textproduct: Central Illinois

KEY MESSAGES

- Over the coming week, mean temperatures are anticipated to stay close to seasonal norms, with daytime peaks mostly reaching the mid-70s and overnight minimums near the lower 50s. In contrast, the region is expected to see a drier pattern, with total rainfall likely totaling around half an inch, falling below typical weekly averages.

- Concerns regarding blowing dust are growing for the middle of next week, especially throughout Tuesday and Wednesday, for locations north of Interstate 70 and east of the Illinois River. There is currently a high (50-80%) probability of wind gusts exceeding 30 mph during this period. Combined with active agricultural field work and relatively dry soil conditions, these winds could create corridors of significantly limited visibility on interstates and highways.

DISCUSSION

(through next Saturday) Issued at 101 PM CDT Sat May 9 2026

Mid-level water vapor imagery from this afternoon shows a compact shortwave trough embedded within the broader meridional flow over eastern Canada, currently moving through the Great Lakes. This system is forecast to drive a backdoor cold front across central Illinois tonight. However, a lack of significant moisture return, limited instability, and weak surface convergence along the boundary are expected to prevent widespread precipitation. According to recent HREF guidance, there is a low probability (40% or less) for measurable rain as the front passes this evening. The most favorable conditions for light rainfall, potentially up to one-tenth of an inch, appear to be south of a line from Quincy to Terre Haute, where guidance indicates a few hundred joules of MUCAPE may develop late tonight.

As an upstream ridge and accompanying surface high pressure establish themselves over the Great Lakes, a transition to cooler, drier air is expected to occur from tonight through Sunday night. According to NBM deterministic guidance, temperatures are forecast to reach the mid-60s on Sunday afternoon before dropping into the low 40s by Sunday night.

A pronounced surge of low-level warm advection will sweep across the Plains and into the Midwest from Monday into Tuesday, leading to a notable rise in both temperatures and dewpoints ahead of an approaching frontal system. While global ensembles (GEFS, ENS, and GEPS) indicate a high (60-80%) likelihood of precipitation by Tuesday evening, NBM rain chances appear to be lagging behind this trend. QPF from both the NBM and Grand Ensemble suggest light accumulations, generally ranging from a trace to one-quarter inch based on 25th-75th percentile ranges. However, if the frontal passage interacts with any elevated instability, locally higher rainfall totals or convectively- enhanced pockets could develop. Despite these possibilities, severe weather is not expected with this system.

The potential for blowing dust or dust storm-type conditions may pose a more significant threat for the middle of next week. Analysis of model soundings reveals deep boundary layer mixing, which is expected to generate gusty winds on Tuesday afternoon prior to the cold front's arrival, and again on Wednesday afternoon following the frontal passage. The mean wind gusts from the GEFS, EPS, and NBM consistently support the likelihood of gusts exceeding 30 mph. These high winds will coincide with relatively dry soils and peak agricultural activity across the region. Any rainfall occurring Tuesday evening may be insufficient to effectively settle the dust. Consequently, we will closely monitor this situation through early next week and may issue Blowing Dust headlines for Tuesday and Wednesday, as visibility could be significantly reduced along various highways and interstates.

A shift toward a hotter, above-normal temperature regime is expected to begin on Thursday. As high pressure and a ridge develop over the area, dry conditions will prevail from Wednesday through Friday morning. By the conclusion of next week, temperatures are projected to climb deep into the 80s.

Mid-range models continue to indicate that a strong influx of Gulf moisture will transport warmer and more humid air into the Midwest by late Friday into next Saturday. This trend is expected to trigger a period of increased thunderstorm activity, with thermodynamic and kinematic profiles potentially becoming even more favorable for severe weather development. This significant warming trend will be accompanied by brisk southerly winds, which may cause blowing dust issues to return across parts of central Illinois by late next week, though the severity of these impacts will likely be influenced by the amount of rainfall received late next week.

AVIATION /18Z TAFS THROUGH 18Z SUNDAY/

Issued at 1206 PM CDT Sat May 9 2026

This afternoon, a cold front is draped from southern WI southwest across southern IA. Ahead of the front, breezy southwest to west winds will prevail across central Illinois, with gusts picking up to around 20-25 kt this afternoon. The front will settle over central Illinois tonight with winds dropping off within the frontal trough. The exception will be a brief window of N/NE winds overnight associated with a lake breeze boundary from Lake Michigan. A few light showers are possible in the vicinity of the front tonight, mainly along the I-72 corridor and south, but low confidence/coverage precludes more than a prob30 mention at this time.

ILX WATCHES/WARNINGS/ADVISORIES

None.