Chicago, Illinois 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

939
FXUS63 KLOT 242330
AFDLOT

Area Forecast Discussion
National Weather Service Chicago/Romeoville, IL
630 PM CDT Sun May 24 2026

.KEY MESSAGES...

- Potential for dense fog to develop over Lake Michigan and
  affect locations along the shore through tonight. Patchy fog
  possible elsewhere through sunrise Monday.

- Above normal temperatures favored through next weekend, though
  cooler near Lake Michigan. Rain chances appear low during this
  period, with chances for showers and storms confined to
  Wednesday.

&&

.DISCUSSION...
Issued at 144 PM CDT Sun May 24 2026

High pressure centered just west of the area this afternoon
will drift overhead tonight, setting the stage for light/calm
winds as skies remain primarily clear. With some (potentially
dense) fog already evident over Lake Michigan in the wake of
today`s rain, will need to closely monitor trends late this
afternoon and especially this evening along the Illinois shore
as backing low-level flow would then begin advecting any fog
onshore. Additionally, patchy shallow fog is possible overnight
where rain was more prevalent (around and east of I-55) today.
And while low-level will begin veering SSW later tonight subtle
WAA acting on any shallow fog south of I-80 would start
advecting northward toward the Chicago metro around sunrise. Any
shallow fog will quickly dissipate after sunrise.

A small wave/complex of convection over Nebraska and South
Dakota late today will drift toward southern Wisconsin and far
northern Illinois Monday morning and early afternoon. The
thermodynamic environment will become increasingly unfavorable
with eastward extent across Iowa and especially east of the
Mississippi River. Expectations are for some mid-level clouds
and perhaps a few rogue sprinkles in the far northwest CWA
midday.

A massive Hudson Bay high developing ahead of a highly
amplified ridge over the central/northern Great Plains into
central Canada will drift southward midweek into next weekend.
Guidance remains mixed on how far north a southwestern CONUS
trough becomes cutoff over the southern Great Plains or Lower
Mississippi Valley this week. Latest indications are that a vast
majority of moisture/forcing associated with the cut off system
will remain south of the area, with the exception of a backdoor
front bringing a period of showers and some storms to the area
Wednesday. Otherwise, dry conditions and seasonably warm
temperatures (cooler near the lake) would be expected through
much of the period.

Kluber

&&

.AVIATION /00Z TAFS THROUGH 06Z TUESDAY/...
Issued at 630 PM CDT Sun May 24 2026

Primary forecast concern is fog potential overnight into early
Monday morning.

A slow moving lake breeze has moved west of ORD/MDW late this
afternoon and will likely dissipate near or east of a DPA/LOT
line with sunset. While patchy fog will be possible across much
of the area, this boundary may allow for a narrow and localized
area of thicker fog to develop overnight, though confidence is
low. Dense fog is expected over Lake Michigan which may move
along the shore. Opted to make no changes to the current
forecast with prevailing mvfr vis at GYY/DPA and only 6sm at
ORD/MDW. Further northwest at RFD, fog potential seems to have
diminished some but is still possible. Any fog that does form
will quickly dissipate after sunrise Monday morning.

Northwest winds continue west of the lake breeze but winds will
eventually become light southeast across the entire area later
this evening and then light southerly overnight, with many areas
possibly becoming light and variable or calm. Winds look to turn
southwest or possibly west/southwest after daybreak and will
then slowly turn back southerly by early afternoon and possibly
south/southeast by late Monday afternoon/early Monday evening. A
lake breeze is expected Monday afternoon, but confidence is low
for how far inland it may move. cms

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...None.
IN...None.
LM...None.

&&

$$

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