Heavy rain and thunder likely Friday

 

It was another beautiful July afternoon Thursday as temperatures warmed into the upper 70s and low 80s, officially reaching 82 degrees in Rockford. Skies have been clear for most of the day, but we will see cloud cover increase through the evening and overnight as showers and thunderstorms move from the northern Rockies and Plains, into the the Midwest.

Temperatures Thursday night won't be quite as cool as what we woke up to in the morning as the increasing cloud cover and southeast wind help hold in the warmth. Overnight lows will only drop to the low 60s; which is pretty typical for this time of year. An increasing low level jet (stronger winds in the lower levels of the atmosphere) will help pull in quite a bit moisture into the Midwest through Friday morning. This, combined with an upper level disturbance, will bring increasing showers and thunderstorms to the Midwest before sunrise Friday.

Rain could start as early as 2am/3am Friday, but become more widespread through sunrise. Severe weather is not expected, however, heavier pockets of rain could occur throughout the morning. As this initial wave passes, a warm front will slowly lift towards southern Wisconsin through early afternoon bringing dew point temperatures well into the 60s. This will increase the humidity throughout the afternoon and evening as highs near low 80s Friday afternoon.

A stationary front, turned cold front, will begin to move across southern Wisconsin and into northern Illinois late Friday afternoon. As it does, additional showers and thunderstorms are possible. These, too, could contain heavier rainfall as moisture remains high in the atmosphere. There may also be a risk for a few gustier thunderstorms as strong winds could occur as the second wave moves through. There remains a low risk for a few severe storms across southern Wisconsin and northern Illinois, especially if we see a few hours of dry time during the early afternoon. 

When all said and done rainfall totals, for some, could add up to over an inch between Friday morning and evening. As the cold front passes to the south Friday night winds will turn to the northeast for Saturday. This may actually help keep us mostly dry Saturday afternoon before another chance for a few showers return Saturday night and Sunday. Humidity levels are also expected to remain high through the weekend.