


Area Forecast Discussion
Issued by NWS Central Illinois
Issued by NWS Central Illinois
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212 FXUS63 KILX 101111 AFDILX Area Forecast Discussion...Updated Aviation National Weather Service Lincoln IL 611 AM CDT Thu Jul 10 2025 .KEY MESSAGES... - There is a 20-30% chance of showers and thunderstorms today and Friday, mainly during the afternoon and evening hours and highest pops over the IL river valley/nw CWA. There is a marginal to slight risk of severe storms over central IL late Fri afternoon and Fri evening. There is a 50-60% chance of showers and thunderstorms Saturday and some storms could be strong Saturday afternoon with gusty winds and locally heavy rains. - Very warm and humid conditions will continue through at least Saturday, with Friday being the hottest today with highs in the lower 90s, and heat indices in the upper 90s to around 100 Friday afternoon. && .DISCUSSION... Issued at 255 AM CDT Thu Jul 10 2025 Predawn surface map shows a frontal boundary from nw Ohio and northern Indiana (near Fort Wayne and La Fayette IN) and westward over central IL, south of BMI and PIA and north of Macomb. The front then turned into a warm front over central Iowa. Radar mosaic shows a small area of moderate rain showers moving se into nw Christian county that had developed over central Mason county a few hours ago. GOES 19 IR and Nighttime Microphysics Satellite imagery`s show patches of clouds over central IL west of I-57 while clear skies in eastern IL from I-57 east. Patchy fog noted ne of I-74 and more widespread and denser fog in northeast IL and Indiana with Pontiac vsby less than 1/4 mile. Lacon and Rantoul airports vsbys were 3 miles. Fog due to light to calm winds and moist boundary layer. Latest CAMs show patchy fog developing over central and eastern IL next few hours and becoming locally dense in spots. There is a dense fog advisory until 9 am from Livingston, Ford and Iroquois counties and will monitor our eastern/ne counties for that possibility or a special weather statement. The shallow fog should lift between 8-9 am. MCS/MCV over western parts of MN and Iowa and eastern Nebraska to weaken during this morning as it tracks eastward toward nw IL by early afternoon. Outflow boundary from this system to likely develop broken band of convection along it during midday/early afternoon as air mass get more unstable with daytime heating, with MLCAPES rising to 1-2k J/kg over portions of central and nw IL and Bulk Shear values increasing to 20-30 kts over west central and nw IL by late afternoon. SPC Day1 outlook keeps marginal risk of severe storms nw of Knox and Stark counties but will need to watch for risk of stronger storms later today. Marginal risk is over far nw IL for gusty winds, hail and isolated tornadoes nw of Quad Cities to Rockford line from mid afternoon into mid evening. Locally heavy rains possible too over far northern CWA per HREF LPMM having pockets of 1-4 inches north of Galesburg to Lacon line. We have slight chance of convection over central and southeast CWA this afternoon/evening with 30-40% northern CWA from Quincy to BMI north. Highs today in the upper 80s to near 90F with afternoon heat indices peaking in the low to mid 90s. A stronger short wave trof to dig southeast from the upper Midwest/northern plains into Iowa Fri evening and to bring more chances of convection to area Fri afternoon/night especially over IL river valley. SPC Day2 has marginal risk of severe storms nw of I-70 with slight risk nw of IL river late Fri afternoon and Fri evening for damaging winds, large hail (IL river valley) and 2% risk of tornadoes over Knox, Fulton and Schuyler counties. SBCAPES rise to 2-3k J/kg Fri afternoon as temps warm into the lower 90s and dewpoints in the 70s. Heat indices Fri afternoon reach upper 90s to around 100F and likely the hottest day this week. We have 20-30% pops Fri afternoon over central and northern CWA, highest in north then increase pops during Fri night with 40-60% pops by overnight Fri night from I-55 nw. HREF LPMM shows pockets of 2-4 inches of rain by late Fri afternoon over IL river valley. The upper level trof digs into IL Saturday and an associated cold front moves se into the IL river valley during mid/late Sat afternoon and through rest of central IL during Sat evening and into se IL overnight Sat night. This to likely bring showers and chance of thunderstorms to area on Sat especially Sat afternoon/evening. SPC Day3 outlook has marginal risk of severe storms ne of CWA but will need to monitor risk of strong storms in our area to Sat afternoon/evening along with locally heavy rains. Highs Sat range from mid to upper 80s over central/nw CWA and lower 90s se of I-70 where heat indices peak in the upper 90s to near 100F Sat aftn in southeast IL. Heat indices in 90s over rest of central IL Sat aftn. Frontal boundary still close enough to central IL as it moves se toward Ohio river valley to keep chances of convection around over central and especially southeast IL. Highs Sunday 83-88F warmest in southeast IL where heat indices in lower 90s Sunday afternoon. Heat and humidity build back into area Mon/Tue as upper level ridge builds over IL with 500 mb heights rising above 591 dm on Monday. Highs Mon/Tue in the upper 80s to around 90F and afternoon heat indices in the 90s. Still 20-30% chance of convection Mon and Tue in tropical air mass especially during afternoon/evening hours. 07 && .AVIATION... (For the 12z TAFs through 12z Friday Morning) Issued at 611 AM CDT Thu Jul 10 2025 Area of LIFR ceilings/visibilities is near KBMI and just north of KCMI at sunrise, with the southern edge showing a bit of erosion. Main aviation concern is at KBMI which has 1/8SM visibility this hour, but this should lift before 14Z. However, MVFR conditions at KCMI will occur for the next hour or so. Later in the forecast period, watching some potential for convection late this afternoon triggered by remnants of storms currently in Iowa. However, more of the focus looks to be across northern Illinois, so the PROB30 mentions of TSRA from KSPI-KCMI have been removed. Geelhart && .ILX WATCHES/WARNINGS/ADVISORIES... None. && $$