918 FXUS63 KILX 132013 AFDILX Area Forecast Discussion National Weather Service Lincoln IL 313 PM CDT Tue May 13 2025 .KEY MESSAGES... - Scattered showers and thunderstorms will continue into early evening. Heavy rain and a few cold air funnel clouds are possible. - Near-record heat is forecast for Thursday. - A conditional threat of severe weather exists both Thursday and Friday. && .DISCUSSION... Issued at 313 PM CDT Tue May 13 2025 An upper-level closed low located near the Ohio Valley this afternoon has promoted widely scattered showers and storms over central Illinois once again today. Weak steering flow and SBCAPE values over 1000 J/kg have allowed some of these storms to quickly perk up while slowly moving northwest. PWATs with values over the 90th percentile of climatology (~1.3 inch) have allowed some of the strongest storms to produce rainfall rates of over 1" inch per hour. Because of this, a couple Flood Advisories have been issued where training thunderstorms have been slow to exit, especially in the Bloomington-Normal area. High resolution CAMs struggle to depict ongoing activity with coverage far lower than what is actually occurring. Would expect widespread showers and storms to continue through early evening with activity waning with the loss of daytime heating. Another thing to keep an eye out for is the development of cold-air funnel clouds. The Storm Prediction Center's mesoanalysis page shows pockets of values >1 which is indicative of favorable conditions for these to develop in. Upper ridging builds in over the central CONUS for the middle of the week as a Pacific Northwest trough swings into the northern Plains states. Temperatures by Wednesday will climb into the low to middle 80s with near-record warmth expected by Thursday as temperatures peak in the upper 80s to low 90s. High temperature records for Thursday range from 90-93 at our three climate sites (Lincoln, Springfield, and Peoria), with Peoria's record of 93 degrees being 131 years old. A conditional threat for severe thunderstorms still exists on both Thursday and Friday. Thursday's threat is a true boom or bust scenario with a few factors at play that could result in little or no storm development - a capping inversion, dry air entrainment in the lowest ~700 mb, the speed of frontal progression, and being displaced from the main upper wave. Despite this, a high moisture airmass will allow very strong instability to develop (2000-3000 J/kg of SBCAPE) and strong shear of 40-50 kts. If we are able to erode the CAP sooner than later, discrete supercell thunderstorms would be able to develop with all severe hazards possible. Another day of severe storms will be possible on Friday, mainly in southeast parts of the state as a cold front swings through. Guidance shows similar if not better parameters setting up over the southern half of the state by Friday afternoon. SPC's Day 4 15% convective outlook is just outside of our area at this time, but would expect to see at least a marginal risk added with the issuance of the Day 3 outlook overnight tonight. The upper trough will swing through the Great Lakes Region by this weekend as upper ridging spreads into the central US behind it. The first half of the weekend looks to be mostly dry with global models showing a shortwave trough rippling through somewhere near the Ohio Valley going into Sunday. The NBM continues to show low end chances of precipitation entering the area on Sunday with another larger trough sending a stronger system and more precipitation chances into the Upper Mississippi Valley by the start of the new week. NMA && .AVIATION... (For the 18z TAFs through 18z Wednesday Afternoon) Issued at 103 PM CDT Tue May 13 2025 Widely scattered showers and thunderstorms will be possible this afternoon into early evening, bringing occasional drops into MVFR or IFR ceilings/visibility. Activity should quickly dwindle with the loss of daytime heating by this evening. Light south-southeast winds will persist through the overnight hours with speeds picking up some by later Wednesday morning. Patchy fog continues to look like a possibility overnight with the focus being in east-central IL. Several high resolution models show visibility dropping down in the 4-6 mile range. NMA && .ILX WATCHES/WARNINGS/ADVISORIES... None. && $$