Soaring Guidance
Issued by NWS Denver/Boulder, CO
Issued by NWS Denver/Boulder, CO
267 UXUS97 KBOU 081308 SRGBOU Soaring Forecast National Weather Service Denver/Boulder, Colorado 0708 MDT Saturday, June 8, 2024 This forecast is for Saturday, June 8, 2024: If the trigger temperature of 80.9 F/27.2 C is reached...then Thermal Soaring Index....................... Fair Maximum rate of lift........................ 381 ft/min (1.9 m/s) Maximum height of thermals.................. 10414 ft MSL (5150 ft AGL) Forecast maximum temperature................... 83.0 F/28.8 C Time of trigger temperature.................... 1145 MDT Time of overdevelopment........................ 1900 MDT Middle/high clouds during soaring window....... Broken/overcast thin middle Surface winds during soaring window............ 20 mph or less Height of the -3 thermal index................. 7483 ft MSL (2219 ft AGL) Thermal soaring outlook for Sunday 06/09....... Poor Wave Soaring Index............................. Poor Wave Soaring Index trend (to 1800 MDT)......... Height of stable layer (12-18K ft MSL)......... None Weak PVA/NVA (through 1800 MDT)................ Weak PVA Potential height of wave....................... 19561 ft MSL (14297 ft AGL) Wave soaring outlook for Sunday 06/09.......... Poor Remarks... Sunrise/Sunset.................... 05:31:11 / 20:26:15 MDT Total possible sunshine........... 14 hr 55 min 4 sec (895 min 4 sec) Altitude of sun at 12:58:43 MDT... 73.17 degrees Upper air data from numerical model forecast valid on 06/08/2024 at 0600 MDT Freezing level.................. 15782 ft MSL (10518 ft AGL) Convective condensation level... 15165 ft MSL (9901 ft AGL) Lifted condensation level....... 14126 ft MSL (8862 ft AGL) Lifted index.................... -3.0 K index......................... +29.9 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 -60.1 -76.2 285 21 11 0.2 0.1 M M M M M 45000 -59.1 -74.4 270 30 16 1.9 1.1 M M M M M 40000 -55.7 -68.3 250 34 17 7.5 4.1 M M M M M 38000 -51.5 -60.7 250 40 21 7.0 3.9 M M M M M 36000 -47.3 -53.1 255 46 24 7.1 3.9 M M M M M 34000 -42.4 -44.3 255 48 25 8.5 4.7 M M M M M 32000 -36.7 -34.1 255 48 25 8.4 4.6 M M M M M 30000 -31.6 -24.9 255 42 22 8.4 4.6 44.0 111.2 11.9 M M 29000 -29.1 -20.4 255 39 20 8.4 4.6 43.5 110.4 11.7 M M 28000 -26.6 -15.9 255 35 18 7.6 4.2 43.2 109.7 11.5 M M 27000 -24.6 -12.3 255 33 17 6.7 3.7 41.9 107.4 10.6 M M 26000 -22.6 -8.7 255 30 16 6.8 3.7 40.7 105.3 9.8 M M 25000 -20.6 -5.1 255 28 14 6.9 3.8 39.7 103.5 9.1 M M 24000 -18.7 -1.7 250 27 14 6.2 3.4 38.4 101.1 8.0 M M 23000 -16.9 1.6 250 28 14 6.2 3.4 37.1 98.7 7.0 M M 22000 -15.1 4.8 250 28 14 6.3 3.4 35.9 96.6 6.0 M M 21000 -12.8 9.0 255 29 15 8.0 4.4 35.1 95.1 5.4 M M 20000 -10.5 13.1 260 31 16 8.1 4.4 34.5 94.0 4.8 M M 19500 -9.3 15.3 260 32 16 8.1 4.4 34.2 93.6 4.6 M M 19000 -8.1 17.4 260 32 16 8.4 4.6 34.0 93.1 4.4 M M 18500 -6.9 19.6 260 31 16 8.4 4.6 33.7 92.7 4.2 M M 18000 -5.6 21.9 260 30 15 8.5 4.7 33.5 92.3 4.0 M M 17500 -4.4 24.1 260 28 14 8.8 4.8 33.3 92.0 3.8 M M 17000 -3.1 26.4 255 26 13 8.9 4.9 33.2 91.7 3.6 M M 16500 -1.9 28.6 255 24 12 7.9 4.4 33.0 91.3 3.4 M M 16000 -0.7 30.7 255 21 11 7.8 4.3 32.6 90.7 3.1 M M 15500 0.4 32.7 250 19 10 8.0 4.4 32.3 90.1 2.8 M M 15000 2.2 36.0 250 15 8 8.4 4.6 31.9 89.5 2.4 M M 14500 3.4 38.1 250 13 7 8.5 4.6 31.7 89.1 2.1 M M 14000 4.6 40.3 245 12 6 8.5 4.7 31.5 88.7 1.9 M M 13500 5.8 42.4 245 11 6 8.3 4.6 31.3 88.3 1.7 M M 13000 7.0 44.6 245 10 5 8.0 4.4 31.0 87.8 1.4 M M 12500 8.2 46.8 245 10 5 8.1 4.4 30.8 87.4 1.2 M M 12000 9.5 49.1 245 10 5 8.4 4.6 30.5 86.9 1.0 M M 11500 10.7 51.3 240 10 5 8.3 4.5 30.3 86.5 0.7 M M 11000 11.8 53.2 230 10 5 7.2 3.9 30.0 86.0 0.4 M M 10500 12.9 55.2 220 10 5 3.5 1.9 29.6 85.3 0.1 M M 10250 13.0 55.4 220 10 5 4.0 2.2 29.0 84.1 -0.5 371 1.9 10000 13.6 56.5 215 9 5 9.4 5.2 28.8 83.9 -0.7 346 1.8 9750 14.2 57.6 210 9 4 8.0 4.4 28.7 83.7 -0.8 321 1.6 9500 14.8 58.6 205 8 4 8.1 4.4 28.6 83.5 -1.0 295 1.5 9250 15.3 59.5 200 8 4 5.6 3.1 28.4 83.1 -1.2 273 1.4 9000 15.7 60.3 190 7 4 5.4 2.9 28.0 82.5 -1.6 255 1.3 8750 16.1 61.0 180 7 3 6.5 3.6 27.8 82.0 -1.8 234 1.2 8500 16.6 61.9 170 6 3 6.2 3.4 27.5 81.5 -2.1 213 1.1 8250 17.1 62.8 160 6 3 6.3 3.4 27.2 81.0 -2.4 191 1.0 8000 17.5 63.5 155 6 3 6.7 3.7 27.0 80.5 -2.6 170 0.9 7750 18.1 64.6 155 6 3 7.8 4.3 26.8 80.2 -2.8 146 0.7 7500 18.7 65.7 150 6 3 6.5 3.5 26.6 79.9 -3.0 122 0.6 7250 19.0 66.2 150 5 3 4.6 2.5 26.3 79.3 -3.4 103 0.5 7000 19.4 66.9 155 5 2 4.2 2.3 25.9 78.5 -3.8 86 0.4 6750 19.6 67.3 165 4 2 2.7 1.5 25.4 77.7 -4.3 71 0.4 6500 19.7 67.5 180 3 1 -1.7 -0.9 24.7 76.5 -4.9 62 0.3 6250 19.3 66.7 210 1 0 -4.2 -2.3 23.7 74.6 -6.0 64 0.3 6000 19.0 66.2 325 2 1 -3.4 -1.9 22.7 72.8 -7.1 67 0.3 5750 18.6 65.5 335 4 2 -4.2 -2.3 21.7 71.0 -8.2 70 0.4 5500 18.2 64.8 330 4 2 -4.6 -2.5 20.6 69.0 -9.4 77 0.4 * * * * * * Numerical weather prediction model forecast data valid * * * * * * 06/08/2024 at 0900 MDT | 06/08/2024 at 1200 MDT | CAPE... +237.5 LI... -1.6 | CAPE... +1195.3 LI... -3.2 CINH... -322.7 K Index... +27.7 | CINH... -80.4 K Index... +28.6 | 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 -59.7 -75.5 270 19 10 0.4 0.2 | -57.9 -72.2 275 22 11 1.3 0.7 45000 -58.5 -73.3 255 29 15 1.9 1.1 | -56.3 -69.3 260 32 16 0.3 0.2 40000 -55.1 -67.2 255 30 16 7.5 4.1 | -55.4 -67.7 250 30 15 7.3 4.0 38000 -51.0 -59.8 250 34 18 6.9 3.8 | -51.3 -60.3 250 37 19 6.8 3.7 36000 -46.8 -52.2 245 38 20 6.9 3.8 | -47.2 -53.0 250 45 23 6.8 3.7 34000 -41.8 -43.2 245 38 19 7.7 4.2 | -42.3 -44.1 245 46 24 7.5 4.1 32000 -37.1 -34.8 245 36 18 7.6 4.2 | -37.8 -36.0 245 45 23 7.4 4.1 30000 -32.7 -26.9 245 33 17 7.4 4.1 | -33.3 -27.9 245 41 21 7.4 4.1 29000 -30.5 -22.9 245 32 16 7.4 4.1 | -31.1 -24.0 245 38 20 7.4 4.1 28000 -28.2 -18.8 250 30 16 7.4 4.1 | -28.9 -20.0 245 35 18 7.5 4.1 27000 -26.0 -14.8 250 31 16 7.4 4.1 | -26.7 -16.1 250 35 18 7.5 4.1 26000 -23.8 -10.8 255 31 16 7.4 4.1 | -24.4 -11.9 255 35 18 7.5 4.1 25000 -21.6 -6.9 260 32 17 7.4 4.1 | -22.2 -8.0 265 35 18 7.4 4.1 24000 -19.5 -3.1 265 32 17 7.3 4.0 | -19.7 -3.5 265 35 18 8.6 4.7 23000 -17.3 0.9 265 32 17 7.3 4.0 | -17.1 1.2 265 34 18 8.6 4.7 22000 -15.2 4.6 270 32 17 7.3 4.0 | -14.6 5.7 265 34 17 8.6 4.7 21000 -12.8 9.0 270 32 17 8.2 4.5 | -12.2 10.0 265 34 18 7.8 4.3 20000 -10.4 13.3 265 32 16 8.2 4.5 | -9.9 14.2 265 35 18 7.8 4.3 19500 -9.1 15.6 265 32 16 8.2 4.5 | -8.8 16.2 265 36 18 7.8 4.3 19000 -7.9 17.8 265 31 16 8.7 4.8 | -7.7 18.1 265 36 18 7.6 4.2 18500 -6.6 20.1 265 31 16 8.8 4.8 | -6.6 20.1 265 36 18 7.6 4.2 18000 -5.3 22.5 265 31 16 8.8 4.8 | -5.5 22.1 265 36 18 7.7 4.2 17500 -4.1 24.6 265 30 15 8.5 4.7 | -4.3 24.3 265 35 18 8.5 4.7 17000 -2.2 28.0 265 29 15 8.6 4.7 | -2.4 27.7 270 33 17 8.5 4.7 16500 -1.0 30.2 260 27 14 8.9 4.9 | -1.2 29.8 270 31 16 8.7 4.8 16000 0.3 32.5 260 26 13 8.9 4.9 | 0.0 32.0 270 28 15 8.9 4.9 15500 1.5 34.7 255 24 12 7.9 4.4 | 1.2 34.2 270 26 13 7.5 4.1 15000 2.7 36.9 255 22 12 7.9 4.3 | 2.2 36.0 275 24 12 7.5 4.1 14500 3.8 38.8 250 21 11 7.7 4.2 | 3.3 37.9 275 21 11 8.6 4.7 14000 4.9 40.8 250 18 9 7.5 4.1 | 4.7 40.5 275 20 10 9.5 5.2 13500 5.9 42.6 245 15 8 7.3 4.0 | 6.1 43.0 275 18 9 9.4 5.1 13000 6.9 44.4 250 13 7 6.8 3.7 | 7.4 45.3 275 16 8 9.0 4.9 12500 7.9 46.2 250 10 5 6.7 3.7 | 8.7 47.7 275 15 8 8.8 4.9 12000 8.8 47.8 255 8 4 5.9 3.2 | 9.9 49.8 275 14 7 7.3 4.0 11500 9.7 49.5 265 5 3 5.9 3.3 | 11.0 51.8 270 12 6 7.5 4.1 11000 10.5 50.9 265 3 2 5.5 3.0 | 11.9 53.4 270 10 5 5.4 3.0 10500 11.3 52.3 245 2 1 4.6 2.5 | 12.7 54.9 270 8 4 2.9 1.6 10250 11.6 52.9 230 1 1 4.9 2.7 | 12.8 55.0 265 7 4 3.0 1.6 10000 12.1 53.8 180 1 1 7.1 3.9 | 13.3 55.9 260 6 3 6.6 3.6 9750 12.6 54.7 140 2 1 7.4 4.1 | 13.7 56.7 255 5 3 5.7 3.1 9500 13.1 55.6 125 3 1 7.3 4.0 | 14.1 57.4 240 4 2 5.9 3.2 9250 13.6 56.5 120 4 2 6.5 3.6 | 14.5 58.1 225 3 2 4.9 2.7 9000 14.1 57.4 110 4 2 6.7 3.7 | 14.8 58.6 195 3 1 5.7 3.1 8750 14.6 58.3 105 4 2 7.5 4.1 | 15.3 59.5 165 3 1 6.7 3.7 8500 15.2 59.4 095 5 2 6.7 3.7 | 15.7 60.3 140 3 2 6.7 3.7 8250 15.6 60.1 085 5 3 5.2 2.8 | 16.2 61.2 130 4 2 7.7 4.2 8000 15.9 60.6 070 6 3 3.5 1.9 | 16.7 62.1 120 4 2 8.8 4.8 7750 16.1 61.0 055 6 3 2.7 1.5 | 17.3 63.1 120 4 2 9.2 5.1 7500 16.3 61.3 045 7 4 1.4 0.8 | 18.0 64.4 115 4 2 9.5 5.2 7250 16.3 61.3 040 8 4 -0.1 -0.1 | 18.7 65.7 115 4 2 10.1 5.6 7000 16.2 61.2 035 10 5 -0.1 -0.1 | 19.5 67.1 115 4 2 10.2 5.6 6750 16.1 61.0 030 11 5 -1.4 -0.8 | 20.2 68.4 110 4 2 9.4 5.1 6500 16.1 61.0 025 11 6 5.0 2.7 | 20.9 69.6 110 4 2 10.3 5.7 6250 16.8 62.2 025 10 5 11.1 6.1 | 21.8 71.2 110 3 2 11.9 6.5 6000 17.5 63.5 020 8 4 8.5 4.6 | 22.6 72.7 110 3 2 10.6 5.8 5750 18.2 64.8 015 7 4 12.7 7.0 | 23.4 74.1 110 3 2 14.1 7.7 5500 19.5 67.1 015 7 4 23.2 12.7 | 24.9 76.8 110 3 2 25.9 14.2 06/08/2024 at 1500 MDT | 06/08/2024 at 1800 MDT | CAPE... +1725.8 LI... -4.8 | CAPE... +1815.1 LI... -4.8 CINH... -15.4 K Index... +36.1 | CINH... -53.8 K Index... +31.3 | 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 -58.3 -72.9 285 18 9 0.9 0.5 | -59.3 -74.7 290 13 7 1.3 0.7 45000 -57.0 -70.6 270 27 14 0.9 0.5 | -57.4 -71.3 265 14 7 0.9 0.5 40000 -55.1 -67.2 260 37 19 7.5 4.1 | -55.0 -67.0 220 19 10 7.8 4.3 38000 -51.1 -60.0 260 35 18 6.8 3.7 | -50.3 -58.5 220 19 10 7.9 4.3 36000 -47.0 -52.6 265 34 17 6.8 3.7 | -45.6 -50.1 215 19 10 7.9 4.3 34000 -41.9 -43.4 270 33 17 7.7 4.2 | -40.8 -41.4 225 19 10 7.9 4.3 32000 -37.3 -35.1 270 33 17 7.6 4.2 | -36.1 -33.0 245 20 10 7.9 4.4 30000 -32.5 -26.5 265 33 17 8.1 4.4 | -30.9 -23.6 255 23 12 7.7 4.2 29000 -30.1 -22.2 265 33 17 8.1 4.4 | -28.6 -19.5 260 24 13 7.7 4.2 28000 -27.7 -17.9 265 33 17 7.5 4.1 | -26.3 -15.3 265 26 13 7.8 4.3 27000 -25.6 -14.1 265 34 18 6.8 3.7 | -24.0 -11.2 265 27 14 7.8 4.3 26000 -23.6 -10.5 265 35 18 6.8 3.7 | -21.6 -6.9 265 29 15 7.9 4.3 25000 -21.6 -6.9 260 37 19 6.7 3.7 | -19.3 -2.7 265 30 15 7.9 4.3 24000 -19.4 -2.9 260 38 20 7.7 4.2 | -17.2 1.0 265 31 16 7.1 3.9 23000 -17.1 1.2 260 40 21 7.8 4.3 | -15.1 4.8 265 31 16 7.1 3.9 22000 -14.8 5.4 260 41 21 7.9 4.3 | -13.0 8.6 260 32 16 7.1 3.9 21000 -12.4 9.7 260 40 21 8.4 4.6 | -11.0 12.2 260 32 16 7.0 3.9 20000 -10.0 14.0 255 38 20 8.5 4.7 | -8.9 16.0 260 32 16 7.1 3.9 19500 -8.8 16.2 255 37 19 8.6 4.7 | -7.9 17.8 260 32 16 7.1 3.9 19000 -7.6 18.3 255 36 19 8.3 4.5 | -6.9 19.6 260 32 16 7.5 4.1 18500 -6.4 20.5 255 34 17 8.2 4.5 | -5.8 21.6 260 31 16 7.6 4.2 18000 -5.3 22.5 255 31 16 8.3 4.5 | -4.7 23.5 265 30 15 7.6 4.2 17500 -4.0 24.8 255 29 15 8.7 4.8 | -3.6 25.5 265 28 15 7.6 4.2 17000 -2.2 28.0 255 26 13 8.6 4.7 | -2.0 28.4 265 26 13 7.6 4.2 16500 -1.0 30.2 255 24 12 8.2 4.5 | -0.9 30.4 265 24 12 7.5 4.1 16000 0.2 32.4 255 22 11 8.2 4.5 | 0.2 32.4 265 22 12 7.6 4.2 15500 1.4 34.5 255 21 11 8.5 4.7 | 1.2 34.2 265 21 11 6.9 3.8 15000 2.7 36.9 250 19 10 8.6 4.7 | 2.2 36.0 265 19 10 6.9 3.8 14500 4.0 39.2 250 17 9 8.9 4.9 | 3.2 37.8 265 18 9 7.4 4.1 14000 5.3 41.5 250 16 8 9.1 5.0 | 4.4 39.9 270 16 8 8.0 4.4 13500 6.7 44.1 245 14 7 8.8 4.8 | 5.5 41.9 270 15 8 7.9 4.4 13000 7.9 46.2 245 12 6 8.1 4.4 | 6.6 43.9 270 13 7 7.7 4.2 12500 9.1 48.4 240 11 6 8.1 4.4 | 7.8 46.0 275 12 6 7.7 4.2 12000 10.2 50.4 235 8 4 7.8 4.3 | 8.9 48.0 285 10 5 8.0 4.4 11500 11.4 52.5 220 6 3 7.9 4.3 | 10.0 50.0 295 9 5 8.1 4.5 11000 12.3 54.1 195 4 2 5.9 3.2 | 11.0 51.8 305 9 4 6.5 3.5 10500 13.1 55.6 165 4 2 9.1 5.0 | 11.9 53.4 310 8 4 8.8 4.8 10250 13.9 57.0 145 4 2 10.9 6.0 | 12.7 54.9 320 8 4 9.2 5.1 10000 14.5 58.1 145 3 2 8.1 4.4 | 13.1 55.6 320 8 4 6.6 3.6 9750 15.1 59.2 140 3 2 8.9 4.9 | 13.6 56.5 325 8 4 7.3 4.0 9500 15.8 60.4 140 3 2 8.6 4.7 | 14.1 57.4 330 8 4 7.2 4.0 9250 16.4 61.5 140 3 2 9.2 5.0 | 14.6 58.3 335 8 4 6.8 3.7 9000 17.1 62.8 135 3 2 9.8 5.4 | 15.1 59.2 335 8 4 6.3 3.4 8750 17.8 64.0 135 3 2 9.8 5.4 | 15.5 59.9 340 7 4 6.4 3.5 8500 18.6 65.5 135 3 1 9.9 5.4 | 15.9 60.6 345 7 4 6.4 3.5 8250 19.3 66.7 135 3 1 10.4 5.7 | 16.4 61.5 350 7 4 6.3 3.4 8000 20.1 68.2 135 3 1 10.2 5.6 | 16.7 62.1 005 7 4 5.8 3.2 7750 20.8 69.4 130 3 1 9.6 5.3 | 17.1 62.8 010 8 4 5.2 2.9 7500 21.5 70.7 130 2 1 10.0 5.5 | 17.5 63.5 020 8 4 5.6 3.1 7250 22.3 72.1 130 2 1 10.6 5.8 | 17.9 64.2 025 9 5 6.8 3.8 7000 23.1 73.6 130 2 1 10.6 5.8 | 18.3 64.9 035 10 5 7.1 3.9 6750 23.9 75.0 130 2 1 9.6 5.3 | 18.8 65.8 040 10 5 4.8 2.6 6500 24.6 76.3 125 2 1 10.1 5.6 | 19.1 66.4 040 10 5 5.8 3.2 6250 25.4 77.7 125 2 1 11.3 6.2 | 19.6 67.3 045 9 5 8.3 4.6 6000 26.2 79.2 125 2 1 10.8 5.9 | 20.1 68.2 045 8 4 8.0 4.4 5750 27.0 80.6 125 2 1 12.0 6.6 | 20.7 69.3 050 7 4 7.2 4.0 5500 28.2 82.8 120 2 1 21.2 11.6 | 21.2 70.2 055 6 3 10.6 5.8 ________________________________________________________________________________ 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