Alert archive / California / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 5, NWS Phoenix, AZ

June 23, 2021Riverside County, California

NWS Phoenix, AZ issued this severe thunderstorm warning at Jun 23, 2021, 5:38 PM PDT for Riverside County, California. It was in force for 37 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: Jun 23, 2021, 5:38 PM PDT (00:38 UTC)
Expired: Jun 23, 2021, 6:15 PM PDT
In force: 37 min
Issued by: NWS Phoenix, AZ
Area: Storm-based polygon
Hail: 0.88 in
Wind: 60.0 mph

County Riverside County, CA

The radar

The Yuma radar (KYUX), 126 km from the middle of the area, began a volume at 00:39 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
Jun 23, 5:45 PM PDT	TSTM WND DMG	18 Ese Desert Center, CA	SEMI-TRUCK BLOWN OVER ON I-10.

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

The nearest sounding before it

Yuma Prvg Ground, AZ (K1Y7), launched 00:00Z, 0.6 hours before the alert went out and 134 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: 433 J/kg
Mixed-layer CIN: -16 J/kg
Mixed-layer LCL: 2844 m above ground
0-6 km bulk shear: 25 kt
0-1 km storm-relative helicity: 19 m²/s²
0-3 km storm-relative helicity: -10 m²/s²
Significant tornado parameter: 0.0
Supercell composite: -0.1

Open this sounding in Storm Lab

The text

As transmitted.

107 
WUUS55 KPSR 240038
SVRPSR
CAC065-240115-
/O.NEW.KPSR.SV.W.0005.210624T0038Z-210624T0115Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Phoenix AZ
538 PM PDT Wed Jun 23 2021

The National Weather Service in Phoenix has issued a

* Severe Thunderstorm Warning for...
  Riverside County in southern California...

* Until 615 PM PDT.

* At 538 PM PDT, a severe thunderstorm was located 16 miles east of
  Desert Center, moving northeast at 5 mph.

  HAZARD...60 mph wind gusts and nickel size hail.

  SOURCE...Radar indicated.

  IMPACT...Expect damage to roofs, siding, and trees.

* This severe thunderstorm will remain over mainly rural areas of
  Riverside County.
  * This includes CA Interstate 10 between mile markers 115 and 139.
 
PRECAUTIONARY/PREPAREDNESS ACTIONS...

For your protection move to an interior room on the lowest floor of a
building.

Large hail and damaging winds and continuous cloud to ground
lightning is occurring with this storm. Move indoors immediately.
Lightning is one of nature's leading killers. Remember, if you can
hear thunder, you are close enough to be struck by lightning.

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

&&

LAT...LON 3348 11495 3346 11511 3362 11530 3382 11513
      3363 11481
TIME...MOT...LOC 0038Z 224DEG 5KT 3363 11514 

HAIL...0.88IN
WIND...60MPH
 
$$

SDB

2 follow-up statements

306 
WWUS55 KPSR 240103
SVSPSR

Severe Weather Statement
National Weather Service Phoenix AZ
603 PM PDT Wed Jun 23 2021

CAC065-240115-
/O.CON.KPSR.SV.W.0005.000000T0000Z-210624T0115Z/
Riverside CA-
603 PM PDT Wed Jun 23 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 615 PM PDT
FOR RIVERSIDE COUNTY...

At 558 PM PDT, a severe thunderstorm was located 15 miles west of
Nicholls Warm Springs, or 26 miles southeast of Desert Center, 
moving northeast at 10 mph. CHP reported an overturned semi on I-10 
east of Desert Center due to strong winds.

HAZARD...60 mph wind gusts and nickel size hail.

SOURCE...Emergency management.

IMPACT...Expect damage to roofs, siding, and trees.

This severe thunderstorm will remain over mainly rural areas of
Riverside County.
This includes CA Interstate 10 between mile markers 120 and 139.
 
PRECAUTIONARY/PREPAREDNESS ACTIONS...

For your protection move to an interior room on the lowest floor of a
building.

To report severe weather contact your nearest law enforcement agency.
They will send your report to the National Weather Service office in
Phoenix.

Continuous cloud to ground lightning is occurring with this storm.
Move indoors immediately. Lightning is one of nature's leading
killers. Remember, if you can hear thunder, you are close enough to
be struck by lightning.

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

&&

LAT...LON 3348 11495 3346 11511 3365 11516 3378 11506
      3363 11481
TIME...MOT...LOC 0058Z 247DEG 11KT 3356 11499 

HAIL...0.88IN
WIND...60MPH
 
$$

SDB

539 
WWUS55 KPSR 240112
SVSPSR

Severe Weather Statement
National Weather Service Phoenix AZ
612 PM PDT Wed Jun 23 2021

CAC065-240122-
/O.EXP.KPSR.SV.W.0005.000000T0000Z-210624T0115Z/
Riverside CA-
612 PM PDT Wed Jun 23 2021

...THE SEVERE THUNDERSTORM WARNING FOR RIVERSIDE COUNTY WILL EXPIRE
AT 615 PM PDT...
                
The storm which prompted the warning has weakened below severe
limits, and no longer poses an immediate threat to life or property.
Therefore, the warning will be allowed to expire.  However gusty
winds and heavy rain are still possible with this thunderstorm.

To report severe weather, contact your nearest law enforcement
agency. They will relay your report to the National Weather Service
Phoenix.

LAT...LON 3348 11495 3346 11511 3365 11516 3378 11506
      3363 11481
TIME...MOT...LOC 0112Z 224DEG 5KT 3357 11497 

$$

SDB

The office that day

Everything else NWS Phoenix, AZ issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Jun 23, 5:33 PM PDT	Flash Flood Warning Considerable damage threat	PSR	Riverside	2 hr
Jun 23, 6:10 PM PDT	Special Weather Statement	PSR	Imperial	50 min
Jun 23, 6:28 PM PDT	Areal Flood Advisory	PSR	Riverside	3 hr
Jun 23, 7:16 PM PDT	Flash Flood Warning Considerable damage threat	PSR	Riverside	4 hr

Nearby

Severe Thunderstorm Warnings in California, 2021 Every severe thunderstorm 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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.