After a widespread 1 to 2 inches of rain from Wednesday’s round of storms and some isolated higher amounts, and with more heavy rain expected, the National Weather Service has issued a flash flood watch for the southern two-thirds of Wisconsin.
A flash flood watch is in effect for Chippewa, Dunn, Eau Claire, Pepin, Pierce and St. Croix counties until 7 pm Wednesday; Buffalo and Trempealeau counties until 1 am Friday; Clark, Jackson and Taylor counties until 7 am Friday.
The first of multiple rounds of storms for Thursday started around 4:30 am and will likely continue through the early morning hours. This round comes ahead of a warm front that will slowly increase temperatures throughout the day and increase instability for other storms.
Another round is already in progress in southern Minnesota which is displaced east from a surface cold front that extends through Nebraska. This will bring a second round possible through midday.
The potential 3rd round of thunderstorms is expected after 2 pm. As that cold front sweeps across Iowa and Minnesota and sparks a strong line of thunderstorms. The Storm Prediction Center has parts of the Chippewa Valley in a level 1, marginal risk, for severe weather as these storms pass, while the stronger severe threat remains to the south.
The threats possible will be strong straight line winds, heavy rain, large hail, and we can never rule out an isolated tornado. We are expecting another 1 to 2 inches of widespread rainfall through Friday morning with isolated higher amounts. We’ll finally start to see the end of the extended rainfall on Friday.
Friday afternoon may see a few pop up isolated rain showers, but it will be very windy as the flank of this passing low pressure center spins wind speeds upwards of 15 to 25 mph and gust up to 40 mph. It will also be cold and mostly cloudy.
The weekend though looks mostly dry with just a brief overnight shower Saturday into Sunday morning but warmer and humid conditions are expected next week.