Alert archive / California / Severe Thunderstorm Warnings in 2017

Severe Thunderstorm Warning 11, NWS Eureka, CA

August 10, 2017Trinity County, California

NWS Eureka, CA issued this severe thunderstorm warning at Aug 10, 2017, 4:08 PM PDT for Trinity County, California. It was in force for 37 min. 1 report 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
Aug 10, 2017, 4:08 PM PDT (23:08 UTC)
Expired
Aug 10, 2017, 4:45 PM PDT
In force
37 min
Issued by
NWS Eureka, CA
Area
Storm-based polygon
Hail
1.0 in
Wind
60.0 mph

County Trinity County, CA

The radar

The Eureka (Bunker Hill) radar (KBHX), 80 km from the middle of the area, began a volume at 23:10 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

TimeReportWhereRemark
Aug 10, 4:20 PM PDTHAIL 12 W Burnt Ranch, CAESTIMATED THE LARGEST HAIL STONES TO BE THE SIZE OF A QUARTER. STORM LASTED FROM SOMEWHERE BETWEEN 4 AND 430 UNTIL 5 PM. RAIN WAS VERY HEAVY.

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The nearest sounding before it

Medford/Jackson, OR (KMFR), launched 12:00Z, 11.1 hours before the alert went out and 178 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-pSkew-T log-p diagram, Medford/Jackson, OR at 12:00Z on 2017-08-10Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 130 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Medford/Jackson, OR at 12:00Z on 2017-08-10The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -5 square meters per square second.1939Sfc1 km3 km6 km9 kmRMLM
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
130 J/kg
Mixed-layer CIN
-439 J/kg
Mixed-layer LCL
1837 m above ground
0-6 km bulk shear
13 kt
0-1 km storm-relative helicity
-5 m²/s²
0-3 km storm-relative helicity
32 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

570 
WUUS56 KEKA 102308
SVREKA
CAC105-102345-
/O.NEW.KEKA.SV.W.0011.170810T2308Z-170810T2345Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Eureka CA
408 PM PDT THU AUG 10 2017

The National Weather Service in Eureka California has issued a

* Severe Thunderstorm Warning for...
  West central Trinity County in northwestern California...

* Until 445 PM PDT

* At 408 PM PDT, a severe thunderstorm was located over Burnt Ranch,
  or 11 miles southeast of Willow Creek, and is nearly stationary.

  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...
  Burnt Ranch.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4093 12352 4092 12350 4084 12335 4072 12341
      4079 12355
TIME...MOT...LOC 2308Z 030DEG 2KT 4082 12347 

HAIL...1.00IN
WIND...60MPH
 
$$

RPA
2 follow-up statements
742 
WWUS56 KEKA 102323
SVSEKA

Severe Weather Statement
National Weather Service Eureka CA
423 PM PDT THU AUG 10 2017

CAC105-102345-
/O.CON.KEKA.SV.W.0011.000000T0000Z-170810T2345Z/
Trinity CA-
423 PM PDT THU AUG 10 2017

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 445 PM PDT
FOR NORTHWESTERN TRINITY COUNTY...

At 423 PM PDT, a severe thunderstorm was located over Burnt Ranch, or
11 miles southeast of Willow Creek, and is nearly stationary.

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...
Burnt Ranch.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4090 12351 4089 12349 4084 12337 4074 12342
      4079 12355
TIME...MOT...LOC 2323Z 030DEG 2KT 4081 12348 

HAIL...1.00IN
WIND...60MPH
 
$$

RPA
480 
WWUS56 KEKA 102346
SVSEKA

Severe Weather Statement
National Weather Service Eureka CA
446 PM PDT THU AUG 10 2017

CAC105-102355-
/O.EXP.KEKA.SV.W.0011.000000T0000Z-170810T2345Z/
Trinity CA-
446 PM PDT THU AUG 10 2017

...THE SEVERE THUNDERSTORM WARNING FOR NORTHWESTERN TRINITY COUNTY
HAS EXPIRED...
    
The severe thunderstorm which prompted the warning has 
weakened. Therefore, the warning has been allowed to expire.

LAT...LON 4090 12351 4089 12349 4084 12337 4074 12342
      4079 12355
TIME...MOT...LOC 2345Z 030DEG 2KT 4080 12349 

$$

RPA

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 10, 1:17 PM PDTSpecial Weather StatementEKATrinity28 min
Aug 10, 1:57 PM PDTSpecial Weather StatementEKATrinity33 min
Aug 10, 2:09 PM PDTSpecial Weather StatementEKATrinity36 min
Aug 10, 2:26 PM PDTSmall Craft AdvisoryEKA8 days
Aug 10, 2:28 PM PDTSpecial Weather StatementEKATrinity32 min
Aug 10, 2:43 PM PDTSpecial Weather StatementEKATrinity32 min
Aug 10, 3:06 PM PDTSpecial Weather StatementEKATrinity39 min
Aug 10, 3:28 PM PDTSevere Thunderstorm WarningEKATrinity32 min
Aug 10, 3:30 PM PDTSevere Thunderstorm WarningEKATrinity30 min
Aug 10, 3:53 PM PDTSpecial Weather StatementEKATrinity37 min
Aug 10, 4:03 PM PDTSpecial Weather StatementEKAMendocino42 min
Aug 10, 4:05 PM PDTSevere Thunderstorm WarningEKATrinity25 min
Aug 10, 4:30 PM PDTSevere Thunderstorm WarningEKATrinity30 min
Aug 10, 4:45 PM PDTAreal Flood AdvisoryEKATrinity105 min
Aug 10, 4:48 PM PDTSpecial Weather StatementEKAHumboldt27 min
Aug 10, 4:52 PM PDTSpecial Weather StatementEKATrinity23 min

Nearby

Severe Thunderstorm Warnings in California, 2017Every 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.