Soaring Guidance
Issued by NWS Denver/Boulder, CO
Issued by NWS Denver/Boulder, CO
138 UXUS97 KBOU 230037 SRGBOU Soaring Forecast National Weather Service Denver/Boulder, Colorado 1836 MDT Saturday, June 22, 2024 This forecast is for Sunday, June 23, 2024: If the trigger temperature of 82.4 F/28.0 C is reached...then Thermal Soaring Index....................... Excellent Maximum rate of lift........................ 1112 ft/min (5.6 m/s) Maximum height of thermals.................. 17909 ft MSL (12605 ft AGL) Forecast maximum temperature................... 95.0 F/35.5 C Time of trigger temperature.................... 0945 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................. 15142 ft MSL (9838 ft AGL) Thermal soaring outlook for Monday 06/24....... 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)................ Weak PVA Potential height of wave....................... 19787 ft MSL (14483 ft AGL) Wave soaring outlook for Monday 06/24.......... Fair Remarks... None Sunrise/Sunset.................... 05:32:20 / 20:31:27 MDT Total possible sunshine........... 14 hr 59 min 7 sec (899 min 7 sec) Altitude of sun at 13:01:54 MDT... 73.64 degrees Upper air data from numerical model forecast valid on 06/23/2024 at 0600 MDT Freezing level.................. 16159 ft MSL (10855 ft AGL) Convective condensation level... 17010 ft MSL (11706 ft AGL) Lifted condensation level....... 17753 ft MSL (12449 ft AGL) Lifted index.................... -1.5 K index......................... +20.3 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 -63.2 -81.8 275 57 30 1.6 0.9 M M M M M 45000 -58.8 -73.8 270 74 38 5.6 3.0 M M M M M 40000 -49.8 -57.6 265 75 38 6.5 3.6 M M M M M 38000 -45.9 -50.6 270 63 32 6.5 3.6 M M M M M 36000 -42.0 -43.6 270 52 27 6.5 3.5 M M M M M 34000 -38.2 -36.8 275 40 20 6.4 3.5 M M M M M 32000 -34.4 -29.9 280 28 14 6.2 3.4 M M M M M 30000 -30.0 -22.0 280 19 10 7.4 4.1 46.0 114.9 8.4 M M 29000 -27.8 -18.0 280 15 8 7.4 4.1 45.2 113.3 7.8 M M 28000 -24.9 -12.8 280 11 6 8.4 4.6 44.3 111.7 7.2 M M 27000 -22.4 -8.3 285 10 5 8.4 4.6 43.7 110.6 6.8 M M 26000 -19.9 -3.8 290 9 5 8.4 4.6 43.2 109.7 6.5 M M 25000 -17.4 0.7 295 9 4 7.9 4.4 42.7 108.9 6.2 M M 24000 -15.1 4.8 300 9 5 7.7 4.2 41.9 107.4 5.6 M M 23000 -12.8 9.0 305 10 5 7.7 4.2 41.1 106.1 5.0 M M 22000 -10.6 12.9 305 11 6 7.0 3.9 40.5 104.9 4.5 M M 21000 -8.6 16.5 295 11 6 6.8 3.7 39.3 102.8 3.6 M M 20000 -6.6 20.1 285 13 6 6.9 3.8 38.3 101.0 2.7 M M 19500 -5.6 21.9 280 13 7 6.8 3.7 37.9 100.1 2.3 M M 19000 -4.8 23.4 275 14 7 5.1 2.8 37.2 98.9 1.6 M M 18500 -4.0 24.8 275 14 7 5.2 2.9 36.4 97.5 0.9 M M 18000 -3.3 26.1 270 14 7 5.2 2.8 35.6 96.1 0.2 M M 17500 -2.6 27.3 270 14 7 5.2 2.9 34.8 94.7 -0.5 1087 5.5 17000 -1.8 28.8 270 14 7 5.3 2.9 34.1 93.3 -1.2 1051 5.3 16500 -0.9 30.4 270 14 7 7.4 4.0 33.5 92.3 -1.8 1009 5.1 16000 0.1 32.2 270 13 7 7.2 4.0 33.1 91.5 -2.2 963 4.9 15500 1.2 34.2 270 13 7 7.6 4.1 32.7 90.8 -2.7 917 4.7 15000 2.8 37.0 270 12 6 7.6 4.2 32.1 89.8 -3.2 845 4.3 14500 4.0 39.2 270 11 6 8.1 4.5 31.8 89.3 -3.5 795 4.0 14000 5.2 41.4 270 11 5 8.1 4.4 31.5 88.8 -3.8 746 3.8 13500 6.3 43.3 265 10 5 8.3 4.6 31.3 88.3 -4.1 696 3.5 13000 7.6 45.7 265 10 5 8.4 4.6 31.1 87.9 -4.4 644 3.3 12500 8.8 47.8 265 9 5 8.4 4.6 30.9 87.5 -4.6 593 3.0 12000 9.9 49.8 265 8 4 8.4 4.6 30.6 87.1 -4.9 543 2.8 11500 11.1 52.0 265 8 4 8.1 4.5 30.4 86.7 -5.2 493 2.5 11000 12.3 54.1 265 7 4 7.7 4.2 30.1 86.2 -5.6 444 2.3 10500 13.4 56.1 265 7 4 4.6 2.5 29.8 85.7 -5.9 396 2.0 10250 13.6 56.5 265 7 4 6.1 3.3 29.3 84.8 -6.5 381 1.9 10000 14.3 57.7 265 7 3 11.1 6.1 29.3 84.8 -6.5 352 1.8 9750 15.1 59.2 265 6 3 10.4 5.7 29.4 84.9 -6.5 323 1.6 9500 15.8 60.4 260 6 3 8.2 4.5 29.4 84.9 -6.5 294 1.5 9250 16.2 61.2 260 6 3 5.7 3.1 29.1 84.4 -6.8 273 1.4 9000 16.8 62.2 260 5 3 7.9 4.3 28.9 84.0 -7.0 250 1.3 8750 17.4 63.3 255 5 3 8.7 4.8 28.8 83.8 -7.2 225 1.1 8500 18.0 64.4 255 5 2 7.8 4.3 28.7 83.7 -7.3 199 1.0 8250 18.5 65.3 255 4 2 7.1 3.9 28.5 83.3 -7.5 175 0.9 8000 19.1 66.4 260 4 2 7.3 4.0 28.3 83.0 -7.7 151 0.8 7750 19.6 67.3 260 4 2 7.3 4.0 28.1 82.6 -7.9 127 0.6 7500 20.2 68.4 265 4 2 7.4 4.1 27.9 82.3 -8.1 103 0.5 7250 20.8 69.4 270 4 2 7.3 4.0 27.8 82.0 -8.2 79 0.4 7000 21.3 70.3 275 4 2 8.0 4.4 27.6 81.6 -8.4 54 0.3 6750 21.9 71.4 280 4 2 5.1 2.8 27.4 81.3 -8.6 30 0.2 6500 22.1 71.8 280 5 2 1.3 0.7 26.9 80.3 -9.2 17 0.1 6250 22.0 71.6 275 5 3 -3.2 -1.8 26.1 79.0 -10.0 11 0.1 6000 22.0 71.6 270 6 3 10.3 5.7 25.4 77.6 -10.7 5 0.0 5750 23.1 73.6 280 8 4 0.8 0.4 25.6 78.1 -10.4 M M 5500 20.9 69.6 255 6 3 -53.4 -29.3 22.9 73.2 -13.4 23 0.1 * * * * * * Numerical weather prediction model forecast data valid * * * * * * 06/23/2024 at 0900 MDT | 06/23/2024 at 1200 MDT | CAPE... 0.0 LI... +3.1 | CAPE... 0.0 LI... +2.7 CINH... -0.1 K Index... +8.5 | CINH... -0.1 K Index... +10.0 | 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 -62.5 -80.5 275 49 25 2.4 1.3 | -62.9 -81.2 275 48 25 3.1 1.7 45000 -57.8 -72.0 275 65 33 4.8 2.6 | -57.4 -71.3 275 60 31 4.8 2.6 40000 -49.9 -57.8 265 68 35 6.1 3.3 | -49.5 -57.1 265 65 33 6.1 3.3 38000 -46.3 -51.3 270 58 30 6.1 3.3 | -45.9 -50.6 265 58 30 6.1 3.3 36000 -42.6 -44.7 270 48 25 6.2 3.4 | -42.2 -44.0 265 51 26 6.2 3.4 34000 -38.8 -37.8 270 37 19 6.4 3.5 | -38.4 -37.1 265 41 21 6.4 3.5 32000 -35.0 -31.0 270 27 14 6.2 3.4 | -34.6 -30.3 265 30 15 6.2 3.4 30000 -29.9 -21.8 270 21 11 7.7 4.2 | -29.8 -21.6 260 24 12 7.3 4.0 29000 -27.6 -17.7 265 18 10 7.7 4.2 | -27.6 -17.7 260 22 11 7.3 4.0 28000 -25.3 -13.5 265 16 8 8.2 4.5 | -25.3 -13.5 255 20 10 8.2 4.5 27000 -22.9 -9.2 265 14 7 8.2 4.5 | -22.9 -9.2 255 17 9 8.1 4.5 26000 -20.4 -4.7 270 12 6 8.2 4.5 | -20.5 -4.9 255 15 8 8.1 4.5 25000 -18.0 -0.4 275 10 5 7.9 4.3 | -18.1 -0.6 255 12 6 7.9 4.3 24000 -15.7 3.7 275 9 5 7.7 4.2 | -15.8 3.6 250 12 6 7.7 4.2 23000 -13.4 7.9 280 8 4 7.7 4.2 | -13.5 7.7 250 11 6 7.7 4.2 22000 -11.1 12.0 290 8 4 7.1 3.9 | -11.2 11.8 250 10 5 6.7 3.7 21000 -9.1 15.6 290 8 4 6.8 3.7 | -9.3 15.3 260 9 5 6.2 3.4 20000 -7.1 19.2 295 9 5 6.8 3.7 | -7.5 18.5 265 8 4 6.2 3.4 19500 -6.1 21.0 295 9 5 6.7 3.7 | -6.6 20.1 270 8 4 6.2 3.4 19000 -5.2 22.6 300 10 5 5.8 3.2 | -5.7 21.7 280 8 4 5.9 3.3 18500 -4.3 24.3 305 10 5 5.9 3.2 | -4.8 23.4 285 8 4 6.0 3.3 18000 -3.5 25.7 305 11 6 5.5 3.0 | -4.0 24.8 290 8 4 6.2 3.4 17500 -2.7 27.1 310 11 6 5.3 2.9 | -3.1 26.4 295 8 4 6.3 3.5 17000 -1.9 28.6 315 11 6 5.4 3.0 | -2.2 28.0 300 8 4 6.5 3.6 16500 -1.1 30.0 320 10 5 6.7 3.7 | -1.1 30.0 305 8 4 7.7 4.2 16000 0.4 32.7 325 10 5 6.9 3.8 | 0.6 33.1 310 7 4 7.8 4.3 15500 1.5 34.7 325 10 5 7.8 4.3 | 1.8 35.2 315 7 4 8.2 4.5 15000 2.6 36.7 330 9 5 7.8 4.3 | 3.0 37.4 315 7 4 8.1 4.4 14500 3.8 38.8 330 9 5 8.3 4.6 | 4.2 39.6 315 7 4 8.8 4.8 14000 5.0 41.0 330 9 5 8.3 4.5 | 5.5 41.9 320 7 4 8.7 4.8 13500 6.2 43.2 330 9 4 8.9 4.9 | 6.8 44.2 320 7 3 8.9 4.9 13000 7.5 45.5 330 8 4 9.0 4.9 | 8.1 46.6 320 7 3 8.9 4.9 12500 8.8 47.8 325 8 4 8.8 4.8 | 9.4 48.9 325 6 3 9.1 5.0 12000 10.1 50.2 325 7 4 8.7 4.8 | 10.7 51.3 325 6 3 9.1 5.0 11500 11.4 52.5 320 7 4 8.6 4.7 | 12.1 53.8 325 6 3 9.1 5.0 11000 12.6 54.7 320 7 3 8.2 4.5 | 13.4 56.1 330 6 3 8.7 4.8 10500 13.9 57.0 315 6 3 3.4 1.9 | 14.7 58.5 330 6 3 4.0 2.2 10250 14.0 57.2 320 6 3 4.9 2.7 | 14.8 58.6 335 6 3 5.8 3.2 10000 14.7 58.5 315 6 3 12.2 6.7 | 15.7 60.3 330 5 3 13.1 7.2 9750 15.5 59.9 310 6 3 11.1 6.1 | 16.5 61.7 330 5 3 11.9 6.5 9500 16.3 61.3 305 6 3 8.3 4.6 | 17.4 63.3 330 5 2 8.9 4.9 9250 16.7 62.1 300 6 3 5.9 3.2 | 17.9 64.2 330 5 2 7.2 4.0 9000 17.3 63.1 300 6 3 9.3 5.1 | 18.6 65.5 330 5 2 11.1 6.1 8750 18.0 64.4 295 6 3 10.3 5.6 | 19.4 66.9 330 4 2 11.8 6.5 8500 18.7 65.7 295 6 3 8.8 4.9 | 20.2 68.4 330 4 2 10.1 5.5 8250 19.3 66.7 295 6 3 7.6 4.2 | 20.9 69.6 330 4 2 8.2 4.5 8000 19.9 67.8 300 6 3 8.8 4.8 | 21.6 70.9 330 4 2 10.5 5.7 7750 20.6 69.1 300 6 3 9.3 5.1 | 22.4 72.3 330 4 2 11.8 6.5 7500 21.2 70.2 300 7 4 7.7 4.2 | 23.2 73.8 330 4 2 9.4 5.1 7250 21.7 71.1 300 7 4 6.3 3.5 | 23.9 75.0 330 4 2 7.6 4.2 7000 22.2 72.0 305 7 4 8.4 4.6 | 24.5 76.1 330 4 2 10.5 5.7 6750 22.9 73.2 300 8 4 10.1 5.5 | 25.4 77.7 330 4 2 13.4 7.4 6500 23.6 74.5 300 7 4 7.8 4.3 | 26.3 79.3 330 4 2 11.3 6.2 6250 24.0 75.2 295 6 3 6.8 3.7 | 27.1 80.8 330 4 2 10.6 5.8 6000 24.5 76.1 290 6 3 6.7 3.7 | 27.9 82.2 330 4 2 9.2 5.0 5750 25.1 77.2 285 5 2 11.6 6.4 | 28.7 83.7 325 3 2 16.3 8.9 5500 26.3 79.3 275 4 2 21.3 11.7 | 30.5 86.9 330 3 2 33.1 18.2 06/23/2024 at 1500 MDT | 06/23/2024 at 1800 MDT | CAPE... 0.0 LI... +2.3 | CAPE... 0.0 LI... +0.6 CINH... 0.0 K Index... +13.8 | CINH... 0.0 K Index... +18.2 | 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 -63.5 -82.3 275 49 25 3.6 2.0 | -63.6 -82.5 280 46 24 3.5 1.9 45000 -56.9 -70.4 275 58 30 5.0 2.8 | -57.0 -70.6 275 55 28 5.3 2.9 40000 -48.9 -56.0 265 67 34 7.0 3.8 | -48.6 -55.5 270 64 33 7.0 3.8 38000 -44.7 -48.5 265 66 34 7.0 3.8 | -44.4 -47.9 265 67 34 7.0 3.8 36000 -40.5 -40.9 260 66 34 6.6 3.6 | -40.2 -40.4 260 70 36 6.7 3.7 34000 -36.9 -34.4 260 55 28 6.0 3.3 | -36.5 -33.7 265 61 31 6.2 3.4 32000 -33.2 -27.8 260 43 22 5.9 3.2 | -32.8 -27.0 265 52 27 6.0 3.3 30000 -28.5 -19.3 265 35 18 7.2 4.0 | -28.0 -18.4 270 43 22 7.2 4.0 29000 -26.3 -15.3 270 31 16 7.2 4.0 | -25.8 -14.4 275 40 20 7.2 4.0 28000 -24.2 -11.6 270 27 14 7.0 3.8 | -23.7 -10.7 275 36 18 6.5 3.5 27000 -22.1 -7.8 265 22 11 7.0 3.9 | -21.7 -7.1 275 29 15 6.5 3.6 26000 -20.0 -4.0 260 17 9 7.1 3.9 | -19.8 -3.6 275 23 12 6.5 3.6 25000 -17.9 -0.2 255 12 6 7.3 4.0 | -17.8 -0.0 275 17 9 6.9 3.8 24000 -15.7 3.7 245 11 6 7.4 4.1 | -15.7 3.7 275 17 9 7.3 4.0 23000 -13.5 7.7 240 11 6 7.4 4.1 | -13.6 7.5 270 16 8 7.4 4.1 22000 -11.3 11.7 235 11 6 6.8 3.7 | -11.4 11.5 265 16 8 6.9 3.8 21000 -9.4 15.1 235 11 6 6.6 3.6 | -9.6 14.7 270 16 8 6.5 3.6 20000 -7.5 18.5 240 11 6 6.7 3.7 | -7.8 18.0 275 16 8 6.7 3.7 19500 -6.6 20.1 240 11 6 6.7 3.7 | -6.8 19.8 275 16 8 6.8 3.7 19000 -5.6 21.9 245 11 6 6.8 3.8 | -5.8 21.6 275 15 8 7.6 4.2 18500 -4.6 23.7 250 12 6 6.8 3.8 | -4.7 23.5 275 14 7 7.6 4.2 18000 -3.6 25.5 255 13 6 7.4 4.1 | -3.6 25.5 275 14 7 7.8 4.3 17500 -2.4 27.7 260 13 6 7.7 4.2 | -2.4 27.7 275 13 7 7.9 4.4 17000 -1.3 29.7 265 13 6 7.8 4.3 | -1.2 29.8 280 12 6 8.0 4.4 16500 -0.0 32.0 270 13 6 8.5 4.7 | 0.1 32.2 280 11 6 8.7 4.8 16000 1.2 34.2 275 13 7 8.5 4.7 | 1.4 34.5 280 11 6 8.6 4.7 15500 3.1 37.6 285 13 6 8.4 4.6 | 3.4 38.1 280 9 5 9.1 5.0 15000 4.3 39.7 290 12 6 8.4 4.6 | 4.7 40.5 275 8 4 9.1 5.0 14500 5.5 41.9 295 11 6 8.2 4.5 | 6.1 43.0 270 7 4 9.1 5.0 14000 6.8 44.2 300 10 5 8.2 4.5 | 7.4 45.3 265 6 3 9.1 5.0 13500 8.1 46.6 305 9 4 8.5 4.6 | 8.7 47.7 260 5 3 9.4 5.1 13000 9.4 48.9 305 7 3 8.5 4.7 | 10.1 50.2 250 4 2 9.4 5.2 12500 10.6 51.1 310 5 3 8.3 4.6 | 11.5 52.7 235 3 2 9.1 5.0 12000 11.8 53.2 315 4 2 8.2 4.5 | 12.8 55.0 230 3 1 8.9 4.9 11500 13.1 55.6 320 3 1 8.5 4.7 | 14.2 57.6 215 2 1 8.7 4.8 11000 14.4 57.9 325 2 1 8.6 4.7 | 15.5 59.9 215 2 1 8.3 4.6 10500 15.7 60.3 325 2 1 5.1 2.8 | 16.8 62.2 220 1 1 4.7 2.6 10250 15.9 60.6 325 2 1 6.5 3.6 | 17.1 62.8 225 1 1 6.0 3.3 10000 16.7 62.1 325 2 1 12.2 6.7 | 17.8 64.0 245 1 0 11.7 6.4 9750 17.5 63.5 325 2 1 11.2 6.1 | 18.6 65.5 270 1 0 10.5 5.8 9500 18.3 64.9 325 2 1 9.8 5.4 | 19.4 66.9 290 1 0 9.6 5.2 9250 18.9 66.0 325 2 1 8.6 4.7 | 20.0 68.0 295 1 1 8.5 4.6 9000 19.7 67.5 325 2 1 10.5 5.8 | 20.7 69.3 300 1 1 9.6 5.3 8750 20.4 68.7 320 2 1 10.9 6.0 | 21.5 70.7 300 1 1 9.7 5.3 8500 21.2 70.2 320 2 1 10.1 5.6 | 22.2 72.0 300 2 1 9.7 5.3 8250 22.0 71.6 320 2 1 9.3 5.1 | 22.9 73.2 300 2 1 9.7 5.3 8000 22.7 72.9 320 2 1 10.0 5.5 | 23.6 74.5 300 2 1 9.7 5.3 7750 23.4 74.1 315 2 1 10.5 5.7 | 24.3 75.7 300 2 1 9.8 5.4 7500 24.2 75.6 315 2 1 10.1 5.5 | 25.1 77.2 300 2 1 9.9 5.5 7250 24.9 76.8 315 2 1 10.0 5.5 | 25.8 78.4 300 2 1 10.2 5.6 7000 25.7 78.3 315 2 1 9.8 5.4 | 26.6 79.9 300 2 1 9.9 5.4 6750 26.4 79.5 310 2 1 10.0 5.5 | 27.3 81.1 300 2 1 9.8 5.4 6500 27.2 81.0 310 2 1 10.8 5.9 | 28.1 82.6 300 2 1 10.7 5.9 6250 28.0 82.4 310 2 1 11.6 6.4 | 28.9 84.0 300 3 1 11.8 6.5 6000 28.9 84.0 305 2 1 9.5 5.2 | 29.7 85.5 300 3 1 10.4 5.7 5750 29.6 85.3 305 3 1 15.4 8.5 | 30.5 86.9 300 3 1 11.3 6.2 5500 31.4 88.5 305 2 1 31.5 17.3 | 31.6 88.9 300 3 1 18.3 10.0 ________________________________________________________________________________ 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