Soaring Guidance
Issued by NWS Pueblo, CO
Issued by NWS Pueblo, CO
764 UXUS97 KPUB 171220 SRGPUB Soaring Forecast National Weather Service Pueblo, Colorado 0620 MDT Saturday, August 17, 2024 This forecast is for the Air Force Academy for Saturday, August 17, 2024: If the trigger temperature of 79.5 F/26.4 C is reached...then Thermal Soaring Index....................... Excellent Maximum rate of lift........................ 1670 ft/min (8.5 m/s) Maximum height of thermals.................. 24260 ft MSL (16652 ft AGL) Forecast maximum temperature................... 92.0 F/33.8 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................. 20653 ft MSL (13044 ft AGL) Thermal soaring outlook for Sunday 08/18....... Excellent Wave Soaring Index............................. Not available Remarks... Sunrise/Sunset.................... 06:15:24 / 19:51:00 MDT Total possible sunshine........... 13 hr 35 min 36 sec (815 min 36 sec) Altitude of sun at 13:03:12 MDT... 64.08 degrees Upper air data from numerical model forecast valid on 08/17/2024 at 0600 MDT Freezing level.................. 16908 ft MSL (9300 ft AGL) Convective condensation level... 18530 ft MSL (10922 ft AGL) Lifted condensation level....... 20350 ft MSL (12742 ft AGL) Lifted index.................... -4.7 K index......................... +5.1 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 -64.0 -83.2 260 22 11 2.6 1.4 M M M M M 45000 -58.9 -74.0 265 32 16 4.8 2.7 M M M M M 40000 -50.7 -59.3 270 40 21 6.6 3.6 M M M M M 38000 -46.8 -52.2 280 42 22 6.6 3.6 M M M M M 36000 -42.7 -44.9 285 44 23 7.4 4.0 M M M M M 34000 -38.1 -36.6 290 43 22 7.7 4.2 M M M M M 32000 -33.5 -28.3 290 41 21 7.8 4.3 M M M M M 30000 -28.9 -20.0 295 41 21 7.7 4.2 39.7 103.4 4.9 M M 29000 -26.6 -15.9 300 42 21 7.7 4.2 38.9 102.1 4.4 M M 28000 -24.4 -11.9 300 42 21 6.3 3.4 38.1 100.7 3.9 M M 27000 -22.5 -8.5 305 41 21 6.4 3.5 36.8 98.2 2.8 M M 26000 -20.5 -4.9 305 40 20 6.4 3.5 35.6 96.0 1.8 M M 25000 -18.6 -1.5 305 39 20 6.4 3.5 34.5 94.0 0.9 M M 24000 -16.7 1.9 305 34 18 6.4 3.5 33.2 91.7 -0.2 1658 8.4 23000 -14.3 6.3 305 28 14 6.4 3.5 31.7 89.0 -1.4 1549 7.9 22000 -12.2 10.0 305 23 12 8.2 4.5 30.7 87.3 -2.3 1457 7.4 21000 -9.8 14.4 300 19 10 8.0 4.4 30.1 86.1 -2.9 1355 6.9 20000 -7.4 18.7 285 15 8 8.0 4.4 29.5 85.1 -3.4 1253 6.4 19500 -6.2 20.8 280 13 7 8.7 4.8 29.3 84.7 -3.6 1202 6.1 19000 -4.8 23.4 270 13 7 9.1 5.0 29.2 84.5 -3.7 1147 5.8 18500 -3.5 25.7 265 12 6 9.2 5.0 29.1 84.3 -3.9 1092 5.5 18000 -2.3 27.9 255 12 6 7.3 4.0 28.8 83.8 -4.2 1041 5.3 17500 -1.2 29.8 250 12 6 7.7 4.2 28.4 83.2 -4.6 994 5.0 17000 -0.1 31.8 240 13 6 8.0 4.4 28.1 82.6 -5.0 947 4.8 16500 1.0 33.8 235 12 6 8.2 4.5 27.8 82.1 -5.4 898 4.6 16000 2.1 35.8 230 11 6 8.4 4.6 27.6 81.6 -5.7 849 4.3 15500 3.4 38.1 230 10 5 9.1 5.0 27.4 81.4 -5.9 795 4.0 15000 4.8 40.6 230 9 5 8.9 4.9 27.3 81.1 -6.0 739 3.8 14500 6.2 43.2 235 8 4 9.8 5.4 27.2 81.0 -6.1 683 3.5 14000 7.6 45.7 235 7 4 9.9 5.4 27.2 81.0 -6.2 625 3.2 13500 9.0 48.2 240 6 3 9.0 4.9 27.2 81.0 -6.3 568 2.9 13000 10.3 50.5 240 6 3 9.2 5.1 27.1 80.7 -6.5 515 2.6 12500 11.8 53.2 245 5 3 10.3 5.7 27.1 80.9 -6.5 455 2.3 12000 13.3 55.9 245 5 3 10.1 5.6 27.2 80.9 -6.6 397 2.0 11750 14.0 57.2 245 5 3 9.1 5.0 27.2 80.9 -6.6 368 1.9 11500 14.6 58.3 250 5 2 8.1 4.4 27.1 80.7 -6.7 342 1.7 11250 15.2 59.4 250 5 3 8.4 4.6 26.9 80.5 -6.9 317 1.6 11000 15.8 60.4 250 5 3 8.5 4.7 26.8 80.3 -7.0 292 1.5 10750 16.4 61.5 250 5 3 8.6 4.7 26.8 80.2 -7.2 267 1.4 10500 17.0 62.6 250 6 3 8.4 4.6 26.7 80.0 -7.3 241 1.2 10250 17.5 63.5 250 7 3 7.1 3.9 26.5 79.7 -7.5 218 1.1 10000 18.0 64.4 250 8 4 6.6 3.6 26.3 79.3 -7.8 196 1.0 9750 18.4 65.1 250 9 4 6.6 3.6 26.0 78.9 -8.1 175 0.9 9500 18.9 66.0 250 10 5 7.2 3.9 25.8 78.5 -8.4 154 0.8 9250 19.3 66.7 250 11 5 5.4 3.0 25.6 78.1 -8.7 133 0.7 9000 19.6 67.3 250 11 6 3.1 1.7 25.1 77.3 -9.3 119 0.6 8750 19.7 67.5 245 11 6 3.6 2.0 24.7 76.4 -9.8 107 0.5 8500 19.9 67.8 245 11 6 2.7 1.5 24.2 75.5 -10.4 94 0.5 8250 20.0 68.0 250 11 6 -0.0 -0.0 23.5 74.4 -11.1 85 0.4 8000 19.8 67.6 250 11 6 -4.4 -2.4 22.7 72.8 -12.1 84 0.4 7750 18.9 66.0 255 11 5 -23.9 -13.1 21.0 69.9 -13.7 103 0.5 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 * * * * * * 08/17/2024 at 0900 MDT | 08/17/2024 at 1200 MDT | CAPE... +589.3 LI... -1.4 | CAPE... +143.9 LI... +0.3 CINH... -75.7 K Index... +18.0 | CINH... -7.1 K Index... +21.2 | 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 -63.5 -82.3 270 20 10 2.8 1.5 | -63.7 -82.7 260 16 8 2.8 1.5 45000 -58.5 -73.3 270 28 14 4.3 2.4 | -58.6 -73.5 265 26 14 4.5 2.5 40000 -51.0 -59.8 265 39 20 6.8 3.7 | -50.9 -59.6 270 42 22 6.5 3.6 38000 -46.8 -52.2 270 42 22 6.8 3.7 | -47.0 -52.6 270 47 24 6.5 3.6 36000 -42.7 -44.9 270 44 23 7.6 4.1 | -43.1 -45.6 270 50 26 7.5 4.1 34000 -38.0 -36.4 280 42 21 7.8 4.3 | -38.4 -37.1 275 44 23 7.8 4.3 32000 -33.3 -27.9 285 40 20 7.9 4.3 | -33.7 -28.7 275 38 20 8.0 4.4 30000 -28.9 -20.0 295 36 19 7.4 4.0 | -29.2 -20.6 280 31 16 7.5 4.1 29000 -26.7 -16.1 300 35 18 7.4 4.0 | -27.0 -16.6 285 28 14 7.5 4.1 28000 -24.5 -12.1 305 33 17 6.3 3.5 | -24.8 -12.6 290 25 13 7.0 3.9 27000 -22.6 -8.7 310 32 16 6.4 3.5 | -22.6 -8.7 295 24 13 7.1 3.9 26000 -20.7 -5.3 315 31 16 6.5 3.5 | -20.5 -4.9 300 23 12 7.1 3.9 25000 -18.7 -1.7 315 29 15 6.4 3.5 | -18.4 -1.1 305 23 12 7.1 3.9 24000 -16.8 1.8 315 24 13 6.4 3.5 | -15.7 3.7 300 19 10 7.1 3.9 23000 -14.4 6.1 310 18 10 6.4 3.5 | -13.6 7.5 295 17 9 7.1 3.9 22000 -12.3 9.9 300 14 7 8.1 4.4 | -11.4 11.5 285 15 8 7.8 4.3 21000 -10.0 14.0 280 12 6 8.0 4.4 | -9.1 15.6 265 14 7 7.8 4.3 20000 -7.6 18.3 260 12 6 8.0 4.4 | -6.7 19.9 250 15 8 7.8 4.3 19500 -6.4 20.5 250 13 7 7.9 4.3 | -5.6 21.9 240 15 8 6.5 3.6 19000 -5.3 22.5 245 14 7 8.0 4.4 | -4.8 23.4 240 16 8 6.4 3.5 18500 -4.2 24.4 240 15 8 8.3 4.6 | -3.9 25.0 235 17 9 6.9 3.8 18000 -3.0 26.6 240 16 8 8.6 4.7 | -2.9 26.8 235 17 9 8.2 4.5 17500 -1.8 28.8 240 17 9 8.7 4.8 | -1.7 28.9 235 16 8 8.3 4.6 17000 -0.6 30.9 235 17 9 9.1 5.0 | -0.6 30.9 230 15 8 9.0 5.0 16500 0.8 33.4 235 15 8 9.2 5.0 | 0.8 33.4 230 13 7 9.2 5.0 16000 2.2 36.0 235 14 7 9.2 5.0 | 2.1 35.8 230 11 6 9.1 5.0 15500 3.6 38.5 235 12 6 9.1 5.0 | 3.5 38.3 230 9 5 9.0 4.9 15000 4.9 40.8 235 11 6 9.1 5.0 | 4.8 40.6 235 8 4 8.9 4.9 14500 6.3 43.3 235 9 5 9.3 5.1 | 6.1 43.0 245 6 3 9.4 5.2 14000 7.7 45.9 235 8 4 9.3 5.1 | 7.5 45.5 260 4 2 9.4 5.2 13500 9.1 48.4 240 7 4 8.8 4.9 | 8.9 48.0 280 4 2 9.1 5.0 13000 10.3 50.5 245 6 3 9.0 5.0 | 10.2 50.4 285 4 2 9.6 5.3 12500 11.8 53.2 245 5 3 9.6 5.3 | 11.7 53.1 290 4 2 10.6 5.8 12000 13.2 55.8 255 5 2 9.8 5.4 | 13.3 55.9 295 3 2 11.0 6.0 11750 13.9 57.0 260 5 2 8.8 4.8 | 14.1 57.4 295 3 2 8.5 4.7 11500 14.5 58.1 265 5 2 8.4 4.6 | 14.6 58.3 300 3 2 8.2 4.5 11250 15.1 59.2 270 5 2 9.0 4.9 | 15.4 59.7 300 3 2 10.4 5.7 11000 15.8 60.4 275 5 2 9.0 4.9 | 16.1 61.0 300 3 2 10.0 5.5 10750 16.4 61.5 280 5 2 8.4 4.6 | 16.9 62.4 300 3 2 9.4 5.2 10500 17.1 62.8 285 5 3 10.7 5.9 | 17.6 63.7 305 3 2 12.1 6.6 10250 17.9 64.2 285 5 3 9.5 5.2 | 18.6 65.5 305 3 2 11.3 6.2 10000 18.4 65.1 290 6 3 6.6 3.6 | 19.3 66.7 305 3 2 8.3 4.6 9750 18.9 66.0 295 6 3 6.8 3.7 | 19.9 67.8 310 3 2 8.3 4.5 9500 19.4 66.9 295 6 3 9.1 5.0 | 20.6 69.1 310 3 2 11.6 6.3 9250 20.2 68.4 295 8 4 9.0 4.9 | 21.6 70.9 310 3 2 12.0 6.6 9000 20.6 69.1 290 9 5 5.8 3.2 | 22.3 72.1 310 3 2 8.6 4.7 8750 21.0 69.8 285 10 5 6.7 3.7 | 23.0 73.4 315 3 1 9.0 4.9 8500 21.4 70.5 285 11 6 4.7 2.6 | 23.6 74.5 315 3 1 10.1 5.5 8250 21.6 70.9 285 12 6 3.2 1.7 | 24.5 76.1 315 3 1 11.8 6.5 8000 21.8 71.2 280 12 6 4.0 2.2 | 25.3 77.5 315 3 1 9.4 5.2 7750 22.0 71.6 280 11 6 6.7 3.7 | 26.0 78.8 320 3 1 14.8 8.1 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 08/17/2024 at 1500 MDT | 08/17/2024 at 1800 MDT | CAPE... +413.6 LI... -1.4 | CAPE... +238.7 LI... -0.6 CINH... -6.9 K Index... +29.2 | CINH... -43.3 K Index... +26.0 | 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 -63.8 -82.8 265 16 8 2.4 1.3 | -64.6 -84.3 270 17 9 1.8 1.0 45000 -58.9 -74.0 275 29 15 4.9 2.7 | -59.8 -75.6 280 32 17 5.7 3.1 40000 -50.7 -59.3 280 42 22 6.2 3.4 | -50.5 -58.9 285 42 21 6.5 3.6 38000 -47.0 -52.6 275 42 22 6.2 3.4 | -46.6 -51.9 280 42 22 6.5 3.6 36000 -43.2 -45.8 270 42 22 7.9 4.3 | -42.6 -44.7 275 43 22 8.3 4.6 34000 -38.3 -36.9 265 38 20 8.2 4.5 | -37.5 -35.5 270 42 21 8.6 4.7 32000 -33.4 -28.1 255 34 18 8.3 4.5 | -32.3 -26.1 265 40 21 8.5 4.7 30000 -29.0 -20.2 260 30 16 7.1 3.9 | -28.1 -18.6 255 37 19 6.9 3.8 29000 -26.9 -16.4 260 28 15 7.2 3.9 | -26.0 -14.8 250 35 18 6.9 3.8 28000 -24.7 -12.5 260 26 14 7.2 3.9 | -23.9 -11.0 250 33 17 6.8 3.7 27000 -22.5 -8.5 265 24 12 7.2 3.9 | -21.9 -7.4 250 30 15 6.8 3.8 26000 -20.4 -4.7 270 22 11 7.2 3.9 | -19.8 -3.6 250 27 14 6.9 3.8 25000 -18.2 -0.8 275 20 10 7.0 3.9 | -17.7 0.1 250 24 12 7.2 3.9 24000 -15.7 3.7 270 20 10 7.0 3.8 | -14.9 5.2 250 25 13 7.4 4.0 23000 -13.6 7.5 265 20 10 7.0 3.9 | -12.7 9.1 250 25 13 7.4 4.0 22000 -11.5 11.3 260 19 10 7.7 4.3 | -10.6 12.9 250 24 13 7.1 3.9 21000 -9.3 15.3 255 17 9 7.9 4.4 | -8.5 16.7 245 20 11 7.4 4.1 20000 -7.1 19.2 250 15 8 8.3 4.6 | -6.4 20.5 245 16 8 8.0 4.4 19500 -6.0 21.2 245 13 7 7.7 4.2 | -5.3 22.5 245 14 7 8.3 4.6 19000 -4.9 23.2 245 9 4 7.6 4.2 | -4.1 24.6 245 11 6 8.4 4.6 18500 -3.8 25.2 245 5 2 7.7 4.2 | -3.0 26.6 240 8 4 8.5 4.6 18000 -2.6 27.3 240 3 1 9.1 5.0 | -1.7 28.9 235 5 3 8.8 4.8 17500 -1.2 29.8 240 2 1 9.0 5.0 | -0.4 31.3 210 3 1 8.8 4.8 17000 0.1 32.2 235 1 1 9.4 5.1 | 0.8 33.4 150 2 1 8.7 4.8 16500 1.5 34.7 205 1 0 9.5 5.2 | 2.1 35.8 130 3 2 8.6 4.7 16000 3.0 37.4 135 1 0 9.3 5.1 | 3.4 38.1 120 4 2 8.7 4.8 15500 4.3 39.7 115 1 1 9.0 4.9 | 4.7 40.5 115 6 3 8.9 4.9 15000 5.7 42.3 110 2 1 8.9 4.9 | 6.0 42.8 115 7 3 8.9 4.9 14500 7.0 44.6 110 2 1 9.6 5.3 | 7.4 45.3 120 7 4 8.8 4.8 14000 8.5 47.3 110 3 1 9.6 5.3 | 8.7 47.7 120 8 4 8.8 4.9 13500 9.8 49.6 115 3 2 8.8 4.8 | 10.0 50.0 125 9 4 8.7 4.8 13000 11.1 52.0 120 4 2 9.4 5.2 | 11.3 52.3 130 9 5 9.0 4.9 12500 12.7 54.9 120 4 2 10.2 5.6 | 12.8 55.0 135 10 5 9.1 5.0 12000 14.1 57.4 125 5 2 10.1 5.5 | 14.1 57.4 140 10 5 8.7 4.8 11750 14.9 58.8 125 5 3 9.5 5.2 | 14.7 58.5 145 10 5 8.7 4.8 11500 15.6 60.1 125 5 3 9.3 5.1 | 15.4 59.7 145 10 5 8.6 4.7 11250 16.3 61.3 125 5 3 9.8 5.4 | 16.0 60.8 145 11 5 8.5 4.6 11000 17.0 62.6 125 6 3 9.8 5.4 | 16.6 61.9 150 11 6 8.5 4.7 10750 17.7 63.9 125 6 3 9.5 5.2 | 17.2 63.0 150 11 6 8.4 4.6 10500 18.5 65.3 125 6 3 10.8 5.9 | 17.8 64.0 150 11 6 8.9 4.9 10250 19.3 66.7 130 6 3 10.7 5.9 | 18.5 65.3 155 12 6 8.8 4.9 10000 20.0 68.0 130 6 3 9.3 5.1 | 19.1 66.4 155 12 6 8.1 4.5 9750 20.7 69.3 130 6 3 9.6 5.3 | 19.7 67.5 160 12 6 8.5 4.7 9500 21.4 70.5 130 6 3 9.8 5.4 | 20.3 68.5 160 13 7 7.9 4.3 9250 22.2 72.0 130 6 3 10.3 5.7 | 20.9 69.6 160 13 7 9.0 5.0 9000 23.0 73.4 130 6 3 10.3 5.7 | 21.6 70.9 160 13 7 10.5 5.7 8750 23.7 74.7 130 7 3 10.3 5.6 | 22.4 72.3 160 13 7 10.2 5.6 8500 24.5 76.1 130 7 3 10.4 5.7 | 23.1 73.6 160 13 7 10.3 5.7 8250 25.3 77.5 130 7 3 11.0 6.0 | 23.9 75.0 160 13 7 10.5 5.8 8000 26.1 79.0 130 7 3 9.6 5.2 | 24.7 76.5 165 13 7 10.1 5.6 7750 26.9 80.4 130 7 3 14.8 8.1 | 25.5 77.9 165 13 7 12.1 6.7 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