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Tropical Depression EIGHT (Text)

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TROPICAL DEPRESSION EIGHT DISCUSSION NUMBER   2
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   AL082007
500 PM EDT WED SEP 12 2007
 
THE CLOUD PATTERN OF THE DEPRESSION HAS CHANGED VERY LITTLE SINCE
THIS MORNING WITH THE CIRCULATION CENTER ESTIMATED NEAR THE EASTERN
PORTION OF THE DEEP CONVECTION.  DVORAK INTENSITY ESTIMATES
FROM TAFB AND SAB SUPPORT 35 KT.  SINCE THERE IS SOME UNCERTAINTY
IN THE EXACT CENTER LOCATION...THE INITIAL INTENSITY WILL REMAIN 30
KT. THE DEPRESSION IS CURRENTLY PASSING ABOUT 60 NM SOUTH OF NOAA
BUOY 41041...WHICH HAS REPORTED A PEAK 1-MINUTE WIND OF 28 KT AND A
MINIMUM PRESSURE OF 1008.6 MB.
 
THE INITIAL MOTION ESTIMATE IS 290/10. THE TRACK GUIDANCE IS IN GOOD
AGREEMENT ON A WEST-NORTHWESTWARD MOTION DURING THE NEXT COUPLE OF
DAYS.  THE RIDGE IS EXPECTED TO WEAKEN AS A MID-TO UPPER-LEVEL LOW
DEVELOPS SEVERAL HUNDRED MILES NORTHEAST OF THE LEEWARD ISLANDS. 
THIS IS EXPECTED TO CAUSE THE DEPRESSION TO DECELERATE DURING THE
NEXT COUPLE OF DAYS.  THE NEW TRACK FORECAST REMAINS CLOSE TO THE
PREVIOUS ADVISORY THROUGH 48 HOURS BUT IS ADJUSTED A LITTLE
NORTHWARD THEREAFTER...IN CLOSE AGREEMENT WITH THE CONSENSUS OF
HWRF...GFDL...UMKET...AND GFS MODELS.
 
MOST OF THE INTENSITY GUIDANCE INDICATES THAT THE EASTERLY SHEAR
CURRENTLY AFFECTING THE CYCLONE SHOULD WEAKEN DURING THE NEXT 24
HOURS AND THE GUIDANCE SUGGESTS THAT DEPRESSION SHOULD GRADUALLY
STRENGTHEN.  THE GFDL...HWRF AND SHIPS MODELS BRING THE DEPRESSION
TO HURRICANE STRENGTH IN ABOUT 72 HOURS. THE OFFICIAL FORECAST WILL
REMAIN SLIGHTLY BELOW THIS GUIDANCE AND KEEP THE DEPRESSION
JUST BELOW HURRICANE STRENGTH.  AT DAYS 4 AND 5...STRONG
SOUTHWESTERLY UPPER-LEVEL WINDS SOUTH OF THE MID-TO UPPER-LEVEL LOW
ARE EXPECTED TO PRODUCE INCREASING SHEAR.  THE GFDL RESPONDS TO THIS
BY WEAKENING THE CYCLONE AND THE OFFICIAL FORECAST WILL REFLECT SOME
WEAKENING LATE IN THE PERIOD.
  
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      12/2100Z 13.5N  45.5W    30 KT
 12HR VT     13/0600Z 13.9N  46.7W    35 KT
 24HR VT     13/1800Z 14.3N  47.9W    45 KT
 36HR VT     14/0600Z 14.7N  48.8W    50 KT
 48HR VT     14/1800Z 15.1N  49.8W    55 KT
 72HR VT     15/1800Z 16.2N  52.2W    60 KT
 96HR VT     16/1800Z 17.5N  55.5W    60 KT
120HR VT     17/1800Z 18.5N  58.5W    55 KT
 
$$
FORECASTER BROWN
 
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