Alert archive / California / Severe Thunderstorm Warnings in 2017

Severe Thunderstorm Warning 7, NWS Eureka, CA

August 9, 2017Mendocino County, California

NWS Eureka, CA issued this severe thunderstorm warning at Aug 9, 2017, 3:10 PM PDT for Mendocino County, California. It was in force for 35 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 9, 2017, 3:10 PM PDT (22:10 UTC)
Expired: Aug 9, 2017, 3:45 PM PDT
In force: 35 min
Issued by: NWS Eureka, CA
Area: Storm-based polygon
Hail: 1.0 in
Wind: 50.0 mph

County Mendocino County, CA

The radar

The Beale AFB radar (KBBX), 113 km from the middle of the area, began a volume at 22:13 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

Oakland, CA (KOAK), launched 12:00Z, 10.2 hours before the alert went out and 219 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: 797 m above ground
0-6 km bulk shear: 5 kt
0-1 km storm-relative helicity: 3 m²/s²
0-3 km storm-relative helicity: 17 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

497 
WUUS56 KEKA 092210
SVREKA
CAC045-092245-
/O.NEW.KEKA.SV.W.0007.170809T2210Z-170809T2245Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Eureka CA
310 PM PDT WED AUG 9 2017

The National Weather Service in Eureka California has issued a

* Severe Thunderstorm Warning for...
  East central Mendocino County in northwestern California...

* Until 345 PM PDT

* At 310 PM PDT, a severe thunderstorm was located 13 miles west of
  Alder Springs, moving southwest at 10 mph.

  HAZARD...Quarter size hail. 

  SOURCE...Radar indicated. 

* This severe thunderstorm will remain over mainly rural areas of
  east central Mendocino County.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Large hail and damaging winds and continuous cloud to ground
lightning is occurring with this storm. Move indoors immediately.
Lightning is one of nature's leading killers. Remember, if you can
hear thunder, you are close enough to be struck by lightning.

&&

LAT...LON 3953 12289 3953 12293 3952 12294 3952 12298
      3959 12308 3976 12297 3972 12291 3971 12291
      3970 12289
TIME...MOT...LOC 2210Z 048DEG 8KT 3958 12296 

HAIL...1.00IN
WIND...<50MPH
 
$$

RCL

1 follow-up statement

959 
WWUS56 KEKA 092238
SVSEKA

Severe Weather Statement
National Weather Service Eureka CA
338 PM PDT WED AUG 9 2017

CAC045-092248-
/O.EXP.KEKA.SV.W.0007.000000T0000Z-170809T2245Z/
Mendocino CA-
338 PM PDT WED AUG 9 2017

...THE SEVERE THUNDERSTORM WARNING FOR EAST CENTRAL MENDOCINO COUNTY
WILL EXPIRE AT 345 PM PDT...
                
The storm which prompted the warning has weakened below severe
limits, and no longer poses an immediate threat to life or property.
Therefore the warning will be allowed to expire.  However small hail
and gusty winds are still possible with this thunderstorm.

To report severe weather, contact your nearest law enforcement
agency. They will relay your report to the National Weather Service
Eureka California.

LAT...LON 3953 12289 3953 12293 3952 12294 3952 12298
      3959 12308 3976 12297 3972 12291 3971 12291
      3970 12289
TIME...MOT...LOC 2238Z 048DEG 8KT 3954 12302 

$$

GARNER

The office that day

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

Issued	Product	Office	Counties	Lasted
Aug 8, 5:26 PM PDT	Special Weather Statement	EKA	Trinity	34 min
Aug 8, 5:52 PM PDT	Special Weather Statement	EKA	Trinity	23 min
Aug 8, 6:51 PM PDT	Special Weather Statement	EKA		24 min
Aug 8, 7:14 PM PDT	Special Weather Statement	EKA		31 min
Aug 9, 1:32 PM PDT	Special Weather Statement	EKA		43 min
Aug 9, 1:50 PM PDT	Severe Thunderstorm Warning	EKA	Mendocino, Trinity	23 min
Aug 9, 2:28 PM PDT	Severe Thunderstorm Warning	EKA	Trinity	32 min
Aug 9, 2:34 PM PDT	Special Weather Statement	EKA	Mendocino	26 min
Aug 9, 2:40 PM PDT	Special Weather Statement	EKA	Trinity	35 min
Aug 9, 2:50 PM PDT	Severe Thunderstorm Warning	EKA	Mendocino	25 min
Aug 9, 2:52 PM PDT	Special Weather Statement	EKA	Trinity	23 min
Aug 9, 3:05 PM PDT	Severe Thunderstorm Warning	EKA	Trinity	25 min
Aug 9, 3:23 PM PDT	Special Weather Statement	EKA	Trinity	22 min
Aug 9, 3:43 PM PDT	Special Weather Statement	EKA	Mendocino	32 min
Aug 9, 3:47 PM PDT	Special Weather Statement	EKA	Trinity	28 min
Aug 9, 3:50 PM PDT	Special Weather Statement	EKA	Trinity	25 min
Aug 9, 4:09 PM PDT	Special Weather Statement	EKA	Mendocino	36 min
Aug 9, 4:12 PM PDT	Special Weather Statement	EKA	Trinity	33 min
Aug 9, 4:41 PM PDT	Special Weather Statement	EKA	Trinity	34 min

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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.