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Tropical Storm Aletta Discussion Number 3
NWS National Hurricane Center Miami FL EP022018
900 AM MDT Wed Jun 06 2018
The cloud pattern of the storm is gradually becoming better
organized, but most of the deep convection is confined to the
eastern and southern portions of the circulation. Cirrus cloud
motions suggest that the upper-level outflow is slightly restricted
over the northwest quadrant, but vertical shear is not very strong
over the system. Dvorak intensity estimates from both TAFB and SAB
are unchanged from the previous synoptic time so the current
intensity is held at 40 kt for this advisory. Since Aletta should
remain over warm waters with modest shear over the next several
days, strengthening is likely. The model guidance is not very
bullish on intensification, however. Given the apparently
favorable environment, the official forecast is at the high end of
the guidance.
Based on a recent GMI microwave image, the center is repositioned a
little to the north of the previous track. This gives an
estimated initial motion of 280/6 kt. A mid-level ridge extending
from Mexico into the eastern Pacific should induce a westward or
slightly north of west motion over the next several days. The
latest GFS and its ensemble mean are on the northern side of the
track guidance envelope and the ECMWF forecast is near the southern
side. The official forecast essentially splits the difference and
lies quite close to the dynamical model consensus, and is not much
different from the previous NHC track.
FORECAST POSITIONS AND MAX WINDS
INIT 06/1500Z 14.7N 107.1W 40 KT 45 MPH
12H 07/0000Z 14.8N 108.0W 50 KT 60 MPH
24H 07/1200Z 15.0N 109.2W 55 KT 65 MPH
36H 08/0000Z 15.2N 110.4W 65 KT 75 MPH
48H 08/1200Z 15.4N 111.4W 75 KT 85 MPH
72H 09/1200Z 16.0N 113.3W 80 KT 90 MPH
96H 10/1200Z 17.0N 115.0W 60 KT 70 MPH
120H 11/1200Z 18.0N 117.0W 40 KT 45 MPH
$$
Forecaster Pasch
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