Soaring Guidance
Issued by NWS Pueblo, CO
Issued by NWS Pueblo, CO
602 UXUS97 KPUB 161228 SRGPUB Soaring Forecast National Weather Service Pueblo, Colorado 0628 MDT Friday, August 16, 2024 This forecast is for Villa Grove, CO for Friday, August 16, 2024: If the trigger temperature of 68.3 F/20.2 C is reached...then Thermal Soaring Index....................... Excellent Maximum rate of lift........................ 1253 ft/min (6.4 m/s) Maximum height of thermals.................. 22093 ft MSL (13123 ft AGL) Forecast maximum temperature................... 83.0 F/28.8 C Time of trigger temperature.................... 0945 MDT Time of overdevelopment........................ None Middle/high clouds during soaring window....... None Surface winds during soaring window............ 20 mph or less Height of the -3 thermal index................. 18131 ft MSL (9161 ft AGL) Thermal soaring outlook for Saturday 08/17..... Excellent Wave Soaring Index............................. Not available Remarks... Sunrise/Sunset.................... 06:19:58 / 19:55:27 MDT Total possible sunshine........... 13 hr 35 min 30 sec (815 min 30 sec) Altitude of sun at 13:07:42 MDT... 65.06 degrees Upper air data from numerical model forecast valid on 08/16/2024 at 0600 MDT Freezing level.................. 16519 ft MSL (7549 ft AGL) Convective condensation level... 20254 ft MSL (11284 ft AGL) Lifted condensation level....... 20916 ft MSL (11945 ft AGL) Lifted index.................... -3.4 K index......................... -11.2 Height Temperature Wind Wind Spd Lapse Rate ConvectionT Thermal Lift Rate ft MSL deg C deg F Dir kt m/s C/km F/kft deg C deg F Index fpm m/s -------------------------------------------------------------------------------- 50000 -63.9 -83.0 270 24 12 1.4 0.8 M M M M M 45000 -59.3 -74.7 275 39 20 6.2 3.4 M M M M M 40000 -49.5 -57.1 290 48 25 6.2 3.4 M M M M M 38000 -45.8 -50.4 285 50 26 6.2 3.4 M M M M M 36000 -42.1 -43.8 285 53 27 6.7 3.7 M M M M M 34000 -37.6 -35.7 285 51 26 7.4 4.1 M M M M M 32000 -33.2 -27.8 290 50 26 7.6 4.2 M M M M M 30000 -29.5 -21.1 290 46 24 6.1 3.4 35.0 95.0 5.3 M M 29000 -27.7 -17.9 290 44 22 6.1 3.4 33.7 92.7 4.3 M M 28000 -25.8 -14.4 290 41 21 7.5 4.1 32.6 90.6 3.4 M M 27000 -22.8 -9.0 285 38 20 8.0 4.4 31.6 88.9 2.7 M M 26000 -20.4 -4.7 285 36 18 8.0 4.4 31.0 87.8 2.2 M M 25000 -18.0 -0.4 285 34 17 7.8 4.3 30.4 86.8 1.8 M M 24000 -15.7 3.7 285 34 18 7.7 4.2 29.6 85.3 1.1 M M 23000 -13.5 7.7 285 35 18 7.7 4.2 28.9 84.0 0.5 M M 22000 -11.1 12.0 285 35 18 7.9 4.4 28.3 82.9 -0.1 1241 6.3 21000 -8.7 16.3 285 36 19 8.0 4.4 27.6 81.7 -0.7 1140 5.8 20000 -6.3 20.7 285 37 19 8.0 4.4 27.0 80.7 -1.2 1038 5.3 19500 -5.1 22.8 285 38 20 7.6 4.2 26.8 80.2 -1.4 988 5.0 19000 -4.2 24.4 285 36 19 5.8 3.2 26.2 79.2 -1.9 944 4.8 18500 -3.3 26.1 280 34 18 5.9 3.3 25.6 78.1 -2.5 903 4.6 18000 -2.5 27.5 275 32 17 5.3 2.9 25.0 76.9 -3.1 863 4.4 17500 -1.7 28.9 270 30 16 5.2 2.8 24.2 75.5 -3.9 826 4.2 17000 -1.0 30.2 265 28 15 5.4 3.0 23.4 74.2 -4.6 790 4.0 16500 -0.1 31.8 260 28 14 6.8 3.7 22.9 73.2 -5.2 748 3.8 16000 0.8 33.4 260 28 14 6.8 3.7 22.4 72.3 -5.8 705 3.6 15500 1.8 35.2 260 28 15 7.4 4.1 22.0 71.5 -6.3 661 3.4 15000 2.9 37.2 260 28 15 7.6 4.2 21.6 70.9 -6.7 614 3.1 14500 4.0 39.2 265 28 15 8.2 4.5 21.3 70.3 -7.1 567 2.9 14000 5.8 42.4 265 27 14 8.4 4.6 21.0 69.7 -7.5 490 2.5 13500 7.1 44.8 265 26 13 10.3 5.7 20.9 69.6 -7.7 437 2.2 13000 8.4 47.1 265 25 13 8.1 4.4 20.8 69.4 -7.9 382 1.9 12500 9.7 49.5 265 25 13 9.4 5.1 20.6 69.1 -8.1 329 1.7 12000 11.1 52.0 270 25 13 9.0 5.0 20.6 69.2 -8.2 272 1.4 11750 11.7 53.1 270 25 13 8.1 4.4 20.5 68.9 -8.3 246 1.3 11500 12.3 54.1 270 25 13 8.5 4.6 20.4 68.8 -8.5 221 1.1 11250 12.9 55.2 270 24 12 8.6 4.7 20.3 68.6 -8.6 195 1.0 11000 13.5 56.3 270 23 12 8.2 4.5 20.2 68.4 -8.8 169 0.9 10750 14.2 57.6 270 22 11 10.2 5.6 20.2 68.3 -8.9 143 0.7 10500 14.9 58.8 275 21 11 5.7 3.1 20.1 68.3 -9.0 115 0.6 10250 14.9 58.8 270 20 10 1.0 0.6 19.5 67.1 -9.7 106 0.5 10000 15.0 59.0 270 18 9 0.3 0.2 18.9 66.0 -10.4 97 0.5 9750 15.0 59.0 270 17 9 7.8 4.3 18.3 65.0 -11.1 89 0.5 9500 15.4 59.7 265 15 8 -4.5 -2.5 18.1 64.6 -11.4 68 0.3 9250 13.4 56.1 260 10 5 -47.7 -26.2 15.4 59.7 -14.2 121 0.6 9000 11.4 52.5 245 5 3 35.8 19.7 12.7 54.8 -16.9 174 0.9 8750 M M M M M M M M M M M M 8500 M M M M M M M M M M M M 8250 M M M M M M M M M M M M 8000 M M M M M M M M M M M M * * * * * * Numerical weather prediction model forecast data valid * * * * * * 08/16/2024 at 0900 MDT | 08/16/2024 at 1200 MDT | CAPE... +77.2 LI... +1.8 | CAPE... +161.7 LI... +0.4 CINH... -107.2 K Index... -7.9 | CINH... -21.9 K Index... -4.3 | Height Temperature Wnd WndSpd Lapse Rate | Temperature Wnd WndSpd Lapse Rate ft MSL deg C deg F Dir kt m/s C/km F/kft | deg C deg F Dir kt m/s C/km F/kft -------------------------------------------------------------------------------- 50000 -64.5 -84.1 270 28 15 0.3 0.2 | -64.0 -83.2 285 25 13 0.2 0.1 45000 -60.5 -76.9 275 43 22 7.1 3.9 | -60.4 -76.7 285 43 22 6.6 3.6 40000 -49.5 -57.1 285 46 24 6.2 3.4 | -50.2 -58.4 280 49 25 6.2 3.4 38000 -45.8 -50.4 285 48 25 6.2 3.4 | -46.4 -51.5 280 48 25 6.3 3.4 36000 -42.1 -43.8 280 49 25 6.9 3.8 | -42.7 -44.9 280 48 25 6.7 3.7 34000 -37.7 -35.9 285 45 23 7.4 4.1 | -38.4 -37.1 280 42 21 7.2 3.9 32000 -33.2 -27.8 290 42 22 7.5 4.1 | -34.1 -29.4 280 36 18 7.3 4.0 30000 -29.4 -20.9 290 38 19 6.3 3.5 | -29.7 -21.5 275 31 16 7.4 4.1 29000 -27.5 -17.5 290 35 18 6.3 3.5 | -26.9 -16.4 275 29 15 7.4 4.1 28000 -25.6 -14.1 290 33 17 7.6 4.2 | -24.6 -12.3 275 27 14 7.9 4.3 27000 -22.6 -8.7 285 30 15 7.8 4.3 | -22.2 -8.0 270 26 13 7.9 4.3 26000 -20.3 -4.5 280 28 14 7.8 4.3 | -19.9 -3.8 265 24 13 7.9 4.3 25000 -18.0 -0.4 275 26 13 7.2 4.0 | -17.6 0.3 265 24 12 6.3 3.5 24000 -15.9 3.4 280 26 13 7.1 3.9 | -15.8 3.6 265 24 12 6.0 3.3 23000 -13.7 7.3 280 26 14 7.1 3.9 | -14.0 6.8 270 24 12 6.0 3.3 22000 -11.6 11.1 280 27 14 8.0 4.4 | -12.1 10.2 275 24 12 8.1 4.4 21000 -9.2 15.4 280 28 14 8.1 4.5 | -9.6 14.7 275 25 13 8.3 4.6 20000 -6.7 19.9 280 29 15 8.2 4.5 | -7.1 19.2 275 26 14 8.3 4.6 19500 -5.5 22.1 275 30 15 8.3 4.6 | -5.9 21.4 270 27 14 8.3 4.6 19000 -4.2 24.4 275 30 15 8.8 4.8 | -4.7 23.5 270 27 14 8.3 4.5 18500 -2.9 26.8 275 30 16 8.9 4.9 | -3.4 25.9 270 28 14 8.4 4.6 18000 -1.7 28.9 275 31 16 6.7 3.7 | -2.3 27.9 270 28 15 6.6 3.6 17500 -0.7 30.7 270 30 16 6.4 3.5 | -1.4 29.5 270 30 15 6.5 3.5 17000 0.2 32.4 270 30 15 5.8 3.2 | -0.4 31.3 270 31 16 6.7 3.7 16500 0.9 33.6 270 29 15 4.1 2.3 | 0.6 33.1 270 31 16 7.4 4.0 16000 1.4 34.5 270 28 14 4.4 2.4 | 1.6 34.9 270 30 16 7.6 4.2 15500 2.1 35.8 270 28 14 6.1 3.3 | 2.6 36.7 270 29 15 7.4 4.0 15000 2.9 37.2 270 28 14 6.2 3.4 | 3.6 38.5 270 26 14 7.8 4.3 14500 3.7 38.7 270 28 14 7.1 3.9 | 5.2 41.4 270 23 12 9.3 5.1 14000 4.9 40.8 270 29 15 9.0 4.9 | 6.6 43.9 270 20 10 9.4 5.2 13500 6.8 44.2 270 29 15 10.8 5.9 | 8.1 46.6 270 18 9 10.9 6.0 13000 8.2 46.8 270 29 15 8.8 4.8 | 9.5 49.1 270 18 9 8.9 4.9 12500 9.6 49.3 270 28 14 9.8 5.4 | 10.9 51.6 270 18 9 10.4 5.7 12000 11.1 52.0 270 26 13 9.1 5.0 | 12.5 54.5 270 17 9 9.5 5.2 11750 11.7 53.1 275 26 13 8.1 4.5 | 13.2 55.8 270 17 9 8.7 4.8 11500 12.3 54.1 275 25 13 8.6 4.7 | 13.8 56.8 270 17 9 9.9 5.4 11250 13.0 55.4 275 24 13 8.7 4.8 | 14.6 58.3 265 16 8 10.4 5.7 11000 13.6 56.5 275 24 12 8.6 4.7 | 15.4 59.7 265 16 8 10.3 5.6 10750 14.3 57.7 275 23 12 9.5 5.2 | 16.1 61.0 265 16 8 10.6 5.8 10500 14.9 58.8 270 22 11 6.3 3.5 | 16.9 62.4 265 16 8 10.9 6.0 10250 15.2 59.4 270 19 10 3.1 1.7 | 17.7 63.9 265 15 8 10.8 5.9 10000 15.4 59.7 270 17 9 4.1 2.3 | 18.6 65.5 265 15 8 11.3 6.2 9750 15.6 60.1 265 15 8 3.5 1.9 | 19.4 66.9 265 14 7 9.3 5.1 9500 15.9 60.6 265 13 7 8.4 4.6 | 20.1 68.2 265 14 7 15.5 8.5 9250 16.8 62.2 260 10 5 17.3 9.5 | 21.9 71.4 265 13 7 31.8 17.4 9000 17.7 63.9 245 7 3 1.5 0.8 | 23.6 74.5 265 11 6 1.2 0.7 8750 M M M M M M M | M M M M M M M 8500 M M M M M M M | M M M M M M M 8250 M M M M M M M | M M M M M M M 8000 M M M M M M M | M M M M M M M 08/16/2024 at 1500 MDT | 08/16/2024 at 1800 MDT | CAPE... +494.3 LI... -1.4 | CAPE... +564.6 LI... -1.9 CINH... -0.9 K Index... +21.9 | CINH... -14.6 K Index... +23.4 | Height Temperature Wnd WndSpd Lapse Rate | Temperature Wnd WndSpd Lapse Rate ft MSL deg C deg F Dir kt m/s C/km F/kft | deg C deg F Dir kt m/s C/km F/kft -------------------------------------------------------------------------------- 50000 -64.3 -83.7 295 20 10 1.8 1.0 | -64.0 -83.2 290 12 6 2.5 1.4 45000 -59.7 -75.5 290 34 18 5.5 3.0 | -58.8 -73.8 280 23 12 5.3 2.9 40000 -50.8 -59.4 275 50 26 6.7 3.7 | -50.1 -58.2 275 46 23 6.6 3.6 38000 -46.8 -52.2 275 49 25 6.7 3.7 | -46.1 -51.0 275 45 23 6.6 3.6 36000 -42.8 -45.0 275 48 25 7.1 3.9 | -42.1 -43.8 275 45 23 7.1 3.9 34000 -38.4 -37.1 270 40 21 7.4 4.1 | -37.7 -35.9 280 41 21 7.4 4.0 32000 -33.9 -29.0 260 33 17 7.5 4.1 | -33.3 -27.9 280 37 19 7.4 4.0 30000 -29.5 -21.1 255 30 15 7.4 4.0 | -29.2 -20.6 280 36 19 6.7 3.7 29000 -27.3 -17.1 255 28 14 7.4 4.0 | -26.7 -16.1 280 35 18 6.8 3.7 28000 -24.6 -12.3 255 27 14 7.1 3.9 | -24.6 -12.3 275 35 18 7.0 3.9 27000 -22.5 -8.5 260 27 14 7.1 3.9 | -22.5 -8.5 275 35 18 7.0 3.9 26000 -20.4 -4.7 265 28 14 7.1 3.9 | -20.4 -4.7 275 35 18 7.0 3.9 25000 -18.3 -0.9 265 29 15 6.3 3.4 | -18.4 -1.1 275 34 18 6.6 3.6 24000 -16.5 2.3 270 29 15 6.2 3.4 | -16.4 2.5 275 33 17 6.5 3.6 23000 -14.6 5.7 275 30 15 6.2 3.4 | -14.5 5.9 275 31 16 6.5 3.6 22000 -12.7 9.1 275 30 15 8.3 4.6 | -12.5 9.5 280 29 15 8.3 4.6 21000 -10.2 13.6 275 29 15 8.5 4.7 | -10.0 14.0 280 24 13 8.5 4.6 20000 -7.7 18.1 275 28 14 8.6 4.7 | -7.6 18.3 280 20 10 8.6 4.7 19500 -6.5 20.3 270 27 14 8.2 4.5 | -6.4 20.5 280 18 9 8.8 4.8 19000 -5.4 22.3 270 25 13 7.9 4.3 | -5.1 22.8 280 17 9 9.0 4.9 18500 -4.4 24.1 270 23 12 8.1 4.4 | -3.8 25.2 285 16 8 9.0 4.9 18000 -3.2 26.2 270 21 11 9.3 5.1 | -2.5 27.5 285 14 7 9.3 5.1 17500 -1.9 28.6 265 18 9 9.3 5.1 | -1.2 29.8 285 13 7 9.3 5.1 17000 -0.6 30.9 265 16 8 9.5 5.2 | 0.2 32.4 285 12 6 9.2 5.1 16500 0.8 33.4 265 15 8 9.7 5.3 | 1.5 34.7 280 11 6 9.1 5.0 16000 2.2 36.0 265 15 8 9.7 5.3 | 2.8 37.0 280 11 6 9.0 4.9 15500 3.7 38.7 265 14 7 9.6 5.3 | 4.2 39.6 275 10 5 9.8 5.4 15000 5.1 41.2 265 14 7 9.7 5.3 | 5.6 42.1 275 10 5 9.8 5.4 14500 7.2 45.0 265 13 7 9.8 5.4 | 7.6 45.7 270 9 5 9.3 5.1 14000 8.7 47.7 265 13 7 9.7 5.3 | 9.0 48.2 265 9 5 9.5 5.2 13500 10.3 50.5 265 13 7 11.4 6.3 | 10.4 50.7 260 9 5 9.5 5.2 13000 11.7 53.1 265 13 7 8.5 4.7 | 11.7 53.1 255 9 5 8.7 4.8 12500 13.1 55.6 265 13 6 10.7 5.9 | 13.0 55.4 250 9 5 8.7 4.8 12000 14.7 58.5 265 12 6 9.8 5.4 | 14.3 57.7 245 10 5 8.7 4.8 11750 15.4 59.7 265 12 6 9.2 5.0 | 14.9 58.8 240 10 5 8.6 4.7 11500 16.1 61.0 265 12 6 9.4 5.2 | 15.5 59.9 235 10 5 8.3 4.5 11250 16.8 62.2 265 12 6 9.4 5.1 | 16.1 61.0 235 10 5 8.0 4.4 11000 17.5 63.5 265 12 6 9.4 5.2 | 16.7 62.1 230 11 5 8.1 4.5 10750 18.2 64.8 265 12 6 10.7 5.9 | 17.3 63.1 230 11 6 9.1 5.0 10500 19.1 66.4 265 11 6 11.0 6.0 | 18.0 64.4 230 11 6 10.1 5.5 10250 19.8 67.6 265 11 6 10.2 5.6 | 18.8 65.8 225 11 6 10.0 5.5 10000 20.6 69.1 265 11 6 10.7 5.9 | 19.5 67.1 225 11 6 10.3 5.7 9750 21.4 70.5 265 11 5 9.6 5.2 | 20.2 68.4 225 11 5 9.0 4.9 9500 22.2 72.0 265 10 5 16.3 9.0 | 20.9 69.6 225 11 5 11.8 6.5 9250 23.9 75.0 265 10 5 30.5 16.8 | 22.1 71.8 225 9 5 20.2 11.1 9000 25.7 78.3 265 9 5 4.6 2.5 | 23.2 73.8 225 8 4 4.1 2.2 8750 M M M M M M M | M M M M M M M 8500 M M M M M M M | M M M M M M M 8250 M M M M M M M | M M M M M M M 8000 M M M M M M M | M M M M M M M ________________________________________________________________________________ This product is issued twice per day, once by approximately 0630 MST/0730 MDT (1330 UTC). It is not continuously monitored nor updated after its initial issuance. The information contained herein is based on rawinsonde observation and/or numerical weather prediction model data taken near Villa Grove, Colorado at: North Latitude: 38 deg 16 min 03 sec West Longitude: 105 deg 53 min 37 sec Elevation: 7986 feet (2434 meters) and may not be representative of other areas along the Front Range of the Colorado Rocky Mountains. Note that some elevations in numerical weather prediction models differ from actual station elevations, which can lead to data which appear to be below ground. Erroneous data such as these should not be used. The content and format of this report as well as the issuance times are subject to change without prior notice. Comments and suggestions are welcome and should be directed to one of the addresses or phone numbers shown at the bottom of this page. To expedite a response to comments, be sure to mention your interest in the soaring forecast. DEFINITIONS: CAPE (Convective Available Potential Energy) - An integrated measure of the energy available for convective development, also known as the positive area on a thermodynamic diagram. Units are Joules per kilogram. Larger values are indicative of greater instability and the possibility of stronger convective activity, including thunderstorms. Values around or greater than 1000 suggest the possibility of severe weather should convective activity develop. CIN (Convective Inhibition) - An integrated measure of the amount of energy needed to initiate convective activity, also known as the negative area on a thermodynamic diagram. Units are Joules per kilogram. The more negative this number, the more energy is required to initiate convection. This inhibitive energy can be overcome through surface heating, cooling aloft, lifting mechanisms (orographic, frontal, gravity waves, etc.) Convective Condensation Level - The height to which an air parcel possessing the average saturation mixing ratio in the lowest 4000 feet of the airmass, if heated sufficiently from below, will rise dry adiabatically until it just becomes saturated. It estimates the base of cumulus clouds that are produced by surface heating only. Convection Temperature (ConvectionT) - The surface temperature required to make the airmass dry adiabatic up to the given level. It can be considered a "trigger temperature" for that level. Freezing Level - The height where the temperature is zero degrees Celsius. Height of Stable Layer - The height (between 12,000 and 18,000 feet above mean sea level) where the smallest lapse rate exists. The location and existence of this feature is important in the generation of mountain waves. K Index - A measure of stability which combines the temperature difference between approximately 5,000 and 18,000 feet above the surface, the amount of moisture at approximately 5,000 feet above the surface, and a measure of the dryness at approximately 10,000 feet above the surface. Larger positive numbers indicate more instability and a greater likelihood of thunderstorm development. One interpretation of K index values regarding soaring in the western United States is given in WMO Technical Note 158 and is reproduced in the following table: below -10 no or weak thermals -10 to 5 dry thermals or 1/8 cumulus with moderate thermals 5 to 15 good soaring conditions 15 to 20 good soaring conditions with occasional showers 20 to 30 excellent soaring conditions, but increasing probability of showers and thunderstorms above 30 more than 60 percent probability of thunderstorms Lapse Rate - The change with height of the temperature. Negative values indicate inversions. Lifted Condensation Level - The height to which an air parcel possessing the average dew point in the lowest 4000 feet of the airmass and the forecast maximum temperature must be lifted dry adiabatically to attain saturation. Lifted Index (LI) - The difference between the environmental temperature at a level approximately 18,000 feet above the surface and the temperature of an air parcel lifted dry adiabatically from the surface to its lifted condensation level and then pseudoadiabatically thereafter to this same level. The parcel`s initial temperature is the forecast maximum temperature and its dew point is the average dew point in the lowest 4000 feet of the airmass. Negative values are indicative of instability with positive values showing stable conditions. Lift Rate - An experimental estimate of the strength of thermals. It is computed the same way as the maximum rate of lift but uses the actual level rather than the maximum height of thermals in the calculation. Also, none of the empirical adjustments based on cloudiness and K-index are applied to these calculations. Maximum Height of Thermals - The height where the dry adiabat through the forecast maximum temperature intersects the environmental temperature. Maximum Rate of Lift - An estimate of the maximum strength of thermals. It is computed from an empirical formula which combines the expected maximum height of thermals with the difference in the environmental temperatures between the maximum height of thermals and the temperature 4,000 feet above the ground. After this computation, further empirical adjustments are made based on the value of the K-index and the amount and opacity of middle and high level cloudiness expected between the time of trigger temperature and the time of overdevelopment. Middle/High Clouds - The amount and opacity of middle (altostratus, altocumulus) or high (cirrus, cirrostratus, cirrocumulus) clouds. Broken means that between 60% and 90% of the sky is covered by the cloud, with overcast conditions occurring when more than 90% of the sky is covered by the cloud. Thin implies that the clouds are predominantly transparent, meaning that some sunlight is reaching the ground, in contrast to opaque which suggests that little sunlight is reaching the ground. Potential Height of Wave - The minimum of the following two heights: 1. Level above the height of stable layer (or 14,000 feet if none exists) where the wind direction changes by 30 degrees or more 2. Level above the height of stable layer (or 14,000 feet if none exists) where the wind speed no longer increases with height PVA/NVA - Positive vorticity advection (PVA)/negative vorticity advection (NVA) on the 500 millibar isobaric surface (approximately 18,000 feet above mean sea level). Weak PVA has been shown to assist in mountain wave soaring. Soaring Window - The time between the time the trigger temperature is reached and the time of overdevelopment. Thermal Index - The difference between the environmental temperature and the temperature at a particular level determined by following the dry adiabat through the forecast maximum temperature up to that level. Negative values are indicative of thermal lift. Thermal Soaring Index - An adjective rating (for sailplanes) based on the computed maximum rate of lift, and the wind speed and middle and high cloud cover expected during the soaring window (the time of the trigger temperature and the time of overdevelopment) according to the following: Maximum rate of lift Adjective Rating >= 800 fpm Excellent >= 400 and < 800 fpm Good >= 200 and < 400 fpm Fair < 200 fpm Poor Time of Overdevelopment - The time one or more of the following phenomena, which essentially shut off thermal lift, is expected to occur: 1. formation of broken to overcast convective cloud cover 2. formation of scattered to numerous downbursts 3. initiation of widespread precipitation Time of Trigger Temperature - The time the surface temperature is expected to reach the trigger temperature. Trigger Temperature - The surface temperature required to make the first 4000 feet of the atmosphere dry adiabatic. Wave Soaring Index - An empirical, adjective rating (for sailplanes) which attempts to combine a variety of phenomena important in mountain wave soaring into a single index number. Objective points are assigned to these phenomena: wind speed and direction at 14,000 ft MSL, the static stability in the 12,000-18,000 ft MSL layer, the wind speed gradient above the stable layer, jet stream location and frontal and upper trough movements. 042613