713
FXUS63 KLOT 281908
AFDLOT

Area Forecast Discussion
National Weather Service Chicago/Romeoville, IL
208 PM CDT Tue Jul 28 2026

.KEY MESSAGES...

- Dangerous swimming conditions due to large waves and strong
  currents will continue through Wednesday morning.

- Rain chances return by Friday and continue into Saturday.

&&

.DISCUSSION...
Issued at 208 PM CDT Tue Jul 28 2026

Conditions are quiet and comfortable out there this afternoon.
Temperatures range from the upper 70s to middle 80s with a nice
breeze out of the NNE. Dry air advection from high pressure
dropping in from the north is clearing away a lake-enhanced low
stratus deck and leaving behind sunny skies. The clear skies and
dry air will allow early morning lows to drop into the upper
50s to around 60 tomorrow, a little warmer in and around
Chicago. That high will be centered over the region tomorrow and
Thursday and keep rain chances away through the middle part of
the week. Highs are forecast in the lower and middle 80s
tomorrow and Thursday.

Water vapor imagery this afternoon showcases an apparent
shortwave Pacific trough moving onshore over California. The
wave will quietly lift northeast across the Rockies over the
next couple of days. By late Thursday, as the wave gets
sandwiched between two centers of high pressure, it will quickly
wind up into a closed midlevel low over the northern Plains
before propagating southeast into the Midwest. The surface
response will be a deepening center of low pressure progged to
move across IL late Friday into Saturday. A system of showers
will blossom around the developing low over the Plains on
Thursday and rain could move into our area from the west as
early as Friday morning. Chances build from west to east Friday
afternoon and evening as coverage looks to overspread the area.
Widespread showers are then expected Friday evening into
Saturday morning. There`s some uncertainty in what Saturday
afternoon/evening will look like, but more scattered showers are
favored. Sometime Saturday-Sunday, the wave will become cutoff
from the jet and wander around the lower Midwest into early next
week. While it`s favored to stall over the Tennessee Valley and
keep the recurring rain chances south of our area early next
week, periodic showers may continue into portions of our CWA,
especially southern CWA, on Sunday and Monday.

As far as thunderstorm chances go late this week, cool low
level air wrapped up in the low will result in weak lapse rates
through the column and little to no instability for noteworthy
thunder coverage. Nonetheless, a few embedded storms will
certainly be possible here and there. If the low can take a
farther north track, then chances would increase for embedded,
non-severe storms for areas in the low`s warm sector, but such a
track is an outlier among medium-range guidance. Despite the
lack of thunder, deep layer moisture and dynamic forcing with
the stacked low could result in prolonged periods of soaking
rainfall; all available deterministic camps resolve a widespread
1-2"+ of QPF through Sunday morning.

Afternoon temperatures are forecast in the upper 70s and lower
80s this weekend. A gradual warming trend is expected next week
with highs favored to climb back toward 90 by the end of the
week.

Doom

&&

.AVIATION /18Z TAFS THROUGH 00Z THURSDAY/...
Issued at 1227 PM CDT Tue Jul 28 2026

There are no key concerns to highlight for the 18Z TAF period.

The MVFR deck off the lake that impacted the Chicagoland sites
this morning has scattered out for the day. Only GYY remains
MVFR and looks to go VFR by 19Z. Meanwhile, NNE winds between 10
and 15 kt will occasionally gust to around 20 kt this afternoon
before subsiding for the evening and night. Expect light NE
winds during the day on Wednesday. Expect VFR throughout the
period.

Doom

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...Beach Hazards Statement through Wednesday morning for ILZ006-
     ILZ103-ILZ104.

IN...Beach Hazards Statement through Wednesday morning for INZ001-
     INZ002.

LM...Small Craft Advisory until 7 AM CDT Wednesday for the IL and
     IN nearshore waters.

&&

$$

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