FXUS63 KILX 152316 AFDILX Area Forecast Discussion...Updated Aviation National Weather Service Lincoln IL 616 PM CDT Sun Jun 15 2025 .KEY MESSAGES... - Severe weather risks return this week...with the most favored time period from Tuesday night through Wednesday night. - Typical mid-June temperatures will prevail...with a trend toward above normal readings in the 90s by next weekend. && .DISCUSSION... Issued at 211 PM CDT Sun Jun 15 2025 ...Weak System Passing South of Illinois on Monday... An upper low evident on 1830z/130pm water vapor imagery over southwestern Missouri will gradually shift eastward into the Ohio River Valley on Monday. Meanwhile a pair of short-wave troughs currently over eastern South Dakota and northeastern Iowa will track southeastward and weaken with time. As a result, the primary synoptic forcing for precip development will remain focused across the southern two-thirds of the KILX CWA late tonight through Monday evening. Based on latest HRRR/RAP, have opted to keep the forecast mostly dry for tonight...followed by just a 20% chance for showers south of I-70 toward dawn. As the low tracks eastward, scattered convection will develop...particularly during peak heating. CAMs generally keep highest areal coverage along/south of I-70 where 30-50 PoPs are warranted: however, cannot rule out a stray shower or storm further north across the rest of central Illinois during the afternoon. A few showers/storms will linger along/east of I-57 into Monday evening, followed by dry weather across the board Monday night. ...Potential MCS Tuesday night... As has been seen by the past several model runs, the weather will become more active by Tuesday night as MCS activity forms over the Plains, then spills eastward toward central Illinois overnight into Wednesday morning. 12z models generally have a good handle on the situation...focusing convection across southern Nebraska/northern Kansas late Tuesday afternoon. The nocturnal low-level jet is progged to strengthen considerably...with the NAM depicting a 50-60kt 850mb jet from Texas to northwest Missouri by 06z Wed. This will support an ongoing cluster of convection that will subsequently track E/SE into west-central Illinois late Tuesday night into Wednesday morning. Storms will likely be in a weakening mode as they arrive, but may still pose a gusty wind/heavy rainfall risk mainly along/west of I-55. ...Convective Re-Development Wednesday Afternoon/Evening... As is typically the case this time of year, the exact track of the overnight MCS will determine the evolution of convection later Wednesday. With no high-resolution guidance at that time frame, it is still too early to pin down specific details. Based on the synoptic pattern and the likely position of the morning storms, it seems reasonable to surmise the most likely location for storm re-development Wednesday afternoon and evening will be along/east of I-55. Given feed of rich Gulf moisture ahead of an approaching front, surface dewpoints in the lower to perhaps middle 70s will support SBCAPEs in excess of 2500J/kg where at least partial sunshine returns after the morning rain/clouds. In addition, NAM suggests 0-6km shear values increasing to 30-40kt in the warm sector. These parameters will likely support a broken line of strong to severe convection with an attendant strong wind/hail/tornado risk. ...Hot Weather by the End of the Week... Once the Wednesday system departs, a period of slightly cooler and drier conditions will be on tap for Thursday before upper heights rise and temperatures increase markedly. 12z NBM shows a high probability (60-80% chance) of exceeding 90 degrees across much of central Illinois next Saturday and Sunday. These temperatures combined with seasonally high dewpoints in the upper 60s and lower 70s may produce heat index values of 100 degrees or above. Barnes && .AVIATION... (For the 00z TAFs through 00z Monday Evening) Issued at 615 PM CDT Sun Jun 15 2025 A weak ridge will linger over the region resulting in light winds less than 10 kt through the period. Generally expect winds to be out of the NE this evening and slowly veer to a more southerly direction Monday, but light magnitude will result in some variability at times. MVFR ceilings in place earlier today have generally lifted/scattered to VFR and anticipate VFR to continue in the near term. Some patchy fog potential is possible overnight, but confidence is low in impacts at the terminals. MVFR ceilings will redevelop mid to late Monday morning from the south before lifting back to VFR by early to mid afternoon. Deubelbeiss && .ILX WATCHES/WARNINGS/ADVISORIES... None. && $$