Alert archive / Illinois / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 75, NWS Quad Cities, IA

August 10, 2021Stephenson County, Illinois

NWS Quad Cities, IA issued this severe thunderstorm warning at Aug 10, 2021, 6:16 PM CDT for Stephenson County, Illinois. It was in force for 13 min. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued: Aug 10, 2021, 6:16 PM CDT (23:16 UTC)
Expired: Aug 10, 2021, 6:29 PM CDT
In force: 13 min
Issued by: NWS Quad Cities, IA
Area: Storm-based polygon
Hail: 0.88 in
Wind: 60.0 mph

County Stephenson County, IL

The radar

The Milwaukee radar (KMKX), 100 km from the middle of the area, began a volume at 23:16 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 watch it was issued in

The SPC watch in force over the same counties when this warning went out.

Issued	Product	Office	Lasted
Aug 10, 3:47 PM CDT	Severe Thunderstorm Watch	SPC	6 hr

The nearest sounding before it

Davenport, (KDVN), launched 12:00Z, 11.3 hours before the alert went out and 119 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: 3755 J/kg
Mixed-layer CIN: -67 J/kg
Mixed-layer LCL: 819 m above ground
0-6 km bulk shear: 12 kt
0-1 km storm-relative helicity: -37 m²/s²
0-3 km storm-relative helicity: 4 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

538 
WUUS53 KDVN 102316
SVRDVN
ILC177-102345-
/O.NEW.KDVN.SV.W.0075.210810T2316Z-210810T2345Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Quad Cities IA/IL
616 PM CDT Tue Aug 10 2021

The National Weather Service in the Quad Cities has issued a

* Severe Thunderstorm Warning for...
  Eastern Stephenson County in northwestern Illinois...

* Until 645 PM CDT.

* At 616 PM CDT, a severe thunderstorm was located over Ridott, or 9
  miles east of Freeport, moving east at 35 mph.

  HAZARD...60 mph wind gusts and nickel size hail.

  SOURCE...Radar indicated.

  IMPACT...Expect damage to roofs, siding, and trees.

* This severe thunderstorm will remain over mainly rural areas of
  eastern Stephenson County, including the following locations...
  Albertus Airport, Rock Grove, Winneshiek, Dakota Dornink Airport,
  Afolkey and Lake Summerset.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

For your protection move to an interior room on the lowest floor of a
sturdy building.

&&

LAT...LON 4250 8940 4220 8940 4220 8960 4250 8959
TIME...MOT...LOC 2316Z 264DEG 31KT 4230 8945 

HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...0.88 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH

$$

Speck

1 follow-up statement

423 
WWUS53 KDVN 102329
SVSDVN

Severe Weather Statement
National Weather Service Quad Cities IA/IL
629 PM CDT Tue Aug 10 2021

ILC177-102339-
/O.CAN.KDVN.SV.W.0075.000000T0000Z-210810T2345Z/
Stephenson IL-
629 PM CDT Tue Aug 10 2021

...THE SEVERE THUNDERSTORM WARNING FOR EASTERN STEPHENSON COUNTY IS
CANCELLED...
        
The storm which prompted the warning has moved out of the area.
Therefore, the warning has been cancelled.

A Severe Thunderstorm Watch remains in effect until 1000 PM CDT for
northwestern Illinois.

LAT...LON 4250 8940 4220 8940 4220 8960 4250 8959
TIME...MOT...LOC 2326Z 264DEG 31KT 4231 8930 

$$

Speck

The office that day

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

Issued	Product	Office	Counties	Lasted
Aug 9, 7:12 PM CDT	Tornado Warning Tornado observed	DVN	Bureau	48 min
Aug 9, 7:30 PM CDT	Tornado Warning Tornado observed	DVN	Bureau	45 min
Aug 9, 8:02 PM CDT	Flash Flood Warning	DVN	Bureau	2 hr
Aug 9, 8:16 PM CDT	Severe Thunderstorm Warning	DVN	Bureau, Putnam	29 min
Aug 9, 9:39 PM CDT	Special Weather Statement	DVN	Henry	36 min
Aug 9, 9:54 PM CDT	Special Weather Statement	DVN	Henry	51 min
Aug 9, 10:44 PM CDT	Special Weather Statement	DVN	Mercer	31 min
Aug 10, 2:28 PM CDT	Heat Advisory	DVN	Bureau, Carroll, Hancock, Henderson, Henry, Jo Daviess and 7 more	29 hr
Aug 10, 4:04 PM CDT	Severe Thunderstorm Warning	DVN	Jo Daviess	56 min
Aug 10, 5:00 PM CDT	Severe Thunderstorm Warning	DVN	Carroll, Jo Daviess, Whiteside	45 min
Aug 10, 5:24 PM CDT	Severe Thunderstorm Warning	DVN	Carroll, Jo Daviess, Stephenson, Whiteside	51 min
Aug 10, 5:47 PM CDT	Special Weather Statement	DVN	Bureau	13 min
Aug 10, 5:47 PM CDT	Special Weather Statement	DVN	Bureau	13 min
Aug 10, 5:49 PM CDT	Severe Thunderstorm Warning	DVN	Stephenson	41 min
Aug 10, 6:50 PM CDT	Severe Thunderstorm Warning	DVN	Bureau	25 min
Aug 10, 6:53 PM CDT	Special Weather Statement	DVN	Mercer, Warren	37 min

Nearby

Severe Thunderstorm Warnings in Illinois, 2021 Every severe thunderstorm warning 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.