Alert archive / California / Severe Thunderstorm Warnings in 2021
Severe Thunderstorm Warning 6, NWS San Diego, CA
NWS San Diego, CA issued this severe thunderstorm warning at Aug 31, 2021, 5:17 PM PDT for Riverside County, San Diego County, California. It was in force for 58 min. 2 reports 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
- Aug 31, 2021, 5:17 PM PDT (00:17 UTC)
- Expired
- Aug 31, 2021, 6:15 PM PDT
- In force
- 58 min
- Issued by
- NWS San Diego, CA
- Area
- Storm-based polygon
- Hail
- 0.75 in
- Wind
- 60.0 mph
Counties Riverside County, CA, San Diego County, CA
The radar
The San Diego radar (KNKX), 109 km from the middle of the area, began a volume at 00:17 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
| Time | Report | Where | Remark |
|---|---|---|---|
| Aug 31, 5:30 PM PDT | TSTM WND DMG | Mecca, CA | STRONG THUNDERSTORM WINDS RESULTED IN ROOF DAMAGE AT THE GALILEE CENTER, USED AS A SHELTER FOR PEOPLE WHO HAD LOST POWER THE DAY BEFORE. THE LEAKING ROOF PROMPTED EVACUATION OF THE BUILDING. |
| Aug 31, 5:32 PM PDT | TSTM WND GST 34 | Mecca, CA | MESONET STATION UP633 MECCA. |
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 00:00Z, 0.3 hours before the alert went out and 129 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.
- Mixed-layer CAPE
- 0 J/kg
- Mixed-layer CIN
- No buoyant parcel
- Mixed-layer LCL
- 853 m above ground
- 0-6 km bulk shear
- 15 kt
- 0-1 km storm-relative helicity
- -77 m²/s²
- 0-3 km storm-relative helicity
- -65 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
882
WUUS56 KSGX 010017
SVRSGX
CAC065-073-010115-
/O.NEW.KSGX.SV.W.0006.210901T0017Z-210901T0115Z/
BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service San Diego CA
517 PM PDT Tue Aug 31 2021
The National Weather Service in San Diego has issued a
* Severe Thunderstorm Warning for...
Riverside County in southern California...
Northeastern San Diego County in southwestern California...
* Until 615 PM PDT.
* At 516 PM PDT, a severe thunderstorm was located 3 miles west of
Desert Shores, or 13 miles northwest of Salton City, and is nearly
stationary.
HAZARD...60 mph wind gusts.
SOURCE...Radar indicated.
IMPACT...Expect damage to roofs, siding, and trees.
* Locations impacted include...
Hwy S22 Between Borrego Springs And Imperial County Line, Thermal,
Mecca and Santa Rosa Mountain.
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 3352 11605 3351 11605 3351 11607 3350 11608
3345 11604 3343 11603 3342 11609 3328 11608
3328 11632 3361 11624 3360 11595 3352 11595
TIME...MOT...LOC 0016Z 109DEG 1KT 3338 11613
HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...<.75 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH
$$
Gregoria1 follow-up statement
516
WWUS56 KSGX 010109
SVSSGX
Severe Weather Statement
National Weather Service San Diego CA
609 PM PDT Tue Aug 31 2021
CAC065-073-010117-
/O.EXP.KSGX.SV.W.0006.000000T0000Z-210901T0115Z/
Riverside CA-San Diego CA-
609 PM PDT Tue Aug 31 2021
...THE SEVERE THUNDERSTORM WARNING FOR RIVERSIDE AND NORTHEASTERN SAN
DIEGO COUNTIES WILL EXPIRE AT 615 PM PDT...
The storm which prompted the warning has weakened below severe
limits. Therefore, the Severe Thunderstorms Warning will be allowed
to expire. However, heavy rain is still occurring and water is
likely flowing in normally dry washes. A Flash Flood Warning is in
effect for this area until 845 PM.
LAT...LON 3352 11605 3351 11605 3351 11607 3350 11608
3345 11604 3343 11603 3342 11609 3328 11608
3328 11632 3361 11624 3360 11595 3352 11595
TIME...MOT...LOC 0107Z 109DEG 1KT 3338 11614
$$
GregoriaThe office that day
Everything else NWS San Diego, CA issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 31, 5:44 PM PDT | Flash Flood Warning | SGX | Riverside, San Diego | 96 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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.