[Tropical] Tropical Cyclone Discussion

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WTNT41 KNHC 161506
TCDAT1
HURRICANE JEANNE DISCUSSION NUMBER  12
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
11 AM EDT THU SEP 16 2004

AIRCRAFT AND DROPSONDE DATA THIS MORNING INDICATED THAT JEANNE
REACHED HURRICANE STRENGTH NEAR THE EASTERN TIP OF HISPANIOLA.
PEAK FLIGHT-LEVEL WINDS OF 88 KT...AND MULTIPLE DROPSONDE SURFACE
ESTIMATES BETWEEN 63 AND 69 KT SUPPORT THE 70 KT INITIAL INTENSITY
ESTIMATE.

OVER THE PAST 12 HOURS JEANNE HAS BEEN MOVING 275/6.  JEANNE IS
SOUTH OF A MID-LEVEL RIDGE THAT SHOULD PRODUCE A GENERALLY
WEST-NORTHWESTWARD MOTION OVER THE NEXT COUPLE OF DAYS...AND MODEL
GUIDANCE IS VERY TIGHTLY CLUSTERED OVER THIS INTERVAL.  AFTER THAT
THERE IS CONSIDERABLE UNCERTAINTY DEPENDING ON THE EVOLUTION OF THE
MID-LEVEL REMNANTS OF IVAN...WHICH COULD BE ANWHERE FROM THE
TENNESSEE VALLEY TO CAPE HATTERAS IN THREE DAYS.  THE MORE EASTERN
SOLUTIONS RESULT IN A MORE NORTHERLY TRACK OF JEANNE THROUGH 5
DAYS...AS INDICATED BY THE GFS AND UKMET.  MORE WESTWARD
TRACKS...TOWARD FLORIDA...ARE INDICATED BY THE GFDL...ECMWF...AND
FSU SUPERENSEMBLE.  STEERING CURRENTS ARE EXPECTED TO BECOME WEAK
IN ABOUT 48 HOURS AND IT IS NOT YET POSSIBLE TO CONFIDENTLY CHOOSE
BETWEEN THE SCENARIOS OUTLINED ABOVE.  THE OFFICIAL FORECAST LIES A
LITTLE TO THE LEFT OF THE MODEL CONSENSUS...AND REPRESENTS A
COMPROMISE BETWEEN THE EXTREMES OF THE GFS AND GFDL GUIDANCE.  IT
IS QUITE CURIOUS THAT THE SUPERENSEMBLE 5-DAY POINT LIES TO THE
LEFT OF ALL OF ITS COMPONENTS...BUT THIS CAN HAPPEN GIVEN THE WAY
THAT BIAS-CORRECTING MODEL IS CONSTRUCTED.

JEANNE SHOULD WEAKEN BELOW HURRICANE STRENGTH OVER HISPANIOLA...BUT
EVENTUALLY SHOULD COME UNDER LIGHT ANTICYCLONIC FLOW ASSOCIATED
WITH THE REMNANTS OF IVAN.  THIS...AND THE WARM WATERS OF THE
BAHAMAS...SHOULD ALLOW RESTRENGTHENING.  THE OFFICIAL FORECAST IS
CLOSE TO THE GFDL AND SHIPS GUIDANCE.

FORECASTER FRANKLIN

FORECAST POSITIONS AND MAX WINDS

INITIAL      16/1500Z 18.8N  68.7W    70 KT
 12HR VT     17/0000Z 19.3N  70.0W    60 KT
 24HR VT     17/1200Z 20.2N  71.7W    55 KT
 36HR VT     18/0000Z 21.1N  73.4W    65 KT
 48HR VT     18/1200Z 22.0N  75.0W    70 KT
 72HR VT     19/1200Z 23.5N  76.5W    85 KT
 96HR VT     20/1200Z 26.5N  78.0W    85 KT
120HR VT     21/1200Z 30.0N  79.5W    85 KT


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