Alert archive / California / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 11, NWS San Diego, CA

September 9, 2021Riverside County, San Bernardino County, California

NWS San Diego, CA issued this severe thunderstorm warning at Sep 9, 2021, 4:35 PM PDT for Riverside County, San Bernardino County, California. It was in force for 55 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, 4:35 PM PDT (23:35 UTC)
Expired
Sep 9, 2021, 5:30 PM PDT
In force
55 min
Issued by
NWS San Diego, CA
Area
Storm-based polygon
Hail
0.88 in
Wind
60.0 mph

Counties Riverside County, CA, San Bernardino County, CA

The radar

The Santa Ana Mts radar (KSOX), 59 km from the middle of the area, began a volume at 23:35 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, 11.6 hours before the alert went out and 130 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.

960 
WUUS56 KSGX 092335
SVRSGX
CAC065-071-100030-
/O.NEW.KSGX.SV.W.0011.210909T2335Z-210910T0030Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service San Diego CA
435 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...
  Riverside County in southern California...

* Until 530 PM PDT.

* At 434 PM PDT, a severe thunderstorm was located near Beaumont, or
  7 miles south of Yucaipa, moving northwest at 20 mph.

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

  SOURCE...Radar indicated.

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

* Locations impacted include...
  Moreno Valley, Redlands, Yucaipa, Highland, Colton, Beaumont,
  Banning, Loma Linda, Mentone and Calimesa.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3391 11688 3384 11695 3399 11726 3414 11712
TIME...MOT...LOC 2334Z 126DEG 17KT 3393 11702 

HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...0.88 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH

$$

Moreland
2 follow-up statements
011 
WWUS56 KSGX 100000
SVSSGX

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

CAC065-071-100030-
/O.CON.KSGX.SV.W.0011.000000T0000Z-210910T0030Z/
San Bernardino CA-Riverside CA-
500 PM PDT Thu Sep 9 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 530 PM PDT
FOR SAN BERNARDINO AND RIVERSIDE COUNTIES...

At 459 PM PDT, a severe thunderstorm was located over Redlands,
moving northwest at 20 mph.

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

SOURCE...Radar indicated.

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

Locations impacted include...
Moreno Valley, Redlands, Yucaipa, Highland, Colton, western Beaumont,
Loma Linda, Mentone, Calimesa and Cherry Valley.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3399 11697 3389 11706 3399 11726 3414 11712
TIME...MOT...LOC 2359Z 126DEG 17KT 3401 11715 

HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...0.88 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH

$$

Moreland
435 
WWUS56 KSGX 100030
SVSSGX

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

CAC065-071-100040-
/O.EXP.KSGX.SV.W.0011.000000T0000Z-210910T0030Z/
San Bernardino CA-Riverside CA-
530 PM PDT Thu Sep 9 2021

...THE SEVERE THUNDERSTORM WARNING FOR SAN BERNARDINO AND RIVERSIDE
COUNTIES HAS EXPIRED...
        
The storm which prompted the warning has weakened below severe
limits, and has exited the warned area. Therefore, the warning has
been allowed to expire.

LAT...LON 3399 11697 3389 11706 3399 11726 3414 11712
TIME...MOT...LOC 0030Z 126DEG 17KT 3408 11726 

$$

Moreland

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, 1:19 PM PDTSevere Thunderstorm Warning Considerable damage threatSGXSan Bernardino22 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

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.