064
WTNT42 KNHC 120846
TCDAT2
TROPICAL STORM FRED DISCUSSION NUMBER 19
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL072009
500 AM AST SAT SEP 12 2009
SATELLITE IMAGES INDICATE THAT FRED HAS SHEARED APART THIS MORNING
AS THE LOW-LEVEL CIRCULATION IS EXPOSED WITH THE NEAREST CONVECTION
AT LEAST 90 N MI FROM THE CENTER. A 0358Z AQUA MICROWAVE PASS
SHOWED BELIEVABLE WINDS OF 40-45 KT...AND ASSUMING SOME SPIN DOWN
OF THE CIRCULATION SINCE THEN...THE INITIAL WIND SPEED IS LOWERED
TO 40 KT. THERE IS NO REASON TO FORECAST ANYTHING BUT CONTINUED
WEAKENING DUE TO STRONG SHEAR...MARGINAL WATER TEMPERATURES AND A
DRY MID-LEVEL ENVIRONMENT. FRED WILL LIKELY BECOME A REMNANT LOW
WITHIN 36 HOURS...IF NOT SOONER. THERE IS A REMOTE CHANCE OF
REGENERATION IN THE LONG-TERM AS THE GLOBAL MODELS WEAKEN THE SHEAR
AND THE SYSTEM MOVES OVER WARMER WATERS. HOWEVER...THERE PROBABLY
WILL NOT BE MUCH LEFT OF FRED AT THAT TIME TO TAKE ADVANTAGE OF THE
ENVIRONMENTAL CONDITIONS.
THE TROPICAL CYCLONE HAS NOT BEEN MOVING MUCH DURING THE PAST FEW
HOURS...AND LITTLE MOTION IS EXPECTED DURING THE NEXT 12-24 HOURS
AS STEERING CURRENTS REMAIN WEAK. THEREAFTER FRED...OR THE REMNANTS
THEREOF...IS EXPECTED TO TURN TOWARD THE NORTH...NORTHWEST...AND
WEST-NORTHWEST AND ACCELERATE AS RIDGING REBUILDS OVER THE CENTRAL
ATLANTIC. BESIDES THE UKMET MODEL...WHICH HAS DISPLAYED A
SOUTHWARD BIAS FOR THIS STORM...THE REST OF THE GUIDANCE IS IN GOOD
AGREEMENT ON THIS PATH. THE NHC FORECAST IS BASICALLY AN UPDATE OF
THE PREVIOUS FORECAST AND IS CLOSE TO THE MODEL CONSENSUS.
FORECAST POSITIONS AND MAX WINDS
INITIAL 12/0900Z 17.8N 33.6W 40 KT
12HR VT 12/1800Z 18.0N 33.6W 35 KT
24HR VT 13/0600Z 18.6N 33.9W 30 KT
36HR VT 13/1800Z 19.5N 35.5W 25 KT...REMNANT LOW
48HR VT 14/0600Z 20.5N 37.5W 25 KT...REMNANT LOW
72HR VT 15/0600Z 22.5N 42.5W 20 KT...REMNANT LOW
96HR VT 16/0600Z 24.0N 48.0W 20 KT...REMNANT LOW
120HR VT 17/0600Z 25.5N 53.5W 20 KT...REMNANT LOW
FORECASTER BLAKE
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