Alert archive / California / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 41, NWS Phoenix, AZ

July 30, 2021Riverside County, California

NWS Phoenix, AZ issued this severe thunderstorm warning at Jul 30, 2021, 6:11 PM PDT for Riverside County, California. It was in force for 79 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 30, 2021, 6:11 PM PDT (01:11 UTC)
Expired
Jul 30, 2021, 7:30 PM PDT
In force
79 min
Issued by
NWS Phoenix, AZ
Area
Storm-based polygon
Hail
1.0 in
Wind
60.0 mph

County Riverside County, CA

The radar

The San Diego radar (KNKX), 156 km from the middle of the area, began a volume at 01:13 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

San Diego, CA (KNKX), launched 00:00Z, 1.2 hours before the alert went out and 175 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, San Diego, CA at 00:00Z on 2021-07-31Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 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, San Diego, CA at 00:00Z on 2021-07-31The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -18 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
2564 m above ground
0-6 km bulk shear
10 kt
0-1 km storm-relative helicity
-18 m²/s²
0-3 km storm-relative helicity
33 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

868 
WUUS55 KPSR 310111
SVRPSR
CAC065-310230-
/O.NEW.KPSR.SV.W.0041.210731T0111Z-210731T0230Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Phoenix AZ
611 PM PDT Fri Jul 30 2021

The National Weather Service in Phoenix has issued a

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

* Until 730 PM PDT.

* At 611 PM PDT, a severe thunderstorm was located near Chiriaco
  Summit, moving southeast at 15 mph.

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

  SOURCE...Radar indicated.

  IMPACT...Hail damage to vehicles is expected. Expect wind damage 
           to roofs, siding, and trees.

* Locations impacted include...
  Desert Center and Chiriaco Summit. 

* This includes the following highways...
  CA Interstate 10 between mile markers 81 and 112.
  CA Route 177 between mile markers 1 and 5.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

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

&&

LAT...LON 3362 11583 3384 11575 3375 11524 3343 11542
TIME...MOT...LOC 0111Z 293DEG 13KT 3367 11565 

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

Hirsch
2 follow-up statements
401 
WWUS55 KPSR 310134
SVSPSR

Severe Weather Statement
National Weather Service Phoenix AZ
634 PM PDT Fri Jul 30 2021

CAC065-310230-
/O.CON.KPSR.SV.W.0041.000000T0000Z-210731T0230Z/
Riverside CA-
634 PM PDT Fri Jul 30 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 730 PM PDT
FOR RIVERSIDE COUNTY...

At 634 PM PDT, a severe thunderstorm was located 8 miles east of
Chiriaco Summit, moving southeast at 15 mph.

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

SOURCE...Radar indicated.

IMPACT...Hail damage to vehicles is expected. Expect wind damage to 
         roofs, siding, and trees.

Locations impacted include...
Desert Center and Chiriaco Summit. 

This includes the following highways...
CA Interstate 10 between mile markers 81 and 112.
CA Route 177 between mile markers 1 and 5.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

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

&&

LAT...LON 3362 11583 3384 11575 3375 11524 3343 11542
TIME...MOT...LOC 0134Z 293DEG 13KT 3364 11557 

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

Hirsch
173 
WWUS55 KPSR 310226
SVSPSR

Severe Weather Statement
National Weather Service Phoenix AZ
726 PM PDT Fri Jul 30 2021

CAC065-310235-
/O.EXP.KPSR.SV.W.0041.000000T0000Z-210731T0230Z/
Riverside CA-
726 PM PDT Fri Jul 30 2021

...THE SEVERE THUNDERSTORM WARNING FOR RIVERSIDE COUNTY WILL EXPIRE
AT 730 PM PDT...
        
The storm which prompted the warning has weakened below severe
limits, and has exited the warned area. Therefore, the warning will
be allowed to expire.

LAT...LON 3362 11583 3384 11575 3375 11524 3343 11542
TIME...MOT...LOC 0225Z 293DEG 13KT 3357 11537 

$$

Hirsch

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 30, 5:04 PM PDTDust Storm AdvisoryPSRImperial41 min
Jul 30, 5:18 PM PDTSpecial Weather StatementPSRImperial72 min
Jul 30, 5:20 PM PDTSpecial Weather StatementPSRRiverside70 min
Jul 30, 5:24 PM PDTFlash Flood Warning Considerable damage threatPSRRiverside4 hr
Jul 30, 5:29 PM PDTSevere Thunderstorm WarningPSRImperial46 min
Jul 30, 5:33 PM PDTFlash Flood Warning Considerable damage threatPSRImperial4 hr
Jul 30, 5:39 PM PDTAreal Flood AdvisoryPSRImperial3 hr
Jul 30, 5:52 PM PDTFlash Flood Warning Considerable damage threatPSRRiverside4 hr
Jul 30, 5:59 PM PDTDust Storm WarningPSRImperial45 min
Jul 30, 6:06 PM PDTFlash Flood Warning Considerable damage threatPSRImperial4 hr
Jul 30, 6:31 PM PDTSpecial Weather StatementPSRImperial74 min
Jul 30, 6:49 PM PDTFlash Flood Warning Considerable damage threatPSRImperial, Riverside4 hr
Jul 31, 2:32 PM PDTSpecial Weather StatementPSRRiverside28 min
Jul 31, 3:47 PM PDTSpecial Weather StatementPSRRiverside28 min
Jul 31, 4:48 PM PDTFlash Flood Warning Considerable damage threatPSRRiverside3 hr

Nearby

Severe Thunderstorm Warnings in California, 2021Every 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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.