Weather Note Check You have 15 minutes to create your posters

Climate is how the weather usually is in a particular area Climate is how the weather usually is in a particular area. For example, Austin is usually very hot in the summer, and we have mild winters. Weather is what it is like outside right now. For example, a cold front came in this morning, and now I want to stay inside. But what causes our weather to change?

The WIND causes our weather to change What causes wind? diferences in pressure

What does that mean? It means, that wind is produced by the uneven heating of the earth’s surface by the sun (remember, the Earth is tilted, so we don’t all amount of sun) Differences in air temperature cause convection currents in the air (warm, less dense air rises, cool denser air sinks) This movement of air is wind.

Wind is the force that moves Air Masses around the globe Our weather depends a lot on the wind. Wind is simply the movement of air, but what causes it and how does have such an impact on our weather? Wind is the force that moves Air Masses around the globe The movement of these Air masses causes Changes in weather 5

What are Air Masses???? Large areas (blobs) of air that have the same weather, temperatures and humidity Weather changes occur with changes in air masses

What Are Fronts??? As air masses are moved around by the wind they interact, meet-up, and displace each other. Fronts are the boundary between two air masses They bring changes in the weather Fronts are named for the air that is behind them

Cold Front Cold dense air pushes warm air out of the way Cold fronts move very quickly and bring short periods of rain/thunderstorms Lower temperatures are behind the front SYMBOL – the direction of the “arrows” points towards the direction the front is MOVING

Cold Front Diagram

Cold Front

Warm Front Warm air moves up the cold front as it slowly displaces the cold air Warm fronts move slowly, and bring many days of steady precipitation Higher temperatures are behind the front SYMBOL – direction of “half-moons” is the direction the front is moving

Stationary Front The air from the warm front and cold front meet, but do not move These fronts have the same weather as warm fronts SYMBOL – warm and cold fronts are moving in opposite directions, thus making a stationary condition

High Pressure System In a high atmospheric pressure system the atmospheric pressure of the air is higher than that of the air around it. (It’s less dense) High atmospheric pressure systems are marked by an H on a weather map They mean clear weather.

Low Pressure System In a low atmospheric pressure system the atmospheric pressure of the air is lower than the air around it. The air is more dense. Low atmospheric pressure systems are symbolized by an L on a weather map. They mean storminess and precipitation

Let’s see it on the map! Stationary Front Cold Front Warm Front

All thunderstorms produce lightning Lightning is the discharge of huge amounts of static electricity (think of walking across a carpet in your socks and then touching something-ZAP) Thunder is the result of the air quickly expanding from the heat of the lightning bolt You cannot have lightning without thunder!!

Measurements wind speed air pressure anemometer barometer [ORIGIN from Greek anemos ‘wind’] [ORIGIN from Greek baros ‘weight’]