Alert archive / Illinois / Winter Weather Advisories in 2021

Winter Weather Advisory 9, NWS Quad Cities, IA

February 6, 202110 counties in Illinois

NWS Quad Cities, IA issued this winter weather advisory at Feb 6, 2021, 9:23 AM CST for 10 counties in Illinois. It took effect at Feb 6, 2021, 12:00 PM CST. It was in force for 8 hr.

The area

The counties it named.

The facts

Issued
Feb 6, 2021, 9:23 AM CST (15:23 UTC)
In effect from
Feb 6, 2021, 12:00 PM CST
Expired
Feb 6, 2021, 7:33 PM CST
In force
8 hr
Issued by
NWS Quad Cities, IA

Counties Bureau County, IL, Hancock County, IL, Henderson County, IL, Henry County, IL, McDonough County, IL, Mercer County, IL, Putnam County, IL, Rock Island County, IL, Warren County, IL, Whiteside County, IL

The radar

The Quad Cities radar (KDVN), 61 km from the middle of the area, began a volume at 15:23 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, 3.4 hours before the alert went out and 419 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-pSkew-T log-p diagram, Green Bay/Straub, WI at 12:00Z on 2021-02-06Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Green Bay/Straub, WI at 12:00Z on 2021-02-06The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 96 square meters per square second.19395878Sfc1 km3 km6 km9 kmRMLM
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
826 m above ground
0-6 km bulk shear
64 kt
0-1 km storm-relative helicity
96 m²/s²
0-3 km storm-relative helicity
152 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The office that day

Everything else NWS Quad Cities, IA issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Feb 6, 12:51 AM CSTWind Chill AdvisoryDVNBenton, Buchanan, Cedar, Clinton, Delaware, Dubuque and 5 more9 hr
Feb 6, 3:47 AM CSTWind Chill WarningDVNBenton, Buchanan, Cedar, Clinton, Delaware, Dubuque and 10 more32 hr
Feb 6, 3:47 AM CSTWind Chill AdvisoryDVNDes Moines, Henry, Jefferson, Keokuk, Lee, Louisa and 4 more32 hr

Nearby

Winter Weather Advisories in Illinois, 2021Every winter weather advisory 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.