Flash Flood Warning 5, NWS Reno, NV

Area Forecast Discussion
National Weather Service Reno NV
1200 PM PDT Wed Aug 12 2026

.KEY MESSAGES...

* Showers and thunderstorms widespread today and tomorrow with risk
  of heavy rains and flash flooding. Possible showers overnight
  tonight.

* Temperatures cooling to near or below normal levels through the
  weekend along with typical afternoon breezes.

* No significant heat or strong wind events indicated into next
  week.

&&

.DISCUSSION...

* Showers and t-storms are a good bet (30-80% chances) this
  afternoon through early evening, mainly along and east of Hwy 395
  per the latest HREF/NBM guidance. Main concern is locally heavy
  rain with rates 1-1.5"/hour along with erratic outflows and
  lightning. Thursday appears to be the highest risk of heavy rains
  with another round of showers/storms forecast. If the stars align
  and we don't cloud over, storms could produce rainfall amounts of
  1.5-2.5"/hour, as such WPC has placed much of the region in a rare
  slight risk for excessive rainfall Thursday. Flood Watches in
  effect today and tomorrow.

* Impacts wise the major concern is recent and ongoing wildfire burn
  areas being more susceptible to flash flooding, mud slides, and
  debris flows - so we will be quick to warn on these spots. The
  Stallion Fire is notable with steep terrain and a history of
  debris flows from fires in the vicinity in the last 5-10 years.
  New fire starts from lightning outside storm cores are certainly
  possible with very dry vegetation, and outflow winds of 30-40 MPH
  could drive fire in random directions rather suddenly. HREF
  suggesting outflows nearing 60 MPH over the dry lake beds between
  Fallon-Winnemucca today and tomorrow, so blowing dust will be a
  concern.

* Sufficient moisture and instability is present for overnight and
  early morning showers and isolated storms. HREF is showing this
  nicely over Western Nevada, Tahoe, and the eastern Sierra tonight,
  roughly 20-40% odds. Either way, storm initiation Thursday will be
  earlier than normal, early-mid morning most likely. If we do cloud
  over quickly tomorrow, on the other hand, then that could reduce
  the intensity of storms/rainfall rates.

* Going into Friday, a bit drier airmass works in but instability
  remains and with upper trough to our west, chances for storms
  continue but at a lower confidence level. Roughly 10-20% along Hwy
  395 up to 30-40% out along Hwy 95.

* For the weekend into early next week, airmass continues to dry but
  not too excessively and temperatures remain near to just below
  seasonal normals, coupled with daily zephyr breezes. Guidance is
  not showing anything too strong on the winds, 10-15 MPH gusting to
  20 MPH in the afternoons, so that is good news for any continuing
  fire suppression efforts.

-Chris

&&

.AVIATION...

* Showers and t-storms are a good bet (30-80% odds) near and east of
  RNO-CXP-MEV-MMH today, with more widespread activity forecast for
  Thursday (50-90% most areas, with 30-40% in the Sierra around
  TRK/TVL). MVFR-IFR conditions possible in heavy rains, lightning,
  and erratic outflow winds of 25-35 knots. Blowing dust also
  possible around HTH/NFL/LOL both days.

* Airmass is moist and unstable enough to allow for showers and
  isolated storms overnight tonight into Thursday morning, 10-30%
  chances. But the most favored times for storms remain the
  afternoon and early evening.

* Wildfires, specifically the large Bug/Stallion Fires N of RNO,
  will continue to produce haze and smoke restrictions to visibility
  (5-10 SM) through at least Thursday depending on fire activity.
  Winds are more variable today/tomorrow so smoke forecasts are low
  confidence. New fire starts from lightning also could add to
  smoke/haze levels.

-Chris

&&

.FIRE WEATHER...

* Obvious concerns are with thunderstorms today and tomorrow
  producing heavy rains, strong outflow winds, and new lightning
  starts outside the cores.

* Flood Watch in effect today and tomorrow 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 both days.

* Outflow winds producing sudden shifts in fire behavior and
  direction are also a concern both days. Latest high resolution
  models indicating potential for gusts of 30-40 MPH close to active
  fires, with potential for gusts over 50 MPH out east toward the
  Highway 95 corridor.

* New lightning starts given the very dry fuels are a definite
  possibility. While heavy rains are favored from storms, lightning
  outside storm cores can still produce new starts or holdovers that
  simmer for several days or longer. Fire Weather Watch in effect
  for the Tahoe Basin Thursday as that has the nexus of slightly
  drier storms and quicker storm motions, but admittedly confidence
  is low.

* Also of note is potential for overnight showers and storms tonight
  into Thursday morning - roughly 20-40% chances. So the risk of
  lightning and outflows and brief heavy rains doesn't necessarily
  die off when the sun goes down.

-Chris

&&

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

     Flood Watch from Thursday afternoon through Thursday evening
     NVZ004.

CA...Fire Weather Watch from late tonight through Thursday evening
     CAZ272.

     Flood Watch through Thursday evening CAZ073.

&&

Special Weather Statement
National Weather Service Reno NV
1141 AM PDT Wed Aug 12 2026

CAZ072-073-NVZ001-003-004-122030-
Greater Lake Tahoe Area CA-Mono CA-
Western Nevada Basin and Range including Pyramid Lake NV-
Greater Reno-Carson City-Minden Area NV-
Mineral and Southern Lyon Counties NV-
1141 AM PDT Wed Aug 12 2026

...STRONG THUNDERSTORMS WILL IMPACT THE EASTERN SIERRA AND WESTERN
NEVADA THROUGH 130 PM PDT...

At 1139 AM PDT, strong thunderstorms were developing across Mono,
Mineral, southern Lyon, and Douglas counties. These storms will
increase in coverage northward through the afternoon.

HAZARD...Wind gusts 40 to 50 mph, half inch size hail, heavy
         rainfall with the potential for flash flooding, and blowing
         dust downwind of dry sinks and playas.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects. Minor hail damage to vegetation is
         possible. Heavy rain may cause flash flooding, debris flows
         and flooded roads. Blowing dust could lower visibility and
         make travel dangerous.

Locations impacted include...
Reno, Carson City, Fallon, Mammoth Lakes, Chalfant, Crowley Lake,
Sonora Pass, Gardnerville, Virginia City, June Lake, Lee Vining, Twin
Lakes, Lahontan Reservoir, Toms Place, Bodie, Benton, Bridgeport,
Mono Lake, Coleville, and Topaz Lake.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

Turn around, don't drown when encountering flooded roads.

&&

LAT...LON 3758 11901 3774 11913 3773 11926 3788 11920
      3804 11931 3820 11963 3845 11968 3860 11987
      3920 11981 3969 11988 3966 11747 3953 11750
      3938 11776 3910 11778 3900 11819 3847 11770
      3789 11842 3747 11783 3746 11784 3746 11878
TIME...MOT...LOC 1835Z 201DEG 12KT 4168 11769

MAX HAIL SIZE...0.50 IN
MAX WIND GUST...50 MPH

CJ

Special Weather Statement
National Weather Service Reno NV
134 PM PDT Wed Aug 12 2026

CAZ072-073-NVZ001-003>005-122215-
Greater Lake Tahoe Area CA-Mono CA-
Western Nevada Basin and Range including Pyramid Lake NV-
Northern Washoe County NV-Greater Reno-Carson City-Minden Area NV-
Mineral and Southern Lyon Counties NV-
134 PM PDT Wed Aug 12 2026

...STRONG THUNDERSTORMS WILL IMPACT THE EASTERN SIERRA AND WESTERN
NEVADA THROUGH 330 PM PDT...

At 125 PM PDT, strong thunderstorms continue to develop across the
eastern Sierra and western Nevada. These storms will increase in
coverage northward through the afternoon.

HAZARD...Wind gusts 40 to 50 mph, half inch size hail, heavy
         rainfall with the potential for flash flooding, and blowing
         dust downwind of dry sinks and playas.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects. Minor hail damage to vegetation is
         possible. Heavy rain may cause flash flooding, debris flows
         and flooded roads. Blowing dust could lower visibility and
         make travel dangerous.

Locations impacted include...
Reno, Carson City, Fallon, Mammoth Lakes, Chalfant, Crowley Lake,
Sonora Pass, Gardnerville, Virginia City, June Lake, Pyramid Lake,
Lee Vining, Twin Lakes, Lahontan Reservoir, Toms Place, Bodie,
Benton, Bridgeport, Mono Lake, and Coleville.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

Turn around, don't drown when encountering flooded roads.

&&

LAT...LON 3773 11926 3788 11920 3804 11931 3820 11963
      3845 11968 3866 11994 3920 11981 3945 11983
      3950 11995 4007 11995 4006 11752 3955 11749
      3938 11776 3910 11778 3900 11819 3847 11770
      3789 11842 3747 11783 3746 11784 3746 11878
TIME...MOT...LOC 2019Z 200DEG 18KT 4386 11641

MAX HAIL SIZE...0.50 IN
MAX WIND GUST...50 MPH

CJ

Preliminary Local Storm Report
National Weather Service Reno NV
309 PM PDT Wed Aug 12 2026

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0300 PM     Rain             5 E Gardnerville        38.94N 119.65W
08/12/2026  E1.10 Inch       Douglas            NV   Trained Spotter

            2-hr Storm Rainfall Total.

&&

Special Weather Statement
National Weather Service Reno NV
315 PM PDT Wed Aug 12 2026

CAZ072-073-NVZ001>005-130015-
Greater Lake Tahoe Area CA-Mono CA-Greater Lake Tahoe Area NV-
Western Nevada Basin and Range including Pyramid Lake NV-
Northern Washoe County NV-Greater Reno-Carson City-Minden Area NV-
Mineral and Southern Lyon Counties NV-
315 PM PDT Wed Aug 12 2026

...STRONG THUNDERSTORMS WILL IMPACT THE EASTERN SIERRA AND WESTERN
NEVADA THROUGH 515 PM PDT...

At 310 PM PDT, strong thunderstorms continue to develop across the
eastern Sierra and western Nevada. These storms will increase in
coverage northward through the late afternoon.

HAZARD...Wind gusts 40 to 50 mph, up to penny size hail, heavy
         rainfall with the potential for flash flooding, and blowing
         dust downwind of dry sinks and playas.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects. Minor hail damage to vegetation is
         possible. Heavy rain may cause flash flooding, debris flows
         and flooded roads. Blowing dust could lower visibility and
         make travel dangerous.

Locations impacted include...
Reno, Carson City, South Lake Tahoe, Fallon, Mammoth Lakes, Chalfant,
Crowley Lake, Sonora Pass, Gardnerville, Virginia City, June Lake,
Pyramid Lake, Lee Vining, Twin Lakes, Lahontan Reservoir, Incline
Village, Toms Place, Bodie, Benton, and Bridgeport.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

Turn around, don't drown when encountering flooded roads.

&&

LAT...LON 3774 11913 3773 11926 3788 11920 3804 11931
      3820 11963 3845 11968 3872 11999 4016 12000
      4015 11747 4000 11754 3988 11746 3955 11749
      3938 11776 3910 11778 3900 11819 3847 11770
      3789 11842 3747 11783 3746 11878
TIME...MOT...LOC 2211Z 193DEG 7KT 4194 11863

MAX HAIL SIZE...0.75 IN
MAX WIND GUST...50 MPH

CJ