Hurricane ISABEL
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HURRICANE ISABEL DISCUSSION NUMBER 36
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
11 PM EDT SUN SEP 14 2003
RECONNAISSANCE AIRCRAFT DATA CONFIRMED 135-KNOT SURFACE WINDS AT 18Z
AND THERE WILL BE ANOTHER MISSION AT 06Z...SO THE INITIAL OFFICIAL
INTENSITY IS LEFT AT 135 KNOTS. SATELLITE IMAGES SHOW THAT CLOUD
TOPS HAVE WARMED TODAY BUT A LARGE WELL-DEFINED IMPRESSIVE EYE
PERSISTS AS WELL AS IMPRESSIVE CLOUD SYMMETRY.
THE INITIAL MOTION IS 290/11...IT HAS REMAINED THE SAME FOR OVER 24
HOURS. THE TRACK GUIDANCE ALSO REMAINS ABOUT THE SAME WITH THE
GLOBAL MODELS CLOSELY CLUSTERED AND SHOWING A LANDFALL IN JUST
UNDER 96 HOURS ALONG THE MID ATLANTIC COAST. THE SCENARIO CONSISTS
OF A DEEP-LAYER MEAN HIGH SOUTH OF NOVA SCOTIA AND TWO SHORT WAVES
MOVING ACROSS THE EASTERN UNITED STATES IN THE NEXT 5 DAYS. THE
FIRST TROUGH WILL SLOW ISABELS FORWARD SPEED WHILE IT TURNS
NORTH-NORTHWESTWARD AROUND THE PERIPHERY OF THE HIGH. THE SECOND
TROUGH WILL CAUSE AN ACCELERATION TOWARD THE NORTH-NORTHWEST WITH
ISABEL MOVING OVER THE GREAT LAKES AND BECOMING EXTRATROPICAL BY
DAY 5.
ONLY SLOW WEAKENING IS FORECAST FOR THE NEXT 4 DAYS...SO ISABEL IS
LIKELY TO STILL BE QUITE DANGEROUS AT LANDFALL. SINCE THE TRACK IS
FORECAST TO APPROACH THE COAST AT A SMALL ANGLE...A SMALL CHANGE IN
DIRECTION COULD RESULT IN A LANDFALL WELL TO THE NORTH OF THE MID
ATLANTIC COAST. ALSO OFFICIAL 4-DAY TRACK FORECAST ERRORS AVERAGE
ABOUT 275 MILES. WE INTEND THAT THE ISABEL FORECASTS WILL BE MORE
ACCURATE...BUT INTERESTS FROM THE CAROLINAS THROUGH THE NORTHEASTERN
STATES SHOULD CLOSELY MONITOR THE PROGRESS OF ISABEL.
FORECASTER LAWRENCE
FORECAST POSITIONS AND MAX WINDS
INITIAL 15/0300Z 24.5N 68.3W 135 KT
12HR VT 15/1200Z 25.2N 69.5W 135 KT
24HR VT 16/0000Z 26.2N 70.6W 130 KT
36HR VT 16/1200Z 27.6N 71.4W 125 KT
48HR VT 17/0000Z 28.9N 72.1W 120 KT
72HR VT 18/0000Z 32.8N 74.2W 115 KT
96HR VT 19/0000Z 38.3N 76.8W 90 KT...INLAND
120HR VT 20/0000Z 45.5N 80.0W 35 KT...INLAND...EXTRATROPICAL
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