Alert archive / Montana / Winter Weather Advisories in 2021

Winter Weather Advisory 33, NWS Missoula, MT

April 9, 2021Flathead County, Lake County, Montana

NWS Missoula, MT issued this winter weather advisory at Apr 9, 2021, 4:44 PM MDT for Flathead County, Lake County, Montana. It took effect at Apr 10, 2021, 5:00 AM MDT. It was in force for 7 hr.

The area

The counties it named.

The facts

Issued
Apr 9, 2021, 4:44 PM MDT (22:44 UTC)
In effect from
Apr 10, 2021, 5:00 AM MDT
Expired
Apr 10, 2021, 12:00 PM MDT
In force
7 hr
Issued by
NWS Missoula, MT

Counties Flathead County, MT, Lake County, MT

The radar

The Missoula radar (KMSX), 104 km from the middle of the area, began a volume at 22:50 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, 10.7 hours before the alert went out and 177 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-pSkew-T log-p diagram, Spokane, WA at 12:00Z on 2021-04-09Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Spokane, WA at 12:00Z on 2021-04-09The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 192 square meters per square second.19395878Sfc1 km3 km6 km9 kmRMLM
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
1774 m above ground
0-6 km bulk shear
46 kt
0-1 km storm-relative helicity
192 m²/s²
0-3 km storm-relative helicity
233 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 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 Apr 9, 2:51 PM MDT, 1 hour 53 minutes earlier.

Area forecast discussion, Apr 9, 2:51 PM MDT, 1 hour 53 minutes before
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The office that day

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

IssuedProductOfficeCountiesLasted
Apr 9, 11:53 AM MDTLake Wind AdvisoryMSOFlathead, Lake, Sanders27 hr
Apr 9, 11:53 AM MDTWind AdvisoryMSODeer Lodge, Granite, Lake, Missoula, Powell, Ravalli and 1 more36 hr

Nearby

Winter Weather Advisories in Montana, 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.