Alert archive / California / Winter Storm Warnings in 2017

Winter Storm Warning 7, NWS Eureka, CA

November 16, 2017Del Norte County, Humboldt County, California

NWS Eureka, CA issued this winter storm warning at Nov 16, 2017, 3:20 PM PST for Del Norte County, Humboldt County, California. It took effect at Nov 16, 2017, 4:00 PM PST. It was in force for 50 min. No storm report in the archive falls inside the area while it was in force.

The area

The counties it named.

The facts

Issued
Nov 16, 2017, 3:20 PM PST (23:20 UTC)
In effect from
Nov 16, 2017, 4:00 PM PST
Expired
Nov 16, 2017, 4:50 PM PST
In force
50 min
Issued by
NWS Eureka, CA

Counties Del Norte County, CA, Humboldt County, CA

The radar

The Eureka (Bunker Hill) radar (KBHX), 86 km from the middle of the area, began a volume at 23:20 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, 11.3 hours before the alert went out and 158 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 2017-11-16Temperature 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 2017-11-16The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 10 square meters per square second.1939587897117136Sfc1 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
757 m above ground
0-6 km bulk shear
101 kt
0-1 km storm-relative helicity
10 m²/s²
0-3 km storm-relative helicity
248 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

926 
WWUS46 KEKA 162320
WSWEKA

URGENT - WINTER WEATHER MESSAGE
National Weather Service Eureka CA
320 PM PST Thu Nov 16 2017

CAZ102-105-170730-
/O.NEW.KEKA.WS.W.0001.171117T0000Z-171117T1200Z/
Del Norte Interior-Northern Humboldt Interior-
320 PM PST Thu Nov 16 2017

...WINTER STORM WARNING IN EFFECT UNTIL 4 AM FRIDAY...

* WHAT...Heavy wet snow expected. Plan on difficult travel 
  conditions. Total wet snow accumulations of up to two inches, 
  with localized amounts up to 8 inches, are expected.

* WHERE...Del Norte Interior and Northern Humboldt Interior 
  County.

* WHEN...4 PM today to 4 AM Friday.

* ADDITIONAL DETAILS...Look for significant reductions in 
  visibility at times.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Winter Storm Warning for wet snow means severe winter weather
conditions are expected. If you must travel, keep an extra
flashlight, food and water in your vehicle in case of an
emergency. If driving, slow down. Allow extra time and be
prepared for changing conditions. Check the latest forecasts and
call 1-800-427-7623 for current road conditions and chain
requirements before travelling. Be alert for rock slides in
mountainous terrain.

For a detailed view of the hazard area visit:
http://www.wrh.noaa.gov/map/?wfo=eka

$$

CAZ107-108-170730-
/O.NEW.KEKA.WW.Y.0001.171117T0000Z-171117T1200Z/
Northern Trinity-Southern Trinity-
320 PM PST Thu Nov 16 2017

...WINTER WEATHER ADVISORY IN EFFECT UNTIL 4 AM FRIDAY...

* WHAT...Snow expected. Plan on slippery road conditions, 
  including during the evening commute. Total snow accumulations 
  of up to two inches, with localized amounts up to 5 inches, 
  are expected.

* WHERE...Northern Trinity and Southern Trinity County.

* WHEN...4 PM today to 4 AM Friday.

* ADDITIONAL DETAILS...Look for reduced visibilities at times.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Winter Weather Advisory for snow means periods of snow will
cause primarily travel difficulties. Be prepared for snow covered
roads and limited visibilities, and use caution while driving. 

For a detailed view of the hazard area visit:
http://www.wrh.noaa.gov/map/?wfo=eka

$$
2 follow-up statements
418 
WWUS46 KEKA 162355 CCA
WSWEKA

URGENT - WINTER WEATHER MESSAGE...CORRECTED
National Weather Service Eureka CA
355 PM PST Thu Nov 16 2017

CAZ102-105-170730-
/O.COR.KEKA.WS.W.0001.171117T0000Z-171117T1200Z/
Del Norte Interior-Northern Humboldt Interior-
355 PM PST Thu Nov 16 2017

...WINTER STORM WARNING IN EFFECT UNTIL 4 AM FRIDAY FOR ELEVATIONS
ABOVE 3500 FEET...

* WHAT...Heavy wet snow expected. Plan on difficult travel 
  conditions. Total wet snow accumulations of up to two inches, 
  with localized amounts up to 8 inches, are expected.

* WHERE...Del Norte Interior and Northern Humboldt Interior County
  above 3500 feet.

* WHEN...4 PM today to 4 AM Friday.

* ADDITIONAL DETAILS...Look for significant reductions in 
  visibility at times.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Winter Storm Warning for wet snow means severe winter weather
conditions are expected. If you must travel, keep an extra
flashlight, food and water in your vehicle in case of an
emergency. If driving, slow down. Allow extra time and be
prepared for changing conditions. Check the latest forecasts and
call 1-800-427-7623 for current road conditions and chain
requirements before travailing. Be alert for rock slides in
mountainous terrain.

For a detailed view of the hazard area visit:
http://www.wrh.noaa.gov/map/?wfo=eka

$$

CAZ107-108-170730-
/O.COR.KEKA.WW.Y.0001.171117T0000Z-171117T1200Z/
Northern Trinity-Southern Trinity-
355 PM PST Thu Nov 16 2017

...WINTER WEATHER ADVISORY IN EFFECT UNTIL 4 AM FRIDAY FOR
ELEVATIONS ABOVE 3500 FEET...

* WHAT...Snow expected. Plan on slippery road conditions, 
  including during the evening commute. Total snow accumulations 
  of up to two inches, with localized amounts up to 5 inches, 
  are expected.

* WHERE...Trinity County above 3500 feet.

* WHEN...4 PM today to 4 AM Friday.

* ADDITIONAL DETAILS...Look for reduced visibilities at times.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Winter Weather Advisory for snow means periods of snow will
cause primarily travel difficulties. Be prepared for snow covered
roads and limited visibilities, and use caution while driving. 

For a detailed view of the hazard area visit:
http://www.wrh.noaa.gov/map/?wfo=eka

$$
472 
WWUS46 KEKA 170050
WSWEKA

URGENT - WINTER WEATHER MESSAGE
National Weather Service Eureka CA
450 PM PST Thu Nov 16 2017

CAZ102-105-170900-
/O.CAN.KEKA.WS.W.0001.000000T0000Z-171117T1200Z/
/O.EXA.KEKA.WW.Y.0001.000000T0000Z-171117T1200Z/
Del Norte Interior-Northern Humboldt Interior-
450 PM PST Thu Nov 16 2017

...WINTER WEATHER ADVISORY IN EFFECT UNTIL 4 AM PST FRIDAY ABOVE
3500 FEET...
...WINTER STORM WARNING IS CANCELLED...

* WHAT...Snow occurring. Plan on slippery road conditions,
  including during the evening commute. Additional snow
  accumulations of 2 to 4 inches, with localized amounts up to 7
  inches, are expected.

* WHERE...Del Norte Interior and Northern Humboldt Interior 
  County.

* WHEN...Until 4 AM Friday.

* ADDITIONAL DETAILS...Look for reduced visibilities at times with
  heavy snow showers.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Winter Weather Advisory for snow means periods of snow will
cause primarily travel difficulties. Be prepared for snow covered
roads and limited visibilities, and use caution while driving. 

For a detailed view of the hazard area visit:
http://www.wrh.noaa.gov/map/?wfo=eka

&&

$$

CAZ107-108-170900-
/O.CON.KEKA.WW.Y.0001.000000T0000Z-171117T1200Z/
Northern Trinity-Southern Trinity-
450 PM PST Thu Nov 16 2017

...WINTER WEATHER ADVISORY REMAINS IN EFFECT UNTIL 4 AM PST
FRIDAY ABOVE 3500 FEET...

* WHAT...Snow occurring. Plan on slippery road conditions, 
  including during the evening commute. Additional snow 
  accumulations of up to 2 inches, with localized amounts up to 
  4 inches, are expected.

* WHERE...Northern Trinity and Southern Trinity County.

* WHEN...Until 4 AM Friday.

* ADDITIONAL DETAILS...Look for reduced visibilities at times with
  heavy snow showers.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Winter Weather Advisory for snow means periods of snow will
cause primarily travel difficulties. Be prepared for snow covered
roads and limited visibilities, and use caution while driving. 

For a detailed view of the hazard area visit:
http://www.wrh.noaa.gov/map/?wfo=eka

&&

$$

The office that day

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

IssuedProductOfficeCountiesLasted
Nov 15, 7:05 PM PSTGale WarningEKA3 hr
Nov 15, 7:05 PM PSTSmall Craft AdvisoryEKA20 hr
Nov 16, 8:14 AM PSTSmall Craft AdvisoryEKA7 hr
Nov 16, 3:20 PM PSTWinter Weather AdvisoryEKADel Norte, Humboldt, Trinity12 hr

Nearby

Winter Storm Warnings in California, 2017Every winter storm 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.