[Tropical] Tropical Cyclone Discussion

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WTNT44 KNHC 090308
TCDAT4
HURRICANE DENNIS DISCUSSION NUMBER  18
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
11 PM EDT FRI JUL 08 2005

DENNIS CONTINUES MOVING ACROSS WESTERN CUBA AND IS APPROACHING THE
STRAITS OF FLORIDA.  SATELLITE IMAGERY AND RADAR DATA FROM THE KEY
WEST WSR-88D SHOW SOME DEGRADATION OF THE EYE STRUCTURE OVER THE
PAST FEW HOURS...ALTHOUGH DOPPLER WINDS CONTINUE TO INDICATE A
TIGHT INNER CORE.  BASED ON EXTRAPOLATION OF THE DOPPLER WINDS...
THE INITIAL INTENSITY IS REDUCED TO 95 KT...ALTHOUGH THERE IS A
LARGE MARGIN FOR ERROR ON BOTH THE WINDS AND THE ESTIMATED CENTRAL
PRESSURE.

THE INITIAL MOTION IS A SOMEWHAT UNSTEADY 310/12.  THERE IS LITTLE
CHANGE IN THE SYNOPTIC STEERING PATTERN OR THE FORECAST PHILOSOPHY.
DENNIS IS ON THE SOUTHEAST SIDE OF A MID/UPPER-LEVEL RIDGE THAT
EXTENDS FROM THE WESTERN ATLANTIC ACROSS FLORIDA INTO THE GULF OF
MEXICO...WHILE AN MID/UPPER-LEVEL TROUGH EXTENDS FROM THE
MID-MISSISSIPPI VALLEY SOUTHWESTWARD TO THE TEXAS COAST.  LARGE-
SCALE MODELS FORECAST THE ATLANTIC RIDGE TO BUILD NORTHWESTWARD...
WHICH SHOULD KEEP DENNIS ON A NORTHWESTWARD OR NORTH-NORTHWESTWARD
TRACK UNTIL IT REACHES THE NORTHERN GULF COAST.  TRACK MODEL
GUIDANCE IS CLUSTERED BETWEEN LANDFALL IN SOUTHEASTERN LOUISIANA
AND THE WESTERN FLORIDA PANHANDLE.  THE GFDL AND GFS HAVE SHIFTED
TO THE RIGHT OF THEIR PREVIOUS FORECASTS...WHILE THE UKMET REMAINS
TO THE LEFT OF CENTER OF THE GUIDANCE ENVELOPE.  CONSENSUS MODELS
REMAIN CLUSTERED AROUND A LANDFALL BETWEEN PASCAGOULA AND FT.
WALTON BEACH.  THE FORECAST TRACK IS SHIFTED A LITTLE TO THE LEFT
OF THE PREVIOUS TRACK...TO MATCH THE INITIAL POSITION AND MOTION IN
THE FIRST 24 HR AND TO BE A LITTLE CLOSER TO THE CONSENSUS MODELS
FROM 24-48 HR.

DENNIS SHOULD BE OVER WATER SHORTLY...AND UPPER-LEVEL WINDS AND SEA
SURFACE TEMPERATURES APPEAR FAVORABLE FOR RE-INTENSIFICATION.  ALL
INTENSITY GUIDANCE INDICATES THE SYSTEM SHOULD REGAIN MAJOR
HURRICANE STATUS...AND THAT IS FOLLOWED IN THE INTENSITY FORECAST
WHICH BRINGS DENNIS BACK TO 110 KT IN 24 HR AND MAINTAINS THAT
INTENSITY UNTIL LANDFALL.  THERE IS A POSSIBILITY THAT DENNIS COULD
STRENGTHEN MORE THAN CURRENTLY FORECAST.  AFTER LANDFALL...DENNIS
SHOULD WEAKEN AND EVENTUALLY BECOME A LOW PRESSURE AREA OVER THE
MID-MISSISSIPPI AND OHIO VALLEYS.

34 KT WIND RADII IN THE EASTERN SEMICIRCLE WERE INCREASED ON THE
BASIS OF SURFACE OBSERVATIONS.

THERE IS AN AIR FORCE RESERVE HURRICANE HUNTER AIRCRAFT FLYING ALONG
THE NORTH COAST OF CUBA WAITING FOR DENNIS TO EMERGE.  HOWEVER...
THE AIRCRAFT IS EXPERIENCING MAJOR COMMUNICATION PROBLEMS AND ONLY
LIMITED DATA CAN BE TRANSMITTED AT THIS MOMENT.  A VORTEX MESSAGE
MAY BE AVAILABLE ONCE DENNIS MOVES BACK OVER THE WATER.

FORECASTER BEVEN


FORECAST POSITIONS AND MAX WINDS

INITIAL      09/0300Z 23.0N  82.1W    95 KT...INLAND
 12HR VT     09/1200Z 24.4N  83.4W   100 KT...OVER WATER
 24HR VT     10/0000Z 26.3N  84.9W   110 KT
 36HR VT     10/1200Z 28.5N  86.2W   110 KT
 48HR VT     11/0000Z 30.9N  87.5W   100 KT...INLAND
 72HR VT     12/0000Z 35.5N  90.0W    30 KT...INLAND
 96HR VT     13/0000Z 38.0N  89.0W    25 KT...INLAND DISSIPATING
120HR VT     14/0000Z 39.0N  85.5W    20 KT...INLAND REMNANT LOW


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