000
WTNT45 KNHC 260845
TCDAT5
TROPICAL STORM ERNESTO DISCUSSION NUMBER   7
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   AL052006
500 AM EDT SAT AUG 26 2006

AN AIR FORCE PLANE HAS BEEN INVESTIGATING ERNESTO AND FOUND THAT THE
CENTRAL PRESSURE DROPPED TO 999 MB WITH A WELL-ESTABLISHED
CYCLONIC CIRCULATION. HOWEVER FLIGHT LEVEL WINDS HAVE NOT INCREASED
MUCH SINCE THE PREVIOUS FLIGHT. IT APPEARS THAT THE CENTER IS
LOCATED ON THE WESTERN PORTION OF THE LARGE DEEP CONVECTIVE MASS
DUE TO THE CURRENT SOUTHWESTERLY WIND SHEAR. ALTHOUGH DVORAK
INTENSITY ESTIMATES SUPPORT 45 KNOTS...THE INITIAL INTENSITY IS
KEPT AT 40 KNOTS BASED ON AVAILABLE REPORTS FROM THE AIRCRAFT.
ERNESTO HAS BEEN A FIGHTER AND HAS BEEN ABLE TO SURVIVE THE STRONG
SHEAR SO FAR. UNANIMOUSLY...ALL GLOBAL MODELS DEVELOP AN
UPPER-LEVEL RIDGE OVER ERNESTO...A PATTERN WHICH IS CONDUCIVE FOR
STRENGTHENING. THIS UPPER-LEVEL PATTERN COMBINED WITH THE VERY WARM
WATERS AHEAD OF THE CYCLONE COULD LEAD TO SIGNIFICANT STRENGTHENING
OVER THE NEXT FEW DAYS. THIS COULD RESULT IN ERNESTO BECOMING A
POWERFUL HURRICANE IN THE GULF OF MEXICO. THE INTENSITY FORECAST IS
LOWER THAN THE GFDL AND VERY SIMILAR TO SHIPS AND FSU
SUPERENSEMBLE. OF COURSE...THE INTENSITY FORECAST IS HIGHLY
UNCERTAIN AND STRENGTHENING MAY NOT OCCUR AT ALL IF THE SHEAR DOES
NOT DECREASE.

FIXES FROM THE RECONNAISSANCE PLANE INDICATE THAT ERNESTO IS MOVING
TOWARD THE WEST-NORTHWEST OR 285 DEGREES AT 14 KNOTS AROUND THE
PERIPHERY OF THE SUBTROPICAL RIDGE. THIS GENERAL TRACK IS EXPECTED
TO CONTINUE THROUGH THE FORECAST PERIOD WITH A DECREASE IN FORWARD
SPEED IN A DAY OR TWO AS THE RIDGE TO THE NORTH WEAKENS. THE
OFFICIAL TRACK FORECAST IS IN THE MIDDLE OF THE MODEL ENVELOPE BUT
CLOSER TO THE GLOBAL MODEL CONSENSUS.

IN SUMMARY...ERNESTO COULD BECOME A POTENTIALLY DANGEROUS HURRICANE
AS IT MOVES ACROSS THE NORTHWESTERN CARIBBEAN SEA AND THE GULF OF
MEXICO. INTERESTS IN THESE AREAS SHOULD CLOSELY MONITOR THE
PROGRESS OF THIS SYSTEM.


FORECAST POSITIONS AND MAX WINDS

INITIAL      26/0900Z 14.8N  70.2W    40 KT
 12HR VT     26/1800Z 15.4N  72.2W    50 KT
 24HR VT     27/0600Z 16.6N  74.8W    55 KT
 36HR VT     27/1800Z 18.0N  77.5W    60 KT
 48HR VT     28/0600Z 19.5N  80.0W    70 KT
 72HR VT     29/0600Z 22.0N  83.5W    80 KT
 96HR VT     30/0600Z 24.0N  86.5W    90 KT
120HR VT     31/0600Z 26.0N  89.0W   100 KT

$$
FORECASTER AVILA