Alert archive / California / Winter Storm Warnings in 2020

Winter Storm Warning 5, NWS Eureka, CA

December 24, 2020Trinity County, California

NWS Eureka, CA issued this winter storm warning at Dec 24, 2020, 3:11 AM PST for Trinity County, California. It took effect at Dec 25, 2020, 10:00 AM PST. It was in force for 17 hr. No storm report in the archive falls inside the area while it was in force.

The area

The counties it named.

The facts

Issued
Dec 24, 2020, 3:11 AM PST (11:11 UTC)
In effect from
Dec 25, 2020, 10:00 AM PST
Expired
Dec 26, 2020, 2:47 AM PST
In force
17 hr
Issued by
NWS Eureka, CA

County Trinity County, CA

The radar

The Eureka (Bunker Hill) radar (KBHX), 101 km from the middle of the area, began a volume at 11:13 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, 11.2 hours before the alert went out and 193 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 2020-12-24Temperature 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 00:00Z on 2020-12-24The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 44 square meters per square second.1939Sfc1 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
2754 m above ground
0-6 km bulk shear
21 kt
0-1 km storm-relative helicity
44 m²/s²
0-3 km storm-relative helicity
85 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

910 
WWUS46 KEKA 241111
WSWEKA

URGENT - WINTER WEATHER MESSAGE
National Weather Service Eureka CA
311 AM PST Thu Dec 24 2020

...HEAVY MOUNTAIN SNOW EXPECTED CHRISTMAS DAY ABOVE 3500 FEET...

.Light precipitation is forecast to spread across the region late
Friday morning and increase in intensity during the afternoon and
evening. A cold airmass will favor snow across Trinity County. 
The heaviest snowfall totals will occur across the Trinity Alps, 
but snow will also be possible across the eastern valleys around 
highway pass level.

CAZ107-108-241915-
/O.UPG.KEKA.WS.A.0005.201225T1800Z-201226T1800Z/
/O.NEW.KEKA.WS.W.0005.201225T1800Z-201226T1800Z/
Northern Trinity-Southern Trinity-
311 AM PST Thu Dec 24 2020

...WINTER STORM WARNING IN EFFECT FROM 10 AM FRIDAY TO 10 AM PST
SATURDAY ABOVE 3500 FEET...

* WHAT...Heavy snow expected. Total snow accumulations up to 15 
  inches at Scott Mountain pass. Three to six inches are possible 
  around Trinity Center at 2500 feet. An inch or less is expected 
  at Weaverville, Douglas City and Hayfork. 

* WHERE...Northern Trinity and Southern Trinity Counties.

* WHEN...From 10 AM Friday to 10 AM PST Saturday.

* IMPACTS...Travel could be very difficult to impossible at times.
  The hazardous conditions will be impacted on highway three at
  Scott Mountain pass.
  

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If you must travel, keep an extra flashlight, food, and water in
your vehicle in case of an emergency. 

The latest road conditions for the state of California can be
obtained by calling 1-800-GAS-ROAD.

&&

$$
7 follow-up statements
261 
WWUS46 KEKA 241900
WSWEKA

URGENT - WINTER WEATHER MESSAGE
National Weather Service Eureka CA
1100 AM PST Thu Dec 24 2020

...HEAVY MOUNTAIN SNOW EXPECTED CHRISTMAS DAY ABOVE 3500 FEET...

.Light precipitation is forecast to spread across the region late
Friday morning and increase in intensity during the afternoon and
evening. A cold airmass will favor snow across Trinity County.
The heaviest snowfall totals will occur across the Trinity Alps,
but snow will also be possible across the eastern valleys around
highway pass level.

CAZ107-108-250400-
/O.CON.KEKA.WS.W.0005.201225T1800Z-201226T1800Z/
Northern Trinity-Southern Trinity-
1100 AM PST Thu Dec 24 2020

...WINTER STORM WARNING REMAINS IN EFFECT FROM 10 AM FRIDAY TO
10 AM PST SATURDAY ABOVE 3500 FEET...

* WHAT...Heavy snow expected. Total snow accumulations up to 15 
  inches at Scott Mountain pass. Three to six inches are 
  possible around Trinity Center at 2500 feet. An inch or less 
  is expected at Weaverville, Douglas City and Hayfork.

* WHERE...Northern Trinity and Southern Trinity Counties.

* WHEN...From 10 AM Friday to 10 AM PST Saturday.

* IMPACTS...Travel could be very difficult to impossible at 
  times. The hazardous conditions will be impacted on highway 
  three at Scott Mountain pass.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If you must travel, keep an extra flashlight, food, and water in
your vehicle in case of an emergency. Prepare for possible power
outages. 

The latest road conditions for the state of California can be
obtained by calling 1-800-GAS-ROAD.

&&

$$
174 
WWUS46 KEKA 250103
WSWEKA

URGENT - WINTER WEATHER MESSAGE
National Weather Service Eureka CA
503 PM PST Thu Dec 24 2020

...HEAVY MOUNTAIN SNOW EXPECTED CHRISTMAS DAY ABOVE 2500 FEET...

.Precipitation is forecast to spread across the region Friday 
morning and increase in intensity during the afternoon and 
evening. A cold airmass will favor snow across Trinity County. The
heaviest snowfall totals will occur across the Trinity Alps, but 
snow will also be possible at highway pass level.

CAZ107-108-250915-
/O.CON.KEKA.WS.W.0005.201225T1800Z-201226T1800Z/
Northern Trinity-Southern Trinity-
503 PM PST Thu Dec 24 2020

...WINTER STORM WARNING REMAINS IN EFFECT FROM 10 AM FRIDAY TO
10 AM PST SATURDAY ABOVE 2500 FEET...

* WHAT...Heavy snow expected above 2500 feet. Snow accumulations
  in excess of a foot at Scott Mountain Summit on Highway 3. Six
  inches at Oregon Mountain and Buckhorn Summit on Highway 299.
  Three to six inches possible at Trinity Center. Around an inch
  at Weaverville.

* WHERE...Southern Trinity and Northern Trinity Counties.

* WHEN...From 10 AM Friday to 10 AM PST Saturday.

* IMPACTS...Travel could be very difficult to impossible.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If you must travel, keep an extra flashlight, food, and water in
your vehicle in case of an emergency. 

The latest road conditions for the state of California can be
obtained by calling 1-800-GAS-ROAD.

&&

$$
122 
WWUS46 KEKA 250616
WSWEKA

URGENT - WINTER WEATHER MESSAGE
National Weather Service Eureka CA
1016 PM PST Thu Dec 24 2020

...HEAVY MOUNTAIN SNOW EXPECTED CHRISTMAS DAY ABOVE 2500 FEET...

.Precipitation is forecast to spread across the region Friday
morning and increase in intensity during the afternoon and
evening. A cold airmass will favor snow across Trinity County.
The heaviest snowfall totals will occur across the Trinity Alps,
but snow will also be possible at highway pass level.

CAZ107-108-251430-
/O.CON.KEKA.WS.W.0005.201225T1800Z-201226T1800Z/
Northern Trinity-Southern Trinity-
1016 PM PST Thu Dec 24 2020

...WINTER STORM WARNING REMAINS IN EFFECT FROM 10 AM FRIDAY TO
10 AM PST SATURDAY ABOVE 2500 FEET...

* WHAT...Heavy snow expected above 2500 feet. Snow accumulations 
  in excess of a foot at Scott Mountain Summit on Highway 3. Six 
  inches at Oregon Mountain and Buckhorn Summit on Highway 299. 
  Three to six inches possible at Trinity Center. Around an inch 
  at Weaverville.

* WHERE...Southern Trinity and Northern Trinity Counties.

* WHEN...From 10 AM Friday to 10 AM PST Saturday.

* IMPACTS...Travel could be very difficult to impossible.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If you must travel, keep an extra flashlight, food, and water in
your vehicle in case of an emergency. 

The latest road conditions for the state of California can be
obtained by calling 1-800-GAS-ROAD.

&&

$$
849 
WWUS46 KEKA 251109
WSWEKA

URGENT - WINTER WEATHER MESSAGE
National Weather Service Eureka CA
309 AM PST Fri Dec 25 2020

CAZ108-251215-
/O.CAN.KEKA.WS.W.0005.201225T1800Z-201226T1800Z/
Southern Trinity-
309 AM PST Fri Dec 25 2020

...WINTER STORM WARNING IS CANCELLED...

$$

CAZ107-251915-
/O.CON.KEKA.WS.W.0005.201225T1800Z-201226T1800Z/
Northern Trinity-
309 AM PST Fri Dec 25 2020

...WINTER STORM WARNING REMAINS IN EFFECT FROM 10 AM THIS MORNING
TO 10 AM PST SATURDAY ABOVE 2500 FEET...

* WHAT...Heavy snow expected above 2500 to 3500 feet. Total snow
  accumulations of up to 24 inches at Scott Mountain Pass on
  highway 3. Around 3 inches expected at Buckhorn Summit on
  Highway 299. 4 to 6 inches expected around Trinity Center. Less
  than an inch possible elsewhere at elevations around 2500 feet.
  

* WHERE...Northern Trinity County.

* WHEN...From 10 AM this morning to 10 AM PST Saturday.

* IMPACTS...Travel could be very difficult to impossible. The 
  hazardous conditions could impact the evening commute. Gusty 
  winds could bring down tree branches.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If you must travel, keep an extra flashlight, food, and water in
your vehicle in case of an emergency. 

The latest road conditions for the state of California can be
obtained by calling 1-800-GAS-ROAD.

&&

$$
220 
WWUS46 KEKA 251859
WSWEKA

URGENT - WINTER WEATHER MESSAGE
National Weather Service Eureka CA
1059 AM PST Fri Dec 25 2020

CAZ107-260400-
/O.CON.KEKA.WS.W.0005.000000T0000Z-201226T1800Z/
Northern Trinity-
1059 AM PST Fri Dec 25 2020

...WINTER STORM WARNING REMAINS IN EFFECT UNTIL 10 AM PST
SATURDAY ABOVE 2500 FEET...

* WHAT...Heavy snow expected above 2500 to 3500 feet. Total snow
  accumulations of up to 24 inches at Scott Mountain Pass on
  highway 3. Around 3 inches expected at Buckhorn Summit on
  Highway 299. 4 to 6 inches expected around Trinity Center.
  Around an inch possible elsewhere at elevations around 2500 
  feet.

* WHERE...Northern Trinity County.

* WHEN...Until 10 AM PST Saturday.

* IMPACTS...Travel could be very difficult to impossible. The 
  hazardous conditions could impact the evening commute. Gusty 
  winds could bring down tree branches.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If you must travel, keep an extra flashlight, food, and water in
your vehicle in case of an emergency. 

The latest road conditions for the state of California can be
obtained by calling 1-800-GAS-ROAD.

&&

$$
255 
WWUS46 KEKA 260345
WSWEKA

URGENT - WINTER WEATHER MESSAGE
National Weather Service Eureka CA
745 PM PST Fri Dec 25 2020


CAZ107-261145-
/O.CON.KEKA.WS.W.0005.000000T0000Z-201226T1800Z/
Northern Trinity-
745 PM PST Fri Dec 25 2020

...WINTER STORM WARNING REMAINS IN EFFECT UNTIL 10 AM PST
SATURDAY ABOVE 2500 FEET...

* WHAT...Heavy snow expected above 2500 to 3500 feet. Total snow
  accumulations of up to 24 inches at Scott Mountain Pass on
  highway 3. Around 3 inches expected at Buckhorn Summit on
  Highway 299.

* WHERE...Northern Trinity County.

* WHEN...Until 10 AM PST Saturday.

* IMPACTS...Travel could be very difficult to impossible.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If you must travel, keep an extra flashlight, food, and water in
your vehicle in case of an emergency. 

The latest road conditions for the state of California can be
obtained by calling 1-800-GAS-ROAD.

&&

$$
751 
WWUS46 KEKA 261047
WSWEKA

URGENT - WINTER WEATHER MESSAGE
National Weather Service Eureka CA
247 AM PST Sat Dec 26 2020

CAZ107-261800-
/O.CAN.KEKA.WS.W.0005.000000T0000Z-201226T1800Z/
/O.NEW.KEKA.WW.Y.0016.201226T1047Z-201226T1800Z/
Northern Trinity-
247 AM PST Sat Dec 26 2020

...WINTER WEATHER ADVISORY IN EFFECT UNTIL 10 AM PST THIS MORNING
ABOVE 3500 FEET...
...WINTER STORM WARNING IS CANCELLED...

* WHAT...Additional snow accumulation up to 2 inches expected 
  over Scott Mountain Pass this morning. 

* WHERE...Northern Trinity County.

* WHEN...Until 10 AM PST this morning.

* IMPACTS...Travel could be very difficult on highway 3 over Scott
  Mountain Pass.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Slow down and use caution while traveling. 

The latest road conditions for the state of California can be
obtained by calling 1-800-GAS-ROAD.

&&

$$

The office that day

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

IssuedProductOfficeCountiesLasted
Dec 24, 3:12 AM PSTWind AdvisoryEKADel Norte, Humboldt39 hr

Nearby

Winter Storm Warnings in California, 2020Every winter storm warning in 2020

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.