Alert archive / California / Severe Thunderstorm Warnings in 2017

Severe Thunderstorm Warning 15, NWS Eureka, CA

September 6, 2017Trinity County, California

NWS Eureka, CA issued this severe thunderstorm warning at Sep 6, 2017, 5:58 PM PDT for Trinity County, California. It was in force for 12 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: Sep 6, 2017, 5:58 PM PDT (00:58 UTC)
Expired: Sep 6, 2017, 6:10 PM PDT
In force: 12 min
Issued by: NWS Eureka, CA
Area: Storm-based polygon
Hail: 1.0 in
Wind: 50.0 mph

County Trinity County, CA

The radar

The Eureka (Bunker Hill) radar (KBHX), 94 km from the middle of the area, began a volume at 00:59 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

Medford/Jackson, OR (KMFR), launched 00:00Z, 1.0 hours before the alert went out and 222 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: 146 J/kg
Mixed-layer CIN: -317 J/kg
Mixed-layer LCL: 1964 m above ground
0-6 km bulk shear: 28 kt
0-1 km storm-relative helicity: -6 m²/s²
0-3 km storm-relative helicity: 62 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.2

Open this sounding in Storm Lab

The text

As transmitted.

324 
WUUS56 KEKA 070058
SVREKA
CAC105-070130-
/O.NEW.KEKA.SV.W.0015.170907T0058Z-170907T0130Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Eureka CA
558 PM PDT WED SEP 6 2017

The National Weather Service in Eureka California has issued a

* Severe Thunderstorm Warning for...
  Central Trinity County in northwestern California...

* Until 630 PM PDT

* At 557 PM PDT, a severe thunderstorm was located near Peanut, or 11
  miles west of Yolla Bolly District Rs, moving northwest at 15 mph.

  HAZARD...Quarter size hail. 

  SOURCE...Radar indicated. 

  IMPACT...Damage to vehicles is expected. 

* Locations impacted include...
  West of Peanut.

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 4035 12312 4033 12319 4045 12331 4051 12320
TIME...MOT...LOC 0057Z 155DEG 11KT 4038 12318 

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

KR

2 follow-up statements

349 
WWUS56 KEKA 070104
SVSEKA

Severe Weather Statement
National Weather Service Eureka CA
604 PM PDT WED SEP 6 2017

CAC105-070130-
/O.CON.KEKA.SV.W.0015.000000T0000Z-170907T0130Z/
Trinity CA-
604 PM PDT WED SEP 6 2017

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 630 PM PDT
FOR CENTRAL TRINITY COUNTY...

At 604 PM PDT, a severe thunderstorm was located near Peanut, or 12
miles south of Hayfork, moving northwest at 15 mph.

HAZARD...Quarter size hail. 

SOURCE...Radar indicated. 

IMPACT...Damage to vehicles is expected. 

Locations impacted include...
Hayfork.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

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 4037 12313 4036 12322 4045 12331 4051 12320
      4038 12313
TIME...MOT...LOC 0104Z 155DEG 11KT 4040 12319 

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

KR

201 
WWUS56 KEKA 070110
SVSEKA

Severe Weather Statement
National Weather Service Eureka CA
610 PM PDT WED SEP 6 2017

CAC105-070119-
/O.CAN.KEKA.SV.W.0015.000000T0000Z-170907T0130Z/
Trinity CA-
610 PM PDT WED SEP 6 2017

...THE SEVERE THUNDERSTORM WARNING FOR CENTRAL TRINITY COUNTY IS
CANCELLED...
                
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 has been cancelled.  However small hail is
still possible with this thunderstorm.

LAT...LON 4037 12313 4036 12322 4045 12331 4051 12320
      4038 12313
TIME...MOT...LOC 0108Z 155DEG 11KT 4042 12320 

$$

KR

The office that day

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

Issued	Product	Office	Counties	Lasted
Sep 6, 5:40 PM PDT	Severe Thunderstorm Warning	EKA	Trinity	20 min
Sep 6, 6:13 PM PDT	Special Weather Statement	EKA	Trinity	17 min
Sep 7, 3:15 AM PDT	Small Craft Advisory	EKA		10 days
Sep 7, 4:24 AM PDT	Special Weather Statement	EKA		51 min
Sep 7, 4:27 AM PDT	Special Weather Statement	EKA	Trinity	33 min
Sep 7, 5:34 AM PDT	Special Weather Statement	EKA	Del Norte	26 min
Sep 7, 5:59 AM PDT	Special Weather Statement	EKA	Del Norte	46 min
Sep 7, 6:49 AM PDT	Special Weather Statement	EKA	Del Norte	26 min
Sep 7, 7:22 AM PDT	Special Weather Statement	EKA	Del Norte	23 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.