Alert archive / Illinois / Special Weather Statements in 2021

Special Weather Statement, NWS Chicago, IL

June 24, 2021Grundy County, Illinois

NWS Chicago, IL issued this special weather statement at Jun 24, 2021, 10:28 AM CDT for Grundy County, Illinois. It was in force for 17 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: Jun 24, 2021, 10:28 AM CDT (15:28 UTC)
Expired: Jun 24, 2021, 10:45 AM CDT
In force: 17 min
Issued by: NWS Chicago, IL

County Grundy County, IL

The radar

The Chicago radar (KLOT), 67 km from the middle of the area, began a volume at 15:29 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

Lincoln, IL (KILX), launched 12:00Z, 3.5 hours before the alert went out and 100 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: 1467 m above ground
0-6 km bulk shear: 28 kt
0-1 km storm-relative helicity: 176 m²/s²
0-3 km storm-relative helicity: 172 m²/s²
Significant tornado parameter: 0.0
Supercell composite: -0.3

Open this sounding in Storm Lab

The text

As transmitted.

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What forecasters said that day

The local office's own words before this special weather statement 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 special weather statement went out at Jun 24, 6:34 AM CDT, 3 hours 54 minutes earlier.

Area forecast discussion, Jun 24, 6:34 AM CDT, 3 hours 54 minutes before

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Hazardous weather outlook, Jun 24, 3:56 AM CDT, 6 hours 32 minutes before

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In the hours before

Special weather statement, Jun 24, 9:50 AM CDT, 38 minutes before

Special Weather Statement
National Weather Service Chicago/Romeoville
950 AM CDT Thu Jun 24 2021

ILZ032-241515-
Livingston IL-
950 AM CDT Thu Jun 24 2021

...SIGNIFICANT WEATHER ADVISORY FOR NORTHEASTERN LIVINGSTON COUNTY
UNTIL 1015 AM CDT...

At 950 AM CDT, Doppler radar was tracking a strong thunderstorm near
Odell, or near Dwight, moving northeast at 30 mph.

Penny size hail will be possible with this storm.

Locations impacted include...
Dwight, Odell, Campus, Reddick and Emington.

Including the following interstate...
 I-55 between mile markers 209 and 218.

LAT...LON 4104 8857 4111 8847 4111 8825 4097 8825
      4089 8847
TIME...MOT...LOC 1450Z 230DEG 25KT 4101 8846

Birk

Special weather statement, Jun 24, 10:28 AM CDT, 0 minutes before

Special Weather Statement
National Weather Service Chicago/Romeoville
1028 AM CDT Thu Jun 24 2021

ILZ021-023-032-039-107-241545-
Grundy IL-Livingston IL-Southern Will IL-Kankakee IL-Ford IL-
1028 AM CDT Thu Jun 24 2021

...SIGNIFICANT WEATHER ADVISORY FOR NORTHEASTERN LIVINGSTON...
SOUTHWESTERN WILL...SOUTHEASTERN GRUNDY...SOUTHWESTERN KANKAKEE AND
NORTH CENTRAL FORD COUNTIES UNTIL 1045 AM CDT...

At 1027 AM CDT, Doppler radar was tracking strong thunderstorms along
a line extending from near Gardner to 6 miles south of Braceville to
near Cullom. Movement was northeast at 20 mph.

Penny size hail and winds to 45 mph will be possible with these
storms.

Locations impacted include...
Braidwood, Wilmington, Herscher, Gardner, Lakewood Shores,
Braceville, Cullom, Saunemin, Essex, South Wilmington, Godley,
Buckingham, Cabery, Kempton, Campus, Reddick, Emington, East
Brooklyn, Stelle and Union Hill.

Including the following interstate...
 I-55 between mile markers 224 and 232.

LAT...LON 4079 8844 4120 8835 4134 8808 4118 8808
      4079 8817
TIME...MOT...LOC 1527Z 247DEG 17KT 4118 8826 4114 8824 4086 8830

Birk

The office that day

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

Issued	Product	Office	Counties	Lasted
Jun 24, 9:50 AM CDT	Special Weather Statement	LOT	Livingston	25 min
Jun 24, 11:43 AM CDT	Areal Flood Advisory	LOT	Ford, Grundy, Iroquois, Kankakee, Livingston, Will	4 hr
Jun 24, 2:19 PM CDT	Flash Flood Watch	LOT	Cook, DeKalb, DuPage, Ford, Grundy, Iroquois and 7 more	54 hr

Nearby

Special Weather Statements in Illinois, 2021 Every special weather statement 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.