Flash Flood Warning 51, NWS Las Vegas, NV

Area Forecast Discussion
National Weather Service Las Vegas NV
545 PM PDT Mon Aug 25 2025

.KEY MESSAGES...

* Widespread showers and thunderstorms continue through Monday
  night, with best chances of flash flooding beneath training storms
  or storms anchored to high terrain as well as for far southern San
  Bernardino County. Showers and thunderstorms are most likely on
  Tuesday with decreasing chances through the rest of the week.

* Temperatures will be much cooler on Tuesday than in it has been
  lately. However temperatures will rebound and approach seasonal
  norms by the weekend.

.DISCUSSION...Today through Monday

Thunderstorm activity has been focused mainly along the higher
terrain from northeast Clark county through Lincoln County and along
the Sierra Crest this afternoon. A cloud shield associated with
decaying nocturnal storms last night has limited convection across
most of Clark and Mohave Counties thus far today. Clearing is
southern San Bernardino is providing an opening for strong
thunderstorms in the Morongo Basin and will serve a the focus for
strong storms throughout the evening hours. Sufficient precipitable
water and thermodynamics isolate this area for the potential for
rain rates of 1-2 inches per hour this evening. The chance for
stormy weather continues with an overnight cluster of storms over
Clark and Mohave counties bringing a potential mess for rush hour
Tuesday morning in Las Vegas.

All of this is due to a continued influx of monsoon moisture
compliments of our four corners high, complimented by onshore flow
due to a shortwave trough off the California coast. This southwest
flow is bringing drier air into the area. While this drying reduces
available moisture, it also provides dynamic forcing, creating an
environment where storms can form more easily without the need for
orographic lift. While Tuesday will be the most convectively active
day this week, thunderstorms are possible each day through the
weekend with decreasing chances each day and storms becoming more
and more terrain-driven.

With the influence of the shortwave trough, temperatures will be
cooler across the region on Tuesday. High temperatures will be
around ten degrees below normal Tuesday, although that could vary
widely depending on cloud cover and associated thunderstorm
activity. With fewer clouds and drier air on Wednesday, a warming
trend ensues. Temperatures will rebound slowly approaching
climatologic normal by the weekend.

&&

.AVIATION...For Harry Reid...For the 00Z Forecast Package...It looks
like thunderstorms have ended for the remainder of the evening with
just a few showers possible over the surrounding mountains. Winds
will be a little tricky this evening with northwest to north winds
generally around 10 knots or less; however, some gusts to around 15
knots are possible through 03z. There is also the possibility of
storms developing late tonight, closer to sunrise and gone ahead and
reintroduced VCTS into the TAF, although confidence does remain low
at this time. If this occurs, we will need to watch for the threat
of gusty outflow winds. The greater threat of showers and
thunderstorms will be after 19z with gusty outflow winds and CIGs
down to around 8k feet. Temperatures are not expected to reach 100F
on Tuesday.

For the rest of southern Nevada, northwestern Arizona and
southeastern California...For the 00Z Forecast Package...Showers and
thunderstorms will be more widespread this evening across Inyo and
western San Bernardino counties, impacting the KDAG and KBIH TAF
sites. Gusty and variable outflow winds will be possible through the
evening hours. Elsewhere a few showers are possible, mainly over the
higher terrain overnight, but little impacts to the other TAF sites.
Outside of any thunderstorm influences, look for winds to generally
remain less than 10 knots along with CIGs AOA 12k feet. Scattered
thunderstorms are again expected Tuesday and could potentially
impact all TAF sites. Gusty outflow winds will remain a concern
through the day.

&&

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

&&

DISCUSSION...Berc
AVIATION...Gorelow

For more forecast information...see us on our webpage:
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Preliminary Local Storm Report
National Weather Service Las Vegas NV
418 PM PDT Mon Aug 25 2025

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0347 PM     Flash Flood      2 E Joshua Tree         34.14N 116.28W
08/25/2025                   San Bernardino     CA   Trained Spotter

            CA-62 flooded at White Feather Road.

0347 PM     Tstm Wnd Gst     2 WSW Twentynine Palms  34.13N 116.08W
08/25/2025  M68 MPH          San Bernardino     CA   Trained Spotter

            Trained weather spotter reported a wind gust
            to 68 mph.

0410 PM     Flash Flood      Twentynine Palms        34.14N 116.05W
08/25/2025                   San Bernardino     CA   Law Enforcement

            CA 62 flooded at Adobe Rd in Twentynine
            Palms.

&&

Preliminary Local Storm Report
National Weather Service Las Vegas NV
425 PM PDT Mon Aug 25 2025

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0405 PM     Flash Flood      3 W Twentynine Palms    34.14N 116.10W
08/25/2025                   San Bernardino     CA   Broadcast Media

            CA-62 flooded at Encelia Dr. Multiple
            vehicles trapped in fast moving water.

&&

BEP

Preliminary Local Storm Report
National Weather Service Las Vegas NV
635 PM PDT Mon Aug 25 2025

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0620 PM     Flash Flood      6 SSW Trona             35.68N 117.39W
08/25/2025                   San Bernardino     CA   Law Enforcement

            CHP reports Flash Flood along SR-178 near
            Pinnacle Road.

&&

BEP