11:10 pm. Wider scan of radar, showing the most intense storms approaching Rochester…..storm risk has diminished in the immediate metro area, but the threat is not over just yet. Tornado watch remains posted until 2 am. Flood advisory still in effect for the expanded metro, flash flood watch through midday Thursday.
10:13 pm. Wider scan showing severe storm cluster over southeastern MN. The purple polygons are the projected (NWS) paths of these severe storms. No tornado warnings posted…risk of pea to quarter size hail, wind gusts over 60 mph with storms near Rochester, and moving in the metro area. Tornado watch posted until 2 am Thursday. Severe storm warning for Carver, Hennepin and Scott co. until 11 pm.
10:00 pm. 3-D volume scan showing most intense storm over Carver county, where weak rotation is still being detected. Strong wind shear (estimated helicity right now is about 450-500) makes Twin Cities area ripe for rotating “mesocyclones” capable of an isolated tornado. Most of us will just see heavy thunderstorms and some minor flooding problems.
9:57 pm. New severe storm warning for much of Hennepin, Scott and Carver co. until 11 pm. Winds gusting to 60 with pea-size hail, isolated tornado can’t be ruled out. A flood advisory is posted for the Twin Cities….rainfall amounts of up to 2″/hour may cause flooding of streets, streams and some basements through the wee hours of the morning.