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 24 25 26 27
000
UXUS97 KBOU 211246
SRGBOU

Soaring Forecast
National Weather Service Denver/Boulder, Colorado
0646 MDT Sunday, September 21, 2014

This forecast is for Sunday, September 21, 2014:

If the trigger temperature of 69.6 F/20.9 C is reached...then
   Thermal Soaring Index....................... Poor
   Maximum rate of lift........................ 33 ft/min (0.2 m/s)
   Maximum height of thermals.................. 10922 ft MSL (5637 ft AGL)

Forecast maximum temperature................... 72.0 F/22.7 C
Time of trigger temperature.................... 1330 MDT
Time of overdevelopment........................ 1500 MDT
Middle/high clouds during soaring window....... Broken/overcast opaque middle
Surface winds during soaring window............ 20 mph or less
Height of the -3 thermal index................. 7252 ft MSL (1967 ft AGL)
Thermal soaring outlook for Monday 09/22....... Poor

Wave Soaring Index............................. Fair
Wave Soaring Index trend (to 1800 MDT)......... Becoming poor
Height of stable layer (12-18K ft MSL)......... 15127 ft MSL (9842 ft AGL)
Weak PVA/NVA (through 1800 MDT)................ Weak PVA
Potential height of wave....................... 15865 ft MSL (10580 ft AGL)
Wave soaring outlook for Monday 09/22.......... Poor

Remarks... Scattered showers and thunderstorms

Sunrise/Sunset.................... 06:46:10 / 18:59:42 MDT
Total possible sunshine........... 12 hr 13 min 32 sec (733 min 32 sec)
Altitude of sun at 12:52:26 MDT... 50.75 degrees

Upper air data from rawinsonde observation taken on 09/21/2014 at 0600 MDT

Freezing level.................. 15854 ft MSL (10569 ft AGL)
Convective condensation level... 11764 ft MSL (6479 ft AGL)
Lifted condensation level....... 11318 ft MSL (6033 ft AGL)
Lifted index.................... +0.8
K index......................... +24.0

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  -67.7 -89.9   270   46   24  -3.5  -1.9   81.1 178.0    34.2      M    M
 45000  -61.9 -79.4   285   65   33   7.2   3.9   64.7 148.4    26.6      M    M
 40000  -51.3 -60.3   280   69   35   6.4   3.5   58.8 137.9    24.5      M    M
 38000  -47.9 -54.2   280   56   29   4.4   2.4   55.2 131.4    22.6      M    M
 36000  -43.7 -46.7   280   43   22   7.7   4.2   52.8 127.1    21.6      M    M
 34000  -40.3 -40.5   280   41   21   8.2   4.5   49.4 121.0    19.7      M    M
 32000  -35.7 -32.3   275   38   20   7.7   4.2   47.8 118.0    18.9      M    M
 30000  -30.8 -23.4   270   40   20   7.3   4.0   45.5 114.0    17.7      M    M
 29000  -28.5 -19.3   265   38   20   7.7   4.2   44.7 112.4    17.2      M    M
 28000  -26.3 -15.3   260   37   19   7.7   4.2   43.9 111.0    16.8      M    M
 27000  -24.0 -11.2   260   33   17   7.6   4.2   43.1 109.5    16.3      M    M
 26000  -21.7  -7.1   255   29   15   7.6   4.2   42.3 108.1    15.9      M    M
 25000  -19.5  -3.1   275   26   13   7.7   4.2   41.5 106.7    15.4      M    M
 24000  -17.4   0.7   280   21   11  -2.0  -1.1   40.4 104.7    14.7      M    M
 23000  -16.0   3.2   290   16    8   7.0   3.9   38.4 101.2    13.3      M    M
 22000  -14.5   5.9   310   12    6   5.3   2.9   36.8  98.2    12.1      M    M
 21000  -12.7   9.1   315   11    6   8.4   4.6   35.4  95.7    11.0      M    M
 20000  -10.1  13.8   325   10    5   8.8   4.8   35.1  95.1    10.8      M    M
 19500   -8.9  16.0   320   11    5   8.2   4.5   34.8  94.7    10.6      M    M
 19000   -8.0  17.6   310   11    6   6.9   3.8   34.4  93.9    10.1      M    M
 18500   -6.9  19.6   315   11    6   7.4   4.1   34.0  93.2     9.8      M    M
 18000   -5.9  21.4   320   11    6   7.6   4.2   33.6  92.5     9.4      M    M
 17500   -4.6  23.7   310   11    6   9.0   4.9   33.3  92.0     9.2      M    M
 17000   -3.3  26.1   300   11    6   8.9   4.9   33.2  91.7     9.1      M    M
 16500   -2.0  28.4   290   11    6   8.9   4.9   33.1  91.5     9.0      M    M
 16000   -0.7  30.7   280   12    6   8.7   4.8   33.0  91.3     9.0      M    M
 15500    0.6  33.1   265   11    6   6.5   3.6   32.8  91.1     8.9      M    M
 15000    1.0  33.8   235   12    6   1.9   1.0   31.0  87.7     7.1      M    M
 14500    1.2  34.2   220   14    7   2.3   1.3   29.7  85.4     5.9      M    M
 14000    1.6  34.9   210   16    8   2.9   1.6   28.5  83.4     4.8      M    M
 13500    2.0  35.6   215   17    9   2.9   1.6   27.4  81.3     3.8      M    M
 13000    2.4  36.3   220   17    9   3.1   1.7   26.3  79.4     2.8      M    M
 12500    2.8  37.0   205   14    7   5.2   2.8   25.2  77.4     1.7      M    M
 12000    3.8  38.8   185   12    6   6.8   3.7   24.9  76.8     1.3      M    M
 11500    4.6  40.3   180   15    8   5.9   3.2   24.3  75.7     0.6      M    M
 11000    5.5  41.9   180   18    9   5.8   3.2   23.6  74.5     0.0      M    M
 10500    6.3  43.3   180   21   11   6.2   3.4   23.1  73.5    -0.6    394  2.0
 10250    6.8  44.2   180   21   11   7.4   4.1   22.8  73.1    -0.8    373  1.9
 10000    7.4  45.3   180   21   11   8.2   4.5   22.7  72.8    -0.9    348  1.8
  9750    8.0  46.4   185   20   10   8.1   4.4   22.6  72.6    -1.1    322  1.6
  9500    8.6  47.5   185   19   10   8.1   4.4   22.4  72.4    -1.2    297  1.5
  9250    9.1  48.4   190   19   10   8.1   4.4   22.3  72.2    -1.3    272  1.4
  9000    9.7  49.5   190   18    9   8.1   4.4   22.2  72.0    -1.5    247  1.3
  8750   10.3  50.5   190   16    8   8.1   4.4   22.1  71.7    -1.6    222  1.1
  8500   10.9  51.6   190   14    7   8.1   4.4   21.9  71.5    -1.7    197  1.0
  8250   11.5  52.7   185   13    7   8.1   4.5   21.8  71.3    -1.9    171  0.9
  8000   12.1  53.8   185   11    6   8.1   4.4   21.7  71.1    -2.0    146  0.7
  7750   12.7  54.9   180    9    5   8.2   4.5   21.6  70.8    -2.2    121  0.6
  7500   13.2  55.8   175    7    4   4.4   2.4   21.4  70.4    -2.4     98  0.5
  7250   13.3  55.9   160    5    3   0.9   0.5   20.8  69.4    -3.0     87  0.4
  7000   13.4  56.1   140    4    2   0.2   0.1   20.1  68.1    -3.6     77  0.4
  6750   13.5  56.3   130    3    2  -0.0  -0.0   19.3  66.8    -4.3     67  0.3
  6500   13.7  56.7   120    3    1   3.4   1.9   18.7  65.6    -4.8     54  0.3
  6250   14.1  57.4   100    2    1   5.2   2.8   18.3  65.0    -5.2     36  0.2
  6000   14.4  57.9   075    2    1   4.7   2.6   18.0  64.3    -5.6     18  0.1
  5750   14.8  58.6   035    1    1   4.7   2.6   17.6  63.6    -6.0      M    M
  5500   15.1  59.2   335    2    1   5.2   2.9   17.2  63.0    -6.3      M    M

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

           09/21/2014 at 0900 MDT          |       09/21/2014 at 1200 MDT
                                           |
K index... +27.2  LI... +0.9               | K index... +27.2  LI... -0.0
CAPE... 0.0  CIN... -0.6                   | CAPE... +40.9  CIN... -110.1
                                           |
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 -66.7 -88.1  290  38 19   2.4   1.3 | -67.8 -90.0  285  34 18   2.3   1.2
 45000 -61.2 -78.2  285  59 30   6.0   3.3 | -62.1 -79.8  285  52 27   6.5   3.6
 40000 -52.3 -62.1  280  60 31   5.6   3.1 | -52.4 -62.3  275  54 28   5.8   3.2
 38000 -48.9 -56.0  270  54 28   5.6   3.1 | -48.9 -56.0  270  45 23   5.8   3.2
 36000 -45.6 -50.1  260  49 25   5.3   2.9 | -45.4 -49.7  255  37 19   5.7   3.1
 34000 -40.5 -40.9  260  44 23   8.7   4.8 | -40.3 -40.5  255  33 17   8.8   4.9
 32000 -35.3 -31.5  265  40 20   8.6   4.7 | -35.0 -31.0  260  29 15   8.7   4.8
 30000 -29.8 -21.6  270  35 18   8.1   4.4 | -29.4 -20.9  265  25 13   8.2   4.5
 29000 -27.4 -17.3  270  33 17   8.1   4.5 | -27.0 -16.6  265  24 12   8.2   4.5
 28000 -25.1 -13.2  275  31 16   7.2   3.9 | -24.6 -12.3  270  23 12   7.2   3.9
 27000 -22.9  -9.2  280  28 14   7.2   4.0 | -22.5  -8.5  280  22 11   7.3   4.0
 26000 -20.8  -5.4  280  25 13   7.2   4.0 | -20.4  -4.7  285  21 11   7.3   4.0
 25000 -18.7  -1.7  285  23 12   6.5   3.5 | -18.2  -0.8  295  21 11   5.9   3.3
 24000 -16.9   1.6  290  19 10   5.3   2.9 | -17.1   1.2  295  17  9   3.3   1.8
 23000 -15.2   4.6  295  15  8   5.5   3.0 | -16.1   3.0  305  13  7   3.4   1.8
 22000 -13.6   7.5  310  11  6   6.0   3.3 | -15.1   4.8  315   9  5   5.6   3.1
 21000 -11.6  11.1  310  10  5   6.5   3.6 | -12.5   9.5  310   6  3   8.4   4.6
 20000  -9.7  14.5  310   9  4   6.6   3.6 |  -9.9  14.2  295   3  2   8.5   4.7
 19500  -8.7  16.3  315   8  4   6.6   3.6 |  -8.6  16.5  270   2  1   8.6   4.7
 19000  -7.8  18.0  310   8  4   6.2   3.4 |  -7.5  18.5  265   2  1   6.8   3.7
 18500  -6.9  19.6  310   8  4   6.7   3.7 |  -6.5  20.3  290   1  1   7.0   3.9
 18000  -6.1  21.0  305   8  4   6.8   3.8 |  -5.5  22.1  315   1  1   7.0   3.8
 17500  -5.2  22.6  295   8  4   6.7   3.7 |  -4.5  23.9  305   2  1   7.1   3.9
 17000  -4.3  24.3  285   9  4   6.9   3.8 |  -3.6  25.5  300   2  1   7.4   4.1
 16500  -3.3  26.1  280   9  4   7.5   4.1 |  -2.7  27.1  285   2  1   6.3   3.5
 16000  -2.3  27.9  275   8  4   7.6   4.2 |  -1.9  28.6  270   2  1   6.6   3.6
 15500  -1.3  29.7  270   8  4   6.3   3.5 |  -0.6  30.9  255   2  1   5.9   3.2
 15000   0.0  32.0  265   8  4   6.1   3.3 |   0.2  32.4  250   3  2   6.0   3.3
 14500   0.9  33.6  260   9  4   5.9   3.2 |   1.0  33.8  240   4  2   5.8   3.2
 14000   1.8  35.2  255   9  5   5.9   3.3 |   1.9  35.4  230   6  3   5.9   3.2
 13500   2.6  36.7  250   9  5   6.0   3.3 |   2.7  36.9  220   7  4   5.9   3.2
 13000   3.5  38.3  245  10  5   6.0   3.3 |   3.6  38.5  215   9  5   5.8   3.2
 12500   4.4  39.9  240  11  6   6.2   3.4 |   4.5  40.1  210  12  6   6.0   3.3
 12000   5.3  41.5  235  12  6   6.3   3.4 |   5.4  41.7  205  14  7   6.1   3.3
 11500   6.2  43.2  235  13  7   6.1   3.4 |   6.3  43.3  200  17  9   6.5   3.6
 11000   7.1  44.8  230  13  7   6.1   3.3 |   7.3  45.1  200  18  9   6.8   3.7
 10500   8.0  46.4  225  13  7   4.1   2.2 |   8.2  46.8  205  20 10   5.4   2.9
 10250   8.2  46.8  220  13  7   2.9   1.6 |   8.6  47.5  205  20 10   6.0   3.3
 10000   8.4  47.1  215  14  7   3.8   2.1 |   9.2  48.6  205  21 11   8.6   4.7
  9750   8.7  47.7  210  14  7   4.0   2.2 |   9.8  49.6  205  23 12   8.4   4.6
  9500   9.0  48.2  205  15  8   4.8   2.6 |  10.4  50.7  205  24 12   6.2   3.4
  9250   9.3  48.7  205  17  9   4.9   2.7 |  10.8  51.4  205  25 13   4.8   2.6
  9000   9.7  49.5  205  18  9   5.8   3.2 |  11.2  52.2  205  25 13   6.8   3.7
  8750  10.2  50.4  200  20 10   6.2   3.4 |  11.7  53.1  205  26 14   7.4   4.1
  8500  10.6  51.1  200  21 11   5.1   2.8 |  12.2  54.0  205  27 14   6.0   3.3
  8250  11.0  51.8  200  23 12   4.5   2.5 |  12.6  54.7  205  27 14   5.5   3.0
  8000  11.3  52.3  200  24 13   6.1   3.4 |  13.0  55.4  210  28 14   6.8   3.7
  7750  11.8  53.2  200  26 13   5.0   2.7 |  13.6  56.5  210  28 14   7.0   3.8
  7500  12.0  53.6  195  25 13   2.6   1.4 |  13.9  57.0  205  26 13   5.8   3.2
  7250  12.2  54.0  195  24 12   2.5   1.4 |  14.3  57.7  205  24 12   5.7   3.2
  7000  12.4  54.3  190  23 12   4.8   2.6 |  14.7  58.5  200  22 11   6.9   3.8
  6750  12.9  55.2  190  22 11   8.2   4.5 |  15.3  59.5  195  21 11   9.6   5.3
  6500  13.4  56.1  190  20 11   8.3   4.6 |  16.0  60.8  195  20 10  10.5   5.8
  6250  14.0  57.2  185  19 10   8.0   4.4 |  16.7  62.1  195  19 10  10.1   5.5
  6000  14.6  58.3  185  17  9   9.3   5.1 |  17.5  63.5  195  18  9  11.0   6.0
  5750  15.4  59.7  185  15  8  13.0   7.2 |  18.4  65.1  195  17  9  15.2   8.3
  5500  16.4  61.5  180  13  7  15.5   8.5 |  19.7  67.5  190  15  8  19.7  10.8

           09/21/2014 at 1500 MDT          |       09/21/2014 at 1800 MDT
                                           |
K index... +24.1  LI... -1.7               | K index... +24.2  LI... -1.5
CAPE... +56.5  CIN... -97.1                | CAPE... +54.4  CIN... -100.4
                                           |
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 -67.0 -88.6  285  30 16   2.1   1.2 | -66.7 -88.1  285  31 16   2.6   1.4
 45000 -61.7 -79.1  285  45 23   6.2   3.4 | -61.1 -78.0  280  46 24   5.7   3.2
 40000 -52.5 -62.5  275  58 30   6.1   3.4 | -52.4 -62.3  275  58 30   6.2   3.4
 38000 -48.8 -55.8  275  48 25   6.1   3.4 | -48.7 -55.7  280  47 24   6.3   3.4
 36000 -45.1 -49.2  270  38 20   5.8   3.2 | -44.9 -48.8  285  36 18   6.0   3.3
 34000 -40.4 -40.7  265  34 18   8.2   4.5 | -40.0 -40.0  280  32 17   8.4   4.6
 32000 -34.9 -30.8  250  32 16   8.8   4.8 | -34.3 -29.7  280  30 15   9.0   5.0
 30000 -29.8 -21.6  260  27 14   8.6   4.7 | -29.5 -21.1  275  27 14   8.1   4.4
 29000 -27.2 -17.0  265  24 13   8.6   4.7 | -27.1 -16.8  270  26 14   8.1   4.5
 28000 -24.7 -12.5  275  23 12   7.4   4.1 | -24.7 -12.5  270  25 13   7.3   4.0
 27000 -22.6  -8.7  270  22 11   7.4   4.1 | -22.6  -8.7  275  22 11   7.3   4.0
 26000 -20.4  -4.7  270  21 11   7.4   4.1 | -20.4  -4.7  275  19 10   7.3   4.0
 25000 -18.2  -0.8  270  20 10   7.2   3.9 | -18.3  -0.9  280  16  8   7.1   3.9
 24000 -16.3   2.7  275  16  8   6.5   3.5 | -16.3   2.7  280  12  6   6.5   3.6
 23000 -14.3   6.3  280  12  6   6.5   3.5 | -14.4   6.1  270   9  4   6.5   3.6
 22000 -12.4   9.7  290   9  5   5.5   3.0 | -12.5   9.5  250   5  3   6.0   3.3
 21000 -11.2  11.8  295   6  3   3.7   2.0 | -11.0  12.2  240   3  2   4.7   2.6
 20000 -10.1  13.8  315   3  1   3.7   2.0 |  -9.5  14.9  190   1  0   4.8   2.6
 19500  -9.5  14.9  350   2  1   3.2   1.8 |  -8.7  16.3  115   1  1   4.5   2.5
 19000  -8.6  16.5  035   1  1   8.2   4.5 |  -7.8  18.0  105   2  1   7.2   3.9
 18500  -7.4  18.7  085   1  1   7.7   4.2 |  -6.8  19.8  115   2  1   7.0   3.9
 18000  -6.3  20.7  120   2  1   8.3   4.6 |  -5.7  21.7  125   2  1   7.0   3.9
 17500  -5.0  23.0  120   2  1   9.1   5.0 |  -4.7  23.5  130   2  1   7.1   3.9
 17000  -3.7  25.3  115   2  1   9.3   5.1 |  -3.8  25.2  135   2  1   7.2   3.9
 16500  -2.5  27.5  115   2  1   7.3   4.0 |  -2.7  27.1  130   3  1   7.8   4.3
 16000  -1.5  29.3  115   3  2   7.8   4.3 |  -1.1  30.0  125   4  2   8.0   4.4
 15500  -0.2  31.6  115   3  2   5.7   3.1 |  -0.1  31.8  125   4  2   7.4   4.1
 15000   0.6  33.1  120   3  2   5.9   3.2 |   0.9  33.6  120   4  2   7.6   4.2
 14500   1.5  34.7  130   3  1   6.2   3.4 |   1.9  35.4  120   3  2   6.6   3.6
 14000   2.4  36.3  160   3  2   6.2   3.4 |   2.9  37.2  110   2  1   6.5   3.6
 13500   3.2  37.8  180   4  2   5.7   3.1 |   3.8  38.8  080   1  1   6.0   3.3
 13000   4.1  39.4  190   5  3   5.6   3.0 |   4.6  40.3  010   1  0   5.7   3.2
 12500   4.9  40.8  200   7  4   5.9   3.2 |   5.5  41.9  335   1  1   5.9   3.2
 12000   5.8  42.4  200   8  4   6.1   3.3 |   6.4  43.5  310   1  1   6.1   3.4
 11500   6.7  44.1  205  10  5   6.5   3.5 |   7.3  45.1  280   1  1   6.6   3.6
 11000   7.7  45.9  205  13  7   6.6   3.6 |   8.3  46.9  250   3  2   6.9   3.8
 10500   8.7  47.7  205  16  8   3.1   1.7 |   9.4  48.9  245   5  3   3.3   1.8
 10250   8.8  47.8  205  17  9   3.0   1.6 |   9.5  49.1  240   5  3   4.9   2.7
 10000   9.3  48.7  205  18  9   8.8   4.8 |  10.3  50.5  235   7  4  12.0   6.6
  9750   9.9  49.8  200  20 10   9.0   4.9 |  11.1  52.0  235   9  5  12.7   7.0
  9500  10.5  50.9  200  22 11   7.0   3.9 |  12.0  53.6  230  11  6   8.4   4.6
  9250  10.9  51.6  200  23 12   5.1   2.8 |  12.3  54.1  225  13  7   4.0   2.2
  9000  11.4  52.5  200  24 12   8.3   4.5 |  12.7  54.9  225  15  8   6.9   3.8
  8750  12.1  53.8  200  25 13   9.8   5.4 |  13.2  55.8  220  17  9   7.9   4.3
  8500  12.7  54.9  200  25 13   6.9   3.8 |  13.7  56.7  215  19 10   6.6   3.6
  8250  13.2  55.8  195  26 13   5.8   3.2 |  14.1  57.4  210  20 10   5.9   3.2
  8000  13.6  56.5  195  26 13   6.3   3.4 |  14.5  58.1  210  22 11   6.3   3.4
  7750  14.1  57.4  195  27 14   6.1   3.4 |  14.9  58.8  205  22 12   6.0   3.3
  7500  14.5  58.1  195  26 13   5.9   3.3 |  15.3  59.5  200  22 11   4.9   2.7
  7250  14.8  58.6  190  25 13   5.9   3.2 |  15.6  60.1  195  21 11   4.7   2.6
  7000  15.2  59.4  185  24 12   6.4   3.5 |  15.9  60.6  190  20 10   3.9   2.2
  6750  15.6  60.1  180  22 12   9.0   4.9 |  16.2  61.2  180  19 10   6.7   3.7
  6500  16.4  61.5  180  22 11  10.6   5.8 |  16.9  62.4  180  18 10  10.0   5.5
  6250  17.1  62.8  180  21 11   9.9   5.4 |  17.6  63.7  180  18  9   9.2   5.0
  6000  17.9  64.2  180  21 11  11.1   6.1 |  18.3  64.9  175  17  9  10.3   5.7
  5750  18.9  66.0  180  19 10  15.5   8.5 |  19.1  66.4  175  16  8  11.7   6.4
  5500  20.2  68.4  180  18  9  19.6  10.8 |  19.9  67.8  175  14  7  11.0   6.0
________________________________________________________________________________

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.