111 
 WTNT43 KNHC 212101
 TCDAT3
 TROPICAL STORM LISA DISCUSSION NUMBER  10
 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
 5 PM EDT TUE SEP 21 2004
  
 LISA REMAINS A VERY COMPACT TROPICAL CYCLONE AND...AS SUCH...IS
 SUBJECT TO RAPID FLUCTUATIONS IN INTENSITY. THIS MAY HAVE BEEN THE
 CASE EARLIER TODAY AS AN SSMI OVERPASS INDCIATED THE MID-LEVEL
 CIRCULATION/EYE FEATURE BECAME DISPLACED A LITTLE TO THE SOUTHWEST
 OF THE LOW-LEVEL CENTER. THIS HAS RESULTED IN SIGNIFICANT
 DIFFERENCES IN THE SATELLITE POSITION ESTIMATES. THE INITIAL
 POSITION IS BETWEEN THE TWO CIRCULATION CENTERS. HOWEVER...DURING
 THE PAST FEW HOURS A BURST OF DEEP CONVECTION...TOPS COLDER THAN
 -80C...HAS DEVELOPED INTO A CDO-LIKE FEATURE OVER THE OLDER
 LOW-LEVEL CENTER LOCATED FARTHER TO THE EAST. THE INTENSITY REMAINS
 UNCHANGED AT 60 KT...WHICH IS ONLY SLIGHTLY HIGHER THAN THE DVORAK
 INTENSITY ESTIMATE OF T3.5...OR 55 KT...FROM TAFB.
  
 THE INITIAL MOTION ESTIMATE IS NOW 285/07.  ONCE AGAIN...THERE
 REMAINS NO SIGNIFICANT CHANGE TO THE PREVIOUS FORECAST TRACK OR
 REASONING. MOST OF THE GLOBAL MODELS EITHER LOSE LISA WITHIN 24
 HOURS...OR QUICKLY TURN THE CYCLONE NORTHWEST AND THEN NORTHWARD
 LIKE THE NOGAPS AND UKMET MODELS ARE INDICATING. HOWEVER...THOSE
 TWO MODELS HAVE HAD A PERSISTENT RIGHT-OF-TRACK BIAS THE PAST 24
 HOURS SINCE THEY HAVE NOT HANDLED THE RIDGE BETWEEN KARL AND LISA
 VERY WELL. WHILE THE AFOREMENTIONED RIDGE IS NARROW...IT IS STRONG
 TO KEEP VERY SMALL LISA MOVING WEST TO WEST-NORTHWESTWARD. IN
 ADDITION...A LARGE TROPICAL DISTURBANCE LOCATED A FEW HUNDRED MILES
 SOUTHEAST OF LISA IS EXPECTED TO INDUCE SOME SOUTHWARD COMPONENT OF
 MOTION AS THAT DISTURBANCE CONTINUES TO LIKELY GROW AND INTENSITY.
 THE GFDL HAS BEEN THE ONLY MODEL TO CONSISTENTLY PICK UP ON THIS
 INTERACTION AND IT FORCES LISA SHARPLY SOUTHWARD IN 48 HOURS. WHILE
 THE SPECIFICS OF THE GFDL TRACK ARE LIKELY OVERDONE...ITS
 CONSISTENT TREND IN MOVING LISA SOUTHWARD CAN NOT BE IGNORED. A
 SLIGHT SOUTHWARD BEND IN THE TRACK IS INDICATED BY THE OFFICIAL
 FORECAST. THIS IS ALSO CONSISTENT WITH ALL THE GLOBAL MODELS
 FORECASTING A RIDGE TO BUILD OVER AND TO THE EAST OF THE LEEWARD
 ISLANDS BY 96-120 HOURS.
 
 DUE TO THE VERY SMALL SIZE OF LISA...NO SIGNIFICANT INTENSITY
 INCREASES ARE FORECAST...EVEN THOUGH RAPID FLUCTUATIONS ARE
 CERTAINLY POSSIBLE.
  
 FORECASTER STEWART
  
 FORECAST POSITIONS AND MAX WINDS
  
 INITIAL      21/2100Z 14.4N  40.3W    60 KT
  12HR VT     22/0600Z 14.8N  41.5W    60 KT
  24HR VT     22/1800Z 15.2N  43.0W    60 KT
  36HR VT     23/0600Z 15.2N  44.5W    65 KT
  48HR VT     23/1800Z 15.0N  45.7W    65 KT
  72HR VT     24/1800Z 15.0N  47.0W    70 KT
  96HR VT     25/1800Z 15.5N  48.5W    75 KT
 120HR VT     26/1800Z 17.5N  50.5W    75 KT
  
  
 $$