000 WTNT34 KNHC 291858 TCPAT4 BULLETIN TROPICAL STORM ISAAC INTERMEDIATE ADVISORY NUMBER 34B NWS NATIONAL HURRICANE CENTER MIAMI FL AL092012 200 PM CDT WED AUG 29 2012 ...ISAAC WEAKENS TO A TROPICAL STORM...LIFE-THREATENING HAZARDS FROM STORM SURGE AND INLAND FLOODING ARE STILL OCCURRING... SUMMARY OF 200 PM CDT...1900 UTC...INFORMATION ---------------------------------------------- LOCATION...29.8N 90.9W ABOUT 50 MI...80 KM WSW OF NEW ORLEANS LOUISIANA ABOUT 55 MI...90 KM SSE OF BATON ROUGE LOUISIANA MAXIMUM SUSTAINED WINDS...70 MPH...110 KM/H PRESENT MOVEMENT...NW OR 310 DEGREES AT 6 MPH...9 KM/H MINIMUM CENTRAL PRESSURE...974 MB...28.76 INCHES WATCHES AND WARNINGS -------------------- CHANGES WITH THIS ADVISORY... THE HURRICANE WARNING AND THE HURRICANE WATCH HAVE BEEN DISCONTINUED...AND THE TROPICAL STORM WARNING HAS BEEN ADJUSTED. SUMMARY OF WATCHES AND WARNINGS IN EFFECT... A TROPICAL STORM WARNING IS IN EFFECT FOR... * CAMERON LOUISIANA TO THE ALABAMA-FLORIDA BORDER FOR STORM INFORMATION SPECIFIC TO YOUR AREA...PLEASE MONITOR PRODUCTS ISSUED BY YOUR LOCAL NATIONAL WEATHER SERVICE FORECAST OFFICE. DISCUSSION AND 48-HOUR OUTLOOK ------------------------------ AT 200 PM CDT...1900 UTC...THE CENTER OF TROPICAL STORM ISAAC WAS LOCATED BY NOAA DOPPLER WEATHER RADAR NEAR LATITUDE 29.8 NORTH... LONGITUDE 90.9 WEST. ISAAC IS MOVING TOWARD THE NORTHWEST NEAR 6 MPH...9 KM/H. THIS GENERAL MOTION IS EXPECTED TO CONTINUE THROUGH TONIGHT...FOLLOWED BY A TURN TOWARD THE NORTH-NORTHWEST BY THURSDAY NIGHT OR EARLY FRIDAY. ON THE FORECAST TRACK...THE CENTER OF ISAAC WILL MOVE FARTHER INLAND OVER LOUISIANA TODAY AND TOMORROW...AND MOVE OVER SOUTHERN ARKANSAS BY EARLY FRIDAY. MAXIMUM SUSTAINED WINDS ARE NEAR 70 MPH...110 KM/H...WITH HIGHER GUSTS. GRADUAL WEAKENING IS FORECAST DURING THE NEXT 48 HOURS AS ISAAC CONTINUES TO MOVE FARTHER INLAND. TROPICAL-STORM-FORCE WINDS EXTEND OUTWARD UP TO 175 MILES...280 KM FROM THE CENTER. A GUST TO 70 MPH WAS RECENTLY REPORTED AT GULFPORT MISSISSIPPI. THE ESTIMATED MINIMUM CENTRAL PRESSURE BASED ON NEARBY SURFACE OBSERVATIONS IS 974 MB...28.76 INCHES. HAZARDS AFFECTING LAND ---------------------- EVEN THOUGH ISAAC IS NO LONGER A HURRICANE...LIFE-THREATENING HAZARDS FROM STORM SURGE AND INLAND FLOODING ARE STILL OCCURRING. STORM SURGE...THE COMBINATION OF A STORM SURGE AND THE TIDE WILL CAUSE NORMALLY DRY AREAS NEAR THE COAST TO BE FLOODED BY RISING WATERS. THE WATER COULD REACH THE FOLLOWING DEPTHS ABOVE GROUND IF THE PEAK SURGE OCCURS AT THE TIME OF HIGH TIDE... * MISSISSIPPI AND SOUTHEASTERN LOUISIANA...6 TO 12 FT * ALABAMA...3 TO 6 FT * SOUTH-CENTRAL LOUISIANA...3 TO 6 FT * FLORIDA PANHANDLE AND APALACHEE BAY...2 TO 4 FT THE DEEPEST WATER WILL OCCUR ALONG THE IMMEDIATE COAST IN AREAS OF ONSHORE WINDS. SURGE-RELATED FLOODING DEPENDS ON THE RELATIVE TIMING OF THE SURGE AND THE TIDAL CYCLE...AND CAN VARY GREATLY OVER SHORT DISTANCES. FOR INFORMATION SPECIFIC TO YOUR AREA...PLEASE SEE PRODUCTS ISSUED BY YOUR LOCAL WEATHER SERVICE OFFICE. NEAR THE COAST...THE SURGE WILL BE ACCOMPANIED BY LARGE AND DANGEROUS WAVES. STORM SURGE VALUES OF ABOUT 8 FEET HAVE RECENTLY BEEN REPORTED AT WAVELAND MISSISSIPPI. WIND...TROPICAL STORM CONDITIONS WILL CONTINUE ACROSS THE WARNING AREA TODAY. WINDS AFFECTING THE UPPER FLOORS OF HIGH-RISE BUILDINGS WILL BE SIGNIFICANTLY STRONGER THAN THOSE NEAR GROUND LEVEL. AT ABOUT THE 30TH STORY...WINDS WOULD LIKELY BE ONE SAFFIR-SIMPSON CATEGORY STRONGER THAN AT THE SURFACE. RAINFALL...ISAAC IS EXPECTED TO PRODUCE TOTAL RAINFALL AMOUNTS OF 7 TO 14 INCHES...WITH POSSIBLE ISOLATED MAXIMUM AMOUNTS OF 20 INCHES...OVER MUCH OF LOUISIANA...SOUTHERN MISSISSIPPI...AND SOUTHWEST ALABAMA THROUGH FRIDAY MORNING. THESE RAINS COULD RESULT IN SIGNIFICANT LOWLAND FLOODING. RAINS ARE EXPECTED TO INCREASE NORTHWARD INTO ARKANSAS ON THURSDAY...WITH AMOUNTS OF 3 TO 6 INCHES EXPECTED OVER SOUTHERN ARKANSAS BY FRIDAY MORNING. TORNADOES...ISOLATED TORNADOES ARE POSSIBLE ALONG THE CENTRAL GULF COAST REGION AND PARTS OF THE LOWER MISSISSIPPI RIVER VALLEY THROUGH THURSDAY. SURF...DANGEROUS SURF AND RIP CURRENT CONDITIONS WILL CONTINUE TO AFFECT THE WEST COAST OF FLORIDA AND THE NORTHERN GULF COAST FOR THE NEXT DAY OR SO. NEXT ADVISORY ------------- NEXT COMPLETE ADVISORY...400 PM CDT. $$ FORECASTER STEWART