Alert archive / Wisconsin / Mesoscale Discussions in 2010

Mesoscale Discussion 421

April 30, 201015 counties in Illinois; 27 counties in Wisconsin

The Storm Prediction Center issued this mesoscale discussion at Apr 30, 2010, 12:41 PM CDT for 15 counties in Illinois; 27 counties in Wisconsin. It was in force for 64 min.

The area

The outline as issued.

The facts

Issued
Apr 30, 2010, 12:41 PM CDT (17:41 UTC)
Expired
Apr 30, 2010, 1:45 PM CDT
In force
64 min
Issued by
the Storm Prediction Center
All 42 counties

Boone County, IL, Bureau County, IL, Carroll County, IL, DeKalb County, IL, Grundy County, IL, Jo Daviess County, IL, Kane County, IL, Kendall County, IL, LaSalle County, IL, Lee County, IL, McHenry County, IL, Ogle County, IL, Stephenson County, IL, Whiteside County, IL, Winnebago County, IL, Adams County, WI, Brown County, WI, Calumet County, WI, Columbia County, WI, Dane County, WI, Dodge County, WI, Fond du Lac County, WI, Green County, WI, Green Lake County, WI, Iowa County, WI, Jefferson County, WI, Lafayette County, WI, Langlade County, WI, Marquette County, WI, Menominee County, WI, Oconto County, WI, Outagamie County, WI, Portage County, WI, Rock County, WI, Sauk County, WI, Shawano County, WI, Walworth County, WI, Washington County, WI, Waukesha County, WI, Waupaca County, WI, Waushara County, WI, Winnebago County, WI

The radar

The Milwaukee radar (KMKX), 66 km from the middle of the area, began a volume at 17:44 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

Davenport, (KDVN), launched 12:00Z, 5.7 hours before the alert went out and 171 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 2010-04-30Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 5 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 2010-04-30The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 332 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
5 J/kg
Mixed-layer CIN
-330 J/kg
Mixed-layer LCL
1205 m above ground
0-6 km bulk shear
55 kt
0-1 km storm-relative helicity
332 m²/s²
0-3 km storm-relative helicity
351 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.3

Open this sounding in Storm Lab

The text

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

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SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Apr 30, 9:18 AM CDTMesoscale DiscussionSPCAdams, Hancock, Henderson, Mercer, Rock Island57 min
Apr 30, 1:05 PM CDTTornado WatchSPCBoone, Bureau, Carroll, Cook, DeKalb, DuPage and 28 more9 hr
Apr 30, 2:08 PM CDTMesoscale DiscussionSPCAdams, Brown, Calhoun, Cass, Fulton, Greene and 13 more67 min
Apr 30, 2:40 PM CDTTornado WatchSPCAdams, Bond, Brown, Calhoun, Cass, Christian and 29 more6 hr
Apr 30, 2:41 PM CDTMesoscale DiscussionSPCBoone, Bureau, Carroll, DeKalb, Henderson, Henry and 17 more64 min
Apr 30, 5:37 PM CDTMesoscale DiscussionSPCBoone, Bureau, Carroll, DeKalb, Henry, Jo Daviess and 16 more53 min
Apr 30, 12:01 PM CDTMesoscale DiscussionSPCAdams, Barron, Buffalo, Chippewa, Clark, Crawford and 28 more29 min
Apr 30, 12:23 PM CDTSevere Thunderstorm WatchSPCAdams, Ashland, Barron, Bayfield, Buffalo, Burnett and 27 more6 hr
Apr 30, 4:59 PM CDTMesoscale DiscussionSPCFlorence, Forest, Langlade, Lincoln, Marinette, Menominee and 2 more61 min

Nearby

Mesoscale Discussions in Wisconsin, 2010Mesoscale Discussions in Illinois, 2010Every mesoscale discussion in 2010

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.