Finding super cell thunderstorms and tornadoes
Even during peak season in Tornado Alley there are not thunderstorms everywhere and everyday. The conditions are favorable for severe thunderstorms to occur but it takes a few components in order for a sever thunderstorm to occur. These are the basic components for a tornadic thunderstorm, please recognize that this is very simplified and does not by any mean try to explain the full complexity of how storms are created.
Air moisture is an important component for severe thunderstorm. It brings energy into the storm and lowers the cloud base. The lower the cloud base, the more likely the storm is to produce a tornado.
Preferred value: Dewpoints over 60
Speed and angle at different levels
In order for the clouds to get an upwards, lifting motion there needs to be something in the atmosphere causing the air to move upwards. Over the plains this is usually caused by a a dryline, colliding fronts but can also be caused by mountains (common in Colorado).
Finding the storm
When a storm chaser or tour guide predicts where a storm may occur there are several models and free weather data services that provides this information.
The NOAA shows a broad area where they expect severe storms, large hail and tornadoes may occur based on their models. They also provide important information that are helpful for storm chasers, and the public. This, together with plenty other data, gives a very broad idea about which region(s) that may be of interest.
Once positioned in the region, radar images that provides information on the clouds in the area becomes more important. A popular software among storm chasers is the PC software GRlevel2 or GRLevel3.
An experienced storm chaser understands which storm to pick out for the day's chase, often the southern most storm in a line of storms.
Even though there has been great steps in the meteorology science and technology, it is almost impossible for weather forecasters to know if a tornadic storm actually has produced a tornado or just shows the radar signs of a tornado. Visual reports by storm chasers and trained storm spotters (from trained storm spotters) are crucial in order to know a tornado is actually on the ground or not. This information is extremely important for the people living in the path of the tornado.
During a chase a storm may appear on the radar as:
- Just a storm
- Hail marker
- Severe warned
- Rotation marker
- Tornado watch
- Tornado warned
- Rotating wall cloud reported / funnel cloud reported
- Tornado reported
Outside of the vehicle itself a storm chasing tour guide does not really need anything else than a laptop, some useful software and an internet connection. A HAM-radio is very useful in order to keep in contact with other staff and occationally other storm chasers in order to get update on storms.