ZCZC MIATCDAT4 ALL TTAA00 KNHC DDHHMM TROPICAL STORM NICOLE DISCUSSION NUMBER 18 NATIONAL WEATHER SERVICE MIAMI FL 4 AM EST SUN NOV 29 1998 DESPITE THE SHEARING ENVIRONMENT...THE CENTER OF THE STORM IS NOT EXPOSED...AND IS LOCATED UNDER THE WESTERN EDGE OF A PERSISTENT MASS OF DEEP CONVECTION. UPPER-LEVEL DIFFLUENCE OVER THE AREA APPEARS TO BE A CONTRIBUTING FACTOR FOR MAINTAINING NICOLE/S INTENSITY AT THIS TIME. HOWEVER...GRADUAL WEAKENING SHOULD SOON TAKE PLACE SINCE THE SHEAR IS FORECAST TO PERSIST AND THE STORM IS MOVING OVER SLOWLY COOLING SST/S. NICOLE IS LIKELY TO LOSE ITS TROPICAL CHARACTERISTICS IN A DAY OR TWO. MOTION IS GRADUALLY BENDING TO THE RIGHT DUE TO SOUTHWESTERLY STEERING AHEAD OF A BROAD MID-TROPOSPHERIC TROUGH...AND A GRADUAL TURN TO THE RIGHT SHOULD CONTINUE. TRACK GUIDANCE MODELS CONTINUE TO SHOW A LARGE SPREAD. THE U.K. MET OFFICE MODEL AND DEEP-LAYER STEERING SHOW CONSIDERABLE ACCELERATION TO THE NORTHEAST. HOWEVER THE BAROTROPIC MODEL...THE GFDL...NOGAPS AND MEDIUM-DEPTH STEERING ARE MUCH SLOWER AND WELL TO THE RIGHT OF THE ABOVE TRACKS. THE OFFICIAL FORECAST...LIKE THE PREVIOUS ONE...IS A COMPROMISE AND ROUGHLY THE AVERAGE OF THE ABOVEMENTIONED OBJECTIVE TRACK PREDICTIONS. A SHIP...CALL SIGN PDFB...REPORTED ONLY 17 KNOT WINDS ABOUT 75 N MI WEST OF THE CENTER AT 06Z. BASED ON THIS OBSERVATION...THE RADII OF TROPICAL STORM FORCE WINDS ARE DECREASED OVER THE WESTERN SEMICIRCLE. PASCH FORECAST POSITIONS AND MAX WINDS INITIAL 29/0900Z 30.4N 45.8W 45 KTS 12HR VT 29/1800Z 31.3N 44.8W 40 KTS 24HR VT 30/0600Z 32.3N 43.3W 35 KTS 36HR VT 30/1800Z 33.0N 42.0W 35 KTS...EXTRATROPICAL 48HR VT 01/0600Z 33.5N 40.5W 35 KTS...EXTRATROPICAL 72HR VT 02/0600Z 34.5N 37.0W 35 KTS...EXTRATROPICAL NNNN