Area Forecast Discussion
Issued by NWS Central Illinois
Issued by NWS Central Illinois
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891 FXUS63 KILX 030400 AFDILX Area Forecast Discussion...Updated Aviation National Weather Service Lincoln IL 1100 PM CDT Sun Jun 2 2024 .KEY MESSAGES... - Showers and storms return for the start of the new week with the potential for severe storms on both Monday and Tuesday. - A cooler and drier period looks favorable late in the week through the weekend. && .UPDATE... Issued at 822 PM CDT Sun Jun 2 2024 A quiet night is in store for the local area as high pressure pushes off to our east. This will result in light southeast winds and seasonable temperatures dropping to the lower 60s. Patchy fog is possible closer to the ridge axis east of I-57. A few high-res members show patchy dense fog forming near the Indiana border from 3-7 am. Will watch trends but do not anticipate the need for a dense fog advisory due to the limited time/area and overall low confidence in dense fog. Otherwise high clouds to increase from the west late from convection currently firing over the Plains. Any remnants of this convection should dissipate before reaching the area, but we do carry some low chance PoPs over the northwest CWA after 6 am in case any of these manage to hold together this far east. 25 && .DISCUSSION... Issued at 249 PM CDT Sun Jun 2 2024 Shortwave upper ridging is positioned over the area today with a broad associated surface high situated over the Midwest states. Pesky low stratus lingers over a good chunk of the area this afternoon, with gentle east-northeast winds slowly eroding it. Areas near and west of the Illinois River are mostly clear aside from some diurnal cumulus. High temperatures for today have been lowered by several degrees where 2 pm readings are still in the upper 60s underneath the cloud deck. High temperatures this afternoon should peak in the middle 70s to low 80s with the highest where clouds were quicker to erode. Zonal flow sets up overhead for the start of the new week, with what looks like a more active period with several chances for showers and storms. The remnants of a decaying MCS will approach from the west Monday morning, falling apart just before or as it reaches the forecast area as it encounters a more stable airmass. An outflow boundary left behind from this feature will act as a forcing mechanism for any thunderstorm development later in the day, though this looks to lay out over northern Illinois. Another MCS southwest of here will track across the south-central Plains states tonight, leaving a remnant MCV somewhere over the lower Missouri Valley by Monday morning. This feature will lift northward with a shortwave trough, approaching the Middle Mississippi Valley Monday afternoon. Southerly flow ahead of these mesoscale features will bring in a much warmer and moist airmass with dewpoints climbing well into the 60s. Moderately strong instability will quickly build by Monday afternoon with values looking to top out between 1500- 2000+ J/kg. However, wind shear will be rather weak due to the lack of mid to upper jet support. Despite this, CAMs show thunderstorms developing by mid to late afternoon over Missouri/west-central Illinois with the MCV and another area over northwest parts of Illinois along the outflow boundary. The MCV may act to locally enhance wind shear, but the overall lack of wind shear should prevent storms from maintaining organization. Any storms that do develop will pose a threat for isolated large hail and damaging wind gusts. A stronger upper wave will track from the Pacific Northwest into the northern Plains on Tuesday, sending a cold front toward the Midwest states later Tuesday night into Wednesday. Continued southerly flow ahead of the system will lead to another day of moderately strong instability with dewpoints climbing into the 70s. Upper jet support will once again be displaced to our west/northwest, resulting in relatively weak wind shear. Previous day`s convection may also play a role in any outcomes for Tuesday, with the 12Z run of the NAMnest suggesting the remnants of Monday`s MCV bringing another round of storms as early as Tuesday morning. Additional thunderstorms appear possible later Tuesday night into Wednesday with FROPA, but instability looks to decrease some by then due to loss of daytime heating. Tuesday is another day that bears watching for severe potential. The upper pattern becomes more northwesterly by the end of the week as the strong upper wave occludes and becomes somewhat stationary over the northern Great Lakes Region. Precipitation chances become a little more unknown in the extended due to differences in progression of the upper wave and any shortwaves rippling through the flow aloft, but a drier period does appear to be favored. NMA && .AVIATION... (For the 06z TAFs through 06z Monday Night) Issued at 1100 PM CDT Sun Jun 2 2024 Patchy fog is forecast to develop over eastern IL late tonight, and could extend as far west as KCMI, where a tempo group for MVFR visibility is included. Otherwise, VFR level cu-stratocu will impact the region for much of Mon. Isolated to scattered TSRA will be around the area during the afternoon, and continued PROB30 mention as chances of impacting a terminal are low. South winds will gust to around 20 kt late morning and afternoon. 25 && .ILX WATCHES/WARNINGS/ADVISORIES... None. && $$