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HURRICANE GUILLERMO DISCUSSION NUMBER  12
NWS NATIONAL HURRICANE CENTER MIAMI FL       EP092015
200 PM PDT SAT AUG 01 2015


The cloud pattern has begun to deteriorate, but it is organized
enough to keep the same Dvorak T-numbers with an initial intensity
of 90 kt. Guillermo is heading toward a shear environment, and on
this basis, the NHC forecast calls for a gradual weakening. By the
time Guillermo approaches the Hawaiian Islands, the upper-level
winds are forecast to be even more unfavorable, and by then,
Guillermo is expected to have weakened to a tropical storm. The NHC
forecast continues to be very close to the intensity consensus model
ICON.

Guillermo is moving toward the west-northwest or 285 degrees at 12
kt.  The hurricane is already located on the southwestern edge of
the subtropical ridge, and there is a large weakness in the ridge to
its northwest. This pattern should force the cyclone to slow down
even further and turn more to the west-northwest or northwest. The
most reliable track models are now in better agreement, and the
multi-model consensus brings Guillermo just north or very near
the Hawaiian Islands.  The NHC forecast follows the consensus and is
very similar to the previous one.

Due to uncertainties in longer-range track predictions, it is
important for users not to focus on the exact track forecasts at 96
and 120 hours. Given the large spread of the models beyond 72
hours in this case, the forecast uncertainty is particularly high at
those time periods.

Since Guillermo is now moving into the Central Pacific, future
information will be provided by the Central Pacific Hurricane
Center at Honolulu, Hawaii.


FORECAST POSITIONS AND MAX WINDS

INIT  01/2100Z 13.8N 140.1W   90 KT 105 MPH
 12H  02/0600Z 14.3N 141.8W   85 KT 100 MPH
 24H  02/1800Z 15.1N 143.8W   75 KT  85 MPH
 36H  03/0600Z 15.9N 145.4W   65 KT  75 MPH
 48H  03/1800Z 16.7N 146.7W   60 KT  70 MPH
 72H  04/1800Z 18.2N 149.5W   55 KT  65 MPH
 96H  05/1800Z 19.7N 152.4W   50 KT  60 MPH
120H  06/1800Z 21.0N 155.5W   40 KT  45 MPH

$$
Forecaster Avila

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