FIRST ALERT: Multiple storm chances in the cards on Independence Day, some potentially severe

ROCKFORD, Ill. (WIFR) - Independence Day Weekend has started off in grand fashion in the Stateline, but the picture’s looking increasingly murky as the holiday approaches Monday.

The persistently quiet pattern that has been so common for the better part of the past two months is to become decidedly more active beginning Monday, and quite likely remaining so beyond. We’re tracking multiple rounds of stormy weather in the Stateline over the next several days, two of which potentially coming on Independence Day itself, with more storminess quite likely to follow.

Sorting out the specifics of our Fourth of July, while many details are known, others are not. It should be predicated before going any further that this forecast is not etched in stone, and that changes may still very well occur. The following reflects our latest thinking as of late Sunday evening.

Monday’s to start out quietly, with some sunshine possible in the day’s early going. By mid to late morning, clouds are to gather, and the first round of showers and thunderstorms is to develop to our west by the late morning hours.

Current projections place the first round of showers and storms into our region around midday, with storms likely to continue, at least in scattered fashion, through mid to late afternoon. It’s to be noted that some of us may miss out on this initial activity, though that’s far from a given. This first round of storms is highly unlikely to pose much of a severe weather threat, though a few isolated wind gusts and heavy downpours are possible.

A break in the action is likely to follow, so outdoor barbeque plans for the dinner hour may still be safe. That’s before a second, likely more potent line of storms takes aim on the region. This is where things get tricky, as there is the potential that these could have an impact on area fireworks displays during the evening hours.

This second line of storms will likely develop just to our north in Wisconsin. Where, exactly, remains uncertain. There are model projections that suggest storms will blow up over Green and Rock Counties right around 9:00pm, which would obviously be a worst case scenario for many of the area’s fireworks celebrations. Other models, however, develop this second complex a bit farther north, and don’t drop storms into our area until 11pm or later, a far more favorable situation for us, locally.

At this point, it’s impossible to say exactly where and when the storms will develop, and when they’ll affect us directly in the Stateline. What we DO know is that this second round of storms will carry with them a higher severe weather risk, with gusty winds the main threat. Given the extremely warm and humid airmass in place, these storms are nearly certain to be prolific lightning producers, and will also have the potential for depositing some very heavy rainfall, given the fact they’re likely to be slow movers, and could quite possibly back-build to the west as the night progresses. While the very dry ground should largely preclude a flash flooding threat to some extent, rain could fall heavily enough for long enough that localized flooding is not to be ruled out.

We’ll be able to collect our breath early Tuesday, at least to some extent, as sunshine’s likely to dominate for the first half of the day, perhaps longer. However, sunshine and a strong southwesterly wind will allow temperatures to surge into the middle and upper 90s, with heat index values likely to reach the triple digits.

That extremely hot, humid airmass in place will likely prime the atmosphere for more thunderstorms to develop by late afternoon or early evening. These storms, similarly, will have the potential to strengthen rapidly and potentially become severe. Contrary to Monday night’s storms, though, these are to move much more quickly through the region, thus limiting the flooding threat some. Once again, gusty winds would present our main severe weather threat.

Thereafter, a front will settle south of the region, giving us some modest relief from the heat and humidity, though we won’t lose either entirely. Temperatures from Wednesday through Friday will still remain in the middle and upper 80s, and the air will still have a bit of a muggy feel. That, along with our area’s relatively close proximity to that stalled frontal boundary, will keep chances for occasional showers and storms in our forecast daily. While we’re not anticipating much in the way of severe weather during that period, the frequency of the rain could continue to pose at least some risk for flooding.

Computer forecast models continue to consistently advertise rainfall totals in excess of two inches over most, if not all of the Stateline over the next week’s time. While that may mean the week ahead won’t be the most pleasant, such rainfall would be welcome considering the worsening drought situation in and around the Stateline.

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