624 
 WTNT43 KNHC 220832
 TCDAT3
 TROPICAL STORM LISA DISCUSSION NUMBER  12
 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
 5 AM EDT WED SEP 22 2004
 
 THE SYSTEM CONTINUES AS A RATHER SMALL...AMORPHOUS...BLOB OF DEEP
 CONVECTION ON SATELLITE IMAGES.  ALTHOUGH THE CLOUD TOPS ARE VERY
 COLD...THERE IS LITTLE ORGANIZATION OTHER THAN A CONCENTRATION NEAR
 THE CENTER.  BASED ON DVORAK CLASSIFICATIONS... THE INTENSITY IS
 ADJUSTED DOWNWARD SLIGHTLY.  THERE IS SOME CONCERN ABOUT HOW THE
 EVOLUTION OF THE STORM WILL BE AFFECTED BY THE DISTURBANCE TO ITS
 EAST-SOUTHEAST.  THE LATTER SYSTEM COULD ALSO BECOME A TROPICAL
 CYCLONE...AND WOULD PROBABLY BE A LARGER ONE THAN LISA.  THUS IT IS
 POSSIBLE THAT THE LARGER SYSTEM COULD ABSORB LISA.  OTHERWISE THE
 ENVIRONMENT IS MARGINALLY FAVORABLE FOR STRENGTHENING.  THE
 OFFICIAL FORECAST SHOWS SOME STRENGTHENING BUT IS BELOW THE SHIPS
 GUIDANCE BEYOND 2 DAYS BECAUSE OF THE POTENTIALLY UNFAVORABLE
 INFLUENCE OF THE SYSTEM TO THE EAST.
 
 IT IS NOT EASY TO LOCATE THE CENTER...BUT...BECAUSE OF THE MODERATE
 EAST-NORTHEASTERLY SHEARING ENVIRONMENT...IT IS ESTIMATED TO BE
 NEAR THE EASTERN EDGE OF THE DENSE OVERCAST.  THE INITIAL MOTION IS
 ESTIMATED TO BE 285/6.  TRACK GUIDANCE IS FAR FROM 
 STRAIGHTFORWARD...WITH CONSIDERABLE SCATTER AMONG THOSE DYNAMICAL
 MODELS THAT ARE ABLE TO TRACK A CENTER IN THEIR FORECAST FIELDS. 
 THE GFDL MODEL SHOWS A SHARP SOUTHWARD TURN FOLLOWED BY A SHARP
 NORTHWARD TURN.  THE NOGAPS SHOWS ERRATIC MOTION...AND THE GFS
 LOSES THE VORTEX IN ITS OUTPUT.  ONLY THE U.K. MET OFFICE MODEL
 TRACK IS SOMEWHAT CLIMATOLOGICAL...SINCE IT DEPICTS A GRADUAL TURN
 TO THE NORTHWEST.  THAT DOES NOT SEEM TO BE AN UNREASONABLE
 SCENARIO...SINCE I DO NOT EXPECT LISA TO HAVE MUCH OF A MID-LEVEL
 RIDGE TO ITS NORTH OVER THE NEXT SEVERAL DAYS.  GIVEN THE
 UNCERTAINTIES AND DIVERGENCE IN THE MODEL OUTPUT...THE OFFICIAL
 FORECAST IS EVEN SLOWER THAN THE PREVIOUS ONE.
  
 FORECASTER PASCH
  
 FORECAST POSITIONS AND MAX WINDS
  
 INITIAL      22/0900Z 14.5N  41.2W    55 KT
  12HR VT     22/1800Z 14.8N  42.0W    55 KT
  24HR VT     23/0600Z 15.2N  43.2W    55 KT
  36HR VT     23/1800Z 15.6N  44.3W    60 KT
  48HR VT     24/0600Z 15.8N  45.0W    65 KT
  72HR VT     25/0600Z 16.5N  46.5W    70 KT
  96HR VT     26/0600Z 17.5N  48.0W    70 KT
 120HR VT     27/0600Z 18.5N  49.0W    70 KT
  
 $$