Alert archive / Wisconsin / Mesoscale Discussions in 2012

Mesoscale Discussion 2193

December 20, 201237 counties in Wisconsin

The Storm Prediction Center issued this mesoscale discussion at Dec 20, 2012, 11:28 AM CST for 37 counties in Wisconsin. It was in force for 6 hr.

The area

The outline as issued.

The facts

Issued: Dec 20, 2012, 11:28 AM CST (17:28 UTC)
Expired: Dec 20, 2012, 5:30 PM CST
In force: 6 hr
Issued by: the Storm Prediction Center

All 37 counties

Adams County, WI, Brown County, WI, Calumet County, WI, Columbia County, WI, Crawford County, WI, Dane County, WI, Dodge County, WI, Door County, WI, Fond du Lac County, WI, Grant County, WI, Green County, WI, Green Lake County, WI, Iowa County, WI, Jefferson County, WI, Juneau County, WI, Kewaunee County, WI, Lafayette County, WI, Langlade County, WI, Manitowoc County, WI, Marathon County, WI, Marinette County, WI, Marquette County, WI, Menominee County, WI, Monroe County, WI, Oconto County, WI, Outagamie County, WI, Portage County, WI, Richland County, WI, Rock County, WI, Sauk County, WI, Shawano County, WI, Vernon County, WI, Washington County, WI, Waupaca County, WI, Waushara County, WI, Winnebago County, WI, Wood County, WI

The radar

The Milwaukee radar (KMKX), 111 km from the middle of the area, began a volume at 17:31 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, 5.5 hours before the alert went out and 146 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 467 m above ground
0-6 km bulk shear: 59 kt
0-1 km storm-relative helicity: 202 m²/s²
0-3 km storm-relative helicity: 732 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

606 
ACUS11 KWNS 201728
SWOMCD
SPC MCD 201728 
WIZ000-MIZ000-ILZ000-IAZ000-202330-

MESOSCALE DISCUSSION 2193
NWS STORM PREDICTION CENTER NORMAN OK
1128 AM CST THU DEC 20 2012

AREAS AFFECTED...CNTRL/ERN/SRN WI...FAR NERN IA...PARTS OF FAR NRN
IL...FAR SRN PART OF THE UPPER PENINSULA OF MI

CONCERNING...BLIZZARD 

VALID 201728Z - 202330Z

SUMMARY...BLIZZARD CONDITIONS WILL OVERSPREAD THE AREA THIS
AFTERNOON.

DISCUSSION...FRONTOGENESIS WITHIN THE DEFORMATION ZONE OF THE LARGE
EXTRATROPICAL CYCLONE OVER THE SWRN GREAT LAKES REGION IS BEING
LOCALLY ENHANCED INVOF A SECONDARY VORT MAX NEARING THE W END OF
LAKE MICHIGAN N OF CHICAGO PER WATER VAPOR LOOPS. MODERATE TO
LOCALLY HEAVY SNOW IS ONGOING ACROSS PARTS OF CNTRL/SRN WI...AND
SNOWFALL INTENSITY WILL INCREASE AS A 985-MB SFC LOW N OF PEORIA IL
DEEPENS AND TRACKS TOWARD CHICAGO. SNOWFALL RATES OF 1-1.5 IN/HR
WILL BECOME LIKELY BY 1830-1900Z...HIGHEST SE OF A LINE FROM AROUND
GREEN BAY WI TO FAR NERN IA. CONVECTIVELY ENHANCED SNOW RATES MAY
OCCUR IN ASSOCIATION WITH NARROW ELEVATED CAPE LAYERS PER FORECAST
SOUNDINGS...WHICH MAY SUPPORT AN ISOLATED LIGHTNING STRIKE OR TWO.

NNELY TO NWLY WINDS WILL CONTINUE TO STRENGTHEN OWING TO THE
TIGHTENING SFC PRESSURE GRADIENT OVER THE WRN/NRN QUADRANTS OF THE
SFC LOW...WITH SPEEDS OF 25-35 MPH AND GUSTS REACHING 40-50 MPH
BECOMING COMMON BY 20Z. THE STRONGEST WINDS MAY...AT TIMES...LAG
SLIGHTLY TO THE W OF THE HIGHEST SNOWFALL RATES. HOWEVER...EVEN
LIGHT SNOW AND FRESHLY FALLEN SNOW WILL COMBINE WITH THE STRONG
WINDS TO CREATE BLIZZARD CONDITIONS WITH VISIBILITIES BELOW
ONE-QUARTER MILE.

..COHEN.. 12/20/2012

...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...

ATTN...WFO...MQT...GRB...LOT...MKX...DVN...ARX...

LAT...LON   43049136 43299129 44129082 45188947 45558791 45468697
            44948695 44118757 42778851 42478929 42409016 42439070
            42599108 43049136

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Dec 20, 3:12 AM CST	Mesoscale Discussion	SPC	Adams, Clark, Columbia, Crawford, Grant, Green Lake and 18 more	4 hr

Nearby

Mesoscale Discussions in Wisconsin, 2012 Every mesoscale discussion in 2012

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.