2-15-18 IN/IL Forecast: Heavy rain possible south today…cooler air returns Friday – watching for a heavy rain threat next week. N.

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Good Thursday morning! Very mild start across the region, and the warmer air has allowed for thick fog to form across northern Illinois and Indiana mostly where we are melting the snowpack on the ground.  It appears this fog will be sticking around much of the day in these areas.

Showers will increase across the area today, with some pockets of heavy rain/thunder over central and southern locations by this evening into the overnight.  Rain will linger in southern locations for Friday morning, but otherwise we should a clearing trend Friday.  A few snow showers will be possible mainly in the northern half of Indiana Friday morning.  Check out the forecast radar from 9am today to 2pm Friday:

Areas south of I-70 will see the heavier rains where over 1″ is possible.  Generally lighter amounts for northern areas, especially in Illinois.  Southern Indiana is under a marginal to slight risk for rainfall to exceed the flash flood guidance:

As noted on the simulated radar above, isolated light snow showers will be possible in central/northern areas as the colder air works in, but not expecting impacts.  After dry weather Friday night/Saturday morning, a weak disturbance will move in Saturday afternoon/evening with some rain showers south of I-70, and snow showers to the north.  Temperatures for most areas will warm well above freezing 36-40º, so this will limit any impact concerns for most.  Northern Illinois will have the best chance as temperatures there cool near freezing to see a light coating.  This will be a quick hitting system and precipitation amounts should be light.  

Warmer air spreads back in by Sunday with a mostly dry day, then watching a heavy rain threat early next week as a boundary sets-up across the Ohio Valley.  Rain expected Monday and Tuesday, lingering into Wednesday morning.  7-day rainfall could be greater than 3″ in some areas, so flooding is absolutely a threat.