Friday, March 9, 2007

The Three Main Ingredients for Severe Storms

Our discussion into Severe Storm Forecasting has to start somewhere, so let's begin with the 3 Main Ingredients for thunderstorms. Thunderstorms, by the way, are also referred to in scientific papers as "deep, moist convection" (DMC, for short). So there's our first acronym! DMC = Deep, Moist Convection = thunderstorm.

So what are the three main ingredients? In his published paper (Weather and Forecasting 1995, entitled "Severe and Convective Weather: A Central Region Forecasting Challenge") Richard P. McNulty, a meteorologist in the National Weather Service's Training Center says that those three ingredients are:
Convective instability, moisture, and a source of lift


Put those three ingredients together and you have the makings of a thunderstorm. Whether it becomes a severe thunderstorm depends on the amount (or degree) of those ingredients (and, for example, how long-lived the storm is in such an environment. A severe storm that moves into drier air is not going to remain severe, for instance.

For a good look at these three ingredients (explained briefly with illustrations) see the JetStream page: http://www.srh.weather.gov/srh/jetstream/mesoscale/ingredient.htm We'll look at each of those three main ingredients in more detail as we go along.

No comments: