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# Tonight

Sept 7 Weather Review Weather map basics Energy that Drives the Storms (chapter 2) More Weather Maps ( Isopleths ) Classwork (HW#3) Homework #4. Tonight. Hrcn Earl Visible. Weather Review. Hrcn Earl Infrared (IR). Weather Review. Hrcn Earl Enhanced IR. Weather Review.

## Tonight

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### Presentation Transcript

1. Sept 7 • Weather Review • Weather map basics • Energy that Drives the Storms (chapter 2) • More Weather Maps (Isopleths) • Classwork (HW#3) • Homework #4 Tonight

2. Hrcn EarlVisible Weather Review

3. Hrcn Earl Infrared (IR) Weather Review

4. Hrcn Earl Enhanced IR Weather Review

5. Hrcn Earl Visible Weather Review

6. “Hurricane Force Wind Gusts” • Criteria: 1-minute sustained winds ≥ 74 mph • Peak 3 to 5-second gusts ~ 30% higher • Exerted Force: proportional to the square of the wind speed • Force from a 74 mph gust = 14.0 psf • Force from a 96 mph gust = 23.6 psf • 69% higher. Weather Review

7. TS HermineVisible Weather Review

8. TS HermineInfrared Weather Review

9. TS HermineEnhance Infrared Weather Review

11. TS HermineQPF Weather Review

12. Weather Symbols and Maps

13. Station model 80 021 -23 63

14. Weather Symbols

15. Sky Symbols

16. Wind Symbols

17. Pressure Tendency

18. Station model 80 021 -23 63

19. Station model 80 021 -23 63 Temperature Surface: ºF Upper air: ºC

20. Station model 80 021 -23 63 Dew point temperature Surface: ºF Upper air: ºC

21. Station model 80 021 -23 63 Totalsky cover ** Depicted by shading in circle

22. Station model 80 021 -23 63 Current weather conditions ** If blank, “no weather”

23. Station model 80 021 -23 63 Wind direction – of wind toward center

24. Station model 80 021 -23 63 Wind speed Long barb = 10 knots Short barb = 5 knots Flag = 50 knots ** Notice range of wind speeds (i.e., 28-32 knots)

25. Station model 80 021 -23 63 Sea level pressure **If first number is 5 or greater, then place 9 in front --Otherwise, place 10 in front **Place decimal point between last two numbers

26. Station model 80 021 -23 63 Change in surface pressure during last 3 hours ** In tenths of mb ** Line describes how pressure changes over time from left to right

27. Example 1 • Temperature: 76 ºF • Dew point: 65 ºF • Sky cover: Completely overcast • Current weather: Light rain • Wind direction and speed: Southwest at 15 knots • Sea level pressure: 995.3 mb • Pressure tendency: Increase of 1.6 mb; rising steadily 76 953 +16 65

28. Example 2 • Temperature: 10ºF • Dew point: 8ºF • Sky cover: 7/10 or 8/10 • Current weather: Snow shower • Wind direction and speed: North at 3-7 knots • Sea level pressure: 1010.5 mb • Pressure tendency: Decrease of 0.4 mb; falling, then steady 10 105 -4 8

29. High & Low Pressure Systems • Air pressure Patterns are main organizing feature • Circulation in Northern Hemisphere • Clockwise around Highs (H) • CCW around Lows (L) • Clouds & Precip around Lows • Temperature patterns result from latitude, wind flow and cloud cover

30. Plotting Fronts • Boundary between Different Air Masses • Types of Fronts

31. Weather Maps

32. Weather Maps

33. Weather Maps

34. Weather Maps

35. Weather Maps

36. Weather Maps

37. Weather Maps

38. CHAPTER 2 ENERGY THAT DRIVES THE STORMS

39. ENERGY AND HEAT TRANSFER • Energy is the capacity to do work on some form of matter • Potential energy: The total amount of energy stored in any object is capable of doing • Kinetic energy: Any moving substance possesses energy of motion

40. Cold Air vs. Warm Air Slower and closer together ….. Faster and farther apart Fig. 2.1, p. 37

41. ENERGY AND HEAT TRANSFER • Atoms and molecules have kinetic energy due to their motion (heat energy) • Most important energy in terms of weather and climate is radiant energy from the sun • Air temperature is a measure of the average kinetic energy of its molecules

42. ENERGY AND HEAT TRANSFER • Heat is energy being transferred from one object to another because of a temperature difference • After heat is transferred, it is stored as internal energy • Heat is transferred in the atmosphere by • Conduction • Convection • Radiation

43. ENERGY AND HEAT TRANSFER • Latent heat: energy required to change a substance, such as water, from one state to another • Evaporation is a cooling process due to absorption of latent heat from the environment • Condensation is a warming process due to a release of latent heat to the environment

44. Changes of State Fig. 2.2, p. 37

45. ENERGY AND HEAT TRANSFER • Conduction: the transfer of heat from molecule to molecule • Always flows from warmer to colder • Air is an extremely poor conductor of heat

46. ENERGY AND HEAT TRANSFER • Convection: transfer of heat by the mass movement of a fluid (water or air) • Example: Pan of boiling water • Convection circulation: warm air expands and rises then cools and sinks • Thermal cell, convection, thermals

47. Thermal Circulations Fig. 2.5, p. 40

48. Thermal Circulations Fig. 2.6, p. 40

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