916 
 WTNT42 KNHC 240247
 TCDAT2
 HURRICANE KARL DISCUSSION NUMBER  30
 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
 11 PM EDT THU SEP 23 2004
  
 KARL IS NOW EXPERIENCING STRONG SOUTHWESTERLY SHEAR AND THE
 LOW-LEVEL CENTER IS BECOMING DETACHED FROM THE MORE OBVIOUS
 MID-LEVEL CIRCULATION. AS SUCH...THE INITIAL POSITION IS BECOMING
 MORE UNCERTAIN. CI NUMBERS HAVE FALLEN TO 5.5...5.0...AND 4.0 FROM
 TAFB...SAB...AND AFWA SO THE INITIAL INTENSITY IS SET AT A
 COMPROMISE OF 80 KT. A DRIFTING BUOY NEAR THE CENTER REPORTED A
 PRESSURE OF 963 MB...WHICH WOULD NORMALLY SUPPORT A STRONGER
 TROPICAL CYCLONE...BUT THIS PRESSURE-WIND RELATIONSHIP IS ALLOWABLE
 FOR A HIGH-LATITUDE STORM. THE CLOUD PATTERN SUGGESTS THAT KARL IS
 IN THE FIRST STAGES OF EXTRATROPICAL TRANSITION...WHICH SHOULD BE
 COMPLETED WITHIN THE NEXT 12-24 HOURS AS THE SYSTEM BECOMES
 ENVELOPED WITHIN THE BELT OF STRONG WESTERLIES SOUTH OF GREENLAND.
 THE OFFICIAL INTENSITY FORECAST CLOSELY FOLLOWS THE GFDL...WHICH
 SEEMS TO HAVE BEEN CORRECTLY FORECASTING THE HURRICANE'S RECENT
 INTENSITY TRENDS. THIS IS SLIGHTLY HIGHER THAN THE SHIPS GUIDANCE.
  
 KARL IS STILL ACCELERATING WITH AN INITIAL MOTION OF 020/26. THE
 SYSTEM WILL CONTINUE MOVING IN A NORTH-NORTHEASTWARD DIRECTION FOR
 THE NEXT 24 HOURS BUT WILL THEN MAKE A RAPID TURN TO THE NORTHEAST
 AS IT MOVES INTO THE STRONG UPPER LEVEL WESTERLIES. THE OFFICIAL
 FORECAST TRACK IS A TAD TO THE WEST OF THE PREVIOUS TRACK AFTER 24
 HOURS...DUE TO A WESTWARD SHIFT IN THE MODEL CONSENSUS. KARL IS
 EXPECTED TO MERGE WITH ANOTHER EXTRATROPICAL LOW NORTH OF THE
 BRITISH ISLES BY 72 HOURS.
  
 FORECASTER BERG/AVILA
  
 FORECAST POSITIONS AND MAX WINDS
  
 INITIAL      24/0300Z 38.7N  41.5W    80 KT
  12HR VT     24/1200Z 42.6N  40.9W    75 KT...BECOMING EXTRATROPICAL
  24HR VT     25/0000Z 47.5N  39.4W    65 KT...EXTRATROPICAL
  36HR VT     25/1200Z 52.2N  35.4W    55 KT...EXTRATROPICAL
  48HR VT     26/0000Z 57.0N  27.0W    50 KT...EXTRATROPICAL
  72HR VT     27/0000Z...MERGED WITH ANOTHER EXTRATROPICAL LOW
  
  
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