000 WTNT34 KNHC 301740 TCPAT4 BULLETIN TROPICAL STORM ISAAC INTERMEDIATE ADVISORY NUMBER 38A NWS NATIONAL HURRICANE CENTER MIAMI FL AL092012 100 PM CDT THU AUG 30 2012 ...SLOW-MOVING ISAAC DRENCHING SOUTHEASTERN LOUISIANA AND MISSISSIPPI WITH HEAVY RAINFALL... ...SIGNIFICANT STORM SURGE CONTINUES... SUMMARY OF 100 PM CDT...1800 UTC...INFORMATION ---------------------------------------------- LOCATION...32.2N 92.3W ABOUT 25 MI...45 KM SW OF MONROE LOUISIANA MAXIMUM SUSTAINED WINDS...40 MPH...65 KM/H PRESENT MOVEMENT...NNW OR 330 DEGREES AT 9 MPH...15 KM/H MINIMUM CENTRAL PRESSURE...992 MB...29.29 INCHES WATCHES AND WARNINGS -------------------- CHANGES WITH THIS ADVISORY... NONE. SUMMARY OF WATCHES AND WARNINGS IN EFFECT... A TROPICAL STORM WARNING IS IN EFFECT FOR... * MORGAN CITY LOUISIANA TO THE MISSISSIPPI-ALABAMA BORDER... INCLUDING LAKE PONTCHARTRAIN AND LAKE MAUREPAS 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 32.2 NORTH...LONGITUDE 92.3 WEST. ISAAC IS MOVING TOWARD THE NORTH-NORTHWEST NEAR 9 MPH...15 KM/H. A TURN TOWARD THE NORTH IS EXPECTED BY LATE TONIGHT OR EARLY FRIDAY. ON THE FORECAST TRACK...THE CENTER OF ISAAC WILL CONTINUE TO MOVE OVER LOUISIANA TODAY...OVER ARKANSAS ON FRIDAY...AND OVER SOUTHERN MISSOURI FRIDAY NIGHT. MAXIMUM SUSTAINED WINDS ARE NEAR 40 MPH...65 KM/H... WITH HIGHER GUSTS. WEAKENING IS FORECAST DURING THE NEXT 48 HOURS AS THE STORM CONTINUES TO MOVE OVER LAND...AND ISAAC IS EXPECTED TO BECOME A TROPICAL DEPRESSION THIS AFTERNOON OR TONIGHT. TROPICAL-STORM-FORCE WINDS EXTEND OUTWARD UP TO 195 MILES...315 KM...MAINLY TO THE SOUTHEAST OF THE CENTER OVER WATER AND ALSO ALONG THE COASTS OF MISSISSIPPI AND SOUTHEASTERN LOUISIANA. THE ESTIMATED MINIMUM CENTRAL PRESSURE BASED ON NEARBY SURFACE OBSERVATIONS 992 MB...29.29 INCHES. HAZARDS AFFECTING LAND ---------------------- EVEN THOUGH ISAAC IS NO LONGER A HURRICANE...LIFE-THREATENING HAZARDS FROM STORM SURGE...INLAND FLOODING...AND TORNADOES 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...4 TO 8 FT * ALABAMA...2 TO 4 FT * SOUTH-CENTRAL LOUISIANA...1 TO 3 FT * FLORIDA PANHANDLE...1 TO 2 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. BASED ON OBSERVATIONS FROM NATIONAL OCEAN SERVICE TIDE GAGES...AT NEW CANAL STATION LOUISIANA...A STORM SURGE OF NEAR 6 FEET IS PERSISTING ALONG THE SOUTHERN SHORE OF LAKE PONTCHARTRAIN...AND A STORM SURGE VALUE OF NEAR 5 FEET CONTINUES AT WAVELAND MISSISSIPPI. WIND...TROPICAL STORM CONDITIONS WILL CONTINUE ACROSS THE WARNING AREA THROUGH THIS AFTERNOON. RAINFALL...ISAAC IS EXPECTED TO PRODUCE TOTAL RAINFALL ACCUMULATIONS OF 7 TO 14 INCHES...WITH ISOLATED MAXIMUM AMOUNTS OF 25 INCHES POSSIBLE...OVER NORTHERN AND EASTERN LOUISIANA....MUCH OF MISSISSIPPI...SOUTHWESTERN ALABAMA...ARKANSAS AND INTO SOUTHERN MISSOURI THROUGH FRIDAY. THESE RAINS COULD RESULT IN SIGNIFICANT LOWLAND FLOODING. THE HEAVY RAIN POTENTIAL WILL BE SPREADING EASTWARD THIS WEEKEND INTO PORTIONS OF THE MID-WEST AND OHIO VALLEY REGIONS. TORNADOES...TORNADOES ARE POSSIBLE ALONG THE CENTRAL GULF COAST REGION AND PARTS OF THE LOWER MISSISSIPPI RIVER VALLEY THROUGH TODAY. 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