341  
FXCA20 KWBC 281053  
PMDCA  
 
TROPICAL DISCUSSION - INTERNATIONAL DESKS  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
652 AM EDT SAT OCT 28 2017  
 
PRELIMINARY DISCUSSION FOR PUERTO RICO AND THE USVI FROM OCT 28/06  
UTC: TUTT LOW CENTERED NEAR 16N 68W EARLY THIS MORNING. THE LOW  
ANCHORS A SHORT WAVE TROUGH ACROSS THE EASTERN CARIBBEAN. THIS IS  
FORECAST TO REMAIN NEARLY STATIONARY THROUGH MIDDAY ON SUNDAY.  
LATER IN THE DAY IT WILL START A WESTWARD MIGRATION AS A MID/UPPER  
LEVEL RIDGE BUILDS TO THE NORTH OF THE OF THE ISLANDS...NEARING  
JAMAICA LATER ON MONDAY/EARLY TUESDAY MORNING. AS THE TROUGH PULLS  
AWAY...THE BUILDING RIDGE IS TO THEN ESTABLISH A VERY STRONG TRADE  
WINDS CAP ACROSS THE FORECAST AREA ON TUESDAY.  
 
THE UPPER LEVEL FEATURE HAS A FAIRLY STRONG LOW/MID LEVEL  
REFLECTION...SUSTAINING AN INDUCED TROUGH THAT IS MOVING ACROSS  
WESTERN PUERTO RICO TO THE MONA PASSAGE EARLY THIS MORNING. IN  
RESPONSE TO THIS WAVE... THE LOW/MID LEVEL STEERING FLOW IS  
VEERING TO THE SOUTHEAST. THIS WAVE...IN INTERACTION WITH UPPER  
LEVEL TROUGH...IS ENHANCING MOISTURE TRANSPORT ACROSS THE  
NORTHEAST CARIBBEAN ISLES...WITH A PLUME OF DEEP TROPICAL MOISTURE  
POOLING ACROSS THE ENTIRE FORECAST AREA. ON THE WAKE OF THIS  
WAVE...THE WINDS ARE FORECAST TO RETAIN A SOUTH-SOUTHEASTERLY  
COMPONENT THROUGH AT LEAST MONDAY MORNING. THE PREVAILING  
EASTERLIES ARE EXPECTED TO RETURN DURING THE LATE  
AFTERNOON/EVENING HOURS ON MONDAY. MEANWHILE...THE SOUTH-SOUTHEAST  
FLOW IS TO RESULT IN HOT AND STUFFY WEATHER CONDITIONS OVER  
NORTHERN PORTIONS OF THE ISLAND DUE TO ADIABATIC  
COMPRESSION...WITH ABOVE NORMAL TEMPERATURES EXPECTED THROUGHOUT  
THE WEEKEND. AS THE EASTERLIES RETURN EARLY NEXT WEEK...SEASONAL  
TEMPERATURES WILL RETURN TO THE FORECAST AREA.  
 
AS THE PATTERN SLOWLY EVOLVES OVER THE NEXT COUPLE OF DAYS...  
EXPECTING LIGHT TO MODERATE CONVECTION TO AFFECT SAINT CROIX AND  
EASTERN PORTIONS OF PUERTO RICO/SAN JUAN METRO AREA IN A DIURNAL  
PATTERN. LESSER AMOUNTS ARE FORECAST ACROSS THE NORTHERN VIRGIN  
ISLES. THE MOST INTENSE CONVECTION IS TO CLUSTER ACROSS NORTHWEST  
PORTIONS OF PUERTO RICO IN MIDAFTERNOON CONVECTION. ON MONDAY...AS  
THE PREVAILING EASTERLY TRADES RETURN TO THE FORECAST  
AREA...EXPECTING SLIGHT INCREASE ACROSS NORTHEAST PUERTO RICO/EL  
YUNQUE RAINFOREST...WITH MODERATE CONVECTION CLUSTERING OVER  
WESTERN INTERIOR PORTIONS OF PUERTO RICO. STRENGTHENING TRADE  
WINDS CAP WILL THEN RESULT IN LARGE SCALE EROSION OF AVAILABLE  
MOISTURE AND A LULL IN ACTIVITY. AS PWAT CONTENT DROPS TO 1.0-1.25  
INCHES...MEASURABLE AMOUNTS WILL CONFINE TO WESTERN INTERIOR  
PORTIONS OF PUERTO RICO.  
 
GUY...NMS (BELIZE)  
PECK...MS (JAMAICA)  
DAVISON...WPC (USA)  

 
 
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