00:00 It's time for a weather wise segment
00:02 where we take something complicated
00:03 in the world of meteorology and make
00:05 it simple for you to understand.
00:07 Let's talk about lake effect.
00:09 I think most understand the
00:10 concept of lake effect snow.
00:12 That is when you take cold air
00:14 and you bring it over warm water.
00:17 What do you end up getting?
00:19 Lake effect.
00:19 Here's how it works.
00:21 You have the warm lake waters.
00:23 Here comes the colder air aloft.
00:24 When you get that colder air
00:26 aloft over the warm waters,
00:28 you create instability warm at the surface.
00:31 Colder air aloft.
00:32 You get upward motion.
00:33 The water from the lakes.
00:35 That's moisture getting northward
00:37 you up into the atmosphere.
00:38 You form clouds.
00:40 You form precipitation in time and then.
00:44 You start getting the lake effect
00:46 snow and that moves inland,
00:47 so that's kind of the easy explanation.
00:50 I want to break it down a
00:52 little bit for you more.
00:54 Let's talk about the mechanics of it.
00:56 You need at least a 23 degree
00:58 Fahrenheit difference between the
01:00 lake water and the colder air aloft.
01:02 That's at around 5000 feet.
01:04 You need cyclonic winds at the surface.
01:06 I'll explain wind direction and
01:08 the fetch of that water determines
01:10 the location and the strength of the snow.
01:13 What in the world am I talking
01:15 about cyclonic curvature?
01:16 Well, if you think about it,
01:18 a lot of the cold air always
01:20 occurs on the backside of storms,
01:23 so you have large scale descent.
01:25 But you see all these winds are
01:27 moving counterclockwise here.
01:28 This is called cyclonic curvature.
01:30 This or cyclonic curvature.
01:31 This you get some low low areas
01:33 or small scale ascent.
01:35 Then the cold air over the warm waters.
01:38 Water temperatures in the 40s.
01:39 We're looking at temperatures at
01:41 5000 feet by the way in the teens.
01:44 And then you get the lake effect in
01:47 the West Northwest flow comes on in.
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