Cloud cover has been slow to leave the Stateline Monday afternoon holding temperatures for most in the mid to upper 40s. Breezy northwest winds have also kept wind chills about five degrees cooler than the actual air temperature. Winds will begin to lighten up through the evening as high pressure slides closer to the Stateline. Temperatures Monday night will drop to the mid 30s, rising into the mid 50s for Tuesday afternoon.
An active week lies ahead as a rather large storm system stalls out over the Midwest and Great Lakes mid-week, keeping rain – and even snow chances – in the forecast. Southerly winds Tuesday will bring temperatures into the mid 50s during the afternoon and hold temperatures in the 50s through much of the evening. A stalling low pressure system across the Dakotas will pull a cold front through northern Illinois and southern Wisconsin Tuesday evening.
Ahead of the front, moisture will be pulled northward allowing showers to develop Tuesday evening. There could be an isolated shower or two Tuesday afternoon, but the steadier rainfall is expected to come down Tuesday night, most likely after 8pm/9pm. Rainfall totals Tuesday night will again range from a quarter of an inch, to half an inch, by early Wednesday.
Drier air quickly wrapping in behind the front Wednesday will cause conditions to dry out before sunrise, leaving much of Wednesday with a partly cloudy sky. West winds will increase, gusting to around 30 mph, during the afternoon. Surface temperatures will warm back into the mid 50s Wednesday, but temperatures aloft quickly fall below zero as a very cold pocket of air settles into the Midwest and Great Lakes. This colder air will help build a little instability during the afternoon which could lead to isolated showers late Wednesday afternoon and evening. Moisture will be very limited following the cold front Wednesday, but some of the instability may be able to overcome that. If a few steadier showers develop, gusty winds and even small hail are possible.
Low pressure will then slow down quite a bit, spinning across the Great Lakes Thursday and Friday. Colder air wrapping in around the low will bring temperatures down into the 40s both days, keeping the risk for isolated showers – and perhaps a snow shower or two mixing in. Temperatures will be slow to rise on Saturday with highs in the upper 40s and low 50s as high pressure builds in, but then rise to near 60 degrees Sunday and low to mid 60s Monday. Temperatures are actually expected to rise above average next week as the active jet stream carves out a trough of low pressure over the west. This will, however, place us closer to the more active storm track which could also give us some rain and thunder opportunities throughout much of next week.