Alert archive / California / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 8, NWS San Diego, CA

September 9, 2021San Bernardino County, California

NWS San Diego, CA issued this severe thunderstorm warning at Sep 9, 2021, 1:19 PM PDT for San Bernardino County, California. It was in force for 22 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
Sep 9, 2021, 1:19 PM PDT (20:19 UTC)
Expired
Sep 9, 2021, 1:41 PM PDT
In force
22 min
Issued by
NWS San Diego, CA
Area
Storm-based polygon
Damage threat
Considerable
Hail
0.75 in
Wind
70.0 mph

County San Bernardino County, CA

The radar

The Edwards AFB radar (KEYX), 58 km from the middle of the area, began a volume at 20:21 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 12:00Z, 8.3 hours before the alert went out and 216 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 2021-09-09Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 15 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, San Diego, CA at 12:00Z on 2021-09-09The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 44 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
15 J/kg
Mixed-layer CIN
-787 J/kg
Mixed-layer LCL
1710 m above ground
0-6 km bulk shear
28 kt
0-1 km storm-relative helicity
44 m²/s²
0-3 km storm-relative helicity
112 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.1

Open this sounding in Storm Lab

The text

As transmitted.

825 
WUUS56 KSGX 092019
SVRSGX
CAC071-092100-
/O.NEW.KSGX.SV.W.0008.210909T2019Z-210909T2100Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service San Diego CA
119 PM PDT Thu Sep 9 2021

The National Weather Service in San Diego has issued a

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

* Until 200 PM PDT.

* At 119 PM PDT, a severe thunderstorm was located over I-15 Between
  Victorville And Barstow, moving north at 20 mph.

  HAZARD...70 mph wind gusts and penny size hail.

  SOURCE...Radar indicated.

  IMPACT...Expect considerable tree damage. Damage is likely to 
           mobile homes, roofs, and outbuildings.

* Locations impacted include...
  Apple Valley, I-15 Between Victorville And Barstow, Hwy 247 Between
  Lucerne Valley And Barstow and Helendale.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3478 11703 3478 11702 3465 11701 3463 11722
      3480 11729
TIME...MOT...LOC 2019Z 169DEG 16KT 3472 11714 

THUNDERSTORM DAMAGE THREAT...CONSIDERABLE
HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...0.75 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...70 MPH

$$

JMB
1 follow-up statement
710 
WWUS56 KSGX 092041
SVSSGX

Severe Weather Statement
National Weather Service San Diego CA
141 PM PDT Thu Sep 9 2021

CAC071-092051-
/O.CAN.KSGX.SV.W.0008.000000T0000Z-210909T2100Z/
San Bernardino CA-
141 PM PDT Thu Sep 9 2021

...THE SEVERE THUNDERSTORM WARNING FOR SAN BERNARDINO COUNTY IS
CANCELLED...
        
The storm which prompted the warning has moved out of the area.
Therefore, the warning has been cancelled.

LAT...LON 3478 11703 3478 11702 3465 11701 3463 11722
      3480 11729
TIME...MOT...LOC 2036Z 169DEG 16KT 3482 11716 

$$

JMB

The office that day

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

IssuedProductOfficeCountiesLasted
Sep 9, 12:40 PM PDTSpecial Weather StatementSGX50 min
Sep 9, 1:05 PM PDTSevere Thunderstorm WarningSGXSan Bernardino40 min
Sep 9, 2:12 PM PDTAreal Flood AdvisorySGXSan Diego3 hr
Sep 9, 2:34 PM PDTFlash Flood Warning Considerable damage threatSGXSan Bernardino3 hr
Sep 9, 2:54 PM PDTSevere Thunderstorm WarningSGXSan Bernardino66 min
Sep 9, 3:10 PM PDTSevere Thunderstorm WarningSGXRiverside, San Bernardino50 min
Sep 9, 3:25 PM PDTSpecial Weather StatementSGX50 min
Sep 9, 3:29 PM PDTFlash Flood Warning Considerable damage threatSGXRiverside, San Bernardino2 hr
Sep 9, 3:46 PM PDTAreal Flood AdvisorySGXRiverside3 hr
Sep 9, 4:33 PM PDTFlash Flood Warning Considerable damage threatSGXRiverside88 min
Sep 9, 4:35 PM PDTSevere Thunderstorm WarningSGXRiverside, San Bernardino55 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.