664
FXUS65 KVEF 220510
AFDVEF

Area Forecast Discussion
National Weather Service Las Vegas NV
1010 PM PDT Mon Jul 21 2025

.KEY MESSAGES...

* Isolated showers and thunderstorms will be possible across
  northwestern Arizona each afternoon through the middle of the week.

* Cooler than normal temperatures will continue through the end of
  the week.

&&

.DISCUSSION...through this weekend.

A shortwave trough will roll through the Pacific Northwest today and
tomorrow, resulting in breezy southerly wind across east-central
California and southern Nevada this afternoon and again tomorrow
afternoon. These winds combined with low relative humidity values
and dry fuels will result in critical fire weather conditions across
the Nevada National Security Site today. As such, a Red Flag Warning
has been issued for Nevada Fire Weather Zone 462. More information
regarding this headline can be found in the FIRE WEATHER section
below.

As the aforementioned shortwave rolls through the Pacific Northwest,
we will transition to dry southwesterly flow aloft, which will push
moisture off to the east and out of our forecast area. As this
moisture is slowly scoured out over the next few days, portions of
Mohave County will see 15 to 25 percent chance for isolated showers
and thunderstorms each afternoon through Wednesday. In order for
precipitation to make it to the surface, it will have to overcome
the dry lower-levels of the atmosphere with virga showers more
likely than measurable precipitation. Any convection that does
develop this afternoon will dissipate with the loss of daytime
heating after sunset. Outside of Mohave County, dry conditions
will continue into the weekend.

As the shortwave moves through the Pacific Northwest today and
tomorrow, it will leave an area of elongated troughing in its wake.
This will eventually become a closed low pressure system off the
coast of California. The primary impact of this cut-off low in our
forecast area will be lower 500 mb heights that will allow cooler
than normal temperatures to linger through the end of the work week
and into the weekend.

&&

.FIRE WEATHER...Breezy southerly to southwesterly winds will pick up
again Tuesday afternoon. However, these winds will not be as strong,
which will help to mitigate fire weather risk.
&&

.AVIATION...For Harry Reid...For the 06Z Forecast Package...VFR
conditions will prevail through the TAF period with no operationally
significant clouds. Breezy south to southeast winds with 20 to 25
knot gusts will persist through about midnight before diminishing.
Southerly winds will increase again late Tuesday morning, with gusts
around 20 knots expected through sunset. Temperatures will get very
close to, but may not quite reach, 100F between 22Z and 00Z.

For the rest of southern Nevada, northwest Arizona and southeast
California...For the 06Z Forecast Package...Thunderstorm chances on
Tuesday afternoon and evening should be limited to eastern and
southern Mohave County, with VFR conditions expected around the rest
of the region. Southerly winds gusting 15 to 25 knots will be common
again Tuesday, with the usual local effects on wind direction.
&&

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

&&

$$

DISCUSSION/FIRE WEATHER...Stessman
AVIATION...Morgan


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