333
FXUS65 KVEF 272157
AFDVEF

Area Forecast Discussion
National Weather Service Las Vegas NV
257 PM PDT Wed Aug 27 2025

.KEY MESSAGES...

* Isolated to scattered thunderstorms remain possible across the
  area through Friday, with potential diminishing heading into the
  weekend.

* Dry conditions and above normal temperatures return this weekend
  through early next week, with a resurgence of monsoonal moisture
  expected toward the middle of next week.

&&

.DISCUSSION...

The unsettled pattern responsible for the active weather across
southern Nevada, southeastern California, and northwestern Arizona
the past several days continues, with the Four Corners ridge having
slid eastward in response to a shortwave off of the southern
California Coast. Between these two features, southwesterly flow has
developed with subtle embedded vorticity maxima moving over the
region, facilitating what has transitioned to diurnal and
orographically favored thunderstorm development. CAMs are in
agreement that most convection today will be focused across the
higher terrain, with the greatest coverage expected across
northern Inyo County across the Southern Great Basin. While some
drying has occurred as precipitable water (PWAT) values have
dropped from around 200% of normal to 100-150% of normal,
localized flooding due to heavy rain remains a concern with storms
today, especially if storms occur over locations that received
appreciable rainfall earlier this week. Frequent lightning and
gusty winds can also be expected, along with localized blowing
dust and additional development along propagating outflow
boundaries. The aforementioned drying trend will continue,
however, and given a decrease in upper level support as the
shortwave dampens, thunderstorm activity will gradually wane
through the end of the week, becoming more isolated in nature and
largely diminishing in time for the start of the Labor Day holiday
weekend. In spite of a fetch of midlevel moisture associated with
TS Juliette that`s expected to be routed over the region Thursday
into Friday, only an uptick in cloud cover is expected, rather
than additional rain chances.

As the aforementioned shortwave weakens this weekend, the ridge is
progged to retrograde across the Four Corners Region and build
further over the Desert Southwest. This will yield a continued
drying trend, with increasing thicknesses allowing for a quick
rebound to near and above normal temperatures this weekend into
early next week. While ridging will be the rule locally, ensembles
indicate another trough taking shape off of the Pacific Northwest
late this weekend, which could act to once again deamplify and
displace the ridge eastward, allowing for a return of monsoonal
moisture in the first half of next week. This uptick in moisture
and ascent provided by the trough as it translates inland brings
low-order PoPs back to southern and eastern areas the first half
of next week, with another shot at some much-needed rainfall for
locations that have missed out so far this week. Stay tuned.

&&

.AVIATION...For Harry Reid...For the 00Z Forecast Package...The
primary concern remains isolated thunderstorms developing over
the higher terrain surrounding the Valley early the forecast
period. There is low confidence regarding whether outflow from
these storms could impact the terminal, with only a low (~10-20%)
chance for impacts in the Valley. Barring outflow boundaries or
storms developing into the Las Vegas Valley, prevailing winds will
be light and generally follow diurnal patterns veering to the
southwest by early evening, and around to the southeast by
tomorrow early afternoon. Increasing mid and high clouds are
expected tonight onward, with VFR conditions prevailing and
temperatures remaining under 100F.


For the rest of southern Nevada, northwest Arizona and southeast
California...For the 00Z Forecast Package...Isolated to widely
scattered thunderstorms will continue across the region through
early this evening, with greater confidence across northern Inyo
County and the southern Great Basin, along I-40 across eastern San
Bernardino County into northwestern Arizona, as well as across
area mountains. Erratic gusty winds and lightning strikes are
expected with storms, with activity quick to diminish after
sunset. Outside of storms or outflow boundaries, winds will
generally remain around 10-12KT or less, following typical diurnal
patterns. VFR conditions prevail, with increasing mid and high
clouds tonight onward.

&&

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

&&

$$

DISCUSSION/AVIATION...Phillipson


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