Alert archive / Wisconsin / Mesoscale Discussions in 2021

Mesoscale Discussion 1949

November 21, 2021Dickinson County, Menominee County, Michigan; 21 counties in Wisconsin

The Storm Prediction Center issued this mesoscale discussion at Nov 21, 2021, 1:36 PM CST for Dickinson County, Menominee County, Michigan; 21 counties in Wisconsin. It was in force for 3 hr.

The area

The outline as issued.

The facts

Issued
Nov 21, 2021, 1:36 PM CST (19:36 UTC)
Expired
Nov 21, 2021, 4:30 PM CST
In force
3 hr
Issued by
the Storm Prediction Center
Concerning
Snow squall
All 23 counties

Dickinson County, MI, Menominee County, MI, Adams County, WI, Brown County, WI, Calumet County, WI, Door County, WI, Florence County, WI, Forest County, WI, Kewaunee County, WI, Langlade County, WI, Lincoln County, WI, Marathon County, WI, Marinette County, WI, Menominee County, WI, Oconto County, WI, Oneida County, WI, Outagamie County, WI, Portage County, WI, Shawano County, WI, Waupaca County, WI, Waushara County, WI, Winnebago County, WI, Wood County, WI

The radar

The Green Bay radar (KGRB), 89 km from the middle of the area, began a volume at 19:39 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

Green Bay/Straub, WI (KGRB), launched 12:00Z, 7.6 hours before the alert went out and 91 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, Green Bay/Straub, WI at 12:00Z on 2021-11-21Temperature 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°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Green Bay/Straub, WI at 12:00Z on 2021-11-21The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 151 square meters per square second.1939587897Sfc1 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
1176 m above ground
0-6 km bulk shear
54 kt
0-1 km storm-relative helicity
151 m²/s²
0-3 km storm-relative helicity
191 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

162 
ACUS11 KWNS 211936
SWOMCD
SPC MCD 211936 
MIZ000-WIZ000-212230-

Mesoscale Discussion 1949
NWS Storm Prediction Center Norman OK
0136 PM CST Sun Nov 21 2021

Areas affected...Northeast Wisconsin

Concerning...Snow Squall 

Valid 211936Z - 212230Z

SUMMARY...Scattered snow showers will continue across portions of
northeast Wisconsin this afternoon. Strong winds accompanying these
snow showers may result in visibility dropping to less than a
quarter-mile at times.

DISCUSSION...Atmospheric response to strong frontogenesis in the
850-700 millibar layer is supporting bands of snow showers across
northeast Wisconsin. These snow bands are occurring within a region
of strong winds, gusting to between 35 and 45 mph at times. The
combination of intense snow bands and strong gusty winds will result
in visibility briefly falling to around or below a quarter-mile at
times. The threat should end later this afternoon as frontogenetic
forcing continues to progress through the region.

..Marsh.. 11/21/2021

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

ATTN...WFO...MQT...GRB...MKX...ARX...

LAT...LON   45698980 46108896 46068796 45618690 44388725 43878808
            44019094 45698980

Nearby

Mesoscale Discussions in Wisconsin, 2021Mesoscale Discussions in Michigan, 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.