Soaring Guidance
Issued by NWS Grand Junction, CO
Issued by NWS Grand Junction, CO
868 UXUS97 KGJT 111307 SRGGJT Soaring Forecast National Weather Service Grand Junction, Colorado 707 AM MDT Sunday, August 11, 2024 This forecast is for Sunday, August 11, 2024: If the trigger temperature of 79.9 F/26.6 C is reached...then Thermal Soaring Index....................... Excellent Maximum rate of lift........................ 926 ft/min (4.7 m/s) Maximum height of thermals.................. 13925 ft MSL (9086 ft AGL) Forecast maximum temperature................... 89.0 F/32.1 C Time of trigger temperature.................... 1100 MDT Time of overdevelopment........................ 1700 MDT Middle/high clouds during soaring window....... None Surface winds during soaring window............ 20 mph or less Height of the -3 thermal index................. 11427 ft MSL (6588 ft AGL) Thermal soaring outlook for Monday 08/12....... Excellent Wave Soaring Index............................. Not available Remarks... Sunrise/Sunset.................... 06:24:32 / 20:13:56 MDT Total possible sunshine........... 13 hr 49 min 24 sec (829 min 24 sec) Altitude of sun at 13:19:14 MDT... 65.46 degrees Upper air data from rawinsonde observation taken on 08/11/2024 at 0600 MDT Freezing level.................. 16078 ft MSL (11239 ft AGL) Convective condensation level... 13646 ft MSL (8807 ft AGL) Lifted condensation level....... 13775 ft MSL (8935 ft AGL) Lifted index.................... -3.2 K index......................... +30.4 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 -88.2 270 36 19 5.0 2.7 81.6 178.9 29.1 M M 45000 -60.2 -76.4 285 53 27 4.4 2.4 68.4 155.1 22.9 M M 40000 -50.8 -59.4 260 51 26 9.4 5.1 60.1 140.2 19.0 M M 38000 -44.7 -48.5 265 51 26 8.1 4.5 59.3 138.8 19.0 M M 36000 -40.4 -40.7 270 51 26 9.5 5.2 57.2 134.9 18.0 M M 34000 -35.4 -31.7 270 54 28 8.6 4.7 55.9 132.6 17.5 M M 32000 -30.9 -23.6 265 46 24 6.4 3.5 54.1 129.4 16.6 M M 30000 -27.1 -16.8 265 49 25 5.2 2.9 51.4 124.6 14.9 M M 29000 -25.3 -13.5 270 45 23 5.7 3.1 49.8 121.7 13.9 M M 28000 -23.6 -10.5 260 39 20 5.9 3.2 48.3 118.9 12.8 M M 27000 -21.9 -7.4 270 36 19 7.7 4.2 46.8 116.3 11.7 M M 26000 -19.2 -2.6 270 36 18 9.1 5.0 46.6 115.8 11.6 M M 25000 -17.0 1.4 270 31 16 5.6 3.1 45.7 114.2 11.0 M M 24000 -16.0 3.2 260 31 16 5.4 2.9 43.4 110.1 9.2 M M 23000 -13.8 7.2 260 24 12 7.3 4.0 42.4 108.4 8.6 M M 22000 -12.1 10.2 270 26 13 6.7 3.7 41.0 105.8 7.4 M M 21000 -10.0 14.0 290 30 16 6.0 3.3 40.1 104.2 6.7 M M 20000 -7.4 18.7 305 31 16 3.1 1.7 38.8 101.9 5.7 M M 19500 -6.7 19.9 310 32 16 4.8 2.6 38.0 100.5 5.0 M M 19000 -6.3 20.7 300 26 13 4.7 2.6 36.9 98.4 3.9 M M 18500 -5.4 22.3 290 21 11 6.2 3.4 36.3 97.3 3.4 M M 18000 -4.5 23.9 275 18 9 6.2 3.4 35.7 96.2 2.9 M M 17500 -3.4 25.9 275 18 9 8.1 4.5 35.2 95.4 2.5 M M 17000 -2.2 28.0 260 14 7 8.9 4.9 35.0 94.9 2.2 M M 16500 -0.9 30.4 260 15 8 9.2 5.1 34.9 94.8 2.1 M M 16000 0.4 32.7 265 17 9 9.0 4.9 34.8 94.6 1.9 M M 15500 1.6 34.9 260 19 10 7.7 4.2 34.6 94.3 1.7 M M 15000 2.5 36.5 260 21 11 5.5 3.0 34.0 93.2 1.1 M M 14500 3.3 37.9 255 23 12 5.3 2.9 33.3 92.0 0.5 M M 14000 4.3 39.7 255 26 13 8.9 4.9 32.8 91.1 0.0 M M 13500 5.6 42.1 255 26 13 8.0 4.4 32.8 91.0 -0.1 676 3.4 13000 6.1 43.0 250 25 13 3.6 2.0 31.8 89.2 -1.1 645 3.3 12500 7.0 44.6 255 25 13 7.0 3.9 31.3 88.3 -1.6 603 3.1 12000 8.1 46.6 255 27 14 6.9 3.8 30.8 87.5 -2.1 558 2.8 11500 8.7 47.7 255 26 13 4.3 2.4 30.1 86.1 -2.9 524 2.7 11000 9.8 49.6 255 26 13 8.9 4.9 29.7 85.4 -3.3 477 2.4 10500 11.1 52.0 250 26 13 8.0 4.4 29.5 85.2 -3.5 423 2.1 10250 11.6 52.9 250 25 13 6.9 3.8 29.3 84.8 -3.7 400 2.0 10000 12.1 53.8 250 24 12 7.2 4.0 29.1 84.4 -3.9 378 1.9 9750 12.6 54.7 245 21 11 7.3 4.0 28.9 84.1 -4.1 354 1.8 9500 13.2 55.8 245 19 10 7.3 4.0 28.7 83.7 -4.3 331 1.7 9250 13.7 56.7 240 16 8 7.3 4.0 28.6 83.4 -4.5 307 1.6 9000 14.2 57.6 230 13 7 7.3 4.0 28.4 83.1 -4.7 284 1.4 8750 14.8 58.6 225 14 7 7.3 4.0 28.2 82.8 -4.9 260 1.3 8500 15.3 59.5 215 14 7 7.3 4.0 28.0 82.4 -5.1 237 1.2 8250 15.9 60.6 200 14 7 7.3 4.0 27.8 82.1 -5.3 213 1.1 8000 16.4 61.5 185 15 8 7.3 4.0 27.6 81.7 -5.5 189 1.0 7750 16.9 62.4 185 16 8 7.3 4.0 27.4 81.4 -5.7 166 0.8 7500 17.5 63.5 170 17 9 7.3 4.0 27.2 81.0 -6.0 142 0.7 7250 18.0 64.4 160 19 10 7.6 4.2 27.1 80.7 -6.2 119 0.6 7000 18.5 65.3 160 21 11 6.4 3.5 26.9 80.4 -6.4 95 0.5 6750 19.0 66.2 160 22 11 6.7 3.7 26.6 79.8 -6.7 76 0.4 6500 19.4 66.9 160 24 13 2.0 1.1 26.3 79.3 -7.1 56 0.3 6250 19.1 66.4 160 24 13 -5.7 -3.1 25.3 77.6 -8.0 55 0.3 6000 18.8 65.8 160 23 12 0.6 0.3 24.3 75.7 -9.1 57 0.3 5750 19.1 66.4 155 20 10 0.9 0.5 23.8 74.8 -9.5 41 0.2 5500 19.1 66.4 150 17 9 0.5 0.3 22.9 73.2 -10.3 35 0.2 5250 19.4 66.9 140 14 7 9.1 5.0 22.6 72.7 -10.7 16 0.1 5000 20.1 68.2 135 12 6 7.3 4.0 22.6 72.6 -10.8 M M * * * * * * Numerical weather prediction model forecast data valid * * * * * * 08/11/2024 at 0900 MDT | 08/11/2024 at 1200 MDT | CAPE... +450.3 LI... -3.2 | CAPE... +761.5 LI... -4.5 CINH... -137.7 K Index... +31.0 | CINH... -43.4 K Index... +31.2 | 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 -64.8 -84.6 275 30 15 2.0 1.1 | -65.0 -85.0 275 28 14 1.5 0.8 45000 -59.2 -74.6 270 44 23 6.7 3.7 | -59.8 -75.6 265 42 21 6.8 3.7 40000 -49.1 -56.4 265 53 27 6.9 3.8 | -49.5 -57.1 260 48 25 7.3 4.0 38000 -44.5 -48.1 260 51 26 6.9 3.8 | -44.6 -48.3 260 49 25 7.3 4.0 36000 -40.3 -40.5 260 49 25 7.4 4.0 | -40.2 -40.4 255 50 26 7.7 4.2 34000 -35.7 -32.3 260 50 26 7.6 4.2 | -35.5 -31.9 255 49 25 7.8 4.3 32000 -31.1 -24.0 265 50 26 7.8 4.3 | -30.9 -23.6 260 47 24 7.8 4.3 30000 -27.6 -17.7 265 47 24 5.8 3.2 | -27.2 -17.0 260 44 23 6.1 3.3 29000 -25.9 -14.6 265 45 23 5.9 3.2 | -25.4 -13.7 265 42 22 6.1 3.3 28000 -24.2 -11.6 265 43 22 5.8 3.2 | -23.6 -10.5 265 40 21 5.1 2.8 27000 -22.5 -8.5 265 41 21 5.8 3.2 | -22.2 -8.0 265 39 20 5.1 2.8 26000 -20.7 -5.3 270 39 20 5.9 3.2 | -20.7 -5.3 270 38 19 5.1 2.8 25000 -19.0 -2.2 270 37 19 5.9 3.3 | -19.2 -2.6 270 36 19 5.4 2.9 24000 -16.7 1.9 275 34 17 6.3 3.4 | -17.4 0.7 275 34 18 6.3 3.5 23000 -14.8 5.4 280 32 16 6.3 3.4 | -15.1 4.8 280 31 16 6.4 3.5 22000 -12.9 8.8 285 30 16 7.0 3.8 | -13.1 8.4 285 30 15 7.2 3.9 21000 -10.8 12.6 290 29 15 7.1 3.9 | -11.0 12.2 285 28 14 7.2 4.0 20000 -8.8 16.2 290 28 15 7.2 3.9 | -8.9 16.0 290 26 14 7.2 4.0 19500 -7.7 18.1 295 28 14 7.4 4.1 | -7.9 17.8 290 26 13 7.5 4.1 19000 -6.6 20.1 295 27 14 7.8 4.3 | -6.8 19.8 290 25 13 7.7 4.2 18500 -5.5 22.1 295 26 13 7.8 4.3 | -5.6 21.9 285 24 12 7.8 4.3 18000 -4.4 24.1 290 24 13 7.4 4.1 | -4.5 23.9 285 23 12 7.6 4.2 17500 -3.3 26.1 290 23 12 7.4 4.1 | -3.4 25.9 280 22 11 7.6 4.2 17000 -2.3 27.9 290 22 11 7.6 4.2 | -2.3 27.9 280 21 11 7.8 4.3 16500 -1.2 29.8 285 21 11 7.8 4.3 | -1.1 30.0 280 21 11 7.9 4.4 16000 -0.0 32.0 285 20 10 7.8 4.3 | 0.0 32.0 275 20 10 8.0 4.4 15500 1.1 34.0 280 20 10 8.0 4.4 | 1.2 34.2 275 20 10 7.9 4.3 15000 2.2 36.0 280 20 10 8.0 4.4 | 2.3 36.1 275 19 10 7.9 4.3 14500 3.3 37.9 275 20 10 8.0 4.4 | 3.5 38.3 275 19 10 8.0 4.4 14000 4.5 40.1 275 21 11 8.0 4.4 | 4.6 40.3 275 19 10 8.1 4.4 13500 5.6 42.1 270 22 11 8.0 4.4 | 5.8 42.4 270 19 10 8.3 4.5 13000 6.8 44.2 270 22 12 8.0 4.4 | 7.0 44.6 270 20 10 8.4 4.6 12500 7.9 46.2 265 23 12 7.8 4.3 | 8.2 46.8 270 20 10 8.3 4.5 12000 9.0 48.2 265 23 12 7.4 4.0 | 9.3 48.7 270 19 10 8.1 4.5 11500 10.1 50.2 265 24 12 7.1 3.9 | 10.4 50.7 270 19 10 7.8 4.3 11000 10.9 51.6 260 23 12 5.8 3.2 | 11.4 52.5 265 18 9 6.9 3.8 10500 11.7 53.1 260 22 12 4.8 2.6 | 12.4 54.3 265 17 9 5.5 3.0 10250 12.0 53.6 260 22 11 4.7 2.6 | 12.7 54.9 260 17 9 5.5 3.0 10000 12.4 54.3 255 20 11 6.3 3.5 | 13.2 55.8 260 16 8 7.4 4.0 9750 12.9 55.2 250 19 10 6.0 3.3 | 13.7 56.7 260 15 8 6.8 3.7 9500 13.3 55.9 250 18 9 6.6 3.6 | 14.2 57.6 255 14 7 7.2 3.9 9250 13.8 56.8 245 17 9 7.5 4.1 | 14.7 58.5 255 13 7 7.4 4.1 9000 14.3 57.7 245 16 8 6.1 3.4 | 15.2 59.4 255 12 6 7.1 3.9 8750 14.7 58.5 240 14 7 4.7 2.6 | 15.7 60.3 250 11 6 6.9 3.8 8500 15.5 59.9 230 12 6 7.1 3.9 | 16.2 61.2 250 10 5 6.9 3.8 8250 16.0 60.8 230 11 6 6.3 3.5 | 17.1 62.8 250 8 4 7.8 4.3 8000 16.4 61.5 220 10 5 4.9 2.7 | 17.8 64.0 250 8 4 10.1 5.5 7750 16.7 62.1 210 9 5 5.1 2.8 | 18.5 65.3 245 7 4 8.4 4.6 7500 17.1 62.8 205 9 5 5.5 3.0 | 19.0 66.2 245 6 3 6.7 3.7 7250 17.5 63.5 195 9 4 5.5 3.0 | 19.5 67.1 245 5 3 8.2 4.5 7000 17.9 64.2 190 8 4 6.2 3.4 | 20.2 68.4 240 5 2 11.1 6.1 6750 18.4 65.1 185 8 4 6.6 3.6 | 21.0 69.8 235 5 2 10.3 5.6 6500 18.8 65.8 175 8 4 6.6 3.6 | 21.7 71.1 240 4 2 8.8 4.8 6250 19.3 66.7 165 8 4 6.4 3.5 | 22.4 72.3 245 3 2 8.5 4.7 6000 19.8 67.6 160 7 4 9.2 5.0 | 23.1 73.6 245 3 2 13.5 7.4 5750 20.7 69.3 160 6 3 14.4 7.9 | 24.5 76.1 240 3 2 24.7 13.5 5500 21.5 70.7 150 5 3 4.3 2.4 | 25.9 78.6 255 2 1 5.3 2.9 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 08/11/2024 at 1500 MDT | 08/11/2024 at 1800 MDT | CAPE... +751.8 LI... -3.8 | CAPE... +841.7 LI... -3.9 CINH... -14.1 K Index... +30.5 | CINH... -57.8 K Index... +33.2 | 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 -64.7 -84.5 270 28 14 1.2 0.6 | -64.7 -84.5 265 26 13 0.8 0.5 45000 -59.7 -75.5 265 41 21 7.0 3.8 | -60.3 -76.5 265 41 21 6.7 3.7 40000 -48.7 -55.7 260 45 23 7.0 3.8 | -49.5 -57.1 265 48 24 7.4 4.1 38000 -44.5 -48.1 260 48 25 7.0 3.8 | -45.1 -49.2 265 49 25 7.4 4.1 36000 -40.2 -40.4 255 51 26 7.2 4.0 | -40.6 -41.1 265 49 25 7.6 4.2 34000 -35.8 -32.4 260 48 25 7.3 4.0 | -36.0 -32.8 270 46 24 7.7 4.2 32000 -31.4 -24.5 260 46 24 7.6 4.2 | -31.4 -24.5 270 43 22 8.3 4.6 30000 -27.5 -17.5 260 42 21 6.5 3.6 | -27.3 -17.1 270 37 19 6.8 3.8 29000 -25.6 -14.1 260 39 20 6.5 3.6 | -25.3 -13.5 270 34 18 6.9 3.8 28000 -23.7 -10.7 260 37 19 5.8 3.2 | -23.3 -9.9 270 32 16 6.6 3.6 27000 -22.0 -7.6 265 36 18 5.7 3.1 | -21.3 -6.3 270 30 16 6.6 3.6 26000 -20.3 -4.5 265 34 17 5.8 3.2 | -19.4 -2.9 270 29 15 6.6 3.6 25000 -18.6 -1.5 270 32 17 5.9 3.2 | -17.4 0.7 265 27 14 6.5 3.6 24000 -16.3 2.7 275 31 16 6.4 3.5 | -15.2 4.6 265 25 13 5.9 3.2 23000 -14.5 5.9 280 29 15 6.4 3.5 | -13.5 7.7 265 23 12 5.9 3.3 22000 -12.6 9.3 280 28 15 6.9 3.8 | -11.8 10.8 265 22 11 6.2 3.4 21000 -10.5 13.1 285 26 13 7.0 3.8 | -10.0 14.0 260 19 10 6.2 3.4 20000 -8.5 16.7 285 24 12 7.0 3.9 | -8.1 17.4 255 16 8 6.2 3.4 19500 -7.5 18.5 285 23 12 7.4 4.1 | -7.2 19.0 255 15 7 6.6 3.6 19000 -6.4 20.5 285 22 11 7.9 4.3 | -6.2 20.8 250 14 7 7.2 4.0 18500 -5.2 22.6 285 21 11 7.9 4.3 | -5.2 22.6 250 13 7 7.3 4.0 18000 -4.0 24.8 285 20 10 8.0 4.4 | -4.1 24.6 250 13 7 7.3 4.0 17500 -2.9 26.8 285 19 10 8.0 4.4 | -3.1 26.4 250 12 6 7.3 4.0 17000 -1.7 28.9 285 18 9 7.9 4.4 | -2.0 28.4 250 12 6 7.4 4.0 16500 -0.6 30.9 280 17 9 7.9 4.3 | -1.0 30.2 250 12 6 7.4 4.0 16000 0.6 33.1 280 16 8 7.9 4.3 | 0.1 32.2 250 12 6 7.3 4.0 15500 1.7 35.1 280 15 8 8.2 4.5 | 1.2 34.2 250 12 6 8.2 4.5 15000 2.9 37.2 275 15 8 8.2 4.5 | 2.4 36.3 255 12 6 8.1 4.5 14500 4.1 39.4 275 15 8 8.4 4.6 | 3.6 38.5 255 13 7 8.3 4.6 14000 5.3 41.5 270 15 8 8.4 4.6 | 4.8 40.6 260 13 7 8.4 4.6 13500 6.5 43.7 270 15 8 8.4 4.6 | 6.0 42.8 260 14 7 8.5 4.7 13000 7.7 45.9 270 15 8 8.4 4.6 | 7.2 45.0 260 14 7 8.7 4.8 12500 8.9 48.0 270 15 8 8.6 4.7 | 8.5 47.3 265 14 7 8.7 4.8 12000 10.2 50.4 265 14 7 8.9 4.9 | 9.7 49.5 265 14 7 8.6 4.7 11500 11.5 52.7 265 14 7 8.9 4.9 | 11.0 51.8 265 14 7 8.6 4.7 11000 12.8 55.0 265 14 7 8.7 4.8 | 12.2 54.0 265 15 8 8.4 4.6 10500 14.1 57.4 265 14 7 7.1 3.9 | 13.5 56.3 270 15 8 5.8 3.2 10250 14.5 58.1 265 14 7 7.4 4.0 | 13.8 56.8 270 15 8 6.3 3.5 10000 15.2 59.4 265 13 7 9.8 5.4 | 14.5 58.1 270 15 8 10.3 5.7 9750 15.8 60.4 260 13 7 9.3 5.1 | 15.2 59.4 270 15 8 9.4 5.2 9500 16.5 61.7 260 12 6 9.0 5.0 | 15.9 60.6 275 16 8 9.0 5.0 9250 17.1 62.8 260 12 6 8.5 4.7 | 16.5 61.7 275 16 8 7.7 4.2 9000 17.7 63.9 260 11 6 8.9 4.9 | 17.0 62.6 280 16 8 8.0 4.4 8750 18.4 65.1 255 11 5 9.2 5.0 | 17.6 63.7 280 16 8 8.6 4.7 8500 19.7 67.5 255 10 5 8.3 4.6 | 18.3 64.9 280 16 8 8.0 4.4 8250 20.3 68.5 260 10 5 9.7 5.3 | 18.8 65.8 280 16 8 6.6 3.6 8000 21.1 70.0 255 10 5 11.6 6.4 | 20.0 68.0 285 17 9 10.4 5.7 7750 21.9 71.4 255 10 5 9.8 5.4 | 20.7 69.3 285 16 8 8.1 4.5 7500 22.6 72.7 255 10 5 7.8 4.3 | 21.1 70.0 290 17 9 5.4 2.9 7250 23.2 73.8 260 10 5 9.1 5.0 | 21.6 70.9 295 18 9 6.8 3.7 7000 24.0 75.2 260 10 5 12.1 6.7 | 22.2 72.0 295 17 9 10.8 5.9 6750 24.9 76.8 255 9 5 11.5 6.3 | 23.0 73.4 290 15 8 9.2 5.1 6500 25.7 78.3 260 9 5 10.4 5.7 | 23.5 74.3 295 16 8 6.2 3.4 6250 26.4 79.5 260 9 5 9.4 5.2 | 24.0 75.2 300 16 8 6.9 3.8 6000 27.2 81.0 260 9 5 13.5 7.4 | 24.5 76.1 300 16 8 10.3 5.7 5750 28.7 83.7 260 8 4 27.2 14.9 | 25.5 77.9 300 12 6 16.2 8.9 5500 30.7 87.3 265 8 4 19.9 10.9 | 26.3 79.3 305 13 7 1.4 0.8 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