000 WTNT34 KNHC 230859 TCPAT4 BULLETIN TROPICAL STORM ISAAC ADVISORY NUMBER 9 NWS NATIONAL HURRICANE CENTER MIAMI FL AL092012 500 AM AST THU AUG 23 2012 ...AIR FORCE RESERVE RECONNAISSANCE AIRCRAFT FINDS ISAAC SLIGHTLY WEAKER AND FARTHER SOUTH... SUMMARY OF 500 AM AST...0900 UTC...INFORMATION ---------------------------------------------- LOCATION...15.3N 64.0W ABOUT 255 MI...410 KM SSE OF SAN JUAN PUERTO RICO ABOUT 370 MI...595 KM ESE OF ISLA SAONA DOMINICAN REPUBLIC MAXIMUM SUSTAINED WINDS...40 MPH...65 KM/H PRESENT MOVEMENT...W OR 270 DEGREES AT 12 MPH...19 KM/H MINIMUM CENTRAL PRESSURE...1004 MB...29.65 INCHES WATCHES AND WARNINGS -------------------- CHANGES WITH THIS ADVISORY... NONE. SUMMARY OF WATCHES AND WARNINGS IN EFFECT... A HURRICANE WARNING IS IN EFFECT FOR... * SOUTH COAST OF DOMINICAN REPUBLIC FROM ISLA SAONA WESTWARD TO THE HAITI-DOMINICAN REPUBLIC SOUTHERN BORDER * HAITI A TROPICAL STORM WARNING IS IN EFFECT FOR... * DOMINICA * 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 * NORTH COAST OF DOMINICAN REPUBLIC FROM THE HAITI-DOMINICAN REPUBLIC NORTHERN BORDER EASTWARD TO NORTH OF ISLA SAONA A TROPICAL STORM WATCH IS IN EFFECT FOR... * SOUTHEASTERN BAHAMAS INCLUDING THE ACKLINS...CROOKED ISLAND...LONG CAY...THE INAGUAS...MAYAGUANA...AND THE RAGGED ISLANDS AND THE TURKS AND CAICOS ISLANDS A HURRICANE WARNING MEANS THAT HURRICANE CONDITIONS ARE EXPECTED SOMEWHERE WITHIN THE WARNING AREA. PREPARATIONS TO PROTECT LIFE AND PROPERTY SHOULD BE RUSHED TO COMPLETION. A TROPICAL STORM WARNING MEANS THAT TROPICAL STORM CONDITIONS ARE EXPECTED SOMEWHERE WITHIN THE WARNING AREA WITHIN 36 HOURS. A TROPICAL STORM WATCH MEANS THAT TROPICAL STORM CONDITIONS ARE POSSIBLE WITHIN THE WATCH AREA...GENERALLY WITHIN 48 HOURS. INTERESTS IN CUBA...JAMAICA...AND ELSEWHERE IN THE BAHAMAS 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 500 AM AST...0900 UTC...THE CENTER OF TROPICAL STORM ISAAC HAS REFORMED NEAR LATITUDE 15.3 NORTH...LONGITUDE 64.0 WEST. ISAAC IS MOVING TOWARD THE WEST NEAR 12 MPH...19 KM/H. SOME ERRATIC MOTION TOWARD THE WEST-NORTHWEST TO NORTHWEST COULD OCCUR THIS MORNING... BUT A STEADY MOTION TOWARD THE WEST-NORTHWEST IS EXPECTED TO BEGIN BY THIS AFTERNOON OR TONIGHT AND CONTINUE INTO FRIDAY. ON THE FORECAST TRACK...THE CENTER OF ISAAC SHOULD PASS TO THE SOUTH OF THE VIRGIN ISLANDS AND PUERTO RICO TODAY...AND APPROACH THE DOMINICAN REPUBLIC TONIGHT AND FRIDAY. DATA FROM AN AIR FORCE RESERVE RECONNAISSANCE AIRCRAFT AND A NOAA BUOY INDICATE MAXIMUM SUSTAINED WINDS HAVE DECREASED TO NEAR 40 MPH...65 KM/H...WITH HIGHER GUSTS. HOWEVER...RE-STRENGTHENING IS FORECAST DURING THE NEXT 48 HOURS....AND ISAAC COULD STILL BECOME A HURRICANE ON FRIDAY BEFORE IT REACHES HISPANIOLA. TROPICAL-STORM-FORCE WINDS EXTEND OUTWARD UP TO 140 MILES...220 KM FROM THE CENTER. THE ESTIMATED MINIMUM CENTRAL PRESSURE BASED ON REPORTS FROM THE AIRCRAFT AND A NEARBY NOAA BUOY IS 1004 MB...29.65 INCHES. HAZARDS AFFECTING LAND ---------------------- WIND...TROPICAL STORM CONDITIONS SHOULD BEGIN TO SUBSIDE OVER THE LEEWARD ISLANDS LATER THIS MORNING. TROPICAL STORM CONDITIONS ARE EXPECTED OVER PUERTO RICO AND THE U.S. AND BRITISH VIRGIN ISLANDS TODAY. HURRICANE CONDITIONS ARE EXPECTED OVER PORTIONS OF THE DOMINICAN REPUBLIC BY TONIGHT OR EARLY FRIDAY...AND OVER PORTIONS OF HAITI ON FRIDAY. TROPICAL STORM CONDITIONS ARE POSSIBLE OVER THE SOUTHEASTERN BAHAMAS AND THE TURKS AND CAICOS ISLANDS BY LATE FRIDAY. RAINFALL...TOTAL RAIN ACCUMULATIONS OF 4 TO 8 INCHES ARE POSSIBLE OVER THE NORTHERN WINDWARD ISLANDS AND THE LEEWARD ISLANDS. TOTAL RAIN ACCUMULATIONS OF 2 TO 4 INCHES...WITH MAXIMUM AMOUNTS OF 10 INCHES OVER HIGHER TERRAIN...ARE POSSIBLE OVER PUERTO RICO AND THE VIRGIN ISLANDS. TOTAL RAINFALL ACCUMULATIONS OF 8 TO 12 INCHES... WITH MAXIMUM AMOUNTS OF 20 INCHES...ARE POSSIBLE OVER HISPANIOLA. THESE RAINS COULD CAUSE LIFE-THREATENING FLASH FLOODS AND MUD SLIDES. STORM SURGE...A STORM SURGE WILL RAISE WATER LEVELS BY AS MUCH AS 3 TO 5 FEET ABOVE NORMAL TIDE LEVELS IN AREAS OF ONSHORE WINDS ALONG THE COAST OF HISPANIOLA. 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 ISLANDS...LEEWARD ISLANDS...VIRGIN ISLANDS...AND PUERTO RICO DURING THE NEXT COUPLE OF DAYS. PLEASE CONSULT PRODUCTS FROM YOUR LOCAL WEATHER OFFICE FOR MORE INFORMATION. NEXT ADVISORY ------------- NEXT INTERMEDIATE ADVISORY...800 AM AST. NEXT COMPLETE ADVISORY...1100 AM AST. $$ FORECASTER STEWART