Alert archive / California / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 64, NWS Las Vegas, NV

August 13, 2021San Bernardino County, California

NWS Las Vegas, NV issued this severe thunderstorm warning at Aug 13, 2021, 4:55 PM PDT for San Bernardino County, California. It was in force for 50 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
Aug 13, 2021, 4:55 PM PDT (23:55 UTC)
Expired
Aug 13, 2021, 5:45 PM PDT
In force
50 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 Las Vegas radar (KESX), 111 km from the middle of the area, began a volume at 23:55 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

Las Vegas, NV (KVEF), launched 12:00Z, 11.9 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, Las Vegas, NV at 12:00Z on 2021-08-13Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 487 joules per kilogram.LCLLFCEL10008507005003002001001 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, Las Vegas, NV at 12:00Z on 2021-08-13The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -8 square meters per square second.1939Sfc1 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
487 J/kg
Mixed-layer CIN
-323 J/kg
Mixed-layer LCL
2453 m above ground
0-6 km bulk shear
11 kt
0-1 km storm-relative helicity
-8 m²/s²
0-3 km storm-relative helicity
80 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.1

Open this sounding in Storm Lab

The text

As transmitted.

737 
WUUS55 KVEF 132355
SVRVEF
CAC071-140045-
/O.NEW.KVEF.SV.W.0064.210813T2355Z-210814T0045Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Las Vegas NV
455 PM PDT Fri Aug 13 2021

The National Weather Service in Las Vegas has issued a

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

* Until 545 PM PDT.

* At 454 PM PDT, a severe thunderstorm was located 11 miles south of
  Mitchell Caverns, moving south at 65 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...
  Mitchell Caverns, Kelso, Amboy, Hole In The Wall Campground, Mid
  Hills Campground, Essex and Black Canyon Equestrian Campground.

This includes Interstate 40 in California between mile markers 60 and
115.
 
PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3516 11586 3520 11522 3469 11499 3450 11557
      3460 11602
TIME...MOT...LOC 2354Z 356DEG 56KT 3478 11554 

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

$$

DSB
2 follow-up statements
002 
WWUS55 KVEF 140014
SVSVEF

Severe Weather Statement
National Weather Service Las Vegas NV
514 PM PDT Fri Aug 13 2021

CAC071-140045-
/O.CON.KVEF.SV.W.0064.000000T0000Z-210814T0045Z/
San Bernardino CA-
514 PM PDT Fri Aug 13 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 545 PM PDT
FOR CENTRAL SAN BERNARDINO COUNTY...

At 513 PM PDT, a severe thunderstorm was located 14 miles southeast
of Amboy, or 31 miles south of Mitchell Caverns, moving south at 65
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...
Mitchell Caverns, Kelso, Amboy, Hole In The Wall Campground, Mid
Hills Campground, Essex and Black Canyon Equestrian Campground.

This includes Interstate 40 in California between mile markers 60 and
115.
 
PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3516 11586 3520 11522 3469 11499 3450 11557
      3460 11602
TIME...MOT...LOC 0013Z 356DEG 56KT 3448 11551 

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

$$

DSB
427 
WWUS55 KVEF 140041
SVSVEF

Severe Weather Statement
National Weather Service Las Vegas NV
541 PM PDT Fri Aug 13 2021

CAC071-140051-
/O.EXP.KVEF.SV.W.0064.000000T0000Z-210814T0045Z/
San Bernardino CA-
541 PM PDT Fri Aug 13 2021

...THE SEVERE THUNDERSTORM WARNING FOR CENTRAL SAN BERNARDINO COUNTY
WILL EXPIRE AT 545 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 3516 11586 3520 11522 3469 11499 3450 11557
      3460 11602
TIME...MOT...LOC 0041Z 356DEG 56KT 3410 11548 

$$

DSB

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 13, 2:37 AM PDTExcessive Heat WatchVEFInyo, San Bernardino12 hr
Aug 13, 2:18 PM PDTExcessive Heat WarningVEFInyo, San Bernardino3 days
Aug 13, 2:23 PM PDTSevere Thunderstorm WarningVEFSan Bernardino52 min
Aug 13, 2:46 PM PDTFlash Flood Warning Considerable damage threatVEFSan Bernardino3 hr
Aug 13, 3:20 PM PDTSevere Thunderstorm WarningVEFSan Bernardino40 min
Aug 13, 4:04 PM PDTSevere Thunderstorm WarningVEFSan Bernardino41 min

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.