000 WTNT42 KNHC 311457 TCDAT2 HURRICANE GUSTAV DISCUSSION NUMBER 28 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL072008 1100 AM EDT SUN AUG 31 2008 GUSTAV CONTINUES TO LOOK SOMEWHAT RAGGED IN SATELLITE APPEARANCE THIS MORNING. THE DEEP CONVECTION IS VERY ASYMMETRIC...WITH THE COLD TOPS DUE MAINLY TO ONE HOT TOWER IN THE WESTERN EYEWALL. WHILE AN EYE-LIKE FEATURE IS APPARENT...IT IS DISPLACED TO THE NORTHEAST OF THE AIRCRAFT-REPORTED CENTER. THE LATEST REPORT FROM A NOAA HURRICANE HUNTER INDICATES THE CENTRAL PRESSURE HAS RISEN TO 962 MB...ALONG WITH AN ELLIPTICAL 30 BY 20 N MI WIDE EYE OPEN TO THE SOUTHEAST. THE INITIAL INTENSITY IS REDUCED TO 105 KT...AND THIS MIGHT BE A LITTLE GENEROUS BASED ON THE AIRCRAFT WINDS. THE INITIAL MOTION IS 320/15. THERE IS NO CHANGE IN THE FORECAST PHILOSOPHY FOR THE EARLY PORTION OF THE FORECAST TRACK...WITH A MID-LEVEL RIDGE OVER THE EASTERN UNITED STATES EXPECTED TO STEER GUSTAV NORTHWESTWARD INTO THE NORTHERN GULF COAST. THE NEW GUIDANCE RUNS SHOW A SLIGHT LEFT TURN AFTER 12 HR WITH A LEFTWARD SHIFT IN THE LANDFALL POINT ON THE LOUISIANA COAST. THE NEW FORECAST TRACK WILL NOT FOLLOW THIS SHIFT YET...AND THUS LIES NEAR THE EASTERN EDGE OF THE GUIDANCE ENVELOPE AND THE PREVIOUS FORECAST TRACK THROUGH 48 HR. AFTER 48-72 HR...THERE IS MAJOR DISAGREEMENT BETWEEN THE DYNAMICAL MODELS ON WHETHER GUSTAV WILL RECURVE INTO THE WESTERLIES...STALL OVER LOUISIANA OR TEXAS...OR TURN SOUTHWESTWARD. SINCE THIS KIND OF SPREAD FREQUENTLY PRECEDES SLOW MOTION...THE FORECAST TRACK WILL CALL FOR A SLOW WESTWARD MOTION AFTER 72 HR. AT THE RISK OF SOUNDING LIKE A BROKEN RECORD...THE INTENSITY FORECAST REMAINS PROBLEMATIC. ANALYSES FROM CIMSS AT THE UNIVERSITY OF WISCONSIN SHOWS THAT GUSTAV REMAINS IN 15 TO 20 KT OF SOUTHERLY VERTICAL SHEAR....AND THE LARGE-SCALE MODELS FORECAST AT LEAST SOME SOUTHERLY TO SOUTHWESTERLY SHEAR TO PERSIST UNTIL LANDFALL. THAT...COMBINED WITH THE CURRENT RAGGED STORM STRUCTURE AND THE MID-LEVEL DRY AIR TRYING TO WRAP AROUND THE STORM IN WATER VAPOR IMAGERY...SUGGESTS ANY INTENSIFICATION SHOULD BE SLOW. ADDITIONALLY..GUSTAV IS OVER A WARM EDDY IN THE LOOP CURRENT NOW...AND SHOULD PASS OVER WATERS WITH LOWER OCEANIC HEAT CONTENT BETWEEN NOW AND LANDFALL. THE GUIDANCE RESPONDS TO THESE FACTORS BY FORECASTING MODEST STRENGTHENING DURING THE NEXT 12 TO 24 HR...WITH THE GFDL FORECASTING A PEAK INTENSITY OF 120 KT AND THE OTHER MODELS ABOUT 110 KT. BASED ON THIS...THE INTENSITY FORECAST WILL CALL FOR GUSTAV TO RE-INTENSIFY TO 115 KT IN 12 TO 24 HR...AND MAKE LANDFALL ON THE NORTHERN GULF COAST AS A MAJOR HURRICANE. GUSTAV SHOULD STEADILY WEAKEN AFTER LANDFALL. FORECAST POSITIONS AND MAX WINDS INITIAL 31/1500Z 25.3N 86.0W 105 KT 12HR VT 01/0000Z 27.0N 87.7W 115 KT 24HR VT 01/1200Z 28.6N 89.7W 115 KT 36HR VT 02/0000Z 30.0N 91.5W 85 KT...INLAND 48HR VT 02/1200Z 31.1N 93.0W 50 KT...INLAND 72HR VT 03/1200Z 32.0N 94.5W 30 KT...INLAND 96HR VT 04/1200Z 32.0N 95.0W 25 KT...INLAND 120HR VT 05/1200Z 32.0N 95.9W 20 KT...INLAND REMNANT LOW $$ FORECASTER BEVEN