Fog is one of those things you take for granted.  It just kind of happens, like it did Sunday morning.  You rarely see anyone get upset with the meteorologist if he/she gets his fog prediction off, right? 

Around here, we see it more often than others.  Again, that's one of those things that you can thank the mountains for.  The picture at the head of this blog post is a good example of one way fog can form. 

In an idealized daytime situation, the valleys warm up more than the mountains because air escapes from the valleys towards the higher terrain.  So what happens during the night-time?  Almost the exact opposite happens in an idealized situation.  Air rushes down into the valleys from the higher terrain. 

1.  The air is cool (and stable) and condensed.  2.  The air (especially after a good rainfall, like we saw the other day) is moist.  What do I mean by that stable part? 

Just bear with me.  This chart may appear to be confusing, but I'll make it short, sweet and to the point!

The red line is temperature, and the green line is dew point.  When the dew point reaches the temperature, you have moisture (as is seen at the very bottom of the chart: the surface).  When the red line goes to the right in this chart, the atmosphere is stable.  That generally means that air can't lift.  So, if air is moist and can't lift, it just sits there.  BOOM...you have fog!

As the sun comes out, you warm the lower levels of the atmosphere and it becomes a bit more unstable.  That means air can lift.  Fog be gone! 

The next time you see widespread fog in this area, you may be able to find a reason why after reading this blog.  Hope you enjoyed reading it! 

Any feedback is always appreciated!

---Meteorologist Chris Michaels--- 

Facebook: Chris Michaels WCYB

Twitter: @WCYB_Michaels

Email: cmichaels@wcyb.com