Weather fronts ???

Question

Where are the particular regions of the world that frequently experience such air mass collisions and frontal weather? Is the weather in these regions regular and predictable, or highly variable?

Answer 1

The equator is a region of equatorial lows. The poles are region of polar highs. That's because warm air rises giving place to low pressure and sinking air increases the pressure.

And the air would move from equator to poles if it wasn't that ... the earth spins and due to the the Coriolis effect, in the northern hemisphere the equatorial lows falls back, spining clockwise, creating high pressures at about the latitudes 30 N and S.

Between those and the pole highs, a front is formed since warm moist air don't mix very well with cold dry polar air.

That front is at about latitude 60 N and another one at 60 S.

This where many lows are born because, as the warm moist air climbs over the dry and cold one, it cools down, create clouds, rain as the lows are generally moving eastward, taken by the Jet Streams right above the fronts.

The weather in those frontal regions can best be explained by some statistics from Britain: If it rains, there is 70% chances to be sunny the day after. if it is sunny then the chances are 70% that it wil rain the day after.

The reason is that lows are moving at a speed of about 20 to 25 knots and that between each low there is a high rigde and that it takes about 24 hours to go from a low to a high ridge.

Note that this is an average. Sometimes a stationary high comes in and brings sunny weather for several weeks. That happens when the Jet Streams are weak; on the average, three times per year.