000 WTNT34 KNHC 281149 TCPAT4 BULLETIN TROPICAL STORM ISAAC INTERMEDIATE ADVISORY NUMBER 29A NWS NATIONAL HURRICANE CENTER MIAMI FL AL092012 700 AM CDT TUE AUG 28 2012 ...RECONNAISSANCE AIRCRAFT FIND ISAAC NEARLY A HURRICANE... SIGNIFICANT STORM SURGE AND FRESHWATER FLOOD THREAT TO THE NORTHERN GULF COAST... SUMMARY OF 700 AM CDT...1200 UTC...INFORMATION ---------------------------------------------- LOCATION...27.8N 88.2W ABOUT 105 MI...170 KM SSE OF THE MOUTH OF THE MISSISSIPPI RIVER ABOUT 185 MI...295 KM SSE OF BILOXI MISSISSIPPI MAXIMUM SUSTAINED WINDS...70 MPH...110 KM/H PRESENT MOVEMENT...NW OR 305 DEGREES AT 7 MPH...11 KM/H MINIMUM CENTRAL PRESSURE...976 MB...28.82 INCHES WATCHES AND WARNINGS -------------------- CHANGES WITH THIS ADVISORY... NONE. SUMMARY OF WATCHES AND WARNINGS IN EFFECT... A HURRICANE WARNING IS IN EFFECT FOR... * EAST OF MORGAN CITY LOUISIANA TO THE ALABAMA-FLORIDA BORDER... INCLUDING METROPOLITAN NEW ORLEANS...LAKE PONTCHARTRAIN...AND LAKE MAUREPAS A HURRICANE WATCH IS IN EFFECT FOR... * INTRACOASTAL CITY TO MORGAN CITY LOUISIANA A TROPICAL STORM WARNING IS IN EFFECT FOR... * THE ALABAMA-FLORIDA BORDER TO THE AUCILLA RIVER * MORGAN CITY TO CAMERON LOUISIANA A TROPICAL STORM WATCH IS IN EFFECT FOR... * EAST OF HIGH ISLAND TEXAS TO JUST WEST OF CAMERON LOUISIANA 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 HURRICANE WATCH MEANS THAT HURRICANE CONDITIONS ARE POSSIBLE WITHIN THE WATCH AREA. A TROPICAL STORM WARNING MEANS THAT TROPICAL STORM CONDITIONS ARE EXPECTED SOMEWHERE WITHIN THE WARNING AREA. A TROPICAL STORM WATCH MEANS THAT TROPICAL STORM CONDITIONS ARE POSSIBLE WITHIN THE WATCH AREA. 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 700 AM CDT...1200 UTC...THE CENTER OF TROPICAL STORM ISAAC WAS LOCATED NEAR LATITUDE 27.8 NORTH...LONGITUDE 88.2 WEST. ISAAC IS MOVING TOWARD THE NORTHWEST NEAR 7 MPH...11 KM/H...AND THIS GENERAL MOTION IS EXPECTED TO CONTINUE FOR THE NEXT DAY OR TWO WITH SOME FLUCTUATIONS IN FORWARD SPEED. ON THE FORECAST TRACK...THE CENTER WILL BE NEAR OR OVER THE LOUISANA COAST TONIGHT OR EARLY WEDNESDAY. MAXIMUM SUSTAINED WINDS ARE NEAR 70 MPH...110 KM/H...WITH HIGHER GUSTS. STRENGTHENING IS FORECAST...AND ISAAC IS LIKELY TO BECOME A HURRICANE LATER TODAY. ADDITIONAL STRENGTHENING IS FORECAST UNTIL THE CENTER MOVES INLAND. TROPICAL-STORM-FORCE WINDS EXTEND OUTWARD UP TO 205 MILES...335 KM FROM THE CENTER. THE MINIMUM CENTRAL PRESSURE RECENTLY REPORTED BY AIR FORCE RESERVE AND NOAA HURRICANE HUNTER AIRCRAFT WAS 976 MB...28.82 INCHES. HAZARDS AFFECTING LAND ---------------------- 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... * SOUTHEAST LOUISIANA AND MISSISSIPPI...6 TO 12 FT * ALABAMA...4 TO 8 FT * SOUTH-CENTRAL LOUISIANA...3 TO 6 FT * FLORIDA PANHANDLE...3 TO 6 FT * FLORIDA WEST COAST INCLUDING APALACHEE BAY...1 TO 3 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. WIND...TROPICAL STORM CONDITIONS ARE EXPECTED TO REACH THE NORTHERN GULF COAST IN THE HURRICANE WARNING AREA THIS MORNING...WITH HURRICANE CONDITIONS EXPECTED BY THIS AFTERNOON. TROPICAL STORM CONDITIONS ARE EXPECTED TO SPREAD NORTHWARD INTO THE FLORIDA BIG BEND AREA AND THE FLORIDA PANHANDLE IN THE TROPICAL STORM WARNING AREA THIS MORNING. TROPICAL STORM CONDITIONS ARE EXPECTED WITHIN THE TROPICAL STORM WARNING AREA IN LOUISIANA BY TONIGHT. TROPICAL STORM CONDITIONS ARE POSSIBLE ON THE COAST OF SOUTHWESTERN LOUISIANA AND THE UPPER TEXAS COAST BY TONIGHT OR EARLY WEDNESDAY. RAINFALL...ISAAC IS EXPECTED TO PRODUCE TOTAL RAINFALL AMOUNTS OF 7 TO 14 INCHES...WITH POSSIBLE ISOLATED MAXIMUM AMOUNTS OF 20 INCHES...IN SOUTHEASTERN LOUISIANA...SOUTHERN MISSISSIPPI... SOUTHERN ALABAMA...AND THE EXTREME WESTERN FLORIDA PANHANDLE. THESE RAINS COULD RESULT IN SIGNIFICANT LOWLAND FLOODING. TORNADOES...TORNADOES MAY OCCUR ALONG THE NORTHERN GULF COAST TODAY. SURF...DANGEROUS SURF AND RIP CURRENT CONDITIONS WILL CONTINUE TO AFFECT THE FLORIDA COASTLINE AND PORTIONS OF THE NORTHERN GULF COAST FOR THE NEXT DAY OR SO. NEXT ADVISORY ------------- NEXT COMPLETE ADVISORY...1000 AM CDT. $$ FORECASTER STEWART