Alert archive / California / Severe Thunderstorm Warnings in 2009

Severe Thunderstorm Warning 11, NWS Eureka, CA

June 3, 2009Mendocino County, California

NWS Eureka, CA issued this severe thunderstorm warning at Jun 3, 2009, 4:00 PM PDT for Mendocino County, California. It was in force for 18 min. 1 report 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
Jun 3, 2009, 4:00 PM PDT (23:00 UTC)
Expired
Jun 3, 2009, 4:18 PM PDT
In force
18 min
Issued by
NWS Eureka, CA
Area
Storm-based polygon

County Mendocino County, CA

The radar

The Eureka (Bunker Hill) radar (KBHX), 133 km from the middle of the area, began a volume at 23:02 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
Jun 3, 4:20 PM PDTHAIL 0.8815 N Potter Valley, CAHARTSTONE BIBLE CONFERENCE NORTH OF POTTER VALLEY REPORTED DIME-NICKEL SIZE HAIL IN THUNDERSTORM.

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

Did it verify

Not verified. The Iowa Environmental Mesonet's Cow found no qualifying storm report inside this severe thunderstorm warning while it was in force. That is not proof nothing happened: reports are thin where few people live.

Cow counts a report within 15 km of the polygon while the warning was in force: a tornado for a tornado warning; hail of 1 inch or more, a gust of 58 mph or more or wind damage for a severe thunderstorm warning; a flash flood report for a flash flood warning.

The nearest sounding before it

Oakland, CA (KOAK), launched 12:00Z, 11.0 hours before the alert went out and 229 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 2009-06-03Temperature 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, Oakland, CA at 12:00Z on 2009-06-03The 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
758 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
175 m²/s²
Significant tornado parameter
0.0
Supercell composite
1.1

Open this sounding in Storm Lab

The text

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

000 
WUUS56 KEKA 032300
SVREKA
CAC045-032330-
/O.NEW.KEKA.SV.W.0011.090603T2300Z-090603T2330Z/

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE EUREKA CA
400 PM PDT WED JUN 3 2009

THE NATIONAL WEATHER SERVICE IN EUREKA HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  CENTRAL MENDOCINO COUNTY IN NORTHWEST CALIFORNIA...

* UNTIL 430 PM PDT

* AT 359 PM PDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  SEVERE THUNDERSTORM CAPABLE OF PRODUCING QUARTER SIZE HAIL.  THIS
  STORM WAS LOCATED 18 MILES SOUTHEAST OF DOS RIOS...OR 12 MILES
  NORTHEAST OF WILLITS...AND MOVING NORTH 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 3974 12338 3977 12307 3944 12310 3943 12324
TIME...MOT...LOC 2300Z 172DEG 16KT 3950 12317

$$

BK
1 follow-up statement
000 
WWUS56 KEKA 032318
SVSEKA

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE EUREKA CA
418 PM PDT WED JUN 3 2009

CAC045-032327-
/O.CAN.KEKA.SV.W.0011.000000T0000Z-090603T2330Z/
MENDOCINO CA-
418 PM PDT WED JUN 3 2009

...THE SEVERE THUNDERSTORM WARNING FOR CENTRAL MENDOCINO COUNTY IS
CANCELLED...

THE THUNDERSTORM THAT PROMPTED THE WARNING HAS WEAKENED. 
THUNDERSTORM ACTIVITY WILL CONTINUE INTO THE EVENING HOURS.

LAT...LON 3974 12338 3977 12307 3944 12310 3943 12324
TIME...MOT...LOC 2317Z 172DEG 16KT 3957 12318

$$

BK

What forecasters said that day

The local office's own words before this severe thunderstorm warning went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Eureka, CA wrote its last area forecast discussion before this severe thunderstorm warning went out at Jun 3, 2:09 PM PDT, 1 hour 51 minutes earlier.

Area forecast discussion, Jun 3, 2:09 PM PDT, 1 hour 51 minutes before
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE EUREKA CA
210 PM PDT WED JUNE 03 2009

SYNOPSIS...AN AREA OF LOW PRESSURE ALONG THE WEST COAST WILL
CONTINUE TO PRODUCE SHOWERS AND ISOLATED THUNDERSTORMS TO NORTHWEST
CALIFORNIA THROUGH THE END OF THE WEEK.
&&

.SHORT TERM...TONIGHT THROUGH SATURDAY...SATELLITE AND RADAR IMAGERY
SHOW CONVECTION DEVELOPING THIS AFTERNOON. EXPECT SCT SHRA AND ISOLD
TSTMS TO CONTINUE TO DEVELOP OVER THE REGION AND PROPAGATE TO THE NW
ACROSS THE CWA AS QUASI STATIONARY UPPER LOW REMAINS OFF THE COAST.
STABILITY INDICES SHOW SLIGHT POTENTIAL FOR LARGE HAIL AND DAMAGING
WINDS WITH STORMS THIS AFTERNOON...SO WILL CONTINUE TO MONITOR RADAR
TRENDS THROUGH THIS EVENING. EXPECT CONVECTION TO PEAK BY EARLY THIS
EVENING AS A MINOR SHORT WAVE ROTATES AROUND THE PARENT LOW WITH
SHOWERS CONTINUING THROUGH THE NIGHT IN THE UNSTABLE ATMOSPHERE. A
SERIES OF VORT MAXES WILL ROTATE AROUND THE LOW AND COMBINE WITH A
RELATIVELY DEEP MOIST LAYER TO CONTINUE THE THREAT OF CONVECTION
THU. MODELS IN GOOD AGREEMENT ON UPPER LOW DRIFTING ONSHORE FRI WITH
AFTERNOON CONVECTION EXPECTED AGAIN. THE THREAT FOR TSTMS WILL
DIMINISH SAT AS THE UPPER LOW MOVES E OF THE REGION. BC

&&

.LONG TERM (SATURDAY NIGHT THROUGH WEDNESDAY)...THE MEDIUM RANGE
MODELS CONTINUE TO SHOW SOME CHANGES IN HOW THE UPPER LOW IS HANDLED
THROUGH THE INITIAL PART OF THE EXTENDED. HOWEVER THE GENERAL IDEA
OF MOVING THE LOW ONSHORE AND DEVELOPING SPLIT FLOW ALOFT IS
MAINTAINED. THE LATEST ITERATION BRINGS THE LOW ONSHORE SOUTH OF
POINT CONCEPTION EARLY SATURDAY EVENING...AND INLAND ACROSS LAS
VEGAS BY 12Z SUNDAY. THE SOUTHERN BRANCH OF THE SPLIT FLOW PUSHES A
LOW WEST TO THE OFFSHORE WATERS EARLY NEXT WEEK. NORTHERN CALIFORNIA
WILL REMAIN IN LIGHT NORTHERLY FLOW WITH LINGERING MOISTURE THROUGH
MONDAY...WITH A WEAK SHORTWAVE FORECAST BY THE GFS TO BRUSH THE CWA
LATE MONDAY INTO TUESDAY...FOLLOWED BY A SIMILAR WEAK SYSTEM EARLY
WEDNESDAY. CILIBERTI

&&

.MARINE...LIGHT WINDS AND LOW SEAS WILL PREVAIL THROUGH THE WEEK.
THE SEAS WILL CONTAIN A MIX OF SHORT PERIOD NW SWELL AND LONG PERIOD
SOUTH TO SW SWELL...WITH SIG WAVE HEIGHTS NEAR 3 FEET. ISOLATED
THUNDERSTORMS WILL PERSIST THROUGH FRIDAY...BRINGING OCCASIONAL
CLOUD-TO-WATER LIGHTNING STRIKES...HEAVY RAIN...HAIL AND SUDDEN
BURSTS OF WIND.

&&

.AVIATION...CONTINUED ADVECTION OF MOIST AIR AND
INSTABILITY...ASSOCIATED WITH A LOW PRESSURE SYSTEM CENTERED OFF THE
CENTRAL COAST...WILL PRODUCE SHOWERS AND THE THREAT OF THUNDERSTORMS
ACROSS THE REGION. THE STORMS MAY PRODUCE HAIL...HEAVY RAIN AS WELL
AS STRONG AND ABRUPT WINDS. THESE ARE STANDARD FLIGHT HAZARDS
ASSOCIATED WITH CONVECTION...AND ARE THE PRIMARY RISK TO AVIATION.
AS TYPICAL...POCKETS OF IFR TO MVFR CONDITIONS WILL CONTINUE ALONG
THE COASTAL STRIP. ASHFORD

&&

.EKA WATCHES/WARNINGS/ADVISORIES...

NONE.

&&

VISIT US AT HTTP://WWW.WEATHER.GOV/EUREKA
Hazardous weather outlook, Jun 3, 5:18 AM PDT, 10 hours 42 minutes before
HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE EUREKA CA
518 AM PDT WED JUN 3 2009

CAZ001>004-076-041230-
REDWOOD COAST-MENDOCINO COAST-NORTH COAST INTERIOR-
UPPER TRINITY RIVER-MENDOCINO INTERIOR-
518 AM PDT WED JUN 3 2009

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF NORTHWEST
CALIFORNIA.

.DAY ONE...TODAY AND TONIGHT

THUNDERSTORM ACTIVITY WILL CONTINUE ACROSS NORTHWEST CALIFORNIA
TODAY AND TONIGHT. STORMS WILL BE ACCOMPANIED BY LIGHTNING...HAIL
...GUSTY WINDS AND POTENTIALLY HEAVY RAIN. ALTHOUGH A MAJORITY OF
THE STORMS ARE NOT EXPECTED TO BECOME SEVERE...THE THREAT OF
ISOLATED STORMS CONTAINING DAMAGING WINDS OR HAIL IS POSSIBLE.

.DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY

THUNDERSTORM ACTIVITY WILL CONTINUE ACROSS NORTHWEST CALIFORNIA
THROUGH THURSDAY. STORMS WILL BE ACCOMPANIED BY LIGHTNING...HAIL
...GUSTY WINDS AND POTENTIALLY HEAVY RAIN. ALTHOUGH A MAJORITY OF
THE STORMS ARE NOT EXPECTED TO BECOME SEVERE...THE THREAT OF
ISOLATED STORMS CONTAINING DAMAGING WINDS OR HAIL IS POSSIBLE.

.SPOTTER INFORMATION STATEMENT...

WEATHER SPOTTERS ARE ENCOURAGED TO REPORT SIGNIFICANT WEATHER
CONDITIONS SUCH AS LIGHTNING...STRONG WINDS...HAIL OR FLOODING TO
THEIR LOCAL NATIONAL WEATHER SERVICE OFFICE.

In the hours before

Special weather statement, Jun 3, 2:47 PM PDT, 1 hour 13 minutes before
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE EUREKA CA
247 PM PDT WED JUN 3 2009

CAZ003-004-032230-
TRINITY CA-HUMBOLDT CA-
247 PM PDT WED JUN 3 2009

THE NATIONAL WEATHER SERVICE IN EUREKA HAS ISSUED A

SIGNIFICANT WEATHER ADVISORY FOR...
  SOUTHEASTERN HUMBOLDT COUNTY IN NORTHWEST CALIFORNIA
  SOUTHWESTERN TRINITY COUNTY IN NORTHWEST CALIFORNIA

UNTIL 330 PM PDT

AT 245 PM PDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
STRONG THUNDERSTORM 6 MILES SOUTHEAST OF RUTH..MOVING NORTHWEST AT 10
MPH.

HAIL UP TO ONE-HALF INCH IN DIAMETER AND WIND GUSTS UP TO 40 MPH ARE
EXPECTED WITH THIS STORM...ALONG WITH HEAVY RAIN AND FREQUENT
DANGEROUS LIGHTNING.

LOCATIONS IMPACTED INCLUDE...
   RUTH...

IF THREATENING WEATHER APPROACHES YOUR AREA...TAKE SHELTER IN A
STURDY BUILDING.

LAT...LON 4035 12365 4050 12339 4020 12316 4009 12335
TIME...MOT...LOC 2147Z 145DEG 11KT 4022 12333

BC
Special weather statement, Jun 3, 3:04 PM PDT, 56 minutes before
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE EUREKA CA
304 PM PDT WED JUN 3 2009

CAZ003-004-076-032300-
TRINITY CA-MENDOCINO CA-
304 PM PDT WED JUN 3 2009

THE NATIONAL WEATHER SERVICE IN EUREKA HAS ISSUED A

SIGNIFICANT WEATHER ADVISORY FOR...
  NORTHEASTERN MENDOCINO COUNTY IN NORTHWEST CALIFORNIA
  SOUTH CENTRAL TRINITY COUNTY IN NORTHWEST CALIFORNIA

UNTIL 400 PM PDT

AT 303 PM PDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
STRONG THUNDERSTORM 11 MILES EAST OF COVELO..MOVING NORTH AT 15 MPH.

HAIL UP TO ONE-HALF INCH IN DIAMETER AND WIND GUSTS UP TO 40 MPH ARE
EXPECTED WITH THIS STORM...ALONG WITH HEAVY RAIN AND FREQUENT
DANGEROUS LIGHTNING.

LOCATIONS IMPACTED INCLUDE...
  RURAL NORTHEASTERN MENDOCINO COUNTY...
  RURAL SOUTHERN TRINITY COUNTY...

IF THREATENING WEATHER APPROACHES YOUR AREA...TAKE SHELTER IN A
STURDY BUILDING.

LAT...LON 3967 12312 4001 12329 4008 12298 3987 12293
      3984 12294 3982 12293 3975 12292 3975 12291
      3972 12290
TIME...MOT...LOC 2204Z 165DEG 12KT 3978 12304

BC
Special weather statement, Jun 3, 3:51 PM PDT, 9 minutes before
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE EUREKA CA
351 PM PDT WED JUN 3 2009

CAZ003-032330-
HUMBOLDT CA-
351 PM PDT WED JUN 3 2009

THE NATIONAL WEATHER SERVICE IN EUREKA HAS ISSUED A

SIGNIFICANT WEATHER ADVISORY FOR...
  CENTRAL HUMBOLDT COUNTY IN NORTHWEST CALIFORNIA

UNTIL 430 PM PDT

AT 350 PM PDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
STRONG THUNDERSTORM 12 MILES NORTH OF DINSMORE..MOVING NORTHWEST AT
10 MPH.

HAIL UP TO ONE-HALF INCH IN DIAMETER AND WIND GUSTS UP TO 50 MPH ARE
EXPECTED WITH THIS STORM...ALONG WITH HEAVY RAIN AND FREQUENT
DANGEROUS LIGHTNING.

LOCATIONS IMPACTED INCLUDE...
  RURAL CENTRAL HUMBOLDT COUNTY...

IF THREATENING WEATHER APPROACHES YOUR AREA...TAKE SHELTER IN A
STURDY BUILDING.

LAT...LON 4064 12394 4081 12380 4068 12362 4059 12358
      4056 12361
TIME...MOT...LOC 2251Z 126DEG 11KT 4064 12368

BC

The office that day

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

IssuedProductOfficeCountiesLasted
Jun 2, 6:15 PM PDTSpecial Weather StatementEKAMendocino45 min
Jun 2, 6:32 PM PDTSevere Thunderstorm WarningEKAMendocino28 min
Jun 2, 7:15 PM PDTSpecial Weather StatementEKASiskiyou45 min
Jun 3, 2:43 PM PDTAreal Flood AdvisoryEKAMendocino3 hr
Jun 3, 2:47 PM PDTSpecial Weather StatementEKATrinity43 min
Jun 3, 3:04 PM PDTSpecial Weather StatementEKA56 min
Jun 3, 3:21 PM PDTSevere Thunderstorm WarningEKAHumboldt, Trinity24 min
Jun 3, 3:28 PM PDTSevere Thunderstorm WarningEKAMendocino, Trinity32 min
Jun 3, 3:44 PM PDTSevere Thunderstorm WarningEKAHumboldt, Trinity46 min
Jun 3, 3:51 PM PDTSpecial Weather StatementEKAHumboldt39 min
Jun 3, 4:05 PM PDTSevere Thunderstorm WarningEKATrinity25 min
Jun 3, 4:20 PM PDTSevere Thunderstorm WarningEKAHumboldt25 min
Jun 3, 4:26 PM PDTSpecial Weather StatementEKAHumboldt19 min
Jun 3, 4:36 PM PDTSpecial Weather StatementEKAMendocino24 min
Jun 3, 4:42 PM PDTSpecial Weather StatementEKAMendocino33 min
Jun 3, 4:47 PM PDTSevere Thunderstorm WarningEKAHumboldt, Trinity13 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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.