167
FXUS65 KREV 030951
AFDREV

Area Forecast Discussion
National Weather Service Reno NV
251 AM PDT Wed Sep 3 2025

.KEY MESSAGES...

* Thunderstorm chances decrease today, but the Sierra and the
  Nevada Basin and Range continue with the best chances. The risk
  for heavy rain persists south of I-80.

* Areas of smoke and haze continue to locally impact visibility
  and air quality due to fires in the Sierra.

* Thunderstorm chances persist through the end of the week, with a
  potential for cooler temperatures and increasing winds this
  weekend into early next week.

&&

.DISCUSSION...

Water vapor satellite imagery currently shows the center of an
embedded upper low in northern California. Models have this low
continuing its northward trajectory, as such, the few rain
showers observed early this morning on radar will move north as
they slowly dissipate by sunrise. Patchy fog and low clouds will
develop in the Sierra in response to yesterday`s precipitation.
Also smoke from CA wildfires remains a concern for portions of
the Sierra down to Mono county through the day. Although hi-res
model projections don`t look terrible compared to previous days.

Showers and thunderstorms return this afternoon. However, they
will be more isolated, mainly affecting portions of the Sierra and
the eastern portions of Churchill and Pershing counties. Any storm
will be capable of producing small hail, dry lightning outside or
rain cores, gusty outflow winds, periods of moderate to heavy rain
and gusty outflow winds greater than 45 mph. Some HREF members show
some decent storms this afternoon in the Basin and Range. So watch
out for those gusty winds as they have the potential to create
blowing dust in the playas, and reduce visibilities down to 3 miles
or less. Furthermore, even though the precipitation chances have
come down, the risk for flash flooding and mudslides near steep-
terrain persist for areas south of I-80. WPC is still has a
Marginal Risk (5%) of flash flooding today through Friday.

Drier conditions are expected on Thursday with only 10-20% chance
of storms, as there is some weak ridging trying to sneak in.
However, it will not last long as another shortwave approaches the
area by Friday. This will bring a slight bump to our precipitation
chances. Although the best chances, 30-50%, will be east of US-95
in Mineral, Churchill and Pershing county. The rest of the region
keeps the 10-20% chance of storms as we continue to dry out.

The weekend, looks mostly dry as the upper trough shoves away the
monsoonal moisture that we had in place. This new pattern brings
back the potential for increasing winds and cooler temperatures.
NBM guidance keeps a 30-60% chance of wind gusts exceeding 30 mph
through the weekend and early next week focusing in mountain ridges,
NE CA and northern Washoe county. The cooling trend continues this
weekend, as temperatures tumble to around 5 degrees below normal
with afternoon highs in the low to mid 80s western NV and NE CA,
and low to mid 70s Sierra communities.

It looks like more troughs will be passing through next week which
may keep some winds in the forecast, but more significantly cooler
temperatures with afternoon highs potentially in the mid 70s for
western NV, and mid 60s for Sierra communities. Is that you fall?

-HC

&&

.AVIATION...

Mostly VFR conditions are expected through Thursday morning. The
exceptions will be VIS reductions from smoke and haze by CA
wildfires affecting mainly the Sierra and Mono county. Also
expect slantwise VIS reduction due to the HZ through the region.

Storms return to the Sierra and the NV Basin and Range between
19Z-03Z. MVFR to IFR conditions are likely with any storm due to
reductions in VIS and lower CIGS. Gusty outflow winds greater than
40 kts are likely again. These could lead to patchy BLDU near playas
in the Basin and Range with VIS down to 3 SM or lower at times.

Patchy fog is expected at KTRK from 07Z-15Z, then there is a 30%
chance it returns again tonight from 09Z-15Z.

-HC

&&

.FIRE WEATHER...

Shower and storm activity decreases today through Friday to
around 10-40%. Although the risk of dry lightning away from rain
cores, heavy rainfall, and gusty outflow winds continues.

This weekend, a cooler and breezier pattern returns with the
approach of another upper trough. This pattern could lead to
isolated elevated concerns in mountain ridges and over NW NV and
NE CA if it were to persist. Currently, NBM guidance keeps a
30-60% chance of wind gusts exceeding 30 mph through the weekend
and early next week in the aforementioned areas. These winds could
fan out any new holdover fires from the thunderstorms this week.

-Jim/HC

&&

.REV Watches/Warnings/Advisories...
NV...None.
CA...None.
&&

$$