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Hurricane Olivia Discussion Number  18
NWS National Hurricane Center Miami FL       EP172018
200 AM PDT Wed Sep 05 2018

GOES-15 imagery and a recent METOP-B AMSU overpass indicate that
Olivia's eyewall has collapsed in the northwest quadrant.
Additionally, the eye temperature has warmed considerably.
Subjective and Objective T-numbers have decreased and support a
lowered intensity of 100 kt for this advisory.

Moderate easterly shear, gradually decreasing sea surface
temperatures, and drier, more stable air in the middle portions of
the atmosphere along the forecast track of the cyclone should
cause the hurricane to continue to slowly weaken.  The only
adjustment made to the NHC intensity forecast was a slight increase
at day 4 and 5 to agree more with the consensus intensity guidance.

Olivia's current motion is estimated to be westward, or 275/11 kt.
A building subtropical ridge over the eastern Pacific and to the
north of Olivia is should induce a westward and west-northwestward
with increasing forward speed during the next several days.
Toward the end of the forecast period, global models continue to
show a stronger ridge, and a turn back toward the west is shown
in the advisory.  The official forecast is similar to the forecast 6
hours ago, and is close to the NOAA-HCCA and TVCN, which are
typically better-performing guidance models.

FORECAST POSITIONS AND MAX WINDS

INIT  05/0900Z 16.9N 121.2W  100 KT 115 MPH
 12H  05/1800Z 17.2N 122.9W   95 KT 110 MPH
 24H  06/0600Z 17.8N 125.4W   90 KT 105 MPH
 36H  06/1800Z 18.6N 128.0W   85 KT 100 MPH
 48H  07/0600Z 19.6N 130.8W   80 KT  90 MPH
 72H  08/0600Z 21.3N 136.2W   65 KT  75 MPH
 96H  09/0600Z 22.2N 141.5W   60 KT  70 MPH
120H  10/0600Z 22.8N 146.2W   60 KT  70 MPH

$$
Forecaster Roberts

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