Soaring Guidance
Issued by NWS Denver/Boulder, CO
Issued by NWS Denver/Boulder, CO
514 UXUS97 KBOU 110023 SRGBOU Soaring Forecast National Weather Service Denver/Boulder, Colorado 1823 MDT Wednesday, July 10, 2024 This forecast is for Thursday, July 11, 2024: If the trigger temperature of 85.1 F/29.5 C is reached...then Thermal Soaring Index....................... Excellent Maximum rate of lift........................ 1596 ft/min (8.1 m/s) Maximum height of thermals.................. 21738 ft MSL (16453 ft AGL) Forecast maximum temperature................... 96.0 F/36.0 C Time of trigger temperature.................... 1045 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................. 16162 ft MSL (10877 ft AGL) Thermal soaring outlook for Friday 07/12....... Excellent 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....................... 15103 ft MSL (9818 ft AGL) Wave soaring outlook for Friday 07/12.......... Poor Remarks... Sunrise/Sunset.................... 05:41:44 / 20:28:31 MDT Total possible sunshine........... 14 hr 46 min 47 sec (886 min 47 sec) Altitude of sun at 13:05:07 MDT... 72.15 degrees Upper air data from numerical model forecast valid on 07/11/2024 at 0600 MDT Freezing level.................. 16045 ft MSL (10760 ft AGL) Convective condensation level... 18106 ft MSL (12821 ft AGL) Lifted condensation level....... 19244 ft MSL (13959 ft AGL) Lifted index.................... -2.9 K index......................... +20.5 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 -59.4 -74.9 360 22 11 2.3 1.3 M M M M M 45000 -56.2 -69.2 005 31 16 1.9 1.0 M M M M M 40000 -52.4 -62.3 005 37 19 5.6 3.1 M M M M M 38000 -49.1 -56.4 360 37 19 5.6 3.1 M M M M M 36000 -45.7 -50.3 360 37 19 5.6 3.1 M M M M M 34000 -41.5 -42.7 355 33 17 7.2 4.0 M M M M M 32000 -37.2 -35.0 345 29 15 7.1 3.9 M M M M M 30000 -32.3 -26.1 345 26 14 8.3 4.5 43.4 110.1 6.0 M M 29000 -29.9 -21.8 340 25 13 8.3 4.5 42.9 109.2 5.6 M M 28000 -27.4 -17.3 340 24 12 7.9 4.3 42.4 108.4 5.3 M M 27000 -24.6 -12.3 345 23 12 7.7 4.2 41.3 106.3 4.5 M M 26000 -22.3 -8.1 345 21 11 7.7 4.2 40.5 104.9 3.9 M M 25000 -20.0 -4.0 350 20 11 6.9 3.8 39.9 103.8 3.4 M M 24000 -18.2 -0.8 345 18 9 6.3 3.4 38.5 101.2 2.2 M M 23000 -16.4 2.5 340 16 8 6.3 3.5 37.2 99.0 1.2 M M 22000 -14.5 5.9 335 15 8 7.0 3.9 36.1 96.9 0.2 M M 21000 -12.3 9.9 340 14 7 7.4 4.1 35.2 95.3 -0.6 1525 7.7 20000 -10.2 13.6 345 13 6 7.4 4.1 34.4 93.8 -1.4 1431 7.3 19500 -9.1 15.6 345 12 6 7.7 4.2 34.0 93.2 -1.7 1383 7.0 19000 -7.9 17.8 350 12 6 8.8 4.8 33.8 92.8 -1.9 1332 6.8 18500 -6.6 20.1 350 12 6 8.7 4.8 33.6 92.4 -2.1 1279 6.5 18000 -5.3 22.5 350 13 7 8.8 4.8 33.4 92.1 -2.3 1226 6.2 17500 -4.0 24.8 355 14 7 8.9 4.9 33.2 91.8 -2.5 1172 6.0 17000 -2.7 27.1 355 15 8 8.9 4.9 33.1 91.6 -2.7 1118 5.7 16500 -1.4 29.5 355 16 8 8.9 4.9 32.9 91.3 -2.9 1065 5.4 16000 -0.1 31.8 355 17 9 8.8 4.8 32.8 91.0 -3.0 1011 5.1 15500 1.2 34.2 350 18 9 9.4 5.2 32.7 90.8 -3.2 957 4.9 15000 2.6 36.7 350 18 9 9.4 5.2 32.6 90.7 -3.3 900 4.6 14500 4.0 39.2 350 19 10 9.4 5.2 32.6 90.7 -3.3 844 4.3 14000 5.4 41.7 350 18 9 9.5 5.2 32.5 90.6 -3.4 787 4.0 13500 7.5 45.5 350 17 9 8.9 4.9 32.4 90.4 -3.6 703 3.6 13000 8.8 47.8 345 15 8 8.9 4.9 32.3 90.1 -3.7 649 3.3 12500 10.1 50.2 345 14 7 8.6 4.7 32.2 89.9 -3.9 595 3.0 12000 11.3 52.3 340 12 6 8.5 4.7 32.0 89.5 -4.1 542 2.8 11500 12.6 54.7 340 11 5 8.3 4.6 31.8 89.2 -4.3 490 2.5 11000 13.8 56.8 330 9 5 8.0 4.4 31.5 88.7 -4.6 438 2.2 10500 15.0 59.0 325 8 4 4.1 2.2 31.2 88.2 -4.8 388 2.0 10250 15.2 59.4 320 8 4 5.4 2.9 30.7 87.2 -5.4 375 1.9 10000 15.9 60.6 315 8 4 10.6 5.8 30.6 87.2 -5.4 346 1.8 9750 16.6 61.9 305 7 4 9.7 5.3 30.6 87.1 -5.5 318 1.6 9500 17.3 63.1 300 7 4 6.6 3.6 30.6 87.0 -5.5 291 1.5 9250 17.6 63.7 295 7 4 4.1 2.2 30.2 86.3 -6.0 273 1.4 9000 18.1 64.6 295 7 3 7.9 4.3 29.9 85.8 -6.3 253 1.3 8750 18.7 65.7 285 7 3 9.3 5.1 29.8 85.7 -6.3 226 1.1 8500 19.3 66.7 280 6 3 6.5 3.5 29.7 85.4 -6.5 200 1.0 8250 19.7 67.5 280 6 3 4.3 2.4 29.3 84.8 -6.9 182 0.9 8000 20.0 68.0 280 6 3 6.4 3.5 29.0 84.1 -7.2 164 0.8 7750 20.6 69.1 275 6 3 7.1 3.9 28.8 83.8 -7.5 141 0.7 7500 20.9 69.6 270 5 3 3.7 2.0 28.4 83.2 -7.8 122 0.6 7250 21.1 70.0 270 5 3 2.1 1.2 27.9 82.2 -8.4 110 0.6 7000 21.3 70.3 265 5 2 3.0 1.6 27.3 81.2 -9.0 98 0.5 6750 21.4 70.5 260 4 2 0.4 0.2 26.8 80.2 -9.6 87 0.4 6500 21.2 70.2 255 4 2 -2.8 -1.5 25.9 78.6 -10.6 84 0.4 6250 21.0 69.8 250 4 2 -2.5 -1.4 25.0 76.9 -11.6 84 0.4 6000 20.7 69.3 250 4 2 -3.2 -1.7 24.0 75.3 -12.5 84 0.4 5750 20.3 68.5 240 4 2 -10.2 -5.6 22.9 73.2 -13.7 89 0.5 5500 19.1 66.4 220 4 2 -19.9 -10.9 21.0 69.7 -15.7 118 0.6 * * * * * * Numerical weather prediction model forecast data valid * * * * * * 07/11/2024 at 0900 MDT | 07/11/2024 at 1200 MDT | CAPE... +1.8 LI... -0.1 | CAPE... +135.0 LI... -0.7 CINH... -29.0 K Index... +21.5 | CINH... -23.7 K Index... +20.7 | 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 -59.0 -74.2 010 22 11 2.3 1.2 | -58.9 -74.0 020 18 9 2.8 1.5 45000 -55.8 -68.4 005 31 16 1.8 1.0 | -55.4 -67.7 005 27 14 1.4 0.8 40000 -52.6 -62.7 005 40 21 5.4 2.9 | -52.4 -62.3 360 39 20 5.6 3.1 38000 -49.3 -56.7 005 41 21 5.5 3.0 | -49.0 -56.2 360 39 20 5.7 3.1 36000 -45.6 -50.1 005 43 22 5.9 3.2 | -45.6 -50.1 360 40 20 5.7 3.1 34000 -41.2 -42.2 005 38 20 7.3 4.0 | -41.5 -42.7 005 38 20 6.9 3.8 32000 -36.8 -34.2 005 34 17 7.4 4.1 | -37.4 -35.3 005 36 19 6.7 3.7 30000 -32.1 -25.8 005 31 16 8.0 4.4 | -31.9 -25.4 010 32 16 8.5 4.7 29000 -29.7 -21.5 005 29 15 8.0 4.4 | -29.3 -20.7 010 30 15 8.5 4.7 28000 -27.3 -17.1 005 28 14 7.9 4.3 | -26.8 -16.2 010 28 14 8.3 4.5 27000 -25.0 -13.0 005 26 14 7.8 4.3 | -24.3 -11.7 005 26 13 8.3 4.6 26000 -22.6 -8.7 360 25 13 7.8 4.3 | -21.8 -7.2 005 24 12 8.3 4.6 25000 -20.3 -4.5 355 24 12 7.4 4.1 | -19.4 -2.9 005 22 11 7.1 3.9 24000 -18.3 -0.9 350 21 11 6.4 3.5 | -17.5 0.5 360 20 11 6.3 3.5 23000 -16.4 2.5 345 19 10 6.5 3.5 | -15.6 3.9 355 19 10 6.4 3.5 22000 -14.5 5.9 340 16 8 6.7 3.7 | -13.7 7.3 350 17 9 6.5 3.6 21000 -12.5 9.5 340 15 7 6.9 3.8 | -11.8 10.8 340 16 8 6.6 3.6 20000 -10.5 13.1 340 13 7 7.0 3.8 | -9.9 14.2 335 15 8 6.8 3.7 19500 -9.5 14.9 340 12 6 7.0 3.9 | -8.9 16.0 330 15 8 7.1 3.9 19000 -7.8 18.0 345 12 6 8.0 4.4 | -7.8 18.0 325 15 7 8.2 4.5 18500 -6.6 20.1 345 12 6 8.1 4.4 | -6.6 20.1 325 14 7 8.1 4.5 18000 -5.4 22.3 345 11 6 8.9 4.9 | -5.4 22.3 320 14 7 8.6 4.7 17500 -4.1 24.6 350 11 6 8.9 4.9 | -4.2 24.4 320 13 7 8.7 4.8 17000 -2.8 27.0 350 11 6 9.0 5.0 | -2.9 26.8 320 13 6 8.8 4.8 16500 -1.4 29.5 350 11 5 9.1 5.0 | -1.6 29.1 320 12 6 9.0 4.9 16000 -0.1 31.8 350 10 5 9.2 5.0 | -0.3 31.5 325 11 6 9.0 4.9 15500 1.3 34.3 350 10 5 9.4 5.2 | 1.7 35.1 325 10 5 9.1 5.0 15000 2.7 36.9 350 10 5 9.4 5.2 | 3.1 37.6 330 9 5 9.1 5.0 14500 4.1 39.4 350 11 5 9.6 5.3 | 4.5 40.1 335 8 4 9.5 5.2 14000 5.5 41.9 350 11 6 9.6 5.3 | 5.9 42.6 340 8 4 9.5 5.2 13500 7.0 44.6 355 11 6 9.6 5.3 | 7.3 45.1 345 8 4 9.2 5.1 13000 8.4 47.1 355 12 6 9.6 5.3 | 8.6 47.5 350 8 4 9.2 5.1 12500 9.8 49.6 355 12 6 9.6 5.2 | 10.0 50.0 350 8 4 9.4 5.2 12000 11.2 52.2 355 12 6 9.5 5.2 | 11.4 52.5 355 8 4 9.4 5.2 11500 12.7 54.9 355 12 6 9.1 5.0 | 12.8 55.0 360 8 4 9.4 5.2 11000 14.0 57.2 355 11 6 8.5 4.7 | 14.2 57.6 360 8 4 9.5 5.2 10500 15.2 59.4 350 11 6 4.0 2.2 | 15.4 59.7 005 8 4 4.2 2.3 10250 15.4 59.7 355 11 5 5.5 3.0 | 15.7 60.3 005 8 4 7.5 4.1 10000 16.2 61.2 350 10 5 12.1 6.6 | 16.6 61.9 005 8 4 13.3 7.3 9750 17.0 62.6 350 9 5 11.0 6.0 | 17.5 63.5 010 8 4 11.9 6.5 9500 17.8 64.0 345 9 5 7.9 4.3 | 18.3 64.9 010 8 4 8.0 4.4 9250 18.2 64.8 345 8 4 5.2 2.8 | 18.8 65.8 010 7 4 6.6 3.6 9000 18.7 65.7 340 8 4 8.7 4.8 | 19.4 66.9 010 7 4 10.8 5.9 8750 19.4 66.9 335 7 4 9.9 5.4 | 20.2 68.4 010 7 3 11.1 6.1 8500 20.1 68.2 330 7 4 7.1 3.9 | 21.0 69.8 010 6 3 9.0 5.0 8250 20.5 68.9 325 6 3 4.8 2.6 | 21.6 70.9 010 6 3 7.0 3.8 8000 20.9 69.6 320 6 3 7.0 3.8 | 22.1 71.8 010 6 3 10.6 5.8 7750 21.5 70.7 315 6 3 7.7 4.2 | 23.1 73.6 015 6 3 12.3 6.7 7500 21.9 71.4 310 6 3 4.2 2.3 | 23.8 74.8 015 6 3 8.9 4.9 7250 22.1 71.8 310 5 3 2.3 1.3 | 24.4 75.9 015 6 3 7.1 3.9 7000 22.3 72.1 305 5 3 3.8 2.1 | 25.0 77.0 015 6 3 11.3 6.2 6750 22.6 72.7 300 5 3 5.6 3.0 | 26.1 79.0 015 5 3 14.0 7.7 6500 23.0 73.4 295 4 2 5.0 2.8 | 27.0 80.6 020 5 3 10.6 5.8 6250 23.4 74.1 290 4 2 5.1 2.8 | 27.7 81.9 020 5 3 10.7 5.9 6000 23.7 74.7 280 3 2 2.9 1.6 | 28.5 83.3 020 5 3 8.8 4.8 5750 23.9 75.0 275 2 1 8.2 4.5 | 29.3 84.7 020 5 3 15.3 8.4 5500 25.2 77.4 270 2 1 24.1 13.2 | 31.0 87.8 020 5 2 32.0 17.6 07/11/2024 at 1500 MDT | 07/11/2024 at 1800 MDT | CAPE... +171.7 LI... -0.5 | CAPE... +114.0 LI... -0.2 CINH... -17.6 K Index... +21.5 | CINH... -48.9 K Index... +20.7 | 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 -59.1 -74.4 025 13 7 3.0 1.7 | -59.3 -74.7 010 10 5 3.0 1.6 45000 -55.4 -67.7 010 21 11 1.2 0.7 | -55.7 -68.3 355 18 9 1.3 0.7 40000 -52.5 -62.5 355 38 20 5.5 3.0 | -52.6 -62.7 355 37 19 5.9 3.2 38000 -49.2 -56.6 355 41 21 5.5 3.0 | -49.1 -56.4 355 40 21 5.8 3.2 36000 -45.9 -50.6 355 43 22 5.8 3.2 | -45.6 -50.1 360 43 22 6.2 3.4 34000 -41.5 -42.7 360 39 20 7.5 4.1 | -41.1 -42.0 355 40 21 7.7 4.2 32000 -37.0 -34.6 360 35 18 7.3 4.0 | -36.5 -33.7 350 38 19 7.8 4.3 30000 -32.0 -25.6 355 29 15 8.4 4.6 | -31.5 -24.7 345 33 17 8.4 4.6 29000 -29.5 -21.1 355 27 14 8.4 4.6 | -29.0 -20.2 345 31 16 8.4 4.6 28000 -26.4 -15.5 350 24 12 8.6 4.7 | -25.9 -14.6 340 29 15 8.1 4.5 27000 -23.8 -10.8 345 22 11 8.6 4.7 | -23.5 -10.3 340 26 14 8.2 4.5 26000 -21.2 -6.2 340 20 11 8.6 4.7 | -21.1 -6.0 335 24 13 8.2 4.5 25000 -18.7 -1.7 335 19 10 7.1 3.9 | -18.7 -1.7 330 23 12 7.0 3.9 24000 -16.7 1.9 335 20 10 6.6 3.6 | -16.7 1.9 330 22 11 6.8 3.7 23000 -14.8 5.4 330 21 11 6.7 3.7 | -14.8 5.4 325 21 11 6.8 3.7 22000 -12.8 9.0 330 21 11 6.9 3.8 | -12.8 9.0 325 21 11 7.5 4.1 21000 -10.8 12.6 330 20 10 7.0 3.8 | -10.6 12.9 330 19 10 7.6 4.2 20000 -8.8 16.2 335 18 9 7.1 3.9 | -8.4 16.9 330 16 8 7.7 4.2 19500 -7.8 18.0 335 18 9 7.4 4.1 | -7.3 18.9 330 15 8 7.9 4.3 19000 -6.7 19.9 335 17 9 7.9 4.3 | -6.1 21.0 330 15 8 8.1 4.5 18500 -5.6 21.9 335 15 8 7.8 4.3 | -4.9 23.2 335 14 7 8.1 4.4 18000 -4.4 24.1 335 14 7 8.9 4.9 | -3.7 25.3 335 13 7 8.8 4.8 17500 -3.0 26.6 335 13 7 9.0 4.9 | -2.3 27.9 335 12 6 8.8 4.8 17000 -1.7 28.9 335 13 7 9.0 4.9 | -1.0 30.2 340 11 6 9.0 4.9 16500 -0.3 31.5 340 12 6 9.0 4.9 | 0.4 32.7 340 10 5 9.3 5.1 16000 1.0 33.8 340 11 6 9.0 4.9 | 1.8 35.2 340 9 5 9.3 5.1 15500 2.3 36.1 340 10 5 8.9 4.9 | 3.2 37.8 335 8 4 9.2 5.0 15000 3.6 38.5 340 9 4 8.9 4.9 | 4.5 40.1 335 7 4 9.2 5.0 14500 5.0 41.0 345 8 4 9.2 5.0 | 5.9 42.6 335 6 3 9.2 5.0 14000 6.3 43.3 345 7 3 9.3 5.1 | 7.3 45.1 335 6 3 9.2 5.0 13500 7.7 45.9 345 6 3 9.2 5.1 | 8.6 47.5 330 5 3 9.2 5.1 13000 9.7 49.5 345 5 3 9.2 5.0 | 10.0 50.0 330 5 2 9.3 5.1 12500 11.1 52.0 340 5 3 9.6 5.2 | 12.1 53.8 325 4 2 9.3 5.1 12000 12.5 54.5 340 5 3 9.6 5.3 | 13.4 56.1 320 4 2 9.3 5.1 11500 14.0 57.2 340 5 2 9.6 5.3 | 14.8 58.6 315 4 2 9.4 5.1 11000 15.4 59.7 335 5 2 10.0 5.5 | 16.2 61.2 310 4 2 9.6 5.3 10500 16.5 61.7 330 4 2 3.6 2.0 | 17.4 63.3 305 4 2 4.1 2.2 10250 16.9 62.4 330 4 2 8.6 4.7 | 17.7 63.9 305 4 2 8.1 4.4 10000 17.8 64.0 330 4 2 14.3 7.8 | 18.6 65.5 305 5 2 13.3 7.3 9750 18.8 65.8 325 4 2 12.3 6.7 | 19.5 67.1 300 5 2 12.0 6.6 9500 19.6 67.3 325 4 2 7.2 3.9 | 20.3 68.5 295 5 3 6.9 3.8 9250 20.0 68.0 325 4 2 6.9 3.8 | 20.7 69.3 295 5 3 6.2 3.4 9000 20.8 69.4 320 4 2 12.8 7.0 | 21.4 70.5 295 5 3 12.3 6.7 8750 21.8 71.2 320 4 2 12.3 6.8 | 22.3 72.1 290 6 3 12.1 6.7 8500 22.6 72.7 320 4 2 8.8 4.8 | 23.1 73.6 290 6 3 8.5 4.7 8250 23.1 73.6 315 4 2 6.0 3.3 | 23.6 74.5 285 6 3 5.3 2.9 8000 23.7 74.7 315 4 2 11.4 6.3 | 24.1 75.4 285 6 3 10.5 5.8 7750 24.7 76.5 315 4 2 13.6 7.4 | 25.1 77.2 285 7 3 13.1 7.2 7500 25.5 77.9 310 4 2 9.0 4.9 | 25.9 78.6 280 7 4 8.7 4.8 7250 26.1 79.0 310 4 2 7.5 4.1 | 26.5 79.7 280 7 4 6.8 3.7 7000 26.8 80.2 310 4 2 11.3 6.2 | 27.0 80.6 280 7 4 10.4 5.7 6750 27.8 82.0 305 4 2 13.5 7.4 | 28.0 82.4 275 7 4 12.5 6.9 6500 28.6 83.5 305 4 2 10.4 5.7 | 28.8 83.8 275 7 4 9.7 5.3 6250 29.4 84.9 305 4 2 11.4 6.3 | 29.5 85.1 275 7 4 8.2 4.5 6000 30.2 86.4 300 4 2 8.1 4.4 | 30.1 86.2 275 7 4 11.6 6.4 5750 30.9 87.6 300 4 2 13.8 7.6 | 31.2 88.2 275 7 4 15.2 8.3 5500 32.6 90.7 305 4 2 32.8 18.0 | 32.2 90.0 275 7 3 11.5 6.3 ________________________________________________________________________________ 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