Soaring Guidance
Issued by NWS Denver/Boulder, CO
Issued by NWS Denver/Boulder, CO
947 UXUS97 KBOU 080023 SRGBOU Soaring Forecast National Weather Service Denver/Boulder, Colorado 1822 MDT Sunday, July 7, 2024 This forecast is for Monday, July 8, 2024: If the trigger temperature of 68.7 F/20.4 C is reached...then Thermal Soaring Index....................... Excellent Maximum rate of lift........................ 1056 ft/min (5.4 m/s) Maximum height of thermals.................. 17533 ft MSL (12240 ft AGL) Forecast maximum temperature................... 82.0 F/28.2 C Time of trigger temperature.................... 0945 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................. 13934 ft MSL (8641 ft AGL) Thermal soaring outlook for Tuesday 07/09...... Excellent Wave Soaring Index............................. Poor Wave Soaring Index trend (to 1800 MDT)......... No change Height of stable layer (12-18K ft MSL)......... None Weak PVA/NVA (through 1800 MDT)................ Weak NVA Potential height of wave....................... 46307 ft MSL (41014 ft AGL) Wave soaring outlook for Tuesday 07/09......... Poor Remarks... Sunrise/Sunset.................... 05:39:41 / 20:29:44 MDT Total possible sunshine........... 14 hr 50 min 3 sec (890 min 3 sec) Altitude of sun at 13:04:43 MDT... 72.55 degrees Upper air data from numerical model forecast valid on 07/08/2024 at 0600 MDT Freezing level.................. 13242 ft MSL (7949 ft AGL) Convective condensation level... 12618 ft MSL (7325 ft AGL) Lifted condensation level....... 14458 ft MSL (9165 ft AGL) Lifted index.................... -5.2 K index......................... +22.2 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 -55.2 -67.4 325 21 11 2.4 1.3 M M M M M 45000 -52.0 -61.6 325 29 15 1.2 0.6 M M M M M 40000 -50.2 -58.4 340 32 17 2.3 1.3 M M M M M 38000 -48.6 -55.5 340 30 15 2.5 1.4 M M M M M 36000 -47.1 -52.8 335 28 14 2.5 1.4 M M M M M 34000 -44.6 -48.3 330 26 14 5.2 2.9 M M M M M 32000 -41.5 -42.7 325 25 13 5.2 2.9 M M M M M 30000 -37.5 -35.5 320 25 13 7.7 4.2 38.6 101.5 8.2 M M 29000 -35.2 -31.4 320 25 13 7.7 4.2 37.8 100.1 7.7 M M 28000 -32.3 -26.1 320 25 13 7.8 4.3 37.0 98.6 7.2 M M 27000 -29.9 -21.8 320 24 13 7.9 4.3 36.2 97.2 6.6 M M 26000 -27.6 -17.7 320 24 12 7.9 4.3 35.5 95.9 6.1 M M 25000 -25.2 -13.4 320 24 12 8.0 4.4 34.9 94.8 5.7 M M 24000 -23.0 -9.4 320 23 12 7.1 3.9 34.0 93.2 5.0 M M 23000 -20.9 -5.6 325 21 11 7.2 3.9 33.0 91.4 4.3 M M 22000 -18.7 -1.7 325 20 10 7.2 3.9 32.1 89.9 3.6 M M 21000 -16.6 2.1 325 20 10 7.1 3.9 31.2 88.1 2.8 M M 20000 -14.5 5.9 325 20 10 7.2 3.9 30.2 86.4 2.0 M M 19500 -13.5 7.7 325 20 10 7.2 4.0 29.8 85.7 1.6 M M 19000 -12.4 9.7 325 20 10 7.2 3.9 29.4 85.0 1.2 M M 18500 -11.4 11.5 325 20 10 7.2 3.9 29.0 84.1 0.8 M M 18000 -10.3 13.5 330 19 10 7.2 3.9 28.5 83.4 0.4 M M 17500 -9.3 15.3 330 19 10 7.6 4.2 28.1 82.6 0.0 M M 17000 -8.2 17.2 330 18 9 7.6 4.2 27.8 82.0 -0.3 1012 5.1 16500 -7.1 19.2 325 18 9 7.5 4.1 27.4 81.3 -0.7 964 4.9 16000 -6.0 21.2 325 17 9 7.4 4.1 27.0 80.6 -1.1 917 4.7 15500 -4.9 23.2 330 16 8 7.3 4.0 26.6 79.9 -1.5 870 4.4 15000 -3.9 25.0 330 15 8 7.1 3.9 26.2 79.1 -1.9 824 4.2 14500 -2.3 27.9 330 13 7 6.8 3.7 25.5 78.0 -2.5 755 3.8 14000 -1.3 29.7 335 12 6 6.8 3.7 25.0 77.0 -3.0 711 3.6 13500 -0.4 31.3 335 10 5 7.3 4.0 24.5 76.2 -3.5 667 3.4 13000 0.8 33.4 335 9 4 7.9 4.3 24.2 75.6 -3.9 619 3.1 12500 1.9 35.4 340 7 4 7.8 4.3 23.9 75.1 -4.3 570 2.9 12000 3.0 37.4 335 5 3 7.3 4.0 23.6 74.4 -4.7 523 2.7 11500 4.0 39.2 330 3 2 7.2 3.9 23.2 73.7 -5.1 477 2.4 11000 5.0 41.0 335 2 1 6.6 3.6 22.7 72.9 -5.6 433 2.2 10500 6.0 42.8 360 1 1 4.9 2.7 22.3 72.1 -6.1 389 2.0 10250 6.2 43.2 015 1 0 4.3 2.4 21.8 71.2 -6.6 374 1.9 10000 6.7 44.1 040 1 0 8.9 4.9 21.5 70.8 -6.9 353 1.8 9750 7.4 45.3 070 1 1 10.9 6.0 21.6 70.8 -6.9 324 1.6 9500 8.1 46.6 090 1 1 8.7 4.8 21.6 70.9 -6.9 295 1.5 9250 8.6 47.5 105 2 1 6.2 3.4 21.4 70.5 -7.2 272 1.4 9000 9.1 48.4 110 2 1 7.8 4.3 21.2 70.1 -7.4 251 1.3 8750 9.8 49.6 120 2 1 9.3 5.1 21.1 70.0 -7.5 224 1.1 8500 10.4 50.7 125 2 1 8.4 4.6 21.0 69.9 -7.6 197 1.0 8250 11.0 51.8 125 2 1 7.9 4.3 20.9 69.6 -7.8 172 0.9 8000 11.6 52.9 125 2 1 8.3 4.6 20.8 69.4 -8.0 147 0.7 7750 12.2 54.0 120 1 1 8.5 4.7 20.7 69.2 -8.1 121 0.6 7500 12.8 55.0 125 1 1 7.6 4.2 20.6 69.0 -8.3 96 0.5 7250 13.3 55.9 150 1 0 6.9 3.8 20.4 68.6 -8.5 73 0.4 7000 13.8 56.8 190 1 0 7.5 4.1 20.2 68.3 -8.7 50 0.3 6750 14.4 57.9 220 1 1 7.5 4.1 20.0 68.0 -8.9 27 0.1 6500 14.9 58.8 240 2 1 6.5 3.6 19.8 67.6 -9.2 5 0.0 6250 15.3 59.5 250 2 1 7.4 4.1 19.6 67.2 -9.5 M M 6000 15.8 60.4 255 2 1 3.7 2.0 19.3 66.8 -9.7 M M 5750 15.7 60.3 260 2 1 -4.1 -2.3 18.6 65.4 -10.6 M M 5500 15.2 59.4 245 2 1 -5.9 -3.2 17.4 63.3 -11.8 M M * * * * * * Numerical weather prediction model forecast data valid * * * * * * 07/08/2024 at 0900 MDT | 07/08/2024 at 1200 MDT | CAPE... +276.0 LI... -1.5 | CAPE... +155.5 LI... -0.6 CINH... -22.8 K Index... +19.8 | CINH... -7.8 K Index... +20.2 | 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 -55.8 -68.4 320 21 11 1.8 1.0 | -56.6 -69.9 325 19 10 2.0 1.1 45000 -53.4 -64.1 340 29 15 1.2 0.6 | -54.0 -65.2 345 27 14 0.5 0.3 40000 -51.3 -60.3 355 41 21 4.6 2.5 | -52.9 -63.2 350 36 18 5.6 3.1 38000 -48.6 -55.5 360 46 23 4.6 2.5 | -49.9 -57.8 355 40 21 5.0 2.7 36000 -45.8 -50.4 005 50 26 4.6 2.5 | -46.9 -52.4 360 45 23 5.0 2.8 34000 -42.8 -45.0 005 48 25 5.3 2.9 | -42.9 -45.2 005 48 24 7.2 4.0 32000 -39.6 -39.3 005 42 22 5.3 2.9 | -38.6 -37.5 005 49 25 7.2 4.0 30000 -36.0 -32.8 005 36 18 6.6 3.6 | -34.1 -29.4 005 48 25 7.6 4.2 29000 -33.5 -28.3 360 31 16 6.6 3.6 | -31.3 -24.3 010 45 23 7.6 4.2 28000 -31.5 -24.7 360 27 14 6.7 3.7 | -29.0 -20.2 010 44 23 7.1 3.9 27000 -29.4 -20.9 360 26 13 7.4 4.0 | -27.1 -16.8 010 38 20 6.2 3.4 26000 -27.2 -17.0 355 24 12 7.4 4.0 | -25.3 -13.5 010 33 17 6.2 3.4 25000 -24.9 -12.8 355 23 12 7.3 4.0 | -23.4 -10.1 005 27 14 6.1 3.4 24000 -22.7 -8.9 355 22 11 7.7 4.2 | -21.4 -6.5 005 24 12 6.9 3.8 23000 -20.4 -4.7 355 21 11 7.7 4.2 | -19.3 -2.7 360 21 11 6.9 3.8 22000 -18.1 -0.6 355 20 10 7.7 4.2 | -17.2 1.0 360 18 9 6.9 3.8 21000 -15.9 3.4 350 18 9 7.1 3.9 | -15.0 5.0 355 16 8 7.7 4.2 20000 -13.8 7.2 345 17 9 7.2 3.9 | -12.7 9.1 350 14 7 7.7 4.2 19500 -12.8 9.0 345 16 8 7.2 3.9 | -11.5 11.3 350 13 7 7.8 4.3 19000 -11.7 10.9 340 16 8 7.1 3.9 | -10.4 13.3 345 12 6 6.5 3.6 18500 -10.7 12.7 335 16 8 7.2 3.9 | -9.5 14.9 340 12 6 6.3 3.5 18000 -9.7 14.5 335 16 8 7.2 4.0 | -8.6 16.5 335 12 6 6.3 3.5 17500 -8.7 16.3 330 16 8 7.0 3.8 | -7.7 18.1 330 12 6 6.4 3.5 17000 -7.7 18.1 330 16 8 7.1 3.9 | -6.7 19.9 325 12 6 6.5 3.6 16500 -6.7 19.9 330 16 8 6.8 3.7 | -5.8 21.6 320 12 6 7.0 3.8 16000 -5.7 21.7 330 15 8 6.8 3.7 | -4.8 23.4 315 12 6 7.1 3.9 15500 -4.7 23.5 330 14 7 6.6 3.6 | -3.8 25.2 310 12 6 6.8 3.7 15000 -3.8 25.2 330 13 7 6.3 3.5 | -2.9 26.8 310 12 6 6.4 3.5 14500 -2.3 27.9 325 11 6 6.5 3.6 | -1.5 29.3 310 11 6 6.4 3.5 14000 -1.4 29.5 325 10 5 6.6 3.6 | -0.6 30.9 305 10 5 6.4 3.5 13500 -0.4 31.3 320 8 4 7.3 4.0 | 0.3 32.5 305 9 4 6.6 3.6 13000 0.7 33.3 325 7 4 7.9 4.3 | 1.3 34.3 300 7 4 6.7 3.7 12500 1.8 35.2 325 6 3 7.8 4.3 | 2.3 36.1 295 5 3 7.4 4.0 12000 2.8 37.0 325 5 3 7.5 4.1 | 3.4 38.1 290 3 1 8.1 4.4 11500 3.9 39.0 325 4 2 7.3 4.0 | 4.6 40.3 250 1 0 7.7 4.2 11000 4.9 40.8 335 2 1 6.6 3.6 | 5.5 41.9 155 1 1 6.9 3.8 10500 5.8 42.4 015 2 1 4.5 2.5 | 6.5 43.7 140 2 1 4.2 2.3 10250 6.1 43.0 030 2 1 3.7 2.0 | 6.7 44.1 140 2 1 4.6 2.5 10000 6.5 43.7 050 2 1 8.8 4.8 | 7.3 45.1 140 3 1 11.0 6.1 9750 7.2 45.0 075 2 1 11.1 6.1 | 8.1 46.6 140 3 1 12.5 6.8 9500 7.9 46.2 090 3 1 8.3 4.5 | 8.9 48.0 140 3 1 9.6 5.3 9250 8.4 47.1 095 3 1 4.8 2.6 | 9.4 48.9 140 3 1 6.5 3.6 9000 8.8 47.8 105 3 2 8.7 4.8 | 10.0 50.0 140 3 1 10.4 5.7 8750 9.6 49.3 115 3 2 11.9 6.5 | 11.0 51.8 140 2 1 12.9 7.1 8500 10.4 50.7 120 3 2 8.3 4.5 | 11.8 53.2 140 2 1 10.2 5.6 8250 10.9 51.6 125 3 2 6.1 3.4 | 12.5 54.5 140 2 1 8.8 4.8 8000 11.3 52.3 125 4 2 7.6 4.2 | 13.2 55.8 140 2 1 10.1 5.6 7750 11.9 53.4 125 4 2 9.0 4.9 | 14.0 57.2 145 2 1 11.0 6.0 7500 12.6 54.7 125 4 2 8.6 4.7 | 14.8 58.6 145 2 1 10.2 5.6 7250 13.2 55.8 120 3 2 8.3 4.6 | 15.5 59.9 145 2 1 9.4 5.2 7000 13.8 56.8 115 3 1 8.1 4.4 | 16.3 61.3 145 2 1 10.9 6.0 6750 14.3 57.7 100 2 1 9.3 5.1 | 17.1 62.8 145 2 1 11.3 6.2 6500 15.1 59.2 090 2 1 10.6 5.8 | 17.9 64.2 145 2 1 10.1 5.6 6250 15.9 60.6 080 1 1 10.4 5.7 | 18.7 65.7 150 2 1 10.5 5.8 6000 16.6 61.9 070 1 1 9.9 5.4 | 19.5 67.1 150 2 1 10.2 5.6 5750 17.4 63.3 060 1 1 14.0 7.7 | 20.4 68.7 150 2 1 18.0 9.9 5500 18.8 65.8 060 1 1 22.4 12.3 | 22.3 72.1 150 2 1 31.0 17.0 07/08/2024 at 1500 MDT | 07/08/2024 at 1800 MDT | CAPE... +79.5 LI... -0.7 | CAPE... +86.8 LI... -0.7 CINH... -13.3 K Index... +24.3 | CINH... -28.2 K Index... +27.1 | 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 -57.3 -71.1 325 21 11 2.0 1.1 | -56.7 -70.1 340 19 10 1.8 1.0 45000 -54.7 -66.5 340 23 12 0.9 0.5 | -54.1 -65.4 340 26 13 1.3 0.7 40000 -52.9 -63.2 345 29 15 4.9 2.7 | -51.9 -61.4 350 33 17 4.2 2.3 38000 -50.2 -58.4 345 31 16 4.6 2.5 | -49.5 -57.1 345 30 16 4.0 2.2 36000 -47.5 -53.5 350 33 17 4.7 2.6 | -47.1 -52.8 345 28 14 4.1 2.2 34000 -43.4 -46.1 350 34 17 7.7 4.2 | -43.3 -45.9 345 27 14 7.3 4.0 32000 -38.7 -37.7 350 34 18 7.7 4.2 | -38.3 -36.9 345 26 13 7.2 4.0 30000 -33.4 -28.1 355 34 17 8.0 4.4 | -33.7 -28.7 345 26 13 7.9 4.3 29000 -31.0 -23.8 360 34 17 8.0 4.4 | -31.3 -24.3 350 26 13 7.9 4.3 28000 -28.6 -19.5 360 34 17 7.9 4.3 | -29.0 -20.2 350 26 13 8.0 4.4 27000 -26.3 -15.3 360 33 17 7.8 4.3 | -26.5 -15.7 350 26 13 8.0 4.4 26000 -23.9 -11.0 360 33 17 7.8 4.3 | -24.1 -11.4 350 26 14 8.0 4.4 25000 -21.6 -6.9 360 33 17 7.9 4.3 | -21.7 -7.1 350 27 14 8.1 4.4 24000 -19.6 -3.3 360 30 16 6.2 3.4 | -19.4 -2.9 350 26 14 7.8 4.3 23000 -17.8 -0.0 360 28 14 6.2 3.4 | -17.1 1.2 350 26 13 7.8 4.3 22000 -16.0 3.2 355 25 13 6.3 3.4 | -14.7 5.5 350 26 13 7.6 4.2 21000 -14.0 6.8 350 22 11 6.6 3.6 | -12.9 8.8 350 24 12 5.7 3.1 20000 -12.0 10.4 345 19 10 6.6 3.6 | -11.2 11.8 340 23 12 5.7 3.1 19500 -11.0 12.2 340 18 9 6.6 3.6 | -10.4 13.3 340 22 11 5.7 3.1 19000 -10.0 14.0 335 17 9 6.6 3.6 | -9.5 14.9 335 22 11 6.2 3.4 18500 -9.0 15.8 330 16 8 6.6 3.6 | -8.6 16.5 330 21 11 6.5 3.6 18000 -8.0 17.6 325 15 8 6.6 3.6 | -7.8 18.0 325 21 11 7.1 3.9 17500 -7.1 19.2 325 15 8 6.6 3.6 | -6.7 19.9 325 21 11 8.2 4.5 17000 -6.1 21.0 320 15 8 6.6 3.6 | -5.6 21.9 320 20 10 8.4 4.6 16500 -5.2 22.6 315 15 8 7.5 4.1 | -4.5 23.9 315 19 10 7.7 4.2 16000 -4.1 24.6 310 15 8 7.9 4.3 | -2.8 27.0 315 17 9 7.7 4.2 15500 -3.1 26.4 305 14 7 8.3 4.5 | -1.7 28.9 310 15 8 7.4 4.1 15000 -1.3 29.7 305 12 6 8.6 4.7 | -0.6 30.9 315 12 6 7.6 4.2 14500 -0.2 31.6 300 10 5 6.2 3.4 | 0.4 32.7 315 9 4 5.4 3.0 14000 0.7 33.3 300 7 4 5.9 3.2 | 1.1 34.0 320 4 2 5.1 2.8 13500 1.6 34.9 295 4 2 6.3 3.4 | 1.8 35.2 005 1 0 6.8 3.7 13000 2.5 36.5 250 1 1 6.6 3.6 | 3.0 37.4 115 1 1 7.8 4.3 12500 3.4 38.1 155 3 1 7.7 4.2 | 4.1 39.4 135 2 1 8.5 4.7 12000 4.7 40.5 155 3 2 8.9 4.9 | 5.5 41.9 135 2 1 9.3 5.1 11500 5.9 42.6 150 4 2 9.0 5.0 | 6.9 44.4 135 2 1 9.2 5.1 11000 7.3 45.1 150 4 2 8.9 4.9 | 8.3 46.9 130 2 1 8.9 4.9 10500 8.6 47.5 150 4 2 4.8 2.6 | 9.6 49.3 130 2 1 4.8 2.6 10250 8.8 47.8 150 4 2 5.9 3.2 | 9.8 49.6 130 2 1 6.2 3.4 10000 9.7 49.5 150 3 2 13.1 7.2 | 10.7 51.3 130 2 1 13.4 7.4 9750 10.6 51.1 150 3 2 13.3 7.3 | 11.6 52.9 135 2 1 12.9 7.1 9500 11.5 52.7 150 3 2 10.0 5.5 | 12.6 54.7 135 2 1 10.3 5.7 9250 12.0 53.6 150 3 2 6.5 3.5 | 13.2 55.8 135 2 1 7.2 4.0 9000 12.7 54.9 150 3 2 10.2 5.6 | 13.8 56.8 135 2 1 10.2 5.6 8750 13.5 56.3 150 3 2 12.0 6.6 | 14.7 58.5 135 2 1 11.8 6.5 8500 14.4 57.9 150 3 2 10.5 5.7 | 15.5 59.9 135 2 1 10.4 5.7 8250 15.1 59.2 150 3 2 9.7 5.3 | 16.2 61.2 140 2 1 9.7 5.3 8000 15.8 60.4 150 3 2 10.2 5.6 | 17.0 62.6 140 2 1 9.8 5.4 7750 16.6 61.9 150 3 2 10.5 5.8 | 17.7 63.9 140 2 1 9.7 5.3 7500 17.4 63.3 150 3 2 10.4 5.7 | 18.4 65.1 140 2 1 10.0 5.5 7250 18.2 64.8 150 3 1 10.5 5.8 | 19.2 66.6 145 2 1 10.0 5.5 7000 18.9 66.0 155 3 1 9.7 5.3 | 19.9 67.8 145 2 1 10.3 5.6 6750 19.6 67.3 155 3 1 9.7 5.3 | 20.7 69.3 145 1 1 10.6 5.8 6500 20.4 68.7 155 3 1 10.9 6.0 | 21.5 70.7 150 1 1 10.3 5.6 6250 21.2 70.2 155 3 1 11.0 6.0 | 22.2 72.0 150 1 1 9.8 5.4 6000 22.1 71.8 155 2 1 10.8 5.9 | 23.0 73.4 155 1 1 10.9 6.0 5750 23.0 73.4 160 2 1 18.2 10.0 | 24.0 75.2 155 1 1 15.6 8.5 5500 24.9 76.8 155 2 1 30.7 16.9 | 25.3 77.5 155 1 1 19.8 10.9 ________________________________________________________________________________ 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 near the old Stapleton Airport site in Denver, Colorado at North Latitude: 39 deg 46 min 5.016 sec West Longitude: 104 deg 52 min 9.984 sec Elevation: 5285 feet (1611 meters) and may not be representative of other areas along the Front Range of the Colorado Rocky Mountains. 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