[Tropical] Tropical Cyclone Discussion

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WTNT43 KNHC 040254
TCDAT3

TROPICAL STORM LEE DISCUSSION NUMBER  10
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL132011
1000 PM CDT SAT SEP 03 2011

NATIONAL WEATHER SERVICE RADAR DATA AND SURFACE OBSERVATIONS
INDICATE THAT THE CENTER OF LEE HAS BEEN MEANDERING NEAR THE
SOUTHERN COAST OF LOUISIANA THIS EVENING.  AN OIL PLATFORM LOCATED
ABOUT 20 MILES WEST OF MARSH ISLAND HAS BEEN REPORTING A PRESSURE
OF AROUND 988 MB MOST OF THE EVENING.  THE WINDS AT THAT SITE WERE
VARIABLE FOR SEVERAL HOURS...BUT RECENTLY HAVE SHIFTED TO THE
SOUTHEAST AROUND 15-20 KT INDICATING THAT THE CENTER OF LEE REMAINS
OFFSHORE.  THE HIGHEST SUSTAINED WIND OBSERVATIONS DURING THE PAST
FEW HOURS ARE 40-44 KT AT SEVERAL ELEVATED RIGS OFF THE COAST OF
SOUTHWEST LOUISIANA.  BASED ON THESE OBSERVATIONS...THE INITIAL
INTENSITY IS SET AT 45 KT...WHICH COULD BE A LITTLE GENEROUS.  LEE
IS EXPECTED TO WEAKEN AS IT MOVES INLAND DURING THE NEXT DAY OR SO.
HOWEVER...SINCE A LARGE PORTION OF THE CIRCULATION WILL REMAIN OVER
WATER...LEE WILL LIKELY REMAIN A TROPICAL STORM FOR ANOTHER 24 TO
36 HOURS.

LEE IS FORECAST TO DRIFT NORTHWARD DURING THE NEXT DAY OR SO AS A
SHORTWAVE TROUGH MOVES INTO THE NORTH-CENTRAL UNITED STATES.  AFTER
THAT TIME...THE CYCLONE IS EXPECTED TO INTERACT WITH A COLD FRONT
THAT SHOULD TURN LEE EASTWARD...THEN NORTHEASTWARD WITHIN 24 TO 36
HOURS.  BOTH THE GFS AND ECMWF MODELS SUGGEST LEE WILL BECOME AN
EXTRATROPICAL CYCLONE IN 2-3 DAYS...A SOMEWHAT UNUSUAL OCCURRENCE
IN THIS AREA AT THIS TIME OF YEAR.  THE GLOBAL MODELS AND THE
OFFICIAL FORECAST ALSO NOW INDICATE DISSIPATION OVER THE SOUTHERN
APPALACHIANS IN 4-5 DAYS.  THE OFFICIAL FORECAST HAS BEEN SHIFTED
WESTWARD THROUGH 24 HOURS DUE TO THE MORE WESTWARD INITIAL
POSITION...BUT THE REMAINDER OF THE TRACK IS ESSENTIALLY AN UPDATE
OF THE PREVIOUS FORECAST.

SINCE HEAVY RAINS AND STRONG WINDS EXTEND VERY FAR FROM THE
CENTER IT IS IMPORTANT NOT TO FOCUS ON THE EXACT FORECAST TRACK.


FORECAST POSITIONS AND MAX WINDS

INIT  04/0300Z 29.4N  92.6W   45 KT  50 MPH
 12H  04/1200Z 30.0N  92.5W   40 KT  45 MPH...INLAND
 24H  05/0000Z 30.4N  91.9W   40 KT  45 MPH...INLAND
 36H  05/1200Z 30.7N  90.9W   35 KT  40 MPH...INLAND
 48H  06/0000Z 32.0N  89.1W   30 KT  35 MPH...INLAND
 72H  07/0000Z 34.0N  86.5W   20 KT  25 MPH...POST-TROP/EXTRATROP
 96H  08/0000Z 36.5N  84.0W   20 KT  25 MPH...POST-TROP/EXTRATROP
120H  09/0000Z...DISSIPATED

$$
FORECASTER BROWN


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