Alert archive / California / Severe Thunderstorm Warnings in 2015

Severe Thunderstorm Warning 5, NWS Eureka, CA

December 10, 2015Humboldt County, California

NWS Eureka, CA issued this severe thunderstorm warning at Dec 10, 2015, 12:09 PM PST for Humboldt County, California. It was in force for 21 min. 6 reports 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
Dec 10, 2015, 12:09 PM PST (20:09 UTC)
Expired
Dec 10, 2015, 12:30 PM PST
In force
21 min
Issued by
NWS Eureka, CA
Area
Storm-based polygon

County Humboldt County, CA

The radar

The Eureka (Bunker Hill) radar (KBHX), 51 km from the middle of the area, began a volume at 20:12 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
Dec 10, 12:18 PM PSTHAIL 0.251 S Fieldbrook, CAFROM SOCIAL MEDIA... USER SENT A PHOTO OF ESTIMATED PEA SIZE HAIL IN FIELDBROOK, CA.
Dec 10, 12:23 PM PSTHAIL 0.253 N Arcata, CAFROM SOCIAL MEDIA... A USER SENT A PHOTO OF SMALL HAIL COVERING THE CENTRAL AVENUE EXIT FROM HWY 101 TO MCKINELYVILLE.
Dec 10, 12:23 PM PSTHAIL 0.55 Nnw Arcata, CAFROM SOCIAL MEDIA... ESTIMATED DIME SIZED HAIL FROM MCKINLEYVILLE.
Dec 10, 12:23 PM PSTHAIL 0.885 Nnw Arcata, CAFROM SOCIAL MEDIA...ESTIMATED NICKLE SIZED HAIL... USER POSTED PHOTO OF HAIL.
Dec 10, 12:25 PM PSTHAIL 15 N Arcata, CAPEA AND QUARTER SIZED HAIL STONES REPORTED FROM SOCIAL MEDIA... PHOTO INCLUDED COINS TO MEASURE THE STONES.
Dec 10, 12:35 PM PSTHAIL 0.753 N Arcata, CAFROM SOCIAL MEDIA... A PHOTO REPORT CAME IN AT 1235 PM PST FROM NORTH BANK RD IN MCKINLEYVILLE. 1/2 TO 3/4 INCH HAIL STONES WERE MEASURED...PHOTO INCLUDED MEASURING TAPE.

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, 8.2 hours before the alert went out and 192 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 2015-12-10Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 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 2015-12-10The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 198 square meters per square second.1939587897117136156Sfc1 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
868 m above ground
0-6 km bulk shear
89 kt
0-1 km storm-relative helicity
198 m²/s²
0-3 km storm-relative helicity
75 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.

918 
WUUS56 KEKA 102009
SVREKA
CAC023-102030-
/O.NEW.KEKA.SV.W.0005.151210T2009Z-151210T2030Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE EUREKA
1209 PM PST THU DEC 10 2015

THE NATIONAL WEATHER SERVICE IN EUREKA CALIFORNIA HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  CENTRAL HUMBOLDT COUNTY IN NORTHWESTERN CALIFORNIA...

* UNTIL 1230 PM PST

* AT 1208 PM PST...DOPPLER RADAR INDICATED A SEVERE THUNDERSTORM
  CAPABLE OF PRODUCING DAMAGING WINDS IN EXCESS OF 60 MPH. THIS STORM
  WAS LOCATED NEAR MCKINLEYVILLE...OR 9 MILES NORTH OF EUREKA...AND
  MOVING NORTHEAST AT 25 MPH. PENNY SIZE HAIL MAY ALSO ACCOMPANY THE
  DAMAGING WINDS.

* LOCATIONS IMPACTED INCLUDE...
  ARCATA...MCKINLEYVILLE...WESTHAVEN-MOONSTONE...
  ARCATA AIRPORT AND FIELDBROOK.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

SEVERE THUNDERSTORMS PRODUCE DAMAGING WINDS...DESTRUCTIVE HAIL...
DEADLY LIGHTNING AND VERY HEAVY RAIN. FOR YOUR PROTECTION...MOVE TO
AN INTERIOR ROOM ON THE LOWEST FLOOR OF YOUR HOME OR BUSINESS. HEAVY
RAINS FLOOD ROADS QUICKLY SO DO NOT DRIVE INTO AREAS WHERE WATER
COVERS THE ROAD.

TORRENTIAL RAINFALL IS ALSO OCCURRING WITH THIS STORM...AND MAY LEAD
TO FLASH FLOODING. DO NOT DRIVE YOUR VEHICLE THROUGH FLOODED
ROADWAYS.

&&

LAT...LON 4093 12413 4101 12411 4110 12400 4093 12385
      4086 12413 4089 12414 4089 12415 4090 12414
      4090 12415
TIME...MOT...LOC 2008Z 236DEG 23KT 4092 12410 

$$

BC
2 follow-up statements
293 
WWUS56 KEKA 102020
SVSEKA

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE EUREKA
1220 PM PST THU DEC 10 2015

CAC023-102030-
/O.CON.KEKA.SV.W.0005.000000T0000Z-151210T2030Z/
HUMBOLDT CA-
1220 PM PST THU DEC 10 2015

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 1230 PM PST
FOR CENTRAL HUMBOLDT COUNTY...

AT 1219 PM PST...DOPPLER RADAR INDICATED A SEVERE THUNDERSTORM
CAPABLE OF PRODUCING DAMAGING WINDS IN EXCESS OF 60 MPH. THIS STORM
WAS LOCATED 3 MILES EAST OF MCKINLEYVILLE...MOVING NORTHEAST AT 25
MPH. PENNY SIZE HAIL MAY ALSO ACCOMPANY THE DAMAGING WINDS.

LOCATIONS IMPACTED INCLUDE...
FIELDBROOK. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

SEVERE THUNDERSTORMS PRODUCE DAMAGING WINDS...DESTRUCTIVE HAIL...
DEADLY LIGHTNING AND VERY HEAVY RAIN. FOR YOUR PROTECTION MOVE TO AN
INTERIOR ROOM ON THE LOWEST FLOOR OF YOUR HOME OR BUSINESS. HEAVY
RAINS FLOOD ROADS QUICKLY SO DO NOT DRIVE INTO AREAS WHERE WATER
COVERS THE ROAD.

TORRENTIAL RAINFALL IS ALSO OCCURRING WITH THIS STORM. DO NOT DRIVE
YOUR VEHICLE THROUGH FLOODED ROADWAYS.

&&

LAT...LON 4094 12408 4099 12407 4106 12398 4094 12388
      4090 12404 4091 12407
TIME...MOT...LOC 2019Z 236DEG 23KT 4096 12402 

$$

BC
726 
WWUS56 KEKA 102028
SVSEKA

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE EUREKA
1228 PM PST THU DEC 10 2015

CAC023-102037-
/O.EXP.KEKA.SV.W.0005.000000T0000Z-151210T2030Z/
HUMBOLDT CA-
1228 PM PST THU DEC 10 2015

...THE SEVERE THUNDERSTORM WARNING FOR CENTRAL HUMBOLDT COUNTY WILL
EXPIRE AT 1230 PM PST...
        
THE STORM WHICH PROMPTED THE WARNING HAS WEAKENED BELOW SEVERE LIMITS
AND EXITED THE WARNED AREA. THEREFORE THE WARNING WILL BE ALLOWED TO
EXPIRE. HOWEVER PEA SIZED HAIL...GUSTY WINDS AND BRIEF HEAVY RAIN
ARE STILL POSSIBLE WITH THIS THUNDERSTORM.

LAT...LON 4094 12408 4099 12407 4106 12398 4094 12388
      4090 12404 4091 12407
TIME...MOT...LOC 2026Z 236DEG 23KT 4096 12402 

$$

BC

The office that day

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

IssuedProductOfficeCountiesLasted
Dec 9, 11:23 PM PSTSpecial Marine WarningEKA82 min
Dec 10, 1:30 AM PSTAreal Flood AdvisoryEKAHumboldt, Mendocino, Trinity3 hr
Dec 10, 3:03 AM PSTHazardous Seas WarningEKA54 hr
Dec 10, 4:55 AM PSTSpecial Weather StatementEKAHumboldt35 min
Dec 10, 4:58 AM PSTSpecial Weather StatementEKADel Norte32 min
Dec 10, 5:31 AM PSTSpecial Weather StatementEKAHumboldt44 min
Dec 10, 7:41 AM PSTSpecial Weather StatementEKADel Norte34 min
Dec 10, 7:59 AM PSTSpecial Weather StatementEKA16 min
Dec 10, 8:17 AM PSTSpecial Weather StatementEKADel Norte13 min
Dec 10, 8:41 AM PSTSmall Craft AdvisoryEKA36 hr
Dec 10, 11:30 AM PSTSpecial Weather StatementEKADel Norte30 min
Dec 10, 11:38 AM PSTSpecial Weather StatementEKAMendocino22 min
Dec 10, 11:56 AM PSTSpecial Weather StatementEKAHumboldt19 min
Dec 10, 12:00 PM PSTSpecial Weather StatementEKADel Norte15 min
Dec 10, 12:03 PM PSTSpecial Weather StatementEKA42 min
Dec 10, 12:31 PM PSTSpecial Marine WarningEKA59 min
Dec 10, 12:35 PM PSTSpecial Weather StatementEKAHumboldt25 min
Dec 10, 12:50 PM PSTSpecial Weather StatementEKAHumboldt25 min
Dec 10, 2:47 PM PSTSpecial Weather StatementEKAMendocino13 min

Nearby

Severe Thunderstorm Warnings in California, 2015Every severe thunderstorm warning in 2015

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.