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Tropical Storm ALETTA


Tropical Storm Aletta Discussion Number   2
NWS National Hurricane Center Miami FL       EP022018
300 AM MDT Wed Jun 06 2018

Deep convection has increased significantly during the past 12
hours, and the cloud pattern is better organized with the formation
of a few cyclonically curved bands. The outflow is fair in all
quadrants. An ASCAT pass a few hours ago, indicate that the winds
are between 35 to 40 kt, but these winds are confined to a band to
the east of the center.  On this basis, the depression has been
upgraded to Tropical Storm Aletta, the first named system of the
2018 eastern North Pacific season.

An prevailing environment of low shear favors intensification, and
although the Rapid Intensification Indices are not as high as
earlier, they are still on the high side. The NHC forecast calls for
Aletta to become a hurricane in 36 hours as indicated in the
previous forecast. After 3 days, when the cyclone reaches cooler
water and higher shear, a gradual weakening is anticipated.

It appears that Aletta is moving toward the west at about 6 kt
around the periphery of a subtropical ridge centered over
northwestern Mexico. However, a weakness in the ridge should cause
the cyclone to gradually gain some latitude during the next few days
with no significant change in forward speed. The NHC forecast
follows the model consensus, and it is basically centered in the
middle of the guidance envelope bounded by the GFS to the north
and the ECMWF to the south.


INIT  06/0900Z 14.1N 106.5W   40 KT  45 MPH
 12H  06/1800Z 14.2N 107.4W   45 KT  50 MPH
 24H  07/0600Z 14.4N 108.5W   55 KT  65 MPH
 36H  07/1800Z 14.6N 109.3W   65 KT  75 MPH
 48H  08/0600Z 15.0N 110.5W   75 KT  85 MPH
 72H  09/0600Z 15.5N 112.5W   80 KT  90 MPH
 96H  10/0600Z 16.5N 114.5W   70 KT  80 MPH
120H  11/0600Z 17.0N 116.0W   50 KT  60 MPH

Forecaster Avila