this concept. This is a predictive result that gives a certain lead time. With the Doppler velocity data, the meteorologist can see the downdraft and gust fronts happening, but since this a small scale feature, detection algorithms have been developed to point convergence and divergence areas under a thunderstorm on the radar display. Satellite imagery Most populated areas of the earth are now well covered by weather satellites, which aid in the nowcasting of severe convective and tornadic storms. These images are available in the visible and infrared domains. The infrared (IR: 10-13 µm) images permit estimation of the top height of the clouds, according to the air mass soundings of the day, and the visible (vis: 0.5-1.1 µm) ones will show the shape of the storms by its brightness and shadow produced. Meteorologists can extract information about the development stage and subsequent traits of thunderstorms by recognizing specific signatures in both domains. Visible imagery permits the most detailed imagery whereas infrared imagery has the advantage of availability at night. Sensors on satellites can also detect emissions from water vapor (WV: 6-7 µm), but mostly in the middle to upper levels of the troposphere, so thunderstorms are only seen after being well developed. It is, however, useful in convective storm prediction, as it illustrates the placement and movement of air masses and of moisture, as well as shortwaves and areas of vorticity and lifts. Severe storms have a very strong updraft. The rising air parcels in that column accelerate and will overshoot the equilibrium level (EL) before being pulled back by negative buoyancy. This means the cloud tops will reach higher levels than the surrounding cloud in the updraft region. This overshooting top will be noticeable by a colder temperature region in the thunderstorm on infrared images. Another signature associated with this situation is the Enhanced-V feature where the cold cloud tops forming at the overshooting top fan out in a V shape as cloud matter is blown downwind at that level. Both features can be seen on visible satellite imagery, during daytime, by the shadows they cast on surrounding clouds. In multicellular storms and squall lines, the mid-level jet stream is often intersecting the line and its dry air introduced into the cloud is negatively unstable. This results in drying of the cloudy air in the region where the jet plunge groundward. On the back edge of the line,