Friday is now a First Alert Day across southern Wisconsin as scattered thunderstorms are expected to develop and some of them could turn strong to severe. The main threats are large hail and damaging wind gusts, with the tornado threat staying low.
That is the weather change people are searching for now because Friday is the day the forecast turns from warm and breezy to potentially disruptive. Temperatures will climb into the low 80s Friday afternoon after morning storms move out, but the timing and coverage of the afternoon storms remain uncertain even with the alert in place.
Thursday sets the stage. It will be warm and breezy across southern Wisconsin, with highs reaching the mid to upper 80s and southwesterly wind gusts continuing through the afternoon. Humidity will drop into the 25 to 35 percent range, but cloud cover will increase as storms build to the north and west.
Those storms arrive first late Thursday evening in southwestern Wisconsin, then slide southeast overnight with lightning and gusty winds. Some areas, especially in the southwest, could see heavy rainfall as storms redevelop, and places that get multiple rounds may end up with one to two inches of rain. That raises the risk of ponding in low-lying areas before any lingering storms weaken after sunset and move east into Friday morning.
The uncertainty is not whether Friday has weather concerns; it is where the strongest storms will line up and how much of southern Wisconsin will get hit. Scattered thunderstorms are expected to form Friday afternoon, then additional storms will move in from the north Friday evening and continue through Friday night before a cold front pushes through early Saturday morning.
For now, the message for southern Wisconsin is straightforward: Friday is the day to watch closely. The severe threat centers on hail and wind, not tornadoes, and the most active period could come in waves rather than one clean line, which makes the exact timing harder to pin down.
