ZCZC MIATCDAT3 ALL
TTAA00 KNHC DDHHMM
HURRICANE KAREN DISCUSSION NUMBER 7
NATIONAL WEATHER SERVICE MIAMI FL
5 AM EDT SUN OCT 14 2001
LATEST INFRARED SATELLITE IMAGES INDICATE THAT A SOLID RING OF
CONVECTION HAS DEVELOPED AROUND THE EYE AND TOPS HAVE COOLED. AS
SUCH...THE INITIAL INTENSITY IS INCREASED TO 70 KT AND THIS IS
SUPPORTED BY SATELLITE INTENSITY ESTIMATES OF 65 TO 70 KT FROM BOTH
TAFB AND SAB.
THE INITIAL MOTION ESTIMATE IS 010/08. KAREN HAS BEEN MOVING
SLIGHTLY EAST OF DUE NORTH THE PAST 6 TO 9 HOURS. THE DEEP LONGWAVE
TROUGH OVER THE CENTRAL U.S. CONTINUES TO DIG SOUTHEASTWARD...WHICH
IS HELPING TO AMPLIFY THE DOWNSTREAM RIDGE ALONG THE U.S. EAST
COAST. THE SUBSEQUENT RIDGING HAS CAUSED A SHORTWAVE TROUGH JUST
WEST OF KAREN TO DIG SOUTHWARD AND BECOME MORE NEGATIVELY TILTED.
THIS IS CAUSING THE MID-LEVEL FLOW TO BACK AND BECOME MORE SOUTHERLY
WHICH SHOULD HELP TO STEER THE CYCLONE ON A MORE NORTHWARD TRACK IN
THE SHORT TERM. BY 24 HOURS...ALL OF THE GLOBAL MODELS ARE
FORECASTING THE LONGWAVE TROUGH TO MOVE TO THE U.S. EAST COAST AND
ALSO BECOME NEGATIVELY TILTED. THIS SHOULD HELP KAREN TO ACCELERATE
NORTHWARD TOWARD NOVA SCOTIA AND THEN EVENTUALLY TURN TOWARD THE
NORTHEAST AND CROSS THE EASTERN PORTION OF NOVA SCOTIA AND WESTERN
NEWFOUNDLAND AS THE TROUGH BEGINS TO LIFT OUT TO THE NORTHEAST. THE
OFFICIAL FORECAST IS CLOSE TO THE AVN-NOGAPS MODEL CONSENSUS AND IS
A LITTLE TO THE LEFT OF THE PREVIOUS FORECAST TRACK.
KAREN HAS LIKELY PEAKED IN INTENSITY AND GRADUAL WEAKENING SHOULD
BEGIN WITHIN THE NEXT 12 TO 18 HOURS AS THE CYCLONE BEGINS TO TRACK
OVER MUCH COOLER WATER THAT LIES JUST NORTH OF 39N LATITUDE. KAREN
IS EXPECTED TO BEGIN TO INTERACT WITH AN EXTRATROPICAL LOW PRESSURE
SYSTEM OVER NORTHEAST CANADA IN 36 HOURS AND BECOME COMPLETELY
ABSORBED BY THE LOW IN ABOUT 72 TO 96 HOURS...IF NOT SOONER.
FORECASTER STEWART
FORECAST POSITIONS AND MAX WINDS
INITIAL 14/0900Z 39.1N 63.6W 70 KTS
12HR VT 14/1800Z 40.4N 63.3W 65 KTS
24HR VT 15/0600Z 42.6N 63.2W 60 KTS...BECOMING EXTRATROPICAL
36HR VT 15/1800Z 45.3N 62.7W 50 KTS...INLAND EXTRATROPICAL
48HR VT 16/0600Z 48.0N 59.0W 40 KTS...INLAND EXTRATROPICAL
72HR VT 17/0600Z 51.5N 54.0W 30 KTS...EXTRATROPICAL
NNNN
Problems?