Official Discussion issued by the National Hurricane Center

IKE (AL092008) DATA RELEASED: 9/4/2008 9:00:00 PM UTC

Copy of official data

HURRICANE IKE DISCUSSION NUMBER  15
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   AL092008
500 PM EDT THU SEP 04 2008
THERE HAS BEEN LITTLE CHANGE TO THE OVERALL APPEARANCE OF IKE DURING
THE PAST FEW HOURS.  IKE IS MAINTAINING A WELL-DEFINED EYE...THOUGH
CLOUD TOPS HAVE WARMED SOME IN THE EYEWALL RECENTLY.  IT IS
INTERESTING THAT WHILE IKE STARTED OUT AS A LARGE SYSTEM...THE
CLOUD CANOPY HAS NOTICEABLY SHRUNK TODAY WITH FEW OUTER BANDS. 
THERE HAS BEEN ONLY A SMALL DECREASE IN OBJECTIVE T-NUMBERS...SO
THE INITIAL INTENSITY IS REDUCED SLIGHTLY TO 115 KT.  STRONG
NORTHEASTERLY SHEAR IS LIKELY DURING THE NEXT DAY OR SO...WHICH
SHOULD CAUSE WEAKENING.  IN FACT...THE SHIPS MODEL RESPONDS TO THE
SHEAR BY WEAKENING THIS SYSTEM TO A CATEGORY ONE HURRICANE...THOUGH
THE GFDL/HWRF ARE CONSIDERABLY HIGHER.  IN A COUPLE DAYS...VERTICAL
WIND SHEAR IS FORECAST TO WEAKEN AND...COMBINED WITH RATHER WARM
WATER WATERS EAST OF THE BAHAMAS...SHOULD RESULT IN
RESTRENGTHENING.  THE HURRICANE'S EXACT TRACK IS IMPORTANT BECAUSE
IT COULD BE IMPACTED BY COOLER WATERS UPWELLED BY HANNA.  THE
OFFICIAL FORECAST IS CLOSE TO THE PREVIOUS ONE BUT IS A LITTLE
LOWER FOR THE FIRST 36 HOURS OUT OF RESPECT FOR THE SHIPS/LGEM
MODELS.  IKE IS EXPECTED TO BE A POWERFUL HURRICANE AS IT
APPROACHES THE BAHAMAS IN A COUPLE OF DAYS.

THE INITIAL MOTION ESTIMATE IS 285/12...SLOWER THAN BEFORE AND A
LITTLE TO THE LEFT.  RIDGING FROM THE CENTRAL ATLANTIC IS FORECAST
TO BUILD TO THE NORTH AND NORTHWEST OF THE TROPICAL CYCLONE...
CAUSING A WEST...AND THEN WEST-SOUTHWEST MOTION OF IKE BY LATE
TOMORROW.  THE STRENGTH OF THE RIDGING BETWEEN IKE AND HANNA WILL
BE CRITICAL TO WHEN AN EVENTUAL TURN TOWARD THE WEST-NORTHWEST WILL
OCCUR IN THE LONG-RANGE.  THERE HAS BEEN A NOTICEABLE WESTWARD
SHIFT IN ALMOST ALL OF THE GLOBAL MODEL GUIDANCE TODAY...WITH THE
GFDL/ECMWF EVEN TAKING THE SYSTEM AS FAR SOUTHWEST AS CUBA.  THE
OTHER MODELS ARE PRETTY CLUSTERED ON A TRACK NEAR OR THROUGH THE
CENTRAL AND NORTHWESTERN BAHAMAS.  THE NHC FORECAST IS SHIFTED
WESTWARD AND IS PRETTY CLOSE TO THE HWRF MODEL.  
ONE SHOULD NOT FOCUS ON THE EXACT 4 AND 5 DAY FORECAST POSITIONS
BECAUSE LARGE UNCERTAINTIES EXIST AT THOSE TIMES.  

FORECAST POSITIONS AND MAX WINDS

INITIAL      04/2100Z 23.6N  58.2W   115 KT
12HR VT     05/0600Z 23.9N  60.0W   105 KT
24HR VT     05/1800Z 23.7N  62.5W    95 KT
36HR VT     06/0600Z 23.2N  65.1W    95 KT
48HR VT     06/1800Z 22.7N  67.7W   100 KT
72HR VT     07/1800Z 22.5N  72.5W   105 KT
96HR VT     08/1800Z 24.0N  76.0W   110 KT
120HR VT     09/1800Z 25.5N  79.0W   110 KT

$$
FORECASTER BLAKE