textproduct: Central Illinois

KEY MESSAGES

- A period of wintry precipitation will occur tonight into early Monday morning. Snowfall will range from 1 to 1.5 inches along and south of a Rushville to Paris line...with a narrow ribbon of potentially up to 2 inches along a Jacksonville to Mattoon line. A light glazing is also possible late tonight in southeast Illinois.

- Strong thunderstorms are possible Wednesday and again Friday. The highest probability for severe weather (greater than a 15% chance) will focus from northeast Texas into Missouri.

- Beneficial rainfall is on tap for central and southeast Illinois over the next week. The 00z Mar 1 LREF indicates a 50-70% chance of greater than 2 inches of rain from today through next Sunday along and south of a Quincy to Bloomington line.

UPDATE

Issued at 810 PM CST Sun Mar 1 2026

Forecast is largely on track regarding snow and light mixed precip tonight. Dry air below the 700 mb level will take some time to saturate, but after it does later this evening snow will quickly spread east across the central CWA. Based on latest high- resolution guidance, still appears the "heavier" band of f-gen snow (1" to locally 2") stretches from about Jacksonville east to Paris and about 1 county north and south of this line. Again, this will be a wet snow and with ambient and ground temperatures above freezing for much of the event the majority of the snow will melt on contact with roadways. Exception would be in isolated more intense snow bands where visibility could briefly drop down to around 1/2 mile, a quick accumulation could occur especially on bridges/overpasses. Models show a trend down in cloud ice toward the end of the event, so maintained a 20-30% chance of light freezing rain for parts of east central to SE IL late tonight and early Monday morning, before precip exits or turns to rain. This is also expected to be non-impactful with only trace to 0.01" amounts forecast on elevated surfaces. For these reasons will leave the Special Weather Statement in effect for affected areas through tonight.

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LONG TERM

(Tuesday through Next Sunday) Issued at 236 PM CST Sun Mar 1 2026

A mid level trough will develop out west with southwesterly setting up over the area. This will lead to multiple waves of precip moving over the midwest through the entire week and into the weekend. Though there will likely be some breaks in the rain, The probability of rain looks to be 60-80% through Saturday with a 50-70% probability of seeing over 2 inches across most of the CWA. With this precip coming in multiple waves and the ground not being frozen, the rainfall should soak into the ground easily.

Isolated to scattered thunderstorms will also occur throughout the week, but stronger storms will be possible on Wednesday and again Friday as a couple of stronger waves and associated surface lows track into the region. While the exact track of the low and its associated strong/severe weather risk remains somewhat in question, a clear signal for convection is developing. While the models differ on the speed/timing of the systems, the atmosphere ahead of the lows is progged to be modestly unstable (SBCAPE 600-800J/kg) and strongly sheared (0-6km bulk shear 50-60kt), so the fuel for strong thunderstorms will be present. Current guidance suggest the strongest/severe storms will be southwest of the CWA both days. However, some machine learning guidance shows severe weather chances extending into part of central and south- central IL both days. Stay tuned for further details as the situation becomes clearer over the next couple of days.

Auten

AVIATION

(For the 06z TAFs through 06z Monday Night) Issued at 942 PM CST Sun Mar 1 2026

Light snow will overspread the SPI-DEC-CMI and possibly BMI terminals soon, and end prior to sunrise. MVFR ceilings are likely for the bulk of the event with IFR visibility in -SN. There will likely be a 1-3 hour period that visibility drops to LIFR in brief heavier snow bands near the I-72 corridor. After the snow ends, IFR ceilings should persist at KSPI-KDEC through much of the morning, with MVFR at KBMI-KCMI. The system is expected to stay south of KPIA, but it will be a close call with -SN and MVFR conditions likely just south of the terminal. Winds will be steady through the period, ENE/E at 10-12 kt.

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ILX WATCHES/WARNINGS/ADVISORIES

None.