Romeoville, Illinois 7 Day Weather Forecast
Wx Forecast - Wx Discussion - Wx Aviation
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NWS Forecast for Romeoville IL
National Weather Service Forecast for:
Romeoville IL
Issued by: National Weather Service Chicago, IL |
Updated: 1:26 pm CDT Jul 17, 2025 |
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This Afternoon
 Mostly Cloudy
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Tonight
 Decreasing Clouds
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Friday
 Sunny
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Friday Night
 Chance T-storms
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Saturday
 T-storms Likely
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Saturday Night
 Chance T-storms
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Sunday
 Chance T-storms
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Sunday Night
 Chance Showers
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Monday
 Chance T-storms
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Hi 76 °F |
Lo 60 °F |
Hi 84 °F |
Lo 69 °F |
Hi 86 °F |
Lo 69 °F |
Hi 82 °F |
Lo 67 °F |
Hi 84 °F |
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Hazardous Weather Outlook
This Afternoon
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Mostly cloudy, with a high near 76. Northeast wind around 10 mph. |
Tonight
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Mostly cloudy, then gradually becoming mostly clear, with a low around 60. Northeast wind 5 to 10 mph. |
Friday
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Sunny, with a high near 84. East northeast wind around 5 mph becoming south southeast in the afternoon. |
Friday Night
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A 40 percent chance of showers and thunderstorms, mainly after 1am. Mostly cloudy, with a low around 69. East wind around 5 mph becoming south southeast after midnight. |
Saturday
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Showers and thunderstorms likely. Mostly cloudy, with a high near 86. West southwest wind 5 to 10 mph, with gusts as high as 15 mph. Chance of precipitation is 70%. |
Saturday Night
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A 40 percent chance of showers and thunderstorms. Mostly cloudy, with a low around 69. |
Sunday
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A 30 percent chance of showers and thunderstorms, mainly after 1pm. Partly sunny, with a high near 82. |
Sunday Night
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A chance of showers. Mostly cloudy, with a low around 67. |
Monday
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A chance of showers and thunderstorms. Partly sunny, with a high near 84. |
Monday Night
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A chance of showers and thunderstorms. Mostly cloudy, with a low around 71. |
Tuesday
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A chance of showers and thunderstorms. Mostly sunny, with a high near 91. |
Tuesday Night
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Partly cloudy, with a low around 74. |
Wednesday
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Mostly sunny, with a high near 94. |
Forecast from NOAA-NWS
for Romeoville IL.
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Weather Forecast Discussion
557
FXUS63 KDVN 171807
AFDDVN
Area Forecast Discussion
National Weather Service Quad Cities IA IL
107 PM CDT Thu Jul 17 2025
.KEY MESSAGES...
- Cooler and less humid today and Friday.
- Active weather returns Friday night and through the weekend.
There are Marginal (level 1 of 5) Risks for severe weather
Friday Night through Saturday. Damaging wind and heavy
rainfall will be the primary risks.
- Ring of fire pattern to continue into next week, with building
heat and periodic chances of storms.
- Extreme heat likely next week beginning Tuesday and possibly
lasting through Friday, with 50-80% probabilities of heat
index values greater than 100 degrees.
&&
.SHORT TERM /THROUGH FRIDAY/...
Issued at 305 AM CDT Thu Jul 17 2025
Morning satellite loops and radar mosaics show an active area
of storms from northern KS into northern MO. These storms were
occurring along and north of an 850mb boundary supported by 2
weak shortwaves moving along the northern periphery of the 591
dm upper high and strong upper divergence evident by SPC
mesoanalysis. Closer to home, low stratus was making its way
south into the northwest portions of the CWA. At the surface,
cooler dewpoints in the upper 50s were also starting to make
their way south across IA!
Today/Tonight...latest CAMs and radar/observational trends keep
the aforementioned storms to move along the far southern
portion of the CWA or just to our south early this morning.
Have lowered PoPs to slight chance with the entire area seeing
a dry forecast after 13z. At the same time, CAA clouds will drop
south with cooler dewpoints advecting into the region. This
will result in a much welcomed less humid day today, with
afternoon highs only in the 70s! However, if clouds scatter out
faster than forecast, then these readings may be a bit low. In
any case, temperatures will be cooler than in recent days.
Tonight, continued clearing skies and low level easterly flow
will allow temps to drop into the upper 50s to low 60s
overnight.
Friday...slightly warmer temperatures and humidity levels will
be seen, as surface high drifts over the Great Lakes while a
weak surface low develops over western NE. Afternoon highs to
top out in the lower 80s.
&&
.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
Issued at 305 AM CDT Thu Jul 17 2025
Friday Night-Monday...active zonal flow with upper high across
the southeastern CONUS retrograding west. This will bring a
series of waves through the forecast area during this period.
Latest 00z guidance suggests a potential MCS may develop Friday
night over the northern Plains and track east towards the CWA
Saturday morning. At the same time, a strengthening LLJ may
allow for additional development ahead of this feature overnight
per the 00z RRFS model. As a result, SPC has a Day 2 Marginal
(level 1 of 5) risk for severe weather west of a Manchester to
Iowa City line. Damaging wind, heavy rain, and lightning will
be the primary threats with this activity. Ring of fire
pattern reloads once again Saturday afternoon and evening with
more storms in or near the CWA. A very unstable atmosphere
characterized by SBCAPEs over 2500 J/Kg, PWs over 2", and
strengthening westerlies to support another severe risk. SPC has
another Day 3 Marginal (level 1 of 5) risk for severe weather
for Saturday across all but the far northern counties. Some 00z
model solutions and NSSL ML guidance suggest the severe risk may
be even higher Saturday, but uncertainties in previous day`s
convection and EML strength preclude a higher risk at this time.
Another concern that will need to be watched closely is the
heavy rain potential and subsequent river rises. Rain rates over
2"/hr are possible and if storms train over the same area, then
flash flooding may occur. There is a large QPF footprint as
indicated by WPC and all ensemble solutions (GEFS, GEPS, ECE)
through this weekend. High probabilities (50-80%) of at least 1"
of rain is shown, allowing for renewed rises on area rivers and
streams. Stay weather aware this weekend!
Tuesday Onward...a strong upper level ridge will build into the
central CONUS pushing the active storm track further north into
the upper Midwest. This unfortunately will allow heat and
humidity to return in earnest with extreme heat becoming more
and more likely. The probabilities of heat indices over 100
degrees has now increased into the 50-80% category Tuesday and
Wednesday across much of the area. In addition, over 60% of all
the members of the GEFS/GEPS/ECE show 100+ degree values at MLI
Tuesday-Thursday. If that were not enough, CPC has a moderate
to high risk of hazardous temps July 24th-25th. Heat headlines
will eventually be needed next week for this.
&&
.AVIATION /18Z TAFS THROUGH 18Z FRIDAY/...
Issued at 1249 PM CDT Thu Jul 17 2025
MVFR cigs have been slow to erode today and will likely mix out
later today to VFR cigs. Do think we keep these clouds for most
of the period, however with VFR flight rules. Winds are expected
to remain below 10kts.
&&
.CLIMATE...
Issued at 309 AM CDT Thu Jul 17 2025
The Climate Prediction Center (CPC) 8-14 day temperature
outlook has 80-90% combined probabilities of near/above normal
temperatures for the July 24th-30th period for the entire CWA.
Normal highs for this period are in the middle 80s and normal
lows are in the middle 60s. In addition, there is a 60-70%
combined probability of near/above normal precipitation along
and north of Hwy 20 for this same period. Active and warm
weather will be the rule for the rest of July.
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...None.
IL...None.
MO...None.
&&
$$
SHORT TERM...Gross
LONG TERM...Ervin/Gross
AVIATION...Gibbs
CLIMATE...Gross
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