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HURRICANE ORLENE DISCUSSION NUMBER   6
NWS NATIONAL HURRICANE CENTER MIAMI FL       EP162016
200 AM PDT MON SEP 12 2016

Orlene continues to strength.  Satellite images indicate that the
relatively compact tropical cyclone has become better organized
since the previous advisory with an eye occasionally evident in
infrared images. Recent microwave data also indicate that the inner
core of the cyclone is better defined.  Dvorak classifications from
TAFB and SAB were 4.0/65 kt and 4.5/77 kt, respectively, and
automated values from CIMSS at the University of Wisconsin are
4.4/75 kt.  Based on these data, the initial wind speed is increased
to 70 kt, making Orlene a category 1 hurricane on the Saffir-Simpson
Hurricane Wind Scale.  Orlene has strengthened at a rapid rate of 35
kt during the past 24 hours.

The hurricane is moving northwestward, or 305 degrees, at 8 kt.  A
trough over the U.S. Pacific northwest is expected to dig southward
during the next day or two, causing a significant weakness in the
subtropical ridge.  This pattern change should cause Orlene to turn
northwestward or northward and slow down later today, and the
cyclone will likely come to a crawl in the 24-48-hour time period.
Beyond that time, the trough is expected to lift out allowing
ridging to become re-established to the north of the system.  This
should result in Orlene moving westward at a faster pace. The
models are in good agreement on this scenario, and the NHC track
forecast is largely an update of the previous one.

Additional strengthening seems likely during the next 24 hours
while the hurricane remains over warm water, and in an environment
of low wind shear and relatively moist conditions.  After that
time, a slow weakening should commence due to decreasing relative
humidity values and cooler water temperatures, likely aided by
cold water upwelling.  The NHC intensity forecast is near the high
end of the models, in best agreement with the LGEM and Florida
State Superensemble guidance, and is slightly higher than the
previous one in the short term.

FORECAST POSITIONS AND MAX WINDS

INIT  12/0900Z 17.1N 119.1W   70 KT  80 MPH
 12H  12/1800Z 17.7N 119.5W   80 KT  90 MPH
 24H  13/0600Z 18.5N 119.7W   90 KT 105 MPH
 36H  13/1800Z 19.0N 119.8W   85 KT 100 MPH
 48H  14/0600Z 19.2N 120.1W   80 KT  90 MPH
 72H  15/0600Z 19.2N 122.2W   70 KT  80 MPH
 96H  16/0600Z 18.9N 126.5W   65 KT  75 MPH
120H  17/0600Z 19.0N 131.5W   60 KT  70 MPH

$$
Forecaster Cangialosi

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