Soaring Guidance
Issued by NWS Pueblo, CO
Issued by NWS Pueblo, CO
549 UXUS97 KPUB 301233 SRGPUB Soaring Forecast National Weather Service Pueblo, Colorado 0633 MDT Sunday, June 30, 2024 This forecast is for Villa Grove, CO for Sunday, June 30, 2024: If the trigger temperature of 64.1 F/17.8 C is reached...then Thermal Soaring Index....................... Fair Maximum rate of lift........................ 393 ft/min (2.0 m/s) Maximum height of thermals.................. 18076 ft MSL (9080 ft AGL) Forecast maximum temperature................... 77.0 F/25.5 C Time of trigger temperature.................... 1045 MDT Time of overdevelopment........................ None Middle/high clouds during soaring window....... Broken/overcast opaque middle Surface winds during soaring window............ 20 mph or less Height of the -3 thermal index................. 15929 ft MSL (6933 ft AGL) Thermal soaring outlook for Monday 07/01....... Good Wave Soaring Index............................. Not available Remarks... Sunrise/Sunset.................... 05:43:52 / 20:31:00 MDT Total possible sunshine........... 14 hr 47 min 8 sec (887 min 8 sec) Altitude of sun at 13:07:26 MDT... 74.75 degrees Upper air data from numerical model forecast valid on 06/30/2024 at 0600 MDT Freezing level.................. 16624 ft MSL (7628 ft AGL) Convective condensation level... 13753 ft MSL (4757 ft AGL) Lifted condensation level....... 16295 ft MSL (7299 ft AGL) Lifted index.................... -3.7 K index......................... +23.7 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 -64.9 -84.8 270 25 13 3.4 1.8 M M M M M 45000 -58.5 -73.3 245 34 18 5.4 3.0 M M M M M 40000 -49.2 -56.6 215 47 24 9.1 5.0 M M M M M 38000 -43.7 -46.7 215 46 23 9.1 5.0 M M M M M 36000 -38.3 -36.9 210 44 23 7.8 4.3 M M M M M 34000 -33.2 -27.8 220 41 21 7.5 4.1 M M M M M 32000 -28.7 -19.7 225 39 20 7.5 4.1 42.8 109.0 13.7 M M 30000 -24.9 -12.8 230 35 18 6.4 3.5 40.0 104.0 11.8 M M 29000 -23.0 -9.4 235 33 17 6.4 3.5 38.9 102.0 11.0 M M 28000 -21.1 -6.0 240 31 16 6.4 3.5 37.7 99.8 10.1 M M 27000 -19.2 -2.6 240 29 15 6.4 3.5 36.3 97.4 9.1 M M 26000 -17.3 0.9 245 27 14 6.5 3.6 35.2 95.3 8.2 M M 25000 -15.4 4.3 245 26 13 6.4 3.5 34.1 93.4 7.4 M M 24000 -13.6 7.5 245 25 13 6.3 3.5 32.8 91.0 6.3 M M 23000 -11.7 10.9 250 24 12 6.3 3.5 31.6 88.8 5.3 M M 22000 -9.9 14.2 250 23 12 6.3 3.4 30.5 86.9 4.3 M M 21000 -8.1 17.4 255 24 12 6.3 3.4 29.2 84.5 3.2 M M 20000 -6.2 20.8 255 25 13 6.3 3.5 28.0 82.5 2.1 M M 19500 -5.3 22.5 260 26 13 6.3 3.5 27.5 81.5 1.6 M M 19000 -4.4 24.1 260 25 13 6.5 3.6 26.9 80.5 1.1 M M 18500 -3.5 25.7 260 24 13 6.5 3.6 26.4 79.5 0.6 M M 18000 -2.5 27.5 260 24 12 6.3 3.5 25.9 78.6 0.0 M M 17500 -1.6 29.1 260 22 11 6.3 3.4 25.3 77.5 -0.5 755 3.8 17000 -0.3 31.5 255 20 10 5.1 2.8 24.4 75.9 -1.4 694 3.5 16500 0.3 32.5 250 19 10 4.8 2.7 23.6 74.5 -2.3 659 3.3 16000 1.0 33.8 245 19 10 5.0 2.8 22.8 73.0 -3.1 624 3.2 15500 1.8 35.2 245 17 9 5.6 3.1 22.1 71.8 -3.8 586 3.0 15000 2.5 36.5 240 16 8 5.5 3.0 21.4 70.6 -4.5 548 2.8 14500 3.4 38.1 235 16 8 6.4 3.5 20.8 69.5 -5.1 508 2.6 14000 4.3 39.7 235 16 8 6.3 3.5 20.3 68.5 -5.7 466 2.4 13500 5.1 41.2 230 16 8 5.8 3.2 19.7 67.5 -6.3 425 2.2 13000 6.0 42.8 225 17 9 6.2 3.4 19.1 66.4 -7.0 385 2.0 12500 6.8 44.2 220 18 9 5.4 2.9 18.5 65.4 -7.6 345 1.8 12000 7.5 45.5 215 21 11 5.0 2.8 17.8 64.1 -8.4 310 1.6 11750 7.9 46.2 210 21 11 4.9 2.7 17.4 63.4 -8.8 292 1.5 11500 8.2 46.8 210 21 11 4.0 2.2 17.1 62.7 -9.3 275 1.4 11250 8.4 47.1 205 21 11 3.5 1.9 16.6 61.8 -9.8 261 1.3 11000 8.6 47.5 205 21 11 3.0 1.7 16.1 61.0 -10.3 247 1.3 10750 8.9 48.0 205 21 11 5.5 3.0 15.6 60.1 -10.8 233 1.2 10500 9.4 48.9 200 19 10 7.5 4.1 15.4 59.8 -11.1 209 1.1 10250 9.8 49.6 200 18 9 6.2 3.4 15.2 59.3 -11.4 188 1.0 10000 10.3 50.5 200 16 8 7.1 3.9 14.9 58.9 -11.7 167 0.9 9750 10.7 51.3 200 15 8 5.0 2.7 14.7 58.5 -12.0 146 0.7 9500 11.0 51.8 195 13 7 1.8 1.0 14.2 57.6 -12.5 132 0.7 9250 11.2 52.2 190 9 5 2.6 1.4 13.6 56.5 -13.1 119 0.6 9000 11.3 52.3 185 5 3 -0.6 -0.3 13.0 55.5 -13.7 106 0.5 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 * * * * * * 06/30/2024 at 0900 MDT | 06/30/2024 at 1200 MDT | CAPE... +53.9 LI... -0.2 | CAPE... +831.6 LI... -2.7 CINH... -47.1 K Index... +22.1 | CINH... -1.5 K Index... +21.8 | 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 -65.3 -85.5 260 21 11 3.5 1.9 | -64.9 -84.8 235 19 10 3.0 1.6 45000 -58.3 -72.9 255 31 16 6.2 3.4 | -58.4 -73.1 240 29 15 6.2 3.4 40000 -48.5 -55.3 235 41 21 8.0 4.4 | -48.0 -54.4 235 40 21 8.1 4.4 38000 -43.7 -46.7 230 39 20 8.0 4.4 | -43.2 -45.8 230 41 21 8.1 4.4 36000 -38.9 -38.0 225 38 20 7.7 4.2 | -38.4 -37.1 225 41 21 7.4 4.1 34000 -33.7 -28.7 225 38 19 7.7 4.2 | -33.9 -29.0 225 42 22 7.4 4.1 32000 -29.1 -20.4 225 37 19 7.8 4.3 | -29.5 -21.1 225 42 22 7.6 4.2 30000 -24.9 -12.8 230 36 18 6.9 3.8 | -25.6 -14.1 230 38 19 6.7 3.7 29000 -22.9 -9.2 235 35 18 6.9 3.8 | -23.6 -10.5 230 35 18 6.7 3.7 28000 -20.9 -5.6 235 34 17 6.5 3.5 | -21.2 -6.2 235 34 18 6.5 3.6 27000 -18.9 -2.0 235 32 16 6.5 3.6 | -19.3 -2.7 235 35 18 6.5 3.6 26000 -17.0 1.4 235 30 15 6.6 3.6 | -17.3 0.9 235 37 19 6.5 3.5 25000 -15.1 4.8 235 28 15 6.5 3.6 | -15.4 4.3 235 37 19 7.2 4.0 24000 -13.2 8.2 235 28 14 6.5 3.5 | -13.2 8.2 235 34 17 7.2 3.9 23000 -11.4 11.5 235 27 14 6.5 3.6 | -11.1 12.0 235 31 16 7.2 4.0 22000 -9.5 14.9 230 26 14 6.2 3.4 | -9.1 15.6 235 29 15 6.1 3.4 21000 -7.7 18.1 240 26 13 6.1 3.4 | -7.2 19.0 240 27 14 6.2 3.4 20000 -5.9 21.4 245 25 13 6.1 3.4 | -5.4 22.3 240 25 13 6.2 3.4 19500 -5.1 22.8 245 25 13 6.0 3.3 | -4.5 23.9 240 24 12 5.9 3.2 19000 -4.2 24.4 250 24 13 5.6 3.1 | -3.8 25.2 245 24 12 5.4 3.0 18500 -3.4 25.9 250 24 12 5.6 3.1 | -3.0 26.6 245 23 12 5.4 3.0 18000 -2.6 27.3 255 23 12 6.3 3.4 | -2.2 28.0 250 23 12 6.3 3.5 17500 -1.2 29.8 255 22 11 6.5 3.6 | -1.3 29.7 250 23 12 6.4 3.5 17000 -0.3 31.5 255 20 11 6.2 3.4 | -0.4 31.3 250 23 12 6.4 3.5 16500 0.6 33.1 255 20 10 6.2 3.4 | 0.5 32.9 250 23 12 6.5 3.6 16000 1.5 34.7 255 19 10 6.4 3.5 | 1.4 34.5 250 23 12 6.5 3.5 15500 2.4 36.3 255 18 9 6.8 3.7 | 2.4 36.3 250 22 11 7.0 3.8 15000 3.4 38.1 255 18 9 6.8 3.7 | 3.9 39.0 255 21 11 6.8 3.7 14500 4.4 39.9 260 19 10 6.9 3.8 | 4.8 40.6 255 21 11 7.1 3.9 14000 5.4 41.7 255 19 10 7.1 3.9 | 5.9 42.6 255 20 10 7.7 4.2 13500 6.4 43.5 255 19 10 6.2 3.4 | 6.9 44.4 250 20 10 6.3 3.4 13000 7.3 45.1 250 20 10 6.4 3.5 | 7.9 46.2 250 19 10 8.2 4.5 12500 8.1 46.6 250 20 10 5.2 2.9 | 8.9 48.0 250 18 9 6.1 3.3 12000 8.8 47.8 240 22 11 4.6 2.5 | 9.7 49.5 245 18 9 7.8 4.3 11750 9.1 48.4 240 21 11 3.8 2.1 | 10.3 50.5 245 17 9 9.3 5.1 11500 9.3 48.7 240 21 11 1.9 1.0 | 10.9 51.6 245 15 8 6.1 3.4 11250 9.3 48.7 235 21 11 1.1 0.6 | 11.2 52.2 240 15 8 5.3 2.9 11000 9.3 48.7 235 21 11 -0.1 -0.1 | 11.5 52.7 235 14 7 4.9 2.7 10750 9.3 48.7 230 21 11 5.8 3.2 | 11.9 53.4 230 14 7 12.6 6.9 10500 10.0 50.0 230 19 10 8.2 4.5 | 13.1 55.6 235 12 6 13.9 7.6 10250 10.3 50.5 230 18 9 3.7 2.0 | 13.8 56.8 230 12 6 8.3 4.5 10000 10.6 51.1 225 16 8 5.8 3.2 | 14.5 58.1 230 11 6 10.2 5.6 9750 10.9 51.6 225 15 8 1.8 1.0 | 15.2 59.4 230 11 6 8.2 4.5 9500 10.9 51.6 215 14 7 4.6 2.5 | 15.8 60.4 220 11 6 14.5 8.0 9250 11.8 53.2 210 11 6 19.7 10.8 | 17.4 63.3 215 10 5 29.2 16.0 9000 12.6 54.7 210 8 4 -10.1 -5.6 | 18.9 66.0 215 9 5 2.1 1.1 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 06/30/2024 at 1500 MDT | 06/30/2024 at 1800 MDT | CAPE... +873.8 LI... -3.2 | CAPE... +698.5 LI... -3.3 CINH... -1.7 K Index... +26.9 | CINH... -3.1 K Index... +27.5 | 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 -65.4 -85.7 225 24 12 2.4 1.3 | -65.8 -86.4 220 29 15 2.6 1.4 45000 -59.1 -74.4 230 34 18 6.7 3.7 | -59.2 -74.6 230 36 19 6.9 3.8 40000 -48.1 -54.6 230 43 22 8.1 4.5 | -48.4 -55.1 230 42 22 8.2 4.5 38000 -43.2 -45.8 225 43 22 8.1 4.5 | -43.4 -46.1 230 44 23 8.2 4.5 36000 -38.4 -37.1 225 43 22 7.4 4.1 | -38.0 -36.4 225 45 23 7.5 4.1 34000 -33.9 -29.0 230 43 22 7.5 4.1 | -33.4 -28.1 225 45 23 7.6 4.2 32000 -29.4 -20.9 230 42 22 7.4 4.0 | -28.9 -20.0 225 45 23 6.6 3.6 30000 -25.5 -13.9 230 39 20 6.6 3.6 | -25.2 -13.4 230 41 21 6.3 3.4 29000 -23.5 -10.3 230 38 19 6.7 3.7 | -23.3 -9.9 230 40 20 6.3 3.5 28000 -21.1 -6.0 230 37 19 6.2 3.4 | -21.3 -6.3 230 39 20 6.9 3.8 27000 -19.3 -2.7 230 37 19 6.2 3.4 | -19.3 -2.7 230 38 20 6.9 3.8 26000 -17.4 0.7 230 37 19 6.2 3.4 | -17.2 1.0 230 38 19 6.9 3.8 25000 -15.5 4.1 235 37 19 7.0 3.8 | -15.1 4.8 230 37 19 6.6 3.6 24000 -13.5 7.7 230 35 18 7.0 3.8 | -13.2 8.2 230 35 18 6.6 3.6 23000 -11.5 11.3 230 33 17 7.0 3.9 | -11.2 11.8 235 32 17 6.7 3.7 22000 -9.5 14.9 230 31 16 6.6 3.6 | -9.3 15.3 235 30 16 6.2 3.4 21000 -7.6 18.3 235 29 15 6.7 3.7 | -7.6 18.3 230 29 15 6.2 3.4 20000 -5.7 21.7 240 27 14 6.8 3.8 | -5.8 21.6 230 28 14 6.3 3.5 19500 -4.8 23.4 240 26 13 6.9 3.8 | -5.0 23.0 230 27 14 6.6 3.6 19000 -3.8 25.2 240 25 13 6.9 3.8 | -4.0 24.8 230 27 14 7.1 3.9 18500 -2.8 27.0 245 24 13 6.9 3.8 | -3.0 26.6 230 26 13 7.2 3.9 18000 -1.8 28.8 245 24 12 6.8 3.7 | -2.0 28.4 230 25 13 7.3 4.0 17500 -0.8 30.6 245 24 12 6.8 3.7 | -0.4 31.3 230 23 12 7.3 4.0 17000 0.2 32.4 245 24 12 6.9 3.8 | 0.6 33.1 230 21 11 7.8 4.3 16500 1.2 34.2 245 23 12 6.9 3.8 | 1.7 35.1 230 20 10 7.8 4.3 16000 2.1 35.8 245 22 11 6.9 3.8 | 2.9 37.2 230 18 9 8.0 4.4 15500 3.2 37.8 245 21 11 7.5 4.1 | 4.0 39.2 225 17 9 8.2 4.5 15000 4.7 40.5 240 19 10 6.6 3.6 | 5.2 41.4 225 17 9 8.0 4.4 14500 5.6 42.1 235 18 9 8.4 4.6 | 6.4 43.5 215 16 8 9.0 4.9 14000 6.9 44.4 230 17 9 9.1 5.0 | 7.7 45.9 220 16 8 9.4 5.2 13500 8.0 46.4 230 16 8 7.5 4.1 | 9.1 48.4 215 15 8 9.1 5.0 13000 9.4 48.9 225 16 8 10.4 5.7 | 10.5 50.9 215 14 7 9.5 5.2 12500 10.7 51.3 225 15 8 9.0 4.9 | 11.9 53.4 220 14 7 10.4 5.7 12000 12.0 53.6 220 15 8 10.1 5.5 | 13.4 56.1 215 13 7 9.2 5.0 11750 12.8 55.0 220 14 7 10.8 5.9 | 14.1 57.4 220 13 7 8.0 4.4 11500 13.6 56.5 220 14 7 9.7 5.3 | 14.7 58.5 220 13 7 9.5 5.2 11250 14.3 57.7 220 14 7 9.4 5.2 | 15.5 59.9 220 12 6 10.4 5.7 11000 15.0 59.0 220 14 7 9.5 5.2 | 16.2 61.2 220 12 6 10.3 5.6 10750 15.7 60.3 215 14 7 10.5 5.8 | 16.9 62.4 220 12 6 8.5 4.7 10500 16.5 61.7 220 13 7 10.9 6.0 | 17.5 63.5 220 11 6 9.2 5.0 10250 17.3 63.1 220 13 7 10.3 5.6 | 18.3 64.9 220 11 6 10.8 5.9 10000 18.1 64.6 215 13 7 10.7 5.8 | 19.1 66.4 220 11 6 11.2 6.1 9750 18.8 65.8 215 13 7 9.8 5.4 | 19.9 67.8 220 11 5 8.1 4.4 9500 19.7 67.5 220 12 6 16.4 9.0 | 20.4 68.7 220 10 5 10.4 5.7 9250 21.3 70.3 215 11 6 29.6 16.2 | 21.7 71.1 220 9 5 23.8 13.1 9000 23.0 73.4 210 10 5 5.7 3.1 | 22.9 73.2 220 8 4 -2.8 -1.5 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