333 FXUS63 KILX 060518 AFDILX Area Forecast Discussion National Weather Service Lincoln IL 1218 AM CDT Sat Jun 6 2026 .KEY MESSAGES... - Scattered thunderstorms are possible late tonight through Saturday. A few storms could have the potential to become strong to severe, posing a risk for heavy rain, large hail, and damaging winds. - Expect a warm and humid Saturday with feel-like temperatures climbing into the low 90s. - A stronger warming trend arrives Tuesday through Friday of next week, pushing heat index values near 100 degrees. && .DISCUSSION... Issued at 241 PM CDT Fri Jun 5 2026 Surface analysis this afternoon shows ridging centered over the southeast US with southwest return flow over a good portion of the Midwest states. A decaying line of showers moved through the area earlier today with some isolated activity developing in its wake over western and central Illinois this afternoon where moderately strong instability has developed. Despite this, little forcing should limit storm organization through early this evening. An approaching cold front and remnant outflow boundary will be the focus for thunderstorm development further west of here tonight as a shortwave trough and low-level jet provide large-scale ascent. The latest suite of CAMs suggest the thunderstorm activity will slide east into north-central Illinois late tonight after 1-2 am (mainly near/north of I-74). The 05.12Z HREF shows 1-2k J/kg of CAPE in place north of I-72 overnight, though the better shear is displaced well north of the forecast area. Despite this, a few storms may become strong overnight into Saturday morning and pose a threat for isolated large hail and damaging winds. More notably, heavy rain associated with thunderstorms could be the primary threat with forecast PWATs of 1.5 to 2 inches and warm cloud depths over 3k meters - favorable for high rainfall rates. The HREF's 24 hour precipitation LPMM shows pockets of 1-2" of rain near the I-74 corridor through Saturday morning with WPC highlighting a marginal risk for excessive rainfall in this same area. Surface ridging begins building in from the southwest on Saturday, turning things warmer and more humid for the weekend. Lingering cloud cover may suppress air temperatures some on Saturday, but are still forecast to climb into the middle 80s with dewpoints approaching 70 degrees by afternoon, leading to feel-like temperatures in the low 90s. The outflow boundary from overnight storms will linger over central Illinois on Saturday with CAMs suggesting storms regenerating along it by late afternoon/evening as SBCAPE approaches 2000 J/kg. However, weak shear and large scale subsidence should minimize storm organization. Hazards with any storms that do develop will be heavy rain and gusty winds as storms collapse. Upper ridging gets pushed east by Sunday as a closed upper low approaches from the west. Widespread cloud cover and increasing precipitation chances will hold temperatures closer to normal both Sunday and Monday. Upper ridging will build over the Plains states early next week pushing the upper low off to the northeast, resulting in a big warm up in temperatures by the middle to end of next week. Air temperatures look to climb into the upper 80s to low 90s Tuesday through Friday, with heat indices approaching 100 degrees. The LREF (ENS, GEFS, GEPS) shows a 20% chance for heat indices to exceed 100 degrees Wednesday through Friday. This paired with little relief in temperatures overnight could become dangerous, especially for those who have limited or no access to indoor cooling systems. && .AVIATION /06Z TAFS THROUGH 06Z SUNDAY/... Issued at 1218 AM CDT Sat Jun 6 2026 Main aviation concern will be with timing of any thunderstorm activity. At 05z, storms are mainly well into southern Iowa, though a few have begun percolating near the Mississippi River. Some overall uncertainty as to the timing and eastward extent of this activity, and will limit any PROB30 mention in the short term to KPIA/KBMI. The storms are expected to lay out a boundary that will serve as focus for renewed development from late morning into the afternoon, primarily from KPIA-KCMI. Additional storms are possible late in the period in this same corridor. Outside of the storms, VFR conditions are expected to prevail. && .ILX WATCHES/WARNINGS/ADVISORIES... None. && $$ KEY MESSAGES...NMA DISCUSSION...NMA AVIATION...Geelhart