Hurricane RACHEL

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HURRICANE RACHEL DISCUSSION NUMBER  18
NWS NATIONAL HURRICANE CENTER MIAMI FL       EP182014
200 PM PDT SUN SEP 28 2014

The cloud pattern of Rachel has not changed very much in visible
satellite imagery during the past several hours.  A ragged
banded-type eye has occasionally been evident in visible imagery
and recent microwave data has shown a similar feature.  The latest
Dvorak intensity estimates have decreased slightly so the initial
wind speed has been reduced to 65 kt.  Increasing southwesterly
vertical wind shear and a less favorable thermodynamic environment
are expected to cause steady weakening during the next couple of
days, and Rachel should weaken to a tropical depression in about
48 hours.  The cyclone is forecast to degenerate to a remnant
low shortly thereafter.  The updated NHC intensity forecast is
close to the multi-model consensus.

Rachel appears to be slowing down, with an initial motion estimate
of 340/4 kt.  The latest track guidance has become more divergent
with the GFS and HWRF taking Rachel more northward, then
northeastward in southwesterly flow between a mid-level ridge over
Mexico and a trough moving across the western United States. On the
other hand, the ECMWF and GFS ensemble mean show less of a poleward
motion as the cyclone weakens and become a more shallow system. The
NHC forecast leans toward the latter solution and shows Rachel
moving slowly northward during the next 24 hours, then turning
west-southwestward in the low-level flow after weakening occurs.
The new forecast is similar to, but a little slower than the
previous NHC advisory.

FORECAST POSITIONS AND MAX WINDS

INIT  28/2100Z 21.7N 117.4W   65 KT  75 MPH
 12H  29/0600Z 22.3N 117.5W   55 KT  65 MPH
 24H  29/1800Z 22.6N 117.6W   45 KT  50 MPH
 36H  30/0600Z 22.6N 117.7W   35 KT  40 MPH
 48H  30/1800Z 22.5N 117.8W   30 KT  35 MPH
 72H  01/1800Z 22.0N 118.3W   25 KT  30 MPH...POST-TROP/REMNT LOW
 96H  02/1800Z 22.0N 119.0W   20 KT  25 MPH...POST-TROP/REMNT LOW
120H  03/1800Z...DISSIPATED

$$
Forecaster Brown

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