Alert archive / Illinois / Freeze Warnings in 2012

Freeze Warning 6, NWS Chicago, IL

April 22, 201216 counties in Illinois; 5 counties in Indiana

NWS Chicago, IL issued this freeze warning at Apr 22, 2012, 3:36 PM CDT for 16 counties in Illinois; 5 counties in Indiana. It took effect at Apr 23, 2012, 3:00 AM CDT. It was in force for 63 min. No storm report in the archive falls inside the area while it was in force.

The area

The counties it named.

The facts

Issued: Apr 22, 2012, 3:36 PM CDT (20:36 UTC)
In effect from: Apr 23, 2012, 3:00 AM CDT
Expired: Apr 23, 2012, 4:03 AM CDT
In force: 63 min
Issued by: NWS Chicago, IL

All 21 counties

Boone 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, Ogle County, IL, Winnebago County, IL, Benton County, IN, Jasper County, IN, Lake County, IN, Newton County, IN, Porter County, IN

The radar

The Chicago radar (KLOT), 15 km from the middle of the area, began a volume at 20:33 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, 8.6 hours before the alert went out and 190 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: 1586 m above ground
0-6 km bulk shear: 17 kt
0-1 km storm-relative helicity: -43 m²/s²
0-3 km storm-relative helicity: 47 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

What forecasters said that day

The local office's own words before this freeze warning went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Chicago, IL wrote its last area forecast discussion before this freeze warning went out at Apr 22, 3:21 PM CDT, 15 minutes earlier.

Area forecast discussion, Apr 22, 3:21 PM CDT, 15 minutes before

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Hazardous weather outlook, Apr 22, 10:44 AM CDT, 4 hours 52 minutes before

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The office that day

Everything else NWS Chicago, IL issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Apr 22, 3:15 AM CDT	Small Craft Advisory	LOT		49 hr
Apr 22, 5:38 AM CDT	Fire Weather Watch	LOT	Cook, DeKalb, DuPage, Ford, Grundy, Iroquois and 7 more	12 hr
Apr 22, 3:22 PM CDT	Gale Watch	LOT		7 hr
Apr 22, 5:37 PM CDT	Red Flag Warning	LOT	Cook, DeKalb, DuPage, Ford, Grundy, Iroquois and 8 more	25 hr

Nearby

Freeze Warnings in Illinois, 2012 Freeze Warnings in Indiana, 2012 Every freeze warning in 2012

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.