Soaring Guidance
Issued by NWS Denver/Boulder, CO
Issued by NWS Denver/Boulder, CO
438 UXUS97 KBOU 030111 SRGBOU Soaring Forecast National Weather Service Denver/Boulder, Colorado 1910 MDT Thursday, May 2, 2024 This forecast is for Friday, May 3, 2024: If the trigger temperature of 62.3 F/16.8 C is reached...then Thermal Soaring Index....................... Excellent Maximum rate of lift........................ 1012 ft/min (5.1 m/s) Maximum height of thermals.................. 16193 ft MSL (10906 ft AGL) Forecast maximum temperature................... 68.0 F/20.5 C Time of trigger temperature.................... 1030 MDT Time of overdevelopment........................ 1500 MDT Middle/high clouds during soaring window....... None Surface winds during soaring window............ 20 mph or less Height of the -3 thermal index................. 9354 ft MSL (4066 ft AGL) Thermal soaring outlook for Saturday 05/04..... Good Wave Soaring Index............................. Good Wave Soaring Index trend (to 1800 MDT)......... Little change Height of stable layer (12-18K ft MSL)......... None Weak PVA/NVA (through 1800 MDT)................ Weak PVA Potential height of wave....................... 19051 ft MSL (13764 ft AGL) Wave soaring outlook for Saturday 05/04........ Fair Remarks... Sunrise/Sunset.................... 05:56:27 / 19:56:07 MDT Total possible sunshine........... 13 hr 59 min 40 sec (839 min 40 sec) Altitude of sun at 12:56:17 MDT... 66.21 degrees Upper air data from numerical model forecast valid on 05/03/2024 at 0600 MDT Freezing level.................. 11376 ft MSL (6089 ft AGL) Convective condensation level... 15331 ft MSL (10044 ft AGL) Lifted condensation level....... 15583 ft MSL (10295 ft AGL) Lifted index.................... -0.4 K index......................... +14.8 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 -53.1 -63.6 250 39 20 0.6 0.3 M M M M M 45000 -52.3 -62.1 250 52 27 0.6 0.3 M M M M M 40000 -57.8 -72.0 255 66 34 -3.6 -2.0 M M M M M 38000 -57.7 -71.9 255 70 36 4.0 2.2 M M M M M 36000 -55.2 -67.4 255 73 38 4.0 2.2 M M M M M 34000 -52.6 -62.7 255 76 39 6.9 3.8 M M M M M 32000 -48.7 -55.7 255 72 37 6.6 3.6 M M M M M 30000 -44.6 -48.3 255 69 35 7.6 4.2 31.5 88.8 8.7 M M 29000 -41.8 -43.2 255 66 34 7.5 4.1 30.3 86.5 7.9 M M 28000 -39.6 -39.3 255 63 32 7.5 4.1 29.5 85.1 7.3 M M 27000 -37.3 -35.1 255 61 31 7.6 4.2 28.8 83.8 6.8 M M 26000 -35.0 -31.0 255 57 29 7.6 4.2 27.8 82.1 6.2 M M 25000 -32.8 -27.0 255 53 27 7.6 4.2 27.0 80.6 5.6 M M 24000 -30.5 -22.9 260 49 25 7.5 4.1 26.3 79.4 5.1 M M 23000 -28.3 -18.9 260 45 23 7.3 4.0 25.3 77.6 4.3 M M 22000 -26.2 -15.2 260 41 21 7.3 4.0 24.4 76.0 3.6 M M 21000 -24.0 -11.2 260 38 20 7.8 4.3 23.7 74.6 3.0 M M 20000 -21.6 -6.9 260 40 20 8.0 4.4 23.0 73.3 2.4 M M 19500 -20.4 -4.7 260 40 21 8.0 4.4 22.6 72.8 2.1 M M 19000 -19.3 -2.7 260 41 21 7.9 4.3 22.4 72.3 1.9 M M 18500 -18.1 -0.6 260 42 22 7.5 4.1 22.1 71.8 1.7 M M 18000 -17.1 1.2 260 41 21 7.0 3.8 21.6 70.9 1.2 M M 17500 -16.0 3.2 260 40 21 6.9 3.8 21.1 70.0 0.8 M M 17000 -14.9 5.2 260 40 20 8.3 4.6 20.8 69.4 0.5 M M 16500 -13.7 7.3 260 39 20 8.2 4.5 20.5 68.9 0.2 M M 16000 -12.5 9.5 260 39 20 8.5 4.7 20.3 68.5 -0.0 1002 5.1 15500 -11.2 11.8 260 38 19 8.6 4.7 20.1 68.1 -0.3 950 4.8 15000 -10.0 14.0 260 37 19 8.7 4.8 19.9 67.8 -0.4 897 4.6 14500 -8.0 17.6 255 34 18 8.8 4.9 19.6 67.3 -0.7 816 4.1 14000 -6.7 19.9 255 32 17 8.8 4.8 19.5 67.1 -0.8 762 3.9 13500 -5.4 22.3 250 30 16 8.7 4.8 19.3 66.8 -1.0 708 3.6 13000 -4.1 24.6 250 28 14 8.8 4.8 19.2 66.5 -1.1 654 3.3 12500 -2.7 27.1 245 26 14 8.9 4.9 19.0 66.2 -1.3 599 3.0 12000 -1.4 29.5 240 25 13 8.6 4.7 18.9 66.0 -1.4 544 2.8 11500 -0.1 31.8 235 23 12 8.2 4.5 18.6 65.5 -1.6 492 2.5 11000 1.1 34.0 230 21 11 7.4 4.0 18.4 65.1 -1.8 440 2.2 10500 2.1 35.8 225 20 10 6.0 3.3 17.9 64.2 -2.3 396 2.0 10250 2.6 36.7 225 20 10 8.9 4.9 17.7 63.8 -2.6 374 1.9 10000 3.3 37.9 225 19 10 9.4 5.1 17.7 63.9 -2.5 343 1.7 9750 3.9 39.0 220 18 9 6.8 3.7 17.5 63.5 -2.7 319 1.6 9500 4.4 39.9 220 18 9 7.4 4.1 17.3 63.2 -2.9 296 1.5 9250 5.0 41.0 220 17 9 7.4 4.1 17.1 62.8 -3.1 272 1.4 9000 5.5 41.9 215 17 9 7.5 4.1 17.0 62.5 -3.3 248 1.3 8750 6.1 43.0 215 17 9 7.1 3.9 16.8 62.2 -3.5 225 1.1 8500 6.6 43.9 215 16 8 6.9 3.8 16.6 61.8 -3.7 202 1.0 8250 7.1 44.8 215 16 8 7.4 4.1 16.3 61.4 -4.0 179 0.9 8000 7.6 45.7 215 17 9 7.7 4.2 16.2 61.2 -4.1 156 0.8 7750 8.1 46.6 210 19 10 5.4 3.0 16.0 60.7 -4.4 134 0.7 7500 8.4 47.1 205 21 11 4.7 2.6 15.6 60.0 -4.9 118 0.6 7250 8.7 47.7 205 23 12 3.2 1.8 15.2 59.3 -5.3 101 0.5 7000 8.8 47.8 200 26 13 1.1 0.6 14.5 58.2 -6.0 92 0.5 6750 8.8 47.8 195 28 15 1.9 1.1 13.9 57.1 -6.6 82 0.4 6500 8.9 48.0 190 31 16 0.4 0.2 13.3 55.9 -7.3 73 0.4 6250 8.8 47.8 185 31 16 -4.3 -2.4 12.4 54.4 -8.2 70 0.4 6000 8.3 46.9 185 28 14 -5.4 -3.0 11.3 52.3 -9.4 76 0.4 5750 7.9 46.2 180 25 13 -7.8 -4.3 10.1 50.2 -10.6 82 0.4 5500 7.0 44.6 175 19 10 -14.2 -7.8 8.5 47.3 -12.3 101 0.5 * * * * * * Numerical weather prediction model forecast data valid * * * * * * 05/03/2024 at 0900 MDT | 05/03/2024 at 1200 MDT | CAPE... 0.0 LI... +2.3 | CAPE... +4.7 LI... +0.9 CINH... 0.0 K Index... +9.2 | CINH... -9.8 K Index... +14.3 | 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 -54.5 -66.1 255 27 14 -0.4 -0.2 | -55.9 -68.6 255 27 14 -1.0 -0.5 45000 -55.2 -67.4 260 41 21 -1.6 -0.9 | -57.4 -71.3 260 48 25 -1.7 -0.9 40000 -58.7 -73.7 265 67 34 -2.3 -1.3 | -60.4 -76.7 260 65 33 -2.0 -1.1 38000 -58.3 -72.9 265 71 36 3.6 2.0 | -59.2 -74.6 260 67 34 5.5 3.0 36000 -56.2 -69.2 265 68 35 3.6 2.0 | -55.9 -68.6 260 65 33 5.6 3.0 34000 -53.6 -64.5 265 66 34 8.3 4.5 | -52.3 -62.1 260 63 32 7.7 4.2 32000 -48.9 -56.0 260 63 33 7.9 4.3 | -47.7 -53.9 255 61 32 7.6 4.2 30000 -43.4 -46.1 260 61 31 8.4 4.6 | -42.4 -44.3 250 59 31 8.3 4.6 29000 -40.9 -41.6 260 59 30 8.5 4.6 | -39.9 -39.8 250 58 30 8.3 4.6 28000 -38.4 -37.1 260 57 29 8.5 4.6 | -37.4 -35.3 255 57 29 8.3 4.6 27000 -35.9 -32.6 260 56 29 8.1 4.4 | -34.9 -30.8 255 56 29 8.2 4.5 26000 -33.5 -28.3 255 54 28 8.0 4.4 | -32.5 -26.5 250 56 29 8.1 4.5 25000 -31.1 -24.0 255 53 27 8.0 4.4 | -30.1 -22.2 250 56 29 8.1 4.5 24000 -28.7 -19.7 255 52 27 7.6 4.2 | -27.6 -17.7 250 56 29 7.9 4.4 23000 -26.6 -15.9 250 49 25 7.0 3.9 | -25.3 -13.5 250 55 28 7.7 4.2 22000 -24.5 -12.1 250 45 23 7.1 3.9 | -23.0 -9.4 250 55 28 7.7 4.2 21000 -22.4 -8.3 250 42 22 6.8 3.7 | -20.8 -5.4 250 54 28 5.5 3.0 20000 -20.4 -4.7 250 41 21 6.7 3.7 | -19.3 -2.7 250 52 27 5.1 2.8 19500 -19.4 -2.9 250 40 21 6.7 3.7 | -18.6 -1.5 250 51 26 5.1 2.8 19000 -18.4 -1.1 250 39 20 6.8 3.7 | -17.8 -0.0 250 49 25 5.1 2.8 18500 -17.4 0.7 250 39 20 7.2 4.0 | -17.1 1.2 250 48 25 5.2 2.9 18000 -16.3 2.7 250 38 20 7.6 4.1 | -16.4 2.5 250 45 23 5.3 2.9 17500 -15.1 4.8 250 38 20 7.6 4.2 | -15.6 3.9 255 42 22 5.2 2.9 17000 -14.0 6.8 255 38 20 7.2 4.0 | -14.6 5.7 250 39 20 8.3 4.6 16500 -13.0 8.6 255 38 19 7.2 4.0 | -13.4 7.9 250 35 18 8.0 4.4 16000 -11.9 10.6 255 37 19 7.4 4.1 | -12.2 10.0 250 32 16 9.0 4.9 15500 -10.8 12.6 255 36 18 7.5 4.1 | -10.8 12.6 250 30 15 9.2 5.1 15000 -9.7 14.5 255 34 18 7.7 4.2 | -8.8 16.2 250 27 14 9.3 5.1 14500 -7.9 17.8 255 30 16 8.0 4.4 | -7.4 18.7 245 26 13 9.3 5.1 14000 -6.7 19.9 255 28 14 8.8 4.8 | -6.0 21.2 245 24 13 9.4 5.1 13500 -5.4 22.3 255 26 13 8.9 4.9 | -4.6 23.7 245 23 12 9.4 5.1 13000 -4.0 24.8 255 24 12 9.3 5.1 | -3.2 26.2 240 22 11 9.2 5.0 12500 -2.6 27.3 255 24 12 9.6 5.2 | -1.8 28.8 240 21 11 9.0 4.9 12000 -1.2 29.8 255 24 12 9.6 5.2 | -0.5 31.1 235 20 10 8.8 4.9 11500 0.3 32.5 255 25 13 9.5 5.2 | 0.8 33.4 230 18 9 8.7 4.8 11000 1.7 35.1 260 27 14 8.7 4.8 | 2.1 35.8 225 17 9 8.3 4.5 10500 2.9 37.2 255 25 13 7.2 3.9 | 3.3 37.9 220 16 8 7.4 4.1 10250 3.5 38.3 255 24 13 11.1 6.1 | 3.9 39.0 215 15 8 9.8 5.4 10000 4.5 40.1 255 24 12 11.9 6.5 | 4.7 40.5 210 15 8 10.8 5.9 9750 5.1 41.2 255 24 12 8.4 4.6 | 5.4 41.7 210 14 7 9.1 5.0 9500 5.8 42.4 255 24 12 9.4 5.1 | 6.1 43.0 205 14 7 9.6 5.3 9250 6.5 43.7 255 24 12 9.1 5.0 | 6.8 44.2 205 13 7 9.5 5.2 9000 7.2 45.0 255 23 12 8.8 4.8 | 7.6 45.7 200 13 7 9.8 5.4 8750 7.8 46.0 255 22 12 8.5 4.7 | 8.3 46.9 200 12 6 9.9 5.4 8500 8.5 47.3 255 22 11 8.5 4.7 | 9.0 48.2 200 12 6 9.9 5.4 8250 9.1 48.4 255 22 11 8.8 4.8 | 9.8 49.6 200 12 6 9.9 5.4 8000 9.8 49.6 255 22 11 9.1 5.0 | 10.5 50.9 200 12 6 9.9 5.5 7750 10.5 50.9 250 22 11 8.1 4.4 | 11.3 52.3 200 12 6 10.0 5.5 7500 11.1 52.0 250 22 11 8.7 4.8 | 12.0 53.6 200 12 6 10.0 5.5 7250 11.7 53.1 245 22 11 5.0 2.7 | 12.8 55.0 200 11 6 10.2 5.6 7000 11.8 53.2 240 23 12 0.9 0.5 | 13.5 56.3 200 11 6 10.3 5.7 6750 11.8 53.2 235 23 12 -2.5 -1.4 | 14.3 57.7 200 11 6 9.6 5.3 6500 11.4 52.5 230 22 11 -4.6 -2.5 | 15.0 59.0 200 11 6 9.4 5.2 6250 11.2 52.2 225 20 10 0.8 0.4 | 15.7 60.3 200 11 5 10.8 5.9 6000 11.3 52.3 215 17 9 2.8 1.5 | 16.6 61.9 200 10 5 11.9 6.5 5750 11.4 52.5 205 15 8 3.5 1.9 | 17.4 63.3 200 10 5 10.3 5.6 5500 11.9 53.4 200 12 6 12.5 6.8 | 18.3 64.9 200 9 5 14.7 8.1 05/03/2024 at 1500 MDT | 05/03/2024 at 1800 MDT | CAPE... +24.2 LI... -0.1 | CAPE... +145.6 LI... +0.1 CINH... -26.3 K Index... +15.4 | CINH... -79.1 K Index... +19.6 | 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 -55.0 -67.0 255 32 17 -0.7 -0.4 | -55.1 -67.2 250 31 16 0.0 0.0 45000 -56.1 -69.0 260 55 28 -1.7 -0.9 | -55.1 -67.2 260 49 25 -1.6 -0.9 40000 -59.3 -74.7 260 63 32 -2.1 -1.2 | -58.6 -73.5 255 62 32 -2.3 -1.3 38000 -58.3 -72.9 260 64 33 5.0 2.7 | -57.5 -71.5 255 65 33 4.6 2.5 36000 -55.3 -67.5 255 62 32 5.0 2.7 | -54.8 -66.6 255 64 33 4.6 2.5 34000 -52.0 -61.6 255 61 31 7.5 4.1 | -51.6 -60.9 255 63 33 7.1 3.9 32000 -47.0 -52.6 250 60 31 7.4 4.1 | -47.3 -53.1 255 61 32 7.2 3.9 30000 -42.3 -44.1 250 59 30 8.3 4.6 | -42.9 -45.2 250 60 31 7.9 4.3 29000 -39.8 -39.6 250 58 30 8.3 4.6 | -40.5 -40.9 250 59 30 7.9 4.4 28000 -37.3 -35.1 250 58 30 8.3 4.6 | -38.1 -36.6 250 58 30 7.9 4.4 27000 -34.9 -30.8 250 57 30 7.6 4.2 | -35.8 -32.4 250 57 29 7.3 4.0 26000 -32.6 -26.7 250 57 30 7.5 4.1 | -33.7 -28.7 245 52 27 6.9 3.8 25000 -30.4 -22.7 250 57 30 7.5 4.1 | -31.7 -25.1 240 47 24 6.9 3.8 24000 -28.2 -18.8 250 57 30 6.6 3.6 | -29.6 -21.3 230 44 23 6.9 3.8 23000 -26.5 -15.7 250 54 28 5.7 3.1 | -27.1 -16.8 235 40 21 7.0 3.8 22000 -24.8 -12.6 250 51 26 5.7 3.2 | -25.0 -13.0 240 38 19 7.1 3.9 21000 -23.0 -9.4 250 47 24 8.0 4.4 | -22.7 -8.9 245 35 18 9.4 5.2 20000 -20.5 -4.9 245 40 21 8.3 4.6 | -20.0 -4.0 240 31 16 9.2 5.1 19500 -19.3 -2.7 245 37 19 8.3 4.6 | -18.7 -1.7 235 30 15 9.3 5.1 19000 -18.1 -0.6 245 34 17 8.4 4.6 | -17.3 0.9 230 28 14 9.5 5.2 18500 -16.9 1.6 240 31 16 8.0 4.4 | -16.1 3.0 230 27 14 7.1 3.9 18000 -15.8 3.6 240 30 15 7.8 4.3 | -15.0 5.0 230 25 13 7.2 3.9 17500 -14.6 5.7 240 29 15 7.9 4.3 | -14.0 6.8 230 24 12 7.6 4.2 17000 -13.3 8.1 240 28 14 9.6 5.3 | -12.8 9.0 230 23 12 8.2 4.5 16500 -11.9 10.6 240 27 14 9.5 5.2 | -11.5 11.3 235 22 11 8.2 4.5 16000 -10.4 13.3 240 26 14 9.5 5.2 | -10.2 13.6 235 20 10 9.1 5.0 15500 -8.3 17.1 240 25 13 9.6 5.2 | -8.9 16.0 235 19 10 9.0 4.9 15000 -6.9 19.6 235 24 12 9.3 5.1 | -7.5 18.5 235 17 9 9.0 5.0 14500 -5.5 22.1 235 23 12 9.3 5.1 | -6.2 20.8 240 15 8 9.0 5.0 14000 -4.1 24.6 235 21 11 9.2 5.1 | -4.8 23.4 240 14 7 9.1 5.0 13500 -2.7 27.1 235 20 10 9.2 5.1 | -3.5 25.7 245 12 6 9.1 5.0 13000 -1.3 29.7 230 18 9 8.9 4.9 | -2.1 28.2 245 10 5 9.0 4.9 12500 -0.0 32.0 230 17 9 8.8 4.8 | -0.8 30.6 250 8 4 8.9 4.9 12000 1.3 34.3 230 15 8 8.9 4.9 | 0.5 32.9 260 7 3 8.8 4.8 11500 2.6 36.7 230 13 7 8.9 4.9 | 1.8 35.2 275 6 3 8.3 4.6 11000 4.0 39.2 230 11 6 8.5 4.6 | 3.0 37.4 295 6 3 8.1 4.5 10500 5.2 41.4 230 10 5 7.3 4.0 | 4.1 39.4 315 6 3 7.3 4.0 10250 5.8 42.4 235 9 5 11.4 6.2 | 4.7 40.5 320 6 3 6.0 3.3 10000 6.8 44.2 235 9 4 12.2 6.7 | 5.2 41.4 330 7 4 11.3 6.2 9750 7.5 45.5 235 8 4 8.7 4.8 | 6.2 43.2 340 8 4 12.4 6.8 9500 8.2 46.8 235 8 4 9.7 5.3 | 7.5 45.5 350 11 5 9.7 5.3 9250 8.9 48.0 235 7 4 9.2 5.1 | 8.2 46.8 355 12 6 6.0 3.3 9000 9.6 49.3 240 7 4 9.6 5.2 | 8.5 47.3 355 13 7 6.8 3.7 8750 10.3 50.5 240 7 4 9.9 5.4 | 9.3 48.7 360 14 7 10.5 5.7 8500 11.1 52.0 240 7 3 9.7 5.3 | 10.0 50.0 005 16 8 10.0 5.5 8250 11.8 53.2 240 6 3 10.2 5.6 | 10.7 51.3 005 17 9 8.3 4.5 8000 12.6 54.7 245 6 3 10.5 5.7 | 11.2 52.2 010 19 10 6.9 3.8 7750 13.3 55.9 245 6 3 9.9 5.4 | 11.8 53.2 015 20 10 8.6 4.7 7500 14.1 57.4 245 6 3 9.7 5.3 | 12.5 54.5 015 22 11 8.7 4.8 7250 14.8 58.6 250 6 3 9.9 5.4 | 13.1 55.6 020 23 12 8.1 4.4 7000 15.5 59.9 250 5 3 10.0 5.5 | 13.7 56.7 020 24 12 7.8 4.3 6750 16.3 61.3 250 5 3 9.6 5.3 | 14.3 57.7 020 25 13 9.8 5.4 6500 17.0 62.6 255 5 3 9.4 5.2 | 15.1 59.2 025 25 13 9.5 5.2 6250 17.7 63.9 255 5 3 9.8 5.4 | 15.7 60.3 025 25 13 7.4 4.0 6000 18.5 65.3 260 5 2 10.1 5.6 | 16.2 61.2 025 23 12 7.4 4.1 5750 19.2 66.6 260 5 2 10.0 5.5 | 16.7 62.1 025 22 11 7.9 4.4 5500 20.0 68.0 265 4 2 12.0 6.6 | 17.1 62.8 030 18 9 6.8 3.7 ________________________________________________________________________________ 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