812
FXUS65 KVEF 111141
AFDVEF

Area Forecast Discussion
National Weather Service Las Vegas NV
441 AM 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.

* Isolated shower and thunderstorm activity possible across various
  parts of the forecast area, with best chances in our eastern zones
  mid-to-late week.

&&

.DISCUSSION...Today through Monday.

The Desert Southwest remains sandwiched between two ridges - one
over the northeastern Pacific Ocean and one over New Mexico. Over
the next few days, the Pacific Northwest high will meander southeastward,
centering itself over our forecast area by Tuesday. As a result, expect
persistent above-normal temperatures, with afternoon readings ranging
4 to 8 degrees above seasonal normals. Extreme Heat Warnings are in
effect for Death Valley National Park, western and southern San Bernardino
County, far southern Nye County, northwestern Clark County, and southern
Mohave County at 10 AM this morning, with areas expanding to include
the Las Vegas Valley, eastern and southern Clark County, and eastern
San Bernardino County on Tuesday. Heat Advisories are in effect on
Tuesday for the Owens Valley, Esmeralda County, central Nye County,
Lincoln County, northern Mohave County, and the Clark County Mountains,
as higher elevations will provide minimal respite from valley heat.
Today and Tuesday, expect widespread Moderate Heat Risk, with increasing
coverage of Major Heat Risk (with isolated instances of Extreme) across
lower elevations. With the center of the high overhead, temperatures
are slower to cool off Wednesday onward. Will continue to assess over
the next couple of shifts, but temperatures in lower elevations may
warrant an extension of Extreme Heat Warnings into Wednesday. Troughing
approaches the Pacific Northwest late-week, which will deamplify the
aforementioned ridges and bring cooler temperatures to the region heading
into next weekend.

Another cell formed over the San Bernardino Mountains south of State
Route 62 yesterday afternoon. PWATs will retreat from southern San
Bernardino County today as the PacNW high noses into the region, so
we are not expecting anymore shower or thunderstorm activity this
afternoon. As mentioned in previous forecast discussions, modest
moisture increases across the southern Great Basin on Wednesday,
which has increased PoPs on Wednesday across our northern zones to
10 to 20%. Meanwhile, both the ECMWF and GFS ensemble means indicate
that a southerly flow mid-to-late week will bring 0.75 to 1.25 inches
of monsoonal PWAT to far southern Nevada, far southeastern California,
and northwestern Arizona. PoPs will range 30 to 50% across eastern
Mohave County Wednesday through Saturday, with between 10 and 30%
PoPs across Lincoln, Clark, and eastern San Bernardino counties. Most
likely impacts include gusty winds, frequent lightning, and isolated
instances of heavy rainfall, particularly with storms that form over
the higher terrain.
&&

.AVIATION...For Harry Reid...For the 12Z Forecast Package...Light
and variable winds early this morning start to favor a northeasterly
direction by late morning, likely lasting through the afternoon.
Southwesterly winds of less than 10 knots return after sunset. No
operationally significant clouds or weather expected at the
terminal, although wildfire smoke could reduce slantwise visibility
aloft. Temperatures meet or exceed 100 degrees between 18Z and 05Z,
peaking around 109 degrees.

For the rest of southern Nevada, northwest Arizona and southeast
California...For the 12Z Forecast Package...Expect generally
diurnal winds today. Gusty northwesterly winds arrive at KBIH in
the afternoon, and westerly to southwesterly winds pick up at KEED
and KDAG in the evening. Lofted smoke across San Bernardino
County and far southern Nevada may reduce slantwise visibility at
times.

&&

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

&&

$$

DISCUSSION...Soulat
AVIATION...Meltzer

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