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TROPICAL STORM FLOYD DISCUSSION NUMBER   3
NATIONAL WEATHER SERVICE MIAMI FL
4 AM EST WED SEP 08 1999

ON INFRARED IMAGES...THE TROPICAL CYCLONE CONTINUES TO BECOME BETTER
ORGANIZED.  BANDING FEATURES...WITH VERY COLD CLOUD TOPS...WRAP
ABOUT HALF WAY AROUND THE SYSTEM CENTER.  THIS GIVES A DATA T-
NUMBER OF 2.5 ON THE DVORAK SCALE.  BOTH TAFB MIAMI AND SAB
WASHINGTON AGREE ON 35 KNOTS FOR THE CURRENT INTENSITY...SO THE
CYCLONE IS BEING NAMED ON THIS ADVISORY.  AS NOTED EARLIER...THERE
IS AN IMPRESSIVE UPPER-TROPOSPHERIC OUTFLOW PATTERN ASSOCIATED WITH
THE STORM AND SEA SURFACE TEMPERATURES WILL CONTINUE TO WARM ALONG
THE PROJECTED TRACK.  THEREFORE STEADY STRENGTHENING IS
FORECAST...SIMILAR TO THE PREVIOUS OFFICIAL INTENSITY FORECAST. 
FLOYD HAS A LARGE CIRCULATION ENVELOPE...TYPICAL FOR CAPE VERDE-
TYPE STORMS DURING THE PEAK OF THE SEASON.  FLOYD IS A GOOD
CANDIDATE TO ULTIMATELY ACHIEVE MAJOR HURRICANE STATUS.

SINCE IT IS A BROAD SYSTEM STILL IN THE DEVELOPING STAGE...THE
CENTER IS NOT YET WELL-DEFINED.  HOWEVER MY BEST ESTIMATE FOR THE
INITIAL MOTION IS 285/14...AS BEFORE.  WATER VAPOR IMAGERY SHOWS A
MID- TO UPPER-TROPOSPHERIC CYCLONE JUST EAST OF BERMUDA AT THIS
TIME.  THIS FEATURE COULD CREATE ENOUGH OF A WEAKNESS IN THE
SUBTROPICAL RIDGE SO THAT FLOYDS COURSE WOULD VEER MORE TO THE
NORTHWEST IN A COUPLE OF DAYS.  IF NOT...THEN THE MAIN FEATURE THAT
WOULD INFLUENCE THE TRACK OF THE STORM WOULD BE A LARGE MID-LATITUDE
TROUGH MOVING TOWARD THE U.S. EAST COAST BY THE END OF THE FORECAST
PERIOD.  THIS WOULD ERODE THE RIDGE OVER THE AREA NORTH OF THE
GREATER ANTILLES...AND CAUSE FLOYD TO TURN MORE NORTHWARD IN ROUGHLY
3 DAYS TIME.  HOWEVER...THERE IS SIGNIFICANT UNCERTAINTY IN 3-DAY
TRACK PREDICTIONS.  THE BAROTROPIC TRACK PREDICTION
MODEL...LBAR...WHICH SHOULD HANDLE SYSTEMS IN THE DEEP TROPICS
FAIRLY WELL...SHOWS A CONTINUED WEST-NORTHWESTWARD TRACK THROUGH THE
FORECAST PERIOD.  THE CURRENT NHC FORECAST TRACK IS ADJUSTED ONLY
SLIGHTLY NORTH OF THE PREVIOUS PACKAGE.  ADDITIONAL NORTHWARD
ADJUSTMENTS TO THE FORECAST TRACK MAY BE REQUIRED WITH TIME.

PASCH
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL     08/0900Z 15.6N  49.1W    35 KTS
12HR VT     08/1800Z 16.2N  51.2W    45 KTS
24HR VT     09/0600Z 17.0N  53.8W    55 KTS
36HR VT     09/1800Z 18.0N  56.0W    65 KTS
48HR VT     10/0600Z 19.0N  58.0W    75 KTS
72HR VT     11/0600Z 21.0N  61.5W    90 KTS
 
 
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