577  
FXCA20 KWBC 271106  
PMDCA  
 
TROPICAL DISCUSSION - INTERNATIONAL DESKS  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
706 AM EDT FRI OCT 27 2017  
 
PRELIMINARY DISCUSSION FOR PUERTO RICO AND THE USVI FROM OCT 27/06  
UTC: A TUTT REMAINS OVER THE EASTERN CARIBBEAN WHILE CENTERING ON  
A CLOSED LOW JUST NORTH OF CURACAO/ARUBA. POLAR TROUGH TO THE  
NORTH...MEANWHILE...IS STREAMING ACROSS THE WESTERN ATLANTIC/THE  
BAHAMAS. DURING THE DAY TODAY...THE POLAR TROUGH IS TO MIGRATE  
EAST WHILE YIELDING TO A BUILDING RIDGE. AS IT STREAMS NORTH OF  
THE FORECAST AREA IT IS TO BRIEFLY PHASE WITH THE TUTT TO THE  
SOUTH. THIS...IN-TURN...WILL LEAD TO RAPID EROSION OF TRADE WINDS  
CAP ENVELOPING THE FORECAST AREA EARLY THIS MORNING. THE BUILDING  
RIDGE WILL THEN STEER THE TUTT/TUTT LOW TO THE WEST...MEANDERING  
NORTH OF LA GUAJIRA PENINSULA LATER ON SATURDAY/EARLY SUNDAY  
MORNING...NEARING JAMAICA LATER ON MONDAY. AS THE TUTT MEANDERS  
AWAY...ENVIRONMENTAL CONDITIONS ARE TO REMAIN FAVORABLE AND  
CONDUCIVE FOR DEEP CONVECTION TO BUILD ACROSS THE ENTIRE FORECAST  
AREA THROUGH MONDAY EVENING. ON TUESDAY-WEDNESDAY...BUILDING RIDGE  
IS TO THEN STRENGTHEN THE TRADE WINDS CAP...FAVORING EROSION OF  
AVAILABLE MOISTURE WITH PWAT CONTENT FORECAST TO DECREASE TO AN  
INCH.  
 
AT LOW LEVELS...THE TUTT TO THE SOUTH SUSTAINS AN INDUCED TROUGH  
THAT IS MOVING ACROSS THE VIRGIN ISLES EARLY THIS MORNING. A PLUME  
OF DEEP TROPICAL MOISTURE ACCOMPANIES THIS WAVE...WITH SATELLITE  
DERIVED PWAT CONTENT OF AROUND TWO INCHES. NOTE THAT THIS WAVE  
ENTERED THE FORECAST AREA LATER THAN PREVIOUSLY ANTICIPATED...  
RESULTING IN A LATER ONSET OF THE ORGANIZED CONVECTION AND A LOWER  
THREAT OF AN MCS FORMING OVER THE VIRGIN ISLANDS.  
NEVERTHELESS...THIS IS TO SUSTAIN MODERATE TO HEAVY CONVECTION AS  
IT PULLS ACROSS THE VIRGIN ISLES TO EASTERN PUERTO RICO LATER THIS  
MORNING...AND HEAVY AFTERNOON CONVECTION ACROSS WESTERN INTERIOR  
PORTIONS OF PUERTO RICO/GUAJATACA BASIN. THE WAVE REACHES THE MONA  
PASSAGE LATER ON SATURDAY. ON ITS WAKE...THE LOW/MID LEVEL WINDS  
ARE TO VEER TO THE SOUTHEAST...WITH THE PREVAILING EASTERLY TRADES  
TO GRADUALLY RETURN BY MIDDAY ON MONDAY. IN RESPONSE...MOST ACTIVE  
CONVECTION IS TO THEN CLUSTER ACROSS NORTHWEST PORTIONS OF PUERTO  
RICO BETWEEN AGUADILLA/AGUADA AND BARCELONETA/MANATI.  
 
GUY...NMS (BELIZE)  
PECK...MS (JAMAICA)  
DAVISON/GALVEZ...WPC (USA)  

 
 
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