Alert archive / Illinois / Mesoscale Discussions in 2005

Mesoscale Discussion 791

May 9, 200521 counties in Illinois; Newton County, Indiana; 16 counties in Wisconsin

The Storm Prediction Center issued this mesoscale discussion at May 9, 2005, 12:00 PM CDT for 21 counties in Illinois; Newton County, Indiana; 16 counties in Wisconsin. It was in force for 90 min.

The area

The outline as issued.

The facts

Issued: May 9, 2005, 12:00 PM CDT (17:00 UTC)
Expired: May 9, 2005, 1:30 PM CDT
In force: 90 min
Issued by: the Storm Prediction Center

All 38 counties

Boone County, IL, Cook County, IL, DeKalb County, IL, DuPage County, IL, Ford County, IL, Grundy County, IL, Iroquois County, IL, Kane County, IL, Kankakee County, IL, Kendall County, IL, Lake County, IL, LaSalle County, IL, Lee County, IL, Livingston County, IL, McHenry County, IL, McLean County, IL, Ogle County, IL, Putnam County, IL, Stephenson County, IL, Will County, IL, Winnebago County, IL, Newton County, IN, Adams County, WI, Columbia County, WI, Crawford County, WI, Dane County, WI, Green County, WI, Iowa County, WI, Jefferson County, WI, Juneau County, WI, Lafayette County, WI, Marquette County, WI, Monroe County, WI, Richland County, WI, Rock County, WI, Sauk County, WI, Vernon County, WI, Walworth County, WI

The radar

The Milwaukee radar (KMKX), 83 km from the middle of the area, began a volume at 17:02 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.

Severe Thunderstorm Watch 239May 9, 12:45 PM CDT

The nearest sounding before it

Green Bay/Straub, WI (KGRB), launched 12:00Z, 5.0 hours before the alert went out and 247 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: 1034 m above ground
0-6 km bulk shear: 26 kt
0-1 km storm-relative helicity: -56 m²/s²
0-3 km storm-relative helicity: 19 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

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.

Issued	Product	Office	Counties	Lasted
May 9, 12:45 PM CDT	Severe Thunderstorm Watch	SPC	Boone, Bureau, Cook, DeKalb, DuPage, Grundy and 11 more	7 hr
May 9, 3:31 PM CDT	Mesoscale Discussion	SPC	Boone, Cook, DeKalb, DuPage, Grundy, Kane and 9 more	89 min
May 9, 5:32 PM CDT	Mesoscale Discussion	SPC	Boone, Bureau, Cook, DeKalb, DuPage, Grundy and 11 more	28 min
May 8, 7:14 PM CDT	Mesoscale Discussion	SPC	Barron, Buffalo, Burnett, Dunn, Pepin, Pierce and 3 more	2 hr
May 9, 12:58 PM CDT	Mesoscale Discussion	SPC	Barron, Buffalo, Burnett, Chippewa, Clark, Dunn and 11 more	92 min

Nearby

Mesoscale Discussions in Illinois, 2005 Mesoscale Discussions in Wisconsin, 2005 Mesoscale Discussions in Indiana, 2005 Every mesoscale discussion in 2005

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.