/Issued 5:28 PM CDT, Tuesday, July 25, 2017/
Radar image and surface analysis from 5:15 PM CDT, July 25, 2017.
Counties shaded in blue=Severe Thunderstorm Watch until 11 PM tonight, this includes portions of central and southern Minnesota.
At 4 PM there was a warm front across southern Minnesota while a cold front extended from northwest Minnesota into east central South Dakota. A more humid day ahead of this system today with late afternoon dew points ranging from the 60s in northeast Minnesota and northwest Wisconsin with low to mid 70s in central/southern portions of Minnesota. The atmosphere has become very unstable this afternoon with an area of 2000-5000 j/kg of surface-based CAPE covering the southern half of Minnesota while in our neck of the woods most of the instability is elevated with most-unstable CAPE values of 1000-2000 j/kg. Temperatures aloft are quite warm with 700mb temperatures of +10 to +12 degrees C, this is leading to a capped atmosphere in our local area thanks to the cloud cover and limited heating near the surface. Highs in the Northland were in the 70s today with 60s near Lake Superior, but where the sun has been out, temperatures warmed well into the 80s to lower 90s this afternoon in southern Minnesota.
The focus for tonight remains on the potential for scattered showers and thunderstorms in northeast Minnesota and northwest Wisconsin. It’ll likely be a few more hours before convection gets going, and once it does, it looks like most of the stuff would remain in east central Minnesota and northwest Wisconsin, and up toward the Highway 2 corridor in northeast Minnesota. A few of the storms could become strong to severe with large hail and strong winds being the main threats along with torrential downpours and lightning. Note: With PWATS ranging from 1.50″ to nearly 2.00″ in southern portions of the Northland, the potential is there for localized flooding if thunderstorms begin to train over the same location for a couple of hours later tonight.
Northern Minnesota, including the Borderland and Iron Range should only see a few spotty showers or thunderstorms tonight as the cold front moves through this evening.
Lows tonight will mainly be in the 60s, but a few locations could dip into the 50s up north and near Lake Superior.
Wednesday will feature mostly cloudy to partly cloudy skies with a risk for mainly morning showers or thunderstorms in parts of northwest Wisconsin. Cold front will exit to the south/east with a less humid airmass spreading north-south over our area during the afternoon hours. Highs Wednesday in the 70s and 80s.
A few showers or thunderstorms are possible Thursday as a potent disturbance with cold temperatures aloft move southeast and through the Northland.