Soaring Guidance
Issued by NWS Denver/Boulder, CO
Issued by NWS Denver/Boulder, CO
478 UXUS97 KBOU 251323 SRGBOU Soaring Forecast National Weather Service Denver/Boulder, Colorado 0718 MDT Saturday, May 25, 2024 This forecast is for Saturday, May 25, 2024: If the trigger temperature of 70.4 F/21.3 C is reached...then Thermal Soaring Index....................... Good Maximum rate of lift........................ 657 ft/min (3.3 m/s) Maximum height of thermals.................. 16575 ft MSL (11248 ft AGL) Forecast maximum temperature................... 76.0 F/24.9 C Time of trigger temperature.................... 1030 MDT Time of overdevelopment........................ 1500 MDT Middle/high clouds during soaring window....... Broken/overcast opaque middle Surface winds during soaring window............ 20 mph or less Height of the -3 thermal index................. 9304 ft MSL (3976 ft AGL) Thermal soaring outlook for Sunday 05/26....... Good 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 PVA Potential height of wave....................... 39806 ft MSL (34479 ft AGL) Wave soaring outlook for Sunday 05/26.......... Good Remarks... Sunrise/Sunset.................... 05:36:30 / 20:16:32 MDT Total possible sunshine........... 14 hr 40 min 1 sec (880 min 1 sec) Altitude of sun at 12:56:31 MDT... 71.36 degrees Upper air data from numerical model forecast valid on 05/25/2024 at 0600 MDT Freezing level.................. 12795 ft MSL (7468 ft AGL) Convective condensation level... 16696 ft MSL (11369 ft AGL) Lifted condensation level....... 16769 ft MSL (11442 ft AGL) Lifted index.................... -0.0 K index......................... +13.6 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 -55.6 -68.1 255 58 30 0.9 0.5 M M M M M 45000 -54.5 -66.1 250 76 39 -1.3 -0.7 M M M M M 40000 -56.3 -69.3 245 88 45 -1.2 -0.7 M M M M M 38000 -55.1 -67.2 245 84 43 3.7 2.0 M M M M M 36000 -52.9 -63.2 245 76 39 3.7 2.0 M M M M M 34000 -49.4 -56.9 245 67 35 7.7 4.2 M M M M M 32000 -44.8 -48.6 245 61 31 7.7 4.2 M M M M M 30000 -40.1 -40.2 245 56 29 8.0 4.4 35.2 95.3 8.1 M M 29000 -37.7 -35.9 245 56 29 8.0 4.4 34.4 94.0 7.6 M M 28000 -35.3 -31.5 245 55 29 8.0 4.4 33.8 92.9 7.2 M M 27000 -32.9 -27.2 245 55 28 7.9 4.3 33.2 91.8 6.9 M M 26000 -30.5 -22.9 245 54 28 7.9 4.3 32.4 90.4 6.3 M M 25000 -28.2 -18.8 245 54 28 7.9 4.3 31.8 89.2 5.9 M M 24000 -25.8 -14.4 245 53 27 8.0 4.4 31.2 88.2 5.5 M M 23000 -23.4 -10.1 245 51 26 8.0 4.4 30.4 86.8 4.9 M M 22000 -21.0 -5.8 245 49 25 8.0 4.4 29.8 85.7 4.4 M M 21000 -18.6 -1.5 245 47 24 7.1 3.9 29.2 84.6 4.0 M M 20000 -16.5 2.3 245 45 23 7.0 3.9 28.2 82.7 3.1 M M 19500 -15.5 4.1 245 44 23 7.0 3.9 27.7 81.8 2.7 M M 19000 -14.4 6.1 245 43 22 7.0 3.9 27.2 81.0 2.4 M M 18500 -12.9 8.8 245 41 21 6.3 3.5 26.5 79.7 1.7 M M 18000 -12.0 10.4 245 40 21 6.4 3.5 25.9 78.7 1.2 M M 17500 -11.1 12.0 245 39 20 6.9 3.8 25.4 77.7 0.7 M M 17000 -10.0 14.0 245 37 19 7.2 4.0 24.9 76.9 0.3 M M 16500 -8.9 16.0 240 35 18 7.3 4.0 24.5 76.1 -0.1 1041 5.3 16000 -7.8 18.0 245 35 18 8.1 4.4 24.2 75.5 -0.5 993 5.0 15500 -6.6 20.1 245 35 18 8.1 4.4 23.9 75.0 -0.8 942 4.8 15000 -5.4 22.3 245 35 18 8.2 4.5 23.6 74.5 -1.0 892 4.5 14500 -4.2 24.4 250 34 17 8.2 4.5 23.4 74.1 -1.3 841 4.3 14000 -3.0 26.6 250 33 17 8.6 4.7 23.1 73.7 -1.6 790 4.0 13500 -1.7 28.9 250 32 17 8.7 4.8 23.0 73.3 -1.7 737 3.7 13000 -0.5 31.1 255 31 16 8.9 4.9 22.8 73.1 -1.9 683 3.5 12500 0.9 33.6 255 31 16 9.1 5.0 22.7 72.8 -2.1 628 3.2 12000 2.2 36.0 260 30 15 9.1 5.0 22.6 72.7 -2.2 573 2.9 11500 3.6 38.5 260 29 15 9.1 5.0 22.5 72.5 -2.3 518 2.6 11000 4.9 40.8 260 28 14 8.7 4.8 22.4 72.3 -2.4 462 2.3 10500 6.1 43.0 260 27 14 7.3 4.0 22.1 71.8 -2.7 411 2.1 10250 6.7 44.1 260 27 14 9.8 5.4 22.0 71.6 -2.8 387 2.0 10000 7.6 45.7 255 25 13 10.9 6.0 22.1 71.8 -2.7 354 1.8 9750 8.3 46.9 255 25 13 8.6 4.7 22.1 71.7 -2.8 326 1.7 9500 8.9 48.0 255 24 12 8.2 4.5 22.0 71.5 -2.9 300 1.5 9250 9.5 49.1 255 23 12 8.8 4.8 21.9 71.3 -3.0 274 1.4 9000 10.2 50.4 250 23 12 8.6 4.7 21.8 71.2 -3.1 246 1.3 8750 10.8 51.4 250 21 11 7.4 4.0 21.6 71.0 -3.3 221 1.1 8500 11.3 52.3 245 21 11 7.0 3.8 21.4 70.6 -3.5 198 1.0 8250 11.8 53.2 245 20 10 7.3 4.0 21.2 70.2 -3.7 175 0.9 8000 12.3 54.1 240 19 10 5.1 2.8 21.0 69.8 -3.9 153 0.8 7750 12.6 54.7 240 18 9 3.8 2.1 20.6 69.0 -4.4 137 0.7 7500 12.9 55.2 240 16 8 5.0 2.8 20.2 68.3 -4.8 120 0.6 7250 13.2 55.8 235 15 8 4.1 2.2 19.8 67.6 -5.2 103 0.5 7000 13.5 56.3 235 14 7 1.8 1.0 19.3 66.7 -5.7 89 0.5 6750 13.5 56.3 235 14 7 0.7 0.4 18.6 65.5 -6.4 80 0.4 6500 13.6 56.5 235 13 6 2.2 1.2 17.9 64.3 -7.1 70 0.4 6250 13.7 56.7 230 12 6 -1.8 -1.0 17.3 63.2 -7.8 60 0.3 6000 13.3 55.9 230 11 6 -6.8 -3.7 16.2 61.1 -8.9 65 0.3 5750 12.8 55.0 225 10 5 -5.8 -3.2 15.0 58.9 -10.2 73 0.4 5500 12.1 53.8 220 7 4 -14.6 -8.0 13.6 56.4 -11.6 86 0.4 * * * * * * Numerical weather prediction model forecast data valid * * * * * * 05/25/2024 at 0900 MDT | 05/25/2024 at 1200 MDT | CAPE... 0.0 LI... +2.9 | CAPE... +189.6 LI... -0.6 CINH... 0.0 K Index... +4.3 | CINH... -36.1 K Index... +16.5 | 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 -55.1 -67.2 250 63 33 0.9 0.5 | -53.5 -64.3 250 66 34 0.8 0.5 45000 -53.9 -65.0 250 78 40 -0.7 -0.4 | -52.3 -62.1 250 77 40 0.2 0.1 40000 -54.9 -66.8 240 89 46 -0.7 -0.4 | -51.9 -61.4 245 82 42 0.3 0.1 38000 -54.0 -65.2 240 89 46 2.6 1.4 | -51.2 -60.2 240 81 42 1.6 0.9 36000 -52.5 -62.5 240 87 45 2.6 1.4 | -50.3 -58.5 235 78 40 1.6 0.9 34000 -49.8 -57.6 240 83 43 6.9 3.8 | -48.8 -55.8 230 73 38 4.0 2.2 32000 -45.6 -50.1 235 73 38 6.9 3.8 | -46.4 -51.5 230 67 34 4.0 2.2 30000 -41.1 -42.0 235 67 34 8.6 4.7 | -43.2 -45.8 225 62 32 8.5 4.6 29000 -38.5 -37.3 235 66 34 8.6 4.7 | -40.6 -41.1 225 60 31 8.6 4.7 28000 -36.0 -32.8 235 65 33 8.6 4.7 | -38.1 -36.6 225 58 30 8.6 4.7 27000 -33.4 -28.1 230 64 33 8.1 4.4 | -35.5 -31.9 225 57 29 8.4 4.6 26000 -31.0 -23.8 230 61 31 8.0 4.4 | -33.0 -27.4 230 54 28 8.3 4.5 25000 -28.6 -19.5 230 58 30 8.0 4.4 | -30.5 -22.9 230 52 27 8.3 4.5 24000 -26.2 -15.2 230 55 28 7.8 4.3 | -28.1 -18.6 235 50 25 8.1 4.4 23000 -23.9 -11.0 230 53 28 7.7 4.2 | -25.8 -14.4 235 46 24 7.6 4.2 22000 -21.6 -6.9 230 52 27 7.7 4.2 | -23.5 -10.3 235 43 22 7.6 4.2 21000 -19.3 -2.7 235 50 26 7.8 4.3 | -21.2 -6.2 240 40 21 7.7 4.2 20000 -16.9 1.6 235 49 25 7.8 4.3 | -18.9 -2.0 240 38 20 7.8 4.3 19500 -15.7 3.7 235 48 25 7.8 4.3 | -17.8 -0.0 240 37 19 7.8 4.3 19000 -14.6 5.7 240 47 24 7.8 4.3 | -16.6 2.1 240 36 19 7.8 4.3 18500 -13.4 7.9 240 46 24 7.8 4.3 | -14.8 5.4 245 35 18 8.4 4.6 18000 -11.7 10.9 240 45 23 7.7 4.3 | -13.6 7.5 245 36 18 8.4 4.6 17500 -10.5 13.1 240 44 23 7.6 4.2 | -12.3 9.9 245 36 19 8.5 4.7 17000 -9.4 15.1 240 43 22 7.5 4.1 | -11.0 12.2 245 36 18 8.7 4.8 16500 -8.3 17.1 245 42 22 7.5 4.1 | -9.7 14.5 245 35 18 8.7 4.8 16000 -7.2 19.0 245 41 21 7.1 3.9 | -8.5 16.7 245 35 18 8.6 4.7 15500 -6.2 20.8 245 39 20 7.2 3.9 | -7.2 19.0 245 34 17 8.6 4.7 15000 -5.1 22.8 245 38 19 7.0 3.9 | -5.9 21.4 245 33 17 9.0 4.9 14500 -4.1 24.6 245 35 18 7.1 3.9 | -4.6 23.7 245 31 16 9.0 4.9 14000 -3.1 26.4 245 32 16 7.4 4.0 | -3.3 26.1 245 30 15 9.0 4.9 13500 -2.0 28.4 245 30 15 7.5 4.1 | -2.0 28.4 245 29 15 9.0 4.9 13000 -0.9 30.4 250 28 14 7.7 4.2 | -0.7 30.7 250 27 14 9.1 5.0 12500 0.2 32.4 250 26 13 8.0 4.4 | 0.7 33.3 250 26 13 9.2 5.0 12000 1.4 34.5 250 24 12 8.3 4.5 | 2.1 35.8 250 24 12 9.2 5.1 11500 2.7 36.9 255 23 12 9.0 5.0 | 3.4 38.1 250 23 12 9.2 5.1 11000 4.0 39.2 255 23 12 8.5 4.7 | 4.8 40.6 245 21 11 8.8 4.8 10500 5.1 41.2 260 23 12 6.4 3.5 | 6.0 42.8 245 19 10 6.6 3.6 10250 5.6 42.1 260 23 12 8.6 4.7 | 6.5 43.7 245 18 9 9.6 5.3 10000 6.4 43.5 260 22 11 10.1 5.6 | 7.4 45.3 245 18 9 11.2 6.1 9750 7.0 44.6 260 21 11 8.3 4.6 | 8.1 46.6 245 17 9 8.3 4.6 9500 7.6 45.7 260 19 10 7.8 4.3 | 8.7 47.7 245 16 8 7.6 4.2 9250 8.2 46.8 260 18 9 8.4 4.6 | 9.2 48.6 245 14 7 8.5 4.7 9000 8.9 48.0 260 17 8 9.1 5.0 | 9.9 49.8 245 14 7 9.7 5.3 8750 9.5 49.1 260 16 8 8.2 4.5 | 10.6 51.1 245 14 7 9.0 4.9 8500 10.1 50.2 260 14 7 7.2 4.0 | 11.2 52.2 245 12 6 8.2 4.5 8250 10.7 51.3 260 13 7 7.9 4.3 | 11.9 53.4 245 11 6 8.6 4.7 8000 11.2 52.2 260 12 6 5.7 3.1 | 12.5 54.5 245 10 5 7.7 4.2 7750 11.5 52.7 265 10 5 4.1 2.3 | 13.0 55.4 250 8 4 8.9 4.9 7500 11.9 53.4 265 9 4 5.4 3.0 | 13.8 56.8 250 8 4 10.9 6.0 7250 12.2 54.0 270 8 4 4.2 2.3 | 14.6 58.3 250 8 4 9.8 5.4 7000 12.4 54.3 275 6 3 0.6 0.4 | 15.2 59.4 250 7 4 6.7 3.7 6750 12.4 54.3 285 5 3 2.6 1.4 | 15.7 60.3 255 6 3 9.3 5.1 6500 12.8 55.0 295 4 2 5.7 3.1 | 16.6 61.9 255 6 3 13.4 7.3 6250 13.1 55.6 305 4 2 5.5 3.0 | 17.6 63.7 255 6 3 11.0 6.0 6000 13.5 56.3 315 4 2 5.8 3.2 | 18.3 64.9 255 5 3 9.1 5.0 5750 14.0 57.2 325 3 2 9.0 4.9 | 19.0 66.2 265 4 2 9.7 5.3 5500 15.0 59.0 320 3 2 18.7 10.3 | 19.9 67.8 265 4 2 18.3 10.0 05/25/2024 at 1500 MDT | 05/25/2024 at 1800 MDT | CAPE... +341.5 LI... -1.4 | CAPE... +404.9 LI... -1.4 CINH... -10.1 K Index... +21.7 | CINH... -65.8 K Index... +24.4 | 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 -52.7 -62.9 255 64 33 1.0 0.6 | -52.3 -62.1 255 61 31 1.8 1.0 45000 -51.2 -60.2 250 71 36 -0.4 -0.2 | -49.7 -57.5 255 63 32 -0.0 -0.0 40000 -51.6 -60.9 250 73 38 -0.2 -0.1 | -49.8 -57.6 250 67 34 -0.1 -0.0 38000 -51.3 -60.3 250 69 35 0.9 0.5 | -50.4 -58.7 250 64 33 -1.6 -0.9 36000 -50.7 -59.3 245 62 32 0.9 0.5 | -51.4 -60.5 255 58 30 -1.6 -0.9 34000 -49.3 -56.7 245 56 29 6.3 3.4 | -51.5 -60.7 255 51 26 6.6 3.6 32000 -45.4 -49.7 245 51 26 6.4 3.5 | -47.9 -54.2 255 45 23 6.1 3.3 30000 -41.7 -43.1 245 45 23 5.5 3.0 | -43.3 -45.9 260 38 20 8.3 4.6 29000 -40.1 -40.2 245 40 21 5.4 3.0 | -40.8 -41.4 260 35 18 8.4 4.6 28000 -38.5 -37.3 245 34 18 5.4 3.0 | -38.3 -36.9 255 32 17 8.4 4.6 27000 -36.8 -34.2 245 29 15 6.7 3.7 | -35.9 -32.6 255 29 15 8.1 4.4 26000 -34.5 -30.1 245 27 14 7.9 4.3 | -33.5 -28.3 255 28 14 8.0 4.4 25000 -32.1 -25.8 245 26 13 7.9 4.4 | -31.1 -24.0 255 26 13 8.0 4.4 24000 -29.7 -21.5 245 24 12 8.1 4.4 | -28.7 -19.7 250 24 12 8.2 4.5 23000 -27.2 -17.0 245 24 12 8.5 4.7 | -26.2 -15.2 250 24 12 8.3 4.6 22000 -24.7 -12.5 245 24 12 8.5 4.7 | -23.8 -10.8 245 24 13 8.3 4.6 21000 -22.2 -8.0 245 24 12 8.6 4.7 | -21.3 -6.3 245 25 13 8.2 4.5 20000 -19.0 -2.2 245 24 12 8.6 4.7 | -18.9 -2.0 245 25 13 8.2 4.5 19500 -17.7 0.1 245 24 12 8.6 4.7 | -17.7 0.1 245 25 13 8.2 4.5 19000 -16.4 2.5 245 24 12 8.6 4.7 | -16.5 2.3 245 25 13 8.2 4.5 18500 -15.1 4.8 245 24 12 8.8 4.8 | -15.3 4.5 245 25 13 8.2 4.5 18000 -13.8 7.2 245 24 12 8.8 4.9 | -14.1 6.6 245 25 13 8.2 4.5 17500 -12.5 9.5 245 24 12 9.0 4.9 | -12.9 8.8 245 25 13 8.2 4.5 17000 -11.1 12.0 245 23 12 9.1 5.0 | -11.0 12.2 250 25 13 8.4 4.6 16500 -9.8 14.4 245 23 12 9.1 5.0 | -9.8 14.4 250 25 13 8.4 4.6 16000 -8.4 16.9 245 23 12 9.6 5.3 | -8.5 16.7 250 25 13 8.6 4.7 15500 -6.9 19.6 245 23 12 9.5 5.2 | -7.3 18.9 250 25 13 8.6 4.7 15000 -5.5 22.1 245 22 12 9.4 5.1 | -6.0 21.2 255 24 12 9.0 5.0 14500 -4.1 24.6 245 22 11 9.3 5.1 | -4.6 23.7 255 23 12 9.1 5.0 14000 -2.7 27.1 245 22 11 9.4 5.1 | -3.3 26.1 255 23 12 9.1 5.0 13500 -1.3 29.7 245 21 11 9.4 5.1 | -1.9 28.6 255 21 11 9.0 4.9 13000 0.1 32.2 245 20 11 9.3 5.1 | -0.6 30.9 255 20 10 8.9 4.9 12500 1.4 34.5 245 20 10 9.1 5.0 | 0.7 33.3 255 19 10 8.7 4.8 12000 2.8 37.0 245 19 10 9.2 5.0 | 2.0 35.6 255 18 9 8.6 4.7 11500 4.2 39.6 250 18 9 9.4 5.1 | 3.2 37.8 260 16 8 8.5 4.6 11000 5.5 41.9 250 17 9 9.2 5.1 | 4.5 40.1 260 15 8 8.3 4.5 10500 6.8 44.2 255 15 8 8.0 4.4 | 5.6 42.1 260 13 7 6.9 3.8 10250 7.5 45.5 255 15 8 9.9 5.4 | 6.1 43.0 260 13 7 8.7 4.7 10000 8.3 46.9 255 15 8 11.2 6.1 | 6.9 44.4 265 12 6 10.0 5.5 9750 9.1 48.4 255 15 8 10.0 5.5 | 7.6 45.7 265 12 6 8.9 4.9 9500 9.8 49.6 260 15 8 9.9 5.4 | 8.2 46.8 270 11 6 8.8 4.8 9250 10.5 50.9 260 15 8 9.7 5.3 | 8.8 47.8 270 10 5 8.6 4.7 9000 11.2 52.2 260 15 8 9.4 5.2 | 9.4 48.9 275 9 5 7.9 4.3 8750 11.9 53.4 260 15 8 9.7 5.3 | 10.0 50.0 280 9 5 8.0 4.4 8500 12.7 54.9 265 15 8 9.9 5.4 | 10.6 51.1 280 9 4 8.4 4.6 8250 13.4 56.1 265 14 7 10.0 5.5 | 11.2 52.2 285 8 4 8.2 4.5 8000 14.2 57.6 265 14 7 9.3 5.1 | 11.9 53.4 290 8 4 8.6 4.7 7750 14.8 58.6 265 14 7 9.3 5.1 | 12.5 54.5 295 7 4 8.7 4.7 7500 15.6 60.1 265 14 7 10.1 5.5 | 13.1 55.6 300 7 4 8.4 4.6 7250 16.3 61.3 270 14 7 9.9 5.4 | 13.7 56.7 310 7 3 8.4 4.6 7000 17.0 62.6 270 14 7 8.4 4.6 | 14.3 57.7 315 7 3 7.1 3.9 6750 17.6 63.7 275 13 7 9.4 5.1 | 14.8 58.6 320 6 3 8.1 4.4 6500 18.5 65.3 275 13 7 11.4 6.2 | 15.5 59.9 325 6 3 9.8 5.4 6250 19.3 66.7 275 12 6 10.7 5.9 | 16.2 61.2 330 6 3 9.3 5.1 6000 20.0 68.0 275 12 6 9.9 5.4 | 16.9 62.4 335 6 3 9.4 5.2 5750 20.8 69.4 280 11 6 13.3 7.3 | 17.5 63.5 340 6 3 8.4 4.6 5500 22.1 71.8 280 10 5 20.5 11.2 | 18.1 64.6 340 5 2 9.8 5.4 ________________________________________________________________________________ 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