Soaring Guidance
Issued by NWS Denver/Boulder, CO
Issued by NWS Denver/Boulder, CO
501 UXUS97 KBOU 151249 SRGBOU Soaring Forecast National Weather Service Denver/Boulder, Colorado 0649 MDT Sunday, September 15, 2024 This forecast is for Sunday, September 15, 2024: If the trigger temperature of 83.1 F/28.4 C is reached...then Thermal Soaring Index....................... Excellent Maximum rate of lift........................ 888 ft/min (4.5 m/s) Maximum height of thermals.................. 18531 ft MSL (13243 ft AGL) Forecast maximum temperature................... 89.0 F/32.1 C Time of trigger temperature.................... 1145 MDT Time of overdevelopment........................ 1700 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................. 9696 ft MSL (4408 ft AGL) Thermal soaring outlook for Monday 09/16....... 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....................... 17335 ft MSL (12047 ft AGL) Wave soaring outlook for Monday 09/16.......... Fair Remarks... Sunrise/Sunset.................... 06:41:23 / 19:07:29 MDT Total possible sunshine........... 12 hr 26 min 5 sec (746 min 5 sec) Altitude of sun at 12:54:26 MDT... 52.82 degrees Upper air data from numerical model forecast valid on 09/15/2024 at 0600 MDT Freezing level.................. 15454 ft MSL (10166 ft AGL) Convective condensation level... 16257 ft MSL (10969 ft AGL) Lifted condensation level....... 16825 ft MSL (11538 ft AGL) Lifted index.................... -2.7 K index......................... +22.3 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 -60.2 -76.4 245 29 15 1.5 0.8 M M M M M 45000 -58.0 -72.4 245 35 18 1.4 0.8 M M M M M 40000 -55.4 -67.7 220 22 11 6.4 3.5 M M M M M 38000 -51.9 -61.4 215 20 10 5.8 3.2 M M M M M 36000 -48.4 -55.1 210 18 9 5.9 3.2 M M M M M 34000 -44.2 -47.6 215 17 9 7.5 4.1 M M M M M 32000 -39.7 -39.5 220 18 9 7.5 4.1 M M M M M 30000 -35.0 -31.0 220 16 8 7.9 4.3 40.5 104.9 6.7 M M 29000 -32.1 -25.8 220 14 7 7.9 4.3 39.6 103.4 6.1 M M 28000 -29.7 -21.5 220 12 6 8.5 4.6 39.1 102.3 5.8 M M 27000 -27.1 -16.8 220 11 6 9.0 4.9 38.6 101.6 5.5 M M 26000 -24.4 -11.9 220 10 5 9.0 4.9 38.3 101.0 5.3 M M 25000 -21.7 -7.1 215 9 5 9.0 4.9 38.1 100.7 5.2 M M 24000 -19.3 -2.7 205 9 5 7.9 4.3 37.5 99.5 4.7 M M 23000 -16.9 1.6 195 9 5 7.9 4.3 36.8 98.2 4.2 M M 22000 -14.5 5.9 185 10 5 7.7 4.2 36.2 97.2 3.8 M M 21000 -12.6 9.3 190 10 5 6.2 3.4 35.0 95.0 2.7 M M 20000 -10.8 12.6 200 11 6 6.2 3.4 33.7 92.7 1.7 M M 19500 -9.9 14.2 200 11 6 6.2 3.4 33.2 91.7 1.2 M M 19000 -9.0 15.8 205 12 6 6.4 3.5 32.6 90.6 0.6 M M 18500 -8.1 17.4 205 14 7 6.6 3.6 32.0 89.6 0.0 M M 18000 -7.2 19.0 205 15 8 7.3 4.0 31.5 88.7 -0.5 1250 6.4 17500 -6.0 21.2 200 16 8 9.2 5.0 31.3 88.3 -0.8 1199 6.1 17000 -4.7 23.5 200 16 8 9.2 5.0 31.2 88.1 -1.0 1146 5.8 16500 -3.4 25.9 200 16 8 9.5 5.2 31.1 88.0 -1.1 1091 5.5 16000 -1.9 28.6 200 15 8 9.5 5.2 31.0 87.9 -1.1 1033 5.2 15500 -0.5 31.1 200 14 7 9.7 5.3 31.0 87.9 -1.1 975 5.0 15000 1.0 33.8 200 14 7 9.9 5.4 31.0 87.9 -1.1 915 4.6 14500 3.2 37.8 200 13 7 9.7 5.3 31.1 88.0 -1.1 826 4.2 14000 4.7 40.5 200 13 6 9.7 5.3 31.1 87.9 -1.1 768 3.9 13500 6.1 43.0 200 12 6 9.4 5.2 31.1 87.9 -1.1 710 3.6 13000 7.5 45.5 200 10 5 9.1 5.0 31.0 87.7 -1.3 655 3.3 12500 8.8 47.8 200 9 5 9.1 5.0 30.9 87.6 -1.4 600 3.0 12000 10.1 50.2 200 8 4 9.1 5.0 30.8 87.4 -1.5 546 2.8 11500 11.4 52.5 200 8 4 8.9 4.9 30.7 87.2 -1.7 493 2.5 11000 12.6 54.7 200 8 4 7.4 4.1 30.4 86.7 -2.0 443 2.2 10500 13.7 56.7 210 7 4 3.9 2.1 30.1 86.1 -2.4 394 2.0 10250 13.8 56.8 210 7 4 5.2 2.9 29.5 85.1 -2.9 382 1.9 10000 14.6 58.3 215 7 4 11.0 6.0 29.5 85.1 -3.0 354 1.8 9750 15.3 59.5 220 8 4 9.6 5.3 29.5 85.1 -3.0 325 1.7 9500 16.0 60.8 225 8 4 9.2 5.1 29.5 85.1 -3.0 297 1.5 9250 16.5 61.7 230 8 4 6.7 3.6 29.3 84.8 -3.2 272 1.4 9000 17.0 62.6 230 8 4 6.9 3.8 29.1 84.4 -3.5 251 1.3 8750 17.6 63.7 235 9 4 8.4 4.6 28.9 84.1 -3.6 227 1.2 8500 18.1 64.6 240 9 5 7.0 3.9 28.8 83.8 -3.8 202 1.0 8250 18.6 65.5 245 9 5 5.3 2.9 28.5 83.3 -4.1 182 0.9 8000 18.9 66.0 250 9 4 4.0 2.2 28.1 82.6 -4.5 164 0.8 7750 19.2 66.6 255 8 4 4.2 2.3 27.7 81.8 -5.0 149 0.8 7500 19.4 66.9 260 8 4 0.3 0.2 27.2 80.9 -5.5 134 0.7 7250 19.2 66.6 275 7 4 -4.2 -2.3 26.2 79.2 -6.4 133 0.7 7000 18.9 66.0 285 7 4 -3.9 -2.1 25.2 77.3 -7.5 134 0.7 6750 18.6 65.5 300 7 4 -4.2 -2.3 24.1 75.4 -8.5 136 0.7 6500 18.2 64.8 310 8 4 -7.3 -4.0 23.0 73.4 -9.6 140 0.7 6250 17.5 63.5 315 8 4 -9.3 -5.1 21.6 70.8 -11.1 154 0.8 6000 16.8 62.2 320 8 4 -9.0 -4.9 20.1 68.3 -12.6 168 0.9 5750 16.1 61.0 325 8 4 -8.5 -4.7 18.7 65.7 -14.1 183 0.9 5500 15.5 59.9 320 6 3 -6.0 -3.3 17.5 63.4 -15.4 193 1.0 * * * * * * Numerical weather prediction model forecast data valid * * * * * * 09/15/2024 at 0900 MDT | 09/15/2024 at 1200 MDT | CAPE... 0.0 LI... -0.8 | CAPE... +167.2 LI... -0.5 CINH... 0.0 K Index... +21.3 | CINH... -153.2 K Index... +13.8 | 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 -59.6 -75.3 240 28 15 1.6 0.9 | -59.6 -75.3 245 32 17 1.6 0.9 45000 -57.3 -71.1 245 33 17 1.1 0.6 | -57.1 -70.8 240 36 19 1.6 0.9 40000 -55.4 -67.7 225 25 13 5.4 3.0 | -54.6 -66.3 230 35 18 4.5 2.5 38000 -52.3 -62.1 225 24 12 5.1 2.8 | -52.0 -61.6 220 31 16 4.3 2.4 36000 -49.3 -56.7 220 22 11 5.1 2.8 | -49.4 -56.9 210 28 14 4.4 2.4 34000 -44.8 -48.6 220 21 11 8.5 4.6 | -45.0 -49.0 205 27 14 8.5 4.6 32000 -39.7 -39.5 220 20 10 8.5 4.7 | -40.0 -40.0 205 26 14 8.5 4.6 30000 -34.4 -29.9 215 20 10 7.6 4.2 | -34.5 -30.1 205 27 14 7.9 4.3 29000 -32.1 -25.8 210 19 10 7.6 4.2 | -32.2 -26.0 200 27 14 7.9 4.3 28000 -29.9 -21.8 205 19 10 8.2 4.5 | -29.8 -21.6 200 27 14 8.2 4.5 27000 -27.2 -17.0 200 18 9 8.8 4.8 | -27.2 -17.0 195 26 13 8.5 4.7 26000 -24.6 -12.3 190 17 9 8.8 4.8 | -24.7 -12.5 190 25 13 8.5 4.7 25000 -21.9 -7.4 185 16 8 8.9 4.9 | -22.2 -8.0 185 24 12 8.7 4.8 24000 -19.7 -3.5 180 16 8 7.1 3.9 | -20.1 -4.2 190 23 12 6.3 3.5 23000 -17.6 0.3 180 17 9 7.1 3.9 | -18.2 -0.8 195 23 12 6.4 3.5 22000 -15.4 4.3 180 18 9 7.1 3.9 | -16.3 2.7 205 23 12 6.5 3.6 21000 -13.5 7.7 185 18 9 6.6 3.6 | -14.1 6.6 210 22 11 7.8 4.3 20000 -11.6 11.1 190 18 10 6.7 3.7 | -11.8 10.8 215 20 10 7.8 4.3 19500 -10.6 12.9 190 19 10 6.7 3.6 | -10.7 12.7 215 19 10 7.8 4.3 19000 -9.6 14.7 190 18 10 8.4 4.6 | -9.5 14.9 220 18 9 9.4 5.2 18500 -8.3 17.1 190 18 9 8.5 4.7 | -8.0 17.6 215 17 9 9.5 5.2 18000 -7.0 19.4 185 18 9 8.7 4.8 | -6.6 20.1 215 16 8 9.4 5.2 17500 -5.7 21.7 185 17 9 9.2 5.1 | -5.3 22.5 215 16 8 9.1 5.0 17000 -4.4 24.1 185 16 8 9.2 5.1 | -3.9 25.0 215 16 8 9.2 5.0 16500 -3.0 26.6 185 15 8 9.3 5.1 | -2.6 27.3 210 16 8 8.4 4.6 16000 -1.7 28.9 185 15 8 9.3 5.1 | -1.3 29.7 210 16 8 8.4 4.6 15500 -0.3 31.5 185 15 8 9.4 5.2 | -0.1 31.8 205 16 8 8.7 4.8 15000 1.1 34.0 185 14 7 9.5 5.2 | 1.3 34.3 205 16 8 8.9 4.9 14500 3.2 37.8 185 13 7 9.4 5.2 | 3.3 37.9 200 17 9 9.1 5.0 14000 4.6 40.3 190 13 6 9.4 5.1 | 4.6 40.3 200 17 9 9.2 5.0 13500 6.0 42.8 190 12 6 9.1 5.0 | 5.9 42.6 200 17 8 9.2 5.1 13000 7.3 45.1 190 11 6 8.9 4.9 | 7.3 45.1 200 16 8 9.3 5.1 12500 8.6 47.5 190 10 5 8.8 4.8 | 8.7 47.7 200 15 8 9.3 5.1 12000 9.8 49.6 190 9 5 8.5 4.7 | 10.0 50.0 195 14 7 9.2 5.1 11500 11.0 51.8 190 8 4 8.2 4.5 | 11.4 52.5 195 12 6 8.8 4.8 11000 12.1 53.8 195 6 3 6.9 3.8 | 12.4 54.3 195 10 5 6.7 3.7 10500 13.2 55.8 205 4 2 3.8 2.1 | 13.4 56.1 190 8 4 3.8 2.1 10250 13.3 55.9 210 4 2 4.6 2.5 | 13.6 56.5 190 7 4 4.1 2.3 10000 14.0 57.2 220 4 2 9.9 5.4 | 14.1 57.4 195 6 3 8.6 4.7 9750 14.7 58.5 235 3 2 9.3 5.1 | 14.6 58.3 195 5 3 7.6 4.1 9500 15.3 59.5 255 3 2 8.6 4.7 | 15.2 59.4 200 4 2 7.2 4.0 9250 15.9 60.6 270 3 2 6.4 3.5 | 15.6 60.1 210 3 2 6.0 3.3 9000 16.4 61.5 285 3 2 6.3 3.4 | 16.1 61.0 215 2 1 6.9 3.8 8750 16.9 62.4 300 4 2 7.3 4.0 | 16.7 62.1 225 2 1 8.0 4.4 8500 17.4 63.3 310 4 2 5.7 3.1 | 17.3 63.1 255 1 0 7.1 3.9 8250 17.8 64.0 320 5 2 3.8 2.1 | 17.8 64.0 310 1 1 6.4 3.5 8000 18.0 64.4 325 5 3 2.7 1.5 | 18.2 64.8 335 2 1 5.7 3.1 7750 18.2 64.8 330 6 3 2.2 1.2 | 18.6 65.5 340 2 1 4.9 2.7 7500 18.3 64.9 330 7 4 -0.1 -0.0 | 19.0 66.2 345 3 2 5.3 2.9 7250 18.1 64.6 330 7 4 -2.1 -1.1 | 19.4 66.9 335 3 1 5.6 3.1 7000 17.9 64.2 330 7 4 -1.8 -1.0 | 19.7 67.5 330 3 1 6.0 3.3 6750 17.6 63.7 325 8 4 -3.7 -2.1 | 20.2 68.4 325 3 1 8.3 4.5 6500 17.3 63.1 325 7 4 -3.0 -1.7 | 20.8 69.4 320 3 1 10.6 5.8 6250 17.1 62.8 315 6 3 -0.8 -0.4 | 21.6 70.9 315 3 1 11.6 6.4 6000 16.9 62.4 305 5 3 -3.4 -1.8 | 22.5 72.5 315 3 1 10.1 5.5 5750 16.8 62.2 295 5 2 3.7 2.0 | 23.2 73.8 315 3 1 13.8 7.6 5500 17.8 64.0 275 4 2 22.6 12.4 | 24.7 76.5 315 3 1 25.6 14.1 09/15/2024 at 1500 MDT | 09/15/2024 at 1800 MDT | CAPE... +537.6 LI... -2.1 | CAPE... +267.2 LI... -1.6 CINH... -27.5 K Index... +28.3 | CINH... -226.0 K Index... +24.6 | 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 -59.4 -74.9 255 35 18 1.8 1.0 | -59.3 -74.7 265 37 19 2.0 1.1 45000 -56.4 -69.5 250 42 22 2.1 1.2 | -56.3 -69.3 270 46 24 1.7 1.0 40000 -53.3 -63.9 235 47 24 2.7 1.5 | -53.5 -64.3 270 49 25 4.0 2.2 38000 -51.6 -60.9 225 40 21 2.8 1.5 | -51.2 -60.2 260 36 19 3.9 2.1 36000 -49.9 -57.8 210 35 18 2.9 1.6 | -48.8 -55.8 240 25 13 3.9 2.2 34000 -45.6 -50.1 205 33 17 9.1 5.0 | -44.8 -48.6 230 24 12 8.1 4.5 32000 -40.2 -40.4 210 31 16 9.1 5.0 | -39.9 -39.8 230 26 13 8.1 4.5 30000 -34.3 -29.7 210 30 15 8.5 4.7 | -33.9 -29.0 225 25 13 9.1 5.0 29000 -31.8 -25.2 210 30 15 8.6 4.7 | -31.2 -24.2 220 24 12 9.1 5.0 28000 -29.2 -20.6 210 29 15 8.0 4.4 | -28.4 -19.1 215 23 12 8.5 4.7 27000 -27.1 -16.8 210 28 14 7.0 3.9 | -26.3 -15.3 215 24 12 7.2 4.0 26000 -25.0 -13.0 210 27 14 7.1 3.9 | -24.1 -11.4 220 25 13 7.3 4.0 25000 -22.9 -9.2 210 26 13 7.1 3.9 | -21.9 -7.4 220 26 13 7.4 4.1 24000 -20.9 -5.6 215 25 13 6.9 3.8 | -19.8 -3.6 215 27 14 7.1 3.9 23000 -18.9 -2.0 215 24 12 6.9 3.8 | -17.7 0.1 215 27 14 7.1 3.9 22000 -16.8 1.8 220 23 12 7.0 3.8 | -15.6 3.9 210 28 14 7.1 3.9 21000 -14.5 5.9 215 20 10 8.2 4.5 | -13.6 7.5 205 28 14 6.8 3.7 20000 -12.1 10.2 210 16 8 8.2 4.5 | -11.7 10.9 200 28 14 6.9 3.8 19500 -10.9 12.4 205 14 7 8.2 4.5 | -10.7 12.7 195 28 15 6.9 3.8 19000 -9.7 14.5 205 13 7 8.5 4.7 | -9.7 14.5 195 28 15 7.6 4.2 18500 -8.5 16.7 200 13 7 8.6 4.7 | -8.5 16.7 190 28 14 7.9 4.3 18000 -7.2 19.0 200 13 7 8.6 4.7 | -7.4 18.7 190 27 14 8.0 4.4 17500 -5.9 21.4 195 13 7 8.7 4.8 | -6.2 20.8 185 27 14 8.7 4.8 17000 -4.7 23.5 195 14 7 8.7 4.8 | -4.9 23.2 180 28 14 8.6 4.7 16500 -3.4 25.9 195 14 7 8.9 4.9 | -3.7 25.3 175 28 15 9.2 5.0 16000 -2.1 28.2 195 14 7 8.9 4.9 | -1.6 29.1 170 30 15 9.4 5.1 15500 -0.8 30.6 195 15 8 9.0 4.9 | -0.2 31.6 170 30 15 9.5 5.2 15000 1.3 34.3 195 15 8 9.1 5.0 | 1.2 34.2 170 30 15 9.5 5.2 14500 2.6 36.7 195 15 8 9.2 5.0 | 2.6 36.7 170 30 15 9.4 5.2 14000 4.0 39.2 190 15 8 9.2 5.0 | 4.0 39.2 170 29 15 9.4 5.1 13500 5.4 41.7 185 15 8 9.0 4.9 | 5.4 41.7 170 28 14 9.1 5.0 13000 6.7 44.1 180 14 7 8.7 4.8 | 6.7 44.1 170 26 13 8.3 4.6 12500 8.0 46.4 175 13 7 8.9 4.9 | 7.9 46.2 170 23 12 8.1 4.5 12000 9.4 48.9 170 11 6 9.6 5.3 | 9.0 48.2 170 20 10 6.4 3.5 11500 10.8 51.4 165 9 5 9.4 5.1 | 9.9 49.8 170 17 9 6.4 3.5 11000 12.1 53.8 160 7 4 7.9 4.4 | 10.7 51.3 170 12 6 4.9 2.7 10500 13.3 55.9 150 5 3 4.9 2.7 | 11.4 52.5 175 8 4 3.8 2.1 10250 13.5 56.3 150 5 2 5.8 3.2 | 11.6 52.9 175 6 3 4.1 2.2 10000 14.2 57.6 150 4 2 10.7 5.9 | 12.0 53.6 180 3 2 6.4 3.5 9750 14.9 58.8 150 4 2 9.7 5.3 | 12.5 54.5 000 0 0 6.3 3.4 9500 15.6 60.1 150 3 2 9.0 5.0 | 12.9 55.2 345 3 2 6.3 3.5 9250 16.2 61.2 150 3 1 7.8 4.3 | 13.4 56.1 345 6 3 6.4 3.5 9000 16.8 62.2 150 3 1 9.9 5.4 | 13.9 57.0 345 9 5 6.9 3.8 8750 17.6 63.7 155 3 1 11.3 6.2 | 14.4 57.9 345 11 6 7.1 3.9 8500 18.4 65.1 155 2 1 10.6 5.8 | 14.9 58.8 345 14 7 7.1 3.9 8250 19.2 66.6 160 2 1 10.1 5.5 | 15.4 59.7 340 16 8 7.6 4.2 8000 20.0 68.0 160 2 1 9.8 5.4 | 16.0 60.8 335 18 9 6.8 3.7 7750 20.7 69.3 165 2 1 9.8 5.4 | 16.4 61.5 335 20 10 5.4 3.0 7500 21.4 70.5 170 2 1 9.7 5.3 | 16.8 62.2 330 21 11 5.1 2.8 7250 22.1 71.8 175 2 1 9.6 5.2 | 17.1 62.8 325 21 11 5.0 2.7 7000 22.9 73.2 180 2 1 9.7 5.3 | 17.4 63.3 320 21 11 4.9 2.7 6750 23.6 74.5 185 2 1 10.2 5.6 | 17.7 63.9 315 22 11 2.7 1.5 6500 24.4 75.9 190 2 1 10.6 5.8 | 17.9 64.2 310 21 11 6.2 3.4 6250 25.2 77.4 200 1 1 10.9 6.0 | 18.6 65.5 310 20 10 10.5 5.7 6000 26.0 78.8 205 1 1 10.0 5.5 | 19.2 66.6 315 19 10 8.8 4.8 5750 26.8 80.2 215 1 1 13.1 7.2 | 19.9 67.8 315 18 9 10.8 5.9 5500 28.1 82.6 220 1 1 23.0 12.6 | 20.9 69.6 315 16 8 16.2 8.9 ________________________________________________________________________________ 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