418
FXUS63 KLOT 032324
AFDLOT

Area Forecast Discussion
National Weather Service Chicago/Romeoville, IL
624 PM CDT Sun Aug 3 2025

.KEY MESSAGES...

- Hazy skies and patchy smoke from wildfires lingers today.

- A gradual increase in temperatures and humidity expected
  through the week.

&&

.DISCUSSION...
Issued at 238 PM CDT Sun Aug 3 2025

Through Sunday:

HRRR smoke forecasts for today have largely panned out with the
smoke across the northern half of the local area. Latest HRRR
runs suggest smoke will thin out further on Monday and based on
these forecasts, not planning to have any smoke or haze in the
forecast for Monday.

Some patchy fog will be possible early Monday morning, mainly in
rural locations, but no mention with this forecast.

A very weak mid level trough will pass across the region Monday
through Tuesday as a weak wave lifts north from the southeast
into the southern Great Lakes region. Models are in general
consensus with these trends and show isolated/scattered showers
from Monday afternoon through Tuesday evening, mainly across the
southeast cwa with the best coverage possibly east of the local
area. While there may be some diurnal decrease/increase with the
heating of the day, showers may continue Monday night into early
Tuesday morning. Despite these trends, blended guidance is dry
for all but Tuesday afternoon and made no changes. Instability
looks marginal for thunder, but maintained a chance of thunder
Tuesday afternoon.

The middle to end of the week is looking mainly dry and warmer
as southerly flow brings warmer temperatures back into the area.
High temps by Thursday may be around 90 and then lower 90s
Friday and Saturday. Still some question for how strong the
southerly winds will be and there may be lake breezes each
afternoon, at least along the IL lakeshore.

Models differ quite a bit on the arrival of a cold front later
next weekend or early next week. Too much uncertainty and too
far out to make any changes which have slight chance pops into
the northwest cwa by next Sunday. cms

&&

.AVIATION /00Z TAFS THROUGH 06Z MONDAY/...
Issued at 624 PM CDT Sun Aug 3 2025

There are no significant aviation weather concerns. Patchy
surface smoke will continue this evening, although based on
observations, concentrations increase north of the WI state
line. Mid and upper level haze/smoke will likely persist
through Monday.

East/southeast surface winds will trend light/variable this
evening, and may become light NNW at the Chicago-area terminals
for a time before they return out of the E/SE Monday morning.

A few showers are possible in the region Monday evening and
overnight. Chances remain too low for PROB mentions at this
time.

Carlaw

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...Air Quality Alert until midnight CDT tonight for ILZ005-ILZ006-
     ILZ012-ILZ013-ILZ020-ILZ021-ILZ103-ILZ104-ILZ105-ILZ106-
     ILZ107-ILZ108.

IN...Air Quality Alert until midnight CDT tonight for INZ001-INZ002-
     INZ010-INZ011.

LM...None.

&&

$$

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