Tropical Storm BETA

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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
 
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