326  
FXCA20 KWBC 171246  
PMDCA  
 
TROPICAL DISCUSSION - INTERNATIONAL DESKS  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
845 AM EDT FRI MAR 17 2023  
 
PRELIMINARY DISCUSSION FOR PUERTO RICO AND THE USVI FROM MAR  
17/12UTC: TODAY DRYER AIR MOVING IN AFTER A SURFACE COLD FRONT  
PASSED OVER THE ISLANDS OVERNIGHT MOVING SOUTHWARD. IN THE  
MID-LEVELS A TRADE WIND CAP INVERSION IS FOUND AT AROUND THE  
700-750 HPA LEVELS. ADDITIONALLY WINDS ARE COMING FROM THE  
NORTHEAST AT AROUND 15-20KT WHICH WILL GIVE WAY TO INTERMITTENT  
SHOWERS THROUGHOUT THE DAY. THE MAJORITY OF THE ACCUMULATIONS ARE  
EXPECTED IN THE LUQUILLO MOUNTAIN RANGE AND THE CORDILLERA CENTRAL  
WITH AMOUNTS BETWEEN 0.2-0.4 INCHES. USVI MAY SEE SIMILAR  
ACCUMULATIONS.  
 
ON SATURDAY...IT IS EXPECTED TO BE THE DRIEST DAY OF THE FORECAST  
PERIOD AS THE TRADE WINDS SHIFT TO EASTERLIES AND DRY AIR AND  
PRECIPITABLE WATER VALUES LESS THAN 1 INCH ARE FORECAST OVER MOST  
OF THE ISLANDS. PRECIPITATION AMOUNTS LESS THAN 0.15 INCHES ARE  
EXPECTED TO THE NORTHEAST OF PUERTO RICO...WITH OTHER AREAS OF  
THE ISLAND FORECAST FOR LESS THAN 0.1 INCHES OF RAIN. ON  
SUNDAY...MOIST PLUMES FROM THE REMNANTS OF THE PREVIOUS SURFACE  
FRONT ARE MAKING THEIR FROM THE EAST AS TRADE WINDS BEGIN PICKING  
UP TO ABOUT 20-25KT. THE LARGEST AMOUNTS OF PRECIPITATION ARE  
EXPECTED AROUND VIEQUES WITH A MAXIMA BETWEEN 0.25-0.4  
INCHES...AND THE EASTERN PORTION OF PUERTO RICO SEEING AMOUNTS  
UNDER 0.25 INCHES. SIMILAR AMOUNTS ARE EXPECTED IN THE REST OF THE  
FORECAST AREA. FOR MONDAY AND TUESDAY...THE AVAILABLE MOISTURE  
WILL BE ABOVE NORMAL. THE EASTERLY TRADES WILL TRANSPORT A  
LOW-LEVEL PERTURBATION WITH DEEPER MOISTURE...UNTIL IT MEETS A  
COLD FRONT OVER THE BAHAMAS AND THEN MOVES TO THE NORTH NORTHEAST.  
THIS WILL CAUSE THE CHANCES OF RAINFALL TO INCREASE ACROSS PR/USVI  
WITH AN ADVECTIVE PATTERN CAUSING PERSISTENT RAINFALL OVER EASTERN  
PR AND THE USVI...WHILE AFTERNOON CONVECTION WILL OCCUR ACROSS  
WESTERN PR AS THE DIURNAL HEATING COMBINES WITH THE LOCAL EFFECTS  
AND AVAILABLE MOISTURE. ALTHOUGH THERE IS SOME UNCERTAINTY AND  
DISCREPANCY AMONG THE MODEL GUIDANCE...THE PERSISTENT RAINFALL  
THAT IS FORECAST...COULD SURPASS A HALF AN INCH TO THREE QUARTERS  
OF AN INCH OF RAIN ACROSS NORTHEASTERN PR...WHILE SIMILAR AMOUNTS  
ARE POSSIBLE ACROSS WEST AND NORTHWESTERN PR ACROSS ISOLATED AREAS  
WITH THE EXPECTED AFTERNOON CONVECTION. THE HIGHER THAN NORMAL  
MOISTURE WILL LINGER INTO LATE TUESDAY AFTERNOON OR EARLY EVENING.  
MUCH DRIER AIR IS EXPECTED TO MOVE IN BY EARLY WEDNESDAY MORNING.  
 
ACOSTA/ALAMO...WPC (USA)  

 
 
CLICK HERE TO GO TO PREVIOUS BULLETINS.

The Nexlab HPC Page Main Text Page