Alert archive / Wisconsin / Mesoscale Discussions in 2020

Mesoscale Discussion 113

February 9, 202029 counties in Wisconsin

The Storm Prediction Center issued this mesoscale discussion at Feb 9, 2020, 10:56 AM CST for 29 counties in Wisconsin. It was in force for 5 hr.

The area

The outline as issued.

The facts

Issued
Feb 9, 2020, 10:56 AM CST (16:56 UTC)
Expired
Feb 9, 2020, 4:00 PM CST
In force
5 hr
Issued by
the Storm Prediction Center
All 29 counties

Adams County, WI, Brown County, WI, Calumet County, WI, Columbia County, WI, Dane County, WI, Dodge County, WI, Fond du Lac County, WI, Green Lake County, WI, Jackson County, WI, Jefferson County, WI, Juneau County, WI, La Crosse County, WI, Manitowoc County, WI, Marquette County, WI, Milwaukee County, WI, Monroe County, WI, Outagamie County, WI, Ozaukee County, WI, Portage County, WI, Richland County, WI, Sauk County, WI, Sheboygan County, WI, Vernon County, WI, Washington County, WI, Waukesha County, WI, Waupaca County, WI, Waushara County, WI, Winnebago County, WI, Wood County, WI

The radar

The Milwaukee radar (KMKX), 105 km from the middle of the area, began a volume at 16:55 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, 4.9 hours before the alert went out and 123 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 2020-02-09Temperature 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, Green Bay/Straub, WI at 12:00Z on 2020-02-09The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 97 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
1820 m above ground
0-6 km bulk shear
59 kt
0-1 km storm-relative helicity
97 m²/s²
0-3 km storm-relative helicity
66 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

176 
ACUS11 KWNS 091657
SWOMCD
SPC MCD 091656 
WIZ000-092200-

Mesoscale Discussion 0113
NWS Storm Prediction Center Norman OK
1056 AM CST Sun Feb 09 2020

Areas affected...Most of central Wisconsin

Concerning...Heavy snow 

Valid 091656Z - 092200Z

SUMMARY...Heavy snow will continue across much of central Wisconsin,
with 1 inch/hr snowfall rates possible through mid-afternoon.

DISCUSSION...A relatively small, but progressive mid-level shortwave
trough will continue to translate across the Upper Mississippi
Valley, with a favorable low-level mass response (deep-layer warm
air/moisture advection) and deep-layer ascent continuing to support
heavy snow potential within a precipitation shield now centered over
Wisconsin. KARX and KMKX dual-polarimetric data, ASOS, and public
reports continue to infer heavy snow falling across the area. Latest
Mesoanalysis and RAP forecast soundings also depict a near saturated
low- to mid-level vertical profile, with strong 1000-850 mb
frontogenesis to enhance ascent within the aforementioned favorable
1000-700 mb WAA/moisture advection regime. Very efficient dendrite
production within a deep, saturated dendritic growth zone will
promote at least modest potential for 1 inch/hr snowfall rates.

09Z SREF, 12Z HREF, and 15Z HRRR all depict heavy snow continuing
across central Wisconsin through at least 21Z. Thereafter, the rapid
eastward propagation of the aforementioned shortwave and associated
moisture advection axis will shift east, promoting a gradual decline
in snowfall intensity.

..Squitieri.. 02/09/2020

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

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

LAT...LON   42888939 43179076 43429111 43949128 44339092 44719024
            44858912 44668813 44308752 43708740 43208749 42858772
            42888939

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Feb 9, 6:39 AM CSTMesoscale DiscussionSPCAdams, Buffalo, Chippewa, Clark, Columbia, Crawford and 19 more4 hr

Nearby

Mesoscale Discussions in Wisconsin, 2020Every mesoscale discussion in 2020

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.