Soaring Guidance
Issued by NWS Denver/Boulder, CO
Issued by NWS Denver/Boulder, CO
124 UXUS97 KBOU 100131 SRGBOU Soaring Forecast National Weather Service Denver/Boulder, Colorado 1829 MST Thursday, January 9, 2025 This forecast is for Friday, January 10, 2025: If the trigger temperature of 33.3 F/0.7 C is reached...then Thermal Soaring Index....................... Good Maximum rate of lift........................ 654 ft/min (3.3 m/s) Maximum height of thermals.................. 13195 ft MSL (7894 ft AGL) Forecast maximum temperature................... 39.0 F/4.3 C Time of trigger temperature.................... 1130 MST 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................. 9634 ft MSL (4333 ft AGL) Thermal soaring outlook for Saturday 01/11..... Fair Wave Soaring Index............................. Fair Wave Soaring Index trend (to 1700 MST)......... No change Height of stable layer (12-18K ft MSL)......... 17863 ft MSL (12562 ft AGL) Weak PVA/NVA (through 1700 MST)................ Weak NVA Potential height of wave....................... 29932 ft MSL (24631 ft AGL) Wave soaring outlook for Saturday 01/11........ Fair Remarks... Sunrise/Sunset.................... 07:20:10 / 16:54:15 MST Total possible sunshine........... 9 hr 34 min 5 sec (574 min 5 sec) Altitude of sun at 12:07:13 MST... 28.38 degrees Upper air data from numerical model forecast valid on 01/10/2025 at 0500 MST Freezing level.................. Entire airmass below 32 F / 0 C Convective condensation level... 24036 ft MSL (18735 ft AGL) Lifted condensation level....... 15986 ft MSL (10684 ft AGL) Lifted index.................... +17.7 K index......................... -31.3 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 -54.5 -66.1 345 38 20 2.3 1.2 M M M M M 45000 -51.1 -60.0 005 48 25 2.0 1.1 M M M M M 40000 -49.4 -56.9 005 63 33 1.1 0.6 M M M M M 38000 -49.2 -56.6 005 70 36 -0.9 -0.5 M M M M M 36000 -49.8 -57.6 015 80 41 -1.0 -0.5 M M M M M 34000 -50.3 -58.5 020 91 47 -1.6 -0.9 M M M M M 32000 -48.0 -54.4 025 107 55 4.0 2.2 M M M M M 30000 -45.6 -50.1 025 121 62 6.0 3.3 32.2 90.0 21.1 M M 29000 -43.3 -45.9 025 117 60 7.5 4.1 31.2 88.1 20.6 M M 28000 -41.0 -41.8 025 113 58 7.5 4.1 30.3 86.5 20.2 M M 27000 -38.8 -37.8 020 109 56 7.5 4.1 29.5 85.1 19.8 M M 26000 -36.4 -33.5 020 105 54 8.2 4.5 28.8 83.9 19.5 M M 25000 -33.9 -29.0 020 102 53 8.3 4.5 28.2 82.7 19.3 M M 24000 -31.4 -24.5 020 100 51 8.2 4.5 27.7 81.8 19.1 M M 23000 -29.1 -20.4 015 97 50 7.4 4.1 27.0 80.7 18.8 M M 22000 -26.8 -16.2 015 95 49 7.4 4.1 26.1 79.0 18.3 M M 21000 -24.6 -12.3 015 93 48 7.6 4.2 25.4 77.6 17.9 M M 20000 -23.5 -10.3 015 87 45 1.4 0.8 23.2 73.8 16.3 M M 19500 -23.3 -9.9 015 84 43 1.3 0.7 21.7 71.0 15.1 M M 19000 -23.1 -9.6 010 80 41 1.3 0.7 20.2 68.3 13.9 M M 18500 -22.9 -9.2 010 76 39 1.1 0.6 18.7 65.7 12.7 M M 18000 -22.7 -8.9 010 72 37 -2.6 -1.4 17.3 63.1 11.5 M M 17500 -23.6 -10.5 005 66 34 -5.6 -3.1 14.5 58.2 9.2 M M 17000 -24.8 -12.6 005 58 30 -1.8 -1.0 10.7 51.2 5.9 M M 16500 -24.8 -12.6 360 53 27 -0.1 -0.1 9.0 48.1 4.4 M M 16000 -24.9 -12.8 360 48 25 1.8 1.0 7.3 45.2 3.0 M M 15500 -24.2 -11.6 355 45 23 4.8 2.6 6.4 43.5 2.2 M M 15000 -23.5 -10.3 355 43 22 5.2 2.9 5.6 42.0 1.5 M M 14500 -22.5 -8.5 355 40 21 7.1 3.9 5.0 41.0 1.0 M M 14000 -21.5 -6.7 350 38 20 7.0 3.8 4.5 40.2 0.6 M M 13500 -20.4 -4.7 350 36 19 7.4 4.1 4.1 39.4 0.2 M M 13000 -19.3 -2.7 350 34 18 7.4 4.0 3.7 38.7 -0.2 629 3.2 12500 -18.2 -0.8 350 33 17 7.5 4.1 3.3 38.0 -0.5 581 3.0 12000 -17.0 1.4 350 31 16 7.4 4.1 3.0 37.4 -0.9 533 2.7 11500 -16.0 3.2 350 29 15 7.2 3.9 2.6 36.6 -1.3 485 2.5 11000 -14.9 5.2 350 26 13 7.2 4.0 2.2 35.9 -1.6 438 2.2 10500 -13.8 7.2 345 23 12 7.1 3.9 1.8 35.2 -2.0 390 2.0 10250 -13.2 8.2 345 21 11 8.5 4.6 1.6 34.9 -2.2 366 1.9 10000 -12.7 9.1 345 20 10 3.5 1.9 1.4 34.6 -2.4 342 1.7 9750 -12.5 9.5 345 19 10 5.0 2.8 0.8 33.4 -3.0 331 1.7 9500 -11.8 10.8 345 18 9 11.2 6.2 0.8 33.4 -3.0 301 1.5 9250 -11.1 12.0 340 16 8 9.1 5.0 0.8 33.5 -3.0 272 1.4 9000 -10.5 13.1 340 15 8 6.0 3.3 0.7 33.2 -3.1 247 1.3 8750 -10.1 13.8 340 14 7 6.3 3.4 0.3 32.6 -3.5 228 1.2 8500 -9.4 15.1 335 13 7 10.2 5.6 0.2 32.4 -3.6 201 1.0 8250 -8.7 16.3 330 12 6 7.4 4.1 0.2 32.4 -3.6 173 0.9 8000 -8.4 16.9 325 10 5 4.1 2.2 -0.1 31.7 -4.0 154 0.8 7750 -8.0 17.6 320 9 4 6.0 3.3 -0.5 31.0 -4.4 136 0.7 7500 -7.5 18.5 305 7 4 7.5 4.1 -0.7 30.7 -4.6 113 0.6 7250 -7.0 19.4 295 7 3 6.1 3.3 -1.0 30.3 -4.9 90 0.5 7000 -6.6 20.1 280 7 4 5.1 2.8 -1.3 29.7 -5.2 71 0.4 6750 -6.2 20.8 270 7 4 6.2 3.4 -1.6 29.1 -5.5 51 0.3 6500 -5.8 21.6 260 8 4 1.3 0.7 -2.0 28.4 -5.9 33 0.2 6250 -6.0 21.2 260 10 5 -3.9 -2.2 -2.9 26.8 -6.9 32 0.2 6000 -6.2 20.8 260 11 6 -0.6 -0.3 -3.8 25.1 -7.8 30 0.2 5750 -6.4 20.5 260 12 6 -8.8 -4.8 -4.8 23.4 -8.8 29 0.1 5500 -7.8 18.0 245 8 4 -26.9 -14.8 -6.9 19.6 -11.0 64 0.3 * * * * * * Numerical weather prediction model forecast data valid * * * * * * 01/10/2025 at 0800 MST | 01/10/2025 at 1100 MST | CAPE... 0.0 LI... +15.7 | CAPE... 0.0 LI... +14.3 CINH... -0.2 K Index... -32.6 | CINH... -0.1 K Index... -22.6 | 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 -56.1 -69.0 345 39 20 2.5 1.4 | -57.2 -71.0 335 30 15 2.3 1.3 45000 -52.4 -62.3 350 51 26 1.9 1.0 | -53.7 -64.7 345 37 19 1.3 0.7 40000 -51.4 -60.5 010 70 36 0.7 0.4 | -55.2 -67.4 005 70 36 -1.0 -0.5 38000 -51.2 -60.2 015 79 41 -0.4 -0.2 | -54.8 -66.6 005 83 43 2.4 1.3 36000 -51.4 -60.5 015 89 46 -0.4 -0.2 | -53.3 -63.9 005 96 49 2.4 1.3 34000 -51.4 -60.5 015 99 51 5.0 2.7 | -51.6 -60.9 010 107 55 7.0 3.8 32000 -47.9 -54.2 020 105 54 5.9 3.2 | -47.4 -53.3 010 101 52 7.0 3.9 30000 -44.3 -47.7 025 111 57 7.5 4.1 | -43.2 -45.8 015 96 49 7.8 4.3 29000 -42.0 -43.6 025 107 55 7.6 4.2 | -40.9 -41.6 015 92 47 7.7 4.2 28000 -39.7 -39.5 025 103 53 7.6 4.2 | -38.0 -36.4 015 88 45 7.7 4.2 27000 -37.4 -35.3 025 99 51 7.6 4.2 | -35.7 -32.3 020 84 43 7.7 4.2 26000 -35.1 -31.2 020 95 49 7.5 4.1 | -33.4 -28.1 020 81 42 7.5 4.1 25000 -32.9 -27.2 020 92 47 7.5 4.1 | -31.2 -24.2 020 78 40 7.5 4.1 24000 -30.6 -23.1 015 89 46 7.6 4.1 | -28.9 -20.0 020 75 38 7.6 4.2 23000 -28.3 -18.9 015 87 45 7.7 4.2 | -26.8 -16.2 015 73 38 7.2 3.9 22000 -26.0 -14.8 015 86 45 7.8 4.3 | -24.6 -12.3 015 72 37 7.2 3.9 21000 -23.7 -10.7 015 86 44 8.0 4.4 | -22.5 -8.5 010 71 36 6.9 3.8 20000 -21.8 -7.2 015 83 43 5.6 3.0 | -20.7 -5.3 010 69 35 6.0 3.3 19500 -21.0 -5.8 015 82 42 5.6 3.1 | -19.8 -3.6 010 67 35 6.1 3.3 19000 -20.2 -4.4 015 81 42 5.6 3.1 | -18.9 -2.0 010 66 34 6.1 3.3 18500 -19.3 -2.7 015 79 41 5.8 3.2 | -18.0 -0.4 010 65 34 6.1 3.3 18000 -18.6 -1.5 015 77 40 2.3 1.2 | -17.2 1.0 010 64 33 4.6 2.5 17500 -18.4 -1.1 010 74 38 1.6 0.9 | -16.5 2.3 010 62 32 4.8 2.6 17000 -18.2 -0.8 010 69 36 -1.2 -0.6 | -15.8 3.6 010 60 31 3.7 2.1 16500 -18.4 -1.1 005 65 34 -1.3 -0.7 | -15.3 4.5 010 58 30 3.3 1.8 16000 -18.6 -1.5 005 61 32 -0.7 -0.4 | -14.8 5.4 010 56 29 2.7 1.5 15500 -18.6 -1.5 360 58 30 -0.2 -0.1 | -14.6 5.7 005 54 28 0.9 0.5 15000 -18.6 -1.5 360 54 28 0.3 0.2 | -14.4 6.1 005 52 27 1.0 0.6 14500 -18.4 -1.1 355 50 26 1.6 0.9 | -14.2 6.4 360 49 25 0.9 0.5 14000 -18.2 -0.8 355 46 24 1.8 1.0 | -14.1 6.6 355 47 24 1.3 0.7 13500 -17.7 0.1 350 42 22 3.6 2.0 | -13.8 7.2 355 44 23 2.0 1.1 13000 -17.2 1.0 350 39 20 3.8 2.1 | -13.5 7.7 350 41 21 2.5 1.4 12500 -16.4 2.5 345 36 18 6.5 3.6 | -12.9 8.8 350 38 20 3.9 2.1 12000 -15.4 4.3 345 33 17 6.5 3.6 | -12.4 9.7 345 35 18 4.5 2.4 11500 -14.4 6.1 345 31 16 7.4 4.1 | -11.5 11.3 345 32 17 6.2 3.4 11000 -13.3 8.1 345 30 15 7.4 4.0 | -10.6 12.9 345 30 15 6.5 3.6 10500 -12.2 10.0 345 28 14 7.1 3.9 | -9.5 14.9 345 28 14 7.2 3.9 10250 -11.6 11.1 350 27 14 8.6 4.7 | -9.0 15.8 345 26 14 8.0 4.4 10000 -11.1 12.0 350 26 13 3.0 1.7 | -8.5 16.7 345 26 13 3.7 2.0 9750 -11.0 12.2 350 26 13 4.3 2.3 | -8.3 17.1 345 25 13 4.8 2.6 9500 -10.3 13.5 350 24 12 10.9 6.0 | -7.6 18.3 345 24 12 9.9 5.4 9250 -9.6 14.7 350 22 11 8.6 4.7 | -7.0 19.4 345 22 11 7.9 4.3 9000 -9.0 15.8 345 20 10 4.7 2.6 | -6.5 20.3 340 20 10 4.5 2.5 8750 -8.8 16.2 345 19 10 4.7 2.6 | -6.2 20.8 340 19 10 4.8 2.6 8500 -8.2 17.2 345 16 8 8.4 4.6 | -5.7 21.7 335 16 8 7.4 4.1 8250 -7.7 18.1 340 13 7 6.6 3.6 | -5.2 22.6 330 14 7 5.5 3.0 8000 -7.3 18.9 330 11 6 4.3 2.3 | -4.9 23.2 320 12 6 3.3 1.8 7750 -6.9 19.6 325 9 5 6.8 3.7 | -4.6 23.7 310 10 5 5.7 3.1 7500 -6.3 20.7 305 8 4 8.6 4.7 | -4.1 24.6 300 9 5 7.6 4.2 7250 -5.7 21.7 295 8 4 5.6 3.1 | -3.6 25.5 285 9 5 5.9 3.2 7000 -5.4 22.3 285 8 4 3.8 2.1 | -3.2 26.2 280 9 4 4.5 2.5 6750 -5.1 22.8 280 8 4 5.7 3.1 | -2.8 27.0 275 8 4 7.3 4.0 6500 -4.8 23.4 275 9 5 -0.2 -0.1 | -2.3 27.9 270 9 4 4.8 2.6 6250 -5.1 22.8 270 10 5 -6.6 -3.6 | -2.2 28.0 265 8 4 0.8 0.4 6000 -5.5 22.1 260 10 5 -3.0 -1.7 | -2.1 28.2 255 7 4 1.1 0.6 5750 -5.9 21.4 255 11 6 -10.9 -6.0 | -2.0 28.4 250 7 4 4.2 2.3 5500 -7.5 18.5 245 8 4 -29.6 -16.3 | -1.4 29.5 240 6 3 14.2 7.8 01/10/2025 at 1400 MST | 01/10/2025 at 1700 MST | CAPE... 0.0 LI... +11.1 | CAPE... 0.0 LI... +6.5 CINH... 0.0 K Index... -11.3 | CINH... -0.4 K Index... +6.8 | 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 -57.6 -71.7 325 26 14 2.7 1.5 | -57.7 -71.9 305 28 14 2.2 1.2 45000 -53.6 -64.5 350 31 16 1.2 0.7 | -54.4 -65.9 330 27 14 0.6 0.3 40000 -56.0 -68.8 360 60 31 -1.6 -0.9 | -57.1 -70.8 345 52 27 -1.7 -1.0 38000 -55.6 -68.1 360 70 36 3.1 1.7 | -56.1 -69.0 350 61 31 4.3 2.3 36000 -53.7 -64.7 360 80 41 3.1 1.7 | -53.6 -64.5 350 68 35 4.3 2.3 34000 -51.5 -60.7 360 87 45 7.5 4.1 | -50.7 -59.3 350 73 38 7.7 4.2 32000 -47.2 -53.0 360 80 41 7.1 3.9 | -46.2 -51.2 350 66 34 7.5 4.1 30000 -42.9 -45.2 360 74 38 8.5 4.7 | -41.7 -43.1 350 59 30 7.6 4.2 29000 -40.4 -40.7 360 72 37 8.4 4.6 | -39.4 -38.9 350 58 30 7.7 4.2 28000 -37.9 -36.2 360 70 36 8.4 4.6 | -37.1 -34.8 345 57 29 7.7 4.2 27000 -35.4 -31.7 005 68 35 8.4 4.6 | -34.3 -29.7 345 56 29 7.7 4.2 26000 -32.3 -26.1 005 65 33 8.1 4.4 | -32.0 -25.6 345 53 27 7.7 4.2 25000 -29.9 -21.8 005 62 32 8.1 4.4 | -29.7 -21.5 345 50 26 7.8 4.3 24000 -27.5 -17.5 010 58 30 8.0 4.4 | -27.4 -17.3 345 47 24 7.8 4.3 23000 -25.3 -13.5 010 57 29 7.1 3.9 | -25.0 -13.0 345 45 23 8.0 4.4 22000 -23.2 -9.8 005 56 29 7.1 3.9 | -22.6 -8.7 345 43 22 8.0 4.4 21000 -21.1 -6.0 005 55 28 6.9 3.8 | -20.2 -4.4 345 42 21 7.4 4.1 20000 -19.2 -2.6 005 55 28 6.6 3.6 | -18.2 -0.8 345 42 22 6.9 3.8 19500 -18.2 -0.8 005 55 28 6.6 3.6 | -17.2 1.0 345 43 22 6.9 3.8 19000 -17.2 1.0 005 55 28 6.6 3.6 | -16.2 2.8 345 43 22 6.8 3.8 18500 -16.2 2.8 005 54 28 6.5 3.5 | -15.2 4.6 345 44 22 6.5 3.6 18000 -15.4 4.3 005 53 27 4.8 2.7 | -14.4 6.1 345 43 22 4.5 2.5 17500 -14.7 5.5 005 51 26 4.9 2.7 | -13.7 7.3 345 43 22 4.6 2.5 17000 -14.0 6.8 005 50 26 5.4 3.0 | -13.1 8.4 350 43 22 4.7 2.6 16500 -13.1 8.4 005 48 25 5.5 3.0 | -12.4 9.7 350 43 22 4.8 2.6 16000 -12.3 9.9 005 47 24 5.4 3.0 | -11.7 10.9 350 43 22 5.2 2.9 15500 -11.5 11.3 360 47 24 5.2 2.8 | -10.8 12.6 350 43 22 5.9 3.2 15000 -10.7 12.7 360 46 24 5.2 2.9 | -9.9 14.2 350 42 21 5.9 3.2 14500 -10.1 13.8 355 45 23 3.4 1.8 | -9.2 15.4 350 41 21 4.3 2.3 14000 -9.6 14.7 355 45 23 3.6 2.0 | -8.6 16.5 350 40 20 4.3 2.4 13500 -9.1 15.6 350 44 23 2.6 1.4 | -7.9 17.8 350 39 20 5.6 3.1 13000 -8.7 16.3 350 43 22 2.6 1.4 | -7.0 19.4 350 38 19 5.5 3.0 12500 -8.2 17.2 350 41 21 3.3 1.8 | -5.6 21.9 345 36 18 7.3 4.0 12000 -7.4 18.7 345 37 19 3.5 1.9 | -4.5 23.9 345 34 18 6.9 3.8 11500 -6.9 19.6 345 34 17 3.8 2.1 | -3.6 25.5 345 32 17 5.3 2.9 11000 -6.3 20.7 340 30 16 4.1 2.3 | -2.7 27.1 345 30 15 5.0 2.7 10500 -5.6 21.9 335 27 14 5.1 2.8 | -2.1 28.2 340 27 14 3.4 1.9 10250 -5.2 22.6 335 25 13 5.8 3.2 | -1.9 28.6 340 26 13 2.4 1.3 10000 -4.8 23.4 335 23 12 2.9 1.6 | -1.6 29.1 335 24 13 6.7 3.7 9750 -4.6 23.7 335 23 12 4.0 2.2 | -0.9 30.4 335 22 11 8.3 4.5 9500 -4.1 24.6 330 21 11 7.6 4.2 | -0.5 31.1 330 20 10 4.7 2.6 9250 -3.6 25.5 325 19 10 7.1 3.9 | -0.1 31.8 330 19 10 6.5 3.6 9000 -3.1 26.4 325 17 9 3.3 1.8 | 0.4 32.7 325 17 9 2.8 1.6 8750 -3.0 26.6 320 16 8 2.7 1.5 | 0.5 32.9 320 15 8 2.0 1.1 8500 -2.6 27.3 315 14 7 5.9 3.3 | 0.8 33.4 315 14 7 4.8 2.7 8250 -2.2 28.0 305 13 7 4.7 2.6 | 1.1 34.0 305 12 6 4.1 2.2 8000 -1.9 28.6 300 12 6 2.9 1.6 | 1.4 34.5 295 11 6 3.7 2.1 7750 -1.7 28.9 290 12 6 4.8 2.6 | 1.7 35.1 295 11 6 4.1 2.3 7500 -1.2 29.8 285 11 6 7.9 4.3 | 2.0 35.6 290 11 6 5.5 3.0 7250 -0.7 30.7 275 11 5 5.0 2.8 | 2.4 36.3 290 11 6 3.2 1.7 7000 -0.4 31.3 275 11 6 3.1 1.7 | 2.5 36.5 285 12 6 0.4 0.2 6750 -0.2 31.6 275 11 6 3.8 2.1 | 2.5 36.5 280 14 7 -0.4 -0.2 6500 0.1 32.2 265 10 5 3.8 2.1 | 2.5 36.5 275 14 7 -0.9 -0.5 6250 0.3 32.5 260 9 5 4.0 2.2 | 2.4 36.3 270 13 7 -0.7 -0.4 6000 0.6 33.1 255 8 4 3.3 1.8 | 2.4 36.3 265 12 6 1.0 0.5 5750 0.8 33.4 245 7 4 5.9 3.2 | 2.3 36.1 255 10 5 -4.6 -2.5 5500 1.4 34.5 235 5 3 11.6 6.3 | 1.3 34.3 240 7 4 -21.2 -11.6 ________________________________________________________________________________ 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