Area Forecast Discussion
Issued by NWS Central Illinois
Issued by NWS Central Illinois
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894 FXUS63 KILX 270458 AFDILX Area Forecast Discussion...Updated Aviation National Weather Service Lincoln IL 1158 PM CDT Sun May 26 2024 .KEY MESSAGES... - Another round of stronger storms are possible this evening for areas south of I-72. Discrete cells with the threat of large hail and isolated tornadoes are initially forecast before becoming a line of thunderstorms, with hail and damaging winds as the hazards. - Localized heavy rain and flooding for areas near and south of I-70 as storms, bringing high precipitation amounts, pass through this evening. - The weather calms down after tonight, providing us a benign week of weather. The next chance (30-40%) of showers and thunderstorms arrives Friday night into Saturday. && .UPDATE... Issued at 859 PM CDT Sun May 26 2024 A QLCS/linear thunderstorm system continues eastward along/south of I-70 this evening, generating reports of wind damage and large hail, but so far no confirmed tornadoes this far north. However, a severe thunderstorm watch continues north of I-70 and a tornado watch south of I-70. This feature should exit southeast IL into Indiana by 10 PM. The cold front associated with this system appears to be roughly along the Illinois River as of 830 PM, however subsidence and increasing CIN behind the QLCS should eliminate the severe weather threat. Overnight, the front will continue to traverse the central IL forecast area, exiting the area by around sunrise. Overnight, a few more showers and thunderstorms could be triggered by the front, while winds will switch to northwesterly and trigger some cooler temperatures with lows in the mid 50s to lower 60s south of I-70. Updates have been sent for trends in precipitation coverage this evening, and a couple degrees off of lows for tonight. 37 && .DISCUSSION... Issued at 233 PM CDT Sun May 26 2024 The next round of storms is possible this evening, mainly near and south of I-72. There is some uncertainty whether this round will make far enough north to be in the CWA or not but the newest HRRR and ARW show it just south of I-72. These are likely to be supercell structured with a large hail and tornado risk early in the event (21z-00z). Then will merge into a more linear form as it exits southeastern Illinois, posing more of a hail and damaging wind risk. The HRRR 12z soundings show STP of 1, SHIP of 2.1, midlevel lapse rates of ~8 C/km, and PWATs of 1.5-1.9 inches for this evening. We kept the Flood Watch for south of I-70 because of the higher PWATs, and the potential for training cells. After this evening, the weather will clear out. Memorial Day will be nice and dry with highs in the low to mid 70s. There could be some breezy winds at times, particularly late in the day. From the 12z HREF, there is a 50-60% chance of wind gusts greater than 30 mph in the late afternoon into the evening hours, then calming down by the overnight hours. Temperatures through the extended forecast will gradually warm up by next weekend. Low to mid 70s for highs through Thursday, then reaching the upper 70s to low 80s. The next significant chance for precipitation comes Friday night into Saturday, with 30-40% chance of showers and thunderstorms. Copple && .AVIATION... (For the 06z TAFs through 06z Monday Night) Issued at 1158 PM CDT Sun May 26 2024 A cold front will continue to push through the central IL terminals for the first few hours of the forecast period, with little or no chance for any precipitation developing along the front at this point. However, an area of MVFR cigs is poised just upstream, and is expected to move over most of the area overnight. Lifting and dissipation of this cloud cover should result in VFR conditions by 13Z-16Z. Another shortwave will arrive in the afternoon, resulting in widely scattered showers and thunderstorms mainly near and north of the I-74 corridor until around 04Z. Winds NW around 10 by 06Z-11Z, increasing to 12-16 kts with gusts 20-25 kts by 16Z. Winds decreasing after 01Z. 37 && .ILX WATCHES/WARNINGS/ADVISORIES... None. && $$