textproduct: Central Illinois

KEY MESSAGES

- Gusty winds (30-40 mph) will usher in much warmer temperatures today. This, combined with afternoon relative humidity potentially near 30%, will lead to elevated fire danger, particularly across west-central into southern Illinois.

- There is a high (60-70%) chance for light wintry precipitation Wednesday night into Thursday morning in areas north of Interstate 70.

- Additional wintry precipitation is possible (30-50% chance) early next week.

DISCUSSION

(through next Tuesday) Issued at 239 AM CST Tue Feb 24 2026

A brief warm-up will occur today as a broad ridge axis moves across the central U.S., prompting an increase in mid-level heights. The warmer temps will be advected into the Midwest by strengthening southwest winds ahead of an approaching cold front, with an added boost from down slope flow off the Rockies.

There is a limited risk for elevated fire danger this afternoon, particularly across west-central into southern Illinois. This is due to forecast highs well into the 40s, accompanied by gusty winds of 30-40 mph. The combination of gusty winds, mild temperatures, dry fuels, and low afternoon relative humidity (around 30%) warrant attention given the ongoing drought conditions. However, increasing high clouds could potentially mitigate this threat by decreasing boundary layer mixing and subsequently raising relative humidity values, introducing some uncertainty to the overall fire potential. For now, we have issued a special weather statement (SPS) highlighting the fire concerns.

A cold front will settle just south of the region late tonight, keeping us on the cool side of the boundary on Wednesday with afternoon highs near 40 degrees. The boundary will then lift back northward a bit late Wednesday night and into Thursday morning. This shift will occur as a strong shortwave and associated surface low track across the Corn Belt and into the Ozarks, bringing forth our next weather-maker.

Forecasting the midweek event remains challenging due to several uncertainties, primarily the placement of the strongest mid-level frontogenesis and the precise thermal profile, which will dictate precipitation type. The good news is that despite the forecast uncertainty, most of our potential outcomes suggest limited, sub- advisory impacts.

While global deterministic models (GFS and ECMWF) have recently shifted the axis of heaviest QPF southward, now generally south of I-74, some longer-range 00z CAMs (RRFS and NAMNEST) continue to focus the potential for heavier precipitation near or north of I-74. The latest NBM guidance should be considered too broad in its QPF output because it blends these divergent solutions.

Given that this is expected to be a mesoscale banded precipitation event, we are likely still just outside the window where probabilistic guidance is most effective in pinpointing the narrow axis of 1-3 inches of potential snowfall. However, the 12z HREF guidance later this morning should offer a better resolution of the pattern.

South of wherever the banded snow develops, a mixed-phase precipitation event is still anticipated, with a transition to sleet or freezing drizzle possible late Thursday morning as the system exits eastward.

Quiet and mild weather returns by the end of the week as a ridge of high pressure settles in behind the departing midweek storm system. Temperatures for Friday and Saturday look to be near 60 degrees until a backdoor cold front sags across the area by late Saturday night, pushing temperatures back down toward seasonal norms for Sunday and Monday.

A somewhat concerning pattern for freezing rain is evolving for early next week. The synoptic setup, featuring a large surface high over the Great Lakes and a signal for overrunning precipitation across the Central Plains, Ozarks, and Mid- Mississippi Valley, climatologically favors icing conditions. While the model spread in temperatures for this period is currently too large to have high confidence in the icing potential, the overall pattern is noteworthy. On a lighter note, given the dry winter, some areas might simply welcome any precipitation, regardless of whether it is rain or freezing rain.

MJA

AVIATION

(For the 06z TAFs through 06z Tuesday Night) Issued at 1032 PM CST Mon Feb 23 2026

VFR through the period with increasing high clouds tonight and mid level clouds Tuesday. Surface ridge axis was pushing east of the area, and will allow light S/SW flow to develop overnight. Winds will become gusty by mid morning as the pressure gradient tightens, with gusts increasing to 30-35 kt and veering SSW midday through the afternoon. Gusts are forecast to diminish around 00z.

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ILX WATCHES/WARNINGS/ADVISORIES

None.