Last heavy rain threat before warmth builds midweek

Skies were able to dry out after the rainfall we had late Sunday night and early Monday morning.  The few peeks of sunshine this afternoon allowed temperatures to climb back into the low to mid 70's. 

Another round of rain and thunderstorms, likely non-severe, are expected to move back in overnight Monday into Tuesday morning.  Through roughly 9pm, most of Northern Illinois and Southern Wisconsin will remain dry.  The storm threat will ramp up between 10pm and Midnight and continue through 6am Tuesday morning.  Many of our forecast models indicate the rain will be heaviest through roughly 3am/4am.  By mid-morning, most of the rain should be over with, but the front will be very close to the area which will continue the threat for additional showers throughout Tuesday.

Showers and storms that have been developing south, have been forming along a cool front that passed through Sunday night.  An upper level wave of energy to the west in the Plains will move along the boundary and help focus those showers and thunderstorms back northward into the Stateline.  Severe weather isn't expected, but heavier rainfall and small hail will be common - very similar to what occurred late Sunday night.  The storms out in Southern Iowa and Northern Missouri are being enhanced by the low level jet.  Eventually, the low level jet will begin to shift and point more towards eastern Iowa helping to move the storm activity east overnight.

By Wednesday, the jet stream will position itself to the North of the Stateline essentially blocking storm development to the west.  This will allow temperatures to warm Wednesday and Thursday.