Soaring Guidance
Issued by NWS Denver/Boulder, CO
Issued by NWS Denver/Boulder, CO
180 UXUS97 KBOU 201235 SRGBOU Soaring Forecast National Weather Service Denver/Boulder, Colorado 0635 MDT Thursday, June 20, 2024 This forecast is for Thursday, June 20, 2024: If the trigger temperature of 77.0 F/25.0 C is reached...then Thermal Soaring Index....................... Excellent Maximum rate of lift........................ 1218 ft/min (6.2 m/s) Maximum height of thermals.................. 17078 ft MSL (11780 ft AGL) Forecast maximum temperature................... 89.0 F/32.1 C Time of trigger temperature.................... 0945 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................. 12606 ft MSL (7308 ft AGL) Thermal soaring outlook for Friday 06/21....... 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....................... 14404 ft MSL (9106 ft AGL) Wave soaring outlook for Friday 06/21.......... Poor Remarks... Sunrise/Sunset.................... 05:31:34 / 20:30:56 MDT Total possible sunshine........... 14 hr 59 min 22 sec (899 min 22 sec) Altitude of sun at 13:01:15 MDT... 73.67 degrees Upper air data from numerical model forecast valid on 06/20/2024 at 0600 MDT Freezing level.................. 15540 ft MSL (10242 ft AGL) Convective condensation level... 13100 ft MSL (7802 ft AGL) Lifted condensation level....... 14281 ft MSL (8983 ft AGL) Lifted index.................... -5.8 K index......................... +27.0 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 -61.0 -77.8 230 63 32 0.7 0.4 M M M M M 45000 -58.1 -72.6 235 83 43 4.5 2.5 M M M M M 40000 -51.2 -60.2 235 68 35 5.1 2.8 M M M M M 38000 -48.1 -54.6 230 58 30 5.1 2.8 M M M M M 36000 -45.1 -49.2 230 47 24 4.9 2.7 M M M M M 34000 -40.7 -41.3 220 43 22 7.7 4.2 M M M M M 32000 -35.5 -31.9 210 40 21 7.9 4.3 M M M M M 30000 -31.0 -23.8 215 39 20 7.6 4.2 44.8 112.7 10.0 M M 29000 -28.7 -19.7 220 39 20 7.6 4.2 44.0 111.3 9.5 M M 28000 -26.4 -15.5 220 38 20 7.5 4.1 43.3 110.0 9.1 M M 27000 -24.2 -11.6 230 38 20 7.5 4.1 42.3 108.2 8.4 M M 26000 -21.9 -7.4 235 38 20 7.5 4.1 41.5 106.7 7.8 M M 25000 -19.7 -3.5 240 39 20 7.4 4.1 40.8 105.4 7.3 M M 24000 -17.6 0.3 245 40 20 6.8 3.7 39.6 103.3 6.5 M M 23000 -15.6 3.9 245 40 21 6.9 3.8 38.5 101.4 5.6 M M 22000 -13.6 7.5 245 41 21 6.8 3.7 37.6 99.7 4.9 M M 21000 -11.6 11.1 245 37 19 6.7 3.7 36.4 97.6 3.9 M M 20000 -9.7 14.5 250 34 17 6.8 3.7 35.4 95.7 3.0 M M 19500 -8.7 16.3 250 32 16 6.9 3.8 34.9 94.8 2.5 M M 19000 -7.7 18.1 250 29 15 6.7 3.7 34.4 93.9 2.0 M M 18500 -6.8 19.8 255 26 13 6.8 3.7 33.9 93.0 1.5 M M 18000 -5.8 21.6 255 22 11 6.8 3.8 33.4 92.1 1.0 M M 17500 -4.9 23.2 255 19 10 6.9 3.8 32.9 91.2 0.5 M M 17000 -3.9 25.0 260 17 9 6.9 3.8 32.4 90.3 0.0 M M 16500 -2.8 27.0 260 15 8 8.7 4.8 32.1 89.7 -0.3 974 4.9 16000 -0.9 30.4 250 14 7 8.6 4.7 31.8 89.2 -0.6 894 4.5 15500 0.4 32.7 245 14 7 8.4 4.6 31.6 88.8 -0.8 842 4.3 15000 1.6 34.9 240 15 8 8.5 4.7 31.3 88.4 -1.0 790 4.0 14500 2.8 37.0 235 15 8 7.6 4.2 31.1 87.9 -1.3 739 3.8 14000 3.9 39.0 230 16 8 7.5 4.1 30.7 87.2 -1.7 693 3.5 13500 4.9 40.8 225 17 9 7.1 3.9 30.3 86.6 -2.2 647 3.3 13000 5.9 42.6 220 19 10 6.9 3.8 29.8 85.7 -2.7 603 3.1 12500 6.8 44.2 215 21 11 6.9 3.8 29.4 84.9 -3.2 559 2.8 12000 7.8 46.0 215 23 12 7.0 3.9 28.9 84.1 -3.7 515 2.6 11500 8.8 47.8 215 25 13 7.1 3.9 28.5 83.3 -4.2 471 2.4 11000 9.8 49.6 215 25 13 7.0 3.8 28.1 82.6 -4.6 426 2.2 10500 10.9 51.6 215 25 13 4.1 2.3 27.7 81.8 -5.1 380 1.9 10250 11.0 51.8 215 26 13 3.6 2.0 27.1 80.8 -5.6 367 1.9 10000 11.5 52.7 215 26 13 8.6 4.7 26.9 80.4 -5.9 345 1.8 9750 12.2 54.0 215 26 13 9.6 5.3 26.8 80.2 -6.0 319 1.6 9500 12.8 55.0 220 26 13 7.1 3.9 26.8 80.2 -6.1 292 1.5 9250 13.1 55.6 220 26 13 3.7 2.0 26.4 79.5 -6.5 274 1.4 9000 13.4 56.1 220 26 13 4.6 2.5 25.9 78.7 -7.0 259 1.3 8750 13.8 56.8 220 25 13 5.8 3.2 25.6 78.0 -7.4 241 1.2 8500 14.1 57.4 220 25 13 4.0 2.2 25.2 77.4 -7.8 223 1.1 8250 14.3 57.7 215 25 13 2.4 1.3 24.7 76.4 -8.3 210 1.1 8000 14.5 58.1 215 25 13 3.0 1.6 24.2 75.5 -8.9 198 1.0 7750 14.6 58.3 210 25 13 3.3 1.8 23.6 74.6 -9.5 185 0.9 7500 14.9 58.8 210 25 13 4.2 2.3 23.2 73.7 -10.0 170 0.9 7250 15.2 59.4 205 25 13 4.6 2.6 22.8 73.0 -10.4 153 0.8 7000 15.5 59.9 200 25 13 4.4 2.4 22.4 72.3 -10.8 136 0.7 6750 15.8 60.4 195 25 13 3.6 2.0 22.0 71.5 -11.3 120 0.6 6500 16.0 60.8 190 24 12 3.0 1.6 21.4 70.6 -11.8 106 0.5 6250 16.2 61.2 190 22 11 3.5 1.9 21.0 69.7 -12.4 93 0.5 6000 16.4 61.5 185 19 10 2.6 1.4 20.5 68.8 -13.0 80 0.4 5750 16.5 61.7 180 16 8 1.1 0.6 19.9 67.8 -13.7 70 0.4 5500 16.5 61.7 180 11 5 1.1 0.6 19.2 66.6 -14.4 62 0.3 * * * * * * Numerical weather prediction model forecast data valid * * * * * * 06/20/2024 at 0900 MDT | 06/20/2024 at 1200 MDT | CAPE... +1007.1 LI... -4.1 | CAPE... +1058.3 LI... -5.0 CINH... -106.2 K Index... +28.1 | CINH... -43.1 K Index... +23.8 | 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 -61.3 -78.3 230 66 34 1.5 0.8 | -61.9 -79.4 235 71 36 1.3 0.7 45000 -57.7 -71.9 235 83 43 4.2 2.3 | -58.1 -72.6 240 85 44 4.9 2.7 40000 -51.0 -59.8 230 70 36 6.3 3.5 | -50.4 -58.7 235 70 36 6.6 3.6 38000 -47.2 -53.0 230 62 32 6.3 3.5 | -46.5 -51.7 235 64 33 6.6 3.6 36000 -43.4 -46.1 235 53 27 6.3 3.5 | -42.5 -44.5 235 58 30 6.7 3.7 34000 -39.4 -38.9 230 47 24 6.7 3.7 | -38.2 -36.8 230 51 26 6.2 3.4 32000 -34.9 -30.8 225 40 21 6.8 3.7 | -34.5 -30.1 225 46 24 6.3 3.5 30000 -31.1 -24.0 225 38 19 6.4 3.5 | -30.9 -23.6 230 42 22 6.1 3.4 29000 -29.1 -20.4 230 37 19 6.5 3.5 | -29.1 -20.4 230 40 21 6.2 3.4 28000 -27.2 -17.0 230 36 19 6.8 3.7 | -27.2 -17.0 230 39 20 7.5 4.1 27000 -25.1 -13.2 235 36 18 6.9 3.8 | -24.9 -12.8 230 36 19 7.7 4.2 26000 -23.1 -9.6 235 35 18 6.9 3.8 | -22.6 -8.7 230 34 17 7.8 4.3 25000 -21.0 -5.8 240 35 18 7.1 3.9 | -20.3 -4.5 230 31 16 7.7 4.2 24000 -18.8 -1.8 240 34 18 7.7 4.2 | -18.2 -0.8 225 30 16 7.2 4.0 23000 -16.5 2.3 240 33 17 7.8 4.3 | -16.0 3.2 225 29 15 7.3 4.0 22000 -14.2 6.4 240 31 16 7.6 4.2 | -13.9 7.0 225 28 15 7.0 3.9 21000 -12.1 10.2 235 29 15 7.5 4.1 | -11.9 10.6 220 27 14 6.7 3.7 20000 -9.9 14.2 235 27 14 7.6 4.2 | -10.0 14.0 215 26 14 6.7 3.7 19500 -8.9 16.0 230 26 13 7.7 4.2 | -9.0 15.8 215 26 13 6.6 3.6 19000 -7.7 18.1 235 26 13 7.6 4.2 | -7.8 18.0 215 26 13 8.5 4.6 18500 -6.5 20.3 235 26 13 7.7 4.2 | -6.6 20.1 215 25 13 8.3 4.6 18000 -5.4 22.3 240 26 14 8.0 4.4 | -5.4 22.3 215 25 13 8.6 4.7 17500 -4.1 24.6 240 24 12 8.3 4.5 | -3.4 25.9 215 24 12 8.8 4.9 17000 -2.9 26.8 240 22 11 8.3 4.6 | -2.1 28.2 215 23 12 8.7 4.8 16500 -1.8 28.8 240 19 10 7.5 4.1 | -0.8 30.6 215 23 12 8.7 4.8 16000 -0.2 31.6 250 15 8 7.6 4.2 | 0.5 32.9 215 23 12 8.7 4.7 15500 0.9 33.6 245 12 6 7.5 4.1 | 1.7 35.1 215 23 12 8.5 4.7 15000 2.0 35.6 230 10 5 7.5 4.1 | 3.0 37.4 215 22 11 8.5 4.7 14500 3.1 37.6 215 9 5 8.5 4.7 | 4.2 39.6 215 21 11 8.0 4.4 14000 4.4 39.9 215 9 5 8.5 4.7 | 5.4 41.7 215 18 9 8.0 4.4 13500 5.7 42.3 215 9 5 8.7 4.8 | 6.6 43.9 210 15 8 8.1 4.4 13000 6.9 44.4 220 9 5 8.7 4.8 | 7.8 46.0 210 14 7 8.1 4.4 12500 8.2 46.8 225 10 5 8.4 4.6 | 9.0 48.2 205 13 7 8.3 4.5 12000 9.3 48.7 225 11 6 8.0 4.4 | 10.2 50.4 210 12 6 8.4 4.6 11500 10.5 50.9 230 12 6 7.0 3.9 | 11.4 52.5 210 10 5 8.4 4.6 11000 11.3 52.3 230 14 7 5.8 3.2 | 12.6 54.7 215 9 5 8.2 4.5 10500 12.1 53.8 230 15 8 3.0 1.6 | 13.8 56.8 215 8 4 4.1 2.3 10250 12.2 54.0 230 15 8 3.4 1.9 | 14.0 57.2 215 8 4 5.4 3.0 10000 12.7 54.9 230 17 9 8.3 4.6 | 14.7 58.5 220 8 4 11.6 6.3 9750 13.3 55.9 225 18 9 8.9 4.9 | 15.5 59.9 225 7 4 10.6 5.8 9500 13.9 57.0 225 20 10 6.0 3.3 | 16.2 61.2 230 7 4 8.5 4.7 9250 14.1 57.4 225 21 11 2.9 1.6 | 16.7 62.1 230 8 4 5.6 3.1 9000 14.4 57.9 225 22 11 4.7 2.6 | 17.1 62.8 225 8 4 6.2 3.4 8750 14.7 58.5 220 24 12 5.5 3.0 | 17.5 63.5 220 10 5 6.2 3.4 8500 15.1 59.2 220 25 13 3.3 1.8 | 17.8 64.0 215 11 5 5.4 3.0 8250 15.2 59.4 220 25 13 2.1 1.1 | 18.0 64.4 210 11 6 4.3 2.4 8000 15.3 59.5 220 25 13 1.6 0.9 | 18.3 64.9 200 12 6 5.8 3.2 7750 15.3 59.5 215 24 13 1.5 0.8 | 18.7 65.7 195 12 6 7.7 4.2 7500 15.5 59.9 210 23 12 4.6 2.5 | 19.3 66.7 195 12 6 9.4 5.2 7250 15.8 60.4 200 22 11 6.2 3.4 | 20.0 68.0 195 11 6 10.4 5.7 7000 16.2 61.2 195 21 11 5.3 2.9 | 20.8 69.4 195 11 6 9.8 5.4 6750 16.5 61.7 185 20 10 7.9 4.3 | 21.5 70.7 195 11 6 9.7 5.3 6500 17.2 63.0 180 20 10 10.8 5.9 | 22.3 72.1 195 11 6 10.4 5.7 6250 18.0 64.4 180 19 10 10.6 5.8 | 23.0 73.4 190 11 5 10.8 5.9 6000 18.8 65.8 180 19 10 10.5 5.7 | 23.8 74.8 190 10 5 10.3 5.7 5750 19.7 67.5 180 18 9 14.9 8.2 | 24.7 76.5 190 10 5 13.6 7.4 5500 21.1 70.0 175 16 8 22.8 12.5 | 25.9 78.6 190 9 5 20.0 11.0 06/20/2024 at 1500 MDT | 06/20/2024 at 1800 MDT | CAPE... +1308.0 LI... -4.7 | CAPE... +794.1 LI... -3.8 CINH... -5.2 K Index... +28.8 | CINH... -62.8 K Index... +36.2 | 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 -63.2 -81.8 235 73 38 1.8 1.0 | -62.9 -81.2 240 63 32 2.2 1.2 45000 -58.5 -73.3 240 84 43 5.6 3.1 | -57.7 -71.9 245 75 39 5.9 3.3 40000 -50.0 -58.0 235 73 38 6.4 3.5 | -48.5 -55.3 245 75 39 5.1 2.8 38000 -46.1 -51.0 235 65 34 6.4 3.5 | -45.5 -49.9 245 65 34 5.1 2.8 36000 -41.8 -43.2 235 57 29 6.5 3.5 | -42.4 -44.3 250 55 28 6.0 3.3 34000 -37.9 -36.2 235 51 26 6.5 3.6 | -37.6 -35.7 250 50 26 8.1 4.4 32000 -33.9 -29.0 235 46 24 6.7 3.7 | -32.8 -27.0 250 45 23 8.1 4.5 30000 -29.8 -21.6 235 40 21 6.9 3.8 | -28.7 -19.7 245 42 22 6.6 3.6 29000 -27.8 -18.0 235 37 19 6.9 3.8 | -26.3 -15.3 240 40 21 6.6 3.6 28000 -25.7 -14.3 230 35 18 7.1 3.9 | -24.3 -11.7 235 39 20 7.0 3.9 27000 -23.6 -10.5 230 35 18 7.1 3.9 | -22.2 -8.0 235 38 19 7.0 3.8 26000 -21.5 -6.7 230 34 18 7.1 3.9 | -20.1 -4.2 230 37 19 7.0 3.8 25000 -19.3 -2.7 230 34 18 7.2 3.9 | -18.1 -0.6 225 36 19 7.6 4.2 24000 -17.2 1.0 225 32 17 7.4 4.0 | -15.7 3.7 220 33 17 8.1 4.5 23000 -15.0 5.0 225 30 16 7.4 4.1 | -13.3 8.1 210 30 15 8.2 4.5 22000 -12.8 9.0 225 28 15 7.4 4.1 | -11.0 12.2 205 28 14 6.9 3.8 21000 -10.7 12.7 225 29 15 7.3 4.0 | -9.3 15.3 200 28 15 6.0 3.3 20000 -8.6 16.5 225 30 15 7.4 4.0 | -7.6 18.3 200 29 15 6.1 3.3 19500 -7.5 18.5 225 30 15 7.2 4.0 | -6.7 19.9 200 29 15 6.1 3.3 19000 -6.3 20.7 225 31 16 9.1 5.0 | -5.9 21.4 200 29 15 5.9 3.3 18500 -4.3 24.3 220 32 16 9.0 4.9 | -5.0 23.0 200 27 14 6.0 3.3 18000 -3.1 26.4 220 32 16 8.0 4.4 | -4.2 24.4 195 26 13 5.9 3.2 17500 -1.9 28.6 225 32 16 8.1 4.4 | -3.3 26.1 190 25 13 5.9 3.2 17000 -0.7 30.7 225 31 16 7.9 4.3 | -2.5 27.5 190 24 12 5.9 3.3 16500 0.4 32.7 225 30 15 7.7 4.2 | -1.5 29.3 185 23 12 7.3 4.0 16000 1.6 34.9 230 28 14 7.7 4.2 | -0.5 31.1 185 22 11 7.2 3.9 15500 2.7 36.9 230 26 13 7.4 4.1 | 0.5 32.9 180 20 11 7.3 4.0 15000 3.7 38.7 230 24 12 7.5 4.1 | 1.5 34.7 180 20 10 7.4 4.1 14500 4.8 40.6 230 22 11 7.6 4.2 | 2.6 36.7 180 19 10 7.8 4.3 14000 5.9 42.6 225 20 10 7.6 4.2 | 3.8 38.8 180 18 9 8.4 4.6 13500 7.0 44.6 225 17 9 7.3 4.0 | 5.0 41.0 175 17 9 8.6 4.7 13000 8.0 46.4 215 15 8 7.2 3.9 | 7.0 44.6 180 16 8 9.5 5.2 12500 9.1 48.4 205 14 7 7.6 4.1 | 8.3 46.9 180 16 8 9.0 4.9 12000 10.2 50.4 200 13 7 8.0 4.4 | 9.6 49.3 185 17 9 8.6 4.7 11500 11.3 52.3 195 12 6 8.3 4.5 | 10.9 51.6 185 18 9 8.1 4.5 11000 12.5 54.5 185 12 6 8.6 4.7 | 12.0 53.6 180 19 10 7.4 4.1 10500 13.6 56.5 175 14 7 4.5 2.5 | 13.1 55.6 180 20 10 3.7 2.0 10250 13.7 56.7 170 14 7 6.3 3.5 | 13.2 55.8 180 20 10 5.6 3.1 10000 14.6 58.3 170 14 7 13.4 7.3 | 14.0 57.2 175 19 10 11.7 6.4 9750 15.5 59.9 170 14 7 12.1 6.6 | 14.7 58.5 175 19 10 10.9 6.0 9500 16.3 61.3 170 14 7 10.1 5.6 | 15.5 59.9 175 18 9 8.1 4.4 9250 16.9 62.4 170 14 7 7.7 4.2 | 15.9 60.6 175 18 9 5.6 3.1 9000 17.6 63.7 170 15 8 10.1 5.5 | 16.5 61.7 175 17 9 9.6 5.3 8750 18.4 65.1 170 15 8 10.9 6.0 | 17.3 63.1 175 16 8 11.2 6.1 8500 19.2 66.6 170 15 8 10.6 5.8 | 18.0 64.4 175 16 8 8.4 4.6 8250 20.0 68.0 165 15 8 10.9 6.0 | 18.5 65.3 180 14 7 6.2 3.4 8000 20.8 69.4 165 16 8 10.1 5.6 | 19.0 66.2 180 13 7 7.4 4.1 7750 21.5 70.7 165 16 8 9.3 5.1 | 19.6 67.3 185 12 6 7.7 4.2 7500 22.2 72.0 165 16 8 10.0 5.5 | 20.1 68.2 190 11 6 6.7 3.7 7250 22.9 73.2 165 16 8 10.6 5.8 | 20.6 69.1 195 10 5 6.0 3.3 7000 23.7 74.7 165 16 8 10.0 5.5 | 21.0 69.8 205 9 4 6.7 3.7 6750 24.4 75.9 165 16 8 9.4 5.2 | 21.6 70.9 215 8 4 7.9 4.4 6500 25.2 77.4 165 16 8 10.5 5.7 | 22.2 72.0 225 8 4 8.2 4.5 6250 26.0 78.8 165 16 8 11.9 6.6 | 22.8 73.0 235 8 4 7.9 4.3 6000 26.8 80.2 165 16 8 9.3 5.1 | 23.3 73.9 245 8 4 7.9 4.3 5750 27.6 81.7 165 15 8 14.3 7.8 | 24.0 75.2 250 8 4 11.3 6.2 5500 29.3 84.7 160 15 8 30.9 17.0 | 25.0 77.0 250 8 4 17.0 9.3 ________________________________________________________________________________ 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