395  
FXCA20 KWBC 051104  
PMDCA  
 
TROPICAL DISCUSSION - INTERNATIONAL DESKS  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
604 AM EST SUN NOV 05 2017  
 
PRELIMINARY DISCUSSION FOR PUERTO RICO AND THE USVI FROM NOV 04/06  
UTC: UNDER INFLUENCE OF AN UPPER LEVEL RIDGE OVER MEXICO/THE  
USA...A LONG WAVE TROUGH EXTENDS FROM THE WESTERN  
ATLANTIC...ACROSS WESTERN CUBA TO THE GULF OF HONDURAS/GUATEMALA.  
THROUGH TUESDAY EVENING THE TROUGH IS TO RELOCATE TO THE  
TURKS/SOUTHEAST BAHAMAS...WHILE TRAILING ACROSS JAMAICA TO THE  
CENTRAL CARIBBEAN. AT 250 HPA A 70-90KT JET MAXIMA FLANKS THE  
EASTERN FRINGES OF THIS TROUGH. THIS FAVORS AN UPPER DIVERGENT  
PATTERN ACROSS THE CENTRAL CARIBBEAN-GREATER ANTILLES. ALTHOUGH  
THE TROUGH TENDS TO WEAKEN AS THE WEEK WEARS ON...AN UPPER LEVEL  
DIVERGENT PATTERN IS TO PERSIST THROUGH THE END OF THE WORKWEEK.  
AS A RESULT...ENVIRONMENTAL CONDITIONS ARE TO REMAIN FAVORABLE FOR  
DEEP CONVECTION TO DEVELOP ACROSS THE ENTIRE FORECAST AREA. AT 500  
HPA THE TROUGH FOLLOWS A SIMILAR EVOLUTION...STALLING OVER THE  
TURKS/NORTH OF HISPANIOLA LATER ON TUESDAY/EARLY WEDNESDAY  
MORNING.  
 
AT LOW LEVELS...REMNANTS OF A TUTT INDUCED PERTURBATION IN THE  
EASTERLY TRADES PULLS ACROSS 70W EARLY THIS MORNING. ON ITS WAKE A  
MOIST SOUTHEASTERLY FLOW IS TO ESTABLISH ACROSS THE EASTERN  
CARIBBEAN. THIS WILL ENHANCE THE TRANSPORT OF DEEP TROPICAL  
MOISTURE ACROSS THE FORECAST AREA...WITH PWAT CONTENT GRADUALLY  
INCREASING TO 2.0 INCHES ON TUESDAY. AN EAST TO SOUTHEAST EASTERLY  
FLOW IS TO GENERALLY PERSIST DURING THE NEXT FEW DAYS. AT 700  
HPA...A MID LEVEL LOW FORMS TO THE NORTH OF THE DOMINICAN REPUBLIC  
EARLY IN THE WEEK...TO SUSTAIN A SOUTH-SOUTHWESTERLY FLOW ACROSS  
THE FORECAST AREA. THE ENSUING LOW LOW/MID LEVEL SHEAR WILL LIKELY  
RESULT IN LONGER LASTING HEAVY RAINFALL PRODUCING THUNDERSTORMS  
ACROSS PUERTO RICO. IN THIS PATTERN THE GLOBAL MODEL GUIDANCE  
AGREE ON RISK OF MODERATE...LOCALLY HEAVY... CONVECTION TO AFFECT  
THE NORTHEAST CARIBBEAN ISLES THROUGH THE SHORT RANGE PERIOD. THE  
ECMWF GDI GUIDANCE IN PARTICULAR SHOWS A HIGHER POTENTIAL THAN THE  
GFS FOR ORGANIZED DEEP CONVECTION ACROSS THE FORECAST AREA ON  
TUESDAY-WEDNESDAY. THE QPF GUIDANCE FOR THE NEXT FEW DAYS TAKES  
INTO ACCOUNT THIS DIFFERENCES. AS A RESULT...EXPECTING MOST  
INTENSE CONVECTION TO CLUSTER ACROSS NORTHERN PORTIONS OF PUERTO  
RICO.  
 
GUY...NMS (BELIZE)  
PECK...MS (JAMAICA)  
RIVAS...SENAMHI (PERU)  
DAVISON...WPC (USA)  
 

 
 
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