TROPICAL DISCUSSION - INTERNATIONAL DESKS NWS WEATHER PREDICTION CENTER COLLEGE PARK MD 822 AM EDT THU MAR 28 2024 PRELIMINARY DISCUSSION FOR PUERTO RICO AND THE USVI MAR 28/12UTC: DRY AIR MOVING IN FROM THE NORTH WILL PREVAIL OVER THE LOCAL ISLANDS THROUGH FRIDAY AFTERNOON...ALLOWING FAIR WEATHER TO PREVAIL THROUGH FRIDAY. A COLD FRONT IS EXPECTED TO REACH HISPANIOLA BY FRIDAY EVENING...AS IT MOVES EAST...THEN REACHING PR BY SATURDAY EVENING. THIS WILL CAUSE THE AVAILABLE MOISTURE TO INCREASE RAPIDLY FROM FRIDAY EVENING INTO SATURDAY OVER THE LOCAL ISLANDS...WITH MOISTURE PEAKING ON SATURDAY AFTERNOON AND EVENING. THE INCREASE IN MOISTURE AND APPROACHING COLD FRONT WILL CAUSE A SIGNIFICANT INCREASE IN THE CHANCES OF RAINFALL THIS WEEKEND. THE DRY AIR MOVING IN TODAY INTO FRIDAY WILL KEEP PRECIPITABLE WATER VALUES BELOW NORMAL THROUGH FRIDAY AFTERNOON...WITH VALUES BETWEEN 0.7 AND 1.0 INCHES. STARTING LATE FRIDAY INTO SATURDAY...PRECIPITABLE WATER WILL INCREASE RAPIDLY...AS THE COLD FRONT APPROACHES PR. THE LATEST GUIDANCE CONTINUES TO SUGGEST ABOVE NORMAL MOISTURE FOR SATURDAY AFTERNOON AND EVENING...WITH PRECIPITABLE WATER VALUES PEAKING NEAR 1.6 INCHES. THE MID AND UPPER LEVELS WILL HAVE A HIGH PRESSURE DOMINATING THE LOCAL ISLANDS THROUGH THE WEEKEND. A MID TO UPPER LEVEL LOW WILL MEANDER OVER THE WEST CENTRAL TROPICAL ATLANTIC THROUGH FRIDAY. AN UPPER LEVEL TROUGH WILL APPROACH THE NORTH CENTRAL CARIBBEAN THIS WEEKEND...WITH ITS AXIS OVER HISPANIOLA BY SUNDAY AFTERNOON. THE LATEST GUIDANCE ALSO SHOWS A STRENGTHENING UPPER LEVEL JET OVER PR/USVI OVERNIGHT FROM SUNDAY INTO MONDAY...WITH WINDS NEAR 90KT. THE MID LEVELS COULD ALSO HAVE A WEAK TROUGH MOVING INTO THE CARIBBEAN IN THE WEEKEND WITH MID LEVEL WINDS INCREASING AS WELL. THE TIMING OF THE MID LEVEL TROUGH AXIS COINCIDES WITH THE UPPER LEVELS...AS THE MID LEVEL TROUGH AXIS COULD BE OVER THE LOCAL ISLANDS OVERNIGHT SUNDAY INTO MONDAY. THE 5-DAY RAINFALL TOTAL FORECAST SUGGESTS NEAR 0.50 TO 0.75 INCHES FOR NORTH AND EASTERN PR. NEAR 0.25 TO 0.50 INCHES ARE FORECAST FOR THE USVI...VIEQUES AND CULEBRA. BETWEEN 0.10 AND 0.25 INCHES ARE FORECAST FOR CENTRAL TO WESTERN PR. ALAMO...WPC (USA)