After a few heavy rain showers passed through the region last week, the upcoming week looks to be a little more dry. And while the middle to the end of the week will feature almost daily rain/thunder chances, those chances remain somewhat isolated.
A strong ridge of high pressure remains over the Plains and West sending temperatures soaring into the triple digits across the western High Plains and northern Rockies. Across the Midwest and Great Lakes, northwest flow has set up within the jet stream. Within that northwest flow there are several upper level disturbances that will move down from the Plains, into the Great Lakes, before quickly shifting off to the east.
Each disturbance that passes through will pull a cold front down over the Great Lakes and into southern Wisconsin and northern Illinois. The first of those fronts is set to arrive Tuesday evening. With surface winds directed more from the north, moisture will be in limited supply as the front comes through. This means only an isolated shower or storm will be possible locally Tuesday late afternoon and evening. The higher chance for showers/storms will be to the north in Wisconsin. That front will settle to our southwest during the day on Wednesday before pulling back north as a warm front Thursday.
This will turn our surface winds more to the southwest for the afternoon, not only bringing temperatures up into the upper 80s, to near 90 degrees, but also allowing dew point temperatures to rise as well. Dew points Monday afternoon mixed down into the low to mid 50s in some locations, keeping both the heat index and humidity at more comfortable levels.
By Thursday afternoon dew points will warm into the upper 60s, to near 70 degrees, pushing the heat index into the low to mid 90s through the end of the week, and then possibly into the upper 90s to near 100 degrees for the weekend. But that warmth all depends on the exact position of the next front. As the warm front remains north of the area on Thursday, it’ll be pulled back south as a cold front Friday. This may generate just enough lift to provide us with a few showers and thunderstorms during the afternoon and evening. As the winds in the jet stream continue from the northwest into Saturday, the chance for thunderstorms will be present with the frontal boundary close by; some of which could be on the stronger end of things if parameters line up just right.
As it looks now, we remain on the ‘warmer’ side of the boundary which would keep temperatures in the low 90s through the weekend. Another cold front is set to come through Sunday but the cooler air lags a bit with highs still in the 90s for the afternoon.