004
FXUS65 KVEF 211136
AFDVEF

Area Forecast Discussion
National Weather Service Las Vegas NV
436 AM PDT Thu Aug 21 2025

.KEY MESSAGES...

* Extreme Heat Warnings and Heat Advisories will continue through
  Saturday as hotter than normal temperatures stick around through
  the end of the week.

* Monsoonal moisture returns to the region, bringing increased
  chances for afternoon showers and thunderstorms as we head into
  the weekend and next week. Lightning, strong outflow winds, and
  heavy rain capable of resulting flash flooding will be possible.

&&

.DISCUSSION...through next Thursday.

Hotter than normal temperatures will continue through Saturday as
the Four Corners High remains the dominant synoptic feature across
the Desert Southwest. Widespread Major HeatRisk (Level 3 of 4) with
pockets of Extreme HeatRisk (Level 4 of 4) are expected today and
tomorrow. These high HeatRisk levels are being driven by the
combination of hotter than normal afternoon high temperatures and
much warmer than normal overnight low temperatures. High
temperatures on Saturday will cool slightly relative to Friday.
However, overnight low temperatures will be around 7 to 14 degrees
above normal, which will keep HeatRisk elevated on Saturday.
Temperatures will return to normal on Sunday and will drop below
normal as we head into next week.

Moisture will continue to push into the northwestern Arizona,
southern Nevada, and southeastern California through early next week
as southeasterly monsoonal flow persists. Isolated showers and
thunderstorms will be possible in Lincoln and Mohave Counties this
afternoon with chances becoming more widespread Friday into the
weekend as moisture continues to increase. Frequent and dangerous
lightning, strong outflow winds, and moderate-to-heavy rain capable
of resulting in flash flooding will be threats with any storms that
develop over the next few days. One potential point of failure when
it comes to storms this weekend will be lingering cloud cover
limiting daytime heating and decreasing the instability necessary
for storms to develop. Precipitation chances will continue into next
week. However, chances for precipitation are higher than would be
expected given that there is no clear forcing mechanism to help
initiate convection.

&&

.AVIATION...For Harry Reid...For the 12Z Forecast
Package...Winds today will once again follow diurnal patterns,
shifting to the east-northeast by late morning, then continue
veering to the southwest through the afternoon. Wind speeds are
expected to remain under 10KT, with VFR conditions prevailing.
Periodic mid and high clouds will continue streaming across the
region, though are expected to remain around 12kft or above.
Temperatures today will exceed 100F between 18Z-06Z, with a high
of 110F expected around 00Z.


For the rest of southern Nevada, northwest Arizona and southeast
California...For the 12Z Forecast Package...Similar to previous
days, winds across the region will generally follow diurnal
patterns, with speeds remaining around 10KT or less. An exception
will be in the Owens Valley this afternoon, where gusty up-valley
winds to 15-20KT are expected. Mid and high clouds will continue
streaming over the region through the forecast period, but VFR
conditions will prevail. Isolated thunderstorms are expected this
afternoon, mainly over portions of Lincoln and Mohave Counties,
and are not expected to impact area terminals.

&&

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

&&

$$

DISCUSSION...Stessman
AVIATION...Phillipson

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