Alert archive / California / Winter Storm Warnings in 2021
Winter Storm Warning 9, NWS Medford, OR
NWS Medford, OR issued this winter storm warning at Mar 17, 2021, 11:52 AM PDT for Siskiyou County, California. It took effect at Mar 18, 2021, 5:00 AM PDT. It was in force for 8 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
- Mar 17, 2021, 11:52 AM PDT (18:52 UTC)
- In effect from
- Mar 18, 2021, 5:00 AM PDT
- Expired
- Mar 18, 2021, 12:44 PM PDT
- In force
- 8 hr
- Issued by
- NWS Medford, OR
County Siskiyou County, CA
The radar
The Medford radar (KMAX), 56 km from the middle of the area, began a volume at 18:50 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, 6.9 hours before the alert went out and 89 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.
- Mixed-layer CAPE
- 0 J/kg
- Mixed-layer CIN
- No buoyant parcel
- Mixed-layer LCL
- 974 m above ground
- 0-6 km bulk shear
- 28 kt
- 0-1 km storm-relative helicity
- 51 m²/s²
- 0-3 km storm-relative helicity
- 55 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
953 WWUS46 KMFR 171852 WSWMFR URGENT - WINTER WEATHER MESSAGE National Weather Service Medford OR 1152 AM PDT Wed Mar 17 2021 CAZ082-083-181200- /O.UPG.KMFR.WS.A.0006.210318T1200Z-210319T0600Z/ /O.NEW.KMFR.WW.Y.0025.210318T1200Z-210319T0600Z/ /O.NEW.KMFR.WS.W.0009.210318T1200Z-210319T0600Z/ South Central Siskiyou County- North Central and Southeast Siskiyou County- Including the city of Mount Shasta 1152 AM PDT Wed Mar 17 2021 ...WINTER STORM WARNING IN EFFECT FROM 5 AM TO 11 PM PDT THURSDAY ABOVE 4000 FEET... ...WINTER WEATHER ADVISORY IN EFFECT FROM 5 AM TO 11 PM PDT THURSDAY ABOVE 3500 FEET... * WHAT...For the Winter Storm Warning above 4000 feet, heavy wet snow expected. Total snow accumulations 6 to 8 inches. Winds gusting as high as 50 to 60 mph. For the Winter Weather Advisory above 3500 feet, wet snow expected. Total snow accumulations of 2 to 6 inches. Winds gusting as high as 40 mph. * WHERE...For the Winter Storm Warning, portions of Highway 89, including Snowmans Summit, and the Mt Shasta Ski Road. For the Winter Weather Advisory, portions of Interstate 5, including Black Butte Summit and Mt Shasta City. * WHEN...From 5 AM to 11 PM PDT Thursday. * IMPACTS...Travel could be very difficult. The hazardous conditions could impact the morning or evening commute. Strong winds could cause tree damage and possible power outages. * ADDITIONAL DETAILS...Snow levels will start around 3500 ft in the early morning when precipitation first begins. Snow levels are expected to rise some during the day and a rain/snow mix is expected for the Mt Shasta City area during the daylight hours. Snow levels fall again after sunset, but precipitation will become more showery and less intense. * View the hazard area in detail at https://www.wrh.noaa.gov/mfr/HAZARD PRECAUTIONARY/PREPAREDNESS ACTIONS... * Travel is strongly discouraged because of dangerous conditions. * If you must travel, keep tire chains, a flashlight, blankets, food, water, medications, and a fully charged phone with you. * The safest place during a winter storm is indoors. * A Winter Storm Warning means that severe winter weather is likely and poses a threat to life and property. Take protective action now. && $$ CAZ080-181200- /O.NEW.KMFR.WW.Y.0025.210318T1200Z-210319T0600Z/ Western Siskiyou County- 1152 AM PDT Wed Mar 17 2021 ...WINTER WEATHER ADVISORY IN EFFECT FROM 5 AM TO 11 PM PDT THURSDAY ABOVE 4500 FEET... * WHAT...Snow expected above 4500 feet. Total snow accumulations of 4 to 6 inches, with up to 8 inches expected in the highest terrain. Winds gusting as high as 50 to 60 mph. * WHERE...Higher terrain of western Siskiyou County, Sawyers Bar Road, including Etna Summit, and State Rt 3, including Scott Mt Summit. * WHEN...From 5 AM to 11 PM PDT Thursday. * IMPACTS...Travel could be very difficult. The hazardous conditions could impact the morning or evening commute. Gusty winds could bring down tree branches. * View the hazard area in detail at https://www.wrh.noaa.gov/mfr/HAZARD PRECAUTIONARY/PREPAREDNESS ACTIONS... * Slow down and allow extra time to reach your destination. * Carry tire chains and be prepared for snow covered roads and limited visibilities. * See http://quickmap.dot.ca.gov for latest road conditions. * A Winter Weather Advisory for snow means that periods of snow will cause travel difficulties. && $$ Visit us at https://www.weather.gov/Medford
2 follow-up statements
219 WWUS46 KMFR 181200 WSWMFR URGENT - WINTER WEATHER MESSAGE National Weather Service Medford OR 500 AM PDT Thu Mar 18 2021 CAZ082-083-182200- /O.CON.KMFR.WS.W.0009.000000T0000Z-210319T0600Z/ /O.CON.KMFR.WW.Y.0025.000000T0000Z-210319T0600Z/ South Central Siskiyou County- North Central and Southeast Siskiyou County- Including the city of Mount Shasta 500 AM PDT Thu Mar 18 2021 ...WINTER STORM WARNING REMAINS IN EFFECT UNTIL 11 PM PDT THIS EVENING ABOVE 4000 FEET... ...WINTER WEATHER ADVISORY REMAINS IN EFFECT UNTIL 11 PM PDT THIS EVENING ABOVE 3500 FEET... * WHAT...For the Winter Storm Warning above 4000 feet, heavy wet snow expected. Total snow accumulations 6 to 8 inches. Winds gusting as high as 50 to 60 mph. For the Winter Weather Advisory above 3500 feet, wet snow expected. Total snow accumulations of 2 to 6 inches. Winds gusting as high as 40 mph. * WHERE...For the Winter Storm Warning, portions of Highway 89, including Snowmans Summit, and the Mt Shasta Ski Road. For the Winter Weather Advisory, portions of Interstate 5, including Black Butte Summit and Mt Shasta City. * WHEN...Until 11 PM PDT. * IMPACTS...Travel could be very difficult. The hazardous conditions could impact the morning or evening commute. Strong winds could cause tree damage and possible power outages. * ADDITIONAL DETAILS...Snow levels will start around 3500 ft in the early morning when precipitation first begins. Snow levels are expected to rise some during the day and a rain/snow mix is expected for the Mt Shasta City area during the daylight hours. Snow levels fall again after sunset, but precipitation will become more showery and less intense. * View the hazard area in detail at https://www.wrh.noaa.gov/map/?wfo=mfr PRECAUTIONARY/PREPAREDNESS ACTIONS... * Travel is strongly discouraged because of dangerous conditions. * If you must travel, keep tire chains, a flashlight, blankets, food, water, medications, and a fully charged phone with you. * The safest place during a winter storm is indoors. * A Winter Storm Warning means that severe winter weather is likely and poses a threat to life and property. Take protective action now. && $$ CAZ080-182200- /O.CON.KMFR.WW.Y.0025.000000T0000Z-210319T0600Z/ Western Siskiyou County- 500 AM PDT Thu Mar 18 2021 ...WINTER WEATHER ADVISORY REMAINS IN EFFECT UNTIL 11 PM PDT THIS EVENING ABOVE 4500 FEET... * WHAT...Snow expected above 4500 feet. Total snow accumulations of 4 to 6 inches, with up to 8 inches expected in the highest terrain. Winds gusting as high as 50 to 60 mph. * WHERE...Higher terrain of western Siskiyou County, Sawyers Bar Road, including Etna Summit, and State Rt 3, including Scott Mt Summit. * WHEN...Until 11 PM PDT. * IMPACTS...Travel could be very difficult. The hazardous conditions could impact the morning or evening commute. Gusty winds could bring down tree branches. * View the hazard area in detail at https://www.wrh.noaa.gov/map/?wfo=mfr PRECAUTIONARY/PREPAREDNESS ACTIONS... * Slow down and allow extra time to reach your destination. * Carry tire chains and be prepared for snow covered roads and limited visibilities. * See http://quickmap.dot.ca.gov for latest road conditions. * A Winter Weather Advisory for snow means that periods of snow will cause travel difficulties. && $$ Visit us at https://www.weather.gov/Medford
506 WWUS46 KMFR 181944 WSWMFR URGENT - WINTER WEATHER MESSAGE National Weather Service Medford OR 1244 PM PDT Thu Mar 18 2021 CAZ082-083-190600- /O.CAN.KMFR.WS.W.0009.000000T0000Z-210319T0600Z/ /O.CON.KMFR.WW.Y.0025.000000T0000Z-210319T0600Z/ South Central Siskiyou County- North Central and Southeast Siskiyou County- 1244 PM PDT Thu Mar 18 2021 ...WINTER WEATHER ADVISORY REMAINS IN EFFECT UNTIL 11 PM PDT THIS EVENING ABOVE 4000 FEET... ...WINTER STORM WARNING IS CANCELLED... * WHAT...Wet snow above 4000 feet. Additional snow accumulations of 3 to 6 inches. Winds gusting as high as 50 mph. * WHERE...In south central Siskiyou County, portions of Highway 89, including Snowmans Summit, and the Mt Shasta Ski Road. * WHEN...Until 11 PM PDT this evening. * IMPACTS...Plan on slippery road conditions. The hazardous conditions could impact the evening commute. * ADDITIONAL DETAILS...Brief periods of a rain and snow mix down to 3500 ft are possible through this evening. * View the hazard area in detail at https://www.wrh.noaa.gov/map/?wfo=mfr PRECAUTIONARY/PREPAREDNESS ACTIONS... * Slow down and allow extra time to reach your destination. * Carry tire chains and be prepared for snow covered roads and limited visibilities. * See http://quickmap.dot.ca.gov for latest road conditions. * A Winter Weather Advisory for snow means that periods of snow will cause travel difficulties. && $$ CAZ080-190600- /O.CON.KMFR.WW.Y.0025.000000T0000Z-210319T0600Z/ Western Siskiyou County- 1244 PM PDT Thu Mar 18 2021 ...WINTER WEATHER ADVISORY REMAINS IN EFFECT UNTIL 11 PM PDT THIS EVENING ABOVE 4500 FEET... * WHAT...Wet snow above 4500 feet. Additional snow accumulations of 3 to 5 inches. Winds gusting as high as 50 mph. * WHERE...Higher terrain of western Siskiyou County, Sawyers Bar Road, including Etna Summit, and State Rt 3, including Scott Mt Summit. * WHEN...Until 11 PM PDT this evening. * IMPACTS...Travel could be very difficult. The hazardous conditions could impact the evening commute. Gusty winds could bring down tree branches. * View the hazard area in detail at https://www.wrh.noaa.gov/map/?wfo=mfr PRECAUTIONARY/PREPAREDNESS ACTIONS... * Slow down and allow extra time to reach your destination. * Carry tire chains and be prepared for snow covered roads and limited visibilities. * See http://quickmap.dot.ca.gov for latest road conditions. * A Winter Weather Advisory for snow means that periods of snow will cause travel difficulties. && $$ Visit us at https://www.weather.gov/Medford
The office that day
Everything else NWS Medford, OR issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Mar 17, 3:22 AM PDT | Wind Advisory | MFR | Modoc, Siskiyou | 44 hr |
| Mar 17, 3:48 AM PDT | Winter Storm Watch | MFR | Siskiyou | 8 hr |
| Mar 17, 11:52 AM PDT | Winter Weather Advisory | MFR | Siskiyou | 35 hr |
Nearby
Winter Storm Warnings in California, 2021Every winter storm warning in 2021
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.