Tropical Storm EUGENE

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TROPICAL STORM EUGENE DISCUSSION NUMBER   3
NWS NATIONAL HURRICANE CENTER MIAMI FL       EP052011
200 PM PDT SUN JUL 31 2011
 
THE SATELLITE PRESENTATION OF EUGENE HAS IMPROVED SINCE THIS
MORNING...WITH THE APPEARANCE OF INCREASED BANDING AND THE
FORMATION OF A RAGGED CENTRAL DENSE OVERCAST.  DVORAK SATELLITE
ESTIMATES ARE T2.5 FROM SAB AND TAFB AT 1800 UTC.  A TIMELY ASCAT
PASS FROM 1810 UTC SUPPORTS AN INITIAL INTENSITY OF 40 KT.
 
THE ASCAT PASS WAS HELPFUL IN LOCATING THE CENTER...AND THE INITIAL
MOTION IS ESTIMATED TO BE 280/8...SLIGHTLY TO THE LEFT OF THE
PREVIOUS ESTIMATE. EUGENE REMAINS EMBEDDED IN AN EAST-
SOUTHEASTERLY FLOW SOUTH OF A DEEP-LAYER ANCTICYCLONE ANCHORED OVER
THE SOUTH CENTRAL UNITED STATES AND NORTHERN MEXICO. THIS FEATURE
SHOULD INDUCE A GENERAL WEST-NORTHWESTERWARD TRACK THROUGH THE
FORECAST PERIOD. EXCEPT FOR THE HWRF...THE TRACK GUIDANCE HAS
SHIFTED TO THE LEFT THIS CYCLE...FOLLOWING THE LEAD OF EARLIER RUNS
OF THE UKMET/ECMWF. THE NHC OFFICIAL FORECAST HAS BEEN ADJUSTED IN
THIS DIRECTION AND IS CLOSE TO THE TVCN MODEL CONSENSUS.
 
UW-CIMSS AND SHIPS SHEAR ANALYSES CONTINUE TO DIAGNOSE MODERATE
EASTERLY SHEAR OVER THE CYCLONE...WHICH IS FORECAST TO PERIST
THROUGH AT LEAST 48 HOURS. THE INTENSITY GUIDANCE FAVORS A GRADUAL
INTENSIFICATION OF THE CYCLONE IN SPITE OF THE SHEAR...AND THE
OFFICIAL NHC INTENSITY FORECAST CALLS FOR EUGENE TO REACH HURRICANE
STRENGTH WITHIN 48 HOURS. AFTER THAT...THE SHEAR IS EXPECTED TO
DECREASE FOR A DAY OR TWO BEFORE EUGENE REACHES PROGRESSIVELY
COOLER WATERS LATE IN THE FORECAST PERIOD...POSSIBLY OFFERING AN
OPPORTUNITY FOR ADDITIONAL INTENSIFICATION BEYOND WHAT IS SHOWN IN
THE OFFICIAL FORECAST. THE INTENSITY FORECAST IS ADJUSTED UPWARD
DUE TO THE SOUTHWARD SHIFT IN THE TRACK AND THE FORECAST OF A
LONGER PERIOD OF LOWER WIND SHEAR BETWEEN 48-96 HR. THIS FORECAST
IS IN BEST AGREEMENT WITH THE IVCN INTENSITY CONSENSUS AND FSSE
MODELS.
 

FORECAST POSITIONS AND MAX WINDS
 
INIT  31/2100Z 11.0N 101.1W   40 KT  45 MPH
 12H  01/0600Z 11.5N 102.9W   50 KT  60 MPH
 24H  01/1800Z 12.2N 104.8W   55 KT  65 MPH
 36H  02/0600Z 12.9N 106.6W   60 KT  70 MPH
 48H  02/1800Z 13.6N 108.4W   65 KT  75 MPH
 72H  03/1800Z 14.5N 111.5W   70 KT  80 MPH
 96H  04/1800Z 16.0N 114.5W   65 KT  75 MPH
120H  05/1800Z 17.5N 117.5W   45 KT  50 MPH
 
$$
FORECASTER KIMBERLAIN
 
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