A large trough of low pressure continues to spin across the Northern Rockies and Northern Plains today, this system will move east and through the upper Midwest on Saturday creating more lift in the atmosphere which should lead to multiple rounds of showers and thunderstorms through Saturday night.
Goes-16 water vapor loop from Friday, August 27, 2021.
Much of the Northland remains in a cool and stable air mass well north of a warm front which was down along the Iowa-Minnesota border where its much warmer and more unstable today, the result of this is for mostly light rain and little if any thunderstorm activity in northeast Minnesota and northwest Wisconsin today, while heavier rain and thunderstorms occur farther south in a more unstable environment.
The setup for tonight and Saturday will find the warm front well to our south this afternoon lifting slowly N-NE, with this front possibly making it into southern portions of the Northland on Saturday before a cold front pushes east and through the area Saturday night.
We should see an increase in mostly elevated CAPE in the Northland tonight and Saturday as a warm front lifts closer to our area, with the highest values of CAPE likely setting up from east-central Minnesota into northwest Wisconsin where values of 1500-2500 J/kg are possible, this combined with ~30 to 40 knots of wind shear will increase the potential for some strong to severe thunderstorms across southern portions of the Northland on Saturday.
Scattered to numerous severe thunderstorms are possible Saturday over east-central Minnesota into much of northwest Wisconsin (mainly south of Duluth and Superior), while isolated severe thunderstorms are possible farther north across northern Minnesota, the North Shore and Arrowhead.
Main threats from severe weather on Saturday include
Large hail of 1.00″ to 1.50″ in diameter (Quarter size to Ping Pong ball size)
Damaging Winds of 60-70 mph
An isolated tornado
Stay Weather Aware on Saturday!
Doesn’t look like will be seeing much rain or thunderstorm activity in northeast Minnesota and northwest Wisconsin tonight with mainly just some patchy light rain and drizzle expected, but on Saturday and into Saturday night there is potential for a couple rounds of showers and thunderstorms to move across the Northland. Rain moves out of the area early Sunday morning.
18z simulated radar forecasts valid from 7 PM Friday to 7 AM Sunday.
NAM 3km model
There is a large temperature gradient evident today, with 60s in northern Minnesota, while 90s and even some 100 degree temperatures were found across the Central Plains.
There has been some rain falling across northern Minnesota today, and it’s this area of the state which is in Exceptional and Extreme Drought. However, there really hasn’t been much rain yesterday or so far today over the Greenwood fire area (pink outlined area on map) which is sitting at 25,991 acres as of 4 PM Friday, but the good news is there shouldn’t really be much additional growth in the Greenwood fire through Sunday morning due to cooler temps, cloud cover, higher humidity and some more rain at times.
Computer models continue to show upwards of an inch or more of rain by Sunday morning across northwest Wisconsin, northeast and eastern Minnesota with even higher amounts possible in thunderstorms. Around a quarter to half inch of rain is possible in northern Minnesota. Will see what happens.