540 
 WTNT42 KNHC 092031
 TCDAT2
 HURRICANE OTTO DISCUSSION NUMBER  15
 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   AL172010
 500 PM AST SAT OCT 09 2010
  
 SATELLITE IMAGES INDICATE THAT OTTO IS GRADUALLY WEAKENING. WARMING
 CLOUD TOPS ARE PRIMARILY LOCATED NORTH OF THE CIRCULATION CENTER AS
 A CONSEQUENCE OF CONTINUED MODERATE SOUTHWESTERLY SHEAR. HOWEVER...
 SATELLITE CLASSIFICATIONS SUPPORT MAINTAINING OTTO AS A HURRICANE
 FOR THIS ADVISORY. FURTHER WEAKENING IS FORECAST AS OTTO ENCOUNTERS
 A HIGH SHEAR ENVIRONMENT AND PASSES OVER PROGRESSIVELY COOLER
 WATERS DURING THE NEXT FEW DAYS. EXTRATROPICAL TRANSITION APPEARS
 TO BE UNDERWAY AS EVIDENCED BY CURRENT CONVECTIVE TRENDS AND
 COLDER...DRIER AIR IMPINGING ON THE CIRCULATION FROM THE WEST.
 GLOBAL MODELS INDICATE THAT THIS PROCESS SHOULD BE COMPLETE BY 36
 HOURS...ALTHOUGH IT COULD FINISH EARLIER. THE OFFICIAL NHC
 INTENSITY FORECAST IS ABOUT THE SAME AS THE PREVIOUS ONE AND IS IN
 LINE WITH THE SHIPS/LGEM GUIDANCE.
  
 OTTO IS STILL ACCELERATING...AND THE INITIAL MOTION ESTIMATE IS
 055/28. SOME FURTHER ACCELERATION TOWARD THE NORTHEAST IS LIKELY
 DURING THE NEXT 12-24 HOURS AS THE CYCLONE IS EMBEDDED IN A DEEP
 LAYER OF STRONG SOUTHWESTERLY FLOW AHEAD OF A LARGE MID-LATITUDE
 TROUGH OVER THE WESTERN ATLANTIC. AFTER 36 HOURS....OTTO SHOULD
 ABRUPTLY DECELERATE AND TURN EASTWARD AND THEN SOUTHEASTWARD AS IT
 STEERED AROUND THE CIRCULATION OF A DEEP LAYER CYCLONE OVER THE
 NORTHEAST ATLANTIC. THE MODEL GUIDANCE...EXCEPT FOR THE NOGAPS AND
 THE CANADIAN...IS IN GOOD AGREEMENT ON THIS SCENARIO...AND THE
 OFFICIAL TRACK FORECAST IS CLOSE TO THE PREVIOUS ONE AND THE
 MULTI-MODEL CONSENSUS.
 
  
 FORECAST POSITIONS AND MAX WINDS
  
 INITIAL      09/2100Z 32.4N  52.6W    65 KT
  12HR VT     10/0600Z 34.7N  47.6W    60 KT
  24HR VT     10/1800Z 38.0N  40.3W    55 KT
  36HR VT     11/0600Z 41.3N  33.6W    50 KT...POST-TROP/EXTRATROP
  48HR VT     11/1800Z 43.4N  29.4W    45 KT...POST-TROP/EXTRATROP
  72HR VT     12/1800Z 43.0N  25.5W    35 KT...POST-TROP/EXTRATROP
  96HR VT     13/1800Z 39.0N  24.0W    30 KT...POST-TROP/EXTRATROP
 120HR VT     14/1800Z 37.0N  22.0W    30 KT...POST-TROP/EXTRATROP
  
 $$
 FORECASTER KIMBERLAIN