031
FXUS65 KVEF 280513
AFDVEF

Area Forecast Discussion
National Weather Service Las Vegas NV
1013 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 06Z Forecast Package...Winds
will remain relatively light, 10 knots or less, and will follow
typical diurnal directional trends through tomorrow afternoon. Winds
will pick up and shift to the southeast late tomorrow afternoon.
These breezier southeasterly winds will continue into the evening
hours, accompanied by 15 to 20 knot wind gusts. Winds will decrease
late tomorrow evening, becoming light and variable through the
overnight period. Mid-to-high clouds will continue to filter through
the area with scattered to broken skies for most of the day. Due to
increased cloud cover, temperatures are not expected to exceed 100
degrees in the Las Vegas Valley on Thursday.

For the rest of southern Nevada, northwest Arizona and southeast
California...For the 06Z Forecast Package...Outside of any
convective influence, winds will tend to follow typical diurnal
directional trends through late tomorrow morning/early tomorrow
afternoon when breezy southerly-to-southeastelry winds will pick
up across the area, continuing into the evening hours. Isolated
showers and thunderstorms will pop up in the Sierra and southern
Great Basin tomorrow afternoon. These storms will have the
potential to produce erratic gusty outflow winds, lightning, and
moderate downpours. Mid- to-high clouds will continue to stream
into the area from the southeast with skies becoming scattered to
broken at times.

&&

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

&&

$$

DISCUSSION...Phillipson
AVIATION...Stessman

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