339 FXUS63 KILX 060917 AFDILX Area Forecast Discussion National Weather Service Lincoln IL 417 AM CDT Mon Sep 6 2021 .SYNOPSIS... Issued at 330 AM CDT Mon Sep 6 2021 Dry weather continues across much of the region on this Labor Day with a fair amount of sunshine again and highs in the low to mid 80s. The next chance of showers and thunderstorms comes Tuesday afternoon and evening, as the next frontal system moves through the Great Lakes. Warm highs in the upper 80s Tuesday with breezy southwest winds. Temperatures then fall back into the upper 70s and low 80s through the end of this week. && .SHORT TERM...(Today and tonight) ISSUED AT 345 AM CDT Mon Sep 6 2021 Another nice day expected on this Labor Day over central and SE IL, as 2 of the 3 days of this holiday weekend enjoying a fair amount of sunshine (yesterday and today). Patchy shallow fog in southeast IL should lift by mid morning. Otherwise mostly sunny skies overall today as few- scattered cumulus clouds develop by late morning and afternoon. Also have scattered mid level clouds with bases 8-10k ft moving se into central IL near I-55 early this morning ahead of a weak cold front over northern IL that pushes south toward far northern CWA by early afternoon and to near I-74 late this afternoon. Highs in the low to mid 80s today, and dewpoints elevating into the low to mid 60s. IL remained in a nw upper level flow aloft with a strong 595 dm 500 mb high over NV and central CA and upper level trof over the central Great Lakes into the OH/TN river valleys. A few CAMs show some light rain showers developing along I-74 by 21Z/4 pm but feel sprinkles at best as little lift and have a capping inversion. The weak front to start lifting back north as a warm front tonight, lifting north of CWA by overnight. A bit milder tonight with SSW winds, with lows in the low to mid 60s, coolest near the IN border. A narrow band of moderate instability along and ahead of the cold front with CAPES reaching around 2000 j/kg per GFS model and much higher per NAM model which has higher dewpoints. The 0-6 km bulk wind shear values rise to 35-50 kts by late Tue afternoon. SPC day2 keeps marginal risk of severe storms ne of CWA for Tue afternoon/evening with damaging winds main threat. We have some capping to overcome and will need to watch closely for northern CWA late Tue afternoon and early Tue evening. Breezy sw winds on Tue to gust 25-30 mph and warmer highs in the upper 80s along with dewpoints in the mid to upper 60s. Chances of showers/thunderstorms to shift se of CWA after 1 am Tue night with cold frontal passage. Lows Tue night range from mid 50s northern/nw CWA to lower 60s south of I-70. Cold front pushes se of the Ohio river on Wed with upper level trof digging into the Great Lakes and Oh/TN river valleys. A fair amount of sunshine Wed over central/se IL with breezy nw winds bringing in cooler and less humid air. Highs Wed in the upper 70s in central IL and lower 80s in southeast IL. Cool lows Wed night in the low to mid 50s. Weak 1020 mb high pressure to drift east over IL by sunset Thu with lighter winds Thu and a fair amount of sunshine again. Highs Thu in the upper 70s over much of the CWA with Lawrenceville near 80F. Lows Thu night mostly in the mid 50s. Slight modification in temps Fri with highs in the lower 80s and humidity levels staying fairly comfortable as weak high pressure drifts east of IL. The strong 500 mb high pressure over the Desert SW will start to build back closer to central IL this weekend (500 mb heights rise to 588-591 dm Sat afternoon into Sunday), with storm track being north of IL, as another storm system passes north of the Great Lakes on Sat. Temperatures to return to more summer like readings during this weekend, highs in the low to mid 80s Sat and upper 80s by next Monday. && .LONG TERM...(Tuesday through Sunday) ISSUED AT 410 AM CDT Mon Sep 6 2021 A northern stream short wave/trof over the southern Canadian Rockies to develop a fairly strong surface low pressure about 997 mb just north of Lake Superior by 18Z/1 pm Tue and push a cold front into far nw IL then. Latest forecast models have trended slower with cold front pushing se to between the IL river and I-55 by sunset Tue, and pushing into southeast IL around 06Z/1 am Tue night. && .AVIATION...(For the 06Z TAFS through 06Z Monday night) Issued at 1127 PM CDT Sun Sep 5 2021 VFR conditions expected the next 24 hours, with main aviation concern being the winds. Light southwest winds expected to turn west between 12-15Z, and increase to 8-10 knots from KSPI-KCMI. Winds diminish and swing back to the south early evening. && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...07 SHORT TERM...07 LONG TERM...07 AVIATION...Geelhart