What's up with the fog?

A Dense Fog Advisory will continue through noon today for almost all of southern Wisconsin and northern Illinois.  Low level moisture has been very slow to leave the past couple days and now that high pressure has moved into the upper Midwest winds have remained fairly calm and we haven't been able to mix our atmosphere very well.

This is the upper level sounding (snapshot of the atmospheric profile) from Davenport, IA this morning.  The red line indicates temperature and the green line indicates dew point.  On the right hand side is the wind, both the direction the wind is coming from and the speed of the wind.  Notice how the temperature and dew point line are almost on top of each other in the lowest levels of the atmosphere.  This shows a very saturated layer.  Also, notice how the temperature line increases with height.  The temperature readings are on the bottom of the graph and in Celsius.  Just like yesterday morning, there is an inversion in our atmosphere and with very little wind and light wind speeds we won't be able to bring down the drier air from above and this is probably going to keep the fog around for a little while.  This will also keep temperatures down today as we've been stuck at a chilly 29° the past several hours.  Once the fog does lift we won't see much sun today thanks to cloud cover overhead.