|
Show Selection: |
| #375518 (Received by flhurricane at: 11:05 AM 12.Sep.2010) TCDAT1 HURRICANE IGOR DISCUSSION NUMBER 17 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL112010 1100 AM AST SUN SEP 12 2010 CONVENTIONAL AND MICROWAVE IMAGERY SHOWS THAT IGOR IS GOING THROUGH A PERIOD OF RAPID INTENSIFICATION. VISIBLE IMAGERY DEPICTS A CLEARING EYE AND INFRARED IMAGERY AND AN SSMIS OVERPASS REVEAL AN INTENSE FULLY-DEVELOPED INNER RING OF DEEP CONVECTION. THE OUTFLOW HAS BECOME QUITE IMPRESSIVE...PARTICULARLY OVER THE EASTERN PORTION OF THE CYCLONE WHERE THE COLDEST CLOUD TOPS RESIDE. THE INITIAL INTENSITY OF 90 KT IS BASED ON A COMPROMISE OF SATELLITE INTENSITY ESTIMATES OF 77 AND 90 KT FROM SAB AND TAFB...RESPECTIVELY...A UW-CIMSS ADT OF 107 KT...AND A SATELLITE CONSENSUS OF 86 KT...THAT INCLUDES A BLEND OF AMSU MICROWAVE ESTIMATES. THE INTENSITY FORECAST HAS BEEN ADJUSTED UPWARD FROM THE PREVIOUS FORECAST TO ACCOUNT FOR THE RI TREND...AND INDICATES STRENGTHENING TO A MAJOR HURRICANE IN 12 HOURS...WITH FURTHER INTENSIFICATION TO A CATEGORY FOUR HURRICANE BY DAY 2. THE FORECAST IS BASED ON THE ICON CONSENSUS BUT IS HEDGED A BIT MORE TOWARD THE SHIPS AND LGEM BEYOND 48 HOURS. THE INITIAL MOTION IS ESTIMATED TO BE 270/11...WITHIN THE DEEP-LAYER EASTERLY FLOW OF THE SUBTROPICAL RIDGE NORTH OF IGOR. THE LARGE- SCALE MODELS SUGGEST THAT A DEVELOPING WEAKNESS IN THE RIDGE OVER THE WESTERN ATLANTIC WILL RESULT IN A WEST-NORTHWESTWARD TURN IN ABOUT 36 HOURS. AFTERWARD...A TURN TOWARD THE NORTHWEST IS INDICATED AS IGOR ROUNDS THE SOUTHWESTERN PERIPHERY OF THE RIDGE AND MOVES INTO THE WEAKNESS. THERE IS CONSIDERABLE SPREAD IN THE DYNAMICAL MODEL GUIDANCE BEYOND DAY 2. A CLUSTER THAT INCLUDES THE GFDL...THE GFS AND THE GEFS ENSEMBLE MEAN SUGGESTS A WEAKER RIDGE AND AN EARLIER TURN TOWARD THE NORTHWEST. THE OFFICIAL FORECAST IS BASED ON PRIMARILY ON THE TVCN MULTI-MODEL CONSENSUS BUT IS ADJUSTED SLIGHTLY TO THE LEFT OF THE PREVIOUS ADVISORY BEYOND DAY 3 AND CLOSER TO THE UKMET...ECMWF...AND THE ECMWF ENSEMBLE MEAN. FORECAST POSITIONS AND MAX WINDS INITIAL 12/1500Z 17.7N 45.7W 90 KT 12HR VT 13/0000Z 17.8N 47.5W 105 KT 24HR VT 13/1200Z 18.0N 49.8W 110 KT 36HR VT 14/0000Z 18.4N 51.8W 115 KT 48HR VT 14/1200Z 19.0N 53.6W 115 KT 72HR VT 15/1200Z 20.7N 56.7W 125 KT 96HR VT 16/1200Z 22.6N 59.6W 125 KT 120HR VT 17/1200Z 24.5N 62.5W 125 KT $$ FORECASTER ROBERTS/BRENNAN |
