Soaring Guidance
Issued by NWS Denver/Boulder, CO
Issued by NWS Denver/Boulder, CO
740 UXUS97 KBOU 200022 SRGBOU Soaring Forecast National Weather Service Denver/Boulder, Colorado 1821 MDT Friday, July 19, 2024 This forecast is for Saturday, July 20, 2024: If the trigger temperature of 79.3 F/26.3 C is reached...then Thermal Soaring Index....................... Good Maximum rate of lift........................ 734 ft/min (3.7 m/s) Maximum height of thermals.................. 14001 ft MSL (8722 ft AGL) Forecast maximum temperature................... 86.0 F/30.5 C Time of trigger temperature.................... 1045 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................. 9985 ft MSL (4706 ft AGL) Thermal soaring outlook for Sunday 07/21....... 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)................ Neither Potential height of wave....................... 23748 ft MSL (18469 ft AGL) Wave soaring outlook for Sunday 07/21.......... Poor Remarks... Sunrise/Sunset.................... 05:48:42 / 20:23:08 MDT Total possible sunshine........... 14 hr 34 min 25 sec (874 min 25 sec) Altitude of sun at 13:05:55 MDT... 70.64 degrees Upper air data from numerical model forecast valid on 07/20/2024 at 0600 MDT Freezing level.................. 15640 ft MSL (10361 ft AGL) Convective condensation level... 13432 ft MSL (8153 ft AGL) Lifted condensation level....... 13644 ft MSL (8365 ft AGL) Lifted index.................... -4.4 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 -62.6 -80.7 330 36 19 2.2 1.2 M M M M M 45000 -56.5 -69.7 325 51 26 6.8 3.7 M M M M M 40000 -46.6 -51.9 320 55 28 5.5 3.0 M M M M M 38000 -43.3 -45.9 320 52 27 5.5 3.0 M M M M M 36000 -40.1 -40.2 320 48 25 5.4 3.0 M M M M M 34000 -37.4 -35.3 320 43 22 4.3 2.4 M M M M M 32000 -34.8 -30.6 320 39 20 4.0 2.2 M M M M M 30000 -30.4 -22.7 320 36 18 7.0 3.9 45.5 113.8 11.8 M M 29000 -28.2 -18.8 320 34 18 7.0 3.9 44.5 112.1 11.2 M M 28000 -26.1 -15.0 325 33 17 7.9 4.3 43.6 110.5 10.6 M M 27000 -23.7 -10.7 320 32 16 7.8 4.3 42.7 108.9 10.1 M M 26000 -21.4 -6.5 315 31 16 7.8 4.3 42.0 107.6 9.6 M M 25000 -19.1 -2.4 315 29 15 7.3 4.0 41.4 106.6 9.2 M M 24000 -17.1 1.2 320 27 14 6.8 3.7 40.2 104.4 8.3 M M 23000 -15.1 4.8 325 25 13 6.8 3.7 39.1 102.4 7.5 M M 22000 -13.0 8.6 335 23 12 6.6 3.6 38.2 100.7 6.7 M M 21000 -11.1 12.0 335 21 11 6.4 3.5 36.9 98.3 5.7 M M 20000 -9.2 15.4 335 20 10 6.4 3.5 35.7 96.2 4.8 M M 19500 -8.3 17.1 335 19 10 6.4 3.5 35.2 95.3 4.3 M M 19000 -7.3 18.9 335 18 9 6.6 3.6 34.6 94.3 3.8 M M 18500 -6.4 20.5 340 17 9 6.6 3.6 34.0 93.3 3.3 M M 18000 -5.4 22.3 340 17 8 7.2 3.9 33.5 92.4 2.9 M M 17500 -4.3 24.3 340 16 8 7.4 4.1 33.1 91.6 2.5 M M 17000 -3.2 26.2 340 16 8 7.5 4.1 32.7 90.9 2.1 M M 16500 -2.2 28.0 340 15 8 7.7 4.2 32.4 90.2 1.7 M M 16000 -1.1 30.0 340 15 7 7.7 4.2 32.0 89.6 1.4 M M 15500 0.0 32.0 345 14 7 8.0 4.4 31.7 89.0 1.0 M M 15000 1.7 35.1 350 13 7 8.1 4.4 31.3 88.3 0.5 M M 14500 2.9 37.2 355 13 7 8.3 4.6 31.0 87.8 0.2 M M 14000 4.1 39.4 350 13 6 8.4 4.6 30.8 87.4 -0.1 723 3.7 13500 5.3 41.5 350 12 6 8.4 4.6 30.5 87.0 -0.3 673 3.4 13000 6.5 43.7 345 12 6 8.5 4.7 30.3 86.6 -0.6 622 3.2 12500 7.7 45.9 345 13 6 8.1 4.5 30.1 86.2 -0.9 571 2.9 12000 8.8 47.8 340 13 6 8.0 4.4 29.8 85.7 -1.2 522 2.7 11500 10.0 50.0 340 13 6 7.8 4.3 29.6 85.2 -1.5 473 2.4 11000 11.1 52.0 345 12 6 7.7 4.2 29.2 84.6 -1.9 425 2.2 10500 12.1 53.8 345 12 6 3.9 2.2 28.8 83.9 -2.3 380 1.9 10250 12.3 54.1 345 12 6 4.6 2.5 28.3 82.9 -2.8 367 1.9 10000 12.8 55.0 345 12 6 9.7 5.3 28.1 82.6 -3.0 342 1.7 9750 13.5 56.3 345 12 6 9.3 5.1 28.1 82.6 -3.1 314 1.6 9500 14.1 57.4 350 12 6 5.7 3.1 28.0 82.4 -3.2 290 1.5 9250 14.4 57.9 350 12 6 3.0 1.7 27.5 81.5 -3.7 275 1.4 9000 14.6 58.3 350 13 6 6.1 3.3 27.1 80.7 -4.2 259 1.3 8750 15.1 59.2 355 13 7 7.2 4.0 26.9 80.4 -4.4 237 1.2 8500 15.5 59.9 355 13 7 4.9 2.7 26.6 79.9 -4.8 218 1.1 8250 15.8 60.4 355 13 7 4.1 2.3 26.2 79.1 -5.2 201 1.0 8000 16.1 61.0 350 13 7 4.9 2.7 25.8 78.4 -5.6 185 0.9 7750 16.5 61.7 350 13 7 3.7 2.0 25.4 77.7 -6.1 168 0.9 7500 16.6 61.9 350 12 6 1.9 1.1 24.8 76.7 -6.7 156 0.8 7250 16.7 62.1 345 12 6 1.6 0.9 24.2 75.6 -7.3 146 0.7 7000 16.8 62.2 340 11 6 2.6 1.4 23.6 74.5 -8.0 136 0.7 6750 16.9 62.4 335 11 6 2.9 1.6 23.1 73.6 -8.6 124 0.6 6500 17.0 62.6 325 10 5 2.2 1.2 22.5 72.6 -9.2 113 0.6 6250 17.2 63.0 315 10 5 2.4 1.3 22.0 71.6 -9.8 102 0.5 6000 17.3 63.1 305 10 5 2.2 1.2 21.4 70.6 -10.5 91 0.5 5750 17.4 63.3 305 8 4 2.2 1.2 20.9 69.5 -11.1 80 0.4 5500 17.6 63.7 300 6 3 2.7 1.5 20.3 68.5 -11.7 68 0.3 * * * * * * Numerical weather prediction model forecast data valid * * * * * * 07/20/2024 at 0900 MDT | 07/20/2024 at 1200 MDT | CAPE... +799.5 LI... -3.7 | CAPE... +1083.7 LI... -4.5 CINH... -121.5 K Index... +29.6 | CINH... -11.1 K Index... +27.3 | 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 -61.6 -78.9 330 35 18 2.1 1.2 | -61.0 -77.8 330 33 17 2.2 1.2 45000 -55.9 -68.6 320 49 25 6.3 3.4 | -55.3 -67.5 315 50 26 6.1 3.3 40000 -46.8 -52.2 315 57 30 5.1 2.8 | -46.6 -51.9 310 61 31 4.4 2.4 38000 -43.7 -46.7 315 53 28 5.1 2.8 | -43.9 -47.0 315 55 28 4.4 2.4 36000 -40.6 -41.1 315 50 26 5.1 2.8 | -41.3 -42.3 315 49 25 4.3 2.4 34000 -37.9 -36.2 315 43 22 4.4 2.4 | -38.4 -37.1 315 42 22 4.9 2.7 32000 -34.9 -30.8 315 36 18 5.0 2.7 | -35.1 -31.2 320 34 18 5.1 2.8 30000 -30.8 -23.4 320 31 16 7.1 3.9 | -31.2 -24.2 320 28 15 6.6 3.6 29000 -28.6 -19.5 325 29 15 7.1 3.9 | -29.3 -20.7 320 26 13 6.6 3.6 28000 -26.5 -15.7 325 27 14 7.0 3.8 | -27.2 -17.0 320 23 12 7.3 4.0 27000 -24.4 -11.9 325 25 13 7.0 3.8 | -25.1 -13.2 325 23 12 7.3 4.0 26000 -22.3 -8.1 325 24 12 7.0 3.9 | -22.9 -9.2 330 23 12 7.3 4.0 25000 -20.2 -4.4 320 23 12 6.8 3.7 | -20.7 -5.3 335 23 12 7.1 3.9 24000 -18.3 -0.9 325 23 12 6.5 3.6 | -18.7 -1.7 335 23 12 6.7 3.7 23000 -16.4 2.5 325 22 12 6.6 3.6 | -16.7 1.9 330 23 12 6.8 3.7 22000 -14.5 5.9 325 22 11 6.8 3.7 | -14.7 5.5 330 23 12 6.9 3.8 21000 -12.4 9.7 325 22 11 6.9 3.8 | -12.6 9.3 330 23 12 7.1 3.9 20000 -10.4 13.3 330 22 12 6.9 3.8 | -10.5 13.1 330 23 12 7.1 3.9 19500 -9.3 15.3 330 23 12 6.9 3.8 | -9.4 15.1 330 23 12 7.1 3.9 19000 -8.3 17.1 330 22 11 7.2 3.9 | -8.3 17.1 330 23 12 7.8 4.3 18500 -7.2 19.0 330 21 11 7.2 3.9 | -7.2 19.0 330 23 12 7.8 4.3 18000 -6.2 20.8 335 21 11 6.7 3.7 | -5.5 22.1 330 22 11 7.1 3.9 17500 -4.8 23.4 335 19 10 6.5 3.6 | -4.5 23.9 330 21 11 7.2 4.0 17000 -3.9 25.0 335 18 9 7.0 3.9 | -3.5 25.7 330 19 10 6.7 3.7 16500 -2.9 26.8 340 17 9 7.3 4.0 | -2.6 27.3 330 18 9 6.6 3.6 16000 -1.9 28.6 345 16 8 7.6 4.1 | -1.7 28.9 335 17 9 6.8 3.7 15500 -0.8 30.6 345 15 8 8.2 4.5 | -0.7 30.7 335 16 8 7.1 3.9 15000 0.4 32.7 350 14 7 8.2 4.5 | 0.3 32.5 340 15 8 7.2 3.9 14500 1.6 34.9 350 14 7 9.2 5.1 | 1.4 34.5 340 14 7 8.7 4.8 14000 2.9 37.2 350 14 7 9.2 5.0 | 2.6 36.7 345 14 7 8.6 4.7 13500 4.3 39.7 350 13 7 9.1 5.0 | 3.8 38.8 345 14 7 9.3 5.1 13000 5.6 42.1 350 13 7 9.1 5.0 | 5.2 41.4 350 13 7 9.4 5.1 12500 6.9 44.4 350 12 6 8.4 4.6 | 6.5 43.7 350 13 7 8.8 4.8 12000 8.0 46.4 350 12 6 8.2 4.5 | 7.8 46.0 350 13 6 8.7 4.8 11500 9.2 48.6 355 11 6 8.0 4.4 | 9.0 48.2 355 12 6 8.4 4.6 11000 10.4 50.7 360 11 6 7.8 4.3 | 10.2 50.4 355 12 6 8.3 4.6 10500 11.4 52.5 005 11 5 4.3 2.3 | 11.3 52.3 360 11 6 3.1 1.7 10250 11.7 53.1 005 11 5 5.5 3.0 | 11.5 52.7 360 11 6 5.5 3.0 10000 12.4 54.3 010 10 5 10.5 5.7 | 12.2 54.0 360 10 5 11.5 6.3 9750 13.1 55.6 010 10 5 9.9 5.4 | 12.9 55.2 005 9 5 9.9 5.4 9500 13.7 56.7 010 10 5 7.4 4.1 | 13.6 56.5 005 8 4 7.5 4.1 9250 14.2 57.6 010 10 5 5.7 3.1 | 14.0 57.2 010 7 4 6.2 3.4 9000 14.6 58.3 015 10 5 7.1 3.9 | 14.5 58.1 010 6 3 9.2 5.0 8750 15.1 59.2 010 11 6 7.1 3.9 | 15.2 59.4 010 6 3 10.1 5.5 8500 15.5 59.9 010 11 6 5.4 3.0 | 15.9 60.6 010 5 3 8.6 4.7 8250 15.8 60.4 010 11 6 4.5 2.5 | 16.5 61.7 010 5 3 7.6 4.2 8000 16.2 61.2 010 12 6 5.7 3.1 | 17.1 62.8 010 5 3 10.4 5.7 7750 16.6 61.9 010 12 6 5.5 3.0 | 17.9 64.2 015 5 3 10.9 6.0 7500 16.9 62.4 010 11 6 3.9 2.1 | 18.5 65.3 015 5 3 8.4 4.6 7250 17.2 63.0 005 11 6 3.5 1.9 | 19.1 66.4 015 5 3 7.2 3.9 7000 17.5 63.5 360 11 5 4.4 2.4 | 19.7 67.5 015 5 3 12.0 6.6 6750 17.8 64.0 005 9 5 5.3 2.9 | 20.8 69.4 020 5 3 13.3 7.3 6500 18.1 64.6 360 8 4 5.0 2.7 | 21.6 70.9 020 5 3 9.5 5.2 6250 18.4 65.1 360 7 4 5.5 3.0 | 22.3 72.1 020 5 2 10.6 5.8 6000 18.7 65.7 355 6 3 3.9 2.2 | 23.1 73.6 020 5 2 10.1 5.5 5750 19.0 66.2 350 5 2 9.8 5.4 | 24.0 75.2 015 5 2 18.3 10.0 5500 20.2 68.4 350 4 2 24.0 13.2 | 25.9 78.6 015 4 2 32.1 17.6 07/20/2024 at 1500 MDT | 07/20/2024 at 1800 MDT | CAPE... +876.2 LI... -3.2 | CAPE... +806.4 LI... -2.6 CINH... -1.7 K Index... +24.9 | CINH... -0.3 K Index... +31.7 | 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 -61.1 -78.0 325 32 17 2.3 1.3 | -60.3 -76.5 320 36 19 2.2 1.2 45000 -55.4 -67.7 315 51 26 6.0 3.3 | -55.2 -67.4 315 54 28 5.1 2.8 40000 -46.7 -52.1 310 64 33 4.5 2.4 | -47.6 -53.7 310 63 32 4.6 2.5 38000 -44.0 -47.2 310 58 30 4.5 2.5 | -44.9 -48.8 310 57 29 4.6 2.5 36000 -41.3 -42.3 310 51 26 4.5 2.5 | -42.1 -43.8 310 51 26 4.5 2.5 34000 -38.6 -37.5 310 43 22 4.4 2.4 | -39.0 -38.2 310 44 23 5.3 2.9 32000 -35.7 -32.3 310 34 17 4.7 2.6 | -35.5 -31.9 310 37 19 5.5 3.0 30000 -32.0 -25.6 315 28 14 6.3 3.4 | -31.8 -25.2 305 32 16 6.2 3.4 29000 -30.1 -22.2 320 26 13 6.3 3.4 | -30.0 -22.0 305 30 15 6.2 3.4 28000 -28.0 -18.4 325 24 12 9.1 5.0 | -28.0 -18.4 305 28 14 8.8 4.8 27000 -25.4 -13.7 330 23 12 8.9 4.9 | -25.4 -13.7 305 27 14 8.5 4.7 26000 -22.7 -8.9 340 23 12 8.9 4.9 | -22.9 -9.2 310 26 13 8.5 4.7 25000 -20.1 -4.2 350 23 12 8.4 4.6 | -20.3 -4.5 310 25 13 8.7 4.7 24000 -17.7 0.1 345 23 12 7.8 4.3 | -17.7 0.1 315 24 12 8.8 4.8 23000 -15.4 4.3 345 22 11 7.8 4.3 | -15.0 5.0 320 23 12 8.8 4.8 22000 -13.0 8.6 340 21 11 7.0 3.8 | -12.5 9.5 325 22 11 7.3 4.0 21000 -11.1 12.0 335 22 11 6.7 3.7 | -10.6 12.9 325 21 11 6.6 3.6 20000 -9.2 15.4 325 23 12 7.0 3.8 | -8.7 16.3 320 21 11 6.8 3.7 19500 -8.2 17.2 320 24 12 7.3 4.0 | -7.7 18.1 320 21 11 6.9 3.8 19000 -7.2 19.0 320 24 12 7.3 4.0 | -6.8 19.8 320 20 10 6.1 3.4 18500 -6.1 21.0 320 24 12 7.3 4.0 | -5.9 21.4 320 20 10 6.2 3.4 18000 -5.0 23.0 320 24 12 7.4 4.1 | -5.0 23.0 320 20 10 6.4 3.5 17500 -3.8 25.2 325 24 12 7.5 4.1 | -4.1 24.6 320 19 10 6.4 3.5 17000 -2.6 27.3 325 24 12 7.3 4.0 | -3.1 26.4 320 19 10 6.5 3.6 16500 -1.2 29.8 330 23 12 6.3 3.5 | -2.2 28.0 320 19 10 6.9 3.8 16000 -0.3 31.5 330 22 11 6.4 3.5 | -1.2 29.8 320 18 9 6.9 3.8 15500 0.6 33.1 330 19 10 6.5 3.5 | 0.2 32.4 325 17 9 6.9 3.8 15000 1.4 34.5 330 17 9 6.6 3.6 | 1.2 34.2 325 15 8 7.0 3.8 14500 2.3 36.1 330 15 8 6.6 3.6 | 2.1 35.8 325 12 6 5.8 3.2 14000 3.2 37.8 335 13 7 6.6 3.6 | 2.9 37.2 335 9 5 5.8 3.2 13500 4.2 39.6 340 11 5 8.0 4.4 | 3.8 38.8 350 6 3 7.9 4.3 13000 5.3 41.5 345 9 4 8.0 4.4 | 4.8 40.6 020 5 3 7.9 4.4 12500 6.5 43.7 360 7 4 8.4 4.6 | 6.0 42.8 045 6 3 9.4 5.2 12000 7.6 45.7 005 7 3 8.5 4.7 | 7.4 45.3 045 7 3 9.7 5.3 11500 8.8 47.8 010 6 3 9.1 5.0 | 8.8 47.8 050 7 4 9.8 5.4 11000 10.1 50.2 010 6 3 9.3 5.1 | 10.3 50.5 050 7 4 9.8 5.4 10500 11.3 52.3 010 6 3 4.0 2.2 | 11.6 52.9 050 7 4 3.2 1.8 10250 11.6 52.9 010 6 3 7.8 4.3 | 11.8 53.2 050 7 4 7.7 4.2 10000 12.5 54.5 010 6 3 14.5 7.9 | 12.8 55.0 050 8 4 15.7 8.6 9750 13.5 56.3 010 6 3 12.0 6.6 | 13.9 57.0 050 8 4 12.7 7.0 9500 14.3 57.7 010 6 3 9.2 5.0 | 14.7 58.5 050 8 4 8.5 4.6 9250 14.9 58.8 010 6 3 7.8 4.3 | 15.2 59.4 050 8 4 6.6 3.6 9000 15.6 60.1 010 6 3 10.5 5.8 | 15.9 60.6 050 8 4 11.4 6.3 8750 16.4 61.5 010 6 3 11.2 6.1 | 16.8 62.2 050 8 4 12.4 6.8 8500 17.2 63.0 005 6 3 10.1 5.5 | 17.6 63.7 050 8 4 9.9 5.4 8250 17.9 64.2 005 6 3 9.7 5.3 | 18.3 64.9 050 8 4 9.1 5.0 8000 18.7 65.7 005 6 3 10.7 5.8 | 19.0 66.2 050 8 4 10.3 5.6 7750 19.5 67.1 005 6 3 10.9 6.0 | 19.8 67.6 050 8 4 10.6 5.8 7500 20.2 68.4 005 5 3 9.9 5.4 | 20.6 69.1 050 8 4 9.6 5.3 7250 21.0 69.8 005 5 3 10.0 5.5 | 21.3 70.3 050 8 4 9.5 5.2 7000 21.7 71.1 005 5 3 9.8 5.4 | 22.0 71.6 050 8 4 10.1 5.5 6750 22.5 72.5 005 5 3 10.1 5.5 | 22.8 73.0 050 8 4 10.4 5.7 6500 23.2 73.8 005 5 3 10.7 5.9 | 23.6 74.5 050 8 4 10.2 5.6 6250 24.0 75.2 360 5 3 10.2 5.6 | 24.3 75.7 050 8 4 9.9 5.4 6000 24.8 76.6 360 5 3 11.5 6.3 | 25.1 77.2 050 8 4 11.2 6.2 5750 25.9 78.6 360 5 3 19.4 10.6 | 26.1 79.0 050 8 4 15.7 8.6 5500 27.7 81.9 360 5 3 28.8 15.8 | 27.4 81.3 050 8 4 19.1 10.5 ________________________________________________________________________________ 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