HOME	ACTIVE CYCLONES	FORECASTS	IMAGERY	ABOUT TPC	RECONNAISSANCE

ZCZC MIATCDAT3 ALL
TTAA00 KNHC DDHHMM
TROPICAL DEPRESSION EIGHT DISCUSSION NUMBER   2
NATIONAL WEATHER SERVICE MIAMI FL
10 PM EST TUE SEP 07 1999
 
SATELLITE IMAGES CONTINUE TO SHOW THAT THE TROPICAL DEPRESSION IS
GRADUALLY BECOMING BETTER ORGANIZED WHILE MOVING TOWARD INCREASINGLY
WARMER WATERS.  THIS SYSTEM HAS A LARGE LOW-LEVEL CYCLONIC ENVELOPE
WITH PLENTY OF BANDING FEATURES AND AN EXCELLENT OUTFLOW. THE LOW-
LEVEL CENTER IS NOT WELL DEFINED YET.  IT IS VERY NEAR TROPICAL
STORM STRENGTH.

BOTH SHIPS AND THE GFDL MODELS BRING THE DEPRESSION TO ABOUT 80 AND
100 KNOTS RESPECTIVELY BY 72 HOURS AND GLOBAL MODELS DEVELOP AN EVEN
LARGER UPPER-LEVEL ANTICYCLONE OVER THE SYSTEM.  STRENGTHENING
IS INDICATED IN THE OFFICIAL INTENSITY FORECAST.  THIS DEPRESSION
HAS ALL THE INGREDIENTS...THAT WE KNOW OF...TO BECOME A MAJOR
HURRICANE EVENTUALLY.  
 
BECAUSE THE DEPRESSION DOES NOT HAVE A WELL DEFINED CENTER YET...THE
INITIAL LOCATION AND MOTION ARE HIGHLY UNCERTAIN AT THIS TIME.  THE
BEST ESTIMATE OF THE INITIAL MOTION IS 285/14...BUT ONCE THE LOW-
LEVEL CENTER BECOMES ESTABLISHED...THE POSITION WILL PROBABLY HAVE
TO BE READJUSTED...MORE LIKELY TO THE RIGHT...IF THE CENTER REFORMS
WITHIN THE DEEP CONVECTION. 

ALL AVAILABLE MODELS...WITH NO EXCEPTION...TURN THE TROPICAL CYCLONE
GRADUALLY TOWARD THE NORTHWEST AND THEN NORTHWARD NORTH...BYPASSING
THE LEEWARD ISLANDS.  THIS IN RESPONSE TO A WEAKENING OF THE
SUBTROPICAL RIDGE WEST OF 70W AND A STRONG APPROACHING MID-LATITUDE
TROUGH.  THIS IS REALISTIC BECAUSE THAT PATTERN HAS BEEN A
PERSISTENT FEATURE THIS SUMMER. BOTH THE OFFICIAL NHC AND HPC
FORECASTS ARE MORE CONSERVATIVE AND ARE ON THE SOUTHERN EDGE OF THE
TRACK ENSEMBLE AND VERY CLOSE TO LBAR...WHICH HAS BEEN PERFORMING
QUITE WELL IN THE DEEP TROPICS.  HOWEVER...IT IS VERY LIKELY THAT
THE FORECAST TRACK WILL HAVE TO BE ADJUSTED TO THE RIGHT LATER
ON...IN AGREEMENT WITH THE GLOBAL MODELS.

AVILA
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL     08/0300Z 15.2N  47.5W    30 KTS
12HR VT     08/1200Z 15.8N  49.5W    40 KTS
24HR VT     09/0000Z 16.5N  52.0W    50 KTS
36HR VT     09/1200Z 17.0N  54.5W    60 KTS
48HR VT     10/0000Z 18.0N  57.0W    70 KTS
72HR VT     11/0000Z 20.0N  61.0W    80 KTS
 
 
NNNN