textproduct: Central Illinois

KEY MESSAGES

- A developing storm on Saturday could bring heavy rain south of I-70. The current forecast supports a medium (40-60%) chance of exceeding 0.25 inches of rain near and south of I-70. Further north, totals may be significantly lower.

- Unseasonably warm air (20-25 degrees above normal) arrives next week, peaking Wednesday with mid-60s to lower 70s temperatures. Expect gusty southwest winds to accompany this warmup.

DISCUSSION

Issued at 1153 AM CST Wed Feb 11 2026

Unseasonably warm and dry conditions will persist through Friday, as surface high-pressure slowly tracks across the Midwest, positioned downstream of an anomalous 500-mb ridge. Daily average temperatures are expected to be 10-15 degrees above the typical mid-February norms for the remainder of the week.

The upstream ridge is forecast to weaken Friday night as a vigorous shortwave trough moves across Baja California. The acceleration of this feature across the Lower-Mississippi Valley on Saturday will cause a surface low pressure system to deepen and broaden, drawing up moisture from the Gulf. Central Illinois will be situated on the northern edge of this developing low, resulting in uncertainty regarding the sharpness and northward extent of the low-level baroclinic zone, associated frontogenesis (FGEN), and subsequent precipitation. Ensemble guidance varies: the GEFS and EPS mean depicts approximately 0.25 inches of precipitation as far north as the I-70 corridor, while the wetter GEPS supports closer to 1 inch. Probabilistically, the latest 13z NBM indicates a medium (40-60%) chance of precipitation exceeding 0.25 inches near I-70, with probabilities sharply decreasing further north.

Drier weather will return on Sunday across the Plains and Midwest as surface high pressure settles in behind the departing storm system. An aggressive warm-up is then anticipated through the middle of next week. This pattern will be driven by a deep trough digging into the eastern Pacific, which will spread deep southwest flow across the intermountain west and the Plains states. As this trough moves eastward and a surface lee cyclone strengthens, the Midwest will experience gusty southwest winds. The net effect will be the warmest temperatures of the season so far. Current NBM median guidance supports mid-to-upper 60s by Tuesday and Wednesday, with the upper tail of guidance pushing lower 70s.

MJA

AVIATION

(For the 00z TAFs through 00z Thursday Evening) Issued at 502 PM CST Wed Feb 11 2026

A high pressure ridge will cross the region tonight, bringing light and variable winds. A weak upper level disturbance tracking in from the northwest will increase high clouds overnight, with BKN mid level (VFR) deck expected to persist through Thursday afternoon.

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ILX WATCHES/WARNINGS/ADVISORIES

None.