Hurricane IKE

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HURRICANE IKE DISCUSSION NUMBER  13
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   AL092008
500 AM EDT THU SEP 04 2008

SATELLITE IMAGES INDICATE THAT IKE HAS INTENSIFIED FURTHER...WITH
THE EYE EMBEDDED IN EVEN COLDER CLOUD TOPS THAN BEFORE.  THE LATEST
DVORAK DATA T-NUMBERS ARE UP TO 6.5 WHICH SUPPORTS AN INTENSITY OF
125 KT...AND THIS IS USED FOR THE CURRENT ADVISORY.  IN SUCH
INTENSE HURRICANES...FLUCTUATIONS IN STRENGTH DUE TO INNER-CORE
EVOLUTIONS SUCH AS EYEWALL REPLACEMENTS ARE NEARLY IMPOSSIBLE TO
PREDICT.  HOWEVER...THE SHIPS MODEL SHOWS OVER 30 KT OF VERTICAL
SHEAR ON IKE WITHIN THE NEXT 24-36 HOURS DUE TO A STRENGTHENING
UPPER-LEVEL HIGH TO THE NORTHWEST OF THE HURRICANE.  THIS
LARGE-SCALE ENVIRONMENTAL INFLUENCE SHOULD INDUCE SOME WEAKENING...
AND THAT IS WHAT IS INDICATED IN THE OFFICIAL WIND SPEED FORECAST. 
LATER ON IN THE FORECAST PERIOD...SOME RE-STRENGTHENING IS PROBABLE
AS THE SHEAR WEAKENS AND THE THERMODYNAMIC ENVIRONMENT IS EXPECTED
TO BE FAVORABLE.  THE OFFICIAL FORECAST MIGHT BE CONSERVATIVE BUT
IT REFLECTS OUR LACK OF SKILL IN FORECASTING TROPICAL CYCLONE
INTENSITY IN 3-5 DAYS.

IKE CONTINUES TO MOVE WEST-NORTHWESTWARD OR AROUND 290/15.  THERE
HAS BEEN LITTLE CHANGE TO THE TRACK FORECAST OR FORECAST REASONING. 
A DEEP-LAYER HIGH IS DEPICTED BY THE GLOBAL MODELS TO BUILD TO THE
NORTHWEST OF THE HURRICANE WITHIN THE NEXT COUPLE OF DAYS.  THIS
WOULD LIKELY CAUSE THE HEADING OF IKE TO BEND WESTWARD TO
WEST-SOUTHWESTWARD.  LATE IN THE FORECAST PERIOD IT IS EXPECTED
THAT IKE WILL HAVE PASSED THE CENTER OF THE HIGH...AND TURN BACK
TOWARD THE WEST AND WEST-NORTHWEST.  THE BIG QUESTIONS IS HOW THE
HURRICANE RESPONDS TO THE WEAKNESS IN THE MID-TROPOSPHERIC RIDGE
OVER THE SOUTHEASTERN U.S. AROUND DAY 5.  LOOKING AT THE VARIOUS
TRACK MODELS IN THIS TIME FRAME...WE SEE THAT THE ECMWF IS THE
WESTERNMOST AND THE GFS IS THE NORTHEASTERNMOST.  THE OFFICIAL
TRACK FORECAST LIES BETWEEN THESE EXTREMES AND LEANS TOWARD THE
ECMWF.  THIS IS A LITTLE TO THE LEFT OF THE DYNAMICAL MODEL
CONSENSUS AND QUITE SIMILAR TO THE PREVIOUS NHC FORECAST.  

BECAUSE OF THE UNCERTAINTIES IN 4- AND 5-DAY TRACK FORECASTS...IT IS
STILL TOO EARLY TO SAY WHAT LAND AREAS ARE LIKELY TO BE IMPACTED BY
THIS HURRICANE.
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      04/0900Z 22.7N  55.8W   125 KT
 12HR VT     04/1800Z 23.5N  57.7W   125 KT
 24HR VT     05/0600Z 24.0N  60.2W   115 KT
 36HR VT     05/1800Z 24.0N  62.6W   110 KT
 48HR VT     06/0600Z 23.4N  64.9W   110 KT
 72HR VT     07/0600Z 22.5N  69.5W   115 KT
 96HR VT     08/0600Z 23.0N  73.5W   115 KT
120HR VT     09/0600Z 25.0N  76.5W   115 KT
 
$$
FORECASTER PASCH
 
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