Alert archive / Illinois / River Flood Advisories in 2021

River Flood Advisory 41, NWS Chicago, IL

October 30, 2021Grundy County, Illinois

NWS Chicago, IL issued this river flood advisory at Oct 30, 2021, 10:36 AM CDT for Grundy County, Illinois. It was in force for 10 hr.

The area

The counties it named.

The facts

Issued: Oct 30, 2021, 10:36 AM CDT (15:36 UTC)
Expired: Oct 30, 2021, 8:56 PM CDT
In force: 10 hr
Issued by: NWS Chicago, IL
Area: Storm-based polygon

County Grundy County, IL

The radar

The Chicago radar (KLOT), 45 km from the middle of the area, began a volume at 15:36 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 river

Written for the forecast point Mazon River near Coal City (COLI2). The gauge peaked at 10.11 ft at Oct 30, 2021, 3:00 PM CDT.

Action stage: 10 ft
Minor stage: 12 ft
Moderate stage: 16 ft
Major stage: 19 ft

This gauge today: stage, forecast and historic crests

Stage from the USGS instantaneous record for site 05542000, one reading an hour, from a day before the product to a day after it ended. Flood stages are today's.

What forecasters said that day

The local office's own words before this river flood advisory 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 river flood advisory went out at Oct 30, 6:40 AM CDT, 3 hours 56 minutes earlier.

Area forecast discussion, Oct 30, 6:40 AM CDT, 3 hours 56 minutes before

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Hazardous weather outlook, Oct 30, 3:02 AM CDT, 7 hours 34 minutes before

Hazardous Weather Outlook
National Weather Service Chicago/Romeoville IL
302 AM CDT Sat Oct 30 2021

ILZ003>006-008-010>013-019>021-023-032-033-039-103>108-INZ001-002-
010-011-019-310815-
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-
302 AM CDT Sat Oct 30 2021 /402 AM EDT Sat Oct 30 2021/

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

.DAY ONE...Today and Tonight.

  No hazardous weather is expected at this time.

.DAYS TWO THROUGH SEVEN...Sunday through Friday.

Sunday Night through Thursday night...
 Significant Freeze Risk.

DISCUSSION...

Each night Sunday night through Thursday night will feature
periods of subfreezing temperatures for outlying northern
Illinois.

.SPOTTER INFORMATION STATEMENT...

  Spotter activation will not be necessary through tonight.

LMZ740>745-310815-
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-
302 AM CDT Sat Oct 30 2021

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...Today and Tonight.

Weather hazards expected...

  Hazardous conditions for small craft.

.DAYS TWO THROUGH SEVEN...Sunday through Friday.

Sunday...
  Hazardous conditions for small craft are likely.

Kluber

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The office that day

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

Issued	Product	Office	Counties	Lasted
Oct 30, 1:50 AM CDT	River Flood Advisory	LOT	Grundy, LaSalle	49 hr
Oct 30, 6:23 AM CDT	River Flood Warning	LOT	LaSalle	26 hr
Oct 30, 11:24 AM CDT	River Flood Advisory	LOT	LaSalle	62 hr
Oct 30, 3:01 PM CDT	Small Craft Advisory	LOT		72 hr

Nearby

River Flood Advisories in Illinois, 2021 Every river flood advisory 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; radar from the NEXRAD Level II archive; the gauge from the NWS water service and the USGS.