574 FXUS63 KILX 301500 AFDILX Area Forecast Discussion National Weather Service Lincoln IL 1000 AM CDT Thu Sep 30 2021 .SYNOPSIS... Issued at 307 AM CDT Thu Sep 30 2021 Unseasonably warm weather will persist across central Illinois for the next couple of days...with afternoon high temperatures climbing into the 80s through Friday. The next significant chance for rain will hold off until the weekend. && .UPDATE... Issued at 1000 AM CDT Thu Sep 30 2021 Morning analysis indicated upper level ridge axis stretched south to north from the Gulf coast through the Great Lakes, across central IL. At the surface a low pressure trof extended north to south over the eastern Plains. Another unseasonably warm day is on tap with highs around 15 degrees above normal, mainly in the upper 80s. Aside from thin cirrus and scattered diurnal cu, mostly sunny skies expected. Southeast winds at 5-10 mph and dewpoints mixing down into the lower 60s will make for nice "July-August" weather. && .SHORT TERM...(Today and tonight) ISSUED AT 307 AM CDT Thu Sep 30 2021 A thick blanket of high clouds will stream across the area today, keeping temperatures a degree or two cooler than they were yesterday in the middle to upper 80s. Thanks to a continued dry easterly boundary layer flow, any showers that develop in advance of a short-wave trough over the Plains will remain west of the Mississippi River. Dry and mild weather will prevail tonight as lows drop into the lower to middle 60s. .LONG TERM...(Friday through Wednesday) ISSUED AT 307 AM CDT Thu Sep 30 2021 Blocking pattern will begin to break down on Friday, allowing short-wave energy to slowly approach from the west. Despite the change, the GFS continues to be too bullish driving showers eastward into the prevailing upper ridge axis. As a result, have cut rain chances considerably...with just low chance PoPs along/west of a Galesburg to Taylorville line in the afternoon. Given increased cloud cover, temps will be another degree or two cooler...with highs mainly in the middle 80s. As has been advertised the last several days, it appears a wet weekend is ahead. Scattered showers and thunderstorms will develop Saturday afternoon, then will become much more widespread Saturday night into Sunday as an upper trough currently over the Desert Southwest arrives. While instability will remain modest, upper dynamics will be favorable for thunder mention through the period. NAM/GFS precipitable water values increase into the 1.75 to 2.00 range Saturday night/Sunday, which is in the 99th percentile for early October. Given deep layer moisture and strong forcing, it appears central and southeast Illinois will see a significant rainfall this weekend...with the latest projections suggesting widespread amounts of 0.75 to 1.25. After the wave passes to the east, precip will taper off and come to an end Sunday night. Could potentially see a few showers re- develop Monday afternoon due to a secondary wave dropping through the region, but think that activity will be scattered at best. After that, cooler/drier weather will be on tap for Tuesday and Wednesday as highs drop back into the lower to middle 70s. && .AVIATION...(For the 12Z TAFS through 12Z Friday morning) Issued at 549 AM CDT Thu Sep 30 2021 VFR conditions will prevail through the entire 12z TAF period. NAM Cu-rule and forecast soundings suggest SCT Cu at around 5000ft from mid-morning through the afternoon. In addition, a thick layer of high clouds will persist through tonight. Winds will initially be calm early this morning, then will become E/SE at less than 10kt. && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...25 SYNOPSIS...Barnes SHORT TERM...Barnes LONG TERM...Barnes AVIATION...Barnes