261
FXUS65 KVEF 030947
AFDVEF

Area Forecast Discussion
National Weather Service Las Vegas NV
247 AM PDT Wed Sep 3 2025

.KEY MESSAGES...

* Monsoonal moisture remains in place today before slowly
  retreating eastward out of the region, shifting the best
  precipitation chances further east each day.

&&


.DISCUSSION...Today through Tuesday.

Monsoonal moisture will surge farther north into the southern Great
Basin today. Meanwhile, a vorticity lobe will stretch along the
California-Nevada state line today, providing ample forcing aloft to
sustain widespread showers and thunderstorms again this afternoon.
Yesterday, morning convection overachieved, and resulted in thick
cloud cover through the morning and early-afternoon, which
resulted in a more stable environment than expected, thus fewer
thunderstorms than forecast. Today, clearing will slowly occur
through the morning, eventually exposing our southern zones to
sunlight. The resultant daytime heating will allow CAPE values to
increase to 500- 1000 J/kg across eastern San Bernardino County,
southern Clark County, southern Mohave County, and the Colorado
River Valley. Despite ample mid-and-upper level moisture, forecast
HRRR soundings continue to show dry air at the surface across our
southern zones, so gusts between 35 and 45 mph cannot be ruled
out with stronger thunderstorms. Additional threats include
frequent lightning, locally heavy rainfall, and isolated instances
of flash flooding this afternoon. Though forcing aloft is best in
the southwestern Great Basin - primarily across Esmeralda County
- morning cloud cover will keep that area relatively stable
through the day. We still expect moisture to gradually retreat
southeastward from our forecast area through the remainder of the
week and into the weekend; however, the speed at which the
moisture retreats has been delayed somewhat due to Hurricane
Lorena approaching Baja California. Daytime heating and remnant
forcing aloft coupled with this moisture return PoPs to our
eastern zones each day heading into the weekend. &&


.AVIATION...For Harry Reid...For the 06Z Forecast Package...Clouds
and isolated, vicinity showers linger through the night. Cloud bases
should stay above 10kft. Light northerly or variable winds continue
through the night, turning more easterly mid/late morning. By
afternoon, vicinity storms are expected to develop on the high
terrain as long as skies clear sufficiently beforehand. If cloudy
conditions persist through the morning, any convection will likely
be delayed. Currently, best chances for storms/outflow to reach the
terminal are in the late afternoon and early evening hours. By late
evening, it looks like convective activity will begin to wane.

For the rest of southern Nevada, northwest Arizona and southeast
California...For the 06Z Forecast Package...Widespread clouds and
scattered showers linger through the night. Cloud bases should
remain at or above 10kft across the area. Scattered showers and
storms are expected to develop again Wednesday afternoon, favoring
southern Nevada, northwestern Arizona, and the Sierra crest. Main
concerns will be gusty outflow winds near any convection. The extent
of morning cloud cover and precipitation will influence the coverage
and intensity of convection in the afternoon. By late evening,
storms should begin to wane and become more isolated in nature.
Outside of any convective influences, winds will be fairly light.
&&


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

$$

DISCUSSION...Soulat
AVIATION...Woods

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NWS Flagstaff Office