


Soaring Guidance
Issued by NWS Grand Junction, CO
Issued by NWS Grand Junction, CO
196 UXUS97 KGJT 101306 SRGGJT Soaring Forecast National Weather Service Grand Junction, Colorado 706 AM MDT Friday, October 10, 2025 This forecast is for Friday, October 10, 2025: If the trigger temperature of 66.6 F/19.2 C is reached...then Thermal Soaring Index....................... Poor Maximum rate of lift........................ 178 ft/min (0.9 m/s) Maximum height of thermals.................. 10555 ft MSL (4947 ft AGL) Forecast maximum temperature................... 68.0 F/20.5 C Time of trigger temperature.................... 1245 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................. 7442 ft MSL (1834 ft AGL) Thermal soaring outlook for Saturday 10/11..... Poor Wave Soaring Index............................. Not available Remarks... Sunrise/Sunset.................... 07:19:25 / 18:42:33 MDT Total possible sunshine........... 11 hr 23 min 8 sec (683 min 8 sec) Altitude of sun at 13:00:59 MDT... 43.93 degrees Upper air data from rawinsonde observation taken on 10/10/2025 at 0600 MDT Freezing level.................. 13524 ft MSL (7916 ft AGL) Convective condensation level... 10418 ft MSL (4810 ft AGL) Lifted condensation level....... 10479 ft MSL (4871 ft AGL) Lifted index.................... +1.1 K index......................... +28.2 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 -66.3 -87.3 245 56 29 4.4 2.4 M M M M M 45000 -59.2 -74.6 245 79 41 5.6 3.1 M M M M M 40000 -50.9 -59.6 245 95 49 6.0 3.3 M M M M M 38000 -47.3 -53.1 240 89 46 5.9 3.3 M M M M M 36000 -43.7 -46.7 240 83 43 5.9 3.3 M M M M M 34000 -39.8 -39.6 235 73 38 5.8 3.2 M M M M M 32000 -36.3 -33.3 225 63 33 5.9 3.2 M M M M M 30000 -31.8 -25.2 225 56 29 8.2 4.5 43.6 110.5 17.9 M M 29000 -29.4 -20.9 225 54 28 8.3 4.5 43.1 109.5 17.7 M M 28000 -26.9 -16.4 230 51 26 8.3 4.6 42.6 108.7 17.5 M M 27000 -24.7 -12.5 230 49 25 7.5 4.1 41.7 107.1 17.0 M M 26000 -22.4 -8.3 235 47 24 7.5 4.1 40.8 105.5 16.5 M M 25000 -20.2 -4.4 235 45 23 7.4 4.1 40.1 104.1 16.0 M M 24000 -18.1 -0.6 240 43 22 6.6 3.6 39.0 102.3 15.4 M M 23000 -16.2 2.8 235 39 20 6.6 3.6 37.8 100.1 14.5 M M 22000 -14.3 6.3 230 36 18 6.6 3.6 36.7 98.1 13.7 M M 21000 -12.5 9.5 230 33 17 6.2 3.4 35.5 95.9 12.8 M M 20000 -10.7 12.7 230 32 16 6.2 3.4 34.2 93.6 11.7 M M 19500 -9.4 15.1 230 31 16 6.3 3.4 33.3 92.0 11.0 M M 19000 -8.5 16.7 230 30 15 5.5 3.0 32.7 90.9 10.5 M M 18500 -7.7 18.1 230 28 15 5.3 2.9 32.0 89.5 9.8 M M 18000 -7.0 19.4 230 27 14 5.3 2.9 31.2 88.2 9.2 M M 17500 -6.3 20.7 225 25 13 4.7 2.6 30.4 86.7 8.5 M M 17000 -5.6 21.9 225 23 12 4.8 2.6 29.5 85.2 7.7 M M 16500 -4.9 23.2 225 22 11 5.5 3.0 28.8 83.8 7.0 M M 16000 -4.1 24.6 225 21 11 5.6 3.1 28.1 82.5 6.4 M M 15500 -3.3 26.1 225 20 10 5.6 3.1 27.4 81.3 5.8 M M 15000 -2.5 27.5 225 20 10 5.6 3.1 26.7 80.0 5.2 M M 14500 -1.7 28.9 225 19 10 5.6 3.1 26.0 78.8 4.6 M M 14000 -0.8 30.6 225 19 10 6.2 3.4 25.4 77.7 4.0 M M 13500 0.1 32.2 225 19 10 6.2 3.4 24.8 76.6 3.4 M M 13000 1.0 33.8 220 19 10 6.1 3.3 24.2 75.6 2.8 M M 12500 1.8 35.2 220 19 10 6.1 3.4 23.6 74.5 2.3 M M 12000 2.7 36.9 220 19 10 6.1 3.4 23.0 73.5 1.7 M M 11500 3.6 38.5 220 19 10 6.1 3.4 22.5 72.4 1.1 M M 11000 4.4 39.9 215 18 9 6.2 3.4 21.9 71.4 0.5 M M 10500 5.3 41.5 215 17 9 6.7 3.7 21.3 70.4 -0.0 376 1.9 10250 5.8 42.4 215 17 9 7.6 4.1 21.1 70.1 -0.2 352 1.8 10000 6.4 43.5 215 16 8 7.4 4.0 21.0 69.7 -0.4 329 1.7 9750 6.9 44.4 210 16 8 7.3 4.0 20.8 69.4 -0.6 306 1.6 9500 7.4 45.3 210 15 8 7.4 4.1 20.6 69.0 -0.8 282 1.4 9250 8.0 46.4 210 15 8 7.2 3.9 20.4 68.7 -1.0 259 1.3 9000 8.5 47.3 205 14 7 6.7 3.7 20.2 68.3 -1.2 237 1.2 8750 9.0 48.2 205 14 7 6.7 3.7 19.9 67.9 -1.5 215 1.1 8500 9.5 49.1 200 13 7 6.7 3.7 19.7 67.5 -1.7 193 1.0 8250 9.9 49.8 200 13 7 6.8 3.7 19.5 67.1 -2.0 170 0.9 8000 10.4 50.7 195 13 7 6.5 3.5 19.2 66.6 -2.2 148 0.8 7750 10.9 51.6 190 12 6 6.4 3.5 19.0 66.2 -2.5 128 0.6 7500 11.3 52.3 185 12 6 5.8 3.2 18.7 65.7 -2.8 107 0.5 7250 11.7 53.1 175 12 6 3.1 1.7 18.3 65.0 -3.2 89 0.5 7000 11.8 53.2 170 13 7 3.6 2.0 17.8 64.0 -3.7 77 0.4 6750 12.2 54.0 165 13 7 5.7 3.1 17.4 63.4 -4.1 59 0.3 6500 12.5 54.5 160 13 6 3.9 2.2 17.1 62.7 -4.5 41 0.2 6250 12.7 54.9 155 11 6 1.6 0.9 16.5 61.8 -5.1 28 0.1 6000 12.9 55.2 150 9 5 4.5 2.4 16.0 60.8 -5.6 15 0.1 5750 13.3 55.9 145 8 4 6.9 3.8 15.7 60.3 -5.9 M M 5500 M M M M M M M M M M M M 5250 M M M M M M M M M M M M 5000 M M M M M M M M M M M M * * * * * * Numerical weather prediction model forecast data valid * * * * * * 10/10/2025 at 0900 MDT | 10/10/2025 at 1200 MDT | CAPE... +0.9 LI... -0.5 | CAPE... +259.6 LI... -1.5 CINH... -1.3 K Index... +28.5 | CINH... -2.3 K Index... +27.8 | 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 -67.3 -89.1 250 52 27 3.3 1.8 | -67.0 -88.6 250 52 27 4.0 2.2 45000 -60.3 -76.5 255 77 40 7.0 3.8 | -59.6 -75.3 255 75 39 6.3 3.5 40000 -50.3 -58.5 250 79 41 4.6 2.5 | -50.3 -58.5 245 82 42 5.0 2.7 38000 -47.5 -53.5 245 69 36 4.6 2.5 | -47.3 -53.1 240 73 37 5.0 2.7 36000 -44.7 -48.5 240 61 31 4.3 2.4 | -44.4 -47.9 230 64 33 4.7 2.6 34000 -40.5 -40.9 235 55 28 7.5 4.1 | -40.0 -40.0 225 58 30 7.6 4.1 32000 -35.9 -32.6 230 50 26 7.3 4.0 | -35.5 -31.9 220 52 27 7.4 4.0 30000 -31.0 -23.8 235 45 23 8.5 4.7 | -30.7 -23.3 220 48 24 8.3 4.5 29000 -28.5 -19.3 235 42 22 8.5 4.7 | -28.2 -18.8 225 46 23 8.3 4.6 28000 -25.9 -14.6 235 39 20 8.2 4.5 | -25.7 -14.3 225 44 22 8.0 4.4 27000 -23.1 -9.6 235 36 19 7.6 4.2 | -23.1 -9.6 230 40 20 7.0 3.8 26000 -20.8 -5.4 240 34 17 7.6 4.2 | -21.0 -5.8 230 37 19 7.0 3.9 25000 -18.6 -1.5 240 31 16 7.2 4.0 | -18.9 -2.0 230 33 17 6.9 3.8 24000 -16.7 1.9 240 30 15 6.2 3.4 | -17.1 1.2 230 31 16 6.3 3.5 23000 -14.9 5.2 240 29 15 6.3 3.4 | -15.2 4.6 230 28 14 6.3 3.5 22000 -13.1 8.4 240 27 14 6.1 3.3 | -13.4 7.9 230 25 13 6.1 3.3 21000 -11.4 11.5 235 27 14 5.9 3.2 | -11.7 10.9 230 25 13 5.6 3.1 20000 -9.7 14.5 230 28 14 5.9 3.2 | -10.0 14.0 230 25 13 5.6 3.1 19500 -8.8 16.2 230 28 15 5.9 3.2 | -9.2 15.4 235 24 13 5.6 3.0 19000 -8.0 17.6 230 29 15 5.5 3.0 | -8.3 17.1 235 25 13 6.5 3.6 18500 -7.2 19.0 230 29 15 5.6 3.1 | -7.4 18.7 235 25 13 6.4 3.5 18000 -6.4 20.5 230 29 15 5.7 3.1 | -6.5 20.3 235 26 13 6.4 3.5 17500 -5.6 21.9 230 29 15 5.8 3.2 | -5.5 22.1 235 26 13 6.4 3.5 17000 -4.7 23.5 230 29 15 5.9 3.2 | -4.6 23.7 235 26 13 6.5 3.6 16500 -3.9 25.0 230 29 15 5.7 3.1 | -3.8 25.2 235 26 13 5.5 3.0 16000 -3.1 26.4 230 29 15 5.7 3.1 | -3.0 26.6 235 26 13 5.6 3.1 15500 -2.2 28.0 230 28 15 5.9 3.2 | -2.2 28.0 235 26 13 5.8 3.2 15000 -1.4 29.5 230 28 14 5.9 3.2 | -1.3 29.7 235 26 13 5.8 3.2 14500 -0.6 30.9 230 28 14 5.9 3.2 | -0.5 31.1 235 26 13 5.9 3.2 14000 0.3 32.5 230 27 14 5.8 3.2 | 0.4 32.7 235 25 13 6.0 3.3 13500 1.1 34.0 225 27 14 5.9 3.2 | 1.2 34.2 235 25 13 6.0 3.3 13000 1.9 35.4 225 26 13 6.0 3.3 | 2.1 35.8 235 25 13 5.9 3.2 12500 2.8 37.0 220 25 13 5.9 3.3 | 2.9 37.2 230 25 13 5.9 3.3 12000 3.6 38.5 215 24 12 5.6 3.1 | 3.7 38.7 230 24 12 6.1 3.4 11500 4.4 39.9 215 23 12 5.6 3.1 | 4.6 40.3 230 23 12 6.1 3.4 11000 5.2 41.4 210 21 11 5.8 3.2 | 5.4 41.7 225 23 12 5.9 3.3 10500 6.0 42.8 210 20 10 5.8 3.2 | 6.3 43.3 220 22 11 5.9 3.2 10250 6.5 43.7 210 20 10 6.4 3.5 | 6.7 44.1 220 21 11 5.3 2.9 10000 6.9 44.4 205 19 10 6.7 3.7 | 7.1 44.8 220 20 10 5.9 3.2 9750 7.4 45.3 205 19 10 6.6 3.6 | 7.5 45.5 215 19 10 6.5 3.6 9500 7.9 46.2 200 18 9 6.8 3.7 | 7.9 46.2 210 18 9 6.5 3.5 9250 8.4 47.1 200 18 9 8.0 4.4 | 9.1 48.4 205 17 9 7.3 4.0 9000 9.0 48.2 195 17 9 7.1 3.9 | 9.5 49.1 200 16 8 4.8 2.6 8750 9.8 49.6 190 16 8 5.8 3.2 | 9.9 49.8 195 15 8 6.0 3.3 8500 10.2 50.4 185 16 8 6.1 3.3 | 10.3 50.5 195 14 7 7.3 4.0 8250 10.7 51.3 180 16 8 5.8 3.2 | 10.9 51.6 190 13 7 7.3 4.0 8000 11.1 52.0 180 15 8 4.6 2.5 | 11.4 52.5 185 12 6 6.2 3.4 7750 11.4 52.5 175 14 7 4.5 2.5 | 11.8 53.2 180 11 6 6.4 3.5 7500 11.7 53.1 170 14 7 5.0 2.7 | 12.3 54.1 180 10 5 6.9 3.8 7250 12.1 53.8 165 14 7 4.8 2.7 | 12.8 55.0 175 10 5 6.8 3.7 7000 12.4 54.3 160 14 7 3.5 1.9 | 13.3 55.9 175 9 5 8.2 4.5 6750 12.6 54.7 160 11 6 3.3 1.8 | 14.0 57.2 175 8 4 9.1 5.0 6500 12.9 55.2 155 10 5 4.2 2.3 | 14.6 58.3 170 7 4 9.1 5.0 6250 13.2 55.8 150 8 4 3.8 2.1 | 15.3 59.5 170 7 4 8.4 4.6 6000 13.4 56.1 145 9 5 3.9 2.1 | 15.9 60.6 170 6 3 11.0 6.0 5750 13.7 56.7 135 7 3 4.5 2.5 | 17.0 62.6 170 5 3 17.9 9.8 5500 14.0 57.2 115 4 2 3.3 1.8 | 18.0 64.4 160 5 3 6.2 3.4 5250 M M M M M M M | M M M M M M M 5000 M M M M M M M | M M M M M M M 10/10/2025 at 1500 MDT | 10/10/2025 at 1800 MDT | CAPE... +312.5 LI... -1.5 | CAPE... +288.1 LI... -1.0 CINH... -10.5 K Index... +29.0 | CINH... -14.5 K Index... +28.6 | 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 -67.5 -89.5 250 54 28 4.4 2.4 | -67.4 -89.3 250 51 26 4.3 2.3 45000 -59.4 -74.9 255 76 39 6.6 3.6 | -60.0 -76.0 255 72 37 6.7 3.7 40000 -49.9 -57.8 245 82 42 4.4 2.4 | -49.8 -57.6 245 84 43 4.7 2.6 38000 -47.3 -53.1 240 74 38 4.3 2.4 | -47.0 -52.6 245 73 38 4.7 2.6 36000 -44.7 -48.5 235 67 34 3.9 2.1 | -44.2 -47.6 235 64 33 4.4 2.4 34000 -40.1 -40.2 230 59 30 8.3 4.6 | -39.9 -39.8 235 55 28 7.6 4.2 32000 -35.1 -31.2 225 51 26 8.1 4.5 | -35.3 -31.5 235 47 24 7.4 4.1 30000 -30.2 -22.4 220 47 24 8.1 4.4 | -30.5 -22.9 235 42 22 8.2 4.5 29000 -27.8 -18.0 220 46 24 8.1 4.5 | -28.1 -18.6 230 41 21 8.2 4.5 28000 -25.4 -13.7 225 44 23 7.8 4.3 | -25.6 -14.1 230 39 20 8.0 4.4 27000 -23.4 -10.1 225 40 21 6.7 3.7 | -23.6 -10.5 230 36 19 6.8 3.8 26000 -20.9 -5.6 225 34 18 6.8 3.7 | -21.0 -5.8 230 32 17 6.9 3.8 25000 -18.9 -2.0 230 30 15 6.7 3.7 | -19.0 -2.2 230 30 15 6.9 3.8 24000 -17.0 1.4 225 27 14 6.5 3.6 | -17.0 1.4 230 27 14 6.7 3.7 23000 -15.0 5.0 225 24 13 6.5 3.6 | -15.1 4.8 230 24 13 6.8 3.7 22000 -13.1 8.4 220 22 11 6.4 3.5 | -13.1 8.4 225 22 11 6.6 3.6 21000 -11.4 11.5 225 21 11 6.1 3.3 | -11.3 11.7 225 21 11 6.2 3.4 20000 -9.6 14.7 225 20 10 6.1 3.4 | -9.5 14.9 225 20 10 6.2 3.4 19500 -8.7 16.3 230 20 10 6.2 3.4 | -8.6 16.5 225 20 10 6.2 3.4 19000 -7.9 17.8 230 20 10 5.4 3.0 | -7.7 18.1 220 20 10 5.7 3.1 18500 -7.1 19.2 230 20 10 5.4 3.0 | -6.9 19.6 220 19 10 5.7 3.1 18000 -6.3 20.7 235 20 10 5.3 2.9 | -6.1 21.0 220 19 10 5.6 3.1 17500 -5.5 22.1 235 21 11 5.0 2.8 | -5.3 22.5 220 19 10 5.3 2.9 17000 -4.8 23.4 235 21 11 5.0 2.7 | -4.6 23.7 225 19 10 5.3 2.9 16500 -4.1 24.6 235 21 11 5.4 2.9 | -3.8 25.2 225 19 10 5.3 2.9 16000 -3.3 26.1 235 21 11 5.3 2.9 | -3.1 26.4 225 19 10 5.3 2.9 15500 -2.5 27.5 235 22 11 5.3 2.9 | -2.3 27.9 225 18 9 5.2 2.8 15000 -1.8 28.8 235 21 11 5.4 2.9 | -1.6 29.1 225 18 9 5.1 2.8 14500 -1.0 30.2 230 21 11 5.5 3.0 | -0.8 30.6 225 18 9 5.1 2.8 14000 -0.2 31.6 230 21 11 5.8 3.2 | -0.1 31.8 225 18 9 5.1 2.8 13500 0.7 33.3 230 21 11 5.9 3.2 | 0.6 33.1 225 18 9 5.1 2.8 13000 1.5 34.7 225 21 11 6.4 3.5 | 1.4 34.5 220 18 9 6.3 3.5 12500 2.4 36.3 225 20 10 6.4 3.5 | 2.3 36.1 220 17 9 6.2 3.4 12000 3.4 38.1 220 20 10 7.1 3.9 | 3.2 37.8 220 17 9 6.2 3.4 11500 4.4 39.9 220 19 10 7.1 3.9 | 4.1 39.4 220 16 8 6.1 3.4 11000 5.4 41.7 215 18 9 7.0 3.8 | 5.0 41.0 215 16 8 6.7 3.7 10500 6.4 43.5 210 17 9 6.9 3.8 | 6.0 42.8 215 15 8 7.0 3.8 10250 6.8 44.2 210 17 9 4.8 2.6 | 6.5 43.7 215 15 8 5.7 3.1 10000 7.1 44.8 210 16 8 5.6 3.0 | 6.8 44.2 215 15 7 5.8 3.2 9750 7.6 45.7 205 16 8 7.5 4.1 | 7.3 45.1 210 14 7 7.2 3.9 9500 8.1 46.6 205 15 8 6.9 3.8 | 7.8 46.0 210 14 7 6.8 3.7 9250 8.6 47.5 200 15 8 6.6 3.6 | 8.3 46.9 205 13 7 7.3 4.0 9000 9.0 48.2 200 14 7 6.1 3.4 | 9.2 48.6 205 12 6 6.0 3.3 8750 9.4 48.9 195 13 7 6.1 3.3 | 9.6 49.3 200 11 6 6.2 3.4 8500 10.3 50.5 190 12 6 5.9 3.2 | 10.1 50.2 200 10 5 6.4 3.5 8250 10.7 51.3 185 11 6 6.1 3.3 | 10.5 50.9 195 10 5 6.5 3.5 8000 11.2 52.2 185 10 5 7.1 3.9 | 10.9 51.6 190 9 4 6.2 3.4 7750 11.7 53.1 180 9 5 6.5 3.6 | 11.4 52.5 185 8 4 5.9 3.2 7500 12.1 53.8 180 9 4 5.4 3.0 | 11.8 53.2 185 7 4 5.5 3.0 7250 12.5 54.5 175 8 4 5.8 3.2 | 12.2 54.0 180 7 4 5.5 3.0 7000 13.0 55.4 170 7 4 9.1 5.0 | 12.5 54.5 175 6 3 6.1 3.4 6750 13.8 56.8 170 6 3 9.3 5.1 | 13.0 55.4 165 5 3 6.3 3.5 6500 14.3 57.7 165 5 3 7.2 4.0 | 13.4 56.1 155 5 2 6.0 3.3 6250 14.9 58.8 160 5 2 7.8 4.3 | 13.9 57.0 150 4 2 5.9 3.2 6000 15.5 59.9 155 4 2 11.4 6.2 | 14.3 57.7 140 4 2 7.7 4.2 5750 16.5 61.7 155 3 2 16.8 9.2 | 14.9 58.8 130 3 1 10.8 5.9 5500 17.4 63.3 140 3 1 1.1 0.6 | 15.5 59.9 110 2 1 0.4 0.2 5250 M M M M M M M | M M M M M M M 5000 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) and again by approximately 1830 MST/1930 MDT (0130 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 at Walker Field in Grand Junction, Colorado at North Latitude: 39 deg 07 min 00.001 sec West Longitude: 108 deg 31 min 59.998 sec Elevation: 4839 feet (1475 meters) and may not be representative of other areas along the Western Slope of Colorado. 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. CINH (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