


Soaring Guidance
Issued by NWS Denver/Boulder, CO
Issued by NWS Denver/Boulder, CO
852 UXUS97 KBOU 130253 SRGBOU Soaring Forecast National Weather Service Denver/Boulder, Colorado 2053 MDT Sunday, October 12, 2025 This forecast is for Monday, October 13, 2025: If the trigger temperature of 57.3 F/14.0 C is reached...then Thermal Soaring Index....................... Poor Maximum rate of lift........................ 77 ft/min (0.4 m/s) Maximum height of thermals.................. 11855 ft MSL (6562 ft AGL) Forecast maximum temperature................... 64.0 F/18.2 C Time of trigger temperature.................... 1145 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................. 10164 ft MSL (4870 ft AGL) Thermal soaring outlook for Tuesday 10/14...... Good Wave Soaring Index............................. Excellent Wave Soaring Index trend (to 1800 MDT)......... Becoming fair after 1200 as stab Height of stable layer (12-18K ft MSL)......... 11932 ft MSL (6639 ft AGL) Weak PVA/NVA (through 1800 MDT)................ Weak PVA Potential height of wave....................... 40455 ft MSL (35162 ft AGL) Wave soaring outlook for Tuesday 10/14......... Poor Remarks... Southwest flow aloft increasing Sunrise/Sunset.................... 07:08:19 / 18:22:50 MDT Total possible sunshine........... 11 hr 14 min 31 sec (674 min 31 sec) Altitude of sun at 12:45:34 MDT... 42.03 degrees Upper air data from numerical model forecast valid on 10/13/2025 at 0600 MDT Freezing level.................. 10230 ft MSL (4937 ft AGL) Convective condensation level... 22712 ft MSL (17419 ft AGL) Lifted condensation level....... 16652 ft MSL (11358 ft AGL) Lifted index.................... +11.5 K index......................... -9.4 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 -64.5 -84.1 230 86 44 1.3 0.7 M M M M M 45000 -60.9 -77.6 235 118 61 6.5 3.5 M M M M M 40000 -51.2 -60.2 235 125 64 5.5 3.0 M M M M M 38000 -49.2 -56.6 235 112 58 3.2 1.8 M M M M M 36000 -47.3 -53.1 235 100 51 3.2 1.8 M M M M M 34000 -44.2 -47.6 235 89 46 6.8 3.7 M M M M M 32000 -40.1 -40.2 235 79 41 6.8 3.7 M M M M M 30000 -35.1 -31.2 235 72 37 7.9 4.4 41.3 106.3 17.8 M M 29000 -32.8 -27.0 235 69 36 7.9 4.4 40.5 105.0 17.4 M M 28000 -30.4 -22.7 235 67 34 8.0 4.4 39.9 103.9 17.2 M M 27000 -28.1 -18.6 235 65 33 7.7 4.2 39.2 102.5 16.8 M M 26000 -25.8 -14.4 235 64 33 7.7 4.2 38.3 101.0 16.3 M M 25000 -23.5 -10.3 235 62 32 7.7 4.2 37.6 99.7 15.9 M M 24000 -21.3 -6.3 235 60 31 6.3 3.4 36.7 98.1 15.4 M M 23000 -19.4 -2.9 230 55 29 6.4 3.5 35.4 95.7 14.5 M M 22000 -17.5 0.5 230 51 26 6.4 3.5 34.2 93.6 13.7 M M 21000 -15.6 3.9 225 48 25 6.1 3.4 33.0 91.5 12.8 M M 20000 -13.7 7.3 225 47 24 6.2 3.4 31.7 89.1 11.8 M M 19500 -12.8 9.0 230 46 24 6.2 3.4 31.1 88.0 11.4 M M 19000 -11.9 10.6 230 45 23 6.1 3.3 30.5 87.0 10.9 M M 18500 -10.9 12.4 230 45 23 7.7 4.2 30.1 86.1 10.6 M M 18000 -9.7 14.5 230 44 23 7.5 4.1 29.7 85.4 10.3 M M 17500 -8.6 16.5 230 44 23 6.7 3.7 29.3 84.8 10.0 M M 17000 -7.7 18.1 230 43 22 6.0 3.3 28.6 83.5 9.5 M M 16500 -6.8 19.8 230 42 21 5.9 3.3 28.0 82.4 9.0 M M 16000 -6.1 21.0 230 40 21 4.1 2.3 27.2 80.9 8.3 M M 15500 -5.5 22.1 230 38 20 4.3 2.4 26.3 79.3 7.5 M M 15000 -4.5 23.9 230 34 18 5.0 2.8 25.0 77.0 6.3 M M 14500 -3.8 25.2 235 32 16 5.1 2.8 24.2 75.6 5.6 M M 14000 -3.1 26.4 235 30 15 4.2 2.3 23.3 74.0 4.8 M M 13500 -2.6 27.3 230 29 15 4.6 2.5 22.5 72.4 4.0 M M 13000 -2.1 28.2 230 28 14 1.9 1.0 21.4 70.5 3.0 M M 12500 -2.0 28.4 225 27 14 2.2 1.2 20.1 68.2 1.7 M M 12000 -1.9 28.6 220 25 13 -1.1 -0.6 18.7 65.7 0.3 M M 11500 -2.2 28.0 215 21 11 -2.0 -1.1 16.9 62.5 -1.5 472 2.4 11000 -1.9 28.6 205 19 10 7.0 3.8 15.6 60.1 -2.7 450 2.3 10500 -0.6 30.9 200 19 10 9.2 5.0 15.3 59.6 -2.8 395 2.0 10250 0.1 32.2 195 19 10 4.4 2.4 15.2 59.4 -2.9 368 1.9 10000 0.2 32.4 195 19 10 4.5 2.5 14.6 58.3 -3.4 355 1.8 9750 0.9 33.6 190 19 10 9.5 5.2 14.5 58.2 -3.5 327 1.7 9500 1.6 34.9 185 19 10 8.8 4.8 14.4 58.0 -3.5 299 1.5 9250 2.3 36.1 185 19 10 7.1 3.9 14.4 57.9 -3.6 271 1.4 9000 2.7 36.9 180 19 10 5.8 3.2 14.1 57.3 -3.9 251 1.3 8750 3.2 37.8 175 19 10 7.5 4.1 13.8 56.9 -4.1 228 1.2 8500 3.8 38.8 175 20 10 7.6 4.2 13.7 56.6 -4.3 203 1.0 8250 4.4 39.9 170 20 10 7.0 3.9 13.5 56.3 -4.5 179 0.9 8000 4.9 40.8 170 20 10 6.9 3.8 13.3 55.9 -4.7 157 0.8 7750 5.4 41.7 165 20 10 8.2 4.5 13.1 55.5 -4.9 133 0.7 7500 6.1 43.0 165 20 10 8.9 4.9 13.0 55.4 -5.0 106 0.5 7250 6.7 44.1 160 20 10 8.5 4.7 12.9 55.3 -5.1 80 0.4 7000 7.4 45.3 160 20 10 8.6 4.7 12.8 55.1 -5.2 53 0.3 6750 8.0 46.4 155 19 10 8.4 4.6 12.7 54.9 -5.3 27 0.1 6500 8.6 47.5 155 18 9 7.1 3.9 12.6 54.7 -5.5 2 0.0 6250 9.0 48.2 155 17 9 6.1 3.3 12.3 54.2 -5.8 M M 6000 9.5 49.1 150 15 8 7.0 3.9 12.1 53.8 -6.1 M M 5750 9.9 49.8 150 13 7 4.3 2.4 11.8 53.3 -6.4 M M 5500 9.9 49.8 145 9 5 -3.5 -1.9 11.1 52.1 -7.1 M M * * * * * * Numerical weather prediction model forecast data valid * * * * * * 10/13/2025 at 0900 MDT | 10/13/2025 at 1200 MDT | CAPE... 0.0 LI... +6.8 | CAPE... 0.0 LI... +6.1 CINH... 0.0 K Index... +12.4 | CINH... 0.0 K Index... +14.1 | 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 -65.0 -85.0 235 85 44 2.3 1.3 | -65.0 -85.0 235 84 43 2.7 1.5 45000 -60.2 -76.4 235 108 56 6.0 3.3 | -60.0 -76.0 235 110 56 5.5 3.0 40000 -51.2 -60.2 230 118 61 5.3 2.9 | -51.8 -61.2 235 124 64 5.3 2.9 38000 -48.6 -55.5 230 109 56 4.4 2.4 | -48.8 -55.8 235 115 59 5.0 2.7 36000 -45.9 -50.6 230 99 51 4.4 2.4 | -45.8 -50.4 235 107 55 5.0 2.7 34000 -42.9 -45.2 230 89 46 5.6 3.1 | -42.6 -44.7 235 92 48 4.6 2.5 32000 -39.1 -38.4 230 78 40 5.6 3.1 | -39.8 -39.6 230 77 40 4.5 2.5 30000 -34.9 -30.8 230 71 37 8.0 4.4 | -35.3 -31.5 225 67 34 9.6 5.3 29000 -32.5 -26.5 230 69 36 8.0 4.4 | -32.4 -26.3 225 64 33 9.6 5.3 28000 -30.1 -22.2 230 67 35 8.0 4.4 | -29.5 -21.1 220 61 31 9.7 5.3 27000 -27.8 -18.0 230 65 34 7.7 4.2 | -27.1 -16.8 220 58 30 7.5 4.1 26000 -25.5 -13.9 230 64 33 7.7 4.2 | -24.8 -12.6 215 56 29 7.5 4.1 25000 -23.2 -9.8 230 63 32 7.7 4.2 | -22.6 -8.7 215 54 28 7.5 4.1 24000 -21.0 -5.8 230 62 32 6.6 3.6 | -20.4 -4.7 210 52 27 7.5 4.1 23000 -19.1 -2.4 230 61 32 6.7 3.7 | -18.2 -0.8 210 51 26 7.6 4.2 22000 -17.1 1.2 230 61 31 6.8 3.7 | -16.0 3.2 205 49 25 7.5 4.1 21000 -15.2 4.6 230 59 30 6.6 3.6 | -14.1 6.6 205 47 24 5.1 2.8 20000 -13.3 8.1 230 53 28 6.6 3.6 | -12.6 9.3 210 42 22 5.1 2.8 19500 -12.3 9.9 230 51 26 6.7 3.6 | -11.8 10.8 210 40 21 5.2 2.8 19000 -11.4 11.5 230 48 25 6.8 3.7 | -11.1 12.0 210 38 20 5.1 2.8 18500 -10.6 12.9 230 46 24 4.5 2.5 | -9.9 14.2 215 36 19 5.5 3.0 18000 -9.8 14.4 230 44 23 4.7 2.6 | -9.1 15.6 215 35 18 5.5 3.0 17500 -9.1 15.6 235 42 22 5.4 3.0 | -8.3 17.1 220 34 18 5.7 3.1 17000 -8.3 17.1 230 40 21 5.9 3.2 | -7.4 18.7 220 34 17 5.7 3.1 16500 -7.0 19.4 230 37 19 6.5 3.6 | -6.6 20.1 225 33 17 6.6 3.6 16000 -6.0 21.2 230 35 18 6.8 3.7 | -5.6 21.9 225 32 17 7.0 3.9 15500 -5.0 23.0 230 33 17 6.8 3.7 | -4.6 23.7 225 32 16 7.0 3.9 15000 -4.0 24.8 225 32 16 6.6 3.6 | -3.6 25.5 220 31 16 6.8 3.7 14500 -3.1 26.4 225 31 16 6.7 3.7 | -2.6 27.3 215 31 16 7.0 3.8 14000 -2.2 28.0 220 29 15 5.2 2.9 | -1.8 28.8 215 30 16 5.0 2.7 13500 -1.4 29.5 220 27 14 5.6 3.1 | -1.0 30.2 210 29 15 5.4 3.0 13000 -0.8 30.6 220 25 13 2.6 1.4 | -0.4 31.3 210 27 14 2.2 1.2 12500 -0.4 31.3 215 23 12 2.9 1.6 | -0.1 31.8 205 24 12 2.1 1.2 12000 -0.1 31.8 215 21 11 -0.3 -0.1 | 0.2 32.4 200 22 11 1.3 0.7 11500 -0.1 31.8 205 17 9 -0.8 -0.5 | 0.5 32.9 200 19 10 1.1 0.6 11000 0.1 32.2 200 16 8 4.4 2.4 | 0.9 33.6 195 17 9 3.6 2.0 10500 0.9 33.6 195 16 8 5.6 3.1 | 1.6 34.9 195 18 10 4.5 2.4 10250 1.3 34.3 195 16 8 2.9 1.6 | 1.9 35.4 195 19 10 2.8 1.5 10000 1.5 34.7 195 16 8 3.1 1.7 | 2.0 35.6 195 20 10 0.6 0.3 9750 1.9 35.4 190 18 9 5.8 3.2 | 2.1 35.8 195 20 10 0.8 0.4 9500 2.3 36.1 185 19 10 5.6 3.1 | 2.2 36.0 190 20 10 0.6 0.3 9250 2.8 37.0 180 21 11 3.8 2.1 | 2.3 36.1 185 21 11 1.3 0.7 9000 3.0 37.4 180 22 11 3.0 1.6 | 2.5 36.5 180 20 10 4.4 2.4 8750 3.4 38.1 180 23 12 5.5 3.0 | 2.9 37.2 175 20 10 7.0 3.8 8500 3.8 38.8 180 24 12 5.9 3.3 | 3.5 38.3 175 20 10 7.2 4.0 8250 4.3 39.7 180 25 13 6.3 3.5 | 4.0 39.2 170 20 10 8.9 4.9 8000 4.8 40.6 175 26 13 6.7 3.7 | 4.8 40.6 170 19 10 10.3 5.7 7750 5.3 41.5 175 27 14 7.2 3.9 | 5.5 41.9 170 19 10 9.3 5.1 7500 5.9 42.6 175 27 14 7.3 4.0 | 6.2 43.2 170 19 10 9.6 5.3 7250 6.3 43.3 170 28 14 6.7 3.7 | 7.0 44.6 170 19 10 10.6 5.8 7000 6.8 44.2 170 28 14 7.0 3.9 | 7.8 46.0 170 18 9 11.0 6.1 6750 7.3 45.1 165 28 15 5.2 2.9 | 8.6 47.5 170 18 9 8.9 4.9 6500 7.6 45.7 165 27 14 4.8 2.6 | 9.2 48.6 170 18 9 9.3 5.1 6250 8.0 46.4 165 24 12 6.4 3.5 | 10.0 50.0 170 17 9 11.3 6.2 6000 8.4 47.1 165 21 11 5.3 2.9 | 10.8 51.4 170 16 8 10.9 6.0 5750 8.9 48.0 165 18 9 8.0 4.4 | 11.6 52.9 170 15 8 10.2 5.6 5500 9.7 49.5 160 13 7 15.1 8.3 | 12.3 54.1 165 14 7 9.8 5.4 10/13/2025 at 1500 MDT | 10/13/2025 at 1800 MDT | CAPE... 0.0 LI... +9.4 | CAPE... 0.0 LI... +8.5 CINH... 0.0 K Index... +11.0 | CINH... 0.0 K Index... +11.0 | 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 -65.2 -85.4 240 83 43 2.1 1.1 | -65.1 -85.2 235 75 39 1.6 0.9 45000 -60.8 -77.4 240 107 55 6.1 3.3 | -61.2 -78.2 235 99 51 5.9 3.2 40000 -51.6 -60.9 240 117 60 4.8 2.7 | -52.3 -62.1 235 107 55 6.4 3.5 38000 -49.3 -56.7 235 95 49 3.9 2.2 | -48.3 -54.9 235 103 53 6.6 3.6 36000 -46.6 -51.9 235 71 36 4.0 2.2 | -43.9 -47.0 235 98 51 6.6 3.6 34000 -42.6 -44.7 240 59 30 8.1 4.4 | -40.6 -41.1 235 82 42 5.0 2.7 32000 -37.7 -35.9 240 52 27 8.1 4.4 | -37.6 -35.7 230 60 31 5.0 2.7 30000 -32.8 -27.0 240 52 27 8.5 4.6 | -33.3 -27.9 230 49 25 8.6 4.7 29000 -30.2 -22.4 235 54 28 8.5 4.6 | -30.7 -23.3 230 46 24 8.6 4.7 28000 -27.7 -17.9 235 55 28 8.6 4.7 | -28.2 -18.8 230 43 22 8.8 4.8 27000 -25.4 -13.7 230 56 29 7.3 4.0 | -26.0 -14.8 230 44 23 6.6 3.6 26000 -23.3 -9.9 230 56 29 7.3 4.0 | -24.0 -11.2 235 47 24 6.6 3.6 25000 -21.1 -6.0 225 57 29 7.3 4.0 | -22.1 -7.8 235 51 26 6.6 3.6 24000 -19.0 -2.2 220 57 29 6.6 3.6 | -20.0 -4.0 235 53 27 7.7 4.2 23000 -17.1 1.2 220 57 29 6.7 3.7 | -17.7 0.1 235 53 27 7.7 4.2 22000 -15.1 4.8 215 57 29 6.7 3.7 | -15.4 4.3 235 53 27 7.7 4.2 21000 -12.7 9.1 210 56 29 6.5 3.5 | -13.2 8.2 235 52 27 7.1 3.9 20000 -10.8 12.6 210 56 29 6.5 3.6 | -10.7 12.7 235 52 27 7.2 3.9 19500 -9.9 14.2 210 56 29 6.5 3.6 | -9.6 14.7 235 52 27 7.2 3.9 19000 -9.0 15.8 210 56 29 6.4 3.5 | -8.6 16.5 235 51 26 7.6 4.2 18500 -8.1 17.4 205 55 28 6.2 3.4 | -7.5 18.5 235 51 26 7.9 4.3 18000 -7.2 19.0 205 54 28 6.3 3.4 | -6.3 20.7 235 51 26 8.1 4.4 17500 -6.3 20.7 205 52 27 5.6 3.1 | -5.3 22.5 235 51 26 6.5 3.6 17000 -5.5 22.1 205 50 26 5.6 3.1 | -4.3 24.3 230 51 26 6.7 3.7 16500 -4.7 23.5 200 48 25 5.6 3.1 | -3.4 25.9 230 52 27 6.2 3.4 16000 -3.9 25.0 200 46 24 5.6 3.1 | -2.5 27.5 230 51 26 5.9 3.2 15500 -3.1 26.4 195 44 23 5.6 3.1 | -1.7 28.9 225 50 26 5.7 3.1 15000 -2.4 27.7 195 42 22 5.2 2.9 | -1.0 30.2 225 49 25 4.8 2.6 14500 -1.6 29.1 190 41 21 5.5 3.0 | -0.3 31.5 220 48 25 5.0 2.8 14000 -1.0 30.2 190 39 20 2.9 1.6 | 0.3 32.5 220 47 24 3.0 1.6 13500 -0.6 30.9 185 37 19 3.1 1.7 | 0.7 33.3 215 46 24 3.4 1.9 13000 -0.3 31.5 185 35 18 -1.1 -0.6 | 0.9 33.6 210 44 22 -1.3 -0.7 12500 -0.6 30.9 180 33 17 -2.1 -1.2 | 0.6 33.1 210 40 20 -1.8 -1.0 12000 -0.9 30.4 180 31 16 -4.8 -2.7 | 0.2 32.4 205 35 18 -4.9 -2.7 11500 -1.8 28.8 175 28 14 -6.1 -3.3 | -0.5 31.1 195 30 15 -6.0 -3.3 11000 -2.5 27.5 165 25 13 -1.2 -0.6 | -1.0 30.2 185 25 13 1.5 0.8 10500 -2.2 28.0 160 19 10 1.5 0.8 | -0.3 31.5 180 22 11 4.6 2.5 10250 -2.1 28.2 155 17 9 1.0 0.5 | 0.0 32.0 175 21 11 2.5 1.4 10000 -1.9 28.6 155 15 8 6.4 3.5 | 0.3 32.5 170 20 10 6.3 3.5 9750 -1.1 30.0 155 14 7 11.2 6.1 | 1.0 33.8 165 19 10 11.3 6.2 9500 -0.4 31.3 155 14 7 9.8 5.4 | 1.8 35.2 165 18 9 10.4 5.7 9250 0.4 32.7 155 13 7 10.5 5.8 | 2.5 36.5 160 16 8 9.3 5.1 9000 1.2 34.2 155 12 6 10.4 5.7 | 3.1 37.6 155 15 8 6.4 3.5 8750 1.9 35.4 155 12 6 9.9 5.4 | 3.5 38.3 145 14 7 5.4 3.0 8500 2.7 36.9 155 11 6 9.4 5.2 | 3.9 39.0 135 12 6 5.5 3.0 8250 3.4 38.1 155 11 5 10.7 5.9 | 4.3 39.7 125 12 6 4.2 2.3 8000 4.3 39.7 160 10 5 11.6 6.4 | 4.5 40.1 115 10 5 2.9 1.6 7750 5.1 41.2 160 10 5 9.4 5.2 | 4.8 40.6 100 10 5 3.1 1.7 7500 5.7 42.3 160 9 5 9.0 4.9 | 5.0 41.0 090 9 5 2.8 1.5 7250 6.5 43.7 160 9 5 10.7 5.9 | 5.1 41.2 080 9 4 2.3 1.3 7000 7.3 45.1 160 8 4 12.0 6.6 | 5.3 41.5 060 8 4 2.5 1.4 6750 8.1 46.6 160 8 4 7.6 4.2 | 5.4 41.7 045 8 4 1.1 0.6 6500 8.6 47.5 160 7 4 8.5 4.7 | 5.5 41.9 035 9 5 3.8 2.1 6250 10.4 50.7 165 5 3 12.5 6.9 | 5.9 42.6 025 9 5 7.5 4.1 6000 11.3 52.3 165 4 2 9.5 5.2 | 6.4 43.5 015 9 5 6.0 3.3 5750 11.8 53.2 170 4 2 4.1 2.3 | 6.9 44.4 005 10 5 8.2 4.5 5500 12.7 54.9 190 2 1 33.1 18.1 | 7.7 45.9 005 9 5 13.8 7.6 ________________________________________________________________________________ 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