Teaching Soaring Weather

1. Teaching Soaring Weather Soaring Safety Foundation FIRC Rich Carlson

2. Basic Principles • Obtain the basic weather data • Know how the atmosphere works • Use some simple calculations to see if soaring is possible • Graphs and pictures improve student understanding • Weather analysis continues throughout the flight

3. Obtaining Weather Data • Look Outside • Local sounding • Flight Service Station (1-800-WXBrief) • National Weather Service • Duat • 3rd party service provider • Internet (email and Web)

4. Atmospheric Assumptions • Pressure lapse rate 1” hg/1000 ft • Dry adiabatic lapse rate 5.4o (3c)/1000 ft • Wet adiabatic lapse rate less than dry • Dew point decreases 1o / 1000 ft

5. Soaring Calculations • Thermal Index (TI) • measured - adiabatic (minus is better) • Cloud base • (max surface - dewpoint)/4 (in 1000’s of ft)

6. Obtaining a Weather Briefing • FSS call 1-800-992-7433 (WXBrief) • Identify yourself as a glider pilot • Give Aircraft ‘N’ number • Say type of flight and location • Ask for standard briefing • Ask for surface reports • Ask for winds aloft forecast • Ask for Soaring forecast • Ask for other pertinent data (Notams, TFR’s)

7. Pseudo-Adiabatic plot Src: Soaring Flight Manual

8. Typical FSS Soaring Forecast • T.I. at 5000 ft -5 • T.I. at 10,000 ft +2 • Height of -3 7200 • Top of Lift 8500 • Max Expected Temp 89 • Morning Low* 50

9. Step 1, draw the adiabatic line

10. Step 2, add the T.I. dots

11. Step 3 Draw the sounding

12. Internet Sources • Kevin Ford - http://www.soarforecast.com • NOAA-FSL, Forecast Systems Laboratory - http://www-frd.fsl.noaa.gov/mab/soundings/java/ • Aviation Digital Data Service - http://adds.aviationweather.noaa.gov • Dr Jack BLIPMAP - http://www.drjack.info/BLIP/index.html

13. Kevin Ford Plots • === Interpolations (temps in deg. F, altitudes in feet MSL) === • MSL *TI* Wdir@kts trig VirT 1.2 degrees/division ("`": Dry Adiabatic) • ----- ---- -------- ---- . ---- ----------------------------------------- • 10000 12.4 40 | -9.8 ` : • 9500 11.6 39 | -8.6 ` : • 9000 10.7 280 27 37 | -7.5 ` : • 8500 9.8 35 | -6.5 ` : • 8000 8.8 290 25 34 | -5.5 ` : • 7500 7.9 32 | -4.5 ` : • 7000 6.9 295 24 30 | -3.5 ` : • 6500 6.0 29 | -2.6 ` : • 6000 3.7 300 27 25 | -4.0 ` : • 5500 3.6 24 | -1.5 ` : • 5000 3.5 24 | 0.9 ` : • 4500 3.3 24 | 3.3 ` : • 4000 2.1 22 | 3.7 ` : • 3500 0.8 19 | 4.1 `: • 3000 -0.5 18 | 4.4 :` • 2500 -1.8 16 | 4.8 : ` • 2000 -2.1 15 | 7.0 : ` • 1500 -2.1 15 | 9.7 : ` • 1000 -2.1 15 | 12.3 : `

14. NOAA Forecast Plot

15. ADDS METAR/TAF Data

16. Dr Jack BLIPMAP

17. Local factors • Terrain features • Ridges • Mountains • Rivers • Lakes • Towns

18. Local factors • Ridge conditions • Calculations • Predictions • 90O +/- 30O to ridge line • 10 - 15 kts • Ridges • Lift extends 2 – 3 times the ridge height • Ridge length should be several miles

19. Ridge Lift Zones

20. Local factors • Wave conditions • Calculations • Predictions • Wind at peak • 15 – 20 kts • Wind 2000 m above peak • Same direction • 20 – 25 kts higher

21. Mountain Wave System

22. Transition pilot wave sketch

23. Some rotor research in progress

24. Some rotor research in progress

28. Thermal Predictors/Indicators • Negative Thermal Index values at alt. • Forecast plots • Clouds • Birds/Gliders circling • Dirt, crops, houses, animals rising before your eyes

29. Go/No-Go Decision Making • Use realistic scenarios • Storms forecast for later in the day/evening • Effect of strong x-wind • Local vs X-C flight • Pilot experience level

30. Continuing Weather Analysis • Obtaining enroute weather data • Flight Watch (122.0 Mhz) • Airport automated weather services • Obtaining end-of-flight weather data • Wind direction for landing • Current Altimeter setting

31. En Route Flight Advisory Service (Flight Watch) • AIM section 7-1-5 • Real-time weather advisories • National coverage above 5000 ft on 122.0 • Available 6:00 am to 10:00 pm • State ARTCC facility, N number, & nearest VOR name

32. Types of Fronts • Cold • Good soaring conditions • squall lines 50 - 300 miles ahead • Warm • temperature inversion • broad cloud system precedes front • Occluded • both warm & cold cloud patterns

33. Cold Front Src: Aviation Weather AC 00-6A

34. Warm Front Src: Aviation Weather AC 00-6A

35. Cold-Occlusion Front Src: Aviation Weather AC 00-6A

36. Warm-Occlusion Front Src: Aviation Weather AC 00-6A

37. Seasonal Weather Operations • Density Altitude • Thunderstorms • Frost, Snow Ice • Temperature extremes • Wind shear • Microbursts

38. Determining When to Land • What effect does the wind have on landing?

40. 27 9 Effect of 20 Kt wind Time on Downwind: More, Less, no Change? Altitude loss: More, Less, no Change? 20 Kts

41. 27 9 Effect of 20 Kt wind Time on base: More, Less, no Change? Altitude loss: More, Less, no Change? 20 Kts

42. 27 9 Effect of 20 Kt wind Time on Final: More, Less, no Change? Altitude loss: More, Less, no Change? 20 Kts

43. 27 9 Effect of 20 Kt wind Which path is your student likely to fly? Which path do you want them to fly? 4 20 Kts 3 1 2

44. Final Approach(No wind) 60 kts @ 500 ft/m decent rate 12:1 glide slope 24 seconds 200 2400

45. Final Approach(20 Kt Head Wind) 60 kts @ 500 ft/m decent rate 8:1 glide slope 24 seconds 200 2400 1600

46. Final Approach(20 kt wind shear) 60 kts @ 500 ft/m decent rate Maintain constant speed during approach How much time remains? 200 20 kts 0 kts X Y 2400 1600

47. Decision Time • With a 20 kt shear, are you likely to • overshoot (into area Y) • undershoot (into area X) • Said another way, what actions do you need to take to reach your intended touchdown point • close the spoilers to extend (undershooting) • open the spoilers to sink faster (overshooting) • Another variation, what will the aim spot do? • move up on the canopy (undershooting) • move down on the canopy (overshooting)

48. Glide Distance

50. How much Altitude does it take to regain original airspeed? ?