707  
FXCA20 KWBC 021100  
PMDCA  
 
TROPICAL DISCUSSION - INTERNATIONAL DESKS  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
659 AM EDT THU NOV 02 2017  
 
PRELIMINARY DISCUSSION FOR PUERTO RICO AND THE USVI FROM NOV 02/06  
UTC: A MEANDERING MID/UPPER LEVEL HIGH OVER THE CAYMAN ISLES  
ANCHORS A RIDGE ACROSS THE CARIBBEAN BASIN-CENTRAL AMERICA/MEXICO.  
THIS FAVORS A STRONG TRADE WINDS CAP ACROSS THE NORTHEAST  
CARIBBEAN. AT LOW LEVELS...A TUTT EAST OF THE ISLANDS INDUCED A  
PERTURBATION IN THE EASTERLY TRADES THAT MOVED ACROSS THE VIRGIN  
ISLES/EASTERN PUERTO RICO EARLY THIS MORNING. UNABLE TO BREACH THE  
STRONG TRADE WINDS CAP...THE WAVE ONLY TRIGGERED WIDELY ISOLATED  
SHALLOW CONVECTION.  
 
SUCCESSIVE POLAR PERTURBATIONS STREAMING ACROSS THE USA-WESTERN  
ATLANTIC WILL PRESS AGAINST THIS RIDGE. AS THEY STREAM ACROSS THE  
WESTERN ATLANTIC...THESE WILL THEN SUSTAIN THE GRADUAL EROSION OF  
THE MID/UPPER LEVEL RIDGE PATTERN DURING THE WEEKEND. ALTHOUGH THE  
RIDGE WEAKENS OVER THE BASIN...OVER MEXICO IT TENDS TO BUILD.  
THIS...IN-TURN...WILL THEN INDUCED THE SOUTHWARD AMPLIFICATION OF  
A LONG WAVE TROUGH ACROSS THE WESTERN/CENTRAL CARIBBEAN...WHILE  
OVER THE EASTERN CARIBBEAN A CELL OF THE SUBEQUATORIAL RIDGE IS TO  
ESTABLISH. AS THE PATTERN EVOLVES...THE STRONG TRADE WINDS CAP  
GRADUALLY RELAXES ITS FOOTHOLD ACROSS THE FORECAST AREA BY  
MIDMORNING ON SATURDAY. AT LOW LEVELS...DEEP LAYER EASTERLY TRADES  
ARE TO PREVAIL THROUGH SATURDAY MORNING. WINDS ARE TO THEN VEER TO  
THE SOUTHEAST AS ANOTHER TUTT INDUCED PERTURBATION MOVES ACROSS  
THE EASTERN CARIBBEAN. THE SOUTHEASTERLY TRADES ARE TO THEN  
PERSIST THROUGH EARLY NEXT WEEK. THIS IS TO THEN ADVECT A PLUME OF  
DEEP TROPICAL MOISTURE ACROSS THE LESSER ANTILLES INTO THE  
NORTHEAST CARIBBEAN...WITH PWAT CONTENT INCREASING TO 1.50 INCHES  
EARLY ON SATURDAY AND AROUND 2.0 INCHES ON MONDAY. THIS WILL FEED  
AN INCREASE IN CONVECTION ACROSS THE FORECAST AREA...WITH MOST  
INTENSE EXPECTED ALONG THE NORTH COAST OF PUERTO RICO AND WESTERN  
INTERIOR PORTIONS OF THE ISLAND. ACROSS THE VIRGIN ISLES EXPECTING  
LIGHT TO MODERATE RAINFALL AMOUNTS AS ENHANCED BY BRISK  
SOUTHEASTERLY FLOW.  
 
GUY...NMS (BELIZE)  
PECK...MS (JAMAICA)  
DAVISON...WPC (USA)  
 

 
 
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