Soaring Guidance
Issued by NWS Pueblo, CO

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7
000
UXUS97 KPUB 221304
SRGPUB

Soaring Forecast
National Weather Service Pueblo, Colorado
0703 MDT Sunday, October 22, 2017

This forecast is for Sunday, October 22, 2017:

If the trigger temperature of 53.0 F/11.7 C is reached...then
   Thermal Soaring Index....................... Good
   Maximum rate of lift........................ 767 ft/min (3.9 m/s)
   Maximum height of thermals.................. 16966 ft MSL (9336 ft AGL)

Forecast maximum temperature................... 67.0 F/19.9 C
Time of trigger temperature.................... 1045 MDT
Time of overdevelopment........................ None
Middle/high clouds during soaring window....... None
Surface winds during soaring window............ 20 mph or less
Height of the -3 thermal index................. 14864 ft MSL (7234 ft AGL)
Thermal soaring outlook for Monday 10/23....... Good

Wave Soaring Index............................. Not available

Remarks... For tomorrow, dry adiabatic lapse rate from the surface to about 5
           kft agl, then strong inversion at about 5 kft agl

Sunrise/Sunset.................... 07:16:28 / 18:10:51 MDT
Total possible sunshine........... 10 hr 54 min 23 sec (654 min 23 sec)
Altitude of sun at 12:43:39 MDT... 39.57 degrees

Upper air data from numerical model forecast valid on 10/22/2017 at 0600 MDT

Freezing level.................. 7742 ft MSL (112 ft AGL)
Additional freezing level....... 11475 ft MSL (3845 ft AGL)
Convective condensation level... 21196 ft MSL (13566 ft AGL)
Lifted condensation level....... 19414 ft MSL (11784 ft AGL)
Lifted index.................... +3.9
K index......................... +0.9

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  -61.0 -77.8   315   23   12   0.7   0.4      M     M       M      M    M
 45000  -60.1 -76.2   315   29   15   0.0   0.0      M     M       M      M    M
 40000  -60.1 -76.2   310   23   12  -0.4  -0.2      M     M       M      M    M
 38000  -56.0 -68.8   325   29   15   7.3   4.0      M     M       M      M    M
 36000  -51.6 -60.9   335   38   19   7.3   4.0      M     M       M      M    M
 34000  -47.0 -52.6   340   40   21   8.0   4.4      M     M       M      M    M
 32000  -42.2 -44.0   335   38   20   8.0   4.4      M     M       M      M    M
 30000  -37.4 -35.3   335   35   18   8.0   4.4   31.5  88.6     9.3      M    M
 29000  -35.0 -31.0   330   34   17   8.0   4.4   30.8  87.4     8.9      M    M
 28000  -32.6 -26.7   330   33   17   8.0   4.4   30.2  86.4     8.5      M    M
 27000  -30.2 -22.4   330   32   16   8.3   4.5   29.6  85.3     8.1      M    M
 26000  -27.7 -17.9   330   32   16   8.3   4.6   29.0  84.2     7.7      M    M
 25000  -25.2 -13.4   330   31   16   8.3   4.6   28.5  83.4     7.4      M    M
 24000  -22.9  -9.2   325   31   16   7.2   4.0   28.0  82.3     7.0      M    M
 23000  -20.7  -5.3   325   30   16   7.4   4.0   27.0  80.6     6.3      M    M
 22000  -17.9  -0.2   325   29   15   7.4   4.1   26.0  78.9     5.5      M    M
 21000  -16.0   3.2   325   28   14   6.1   3.4   24.9  76.8     4.5      M    M
 20000  -14.2   6.4   325   26   13   6.1   3.4   23.6  74.5     3.5      M    M
 19500  -13.3   8.1   320   25   13   6.1   3.3   23.0  73.5     3.0      M    M
 19000  -12.4   9.7   320   24   12   5.8   3.2   22.5  72.4     2.5      M    M
 18500  -11.5  11.3   320   22   11   5.4   3.0   21.7  71.1     1.8      M    M
 18000  -10.7  12.7   320   19   10   5.3   2.9   21.0  69.8     1.2      M    M
 17500   -9.9  14.2   320   18    9   6.1   3.3   20.3  68.6     0.6      M    M
 17000   -9.0  15.8   320   16    8   6.0   3.3   19.7  67.5     0.0      M    M
 16500   -8.1  17.4   320   15    8   5.4   3.0   19.1  66.4    -0.6    726  3.7
 16000   -7.4  18.7   325   14    7   5.0   2.8   18.3  64.9    -1.3    690  3.5
 15500   -6.6  20.1   325   13    7   5.0   2.7   17.5  63.5    -2.0    653  3.3
 15000   -5.9  21.4   325   12    6   4.9   2.7   16.7  62.1    -2.8    616  3.1
 14500   -5.2  22.6   325   11    6   5.0   2.7   15.9  60.7    -3.5    580  2.9
 14000   -4.5  23.9   325   10    5   4.0   2.2   15.1  59.2    -4.4    545  2.8
 13500   -3.9  25.0   325    8    4   4.0   2.2   14.2  57.6    -5.2    512  2.6
 13000   -3.3  26.1   325    7    4   5.3   2.9   13.4  56.1    -6.1    478  2.4
 12500   -2.5  27.5   325    6    3   5.3   2.9   12.7  54.8    -6.8    439  2.2
 12000   -1.5  29.3   330    7    3   8.3   4.6   12.2  53.9    -7.3    396  2.0
 11750   -0.9  30.4   335    7    4   9.0   5.0   12.1  53.8    -7.4    369  1.9
 11500   -0.2  31.6   340    8    4   8.2   4.5   12.0  53.7    -7.5    342  1.7
 11250    0.3  32.5   345    8    4   6.6   3.6   11.8  53.3    -7.7    318  1.6
 11000    0.8  33.4   345    8    4   5.8   3.2   11.6  52.8    -8.0    297  1.5
 10750    1.2  34.2   340    9    4   5.5   3.0   11.2  52.2    -8.3    277  1.4
 10500    1.6  34.9   340    9    5   6.1   3.4   10.9  51.7    -8.7    257  1.3
 10250    2.0  35.6   335    9    5   3.9   2.1   10.6  51.1    -9.0    237  1.2
 10000    2.2  36.0   335    9    5   2.0   1.1   10.0  50.0    -9.6    225  1.1
  9750    2.4  36.3   330    8    4   2.9   1.6    9.5  49.1   -10.2    212  1.1
  9500    2.6  36.7   330    8    4   2.3   1.3    8.9  48.1   -10.7    199  1.0
  9250    2.8  37.0   325    8    4   3.8   2.1    8.4  47.1   -11.3    185  0.9
  9000    3.1  37.6   320    7    4   2.0   1.1    7.9  46.3   -11.7    169  0.9
  8750    3.1  37.6   310    7    4  -0.5  -0.3    7.2  45.0   -12.5    162  0.8
  8500    3.1  37.6   300    7    4  -0.1  -0.1    6.5  43.6   -13.3    154  0.8
  8250    3.0  37.4   290    7    4  -3.3  -1.8    5.6  42.1   -14.1    150  0.8
  8000    2.4  36.3   280    7    3 -14.0  -7.7    4.3  39.7   -15.5    160  0.8
  7750   -0.7  30.7   250    3    2  -6.0  -3.3   -0.3  31.5   -20.2    239  1.2
  7500      M     M     M    M    M     M     M      M     M       M      M    M
  7250      M     M     M    M    M     M     M      M     M       M      M    M
  7000      M     M     M    M    M     M     M      M     M       M      M    M
  6750      M     M     M    M    M     M     M      M     M       M      M    M

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

           10/22/2017 at 0900 MDT          |       10/22/2017 at 1200 MDT
                                           |
CAPE...     0.0    LI...       +6.7        | CAPE...     0.0    LI...       +7.5
CINH...     0.0    K Index...  +4.4        | CINH...     0.0    K Index...  +3.4
                                           |
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 -62.0 -79.6  320  22 11   1.4   0.8 | -63.0 -81.4  305  21 11   1.2   0.7
 45000 -59.9 -75.8  320  30 15   1.0   0.6 | -61.3 -78.3  315  30 16   0.5   0.3
 40000 -58.3 -72.9  335  27 14   2.6   1.4 | -60.6 -77.1  340  34 17   3.1   1.7
 38000 -55.0 -67.0  330  31 16   5.6   3.1 | -56.1 -69.0  330  31 16   7.7   4.2
 36000 -51.6 -60.9  325  36 19   5.6   3.1 | -51.5 -60.7  325  29 15   7.7   4.2
 34000 -47.2 -53.0  325  36 18   8.4   4.6 | -46.6 -51.9  315  26 13   8.5   4.7
 32000 -42.2 -44.0  325  32 17   8.4   4.6 | -40.9 -41.6  305  24 12   8.6   4.7
 30000 -37.1 -34.8  330  31 16   8.4   4.6 | -35.9 -32.6  310  23 12   8.2   4.5
 29000 -34.6 -30.3  330  31 16   8.5   4.6 | -33.5 -28.3  315  23 12   8.2   4.5
 28000 -32.1 -25.8  330  31 16   8.5   4.6 | -31.0 -23.8  325  23 12   8.2   4.5
 27000 -29.5 -21.1  330  30 16   8.6   4.7 | -28.5 -19.3  325  23 12   8.4   4.6
 26000 -26.9 -16.4  330  30 15   8.6   4.7 | -26.0 -14.8  325  23 12   8.4   4.6
 25000 -24.3 -11.7  330  29 15   8.6   4.7 | -23.5 -10.3  320  23 12   8.4   4.6
 24000 -21.8  -7.2  330  29 15   8.4   4.6 | -21.0  -5.8  320  24 12   8.4   4.6
 23000 -19.3  -2.7  330  28 14   8.4   4.6 | -18.5  -1.3  325  24 12   8.5   4.6
 22000 -16.1   3.0  330  27 14   8.6   4.7 | -15.9   3.4  325  25 13   8.5   4.6
 21000 -13.9   7.0  325  25 13   7.1   3.9 | -13.5   7.7  325  23 12   8.2   4.5
 20000 -11.8  10.8  325  24 12   7.1   3.9 | -11.1  12.0  325  21 11   8.2   4.5
 19500 -10.7  12.7  325  23 12   7.2   3.9 |  -9.3  15.3  325  19 10   8.3   4.5
 19000  -9.7  14.5  320  22 12   5.4   3.0 |  -8.1  17.4  325  19 10   7.1   3.9
 18500  -9.1  15.6  320  21 11   4.5   2.5 |  -7.1  19.2  325  19 10   7.0   3.8
 18000  -8.4  16.9  320  19 10   4.5   2.5 |  -6.1  21.0  320  19 10   6.3   3.5
 17500  -7.8  18.0  320  18  9   4.2   2.3 |  -5.4  22.3  320  19 10   3.9   2.1
 17000  -7.1  19.2  320  16  8   4.2   2.3 |  -4.8  23.4  325  19 10   4.1   2.2
 16500  -6.5  20.3  320  15  8   5.3   2.9 |  -4.3  24.3  325  18  9   2.8   1.6
 16000  -5.6  21.9  320  14  7   5.6   3.1 |  -3.9  25.0  325  17  9   2.8   1.5
 15500  -4.8  23.4  315  13  7   5.5   3.0 |  -3.5  25.7  325  16  8   2.6   1.4
 15000  -4.0  24.8  315  12  6   5.1   2.8 |  -3.2  26.2  320  14  7   2.5   1.4
 14500  -3.3  26.1  310  11  5   5.1   2.8 |  -2.8  27.0  315  13  7   2.7   1.5
 14000  -2.6  27.3  305   9  5   4.6   2.5 |  -2.3  27.9  310  12  6   3.5   1.9
 13500  -1.9  28.6  300   8  4   4.8   2.6 |  -1.8  28.8  310  11  6   3.4   1.9
 13000  -1.2  29.8  295   8  4   3.6   2.0 |  -1.2  29.8  310  10  5   4.8   2.6
 12500  -0.6  30.9  295   7  4   4.9   2.7 |  -0.3  31.5  315  10  5   7.1   3.9
 12000   0.0  32.0  295   7  3   3.9   2.2 |   0.9  33.6  320  11  6   9.5   5.2
 11750   0.3  32.5  300   6  3   3.9   2.2 |   1.6  34.9  325  11  6   9.5   5.2
 11500   0.6  33.1  300   6  3   4.1   2.2 |   2.3  36.1  325  12  6   8.1   4.5
 11250   1.0  33.8  305   5  3   6.0   3.3 |   2.8  37.0  325  12  6   5.9   3.2
 11000   1.5  34.7  310   5  3   7.7   4.2 |   3.2  37.8  325  12  6   5.6   3.1
 10750   2.1  35.8  315   5  3   7.5   4.1 |   3.6  38.5  320  12  6   6.1   3.4
 10500   2.6  36.7  320   5  3   7.8   4.3 |   4.0  39.2  320  12  6   4.3   2.4
 10250   3.2  37.8  325   5  3   7.3   4.0 |   4.2  39.6  315  13  7   3.1   1.7
 10000   3.7  38.7  325   6  3   6.2   3.4 |   4.5  40.1  310  11  6   4.0   2.2
  9750   4.1  39.4  320   6  3   6.0   3.3 |   4.8  40.6  305  10  5   3.9   2.1
  9500   4.6  40.3  320   6  3   6.4   3.5 |   5.1  41.2  300   8  4   3.4   1.9
  9250   5.1  41.2  315   7  3   6.3   3.5 |   5.4  41.7  295   7  4   6.3   3.4
  9000   5.4  41.7  315   7  4   2.2   1.2 |   6.1  43.0  295   7  4  10.6   5.8
  8750   5.5  41.9  305   8  4   0.2   0.1 |   6.9  44.4  295   7  3  11.3   6.2
  8500   5.5  41.9  300   8  4  -0.9  -0.5 |   7.7  45.9  295   6  3  10.7   5.9
  8250   5.2  41.4  295   9  5  -7.8  -4.3 |   8.5  47.3  295   6  3   9.4   5.2
  8000   4.6  40.3  290   9  4  -4.6  -2.5 |   9.3  48.7  290   6  3  14.4   7.9
  7750   4.8  40.6  280   6  3   9.2   5.0 |  10.7  51.3  295   5  3  23.8  13.1
  7500     M     M    M   M  M     M     M |     M     M    M   M  M     M     M
  7250     M     M    M   M  M     M     M |     M     M    M   M  M     M     M
  7000     M     M    M   M  M     M     M |     M     M    M   M  M     M     M
  6750     M     M    M   M  M     M     M |     M     M    M   M  M     M     M

           10/22/2017 at 1500 MDT          |       10/22/2017 at 1800 MDT
                                           |
CAPE...     0.0    LI...       +5.1        | CAPE...     0.0    LI...       +3.8
CINH...     0.0    K Index...  +8.8        | CINH...     0.0    K Index...  +7.9
                                           |
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 -63.9 -83.0  295  20 10   1.2   0.7 | -63.9 -83.0  285  22 11   2.5   1.4
 45000 -62.1 -79.8  305  29 15   0.9   0.5 | -60.5 -76.9  305  29 15   0.8   0.4
 40000 -60.6 -77.1  330  37 19   5.3   2.9 | -59.3 -74.7  320  36 18   3.0   1.6
 38000 -56.1 -69.0  325  35 18   7.5   4.1 | -55.6 -68.1  315  36 18   6.4   3.5
 36000 -51.6 -60.9  320  34 18   7.6   4.1 | -51.7 -61.1  310  36 19   6.4   3.5
 34000 -46.4 -51.5  315  31 16   9.1   5.0 | -46.3 -51.3  305  35 18   9.0   4.9
 32000 -40.9 -41.6  310  28 14   9.1   5.0 | -40.9 -41.6  310  33 17   9.0   4.9
 30000 -35.7 -32.3  310  27 14   8.4   4.6 | -35.9 -32.6  315  32 16   8.1   4.4
 29000 -33.2 -27.8  310  27 14   8.4   4.6 | -33.5 -28.3  315  31 16   8.1   4.4
 28000 -30.7 -23.3  310  27 14   8.4   4.6 | -31.1 -24.0  315  30 16   8.1   4.4
 27000 -28.3 -18.9  310  27 14   8.1   4.5 | -28.7 -19.7  315  29 15   8.2   4.5
 26000 -25.8 -14.4  315  26 13   8.1   4.5 | -26.3 -15.3  315  28 15   8.2   4.5
 25000 -22.8  -9.0  315  25 13   8.2   4.5 | -23.8 -10.8  315  27 14   8.2   4.5
 24000 -20.4  -4.7  315  23 12   7.9   4.3 | -21.5  -6.7  315  26 13   7.9   4.3
 23000 -18.1  -0.6  310  21 11   7.9   4.3 | -19.1  -2.4  315  25 13   7.9   4.3
 22000 -15.7   3.7  310  19 10   7.9   4.3 | -16.8   1.8  315  24 12   7.9   4.4
 21000 -13.3   8.1  310  19 10   8.1   4.4 | -14.5   5.9  315  23 12   7.6   4.1
 20000 -10.9  12.4  310  18  9   8.1   4.4 | -11.7  10.9  315  22 11   7.6   4.2
 19500  -9.7  14.5  315  18  9   8.2   4.5 | -10.6  12.9  315  21 11   7.5   4.1
 19000  -8.6  16.5  315  18  9   7.0   3.9 |  -9.5  14.9  315  20 10   8.2   4.5
 18500  -7.6  18.3  315  18  9   6.8   3.8 |  -8.3  17.1  315  19 10   8.1   4.4
 18000  -6.6  20.1  315  19 10   6.5   3.6 |  -7.1  19.2  315  18  9   7.8   4.3
 17500  -5.8  21.6  315  18 10   4.7   2.6 |  -6.0  21.2  315  18  9   7.2   3.9
 17000  -5.1  22.8  315  18  9   4.9   2.7 |  -4.9  23.2  315  17  9   7.3   4.0
 16500  -4.5  23.9  320  18  9   4.1   2.2 |  -3.9  25.0  320  17  9   6.4   3.5
 16000  -3.9  25.0  320  18  9   4.1   2.2 |  -3.0  26.6  320  17  9   6.5   3.6
 15500  -3.3  26.1  320  17  9   5.2   2.9 |  -2.0  28.4  320  16  8   6.0   3.3
 15000  -2.4  27.7  320  17  9   6.5   3.6 |  -1.2  29.8  325  16  8   5.9   3.2
 14500  -1.4  29.5  320  17  9   6.6   3.6 |  -0.3  31.5  325  16  8   5.8   3.2
 14000  -0.4  31.3  320  18  9   6.4   3.5 |   0.6  33.1  325  16  8   5.7   3.1
 13500   0.5  32.9  325  18 10   6.6   3.6 |   1.4  34.5  325  16  8   5.6   3.1
 13000   1.3  34.3  320  18  9   4.5   2.5 |   2.2  36.0  320  16  8   4.6   2.5
 12500   1.7  35.1  320  16  8   0.5   0.3 |   2.6  36.7  320  15  8   1.2   0.6
 12000   2.2  36.0  310  13  7   5.7   3.1 |   3.2  37.8  315  14  7   5.8   3.2
 11750   2.6  36.7  305  11  6   5.8   3.2 |   3.6  38.5  310  13  7   5.8   3.2
 11500   3.0  37.4  300   9  5   4.1   2.3 |   4.0  39.2  305  12  6   2.9   1.6
 11250   3.3  37.9  290   8  4   6.3   3.4 |   4.1  39.4  300  11  6   5.6   3.0
 11000   3.9  39.0  290   7  4  10.2   5.6 |   4.8  40.6  295  10  5  10.2   5.6
 10750   4.7  40.5  290   7  3   9.9   5.4 |   5.5  41.9  295   9  5   9.3   5.1
 10500   5.4  41.7  285   6  3   9.7   5.3 |   6.2  43.2  290   9  4   8.4   4.6
 10250   6.1  43.0  285   6  3   9.5   5.2 |   6.7  44.1  290   8  4   8.5   4.7
 10000   6.8  44.2  285   6  3   9.7   5.3 |   7.4  45.3  290   7  4  10.1   5.5
  9750   7.6  45.7  285   5  3   9.8   5.4 |   8.2  46.8  290   7  3   9.7   5.3
  9500   8.3  46.9  285   5  3   9.8   5.4 |   8.9  48.0  285   6  3   9.5   5.2
  9250   9.0  48.2  285   5  3   8.9   4.9 |   9.6  49.3  285   6  3   8.6   4.7
  9000   9.7  49.5  285   5  2   9.5   5.2 |  10.2  50.4  285   5  3   9.0   5.0
  8750  10.4  50.7  285   5  2  10.6   5.8 |  10.9  51.6  285   4  2   9.8   5.4
  8500  11.2  52.2  285   4  2  10.4   5.7 |  11.6  52.9  285   4  2   9.2   5.1
  8250  12.0  53.6  285   4  2  11.4   6.3 |  12.2  54.0  285   3  2   7.7   4.2
  8000  13.0  55.4  285   4  2  15.1   8.3 |  12.7  54.9  280   3  1   4.4   2.4
  7750  14.3  57.7  285   4  2  19.4  10.7 |  12.9  55.2  275   2  1   1.2   0.6
  7500     M     M    M   M  M     M     M |     M     M    M   M  M     M     M
  7250     M     M    M   M  M     M     M |     M     M    M   M  M     M     M
  7000     M     M    M   M  M     M     M |     M     M    M   M  M     M     M
  6750     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).  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 Air Force Academy
in Colorado Springs, Colorado at

                   North Latitude:  38 deg 58 min 48.000 sec
                   West Longitude: 104 deg 49 min 12.000 sec
                   Elevation: 6572 feet (2003 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.