187
FLUS43 KLOT 182008
HWOLOT

Hazardous Weather Outlook
National Weather Service Chicago/Romeoville IL
308 PM CDT Fri Sep 18 2026

ILZ003>006-008-010>013-019>021-023-032-033-039-103>108-INZ001-002-
010-011-019-192015-
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-
308 PM CDT Fri Sep 18 2026 /408 PM EDT Fri Sep 18 2026/

This Hazardous Weather Outlook is for portions of north central
Illinois...northeast Illinois and northwest Indiana.

.DAY ONE...Tonight.

Weather hazards expected...

  Elevated Thunderstorm Risk late.
  Elevated Flooding Risk late.
  High Swim Risk Lake Michigan Beaches.

DISCUSSION...

Thunderstorms with torrential rainfall are expected to shift
southward toward far northern Illinois overnight and to as far
south as the I-88 corridor by sunrise Saturday. Localized flash
flooding will be possible where heavy rains persist over the same
areas.

High waves will create dangerous swimming conditions at Lake
Michigan beaches in northeast Illinois tonight.

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

Saturday...
  Significant Flooding Risk.
  Elevated Thunderstorm Risk...with an associated:
     Level 1 of 5 Severe Thunderstorm Risk.
Sunday...
  Elevated Flooding Risk early.
  Limited Thunderstorm Risk.
Monday...
  Limited Flooding Risk.
  Limited Thunderstorm Risk.
Saturday through Tuesday...
  High Swim Risk Lake Michigan Beaches at times.

DISCUSSION...

Periods of heavy rain and scattered thunderstorms will continue
through at least Sunday morning and possibly into Monday.
Localized flash flooding and local river rises are possible. The
greatest threat for widespread areal flooding is Saturday into
Saturday night when multiple rounds of thunderstorms with
torrential rainfall cross the area.

Persistent northeast winds will maintain high waves and
dangerous swimming conditions at Lake Michigan beaches in
northeast Illinois and northwest Indiana through early next
week.

.SPOTTER INFORMATION STATEMENT...

  Spotter activation will not be necessary through tonight.

GENERAL STORM MOTION OF THE DAY:

 Moving toward the east-southeast at 20 mph.

$$

LMZ740>745-192015-
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-
308 PM CDT Fri Sep 18 2026

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...

  Hazardous conditions for small craft.
  Elevated Thunderstorm Risk late.

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

Saturday...
  Hazardous conditions for small craft are likely.
  Elevated Thunderstorm Risk...with an associated:
     Level 1 of 5 Severe Thunderstorm Risk.
Sunday and Monday...
  Hazardous conditions for small craft are likely.
  Limited Thunderstorm Risk.
Tuesday and Wednesday...
  Hazardous conditions for small craft are likely.

$$

Kluber

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