29. In chronological order, starting two days ago on May 16th.
A cold front moved southeast across the region Friday (16th), bringing a line of showers and thunderstorms to the northern part of Wisconsin by late afternoon.
This radar screenshot (to the right) is from my GRLevel3 radar program and shows a briefly severe storm at 18:47 over southern Douglas and Bayfield counties.
A Spotter in Bennett (central Douglas Co.) reported shingles blown off his house at 18:17, as well as a wind gust of 59 mph on his personal weather station. This damage prompted a Severe Thunderstorm Warning downstream of this storm.
Thirty-eight minutes later, at 18:55 (and 37 miles southeast), a Fire Department Spotter near Spider Lake (extreme northern Sawyer Co.) reported "many one foot diameter trees down". Amazingly, these two damage reports were the only severe reports in the entire US on the 16th. Both of these reports can be found on the SPC's storm report page.
Trees continuing to leaf-out.
I took this photo (to the left) before noon yesterday (17th) in the front yard, of new Red Maple leaves stretching open for the sunshine.
Most leaves on the trees are about the same size as this Maple, but to give the picture perspective, the leaves are less than an inch long.
More sunshine and rain showers are needed to keep the green-up from stalling, but all the trees are being to have a green tint from afar.
More storms yesterday afternoon.
The atmosphere was cold above the warmer ground yesterday (17th), allowing convection to bubble with diurnal heating of the afternoon.
While most thunderstorms yesterday brought pea-sized hail, low freezing level heights and strong mid-level jet stream winds set the stage for several storms to reach severe limits.
This radar screenshot (above) is from 16:23 and shows a small line of storms across northern Bayfield county that became severe as they moved onshore from the northwest, and continued their strength until central Iron county. A red Severe Thunderstorm polygram outlines the warning area as the storms passed through my area.
Hail began falling at my location around 16:22 and began accumulating on the deck and grass. This first picture (to the left) is looking out the dining room windows at the lawn turning white in the backyard.
The Severe Thunderstorm warning highlighted possible damaging winds (greater than 60 mph), I felt no such winds at my location - hail, rain, and lightning were the only problems here.
I did see four cloud-to-ground lightning strikes that were extremely close to my house. One was half-a-second away, while the others had one second before the house-shaking crash of thunder.
The GFCI outlets in the kitchen tripped during one of the lightning strikes, which confused me at the time. The fuse box showed no tripped fuses but I had an entire wall of dead outlets. Incidentally, my laptop was plugged into these outlets and I had briefly freaked-out that my laptop might be fried. After finding nothing wrong at the fuse box, I sought out the reset button on main GFCI outlet, which brought power back to the circuit.
There are other GFCI outlets in the house, but this is the only one that tripped, something that has never happened to me before. Was one of the strikes so close that it actually caused a voltage imbalance in a circuit? Yikes!
This second picture (to the right) is looking out over the deck at the front yard... hail partly covering the lawn. This was the maximum extent of the hail depth. The hail initially melted on contact, which reduced the depth accumulating on the ground.
Storm reports from these storms.
The storms started up along the Canadian border earlier in the afternoon - the first damage report is from 13:44 with shingles blown off a house in northern Koochiching County, MN. The storms then continued to slide southeast towards Wisconsin throughout the afternoon.
This map (to the left), from the SPC, shows all the storm reports across the US yesterday.
The storm reports from Wisconsin:
16:41: Ashland, Ashland Co. 3" diameter branches blown off trees.
17:00: 2NE Menomonie, Dunn Co. 1" Hail.
17:45: 5S Eau Claire, Eau Claire Co. 1" Hail.
Weather station data from the last 24 hours.
This chart (to the right) is a screenshot from my personal weather station.
Several changes are evident as the thunderstorms pass over my location, just after 4 pm yesterday: temperature drops rapidly, dew point rises, barometer suddenly rises, and a spike of heavy rainfall.
The biggest difference I noticed was the temperature drop... 64 degrees before the rain and hail began, 44 degrees after the rain stopped.
Pea-sized hail.
This last picture (to the left) is of the hail that remained on the deck after the rain stopped. It looks slushy from melting, but added up, I had quit a bit of 1/4" hail fall from this storm. A cool night followed on the heels of the rain, I had 38 degrees as an overnight low. Frost Advisories were posted north of Duluth last night, with new Frost Advisories north of Green Bay tonight. NWS Duluth may issued Advisories for me by this afternoon.
Trees continuing to leaf-out. 
More storms yesterday afternoon. 
Hail began falling at my location around 16:22 and began accumulating on the deck and grass. This first picture (to the left) is looking out the dining room windows at the lawn turning white in the backyard.
There are other GFCI outlets in the house, but this is the only one that tripped, something that has never happened to me before. Was one of the strikes so close that it actually caused a voltage imbalance in a circuit? Yikes!
Storm reports from these storms. 
Weather station data from the last 24 hours. 
Pea-sized hail.