Alert archive / Illinois / Winter Storm Watches in 2021

Winter Storm Watch 3, NWS Chicago, IL

February 3, 20214 counties in Illinois

NWS Chicago, IL issued this winter storm watch at Feb 3, 2021, 3:03 AM CST for 4 counties in Illinois. It took effect at Feb 4, 2021, 3:00 PM CST. It was in force for .

The area

The counties it named.

The facts

Issued
Feb 3, 2021, 3:03 AM CST (09:03 UTC)
In effect from
Feb 4, 2021, 3:00 PM CST
Expired
Feb 3, 2021, 2:29 PM CST
In force
Issued by
NWS Chicago, IL

Counties Boone County, IL, Lee County, IL, Ogle County, IL, Winnebago County, IL

The radar

The Chicago radar (KLOT), 105 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 124 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, Davenport, at 00:00Z on 2021-02-03Temperature 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, Davenport, at 00:00Z on 2021-02-03The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 32 square meters per square second.1939587897117Sfc1 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
1014 m above ground
0-6 km bulk shear
53 kt
0-1 km storm-relative helicity
32 m²/s²
0-3 km storm-relative helicity
65 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 Feb 2, 10:45 PM CST, 4 hours 18 minutes earlier.

Area forecast discussion, Feb 2, 10:45 PM CST, 4 hours 18 minutes before
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Hazardous weather outlook, Feb 2, 2:42 PM CST, 12 hours 21 minutes before
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    <section class="card" role="status" aria-live="polite">
      <div class="status" id="status">Temporary Notice</div>
      <h1 id="headline">This service is currently unavailable.</h1>
      <p id="message1">
        The site you requested is temporarily down for maintenance or an unexpected outage.
      </p>
      <p id="message2">
        Please try again in a few minutes.
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The office that day

Everything else NWS Chicago, IL issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Feb 3, 5:47 AM CSTDense Fog AdvisoryLOTBoone, DeKalb, Grundy, Kankakee, LaSalle, Lee and 4 more5 hr
Feb 3, 6:27 AM CSTGale WatchLOT9 hr
Feb 3, 6:27 AM CSTSmall Craft AdvisoryLOT36 hr
Feb 3, 2:29 PM CSTWinter Storm WarningLOTBoone, Lee, Ogle, Winnebago36 hr
Feb 3, 2:29 PM CSTWinter Weather AdvisoryLOTBoone, Cook, DeKalb, DuPage, Grundy, Kane and 10 more46 hr
Feb 3, 3:04 PM CSTGale WarningLOT51 hr

Nearby

Winter Storm Watches in Illinois, 2021Every 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.