ISABEL #53 - DISCUSSION

[AussieMark]

000
WTNT43 KNHC 190843
TCDAT3
TROPICAL STORM ISABEL DISCUSSION NUMBER 53
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
5 AM EDT FRI SEP 19 2003

SURFACE OBSERVATION SUGGEST THE CENTRAL PRESSURE OF ISABEL HAS RISEN
CONSIDERABLY OVER THE PAST FEW HOURS. THE LOWEST PRESSURE OBSERVED
RECENTLY HAS BEEN ABOUT 991 MB IN THE STAUNTON VIRGINIA AREA. THIS
IS THE BASIS FOR THE 987 MB IN THE ADVISORY...AND EVEN THAT MIGHT
BE A STRETCH. SURFACE OBSERVATIONS FROM THE ATLANTIC COAST...
CHESAPEAKE BAY...AND DELAWARE BAY INDICATE SUSTAINED WINDS OF 35-45
KT...SO THE INITIAL INTENSITY IS LOWERED TO 45 KT. ISABEL SHOULD
CONTINUE TO WEAKEN AS IT STARTS TO LOSE TROPICAL CHARACTERISTICS
OVER THE NEXT 12-24 HR.

THE RADAR SIGNATURE HAS WEAKENED TO THE POINT THAT THE CENTER IS
HARD TO PIN DOWN. THE INITIAL MOTION IS THUS A RATHER UNCERTAIN
335/18. ISABEL SHOULD TURN NORTHWARD AND ACCELERATE IN RESPONSE TO
THE APPROACHING TROUGH OVER THE NORTH CENTRAL UNITED STATES...WITH
A GENERAL NORTHWARD MOTION PERSISTING UNTIL DISSIPATION.

FORECASTER BEVEN

FORECAST POSITIONS AND MAX WINDS

INITIAL 19/0900Z 39.2N 78.7W 45 KT...INLAND
12HR VT 19/1800Z 42.8N 79.2W 35 KT...BECOMING EXTRATROPICAL
24HR VT 20/0600Z 49.4N 79.0W 30 KT...EXTRATROPICAL
36HR VT 20/1800Z 56.0N 77.0W 25 KT...EXTRATROPICAL
48HR VT 21/0600Z 61.1N 75.0W 25 KT...EXTRATROPICAL
72HR VT 22/0600Z...ABSORBED BY EXTRATROPICAL LOW