Alert archive / Wisconsin / Mesoscale Discussions in 2021

Mesoscale Discussion 1280

July 14, 20214 states

The Storm Prediction Center issued this mesoscale discussion at Jul 14, 2021, 11:45 AM CDT for 4 states. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued
Jul 14, 2021, 11:45 AM CDT (16:45 UTC)
Expired
Jul 14, 2021, 1:45 PM CDT
In force
2 hr
Issued by
the Storm Prediction Center
Concerning
Severe thunderstorm watch 377
All 43 counties

Allamakee County, IA, Clayton County, IA, Dubuque County, IA, Jackson County, IA, Jones County, IA, Boone County, IL, Carroll County, IL, Jo Daviess County, IL, McHenry County, IL, Ogle County, IL, Stephenson County, IL, Winnebago County, IL, Houston County, MN, Winona County, MN, Adams County, WI, Calumet County, WI, Columbia County, WI, Crawford County, WI, Dane County, WI, Dodge 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, Kenosha County, WI, La Crosse County, WI, Lafayette County, WI, Marquette County, WI, Milwaukee County, WI, Monroe County, WI, Racine County, WI, Richland County, WI, Rock County, WI, Sauk County, WI, Vernon County, WI, Walworth County, WI, Washington County, WI, Waukesha County, WI, Waushara County, WI, Winnebago County, WI

The radar

The Milwaukee radar (KMKX), 107 km from the middle of the area, began a volume at 16:48 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

Davenport, (KDVN), launched 12:00Z, 4.8 hours before the alert went out and 175 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, Davenport, at 12:00Z on 2021-07-14Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 573 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, Davenport, at 12:00Z on 2021-07-14The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 108 square meters per square second.19395878Sfc1 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
573 J/kg
Mixed-layer CIN
-62 J/kg
Mixed-layer LCL
1106 m above ground
0-6 km bulk shear
34 kt
0-1 km storm-relative helicity
108 m²/s²
0-3 km storm-relative helicity
139 m²/s²
Significant tornado parameter
0.0
Supercell composite
1.1

Open this sounding in Storm Lab

The text

As transmitted.

232 
ACUS11 KWNS 141645
SWOMCD
SPC MCD 141645 
WIZ000-ILZ000-IAZ000-MNZ000-141845-

Mesoscale Discussion 1280
NWS Storm Prediction Center Norman OK
1145 AM CDT Wed Jul 14 2021

Areas affected...eastern Iowa...southern Wisconsin

Concerning...Severe Thunderstorm Watch 377...

Valid 141645Z - 141845Z

The severe weather threat for Severe Thunderstorm Watch 377
continues.

SUMMARY...The threat for isolated strong gusts or marginal hail
continues mainly from northeast Iowa into southwest Wisconsin. It is
unclear if another watch will be needed in the short term.

DISCUSSION...A north-south oriented band of storms continues
eastward across the watch and is now crossing the MS River. This
activity is associated with the leading warm advection ahead of the
midlevel wave, with veered low-level winds across central IA feeding
instability eastward. 

Objective analysis shows less instability ahead of the system
compared to farther west, but continued theta-e advection and areas
of filtered sunshine may aid destabilization enough for some of this
activity to become severe. While an additional watch is not
anticipated in the near term downstream of this ongoing line, trends
will continue to be monitored for strengthening.

..Jewell.. 07/14/2021

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

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

LAT...LON   44009182 44398875 44278832 43928802 43328783 42908769
            42578772 42338785 42088848 41949035 42009112 42129139
            42599134 43139136 43649174 43899184 44009182

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jul 14, 7:02 AM CDTMesoscale DiscussionSPCJo Daviess, Stephenson2 hr
Jul 14, 2:01 PM CDTMesoscale DiscussionSPCBoone, Bureau, Carroll, Cook, DeKalb, DuPage and 9 more119 min
Jul 14, 5:42 PM CDTMesoscale DiscussionSPCCarroll, Jo Daviess, Stephenson, Winnebago63 min
Jul 14, 6:13 PM CDTTornado WatchSPCCarroll, Jo Daviess, Rock Island, Stephenson, Whiteside6 hr
Jul 14, 8:54 AM CDTSevere Thunderstorm WatchSPCAllamakee, Black Hawk, Bremer, Buchanan, Butler, Cerro Gordo and 13 more5 hr
Jul 14, 1:40 PM CDTMesoscale DiscussionSPCAudubon, Black Hawk, Boone, Bremer, Buena Vista, Butler and 38 more2 hr
Jul 14, 2:35 PM CDTTornado WatchSPCAudubon, Benton, Black Hawk, Boone, Bremer, Buchanan and 41 more8 hr
Jul 14, 4:17 PM CDTMesoscale DiscussionSPCBoone, Butler, Calhoun, Franklin, Greene, Grundy and 5 more58 min
Jul 14, 5:47 PM CDTMesoscale DiscussionSPCAudubon, Benton, Black Hawk, Boone, Bremer, Buchanan and 29 more118 min

Nearby

Mesoscale Discussions in Wisconsin, 2021Mesoscale Discussions in Illinois, 2021Mesoscale Discussions in Iowa, 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.