Peoria, Illinois 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

065
FXUS63 KILX 191847
AFDILX

Area Forecast Discussion
National Weather Service Lincoln IL
147 PM CDT Thu Mar 19 2026

.KEY MESSAGES...

- Unseasonably warm conditions will continue through the weekend,
  with daily high temperatures reaching the 70s. There is a 60%
  to 80% chance that temperatures will reach or exceed 80 degrees
  on Sunday, especially for areas south of Interstate 72.

- A cold front on Sunday brings a low chance (20% near I-70) for
  thunderstorms; if storms develop, a few could become strong to
  severe.

&&

.DISCUSSION...
Issued at 143 PM CDT Thu Mar 19 2026

Unseasonable Warmth Dominates Through the Weekend...

A stout upper-level ridge centered over the Desert Southwest will
be the main driver of our weather pattern through the weekend,
effectively pushing the polar jet stream well into Canada. This
setup places Central Illinois firmly on the warm side of the jet,
allowing for a significant period of unseasonable warmth. Expect
daily high temperatures to climb into the 70s starting today and
continuing through Sunday.

A minor weather feature will pass to our north on Friday. A
clipper system digging across the Great Lakes will induce a fresh
breeze across the area. We do not anticipate any precipitation
from this feature locally, but a trailing cold front will result
in a shift in wind direction. Southwest winds in the morning will
give way to breezy northwest winds in the afternoon hours.

Pattern Change and Severe Potential Sunday...

The upper ridge is forecast to begin breaking down late this
weekend in response to an approaching, stronger shortwave trough
digging across the Upper Midwest and Great Lakes. Model guidance
shows some notable differences in the surface response. The 12Z
GFS is aggressive, developing a sub-1000mb low tracking across
northern Illinois. In contrast, the GEM and ECMWF are less intense
and a little faster, depicting a stable wave along the baroclinic
zone that fills as it crosses the state. Regardless of the
surface lows exact strength, an attendant cold front will push
across Central Illinois during the day Sunday, marking the end of
the extended warmth.

This frontal passage also provides our next chance for
precipitation, albeit a low one currently. Forecast soundings
suggest weak to moderate instability will develop ahead of the
front Sunday afternoon and evening, coinciding with strong deep-
layer shear. However, a stout capping inversion and the
displacement from the main upper-level forcing are the primary
limiting factors for widespread convective development. If the cap
can be sufficiently eroded, the highly favorable parameter space
does support a risk of severe storms. Forecasters will continue to
monitor this potential closely over the next 48 hours.

Meanwhile, Sunday presents the best opportunity for temperatures
to reach or exceed the 80-degree mark. NBM probabilities for
reaching 80 degrees or higher are highest across the southern half
of the CWA, ranging from around 30 percent in Galesburg to 60
percent in Springfield and up to 80 percent in Lawrenceville.

Brief Cooldown Followed by a Gradual Warm-up Next Week...

Temperatures will briefly return closer to seasonal norms on
Monday as high pressure builds southeastward from the Canadian
Prairies. North winds behind the cold front will keep Monday
afternoon highs limited to the 50s. The surface ridge axis then
shifts east starting Tuesday, allowing the baroclinic zone to lift
back north across the region. This pattern shift will initiate a
gradual warming trend through the rest of the work week. The main
jet stream will remain overhead for much of the week, with low-
amplitude waves potentially bringing scattered showers. However,
model agreement is currently poor, and the blended NBM guidance
reflects this uncertainty, keeping PoPs low (generally below 15
percent) through the middle of next week.

Deubelbeiss

&&

.AVIATION...  (For the 18z TAFs through 18z Friday Afternoon)
Issued at 1212 PM CDT Thu Mar 19 2026

Low pressure will dig across the Great Lakes this evening and
overnight. Ahead of the low, light southerly winds 6-11kt will be
in place across central Illinois. Winds will veer to SWerly ahead
of an approaching cold front Friday morning, then veer to NWerly
behind the cold front Friday afternoon. No precip is expected with
the front and VFR conditions are likely through the period.

Deubelbeiss

&&

.ILX WATCHES/WARNINGS/ADVISORIES...
None.
&&

$$