Tropical Storm DOLLY

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TROPICAL STORM DOLLY DISCUSSION NUMBER   7
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   AL042008
1100 PM EDT MON JUL 21 2008
 
DOLLY HAS CONTINUED TO GENERATE DEEP CONVECTION NEAR THE CORE THIS
EVENING...AND NOW SHOWS EVIDENCE OF WRAPPING A BAND IN THE SOUTHERN
SEMICIRCLE AGAINST THE EASTERLY SHEAR...WHICH HAS BEEN DECREASING. 
DATA FROM THE NOAA AIRCRAFT...HOWEVER...INDICATE THAT THE SURFACE
CENTER IS SOUTH OF THE APPARENT INFRARED CENTER.   DOLLY IS ALSO
MOVING OVER A WARM GULF EDDY.  GIVEN THESE CHANGES...STRENGTHENING
SHOULD BEGIN VERY SOON.  THE UPPER-LEVEL FLOW IS NOT YET IDEAL FOR
DEVELOPMENT...WITH THE ANTICYCLONE LOCATED TO THE EAST OF
DOLLY...BUT THE GLOBAL MODELS FORECAST THESE FEATURES TO BECOME
BETTER CONNECTED JUST BEFORE LANDFALL.  ON THE OTHER HAND...DOLLY
IS EXPECTED TO ENCOUNTER A COLD EDDY IN ABOUT 18-24 HOURS...WHEN
THE FORWARD SPEED IS EXPECTED TO BE QUITE A BIT SLOWER THAN IT IS
NOW...AND THIS ENCOUNTER COULD PROVIDE A DAMPER ON THE
INTENSIFICATION RATE IN THE LAST HOURS PRIOR TO LANDFALL.  THE
BOTTOM LINE OF ALL THIS IS THAT DOLLY VERY LIKELY WILL BECOME A
HURRICANE...BUT THE ODDS ARE AGAINST IT BECOMING A MAJOR HURRICANE.

THE INITIAL MOTION IS 280/15.  THE GUIDANCE MODELS FROM YESTERDAY
DID A NICE JOB IN FORECASTING THE INCREASE IN SPEED TODAY...AND ARE
IN EXCELLENT AGREEMENT THAT THE FORWARD MOTION WILL SLOW
SIGNIFICANTLY TOMORROW AS THE UPPER LOW TO THE SOUTH OF DOLLY
WEAKENS ALONG WITH THE UPPER-LEVEL EASTERLIES.  THE MID-LEVEL RIDGE
OVER EAST TEXAS IS FORECAST TO ERODE SLIGHTLY AS A PAIR OF
MID-LATITUDE SHORT WAVES MOVE THROUGH THE GREAT LAKES.  THIS IS
EXPECTED TO CAUSE A BEND OF THE TRACK TO THE RIGHT OVER THE NEXT
24-36 HOURS.  MODEL GUIDANCE IS FAIRLY TIGHTLY CLUSTERED AND THE
OFFICIAL FORECAST IS IN THE MIDDLE OF THE GUIDANCE ENVELOPE...WITH
THE GFS TO THE SOUTH AND THE GFDL TO THE NORTH.


FORECAST POSITIONS AND MAX WINDS
 
INITIAL      22/0300Z 23.1N  92.8W    45 KT
 12HR VT     22/1200Z 23.9N  94.4W    55 KT
 24HR VT     23/0000Z 24.8N  95.8W    65 KT
 36HR VT     23/1200Z 25.6N  96.9W    75 KT
 48HR VT     24/0000Z 26.2N  98.0W    50 KT...INLAND
 72HR VT     25/0000Z 26.5N 101.5W    25 KT...REMNANT LOW
 96HR VT     26/0000Z...DISSIPATED
 
$$
FORECASTER FRANKLIN
 
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