


Area Forecast Discussion
Issued by NWS Central Illinois
Issued by NWS Central Illinois
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263 FXUS63 KILX 071053 AFDILX Area Forecast Discussion...Updated Aviation National Weather Service Lincoln IL 553 AM CDT Mon Jul 7 2025 .KEY MESSAGES... - Seasonably very warm and humid conditions are expected during this work week across central and southeast IL, with highs in the mid to upper 80s today and upper 80s to around 90 Tuesday through Friday. Afternoon heat indices peaking in the lower 90s through Thursday, and mid upper 90s on Friday afternoon. - A chance of showers and thunderstorms over southeast IL today, mainly this afternoon when locally heavy rain and gusty winds are possible with a few thunderstorms. Dry weather prevails across the area tonight with a bit cooler and less humid air arriving. Then a chance of showers and thunderstorms returns to the Illinois Tuesday afternoon and continue through the rest of the week, though most of the time it will be dry this week. && .DISCUSSION... Issued at 345 AM CDT Mon Jul 7 2025 The 09Z/3 am surface map shows a cool front over central IN/IL, (just south of I-72 over IL) and over northern MO. South to SW winds south of the boundary, shift north/ne from I-72 north near 10 mph or less. Dewpoints slowly slipping into the mid to upper 60s from Rushville to Bloomington north while muggy lower 70s from Lincoln south. Mostly cloudy to overcast skies over central and eastern IL with mostly clear skies from Galesburg to Rushville west. Low stratus clouds less than 1k ft over east central IL from I-55 east. Patchy fog also over parts of east central IL, with CMI vsby at 1.25 miles and around Galesburg in Knox county with 1.5 mile vsby. Patchy fog to lift by mid morning though low clouds in eastern IL may linger longer in the morning before breaking up and lifting into cumulus cloud bases. Latest CAMs slowly bring the cold front southward through southeast IL through early this afternoon. Radar mosaic currently not showing much activity with spotty very light rain showers in southeast IL from Danville to Effingham southeast. But diurnally heating of unstable tropical airmass with CAPES rising to near 1500 j/kg in southeast IL this afternoon and PW values 1.8-2.1 inches into mid afternoon in southeast IL to develop bands of convection mainly southeast of I-70 late morning into mid afternoon. SPC day1 does not have a marginal risk today in southeast IL, though a few strong cells possible south of I-70 during early/mid afternoon along with locally heavy rains and lightning. Air mass not as unstable as yesterday afternoon and low level lapse rates not as steep, and also wind shear quite weak again. So this may limit chances of severe storms this afternoon in SE IL. Highs today mostly in the mid 80s with afternoon heat indices in the upper 80s to near 90F in central IL, with lower 90s from I-70 south. Weakening front moves just south of CWA late today/early evening with dry wx expected over CWA tonight as weak 1018-1020 mb Canadian high pressure settles into the Great Lakes region. This will bring a bit cooler and less humid air into central IL tonight, with lows overnight in the low to mid 60s central IL (coolest from I-74 ne) and upper 60s in southeast IL and west central IL toward MS river valley from Macomb to Jacksonville west. A weak northern stream short wave trof moves from the northern plains tonight into IL by Tue afternoon into the Midwest on Tue afternoon and returns chances of showers and thunderstorms from west to east during Tue afternoon. PW values rise back up to 1.5-2 inches during the day Tue and instability increases as CAPES rise to 1500-3k j/kg over western/sw CWA Tue afternoon. SPC Day2 outlook has marginal risk of severe storms for damaging winds over western/sw CWA. WPC Day2 ERO also has marginal risk of excessive rainfall over IL due to tropical PW values returning. Highs Tue in the mid to upper 80s with heat indices peaking in the lower 90s Tue afternoon. Associated weak surface low and front from upper level short wave trof to be near central IL at dawn Wed and to move into southeast IL by Wed evening keeping chances of convection going especially afternoon/early evening hours, with highest pops eastern/se IL. More scattered convection to develop over central and southeast IL Thu afternoon in tropical airmass in place. Another northern stream short wave trof moves into the Midwest late this week enhancing convection chances Fri afternoon into Saturday. Very warm and humid condtions to linger over area into the weekend with highs in the upper 80s to around 90F friday and afternoon heat indices in the mid to upper 90s and likely the highest this week. Seasonable highs in the mid to upper 80s this weekend and still muggy. 07 && .AVIATION... (For the 12z TAFs through 12z Tuesday Morning) Issued at 553 AM CDT Mon Jul 7 2025 Main aviation concern is within the first few hours of the forecast. Ceilings below 500 feet continue over east central Illinois, and development of ceilings near 1000 feet has recently occurred from KSPI-KBMI, with another area about to move southwest into KPIA. This will begin to erode from west to east in a couple hours, though it may take until late morning for KCMI to clear out. Once it does, VFR conditions will prevail through tonight. Geelhart && .ILX WATCHES/WARNINGS/ADVISORIES... None. && $$