621
FXUS65 KREV 271917
AFDREV

Area Forecast Discussion
National Weather Service Reno NV
1217 PM PDT Wed Aug 27 2025

.KEY MESSAGES...

* Thunderstorms and an elevated risk of flash flooding are expected
  this afternoon, especially over urban areas and burn scars.

* A drying trend will reduce thunderstorm activity into the weekend,
  but areas of isolated storms remain possible into early next week.

* Temperatures remain cooler than normal into the weekend, but
  will warm-up through Sunday.

&&

.DISCUSSION...

A shortwave trough will be passing through today, leaving our CWA on
the edge of the left exit region of the upper level jet streak.
Because of this, another round of showers and t-storms are expected
this afternoon. Thursday, the trough moves further east and shifts
all of its forcing and instability over central/eastern NV. We may
see some chances for showers and storms over Mono/Mineral/E.
Churchill Thursday, though models are still struggling to come to a
consensus on location. Friday through this weekend look to be a bit
quieter. We`ll have less available moisture and less instability to
fire off thunderstorms.

Diving in further on today`s storms: Going through the CAMs, MUCAPE
today will be around 400-600 J/kg and DCAPE around 800-1000 J/kg.
That`s enough DCAPE for storms to produce strong outflow boundaries
that could produce gusts up to 40+ mph. PWAT values are slightly
elevated around 0.75-0.85". Storm motions continue to be on the
slower side today, less than 10 kt, so flash flooding remains a risk
where stronger storms stall out, back build, or train. Especially
since we`ve had multiple rounds of heavy rain over the past few
days, the ground is primed for faster runoff. If you`re out on a
lake today or over in the Black Rock Desert, please be cautious and
have a way to receive weather alerts! Shower and t-storm chances of
30-40% will continue today across the entire CWA, with storms
starting as early as 11 AM. Similar to yesterday, storms will start
along the Sierra and propagate east through the afternoon. Expect
small hail with occasional hail that`s up to a quarter in size,
gusty outflow winds up to 45-50 mph, heavy rain with potential
flash flooding, and possible blowing dust over the playa. I will
note too that ensembles are hinting at the possibility of a trace
of snow this evening in southern Mono and the White Mountains as
showers are dissipating and surface temperatures cool off. While
still a very low probability (<10%), it`s a non-zero chance.

As alluded to earlier, Friday onward we get into this drier pattern
and high pressure starts to work its way in. Ensembles are showing
the possibility of showers in the Sierra each afternoon through the
weekend, however most CAMs don`t show anything in the way of precip,
yet. All the storms aside, for the rest of the week we`re going to
warm up a little bit each day and temps will warm back up in lower
NV valleys to 90 by Saturday.

-Justin

&&

.AVIATION...

Widespread coverage of showers and thunderstorms are expected once
again this afternoon. Brief periods of IFR conditions are
possible due to heavy rain and sudden reductions to visibility.

The best chances for thunderstorms today will be around 60-70% at
KMMH and terminals in the Sierra and Sierra Front, including 40%
at 88NV in the Black Rock Desert. Timing of these storms will be
as early as 12-1 PM for KMMH, 2-5 PM for 88NV, and 12-1 PM for
all other terminals. Main threats today with these storms will be
heavy rain, small hail, frequent lightning, and outflow gusts up
to 35 kts. Storm activity is expected to wrap up after 8 PM.
Additionally, low clouds and fog may produce a period of IFR
conditions at KTRK overnight tonight, particularly 11Z - 16Z.

-Justin

&&

.REV Watches/Warnings/Advisories...
NV...Flood Watch until 10 PM PDT this evening NVZ001>003.

CA...Flood Watch until 10 PM PDT this evening CAZ071>073.

&&

$$