000 WTNT34 KNHC 271759 TCPAT4 BULLETIN TROPICAL STORM ISAAC INTERMEDIATE ADVISORY NUMBER 26A NWS NATIONAL HURRICANE CENTER MIAMI FL AL092012 100 PM CDT MON AUG 27 2012 ...HEAVY RAINS AND FLOODING AFFECTING THE FLORIDA EAST COAST... SIGNIFICANT STORM SURGE THREAT EXPECTED FOR THE NORTHERN GULF COAST... SUMMARY OF 100 PM CDT...1800 UTC...INFORMATION ---------------------------------------------- LOCATION...26.1N 85.9W ABOUT 255 MI...410 KM SSW OF APALACHICOLA FLORIDA ABOUT 280 MI...450 KM SE OF THE MOUTH OF THE MISSISSIPPI RIVER MAXIMUM SUSTAINED WINDS...65 MPH...100 KM/H PRESENT MOVEMENT...NW OR 305 DEGREES AT 14 MPH...22 KM/H MINIMUM CENTRAL PRESSURE...984 MB...29.06 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 DESTIN FLORIDA...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... * EAST OF DESTIN FLORIDA TO THE AUCILLA RIVER * INTRACOASTAL CITY TO MORGAN CITY LOUISIANA A TROPICAL STORM WATCH IS IN EFFECT FOR... * EAST OF SABINE PASS TO WEST OF INTRACOASTAL CITY 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 WITHIN 36 HOURS. A TROPICAL STORM WATCH MEANS THAT TROPICAL STORM CONDITIONS ARE POSSIBLE WITHIN THE WATCH AREA...GENERALLY WITHIN 48 HOURS. 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 100 PM CDT...1800 UTC...THE CENTER OF TROPICAL STORM ISAAC WAS LOCATED NEAR LATITUDE 26.1 NORTH...LONGITUDE 85.9 WEST. ISAAC IS MOVING TOWARD THE NORTHWEST NEAR 14 MPH...22 KM/H...AND THIS GENERAL MOTION IS EXPECTED TO CONTINUE TODAY WITH A GRADUAL DECREASE IN FORWARD SPEED. ON THE FORECAST TRACK...THE CENTER OF ISAAC WILL MOVE OVER THE EASTERN GULF OF MEXICO TODAY AND APPROACH THE NORTHERN GULF COAST IN THE HURRICANE WARNING AREA ON TUESDAY. MAXIMUM SUSTAINED WINDS ARE NEAR 65 MPH...100 KM/H...WITH HIGHER GUSTS. SOME STRENGTHENING IS FORECAST DURING THE NEXT 48 HOURS... AND ISAAC IS EXPECTED TO BECOME A HURRICANE BEFORE REACHING THE NORTHERN GULF COAST. TROPICAL-STORM-FORCE WINDS EXTEND OUTWARD UP TO 205 MILES...335 KM FROM THE CENTER. THE ESTIMATED MINIMUM CENTRAL PRESSURE BASED ON REPORTS FROM A NEARBY NOAA BUOY IS 984 MB...29.06 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...MISSISSIPPI...AND ALABAMA...6 TO 12 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 FLOW. 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 SPREAD NORTHWARD INTO THE FLORIDA BIG BEND AREA AND THE FLORIDA PANHANDLE IN THE TROPICAL STORM WARNING AREA TONIGHT. TROPICAL STORM CONDITIONS ARE EXPECTED TO REACH THE NORTHERN GULF COAST IN THE HURRICANE WARNING AREA LATER TONIGHT...WITH HURRICANE CONDITIONS EXPECTED ON TUESDAY. RAINFALL...ISAAC IS EXPECTED TO PRODUCE ADDITIONAL RAIN ACCUMULATIONS OF 1 TO 3 INCHES OVER MUCH OF THE FLORIDA PENINSULA. HEAVY RAINS ARE OCCURRING OVER THE EAST COAST OF FLORIDA...WHERE ISOLATED MAXIMUM STORM TOTAL AMOUNTS OF 15 TO 20 INCHES ARE POSSIBLE. TOTAL RAINFALL AMOUNTS OF 6 TO 12 INCHES...WITH MAXIMUM AMOUNTS OF 18 INCHES...ARE POSSIBLE IN SOUTHEASTERN LOUISIANA... SOUTHERN MISSISSIPPI...SOUTHERN ALABAMA AND THE WESTERN FLORIDA PANHANDLE. TORNADOES...ISOLATED TORNADOES ARE POSSIBLE IN CENTRAL AND NORTHERN FLORIDA TODAY...AND ALONG THE NORTHERN GULF COAST TONIGHT AND TUESDAY. SURF...DANGEROUS SURF AND RIP CURRENT CONDITIONS WILL CONTINUE TO AFFECT THE FLORIDA COASTLINE AND THE FLORIDA KEYS DURING THE NEXT DAY OR SO...AND BEGIN TO AFFECT PORTIONS OF THE NORTHERN GULF COAST LATER TODAY. NEXT ADVISORY ------------- NEXT COMPLETE ADVISORY...400 PM CDT. $$ FORECASTER STEWART