028 FXUS63 KILX 200517 AFDILX Area Forecast Discussion...Updated Aviation National Weather Service Lincoln IL 1217 AM CDT Sat Sep 20 2025 .KEY MESSAGES... - Daily chances for showers and thunderstorms are expected this weekend into the new week. Total precipitation will vary on where storms develop, with probabilistic guidance suggesting a 30-50% chance for total rainfall amounts over 2 inches. - Temperatures will stay warm through the weekend then cool closer to seasonal normals by the middle parts of next week. && .UPDATE... Issued at 847 PM CDT Fri Sep 19 2025 Made some minor adjustments to the pop/wx grids for the rest of the night and into tomorrow morning. Nothing major but did drop them below chance category. An updated zfp should come out with in the next 30 mins. Auten && .DISCUSSION... Issued at 231 PM CDT Fri Sep 19 2025 An upper trough spinning over the Northern Plains will slowly work into the Upper Mississippi Valley this weekend. Several embedded shortwaves will rotate through the main trough, bringing occasional chances for showers and thunderstorms through early next week. After a brief lull in activity the last few hours, an uptick in coverage has commenced this afternoon as a shortwave in eastern MO/southwest IL lifts northward. Latest high resolution guidance shows this activity pushing north of the area around or shortly after sunset this evening. Another uptick in coverage is expected late tonight after midnight with yet another shortwave. Although most should only see light rain during these periods, the 19.12Z HREF LPMM shows pockets of 24 hour QPF exceeding 1". Higher rainfall chances become focused north of the warning area on Saturday as shortwave activity shifts into northern Illinois. Precipitation chances increase once again Sunday into Monday (30- 60%) as several subtle shortwaves work through the upper flow. Although the entire weekend will not be a washout, the pattern warrants carrying at least low-end precipitation chances until the details can be refined. Weak shear through the weekend should keep the threat for any severe weather low. Temperatures will cool slightly each day, with highs by Sunday expected to peak in the upper 70s to middle 80s. Daily rainfall chances continue through the remainder of next week as a stronger upper low dives southeast into the central US, then becomes closed off near the middle Mississippi Valley. Upper ridging will be in place north of upper low, creating another Rex block over the central US. Central Illinois will be on the cooler, wetter side of this blocking pattern this time, which is a welcome sight as we attempt to ease our drought conditions. Little movement in the closed low will result in at least low-end chances for showers and storms through the end of next week. Probabilistic guidance has a 30- 50% chance of total QPF through the end of next week, which is an increase from previous runs. NMA && .AVIATION... (For the 06z TAFs through 06z Saturday Night) Issued at 1216 AM CDT Sat Sep 20 2025 A slow moving upper low will meander over the Upper Midwest through the forecast period with several bands of showers and storms expected in the vicinity of this feature. Have very low confidence in specific timing at the central Illinois terminals, but a few windows of showers and storms will be possible. Outside the influence of any precip, light winds and VFR conditions will prevail. Deubelbeiss && .ILX WATCHES/WARNINGS/ADVISORIES... None. && $$