ZCZC MIATCDEP4 ALL
TTAA00 KNHC DDHHMM

Tropical Storm Lidia Discussion Number  13
NWS National Hurricane Center Miami FL       EP142017
300 PM MDT Fri Sep 01 2017

The center of Lidia has been moving over the southern portion of
the Baja California peninsula.  While the convective cloud pattern
has become somewhat ragged, a recent surface observation from
Loreto, Mexico indicates that maximum sustained winds remain near
50 kt.  The storm also continues to have a large wind field in the
eastern semicircle as shown by a prolonged period of tropical-
storm-force winds at Los Mochis on the Mexican mainland.

Weakening is expected while the circulation interacts with the
mountainous terrain of Baja California.  However, tropical-storm-
force winds will continue to extend well east of the center, riding
up the peninsula and adjacent Gulf of California for about the
next 24 hours.  When Lidia emerges over the Pacific, it is expected
to be over sea surface temperatures near or below 24C, which should
cause it to quickly decay to a remnant low.  The latest large-scale
model guidance suggests that a circulation should persist through
96 h, possibly due to interaction with a nearby mid- to upper-level
low late in the forecast period.  Thus, a 96 h point has been
included.

The initial motion is now 325/10.  Lidia remains between a mid-level
high centered over the southwestern United States and the
aforementioned mid- to upper-level trough to the southwest and south
over the Pacific, and these features should keep the cyclone on a
general northwestward course for the next 72 h or so, followed by a
turn toward the west-northwest.  The new forecast track has the
center over or just off of the west coast of the Baja California
peninsula for the next 18-24 h before emerging over the Pacific
Ocean. Overall the new track is an update of the previous track that
lies close to, but is slightly faster than, the various consensus
models.

While Lidia should weaken, the heavy rainfall threat will continue
over northwestern Mexico and the Baja California peninsula during
the next few days.  Moisture from the cyclone could reach the
southwestern United States over the weekend.


FORECAST POSITIONS AND MAX WINDS

INIT  01/2100Z 25.5N 111.9W   50 KT  60 MPH...INLAND
 12H  02/0600Z 26.8N 113.0W   45 KT  50 MPH...INLAND
 24H  02/1800Z 28.2N 114.6W   35 KT  40 MPH...OVER WATER
 36H  03/0600Z 29.4N 116.4W   30 KT  35 MPH...POST-TROP/REMNT LOW
 48H  03/1800Z 30.7N 118.3W   25 KT  30 MPH...POST-TROP/REMNT LOW
 72H  04/1800Z 33.0N 123.0W   20 KT  25 MPH...POST-TROP/REMNT LOW
 96H  05/1800Z 34.0N 127.0W   20 KT  25 MPH...POST-TROP/REMNT LOW
120H  06/1800Z...DISSIPATED

$$
Forecaster Beven

NNNN