Alert archive / Illinois / Winter Storm Warnings in 2018

Winter Storm Warning 3, NWS Chicago, IL

November 24, 201812 counties in Illinois

NWS Chicago, IL issued this winter storm warning at Nov 24, 2018, 1:44 PM CST for 12 counties in Illinois. It took effect at Nov 25, 2018, 8:00 AM CST. It was in force for 25 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: Nov 24, 2018, 1:44 PM CST (19:44 UTC)
In effect from: Nov 25, 2018, 8:00 AM CST
Expired: Nov 26, 2018, 9:00 AM CST
In force: 25 hr
Issued by: NWS Chicago, IL

Counties Boone County, IL, DeKalb County, IL, DuPage County, IL, Grundy County, IL, Kane County, IL, Kendall County, IL, Lake County, IL, LaSalle County, IL, Lee County, IL, McHenry County, IL, Ogle County, IL, Winnebago County, IL

The radar

The Chicago radar (KLOT), 59 km from the middle of the area, began a volume at 19:46 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

Green Bay/Straub, WI (KGRB), launched 12:00Z, 7.7 hours before the alert went out and 288 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: 2 J/kg
Mixed-layer CIN: 0 J/kg
Mixed-layer LCL: 494 m above ground
0-6 km bulk shear: 24 kt
0-1 km storm-relative helicity: 30 m²/s²
0-3 km storm-relative helicity: 26 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 winter storm 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 winter storm warning went out at Nov 24, 11:51 AM CST, 1 hour 53 minutes earlier.

Area forecast discussion, Nov 24, 11:51 AM CST, 1 hour 53 minutes before

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Hazardous weather outlook, Nov 24, 10:00 AM CST, 3 hours 44 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
Nov 24, 3:09 AM CST	Gale Watch	LOT		12 hr
Nov 24, 1:44 PM CST	Winter Weather Advisory	LOT	Kankakee, Livingston	46 hr
Nov 24, 3:28 PM CST	Gale Warning	LOT		45 hr
Nov 24, 3:28 PM CST	Small Craft Advisory	LOT		27 hr

Nearby

Winter Storm Warnings in Illinois, 2018 Every winter storm warning in 2018

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.