High Wind in Nevada, November 1, 2022

Area Forecast Discussion
National Weather Service Las Vegas NV
933 PM PDT Tue Nov 1 2022

.SYNOPSIS...
A potent upper trough is digging into the western U.S. As it does
so, several compact waves embedded in the larger flow will impact
the southwest U.S. through mid to late week. This will result in
periods of windy/breezy conditions, much colder air, and the first
snow of the season.
&&

.UPDATE...Winds have begun to subside this evening, with the
majority of the Wind Advisory allowed to expire on time. Persistent
southwest winds on and downslope of the Spring Mountains will remain
elevated overnight, with the Wind Advisory for that zone continuing
through 6 AM PDT. As a cold, digging area of low pressure continues
to move southward through the Great Basin, precipitation chances
will increase in the higher terrain of the southern Great Basin. An
additional band of moisture will smack the Sierra Nevada, with spill
over into the Owens Valley possible tonight. Precipitation chances
will continue to move southeasterly through the Desert Southwest
through the day Wednesday into Thursday morning. Northwestern
Lincoln and northern Mohave counties will be the hot spots for QPF
for this system. Light snowfall accumulations cannot be ruled out as
far south as Mountain Pass and the Spring Mountains as the trough
axis pushes through our forecast area and drops snow levels below
4000 feet. Light rain possible in Las Vegas Thursday morning. No
changes have been made to the forecast this evening, as it looks to
be in good shape.
&&

.PREVIOUS DISCUSSION...244 PM PDT Tue Nov 1 2022/

.SHORT TERM...Through Friday...
A powerful storm system is already making its presence known this
afternoon as southerly winds continue to increase in response to
its approach. Winds of 25 to 35 mph with gusts of 40 to 50 mph
still appear to be a good bet, with locally higher gusts expected
primarily over the higher elevations. Recent Hi-res ensembles and
the European Extreme Forecast Index continue to point to an
unusually windy period for the remainder of today through tomorrow
morning. A couple of areas of potential concern for stronger
winds remain the 395 corridor from roughly Lone Pine to Wilkerson,
and the foothills of the Spring Mountains. In these areas,
downslope winds may lead reach lower elevations with wind gusts of
60 mph or more. However, these are not expected to be prevalent
and the ongoing wind advisory appears to be in good shape. In
addition to the winds, areas of blowing dust may lead to reduced
visibilities, particularly near dry lake beds where soils are
easily lofted. Winds will persist overnight and gradually decrease
on Wednesday. However, breezy conditions look to continue into
late week as we remain unsettled.

In addition to the wind, a surging front will bring much colder
air into the region. While many areas are in the mid 60s to lower
80s today, temperatures are set to fall some 15-20 degrees by
this time tomorrow. This will lead to falling snow levels and the
potential for higher elevation snow mid to late week. Initially, a
wave of light precipitation looks to affect mainly the mountains
and portions of Lincoln County tonight into early Wednesday. As a
secondary wave develops and brings additional moisture into the
region, expect additional mountain snow and valley rain to develop
late Wednesday into Thursday. All told, some higher elevation
locations of southern Nevada, southeast California, and western
Arizona look to pick up accumulating snow. Confidence at this time
is highest in impactful snowfall across Lincoln county and points
northeast into Utah. This is where ensemble probabilities are
highest for snowfall totals in excess of 3-5 inches. A Winter
Weather Advisory has been issued to account for this, mainly above
5000 feet. Some ensemble members depict a low chance (10-20%) of
some light snow at lower elevations early Thursday, but given warm
ground temperatures, the potential for accumulating snow remains
very low. Thursday also looks to be quite chilly with breezy
conditions persisting and highs only climbing to the 50s and low 60s
most lower elevations and 30s/40s in higher elevations.

With colder air spilling into the region and light winds finally
taking hold, expect additional freeze potential for some areas
Thursday night into Friday morning.

.LONG TERM...Friday Night through Monday...
Heading into the weekend, a gradual warming trend is expected as
ensembles point to a building ridge of high pressure. This looks
to be rather short lived, however, as longer range ensemble
guidance points to broad troughing across the western U.S.
Deterministic solutions reveal the potential for several upper
troughs heading into early next week. this may result in a return
of mainly mountain precipitation and breezy conditions. However,
confidence remains low on timing and or the intensity of any
potential weather maker.
&&

.AVIATION...For Harry Reid...Winds should favor a 150-180 direction
with gusts around 20 knots before increasing and becoming
primarily out of the south-southwest with gusts 30-35 knots.
Speeds should slowly trend downward overnight but remain gusty
from 20-25 knots. Gusty conditions persist into tomorrow, although
winds are expected to be a little weaker. SCT-BKN clouds will
stick around through the TAF period, with bases AOA 12 kft.

For the rest of southern Nevada, northwest Arizona and southeast
California...Gusty south-southwest winds begin in the late morning
across the area, and are expected to persist through the TAF
period at most sites. Sustained winds in the Las Vegas Valley at
15-20 knots, with gusts of 30-35 knots. At KBIH, some degree of
downsloping is anticipated this afternoon, shifting the wind
direction more west-southwesterly. Hi-res models show potential
for rotor development in the Owens Valley, which would produce
very turbulent and variable wind conditions. Light precipitation
will also be possible at KBIH in the evening hours as showers try
to spill over the Sierra. This may cause CIGs to drop as low as 6
kft, but confidence in any spillover precipitation is low. Breezes
turn northerly overnight. For KDAG, southwest winds of 20-25
knots and gusts around 35 knots this afternoon and evening. For
sites in the Colorado River Valley, southerly winds gusts around
30-35 knots, with speeds falling off in the late evening and
overnight. SCT-BKN clouds AOA 12 kft expected across the region,
except the aforementioned caveats at KBIH.
&&

.SPOTTER INFORMATION STATEMENT...Spotters are encouraged to report
any significant weather or impacts according to standard operating
procedures.
&&

UPDATE...Varian
DISCUSSION...Austin
AVIATION...Salmen

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