240 FXUS63 KILX 241119 AFDILX Area Forecast Discussion National Weather Service Lincoln IL 619 AM CDT Tue Sep 24 2019 .SYNOPSIS... Issued at 400 AM CDT Tue Sep 24 2019 Weak high pressure over the lower Ohio river valley, will drift into the mid Atlantic states during tonight. This provides another nice day to central and southeast Illinois, with mostly sunny skies and increasing southwest breezes. After a seasonably cool start to the day, temperatures this afternoon will warm into the upper 70s to around 80 degrees. The dry weather will continue through this evening across the area, with a chance of showers and thunderstorms arriving after midnight into Wednesday, as a cold front moves through. Lows tonight will be in the upper 50s and lower 60s. Highs Wednesday are expected to be in the upper 70s to around 80 degrees. && .SHORT TERM...(Today through Wednesday night) ISSUED AT 400 AM CDT Tue Sep 24 2019 Weak 1017 mb high pressure was over the lower Ohio river valley/southern IL early this morning and providing fair skies with light to calm winds over our CWA. Some patches of clouds with bases of 4-5k ft were over northern IL, north of I-74. A refreshing airmass in place across the area, with seasonably cool temperatures mostly in the low to mid 50s, with Robinson down to 49F. High pressure will drift east across the Ohio river valley during today and into the mid Atlantic States during tonight. Nearby high pressure will provide mostly sunny skies today and will see increasing sw breezes by afternoon with gusts of 20 to 30 mph, strongest over nw/northern CWA. Nudged high temperatures up 1-2 degrees today into the upper 70s to around 80 degrees, with a fair amount of sunshine and dry airmass. A northern stream short wave tracks into the northern plains today and upper Midwest tonight, with surface low passing north of Lake Superior and driving a cold front se toward the IA/IL border by dawn Wed. Dry weather should continue through midnight across the CWA, then have isolated to scattered convection arriving during overnight, with pops of 20-40%, highest over the IL river valley. SPC day1 outlook has shifted the marginal risk nw of CWA for overnight. A slight to enhanced risk of severe storms tonight from western WI and se MN southwest thru much of IA into ne KS. A cold front to push se thru CWA during Wed and thru southeast IL Wed evening. Have isolated to scattered convection possible Wed morning across CWA and over southern 2/3rds CWA Wed afternoon and Wed evening and diminishing overnight Wed night in southeast IL. SPC day2 outlooks keeps marginal risk of severe storms sw of IL over southern central/sw MO, nw AR, sw KS and much of OK where better instability will be. Better forcing/lift it north/ne of IL on Wed. Highs Wed in the upper 70s to around 80F again, warmest over se IL. Will have breezy WNW winds behind the cold front by Wed afternoon especially from I-74 north. .LONG TERM...(Thursday through Tuesday) ISSUED AT 400 AM CDT Tue Sep 24 2019 Weak high pressure settles into the area on Thu bringing cooler and less humid air back into the area with a return of sunshine. Highs Thu in the low to mid 70s in central IL and mid to upper 70s in southeast IL. Another weather system moves east into the Midwest overnight Thu night and Friday returning chances of showers and thunderstorms to central IL, with highest pops over nw CWA. A cold front to push se into northern CWA by late Fri and linger over the area on Saturday before lifting back north by Sunday. Not in a day4 outlook, but nw CWA could see potential of stronger thunderstorms later Fri afternoon into Friday evening if enough instability develops ahead of the approaching cold front. Convection chances will continue to be higher over northern/nw CWA this weekend, while southeast IL should remain drier. Highs Friday range from upper 70s to around 80F northern CWA to mid 80s in southeast IL where just slight chance of convection there. More of a temp gradient on Sat with frontal boundary over area, with highs low to mid 70s nw CWA and low to mid 80s in southeast IL. A subtropical ridge is projected by medium/extended models to build northward into the mid MS river valley early next week and bring warm and more humid conditions to the CWA with highs in the 80s and lows in the mid 60s to near 70 degrees. Southeast IL has highs in the upper 80s to near 90F from Sunday through Tuesday. && .AVIATION...(For the 12Z TAFS through 12Z Wednesday morning) Issued at 619 AM CDT Tue Sep 24 2019 Expect VFR conditions for most of the upcoming 24 hour period, although low-level wind shear can be expected after 05-08Z as well as scattered showers and thunderstorms. Isolated MVFR conditions and gusty winds could occur with any thunderstorms, especially toward the end of the forecast period. Winds becoming S-SSW 5-10 kts this morning, increasing to 10-14 kts with gusts to around 20 kts by 18Z. Gusts decreasing by 00Z. && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...07 SHORT TERM...07 LONG TERM...07 AVIATION...37