448
FXUS65 KVEF 172326
AFDVEF

Area Forecast Discussion
National Weather Service Las Vegas NV
425 PM PDT Mon Aug 17 2026

.KEY MESSAGES...

* Temperatures will peak on Wednesday and Thursday, with above-
  normal afternoon highs and near-record morning lows.

* Monsoon moisture increases late this week into the weekend,
  accompanied by increased shower and thunderstorm chances.

&&

.DISCUSSION...Through next weekend.

Broad ridging continues building westward across the Desert
Southwest today, with increasing thicknesses and subsidence
lending to our current warming and drying trend. Most locations
will stay dry this afternoon, though there is around a 10 percent
chance for isolated showers to develop across the southern Great
Basin and northwestern Arizona, with gusty winds and an
occasional lightning strike the primary concerns. The building heat
will be the focus through late in the work week, with
temperatures continuing to climb to around 5 to 7 degrees above
normal Wednesday and Thursday. Lingering low-level moisture will
serve to temper afternoon highs somewhat, however, this same
moisture will allow for very mild/warm overnight lows in the upper
80s and lower 90s, expected to be near record warm lows for mid-
August. The prolonged, cumulative effect of the hot temperatures,
humidity, and little overnight relief will yield widespread
Moderate and Major HeatRisk, thus the Extreme Heat Warning remains
in effect for portions of southern Nevada, southeastern
California, and northwestern Arizona Tuesday morning through
Friday evening. An uptick in monsoonal moisture late week into the
weekend will provide relief, with a cooling trend expected in
both daytime highs and overnight lows.

The aforementioned uptick in moisture will be driven by a trough
progged to take shape off of the Pacific Coast late this week,
resulting in an eastward shift of the ridge of high pressure
closer to the Four Corners. Ensembles are in agreement that this
shift in the upper pattern will also allow for a return of
thunderstorm chances, possibly as early as Thursday afternoon for
portions of Mohave County, gradually expanding northward and
westward through the weekend. While precise timing and location
remains uncertain at this time, those who have outdoor plans late
week into the weekend should stay on top of the latest forecast
and plan accordingly. Stay tuned.

&&

.AVIATION...For Harry Reid...For the 00Z Forecast
Package...Light southeast winds with occasional gusts to ~15 knots
will trend southerly by 00z and remain southerly through the evening
and overnight hours.  Southerly winds will return tomorrow afternoon
after 20z. Temperatures today will be above 100 degrees through 03Z,
and climb above 100 degrees again tomorrow by 19Z.

For the rest of southern Nevada, northwest Arizona and southeast
California...For the 00Z Forecast Package...Winds across the region
will generally follow typical daily directional patterns, remaining
around 5-10KT through the forecast period. Exceptions include the
northern Owens Valley, including KBIH, where up-valley winds gusting
to around 25KT are expected this afternoon through sunset, and KDAG
in the western Mojave Desert where west-southwesterly winds become
gusty late afternoon through late evening, remaining elevated around
10-12KT thereafter. VFR conditions with FEW-SCT clouds around 10-
20kft can be expected.

&&

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

&&

$$

DISCUSSION/AVIATION...Phillipson


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