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| #54399 (Received by flhurricane at: 5:05 AM 28.Oct.2005) TCDAT1 TROPICAL STORM BETA DISCUSSION NUMBER 6 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 5 AM EDT FRI OCT 28 2005 THE CONVECTIVE PATTERN HAD BEEN ON THE WANE... BUT DURING THE PAST HOUR OR SO BETA HAS BEEN MAKING A SLIGHT COMEBACK. A STRONG BURST OF DEEP CONVECTION... ALBEIT A SMALL AREA... HAS DEVELOPED NEAR AND TO THE EAST OF THE LOW-LEVEL CENTER WITH CLOUD TOPS OF -80C AND COLDER. EARLIER MICROWAVE IMAGERY BETWEEN 12Z AND 00Z REVEALED A PRONOUNCED BUT SMALL MID-LEVEL EYE FEATURE. HOWEVER... A 28/0110Z SSMIS OVERPASS INDICATED THE EYE FEATURE HAD BEEN DISRUPTED BY SOME EASTERLY MID- TO UPPER-LEVEL SHEAR UNDERCUTTING THE OTHERWISE FAVORABLE OUTFLOW LAYER. SATELLITE INTENSITY ESTIMATES ARE T4.0/65 KT FROM TAFB... T3.5/55 KT FROM SAB... AND T3.0/45 KT FROM AFWA. A 27/2300Z QUIKSCAT HI-RES OVERPASS ALSO SHOWED NO WIND VECTORS... FLAGGED AND UNFLAGGED... HIGHER THAN 40 KT. HOWEVER... THE VERY SMALL INNER CORE NOTED IN EARLIER MICROWAVE DATA WOULD LIKELY BE UNDERSAMPLED BY QUIKSCAT. GIVEN THE DISRUPTION OF THE EYE FEATURE ...THE INITIAL INTENSITY REMAINS AT 55 KT... WHICH MAY BE GENEROUS. THE INITIAL MOTION HAS BEEN A STEADY 360/03 FOR THE PAST 14 HOURS... AND THAT IS THE MOTION USED FOR THIS ADVISORY. THE FORECAST TRACK IS LESS THAN STRAIGHTFORWARD. FIRST... A VIGOROUS TROPICAL WAVE LOCATED ABOUT 350 NMI NORTHEAST OF BETA HAS DEVELOPED SOME IMPRESSIVE AROUND THE MID-LEVEL CIRCULATION... WHICH WILL LIKELY STRENGTHEN THAT SYSTEM AND RESULT IN SOME POSSIBLE BINARY INTERACTION IN THE SHORT TERM THAT THE 28/00Z NAM ALLUDED TO. SECOND... THERE IS A DISTINCT BIFURCATION IN THE MODEL SUITE. THE GFS...GFDL...NOGAPS...GFS ENSEMBLE... AND ECMWF MODELS ARE TIGHTLY CLUSTERED ON A WEST OR WEST-SOUTHWEST TRACK IMMEDIATELY FROM THE CURRENT POSITION. IN CONTRAST... THE UKMET...CANADIAN... CLIPER...LBAR...AND NHC98 MODELS ARE TIGHTLY CLUSTERED ABOUT A NORTHWESTWARD MOTION ACROSS EXTREME NORTHEASTERN CENTRAL AMERICA AND TOWARD THE YUCATAN CHANNEL. THE FIRST GROUP APPEARS TO HAVE TO MUCH RIDGE TO THE NORTH INITIALIZED... POSSIBLY DUE TO THE 00Z HEIGHTS AT SAN ANDRES BEING TOO HIGH. THE 500 MB HEIGHTS INCREASED 20 METERS BETWEEN 27/12Z AND 28/00Z...EVEN THOUGH BETA MOVED 30 NMI CLOSER. THE OFFICIAL FORECAST TRACK IS BETWEEN THE TWO EXTREMES... EXCEPT CLOSER TO THE PREVIOUS TRACK AND THE GUNA AND GUNS MODELS. SSTS ARE VERY WARM AT 29C AND HIGHER... AND THE UPPER-LEVEL FLOW PATTERN IS QUITE FAVORABLE FOR AT LEAST STEADY STRENGTHENING. THE ONLY SLIGHT INHIBITING FACTOR IS THE VERTICAL SHEAR... WHICH IS FORECAST TO IN CREWASE TO 15 KT BY 24 HOURS... BEFORE DECREASING TO LESS THAN 10 KT BY 36-48 HOURS. THE OFFICIAL INTENSITY FORECAST IS SIMILAR TO THE PREVIOUS FORECAST... AND REMAINS ABOVE THE SHIPS MODEL. WIND RADII WERE DECREASED BASED ON THE QUIKSCAT WINDS AND A NORTHWEST 30-KT WIND REPORT AT 06Z FROM SHIP ZCAM4 LOCATED ABOUT 48 NMI SOUTHWEST OF THE CENTER. FORECASTER STEWART FORECAST POSITIONS AND MAX WINDS INITIAL 28/0900Z 12.3N 81.2W 55 KT 12HR VT 28/1800Z 12.8N 81.4W 65 KT 24HR VT 29/0600Z 13.4N 81.8W 75 KT 36HR VT 29/1800Z 13.8N 82.4W 85 KT 48HR VT 30/0600Z 14.1N 83.1W 90 KT 72HR VT 31/0600Z 14.5N 84.9W 35 KT...DISSIPATING INLAND 96HR VT 01/0600Z 14.7N 86.5W 25 KT...DISSIPATING INLAND 120HR VT 02/0600Z 15.0N 88.0W 20 KT...REMNANT LOW INLAND |
