931 
 WTPZ42 KNHC 112035
 TCDEP2
 TROPICAL DEPRESSION ISIS DISCUSSION NUMBER  15
 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
 2 PM PDT SAT SEP 11 2004
  
 VISIBLE AND ENHANCED INFRARED ANIMATION DEPICT THAT THE PARTIALLY
 EXPOSED LOW-LEVEL CIRCULATION CENTER OF ISIS HAS TUCKED IN BENEATH
 THE NORTHEASTERN EDGE OF A NEW BURST OF DEEP CONVECTION. IMAGERY
 ALSO SHOWS A DEVELOPING BANDING FEATURE WRAPPING IN FROM THE WEST
 QUADRANT. SATELLITE CURRENT INTENSITY ESTIMATES ARE 35 KT FROM TAFB
 AND 30 KT FROM AFWA AND SAB.  WE WILL WAIT TO SEE IF THE BANDING
 FEATURES BECOME BETTER DEFINED BEFORE RE-UPGRADING ISIS TO A
 TROPICAL STORM. THE SHIPS AND NOW THE GFDL SHOW A GRADUAL
 INTENSIFICATION TREND THROUGH 72 HOURS BEFORE LEVELING OFF.
 UW-CIMSS WIND SHEAR ANALYSIS CONTINUES TO SHOW 10 TO 20 KT OF
 EASTERLY SHEAR...HOWEVER...LARGE SCALE MODELS AND THE INTENSITY
 GUIDANCE SUGGESTS THAT THE SHEAR WILL WEAKEN. THE FORECAST
 INTENSITY IS SIMILAR TO THE PREVIOUS FORECAST AND AGREES WITH THE
 SHIPS AND THE GFDL.
  
 THE INITIAL MOTION IS WESTWARD OR 270/8. GLOBAL AND REGIONAL MODELS
 ARE IN GOOD AGREEMENT ON THE STRENGTH AND ORIENTATION OF A
 MID-UPPER RIDGE EXTENDING FROM MEXICO/BAJA THROUGH 48 HOURS.
 AFTERWARDS...A DEEPENING MID-UPPER LEVEL TROUGH EXTENDING SOUTHWEST
 FROM BAJA IS EXPECTED TO CAUSE A SLIGHT REDUCTION IN MOTION BEYOND
 THE 72 HOUR PERIOD. THE OFFICIAL FORECAST IS SIMILAR TO THE
 PREVIOUS FORECAST AND IS BASED OFF OF GUNA AND THE CONU CONSENSUS. 
 
 FORECASTER ROBERTS/PASCH
  
 FORECAST POSITIONS AND MAX WINDS
  
 INITIAL      11/2100Z 17.5N 120.8W    30 KT
  12HR VT     12/0600Z 17.5N 122.2W    35 KT
  24HR VT     12/1800Z 17.5N 124.2W    35 KT
  36HR VT     13/0600Z 17.5N 126.1W    40 KT
  48HR VT     13/1800Z 17.5N 127.9W    45 KT
  72HR VT     14/1800Z 17.5N 131.0W    45 KT
  96HR VT     15/1800Z 17.5N 132.5W    45 KT
 120HR VT     16/1800Z 17.5N 134.5W    45 KT
  
 $$