2. Refers to the state of the atmosphere at a specific time and place. Refers to the state of the atmosphere at a specific time and place. The one thing that you can talk to anybody about The one thing that you can talk to anybody about If you don’t like the weather just wait around it will change in Ohio If you don’t like the weather just wait around it will change in Ohio What are some of the factors that affect the weather? What are some of the factors that affect the weather?

3. Temperature is the measure of the average amount of motion in particles. Faster moving particles = warmer temps Slower moving particles = colder temps

4. a natural movement of air of any velocity a natural movement of air of any velocity Air moving from an area of high pressure to an area of low pressure

5. Humidity The amount of water vapor present in the air

6. Relative Humidity Tells us how “full” the air is at the time of measurement.Tells us how “full” the air is at the time of measurement. A ratio of the amount of water vapor in the air to the maximum amount of water vapor the air can hold (at a set temperature)A ratio of the amount of water vapor in the air to the maximum amount of water vapor the air can hold (at a set temperature) What can hold more water, warm or cool air? WHY?What can hold more water, warm or cool air? WHY? For example, 90% relative humidity means that at that moment the air is holding 90% of the maximum amount of water it could.For example, 90% relative humidity means that at that moment the air is holding 90% of the maximum amount of water it could.

7. Practice!  Assume that 1 m 3 of air at 25ºC contains 11g of water vapor. At this temperature the air can hold 24 g/m 3 of water vapor. Calculate the relative humidity.  11 g/m3 x100 = 46% 24 g/m3 24 g/m3

8. Psychrometers  Instrument used to measure relative humidity  2 thermometers (one wet bulb, one dry bulb)  Difference in bulb temperature readings indicates relative humidity  The larger the temp. difference, the lower the humidity

9.  Masses of small water droplets or tiny ice crystals that float in the air.  Three main types are cirrus, cumulus, and stratus.  Other clouds are a mixture of these three main types.

11. Cirrus  Cirro- means “curled” or “feathery”  Form highest in the sky; are made up of ice crystals; and appear as curls, tufts, or wisps.  Usually signal the end of clear weather.

12. Alto  A prefix meaning “middle range of clouds “ and used to describe clouds that lie from 6,500-18,500 ft. (1,980-5,640m).

13. Stratus  Strato- means “layer-like” or “sheet-like.”  Low-lying, dull-colored clouds that form in layers or sheets.  Usually bring drizzling rain or light-falling snow.

14.  Cumulo- means “heaped” or “piled”  Cottony clouds with flat, usually gray bases, and puffy, bright tops.  Usually signal good weather, but if atmosphere is unstable, can build into towering clouds that produce showers and thunderstorms.

15. Nimbus  A rain cloud

17. Other Cloud Types CirrocumulusCirrostratus StratocumulusCumulonimbus

18. More Cloud Types Altocumulus Altostratus Nimbostratus

19. Precipitation  Water that falls from the clouds  Air temperature determines the form of precipitation that falls  4 main types of Precipitation: Rain, Sleet, Snow and Hail

20. Types ofPrecipitation Types of Precipitation Rain Sleet Snow Hail

21. High and Low Pressure Areas High pressure causes air to sink Usually results in several days of clear sunny skies Air rises in low pressure areas and forms water droplets Usually results in rain and storms

22. Air Masses  A large body of air that has properties similar to the part of the Earth’s surface over which it develops.

24. Air Mass Map

25. Fronts  A boundary between two air masses of different density, moisture, or temperature.

26. Cold Front

27. Warm Front

28. Occluded Front

29. 4. Occluded Front: Formed when a cold front overtakes a warm front This occurrence usually results in storms over an area In U.S., the colder air usually lies to the west

30. Stationary Front

31. Severe Weather Thunderstorms Lightning Tornadoes

32. More Severe Weather HurricanesBlizzards

33. Severe Weather Safety WWWWatches- conditions are favorable WWWWarnings- conditions already exist EEEExamples- Tornadoes, Flooding, Thunderstorms, Blizzards, Winter Mixes and Hurricanes

35. Lightning

37. Tornado Alley

38. Fujiti Scale

40. Weather Map

41. Hurricane

42. Hurricane Scale

43. Hurricane Charley

44.  Two sources of forecasting weather –Data collected from upper atmosphere –Data collected on the Earth’s surface

45. Weather Station Model

46. Isobars  Isobars-connect points of the “same”  Examples: temperature and wind speed  The further away the lines the lower the wind speed