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Tropical Storm MELISSA (Text)

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TROPICAL STORM MELISSA DISCUSSION NUMBER   8
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   AL142007
500 AM EDT SUN SEP 30 2007
 
STRONG WESTERLY SHEAR IS GETTING THE BEST OF MELISSA AND THE
LOW-LEVEL CIRCULATION RECENTLY BECAME EXPOSED.  NEW CONVECTION HAS 
FORMED NEAR THE CIRCULATION CENTER BUT IS ALREADY SHOWING SIGNS OF
BEING SHUNTED EASTWARD.  BASED ON THE DEGRADED SATELLITE
PRESENTATION...THE INITIAL INTENSITY IS LOWERED TO 35 KT.  WITH THE
SHEAR EXPECTED TO INCREASE AND THE SSTS EXPECTED TO DECREASE IN A
DAY OR SO...MELISSA COULD STRUGGLE TO GENERATE PERSISTENT DEEP
CONVECTION AND MAINTAIN ITS STATUS AS A TROPICAL CYCLONE. 
DEGENERATION TO A REMNANT LOW IS EXPECTED IN ABOUT 3 DAYS...IF NOT
SOONER. 
 
MELISSA HAS PICKED UP FORWARD SPEED WITH THE INITIAL MOTION ESTIMATE
NOW 295/11.  THE TRACK FORECAST IS STRONGLY DEPENDENT ON HOW LONG
MELISSA CAN MAINTAIN APPRECIABLE VERTICAL DEPTH.  THE DYNAMICAL
MODELS ARE ESSENTIALLY SPLIT INTO TWO CAMPS.  THE NOGAPS AND UKMET
MODELS SHOW MELISSA REMAINING A RELATIVELY DEEP CYCLONE WITH A
SHARP NORTHEASTWARD TURN BEYOND 48 HOURS IN RESPONSE TO A MIDDLE- TO
UPPER-LEVEL TROUGH EXPECTED TO DEVELOP OVER THE CENTRAL ATLANTIC. 
THE WEAKER AND SHALLOWER HWRF AND ECMWF SOLUTIONS FOR THE CYCLONE
SHOW AN ALMOST INSTANT TURN WESTWARD.  SINCE THE OFFICIAL FORECAST
ASSUMES MELISSA WILL BE ABLE TO GENERATE INTERMITTENT BURSTS OF
CONVECTION DURING THE NEXT DAY OR TWO...THE TRACK FORECAST LIES IN
BETWEEN THESE TWO SCENARIOS BUT IS SOUTH OF THE DYNAMICAL MODEL
CONSENSUS. 
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      30/0900Z 16.5N  31.4W    35 KT
 12HR VT     30/1800Z 17.2N  33.0W    35 KT
 24HR VT     01/0600Z 18.3N  35.1W    30 KT
 36HR VT     01/1800Z 19.3N  37.1W    30 KT
 48HR VT     02/0600Z 20.5N  39.2W    30 KT
 72HR VT     03/0600Z 23.0N  42.5W    25 KT...REMNANT LOW
 96HR VT     04/0600Z 26.0N  44.5W    20 KT...REMNANT LOW
120HR VT     05/0600Z...DISSIPATED
 
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