Learning objectives Why do geographers study the weather? What is the difference between 'weather' and 'climate‘? Climate graphs Why does it rain? Learning objectives

Why do geographers study the weather? The weather has an impact on many of the things that we do! Can you explain how the weather affects these people? Images represent – doctors, drivers, shopkeepers, builders, tour operators and farmers. There are of course many more groups that could have been included… Opportunity to ask pupils to come up with other reasons as to why the weather is important? The ‘weatherwise’ section of the BBC’s website is a good site for further information http://www.bbc.co.uk/weather/

Learning objectives Why do geographers study the weather? What is the difference between 'weather' and 'climate'? Climate graphs Why does it rain? Learning objectives

What is the difference between weather and climate? Climate is the overall average pattern of weather and is usually measured on a larger scale (continents, world) Altitude Latitude Oceans, Lakes, Rivers Precipitation altitude, latitude, water bodies, precipitation, prevailing winds, topography Topography shape, height, depth of land wind direction

The same heat has further to travel near the poles of the earth Heat is more Concentrated at the Equator The same heat has further to travel near the poles of the earth Latitude

Title the Map and color it according to the photo below

Elevation (altitude) Effects on Climate

Title the Map and color it according to the photo below

Temperature and Rainfall effects Climate Climate graphs are a way of showing how temperature and precipitation vary throughout the year for a particular place.

Climate chart for Queen Creek Arizona

Plot your own climate graph Month Jan Fe Ma Apr Jun Jul Aug Sep Oct Nov Dec Rainfall (in) 0.91 Temp (0F) 56.5 Queen Creek, Arizona Use this data to draw a climate graph for Queen Creek. Graph should be titled (x axis, y axis, and main title) Line Graph for Temp (in red) Bar graph for Precipitation (in blue) Number Y axis to 100 degrees F Label the X axis the months of the year J F M A

Plot a Climate Graph for Cape Town Month Jan Fe Ma Apr Jun Jul Aug Sep Oct Nov Dec Rainfall (in) 0.82 0.86 1.25 2.83 4.7 5.7 5.11 4.9 2.76 2.16 1.18 0.98 Temp (0F) 68 69 67 60 55 52 49 45 48 53 58 Cape Town, South Africa Use this data to draw a climate graph for Cape Town. How does it compare to this climate graph of Queen Creek? What makes it’s climate different?

Look at your maps and notes Clearly their day to day weather changes What OTHER factors did you learn about today that effects Cape Town and Queen Creeks Climate?

Learning objectives Why do geographers study the weather? What is the difference between 'weather' and 'climate‘? Climate graphs What is precipitation? Why does it rain? Learning objectives

What is precipitation? Precipitation is water from the atmosphere. It can be in solid or liquid form. Name as many different types of precipitation as you can! An opportunity to make a list of as many types of precipitation as possible: Rain Hail Sleet Snow Fog Dew

Learning objectives Why do geographers study the weather? What is the difference between 'weather' and 'climate‘? Climate graphs What is precipitation? Why does it rain? Learning objectives

Why does it rain? Warm moist air rises. There are three main types of rainfall – relief, convectional and frontal. Why does it rain? Warm moist air rises. As air rises it cools and condenses. Condensed/cooled air forms mini droplet that become to heavy and falls.

Convectional rain

Convectional rain

Relief rain

Relief rain

Frontal rain

Key Ideas Geographers study the weather because it has an impact on people’s daily lives and the activities that they do. Weather is the day to day changes in the atmosphere. Climate is the overall average pattern of weather Precipitation is water from the atmosphere. It can be in solid or liquid form. There are three main types of rainfall – relief, convectional and frontal. In all three situations, rainfall occurs because air is forced to rise.

Weather and Climate Unit Investigative Science The Nature of Storms Weather and Climate Unit Investigative Science

What do You Think?

At any given moment, nearly 2000 thunderstorms are in progress around the world. Most do little more than provide welcome relief on a muggy summer afternoon, or provide a spectacle of lightning. Some, however, grow into atmospheric monsters capable of producing hail the size of baseballs, swirling tornadoes, and surface winds of more than 160 km/hour. These severe thunderstorms can also provide the energy for nature’s most destructive storms—hurricanes! Thunderstorms

How Thunderstorms Form The stability of air is determined by whether or not an air mass can lift. Cooling air masses are stable. Air masses that are warming from the air or land beneath them are not stable. Under the right conditions, convection can cause a cumulus cloud to grow into a cumulonimbus cloud. The conditions that produce a cumulonimbus cloud are the same conditions that produce thunderstorms. How Thunderstorms Form

Three Conditions Needed for a Thunderstorm to Form For a thunderstorm to form, three conditions must exist: 1) a source of moisture 2) lifting of the air mass 3) an unstable atmosphere Three Conditions Needed for a Thunderstorm to Form

For a thunderstorm to form, there must be an abundant source of moisture in the lower levels of the atmosphere. Air masses that form over tropical oceans or large lakes become more humid from water evaporating. This humid air is less dense than the surrounding dry air and is lifted. The water vapor it contains condenses into the droplets that make up clouds. Latent heat, which is released from the water vapor during condensation, warms the air. This causes the air to rise further, cool further and condense more water vapor. Moisture

As moisture condenses into clouds, it releases its latent (stored) heat. This occurs when a warm air mass is lifted into a cooler region of the atmosphere. Dense, cold air along a cold front can push warmer air upward. Warm land areas, heat islands such as cities, and bodies of water can also provide heat for lifting an air mass. Only when water vapor condenses can it release latent heat and keep the cloud rising. Lifting

If the surrounding air remains cooler than the rising air mass, the unstable conditions can produce clouds that grow upward. This releases more latent heat and allows continued lifting. When the density of the rising air mass and the surrounding air are nearly the same, the cloud stops growing. Cumulus clouds can become cumulonimbus clouds as the air mass rises, cools, releases more heat, rises, cools again—over and over. Unstable Atmosphere

Air Mass Thunderstorms Air near surface is warmed during the day. Warm air rises and condenses to form cumulous clouds in the afternoon. Scattered, isolated. Most moisture evaporates but eventually it accumulates into taller clouds. Air Mass Thunderstorms

Forms along a Cold Front

Or…along a Warm Front Unstable air mass

Orographic lifting over mountains

Forms when air converges, is forced up, cools adiabatically, form clouds These tend to be brief, short-lived storms with moderately heavy downpours.

3 Stages of Development of a Thunderstorm Pg. 288

Stage 1 Cloud continues to grow as long as there is a supply of warm, moist air. Updraft occurs. http://www.youtube.com/watch?v=DualOU_gBn0

Bergeron Process Ice crystals collect water molecules and grow larger while cloud droplets evaporate and get smaller. 42

Stage 2 Mature stage

Stage 3

Developing Cumulonimbus Fair-Weather Cumulus

Well-Developed Cumulonimbus

Severe Thunderstorm Development along a Cold Front

Roll Cloud http://www.youtube.com/watch?v=QHHUfb7olQ0

Average Number of Thunderstorm Days

Atmospheric Hazard Flash Floods - Number One Thunderstorm Killer

Supercell Thunderstorm A single, very large (65,000 ft. high) massive cloud 12-30- miles in diameter, Lasts for many hours

Cluster of Supercell Thunderstorms

Temperature Inversion enhances formation of severe thunderstorms: dense, cold layer above prevents warm, moist air from rising. Surface air heats up, and finally erupts upward, producing an unusually large cumulus cloud 53

Mammatus Sky

Microburst http://www.youtube.com/watch?v=fjFTH3s6BlM Strong DOWNDRAFTS Beneath the thunderstorm Small 2.5 miles across Cold dense, sinking air Last 2-5 minutes Also called wind shears http://www.youtube.com/watch?v=fjFTH3s6BlM