textproduct: Central Illinois

KEY MESSAGES

- Areas of blowing dust will continue until winds subside this evening, producing localized visibilities of near zero. The most likely area for hazardous blowing dust channels is east of the Illinois River and north of I-70.

- A few thunderstorms are forecast over parts of central and southeast Illinois this evening into tonight, with the highest chances (30-50%) south of a Jacksonville to Paris line. More numerous storms are forecast tomorrow evening into early Tuesday morning.

- Each round of storms will carry a level 1 of 5 (marginal) risk for severe weather, with isolated large hail and locally damaging wind gusts the primary hazards.

DISCUSSION

Issued at 303 PM CDT Sun May 3 2026

This afternoon, blowing dust has resulted from strong southwesterly winds gusting over 40 mph. Several areas of near zero visibility have been reported in Sangamon, Logan, Christian, Macon, and Shelby counties at this point, with numerous reports of localized blowing dust in additional portions of central IL. The corridor of strongest winds looks as if it will shift eastward into east-central IL late this afternoon. Winds should decrease below 30 mph gusts by sunset alleviating blowing dust issues. Have issued a Blowing Dust Advisory for areas east of the Illinois River and north of I-70, as well as Knox and Peoria County where additional blowing dust reports have been received. Several localized Dust Storm Warnings have been issued.

HREF continues to advertise 500-1000 J/kg CAPE extending northeastward into parts of central IL up to around a Jacksonville to Robinson line. Along with 50 kts bulk shear, this could result in a few strong to severe storms after around 6 pm when a capping inversion is finally overcome along with weak low level convergence and warm advection associated with a strengthening low level jet. SPC continues a Marginal Risk for severe hail and 60 mph wind gusts in this area. CAMS depict this activity festering through the night, with gradually decreasing instability. Showers should decrease in the morning as the low level jet weakens. Instability looks to strengthen during the daytime Monday, although with largely absent forcing and a cap depicted in forecast soundings, chances for thunderstorms will be low until evening as a low level jet develops and a cold front approaches from the northwest. Overnight, another round of thunderstorms, possibly with large hail and locally severe winds is likely, and SPC has another Marginal Risk depicted for the entire forecast area. The front will likely stall out across the area Tuesday morning, however models depict very little instability redeveloping this far north and hence severe weather probabilities are low. Nevertheless, moderate amounts of precipitation could be seen Tuesday as a shortwave disturbance, southwesterly flow bringing precipitable water exceeding 1.25 inches, and a frontogenetical zone traverse the area. Ensemble mean precipitation ranges from around 1/2 inch west of I-55 up to 1.25 inch of rainfall south of I-70 on Tuesday, but under 5% chance of exceeding 2 inches.

Precipitation amounts and chances are lower Wednesday through Saturday as the main large scale trough axis shifts eastward and a cool, drier northwest flow resumes. Nevertheless, a few disturbances embedded withing the northwest flow could produce at least occasional light precipitation. The next impactful system could be next Sunday, however predominant ensemble guidance tracks this through the southern states and minimizes rainfall or severe weather impacts this far north.

Temperatures will trend strongly upward for Monday as southerly flow ahead of the approaching cold front impacts the area, and highs are forecast in the upper 70s to low 80s. Tuesday should see much cooler temperatures as the front crosses over much of the area by afternoon, along with cloudy, rainy conditions, and highs are forecast from upper 50s north of I-72 to mid 60s south of I-70. Upper 50s are forecast across the area Wednesday, then a warming trend brings highs back up to 70s/near normal by next weekend. While not anticipated at this time, any clear calm night late in the upcoming week could support some early morning frost. At this point, lows in the 40s appear more likely.

AVIATION /00Z TAFS THROUGH 00Z TUESDAY/

Issued at 616 PM CDT Sun May 3 2026

Southwest winds will decrease this evening, with speeds between 7-10 kts overnight. Scattered storms are possible this evening mainly south of I-72 and could affect KSPI for a few hours after 00Zs. Southwest winds pick up once again by mid to late morning with gusts increasing to around 25-30 kts through the afternoon. There is another low chance for isolated storms after 18Z, though confidence in timing/placement remains low and have not included at this time. Otherwise, VFR conditions are expected through the majority of the TAF period.

ILX WATCHES/WARNINGS/ADVISORIES

Blowing Dust Advisory until 7 PM CDT this evening for ILZ027- 029-031-037-038-041>057-061.