HOME	ACTIVE CYCLONES	FORECASTS	IMAGERY	ABOUT TPC	RECONNAISSANCE

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TROPICAL STORM DENNIS DISCUSSION NUMBER  48
NATIONAL WEATHER SERVICE MIAMI FL
5 PM EDT SAT SEP 04 1999
 
AIRCRAFT AND RADAR DATA INDICATE THAT DENNIS IS VERY CLOSE TO
HURRICANE STRENGTH AS IT MAKES LANDFALL. A GPS DROPSONDE INDICATED
63 KT SURFACE WINDS NORTH OF THE CENTER...AND THE LATEST CENTRAL
PRESSURE FROM THE RECONNAISSANCE AIRCRAFT IS 984 MB. THE LATEST
RADAR SUGGESTS THE WINDS ARE STARTING TO DIMINISH AS THE EYEWALL
MOVES ONSHORE...SO DENNIS WILL BE KEPT AS A 60 KT TROPICAL STORM ON
THIS PACKAGE. ALTHOUGH FURTHER STRENGTHENING IS UNLIKELY...ANY
STRENGTHENING WOULD MAKE DENNIS A HURRICANE. THUS...HURRICANE
WARNINGS ARE CONTINUED AT LEAST UNTIL THE CORE PASSES BEYOND THE
PAMLICO SOUND. THE CYCLONE HAS A LARGE CIRCULATION...SO WEAKENING
AFTER LANDFALL MAY BE SLOWER THAN NORMAL. DENNIS IS LIKELY TO BECOME
EXTRATROPICAL BY THE END OF THE FORECAST PERIOD.

THERE IS LITTLE CHANGE IN THE FORECAST TRACK OR THE FORECAST TRACK
PHILOSOPHY FROM THE PREVIOUS PACKAGE. DENNIS SHOULD CONTINUE
NORTHWEST INTO NORTHERN NORTH CAROLINA...FOLLOWED BY A GRADUAL
RECURVATURE THROUGH THE MID ATLANTIC STATES IN ADVANCE OF THE LARGE
MID/UPPER LEVEL TROUGH ADVANCING EASTWARD FROM THE GREAT PLAINS. ONE
INTERESTING NOTE IS THAT DESPITE A SLIGHTLY FASTER INITIAL MOTION...
AVIATION MODEL-BASED GUIDANCE MOVES DENNIS SLOWER AFTER RECURVATURE
THAN 6 HOURS AGO. THE 72 HOUR POSITION IS A COMPROMISE BETWEEN THIS
GUIDANCE AND THE MUCH FASTER NOGAPS AND UKMET.
 
BEVEN
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL     04/2100Z 34.9N  76.3W    60 KTS
12HR VT     05/0600Z 35.9N  77.2W    50 KTS...INLAND
24HR VT     05/1800Z 37.7N  77.8W    40 KTS...INLAND
36HR VT     06/0600Z 39.5N  77.8W    35 KTS...INLAND
48HR VT     06/1800Z 42.0N  77.0W    30 KTS...INLAND
72HR VT     07/1800Z 47.0N  72.0W    25 KTS...EXTRATROPICAL
 
 
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