[Tropical] Tropical Cyclone Discussion

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WTNT44 KNHC 062059
TCDAT4
TROPICAL STORM DENNIS DISCUSSION NUMBER   8
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
5 PM EDT WED JUL 06 2005

WHILE 18Z DVORAK CLASSIFICATIONS WERE T4.0/65 KT FROM TAFB AND
SAB...AND THE UNITED STATES AIR FORCE RECONNAISSANCE AIRCRAFT
RECENTLY MEASURED A CENTRAL PRESSURE OF 987 MB...MAXIMUM 700 MB
FLIGHT LEVEL WINDS HAVE THUS FAR BEEN ONLY 58 KT.  THE ADVISORY
INTENSITY IS THEREFORE ADJUSTED TO 55 KT...BUT THE RECENT PRESSURE
FALLS AND THE INCREASINGLY ORGANIZED APPEARANCE ON SATELLITE
IMAGERY SUGGEST THAT DENNIS COULD REACH HURRICANE INTENSITY
SHORTLY.  CONDITIONS ARE EXPECTED TO REMAIN FAVORABLE FOR
INTENSIFICATION TO...AND THEN SUSTAINING...MAJOR HURRICANE STATUS.
IN FACT...THE LATEST GFDL MODEL OUTPUT FORECASTS 127 KT AND 931 MB
BY 48 HOURS...WHILE THE SHIPS GUIDANCE SHOWS ABOUT 100 KT IN 72
HOURS.  THE OFFICIAL FORECAST MORE CLOSELY FOLLOWS THE SHIPS
GUIDANCE AND IS SIMILAR TO THE PREVIOUS ADVISORY...MAKING DENNIS A
MAJOR HURRICANE IN 48 HOURS.

DENNIS IS CLOSELY FOLLOWING THE PREVIOUS FORECAST TRACK...WITH AN
ESTIMATED INITIAL MOTION OF 295/12.  WHILE THE OVERALL TRACK
FORECAST REASONING HAS NOT CHANGED...SEVERAL OF THE DYNAMICAL
MODELS HAVE SHIFTED SOMEWHAT TO THE LEFT...OR WEST...AT DAYS THREE
THROUGH FIVE...TAKING DENNIS THROUGH THE CENTRAL RATHER THAN THE
EASTERN GULF OF MEXICO.  THE LATER PORTION OF THE OFFICIAL FORECAST
IS ONLY ADJUSTED SLIGHTLY TO THE LEFT...SINCE IT IS PRUDENT NOT TO
MAKE LARGE CHANGES TO THE TRACK FROM ONE FORECAST PACKAGE TO THE
NEXT.  SOME OF THE MODEL GUIDANCE MAY VERY WELL SHIFT BACK TO THE
EAST LATER...AND FURTHER OFFICIAL FORECAST ADJUSTMENTS WILL WAIT TO
SEE HOW THE MODEL TRENDS EVOLVE.

FORECASTER KNABB/PASCH


FORECAST POSITIONS AND MAX WINDS

INITIAL      06/2100Z 16.0N  72.5W    55 KT
 12HR VT     07/0600Z 17.0N  74.3W    70 KT
 24HR VT     07/1800Z 18.4N  76.7W    80 KT
 36HR VT     08/0600Z 20.0N  79.1W    95 KT
 48HR VT     08/1800Z 21.4N  81.4W   100 KT
 72HR VT     09/1800Z 24.0N  84.5W   100 KT
 96HR VT     10/1800Z 27.5N  86.5W   100 KT
120HR VT     11/1800Z 31.0N  88.0W    65 KT...INLAND


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