Hazard Report Provided By forecast.weather.gov

Hazardous Weather Outlook
National Weather Service Chicago/Romeoville IL
416 AM CDT Mon Jul 27 2026

ILZ003>006-008-010>013-019>021-023-032-033-039-103>108-INZ001-002-
010-011-019-280930-
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-
416 AM CDT Mon Jul 27 2026 /516 AM EDT Mon Jul 27 2026/

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

.DAY ONE...Today and Tonight.

Weather hazards expected...

 Elevated Thunderstorm Risk...with an associated:
     Level 3 of 5 Damaging Wind Risk...locally over 70 mph.
     Level 2 of 5 Large Hail Risk...up to golf ball size.
     Level 1 of 5 Tornado Risk.
  Limited Flooding Risk.
  Elevated to Significant Excessive Heat Risk.
  High Swim Risk Lake Michigan Beaches late tonight.

DISCUSSION...

There is a chance of thunderstorms today into the early evening
hours. If storm occur, they could be severe, capable of
destructive winds locally over 70 mph and hail to the size of golf
balls. Any storms that form today will also produce torrential
rainfall.

Outside of any storms, stifling humidity will combine with hot
temperatures to produce dangerous heat indices between 100 and 115
degrees. The highest heat indices are expected near the I-39
corridor.

Large waves and dangerous currents are expected at unprotected
Lake Michigan beaches late tonight.

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

Tuesday through Wednesday morning...
  High Swim Risk Lake Michigan Beaches.
Thursday...
  Limited Thunderstorm Risk.
Friday...
  Elevated Flooding Risk.
  Limited Thunderstorm Risk.
Saturday and Sunday...
  Limited Thunderstorm Risk.

DISCUSSION...

Thunderstorms are possible Monday morning, some of which may
produce locally damaging wind gusts and large hail.

An additional round of thunderstorms may occur late Monday
afternoon into the evening. Any storms that do develop would
likely become severe and be capable of producing damaging winds
and large hail.

In areas not affected by storms or cloudiness from storms, peak
heat indices of 100 to 110 degrees are possible Monday afternoon.

.SPOTTER INFORMATION STATEMENT...

  Spotters may be needed today into this evening.

GENERAL STORM MOTION OF THE DAY:

  Moving toward the southeast at 30 mph.

$$

URGENT - WEATHER MESSAGE
National Weather Service Chicago IL
302 AM CDT Mon Jul 27 2026

ILZ003-008-010-011-019-021-032-271815-
/O.NEW.KLOT.FG.Y.0011.260727T0802Z-260727T1300Z/
/O.CON.KLOT.XH.W.0002.000000T0000Z-260728T0200Z/
Winnebago-Ogle-Lee-De Kalb-La Salle-Grundy-Livingston-
Including the cities of Fairbury, Dixon, Sycamore, Ottawa, Coal
City, Morris, Byron, Pontiac, Streator, Dwight, Oregon, Mendota,
Marseilles, La Salle, DeKalb, Rochelle, Minooka, and Rockford
302 AM CDT Mon Jul 27 2026

...EXTREME HEAT WARNING REMAINS IN EFFECT UNTIL 9 PM CDT THIS
EVENING...
...DENSE FOG ADVISORY IN EFFECT UNTIL 8 AM CDT THIS MORNING...

* WHAT...For the Extreme Heat Warning, dangerously hot conditions
  with peak heat index values 110 to locally over 115 degrees
  expected. For the Dense Fog Advisory, visibility less than one
  quarter mile in dense fog.

* WHERE...Livingston, De Kalb, La Salle, Lee, Ogle, Winnebago, and
  Grundy Counties.

* WHEN...For the Extreme Heat Warning, until 9 PM CDT this evening.
  For the Dense Fog Advisory, until 8 AM CDT this morning.

* IMPACTS...Heat related illnesses increase significantly during
  extreme heat and high humidity events. Low visibility could make
  driving conditions hazardous.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Drink plenty of fluids, stay in an air-conditioned room, stay out of
the sun, and check up on relatives and neighbors.

If driving, slow down, use your headlights, and leave plenty of
distance ahead of you.

&&

$$

URGENT - WEATHER MESSAGE
National Weather Service Chicago IL
302 AM CDT Mon Jul 27 2026

ILZ003-008-010-011-019-021-032-271815-
/O.NEW.KLOT.FG.Y.0011.260727T0802Z-260727T1300Z/
/O.CON.KLOT.XH.W.0002.000000T0000Z-260728T0200Z/
Winnebago-Ogle-Lee-De Kalb-La Salle-Grundy-Livingston-
Including the cities of Fairbury, Dixon, Sycamore, Ottawa, Coal
City, Morris, Byron, Pontiac, Streator, Dwight, Oregon, Mendota,
Marseilles, La Salle, DeKalb, Rochelle, Minooka, and Rockford
302 AM CDT Mon Jul 27 2026

...EXTREME HEAT WARNING REMAINS IN EFFECT UNTIL 9 PM CDT THIS
EVENING...
...DENSE FOG ADVISORY IN EFFECT UNTIL 8 AM CDT THIS MORNING...

* WHAT...For the Extreme Heat Warning, dangerously hot conditions
  with peak heat index values 110 to locally over 115 degrees
  expected. For the Dense Fog Advisory, visibility less than one
  quarter mile in dense fog.

* WHERE...Livingston, De Kalb, La Salle, Lee, Ogle, Winnebago, and
  Grundy Counties.

* WHEN...For the Extreme Heat Warning, until 9 PM CDT this evening.
  For the Dense Fog Advisory, until 8 AM CDT this morning.

* IMPACTS...Heat related illnesses increase significantly during
  extreme heat and high humidity events. Low visibility could make
  driving conditions hazardous.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Drink plenty of fluids, stay in an air-conditioned room, stay out of
the sun, and check up on relatives and neighbors.

If driving, slow down, use your headlights, and leave plenty of
distance ahead of you.

&&

$$

Hazard Report Provided By forecast.weather.gov