000
WTPZ44 KNHC 312032
TCDEP4

Tropical Storm Lidia Discussion Number   9
NWS National Hurricane Center Miami FL       EP142017
300 PM MDT Thu Aug 31 2017

Satellite imagery indicates that Lidia continues to become better
organized, with convective bands now wrapping most of the way
around a ragged clear-air center.  Recent surface observations from
the Cabo San Lucas area support increasing the initial intensity to
55 kt, although it is unclear how much terrain enhancement of these
winds is occurring.

The initial motion is north-northwestward or 335/7 kt between a
mid-level anticyclone centered over central Mexico and a mid- to
upper-level low located to the west over the Pacific.  This motion
should continue for the next 24 h or so.  After that time, a
mid-level anticyclone over the southwestern United States should
become the main steering influence from 48-120 h, forcing Lidia to
turn northwestward and eventually westward.  The guidance has become
somewhat less tightly spread, as the GFS is currently a right
outlier showing a motion into the northern Gulf of California.
Given the lack of support for this scenario from the other models,
the new forecast track is similar to the previous track and a little
south of the consensus models

Additional strengthening is possible this evening before the center
moves over the Baja California peninsula, and while the chance
of Lidia becoming a hurricane is low it is still non-zero.
Weakening is expected after 12 h due to the center moving up the
spine of the Baja California peninsula, but tropical-storm-force
winds are likely to spread up the Gulf of California well east of
the center.  Lidia is forecast to become a remnant low by 72 h
due to interaction with land and cold water, and further weakening
is anticipated over the cold waters west of the northern Baja
California peninsula at 96 and 102 h.

Lidia is a large system accompanied by very heavy rains which are
already occurring over portions of western Mexico and Baja
California Sur.  Regardless of how strong Lidia becomes,
life-threatening flash floods and mudslides will be a significant
hazard over these areas.  In addition, the mountainous terrain of
the Baja California peninsula could enhance the winds at higher
elevations.


FORECAST POSITIONS AND MAX WINDS

INIT  31/2100Z 22.7N 110.1W   55 KT  65 MPH
 12H  01/0600Z 23.8N 110.7W   60 KT  70 MPH
 24H  01/1800Z 25.2N 111.7W   50 KT  60 MPH...INLAND
 36H  02/0600Z 26.8N 113.0W   45 KT  50 MPH...INLAND
 48H  02/1800Z 28.2N 114.4W   40 KT  45 MPH...OVER WATER
 72H  03/1800Z 30.0N 117.0W   30 KT  35 MPH...POST-TROP/REMNT LOW
 96H  04/1800Z 30.5N 120.0W   20 KT  25 MPH...POST-TROP/REMNT LOW
120H  05/1800Z 30.5N 123.0W   15 KT  15 MPH...POST-TROP/REMNT LOW

$$
Forecaster Beven