ZCZC MIATCDEP3 ALL
TTAA00 KNHC DDHHMM

HURRICANE JIMENA DISCUSSION NUMBER  10
NWS NATIONAL HURRICANE CENTER MIAMI FL       EP132015
800 PM PDT FRI AUG 28 2015

Jimena is rapidly intensifying.  Conventional satellite imagery
shows that the hurricane's well-defined eye has warmed and
contracted since the last advisory.  Its central dense overcast,
consisting of very cold cloud top temperatures, has also become
increasingly more symmetric.  Aside from Jimena's core features,
outer bands surrounding the cyclone have also increased and become
better defined.  Dvorak classifications were T5.5/102 kt from TAFB
and SAB at 0000 UTC and the latest UW-CIMSS ADT value is 6.2/120 kt.
A blend of these data are used to arrive at an intensity estimate of
110 kt, making Jimena the fourth major hurricane of the season.

The initial motion estimate is 275/10, although the cyclone appears
to have recently experienced a southward trochoidal wobble. Directly
underneath a subtropical ridge to the north, Jimena should maintain
a general westward course for the next 12 to 24 hours.  After that
time, Jimena's heading should become west-northwestward as it nears
a break in this ridge around 140W, created by a mid-level trough
extending southwestward from California.  A significant decrease in
forward speed is likely after 96 hours when the cyclone reaches the
weakness around 140W.  The track guidance is tightly clustered
through 3 days and is only slightly divergent after that time, with
the multi-model consensus trending southward during the last 24
hours from days 3 to 5.  The new track forecast has been nudged
slightly southward in the short term and a little bit more in the
extended range, following the trend in the guidance.

The rapid intensification phase that Jimena is undergoing is likely
to continue in the short term while it encounters relatively light
shear and moves over anomalously high oceanic heat content. These
very conducive large-scale factors for intensification suggest that
Jimena should reach a peak intensity of near category 5 strength in
about 24 hours or so.  The hurricane could remain around its peak
intensity through 48 hours, even though SHIPS model output shows
some drying of the lower to middle troposphere along Jimena's
track. However, it should be noted that intense hurricanes such as
Jimena frequently experience eyewall replacements that can cause
fluctuations in intensity, and their occurrence and evolution are
nearly impossible to predict. After about 2 days, a slow decay is
forecast since oceanic and atmospheric conditions will only
gradually become less conducive.  Jimena's continued strenghtening
has required an upward adjustment of the intensity forecast in the
short term, and the new forecast is in excellent agreement with the
statistical guidance as well as the FSU Superensemble output. The
new forecast then trends toward the multi-model consensus from days
3 to 5.

FORECAST POSITIONS AND MAX WINDS

INIT  29/0300Z 12.3N 124.2W  110 KT 125 MPH
 12H  29/1200Z 12.5N 125.5W  125 KT 145 MPH
 24H  30/0000Z 13.0N 127.4W  135 KT 155 MPH
 36H  30/1200Z 13.9N 129.5W  130 KT 150 MPH
 48H  31/0000Z 14.9N 131.9W  125 KT 145 MPH
 72H  01/0000Z 16.3N 136.6W  115 KT 130 MPH
 96H  02/0000Z 17.3N 139.8W  100 KT 115 MPH
120H  03/0000Z 18.0N 141.7W   85 KT 100 MPH

$$
Forecaster Kimberlain

NNNN