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WTPZ43 KNHC 311445

800 AM PDT MON AUG 31 2015

Jimena continues to be a powerful hurricane.  Recent microwave data
and infrared satellite images suggest that the system still has
concentric eyewalls.  The eye of the hurricane remains distinct and
has a diameter of about 20 n mi, and the convective pattern is
slightly asymmetric with cloud tops slightly warmer west of the eye.
Satellite intensity estimates were all 6.5 on the Dvorak scale,
therefore, the initial wind speed remains 130 kt.

The hurricane is now moving westward at about 14 kt steered by a
mid-level high pressure system to the north of the cyclone.  This
ridge is expected to break down during the next couple of days
while a trough deepens near the west coast of the United States.
This pattern evolution should weaken the steering currents for
Jimena, causing a gradual slow down and a turn to the northwest
during the next several days.  The track model guidance is in good
agreement on this scenario, and only minor tweaks were made to the
previous track forecast.  The new NHC track prediction lies close
to the various consensus aids.

Jimena is expected to more or less maintain its intensity during
the next day or so while it remains over 28 deg C water and in a
very low wind shear environment.  Fluctuations in strength are
possible during that time due to the ongoing eyewall cycles.  After
that time, a slow weakening is expected while water temperatures
lower along the forecast track.  The NHC intensity forecast lies on
the high side of the guidance and is a little above the previous
intensity forecast, giving some weight to the global models which
maintain a very strong cyclone for the next several days.


INIT  31/1500Z 15.6N 135.3W  130 KT 150 MPH
 12H  01/0000Z 16.0N 137.1W  125 KT 145 MPH
 24H  01/1200Z 16.6N 138.9W  125 KT 145 MPH
 36H  02/0000Z 17.3N 140.3W  115 KT 130 MPH
 48H  02/1200Z 17.8N 141.2W  105 KT 120 MPH
 72H  03/1200Z 18.9N 142.5W   95 KT 110 MPH
 96H  04/1200Z 19.9N 143.2W   85 KT 100 MPH
120H  05/1200Z 20.9N 143.8W   75 KT  85 MPH

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