Soaring Guidance
Issued by NWS Grand Junction, CO
Issued by NWS Grand Junction, CO
138 UXUS97 KGJT 151306 SRGGJT Soaring Forecast National Weather Service Grand Junction, Colorado 706 AM MDT Thursday, August 15, 2024 This forecast is for Thursday, August 15, 2024: If the trigger temperature of 83.3 F/28.5 C is reached...then Thermal Soaring Index....................... Excellent Maximum rate of lift........................ 1270 ft/min (6.5 m/s) Maximum height of thermals.................. 18385 ft MSL (13546 ft AGL) Forecast maximum temperature................... 92.0 F/33.8 C Time of trigger temperature.................... 1145 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................. 12391 ft MSL (7551 ft AGL) Thermal soaring outlook for Friday 08/16....... Excellent Wave Soaring Index............................. Not available Remarks... Sunrise/Sunset.................... 06:28:11 / 20:08:46 MDT Total possible sunshine........... 13 hr 40 min 34 sec (820 min 34 sec) Altitude of sun at 13:18:28 MDT... 64.27 degrees Upper air data from rawinsonde observation taken on 08/15/2024 at 0600 MDT Freezing level.................. 15082 ft MSL (10243 ft AGL) Convective condensation level... 14735 ft MSL (9896 ft AGL) Lifted condensation level....... 15887 ft MSL (11047 ft AGL) Lifted index.................... -2.0 K index......................... +24.7 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 -64.6 -84.3 270 35 18 -3.1 -1.7 85.6 186.0 30.4 M M 45000 -59.2 -74.6 260 47 24 7.0 3.9 70.1 158.1 22.9 M M 40000 -49.4 -56.9 270 58 30 6.5 3.6 62.5 144.4 19.4 M M 38000 -46.2 -51.2 275 58 30 3.8 2.1 58.5 137.4 17.3 M M 36000 -42.9 -45.2 275 57 30 8.6 4.7 54.9 130.8 15.1 M M 34000 -37.9 -36.2 280 58 30 7.8 4.3 52.8 127.0 14.0 M M 32000 -33.8 -28.8 280 55 29 9.1 5.0 50.3 122.5 12.6 M M 30000 -29.4 -20.9 285 44 23 6.6 3.6 48.4 119.0 11.4 M M 29000 -27.7 -17.9 285 43 22 9.9 5.4 46.8 116.2 10.3 M M 28000 -25.6 -14.1 285 42 22 8.7 4.8 45.7 114.2 9.6 M M 27000 -23.0 -9.4 285 41 21 7.9 4.4 45.3 113.5 9.4 M M 26000 -20.7 -5.3 285 44 23 7.8 4.3 44.4 112.0 8.8 M M 25000 -18.7 -1.7 285 45 23 6.4 3.5 43.3 110.0 8.0 M M 24000 -16.6 2.1 285 44 23 7.0 3.8 42.3 108.1 7.2 M M 23000 -14.5 5.9 285 46 24 7.2 4.0 41.3 106.3 6.5 M M 22000 -12.4 9.7 275 41 21 7.3 4.0 40.4 104.7 5.8 M M 21000 -10.1 13.8 275 41 21 7.8 4.3 39.6 103.3 5.2 M M 20000 -7.8 18.0 285 32 16 7.8 4.3 38.9 102.0 4.7 M M 19500 -6.6 20.1 285 29 15 8.3 4.5 38.6 101.4 4.5 M M 19000 -5.7 21.7 275 24 12 5.5 3.0 37.9 100.3 3.9 M M 18500 -7.4 18.7 280 17 9 -4.8 -2.6 33.5 92.4 -0.0 1271 6.5 18000 -6.6 20.1 300 12 6 8.1 4.4 32.9 91.2 -0.6 1230 6.3 17500 -5.2 22.6 295 13 7 8.9 4.9 32.8 91.1 -0.7 1173 6.0 17000 -3.8 25.2 280 15 8 9.6 5.3 32.7 90.9 -0.8 1118 5.7 16500 -2.9 26.8 280 15 8 3.8 2.1 32.2 90.0 -1.3 1075 5.5 16000 -2.3 27.9 265 17 9 6.9 3.8 31.4 88.5 -2.2 1042 5.3 15500 -1.0 30.2 260 19 10 9.8 5.4 31.3 88.3 -2.4 989 5.0 15000 0.4 32.7 265 20 10 10.1 5.5 31.3 88.3 -2.5 931 4.7 14500 1.9 35.4 270 19 10 10.0 5.5 31.4 88.5 -2.4 872 4.4 14000 3.4 38.1 260 15 8 10.0 5.5 31.4 88.5 -2.4 813 4.1 13500 4.9 40.8 260 17 9 10.0 5.5 31.4 88.6 -2.5 754 3.8 13000 6.3 43.3 260 18 9 8.7 4.8 31.5 88.6 -2.5 696 3.5 12500 7.3 45.1 250 16 8 8.0 4.4 31.1 88.1 -2.9 650 3.3 12000 8.6 47.5 245 15 8 9.8 5.4 31.0 87.8 -3.1 597 3.0 11500 10.0 50.0 245 14 7 9.6 5.3 31.0 87.8 -3.2 540 2.7 11000 11.5 52.7 230 14 7 9.3 5.1 31.0 87.7 -3.2 482 2.4 10500 12.6 54.7 220 12 6 8.6 4.7 30.7 87.3 -3.6 434 2.2 10250 13.2 55.8 220 9 5 8.6 4.7 30.7 87.2 -3.7 407 2.1 10000 13.8 56.8 220 9 5 7.3 4.0 30.5 86.9 -3.8 382 1.9 9750 14.4 57.9 220 7 4 7.6 4.2 30.3 86.6 -4.0 358 1.8 9500 15.0 59.0 200 9 5 7.6 4.1 30.2 86.3 -4.2 333 1.7 9250 15.5 59.9 200 12 6 7.5 4.1 30.0 86.0 -4.3 308 1.6 9000 16.1 61.0 190 15 8 7.7 4.2 29.8 85.7 -4.5 284 1.4 8750 16.7 62.1 175 17 9 7.1 3.9 29.6 85.4 -4.7 259 1.3 8500 17.1 62.8 170 18 9 4.9 2.7 29.3 84.8 -5.0 239 1.2 8250 17.4 63.3 160 20 10 4.1 2.2 28.9 84.0 -5.4 223 1.1 8000 17.7 63.9 155 22 11 4.0 2.2 28.5 83.3 -5.9 207 1.1 7750 18.0 64.4 155 22 11 5.2 2.8 28.1 82.5 -6.4 191 1.0 7500 18.3 64.9 155 22 11 4.7 2.6 27.7 81.9 -6.7 172 0.9 7250 18.5 65.3 155 22 11 -2.0 -1.1 27.1 80.8 -7.4 161 0.8 7000 18.1 64.6 160 21 11 -5.0 -2.8 26.0 78.8 -8.5 164 0.8 6750 17.8 64.0 155 20 10 -5.0 -2.8 24.9 76.9 -9.6 167 0.9 6500 17.4 63.3 145 18 9 -2.0 -1.1 23.8 74.9 -10.7 171 0.9 6250 17.6 63.7 135 17 9 6.3 3.5 23.3 73.9 -11.2 158 0.8 6000 18.2 64.8 120 18 9 9.1 5.0 23.2 73.7 -11.4 132 0.7 5750 18.8 65.8 105 19 10 8.9 4.9 23.1 73.6 -11.5 106 0.5 5500 19.5 67.1 095 19 10 7.8 4.3 23.0 73.5 -11.6 79 0.4 5250 19.9 67.8 090 19 10 5.4 3.0 22.8 73.0 -11.9 59 0.3 5000 20.1 68.2 085 18 9 1.5 0.8 22.3 72.2 -12.5 45 0.2 * * * * * * Numerical weather prediction model forecast data valid * * * * * * 08/15/2024 at 0900 MDT | 08/15/2024 at 1200 MDT | CAPE... +21.4 LI... +0.7 | CAPE... +160.6 LI... -0.2 CINH... -93.4 K Index... +24.1 | CINH... -9.4 K Index... +25.8 | 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 -62.6 -80.7 280 26 14 2.0 1.1 | -62.3 -80.1 275 22 11 1.7 1.0 45000 -57.9 -72.2 270 41 21 5.4 3.0 | -57.8 -72.0 270 38 20 5.4 3.0 40000 -49.7 -57.5 270 52 27 6.1 3.4 | -49.6 -57.3 265 54 28 6.3 3.4 38000 -45.5 -49.9 270 53 27 6.1 3.4 | -45.3 -49.5 265 56 29 6.3 3.5 36000 -41.9 -43.4 270 53 27 6.1 3.4 | -41.5 -42.7 265 58 30 6.1 3.3 34000 -38.2 -36.8 275 51 26 6.1 3.3 | -38.1 -36.6 270 55 28 5.7 3.1 32000 -34.6 -30.3 280 48 25 6.1 3.3 | -34.7 -30.5 275 52 27 5.7 3.1 30000 -30.4 -22.7 280 42 21 7.1 3.9 | -30.6 -23.1 275 45 23 7.1 3.9 29000 -28.3 -18.9 280 38 20 7.1 3.9 | -28.4 -19.1 275 41 21 7.1 3.9 28000 -26.2 -15.2 280 35 18 7.8 4.3 | -26.3 -15.3 275 37 19 7.7 4.2 27000 -23.8 -10.8 280 35 18 8.0 4.4 | -23.9 -11.0 270 36 18 7.9 4.3 26000 -21.4 -6.5 280 35 18 8.0 4.4 | -21.6 -6.9 270 34 18 7.9 4.3 25000 -19.0 -2.2 280 35 18 8.0 4.4 | -19.2 -2.6 265 33 17 7.9 4.3 24000 -16.7 1.9 275 35 18 7.7 4.2 | -16.9 1.6 265 33 17 7.9 4.4 23000 -13.8 7.2 275 35 18 7.7 4.2 | -13.9 7.0 265 33 17 8.0 4.4 22000 -11.6 11.1 275 35 18 5.9 3.2 | -11.6 11.1 265 33 17 6.1 3.4 21000 -9.9 14.2 270 31 16 5.5 3.0 | -9.9 14.2 265 30 15 5.7 3.1 20000 -8.3 17.1 270 27 14 5.5 3.0 | -8.2 17.2 260 27 14 5.7 3.1 19500 -7.5 18.5 270 25 13 5.2 2.9 | -7.4 18.7 255 25 13 5.2 2.9 19000 -6.9 19.6 265 23 12 4.3 2.3 | -6.8 19.8 255 23 12 3.7 2.1 18500 -6.3 20.7 265 21 11 4.3 2.4 | -6.3 20.7 250 21 11 3.8 2.1 18000 -5.6 21.9 265 19 10 4.8 2.6 | -5.7 21.7 245 20 10 5.4 2.9 17500 -5.0 23.0 260 17 9 5.0 2.7 | -4.9 23.2 240 19 10 5.7 3.1 17000 -4.3 24.3 260 15 8 5.9 3.2 | -4.2 24.4 235 18 9 6.3 3.4 16500 -3.3 26.1 260 14 7 8.0 4.4 | -3.2 26.2 235 17 9 7.5 4.1 16000 -2.1 28.2 255 14 7 7.9 4.4 | -2.1 28.2 235 17 9 7.3 4.0 15500 -1.0 30.2 255 14 7 8.9 4.9 | -0.9 30.4 235 17 9 9.0 5.0 15000 0.3 32.5 250 14 7 8.8 4.8 | 0.3 32.5 235 17 9 8.9 4.9 14500 1.5 34.7 250 15 7 9.1 5.0 | 1.6 34.9 235 17 9 9.1 5.0 14000 2.9 37.2 245 14 7 9.2 5.0 | 3.0 37.4 235 16 8 9.2 5.1 13500 4.2 39.6 245 14 7 9.1 5.0 | 4.3 39.7 235 16 8 9.3 5.1 13000 5.5 41.9 245 14 7 8.9 4.9 | 5.7 42.3 235 16 8 9.4 5.2 12500 6.8 44.2 240 14 7 8.9 4.9 | 7.1 44.8 235 16 8 9.3 5.1 12000 8.1 46.6 235 13 7 8.8 4.8 | 8.5 47.3 235 15 8 9.2 5.1 11500 9.4 48.9 235 13 6 8.8 4.8 | 9.8 49.6 235 14 7 9.2 5.0 11000 10.7 51.3 230 12 6 8.6 4.7 | 11.2 52.2 235 14 7 9.0 5.0 10500 12.0 53.6 225 12 6 6.9 3.8 | 12.5 54.5 235 13 7 6.8 3.8 10250 12.4 54.3 220 12 6 7.0 3.8 | 12.9 55.2 235 12 6 7.4 4.1 10000 13.1 55.6 215 11 6 9.4 5.1 | 13.7 56.7 230 12 6 10.8 5.9 9750 13.7 56.7 210 11 6 8.8 4.8 | 14.4 57.9 230 11 6 10.1 5.5 9500 14.4 57.9 205 11 6 8.7 4.8 | 15.2 59.4 230 11 6 9.5 5.2 9250 15.0 59.0 205 11 6 8.0 4.4 | 15.8 60.4 230 10 5 8.3 4.6 9000 15.6 60.1 200 11 6 6.6 3.6 | 16.4 61.5 225 9 5 9.0 4.9 8750 16.0 60.8 190 11 6 5.9 3.2 | 17.1 62.8 225 9 5 9.7 5.3 8500 16.4 61.5 185 11 6 6.0 3.3 | 18.4 65.1 220 8 4 6.9 3.8 8250 17.3 63.1 175 12 6 5.7 3.1 | 18.9 66.0 215 7 3 8.8 4.8 8000 17.7 63.9 170 12 6 6.1 3.4 | 19.7 67.5 210 7 3 11.7 6.4 7750 18.1 64.6 165 11 5 4.8 2.6 | 20.5 68.9 210 7 4 9.7 5.3 7500 18.4 65.1 165 11 6 3.4 1.8 | 21.1 70.0 205 6 3 7.7 4.2 7250 18.7 65.7 160 11 6 4.1 2.2 | 21.7 71.1 205 6 3 9.2 5.0 7000 19.0 66.2 155 11 5 5.4 2.9 | 22.5 72.5 205 5 3 12.2 6.7 6750 19.4 66.9 150 9 4 4.8 2.7 | 23.4 74.1 205 6 3 11.4 6.3 6500 19.7 67.5 145 8 4 4.0 2.2 | 24.2 75.6 200 5 3 10.1 5.6 6250 20.0 68.0 140 7 4 3.7 2.0 | 25.0 77.0 195 5 2 9.1 5.0 6000 20.3 68.5 130 6 3 8.0 4.4 | 25.7 78.3 195 4 2 13.6 7.5 5750 21.2 70.2 125 5 3 16.5 9.1 | 27.2 81.0 200 4 2 27.6 15.2 5500 22.1 71.8 115 5 3 0.2 0.1 | 29.1 84.4 190 3 2 14.2 7.8 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 08/15/2024 at 1500 MDT | 08/15/2024 at 1800 MDT | CAPE... +146.7 LI... -0.3 | CAPE... +59.8 LI... 0.0 CINH... -27.2 K Index... +29.6 | CINH... -54.9 K Index... +27.6 | 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 -62.5 -80.5 275 23 12 1.8 1.0 | -62.2 -80.0 275 25 13 2.0 1.1 45000 -57.8 -72.0 270 41 21 5.6 3.1 | -57.4 -71.3 270 43 22 5.3 2.9 40000 -49.3 -56.7 260 58 30 6.1 3.4 | -48.9 -56.0 265 62 32 5.9 3.2 38000 -45.1 -49.2 260 60 31 6.1 3.4 | -45.3 -49.5 265 63 33 5.9 3.2 36000 -41.5 -42.7 260 62 32 5.9 3.2 | -41.8 -43.2 265 65 33 5.8 3.2 34000 -38.1 -36.6 265 59 30 5.5 3.0 | -38.4 -37.1 270 63 32 5.7 3.1 32000 -34.8 -30.6 270 56 29 5.6 3.1 | -34.9 -30.8 270 60 31 5.4 3.0 30000 -30.5 -22.9 270 49 25 7.4 4.0 | -30.5 -22.9 270 53 27 7.6 4.1 29000 -28.3 -18.9 270 45 23 7.4 4.0 | -28.3 -18.9 270 49 25 7.6 4.1 28000 -26.1 -15.0 265 41 21 7.3 4.0 | -26.0 -14.8 270 45 23 7.5 4.1 27000 -23.9 -11.0 265 39 20 7.3 4.0 | -23.8 -10.8 265 44 22 7.4 4.1 26000 -21.7 -7.1 260 38 19 7.3 4.0 | -21.5 -6.7 260 42 22 7.4 4.1 25000 -19.5 -3.1 255 36 19 7.4 4.1 | -19.3 -2.7 255 41 21 7.4 4.1 24000 -16.6 2.1 255 36 18 8.0 4.4 | -16.6 2.1 255 39 20 7.2 4.0 23000 -14.2 6.4 260 35 18 8.0 4.4 | -14.4 6.1 255 37 19 7.2 4.0 22000 -11.8 10.8 260 35 18 6.8 3.7 | -12.3 9.9 250 35 18 7.3 4.0 21000 -9.9 14.2 255 32 16 6.6 3.6 | -10.1 13.8 250 32 16 7.3 4.0 20000 -8.0 17.6 255 29 15 6.7 3.7 | -7.9 17.8 250 29 15 7.3 4.0 19500 -7.0 19.4 250 28 14 6.3 3.5 | -6.9 19.6 250 27 14 7.3 4.0 19000 -6.2 20.8 250 26 14 5.6 3.1 | -5.8 21.6 245 26 13 7.1 3.9 18500 -5.4 22.3 245 25 13 5.7 3.1 | -4.8 23.4 245 25 13 7.2 4.0 18000 -4.6 23.7 240 23 12 6.1 3.3 | -3.8 25.2 240 23 12 7.0 3.8 17500 -3.8 25.2 235 22 11 6.3 3.4 | -2.8 27.0 235 22 11 7.1 3.9 17000 -3.0 26.6 230 21 11 6.6 3.6 | -1.9 28.6 230 21 11 7.4 4.0 16500 -2.0 28.4 230 20 10 7.2 4.0 | -0.8 30.6 225 20 11 7.7 4.2 16000 -1.0 30.2 225 19 10 7.1 3.9 | 0.2 32.4 220 20 10 7.8 4.3 15500 0.1 32.2 225 17 9 8.9 4.9 | 1.4 34.5 220 19 10 8.9 4.9 15000 1.4 34.5 225 17 8 8.7 4.8 | 2.7 36.9 215 18 9 8.8 4.9 14500 2.7 36.9 225 16 8 9.0 5.0 | 3.9 39.0 215 17 9 9.2 5.0 14000 4.1 39.4 225 15 8 9.1 5.0 | 5.3 41.5 215 17 9 9.3 5.1 13500 5.4 41.7 225 14 7 9.4 5.1 | 6.7 44.1 220 16 8 9.3 5.1 13000 6.8 44.2 225 14 7 9.6 5.3 | 8.1 46.6 220 16 8 9.4 5.1 12500 8.3 46.9 225 14 7 9.6 5.3 | 9.5 49.1 220 15 8 9.3 5.1 12000 9.7 49.5 230 13 7 9.5 5.2 | 10.8 51.4 225 15 8 8.9 4.9 11500 11.1 52.0 230 13 6 9.4 5.2 | 12.2 54.0 225 14 7 8.9 4.9 11000 12.5 54.5 235 12 6 9.0 5.0 | 13.5 56.3 230 14 7 8.6 4.7 10500 13.8 56.8 235 11 6 7.7 4.2 | 14.7 58.5 230 13 7 10.2 5.6 10250 14.4 57.9 240 10 5 8.3 4.5 | 15.6 60.1 230 13 7 10.4 5.7 10000 15.1 59.2 240 10 5 10.6 5.8 | 16.2 61.2 235 13 7 8.5 4.6 9750 15.9 60.6 240 10 5 9.9 5.4 | 16.9 62.4 235 13 7 8.9 4.9 9500 16.6 61.9 240 10 5 10.2 5.6 | 17.5 63.5 240 13 6 9.0 4.9 9250 17.4 63.3 245 10 5 10.1 5.6 | 18.2 64.8 240 12 6 9.5 5.2 9000 18.1 64.6 245 10 5 9.7 5.3 | 18.9 66.0 245 12 6 9.1 5.0 8750 18.8 65.8 245 10 5 9.6 5.3 | 20.3 68.5 245 12 6 8.9 4.9 8500 20.2 68.4 245 10 5 8.4 4.6 | 20.9 69.6 250 12 6 8.5 4.6 8250 20.8 69.4 250 9 5 9.5 5.2 | 21.6 70.9 250 12 6 9.4 5.2 8000 21.6 70.9 250 9 5 11.1 6.1 | 22.3 72.1 250 12 6 10.6 5.8 7750 22.4 72.3 250 9 5 9.8 5.4 | 23.1 73.6 250 12 6 9.7 5.3 7500 23.1 73.6 250 9 5 8.5 4.7 | 23.8 74.8 250 12 6 8.3 4.6 7250 23.8 74.8 255 9 5 9.4 5.1 | 24.4 75.9 255 13 7 8.8 4.8 7000 24.5 76.1 255 9 5 11.5 6.3 | 25.1 77.2 255 12 6 10.9 6.0 6750 25.4 77.7 255 9 5 11.2 6.1 | 26.0 78.8 255 12 6 11.0 6.0 6500 26.2 79.2 255 9 4 10.5 5.8 | 26.7 80.1 255 12 6 10.3 5.7 6250 27.0 80.6 260 8 4 9.5 5.2 | 27.5 81.5 260 12 6 10.1 5.5 6000 27.7 81.9 260 8 4 12.2 6.7 | 28.2 82.8 260 12 6 9.9 5.4 5750 29.0 84.2 260 8 4 24.1 13.2 | 29.1 84.4 255 10 5 14.7 8.0 5500 31.0 87.8 265 7 4 25.8 14.1 | 30.7 87.3 265 10 5 30.4 16.7 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