Hurricane NORBERT

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HURRICANE NORBERT DISCUSSION NUMBER  12
NWS NATIONAL HURRICANE CENTER MIAMI FL       EP142014
200 AM PDT FRI SEP 05 2014

Norbert has changed little in organization during the past several
hours.  The hurricane continues to have a large central dense
overcast with cloud tops colder than -80C.  However, microwave data
shows that the convection under the overcast is asymmetric and
occurring mainly south of the center.  Subjective and objective
Dvorak estimates are unchanged and the initial intensity remains
80 kt.

The initial motion is a somewhat uncertain 330/7.  The cyclone is
expected to move generally northwestward around the southwestern
portion of a mid-level ridge over northern Mexico during the next
3 days or so. The track guidance for this part of the forecast has
changed little since the last advisory, with all of the models
and the official forecast keeping the center offshore of the Baja
California peninsula.  However, as mentioned in the previous
package, only a slight deviation to the right of the track would
bring hurricane-force winds to the coast.  After 3 days, there
continues to be a large spread in the guidance, with the GFS and
NAVGEM calling for Norbert to recurve toward the northeast, while
the ECMWF, UKMET, and Canadian models forecasting it to stall west
of the northern Baja California peninsula.  This part of the
forecast again compromises between these extremes by showing a slow
northward motion.

Norbert should weaken during the forecast period as it moves over
gradually decreasing sea surface temperatures and interacts with
land.  The new intensity forecast is similar to the previous
forecast in showing Norbert weakening to a tropical storm in about
48 hours and degenerating to a remnant low by 96-120 hours.  The
intensity forecast generally lies between the SHIPS model and the
intensity consensus.

Moisture from the remnants of Dolly and the Pacific ITCZ is being
advected northward by the outer circulation of Norbert across
northern Mexico and into the southwestern United States. This could
result in heavy rains and life-threatening flash flooding in these
areas during the next few days.  Please see information from your
local weather office for more details.


FORECAST POSITIONS AND MAX WINDS

INIT  05/0900Z 22.5N 111.4W   80 KT  90 MPH
 12H  05/1800Z 23.4N 112.2W   75 KT  85 MPH
 24H  06/0600Z 24.4N 113.3W   70 KT  80 MPH
 36H  06/1800Z 25.3N 114.6W   65 KT  75 MPH
 48H  07/0600Z 26.1N 115.8W   55 KT  65 MPH
 72H  08/0600Z 27.5N 117.5W   35 KT  40 MPH
 96H  09/0600Z 28.5N 118.0W   30 KT  35 MPH...POST-TROP/REMNT LOW
120H  10/0600Z 29.0N 118.0W   25 KT  30 MPH...POST-TROP/REMNT LOW

$$
Forecaster Beven

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