Hazy Sunday sky

The fog Sunday morning didn't last long, but skies remained cloudy through most of the afternoon.  It was only until mid to late afternoon that the cloud cover began to break, and temperatures warmed into the middle 70's.  But, did you notice when the cloud cover started to clear, the sky above looked hazy? 

Part of that has to do with the wildfires out west.  The smoke became caught in the jet stream that is now moving through Midwest.  And while health related issues are not anticipated, the haze/fog/smoke could be lasting a little while through Monday because of what else is going on within the atmosphere.



This image to the left is the latest forecast sounding from the Quad Cities National Weather Service.  What it shows is the temperature and dew point profile from the surface, all the way up to the top of the atmosphere (or until the weather balloon breaks).  What sticks out to any meteorologist when first looking at this sounding is the temperature inversion around 900mb (a little over 3,000ft above).  What this shows is a warmer layer present at that height.  An inversion acts like a lid.  It's hard for things to get past the inversion.  This was part of the reason why the clouds were slow to clear Sunday.  And once they did, any moisture still present in the atmosphere became 'trapped'.  And with the inversion, or lid, on the atmosphere low level moisture will remain in place once again Sunday night.  This will lead to locally dense fog once across parts of Northern Illinois and Southern Wisconsin.

The Quad Cities National Weather Service has already issued a Dense Fog Advisory for Whiteside County beginning very early Monday morning.