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
000
UXUS97 KBOU 120021
SRGBOU

Soaring Forecast
National Weather Service Denver/Boulder, Colorado
1821 MDT Friday, April 11, 2014

This forecast is for Saturday, April 12, 2014:

If the trigger temperature of 68.2 F/20.1 C is reached...then
   Thermal Soaring Index....................... Excellent
   Maximum rate of lift........................ 1034 ft/min (5.3 m/s)
   Maximum height of thermals.................. 17086 ft MSL (11799 ft AGL)

Forecast maximum temperature................... 73.0 F/23.2 C
Time of trigger temperature.................... 1030 MDT
Time of overdevelopment........................ None
Middle/high clouds during soaring window....... Overcast thin high
Surface winds during soaring window............ 20 mph or less
Height of the -3 thermal index................. 8297 ft MSL (3009 ft AGL)
Thermal soaring outlook for Sunday 04/13....... Poor

Wave Soaring Index............................. Fair
Wave Soaring Index trend (to 1800 MDT)......... Becoming poor by 1500.
Height of stable layer (12-18K ft MSL)......... None
Weak PVA/NVA (through 1800 MDT)................ Weak PVA
Potential height of wave....................... 30628 ft MSL (25341 ft AGL)
Wave soaring outlook for Sunday 04/13.......... Poor

Remarks...

Sunrise/Sunset.................... 06:26:25 / 19:33:44 MDT
Total possible sunshine........... 13 hr 7 min 19 sec (787 min 19 sec)
Altitude of sun at 13:00:14 MDT... 59.10 degrees

Upper air data from numerical model forecast valid on 04/12/2014 at 0600 MDT

Freezing level.................. 12369 ft MSL (7082 ft AGL)
Convective condensation level... 17203 ft MSL (11916 ft AGL)
Lifted condensation level....... 17259 ft MSL (11972 ft AGL)
Lifted index.................... -1.4
K index......................... +13.9

Height  Temperature  Wind  Wind Spd  Lapse Rate  ConvectionT  Thermal  Lift Rate
ft MSL  deg C deg F   Dir   kt  m/s  C/km F/kft  deg C deg F   Index    fpm  m/s
--------------------------------------------------------------------------------
 50000  -60.2 -76.4   275   33   17   1.1   0.6      M     M       M      M    M
 45000  -58.4 -73.1   275   40   21  -0.6  -0.3      M     M       M      M    M
 40000  -60.2 -76.4   265   38   19  -1.2  -0.7      M     M       M      M    M
 38000  -59.0 -74.2   260   36   19   4.9   2.7      M     M       M      M    M
 36000  -56.0 -68.8   255   34   17   4.9   2.7      M     M       M      M    M
 34000  -52.7 -62.9   255   33   17   8.2   4.5      M     M       M      M    M
 32000  -47.8 -54.0   255   38   20   8.1   4.5      M     M       M      M    M
 30000  -42.5 -44.5   260   42   21   7.3   4.0   32.6  90.8     7.4      M    M
 29000  -40.3 -40.5   260   41   21   7.3   4.0   31.6  88.9     6.7      M    M
 28000  -38.2 -36.8   265   41   21   7.3   4.0   30.7  87.3     6.1      M    M
 27000  -36.0 -32.8   265   40   21   6.8   3.7   29.8  85.7     5.5      M    M
 26000  -34.0 -29.2   265   37   19   6.7   3.7   28.6  83.4     4.5      M    M
 25000  -32.0 -25.6   265   35   18   6.7   3.7   27.4  81.4     3.7      M    M
 24000  -30.0 -22.0   260   32   16   7.7   4.2   26.5  79.6     2.9      M    M
 23000  -27.5 -17.5   260   30   15   8.4   4.6   25.9  78.5     2.4      M    M
 22000  -25.0 -13.0   255   28   14   8.4   4.6   25.4  77.7     2.1      M    M
 21000  -22.5  -8.5   255   26   14   8.3   4.5   25.0  76.9     1.7      M    M
 20000  -20.0  -4.0   255   26   13   8.3   4.5   24.4  75.8     1.2      M    M
 19500  -18.8  -1.8   255   26   13   8.3   4.5   24.1  75.4     1.0      M    M
 19000  -17.5   0.5   255   26   13   8.3   4.5   23.9  75.0     0.8      M    M
 18500  -16.3   2.7   255   26   13   8.3   4.6   23.7  74.6     0.6      M    M
 18000  -15.0   5.0   260   26   13   8.3   4.6   23.4  74.1     0.4      M    M
 17500  -13.8   7.2   260   26   13   8.4   4.6   23.2  73.7     0.2      M    M
 17000  -12.5   9.5   265   26   13   9.0   4.9   23.0  73.4     0.0      M    M
 16500  -11.2  11.8   265   26   14   9.0   4.9   22.9  73.1    -0.1   1081  5.5
 16000   -9.8  14.4   270   27   14   8.9   4.9   22.7  72.9    -0.3   1026  5.2
 15500   -8.5  16.7   270   27   14   8.9   4.9   22.6  72.6    -0.4    972  4.9
 15000   -6.6  20.1   275   27   14   8.5   4.7   22.3  72.2    -0.7    892  4.5
 14500   -5.3  22.5   275   27   14   8.5   4.7   22.1  71.8    -0.9    839  4.3
 14000   -4.0  24.8   280   26   13   9.1   5.0   22.0  71.5    -1.0    785  4.0
 13500   -2.7  27.1   280   25   13   9.1   5.0   21.9  71.3    -1.2    730  3.7
 13000   -1.4  29.5   280   23   12   8.5   4.7   21.7  71.1    -1.3    676  3.4
 12500   -0.1  31.8   280   22   11   8.3   4.6   21.5  70.7    -1.5    624  3.2
 12000    1.1  34.0   280   20   10   8.6   4.7   21.3  70.3    -1.8    572  2.9
 11500    2.4  36.3   280   18    9   8.8   4.8   21.1  70.0    -2.0    518  2.6
 11000    3.7  38.7   285   16    8   8.3   4.5   21.0  69.7    -2.1    465  2.4
 10500    4.9  40.8   280   14    7   7.2   3.9   20.7  69.2    -2.4    414  2.1
 10250    5.5  41.9   280   14    7  11.1   6.1   20.6  69.0    -2.5    389  2.0
 10000    6.5  43.7   280   13    7  11.6   6.4   20.8  69.5    -2.3    352  1.8
  9750    7.1  44.8   280   12    6   8.0   4.4   20.7  69.3    -2.4    325  1.7
  9500    7.8  46.0   280   12    6   9.0   4.9   20.6  69.2    -2.5    299  1.5
  9250    8.4  47.1   280   11    6   8.5   4.7   20.6  69.0    -2.6    272  1.4
  9000    9.0  48.2   280   10    5   8.3   4.5   20.5  68.8    -2.7    246  1.2
  8750    9.7  49.5   280   10    5   8.3   4.5   20.3  68.6    -2.8    220  1.1
  8500   10.3  50.5   285   10    5   8.2   4.5   20.2  68.4    -2.9    194  1.0
  8250   10.9  51.6   285   10    5   8.6   4.7   20.1  68.2    -3.0    168  0.9
  8000   11.5  52.7   290   10    5   7.9   4.4   20.0  68.0    -3.1    142  0.7
  7750   12.0  53.6   290    9    5   6.2   3.4   19.8  67.7    -3.4    119  0.6
  7500   12.5  54.5   295    9    5   6.0   3.3   19.5  67.1    -3.6     98  0.5
  7250   12.9  55.2   295    9    4   5.8   3.2   19.2  66.6    -3.9     77  0.4
  7000   13.3  55.9   300    9    4   4.9   2.7   18.9  66.0    -4.3     58  0.3
  6750   13.7  56.7   300    8    4   4.0   2.2   18.5  65.3    -4.7     41  0.2
  6500   13.8  56.8   300    8    4   0.8   0.4   18.0  64.3    -5.2     28  0.1
  6250   13.5  56.3   290    7    4 -12.0  -6.6   16.9  62.4    -6.3     31  0.2
  6000   12.1  53.8   270    7    3 -18.9 -10.4   14.8  58.7    -8.4     64  0.3
  5750   10.6  51.1   250    7    4 -25.7 -14.1   12.6  54.6   -10.7    103  0.5
  5500    7.7  45.9   230   10    5 -51.5 -28.3    9.0  48.2   -14.4    183  0.9

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

           04/12/2014 at 0900 MDT          |       04/12/2014 at 1200 MDT
                                           |
K index... +15.1  LI... +0.6               | K index... +14.6  LI... -1.4
CAPE... 0.0  CIN... M                      | CAPE... +66.7  CIN... -75.7
                                           |
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 -60.3 -76.5  275  37 19   1.7   0.9 | -60.1 -76.2  265  38 19   1.2   0.6
 45000 -57.6 -71.7  275  38 20  -0.0  -0.0 | -58.3 -72.9  260  39 20   0.0   0.0
 40000 -58.6 -73.5  265  45 23  -0.6  -0.3 | -59.2 -74.6  250  54 28  -0.6  -0.3
 38000 -57.8 -72.0  260  46 24   2.9   1.6 | -58.4 -73.1  250  54 28   3.1   1.7
 36000 -56.1 -69.0  260  45 23   2.9   1.6 | -56.6 -69.9  245  49 25   3.1   1.7
 34000 -53.8 -64.8  260  45 23   8.6   4.7 | -54.2 -65.6  245  44 23   8.6   4.7
 32000 -48.9 -56.0  265  46 24   8.2   4.5 | -49.3 -56.7  245  41 21   8.2   4.5
 30000 -43.4 -46.1  265  45 23   8.1   4.4 | -43.7 -46.7  240  38 20   9.1   5.0
 29000 -41.0 -41.8  265  41 21   8.1   4.4 | -41.0 -41.8  240  39 20   9.1   5.0
 28000 -38.6 -37.5  265  36 19   8.1   4.4 | -38.2 -36.8  245  40 20   9.1   5.0
 27000 -36.2 -33.2  260  32 17   7.1   3.9 | -35.6 -32.1  245  40 20   7.5   4.1
 26000 -34.2 -29.6  255  30 15   6.9   3.8 | -33.5 -28.3  245  37 19   7.1   3.9
 25000 -32.1 -25.8  250  28 14   6.9   3.8 | -31.4 -24.5  245  34 17   7.1   3.9
 24000 -30.0 -22.0  240  27 14   7.2   4.0 | -29.3 -20.7  245  31 16   6.8   3.7
 23000 -27.8 -18.0  245  26 13   7.5   4.1 | -27.4 -17.3  240  27 14   6.4   3.5
 22000 -25.6 -14.1  245  26 13   7.5   4.1 | -25.5 -13.9  235  24 12   6.4   3.5
 21000 -23.3  -9.9  250  25 13   8.0   4.4 | -23.5 -10.3  230  21 11   7.4   4.0
 20000 -20.9  -5.6  260  23 12   8.1   4.4 | -21.3  -6.3  235  18  9   7.6   4.1
 19500 -19.7  -3.5  260  23 12   8.1   4.4 | -20.2  -4.4  235  16  8   7.6   4.1
 19000 -18.5  -1.3  265  22 11   8.1   4.4 | -19.0  -2.2  240  15  8   7.6   4.2
 18500 -17.3   0.9  270  22 11   8.4   4.6 | -17.9  -0.2  245  13  7   8.0   4.4
 18000 -16.0   3.2  270  21 11   8.6   4.7 | -16.7   1.9  245  12  6   8.2   4.5
 17500 -14.7   5.5  275  20 11   8.6   4.7 | -15.5   4.1  255  12  6   8.3   4.6
 17000 -13.4   7.9  275  20 10   8.9   4.9 | -14.1   6.6  255  11  6   9.6   5.3
 16500 -12.1  10.2  280  21 11   8.8   4.8 | -12.7   9.1  255  12  6   9.5   5.2
 16000 -10.8  12.6  280  21 11   9.3   5.1 | -11.3  11.7  255  12  6   9.8   5.4
 15500  -9.4  15.1  280  20 10   9.3   5.1 |  -9.8  14.4  255  12  6   9.9   5.4
 15000  -7.3  18.9  285  19 10   9.6   5.3 |  -7.6  18.3  255  12  6   9.7   5.3
 14500  -5.9  21.4  285  19 10   9.6   5.3 |  -6.1  21.0  255  12  6   9.8   5.4
 14000  -4.5  23.9  285  18  9   9.1   5.0 |  -4.7  23.5  260  13  6   9.5   5.2
 13500  -3.1  26.4  285  18  9   9.1   5.0 |  -3.3  26.1  260  12  6   9.4   5.2
 13000  -1.8  28.8  285  17  9   8.9   4.9 |  -1.9  28.6  260  12  6   9.3   5.1
 12500  -0.5  31.1  285  17  9   8.9   4.9 |  -0.5  31.1  260  12  6   9.3   5.1
 12000   0.9  33.6  285  16  8   8.8   4.8 |   0.9  33.6  255  11  6   9.3   5.1
 11500   2.2  36.0  285  15  8   8.7   4.8 |   2.3  36.1  255  10  5   9.2   5.1
 11000   3.4  38.1  280  13  7   8.4   4.6 |   3.6  38.5  250  10  5   8.6   4.7
 10500   4.7  40.5  280  12  6   7.7   4.2 |   4.8  40.6  240   9  5   7.6   4.2
 10250   5.3  41.5  280  11  6  10.0   5.5 |   5.4  41.7  240   9  4   9.7   5.3
 10000   6.1  43.0  275  11  6   9.9   5.4 |   6.2  43.2  235   8  4  10.0   5.5
  9750   6.7  44.1  275  10  5   7.7   4.2 |   6.9  44.4  230   8  4   8.1   4.4
  9500   7.3  45.1  270   9  5   8.1   4.5 |   7.5  45.5  225   8  4   8.7   4.8
  9250   7.9  46.2  270   8  4   8.7   4.8 |   8.1  46.6  220   7  4   8.1   4.4
  9000   8.6  47.5  265   8  4   8.3   4.5 |   8.7  47.7  215   7  4   7.6   4.2
  8750   9.1  48.4  265   7  4   7.3   4.0 |   9.3  48.7  215   7  4   7.8   4.3
  8500   9.7  49.5  265   6  3   7.4   4.0 |   9.9  49.8  210   7  3   7.6   4.2
  8250  10.2  50.4  265   6  3   7.9   4.3 |  10.4  50.7  205   6  3   8.3   4.6
  8000  10.8  51.4  265   5  2   7.9   4.3 |  11.1  52.0  200   6  3   7.7   4.2
  7750  11.3  52.3  270   4  2   6.4   3.5 |  11.5  52.7  195   4  2   6.0   3.3
  7500  11.8  53.2  280   4  2   6.4   3.5 |  11.9  53.4  185   3  2   5.5   3.0
  7250  12.3  54.1  290   3  2   5.5   3.0 |  12.3  54.1  165   2  1   6.5   3.6
  7000  12.6  54.7  305   2  1   4.1   2.2 |  12.8  55.0  145   2  1   7.7   4.2
  6750  12.9  55.2  325   2  1   3.7   2.0 |  13.3  55.9  120   2  1   7.8   4.3
  6500  13.1  55.6  345   2  1   2.3   1.3 |  13.9  57.0  110   1  1   8.1   4.4
  6250  13.1  55.6  355   1  1  -2.5  -1.3 |  14.5  58.1  095   1  1  10.2   5.6
  6000  12.8  55.0  310   1  0  -4.7  -2.6 |  15.4  59.7  090   1  1  11.9   6.5
  5750  12.3  54.1  265   1  1  -7.4  -4.1 |  16.2  61.2  080   1  1   9.9   5.4
  5500  11.6  52.9  235   2  1  -7.0  -3.8 |  16.9  62.4  070   1  1  11.9   6.5

           04/12/2014 at 1500 MDT          |       04/12/2014 at 1800 MDT
                                           |
K index... +18.9  LI... -0.5               | K index... +21.2  LI... +0.3
CAPE... +28.6  CIN... -12.2                | CAPE... 0.0  CIN... -0.9
                                           |
Height Temperature  Wnd WndSpd  Lapse Rate | Temperature  Wnd WndSpd  Lapse Rate
ft MSL deg C deg F  Dir kt m/s  C/km F/kft | deg C deg F  Dir kt m/s  C/km F/kft
--------------------------------------------------------------------------------
 50000 -59.9 -75.8  265  40 20   1.0   0.6 | -58.8 -73.8  265  43 22   1.1   0.6
 45000 -58.3 -72.9  255  47 24   1.2   0.7 | -57.0 -70.6  260  51 26   1.3   0.7
 40000 -56.3 -69.3  250  51 26   1.3   0.7 | -54.8 -66.6  255  44 23   1.5   0.8
 38000 -55.8 -68.4  245  50 26   0.3   0.2 | -54.6 -66.3  250  40 21  -1.0  -0.5
 36000 -55.6 -68.1  240  47 24   0.3   0.2 | -55.2 -67.4  245  35 18  -1.0  -0.5
 34000 -54.9 -66.8  235  45 23   8.9   4.9 | -55.4 -67.7  235  32 16   6.4   3.5
 32000 -50.1 -58.2  230  43 22   8.0   4.4 | -51.0 -59.8  235  30 15   7.4   4.0
 30000 -44.6 -48.3  230  40 21   8.4   4.6 | -45.7 -50.3  235  27 14   9.1   5.0
 29000 -42.1 -43.8  235  38 20   8.4   4.6 | -43.0 -45.4  240  25 13   9.2   5.1
 28000 -39.6 -39.3  240  36 18   8.4   4.6 | -40.2 -40.4  245  23 12   9.2   5.1
 27000 -37.1 -34.8  250  34 18   8.4   4.6 | -37.5 -35.5  250  22 11   8.8   4.9
 26000 -34.6 -30.3  245  32 16   8.3   4.6 | -34.9 -30.8  255  21 11   8.5   4.6
 25000 -32.1 -25.8  245  30 15   8.4   4.6 | -32.4 -26.3  255  20 10   8.5   4.6
 24000 -29.6 -21.3  240  28 14   8.1   4.4 | -29.9 -21.8  260  19 10   8.4   4.6
 23000 -27.4 -17.3  240  27 14   7.5   4.1 | -27.5 -17.5  255  17  9   8.1   4.5
 22000 -25.1 -13.2  240  26 13   7.5   4.1 | -25.1 -13.2  245  14  7   8.1   4.5
 21000 -22.9  -9.2  240  25 13   7.7   4.2 | -22.7  -8.9  235  13  7   7.7   4.2
 20000 -20.6  -5.1  235  22 11   7.7   4.2 | -20.4  -4.7  225  11  6   7.5   4.1
 19500 -19.5  -3.1  235  21 11   7.7   4.2 | -19.3  -2.7  220  11  6   7.5   4.1
 19000 -18.3  -0.9  230  20 10   7.7   4.2 | -18.2  -0.8  215  11  5   7.5   4.1
 18500 -17.2   1.0  230  18  9   7.9   4.3 | -17.1   1.2  205  10  5   7.5   4.1
 18000 -16.0   3.2  225  18  9   8.0   4.4 | -16.0   3.2  200  10  5   7.5   4.1
 17500 -14.8   5.4  225  17  9   8.0   4.4 | -14.9   5.2  200  10  5   7.5   4.1
 17000 -13.6   7.5  220  17  9   8.3   4.6 | -13.8   7.2  195  10  5   8.0   4.4
 16500 -12.4   9.7  220  16  8   8.3   4.6 | -12.6   9.3  190   9  5   8.1   4.4
 16000 -11.2  11.8  220  16  8   7.6   4.2 | -11.4  11.5  190   8  4   8.5   4.6
 15500 -10.1  13.8  215  15  8   7.4   4.0 | -10.1  13.8  185   8  4   8.8   4.8
 15000  -8.4  16.9  215  13  7   8.8   4.8 |  -8.2  17.2  180   8  4   8.1   4.5
 14500  -7.1  19.2  215  12  6   8.8   4.9 |  -7.0  19.4  185   7  4   8.0   4.4
 14000  -5.7  21.7  215  11  6   9.2   5.0 |  -5.8  21.6  185   7  4   8.1   4.5
 13500  -4.4  24.1  215  11  6   9.3   5.1 |  -4.6  23.7  190   7  4   8.2   4.5
 13000  -3.0  26.6  215  11  6   9.6   5.3 |  -3.4  25.9  190   7  4   8.5   4.6
 12500  -1.5  29.3  215  11  6   9.9   5.4 |  -2.0  28.4  195   7  4   8.9   4.9
 12000   0.0  32.0  215  11  5   9.9   5.4 |  -0.7  30.7  200   7  4   8.9   4.9
 11500   1.5  34.7  220  10  5   9.8   5.4 |   0.6  33.1  205   7  4   9.0   4.9
 11000   2.9  37.2  220  10  5   9.3   5.1 |   2.0  35.6  215   8  4   8.8   4.8
 10500   4.2  39.6  220  10  5   8.2   4.5 |   3.2  37.8  220   8  4   8.0   4.4
 10250   4.9  40.8  220  10  5  10.6   5.8 |   3.9  39.0  225   9  4   9.4   5.1
 10000   5.8  42.4  220   9  5  11.5   6.3 |   4.6  40.3  225   9  5  10.3   5.7
  9750   6.5  43.7  220   9  5   9.6   5.2 |   5.3  41.5  230   9  5   9.3   5.1
  9500   7.2  45.0  220   9  5  10.0   5.5 |   6.0  42.8  230  10  5   9.3   5.1
  9250   8.0  46.4  220   9  4   9.6   5.3 |   6.7  44.1  235  10  5   9.0   4.9
  9000   8.7  47.7  220   8  4   9.6   5.2 |   7.4  45.3  235  10  5   8.7   4.8
  8750   9.4  48.9  220   8  4   9.9   5.4 |   8.0  46.4  240  11  6   9.1   5.0
  8500  10.1  50.2  220   8  4   9.5   5.2 |   8.7  47.7  240  11  6   9.2   5.1
  8250  10.9  51.6  225   8  4  10.9   6.0 |   9.4  48.9  245  11  6   9.4   5.2
  8000  11.7  53.1  225   7  4  11.4   6.2 |  10.2  50.4  245  12  6  10.9   6.0
  7750  12.5  54.5  225   7  4   9.4   5.2 |  11.0  51.8  250  12  6  10.2   5.6
  7500  13.2  55.8  225   7  4   8.7   4.8 |  11.7  53.1  250  12  6   8.9   4.9
  7250  13.8  56.8  225   7  3   9.7   5.3 |  12.3  54.1  250  12  6   9.1   5.0
  7000  14.6  58.3  225   7  3  10.8   5.9 |  13.0  55.4  250  12  6   9.1   5.0
  6750  15.4  59.7  225   6  3   9.8   5.4 |  13.7  56.7  250  12  6   9.9   5.5
  6500  16.1  61.0  225   6  3   8.9   4.9 |  14.5  58.1  250  12  6  10.5   5.8
  6250  16.8  62.2  225   6  3  10.3   5.6 |  15.3  59.5  250  12  6  10.0   5.5
  6000  17.6  63.7  230   6  3  11.6   6.4 |  16.0  60.8  250  11  6   9.6   5.2
  5750  18.4  65.1  230   6  3  10.4   5.7 |  16.7  62.1  250  11  6  10.1   5.5
  5500  19.2  66.6  230   5  3  12.6   6.9 |  17.5  63.5  255  10  5  11.4   6.2
________________________________________________________________________________

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.