Alert archive / Montana / Snow Squall Warnings in 2023

Snow Squall Warning 3, NWS Missoula, MT

March 2, 2023Missoula County, Ravalli County, Montana

NWS Missoula, MT issued this snow squall warning at Mar 2, 2023, 8:12 PM MST for Missoula County, Ravalli County, Montana. It was in force for 48 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: Mar 2, 2023, 8:12 PM MST (03:12 UTC)
Expired: Mar 2, 2023, 9:00 PM MST
In force: 48 min
Issued by: NWS Missoula, MT
Area: Storm-based polygon

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 03:12 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 00:00Z, 3.2 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.

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: 1430 m above ground
0-6 km bulk shear: 78 kt
0-1 km storm-relative helicity: 149 m²/s²
0-3 km storm-relative helicity: 66 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 Mar 2, 5:06 PM MST, 3 hours 6 minutes earlier.

Area forecast discussion, Mar 2, 5:06 PM MST, 3 hours 6 minutes before

Area Forecast Discussion National Weather Service Missoula MT 214 PM
MST Thu Mar 2 2023

.DISCUSSION...Snow showers are present across the region with
winds from the southwest in and along a cold frontal passage. The
showers will briefly lower visibilities as they pass. Winds will to
gust 35 to 40 mph in higher elevations while many valleys will
receive gusts 15 to 25 mph. Temperatures will cool below freezing
for all elevations after sunset, setting the stage for valleys to
see minor snowfall accumulations onto roadways. Valley accumulations
will be favored across southern portions of the Seeley-Swan Valley,
and Mission Valleys, and areas south and east of Missoula.

On Friday, west winds and convective snow showers will continue and
surface winds will trend weaker than Thursday. Snow showers will
produce localized areas of heavy snow, leading to brief periods of
slick and highly changeable driving conditions, even with higher sun
angles of early March.

Saturday will begin with a brief break in the active weather. By the
afternoon, a cold front from east of the Continental Divide will
begin to affect northwest Montana, primarily along US Highway 2 near
Marias Pass. There is moderate confidence for this front to move
across the Flathead Valley and Southwest Montana. Lower confidence
exists for the front to reach into the rest of western Montana.

The longwave trough over much of the western U.S. will persist
through much of next week. The unstable cold air mass will bring
snow showers across the entire Northern Rockies each day.
Temperatures will be 10 to 20 degrees colder than normal through
much of next week. This translates to high temps in the 30s and lows
in the teens.

&&

.AVIATION...A cold front will move through the Northern Rockies
tonight and Friday. Increased instability and cold air will result
in vicinity snow showers with gusty outflow winds 25-35 mph at all
terminals through 03/2300z.

&&

.MSO WATCHES/WARNINGS/ADVISORIES...
MT...     Winter Weather Advisory until 8 PM MST Friday for West
Glacier      Region.

     Winter Weather Advisory until 8 PM MST Friday for Lower Clark
     Fork Region.

ID...Winter Weather Advisory until 7 PM PST Friday for Northern
     Clearwater Mountains...Southern Clearwater Mountains.

&&

In the hours before

Special weather statement, Mar 2, 6:55 PM MST, 1 hour 17 minutes before

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Special weather statement, Mar 2, 7:02 PM MST, 1 hour 10 minutes before

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Special weather statement, Mar 2, 7:14 PM MST, 58 minutes before

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Special weather statement, Mar 2, 7:26 PM MST, 46 minutes before

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Special weather statement, Mar 2, 7:46 PM MST, 26 minutes before

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Special weather statement, Mar 2, 7:57 PM MST, 15 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
Mar 2, 5:46 PM MST	Special Weather Statement	MSO	Sanders	44 min
Mar 2, 5:49 PM MST	Special Weather Statement	MSO	Mineral	26 min
Mar 2, 6:28 PM MST	Snow Squall Warning	MSO	Flathead	47 min
Mar 2, 6:31 PM MST	Snow Squall Warning	MSO	Flathead, Lincoln, Sanders	29 min
Mar 2, 6:55 PM MST	Special Weather Statement	MSO	Lincoln	35 min
Mar 2, 7:02 PM MST	Special Weather Statement	MSO	Missoula	43 min
Mar 2, 7:14 PM MST	Special Weather Statement	MSO	Lake	46 min
Mar 2, 7:26 PM MST	Special Weather Statement	MSO	Missoula	49 min
Mar 2, 7:46 PM MST	Special Weather Statement	MSO		44 min
Mar 2, 7:57 PM MST	Special Weather Statement	MSO	Missoula	48 min
Mar 2, 8:40 PM MST	Special Weather Statement	MSO	Mineral	35 min
Mar 2, 8:42 PM MST	Special Weather Statement	MSO	Lake	33 min
Mar 2, 9:08 PM MST	Special Weather Statement	MSO	Powell	52 min
Mar 2, 9:33 PM MST	Special Weather Statement	MSO	Missoula	42 min
Mar 2, 10:17 PM MST	Special Weather Statement	MSO	Powell	58 min

Nearby

Snow Squall Warnings in Montana, 2023 Every snow squall warning in 2023

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.