I know, what is a MCS? It stands for Mesoscale Convective System. They have been called other things such as MCC, Mesoscale Convective Complex and MCV...Mesoscale Convective Vortex. Either way, the idea is that this is a complex of thunderstorms that are very common in NW wind flows. They sometimes look like a mini low pressure with a warm front/cold front look to them. They can be dangerous however when it comes to high winds as it bows out. Tornado threat is low, but most common on the bottom/south edge of them. We typically see these in June/July.
Tomorrow is a good setup for one to form to our north. HPC shows the showers/storms forming in N IL.
They like to follow a track..like a locomotive. That would be the warm front that will pass through tomorrow. Where that front sets up is key on how close this complex will reach us.
As the MCS tracks south east, it will hunt for high dewpoint areas...so it is likely it will take a right turn at some point like I have drawn below.
As of right now, this impact looks to stay just east of our viewing area. But I only am posting this as there is a chance the warm front could be closer than forecast---and if so---the MCS may impact our eastern counties Sunday afternoon.
SPC has a small outlook out for this now: only 5% which is below SLIGHT RISK level.
Next SPC update is at 130pm.
UPDATE: SPC just upgraded SE IN/OH and far NE KY into a SLIGHT RISK for severe storms with the latest upset.
I would plan for a nice/warm day for now...with at least some cirrus clouds steaming over in the afternoon from this. We will watch the trends carefully to see how it evolves. Still have 24 hours.