Hurricane HANNA

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HURRICANE HANNA DISCUSSION NUMBER  20
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   AL082008
500 PM EDT MON SEP 01 2008
 
THE AIR FORCE RECONNAISSANCE AIRCRAFT RECENTLY FOUND A CENTRAL
PRESSURE OF 983 MB AND A PEAK FLIGHT LEVEL WIND OF 89 KT.  THESE
NUMBERS INDICATE HANNA HAS CONTINUED TO STRENGTHEN IN THE FACE OF
WHAT APPEARS TO BE STRONG NORTHERLY SHEAR...AND THE INITIAL
INTENSITY IS INCREASED TO 70 KT.  THE INTENSITY FORECAST REMAINS
DIFFICULT SINCE GLOBAL MODES SHOW THE SHEAR REMAINING STRONG OR
POSSIBLY INCREASING DURING THE NEXT COUPLE OF DAYS.  GIVEN HANNA'S
TENACITY THUS FAR...THE OFFICIAL FORECAST PRESUMES THAT HANNA WILL
BE ABLE TO FIGHT OFF THE SHEAR.  AT DAY 5...HANNA IS FORECAST TO BE
INLAND SO WEAKENING IS SHOWN.  

THE LAST FEW FIXES FROM THE AIRCRAFT INDICATE THAT HANNA HAS BEEN
MEANDERING.  HOWEVER...A 12-HOUR AVERAGE MOTION IS SOUTH-
SOUTHWESTWARD AT ABOUT 4 KT AND THIS WILL BE THE INITIAL MOTION
ESTIMATE.  WITH THE SUBTROPICAL RIDGE NORTH OF HANNA NOW
DISSIPATED...THE CYCLONE'S MOTION DURING THE NEXT COUPLE OF DAYS IS
EXPECTED TO BE SLOW AND POSSIBLY ERRATIC.   AFTER THAT...GLOBAL
MODELS SHOW THE SUBTROPICAL RIDGE BUILDING BACK OVER THE
WEST-CENTRAL ATLANTIC...AND THIS SHOULD CAUSE HANNA TO TURN
NORTHWEST WITH AN INCREASE IN FORWARD SPEED.  THERE IS STILL SOME
SPREAD AMONG THE VARIOUS TRACK MODELS WITH POTENTIAL AREAS OF
IMPACT RANGING FROM SOUTH FLORIDA THROUGH THE CAROLINAS.  UNTIL
HANNA TAKES A MORE DEFINITIVE MOTION...IT WILL BE DIFFICULT TO BE
MORE SPECIFIC ABOUT THE POTENTIAL THREAT AREA.  ALL INTERESTS ALONG
THE SOUTHEASTERN UNITED STATES COASTS SHOULD MONITOR THE PROGRESS
OF THIS SYSTEM. 
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      01/2100Z 22.2N  72.6W    70 KT
 12HR VT     02/0600Z 21.9N  72.9W    75 KT
 24HR VT     02/1800Z 21.8N  73.5W    75 KT
 36HR VT     03/0600Z 22.1N  73.9W    75 KT
 48HR VT     03/1800Z 23.1N  74.5W    75 KT
 72HR VT     04/1800Z 27.0N  78.0W    85 KT
 96HR VT     05/1800Z 31.5N  81.0W    85 KT
120HR VT     06/1800Z 39.0N  80.5W    25 KT...INLAND
 
$$
FORECASTER RHOME/AVILA
 
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