The weather pattern has a similar look to what we faced last week. The big exception is the heat. Last week at this time we were in the midst of another big heat wave. Monday afternoon’s readings are going to turn out just a bit above normal in the upper 80s. The upper air pattern looks similar. We have another fairly decent upper level system moving through the lower Great Lakes. This supports a cool front that will move into the region Tuesday. The upper level system will be slow to move east. So, the unsettled weather unfolding during the next 24 hours will linger into Wednesday.
A southwest flow of warm moist unstable air will move into the region by Tuesday. We will probably get through most of Tuesday morning without having to deal with any precipitation. But by around midday Tuesday we will warm into the lower to mid 80s and that will be enough to destabilize the atmosphere. So, we could be looking at quick developing showers and thunderstorms in the area by midday or early afternoon. Then more activity will follow later in the day into Tuesday night. The atmosphere aloft will be cold enough and the vertical wind flow will be oriented so that we are concerned for a few stronger thunderstorms that could bring very localized severe weather Tuesday afternoon and evening. Our main concern is for damaging winds. The front will be near the region on Wednesday. But the upper level trough axis will be west of the region on Wednesday and the atmosphere will be unstable enough for a stray shower or thunderstorm. But the chance on Wednesday will be much less and only a fraction of the viewing area will probably see anything. A weak area of high pressure will move into the region during Wednesday night and Thursday. This should bring dry and more stable air across the viewing area. We are thinking that the next system looks slower and our chance for precipitation is a bit premature. So, we have backed off on the chance for precipitation on Thursday. Another upper level system and front will bring another chance for showers and thunderstorms to the eastern U.S. on Friday. That system is currently dropping down into northwest British Columbia.