347 
 WTNT44 KNHC 232059
 TCDAT4
 TROPICAL STORM IVAN DISCUSSION NUMBER  71
 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
 5 PM EDT THU SEP 23 2004
  
 AFTER THE EARLIER A BURST OF CONVECTION...THUNDERSTORM ACTIVITY HAS
 DWINDLED AND THE WIND HAVE DECREASED ACCORDINGLY. THE INITIAL
 INTENSITY OF 40 KT AND A PRESSURE OF 1003 MB IS BASED ON THE LAST
 RECON REPORT AROUND 17Z.
  
 THE INITIAL MOTION ESTIMATE IS 310/07. THERE IS NO SIGNIFICANT
 CHANGE TO THE PREVIOUS FORECAST REASONING. IVAN SHOULD CONTINUE TO
 MOVE NORTHWESTWARD TO WEST-NORTHWESTWARD AND BE INLAND WITHIN THE
 NEXT 12 HOURS OVER SOUTHWESTERN LOUISIANA OR THE UPPER-TEXAS COAST.
 AFTERWARDS...RAPID WEAKENING WILL RESULT IN THE LOW-LEVEL
 CIRCULATION DECOUPLING FROM THE MID- AND UPPER-LEVEL CIRCULATIONS.
 THIS SHOULD ALLOW THE LOW-LEVEL CIRCULATION TO BE STEERED SLOWLY
 WEST AND THEN SOUTHWESTWARD BY A LARGE LOW-LEVEL RIDGE/HIGH THAT IS
 FORECAST TO BUILD EASTWARD OVER THE CENTRAL AND SOUTHERN PLAINS
 BEHIND A COLD FRONT. THE TRACK SCENARIO REMAINS CONSISTENT WITH THE
 SHALLOW BAM MODEL AND MOST OF THE GLOBAL MODELS. WHILE A FEW MODELS
 TAKE THE LOW-LEVEL CIRCULATION BACK OVER THE GULF OF MEXICO IN
 36-48 HOURS...STRONG SOUTHWESTERLY UPPER-LEVEL WINDS OF MORE THAN
 40 KT SHOULD PREVENT ANY REDEVELOPMENT FROM OCCURRING.
  
 WHILE IVAN IS NOT EXPECTED TO BE A PROLIFIC WIND PRODUCER...ITS SLOW
 FORWARD SPEED FOR THE NEXT SEVERAL DAYS MAY BRING UP LARGE AMOUNTS
 OF GULF MOISTURE THAT COULD RESULT IN LOCALLY HEAVY RAINFALL.
  
 FORECASTER STEWART
  
 FORECAST POSITIONS AND MAX WINDS
  
 INITIAL      23/2100Z 29.4N  93.0W    40 KT
  12HR VT     24/0600Z 30.0N  94.1W    35 KT...INLAND
  24HR VT     24/1800Z 30.4N  95.0W    30 KT...INLAND
  36HR VT     25/0600Z 30.2N  95.7W    25 KT...INLAND
  48HR VT     25/1800Z 29.6N  96.4W    20 KT...DISSIPATING INLAND
  72HR VT     26/1800Z 28.8N  97.2W    20 KT...REMNANT LOW INLAND
  96HR VT     27/1800Z...DISSIPATED INLAND
  
  
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