Weather “U” Lesson 11 Severe Weather

So have you watched the local weather station or turned in to a weather report and they said you area was under a Thunderstorm Watch. What does this mean? Here we can see that when a Watch is issued it means that the conditions are favorable for Severe Weather Events. Where as if we have a warning issued this means the events are occuring or likely to occur real soon. Now you know the basic difference of the two.

So what makes thunderstorms occur? Here are a few key items that need to be looked for. First, moisture the air needs moisutre and there are sources such as large lakes,residual moisture from past rain, or oceans these are all good examples of moisture. Secondly, you need to have upward vertical motion. This is best described as the power of air to rise up in the sky.  The easiest way to accomplish this is by a warm surface, because warm air loves to rise vertically, also later on we will learn about troughs in the upper levels and how they can also create that upward motion. Lastly, we need Divergence in the upper levels this is created by that upper level trough again. So if you are able to get these three things working together you have started the Thunderstorm Formula.

Now lets look at some componets that come with thunderstorms.  Starting with Figure 6-1 we see lightning most thunderstorms will produce lightning as this is caused by the sudden heating and expanding of the sky. Next is thunder itself which is the by product of the lightning when you watch a thunderstorm you notice that after a flash of lightning comes thunder. Also did you know if you count how many seconds after lightning occurs before the rumble of thunder you can determine a rough estimate in miles of how far away the storm is, 1 second is about 1mile. The next feature is Hail and we all know this can hurt, thunderstorms are known for producing hail of many sizes, so how does the hail get larger? The size of the hail depends on how long it remains in the cloud, the longer in the cloud the larger it will be when it falls. Fourth are a very unique feature and that is mammatus clouds which form on the outer edge of the thunderstorms anvil top. Next is snow yes that is right you can have a Thundersnow storm occur just ask certain weatherman that get stuck reporting in these type of events. The next feature is called a gust front and this is very important to because this cloud has a horizontal roll to it in the sky and brings very strong winds that can exceed 65mph it is usually very short lived event. The next feature is the Wall Cloud and this forms when all the air starts circulating in the atmosphere inside the cumulus-nimbus cloud, one of the developing stages of the Tornado. And of course lastly you can get Tornadoes, there is more to follow on them below.