000
WTNT42 KNHC 110856
TCDAT2
 
TROPICAL STORM LESLIE DISCUSSION NUMBER  48
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL122012
500 AM AST TUE SEP 11 2012
 
LESLIE IS RAPIDLY TRANSFORMING INTO AN EXTRATROPICAL CYCLONE AS 
THE COLDEST CLOUD TOPS ARE NOW LOCATED TO THE NORTH AND NORTHWEST
OF THE CENTER...AND COLD AIR IS BEGINNING TO WRAP AROUND THE
SOUTHWESTERN SIDE OF THE SYSTEM.  DATA FROM CANADIAN BUOY 44139
HAVE BEEN VERY HELPFUL IN LOCATING THE CENTER AND DETERMING THAT
THE MINIMUM PRESSURE IS SIGNIFICANTLY LOWER THAN PREVIOUSLY
ESTIMATED.  THE BUOY REPORTED SUSTAINED WINDS OF 47 KT WITH A GUST
TO 60 KT AROUND 0600 UTC...AND A MINIMUM PRESSURE OF 971.5 MB ABOUT
AN HOUR LATER.  THE BUOY REPORTS INDICATE THAT LESLIE IS ALSO
LOCATED SLIGHTLY WEST OF THE EARLIER POSITION ESTIMATES.  THE
INITIAL INTENSITY REMAINS 60 KT AND IS BASED ON ASCAT DATA
THAT SHOWED A LARGE AREA OF 50 TO 55 KT WINDS. 

LESLIE IS MOVING NORTH-NORTHEAST AT 35 KT...AND WILL CONTINUE TO
ACCELERATE TODAY.  THE CENTER WILL BE PASSING OVER EASTERN
NEWFOUNDLAND VERY SOON AND WINDS ARE ALREADY INCREASING ALONG THE
COAST.  THE NHC TRACK FORECAST HAS BEEN SHIFTED WEST OF THE PREVIOUS
ADVISORY DURING THE FIRST 12 TO 24 HOURS TO ACCOUNT FOR THE MORE
WESTWARD INITIAL POSTION.  

LESLIE SHOULD COMPLETE ITS TRANSITION TO AN EXTRATROPICAL CYCLONE
THIS MORNING AND IS FORECAST TO REMAIN A LARGE AND POWERFUL
CYCLONE OVER THE NORTH ATLANTIC FOR THE NEXT TWO TO THREE DAYS. 
THE EXTRATROPICAL LOW SHOULD TURN EAST-NORTHEASTWARD...THEN EASTWARD
DURING THE NEXT COUPLE OF DAYS.  THE GLOBAL MODELS SHOW THE
EXTRATROPICAL CYCLONE BEING ABSORBED BY ANOTHER LOW OVER THE
NORTHEASTERN ATLANTIC IN JUST OVER 72 HOURS.

THE INITIAL WIND RADII HAVE BEEN ADJUSTED OUTWARD BASED ON RECENT
ASCAT AND SURFACE DATA. 

FORECAST POSITIONS AND MAX WINDS
 
INIT  11/0900Z 45.7N  56.4W   60 KT  70 MPH
 12H  11/1800Z 51.0N  52.0W   60 KT  70 MPH...POST-TROP/EXTRATROP
 24H  12/0600Z 57.5N  43.5W   60 KT  70 MPH...POST-TROP/EXTRATROP
 36H  12/1800Z 61.5N  33.0W   60 KT  70 MPH...POST-TROP/EXTRATROP
 48H  13/0600Z 63.5N  25.0W   55 KT  65 MPH...POST-TROP/EXTRATROP
 72H  14/0600Z 61.5N   9.0W   45 KT  50 MPH...POST-TROP/EXTRATROP
 96H  15/0600Z...ABSORBED
 
$$
FORECASTER BROWN