000
WTNT44 KNHC 250858
TCDAT4
 
TROPICAL STORM NADINE DISCUSSION NUMBER  51
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL142012
500 AM AST TUE SEP 25 2012
 
NADINE HAS RECENTLY DEVELOPED AN EYE-LIKE FEATURE IN THE MID-LEVEL
CLOUD FIELD...AND BANDING FEATURES HAVE INCREASED BECOME A LITTLE
BETTER ORGANIZED. UW-CIMSS ADT AND NHC AODT SATELLITE ESTIMATES ARE
T2.6/37 KT AND T2.5/35 KT...AND A 25/0054 UTC OSCAT OVERPASS THAT
ARRIVED AFTER THE PREVIOUS ADVISORY WAS ISSUED SUPPORTS MAINTAINING
THE INITIAL INTENSITY AT 40 KT. UPPER-LEVEL OUTFLOW IS RESTRICTED
TO THE NORTHERN SEMICIRCLE.

THE INITIAL MOTION IS NOW 260/5. OVERALL...THERE IS NO SIGNIFICANT
CHANGE TO THE PREVIOUS FORECAST TRACK OR REASONING. A STRONG
DEEP-LAYER RIDGE TO THE WEST-NORTHWEST OF NADINE IS EXPECTED TO
AMPLIFY AS IT SHIFTS SLOWLY EASTWARD OVER THE NEXT FEW DAYS. THE
INCREASE IN NORTHERLY FLOW ON THE EAST SIDE OF THE RIDGE IS
EXPECTED TO DRIVE NADINE SOUTHWESTWARD TO SOUTHWARD DURING THE
NEXT 48 HOURS...FOLLOWED BY A TURN TOWARD THE WEST AND NORTHWEST IN
THE LATER FORECAST PERIODS AS THE RIDGE SHIFTS TO THE NORTHEAST OF
THE TROPICAL CYCLONE. REGARDLESS OF THE EXACT MOTION...THE FORWARD
SPEED OF NADINE IS EXPECTED TO REMAIN RATHER SLOW AT AROUND 5 KT. 
THE OFFICIAL TRACK FORECAST IS A LITTLE SOUTH OF THE PREVIOUS
ADVISORY AND LIES CLOSE TO THE DYNAMICAL MODEL CONSENSUS. IT SHOULD
BE NOTED THAT THE TRACK MODELS REMAIN QUITE DIVERGENT AT DAYS
4-5...SO THE FORECAST LATE IN THE PERIOD IS OF LOW CONFIDENCE.

VERTICAL SHEAR IS FORECAST TO WEAKEN TO LESS THAN 10 KT OVER THE
NEXT 24-36 HOURS. THE LOW SHEAR CONDITIONS...IN CONJUNCTION WITH
NADINE MOVING OVER WARMER WATERS AS IT TRACKS SOUTHWARD...SHOULD
ALLOW FOR SOME GRADUAL STRENGTHENING TO OCCUR OVER THE NEXT FEW
DAYS. AFTER 96 HOURS OR SO...SOME WEAKENING IS LIKELY LATER AS
SOUTHWESTERLY SHEAR INCREASES AHEAD OF A DEEP-LAYER TROUGH FORECAST
TO MOVE EASTWARD FROM THE UNITED STATES.  THE NHC INTENSITY
FORECAST IS IDENTICAL TO THE PREVIOUS ONE...AND FOLLOWS THE
STATISTICAL-DYNAMICAL SHIPS AND LGEM GUIDANCE.
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  25/0900Z 32.1N  29.6W   40 KT  45 MPH
 12H  25/1800Z 31.8N  30.3W   40 KT  45 MPH
 24H  26/0600Z 31.1N  30.7W   45 KT  50 MPH
 36H  26/1800Z 30.0N  30.9W   45 KT  50 MPH
 48H  27/0600Z 29.0N  31.5W   50 KT  60 MPH
 72H  28/0600Z 29.0N  33.0W   60 KT  70 MPH
 96H  29/0600Z 30.0N  34.0W   60 KT  70 MPH
120H  30/0600Z 32.0N  35.0W   50 KT  60 MPH
 
$$
FORECASTER STEWART