326  
FXCA20 KWBC 061130  
PMDCA  
 
TROPICAL DISCUSSION - INTERNATIONAL DESKS  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
629 AM EST TUE FEB 06 2018  
 
PRELIMINARY DISCUSSION FOR PUERTO RICO AND THE USVI FROM FEB 06/06  
UTC: A DUAL BARRELED RIDGE NOW EXTENDS FROM MEXICO TO THE  
BAHAMAS/GREATER ANTILLES WHILE ANCHORING ON TWO CLOSED HIGHS. ONE  
HIGH CENTERS OVER THE YUCATAN WHILE THE OTHER LIES NEAR THE TURKS  
AND CAICOS/SOUTHEAST BAHAMAS. THE MID LEVEL RIDGE PATTERN SUSTAINS  
A TRADE WINDS CAP THAT IS INHIBITING DEEP CONVECTION OVER THE  
NORTHEAST CARIBBEAN. AT LOW LEVELS...REMNANTS OF A TUTT INDUCED  
PERTURBATION MOVED ACROSS THE FORECAST AREA...WITH TRAILING MOIST  
PLUME ENTERING THE MONA PASSAGE THIS MORNING. ON ITS WAKE...A  
DRYER AIR MASS IS ENTRAINING FROM THE EAST. ANOTHER TUTT INDUCED  
PERTURBATION IN THE EASTERLY TRADES IS INITIALIZED FARTHER TO THE  
EAST WITH AXIS ALONG 50W/52W.  
 
MID LEVEL HIGHS ARE TO COMBINE INTO A SINGLE CELL LATER IN THE  
WEEK...THAT IS FORECAST TO THEN MEANDER NORTH INTO THE WESTERN  
ATLANTIC. DURING THE WEEKEND THE CLOSED HIGH IS TO STALL TO THE  
SOUTH-SOUTHWEST OF BERMUDA...WHILE ASSOCIATED RIDGE STRENGTHENS  
ITS FOOTHOLD. DOWNSTREAM FROM THIS AXIS...A MEANDERING TUTT IS TO  
LIE OVER THE TROPICAL ATLANTIC/EAST OF THE ISLAND CHAIN THROUGH  
THE MEDIUM RANGE PERIOD. AS IT MEANDERS EAST OF THE ISLANDS THE  
TUTT IS TO CONTINUE INDUCING THE OCCASIONAL PERTURBATION IN THE  
EASTERLY TRADES. MEANWHILE...THE FORECAST AREA IS TO REMAIN ON THE  
CONVERGENT/SUBSIDENT SIDE OF THE MID LEVEL RIDGE-TROUGH. AT LOW  
LEVELS...BRISK EASTERLY TRADES ARE TO PREVAIL...WITH 850 HPA WINDS  
OF 20-25KT. EMBEDDED IN THIS FLOW...A TUTT INDUCED PERTURBATION  
REACHES THE LEEWARD ISLES ON THURSDAY MORNING... TAKING A BEELINE  
ACROSS THE VIRGIN ISLES-PUERTO RICO DURING THE DAY. A SECONDARY  
MID LEVEL VORTEX IS TO CLOSELY FOLLOW. THESE ARE TO ENHANCE LOW  
LEVEL MOISTURE CONVERGENCE...FAVORING SCATTERED CLOUDS WHILE  
TRIGGERING LIGHT CONVECTION. ON SATURDAY-SUNDAY THE GLOBAL MODELS  
AGREE ON TRADE WIND SURGE TO ENVELOP THE FORECAST AREA...WITH  
WINDS INCREASING TO 25-30KT.  
 
UNDER INFLUENCE OF PERSISTENT MID LEVEL CAP AND BRISK EASTERLY  
TRADES...EXPECTING A SEASONAL WEATHER PATTERN TO PREVAIL...WITH  
THE OCCASIONAL TRADE WIND SHOWER TO PESTER THE VIRGIN ISLES AND  
PUERTO RICO FROM TIME-TO-TIME WHILE ALSO FAVORING GENERATION OF  
STREAMERS ACROSS THE VIRGIN ISLES. MEASURABLE RAINFALL AMOUNTS ARE  
TO GENERALLY LIMIT TO EL YUNQUE RAINFOREST/LUQUILLO AREA. THIS  
PATTERN IS TO GENERALLY HOLD EXCEPT FOR THURSDAY-FRIDAY WHEN TUTT  
INDUCED PERTURBATION STREAMS ACROSS THE FORECAST AREA...RESULTING  
IN LOCALLY MODERATE RAINFALL AMOUNTS AS IT STREAMS ACROSS THE  
VIRGIN ISLES TO EASTERN PUERTO RICO.  
 
DAVISON/GALVEZ...WPC (USA)  
 

 
 
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