Weather “U” Lesson 12 Winter Weather

The first type of winter precipitation that we will identify is Freezing Precip. On the left you see a powerline that ran into the freezing rain scenario. On the right we have what is called a vertical profile of the atmosphere above this poweline or very close. On the graph to the right we have basic things identified such as the height in MB. and the temps. If you see the solid line this is the freezing level with height. Now if you look at the light blue line this repersents our air temp with height. You will notice that it crosses to the right of the red line indicating that  the precip is melting as it falls. However right before the ground you notice that it goes back below freezing. This causes us to have freezing rain.

The next profile we will look at is Snow. As you can see the lines are the same as from above. So if we take a look at our air temp we notice that it never goes above the red freezing line. This lets us know the precip should remain frozen all the way to the surface. That is why you will most likely see snow.

Now lets look at a few different condtions that can lead to heavy snowfall events. At Location #1 in the upper right you notice that we marked a spot above the warm front this is our location for heaviest snow just north of the warm front.  Now take a look at Location #2 and you see that we have moved it to near the purple front which is called an occluded front. On the poleward side of the occluded front we will also find the chance for heavy snowfall. Moving on to Location #3 This is a place downstream of the lake that has strong cold winds blowing over the warmer water and pushes the heavy snow to the other side of the lake “Lake Effect Snow”. At location #4 we are watching what is called orographic lift. On the windward side of the mountain we see heavy snowfall amounts because the snow is unable to go up and over the mountain.

Here are a few common winter storm tracks that impact the United States. If you read the information below the photos you can see what type of weather each brings to various places in the US.

Now let’s look at a few Review Questions from this chapter.

Enjoy the weather!