028
FXUS65 KVEF 011128
AFDVEF

Area Forecast Discussion
National Weather Service Las Vegas NV
428 AM PDT Mon Sep 1 2025

.KEY MESSAGES...

* Another day of above-normal temperatures and widespread Moderate
  Heat Risk for Labor Day.

* Monsoonal moisture returns through the week, with chances of
  precipitation returning areawide and temperatures moderating
  closer to seasonal normals.

&&


.DISCUSSION...Today through Sunday.

A ridge of high pressure will continue to build over the Desert
Southwest today, making today the hottest day of the forecast
period. With height rises comes forecast afternoon temperatures 3 to
6 degrees above seasonal normals underneath mostly sunny skies.
Widespread "Moderate" Heat Risk expected today, with pockets of
"High" Heat Risk in the lower desert valleys including Death Valley,
Pahrump Valley, southern portions of the Las Vegas Valley, and the
Colorado River Valley. Those recreating outside today are encouraged
to drink plenty of water and fluids with electrolytes and to keep
outdoor activities to the cooler parts of the day.

The exception of the "mostly sunny skies" will be across the higher
elevations of southern Mohave County today, where high resolution
Convective Allowing Models (CAMs) continue to highlight the
potential for afternoon convection. Forecast HRRR soundings in
southern Mohave County show an inverted-V shape, indicating dry air
at the surface. As such, primary concerns today will be gusty winds
from the direction of storms and frequent lightning. On Tuesday, a
shortwave will push into the coast of California, which will shift
our aforementioned ridge eastward. This shift will allow additional
monsoonal moisture to usher northward into the Mojave Desert, with
over 1.00" of PWAT in Las Vegas. As the shortwave pushes inland, the
resultant instability, forcing, and moisture will increase chances
of precipitation areawide Tuesday and Wednesday. Primary hazards
will include moderate-to-heavy rainfall, isolated flash flooding,
and frequent lightning. Moisture scours out of the region northwest-
to-southeast through the rest of the work week, which will confine
precipitation chances to our eastern zones. Meanwhile, temperatures
will favor values near seasonal normals.
&&

.AVIATION...For Harry Reid...For the 12Z Forecast
Package...Light winds this morning will become east late in the
morning with speeds remaining under 8KT. Southeast winds are
expected to increase this afternoon, around 21Z. Wind speeds to
around 10KT with isolated gusts to 15KT are possible with the
southeast winds. Wind speed will decrease after sunset. VFR
conditions will persist with FEW mid-level clouds will develop over
the nearby terrain in the afternoon. There is a low chance for
isolated showers or virga in or around the terminals Tuesday early
morning around 12Z, however confidence is too low to include
precipitation in the forecast at this time. The better chance for
showers and thunderstorms with convective impacts (sudden gusty
outflow winds, CIGS to 10kft, lightning) will be Tuesday afternoon.
Temperatures will top out around 104, with temperatures exceeding
100F between 20Z and 04Z.

For the rest of southern Nevada, northwest Arizona and southeast
California...For the 12Z Forecast Package...Smoke from the Garnet
Fire on the west side of the Sierra is forecast to move into the
Owens Valley early this morning, with temporary reductions in
visibility possible. THe best chance for smoke impacts at KBIH will
be 15Z-20Z, with smoke quickly clearing when southeast winds develop
18Z-20Z. Light winds this morning will become breezy out of the
south later this afternoon, with the exception of the western Mojave
Desert where breezy east-southeastely winds will pick up in the
afternoon. Winds will diminish after sunset with typical wind
patterns setting up overnight. Isolated thunderstorms may develop
this afternoon in the terrain of western Arizona, but will quickly
diminish this evening.

&&


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

&&

$$

DISCUSSION...Soulat
AVIATION...Nickerson

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