Alert archive / Iowa / Mesoscale Discussions in 2020

Mesoscale Discussion 257

March 28, 2020Carroll County, Jo Daviess County, Stephenson County, Illinois; 7 counties in Iowa; 4 counties in Wisconsin

The Storm Prediction Center issued this mesoscale discussion at Mar 28, 2020, 6:42 PM CDT for Carroll County, Jo Daviess County, Stephenson County, Illinois; 7 counties in Iowa; 4 counties in Wisconsin. It was in force for 93 min.

The area

The outline as issued.

The facts

Issued: Mar 28, 2020, 6:42 PM CDT (23:42 UTC)
Expired: Mar 28, 2020, 8:15 PM CDT
In force: 93 min
Issued by: the Storm Prediction Center

Counties Buchanan County, IA, Clayton County, IA, Delaware County, IA, Dubuque County, IA, Jackson County, IA, Jones County, IA, Linn County, IA, Carroll County, IL, Jo Daviess County, IL, Stephenson County, IL, Grant County, WI, Green County, WI, Iowa County, WI, Lafayette County, WI

The radar

The Quad Cities radar (KDVN), 111 km from the middle of the area, began a volume at 23:44 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.

Tornado Watch 73Mar 28, 8:40 PM CDT

The nearest sounding before it

Davenport, (KDVN), launched 12:00Z, 11.7 hours before the alert went out and 111 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: 695 m above ground
0-6 km bulk shear: 72 kt
0-1 km storm-relative helicity: -128 m²/s²
0-3 km storm-relative helicity: 164 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

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SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Mar 27, 8:02 PM CDT	Mesoscale Discussion	SPC	Edwards, Franklin, Hamilton, Jackson, Jefferson, Lawrence and 10 more	88 min
Mar 27, 8:33 PM CDT	Mesoscale Discussion	SPC	Calhoun	87 min
Mar 27, 10:16 PM CDT	Severe Thunderstorm Watch	SPC	Bond, Calhoun, Christian, Effingham, Fayette, Greene and 9 more	6 hr
Mar 27, 11:46 PM CDT	Mesoscale Discussion	SPC	Bond, Calhoun, Christian, Fayette, Greene, Jersey and 8 more	89 min
Mar 28, 1:34 AM CDT	Mesoscale Discussion	SPC	Carroll, Henry, Jo Daviess, Mercer, Rock Island, Whiteside	56 min
Mar 28, 10:18 AM CDT	Mesoscale Discussion	SPC	Champaign, Christian, DeWitt, Douglas, Ford, Iroquois and 8 more	2 hr
Mar 28, 1:17 PM CDT	Mesoscale Discussion	SPC	Alexander, Bond, Clark, Clay, Clinton, Crawford and 34 more	88 min
Mar 28, 1:33 PM CDT	Mesoscale Discussion	SPC	Adams, Hancock, Henderson	117 min
Mar 28, 2:45 PM CDT	Tornado Watch PDS	SPC	Adams, Brown, Bureau, Calhoun, Cass, Champaign and 44 more	6 hr
Mar 28, 3:53 PM CDT	Tornado Watch	SPC	Alexander, Bond, Clark, Clay, Clinton, Crawford and 30 more	5 hr
Mar 28, 4:59 PM CDT	Mesoscale Discussion	SPC	Gallatin, Hamilton, Hardin, Johnson, Massac, Pope and 2 more	61 min
Mar 28, 5:21 PM CDT	Mesoscale Discussion	SPC	Brown, Fulton, Hancock, Henderson, Henry, Knox and 7 more	84 min

Nearby

Mesoscale Discussions in Iowa, 2020 Mesoscale Discussions in Wisconsin, 2020 Mesoscale Discussions in Illinois, 2020 Every 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.