Soaring Guidance
Issued by NWS Grand Junction, CO
Issued by NWS Grand Junction, CO
075 UXUS97 KGJT 171307 SRGGJT Soaring Forecast National Weather Service Grand Junction, Colorado 707 AM MDT Friday, May 17, 2024 This forecast is for Friday, May 17, 2024: If the trigger temperature of 73.3 F/22.9 C is reached...then Thermal Soaring Index....................... Excellent Maximum rate of lift........................ 1241 ft/min (6.3 m/s) Maximum height of thermals.................. 18621 ft MSL (13782 ft AGL) Forecast maximum temperature................... 86.0 F/30.5 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................. 15706 ft MSL (10867 ft AGL) Thermal soaring outlook for Saturday 05/18..... Excellent Wave Soaring Index............................. Not available Remarks... Sunrise/Sunset.................... 05:58:36 / 20:22:33 MDT Total possible sunshine........... 14 hr 23 min 57 sec (863 min 57 sec) Altitude of sun at 13:10:34 MDT... 70.32 degrees Upper air data from rawinsonde observation taken on 05/17/2024 at 0600 MDT Freezing level.................. 12827 ft MSL (7988 ft AGL) Convective condensation level... 18251 ft MSL (13412 ft AGL) Lifted condensation level....... 18636 ft MSL (13797 ft AGL) Lifted index.................... -0.7 K index......................... +15.3 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 -57.9 -72.2 320 24 12 3.8 2.1 102.1 215.8 41.4 M M 45000 -61.9 -79.4 345 39 20 -5.8 -3.2 70.8 159.5 25.1 M M 40000 -58.6 -73.5 010 36 19 5.7 3.1 52.9 127.2 15.1 M M 38000 -54.9 -66.8 350 42 21 4.1 2.2 48.5 119.4 12.6 M M 36000 -51.7 -61.1 350 38 19 6.4 3.5 44.6 112.3 10.2 M M 34000 -47.6 -53.7 335 33 17 7.4 4.0 42.2 107.9 8.7 M M 32000 -43.0 -45.4 355 21 11 8.2 4.5 40.5 104.9 7.7 M M 30000 -37.7 -35.9 350 21 11 9.5 5.2 39.7 103.5 7.3 M M 29000 -35.0 -31.0 325 20 10 8.1 4.4 39.3 102.8 7.1 M M 28000 -32.6 -26.7 320 21 11 8.6 4.7 38.7 101.6 6.7 M M 27000 -30.0 -22.0 325 26 13 8.8 4.8 38.3 101.0 6.5 M M 26000 -27.3 -17.1 325 24 12 8.4 4.6 37.9 100.2 6.2 M M 25000 -25.0 -13.0 315 29 15 6.7 3.7 37.1 98.7 5.7 M M 24000 -23.0 -9.4 295 23 12 5.3 2.9 35.9 96.7 4.8 M M 23000 -21.8 -7.2 285 23 12 4.1 2.2 33.9 93.0 3.1 M M 22000 -19.8 -3.6 285 23 12 8.2 4.5 32.7 90.9 2.2 M M 21000 -17.6 0.3 285 26 13 7.0 3.8 31.9 89.3 1.5 M M 20000 -14.8 5.4 270 17 9 7.7 4.2 30.9 87.6 0.7 M M 19500 -13.7 7.3 270 17 9 7.8 4.3 30.6 87.0 0.4 M M 19000 -12.5 9.5 275 13 7 8.1 4.4 30.3 86.5 0.2 M M 18500 -11.3 11.7 270 15 8 7.8 4.3 29.9 85.9 -0.1 1219 6.2 18000 -10.1 13.8 275 16 8 8.1 4.4 29.6 85.3 -0.5 1170 5.9 17500 -8.9 16.0 280 20 10 8.2 4.5 29.3 84.8 -0.7 1117 5.7 17000 -7.6 18.3 285 24 12 6.6 3.6 29.1 84.4 -0.8 1064 5.4 16500 -6.9 19.6 285 29 15 4.3 2.3 28.2 82.8 -1.7 1030 5.2 16000 -6.4 20.5 280 20 10 4.3 2.4 27.3 81.1 -2.6 997 5.1 15500 -5.7 21.7 270 19 10 5.0 2.7 26.4 79.5 -3.5 964 4.9 15000 -5.0 23.0 270 20 10 5.3 2.9 25.6 78.1 -4.3 929 4.7 14500 -4.4 24.1 260 21 11 5.7 3.1 24.9 76.8 -5.1 893 4.5 14000 -3.2 26.2 265 19 10 9.7 5.3 24.6 76.3 -5.4 844 4.3 13500 -1.8 28.8 265 18 9 9.4 5.1 24.5 76.2 -5.5 787 4.0 13000 -0.4 31.3 260 16 8 9.4 5.1 24.5 76.1 -5.6 731 3.7 12500 1.0 33.8 260 13 7 9.4 5.1 24.4 75.9 -5.7 674 3.4 12000 2.4 36.3 265 11 6 9.4 5.1 24.3 75.8 -5.8 617 3.1 11500 3.8 38.8 270 10 5 9.4 5.1 24.3 75.7 -5.9 561 2.8 11000 5.2 41.4 265 8 4 9.4 5.1 24.2 75.5 -6.0 504 2.6 10500 6.5 43.7 260 7 4 9.0 5.0 24.1 75.3 -6.1 448 2.3 10250 7.2 45.0 255 6 3 9.0 4.9 24.0 75.2 -6.2 420 2.1 10000 7.9 46.2 255 7 4 8.7 4.8 24.0 75.1 -6.3 393 2.0 9750 8.5 47.3 275 7 3 8.5 4.7 23.9 74.9 -6.4 366 1.9 9500 9.2 48.6 295 7 3 8.6 4.7 23.8 74.8 -6.5 339 1.7 9250 9.8 49.6 300 6 3 8.5 4.7 23.7 74.6 -6.6 312 1.6 9000 10.5 50.9 240 8 4 8.6 4.7 23.6 74.4 -6.7 286 1.5 8750 11.1 52.0 235 9 5 7.6 4.2 23.5 74.2 -6.8 259 1.3 8500 11.6 52.9 240 8 4 6.9 3.8 23.2 73.8 -7.0 236 1.2 8250 12.1 53.8 260 4 2 7.1 3.9 23.0 73.5 -7.3 213 1.1 8000 12.7 54.9 265 5 2 7.0 3.8 22.8 73.1 -7.5 190 1.0 7750 13.2 55.8 270 5 3 7.2 4.0 22.6 72.7 -7.7 167 0.8 7500 13.7 56.7 270 6 3 7.7 4.2 22.4 72.4 -7.9 143 0.7 7250 14.3 57.7 265 4 2 7.8 4.3 22.3 72.1 -8.1 118 0.6 7000 14.9 58.8 225 1 1 7.8 4.3 22.1 71.9 -8.3 93 0.5 6750 15.5 59.9 185 2 1 7.9 4.3 22.0 71.6 -8.4 69 0.3 6500 16.1 61.0 145 6 3 7.5 4.1 21.8 71.3 -8.6 44 0.2 6250 16.5 61.7 140 10 5 2.7 1.5 21.5 70.8 -8.9 24 0.1 6000 16.4 61.5 135 15 8 -6.1 -3.4 20.7 69.2 -9.8 20 0.1 5750 15.8 60.4 140 17 9 -5.8 -3.2 19.3 66.8 -11.2 30 0.2 5500 15.5 59.9 140 18 9 -3.5 -1.9 18.3 65.0 -12.2 31 0.2 5250 14.9 58.8 140 17 9 -12.4 -6.8 17.1 62.7 -13.6 42 0.2 5000 13.5 56.3 135 13 7 -20.6 -11.3 15.0 59.0 -15.7 75 0.4 * * * * * * Numerical weather prediction model forecast data valid * * * * * * 05/17/2024 at 0900 MDT | 05/17/2024 at 1200 MDT | CAPE... 0.0 LI... +3.8 | CAPE... +1.1 LI... +2.2 CINH... -0.0 K Index... +7.7 | CINH... -0.2 K Index... +12.7 | 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 -60.4 -76.7 305 21 11 -0.5 -0.2 | -61.4 -78.5 290 19 10 -0.7 -0.4 45000 -60.7 -77.3 330 29 15 1.8 1.0 | -61.8 -79.2 320 21 11 3.1 1.7 40000 -58.0 -72.4 350 34 17 1.8 1.0 | -56.8 -70.2 335 21 11 3.6 2.0 38000 -54.4 -65.9 350 31 16 6.0 3.3 | -53.4 -64.1 325 22 11 5.8 3.2 36000 -50.8 -59.4 345 28 14 6.0 3.3 | -49.9 -57.8 310 23 12 5.8 3.2 34000 -46.7 -52.1 335 25 13 7.7 4.2 | -45.8 -50.4 305 24 12 7.5 4.1 32000 -42.0 -43.6 325 22 11 7.7 4.2 | -41.3 -42.3 305 23 12 7.5 4.1 30000 -37.4 -35.3 310 21 11 7.9 4.3 | -36.6 -33.9 305 23 12 8.1 4.4 29000 -35.0 -31.0 305 22 11 7.9 4.3 | -34.2 -29.6 300 23 12 8.1 4.4 28000 -32.6 -26.7 300 22 12 7.9 4.3 | -31.8 -25.2 300 23 12 8.0 4.4 27000 -30.3 -22.5 300 23 12 7.7 4.2 | -29.5 -21.1 300 23 12 7.6 4.2 26000 -28.0 -18.4 300 23 12 7.7 4.2 | -27.2 -17.0 300 23 12 7.6 4.2 25000 -25.6 -14.1 295 22 12 7.7 4.2 | -24.9 -12.8 295 24 12 7.6 4.2 24000 -23.4 -10.1 295 22 12 7.1 3.9 | -22.2 -8.0 295 25 13 6.3 3.4 23000 -20.7 -5.3 295 23 12 7.1 3.9 | -20.4 -4.7 290 26 14 6.3 3.4 22000 -18.6 -1.5 295 23 12 7.1 3.9 | -18.5 -1.3 290 28 14 6.3 3.4 21000 -16.5 2.3 295 23 12 6.9 3.8 | -16.6 2.1 285 28 14 6.4 3.5 20000 -14.4 6.1 295 22 11 6.9 3.8 | -14.7 5.5 285 27 14 6.4 3.5 19500 -13.4 7.9 290 22 11 6.9 3.8 | -13.7 7.3 285 26 13 6.4 3.5 19000 -12.4 9.7 290 22 11 6.7 3.7 | -12.8 9.0 285 26 13 6.2 3.4 18500 -11.5 11.3 290 22 11 5.7 3.1 | -11.9 10.6 285 25 13 5.5 3.0 18000 -10.6 12.9 290 22 11 5.7 3.1 | -11.1 12.0 280 24 12 5.5 3.0 17500 -9.7 14.5 290 22 11 6.2 3.4 | -10.3 13.5 280 23 12 6.4 3.5 17000 -8.8 16.2 290 22 11 6.2 3.4 | -9.3 15.3 280 23 12 6.5 3.6 16500 -7.9 17.8 285 22 11 6.3 3.5 | -8.4 16.9 280 23 12 6.6 3.6 16000 -7.0 19.4 285 21 11 6.5 3.5 | -7.4 18.7 280 22 11 6.8 3.7 15500 -6.0 21.2 285 20 10 6.5 3.6 | -6.4 20.5 280 22 11 6.8 3.7 15000 -5.1 22.8 285 19 10 7.0 3.8 | -5.4 22.3 280 21 11 7.5 4.1 14500 -4.1 24.6 280 18 9 6.9 3.8 | -4.3 24.3 280 21 11 7.4 4.0 14000 -3.0 26.6 280 17 9 7.7 4.2 | -3.2 26.2 275 20 10 8.7 4.8 13500 -1.9 28.6 275 16 8 7.7 4.2 | -1.9 28.6 275 19 10 8.8 4.8 13000 -0.7 30.7 275 15 8 8.2 4.5 | -0.6 30.9 275 18 9 9.1 5.0 12500 0.5 32.9 270 15 8 8.4 4.6 | 0.8 33.4 275 17 9 9.1 5.0 12000 1.7 35.1 265 14 7 8.5 4.7 | 2.1 35.8 270 17 9 9.2 5.1 11500 3.0 37.4 265 14 7 8.6 4.7 | 3.5 38.3 270 16 8 9.2 5.1 11000 4.2 39.6 265 14 7 7.6 4.2 | 4.9 40.8 270 15 8 8.4 4.6 10500 5.2 41.4 260 13 7 6.0 3.3 | 6.0 42.8 270 15 8 6.9 3.8 10250 5.7 42.3 260 13 7 10.3 5.6 | 6.6 43.9 270 14 7 11.2 6.1 10000 6.7 44.1 260 12 6 10.8 5.9 | 7.6 45.7 265 14 7 12.1 6.6 9750 7.2 45.0 255 12 6 6.8 3.7 | 8.3 46.9 265 13 7 8.2 4.5 9500 7.8 46.0 255 11 6 8.2 4.5 | 9.0 48.2 265 13 7 9.7 5.3 9250 8.4 47.1 255 11 6 6.8 3.7 | 9.7 49.5 265 13 6 7.7 4.2 9000 8.8 47.8 255 11 6 6.7 3.7 | 10.2 50.4 265 12 6 8.1 4.4 8750 9.4 48.9 250 10 5 7.6 4.2 | 10.9 51.6 265 12 6 9.9 5.5 8500 9.9 49.8 250 9 5 7.7 4.2 | 11.6 52.9 265 11 6 9.7 5.3 8250 10.5 50.9 245 8 4 6.7 3.7 | 12.9 55.2 265 10 5 8.7 4.8 8000 11.4 52.5 245 7 4 6.4 3.5 | 13.6 56.5 265 10 5 10.2 5.6 7750 11.9 53.4 240 6 3 7.5 4.1 | 14.4 57.9 265 9 5 11.0 6.0 7500 12.4 54.3 230 5 3 5.1 2.8 | 15.2 59.4 265 9 5 9.1 5.0 7250 12.7 54.9 225 5 2 2.8 1.5 | 15.8 60.4 270 9 5 7.5 4.1 7000 13.0 55.4 220 4 2 7.6 4.2 | 16.4 61.5 270 9 4 10.7 5.9 6750 13.7 56.7 210 4 2 10.3 5.6 | 17.3 63.1 270 8 4 12.5 6.8 6500 14.4 57.9 200 4 2 8.1 4.5 | 18.2 64.8 265 8 4 10.7 5.9 6250 15.0 59.0 190 3 2 7.5 4.1 | 19.0 66.2 270 8 4 10.5 5.8 6000 15.6 60.1 180 3 2 8.1 4.5 | 19.8 67.6 275 7 4 8.4 4.6 5750 16.3 61.3 185 3 2 13.5 7.4 | 20.4 68.7 270 7 4 14.0 7.7 5500 18.0 64.4 170 3 1 38.0 20.9 | 23.3 73.9 280 6 3 81.9 44.9 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 05/17/2024 at 1500 MDT | 05/17/2024 at 1800 MDT | CAPE... +3.5 LI... +0.9 | CAPE... +11.3 LI... 0.0 CINH... -0.1 K Index... +13.9 | CINH... -15.5 K Index... +16.4 | 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 -61.7 -79.1 280 24 12 -0.9 -0.5 | -61.4 -78.5 275 28 14 -0.1 -0.1 45000 -62.2 -80.0 300 20 10 3.5 1.9 | -61.0 -77.8 280 23 12 2.7 1.5 40000 -56.6 -69.9 295 18 9 4.1 2.2 | -56.7 -70.1 255 25 13 3.4 1.9 38000 -53.1 -63.6 290 23 12 5.9 3.2 | -53.1 -63.6 260 29 15 6.2 3.4 36000 -49.6 -57.3 285 28 14 5.9 3.2 | -49.4 -56.9 270 34 17 6.2 3.4 34000 -45.5 -49.9 285 29 15 7.4 4.1 | -45.4 -49.7 270 36 18 7.2 4.0 32000 -41.1 -42.0 280 26 14 7.4 4.1 | -41.0 -41.8 275 35 18 7.2 4.0 30000 -36.4 -33.5 280 26 13 8.0 4.4 | -36.6 -33.9 275 34 18 7.6 4.2 29000 -34.0 -29.2 280 26 14 8.0 4.4 | -34.3 -29.7 280 34 18 7.6 4.2 28000 -31.6 -24.9 280 27 14 8.0 4.4 | -32.0 -25.6 280 35 18 7.6 4.2 27000 -29.3 -20.7 280 28 14 7.2 4.0 | -29.7 -21.5 280 35 18 7.7 4.2 26000 -27.1 -16.8 280 29 15 7.3 4.0 | -27.4 -17.3 285 35 18 7.7 4.2 25000 -24.9 -12.8 285 30 15 7.3 4.0 | -24.5 -12.1 285 34 18 7.6 4.2 24000 -22.4 -8.3 285 30 16 6.2 3.4 | -22.7 -8.9 290 34 17 4.8 2.6 23000 -20.5 -4.9 285 30 16 6.2 3.4 | -21.3 -6.3 290 33 17 4.8 2.6 22000 -18.6 -1.5 285 30 16 6.2 3.4 | -19.9 -3.8 290 31 16 4.9 2.7 21000 -16.9 1.6 285 29 15 5.6 3.0 | -18.0 -0.4 290 30 15 7.4 4.1 20000 -15.3 4.5 285 27 14 5.6 3.1 | -15.8 3.6 290 28 14 7.5 4.1 19500 -14.5 5.9 285 26 13 5.7 3.1 | -14.7 5.5 285 27 14 7.6 4.1 19000 -13.7 7.3 285 25 13 6.1 3.3 | -13.6 7.5 285 26 13 8.0 4.4 18500 -12.7 9.1 280 24 12 6.9 3.8 | -12.4 9.7 285 25 13 8.9 4.9 18000 -11.7 10.9 280 23 12 6.8 3.7 | -11.1 12.0 285 24 13 8.8 4.8 17500 -10.6 12.9 280 22 11 8.4 4.6 | -9.8 14.4 285 24 12 9.2 5.0 17000 -9.3 15.3 275 22 11 8.5 4.7 | -8.4 16.9 280 23 12 9.2 5.1 16500 -8.1 17.4 275 21 11 8.6 4.7 | -7.0 19.4 280 23 12 9.2 5.1 16000 -6.8 19.8 275 21 11 8.8 4.8 | -5.6 21.9 280 22 12 9.3 5.1 15500 -5.5 22.1 275 20 10 8.8 4.8 | -4.2 24.4 280 22 11 9.3 5.1 15000 -4.2 24.4 270 20 10 9.1 5.0 | -2.8 27.0 275 22 11 9.6 5.3 14500 -2.8 27.0 270 20 10 9.0 5.0 | -1.4 29.5 275 21 11 9.6 5.3 14000 -1.5 29.3 270 19 10 9.2 5.0 | 0.0 32.0 275 21 11 9.4 5.2 13500 -0.1 31.8 270 19 10 9.2 5.0 | 1.4 34.5 275 21 11 9.4 5.2 13000 1.3 34.3 265 19 10 9.2 5.1 | 2.9 37.2 270 21 11 9.5 5.2 12500 2.6 36.7 265 19 10 9.2 5.1 | 4.3 39.7 270 21 11 9.5 5.2 12000 4.0 39.2 265 19 10 9.3 5.1 | 5.7 42.3 270 20 10 9.4 5.2 11500 5.4 41.7 265 19 10 9.4 5.1 | 7.1 44.8 265 20 10 9.4 5.1 11000 6.8 44.2 265 19 10 8.5 4.7 | 8.5 47.3 265 20 10 8.7 4.7 10500 8.0 46.4 260 18 9 7.4 4.1 | 9.7 49.5 265 19 10 8.0 4.4 10250 8.6 47.5 260 18 9 11.8 6.5 | 10.4 50.7 265 19 10 11.8 6.5 10000 9.6 49.3 260 18 9 12.1 6.6 | 11.4 52.5 265 19 10 11.5 6.3 9750 10.3 50.5 260 18 9 8.5 4.6 | 12.0 53.6 265 19 10 8.4 4.6 9500 11.0 51.8 260 18 9 9.0 5.0 | 12.7 54.9 260 18 9 9.0 4.9 9250 11.7 53.1 260 17 9 10.3 5.7 | 13.4 56.1 260 18 9 9.8 5.4 9000 12.5 54.5 260 17 9 10.9 6.0 | 14.2 57.6 260 17 9 10.4 5.7 8750 13.3 55.9 260 17 9 9.6 5.3 | 14.9 58.8 260 17 9 9.6 5.3 8500 14.8 58.6 260 17 9 9.0 4.9 | 16.4 61.5 260 17 9 9.2 5.0 8250 15.4 59.7 260 17 9 9.0 4.9 | 17.0 62.6 260 17 9 9.1 5.0 8000 16.2 61.2 260 17 9 10.6 5.8 | 17.8 64.0 260 16 8 10.1 5.5 7750 17.0 62.6 260 16 8 11.2 6.1 | 18.5 65.3 260 16 8 10.4 5.7 7500 17.8 64.0 260 16 8 9.4 5.2 | 19.3 66.7 260 15 8 9.4 5.2 7250 18.4 65.1 260 16 8 7.8 4.3 | 19.9 67.8 260 16 8 8.3 4.6 7000 19.0 66.2 260 16 8 10.4 5.7 | 20.6 69.1 260 15 8 9.8 5.4 6750 19.9 67.8 260 15 8 11.8 6.5 | 21.4 70.5 255 15 8 10.9 6.0 6500 20.7 69.3 260 15 8 11.0 6.1 | 22.2 72.0 255 14 7 10.4 5.7 6250 21.6 70.9 260 15 8 11.5 6.3 | 23.0 73.4 255 14 7 10.6 5.8 6000 22.4 72.3 265 15 8 8.5 4.6 | 23.7 74.7 255 14 7 8.6 4.7 5750 23.0 73.4 260 14 7 13.6 7.5 | 24.3 75.7 255 13 7 10.3 5.6 5500 26.1 79.0 265 13 6 87.7 48.1 | 26.1 79.0 255 11 6 49.0 26.9 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