Alert archive / Montana / Snow Squall Warnings in 2022
Snow Squall Warning 9, NWS Great Falls, MT
NWS Great Falls, MT issued this snow squall warning at Nov 27, 2022, 3:18 PM MST for Jefferson County, Lewis and Clark County, Montana. It was in force for 42 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
- Nov 27, 2022, 3:18 PM MST (22:18 UTC)
- Expired
- Nov 27, 2022, 4:00 PM MST
- In force
- 42 min
- Issued by
- NWS Great Falls, MT
- Area
- Storm-based polygon
- Damage threat
- Significant
The radar
The Great Falls radar (KTFX), 112 km from the middle of the area, began a volume at 22:21 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, 10.3 hours before the alert went out and 155 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
- 1679 m above ground
- 0-6 km bulk shear
- 40 kt
- 0-1 km storm-relative helicity
- 230 m²/s²
- 0-3 km storm-relative helicity
- 270 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
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 Great Falls, MT wrote its last area forecast discussion before this snow squall warning went out at Nov 27, 2:54 PM MST, 24 minutes earlier.
Area forecast discussion, Nov 27, 2:54 PM MST, 24 minutes before
Area Forecast Discussion National Weather Service Great Falls MT 254 PM MST Sun Nov 27 2022 .SYNOPSIS... Areas of snow will progress further through Southwest Montana Sunday evening. Temperatures will turn much colder through the week ahead. A widespread light snow event is likely toward the end of the week. && .DISCUSSION... HRRR forecasts have captured reasonably effectively the observed bands of shallow convective snow that have developed over central Montana, expected to move through Southwest Montana this evening. The bands of snow are supported by weak instability, with CAPE values nearing 100 J/kg. Large dewpoint depressions at the surface indicate wet bulb temperatures in the lower to mid 30s, so evaporative cooling with the onset of precipitation is supporting wet snow to the surface at lower elevations. The surface pressure gradient has begun to weaken as the surface low over Southern Alberta begins to move away to the east. Strong winds continue, with occasional gusts to 45 mph occurring. A few locations did earlier exceed the 58 mph high wind warning criteria, but overall trend in forecasts and observations is below this threshold, so high wind warnings are cancelled. Mid-level lapse rates are steepening with colder temperatures aloft. Thus, periods of snow are likely to continue over mountain areas tonight. Winter Weather Advisories remain in effect for these areas of snow and blowing snow. Snow gradually ends tonight from north to south as surface high pressure builds in with steadily colder temperatures. Portions of Southwest Montana do remain under a left jet exit region, so snow is expected to continue over this area through Monday. Generally fair but cold weather settles in for Tuesday, with scattered light snow flurries possible. NBM 50th percentile Max temperatures are in the upper single digits and lower teens on Tuesday afternoon. Weak warm advection and shortwave ridging aloft provides for a brief rebound in temperatures on Wednesday, though still in the teens and 20s for most areas. Wind chill below -20F may occur Wednesday morning as wind picks up to bring the warmer air into the region. Another strong cold front backs into North-central Montana on Thursday, providing a return to single digit temperatures. The southward extent of this cold front remains uncertain, as it depends on how far south a Pacific shortwave system tracks through the intermountain west. Nonetheless, moisture ascending over the cold air on the southwest flow aloft is expected to generate a period of widespread light to moderate snow Thursday night into Friday. The NBM is suggesting that much of the Golden Triangle region has over a 40% chance of seeing at least 2 inches of snow, which could be enough to cause some minor impacts if realized. && .AVIATION... 1100 AM MST Sun Nov 27 2022 (27/18Z TAF period) Strong winds expand east and south today ahead of an approaching cold front. A brief narrow band of moderate snow may impact central and southwest terminals this afternoon into early evening as the cold front moves across central and southwest terminals this afternoon into early evening, with VFR conditions possibly sharply reducing to low MVFR/IFR or lower. Additional light snow and snow showers will then be possible through the remainder of the TAF period for southwest terminals, though there is considerable uncertainty on the timing. Refer to weather.gov/zlc for more detailed regional aviation weather and hazard information. && .PRELIMINARY POINT TEMPS/POPS... GTF 12 19 1 13 / 30 20 10 0 CTB 7 14 -2 10 / 70 20 10 0 HLN 12 19 1 13 / 70 20 20 0 BZN 8 20 -4 9 / 100 10 30 10 WYS 2 20 -12 12 / 90 60 40 20 DLN 6 18 -4 10 / 90 20 20 0 HVR 12 18 3 12 / 30 10 10 0 LWT 11 19 -2 9 / 50 10 10 0 && .TFX WATCHES/WARNINGS/ADVISORIES... && http://www.weather.gov/greatfalls
In the hours before
Local storm report, Nov 27, 11:35 AM MST, 3 hours 43 minutes before
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</html>Local storm report, Nov 27, 11:36 AM MST, 3 hours 42 minutes before
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</html>Special weather statement, Nov 27, 12:32 PM MST, 2 hours 46 minutes before
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</html>Special weather statement, Nov 27, 2:02 PM MST, 1 hour 16 minutes before
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</html>Local storm report, Nov 27, 2:07 PM MST, 1 hour 11 minutes before
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</html>Local storm report, Nov 27, 2:35 PM MST, 43 minutes before
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</html>The office that day
Everything else NWS Great Falls, MT issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Nov 27, 3:55 PM MST | Snow Squall Warning | TFX | Broadwater, Jefferson, Lewis and Clark | 35 min |
| Nov 27, 4:32 PM MST | Snow Squall Warning | TFX | Broadwater, Jefferson | 43 min |
Nearby
Snow Squall Warnings in Montana, 2022Every 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.