Tropical Depression FOUR-E

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TROPICAL DEPRESSION FOUR-E DISCUSSION NUMBER   2
NWS NATIONAL HURRICANE CENTER MIAMI FL       EP042014
800 PM PDT SAT JUN 28 2014

Recent microwave images show that deep convection associated with
the depression is only loosely organized in bands while a new burst
of convection is developing about 100 nm north of the estimated
center.  Since the structure has not improved much since the last
advisory, the intensity is being held at 30 kt, which is supported
by a blend of the latest subjective and objective Dvorak estimates.

The depression is located to the south of an anomalously strong
mid-level ridge which runs east-west across northern Mexico and the
adjacent Pacific.  As a result, the depression is moving quickly to
the west-northwest with an initial motion of 285/12 kt.  Further
acceleration is anticipated in the next 12-24 hours as the
depression gets closer to the strongest part of the ridge.  After
24 hours, the ridge is forecast to shift westward and become
anchored near 25N 135W, which will tend to cause the depression to
slow down in the latter part of the forecast period.  The track
models are in generally good agreement in the eventual path of the
cyclone but do diverge on forward speed by days 3 through 5.  The
biggest outlier is the GFDL, which turns the depression
northeastward toward Mexico in response to a more significant break
in the ridge.  The GFDL solution is disregarded, and the updated
track forecast is relatively unchanged from the previous one.

Relatively low vertical shear, a moist environment, and warm sea
surface temperatures favor strengthening during the next few days.
Rapid intensification is not expected in the short term due to the
sprawling nature of the depression, but once the cyclone becomes
more consolidated, strengthening should be a little quicker.  The
updated NHC forecast shows a slightly faster strengthening rate
between 12-48 hours and is just under the SHIPS guidance.  By day 3,
a more stable and drier air mass, as well as cooler ocean water,
will likely end any intensification and then cause gradual weakening
by the end of the forecast period.

FORECAST POSITIONS AND MAX WINDS

INIT  29/0300Z 14.6N 107.4W   30 KT  35 MPH
 12H  29/1200Z 15.4N 109.5W   35 KT  40 MPH
 24H  30/0000Z 16.1N 112.2W   45 KT  50 MPH
 36H  30/1200Z 16.6N 114.1W   50 KT  60 MPH
 48H  01/0000Z 17.0N 115.3W   55 KT  65 MPH
 72H  02/0000Z 17.5N 117.0W   50 KT  60 MPH
 96H  03/0000Z 17.5N 118.0W   50 KT  60 MPH
120H  04/0000Z 17.5N 119.0W   45 KT  50 MPH

$$
Forecaster Berg

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