LJWorld.com weblogs Lawrence Weather Watch
A recipe for fog
Fog is common in low-lying areas, especially river valleys. The Kansas River Valley is certainly no stranger to fog, either. One type of fog we often see is called "radiation fog". I have an ideal recipe in my hand for this type of fog.
These three ingredients make the best "radiation fog:"
1) Clear skies
Temperatures cool at night. When skies are clear, they can cool quickly. Skies are expected to be clear through Friday morning. Temperatures will cool accordingly.
2) Temperatures that near the "dewpoint temperature"
The "dewpoint temperature" is a measure of moisture. What you need to know, is that when the "dewpoint" is close to the actual temperature outside, then there is a good chance that fog can form. We often see these two temperatures get close together after recent rainfall. Since we just had a lot of rain, we have a good chance at these temperatures being close together through Friday morning.
3) Light winds
Winds greater than roughly five or ten miles per hour are just strong enough to mix in some dry air (keeping it somewhat warmer, too). Drier air will help to keep the "dewpoint" from being close enough to the actual temperature such that fog will be less likely. When winds are light, as they are expected to be through Friday morning, then we don't have to worry about dry air slowing down fog formation.
With clear skies, light winds, cool temperatures and recent rainfall, it looks like all the ingredients are in the weather mixing bowl for fog formation through Friday morning. Make sure you give yourself a few extra minutes to get to work or school, Friday morning. Plan on allotting extra room between you and your fellow driver, too.
Oh, and don't forget the shades, either. Why the shades with all this fog potential? It looks like the warm, late-summer Kansas sun will burn off that fog by late Friday morning. You will want those shades for the commute home from work or school.