Chicago, Illinois 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

241
FXUS63 KLOT 201120
AFDLOT

Area Forecast Discussion
National Weather Service Chicago/Romeoville, IL
620 AM CDT Tue Oct 20 2026

.KEY MESSAGES...

- Some ground fog may develop within 10-15 miles of Lake
  Michigan during early morning hours the next few days. Any fog
  would then quickly dissipate after sunrise.

- An extended period of dry and above to much above average
  temperatures is expected through the upcoming weekend.

&&

.DISCUSSION...
Issued at 154 AM CDT Tue Oct 20 2026

No significant weather is expected through the upcoming weekend
with above to much above average temperatures each day.
Generally light winds should allow weak lake breezes to form
each of the next several afternoons, but only result in slightly
cooler conditions right near the lake. A modest increase in
moisture in the wake of the afternoon lake breezes could allow
for some ground fog to form during the early morning hours the
next few days. Otherwise, look for mostly sunny conditions for
the remainder of the work week.

- Borchardt/Izzi

&&

.AVIATION /12Z TAFS THROUGH 18Z WEDNESDAY/...
Issued at 620 AM CDT Tue Oct 20 2026

Key Aviation Messages for the current TAF period:

- Patchy fog, locally dense, expected through sunrise today for
  Chicago terminals north of a KARR to KMDW line

- Another chance for fog tomorrow morning for terminals closer
  to the lake

A locally dense fog bank is slowly moving west-southwest through
northeastern Illinois this morning. The densest portion of this
fog dropped visibilities at KORD down to 1/8SM. This fog is
expected to impact terminals north of a KARR to KMDW line. Some
MVFR vis may develop south of this border, but there is lower
confidence in dense fog currently. Once the sun rises,
visibilities are expected to improve back to VFR conditions.

Winds are expected to be light and mostly out of the east-
southeast today. Clear skies are expected tonight with light,
if not calm, winds across the area leading to another chance
for fog developing closer to the lake, similar to what is
happening this morning. A TEMPO was added for tomorrow morning
introducing reduced vis which can be adjusted in later TAF
packages with updated confidence in fog development.

DK

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...Dense Fog Advisory until 9 AM CDT this morning for ILZ005-
     ILZ006-ILZ013-ILZ103-ILZ104.

IN...None.
LM...None.

&&

$$

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