Does Weather Follow a Pattern?

1. Does Weather Follow a Pattern? Chapter 6

2. Weather and Climate • Weather refers to the day to day conditions of the atmosphere in a specific area • Climate describes the weather conditions that occur in a specific area over a long period of time. • Meteorologist is a weather specialist • Humidity refers to the amount of moisture in the air and is measured as a percentage • Precipitation is all the moisture that falls from the sky

3. Weather and Its Influences • Weather affects our lives daily • Sometimes the conditions can be extreme and cause natural disasters • Impact of weather is not always dramatic • Plants and animals are also influenced by the conditions of the atmosphere

4. Health Indicators • Humidexused to measure the combined effect of temperature and humidity • Wind Chill factor measures the chilling effect on human skin of the wind combined with cold temperatures • Ultraviolet (UV) rays can damage the eyes and burn deeply into unprotected skin

5. Humidex

6. Wind Chill

7. Weather Patterns across Canada • Geographers search for patterns so that they can predict changes to the Earth’s surface • Identifying weather patterns make it easier to predict tomorrow’s weather • Weather patterns follow a general pattern

8. Weather Patterns across Canada (cont.) • In Canada, places near Atlantic and Pacific Ocean • are wetter • Prince Rupert, BC is the wettest, receives precipitation for over 300 days a year • Winter weather is milder • West Coast temperatures rarely drop below freezing

9. Weather Patterns across Canada (cont.) • Interior of Canada and far North • Enjoy more hours of sunshine • Receive less precipitation • Real extreme in temperatures • Hot summers and cold winters

10. How Air Masses Affect the Weather • Air masses are large bodies of air with particular temperature and moisture characteristics • Warm front is when warm, moist air from the Gulf of Mexico moves north • Cold front is when cold, dry air from the Arctic moves southward

11. How Air Masses Affect the Weather (cont.) • Communities near the Great Lakes have changeable weather • Different types of air masses push into regions from different directions • Warm front rides up over cooler air in front of it causing clouds to form and is often followed by precipitation • Cold front pushes warm moist air upward and causes dark clouds to form and is often followed by powerful thunder and lightening storm.

12. Canada’s “Storm of the Century” • Early 1998 • Eastern Ontario and Southern Quebec • 5 continuous days of freezing rain • Large warm air mass from Gulf of Mexico swept northeastward by a high speed wind (jet stream) • In southern Canada, it met a cold air mass and rode up over it • Clouds and rain developed, and the water droplets froze wherever they landed

13. Canada’s “Storm of the Century” • Weight of ice caused trees and hydro towers to break • Over 2 million people left without power in the middle of winter • 25 deaths • At least half a billion dollars damage • Widespread environmental destruction

14. How the Oceans affect the Weather • El Nino • Spanish for “boy child” • Warm Pacific Ocean current that reaches the coast of Peru during December • Sometimes the water is warmer than usual and causes great changes in weather over North and South America • Warm ocean water evaporates more quickly and results in more clouds and precipitation • During El Nino winters Canada has milder conditions and rain often replaces snow

15. How the Oceans affect the Weather (cont.) • La Nina • Spanish for “girl child” • Large pool of cold water appears off the Pacific coast of South America • Results in colder and snowier weather in Western Canada