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Tropical Depression FOURTEEN-E


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TROPICAL DEPRESSION FOURTEEN-E DISCUSSION NUMBER   6
NWS NATIONAL HURRICANE CENTER MIAMI FL       EP142015
900 PM MDT TUE SEP 01 2015

The depression is no better organized than it was earlier today.
Satellite imagery shows the cyclone with a couple of loosely
organized bands without much curvature over the eastern half of
circulation.  This assymetric and disorganized cloud pattern is
indicative of southwesterly shear induced by a mid- to upper-level
tropospheric trough to the northwest of the depression. The initial
intensity estimate is 30 kt, based on a blend of the latest Dvorak
estimates.

A relative reduction in vertical shear is forecast in 24 to 36
hours, when the trough to the west of the depression shears out. All
other factors being equal at that time, this should present the
cyclone with a limited opportunity for intensification. After 48
hours, the cyclone should meet a harsh environment of very dry air
and southwesterly shear associated with an unusually deep trough
digging along the U.S. west coast.  The global models indicate that
the shear should be strong enough that the low- to mid-level
circulations separate in about 72 hours, with dissipation by day 5.
The intensity guidance has decreased across the board, and the new
intensity forecast shows less intensification but still with a peak
in 24 to 36 hours.  This new forecast, however, is higher than the
statistical-dynamical guidance.

The depression's center is difficult to locate, but a blend of the
latest fixes and a continuity provide an initial motion estimate of
325/08.  A south-southeasterly to southerly steering flow between a
subtropical ridge over Mexico and the trough to the west should
cause the depression to gradually turn northward in 24 to 36 hours.
Once the cyclone crosses 20N, strong southwesterly flow ahead of
the amplifying western U.S. trough should cause recurvature.
However, the decoupling of the system will leave the low-level
center behind, moving slowly northeastward. By day 4, the remnant
low should drift erratically and then turn southward in the
low-level flow until dissipation.  The new track forecast is a
little slower than the previous one based on a blend of the GFS and
ECWMF model solutions.


FORECAST POSITIONS AND MAX WINDS

INIT  02/0300Z 14.3N 114.6W   30 KT  35 MPH
 12H  02/1200Z 15.7N 115.1W   35 KT  40 MPH
 24H  03/0000Z 17.3N 115.5W   40 KT  45 MPH
 36H  03/1200Z 18.8N 115.5W   40 KT  45 MPH
 48H  04/0000Z 20.1N 115.0W   35 KT  40 MPH
 72H  05/0000Z 22.0N 114.2W   25 KT  30 MPH
 96H  06/0000Z 22.8N 114.2W   20 KT  25 MPH...POST-TROP/REMNT LOW
120H  07/0000Z...DISSIPATED

$$
Forecaster Kimberlain

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