Weather Notes

“The only thing predictable about life is that it is unpredictable “The only thing predictable about life is that it is unpredictable.” -Remy Ratatouille

What is an air mass? An air mass is a huge body of air with uniform temperature, pressure, and humidity (moisture).

There are four types of air masses which combine to create the different climates of the United States.

Tropical: warm air coming from the tropics, with low pressure.

Polar: cold air coming from the poles, with high pressure.

Maritime: moist, humid air coming from over the ocean.

Continental: dry air coming from inland regions.

See how the different combinations of air masses give areas their typical weather type?

Maritime Tropical air masses are what makes the South so warm and humid!

Maritime Polar air masses are what makes Seattle so cold and rainy!

Continental Tropical air masses are what makes the Southwest so hot and dry!

Continental Polar air masses are what make the northern states and Canada so bitterly cold!

In America, the Prevailing Westerlies keep most air masses moving from West to East. They turn because of the spinning of the Earth. This is called Coriolis Effect (reasons for Prevailing Westerlies and reason why Earth spins)

What happens when two air masses run into each other? a FRONT occurs when two air masses collide (like a battle front)

There are four types of fronts, all of which tend to cause clouds and rain. The type of front depends on the air masses and their speed. The faster moving air mass always wins the front!

Cold Front: fast moving cold air mass meets slow moving warm air mass. The warm air gets pushed up out of the way, so the cold air stays underneath.

Cold fronts usually cause sudden weather changes and storms. Affects: After the cold front passes, it is clear and colder out.

Warm Front: fast moving warm air mass meets slow moving cold air mass. The faster moving warm air pushes the cold out of the way!

Warm fronts causes slow forming storms that stay longer. Affects:After the warm front passes, it is warmer and humid air.

Stationary Front: Both cold and warm air masses are moving slowly. Cause: Neither air mass is moving fast enough to push the other out of the way.

The Affects: the front gets stalled and brings many days of rain, fog, clouds, or snow.

Occluded Front: When a warm air mass gets caught between two cold air masses. (Occluded means blocked)

Affects: Occluded fronts can bring clouds, rain, and even snow.

The two factors that affect the weather the MOST are: 1) Temperature 2) Altitude

There are two main factors that decide what air pressure we feel. #1 = Altitude: how high up in the atmosphere you are.

Oxygen is heavier than Nitrogen, so it sinks to the bottom of the atmosphere. That means that the lower you are, the more weight is pushing on your head!

This means: the less oxygen there will be to breathe the higher you are! (This is why people take oxygen tanks when climbing Mt. Everest)

#2 = Temperature: When it is cold, the oxygen will huddle together, putting even more molecules on your head! Cold Hot High Pressure Low Pressure

High Pressure (cold) Low Pressure (warm) To equalize the amount of pressure, oxygen will move to evenly distribute it. High Pressure (cold) Low Pressure (warm) We can see and feel the oxygen moving...

Air moving from an area of high pressure to an area of low pressure is WIND!

With temperature, pressure, and wind comes all sorts of crazy weather.... floods winter storms thunderstorms hurricanes tornado