Alert archive / California / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 14, NWS San Diego, CA

September 24, 2021San Diego County, California

NWS San Diego, CA issued this severe thunderstorm warning at Sep 24, 2021, 2:41 PM PDT for San Diego County, California. It was in force for 64 min. 3 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: Sep 24, 2021, 2:41 PM PDT (21:41 UTC)
Expired: Sep 24, 2021, 3:45 PM PDT
In force: 64 min
Issued by: NWS San Diego, CA
Area: Storm-based polygon
Hail: 1.0 in
Wind: 60.0 mph

County San Diego County, CA

The radar

The San Diego radar (KNKX), 39 km from the middle of the area, began a volume at 21:42 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
Sep 24, 2:50 PM PDT	TSTM WND GST 50	3 Sse Harbison Canyon, CA	SEQUAN TRUCK TRAIL SDGE MESONET.
Sep 24, 3:20 PM PDT	TSTM WND DMG	1 S Alpine, CA	LARGE TREE DOWN AND ON ROADWAY AT OAK VIEW PL AND SCENIC VIEW ROAD. CHAIN SAW REQUIRED.
Sep 24, 3:23 PM PDT	TSTM WND DMG	1 Ssw Alpine, CA	LARGE TREE ON VEHICLE AT OAK VIEW PLACE AND SCENIC VIEW ROAD.

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 12:00Z, 9.7 hours before the alert went out and 51 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 1990 m above ground
0-6 km bulk shear: 4 kt
0-1 km storm-relative helicity: -36 m²/s²
0-3 km storm-relative helicity: 15 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

490 
WUUS56 KSGX 242141
SVRSGX
CAC073-242245-
/O.NEW.KSGX.SV.W.0014.210924T2141Z-210924T2245Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service San Diego CA
241 PM PDT Fri Sep 24 2021

The National Weather Service in San Diego has issued a

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

* Until 345 PM PDT.

* At 238 PM PDT, a line of severe thunderstorms extended from Alpine 
  to Potrero, moving west at 25 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, siding, and trees.

* Locations impacted include...
  Alpine, Cuyamaca Rancho State Park, Lake Morena, Potrero, 
  Descanso, Campo, Crest, Pine Valley and Lakeside.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3292 11656 3261 11646 3257 11680 3293 11689
TIME...MOT...LOC 2138Z 097DEG 28KT 3276 11681 

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

$$

Maxwell

1 follow-up statement

226 
WWUS56 KSGX 242241
SVSSGX

Severe Weather Statement
National Weather Service San Diego CA
341 PM PDT Fri Sep 24 2021

CAC073-242250-
/O.EXP.KSGX.SV.W.0014.000000T0000Z-210924T2245Z/
San Diego CA-
341 PM PDT Fri Sep 24 2021

...THE SEVERE THUNDERSTORM WARNING FOR SOUTH CENTRAL SAN DIEGO COUNTY
WILL EXPIRE AT 345 PM PDT...
    
The severe thunderstorm which prompted the warning has moved west to 
southwestern San Diego County. Therefore, the severe thunderstorm 
warning will expire in south central San Diego County.

LAT...LON 3292 11656 3261 11646 3257 11680 3293 11689
TIME...MOT...LOC 2240Z 097DEG 28KT 3281 11729 

$$

Maxwell

The office that day

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

Issued	Product	Office	Counties	Lasted
Sep 24, 8:56 AM PDT	Flash Flood Watch	SGX	Riverside, San Diego	10 hr
Sep 24, 11:08 AM PDT	Beach Hazards Statement	SGX	Orange, San Diego	8 hr
Sep 24, 12:13 PM PDT	Severe Thunderstorm Warning	SGX	San Diego	31 min
Sep 24, 12:21 PM PDT	Flash Flood Warning Considerable damage threat	SGX	San Diego	56 min
Sep 24, 1:24 PM PDT	Severe Thunderstorm Warning	SGX	San Diego	51 min
Sep 24, 1:28 PM PDT	Flash Flood Warning Considerable damage threat	SGX	San Diego	2 hr
Sep 24, 2:09 PM PDT	Flash Flood Warning Considerable damage threat	SGX	San Diego	3 hr
Sep 24, 2:59 PM PDT	Special Weather Statement	SGX	San Diego	61 min
Sep 24, 3:14 PM PDT	Special Marine Warning	SGX		91 min
Sep 24, 3:20 PM PDT	Severe Thunderstorm Warning	SGX	San Diego	55 min
Sep 24, 3:47 PM PDT	Special Weather Statement	SGX	Orange	58 min
Sep 24, 3:56 PM PDT	Special Marine Warning	SGX		94 min
Sep 24, 4:40 PM PDT	Special Marine Warning	SGX		65 min

Nearby

Severe Thunderstorm Warnings in California, 2021 Every 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.