Alert archive / California / Severe Thunderstorm Warnings in 2017

Severe Thunderstorm Warning 6, NWS Eureka, CA

August 9, 2017Trinity County, California

NWS Eureka, CA issued this severe thunderstorm warning at Aug 9, 2017, 3:05 PM PDT for Trinity County, California. It was in force for 25 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, 3:05 PM PDT (22:05 UTC)
Expired
Aug 9, 2017, 3:30 PM PDT
In force
25 min
Issued by
NWS Eureka, CA
Area
Storm-based polygon
Hail
1.25 in
Wind
50.0 mph

County Trinity County, CA

The radar

The Eureka (Bunker Hill) radar (KBHX), 95 km from the middle of the area, began a volume at 22:07 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 12:00Z, 10.1 hours before the alert went out and 168 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 2017-08-09Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 166 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 2017-08-09The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -4 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
166 J/kg
Mixed-layer CIN
-462 J/kg
Mixed-layer LCL
1690 m above ground
0-6 km bulk shear
11 kt
0-1 km storm-relative helicity
-4 m²/s²
0-3 km storm-relative helicity
117 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

688 
WUUS56 KEKA 092205
SVREKA
CAC105-092230-
/O.NEW.KEKA.SV.W.0006.170809T2205Z-170809T2230Z/

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

The National Weather Service in Eureka California has issued a

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

* Until 330 PM PDT

* At 304 PM PDT, a severe thunderstorm was located near Denny, or 17
  miles east of Willow Creek, moving southwest at 15 mph.

  HAZARD...Half dollar size hail. 

  SOURCE...Radar indicated. 

  IMPACT...Damage to vehicles is expected. 

* Locations impacted include...
  Denny.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4101 12328 4090 12316 4081 12327 4081 12339
      4093 12347
TIME...MOT...LOC 2204Z 061DEG 12KT 4089 12331 

HAIL...1.25IN
WIND...<50MPH
 
$$

GARNER
2 follow-up statements
308 
WWUS56 KEKA 092218
SVSEKA

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

CAC105-092230-
/O.CON.KEKA.SV.W.0006.000000T0000Z-170809T2230Z/
Trinity CA-
318 PM PDT WED AUG 9 2017

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 330 PM PDT
FOR WEST CENTRAL TRINITY COUNTY...

At 317 PM PDT, a severe thunderstorm was located near Denny, or 14
miles east of Willow Creek, moving southwest at 15 mph.

HAZARD...Half dollar size hail. 

SOURCE...Radar indicated. 

IMPACT...Damage to vehicles is expected. 

Locations impacted include...
Denny.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4098 12335 4096 12323 4090 12316 4081 12327
      4081 12339 4093 12347
TIME...MOT...LOC 2217Z 061DEG 12KT 4087 12336 

HAIL...1.25IN
WIND...<50MPH
 
$$

GARNER
966 
WWUS56 KEKA 092224
SVSEKA

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

CAC105-092233-
/O.EXP.KEKA.SV.W.0006.000000T0000Z-170809T2230Z/
Trinity CA-
324 PM PDT WED AUG 9 2017

...THE SEVERE THUNDERSTORM WARNING FOR WEST CENTRAL TRINITY COUNTY
WILL EXPIRE AT 330 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 4098 12335 4096 12323 4090 12316 4081 12327
      4081 12339 4093 12347
TIME...MOT...LOC 2223Z 061DEG 12KT 4086 12338 

$$

GARNER

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 8, 5:26 PM PDTSpecial Weather StatementEKATrinity34 min
Aug 8, 5:52 PM PDTSpecial Weather StatementEKATrinity23 min
Aug 8, 6:51 PM PDTSpecial Weather StatementEKA24 min
Aug 8, 7:14 PM PDTSpecial Weather StatementEKA31 min
Aug 9, 1:32 PM PDTSpecial Weather StatementEKA43 min
Aug 9, 1:50 PM PDTSevere Thunderstorm WarningEKAMendocino, Trinity23 min
Aug 9, 2:28 PM PDTSevere Thunderstorm WarningEKATrinity32 min
Aug 9, 2:34 PM PDTSpecial Weather StatementEKAMendocino26 min
Aug 9, 2:40 PM PDTSpecial Weather StatementEKATrinity35 min
Aug 9, 2:50 PM PDTSevere Thunderstorm WarningEKAMendocino25 min
Aug 9, 2:52 PM PDTSpecial Weather StatementEKATrinity23 min
Aug 9, 3:10 PM PDTSevere Thunderstorm WarningEKAMendocino35 min
Aug 9, 3:23 PM PDTSpecial Weather StatementEKATrinity22 min
Aug 9, 3:43 PM PDTSpecial Weather StatementEKAMendocino32 min
Aug 9, 3:47 PM PDTSpecial Weather StatementEKATrinity28 min
Aug 9, 3:50 PM PDTSpecial Weather StatementEKATrinity25 min
Aug 9, 4:09 PM PDTSpecial Weather StatementEKAMendocino36 min
Aug 9, 4:12 PM PDTSpecial Weather StatementEKATrinity33 min
Aug 9, 4:41 PM PDTSpecial Weather StatementEKATrinity34 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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.