00:00It is the last week of May, and historically, it's the last week of May that we see the most
00:06tornadoes across the country.
00:08Now, despite the fact, though, that we're going to see lots of thunderstorms here as we go through the middle
00:14and end of the week,
00:15take a look at all of the green across the country.
00:18I'd say about 60% of the country we're going to see thunderstorms, but severe weather is going to be
00:24limited, and here's why.
00:25While we are going to see lots of thunderstorms, what you need for severe thunderstorms is what we call wind
00:32shear.
00:33What is wind shear? It's the change in direction and or speed over a vertical or horizontal distance.
00:40What does that mean? An increase in wind with height.
00:43The stronger the wind shear, the more likely you're going to get severe thunderstorms.
00:48How do you get wind shear? With the jet stream, right?
00:52But take a look at the jet stream mid to late week. Here it is on Friday.
00:56Notice you have a dip in the jet stream across the western United States, but where we have all the
01:01thunderstorms across the plains and back into the southeast,
01:05the jet stream is so far north that you don't have any wind shear.
01:10That means limited severe weather the rest of this week and limited tornadoes.
01:15And by the way, that trend is going to continue.
01:17In fact, take a look at this. As we go through June, July, and August, while thunderstorms are on the
01:24increase, that's in the orange.
01:26Notice that tornadoes and severe weather is on the decrease.
01:29Why? Because as we head into the summertime, the jet stream lifts north, you have less wind shear, and you
01:37get less severe weather.
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