Good afternoon everyone! Just wanted to provide a quick update on the evolution of the incoming storm system late tonight through Monday. The remainder of the day today will remain dry with the next rain chance not lifting into southwestern IL until after midnight tonight. There is the risk for showers and storms into the day Sunday, however it definitely won’t be widespread and there will be plenty of dry time into the day. With these showers and storms comes the potential for a few strong to severe storms in the afternoon and evening, particularly in the shaded region in the first image below. Widespread cloud coverage is anticipated even after scattered morning convection moves through the area to the northeast. This should help to limit how unstable the environment can become. Regardless, plenty of moisture (dew points rising into the lower 60s) will lift northward ahead of an approaching boundary from the west during the afternoon, helping to provide at least some instability (fuel for storms) for some of the storms that do develop to become strong to severe. The main threat would be damaging winds but hail and/or a couple isolated tornadoes can’t be ruled out, especially into southern IL/IN. Shown in the second image is the Storm Prediction Center’s Outlook for severe weather Sunday afternoon/evening, particularly highlighting the risk in southern IL/IN and south.
Simulated radar through 8am EDT Monday: Dry weather maintains through the evening for the Ohio Valley, then scattered convection in the form of showers and a few storms will lift into southwestern IL mainly after 12am EDT that pushes northeastward across the remainder of central/southern IL through the overnight. Far southwestern IL towards the Evansville area will work in this activity by the 4am EDT hour. Expect this scattered wave of showers and a few storms to continue to progress northeastward through the morning across northern IL, the remainder of IN and southwestern OH, likely reaching Indy in scattered coverage around 9am EDT. This feature pushes through northeastern IN and OH through the afternoon hours with additional scattered coverage of showers and storms, possibly strong mainly from 10am EDT and onwards along the southern thirds of IL/IN. The model shown below may be a tad underdone and slightly too far south with this activity. Then, the boundary from the west inches closer and enough forcing will allow for a line of widely scattered showers and storms, possibly strong, to develop in central IL late afternoon and evening and pushing eastward through the evening (some northeastward development into northwestern IN). We did want to note that this model is later on its timing than most guidance with these showers and storms developing along this boundary, but the shortwave trough (disturbance) associated with it will still be west. These scattered showers and storms continue eastward through the evening and overnight across southern IL, central IN and far western OH before largely weakening as the overnight progresses. Spotty showers and/or a few storms can develop out ahead of this boundary and by Monday morning, isolated showers and/or a few storms will remain into OH with shower activity hugging the Ohio River.
Total precipitation through Sunday night: Most of the precipitation that affects the region through this time will be scattered in nature (some in northern IL can observe less than 0.1″ of rain total). However, where the better chances for showers and storms occur, including the southern half of IL, IN and OH, a general 0.2-0.6″ of rain is expected. Localized pockets of ~1″+ will be possible and most likely in any heavier storms and just south of the Ohio River.
Simulated radar from 8am-8pm EDT Monday: As previously stated, most of the showers with embedded storms by the start of this loop will be residing along the Ohio River with scattered showers/storms possible into OH. This activity will continue to work eastward through the day as the storm system exits. By 8pm EDT Monday, the Ohio Valley will once again be mainly dry, though an additional weak wave from the north will be lifting into far northern IL with scattered showers at this time.
