Alert archive / Illinois / Mesoscale Discussions in 2004

Mesoscale Discussion 1706

July 16, 20045 states

The Storm Prediction Center issued this mesoscale discussion at Jul 16, 2004, 10:51 AM CDT for 5 states. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued: Jul 16, 2004, 10:51 AM CDT (15:51 UTC)
Expired: Jul 16, 2004, 1:15 PM CDT
In force: 2 hr
Issued by: the Storm Prediction Center

All 71 counties

Cedar County, IA, Clayton County, IA, Clinton County, IA, Delaware County, IA, Dubuque County, IA, Jackson County, IA, Jones County, IA, Muscatine County, IA, Scott County, IA, Boone County, IL, Bureau County, IL, Carroll County, IL, Cook County, IL, DeKalb County, IL, DuPage County, IL, Grundy County, IL, Henry County, IL, Jo Daviess County, IL, Kane County, IL, Kankakee County, IL, Kendall County, IL, Knox County, IL, Lake County, IL, LaSalle County, IL, Lee County, IL, Marshall County, IL, McHenry County, IL, Mercer County, IL, Ogle County, IL, Putnam County, IL, Rock Island County, IL, Stark County, IL, Stephenson County, IL, Warren County, IL, Whiteside County, IL, Will County, IL, Winnebago County, IL, Elkhart County, IN, Kosciusko County, IN, LaGrange County, IN, Lake County, IN, LaPorte County, IN, Marshall County, IN, Noble County, IN, Porter County, IN, Saint Joseph County, IN, Starke County, IN, Allegan County, MI, Barry County, MI, Berrien County, MI, Branch County, MI, Calhoun County, MI, Cass County, MI, Eaton County, MI, Kalamazoo County, MI, Kent County, MI, Ottawa County, MI, Saint Joseph County, MI, Van Buren County, MI, Dane County, WI, Grant County, WI, Green County, WI, Iowa County, WI, Jefferson County, WI, Kenosha County, WI, Lafayette County, WI, Milwaukee County, WI, Racine County, WI, Rock County, WI, Walworth County, WI, Waukesha County, WI

The radar

The Chicago radar (KLOT), 56 km from the middle of the area, began a volume at 15:53 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 647Jul 16, 12:10 PM CDT

The nearest sounding before it

Lincoln, IL (KILX), launched 12:00Z, 3.9 hours before the alert went out and 223 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: 35 J/kg
Mixed-layer CIN: -107 J/kg
Mixed-layer LCL: 1218 m above ground
0-6 km bulk shear: 38 kt
0-1 km storm-relative helicity: 5 m²/s²
0-3 km storm-relative helicity: 116 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
Jul 16, 12:10 PM CDT	Severe Thunderstorm Watch	SPC	Boone, Bureau, Carroll, Cook, DeKalb, DuPage and 33 more	5 hr
Jul 16, 2:45 PM CDT	Mesoscale Discussion	SPC	Boone, Bureau, Carroll, Cook, DeKalb, DuPage and 33 more	90 min
Jul 15, 11:34 PM CDT	Mesoscale Discussion	SPC	Adair, Adams, Audubon, Cass, Decatur, Fremont and 10 more	86 min

Nearby

Mesoscale Discussions in Illinois, 2004 Mesoscale Discussions in Michigan, 2004 Mesoscale Discussions in Wisconsin, 2004 Every mesoscale discussion in 2004

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.