571 FXUS63 KILX 051914 AFDILXArea Forecast Discussion National Weather Service Lincoln IL 214 PM CDT Fri Sep 5 2025
.KEY MESSAGES...
- Below normal temperatures in the 70s will prevail for the next few days...before summer-like readings well into the 80s return by the middle and end of next week.
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.SHORT TERM...(Tonight through Saturday) Issued at 214 PM CDT Fri Sep 5 2025
18z/1pm surface analysis shows a cold front south of the Ohio River...while a sprawling ridge of high pressure builds southward out of the Prairie Provinces of Canada into the Central Plains. Despite FROPA, frontogenetic forcing within the 700-500mb layer has yielded a mid-level overcast across much of central Illinois along/south of a Rushville to Bloomington line early this afternoon. While radar imagery is showing very weak returns along and south of the I-72 corridor, the dry boundary layer airmass is preventing any light precipitation from reaching the ground. Would not be surprised to perhaps see a couple sprinkles across the southern two-thirds of the KILX CWA for the balance of the afternoon, but measurable rainfall is unlikely. As a short-wave trough evident on latest water vapor imagery over southern Minnesota into South Dakota pivots southeastward, frontogenetic forcing will increase along/north of the slow-moving surface front tonight. As a result, light showers will develop from the Ozarks northeastward into the Ohio River Valley...with a few showers possible as far north as I-70. Once the front settles further southward, any showers will come to an end by dawn Saturday...followed by partly to mostly sunny skies and pleasant conditions with highs in the lower to middle 70s.
Barnes
.LONG TERM...(Sunday through Next Friday) Issued at 214 PM CDT Fri Sep 5 2025
The cool and dry weather will continue for both Sunday and Monday as afternoon highs remain in the 70s and overnight lows dip into the lower to middle 40s. After that, the unseasonably deep upper low centered south of Hudson Bay will weaken and lift northeastward, allowing upper heights to rise significantly. Models have been consistently showing a vigorous short-wave digging a trough over the Pacific Northwest/Northern Rockies...with downstream ridging over the Midwest by the middle and end of next week. While the exact details of this major pattern shift will likely change a bit over the next few model cycles, confidence is growing that a return to summer-like warmth is in store late in the period. The current forecast features highs climbing into the middle to upper 80s Wednesday through Friday, but there is a potential for even warmer temps depending upon the strength of the upper ridge. 12z Sep 5 NBM shows a low probability (20-30% chance) of temps exceeding 90 degrees both Thursday and Friday...with even higher probs of 30-50% by next weekend.
Barnes
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.AVIATION... (For the 18z TAFs through 18z Saturday Afternoon) Issued at 1231 PM CDT Fri Sep 5 2025
VFR conditions will prevail through the entire 18z TAF period. A mid-level cloud deck at 10,000-15,000ft will spread across the central Illinois TAF sites over the next couple of hours, then will gradually shift southeastward by this evening. While radar is showing a few very weak returns, the boundary layer remains dry and unsupportive of much precipitation reaching the ground. Will however mention VCSH at the I-72 terminals through the afternoon. NW winds will continue to gust 20-25kt through about 22z, followed by a rapid decrease into the evening. Winds will become light/variable overnight before resuming a W/NW direction at 8-12kt by mid-morning Saturday.
Barnes
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.ILX WATCHES/WARNINGS/ADVISORIES... None. &&
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NWS ILX Office Area Forecast Discussion