000 WTNT41 KNHC 160242 TCDAT1 HURRICANE IGOR DISCUSSION NUMBER 32 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL112010 1100 PM AST WED SEP 15 2010 BASED ON RECENT MICROWAVE DATA...IGOR APPEARS TO BE COMPLETING AN EYEWALL REPLACEMENT. IN ADDITION...INFRARED GEOSTATIONARY SATELLITE IMAGERY SHOWS THE INNER CORE CONVECTION DIMINISHING WITH AN OUTER RING OF CONVECTION BECOMING MORE PROMINENT. DVORAK ESTIMATES FROM TAFB REMAIN AT T6.0/6.5 AND HAVE FALLEN TO T5.0/5.5 FROM SAB...AND THE LATEST ADT ESTIMATE IS T6.3. THE INITIAL INTENSITY IS HELD AT 115 KT FOR THIS ADVISORY. IGOR IS EXPECTED TO REMAIN IN AN ENVIRONMENT OF LOW SHEAR FOR THE NEXT 60 HOURS OR SO...AND LITTLE CHANGE IN INTENSITY IS EXPECTED DURING THAT TIME. FLUCTUATIONS IN INTENSITY ARE STILL POSSIBLE HOWEVER...ESPECIALLY IF THE NEW OUTER EYEWALL CONTRACTS OVER THE NEXT COUPLE OF DAYS. BY DAYS 3 THROUGH 5...SOUTHERLY SHEAR IS EXPECTED TO INCREASE AND SHOULD INDUCE SOME WEAKENING. THE INTENSITY GUIDANCE IS IN FAIRLY GOOD AGREEMENT DURING THAT TIME...AND THE OFFICIAL FORECAST WILL SHOW WEAKENING TO CATEGORY 1 OR 2 STRENGTH BY DAYS 4 AND 5. IGOR IS MOVING 295 DEGREES AT 8 KT. THE HURRICANE IS LOCATED NEAR THE SOUTHWESTERN PERIPHERY OF A MID-LEVEL RIDGE OVER THE CENTRAL ATLANTIC AND IS BEING INCREASINGLY INFLUENCED BY A LARGE BUT FLAT MID- TO UPPER-LEVEL TROUGH NEAR THE U.S. EAST COAST. SINCE THE TROUGH IS NOT THAT SHARP...IGOR IS EXPECTED TO MAINTAIN ITS CURRENT MOTION FOR THE NEXT 36 HOURS OR SO. IT SHOULD THEN BEGIN TO TURN MORE SHARPLY ON DAYS 3 THROUGH 5...WITH ITS CENTER PASSING NEAR BERMUDA IN ABOUT 96 HOURS. THE TRACK GUIDANCE IS TIGHTLY CLUSTERED BUT DOES SHOW SOME SPEED DIFFERENCES BY DAY 5. THE OFFICIAL FORECAST IS JUST A LITTLE TO THE WEST OF THE MODEL CONSENSUS TVCN SINCE THE USUALLY-RELIABLE ECMWF LIES ON THE WESTERN SIDE OF THE GUIDANCE ENVELOPE. FORECAST POSITIONS AND MAX WINDS INITIAL 16/0300Z 20.2N 56.5W 115 KT 12HR VT 16/1200Z 20.8N 57.6W 115 KT 24HR VT 17/0000Z 21.7N 59.2W 115 KT 36HR VT 17/1200Z 22.6N 60.8W 115 KT 48HR VT 18/0000Z 24.0N 62.6W 115 KT 72HR VT 19/0000Z 27.5N 65.0W 105 KT 96HR VT 20/0000Z 31.5N 65.0W 95 KT 120HR VT 21/0000Z 36.5N 60.5W 80 KT $$ FORECASTER BERG