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 8 9 10 11 12 13
000
UXUS97 KPUB 041024
SRGPUB

Soaring Forecast
National Weather Service Pueblo, Colorado
0424 MDT Friday, September 4, 2015

This forecast is for Friday, September 4, 2015:

If the trigger temperature of 72.9 F/22.7 C is reached...then
   Thermal Soaring Index....................... Excellent
   Maximum rate of lift........................ 904 ft/min (4.6 m/s)
   Maximum height of thermals.................. 16315 ft MSL (9557 ft AGL)

Forecast maximum temperature................... 78.0 F/26.0 C
Time of trigger temperature.................... 1045 MDT
Time of overdevelopment........................ None
Middle/high clouds during soaring window....... Overcast opaque high
Surface winds during soaring window............ 20 mph or less
Height of the -3 thermal index................. 10141 ft MSL (3384 ft AGL)
Thermal soaring outlook for Saturday 09/05..... Good

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

Remarks...

Sunrise/Sunset.................... 06:30:20 / 19:26:28 MDT
Total possible sunshine........... 12 hr 56 min 8 sec (776 min 8 sec)
Altitude of sun at 12:57:58 MDT... 58.14 degrees

Upper air data from numerical model forecast valid on 09/04/2015 at 0600 MDT

Freezing level.................. 15504 ft MSL (8746 ft AGL)
Convective condensation level... 15721 ft MSL (8963 ft AGL)
Lifted condensation level....... 15559 ft MSL (8802 ft AGL)
Lifted index.................... -2.0
K index......................... +28.4

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  -63.0 -81.4   245   39   20  -0.0  -0.0      M     M       M      M    M
 45000  -61.3 -78.3   245   48   25   4.6   2.5      M     M       M      M    M
 40000  -53.7 -64.7   255   72   37   7.0   3.9      M     M       M      M    M
 38000  -49.4 -56.9   250   68   35   7.1   3.9      M     M       M      M    M
 36000  -45.1 -49.2   245   64   33   7.1   3.9      M     M       M      M    M
 34000  -40.6 -41.1   245   57   29   7.5   4.1      M     M       M      M    M
 32000  -36.1 -33.0   245   49   25   7.6   4.2      M     M       M      M    M
 30000  -31.3 -24.3   245   40   21   8.3   4.5   39.0 102.2    10.4      M    M
 29000  -28.2 -18.8   240   34   18   8.3   4.5   38.3 101.0    10.0      M    M
 28000  -25.7 -14.3   235   30   16   7.4   4.1   37.9 100.1     9.8      M    M
 27000  -23.6 -10.5   235   30   16   7.1   3.9   36.7  98.1     9.0      M    M
 26000  -21.5  -6.7   230   31   16   7.2   4.0   35.8  96.4     8.2      M    M
 25000  -19.4  -2.9   225   31   16   7.3   4.0   35.0  95.0     7.6      M    M
 24000  -17.4   0.7   225   29   15   6.7   3.7   33.8  92.9     6.7      M    M
 23000  -15.3   4.5   225   26   14   6.7   3.7   32.7  90.9     5.9      M    M
 22000  -13.3   8.1   225   24   12   6.8   3.7   31.7  89.1     5.2      M    M
 21000  -11.2  11.8   225   21   11   7.1   3.9   30.7  87.3     4.4      M    M
 20000   -9.1  15.6   230   19   10   7.1   3.9   29.8  85.7     3.6      M    M
 19500   -8.0  17.6   230   18    9   7.2   3.9   29.4  85.0     3.2      M    M
 19000   -7.0  19.4   230   17    9   6.7   3.7   29.0  84.2     2.8      M    M
 18500   -6.1  21.0   235   16    8   6.7   3.7   28.4  83.2     2.3      M    M
 18000   -5.2  22.6   235   15    7   6.9   3.8   28.0  82.3     1.8      M    M
 17500   -4.2  24.4   240   14    7   7.0   3.8   27.5  81.4     1.3      M    M
 17000   -3.3  26.1   240   13    7   7.1   3.9   27.0  80.6     0.7      M    M
 16500   -2.3  27.9   245   12    6   7.4   4.0   26.6  79.9     0.2      M    M
 16000   -1.3  29.7   245   11    6   7.4   4.1   26.2  79.2    -0.2    884  4.5
 15500   -0.2  31.6   245   10    5   7.8   4.3   25.8  78.5    -0.6    838  4.3
 15000    0.9  33.6   245   10    5   8.3   4.5   25.6  78.0    -0.9    788  4.0
 14500    2.7  36.9   245    9    5   8.3   4.5   25.2  77.4    -1.3    712  3.6
 14000    3.9  39.0   245    9    5   8.3   4.5   25.0  77.0    -1.6    663  3.4
 13500    5.0  41.0   245   10    5   8.7   4.8   24.8  76.6    -1.9    613  3.1
 13000    6.4  43.5   245    9    5   9.2   5.0   24.7  76.4    -2.0    558  2.8
 12500    7.7  45.9   245    9    5   7.7   4.2   24.6  76.3    -2.1    502  2.6
 12000    8.9  48.0   250    9    5   9.3   5.1   24.3  75.7    -2.4    452  2.3
 11750    9.6  49.3   250    9    5   8.7   4.8   24.2  75.6    -2.5    425  2.2
 11500   10.3  50.5   250    9    5   9.1   5.0   24.1  75.5    -2.5    397  2.0
 11250   11.0  51.8   255    9    4   8.6   4.7   24.1  75.4    -2.6    369  1.9
 11000   11.6  52.9   260    9    5   7.9   4.3   24.0  75.1    -2.7    342  1.7
 10750   12.3  54.1   265    9    5   8.1   4.4   23.8  74.9    -2.8    316  1.6
 10500   12.9  55.2   270   10    5   8.0   4.4   23.7  74.7    -2.8    289  1.5
 10250   13.5  56.3   275   10    5   7.7   4.2   23.6  74.4    -3.0    263  1.3
 10000   14.1  57.4   275   10    5   7.8   4.3   23.4  74.1    -3.1    239  1.2
  9750   14.7  58.5   275   11    5   8.2   4.5   23.3  73.9    -3.3    214  1.1
  9500   15.3  59.5   275   11    6   8.0   4.4   23.2  73.7    -3.4    188  1.0
  9250   15.8  60.4   280   11    6   7.3   4.0   23.0  73.4    -3.6    164  0.8
  9000   16.3  61.3   280   11    6   7.1   3.9   22.8  73.0    -3.8    141  0.7
  8750   16.9  62.4   280   11    6   8.1   4.5   22.6  72.7    -4.0    118  0.6
  8500   17.4  63.3   280   12    6   6.8   3.7   22.5  72.5    -4.2     95  0.5
  8250   17.7  63.9   280   12    6   4.0   2.2   22.1  71.9    -4.7     78  0.4
  8000   17.9  64.2   280   12    6   0.5   0.3   21.6  70.9    -5.2     66  0.3
  7750   18.0  64.4   280   13    7   9.8   5.4   21.1  69.9    -5.8     53  0.3
  7500   18.7  65.7   280   13    7  -3.5  -1.9   21.1  69.9    -5.9     26  0.1
  7250   17.1  62.8   280   11    6 -32.0 -17.6   19.1  66.3    -7.9     68  0.3
  7000   14.8  58.6   280    9    5 -22.7 -12.4   16.5  61.7   -10.5    128  0.7
  6750      M     M     M    M    M     M     M      M     M       M      M    M

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

           09/04/2015 at 0900 MDT          |       09/04/2015 at 1200 MDT
                                           |
K index... +12.5  LI... +272.2             | K index... +25.7  LI... +273.1
CAPE... +30.4  CIN... -46.1                | CAPE... +28.6  CIN... -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 -63.4 -82.1  250  42 22  -0.2  -0.1 | -63.9 -83.0  250  42 22   0.1   0.1
 45000 -61.4 -78.5  255  58 30   5.1   2.8 | -61.2 -78.2  250  59 30   5.4   2.9
 40000 -53.4 -64.1  255  74 38   6.7   3.7 | -53.0 -63.4  250  77 40   6.3   3.5
 38000 -49.3 -56.7  250  66 34   6.8   3.7 | -49.2 -56.6  245  69 35   6.3   3.5
 36000 -45.2 -49.4  245  59 30   6.7   3.7 | -45.4 -49.7  245  61 31   6.1   3.4
 34000 -40.6 -41.1  240  54 28   8.0   4.4 | -40.5 -40.9  240  52 27   8.5   4.6
 32000 -35.7 -32.3  235  49 25   7.9   4.3 | -35.5 -31.9  230  43 22   8.3   4.5
 30000 -30.4 -22.7  230  42 22   8.1   4.4 | -29.8 -21.6  225  39 20   8.5   4.7
 29000 -28.0 -18.4  225  38 20   8.1   4.4 | -27.3 -17.1  220  38 19   8.5   4.7
 28000 -25.6 -14.1  225  35 18   7.2   3.9 | -24.8 -12.6  220  37 19   7.3   4.0
 27000 -23.6 -10.5  220  34 18   6.9   3.8 | -22.7  -8.9  215  34 18   7.0   3.8
 26000 -21.6  -6.9  220  33 17   6.9   3.8 | -20.7  -5.3  215  31 16   7.0   3.8
 25000 -19.5  -3.1  220  32 16   6.9   3.8 | -18.6  -1.5  215  29 15   7.1   3.9
 24000 -17.5   0.5  220  29 15   7.0   3.8 | -16.5   2.3  215  26 14   7.4   4.1
 23000 -15.5   4.1  225  26 14   7.0   3.8 | -14.3   6.3  215  24 12   7.5   4.1
 22000 -13.4   7.9  230  23 12   6.9   3.8 | -12.1  10.2  215  21 11   7.3   4.0
 21000 -11.6  11.1  230  22 11   6.1   3.4 | -10.3  13.5  210  21 11   6.2   3.4
 20000  -9.7  14.5  230  20 10   6.1   3.3 |  -8.5  16.7  205  21 11   6.3   3.4
 19500  -8.8  16.2  235  19 10   5.9   3.3 |  -7.6  18.3  205  21 11   6.3   3.5
 19000  -7.8  18.0  230  18 10   8.4   4.6 |  -6.7  19.9  205  21 11   5.2   2.9
 18500  -6.4  20.5  230  18  9   8.6   4.7 |  -6.0  21.2  200  20 10   5.1   2.8
 18000  -5.1  22.8  230  17  9   8.3   4.5 |  -5.2  22.6  200  20 10   5.0   2.7
 17500  -4.0  24.8  230  17  9   6.9   3.8 |  -4.6  23.7  200  18  9   4.3   2.4
 17000  -2.9  26.8  225  16  8   6.9   3.8 |  -3.9  25.0  200  17  9   4.3   2.3
 16500  -1.9  28.6  225  15  8   6.9   3.8 |  -3.2  26.2  200  16  8   5.3   2.9
 16000  -1.0  30.2  220  14  7   7.1   3.9 |  -2.4  27.7  200  15  8   5.4   3.0
 15500  -0.0  32.0  220  13  7   7.5   4.1 |  -1.6  29.1  200  14  7   6.4   3.5
 15000   1.0  33.8  215  12  6   7.8   4.3 |   0.1  32.2  200  13  6   7.5   4.1
 14500   2.7  36.9  215  10  5   8.5   4.7 |   1.3  34.3  205  12  6   9.8   5.4
 14000   3.9  39.0  210   9  4   8.7   4.8 |   2.9  37.2  205  12  6  10.5   5.7
 13500   5.2  41.4  210   7  4   8.9   4.9 |   4.5  40.1  205  11  6  10.5   5.7
 13000   6.6  43.9  210   6  3   9.0   5.0 |   6.1  43.0  205  11  6  10.3   5.6
 12500   8.0  46.4  210   5  3   8.0   4.4 |   7.6  45.7  205  10  5   8.3   4.5
 12000   9.2  48.6  210   5  3   8.3   4.5 |   8.8  47.8  200  10  5  10.0   5.5
 11750   9.8  49.6  205   5  2   7.7   4.2 |   9.5  49.1  200   9  5   9.4   5.1
 11500  10.4  50.7  205   4  2   8.9   4.9 |  10.2  50.4  200   8  4   9.6   5.3
 11250  11.2  52.2  205   4  2   8.8   4.8 |  10.9  51.6  195   8  4   9.7   5.3
 11000  11.7  53.1  215   4  2   7.4   4.1 |  11.6  52.9  195   7  4   9.7   5.3
 10750  12.3  54.1  225   3  2   7.7   4.2 |  12.3  54.1  195   7  4   9.8   5.4
 10500  12.8  55.0  240   3  1   7.6   4.2 |  13.0  55.4  190   7  4   9.4   5.2
 10250  13.4  56.1  255   3  1   7.8   4.3 |  13.7  56.7  185   7  3   8.1   4.5
 10000  14.0  57.2  265   3  2   8.3   4.6 |  14.2  57.6  185   6  3   9.1   5.0
  9750  14.6  58.3  275   3  2   8.8   4.8 |  15.0  59.0  180   6  3  10.5   5.8
  9500  15.2  59.4  285   4  2   8.4   4.6 |  15.8  60.4  180   7  3   9.7   5.3
  9250  15.8  60.4  285   4  2   7.5   4.1 |  16.4  61.5  180   7  3   8.3   4.5
  9000  16.3  61.3  285   5  2   7.4   4.1 |  17.0  62.6  180   7  4   8.5   4.7
  8750  16.8  62.2  280   5  2   8.6   4.7 |  17.7  63.9  175   7  4  11.0   6.0
  8500  17.5  63.5  280   5  3   8.2   4.5 |  18.5  65.3  175   7  4  11.3   6.2
  8250  18.0  64.4  275   6  3   6.7   3.7 |  19.3  66.7  175   7  4  10.2   5.6
  8000  18.4  65.1  275   6  3   6.4   3.5 |  20.0  68.0  175   7  4  10.0   5.5
  7750  18.8  65.8  275   6  3   6.7   3.7 |  20.8  69.4  175   7  4  10.5   5.8
  7500  19.2  66.6  270   7  3   5.3   2.9 |  21.6  70.9  175   7  4  11.5   6.3
  7250  19.4  66.9  270   6  3   3.9   2.2 |  22.4  72.3  170   7  4  11.8   6.5
  7000  19.6  67.3  270   5  3   4.9   2.7 |  23.3  73.9  170   7  4  11.7   6.4
  6750     M     M    M   M  M     M     M |     M     M    M   M  M     M     M

           09/04/2015 at 1500 MDT          |       09/04/2015 at 1800 MDT
                                           |
K index... +25.6  LI... +273.4             | K index... +30.0  LI... +272.5
CAPE... 0.0  CIN... -0.6                   | CAPE... +4.2  CIN... -12.6
                                           |
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 -64.5 -84.1  250  45 23   0.0   0.0 | -65.4 -85.7  245  48 25  -0.3  -0.2
 45000 -61.7 -79.1  250  67 34   5.8   3.2 | -62.6 -80.7  250  73 38   6.6   3.6
 40000 -52.8 -63.0  250  81 42   7.0   3.8 | -52.5 -62.5  245  80 41   7.7   4.2
 38000 -48.6 -55.5  245  73 38   7.0   3.9 | -47.9 -54.2  245  75 38   7.7   4.2
 36000 -44.4 -47.9  245  66 34   6.8   3.8 | -43.3 -45.9  245  69 36   7.6   4.2
 34000 -39.4 -38.9  240  58 30   8.5   4.7 | -38.3 -36.9  245  61 32   8.3   4.6
 32000 -34.3 -29.7  240  50 26   8.3   4.6 | -32.7 -26.9  245  52 27   9.0   5.0
 30000 -28.7 -19.7  235  45 23   8.2   4.5 | -27.8 -18.0  240  46 24   8.0   4.4
 29000 -26.3 -15.3  230  44 23   8.2   4.5 | -25.4 -13.7  240  44 22   8.0   4.4
 28000 -23.9 -11.0  225  43 22   7.5   4.1 | -23.1  -9.6  235  41 21   7.2   3.9
 27000 -21.7  -7.1  225  41 21   7.3   4.0 | -21.0  -5.8  235  39 20   7.0   3.9
 26000 -19.6  -3.3  230  39 20   7.4   4.0 | -19.0  -2.2  235  37 19   7.1   3.9
 25000 -17.4   0.7  230  38 19   7.3   4.0 | -16.9   1.6  230  35 18   7.1   3.9
 24000 -15.5   4.1  225  35 18   6.3   3.5 | -15.0   5.0  230  33 17   6.4   3.5
 23000 -13.7   7.3  225  32 16   6.4   3.5 | -13.1   8.4  225  31 16   6.5   3.5
 22000 -11.8  10.8  220  29 15   6.3   3.5 | -11.3  11.7  225  29 15   6.5   3.5
 21000 -10.0  14.0  215  27 14   6.1   3.4 |  -9.5  14.9  220  27 14   6.2   3.4
 20000  -8.2  17.2  210  25 13   6.2   3.4 |  -7.7  18.1  210  26 13   6.2   3.4
 19500  -7.3  18.9  210  24 12   6.2   3.4 |  -6.8  19.8  210  25 13   6.2   3.4
 19000  -6.5  20.3  210  23 12   5.9   3.2 |  -5.9  21.4  205  25 13   6.0   3.3
 18500  -5.6  21.9  210  23 12   5.9   3.2 |  -5.1  22.8  200  25 13   5.9   3.3
 18000  -4.8  23.4  205  23 12   6.0   3.3 |  -4.3  24.3  195  26 13   6.0   3.3
 17500  -3.9  25.0  205  23 12   6.5   3.6 |  -3.3  26.1  190  26 14   6.7   3.7
 17000  -2.9  26.8  205  22 12   6.6   3.6 |  -2.4  27.7  185  27 14   6.8   3.7
 16500  -2.0  28.4  205  22 11   6.1   3.3 |  -1.5  29.3  180  28 14   5.5   3.0
 16000  -1.1  30.0  200  21 11   6.0   3.3 |  -0.7  30.7  180  27 14   5.2   2.9
 15500  -0.2  31.6  195  21 11   6.4   3.5 |   0.5  32.9  175  26 13   6.8   3.7
 15000   1.3  34.3  185  20 10   6.9   3.8 |   1.5  34.7  175  24 12   6.8   3.8
 14500   2.4  36.3  180  20 10   7.8   4.3 |   2.5  36.5  175  22 12   7.3   4.0
 14000   3.6  38.5  175  20 10   8.2   4.5 |   3.6  38.5  175  21 11   7.6   4.2
 13500   4.9  40.8  175  20 10   8.6   4.7 |   4.7  40.5  175  20 10   7.8   4.3
 13000   6.2  43.2  170  20 10   9.1   5.0 |   5.9  42.6  175  18  9   8.0   4.4
 12500   7.6  45.7  170  19 10   8.7   4.8 |   7.1  44.8  180  17  9   6.6   3.6
 12000   8.9  48.0  170  18  9   9.0   4.9 |   8.0  46.4  180  15  8   7.7   4.2
 11750   9.5  49.1  170  18  9   9.0   4.9 |   8.6  47.5  185  14  7   7.5   4.1
 11500  10.1  50.2  170  17  9   8.4   4.6 |   9.1  48.4  185  13  7   6.9   3.8
 11250  10.8  51.4  170  16  8   8.9   4.9 |   9.7  49.5  185  13  7   8.0   4.4
 11000  11.5  52.7  170  15  8   9.9   5.4 |  10.3  50.5  185  12  6   9.5   5.2
 10750  12.2  54.0  170  15  8   9.7   5.3 |  11.0  51.8  190  11  6   9.3   5.1
 10500  12.9  55.2  170  14  7   9.6   5.3 |  11.7  53.1  190  11  5   9.2   5.1
 10250  13.6  56.5  170  13  7   9.0   4.9 |  12.4  54.3  190  10  5   6.6   3.6
 10000  14.2  57.6  170  13  7   9.6   5.3 |  12.8  55.0  190  10  5   8.4   4.6
  9750  15.0  59.0  170  13  7  10.5   5.8 |  13.6  56.5  190  10  5  11.4   6.3
  9500  15.8  60.4  170  13  7  10.1   5.6 |  14.5  58.1  190  10  5  10.5   5.7
  9250  16.5  61.7  170  13  7   9.4   5.2 |  15.2  59.4  190  10  5   9.5   5.2
  9000  17.2  63.0  170  13  6   9.5   5.2 |  15.9  60.6  190  10  5   9.1   5.0
  8750  17.9  64.2  175  13  6  10.7   5.9 |  16.6  61.9  190  10  5  10.2   5.6
  8500  18.8  65.8  170  13  6  10.9   6.0 |  17.4  63.3  190  10  5  10.4   5.7
  8250  19.5  67.1  175  12  6  10.4   5.7 |  18.1  64.6  190   9  5  10.0   5.5
  8000  20.3  68.5  175  12  6  10.6   5.8 |  18.9  66.0  190   9  5  10.0   5.5
  7750  21.1  70.0  175  12  6   9.5   5.2 |  19.6  67.3  190   9  5   9.7   5.3
  7500  21.8  71.2  175  12  6  10.4   5.7 |  20.3  68.5  190   9  5   8.3   4.5
  7250  22.6  72.7  175  12  6  13.2   7.2 |  20.8  69.4  190   9  4   7.1   3.9
  7000  23.6  74.5  175  11  6  12.1   6.7 |  21.3  70.3  190   8  4   7.2   4.0
  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) 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 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.