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TROPICAL DEPRESSION THIRTEEN-E DISCUSSION NUMBER   2
NWS NATIONAL HURRICANE CENTER MIAMI FL       EP132015
900 PM MDT WED AUG 26 2015

The cloud pattern of the depression has improved significantly
since the previous advisory with the establishment of a
well-defined outflow pattern and several curved convective banding
features. However, the inner-core convection is rather paltry and
limited at this time, and that is the main reason why the system is
still a depression despite is otherwise impressive satellite
appearance. The initial intensity of 30 kt is based on a Dvorak
satellite classification of T2.0/30 kt from TAFB.

The initial motion estimate of 285/15 kt is based on recent
microwave satellite fixes. There is no significant change to the
previous forecast track or reasoning. The cyclone is expected to
remain south of a deep-layer ridge located over northern Mexico and
the adjacent Pacific Ocean, and move generally westward along the
southern periphery of the ridge for the next 3-4 days. By 96-120
hours, the western portion of the ridge is forecast to weaken as a
mid-latitude trough drops southward, forcing the cyclone to move on
a slower west-northwestward track. The NHC track guidance remains in
good agreement on this developing scenario, and the official
forecast is similar to the previous advisory track and follows the
consensus models GFEX and TVCE.

The environment ahead of the depression is expected to be quite
favorable for strengthening for the next 5 days or so due to low
vertical wind shear, SSTs greater than 29 deg C, and moist
mid-level air. Both the SHIPS and LGEM models remain fairly
aggressive by making the cyclone to category 3 or 4 hurricane,
respectively, by days 4 and 5. Given these favorable conditions and
the recent improvement in the depression's structure, the official
intensity forecast has been nudged upward from the previous
advisory, and follows the IVCN consensus model through 96 hours,
and uses a blend of the SHIPS and LGEM models at 120 hours.

FORECAST POSITIONS AND MAX WINDS

INIT  27/0300Z 11.7N 114.8W   30 KT  35 MPH
 12H  27/1200Z 12.1N 116.9W   40 KT  45 MPH
 24H  28/0000Z 12.5N 119.3W   55 KT  65 MPH
 36H  28/1200Z 12.7N 121.6W   60 KT  70 MPH
 48H  29/0000Z 12.9N 123.7W   75 KT  85 MPH
 72H  30/0000Z 13.0N 127.5W   90 KT 105 MPH
 96H  31/0000Z 13.9N 131.3W  105 KT 120 MPH
120H  01/0000Z 15.5N 134.9W  110 KT 125 MPH

$$
Forecaster Stewart

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