ZCZC MIATCDAT4 ALL TTAA00 KNHC DDHHMM TROPICAL DEPRESSION FOUR SPECIAL DISCUSSION NUMBER 1 NATIONAL WEATHER SERVICE MIAMI FL 1030 AM EST MON AUG 24 1998 THE SYSTEM IN THE CENTRAL TROPICAL ATLANTIC HAS BECOME WELL-ENOUGH ORGANIZED TO BEGIN ISSUING ADVISORIES ON IT AS TROPICAL DEPRESSION FOUR. THE CLOUD PATTERN IS FAIRLY SMALL BUT SATELLITE PICTURES SHOW A RATHER TIGHTLY WOUND BANDING STRUCTURE. DVORAK T-NUMBERS FROM SAB AND TAFB ARE 2.0 AND 2.5...RESPECTIVELY...PUTTING THE SYSTEM AT THE THRESHOLD OF STORM STRENGTH. THE INITIAL MOTION IS 285/17 KT. THE 06Z AVN KEEPS A MID-LEVEL ANTICYCLONE TO THE NORTH OF THE TD THROUGH THE PERIOD...AND IN FACT STRENGTHENS THE HIGH DUE NORTH OF THE SYSTEM AT 48 HOURS. THIS SHOULD CONTINUE TO STEER THE TROPICAL CYCLONE TOWARD THE WNW...AS INDICATED BY ALL AVAILABLE GUIDANCE. STRENGTHENING IS FORECAST AT A RATE BETWEEN SHIFOR...WHICH SHOWS SLIGHT INTENSIFICATION...AND THE SHIPS SCHEME WHICH IMPLIES HURRICANE INTENSITY BY THE END OF THE PERIOD. WHILE THE OUTFLOW LOOKS FAIRLY SYMMETRICAL AT THIS TIME...THE OUTPUT FROM THE BAM INDICATE WESTERLY SHEAR AT VERY HIGH LEVELS IN THE FUTURE. RAPPAPORT FORECAST POSITIONS AND MAX WINDS INITIAL 24/1530Z 14.1N 37.0W 30 KTS 12HR VT 25/0000Z 14.7N 39.4W 35 KTS 24HR VT 25/1200Z 15.6N 42.9W 45 KTS 36HR VT 26/0000Z 16.5N 46.2W 50 KTS 48HR VT 26/1200Z 17.4N 49.4W 55 KTS 72HR VT 27/1200Z 19.5N 56.0W 60 KTS NNNN