Alert archive / California / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 13, NWS San Diego, CA

September 24, 2021San Diego County, California

NWS San Diego, CA issued this severe thunderstorm warning at Sep 24, 2021, 1:24 PM PDT for San Diego County, California. It was in force for 51 min. 5 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, 1:24 PM PDT (20:24 UTC)
Expired: Sep 24, 2021, 2:15 PM PDT
In force: 51 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), 46 km from the middle of the area, began a volume at 20:25 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, 1:24 PM PDT	HAIL 1	8 Nw Warner Springs, CA	CORRECTS PREVIOUS HAIL REPORT FROM 8 NW WARNER SPRINGS. SPOTTER USED RULER AND QUARTER.
Sep 24, 1:24 PM PDT	HAIL 1	8 Nw Warner Springs, CA
Sep 24, 1:30 PM PDT	TSTM WND GST 51	3 Wsw Palomar Mountain, CA	MESONET STATION CCRSD CUCA RANCH (SDGE), ORGANIZED STRONG THUNDERSTORMS.
Sep 24, 1:37 PM PDT	HAIL 0.5	Palomar Mountain, CA	ACCUMULATING HAIL ABOUT 4 INCHES DEEP AT 33120 CANFIELD ROAD.
Sep 24, 2:15 PM PDT	HAIL 0.5	8 Nw Warner Springs, CA	THUNDERSTORM ALSO PRODUCED 0.89 INCH OF RAIN IN 45 MINUTES.

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, 8.4 hours before the alert went out and 65 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.

320 
WUUS56 KSGX 242024
SVRSGX
CAC073-242115-
/O.NEW.KSGX.SV.W.0013.210924T2024Z-210924T2115Z/

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

The National Weather Service in San Diego has issued a

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

* Until 215 PM PDT.

* At 123 PM PDT, a severe thunderstorm was located 7 miles west of
  Palomar Mountain State Park, or 8 miles north of Valley Center,
  moving southwest at 10 mph.

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

  SOURCE...Radar indicated. A spotter reported up to one-inch
           diameter hail at Birch Hill on Palomar Mountain.

  IMPACT...Hail damage to vehicles is expected. Expect wind damage 
           to roofs, siding, and trees.

* Locations impacted include...
  Valley Center, Julian, Fallbrook, Escondido, Warner Springs,
  Palomar Mountain, Hwy 79 Between Oak Grove And Aguanga, Hwy 79
  Between Warner Springs And Oak Grove, Hwy 79 Between Santa Ysabel
  And Warner Springs and Lake Henshaw.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3341 11663 3305 11661 3314 11707 3341 11710
TIME...MOT...LOC 2023Z 098DEG 49KT 3335 11704 

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

$$

Maxwell

1 follow-up statement

439 
WWUS56 KSGX 242113
SVSSGX

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

CAC073-242122-
/O.EXP.KSGX.SV.W.0013.000000T0000Z-210924T2115Z/
San Diego CA-
213 PM PDT Fri Sep 24 2021

...THE SEVERE THUNDERSTORM WARNING FOR NORTH CENTRAL SAN DIEGO COUNTY
WILL EXPIRE AT 215 PM PDT...
    
The severe thunderstorm which prompted the warning has weakened to 
below severe levels. Therefore, the warning will be allowed to 
expire.

LAT...LON 3341 11663 3305 11661 3314 11707 3341 11710
TIME...MOT...LOC 2112Z 098DEG 49KT 3343 11773 

$$

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, 1:28 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, 2:41 PM PDT	Severe Thunderstorm Warning	SGX	San Diego	64 min
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.