Area Forecast Discussion
Issued by NWS Central Illinois
Issued by NWS Central Illinois
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488 FXUS63 KILX 181024 AFDILX Area Forecast Discussion...Updated Aviation National Weather Service Lincoln IL 524 AM CDT Wed Sep 18 2024 .KEY MESSAGES... - Summer-like warmth continues through the first half of the weekend with daytime highs in the middle 80s to near 90. - A more unsettled pattern arrives late this week into early next week as a few frontal systems bring periodic chances for showers and storms. && .DISCUSSION... Issued at 247 AM CDT Wed Sep 18 2024 A rex block remains in place over the eastern CONUS with upper ridging over the northeast US and an upper low over the southeast CONUS. An upper trough over the western CONUS will act to break down the rex block as a few shortwaves embedded lift through the Plains states. Our weather will remain largely unchanged the next few days with high temperatures through the first half of the weekend topping out in the middle 80s to near 90 degrees. Lower dewpoints from daytime mixing will keep overnight lows near seasonable normals this morning and again tonight, with readings as of 2 am sitting in the 50s. Our extended period of dry weather will be replaced by a more unsettled pattern later this week into the start of the new week as the aforementioned upper waves send frontal systems through the area. The first wave will bring a cold front into western parts of the area Thursday night into Friday morning, stalling out over central Illinois on Friday. Most precipitation from this wave will be near/west of I-55 through Friday morning, however some isolated activity may develop Friday afternoon along the slow moving front as diurnal heating kicks in. By this point in time though the parent wave will be pretty far north of the area suggesting low-level moisture will be rather limited. The NBM came in with a mostly dry forecast Friday afternoon, so left that untouched for now. Better chances for showers and storms arrive this weekend into early next week as a stronger upper wave lifts into the Upper Mississippi Valley along the western periphery of the upper ridge. A strong push of WAA along the system`s warm front will increase precipitation chances across the area later Saturday into Sunday, with the cold front following behind it early next week. QPF amounts over the next 7 days still looks to be beneficial, especially west of I-55 where LREF probabilities show a 30-50% chance of amounts exceeding 1 inch. Occasional thunderstorms may bring locally higher amounts at times. Temperatures will be cooler to start the week with upper troughing dives through the Midwest states. Longer range guidance suggests upper ridging building in behind that, which would imply another warm up. This falls in line with the Climate Prediction Center`s 8- 14 day outlook (Sep 25 to Oct 1) which favors warmer than normal temperatures. NMA && .AVIATION... (For the 12z TAFs through 12z Thursday Morning) Issued at 524 AM CDT Wed Sep 18 2024 VFR conditions prevail. Winds will be light and variable with some high cirrus passing through tonight. NMA && .ILX WATCHES/WARNINGS/ADVISORIES... None. && $$