Alert archive / Montana / Winter Storm Warnings in 2021
Winter Storm Warning 13, NWS Missoula, MT
NWS Missoula, MT issued this winter storm warning at Dec 20, 2021, 7:33 AM MST for Missoula County, Ravalli County, Montana. It was in force for 3 hr. 6 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
- Dec 20, 2021, 7:33 AM MST (14:33 UTC)
- Expired
- Dec 20, 2021, 11:00 AM MST
- In force
- 3 hr
- Issued by
- NWS Missoula, MT
Counties Missoula County, MT, Ravalli County, MT
The radar
The Missoula radar (KMSX), 54 km from the middle of the area, began a volume at 14:33 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
| Time | Report | Where | Remark |
|---|---|---|---|
| Dec 20, 7:43 AM MST | HEAVY SNOW 6 | Lolo, MT | |
| Dec 20, 7:44 AM MST | HEAVY SNOW 6 | Conner, MT | |
| Dec 20, 7:50 AM MST | SNOW 4 | 1 Sse Stevensville, MT | |
| Dec 20, 8:30 AM MST | SNOW 3 | 4 Nnw Ninemile, MT | |
| Dec 20, 10:27 AM MST | HEAVY SNOW 10 | 1 Se Pinesdale, MT | |
| Dec 20, 11:00 AM MST | SNOW 4 | 6 Nw Missoula, MT |
Local storm reports filed while the alert was in force, from inside its polygon or its counties.
The nearest sounding before it
Spokane, WA (KOTX), launched 12:00Z, 2.6 hours before the alert went out and 220 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
- 1069 m above ground
- 0-6 km bulk shear
- 73 kt
- 0-1 km storm-relative helicity
- 82 m²/s²
- 0-3 km storm-relative helicity
- 274 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
644 WWUS45 KMSO 201433 WSWMSO URGENT - WINTER WEATHER MESSAGE National Weather Service Missoula MT 733 AM MST Mon Dec 20 2021 MTZ005-210000- /O.UPG.KMSO.WW.Y.0072.000000T0000Z-211221T0000Z/ /O.NEW.KMSO.WS.W.0013.211220T1433Z-211220T1800Z/ /O.NEW.KMSO.WW.Y.0073.211220T1800Z-211221T0000Z/ Missoula/Bitterroot Valleys- 733 AM MST Mon Dec 20 2021 ...WINTER STORM WARNING IN EFFECT UNTIL 11 AM MST THIS MORNING... ...WINTER WEATHER ADVISORY IN EFFECT FROM 11 AM THIS MORNING TO 5 PM MST THIS AFTERNOON... * WHAT...For the Winter Storm Warning, heavy snow. Additional snow accumulations of up to 2 inches. Hazardous driving conditions are present in the Missoula Valley this morning due to heavy snowfall and very slick roads. For the Winter Weather Advisory, snow expected. Total snow accumulations of up to one inch. * WHERE...Missoula/Bitterroot Valleys. * WHEN...For the Winter Storm Warning, until 11 AM MST this morning. For the Winter Weather Advisory, from 11 AM this morning to 5 PM MST this afternoon. * IMPACTS...Travel could be affected. PRECAUTIONARY/PREPAREDNESS ACTIONS... If you must travel, keep an extra flashlight, food, and water in your vehicle in case of an emergency. Slow down and use caution while traveling. The latest road conditions for the state you are calling from can be obtained by calling 5 1 1. && $$ IDZ005-210000- /O.CON.KMSO.WW.Y.0072.000000T0000Z-211221T0000Z/ Northern Clearwater Mountains- 633 AM PST Mon Dec 20 2021 ...WINTER WEATHER ADVISORY REMAINS IN EFFECT UNTIL 4 PM PST THIS AFTERNOON... * WHAT...Snow. Additional snow accumulations of 2 to 6 inches. * WHERE...Elk River, Highway 11 Pierce to Headquarters, and Pierce. * WHEN...Until 4 PM PST Monday. * IMPACTS...Travel could be difficult. PRECAUTIONARY/PREPAREDNESS ACTIONS... Slow down and use caution while traveling. The latest road conditions for the state you are calling from can be obtained by calling 5 1 1. && $$ IDZ006-210000- /O.CON.KMSO.WW.Y.0072.000000T0000Z-211221T0000Z/ Southern Clearwater Mountains- 633 AM PST Mon Dec 20 2021 ...WINTER WEATHER ADVISORY REMAINS IN EFFECT UNTIL 4 PM PST THIS AFTERNOON... * WHAT...Snow. Additional snow accumulations of 1 to 3 inches below 3500 feet. 3 to 7 inches snow above 3500 feet. * WHERE...Dixie, Elk City, and Highway 12 Lowell to Lolo Pass. * WHEN...Until 4 PM PST Monday. * IMPACTS...Travel could be difficult. PRECAUTIONARY/PREPAREDNESS ACTIONS... Slow down and use caution while traveling. The latest road conditions for the state you are calling from can be obtained by calling 5 1 1. && $$ MTZ006-210000- /O.CON.KMSO.WW.Y.0072.000000T0000Z-211221T0000Z/ Bitterroot/Sapphire Mountains- 733 AM MST Mon Dec 20 2021 ...WINTER WEATHER ADVISORY REMAINS IN EFFECT UNTIL 5 PM MST THIS AFTERNOON... * WHAT...Snow. Additional snow accumulations of 3 to 6 inches. * WHERE...Bitterroot/Sapphire Mountains. * WHEN...Until 5 PM MST Monday. * IMPACTS...Travel could be difficult. PRECAUTIONARY/PREPAREDNESS ACTIONS... Slow down and use caution while traveling. The latest road conditions for the state you are calling from can be obtained by calling 5 1 1. && $$ MTZ004-210000- /O.CON.KMSO.WW.Y.0072.000000T0000Z-211221T0000Z/ Lower Clark Fork Region- 733 AM MST Mon Dec 20 2021 ...WINTER WEATHER ADVISORY REMAINS IN EFFECT UNTIL 5 PM MST THIS AFTERNOON... * WHAT...Snow. Additional snow accumulations of 3 to 5 inches from Lookout Pass to mile marker 10 on I-90. Up to 2 inches elsewhere. * WHERE...Evaro Hill, Highway 200 Thompson Falls to Plains, Highway 200 Trout Creek to Heron, and I-90 Lookout Pass to Haugan. * WHEN...Until 5 PM MST Monday. * IMPACTS...Travel could be difficult. PRECAUTIONARY/PREPAREDNESS ACTIONS... Slow down and use caution while traveling. The latest road conditions for the state you are calling from can be obtained by calling 5 1 1. && $$ MTZ007-043-210000- /O.CON.KMSO.WW.Y.0072.000000T0000Z-211221T0000Z/ Butte/Blackfoot Region-Potomac/Seeley Lake Region- 733 AM MST Mon Dec 20 2021 ...WINTER WEATHER ADVISORY REMAINS IN EFFECT UNTIL 5 PM MST THIS AFTERNOON... * WHAT...Additional snow accumulations of up to three inches and icy conditions as temperatures dropped below freezing overnight after the snow has started accumulating. * WHERE...Butte, Georgetown Lake, Highway 12 Garrison to Elliston, Homestake Pass, and MacDonald Pass. * WHEN...For the Winter Storm Warning, until 5 AM MST early this morning. For the Winter Weather Advisory, until 5 PM MST this afternoon. * IMPACTS...Travel could be difficult. PRECAUTIONARY/PREPAREDNESS ACTIONS... Slow down and use caution while traveling. The latest road conditions for the state you are calling from can be obtained by calling 5 1 1. && $$ MTZ003-210000- /O.CON.KMSO.WW.Y.0072.000000T0000Z-211221T0000Z/ Flathead/Mission Valleys- 733 AM MST Mon Dec 20 2021 ...WINTER WEATHER ADVISORY REMAINS IN EFFECT UNTIL 5 PM MST THIS AFTERNOON... * WHAT...Snow. Additional snow accumulations of 2 to 4 inches. Areas around Flathead Lake and the Mission Valley will be on the higher end of the snow amount range. The Flathead Valley will see around 2 inches through the day. * WHERE...Flathead Lake, Flathead Valley, Mission Valley, and Polson. * WHEN...Until 5 PM MST Monday. * IMPACTS...Travel could be difficult. PRECAUTIONARY/PREPAREDNESS ACTIONS... Slow down and use caution while traveling. The latest road conditions for the state you are calling from can be obtained by calling 5 1 1. && $$
1 follow-up statement
676 WWUS45 KMSO 201734 WSWMSO URGENT - WINTER WEATHER MESSAGE National Weather Service Missoula MT 1034 AM MST Mon Dec 20 2021 MTZ005-210000- /O.EXP.KMSO.WS.W.0013.000000T0000Z-211220T1800Z/ /O.CON.KMSO.WW.Y.0073.211220T1800Z-211221T0000Z/ Missoula/Bitterroot Valleys- 1034 AM MST Mon Dec 20 2021 ...WINTER WEATHER ADVISORY REMAINS IN EFFECT UNTIL 5 PM MST THIS AFTERNOON... ...WINTER STORM WARNING WILL EXPIRE AT 11 AM MST THIS MORNING... * WHAT...Snow expected. Light to moderate snow will continue through the rest of the day. An additional 1 to 2 inches of snow are expected, with isolated high amounts. * WHERE...Missoula/Bitterroot Valleys. * WHEN...For the Winter Storm Warning, until 11 AM MST this morning. For the Winter Weather Advisory, from 11 AM this morning to 5 PM MST this afternoon. * IMPACTS...Travel could be affected. PRECAUTIONARY/PREPAREDNESS ACTIONS... Slow down and use caution while traveling. The latest road conditions for the state you are calling from can be obtained by calling 5 1 1. && $$ IDZ005-210000- /O.CON.KMSO.WW.Y.0072.000000T0000Z-211221T0000Z/ Northern Clearwater Mountains- 934 AM PST Mon Dec 20 2021 ...WINTER WEATHER ADVISORY REMAINS IN EFFECT UNTIL 4 PM PST THIS AFTERNOON... * WHAT...Snow. Additional snow accumulations of 2 to 6 inches. * WHERE...Elk River, Highway 11 Pierce to Headquarters, and Pierce. * WHEN...Until 4 PM PST Monday. * IMPACTS...Travel could be difficult. PRECAUTIONARY/PREPAREDNESS ACTIONS... Slow down and use caution while traveling. The latest road conditions for the state you are calling from can be obtained by calling 5 1 1. && $$ IDZ006-210000- /O.CON.KMSO.WW.Y.0072.000000T0000Z-211221T0000Z/ Southern Clearwater Mountains- 934 AM PST Mon Dec 20 2021 ...WINTER WEATHER ADVISORY REMAINS IN EFFECT UNTIL 4 PM PST THIS AFTERNOON... * WHAT...Snow. Additional snow accumulations of 1 to 3 inches below 3500 feet. 3 to 7 inches snow above 3500 feet. * WHERE...Dixie, Elk City, and Highway 12 Lowell to Lolo Pass. * WHEN...Until 4 PM PST Monday. * IMPACTS...Travel could be difficult. PRECAUTIONARY/PREPAREDNESS ACTIONS... Slow down and use caution while traveling. The latest road conditions for the state you are calling from can be obtained by calling 5 1 1. && $$ MTZ006-210000- /O.CON.KMSO.WW.Y.0072.000000T0000Z-211221T0000Z/ Bitterroot/Sapphire Mountains- 1034 AM MST Mon Dec 20 2021 ...WINTER WEATHER ADVISORY REMAINS IN EFFECT UNTIL 5 PM MST THIS AFTERNOON... * WHAT...Snow. Additional snow accumulations of 3 to 6 inches. * WHERE...Bitterroot/Sapphire Mountains. * WHEN...Until 5 PM MST Monday. * IMPACTS...Travel could be difficult. PRECAUTIONARY/PREPAREDNESS ACTIONS... Slow down and use caution while traveling. The latest road conditions for the state you are calling from can be obtained by calling 5 1 1. && $$ MTZ004-210000- /O.CON.KMSO.WW.Y.0072.000000T0000Z-211221T0000Z/ Lower Clark Fork Region- 1034 AM MST Mon Dec 20 2021 ...WINTER WEATHER ADVISORY REMAINS IN EFFECT UNTIL 5 PM MST THIS AFTERNOON... * WHAT...Snow. Additional snow accumulations of 3 to 5 inches from Lookout Pass to mile marker 10 on I-90. Up to 2 inches elsewhere. * WHERE...Evaro Hill, Highway 200 Thompson Falls to Plains, Highway 200 Trout Creek to Heron, and I-90 Lookout Pass to Haugan. * WHEN...Until 5 PM MST Monday. * IMPACTS...Travel could be difficult. PRECAUTIONARY/PREPAREDNESS ACTIONS... Slow down and use caution while traveling. The latest road conditions for the state you are calling from can be obtained by calling 5 1 1. && $$ MTZ007-043-210000- /O.CON.KMSO.WW.Y.0072.000000T0000Z-211221T0000Z/ Butte/Blackfoot Region-Potomac/Seeley Lake Region- 1034 AM MST Mon Dec 20 2021 ...WINTER WEATHER ADVISORY REMAINS IN EFFECT UNTIL 5 PM MST THIS AFTERNOON... * WHAT...Additional snow accumulations of up to three inches and icy conditions as temperatures dropped below freezing overnight after the snow has started accumulating. * WHERE...Butte, Georgetown Lake, Highway 12 Garrison to Elliston, Homestake Pass, and MacDonald Pass. * WHEN...For the Winter Storm Warning, until 5 AM MST early this morning. For the Winter Weather Advisory, until 5 PM MST this afternoon. * IMPACTS...Travel could be difficult. PRECAUTIONARY/PREPAREDNESS ACTIONS... Slow down and use caution while traveling. The latest road conditions for the state you are calling from can be obtained by calling 5 1 1. && $$ MTZ003-210000- /O.CON.KMSO.WW.Y.0072.000000T0000Z-211221T0000Z/ Flathead/Mission Valleys- 1034 AM MST Mon Dec 20 2021 ...WINTER WEATHER ADVISORY REMAINS IN EFFECT UNTIL 5 PM MST THIS AFTERNOON... * WHAT...Snow. Additional snow accumulations of 2 to 4 inches. Areas around Flathead Lake and the Mission Valley will be on the higher end of the snow amount range. The Flathead Valley will see around 2 inches through the day. * WHERE...Flathead Lake, Flathead Valley, Mission Valley, and Polson. * WHEN...Until 5 PM MST Monday. * IMPACTS...Travel could be difficult. PRECAUTIONARY/PREPAREDNESS ACTIONS... Slow down and use caution while traveling. The latest road conditions for the state you are calling from can be obtained by calling 5 1 1. && $$
The office that day
Everything else NWS Missoula, MT issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Dec 20, 7:33 AM MST | Winter Weather Advisory | MSO | Missoula, Ravalli | 18 hr |
Nearby
Winter Storm Warnings in Montana, 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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.