Area Forecast Discussion
Issued by NWS Central Illinois
Issued by NWS Central Illinois
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017 FXUS63 KILX 232316 AFDILX Area Forecast Discussion...Updated Aviation National Weather Service Lincoln IL 616 PM CDT Mon Sep 23 2024 .KEY MESSAGES... - Widespread showers and a few thunderstorms will continue tonight, lingering into Tuesday. Additional rainfall looks to be around an inch near I-72, with the remainder of the area likely to receive over a half inch. Some locally higher amounts are possible, with some spotty precipitation amounts exceeding 2 inches possible. - Additional rainfall is possible starting Thursday as moisture associated with a developing tropical storm system from the Gulf of Mexico moves into the region. && .DISCUSSION... Issued at 325 PM CDT Mon Sep 23 2024 A surface low is situated in southern MO this afternoon, with warm front extending east of the low into the Ohio Valley. As the low moves northeastward overnight, the warm front should clip southeast portions of the ILX forecast area with an increasingly moist and unstable air mass, resulting in several hundred J/kg MUCAPE, which looks to remain elevated. This should bring a period of scattered thunderstorms this evening and overnight to around the I-72 corridor, with some isolated lightning activity to the north. 12Z HREF depicts the highest CAPE around 750 J/kg south of I-70 where the strongest storms could be expected, but likely below severe limits. SPC continues a Marginal Risk just south of Clay, Richland, and Lawrence counties for a large hail and locally damaging wind risk, as well as a potential tornado or two. After this last wave moves through overnight, producing widespread rain of a half inch to inch, with locally over 2 inches depicted by HREF ensembles, showers and thunderstorms should taper off from west to east during the daytime Tuesday, although a few showers could continue into the afternoon as an upper level trough digs southward over the region and begins to cut off. Wednesday should be dry as the upper low continues to dig southward to near Arkansas vicinity, meanwhile NHC estimates a tropical disturbance will have strengthened to Hurricane Helene in the Gulf of Mexico. The forecast track currently moves through the FL Panhandle into GA, then potentially hooks back westward due to influence by the cutoff low, weakening to a depression heading toward IL. While considerable uncertainty remains in this yet to develop tropical storm track, the main message is that at least associated moisture appears likely to circulate back toward IL late this week through the weekend into early next week, for additional rain chances in central IL. Doesn`t appear to be a high likelihood of excessive rainfall as the Appalachians will likely remove a significant amount of moisture, but several days of rain chances could prove to bring beneficial moisture to central IL. Temperatures should continue to be cool Tuesday with the lingering showers and cloud cover, with highs ranging from around 70 in most of central IL to mid 70s south of I-70, then as the fairly stagnant pattern develops with the cut off low to our south/southwest, we should see highs around the mid 70s for several days. 37 && .AVIATION... (For the 00z TAFs through 00z Tuesday Evening) Issued at 615 PM CDT Mon Sep 23 2024 An area of low pressure currently over south central Missouri will lift across central Illinois late this evening and overnight bringing scattered showers and a few isolated storms along with IFR or lower conditions. As the low center passes south of the terminals, NE winds currently in place will become light and variable or gradually back to the NNW by midday Tuesday. As NW winds overspread the area through the day, expect ceilings to gradually lift to MVFR then VFR with precip coverage gradually tapering off. Deubelbeiss && .ILX WATCHES/WARNINGS/ADVISORIES... None. && $$