Alert archive / California / Severe Thunderstorm Warnings in 2009

Severe Thunderstorm Warning 19, NWS Eureka, CA

August 5, 2009Humboldt County, Trinity County, California

NWS Eureka, CA issued this severe thunderstorm warning at Aug 5, 2009, 6:11 PM PDT for Humboldt County, Trinity County, California. It was in force for 19 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 5, 2009, 6:11 PM PDT (01:11 UTC)
Expired
Aug 5, 2009, 6:30 PM PDT
In force
19 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), 68 km from the middle of the area, began a volume at 01:14 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, 1.2 hours before the alert went out and 191 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 00:00Z on 2009-08-06Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 277 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 00:00Z on 2009-08-06The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 13 square meters per square second.1939587897Sfc1 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
277 J/kg
Mixed-layer CIN
-42 J/kg
Mixed-layer LCL
3395 m above ground
0-6 km bulk shear
48 kt
0-1 km storm-relative helicity
13 m²/s²
0-3 km storm-relative helicity
148 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.3

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

000 
WUUS56 KEKA 060111
SVREKA
CAC023-105-060130-
/O.NEW.KEKA.SV.W.0019.090806T0111Z-090806T0130Z/

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE
611 PM PDT WED AUG 5 2009

THE NATIONAL WEATHER SERVICE HAS ISSUED A

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

* UNTIL 630 PM PDT

* AT 610 PM PDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  SEVERE THUNDERSTORM CAPABLE OF PRODUCING PENNY SIZE HAIL.  THIS
  STORM WAS LOCATED 7 MILES NORTH OF HYAMPOM...OR 19 MILES SOUTHEAST
  OF WILLOW CREEK...AND MOVING NORTHWEST AT 15 MPH.

* OTHER LOCATIONS IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO BURNT
  RANCH

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 4074 12375 4092 12354 4073 12328 4060 12343
TIME...MOT...LOC 0111Z 131DEG 11KT 4071 12343

$$

MS
1 follow-up statement
000 
WWUS56 KEKA 060120
SVSEKA

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE
620 PM PDT WED AUG 5 2009

CAC023-105-060130-
/O.CON.KEKA.SV.W.0019.000000T0000Z-090806T0130Z/
TRINITY CA-HUMBOLDT CA-
620 PM PDT WED AUG 5 2009

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 630 PM PDT
FOR HUMBOLDT AND TRINITY COUNTIES...

AT 620 PM PDT...NATIONAL WEATHER SERVICE DOPPLER RADAR CONTINUED TO
INDICATE A SEVERE THUNDERSTORM CAPABLE OF PRODUCING PENNY SIZE HAIL. 
THIS STORM WAS LOCATED 6 MILES SOUTH OF BURNT RANCH...OR 17 MILES
SOUTHEAST OF WILLOW CREEK...MOVING NORTHWEST AT 15 MPH.

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

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 4073 12332 4063 12344 4074 12375 4092 12354
TIME...MOT...LOC 0120Z 131DEG 11KT 4073 12346

$$

MS

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 5, 5:00 PM PDTSpecial Weather StatementEKATrinity30 min
Aug 5, 5:10 PM PDTSpecial Weather StatementEKAHumboldt35 min
Aug 5, 5:30 PM PDTSpecial Weather StatementEKATrinity30 min
Aug 5, 5:41 PM PDTSevere Thunderstorm WarningEKATrinity34 min
Aug 5, 6:29 PM PDTSevere Thunderstorm WarningEKAHumboldt, Trinity16 min

Nearby

Severe Thunderstorm Warnings in California, 2009Every severe thunderstorm warning in 2009

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.