181
FXUS65 KVEF 202333
AFDVEF

Area Forecast Discussion
National Weather Service Las Vegas NV
433 PM PDT Thu Aug 20 2026

.KEY MESSAGES...

* Warm temperatures continue with above- normal afternoon highs and
  near-record morning lows.

* Thunderstorm chances return to the forecast today as monsoon
  moisture increases, with the highest confidence and most
  widespread storm coverage on Friday.

&&

.DISCUSSION...Through Early Next Week.

Under partly to mostly sunny skies, high pressure remained in place
over the region today. While moisture has notably increased in
portions of the Colorado River Valley and southern Mohave County, it
still remained dry enough for temperatures to quickly warm and above
normal temperatures are expected again this afternoon. Additional
moisture will advect north and west tonight, which will keep
overnight lows tonight mild. While this moisture will be around on
Friday, it will not be as robust or long lived as previous forecasts
suggested. This will result in a slight cool down on Friday but high
temperatures will still run 2-3 degrees above normal. With less
moisture and cloud cover this weekend, temperatures then warm a
degree or two Saturday and Sunday from Friday. An Extreme Heat
Warning remains in effect through Friday afternoon for desert
valleys, will continue to assess the need for an extention of
products into the weekend as probabilities of about 50% for Major
HeatRisk exists in many areas where the current product is in
effect.

As previously mentioned, moisture will shift into southern portions
of the area this afternoon then continue to advect north and west on
Friday. This will bring a return of thunderstorm chances to the
region. Isolated convection in the terrain of Mohave County today
afternoon with a lower chance for thunderstorms in the Western
Mojave Desert ahead of a decay MCV evident on satellite. Some models
show scattered showers will continue in northern  Mohave County
tonight pushing into Clark County Friday morning, but this is low
confidence and would remain low impact even if it did occur. More
likely will be thunderstorms developing on the terrain of Southern
Nevada and western Arizona Friday afternoon. These storms may
struggle on Friday as dry air caps their development, thus limiting
coverage into the evening hours. Overall, Friday`s storms will be
less widespread and impactful than storms last week, though any
storm will have the capability of producing locally heavy rain,
isolated flash flooding, lightning, and sudden gusty winds. On
Saturday, the upper level flow turns southwest ahead of an incoming
trough. This will advect drier air into the region and shove the
high over the Four Corners region east, which is not ideal for local
monsoon set ups. This weekend`s thunderstorm chances will depend on
how quickly the moisture is scoured out as upper level dynamics are
introduced with the trough. Current forecast is fairly dry for this
weekend with only a slight chances on the Sierra into the terrain of
the Southern Great Basin, but if moisture lingers longer this may
change. Anyone with weekend plans should monitor later forecasts as
details come together. Looking towards early next week, confidence
is marginal in how much moisture will be around and how widespread
storm coverage could be as the trough and area of high pressure
compete in the overall synoptic setup.

&&

.AVIATION...For Harry Reid...For the 00Z Forecast Package...Gusty
southwesterly winds should weaken after sunset, eventually
becoming variable late overnight. Friday`s wind pattern will be
similar to today, with breezy southeasterly winds in the morning
strengthening and shifting to the southwest in the afternoon.
There is a 10 to 20 percent chance of showers and thunderstorms
around the Las Vegas Valley in the afternoon, some of which may
occur within the vicinity of the terminal. Storm development will
stop after sunset, and winds will fall to less than 10 knots out
of the southwest. Temperatures fall to less than 100 degrees
through 03Z, then climb back above 100 degrees by 18Z.

For the rest of southern Nevada, northwest Arizona and southeast
California...For the 00Z Forecast Package...Winds will weaken and
storm activity will wane after sunset. The usual gusty westerly
winds will also pick up at KDAG. For Friday, breezy southerly to
southwesterly winds will develop in the Las Vegas Valley and Owens
Valley in the afternoon. Isolated showers and thunderstorms also
return in the afternoon across northwestern Arizona and parts of
southern Nevada, favoring high terrain. Some convection may occur
within the vicinity of terminals in the Las Vegas Valley. Winds and
storms should weaken after sunset.

&&

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

&&

$$

DISCUSSION...Nickerson
AVIATION...Meltzer

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