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Hurricane Norman Discussion Number  13
NWS National Hurricane Center Miami FL       EP162018
200 AM PDT Fri Aug 31 2018

Norman appears to have weakened over the past several hours. Cloud
tops around the eye have warmed, and the eye itself has become less
distinct. Several recent microwave overpasses show little indication
that an eyewall replacement cycle is underway, but it is possible
that our ability to observe such a cycle is limited by the
resolution of the available instruments. Satellite intensity
estimates from all agencies have decreased and supported at most an
intensity of 125 kt at 0600 UTC. Given the continued warming of
cloud tops near the inner core since that time, the initial
intensity has been lowered to 120 kt.

Due to the lower initial intensity, the intensity forecast has also
been lowered slightly, particularly for the first 24 h. Gradual
weakening is expected through the forecast period, though larger
short-term fluctuations in intensity due to eyewall replacement
cycles are possible, if not likely, while Norman remains a
hurricane. By the end of the forecast period, a faster weakening
rate is anticipated as Norman is forecast to move over cooler SSTs
and reach a drier environment. The NHC forecast is near the center
of the intensity guidance envelope and near the intensity consensus.

The hurricane has continued to move west-southwestward at 8 kt.
Almost no change has been made to the track forecast, which remains
close to the various consensus aids. The hurricane should turn
westward, and then west-northwestward, as it is steered primarily by
a deep-layer ridge to the north for the next 5 days. With the
exception of the UKMET global model, which is an outlier to the
south, the global and regional dynamical models are in good
agreement on the future path of Norman, and confidence in the track
forecast is fairly high.


FORECAST POSITIONS AND MAX WINDS

INIT  31/0900Z 16.9N 120.2W  120 KT 140 MPH
 12H  31/1800Z 16.6N 121.4W  110 KT 125 MPH
 24H  01/0600Z 16.3N 123.1W  110 KT 125 MPH
 36H  01/1800Z 16.3N 125.1W  105 KT 120 MPH
 48H  02/0600Z 16.7N 127.4W  100 KT 115 MPH
 72H  03/0600Z 18.4N 133.0W   85 KT 100 MPH
 96H  04/0600Z 19.5N 139.0W   70 KT  80 MPH
120H  05/0600Z 20.5N 143.5W   55 KT  65 MPH

$$
Forecaster Zelinsky

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