000
WTNT44 KNHC 240243
TCDAT4
 
TROPICAL STORM NADINE DISCUSSION NUMBER  46
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL142012
1100 PM AST SUN SEP 23 2012

DEEP CONVECTION IS NOT VERY ABUNDANT IN ASSOCIATION WITH THE STORM
AND IT IS OCCURRING MAINLY OVER THE NORTHERN SEMICIRCLE OF THE
CIRCULATION.  THE CURRENT INTENSITY IS MAINTAINED AT 50 KT IN
AGREEMENT WITH THE UNIVERSITY OF WISCONSIN CIMSS TC INTENSITY
CONSENSUS...SATCON...WHICH IS A BLEND OF OBJECTIVE DVORAK AND
MICROWAVE ESTIMATES.  THE STORM IS CURRENTLY LOCATED IN A MARGINAL
ATMOSPHERIC ENVIRONMENT...WITH ABOUT 25 KT OF WEST-SOUTHWESTERLY
SHEAR AND DRY MID-LEVEL AIR INFLUENCING THE CIRCULATION.  THE
DYNAMICAL GUIDANCE INDICATES THAT THE ATMOSPHERE WILL SOON BECOME
MORE CONDUCIVE FOR STRENGTHENING.  GLOBAL MODELS SHOW A 200 MB
TROUGH TO THE WEST OF NADINE CUTTING OFF AND SHIFTING SOUTHWARD IN
A DAY OR SO...WITH A SMALL UPPER-LEVEL RIDGE DEVELOPING OVER THE
TROPICAL CYCLONE.  THE SHIPS/LGEM GUIDANCE SHOW THE SHEAR
DIMINISHING SUBSTANTIALLY IN 36-48 HOURS.  THUS...ASSUMING THAT
NADINE IS ABLE TO GENERATE ENOUGH DEEP CONVECTION TO SURVIVE AS A
TROPICAL CYCLONE OVER THE NEXT DAY OR SO...THE SYSTEM HAS AN
OPPORTUNITY TO STRENGTHEN.  THE OFFICIAL INTENSITY FORECAST IS
CLOSE TO THE PREVIOUS ONE AND IS NOT FAR FROM THE INTENSITY MODEL
CONSENSUS.

NADINE HAS BEEN DRIFTING WEST-NORTHWESTWARD AND THE INITIAL MOTION
IS NEAR 290/3.  THE TRACK FORECAST REASONING REMAINS MORE OR LESS
UNCHANGED FROM THE PREVIOUS ADVISORY.  A STRONG MID-TROPOSPHERIC
ANTICYCLONE CURRENTLY LOCATED TO THE NORTHWEST OF NADINE IS
FORECAST TO EVOLVE INTO A NORTHEAST- TO SOUTHWEST-ORIENTED RIDGE
OVER THE NEXT SEVERAL DAYS.  THIS STEERING PATTERN SHOULD CAUSE THE
TROPICAL CYCLONE TO TURN WESTWARD TO WEST-SOUTHWESTWARD THROUGH
ABOUT 72 HOURS.  LATE IN THE FORECAST PERIOD...A WEAKNESS IS LIKELY
TO DEVELOP IN THE RIDGE TO THE NORTH AND NORTHWEST OF THE CYCLONE. 
AS A RESULT...NADINE IS FORECAST TO TURN TOWARD THE NORTHWEST BY
DAY 5.  THE OFFICIAL FORECAST TRACK IS SIMILAR TO THE PREVIOUS ONE
AND NOT FAR FROM THE DYNAMICAL MODEL CONSENSUS.  THIS IS ALSO
BETWEEN THE LATEST GFS DETERMINISTIC RUN AND ITS ENSEMBLE MEAN.
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  24/0300Z 31.0N  26.3W   50 KT  60 MPH
 12H  24/1200Z 31.4N  27.4W   50 KT  60 MPH
 24H  25/0000Z 31.6N  28.7W   50 KT  60 MPH
 36H  25/1200Z 31.6N  30.0W   50 KT  60 MPH
 48H  26/0000Z 31.3N  31.0W   55 KT  65 MPH
 72H  27/0000Z 30.5N  32.5W   60 KT  70 MPH
 96H  28/0000Z 31.0N  34.5W   65 KT  75 MPH
120H  29/0000Z 33.5N  36.5W   65 KT  75 MPH
 
$$
FORECASTER PASCH