Soaring Guidance
Issued by NWS Denver/Boulder, CO
Issued by NWS Denver/Boulder, CO
936 UXUS97 KBOU 161332 SRGBOU Soaring Forecast National Weather Service Denver/Boulder, Colorado 0722 MDT Tuesday, July 16, 2024 This forecast is for Tuesday, July 16, 2024: If the trigger temperature of 84.0 F/28.9 C is reached...then Thermal Soaring Index....................... Excellent Maximum rate of lift........................ 1244 ft/min (6.3 m/s) Maximum height of thermals.................. 16532 ft MSL (11224 ft AGL) Forecast maximum temperature................... 90.0 F/32.7 C Time of trigger temperature.................... 1030 MDT Time of overdevelopment........................ 1500 MDT Middle/high clouds during soaring window....... None Surface winds during soaring window............ 20 mph or less Height of the -3 thermal index................. 10280 ft MSL (4972 ft AGL) Thermal soaring outlook for Wednesday 07/17.... Good Wave Soaring Index............................. Poor Wave Soaring Index trend (to 1800 MDT)......... No change Height of stable layer (12-18K ft MSL)......... None Weak PVA/NVA (through 1800 MDT)................ Weak PVA Potential height of wave....................... 26766 ft MSL (21458 ft AGL) Wave soaring outlook for Wednesday 07/17....... Poor Remarks... Sunrise/Sunset.................... 05:45:28 / 20:25:50 MDT Total possible sunshine........... 14 hr 40 min 22 sec (880 min 22 sec) Altitude of sun at 13:05:39 MDT... 71.37 degrees Upper air data from numerical model forecast valid on 07/16/2024 at 0600 MDT Freezing level.................. 15943 ft MSL (10635 ft AGL) Convective condensation level... 15534 ft MSL (10226 ft AGL) Lifted condensation level....... 15871 ft MSL (10563 ft AGL) Lifted index.................... -3.3 K index......................... +27.2 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 -62.1 -79.8 300 14 7 2.0 1.1 M M M M M 45000 -57.5 -71.5 290 18 9 5.0 2.7 M M M M M 40000 -49.9 -57.8 275 21 11 5.9 3.2 M M M M M 38000 -46.3 -51.3 265 27 14 5.9 3.2 M M M M M 36000 -42.3 -44.1 255 36 18 6.7 3.7 M M M M M 34000 -37.8 -36.0 260 34 18 7.5 4.1 M M M M M 32000 -33.4 -28.1 260 33 17 7.8 4.3 M M M M M 30000 -29.3 -20.7 265 30 16 6.8 3.7 46.8 116.2 11.0 M M 29000 -27.2 -17.0 265 29 15 6.8 3.8 45.7 114.2 10.3 M M 28000 -25.2 -13.4 270 28 14 6.8 3.7 44.7 112.4 9.6 M M 27000 -23.2 -9.8 270 28 14 6.8 3.7 43.4 110.2 8.7 M M 26000 -21.2 -6.2 275 28 14 6.9 3.8 42.3 108.2 7.9 M M 25000 -19.2 -2.6 280 28 14 6.8 3.7 41.4 106.4 7.1 M M 24000 -17.2 1.0 280 27 14 6.6 3.6 40.1 104.2 6.1 M M 23000 -15.3 4.5 280 27 14 6.6 3.6 39.0 102.1 5.2 M M 22000 -13.4 7.9 280 26 14 6.8 3.7 37.9 100.3 4.4 M M 21000 -11.3 11.7 280 25 13 7.0 3.9 36.9 98.3 3.5 M M 20000 -9.2 15.4 280 23 12 7.1 3.9 35.9 96.6 2.6 M M 19500 -8.2 17.2 285 22 12 7.0 3.9 35.5 95.9 2.2 M M 19000 -7.2 19.0 285 21 11 7.3 4.0 35.0 95.1 1.9 M M 18500 -5.6 21.9 290 20 10 7.2 4.0 34.4 93.9 1.3 M M 18000 -4.5 23.9 290 19 10 7.7 4.2 34.0 93.2 0.9 M M 17500 -3.3 26.1 290 18 9 7.7 4.2 33.6 92.6 0.6 M M 17000 -2.2 28.0 295 17 9 7.8 4.3 33.3 92.0 0.2 M M 16500 -1.1 30.0 295 17 9 7.8 4.3 33.0 91.3 -0.1 1032 5.2 16000 0.1 32.2 300 17 9 7.8 4.3 32.7 90.8 -0.4 983 5.0 15500 1.3 34.3 300 16 8 8.2 4.5 32.4 90.3 -0.7 932 4.7 15000 2.5 36.5 300 16 8 8.2 4.5 32.1 89.8 -0.9 881 4.5 14500 3.7 38.7 305 16 8 8.6 4.7 31.9 89.4 -1.2 830 4.2 14000 5.0 41.0 305 16 8 8.7 4.8 31.7 89.1 -1.3 776 3.9 13500 6.3 43.3 305 16 8 8.9 4.9 31.5 88.8 -1.5 722 3.7 13000 7.6 45.7 305 16 8 9.0 5.0 31.4 88.6 -1.6 667 3.4 12500 9.0 48.2 305 16 8 9.0 5.0 31.3 88.4 -1.8 612 3.1 12000 10.3 50.5 305 16 8 9.0 4.9 31.2 88.2 -1.9 558 2.8 11500 11.6 52.9 305 16 8 8.8 4.9 31.1 88.0 -2.0 503 2.6 11000 12.9 55.2 305 16 8 8.2 4.5 30.9 87.6 -2.2 450 2.3 10500 14.2 57.6 305 16 8 3.3 1.8 30.7 87.3 -2.4 397 2.0 10250 14.2 57.6 305 15 8 4.7 2.6 30.0 86.0 -3.1 388 2.0 10000 15.0 59.0 305 15 8 12.1 6.7 30.1 86.2 -3.1 357 1.8 9750 15.8 60.4 305 15 8 10.8 5.9 30.2 86.3 -3.0 326 1.7 9500 16.6 61.9 305 15 8 8.6 4.7 30.3 86.5 -3.0 295 1.5 9250 17.0 62.6 305 15 8 4.9 2.7 30.0 85.9 -3.3 275 1.4 9000 17.4 63.3 300 14 7 6.9 3.8 29.7 85.4 -3.6 255 1.3 8750 18.0 64.4 300 14 7 8.9 4.9 29.5 85.1 -3.8 230 1.2 8500 18.6 65.5 300 13 7 6.2 3.4 29.4 84.9 -3.9 205 1.0 8250 18.9 66.0 300 12 6 3.6 2.0 29.0 84.2 -4.3 188 1.0 8000 19.2 66.6 300 12 6 4.4 2.4 28.5 83.4 -4.8 173 0.9 7750 19.5 67.1 295 11 5 5.2 2.9 28.2 82.7 -5.2 155 0.8 7500 19.8 67.6 290 9 5 3.3 1.8 27.8 82.0 -5.7 139 0.7 7250 19.9 67.8 290 9 5 1.7 0.9 27.2 80.9 -6.3 128 0.6 7000 20.1 68.2 285 8 4 2.0 1.1 26.6 79.8 -6.9 117 0.6 6750 20.1 68.2 280 7 4 1.3 0.7 26.0 78.7 -7.6 107 0.5 6500 20.2 68.4 260 5 3 1.3 0.7 25.3 77.6 -8.3 99 0.5 6250 20.2 68.4 245 5 3 0.8 0.4 24.7 76.4 -9.0 89 0.5 6000 20.3 68.5 230 5 3 3.3 1.8 24.0 75.2 -9.7 80 0.4 5750 20.4 68.7 215 6 3 -3.9 -2.1 23.5 74.2 -10.3 69 0.4 5500 19.3 66.7 205 5 3 -23.2 -12.8 21.7 71.0 -12.2 95 0.5 * * * * * * Numerical weather prediction model forecast data valid * * * * * * 07/16/2024 at 0900 MDT | 07/16/2024 at 1200 MDT | CAPE... +236.4 LI... -1.8 | CAPE... +362.1 LI... -2.1 CINH... -128.6 K Index... +28.0 | CINH... -17.2 K Index... +30.6 | 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 -62.2 -80.0 300 15 8 1.9 1.0 | -62.1 -79.8 305 14 7 1.5 0.8 45000 -57.5 -71.5 290 21 11 5.2 2.9 | -57.9 -72.2 295 22 11 5.4 3.0 40000 -49.5 -57.1 275 21 11 6.0 3.3 | -49.2 -56.6 275 25 13 6.0 3.3 38000 -45.8 -50.4 270 26 14 6.0 3.3 | -45.6 -50.1 270 30 15 6.0 3.3 36000 -41.8 -43.2 265 32 16 6.4 3.5 | -42.0 -43.6 270 35 18 6.1 3.4 34000 -37.7 -35.9 265 36 19 6.8 3.7 | -38.1 -36.6 265 39 20 6.5 3.6 32000 -33.6 -28.5 260 40 21 7.1 3.9 | -34.2 -29.6 260 42 22 6.3 3.4 30000 -29.4 -20.9 265 37 19 7.0 3.9 | -29.8 -21.6 265 40 21 7.6 4.2 29000 -27.3 -17.1 265 35 18 7.0 3.9 | -27.5 -17.5 265 38 20 7.6 4.2 28000 -25.3 -13.5 270 33 17 6.7 3.7 | -24.7 -12.5 270 36 19 6.4 3.5 27000 -23.3 -9.9 270 32 16 6.7 3.7 | -22.8 -9.0 270 34 18 6.6 3.6 26000 -21.3 -6.3 270 30 15 6.7 3.7 | -20.9 -5.6 270 33 17 6.6 3.6 25000 -19.3 -2.7 275 28 15 6.7 3.7 | -18.9 -2.0 270 31 16 6.6 3.6 24000 -17.4 0.7 275 28 14 6.4 3.5 | -17.0 1.4 270 30 15 6.5 3.6 23000 -15.5 4.1 275 27 14 6.4 3.5 | -15.1 4.8 275 29 15 6.5 3.6 22000 -13.6 7.5 275 26 13 6.6 3.6 | -13.2 8.2 280 28 14 6.8 3.7 21000 -11.6 11.1 275 26 13 6.9 3.8 | -11.2 11.8 280 28 14 7.0 3.8 20000 -9.6 14.7 275 25 13 6.9 3.8 | -9.1 15.6 285 27 14 7.0 3.8 19500 -8.6 16.5 275 25 13 7.0 3.8 | -8.1 17.4 285 27 14 7.0 3.8 19000 -7.6 18.3 275 24 13 7.1 3.9 | -7.1 19.2 285 26 13 7.0 3.8 18500 -6.1 21.0 275 23 12 7.1 3.9 | -6.1 21.0 285 25 13 7.0 3.8 18000 -5.0 23.0 280 22 11 7.4 4.1 | -5.1 22.8 285 25 13 7.0 3.8 17500 -4.0 24.8 280 20 10 7.5 4.1 | -4.2 24.4 285 24 12 7.0 3.8 17000 -2.9 26.8 280 19 10 7.8 4.3 | -3.2 26.2 285 23 12 7.0 3.8 16500 -1.7 28.9 285 18 9 8.1 4.4 | -2.2 28.0 285 22 11 7.2 3.9 16000 -0.5 31.1 285 17 9 8.2 4.5 | -1.1 30.0 285 21 11 7.1 3.9 15500 0.7 33.3 285 16 8 8.5 4.6 | -0.1 31.8 290 20 10 7.6 4.2 15000 2.0 35.6 290 15 8 8.4 4.6 | 1.6 34.9 290 18 9 7.6 4.2 14500 3.2 37.8 290 14 7 8.5 4.7 | 2.7 36.9 295 17 9 8.4 4.6 14000 4.5 40.1 295 14 7 8.5 4.7 | 3.9 39.0 300 16 8 8.3 4.6 13500 5.7 42.3 295 13 7 8.4 4.6 | 5.1 41.2 300 15 8 8.0 4.4 13000 7.0 44.6 300 13 7 8.3 4.6 | 6.3 43.3 305 13 7 7.9 4.4 12500 8.2 46.8 305 13 6 8.3 4.6 | 7.4 45.3 315 12 6 8.3 4.6 12000 9.4 48.9 310 12 6 8.3 4.6 | 8.7 47.7 320 10 5 8.5 4.7 11500 10.6 51.1 315 12 6 8.0 4.4 | 9.9 49.8 325 10 5 8.4 4.6 11000 11.8 53.2 320 12 6 7.3 4.0 | 11.2 52.2 335 9 5 8.0 4.4 10500 12.9 55.2 325 12 6 3.2 1.7 | 12.4 54.3 340 9 5 3.0 1.7 10250 12.9 55.2 330 11 6 4.1 2.3 | 12.5 54.5 345 9 4 4.8 2.7 10000 13.6 56.5 330 12 6 10.5 5.8 | 13.3 55.9 350 8 4 12.7 7.0 9750 14.3 57.7 335 12 6 9.9 5.5 | 14.1 57.4 355 8 4 11.5 6.3 9500 15.0 59.0 335 12 6 7.3 4.0 | 14.9 58.8 360 8 4 8.2 4.5 9250 15.4 59.7 340 11 6 4.0 2.2 | 15.3 59.5 005 8 4 5.7 3.1 9000 15.7 60.3 340 11 6 6.9 3.8 | 15.9 60.6 010 7 4 10.2 5.6 8750 16.3 61.3 345 11 6 8.8 4.8 | 16.7 62.1 015 7 4 11.5 6.3 8500 16.9 62.4 345 11 6 6.2 3.4 | 17.5 63.5 020 7 4 9.3 5.1 8250 17.2 63.0 350 11 5 4.0 2.2 | 18.0 64.4 020 7 4 6.8 3.8 8000 17.6 63.7 350 10 5 5.4 3.0 | 18.6 65.5 025 7 4 10.4 5.7 7750 18.0 64.4 355 10 5 6.5 3.6 | 19.5 67.1 025 7 4 12.8 7.0 7500 18.4 65.1 355 9 5 5.9 3.2 | 20.4 68.7 025 7 4 9.3 5.1 7250 18.8 65.8 360 9 4 5.0 2.7 | 21.0 69.8 025 7 4 7.1 3.9 7000 19.2 66.6 360 8 4 6.5 3.6 | 21.6 70.9 025 7 4 10.3 5.7 6750 19.8 67.6 005 7 4 9.3 5.1 | 22.5 72.5 030 7 4 13.6 7.4 6500 20.4 68.7 005 6 3 8.5 4.7 | 23.4 74.1 030 7 4 11.4 6.3 6250 21.0 69.8 010 5 3 8.4 4.6 | 24.2 75.6 030 7 4 10.9 6.0 6000 21.5 70.7 015 4 2 5.3 2.9 | 25.0 77.0 030 7 3 9.1 5.0 5750 21.8 71.2 020 4 2 8.9 4.9 | 25.8 78.4 030 7 4 16.2 8.9 5500 23.1 73.6 020 4 2 25.0 13.7 | 27.7 81.9 030 7 3 34.1 18.7 07/16/2024 at 1500 MDT | 07/16/2024 at 1800 MDT | CAPE... +368.9 LI... -2.5 | CAPE... +296.8 LI... -2.0 CINH... -18.1 K Index... +31.8 | CINH... -26.1 K Index... +30.6 | 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 -62.4 -80.3 290 15 8 1.7 1.0 | -62.5 -80.5 300 17 9 1.9 1.1 45000 -57.9 -72.2 290 22 11 5.5 3.0 | -57.9 -72.2 290 25 13 5.4 2.9 40000 -49.3 -56.7 270 26 13 5.4 2.9 | -49.4 -56.9 260 32 16 5.5 3.0 38000 -46.1 -51.0 260 33 17 5.4 2.9 | -46.2 -51.2 255 36 18 5.5 3.0 36000 -42.8 -45.0 260 40 20 5.9 3.2 | -42.9 -45.2 250 40 21 5.9 3.2 34000 -38.4 -37.1 255 41 21 7.5 4.1 | -38.4 -37.1 250 39 20 7.5 4.1 32000 -33.9 -29.0 250 42 22 7.3 4.0 | -33.9 -29.0 255 37 19 7.3 4.0 30000 -28.7 -19.7 255 39 20 7.8 4.3 | -28.9 -20.0 260 34 17 7.6 4.1 29000 -26.4 -15.5 255 38 20 7.8 4.3 | -26.6 -15.9 265 33 17 7.6 4.2 28000 -24.2 -11.6 260 37 19 6.9 3.8 | -24.4 -11.9 270 32 16 6.8 3.8 27000 -22.1 -7.8 265 35 18 7.0 3.8 | -22.4 -8.3 275 31 16 6.9 3.8 26000 -20.1 -4.2 270 33 17 7.0 3.8 | -20.3 -4.5 280 31 16 6.9 3.8 25000 -18.0 -0.4 275 32 17 6.5 3.6 | -18.3 -0.9 290 31 16 6.7 3.7 24000 -16.2 2.8 280 32 16 6.1 3.3 | -16.4 2.5 295 29 15 6.3 3.4 23000 -14.4 6.1 280 32 16 6.1 3.3 | -14.6 5.7 295 27 14 6.3 3.4 22000 -12.6 9.3 285 32 16 6.2 3.4 | -12.7 9.1 300 26 13 6.4 3.5 21000 -10.8 12.6 290 31 16 6.3 3.5 | -10.9 12.4 305 24 12 6.6 3.6 20000 -9.0 15.8 290 30 15 6.3 3.5 | -9.0 15.8 310 22 11 6.6 3.6 19500 -8.0 17.6 295 30 15 6.4 3.5 | -8.0 17.6 315 21 11 6.6 3.6 19000 -7.1 19.2 295 29 15 7.1 3.9 | -7.1 19.2 315 20 10 7.0 3.8 18500 -6.1 21.0 295 28 15 7.1 3.9 | -6.1 21.0 315 19 10 7.0 3.8 18000 -5.0 23.0 295 27 14 7.6 4.1 | -5.1 22.8 320 19 10 7.1 3.9 17500 -3.9 25.0 300 26 14 7.8 4.3 | -4.0 24.8 320 18 9 7.2 3.9 17000 -2.8 27.0 300 25 13 7.9 4.3 | -2.5 27.5 325 17 9 7.4 4.1 16500 -1.7 28.9 300 23 12 7.5 4.1 | -1.4 29.5 330 16 8 7.5 4.1 16000 -0.1 31.8 305 20 10 7.5 4.1 | -0.3 31.5 330 15 8 7.6 4.2 15500 0.9 33.6 310 17 9 7.6 4.1 | 0.8 33.4 335 14 7 7.6 4.2 15000 2.0 35.6 315 15 7 7.5 4.1 | 1.9 35.4 340 13 7 7.6 4.2 14500 3.1 37.6 320 12 6 8.1 4.5 | 3.0 37.4 340 12 6 7.6 4.2 14000 4.3 39.7 325 10 5 8.1 4.4 | 4.1 39.4 345 11 6 7.6 4.2 13500 5.5 41.9 335 8 4 8.1 4.5 | 5.2 41.4 345 10 5 8.1 4.5 13000 6.7 44.1 340 7 4 8.2 4.5 | 6.4 43.5 350 9 5 8.3 4.6 12500 7.9 46.2 350 7 3 8.7 4.8 | 7.6 45.7 350 9 4 8.5 4.7 12000 9.2 48.6 355 6 3 9.0 5.0 | 8.9 48.0 350 8 4 8.7 4.8 11500 10.5 50.9 005 6 3 9.2 5.0 | 10.2 50.4 350 8 4 8.6 4.7 11000 11.9 53.4 005 6 3 9.0 5.0 | 11.5 52.7 355 7 4 8.3 4.6 10500 13.3 55.9 010 5 3 4.5 2.5 | 12.7 54.9 355 7 3 3.8 2.1 10250 13.5 56.3 015 5 3 6.1 3.4 | 12.8 55.0 350 7 3 5.2 2.9 10000 14.3 57.7 015 5 3 13.2 7.3 | 13.6 56.5 355 6 3 12.3 6.7 9750 15.2 59.4 015 5 3 12.1 6.7 | 14.4 57.9 355 6 3 11.0 6.1 9500 16.1 61.0 015 5 2 9.4 5.2 | 15.2 59.4 355 5 3 8.9 4.9 9250 16.6 61.9 020 5 2 7.3 4.0 | 15.8 60.4 360 5 3 6.8 3.7 9000 17.3 63.1 020 5 2 10.6 5.8 | 16.4 61.5 360 5 2 9.5 5.2 8750 18.1 64.6 020 4 2 11.5 6.3 | 17.1 62.8 360 4 2 10.7 5.8 8500 18.9 66.0 020 4 2 9.7 5.3 | 17.9 64.2 355 3 1 9.2 5.0 8250 19.6 67.3 025 4 2 7.8 4.3 | 18.5 65.3 005 3 1 7.8 4.3 8000 20.2 68.4 025 4 2 9.9 5.4 | 19.1 66.4 015 3 1 9.0 4.9 7750 21.0 69.8 025 4 2 11.3 6.2 | 19.8 67.6 005 2 1 9.8 5.4 7500 21.8 71.2 025 4 2 9.3 5.1 | 20.5 68.9 335 1 0 8.9 4.9 7250 22.4 72.3 030 4 2 7.8 4.3 | 21.1 70.0 360 1 0 8.1 4.4 7000 23.0 73.4 030 3 2 9.8 5.4 | 21.7 71.1 020 1 0 8.9 4.9 6750 23.9 75.0 030 3 2 12.1 6.6 | 22.4 72.3 000 0 0 10.1 5.5 6500 24.7 76.5 030 3 2 10.6 5.8 | 23.2 73.8 230 1 1 9.6 5.3 6250 25.5 77.9 035 3 2 9.7 5.3 | 23.8 74.8 235 1 1 9.5 5.2 6000 26.2 79.2 040 3 1 9.2 5.1 | 24.5 76.1 235 1 0 8.4 4.6 5750 27.0 80.6 035 3 1 15.0 8.2 | 25.1 77.2 230 2 1 11.1 6.1 5500 28.5 83.3 040 3 1 26.9 14.8 | 26.3 79.3 230 2 1 19.4 10.6 ________________________________________________________________________________ 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 near the old Stapleton Airport site in Denver, Colorado at North Latitude: 39 deg 46 min 5.016 sec West Longitude: 104 deg 52 min 9.984 sec Elevation: 5285 feet (1611 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. 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