Tropical Storm IKE

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TROPICAL STORM IKE DISCUSSION NUMBER   4
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   AL092008
500 AM EDT TUE SEP 02 2008
 
THE STRUCTURE OF IKE HAS NOT CHANGED SIGNIFICANTLY THIS EVENING WITH 
SUBSTANTIAL CONVECTIVE BANDING EMBEDDED IN A LARGE SURFACE
CIRCULATION.  THE DVORAK CLASSIFICATIONS FROM TAFB AND SAB REMAIN
3.0 OR 45 KT...WHICH IS THE CURRENT INTENSITY.  

AN AMSU PASS AT 0020Z PROVIDED SOME CONFIDENCE IN ESTIMATING A TRACK
AT 280 DEGREES AT 13 KT.  THE TROPICAL STORM WILL BE MOVING BRISKLY
OFF TOWARD THE WEST OR WEST-NORTHWEST UNDER THE INFLUENCE OF A DEEP
LAYERED SUBTROPICAL RIDGE TO ITS NORTH.  AS THE CUTOFF LOW CURENTLY
SOUTH OF NOVA SCOTIA KICKS OUT TO THE NORTHEAST...THE SUBTROPICAL
RIDGE SHOULD RETROGRADE TOWARD THE WEST OVER THE NEXT FEW DAYS.  A
MOTION WESTWARD ACROSS THE SUBTROPICAL NORTH ATLANTIC ALONG ABOUT
20N WOULD BE SOMEWHAT UNUSUAL...BUT IS SUPPORTED BY OUR MOST
RELIABLE TRACK MODELS.  THE TRACK MODEL GUIDANCE IS IN A RELATIVELY
TIGHT CLUSTER SLIGHTLY TO THE SOUTH OF THE PREVIOUS MODEL RUNS. 
THIS TRACK FORECAST IS A BLEND BETWEEN THE MORE SOUTHERLY MODEL
CONSENSUS AND THE MORE NORTHERLY PREVIOUS OFFICIAL FORECAST.
 
THE INTENSITY PREDICTION IS MORE PROBLEMATIC.  IN THE NEAR
TERM...IKE IS IN A CONDUCIVE DYNAMICAL ENVIRONMENT WITH LOW
VERTICAL SHEAR AND DIVERGENCE ALOFT...BUT THE THERMODYNAMICS ARE
NOT AS FAVORABLE FOR DEVELOPMENT WITH ONLY SLIGHTLY WARM SSTS AND A
POCKET OF LOW-LEVEL DRY AIR TO ITS SOUTH.  IN THE LONGER TERM...THE
OCEAN TEMPERATURES SHOULD WARM TO 29C...BUT THE SHEAR SHOULD
INCREASE AS FLOW BETWEEN AN UPPER LOW EAST OF IKE AND THE UPPER
RIDGE NORTHWEST OF IKE IS PREDICTED TO PRODUCE 30 KT
NORTHEASTERLIES.  GRADUAL INTENSIFICATION IS INDICATED THROUGH THE
PERIOD...WHICH REFLECTS THE CONSENSUS OF THE SHIPS AND LGEM MODELS
CALLING FOR A MINIMAL HURRICANE...AND THE GFDL AND HWRF MODELS
WHICH SUGGEST A MUCH STRONGER CYCLONE.  THIS INTENSITY FORECAST IS
NEARLY THE SAME AS PROVIDED IN THE PREVIOUS ADVISORY.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      02/0900Z 18.6N  43.1W    45 KT
 12HR VT     02/1800Z 19.0N  45.3W    55 KT
 24HR VT     03/0600Z 19.6N  48.2W    60 KT
 36HR VT     03/1800Z 20.2N  51.3W    70 KT
 48HR VT     04/0600Z 20.8N  54.3W    75 KT
 72HR VT     05/0600Z 21.5N  60.5W    80 KT
 96HR VT     06/0600Z 21.5N  66.5W    85 KT
120HR VT     07/0600Z 21.5N  72.0W    90 KT
 
$$
FORECASTER LANDSEA/PASCH
 
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