500 
 WTNT43 KNHC 032059
 TCDAT3
 TROPICAL STORM HANNA DISCUSSION NUMBER  28
 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   AL082008
 500 PM EDT WED SEP 03 2008
  
 AN ASCAT PASS FROM 14Z REVEALED THAT THE LOW-LEVEL CIRCULATION OF
 HANNA WAS BECOMING ELONGATED IN RESPONSE TO THE ASYMMETRIC
 DISTRIBUTION OF CONVECTION.  IN SPITE OF THIS...DATA FROM THE
 RECONNAISSANCE AIRCRAFT INDICATE THAT HANNA IS BECOMING A LITTLE
 BETTER ORGANIZED.  TROPICAL STORM FORCE WINDS HAVE RETURNED TO THE
 SOUTHWEST QUADRANT AND THE PRESSURE HAS FALLEN TO 989 MB.  THE
 AIRCRAFT DATA CONTINUE TO SUGGEST THAT THE MAXIMUM WINDS ARE ABOUT
 50 KT.
 
 A MORE DEFINITIVE NORTHWARD MOTION HAS COMMENCED...WITH THE INITIAL
 ESTIMATE BEING 360/10.   THE UPPER LOW OFF OF NEW ENGLAND IS
 BEGINNING TO MOVE OUT...AND AS IT DOES SO MID-LEVEL RIDGING WILL
 BUILD IN BEHIND IT.  HANNA SEEMS TO BE FOLLOWING THE CONVECTION
 FAIRLY WELL...AND I'VE HAD TO SPEED UP MY PREVIOUS FORECAST A
 LITTLE BIT.  THE OFFICIAL FORECAST IS IN BEST AGREEMENT WITH A
 BLEND OF THE ECMWF AND THE GFS.  THE HWRF AND GFDL CONTINUE TO BE
 FASTER THAN THE OFFICIAL FORECAST...AND IF HANNA DEVELOPS FASTER
 THAN SHOWN BELOW ADDITIONAL TIMING ADJUSTMENTS MAY NEED TO BE MADE.
 IT'S WORTH NOTING THAT CONNECTING THE 48 AND 72 HOUR FORECAST POINTS
 WITH A STRAIGHT LINE GIVES A MISLEADING UNDERESTIMATE OF THE
 THREAT TO THE GEORGIA AND SOUTH CAROLINA COASTS.  ONLY A GRADUAL
 RIGHT TURN IS EXPECTED AFTER 48 HOURS.
 
 AS THE UPPER LOW IN THE BAHAMAS AND HANNA SEPARATE...THE SOUTHERLY
 SHEAR OVER THE CYCLONE WILL TURN SOUTHEASTERLY AND LESSEN.  THIS IS
 EXPECTED TO PROVIDE A MORE FAVORABLE ENVIRONMENT FOR
 STRENGTHENING...ALTHOUGH NONE OF THE OBJECTIVE AIDS SHOWS VERY
 MUCH.  THE SHIPS AND LGEM BRING THE SYSTEM ONLY TO 60 KT...AND THE
 HWRF NOT QUITE THAT HIGH.  THE OFFICIAL FORECAST IS IN GOOD
 AGREEMENT WITH THE GFDL WHICH BRINGS HANNA TO 70 KT PRIOR TO
 LANDFALL.
   
  
 FORECAST POSITIONS AND MAX WINDS
  
 INITIAL      03/2100Z 21.9N  71.9W    50 KT
  12HR VT     04/0600Z 23.2N  72.7W    55 KT
  24HR VT     04/1800Z 25.2N  74.5W    60 KT
  36HR VT     05/0600Z 27.4N  76.6W    65 KT
  48HR VT     05/1800Z 30.0N  78.5W    70 KT
  72HR VT     06/1800Z 36.8N  76.9W    50 KT...INLAND
  96HR VT     07/1800Z 44.5N  67.0W    35 KT...EXTRATROPICAL
 120HR VT     08/1800Z 48.0N  55.0W    35 KT...EXTRATROPICAL
  
 $$
 FORECASTER FRANKLIN