Alert archive / Montana / Winter Weather Advisories in 2021
Winter Weather Advisory 75, NWS Missoula, MT
NWS Missoula, MT issued this winter weather advisory at Dec 22, 2021, 1:28 PM MST for 11 counties in Montana; Clearwater County, Idaho County, Idaho. It took effect at Dec 22, 2021, 11:00 PM MST. It was in force for 12 hr.
The area
The counties it named.
The facts
- Issued
- Dec 22, 2021, 1:28 PM MST (20:28 UTC)
- In effect from
- Dec 22, 2021, 11:00 PM MST
- Expired
- Dec 23, 2021, 11:00 AM MST
- In force
- 12 hr
- Issued by
- NWS Missoula, MT
Counties Clearwater County, ID, Idaho County, ID, Deer Lodge County, MT, Flathead County, MT, Granite County, MT, Lake County, MT, Lincoln County, MT, Mineral County, MT, Missoula County, MT, Powell County, MT, Ravalli County, MT, Sanders County, MT, Silver Bow County, MT
The radar
The Missoula radar (KMSX), 22 km from the middle of the area, began a volume at 20:31 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, 8.5 hours before the alert went out and 280 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
- 2132 m above ground
- 0-6 km bulk shear
- 39 kt
- 0-1 km storm-relative helicity
- 72 m²/s²
- 0-3 km storm-relative helicity
- 135 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
What forecasters said that day
The local office's own words before this winter weather advisory 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 winter weather advisory went out at Dec 22, 3:03 AM MST, 10 hours 25 minutes earlier.
Area forecast discussion, Dec 22, 3:03 AM MST, 10 hours 25 minutes before
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</html>The office that day
Everything else NWS Missoula, MT issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Dec 22, 1:35 AM MST | Winter Weather Advisory | MSO | Flathead, Lake, Lincoln, Mineral, Missoula, Sanders | 9 hr |
| Dec 22, 2:09 AM MST | Dense Fog Advisory | MSO | Missoula, Ravalli | 7 hr |
Nearby
Winter Weather Advisories in Montana, 2021Winter Weather Advisories in Idaho, 2021Every winter weather advisory 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.