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Hurricane NORMAN


Hurricane Norman Discussion Number  25
NWS National Hurricane Center Miami FL       EP162018
200 AM PDT Mon Sep 03 2018

Its possible that Norman has peaked, perhaps permanently this time.
Cloud tops have notably warmed around the eye, which itself has
become less distinct in IR imagery overnight.  The initial intensity
has been lowered to 110 kt based on a blend of subjective Dvorak
final-T and CI numbers from TAFB and SAB, and the UW-CIMSS ADT.
Based on trends over the past hour or two, it's possible Norman has
weakened even more than indicated.  All of the intensity guidance
suggests that Norman should steadily weaken over the next several
days due to a combination of marginal SSTs, moderate shear, and a
drier surrounding environment, though this was the case last night
as well shortly before Norman quickly re-intensified to major
hurricane strength.  Since another sudden period of intensification
doesn't appear imminent, the new NHC intensity forecast is very
close to the consensus through day 5, and only minor changes were
made from the previous advisory.

The estimated initial motion is now 285/17 kt.  Norman should
continue moving very quickly toward the central Pacific over the
next 24 hours as it is steered by a strong subtropical ridge to the
north.  By later this week, all of the global models forecast
that the hurricane will slow down, and then turn toward the
northwest toward a weakness in the ridge.  There is still a fair
amount of spread in the track guidance, particularly regarding the
speed of Norman after it begins to turn northwestward around day 4
or 5, so confidence is in this portion of the track forecast is low.
The new NHC track forecast has been adjusted slightly south of the
previous advisory for the first 72 h, following the HCCA and TVCX
consensus aids, but is fairly similar after that.  Based on the
current forecast, Norman is expected to cross into the central
Pacific later today.


INIT  03/0900Z 19.0N 134.6W  110 KT 125 MPH
 12H  03/1800Z 19.5N 137.3W   95 KT 110 MPH
 24H  04/0600Z 20.0N 140.4W   85 KT 100 MPH
 36H  04/1800Z 20.2N 143.2W   80 KT  90 MPH
 48H  05/0600Z 20.4N 145.4W   75 KT  85 MPH
 72H  06/0600Z 21.2N 149.0W   70 KT  80 MPH
 96H  07/0600Z 23.5N 151.5W   60 KT  70 MPH
120H  08/0600Z 27.0N 153.5W   50 KT  60 MPH

Forecaster Zelinsky