Severe Thunderstorm Warning 42, NWS Las Vegas, NV

Area Forecast Discussion
National Weather Service Las Vegas NV
117 PM PDT Sat Aug 23 2025

.KEY MESSAGES...

* The Extreme Heat Warnings and Heat Advisories will continue
  through this evening with temperatures cooling as we head into
  next week.

* Showers and thunderstorms capable of producing strong outflow
  winds and flash flooding will be possible this afternoon, with the
  highest risk for thunderstorms and impacts in Inyo County through
  the Southern Great Basin.

* Another round of showers and thunderstorms are possible Sunday
  afternoon, but low confidence in where the highest chances for
  precipitation and impacts will exist.

* Chances for showers and thunderstorms will continue into next week
  before drying out the end of the work week.

&&

.DISCUSSION...

The Extreme Heat Warnings and Heat Advisories look good to remain
in effect through later this evening as tonight's overnight low's
will be cooler than last night and Sunday will be cooler than the
past few days. Temperatures will continue to cool as we head into
next week, dropping below normal beginning Monday and Tuesday.
Once they return, these cooler than normal temperatures will
continue through the end of the week.

Through the morning hours, satellite imagery shows mostly sunny
skies through the Western Mojave Desert into Inyo and Esmeralda
counties, which has allowed for some destabilization. Showers and
thunderstorms have started to initiate. This area should be the
focus for thunderstorms and impacts this afternoon, with the highest
chances in the Sierra and Owens Valley as a weak disturbances moves
north through the mean upper level flow. Further east in Mohave
County and much of Southern Nevada, scattered showers and abundant
cloud cover persisted through the morning in response to a decaying
MCV moving into Lincoln County. With widespread clouds cover,
instability has been limited which is hindered thunderstorm
development. Much like yesterday, these clouds and ongoing activity
in Southern Nevada and Mohave County will limit afternoon
thunderstorm development. If clouds are able to clear some in this
area, showers and thunderstorms could develop late this afternoon
and evening, which some hi-res models do show. Strong outflow winds,
moderate-to-heavy rain, flash flooding, and frequent lightning will
be possible with any storms that develop this afternoon. If
thunderstorms can develop in Mohave County later today, outflow
winds from distant storms will have the potential to impact area
lakes, resulting in choppy waves and hazardous boating conditions.

After precipitation wanes tonight, chances for showers and
thunderstorms return Sunday afternoon. With no obvious synoptic
forcing, Sunday's convection will favor the terrain then rely
heavily on mesoscale features that develops from each day's overall
storm activity. The highest chances for thunderstorms Sunday will
again be in Inyo County through the Southern Great Basin where the
least amount of morning cloud cover is currently expected, however
that could change as this afternoon unfolds and lays the groundwork
for tomorrow's overall setup. PWATs of 0.75-1.50 inch will be in
place across the region which would bring a risk for heavy rain and
flash flooding (especially where training or slow moving storms
develop). In addition to heavy rain- strong gusty winds and
lightning are possible with any thunderstorms Sunday.

Storm chances continue into next week as moisture lingers across the
region. Monday should be largely like the past few days where the
highest risk for thunderstorms will depend on how the previous day
unfolded. Hazards will remain the same the first half of next week
with strong outflow winds, heavy rain, flash flooding, and frequent
lightning possible with any storms that develop. With a shortwave
potentially moving through the region Tuesday and/or Wednesday, more
widespread and/or higher impact precipitation is possible if
moisture and forcing are able to overlap. Ensembles show a variety
of solutions with the incoming shortwave and how precipitation will
develop, thus there remains a lot of uncertain with next week's
forecast. Will continue to monitor precipitation chances and
potential impacts next week. After Wednesday, models show drier air
filtering into the region as the flow turns southwest, which should
end our active pattern the second half of next week.

&&

.AVIATION...For Harry Reid...For the 18Z Forecast Package...Lots of
debris clouds continue to pass through the area this morning, which
will inhibit heating and likely delay the threat of thunderstorms
through early afternoon. Storms could still develop over the
mountains early this afternoon, but the better chances for anything
to affect the terminal should hold off until late afternoon (if it
occurs at all). The main concern with any nearby storms will be
erratic gusty winds, with a lower (but not zero) chance of brief
heavy rain and lower ceilings. A few light showers could persist
into the night. Storms are expected to develop on the mountains
again around midday Sunday. Much lower confidence in the temperature
forecast due to the cloud cover. The best chances for exceeding 100F
will come between 18Z and 04Z.

For the rest of southern Nevada, northwest Arizona and southeast
California...For the 18Z Forecast Package...Main area of convection
this morning remains over western Inyo County along the 395 corridor
and along the Sierra Crest. Storms this morning have been increasing
in coverage and it's likely that development will continue through
the afternoon. Some heavy rain, gusty outflow winds, and frequent
lightning will be a concern. Other areas of Inyo County will also
see areas of scattered thunderstorms through the afternoon. For the
remainder of the area, still seeing some debris clouds over the area
which will inhibit development for a little while, but by the
afternoon we should see areas of isolated to scattered thunderstorms
over most areas. The main threats with storms will be erratic gusty
winds, locally heavy rain, and low ceilings with terrain
obscuration. The threat of afternoon showers and thunderstorms will
continue across the region each day through at least Tuesday.
However, Tuesday and Wednesday have been consistently showing the
potential to be the most impactful days of next week in terms of
weather.

&&

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

&&

DISCUSSION...
AVIATION...Gorelow

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