799
FLUS43 KLOT 181621
HWOLOT

Hazardous Weather Outlook
National Weather Service Chicago/Romeoville IL
1121 AM CDT Mon Aug 18 2025

ILZ003>006-008-010>013-019>021-023-032-033-039-103>108-INZ001-002-
010-011-019-191630-
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-
1121 AM CDT Mon Aug 18 2025 /1221 PM EDT Mon Aug 18 2025/

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

.DAY ONE...This Afternoon and Tonight.

Weather hazards expected...

  Elevated Thunderstorm Risk...with an associated:
     Level 2 of 5 Damaging Wind Risk...up to 60 mph.
     Level 1 of 5 Tornado Risk
  Elevated Flooding Risk...level 2 out of 4.
  Limited Excessive Heat Risk.
  High Swim Risk at Lake Michigan Beaches through Mid Afternoon.

DISCUSSION...

High waves and dangerous currents are expected at Lake Michigan
beaches through mid-afternoon, especially for Lake County and
northern Cook County.

Hot and humid conditions are expected today with peak afternoon
heat indices near or just above 100 degrees away from Lake
Michigan.

Showers and storms are expected this afternoon and evening. A few
may be severe with damaging winds and torrential downpours. With
saturated soil conditions, even a brief period of intense rainfall
could lead to a flash flooding situation.

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

Tuesday...
  Limited Thunderstorm Risk, mainly southeast of I-55.

.SPOTTER INFORMATION STATEMENT...

  Spotters may be needed this afternoon and evening.

GENERAL STORM MOTION OF THE DAY:

  Moving toward the east at 25 mph.

$$

LMZ740>745-191630-
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-
1121 AM 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...This Afternoon and Tonight.

Weather hazards expected...

  Hazardous conditions for small craft.
  Elevated Thunderstorm Risk...with an associated:
     Level 1 of 5 Thunderstorm Wind Gust Risk...up to 50 kts.

.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.

$$

Lenning

Visit us at www.weather.gov/chicago