[Tropical] Tropical Cyclone Discussion

[Nashville EMWIN]

WTNT42 KNHC 120915
TCDAT2
TROPICAL STORM BONNIE DISCUSSION NUMBER  17
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
5 AM EDT THU AUG 12 2004

THE STRUCTURAL CHANGES MENTIONED EARLIER HAVE CONTINUED LEAVING THE
MAXIMUM WINDS IN A BAND OF CONVECTION AWAY FROM THE CENTER.  THE
SYSTEM CONTINUES TO BE VERTICALLY SHEARED. SO FAR...THE
LATEST RECONNAISSANCE FLIGHT HAS REPORTED A CENTRAL PRESSURE OF
1010 MB AND MAXIMUM SURFACE WINDS OF 37 KT.  ON THE OTHER
HAND...SATELLITE INTENSITY ESTIMATES ARE 55 KT FROM TAFB
AND 45 KT FROM SAB AND AFWA...SUGGESTING THE AIRCRAFT MIGHT NOT
HAVE SAMPLED THE STRONGEST WINDS.  THE INITIAL INTENSITY IS
DECREASED TO 45 KT.

BONNIE NOW APPEARS TO BE ACCELERATING TOWARD THE NORTHEAST AS HAS
BEEN ANTICIPATED. THE INITIAL MOTION IS 045/14.  THE TRACK FORECAST
IS STRAIGHTFORWARD.  BONNIE IS EMBEDDED IN SOUTHWESTELY FLOW
ASSOCIATED WITH AN UNSEASONABLY STRONG DEEP LAYER TROUGH OVER THE
CENTRAL UNITED STATES.  THE CYCLONE SHOULD CONTINUE TO ACCELERATE
NORTHEASTWARD ON THE EAST SIDE OF THE TROUGH...MAKING LANDFALL OVER
THE FLORIDA PANHANDLE THURSDAY AFTERNOON AND THEN MOVING THROUGH
THE EASTERN UNITED STATES.  ALL TRACK GUIDANCE AGREES WITH THIS
SCENARIO...AND THE TRACK FORECAST IS IN AGREEMENT WITH THE
CONCENSUS...WHICH IS A LITTLE TO THE LEFT OF THE PREVIOUS OFFICIAL
FORECAST.

THE STEADILY INCREASING VERTICAL SHEAR SUGGESTS THAT THE WINDOW OF
OPPORTUNITY FOR STRENGTHENING IS OVER. HOWEVER...THE CYCLONE HAS
JUST GENERATED BURSTS OF CONVECTION TO THE EAST AND SOUTHEAST OF
THE CENTER.  EVEN SO IT WILL NOT BE ABLE TO DEEPEN ENOUGH TO REACH
HURRICANE INTENSITY BEFORE LANDFALL.  THE INTENSITY FORECAST WILL
KEEP THE SYSTEM INVARIANT AT 45 KTS UNTIL LANDFALL...BUT SOME
FLUCTUATIONS ARE POSSIBLE.  AFTER LANDFALL... BONNIE SHOULD WEAKEN
AND BECOME EXTRATROPICAL.

BASED UPON THE ABOVE THE HURRICANE WARNINGS AND WATCHES HAVE BEEN
DISCONTINUED.

FORECASTER JARVINEN

FORECAST POSITIONS AND MAX WINDS

INITIAL      12/0900Z 28.4N  87.5W    45 KT
 12HR VT     12/1800Z 30.4N  85.6W    45 KT...INLAND
 24HR VT     13/0600Z 35.1N  81.1W    40 KT...INLAND
 36HR VT     13/1800Z 40.8N  76.5W    35 KT...INLAND...EXTRATROPICAL
 48HR VT     14/0600Z 47.0N  72.0W    35 KT...INLAND...EXTRATROPICAL
 72HR VT     15/0600Z 56.2N  59.2W    35 KT...INLAND...EXTRATROPICAL



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