FXUS63 KILX 271553 AFDILX Area Forecast Discussion...Updated National Weather Service Lincoln IL 1053 AM CDT Mon Oct 27 2025 .KEY MESSAGES... - There has been a slight trend southward in Wednesday's storm track, shifting the greater probabilities for beneficial rainfall more towards southern Illinois. Regardless of the storm track, Wednesday will become gusty (30-35 mph areawide). - Dry and seasonably cool weather will return by Halloween. && .UPDATE... Issued at 1045 AM CDT Mon Oct 27 2025 Updated the forecast earlier this morning to increase rain showers over southeast IL during this morning. Rain band has been diminishing and becoming more scattered and lighter in southeast IL past hour and HRRR has isolated showers lingering in southeast IL into mid afternoon. These showers caused by a 568 dm 500 mb low in nw TN and associated short wave, with upper level low tracking slowly eastward toward Nashville in mid TN by sunset. Broken to overcast 5-8k cloud decks south of I-72 at late morning while ample sunshine north of I-72. Expect clouds to increase northward toward I-74 during mid afternoon into early evening, with ne CWA seeing most sunshine today and mildest highs in the mid 60s. Highs in the lower 60s in southeast IL, closer to 60 in far southern CWA along highway 50 where clouds stick around. Breezy east to ENE winds 10-18 mph with gusts 20-25 mph adding a chill to the air over central IL, with winds a bit weaker in southeast IL. 07 && .DISCUSSION... Issued at 305 AM CDT Mon Oct 27 2025 This morning, water vapor imagery depicts a very chaotic upper- level pattern across the CONUS. Central Illinois is currently situated between an amplified ridge to the north and a closed low to the south. This synoptic pattern could be described as either a rex block or a split flow regime. Regardless, the entire system will shift eastward tonight as a strong shortwave trough carves into the Missouri Valley. Model guidance has come into more reasonable agreement on the evolution of this trough, with the disturbance becoming a closed low as it pushes into the Ozarks Tuesday night, then pivoting into the Tennessee Valley later Wednesday. Subtle variability remain regarding the depth and timing of this feature, and its attendant surface low. With respect to the GEFS and EPS, the low tracks are about 150 miles apart still, with the GEFS favoring a low track through Carbondale, IL, and the EPS favoring a track through Memphis, TN. This key discrepancy could be the difference between central Illinois being within the core of the beneficial rainfall axis (GEFS), or merely the periphery (EPS). After parsing through the 00z suite of ensemble guidance, there does seem to be a clear trend southward, positioning central Illinois on the periphery or gradient of the rainfall axis, while southern Illinois lies within the core of it. The GEFS and NBM are notable exceptions at this point, and you could argue these are now the outliers. We can see this bifurcation in the probabilistic guidance, too. Solution A (EPS, GEPS) exhibits a high (50-70%) probability of exceeding 0.5" south of a Macomb to Terre Haute line, while Solution B (GEFS, NBM) reveals similar probabilities but south of a Davenport to Champaign line. In other words, Solution A supports widespread beneficial rainfall across our CWA, while Solution B is more discriminatory, confining beneficial rainfall mostly across our southern CWA. The latest trends are favoring Solution B for now. Regardless of the exact track, surface winds will become breezy Tuesday night into Wednesday as low pressure rapidly deepens over the region. The 75th percentile of the NBM distribution seems like a decent hedge on gusts, which suggests something in the range of 30-35 mph. Needless to say, Wednesday will be a raw day. A ridge of high pressure will then establish itself Thursday and Friday, bringing dry and seasonably cool weather for Halloween. By the weekend, choppy mid-level flow is expected to return, ushering in another fast-moving frontal system across the region. MJA && .AVIATION... (For the 12z TAFs through 12z Tuesday Morning) Issued at 347 AM CDT Mon Oct 27 2025 Residual high pressure will linger over the regional terminals today, with occasional mid- and high-level clouds overspreading the area. Winds will remain from the east as a slow-moving frontal system passes to our south. While VFR conditions will persist through much of this TAF period, the probability of MVFR ceilings begins to creep toward KSPI and KDEC by 06z (30% chance), and particularly by 10z (50% chance). MJA && .ILX WATCHES/WARNINGS/ADVISORIES... None. && $$