Severe Thunderstorm Warning 60, NWS Las Vegas, NV

Area Forecast Discussion
National Weather Service Las Vegas NV
436 AM PDT Fri Sep 26 2025

.KEY MESSAGES...

* Chances of showers and thunderstorms in the forecast for southern
  Nevada, southeastern California, and northwestern Arizona through
  the weekend.

* Moisture gradually scours out of the region through the work
  week, with a fall-like pattern bringing below-normal
  temperatures and breezy afternoons.
&&

.DISCUSSION...

A cut off low sitting over south-central California will continue to
shift inland today, allowing for showers and thunderstorms to
develop ahead of low as it does so. While areas along and south of
the I-15 could see showers and thunderstorms today and Saturday,
today's thunderstorm chances and areas of focus will be highly
dependent upon how much activity there is this morning. Some hi-res
model runs show an area of thunderstorms developing in western
Mohave and/or eastern Clark County after sunrise, pushing east
through the morning. If this occurs, it would limit afternoon
thunderstorms in the afternoon. If this morning remains less
activity, this afternoon would have higher chances. Based on current
satellite imagery showing scattered clouds already developing in
eastern Clark County, favored the earlier solution. Better moisture
will advect into the region as the flow becomes more southerly when
the low pivots into the Lower Colorado River Valley this afternoon
and Saturday- which will increase the threat of heavy rain. Isolated
flash flooding will be possible, especially with any training
storms, with Saturday being the highest threat for flash flooding as
PWATs peak at 0.75-1.5 inches across the region. In addition,
thunderstorms today and Saturday could produce sudden gusty winds,
small hail, and lightning.

The upper level low tracks east into Arizona and weaken on Sunday.
There will continue to be a chance for showers and thunderstorms
across much of the area on Sunday as some moisture will remain,
though how much moisture lingers is a bit uncertain. After Sunday,
The closed low will weaken into an open wave by early next week as
it pushes through Arizona and New Mexico. The resultant flow will be
southwesterly, which is typically a dry pattern for our forecast
area; however, remnants of what is now Hurricane Narda will get
swept up into the flow, returning chances of terrain-based
convection Monday and Tuesday afternoons. By midweek, a fall-like
trough will approach the Desert Southwest, bringing breezy and dry
conditions. Details of next week's forecast will become more clear
as we move through the weekend.

&&

.AVIATION...For Harry Reid...For the 12Z Forecast Package...Thunderstorms will be the main concern again for this
period. Storms at or near the terminal are expected later this
morning into the afternoon. Storms are expected to develop over Lake
Mead shortly after sunrise and move west-northwesterly towards the
valley. Afternoon storm chances will be dependent on how this
morning plays out as lingering cloud cover may inhibit additional
storm development this afternoon. The primary threats with any
storms that develop will be rain, lower CIGS, lightning, and
variable gusty outflow winds. Outside of any convective influence,
winds will remain relatively light, 10 knots or less, and will
follow typical diurnal directional trends.

For the rest of southern Nevada, northwest Arizona and southeast
California...For the 12Z Forecast Package...Thunderstorms will be
the main concern again for today. The best chances for storms
will be south and east of the Interstate 15 corridor with storms
developing in the Lake Mead area shortly after sunrise and moving
west-northwest into southern Nevada during the morning. Storms
will eventually push into southeastern California during the
afternoon. There is a lesser, but non-zero, chance that may also
develop in the higher terrain of Inyo County and the southern
Great Basin this afternoon. The main threats with storms will be
erratic gusty winds, heavy rain, and low ceilings with terrain
obscuration. Away from storms, winds should around 12 knots or
less.

&&

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

&&

DISCUSSION...Nickerson
AVIATION...Stessman

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