990
FXUS65 KREV 131011
AFDREV

Area Forecast Discussion
National Weather Service Reno NV
311 AM PDT Thu Aug 13 2026

.KEY MESSAGES...

* Showers and thunderstorms become widespread this afternoon with
  primary risks of heavy rain capable of flash flooding and
  frequent lightning, along with outflow wind gusts and hail.

* Isolated showers and thunderstorms may return Friday afternoon
  but with a much lower risk of flash flooding.

* Drier conditions prevail this weekend through early next week
  with temperatures a few degrees below mid-August averages.

&&

.DISCUSSION...

* An area of low pressure off the southern CA coast is currently
  producing isolated showers and t-storms in the San Joaquin
  valley. The more southerly position of this low will keep most
  forcing through mid-morning south and west of the Sierra and
  western NV, with precip limited to isolated showers and less
  than 10% chance of lightning.

* By late morning through early afternoon, this low then ejects
  northward toward the Sierra, providing more substantial forcing
  to combine with the moisture in place, with decent instability
  (CAPE values between 500-1000 J/kg). Higher resolution guidance
  continues to support rapid t-storm development between 10 AM-12
  noon for the eastern Sierra, then between noon and 2 PM for far
  western NV including areas around the Bug and Stallion fires.
  These storms could develop into more persistent clusters as they
  march across the remainder of western NV through the rest of
  this afternoon, although some areas will miss out on more
  intense rainfall due to a broader cloud shield spreading out
  from these clusters and reducing heating/instability. Although
  most of the cells are expected to push east or northeast,
  rebuilding on the back side and outflow interactions could
  prolong the storm threat back to near the US-395 corridor and
  the Bug/Stallion fires until about 6-7 PM.

* While heavy rainfall (rates of 1-2+"/hour) capable of flash
  flooding and frequent lightning are the primary risks, strong to
  isolated severe wind gusts and potential for accumulating hail
  (mainly small but can`t rule out 1" hail size either) are also
  in the mix with these storms.

* Later this evening, leftover showers wind down in west central
  NV with the low exiting to the north of CA/NV. Then for Friday,
  a weaker trough shortwave hangs back near the CA coast and
  provides a bit of instability along with residual moisture.
  While flooding risks are lower given weaker forcing and
  decreasing PW values compared to today, isolated PM showers and
  t-storms could form with up to 20% chance for the eastern Sierra
  and far western NV, and about 30% chance near US-95.

* For the weekend into early next week, a quieter weather pattern
  prevails with a modest SW flow over the Sierra keeping mainly
  dry and mild conditions, as temperatures settle in the 80s to
  near 90 degrees for lower elevations and 70s for Sierra
  communities. The next chance for showers and increased breezes
  may return around the middle of next week, but confidence is
  lower. MJD

&&

.AVIATION...

* Showers and t-storms increase after 18Z for the eastern Sierra
  including KMMH, and after 20Z for KRNO-KCXP-KMEV, with the
  threat (above 50% chance) continuing through 01-03Z. These
  storms will produce periods of MVFR/IFR conditions with heavy
  rain, frequent lightning, and erratic gusts to 35 kt. The Tahoe
  area terminals (KTVL/KTRK) are more likely to be on the western
  fringe of these storms with less than 20% chance of direct
  impacts between 18-22Z, and decreasing further.

* For Friday through the weekend, VFR conditions prevail with SW-W
  gusts generally below 20 kt. Only exception may be a lingering
  10-20% chance of a brief shower or t-storm near KRNO-KCXP-KMEV-
  KMMH Friday afternoon. MJD

&&

.FIRE WEATHER...

* With improved humidity recovery over the Tahoe basin and the
  best forcing associated with the low off the CA coast remaining
  south and west of the Sierra crest, the risk for dry lightning
  strikes has decreased. Therefore we have cancelled the Fire
  Weather Watch.

* Primary concerns are with thunderstorms today producing heavy
  rains, strong outflow winds. While dry lightning potential is
  low due to the much higher humidity with surface dew points in
  the 40s-50s, a few lightning fires could ignite from strikes on
  receptive vegetation outside the rain cores.

* Flood Watch in effect through this evening for increased
  potential of flash flooding, mud slides, and debris flows on
  current and recent burn areas, including the Bug and Stallion
  Fires just north of Reno. Stallion Fire probably slightly higher
  risk with steeper terrain involved, but any rainfall can create
  hazardous conditions for movement of fire personnel. Rainfall
  rates over 1"/hour are expected from any storms this afternoon.

* Outflow winds producing sudden shifts in fire activity and
  direction are also a concern this afternoon. Latest high
  resolution models indicate potential for gusts of 40 MPH close
  to active fires, and over 50 MPH farther east toward the US-95
  corridor.

* While some drying returns this weekend, humidity won`t drop near
  the extreme dry levels prior to this storm event. Afternoon
  minimums look to range from 15-25% with good to excellent
  overnight recoveries. Winds will be on the lighter side with
  typical PM zephyr breezes producing gusts 20-25 mph, but not
  expecting any stronger wind patterns into early next week. MJD

&&

.REV Watches/Warnings/Advisories...
NV...Flood Watch through this evening NVZ001-003.

     Flood Watch from 1 PM PDT this afternoon through this evening
     NVZ004.

CA...Flood Watch through this evening CAZ073.

&&

$$