ZCZC MIATCDEP1 ALL
TTAA00 KNHC DDHHMM

HURRICANE ORLENE DISCUSSION NUMBER  20
NWS NATIONAL HURRICANE CENTER MIAMI FL       EP162016
200 PM PDT THU SEP 15 2016

It appears that Orlene is now responding to the very dry
mid-tropospheric environment.  The eye is no longer apparent on
visible satellite images, and the CDO is taking on a more ragged
appearance.  The advisory intensity is reduced to 65 kt based on a
blend of Dvorak Final-T and Current Intensity numbers.  Since the
tropical cyclone is expected to continue to move through an
unusually dry air mass, with 700-500 mb relative humidities on the
order of 20-25 percent, weakening should continue during the next
few days.  The official intensity forecast is similar to the SHIPS
model and the intensity model consensus.  It is quite possible that
the system will weaken more quickly than shown here, as suggested by
the ECMWF global model prediction.

The initial motion, 260/9 kt, is similar to the previous estimate.
There is not too much change to the previous official track
forecast.  A zonally-oriented mid-level ridge should keep Orlene on
a generally westward heading at a somewhat faster forward speed for
the next few days.  Later in the forecast period, a mid-level low
near 140W longitude should produce a weakness in the ridge and a
west-northwestward turn at a slower speed.  The official track
forecast is just a little bit south of the previous one, and close
to the dynamical model consensus.

FORECAST POSITIONS AND MAX WINDS

INIT  15/2100Z 19.8N 122.9W   65 KT  75 MPH
 12H  16/0600Z 19.6N 124.6W   60 KT  70 MPH
 24H  16/1800Z 19.4N 127.0W   55 KT  65 MPH
 36H  17/0600Z 19.3N 129.5W   50 KT  60 MPH
 48H  17/1800Z 19.3N 132.0W   45 KT  50 MPH
 72H  18/1800Z 19.3N 137.0W   35 KT  40 MPH
 96H  19/1800Z 19.5N 141.5W   30 KT  35 MPH
120H  20/1800Z 20.5N 145.0W   25 KT  30 MPH...POST-TROP/REMNT LOW

$$
Forecaster Pasch

NNNN