Hurricane NADINE

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HURRICANE NADINE DISCUSSION NUMBER  64
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL142012
1100 AM AST FRI SEP 28 2012

MICROWAVE SATELLITE IMAGERY INDICATES THAT NADINE HAS DEVELOPED AN
EYE DURING THE PAST SEVERAL HOURS...WITH THIS FEATURE ALSO
APPEARING IN CONVENTIONAL IMAGERY.  SATELLITE INTENSITY ESTIMATES
FROM TAFB AND SAB HAVE INCREASED TO 65 KT...WHILE RECENT AMSU-BASED
INTENSITY ESTIMATES FROM CIMSS AND CIRA HAVE BEEN IN THE 60-75 KT
RANGE.  BASED ON THESE DATA...NADINE HAS REGAINED HURRICANE STATUS
AND THE INITIAL INTENSITY IS INCREASED TO 65 KT.
 
THE INITIAL MOTION IS NOW 310/7.  FOR THE NEXT 48 HR OR SO NADINE
SHOULD MOVE GENERALLY NORTH-NORTHWESTWARD BETWEEN A DEEP-LAYER
RIDGE OVER THE EASTERN ATLANTIC AND A MID/UPPER-LEVEL LOW CURRENTLY
LOCATED NEAR 32N48W.  THE GLOBAL MODELS FORECAST NADINE TO MERGE OR
MOVE UNDER THIS LOW IN ABOUT 72 HR...WITH THE SYSTEM MOVING SLOWLY
IN AN AREA OF LIGHT STEERING CURRENTS JUST SOUTH OF THE MAIN BRANCH
OF THE WESTERLIES.  THE TRACK GUIDANCE IS IN GOOD AGREEMENT THROUGH
48 HR...BUT DIVERGES THERAFTER.  THE NOGAPS AND THE CANADIAN MODELS
SHOW A SOUTHWESTWARD MOTION BY 120 HR.  THE REST OF THE DYNAMICAL
MODELS SHOW SOME TYPE OF EASTWARD MOTION BY THAT TIME...WITH THE
ECMWF AND UKMET NOW SUPPORTING THIS SCENARIO.  THE NEW FORECAST
TRACK IS SIMILAR TO THE PREVIOUS TRACK...SHOWING A NORTH-
NORTHWESTWARD MOTION THROUGH 48 HR...FOLLOWED BY A SLOW NORTHWARD
AND EASTWARD DRIFT.  THE NEW TRACK LIES CLOSE TO THE VARIOUS
CONSENSUS MODELS.

THERE REMAINS UNCERTAINTY AS TO HOW MUCH SHEAR NADINE WILL ENCOUNTER
DURING THE NEXT 24-36 HR...AS SEVERAL OF THE GLOBAL MODELS FORECAST
AN UPPER-LEVEL SHORTWAVE TROUGH NEAR THE HURRICANE THAT COULD
SHIELD IT FROM THE WORST OF THE FORECAST SOUTHWESTERLY SHEAR.  THE
SHIPS...LGEM...AND INTENSITY CONSENSUS MODELS SHOW MODEST
STRENGTHENING DURING THIS TIME...AND THE INTENSITY FORECAST FOLLOWS
THIS SCENARIO.  THE CYCLONE SHOULD ENCOUNTER COOLER SEA SURFACE
TEMPERATURES IN 24 HR OR SO...WHICH SHOULD STOP INTENSIFICATION. 
BY THE END OF THE FORECAST PERIOD...INCREASING NORTHERLY SHEAR AND
EVEN COLDER SEA SURFACE TEMPERATURES SHOULD LEAD TO A STEADY
WEAKENING.

THE INITIAL AND FORECAST WIND RADII HAVE BEEN REVISED BASED ON A
RECENT ASCAT OVERPASS.

 
FORECAST POSITIONS AND MAX WINDS
 
INIT  28/1500Z 29.6N  34.7W   65 KT  75 MPH
 12H  29/0000Z 30.5N  35.3W   70 KT  80 MPH
 24H  29/1200Z 32.3N  36.1W   70 KT  80 MPH
 36H  30/0000Z 34.2N  36.6W   70 KT  80 MPH
 48H  30/1200Z 35.7N  37.2W   65 KT  75 MPH
 72H  01/1200Z 36.5N  37.5W   60 KT  70 MPH
 96H  02/1200Z 36.5N  37.0W   55 KT  65 MPH
120H  03/1200Z 36.5N  36.0W   45 KT  50 MPH
 
$$
FORECASTER BEVEN
 
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