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Tropical Storm Norman Discussion Number 3
NWS National Hurricane Center Miami FL EP162018
900 PM MDT Tue Aug 28 2018
The tropical cyclone has become significantly better organized over
the past several hours. A band of very cold-topped convection now
spirals well over halfway around the circulation. Dvorak T-numbers
from both TAFB and SAB are up to 3.0, which corresponds to a
current intensity of 45 kt. On this basis the system is being
upgraded to a tropical storm, making Norman the fourteenth named
tropical cyclone of this busy eastern North Pacific hurricane
season. Since Norman will continue to move over warm waters and
through an environment of low vertical shear and moist mid-level
air, continued strengthening is likely. In fact, the various Rapid
Intensification (RI) Indices show high probabilities of RI.
Therefore the official forecast shows intensity changes of 30 and 35
kt per day from 0-24 hours and 24-48 hours respectively. This is
also close to the simple intensity consensus but below the HFIP
Corrected Consensus and the latest HWRF model run.
The most recent geostationary and microwave satellite center fixes
indicate that Norman is located a little south and southwest of the
previous track, but the initial motion estimate remains about the
same as before, 290/9 kt. The cyclone is moving along the southern
periphery of a large mid-level ridge which is expanding westward.
This should cause the system to turn toward the west very soon.
Later in the period, the ridge builds a little to the southwest and
this will likely cause Norman to turn toward the west-southwest.
The official track forecast is a little south of the previous one,
but close to the latest simple and corrected model consensus
FORECAST POSITIONS AND MAX WINDS
INIT 29/0300Z 17.5N 113.9W 45 KT 50 MPH
12H 29/1200Z 17.9N 115.2W 60 KT 70 MPH
24H 30/0000Z 18.2N 117.0W 75 KT 85 MPH
36H 30/1200Z 18.3N 118.6W 90 KT 105 MPH
48H 31/0000Z 18.1N 120.3W 110 KT 125 MPH
72H 01/0000Z 17.2N 124.1W 110 KT 125 MPH
96H 02/0000Z 16.0N 128.0W 100 KT 115 MPH
120H 03/0000Z 16.0N 132.0W 90 KT 105 MPH