Tropical Storm DORIAN

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TROPICAL STORM DORIAN DISCUSSION NUMBER   2
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL042013
1100 AM EDT WED JUL 24 2013
 
VISIBLE SATELLITE IMAGERY AND RECENT ASCAT SCATTEROMETER WINDS
INDICATE THAT THE TROPICAL DEPRESSION HAS BECOME BETTER ORGANIZED
AND HAS STRENGTHENED INTO TROPICAL STORM DORIAN. THE INITIAL
INTENSITY OF 45 KT IS BASED ON A 38-KT ASCAT SURFACE WIND AT
1111Z... AND VARIOUS OBJECTIVE SATELLITE INTENSITY ESTIMATES OF
ABOUT 45 KT.

THE INITIAL MOTION ESTIMATE IS 285/18 KT. DORIAN IS EXPECTED TO BE
STEERED WEST-NORTHWESTWARD TO WESTWARD BY A STRONG DEEP-LAYER
SUBTROPICAL RIDGE OVER THE CENTRAL AND EASTERN ATLANTIC. THE NHC
MODEL GUIDANCE REMAINS TIGHTLY PACKED IN EXCELLENT AGREEMENT ON
THIS TRACK SCENARIO...WITH THE ONLY DIFFERENCES BEING SLIGHT
VARIATIONS IN THE FORWARD SPEED. THE NHC OFFICIAL FORECAST TRACK IS
SIMILAR TO THE PREVIOUS ADVISORY AND IS CLOSE TO THE MULTI-MODEL
CONSENSUS TVCN.
 
FOR THE NEXT 24 HOURS OR SO...THE VERTICAL SHEAR IS FORECAST TO BE
VERY LOW WHILE DORIAN REMAINS OVER MARGINALLY WARM SSTS. HOWEVER...
DURING THE 24-48 HOUR TIME PERIOD...DORIAN WILL BE MOVING OVER 25C
SSTS...WHICH COULD INDUCE SOME SLIGHT WEAKENING. THE CYCLONE IS
EXPECTED TO MAINTAIN THE CURRENT FAVORABLE EQUATORIAL INFLOW OF
WARM UNSTABLE AIR THAT IS OFFSETTING THE COOLER MORE STABLE AIR
BEING INGESTED FROM THE NORTH...AND THAT COULD OFFSET THE EFFECTS
OF DORIAN PASSING OVER COOLER WATERS. FOR THAT REASON...THE
INTENSITY FORECAST ONLY SHOWS SLIGHT WEAKENING AT 36- AND 48-HOURS. 
AFTER THAT...THE CYCLONE IS LIKELY TO ENCOUNTER BOTH WARMER WATER
AND INCREASING WESTERLY SHEAR...SO THE INTENSITY FORECAST IS HELD
STEADY. THE OFFICIAL INTENSITY FORECAST IS SLIGHTLY HIGHER THAN THE
PREVIOUS ADVISORY THROUGH THE NEXT 24 HOURS DUE TO THE HIGHER
INITIAL INTENSITY...BUT THEN FOLLOWS THE TREND OF CONSENSUS MODELS.
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  24/1500Z 14.3N  29.9W   45 KT  50 MPH
 12H  25/0000Z 15.0N  32.6W   50 KT  60 MPH
 24H  25/1200Z 15.8N  36.1W   50 KT  60 MPH
 36H  26/0000Z 16.4N  39.8W   45 KT  50 MPH
 48H  26/1200Z 17.1N  43.4W   40 KT  45 MPH
 72H  27/1200Z 18.3N  51.2W   40 KT  45 MPH
 96H  28/1200Z 19.3N  58.2W   40 KT  45 MPH
120H  29/1200Z 20.1N  64.0W   40 KT  45 MPH
 
$$
FORECASTER STEWART
 
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