Alert archive / Illinois / Severe Thunderstorm Warnings in 2017

Severe Thunderstorm Warning 38, NWS Chicago, IL

April 10, 2017Lake County, McHenry County, Illinois

NWS Chicago, IL issued this severe thunderstorm warning at Apr 10, 2017, 4:18 PM CDT for Lake County, McHenry County, Illinois. It was in force for 42 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: Apr 10, 2017, 4:18 PM CDT (21:18 UTC)
Expired: Apr 10, 2017, 5:00 PM CDT
In force: 42 min
Issued by: NWS Chicago, IL
Area: Storm-based polygon
Hail: 1.0 in
Wind: 60.0 mph

Counties Lake County, IL, McHenry County, IL

The radar

The Milwaukee radar (KMKX), 77 km from the middle of the area, began a volume at 21:17 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
Apr 10, 1:48 PM CDT	Severe Thunderstorm Watch	SPC	8 hr

The nearest sounding before it

Davenport, (KDVN), launched 12:00Z, 9.3 hours before the alert went out and 209 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: 2257 m above ground
0-6 km bulk shear: 61 kt
0-1 km storm-relative helicity: 95 m²/s²
0-3 km storm-relative helicity: 194 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 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 Apr 10, 2:59 PM CDT, 1 hour 19 minutes earlier.

Area forecast discussion, Apr 10, 2:59 PM CDT, 1 hour 19 minutes before

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Hazardous weather outlook, Apr 10, 2:56 PM CDT, 1 hour 22 minutes before

Hazardous Weather Outlook
National Weather Service Chicago/Romeoville IL
256 PM CDT Mon Apr 10 2017

ILZ003>006-008-010>014-019>023-032-033-039-INZ001-002-010-011-019-
112000-
Winnebago-Boone-McHenry-Lake Illinois-Ogle-Lee-De Kalb-Kane-
DuPage-Cook-La Salle-Kendall-Grundy-Will-Kankakee-Livingston-
Iroquois-Ford-Lake Indiana-Porter-Newton-Jasper-Benton-
256 PM CDT Mon Apr 10 2017 /356 PM EDT Mon Apr 10 2017/

THIS HAZARDOUS WEATHER OUTLOOK IS FOR NORTH CENTRAL ILLINOIS...
NORTHEAST ILLINOIS AND NORTHWEST INDIANA.

.DAY ONE...Tonight.

WEATHER HAZARDS EXPECTED:
  Significant Thunderstorm Risk...with an associated:
      Limited Tornado Risk.
      Elevated Hail Risk...up to 2 inches size.
      Elevated Thunderstorm Wind Damage Risk...up to 65 MPH.
  Limited Non Thunderstorm Wind Risk.

DISCUSSION:

Additional strong to severe thunderstorms will continue
across portions of northern Illinois through the afternoon. These storms
will develop in a significantly more unstable environment and will pose a
more substantial severe threat with time including large hail of up to 2
inches in diameter and damaging wind gusts to 65 mph. While there is a chance
of a tornado or two, the threat is on the lower side.
These storms will move east across the Chicago and Kankakee areas
through the afternoon, and into northwest Indiana by
very late afternoon or early evening. The storms may develop into a fast
moving cluster. Storms should exit the area to the east after 8 or 9 pm CDT.

.DAYS TWO THROUGH SEVEN...Tuesday through Sunday.

Friday through Sunday...
  Limited Thunderstorm Risk.

.SPOTTER INFORMATION STATEMENT...

Spotters will likely be needed this afternoon and early evening.

GENERAL STORM MOTION OF THE DAY:

Moving to the northeast at 45 mph.

&&

LMZ740>745-112000-
Winthrop Harbor to Wilmette Harbor-
Wilmette Harbor to Northerly Island-
Northerly Island to Calumet Harbor-Calumet Harbor to Gary-
Gary to Burns Harbor-Burns Harbor to Michigan City-
256 PM CDT Mon Apr 10 2017

THIS HAZARDOUS WEATHER OUTLOOK IS FOR THE illinois NEARSHORE
WATERS OF LAKE MICHIGAN AND THE indiana NEARSHORE WATERS OF LAKE
MICHIGAN.

.DAY ONE...Tonight.

Hazardous Conditions for Small Craft are likely.

.DAYS TWO THROUGH SEVEN...Tuesday through Sunday.

Tuesday through Thursday...
  No Hazards.

Friday and Saturday...
  Hazardous Conditions for Small Craft are likely.

&&

LMZ080-261-362-364-366-563-565-567-669-671-673-675-777-779-868-
870-872-874-876-878-112000-
Lake Michigan from Michigan City IN to St. Joseph MI 5 NM
offshore to Mid Lake-
Lake Michigan from Seul Choix Point to Rock Island Passage 5 NM
offshore to Mid Lake-
Lake Michigan South of a line from Seul Choix Point to the
Mackinac Bridge and north of a line from Charlevoix MI to South
Fox Island 5 NM offshore-
Lake Michigan from Charlevoix to Point Betsie MI 5 NM offshore to
Mid Lake-
Lake Michigan from Point Betsie to Manistee MI 5 NM offshore to
Mid Lake-
Lake Michigan from Rock Island Passage to Sturgeon Bay WI-
Lake Michigan from Sturgeon Bay to Two Rivers WI 5 NM offshore to
Mid Lake-
Lake Michigan from Two Rivers to Sheboygan WI 5 NM offshore to
Mid Lake-
Lake Michigan from Sheboygan to Port Washington WI 5 NM offshore
to Mid Lake-
Lake Michigan from Port Washington to North Point Light WI 5 NM
offshore to Mid Lake-
Lake Michigan from North Point Light to Wind Point WI 5 NM
offshore to Mid Lake-
Lake Michigan from Wind Point WI to Winthrop Harbor IL 5 NM
offshore to Mid Lake-
Lake Michigan from Winthrop Harbor to Wilmette Harbor IL 5 NM
offshore to Mid Lake-
Lake Michigan from Wilmette Harbor IL to Michigan City IN 5 NM
offshore to Mid Lake-
Lake Michigan from Pentwater to Manistee MI 5 NM offshore to Mid
Lake-
Lake Michigan from Whitehall to Pentwater MI 5 NM offshore to Mid
Lake-
Lake Michigan from Grand Haven to Whitehall MI 5 NM offshore to
Mid Lake-
Lake Michigan from Holland to Grand Haven MI 5 NM offshore to Mid
Lake-
Lake Michigan from South Haven to Holland MI 5 NM offshore to Mid
Lake-
Lake Michigan from St. Joseph to South Haven MI 5 NM offshore to
Mid Lake-
256 PM CDT Mon Apr 10 2017

THIS HAZARDOUS WEATHER OUTLOOK IS FOR THE OPEN WATERS OF LAKE
MICHIGAN.

.DAY ONE...Tonight.

Thunderstorms are likely through this evening.

.DAYS TWO THROUGH SEVEN...Tuesday through Sunday.

There is a chance of thunderstorms Friday night through early
Sunday.

&&

KMD

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In the hours before

Local storm report, Apr 10, 3:05 PM CDT, 1 hour 13 minutes before

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Local storm report, Apr 10, 3:11 PM CDT, 1 hour 7 minutes before

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Local storm report, Apr 10, 3:13 PM CDT, 1 hour 5 minutes before

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Local storm report, Apr 10, 3:18 PM CDT, 1 hour before

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Local storm report, Apr 10, 3:19 PM CDT, 59 minutes before

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Local storm report, Apr 10, 3:22 PM CDT, 56 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
Apr 10, 4:38 AM CDT	Special Weather Statement	LOT	McHenry	22 min
Apr 10, 4:47 AM CDT	Special Weather Statement	LOT	DuPage, Kane	43 min
Apr 10, 5:07 AM CDT	Special Marine Warning	LOT		83 min
Apr 10, 5:20 AM CDT	Special Weather Statement	LOT	LaSalle	40 min
Apr 10, 6:55 AM CDT	Special Weather Statement	LOT	Iroquois	50 min
Apr 10, 12:26 PM CDT	Special Weather Statement	LOT	Grundy, Kendall, LaSalle, Will	49 min
Apr 10, 12:49 PM CDT	Severe Thunderstorm Warning	LOT	Cook, Kendall, Will	41 min
Apr 10, 1:10 PM CDT	Severe Thunderstorm Warning	LOT	Cook	29 min
Apr 10, 1:12 PM CDT	Special Marine Warning	LOT		93 min
Apr 10, 2:08 PM CDT	Special Weather Statement	LOT	Cook, DuPage, Kane, Kendall	52 min
Apr 10, 2:55 PM CDT	Special Weather Statement	LOT	Boone, DeKalb, Lake, Lee, McHenry, Ogle and 1 more	50 min
Apr 10, 4:14 PM CDT	Severe Thunderstorm Warning	LOT	Livingston	61 min
Apr 10, 4:24 PM CDT	Special Marine Warning	LOT		2 hr
Apr 10, 5:54 PM CDT	Special Weather Statement	LOT	Lake	51 min
Apr 10, 8:01 AM CDT	Special Weather Statement	LOT	Benton	29 min
Apr 10, 6:01 PM CDT	Special Weather Statement	LOT	Newton	29 min

Nearby

Severe Thunderstorm Warnings in Illinois, 2017 Every severe thunderstorm warning in 2017

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.