Tropical Depression FOUR-E

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TROPICAL DEPRESSION FOUR-E DISCUSSION NUMBER   1
NWS NATIONAL HURRICANE CENTER MIAMI FL       EP042014
200 PM PDT SAT JUN 28 2014

Satellite images indicate that the area of low pressure southwest
of Mexico has enough banded convective organization and center
definition to be declared a tropical cyclone.  The initial intensity
is set to 30 kt, in agreement with an ASCAT-B pass from 1602 UTC.

The large-scale environment looks favorable for strengthening, with
an upper-level anticyclone located just east of the center, along
with plenty of warm water.  However, the depression has a rather
large circulation envelope and radius of maximum winds, which could
preclude anything more than gradual strengthening.  Guidance is
split, with the LGEM/SHIPS showing a strong tropical storm, while
the HWRF/GFDL keep the system weaker through the first few days of
the forecast.  The NHC prediction is a little below the intensity
consensus at first to account for the initial structure, then is
above the consensus on Days 2/3 under the assumption the system
eventually consolidates.  Some weakening seems likely at longer
ranges due to cooler waters and possible dry air aloft.

The initial motion of the cyclone is 295/10.  A ridge currently
over the eastern Pacific and northern Mexico is forecast to build
eastward and strengthen over the next couple of days, which should
cause the cyclone to accelerate and take a slight leftward bend by
Monday.  The guidance is in good agreement and the NHC track
forecast is close to the model consensus during this time.
Afterward, there is much uncertainty in the forecast due to
a possible interaction with invest EP97 to the east, along with the
ridge likely weakening along 120W.  The model solutions become
rather divergent, ranging from a slow southward motion from the
HWRF/GFDL to a moderate westward motion from the ECMWF/GEFS.  The
NHC forecast at long range will show a slow westward course,
more in line with the ECMWF/GEFS solutions, and is west of the
track consensus.

FORECAST POSITIONS AND MAX WINDS

INIT  28/2100Z 14.5N 105.8W   30 KT  35 MPH
 12H  29/0600Z 15.3N 107.5W   30 KT  35 MPH
 24H  29/1800Z 16.1N 110.5W   40 KT  45 MPH
 36H  30/0600Z 16.7N 113.1W   45 KT  50 MPH
 48H  30/1800Z 17.1N 114.9W   50 KT  60 MPH
 72H  01/1800Z 17.5N 116.5W   50 KT  60 MPH
 96H  02/1800Z 17.5N 118.0W   45 KT  50 MPH
120H  03/1800Z 17.5N 120.0W   40 KT  45 MPH

$$
Forecaster Blake

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