Alert archive / Illinois / Winter Storm Warnings in 2020
Winter Storm Warning 2, NWS Chicago, IL
NWS Chicago, IL issued this winter storm warning at Dec 28, 2020, 3:04 PM CST for 9 counties in Illinois. It took effect at Dec 29, 2020, 2:43 PM CST. It was in force for 18 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
- Dec 28, 2020, 3:04 PM CST (21:04 UTC)
- In effect from
- Dec 29, 2020, 2:43 PM CST
- Expired
- Dec 30, 2020, 9:00 AM CST
- In force
- 18 hr
- Issued by
- NWS Chicago, IL
Counties Boone County, IL, Cook County, IL, DeKalb County, IL, Kane County, IL, Lake County, IL, Lee County, IL, McHenry County, IL, Ogle County, IL, Winnebago County, IL
The radar
The Chicago radar (KLOT), 71 km from the middle of the area, began a volume at 21:08 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 12:00Z, 9.1 hours before the alert went out and 163 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.
- Mixed-layer CAPE
- 0 J/kg
- Mixed-layer CIN
- No buoyant parcel
- Mixed-layer LCL
- 627 m above ground
- 0-6 km bulk shear
- 65 kt
- 0-1 km storm-relative helicity
- -126 m²/s²
- 0-3 km storm-relative helicity
- -52 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
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 Dec 28, 3:04 PM CST, 0 minutes earlier.
Area forecast discussion, Dec 28, 3:04 PM CST, 0 minutes before
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</html>The office that day
Everything else NWS Chicago, IL issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Dec 28, 3:31 AM CST | Winter Storm Watch | LOT | Boone, Ogle, Winnebago | 12 hr |
| Dec 28, 3:04 PM CST | Winter Weather Advisory | LOT | Cook, DeKalb, DuPage, Grundy, Kane, Kankakee and 7 more | 39 hr |
Nearby
Winter Storm Warnings in Illinois, 2020Every winter storm warning in 2020
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.