000
WTPZ42 KNHC 092031
TCDEP2

Hurricane Aletta Discussion Number  17
NWS National Hurricane Center Miami FL       EP022018
300 PM MDT Sat Jun 09 2018

Aletta has rapidly weakened during the past several hours, with the
main convection currently dissipating to the north and northeast of
the now-exposed low-level center.  The initial intensity is reduced
to a possibly generous 65 kt based on a combination of subjective
and objective satellite intensity estimates.  Rapid weakening should
continue due to a combination of shear, decreasing sea surface
temperatures along the forecast track, and entrainment of dry air.
Based on current trends, the new intensity forecast shows a faster
demise for Aletta than the previous advisory, with the system now
forecast to weaken to a depression by 36 h, and degenerate to a
remnant low by 48 h.

The initial motion is quite uncertain due to Aletta being south of
where the earlier microwave fixes indicated it to be and due to the
exposed center moving southwestward.  This advisory will use a
longer-term motion of 275/5.  Most of the track guidance forecasts
the cyclone to resume a west-northwestward motion over the next few
hours, then again turn westward by 24-36 h.  After that time the
remnants of Aletta are expected to move slowly west-southwestward.
The new forecast track follows this basic scenario, but it lies well
to the south of the center of the guidance envelope and the
consensus models based on the current trends.  An alternate scenario
is that Aletta never makes the west-northwestward turn, which would
result in the decaying system tracking south of the new forecast
track.


FORECAST POSITIONS AND MAX WINDS

INIT  09/2100Z 16.1N 113.9W   65 KT  75 MPH
 12H  10/0600Z 16.6N 114.7W   50 KT  60 MPH
 24H  10/1800Z 17.0N 115.7W   35 KT  40 MPH
 36H  11/0600Z 17.1N 117.0W   25 KT  30 MPH
 48H  11/1800Z 16.9N 118.2W   20 KT  25 MPH...POST-TROP/REMNT LOW
 72H  12/1800Z 16.6N 120.0W   20 KT  25 MPH...POST-TROP/REMNT LOW
 96H  13/1800Z 16.0N 121.5W   20 KT  25 MPH...POST-TROP/REMNT LOW
120H  14/1800Z 15.5N 122.5W   15 KT  15 MPH...POST-TROP/REMNT LOW

$$
Forecaster Beven