Welcome to Cara’s Weather Corner – your weekly weather forecast by OU meteorology student and Tulsa Partners intern Cara Vanarsdel!
This week will still be nice and warm, however, it’s a tad bit more cloudy than the past couple weeks. Slight chance of showers and thunderstorms for this morning and afternoon, with a high in the lower 90s. Tuesday and Wednesday will give us some more sun, but the chances of thunderstorms increases drastically starting Wednesday night and lasting through the weekend. Which means… July 4th might be a little rainy! Highs for the week will still stay in the lower 90s and then hit around the upper 80s on the rainy days.
Because this week might bring some thunderstorms with it, I thought it would be a good idea to talk a little bit about how thunderstorms actually form, and why we get a storm instead of just a calm rain. Haven’t you always wondered?
So here’s today’s “Fun Fact”: Thunderstorms require three ingredients for their formation: moisture, instability, and a lifting mechanism. Here in Tulsa we get our moisture mainly from the Gulf of Mexico and the Atlantic Ocean. That water is also normally pretty warm, and evaporation is higher in the warm ocean, so more moisture is being put into the atmosphere. That is why the southeastern U.S. gets much more precipitation compared to the same latitude in Southern California. Instability is the second ingredient. Air is considered unstable when it continues to rise after given a nudge upward. When air rises, it cools, and allows water to condense and form the tall cumulonimbus clouds that are the beginning signs of a thunderstorm. The last ingredient is the lifting mechanism; the initial “nudge” upward. Some of the sun’s heating of the earth’s surface is transferred to the air, which, in turn, creates different air densities. The tendency for air to rise increases with decreasing density. This difference in air density is the main source for lift and is accomplished by several methods: differential heating (for example, a grassy field will heat much slower than a paved street), fronts, drylines, and outflow boundaries, and also terrain (like mountains, for example).
How does it start, how long does it last, and why/how does it end? Well, now that you know the ingredients for a thunderstorm, visit this link for the National Weather Service’s take on the Life Cycle of a Thunderstorm!
Thunderstorms (and other severe weather) are much more fascinating after finding out exactly what it takes for one to form, and what happens during the storm. For interesting information on hail, damaging wind, and tornado formation, visit the National Weather Service’s JetStream – An Online School for Weather.
All graphics retrieved from the National Weather Service Tulsa.