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TROPICAL DEPRESSION FOUR-E DISCUSSION NUMBER   4
NWS NATIONAL HURRICANE CENTER MIAMI FL       EP042016
900 AM MDT THU JUL 07 2016

Tropical Depression Four-E has not improved in organization since
the last advisory.  A small cluster of deep convection is located
near the low-level center, but otherwise widespread showers and
thunderstorms mainly within the eastern and southern portion of the
circulation are lacking banding characteristics.  The intensity
remains 30 kt based on Current Intensity estimates of 2.0 from TAFB
and SAB.

The cyclone is still moving west-northwestward, or 285/7 kt.  A
strong subtropical ridge, which extends from northern Mexico
westward to near 130W, is expected to maintain its strength and
remain stationary for at least the next 3 days.  This pattern is
forecast to drive the depression almost due westward between 24
and 72 hours.  By days 4 and 5, the ridge is expected to weaken a
bit, which should allow the cyclone to gain some latitude and turn
back toward the west-northwest.  The track models, particularly the
GFS and ECMWF, are very tightly clustered, with those two models
less than a degree apart at day 5.  The updated NHC track forecast
was nudged southward on days 4 and 5 to be closer to the GFS/ECMWF
consensus, but otherwise there is higher-than-normal confidence in
the track forecast for the entire 5-day period.

The key concern for the depression's intensity forecast is the cold
wake left behind by Hurricane Blas.  Based on the latest available
daily global SST analyses, the waters ahead of the depression have
cooled to 26.5 degrees Celsius or colder.  The official forecast
track for the depression intersects and remains very close to Blas's
track during the next 5 days, which would keep it over these
colder-than-normal waters for a significant amount of time.
Since the SHIPS guidance utilizes a weekly SST analysis, which is
showing ocean surface temperatures about 2 degrees too warm,
confidence in its output is somewhat low at the moment.  Vertical
shear and environmental moisture values appear conducive for
strengthening, so the NHC official intensity forecast still shows
intensification, but at a slower rate than indicated by many of the
intensity models.  The updated forecast is also a little lower than
the previous one, especially through 48 hours.

FORECAST POSITIONS AND MAX WINDS

INIT  07/1500Z 12.7N 110.8W   30 KT  35 MPH
 12H  08/0000Z 13.0N 111.9W   35 KT  40 MPH
 24H  08/1200Z 13.2N 113.5W   40 KT  45 MPH
 36H  09/0000Z 13.2N 115.2W   45 KT  50 MPH
 48H  09/1200Z 13.2N 117.0W   55 KT  65 MPH
 72H  10/1200Z 13.2N 120.6W   75 KT  85 MPH
 96H  11/1200Z 14.0N 124.5W   85 KT 100 MPH
120H  12/1200Z 16.0N 128.5W   90 KT 105 MPH

$$
Forecaster Berg

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