Hurricane EUGENE

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HURRICANE EUGENE DISCUSSION NUMBER  18
NWS NATIONAL HURRICANE CENTER MIAMI FL       EP052011
800 AM PDT THU AUG 04 2011
 
COLDER CLOUD TOPS DEVELOPED AROUND THE EYE SEVERAL HOURS AGO...AND
SUBJECTIVE DVORAK CURRENT INTENSITY ESTIMATES AT 1200 UTC WERE 115
KT AND 102 KT FROM TAFB AND SAB...RESPECTIVELY.  IN ADDITION...
OBJECTIVE ADT ESTIMATES FROM UW-CIMSS INCREASED BACK UP TO 115 KT
AFTER 0800 UTC.  A BLEND OF THESE NUMBERS SUGGESTS AN INITIAL
INTENSITY OF 105 KT.
 
THE INITIAL MOTION IS STILL 285/12 AND SHOULD REMAIN ESSENTIALLY
UNCHANGED FOR THE NEXT 48 HOURS AS EUGENE CONTINUES TO BE STEERED
BY THE MID-LEVEL RIDGE...WHOSE AXIS IS ALONG 28N.  THE TRACK
GUIDANCE HAS SHIFTED A LITTLE TO THE SOUTH...AND THE NEW OFFICIAL
FORECAST LIES CLOSE TO THE MULTI-MODEL CONSENSUS TVCE.  EUGENE
SHOULD SLOW DOWN BY DAYS 3 AND 4 AS THE WEAKENED CYCLONE IS STEERED
BY WEAK LOW-LEVEL FLOW.

FOR THE FIRST TIME...THE SHIPS-DERIVED ANNULAR HURRICANE INDEX
INDICATES THAT EUGENE HAS GAINED ANNULAR CHARACTERISTICS...AND THE
SLOW WEAKENING OVER THE PAST 18 HOURS OR SO BEARS THIS OUT. 
TRUTHFULLY...THE PRESENTATION OF THE HURRICANE HAS DEGRADED SOMEWHAT
IN THE LAST FEW INFRARED AND MICROWAVE SATELLITE IMAGES...BUT IT
WILL TAKE A LITTLE TIME FOR THE DVORAK CI NUMBERS...AND PRESUMABLY
THE ACTUAL INTENSITY...TO DECREASE.  ALSO...SINCE THE FORECAST
TRACK HAS SHIFTED A LITTLE SOUTH...THE SEA SURFACE TEMPERATURES
ALONG THE TRACK WILL BE DECREASING MORE GRADUALLY AND COULD SUPPORT
SLOWER WEAKENING.  IN LIGHT OF THESE POINTS...THE OFFICIAL
INTENSITY FORECAST IS A BIT HIGHER THAN ALL THE GUIDANCE FOR THE
FIRST 12 HOURS AND THEN FOLLOWS THE HIGHEST OF THE MODELS...THE
LGEM...FOR THE REST OF THE FORECAST PERIOD.  EUGENE SHOULD
ULTIMATELY WEAKEN TO A REMNANT LOW BY DAY 4 OVER 22C DEGREE WATERS
AND DEGENERATE TO A TROUGH BY DAY 5...AS INDICATED IN THE GLOBAL
MODEL FIELDS.
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  04/1500Z 16.8N 118.9W  105 KT 120 MPH
 12H  05/0000Z 17.4N 120.8W   90 KT 105 MPH
 24H  05/1200Z 18.0N 123.2W   70 KT  80 MPH
 36H  06/0000Z 18.6N 125.6W   55 KT  65 MPH
 48H  06/1200Z 19.2N 127.8W   45 KT  50 MPH
 72H  07/1200Z 20.5N 131.5W   30 KT  35 MPH
 96H  08/1200Z 21.0N 134.0W   25 KT  30 MPH...POST-TROP/REMNT LOW
120H  09/1200Z...DISSIPATED
 
$$
FORECASTER BERG
 
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