397
FLUS43 KLOT 182043
HWOLOT

Hazardous Weather Outlook
National Weather Service Chicago/Romeoville IL
343 PM CDT Mon Aug 18 2025

ILZ003>006-008-010>013-019>021-023-032-033-039-103>108-INZ001-002-
010-011-019-192045-
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-
343 PM CDT Mon Aug 18 2025 /443 PM EDT Mon Aug 18 2025/

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...with an associated:
     Level 2 of 5 Damaging Wind Risk...up to 70 mph.
     Level 1 of 5 Large Hail Risk...up to quarter size.
     Level 1 of 5 Tornado Risk.
  Significant Flooding Risk.
  Limited Excessive Heat Risk.

DISCUSSION...

Scattered thunderstorms will continue through this evening. Some
thunderstorms may be severe with damaging winds the primary
severe weather threat.

Very heavy rain is expected with these thunderstorms, which may
lead to localized flash flooding, especially in urban areas.

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

Tuesday...
  Limited Flooding Risk.
  Limited Thunderstorm Risk.

.SPOTTER INFORMATION STATEMENT...

Spotter reports will be needed through this evening.

GENERAL STORM MOTION OF THE DAY:

Moving toward the east at 20 to 25 mph.

$$

LMZ740>745-192045-
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-
343 PM CDT Mon Aug 18 2025

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...

  Elevated Thunderstorm Risk...with an associated:
     Level 2 of 5 Thunderstorm Wind Gust Risk...up to 50 knots.
     Level 1 of 5 Hail Risk...up to quarter size.

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

Tuesday...
  Hazardous conditions for small craft are likely.
  Limited Thunderstorm Risk.
Wednesday...
  Hazardous conditions for small craft are likely.

$$

Visit us at www.weather.gov/chicago