630 
 WTNT41 KNHC 212032
 TCDAT1
 HURRICANE IGOR DISCUSSION NUMBER  55
 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   AL112010
 500 PM AST TUE SEP 21 2010
  
 LAND AND BUOY OBSERVATIONS IN NEWFOUNDLAND AND THE ADJACENT WATERS
 INDICATE THAT IGOR HAS BECOME FULLY EMBEDDED WITHIN A FRONTAL ZONE.
 JUST AFTER THE CENTER OF IGOR PASSED OVER CANADIAN BUOY 44251 NEAR
 CAPE RACE EARLIER IN THE DAY...THE TEMPERATURE DROPPED BY ABOUT 10
 DEGREES F.  HOWEVER...THE CYCLONE IS STILL PRODUCING HURRICANE-
 FORCE WINDS...AND THE INITIAL INTENSITY OF 70 KT IS BASED ON
 REPORTED SUSTAINED WINDS OF 63 KT AT BONAVISTA NEWFOUNDLAND.  IGOR
 IS EXPECTED TO CONTINUE TO PRODUCE HURRICANE-FORCE WINDS FOR
 ANOTHER DAY OR SO...AND THEN SHOULD GRADUALLY WEAKEN AS IT MOVES
 NORTHWARD INTO THE DAVIS STRAITS.
  
 THE INITIAL MOTION IS ESTIMATED TO BE 25 DEGREES AT 34 KT.  THE
 TRACK GUIDANCE CONTINUES TO BE IN RELATIVELY GOOD AGREEMENT IN
 SHOWING IGOR TURNING NORTHWESTWARD TO THE WEST OF GREENLAND IN A
 COUPLE OF DAYS AND INTERACTING WITH ANOTHER AREA OF LOW PRESSURE
 NEAR NORTHERN QUEBEC.  THE MODELS DO SHOW VARYING SOLUTIONS...
 HOWEVER...ON WHICH OF THESE TWO SYSTEMS WILL BECOME THE DOMINANT
 ONE.  THE OFFICIAL FORECAST...IN ACCORDANCE WITH GUIDANCE
 PROVIDED BY THE OCEAN PREDICTION CENTER...WILL KEEP IGOR AS A
 DISTINCT CYCLONE THROUGH 96 HOURS.  THE OFFICIAL FORECAST INDICATES
 VERY LITTLE MOTION FROM 72 TO 96 HOURS SINCE THE CYCLONE WILL BE
 NORTH OF THE BELT OF STRONG WESTERLIES BY THEN.
 
 THE 12-FT SEAS RADII PROVIDED BY THE OCEAN PREDICTION CENTER ARE 480
 NE...900 SE...1320 SW...AND 380 NW.  RADII IN THE FORECAST/ADVISORY
 ARE LIMITED TO 995 N MI...BUT 12-FT SEAS ARE ACTUALLY OCCURRING AT
 A GREATER DISTANCE THAN THAT.
  
 FORECAST POSITIONS AND MAX WINDS
  
 INITIAL      21/2100Z 49.3N  51.7W    70 KT...POST-TROP/EXTRATROP
  12HR VT     22/0600Z 53.0N  49.8W    70 KT...POST-TROP/EXTRATROP
  24HR VT     22/1800Z 57.2N  51.0W    70 KT...POST-TROP/EXTRATROP
  36HR VT     23/0600Z 61.6N  57.5W    55 KT...POST-TROP/EXTRATROP
  48HR VT     23/1800Z 62.5N  60.5W    45 KT...POST-TROP/EXTRATROP
  72HR VT     24/1800Z 62.0N  60.5W    40 KT...POST-TROP/EXTRATROP
  96HR VT     25/1800Z 61.5N  59.5W    40 KT...POST-TROP/EXTRATROP
 120HR VT     26/1800Z...DISSIPATED
  
 $$
 FORECASTER BERG