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TROPICAL DEPRESSION EIGHT-E DISCUSSION NUMBER   1
NWS NATIONAL HURRICANE CENTER MIAMI FL       EP082016
300 PM MDT THU JUL 21 2016

An ASCAT-B pass at 1742Z showed that the area of low pressure
located well southwest of Mexico now has a well-defined center, and
the geostationary imagery shows a curved convective band wrapping
nearly halfway around the system.  Given this, the low is now
classified as a tropical cyclone.  The initial intensity is set to
30 kt based on the ASCAT data, which is also in agreement with the
latest Dvorak estimate from SAB.  The depression will be moving over
SSTs of 28C or higher for the next couple of days, but will also be
in a moderate easterly to northeasterly shear environment during
that time.  Given these conditions, gradual intensification is
forecast in the short term.  The cyclone is forecast to peak in
about 72 hours before it moves over cooler waters and into a more
stable environment, which should result in slow weakening.  The NHC
intensity prediction is close to the intensity consensus through the
forecast period.

The initial motion estimate is a somewhat uncertain 290/10 given the
recent formation of the system.  The dominant steering mechanism for
the first 2-3 days of the forecast period will be a large
subtropical ridge that will migrate westward from central North
America over the eastern Pacific.  This should keep the cyclone
moving generally west-northwestward for the first 48 hours or so.
After that time, there is an increase in the spread of the guidance.
The ECMWF and HWRF show the cyclone turning more poleward into a
weakness in the ridge caused by an upper-level low, with the ECMWF
showing some northward motion possibly due to the influence of
Tropical Storm Fred to the the northeast.  The GFS, GEFS mean, and
COAMPS-TC show a more westward track with the cyclone staying south
of the ridge.  For now the NHC track forecast is down the middle of
the guidance envelope and is very close to the multi-model
consensus.  Given the large spread in the guidance, the track
forecast uncertainty is higher than usual late in the forecast
period.

FORECAST POSITIONS AND MAX WINDS

INIT  21/2100Z 10.8N 114.0W   30 KT  35 MPH
 12H  22/0600Z 11.4N 115.5W   35 KT  40 MPH
 24H  22/1800Z 12.3N 117.6W   45 KT  50 MPH
 36H  23/0600Z 13.0N 119.9W   50 KT  60 MPH
 48H  23/1800Z 13.6N 122.0W   60 KT  70 MPH
 72H  24/1800Z 15.0N 125.0W   65 KT  75 MPH
 96H  25/1800Z 17.0N 128.0W   55 KT  65 MPH
120H  26/1800Z 18.0N 130.0W   50 KT  60 MPH

$$
Forecaster Brennan

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