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
 
$$
FORECASTER ROBERTS/BRENNAN