Alert archive / Montana / Snow Squall Warnings in 2022

Snow Squall Warning 20, NWS Missoula, MT

December 1, 2022Ravalli County, Montana; Lemhi County, Idaho

NWS Missoula, MT issued this snow squall warning at Dec 1, 2022, 10:43 AM MST for Ravalli County, Montana; Lemhi County, Idaho. It was in force for 47 min. 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 1, 2022, 10:43 AM MST (17:43 UTC)
Expired: Dec 1, 2022, 11:30 AM MST
In force: 47 min
Issued by: NWS Missoula, MT
Area: Storm-based polygon

Counties Lemhi County, ID, Ravalli County, MT

The radar

The Missoula radar (KMSX), 170 km from the middle of the area, began a volume at 17:48 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

Great_falls, MT (KTFX), launched 12:00Z, 5.7 hours before the alert went out and 340 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 518 m above ground
0-6 km bulk shear: 90 kt
0-1 km storm-relative helicity: 460 m²/s²
0-3 km storm-relative helicity: 526 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

What forecasters said that day

The local office's own words before this snow squall warning went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Missoula, MT wrote its last area forecast discussion before this snow squall warning went out at Dec 1, 3:09 AM MST, 7 hours 34 minutes earlier.

Area forecast discussion, Dec 1, 3:09 AM MST, 7 hours 34 minutes before

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In the hours before

Local storm report, Dec 1, 9:17 AM MST, 1 hour 26 minutes before

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Local storm report, Dec 1, 9:32 AM MST, 1 hour 11 minutes before

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Local storm report, Dec 1, 9:43 AM MST, 1 hour before

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Local storm report, Dec 1, 10:29 AM MST, 14 minutes before

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Local storm report, Dec 1, 10:40 AM MST, 3 minutes before

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Local storm report, Dec 1, 10:41 AM MST, 2 minutes before

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The office that day

Everything else NWS Missoula, MT issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Dec 1, 4:48 AM MST	Winter Weather Advisory	MSO	Flathead, Lake, Sanders	13 hr
Dec 1, 7:58 AM MST	Special Weather Statement	MSO	Missoula	77 min
Dec 1, 3:55 PM MST	Special Weather Statement	MSO	Deer Lodge, Silver Bow	50 min
Dec 1, 4:12 PM MST	Snow Squall Warning Significant damage threat	MSO	Deer Lodge, Granite, Powell, Silver Bow	48 min
Dec 1, 4:56 PM MST	Snow Squall Warning	MSO	Silver Bow	19 min

Nearby

Snow Squall Warnings in Montana, 2022 Snow Squall Warnings in Idaho, 2022 Every snow squall warning in 2022

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.