000
WTNT42 KNHC 080254
TCDAT2
 
HURRICANE KATIA DISCUSSION NUMBER  40
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL122011
1100 PM AST WED SEP 07 2011
 
CONVENTIONAL SATELLITE AND MICROWAVE IMAGES INDICATE THAT KATIA IS
AN ASYMMETRIC HURRICANE.  DEEP CONVECTION IS LIMITED TO THE EASTERN
HALF OF THE CIRCULATION...WITH THE LOW-LEVEL CENTER ESTIMATED TO BE
ON THE WESTERN EDGE OF THE INNER-MOST CONVECTIVE BAND.  THIS
PATTERN IS THE RESULT OF MODERATE WESTERLY SHEAR AND DRY AIR
ENTRAINING INTO THE CIRCULATION.  NOAA BUOY 41048...LOCATED ABOUT
90 N MI NORTH OF THE CENTER OF KATIA...RECENTLY REPORTED A MAXIMUM
1-MINUTE WIND OF 58 KT WITH A GUST TO 72 KT.  ALTHOUGH THE LATEST
DVORAK CLASSIFICATIONS SUGGEST THAT KATIA MAY HAVE WEAKENED A
LITTLE...I PREFER TO KEEP THE INITIAL INTENSITY AT 70 KT GIVEN THE
BUOY OBSERVATION.  LITTLE CHANGE IN STRENGTH IS FORECAST DURING THE
NEXT SEVERAL DAYS...AND ALL OF THE GLOBAL MODELS SHOW KATIA
BECOMING A LARGE EXTRATROPICAL STORM OVER THE NORTH ATLANTIC.
 
KATIA IS NOW BEGINNING THE ANTICIPATED NORTHWARD TURN AS IT MOVES
BETWEEN THE SUBTROPICAL RIDGE AND A LARGE MID- TO UPPER-LEVEL LOW
OVER THE OHIO VALLEY OF THE UNITED STATES.  A PRONOUNCED INCREASE
IN FORWARD SPEED AND A TURN TO THE NORTHEAST AND EAST-NORTHEAST IS
FORECAST TO OCCUR ON FRIDAY AS THE CYCLONE BECOMES EMBEDDED IN THE
MID-LATITUDE FLOW.  THE MODELS REMAIN IN VERY GOOD AGREEMENT...AND
THE OFFICIAL FORECAST IS AN UPDATE OF THE PREVIOUS ONE.  THE
EXTRATROPICAL FORECAST POINTS ARE VERY CLOSE TO THE GUIDANCE
PROVIDED BY THE OCEAN PREDICTION CENTER.

FORECAST POSITIONS AND MAX WINDS
 
INIT  08/0300Z 30.8N  70.0W   70 KT  80 MPH
 12H  08/1200Z 32.5N  70.2W   70 KT  80 MPH
 24H  09/0000Z 35.2N  69.5W   70 KT  80 MPH
 36H  09/1200Z 37.9N  67.0W   70 KT  80 MPH
 48H  10/0000Z 40.4N  61.0W   70 KT  80 MPH
 72H  11/0000Z 46.6N  40.6W   65 KT  75 MPH...POST-TROP/EXTRATROP
 96H  12/0000Z 55.0N  22.0W   65 KT  75 MPH...POST-TROP/EXTRATROP
120H  13/0000Z 60.0N   6.0W   55 KT  65 MPH...POST-TROP/EXTRATROP
 
$$
FORECASTER CANGIALOSI/BEVEN