textproduct: Central Illinois

KEY MESSAGES

- Rain will persist and move northward today. The heaviest rain axis remains south of I-70, where ponding may occur, especially in low-lying, poorly drained, and urban areas.

- Unseasonably warm air (20-25 degrees above normal) arrives next week, peaking Wednesday and Thursday with mid-to-upper 60s temperatures. Gusty southwest winds (30-40 mph) will precede this warmup.

- A conditional threat for severe weather exists but is not particularly likely in the Wednesday-Thursday timeframe.

UPDATE

Issued at 858 PM CST Sat Feb 14 2026

Water vapor imagery late this evening shows a potent shortwave trough over the southern Plains states with a surface low working through the lower Mississippi Valley region. Isentropic ascent on the northern fringes of this low has resulted in widespread light to moderate rain over the southern half of the state. A sharp cutoff in precipitation has remained rather stationary over the last few hours roughly along a Macomb to Danville line. Rain has occurred for most south of this line with the highest amounts coming in south of I-72 where radar estimates and automated surface observing stations show anywhere from 0.25-0.75" have fallen. Additional amounts through tonight look to top out around 0.50", though values higher than that are not out of the question especially near and south of I-70 where frontogenetic banding is favored.

Rain exits from northwest to southeast after midnight, with the potential for fog to develop as winds remain light. High resolution guidance continues to suggest the best chances for patchy fog will be north of the I-70 corridor after 3 am, just north of the departing rain shield. The 15.00Z HREF shows about a 20-40% chance for visibility to fall below 1 mile so confidence is still rather low on if widespread dense fog will materialize.

NMA

DISCUSSION

Issued at 1220 PM CST Sat Feb 14 2026

A vigorous shortwave trough continues to push toward the Lower- Mississippi Valley this afternoon, causing 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. High-res guidance continues to show notable run-to-run variability. Specifically, the RRFS model has oscillated the QPF gradient north-or-south 50 miles over its last 3 iterations (00z, 06z, 12z). Meanwhile, the HREF has been more consistent with its depiction of the QPF gradient, which is focused west-to-east along I-72/HWY-36.

Probabilistically, the likelihood of heavier rain remains south of I-72/HWY-36. The latest 12z HREF indicates a high (70-90%) chance of rainfall exceeding 0.50 inches south of a Pittsfield to Paris line, with probabilities dropping sharply to the north. Furthermore, a medium (40-60%) chance of exceeding 1 inch of rain is forecast south of an Effingham to Robinson line.

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 (30-40 mph). The net effect will be the warmest temperatures of the season so far. Current NBM median guidance supports 60s Monday through Thursday, with the upper tail of guidance pushing 70 degrees for Wednesday and Thursday.

The main concern for the middle of next week is the potential for severe weather. Despite strong atmospheric dynamics and excellent forcing mechanisms for lift, global deterministic models are currently struggling to clearly show a convective signal. For the time being, it appears models are either slow to bring in low- level moisture, or the conditions will genuinely be too dry to support organized convection with the cold front passing early Wednesday. A potentially better signal emerges for Thursday evening, tied to another shortwave trough pivoting through the Upper- to Mid-Mississippi Valley region. However, moisture and instability profiles in deterministic guidance are not particularly promising for this period either, at least at the current time.

A shift to cooler weather is expected to return and persist from Friday through next weekend. The NBM deterministic guidance suggests daily temperatures will remain slightly above normal, with afternoon high temperatures around the lower 40s and overnight lows in the upper 20s.

MJA

AVIATION

(For the 06z TAFs through 06z Sunday Night) Issued at 1148 PM CST Sat Feb 14 2026

Rain associated with a low pressure system passing by well to the south of central IL will continue along the I-72 terminals KSPI- KDEC-KCMI the first few hours after 06Z, gradually departing the area. Behind the rain, IFR cigs and possibly IFR or worse visibility in fog will develop, and continue into the morning hours. Expecting VFR conditions to develop by around 16Z-17Z.

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ILX WATCHES/WARNINGS/ADVISORIES

None.