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Tropical Discussion
 
(Caution: Version displayed is not the latest version. - Issued 1132Z Apr 02, 2020)
 
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TROPICAL DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
732 AM EDT THU APR 02 2020

PRELIMINARY DISCUSSION FOR PUERTO RICO AND THE USVI FROM APR 02/11
UTC: A DEEPENING POLAR TROUGH IS TO QUICKLY BECOME THE DOMINANT
MID/UPPER LEVEL FEATURE OVER THE WESTERN ATLANTIC/NORTHERN
CARIBBEAN ISLANDS. AS IT AMPLIFIES ACROSS THE BASIN...THIS
CONTINUES TO INTERACT WITH A SHORT WAVE TROUGH OVER THE
CARIBBEAN...DRAWING THIS VORTEX EASTWARD ACROSS JAMAICA/CENTRAL
CARIBBEAN EARLY IN THE CYCLE. THROUGH THE DAY THE SHORT WAVE
TROUGH IS TO GRADUALLY SHEAR...SENDING SHORT WAVE VORTICES ACROSS
HISPANIOLA TO PUERTO RICO OVER THE COURSE OF THE NEXT COUPLE OF
DAYS. BUT THE BULK OF THE ENERGY IS TO STREAM SOUTH OF THE
FORECAST AREA ON SATURDAY TO SUNDAY. THE AMPLIFYING TROUGH...AND
THE INFLOW OF MID LEVEL SHORT WAVE ENERGY...WILL RESULT IN THE
GRADUAL EROSION OF TRADE WINDS INVERSION ENVELOPING THE FORECAST
AREA THROUGH SATURDAY MORNING. AT UPPER LEVELS...MODELS
CONSISTENTLY SHOW A SUBTROPICAL JET MAXIMA LIFTING ACROSS THE
FORECAST AREA LATER IN THE WEEK...WITH DIVERGENCE ON ITS RIGHT
ENTRANCE REGION LIKELY TO VENT CONVECTIVE DEVELOPMENT EARLY DURING
THE WEEKEND. BUT THIS WILL BE SHORT LASTING...WITH FORECAST AREA
TO FALL ON THE CONVERGENT LEFT ENTRANCE REGION AS THE JET SHIFTS
SOUTHWARD LATER ON SUNDAY-MONDAY. AT LOW LEVELS...WINDS CONTINUE
TO VEER TO THE SOUTH-SOUTHEAST...DRAWING A PLUME OF SHALLOW
MOISTURE ACROSS THE EASTERN CARIBBEAN TO THE FORECAST AREA...WITH
PWAT CONTENT OF NEARLY AN INCH BY THIS AFTERNOON. THROUGH THE END
OF THE WEEK...A DEEP LAYER WEST-SOUTHWEST FLOW IS TO ESTABLISH
ACROSS THE FORECAST AREA AS THE BROAD POLAR TROUGH SETTLES OVER
THE ATLANTIC. SIMULTANEOUSLY...THE ASSOCIATED SURFACE FRONT
MEANDERS SOUTH INTO NORTHERN HISPANIOLA ON FRIDAY...ENTERING
PUERTO RICO LATER ON SATURDAY. AS IT NEARS THE FORECAST AREA THIS
WILL ENHANCE MOISTURE CONVERGENCE...WITH PWAT CONTENT INCREASING
TO 1.5-1.75 INCHES AS DEEPER INSTABILITY ENVELOPS THE NORTHEAST
CARIBBEAN ISLANDS. ON SUNDAY-MONDAY THE LOW LEVEL WINDS ARE TO
THEN BACK TO THE NORTH...PUSHING THE WEAK FRONT SOUTH ACROSS
PUERTO RICO/VIRGIN ISLES TO THE NORTHEAST CARIBBEAN/LEEWARD
ISLANDS LATER IN THE DAY.

EARLY IN THE CYCLE...THE INFLOW OF MOISTURE AND MID LEVEL ENERGY
WILL ENHANCE SEA BREEZE CONVERGENCE OVER NORTHWEST PORTIONS OF
PUERTO RICO THIS AFTERNOON...TO RESULT IN MODERATE RAINFALL
AMOUNTS. LIGHT/LOCALLY MODERATE CONVECTION IS ALSO EXPECTED TO THE
EAST OF ARECIBO INTO WESTERN PORTIONS OF THE SAN JUAN METRO AREA.
AS SHALLOW MOISTURE LINGERS...A SECOND ROUND OF WEAKER CONVECTION
IS EXPECTED ACROSS NORTHERN PUERTO RICO ON FRIDAY. GLOBAL
MODELS...HOWEVER...CONTINUE TO DIVERGE ON THE IMPACT THE FRONT IS
TO HAVE DURING THE WEEKEND. ALTHOUGH THE EUROPEAN MODELS ARE NOW
STARTING TO EMBRACE THE POSSIBILITY OF CONVECTION BUILDING ACROSS
THE FORECAST AREA...THEY FAVOR A LATER ONSET THAN WHAT THE GFS
SUGGESTS...WITH THE GFS SHOWING MOST ACTIVE ON SATURDAY WHILE BOTH
EUROPEAN MODELS HAVE THE ACTIVITY ON SUNDAY. EXCEPT FOR MINOR
TIMING CORRECTIONS...THE GFS HAS BEEN FAIRLY CONSISTENT WITH ITS
FORECAST. THUS...ITS SOLUTION IS FAVORED OVER THE EUROPEAN MODELS.

DAVISON...WPC (USA)
GALVEZ...WPC (USA)