kromdog
(Weather Hobbyist)
Sun Aug 26 2012 02:59 PM
Re: Tropical Storm/Hurricane Issac - 26/12Z Upper Air Analysis

2PM NOAA Discussion

THE TRACK FORECAST BEYOND DAY 2 HAS BECOME PROBLEMATIC. DYNAMICAL
MODELS DEPICT THE CYCLONE MOVING INTO A BREAK IN THE SUBTROPICAL
RIDGE NORTH OF THE GULF COAST IN ABOUT 72 HOURS. HOWEVER THERE IS
A LARGE SPREAD AMONG THE MORE RELIABLE TRACK MODELS. FOR EXAMPLE...
THE ECMWF FORECAST IS ABOUT 300 N MI EAST OF THE GFS SOLUTION AT DAY
3. SINCE THE DYNAMICAL MODEL CONSENSUS HAS SHIFTED WESTWARD...THE
OFFICIAL TRACK FORECAST IS MOVED A BIT TO THE WEST OF THE PREVIOUS
ONE. THIS REQUIRES AN EXTENSION OF THE HURRICANE WATCH WESTWARD
ALONG THE LOUISIANA COAST. IT SHOULD BE NOTED THAT THERE IS
GREATER THAN USUAL UNCERTAINTY IN THE TRACK FORECAST.