Soaring Guidance
Issued by NWS Denver/Boulder, 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 15 16 17 18 19 20 21 22 23
000
UXUS97 KBOU 281351
SRGBOU

Soaring Forecast
National Weather Service Denver/Boulder, Colorado
0751 MDT Friday, August 28, 2015

This forecast is for Friday, August 28, 2015:

If the trigger temperature of 74.3 F/23.5 C is reached...then
   Thermal Soaring Index....................... Excellent
   Maximum rate of lift........................ 829 ft/min (4.2 m/s)
   Maximum height of thermals.................. 15440 ft MSL (10155 ft AGL)

Forecast maximum temperature................... 86.0 F/30.5 C
Time of trigger temperature.................... 1015 MDT
Time of overdevelopment........................ 1500 MDT
Middle/high clouds during soaring window....... None
Surface winds during soaring window............ 20 mph or less
Height of the -3 thermal index................. 12573 ft MSL (7288 ft AGL)
Thermal soaring outlook for Saturday 08/29..... Excellent

Wave Soaring Index............................. Fair
Wave Soaring Index trend (to 1800 MDT)......... Becoming poor
Height of stable layer (12-18K ft MSL)......... 11938 ft MSL (6653 ft AGL)
Weak PVA/NVA (through 1800 MDT)................ Weak NVA
Potential height of wave....................... 19082 ft MSL (13797 ft AGL)
Wave soaring outlook for Saturday 08/29........ Poor

Remarks... Isolated afternoon thunderstorms

Sunrise/Sunset.................... 06:23:32 / 19:38:34 MDT
Total possible sunshine........... 13 hr 15 min 1 sec (795 min 1 sec)
Altitude of sun at 13:00:38 MDT... 59.85 degrees

Upper air data from rawinsonde observation taken on 08/28/2015 at 0600 MDT

Freezing level.................. 15099 ft MSL (9814 ft AGL)
Convective condensation level... 13657 ft MSL (8372 ft AGL)
Lifted condensation level....... 14574 ft MSL (9288 ft AGL)
Lifted index.................... -2.3
K index......................... +21.5

Height  Temperature  Wind  Wind Spd  Lapse Rate  ConvectionT  Thermal  Lift Rate
ft MSL  deg C deg F   Dir   kt  m/s  C/km F/kft  deg C deg F   Index    fpm  m/s
--------------------------------------------------------------------------------
 50000  -64.3 -83.7   275   36   18   5.4   3.0   85.6 186.0    32.4      M    M
 45000  -57.4 -71.3   260   47   24   0.3   0.2   72.6 162.6    26.6      M    M
 40000  -55.0 -67.0   270   63   32   6.1   3.3   53.5 128.2    15.7      M    M
 38000  -51.1 -60.0   270   54   28   7.4   4.0   50.7 123.2    14.2      M    M
 36000  -47.0 -52.6   275   45   23   4.8   2.6   48.1 118.6    12.8      M    M
 34000  -42.0 -43.6   270   45   23   9.1   5.0   47.0 116.5    12.3      M    M
 32000  -36.0 -32.8   275   44   23   7.6   4.2   46.1 115.0    12.0      M    M
 30000  -30.9 -23.6   270   40   21   8.7   4.7   45.3 113.5    11.6      M    M
 29000  -28.3 -18.9   265   40   21   8.7   4.7   44.8 112.7    11.4      M    M
 28000  -25.7 -14.3   275   39   20   8.7   4.8   44.3 111.8    11.2      M    M
 27000  -23.2  -9.8   280   38   20   8.1   4.4   43.9 111.0    10.9      M    M
 26000  -21.5  -6.7   290   38   20   5.8   3.2   42.3 108.1     9.8      M    M
 25000  -19.1  -2.4   295   39   20   7.9   4.3   41.7 107.0     9.4      M    M
 24000  -16.9   1.6   295   39   20   5.9   3.3   40.8 105.4     8.8      M    M
 23000  -15.3   4.5   295   35   18   5.2   2.8   39.1 102.4     7.5      M    M
 22000  -13.7   7.3   290   30   16   5.6   3.1   37.6  99.6     6.2      M    M
 21000  -11.4  11.5   285   26   13   9.7   5.3   36.9  98.4     5.7      M    M
 20000   -8.6  16.5   320   25   13   9.1   5.0   36.7  98.1     5.6      M    M
 19500   -7.3  18.9   325   26   13   8.3   4.6   36.6  97.9     5.5      M    M
 19000   -6.2  20.8   325   26   13   7.7   4.2   36.2  97.2     5.1      M    M
 18500   -5.7  21.7   325   27   14   1.9   1.0   35.1  95.2     4.2      M    M
 18000   -5.1  22.8   325   27   14   4.4   2.4   34.2  93.6     3.3      M    M
 17500   -4.4  24.1   325   28   14   5.4   3.0   33.4  92.1     2.6      M    M
 17000   -3.6  25.5   325   28   14   5.6   3.0   32.7  90.8     1.9      M    M
 16500   -2.8  27.0   325   28   15   5.8   3.2   32.0  89.6     1.3      M    M
 16000   -1.4  29.5   325   29   15   6.4   3.5   31.0  87.9     0.5      M    M
 15500   -0.5  31.1   320   30   15   7.2   4.0   30.5  86.9    -0.1    824  4.2
 15000    0.1  32.2   320   30   15   4.1   2.3   29.7  85.5    -0.9    791  4.0
 14500    1.1  34.0   325   28   15   7.7   4.2   29.3  84.7    -1.4    746  3.8
 14000    2.3  36.1   325   27   14   7.6   4.2   28.9  84.1    -1.7    698  3.5
 13500    3.4  38.1   325   25   13   7.6   4.2   28.6  83.4    -2.1    650  3.3
 13000    4.5  40.1   320   24   12   6.9   3.8   28.2  82.8    -2.4    601  3.1
 12500    5.1  41.2   320   22   11   2.9   1.6   27.3  81.2    -3.3    569  2.9
 12000    5.4  41.7   315   21   11   2.8   1.6   26.3  79.3    -4.4    543  2.8
 11500    6.4  43.5   315   19   10   9.9   5.4   25.8  78.4    -5.0    501  2.5
 11000    7.7  45.9   310   16    8   9.3   5.1   25.7  78.2    -5.1    446  2.3
 10500    9.1  48.4   310   14    7   9.9   5.4   25.6  78.1    -5.2    390  2.0
 10250    9.8  49.6   310   13    7   8.5   4.7   25.6  78.1    -5.3    362  1.8
 10000   10.3  50.5   310   12    6   6.6   3.6   25.4  77.7    -5.6    340  1.7
  9750   10.7  51.3   310   11    5   7.1   3.9   25.2  77.3    -5.8    318  1.6
  9500   11.2  52.2   310    9    5   7.0   3.8   25.0  76.9    -6.1    296  1.5
  9250   11.7  53.1   305    8    4   7.0   3.9   24.8  76.6    -6.3    273  1.4
  9000   12.2  54.0   305    7    4   7.0   3.8   24.6  76.2    -6.5    251  1.3
  8750   12.7  54.9   310    6    3   7.3   4.0   24.3  75.8    -6.8    229  1.2
  8500   13.3  55.9   320    5    3   8.3   4.6   24.2  75.5    -7.0    205  1.0
  8250   13.9  57.0   330    5    2   8.8   4.8   24.1  75.4    -7.1    177  0.9
  8000   14.6  58.3   340    4    2   8.7   4.8   24.0  75.3    -7.1    150  0.8
  7750   15.3  59.5   350    5    3   8.7   4.8   24.0  75.1    -7.2    123  0.6
  7500   15.9  60.6   355    6    3   8.9   4.9   23.9  75.0    -7.3     95  0.5
  7250   16.6  61.9   360    8    4   8.0   4.4   23.8  74.8    -7.4     68  0.3
  7000   17.1  62.8   005    9    5   4.0   2.2   23.5  74.4    -7.7     47  0.2
  6750   17.2  63.0   005    9    4   2.1   1.1   23.0  73.3    -8.3     36  0.2
  6500   17.3  63.1   005    8    4   2.3   1.2   22.4  72.3    -8.9     24  0.1
  6250   17.5  63.5   010    8    4   3.5   1.9   21.9  71.3    -9.5     13  0.1
  6000   17.6  63.7   010    7    4  -2.1  -1.1   21.3  70.3   -10.1      2  0.0
  5750   17.1  62.8   360    6    3  -2.4  -1.3   20.2  68.4   -11.4      9  0.0
  5500   17.4  63.3   350    5    2  10.2   5.6   19.8  67.6   -11.9      M    M

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

           08/28/2015 at 0900 MDT          |       08/28/2015 at 1200 MDT
                                           |
K index... +18.8  LI... -1.0               | K index... +21.3  LI... -0.5
CAPE... +165.3  CIN... -43.8               | CAPE... +89.9  CIN... -36.6
                                           |
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 -62.8 -81.0  265  30 15   2.1   1.1 | -62.8 -81.0  275  26 13   1.5   0.8
 45000 -59.3 -74.7  270  42 22   2.5   1.4 | -60.0 -76.0  275  35 18   2.5   1.4
 40000 -55.0 -67.0  275  52 27   6.9   3.8 | -55.6 -68.1  290  38 20   7.2   3.9
 38000 -50.9 -59.6  275  46 24   6.8   3.8 | -51.3 -60.3  290  33 17   7.1   3.9
 36000 -46.8 -52.2  275  41 21   6.8   3.7 | -47.0 -52.6  295  29 15   7.1   3.9
 34000 -42.2 -44.0  280  38 20   7.8   4.3 | -42.3 -44.1  300  26 14   8.1   4.4
 32000 -37.5 -35.5  280  36 19   7.9   4.3 | -37.4 -35.3  305  25 13   8.1   4.4
 30000 -32.3 -26.1  285  35 18   7.7   4.2 | -32.3 -26.1  305  24 12   7.4   4.1
 29000 -30.0 -22.0  285  35 18   7.7   4.2 | -30.1 -22.2  310  23 12   7.4   4.1
 28000 -27.7 -17.9  290  35 18   8.0   4.4 | -27.9 -18.2  310  23 12   7.5   4.1
 27000 -25.3 -13.5  295  33 17   8.1   4.5 | -25.6 -14.1  310  23 12   7.5   4.1
 26000 -22.8  -9.0  300  31 16   8.1   4.5 | -23.4 -10.1  315  23 12   7.5   4.1
 25000 -20.4  -4.7  305  30 15   8.0   4.4 | -21.2  -6.2  315  22 12   7.5   4.1
 24000 -18.2  -0.8  305  27 14   7.3   4.0 | -18.9  -2.0  320  22 11   7.5   4.1
 23000 -16.0   3.2  310  24 12   7.3   4.0 | -16.7   1.9  320  22 11   7.5   4.1
 22000 -13.9   7.0  315  21 11   7.1   3.9 | -14.5   5.9  320  22 11   7.3   4.0
 21000 -12.0  10.4  320  20 10   6.4   3.5 | -12.5   9.5  320  21 11   6.9   3.8
 20000 -10.1  13.8  325  18  9   6.5   3.6 | -10.4  13.3  320  19 10   6.9   3.8
 19500  -9.2  15.4  325  18  9   6.6   3.6 |  -9.4  15.1  320  19 10   7.1   3.9
 19000  -8.2  17.2  330  18  9   6.2   3.4 |  -8.5  16.7  320  18  9   5.6   3.1
 18500  -7.3  18.9  335  18  9   6.2   3.4 |  -7.7  18.1  325  18  9   5.8   3.2
 18000  -6.3  20.7  340  18 10   6.0   3.3 |  -6.9  19.6  325  19 10   6.0   3.3
 17500  -5.5  22.1  345  19 10   5.8   3.2 |  -6.0  21.2  330  18  9   6.2   3.4
 17000  -4.6  23.7  350  19 10   5.7   3.2 |  -5.1  22.8  335  18  9   6.2   3.4
 16500  -3.8  25.2  350  20 10   6.5   3.5 |  -4.1  24.6  340  18  9   7.4   4.1
 16000  -2.4  27.7  355  22 11   6.5   3.6 |  -2.5  27.5  345  18  9   7.3   4.0
 15500  -1.4  29.5  355  22 12   7.6   4.2 |  -1.4  29.5  345  18  9   7.5   4.1
 15000  -0.3  31.5  355  23 12   7.6   4.2 |  -0.3  31.5  350  18  9   7.5   4.1
 14500   0.8  33.4  355  23 12   7.0   3.9 |   0.8  33.4  350  18  9   7.6   4.2
 14000   1.8  35.2  355  22 12   7.0   3.9 |   2.0  35.6  350  17  9   7.6   4.2
 13500   2.7  36.9  355  21 11   6.8   3.7 |   3.1  37.6  350  17  9   7.5   4.1
 13000   3.7  38.7  360  20 10   6.8   3.7 |   4.2  39.6  350  16  8   7.5   4.1
 12500   4.7  40.5  360  19 10   7.1   3.9 |   5.3  41.5  350  15  8   7.7   4.2
 12000   5.8  42.4  005  18  9   7.3   4.0 |   6.4  43.5  355  14  7   7.8   4.3
 11500   6.8  44.2  005  16  8   7.7   4.2 |   7.6  45.7  355  12  6   8.2   4.5
 11000   8.0  46.4  005  15  8   7.9   4.3 |   8.8  47.8  355  11  5   8.2   4.5
 10500   9.2  48.6  005  15  8   4.6   2.5 |  10.0  50.0  355   9  5   3.1   1.7
 10250   9.4  48.9  005  14  7   5.4   3.0 |  10.0  50.0  355   9  4   4.7   2.6
 10000  10.1  50.2  005  14  7  11.7   6.4 |  10.8  51.4  355   8  4  12.7   6.9
  9750  10.9  51.6  005  14  7  11.8   6.5 |  11.6  52.9  355   7  3  11.5   6.3
  9500  11.7  53.1  005  13  7   9.0   5.0 |  12.4  54.3  350   6  3   9.3   5.1
  9250  12.2  54.0  360  13  7   6.2   3.4 |  12.9  55.2  345   5  3   7.4   4.1
  9000  12.8  55.0  360  13  7   9.6   5.3 |  13.5  56.3  345   5  3  10.4   5.7
  8750  13.6  56.5  355  13  6  11.3   6.2 |  14.3  57.7  340   5  3  11.5   6.3
  8500  14.3  57.7  355  12  6   8.8   4.8 |  15.1  59.2  340   5  2   9.9   5.5
  8250  14.9  58.8  355  12  6   7.5   4.1 |  15.8  60.4  340   5  2   9.2   5.0
  8000  15.4  59.7  350  13  6   7.9   4.4 |  16.5  61.7  340   5  2  10.0   5.5
  7750  16.0  60.8  350  13  7   7.9   4.3 |  17.3  63.1  335   4  2  10.6   5.8
  7500  16.6  61.9  345  13  7   7.8   4.3 |  18.0  64.4  335   4  2  10.1   5.5
  7250  17.1  62.8  345  12  6   7.9   4.3 |  18.8  65.8  335   4  2  10.3   5.6
  7000  17.6  63.7  340  12  6   7.5   4.1 |  19.5  67.1  335   4  2   9.4   5.2
  6750  18.1  64.6  340  12  6   7.6   4.2 |  20.2  68.4  330   4  2   9.6   5.2
  6500  18.7  65.7  335  10  5   8.1   4.5 |  21.0  69.8  330   4  2  10.7   5.9
  6250  19.3  66.7  325   9  5   8.0   4.4 |  21.8  71.2  330   4  2  10.0   5.5
  6000  19.8  67.6  315   8  4   8.3   4.6 |  22.6  72.7  330   4  2  11.5   6.3
  5750  20.5  68.9  310   7  4  12.1   6.6 |  23.6  74.5  325   4  2  17.8   9.8
  5500  21.6  70.9  305   6  3  17.6   9.6 |  25.2  77.4  330   4  2  24.0  13.2

           08/28/2015 at 1500 MDT          |       08/28/2015 at 1800 MDT
                                           |
K index... +20.1  LI... -0.2               | K index... +26.0  LI... -1.2
CAPE... +26.9  CIN... -24.3                | CAPE... +45.8  CIN... -40.4
                                           |
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 -63.3 -81.9  270  22 11   1.4   0.8 | -63.2 -81.8  270  22 11   1.2   0.7
 45000 -60.9 -77.6  280  27 14   1.9   1.1 | -60.9 -77.6  285  29 15   2.0   1.1
 40000 -57.0 -70.6  310  27 14   8.3   4.6 | -57.0 -70.6  305  31 16   7.9   4.3
 38000 -51.9 -61.4  315  27 14   8.5   4.7 | -52.1 -61.8  310  29 15   8.1   4.4
 36000 -46.8 -52.2  320  27 14   8.5   4.7 | -47.3 -53.1  320  29 15   8.0   4.4
 34000 -41.7 -43.1  325  28 15   8.6   4.7 | -42.0 -43.6  325  28 14   8.9   4.9
 32000 -36.6 -33.9  330  29 15   8.5   4.7 | -36.6 -33.9  330  27 14   8.9   4.9
 30000 -31.5 -24.7  330  25 13   7.3   4.0 | -31.0 -23.8  330  24 12   8.2   4.5
 29000 -29.3 -20.7  325  23 12   7.3   4.0 | -28.6 -19.5  330  22 12   8.2   4.5
 28000 -27.1 -16.8  325  20 10   7.1   3.9 | -26.2 -15.2  330  21 11   6.9   3.8
 27000 -24.9 -12.8  330  19 10   7.1   3.9 | -24.1 -11.4  330  18  9   6.8   3.8
 26000 -22.8  -9.0  330  17  9   7.2   3.9 | -22.1  -7.8  325  16  8   6.9   3.8
 25000 -20.7  -5.3  330  15  8   7.3   4.0 | -20.1  -4.2  320  14  7   6.8   3.8
 24000 -18.5  -1.3  335  16  8   7.4   4.1 | -18.1  -0.6  325  14  7   6.7   3.7
 23000 -16.3   2.7  335  16  8   7.5   4.1 | -16.1   3.0  330  14  7   6.8   3.7
 22000 -14.1   6.6  335  16  8   7.2   4.0 | -14.1   6.6  335  15  8   6.7   3.7
 21000 -12.1  10.2  335  18  9   6.8   3.7 | -12.2  10.0  335  17  9   6.5   3.6
 20000 -10.0  14.0  335  19 10   6.8   3.7 | -10.3  13.5  335  19 10   6.6   3.6
 19500  -9.0  15.8  335  20 10   6.8   3.7 |  -9.3  15.3  335  20 10   6.5   3.6
 19000  -8.0  17.6  335  20 11   6.8   3.7 |  -8.3  17.1  335  20 10   7.4   4.1
 18500  -7.0  19.4  335  21 11   6.8   3.7 |  -7.3  18.9  335  19 10   7.4   4.1
 18000  -6.0  21.2  335  22 11   6.8   3.7 |  -6.3  20.7  330  19 10   7.4   4.0
 17500  -5.0  23.0  335  22 11   6.8   3.8 |  -5.2  22.6  330  18  9   7.3   4.0
 17000  -4.0  24.8  335  22 11   6.9   3.8 |  -4.2  24.4  330  17  9   7.3   4.0
 16500  -3.0  26.6  340  21 11   6.9   3.8 |  -3.1  26.4  330  17  9   7.6   4.2
 16000  -1.5  29.3  340  21 11   7.1   3.9 |  -1.4  29.5  330  16  8   7.7   4.2
 15500  -0.4  31.3  340  21 11   8.1   4.4 |  -0.2  31.6  330  16  8   8.4   4.6
 15000   0.8  33.4  345  20 10   8.1   4.4 |   1.0  33.8  335  15  8   8.3   4.6
 14500   1.9  35.4  345  19 10   7.8   4.3 |   2.3  36.1  335  15  7   8.7   4.7
 14000   3.1  37.6  345  18  9   7.9   4.3 |   3.5  38.3  340  13  7   8.7   4.8
 13500   4.2  39.6  345  17  9   8.3   4.5 |   4.8  40.6  345  12  6   8.0   4.4
 13000   5.4  41.7  350  15  8   8.4   4.6 |   6.0  42.8  345  11  6   7.9   4.3
 12500   6.6  43.9  350  13  7   7.8   4.3 |   7.2  45.0  350  10  5   8.3   4.6
 12000   7.7  45.9  350  11  6   7.5   4.1 |   8.4  47.1  355   9  5   8.5   4.7
 11500   8.7  47.7  355   9  5   8.2   4.5 |   9.7  49.5  355   8  4   8.6   4.7
 11000  10.0  50.0  355   8  4   8.4   4.6 |  10.9  51.6  355   7  4   8.4   4.6
 10500  11.2  52.2  355   6  3   3.7   2.0 |  12.2  54.0  355   7  3   3.4   1.9
 10250  11.3  52.3  355   6  3   5.7   3.1 |  12.3  54.1  355   7  3   4.9   2.7
 10000  12.1  53.8  355   6  3  12.9   7.1 |  13.1  55.6  355   6  3  12.5   6.8
  9750  13.0  55.4  355   5  3  11.2   6.1 |  13.9  57.0  355   6  3  10.9   6.0
  9500  13.8  56.8  350   5  3   9.3   5.1 |  14.6  58.3  355   6  3   9.0   5.0
  9250  14.3  57.7  350   5  3   7.6   4.2 |  15.2  59.4  355   5  3   7.3   4.0
  9000  15.0  59.0  350   5  3  10.6   5.8 |  15.8  60.4  350   5  3   9.7   5.3
  8750  15.9  60.6  350   5  3  11.5   6.3 |  16.5  61.7  345   5  3  10.4   5.7
  8500  16.7  62.1  350   5  2  10.3   5.7 |  17.3  63.1  345   5  3   9.8   5.4
  8250  17.4  63.3  345   5  2   9.8   5.4 |  18.0  64.4  340   5  3   9.5   5.2
  8000  18.2  64.8  345   5  2  10.1   5.6 |  18.7  65.7  340   5  3   9.9   5.4
  7750  18.9  66.0  345   5  2  10.3   5.6 |  19.5  67.1  340   5  3  10.2   5.6
  7500  19.7  67.5  345   5  2  10.1   5.5 |  20.2  68.4  335   5  3  10.0   5.5
  7250  20.4  68.7  340   5  2  10.0   5.5 |  21.0  69.8  335   5  3  10.1   5.5
  7000  21.2  70.2  340   5  2  10.3   5.7 |  21.7  71.1  335   5  3   9.5   5.2
  6750  22.0  71.6  340   5  2  10.3   5.7 |  22.4  72.3  330   5  3   9.4   5.1
  6500  22.7  72.9  335   5  2  10.1   5.5 |  23.1  73.6  330   5  3  10.3   5.6
  6250  23.5  74.3  335   5  2   9.8   5.4 |  23.9  75.0  330   5  3  10.2   5.6
  6000  24.2  75.6  335   5  2  10.8   6.0 |  24.6  76.3  330   5  3  10.7   5.9
  5750  25.2  77.4  335   4  2  17.7   9.7 |  25.6  78.1  325   5  3  13.3   7.3
  5500  26.9  80.4  335   4  2  25.8  14.1 |  26.6  79.9  330   5  3  15.9   8.7
________________________________________________________________________________

This product is issued twice per day, once by approximately 0630 MST/0730 MDT
(1330 UTC) and again by approximately 1830 MST/1930 MDT (0130 UTC).  It is not
continuously monitored nor updated after its initial issuance.

The information contained herein is based on rawinsonde observation and/or
numerical weather prediction model data taken near the old Stapleton
Airport site in Denver, Colorado at

                   North Latitude:  39 deg 46 min 5.016 sec
                   West Longitude: 104 deg 52 min 9.984 sec
                   Elevation: 5285 feet (1611 meters)

and may not be representative of other areas along the Front Range of the
Colorado Rocky Mountains.  Note that some elevations in numerical weather
prediction models differ from actual station elevations, which can lead to
data which appear to be below ground.  Erroneous data such as these should
not be used.

The content and format of this report as well as the issuance times are subject
to change without prior notice.  Comments and suggestions are welcome and should
be directed to one of the addresses or phone numbers shown at the bottom of this
page.  To expedite a response to comments, be sure to mention your interest in
the soaring forecast.

DEFINITIONS:

CAPE (Convective Available Potential Energy) - An integrated measure of the
     energy available for convective development, also known as the positive
     area on a thermodynamic diagram.  Units are Joules per kilogram.  Larger
     values are indicative of greater instability and the possibility of
     stronger convective activity, including thunderstorms.  Values around or
     greater than 1000 suggest the possibility of severe weather should
     convective activity develop.

CIN (Convective Inhibition) - An integrated measure of the amount of energy
     needed to initiate convective activity, also known as the negative area on
     a thermodynamic diagram.  Units are Joules per kilogram.  The more negative
     this number, the more energy is required to initiate convection.  This
     inhibitive energy can be overcome through surface heating, cooling aloft,
     lifting mechanisms (orographic, frontal, gravity waves, etc.)

Convective Condensation Level - The height to which an air parcel possessing the
     average saturation mixing ratio in the lowest 4000 feet of the airmass,
     if heated sufficiently from below, will rise dry adiabatically until it
     just becomes saturated.  It estimates the base of cumulus clouds that are
     produced by surface heating only.

Convection Temperature (ConvectionT) - The surface temperature required to make
     the airmass dry adiabatic up to the given level.  It can be considered a
     "trigger temperature" for that level.

Freezing Level - The height where the temperature is zero degrees Celsius.

Height of Stable Layer - The height (between 12,000 and 18,000 feet above
     mean sea level) where the smallest lapse rate exists.  The location and
     existence of this feature is important in the generation of mountain
     waves.

K Index - A measure of stability which combines the temperature difference
     between approximately 5,000 and 18,000 feet above the surface, the amount
     of moisture at approximately 5,000 feet above the surface, and a measure
     of the dryness at approximately 10,000 feet above the surface.  Larger
     positive numbers indicate more instability and a greater likelihood of
     thunderstorm development.  One interpretation of K index values regarding
     soaring in the western United States is given in WMO Technical Note 158
     and is reproduced in the following table:

          below -10    no or weak thermals
           -10 to 5    dry thermals or 1/8 cumulus with moderate thermals
            5 to 15    good soaring conditions
           15 to 20    good soaring conditions with occasional showers
           20 to 30    excellent soaring conditions, but increasing
                       probability of showers and thunderstorms
           above 30    more than 60 percent probability of thunderstorms

Lapse Rate - The change with height of the temperature. Negative values indicate
     inversions.

Lifted Condensation Level - The height to which an air parcel possessing the
     average dew point in the lowest 4000 feet of the airmass and the forecast
     maximum temperature must be lifted dry adiabatically to attain saturation.

Lifted Index (LI) - The difference between the environmental temperature at a
     level approximately 18,000 feet above the surface and the temperature of
     an air parcel lifted dry adiabatically from the surface to its lifted
     condensation level and then pseudoadiabatically thereafter to this same
     level.  The parcel`s initial temperature is the forecast maximum
     temperature and its dew point is the average dew point in the lowest 4000
     feet of the airmass.  Negative values are indicative of instability with
     positive values showing stable conditions.

Lift Rate - An experimental estimate of the strength of thermals.  It is
     computed the same way as the maximum rate of lift but uses the actual
     level rather than the maximum height of thermals in the calculation.
     Also, none of the empirical adjustments based on cloudiness and K-index
     are applied to these calculations.

Maximum Height of Thermals - The height where the dry adiabat through the
     forecast maximum temperature intersects the environmental temperature.

Maximum Rate of Lift - An estimate of the maximum strength of thermals.  It
     is computed from an empirical formula which combines the expected maximum
     height of thermals with the difference in the environmental temperatures
     between the maximum height of thermals and the temperature 4,000 feet
     above the ground.  After this computation, further empirical adjustments
     are made based on the value of the K-index and the amount and opacity of
     middle and high level cloudiness expected between the time of trigger
     temperature and the time of overdevelopment.

Middle/High Clouds - The amount and opacity of middle (altostratus, altocumulus)
     or high (cirrus, cirrostratus, cirrocumulus) clouds.  Broken means that
     between 60% and 90% of the sky is covered by the cloud, with overcast
     conditions occurring when more than 90% of the sky is covered by the cloud.
     Thin implies that the clouds are predominantly transparent, meaning that
     some sunlight is reaching the ground, in contrast to opaque which suggests
     that little sunlight is reaching the ground.

Potential Height of Wave - The minimum of the following two heights:
     1. Level above the height of stable layer (or 14,000 feet if none exists)
        where the wind direction changes by 30 degrees or more
     2. Level above the height of stable layer (or 14,000 feet if none exists)
        where the wind speed no longer increases with height

PVA/NVA - Positive vorticity advection (PVA)/negative vorticity advection (NVA)
     on the 500 millibar isobaric surface (approximately 18,000 feet above mean
     sea level).  Weak PVA has been shown to assist in mountain wave soaring.

Soaring Window - The time between the time the trigger temperature is reached
                 and the time of overdevelopment.

Thermal Index - The difference between the environmental temperature and the
     temperature at a particular level determined by following the dry adiabat
     through the forecast maximum temperature up to that level.  Negative values
     are indicative of thermal lift.

Thermal Soaring Index - An adjective rating (for sailplanes) based on the
     computed maximum rate of lift, and the wind speed and middle and high
     cloud cover expected during the soaring window (the time of the trigger
     temperature and the time of overdevelopment) according to the following:

                 Maximum rate of lift        Adjective Rating
                      >= 800 fpm                 Excellent
                 >= 400 and < 800 fpm              Good
                 >= 200 and < 400 fpm              Fair
                       < 200 fpm                   Poor

Time of Overdevelopment - The time one or more of the following phenomena,
     which essentially shut off thermal lift, is expected to occur:
     1. formation of broken to overcast convective cloud cover
     2. formation of scattered to numerous downbursts
     3. initiation of widespread precipitation

Time of Trigger Temperature - The time the surface temperature is expected to
     reach the trigger temperature.

Trigger Temperature - The surface temperature required to make the first 4000
     feet of the atmosphere dry adiabatic.

Wave Soaring Index - An empirical, adjective rating (for sailplanes) which
     attempts to combine a variety of phenomena important in mountain wave
     soaring into a single index number.  Objective points are assigned to
     these phenomena: wind speed and direction at 14,000 ft MSL, the static
     stability in the 12,000-18,000 ft MSL layer, the wind speed gradient above
     the stable layer, jet stream location and frontal and upper trough
     movements.

042613


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