Essentials:

Regional Satellite and Radar...

-with Watches and Warnings
-with Lightning Detection

Helpful Information:

Weather Safety:

Current Conditions

A message from COD Meteorology

Current Local Radar

Temperature
77°F
Feels Like:
77°F
Dew Point	Humidity
70°F	79%

Mostly Cloudy

Wind Strength
Light	Moderate	Strong
South at 16 mph

Local Graphical Forecast (Updated: 06/20/25 9:26 pm)

Friday (6/20)
Day	Night


High	Low
	73

Saturday (6/21)
Day	Night


High	Low
95	78

Sunday (6/22)
Day	Night


High	Low
96	77

Monday (6/23)
Day	Night

	20%
High	Low
97	77

Tuesday (6/24)
Day	Night


High	Low
93	69

Wednesday (6/25)
Day	Night


High	Low
91	70

Thursday (6/26)
Day	Night


High	Low
88	68

Detailed Text Forecast (Updated: 06/20/25 9:26 pm)

Friday Night: Mostly clear, with a low around 73. South wind 10 to 15 mph, with gusts as high as 25 mph.

Saturday: Sunny and hot, with a high near 95. Heat index values as high as 106. Breezy, with a south southwest wind 15 to 25 mph, with gusts as high as 40 mph.

Saturday Night: Clear, with a low around 78. Breezy, with a south southwest wind 15 to 25 mph, with gusts as high as 40 mph.

Sunday: Sunny and hot, with a high near 96. Heat index values as high as 105. Breezy, with a south southwest wind 15 to 20 mph, with gusts as high as 30 mph.

Sunday Night: Clear, with a low around 77. South southwest wind 10 to 15 mph, with gusts as high as 30 mph.

Monday: Sunny and hot, with a high near 97.

Monday Night: A 20 percent chance of showers and thunderstorms after 1am. Mostly clear, with a low around 77.

Tuesday: A chance of showers and thunderstorms. Mostly sunny, with a high near 93.

Tuesday Night: A chance of showers and thunderstorms. Mostly cloudy, with a low around 69.

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

Wednesday Night: A chance of showers and thunderstorms. Mostly cloudy, with a low around 70.

Thursday: A chance of showers and thunderstorms. Mostly sunny, with a high near 88.

Thursday Night: A chance of showers and thunderstorms. Mostly cloudy, with a low around 68.

Friday: A chance of showers and thunderstorms. Mostly sunny, with a high near 85.

Campus Weather®:
Provided by College of DuPage
Built and Maintained by: COD Meteorology "NEXLAB"
Copyright © 2025

Contact COD Meteorology "NEXLAB":
Phone: 630-942-2590
Web: Contact Form

Contact College of Dupage:
Phone: 630-942-2800

College of DuPage:
Meteorology at COD
Earth Science at COD
COD AMS Student Weather Club
Programs of Study at COD
COD Admissions

Downers Grove South High School:
Home Page

SPC Convective Outlook Day 1

See Product Description

773
ACUS01 KWNS 210118
SWODY1
SPC AC 210116

Day 1 Convective Outlook CORR 1
NWS Storm Prediction Center Norman OK
0816 PM CDT Fri Jun 20 2025

Valid 210100Z - 211200Z

...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
NORTH DAKOTA AND MINNESOTA...

CORRECTED AREA MENTIONED IN FIRST SENTENCE OF THIRD PARAGRAPH OF
DISCUSSION

...SUMMARY...
A significant swath of severe winds is expected this evening and
tonight from the northern Plains eastward into the upper Mississippi
Valley.

...Northern Plains/Upper Mississippi Valley...
Water vapor imagery currently shows a shortwave trough moving
through the northern High Plains. Near the trough, a line of strong
to severe thunderstorms is ongoing across western North Dakota and
far northwestern South Dakota. As these storms move eastward across
the northern Plains this evening, a 60 to 70 knot mid-level jet will
move northeastward through the Dakotas. Lift associated the left
exit region of the jet, combined with a strongly unstable airmass
over the eastern Dakotas and western Minnesota will be favorable for
vigorous convective development. In response, the ongoing storms are
expected to grow upscale into a fast-moving severe MCS. The MCS is
forecast to track eastward across far northern South Dakota, North
Dakota and north-central Minnesota this evening.

At the surface, a 991 mb low will move northeastward across northern
South Dakota this evening. A tongue of very moist air with surface
dewpoints in the lower to mid 70s F will move northward into
southeastern North Dakota and central Minnesota this evening. Within
this moist airmass, strong instability is analyzed by the RAP with
MLCAPE in the 4000 to 5000 J/kg range. The ongoing line of severe
storms will move into this strong instability, and gradually
intensify over the next couple of hours. RAP forecast soundings
along the expected track of the MCS in southeastern North Dakota
this evening have moderate to strong deep-layer shear, long and
looped hodographs and steep mid-level lapse rates. This should be
favorable for supercells with large hail, wind damage and tornadoes.
A strong tornado may occur. Supercell development will be most
likely among cells that remain semi-discrete. However, a line is
expected to become more organized, which will make severe wind gusts
likely along its leading edge. Gusts above 80 mph will be possible
ahead of the more intense parts of the line. A Derecho may develop
across parts of the northern Plains and upper Mississippi Valley
this evening into tonight.

As the MCS moves into south-central North Dakota over the next few
hours, some short-term model forecasts develop discrete cells
further to the east near the moist axis in the vicinity of the
ND-SD-MN triple point. These storms are forecast to quickly expand
in coverage and move across northwest and north-central Minnesota,
ahead of the approaching MCS. These storms will likely be
supercellular, and be associated with large to very large hail, wind
damage and possible tornadoes.

A consolidation of the two areas of convection will likely take
place late this evening, with the severe MCS continuing to track
eastward across north-central Minnesota. A wind-damage swath is
expected as far east as northern Wisconsin and the western Upper
Peninsula of Michigan. Wind gusts of 85 to 105 mph will be possible
along parts of the MCS track.

...Southern Rockies/Central High Plains...
Water vapor imagery shows southwest flow over much of the
south-central U.S. A subtle shortwave trough appears to be located
in the southern Rockies, where convection has increased in coverage
over the last couple of hours. These storms will continue to move
northeastward into the High Plains this evening. Forecast soundings
from northeast New Mexico into northwest Kansas early this evening
have very steep low to mid-level lapse rates. This will likely
support a marginal threat for severe gusts, as the cells move into
the stronger instability over the High Plains.

..Broyles.. 06/21/2025

$$

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 2

See Product Description

346
ACUS02 KWNS 201732
SWODY2
SPC AC 201730

Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1230 PM CDT Fri Jun 20 2025

Valid 211200Z - 221200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR PARTS OF THE
NORTHERN GREAT LAKES INTO NEW YORK AND NORTHERN PENNSYLVANIA...

...SUMMARY...
Strong to locally severe storms are possible Saturday from the
northern Great Plains into the Upper Midwest and Great Lakes.

...Synopsis...
An amplifying pattern will occur on Saturday with a trough
strengthening across the west with a ridge building across the
eastern CONUS. Surface high pressure will be present across the
eastern CONUS with lee troughing across the central and northern
Plains ahead of the strengthening western CONUS trough.

...Great Lakes into the Northeast...
A strong MCS will likely be ongoing at the beginning of the period
across northern Wisconsin/western Upper Michigan. This MCS will
likely continue east through the morning with some wind/hail threat
across Upper Michigan and northern Lower Michigan before eventually
moving into Ontario. If this MCS continues to track along the
instability gradient, it could eventually arrive across
western/central New York during the afternoon/evening. However, this
threat is conditional given stronger forcing farther north in Canada
and strong building heights across the Northeast.

Additional thunderstorms may develop along the trailing
outflow/composite boundary during the afternoon as strong
instability builds into the northern Great Lakes. However, building
heights aloft should mostly suppress convection, with only isolated
storm coverage expected, if at all. If any storms can develop, the
environment would be very favorable for large hail, severe wind
gusts, and perhaps a tornado.

...Northern Plains into the Upper Midwest...
Very strong instability is expected to build across the northern
Plains on Saturday afternoon/evening. Very warm 700mb temperatures
(16C) and building heights aloft should keep thunderstorm activity
suppressed for much of the period. However, strong heating could
allow for isolated storm development which would likely be
supercellular with a hail and wind threat if this conditional threat
does materialize.

A few strong to potentially severe storms may be ongoing at the
beginning of the period across eastern Montana as a weak mid-level
trough traverses the region. Storm activity will likely remain
limited across eastern Montana for much of the day as heights build
aloft. However, additional storms may develop early Sunday morning
as troughing starts to advance east. Limited instability is the
primary limiting factor, but if sufficient instability can develop,
a few strong to severe storms may be possible (12Z NSSL WRF).

..Bentley.. 06/20/2025

$$

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

414
ACUS03 KWNS 201856
SWODY3
SPC AC 201855

Day 3 Convective Outlook
NWS Storm Prediction Center Norman OK
0155 PM CDT Fri Jun 20 2025

Valid 221200Z - 231200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM CENTRAL
NEBRASKA INTO THE UPPER MIDWEST...

...SUMMARY...
Severe thunderstorms may develop on Sunday from parts of the central
and northern Plains into the upper Midwest.

...Synopsis...
A strong mid-level ridge will amplify further across the eastern
CONUS on Sunday with a weak mid-level shortwave trough traversing
the northeast. A trough across the west will start to weaken and
move into the northern Plains during the period. At the surface,
troughing will extend along a frontal zone from northern Minnesota
to the central High Plains on Sunday.

...Great Plains into the Upper Midwest...
Very strong to extreme instability is forecast to develop across the
central and northern Plains on Sunday. However, very warm low-mid
level temperatures should keep the warm sector mostly capped for
much of the day. Therefore, thunderstorm development should be
mostly confined to the front. However, even along the frontal zone,
storm coverage may be mostly isolated given that forcing from the
mid-level trough may remain mostly northwest of the frontal zone. In
addition, the strong mid-level flow is forecast to remain mostly
post-frontal which may limit storm organization across Nebraska and
South Dakota.

Given the somewhat decoupled upper-level and low-level pattern, the
severe storm threat is more conditional across eastern South Dakota,
Nebraska, and southwest Minnesota with the higher probability storm
threat across eastern North Dakota and northern Minnesota where
cooler temperatures aloft, stronger shear, and stronger forcing
should be present. Severe wind gusts would be the most likely threat
from this activity.

...Parts of the Northeast...
Storms may be ongoing at the beginning of the period across the
Northeast as a mid-level shortwave trough shifts southeast. These
storms could be marginally severe with some damaging wind threat. In
the wake of this convection, very strong to extreme instability is
expected to build into the Northeast, but very warm lower
tropospheric temperatures and building heights aloft should suppress
additional afternoon thunderstorms.

..Bentley.. 06/20/2025

$$

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.

Non-Precip Statement

See Product Description

903
WWUS73 KLOT 210225
NPWLOT

URGENT - WEATHER MESSAGE
National Weather Service Chicago IL
925 PM CDT Fri Jun 20 2025

ILZ103>105-211230-
/O.CON.KLOT.XH.W.0001.250621T1500Z-250624T0500Z/
Northern Cook-Central Cook-Southern Cook-
Including the cities of Cicero, Orland Park, Calumet City,
Northbrook, Park Forest, Oak Lawn, Des Plaines, La Grange, Oak
Forest, Lemont, Palatine, Schaumburg, Oak Park, Chicago, and
Evanston
925 PM CDT Fri Jun 20 2025

...EXTREME HEAT WARNING REMAINS IN EFFECT FROM 10 AM SATURDAY TO
MIDNIGHT CDT MONDAY NIGHT...

* WHAT...Dangerously hot and humid conditions with high temperatures
each day well into the 90s and peak afternoon heat index values
around 105 degrees expected.

* WHERE...Central Cook, Northern Cook, and Southern Cook Counties.

* WHEN...From 10 AM Saturday to midnight CDT Monday Night.

* IMPACTS...Heat related illnesses increase significantly during
extreme heat and high humidity events. The magnitude of
anticipated heat, combined with oppressive warmth at night will
lead to hazardous conditions, particularly for the elderly and
those with pre-existing health conditions. Residents of the city
of Chicago can call 3 1 1 to request well being checks for elderly
friends or family members, or for information on finding the
nearest cooling center.

* ADDITIONAL DETAILS...Heat indices will likely remain in the 90s
late into the evening hours with overnight lows possibly
struggling to fall much below 80 degrees.

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.

Take extra precautions when outside. Wear lightweight and loose
fitting clothing. Try to limit strenuous activities to early morning
or evening. Take action when you see symptoms of heat exhaustion and
heat stroke.

&&

$$

ILZ003>006-008-010>013-019>021-023-032-033-039-106>108-INZ001-002-
010-011-019-211230-
/O.CON.KLOT.HT.Y.0001.250621T1500Z-250624T0500Z/
Winnebago-Boone-McHenry-Lake IL-Ogle-Lee-De Kalb-Kane-DuPage-La
Salle-Kendall-Grundy-Kankakee-Livingston-Iroquois-Ford-Northern
Will-Southern Will-Eastern Will-Lake IN-Porter-Newton-Jasper-
Benton-
Including the cities of Crystal Lake, Rensselaer, DeMotte,
McHenry, DeKalb, Mundelein, Naperville, Pontiac, Fairbury, Plano,
Bourbonnais, Crete, Byron, Peotone, Paxton, Woodstock, Aurora,
Kentland, Chesterton, Watseka, Elgin, Gary, Wheaton, Gibson City,
Lombard, Algonquin, Kankakee, Mokena, Channahon, Beecher, Coal
City, Ottawa, Carol Stream, Minooka, Oxford, Dwight, Gilman,
Belvidere, Gurnee, Yorkville, Morris, Streator, Manhattan,
Buffalo Grove, Valparaiso, Morocco, Dixon, Sycamore, Mendota,
Downers Grove, Waukegan, Plainfield, Hammond, Merrillville,
Rochelle, Bradley, La Salle, Oswego, Bolingbrook, Wilmington,
Portage, Fowler, Rockford, Roselawn, Joliet, Marseilles, and
Oregon
925 PM CDT Fri Jun 20 2025 /1025 PM EDT Fri Jun 20 2025/

...HEAT ADVISORY REMAINS IN EFFECT FROM 10 AM CDT /11 AM EDT/
SATURDAY TO MIDNIGHT CDT /1 AM EDT/ MONDAY NIGHT...

* WHAT...Heat index values around 105 degrees expected.

* WHERE...Portions of central, east central, north central, and
northeast Illinois and northwest Indiana.

* WHEN...From 10 AM CDT /11 AM EDT/ Saturday to midnight CDT /1 AM
EDT/ Monday Night.

* IMPACTS...Hot temperatures and high humidity may cause heat
illnesses.

* ADDITIONAL DETAILS...Heat impacts will be worsened by consecutive
days of hot and humid conditions, with overnight lows in the mid
70s providing little relief.

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.

Monitor the latest forecasts and warnings for updates.

&&

$$

The "Non-Precip Statement" is aimed at the general public and will detail notable weather that is either occuring or expected to occur, but does not relate to any form of precipitation. These would include but are not limited to high winds, reduced visibility or extreme temperatures.