Alert archive / Illinois / Freeze Warnings in 2012

Freeze Warning 3, NWS Chicago, IL

April 10, 201216 counties in Illinois; 5 counties in Indiana

NWS Chicago, IL issued this freeze warning at Apr 10, 2012, 3:36 AM CDT for 16 counties in Illinois; 5 counties in Indiana. It took effect at Apr 11, 2012, 1:00 AM CDT. It was in force for 7 hr. 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 10, 2012, 3:36 AM CDT (08:36 UTC)
In effect from: Apr 11, 2012, 1:00 AM CDT
Expired: Apr 11, 2012, 8:00 AM CDT
In force: 7 hr
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 08:39 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

Lincoln, IL (KILX), launched 00:00Z, 8.6 hours before the alert went out and 156 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: 3414 m above ground
0-6 km bulk shear: 61 kt
0-1 km storm-relative helicity: 62 m²/s²
0-3 km storm-relative helicity: 96 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 10, 3:05 AM CDT, 31 minutes earlier.

Area forecast discussion, Apr 10, 3:05 AM CDT, 31 minutes before

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Hazardous weather outlook, Apr 9, 8:29 PM CDT, 7 hours 7 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 10, 3:36 AM CDT	Freeze Watch	LOT	DuPage, Iroquois, Kane, Kankakee, Kendall, Lake and 1 more	11 hr
Apr 10, 4:27 AM CDT	Fire Weather Watch	LOT	Ford, Grundy, Iroquois, Kankakee, Kendall, LaSalle and 2 more	3 hr
Apr 10, 7:34 AM CDT	Red Flag Warning	LOT	Ford, Grundy, Iroquois, Kankakee, Kendall, LaSalle and 2 more	11 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.