550 FXUS63 KILX 121739 AFDILX Area Forecast Discussion National Weather Service Lincoln IL 1139 AM CST Tue Dec 12 2017 .UPDATE... Issued at 1029 AM CST Tue Dec 12 2017 Cold and breezy conditions will take place today behind yesterday's cold front. The breeziest areas will be east of I-55 as surface high pressure ridging and associated weaker pressure gradients are beginning to build into western IL and will spread east during the day. Mostly sunny conditions can be expected due to the high pressure, however a few cloud bands can be expected at times due to lingering cyclonic flow aloft. Cold advection will cause temperatures to rise only a few degrees from current temperatures, only reaching the mid to upper 20s along I-74 to the low 30s from Springfield to Lawrenceville southward. Have made minor updates for short term wind and cloud trends, but otherwise forecast is mainly on track for today. && .SHORT TERM...(Today and tonight) ISSUED AT 320 AM CST Tue Dec 12 2017 For the most part, not a lot of changes in this run. Northwesterly flow continues, bringing a series of shortwaves into the Midwest. The better chances for precipitation remain to the north and central Illinois gets some slight chances and flurries/sprinkles at best for most of the forecast. Cooler air moving into the region right now going to keep much of the area below freezing today. Teens and 20s filtering into central IL this morning will throw the diurnal trend off a bit, with some areas, particularly in the southern half of ILX forecast area, hitting their max temps for the day this morning. Not a lot of variation in the temps throughout the day. Blustery conditions this morning may ease a bit later, but winds to 15-20 mph will keep the wind chills in the single digits and low teens this morning... teens and low 20s this afternoon. Tonights lows will be in the teens and lower 20s...with winds easing a bit. .LONG TERM...(Wednesday through Monday) ISSUED AT 320 AM CST Tue Dec 12 2017 Next waves comes through the region on Wednesday and Friday, with deeper cold air moving into place Wednesday night through Friday. Wednesday will be slightly warmer than today until the reinforcing shot of cold air moves in. Front will bring slight chances for the northeast in the form of rain in the afternoon, ending quickly. Forecast gets another shot of cold air to wrap up the week, and a weak chance for precip again on Friday. Major systems not really in the model forecasts for Central IL. A bit of a pattern shift in the wake of Friday, with flow becoming almost zonal aloft as temps are allowed to warm a few degrees. A larger wave dives into the western half of the CONUS Friday, and at this point, the models diverge in the progression. Models vary between cutting off the system to the SW...and moving it through as an open wave. For now the forecast over the weekend is relatively mild temperature wise...and slight chances for precip on Sunday. However, confidence is low in the behavior of that wave after the pattern shift, as ensembles diverge quite a bit. && .AVIATION...(For the 18Z TAFS through 18Z Wednesday afternoon) Issued at 1139 AM CST Tue Dec 12 2017 High pressure moving into central IL will promote decreasing winds until around 06Z then another low approaching from the NW will bring increasing S-SW surface winds and winds aloft through the latter portions of the TAF forecast period. As a result of strong SW winds aloft have included low level wind shear from 10-15Z at KSPI-KBMI-KPIA due to 45 kt flow at 1500 ft AGL. Surface winds NW 12-17 kts with gusts over 20 kts through afternoon today, decreasing to light and variable for several hours from evening into early morning. S-SW winds then 10-12 kts by 12Z, increasing to 15-20 kts with gusts 25-30 kts by 18Z. && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...37 SHORT TERM...HJS LONG TERM...HJS AVIATION...37