Alert archive / Illinois / Severe Thunderstorm Warnings in 2023

Severe Thunderstorm Warning 151, NWS Chicago, IL

July 28, 2023DeKalb County, Kane County, McHenry County, Illinois

NWS Chicago, IL issued this severe thunderstorm warning at Jul 28, 2023, 9:55 PM CDT for DeKalb County, Kane County, McHenry County, Illinois. It was in force for 50 min. No storm report in the archive falls inside the area while it was in force.

The area

The counties it named.

The facts

Issued: Jul 28, 2023, 9:55 PM CDT (02:55 UTC)
Expired: Jul 28, 2023, 10:45 PM CDT
In force: 50 min
Issued by: NWS Chicago, IL
Area: Storm-based polygon
Hail: 0.75 in
Wind: 60.0 mph

Counties DeKalb County, IL, Kane County, IL, McHenry County, IL

The radar

The Chicago radar (KLOT), 63 km from the middle of the area, began a volume at 02:57 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
Jul 28, 7:30 PM CDT	Severe Thunderstorm Watch	SPC	7 hr

The nearest sounding before it

Davenport, (KDVN), launched 00:00Z, 2.9 hours before the alert went out and 169 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: 3767 J/kg
Mixed-layer CIN: -61 J/kg
Mixed-layer LCL: 1322 m above ground
0-6 km bulk shear: 27 kt
0-1 km storm-relative helicity: 31 m²/s²
0-3 km storm-relative helicity: 64 m²/s²
Significant tornado parameter: 0.6
Supercell composite: 6.0

Open this sounding in Storm Lab

What forecasters said that day

The local office's own words before this severe thunderstorm 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 severe thunderstorm warning went out at Jul 28, 8:25 PM CDT, 1 hour 30 minutes earlier.

Area forecast discussion, Jul 28, 8:25 PM CDT, 1 hour 30 minutes before

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Hazardous weather outlook, Jul 28, 9:21 PM CDT, 34 minutes before

Hazardous Weather Outlook
National Weather Service Chicago/Romeoville IL
921 PM CDT Fri Jul 28 2023

ILZ003>006-008-010>013-019>021-023-032-033-039-103>108-INZ001-002-
010-011-019-300230-
Winnebago-Boone-McHenry-Lake IL-Ogle-Lee-De Kalb-Kane-DuPage-
La Salle-Kendall-Grundy-Kankakee-Livingston-Iroquois-Ford-
Northern Cook-Central Cook-Southern Cook-Northern Will-
Southern Will-Eastern Will-Lake IN-Porter-Newton-Jasper-Benton-
921 PM CDT Fri Jul 28 2023 /1021 PM EDT Fri Jul 28 2023/

This Hazardous Weather Outlook is for portions of North Central
Illinois...Northeast Illinois and Northwest Indiana.

.DAY ONE...Tonight.

Weather hazards expected...

  Significant Thunderstorm Risk...with an associated:
      Elevated Damaging Wind Risk...up to 70 mph.
      Limited Hail Risk...up to half dollar size.
      Limited Tornado Risk.
  Elevated Flooding Risk.

DISCUSSION...

Strong to severe thunderstorms will continue to overspread the
area late this evening into the early overnight hours, ahead of a
cold front which will move through the area late. Some of these
storms will be severe, capable of producing damaging to locally
destructive winds and large hail. A brief tornado or two can not
be ruled out. In addition, some of the storms will produce
torrential rainfall which could lead to flash flooding, especially
where several storms train across the same areas.

.DAYS TWO THROUGH SEVEN...Saturday through Thursday.

Saturday...
  Limited Thunderstorm Risk south of the Kankakee River.
  Moderate Swim Risk Lake Michigan Shore.
Thursday...
  Limited Thunderstorm Risk.

DISCUSSION...

Potentially hazardous swimming conditions may occur on Saturday
at Lake Michigan beaches.

.SPOTTER INFORMATION STATEMENT...

  Spotters may be needed through this evening.

GENERAL STORM MOTION OF THE DAY:

  Moving toward the east-southeast around 30 mph.

LMZ740>745-300230-
Winthrop Harbor to Wilmette Harbor IL-
Wilmette Harbor to Northerly Island IL-
Northerly Island to Calumet Harbor IL-
Calumet Harbor IL to Gary IN-Gary to Burns Harbor IN-
Burns Harbor to Michigan City IN-
921 PM CDT Fri Jul 28 2023

This Hazardous Weather Outlook is for portions of the Illinois
nearshore waters of Lake Michigan and the Indiana nearshore
waters of Lake Michigan.

.DAY ONE...Tonight.

Weather hazards expected...

  Significant Thunderstorm Risk...with an associated:
     Limited Hail Risk...up to half dollar size.
     Elevated Thunderstorm Wind Gust Risk...up to 60 knots.

.DAYS TWO THROUGH SEVEN...Saturday through Thursday.

Thursday...
  Limited Thunderstorm Risk.

Ratzer

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In the hours before

Special weather statement, Jul 28, 8:32 PM CDT, 1 hour 23 minutes before

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Special weather statement, Jul 28, 8:45 PM CDT, 1 hour 10 minutes before

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Special weather statement, Jul 28, 8:54 PM CDT, 1 hour 1 minute before

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Local storm report, Jul 28, 9:28 PM CDT, 27 minutes before

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Local storm report, Jul 28, 9:31 PM CDT, 24 minutes before

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Local storm report, Jul 28, 9:42 PM CDT, 13 minutes before

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The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 28, 7:25 PM CDT	Special Weather Statement	LOT	DuPage, Kane	35 min
Jul 28, 7:27 PM CDT	Severe Thunderstorm Warning	LOT	DuPage	33 min
Jul 28, 7:36 PM CDT	Flood Watch	LOT	Boone, Cook, DeKalb, DuPage, Grundy, Kane and 9 more	5 hr
Jul 28, 7:37 PM CDT	Severe Thunderstorm Warning	LOT	Cook, DuPage, Kane	38 min
Jul 28, 8:03 PM CDT	Areal Flood Advisory	LOT	DuPage, Kane	21 min
Jul 28, 8:10 PM CDT	Severe Thunderstorm Warning	LOT	Winnebago	50 min
Jul 28, 8:12 PM CDT	Severe Thunderstorm Warning	LOT	Cook, DuPage, Kane	48 min
Jul 28, 8:24 PM CDT	Flash Flood Warning	LOT	DuPage, Kane	4 hr
Jul 28, 8:30 PM CDT	Severe Thunderstorm Warning	LOT	DeKalb, Ogle, Winnebago	45 min
Jul 28, 8:32 PM CDT	Special Weather Statement	LOT	Lake	43 min
Jul 28, 8:41 PM CDT	Areal Flood Advisory	LOT	Boone, McHenry, Winnebago	4 hr
Jul 28, 8:45 PM CDT	Special Weather Statement	LOT	DuPage	45 min
Jul 28, 8:47 PM CDT	Areal Flood Advisory	LOT	Cook, Kane	4 hr
Jul 28, 8:54 PM CDT	Special Weather Statement	LOT	Cook, DuPage, Lake	66 min
Jul 28, 8:56 PM CDT	Severe Thunderstorm Warning	LOT	Winnebago	49 min
Jul 28, 9:01 PM CDT	Special Marine Warning	LOT		119 min
Jul 28, 9:04 PM CDT	Areal Flood Advisory	LOT	Lake	4 hr
Jul 28, 9:04 PM CDT	Severe Thunderstorm Warning	LOT	Lake	41 min
Jul 28, 9:16 PM CDT	Flash Flood Warning	LOT	Boone, Winnebago	3 hr
Jul 28, 9:17 PM CDT	Severe Thunderstorm Warning Considerable damage threat	LOT	Boone, McHenry	43 min
Jul 28, 9:28 PM CDT	Severe Thunderstorm Warning	LOT	DeKalb, Ogle, Winnebago	47 min
Jul 28, 9:41 PM CDT	Severe Thunderstorm Warning	LOT	Lee, Ogle	66 min
Jul 28, 9:47 PM CDT	Special Marine Warning	LOT		43 min
Jul 28, 10:03 PM CDT	Areal Flood Advisory	LOT	DeKalb	3 hr
Jul 28, 10:10 PM CDT	Severe Thunderstorm Warning Considerable damage threat	LOT	DeKalb, LaSalle	65 min
Jul 28, 10:23 PM CDT	Severe Thunderstorm Warning	LOT	Cook, DuPage, Kane	67 min
Jul 28, 10:26 PM CDT	Severe Thunderstorm Warning	LOT	Kendall	51 min
Jul 28, 10:28 PM CDT	Special Marine Warning	LOT		2 hr
Jul 28, 10:39 PM CDT	Severe Thunderstorm Warning	LOT	Grundy	50 min
Jul 28, 10:45 PM CDT	Severe Thunderstorm Warning Destructive damage threat	LOT	Kendall, Will	45 min
Jul 28, 10:55 PM CDT	Severe Thunderstorm Warning	LOT	Cook, Will	50 min
Jul 28, 11:01 PM CDT	Flash Flood Warning	LOT	Cook	108 min
Jul 28, 11:06 PM CDT	Severe Thunderstorm Warning	LOT	Kankakee	54 min
Jul 28, 11:11 PM CDT	Special Marine Warning	LOT		66 min
Jul 28, 11:24 PM CDT	Tornado Warning Tornado observed	LOT	Kankakee, Will	21 min
Jul 29, 12:26 AM CDT	Special Marine Warning	LOT		79 min
Jul 29, 3:25 AM CDT	Beach Hazards Statement	LOT	Cook, Lake	16 hr
Jul 29, 3:26 AM CDT	Small Craft Advisory	LOT		16 hr
Jul 28, 11:31 PM CDT	Severe Thunderstorm Warning Considerable damage threat	LOT	Lake, Newton	44 min
Jul 28, 11:43 PM CDT	Severe Thunderstorm Warning Considerable damage threat	LOT	Jasper, Porter	62 min

Nearby

Severe Thunderstorm Warnings in Illinois, 2023 Every severe thunderstorm warning in 2023

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.