Aviation Weather

1. Aviation Weather

2. Warm-Up Questions CPS Questions 1-2 Chapter 2, Lesson 3

3. Lesson Overview • Causes of atmospheric instability • Types and causes of turbulence • How types of severe weather affect aviation Chapter 2, Lesson 3

4. Quick Write Colonel Duckworth was an expert in instrument flying. Why was this skill important when flying through a hurricane? (Note to teacher: Use “Pick a Student” button in CPS) Chapter 2, Lesson 3 Courtesy of the National Museum of the USAF

5. Causes of Atmospheric Instability • Small vertical movements grow until they produce turbulent airflow and air circulation • Adiabatic process takes place in upward and downward moving air • When air rises, pressure decreases, volume increases, and temperaturedecreases • When air descends the opposite is true Chapter 2, Lesson 3 Reproduced from NOAA/National Weather Service

6. Causes of Atmospheric Instability, cont. • Water vapor is less dense than air • Moisture decreases air density, causes air to rise • Decrease in moisture makes air denser and causes it to sink • Moist air cools at a slower rate than dry air • Combination of moisture and temperature determines air stability and weather Chapter 2, Lesson 3

7. Activity 1: Air Lapse Rates • Convert Celsius temperatures to Fahrenheit temperatures • Review the examples and then complete the temperature conversion problems Chapter 2, Lesson 3

8. Learning Check Questions CPS Questions 3-4 Chapter 2, Lesson 3

9. Thermal Turbulence • Rise of warm air, taking place on a local scale • Plowed ground, rocks, sand, and barren land emit a large amount of heat • Water, trees, and other growing things absorb heat • These reactions to sun’s energy results in uneven heating of the air, creates small areas called convective currents Chapter 2, Lesson 3 Reproduced from NOAA/Earth System Research Laboratory

10. Convective Currents • Create bumpy, turbulent air • On low-altitude flight, pilots may run into updrafts over pavement or barren places, and downdrafts over water or forests • To avoid these turbulent conditions, they can fly at higher altitude, even above cumulus clouds Chapter 2, Lesson 3 Reproduced from US Department of Transportation/Federal Aviation Administration

11. Mechanical Turbulence • Generated by resistance of one object moving over another • As air moves over Earth’s surface, friction that develops between air and surface modifies the air’s movement • Large objects—mountains to man-made structures such as buildings—generate mechanical turbulence Chapter 2, Lesson 3 Reproduced from US Department of Transportation/Federal Aviation Administration

12. Wind Shear • Abrupt, dramatic change in wind speed, direction, or both • Low-level are linked with thunderstorms, and temperature inversions, with strong upper-level winds • High-Level begins around 18,000 feet and can produce clear air turbulence Chapter 2, Lesson 3 Reproduced from NASA

13. Activity 2: Types of Turbulence • Describe the type of turbulence presented and explain its impact on flight using the illustrations provided Chapter 2, Lesson 3

14. Learning Check Questions CPS Questions 5-6 Chapter 2, Lesson 3

15. How Types of Severe Weather Affect Aviation—Thunderstorms • Convection triggers thunderstorms • Water vapors rising with warm air condense into clouds • Convection process then continues within the clouds • At the tropopause the unstable atmosphere stabilizes Chapter 2, Lesson 3 Reproduced from NOAA/Earth System Research Laboratory

16. Thunderstorms—Air Mass and Steady-State • Air mass occur in unstable air, last only an hour or two • Warm surface temperatures cause this type of storm • Steady-state often form into narrow band of active thunderstorms called squall lines • Updrafts grow stronger and last much longer than in an air mass storm Chapter 2, Lesson 3 Reproduced from US Department of Transportation/Federal Aviation Administration

17. Hazardous Flying Conditions • Look for squall lines, tornadoes, turbulence, icing, hail, lightning, and poor visibility • Light aircraft won’t be able to fly over thunderstorms • Air Force instructs pilots to fly 20 miles from the storm’s edge Chapter 2, Lesson 3 Courtesy of NOAA Photo Library; OAR/ERL/NSSL

18. Squall Lines • Develop in moist, unstable air, on or in advance of a cold front • Often contain steady-state thunderstorms • Form quickly, are strongest in the late afternoon and early evening Chapter 2, Lesson 3 Courtesy of NOAA/National Weather Service

19. Tornadoes • Materialize out of the most violent thunderstorms • Can sharpen into a powerful vortex that reaches from the ground into the clouds • Funnel-shaped cloud that stretches earthward from a cumulonimbus base Chapter 2, Lesson 3 Courtesy of NOAA/National Weather Service

20. Turbulence • Inside a cloud, pilots encounter the strongest turbulence • Outside of clouds, as much as several thousand feet above and 20 miles sideways • Gust front may stir up trouble as far as 15 miles ahead of any storm Chapter 2, Lesson 3 Courtesy of NOAA/National Weather Service.

21. Icing—Hail • Icing, is a product of updrafts • In a thunderstorm, the updraft lifts water vapor above freezing level,, the water supercools • Hail, another form of supercooledwater • Can be just as dangerous to aircraft as turbulence Chapter 2, Lesson 3 Reproduced from US Department of Transportation/Federal Aviation Administration.

22. Lightning—Poor Visibility • Lightning—hazard that’s most closely associated with thunderstorms • Can puncture an aircraft’s skin, damage its communications and navigational equipment • Poor Visibility— generally visibility is near zero within a thunderstorm cloud Chapter 2, Lesson 3 Courtesy of NOAA.

23. Activity 3: AtmosModelerLab—Temperature and Altitude • Use the AtmosModeler interactive simulation software to investigate how changes in altitude affect temperature • Gather and record data on temperature and altitude then use that information to make calculations Chapter 2, Lesson 3

24. Learning Check Questions CPS Questions 7-8 Chapter 2, Lesson 3

25. Activity 4: Severe Weather Investigation • Create a presentation on one of the severe weather events • Conduct and investigate research using the sources identified Chapter 2, Lesson 3

26. Summary • Causes of atmospheric instability • Types and causes of turbulence • How types of severe weather affect aviation Chapter 2, Lesson 3

27. Review Questions CPS Questions 9-10 Chapter 2, Lesson 3

28. Next…. • Done – aviation weather • Next – weather forecasting Chapter 2, Lesson 3 Courtesy of NASA/George Shelton