textproduct: Central Illinois

KEY MESSAGES

- Temperatures remain seasonably cold through tomorrow. Tonight will be the coldest, with a 60-80% chance for wind chills lower than 10 degrees below zero.

- This evening, lake effect snow showers may impact areas north of a roughly Macomb to Paris line. While accumulations would be light, visibility reductions and slick patches on roads may accompany those showers.

- There is a 30-40% chance for light accumulating snow on Sunday, with amounts generally staying under an inch. Locally slick roadways would be the main impact.

- A corridor of accumulating snow may impact a portion of central or southeast Illinois Tuesday into Wednesday, but confidence is low on precisely where. At this time, there is a 20-40% chance for more than one inch of accumulation area-wide.

DISCUSSION

Issued at 133 PM CST Fri Jan 30 2026

***** FEW SNOW SHOWERS THIS EVENING? *****

At 130pm, a potent east to west-oriented shortwave trough was moving south across the Midwest, bringing 850mb temperatures into the -20s degC across Iowa. Steep low level lapse rates developing off the relatively warm waters of Lake Michigan have already resulted in moderate to heavy snow showers impacting parts of the Chicago Metro, and even some light snow as far south as LaSalle/Peru. Low level flow will turn to northeasterly behind the trough axis slated to swing through our area this evening, potentially advecting some of that lake induced instability into our neck of the woods, though it will become modified by our resident dry airmass. While CAMs have backed off slightly on the potential for snow, HREF and REFS probs remain around 20-40% for measurable snow north of a roughly Pittsfield to Champaign line. If there are impacts, they would come in the form of briefly reduced visibilities and slick roadways. Remember to take it slow if you encounter snow.

***** ARCTIC CHILL CONTINUES *****

With 1043-1045mb surface high pressure sinking southward across the eastern Plains, the gradient will tighten tonight giving us 10-20mph winds which, with temperatures in the single digits, will result in wind chills 10 to 15 degrees below 0. Though we'll be flirting with Cold Weather Advisory criteria, we've no plans to issue on this shift given we've had our share of worse cold throughout the past couple weeks. In addition to the cold, we may see some lake effect flurries or even snow showers spill into Vermilion, Edgar, or Champaign Counties overnight tonight into tomorrow, though the PWAT of 0.08" from our morning sounding suggests there's a lot of dry air which will be difficult to overcome.

***** LIGHT SNOW SUNDAY, WINTRY PRECIP TUESDAY *****

As ridging over the western contiguous U.S. expands slowly eastward, temperatures are forecast to moderate across the Midwest, though this will come at the cost of the storm track entering our area once again. Disturbance 1 will feature isentropic upglide ahead of a shortwave mid-level trough, resulting in light snow Sunday afternoon and evening. Accumulations are looking light, with LREF/NBM probabilities for more than 1 inch generally around 10-25% (highest west of I-55), though we still anticipate some slick roadways given the cold ground. Disturbance 2 is a clipper slated to pass through or near our area on Tuesday. Confidence is considerably lower with this one, but with the 0 degC 850mb temperature line near or over central IL it'll bear watching for mixed precipitation. Thermodynamic profiles suggest freezing rain, snow, and/or rain would each be plausible, depending on the track and strength of warm advection with this system. Depending on how much of our 7-12 inch frost depth can thaw by that time, even rain may freeze on contact with the ground to create slick spots. QPF isn't looking overly impressive, so if we do wind up on the cool north side of the low and have snow as the dominant p-type, accumulations would be under 3 inches for most. Of course, there's still around a 30% chance this feature misses us entirely. Our next chance for precip will then be towards the end of next work week, when the deterministic GFS and ECWMF suggest a larger upper level trough will dig south across the Great Lakes, potentially bringing another shot of blustery, cold, and snowy weather.

Bumgardner

AVIATION

(For the 18z TAFs through 18z Saturday Afternoon) Issued at 1143 AM CST Fri Jan 30 2026

Lake effect snow showers have moved ashore and are resulting in IFR visibilities at times in the Chicago area. Those are slated to shift southeast toward I-74 this evening, potentially (30% chance) impacting the I-74 airfields from 00-04z and SPI a couple hours later. Winds behind this wave will shift from northerly to northwesterly, remaining sustained at 9-12kt. Some guidance is hinting at MVFR ceilings materializing at the end of the forecast period, but given low (30%) confidence we only hinted at the potential with SCT025.

Bumgardner

ILX WATCHES/WARNINGS/ADVISORIES

None.