Hurricane ISABEL
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HURRICANE ISABEL DISCUSSION NUMBER 44
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
11 PM EDT TUE SEP 16 2003
RECENT RECON FLIGHT LEVEL WINDS OF 111 AND 109 KNOTS ARE THE BASIS
FOR INCREASING THE WIND SPEED TO 95 KNOTS. THE SHIPS AND GLOBAL
GUIDANCE MODELS SHOW LITTLE CHANGE OR SLIGHT WEAKENING BEFORE
LANDFALL. THERE HAS BEEN SOME DISCUSSION ABOUT THE APPROACH OF THE
NEXT SHORT WAVE TROUGH HAVING A FAVORABLE EFFECT ON INTENSIFICATION
...PERHAPS FROM BAROCLINIC EFFECTS OR FROM AN IMPROVED OUTFLOW
PATTERN. IN ANY CASE THE OFFICIAL FORECAST IS FOR LITTLE CHANGE IN
WIND SPEED BEFORE LANDFALL.
THE INITIAL MOTION IS 335/7. THE FORECAST TRACK AND REASONING IS
CHANGED VERY LITTLE FROM THE PREVIOUS ADVISORY. ISABEL IS ON THE
WEST SIDE OF A DEEP-LAYER RIDGE WHICH IS FORECAST TO BUILD WESTWARD
FOR 48 HOURS UNTIL THE NEXT SHORT WAVE TROUGH APPROACHES. THIS
COULD CAUSE THE TRACK TO BEND SLIGHTLY TO THE LEFT OF THE CURRENT
HEADING...AND THIS IS REFLECTED IN THE OFFICIAL FORECAST.
FORECASTER LAWRENCE
FORECAST POSITIONS AND MAX WINDS
INITIAL 17/0300Z 28.5N 71.7W 95 KT
12HR VT 17/1200Z 29.7N 72.3W 95 KT
24HR VT 18/0000Z 31.7N 73.7W 95 KT
36HR VT 18/1200Z 34.0N 75.5W 95 KT
48HR VT 19/0000Z 36.6N 77.5W 65 KT...INLAND
72HR VT 20/0000Z 43.0N 78.5W 40 KT...INLAND
96HR VT 21/0000Z 54.0N 73.5W 30 KT...INLAND...EXTRATROPICAL
120HR VT 22/0000Z 59.0N 56.0W 30 KT...INLAND...EXTRATROPICAL
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