Soaring Guidance
Issued by NWS Grand Junction, CO
Issued by NWS Grand Junction, CO
622 UXUS97 KGJT 251307 SRGGJT Soaring Forecast National Weather Service Grand Junction, Colorado 707 AM MDT Saturday, May 25, 2024 This forecast is for Saturday, May 25, 2024: If the trigger temperature of 70.3 F/21.3 C is reached...then Thermal Soaring Index....................... Good Maximum rate of lift........................ 565 ft/min (2.9 m/s) Maximum height of thermals.................. 15322 ft MSL (10483 ft AGL) Forecast maximum temperature................... 75.0 F/24.3 C Time of trigger temperature.................... 1100 MDT Time of overdevelopment........................ None 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................. 8265 ft MSL (3426 ft AGL) Thermal soaring outlook for Sunday 05/26....... Good Wave Soaring Index............................. Not available Remarks... Sunrise/Sunset.................... 05:53:00 / 20:29:21 MDT Total possible sunshine........... 14 hr 36 min 20 sec (876 min 20 sec) Altitude of sun at 13:11:10 MDT... 71.86 degrees Upper air data from rawinsonde observation taken on 05/25/2024 at 0600 MDT Freezing level.................. 12318 ft MSL (7479 ft AGL) Convective condensation level... 16240 ft MSL (11401 ft AGL) Lifted condensation level....... 16043 ft MSL (11204 ft AGL) Lifted index.................... -0.5 K index......................... +17.9 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 -55.5 -67.9 255 63 32 -2.1 -1.1 106.0 222.8 47.2 M M 45000 -51.6 -60.9 245 75 39 2.5 1.4 87.8 190.1 39.2 M M 40000 -51.6 -60.9 245 90 46 -8.1 -4.4 64.9 148.8 26.9 M M 38000 -53.4 -64.1 240 104 54 -2.6 -1.4 52.3 126.1 19.2 M M 36000 -52.4 -62.3 235 98 50 -1.7 -0.9 45.1 113.3 14.7 M M 34000 -50.9 -59.6 240 89 46 5.6 3.1 39.0 102.1 10.7 M M 32000 -47.2 -53.0 235 76 39 8.9 4.9 36.0 96.8 8.9 M M 30000 -41.9 -43.4 240 77 40 9.0 4.9 35.2 95.4 8.5 M M 29000 -39.3 -38.7 240 78 40 9.0 4.9 34.8 94.6 8.2 M M 28000 -36.9 -34.4 235 75 39 5.5 3.0 34.1 93.4 7.8 M M 27000 -35.1 -31.2 230 70 36 7.7 4.2 32.6 90.7 6.8 M M 26000 -32.6 -26.7 230 66 34 8.3 4.5 32.1 89.7 6.4 M M 25000 -30.1 -22.2 235 60 31 7.9 4.3 31.5 88.8 6.1 M M 24000 -28.2 -18.8 235 61 31 7.6 4.2 30.2 86.3 5.1 M M 23000 -25.6 -14.1 240 56 29 8.7 4.8 29.8 85.6 4.8 M M 22000 -23.0 -9.4 240 56 29 8.6 4.7 29.4 84.9 4.6 M M 21000 -21.1 -6.0 235 51 26 6.1 3.3 28.2 82.8 3.6 M M 20000 -18.8 -1.8 225 42 22 5.7 3.1 26.7 80.1 2.3 M M 19500 -17.6 0.3 225 44 22 9.1 5.0 26.4 79.5 2.0 M M 19000 -16.6 2.1 220 41 21 7.2 4.0 25.9 78.7 1.6 M M 18500 -15.3 4.5 215 43 22 9.1 5.0 25.7 78.2 1.4 M M 18000 -14.0 6.8 220 41 21 9.4 5.2 25.5 78.0 1.3 M M 17500 -12.5 9.5 215 43 22 10.0 5.5 25.6 78.0 1.3 M M 17000 -11.2 11.8 210 42 22 8.2 4.5 25.5 77.9 1.2 M M 16500 -10.0 14.0 210 39 20 7.9 4.3 25.2 77.3 0.9 M M 16000 -8.9 16.0 215 35 18 7.2 4.0 24.8 76.6 0.5 M M 15500 -7.8 18.0 220 34 17 7.5 4.1 24.4 75.9 0.1 M M 15000 -6.9 19.6 230 30 15 6.0 3.3 23.9 75.0 -0.4 932 4.7 14500 -5.8 21.6 235 33 17 8.9 4.9 23.5 74.3 -0.7 884 4.5 14000 -4.4 24.1 240 31 16 8.9 4.9 23.4 74.1 -0.9 830 4.2 13500 -3.1 26.4 235 31 16 8.9 4.9 23.3 73.9 -1.0 775 3.9 13000 -1.8 28.8 235 29 15 8.9 4.9 23.1 73.6 -1.1 720 3.7 12500 -0.4 31.3 240 29 15 8.9 4.9 23.0 73.4 -1.2 665 3.4 12000 0.9 33.6 235 32 17 8.9 4.9 22.9 73.2 -1.4 611 3.1 11500 2.2 36.0 230 31 16 8.9 4.9 22.7 72.9 -1.5 556 2.8 11000 3.6 38.5 225 32 16 8.9 4.9 22.6 72.6 -1.7 501 2.5 10500 4.9 40.8 230 24 12 8.9 4.9 22.4 72.3 -1.9 446 2.3 10250 5.5 41.9 220 24 12 9.0 4.9 22.3 72.2 -1.9 419 2.1 10000 6.2 43.2 220 24 12 8.8 4.8 22.3 72.1 -2.0 392 2.0 9750 6.9 44.4 225 22 11 8.5 4.7 22.2 71.9 -2.1 365 1.9 9500 7.5 45.5 220 20 10 8.5 4.7 22.1 71.7 -2.2 339 1.7 9250 8.1 46.6 215 18 9 8.5 4.7 22.0 71.5 -2.3 312 1.6 9000 8.8 47.8 210 16 8 8.6 4.7 21.9 71.4 -2.4 286 1.5 8750 9.4 48.9 205 14 7 8.1 4.4 21.8 71.2 -2.5 259 1.3 8500 9.9 49.8 200 12 6 7.3 4.0 21.6 70.9 -2.7 235 1.2 8250 10.4 50.7 195 10 5 6.9 3.8 21.4 70.5 -3.0 213 1.1 8000 11.0 51.8 185 10 5 7.9 4.3 21.2 70.1 -3.2 190 1.0 7750 11.4 52.5 180 9 5 0.4 0.2 20.9 69.6 -3.5 171 0.9 7500 11.0 51.8 165 8 4 -5.7 -3.1 19.8 67.6 -4.6 173 0.9 7250 10.9 51.6 145 7 4 3.1 1.7 18.9 66.0 -5.5 169 0.9 7000 11.4 52.5 125 8 4 7.7 4.2 18.6 65.5 -5.7 147 0.7 6750 11.9 53.4 115 5 3 6.4 3.5 18.4 65.1 -6.0 125 0.6 6500 12.4 54.3 090 3 2 6.8 3.7 18.2 64.7 -6.3 103 0.5 6250 12.9 55.2 045 3 1 6.6 3.6 17.9 64.3 -6.5 82 0.4 6000 13.3 55.9 355 4 2 7.2 4.0 17.7 63.9 -6.8 60 0.3 5750 13.8 56.8 335 4 2 4.0 2.2 17.4 63.4 -7.1 38 0.2 5500 13.9 57.0 290 3 1 1.4 0.8 16.8 62.3 -7.7 27 0.1 5250 14.2 57.6 330 3 2 5.2 2.9 16.3 61.4 -8.2 12 0.1 5000 14.5 58.1 305 4 2 0.4 0.2 15.9 60.7 -8.6 M M * * * * * * Numerical weather prediction model forecast data valid * * * * * * 05/25/2024 at 0900 MDT | 05/25/2024 at 1200 MDT | CAPE... +11.1 LI... +0.2 | CAPE... +262.0 LI... -1.8 CINH... -22.5 K Index... +23.3 | CINH... -6.6 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 -52.9 -63.2 250 58 30 1.9 1.1 | -52.7 -62.9 250 60 31 1.9 1.0 45000 -50.2 -58.4 250 72 37 0.3 0.2 | -50.0 -58.0 250 67 35 -0.0 -0.0 40000 -49.5 -57.1 240 79 41 0.4 0.2 | -49.7 -57.5 245 71 36 0.2 0.1 38000 -49.5 -57.1 240 77 40 -0.3 -0.1 | -49.8 -57.6 245 69 36 -0.5 -0.3 36000 -49.7 -57.5 240 72 37 -0.3 -0.1 | -50.1 -58.2 250 67 34 -0.5 -0.3 34000 -49.4 -56.9 235 67 34 3.6 2.0 | -49.7 -57.5 250 63 32 6.1 3.4 32000 -47.3 -53.1 235 59 31 3.4 1.9 | -46.2 -51.2 250 53 27 5.9 3.2 30000 -44.8 -48.6 235 53 27 8.0 4.4 | -42.6 -44.7 250 43 22 6.0 3.3 29000 -42.4 -44.3 235 51 26 7.9 4.3 | -40.8 -41.4 250 39 20 6.0 3.3 28000 -40.0 -40.0 235 49 25 7.9 4.3 | -39.0 -38.2 250 34 18 6.0 3.3 27000 -37.7 -35.9 235 48 24 8.0 4.4 | -37.2 -35.0 250 30 15 6.3 3.5 26000 -35.3 -31.5 235 48 25 8.2 4.5 | -35.0 -31.0 250 30 16 7.5 4.1 25000 -32.8 -27.0 235 48 25 8.2 4.5 | -32.8 -27.0 250 31 16 7.5 4.1 24000 -30.4 -22.7 235 49 25 8.2 4.5 | -30.0 -22.0 250 33 17 7.5 4.1 23000 -27.4 -17.3 235 48 25 8.2 4.5 | -27.8 -18.0 245 34 17 7.4 4.1 22000 -24.9 -12.8 240 47 24 8.2 4.5 | -25.6 -14.1 245 35 18 7.4 4.1 21000 -22.5 -8.5 240 45 23 7.6 4.2 | -23.4 -10.1 245 36 19 7.9 4.3 20000 -20.3 -4.5 235 43 22 7.6 4.2 | -21.0 -5.8 240 37 19 7.9 4.4 19500 -19.1 -2.4 235 42 22 7.6 4.2 | -19.8 -3.6 240 37 19 8.0 4.4 19000 -18.0 -0.4 235 41 21 7.6 4.2 | -18.7 -1.7 240 37 19 8.0 4.4 18500 -16.9 1.6 235 40 21 7.5 4.1 | -17.5 0.5 240 37 19 8.1 4.4 18000 -15.8 3.6 235 39 20 7.5 4.1 | -16.3 2.7 235 37 19 8.1 4.5 17500 -14.7 5.5 230 37 19 7.6 4.1 | -15.1 4.8 235 37 19 8.1 4.5 17000 -13.5 7.7 230 36 19 7.8 4.3 | -13.9 7.0 235 36 19 8.1 4.5 16500 -12.4 9.7 230 35 18 7.8 4.3 | -12.7 9.1 235 35 18 8.1 4.5 16000 -11.3 11.7 230 33 17 7.3 4.0 | -11.5 11.3 235 35 18 8.1 4.4 15500 -10.2 13.6 230 33 17 7.3 4.0 | -10.3 13.5 230 34 17 8.1 4.4 15000 -9.2 15.4 230 32 16 7.4 4.1 | -9.1 15.6 230 32 17 8.3 4.6 14500 -8.1 17.4 230 31 16 7.6 4.1 | -7.9 17.8 230 31 16 8.5 4.7 14000 -7.0 19.4 230 30 16 7.9 4.3 | -6.6 20.1 230 30 15 8.6 4.7 13500 -5.8 21.6 230 29 15 8.6 4.7 | -5.4 22.3 230 29 15 8.8 4.8 13000 -4.5 23.9 230 29 15 8.7 4.8 | -4.1 24.6 230 27 14 8.8 4.8 12500 -3.1 26.4 230 28 14 9.2 5.0 | -2.7 27.1 230 26 13 9.0 4.9 12000 -1.8 28.8 230 27 14 9.2 5.0 | -1.4 29.5 230 25 13 9.0 4.9 11500 -0.4 31.3 230 26 13 9.1 5.0 | -0.1 31.8 230 23 12 9.0 5.0 11000 0.9 33.6 230 25 13 8.9 4.9 | 1.2 34.2 235 22 11 8.9 4.9 10500 2.1 35.8 235 23 12 6.6 3.6 | 2.4 36.3 235 21 11 6.4 3.5 10250 2.6 36.7 235 22 12 8.9 4.9 | 2.9 37.2 235 20 10 9.0 5.0 10000 3.4 38.1 235 22 11 11.4 6.3 | 3.7 38.7 235 19 10 11.7 6.4 9750 4.2 39.6 235 21 11 8.9 4.9 | 4.5 40.1 240 19 10 9.5 5.2 9500 4.8 40.6 235 19 10 7.3 4.0 | 5.2 41.4 240 18 9 8.2 4.5 9250 5.4 41.7 235 18 9 7.6 4.2 | 5.8 42.4 245 17 9 8.6 4.7 9000 5.9 42.6 235 17 9 9.1 5.0 | 6.5 43.7 245 16 8 10.6 5.8 8750 6.7 44.1 230 16 8 8.9 4.9 | 8.0 46.4 245 16 8 9.2 5.0 8500 7.2 45.0 235 14 7 7.0 3.9 | 8.7 47.7 250 15 8 9.9 5.4 8250 8.3 46.9 235 11 6 5.8 3.2 | 9.4 48.9 250 15 8 8.6 4.7 8000 8.7 47.7 230 10 5 6.2 3.4 | 10.1 50.2 255 14 7 9.1 5.0 7750 9.3 48.7 230 9 5 8.7 4.8 | 10.8 51.4 255 14 7 10.5 5.8 7500 9.9 49.8 230 8 4 8.0 4.4 | 11.6 52.9 255 14 7 10.2 5.6 7250 10.4 50.7 230 7 4 4.6 2.5 | 12.3 54.1 255 13 7 7.6 4.2 7000 10.7 51.3 220 7 3 7.0 3.8 | 12.8 55.0 260 13 7 8.9 4.9 6750 11.5 52.7 220 6 3 11.5 6.3 | 13.7 56.7 260 13 7 12.2 6.7 6500 12.3 54.1 225 5 3 9.7 5.3 | 14.5 58.1 260 12 6 10.8 6.0 6250 13.0 55.4 220 5 3 9.2 5.0 | 15.3 59.5 260 12 6 11.0 6.0 6000 13.6 56.5 215 5 3 8.5 4.6 | 16.1 61.0 265 12 6 8.3 4.6 5750 14.3 57.7 220 4 2 13.0 7.1 | 16.8 62.2 265 11 6 14.4 7.9 5500 16.2 61.2 215 4 2 42.9 23.5 | 19.7 67.5 270 11 5 81.4 44.6 5250 M M M M M M M | M M M M M M M 5000 M M M M M M M | M M M M M M M 05/25/2024 at 1500 MDT | 05/25/2024 at 1800 MDT | CAPE... +283.1 LI... -1.7 | CAPE... +314.9 LI... -1.3 CINH... -1.4 K Index... +25.3 | CINH... -20.7 K Index... +26.3 | 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 -52.4 -62.3 250 58 30 1.6 0.9 | -52.5 -62.5 250 56 29 1.1 0.6 45000 -50.2 -58.4 255 64 33 0.4 0.2 | -50.8 -59.4 260 62 32 1.4 0.7 40000 -49.3 -56.7 250 65 34 0.6 0.3 | -48.7 -55.7 260 61 31 1.4 0.8 38000 -49.7 -57.5 250 65 33 -1.5 -0.8 | -49.1 -56.4 260 58 30 -2.0 -1.1 36000 -50.6 -59.1 250 65 33 -1.5 -0.8 | -50.3 -58.5 260 55 28 -2.0 -1.1 34000 -50.8 -59.4 250 63 32 5.0 2.8 | -50.8 -59.4 255 50 26 4.9 2.7 32000 -48.0 -54.4 250 55 28 4.8 2.6 | -48.0 -54.4 250 42 22 4.6 2.5 30000 -44.6 -48.3 250 47 24 8.6 4.7 | -44.7 -48.5 245 36 18 8.8 4.8 29000 -42.1 -43.8 255 45 23 8.5 4.7 | -42.1 -43.8 245 34 18 8.7 4.8 28000 -39.5 -39.1 255 42 22 8.5 4.7 | -39.5 -39.1 245 33 17 8.7 4.8 27000 -37.0 -34.6 255 40 21 8.5 4.7 | -36.9 -34.4 245 32 16 8.7 4.8 26000 -34.4 -29.9 255 39 20 8.4 4.6 | -34.3 -29.7 245 31 16 8.5 4.7 25000 -31.3 -24.3 255 37 19 8.4 4.6 | -31.2 -24.2 245 30 16 8.5 4.7 24000 -28.8 -19.8 255 36 18 7.6 4.2 | -28.6 -19.5 245 30 15 8.3 4.5 23000 -26.7 -16.1 255 34 17 7.2 3.9 | -26.2 -15.2 240 29 15 8.1 4.5 22000 -24.5 -12.1 250 32 16 7.2 4.0 | -23.8 -10.8 240 29 15 8.1 4.5 21000 -22.4 -8.3 245 30 16 7.8 4.3 | -21.4 -6.5 240 29 15 7.7 4.2 20000 -20.1 -4.2 240 30 15 7.8 4.3 | -19.1 -2.4 235 30 15 7.7 4.2 19500 -18.9 -2.0 240 30 15 7.9 4.3 | -18.0 -0.4 235 31 16 7.7 4.2 19000 -17.8 -0.0 235 30 15 7.9 4.3 | -16.9 1.6 235 31 16 7.7 4.2 18500 -16.6 2.1 235 30 15 8.3 4.6 | -15.7 3.7 235 31 16 7.7 4.2 18000 -15.3 4.5 235 30 15 8.5 4.6 | -14.6 5.7 235 32 16 7.7 4.2 17500 -14.1 6.6 235 30 15 8.5 4.7 | -13.5 7.7 235 32 17 7.7 4.2 17000 -12.8 9.0 230 30 15 8.6 4.7 | -12.4 9.7 235 32 17 7.5 4.1 16500 -11.6 11.1 230 29 15 8.6 4.7 | -11.2 11.8 235 33 17 7.6 4.2 16000 -10.3 13.5 230 29 15 8.7 4.8 | -10.1 13.8 235 33 17 7.4 4.1 15500 -9.0 15.8 230 28 14 8.7 4.8 | -9.1 15.6 235 33 17 7.4 4.1 15000 -7.7 18.1 230 27 14 8.9 4.9 | -8.0 17.6 235 33 17 7.5 4.1 14500 -6.4 20.5 230 27 14 8.9 4.9 | -6.9 19.6 235 32 17 7.5 4.1 14000 -5.1 22.8 230 26 13 9.0 4.9 | -5.8 21.6 240 32 17 7.6 4.1 13500 -3.7 25.3 230 25 13 9.1 5.0 | -4.7 23.5 240 32 16 7.7 4.2 13000 -2.4 27.7 230 25 13 9.1 5.0 | -3.5 25.7 240 32 16 7.7 4.2 12500 -1.0 30.2 235 24 12 9.2 5.0 | -2.4 27.7 245 31 16 7.9 4.3 12000 0.4 32.7 235 23 12 9.2 5.1 | -1.2 29.8 245 30 16 7.9 4.3 11500 1.8 35.2 235 22 12 9.6 5.3 | -0.0 32.0 250 30 15 8.6 4.7 11000 3.2 37.8 235 22 11 9.5 5.2 | 1.2 34.2 250 29 15 8.5 4.7 10500 4.5 40.1 235 21 11 7.0 3.8 | 2.4 36.3 255 29 15 6.8 3.7 10250 5.0 41.0 240 20 10 9.7 5.3 | 2.9 37.2 255 29 15 8.4 4.6 10000 5.9 42.6 240 20 10 12.1 6.7 | 3.6 38.5 255 28 15 10.4 5.7 9750 6.7 44.1 240 20 10 10.2 5.6 | 4.4 39.9 255 28 14 9.1 5.0 9500 7.5 45.5 240 20 10 9.5 5.2 | 5.0 41.0 260 28 14 8.2 4.5 9250 8.2 46.8 240 19 10 9.8 5.4 | 5.6 42.1 260 28 14 8.4 4.6 9000 8.9 48.0 240 19 10 10.2 5.6 | 6.8 44.2 265 27 14 8.1 4.5 8750 10.4 50.7 240 19 10 9.8 5.4 | 7.4 45.3 265 26 13 8.1 4.5 8500 11.2 52.2 245 18 9 9.9 5.4 | 8.0 46.4 265 25 13 8.0 4.4 8250 11.9 53.4 245 18 9 9.9 5.4 | 8.6 47.5 265 25 13 8.4 4.6 8000 12.7 54.9 245 18 9 10.1 5.5 | 9.2 48.6 270 25 13 9.0 4.9 7750 13.4 56.1 245 18 9 10.0 5.5 | 9.9 49.8 270 24 12 9.1 5.0 7500 14.2 57.6 245 17 9 10.5 5.7 | 10.5 50.9 270 23 12 9.1 5.0 7250 14.9 58.8 245 17 9 8.6 4.7 | 11.2 52.2 275 22 11 7.8 4.3 7000 15.5 59.9 250 17 9 9.1 5.0 | 11.7 53.1 275 23 12 8.9 4.9 6750 16.3 61.3 250 16 8 11.2 6.1 | 12.5 54.5 275 21 11 10.9 6.0 6500 17.1 62.8 250 15 8 10.9 6.0 | 13.3 55.9 275 20 10 10.2 5.6 6250 17.9 64.2 250 15 8 11.0 6.0 | 14.1 57.4 275 19 10 10.6 5.8 6000 18.9 66.0 250 15 8 17.4 9.5 | 14.8 58.6 280 19 10 8.6 4.7 5750 20.6 69.1 250 14 7 29.0 15.9 | 15.4 59.7 275 17 9 9.2 5.1 5500 22.4 72.3 255 13 6 8.1 4.4 | 16.9 62.4 280 14 7 41.2 22.6 5250 M M M M M M M | M M M M M M M 5000 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) 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 at Walker Field in Grand Junction, Colorado at North Latitude: 39 deg 07 min 00.001 sec West Longitude: 108 deg 31 min 59.998 sec Elevation: 4839 feet (1475 meters) and may not be representative of other areas along the Western Slope of Colorado. 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