000
WTNT44 KNHC 030838
TCDAT4
 
TROPICAL STORM NADINE DISCUSSION NUMBER  83
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL142012
500 AM AST WED OCT 03 2012

NADINE IS SHOWING A SHEARED CLOUD PATTERN THIS MORNING...WITH THE
LOW-LEVEL CENTER PARTLY EXPOSED AT THE NORTHWESTERN EDGE OF THE
CENTRAL CONVECTION DUE TO 20-30 KT OF NORTHERLY VERTICAL WIND SHEAR. 
THE INITIAL INTENSITY REMAINS 45 KT BASED ON A BLEND OF SATELLITE
T-NUMBERS AND CI-NUMBERS FROM TAFB AND SAB.

NADINE IS GRADUALLY TURNING TO THE LEFT...WITH THE INITIAL MOTION
NOW 075/9.  SATELLITE IMAGERY SHOWS A LARGE DEEP-LAYER LOW AND
ASSOCIATED SURFACE COLD FRONT APPROACHING NADINE FROM THE
NORTHWEST.  THIS SYSTEM SHOULD CAUSE THE MUCH SMALLER NADINE TO
ACCELERATE NORTHEASTWARD AND THEN NORTH-NORTHEASTWARD OVER THE
NEXT 48 HR...AND DURING THIS TIME THE FORECAST TRACK IS NEAR THE
CENTER OF THE TRACK GUIDANCE ENVELOPE.  THE GUIDANCE BECOMES
DIVERGENT BETWEEN 48-72 HR...WITH THE GFS-BASED GUIDANCE NOW
FORECASTING A NORTHEASTWARD MOTION...WHILE THE ECMWF AND UKMET CALL
FOR NADINE TO TURN WESTWARD ON THE NORTH SIDE OF THE LOW.  THIS
PART OF THE TRACK FORECAST FOLLOWS THE ECMWF AND UKMET IN AGREEMENT
WITH THE PREVIOUS FORECAST AND GUIDANCE FROM THE OCEAN PREDICTION
CENTER.

NADINE SHOULD ENCOUNTER INCREASING SHEAR AND DECREASING SEA SURFACE
TEMPERATURES DURING THE NEXT 24-36 HR.  THE INTENSITY FORECAST
CALLS FOR LITTLE CHANGE IN STRENGTH BEFORE THE STORM REACHES THE
AZORES...BUT IT WOULD NOT BE SURPRISING IF SOME WEAKENING OCCURRED. 
THE CYCLONE SHOULD MERGE WITH THE APPROACHING FRONT AND BECOME
EXTRATROPICAL IN ABOUT 48 HR...WITH THE SYSTEM BECOMING ABSORBED
WITHIN THE LARGE DEEP-LAYER LOW AFTER 72 HR.
 
THE FORECAST WIND RADII HAVE BEEN REVISED BASED ON INPUT FROM THE
OCEAN PREDICTION CENTER. 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  03/0900Z 34.9N  34.6W   45 KT  50 MPH
 12H  03/1800Z 35.8N  32.6W   45 KT  50 MPH
 24H  04/0600Z 38.7N  29.6W   45 KT  50 MPH
 36H  04/1800Z 42.7N  27.2W   45 KT  50 MPH
 48H  05/0600Z 46.8N  25.9W   40 KT  45 MPH...POST-TROP/EXTRATROP
 72H  06/0600Z 48.0N  29.5W   40 KT  45 MPH...POST-TROP/EXTRATROP
 96H  07/0600Z...ABSORBED BY EXTRATROPICAL LOW
 
$$
FORECASTER BEVEN