Alert archive / California / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 74, NWS Las Vegas, NV

September 24, 2021San Bernardino County, California

NWS Las Vegas, NV issued this severe thunderstorm warning at Sep 24, 2021, 2:11 PM PDT for San Bernardino County, California. It was in force for 49 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
Sep 24, 2021, 2:11 PM PDT (21:11 UTC)
Expired
Sep 24, 2021, 3:00 PM PDT
In force
49 min
Issued by
NWS Las Vegas, NV
Area
Storm-based polygon
Hail
1.0 in
Wind
60.0 mph

County San Bernardino County, CA

The radar

The Santa Ana Mts radar (KSOX), 120 km from the middle of the area, began a volume at 21:13 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.

What was reported inside it

TimeReportWhereRemark
Sep 24, 2:15 PM PDTHAIL 11 Sw Yucca Valley, CAPUBLIC REPORTED A MIX OF QUARTER AND NICKEL SIZE HAIL. VIDEO SUPPORTED CLAIM. TIME ESTIMATED BY RADAR.

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

The nearest sounding before it

San Diego, CA (KNKX), launched 12:00Z, 9.2 hours before the alert went out and 166 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 12:00Z on 2021-09-24Temperature 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 12:00Z on 2021-09-24The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -36 square meters per square second.1939587897Sfc1 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
1990 m above ground
0-6 km bulk shear
4 kt
0-1 km storm-relative helicity
-36 m²/s²
0-3 km storm-relative helicity
15 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

848 
WUUS55 KVEF 242111
SVRVEF
CAC071-242200-
/O.NEW.KVEF.SV.W.0074.210924T2111Z-210924T2200Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Las Vegas NV
211 PM PDT Fri Sep 24 2021

The National Weather Service in Las Vegas has issued a

* Severe Thunderstorm Warning for...
  South central San Bernardino County in southern California...

* Until 300 PM PDT.

* At 211 PM PDT, a severe thunderstorm was located over Yucca Valley,
  or 18 miles east of Onyx Summit, moving north at 10 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 and trees.

* Locations impacted include...
  Yucca Valley, Joshua Tree and Joshua Tree Lake Campground. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3406 11656 3411 11656 3414 11647 3421 11644
      3427 11644 3426 11622 3414 11620 3412 11622
      3412 11626 3408 11627 3408 11644 3404 11647
TIME...MOT...LOC 2111Z 188DEG 10KT 3414 11640 

HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...1.00 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH

$$
Outler
2 follow-up statements
542 
WWUS55 KVEF 242131
SVSVEF

Severe Weather Statement
National Weather Service Las Vegas NV
231 PM PDT Fri Sep 24 2021

CAC071-242200-
/O.CON.KVEF.SV.W.0074.000000T0000Z-210924T2200Z/
San Bernardino CA-
231 PM PDT Fri Sep 24 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 300 PM PDT
FOR SOUTHWESTERN SAN BERNARDINO COUNTY...

At 231 PM PDT, a severe thunderstorm was located near Yucca Valley, 
or 18 miles east of Onyx Summit, moving west at 10 mph.  Hail to 
near quarter size has been reported in Yucca Valley with this storm.

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

SOURCE...Radar indicated.

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

This severe thunderstorm will remain over mainly rural areas of
southwestern San Bernardino County.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3406 11656 3411 11656 3414 11647 3408 11644
      3404 11647
TIME...MOT...LOC 2131Z 188DEG 10KT 3420 11639 

HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...1.00 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH

$$

Outler
170 
WWUS55 KVEF 242152
SVSVEF

Severe Weather Statement
National Weather Service Las Vegas NV
252 PM PDT Fri Sep 24 2021

CAC071-242201-
/O.EXP.KVEF.SV.W.0074.000000T0000Z-210924T2200Z/
San Bernardino CA-
252 PM PDT Fri Sep 24 2021

...THE SEVERE THUNDERSTORM WARNING FOR SOUTHWESTERN SAN BERNARDINO
COUNTY WILL EXPIRE AT 300 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.

LAT...LON 3406 11656 3411 11656 3414 11647 3408 11644
      3404 11647
TIME...MOT...LOC 2151Z 188DEG 10KT 3425 11638 

$$

Outler

The office that day

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

IssuedProductOfficeCountiesLasted
Sep 24, 1:49 PM PDTAreal Flood AdvisoryVEFSan Bernardino3 hr
Sep 24, 2:18 PM PDTAreal Flood AdvisoryVEFSan Bernardino3 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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.