Mountain Pass, California 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

919
FXUS65 KVEF 120504
AFDVEF

Area Forecast Discussion
National Weather Service Las Vegas NV
1004 PM PDT Mon Aug 11 2025

.KEY MESSAGES...

* Above-normal temperatures continue through the first half of the
  week, with Extreme Heat Warnings and Heat Advisories in effect.
  Temperatures will cool but remain at or slightly above normal the
  second half of the week.

* Showers and thunderstorms chances increase the second half of the
  week, with best chance in eastern zones mid-to-late week. Heavy
  rain with isolated flash flooding would be possible with any
  convection in these eastern areas.

* Dry lightning could also increase fire danger the second half of
  the week, especially in western areas if any convection is able to
  develop in the drier air.

&&

.DISCUSSION...Through Monday.

Temperatures will climb 5-8 degrees above normal today and Tuesday
as high pressure builds east over the region. Major Heat Risk is
expected today in Death Valley National Park, western and southern
San Bernardino County, far southern Nye County, northwestern Clark
County, and southern Mohave County where an Extreme Heat Warning is
now in effect. Temperatures will peak on Tuesday as Major Heat Risk
expands into many desert valley areas, and as such additional
Extreme Heat Warnings go into effect for the rest of the desert
areas including the Las Vegas Valley. Further north, Heat Advisories
are in effect on Tuesday through the Southern Great Basin, the Owens
Valley, and northern Mohave County where widespread Moderate Heat
Risk in populated areas and some Major Heat Risk in rural locations
is expected. In addition, a Heat Advisory is in effect on Tuesday in
the Spring Mountains and Sheep Range where high temperatures will be
well above normal and little relief from the valley heat is
expected. As the area of high pressure continues to shift east and
breaks down the second half of the week, temperatures will cool.
Wednesday`s temperatures will still be above normal and only cool a
degree or two compared to Tuesday. Lingering Major Heat risk is
still showing up in some valley locations of far southern Nevada and
Death Valley which may require the extension of heat products into
Wednesday. Will continue to monitor trends to see if this slower
cooling trend expands into additional areas. Thursday onward will be
cooler, and by this weekend high temperatures may fall about 3-5
degrees below normal.

The high will break down and be replaces by a broad West Coast
trough Wednesday through the weekend. Modest moisture increases are
expected as the trough moves in, especially in southern Nevada and
western Arizona where PWATs will climb to 0.75 to 1.25 inches. With
modest moisture and decent upper level support, afternoon showers
and thunderstorms are possible Wednesday through Saturday. While
moisture will remain unremarkable, the forcing set up should be
enough for organized convection at times. Ensemble meteograms also
show an increase in instability, which would also support
convection. WPC has highlighted parts of Mohave County with a
marginal risk for excessive rainfall leading to isolated flash
flooding, which is a reasonable assessment given the synoptic set up
and western Arizona is where the highest moisture should be
situated. Additional thunderstorms impacts are possible, including
sudden gusty winds and lightning as well as heavy rain in areas west
of Mohave County, but confidence in these impacts are lower at this
time.

Further west in San Bernardino, Inyo, and western parts of the
Southern Great Basin, dry air will remain in place which will limit
shower and thunderstorm chances. However, with the trough sitting
over the area, the potential for elevated convection is not zero.
Afternoon relative humidities will drop below 15% each day but
current wind speeds look marginal for reaching traditional Red Flag
Warning criteria, but if any thunderstorms are able to develop
Thursday and Friday outside of Mohave County, dry lighting could
pose a risk.

&&

.AVIATION...For Harry Reid...For the 06Z Forecast Package...Winds
remain light and follow typical daily patterns for most of the
period. However, mid to late Tuesday afternoon, winds are expected
to turn southeasterly and may approach 10 knots at times (30%
chance). Mostly clear skies with a few mid-level and high clouds.
Temperatures to exceed 100F between 18z and 05z, with a peak around
111F.

For the rest of southern Nevada, northwest Arizona and southeast
California...For the 06Z Forecast Package...Light breezes across
much of the region tonight and Tuesday, with winds generally
following typical daily patterns. The exception to this is the KDAG
area where winds remain westerly, becoming gusty during the evening
and early nighttime hours. A few mid-level and high clouds around,
but greater cloud coverage expected near KBIH due to weak afternoon
convection on the Sierra and White Mountains. Precipitation not
likely in the Owens Valley floor (less than 10%), but cannot rule
out some gusty outflow winds.

&&

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

&&

$$

DISCUSSION...Nickerson
AVIATION...Woods


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