Wheaton, Illinois 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

808
FXUS63 KLOT 191911
AFDLOT

Area Forecast Discussion
National Weather Service Chicago/Romeoville, IL
211 PM CDT Thu Mar 19 2026

.KEY MESSAGES...

- Spring-like temperatures through the early weekend, though
  Lake Michigan will moderate temperatures along the shoreline.

- Cooler temperatures are expected early next week after a cold
  front passes on Sunday

&&

.DISCUSSION...
Issued at 211 PM CDT Thu Mar 19 2026

GOES-19 water vapor imagery shows moisture over the inner
mountain west riding over top of an upper level ridge located
over the desert southwest. This ridge is expected to remain
mostly in place through Saturday, if not expand and slide
eastward slightly. Today, clear skies has cause temperatures to
over-achieve and climb into the lower 60s (inland areas) earlier
than expected. In contrast, onshore flow has capped max
temperatures for the city of Chicago and other areas closer to
Lake Michigan in the 40s. As the ridge expands, mid level warm
air advection is projected to increase 850 mb temperatures to 15
to 18C. Temperatures will continue to warm up tomorrow and
Saturday with highs in the 60s and 70s. Shoreline locations will
remain slightly cooler with the lake influencing the onshore
flow. Moisture riding over the ridge and down the northwest flow
may allow periods of clouds at times through the weekend, but
no precipitation is expected.

The upper level ridge will begin to flatten into Sunday with
quasi-zonal flow projected to develop over the central CONUS
ahead of the arrival of an upper level trough. This trough is
expected to have a surface cold front associated with it that
will pass over northern Illinois. Confidence lowers dramatically
in timing of the front and high temperatures for Sunday given
the disagreement between models and even with the run-to-run
consistency of individual models. If later runs verify, the
current high temperature could be underdone, whereas if that
front comes racing down the lake, much cooler temperatures
could arrive much sooner and drop temperatures substantially
(especially along the lakefront). Lastly, the NBM is still
showing a pool of moisture moving in with the front, so no
changes to the slight chance PoPs that the blend gives;
especially since amounts look fairly limited.

A cooler air mass is expected behind that front. Lows
potentially could drop below freezing, while afternoon
temperatures only climb into the 40s. Models are suggesting that
another ridge will move out of the southwest through the middle
of next week. That should help temperatures moderate and start
to warm again back into the 50s. With northwest flow over the
area, a stray impulse cannot be ruled out mid/late next week
that could bring a chance for rain, but without any real model
consensus, confidence is low.

DK

&&

.AVIATION /18Z TAFS THROUGH 00Z SATURDAY/...
Issued at 1200 PM CDT Thu Mar 19 2026

There are no significant aviation forecast concerns anticipated
through the period.

VFR conditions are expected through much of the TAF period,
with the only exception being the possibility for some bkn MVFR
CIGS moving in off the lake later Friday afternoon. Winds
should largely remain under 10 kts from the east this afternoon,
before turning southwesterly later tonight. Winds should trend
northwesterly 10 to 15 kt Friday morning, then flip northeast
off the lake in the afternoon.

KJB

&&

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

&&

$$

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