Skip Navigation Links
NOAA NOAA United States Department of Commerce

Tropical Storm ORLENE


200 AM PDT SUN SEP 11 2016

There has been an impressive increase in the organization of the
depression's cloud pattern since the last advisory.  An ASCAT pass
indicates that the low-level center is located just inside what
appears to be a formative central dense overcast (CDO), whose cloud
top temperatures have cooled significantly.  A well-developed
convective band also spirals outward from the CDO, now covering much
of the western semicircle of the circulation. The earlier ASCAT pass
showed peak uncontaminated winds of 32 kt.  Given this datum, a
satellite classification of T2.5 from TAFB, and some further
increase in organization since the time of the pass, the initial
intensity estimate is increased to 35 kt.

The best estimate of Orlene's initial motion estimate is 315/11.
The cyclone should move west-northwestward to northwestward around
the southwestern periphery of a mid-level ridge over northern
Mexico today. In 24 to 48 hours, Orlene's forward motion should
decrease significantly when the cyclone encounters a weakness in
the subtropical ridge between 120W and 125W, caused by a southward
extension of a mid- to upper-level trough near the United States
West Coast.  A further reduction in forward speed and a turn toward
the north-northwest is expected by 72 hours, and Orlene could even
come to a halt in the face of weak steering around this time. There
is widespread agreement in the guidance that the subtropical ridge
will re-establish itself north of Orlene in about 4 days, which
should result in a westward or possibly a west-southwestward motion
with an increase in forward speed.  Overall, little change was made
to the previous forecast track, and the current one is close to a
consensus based on the ECMWF and GFS solutions.

East-northeasterly shear currently over Orlene is forecast to
diminish during the next couple of days while the cyclone moves
over warm waters.  Steady strengthening is expected, even though the
mid-level moisture will be only marginally favorable and SSTs will
begin to gradually lower.  If Orlene can quickly establish an inner
core, the result could be greater intensification than this
forecast predicts.  The intensity forecast becomes challenging after
48 hours since Orlene should be straddling the 26.5-deg C isotherm
for the remainder of the forecast period while the environmental
moisture becomes critically low.  There could also be some temporary
increase in southwesterly shear.  The combination of these factors
should result in a steady-state or slowly weakening cyclone from
72-120 hours.  The NHC intensity forecast is a little above the
previous one, near the multi-model consensus, but lower than the
SHIPS and FSU Superensemble output.


INIT  11/0900Z 14.8N 115.9W   35 KT  40 MPH
 12H  11/1800Z 15.8N 117.4W   45 KT  50 MPH
 24H  12/0600Z 16.8N 119.0W   55 KT  65 MPH
 36H  12/1800Z 17.6N 120.0W   65 KT  75 MPH
 48H  13/0600Z 18.2N 120.5W   75 KT  85 MPH
 72H  14/0600Z 19.1N 120.9W   75 KT  85 MPH
 96H  15/0600Z 19.1N 123.1W   70 KT  80 MPH
120H  16/0600Z 18.8N 127.2W   65 KT  75 MPH

Forecaster Kimberlain