707 
 WTNT41 KNHC 160855
 TCDAT1
 HURRICANE IGOR DISCUSSION NUMBER  33
 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   AL112010
 500 AM AST THU SEP 16 2010
  
 MICROWAVE AND INFRARED SATELLITE IMAGERY SUGGEST THAT THE EYEWALL
 REPLACEMENT WITH IGOR IS COMPLETE.   THE NEW EYEWALL APPEARS TO BE
 CONSOLIDATING AT A RADIUS OF ABOUT 30-35 N MI AND IS PRODUCING
 RATHER DEEP CONVECTION...SUGGESTING THE INTENSITY IS INCREASING
 AGAIN. A BLEND OF THE SATELLITE ESTIMATES GIVES AN INITIAL
 INTENSITY OF 125 KT.
  
 A LARGE-SCALE ENVIRONMENT OF LIGHT SHEAR AND WARM WATER IS FAVORABLE
 FOR THE MAINTENANCE OF AN EXTREMELY DANGEROUS HURRICANE FOR THE
 NEXT FEW DAYS. THE EXACT INTENSITY OF IGOR WILL BE PRIMARILY
 DICTATED BY EYEWALL CYCLES...WHICH ARE WELL BEYOND OUR FORECAST
 ABILITIES. THE MAJORITY OF THE MODEL GUIDANCE INDICATES THAT SLOW
 WEAKENING IS THE MOST LIKELY SOLUTION...AND THE NHC FORECAST REFLECT
 THIS. HOWEVER...IT IS MORE IMPORTANT TO RECOGNIZE THAT ALL OF THE
 GUIDANCE...AND THE NHC FORECAST...KEEPS IGOR AS A LARGE AND
 DANGEROUS HURRICANE FOR THE NEXT SEVERAL DAYS.
  
 THE INITIAL MOTION IS AN UNSTEADY 300/6.  IGOR IS EXPECTED TO MOVE
 SLOWLY AROUND THE WESTERN PERIPHERY OF A SUBTROPICAL RIDGE OVER THE
 CENTRAL ATLANTIC.  WEAK TROUGHING ALONG ABOUT 70W SHOULD RECURVE
 THE CYCLONE IN 3 OR 4 DAYS.  THE MAIN DIFFERENCE IN THE MODELS IS
 HOW QUICKLY IGOR ACCELERATES TO THE NORTHEAST IN THE MID-LATITUDES. 
 SINCE THE TROUGHING OVER THE WESTERN ATLANTIC IS RATHER FLAT...
 THERE HAS BEEN A TREND IN THE MODELS TO SHOW WEAKER FLOW NEAR
 IGOR...AND CONSEQUENTLY DELAY THE INCREASE IN FORWARD SPEED.  THE
 OFFICIAL FORECAST IS A BIT SLOWER THAN THE PREVIOUS ONE...
 ESPECIALLY AT THE END OF THE PERIOD.  WITH REGARDS TO HOW CLOSE
 IGOR COMES TO BERMUDA...THE ECMWF IS NOW THE MOST EASTERN MODEL
 AFTER BEING THE WESTERNMOST YESTERDAY.  THIS APPEARS TO BE DUE TO
 THAT MODEL SHOWING A SLIGHTLY WEAKER RIDGE TODAY...WHICH ALLOWS
 IGOR TO GAIN A LITTLE MORE LATITUDE EARLY ON AND EVENTUALLY PASS A
 LITTLE FARTHER EAST OF BERMUDA.  HOWEVER...ALL OF THE GUIDANCE IS
 WELL CLUSTERED ON A TRACK CLOSE TO THAT ISLAND...AND LITTLE CHANGE
 HAS BEEN MADE TO THE OFFICIAL TRACK NEAR BERMUDA.  SINCE THIS IS
 SUCH A LARGE HURRICANE...SIGNIFICANT IMPACTS ARE EXPECTED ON
 BERMUDA...BUT IT IS TOO EARLY TO TELL HOW CLOSE THE CORE OF THE
 HURRICANE...AND THE STRONGEST WINDS...WILL COME TO THAT ISLAND. 
  
 SO FAR...NOAA BUOY 41044 HAS REPORTED A PEAK 1-MINUTE WIND OF 45
 KT...GUSTING TO 56 KT...ALONG WITH A MINIMUM PRESSURE OF 995
 MB...AND A SIGNIFICANT WAVE HEIGHT OF 29 FT.  HOWEVER...THE WORST
 IS YET TO COME FOR THAT STATION...AS IGOR WILL MOVE VERY CLOSE TO
 THE BUOY TONIGHT. 
  
 FORECAST POSITIONS AND MAX WINDS
  
 INITIAL      16/0900Z 20.5N  56.8W   125 KT
  12HR VT     16/1800Z 21.1N  57.8W   125 KT
  24HR VT     17/0600Z 22.0N  59.4W   125 KT
  36HR VT     17/1800Z 23.2N  61.1W   120 KT
  48HR VT     18/0600Z 24.7N  62.7W   120 KT
  72HR VT     19/0600Z 28.0N  65.0W   110 KT
  96HR VT     20/0600Z 32.5N  64.5W    95 KT
 120HR VT     21/0600Z 37.5N  59.0W    80 KT
  
 $$
 FORECASTER BLAKE