Soaring Guidance
Issued by NWS Pueblo, CO
Issued by NWS Pueblo, CO
776 UXUS97 KPUB 161206 SRGPUB Soaring Forecast National Weather Service Pueblo, Colorado 0606 MDT Tuesday, July 16, 2024 This forecast is for the Air Force Academy for Tuesday, July 16, 2024: If the trigger temperature of 74.2 F/23.4 C is reached...then Thermal Soaring Index....................... Fair Maximum rate of lift........................ 759 ft/min (3.9 m/s) Maximum height of thermals.................. 17773 ft MSL (10153 ft AGL) Forecast maximum temperature................... 82.0 F/28.2 C Time of trigger temperature.................... 0900 MDT Time of overdevelopment........................ 1300 MDT Middle/high clouds during soaring window....... Broken/overcast opaque middle Surface winds during soaring window............ Between 20 mph and 30 mph Height of the -3 thermal index................. 13465 ft MSL (5845 ft AGL) Thermal soaring outlook for Wednesday 07/17.... Poor Wave Soaring Index............................. Not available Remarks... Sunrise/Sunset.................... 05:47:30 / 20:23:24 MDT Total possible sunshine........... 14 hr 35 min 54 sec (875 min 54 sec) Altitude of sun at 13:05:27 MDT... 72.16 degrees Upper air data from numerical model forecast valid on 07/16/2024 at 0600 MDT Freezing level.................. 16609 ft MSL (8989 ft AGL) Convective condensation level... 16281 ft MSL (8661 ft AGL) Lifted condensation level....... 16788 ft MSL (9168 ft AGL) Lifted index.................... -4.5 K index......................... +29.0 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 -62.5 -80.5 305 15 8 1.5 0.8 M M M M M 45000 -58.4 -73.1 295 17 9 4.9 2.7 M M M M M 40000 -50.3 -58.5 260 20 10 6.2 3.4 M M M M M 38000 -46.6 -51.9 250 27 14 6.2 3.4 M M M M M 36000 -42.9 -45.2 245 34 17 6.9 3.8 M M M M M 34000 -38.3 -36.9 255 30 15 7.5 4.1 M M M M M 32000 -33.8 -28.8 260 27 14 8.0 4.4 M M M M M 30000 -29.3 -20.7 265 24 13 7.6 4.1 39.3 102.8 9.0 M M 29000 -27.1 -16.8 270 23 12 7.6 4.2 38.6 101.4 8.5 M M 28000 -24.8 -12.6 270 23 12 6.6 3.6 37.8 100.0 7.9 M M 27000 -22.9 -9.2 270 23 12 6.5 3.6 36.4 97.6 6.9 M M 26000 -21.0 -5.8 275 24 12 6.5 3.6 35.2 95.4 6.0 M M 25000 -19.1 -2.4 275 25 13 6.5 3.6 34.2 93.5 5.2 M M 24000 -17.1 1.2 275 24 12 6.7 3.7 33.0 91.3 4.2 M M 23000 -14.7 5.5 280 23 12 6.8 3.7 31.6 88.9 3.0 M M 22000 -12.7 9.1 280 23 12 8.5 4.7 30.8 87.4 2.2 M M 21000 -10.2 13.6 285 21 11 8.6 4.7 30.3 86.5 1.7 M M 20000 -7.7 18.1 285 19 10 8.6 4.7 29.9 85.9 1.3 M M 19500 -6.4 20.5 290 18 9 8.2 4.5 29.8 85.6 1.2 M M 19000 -5.3 22.5 285 17 9 7.6 4.2 29.4 84.9 0.8 M M 18500 -4.2 24.4 285 16 8 7.6 4.2 29.1 84.3 0.5 M M 18000 -3.1 26.4 285 15 8 7.5 4.1 28.7 83.6 0.1 M M 17500 -2.0 28.4 285 14 7 7.6 4.1 28.3 83.0 -0.2 929 4.7 17000 -0.9 30.4 285 12 6 7.7 4.2 28.0 82.3 -0.6 881 4.5 16500 0.3 32.5 290 11 6 8.0 4.4 27.7 81.8 -0.9 832 4.2 16000 1.4 34.5 290 10 5 8.0 4.4 27.4 81.3 -1.2 783 4.0 15500 2.6 36.7 290 9 5 8.6 4.7 27.1 80.9 -1.5 733 3.7 15000 3.8 38.8 285 8 4 8.7 4.8 26.9 80.5 -1.8 682 3.5 14500 5.0 41.0 280 8 4 7.4 4.1 26.7 80.1 -2.1 632 3.2 14000 6.0 42.8 265 8 4 7.2 3.9 26.3 79.3 -2.5 586 3.0 13500 7.0 44.6 250 9 5 7.4 4.1 25.9 78.6 -3.0 541 2.7 13000 8.2 46.8 245 9 5 7.7 4.2 25.6 78.0 -3.3 492 2.5 12500 9.3 48.7 245 10 5 8.0 4.4 25.2 77.4 -3.6 444 2.3 12000 10.5 50.9 245 9 5 8.7 4.8 25.0 77.1 -3.9 392 2.0 11750 11.2 52.2 245 9 4 7.8 4.3 24.9 76.9 -4.0 366 1.9 11500 11.7 53.1 245 8 4 6.4 3.5 24.7 76.5 -4.2 343 1.7 11250 12.2 54.0 245 8 4 7.6 4.2 24.5 76.1 -4.5 321 1.6 11000 12.8 55.0 245 8 4 8.4 4.6 24.4 75.9 -4.6 295 1.5 10750 13.4 56.1 245 8 4 8.6 4.7 24.3 75.7 -4.7 269 1.4 10500 14.0 57.2 245 7 4 7.2 3.9 24.2 75.5 -4.8 243 1.2 10250 14.5 58.1 245 7 4 7.3 4.0 23.9 75.0 -5.1 221 1.1 10000 15.1 59.2 245 7 4 8.8 4.8 23.8 74.9 -5.2 195 1.0 9750 15.8 60.4 245 7 4 8.6 4.7 23.7 74.7 -5.3 168 0.9 9500 16.4 61.5 245 7 3 7.9 4.3 23.6 74.5 -5.4 142 0.7 9250 16.9 62.4 245 7 4 6.5 3.6 23.4 74.2 -5.6 118 0.6 9000 17.4 63.3 250 7 4 6.4 3.5 23.2 73.7 -5.9 97 0.5 8750 17.9 64.2 250 8 4 6.7 3.7 22.9 73.2 -6.1 75 0.4 8500 18.4 65.1 250 8 4 6.2 3.4 22.7 72.8 -6.4 53 0.3 8250 18.8 65.8 255 8 4 3.7 2.0 22.3 72.2 -6.8 34 0.2 8000 18.5 65.3 255 8 4 -13.0 -7.1 21.4 70.5 -7.7 34 0.2 7750 16.6 61.9 260 7 4 -36.4 -20.0 18.7 65.7 -10.5 86 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 * * * * * * 07/16/2024 at 0900 MDT | 07/16/2024 at 1200 MDT | CAPE... +501.2 LI... -2.6 | CAPE... +987.3 LI... -3.5 CINH... -45.7 K Index... +28.9 | CINH... -0.2 K Index... +31.1 | 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 -62.3 -80.1 315 14 7 1.6 0.9 | -62.4 -80.3 320 11 6 1.4 0.7 45000 -57.9 -72.2 305 16 8 5.4 3.0 | -58.2 -72.8 300 17 9 5.5 3.0 40000 -49.4 -56.9 280 20 10 5.2 2.9 | -49.6 -57.3 280 24 12 5.2 2.8 38000 -46.3 -51.3 265 27 14 5.2 2.9 | -46.5 -51.7 270 30 16 5.2 2.8 36000 -43.2 -45.8 260 35 18 6.4 3.5 | -43.4 -46.1 265 38 19 6.4 3.5 34000 -38.5 -37.3 260 34 18 7.8 4.3 | -38.7 -37.7 265 36 18 7.8 4.3 32000 -33.9 -29.0 260 33 17 8.3 4.6 | -34.0 -29.2 260 33 17 8.3 4.6 30000 -29.5 -21.1 260 30 16 7.4 4.0 | -29.3 -20.7 265 29 15 7.9 4.3 29000 -27.3 -17.1 260 29 15 7.4 4.0 | -27.0 -16.6 270 27 14 7.9 4.3 28000 -25.1 -13.2 260 27 14 7.1 3.9 | -24.7 -12.5 270 26 13 7.0 3.8 27000 -23.0 -9.4 260 27 14 7.1 3.9 | -22.6 -8.7 270 25 13 6.9 3.8 26000 -20.9 -5.6 260 26 13 7.1 3.9 | -20.6 -5.1 270 24 12 6.9 3.8 25000 -18.8 -1.8 260 25 13 6.9 3.8 | -18.5 -1.3 265 23 12 7.0 3.8 24000 -16.9 1.6 265 24 12 6.4 3.5 | -16.0 3.2 270 22 11 7.0 3.8 23000 -14.5 5.9 265 23 12 6.4 3.5 | -13.9 7.0 270 21 11 7.0 3.9 22000 -12.6 9.3 270 21 11 7.3 4.0 | -11.9 10.6 275 21 11 6.7 3.7 21000 -10.5 13.1 270 20 10 7.4 4.1 | -9.9 14.2 275 20 10 6.7 3.7 20000 -8.3 17.1 275 18 10 7.5 4.1 | -8.0 17.6 275 19 10 6.8 3.7 19500 -7.2 19.0 275 18 9 8.0 4.4 | -7.0 19.4 275 19 10 6.9 3.8 19000 -6.0 21.2 280 17 9 8.6 4.7 | -6.0 21.2 275 18 9 7.0 3.9 18500 -4.8 23.4 285 16 8 8.7 4.8 | -4.9 23.2 270 17 9 7.0 3.9 18000 -3.5 25.7 290 16 8 8.5 4.7 | -3.9 25.0 270 17 9 7.3 4.0 17500 -2.3 27.9 290 15 8 8.5 4.6 | -2.9 26.8 275 17 9 7.4 4.0 17000 -1.1 30.0 290 14 7 7.9 4.4 | -1.8 28.8 280 17 9 7.6 4.1 16500 -0.0 32.0 290 12 6 7.2 3.9 | -0.7 30.7 285 16 8 7.8 4.3 16000 1.0 33.8 295 10 5 7.2 3.9 | 0.5 32.9 290 15 8 7.8 4.3 15500 2.0 35.6 295 9 5 7.5 4.1 | 1.5 34.7 290 14 7 6.6 3.6 15000 3.1 37.6 305 8 4 7.4 4.1 | 2.4 36.3 290 12 6 6.7 3.7 14500 4.2 39.6 310 7 4 8.3 4.6 | 3.4 38.1 295 9 5 7.4 4.1 14000 5.4 41.7 310 6 3 8.5 4.6 | 4.4 39.9 310 6 3 7.6 4.1 13500 6.6 43.9 315 5 3 7.6 4.2 | 5.4 41.7 345 5 2 8.3 4.6 13000 7.6 45.7 315 5 2 7.4 4.1 | 6.7 44.1 020 5 3 9.0 4.9 12500 8.9 48.0 315 4 2 8.8 4.9 | 8.1 46.6 030 6 3 10.2 5.6 12000 10.1 50.2 315 4 2 8.4 4.6 | 9.7 49.5 030 6 3 11.0 6.0 11750 10.7 51.3 315 4 2 7.7 4.2 | 10.5 50.9 030 6 3 10.1 5.5 11500 11.2 52.2 315 4 2 7.0 3.9 | 11.2 52.2 030 6 3 9.0 5.0 11250 11.8 53.2 315 4 2 7.9 4.3 | 11.9 53.4 030 6 3 9.6 5.3 11000 12.4 54.3 315 4 2 8.3 4.5 | 12.6 54.7 030 6 3 9.9 5.4 10750 13.0 55.4 315 4 2 8.6 4.7 | 13.3 55.9 035 6 3 9.9 5.4 10500 13.6 56.5 315 4 2 7.0 3.8 | 14.1 57.4 035 6 3 9.7 5.3 10250 14.1 57.4 315 4 2 6.9 3.8 | 14.8 58.6 035 7 3 9.6 5.3 10000 14.7 58.5 310 3 2 8.2 4.5 | 15.5 59.9 035 7 3 9.7 5.3 9750 15.2 59.4 310 3 2 8.2 4.5 | 16.2 61.2 035 7 3 10.1 5.5 9500 15.8 60.4 305 3 1 6.9 3.8 | 17.0 62.6 035 7 3 8.4 4.6 9250 16.3 61.3 295 2 1 7.8 4.3 | 17.6 63.7 035 7 3 8.9 4.9 9000 17.0 62.6 295 1 1 10.4 5.7 | 18.3 64.9 035 7 3 11.3 6.2 8750 17.8 64.0 285 1 0 10.4 5.7 | 19.2 66.6 035 7 4 11.0 6.0 8500 18.5 65.3 000 0 0 10.0 5.5 | 20.0 68.0 040 7 4 11.1 6.1 8250 19.2 66.6 000 0 0 9.9 5.4 | 20.8 69.4 040 7 4 12.3 6.7 8000 20.1 68.2 000 0 0 14.4 7.9 | 21.9 71.4 040 7 4 19.4 10.7 7750 21.4 70.5 150 1 0 20.3 11.1 | 23.7 74.7 040 7 3 28.5 15.6 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 07/16/2024 at 1500 MDT | 07/16/2024 at 1800 MDT | CAPE... +420.4 LI... -2.4 | CAPE... +536.4 LI... -2.4 CINH... -3.6 K Index... +30.9 | CINH... -109.4 K Index... +27.4 | 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 -62.4 -80.3 300 15 8 1.8 1.0 | -63.0 -81.4 315 15 8 1.5 0.8 45000 -58.3 -72.9 295 25 13 4.1 2.3 | -58.9 -74.0 290 19 10 5.1 2.8 40000 -51.1 -60.0 270 35 18 7.9 4.3 | -50.3 -58.5 245 29 15 6.9 3.8 38000 -46.4 -51.5 260 36 19 7.9 4.3 | -46.1 -51.0 240 33 17 7.0 3.8 36000 -41.7 -43.1 250 38 20 8.0 4.4 | -41.9 -43.4 235 37 19 7.6 4.2 34000 -36.2 -33.2 250 30 16 8.1 4.5 | -37.1 -34.8 240 35 18 8.0 4.4 32000 -31.3 -24.3 250 23 12 8.8 4.8 | -32.4 -26.3 250 34 18 8.5 4.7 30000 -26.8 -16.2 255 17 9 7.7 4.2 | -27.9 -18.2 255 32 17 7.4 4.1 29000 -24.5 -12.1 255 15 7 7.8 4.3 | -25.7 -14.3 260 31 16 7.4 4.1 28000 -22.3 -8.1 260 12 6 6.7 3.7 | -23.5 -10.3 265 31 16 6.8 3.7 27000 -20.3 -4.5 265 10 5 6.8 3.7 | -21.5 -6.7 270 31 16 6.8 3.8 26000 -18.3 -0.9 275 7 4 6.8 3.7 | -19.5 -3.1 275 30 16 6.9 3.8 25000 -16.3 2.7 295 6 3 6.7 3.7 | -17.5 0.5 280 31 16 6.7 3.7 24000 -14.4 6.1 310 5 3 6.5 3.6 | -15.7 3.7 285 30 15 6.2 3.4 23000 -12.5 9.5 335 5 2 6.5 3.6 | -13.4 7.9 290 28 15 6.2 3.4 22000 -10.6 12.9 355 5 3 6.3 3.5 | -11.6 11.1 295 28 14 6.9 3.8 21000 -8.4 16.9 010 6 3 6.1 3.3 | -9.6 14.7 300 27 14 7.0 3.8 20000 -6.7 19.9 025 6 3 6.1 3.4 | -7.5 18.5 305 26 13 7.0 3.8 19500 -5.8 21.6 030 7 3 6.0 3.3 | -6.5 20.3 305 25 13 7.2 3.9 19000 -5.0 23.0 035 7 4 5.9 3.3 | -5.4 22.3 310 24 12 7.4 4.1 18500 -4.1 24.6 045 7 4 5.9 3.2 | -4.4 24.1 310 23 12 7.5 4.1 18000 -3.3 26.1 050 8 4 6.3 3.4 | -3.3 26.1 310 22 11 7.3 4.0 17500 -2.4 27.7 055 8 4 6.3 3.4 | -2.3 27.9 315 21 11 7.3 4.0 17000 -1.5 29.3 060 8 4 6.1 3.3 | -1.2 29.8 315 21 11 7.5 4.1 16500 -0.7 30.7 060 9 5 5.8 3.2 | -0.1 31.8 315 20 10 7.7 4.2 16000 0.2 32.4 060 9 5 5.8 3.2 | 1.0 33.8 310 19 10 7.7 4.2 15500 1.1 34.0 060 10 5 7.7 4.2 | 2.1 35.8 310 19 10 7.5 4.1 15000 2.2 36.0 055 10 5 7.7 4.2 | 3.2 37.8 305 18 9 7.5 4.1 14500 3.2 37.8 055 10 5 6.0 3.3 | 4.3 39.7 305 18 9 8.1 4.4 14000 4.0 39.2 055 9 5 5.8 3.2 | 5.6 42.1 305 17 9 8.1 4.5 13500 4.8 40.6 055 9 5 6.5 3.6 | 6.8 44.2 305 17 9 7.3 4.0 13000 5.8 42.4 050 8 4 6.9 3.8 | 7.8 46.0 305 16 8 6.9 3.8 12500 6.7 44.1 050 8 4 6.8 3.7 | 9.0 48.2 305 15 8 8.5 4.6 12000 7.8 46.0 045 7 4 8.6 4.7 | 10.1 50.2 310 14 7 7.4 4.0 11750 8.5 47.3 045 7 4 7.4 4.1 | 10.7 51.3 310 13 7 7.4 4.1 11500 8.9 48.0 045 6 3 5.9 3.2 | 11.2 52.2 310 12 6 6.9 3.8 11250 9.4 48.9 040 6 3 7.4 4.0 | 11.7 53.1 310 12 6 5.9 3.3 11000 9.9 49.8 040 6 3 8.4 4.6 | 12.1 53.8 315 11 6 5.8 3.2 10750 10.5 50.9 040 5 3 7.8 4.3 | 12.5 54.5 315 11 5 5.6 3.1 10500 11.1 52.0 035 5 3 9.3 5.1 | 12.9 55.2 320 10 5 6.5 3.6 10250 11.8 53.2 035 5 3 8.7 4.8 | 13.4 56.1 325 9 5 5.0 2.7 10000 12.4 54.3 030 5 2 6.9 3.8 | 13.6 56.5 330 8 4 2.8 1.6 9750 12.9 55.2 025 4 2 7.0 3.9 | 13.8 56.8 335 7 4 3.6 2.0 9500 13.4 56.1 020 4 2 8.4 4.6 | 14.1 57.4 340 7 4 2.8 1.6 9250 14.1 57.4 020 4 2 10.2 5.6 | 14.2 57.6 345 6 3 2.0 1.1 9000 14.9 58.8 015 3 2 9.8 5.4 | 14.3 57.7 350 5 3 2.1 1.1 8750 15.6 60.1 010 3 2 9.5 5.2 | 14.3 57.7 355 4 2 1.9 1.0 8500 16.3 61.3 005 3 2 10.3 5.7 | 14.4 57.9 005 3 2 3.1 1.7 8250 17.1 62.8 360 3 1 11.3 6.2 | 14.6 58.3 340 2 1 5.3 2.9 8000 17.9 64.2 355 3 1 10.2 5.6 | 14.9 58.8 300 2 1 7.6 4.2 7750 18.6 65.5 350 2 1 9.9 5.4 | 15.6 60.1 280 3 1 15.1 8.3 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