000
WTPZ45 KNHC 151454
TCDEP5
TROPICAL STORM ISELLE DISCUSSION NUMBER   9
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   EP102008
800 AM PDT FRI AUG 15 2008
 
ALTHOUGH PERIODIC BURSTS OF CONVECTION HAVE CONTINUED TO DEVELOP
NEAR AND SOUTHWEST OF THE LOW-LEVEL CENTER...THE GENERAL TREND HAS
BEEN FOR CLOUD TOPS TO WARM AND THE CONVECTIVE ORGANIZATION TO
DECREASE OWING TO MODERATE EASTERLY UPPER-LEVEL SHEAR. THE INITIAL
INTENSITY HAS BEEN MAINTAINED AT 35 KT BASED ON A CONSENSUS DVORAK
CURRENT INTENSITY OF T2.5/35 KT.
 
AN AQUA MICROWAVE OVERPASS AT 15/0859Z INDICATED THAT THE LOW-LEVEL
CENTER WAS A LITTLE EAST OF THE PREVIOUS ADVISORY POSITION. OTHER
THAN A SLIGHT EASTWARD RELOCATION OF THE CENTER...THE GENERAL TRACK
FORECAST REMAINS UNCHANGED FORM THE PREVIOUS ADVISORY. ISELLE IS
EXPECTED TO GRADUALLY WEAKEN INTO A NON-CONVECTIVE LOW PRESSURE
SYSTEM DURING THE NEXT 24 HOURS OR SO...WITH THE EXPOSED LOW-LEVEL
CIRCULATION BEING STEERED MORE WESTWARD BY AN EAST-WEST ORIENTED
RIDGE SITUATED TO THE NORTH OF THE CYCLONE.
 
ALTHOUGH WATER VAPOR IMAGERY AND SATELLITE-DERIVED WINDS INDICATE
THE UPPER-LEVEL FLOW IS QUITE DIFLUENT...THE 20-30 KT WINDS
IMPINGING ON THE CYCLONE IS CREATING MODERATE VERTICAL SHEAR
CONDITIONS. ALL AVAILABLE GUIDANCE SUGGEST THAT THESE HOSTILE
CONDITIONS WILL PERSIST THROUGHOUT THE FORECAST PERIOD...WHICH LEAD
TO THE FORECAST WEAKENING TREND.
  
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      15/1500Z 17.7N 111.4W    35 KT
 12HR VT     16/0000Z 18.0N 112.4W    35 KT
 24HR VT     16/1200Z 18.3N 113.5W    30 KT
 36HR VT     17/0000Z 18.4N 114.4W    30 KT
 48HR VT     17/1200Z 18.4N 115.3W    25 KT...REMNANT LOW
 72HR VT     18/1200Z 18.5N 117.0W    20 KT...REMNANT LOW
 96HR VT     19/1200Z 18.5N 118.5W    20 KT...REMNANT LOW
120HR VT     20/1200Z 18.5N 120.0W    20 KT...REMNANT LOW
 
$$
FORECASTER STEWART/BEVEN