textproduct: Central Illinois

KEY MESSAGES

- Dramatically warmer temperatures are expected by Friday, with afternoon highs likely surging into the 60s, ushered in by gusty southwest winds (25-35 mph). These conditions, combined with afternoon relative humidity possibly dropping below 30%, may result in elevated fire danger, especially across west-central Illinois.

- The probability for impactful wintry precipitation to return Sunday into Sunday night is medium-to-high (50-70%).

- For the first week of March, the Climate Prediction Center indicates a medium-to-high likelihood (a 50-70% chance) of experiencing both above-normal temperatures and above-normal precipitation.

DISCUSSION

Issued at 326 AM CST Thu Feb 26 2026

Precipitation will rapidly diminish this morning as the primary upper-level shortwave and associated surface low have moved into the Tennessee Valley. With the more favorable mesoscale banding (FGEN) and cloud ice nuclei exiting to the east, we are now left with patchy freezing drizzle in areas where residual low-level vertical motion (omega) and low-level RH overlap.

A significant warm-up is expected, starting this afternoon and lasting through Friday. This is due to a broad ridge axis traversing the central U.S., which will lead to increased mid- level heights. The unseasonably warm temperatures will be advected into the Midwest by strengthening southwest winds preceding an approaching cold front, with down-slope flow off the Rockies providing an additional boost. Afternoon highs today will warm near 50 degrees before surging well into the 60s on Friday.

The risk for elevated fire danger returns Friday, particularly across west-central Illinois. The combination of gusty winds, warm temperatures, dry fuels, and low relative humidity warrant attention given the ongoing drought conditions. A quick glance at model soundings ahead of the cold front reveals deep boundary layer mixing amid mostly clear skies. Such a signal may push us to favor the upper tails of temperature and wind gust guidance while simultaneously favoring the lower tails of dewpoint guidance. The net result pushes us close to a Fire Weather Watch for a portion of our area as afternoon RH values potentially fall below 30% amid 25-35 mph wind gusts and drying fine fuels.

With the cold front sagging southward late Friday night and early Saturday morning, a sharp temperature gradient will develop across the region. Most of central Illinois, situated on the cool side of the boundary, is expected to experience highs in the 40s. By contrast, areas on the warm side, primarily in southeast Illinois, are once again forecast to approach 60 degrees.

Attention then turns to an impactful winter storm targeting the central U.S. between Sunday and Monday. The synoptic pattern is of particular interest: a large surface high situated over the Great Lakes, coupled with a signal for overrunning precipitation across the Central Plains, Ozarks, and Mid-Mississippi Valley. This specific setup is climatologically favorable for snow and ice across Illinois. While model temperature forecasts for this period still show too much variation to confidently pinpoint the precise potential for ice versus sleet or snow, the overarching pattern bears watching.

Regardless of what happens to start next week, mid-range model guidance has remained steadfast in its depiction of moderating temperatures and elevated potential for wet weather by the middle of the week. This pattern change will be driven by deep troughing that evolves across the western third of the CONUS, which will promote a steady fetch of Gulf moisture and numerous chances for showers and thunderstorms across the lower- and mid-Mississippi Valley through the end of next week.

MJA

AVIATION

(For the 18z TAFs through 18z Friday Afternoon) Issued at 1122 AM CST Thu Feb 26 2026

VFR conditions are expected through the period, with a mid-level cloud deck shifting through this afternoon. Winds are in the process of turning from southeasterly (at 1720z) to southwesterly by 18 or 19z, and will remain southwesterly through the rest of the period. Wind speeds will generally be less than 10 knots through tonight, then start to increase towards late morning Friday. Gusts will increase to 20-25 kts towards the end of this TAF period, and even stronger gusts are anticipated between 18z Fri and 00z Sat.

Erwin