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Tropical Storm Eugene Discussion Number   2
NWS National Hurricane Center Miami FL       EP052017
900 PM MDT Fri Jul 07 2017

Eugene is gradually becoming better organized this evening, with
infrared and microwave satellite imagery showing a large band of
convection developing over the southeastern semicircle.  Various
satellite intensity estimates range from 30 to 45 kt, and the
initial intensity is increased to 40 kt in best agreement with the
CIMSS satellite consensus technique.

The initial motion is 315/8.  There is little change to either the
forecast philosophy or the forecast track since the previous
advisory.  A mid- to upper-level low moving westward from
northwestern Mexico and an upper-level low seen in water vapor
imagery near 19N 120W have created a weakness in the subtropical
ridge west of the Baja California peninsula.  This feature is
likely to persist through 120 h allowing Eugene to move steadily
northwestward into the weakness through the forecast period.  The
new forecast track is near the consensus models and the center of
the guidance envelope.

Eugene is currently in an environment of light shear and warm water
with good to excellent outflow in all directions.  The large-scale
models forecast the shear to remain light until the storm moves
over decreasing sea surface temperatures in about 48 h.  Based on
this, the intensity forecast calls for steady strengthening until 48
h, with the new forecast lying near the upper edge of the intensity
guidance.  It should be noted that the rapid intensification index
of the SHIPS model responds to the nearly ideal environment by
showing a better than a 50 percent chance of 25 kt of strengthening
during the next 24 h.  So, an alternative forecast scenario is for
rapid intensification if Eugene develops a well-defined inner core.
After 48 h, Eugene should weaken steadily to rapidly over the cooler
water, with the system now forecast to degenerate to a remnant low
over 21C sea surface temperatures by 120 h.


FORECAST POSITIONS AND MAX WINDS

INIT  08/0300Z 12.5N 111.6W   40 KT  45 MPH
 12H  08/1200Z 13.2N 112.5W   45 KT  50 MPH
 24H  09/0000Z 14.5N 113.7W   55 KT  65 MPH
 36H  09/1200Z 15.8N 114.9W   65 KT  75 MPH
 48H  10/0000Z 17.3N 116.1W   70 KT  80 MPH
 72H  11/0000Z 20.0N 118.5W   65 KT  75 MPH
 96H  12/0000Z 22.5N 121.0W   45 KT  50 MPH
120H  13/0000Z 25.0N 123.0W   30 KT  35 MPH...POST-TROP/REMNT LOW

$$
Forecaster Beven

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