY TYPICAL...HAVING THE NORTHWESTERN QUADRANT OF PR
FAVORED TO RECEIVE THE HIGHEST AMOUNTS OF RAIN EACH DAY WITH
AFTERNOON SHOWERS AND THUNDERSTORMS...WHILE THE REST OF PR WOULD
HAVE MORE INSTANCES OF BRIEF SHOWERS AND MORE ISOLATED
THUNDERSTORMS. THE USVI ARE EXPECTED TO OBSERVE SCATTERED SHOWERS
OVER THE NEXT SEVERAL DAYS. THE EGDI ALGORITHM DOES INDICATE THE
POSSIBILITY OF THE AFOREMENTIONED PATTERN...BUT IT DOES INDICATE A
RATHER AGGRESSIVE THUNDERSTORM POTENTIAL FOR NEXT TUESDAY THROUGH
THURSDAY FOR PR/USVI...THOUGH CONFIDENCE WOULD BE LOW CONSIDERING
HOW FAR IT IS IN THE FORECAST PERIOD.

IN TERMS OF THE SYNOPTIC PATTERN...THERE IS A SFC LOW ACROSS THE
NORTHERN CENTRAL ATLANTIC...THAT HAS AN ASSOCIATED COLD FRONT TO
THE SOUTH OF THE LOW...AND A SFC TROUGH THAT EXTENDS INTO THE
NORTHEAST CARIBBEAN NEAR PR/USVI TODAY. THERE IS ALSO A TROPICAL
WAVE EAST OF THE WINDWARD ISLANDS THAT WILL MOVE WEST OVER THE
NEXT FEW DAYS...BUT THE BULK OF THE MOISTURE WILL REMAIN TO THE
SOUTH OF THE LOCAL ISLANDS. HOWEVER...THERE IS ANOTHER TROPICAL
WAVE THAT COULD APPROACH PR/USVI ON SUNDAY INTO MONDAY...WHICH
WILL CAUSE AN INCREASE IN MOISTURE OVER THE ISLANDS. FROM TUESDAY
INTO WEDNESDAY...ANOTHER SFC LOW DEVELOPS AND MOVES INTO THE WEST
CENTRAL ATLANTIC...WHICH WILL CAUSE SOUTHEASTERLY TO SOUTHERLY
FLOW OVER THE EASTERN CARIBBEAN...MAINTAINING THE ABOVE NORMAL
MOISTURE OVER THE LOCAL ISLANDS.

THERE IS A MID LEVEL TROUGH ACROSS THE BAHAMAS INTO THE
NORTHWESTERN CARIBBEAN...AND A MID LEVEL HIGH PRESSURE ACROSS THE
EASTERN CARIBBEAN. BY THIS WEEKEND...A WEAK MID LEVEL LOW COULD
DEVELOP ACROSS THE WESTERN CARIBBEAN...BUT THE MID LEVEL HIGH WILL
PERSIST OVER THE EASTERN CARIBBEAN THROUGH THE WEEKEND. THAT
SAID...BY MONDAY...THE MID LEVEL LOW AND ASSOCIATED TROUGH IS
FORECAST TO AMPLIFY ACROSS THE CENTRAL CARIBBEAN...WITH ITS AXIS
BETWEEN HAITI AND CUBA AND THE MID LEVEL HIGH PRESSURE WILL MOVE
EAST OF THE LEEWARDS. THE UPPER LEVELS ARE NOT TOO DIFFERENT...BUT
WITH A MORE BROAD NATURE. ZONAL WESTERLY WINDS WOULD BE EXPECTED
ACROSS THE NORTHEAST CARIBBEAN THROUGH THE WEEKEND...THEN AN UPPER
TROUGH MOVING INTO THE CENTRAL TO NORTHEASTERN CARIBBEAN BY THE
UPCOMING WORKWEEK INTO THE MIDWEEK.

OVERALL...THIS SYNOPTIC PATTERN WOULD CAUSE THE RAINFALL PATTERN
DESCRIBED ABOVE OVER PR/USVI. HOWEVER...THE SAME SYNOPTIC PATTERN
IS POSES THE THREAT OF SIGNIFICANT RAIN AND THUNDERSTORMS ACROSS
HISPANIOLA EARLY NEXT WEEK. THEREFORE...IT IS WORTH MENTIONING
THAT A SLIGHT SHIFT TO THE EAST OF THESE TROUGHS COMPARED TO WHAT
THE MODEL GUIDANCE IS SUGGESTING COULD MEAN A MORE SIGNIFICANT
RAINFALL EVENT OVER PORTIONS OF PR. IN ADDITION...THE GLOBAL MODEL
GUIDANCE IS NOT IN GREAT AGREEMENT FOR THE OVERALL SYNOPTIC
FEATURES BY LATE THIS WEEKEND AND BEYOND. FOR THAT
REASON...CONFIDENCE IS LOW FOR THE FORECAST VALID IN THE UPCOMING
WORKWEEK.

ALAMO...WPC (USA)


$$