406
FXUS65 KVEF 261753
AFDVEF

Area Forecast Discussion
National Weather Service Las Vegas NV
1053 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 18Z Forecast
Package...Thunderstorms are the main concern again this forecast
period. Storm activity should increase later today in Arizona and
southern Nevada, then track northwest. This includes the Mormon
Mesa and Peach Springs corridors. Although the most favorable time
for storms reaching the terminal is 20Z to 00Z this afternoon,
cloud cover from earlier storms may inhibit development later in
the day. 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 18Z Forecast Package...Thunderstorms will be
the main concern again this forecast period. The best chances for
storms will be south and east of the Interstate 15 corridor.
Activity is ongoing in northwestern Arizona and southern Nevada and
should move northwest through the rest of the morning and afternoon.
However, clouds left over from earlier convection may inhibit
additional storm development later today. Some storms should also
reach southeastern California during the afternoon and evening. The
main concerns with storms will be erratic gusty winds, heavy rain,
and low ceilings with terrain obscuration. Away from storms, winds
follow diurnal trends with speeds of less than 12 knots.

&&

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

&&

$$

DISCUSSION...Nickerson
AVIATION...Meltzer

For more forecast information...see us on our webpage:
https://weather.gov/lasvegas or follow us on Facebook and Twitter