Alert archive / Wisconsin / Mesoscale Discussions in 2021

Mesoscale Discussion 2038

December 15, 202120 counties in Wisconsin

The Storm Prediction Center issued this mesoscale discussion at Dec 15, 2021, 9:03 PM CST for 20 counties in Wisconsin. It was in force for 117 min.

The area

The outline as issued.

The facts

Issued
Dec 15, 2021, 9:03 PM CST (03:03 UTC)
Expired
Dec 15, 2021, 11:00 PM CST
In force
117 min
Issued by
the Storm Prediction Center
Concerning
Tornado watch 565

Counties Barron County, WI, Chippewa County, WI, Clark County, WI, Eau Claire County, WI, Forest County, WI, Langlade County, WI, Lincoln County, WI, Marathon County, WI, Menominee County, WI, Oneida County, WI, Portage County, WI, Price County, WI, Rusk County, WI, Sawyer County, WI, Shawano County, WI, Taylor County, WI, Vilas County, WI, Washburn County, WI, Waupaca County, WI, Wood County, WI

The radar

The Green Bay radar (KGRB), 176 km from the middle of the area, began a volume at 03:05 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 watches that followed

Watches SPC issued over any of the same counties within four hours of this discussion.

The nearest sounding before it

Green Bay/Straub, WI (KGRB), launched 00:00Z, 3.1 hours before the alert went out and 177 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 2021-12-16Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 29 joules per kilogram.LCLLFCEL10008507005003002001001 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 2021-12-16The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 689 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
29 J/kg
Mixed-layer CIN
-469 J/kg
Mixed-layer LCL
505 m above ground
0-6 km bulk shear
60 kt
0-1 km storm-relative helicity
689 m²/s²
0-3 km storm-relative helicity
687 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

373 
ACUS11 KWNS 160303
SWOMCD
SPC MCD 160303 
WIZ000-MIZ000-160500-

Mesoscale Discussion 2038
NWS Storm Prediction Center Norman OK
0903 PM CST Wed Dec 15 2021

Areas affected...north-central Wisconsin

Concerning...Tornado Watch 565...

Valid 160303Z - 160500Z

The severe weather threat for Tornado Watch 565 continues.

SUMMARY...A severe wind risk may eventually push into northern
Wisconsin this evening, and a new watch may need to be considered
depending on storm trends.

DISCUSSION...The northern end of a long-lived squall line continues
to produce severe gusts and damage this evening, moving from
southeast MN into western WI. Currently, this section of the line is
oriented favorably (more perpendicular) to the winds aloft, aiding
storm speed and forward tilt. 

Surface analysis shows that the line is near the warm front, with
temperatures cooling back into the mid 50s F northeast of the
storms. Very strong southerly winds exist just off the surface, and
this is likely aiding elevated instability north of the warm front. 


Given the organization of the line of storms and continued warm
advection profiles, some wind threat may persist into north-central
or even northern WI this evening. Storm trends are currently being
monitored, and a new watch or extension may be needed.

..Jewell.. 12/16/2021

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

ATTN...WFO...MQT...GRB...DLH...ARX...MPX...

LAT...LON   44539108 45009184 45439204 45829194 46239113 46208943
            46118888 45838846 45458844 44938849 44578864 44328917
            44349054 44539108

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Dec 15, 7:11 PM CSTMesoscale DiscussionSPCBuffalo, Crawford, La Crosse, Trempealeau2 hr
Dec 15, 9:44 PM CSTSevere Thunderstorm WatchSPCBrown, Calumet, Columbia, Dane, Dodge, Door and 22 more3 hr

Nearby

Mesoscale 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.