Soaring Guidance
Issued by NWS Denver/Boulder, CO
Issued by NWS Denver/Boulder, CO
090 UXUS97 KBOU 050005 SRGBOU Soaring Forecast National Weather Service Denver/Boulder, Colorado 1804 MDT Thursday, July 4, 2024 This forecast is for Friday, July 5, 2024: If the trigger temperature of 69.8 F/21.0 C is reached...then Thermal Soaring Index....................... Excellent Maximum rate of lift........................ 905 ft/min (4.6 m/s) Maximum height of thermals.................. 16273 ft MSL (10983 ft AGL) Forecast maximum temperature................... 83.0 F/28.8 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................. 11996 ft MSL (6706 ft AGL) Thermal soaring outlook for Saturday 07/06..... 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....................... 46130 ft MSL (40840 ft AGL) Wave soaring outlook for Saturday 07/06........ Poor Remarks... Sunrise/Sunset.................... 05:37:48 / 20:30:40 MDT Total possible sunshine........... 14 hr 52 min 52 sec (892 min 52 sec) Altitude of sun at 13:04:14 MDT... 72.89 degrees Upper air data from numerical model forecast valid on 07/05/2024 at 0600 MDT Freezing level.................. 14213 ft MSL (8923 ft AGL) Convective condensation level... 14686 ft MSL (9396 ft AGL) Lifted condensation level....... 15302 ft MSL (10012 ft AGL) Lifted index.................... -2.2 K index......................... +12.3 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 -60.4 -76.7 290 43 22 1.7 0.9 M M M M M 45000 -56.1 -69.0 285 58 30 4.9 2.7 M M M M M 40000 -48.7 -55.7 285 62 32 5.0 2.8 M M M M M 38000 -45.7 -50.3 285 61 31 5.0 2.8 M M M M M 36000 -42.7 -44.9 285 60 31 5.0 2.8 M M M M M 34000 -39.5 -39.1 290 58 30 5.3 2.9 M M M M M 32000 -36.3 -33.3 290 56 29 5.4 2.9 M M M M M 30000 -31.7 -25.1 295 53 27 7.4 4.1 44.8 112.6 12.5 M M 29000 -29.5 -21.1 295 52 27 7.4 4.1 43.9 111.0 12.0 M M 28000 -27.3 -17.1 300 50 26 7.1 3.9 43.2 109.7 11.5 M M 27000 -25.3 -13.5 300 48 25 6.4 3.5 41.8 107.2 10.6 M M 26000 -23.4 -10.1 300 46 24 6.4 3.5 40.5 104.9 9.7 M M 25000 -21.5 -6.7 295 44 23 6.6 3.6 39.3 102.8 8.9 M M 24000 -20.2 -4.4 300 42 21 3.6 2.0 37.3 99.2 7.3 M M 23000 -19.1 -2.4 300 39 20 3.6 2.0 35.0 95.1 5.5 M M 22000 -18.0 -0.4 300 37 19 3.5 1.9 32.9 91.2 3.8 M M 21000 -16.1 3.0 300 35 18 7.3 4.0 31.7 89.1 2.8 M M 20000 -13.9 7.0 300 33 17 7.3 4.0 30.8 87.5 2.1 M M 19500 -12.8 9.0 300 33 17 7.3 4.0 30.4 86.8 1.8 M M 19000 -11.7 10.9 300 32 16 7.6 4.2 30.1 86.1 1.4 M M 18500 -10.6 12.9 300 32 16 7.7 4.3 29.7 85.5 1.1 M M 18000 -9.4 15.1 300 32 16 7.9 4.4 29.4 84.9 0.8 M M 17500 -8.2 17.2 295 32 17 8.7 4.8 29.1 84.4 0.6 M M 17000 -6.9 19.6 295 33 17 8.8 4.8 29.0 84.1 0.4 M M 16500 -5.6 21.9 295 33 17 8.0 4.4 28.7 83.7 0.2 M M 16000 -4.5 23.9 295 32 17 8.0 4.4 28.4 83.2 -0.1 889 4.5 15500 -2.8 27.0 290 31 16 8.0 4.4 28.0 82.4 -0.6 815 4.1 15000 -1.6 29.1 290 30 15 8.1 4.4 27.7 81.8 -0.9 766 3.9 14500 -0.5 31.1 285 28 14 8.6 4.7 27.5 81.4 -1.2 716 3.6 14000 0.8 33.4 285 26 13 8.7 4.7 27.3 81.1 -1.4 663 3.4 13500 2.1 35.8 285 23 12 8.0 4.4 27.1 80.8 -1.6 610 3.1 13000 3.2 37.8 290 21 11 7.5 4.1 26.7 80.1 -2.0 564 2.9 12500 4.2 39.6 290 19 10 6.6 3.6 26.4 79.5 -2.4 517 2.6 12000 5.0 41.0 295 17 9 5.5 3.0 25.7 78.2 -3.1 478 2.4 11500 5.8 42.4 295 16 8 5.4 3.0 25.0 77.0 -3.8 440 2.2 11000 6.5 43.7 300 14 7 5.3 2.9 24.3 75.7 -4.5 403 2.0 10500 7.3 45.1 310 13 7 3.7 2.0 23.6 74.5 -5.3 366 1.9 10250 7.4 45.3 310 13 7 2.3 1.3 23.0 73.4 -5.9 354 1.8 10000 7.7 45.9 315 13 7 6.4 3.5 22.6 72.7 -6.3 338 1.7 9750 8.2 46.8 320 13 7 8.9 4.9 22.4 72.4 -6.5 315 1.6 9500 8.8 47.8 320 14 7 6.4 3.5 22.3 72.2 -6.7 291 1.5 9250 9.1 48.4 325 14 7 3.9 2.1 21.9 71.5 -7.2 274 1.4 9000 9.4 48.9 325 15 8 5.9 3.3 21.5 70.7 -7.6 257 1.3 8750 9.9 49.8 330 15 8 7.8 4.3 21.3 70.4 -7.8 235 1.2 8500 10.4 50.7 335 16 8 6.2 3.4 21.1 70.0 -8.1 212 1.1 8250 10.8 51.4 335 17 9 4.9 2.7 20.8 69.4 -8.4 193 1.0 8000 11.2 52.2 335 17 9 5.9 3.2 20.4 68.8 -8.8 174 0.9 7750 11.6 52.9 340 18 9 5.6 3.1 20.2 68.3 -9.1 154 0.8 7500 12.0 53.6 340 18 9 2.9 1.6 19.7 67.5 -9.6 137 0.7 7250 12.1 53.8 345 19 10 1.8 1.0 19.1 66.5 -10.1 124 0.6 7000 12.3 54.1 350 19 10 2.2 1.2 18.6 65.4 -10.7 112 0.6 6750 12.4 54.3 355 19 10 1.7 0.9 18.0 64.4 -11.3 100 0.5 6500 12.6 54.7 355 20 10 1.2 0.7 17.3 63.2 -12.0 90 0.5 6250 12.7 54.9 350 21 11 1.4 0.8 16.7 62.0 -12.6 79 0.4 6000 12.8 55.0 350 22 11 1.2 0.7 16.1 60.9 -13.3 68 0.3 5750 13.0 55.4 345 19 10 3.6 2.0 15.5 59.9 -13.9 55 0.3 5500 13.4 56.1 335 14 7 7.7 4.2 15.2 59.3 -14.2 35 0.2 * * * * * * Numerical weather prediction model forecast data valid * * * * * * 07/05/2024 at 0900 MDT | 07/05/2024 at 1200 MDT | CAPE... 0.0 LI... +0.9 | CAPE... +94.7 LI... -0.3 CINH... -0.1 K Index... +6.0 | CINH... -29.6 K Index... +11.6 | 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 -59.3 -74.7 295 40 21 1.8 1.0 | -59.1 -74.4 295 36 18 2.3 1.3 45000 -55.3 -67.5 295 57 29 4.5 2.5 | -54.5 -66.1 295 53 27 4.3 2.4 40000 -48.5 -55.3 285 62 32 4.4 2.4 | -48.1 -54.6 290 59 30 3.5 1.9 38000 -45.8 -50.4 285 61 31 4.4 2.4 | -46.0 -50.8 290 57 29 3.6 2.0 36000 -43.2 -45.8 285 60 31 4.4 2.4 | -43.8 -46.8 290 55 28 3.6 2.0 34000 -40.4 -40.7 290 57 29 4.8 2.6 | -41.2 -42.2 290 52 27 4.8 2.6 32000 -37.5 -35.5 290 54 28 4.8 2.6 | -38.0 -36.4 295 48 25 4.8 2.6 30000 -32.9 -27.2 295 52 27 7.7 4.2 | -33.8 -28.8 300 47 24 7.6 4.2 29000 -30.6 -23.1 300 52 27 7.7 4.2 | -31.5 -24.7 300 46 24 7.6 4.2 28000 -28.3 -18.9 300 52 27 7.5 4.1 | -29.3 -20.7 300 46 24 7.6 4.2 27000 -26.2 -15.2 300 51 26 7.0 3.8 | -27.0 -16.6 300 46 24 7.4 4.0 26000 -24.1 -11.4 300 50 26 7.0 3.8 | -24.8 -12.6 305 46 23 7.4 4.0 25000 -22.0 -7.6 300 49 25 7.2 3.9 | -22.6 -8.7 305 45 23 7.5 4.1 24000 -20.5 -4.9 305 46 24 4.4 2.4 | -20.8 -5.4 305 43 22 5.6 3.1 23000 -19.1 -2.4 305 43 22 4.4 2.4 | -19.1 -2.4 310 40 21 5.6 3.1 22000 -17.8 -0.0 305 40 21 4.1 2.3 | -17.5 0.5 310 37 19 5.4 3.0 21000 -16.0 3.2 305 38 20 6.8 3.8 | -15.5 4.1 310 35 18 6.7 3.7 20000 -13.9 7.0 300 37 19 6.8 3.7 | -13.6 7.5 305 33 17 6.7 3.7 19500 -12.9 8.8 300 36 18 6.8 3.7 | -12.6 9.3 305 32 17 6.7 3.7 19000 -11.9 10.6 300 35 18 7.6 4.1 | -11.6 11.1 305 32 16 6.6 3.6 18500 -10.7 12.7 300 34 17 7.8 4.3 | -10.6 12.9 300 31 16 6.5 3.6 18000 -9.5 14.9 300 33 17 7.8 4.3 | -9.7 14.5 300 31 16 6.5 3.6 17500 -8.4 16.9 295 31 16 7.5 4.1 | -8.7 16.3 300 30 16 6.7 3.7 17000 -7.3 18.9 295 30 16 7.6 4.2 | -7.2 19.0 295 29 15 6.7 3.7 16500 -5.7 21.7 295 28 15 6.9 3.8 | -6.2 20.8 295 28 15 6.9 3.8 16000 -4.7 23.5 295 27 14 6.9 3.8 | -5.2 22.6 295 27 14 6.9 3.8 15500 -3.7 25.3 295 25 13 6.7 3.7 | -4.2 24.4 295 26 13 6.8 3.7 15000 -2.7 27.1 295 24 12 6.8 3.7 | -3.2 26.2 295 24 13 6.8 3.7 14500 -1.7 28.9 290 22 11 7.2 3.9 | -2.2 28.0 295 23 12 7.4 4.1 14000 -0.7 30.7 290 20 10 7.3 4.0 | -1.1 30.0 295 21 11 7.6 4.2 13500 0.4 32.7 290 19 10 7.2 4.0 | -0.0 32.0 295 20 10 7.7 4.2 13000 1.3 34.3 290 17 9 7.1 3.9 | 1.1 34.0 300 18 9 7.8 4.3 12500 2.3 36.1 290 15 8 6.4 3.5 | 2.2 36.0 300 16 8 7.2 3.9 12000 3.1 37.6 295 14 7 5.4 2.9 | 3.1 37.6 305 14 7 6.3 3.5 11500 3.8 38.8 300 12 6 5.0 2.7 | 4.0 39.2 310 12 6 5.9 3.2 11000 4.3 39.7 315 10 5 4.2 2.3 | 4.6 40.3 325 9 5 5.0 2.8 10500 4.9 40.8 330 10 5 4.0 2.2 | 5.3 41.5 350 6 3 4.0 2.2 10250 5.2 41.4 335 9 5 4.0 2.2 | 5.5 41.9 355 6 3 4.7 2.6 10000 5.5 41.9 340 9 5 6.1 3.4 | 6.0 42.8 005 6 3 9.4 5.2 9750 6.0 42.8 355 9 5 7.6 4.2 | 6.8 44.2 020 6 3 11.3 6.2 9500 6.5 43.7 005 9 5 6.2 3.4 | 7.5 45.5 035 6 3 9.0 5.0 9250 6.9 44.4 015 10 5 4.9 2.7 | 8.1 46.6 035 7 3 6.5 3.6 9000 7.3 45.1 020 10 5 6.2 3.4 | 8.6 47.5 035 7 3 9.5 5.2 8750 7.8 46.0 030 11 6 7.2 3.9 | 9.5 49.1 040 7 3 11.6 6.4 8500 8.2 46.8 035 12 6 5.7 3.1 | 10.2 50.4 040 7 4 9.3 5.1 8250 8.6 47.5 035 12 6 4.3 2.3 | 10.8 51.4 040 7 4 7.9 4.3 8000 9.0 48.2 035 13 7 6.2 3.4 | 11.5 52.7 045 7 4 9.7 5.3 7750 9.5 49.1 035 13 7 8.4 4.6 | 12.2 54.0 045 7 4 10.9 6.0 7500 10.1 50.2 035 13 7 7.4 4.1 | 13.0 55.4 045 7 4 9.4 5.2 7250 10.6 51.1 030 12 6 5.1 2.8 | 13.6 56.5 045 7 4 7.6 4.2 7000 11.1 52.0 025 11 6 10.0 5.5 | 14.3 57.7 045 7 4 11.8 6.5 6750 12.0 53.6 020 10 5 12.5 6.8 | 15.3 59.5 045 7 4 13.1 7.2 6500 12.8 55.0 020 10 5 9.5 5.2 | 16.1 61.0 045 7 4 10.0 5.5 6250 13.5 56.3 020 10 5 10.8 5.9 | 16.9 62.4 045 7 4 11.0 6.0 6000 14.3 57.7 015 10 5 8.6 4.7 | 17.7 63.9 045 7 4 10.1 5.5 5750 15.0 59.0 015 10 5 13.6 7.4 | 18.6 65.5 045 7 4 18.5 10.1 5500 16.5 61.7 015 9 5 27.3 15.0 | 20.6 69.1 045 7 4 33.9 18.6 07/05/2024 at 1500 MDT | 07/05/2024 at 1800 MDT | CAPE... +134.8 LI... -1.2 | CAPE... +198.4 LI... -2.5 CINH... -43.7 K Index... +15.8 | CINH... -52.8 K Index... +20.5 | 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 -59.6 -75.3 290 37 19 3.2 1.8 | -59.3 -74.7 295 40 20 3.7 2.1 45000 -54.1 -65.4 295 53 27 4.2 2.3 | -53.5 -64.3 295 49 25 3.4 1.8 40000 -47.9 -54.2 295 56 29 2.4 1.3 | -48.6 -55.5 300 51 26 2.0 1.1 38000 -46.5 -51.7 295 52 27 2.5 1.4 | -47.4 -53.3 300 47 24 2.1 1.1 36000 -45.0 -49.0 300 47 24 2.6 1.4 | -46.2 -51.2 305 44 22 2.2 1.2 34000 -41.9 -43.4 305 44 23 6.1 3.4 | -42.9 -45.2 305 43 22 6.8 3.7 32000 -37.8 -36.0 315 42 22 6.1 3.3 | -38.3 -36.9 305 44 23 6.8 3.7 30000 -33.3 -27.9 315 42 22 8.0 4.4 | -33.5 -28.3 310 42 22 8.4 4.6 29000 -30.9 -23.6 315 42 22 8.0 4.4 | -31.0 -23.8 310 41 21 8.4 4.6 28000 -28.5 -19.3 315 42 22 7.5 4.1 | -28.4 -19.1 315 40 20 8.0 4.4 27000 -26.6 -15.9 310 41 21 6.4 3.5 | -26.3 -15.3 315 38 19 7.2 4.0 26000 -24.7 -12.5 310 41 21 6.4 3.5 | -24.1 -11.4 310 36 19 7.2 4.0 25000 -22.7 -8.9 305 40 21 6.4 3.5 | -21.9 -7.4 310 34 18 7.5 4.1 24000 -21.0 -5.8 305 38 20 5.6 3.1 | -20.3 -4.5 310 33 17 4.7 2.6 23000 -19.3 -2.7 305 36 18 5.6 3.1 | -18.9 -2.0 310 31 16 4.7 2.6 22000 -17.7 0.1 310 33 17 5.5 3.0 | -17.5 0.5 305 30 15 4.6 2.5 21000 -15.6 3.9 305 32 17 7.5 4.1 | -15.6 3.9 300 29 15 6.9 3.8 20000 -13.4 7.9 305 32 16 7.4 4.1 | -13.6 7.5 300 29 15 6.9 3.8 19500 -12.2 10.0 305 32 16 7.4 4.1 | -12.5 9.5 295 29 15 6.9 3.8 19000 -11.1 12.0 300 32 16 7.7 4.2 | -11.5 11.3 295 29 15 8.1 4.4 18500 -10.0 14.0 300 32 17 7.7 4.2 | -10.3 13.5 290 29 15 8.3 4.6 18000 -8.8 16.2 295 33 17 7.7 4.2 | -9.0 15.8 290 28 15 8.4 4.6 17500 -7.7 18.1 295 33 17 7.7 4.2 | -7.8 18.0 290 28 15 8.7 4.8 17000 -6.6 20.1 295 33 17 7.7 4.2 | -5.8 21.6 290 29 15 8.7 4.8 16500 -4.8 23.4 290 32 17 8.1 4.5 | -4.6 23.7 285 28 15 8.7 4.7 16000 -3.7 25.3 285 32 16 8.2 4.5 | -3.3 26.1 285 28 15 8.7 4.8 15500 -2.5 27.5 285 31 16 7.5 4.1 | -2.1 28.2 285 27 14 8.9 4.9 15000 -1.4 29.5 280 29 15 7.7 4.2 | -0.8 30.6 285 26 13 8.9 4.9 14500 -0.4 31.3 280 28 14 7.8 4.3 | 0.5 32.9 290 24 13 8.7 4.8 14000 0.7 33.3 280 24 13 7.8 4.3 | 1.7 35.1 290 22 11 8.6 4.7 13500 1.8 35.2 285 21 11 6.9 3.8 | 2.9 37.2 290 19 10 6.6 3.6 13000 2.7 36.9 285 17 9 6.1 3.4 | 3.6 38.5 290 14 7 5.2 2.8 12500 3.6 38.5 295 14 7 4.8 2.6 | 4.3 39.7 290 10 5 4.4 2.4 12000 3.9 39.0 300 8 4 3.3 1.8 | 4.7 40.5 290 4 2 3.5 1.9 11500 4.3 39.7 350 3 1 4.7 2.6 | 5.1 41.2 130 1 1 5.2 2.9 11000 5.2 41.4 040 3 1 6.8 3.8 | 6.2 43.2 120 2 1 8.5 4.6 10500 6.1 43.0 065 4 2 4.3 2.3 | 7.5 45.5 120 3 2 5.7 3.1 10250 6.4 43.5 070 4 2 5.3 2.9 | 7.8 46.0 120 3 2 6.5 3.5 10000 7.1 44.8 070 4 2 12.2 6.7 | 8.5 47.3 115 3 2 12.0 6.6 9750 8.0 46.4 070 4 2 14.0 7.7 | 9.4 48.9 115 3 2 12.6 6.9 9500 9.0 48.2 070 4 2 10.6 5.8 | 10.3 50.5 115 3 2 10.4 5.7 9250 9.6 49.3 070 4 2 7.0 3.9 | 11.0 51.8 115 3 2 7.8 4.3 9000 10.2 50.4 070 5 2 10.0 5.5 | 11.6 52.9 110 3 2 9.8 5.4 8750 11.1 52.0 070 5 2 11.6 6.4 | 12.4 54.3 110 3 2 11.1 6.1 8500 11.9 53.4 070 5 2 10.1 5.5 | 13.2 55.8 110 3 2 10.4 5.7 8250 12.6 54.7 070 5 2 9.3 5.1 | 14.0 57.2 110 3 2 10.2 5.6 8000 13.3 55.9 070 5 2 10.0 5.5 | 14.7 58.5 110 3 2 10.1 5.6 7750 14.1 57.4 070 5 2 10.6 5.8 | 15.5 59.9 105 3 2 9.9 5.5 7500 14.9 58.8 070 5 2 10.4 5.7 | 16.2 61.2 105 3 2 10.0 5.5 7250 15.6 60.1 070 5 2 10.1 5.6 | 17.0 62.6 105 3 2 10.3 5.6 7000 16.4 61.5 070 5 2 10.5 5.7 | 17.7 63.9 105 3 2 9.5 5.2 6750 17.2 63.0 070 5 2 10.5 5.8 | 18.4 65.1 105 3 2 9.2 5.1 6500 18.0 64.4 070 5 2 10.4 5.7 | 19.1 66.4 105 3 1 10.5 5.7 6250 18.7 65.7 070 5 2 10.1 5.5 | 19.9 67.8 100 3 1 10.6 5.8 6000 19.5 67.1 070 5 2 11.2 6.2 | 20.7 69.3 100 3 1 11.1 6.1 5750 20.6 69.1 070 5 2 19.7 10.8 | 21.7 71.1 100 3 1 15.9 8.7 5500 22.5 72.5 070 5 2 30.1 16.5 | 23.1 73.6 100 3 1 22.0 12.1 ________________________________________________________________________________ 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