Soaring Guidance
Issued by NWS Pueblo, CO

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7

000
UXUS97 KPUB 101326
SRGPUB

Soaring Forecast
National Weather Service Pueblo, Colorado
0626 MST Wednesday, January 10, 2018

This forecast is for Wednesday, January 10, 2018:

If the trigger temperature of 53.1 F/11.7 C is reached...then
   Thermal Soaring Index....................... Poor
   Maximum rate of lift........................ 0 ft/min (0.0 m/s)
   Maximum height of thermals.................. 9760 ft MSL (2147 ft AGL)

Forecast maximum temperature................... 50.0 F/10.5 C
Time of trigger temperature.................... None
Time of overdevelopment........................ 0900 MST
Middle/high clouds during soaring window....... Broken/overcast thin middle
Surface winds during soaring window............ 20 mph or less
Height of the -3 thermal index................. 8285 ft MSL (673 ft AGL)
Thermal soaring outlook for Thursday 01/11..... Poor

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

Remarks...

Sunrise/Sunset.................... 07:17:52 / 16:55:57 MST
Total possible sunshine........... 9 hr 38 min 4 sec (578 min 4 sec)
Altitude of sun at 12:06:55 MST... 29.12 degrees

Upper air data from numerical model forecast valid on 01/10/2018 at 0500 MST

Freezing level.................. 11516 ft MSL (3903 ft AGL)
Convective condensation level... 16865 ft MSL (9252 ft AGL)
Lifted condensation level....... 14172 ft MSL (6559 ft AGL)
Lifted index.................... +3.9
K index......................... +6.7

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  -57.2 -71.0   250   22   11   1.4   0.8      M     M       M      M    M
 45000  -55.1 -67.2   235   36   19   0.4   0.2      M     M       M      M    M
 40000  -58.6 -73.5   225   38   20  -2.4  -1.3      M     M       M      M    M
 38000  -58.2 -72.8   220   39   20   4.6   2.5      M     M       M      M    M
 36000  -55.5 -67.9   215   41   21   4.6   2.5      M     M       M      M    M
 34000  -52.1 -61.8   215   42   21   7.2   3.9      M     M       M      M    M
 32000  -47.8 -54.0   215   38   20   7.1   3.9      M     M       M      M    M
 30000  -43.4 -46.1   210   34   18   8.6   4.7   24.6  76.2    11.2      M    M
 29000  -40.8 -41.4   210   32   16   8.7   4.7   24.0  75.3    11.0      M    M
 28000  -38.2 -36.8   205   29   15   8.7   4.8   23.6  74.6    10.8      M    M
 27000  -35.7 -32.3   205   26   13   8.6   4.7   23.4  74.1    10.7      M    M
 26000  -33.2 -27.8   205   26   13   8.2   4.5   22.7  72.9    10.3      M    M
 25000  -30.7 -23.3   205   25   13   8.3   4.5   22.2  71.9     9.9      M    M
 24000  -28.3 -18.9   210   25   13   8.3   4.5   21.7  71.1     9.6      M    M
 23000  -25.8 -14.4   210   24   12   8.4   4.6   21.2  70.1     9.3      M    M
 22000  -23.3  -9.9   210   23   12   8.4   4.6   20.7  69.2     9.0      M    M
 21000  -20.8  -5.4   210   22   11   8.3   4.6   20.3  68.5     8.7      M    M
 20000  -17.8  -0.0   215   21   11   7.9   4.3   19.4  66.9     8.1      M    M
 19500  -16.7   1.9   215   20   10   7.9   4.3   19.1  66.4     7.8      M    M
 19000  -15.5   4.1   215   20   10   7.8   4.3   18.8  65.8     7.6      M    M
 18500  -14.3   6.3   220   19   10   7.7   4.2   18.5  65.3     7.4      M    M
 18000  -13.2   8.2   220   18    9   7.6   4.1   18.1  64.7     7.1      M    M
 17500  -12.1  10.2   220   18    9   7.6   4.2   17.8  64.0     6.8      M    M
 17000  -11.0  12.2   225   17    9   7.2   3.9   17.4  63.3     6.5      M    M
 16500   -9.9  14.2   225   16    8   7.2   4.0   17.0  62.5     6.2      M    M
 16000   -8.8  16.2   225   15    8   6.9   3.8   16.6  61.8     5.8      M    M
 15500   -7.8  18.0   230   16    8   6.6   3.6   16.0  60.9     5.4      M    M
 15000   -6.9  19.6   235   16    8   6.4   3.5   15.5  59.9     4.9      M    M
 14500   -6.0  21.2   240   16    8   5.5   3.0   14.9  58.8     4.3      M    M
 14000   -5.2  22.6   240   17    9   5.3   2.9   14.2  57.6     3.7      M    M
 13500   -4.2  24.4   245   17    9   8.8   4.8   13.8  56.8     3.3      M    M
 13000   -3.0  26.6   245   16    8   7.7   4.2   13.6  56.5     3.1      M    M
 12500   -2.3  27.9   245   15    8   4.9   2.7   12.8  55.0     2.3      M    M
 12000   -1.3  29.7   245   16    8   6.3   3.5   12.3  54.2     1.8      M    M
 11750   -0.8  30.6   245   17    9   9.1   5.0   12.1  53.8     1.6      M    M
 11500   -0.1  31.8   245   16    8   8.8   4.8   12.2  53.9     1.6      M    M
 11250    0.4  32.7   250   16    8   6.0   3.3   11.9  53.4     1.4      M    M
 11000    0.9  33.6   250   15    8   6.8   3.7   11.7  53.0     1.1      M    M
 10750    1.4  34.5   250   15    8   6.6   3.6   11.4  52.6     0.9      M    M
 10500    1.9  35.4   250   14    7   6.8   3.7   11.2  52.1     0.7      M    M
 10250    2.4  36.3   255   14    7   7.3   4.0   11.0  51.8     0.4      M    M
 10000    2.9  37.2   255   14    7   7.6   4.2   10.8  51.4     0.2      M    M
  9750    3.5  38.3   255   13    7   7.4   4.1   10.6  51.1     0.0      M    M
  9500    4.0  39.2   255   13    7   7.6   4.2   10.5  50.8    -0.1    160  0.8
  9250    4.5  40.1   260   13    7   6.2   3.4   10.3  50.5    -0.3    136  0.7
  9000    4.9  40.8   260   13    6   5.1   2.8    9.9  49.9    -0.7    118  0.6
  8750    5.2  41.4   260   12    6   2.0   1.1    9.5  49.1    -1.1    102  0.5
  8500    5.1  41.2   260   11    6  -1.7  -0.9    8.7  47.7    -1.9     96  0.5
  8250    5.0  41.0   260   11    5  -1.8  -1.0    7.9  46.2    -2.8     93  0.5
  8000    4.9  40.8   260   10    5   1.9   1.0    7.1  44.8    -3.6     87  0.4
  7750    5.0  41.0   255    7    4  -7.4  -4.0    6.4  43.5    -4.3     79  0.4
  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 * * * * * *

           01/10/2018 at 0800 MST          |       01/10/2018 at 1100 MST
                                           |
CAPE...     0.0    LI...       +1.5        | CAPE...    +8.6    LI...       +0.5
CINH...     0.0    K Index...  +8.4        | CINH...  -108.8    K Index... +15.3
                                           |
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 -56.2 -69.2  255  19 10   3.1   1.7 | -55.3 -67.5  250  17  9   2.7   1.5
 45000 -51.4 -60.5  245  29 15   2.4   1.3 | -51.0 -59.8  240  19 10   2.8   1.5
 40000 -54.1 -65.4  215  31 16  -1.9  -1.1 | -51.0 -59.8  220  27 14  -0.1  -0.1
 38000 -54.6 -66.3  210  33 17   1.1   0.6 | -51.2 -60.2  220  29 15  -0.6  -0.3
 36000 -54.0 -65.2  205  34 17   1.1   0.6 | -51.6 -60.9  215  27 14  -0.6  -0.3
 34000 -53.3 -63.9  205  34 18   2.0   1.1 | -52.0 -61.6  215  24 12   0.8   0.5
 32000 -49.8 -57.6  205  33 17   5.4   3.0 | -50.2 -58.4  215  19 10   3.0   1.6
 30000 -46.4 -51.5  200  31 16   8.4   4.6 | -48.5 -55.3  220  14  7   5.9   3.2
 29000 -43.9 -47.0  200  29 15   8.5   4.7 | -45.9 -50.6  220  13  7   8.5   4.6
 28000 -41.3 -42.3  200  28 14   8.5   4.7 | -43.4 -46.1  220  12  6   8.5   4.7
 27000 -38.8 -37.8  200  26 13   8.5   4.7 | -40.9 -41.6  220  12  6   8.5   4.7
 26000 -36.3 -33.3  200  24 12   8.5   4.6 | -38.3 -36.9  215  11  6   8.7   4.8
 25000 -33.7 -28.7  200  22 11   8.5   4.6 | -35.7 -32.3  215  11  6   8.8   4.8
 24000 -31.2 -24.2  205  19 10   8.5   4.6 | -33.1 -27.6  210  11  6   8.7   4.8
 23000 -28.7 -19.7  205  18  9   8.5   4.7 | -30.6 -23.1  210  10  5   7.8   4.3
 22000 -26.2 -15.2  210  18  9   8.5   4.7 | -28.3 -18.9  210  10  5   7.8   4.3
 21000 -23.6 -10.5  210  17  9   8.5   4.7 | -25.9 -14.6  210   9  5   7.8   4.3
 20000 -20.6  -5.1  215  17  9   8.1   4.5 | -22.6  -8.7  210   9  4   9.2   5.1
 19500 -19.4  -2.9  215  17  9   8.1   4.5 | -21.3  -6.3  210   8  4   9.2   5.1
 19000 -18.1  -0.6  215  17  9   8.1   4.5 | -19.9  -3.8  210   8  4   9.2   5.1
 18500 -16.9   1.6  220  17  9   8.0   4.4 | -18.5  -1.3  215   8  4   9.3   5.1
 18000 -15.8   3.6  220  17  9   7.4   4.1 | -17.2   1.0  215   7  4   8.6   4.7
 17500 -14.7   5.5  225  17  9   7.5   4.1 | -15.9   3.4  225   7  4   8.6   4.7
 17000 -13.6   7.5  230  17  9   7.5   4.1 | -14.6   5.7  230   7  3   8.4   4.6
 16500 -12.5   9.5  230  17  9   7.5   4.1 | -13.4   7.9  235   7  3   8.3   4.6
 16000 -11.4  11.5  235  17  9   7.6   4.2 | -12.2  10.0  245   6  3   8.3   4.6
 15500 -10.2  13.6  235  16  8   7.9   4.3 | -11.0  12.2  250   7  3   8.1   4.4
 15000  -9.0  15.8  240  15  8   7.9   4.3 |  -9.8  14.4  260   7  4   8.2   4.5
 14500  -7.8  18.0  240  15  8   8.0   4.4 |  -8.7  16.3  265   8  4   7.5   4.1
 14000  -6.6  20.1  240  15  7   8.0   4.4 |  -7.6  18.3  270   8  4   7.7   4.2
 13500  -5.5  22.1  240  14  7   7.7   4.2 |  -6.5  20.3  275   9  4   6.4   3.5
 13000  -4.3  24.3  245  14  7   7.9   4.3 |  -5.6  21.9  275   9  5   6.0   3.3
 12500  -3.4  25.9  245  13  7   5.5   3.0 |  -4.5  23.9  275   9  5   7.9   4.3
 12000  -2.5  27.5  245  13  7   6.0   3.3 |  -3.5  25.7  275  10  5   6.6   3.6
 11750  -2.0  28.4  245  14  7   9.0   4.9 |  -3.0  26.6  275  10  5   6.7   3.7
 11500  -1.3  29.7  250  13  7   8.8   4.8 |  -2.5  27.5  275   9  5   6.9   3.8
 11250  -0.9  30.4  250  13  7   5.7   3.1 |  -2.0  28.4  275   9  5   6.7   3.7
 11000  -0.4  31.3  250  12  6   6.6   3.6 |  -1.5  29.3  275   9  5   6.8   3.7
 10750   0.0  32.0  255  12  6   6.4   3.5 |  -1.0  30.2  275   9  4   6.8   3.7
 10500   0.5  32.9  255  11  6   7.0   3.8 |  -0.5  31.1  275   9  4   6.9   3.8
 10250   1.0  33.8  260  11  6   7.0   3.9 |  -0.0  32.0  280   8  4   6.8   3.7
 10000   1.5  34.7  265  10  5   6.9   3.8 |   0.5  32.9  280   8  4   6.7   3.7
  9750   2.0  35.6  265  10  5   6.9   3.8 |   0.9  33.6  285   8  4   6.7   3.7
  9500   2.5  36.5  270   9  5   6.8   3.8 |   1.4  34.5  285   8  4   6.7   3.7
  9250   3.0  37.4  270  10  5   6.4   3.5 |   1.9  35.4  285   8  4   6.8   3.8
  9000   3.4  38.1  275   9  5   6.2   3.4 |   2.4  36.3  285   8  4   7.0   3.8
  8750   3.8  38.8  275   9  5   4.9   2.7 |   2.9  37.2  285   7  4   7.3   4.0
  8500   4.1  39.4  275   9  4   2.9   1.6 |   3.4  38.1  285   7  4   8.3   4.6
  8250   4.3  39.7  275   8  4   1.7   0.9 |   4.1  39.4  285   6  3   9.0   4.9
  8000   4.4  39.9  275   8  4   3.7   2.0 |   4.7  40.5  285   6  3   8.3   4.6
  7750   4.5  40.1  275   7  4  -7.0  -3.9 |   5.4  41.7  285   5  2  10.5   5.8
  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

           01/10/2018 at 1400 MST          |       01/10/2018 at 1700 MST
                                           |
CAPE...   +35.6    LI...       -0.1        | CAPE...   +42.2    LI...       -0.5
CINH...   -19.3    K Index... +22.2        | CINH...   -17.2    K Index... +19.0
                                           |
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 -54.7 -66.5  245  18  9   3.0   1.6 | -53.9 -65.0  255  17  9   2.0   1.1
 45000 -50.2 -58.4  245  16  8   3.0   1.6 | -51.0 -59.8  260  14  7   2.0   1.1
 40000 -51.5 -60.7  240  19 10  -1.2  -0.6 | -50.5 -58.9  255  14  7   0.2   0.1
 38000 -52.1 -61.8  235  19 10  -0.7  -0.4 | -50.9 -59.6  255  14  7  -2.7  -1.5
 36000 -52.6 -62.7  235  17  9  -0.7  -0.4 | -52.5 -62.5  260  14  7  -2.8  -1.5
 34000 -53.0 -63.4  230  15  8  -1.1  -0.6 | -54.2 -65.6  270  13  7  -3.6  -2.0
 32000 -51.3 -60.3  245  11  6   3.4   1.9 | -52.1 -61.8  270  12  6   4.4   2.4
 30000 -49.2 -56.6  275   8  4   4.1   2.2 | -49.5 -57.1  270  10  5   4.6   2.5
 29000 -46.7 -52.1  280   8  4   9.5   5.2 | -46.9 -52.4  265  10  5   9.5   5.2
 28000 -43.8 -46.8  285   8  4   9.5   5.2 | -44.1 -47.4  260   9  5   9.4   5.2
 27000 -41.0 -41.8  285   7  4   9.4   5.2 | -41.3 -42.3  255   8  4   9.4   5.2
 26000 -38.3 -36.9  285   7  4   8.6   4.7 | -38.6 -37.5  250   7  4   8.5   4.7
 25000 -35.7 -32.3  270   8  4   8.6   4.7 | -36.0 -32.8  245   6  3   8.5   4.7
 24000 -32.5 -26.5  255   8  4   8.6   4.7 | -33.5 -28.3  230   4  2   8.5   4.7
 23000 -30.0 -22.0  245   9  4   8.0   4.4 | -31.0 -23.8  215   3  1   8.0   4.4
 22000 -27.6 -17.7  245   8  4   8.0   4.4 | -28.0 -18.4  260   1  1   8.1   4.4
 21000 -25.3 -13.5  240   7  4   7.9   4.4 | -25.6 -14.1  315   2  1   8.2   4.5
 20000 -22.9  -9.2  240   6  3   8.2   4.5 | -23.3  -9.9  330   4  2   7.2   4.0
 19500 -21.7  -7.1  240   6  3   8.2   4.5 | -22.3  -8.1  330   5  2   7.2   4.0
 19000 -20.4  -4.7  240   5  3   8.3   4.5 | -21.2  -6.2  330   6  3   7.2   4.0
 18500 -19.2  -2.6  240   5  2   8.4   4.6 | -20.1  -4.2  330   7  4   7.3   4.0
 18000 -18.1  -0.6  245   4  2   7.8   4.3 | -19.1  -2.4  330   8  4   6.5   3.6
 17500 -16.9   1.6  255   4  2   7.7   4.2 | -18.2  -0.8  330   9  5   6.4   3.5
 17000 -15.8   3.6  270   3  2   7.6   4.2 | -17.2   1.0  330  10  5   6.6   3.6
 16500 -14.7   5.5  280   4  2   7.3   4.0 | -16.2   2.8  335  11  6   7.0   3.8
 16000 -13.6   7.5  290   5  2   7.4   4.0 | -15.2   4.6  335  12  6   7.0   3.8
 15500 -12.5   9.5  295   6  3   7.1   3.9 | -14.1   6.6  335  13  6   7.0   3.9
 15000 -11.5  11.3  300   7  3   7.2   3.9 | -13.1   8.4  330  13  7   7.0   3.8
 14500 -10.4  13.3  300   7  4   7.1   3.9 | -12.1  10.2  330  14  7   7.3   4.0
 14000  -9.4  15.1  300   7  4   7.1   3.9 | -11.0  12.2  330  14  7   7.3   4.0
 13500  -8.4  16.9  300   7  4   6.6   3.6 |  -9.9  14.2  330  14  7   6.3   3.5
 13000  -7.4  18.7  305   6  3   5.7   3.1 |  -9.1  15.6  325  14  7   4.9   2.7
 12500  -5.9  21.4  305   6  3  11.7   6.4 |  -7.9  17.8  320  14  7  10.0   5.5
 12000  -4.7  23.5  300   6  3   7.9   4.3 |  -6.8  19.8  315  14  7   7.3   4.0
 11750  -4.1  24.6  300   6  3   8.0   4.4 |  -6.3  20.7  315  13  7   6.2   3.4
 11500  -3.5  25.7  300   5  3   9.1   5.0 |  -5.8  21.6  315  13  7   9.9   5.4
 11250  -2.8  27.0  300   5  2   8.6   4.7 |  -5.0  23.0  315  13  7  10.3   5.7
 11000  -2.3  27.9  300   4  2   7.7   4.2 |  -4.4  24.1  315  12  6   7.0   3.8
 10750  -1.7  28.9  300   4  2   8.0   4.4 |  -3.8  25.2  315  12  6   8.2   4.5
 10500  -1.1  30.0  300   3  2   7.8   4.3 |  -3.3  26.1  315  11  6   6.9   3.8
 10250  -0.5  31.1  310   3  2   8.6   4.7 |  -2.8  27.0  315  11  6   7.2   4.0
 10000   0.2  32.4  320   3  1   9.5   5.2 |  -2.2  28.0  315  10  5   8.3   4.6
  9750   0.9  33.6  330   3  1   9.0   4.9 |  -1.6  29.1  315  10  5   8.5   4.6
  9500   1.5  34.7  345   2  1  10.1   5.5 |  -1.1  30.0  315   9  5   6.7   3.6
  9250   2.4  36.3  345   2  1  10.8   5.9 |  -0.7  30.7  315   9  5   5.0   2.7
  9000   3.1  37.6  345   2  1  10.0   5.5 |  -0.3  31.5  315   8  4   5.9   3.2
  8750   3.9  39.0  350   2  1  10.0   5.5 |   0.1  32.2  310   8  4   5.7   3.1
  8500   4.6  40.3  350   3  1   9.7   5.3 |   0.5  32.9  310   7  4   4.2   2.3
  8250   5.3  41.5  355   3  1   9.7   5.3 |   0.7  33.3  310   7  4   3.2   1.8
  8000   6.0  42.8  355   3  1   8.9   4.9 |   1.0  33.8  315   6  3   4.8   2.6
  7750   8.4  47.1  355   3  1  39.3  21.6 |   1.4  34.5  315   6  3   8.4   4.6
  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.