Area Forecast Discussion
Issued by NWS Central Illinois
Issued by NWS Central Illinois
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848 FXUS63 KILX 240907 AFDILX Area Forecast Discussion National Weather Service Lincoln IL 407 AM CDT Tue Sep 24 2024 .KEY MESSAGES... - Widespread showers and a few thunderstorms will continue today across central and southeast IL, gradually diminishing in coverage from west to east during this afternoon and early evening. Rainfall amounts will be variable today, with some areas getting a tenth to quarter inch and others getting as much as a half to 1 inch. - A prolonged period of unsettled weather is expected late this work week into early next week, with rainfall starting Thursday afternoon and Thursday night, and more widespread showers expected Friday into this weekend. && .DISCUSSION... Issued at 400 AM CDT Tue Sep 24 2024 Early morning surface map shows 1008 mb low pressure near St Louis with its warm front near I-70. Areas of fog had developed past few hours north of the warm front over much of central IL with pockets of dense fog along and southeast of a Bloomington to Quincy line to along I-72. We issued a special weather statement for areas between the IL river and I-70 for the dense fog possibility into mid morning. Aside from the fog, radar mosaic shows an area of showers and a few thunderstorms lifting ne western and sw CWA especially in nw Knox county and into areas between Springfield, Taylorville and Litchfield and approaching Decatur. More widespread convection was just se of IL into south central and se Indiana supported by a 25-30 kt sw low level jet. PW values also range from 1.5-1.75 inches, highest in southeast IL where moderate to heavier rain showers occurred during Monday evening. Dewpoints ranged from upper 50s from Peoria north to mid to upper 60s from I-72 south and temps are near dewpoints se of Peoria along with light to calm winds helping produce widespread fog. The latest CAMs lift low pressure ne into north central Indiana by mid afternoon and pushing cold front east of the Wabash river around noon today. Showers will be likely this morning with isolated thunderstorms, and diminishing trends from west to east during the afternoon as low pressure pulls further ne away from central IL. SPC Day1 outlook keeps marginal risk of severe storms east of IL this afternoon with slight risk in central and eastern KY where stronger instability and wind shear will be ahead of the cold front. Highs today in the upper 60s to near 70F from I-72 north and mid 70s southeast of I-70 which is in warm sector this morning. Isolated showers linger in southeast IL early this evening otherwise quiet weather expected tonight. A few CAM members show patchy fog late tonight though better chance of fog development to be over central and northeast Indiana. Cooler lows tonight in the lower 50s nw of I-55 and upper 50s in southeast IL. Weak high pressure tracking from the Central Plains into the upper MS river valley and western Great Lakes on Wed afternoon will provide dry weather to areas nw of the IL river. However an upper level trof near the eastern Dakotas and MN border to deepen and form a strong cutoff upper level low into southeast MO by Wed afternoon. The 00Z model suite now showing low chances of light rain showers by Wed afternoon over portions of central and especially eastern IL. Highs in the low to mid 70s Wed with more sunshine possible nw of the IL river where warmest temps may likely be. National Hurricane Center has Potential Tropical Cyclone Nine south of western Cuba developing into Hurricane Helena by sunset Wed as it track northward over the eastern Gulf of Mexico and reaching the Big Bend of Florida gulf coast by sunset Thu with winds of 100-110 mph. There is a chance of rain showers lifting northward into southeast IL Thu morning and into parts of central IL Thu afternoon, with increasing chances of rain showers from south to north during Thu night and Friday. Remnants of hurricane track northward toward south central KY by sunset Friday. The strong cutoff upper level low meandering over AR Thu and Fri to likely steer the remnants of this system back into the lower/middle Ohio river valley Fri night and possibly back into southern IL Saturday as its absorbed into the cutoff low lifting into the mid MS river valley Saturday and ne over the Ohio river valley Monday. Looks like an extended period of unsettled weather over central and southeast IL late this week through early next week. Rainfall amounts of 1-2 inches could occur if this track occurs with 2-3 inches in southeast IL and over 3 inches in sw IL near the MO border from St Louis south. This would be beneficial rainfall if it occurs due to the drought that has recently developed over southern IL and parts of central and northern IL. 07 && .AVIATION... (For the 06z TAFs through 06z Tuesday Night) Issued at 1158 PM CDT Mon Sep 23 2024 Low pressure centered near St Louis late this evening will lift across central Illinois overnight into Tuesday morning. Rain and IFR/LIFR ceilings will accompany the low passage overnight with the heaviest rain south of PIA to BMI. Light and variable winds are expected with the low, then will set up out of the northwest behind the departing low late morning to around midday as conditions gradually improve back to MVFR and precip chances diminish. VFR conditions will return later in the day. Deubelbeiss && .ILX WATCHES/WARNINGS/ADVISORIES... None. && $$