Official Discussion issued by the National Hurricane Center

IKE (AL092008) DATA RELEASED: 9/11/2008 3:00:00 AM UTC

Copy of official data

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