As I reflect, it was Severe Weather Preparedness Week— March 6-10, 2023. We have already had severe weather this year, but it will become more frequent now that spring is around the corner. Sometimes when thunderstorms are forecast, you will hear weathercasters talking about the atmosphere being very unstable. What does that mean? Rising air cools For thunderstorms to form, air must rise. As air rises, it expands because air at higher elevations has less air pressure. The expansion of rising...

We are bound to have fog from time to time. I still remember when I was in my late teens and insisted on going to see some friends when I could barely see the edge of the road. My parents were not happy. Some areas, such as San Francisco or London, have fog more often. The cause of fog can depend on location. Radiation fog The most common cause of fog in Illinois is when there is a lot of moisture in the air on a clear, calm night. This creates what is known as radiation fog. When you hear...

California has recently been slammed with extreme rainfall and snow in the high elevations, along with high winds. Media have attributed these events to an atmospheric river, but what does that mean? What is an atmospheric river? The ones that affect California occur when the polar jet stream splits over the Pacific Ocean, with part of it diving in a big U-shape down to near Hawaii. The same polar jet stream affects us in Illinois during the winter. As it dives south, huge amounts of water...