Soaring Guidance
Issued by NWS Grand Junction, CO
Issued by NWS Grand Junction, CO
755 UXUS97 KGJT 121307 SRGGJT Soaring Forecast National Weather Service Grand Junction, Colorado 707 AM MDT Friday, July 12, 2024 This forecast is for Friday, July 12, 2024: If the trigger temperature of 93.5 F/34.1 C is reached...then Thermal Soaring Index....................... Excellent Maximum rate of lift........................ 1852 ft/min (9.4 m/s) Maximum height of thermals.................. 23466 ft MSL (18627 ft AGL) Forecast maximum temperature................... 104.0 F/40.5 C Time of trigger temperature.................... 1100 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................. 18761 ft MSL (13922 ft AGL) Thermal soaring outlook for Saturday 07/13..... Excellent Wave Soaring Index............................. Not available Remarks... Sunrise/Sunset.................... 05:59:01 / 20:40:47 MDT Total possible sunshine........... 14 hr 41 min 46 sec (881 min 46 sec) Altitude of sun at 13:19:54 MDT... 72.18 degrees Upper air data from rawinsonde observation taken on 07/12/2024 at 0600 MDT Freezing level.................. 16968 ft MSL (12129 ft AGL) Convective condensation level... 19769 ft MSL (14930 ft AGL) Lifted condensation level....... 21149 ft MSL (16310 ft AGL) Lifted index.................... -2.9 K index......................... +14.2 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 -60.5 -76.9 295 14 7 3.6 2.0 92.7 198.8 30.6 M M 45000 -58.2 -72.8 330 22 11 3.2 1.8 70.9 159.6 19.3 M M 40000 -53.3 -63.9 320 11 6 7.5 4.1 55.8 132.5 10.6 M M 38000 -48.8 -55.8 355 10 5 7.5 4.1 54.0 129.1 9.6 M M 36000 -45.2 -49.4 325 14 7 6.3 3.5 50.8 123.4 7.6 M M 34000 -40.7 -41.3 320 14 7 8.5 4.6 48.9 120.1 6.4 M M 32000 -35.6 -32.1 335 13 7 8.5 4.7 47.8 118.1 5.8 M M 30000 -29.6 -21.3 340 12 6 8.9 4.9 47.1 116.8 5.4 M M 29000 -27.1 -16.8 335 12 6 7.8 4.3 46.6 115.8 5.1 M M 28000 -24.7 -12.5 325 13 6 7.8 4.3 45.8 114.5 4.5 M M 27000 -22.6 -8.7 295 6 3 6.5 3.6 44.8 112.7 3.8 M M 26000 -21.3 -6.3 315 8 4 5.6 3.1 42.8 109.1 2.2 M M 25000 -19.2 -2.6 335 17 9 8.1 4.4 41.8 107.3 1.4 M M 24000 -17.1 1.2 345 19 10 7.2 3.9 40.8 105.5 0.6 M M 23000 -15.4 4.3 330 21 11 5.2 2.9 39.3 102.8 -0.7 1819 9.2 22000 -14.0 6.8 315 19 10 5.2 2.9 37.7 99.9 -2.2 1746 8.9 21000 -11.5 11.3 315 17 9 10.1 5.6 37.3 99.2 -2.6 1641 8.3 20000 -8.7 16.3 305 12 6 8.8 4.8 37.3 99.1 -2.8 1527 7.8 19500 -7.4 18.7 305 12 6 9.0 4.9 37.1 98.7 -2.9 1473 7.5 19000 -6.0 21.2 310 11 6 9.3 5.1 37.1 98.7 -3.0 1417 7.2 18500 -4.6 23.7 310 11 5 9.3 5.1 37.0 98.7 -3.0 1361 6.9 18000 -3.2 26.2 305 9 5 9.3 5.1 37.0 98.6 -3.1 1305 6.6 17500 -1.8 28.8 295 8 4 9.3 5.1 37.0 98.6 -3.1 1248 6.3 17000 -0.4 31.3 290 7 4 9.3 5.1 37.0 98.6 -3.1 1192 6.1 16500 1.6 34.9 285 8 4 9.3 5.1 36.9 98.5 -3.2 1107 5.6 16000 3.0 37.4 285 10 5 9.3 5.1 36.9 98.4 -3.3 1051 5.3 15500 4.4 39.9 290 12 6 9.3 5.1 36.8 98.3 -3.4 995 5.1 15000 5.8 42.4 285 13 7 9.3 5.1 36.7 98.1 -3.4 938 4.8 14500 7.2 45.0 275 12 6 9.3 5.1 36.7 98.0 -3.5 882 4.5 14000 8.6 47.5 265 12 6 9.3 5.1 36.6 97.9 -3.6 826 4.2 13500 10.0 50.0 265 12 6 9.3 5.1 36.5 97.7 -3.7 769 3.9 13000 11.4 52.5 260 13 7 9.3 5.1 36.4 97.5 -3.9 713 3.6 12500 12.7 54.9 260 15 7 9.3 5.1 36.3 97.3 -4.0 656 3.3 12000 14.1 57.4 255 16 8 9.3 5.1 36.2 97.1 -4.1 600 3.0 11500 15.5 59.9 255 16 8 9.3 5.1 36.1 96.9 -4.3 544 2.8 11000 16.9 62.4 255 14 7 9.3 5.1 35.9 96.7 -4.4 487 2.5 10500 18.3 64.9 260 12 6 8.5 4.6 35.8 96.4 -4.6 431 2.2 10250 18.9 66.0 270 11 6 7.7 4.2 35.6 96.2 -4.7 407 2.1 10000 19.4 66.9 280 10 5 7.9 4.3 35.5 95.9 -4.9 382 1.9 9750 20.0 68.0 280 10 5 7.9 4.3 35.4 95.7 -5.0 357 1.8 9500 20.6 69.1 280 10 5 7.9 4.3 35.2 95.4 -5.2 332 1.7 9250 21.2 70.2 275 8 4 7.9 4.3 35.1 95.1 -5.3 308 1.6 9000 21.8 71.2 270 5 3 7.9 4.3 34.9 94.9 -5.5 283 1.4 8750 22.3 72.1 260 3 2 7.9 4.3 34.8 94.6 -5.7 258 1.3 8500 22.9 73.2 225 2 1 7.9 4.3 34.6 94.3 -5.8 233 1.2 8250 23.5 74.3 165 2 1 8.0 4.4 34.5 94.1 -6.0 209 1.1 8000 24.1 75.4 140 3 2 7.5 4.1 34.3 93.8 -6.2 184 0.9 7750 24.6 76.3 130 6 3 5.7 3.1 34.1 93.4 -6.4 162 0.8 7500 24.9 76.8 125 9 5 5.5 3.0 33.8 92.8 -6.8 144 0.7 7250 25.1 77.2 125 13 7 -1.4 -0.8 33.3 91.9 -7.3 130 0.7 7000 24.9 76.8 135 16 8 1.1 0.6 32.3 90.1 -8.4 131 0.7 6750 25.4 77.7 135 16 8 8.2 4.5 32.1 89.7 -8.6 108 0.6 6500 25.9 78.6 130 15 8 8.0 4.4 31.9 89.3 -8.9 86 0.4 6250 26.4 79.5 135 16 8 1.8 1.0 31.7 89.0 -9.1 64 0.3 6000 26.0 78.8 145 18 9 -6.0 -3.3 30.6 87.1 -10.2 66 0.3 5750 25.6 78.1 140 18 9 -4.6 -2.5 29.5 85.1 -11.4 71 0.4 5500 25.2 77.4 145 19 10 -5.4 -2.9 28.4 83.1 -12.5 76 0.4 5250 24.8 76.6 145 20 10 -3.6 -2.0 27.3 81.1 -13.7 81 0.4 5000 24.4 75.9 140 19 10 -9.7 -5.3 26.2 79.1 -14.9 86 0.4 * * * * * * Numerical weather prediction model forecast data valid * * * * * * 07/12/2024 at 0900 MDT | 07/12/2024 at 1200 MDT | CAPE... +9.5 LI... +0.8 | CAPE... +123.6 LI... +0.2 CINH... -117.0 K Index... +15.5 | CINH... -43.9 K Index... +14.6 | 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 -61.4 -78.5 340 6 3 2.6 1.4 | -61.2 -78.2 305 3 1 2.0 1.1 45000 -57.5 -71.5 340 13 7 2.5 1.4 | -57.2 -71.0 315 7 4 4.0 2.2 40000 -52.7 -62.9 320 18 9 6.2 3.4 | -50.9 -59.6 320 17 8 4.2 2.3 38000 -49.0 -56.2 320 15 8 6.2 3.4 | -48.4 -55.1 315 14 7 4.2 2.3 36000 -45.3 -49.5 315 12 6 7.2 4.0 | -45.9 -50.6 305 11 6 6.4 3.5 34000 -40.3 -40.5 315 11 6 8.3 4.6 | -40.7 -41.3 300 10 5 8.6 4.7 32000 -35.3 -31.5 310 11 6 8.4 4.6 | -35.5 -31.9 290 9 5 8.6 4.7 30000 -30.4 -22.7 305 9 5 8.2 4.5 | -30.7 -23.3 280 8 4 8.0 4.4 29000 -27.9 -18.2 305 8 4 8.2 4.5 | -28.3 -18.9 270 7 4 8.0 4.4 28000 -25.5 -13.9 305 8 4 6.5 3.6 | -26.0 -14.8 270 7 4 6.5 3.6 27000 -23.6 -10.5 310 9 5 6.6 3.6 | -24.0 -11.2 285 7 4 6.7 3.7 26000 -21.1 -6.0 310 11 5 6.6 3.6 | -21.5 -6.7 300 7 4 6.7 3.7 25000 -19.2 -2.6 315 12 6 5.7 3.1 | -19.6 -3.3 315 8 4 6.4 3.5 24000 -17.5 0.5 320 14 7 5.8 3.2 | -17.6 0.3 330 10 5 6.5 3.6 23000 -15.8 3.6 325 15 8 5.9 3.3 | -15.7 3.7 340 11 6 6.6 3.6 22000 -13.9 7.0 325 16 8 9.2 5.0 | -13.6 7.5 340 13 7 9.2 5.0 21000 -11.3 11.7 325 14 7 8.9 4.9 | -11.0 12.2 330 12 6 9.0 4.9 20000 -8.7 16.3 320 13 6 8.9 4.9 | -8.4 16.9 325 12 6 9.1 5.0 19500 -7.4 18.7 320 12 6 9.5 5.2 | -7.1 19.2 320 12 6 9.4 5.1 19000 -5.9 21.4 315 11 6 9.7 5.3 | -5.7 21.7 315 11 6 9.5 5.2 18500 -4.5 23.9 315 10 5 9.7 5.3 | -4.3 24.3 315 11 5 9.5 5.2 18000 -3.0 26.6 310 9 5 9.5 5.2 | -2.8 27.0 310 10 5 9.5 5.2 17500 -1.6 29.1 310 9 5 9.5 5.2 | -1.4 29.5 310 10 5 9.5 5.2 17000 -0.2 31.6 310 8 4 9.3 5.1 | -0.0 32.0 310 9 5 9.3 5.1 16500 1.2 34.2 310 8 4 9.2 5.1 | 1.4 34.5 310 8 4 9.2 5.1 16000 2.5 36.5 315 7 4 9.2 5.0 | 2.7 36.9 310 8 4 9.2 5.1 15500 3.9 39.0 315 6 3 9.0 4.9 | 4.1 39.4 310 7 4 9.2 5.0 15000 5.2 41.4 320 6 3 9.0 4.9 | 5.5 41.9 310 6 3 9.2 5.0 14500 6.6 43.9 325 6 3 8.9 4.9 | 6.8 44.2 310 5 3 8.8 4.8 14000 7.9 46.2 335 6 3 8.9 4.9 | 8.2 46.8 315 4 2 8.9 4.9 13500 9.3 48.7 340 5 3 8.8 4.8 | 9.5 49.1 315 3 2 8.9 4.9 13000 10.6 51.1 350 5 3 8.8 4.8 | 10.8 51.4 330 2 1 8.8 4.9 12500 11.9 53.4 355 5 3 8.7 4.7 | 12.2 54.0 350 2 1 8.9 4.9 12000 13.2 55.8 360 5 2 8.5 4.7 | 13.5 56.3 010 2 1 8.9 4.9 11500 14.4 57.9 360 4 2 8.4 4.6 | 14.8 58.6 030 2 1 8.9 4.9 11000 15.7 60.3 360 3 2 8.2 4.5 | 16.2 61.2 035 2 1 8.7 4.8 10500 16.9 62.4 355 3 1 6.8 3.8 | 17.5 63.5 045 3 1 6.3 3.5 10250 17.3 63.1 345 2 1 6.9 3.8 | 17.9 64.2 050 2 1 7.2 3.9 10000 18.0 64.4 335 2 1 8.7 4.8 | 18.6 65.5 050 2 1 10.9 6.0 9750 18.6 65.5 310 1 1 8.4 4.6 | 19.4 66.9 050 2 1 10.4 5.7 9500 19.2 66.6 265 1 0 7.7 4.2 | 20.1 68.2 045 2 1 8.7 4.8 9250 19.7 67.5 235 1 1 6.4 3.5 | 20.7 69.3 050 2 1 7.5 4.1 9000 20.6 69.1 190 2 1 6.1 3.4 | 22.0 71.6 040 1 1 9.9 5.4 8750 21.0 69.8 185 3 1 5.6 3.1 | 22.7 72.9 035 1 0 8.2 4.5 8500 21.4 70.5 185 3 1 4.8 2.6 | 23.2 73.8 045 1 0 5.8 3.2 8250 21.7 71.1 180 3 2 5.7 3.2 | 23.6 74.5 060 1 0 8.6 4.7 8000 22.2 72.0 180 3 2 6.7 3.7 | 24.4 75.9 000 0 0 10.9 6.0 7750 22.6 72.7 180 4 2 4.6 2.5 | 25.1 77.2 000 0 0 8.9 4.9 7500 22.8 73.0 170 4 2 2.8 1.6 | 25.7 78.3 000 0 0 7.2 4.0 7250 23.1 73.6 165 4 2 4.1 2.2 | 26.2 79.2 000 0 0 9.4 5.2 7000 23.4 74.1 160 5 2 6.2 3.4 | 27.1 80.8 000 0 0 12.8 7.0 6750 23.9 75.0 155 5 3 6.3 3.4 | 28.0 82.4 000 0 0 11.4 6.3 6500 24.3 75.7 145 5 3 5.6 3.1 | 28.8 83.8 000 0 0 10.3 5.6 6250 24.7 76.5 140 6 3 5.5 3.0 | 29.5 85.1 000 0 0 9.1 5.0 6000 25.2 77.4 135 5 3 11.0 6.0 | 30.3 86.5 000 0 0 14.5 8.0 5750 26.4 79.5 135 5 3 20.8 11.4 | 31.9 89.4 000 0 0 29.8 16.4 5500 27.6 81.7 130 5 3 2.6 1.4 | 33.8 92.8 290 1 0 9.6 5.3 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 07/12/2024 at 1500 MDT | 07/12/2024 at 1800 MDT | CAPE... +15.9 LI... -0.1 | CAPE... +13.9 LI... -0.0 CINH... -21.6 K Index... +13.6 | CINH... -19.4 K Index... +13.8 | 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 -61.6 -78.9 225 6 3 0.8 0.5 | -62.0 -79.6 245 8 4 0.7 0.4 45000 -57.7 -71.9 280 8 4 5.3 2.9 | -58.1 -72.6 275 10 5 5.5 3.0 40000 -50.2 -58.4 315 14 7 3.6 2.0 | -50.2 -58.4 295 11 6 4.1 2.2 38000 -48.0 -54.4 295 13 7 3.6 2.0 | -47.7 -53.9 285 14 7 4.1 2.2 36000 -45.8 -50.4 280 13 7 6.0 3.3 | -45.3 -49.5 280 18 9 6.1 3.3 34000 -40.8 -41.4 275 13 7 8.4 4.6 | -40.5 -40.9 275 18 9 8.0 4.4 32000 -35.7 -32.3 270 13 7 8.4 4.6 | -35.7 -32.3 270 17 9 8.1 4.4 30000 -30.9 -23.6 265 13 7 8.1 4.4 | -31.0 -23.8 275 16 8 7.8 4.3 29000 -28.4 -19.1 265 13 7 8.1 4.4 | -28.7 -19.7 280 16 8 7.8 4.3 28000 -26.1 -15.0 265 12 6 7.0 3.9 | -26.4 -15.5 280 15 8 7.3 4.0 27000 -23.4 -10.1 275 10 5 7.1 3.9 | -23.6 -10.5 285 12 6 7.4 4.1 26000 -21.3 -6.3 290 8 4 7.1 3.9 | -21.4 -6.5 295 10 5 7.4 4.1 25000 -19.1 -2.4 305 6 3 7.5 4.1 | -19.2 -2.6 305 8 4 8.2 4.5 24000 -16.9 1.6 330 7 3 7.5 4.1 | -16.8 1.8 320 6 3 8.2 4.5 23000 -14.7 5.5 345 7 4 7.5 4.1 | -14.4 6.1 340 5 3 8.2 4.5 22000 -12.4 9.7 355 8 4 8.4 4.6 | -11.9 10.6 360 5 3 8.6 4.7 21000 -9.9 14.2 355 8 4 8.4 4.6 | -9.4 15.1 015 5 3 8.6 4.7 20000 -7.5 18.5 350 8 4 8.5 4.7 | -6.9 19.6 025 6 3 8.6 4.7 19500 -6.2 20.8 350 8 4 9.1 5.0 | -5.6 21.9 030 6 3 8.9 4.9 19000 -4.9 23.2 345 8 4 9.3 5.1 | -4.2 24.4 025 6 3 9.0 5.0 18500 -3.5 25.7 345 7 4 9.3 5.1 | -2.9 26.8 025 6 3 9.0 5.0 18000 -2.1 28.2 340 7 4 9.4 5.2 | -1.5 29.3 025 6 3 9.2 5.1 17500 -0.7 30.7 340 7 3 9.4 5.2 | -0.2 31.6 025 6 3 9.2 5.1 17000 0.7 33.3 340 6 3 9.4 5.2 | 1.2 34.2 025 6 3 9.4 5.2 16500 2.1 35.8 340 6 3 9.5 5.2 | 2.7 36.9 020 6 3 9.5 5.2 16000 3.5 38.3 340 6 3 9.5 5.2 | 4.1 39.4 020 6 3 9.5 5.2 15500 4.9 40.8 340 5 3 9.5 5.2 | 5.5 41.9 020 6 3 9.6 5.3 15000 6.3 43.3 340 5 3 9.4 5.2 | 6.9 44.4 020 6 3 9.6 5.3 14500 7.8 46.0 340 5 3 9.6 5.3 | 8.4 47.1 015 6 3 9.5 5.2 14000 9.2 48.6 340 5 2 9.6 5.3 | 9.8 49.6 015 6 3 9.5 5.2 13500 10.6 51.1 340 4 2 9.5 5.2 | 11.2 52.2 015 6 3 9.5 5.2 13000 12.0 53.6 340 4 2 9.5 5.2 | 12.7 54.9 010 6 3 9.5 5.2 12500 13.5 56.3 340 4 2 9.5 5.2 | 14.1 57.4 010 6 3 9.6 5.3 12000 14.9 58.8 340 4 2 9.5 5.2 | 15.6 60.1 010 6 3 9.7 5.3 11500 16.3 61.3 340 4 2 9.5 5.2 | 17.0 62.6 005 5 3 9.4 5.2 11000 17.7 63.9 340 3 2 9.3 5.1 | 18.4 65.1 360 5 2 8.9 4.9 10500 19.1 66.4 340 3 2 6.7 3.7 | 19.7 67.5 355 4 2 10.9 6.0 10250 19.5 67.1 340 3 2 7.3 4.0 | 20.6 69.1 355 5 2 11.4 6.3 10000 20.3 68.5 340 3 2 11.3 6.2 | 21.3 70.3 355 5 2 9.0 4.9 9750 21.1 70.0 340 3 2 10.4 5.7 | 22.0 71.6 350 4 2 9.7 5.3 9500 21.9 71.4 340 3 2 9.8 5.4 | 23.4 74.1 335 3 2 9.4 5.1 9250 22.6 72.7 340 3 2 9.1 5.0 | 24.1 75.4 335 3 2 9.5 5.2 9000 23.3 73.9 335 3 2 9.7 5.3 | 24.8 76.6 335 4 2 9.6 5.3 8750 24.7 76.5 335 3 2 9.1 5.0 | 25.5 77.9 335 4 2 9.2 5.0 8500 25.3 77.5 330 3 2 7.7 4.2 | 26.2 79.2 330 4 2 8.3 4.6 8250 26.0 78.8 330 3 2 9.9 5.4 | 26.9 80.4 320 3 2 9.7 5.3 8000 26.8 80.2 330 3 2 12.3 6.7 | 27.7 81.9 325 4 2 11.3 6.2 7750 27.7 81.9 325 3 1 9.8 5.4 | 28.4 83.1 330 4 2 9.8 5.4 7500 28.3 82.9 320 3 2 7.5 4.1 | 29.1 84.4 325 4 2 8.0 4.4 7250 28.9 84.0 320 3 2 9.5 5.2 | 29.7 85.5 315 4 2 9.0 5.0 7000 29.7 85.5 320 3 2 12.4 6.8 | 30.5 86.9 315 4 2 11.4 6.3 6750 30.6 87.1 315 3 1 11.4 6.3 | 31.3 88.3 320 4 2 11.0 6.1 6500 31.4 88.5 315 3 1 10.4 5.7 | 32.1 89.8 315 4 2 10.3 5.7 6250 32.2 90.0 310 3 2 9.3 5.1 | 32.9 91.2 310 4 2 9.9 5.4 6000 33.0 91.4 310 3 1 13.8 7.6 | 33.6 92.5 305 4 2 10.2 5.6 5750 34.5 94.1 310 3 1 28.8 15.8 | 34.6 94.3 315 4 2 16.5 9.1 5500 36.7 98.1 305 3 2 21.7 11.9 | 36.2 97.2 305 4 2 29.7 16.3 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