Beach Hazards Statement 9, NWS Chicago, IL

106 
WHUS43 KLOT 191651
CFWLOT

Coastal Hazard Message
National Weather Service Chicago IL
1151 AM CDT Tue Aug 19 2025

ILZ006-103-104-200100-
/O.CON.KLOT.BH.S.0009.250820T0100Z-250821T1500Z/
Lake IL-Northern Cook-Central Cook-
1151 AM CDT Tue Aug 19 2025

...BEACH HAZARDS STATEMENT REMAINS IN EFFECT FROM 8 PM CDT THIS
EVENING THROUGH THURSDAY MORNING...

* WHAT...High wave action and dangerous currents expected at 
  Lake Michigan beaches. Waves 3 to 6 feet expected.

* WHERE...Lake IL, Northern Cook and Central Cook Counties.

* WHEN...From this evening through Thursday morning.

* IMPACTS...Swimming conditions will be life threatening,
  especially for inexperienced swimmers. For information on swim
  advisories or bans at Chicago beaches: www. cpdbeaches. com.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Remain out of the water to avoid dangerous swimming conditions
and do not venture out onto piers, jetties, breakwalls, or other
shoreline structures.

&&

$$

INZ001-002-200100-
/O.CON.KLOT.BH.S.0009.250819T2100Z-250821T1500Z/
Lake IN-Porter-
1151 AM CDT Tue Aug 19 2025

...BEACH HAZARDS STATEMENT REMAINS IN EFFECT FROM 4 PM CDT THIS
AFTERNOON THROUGH THURSDAY MORNING...

* WHAT...High wave action and dangerous currents expected at 
  Lake Michigan beaches. Waves 3 to 6 feet expected.

* WHERE...Lake IN and Porter Counties.

* WHEN...From 4 PM CDT this afternoon through Thursday morning.

* IMPACTS...Swimming conditions will be life threatening, 
  especially for inexperienced swimmers.

* ADDITIONAL DETAILS...Increasing winds and building waves will 
  result in steadily deteriorating conditions late this 
  afternoon, with the worst swimming conditions expected after 
  sunset.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Remain out of the water to avoid dangerous swimming conditions
and do not venture out onto piers, jetties, breakwalls, or other
shoreline structures.

&&

$$

418 
WHUS43 KLOT 191846
CFWLOT

Coastal Hazard Message
National Weather Service Chicago IL
146 PM CDT Tue Aug 19 2025

INZ001-002-200300-
/O.EXT.KLOT.BH.S.0009.250819T1900Z-250821T1500Z/
Lake IN-Porter-
146 PM CDT Tue Aug 19 2025

...BEACH HAZARDS STATEMENT NOW IN EFFECT THROUGH THURSDAY
MORNING...

* WHAT...High wave action and dangerous currents expected at Lake
  Michigan beaches. Waves 3 to 6 ft expected.

* WHERE...Lake IN and Porter Counties.

* WHEN...Through Thursday morning.

* IMPACTS...Swimming conditions will be life threatening, 
  especially for inexperienced swimmers.

* ADDITIONAL DETAILS...The beach hazards statement is now in
  effect starting at 2 PM today. Conditions will continue to
  steadily deteriorate this afternoon and evening. 


PRECAUTIONARY/PREPAREDNESS ACTIONS...

Remain out of the water to avoid dangerous swimming conditions
and do not venture out onto piers, jetties, breakwalls, or other
shoreline structures.

&&

$$

ILZ006-103-104-200300-
/O.CON.KLOT.BH.S.0009.250820T0100Z-250821T1500Z/
Lake IL-Northern Cook-Central Cook-
146 PM CDT Tue Aug 19 2025

...BEACH HAZARDS STATEMENT REMAINS IN EFFECT FROM 8 PM CDT THIS
EVENING THROUGH THURSDAY MORNING...

* WHAT...High wave action and dangerous currents expected at Lake
  Michigan beaches. Waves 3 to 6 ft expected.

* WHERE...Lake IL, Northern Cook and Central Cook Counties.

* WHEN...From 8 PM CDT this evening through Thursday morning.

* IMPACTS...Swimming conditions will be life threatening, 
  especially for inexperienced swimmers. For information on swim 
  advisories or bans at Chicago beaches: www. cpdbeaches. com.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Remain out of the water to avoid dangerous swimming conditions
and do not venture out onto piers, jetties, breakwalls, or other
shoreline structures.

&&

$$

689 
WHUS43 KLOT 200125
CFWLOT

Coastal Hazard Message
National Weather Service Chicago IL
825 PM CDT Tue Aug 19 2025

ILZ006-103-104-200930-
/O.CON.KLOT.BH.S.0009.000000T0000Z-250821T1500Z/
Lake IL-Northern Cook-Central Cook-
825 PM CDT Tue Aug 19 2025

...BEACH HAZARDS STATEMENT REMAINS IN EFFECT THROUGH THURSDAY
MORNING...

* WHAT...High wave action and dangerous currents expected at 
  Lake Michigan beaches. Waves 3 to 6 ft expected.

* WHERE...Lake IL, Northern Cook and Central Cook Counties.

* WHEN...From 8 PM CDT this evening through Thursday morning.

* IMPACTS...Swimming conditions will be life threatening, 
  especially for inexperienced swimmers. For information on swim 
  advisories or bans at Chicago beaches: www. cpdbeaches. com.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Remain out of the water to avoid dangerous swimming conditions
and do not venture out onto piers, jetties, breakwalls, or other
shoreline structures.

&&

$$

INZ001-002-200930-
/O.CON.KLOT.BH.S.0009.000000T0000Z-250821T1500Z/
Lake IN-Porter-
825 PM CDT Tue Aug 19 2025

...BEACH HAZARDS STATEMENT REMAINS IN EFFECT THROUGH THURSDAY
MORNING...

* WHAT...High wave action and dangerous currents expected at 
  Lake Michigan beaches. Waves 3 to 6 ft expected.

* WHERE...Lake IN and Porter Counties.

* WHEN...Through Thursday morning.

* IMPACTS...Swimming conditions will be life threatening, 
  especially for inexperienced swimmers.

* ADDITIONAL DETAILS...The beach hazards statement is now in 
  effect starting at 2 PM today. Conditions will continue to 
  steadily deteriorate this afternoon and evening.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Remain out of the water to avoid dangerous swimming conditions
and do not venture out onto piers, jetties, breakwalls, or other
shoreline structures.

&&

$$

782 
WHUS43 KLOT 200126 CCA
CFWLOT

Coastal Hazard Message...CORRECTED
National Weather Service Chicago IL
826 PM CDT Tue Aug 19 2025

ILZ006-103-104-200930-
/O.COR.KLOT.BH.S.0009.000000T0000Z-250821T1500Z/
Lake IL-Northern Cook-Central Cook-
826 PM CDT Tue Aug 19 2025

...BEACH HAZARDS STATEMENT REMAINS IN EFFECT THROUGH THURSDAY
MORNING...

* WHAT...High wave action and dangerous currents expected at 
  Lake Michigan beaches. Waves 3 to 6 ft expected.

* WHERE...Lake IL, Northern Cook and Central Cook Counties.

* WHEN...Through Thursday morning.

* IMPACTS...Swimming conditions will be life threatening, 
  especially for inexperienced swimmers. For information on swim 
  advisories or bans at Chicago beaches: www. cpdbeaches. com.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Remain out of the water to avoid dangerous swimming conditions
and do not venture out onto piers, jetties, breakwalls, or other
shoreline structures.

&&

$$

INZ001-002-200930-
/O.CON.KLOT.BH.S.0009.000000T0000Z-250821T1500Z/
Lake IN-Porter-
826 PM CDT Tue Aug 19 2025

...BEACH HAZARDS STATEMENT REMAINS IN EFFECT THROUGH THURSDAY
MORNING...

* WHAT...High wave action and dangerous currents expected at 
  Lake Michigan beaches. Waves 3 to 6 ft expected.

* WHERE...Lake IN and Porter Counties.

* WHEN...Through Thursday morning.

* IMPACTS...Swimming conditions will be life threatening, 
  especially for inexperienced swimmers.

* ADDITIONAL DETAILS...The beach hazards statement is now in 
  effect starting at 2 PM today. Conditions will continue to 
  steadily deteriorate this afternoon and evening.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Remain out of the water to avoid dangerous swimming conditions
and do not venture out onto piers, jetties, breakwalls, or other
shoreline structures.

&&

$$

400 
WHUS43 KLOT 200804
CFWLOT

Coastal Hazard Message
National Weather Service Chicago IL
304 AM CDT Wed Aug 20 2025

ILZ006-103-104-201615-
/O.CON.KLOT.BH.S.0009.000000T0000Z-250821T1500Z/
Lake IL-Northern Cook-Central Cook-
304 AM CDT Wed Aug 20 2025

...BEACH HAZARDS STATEMENT REMAINS IN EFFECT THROUGH THURSDAY
MORNING...

* WHAT...High wave action and dangerous currents expected at Lake
  Michigan beaches. Waves 3 to 6 feet expected.

* WHERE...Lake IL, Northern Cook and Central Cook Counties.

* WHEN...Through Thursday morning.

* IMPACTS...Swimming conditions will be life threatening, 
  especially for inexperienced swimmers. For information on swim 
  advisories or bans at Chicago beaches: www. cpdbeaches. com.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Remain out of the water to avoid dangerous swimming conditions
and do not venture out onto piers, jetties, breakwalls, or other
shoreline structures.

&&

$$

INZ001-002-201615-
/O.CON.KLOT.BH.S.0009.000000T0000Z-250821T1500Z/
Lake IN-Porter-
304 AM CDT Wed Aug 20 2025

...BEACH HAZARDS STATEMENT REMAINS IN EFFECT THROUGH THURSDAY
MORNING...

* WHAT...High wave action and dangerous currents expected at Lake
  Michigan beaches. Waves 3 to 6 feet occurring.

* WHERE...Lake IN and Porter Counties.

* WHEN...Through Thursday morning.

* IMPACTS...Swimming conditions will be life threatening,
  especially for inexperienced swimmers.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Remain out of the water to avoid dangerous swimming conditions
and do not venture out onto piers, jetties, breakwalls, or other
shoreline structures.

&&

$$

466 
WHUS43 KLOT 201547
CFWLOT

Coastal Hazard Message
National Weather Service Chicago IL
1047 AM CDT Wed Aug 20 2025

ILZ006-103-104-210000-
/O.CON.KLOT.BH.S.0009.000000T0000Z-250821T1500Z/
Lake IL-Northern Cook-Central Cook-
1047 AM CDT Wed Aug 20 2025

...BEACH HAZARDS STATEMENT REMAINS IN EFFECT THROUGH THURSDAY
MORNING...

* WHAT...High wave action and dangerous currents expected at Lake
  Michigan beaches. Waves 3 to 6 feet occurring.

* WHERE...Lake IL, Northern Cook and Central Cook Counties.

* WHEN...Through Thursday morning.

* IMPACTS...Swimming conditions will be life threatening, 
  especially for inexperienced swimmers. For information on swim 
  advisories or bans at Chicago beaches: www. cpdbeaches. com.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Remain out of the water to avoid dangerous swimming conditions
and do not venture out onto piers, jetties, breakwalls, or other
shoreline structures.

&&

$$

INZ001-002-210000-
/O.CON.KLOT.BH.S.0009.000000T0000Z-250821T1500Z/
Lake IN-Porter-
1047 AM CDT Wed Aug 20 2025

...BEACH HAZARDS STATEMENT REMAINS IN EFFECT THROUGH THURSDAY
MORNING...

* WHAT...High wave action and dangerous currents expected at 
  Lake Michigan beaches. Waves 3 to 6 feet occurring.

* WHERE...Lake IN and Porter Counties.

* WHEN...Through Thursday morning.

* IMPACTS...Swimming conditions will be life threatening, 
  especially for inexperienced swimmers.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Remain out of the water to avoid dangerous swimming conditions
and do not venture out onto piers, jetties, breakwalls, or other
shoreline structures.

&&

$$

975 
WHUS43 KLOT 202001
CFWLOT

Coastal Hazard Message
National Weather Service Chicago IL
301 PM CDT Wed Aug 20 2025

ILZ006-103-104-210415-
/O.CON.KLOT.BH.S.0009.000000T0000Z-250821T1500Z/
Lake IL-Northern Cook-Central Cook-
301 PM CDT Wed Aug 20 2025

...BEACH HAZARDS STATEMENT REMAINS IN EFFECT THROUGH THURSDAY
MORNING...

* WHAT...High wave action and dangerous currents expected at 
  Lake Michigan beaches. Waves 3 to 6 feet occurring.

* WHERE...Lake IL, Northern Cook and Central Cook Counties.

* WHEN...Through Thursday morning.

* IMPACTS...Swimming conditions will be life threatening, 
  especially for inexperienced swimmers. For information on swim 
  advisories or bans at Chicago beaches: www. cpdbeaches. com.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Remain out of the water to avoid dangerous swimming conditions
and do not venture out onto piers, jetties, breakwalls, or other
shoreline structures.

&&

$$

INZ001-002-210415-
/O.CON.KLOT.BH.S.0009.000000T0000Z-250821T1500Z/
Lake IN-Porter-
301 PM CDT Wed Aug 20 2025

...BEACH HAZARDS STATEMENT REMAINS IN EFFECT THROUGH THURSDAY
MORNING...

* WHAT...High wave action and dangerous currents expected at 
  Lake Michigan beaches. Waves 3 to 6 feet occurring.

* WHERE...Lake IN and Porter Counties.

* WHEN...Through Thursday morning.

* IMPACTS...Swimming conditions will be life threatening, 
  especially for inexperienced swimmers.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Remain out of the water to avoid dangerous swimming conditions
and do not venture out onto piers, jetties, breakwalls, or other
shoreline structures.

&&

$$

026 
WHUS43 KLOT 210228
CFWLOT

Coastal Hazard Message
National Weather Service Chicago IL
928 PM CDT Wed Aug 20 2025

ILZ006-103-104-211030-
/O.CON.KLOT.BH.S.0009.000000T0000Z-250821T1500Z/
Lake IL-Northern Cook-Central Cook-
928 PM CDT Wed Aug 20 2025

...BEACH HAZARDS STATEMENT REMAINS IN EFFECT THROUGH THURSDAY
MORNING...

* WHAT...High wave action and dangerous currents expected at Lake
  Michigan beaches. Waves 3 to 6 ft occurring.

* WHERE...Lake IL, Northern Cook and Central Cook Counties.

* WHEN...Through Thursday morning.

* IMPACTS...Swimming conditions will be life threatening, 
  especially for inexperienced swimmers. For information on swim 
  advisories or bans at Chicago beaches: www. cpdbeaches. com.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Remain out of the water to avoid dangerous swimming conditions
and do not venture out onto piers, jetties, breakwalls, or other
shoreline structures.

&&

$$

INZ001-002-211030-
/O.CON.KLOT.BH.S.0009.000000T0000Z-250821T1500Z/
Lake IN-Porter-
928 PM CDT Wed Aug 20 2025

...BEACH HAZARDS STATEMENT REMAINS IN EFFECT THROUGH THURSDAY
MORNING...

* WHAT...High wave action and dangerous currents expected at Lake
  Michigan beaches. Waves 3 to 6 ft occurring.

* WHERE...Lake IN and Porter Counties.

* WHEN...Through Thursday morning.

* IMPACTS...Swimming conditions will be life threatening, 
  especially for inexperienced swimmers.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Remain out of the water to avoid dangerous swimming conditions
and do not venture out onto piers, jetties, breakwalls, or other
shoreline structures.

&&

$$

880 
WHUS43 KLOT 210822
CFWLOT

Coastal Hazard Message
National Weather Service Chicago IL
322 AM CDT Thu Aug 21 2025

ILZ006-103-104-211630-
/O.EXT.KLOT.BH.S.0009.000000T0000Z-250821T1800Z/
Lake IL-Northern Cook-Central Cook-
322 AM CDT Thu Aug 21 2025

...BEACH HAZARDS STATEMENT NOW IN EFFECT UNTIL 1 PM CDT THIS
AFTERNOON...

* WHAT...High wave action of 3 to 5 ft and dangerous currents at
  Lake Michigan beaches occurring. 

* WHERE...Lake IL, Northern Cook and Central Cook Counties.

* WHEN...Until 1 PM CDT this afternoon.

* IMPACTS...Swimming conditions will be life threatening, 
  especially for inexperienced swimmers. For information on swim 
  advisories or bans at Chicago beaches: www. cpdbeaches. com.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Remain out of the water to avoid dangerous swimming conditions
and do not venture out onto piers, jetties, breakwalls, or other
shoreline structures.

&&

$$

INZ001-002-211630-
/O.EXT.KLOT.BH.S.0009.000000T0000Z-250821T1800Z/
Lake IN-Porter-
322 AM CDT Thu Aug 21 2025

...BEACH HAZARDS STATEMENT NOW IN EFFECT UNTIL 1 PM CDT THIS
AFTERNOON...

* WHAT...High wave action of 3 to 5 ft and dangerous currents at
  Lake Michigan beaches occurring. 

* WHERE...Lake IN and Porter Counties.

* WHEN...Until 1 PM CDT this afternoon.

* IMPACTS...Swimming conditions will be life threatening, 
  especially for inexperienced swimmers.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Remain out of the water to avoid dangerous swimming conditions
and do not venture out onto piers, jetties, breakwalls, or other
shoreline structures.

&&

$$

116 
WHUS43 KLOT 211456
CFWLOT

Coastal Hazard Message
National Weather Service Chicago IL
956 AM CDT Thu Aug 21 2025

ILZ006-103-104-211800-
/O.CON.KLOT.BH.S.0009.000000T0000Z-250821T1800Z/
Lake IL-Northern Cook-Central Cook-
956 AM CDT Thu Aug 21 2025

...BEACH HAZARDS STATEMENT REMAINS IN EFFECT UNTIL 1 PM CDT THIS
AFTERNOON...

* WHAT...High wave action of 3 to 5 ft and dangerous currents at 
  Lake Michigan beaches occurring.

* WHERE...Lake IL, Northern Cook and Central Cook Counties.

* WHEN...Until 1 PM CDT this afternoon.

* IMPACTS...Swimming conditions will be life threatening, 
  especially for inexperienced swimmers. For information on swim 
  advisories or bans at Chicago beaches: www. cpdbeaches. com.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Remain out of the water to avoid dangerous swimming conditions
and do not venture out onto piers, jetties, breakwalls, or other
shoreline structures.

&&

$$

INZ001-002-211800-
/O.CON.KLOT.BH.S.0009.000000T0000Z-250821T1800Z/
Lake IN-Porter-
956 AM CDT Thu Aug 21 2025

...BEACH HAZARDS STATEMENT REMAINS IN EFFECT UNTIL 1 PM CDT THIS
AFTERNOON...

* WHAT...High wave action of 3 to 5 ft and dangerous currents at 
  Lake Michigan beaches occurring.

* WHERE...Lake IN and Porter Counties.

* WHEN...Until 1 PM CDT this afternoon.

* IMPACTS...Swimming conditions will be life threatening, 
  especially for inexperienced swimmers.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Remain out of the water to avoid dangerous swimming conditions
and do not venture out onto piers, jetties, breakwalls, or other
shoreline structures.

&&

$$

380 
WHUS43 KLOT 211755
CFWLOT

Coastal Hazard Message
National Weather Service Chicago IL
1255 PM CDT Thu Aug 21 2025

ILZ006-103-104-211900-
/O.EXP.KLOT.BH.S.0009.000000T0000Z-250821T1800Z/
Lake IL-Northern Cook-Central Cook-
1255 PM CDT Thu Aug 21 2025

...BEACH HAZARDS STATEMENT WILL EXPIRE AT 1 PM CDT THIS
AFTERNOON...

Waves and rip currents will continue to subside this afternoon
thus the Beach Hazard will be allowed to expire. Though, a
moderate swim risk will persist through this evening. 

$$

INZ001-002-211900-
/O.EXP.KLOT.BH.S.0009.000000T0000Z-250821T1800Z/
Lake IN-Porter-
1255 PM CDT Thu Aug 21 2025

...BEACH HAZARDS STATEMENT WILL EXPIRE AT 1 PM CDT THIS
AFTERNOON...

Waves and rip currents will continue to subside this afternoon
thus the Beach Hazard will be allowed to expire. Though, a
moderate swim risk will persist through this evening.

$$

Area Forecast Discussion
National Weather Service Chicago/Romeoville, IL
340 AM CDT Tue Aug 19 2025

.KEY MESSAGES...

- The long awaited pattern change to quieter and drier is on our
  doorstep and will persist through early next week, along with
  noticeably less humid conditions Wednesday onward.

- Temperatures early to mid next week will likely be an early
  Fall preview!

- Dangerous swimming conditions will develop at southern Lake
  Michigan beaches late this afternoon into this evening and
  persist into Thursday morning.

&&

.DISCUSSION...
Issued at 340 AM CDT Tue Aug 19 2025

Today through Thursday Night:

The convectively augmented synoptic short-wave that has kept the
"parade of storms" going near/south of I-88 early this morning
is peeling off to the east. A primarily dry and cooler day,
albeit with humidity levels still on the uncomfortable side
(especially I-80 and south), is on the way today.

With the footprint of deep convection much less than earlier and
expected to diminish into the morning, we went ahead and
canceled the areal Flood Watch that was in effect. Please refer
to any flood warning or advisory products that remain in effect
for your area. In the near-term through about 8-9am this morning,
we'll have to keep an eye on the possible development of patchy
fog across portions of interior far northern Illinois.

A cold front will move south across the area this morning,
clearing our far southern CWA locales by early afternoon. The
combination of the environment being thoroughly worked over and
cloud cover should limit the potential for the redevelopment of
any thunderstorms after any activity lingering past sunrise this
morning comes to an end. Held onto a slight chance of storms in
closer proximity to the front (ie. near/south of US-24) to be
safe through about 2-3pm CDT.

More notably, the front will shift winds to brisk northerly down
the full fetch of Lake Michigan, with speeds peaking tonight
through Wednesday. This will result in large waves and strong
currents at the beaches, with Beach Hazards Statements hoisted
this morning (earliest start late this afternoon for northwest
Indiana).

Tonight into Wednesday morning will be mostly dry with the
possible small exception of downwind of Lake Michigan, as 850 mb
temps down into the lower teens Celsius generate some modest
lake induced instability. Inversion heights look too marginal
for any bonafide showers, but can't rule out some spotty
lake effect sprinkles into portions of northeast Illinois and
northwest Indiana. Highs on Wednesday will be in the upper 70s
to lower 80s inland, and mid 70s near the lake. Following a
seasonably cool Wednesday night (upper 50s to lower 60s well
inland of the lake) as skies clear out, Thursday will be one of
the nicest days in quite some time for the area. Expect mostly
sunny skies, much more comfortable humidity levels, and highs
similar to those of Wednesday. Thursday night will be similarly
comfortably cool outside of Chicago to Wednesday night.

Friday through Monday:

Friday will feature a brief warm-up back to the lower-mid 80s
away from the lake ahead of the next approaching cold front.
This front will come through at an unfavorable time Friday night
with much less moisture to work with, so expect a dry fro-pa for
most of the area. Saturday will be near to slightly below
seasonable with comfortable humidity levels. Seasonably deep
mid-uper troughing will set up over from Ontario to Hudson Bay
Sunday through early next work week. 850 mb temps below +10C
through this time will set the stage for highs in the lower to
mid 70s, dew points in the 40s and 50s, and overnight lows in
the upper 40s to lower 50s outside of Chicago! The below normal
temperatures should persist through mid next week before
returning back to near or above seasonal norms heading into
Labor Day Weekend.

Castro

&&

.AVIATION /06Z TAFS THROUGH 12Z WEDNESDAY/...
Issued at 1250 AM CDT Tue Aug 19 2025

Forecast concerns include...

Scattered thunderstorms early this morning.
Ifr, possible lifr cigs through mid morning.
Fog potential around sunrise.
Wind shift to northerly Tuesday morning.

Scattered thunderstorms have redeveloped over the Chicago
terminals and will continue for the next few hours, slowly
moving east. Isolated thunderstorms will remain possible
through daybreak ahead of a cold front that will move across the
area. Confidence is low for possible coverage with any
additional convection in the predawn hours and near daybreak.
Prob thunder mention still seems reasonable at this time.

Prevailing winds will start light southerly but are expected to
shift south/southwest over the next few hours then to the west/
southwest prior to daybreak. As the cold front moves across the
area, winds will shift northwest and then are expected to become
mainly northerly, with speeds potentially into the 10-15kt
range. Eventually, winds will become north/northeast for ORD/MDW
and only medium confidence for this timing. Winds will likely
become north/northeast at MDW before ORD and trends will need to
be monitored.

Patches of lifr cigs began to develop a few hours ago, prior to
this latest round of thunderstorms. Guidance is in very good
agreement with low clouds developing ahead of the cold front and
then slowly lifting Tuesday morning. Prevailing ifr cigs seem on
track based on current model trends, which will then lift
through mvfr and likely scatter out late Tuesday afternoon or
Tuesday evening.

Fog is also possible around daybreak, most likely northwest of
the Chicago terminals and may be brief, associated with the cold
front. Confidence for fog is low, but trends suggest ifr vis at
RFD/DPA and have included tempo mention with this forecast.
There is a small chance that dense fog may develop but that
seems unlikely, if widespread ifr cigs develop. cms

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...Flood Watch until 4 AM CDT early this morning for ILZ003-
     ILZ004-ILZ005-ILZ006-ILZ008-ILZ010-ILZ011-ILZ012-ILZ013-
     ILZ019-ILZ020-ILZ021-ILZ023-ILZ103-ILZ104-ILZ105-ILZ106-
     ILZ107-ILZ108.

IN...Flood Watch until 4 AM CDT early this morning for INZ001-
     INZ002.

LM...None.

&&

Visit us at weather.gov/chicago

Hazardous Weather Outlook...UPDATED
National Weather Service Chicago/Romeoville IL
936 PM CDT Mon Aug 18 2025

ILZ003>006-008-010>013-019>021-023-032-033-039-103>108-INZ001-002-
010-011-019-200245-
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-
936 PM CDT Mon Aug 18 2025 /1036 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 1 of 5 Damaging Wind Risk...up to 60 mph.
  Elevated Flooding Risk.

DISCUSSION...

Scattered thunderstorms will continue tonight, mainly along and
south of Interstate 80, where an isolated strong to severe
thunderstorm is possible.

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

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

Tuesday...
  Limited Flooding Risk.
  Limited Thunderstorm Risk.
Wednesday...
  High Swim Risk at Lake Michigan Beaches.

.SPOTTER INFORMATION STATEMENT...

Spotter reports of flooding will be appreciated.

GENERAL STORM MOTION OF THE DAY:

Moving toward the east at 20 to 30 mph.

LMZ740>745-200245-
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-
936 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 1 of 5 Thunderstorm Wind Gust Risk...up to 40 knots.

.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

Preliminary Local Storm Report
National Weather Service Chicago IL
1212 AM CDT Tue Aug 19 2025

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

1211 AM     Rain             2 ENE Ingalls Park      41.54N 88.00W
08/19/2025  M1.08 Inch       Will               IL   Mesonet

            1.08 inches of rain in 15 minutes. Personal
            weather station KILNEWLE66.

&&

Special Weather Statement
National Weather Service Chicago/Romeoville
1215 AM CDT Tue Aug 19 2025

ILZ105-190530-
Southern Cook IL-
1215 AM CDT Tue Aug 19 2025

...STRONG THUNDERSTORMS WILL IMPACT SOUTHEASTERN COOK COUNTY THROUGH
1230 AM CDT...

At 1215 AM CDT, Doppler radar was tracking strong thunderstorms along
a line extending from Crestwood to near Frankfort Square. Movement
was east at 30 mph.

HAZARD...Wind gusts up to 50 mph.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects.

Strong thunderstorms will be near...
  Homewood, Park Forest, Dixmoor, Riverdale, Blue Island, Richton
  Park, Chicago Heights, Crestwood, Hazel Crest, and Tinley Park
  around 1220 AM CDT.

Other locations impacted by these storms include East Hazel Crest,
Robbins, South Chicago Heights, Calumet Park, and West Pullman.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

&&

LAT...LON 4149 8762 4148 8779 4156 8779 4166 8777
      4166 8775 4165 8773 4165 8768 4166 8765
      4166 8762 4164 8762 4164 8759
TIME...MOT...LOC 0515Z 266DEG 25KT 4165 8775 4149 8779

MAX HAIL SIZE...0.00 IN
MAX WIND GUST...50 MPH

Izzi

Special Weather Statement
National Weather Service Chicago/Romeoville
1230 AM CDT Tue Aug 19 2025

ILZ104>106-108-190600-
Eastern Will IL-Southern Cook IL-Central Cook IL-Northern Will IL-
1230 AM CDT Tue Aug 19 2025

...STRONG THUNDERSTORMS WILL IMPACT EAST CENTRAL WILL AND
SOUTHEASTERN COOK COUNTIES THROUGH 100 AM CDT...

At 1229 AM CDT, Doppler radar was tracking strong thunderstorms along
a line extending from Merrionette Park to near Manhattan. Movement
was east at 25 mph.

HAZARD...Wind gusts up to 50 mph.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects.

Strong thunderstorms will be near...
  Homewood, Park Forest, Dixmoor, Riverdale, Blue Island, Richton
  Park, Alsip, Crestwood, Hazel Crest, and Tinley Park around 1235
  AM CDT.
  Chicago Heights, Calumet City, Thornton, and Glenwood around 1240
  AM CDT.
  Hammond and Lansing around 1245 AM CDT.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

Frequent cloud to ground lightning is occurring with these storms.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.

&&

LAT...LON 4141 8753 4141 8790 4143 8790 4171 8772
      4175 8753 4174 8754 4174 8752 4173 8752
TIME...MOT...LOC 0529Z 263DEG 20KT 4168 8769 4143 8789

MAX HAIL SIZE...0.00 IN
MAX WIND GUST...50 MPH

Izzi

Preliminary Local Storm Report
National Weather Service Chicago IL
139 AM CDT Tue Aug 19 2025

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

1244 AM     Flash Flood      2 S Orland Hills        41.57N 87.84W
08/19/2025                   Cook               IL   Public

            Several reports from from mPING of flooded
            streets.

&&

Preliminary Local Storm Report
National Weather Service Chicago IL
140 AM CDT Tue Aug 19 2025

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0900 PM     Rain             2 E Rockton             42.45N 89.04W
08/18/2025  M3.54 Inch       Winnebago          IL   Public

            Total rainfall for the day.

&&

Preliminary Local Storm Report
National Weather Service Chicago IL
220 AM CDT Tue Aug 19 2025

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0145 AM     Flood            1 WSW Hammond           41.58N 87.52W
08/19/2025                   Lake               IN   Public

            The Little Calumet River at Munster crested
            at 12.3 feet, 0.3 above flood stage.

&&