textproduct: Central Illinois

KEY MESSAGES

- Dry Frontal Passage Tuesday: Milder conditions are expected Tuesday ahead of a front with highs in the low to mid 50s. No precipitation is expected with the frontal system.

- Low Snow Potential Thursday: There is a low (5% to 20%) chance for light snow Thursday evening, primarily north of a line from Canton to Decatur to Robinson.

- Weekend Rain Chances: A stronger weather system is forecast to bring rain to the region Saturday into Sunday. While there is an 80% chance of rain, uncertainty remains regarding the exact track and the potential for any thunderstorms.

DISCUSSION

Issued at 102 PM CST Mon Feb 9 2026

Short Term (Tonight through Tuesday)... High pressure currently situated along the East Coast will gradually give way as an area of low pressure digs southeast across Ontario. This pattern favors mid-level warm air advection across much of Central Illinois through tonight. Specifically, an 850mb thermal ridge, with temperatures peaking between 12-14C, will center over the region tonight. Coupled with a modest southwest surface breeze, this setup will inhibit strong radiational cooling, leading to steady or slightly rising temperatures overnight.

Tuesday will feature a modest warm-up, with daytime highs expected to push into the low to mid-50s across most of the CWA. This milder weather, however, will be short-lived as a cold front advances through the region during the day. Moisture remains extremely shallow along the front, with Precipitable Water (PWat) values only ranging from 0.5 to 0.7 inches. Consequently, the frontal passage is forecast to be a dry one, with no measurable precipitation expected. Moderate northwest winds will set up behind the front with gusts topping out in the 25 to 30 mph range.

Late-Week (Wednesday through Friday)... Following the departure of the Tuesday weather system, the upper- level flow will transition back to a northwest flow regime with troughing across the eastern half of the CONUS, a pattern that is expected to persist through the latter half of the work week. A general west-to-east temperature gradient will be established across Central Illinois, with the coldest temperatures just off to our east. This will result in a period of slightly above-normal temperatures, with afternoon highs generally running in the low to mid-40s from Wednesday through the weekend.

The main focus during this period is a damping shortwave trough set to drop from the northern Great Plains Wednesday night, clipping northern Illinois on Thursday evening. Considerable uncertainty remains regarding the finer details of this system, including its exact track, precipitation type, and accumulation potential. The latest guidance continues to diminish the likelihood of accumulating snow. The National Blend of Models (NBM) currently suggests the probability for an inch of snow is low (5-20%) along and north of a Canton to Decatur to Robinson line, with the highest probabilities (15-20%) confined north of I-74. Furthermore, the precipitation type probabilities are split evenly for rain and snow along the aforementioned Canton to Robinson line, with snow becoming favored north and rain to the south. Given the uncertainty and low probabilities, confidence in an impactful event remains low.

Long Term (Weekend)... Attention then turns to a strong shortwave trough forecast to dig across Southern California and Baja on Thursday night. This feature is modeled to lift across the lower and mid-Mississippi Valley Saturday night. In response to this upper-level energy, a surface low will develop and deepen, tracking across or near the region this weekend. While models show good agreement on the overall evolution of this system, significant differences persist regarding the low's precise track and speed.

At this time, any precipitation across Central Illinois is favored to be primarily rain. The past couple of runs of the GFS model have been trending southward, keeping the bulk of the precipitation shield south of our CWA. However, a low but non-zero threat for thunderstorms exists, particularly if a northerly track solution from models like the GemNH verifies, allowing a narrow warm sector to briefly impinge on portions of Central Illinois. Better model consensus is needed before higher confidence can be established for the weekend forecast.

Deubelbeiss

AVIATION

(For the 00z TAFs through 00z Tuesday Evening) Issued at 549 PM CST Mon Feb 9 2026

VFR conditions are expected over the next 24 hours, however a dry frontal passage will take place Tuesday morning, which will bring a shift in winds and possibly some brief low cloud cover. Overnight a low level jet around 45 kts from the SW will bring low level wind shear from around 04Z-06Z until 12Z-14Z. Surface winds S 8-10 kts overnight, shifting to NW by 15Z and increasing to 12-15 kts with gusts over 20 kts.

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ILX WATCHES/WARNINGS/ADVISORIES

None.