1. Soaring Weather Presented by Jim Martin 2015

2. Basic Principles Obtain the basic weather data 1st Is it Dangerous / Soarable ? Understand How the atmosphere works –Its Our Engine! –Calculations to see if soaring is possible Graphs and Maps improve understanding Continue throughout the flight to Analyze & Update

3. Obtaining Weather Data Look Outside – Gain Personal Experience –…Yet Airport may be 60 miles away! Consult Online Weather Sources – 1st –1800WxBrief.com (Lockheed Martin off. Site) –National Weather Service / Duat / DUATS –Call Flight Service Station (1-800-WXBrief) ASOS /AWOS /ATIS – Phone #s in AFD Make a Local Sounding Cell Phone / NEXRAD Sites

4. Weather Briefing Online Http\\www.1800WxBrief.comHttp\\www.1800WxBrief.com FSS call 1-800-992-7433(1800WXBrief) –Identify yourself as a glider pilot Give Aircraft ‘N’ number type of flight and location –Ask for; standard briefing / forecast surface reports winds aloft forecast Soaring forecast – including LI, overcast, turbulence other pertinent data (Notams, TFR’s)

5. Same Charts as Briefer Uses

6. ADDS METAR/TAF Data

7. VansAirForceWeather Better Site - Yet Not Official All Charts come from Official Sites Logically Grouped Together Typical Order Pilot’s are interested in Can be Customized to your location or likes

8. VansAirForceWeather.com

11. Decision Making Be realistic! –Are Storms forecast for later in the day/evening –Strong x-winds later in day? (not often forecast) –Local vs Long X-C flight –Your experience level –Precipitation? –How Soarable is the Weather?

12. Continue Your Weather Analysis throughout Flight Enroute weather data –Flight Watch (122.0 MHz) –Airport automated weather services – ATIS/ASOS/AWOS Smart Phone / Cell Phone Updates End-of-flight weather data –Wind direction for landing – ATIS / ASOS –Current Altimeter setting Other Pilots 122.8 / 122.9 / CTAF 123.5MHz glider ground crew

13. En Route Flight Advisory Service (Flight Watch) 122.0 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 Eg. “Buffalo Flight Watch, this is..”

14. Hazardous Weather Fronts Winds Airmass Changes Precipitation Overcast

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

16. Cold Frontal Weather Cold Front Passage - Cumulus then Cumulonimbus Overcast / High Cirrus 2 Days Prior May Superheat air in front of airmass if fast moving Squall lines 50 - 300 miles ahead – Gusty day prior Frontal Passage = Wind Shift +Day after is typically Super Adiabatic (Chopped Up) +Ground has to Dry Out +Good Soaring conditions - 2 days after +Typically Clear, Good Visibility, Higher Cloudbase

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

18. Warm Frontal Weather Warm Airmass – High Stratus Increasingly Lowers –Deep temperature inversion – Increasingly Stable –lowering cloudbases –broad overcast cloud system precedes front –+ Stable Air = Ridge Soaring Occluded = Generally Not Soarable –both warm & cold cloud patterns

19. Src: Aviation Weather AC 00-6A Colder Overtaking Occlusion Front Warm Air Aloft

20. Src: Aviation Weather AC 00-6A Warm-Occlusion Front Cool Air overtaking Colder

21. Airmass Changes Mount a Sensitive Thermometer (measures.10 deg change) Able to detect airmass changes Watch for significant Cloud changes throughout the day Can signal approaching Front / Airmass change Winds: Shifting or Speed Significant changes

23. Atmospheric Facts WEIGHT: A cubic inch of air near the ground at sea level has about 14.7 pounds of air sitting on top of it, pushing it down Pressure Decreases with Altitude 1” hg (Mercury) = 1000 ft difference 14.7” @ Sea Level (Density) @ 18,000 ft Density / Pressure is ½ of sea level

24. Air Facts Air holds Water: Water Vapor REDUCES Density of Air –10C Warmer Air can Absorb TWICE amount of Water Vapor….. –10C Colder Air can only hold ½ the water

25. Water Vapor Content Air always holds water, but only up to a certain amount of it--more than that and you get condensation The higher the dew point temperature, the more water is in the air When Dewpoint and Temperature are equal = 100% Saturated = Clouds /Fog

26. Bouyancy Warm Air Rises through Cooler Air Aloft –Bigger the Difference = Faster Ascent Rate ! –Larger Heated Area = More Inertia & Momentum (Rises Higher) It takes a lot of sunshine to evaporate any water on the ground Moist Air (Saturated) Rises ½ as Fast as Dry

27. Lifting Rate Assumptions Any ground water has to evaporate 1 st –440 calories / gram of water / 1 deg C –A lot of heat to evaporate a small amount of H 2 0 Air rises at the DRY Lapse rate 1 st from the ground ~3-5C/1000ft (It’s not Saturated) As it cools, the parcel humidity increases until it reaches the condensation level (cloudbase) where it’s 100% saturated –Rises at the WET Lapse Rate ~2C/1000ft

28. What are SOUNDINGS? Temperature and Dewpoint and Wind Directions and Speed plotted vs. increasing Altitude (Pressure) –Done at 6AM and 6 PM with weather balloons –Now done by Satellites with Computer modelling Plot is called a “Sounding” and Chart is called a “Skew-T” It displays the characteristics of the airmass

29. Skew-T / Sounding Constant Temperature “Skewed”.. Angled Up & to the Right Vs. Altitude

30. Constant Temp NOAA Chart Colors

31. Mixing Ratio = Constant Water Content (Gray) Temp (Red) Alt. (Blue) Pressure / Feet All those Lines !! Actually calculations

32. Dry Adiabat Line from Surface Temp at Surface (1200 ft MSL) = 25C Rises along DRY Adiabatic Line to 7500 ft where it has cooled to 08C

33. Cloudbase Project Up from Surface Dewpoint Temp (10C) Along Constant Mixing Line to where it intersects the Dry Adiabat drawn from the Surface Temp (of 25C) = 7000 ft.

34. Lapse Rates Rate at which the Temp Decreases as the Air Ascends DRY Adiabatic = 3-5C (5-7F) / 1000ft WET Adiabatic = 2C (3.5F)/ 1000ft So… Dry air is Better! Rough Estimation … Cloud base = (max surface temp - dewpoint)/2C = (in 1000’s of ft)

37. Thermal Lifting If Air Above is cooler and not saturated… –Rises and cools at the DRY LAPSE Rate (5F / 1000ft) –Once it cools to the Dewpoint … it rises at the WET (Saturated) LAPSE Rate (3.5F / 1000ft) ==== Slower

38. Airmass Stability Stable = Doesn’t Want to Go Up ?! Unstable = Wants to Go Up! Thermal Index (TI) / Lifted Index (LI) = How Fast it wants to Go Up!

39. Cloudbase Estimate Dry adiabatic lapse rate5.4 o (3C)/1000 ft –Wet adiabatic lapse rateless than dry –Dew point decreases2C o / 1000 ft Therefore if air is unsaturated…. –Surface Temp – Dewpoint Temp ÷ 2C = Cloudbase eg. 20C (surf.)–10C (dewpoint) = 10 ÷2 = 5000 ft Cloudbase

40. Conclusions Drier & Cooler Air aloft means Stronger Thermals Drier ground means thermals start earlier As Surface Dewpoint Spread increases…. Cloudbase goes UP Higher elevations (at same temp) trigger thermals earlier and stay later

41. Airmass Stability Stable = Temp increases (Inversion)/Stays the same, or same as std lapse rate as altitude increases {pos stabilty number} Unstable = Temp decreases more rapidly than standard lapse rate {minus number) Thermal Index (TI) / Lifted Index (LI) is comparison between 5000ft (850mb) temp and 10000 ft (700mb) temp

42. Typical FSS Soaring Forecast (6AM Sounding) Morning Low*50F10C Max Expected Temp89F35C T.I. at 5000 ft-5 T.I. at 10,000 ft+2 Height of -3 TI7200’ Top of Lift8500’ (They assume a 3C lapse Rate / 1000ft) Note: Their Skew-T Looks Different !

43. Step 1, draw the adiabatic line 35C

44. Step 2, add the Sounding

45. Step 3 Draw the sounding

46. Src: Soaring Flight Manual Step 4: Calculate the Difference between the Dry Lapse Rate Line and the Sounding at the Altitude you Select = Thermal Index

47. Src: Soaring Flight Manual Thermal Index TI = +6 TI = -10

48. Dewpoint Plots Wherever the Dewpoint Touches or is close to the plotted temperature = Clouds will form If the Dewpoint is close at other levels… cloud layers will exist at that level

49. 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

50. 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 : `

51. NOAA Forecast Plot

52. Cloud Layer 1000 to 7500 ft Cloud Layer 30,000 ft

53. Noaa Skew T’s Temperature Plot vs Altitude –If Temp increasing = Stable Air (Inversion) Dewpoint Plot vs Altitude –If Temp Plot touches or is close to Dewpoint = –Predicts where Clouds and Layers will form Winds Aloft Knowing Forecast Max Temperature = –Predicts Height of Thermals –If Significant Heating = Excess Energy is Hatched

54. Evaporation Evaporation take 7.5 times as much energy as melting or freezing. ( 440 cal. / deg C) Condensation at Cloudbase Gives Off that Energy and the parcel continues to rise unless an inversion is above it. Avoid Rain Soaked Areas It May take a day or more to dry the ground after rainfall

55. Definitions LCL (Lifted Condensation Level) –Cloudbase = altitude where air is 100% saturated CCL (Convective Condensation Level) –Height predicted a parcel will reach based upon max temp {above the LCL} LI (Lifted Index) negative indicates unstable = Thermals KI (K Index / Showalter) amount of water in parcel if >400 TStms likely

56. Best Sites Interactive Skew T (Moninger/ NOAA) http://www-frd.fsl.noaa.gov/mab/soundings/java/

57. Bad Winter Day Massive Inversion………

58. If it Got to 75F.. Could Soar to 30,000 ft.. Yet Clouds from Surf to….. 15,000 ft !!

59. Best Book Understanding the Sky By Dennis Pagen

61. Clouds & Thermals

65. Condensation releases latent heat. This causes the temperature of a cloud to be warmer than it otherwise would have been if it did not release latent heat. Anytime a cloud is warmer than the surrounding environmental air, it will continue to rise and develop. The more moisture a cloud contains, the more potential it has to release latent heat.

66. Dr Jack’s BLIPMAPS

67. BLIPMAP Assumptions Your Sailplane Sinkrate must be subtracted from the predicted Climbrate Must Subtract the Terrain Height from the Thermal / Cloudbase Height (is MSL Alt.) Assumes NO Overcast unless Stippling added Is Based on Atmospheric Models forecast for 6 AM –is NOT Updated throughout day

68. Blipmaps Does Not predict or use any Precipitation on the ground

69. Local Effects Terrain features –Ridges –Mountains –Rivers –Lakes –Towns

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

71. Ridge Weather Stable Lower Level Airmass Wind within 30 deg of perpendicular to Ridge Wind increasing with altitude Wind > 5K, better the faster, upto 30K Beware of Sink behind ANY ridge

72. Ridge Lift Zones Gradual SlopeSharp Slope Eddy formation

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

74. Wave Weather Lower Stable Layer / Unstable / Stable Aloft Winds > 15K / Increasing with Altitude Significant geographic elevation change 90 deg is optimum Strength increases if amplified by another terrain feature in phase with primary

75. Mountain Wave System

76. 6/9/2015 Transition pilot wave sketch Lenticularcular Rotor

77. 6/9/2015 Some rotor research in progress

78. 6/9/2015 Some rotor research in progress

82. Thermal Predictors/Indicators Negative Thermal Index values at alt. Forecast plots Clouds Birds – Eagles & Hawks see in the Infrared Gliders circling – Most expensive Variometer ever invented (another sailplane) Dirt, crops, houses, animals rising before your eyes

83. Seasonal Weather Operations Density Altitude Increases with Temp Thunderstorms – Spring & Fall Temperature extremes Wind shear Microbursts Foliage & Ground Cover –Ground Temperature at start of day Frost, Snow Ice

84. Determining When to Land What effect does the wind have on landing? Why Fly a Pattern? Unplanned for Crosswinds account for over 30% of landing accidents

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

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

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

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

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

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

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

93. 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 (when 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)

94. Glide Distance L/DHeightdistance 8100800 1267800 2040800 2730800

95. With 20K Headwind

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

97. Transition through Wind Shear Line Speed (kts) Time (s) Alt Remaining (ft) Distance (ft) 600100800 50189867 40270934

98. Final Approach (20 Kt Wind Shear) 2400 200 2 seconds for the glider to stabilize at the new sink rate AOA increases from 0.5 o to 5.0 o 1600 20 kts 0 kts 934

99. Distance & Altitude during recovery phase Speed (kts) Time (s) Alt Remaining (ft) Distance (ft) 40070934 471561012 532311110 603-51230

101. Final Approach (20 Kt Wind Shear) 2400 200 3 seconds to accelerate back to 60 Kts Glider nose is 20 o below the horizon 1600 20 kts 0 kts 1230

102. Final Approach (Likely outcome in 3 cases?) 2400 200 16001230 No Wind Constant headwind 20 Kt Wind Shear

103. Shear Encounters When can this happen? –Landing in gusty conditions –Landing area shielded by obstructions –During good thermal conditions (backside of a passing thermal)

104. Recommendations Plan for this loss of energy –Pick an approach speed that will allow for some loss –Move base leg closer to runway edge –Be higher turning Final –Be prepared to close the spoilers –Be prepared to pitch forward to maintain/recover airspeed

105. Conclusions Shear line causes loss of Total Energy Large Pitch change required to rapidly recover lost energy Large amount of Time ‘lost’ while total energy changes Immediate action is required to reach original touchdown point!

106. Effects on Landing Steady wind requires more energy –800 feet closer or 100 ft higher for 20 kt wind Changing wind requires more energy Sink requires more energy Ask yourself “Are you more likely to wind up getting low or high on final?”

107. SO … What have you Learned?