000 WTNT34 KNHC 220248 TCPAT4 BULLETIN TROPICAL STORM ISAAC ADVISORY NUMBER 4 NWS NATIONAL HURRICANE CENTER MIAMI FL AL092012 1100 PM AST TUE AUG 21 2012 ...ISAAC CONTINUES WESTWARD TOWARD THE LEEWARD ISLANDS...TROPICAL STORM WARNINGS ISSUED FOR PUERTO RICO AND THE VIRGIN ISLANDS... SUMMARY OF 1100 PM AST...0300 UTC...INFORMATION ----------------------------------------------- LOCATION...15.6N 55.6W ABOUT 390 MI...625 KM E OF GUADELOUPE MAXIMUM SUSTAINED WINDS...40 MPH...65 KM/H PRESENT MOVEMENT...W OR 275 DEGREES AT 18 MPH...30 KM/H MINIMUM CENTRAL PRESSURE...1006 MB...29.71 INCHES WATCHES AND WARNINGS -------------------- CHANGES WITH THIS ADVISORY... THE GOVERNMENT OF ANTIGUA AND BARBUDA HAS CHANGED THE TROPICAL STORM WATCH FOR THE BRITISH VIRGIN ISLANDS TO A TROPICAL STORM WARNING. THE TROPICAL STORM WATCH FOR PUERTO RICO...VIEQUES...CULEBRA...AND THE U.S. VIRGIN ISLANDS HAS BEEN CHANGED TO A TROPICAL STORM WARNING. A HURRICANE WATCH HAS BEEN ISSUED FOR PUERTO RICO...VIEQUES... CULEBRA...AND THE U.S. VIRGIN ISLANDS. SUMMARY OF WATCHES AND WARNINGS IN EFFECT... A TROPICAL STORM WARNING IS IN EFFECT FOR... * MARTINIQUE * DOMINICA * GUADELOUPE AND THE SURROUNDING ISLANDS...AND ST. MARTIN * ST. KITTS...NEVIS...ANTIGUA...BARBUDA...MONTSERRAT...AND ANGUILLA * SABA...ST. EUSTATIUS...AND ST. MAARTEN * BRITISH VIRGIN ISLANDS * PUERTO RICO...VIEQUES...CULEBRA...AND THE U.S. VIRGIN ISLANDS A HURRICANE WATCH IS IN EFFECT FOR... * PUERTO RICO...VIEQUES...CULEBRA...AND THE U.S. VIRGIN ISLANDS A HURRICANE WATCH MEANS THAT HURRICANE CONDITIONS ARE POSSIBLE WITHIN THE WATCH AREA. A WATCH IS TYPICALLY ISSUED 48 HOURS BEFORE THE ANTICIPATED FIRST OCCURRENCE OF TROPICAL-STORM-FORCE WINDS...CONDITIONS THAT MAKE OUTSIDE PREPARATIONS DIFFICULT OR DANGEROUS. A TROPICAL STORM WARNING MEANS THAT TROPICAL STORM CONDITIONS ARE EXPECTED SOMEWHERE WITHIN THE WARNING AREA WITHIN 36 HOURS. INTERESTS IN HISPANIOLA AND CUBA SHOULD MONITOR THE PROGRESS OF ISAAC. FOR STORM INFORMATION SPECIFIC TO YOUR AREA IN THE UNITED STATES...INCLUDING POSSIBLE INLAND WATCHES AND WARNINGS...PLEASE MONITOR PRODUCTS ISSUED BY YOUR LOCAL NATIONAL WEATHER SERVICE FORECAST OFFICE. FOR STORM INFORMATION SPECIFIC TO YOUR AREA OUTSIDE THE UNITED STATES...PLEASE MONITOR PRODUCTS ISSUED BY YOUR NATIONAL METEOROLOGICAL SERVICE. DISCUSSION AND 48-HOUR OUTLOOK ------------------------------ AT 1100 PM AST...0300 UTC...THE CENTER OF TROPICAL STORM ISAAC WAS LOCATED NEAR LATITUDE 15.6 NORTH...LONGITUDE 55.6 WEST. ISAAC IS MOVING TOWARD THE WEST NEAR 18 MPH...30 KM/H...AND THIS GENERAL MOTION IS EXPECTED TO CONTINUE FOR THE NEXT COUPLE OF DAYS. ON THE FORECAST TRACK...THE CENTER OF ISAAC SHOULD MOVE THROUGH THE LEEWARD ISLANDS WEDNESDAY EVENING...AND MOVE OVER THE NORTHEASTERN CARIBBEAN SEA ON THURSDAY. MAXIMUM SUSTAINED WINDS ARE NEAR 40 MPH...65 KM/H...WITH HIGHER GUSTS. STRENGTHENING IS FORECAST DURING THE NEXT 48 HOURS...AND ISAAC COULD BECOME A HURRICANE BY THURSDAY. TROPICAL STORM FORCE WINDS EXTEND OUTWARD UP TO 45 MILES...75 KM FROM THE CENTER. ESTIMATED MINIMUM CENTRAL PRESSURE IS 1006 MB...29.71 INCHES. HAZARDS AFFECTING LAND ---------------------- WIND...TROPICAL STORM CONDITIONS ARE EXPECTED TO REACH THE LEEWARD ISLANDS BY WEDNESDAY AFTERNOON OR EVENING...MAKING OUTSIDE PREPARATIONS DIFFICULT OR DANGEROUS. TROPICAL STORM CONDITIONS ARE EXPECTED OVER PUERTO RICO AND THE U.S. AND BRITISH VIRGIN ISLANDS ON THURSDAY. HURRICANE CONDITIONS ARE POSSIBLE OVER PUERTO RICO AND THE U.S. VIRGIN ISLANDS ON THURSDAY. RAINFALL...TOTAL RAIN ACCUMULATIONS OF 4 TO 8 INCHES ARE POSSIBLE OVER THE NORTHERN WINDWARD ISLANDS AND THE LEEWARD ISLANDS. TOTAL RAIN ACCUMULATIONS OF 1 TO 3 INCHES WITH MAXIMUM AMOUNTS OF 6 INCHES ARE POSSIBLE OVER PUERTO RICO AND THE VIRGIN ISLANDS. STORM SURGE...A STORM SURGE WILL RAISE WATER LEVELS BY AS MUCH AS 1 TO 3 FEET ABOVE NORMAL TIDE LEVELS IN THE NORTHERN LEEWARD ISLANDS...PUERTO RICO...AND THE U.S. AND BRITISH VIRGIN ISLANDS. NEAR THE COAST...THE SURGE WILL BE ACCOMPANIED BY DANGEROUS WAVES. SURF...DANGEROUS SURF AND RIP CURRENT CONDITIONS WILL AFFECT THE WINDWARD AND LEEWARD ISLANDS DURING THE NEXT COUPLE OF DAYS. PLEASE CONSULT PRODUCTS FROM YOUR LOCAL WEATHER OFFICE FOR MORE INFORMATION. NEXT ADVISORY ------------- NEXT INTERMEDIATE ADVISORY...200 AM AST. NEXT COMPLETE ADVISORY...500 AM AST. $$ FORECASTER PASCH