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HURRICANE EUGENE DISCUSSION NUMBER  20
NATIONAL WEATHER SERVICE MIAMI FL
2 AM PDT WED AUG 11 1999
 
SATELLITE INTENSITY ESTIMATES HAVE LOWERED ON EUGENE AND ARE NOW 77
AND 65 KT FROM TAFB AND SAB...RESPECTIVELY.  MOST OF THE CONVECTION
IS NOW EAST OF THE PRESUMED CENTER...PROMPTING SAB TO USE THE SHEAR
PATTERN IN ITS CLASSIFICATION.  OFFICIAL INTENSITY IS LOWERED TO 75
KT.  WITH LOW SHEAR FORECAST AND SUFFICIENT SSTS...THE OFFICIAL
FORECAST CALLS FOR ONLY MODEST ADDITIONAL WEAKENING DURING THE
FORECAST PERIOD...IN REASONABLE AGREEMENT WITH THE SHIPS INTENSITY
MODEL.

THE FORECAST TRACK PRESENTS SOMETHING OF A CHALLENGE.  ALL THE
GLOBAL MODELS BUILD A MID-LEVEL RIDGE AHEAD OF EUGENE...WITH THE
ECMWF AND UKMET SHOWING A BREAK IN THE RIDGE TO THE EAST OF HAWAII. 
THE AVN SHOWS A WEAKNESS NEAR THE ISLANDS...AND THE NOGAPS EXTENDS
THE RIDGE MUCH FARTHER TO THE WEST.  WHICH OF THESE VERIFIES GREATLY
DETERMINES THE THREAT OF EUGENE TO HAWAII.  ANOTHER FACTOR IS HOW
QUICKLY EUGENE SPINS DOWN.  A STRONGER STORM WILL LIKELY MOVE WITH
THE DEEP LAYER FLOW AND TRACK CLOSER TO THE ISLANDS...WHILE IF
EUGENE WEAKENS FASTER THAN FORECAST...IT SHOULD STAY WELL TO THE
SOUTH.  MOST OF THE GUIDANCE FOR THIS PACKAGE IS A LITTLE SOUTH OF
THE PREVIOUS SET OF MODEL RUNS AND THE OFFICIAL FORECAST IS NUDGED
SOUTH AS WELL...IN CLOSE AGREEMENT WITH THE GFDL AND THE BAM MODELS.
 
THE NOAA GULFSTREAM IV JET AIRCRAFT HAS BEEN TASKED TO FLY IN THE
ENVIRONMENT OF HURRICANE EUGENE ON THURSDAY AFTERNOON TO HELP
PROVIDE INFORMATION ON THE SYNOPTIC STEERING CURRENTS.

WITH EUGENE CROSSING PAST 140 DEGREES LONGITUDE...RESPONSIBILITY FOR
FUTURE ADVISORIES NOW PASSES TO THE CENTRAL PACIFIC HURRICANE
CENTER.

FRANKLIN
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL     11/0900Z 13.7N 139.8W    75 KTS
12HR VT     11/1800Z 13.7N 141.5W    75 KTS
24HR VT     12/0600Z 14.1N 143.8W    70 KTS
36HR VT     12/1800Z 14.7N 146.0W    65 KTS
48HR VT     13/0600Z 15.5N 148.0W    65 KTS
72HR VT     14/0600Z 16.5N 152.5W    60 KTS
 
 
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