Alert archive / Illinois / Winter Storm Warnings in 2015

Winter Storm Warning 5, NWS Chicago, IL

November 20, 201511 counties in Illinois; Lake County, Porter County, Indiana

NWS Chicago, IL issued this winter storm warning at Nov 20, 2015, 3:24 AM CST for 11 counties in Illinois; Lake County, Porter County, Indiana. It took effect at Nov 20, 2015, 6:00 PM CST. It was in force for 26 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 20, 2015, 3:24 AM CST (09:24 UTC)
In effect from: Nov 20, 2015, 6:00 PM CST
Expired: Nov 21, 2015, 8:00 PM CST
In force: 26 hr
Issued by: NWS Chicago, IL

Counties Boone County, IL, DeKalb County, IL, DuPage 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, Lake County, IN, Porter County, IN

The radar

The Chicago radar (KLOT), 45 km from the middle of the area, began a volume at 09:29 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 00:00Z, 9.4 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: 0 J/kg
Mixed-layer CIN: No buoyant parcel
Mixed-layer LCL: 1456 m above ground
0-6 km bulk shear: 43 kt
0-1 km storm-relative helicity: 177 m²/s²
0-3 km storm-relative helicity: 235 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 20, 3:03 AM CST, 21 minutes earlier.

Area forecast discussion, Nov 20, 3:03 AM CST, 21 minutes before

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Hazardous weather outlook, Nov 19, 6:00 PM CST, 9 hours 24 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 19, 9:46 PM CST	Small Craft Advisory	LOT		17 hr
Nov 20, 3:24 AM CST	Winter Weather Advisory	LOT	Ford, Grundy, Iroquois, Kankakee, Livingston	41 hr
Nov 20, 3:17 PM CST	Gale Watch	LOT		6 hr

Nearby

Winter Storm Warnings in Illinois, 2015 Winter Storm Warnings in Indiana, 2015 Every winter storm warning in 2015

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.