The system moves in a clockwise rotation similar to a whirlpool. These new air waves bring hot air from the Caribbean Sea and the Gulf of Mexico into southern Michigan and the most of the Midwest. Along with this hot air comes a high percentage of evaporated water in the air compared to what the air can contain - humidity. But when the humidity level reaches 90 percent, the air will feel heavy, muggy and wet. When relative humidity reaches the 90 percent range it will often make the temperature feel 10 degrees higher, making a 90 degree day feel like the temperature is in the mid-100s.
High humidity has a stagnant oppressive feel to it due to a lack of air movement in the atmosphere.
The low pressure area that has lowered over us also doesn't allow much wind to break through. Fortunately, Michigan is at the edge of this large low pressure system. This allows cold fronts to move through the area and bring much needed wind from the down drafts of storms, putting the sluggish air in motion. Rain also accompanies the cold fronts that have kept Michigan out of a national drought that has gripped parts of the South, Midwest and even as far north as the Ohio Valley. Along with grounds crew like Raffo working in the shade with running water on hand, many other University employees have had to seek out the cooler aspects of their jobs.