Supercell thunderstorms that developed up in North Dakota this afternoon have merged and evolved into a damaging bow echo as they've moved east-southeast throughout the evening. This bow echo just crossed the Minnesota border, entering a severe thunderstorm watch area issued by the Storm Prediction Center. The watch is in effect until 200AM Central Time, and the main threats with this storm are damaging straight line winds up to 70 MPH, large hail (possibly golfball size or larger), and perhaps a spin-up tornado or two along the leading edge of the bow echo.
As I've stated before, Severe Weather Liveblog usually doesn't cover severe thunderstorms, but since this is a large and dangerous bow echo moving towards a heavily populated area (the Minneapolis/St. Paul metro area is home to over 3,000,000 people) it warrants coverage so that word gets out and Kossacks in the area know what's coming.
The newest updates will appear at the top of the information below the fold. Check back for new updates every 20-30 minutes as these move east for new updates, especially if you live in the threat zone.
As usual, keep politics, meta, pie fights and dickish comments out of here or you'll find yourself in the hidden comments. Several folks have questioned the reasoning and validity of this promise, and G2Geek gave a pretty good explanation.
Updates
Update 3 1012PM CDT
Here we go. 75MPH winds have been reported by law enforcement with this line of storms about to go into Minneapolis. Brace yourselves.
Right: Base reflectivity (precip). Left: Wind velocity
Update 2 954 CDT
Sorry about the absence of updates, I got really tired and didn't feel well for a while there. I lay down in bed for a little while and I'm fine now. Go figure.
The storms are about to go right through MSP, right on schedule. Here's the wind velocity image, showing the intense winds (green bow on top right) about to enter the Minneapolis metro area. This line will have up to 70 MPH winds as it moves through, so be prepared.
Update 1 805PM CDT
Here are some of the reports from today, which will open in Google Maps. Zoom in and click a W, H or T to view the wind, hail or tornado reports, respectively. There have been numerous 60-70 MPH wind reports with this bow echo, some of which have caused structural damage.
Right now, there are numerous severe thunderstorm warnings encompassing almost all of central-western Minnesota, and there are two tornado warnings along the leading edge.
There is some strong rotation along the edge of the storms near Dawson, MN, which could see a rain-wrapped tornado within the next few minutes. Tornado warning out for Lac Qui Parle County, MN for this storm.
The other tornado warning is for Swift Co, MN, for more rotation along the leading edge of the storms. A funnel cloud was spotted with this storm, and the funnel cloud/possible tornado is expected to be near Starbuck, Sedan, Belgrade, Georgeville, Gilchrist, Grove Lake, Brooten and Padua over the next 30 minutes, as the storm moves east at 60 MPH.
Initial Post @ 802 PM CDT
Here's the initial radar from the area, with my forecast for where the bow echo will be by 9PM and 10PM. It's moving east-southeast at 60 MPH, so I think it will reach the MSP metro area somewhere between 930PM and 1030PM, so I split the difference on the map. Either way, be ready for bad storms tonight.
And here's the severe thunderstorm watch: