Alert archive / Nevada / Flash Flood Warnings in 2021

Flash Flood Warning 8, NWS Reno, NV

July 31, 20214 counties in Nevada

NWS Reno, NV issued this flash flood warning at Jul 31, 2021, 8:02 PM PDT for 4 counties in Nevada. It was in force for 118 min. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued
Jul 31, 2021, 8:02 PM PDT (03:02 UTC)
Expired
Jul 31, 2021, 10:00 PM PDT
In force
118 min
Issued by
NWS Reno, NV
Area
Storm-based polygon
Flood severity
None

Counties Churchill County, NV, Lyon County, NV, Storey County, NV, Washoe County, NV

The radar

The Reno radar (KRGX), 27 km from the middle of the area, began a volume at 03:04 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

The nearest sounding before it

Reno, NV (KREV), launched 00:00Z, 3.0 hours before the alert went out and 84 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.

Skew-T log-pSkew-T log-p diagram, Reno, NV at 00:00Z on 2021-08-01Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 143 joules per kilogram.LCLEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Reno, NV at 00:00Z on 2021-08-01The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -31 square meters per square second.193958Sfc1 km3 km6 km9 kmRMLM
The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.
Mixed-layer CAPE
143 J/kg
Mixed-layer CIN
-11 J/kg
Mixed-layer LCL
2759 m above ground
0-6 km bulk shear
9 kt
0-1 km storm-relative helicity
-31 m²/s²
0-3 km storm-relative helicity
-40 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

699 
WGUS55 KREV 010302
FFWREV
NVC001-019-029-031-010500-
/O.NEW.KREV.FF.W.0008.210801T0302Z-210801T0500Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Reno NV
802 PM PDT Sat Jul 31 2021

The National Weather Service in Reno has issued a

* Flash Flood Warning for...
  Western Churchill County in west central Nevada...
  North Central Lyon County in west central Nevada...
  Storey County in western Nevada...
  Southern Washoe County in western Nevada...

* Until 1000 PM PDT.

* At 802 PM PDT, Doppler radar indicated thunderstorms producing 
  torrential rainfall across along portions of I-80 from Wadsworth 
  through northern Lyon County near mile marker 65. Up to 1 to 2 
  inches of rain has fallen. Flash flooding is ongoing or expected 
  to begin shortly.

  HAZARD...Flash flooding caused by thunderstorms.

  SOURCE...Radar.

  IMPACT...Flash flooding of small creeks and streams, urban
           areas, highways, streets and underpasses as well as
           other poor drainage and low-lying areas.   Blinding
           downpours and ponding of water is possible along I-80.
           Mud and debris flows are possible.

* Some locations that will experience flash flooding include...
  Fernley, Fernley Sink Near I-80 and Wadsworth.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Turn around, don't drown when encountering flooded roads. Most flood 
deaths occur in vehicles.

Be aware of your surroundings and do not drive on flooded roads.

&&

LAT...LON 3963 11930 3974 11913 3972 11908 3967 11901
      3963 11911 3958 11925

FLASH FLOOD...RADAR INDICATED

$$

TF
2 follow-up statements
686 
WGUS75 KREV 010317
FFSREV

Flash Flood Statement
National Weather Service Reno NV
817 PM PDT Sat Jul 31 2021

NVC001-019-029-031-010500-
/O.CON.KREV.FF.W.0008.000000T0000Z-210801T0500Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Churchill NV-Lyon NV-Storey NV-Washoe NV-
817 PM PDT Sat Jul 31 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 10 PM PDT THIS 
EVENING FOR WESTERN CHURCHILL, NORTH CENTRAL LYON, STOREY AND 
SOUTHERN WASHOE COUNTIES...

At 817 PM PDT, Doppler radar estimates continues to show torrential 
rainfall occurring along Interstate 80 from Wadsworth northeastward 
to near mile marker 65.

Between 2 and 3 inches of rain have fallen. Flash flooding is 
ongoing or expected to begin shortly.

HAZARD...Life threatening flash flooding. Thunderstorms producing
         flash flooding.

SOURCE...Radar.

IMPACT...Life threatening flash flooding of creeks and streams,
         urban areas, highways, streets and underpasses.
         Blinding downpours with mud and debris flows are
         possible with these heavy rainfall rate.

Some locations that will experience flash flooding include...
  Fernley, Fernley Sink Near I-80 and Wadsworth.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Turn around, don't drown when encountering flooded roads. Most flood 
deaths occur in vehicles.

Be aware of your surroundings and do not drive on flooded roads.

&&

LAT...LON 3963 11930 3974 11913 3972 11908 3967 11901
      3963 11911 3958 11925

FLASH FLOOD...RADAR INDICATED
FLASH FLOOD DAMAGE THREAT...CONSIDERABLE

$$

TF
094 
WGUS75 KREV 010459
FFSREV

Flash Flood Statement
National Weather Service Reno NV
959 PM PDT Sat Jul 31 2021

NVC001-019-029-031-010509-
/O.EXP.KREV.FF.W.0008.000000T0000Z-210801T0500Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Churchill NV-Lyon NV-Storey NV-Washoe NV-
959 PM PDT Sat Jul 31 2021

...FLASH FLOOD WARNING WILL EXPIRE AT 10 PM PDT THIS EVENING FOR 
WESTERN CHURCHILL, NORTH CENTRAL LYON, STOREY AND SOUTHERN WASHOE 
COUNTIES...

The heavy rain has ended. However, minor flooding may still be 
ongoing. Any additional rainfall tonight could cause further issues 
for the previously warned area. Please continue to heed remaining 
road closures.

LAT...LON 3963 11930 3974 11913 3972 11908 3967 11901
      3963 11911 3958 11925

$$

The office that day

Everything else NWS Reno, NV issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jul 31, 5:29 PM PDTSpecial Weather StatementREV46 min
Jul 31, 6:39 PM PDTAreal Flood AdvisoryREVMineral3 hr
Jul 31, 6:56 PM PDTFlash Flood WarningREVStorey, Washoe94 min
Aug 1, 2:01 PM PDTAreal Flood AdvisoryREVWashoe119 min

Nearby

Flash Flood Warnings in Nevada, 2021Every flash flood warning in 2021

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.