[Tropical] Tropical Cyclone Discussion

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WTNT44 KNHC 092058
TCDAT4
HURRICANE DENNIS DISCUSSION NUMBER  21
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
5 PM EDT SAT JUL 09 2005

WHAT A DIFFERENCE 6 HOURS MAKES! SATELLITE...RADAR...AND NOAA AND
AIR FORCE RECONNAISSANCE DATA INDICATE DENNIS HAS POSSIBLY STARTED
A RAPID DEEPENING PHASE. THE EYE HAS BECOME BECOME DEFINED IN BOTH
RADAR AND SATELLITE IMAGERY...AND THE PRESSURE IS NOW 955 MB...DOWN
ALMOST 10 MB IN THE PAST 6 HOURS. THE WINDS ARE GRADUALLY BEGINNING
TO CATCH UP WITH THE PRESSURE FALLS AS INDICATED BY A 700 MB
FLIGHT-LEVEL WIND OF 101 KT...EQUAL TO ABOUT A 91 KT SURFACE WIND
...IN THE NORTHEAST QUADRANT.

THE INITIAL MOTION ESTIMATE IS 325/12. DENNIS HAS MADE A LARGE
WOBBLE TO THE WEST-NORTHWEST IN THE PAST 2 HOURS...BUT THIS IS
PROBABLY A TEMPORARY MOTION DUE TO THE DEEP CONVECTION HAVING
EXPLODED AND WRAPPED AROUND THE WEST SIDE OF THE EYE. ONCE THE
CONVECTIVE PATTERN BECOMES MORE SYMMETRICAL...I EXPECT DENNIS TO
RESUME A NORTHWEST MOTION OF 320 TO 325 DEGREES. THE NEW 18Z NHC
MODEL GUIDANCE IS MORE CONVERGENT AND IS NOW IN BETTER AGREEMENT ON
A TRACK TOWARD THE WESTERN FLORIDA PANHANDLE TO SOUTHERN ALABAMA
AREA. THE NOGAPS AND GFDN MODELS HAVE SHIFTED SHARPLY TO THE RIGHT
...OR EAST OF LOUISIANA...AND THE NHC MODEL CONSENSUS HAS ALSO
SHIFTED TO THE RIGHT AND CLOSER TO THE PREVIOUS 3 NHC FORECAST
TRACKS. AS A RESULT...NO SIGNIFICANT CHANGE WAS MADE TO THE
PREVIOUS FORECAST TRACK.

THE CENTRAL PRESSURE OF 955 MB NORMALLY WOULD SUPPORT AN INITIAL
INTENSITY OF 105-110 KT...BUT THE INNER CORE PRESSURE GRADIENT IS
STILL FLAT DUE TO LAND INTERACTION WITH CUBA LAST NIGHT. HOWEVER...
THE SMALL 10-15 NMI DIAMETER EYE...RECENT SHARP PRESSURE FALLS...
WARM WATER AHEAD OF THE CYCLONE...AND IMPRESSIVE OUTFLOW ALL
SUGGEST THAT DENNIS SHOULD GO ON AND INTENSIFY INTO A MAJOR
HURRICANE...AND POSSIBLY EVEN REGAIN CATEGORY 4 STRENGTH BEFORE IT
MAKES LANDFALL ON SUNDAY.

VARIOUS WIND RADII WERE INCREASED BASED ON RECON DATA

FORECASTER STEWART


FORECAST POSITIONS AND MAX WINDS

INITIAL      09/2100Z 25.7N  84.6W    90 KT
 12HR VT     10/0600Z 27.5N  85.8W   100 KT
 24HR VT     10/1800Z 29.9N  87.2W   110 KT
 36HR VT     11/0600Z 32.3N  88.4W    65 KT...INLAND
 48HR VT     11/1800Z 34.2N  89.3W    30 KT...DISSIPATING INLAND
 72HR VT     12/1800Z 37.0N  89.0W    20 KT...REMNANT LOW INLAND
 96HR VT     13/1800Z 38.0N  87.0W    20 KT...REMNANT LOW INLAND
120HR VT     14/1800Z 39.0N  82.0W    20 KT...REMNANT LOW INLAND


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