[Tropical] Tropical Cyclone Discussion

[EMWIN Server]

WTNT41 KNHC 211446
TCDAT1
HURRICANE JEANNE DISCUSSION NUMBER  32
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
11 AM EDT TUE SEP 21 2004

SATELLITE IMAGERY AND INTENSITY ESTIMATES INDICATE JEANNE HAS
CHANGED LITTLE SINCE THE LAST RECON FLIGHT EARLIER THIS MORNING.
THE RAGGED EYE HAS BECOME CLOUD COVERED DURING THE PAST FEW HOURS
AND THE SATELLITE INTENSITY ESTIMATE IS A CONSENSUS T4.5...OR 77KT
...FROM ALL THREE AGENCIES. THEREFORE...THE INTENSITY REMAINS 80 KT
FOR THIS ADVISORY.

THE INITIAL MOTION IS NOW 105/06.  THERE REMAINS NO SIGNIFICANT
CHANGE TO THE PREVIOUS FORECAST TRACK OR REASONING. ALL OF THE NHC
MODEL GUIDANCE...EXCEPT FOR THE GFS...INDICATES JEANNE SHOULD
CONTINUE TO SLOWLY TURN SOUTHEAST AND EVEN SOUTHWARD DURING THE
NEXT 12-24 HOURS AS A DEEP-LAYERED HIGH PRESSURE RIDGE BUILDS TO
THE NORTH. THIS ALREADY APPEARS TO BE UNDERWAY AS WATER VAPOR
IMAGERY INDICATES A LARGE TROUGH TO THE NORTHEAST OF JEANNE...THAT
IS ACCELERATING HURRICANE KARL NORTHWARD...HAS BEEN PUSHING
EASTWARD. BEHIND THE TROUGH...THE MID- TO UPPER-LEVEL FLOW HAS
BECOME NORTHERLY...ALBEIT STRONGLY DIFLUENT. THIS NORTHERLY FLOW
SHOULD ACT TO STEER JEANNE SOUTHWARD FOR THE NEXT DAY OR SO...
FOLLOWED BY A TURN BACK TOWARD THE WEST AND WEST-NORTHWEST AS THE
HIGH/RIDGE SHIFTS EASTWARD OFF THE U.S. EAST COAST. THE OFFICIAL
FORECAST TRACK IS CLOSE TO THE PREVIOUS TRACK THROUGH ABOUT 72
HOURS...AND THEN A LITTLE TO THE LEFT OF THAT WHICH IS SIMILAR TO
THE GUNS CONSENSUS...SINCE THE GFS REMAINS AN EASTERN OUTLIER
MODEL. THE UKMET...GFDL...AND DEEP BAM MODELS ARE FASTER THAN AND
MORE TO THE LEFT OF THE OFFICIAL TRACK...BUT I WOULD PREFER TO WAIT
UNTIL THE 12Z MODELS...CONTAINING NEW UPPER-AIR DATA...COME IN
BEFORE MAKING ANY SIGNIFICANT TRACK CHANGES.

THE VERTICAL SHEAR ACROSS JEANNE IS FORECAST TO WEAKEN TO LESS THAN
10 KT IN THE 36-48 HOURS PERIOD...SO SOME SLIGHT STRENGTHENING IS
FORECAST TO OCCUR DURING THAT TIME. AFTERWARDS...INCREASING SHEAR
FROM THE SOUTH AND SOUTHWEST AROUND THE WESTERN PERIPHERY OF A
LARGE 200 MB ANTICYCLONE SHOULD BRING ABOUT GRADUAL WEAKENING.
HOWEVER...IF JEANNE MOVES FASTER AND FARTHER WEST LIKE SOME OF THE
MODELS ARE INDICATING...THEN JEANNE WILL WEAKEN EVEN MORE THAN
INDICATED SINCE THE CYCLONE WOULD ENCOUNTER GREATER SHEAR DUE TO
45-55 KT 200 MB WINDS FORECAST TO BE NEAR THE SOUTHEAST U.S. COAST.

FORECASTER STEWART

FORECAST POSITIONS AND MAX WINDS

INITIAL      21/1500Z 27.5N  69.3W    80 KT
 12HR VT     22/0000Z 27.1N  69.2W    80 KT
 24HR VT     22/1200Z 26.6N  69.4W    80 KT
 36HR VT     23/0000Z 26.4N  69.9W    85 KT
 48HR VT     23/1200Z 26.4N  70.7W    85 KT
 72HR VT     24/1200Z 26.8N  72.0W    85 KT
 96HR VT     25/1200Z 27.5N  73.5W    75 KT
120HR VT     26/1200Z 29.5N  74.5W    65 KT


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