Soaring Guidance
Issued by NWS Grand Junction, CO
Issued by NWS Grand Junction, CO
752 UXUS97 KGJT 221307 SRGGJT Soaring Forecast National Weather Service Grand Junction, Colorado 707 AM MDT Wednesday, May 22, 2024 This forecast is for Wednesday, May 22, 2024: If the trigger temperature of 58.4 F/14.7 C is reached...then Thermal Soaring Index....................... Excellent Maximum rate of lift........................ 1062 ft/min (5.4 m/s) Maximum height of thermals.................. 17897 ft MSL (13058 ft AGL) Forecast maximum temperature................... 77.0 F/25.5 C Time of trigger temperature.................... 1000 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................. 15129 ft MSL (10290 ft AGL) Thermal soaring outlook for Thursday 05/23..... Excellent Wave Soaring Index............................. Not available Remarks... Sunrise/Sunset.................... 05:54:53 / 20:26:53 MDT Total possible sunshine........... 14 hr 32 min 0 sec (872 min 0 sec) Altitude of sun at 13:10:53 MDT... 71.33 degrees Upper air data from rawinsonde observation taken on 05/22/2024 at 0600 MDT Freezing level.................. 10103 ft MSL (5264 ft AGL) Convective condensation level... 15390 ft MSL (10551 ft AGL) Lifted condensation level....... 16830 ft MSL (11990 ft AGL) Lifted index.................... -1.5 K index......................... -32.3 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 -55.3 -67.5 260 56 29 -6.2 -3.4 108.9 228.0 47.8 M M 45000 -51.5 -60.7 265 51 26 1.9 1.1 89.3 192.7 39.3 M M 40000 -55.2 -67.4 265 66 34 -6.1 -3.3 60.4 140.8 23.2 M M 38000 -57.7 -71.9 260 68 35 -1.3 -0.7 47.8 118.0 15.3 M M 36000 -56.5 -69.7 265 57 30 2.4 1.3 40.9 105.6 11.0 M M 34000 -53.3 -63.9 270 47 24 7.6 4.2 37.1 98.8 8.6 M M 32000 -48.7 -55.7 270 43 22 7.7 4.2 35.4 95.7 7.6 M M 30000 -42.9 -45.2 275 44 23 8.0 4.4 34.4 94.0 7.1 M M 29000 -40.5 -40.9 280 41 21 7.9 4.3 33.7 92.7 6.6 M M 28000 -38.0 -36.4 275 37 19 8.4 4.6 33.1 91.6 6.2 M M 27000 -35.5 -31.9 275 34 18 7.5 4.1 32.6 90.7 5.9 M M 26000 -33.3 -27.9 265 33 17 7.3 4.0 31.7 89.1 5.3 M M 25000 -31.1 -24.0 260 40 21 7.2 4.0 30.8 87.4 4.6 M M 24000 -29.0 -20.2 255 36 19 6.5 3.6 29.8 85.6 3.8 M M 23000 -26.8 -16.2 265 34 18 8.1 4.4 29.0 84.1 3.2 M M 22000 -24.3 -11.7 260 32 17 8.1 4.5 28.4 83.1 2.8 M M 21000 -21.9 -7.4 260 34 17 8.1 4.5 27.8 82.0 2.3 M M 20000 -19.5 -3.1 270 29 15 8.1 4.4 27.1 80.9 1.8 M M 19500 -18.3 -0.9 265 30 15 7.8 4.3 26.8 80.3 1.5 M M 19000 -17.1 1.2 265 27 14 7.7 4.2 26.4 79.6 1.2 M M 18500 -15.9 3.4 260 25 13 8.9 4.9 26.2 79.2 1.0 M M 18000 -15.0 5.0 250 24 12 2.9 1.6 25.5 77.9 0.4 M M 17500 -14.2 6.4 255 25 13 7.8 4.3 24.7 76.5 -0.3 1037 5.3 17000 -12.7 9.1 250 29 15 6.0 3.3 23.9 75.1 -0.9 969 4.9 16500 -11.8 10.8 260 29 15 6.0 3.3 23.3 74.0 -1.5 927 4.7 16000 -10.9 12.4 265 25 13 5.6 3.0 22.6 72.7 -2.1 886 4.5 15500 -10.1 13.8 265 28 14 6.0 3.3 21.9 71.5 -2.7 847 4.3 15000 -9.0 15.8 265 26 13 7.7 4.2 21.5 70.7 -3.2 800 4.1 14500 -8.0 17.6 265 23 12 5.9 3.2 21.0 69.9 -3.6 753 3.8 14000 -7.2 19.0 275 20 10 5.3 2.9 20.3 68.5 -4.3 715 3.6 13500 -6.4 20.5 275 17 9 5.3 2.9 19.6 67.2 -5.0 677 3.4 13000 -5.6 21.9 280 15 8 6.9 3.8 18.9 66.0 -5.6 638 3.2 12500 -4.4 24.1 275 12 6 6.8 3.7 18.6 65.4 -6.0 588 3.0 12000 -3.5 25.7 255 14 7 6.3 3.4 18.0 64.4 -6.5 546 2.8 11500 -2.6 27.3 250 12 6 6.3 3.5 17.4 63.4 -7.1 504 2.6 11000 -1.7 28.9 230 7 4 6.4 3.5 16.9 62.4 -7.7 462 2.3 10500 -0.8 30.6 220 9 4 6.5 3.6 16.4 61.5 -8.3 420 2.1 10250 -0.3 31.5 215 8 4 7.1 3.9 16.1 61.0 -8.6 398 2.0 10000 0.2 32.4 210 7 4 8.4 4.6 16.0 60.7 -8.8 375 1.9 9750 0.9 33.6 205 8 4 8.8 4.8 15.9 60.6 -8.9 348 1.8 9500 1.5 34.7 195 9 5 8.7 4.8 15.8 60.4 -9.1 322 1.6 9250 2.1 35.8 185 10 5 6.6 3.6 15.7 60.2 -9.2 297 1.5 9000 2.4 36.3 180 12 6 5.0 2.7 15.3 59.6 -9.6 279 1.4 8750 2.8 37.0 165 13 7 5.4 3.0 15.0 59.0 -10.0 260 1.3 8500 3.2 37.8 155 15 8 5.5 3.0 14.6 58.3 -10.4 241 1.2 8250 3.6 38.5 145 18 9 5.0 2.8 14.3 57.7 -10.8 223 1.1 8000 3.9 39.0 140 21 11 6.9 3.8 14.0 57.2 -11.1 204 1.0 7750 4.3 39.7 145 21 11 0.0 0.0 13.6 56.6 -11.5 186 0.9 7500 4.0 39.2 150 21 11 -1.5 -0.8 12.6 54.7 -12.6 187 1.0 7250 4.3 39.7 155 22 11 6.7 3.7 12.2 53.9 -13.1 172 0.9 7000 4.6 40.3 145 21 11 0.0 0.0 11.8 53.2 -13.6 156 0.8 6750 4.4 39.9 145 20 11 1.1 0.6 10.9 51.6 -14.5 153 0.8 6500 4.9 40.8 135 19 10 7.6 4.2 10.6 51.0 -14.8 132 0.7 6250 5.4 41.7 125 18 9 7.0 3.8 10.4 50.7 -15.0 109 0.6 6000 5.9 42.6 110 16 8 6.3 3.5 10.2 50.3 -15.3 86 0.4 5750 6.4 43.5 100 14 7 9.6 5.3 10.0 49.9 -15.5 63 0.3 5500 7.1 44.8 090 15 8 4.4 2.4 9.9 49.9 -15.6 35 0.2 5250 6.9 44.4 085 16 8 -5.6 -3.1 9.0 48.3 -16.6 33 0.2 5000 6.7 44.1 080 16 8 1.0 0.5 8.0 46.5 -17.6 35 0.2 * * * * * * Numerical weather prediction model forecast data valid * * * * * * 05/22/2024 at 0900 MDT | 05/22/2024 at 1200 MDT | CAPE... 0.0 LI... +5.8 | CAPE... 0.0 LI... +4.1 CINH... -0.1 K Index... -7.4 | CINH... -0.1 K Index... +4.4 | 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 -53.2 -63.8 255 43 22 0.4 0.2 | -53.5 -64.3 255 44 23 0.2 0.1 45000 -52.7 -62.9 260 51 26 -1.4 -0.8 | -53.2 -63.8 260 55 28 -1.2 -0.7 40000 -56.2 -69.2 255 62 32 -2.2 -1.2 | -56.2 -69.2 260 59 30 -1.9 -1.1 38000 -55.9 -68.6 255 60 31 2.2 1.2 | -55.9 -68.6 260 59 30 2.2 1.2 36000 -54.6 -66.3 260 53 27 2.2 1.2 | -54.6 -66.3 255 58 30 2.2 1.2 34000 -52.5 -62.5 260 48 25 7.9 4.3 | -52.5 -62.5 255 58 30 7.8 4.3 32000 -47.6 -53.7 260 48 25 8.0 4.4 | -47.7 -53.9 255 56 29 7.9 4.3 30000 -42.8 -45.0 260 48 25 7.7 4.2 | -43.0 -45.4 255 53 28 7.7 4.2 29000 -40.5 -40.9 260 46 24 7.7 4.2 | -40.7 -41.3 255 52 27 7.8 4.3 28000 -38.2 -36.8 255 44 23 7.7 4.2 | -38.3 -36.9 255 50 26 7.8 4.3 27000 -35.9 -32.6 255 42 22 7.7 4.2 | -36.0 -32.8 255 49 25 7.8 4.3 26000 -33.0 -27.4 255 41 21 7.6 4.2 | -33.1 -27.6 255 48 24 7.9 4.3 25000 -30.7 -23.3 255 40 21 7.6 4.2 | -30.7 -23.3 255 47 24 7.9 4.3 24000 -28.5 -19.3 255 39 20 7.8 4.3 | -28.4 -19.1 255 46 24 7.9 4.3 23000 -26.1 -15.0 255 37 19 7.8 4.3 | -26.0 -14.8 255 44 23 7.9 4.3 22000 -23.7 -10.7 255 36 18 7.8 4.3 | -23.6 -10.5 255 42 22 7.9 4.3 21000 -21.4 -6.5 255 34 18 7.3 4.0 | -21.3 -6.3 255 40 21 7.2 4.0 20000 -19.2 -2.6 255 32 17 7.4 4.0 | -19.1 -2.4 255 38 19 7.3 4.0 19500 -18.1 -0.6 255 31 16 7.4 4.0 | -18.0 -0.4 250 37 19 7.3 4.0 19000 -17.0 1.4 255 30 16 7.4 4.1 | -16.9 1.6 250 35 18 7.4 4.1 18500 -15.9 3.4 250 29 15 6.6 3.6 | -15.9 3.4 250 34 18 6.1 3.3 18000 -15.0 5.0 250 29 15 6.5 3.6 | -15.0 5.0 250 33 17 6.0 3.3 17500 -14.0 6.8 250 28 14 6.5 3.5 | -14.1 6.6 250 32 17 5.9 3.2 17000 -13.0 8.6 250 27 14 6.4 3.5 | -13.2 8.2 245 31 16 5.6 3.1 16500 -12.1 10.2 250 27 14 6.4 3.5 | -12.4 9.7 245 30 16 5.6 3.1 16000 -11.1 12.0 255 26 13 6.6 3.6 | -11.5 11.3 245 29 15 6.3 3.5 15500 -10.1 13.8 255 25 13 6.6 3.6 | -10.6 12.9 240 29 15 6.2 3.4 15000 -9.2 15.4 255 25 13 6.6 3.6 | -9.7 14.5 240 28 14 7.3 4.0 14500 -8.2 17.2 255 24 12 6.6 3.6 | -8.6 16.5 240 28 14 7.6 4.2 14000 -7.2 19.0 255 23 12 6.7 3.7 | -7.5 18.5 240 27 14 7.9 4.3 13500 -6.3 20.7 255 22 11 6.8 3.7 | -6.3 20.7 235 27 14 8.2 4.5 13000 -5.3 22.5 255 21 11 6.9 3.8 | -5.1 22.8 235 26 13 8.3 4.6 12500 -4.2 24.4 250 19 10 7.1 3.9 | -3.8 25.2 235 25 13 8.5 4.6 12000 -3.1 26.4 250 18 9 7.1 3.9 | -2.6 27.3 230 23 12 8.4 4.6 11500 -2.1 28.2 245 16 8 7.0 3.8 | -1.3 29.7 230 21 11 8.3 4.5 11000 -1.0 30.2 240 14 7 6.7 3.7 | -0.1 31.8 225 19 10 7.9 4.3 10500 -0.1 31.8 230 12 6 6.0 3.3 | 1.0 33.8 225 17 9 6.5 3.6 10250 0.3 32.5 225 12 6 7.0 3.9 | 1.5 34.7 225 16 8 9.3 5.1 10000 0.9 33.6 220 11 6 8.0 4.4 | 2.4 36.3 220 15 8 11.0 6.0 9750 1.5 34.7 215 11 6 7.2 4.0 | 3.1 37.6 220 14 7 8.4 4.6 9500 2.0 35.6 210 11 5 7.0 3.8 | 3.7 38.7 220 13 7 8.5 4.7 9250 2.5 36.5 205 11 5 7.2 3.9 | 4.3 39.7 215 12 6 7.5 4.1 9000 3.6 38.5 195 11 6 6.4 3.5 | 5.4 41.7 215 10 5 9.1 5.0 8750 4.0 39.2 185 11 6 6.3 3.5 | 6.2 43.2 215 9 5 10.1 5.6 8500 4.5 40.1 180 12 6 5.9 3.3 | 6.9 44.4 215 9 4 9.2 5.0 8250 4.9 40.8 175 12 6 4.8 2.7 | 7.5 45.5 210 8 4 8.2 4.5 8000 5.2 41.4 170 13 7 4.8 2.6 | 8.2 46.8 210 7 3 9.7 5.3 7750 5.6 42.1 170 12 6 5.3 2.9 | 9.0 48.2 210 7 3 11.4 6.3 7500 5.9 42.6 165 11 6 4.5 2.5 | 9.8 49.6 210 7 3 9.3 5.1 7250 6.2 43.2 160 11 6 3.1 1.7 | 10.4 50.7 205 6 3 6.9 3.8 7000 6.5 43.7 155 12 6 6.2 3.4 | 11.0 51.8 205 5 3 10.1 5.5 6750 7.1 44.8 155 9 5 8.5 4.7 | 11.9 53.4 205 6 3 12.5 6.9 6500 7.6 45.7 150 8 4 7.3 4.0 | 12.7 54.9 205 6 3 10.5 5.8 6250 8.1 46.6 145 8 4 6.8 3.7 | 13.5 56.3 205 5 2 10.4 5.7 6000 8.7 47.7 145 8 4 8.5 4.6 | 14.2 57.6 200 4 2 8.7 4.8 5750 9.5 49.1 145 6 3 15.9 8.7 | 15.0 59.0 205 5 2 14.4 7.9 5500 11.1 52.0 135 6 3 26.4 14.5 | 17.7 63.9 200 3 2 76.0 41.7 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 05/22/2024 at 1500 MDT | 05/22/2024 at 1800 MDT | CAPE... +0.7 LI... +1.3 | CAPE... +0.4 LI... +0.9 CINH... -0.2 K Index... +14.8 | CINH... -3.8 K Index... +11.9 | 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 -53.8 -64.8 255 47 24 0.8 0.5 | -54.6 -66.3 260 46 24 1.0 0.5 45000 -52.8 -63.0 260 54 28 -2.7 -1.5 | -53.5 -64.3 265 50 26 -3.8 -2.1 40000 -56.3 -69.3 280 59 30 -2.4 -1.3 | -58.6 -73.5 280 56 29 -3.5 -1.9 38000 -55.6 -68.1 285 60 31 3.7 2.1 | -57.3 -71.1 280 57 30 5.8 3.2 36000 -53.4 -64.1 290 62 32 3.7 2.1 | -53.9 -65.0 280 58 30 5.8 3.2 34000 -50.3 -58.5 295 62 32 6.7 3.6 | -49.6 -57.3 280 57 30 7.3 4.0 32000 -46.3 -51.3 285 58 30 6.7 3.7 | -45.3 -49.5 280 55 28 7.3 4.0 30000 -42.2 -44.0 275 56 29 7.0 3.9 | -40.8 -41.4 280 51 26 7.5 4.1 29000 -40.1 -40.2 275 56 29 7.1 3.9 | -38.6 -37.5 280 47 24 7.5 4.1 28000 -38.0 -36.4 270 55 29 7.1 3.9 | -36.4 -33.5 280 44 22 7.5 4.1 27000 -35.9 -32.6 270 55 28 7.7 4.2 | -34.1 -29.4 280 40 21 8.1 4.4 26000 -33.5 -28.3 265 54 28 8.0 4.4 | -31.7 -25.1 275 41 21 8.1 4.5 25000 -31.1 -24.0 265 53 27 8.0 4.4 | -29.2 -20.6 270 41 21 8.1 4.5 24000 -28.8 -19.8 260 52 27 7.8 4.3 | -26.8 -16.2 265 41 21 7.3 4.0 23000 -26.6 -15.9 260 50 26 7.4 4.1 | -24.9 -12.8 265 42 22 6.4 3.5 22000 -23.8 -10.8 255 47 24 7.4 4.1 | -22.5 -8.5 265 42 22 6.4 3.5 21000 -21.6 -6.9 255 44 23 7.0 3.8 | -20.7 -5.3 260 42 21 6.2 3.4 20000 -19.5 -3.1 250 41 21 7.0 3.8 | -18.9 -2.0 260 39 20 6.3 3.4 19500 -18.5 -1.3 245 39 20 7.0 3.8 | -17.9 -0.2 255 38 20 6.3 3.4 19000 -17.4 0.7 245 38 20 7.0 3.9 | -17.0 1.4 255 37 19 6.1 3.4 18500 -16.4 2.5 240 36 19 7.0 3.8 | -16.0 3.2 250 36 19 8.3 4.6 18000 -15.4 4.3 235 35 18 7.1 3.9 | -14.8 5.4 245 34 18 8.1 4.5 17500 -14.4 6.1 235 34 17 7.6 4.2 | -13.5 7.7 240 33 17 8.4 4.6 17000 -13.2 8.2 230 32 17 8.0 4.4 | -12.3 9.9 240 32 16 8.7 4.7 16500 -12.0 10.4 230 31 16 8.1 4.4 | -11.0 12.2 235 30 16 8.7 4.8 16000 -10.8 12.6 225 30 15 8.5 4.6 | -9.7 14.5 235 29 15 9.0 5.0 15500 -9.6 14.7 225 29 15 8.4 4.6 | -8.3 17.1 235 28 15 9.0 4.9 15000 -8.3 17.1 225 28 14 8.8 4.8 | -7.0 19.4 230 27 14 9.1 5.0 14500 -7.0 19.4 225 27 14 8.8 4.8 | -5.6 21.9 230 27 14 9.1 5.0 14000 -5.7 21.7 225 27 14 8.9 4.9 | -4.3 24.3 230 26 13 9.3 5.1 13500 -4.3 24.3 225 26 13 9.0 4.9 | -2.9 26.8 230 25 13 9.4 5.2 13000 -3.0 26.6 225 25 13 9.0 4.9 | -1.4 29.5 235 24 13 9.3 5.1 12500 -1.7 28.9 230 24 12 9.0 4.9 | -0.1 31.8 235 24 12 9.2 5.0 12000 -0.3 31.5 230 23 12 9.1 5.0 | 1.3 34.3 235 23 12 9.2 5.1 11500 1.0 33.8 235 22 11 9.1 5.0 | 2.7 36.9 235 22 12 9.3 5.1 11000 2.4 36.3 235 21 11 8.6 4.7 | 4.1 39.4 235 22 11 8.8 4.8 10500 3.6 38.5 240 20 10 7.3 4.0 | 5.3 41.5 240 21 11 7.1 3.9 10250 4.2 39.6 240 19 10 10.2 5.6 | 5.9 42.6 240 20 10 10.4 5.7 10000 5.1 41.2 240 19 10 11.4 6.2 | 6.8 44.2 240 20 10 11.7 6.4 9750 5.8 42.4 245 19 10 8.9 4.9 | 7.5 45.5 240 19 10 8.8 4.8 9500 6.5 43.7 245 18 9 9.0 4.9 | 8.1 46.6 245 19 10 8.6 4.7 9250 7.1 44.8 250 17 9 9.5 5.2 | 8.8 47.8 245 19 10 9.3 5.1 9000 7.9 46.2 245 17 9 9.9 5.4 | 9.5 49.1 245 18 9 10.1 5.6 8750 8.6 47.5 250 17 9 9.5 5.2 | 10.3 50.5 245 18 9 9.8 5.4 8500 10.0 50.0 250 16 8 9.4 5.2 | 11.0 51.8 245 17 9 9.6 5.3 8250 10.7 51.3 255 16 8 9.3 5.1 | 12.4 54.3 245 17 9 8.9 4.9 8000 11.4 52.5 255 16 8 9.8 5.4 | 13.1 55.6 250 17 9 9.3 5.1 7750 12.2 54.0 255 15 8 10.3 5.7 | 13.8 56.8 250 16 8 10.1 5.5 7500 12.9 55.2 255 15 8 9.4 5.2 | 14.5 58.1 250 16 8 9.4 5.2 7250 13.6 56.5 260 15 8 8.2 4.5 | 15.2 59.4 250 16 8 8.3 4.6 7000 14.2 57.6 265 15 8 9.9 5.4 | 15.8 60.4 250 16 8 9.6 5.3 6750 15.1 59.2 260 14 7 11.2 6.2 | 16.6 61.9 250 15 8 10.9 6.0 6500 15.9 60.6 260 14 7 10.8 5.9 | 17.4 63.3 250 14 7 10.3 5.7 6250 16.7 62.1 265 14 7 11.6 6.4 | 18.2 64.8 250 14 7 10.7 5.9 6000 17.5 63.5 270 14 7 8.2 4.5 | 19.0 66.2 255 14 7 8.6 4.7 5750 18.1 64.6 265 13 6 11.8 6.5 | 19.6 67.3 255 13 7 10.3 5.7 5500 20.8 69.4 270 12 6 80.0 43.9 | 21.4 70.5 255 11 6 50.8 27.9 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