The risk for strong to severe storms will return Wednesday afternoon as a cold front and low approach from the northwest, pushing temperatures into the mid and upper 80s and dew point temperatures close to 70 degrees. But there are still some questions regarding just when, and how severe, storms may get for Wednesday afternoon as a couple scenarios are possible.
For the rest of Tuesday evening skies will remain partly cloudy. Afternoon temperatures got a nice little boost thanks to the return of the sun, warming most into the low 80s. A weak low moving through Iowa has been responsible for a few showers and isolated thunderstorms Tuesday afternoon. That low will slide to our southwest later tonight, likely giving us a few more clouds during the overnight. Overnight lows will fall to the mid 60s.
Wednesday will start off dry with plenty of sunshine that’ll take us into the early afternoon. Low pressure currently over Montana will be moving through the Plains and Midwest Wednesday morning, before entering into Minnesota and Wisconsin Wednesday afternoon. The entire Stateline is outlined with the potential risk for strong/severe storms Wednesday afternoon and evening, with a slightly higher potential stretching from south-central Wisconsin into northwest Illinois.
Severe weather for us Wednesday afternoon will be highly dependent on where, and how far south, the low over Montana travels and if we’re able to break the ‘cap’ (lid) on our atmosphere. Southwest winds will usher in a much warmer, and slightly more humid, air mass Wednesday, bringing temperatures into the mid and upper 80s and dew point temperatures into the upper 60s and low 70s. But just how high the dew point temperature gets will be key in determining if the cap on our atmosphere weakens. If dew point temperatures rise into the low 70s it’s possible that we could see storms develop along the southern edge of that storm complex that’ll be moving through Minnesota, northern Iowa and Wisconsin Wednesday afternoon.
This would allow the air in the atmosphere to quickly rise, forming strong/severe storms as early as 1pm/2pm. If, however, dew point temperatures remain in the 60s it’s possible that the cap would then hold, keeping the storm threat further north – or right along the state line. If storms were to develop Wednesday afternoon, all types of severe weather would be possible – including tornadoes. If the afternoon remains mostly dry then our chance for thunderstorms would be late Wednesday evening, overnight and Thursday morning as a cold front nears from the northwest. With that second round, heavy rain could become a concern into Thursday morning. Depending on how much skies clear following the rain in the morning, thunderstorms are possible again during the afternoon and evening.
Wednesday will be a day you want to remain ‘Weather Aware’ and make sure you pay attention to the forecast throughout the day. If the chance for strong/severe storms does occur during the afternoon, make sure you know where to seek shelter should any warnings be issued.