Hurricane HECTOR

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HURRICANE HECTOR DISCUSSION NUMBER   8
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   EP092006
800 AM PDT THU AUG 17 2006
 
ENHANCED INFRARED IMAGERY DEPICTS THAT A CENTRAL DENSE OVERCAST
FEATURE HAS DEVELOPED DURING THE PAST 6 HOURS...WITH A
WELL-DEVELOPED WHITE BAND OVER THE EASTERN SEMICIRCLE OF THE
TROPICAL CYCLONE. DVORAK INTENSITY ESTIMATES HAVE INCREASED TO 77
KT AND 65 KT FROM TAFB AND SAB RESPECTIVELY...AND ADT CURRENT
INTENSITY ESTIMATES SUGGEST HECTOR IS SLIGHTLY STRONGER THAN 70 KT.
THE INITIAL INTENSITY IS INCREASED TO 75 KT. WATER VAPOR IMAGERY
INDICATES AN IMPRESSIVE OUTFLOW CHANNEL OVER THE SOUTHERN HALF OF
THE SYSTEM...WITH LIGHT UPPER-LEVEL EASTERLIES OVER THE REMAINING
PORTIONS. INTENSITY MODELS SUGGEST NO SIGNIFICANT CHANGES IN THE
ENVIRONMENT OVER THE NEXT 36 HOURS...THEREFORE...A LITTLE MORE
INTENSIFICATION IS FORECAST. AFTERWARD...GRADUAL WEAKENING IS
EXPECTED AS THE TROPICAL CYCLONE BEGINS TO MOVE OVER COOLER WATERS
AND WITHIN A LESS FAVORABLE THERMODYNAMIC ENVIRONMENT. BY DAY
3...MODELS CONTINUE TO INDICATE AN INCREASE IN SOUTHWESTERLY SHEAR
AS A MID- TO UPPER-LEVEL TROUGH MOVES NORTHEAST OF HAWAII...ALONG
140W. THIS SCENARIO COULD INFLUENCE RAPID WEAKENING THROUGH THE
REMAINDER OF THE FORECAST.
 
INITIAL MOTION IS ESTIMATED AT 290/11.  HECTOR IS ON THE
SOUTHWESTERN PERIPHERY OF A DEEP LAYER RIDGE EXTENDING OVER THE
EASTERN PACIFIC TO 27N130W FROM THE SOUTHWESTERN UNITED STATES. THE
SYSTEM SHOULD CONTINUE ON A GENERAL WEST-NORTHWESTWARD MOTION FOR
THE NEXT 48 HOURS...TURNING MORE NORTHWESTWARD THEREAFTER AS A
WEAKNESS IN THE RIDGE BECOMES MORE PRONOUNCED.  THE OFFICIAL
FORECAST FOLLOWS THIS SCENARIO...AND IS BASED ON A CONSENSUS OF THE
DYNAMICAL MODELS...WITH LESS EMPHASIS ON THE UKMET.
 
 
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      17/1500Z 14.7N 121.1W    75 KT
 12HR VT     18/0000Z 15.3N 122.8W    80 KT
 24HR VT     18/1200Z 16.2N 124.9W    80 KT
 36HR VT     19/0000Z 17.1N 126.9W    75 KT
 48HR VT     19/1200Z 18.0N 128.9W    70 KT
 72HR VT     20/1200Z 20.0N 132.0W    55 KT
 96HR VT     21/1200Z 21.5N 134.0W    35 KT
120HR VT     22/1200Z 22.5N 136.0W    25 KT
 
$$
FORECASTER ROBERTS/KNABB
 
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