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Current Conditions

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Current Local Radar

Temperature
90°F
Feels Like:
95°F
Dew Point	Humidity
69°F	50%

Mostly Cloudy

Wind Strength
Light	Moderate	Strong
South at 9 mph

Local Graphical Forecast (Updated: 08/15/25 4:12 pm)

Friday (8/15)
Day	Night

	50%
High	Low
	74

Saturday (8/16)
Day	Night

40%	30%
High	Low
92	73

Sunday (8/17)
Day	Night

20%	20%
High	Low
90	72

Monday (8/18)
Day	Night

40%	50%
High	Low
91	73

Tuesday (8/19)
Day	Night


High	Low
86	68

Wednesday (8/20)
Day	Night


High	Low
78	65

Thursday (8/21)
Day	Night


High	Low
82	64

Detailed Text Forecast (Updated: 08/15/25 4:12 pm)

Friday Night: A 50 percent chance of showers and thunderstorms, mainly after midnight. Increasing clouds, with a low around 74. South wind around 5 mph.

Saturday: A 40 percent chance of showers and thunderstorms, mainly after 1pm. Partly sunny, with a high near 92. Heat index values as high as 98. West southwest wind 5 to 10 mph.

Saturday Night: A 30 percent chance of showers and thunderstorms. Partly cloudy, with a low around 73. West wind 5 to 10 mph becoming south in the evening.

Sunday: A 20 percent chance of showers and thunderstorms. Partly sunny, with a high near 90. Heat index values as high as 97. East northeast wind 5 to 10 mph.

Sunday Night: A 20 percent chance of showers and thunderstorms after 1am. Partly cloudy, with a low around 72. East northeast wind 5 to 10 mph.

Monday: A 40 percent chance of showers and thunderstorms. Mostly sunny, with a high near 91.

Monday Night: A 50 percent chance of showers and thunderstorms. Mostly cloudy, with a low around 73.

Tuesday: A chance of showers and thunderstorms. Mostly sunny, with a high near 86.

Tuesday Night: Mostly cloudy, with a low around 68.

Wednesday: Mostly sunny, with a high near 78.

Wednesday Night: Mostly clear, with a low around 65.

Thursday: Sunny, with a high near 82.

Thursday Night: Mostly clear, with a low around 64.

Friday: Sunny, with a high near 84.

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SPC Convective Outlook Day 1

See Product Description

635
ACUS01 KWNS 151958
SWODY1
SPC AC 151957

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0257 PM CDT Fri Aug 15 2025

Valid 152000Z - 161200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THOUGH TONIGHT
FROM THE UPPER MISSISSIPPI VALLEY INTO SOUTH DAKOTA...

...SUMMARY...
Scattered strong to severe storms with damaging winds and large hail
are likely through tonight from the Upper Mississippi Valley into
South Dakota.

...Upper MS Valley through tonight...
Convection is ongoing in a cluster across north central IA, with
clear evidence of cold pool development and a bowing structure. The
storms will likely continue to spread eastward/southeastward through
the afternoon while encountering a very unstable environment
characterized by surface temperatures in the upper 80s and
boundary-layer dewpoints in the low-mid 70s. Cluster is expected to
be maintained given deep-layer shear vectors near 30 kt (oriented
west-northwest to east-southeast), and steep midlevel lapse rates
will support the potential for occasional damaging/severe outflow
gusts and isolated large hail with the strongest embedded updrafts.

Otherwise, a strengthening low-level warm advection regime will
develop tonight into MN along a slow-moving front, and atop the cold
pool from the ongoing IA storms. Elevated buoyancy will remain
large, with the potential to support additional severe storm
development with occasional large hail and damaging/severe outflow
gusts.

...NE/SD this evening into tonight...
High-based convection is expected to form this afternoon from
southeast WY into the western NE Panhandle and southwest SD. The
initial storms will be capable of producing a few severe outflow
gusts in an environment with deep inverted-V profiles and modest
buoyancy. Though surface convective inhibition will increase this
evening with diurnal cooling, storms could grow into a cluster
through outflow interactions, while moving into richer low-level
moisture and larger buoyancy with eastward extent (along and south
of a baroclinic zone across SD).

..Thompson.. 08/15/2025

.PREV DISCUSSION... /ISSUED 1130 AM CDT Fri Aug 15 2025/

...MN/IA/WI...
Recent satellite imagery shows a pair of convectively generated
vorticity maxima moving across the northern/central Plains, with the
northernmost vorticity max over the eastern ND/SD border and the
southernmost vorticity max over north-central NE. Showers and
thunderstorms have persisted near these features over the last
several hours, but the strongest cells in both of these clusters
have recently shown a weakening trend. A moist and buoyant airmass,
characterized by dewpoints in the upper 60s/low 70s, exists
downstream and redevelopment is possible ahead of both of these
vorticity maxima. How that redevelopment evolves is uncertain, with
recent guidance offering varied solutions regarding overall coverage
and evolution.

Redevelopment appears most probable with the southern vorticity
maxima, given the ample moist and buoyancy that exists downstream.
This development should grow upscale quickly, with the resulting
convective cluster then tracking southeastward. Recent guidance
continues to trend farther south, so the wind probabilities were
extended southward to cover this potential. Damaging gusts appear
like the most likely threat through the evening. Current progression
of the northern vorticity maximum takes it into a less buoyant
airmass across central MN and northern WI, and redevelopment
along/ahead of this disturbance appears less likely.

Depending on the strength of the IA cluster, additional development
is possible in its wake amid a strengthening low-level jet and
associated warm-air advection over its outflow. Steep mid-level
lapse rates should still be in place, supporting strong updrafts and
large hail with these elevated storms.

Lastly, a decaying convective line may reach the southwestern
MN/northwestern IA vicinity late in the period. Given the potential
for preceding storms, the amount of buoyancy that will still be in
place remains is uncertain. However, if thunderstorm coverage is low
or most storms develop farther east, enough buoyancy could remain to
support strong updrafts capable of damaging gusts and/or hail within
the convective line or any preceding more cellular storms.

..NE/SD this afternoon through tonight...
Strong heating and ample mid-level moisture will result in scattered
high-based thunderstorm development across eastern WY and western
NE/SD by late afternoon. Isolated hail and strong gusts are possible
with this initial activity. This activity will then track
east-northeastward through the early evening into a progressively
more moist and unstable air mass across NE and SD. The combination
of improving thermodynamic environment and an intensifying nocturnal
low-level jet will likely aid in thunderstorm intensification and
upscale growth through the evening across northern NE and central
SD. Guidance continues to vary significantly with the strength of
this MCS, but general consensus would suggest the threat for strong
to severe gusts will persist across SD tonight. There is at least a
low probability for the development of a well-organized MCS that
could produce significant severe gusts. However, that probability is
currently too low to introduce an unconditional sig wind area.

...TX Coastal Plain into the Hill Country and Southeast TX...
A maturing tropical disturbance is near south TX, with associated
outflow currently spreading northward across the TX Coastal Plain.
Limited lightning has been noted with in the short-lived cores that
have been developing along this outflow. This process of brief
intensification along this outflow is expected throughout the day,
with an overall increase in thunderstorm coverage anticipated. A
modest increase in low to mid-level flow is expected along the
eastern periphery of this system, spreading northward into central
and southeast TX. Even so, shear will remain weak, with a
disorganized multicellular pulse storm mode anticipated. Given the
very moist profiles (i.e. PW values over 2"), a few water-loaded
downbursts are possible, but should be isolated enough to preclude
the need for severe probabilities.

$$

The "Convective Outlooks" issued by SPC can be thought of as a detailed discussion of the Severe Thunderstorm threat and it's associated risks nationwide. Risk levels range from Marginal to Slight, Enhanced, Moderate, and High and are issued based on the likelihood of 3 major severe weather threats; the risk of tornadoes, damaging winds, and hail. These discussions are often heavily laced meteorological terminology that may be difficult to understand without a background in the field. However understanding these discussions shouldn't be thought of as necessary. Instead, should DuPage county fall under one of these threat levels for severe weather, the response should be to have a heightened level of awareness about the deveoloping weather. Keep an eye on the "Watch County Notification" for any active severe weather watches issued for DuPage county; the "Hazardous Weather Outlook" and "Severe Weather Statement" can also be helpful in explaining the developing risk; additionally, watch for "Active Weather Warnings" and keep an eye on our "Regional Satellite and Radar" products which can be viewed with active watches/warnings or lightning activity.

Hazardous Weather Outlook

See Product Description

076
FLUS43 KLOT 152039
HWOLOT

Hazardous Weather Outlook
National Weather Service Chicago/Romeoville IL
339 PM CDT Fri Aug 15 2025

ILZ003>006-008-010>013-019>021-023-032-033-039-103>108-INZ001-002-
010-011-019-162045-
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-
339 PM CDT Fri Aug 15 2025 /439 PM EDT Fri Aug 15 2025/

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

.DAY ONE...Tonight.

Weather hazards expected...

Limited Thunderstorm Risk...with an associated:
Level 1 of 5 Damaging Wind Risk...up to 60 mph.
Limited Flooding Risk.

DISCUSSION...

Scattered thunderstorms are expected tonight, mainly north of
I-80. The strongest storms could produce locally damaging winds up
to 60 mph and torrential rainfall which could result in a
localized flash flood threat.

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

Saturday and Sunday...
Limited Thunderstorm Risk...with an associated:
Level 1 of 5 Severe Thunderstorm Risk.
Limited Flooding Risk.
Limited to Elevated Excessive Heat Risk.
Monday and Tuesday...
Limited Thunderstorm Risk.
Limited Flooding Risk.
Limited Excessive Heat Risk.

DISCUSSION...

There will be periodic chances of thunderstorms Saturday through
Tuesday with a limited risk for severe thunderstorms and heavy
rainfall induced localized flash flooding.

Afternoon heat indices above 100 degrees are possible as well
Saturday through Tuesday near and south of I-80.

.SPOTTER INFORMATION STATEMENT...

Spotters may be needed this evening.

GENERAL STORM MOTION OF THE DAY:

Moving toward the east at 40 mph.

$$

LMZ740>745-162045-
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-
339 PM CDT Fri Aug 15 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...

Limited Thunderstorm Risk...with an associated:
Level 1 of 5 Thunderstorm Wind Gust Risk...up to 50 kt.

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

Saturday and Sunday...
Limited Thunderstorm Risk...with an associated:
Level 1 of 5 Severe Thunderstorm Risk.
Monday and Tuesday...
Limited Thunderstorm Risk.

$$

- Izzi

Visit us at www.weather.gov/chicago

The "Hazardous Weather Outlook" contains information regarding any and all weather expected to occur within the region that could be hazardous to travel, life or property. This is one of our most highly recommended products to check on a daily basis, and it some cases multiple times per day should significant weather be expected to affect DuPage county.

SPC Convective Outlook Day 2

See Product Description

987
ACUS02 KWNS 151736
SWODY2
SPC AC 151735

Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1235 PM CDT Fri Aug 15 2025

Valid 161200Z - 171200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR MUCH OF SOUTH
DAKOTA...

...SUMMARY...
Scattered severe thunderstorms are possible Saturday over South
Dakota primarily during the late afternoon through the late evening
period. Large hail and severe gusts appear to be the primary
hazards with the stronger storms.

...Northern Great Plains...
A mid-level ridge centered over the lower MS Valley/Mid South will
feature a weak disturbance moving from the WY/CO vicinity into the
Dakotas Saturday night. A residual composite front will remain
draped east-west from the Upper Midwest into western SD, where it
will intersect a lee trough from the central High Plains
north-northwestward into eastern MT. Although large-scale ascent
will remain fairly weak across the region, isolated thunderstorms
will likely develop in the vicinity of the lee trough and Black
Hills by the late afternoon as convective inhibition erodes. To the
north of the front, a moist and unstable airmass featuring a
moderate to very unstable boundary layer will develop by mid-late
afternoon. Model guidance shows a gradual increase in storm
coverage during the early evening over western/central SD. Ample
directional shear will support effective shear magnitudes 30-40 kt
and storm organization with the stronger storms. Large hail and
severe gusts appear to be the primary threats.

...Midwest...
A linear cluster of thunderstorms is expected to be ongoing Saturday
morning across parts of the Upper MS Valley/western Great Lakes.
Model guidance differs on the evolution of this potentia
shower/thunderstorm activity, but west-northwesterly mid-level flow
poleward of a mid-level anticyclone centered over the lower MS
Valley, will potentially favor some continuation of storms
downstream across the southwestern Great Lakes. Models continue to
show a moist/unstable airmass across southern portions of the Great
Lakes. Although large-scale ascent will remain weak across the
region, regenerative storm development on remnant outflow may yield
a subsequent evolution of a storm cluster but uncertainty remains
high. Isolated damaging gusts/hail are the main threats with these
storms.

..Smith.. 08/15/2025

$$

The "Convective Outlooks" issued by SPC can be thought of as a detailed discussion of the Severe Thunderstorm threat and it's associated risks nationwide. Risk levels range from Marginal to Slight, Enhanced, Moderate, and High and are issued based on the likelihood of 3 major severe weather threats; the risk of tornadoes, damaging winds, and hail. These discussions are often heavily laced meteorological terminology that may be difficult to understand without a background in the field. However understanding these discussions shouldn't be thought of as necessary. Instead, should DuPage county fall under one of these threat levels for severe weather, the response should be to have a heightened level of awareness about the deveoloping weather. Keep an eye on the "Watch County Notification" for any active severe weather watches issued for DuPage county; the "Hazardous Weather Outlook" and "Severe Weather Statement" can also be helpful in explaining the developing risk; additionally, watch for "Active Weather Warnings" and keep an eye on our "Regional Satellite and Radar" products which can be viewed with active watches/warnings or lightning activity.

SPC Convective Outlook Day 3

See Product Description

807
ACUS03 KWNS 151928
SWODY3
SPC AC 151927

Day 3 Convective Outlook
NWS Storm Prediction Center Norman OK
0227 PM CDT Fri Aug 15 2025

Valid 171200Z - 181200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM MONTANA
THROUGH THE UPPER MIDWEST AND SOUTHERN GREAT LAKES...

...SUMMARY...
Thunderstorms with potential for isolated severe wind gusts and hail
will be possible on Sunday across parts of the northern Plains
eastward into Upper Midwest and southern Great Lakes.

...Northern Plains/Upper Midwest into the southern Great Lakes...
A flattened mid-level ridge will influence thunderstorm activity on
Sunday across a large part of the CONUS. On the northern periphery
of the ridge, a weak mid-level disturbance is forecast to crest the
ridge over the north-central states and move from SD to the western
Great Lakes. Warm 700-mb temperatures and an associated capping
inversion will likely limit storm development across the lower MO
Valley. A composite surface boundary, likely modulated by previous
day's thunderstorm outflow, is forecast to be draped from the
southern Great Lakes west-northwestward into parts of the Upper
Midwest and into portions of the northern High Plains.

Showers and storms may be ongoing early Sunday morning across the
Upper Midwest in association with weak low-level warm advection in
advance of the aforementioned impulse. Isolated to scattered
diurnal storms are forecast to focus along the low-level boundary
during the afternoon/evening given large-scale upper forcing for
ascent will remain weak to negligible. Despite expected strong
diurnal destabilization, deep-layer shear will likely remain modest
and limit storm organization potential, with isolated severe gusts
and large hail being the severe hazards.

..Smith.. 08/15/2025

$$

The "Convective Outlooks" issued by SPC can be thought of as a detailed discussion of the Severe Thunderstorm threat and it's associated risks nationwide. Risk levels range from Marginal to Slight, Enhanced, Moderate, and High and are issued based on the likelihood of 3 major severe weather threats; the risk of tornadoes, damaging winds, and hail. These discussions are often heavily laced meteorological terminology that may be difficult to understand without a background in the field. However understanding these discussions shouldn't be thought of as necessary. Instead, should DuPage county fall under one of these threat levels for severe weather, the response should be to have a heightened level of awareness about the deveoloping weather. Keep an eye on the "Watch County Notification" for any active severe weather watches issued for DuPage county; the "Hazardous Weather Outlook" and "Severe Weather Statement" can also be helpful in explaining the developing risk; additionally, watch for "Active Weather Warnings" and keep an eye on our "Regional Satellite and Radar" products which can be viewed with active watches/warnings or lightning activity.