Area Forecast Discussion
Issued by NWS Central Illinois
Issued by NWS Central Illinois
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755 FXUS63 KILX 301858 AFDILX Area Forecast Discussion National Weather Service Lincoln IL 158 PM CDT Thu May 30 2024 .KEY MESSAGES... - Showers and thunderstorms return to the forecast Friday night into Saturday (70-80 percent chance). Severe storms are not expected but there is around a 30 percent chance for some areas to see over an inch of rain. - Additional showers and storms are expected Monday through Wednesday of next week. && .DISCUSSION... Issued at 152 PM CDT Thu May 30 2024 This afternoon, high pressure is centered over the western Great Lakes with ridging extending across east central Illinois and to the lower Mississippi Valley. To our west, troughing stretches across much of the Great Plains. In the near term, fair weather will continue across central Illinois under the influence of the ridge. As the ridge shifts to our east Friday, S/SW flow will overspread central Illinois. A favorable fetch off of the Gulf of Mexico will advect higher dewpoints towards central Illinois. While this will be partially offset Friday by deep mixing into dry mid levels, dew points will eventually build back into the 60s over the weekend. Meanwhile, a shortwave trough is progged to push across central Illinois Friday night into Saturday. This will bring the next chance for showers and thunderstorms to the area. Given the unfavorable diurnal timing of the wave, instability will be weak (around 200-300 J/kg MUCAPE) and elevated, rooted generally between 700-900mb. Severe storms are not expected due to these conditions, but locally heavy rain appears possible. PWats are expected to increase to around 1.6 inches and the slow moving upper level disturbance and weak flow aloft in the vicinity of the wave will result in slower storm motions. HREF LPMM (which only covers through 12Z Saturday) shows a narrow swath of 1.5-2.0 inches of rain. NBM 90th percentile shows similar values across the area through Saturday evening. Behind the departing wave, ridging will briefly build back across central Illinois Sunday providing a break in the rain chances most of the day. Warm and humid conditions are expected instead with highs in the lower 80s and dew points in the lower to mid 60s. An initially zonal upper pattern early next week will gradually give wave to digging trough evolving into a closed upper low by midweek. There will be some chances for showers and storms Monday and Tuesday as low amplitude waves move through the zonal flow, but precip chances continue Wednesday as the closed upper low digs into the Upper Midwest. Forecast PoPs are a bit broad brushed Monday through Wednesday owing to timing differences in the models, and anticipate plenty of dry hours on those days despite the persistent chance PoPs. In addition, the midweek system could be accompanied by an increase in shear and instability so wouldn`t rule out some severe weather potential somewhere in the region, though at this distance plenty can change. Deubelbeiss && .AVIATION... (For the 18z TAFs through 18z Friday Afternoon) Issued at 1239 PM CDT Thu May 30 2024 Surface high pressure across the Great Lakes will maintain dry conditions throughout the forecast period, though a few cumulus around FL050 that popped up on satellite over the past couple hours will continue to percolate near and south of I-72 this afternoon. Mid to high clouds will increase tonight into tomorrow, while light and fickle winds increase and become more steadily out of the southeast tomorrow morning, gusting over 20 kt after around 15z (10am CDT). Bumgardner && .ILX WATCHES/WARNINGS/ADVISORIES... None. && $$