Area Forecast Discussion
Issued by NWS Central Illinois

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355 FXUS63 KILX 292054 AFDILX Area Forecast Discussion National Weather Service Lincoln IL 354 PM CDT Wed May 29 2024 .KEY MESSAGES...
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- Rain chances (greater than 50% probability) return by Saturday, with additional chances extending into next week. - Heat and humidity will build by the middle of next week with WBGT values creeping toward a Moderate Threat (level 3 of 5).
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&& .DISCUSSION...
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Issued at 1240 PM CDT Wed May 29 2024 The stretch of dry and pleasant weather will run through Friday, at least, as central Illinois remains under the influence of a high- amplitude ridge and its attendant surface high pressure. A pattern change will occur Friday as a northern stream trough emerges and effectively pushes the ridge of high pressure eastward into the Mid-Atlantic region. At the same time, a shortwave trough will begin lifting northeastward across the Ozarks and into the Mississippi Valley. This feature will help draw moist Gulf air northward into central Illinois and augment the forcing/ascent needed for rain. Stubborn mid-level dry air could delay the onset of rain for central Illinois on Saturday, but the evolution of certain features such as the LLJ could support rain earlier in the day. Any nocturnal convection that occurs upstream Friday evening will likely outrun instability as it pushes eastward overnight, and instability progs look fairly poor over central Illinois by Saturday afternoon. But, the devil will be in the details for thunderstorm potential, as a more favorable LLJ position than currently depicted and/or a decaying MCV could afford better convective coverage. A subsident pattern behind the departing shortwave should keep Sunday dry, but then additional shortwave activity is expected to push across the Plains and into central Illinois by Monday with additional rain chances throughout early next week. Perhaps the greater threat as we head into next week will be the heat as mid-to-upper 80s temps return to the region Tuesday and Wednesday ahead of the next frontal system. Wet Bulb Globe Temperatures (WBGT) during this time will have reading in the lower 80s, which corresponds to a moderate heat threat (level 3 of 5). MJA
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&& .AVIATION... (For the 18z TAFs through 18z Thursday Afternoon) Issued at 1218 PM CDT Wed May 29 2024 A high-pressure ridge will keep skies mostly clear through this TAF period, spare a BKN deck of high-based diurnal cumulus. Winds will become light and variable overnight into Thursday. MJA && .ILX WATCHES/WARNINGS/ADVISORIES... None. && $$