000
WTNT44 KNHC 301443
TCDAT4
 
HURRICANE NADINE DISCUSSION NUMBER  72
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL142012
1100 AM AST SUN SEP 30 2012
 
THE EYE OF NADINE HAS BECOME A LITTLE SMALLER AND BETTER DEFINED
THIS MORNING...HOWEVER THE CONVECTIVE CLOUD TOPS HAVE WARMED
SOMEWHAT.  THIS RESULTS IN LITTLE CHANGE TO THE MOST RECENT
SUBJECTIVE AND OBJECTIVE DVORAK T-NUMBERS...AND A CONSENSUS OF
THE LATEST SATELLITE-BASED INTENSITY ESTIMATES SUPPORT AN INITIAL
INTENSITY OF 80 KT.  THE HURRICANE IS EXPECTED TO REMAIN IN A
LOW-SHEAR ENVIRONMENT DURING THE NEXT COUPLE OF DAYS.  SINCE NADINE
IS FORECAST TO SLOW DOWN AND NOT MOVE VERY FAR...THERE COULD BE
SOME UPWELLING WHICH WILL CAUSE THE ALREADY MARGINAL SSTS TO COOL.
AT THE SAME TIME...THE UPPER ATMOSPHERE IS FORECAST TO COOL WHICH
COULD OFFSET THE COOLER WATER.  THEREFORE...LITTLE CHANGE IN
INTENSITY IS PREDICTED DURING THE NEXT COUPLE OF DAYS.  AFTER 48
HOURS...INCREASING WESTERLY SHEAR AND PROGRESSIVELY COOLER WATER
ALONG THE PATH OF THE STORM SHOULD CAUSE WEAKENING...AND NADINE
IS PREDICTED TO BECOME POST-TROPICAL BY THE END OF THE PERIOD.
 
NADINE HAS BEEN MOVING STEADILY NORTHWESTWARD DURING THE PAST 12-18
HOURS...HOWEVER THE HURRICANE SHOULD SLOW DOWN CONSIDERABLY LATER
TODAY AS THE STEERING CURRENTS WEAKEN ONCE AGAIN.  NADINE IS
FORECAST TO COMPLETE A COUNTERCLOCKWISE LOOP DURING THE NEXT COUPLE
OF DAYS AS IT REMAINS BETWEEN MID-LEVEL RIDGES TO ITS EAST AND
WEST AND A BROAD TROUGH OVER THE NORTH-CENTRAL ATLANTIC. AFTER 48
HOURS...A LARGE DEEP-LAYER TROUGH IS FORECAST TO MOVE OFF THE
COAST OF CANADA.  THIS TROUGH IS EXPECTED TO DEEPEN AND CUT OFF
AS IT MOVES INTO THE CENTRAL ATLANTIC IN 4-5 DAYS.  THIS SYSTEM
SHOULD FINALLY CAUSE NADINE TO ACCELERATE NORTHEASTWARD...HOWEVER
THERE IS SOME DISAGREEMENT IN THE MODELS NEAR THE END OF THE PERIOD
AS TO WHETHER NADINE CONTINUES NORTHEASTWARD OVER THE NORTHEAST
ATLANTIC OR TURNS WESTWARD AND IS ABSORBED BY THE UPPER-LOW.  THE
NHC FORECAST SPLITS THESE DIFFERENCES AND IS NEAR THE DYNAMICAL
MODEL CONSENSUS AND THE GFS ENSEMBLE MEAN. 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  30/1500Z 37.1N  38.6W   80 KT  90 MPH
 12H  01/0000Z 37.3N  39.1W   80 KT  90 MPH
 24H  01/1200Z 36.6N  39.3W   75 KT  85 MPH
 36H  02/0000Z 35.9N  39.0W   70 KT  80 MPH
 48H  02/1200Z 35.6N  38.1W   65 KT  75 MPH
 72H  03/1200Z 36.3N  35.1W   60 KT  70 MPH
 96H  04/1200Z 40.8N  30.0W   55 KT  65 MPH
120H  05/1200Z 48.0N  28.0W   45 KT  50 MPH...POST-TROP/EXTRATROP
 
$$
FORECASTER BROWN