000 WTNT41 KNHC 150257 TCDAT1 HURRICANE IGOR DISCUSSION NUMBER 28 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL112010 1100 PM AST TUE SEP 14 2010 CONVECTIVE CLOUD TOPS HAVE CONTINUED TO COOL...AND A SOLID WHITE RING ON THE DVORAK ENHANCEMENT HAS INTERMITTENTLY WRAPPED ENTIRELY AROUND THE EYE DURING THE PAST FEW HOURS. DVORAK T-NUMBERS WERE UP TO T7.0 FROM TAFB AND SAB AT 0000 UTC...AND T6.5 AND T7.0 FROM TWO FORMS OF THE UW-CIMSS ADT. SINCE THE WHITE RING DOES NOT ENTIRELY WRAP AROUND THE EYE AT THIS TIME...THE INITIAL INTENSITY IS BEING RAISED TO 135 KT. IGOR REMAINS OVER WARM WATERS AND IS IN AN ENVIRONMENT OF LOW VERTICAL SHEAR...SO THE OFFICIAL FORECAST MAINTAINS THIS INTENSITY FOR THE NEXT 12-24 HOURS. GRADUAL WEAKENING IS EXPECTED THEREAFTER WHEN IT IS LIKELY THAT INTERNAL DYNAMICS...WHICH ARE NOT WELL UNDERSTOOD...WILL INFLUENCE THE INTENSITY. THE OFFICIAL FORECAST IS VERY CLOSE TO A CONSENSUS OF THE STATISTICAL AND DYNAMICAL GUIDANCE THROUGH DAY 4 BUT IS A LITTLE HIGHER THAN THAT GUIDANCE AT DAY 5 TO MAINTAIN CONTINUITY WITH THE PREVIOUS PACKAGE. IGOR IS MOVING AT 295/8. THE HURRICANE HAS REACHED THE SOUTHWESTERN PERIPHERY OF THE SUBTROPICAL RIDGE...AND IT SHOULD MAKE A TURN TOWARD THE NORTHWEST SOON. THE TRACK GUIDANCE IS IN GOOD AGREEMENT FOR THE FIRST 3-4 DAYS BUT THEN SHOWS MORE DIVERGENCE ON DAY 5 WITH THE GFDL WELL TO THE NORTHEAST OF BERMUDA AND THE ECMWF WELL TO THE SOUTHWEST OF BERMUDA. THE OFFICIAL FORECAST LIES VERY CLOSE TO THE CONSENSUS THROUGH THE FORECAST PERIOD AND ENDED UP BEING SIMILAR TO THE PREVIOUS FORECAST. REGARDLESS OF WHERE IGOR ENDS UP IN 5 DAYS...THE LARGE WIND FIELD OF THE HURRICANE IS EXPECTED TO BE VERY CLOSE TO OR NEAR BERMUDA WITHIN THE NEXT 3 TO 4 DAYS. INTERESTS ON BERMUDA SHOULD CONTINUE TO MONITOR THE PROGRESS OF IGOR. FORECAST POSITIONS AND MAX WINDS INITIAL 15/0300Z 19.0N 53.9W 135 KT 12HR VT 15/1200Z 19.8N 55.0W 135 KT 24HR VT 16/0000Z 20.7N 56.4W 130 KT 36HR VT 16/1200Z 21.7N 58.0W 125 KT 48HR VT 17/0000Z 22.8N 59.6W 125 KT 72HR VT 18/0000Z 25.5N 63.0W 115 KT 96HR VT 19/0000Z 29.0N 65.0W 105 KT 120HR VT 20/0000Z 33.5N 65.5W 95 KT $$ FORECASTER BERG