Soaring Guidance
Issued by NWS Pueblo, CO
Issued by NWS Pueblo, CO
610 UXUS97 KPUB 251216 SRGPUB Soaring Forecast National Weather Service Pueblo, Colorado 0616 MDT Saturday, May 25, 2024 This forecast is for the Air Force Academy for Saturday, May 25, 2024: If the trigger temperature of 60.2 F/15.7 C is reached...then Thermal Soaring Index....................... Excellent Maximum rate of lift........................ 1210 ft/min (6.1 m/s) Maximum height of thermals.................. 20732 ft MSL (13123 ft AGL) Forecast maximum temperature................... 75.0 F/24.3 C Time of trigger temperature.................... 0930 MDT Time of overdevelopment........................ 1100 MDT Middle/high clouds during soaring window....... None Surface winds during soaring window............ 20 mph or less Height of the -3 thermal index................. 17274 ft MSL (9665 ft AGL) Thermal soaring outlook for Sunday 05/26....... Excellent Wave Soaring Index............................. Not available Remarks... Sunrise/Sunset.................... 05:38:32 / 20:14:07 MDT Total possible sunshine........... 14 hr 35 min 35 sec (875 min 35 sec) Altitude of sun at 12:56:19 MDT... 72.14 degrees Upper air data from numerical model forecast valid on 05/25/2024 at 0600 MDT Freezing level.................. 13114 ft MSL (5505 ft AGL) Convective condensation level... 18971 ft MSL (11362 ft AGL) Lifted condensation level....... 19709 ft MSL (12100 ft AGL) Lifted index.................... -3.1 K index......................... -6.2 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 -56.9 -70.4 250 62 32 1.4 0.8 M M M M M 45000 -55.1 -67.2 250 76 39 -0.6 -0.4 M M M M M 40000 -56.1 -69.0 250 89 46 -0.6 -0.3 M M M M M 38000 -54.1 -65.4 250 84 43 4.3 2.4 M M M M M 36000 -51.6 -60.9 250 76 39 4.3 2.4 M M M M M 34000 -48.3 -54.9 250 67 35 7.0 3.8 M M M M M 32000 -44.1 -47.4 250 58 30 7.0 3.8 M M M M M 30000 -39.7 -39.5 250 53 27 8.0 4.4 28.4 83.2 3.5 M M 29000 -37.3 -35.1 255 54 28 8.0 4.4 27.7 81.9 3.0 M M 28000 -34.9 -30.8 255 54 28 8.0 4.4 27.1 80.8 2.6 M M 27000 -32.5 -26.5 255 54 28 8.4 4.6 26.6 79.8 2.1 M M 26000 -30.0 -22.0 250 52 27 8.3 4.6 25.9 78.7 1.6 M M 25000 -27.5 -17.5 250 50 26 8.3 4.6 25.4 77.8 1.2 M M 24000 -25.0 -13.0 245 49 25 8.9 4.9 25.0 77.1 0.9 M M 23000 -22.2 -8.0 245 48 25 9.2 5.0 24.7 76.5 0.7 M M 22000 -18.8 -1.8 245 48 25 9.1 5.0 24.5 76.1 0.5 M M 21000 -16.3 2.7 245 48 25 7.5 4.1 24.1 75.3 0.1 M M 20000 -14.0 6.8 245 48 25 7.5 4.1 23.3 73.9 -0.6 1130 5.7 19500 -12.9 8.8 245 48 25 7.5 4.1 22.9 73.2 -0.9 1081 5.5 19000 -11.7 10.9 245 48 25 7.6 4.2 22.6 72.6 -1.2 1032 5.2 18500 -10.7 12.7 245 46 24 6.1 3.3 22.1 71.7 -1.6 987 5.0 18000 -9.8 14.4 240 43 22 6.2 3.4 21.5 70.7 -2.2 944 4.8 17500 -8.9 16.0 235 40 20 5.7 3.1 20.9 69.6 -2.7 902 4.6 17000 -8.1 17.4 230 41 21 5.3 2.9 20.1 68.2 -3.5 864 4.4 16500 -7.4 18.7 230 43 22 5.3 2.9 19.4 66.9 -4.2 827 4.2 16000 -6.5 20.3 230 41 21 6.2 3.4 18.7 65.7 -4.9 788 4.0 15500 -5.7 21.7 230 38 19 6.2 3.4 18.1 64.7 -5.5 747 3.8 15000 -4.7 23.5 230 33 17 8.1 4.5 17.7 63.9 -6.0 703 3.6 14500 -3.5 25.7 225 27 14 8.4 4.6 17.5 63.4 -6.4 653 3.3 14000 -2.3 27.9 225 21 11 8.6 4.7 17.3 63.1 -6.6 602 3.1 13500 -1.1 30.0 230 24 12 8.8 4.8 17.1 62.7 -6.9 549 2.8 13000 0.2 32.4 240 26 14 10.6 5.8 16.9 62.5 -7.1 496 2.5 12500 1.6 34.9 245 27 14 6.2 3.4 16.8 62.3 -7.2 440 2.2 12000 2.6 36.7 250 28 14 7.4 4.1 16.4 61.4 -7.7 395 2.0 11750 3.2 37.8 250 28 14 8.9 4.9 16.2 61.2 -7.8 369 1.9 11500 3.9 39.0 255 27 14 8.4 4.6 16.2 61.1 -7.9 342 1.7 11250 4.5 40.1 255 27 14 7.7 4.2 16.0 60.9 -8.1 317 1.6 11000 5.1 41.2 260 26 13 8.1 4.4 15.9 60.6 -8.3 292 1.5 10750 5.7 42.3 260 26 13 8.4 4.6 15.8 60.4 -8.4 266 1.4 10500 6.3 43.3 260 27 14 8.7 4.8 15.7 60.2 -8.5 239 1.2 10250 7.0 44.6 260 27 14 9.3 5.1 15.6 60.1 -8.6 212 1.1 10000 7.7 45.9 260 28 14 9.2 5.0 15.6 60.1 -8.6 184 0.9 9750 8.3 46.9 260 28 15 8.3 4.6 15.5 59.9 -8.8 157 0.8 9500 8.9 48.0 260 29 15 7.8 4.3 15.4 59.7 -8.9 131 0.7 9250 9.5 49.1 255 29 15 8.9 4.9 15.3 59.5 -9.0 105 0.5 9000 10.2 50.4 255 30 15 5.9 3.3 15.1 59.3 -9.2 79 0.4 8750 10.4 50.7 255 29 15 1.7 0.9 14.6 58.3 -9.7 65 0.3 8500 10.4 50.7 250 28 14 -1.8 -1.0 13.9 57.1 -10.4 57 0.3 8250 10.4 50.7 250 26 13 8.6 4.7 13.2 55.8 -11.2 49 0.3 8000 11.1 52.0 245 24 12 -4.4 -2.4 13.2 55.7 -11.3 22 0.1 7750 8.7 47.7 245 16 8 -58.5 -32.1 10.1 50.1 -14.4 87 0.4 7500 M M M M M M M M M M M M 7250 M M M M M M M M M M M M 7000 M M M M M M M M M M M M 6750 M M M M M M M M M M M M * * * * * * Numerical weather prediction model forecast data valid * * * * * * 05/25/2024 at 0900 MDT | 05/25/2024 at 1200 MDT | CAPE... 0.0 LI... +1.7 | CAPE... +30.5 LI... +0.6 CINH... 0.0 K Index... -10.4 | CINH... -9.9 K Index... -2.5 | 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 -56.1 -69.0 250 62 32 1.3 0.7 | -55.3 -67.5 250 70 36 1.4 0.8 45000 -54.4 -65.9 250 76 39 -0.5 -0.3 | -53.3 -63.9 250 82 42 0.1 0.1 40000 -55.3 -67.5 245 93 48 -0.5 -0.3 | -53.0 -63.4 245 93 48 0.2 0.1 38000 -53.7 -64.7 245 93 48 3.6 2.0 | -51.8 -61.2 240 92 47 2.6 1.4 36000 -51.5 -60.7 245 89 46 3.6 2.0 | -50.3 -58.5 240 88 45 2.6 1.4 34000 -48.7 -55.7 245 83 43 6.3 3.4 | -48.2 -54.8 235 83 43 5.1 2.8 32000 -44.9 -48.8 245 71 37 6.2 3.4 | -45.1 -49.2 235 77 40 5.2 2.8 30000 -40.7 -41.3 240 62 32 8.6 4.7 | -41.4 -42.5 230 70 36 8.5 4.6 29000 -38.1 -36.6 240 59 31 8.6 4.7 | -38.8 -37.8 230 65 33 8.5 4.7 28000 -35.5 -31.9 235 57 29 8.6 4.7 | -36.3 -33.3 225 60 31 8.5 4.7 27000 -32.9 -27.2 230 55 28 9.0 5.0 | -33.8 -28.8 225 57 29 8.1 4.4 26000 -30.3 -22.5 230 54 28 9.0 4.9 | -31.4 -24.5 225 58 30 7.9 4.4 25000 -27.6 -17.7 230 53 27 9.0 4.9 | -28.4 -19.1 230 59 31 7.9 4.4 24000 -24.9 -12.8 230 52 27 8.2 4.5 | -26.1 -15.0 230 60 31 8.0 4.4 23000 -22.6 -8.7 230 51 26 7.6 4.2 | -23.6 -10.5 230 56 29 8.0 4.4 22000 -19.8 -3.6 230 49 25 7.6 4.2 | -21.2 -6.2 230 53 27 8.0 4.4 21000 -17.4 0.7 230 48 25 7.9 4.4 | -18.9 -2.0 230 49 25 7.3 4.0 20000 -15.0 5.0 230 45 23 8.0 4.4 | -16.7 1.9 235 45 23 7.4 4.1 19500 -13.8 7.2 230 44 23 8.0 4.4 | -15.5 4.1 235 43 22 7.4 4.1 19000 -12.6 9.3 230 43 22 7.9 4.4 | -14.4 6.1 240 41 21 7.4 4.1 18500 -11.4 11.5 230 41 21 8.2 4.5 | -13.3 8.1 240 39 20 7.5 4.1 18000 -10.2 13.6 235 39 20 8.2 4.5 | -12.2 10.0 245 38 20 7.5 4.1 17500 -8.9 16.0 235 38 19 8.6 4.7 | -11.1 12.0 245 37 19 7.8 4.3 17000 -7.6 18.3 235 34 17 9.0 4.9 | -9.8 14.4 250 37 19 8.3 4.5 16500 -6.2 20.8 230 30 16 9.0 4.9 | -8.6 16.5 250 38 19 8.2 4.5 16000 -5.0 23.0 230 30 16 8.0 4.4 | -7.3 18.9 255 38 19 9.0 4.9 15500 -3.8 25.2 230 33 17 8.1 4.5 | -6.0 21.2 250 37 19 9.0 4.9 15000 -2.6 27.3 230 35 18 7.1 3.9 | -4.7 23.5 250 35 18 8.1 4.5 14500 -1.6 29.1 230 37 19 6.8 3.7 | -3.6 25.5 245 31 16 8.1 4.4 14000 -0.5 31.1 235 38 20 5.7 3.1 | -2.5 27.5 245 28 14 8.6 4.7 13500 0.1 32.2 235 39 20 5.0 2.7 | -1.2 29.8 245 26 13 9.4 5.1 13000 0.8 33.4 235 39 20 7.9 4.4 | 0.1 32.2 245 23 12 14.0 7.7 12500 1.8 35.2 240 37 19 4.2 2.3 | 1.9 35.4 245 23 12 6.5 3.6 12000 2.4 36.3 240 34 17 5.7 3.1 | 3.1 37.6 245 23 12 8.6 4.7 11750 2.9 37.2 240 32 17 7.9 4.3 | 3.9 39.0 245 23 12 11.5 6.3 11500 3.5 38.3 240 31 16 7.3 4.0 | 4.7 40.5 245 22 11 10.4 5.7 11250 3.9 39.0 240 31 16 6.2 3.4 | 5.4 41.7 245 22 11 8.7 4.8 11000 4.4 39.9 245 30 16 6.5 3.6 | 6.1 43.0 245 22 11 9.2 5.1 10750 4.8 40.6 245 30 16 6.0 3.3 | 6.8 44.2 245 22 11 9.4 5.2 10500 5.2 41.4 250 31 16 6.3 3.5 | 7.5 45.5 245 22 11 9.7 5.3 10250 5.8 42.4 255 31 16 7.8 4.3 | 8.2 46.8 245 22 11 9.7 5.3 10000 6.4 43.5 255 30 15 8.7 4.8 | 9.0 48.2 245 21 11 9.8 5.4 9750 7.0 44.6 255 28 15 9.5 5.2 | 9.7 49.5 245 21 11 10.2 5.6 9500 7.8 46.0 255 27 14 9.9 5.4 | 10.5 50.9 245 21 11 10.5 5.8 9250 8.5 47.3 255 26 13 10.1 5.6 | 11.3 52.3 245 21 11 10.1 5.5 9000 9.3 48.7 255 25 13 10.6 5.8 | 12.0 53.6 245 20 11 10.0 5.5 8750 10.1 50.2 255 24 12 10.4 5.7 | 12.8 55.0 245 20 10 10.8 5.9 8500 10.8 51.4 255 22 12 10.7 5.8 | 13.6 56.5 245 20 10 11.9 6.5 8250 11.6 52.9 255 21 11 9.4 5.1 | 15.2 59.4 245 19 10 13.3 7.3 8000 12.3 54.1 255 20 10 12.4 6.8 | 16.7 62.1 245 17 9 29.7 16.3 7750 13.6 56.5 250 16 8 22.3 12.2 | 19.0 66.2 240 15 8 24.6 13.5 7500 M M M M M M M | M M M M M M M 7250 M M M M M M M | M M M M M M M 7000 M M M M M M M | M M M M M M M 6750 M M M M M M M | M M M M M M M 05/25/2024 at 1500 MDT | 05/25/2024 at 1800 MDT | CAPE... +308.0 LI... -1.3 | CAPE... +421.0 LI... -1.7 CINH... 0.0 K Index... +25.6 | CINH... -0.1 K Index... +23.8 | 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 -53.7 -64.7 250 69 36 1.0 0.5 | -53.0 -63.4 255 60 31 1.4 0.8 45000 -52.3 -62.1 250 81 42 0.2 0.1 | -51.0 -59.8 255 70 36 0.7 0.4 40000 -51.8 -61.2 245 89 46 0.3 0.2 | -49.9 -57.8 255 75 38 0.7 0.4 38000 -51.3 -60.3 245 84 43 1.1 0.6 | -49.8 -57.6 255 72 37 0.1 0.0 36000 -50.7 -59.3 245 76 39 1.1 0.6 | -49.7 -57.5 250 67 34 0.1 0.0 34000 -48.9 -56.0 240 70 36 7.0 3.9 | -48.7 -55.7 255 60 31 4.8 2.6 32000 -44.6 -48.3 245 65 33 7.2 3.9 | -45.9 -50.6 255 52 27 4.8 2.6 30000 -40.5 -40.9 245 60 31 6.3 3.5 | -42.4 -44.3 260 45 23 8.1 4.4 29000 -38.6 -37.5 245 58 30 6.3 3.5 | -39.9 -39.8 260 42 22 8.1 4.5 28000 -36.7 -34.1 250 56 29 6.3 3.5 | -37.5 -35.5 265 40 20 8.1 4.5 27000 -34.8 -30.6 250 54 28 6.4 3.5 | -35.1 -31.2 265 37 19 8.0 4.4 26000 -32.4 -26.3 250 51 26 6.5 3.6 | -32.7 -26.9 265 35 18 8.0 4.4 25000 -30.4 -22.7 255 48 25 6.6 3.6 | -30.3 -22.5 265 34 17 8.0 4.4 24000 -28.4 -19.1 255 46 24 8.0 4.4 | -27.9 -18.2 265 32 16 7.8 4.3 23000 -26.0 -14.8 255 43 22 8.4 4.6 | -25.6 -14.1 260 31 16 7.7 4.2 22000 -23.5 -10.3 255 39 20 8.4 4.6 | -23.4 -10.1 255 30 15 7.7 4.2 21000 -20.9 -5.6 255 36 18 9.4 5.2 | -20.5 -4.9 250 30 15 8.6 4.7 20000 -18.2 -0.8 255 31 16 9.4 5.1 | -17.9 -0.2 255 30 15 8.6 4.7 19500 -16.8 1.8 255 28 15 9.4 5.1 | -16.7 1.9 255 30 15 8.6 4.7 19000 -15.4 4.3 255 26 13 9.5 5.2 | -15.4 4.3 255 30 16 8.6 4.7 18500 -14.1 6.6 255 24 12 8.6 4.7 | -14.1 6.6 255 30 15 8.8 4.8 18000 -12.8 9.0 255 23 12 8.6 4.7 | -12.8 9.0 255 28 14 8.8 4.8 17500 -11.6 11.1 250 22 11 8.8 4.8 | -11.5 11.3 255 26 13 9.0 4.9 17000 -10.2 13.6 250 21 11 9.1 5.0 | -10.2 13.6 255 25 13 9.1 5.0 16500 -8.9 16.0 250 21 11 9.0 4.9 | -8.9 16.0 255 25 13 9.2 5.0 16000 -7.5 18.5 250 21 11 10.1 5.5 | -7.5 18.5 255 24 12 9.4 5.2 15500 -6.0 21.2 250 21 11 10.0 5.5 | -6.2 20.8 255 23 12 9.4 5.1 15000 -4.5 23.9 250 20 10 9.7 5.3 | -4.8 23.4 255 22 11 9.7 5.3 14500 -3.0 26.6 250 20 10 9.7 5.3 | -3.3 26.1 255 22 11 9.9 5.4 14000 -1.6 29.1 250 20 10 10.4 5.7 | -1.8 28.8 255 22 11 10.6 5.8 13500 0.1 32.2 250 20 10 11.4 6.3 | -0.1 31.8 255 22 11 11.2 6.2 13000 1.9 35.4 245 19 10 5.8 3.2 | 1.6 34.9 255 22 11 6.8 3.8 12500 2.8 37.0 245 19 10 11.2 6.2 | 2.6 36.7 255 21 11 10.7 5.9 12000 4.3 39.7 245 19 10 10.3 5.6 | 4.0 39.2 255 21 11 10.5 5.7 11750 5.1 41.2 245 19 10 12.0 6.6 | 4.9 40.8 255 21 11 11.9 6.5 11500 6.0 42.8 245 18 9 10.6 5.8 | 5.7 42.3 255 21 11 9.8 5.4 11250 6.7 44.1 245 18 9 8.6 4.7 | 6.4 43.5 255 20 11 8.3 4.5 11000 7.3 45.1 245 18 9 9.1 5.0 | 7.0 44.6 255 20 10 8.7 4.8 10750 8.0 46.4 245 18 9 9.6 5.3 | 7.7 45.9 255 20 10 9.6 5.3 10500 8.8 47.8 245 18 9 9.9 5.5 | 8.4 47.1 250 20 10 10.3 5.6 10250 9.5 49.1 245 18 9 9.4 5.2 | 9.2 48.6 250 20 10 9.9 5.4 10000 10.2 50.4 245 18 9 9.3 5.1 | 9.9 49.8 250 20 10 9.9 5.4 9750 11.7 53.1 240 17 9 11.4 6.2 | 10.7 51.3 250 19 10 10.2 5.6 9500 12.5 54.5 240 17 9 10.0 5.5 | 11.4 52.5 250 19 10 10.4 5.7 9250 13.2 55.8 240 17 9 8.8 4.8 | 12.2 54.0 250 19 10 10.2 5.6 9000 13.9 57.0 240 17 9 10.3 5.6 | 13.0 55.4 250 19 10 10.2 5.6 8750 14.8 58.6 240 16 8 11.6 6.4 | 13.7 56.7 250 18 9 10.3 5.7 8500 15.6 60.1 240 16 8 10.4 5.7 | 14.5 58.1 250 18 9 10.7 5.9 8250 16.3 61.3 240 15 8 9.8 5.4 | 15.3 59.5 250 17 9 9.7 5.3 8000 17.2 63.0 240 14 7 15.1 8.3 | 16.0 60.8 250 17 9 9.9 5.4 7750 18.8 65.8 235 13 7 31.1 17.1 | 18.2 64.8 245 13 6 22.1 12.1 7500 M M M M M M M | M M M M M M M 7250 M M M M M M M | M M M M M M M 7000 M M M M M M M | M M M M M M M 6750 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). 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 Air Force Academy in Colorado Springs, Colorado at North Latitude: 38 deg 58 min 48.000 sec West Longitude: 104 deg 49 min 12.000 sec Elevation: 6572 feet (2003 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. CIN (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