29. It's been dry across the Northwoods, but things began changing yesterday: warmer with rain & storms.
I wanted to start this post with this map (to the right), from AHPS, that shows percent departure of 'normal' the last thirty days.
Areas in the yellow/orange/red coloration are below 'normal, while greens/blues are above. I drew some black lines that separate areas above from areas below.
The point I wanted to make is that for the last month, we've experienced below-average precipitation across the entire region. I know I could use some rain, and it looks like other areas would benefit also.
A strong low pressure began impacting the region last night.
It's strong enough, with the right ingredients in place, to warrant severe risk classification from the SPC.
This map (to the left) shows the convective outlook issued by the SPC yesterday. Tornado watches were in effect last night from western Wisconsin down through Texas.
Today, the SPC has most of Wisconsin and the UP of Michigan in a SLIGHT risk of severe weather.
Plenty of moisture for heavy rain.
This low pressure system has excellent Gulf of Mexico moisture to work with, and therefore storms have been able to produce plenty of rain.
This QPF map (to the right), from the HPC, shows yesterday's forecast for liquid precipitation, ending this morning. NWS Duluth & NWS Minneapolis saw enough of a threat to issue a Flash Flood Watch across the northern parts of Minnesota and Wisconsin.
It turns out that some locations saw up to 5" of rain from heavy thunderstorms.
Two counties along the north shore of Lake Superior in Minnesota - Cook & Lake counties - had water across highways this morning, prompting a Flash Flood Warning to be issued in these locations.
This graphic (to the left) shows radar estimated precipitation from the radar site in Duluth, ending this morning.
From the color scale on the left of the image, it's easy to see that many locations possibly received over 1" of rain, with some locations seeing as much as 3".
However, the radar doesn't seem to have caught all the rain in it's estimate, based on reports. Observer reports at 7:00.
I clipped this information (to the right) from NWS Duluth's Public Information posting.The highest rainfall in Minnesota fell in areas that were warned of the Flash Flood this morning:
4.96" at Grand Marais (Cook Co.) 4.76" four miles north of Grand Marais (Cook Co.) 4.76" at Tofte (Cook Co.) 3.63" at Silver Bay (Lake Co.)
In northwest Wisconsin, Douglas and southern Ashland counties had the highest rainfall amounts.
2.20" at the mouth of the Bois Brule River (Douglas Co.) 1.99" at Maple (Douglas Co.) 1.49" at Butternut (Ashland Co.)
I matched the report north of Bayfield with 0.91" at my house, enough rain but not too much. The storms overnight.
I woke up before 4:00 AM to the sound of increasing thunder, and my lightning sensor chirping.
Since I was going to get up and unplug the TV equipment, I thought I might-as-well get a look at radar.
This GR screenshot (to the left) was the radar capture that I got at 3:57, from NWS Duluth's radar site.
There have not been many reports of damage overnight, but I did find this one (to the right) plastered across the Northland's News Center from Duluth, MN.
The only other damage report that I found listed was from north of Duluth this morning:
4:50. Lutsen, Cook County. Trees reported across Highway 61 by law enforcement from non-thunderstorm winds.
My guess is that "non-thunderstorm winds" might have been a gravity wave behind the previous heavy rain and storms.
As I was completing this post, the Sheriff in Cook County, MN just issued a travel warning urging people to stay off the roads in that county until crews can assess road damage and begin clearing roads.