Severe weather chances are heading up for today. There’s still a lot of uncertainty in the forecast with really 3 possibilities for what type of weather we get. Two of those possibilities involve severe weather with a third involving mostly just rain. Here are how the possible scenarios play out.
Scenario #1 (30% Chance)
Line of storms in Illinois this morning is strong enough to cause ripples out well ahead of cold front. These ripples or gravity waves will cause late morning and afternoon rain and
storms that would be close to severe criteria. Rain showers would continue through the overnight hours with overall totals between 1 – 2 inches. Little damage with this scenario but there would be a flooding concern.
Scenario #2 (45% Chance)
We continue to track storms all day off to our west. Windy conditions push temperatures into the 80s and possibly near the record high of 87 degrees. Skies remain mostly cloudy. The line of storms off to our west tightens as we head into the evening hours and begins to roll through. Severe thunderstorm watches are issued around 4pm. On radar you will see a narrow band of reds from north to south that will indicate powerful straight line winds. There would also be a small risk for short lived small tornadoes. We’d likely see some downed trees and power outages with the scenario.
Scenario #3 (25% Chance)
We remain dry this morning with strong winds out of the south pushing temps into the 80s. The sun breaks and we see sunshine shortly after Noon. The sun drives instability to the breaking point and storms begin to fire out ahead of the derecho. These storms begin to rotate as they move off to the northeast. Each
of these storms could potentially drop some hail along with tornadoes. This set-up would be the scariest with the greatest potential for large damage. Notice there isn’t a great chance that we see this scenario play out today.
Part of the reason for today’s moderate risk is the amount of uncertainty there is. Normally the SPC does not issue a moderate risk for ‘just’ a strong squall line. That is where we stand today though. It will be interesting to see which scenario takes place. My money by the way is on Scenario number 2. At this point it is the most likely scenario to play out.