Hurricane IGOR

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HURRICANE IGOR DISCUSSION NUMBER  29
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   AL112010
500 AM AST WED SEP 15 2010
 
IGOR HAS WEAKENED A LITTLE DURING THE PAST FEW HOURS.  ENHANCED
INFRARED SATELLITE IMAGES INDICATE THAT CLOUD TOPS HAVE WARMED OVER
THE WESTERN SEMICIRCLE AND THE EYE HAS COOLED.  IN ADDITION...AN
0352 UTC TRMM OVERPASS SHOWED THAT THE SOUTHWESTERN PORTION OF THE
EYEWALL HAS ERODED.  BASED ON THIS DEGRADED APPEARANCE AND A BLEND
OF SATELLITE INTENSITY ESTIMATES...THE INITIAL WIND SPEED IS
LOWERED TO 125 KT.  IGOR REMAINS IN A FAVORABLE ENVIRONMENT FOR
STRENGTHENING...SO INTERNAL DYNAMICS WILL LIKELY BE THE DOMINANT
FACTOR FOR THE FUTURE INTENSITY OF IGOR FOR THE NEXT COUPLE OF
DAYS.  THESE SMALL SCALE DYNAMICS...WHICH ARE NOT WELL
UNDERSTOOD...USUALLY CAUSE FLUCTUATIONS IN INTENSITY...AND THAT IS
REFLECTED IN THE OFFICIAL FORECAST.  SOUTHERLY WIND SHEAR IS
EXPECTED TO INCREASE IN 3 TO 4 DAYS...WHICH SHOULD CAUSE SOME
WEAKENING BY THAT TIME.
 
THE INITIAL MOTION IS 300/8...AND THE EYE OF IGOR IS ON THE PREVIOUS
FORECAST TRACK.  A CONTINUED WEST-NORTHWEST TO NORTHWEST MOTION IS
EXPECTED OVER THE NEXT COUPLE OF DAYS AS THE HURRICANE MOVES ALONG
THE SOUTHWESTERN SIDE OF A SUBTROPICAL RIDGE.  BEYOND THAT TIME...A
NORTH-NORTHWESTWARD AND THEN NORTHWARD MOTION WITH AN INCREASE IN
FORWARD SPEED IS FORECAST AS IGOR ROUNDS THE RIDGE AND MOVES INTO
A PRONOUNCED WEAKNESS.  IN GENERAL...THE NEW TRACK GUIDANCE HAS
SHIFTED A LITTLE TO THE EAST AT DAYS 4 AND 5...AND THE OFFICIAL
FORECAST IS NUDGED ONLY SLIGHTLY IN THAT DIRECTION.
 
REGARDLESS OF THE EXACT TRACK OF IGOR...THE LARGE WIND FIELD OF
THE HURRICANE IS EXPECTED TO BE VERY CLOSE TO OR NEAR BERMUDA
WITHIN THE NEXT 3 TO 4 DAYS.  INTERESTS ON BERMUDA SHOULD CONTINUE
TO MONITOR THE PROGRESS OF IGOR. 
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      15/0900Z 19.5N  54.5W   125 KT
 12HR VT     15/1800Z 20.2N  55.6W   130 KT
 24HR VT     16/0600Z 21.1N  57.0W   130 KT
 36HR VT     16/1800Z 21.9N  58.4W   125 KT
 48HR VT     17/0600Z 22.9N  60.2W   120 KT
 72HR VT     18/0600Z 25.8N  63.3W   110 KT
 96HR VT     19/0600Z 29.5N  65.0W   100 KT
120HR VT     20/0600Z 34.0N  64.5W    90 KT
 
$$
FORECASTER CANGIALOSI
 
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