775 
 WTNT44 KNHC 051444
 TCDAT4
 HURRICANE IKE DISCUSSION NUMBER  18
 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   AL092008
 1100 AM EDT FRI SEP 05 2008
 
 NORTHERLY SHEAR CONTINUES TO A TAKE A TOLL ON IKE. SATELLITE IMAGES
 SHOW THAT THE EYE HAS BECOME LESS CLEAR AND THAT MOST OF THE
 CONVECTION IS IN THE SOUTHERN SEMICIRCLE. IN ADDITION...A RECENT
 SSMIS MICROWAVE IMAGE SHOWS THAT THE EYEWALL IS OPEN ON THE NORTH
 SIDE. USING A BLEND OF THE OBJECTIVE AND SUBJECTIVE DVORAK
 CLASSIFICATIONS...THE INITIAL INTENSITY IS LOWERED TO 105 KT...AND
 THIS COULD BE GENEROUS. AN AIR FORCE RESERVE RECONNAISSANCE PLANE
 IS SCHEDULED TO INVESTIGATE THE HURRICANE THIS AFTERNOON TO OBTAIN
 A BETTER ESTIMATE OF THE CURRENT INTENSITY AND WIND RADII. ALMOST
 ALL OF THE GLOBAL MODELS SHOW DECREASING SHEAR OVER IKE IN ABOUT A
 DAY DUE TO A WEAKENING OF STRONG NORTHEASTERLY UPPER WINDS. EXCEPT
 FOR A SMALL PATCH OF SSTS NEAR AND NORTH OF THE SOUTHEASTERN
 BAHAMAS...WATERS ARE VERY WARM ALONG THE FORECAST PATH. THE
 OFFICIAL FORECAST SHOWS A SLOW WEAKENING OF THE HURRICANE DUE TO
 THE SHEAR FOR THE FIRST 24 HOURS...THEN SHOWS INTENSIFICATION AS
 UPPER-WINDS SLACKEN...IN GENERAL AGREEMENT WITH THE LGEM MODEL. IN
 A COUPLE DAYS...VERTICAL WIND SHEAR WILL LIKELY BECOME LIGHT...AND
 CONDITIONS LOOK RATHER FAVORABLE FOR INTENSIFICATION. THE OFFICIAL
 FORECAST COULD BE CONSERVATIVE IN THE LONGER-RANGE AS THE HWRF AND
 GFDL SHOW A MORE INTENSE HURRICANE. REGARDLESS OF EXACTLY HOW
 STRONG IT IS...ALL SIGNS ARE THAT IKE WILL BE A DANGEROUS HURRICANE
 FOR DAYS TO COME.
 
 IKE HAS BEEN MOVING SOUTH OF WEST DURING THE PAST FEW HOURS...ABOUT
 260/14. THIS GENERAL TRACK WITH SOME DECREASE IN FORWARD SPEED IS
 FORECAST OVER THE NEXT 36 HOURS DUE TO A STRONG RIDGE WEDGING INTO
 BETWEEN IKE AND HANNA. THE RIDGE SHOULD WEAKEN SOMEWHAT IN A COUPLE
 OF DAYS...STEERING THE HURRICANE MORE TO THE WEST AND EVENTUALLY
 WEST-NORTHWEST. HOWEVER...MODELS ARE NOT IN GOOD AGREEMENT ON WHEN
 THIS WEST-NORTHWEST MOTION COULD MATERIALIZE. GENERALLY THE MODELS
 THAT DRIVE THE SYSTEM FARTHER SOUTH...SUCH AS THE ECMWF/HWRF/GFDL
 MODELS...SUGGEST THE RIDGE WILL REMAIN INTACT ENOUGH TO EVENTUALLY
 SEND IKE TOWARD CUBA OR THE SOUTHEASTERN GULF OF MEXICO. THE
 UKMET/GFDN/NOGAPS...ON THE OTHER HAND...SUGGEST THE HURRICANE WILL
 MOVE MORE THE WEST AND HAS A BETTER CHANCE OF BEING AFFECTED BY A
 WEAKNESS IN THE RIDGE AROUND 80W. SINCE THE HURRICANE IS MOVING
 WELL SOUTH OF THE LATTER CLUSTER OF MODELS ALREADY...THE OFFICIAL
 FORECAST LEANS MORE TOWARD THE SOUTHERN GUIDANCE AND SHIFTED
 SOUTHWEST OF THE PREVIOUS FORECAST. 
 
 IT CANNOT BE REPEATED ENOUGH THAT FOUR- AND FIVE-DAY TRACK FORECASTS
 CAN HAVE SIGNIFICANT ERRORS...AND COMBINED WITH THE FACT THAT THE
 MODEL SPREAD IS STILL NOTABLE BEYOND 72 HOURS...ONE SHOULD NOT
 FOCUS ON THE EXACT TRACK.
  
  
 FORECAST POSITIONS AND MAX WINDS
  
 INITIAL      05/1500Z 23.2N  62.7W   105 KT
  12HR VT     06/0000Z 22.9N  64.7W    95 KT
  24HR VT     06/1200Z 22.5N  67.4W    90 KT
  36HR VT     07/0000Z 22.2N  69.9W    95 KT
  48HR VT     07/1200Z 22.2N  72.5W   105 KT
  72HR VT     08/1200Z 23.0N  77.0W   115 KT
  96HR VT     09/1200Z 24.0N  80.0W   115 KT
 120HR VT     10/1200Z 25.5N  82.0W   100 KT
  
 $$
 FORECASTER BLAKE