Alert archive / California / Severe Thunderstorm Warnings in 2017

Severe Thunderstorm Warning 2, NWS San Diego, CA

January 20, 2017Orange County, California

NWS San Diego, CA issued this severe thunderstorm warning at Jan 20, 2017, 12:52 PM PST for Orange County, California. It was in force for 23 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: Jan 20, 2017, 12:52 PM PST (20:52 UTC)
Expired: Jan 20, 2017, 1:15 PM PST
In force: 23 min
Issued by: NWS San Diego, CA
Area: Storm-based polygon

County Orange County, CA

The radar

The Santa Ana Mts radar (KSOX), 32 km from the middle of the area, began a volume at 20:55 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
Jan 20, 1:15 PM PST	TSTM WND DMG	1 Ese Costa Mesa, CA	EQUIPMENT DAMAGE CAUSED BY WIND, 63 CUSTOMERS WITHOUT POWER.
Jan 20, 1:15 PM PST	TSTM WND DMG	2 Wsw Costa Mesa, CA	POWER POLES AND LINES DOWN. 63 CUSTOMERS WITHOUT POWER.
Jan 20, 1:24 PM PST	TSTM WND DMG	2 W Costa Mesa, CA	PALM TREE BLOWN DOWN ON BROOKHURST ST. .

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, 8.9 hours before the alert went out and 118 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: 41 J/kg
Mixed-layer CIN: -2 J/kg
Mixed-layer LCL: 618 m above ground
0-6 km bulk shear: 50 kt
0-1 km storm-relative helicity: 91 m²/s²
0-3 km storm-relative helicity: 133 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

430 
WUUS56 KSGX 202052
SVRSGX
CAC059-202115-
/O.NEW.KSGX.SV.W.0002.170120T2052Z-170120T2115Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service San Diego CA
1252 PM PST FRI JAN 20 2017

The National Weather Service in San Diego has issued a

* Severe Thunderstorm Warning for...
  Northwestern Orange County in southwestern California...

* Until 115 PM PST

* At 1251 PM PST, Doppler radar indicated a severe thunderstorm
  capable of producing damaging winds in excess of 60 mph. This storm
  was located 12 miles southwest of Huntington Beach, and moving east
  at 40 mph.

* Locations impacted include...
  Anaheim, Santa Ana, Irvine, Huntington Beach, Garden Grove, Costa
  Mesa, Mission Viejo, Tustin, Seal Beach, Laguna Beach, Newport
  Beach, Westminster, Buena Park, Fountain Valley, Aliso Viejo,
  Cypress, Stanton, Laguna Woods, Los Alamitos and Newport Coast.

The Severe Thunderstorm Warning includes John Wayne Airport.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Severe thunderstorms can produce damaging winds and heavy rain. For
your protection, move to an interior room on the lowest floor of
your home or business. Heavy rains flood roads quickly so do not
drive into areas where water covers the road.

Doppler radar has indicated some weak rotation within this storm.
Although a tornado is not immediately likely, if one is spotted, act
quickly and move to a place of safety in a sturdy structure, such as
a basement or small interior room.

&&

LAT...LON 3386 11799 3364 11761 3355 11780 3361 11788
      3362 11791 3361 11791 3360 11790 3360 11791
      3361 11792 3362 11792 3368 11804 3373 11809
      3374 11812
TIME...MOT...LOC 2051Z 249DEG 39KT 3355 11813 

$$

12

1 follow-up statement

887 
WWUS56 KSGX 202112
SVSSGX

Severe Weather Statement
National Weather Service San Diego CA
112 PM PST FRI JAN 20 2017

CAC059-202122-
/O.EXP.KSGX.SV.W.0002.000000T0000Z-170120T2115Z/
Orange CA-
112 PM PST FRI JAN 20 2017

...THE SEVERE THUNDERSTORM WARNING FOR NORTHWESTERN ORANGE COUNTY
WILL EXPIRE AT 115 PM PST...
        
The storm which prompted the warning has weakened below severe limits
and exited the warned area. Therefore the warning will be allowed to
expire. However gusty winds are still possible with this
thunderstorm.

LAT...LON 3386 11799 3364 11761 3355 11780 3361 11788
      3362 11791 3361 11791 3360 11790 3360 11791
      3361 11792 3362 11792 3368 11804 3373 11809
      3374 11812
TIME...MOT...LOC 2112Z 249DEG 39KT 3361 11795 

$$

12

The office that day

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

Issued	Product	Office	Counties	Lasted
Jan 20, 7:56 AM PST	Beach Hazards Statement	SGX	Orange, San Diego	12 hr
Jan 20, 10:41 AM PST	Areal Flood Advisory	SGX	Orange, Riverside, San Diego	9 hr
Jan 20, 11:46 AM PST	Areal Flood Advisory	SGX	San Bernardino	8 hr
Jan 20, 12:38 PM PST	Severe Thunderstorm Warning	SGX	Orange	22 min
Jan 20, 12:46 PM PST	Areal Flood Advisory	SGX	San Diego	8 hr
Jan 20, 1:20 PM PST	Areal Flood Advisory	SGX	Orange, Riverside, San Bernardino	6 hr
Jan 20, 1:33 PM PST	Flash Flood Warning	SGX	San Bernardino	5 hr
Jan 20, 1:51 PM PST	Severe Thunderstorm Warning	SGX	San Diego	54 min
Jan 20, 2:03 PM PST	Areal Flood Advisory	SGX	Riverside, San Bernardino	5 hr
Jan 20, 2:25 PM PST	Severe Thunderstorm Warning	SGX	San Diego	50 min
Jan 20, 2:38 PM PST	Flash Flood Warning	SGX	San Diego	3 hr
Jan 20, 2:59 PM PST	Flash Flood Warning	SGX	San Diego	6 hr

Nearby

Severe Thunderstorm Warnings in California, 2017 Every severe thunderstorm warning in 2017

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.