Alert archive / California / Severe Thunderstorm Warnings in 2020

Severe Thunderstorm Warning 21, NWS Reno, NV

July 22, 2020Sierra County, California

NWS Reno, NV issued this severe thunderstorm warning at Jul 22, 2020, 3:44 PM PDT for Sierra County, California. It was in force for 46 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 22, 2020, 3:44 PM PDT (22:44 UTC)
Expired: Jul 22, 2020, 4:30 PM PDT
In force: 46 min
Issued by: NWS Reno, NV
Area: Storm-based polygon
Hail: 1.0 in
Wind: 60.0 mph

County Sierra County, CA

The radar

The Reno radar (KRGX), 74 km from the middle of the area, began a volume at 22:44 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 12:00Z, 10.7 hours before the alert went out and 180 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 12 J/kg
Mixed-layer CIN: -360 J/kg
Mixed-layer LCL: 2655 m above ground
0-6 km bulk shear: 22 kt
0-1 km storm-relative helicity: 9 m²/s²
0-3 km storm-relative helicity: 36 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

923 
WUUS55 KREV 222244
SVRREV
CAC091-222330-
/O.NEW.KREV.SV.W.0021.200722T2244Z-200722T2330Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Reno NV
344 PM PDT Wed Jul 22 2020

The National Weather Service in Reno has issued a

* Severe Thunderstorm Warning for...
  Sierra County in northern California...

* Until 430 PM PDT.

* At 342 PM PDT, a severe thunderstorm was located near Sierraville,
  and is nearly stationary.

  HAZARD...Quarter size hail, 60 mph wind gusts, and heavy rainfall.

  SOURCE...Radar indicated.

  IMPACT...Hail damage to vehicles is expected. Wind damage to 
           roofs, siding, fencing and trees possible. Ponding of 
           water on Highway 89 and local roads likely.

* Locations impacted include...
  Sierraville, Sattley, and Highway 89. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Prepare immediately for hail and damaging winds. People outside 
should move immediately to shelter inside a strong building. Stay 
away from windows.

Heavy rainfall is occurring with this storm, and may lead to flash 
flooding. Do not drive your vehicle through flooded roadways.

&&

LAT...LON 3963 12023 3952 12023 3951 12037 3962 12045
      3970 12032
TIME...MOT...LOC 2242Z 240DEG 0KT 3958 12030 

HAIL...1.00IN
WIND...60MPH
 
$$

MB

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 21, 6:09 PM PDT	Areal Flood Advisory	REV	Lassen	2 hr
Jul 22, 12:59 PM PDT	Special Weather Statement	REV	Lassen, Plumas	3 hr
Jul 22, 2:08 PM PDT	Severe Thunderstorm Warning	REV	Lassen	37 min
Jul 22, 2:29 PM PDT	Areal Flood Advisory	REV	Plumas	2 hr
Jul 22, 2:44 PM PDT	Severe Thunderstorm Warning	REV	Plumas	31 min
Jul 22, 2:55 PM PDT	Severe Thunderstorm Warning	REV	Alpine	35 min
Jul 22, 2:56 PM PDT	Flash Flood Warning	REV	Sierra	3 hr
Jul 22, 3:14 PM PDT	Flash Flood Warning	REV	Plumas	3 hr
Jul 22, 3:24 PM PDT	Flash Flood Warning	REV	Lassen	3 hr
Jul 22, 3:50 PM PDT	Areal Flood Advisory	REV	Nevada, Sierra	3 hr
Jul 22, 3:58 PM PDT	Severe Thunderstorm Warning	REV	Nevada, Placer	32 min
Jul 22, 4:01 PM PDT	Severe Thunderstorm Warning	REV	Sierra	29 min
Jul 22, 4:31 PM PDT	Flash Flood Warning	REV	Nevada, Placer	116 min

Nearby

Severe Thunderstorm Warnings in California, 2020 Every severe thunderstorm warning in 2020

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.