Hurricane HECTOR

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HURRICANE HECTOR DISCUSSION NUMBER   9
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   EP092006
200 PM PDT THU AUG 17 2006
 
SATELLITE IMAGERY FROM THIS AFTERNOON INDICATES A INTENSIFYING
CYCLONE WITH A WELL-DEFINED EYE HAVING FORMED OVER THE LAST FEW
HOURS. DVORAK INTENSITY ESTIMATES FROM SAB...TAFB...AND UW-CIMSS
ADT ARE UNANIMOUSLY BETWEEN 75 AND 80 KT. ADDITIONALLY...AN AMSU
INTENSITY ESTIMATE FROM AN OVERPASS AROUND 1400 UTC WAS 76 KT.  THE
INITIAL INTENSITY IS SET AT THE HIGH END OF THIS RANGE GIVEN THE
RECENT APPEARANCE OF AN EYE AND THE OVERALL IMPRESSIVE SATELLITE
SIGNATURE.
 
THE INTENSITY FORECAST REASONING IS A LITTLE MUDDIED BY THE CURRENT
DEVELOPMENT TREND.  NONE OF THE AVAILABLE INTENSITY GUIDANCE SHOWS
MUCH ADDITIONAL STRENGTHENING WITH THE SHIPS MODEL FORECASTING A
PEAK INTENSITY OF 85 KT...THE FSU SUPERENSEMBLE 83 KT...AND THE
GFDL 91 KT.  HOWEVER...IN THE SHORT-TERM...THERE ARE SEEMINGLY NO
SIGNIFICANT FEATURES WHICH MIGHT ARREST THE CURRENT UPWARD TREND.
WATER VAPOR IMAGERY SHOWS AN UPPER-LEVEL SHEAR AXIS AND LARGE
AREA OF DRY MIDDLE TO UPPER-LEVEL AIR TO THE WEST OF HECTOR.
HOWEVER...IN THE ABSENCE OF VERTICAL SHEAR...IT IS ASSUMED THE
CYCLONE WILL BE UNAFFECTED BY THIS DRY AIR. INDEED...SOME OF THE
GLOBAL MODELS SHOW THIS SHEAR AXIS WEAKENING OVER THE NEXT DAY OR
SO AS IT IS OBLITERATED BY THE OUTFLOW FROM HECTOR.  THE
OFFICIAL FORECAST IS AT THE UPPER END OF THE INTENSITY GUIDANCE
SPECTRUM AND IS VERY CLOSE TO THE GFDL MODEL...SHOWING HECTOR
BECOMING A CATEGORY TWO HURRICANE WITHIN THE NEXT 24 HOURS. BEYOND
DAY 2...THE FORECAST BECOMES A LITTLE MORE STRAIGHTFORWARD AS
HECTOR MOVES OVER PROGRESSIVELY COOLER WATERS... ULTIMATELY
RESULTING IN RAPID WEAKENING.
 
THE INITIAL MOTION IS ESTIMATED AT 285/11.  HECTOR CONTINUES TO MOVE
AROUND THE SOUTHWESTERN PERIPHERY OF A DEEP LAYER RIDGE EXTENDING
ACROSS NORTHERN MEXICO AND INTO THE EASTERN PACIFIC. THE HURRICANE
IS EXPECTED TO GRADUALLY TURN MORE NORTHWESTWARD AS IT APPROACHES A
WEAKNESS IN THE RIDGE FORECAST TO DEVELOP BETWEEN 125W AND 135W. 
THE OFFICIAL FORECAST IS ADJUSTED SLIGHTLY SOUTH BUT IS OTHERWISE
VERY SIMILAR TO THE PREVIOUS TRACK.
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      17/2100Z 15.0N 122.1W    80 KT
 12HR VT     18/0600Z 15.4N 123.7W    85 KT
 24HR VT     18/1800Z 16.2N 125.7W    90 KT
 36HR VT     19/0600Z 17.0N 127.7W    80 KT
 48HR VT     19/1800Z 17.9N 129.6W    70 KT
 72HR VT     20/1800Z 19.5N 132.5W    50 KT
 96HR VT     21/1800Z 21.0N 135.0W    30 KT
120HR VT     22/1800Z 22.5N 138.0W    25 KT...REMNANT LOW
 
$$
FORECASTER RHOME/KNABB
 
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