Tropical Storm NADINE

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TROPICAL STORM NADINE DISCUSSION NUMBER  11
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL142012
1100 PM AST THU SEP 13 2012
 
THE SATELLITE PRESENTATION OF NADINE HAS NOT CHANGED MUCH OVER THE
PAST FEW HOURS...AS THE CLOUD PATTERN IS CHARACTERIZED BY A
CDO-LIKE PATTERN WITH NO EVIDENCE OF AN EYE. THE INITIAL INTENSITY
REMAINS 60 KT BASED ON A BLEND OF THE LATEST DVORAK ESTIMATES FROM
TAFB AND SAB AND RECENT ADT ESTIMATES. THE SIGNALS FOR THE
INTENSITY FORECAST ARE MIXED. RECENT WATER VAPOR IMAGERY SHOWS THAT
THE OUTFLOW HAS BECOME A LITTLE BETTER ESTABLISHED OVER THE PAST
FEW HOURS. HOWEVER...SATELLITE ANALYSIS FROM UW-CIMSS SUGGEST THAT
SOUTHWESTERLY SHEAR OF 10 TO 15 KT IS AFFECTING NADINE...WHICH IS
CONSISTENT WITH MICROWAVE IMAGERY THAT SHOWS THE LOW-LEVEL CENTER
LOCATED SOUTH-SOUTHWEST OF THE DEEP CONVECTION. WHILE THE SHIPS
MODEL SHOWS THE SHEAR INCREASING OVER THE CYCLONE IN THE NEXT DAY
OR TWO...MOST OF THE GUIDANCE NOW SHOWS NADINE BECOMING A HURRICANE
BY 36 HOURS. LATER IN THE PERIOD...THE CYCLONE MAY BE IN A SLIGHTLY
MORE FAVORABLE ENVIRONMENT OF MODERATE SOUTHWESTERLY SHEAR OVER
WARM SSTS. MOST OF THE GUIDANCE HAS TRENDED UPWARD THIS CYCLE...AND
THE INTENSITY FORECAST HAS BEEN ADJUSTED IN THAT DIRECTION AT DAYS
3 THROUGH 5. THE NHC FORECAST IS CLOSE TO THE SHIPS AND LGEM
GUIDANCE BUT IS BELOW THE LATEST INTENSITY CONSENSUS MODELS.
 
THE INITIAL MOTION ESTIMATE IS 330/13...AS NADINE IS NOW SITUATED ON
THE SOUTHWESTERN PERIPHERY OF A WEAKENING MID-LEVEL RIDGE. THE
OVERALL TRACK FORECAST REASONING IS UNCHANGED...AS NADINE WILL MOVE
AROUND THE RIDGE IN THE NEXT 24 TO 36 HOURS AND THEN TURN EAST-
NORTHEASTWARD OR EASTWARD IN THE MID-LATITUDE WESTERLIES. THE
GUIDANCE IS TIGHTLY CLUSTERED THROUGH ABOUT 48 HOURS...AND THE NHC
FORECAST IS LARGELY AN UPDATE OF THE PREVIOUS ONE THROUGH THAT
TIME. A LARGE SPREAD PERSISTS IN THE TRACK MODELS AT DAYS 3 THROUGH
5. THE GFS...ECMWF...AND FSU SUPERENSEMBLE ARE ON THE SOUTHERN EDGE
OF THE GUIDANCE SUITE WHILE THE GFDL CONTINUES TO BE A FAR LEFT
OUTLIER SHOWING NADINE TURNING NORTHWARD AFTER 3 DAYS. THE NHC
TRACK LATE IN THE PERIOD IS SOUTH OF THE TVCA MULTI-MODEL CONSENSUS
AND NORTH OF THE AFOREMENTIONED SOUTHERNMOST MODEL GROUP. THROUGH
MOST OF THE PERIOD THE NHC FORECAST IS ALSO A LITTLE FASTER THAN THE
PREVIOUS...FOLLOWING THE LEAD OF THE GFS AND ECMWF MODELS.
  
FORECAST POSITIONS AND MAX WINDS
 
INIT  14/0300Z 25.0N  53.7W   60 KT  70 MPH
 12H  14/1200Z 26.8N  54.2W   60 KT  70 MPH
 24H  15/0000Z 29.1N  54.0W   60 KT  70 MPH
 36H  15/1200Z 30.7N  52.7W   65 KT  75 MPH
 48H  16/0000Z 31.4N  50.4W   65 KT  75 MPH
 72H  17/0000Z 32.3N  44.6W   70 KT  80 MPH
 96H  18/0000Z 33.5N  38.5W   70 KT  80 MPH
120H  19/0000Z 35.5N  32.5W   70 KT  80 MPH
 
$$
FORECASTER BRENNAN
 
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