Advection

Get used to the word "advection", you'll hear it a lot. Advection is the attempted transport of an atmospheric property horizontally from one place to another by the wind. Here, I'll be talking about temperature advection. In most areas of the United States, the temperature tends to increase if the wind is from the south, and the temperature tends to decrease if the wind is from the north. It's only logical: if it's warmer to the south and the wind is from the south, it ought to warm up.

Of course, if temperatures are not warmer to the south, the mere existence of a south wind will not cause the temperature to rise. Similarly, if the air is warmer to the east, an east wind will cause the temperature to rise.

Instead of relying on rules for wind direction, which work only part of the time, meteorologists look directly at the pattern of temperature and wind on weather maps. From the maps, they can tell where the air is warmer and cooler (and by how much) and which way the wind is blowing. If there's warm advection (wind from a warmer area), the temperature ought to rise, and if there's cold advection (wind from a colder area), the temperature ought to fall.

Now remember what I described earlier about air masses and fronts. Where do you think temperature advection will tend to be stronger?

1. Within an Air Mass
2. Within a Front

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