Alert archive / Minnesota / Mesoscale Discussions in 2021

Mesoscale Discussion 1980

December 10, 20218 counties in Iowa; 26 counties in Minnesota; 8 counties in Wisconsin

The Storm Prediction Center issued this mesoscale discussion at Dec 10, 2021, 3:31 PM CST for 8 counties in Iowa; 26 counties in Minnesota; 8 counties in Wisconsin. It was in force for 4 hr.

The area

The outline as issued.

The facts

Issued
Dec 10, 2021, 3:31 PM CST (21:31 UTC)
Expired
Dec 10, 2021, 7:30 PM CST
In force
4 hr
Issued by
the Storm Prediction Center
Concerning
Heavy snow
All 42 counties

Clay County, IA, Dickinson County, IA, Emmet County, IA, Kossuth County, IA, Lyon County, IA, Osceola County, IA, Winnebago County, IA, Worth County, IA, Blue Earth County, MN, Brown County, MN, Cottonwood County, MN, Dakota County, MN, Dodge County, MN, Faribault County, MN, Fillmore County, MN, Freeborn County, MN, Goodhue County, MN, Houston County, MN, Jackson County, MN, Le Sueur County, MN, Martin County, MN, Mower County, MN, Murray County, MN, Nicollet County, MN, Nobles County, MN, Olmsted County, MN, Rice County, MN, Scott County, MN, Sibley County, MN, Steele County, MN, Wabasha County, MN, Waseca County, MN, Watonwan County, MN, Winona County, MN, Buffalo County, WI, Dunn County, WI, Eau Claire County, WI, Jackson County, WI, La Crosse County, WI, Pepin County, WI, Pierce County, WI, Trempealeau County, WI

The radar

The Minneapolis radar (KMPX), 88 km from the middle of the area, began a volume at 21:32 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

Minneapolis, MN (KMPX), launched 12:00Z, 9.5 hours before the alert went out and 88 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, Minneapolis, MN at 12:00Z on 2021-12-10Temperature 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, Minneapolis, MN at 12:00Z on 2021-12-10The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -94 square meters per square second.1939587897117136Sfc1 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
1610 m above ground
0-6 km bulk shear
62 kt
0-1 km storm-relative helicity
-94 m²/s²
0-3 km storm-relative helicity
17 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

847 
ACUS11 KWNS 102132
SWOMCD
SPC MCD 102131 
WIZ000-MNZ000-IAZ000-110130-

Mesoscale Discussion 1980
NWS Storm Prediction Center Norman OK
0331 PM CST Fri Dec 10 2021

Areas affected...Far Northern IA....West-Central WI...Southern MN

Concerning...Heavy snow 

Valid 102131Z - 110130Z

SUMMARY...A band of heavy snowfall, with rates around 1" to 2" per
hour, is expected to develop from far northern IA across southern MN
into west-central WI.

DISCUSSION...Recent regional radar imagery and surface observations
continue to show predominantly moderate snowfall from far southwest
MN into far northwest IA. This radar imagery also depicts the
western branch of the warm conveyor well, shown by the band of
precipitation from southern MN southeastward through northern IL.
Expectation is for the ongoing snowfall band to further
consolidate/organize during the next few hours, with the persistent
warm-air advection contributing to an increase in snowfall rates.
Lift across this region will be augmented by large-scale ascent,
resulting in robust lift throughout the dendritic growth zone. A
band of heavy snowfall is anticipated as result, with rates around
1-2" per hour likely into the evening.

..Mosier.. 12/10/2021

...Please see www.spc.noaa.gov for graphic product...

ATTN...WFO...ARX...MPX...DMX...FSD...

LAT...LON   44099585 44699398 45019178 44599043 43699100 43049534
            43429648 44099585

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Dec 10, 12:27 PM CSTMesoscale DiscussionSPCClay, Dickinson, Emmet, Lyon, O'Brien, Osceola and 1 more4 hr

Nearby

Mesoscale Discussions in Minnesota, 2021Mesoscale Discussions in Iowa, 2021Mesoscale Discussions in Wisconsin, 2021Every mesoscale discussion 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.