181
FXUS65 KREV 231753
AFDREV

Area Forecast Discussion
National Weather Service Reno NV
1053 AM PDT Sat Aug 23 2025

.KEY MESSAGES...

* Heat continues today with Major HeatRisk in lower elevations
  across northeast CA and northwest-west central NV.

* Afternoon shower and thunderstorm chances continue today through
  mid-week, bringing frequent lightning, small hail, gusty winds,
  and flooding potential.

* The greatest chances for flooding will take place Sunday through
  Tuesday, with the highest risk for flash flooding over burn
  scars such as the Davis and Connor.

&&

.DISCUSSION...

Clear skies this morning will allow for ample heating through this
afternoon. Additionally, model guidance shows areas of diffluence
centered over the Reno-Carson-Minden area as well as over Alpine
county today. These two will bring the instability required for
afternoon showers and thunderstorms. As of this writing, cells
are starting to populate along the far southern reaches of the
Sierra, pushing into southwest Mono county. Southerly flow aloft
will bring storms north today into the Reno-Carson-Minden area.
Thunderstorm chances will range from 40-70%, with chances dropping
dramatically as you progress north of Pyramid Lake and into the
Black Rock Desert (less than 25%). Similarly, out in the Basin and
Range, chances drop considerably north of Lovelock.

This morning`s sounding recorded 0.83 inches of PWAT as well as
1200 J/kg of DCAPE. That 0.83 inches of PWAT sits above the 90th
percentile for our area; keeping in mind that 0.75 inches is a
good basis for us to get flooding here, we have gone ahead and
issued a Flash Flood Watch. This is in effect until 10 PM today
for the Reno-Carson-Minden area as well as Mono, Mineral, and S
Lyon counties. The threat for flash flooding will be greatest over
burn scars, most notably the Davis, Connor, and Tamarack burn scar
areas. However, low-lying and flood-prone areas will be
susceptible to flooding due to excessive rainfall (5% chance, from
the Weather Prediction Center) and runoff.

While the bulk of the storms are expected to taper after sunset
tonight, there is an additional risk for overnight convection
(15% chance). Locations of concern will primarily be in NW NV and
NE CA, including the Black Rock Desert. Model guidance shows
possible forcing, however confidence is low.

Storm chances continue each afternoon through mid-week, with the
greatest chances for flooding primarily Sunday through Tuesday. A
shortwave off of the coast of California Monday may bring
additional forcing for thunderstorms. However, just how much that
influences our area is yet to be determined. With the influx of
moisture being driven in from the Four Corners high, PWAT values
increase each day. This may result in lingering cloud cover
overnight, possibly reducing the chances for afternoon
thunderstorm development. While we are expecting chances each
afternoon, this is something to keep in mind as we take things
day-by-day.

Afternoon highs will reach around 100 today for NW NV, primarily
for the lower deserts. Major HeatRisk is also expected for those
areas today, including the Black Rock Desert. Warm overnight lows
again tonight will bring little relief, thus, we have continued
our Heat Advisory through Sunday morning. Afternoon highs drop
considerably starting Sunday, with highs 5-10 degrees cooler than
today. A cooling trend will continue through next week, bringing
afternoon highs back down to near normal.

-Giralte

&&

.AVIATION...

A monsoon moisture push will provide widespread coverage of showers
and thunderstorms this afternoon. Main operational impacts with
these storms will include periods of IFR conditions due to storms
producing heavy rain and sudden reductions to visibility. Storms
are capable of producing 0.25-0.75" of rain in individual storm
cores, along with small hail, lightning, and outflow gusts up to
40 kts.

Precipitation chances are highest at KMMH (70-75% chance) with 50-60%
chances for the other main terminals. Main window for T-Storms
across KMMH will be 18-00z, and 20-03z for Sierra and W.Nevada
terminals this afternoon.

Thunderstorm chances decrease northward of I-80 this afternoon but
still could see 30-40% chances after about 01z late this afternoon.
However these areas, including KLOL, SVE, and the Black Rock
Airport (88NV), could continue to see density altitude concerns
due to ongoing heat until showers and storms reach the region.
Outflow gusts will also be capable of producing reduced visibility
in blowing dust. An active thunderstorm pattern is expected to
continue through the middle of next week. Fuentes

&&

.FIRE WEATHER...

A monsoon moisture push will produce widespread coverage of showers
and thunderstorms this afternoon and evening. These storms will be
fast moving storms but will contain copious moisture with them,
resulting in a risk of heavy rain, small hail, flash flooding in
burn scar areas, and gusty outflow winds.

Nocturnal thunderstorms will be possible tonight across portions of
NW Nevada into far NE California as an upper level disturbance
tracks through overnight. While isolated strikes are possible
outside of storm cores, any dry lightning potential will be limited
(less than 10%) as wetting rain chances reach 20-30% in these areas.
Fuentes

&&

.REV Watches/Warnings/Advisories...
NV...Heat Advisory until 9 AM PDT Sunday NVZ004-005.

     Flood Watch until 10 PM PDT this evening NVZ001-003.

CA...Heat Advisory until 9 AM PDT Sunday CAZ071.

     Flood Watch until 10 PM PDT this evening CAZ073.

&&

$$