Alert archive / California / Winter Storm Warnings in 2024

Winter Storm Warning 10, NWS Eureka, CA

November 18, 2024Trinity County, California

NWS Eureka, CA issued this winter storm warning at Nov 18, 2024, 12:10 PM PST for Trinity County, California. It took effect at Nov 19, 2024, 4:00 PM PST. It was in force for 54 hr. 4 reports came from inside the area while it was in force.

The area

The counties it named, with what was reported inside it.

The facts

Issued
Nov 18, 2024, 12:10 PM PST (20:10 UTC)
In effect from
Nov 19, 2024, 4:00 PM PST
Expired
Nov 21, 2024, 10:00 PM PST
In force
54 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 20:11 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
Nov 20, 9:26 AM PSTSNOW 33 Wsw Lewiston, CA3 inches of snow reported near Lewiston at 1950 ft. Snow is still falling.
Nov 20, 9:40 AM PSTSNOW/ICE DMG6 Se Lewiston, CAJackknifed semitruck near Buckhorn Summit on Highway 299 blocking both lanes.
Nov 20, 9:57 AM PSTSNOW 125 Sw Douglas City, CACHP reports a vehicle stuck in about 1 foot of snow near Hayfork Summit.
Nov 20, 1:50 PM PSTSNOW 1310 Ne Weaverville, CA13 inches of snow reported as of 1:50 PM. Snow has transitioned to rain.

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 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 12:00Z on 2024-11-18Temperature 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°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Medford/Jackson, OR at 12:00Z on 2024-11-18The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 87 square meters per square second.1939587897117Sfc1 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
580 m above ground
0-6 km bulk shear
70 kt
0-1 km storm-relative helicity
87 m²/s²
0-3 km storm-relative helicity
125 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

855 
WWUS46 KEKA 182010
WSWEKA

URGENT - WINTER WEATHER MESSAGE
National Weather Service Eureka CA
1210 PM PST Mon Nov 18 2024

CAZ107-190415-
/O.UPG.KEKA.WS.A.0010.241120T0000Z-241121T0500Z/
/O.NEW.KEKA.WS.W.0010.241120T0000Z-241121T0500Z/
Northern Trinity-
Including Weaverville, Hwy 299-Buckhorn Summit, Hwy 3-Scott
Mountain, Hwy 299-Oregon Mountain, and Trinity Center
1210 PM PST Mon Nov 18 2024

...WINTER STORM WARNING IN EFFECT FROM 4 PM TUESDAY TO 9 PM PST 
WEDNESDAY ELEVATIONS ABOVE 2,000 FEET...

* WHAT...Heavy snow possible. Total snow accumulations between 5 and 
  10 inches possible above 2,000 feet, 1 to 3 feet possible above 
  4,000 feet. Winds could gust as high as 50 mph. Lowest snow levels 
  expected during Wednesday morning.

* WHERE...Northeastern Trinity.

* WHEN...From 4 PM Tuesday to 9 PM PST Wednesday.

* IMPACTS...Travel could be very difficult to impossible. Tire 
  chains may be necessary if travelling through mountain passes. 
  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 you are calling from can be obtained by calling 5 1 1.

&&

$$

CAZ108-190415-
/O.UPG.KEKA.WS.A.0010.241120T0000Z-241120T1200Z/
/O.NEW.KEKA.WS.W.0010.241120T0000Z-241120T1200Z/
Southern Trinity-
1210 PM PST Mon Nov 18 2024

...WINTER STORM WARNING IN EFFECT FROM 4 PM TUESDAY TO 4 AM PST 
WEDNESDAY...

* WHAT...Heavy snow possible. Total snow accumulations of 5 to 8 
  inches possible. Winds could gust as high as 50 mph.

* WHERE...Portions of southern Trinity to the east of Forest Glen 
  and Hyampom and above around 3500 ft, including portions of 
  highway 36.

* WHEN...From 4 PM Tuesday to 4 AM PST Wednesday.

* IMPACTS...Travel could be very difficult. Strong winds could cause 
  extensive damage to trees and power lines.

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 you are calling from can be obtained by calling 5 1 1.

&&

$$

For hazard areas see https://www.wrh.noaa.gov/map/?wfo=eka

JJW
11 follow-up statements
837 
WWUS46 KEKA 190354
WSWEKA

URGENT - WINTER WEATHER MESSAGE
National Weather Service Eureka CA
754 PM PST Mon Nov 18 2024

CAZ107-191500-
/O.CON.KEKA.WS.W.0010.241120T0000Z-241121T0500Z/
Northern Trinity-
Including Weaverville, Hwy 299-Oregon Mountain, Trinity Center,
Hwy 299-Buckhorn Summit, and Hwy 3-Scott Mountain
754 PM PST Mon Nov 18 2024

...WINTER STORM WARNING REMAINS IN EFFECT FROM 4 PM TUESDAY TO 9 PM 
PST WEDNESDAY ELEVATIONS ABOVE 2,000 FEET...

* WHAT...Heavy snow possible. Total snow accumulations between 5 and 
  10 inches possible above 2,000 feet, 1 to 3 feet possible above 
  4,000 feet. Winds could gust as high as 50 mph. Lowest snow levels 
  expected during Wednesday morning.

* WHERE...Northeastern Trinity.

* WHEN...From 4 PM Tuesday to 9 PM PST Wednesday.

* IMPACTS...Travel could be very difficult to impossible. Tire 
  chains may be necessary if travelling through mountain passes. 
  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 you are calling from can be obtained by calling 5 1 1.

&&

$$

CAZ108-191500-
/O.CON.KEKA.WS.W.0010.241120T0000Z-241120T1200Z/
Southern Trinity-
754 PM PST Mon Nov 18 2024

...WINTER STORM WARNING REMAINS IN EFFECT FROM 4 PM TUESDAY TO 4 AM 
PST WEDNESDAY...

* WHAT...Heavy snow possible. Total snow accumulations of 5 to 8 
  inches possible. Winds could gust as high as 50 mph.

* WHERE...Portions of southern Trinity to the east of Forest Glen 
  and Hyampom and above around 3500 ft, including portions of 
  highway 36.

* WHEN...From 4 PM Tuesday to 4 AM PST Wednesday.

* IMPACTS...Travel could be very difficult. Strong winds could cause 
  extensive damage to trees and power lines.

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 you are calling from can be obtained by calling 5 1 1.

&&

$$

For hazard areas see https://www.wrh.noaa.gov/map/?wfo=eka

ZVS
248 
WWUS46 KEKA 191216
WSWEKA

URGENT - WINTER WEATHER MESSAGE
National Weather Service Eureka CA
416 AM PST Tue Nov 19 2024

CAZ107-192030-
/O.EXT.KEKA.WS.W.0010.241120T0000Z-241121T0600Z/
Northern Trinity-
Including Weaverville, Hwy 299-Buckhorn Summit, Hwy 3-Scott
Mountain, Hwy 299-Oregon Mountain, and Trinity Center
416 AM PST Tue Nov 19 2024

...WINTER STORM WARNING NOW IN EFFECT FROM 4 PM THIS AFTERNOON TO 10 
PM PST WEDNESDAY ELEVATIONS ABOVE 2,000 FEET...

* WHAT...Heavy snow possible. Total snow accumulations between 5 and 
  12 inches possible above 2,000 feet, 1 to 3 feet possible above 
  3,000 feet. Winds could gust as high as 50 mph. Lowest snow levels 
  expected during Wednesday morning.

* WHERE...Northeastern Trinity.

* WHEN...From 4 PM this afternoon to 10 PM PST Wednesday.

* IMPACTS...Travel could be very difficult to impossible. Tire 
  chains may be necessary if travelling through mountain passes. 
  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 you are calling from can be obtained by calling 5 1 1.

Persons should delay all travel if possible. If travel is absolutely 
necessary, drive with extreme caution and be prepared for sudden 
changes in visibility. Leave plenty of room between you and the 
motorist ahead of you, and allow extra time to reach your 
destination. Avoid sudden braking or acceleration, and be especially 
cautious on hills or when making turns. Make sure your car is 
winterized and in good working order.

&&

$$

CAZ108-192030-
/O.CON.KEKA.WS.W.0010.241120T0000Z-241120T1200Z/
Southern Trinity-
416 AM PST Tue Nov 19 2024

...WINTER STORM WARNING REMAINS IN EFFECT FROM 4 PM THIS AFTERNOON 
TO 4 AM PST WEDNESDAY...

* WHAT...Heavy snow possible. Total snow accumulations of 5 to 8 
  inches possible. Winds could gust as high as 50 mph.

* WHERE...Portions of southern Trinity to the east of Forest Glen 
  and Hyampom and above around 3500 ft, including portions of 
  highway 36.

* WHEN...From 4 PM this afternoon to 4 AM PST Wednesday.

* IMPACTS...Travel could be very difficult. Strong winds could cause 
  extensive damage to trees and power lines.

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 you are calling from can be obtained by calling 5 1 1.

&&

$$

For hazard areas see https://www.wrh.noaa.gov/map/?wfo=eka

TDJ
363 
WWUS46 KEKA 192019
WSWEKA

URGENT - WINTER WEATHER MESSAGE
National Weather Service Eureka CA
1219 PM PST Tue Nov 19 2024

CAZ107-200545-
/O.CON.KEKA.WS.W.0010.241120T0000Z-241121T0600Z/
Northern Trinity-
Including Hwy 299-Buckhorn Summit, Weaverville, Hwy 299-Oregon
Mountain, Hwy 3-Scott Mountain, and Trinity Center
1219 PM PST Tue Nov 19 2024

...WINTER STORM WARNING REMAINS IN EFFECT FROM 4 PM THIS AFTERNOON 
TO 10 PM PST WEDNESDAY ELEVATIONS ABOVE 2,000 FEET...

* WHAT...Heavy snow expected. Total snow accumulations between 5 and 
  12 inches possible above 2,000 feet, 1 to 3 feet possible above 
  3,000 feet. Winds could gust as high as 50 mph. Lowest snow levels 
  expected during Wednesday morning.

* WHERE...Northeastern Trinity.

* WHEN...From 4 PM this afternoon to 10 PM PST Wednesday.

* IMPACTS...Travel could be very difficult to impossible. Tire 
  chains may be necessary if travelling through mountain passes. 
  Strong winds could cause extensive damage to trees and power lines.

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 you are calling from can be obtained by calling 5 1 1.

Persons should delay all travel if possible. If travel is absolutely 
necessary, drive with extreme caution and be prepared for sudden 
changes in visibility. Leave plenty of room between you and the 
motorist ahead of you, and allow extra time to reach your 
destination. Avoid sudden braking or acceleration, and be especially 
cautious on hills or when making turns. Make sure your car is 
winterized and in good working order.

&&

$$

CAZ108-200545-
/O.CON.KEKA.WS.W.0010.241120T0000Z-241120T1200Z/
Southern Trinity-
1219 PM PST Tue Nov 19 2024

...WINTER STORM WARNING REMAINS IN EFFECT FROM 4 PM THIS AFTERNOON 
TO 4 AM PST WEDNESDAY...

* WHAT...Heavy snow expected. Total snow accumulations of 5 to 8 
  inches possible. Winds could gust as high as 50 mph.

* WHERE...Portions of southern Trinity to the east of Forest Glen 
  and Hyampom and above around 3500 ft, including portions of 
  highway 36.

* WHEN...From 4 PM this afternoon to 4 AM PST Wednesday.

* IMPACTS...Travel could be very difficult. Strong winds could cause 
  extensive damage to trees and power lines.

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 you are calling from can be obtained by calling 5 1 1.

&&

$$

For hazard areas see https://www.wrh.noaa.gov/map/?wfo=eka

DB
860 
WWUS46 KEKA 200544
WSWEKA

URGENT - WINTER WEATHER MESSAGE
National Weather Service Eureka CA
944 PM PST Tue Nov 19 2024

CAZ107-201345-
/O.CON.KEKA.WS.W.0010.000000T0000Z-241121T0600Z/
Northern Trinity-
Including Hwy 299-Oregon Mountain, Weaverville, Hwy 299-Buckhorn
Summit, Hwy 3-Scott Mountain, and Trinity Center
944 PM PST Tue Nov 19 2024

...WINTER STORM WARNING REMAINS IN EFFECT UNTIL 10 PM PST WEDNESDAY 
ELEVATIONS ABOVE 2,000 FEET...

* WHAT...Heavy snow expected. Total snow accumulations between 5 and 
  12 inches possible above 2,000 feet, 1 to 3 feet possible above 
  3,000 feet. Winds could gust as high as 50 mph. Lowest snow levels 
  expected during Wednesday morning.

* WHERE...Northeastern Trinity.

* WHEN...Until 10 PM PST Wednesday.

* IMPACTS...Travel could be very difficult to impossible. Tire 
  chains may be necessary if travelling through mountain passes. 
  Gusty winds could bring down tree branches.

* ADDITIONAL DETAILS...This includes highway 299 at Oregon Mountain 
  and Buckhorn Summit as well as highway 3 in multiple areas north 
  of Weaverville.

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 you are calling from can be obtained by calling 5 1 1.

Persons should delay all travel if possible. If travel is absolutely 
necessary, drive with extreme caution and be prepared for sudden 
changes in visibility. Leave plenty of room between you and the 
motorist ahead of you, and allow extra time to reach your 
destination. Avoid sudden braking or acceleration, and be especially 
cautious on hills or when making turns. Make sure your car is 
winterized and in good working order.

&&

$$

CAZ108-201200-
/O.CON.KEKA.WS.W.0010.000000T0000Z-241120T1200Z/
Southern Trinity-
944 PM PST Tue Nov 19 2024

...WINTER STORM WARNING REMAINS IN EFFECT UNTIL 4 AM PST WEDNESDAY...

* WHAT...Heavy snow expected. Total snow accumulations of 5 to 8 
  inches possible. Winds could gust as high as 50 mph.

* WHERE...Portions of southern Trinity to the east of Forest Glen 
  and Hyampom and above around 3500 ft, including portions of 
  highway 36.

* WHEN...Until 4 AM PST Wednesday.

* IMPACTS...Travel could be very difficult. Strong winds could cause 
  extensive damage to trees and power lines.

* ADDITIONAL DETAILS...This includes highway 36 at South Fork 
  Mountain and additional locations above 3000 feet east of South 
  Fork Mountain.

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 you are calling from can be obtained by calling 5 1 1.

&&

$$

For hazard areas see https://www.wrh.noaa.gov/map/?wfo=eka

MKK
907 
WWUS46 KEKA 201141
WSWEKA

URGENT - WINTER WEATHER MESSAGE
National Weather Service Eureka CA
341 AM PST Wed Nov 20 2024

CAZ108-201400-
/O.EXT.KEKA.WS.W.0010.000000T0000Z-241120T1400Z/
Southern Trinity-
341 AM PST Wed Nov 20 2024

...WINTER STORM WARNING NOW IN EFFECT UNTIL 6 AM PST EARLY THIS 
MORNING...

* WHAT...Heavy wet snow. Additional snow accumulations up to one 
  inch. Winds gusting as high as 40 mph.

* WHERE...Portions of southern Trinity to the east of Forest Glen 
  and Hyampom and above around 3500 ft, including portions of 
  highway 36.

* WHEN...Until 6 AM PST early this morning.

* IMPACTS...Roads, and especially bridges and overpasses, will 
  likely become slick and hazardous. Plan on slippery road 
  conditions.

* ADDITIONAL DETAILS...This includes highway 36 at South Fork 
  Mountain and additional locations above 3000 feet east of South 
  Fork Mountain.

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 you are calling from can be obtained by calling 5 1 1.

&&

$$

CAZ107-201945-
/O.CON.KEKA.WS.W.0010.000000T0000Z-241121T0600Z/
Northern Trinity-
Including Trinity Center, Hwy 299-Oregon Mountain, Hwy 3-Scott
Mountain, Hwy 299-Buckhorn Summit, and Weaverville
341 AM PST Wed Nov 20 2024

...WINTER STORM WARNING REMAINS IN EFFECT UNTIL 10 PM PST THIS 
EVENING ELEVATIONS ABOVE 2,000 FEET...

* WHAT...Heavy snow expected. Total snow accumulations between 5 and 
  10 inches possible above 2,000 feet early this morning, 1 to 3 
  feet possible above 3,000 feet. Lowest snow levels expected during 
  Wednesday morning, then snow levels expected to slowly rise 
  through the day today.

* WHERE...Northeastern Trinity.

* WHEN...Until 10 PM PST this evening.

* IMPACTS...Travel could be very difficult to impossible. Tire 
  chains may be necessary if travelling through mountain passes.

* ADDITIONAL DETAILS...This includes highway 299 at Oregon Mountain 
  and Buckhorn Summit as well as highway 3 in multiple areas north 
  of Weaverville.

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 you are calling from can be obtained by calling 5 1 1.

Persons should delay all travel if possible. If travel is absolutely 
necessary, drive with extreme caution and be prepared for sudden 
changes in visibility. Leave plenty of room between you and the 
motorist ahead of you, and allow extra time to reach your 
destination. Avoid sudden braking or acceleration, and be especially 
cautious on hills or when making turns. Make sure your car is 
winterized and in good working order.

&&

$$

For hazard areas see https://www.wrh.noaa.gov/map/?wfo=eka

TDJ
615 
WWUS46 KEKA 201345
WSWEKA

URGENT - WINTER WEATHER MESSAGE
National Weather Service Eureka CA
545 AM PST Wed Nov 20 2024

CAZ108-201600-
/O.EXT.KEKA.WS.W.0010.000000T0000Z-241120T1600Z/
Southern Trinity-
545 AM PST Wed Nov 20 2024

...WINTER STORM WARNING NOW IN EFFECT UNTIL 8 AM PST THIS MORNING...

* WHAT...Heavy snow expected. An additional 2 to 4 inches possible.

* WHERE...Southern Trinity.

* WHEN...Until 8 AM PST this morning.

* IMPACTS...Roads, and especially bridges and overpasses, will 
  likely become slick and hazardous.

* ADDITIONAL DETAILS...This includes highway 36 at South Fork 
  Mountain and additional locations above 3000 feet east of South 
  Fork Mountain.

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 you are calling from can be obtained by calling 5 1 1.

&&

$$

CAZ107-202145-
/O.CON.KEKA.WS.W.0010.000000T0000Z-241121T0600Z/
Northern Trinity-
Including Trinity Center, Hwy 299-Oregon Mountain, Hwy 3-Scott
Mountain, Hwy 299-Buckhorn Summit, and Weaverville
545 AM PST Wed Nov 20 2024

...WINTER STORM WARNING REMAINS IN EFFECT UNTIL 10 PM PST THIS 
EVENING ELEVATIONS ABOVE 2,000 FEET...

* WHAT...Heavy snow expected. Total snow accumulations between 5 and 
  10 inches possible above 2,000 feet early this morning, 1 to 3 
  feet possible above 3,000 feet. Lowest snow levels expected during 
  Wednesday morning, then snow levels expected to slowly rise 
  through the day today.

* WHERE...Northeastern Trinity.

* WHEN...Until 10 PM PST this evening.

* IMPACTS...Travel could be very difficult to impossible. Tire 
  chains may be necessary if travelling through mountain passes.

* ADDITIONAL DETAILS...This includes highway 299 at Oregon Mountain 
  and Buckhorn Summit as well as highway 3 in multiple areas north 
  of Weaverville.

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 you are calling from can be obtained by calling 5 1 1.

Persons should delay all travel if possible. If travel is absolutely 
necessary, drive with extreme caution and be prepared for sudden 
changes in visibility. Leave plenty of room between you and the 
motorist ahead of you, and allow extra time to reach your 
destination. Avoid sudden braking or acceleration, and be especially 
cautious on hills or when making turns. Make sure your car is 
winterized and in good working order.

&&

$$

For hazard areas see https://www.wrh.noaa.gov/map/?wfo=eka
979 
WWUS46 KEKA 202012
WSWEKA

URGENT - WINTER WEATHER MESSAGE
National Weather Service Eureka CA
1212 PM PST Wed Nov 20 2024

CAZ107-210515-
/O.EXT.KEKA.WS.W.0010.000000T0000Z-241121T1100Z/
Northern Trinity-
Including Trinity Center, Hwy 299-Oregon Mountain, Hwy
299-Buckhorn Summit, Hwy 3-Scott Mountain, and Weaverville
1212 PM PST Wed Nov 20 2024

...WINTER STORM WARNING NOW IN EFFECT UNTIL 3 AM PST THURSDAY 
ELEVATIONS ABOVE 2,500 FEET...

* WHAT...Heavy snow expected. Additional accumulations of 12 to 18 
  inches above 3500 feet, 4 to 6 inches between 2500 to 3500 feet 
  and less than an inch below 2500 feet. Snow levels rising through 
  this evening and overnight.

* WHERE...Northeastern Trinity.

* WHEN...Until 3 AM PST Thursday.

* IMPACTS...Roads, and especially bridges and overpasses, will 
  likely become slick and hazardous. The strong winds and weight of 
  snow on tree limbs may down power lines and could cause sporadic 
  power outages. Travel could be very difficult to impossible. Tire 
  chains may be necessary if travelling through mountain passes.

* ADDITIONAL DETAILS...This includes highway 299 at Oregon Mountain 
  and Buckhorn Summit as well as highway 3 in multiple areas north 
  of Weaverville.

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 you are calling from can be obtained by calling 5 1 1.

Persons should delay all travel if possible. If travel is absolutely 
necessary, drive with extreme caution and be prepared for sudden 
changes in visibility. Leave plenty of room between you and the 
motorist ahead of you, and allow extra time to reach your 
destination. Avoid sudden braking or acceleration, and be especially 
cautious on hills or when making turns. Make sure your car is 
winterized and in good working order.

&&

$$

For hazard areas see https://www.wrh.noaa.gov/map/?wfo=eka

DB
343 
WWUS46 KEKA 210517
WSWEKA

URGENT - WINTER WEATHER MESSAGE
National Weather Service Eureka CA
917 PM PST Wed Nov 20 2024

CAZ107-211100-
/O.CON.KEKA.WS.W.0010.000000T0000Z-241121T1100Z/
Northern Trinity-
Including Weaverville, Hwy 299-Oregon Mountain, Hwy 299-Buckhorn
Summit, Hwy 3-Scott Mountain, and Trinity Center
917 PM PST Wed Nov 20 2024

...WINTER STORM WARNING REMAINS IN EFFECT UNTIL 3 AM PST THURSDAY 
ELEVATIONS ABOVE 3,000 FEET...

* WHAT...Heavy snow expected. Additional accumulations of 12 to 18 
  inches above 3500 feet, 4 to 6 inches between 2500 to 3500 feet 
  and less than an inch below 2500 feet. Snow levels rising through 
  this evening and overnight.

* WHERE...Northeastern Trinity.

* WHEN...Until 3 AM PST Thursday.

* IMPACTS...Roads, and especially bridges and overpasses, will 
  likely become slick and hazardous. The strong winds and weight of 
  snow on tree limbs may down power lines and could cause sporadic 
  power outages. Travel could be very difficult. Tire chains may be 
  necessary if travelling through mountain passes.

* ADDITIONAL DETAILS...This includes highway 3 in multiple areas 
  north of Weaverville.

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 you are calling from can be obtained by calling 5 1 1.

Persons should delay all travel if possible. If travel is absolutely 
necessary, drive with extreme caution and be prepared for sudden 
changes in visibility. Leave plenty of room between you and the 
motorist ahead of you, and allow extra time to reach your 
destination. Avoid sudden braking or acceleration, and be especially 
cautious on hills or when making turns. Make sure your car is 
winterized and in good working order.

&&

$$

For hazard areas see https://www.wrh.noaa.gov/map/?wfo=eka

MKK
114 
WWUS46 KEKA 211040
WSWEKA

URGENT - WINTER WEATHER MESSAGE
National Weather Service Eureka CA
240 AM PST Thu Nov 21 2024

CAZ107-211845-
/O.EXT.KEKA.WS.W.0010.000000T0000Z-241122T0600Z/
Northern Trinity-
Including Hwy 3-Scott Mountain
240 AM PST Thu Nov 21 2024

...WINTER STORM WARNING NOW IN EFFECT UNTIL 10 PM PST THIS EVENING 
ELEVATIONS ABOVE 3,500 FEET ...

* WHAT...Heavy snow expected above 3, 500 feet. Additional snow 
  accumulations between 1 and 2 feet.

* WHERE...Northeastern Trinity.

* WHEN...Until 10 PM PST this evening.

* IMPACTS...Roads, and especially bridges and overpasses, will 
  likely become slick and hazardous. The strong winds and weight of 
  snow on tree limbs may down power lines and could cause sporadic 
  power outages. Travel could be very difficult to impossible. Tire 
  chains may be necessary if travelling through mountain passes.

* ADDITIONAL DETAILS...This includes highway 3 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 you are calling from can be obtained by calling 5 1 1.

Persons should delay all travel if possible. If travel is absolutely 
necessary, drive with extreme caution and be prepared for sudden 
changes in visibility. Leave plenty of room between you and the 
motorist ahead of you, and allow extra time to reach your 
destination. Avoid sudden braking or acceleration, and be especially 
cautious on hills or when making turns. Make sure your car is 
winterized and in good working order.

&&

$$

For hazard areas see https://www.wrh.noaa.gov/map/?wfo=eka

ZVS
509 
WWUS46 KEKA 211833
WSWEKA

URGENT - WINTER WEATHER MESSAGE
National Weather Service Eureka CA
1033 AM PST Thu Nov 21 2024

CAZ107-220600-
/O.CON.KEKA.WS.W.0010.000000T0000Z-241122T0600Z/
Northern Trinity-
Including Hwy 3-Scott Mountain
1033 AM PST Thu Nov 21 2024

...WINTER STORM WARNING REMAINS IN EFFECT UNTIL 10 PM PST THIS 
EVENING FOR ELEVATIONS ABOVE 3,500 FEET...

* WHAT...Heavy snow expected above 3,500 feet. Additional snow 
  accumulations between 1 and 2 feet.

* WHERE...Northeastern Trinity.

* WHEN...Until 10 PM PST this evening.

* IMPACTS...Roads, and especially bridges and overpasses, will 
  likely become slick and hazardous. The strong winds and weight of 
  snow on tree limbs may down power lines and could cause sporadic 
  power outages. Travel could be very difficult.

* ADDITIONAL DETAILS...This includes highway 3 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 you are calling from can be obtained by calling 5 1 1.

Persons should delay all travel if possible. If travel is absolutely 
necessary, drive with extreme caution and be prepared for sudden 
changes in visibility. Leave plenty of room between you and the 
motorist ahead of you, and allow extra time to reach your 
destination. Avoid sudden braking or acceleration, and be especially 
cautious on hills or when making turns. Make sure your car is 
winterized and in good working order.

&&

$$

For hazard areas see https://www.wrh.noaa.gov/map/?wfo=eka

DB
381 
WWUS46 KEKA 220536
WSWEKA

URGENT - WINTER WEATHER MESSAGE
National Weather Service Eureka CA
936 PM PST Thu Nov 21 2024

CAZ107-220645-
/O.EXP.KEKA.WS.W.0010.000000T0000Z-241122T0600Z/
Northern Trinity-
Including Hwy 3-Scott Mountain
936 PM PST Thu Nov 21 2024

...WINTER STORM WARNING WILL EXPIRE AT 10 PM PST THIS EVENING...

The threat has ended.

$$

For hazard areas see https://www.wrh.noaa.gov/map/?wfo=eka

MKK

What forecasters said that day

The local office's own words before this winter storm 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 winter storm warning went out at Nov 18, 6:19 AM PST, 5 hours 51 minutes earlier.

Area forecast discussion, Nov 18, 6:19 AM PST, 5 hours 51 minutes before
AREA FORECAST DISCUSSION
National Weather Service Eureka CA
619 AM PST Mon Nov 18 2024

.SYNOPSIS...Scattered showers continue to move onshore along the
coast today. Strong winds develop Tuesday afternoon and evening as
the next storm approaches. Steady, moderate rain is forecast
Wednesday into next weekend. Heavy snow is possible in NE Trinity
Wednesday.

&&

.DISCUSSION...Latest IR satellite imagery depicts a large swath
of cool cloud tops and convective showers over the NEPAC early
this morning behind yesterday's cold front. These are forecast to
continue to move onshore today, bringing scattered showers through
the day primarily north of Cape Mendocino. Local observations
show s now levels currently around 2500 ft, and these are and
these are forecast to slowly rise to 3k to 3.5k ft by this
evening. Shower activity should weaken late tonight as warm air
advection in advance of the next storm begins.

A significantly more potent storm system is forecast to impact the
region tomorrow through this weekend. Ensemble guidance continues to
hold steady on the general pattern, with all clusters depicting an
atmospheric river developing offshore Tuesday and parking itself
over NWRN CA Tuesday night through late in the week, possibly into
the weekend. This will bring a prolonged period of moderate rainfall
with an initial threat of small stream and urban flooding
Wednesday and Thursday, and potentially main stem river concerns
later in the week. A flood watch has been issued for most of the
area in response, see the Hydrology section for more details.

The initial front is forecast to bring a tight pressure gradient to
the coastal counties with very strong southerly winds Tuesday
evening. Sustained winds of 35 to 45 mph with gusts of 60 to 70 mph
are expected on exposed ridges, coastal headlands, and portions of
the coastal plain in Humboldt and Del Norte counties. A High Wind
Warning has been issued for these areas, as downed trees, power
outages, and difficult travel conditions are likely. The strongest
winds are expected just ahead of the frontal passage, as incoming
rain mixes down stronger winds present just above the surface...this
is currently forecast to occur late Tuesday night. Winds then weaken
but remain southerly around 10 to 20 kts behind the front on
Wednesday.

Meanwhile, a few deterministic models (GFS, NAM, ECMWF) continue to
depict cold air getting trapped in Trinity county on Tuesday night
and Wednesday morning as this system approaches, which may allow for
heavy snow in the northeastern portions of Trinity county before
warmer air can move in. This looks most likely east of the Alps and
around Trinity Lake, as well as over Buckhorn Summit and Oregon Mtn,
however may reach as far south as Highway 36. Some uncertainty
remains on just how low snow levels will get. Most guidance agrees
they'll reach at least 3000 ft in NE Trinity Wednesday morning, and
a small but significant portion of the guidance indicates heavy snow
down to Weaverville at this time. Thus have expanded the watch to
include areas above 2000 ft. Some guidance also indicates this
colder air at the surface may linger through Wednesday into Thursday
around Trinity Lake and in the Horn...which means heavy snow could
continue for over 24 hrs on portions of Highway 3 north of
Weaverville. Should this occur, one to multiple feet of snow are
possible Wednesday and Thursday on portions of Highway 3 and 299.
This could significantly impact travel Wednesday. Confidence is
lower on snow levels for areas to the south and east, but there's
about a 50% chance over over 6 inches of snow falling on portions
of Highway 36 east of Forest Glen, so have expanded the Winter
Storm Watch to include these areas. /TDJ

&&

.AVIATION...Post-frontal showers are still being observed across the
region as a cold upper trough cycles over the PNW. Brief periods of
moderate rainfall, reduced visbility's and gusty winds are possible
with these isolated showers, although risk of thunder will diminish
through the morning. Light westerly flow will quickly shift
southerly this afternoon and steadily increase this evening and
overnight ahead of a strong frontal boundary. Mostly VFR conditions
will prevail as ceilings drop into MVFR territory by early Tuesday
morning, beginning in CEC and ACV. Increasing SW flow aloft will
pose a risk for LLWS at the coastal terminals at the end of the TAF
period.

&&

.MARINE...A large NW swell 15 to 16 feet at 13 to 14 seconds will
continue to fill into the waters this morning as winds diminish.
Seas will remain elevated through Tuesday as winds turn southerly
and increase ahead an approaching front. A strong storm system is
expected to arrive late Tuesday afternoon, producing strong winds,
steep seas and heavy rainfall. The Storm Watches have been upgraded
to warnings in all zones for high confidence in 45 to 65 knot gusts
developing late Tuesday night along the frontal boundary.
Significant wave heights will be further elevated to 22 to 27 feet
at 12 to 13 seconds early Wednesday morning in response to these
winds. Northern zones will likely see the larger end of these wave
heights corresponding to the strongest winds offshore, while the
southern waters will experience slightly reduced 18 to 22 foot wave
heights. An additional near-shore swell will maintain 12 to 14 foot
seas through late week even as the most severe winds diminish.

&&

.HYDROLOGY...A moderate to strong atmospheric river is forecast
to move over NWRN CA late Tuesday and persist through the rest of
the week. NAEFS mean IVT is showing a prolonged period of
anomalously high values (500 to 800 kg/ms) from the SW,
perpendicular to the local terrain. This will likely lead to a
prolonged period of persistent rainfall this week, further
enhanced by the local orography. Latest QPF guidance is showing 4
to 8 inches of precip falling Wednesday and Thursday across the
CWA from Tuesday night through Thursday night, with rain likely
continuing into the weekend.

Latest MRMS soil moisture modeling is indicating 50% to 70%
saturated soils at the moment in Humboldt and Del Norte, with 20% to
30% in Mendocino and Lake Counties. Thus the initial bands of precip
late Tuesday night and Wednesday likely will be absorbed, however
with the prolonged nature of this incoming system, saturation is
likely, leading to enhanced runoff. This may initially lead to small
streams and creeks flooding, as well as flooding in urban areas.
Main stem rivers are forecast to respond late this week to the
persistent rainfall as well, however just how high they will reach
remains uncertain.

&&

.EKA WATCHES/WARNINGS/ADVISORIES...
CA...
     High Wind Warning from 4 PM Tuesday to 2 AM PST Wednesday
     for CAZ101-102.

     Flood Watch from late Tuesday night through late Thursday
     night for CAZ101>106-108>115.

     High Wind Warning from 7 PM Tuesday to 4 AM PST Wednesday
     for CAZ103-105-106.

     High Wind Warning from 4 PM Tuesday to 6 AM PST Wednesday
     for CAZ104.

     Winter Storm Watch from Tuesday afternoon through Wednesday
     evening for CAZ107.

     Winter Storm Watch from Tuesday afternoon through late
     Tuesday night for CAZ108.

NORTHWEST CALIFORNIA COASTAL WATERS...
     Small Craft Advisory until 3 PM PST Tuesday for PZZ450-455-
     475.

     Storm Warning from 3 PM Tuesday to 3 AM PST Wednesday for
     PZZ450-455-475.

     Small Craft Advisory until 9 AM PST Tuesday for PZZ470.

     Storm Warning from 9 AM Tuesday to 3 AM PST Wednesday for
     PZZ470.

&&

Visit us at https://www.weather.gov/eureka

Follow us on Facebook and Twitter at:
https://www.facebook.com/NWSEureka
https://www.twitter.com/NWSEureka

For forecast zone information
see the forecast zone map online:
https://www.weather.gov/images/eka/zonemap.png

In the hours before

Special weather statement, Nov 18, 9:09 AM PST, 3 hours 1 minute before
Special Weather Statement
National Weather Service Eureka CA
909 AM PST Mon Nov 18 2024

CAZ102-103-105-181745-
Northern Humboldt Coast CA-Del Norte Interior CA-
Northern Humboldt Interior CA-
909 AM PST Mon Nov 18 2024

...A STRONG THUNDERSTORM WILL IMPACT NORTH CENTRAL HUMBOLDT AND SOUTH
CENTRAL DEL NORTE COUNTIES THROUGH 945 AM PST...

At 907 AM PST, Doppler radar was tracking a strong thunderstorm 10
miles northwest of Trinidad, or 13 miles southwest of Orick, moving
east at 25 mph.

HAZARD...Pea size hail.

SOURCE...Radar indicated.

IMPACT...Minor damage to outdoor objects is possible.

Locations impacted include...
Orick, Hoopa, Willow Creek, Trinidad, Westhaven-Moonstone, Weitchpec,
McKinleyville, Arcata Arpt, and Fieldbrook.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

&&

LAT...LON 4115 12414 4123 12411 4142 12407 4145 12361
      4142 12365 4140 12364 4138 12366 4138 12359
      4089 12370 4097 12412 4103 12411 4105 12413
      4105 12415 4114 12416
TIME...MOT...LOC 1707Z 289DEG 20KT 4117 12429

MAX HAIL SIZE...0.25 IN
MAX WIND GUST...<30 MPH

/EYS

The office that day

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

IssuedProductOfficeCountiesLasted
Nov 18, 4:21 AM PSTFlood WatchEKADel Norte, Humboldt, Lake, Mendocino, Trinity5 days
Nov 18, 4:52 AM PSTHigh Wind WarningEKADel Norte, Humboldt49 hr
Nov 18, 8:39 AM PSTStorm WarningEKA46 hr
Nov 18, 9:09 AM PSTSpecial Weather StatementEKAHumboldt36 min
Nov 18, 9:34 AM PSTSpecial Marine WarningEKA26 min
Nov 18, 12:33 PM PSTSpecial Weather StatementEKAHumboldt27 min
Nov 18, 12:39 PM PSTSpecial Weather StatementEKAHumboldt36 min

Nearby

Winter Storm Warnings in California, 2024Every winter storm warning in 2024

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.