076 FXUS63 KILX 050512 AFDILX Area Forecast Discussion National Weather Service Lincoln IL 1212 AM CDT Fri Jun 5 2026 .KEY MESSAGES... - A marginal risk for severe thunderstorms on deck for tomorrow, with isolated damaging wind gusts serving as the primary risk. - An unsettled weather pattern will bring daily chances of showers and thunderstorms through the middle of next week. - Humidity builds over central and southeast Illinois this weekend and lingers into next week, driving peak heat index values into the low to mid 90s. A nonzero (10- 20%) chance for heat indices above 100 degrees exists for late next week. && .DISCUSSION... Issued at 218 PM CDT Thu Jun 4 2026 The high pressure center drifted off to the southeast of central IL, shifting the flow to a more southerly direction today. This will support increasing moisture as we go into the weekend, starting today. Highs will increase to the upper 80s to low 90s, with dewpoints in the mid 60s to low 70s for Friday into Monday. Heat indices could bump north of 90 degrees by Saturday and looks to potentially continue into the new week. The LREF shows a nonzero (10- 20%) chance for apparent temps above 100 degrees late next week. In conclusion... summer has arrived. A shortwave will pulse through the region tomorrow, bringing rain chances into the forecast. The showers and thunderstorms tomorrow into Saturday could be efficient rain producers with PWATs around 1.7-2.0 inches. The convective complex moving in from Iowa will be decaying as it enters our western CWA. SPC has outlined a Marginal Risk (level 1/5) of severe weather north of a Mount Sterling to Gibson City line. The primary threat will be isolated damaging wind gusts as a pulse or multicell storm collapses. The higher rainfall amounts will be localized where multiple showers or thunderstorms pass over the same area during this time. Outside of convective activity, a tightening pressure gradient will cause southwesterly wind gusts to exceed 25 mph at times. There does appear to be the possibility of a few more weak rounds of convection into Wednesday. The timing and rainfall amount forecast remains uncertain at this time, due to weak forcing. A cutoff upper- level low or slow-moving trough is forecast to develop and linger around the Midwest, while a weak frontal boundary drifts around the area. The extended forecast relies heavily on the NBM due to that uncertainty. Looking beyond the seven-day window, the CPC 6-10 day outlook highlights a strong signal for a persistence of above-normal temperatures across the central U.S. && .AVIATION /06Z TAFS THROUGH 06Z SATURDAY/... Issued at 1212 AM CDT Fri Jun 5 2026 Area of showers/storms currently extending from near Kansas City to southwest Wisconsin is expected to lose some of its punch before reaching central Illinois. Currently projecting the 15-18z time frame for it to pass the terminals, though a PROB30 group for some thunder at KPIA/KSPI will remain in the new TAF set. Toward the end of the period, the evening model guidance is suggesting a west-east line of convection developing in northern or central Illinois. Thinking that most of this threat will be after 06z, but will include a PROB30 at KPIA for the last couple hours. South winds are expected to pick up overnight, and gusts 20-25 knots should be common by mid morning as winds trend more southwest. The gusts are expected to drop off after 00z, though sustained winds 10-15 knots are still likely in eastern Illinois through Friday evening. && .ILX WATCHES/WARNINGS/ADVISORIES... None. && $$ KEY MESSAGES...Copple DISCUSSION...Copple AVIATION...Geelhart