763 
 WTPZ42 KNHC 160844
 TCDEP2
 TROPICAL STORM ISIS DISCUSSION NUMBER  33
 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
 2 AM PDT THU SEP 16 2004
  
 THE INTENSITY ESTIMATE OF ISIS REMAINS AT 55 KTS BASED ON UW-CIMSS
 AND CSU-CIRA AMSU ALGORITHMS WHICH YIELD A CONSISTENT MINIMUM
 PRESSURE ESTIMATE OF 992 MB AND AN INTENSITY OF 55 KTS. THE CURRENT
 INTENSITY ESTIMATES FROM TAFB...SAB..AND AFWA YIELD A SOMEWHAT
 LOWER INTENSITY OF 45 KTS...HOWEVER THE OFFICIAL INTENSITY IS HELD
 AT 55 KTS BASED ON THE CONSISTENT RESULTS FROM THE OBJECTIVE
 ANALYSES.
 
 THE INITIAL MOTION IS STILL DIFFICULT TO DISCERN...BUT IT APPEARS
 STATIONARY. ISIS REMAINS EMBEDDED IN WEAK STEERING CURRENTS AND IS
 EXPECTED TO CONTINUE DRIFTING WESTWARD OVER THE NEXT FIVE DAYS. THE
 MODEL GUIDANCE FOR THIS ADVISORY CALLS FOR A SLOW WESTWARD TO
 WEST-SOUTHWESTWARD DRIFT...THEREFORE THE OFFICIAL FORECAST TRACK
 FOLLOWS THIS SCENARIO.
 
 SINCE ISIS HAS MOVED GENERALLY NORTHWARD...IT HAS TRACKED OVER
 SLIGHTLY COOLER SSTS OF 25 DEGREES CELSIUS AND THIS HAS LIKELY KEPT
 CONVECTION TO A MINIMUM. HOWEVER...THE PROJECTED WEST AND SOUTHWEST
 TRACK OF ISIS MAY ALLOW FOR SOME REDEVELOPMENT AS IT CROSSES BACK
 INTO A BIT WARMER SST REGIME...BUT AT THIS TIME THE OFFICIAL
 INTENSITY FORECAST WILL ASSUME A GRADUAL WEAKENING TREND UNTIL THAT
 SCENARIO UNFOLDS.
  
 FORECASTER SISKO/JARVINEN
  
 FORECAST POSITIONS AND MAX WINDS
  
 INITIAL      16/0900Z 18.7N 132.3W    55 KT
  12HR VT     16/1800Z 18.7N 132.8W    50 KT
  24HR VT     17/0600Z 18.7N 133.3W    45 KT
  36HR VT     17/1800Z 18.6N 133.8W    40 KT
  48HR VT     18/0600Z 18.4N 134.2W    35 KT
  72HR VT     19/0600Z 18.3N 134.7W    30 KT
  96HR VT     20/0600Z 18.2N 135.1W    30 KT...DISSIPATING
 120HR VT     21/0600Z 18.1N 135.5W    30 KT...DISSIPATING
  
  
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