Soaring Guidance
Issued by NWS Grand Junction, CO
Issued by NWS Grand Junction, CO
347 UXUS97 KGJT 201307 SRGGJT Soaring Forecast National Weather Service Grand Junction, Colorado 707 AM MDT Saturday, July 20, 2024 This forecast is for Saturday, July 20, 2024: If the trigger temperature of 85.3 F/29.6 C is reached...then Thermal Soaring Index....................... Excellent Maximum rate of lift........................ 1371 ft/min (7.0 m/s) Maximum height of thermals.................. 19759 ft MSL (14920 ft AGL) Forecast maximum temperature................... 98.0 F/37.1 C Time of trigger temperature.................... 1030 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................. 15670 ft MSL (10830 ft AGL) Thermal soaring outlook for Sunday 07/21....... Excellent Wave Soaring Index............................. Not available Remarks... Sunrise/Sunset.................... 06:05:08 / 20:36:01 MDT Total possible sunshine........... 14 hr 30 min 53 sec (870 min 53 sec) Altitude of sun at 13:20:34 MDT... 70.82 degrees Upper air data from rawinsonde observation taken on 07/20/2024 at 0600 MDT Freezing level.................. 16043 ft MSL (11204 ft AGL) Convective condensation level... 15769 ft MSL (10930 ft AGL) Lifted condensation level....... 17150 ft MSL (12311 ft AGL) Lifted index.................... -3.4 K index......................... +23.5 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 -66.8 -88.2 325 37 19 7.3 4.0 80.4 176.8 25.6 M M 45000 -57.6 -71.7 315 40 21 5.7 3.1 71.4 160.5 21.7 M M 40000 -47.3 -53.1 300 34 18 7.8 4.3 64.7 148.5 18.8 M M 38000 -42.8 -45.0 305 34 17 7.6 4.1 62.6 144.7 17.8 M M 36000 -38.3 -36.9 300 35 18 3.2 1.8 60.7 141.3 16.9 M M 34000 -35.1 -31.2 300 34 17 5.1 2.8 56.1 132.9 14.0 M M 32000 -33.0 -27.4 305 36 19 6.7 3.7 51.0 123.7 10.6 M M 30000 -29.0 -20.2 315 33 17 7.9 4.3 48.5 119.4 8.9 M M 29000 -26.6 -15.9 315 31 16 7.8 4.3 47.8 118.0 8.4 M M 28000 -24.3 -11.7 325 26 13 7.5 4.1 47.0 116.6 8.0 M M 27000 -22.0 -7.6 320 27 14 7.4 4.1 46.1 115.1 7.4 M M 26000 -20.4 -4.7 300 24 12 3.7 2.0 44.6 112.3 6.2 M M 25000 -18.2 -0.8 310 20 10 7.2 4.0 43.6 110.6 5.5 M M 24000 -16.3 2.7 325 17 9 6.5 3.6 42.4 108.3 4.5 M M 23000 -14.0 6.8 325 19 10 7.5 4.1 41.6 107.0 4.0 M M 22000 -12.4 9.7 325 18 9 5.1 2.8 40.1 104.1 2.6 M M 21000 -11.0 12.2 320 15 8 5.3 2.9 38.4 101.1 1.2 M M 20000 -8.8 16.2 345 10 5 6.1 3.3 37.6 99.6 0.4 M M 19500 -7.9 17.8 360 10 5 6.4 3.5 37.0 98.5 -0.2 1358 6.9 19000 -7.0 19.4 355 9 5 6.2 3.4 36.4 97.5 -0.7 1316 6.7 18500 -5.4 22.3 330 7 4 8.9 4.9 35.8 96.4 -1.3 1245 6.3 18000 -4.4 24.1 325 8 4 5.9 3.2 35.3 95.5 -1.8 1201 6.1 17500 -3.6 25.5 325 9 5 7.2 3.9 34.7 94.4 -2.4 1161 5.9 17000 -2.3 27.9 330 9 5 8.7 4.8 34.5 94.1 -2.6 1108 5.6 16500 -1.0 30.2 355 8 4 8.8 4.8 34.3 93.8 -2.7 1054 5.4 16000 0.3 32.5 025 8 4 8.8 4.8 34.2 93.5 -2.9 1000 5.1 15500 1.6 34.9 035 9 5 8.7 4.8 34.0 93.2 -3.1 946 4.8 15000 3.0 37.4 035 9 5 8.6 4.7 33.8 92.9 -3.3 892 4.5 14500 4.3 39.7 015 5 3 10.2 5.6 33.8 92.8 -3.4 836 4.2 14000 5.8 42.4 045 6 3 9.0 4.9 33.8 92.9 -3.4 777 3.9 13500 6.9 44.4 030 5 3 7.8 4.3 33.5 92.3 -3.7 728 3.7 13000 8.0 46.4 035 9 5 7.7 4.2 33.2 91.8 -4.1 680 3.5 12500 9.2 48.6 030 8 4 7.6 4.1 32.9 91.2 -4.4 631 3.2 12000 10.4 50.7 055 4 2 9.0 4.9 32.6 90.7 -4.7 580 2.9 11500 11.7 53.1 065 5 3 8.9 4.9 32.5 90.5 -4.9 526 2.7 11000 13.0 55.4 030 5 3 8.9 4.9 32.4 90.3 -5.0 472 2.4 10500 14.3 57.7 030 7 4 7.9 4.4 32.2 90.0 -5.2 419 2.1 10250 14.8 58.6 025 8 4 7.8 4.3 32.0 89.7 -5.4 395 2.0 10000 15.5 59.9 025 9 5 8.5 4.6 31.9 89.5 -5.5 369 1.9 9750 16.1 61.0 025 9 4 8.7 4.8 31.8 89.3 -5.7 343 1.7 9500 16.7 62.1 030 7 4 7.1 3.9 31.7 89.1 -5.8 316 1.6 9250 17.1 62.8 035 6 3 5.1 2.8 31.4 88.5 -6.1 297 1.5 9000 17.5 63.5 020 8 4 5.3 2.9 31.1 87.9 -6.5 279 1.4 8750 17.8 64.0 015 8 4 5.5 3.0 30.7 87.3 -6.9 261 1.3 8500 18.2 64.8 025 7 4 4.8 2.6 30.4 86.7 -7.3 242 1.2 8250 18.5 65.3 040 6 3 4.6 2.5 30.0 85.9 -7.7 226 1.1 8000 18.9 66.0 050 4 2 7.1 3.9 29.6 85.4 -8.0 206 1.0 7750 19.5 67.1 065 5 3 8.4 4.6 29.5 85.1 -8.2 181 0.9 7500 20.1 68.2 075 8 4 8.1 4.4 29.4 84.9 -8.4 156 0.8 7250 20.7 69.3 070 7 3 8.1 4.5 29.3 84.7 -8.5 131 0.7 7000 21.3 70.3 060 5 3 8.1 4.5 29.2 84.5 -8.7 106 0.5 6750 21.8 71.2 050 5 2 8.1 4.5 29.0 84.3 -8.8 81 0.4 6500 22.4 72.3 035 4 2 8.2 4.5 28.9 84.0 -9.0 56 0.3 6250 23.0 73.4 030 4 2 8.0 4.4 28.8 83.8 -9.2 31 0.2 6000 23.6 74.5 050 5 3 6.7 3.7 28.6 83.5 -9.4 8 0.0 5750 24.0 75.2 055 6 3 6.4 3.5 28.3 83.0 -9.7 M M 5500 24.5 76.1 045 5 3 5.5 3.0 28.1 82.6 -9.9 M M 5250 24.8 76.6 060 5 2 4.7 2.6 27.7 81.9 -10.4 M M 5000 25.2 77.4 080 5 3 3.2 1.8 27.3 81.2 -10.8 M M * * * * * * Numerical weather prediction model forecast data valid * * * * * * 07/20/2024 at 0900 MDT | 07/20/2024 at 1200 MDT | CAPE... +52.4 LI... -1.4 | CAPE... +216.6 LI... -2.0 CINH... -140.8 K Index... +25.5 | CINH... -21.6 K Index... +23.2 | 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 -63.3 -81.9 325 28 14 2.3 1.3 | -63.2 -81.8 315 24 13 2.2 1.2 45000 -57.1 -70.8 315 37 19 6.9 3.8 | -57.3 -71.1 310 35 18 6.6 3.6 40000 -46.7 -52.1 305 36 19 6.9 3.8 | -47.3 -53.1 305 38 19 7.2 3.9 38000 -42.5 -44.5 300 37 19 6.9 3.8 | -43.0 -45.4 300 38 20 7.2 3.9 36000 -38.0 -36.4 300 37 19 4.9 2.7 | -38.3 -36.9 300 38 20 4.8 2.6 34000 -35.2 -31.4 300 35 18 4.6 2.5 | -35.7 -32.3 300 36 18 4.3 2.4 32000 -32.5 -26.5 305 34 17 5.2 2.9 | -33.2 -27.8 300 33 17 5.1 2.8 30000 -28.8 -19.8 310 31 16 6.3 3.5 | -29.3 -20.7 310 30 15 6.6 3.6 29000 -26.9 -16.4 315 29 15 6.3 3.5 | -27.4 -17.3 310 29 15 6.7 3.7 28000 -25.0 -13.0 320 28 14 7.2 3.9 | -25.3 -13.5 315 27 14 7.4 4.1 27000 -22.9 -9.2 315 25 13 7.1 3.9 | -23.1 -9.6 315 25 13 7.3 4.0 26000 -20.8 -5.4 315 23 12 7.1 3.9 | -21.0 -5.8 315 23 12 7.3 4.0 25000 -18.7 -1.7 315 20 10 6.6 3.6 | -18.8 -1.8 315 21 11 6.9 3.8 24000 -16.9 1.6 320 18 9 5.9 3.2 | -16.9 1.6 315 19 10 6.2 3.4 23000 -14.7 5.5 320 15 8 5.9 3.2 | -15.1 4.8 310 17 9 6.3 3.4 22000 -13.0 8.6 325 13 7 6.6 3.6 | -12.8 9.0 310 15 8 6.1 3.4 21000 -11.1 12.0 330 11 6 6.6 3.6 | -11.0 12.2 315 14 7 6.2 3.4 20000 -9.2 15.4 335 9 5 6.6 3.6 | -9.2 15.4 315 12 6 6.3 3.4 19500 -8.3 17.1 335 8 4 7.4 4.1 | -8.3 17.1 320 11 6 7.2 3.9 19000 -7.1 19.2 345 8 4 7.8 4.3 | -7.2 19.0 325 10 5 7.6 4.2 18500 -6.0 21.2 355 8 4 7.9 4.3 | -6.1 21.0 325 9 5 7.7 4.2 18000 -4.8 23.4 005 8 4 7.8 4.3 | -4.9 23.2 330 8 4 8.3 4.5 17500 -3.7 25.3 010 8 4 7.8 4.3 | -3.7 25.3 335 8 4 8.2 4.5 17000 -2.5 27.5 015 8 4 8.2 4.5 | -2.5 27.5 345 7 4 8.5 4.7 16500 -1.2 29.8 020 9 5 8.5 4.6 | -1.2 29.8 350 7 3 8.6 4.7 16000 0.0 32.0 020 9 5 8.5 4.7 | 0.1 32.2 360 7 3 8.7 4.7 15500 1.3 34.3 020 9 5 8.7 4.8 | 1.4 34.5 005 7 4 8.6 4.7 15000 2.5 36.5 020 10 5 8.7 4.8 | 2.6 36.7 010 7 4 8.6 4.7 14500 3.8 38.8 015 10 5 8.7 4.8 | 3.9 39.0 015 8 4 9.0 5.0 14000 5.1 41.2 015 10 5 8.7 4.8 | 5.2 41.4 015 8 4 9.0 4.9 13500 6.4 43.5 015 10 5 8.9 4.9 | 6.6 43.9 020 9 5 9.1 5.0 13000 7.7 45.9 015 10 5 9.0 4.9 | 7.9 46.2 020 10 5 9.1 5.0 12500 9.0 48.2 010 10 5 9.0 4.9 | 9.2 48.6 020 10 5 9.1 5.0 12000 10.3 50.5 015 10 5 9.0 4.9 | 10.6 51.1 025 10 5 9.0 5.0 11500 11.7 53.1 015 10 5 8.7 4.7 | 11.9 53.4 025 11 6 9.0 4.9 11000 12.9 55.2 015 9 5 8.2 4.5 | 13.2 55.8 025 11 5 8.8 4.9 10500 14.1 57.4 020 8 4 7.3 4.0 | 14.5 58.1 030 10 5 7.5 4.1 10250 14.6 58.3 020 8 4 7.0 3.9 | 15.0 59.0 030 10 5 7.9 4.4 10000 15.2 59.4 020 8 4 8.0 4.4 | 15.8 60.4 030 10 5 10.1 5.6 9750 15.8 60.4 025 7 4 7.7 4.2 | 16.5 61.7 030 10 5 9.6 5.2 9500 16.3 61.3 025 7 3 8.0 4.4 | 17.2 63.0 030 9 5 9.6 5.3 9250 16.9 62.4 030 6 3 7.8 4.3 | 17.9 64.2 030 9 5 9.2 5.1 9000 17.4 63.3 030 6 3 6.7 3.7 | 18.5 65.3 030 8 4 8.8 4.8 8750 17.9 64.2 035 5 3 6.2 3.4 | 19.1 66.4 030 8 4 8.7 4.8 8500 18.3 64.9 040 5 3 5.8 3.2 | 19.8 67.6 025 8 4 8.4 4.6 8250 18.7 65.7 045 5 2 5.4 3.0 | 20.9 69.6 025 7 3 9.7 5.3 8000 19.4 66.9 055 4 2 4.4 2.4 | 21.7 71.1 025 7 3 11.9 6.5 7750 19.7 67.5 060 4 2 4.6 2.5 | 22.5 72.5 025 6 3 9.4 5.2 7500 20.0 68.0 065 4 2 4.5 2.5 | 23.1 73.6 025 6 3 7.6 4.2 7250 20.4 68.7 070 4 2 5.1 2.8 | 23.7 74.7 025 6 3 9.6 5.3 7000 20.8 69.4 075 4 2 6.9 3.8 | 24.6 76.3 025 5 3 12.4 6.8 6750 21.3 70.3 075 4 2 7.2 3.9 | 25.5 77.9 025 5 3 11.2 6.1 6500 21.8 71.2 080 4 2 6.7 3.7 | 26.2 79.2 025 5 2 10.5 5.8 6250 22.3 72.1 080 4 2 6.8 3.7 | 27.0 80.6 025 4 2 8.8 4.8 6000 22.9 73.2 080 3 2 11.6 6.3 | 27.8 82.0 025 4 2 15.5 8.5 5750 24.0 75.2 080 3 2 19.5 10.7 | 29.5 85.1 020 4 2 32.9 18.0 5500 25.2 77.4 085 3 2 5.3 2.9 | 31.4 88.5 020 3 2 3.6 2.0 5250 M M M M M M M | M M M M M M M 5000 M M M M M M M | M M M M M M M 07/20/2024 at 1500 MDT | 07/20/2024 at 1800 MDT | CAPE... +152.0 LI... -1.4 | CAPE... +67.0 LI... -0.7 CINH... -8.7 K Index... +24.4 | CINH... -12.3 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 -63.0 -81.4 310 24 12 2.3 1.3 | -62.9 -81.2 310 26 13 2.1 1.2 45000 -57.1 -70.8 305 35 18 6.4 3.5 | -57.0 -70.6 305 38 19 6.6 3.6 40000 -47.4 -53.3 305 39 20 7.0 3.8 | -47.2 -53.0 310 41 21 6.7 3.7 38000 -42.7 -44.9 305 40 21 7.0 3.8 | -42.7 -44.9 305 42 22 6.7 3.7 36000 -38.6 -37.5 305 41 21 5.1 2.8 | -38.8 -37.8 305 43 22 4.9 2.7 34000 -35.7 -32.3 300 37 19 4.7 2.6 | -36.1 -33.0 305 38 19 4.5 2.5 32000 -32.9 -27.2 300 33 17 5.2 2.9 | -33.4 -28.1 300 32 17 5.3 2.9 30000 -29.2 -20.6 300 29 15 6.4 3.5 | -29.5 -21.1 300 29 15 6.7 3.7 29000 -27.3 -17.1 300 27 14 6.4 3.5 | -27.5 -17.5 295 28 15 6.7 3.7 28000 -25.3 -13.5 300 26 13 7.5 4.1 | -25.4 -13.7 295 27 14 7.9 4.3 27000 -23.1 -9.6 300 24 12 7.4 4.1 | -23.1 -9.6 295 24 13 7.8 4.3 26000 -20.9 -5.6 305 23 12 7.4 4.1 | -20.7 -5.3 300 22 11 7.8 4.3 25000 -18.7 -1.7 305 21 11 7.1 3.9 | -18.4 -1.1 300 20 10 7.3 4.0 24000 -16.7 1.9 310 20 10 6.6 3.6 | -16.4 2.5 305 18 9 6.6 3.6 23000 -14.3 6.3 310 18 9 6.7 3.7 | -14.0 6.8 315 15 8 6.7 3.7 22000 -12.4 9.7 315 16 8 6.0 3.3 | -12.0 10.4 320 13 7 6.2 3.4 21000 -10.6 12.9 320 14 7 6.1 3.4 | -10.2 13.6 325 12 6 6.4 3.5 20000 -8.8 16.2 330 12 6 6.2 3.4 | -8.4 16.9 335 10 5 6.6 3.6 19500 -7.9 17.8 335 11 6 7.6 4.2 | -7.5 18.5 340 10 5 7.8 4.3 19000 -6.7 19.9 335 11 6 8.3 4.6 | -6.3 20.7 345 9 5 8.5 4.7 18500 -5.5 22.1 340 10 5 8.4 4.6 | -5.0 23.0 350 9 5 8.5 4.7 18000 -4.2 24.4 345 10 5 8.7 4.8 | -3.8 25.2 355 9 5 9.2 5.0 17500 -3.0 26.6 345 10 5 8.7 4.8 | -2.4 27.7 355 9 5 9.1 5.0 17000 -1.7 28.9 350 9 5 9.0 4.9 | -1.1 30.0 360 9 5 9.0 4.9 16500 -0.3 31.5 355 9 5 9.1 5.0 | 0.2 32.4 005 9 5 8.9 4.9 16000 1.0 33.8 360 9 5 9.1 5.0 | 1.5 34.7 005 9 5 9.0 4.9 15500 2.3 36.1 360 9 5 9.2 5.0 | 2.9 37.2 005 10 5 9.2 5.1 15000 3.7 38.7 005 9 5 9.1 5.0 | 4.3 39.7 010 10 5 9.2 5.0 14500 5.1 41.2 005 10 5 9.5 5.2 | 5.7 42.3 010 10 5 9.5 5.2 14000 6.5 43.7 005 10 5 9.5 5.2 | 7.1 44.8 010 10 5 9.5 5.2 13500 7.9 46.2 005 10 5 9.5 5.2 | 8.5 47.3 010 11 5 9.6 5.3 13000 9.3 48.7 010 10 5 9.6 5.2 | 9.9 49.8 010 11 6 9.6 5.3 12500 10.7 51.3 010 10 5 9.5 5.2 | 11.4 52.5 010 11 6 9.6 5.3 12000 12.1 53.8 010 10 5 9.5 5.2 | 12.8 55.0 010 11 6 9.5 5.2 11500 13.5 56.3 010 10 5 9.5 5.2 | 14.2 57.6 010 11 6 9.5 5.2 11000 15.0 59.0 010 10 5 9.4 5.2 | 15.6 60.1 010 12 6 9.5 5.2 10500 16.4 61.5 010 10 5 7.2 3.9 | 17.1 62.8 010 12 6 7.9 4.3 10250 16.8 62.2 010 9 5 8.1 4.4 | 17.6 63.7 015 12 6 8.5 4.7 10000 17.6 63.7 010 9 5 11.7 6.4 | 18.4 65.1 015 12 6 11.1 6.1 9750 18.4 65.1 010 10 5 11.0 6.0 | 19.2 66.6 015 12 6 10.5 5.7 9500 19.3 66.7 010 10 5 10.2 5.6 | 20.0 68.0 015 12 6 10.4 5.7 9250 20.0 68.0 010 9 5 9.3 5.1 | 20.7 69.3 015 12 6 9.9 5.4 9000 20.7 69.3 010 9 5 10.0 5.5 | 21.4 70.5 015 12 6 9.7 5.3 8750 21.4 70.5 010 9 5 10.4 5.7 | 22.2 72.0 015 12 6 9.8 5.4 8500 22.8 73.0 010 9 5 7.9 4.3 | 22.9 73.2 015 12 6 9.4 5.1 8250 23.5 74.3 015 9 5 10.0 5.5 | 24.2 75.6 015 12 6 9.6 5.3 8000 24.3 75.7 010 9 4 12.3 6.8 | 25.0 77.0 015 12 6 10.9 6.0 7750 25.2 77.4 010 9 4 9.8 5.4 | 25.8 78.4 015 11 6 9.7 5.3 7500 25.8 78.4 010 9 4 7.6 4.2 | 26.4 79.5 015 12 6 8.4 4.6 7250 26.4 79.5 015 8 4 9.5 5.2 | 27.1 80.8 015 12 6 9.4 5.2 7000 27.2 81.0 010 8 4 12.3 6.7 | 27.9 82.2 015 12 6 11.5 6.3 6750 28.2 82.8 010 8 4 11.5 6.3 | 28.7 83.7 015 11 6 10.9 6.0 6500 29.0 84.2 010 8 4 10.8 5.9 | 29.5 85.1 015 11 6 10.2 5.6 6250 29.8 85.6 015 8 4 9.3 5.1 | 30.3 86.5 015 11 6 9.5 5.2 6000 30.5 86.9 010 7 4 13.9 7.6 | 31.0 87.8 015 11 6 11.3 6.2 5750 32.1 89.8 010 7 4 30.1 16.5 | 32.1 89.8 015 10 5 19.9 10.9 5500 34.3 93.7 010 7 4 19.2 10.5 | 33.8 92.8 015 10 5 23.4 12.8 5250 M M M M M M M | M M M M M M M 5000 M M M M M M M | M M M M M M M ________________________________________________________________________________ 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 at Walker Field in Grand Junction, Colorado at North Latitude: 39 deg 07 min 00.001 sec West Longitude: 108 deg 31 min 59.998 sec Elevation: 4839 feet (1475 meters) and may not be representative of other areas along the Western Slope of Colorado. 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