What is weather?




The state of the atmosphere.

So the atmosphere looks like this:

Image result for layers of the atmosphere

As you can see, the layers are determined by what happens to the temperature.  Why does the temperature change with each layer?


Image result for adiabatic temperature change

The change in temperature due to a change in pressure.



The sun's incoming energy drives weather, so let's look at InSolAtion (incoming solar radiation):

Image result for insolation

What are the factors influencing insolation absorption?



Image result for insolation

Color, texture, sheen, etc.


Heat moves around the Earth via conduction, convection, and radiation:

Image result for heat transfer, earth


Convection of heat leads to pressure differences:

Another way to look at heat in the atmosphere is by looking at the air pressure.

Which would weigh more, hot air or cold air?

So which would have greater pressure?

Air pressure tells you about the temperature of the atmosphere and that has effects on everything.

Image result for atmospheric pressure


A lot of weather is the interplay between temperature and water in the air.

Water in the air is called humidity.

Absolute humidity is the ratio of water vapor to gas molecules in the air, ranges from 0 to 30 g/m3, and is mostly useless information.

Relative humidity is the ratio of water vapor in the air relative to the amount of water vapor that can be in the air and is vital information.

Relative humidity changes with the temperature since the about of water vapor that can be in the air changes with temperature:

Image result for relative humidity

This means that if you heat up an area, the air gets relatively dryer.

Conversely, if you cool an area down, the air gets wetter and wetter until...

...dew point: the temperature at which the relative humidity = 100%.

If you cool air down past the dew point, the excess water condenses on any nuclei it can find and you get dew, frost, rain, snow, glaze, sleet, drizzle, clouds, fog, hail, etc.

Image result for relative humidity, dew point


The condensed water forms clouds:

Related image



Uneven heating leads to uneven pressure which leads to winds:

Image result for cause of winds

Image result for cause of winds

Image result for pressure, winds


If air sits over an area long enough, it takes on properties of that area which we call an air mass:

Image result for air mass

Where air masses come together, there are "fronts":

Related image

These fronts have weather patterns that accompany them.

Image result for cold front

Image result for warm front


Sometimes things get scary/exciting:

Image result for thunderstorm

Image result for tornado

Image result for hurricane

Thunderstorms, tornadoes, and hurricanes:


Climate is the average weather an area gets over a long time (30 years).

What are the factors influencing an areas climate?

Climate change!



Predicting weather...