Alert archive / Montana / Winter Storm Warnings in 2021
Winter Storm Warning 7, NWS Missoula, MT
NWS Missoula, MT issued this winter storm warning at Feb 21, 2021, 10:39 AM MST for Flathead County, Lake County, Montana. It took effect at Feb 21, 2021, 3:00 PM MST. It was in force for 5 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
- Feb 21, 2021, 10:39 AM MST (17:39 UTC)
- In effect from
- Feb 21, 2021, 3:00 PM MST
- Expired
- Feb 21, 2021, 7:30 PM MST
- In force
- 5 hr
- Issued by
- NWS Missoula, MT
Counties Flathead County, MT, Lake County, MT
The radar
The Missoula radar (KMSX), 104 km from the middle of the area, began a volume at 17:36 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
Spokane, WA (KOTX), launched 12:00Z, 5.7 hours before the alert went out and 177 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
- 717 m above ground
- 0-6 km bulk shear
- 54 kt
- 0-1 km storm-relative helicity
- 196 m²/s²
- 0-3 km storm-relative helicity
- 272 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
251 WWUS45 KMSO 211739 WSWMSO URGENT - WINTER WEATHER MESSAGE National Weather Service Missoula MT 1039 AM MST Sun Feb 21 2021 MTZ002-221745- /O.NEW.KMSO.WS.W.0007.210221T2200Z-210222T1800Z/ West Glacier Region- 1039 AM MST Sun Feb 21 2021 ...WINTER STORM WARNING IN EFFECT FROM 3 PM THIS AFTERNOON TO 11 AM MST MONDAY... * WHAT...Heavy snow and blowing snow expected. Total snow accumulations of 4 to 7 inches. Winds gusting as high as 50 mph. * WHERE...Marias Pass. * WHEN...From 3 PM this afternoon to 11 AM MST Monday. * IMPACTS...Travel could be affected. Widespread blowing snow could significantly reduce visibility. Strong winds could cause tree damage. 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. && $$ MTZ004-006-221745- /O.CON.KMSO.WW.Y.0022.000000T0000Z-210223T0600Z/ Lower Clark Fork Region-Bitterroot/Sapphire Mountains- 1039 AM MST Sun Feb 21 2021 ...WINTER WEATHER ADVISORY REMAINS IN EFFECT UNTIL 11 PM MST MONDAY... * WHAT...Snow. Additional snow accumulations of 2 to 13 inches. Winds gusting as high as 50 mph. * WHERE...I-90 Lookout Pass to Haugan, Highway 93 Sula to Lost Trail Pass, and Lolo Pass. * WHEN...Until 11 PM MST Monday. * IMPACTS...Travel could be very difficult. Patchy blowing snow could significantly reduce visibility. Gusty winds could bring down tree branches. PRECAUTIONARY/PREPAREDNESS ACTIONS... Slow down and use caution while traveling. The latest road conditions for the state you are calling from can be obtained by calling 5 1 1. && $$
3 follow-up statements
003 WWUS45 KMSO 211755 CCA WSWMSO URGENT - WINTER WEATHER MESSAGE...CORRECTED National Weather Service Missoula MT 1055 AM MST Sun Feb 21 2021 MTZ002-221745- /O.COR.KMSO.WS.W.0007.210221T2200Z-210222T1800Z/ West Glacier Region- 1055 AM MST Sun Feb 21 2021 ...WINTER STORM WARNING IN EFFECT FROM 3 PM THIS AFTERNOON TO 11 AM MST MONDAY... * WHAT...Heavy snow and blowing snow expected. Total snow accumulations of 3 to 7 inches at Marias Pass, up to 2 inches elsewhere. Winds gusting as high as 50 mph. * WHERE...Marias Pass, West Glacier, Bad Rock Canyon, Essex, Highway 83 Bigfork to Swan Lake. and Polebridge. * WHEN...From 3 PM this afternoon to 11 AM MST Monday. * IMPACTS...Travel could be affected. Widespread blowing snow could significantly reduce visibility especially over Marias Pass. Strong winds could cause tree damage. 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. && $$ MTZ004-006-221745- /O.CON.KMSO.WW.Y.0022.000000T0000Z-210223T0600Z/ Lower Clark Fork Region-Bitterroot/Sapphire Mountains- 1055 AM MST Sun Feb 21 2021 ...WINTER WEATHER ADVISORY REMAINS IN EFFECT UNTIL 11 PM MST MONDAY... * WHAT...Snow. Additional snow accumulations of 2 to 13 inches. Winds gusting as high as 50 mph. * WHERE...I-90 Lookout Pass to Haugan, Highway 93 Sula to Lost Trail Pass, and Lolo Pass. * WHEN...Until 11 PM MST Monday. * IMPACTS...Travel could be very difficult. Patchy blowing snow could significantly reduce visibility. Gusty winds could bring down tree branches. PRECAUTIONARY/PREPAREDNESS ACTIONS... Slow down and use caution while traveling. The latest road conditions for the state you are calling from can be obtained by calling 5 1 1. && $$
901 WWUS45 KMSO 212324 WSWMSO URGENT - WINTER WEATHER MESSAGE National Weather Service Missoula MT 424 PM MST Sun Feb 21 2021 MTZ002-221800- /O.CON.KMSO.WS.W.0007.000000T0000Z-210222T1800Z/ West Glacier Region- 424 PM MST Sun Feb 21 2021 ...WINTER STORM WARNING REMAINS IN EFFECT UNTIL 11 AM MST MONDAY... * WHAT...Heavy snow and blowing snow expected. Total snow accumulations of 5 to 10 inches between Essex and Marias Pass. Total snow accumulations of 1 to 3 inches at lower elevations. Winds gusting as high as 55 mph. * WHERE...Essex, Swan Lake, Marias Pass, and Polebridge. * WHEN...Until 11 AM MST Monday. * IMPACTS...Travel could be very difficult to impossible. Widespread blowing snow could significantly reduce visibility. Strong winds could cause tree damage. 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. && $$ IDZ005-006-222330- /O.EXA.KMSO.WW.Y.0022.000000T0000Z-210223T0600Z/ Northern Clearwater Mountains-Southern Clearwater Mountains- 324 PM PST Sun Feb 21 2021 ...WINTER WEATHER ADVISORY IN EFFECT UNTIL 10 PM PST MONDAY ABOVE 4000 FEET... * WHAT...Snow above 4000 feet. Total snow accumulations 6 to 12 inches between 4,000 and 4,500 feet, with 1 to 2 feet expected above 4,500 feet. Winds gusting as high as 45 mph. * WHERE...Northern Clearwater Mountains and Southern Clearwater Mountains. * WHEN...Until 10 PM PST Monday. * IMPACTS...Travel could be affected. The combination of heavy snow and strong winds will create dangerous backcountry travel conditions. PRECAUTIONARY/PREPAREDNESS ACTIONS... Slow down and use caution while traveling. The latest road conditions for the state you are calling from can be obtained by calling 5 1 1. && $$ MTZ006-222330- /O.CON.KMSO.WW.Y.0022.000000T0000Z-210223T0600Z/ Bitterroot/Sapphire Mountains- 424 PM MST Sun Feb 21 2021 ...WINTER WEATHER ADVISORY REMAINS IN EFFECT UNTIL 11 PM MST MONDAY... * WHAT...Snow. Total snow accumulations of 4 to 8 inches for Lost Trail Pass and the Sapphire Mountains, with 1 to 2 feet expected above 4,500 feet in the Bitterroot Mountains. Winds gusting as high as 50 mph. * WHERE...Bitterroot/Sapphire Mountains. * WHEN...Until 11 PM MST Monday. * IMPACTS...Travel could be affected. The combination of heavy snow and strong winds will create dangerous backcountry travel conditions, particularly in the Bitterroot Mountains. 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. && $$ MTZ004-222330- /O.CON.KMSO.WW.Y.0022.000000T0000Z-210223T0600Z/ Lower Clark Fork Region- 424 PM MST Sun Feb 21 2021 ...WINTER WEATHER ADVISORY REMAINS IN EFFECT UNTIL 11 PM MST MONDAY ABOVE 4000 FEET... * WHAT...Snow above 4000 feet. Total snow accumulations of 7 to 12 inches for Lookout Pass. Winds gusting as high as 45 mph. * WHERE...Lower Clark Fork Region. * WHEN...Until 11 PM MST Monday. * IMPACTS...Travel could be affected. Patchy areas of blowing snow could significantly reduce visibility. Gusty winds could bring down tree branches. PRECAUTIONARY/PREPAREDNESS ACTIONS... Slow down and use caution while traveling. The latest road conditions for the state you are calling from can be obtained by calling 5 1 1. && $$
079 WWUS45 KMSO 220230 WSWMSO URGENT - WINTER WEATHER MESSAGE National Weather Service Missoula MT 730 PM MST Sun Feb 21 2021 MTZ002-230230- /O.CAN.KMSO.WS.W.0007.000000T0000Z-210222T1800Z/ /O.NEW.KMSO.WS.W.0008.210222T1200Z-210223T1200Z/ West Glacier Region- 730 PM MST Sun Feb 21 2021 ...WINTER STORM WARNING IN EFFECT FROM 5 AM MONDAY TO 5 AM MST TUESDAY... * WHAT...Heavy snow and blowing snow expected. Total snow accumulations of 5 to 10 inches between Essex and Marias Pass. Total snow accumulations of 1 to 3 inches at lower elevations. Winds gusting as high as 55 mph. * WHERE...Essex, Swan Lake, Marias Pass, and Polebridge. * WHEN...From 5 AM Monday to 5 AM MST Tuesday. * IMPACTS...Travel could be very difficult to impossible. Widespread blowing snow could significantly reduce visibility. Strong winds could cause tree damage. 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. && $$ MTZ006-230230- /O.CON.KMSO.WW.Y.0022.000000T0000Z-210223T0600Z/ Bitterroot/Sapphire Mountains- 730 PM MST Sun Feb 21 2021 ...WINTER WEATHER ADVISORY REMAINS IN EFFECT UNTIL 11 PM MST MONDAY... * WHAT...Snow. Total snow accumulations of 4 to 8 inches for Lost Trail Pass and the Sapphire Mountains, with 1 to 2 feet expected above 4,500 feet in the Bitterroot Mountains. Winds gusting as high as 50 mph. * WHERE...Bitterroot/Sapphire Mountains. * WHEN...Until 11 PM MST Monday. * IMPACTS...Travel could be affected. The combination of heavy snow and strong winds will create dangerous backcountry travel conditions, particularly in the Bitterroot Mountains. PRECAUTIONARY/PREPAREDNESS ACTIONS... Slow down and use caution while traveling. The latest road conditions for the state you are calling from can be obtained by calling 5 1 1. && $$ IDZ005-006-230230- /O.CON.KMSO.WW.Y.0022.000000T0000Z-210223T0600Z/ Northern Clearwater Mountains-Southern Clearwater Mountains- 630 PM PST Sun Feb 21 2021 ...WINTER WEATHER ADVISORY REMAINS IN EFFECT UNTIL 10 PM PST MONDAY ABOVE 4000 FEET... * WHAT...Snow above 4000 feet. Total snow accumulations 6 to 12 inches between 4,000 and 4,500 feet, with 1 to 2 feet expected above 4,500 feet. Winds gusting as high as 45 mph. * WHERE...Northern Clearwater Mountains and Southern Clearwater Mountains. * WHEN...Until 10 PM PST Monday. * IMPACTS...Travel could be affected. The combination of heavy snow and strong winds will create dangerous backcountry travel conditions. 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. && $$ MTZ004-230230- /O.CON.KMSO.WW.Y.0022.000000T0000Z-210223T0600Z/ Lower Clark Fork Region- 730 PM MST Sun Feb 21 2021 ...WINTER WEATHER ADVISORY REMAINS IN EFFECT UNTIL 11 PM MST MONDAY ABOVE 4000 FEET... * WHAT...Snow above 4000 feet. Total snow accumulations of 7 to 12 inches for Lookout Pass. Winds gusting as high as 45 mph. * WHERE...Lower Clark Fork Region. * WHEN...Until 11 PM MST Monday. * IMPACTS...Travel could be affected. Patchy areas of blowing snow could significantly reduce visibility. Gusty winds could bring down tree branches. PRECAUTIONARY/PREPAREDNESS ACTIONS... Slow down and use caution while traveling. The latest road conditions for the state you are calling from can be obtained by calling 5 1 1. && $$
The office that day
Everything else NWS Missoula, MT issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Feb 21, 8:20 AM MST | Winter Weather Advisory | MSO | Deer Lodge, Flathead, Granite, Lake, Lincoln, Mineral and 5 more | 71 hr |
| Feb 21, 10:42 AM MST | High Wind Warning | MSO | Flathead, Lincoln, Sanders | 24 hr |
| Feb 21, 10:42 AM MST | Wind Advisory | MSO | Flathead, Lake, Sanders | 36 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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.