Alert archive / California / Tornado Warnings in 2021

Tornado Warning 1, NWS Sacramento, CA

January 4, 2021Tehama County, California

NWS Sacramento, CA issued this tornado warning at Jan 4, 2021, 2:38 PM PST for Tehama County, California. It was in force for 21 min. 1 report came from inside the area while it was in force.

The area

The outline as issued, with what was reported inside it.

The facts

Issued: Jan 4, 2021, 2:38 PM PST (22:38 UTC)
Expired: Jan 4, 2021, 2:59 PM PST
In force: 21 min
Issued by: NWS Sacramento, CA
Area: Storm-based polygon
Tornado: Radar indicated
Hail: 0.75 in

County Tehama County, CA

The radar

The Beale AFB radar (KBBX), 61 km from the middle of the area, began a volume at 22:39 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.

What was reported inside it

Time	Report	Where	Remark
Jan 4, 2:40 PM PST	TORNADO	4 Ne Vina, CA	A TORNADO WAS SITED ON THE GROUND OUT IN AN OPEN FIELD NEAR VINA BY CALFIRE. NO DAMAGE HAS BEEN REPORTED. MULTIPLE PHOTOS AND VIDEOS CONFIRM A TORNADO IN CLEAR CONTACT WITH THE GROUND.

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The nearest sounding before it

Oakland, CA (KOAK), launched 12:00Z, 10.6 hours before the alert went out and 252 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: 0 J/kg
Mixed-layer CIN: No buoyant parcel
Mixed-layer LCL: 890 m above ground
0-6 km bulk shear: 60 kt
0-1 km storm-relative helicity: 182 m²/s²
0-3 km storm-relative helicity: 243 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

293 
WFUS56 KSTO 042238
TORSTO
CAC103-042315-
/O.NEW.KSTO.TO.W.0001.210104T2238Z-210104T2315Z/

BULLETIN - EAS ACTIVATION REQUESTED
Tornado Warning
National Weather Service Sacramento CA
238 PM PST Mon Jan 4 2021

The National Weather Service in Sacramento has issued a

* Tornado Warning for...
  South central Tehama County in northern California...

* Until 315 PM PST.
    
* At 238 PM PST, a severe thunderstorm capable of producing a tornado
  was located near Vina, or 11 miles east of Corning, moving
  northeast at 30 mph.

  HAZARD...Tornado.

  SOURCE...Radar indicated rotation.

  IMPACT...Flying debris will be dangerous to those caught without 
           shelter. Mobile homes will be damaged or destroyed. 
           Damage to roofs, windows, and vehicles will occur.  Tree 
           damage is likely.

* This tornadic thunderstorm will remain over mainly rural areas of
  south central Tehama County.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

TAKE COVER NOW! Move to an interior room on the lowest floor of a
sturdy building. Avoid windows. If you are outdoors, in a mobile
home, or in a vehicle, move to the closest substantial shelter and
protect yourself from flying debris.

&&

LAT...LON 3991 12203 4005 12203 4015 12178 3993 12179
TIME...MOT...LOC 2238Z 230DEG 25KT 3998 12197 

TORNADO...RADAR INDICATED
HAIL...<.75IN

$$

CM

1 follow-up statement

179 
WWUS56 KSTO 042259
SVSSTO

Severe Weather Statement
National Weather Service Sacramento CA
259 PM PST Mon Jan 4 2021

CAC103-042307-
/O.CAN.KSTO.TO.W.0001.000000T0000Z-210104T2315Z/
Tehama CA-
259 PM PST Mon Jan 4 2021

...THE TORNADO WARNING FOR SOUTH CENTRAL TEHAMA COUNTY IS
CANCELLED...
                
The storm which prompted the warning has weakened below severe
limits, and no longer appears capable of producing a tornado.
Therefore, the warning has been cancelled.

LAT...LON 3991 12203 4005 12203 4015 12178 3993 12179
TIME...MOT...LOC 2256Z 230DEG 25KT 4007 12183 

$$

CM

The office that day

Everything else NWS Sacramento, CA issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Jan 4, 2:38 AM PST	Flash Flood Watch	STO		15 hr
Jan 4, 1:30 PM PST	Special Weather Statement	STO	Tehama	45 min
Jan 4, 1:34 PM PST	Special Weather Statement	STO	Shasta	41 min
Jan 4, 2:28 PM PST	Special Weather Statement	STO	Tehama	47 min
Jan 4, 3:35 PM PST	Tornado Warning	STO	Butte, Tehama	25 min

Nearby

Tornado Warnings in California, 2021 Every tornado warning in 2021 Tornadoes 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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.