Soaring Guidance
Issued by NWS Grand Junction, CO
Issued by NWS Grand Junction, CO
029 UXUS97 KGJT 081306 SRGGJT Soaring Forecast National Weather Service Grand Junction, Colorado 706 AM MDT Tuesday, July 8, 2025 This forecast is for Tuesday, July 8, 2025: If the trigger temperature of 87.7 F/31.0 C is reached...then Thermal Soaring Index....................... Excellent Maximum rate of lift........................ 1675 ft/min (8.5 m/s) Maximum height of thermals.................. 22777 ft MSL (17168 ft AGL) Forecast maximum temperature................... 100.0 F/38.2 C Time of trigger temperature.................... 1030 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................. 19560 ft MSL (13951 ft AGL) Thermal soaring outlook for Wednesday 07/09.... Excellent Wave Soaring Index............................. Not available Remarks... Sunrise/Sunset.................... 05:56:10 / 20:42:31 MDT Total possible sunshine........... 14 hr 46 min 21 sec (886 min 21 sec) Altitude of sun at 13:19:20 MDT... 72.76 degrees Upper air data from rawinsonde observation taken on 07/08/2025 at 0600 MDT Freezing level.................. 16528 ft MSL (10919 ft AGL) Convective condensation level... 23529 ft MSL (17920 ft AGL) Lifted condensation level....... 23529 ft MSL (17920 ft AGL) Lifted index.................... +0.5 K index......................... +12.7 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 -65.3 -85.5 275 23 12 2.6 1.4 M M M M M 45000 -59.7 -75.5 280 38 20 5.8 3.2 M M M M M 40000 -50.8 -59.4 285 51 26 6.6 3.6 M M M M M 38000 -46.9 -52.4 285 52 27 6.6 3.6 M M M M M 36000 -42.4 -44.3 285 51 26 7.7 4.3 M M M M M 34000 -37.7 -35.9 285 46 24 7.8 4.3 M M M M M 32000 -33.0 -27.4 285 41 21 7.7 4.2 M M M M M 30000 -28.8 -19.8 285 37 19 6.9 3.8 46.0 114.8 6.3 M M 29000 -26.7 -16.1 285 35 18 6.9 3.8 45.0 113.0 5.6 M M 28000 -24.7 -12.5 285 33 17 6.7 3.7 43.9 111.1 4.8 M M 27000 -22.7 -8.9 285 31 16 6.7 3.7 42.7 108.8 3.9 M M 26000 -20.6 -5.1 285 29 15 6.7 3.7 41.6 106.8 3.0 M M 25000 -18.6 -1.5 285 27 14 6.6 3.6 40.6 105.0 2.3 M M 24000 -16.7 1.9 285 25 13 6.6 3.6 39.3 102.7 1.2 M M 23000 -14.7 5.5 280 23 12 6.6 3.6 38.2 100.7 0.3 M M 22000 -12.7 9.1 275 21 11 6.8 3.7 37.1 98.8 -0.6 1614 8.2 21000 -10.7 12.7 270 19 10 6.9 3.8 36.0 96.8 -1.6 1524 7.7 20000 -8.2 17.2 265 17 9 7.0 3.9 34.8 94.7 -2.7 1412 7.2 19500 -7.2 19.0 260 16 8 7.5 4.1 34.4 94.0 -3.1 1366 6.9 19000 -6.1 21.0 260 15 8 7.7 4.2 34.0 93.3 -3.5 1318 6.7 18500 -5.0 23.0 260 13 7 7.9 4.3 33.7 92.7 -3.9 1271 6.5 18000 -3.7 25.3 260 12 6 8.9 4.9 33.5 92.3 -4.2 1219 6.2 17500 -2.4 27.7 265 11 6 8.9 4.9 33.3 92.0 -4.3 1165 5.9 17000 -1.1 30.0 265 10 5 9.1 5.0 33.2 91.8 -4.5 1110 5.6 16500 0.2 32.4 270 9 5 9.1 5.0 33.1 91.5 -4.7 1055 5.4 16000 1.6 34.9 275 9 4 9.2 5.0 33.0 91.4 -4.8 1000 5.1 15500 3.0 37.4 280 9 4 9.2 5.1 32.9 91.2 -4.9 944 4.8 15000 4.3 39.7 290 9 4 9.2 5.1 32.8 91.1 -5.0 889 4.5 14500 5.7 42.3 295 9 5 9.5 5.2 32.7 90.9 -5.1 832 4.2 14000 7.1 44.8 295 9 5 9.4 5.2 32.7 90.9 -5.2 775 3.9 13500 8.5 47.3 300 9 5 9.6 5.2 32.7 90.8 -5.3 718 3.6 13000 10.0 50.0 300 9 5 9.6 5.3 32.6 90.7 -5.3 660 3.4 12500 11.4 52.5 300 9 5 9.2 5.0 32.6 90.7 -5.4 603 3.1 12000 12.7 54.9 300 9 4 9.1 5.0 32.5 90.4 -5.5 547 2.8 11500 14.1 57.4 300 8 4 8.6 4.7 32.4 90.2 -5.7 492 2.5 11000 15.4 59.7 300 8 4 8.1 4.5 32.1 89.8 -5.9 439 2.2 10500 16.8 62.2 295 7 3 9.3 5.1 32.1 89.7 -6.0 382 1.9 10250 17.4 63.3 295 6 3 7.4 4.1 31.9 89.5 -6.1 357 1.8 10000 18.0 64.4 295 5 3 7.9 4.3 31.8 89.2 -6.3 332 1.7 9750 18.6 65.5 295 5 2 7.8 4.3 31.6 88.9 -6.4 307 1.6 9500 19.1 66.4 295 4 2 6.7 3.7 31.5 88.6 -6.6 282 1.4 9250 19.6 67.3 295 3 2 7.0 3.8 31.2 88.1 -6.8 260 1.3 9000 20.2 68.4 280 2 1 8.1 4.4 31.0 87.9 -7.0 235 1.2 8750 20.8 69.4 260 2 1 7.7 4.2 30.9 87.6 -7.2 210 1.1 8500 21.4 70.5 225 1 1 6.6 3.6 30.7 87.3 -7.3 185 0.9 8250 21.8 71.2 180 2 1 5.5 3.0 30.4 86.7 -7.6 164 0.8 8000 22.2 72.0 170 3 1 5.7 3.1 30.1 86.1 -8.0 144 0.7 7750 22.6 72.7 165 4 2 5.0 2.8 29.8 85.6 -8.3 125 0.6 7500 22.9 73.2 160 4 2 3.2 1.7 29.3 84.8 -8.8 109 0.6 7250 23.1 73.6 155 5 3 1.9 1.0 28.8 83.8 -9.4 97 0.5 7000 23.2 73.8 150 6 3 2.5 1.4 28.2 82.7 -10.0 85 0.4 6750 23.3 73.9 150 6 3 -1.3 -0.7 27.6 81.6 -10.6 75 0.4 6500 23.0 73.4 140 6 3 -6.2 -3.4 26.5 79.6 -11.7 78 0.4 6250 22.5 72.5 130 6 3 -6.0 -3.3 25.3 77.5 -13.0 85 0.4 6000 22.1 71.8 120 6 3 -4.4 -2.4 24.1 75.4 -14.2 90 0.5 5750 21.4 70.5 115 6 3 -21.4 -11.8 22.7 72.8 -15.6 104 0.5 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 * * * * * * 07/08/2025 at 0900 MDT | 07/08/2025 at 1200 MDT | CAPE... +2.7 LI... +0.2 | CAPE... +58.5 LI... -0.1 CINH... -32.5 K Index... +18.5 | CINH... -18.1 K Index... +17.4 | 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 -64.6 -84.3 275 25 13 1.5 0.8 | -64.8 -84.6 270 25 13 1.7 0.9 45000 -59.6 -75.3 275 44 23 6.5 3.6 | -59.6 -75.3 280 44 23 6.4 3.5 40000 -49.8 -57.6 280 57 30 6.8 3.8 | -49.9 -57.8 285 53 27 6.7 3.7 38000 -45.7 -50.3 285 59 30 6.8 3.8 | -45.4 -49.7 285 57 29 6.7 3.7 36000 -41.1 -42.0 285 61 31 6.6 3.6 | -41.3 -42.3 285 59 31 6.7 3.7 34000 -37.3 -35.1 290 54 28 6.4 3.5 | -37.3 -35.1 290 55 28 6.6 3.6 32000 -33.4 -28.1 290 47 24 6.4 3.5 | -33.4 -28.1 290 51 26 6.6 3.6 30000 -29.9 -21.8 290 40 21 5.9 3.3 | -29.6 -21.3 290 45 23 6.2 3.4 29000 -28.1 -18.6 290 37 19 5.9 3.3 | -27.7 -17.9 290 41 21 6.2 3.4 28000 -26.3 -15.3 285 33 17 5.8 3.2 | -25.9 -14.6 290 38 20 5.6 3.1 27000 -24.6 -12.3 290 29 15 5.8 3.2 | -24.2 -11.6 290 34 17 5.7 3.1 26000 -22.9 -9.2 290 26 13 5.8 3.2 | -22.5 -8.5 295 29 15 5.7 3.1 25000 -21.1 -6.0 295 22 12 6.1 3.3 | -20.8 -5.4 295 25 13 5.9 3.2 24000 -19.2 -2.6 290 20 10 6.6 3.6 | -18.9 -2.0 295 21 11 6.4 3.5 23000 -17.2 1.0 290 17 9 6.7 3.7 | -16.6 2.1 285 16 8 6.4 3.5 22000 -14.7 5.5 280 14 7 7.4 4.0 | -14.6 5.7 280 13 7 7.5 4.1 21000 -12.6 9.3 275 12 6 7.4 4.1 | -12.5 9.5 270 12 6 7.5 4.1 20000 -10.5 13.1 265 11 6 7.5 4.1 | -10.3 13.5 255 11 6 7.6 4.2 19500 -9.3 15.3 260 11 5 8.6 4.7 | -9.2 15.4 250 11 6 8.6 4.7 19000 -8.0 17.6 260 11 5 9.0 4.9 | -7.9 17.8 250 11 6 8.9 4.9 18500 -6.7 19.9 260 11 5 9.1 5.0 | -6.6 20.1 250 11 6 9.0 4.9 18000 -5.3 22.5 255 10 5 9.6 5.3 | -5.2 22.6 245 11 6 9.6 5.2 17500 -3.9 25.0 255 10 5 9.5 5.2 | -3.8 25.2 245 11 6 9.5 5.2 17000 -2.5 27.5 255 10 5 9.6 5.3 | -2.4 27.7 245 11 6 9.5 5.2 16500 -1.1 30.0 255 10 5 9.6 5.3 | -1.0 30.2 250 11 6 9.5 5.2 16000 0.3 32.5 255 9 5 9.5 5.2 | 0.4 32.7 250 11 6 9.5 5.2 15500 1.7 35.1 255 9 5 9.3 5.1 | 1.8 35.2 250 10 5 9.5 5.2 15000 3.1 37.6 255 9 5 9.3 5.1 | 3.2 37.8 250 10 5 9.5 5.2 14500 4.5 40.1 255 9 4 9.3 5.1 | 4.6 40.3 250 10 5 9.3 5.1 14000 5.8 42.4 255 8 4 9.3 5.1 | 6.0 42.8 250 9 5 9.3 5.1 13500 7.2 45.0 255 8 4 9.0 5.0 | 7.4 45.3 250 9 5 9.3 5.1 13000 8.5 47.3 250 8 4 9.0 4.9 | 8.8 47.8 250 9 4 9.3 5.1 12500 9.8 49.6 250 8 4 8.8 4.8 | 10.2 50.4 250 8 4 9.2 5.1 12000 11.1 52.0 250 7 4 8.7 4.8 | 11.5 52.7 250 8 4 9.2 5.0 11500 12.4 54.3 250 7 4 8.4 4.6 | 12.9 55.2 255 7 4 9.0 4.9 11000 13.6 56.5 245 7 3 8.1 4.5 | 14.2 57.6 255 7 4 8.7 4.8 10500 14.9 58.8 245 6 3 7.2 3.9 | 15.5 59.9 255 6 3 7.4 4.1 10250 15.3 59.5 245 6 3 7.2 4.0 | 16.0 60.8 260 6 3 7.9 4.3 10000 16.0 60.8 240 6 3 8.5 4.6 | 16.7 62.1 260 6 3 9.7 5.3 9750 16.6 61.9 235 6 3 8.2 4.5 | 17.4 63.3 260 6 3 9.3 5.1 9500 17.2 63.0 235 6 3 8.0 4.4 | 18.1 64.6 260 5 3 8.8 4.8 9250 17.7 63.9 230 6 3 7.4 4.1 | 18.7 65.7 265 5 3 8.3 4.6 9000 18.3 64.9 225 6 3 6.5 3.6 | 19.3 66.7 270 5 3 8.9 4.9 8750 18.7 65.7 220 6 3 6.1 3.3 | 20.0 68.0 265 5 3 8.9 4.9 8500 19.2 66.6 210 6 3 5.8 3.2 | 20.6 69.1 265 5 2 7.6 4.2 8250 19.9 67.8 200 6 3 6.1 3.4 | 21.6 70.9 275 5 2 9.7 5.3 8000 20.4 68.7 195 6 3 6.7 3.7 | 22.5 72.5 270 4 2 12.6 6.9 7750 20.9 69.6 185 6 3 4.6 2.5 | 23.2 73.8 270 4 2 8.9 4.9 7500 21.1 70.0 180 7 3 3.0 1.6 | 23.8 74.8 275 4 2 6.8 3.7 7250 21.4 70.5 175 7 3 4.9 2.7 | 24.4 75.9 280 4 2 10.1 5.5 7000 21.9 71.4 170 6 3 7.8 4.3 | 25.3 77.5 275 4 2 13.0 7.2 6750 22.5 72.5 165 6 3 7.1 3.9 | 26.2 79.2 275 4 2 10.7 5.9 6500 22.9 73.2 160 5 3 6.4 3.5 | 26.9 80.4 280 4 2 9.6 5.3 6250 23.4 74.1 155 4 2 5.7 3.1 | 27.7 81.9 280 4 2 10.2 5.6 6000 23.9 75.0 150 6 3 10.7 5.9 | 28.6 83.5 275 4 2 17.5 9.6 5750 25.1 77.2 145 5 3 22.1 12.1 | 30.4 86.7 280 4 2 28.8 15.8 5500 26.4 79.5 140 5 2 0.9 0.5 | 32.1 89.8 290 4 2 9.0 4.9 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 07/08/2025 at 1500 MDT | 07/08/2025 at 1800 MDT | CAPE... +2.3 LI... +0.6 | CAPE... 0.0 LI... +1.0 CINH... -0.1 K Index... +14.1 | CINH... 0.0 K Index... +4.5 | 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 -65.3 -85.5 270 30 15 1.9 1.0 | -65.4 -85.7 275 31 16 1.7 0.9 45000 -59.9 -75.8 280 45 23 6.5 3.6 | -60.1 -76.2 280 47 24 6.7 3.7 40000 -50.1 -58.2 285 51 26 6.8 3.8 | -50.0 -58.0 285 54 28 6.9 3.8 38000 -45.4 -49.7 285 54 28 6.8 3.7 | -45.4 -49.7 290 53 27 6.9 3.8 36000 -41.3 -42.3 290 56 29 6.9 3.8 | -41.3 -42.3 290 52 27 6.9 3.8 34000 -37.2 -35.0 290 53 27 6.9 3.8 | -37.2 -35.0 290 50 26 6.9 3.8 32000 -33.1 -27.6 290 50 26 6.7 3.7 | -33.0 -27.4 290 48 25 6.7 3.7 30000 -29.4 -20.9 295 45 23 6.2 3.4 | -29.3 -20.7 290 43 22 6.2 3.4 29000 -27.5 -17.5 295 43 22 6.2 3.4 | -27.5 -17.5 290 41 21 6.2 3.4 28000 -25.7 -14.3 295 40 21 6.0 3.3 | -25.6 -14.1 290 38 20 6.5 3.6 27000 -23.8 -10.8 295 36 19 6.0 3.3 | -23.7 -10.7 295 34 18 6.5 3.5 26000 -22.0 -7.6 295 32 17 6.1 3.3 | -21.7 -7.1 295 30 15 6.5 3.6 25000 -20.2 -4.4 295 29 15 6.5 3.6 | -19.8 -3.6 295 26 13 6.9 3.8 24000 -17.6 0.3 295 22 12 7.0 3.9 | -17.1 1.2 295 21 11 7.2 4.0 23000 -15.5 4.1 290 18 9 7.0 3.9 | -15.0 5.0 295 17 9 7.2 4.0 22000 -13.4 7.9 285 14 7 7.6 4.2 | -12.7 9.1 290 14 7 8.2 4.5 21000 -11.2 11.8 275 11 6 7.7 4.2 | -10.3 13.5 280 11 6 8.1 4.5 20000 -8.9 16.0 255 9 5 7.7 4.2 | -7.9 17.8 265 9 5 8.1 4.5 19500 -7.8 18.0 250 9 5 8.5 4.7 | -6.7 19.9 255 8 4 8.3 4.5 19000 -6.5 20.3 245 9 5 8.7 4.8 | -5.5 22.1 255 9 4 8.3 4.6 18500 -5.2 22.6 245 9 5 8.7 4.8 | -4.3 24.3 250 9 5 8.4 4.6 18000 -4.0 24.8 245 9 5 8.7 4.8 | -3.0 26.6 250 9 5 8.9 4.9 17500 -2.7 27.1 245 9 5 8.7 4.8 | -1.7 28.9 250 9 5 8.9 4.9 17000 -1.4 29.5 245 9 5 9.1 5.0 | -0.4 31.3 255 10 5 9.0 4.9 16500 0.0 32.0 245 9 5 9.2 5.1 | 0.9 33.6 255 10 5 9.0 4.9 16000 1.4 34.5 250 9 5 9.3 5.1 | 2.3 36.1 260 10 5 9.2 5.0 15500 2.8 37.0 250 9 5 9.4 5.1 | 3.7 38.7 260 10 5 9.5 5.2 15000 4.2 39.6 250 9 5 9.4 5.1 | 5.1 41.2 260 10 5 9.5 5.2 14500 5.6 42.1 250 9 5 9.5 5.2 | 6.5 43.7 265 10 5 9.4 5.1 14000 7.0 44.6 255 9 5 9.5 5.2 | 7.9 46.2 265 10 5 9.4 5.1 13500 8.4 47.1 255 9 5 9.5 5.2 | 9.3 48.7 270 10 5 9.3 5.1 13000 9.8 49.6 255 9 5 9.5 5.2 | 10.7 51.3 270 10 5 9.3 5.1 12500 11.2 52.2 260 9 5 9.5 5.2 | 12.1 53.8 270 10 5 9.3 5.1 12000 12.7 54.9 260 9 5 9.6 5.3 | 13.5 56.3 275 11 5 9.4 5.1 11500 14.1 57.4 265 9 5 9.5 5.2 | 14.9 58.8 275 11 5 9.4 5.2 11000 15.5 59.9 265 10 5 9.3 5.1 | 16.3 61.3 275 11 5 9.3 5.1 10500 16.9 62.4 265 10 5 8.1 4.4 | 17.7 63.9 275 11 6 6.9 3.8 10250 17.5 63.5 270 10 5 8.7 4.7 | 18.2 64.8 275 11 6 7.5 4.1 10000 18.2 64.8 270 10 5 10.6 5.8 | 18.9 66.0 275 11 6 11.2 6.1 9750 19.0 66.2 270 10 5 10.1 5.5 | 19.7 67.5 275 11 6 10.5 5.8 9500 19.8 67.6 270 10 5 10.0 5.5 | 20.5 68.9 275 11 6 9.5 5.2 9250 20.5 68.9 275 10 5 9.6 5.3 | 21.1 70.0 280 11 6 8.6 4.7 9000 21.2 70.2 275 10 5 9.5 5.2 | 21.8 71.2 280 11 6 9.4 5.2 8750 21.9 71.4 275 10 5 9.5 5.2 | 22.5 72.5 280 11 6 9.6 5.3 8500 23.2 73.8 275 10 5 7.9 4.3 | 23.9 75.0 280 11 6 7.8 4.3 8250 23.9 75.0 280 11 5 10.3 5.7 | 24.5 76.1 280 11 6 10.1 5.5 8000 24.7 76.5 275 10 5 12.0 6.6 | 25.3 77.5 280 11 6 12.0 6.6 7750 25.6 78.1 275 10 5 9.6 5.3 | 26.1 79.0 280 11 6 9.5 5.2 7500 26.2 79.2 280 10 5 8.0 4.4 | 26.8 80.2 280 11 6 7.7 4.2 7250 26.8 80.2 280 11 6 10.1 5.5 | 27.4 81.3 280 11 6 9.5 5.2 7000 27.7 81.9 280 10 5 12.5 6.8 | 28.2 82.8 280 11 6 11.8 6.5 6750 28.6 83.5 280 10 5 11.1 6.1 | 29.1 84.4 280 10 5 10.7 5.9 6500 29.4 84.9 280 10 5 10.8 5.9 | 29.8 85.6 280 11 5 10.0 5.5 6250 30.2 86.4 280 10 5 8.8 4.8 | 30.6 87.1 280 11 5 9.0 4.9 6000 30.9 87.6 280 10 5 16.2 8.9 | 31.3 88.3 280 10 5 12.4 6.8 5750 32.9 91.2 280 9 5 35.5 19.5 | 32.6 90.7 280 9 5 23.1 12.7 5500 34.9 94.8 285 9 5 1.4 0.8 | 34.1 93.4 285 9 5 9.7 5.3 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