Soaring Guidance
Issued by NWS Denver/Boulder, CO
Issued by NWS Denver/Boulder, CO
000 UXUS97 KBOU 131246 SRGBOU Soaring Forecast National Weather Service Denver/Boulder, Colorado 0646 MDT Thursday, June 13, 2013 This forecast is for Thursday, June 13, 2013: If the trigger temperature of 87.9 F/31.1 C is reached...then Thermal Soaring Index....................... Excellent Maximum rate of lift........................ 845 ft/min (4.3 m/s) Maximum height of thermals.................. 18182 ft MSL (12897 ft AGL) Forecast maximum temperature................... 94.0 F/34.9 C Time of trigger temperature.................... 1100 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................. 9675 ft MSL (4389 ft AGL) Thermal soaring outlook for Friday 06/14....... Excellent 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)................ Neither Potential height of wave....................... 14389 ft MSL (9104 ft AGL) Wave soaring outlook for Friday 06/14.......... Poor Remarks... Some stratus this am from bjc north to cys. Areas of smoke east and south of denver. Sunrise/Sunset.................... 05:31:00 / 20:28:07 MDT Total possible sunshine........... 14 hr 57 min 7 sec (897 min 7 sec) Altitude of sun at 12:59:43 MDT... 73.45 degrees Upper air data from rawinsonde observation taken on 06/13/2013 at 0600 MDT Freezing level.................. 16453 ft MSL (11168 ft AGL) Convective condensation level... 15371 ft MSL (10086 ft AGL) Lifted condensation level....... 16016 ft MSL (10730 ft AGL) Lifted index.................... -5.1 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 -65.3 -85.5 250 24 12 1.6 0.9 85.0 185.0 29.4 M M 45000 -57.6 -71.7 240 29 15 6.7 3.7 72.2 161.9 23.6 M M 40000 -58.7 -73.7 240 50 26 8.3 4.5 47.8 118.0 8.9 M M 38000 -53.7 -64.7 235 49 25 8.3 4.6 46.6 115.8 8.3 M M 36000 -48.1 -54.6 220 44 22 10.0 5.5 46.1 115.0 8.2 M M 34000 -42.7 -44.9 220 43 22 8.9 4.9 45.6 114.0 8.0 M M 32000 -37.5 -35.5 220 42 22 8.7 4.8 44.6 112.3 7.5 M M 30000 -32.1 -25.8 235 33 17 7.7 4.2 43.1 109.5 6.5 M M 29000 -29.9 -21.8 235 32 16 7.6 4.2 42.2 108.0 5.9 M M 28000 -27.6 -17.7 235 31 16 7.6 4.2 41.4 106.5 5.3 M M 27000 -25.3 -13.5 235 30 15 8.6 4.7 40.7 105.2 4.8 M M 26000 -22.7 -8.9 235 29 15 9.1 5.0 40.2 104.4 4.6 M M 25000 -19.7 -3.5 235 28 14 9.6 5.3 40.3 104.5 4.7 M M 24000 -16.9 1.6 240 30 16 9.2 5.1 40.1 104.1 4.5 M M 23000 -14.2 6.4 240 33 17 9.2 5.1 40.0 103.9 4.5 M M 22000 -11.9 10.6 250 23 12 6.2 3.4 39.1 102.5 3.8 M M 21000 -10.1 13.8 270 13 7 6.1 3.3 37.9 100.2 2.8 M M 20000 -8.4 16.9 255 17 9 6.1 3.4 36.6 97.9 1.7 M M 19500 -7.5 18.5 250 19 10 6.3 3.4 36.0 96.7 1.1 M M 19000 -6.7 19.9 250 22 12 6.3 3.5 35.2 95.3 0.4 M M 18500 -5.5 22.1 255 23 12 8.5 4.6 34.9 94.9 0.2 M M 18000 -4.2 24.4 255 24 12 8.6 4.7 34.7 94.5 -0.0 1234 6.3 17500 -2.9 26.8 260 25 13 8.6 4.7 34.5 94.1 -0.2 1181 6.0 17000 -1.7 28.9 265 25 13 8.6 4.7 34.3 93.8 -0.4 1129 5.7 16500 -0.4 31.3 265 26 13 8.6 4.7 34.2 93.6 -0.6 1076 5.5 16000 0.9 33.6 270 27 14 8.6 4.7 34.1 93.3 -0.7 1023 5.2 15500 2.2 36.0 270 27 14 8.6 4.7 33.9 93.0 -0.9 970 4.9 15000 4.1 39.4 275 26 14 8.6 4.7 33.6 92.5 -1.2 891 4.5 14500 5.3 41.5 275 27 14 8.6 4.7 33.4 92.1 -1.4 838 4.3 14000 6.6 43.9 275 28 14 8.7 4.7 33.2 91.7 -1.6 785 4.0 13500 7.9 46.2 270 28 14 8.6 4.7 33.0 91.3 -1.9 732 3.7 13000 9.2 48.6 270 28 14 9.4 5.2 32.8 91.1 -2.1 678 3.4 12500 10.5 50.9 265 26 13 9.4 5.1 32.8 91.0 -2.1 622 3.2 12000 11.9 53.4 265 24 12 9.4 5.1 32.7 90.9 -2.2 566 2.9 11500 13.3 55.9 265 24 12 9.4 5.2 32.6 90.7 -2.4 510 2.6 11000 14.7 58.5 265 23 12 9.4 5.1 32.6 90.6 -2.5 454 2.3 10500 16.1 61.0 265 23 12 9.0 5.0 32.5 90.5 -2.5 398 2.0 10250 16.7 62.1 265 23 12 8.3 4.6 32.4 90.3 -2.7 372 1.9 10000 17.3 63.1 260 23 12 8.5 4.7 32.3 90.1 -2.8 347 1.8 9750 17.8 64.0 260 23 12 8.1 4.4 32.2 89.9 -3.0 322 1.6 9500 18.4 65.1 260 23 12 9.8 5.4 32.1 89.8 -3.1 297 1.5 9250 19.0 66.2 255 23 12 3.5 1.9 32.0 89.6 -3.3 272 1.4 9000 18.7 65.7 255 23 12 -7.8 -4.3 31.0 87.8 -4.3 274 1.4 8750 18.0 64.4 260 20 10 -6.6 -3.6 29.6 85.3 -5.8 288 1.5 8500 17.3 63.1 265 17 9 -15.3 -8.4 28.2 82.8 -7.2 303 1.5 8250 15.7 60.3 275 15 8 -18.3 -10.0 25.9 78.6 -9.6 343 1.7 8000 14.7 58.5 285 13 7 -4.9 -2.7 24.3 75.7 -11.3 364 1.9 7750 14.5 58.1 285 12 6 3.0 1.6 23.5 74.2 -12.2 363 1.8 7500 14.7 58.5 285 11 6 1.3 0.7 23.0 73.4 -12.8 350 1.8 7250 14.0 57.2 290 11 6 -18.4 -10.1 21.7 71.1 -14.3 364 1.8 7000 12.1 53.8 290 10 5 -19.5 -10.7 19.2 66.6 -16.9 412 2.1 6750 11.5 52.7 295 9 5 -5.1 -2.8 17.7 63.8 -18.3 425 2.2 6500 11.3 52.3 300 8 4 -1.7 -0.9 16.7 62.0 -19.3 422 2.1 6250 11.5 52.7 310 7 4 6.1 3.3 16.0 60.9 -19.9 411 2.1 6000 12.1 53.8 320 6 3 10.8 5.9 16.0 60.9 -20.0 383 1.9 5750 12.8 55.0 330 5 3 9.2 5.1 16.0 60.9 -20.1 355 1.8 5500 13.5 56.3 350 4 2 10.8 5.9 16.0 60.9 -20.2 327 1.7 * * * * * * Numerical weather prediction model forecast data valid * * * * * * 06/13/2013 at 0900 MDT | 06/13/2013 at 1200 MDT | K index... +14.1 LI... +1.2 | K index... +15.5 LI... -1.3 CAPE... 0.0 CIN... -18.2 | CAPE... +456.4 CIN... -207.4 | 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 -63.1 -81.6 240 25 13 2.8 1.6 | -62.6 -80.7 230 28 14 2.7 1.5 45000 -59.2 -74.6 240 31 16 1.4 0.8 | -58.9 -74.0 235 37 19 1.4 0.8 40000 -56.3 -69.3 230 44 23 7.3 4.0 | -56.0 -68.8 230 47 24 7.1 3.9 38000 -51.8 -61.2 230 43 22 7.4 4.1 | -51.7 -61.1 230 47 24 7.2 3.9 36000 -47.4 -53.3 230 41 21 7.3 4.0 | -47.4 -53.3 230 46 24 7.2 3.9 34000 -42.5 -44.5 225 38 20 8.2 4.5 | -43.2 -45.8 230 43 22 7.0 3.9 32000 -37.6 -35.7 225 35 18 8.0 4.4 | -39.0 -38.2 230 40 21 6.9 3.8 30000 -32.7 -26.9 235 31 16 7.2 3.9 | -33.4 -28.1 230 36 19 8.6 4.7 29000 -30.5 -22.9 240 30 15 7.2 3.9 | -30.8 -23.4 230 35 18 8.6 4.7 28000 -28.3 -18.9 240 29 15 8.2 4.5 | -28.2 -18.8 230 33 17 7.9 4.3 27000 -25.8 -14.4 240 27 14 8.3 4.5 | -25.9 -14.6 230 33 17 7.9 4.3 26000 -23.3 -9.9 240 26 13 8.3 4.5 | -23.5 -10.3 230 34 17 7.9 4.3 25000 -20.8 -5.4 240 25 13 7.7 4.2 | -21.2 -6.2 230 34 17 8.1 4.5 24000 -18.8 -1.8 240 26 13 6.6 3.6 | -18.6 -1.5 230 34 17 8.5 4.7 23000 -16.8 1.8 240 28 14 6.7 3.7 | -16.1 3.0 235 33 17 8.5 4.7 22000 -14.9 5.2 240 29 15 7.6 4.2 | -13.5 7.7 235 33 17 7.5 4.1 21000 -12.4 9.7 240 29 15 8.5 4.7 | -11.6 11.1 240 34 17 6.8 3.7 20000 -10.0 14.0 240 29 15 8.7 4.8 | -9.6 14.7 240 35 18 7.0 3.8 19500 -8.7 16.3 240 29 15 8.8 4.8 | -8.7 16.3 245 36 18 7.2 3.9 19000 -7.4 18.7 240 30 15 8.8 4.8 | -7.5 18.5 245 35 18 8.5 4.6 18500 -6.1 21.0 240 30 16 8.8 4.8 | -6.3 20.7 245 34 18 8.4 4.6 18000 -4.8 23.4 245 30 16 8.9 4.9 | -5.1 22.8 245 33 17 8.8 4.8 17500 -3.5 25.7 245 30 15 9.0 4.9 | -3.7 25.3 245 32 17 9.1 5.0 17000 -2.1 28.2 245 29 15 9.0 4.9 | -2.4 27.7 245 32 16 9.1 5.0 16500 -0.8 30.6 245 28 14 9.1 5.0 | -1.1 30.0 245 30 16 8.7 4.8 16000 0.6 33.1 250 27 14 9.2 5.0 | 0.2 32.4 245 29 15 8.7 4.8 15500 2.6 36.7 250 26 14 8.6 4.7 | 1.6 34.9 245 28 14 9.6 5.2 15000 3.8 38.8 250 26 13 8.5 4.7 | 3.7 38.7 240 27 14 9.8 5.4 14500 5.2 41.4 250 25 13 9.4 5.2 | 5.1 41.2 240 26 13 8.9 4.9 14000 6.6 43.9 255 23 12 9.4 5.1 | 6.5 43.7 235 25 13 9.0 4.9 13500 8.0 46.4 255 22 11 9.3 5.1 | 7.8 46.0 235 25 13 9.3 5.1 13000 9.4 48.9 255 21 11 9.2 5.1 | 9.2 48.6 235 24 12 9.4 5.2 12500 10.8 51.4 260 19 10 9.2 5.1 | 10.6 51.1 235 23 12 9.3 5.1 12000 12.2 54.0 255 17 9 9.2 5.1 | 12.0 53.6 235 22 11 9.3 5.1 11500 13.6 56.5 255 16 8 9.1 5.0 | 13.4 56.1 235 21 11 9.2 5.0 11000 14.9 58.8 255 15 8 8.6 4.7 | 14.7 58.5 230 19 10 8.7 4.8 10500 16.2 61.2 250 13 7 4.1 2.3 | 16.1 61.0 230 18 9 4.0 2.2 10250 16.3 61.3 250 13 7 3.1 1.7 | 16.2 61.2 230 18 9 5.6 3.1 10000 16.8 62.2 245 13 7 8.6 4.7 | 17.1 62.8 230 17 9 12.8 7.0 9750 17.4 63.3 245 12 6 8.3 4.5 | 17.9 64.2 225 17 9 11.6 6.3 9500 18.0 64.4 245 12 6 5.2 2.9 | 18.8 65.8 225 16 8 9.3 5.1 9250 18.1 64.6 245 12 6 1.3 0.7 | 19.3 66.7 225 16 8 7.0 3.8 9000 18.2 64.8 245 11 6 0.5 0.3 | 19.9 67.8 225 15 8 8.7 4.8 8750 18.1 64.6 245 11 6 -0.3 -0.2 | 20.6 69.1 220 15 8 10.3 5.7 8500 18.1 64.6 245 11 5 -1.8 -1.0 | 21.3 70.3 220 14 7 5.5 3.0 8250 17.8 64.0 245 10 5 -3.4 -1.9 | 21.5 70.7 215 13 7 2.2 1.2 8000 17.5 63.5 250 9 5 -3.2 -1.8 | 21.6 70.9 210 11 6 -0.6 -0.4 7750 17.2 63.0 250 8 4 -4.1 -2.3 | 21.3 70.3 200 10 5 -5.3 -2.9 7500 16.7 62.1 255 7 4 -6.0 -3.3 | 20.9 69.6 185 9 4 -1.8 -1.0 7250 16.1 61.0 250 7 3 -6.8 -3.7 | 20.7 69.3 170 7 4 -0.0 -0.0 7000 15.6 60.1 250 6 3 -7.3 -4.0 | 20.5 68.9 145 6 3 0.5 0.3 6750 15.0 59.0 245 6 3 -3.6 -2.0 | 20.5 68.9 130 6 3 5.4 3.0 6500 14.9 58.8 245 5 2 2.0 1.1 | 21.1 70.0 125 5 3 10.4 5.7 6250 15.0 59.0 235 3 2 1.8 1.0 | 21.9 71.4 120 5 3 11.9 6.5 6000 15.0 59.0 220 2 1 3.8 2.1 | 22.7 72.9 120 5 3 9.5 5.2 5750 15.5 59.9 205 2 1 11.9 6.5 | 23.5 74.3 120 5 2 15.2 8.3 5500 16.7 62.1 195 2 1 18.9 10.3 | 25.2 77.4 115 5 2 30.5 16.7 06/13/2013 at 1500 MDT | 06/13/2013 at 1800 MDT | K index... +26.6 LI... -3.3 | K index... +21.0 LI... -3.0 CAPE... +976.9 CIN... -7.0 | CAPE... +984.8 CIN... -29.9 | 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 -62.9 -81.2 230 29 15 2.6 1.4 | -63.1 -81.6 230 31 16 2.9 1.6 45000 -59.1 -74.4 235 40 21 2.0 1.1 | -59.3 -74.7 235 42 21 1.7 0.9 40000 -55.6 -68.1 235 47 24 6.4 3.5 | -55.8 -68.4 235 49 25 6.8 3.7 38000 -51.7 -61.1 235 47 24 6.4 3.5 | -51.7 -61.1 235 46 24 6.8 3.8 36000 -47.9 -54.2 235 47 24 6.3 3.5 | -47.6 -53.7 230 43 22 6.7 3.7 34000 -43.2 -45.8 235 46 24 8.2 4.5 | -42.9 -45.2 230 43 22 8.1 4.5 32000 -38.3 -36.9 230 45 23 8.1 4.4 | -38.0 -36.4 230 42 22 8.0 4.4 30000 -32.7 -26.9 230 45 23 8.2 4.5 | -33.2 -27.8 230 42 22 8.0 4.4 29000 -30.3 -22.5 230 45 23 8.2 4.5 | -30.3 -22.5 235 42 21 8.0 4.4 28000 -27.9 -18.2 235 44 23 7.8 4.3 | -27.9 -18.2 235 41 21 7.8 4.3 27000 -25.5 -13.9 235 44 23 7.8 4.3 | -25.6 -14.1 240 41 21 7.8 4.3 26000 -23.2 -9.8 240 44 23 7.8 4.3 | -23.3 -9.9 245 40 21 7.8 4.3 25000 -20.9 -5.6 240 44 22 7.7 4.2 | -21.0 -5.8 250 40 21 7.7 4.2 24000 -18.7 -1.7 240 41 21 7.4 4.0 | -18.8 -1.8 250 37 19 7.4 4.1 23000 -16.6 2.1 245 39 20 7.4 4.1 | -16.6 2.1 245 34 18 7.4 4.1 22000 -14.4 6.1 245 37 19 7.4 4.1 | -14.4 6.1 245 31 16 7.7 4.2 21000 -12.2 10.0 245 34 18 7.4 4.1 | -12.1 10.2 240 28 14 8.0 4.4 20000 -10.1 13.8 240 32 16 7.4 4.1 | -9.8 14.4 235 25 13 8.0 4.4 19500 -9.0 15.8 240 31 16 7.4 4.1 | -8.6 16.5 235 24 12 8.0 4.4 19000 -7.8 18.0 235 30 15 8.4 4.6 | -7.4 18.7 230 24 12 9.4 5.1 18500 -6.6 20.1 235 28 15 8.3 4.6 | -6.0 21.2 230 23 12 9.2 5.1 18000 -5.4 22.3 230 27 14 8.6 4.7 | -4.6 23.7 225 23 12 9.2 5.1 17500 -4.1 24.6 225 26 14 8.8 4.8 | -3.3 26.1 225 23 12 9.2 5.1 17000 -2.8 27.0 225 25 13 8.8 4.8 | -1.9 28.6 225 23 12 9.2 5.1 16500 -1.4 29.5 220 25 13 10.3 5.6 | -0.5 31.1 225 23 12 9.4 5.2 16000 0.1 32.2 220 24 12 10.1 5.6 | 0.9 33.6 220 23 12 9.4 5.2 15500 1.6 34.9 215 24 12 10.2 5.6 | 2.3 36.1 220 22 12 9.6 5.3 15000 3.9 39.0 215 23 12 10.2 5.6 | 3.8 38.8 220 22 11 9.7 5.3 14500 5.4 41.7 210 23 12 10.0 5.5 | 5.9 42.6 220 22 11 9.4 5.2 14000 6.8 44.2 210 22 11 10.0 5.5 | 7.3 45.1 220 21 11 9.4 5.2 13500 8.3 46.9 205 21 11 9.7 5.3 | 8.8 47.8 220 21 11 9.7 5.3 13000 9.7 49.5 200 20 10 9.6 5.3 | 10.2 50.4 220 21 11 9.8 5.4 12500 11.1 52.0 195 19 10 9.6 5.3 | 11.7 53.1 215 20 10 9.5 5.2 12000 12.5 54.5 190 18 9 9.6 5.3 | 13.0 55.4 215 20 10 9.3 5.1 11500 13.9 57.0 180 17 9 9.4 5.2 | 14.4 57.9 215 19 10 9.3 5.1 11000 15.3 59.5 175 15 8 9.0 5.0 | 15.8 60.4 210 18 9 9.2 5.1 10500 16.6 61.9 170 14 7 6.4 3.5 | 17.2 63.0 210 18 9 6.4 3.5 10250 17.0 62.6 170 14 7 7.4 4.0 | 17.6 63.7 210 17 9 7.1 3.9 10000 17.8 64.0 170 14 7 11.6 6.4 | 18.3 64.9 205 17 9 11.3 6.2 9750 18.6 65.5 165 13 7 11.0 6.1 | 19.1 66.4 205 17 9 10.4 5.7 9500 19.4 66.9 165 13 7 9.1 5.0 | 19.9 67.8 205 16 8 9.6 5.3 9250 19.9 67.8 165 12 6 8.1 4.5 | 20.5 68.9 200 16 8 8.6 4.7 9000 20.6 69.1 160 12 6 10.3 5.6 | 21.1 70.0 200 15 8 9.3 5.1 8750 21.4 70.5 160 12 6 10.2 5.6 | 21.8 71.2 200 15 8 9.3 5.1 8500 22.1 71.8 160 11 6 10.2 5.6 | 22.5 72.5 200 14 7 9.4 5.2 8250 22.9 73.2 160 11 6 10.2 5.6 | 23.2 73.8 195 13 7 9.7 5.3 8000 23.6 74.5 160 11 6 9.8 5.4 | 23.9 75.0 195 13 6 8.9 4.9 7750 24.3 75.7 155 11 5 9.3 5.1 | 24.5 76.1 195 12 6 8.2 4.5 7500 25.1 77.2 155 10 5 10.1 5.6 | 25.1 77.2 195 11 6 8.8 4.8 7250 25.8 78.4 155 10 5 10.9 6.0 | 25.7 78.3 195 10 5 9.4 5.2 7000 26.6 79.9 155 10 5 10.4 5.7 | 26.4 79.5 195 8 4 8.9 4.9 6750 27.4 81.3 150 9 5 10.0 5.5 | 27.0 80.6 195 7 4 7.9 4.4 6500 28.1 82.6 150 9 5 10.5 5.7 | 27.6 81.7 195 6 3 9.0 4.9 6250 28.9 84.0 150 9 5 11.3 6.2 | 28.2 82.8 195 4 2 10.0 5.5 6000 29.7 85.5 150 8 4 9.6 5.2 | 28.9 84.0 200 3 2 9.4 5.2 5750 30.5 86.9 150 8 4 13.0 7.2 | 29.6 85.3 200 2 1 8.9 4.9 5500 31.9 89.4 145 7 4 26.0 14.2 | 30.1 86.2 210 1 1 9.6 5.3 ________________________________________________________________________________ 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. 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
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