Alert archive / California / Severe Thunderstorm Warnings in 2017

Severe Thunderstorm Warning 3, NWS Eureka, CA

August 9, 2017Mendocino County, Trinity County, California

NWS Eureka, CA issued this severe thunderstorm warning at Aug 9, 2017, 1:50 PM PDT for Mendocino County, Trinity County, California. It was in force for 23 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, 1:50 PM PDT (20:50 UTC)
Expired
Aug 9, 2017, 2:13 PM PDT
In force
23 min
Issued by
NWS Eureka, CA
Area
Storm-based polygon
Hail
1.0 in
Wind
60.0 mph

Counties Mendocino County, CA, Trinity County, CA

The radar

The Eureka (Bunker Hill) radar (KBHX), 122 km from the middle of the area, began a volume at 20:50 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, 8.8 hours before the alert went out and 263 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, Oakland, CA at 12:00Z on 2017-08-09Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 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, Oakland, CA at 12:00Z on 2017-08-09The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 3 square meters per square second.193958Sfc1 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
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.

856 
WUUS56 KEKA 092050
SVREKA
CAC045-105-092130-
/O.NEW.KEKA.SV.W.0003.170809T2050Z-170809T2130Z/

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

The National Weather Service in Eureka California has issued a

* Severe Thunderstorm Warning for...
  Northern Mendocino County in northwestern California...
  South central Trinity County in northwestern California...

* Until 230 PM PDT

* At 150 PM, a severe thunderstorm was located 15 miles southwest of 
  Saddle Camp, or 20 miles northeast of Covelo, moving southwest at 
  5 mph.

  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. 

* This severe thunderstorm will remain over mainly rural areas of
  northern Mendocino and south central Trinity Counties.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Prepare immediately for large hail and damaging winds. People outside
should move immediately to shelter inside a strong building. Stay
away from windows.

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

Torrential rainfall is occurring with this storm, and may lead to
flash flooding. Do not drive your vehicle through flooded roadways.

&&

LAT...LON 3984 12303 4000 12332 4015 12310 4009 12297
      4008 12297 4005 12295 4003 12295 4002 12296
      4001 12295 4000 12295 3999 12294
TIME...MOT...LOC 2050Z 034DEG 6KT 4006 12306 

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

SEC
1 follow-up statement
992 
WWUS56 KEKA 092113
SVSEKA

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

CAC045-105-092122-
/O.CAN.KEKA.SV.W.0003.000000T0000Z-170809T2130Z/
Mendocino CA-Trinity CA-
213 PM PDT WED AUG 9 2017

...THE SEVERE THUNDERSTORM WARNING FOR NORTHERN MENDOCINO AND SOUTH
CENTRAL TRINITY COUNTIES 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.

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

LAT...LON 3984 12303 4000 12332 4015 12310 4009 12297
      4008 12297 4005 12295 4003 12295 4002 12296
      4001 12295 4000 12295 3999 12294
TIME...MOT...LOC 2111Z 034DEG 6KT 4003 12309 

$$

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, 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, 3:05 PM PDTSevere Thunderstorm WarningEKATrinity25 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.