Soaring Guidance
Issued by NWS Pueblo, CO

Home | Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14
000
UXUS97 KPUB 291238
SRGPUB

Soaring Forecast
National Weather Service Pueblo, Colorado
0638 MDT Wednesday, April 29, 2015

This forecast is for Wednesday, April 29, 2015:

If the trigger temperature of 57.0 F/13.9 C is reached...then
   Thermal Soaring Index....................... Excellent
   Maximum rate of lift........................ 880 ft/min (4.5 m/s)
   Maximum height of thermals.................. 16851 ft MSL (10093 ft AGL)

Forecast maximum temperature................... 68.0 F/20.5 C
Time of trigger temperature.................... 0845 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................. 14434 ft MSL (7676 ft AGL)
Thermal soaring outlook for Thursday 04/30..... Good

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

Remarks...

Sunrise/Sunset.................... 06:03:53 / 19:48:38 MDT
Total possible sunshine........... 13 hr 44 min 46 sec (824 min 46 sec)
Altitude of sun at 12:56:26 MDT... 65.59 degrees

Upper air data from numerical model forecast valid on 04/29/2015 at 0600 MDT

Freezing level.................. 12154 ft MSL (5396 ft AGL)
Convective condensation level... 14739 ft MSL (7981 ft AGL)
Lifted condensation level....... 15509 ft MSL (8751 ft AGL)
Lifted index.................... -1.9
K index......................... -6.6

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  -60.7 -77.3   345   22   11   3.0   1.6      M     M       M      M    M
 45000  -56.8 -70.2   005   31   16  -1.2  -0.6      M     M       M      M    M
 40000  -58.7 -73.7   040   46   23  -1.2  -0.7      M     M       M      M    M
 38000  -56.5 -69.7   040   46   24   5.1   2.8      M     M       M      M    M
 36000  -53.5 -64.3   045   44   23   5.1   2.8      M     M       M      M    M
 34000  -49.6 -57.3   045   43   22   8.3   4.5      M     M       M      M    M
 32000  -44.7 -48.5   040   43   22   8.3   4.5      M     M       M      M    M
 30000  -39.2 -38.6   030   41   21   8.0   4.4   30.3  86.6     7.9      M    M
 29000  -36.8 -34.2   025   38   20   8.0   4.4   29.6  85.3     7.5      M    M
 28000  -34.4 -29.9   020   36   19   8.0   4.4   29.1  84.3     7.2      M    M
 27000  -32.0 -25.6   020   34   17   7.6   4.2   28.4  83.0     6.7      M    M
 26000  -29.8 -21.6   015   32   16   7.6   4.2   27.5  81.5     6.0      M    M
 25000  -27.5 -17.5   010   30   15   7.6   4.2   26.7  80.1     5.5      M    M
 24000  -25.2 -13.4   010   28   14   7.8   4.3   26.0  78.8     5.0      M    M
 23000  -22.9  -9.2   005   25   13   7.7   4.2   25.2  77.4     4.3      M    M
 22000  -20.6  -5.1   005   22   11   7.7   4.2   24.6  76.2     3.8      M    M
 21000  -18.3  -0.9   005   19   10   7.4   4.1   23.8  74.9     3.2      M    M
 20000  -16.0   3.2   360   17    9   7.4   4.1   23.0  73.3     2.6      M    M
 19500  -14.9   5.2   360   16    8   7.4   4.1   22.6  72.7     2.2      M    M
 19000  -13.8   7.2   360   14    7   7.4   4.1   22.2  72.0     1.9      M    M
 18500  -12.8   9.0   360   14    7   6.1   3.3   21.7  71.1     1.5      M    M
 18000  -11.9  10.6   360   13    7   6.2   3.4   21.1  70.0     1.0      M    M
 17500  -10.9  12.4   360   13    7   7.1   3.9   20.6  69.0     0.5      M    M
 17000   -9.8  14.4   360   12    6   7.5   4.1   20.2  68.3     0.2      M    M
 16500   -8.6  16.5   360   12    6   7.3   4.0   19.8  67.7    -0.2    854  4.3
 16000   -7.7  18.1   360   12    6   5.8   3.2   19.3  66.7    -0.7    811  4.1
 15500   -6.8  19.8   355   13    7   5.9   3.3   18.6  65.5    -1.3    770  3.9
 15000   -6.0  21.2   350   14    7   5.1   2.8   17.9  64.3    -1.9    731  3.7
 14500   -4.9  23.2   340   17    9   5.8   3.2   16.9  62.3    -3.1    677  3.4
 14000   -4.0  24.8   340   17    9   7.2   4.0   16.3  61.4    -3.7    635  3.2
 13500   -3.1  26.4   335   17    9   7.3   4.0   15.9  60.7    -4.2    591  3.0
 13000   -1.9  28.6   335   17    9   9.3   5.1   15.7  60.3    -4.5    542  2.8
 12500   -0.6  30.9   335   17    9   8.9   4.9   15.6  60.1    -4.7    488  2.5
 12000    0.5  32.9   335   17    9   8.0   4.4   15.4  59.7    -5.0    438  2.2
 11750    1.1  34.0   335   17    9   8.1   4.4   15.2  59.4    -5.2    413  2.1
 11500    1.7  35.1   340   17    9   8.2   4.5   15.1  59.2    -5.4    389  2.0
 11250    2.3  36.1   340   16    8   7.6   4.2   15.0  59.0    -5.5    364  1.8
 11000    2.8  37.0   335   16    8   7.2   4.0   14.8  58.6    -5.7    340  1.7
 10750    3.4  38.1   335   15    8   7.6   4.2   14.6  58.3    -5.9    316  1.6
 10500    3.9  39.0   335   15    7   7.5   4.1   14.4  58.0    -6.1    292  1.5
 10250    4.5  40.1   335   14    7   7.5   4.1   14.3  57.7    -6.3    268  1.4
 10000    5.1  41.2   335   13    6   8.1   4.4   14.1  57.4    -6.5    244  1.2
  9750    5.7  42.3   335   11    6   8.7   4.8   14.0  57.3    -6.6    218  1.1
  9500    6.3  43.3   335   10    5   9.0   4.9   14.0  57.1    -6.7    191  1.0
  9250    7.0  44.6   335    9    5   6.7   3.7   13.9  56.9    -6.8    165  0.8
  9000    7.3  45.1   335    8    4   4.7   2.6   13.5  56.3    -7.2    146  0.7
  8750    7.8  46.0   330    7    4   7.8   4.3   13.2  55.8    -7.5    126  0.6
  8500    8.4  47.1   330    7    3   7.5   4.1   13.1  55.6    -7.6     99  0.5
  8250    8.8  47.8   325    6    3   2.0   1.1   12.7  54.9    -8.0     81  0.4
  8000    8.7  47.7   315    6    3  -4.2  -2.3   11.9  53.5    -8.8     75  0.4
  7750    8.6  47.5   310    6    3   9.0   5.0   11.1  52.0    -9.6     70  0.4
  7500    9.4  48.9   295    7    3  -4.5  -2.4   11.2  52.1    -9.6     40  0.2
  7250    7.5  45.5   290    7    3 -38.7 -21.2    8.8  47.9   -11.9     91  0.5
  7000    4.7  40.5   290    7    3 -27.9 -15.3    5.8  42.4   -15.0    166  0.8
  6750      M     M     M    M    M     M     M      M     M       M      M    M

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

           04/29/2015 at 0900 MDT          |       04/29/2015 at 1200 MDT
                                           |
K index... -7.3  LI... +275.7              | K index... +1.3  LI... +275.0
CAPE... 0.0  CIN... M                      | CAPE... 0.0  CIN... M
                                           |
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 -60.9 -77.6  350  23 12   2.3   1.2 | -61.5 -78.7  355  21 11   2.2   1.2
 45000 -58.0 -72.4  005  30 16  -1.0  -0.6 | -58.7 -73.7  010  25 13  -0.8  -0.4
 40000 -59.6 -75.3  045  40 21  -1.3  -0.7 | -59.9 -75.8  050  31 16  -1.3  -0.7
 38000 -56.8 -70.2  050  40 21   6.2   3.4 | -56.8 -70.2  050  31 16   6.6   3.6
 36000 -53.1 -63.6  050  40 20   6.2   3.4 | -52.8 -63.0  045  30 15   6.6   3.6
 34000 -48.8 -55.8  050  38 19   8.3   4.6 | -48.3 -54.9  040  29 15   8.6   4.7
 32000 -43.8 -46.8  040  36 18   8.3   4.5 | -43.2 -45.8  035  29 15   8.5   4.7
 30000 -38.2 -36.8  030  34 17   8.2   4.5 | -37.6 -35.7  030  29 15   8.0   4.4
 29000 -35.8 -32.4  030  33 17   8.2   4.5 | -35.2 -31.4  030  28 14   8.0   4.4
 28000 -33.3 -27.9  030  31 16   8.2   4.5 | -32.8 -27.0  025  27 14   8.1   4.4
 27000 -31.0 -23.8  025  30 16   7.2   4.0 | -30.4 -22.7  025  26 13   7.5   4.1
 26000 -28.9 -20.0  020  29 15   7.2   3.9 | -28.2 -18.8  025  25 13   7.5   4.1
 25000 -26.7 -16.1  015  28 14   7.2   4.0 | -25.9 -14.6  020  24 12   7.5   4.1
 24000 -24.6 -12.3  010  26 13   7.2   4.0 | -23.8 -10.8  020  23 12   6.7   3.7
 23000 -22.4  -8.3  005  24 12   7.2   4.0 | -21.8  -7.2  015  22 11   6.7   3.7
 22000 -20.3  -4.5  360  21 11   7.2   4.0 | -19.7  -3.5  010  20 11   6.7   3.7
 21000 -18.1  -0.6  355  19 10   7.1   3.9 | -17.7   0.1  005  19 10   6.6   3.6
 20000 -16.0   3.2  355  17  9   7.1   3.9 | -15.7   3.7  360  18  9   6.6   3.6
 19500 -14.9   5.2  350  16  8   7.1   3.9 | -14.8   5.4  355  17  9   6.6   3.6
 19000 -13.8   7.2  350  15  8   7.0   3.9 | -13.8   7.2  355  16  8   6.6   3.6
 18500 -12.9   8.8  350  14  7   6.3   3.5 | -12.8   9.0  350  16  8   6.2   3.4
 18000 -11.9  10.6  350  14  7   6.3   3.5 | -11.9  10.6  350  15  8   6.2   3.4
 17500 -10.9  12.4  350  13  7   7.2   3.9 | -10.9  12.4  345  15  8   6.3   3.5
 17000  -9.8  14.4  350  13  6   7.5   4.1 | -10.0  14.0  345  15  7   6.4   3.5
 16500  -8.7  16.3  350  12  6   7.2   4.0 |  -9.0  15.8  345  14  7   6.5   3.6
 16000  -7.7  18.1  350  13  6   5.9   3.2 |  -8.0  17.6  345  14  7   6.8   3.7
 15500  -6.8  19.8  350  13  7   6.0   3.3 |  -7.0  19.4  345  14  7   6.9   3.8
 15000  -6.0  21.2  350  14  7   5.5   3.0 |  -5.6  21.9  340  14  7   6.0   3.3
 14500  -4.8  23.4  345  15  8   5.9   3.2 |  -4.8  23.4  340  14  7   6.1   3.3
 14000  -4.0  24.8  345  15  8   5.9   3.2 |  -3.9  25.0  340  14  7   6.5   3.6
 13500  -3.2  26.2  345  15  8   5.9   3.3 |  -2.9  26.8  345  13  7   6.6   3.6
 13000  -2.1  28.2  345  15  8   8.5   4.6 |  -1.9  28.6  345  12  6   8.3   4.5
 12500  -0.9  30.4  345  15  8   7.1   3.9 |  -0.8  30.6  345  11  6   7.7   4.2
 12000   0.2  32.4  350  16  8   9.1   5.0 |   0.4  32.7  350  10  5   9.8   5.4
 11750   0.9  33.6  350  16  8   8.6   4.7 |   1.1  34.0  350   9  5   9.5   5.2
 11500   1.5  34.7  350  16  8   8.9   4.9 |   1.8  35.2  350   9  5   9.5   5.2
 11250   2.2  36.0  350  17  9   8.3   4.6 |   2.5  36.5  350   9  4  10.1   5.5
 11000   2.8  37.0  350  16  8   8.2   4.5 |   3.3  37.9  350   9  4  10.2   5.6
 10750   3.4  38.1  350  16  8   8.6   4.7 |   4.0  39.2  350   9  4   9.6   5.3
 10500   4.0  39.2  350  16  8   8.9   4.9 |   4.7  40.5  355   8  4  10.0   5.5
 10250   4.6  40.3  355  17  9   7.4   4.0 |   5.5  41.9  355   8  4   8.7   4.8
 10000   5.1  41.2  350  16  8   6.8   3.7 |   6.1  43.0  355   8  4   9.1   5.0
  9750   5.6  42.1  350  15  8   8.3   4.5 |   6.9  44.4  355   8  4  10.8   5.9
  9500   6.2  43.2  350  14  7   8.3   4.5 |   7.7  45.9  355   8  4  10.6   5.8
  9250   6.8  44.2  350  13  7   7.7   4.2 |   8.4  47.1  355   8  4   9.7   5.3
  9000   7.3  45.1  350  12  6   7.2   4.0 |   9.1  48.4  355   8  4   9.2   5.0
  8750   7.9  46.2  345  11  5   8.3   4.6 |   9.8  49.6  355   8  4  10.2   5.6
  8500   8.5  47.3  345   9  5   8.6   4.7 |  10.6  51.1  355   8  4  10.7   5.9
  8250   9.1  48.4  340   8  4   7.8   4.3 |  11.4  52.5  355   8  4  10.6   5.8
  8000   9.6  49.3  335   7  4   7.3   4.0 |  12.2  54.0  355   7  4  11.1   6.1
  7750  10.2  50.4  335   6  3   8.2   4.5 |  13.0  55.4  355   7  4   9.3   5.1
  7500  10.8  51.4  330   5  3   8.6   4.7 |  13.7  56.7  355   7  4  10.4   5.7
  7250  11.3  52.3  325   5  2   7.8   4.3 |  14.6  58.3  355   7  4  14.2   7.8
  7000  11.9  53.4  320   4  2   8.3   4.5 |  15.6  60.1  355   7  3  12.6   6.9
  6750     M     M    M   M  M     M     M |     M     M    M   M  M     M     M

           04/29/2015 at 1500 MDT          |       04/29/2015 at 1800 MDT
                                           |
K index... +5.4  LI... +274.1              | K index... +15.2  LI... +273.6
CAPE... 0.0  CIN... M                      | CAPE... 0.0  CIN... -0.6
                                           |
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 -62.2 -80.0  350  17  9   2.4   1.3 | -62.1 -79.8  330  15  8   2.3   1.3
 45000 -59.1 -74.4  360  20 10  -0.9  -0.5 | -59.1 -74.4  340  20 10  -1.0  -0.5
 40000 -60.5 -76.9  045  22 12  -1.7  -0.9 | -60.6 -77.1  050  14  7  -1.9  -1.0
 38000 -56.9 -70.4  045  24 12   7.3   4.0 | -56.9 -70.4  050  16  8   7.5   4.1
 36000 -52.5 -62.5  035  25 13   7.3   4.0 | -52.4 -62.3  040  18  9   7.5   4.1
 34000 -47.8 -54.0  035  25 13   8.5   4.7 | -47.6 -53.7  040  20 11   8.6   4.7
 32000 -42.6 -44.7  030  25 13   8.5   4.7 | -42.4 -44.3  035  22 11   8.6   4.7
 30000 -37.0 -34.6  030  25 13   8.0   4.4 | -36.8 -34.2  035  23 12   8.0   4.4
 29000 -34.6 -30.3  025  25 13   8.0   4.4 | -34.4 -29.9  030  22 12   8.0   4.4
 28000 -32.2 -26.0  025  25 13   8.0   4.4 | -32.0 -25.6  025  22 11   8.0   4.4
 27000 -29.9 -21.8  025  25 13   7.6   4.2 | -29.7 -21.5  025  22 11   7.5   4.1
 26000 -27.6 -17.7  020  24 12   7.6   4.2 | -27.4 -17.3  020  21 11   7.5   4.1
 25000 -25.3 -13.5  020  23 12   7.6   4.2 | -25.2 -13.4  015  21 11   7.5   4.1
 24000 -23.2  -9.8  015  21 11   6.6   3.6 | -23.0  -9.4  015  20 11   7.2   3.9
 23000 -21.2  -6.2  010  20 11   6.7   3.7 | -20.8  -5.4  010  21 11   7.2   3.9
 22000 -19.2  -2.6  005  20 10   6.6   3.6 | -18.7  -1.7  005  21 11   7.1   3.9
 21000 -17.3   0.9  360  19 10   6.1   3.3 | -16.8   1.8  360  21 11   5.8   3.2
 20000 -15.5   4.1  355  19 10   6.1   3.3 | -15.0   5.0  355  21 11   5.8   3.2
 19500 -14.6   5.7  350  19 10   6.1   3.3 | -14.2   6.4  350  21 11   5.8   3.2
 19000 -13.7   7.3  350  19 10   6.1   3.3 | -13.3   8.1  350  21 11   5.8   3.2
 18500 -12.8   9.0  345  19 10   5.9   3.2 | -12.4   9.7  345  21 11   6.3   3.5
 18000 -11.9  10.6  345  19 10   5.8   3.2 | -11.5  11.3  340  21 11   6.3   3.4
 17500 -11.0  12.2  340  19 10   6.8   3.8 | -10.5  13.1  340  21 11   7.6   4.2
 17000  -9.9  14.2  340  18  9   7.1   3.9 |  -9.4  15.1  335  21 11   8.2   4.5
 16500  -8.8  16.2  335  18  9   7.3   4.0 |  -8.2  17.2  330  21 11   8.4   4.6
 16000  -7.7  18.1  330  18  9   7.7   4.2 |  -7.0  19.4  330  20 10   8.8   4.8
 15500  -6.6  20.1  325  18  9   7.8   4.3 |  -5.7  21.7  330  19 10   9.0   5.0
 15000  -5.0  23.0  325  16  8   7.4   4.0 |  -3.9  25.0  330  16  8   8.1   4.4
 14500  -4.0  24.8  330  14  7   7.3   4.0 |  -2.7  27.1  335  14  7   7.7   4.2
 14000  -3.0  26.6  335  11  6   7.3   4.0 |  -1.8  28.8  345  11  5   5.7   3.1
 13500  -2.0  28.4  345   8  4   7.5   4.1 |  -0.9  30.4  360   8  4   5.7   3.1
 13000  -0.7  30.7  355   7  4  10.0   5.5 |   0.2  32.4  020   6  3   9.3   5.1
 12500   0.7  33.3  360   6  3   8.8   4.8 |   1.6  34.9  040   5  3   7.2   3.9
 12000   2.1  35.8  005   6  3  10.1   5.5 |   2.7  36.9  055   5  3   9.9   5.4
 11750   2.8  37.0  005   6  3   9.7   5.3 |   3.4  38.1  055   5  3   9.4   5.1
 11500   3.5  38.3  005   6  3   9.9   5.4 |   4.1  39.4  060   5  3   9.5   5.2
 11250   4.3  39.7  005   6  3   9.1   5.0 |   4.8  40.6  060   5  3   9.4   5.2
 11000   4.9  40.8  005   6  3   9.5   5.2 |   5.5  41.9  060   5  3   9.6   5.3
 10750   5.7  42.3  010   6  3  10.3   5.7 |   6.2  43.2  065   5  3   9.6   5.3
 10500   6.5  43.7  010   6  3  10.5   5.8 |   7.0  44.6  070   5  3  10.1   5.6
 10250   7.2  45.0  010   6  3   8.5   4.7 |   7.7  45.9  070   5  3   8.1   4.4
 10000   7.8  46.0  010   6  3   8.8   4.8 |   8.2  46.8  075   5  2   8.4   4.6
  9750   8.6  47.5  010   6  3  11.1   6.1 |   9.0  48.2  075   5  2  10.8   6.0
  9500   9.4  48.9  010   6  3  10.7   5.9 |   9.8  49.6  080   5  2  10.4   5.7
  9250  10.2  50.4  010   6  3   9.8   5.4 |  10.5  50.9  080   5  2  10.0   5.5
  9000  10.9  51.6  010   5  3   9.2   5.1 |  11.3  52.3  080   4  2   9.5   5.2
  8750  11.6  52.9  015   5  3  10.4   5.7 |  12.0  53.6  085   4  2  10.2   5.6
  8500  12.4  54.3  015   5  3  10.8   6.0 |  12.8  55.0  085   4  2  10.5   5.8
  8250  13.2  55.8  015   5  3  10.5   5.7 |  13.5  56.3  085   4  2   9.9   5.4
  8000  14.0  57.2  015   5  3  10.8   5.9 |  14.3  57.7  085   4  2   9.7   5.3
  7750  14.7  58.5  015   5  3   9.5   5.2 |  15.0  59.0  085   4  2   9.2   5.1
  7500  15.4  59.7  015   5  3  10.3   5.7 |  15.6  60.1  090   4  2   8.3   4.5
  7250  16.3  61.3  020   5  3  13.3   7.3 |  16.2  61.2  090   4  2   7.8   4.3
  7000  17.3  63.1  020   5  3  12.8   7.0 |  16.7  62.1  090   4  2   7.6   4.1
  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.