Indianhead Mountain Resort Snow Report

173 FXUS63 KILX 100503 AFDILX Area Forecast Discussion National Weather Service Lincoln IL 1203 AM CDT Mon Aug 10 2026 .KEY MESSAGES... - Dangerous heat continues through Wednesday, with peak heat index values between 100 and 109 degrees daily. A Heat Advisory remains in effect through Monday along and south of a Canton to Casey line. Additional headlines may eventually be needed Tuesday and Wednesday. - Severe thunderstorms and heavy rainfall are possible overnight and again Monday night into Tuesday. The greatest risks with these storms will be damaging winds and localized flooding. && .UPDATE... Issued at 829 PM CDT Sun Aug 9 2026 A warm front was laid out west-to east near the I-80 corridor this evening. Scattered storms have recently developed in the vicinity of the front, as a 40 kt southwest LLJ has developed to our southwest, converging into northwest IL currently. CAMs show pretty good agreement of increasing storm coverage and intensity over the next several hours, mainly north of the I-74 corridor. Environment is highly unstable with MLCAPEs near 4000 J/kg, and deep layer shear is as high as 40 kt just to our north. This suggests supercells and multicell clusters, capable of frequent/vivid cloud to ground lightning, high rain rates up to 2"/hr, and isolated large hail and damaging wind gusts with the strongest updrafts. Storms should propagate to the east- southeast with time, eventually bringing the storm risk as far southeast as the Champaign/Vermilion counties later tonight. && .DISCUSSION... Issued at 107 PM CDT Sun Aug 9 2026 Synoptic Overview... The synoptic pattern remains dominated by a robust 595 dam upper-level ridge centered over the Four Corners, maintaining persistent northwesterly flow across the Great Lakes. Central Illinois resides on the periphery of this feature, effectively placing the region within the Ring of Fire near a quasi- stationary baroclinic zone. This configuration ensures hot, humid conditions and a challenging convective forecast, as models continue to struggle with the precise timing and evolution of successive nocturnal mesoscale convective systems (MCS). Short-Term Convective Potential... Regional radar imagery highlights an MCV from earlier upstream convection traversing southern Wisconsin, which is driving convective redevelopment over the Chicago metro area. Locally, capping (MLCIN > 100 J/kg) continues to suppress activity, though an outflow boundary currently moving across the Mississippi River north of Quincy remains a focal point for potential cap erosion this afternoon. If deep convection manages to initiate, effective shear profiles of 25-30 kt (per the latest RAP) are marginally sufficient for storm organization. Consequently, thunderstorm probabilities remain low (around 20%) north of I-72 through the early evening, but if storms do develop they could be strong. Overnight, the low-level jet (LLJ) is forecast to intensify, focusing moisture convergence along the instability gradient to our north. While the consensus of CAMs tracks the primary MCS activity across northern Illinois into Indiana, the orientation of Corfidi vectors from the northeast warrants caution. Should upstream development align favorably, there remains potential for propagation into central Illinois. Primary concerns with any nocturnal development would be locally heavy rain due to backbuilding and a damaging wind threat; trends will be monitored closely through the overnight hours. Heat and Instability: Monday - Wednesday... A persistent 850mb thermal ridge will dominate the Great Plains and Upper Midwest regions through mid-week, pushing temperatures into the 90s across western and southern counties of central Illinois. Sustained dew points in the mid-70s will result in peak heat indices ranging from 100 to 109 degrees daily. A Heat Advisory remains in effect for areas south of a Canton to Casey line for Monday. While additional headlines may be required Tuesday and Wednesday, uncertainty regarding the extent of convective debris and outflow boundaries currently precludes additional product issuance. The convective pattern remains highly repetitive for the first half of the week. Monday evening features an environment with very strong instability, with GFS-progged MLCAPE values approaching 4000 J/kg, supported by 25-35 kt of deep-layer shear. While the primary axis of moisture convergence will shift slightly south, Corfidi vectors again favor a southward propagation path into central Illinois. Similar conditions will be in place Tuesday and Tuesday night. Despite the persistent PoPs, it is important to emphasize that numerous dry hours will persist between convective waves. Extended Outlook: Thursday - Weekend... By the latter half of the week, western CONUS ridging will amplify, fostering deeper downstream troughing over the Great Lakes. This shift will place Central Illinois on the cooler side of the baroclinic zone, leading to a transition toward near- to slightly-below-normal temperatures. While the airmass will moderate, the LLJ will continue to provide sufficient forcing to maintain daily chances for showers and thunderstorms, particularly during the evening and overnight periods. && .AVIATION /06Z TAFS THROUGH 06Z TUESDAY/... Issued at 1203 AM CDT Mon Aug 10 2026 A cluster of thunderstorms is ongoing north of I-74 in northern Illinois late tonight. The latest suite of guidance suggests the majority of this activity will remain north of the terminals with a low chance (30%) that storms graze KBMI and KCMI through early Monday morning. Beyond that, shower and storm chances look to be relatively low through Monday, but confidence decreases by Monday night. South winds will veer to the southwest by late morning with gusts occasionally touching 20 kts. Winds will ease by Monday night and retreat to the south. && .ILX WATCHES/WARNINGS/ADVISORIES... Heat Advisory from noon today to 7 PM CDT this evening for Ilz051-040-041-047>052-061>063-066>068-071>073. && $$ KEY MESSAGES...Deubelbeiss UPDATE...25 DISCUSSION...Deubelbeiss AVIATION...NMA