Here’s the discussion from SPC this afternoon:
...UPR MS VLY/WRN GRT LKS THIS AFTN THROUGH TNGT...
CONSIDERABLE CLOUD COVER REMAINING FROM OVERNIGHT CONVECTION WILL CONTINUE TO THIN ACROSS ERN MN/NRN WI INTO THE AFTERNOON ALLOWING STRONG HEATING/DESTABILIZATION TO OCCUR AHEAD OF THE COLD FRONT ACROSS THE EXPANDING WARM SECTOR. THE COMBINATION OF STEEP MID LEVEL LAPSE RATES AND DEWPOINTS RISING TO AROUND 70F WILL LEAD TO MDT/STG INSTABILITY BY MID AFTERNOON WITH MLCAPES TO AOA 3000 J/KG. WITH THE PRONOUNCED EML ACROSS THE AREA...TIMING OF SURFACE INITIATION OF SEVERE THUNDERSTORMS IS A CONCERN AND APPEARS SHOULD BE DELAYED TO MID OR LATE AFTERNOON. LACK OF ANY SUBSTANTIAL UPPER FORCING WITH THE SWLY FLOW WILL LIKELY REQUIRE FULL HEATING TO OVERCOME THE CAPPING NOW IN PLACE. ONCE STORMS FORM...40-50 KT DEEP WSWLY SHEAR AND STEEP MID LVL LAPSE RATES SHOULD SUPPORT SUPERCELLS/SUSTAINED STORMS WITH LARGE HAIL...DMGG WIND...AND POSSIBLY TORNADOES. THE LATTER THREAT SHOULD BE GREATEST IN NRN WI...WHERE LOW LVL SRH SHOULD BE MAXIMIZED IN ZONE OF LOW LCLS NEAR THE WARM FRONT. BY EARLY TONIGHT...EXPECT STORMS TO MERGE INTO ONE OR MCS/S. WIND PROFILES AND THERMODYNAMIC ENVIRONMENT APPEAR FAVORABLE FOR BOWING SEGMENTS WITH AN INCREASING THREAT DMGG WIND IN WI AND POSSIBLY NRN MI.
As you can read there is a chance for stuff to form in northern Minnesota and Wisconsin, where there are two tornado watches currently. Then as the storms merge, a large complex of thunderstorms with high winds could form and move into Upper and Northern Lower Michigan. The News story from NWS Gaylord has when we are expecting the worst stuff and what it will be: Some thunderstorms tonight will have the potential to be severe, mainly between 10 pm and 6 am. The main severe weather threats will be:
- Damaging winds in excess of 70 mph
- Hail quarter size or larger
So far, the there are thunderstorms are forming, but no complex as of yet.