Alert archive / Michigan / Mesoscale Discussions in 2021

Mesoscale Discussion 2007

December 11, 20215 counties in Michigan

The Storm Prediction Center issued this mesoscale discussion at Dec 11, 2021, 12:46 AM EST for 5 counties in Michigan. It was in force for 3 hr.

The area

The outline as issued.

The facts

Issued
Dec 11, 2021, 12:46 AM EST (05:46 UTC)
Expired
Dec 11, 2021, 3:45 AM EST
In force
3 hr
Issued by
the Storm Prediction Center
Concerning
Heavy snow

Counties Alger County, MI, Baraga County, MI, Dickinson County, MI, Iron County, MI, Marquette County, MI

The radar

The Marquette radar (KMQT), 11 km from the middle of the area, began a volume at 05:49 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 00:00Z, 5.8 hours before the alert went out and 224 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 00:00Z on 2021-12-11Temperature 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, Green Bay/Straub, WI at 00:00Z on 2021-12-11The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 392 square meters per square second.1939587897117Sfc1 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
1166 m above ground
0-6 km bulk shear
82 kt
0-1 km storm-relative helicity
392 m²/s²
0-3 km storm-relative helicity
890 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

637 
ACUS11 KWNS 110547
SWOMCD
SPC MCD 110546 
MIZ000-110845-

Mesoscale Discussion 2007
NWS Storm Prediction Center Norman OK
1146 PM CST Fri Dec 10 2021

Areas affected...portions of the Upper Peninsula of Michigan

Concerning...Heavy snow 

Valid 110546Z - 110845Z

SUMMARY...Up to 1 inch/hr snowfall rates are expected across
portions of the Upper Peninsula of Michigan for at least a few
hours.

DISCUSSION...A 992 mb surface low across northern IL is tracking
northeast, with a warm conveyer belt of deep moisture wrapping
around the low. Strong 700 mb frontogenesis has been noted across
the Upper Michigan Peninsula at the nose of a WAA axis, contributing
to rapid ascent of moisture into a deep dendritic growth zone. As
such, up to 1 inch/hr snowfall rates may accompany the stronger
snowfall bands for at least a few more hours.

..Squitieri/Grams.. 12/11/2021

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

ATTN...WFO...MQT...

LAT...LON   46588921 46858830 46848753 46788604 46578573 46368602
            46128638 45988693 45998785 46238901 46588921

Nearby

Mesoscale 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.