Tropical Storm ALBERTO

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TROPICAL STORM ALBERTO DISCUSSION NUMBER   8
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   AL012006
1100 PM EDT SUN JUN 11 2006
 
DATA FROM SATELLITES AND AN AIR FORCE RESERVE RECONNAISSANCE
AIRCRAFT THIS EVENING INDICATE ALBERTO HAS CHANGED LITTLE IN
OVERALL STRUCTURE. SEVERAL SMALL-SCALE CIRCULATIONS HAVE BEEN NOTED
IN SATELLITE IMAGERY ROTATING CYCLONICALLY AROUND A MEAN CENTER...
AND THE ADVISORY POSITION IS THE MIDPOINT BETWEEN THOSE SWIRLS. THE
ADVISORY POSITION IS TO THE WEST OF THE LAST RECON POSITION AT
12/0143Z... AND IS CLOSE TO THE CENTROID OF THE LARGE SURFACE
PRESSURE ENVELOPE. THE 40-KT INTENSITY IS BASED ON THE ASSUMPTION
THAT THE RECON AIRCRAFT MAY NOT HAVE SAMPLED STRONGER WINDS TO THE
EAST OF THE FLIGHT TRACK WITHIN SOME OF THE STRONGER CONVECTION.
 
UPPER-AIR DATA THIS EVENING INDICATE THE MID- TO UPPER-LEVEL RIDGE
PREVIOUSLY LOCATED ACROSS CENTRAL FLORIDA HAS ERODED AND LIFTED
NORTHWARD TO NORTHERN FLORIDA...WHILE THE LOW-LEVEL RIDGE HAS ALSO
SHIFTED NORTHWARD BUT HAS REMAINED INTACT ALL THE WAY WESTWARD
TO EASTERN TEXAS. THIS...COUPLED WITH THE SOUTHWESTERLY UPPER-LEVEL
FLOW...HAS MAINTAINED A MODERATE TO STRONG SHEAR PATTERN ACROSS THE
CYCLONE...WHICH IS EXPECTED TO CONTINUE FOR THE NEXT 12-18 HOURS.
AFTER THAT...MOST OF THE MODELS AGREE THAT THE DEEP LAYER FLOW WILL
BECOME VERTICALLY ALIGNED FROM THE SOUTHWEST...AND THAT SHOULD ACT
TO TURN ALBERTO NORTHEASTWARD TOWARD NORTHERN FLORIDA. THE GFDL ONCE
AGAIN APPEARS TO BE OVERCOMPENSATING FOR THE VERTICAL SHEAR AS IT
TAKES THE CYCLONE MORE NORTHWARD INTO GEORGIA... AS DOES THE FSU
SUPERENSEMBLE BY 36H. THE OFFICIAL FORECAST TRACK IS SIMILAR TO THE
PREVIOUS TRACK AND FOLLOWS THE GENERAL MID-LEVEL WEST-SOUTHWESTERLY
STEERING FLOW PATTERN AFTER 24 HOURS...WHICH KEEPS ALBERTO SOUTH OF
THE SUBTROPICAL JETSTREAM AND IN THE DIVERGENT RIGHT-REAR QUADRANT.

ONCE ALBERTO TURNS TOWARD THE NORTHEAST...THE VERTICAL SHEAR IS
EXPECTED TO ABATE SOMEWHAT. THIS MAY ALLOW FOR SOME SLIGHT
STRENGTHENING IN THE 24-36H TIME FRAME...AS SUGGESTED BY THE SHIPS
INTENSITY MODEL... BUT NOT AS ROBUST AS THE GFDL MODEL.
 
FORECASTER STEWART
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      12/0300Z 25.3N  87.7W    40 KT
 12HR VT     12/1200Z 26.6N  87.2W    45 KT
 24HR VT     13/0000Z 27.9N  85.9W    50 KT
 36HR VT     13/1200Z 28.7N  84.2W    50 KT
 48HR VT     14/0000Z 30.1N  81.7W    40 KT...INLAND
 72HR VT     15/0000Z 34.0N  75.0W    40 KT...EXTRATROPICAL
 96HR VT     16/0000Z 40.0N  63.5W    40 KT...EXTRATROPICAL
120HR VT     17/0000Z 46.0N  52.0W    40 KT...EXTRATROPICAL
 
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