Alert archive / California / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 5, NWS San Diego, CA

August 31, 2021San Diego County, California

NWS San Diego, CA issued this severe thunderstorm warning at Aug 31, 2021, 4:13 PM PDT for San Diego County, California. It was in force for 62 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 31, 2021, 4:13 PM PDT (23:13 UTC)
Expired
Aug 31, 2021, 5:15 PM PDT
In force
62 min
Issued by
NWS San Diego, CA
Area
Storm-based polygon
Hail
0.75 in
Wind
60.0 mph

County San Diego County, CA

The radar

The San Diego radar (KNKX), 74 km from the middle of the area, began a volume at 23:15 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, 11.2 hours before the alert went out and 93 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 2021-08-31Temperature 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 12:00Z on 2021-08-31The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -12 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
980 m above ground
0-6 km bulk shear
5 kt
0-1 km storm-relative helicity
-12 m²/s²
0-3 km storm-relative helicity
-16 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

534 
WUUS56 KSGX 312313
SVRSGX
CAC073-010015-
/O.NEW.KSGX.SV.W.0005.210831T2313Z-210901T0015Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service San Diego CA
413 PM PDT Tue Aug 31 2021

The National Weather Service in San Diego has issued a

* Severe Thunderstorm Warning for...
  East central San Diego County in southwestern California...

* Until 515 PM PDT.

* At 413 PM PDT, a severe thunderstorm was located near Hwy 78
  Between S2 And Borrego Springs Rd, moving northwest at 5 mph.

  HAZARD...60 mph wind gusts.

  SOURCE...Radar indicated.

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

* Locations impacted include...
  Borrego Springs, Hwy 78 Between Borrego Springs Rd And Ocotillo 
  Wells, Hwy S22 Between Ranchita And Borrego Springs and Fish Creek 
  Wash.

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 3305 11620 3300 11632 3324 11649 3331 11623
TIME...MOT...LOC 2313Z 153DEG 6KT 3310 11628 

HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...<.75 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH

$$

Gregoria
3 follow-up statements
218 
WWUS56 KSGX 312328
SVSSGX

Severe Weather Statement
National Weather Service San Diego CA
428 PM PDT Tue Aug 31 2021

CAC073-010015-
/O.CON.KSGX.SV.W.0005.000000T0000Z-210901T0015Z/
San Diego CA-
428 PM PDT Tue Aug 31 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 515 PM PDT
FOR EAST CENTRAL SAN DIEGO COUNTY...

At 428 PM PDT, a severe thunderstorm was located 7 miles southeast 
of Borrego Springs, moving northwest at 5 mph.

HAZARD...60 mph wind gusts.

SOURCE...Radar indicated.

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

Locations impacted include...
Borrego Springs, Hwy 78 Between S2 And Borrego Springs Rd, Hwy 78
Between Borrego Springs Rd And Ocotillo Wells, Hwy S22 Between
Ranchita And Borrego Springs and Fish Creek Wash.

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 3305 11620 3300 11632 3324 11649 3331 11623
TIME...MOT...LOC 2328Z 153DEG 6KT 3312 11629 

HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...<.75 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH

$$

Gregoria
525 
WWUS56 KSGX 312351
SVSSGX

Severe Weather Statement
National Weather Service San Diego CA
451 PM PDT Tue Aug 31 2021

CAC073-010015-
/O.CON.KSGX.SV.W.0005.000000T0000Z-210901T0015Z/
San Diego CA-
451 PM PDT Tue Aug 31 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 515 PM PDT
FOR EAST CENTRAL SAN DIEGO COUNTY...

At 448 PM PDT, a severe thunderstorm was located 11 miles southeast 
of Borrego Springs. This thunderstorms was nearly stationary and is 
no longer a risk for Borrego Springs.

HAZARD...60 mph wind gusts.

SOURCE...Radar indicated.

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

Locations impacted include...
Hwy 78 Between Borrego Springs Rd And Ocotillo Wells, Borrego 
Springs and Fish Creek Wash.

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 3305 11620 3300 11632 3313 11641 3320 11622
TIME...MOT...LOC 2348Z 271DEG 1KT 3308 11621 

HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...<.75 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH

$$

Gregoria
113 
WWUS56 KSGX 312353 CCA
SVSSGX

Severe Weather Statement
National Weather Service San Diego CA
453 PM PDT Tue Aug 31 2021

CAC073-010015-
/O.COR.KSGX.SV.W.0005.000000T0000Z-210901T0015Z/
San Diego CA-
453 PM PDT Tue Aug 31 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 515 PM PDT
FOR EAST CENTRAL SAN DIEGO COUNTY...

At 452 PM PDT, a severe thunderstorm was located 11 miles southeast 
of Borrego Springs. This thunderstorms was nearly stationary and is 
no longer a risk for Borrego Springs proper.

HAZARD...60 mph wind gusts.

SOURCE...Radar indicated.

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

Locations impacted include...
Hwy 78 Between Borrego Springs Rd And Ocotillo Wells and Fish Creek 
Wash.

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 3305 11620 3300 11632 3313 11641 3320 11622
TIME...MOT...LOC 2348Z 271DEG 1KT 3308 11621 

HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...<.75 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH

$$

Gregoria

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 30, 7:58 PM PDTSpecial Weather StatementSGXRiverside47 min
Aug 30, 8:18 PM PDTFlash Flood Warning Considerable damage threatSGXRiverside37 min
Aug 31, 3:30 PM PDTSpecial Weather StatementSGXSan Diego45 min
Aug 31, 4:55 PM PDTSpecial Weather StatementSGX65 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.