Ingredients are coming together for possible severe weather late this afternoon and this evening across portions of western, northern and central Minnesota.
A cold front approaching from the west along with stronger upper level winds will create atmospheric lift while southerly winds in the low levels of the atmosphere continue to advect moisture and instability north/northeast into the region. Wind shear is on the moderate to strong side this afternoon with mesoanalysis showing upwards of 50 knots of Effective Bulk Shear and 0-6 KM Shear, these values should hold fairly steady through the evening.
Strong to severe thunderstorms should develop by 6 PM over eastern North Dakota and northwest Minnesota, these storms are then forecast to move east/southeast through the evening, and with a strengthening low level jet out of the SSE, there should be good inflow to maintain these storms through the evening.
Storms are forecast to impact western portions of the Northland between 8-10 PM this evening, and are expected to reach northeast Minnesota including the North Shore, Twin Ports areas between 10 PM and Midnight. Storms are then forecast to impact most of northwest Wisconsin overnight (around Midnight or later)
Stay Weather Aware tonight as watches or warnings could be issued for some parts of the Northland! Note: The main severe weather hazards for tonight will be from damaging winds and hail. There is also a chance for a tornado this evening mainly around the Brainerd Lakes area.
The pink outlined area on the map below is where I think the greatest chance for a tornado will be this evening, the eastern portion of this risk area includes western portions of the Northland, roughly west of a line from Wirt to Brainerd.
Goes-16 water vapor loop showing a fairly strong system to mid July moving across the Northern Plains and into the upper Midwest today with stronger jet stream energy blasting ENE from the Northern Rockies to Northern Plains.
12z NAM 3km model simulated radar forecast valid from 7 PM this evening to 7 AM Tuesday.
And here’s the 20z HRRR model run simulated radar forecast valid from 7 PM this evening to 7 AM Tuesday. Looks pretty similar to the NAM model guidance.
Some more rain is possible in northeast Minnesota and northwest Wisconsin on Tuesday, and some thunderstorms are likely as well, especially over northwest Wisconsin where an isolated strong to severe thunderstorm is possible, mainly from the Hayward Lakes to Ashland areas and points east. It’ll be cooler on Tuesday due to the clouds and possible rain, highs are forecast to be in the 60s and 70s.
18z NAM 3km model simulated radar forecast valid from 7 AM Tuesday to 7 PM Tuesday.
On average we’re looking at a half inch to inch of rainfall across northeast Minnesota and northwest Wisconsin through late Tuesday afternoon, but localized higher amounts are possible with potential for up to 2 inches of rain in a few locations.
Computer models continue to indicate a wetter pattern setting up across the upper Midwest and Great Lakes including here in the Northland for the next 2 weeks with above normal precipitation forecast for the green shaded areas on the map.
Source: 12z European ensemble model 7.13.2020; https://weathermodels.com/
Thanks for reading!