Soaring Guidance
Issued by NWS Denver/Boulder, CO

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23
000
UXUS97 KBOU 030042
SRGBOU

Soaring Forecast
National Weather Service Denver/Boulder, Colorado
1842 MDT Wednesday, September 2, 2015

This forecast is for Thursday, September 3, 2015:

If the trigger temperature of 82.5 F/28.1 C is reached...then
   Thermal Soaring Index....................... Excellent
   Maximum rate of lift........................ 903 ft/min (4.6 m/s)
   Maximum height of thermals.................. 16824 ft MSL (11517 ft AGL)

Forecast maximum temperature................... 87.0 F/31.0 C
Time of trigger temperature.................... 1115 MDT
Time of overdevelopment........................ 1600 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................. 7774 ft MSL (2468 ft AGL)
Thermal soaring outlook for Friday 09/04....... 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....................... 36257 ft MSL (30950 ft AGL)
Wave soaring outlook for Friday 09/04.......... Poor

Remarks... None

Sunrise/Sunset.................... 06:29:09 / 19:29:17 MDT
Total possible sunshine........... 13 hr 0 min 8 sec (780 min 8 sec)
Altitude of sun at 12:58:46 MDT... 57.69 degrees

Upper air data from numerical model forecast valid on 09/03/2015 at 0600 MDT

Freezing level.................. 15331 ft MSL (10024 ft AGL)
Convective condensation level... 16005 ft MSL (10698 ft AGL)
Lifted condensation level....... 16227 ft MSL (10920 ft AGL)
Lifted index.................... +0.1
K index......................... +25.7

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  -64.6 -84.3   235   39   20   2.6   1.4      M     M       M      M    M
 45000  -60.6 -77.1   230   44   23   2.7   1.5      M     M       M      M    M
 40000  -55.4 -67.7   235   29   15   7.8   4.3      M     M       M      M    M
 38000  -50.7 -59.3   235   31   16   8.0   4.4      M     M       M      M    M
 36000  -45.9 -50.6   235   33   17   7.8   4.3      M     M       M      M    M
 34000  -40.4 -40.7   230   33   17   9.3   5.1      M     M       M      M    M
 32000  -34.8 -30.6   225   34   17   9.2   5.0      M     M       M      M    M
 30000  -29.8 -21.6   220   29   15   8.1   4.5   46.6 115.9    12.1      M    M
 29000  -26.8 -16.2   215   25   13   8.1   4.5   45.9 114.6    11.7      M    M
 28000  -24.5 -12.1   215   23   12   7.1   3.9   45.3 113.6    11.4      M    M
 27000  -22.4  -8.3   210   21   11   7.0   3.8   44.1 111.4    10.5      M    M
 26000  -20.4  -4.7   205   20   10   7.0   3.8   43.1 109.5     9.8      M    M
 25000  -18.3  -0.9   205   19   10   7.0   3.8   42.2 107.9     9.1      M    M
 24000  -16.3   2.7   200   17    9   6.9   3.8   41.0 105.9     8.2      M    M
 23000  -14.3   6.3   195   15    8   6.9   3.8   40.0 104.0     7.4      M    M
 22000  -12.3   9.9   185   13    7   6.7   3.7   39.1 102.3     6.6      M    M
 21000  -10.6  12.9   185   12    6   5.6   3.1   37.6  99.6     5.4      M    M
 20000   -9.0  15.8   185   11    6   5.6   3.1   36.1  97.0     4.2      M    M
 19500   -8.2  17.2   185   11    6   5.7   3.1   35.4  95.8     3.6      M    M
 19000   -7.4  18.7   185   10    5   4.8   2.6   34.7  94.4     2.9      M    M
 18500   -6.7  19.9   190    9    5   4.8   2.6   33.8  92.9     2.2      M    M
 18000   -6.0  21.2   190    9    4   5.0   2.8   33.0  91.4     1.5      M    M
 17500   -5.2  22.6   195    8    4   6.2   3.4   32.3  90.1     0.8      M    M
 17000   -4.3  24.3   200    8    4   6.0   3.3   31.7  89.0     0.3      M    M
 16500   -3.3  26.1   205    7    4   8.1   4.4   31.2  88.1    -0.2   1082  5.5
 16000   -2.1  28.2   210    7    4   8.3   4.5   30.9  87.7    -0.4   1031  5.2
 15500   -0.1  31.8   210    7    4   9.8   5.4   30.7  87.2    -0.7    951  4.8
 15000    1.3  34.3   210    7    4   9.7   5.3   30.6  87.2    -0.7    893  4.5
 14500    2.7  36.9   215    7    4   9.5   5.2   30.6  87.1    -0.7    836  4.2
 14000    4.1  39.4   215    7    4   9.4   5.2   30.6  87.0    -0.8    780  4.0
 13500    5.5  41.9   215    7    4   9.4   5.2   30.5  86.9    -0.9    724  3.7
 13000    6.8  44.2   215    7    4   9.4   5.1   30.4  86.8    -1.0    668  3.4
 12500    8.2  46.8   215    7    4   9.2   5.1   30.4  86.7    -1.1    612  3.1
 12000    9.5  49.1   220    6    3   8.8   4.8   30.3  86.5    -1.3    559  2.8
 11500   10.8  51.4   225    6    3   8.7   4.8   30.1  86.2    -1.4    505  2.6
 11000   12.0  53.6   240    5    3   8.0   4.4   29.9  85.8    -1.6    453  2.3
 10500   13.3  55.9   260    4    2   5.3   2.9   29.7  85.4    -1.9    401  2.0
 10250   13.6  56.5   265    4    2   6.1   3.3   29.2  84.6    -2.3    385  2.0
 10000   14.3  57.7   280    5    2  10.5   5.7   29.2  84.5    -2.3    356  1.8
  9750   15.0  59.0   290    5    3   9.4   5.2   29.2  84.5    -2.3    327  1.7
  9500   15.7  60.3   300    6    3   9.2   5.0   29.2  84.5    -2.3    298  1.5
  9250   16.4  61.5   310    6    3   7.7   4.2   29.1  84.3    -2.4    272  1.4
  9000   17.0  62.6   315    7    4   8.2   4.5   28.9  84.0    -2.6    247  1.3
  8750   17.6  63.7   315    8    4   8.8   4.8   28.8  83.9    -2.6    219  1.1
  8500   18.3  64.9   320    9    5   8.7   4.8   28.7  83.7    -2.7    192  1.0
  8250   18.9  66.0   320   10    5   8.9   4.9   28.7  83.6    -2.8    165  0.8
  8000   19.6  67.3   320   11    6   8.7   4.8   28.6  83.5    -2.9    139  0.7
  7750   20.2  68.4   320   13    7   8.4   4.6   28.5  83.3    -3.0    113  0.6
  7500   20.8  69.4   320   14    7   8.5   4.6   28.4  83.1    -3.1     86  0.4
  7250   21.4  70.5   320   15    8   8.6   4.7   28.3  82.9    -3.2     61  0.3
  7000   22.0  71.6   315   16    8   8.3   4.5   28.2  82.8    -3.4     36  0.2
  6750   22.6  72.7   315   17    9   8.8   4.8   28.1  82.6    -3.6     11  0.1
  6500   23.1  73.6   315   18    9   2.3   1.3   27.9  82.2    -3.8      M    M
  6250   22.8  73.0   315   16    8  -3.6  -2.0   27.0  80.6    -4.8      M    M
  6000   22.6  72.7   310   14    7  -0.6  -0.4   26.1  79.0    -5.7      M    M
  5750   22.4  72.3   305   12    6  -5.6  -3.1   25.2  77.4    -6.7      M    M
  5500   21.3  70.3   295    8    4 -20.8 -11.4   23.5  74.4    -8.5     13  0.1

 * * * * * * Numerical weather prediction model forecast data valid * * * * * *

           09/03/2015 at 0900 MDT          |       09/03/2015 at 1200 MDT
                                           |
K index... +28.0  LI... -1.6               | K index... +28.6  LI... -0.7
CAPE... +63.3  CIN... -94.8                | CAPE... +20.0  CIN... -31.6
                                           |
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 -63.6 -82.5  235  43 22   1.9   1.0 | -64.0 -83.2  235  43 22   1.0   0.5
 45000 -60.6 -77.1  230  48 25   2.4   1.3 | -61.5 -78.7  230  48 25   3.2   1.7
 40000 -55.9 -68.6  220  31 16   8.1   4.4 | -55.9 -68.6  225  38 19   8.6   4.7
 38000 -51.0 -59.8  215  32 16   8.3   4.5 | -50.6 -59.1  230  41 21   8.8   4.8
 36000 -46.0 -50.8  215  32 16   8.2   4.5 | -45.4 -49.7  230  44 23   8.8   4.8
 34000 -40.6 -41.1  215  31 16   9.2   5.1 | -40.1 -40.2  230  41 21   8.7   4.8
 32000 -35.1 -31.2  220  30 16   9.1   5.0 | -34.9 -30.8  225  36 18   8.6   4.7
 30000 -29.3 -20.7  220  29 15   8.5   4.6 | -29.2 -20.6  225  32 16   8.4   4.6
 29000 -26.8 -16.2  220  29 15   8.5   4.7 | -26.7 -16.1  225  31 16   8.4   4.6
 28000 -24.3 -11.7  220  28 14   7.3   4.0 | -24.2 -11.6  225  29 15   7.3   4.0
 27000 -22.3  -8.1  220  26 13   7.0   3.8 | -22.2  -8.0  220  27 14   7.0   3.9
 26000 -20.2  -4.4  220  24 13   7.0   3.9 | -20.1  -4.2  220  25 13   7.0   3.9
 25000 -18.1  -0.6  220  23 12   7.0   3.8 | -18.1  -0.6  215  23 12   7.0   3.9
 24000 -16.3   2.7  220  22 11   6.0   3.3 | -16.1   3.0  215  22 11   6.7   3.7
 23000 -14.6   5.7  215  21 11   6.0   3.3 | -14.1   6.6  215  22 11   6.7   3.7
 22000 -12.8   9.0  215  20 10   6.0   3.3 | -12.1  10.2  215  21 11   6.7   3.7
 21000 -11.2  11.8  215  19 10   5.8   3.2 | -10.4  13.3  210  20 10   5.9   3.2
 20000  -9.5  14.9  210  17  9   5.8   3.2 |  -8.7  16.3  205  18  9   5.9   3.2
 19500  -8.6  16.5  210  17  9   5.8   3.2 |  -7.8  18.0  205  17  9   5.9   3.2
 19000  -7.8  18.0  205  16  8   6.3   3.4 |  -7.0  19.4  205  16  8   5.6   3.1
 18500  -6.9  19.6  200  17  9   6.4   3.5 |  -6.2  20.8  200  15  8   5.6   3.1
 18000  -6.0  21.2  190  18  9   6.4   3.5 |  -5.4  22.3  200  14  7   5.6   3.1
 17500  -5.1  22.8  190  18  9   6.4   3.5 |  -4.6  23.7  190  14  7   6.0   3.3
 17000  -4.1  24.6  185  17  9   6.4   3.5 |  -3.7  25.3  185  14  7   5.9   3.3
 16500  -3.2  26.2  180  16  8   6.5   3.5 |  -2.9  26.8  175  14  7   6.7   3.7
 16000  -2.3  27.9  180  14  7   6.5   3.6 |  -1.4  29.5  165  14  7   6.9   3.8
 15500  -0.8  30.6  175  11  6   8.2   4.5 |  -0.3  31.5  155  14  7   7.6   4.2
 15000   0.4  32.7  170   9  5   8.1   4.4 |   0.8  33.4  150  13  7   7.6   4.2
 14500   1.7  35.1  165   8  4   9.6   5.3 |   1.9  35.4  140  12  6   7.9   4.3
 14000   3.2  37.8  165   6  3  10.2   5.6 |   3.1  37.6  135  10  5   8.0   4.4
 13500   4.7  40.5  165   5  3   9.6   5.3 |   4.3  39.7  125   9  4   8.0   4.4
 13000   6.1  43.0  165   4  2   8.8   4.8 |   5.5  41.9  115   7  4   8.2   4.5
 12500   7.4  45.3  170   3  1   8.6   4.7 |   6.8  44.2  100   6  3   8.2   4.5
 12000   8.6  47.5  195   1  0   7.9   4.3 |   8.0  46.4  085   5  3   8.3   4.6
 11500   9.8  49.6  340   2  1   7.9   4.3 |   9.2  48.6  070   6  3   8.4   4.6
 11000  11.1  52.0  350   4  2   8.1   4.5 |  10.6  51.1  065   6  3   9.1   5.0
 10500  12.3  54.1  355   6  3   5.4   3.0 |  11.9  53.4  065   7  4   5.5   3.0
 10250  12.6  54.7  355   7  4   6.4   3.5 |  12.2  54.0  060   7  4   6.2   3.4
 10000  13.3  55.9  360   8  4  10.8   5.9 |  12.9  55.2  060   6  3  11.4   6.3
  9750  14.0  57.2  360   9  4   9.9   5.4 |  13.6  56.5  055   6  3  10.2   5.6
  9500  14.7  58.5  005  10  5   9.4   5.1 |  14.4  57.9  045   5  3  10.0   5.5
  9250  15.3  59.5  005  10  5   7.3   4.0 |  15.1  59.2  040   5  3   8.8   4.9
  9000  15.8  60.4  005  11  5   8.0   4.4 |  15.7  60.3  040   5  2   9.7   5.3
  8750  16.5  61.7  010  11  6   9.1   5.0 |  16.5  61.7  040   5  2  10.5   5.8
  8500  17.1  62.8  010  11  6   8.9   4.9 |  17.3  63.1  035   5  2  10.3   5.7
  8250  17.8  64.0  005  11  6   9.4   5.1 |  18.1  64.6  035   5  2  10.8   5.9
  8000  18.5  65.3  005  11  6   9.2   5.1 |  18.9  66.0  035   4  2  10.3   5.7
  7750  19.2  66.6  360  11  6   9.0   4.9 |  19.6  67.3  035   4  2   9.7   5.3
  7500  19.8  67.6  355  11  6   9.1   5.0 |  20.3  68.5  035   4  2   9.9   5.4
  7250  20.5  68.9  350  12  6   9.3   5.1 |  21.1  70.0  035   4  2  10.0   5.5
  7000  21.1  70.0  345  13  6   9.1   5.0 |  21.8  71.2  030   4  2  10.0   5.5
  6750  21.8  71.2  335  13  7   9.3   5.1 |  22.5  72.5  030   4  2   9.5   5.2
  6500  22.3  72.1  330  14  7   5.2   2.9 |  23.2  73.8  030   4  2  10.2   5.6
  6250  22.5  72.5  325  12  6   2.3   1.3 |  24.1  75.4  030   4  2  11.3   6.2
  6000  22.6  72.7  325  11  5   2.2   1.2 |  24.9  76.8  030   4  2  10.1   5.6
  5750  22.7  72.9  315   8  4   3.4   1.9 |  25.7  78.3  025   4  2  12.8   7.0
  5500  23.2  73.8  305   5  3  11.5   6.3 |  26.9  80.4  025   4  2  22.6  12.4

           09/03/2015 at 1500 MDT          |       09/03/2015 at 1800 MDT
                                           |
K index... +32.0  LI... -1.1               | K index... +30.4  LI... -0.6
CAPE... +43.0  CIN... -4.2                 | CAPE... 0.0  CIN... -15.7
                                           |
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 -64.6 -84.3  235  40 21   0.3   0.2 | -64.6 -84.3  235  40 20   0.0   0.0
 45000 -62.4 -80.3  230  48 25   4.3   2.4 | -62.6 -80.7  235  43 22   4.4   2.4
 40000 -55.2 -67.4  235  43 22   8.6   4.7 | -55.1 -67.2  240  29 15   9.1   5.0
 38000 -49.9 -57.8  230  43 22   8.8   4.8 | -49.6 -57.3  235  31 16   9.2   5.0
 36000 -44.7 -48.5  225  43 22   8.7   4.8 | -44.1 -47.4  235  32 16   9.2   5.1
 34000 -39.3 -38.7  225  39 20   9.1   5.0 | -38.8 -37.8  230  33 17   8.8   4.8
 32000 -33.8 -28.8  220  35 18   8.9   4.9 | -33.6 -28.5  225  35 18   8.5   4.7
 30000 -28.3 -18.9  215  30 15   8.1   4.4 | -28.2 -18.8  220  33 17   7.9   4.3
 29000 -25.9 -14.6  210  28 14   8.1   4.4 | -25.8 -14.4  220  31 16   7.9   4.4
 28000 -23.5 -10.3  205  26 13   7.2   3.9 | -23.5 -10.3  215  30 15   7.6   4.2
 27000 -21.6  -6.9  205  24 12   6.8   3.7 | -21.3  -6.3  215  29 15   7.4   4.1
 26000 -19.6  -3.3  200  23 12   6.8   3.7 | -19.1  -2.4  210  28 15   7.4   4.1
 25000 -17.6   0.3  195  22 11   6.9   3.8 | -17.0   1.4  205  28 14   7.6   4.2
 24000 -15.8   3.6  195  21 11   5.9   3.3 | -15.0   5.0  205  27 14   6.3   3.5
 23000 -14.1   6.6  195  21 11   6.0   3.3 | -13.2   8.2  200  26 13   6.3   3.5
 22000 -12.4   9.7  195  20 10   6.0   3.3 | -11.4  11.5  200  25 13   6.4   3.5
 21000 -10.5  13.1  190  19 10   6.4   3.5 |  -9.6  14.7  195  24 12   5.9   3.2
 20000  -8.7  16.3  180  18  9   6.5   3.5 |  -7.9  17.8  185  23 12   5.9   3.2
 19500  -7.7  18.1  175  18  9   6.5   3.6 |  -7.1  19.2  185  23 12   5.9   3.2
 19000  -6.8  19.8  175  18  9   6.2   3.4 |  -6.2  20.8  180  22 12   5.9   3.2
 18500  -5.9  21.4  170  18  9   6.0   3.3 |  -5.4  22.3  175  23 12   5.8   3.2
 18000  -5.1  22.8  170  18  9   6.0   3.3 |  -4.6  23.7  175  23 12   5.8   3.2
 17500  -4.2  24.4  170  18  9   5.9   3.2 |  -3.7  25.3  170  23 12   6.0   3.3
 17000  -3.4  25.9  165  17  9   5.9   3.2 |  -2.9  26.8  170  23 12   6.0   3.3
 16500  -2.5  27.5  165  17  9   5.9   3.3 |  -2.0  28.4  170  23 12   5.8   3.2
 16000  -1.3  29.7  155  15  7   5.9   3.2 |  -0.8  30.6  170  21 11   5.7   3.1
 15500  -0.4  31.3  150  13  7   6.8   3.7 |  -0.0  32.0  170  19 10   6.1   3.3
 15000   0.6  33.1  140  11  6   7.0   3.8 |   0.9  33.6  165  17  9   6.2   3.4
 14500   1.6  34.9  125   9  5   7.9   4.3 |   1.7  35.1  165  15  8   6.1   3.4
 14000   2.9  37.2  125   8  4   8.6   4.7 |   2.6  36.7  160  13  7   6.0   3.3
 13500   4.2  39.6  120   7  4   8.9   4.9 |   3.4  38.1  160  10  5   5.9   3.3
 13000   5.5  41.9  120   6  3   9.5   5.2 |   4.2  39.6  165   7  4   5.2   2.8
 12500   7.0  44.6  120   6  3   9.5   5.2 |   5.0  41.0  175   5  3   5.1   2.8
 12000   8.4  47.1  120   5  3   9.7   5.3 |   5.9  42.6  195   3  2   7.0   3.9
 11500   9.8  49.6  125   5  3   9.7   5.3 |   6.9  44.4  235   3  1   6.9   3.8
 11000  11.2  52.2  125   5  2   8.8   4.9 |   7.8  46.0  270   4  2   6.5   3.6
 10500  12.5  54.5  125   4  2  11.1   6.1 |   8.8  47.8  290   5  3   7.7   4.2
 10250  13.5  56.3  125   4  2  12.0   6.6 |   9.4  48.9  300   6  3  10.0   5.5
 10000  14.2  57.6  125   4  2   9.8   5.4 |  10.2  50.4  300   7  4   8.9   4.9
  9750  15.0  59.0  130   4  2  10.5   5.7 |  10.8  51.4  305   8  4   7.9   4.3
  9500  15.7  60.3  130   4  2  10.2   5.6 |  11.4  52.5  305   9  5   8.0   4.4
  9250  16.5  61.7  130   3  2   8.9   4.9 |  12.0  53.6  305  10  5   8.7   4.8
  9000  17.1  62.8  130   3  2   9.3   5.1 |  12.6  54.7  305  11  6   9.5   5.2
  8750  17.9  64.2  130   3  2  10.4   5.7 |  13.3  55.9  305  11  6   9.2   5.1
  8500  18.7  65.7  135   3  1  10.1   5.6 |  14.0  57.2  305  12  6   9.3   5.1
  8250  19.4  66.9  135   3  1  11.0   6.0 |  14.7  58.5  305  13  7   9.8   5.4
  8000  20.3  68.5  140   2  1  10.4   5.7 |  15.5  59.9  305  13  7   9.8   5.4
  7750  21.0  69.8  140   2  1   9.4   5.1 |  16.2  61.2  305  14  7   9.3   5.1
  7500  21.7  71.1  140   2  1   9.7   5.3 |  16.9  62.4  305  14  7   9.7   5.3
  7250  22.4  72.3  145   2  1  10.1   5.5 |  17.6  63.7  310  14  7  10.7   5.9
  7000  23.2  73.8  145   2  1  10.1   5.5 |  18.4  65.1  310  14  7  10.7   5.9
  6750  23.9  75.0  150   2  1   9.3   5.1 |  19.2  66.6  310  15  8   9.3   5.1
  6500  24.6  76.3  155   2  1  10.0   5.5 |  19.8  67.6  310  15  8   9.6   5.2
  6250  25.4  77.7  155   2  1  11.3   6.2 |  20.6  69.1  310  15  8  10.7   5.9
  6000  26.3  79.3  160   1  1  11.0   6.0 |  21.4  70.5  310  15  7  10.3   5.7
  5750  27.1  80.8  170   1  1  11.1   6.1 |  22.2  72.0  310  14  7  11.5   6.3
  5500  28.1  82.6  180   1  1  18.0   9.9 |  23.2  73.8  310  14  7  15.9   8.7
________________________________________________________________________________

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.

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


USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.