| 000 WTNT41 KNHC 122038 TCDAT1 HURRICANE IGOR DISCUSSION NUMBER 19 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL112010 500 PM AST SUN SEP 12 2010 IGOR CONTINUES TO INTENSIFY AT A RAPID PACE. DVORAK INTENSITY ESTIMATES AND THE UW-CIMSS ADT HAVE INCREASED FURTHER...AND THE INITIAL INTENSITY IS ADJUSTED SLIGHTLY UPWARD TO 120 KT BASED ON A COMPROMISE OF THESE DATA AND THE LATEST SATCON INTENSITY ESTIMATE. THE OFFICIAL INTENSITY FORECAST HAS ALSO BEEN ADJUSTED TO SHOW SOME FURTHER STRENGTHENING AND A PEAK INTENSITY AT DAY 3 OF 135 KT...SIMILAR TO SHIPS MODEL. FOR THE REMAINDER OF THE PERIOD...THE OFFICIAL FORECAST CALLS FOR SOME GRADUAL WEAKENING AND IS BASED PRIMARILY ON THE ICON CONSENSUS MODEL. IT IS WORTH NOTING THAT FLUCTUATIONS IN STRENGTH DUE TO EYEWALL REPLACEMENT CYCLES ARE POSSIBLE...HOWEVER...THERE IS LITTLE SKILL IN FORECASTING THE TIMING OF THESE CYCLES. THE INITIAL MOTION ESTIMATE REMAINS 270/12. THE TRACK FORECAST PHILOSOPHY REMAINS UNCHANGED FOR THIS ADVISORY...HOWEVER THERE IS STILL CONSIDERABLE DYNAMICAL MODEL SPREAD AFTER 36 HOURS. THE HWRF...UKMET AND ECMWF REMAIN TO THE LEFT OF THE CONSENSUS AND ARE SLIGHTLY SLOWER...WHILE THE OTHER REGIONAL AND GLOBAL MODELS SUGGEST A MORE PRONOUNCED WEAKNESS WITH TIME IN THE MID- TO UPPER-LEVEL RIDGE. THE NHC TRACK FORECAST IS NUDGED TO THE RIGHT OF THE PREVIOUS FORECAST AFTER DAY 3...CLOSER TO THE TVCN CONSENSUS MODEL...BUT STILL TO THE LEFT OUT OF RESPECT TO THE RELIABLE ECMWF MODEL. FORECAST POSITIONS AND MAX WINDS INITIAL 12/2100Z 17.7N 46.9W 120 KT 12HR VT 13/0600Z 17.8N 48.7W 125 KT 24HR VT 13/1800Z 18.1N 50.8W 125 KT 36HR VT 14/0600Z 18.7N 52.6W 130 KT 48HR VT 14/1800Z 19.4N 54.3W 130 KT 72HR VT 15/1800Z 21.3N 57.1W 135 KT 96HR VT 16/1800Z 23.5N 60.0W 125 KT 120HR VT 17/1800Z 25.8N 62.9W 120 KT |