Wind and Lake Breezes

The KSL weather website says the wind is N 25 mph, yet in the description of the day's weather it talks, correctly, about the winds coming from the south. Looking out my window, I see all the flags, at least in the downtown area, blowing from the south. This isn't the first time I've seen the KSL weather report claiming the winds to be the direct opposite of what they were. What gives? Am I reading something wrong? John G.

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Great question John. It's one of two things, it's either a bad anemometer (which does happen) or it's a lake breeze. When we start to get warmer in the springtime we have to deal with a lake breeze. Ok, we know that sometimes when we go to the ocean or the lake, we feel a breeze, what's that about. To understand lake breeze, we need to look at some diagrams.

The lake breeze is a circulation which happens in the afternoon, in some places it's like clockwork. Along the shores of the Great Lakes you get lake breezes in the summer almost everyday.

Let's think about a typical day. And if you really want to understand this even more, get a pen and paper going on. In the morning when we wake up, which is colder during the spring months, the lake or the land? Usually the land. So, let's draw a diagram with some grass and some lake. Label the night time and which is colder. In fact, I'm feeling so artistic today that I will create a paint file with the drawings. Click those over there.

So at night, the lake is warmer and you get this circulation called a land breeze. During the daytime, the land gets warmer than the lake. Warm rises. So the warm air over the land rises and creates the lake breeze circulation. So often times in the afternoon we get a lake breeze at the airport, sometimes we'll get it downtown but often the airport observation and the downtown one can be different.

Answered by KSL Meteorologist Dina Freedman.