From summer to fall in a few short days

The current cloud cover will continue to thicken before possibly thinning a bit by this afternoon.  A series of upper level lows moving through the Midwest will help usher in below average weather by the end of the week. 

The first is what's left of overnight thunderstorm activity in Iowa.  While the rain shield has thinned a bit in northeast Iowa a 'mini' low has developed and will move into northern Illinois shortly afternoon noon today.  This will help keep the cloud cover around but also bring the threat for a few sprinkles or light rain showers by this afternoon.  A second and stronger low in Minnesota will swing through this evening.  Skies have been clearing in central and western Iowa between the two systems and it's there that strong to severe storms could develop ahead of the second low later this afternoon. 

The threat for rain will increase overnight into Thursday morning and it looks like a decent amount of rain could occur.  While model rainfall outputs have varied a bit the past couple days some locations could receive close to three quarters of an inch with higher amounts possible in thunderstorms.  The main upper level low will amplify by Thursday afternoon as it moves across the Great Lakes and if skies clear enough and instability builds the threat for stronger storms may exist just south of Rockford.  Unseasonably cool air will accompany the low and as that cooler airmass moves over the warm waters of Lake Michigan lake effect rain will set up for northeast Illinois by Thursday night.  Another threat for the shores of Lake Michigan will be waterspouts Thursday evening!