816
FXUS65 KVEF 011730
AFDVEF

Area Forecast Discussion
National Weather Service Las Vegas NV
1029 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 18Z Forecast Package...Light
northeast winds will continue into the early afternoon before
turning to the southeast by 21Z.  Sustained speeds should remain
less than 10 knots, although a few gusts to 15 knots will be
possible.  Speeds will decrease around sunset, and directions should
settle into their typical southwest downslope pattern.  Similar wind
patterns are expected on Tuesday.  VFR conditions will prevail into
tonight.  Model guidance continues to show an area of weak
showers/virga moving across the valley around sunrise, followed by a
better chance of scattered thunderstorms tomorrow afternoon and
evening.  The best chance of convective impacts at the terminal will
be after 21Z, when gusty outflow winds to 30 knots, lightning, and
CIGs down to 10kft AGL will be possible.   Temperatures will top out
around 104F today with readings exceeding 100F between 20Z and 04Z.

For the rest of southern Nevada, northwest Arizona and southeast
California...For the 18Z Forecast Package...Smoke from wildfires
burning on the west side of the Sierra has begun to move into the
Owens Valley late this morning.  Visibility has remained 7SM or
greater at KBIH, although brief periods of lower visibility will be
possible through early afternoon.  Once the southeast winds develop
around 20Z, improving conditions are expected.  Elsewhere, generally
good conditions are expected today with winds remaining less than 12
knots.   An isolated thunderstorm is possible over the higher
terrain of northwest Arizona this afternoon, but all other areas are
expected to remain dry.  Scattered thunderstorms are expected to
develop across much of the region tomorrow afternoon as monsoonal
moisture returns to the area.

&&


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

&&

$$

DISCUSSION...Soulat
AVIATION...Planz

For more forecast information...see us on our webpage:
https://weather.gov/lasvegas or follow us on Facebook and Twitter