|
Show Selection: |
| #215476 (Received by flhurricane at: 11:12 PM 10.Sep.2008) TCDAT4 HURRICANE IKE DISCUSSION NUMBER 40 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL092008 1100 PM EDT WED SEP 10 2008 OVERALL...IKE IS A LARGE CYCLONE...AS DATA FROM BOTH AIR FORCE AND NOAA HURRICANE HUNTER AIRCRAFT INDICATE THAT THE EXTENT OF WINDS OF HURRICANE AND TROPICAL STORM FORCE HAS INCREASED...ESPECIALLY NORTH OF THE CIRCULATION CENTER. PARADOXICALLY...IKE HAS A VERY SMALL INNER CORE...AND THE EYE HAS A DIAMETER OF ONLY ABOUT 8 TO 10 N MI. THE CENTRAL PRESSURE HAS BEEN STEADILY FALLING...NOW DOWN TO ABOUT 944 MB...BUT THE WINDS HAVE NOT YET RESPONDED. THE INITIAL INTENSITY REMAINS 85 KT BASED ON RECENT SFMR WIND SPEED RETRIEVALS. THE SHORT-TERM INTENSITY FORECAST IS CONTINGENT UPON HOW LONG THE EXTREMELY SMALL INNER CORE SURVIVES. SINCE IT COULD DISINTEGRATE AT ANY TIME...AND SINCE IKE WILL BE PASSING NEAR OR OVER A COLD EDDY IN THE CENTRAL GULF DURING THE NEXT 24 HOURS...THE HURRICANE COULD WEAKEN. IF...HOWEVER...THE TENACIOUS INNER CORE REMAINS INTACT...AND GIVEN THE RECENT PRESSURE FALLS...IKE COULD STRENGTHEN SOME AS REFLECTED IN THE OFFICIAL FORECAST. BEYOND 24 HOURS...THE UNDERLYING OCEAN HEAT CONTENT WILL INCREASE ALONG THE FORECAST TRACK...AND IKE WILL REMAIN WITHIN A WEAK WIND SHEAR ENVIRONMENT...SO MORE ROBUST STRENGTHENING IS FORECAST AT 36-48 HOURS. THE NEW OFFICIAL INTENSITY FORECAST IS A LITTLE LOWER THAN THE PREVIOUS ONE THROUGH 24 HOURS BUT IS SIMILAR THEREAFTER...AND IS ROUGHLY A BLEND OF THE HWRF AND GFDL...BUT HIGHER THAN SHIPS AND LGEM. THE APPARENT WEAKENING BETWEEN 48 AND 72 HOURS IMPLIED BY THE OFFICIAL FORECAST SHOWN BELOW ONLY RESULTS FROM IKE GOING INLAND...BUT NO WEAKENING TREND IS ACTUALLY ANTICIPATED LEADING UP TO FINAL LANDFALL. THE CENTER OF IKE HAS CONTINUED TO MOVE NORTHWESTWARD OR 315/6...A LITTLE TO THE RIGHT OF THE PREVIOUS FORECAST TRACK...BUT VERY RECENT SATELLITE IMAGERY AND THE LAST FIX FROM THE NOAA HURRICANE HUNTER AIRCRAFT SUGGESTS THE TURN TOWARD THE WEST-NORTHWEST COULD BE STARTING. ALL MODEL GUIDANCE FORECASTS A WEST-NORTHWESTWARD MOTION DURING THE NEXT 48 HOURS TO THE SOUTH OF A STRONG RIDGE OVER THE SOUTHEASTERN UNITED STATES THAT IS FORECAST TO BUILD WESTWARD. IN A COUPLE OF DAYS...ALL OF THE MODELS FORECAST A WEAKNESS IN THE RIDGE TO DEVELOP OVER TEXAS AND EVENTUALLY INDUCE A TURN TO THE NORTHWEST AND NORTH...BUT THEY DO NOT AGREE ON WHEN THAT TURN WILL OCCUR. THE HWRF IS ON THE LEFT SIDE OF THE GUIDANCE ENVELOPE AND FORECASTS A STRONGER AND LONGER-LASTING RIDGE THAT TAKES IKE INTO DEEP SOUTH TEXAS BEFORE TURNING NORTH. CONVERSELY...THE GFDL IS THE RIGHTMOST MODEL WITH A WEAKER RIDGE THAT ALLOWS IKE TO TURN INTO THE GALVESTON AREA. THE OTHER MODELS ARE IN BETWEEN...AS IS THE OFFICIAL FORECAST....WHICH IS NOT APPRECIABLY CHANGED FROM THE PREVIOUS ADVISORY SINCE THE MODEL CONSENSUS HAS BARELY BUDGED. SINCE THE TIMING OF THE TURN BEFORE LANDFALL IS SO UNCERTAIN AND SO KEY IN WHERE THE CORE OF IKE COMES ASHORE...AND SINCE IKE WILL BE ROUNDING THE RIDGE AND NOT GOING IN A STRAIGHT LINE BETWEEN 48 AND 72 HOURS...ONE SHOULD NOT FOCUS ON THE EXACT TRACK. EVERYONE IN THE HURRICANE WATCH AREA HAS ABOUT THE SAME RISK OF HURRICANE CONDITIONS. FORECAST POSITIONS AND MAX WINDS INITIAL 11/0300Z 24.9N 86.7W 85 KT 12HR VT 11/1200Z 25.4N 88.0W 90 KT 24HR VT 12/0000Z 26.0N 90.0W 95 KT 36HR VT 12/1200Z 26.7N 92.4W 100 KT 48HR VT 13/0000Z 27.7N 94.6W 110 KT 72HR VT 14/0000Z 31.5N 96.5W 55 KT...INLAND 96HR VT 15/0000Z 36.0N 93.0W 30 KT...INLAND 120HR VT 16/0000Z...ABSORBED $$ FORECASTER KNABB |
