Alert archive / Illinois / Winter Storm Watches in 2021

Winter Storm Watch 1, NWS Chicago, IL

January 24, 202114 counties in Illinois; Lake County, Indiana

NWS Chicago, IL issued this winter storm watch at Jan 24, 2021, 3:05 AM CST for 14 counties in Illinois; Lake County, Indiana. It took effect at Jan 25, 2021, 12:00 PM CST. It was in force for .

The area

The counties it named.

The facts

Issued: Jan 24, 2021, 3:05 AM CST (09:05 UTC)
In effect from: Jan 25, 2021, 12:00 PM CST
Expired: Jan 24, 2021, 2:55 PM CST
In force
Issued by: NWS Chicago, IL

Counties Boone County, IL, Cook 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, Will County, IL, Winnebago County, IL, Lake County, IN

The radar

The Chicago radar (KLOT), 42 km from the middle of the area, began a volume at 09:08 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 00:00Z, 9.1 hours before the alert went out and 171 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: 1824 m above ground
0-6 km bulk shear: 55 kt
0-1 km storm-relative helicity: 217 m²/s²
0-3 km storm-relative helicity: 347 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 watch 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 watch went out at Jan 23, 10:53 PM CST, 4 hours 12 minutes earlier.

Area forecast discussion, Jan 23, 10:53 PM CST, 4 hours 12 minutes before

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Hazardous weather outlook, Jan 23, 4:40 PM CST, 10 hours 25 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
Jan 24, 2:48 PM CST	Gale Watch	LOT		6 hr
Jan 24, 2:55 PM CST	Winter Storm Warning	LOT	Boone, Cook, DeKalb, DuPage, Grundy, Kane and 8 more	48 hr
Jan 24, 2:55 PM CST	Winter Weather Advisory	LOT	Cook, Ford, Grundy, Iroquois, Kankakee, Kendall and 3 more	48 hr
Jan 24, 3:08 PM CST	Lakeshore Flood Advisory	LOT	Cook, Lake	45 hr

Nearby

Winter Storm Watches in Illinois, 2021 Winter Storm Watches in Indiana, 2021 Every winter storm watch in 2021

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.