Alert archive / Illinois / Severe Thunderstorm Warnings in 2017

Severe Thunderstorm Warning 124, NWS Chicago, IL

July 19, 2017DeKalb County, LaSalle County, Lee County, Illinois

NWS Chicago, IL issued this severe thunderstorm warning at Jul 19, 2017, 8:30 PM CDT for DeKalb County, LaSalle County, Lee County, Illinois. It was in force for 30 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 19, 2017, 8:30 PM CDT (01:30 UTC)
Expired
Jul 19, 2017, 9:00 PM CDT
In force
30 min
Issued by
NWS Chicago, IL
Area
Storm-based polygon
Hail
1.0 in
Wind
60.0 mph

Counties DeKalb County, IL, LaSalle County, IL, Lee County, IL

The radar

The Chicago radar (KLOT), 75 km from the middle of the area, began a volume at 01:31 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.

IssuedProductOfficeLasted
Jul 19, 5:45 PM CDTSevere Thunderstorm WatchSPC6 hr

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 19, 6:48 PM CDT, 1 hour 42 minutes earlier.

Area forecast discussion, Jul 19, 6:48 PM CDT, 1 hour 42 minutes before
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Hazardous weather outlook, Jul 19, 3:48 PM CDT, 4 hours 42 minutes before
Hazardous Weather Outlook
National Weather Service Chicago/Romeoville IL
348 PM CDT Wed Jul 19 2017

ILZ003>006-008-010>014-019>023-032-033-039-INZ001-002-010-011-019-
202100-
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-
348 PM CDT Wed Jul 19 2017 /448 PM EDT Wed Jul 19 2017/

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

.DAY ONE...Tonight.

WEATHER HAZARDS EXPECTED:
  Elevated Thunderstorm Risk...with an associated:
     Limited Tornado Risk.
     Elevated Hail Risk...up to nickel size.
     Significant Thunderstorm Wind Damage Risk...up to 60 MPH.
  Elevated Flooding Risk.
  Elevated Excessive Heat Risk.

DISCUSSION:

Isolated to widely scattered thunderstorms have formed and are
mainly producing heavy rain. The strongest storms may produce
small hail or gusty winds. A second, larger complex of
thunderstorms is forecast to move southeast into far northern
Illinois overnight. It is still uncertain if the storms will move
through much of the area or just pass near the Illinois and
Wisconsin state line. There is potential to have severe winds with
this complex of storms, as well as periods of very heavy rainfall
that could bring localized flooding.

In addition...flooding is expected along portions of the Fox
and Des Plaines Rivers.

.DAYS TWO THROUGH SEVEN...Thursday through Tuesday.

Thursday...
  Limited Flooding Risk.
  Elevated Severe Thunderstorm Risk.
  Elevated Excessive Heat Risk.
Friday...
  Elevated Flooding Risk.
  Elevated Severe Thunderstorm Risk.
  Elevated Excessive Heat Risk.
Saturday...
  Limited Thunderstorm Risk.
  Elevated Excessive Heat Risk.
Sunday...
  Limited Thunderstorm Risk.
  High Swim Risk.
Tuesday...
  Limited Thunderstorm Risk.

DISCUSSION:

An active and humid weather pattern will continue into the
weekend. This will include periodic thunderstorm chances with
the potential for heavy rain that could result in flooding, and
possibly a severe thunderstorm threat. The humid air mass also
may lead to heat index readings in excess of 100 degrees, most
favored south of Interstate 80 Thursday through Saturday.

In addition, flooding will continue along portions of the Fox and
Des Plaines Rivers.

.SPOTTER INFORMATION STATEMENT...

Spotters may be needed tonight.

GENERAL STORM MOTION OF THE DAY:

Moving toward the southeast at 10 to 15 MPH.

&&

LMZ740>745-202100-
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-
348 PM CDT Wed Jul 19 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.

  Limited Thunderstorm Risk.

.DAYS TWO THROUGH SEVEN...Thursday through Tuesday.

Thursday and Friday...
  Elevated Thunderstorm Risk.
Saturday...
  Limited Thunderstorm Risk.
Sunday...
  Limited Thunderstorm Risk.
  Hazardous Conditions for Small Craft are likely.
Monday...
  Hazardous Conditions for Small Craft are likely.

&&

LMZ080-261-362-364-366-563-565-567-669-671-673-675-777-779-868-
870-872-874-876-878-202100-
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-
348 PM CDT Wed Jul 19 2017

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

.DAY ONE...Tonight.

Thunderstorms are likely tonight. Some of these overnight storms
may produce wind gusts in excess of 50 knots, especially for the
southern portions of the lake.

.DAYS TWO THROUGH SEVEN...Thursday through Tuesday.

There are periodic thunderstorm chances through Sunday.

&&

JEE

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The office that day

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

IssuedProductOfficeCountiesLasted
Jul 19, 7:21 PM CDTSevere Thunderstorm WarningLOTOgle, Winnebago54 min
Jul 19, 7:54 PM CDTSevere Thunderstorm WarningLOTBoone, DeKalb, Lee, McHenry, Ogle, Winnebago51 min
Jul 19, 8:05 PM CDTSpecial Marine WarningLOT25 min
Jul 19, 8:16 PM CDTTornado WarningLOTBoone, DeKalb, Ogle, Winnebago29 min
Jul 19, 8:24 PM CDTSpecial Marine WarningLOT2 hr
Jul 19, 8:34 PM CDTSevere Thunderstorm WarningLOTBoone, Cook, DeKalb, DuPage, Kane, Kendall and 4 more56 min
Jul 19, 9:08 PM CDTSevere Thunderstorm WarningLOTCook, DuPage, Grundy, Kendall, Will67 min
Jul 19, 9:55 PM CDTSpecial Weather StatementLOTKankakee35 min
Jul 19, 10:26 PM CDTSpecial Marine WarningLOT64 min
Jul 19, 10:37 PM CDTSpecial Weather StatementLOTFord, Iroquois53 min
Jul 19, 10:49 PM CDTSpecial Weather StatementLOTBoone, DeKalb, Kane, Lake, McHenry, Winnebago56 min
Jul 20, 3:28 AM CDTSpecial Weather StatementLOTBoone, Ogle, Winnebago47 min
Jul 20, 3:48 AM CDTSevere Thunderstorm WarningLOTBoone, DeKalb, Ogle, Winnebago42 min
Jul 20, 4:21 AM CDTSevere Thunderstorm WarningLOTBoone, DeKalb, Kane, Ogle39 min
Jul 20, 4:38 AM CDTSpecial Weather StatementLOTLee, Ogle52 min
Jul 20, 6:47 AM CDTSpecial Weather StatementLOTDeKalb, LaSalle, Lee43 min
Jul 20, 7:14 AM CDTAreal Flood AdvisoryLOTCook, DuPage, Kane, Kendall, Lake, Will2 hr
Jul 20, 7:21 AM CDTRiver Flood AdvisoryLOTWinnebago7 days
Jul 20, 7:21 AM CDTRiver Flood AdvisoryLOTOgle5 days
Jul 20, 7:21 AM CDTRiver Flood AdvisoryLOTLee66 hr
Jul 20, 7:27 AM CDTSpecial Weather StatementLOTGrundy, Kendall, LaSalle, Livingston48 min
Jul 20, 8:15 AM CDTRiver Flood WarningLOTCook5 days
Jul 20, 9:23 AM CDTRiver Flood WatchLOTWinnebago24 hr
Jul 20, 9:30 AM CDTRiver Flood AdvisoryLOTBoone4 days
Jul 20, 9:30 AM CDTRiver Flood AdvisoryLOTWinnebago52 hr
Jul 20, 9:30 AM CDTRiver Flood AdvisoryLOTWinnebago7 days
Jul 20, 9:30 AM CDTRiver Flood AdvisoryLOTWinnebago7 days
Jul 20, 2:15 PM CDTFlash Flood WatchLOTBoone, DeKalb, DuPage, Grundy, Kane, Kendall and 6 more42 hr
Jul 20, 2:51 PM CDTRiver Flood WarningLOTWinnebago6 days
Jul 20, 2:51 PM CDTRiver Flood WarningLOTWinnebago19 days

Nearby

Severe Thunderstorm Warnings in Illinois, 2017Every 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; radar from the NEXRAD Level II archive.