531  
FXCA20 KWBC 061125  
PMDCA  
 
TROPICAL DISCUSSION - INTERNATIONAL DESKS  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
624 AM EST MON NOV 06 2017  
 
PRELIMINARY DISCUSSION FOR PUERTO RICO AND THE USVI FROM NOV 06/06  
UTC: A MID/UPPER LEVEL TROUGH EXTENDS TO THE SOUTHWEST ACROSS THE  
NORTHWEST BAHAMAS-CENTRAL CUBA TO THE NORTHWEST CARIBBEAN. THROUGH  
TUESDAY EVENING THE TROUGH IS TO RELOCATE TO THE SOUTHEAST  
BAHAMAS-EASTERN CUBA-CENTRAL CARIBBEAN...WHERE IT IS TO STALL  
WHILE PRESSING AGAINST A CELL OF THE SUBEQUATORIAL RIDGE TO THE  
EAST. THE TROUGH IS THEN FORECAST TO GRADUALLY WEAKEN AS SHORT  
WAVE ENERGY LIFTS OVER THE RIDGE...WITH AXIS TO NEARLY DISSIPATE  
LATER ON THURSDAY/EARLY FRIDAY MORNING. THE NORTHEAST CARIBBEAN  
ISLES LIE ON THE DIVERGENT SIDE OF THE UPPER LEVEL FEATURE...A  
PATTERN THAT IS TO HOLD THROUGH THE END OF THE WEEK.  
 
AT LOW LEVELS...UNDER INFLUENCE OF A RIDGE TO THE NORTH AND AN  
INVERTED TROUGH TO THE WEST...A DEEP LAYER SOUTHEASTERLY FLOW  
DOMINATES THE EASTERN CARIBBEAN. THIS IS ADVECTING A PLUME OF  
TROPICAL MOISTURE ACROSS THE FORECAST AREA...WITH PWAT CONTENT OF  
2 INCHES. AS THE UPPER TROUGH PHASES WITH THE LOW LEVEL  
PERTURBATION THE LATTER IS TO STRENGTHEN...TO HELP SUSTAIN THE  
MOIST INFLOW DURING THE NEXT FEW DAYS. THIS IS TO FEED CONVECTIVE  
DEVELOPMENT...WITH GLOBAL MODELS AGREEING ON BEST MOISTURE  
CONVERGENCE TO TAKE PLACE JUST NORTH OF THE FORECAST AREA...WITH  
THUNDERSTORMS CLUSTERING ALONG 20N-22N. IN A SOUTHEASTERLY  
STEERING FLOW...MOST ACTIVE CONVECTION IS TO CLUSTER ACROSS  
NORTHWEST PUERTO RICO IN A DIURNAL PATTERN. THIS WILL SUSTAIN  
RAINFALL AMOUNTS OF 1-3 INCHES PER DAY. LESSER AMOUNTS ARE  
EXPECTED ACROSS THE SAN JUAN METRO AREA AND THE NORTHERN VIRGIN  
ISLES...WHILE ACROSS SAINT CROIX THE DAILY MAXIMA IS TO PEAK AT  
1-2 INCHES.  
 
GUY...NMS (BELIZE)  
PECK...MS (JAMAICA)  
RIVAS...SENAMHI (PERU)  
DAVISON...WPC (USA)  
 

 
 
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