UPDATE: Peak wind gusts from Monday afternoon
Temperatures Monday afternoon warmed into the upper 70s and low 80s, but the warmth came with a price – very strong southerly winds. Peak wind gusts reached between 45-50 mph in a few locations, and are still around 40 mph as of 6pm.
Those strong winds will ease a bit overnight, but will still remain around 20-25 mph. The southwest wind will pick up once again Tuesday, gusting between 25-30 mph during the afternoon.
Rapidly falling pressure over the Great Lakes is part of the reason why our winds were so strong today. Combine that with mixing down stronger winds above the surface, and it was a recipe for a rather blustery afternoon. Wind is the result of the difference in pressure in our atmosphere, high and low pressure. The stronger (greater) the difference, the higher the wind will be. Low pressure centered over the central Plains Monday has been strengthening, which is what helped draw the warm front north into Wisconsin. The strengthening low is also why the pressure has been falling over the Great Lakes. This also gives us an idea of where low pressure will travel to, as low pressure systems move towards the area with the ‘lowest’ pressure. The good news for us tonight is that the pressure gradient will weaken, allowing our winds to weaken as well. Pressure falls won’t be quite as strong Tuesday, but it will still be breezy as low pressure moves towards northwest Illinois Tuesday night.