


Area Forecast Discussion
Issued by NWS Central Illinois
Issued by NWS Central Illinois
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807 FXUS63 KILX 140505 AFDILX Area Forecast Discussion...Updated Aviation National Weather Service Lincoln IL 1205 AM CDT Tue Oct 14 2025 .KEY MESSAGES... - The next chance for widespread rainfall is slated for next weekend. The latest NBM guidance has become a bit more optimistic...with probabilities for greater than half an inch increasing to 50-60% across most of central Illinois. - There is a 15% chance for severe thunderstorms Saturday afternoon and evening...mainly along and south of a Springfield to Robinson line. && .SHORT TERM...(Tonight through Tuesday) Issued at 229 PM CDT Mon Oct 13 2025 18z/1pm surface analysis shows a weak cold front crossing the Mississippi River. The band of very light showers from earlier today has pushed eastward to the Indiana border and diminished significantly...but a few sprinkles will remain possible along/east of I-57 for the next couple of hours. Further west along the front, no precipitation is observed...although a band of Cu has formed. The front will continue to lose forward momentum as it shifts slowly eastward and essentially stalls across the area tonight. Given minimal forcing along the boundary and very weak upper dynamics, am expecting little more than an increase in cloud cover later this evening through the overnight hours across the W/NW half of the KILX CWA. NAM/RAP forecast soundings indicate a dry boundary layer with a pinch of moisture developing from 5000-8000ft aloft. The clouds will be most prevalent near the front along/north of a Rushville to Bloomington line...while locations further S/SE should remain partly cloudy. While soundings and CAM guidance do not really support it, am concerned that fog may form across areas that saw the light showers today...particularly where it does not become completely overcast. As a result, have added patchy fog along/south of a Rushville to Bloomington line...and north of a Taylorville to Champaign line. After any early morning fog dissipates, am expecting partly to mostly cloudy conditions across the N/NW CWA with mostly sunny skies further SE on Tuesday. Lows tonight will range from the lower 50s near the Indiana border to around 60 in the Illinois River Valley. Highs on Tuesday will range from the middle 70s far northwest around Galesburg to the lower 80s along/south of I-70. Barnes .LONG TERM...(Wednesday through Next Monday) Issued at 229 PM CDT Mon Oct 13 2025 A mostly uneventful work week lies ahead as central Illinois remains under the influence of prevailing upper-level ridging. After a slight cool-down into the lower to middle 70s on Wednesday, readings will climb back into the upper 70s and lower 80s by Friday. After that, the weather becomes more active over the weekend as a cut-off low progged to form over northern California on Monday gradually opens and lifts northeastward by the end of the week. As this process unfolds, deep-layer southwesterly flow will develop across the Plains/Midwest. This will help pull better moisture into the region and result in a more significant chance for rainfall from Friday night through Sunday. The GFS remains about 6 hours faster with its FROPA midday Saturday, while the ECMWF/GEM are both slower. Given the highly amplified pattern in place and the strength of the upper ridge, think the slower solutions are prudent. With that said, showers and perhaps a few thunderstorms will push into the Illinois River Valley late Friday night...with re-development of showers/storms mainly east of I-55 Saturday afternoon/evening. With deeper moisture in place and strong upper dynamics ahead of the approaching upper wave, strong to potentially severe thunderstorms may develop during peak heating if the slower ECMWF/GEM verify. The 00z LREF shows about a 20% chance of SBCAPEs exceeding 500J/kg and 0-500mb bulk shear greater than 30kt by 00z Sun along/south of a Springfield to Robinson line. As a result, the latest SPC Day 6 Outlook highlights this area for a 15% chance for severe on Saturday. The next forecast question will be how much rainfall will occur with the weekend system. Synoptic models often handle antecedent dry soil conditions quite poorly, so raw QPF from any model at this point should be taken with a grain of salt. In addition, if severe weather becomes widespread further south across the Ozarks into western Kentucky where parameters are more favorable, this could potentially intercept some of the Gulf moisture flowing northward. While NBM probabilities for greater than 0.50 have increased to 50-60% across most of central Illinois, think this may be a bit too optimistic given the mitigating factors in play. Feel that the best bet for significant rainfall from this system will be along/south of I-70 where probs for more than 1 inch of rain have nudged up into the 40-50% range. Barnes && .AVIATION... (For the 06z TAFs through 06z Tuesday Night) Issued at 1205 AM CDT Tue Oct 14 2025 An ill defined and slow moving frontal boundary has resulted in numerous clouds around FL050 to FL070 early this morning. Though there are a few breaks which could theoretically allow patchy fog formation from roughly 09-13z/4-8am CDT, HREF and NBM each suggest chances for MVFR (or lower) visibilities is less than 10% and so confidence was too low to justify a mention in the TAFs. Winds will remain light (less than 8-10 kt) and somewhat shifty, especially this morning, but the direction will be some variation of northeasterly through 06z/1am CDT Wednesday. Bumgardner && .ILX WATCHES/WARNINGS/ADVISORIES... None. && $$