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HURRICANE JIMENA DISCUSSION NUMBER  23
NWS NATIONAL HURRICANE CENTER MIAMI FL       EP132015
200 AM PDT TUE SEP 01 2015

Jimena has changed little since the previous advisory.  Microwave
data indicate that the hurricane has concentric eyewalls, and the
eye temperature has actually warmed a bit during the past few
hours.  Since the overall satellite presentation has changed
little, and Dvorak estimates are T6.0 from TAFB and SAB, the
initial intensity is held at 115 kt.

Jimena has an expansive outflow shield radiating outward 400 to 600
n mi in all directions from the center, and the UW-CIMSS shear
analysis is currently showing less than 5 kt of shear affecting the
hurricane.  The SHIPS guidance shows the shear staying 5 kt or less
for the next 48 hours, and less than 10 kt for the next 72 hours.
Sea surface temperatures gradually decrease ahead of Jimena, but
they are at least 26C for the entire forecast period.  Therefore,
there don't seem to be any egregiously hostile conditions during
the next few days to induce a quick weakening trend.  As has been
the case for days, the hurricane models show a gradual weakening
trend through the five-day period, while the GFS and ECMWF continue
to maintain a much stronger hurricane.  As a compromise between
these scenarios, the NHC intensity forecast lies near the top end
of the intensity guidance, or close to the SHIPS model.  This
forecast is a little higher than the previous official forecast.

The initial motion is 280/11 kt.  Jimena is expected to turn
west-northwestward toward a break in the subtropical ridge within
the next 12 hours, and then northwestward and north-northwestward by
days 3 through 5.  This forecast reasoning is unchanged from prior
advisories, but the track guidance envelope did shift a little west
after 48 hours on this cycle.  The updated NHC track is therefore
nudged westward as well and is close to the TVCN model consensus.

FORECAST POSITIONS AND MAX WINDS

INIT  01/0900Z 16.4N 139.1W  115 KT 130 MPH
 12H  01/1800Z 16.9N 140.5W  110 KT 125 MPH
 24H  02/0600Z 17.4N 141.8W  105 KT 120 MPH
 36H  02/1800Z 17.9N 142.7W  100 KT 115 MPH
 48H  03/0600Z 18.3N 143.4W   95 KT 110 MPH
 72H  04/0600Z 19.4N 144.4W   85 KT 100 MPH
 96H  05/0600Z 20.7N 145.2W   75 KT  85 MPH
120H  06/0600Z 22.5N 146.3W   65 KT  75 MPH

$$
Forecaster Berg

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