[Tropical] Tropical Cyclone Discussion

[Nashville EMWIN]

WTNT44 KNHC 182033
TCDAT4
TROPICAL STORM DANIELLE DISCUSSION NUMBER  22
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
5 PM EDT WED AUG 18 2004

SATELLITE IMAGES CONTINUE TO SHOW THAT DANIELLE IS WEAKENING DUE
PRIMARILY TO SHEAR ASSOCIATED WITH A LARGE UPPER-LEVEL LOW TO ITS
WEST. THE LOW LEVEL CENTER IS WELL REMOVED FROM THE CONVECTION AND
THE CLOUD PATTERN HAS BECOME VERY POORLY ORGANIZED. THE CENTER OF
DANIELLE PASSED NEAR A DRIFTING BUOY WHICH MEASURED ONLY 1008.6 MB.
THEREFORE...THE INITIAL INTENSITY IS ADJUSTED TO 45 KNOTS AND THIS
APPEARS TO BE A GENEROUS ESTIMATE. THE SHEAR IS FORECAST TO REMAIN
HIGH SO WEAKENING IS EXPECTED. THIS IS CONSISTENT WITH THE SHIPS
MODEL.

DANIELLE HAS BEEN MOVING TOWARD THE NORTH-NORTHEAST OR 030 DEGREES
AT 9 KNOTS. STEERING CURRENTS ARE COLLAPSING AND THERE IS NO CHOICE
BUT TO FORECAST A REDUCTION IN FORWARD SPEED. THIS CONSISTENT WITH
MOST OF THE GLOBAL MODELS WHICH ARE MOVING THE CYCLONE SLOWER THAN
IN PREVIOUS RUNS.  THE OFFICIAL FORECAST CALLS FOR A SLOW
NORTHEASTWARD TRACK DURING THE NEXT 2 TO 3 DAYS WITH A GRADUAL
INCREASE IN FORWARD SPEED THEREAFTER. ON THIS TRACK...DANIELLE WILL
LIKELY BECOME EXTRATROPICAL IN 4 DAYS OR SO. ON THE OTHER HAND...IF
THE CYCLONE CONTINUES TO WEAKEN AND BECOMES A SHALLOW DEPRESSION OR
A REMNANT LOW...IT COULD MEANDER FOR A FEW DAYS PRODUCING
INTERMITTENT BURSTS OF CONVECTION. THE LATTER IS THE SOLUTION OF
THE GFS WHICH IS BY NO MEANS OUT OF THE QUESTION.

FORECASTER AVILA

FORECAST POSITIONS AND MAX WINDS

INITIAL      18/2100Z 29.3N  38.4W    45 KT
 12HR VT     19/0600Z 30.6N  38.2W    35 KT
 24HR VT     19/1800Z 32.0N  37.5W    30 KT
 36HR VT     20/0600Z 33.0N  36.5W    25 KT
 48HR VT     20/1800Z 33.5N  35.0W    25 KT
 72HR VT     21/1800Z 34.5N  32.0W    25 KT...EXTRATROPICAL
 96HR VT     22/1800Z 37.0N  28.0W    25 KT...EXTRATROPICAL
120HR VT     23/1800Z 40.0N  24.0W    25 KT...EXTRATROPICAL


$$
This weather bulletin was brought to you by:
www.nashvilleweather.net