Alert archive / Montana / Winter Weather Advisories in 2021
Winter Weather Advisory 40, NWS Missoula, MT
NWS Missoula, MT issued this winter weather advisory at May 22, 2021, 2:13 PM MDT for 8 counties in Montana; Lemhi County, Idaho. It took effect at May 23, 2021, 4:00 AM MDT. It was in force for 8 hr.
The area
The counties it named.
The facts
- Issued
- May 22, 2021, 2:13 PM MDT (20:13 UTC)
- In effect from
- May 23, 2021, 4:00 AM MDT
- Expired
- May 23, 2021, 12:00 PM MDT
- In force
- 8 hr
- Issued by
- NWS Missoula, MT
Counties Lemhi County, ID, Deer Lodge County, MT, Flathead County, MT, Granite County, MT, Lake County, MT, Missoula County, MT, Powell County, MT, Ravalli County, MT, Silver Bow County, MT
The radar
The Missoula radar (KMSX), 60 km from the middle of the area, began a volume at 20:13 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, 8.2 hours before the alert went out and 247 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
- 1833 m above ground
- 0-6 km bulk shear
- 21 kt
- 0-1 km storm-relative helicity
- 49 m²/s²
- 0-3 km storm-relative helicity
- 113 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 May 22, 3:02 AM MDT, 11 hours 11 minutes earlier.
Area forecast discussion, May 22, 3:02 AM MDT, 11 hours 11 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 |
|---|---|---|---|---|
| May 21, 8:31 PM MDT | Winter Weather Advisory | MSO | Deer Lodge, Granite, Powell, Silver Bow | 3 hr |
| May 22, 3:28 PM MDT | Special Weather Statement | MSO | Clearwater | 47 min |
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.