Alert archive / California / Severe Thunderstorm Warnings in 2013

Severe Thunderstorm Warning 9, NWS Eureka, CA

August 21, 2013Humboldt County, Trinity County, California

NWS Eureka, CA issued this severe thunderstorm warning at Aug 21, 2013, 2:22 PM PDT for Humboldt County, Trinity County, California. It was in force for 38 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 21, 2013, 2:22 PM PDT (21:22 UTC)
Expired
Aug 21, 2013, 3:00 PM PDT
In force
38 min
Issued by
NWS Eureka, CA
Area
Storm-based polygon

Counties Humboldt County, CA, Trinity County, CA

The radar

The Eureka (Bunker Hill) radar (KBHX), 55 km from the middle of the area, began a volume at 21:25 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, 9.4 hours before the alert went out and 202 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 2013-08-21Temperature 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, Medford/Jackson, OR at 12:00Z on 2013-08-21The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 6 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
2413 m above ground
0-6 km bulk shear
6 kt
0-1 km storm-relative helicity
6 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, in the capitals the NWS used until 2016.

268 
WUUS56 KEKA 212122
SVREKA
CAC023-105-212200-
/O.NEW.KEKA.SV.W.0009.130821T2122Z-130821T2200Z/

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE EUREKA CA
222 PM PDT WED AUG 21 2013

THE NATIONAL WEATHER SERVICE HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  HUMBOLDT COUNTY IN NORTHWEST CALIFORNIA...
  TRINITY COUNTY IN NORTHWEST CALIFORNIA...

* UNTIL 300 PM PDT

* AT 214 PM PDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  SEVERE THUNDERSTORM CAPABLE OF PRODUCING QUARTER SIZE HAIL.  THIS
  STORM WAS LOCATED OVER HUMBOLDT COUNTY...OR 26 MILES SOUTH OF
  WILLOW CREEK...AND MOVING NORTHWEST AT 20 MPH.

* THE SEVERE THUNDERSTORM WILL OTHERWISE REMAIN OVER MAINLY RURAL
  AREAS OF THE INDICATED COUNTY.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

THIS IS A DANGEROUS STORM. IF YOU ARE IN ITS PATH...PREPARE
IMMEDIATELY FOR DAMAGING WINDS...DESTRUCTIVE HAIL...AND DEADLY CLOUD
TO GROUND LIGHTNING. PEOPLE OUTSIDE SHOULD MOVE TO A SHELTER...
PREFERABLY INSIDE A STRONG BUILDING BUT AWAY FROM WINDOWS.

&&

LAT...LON 4075 12388 4086 12362 4056 12342 4047 12362
TIME...MOT...LOC 2122Z 149DEG 19KT 4060 12359

$$

MS
2 follow-up statements
677 
WWUS56 KEKA 212137
SVSEKA

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE EUREKA CA
237 PM PDT WED AUG 21 2013

CAC023-105-212200-
/O.CON.KEKA.SV.W.0009.000000T0000Z-130821T2200Z/
HUMBOLDT CA-TRINITY CA-
237 PM PDT WED AUG 21 2013

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 300 PM PDT
FOR TRINITY AND HUMBOLDT COUNTIES...

AT 225 PM PDT...NATIONAL WEATHER SERVICE DOPPLER RADAR CONTINUED TO
INDICATE A SEVERE THUNDERSTORM CAPABLE OF PRODUCING QUARTER SIZE
HAIL.  THIS STORM WAS LOCATED OVER HUMBOLDT COUNTY...OR 23 MILES
SOUTH OF WILLOW CREEK...MOVING NORTHWEST AT 20 MPH.

THE SEVERE THUNDERSTORM WILL OTHERWISE REMAIN OVER MAINLY RURAL AREAS
OF THE INDICATED COUNTY.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

THIS IS A DANGEROUS STORM. IF YOU ARE IN ITS PATH...PREPARE
IMMEDIATELY FOR DAMAGING WINDS...DESTRUCTIVE HAIL...AND DEADLY CLOUD
TO GROUND LIGHTNING. PEOPLE OUTSIDE SHOULD MOVE TO A SHELTER...
PREFERABLY INSIDE A STRONG BUILDING BUT AWAY FROM WINDOWS.

&&

LAT...LON 4054 12346 4049 12360 4075 12388 4086 12362
TIME...MOT...LOC 2137Z 149DEG 19KT 4067 12364

$$

MS
391 
WWUS56 KEKA 212201
SVSEKA

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE EUREKA CA
301 PM PDT WED AUG 21 2013

CAC023-105-212211-
/O.EXP.KEKA.SV.W.0009.000000T0000Z-130821T2200Z/
HUMBOLDT CA-TRINITY CA-
301 PM PDT WED AUG 21 2013

...THE SEVERE THUNDERSTORM WARNING FOR TRINITY AND HUMBOLDT COUNTIES
HAS EXPIRED...

LAT...LON 4054 12346 4049 12360 4075 12388 4086 12362
TIME...MOT...LOC 2137Z 149DEG 19KT 4067 12364

$$

MS

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 21, 3:09 AM PDTSmall Craft AdvisoryEKA12 hr
Aug 21, 1:18 PM PDTSpecial Weather StatementEKATrinity42 min
Aug 21, 1:59 PM PDTSpecial Weather StatementEKAHumboldt46 min
Aug 21, 2:40 PM PDTSpecial Weather StatementEKATrinity50 min
Aug 21, 2:56 PM PDTSevere Thunderstorm WarningEKATrinity49 min
Aug 21, 4:18 PM PDTSpecial Weather StatementEKADel Norte42 min
Aug 21, 4:33 PM PDTSpecial Weather StatementEKATrinity27 min

Nearby

Severe Thunderstorm Warnings in California, 2013Every severe thunderstorm warning in 2013

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.