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
000
UXUS97 KBOU 181319
SRGBOU

Soaring Forecast
National Weather Service Denver/Boulder, Colorado
0719 MDT Monday, August 18, 2014

This forecast is for Monday, August 18, 2014:

If the trigger temperature of 85.9 F/30.0 C is reached...then
   Thermal Soaring Index....................... Excellent
   Maximum rate of lift........................ 1566 ft/min (8.0 m/s)
   Maximum height of thermals.................. 20624 ft MSL (15339 ft AGL)

Forecast maximum temperature................... 90.0 F/32.7 C
Time of trigger temperature.................... 1115 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................. 8711 ft MSL (3425 ft AGL)
Thermal soaring outlook for Tuesday 08/19...... Fair

Wave Soaring Index............................. Poor
Wave Soaring Index trend (to 1800 MDT)......... No change
Height of stable layer (12-18K ft MSL)......... None
Weak PVA/NVA (through 1800 MDT)................ Neither
Potential height of wave....................... 39778 ft MSL (34493 ft AGL)
Wave soaring outlook for Tuesday 08/19......... Poor

Remarks... Scattered afternoon thunderstorms

Sunrise/Sunset.................... 06:14:22 / 19:52:43 MDT
Total possible sunshine........... 13 hr 38 min 21 sec (818 min 21 sec)
Altitude of sun at 13:03:11 MDT... 63.16 degrees

Upper air data from rawinsonde observation taken on 08/18/2014 at 0600 MDT

Freezing level.................. 15676 ft MSL (10391 ft AGL)
Convective condensation level... 17582 ft MSL (12297 ft AGL)
Lifted condensation level....... 18122 ft MSL (12836 ft AGL)
Lifted index.................... -1.0
K index......................... +20.8

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  -61.9 -79.4   295   20   10  -8.1  -4.4   89.7 193.4    33.5      M    M
 45000  -59.8 -75.6   275   37   19   5.9   3.2   68.8 155.8    22.8      M    M
 40000  -52.6 -62.7   285   52   27  -5.9  -3.2   57.3 135.1    16.8      M    M
 38000  -51.7 -61.1   285   48   25   6.5   3.5   49.9 121.8    12.1      M    M
 36000  -47.7 -53.9   290   43   22   7.4   4.1   47.2 117.0    10.6      M    M
 34000  -43.1 -45.6   300   40   21   7.1   3.9   45.4 113.8     9.6      M    M
 32000  -38.0 -36.4   290   36   18   8.0   4.4   43.4 110.0     8.3      M    M
 30000  -33.1 -27.6   290   29   15   8.3   4.5   42.2 108.0     7.6      M    M
 29000  -30.6 -23.1   290   28   14   7.8   4.3   41.6 106.8     7.2      M    M
 28000  -28.3 -18.9   290   27   14   7.7   4.2   40.8 105.4     6.6      M    M
 27000  -25.7 -14.3   295   27   14   9.1   5.0   40.4 104.7     6.4      M    M
 26000  -23.0  -9.4   295   26   13   8.7   4.8   40.2 104.3     6.3      M    M
 25000  -20.5  -4.9   295   25   13   9.0   4.9   39.6 103.3     5.9      M    M
 24000  -18.5  -1.3   300   22   12   5.5   3.0   38.4 101.2     5.0      M    M
 23000  -17.1   1.2   310   21   11   3.2   1.7   36.7  98.1     3.6      M    M
 22000  -16.3   2.7   330   20   10   5.9   3.2   34.2  93.6     1.5      M    M
 21000  -13.9   7.0   325   17    9  10.0   5.5   33.7  92.6     1.0      M    M
 20000  -12.6   9.3   315   14    7   9.4   5.1   31.9  89.5    -0.7   1519  7.7
 19500  -11.2  11.8   315   13    7   9.3   5.1   31.9  89.3    -0.8   1463  7.4
 19000   -9.9  14.2   315   13    7   8.9   4.9   31.7  89.1    -0.9   1408  7.2
 18500   -8.5  16.7   310   13    7   9.0   4.9   31.6  88.9    -1.0   1353  6.9
 18000   -7.2  19.0   310   13    7   9.4   5.2   31.5  88.7    -1.2   1299  6.6
 17500   -5.7  21.7   305   13    7   9.8   5.4   31.5  88.7    -1.2   1240  6.3
 17000   -4.3  24.3   305   13    7   9.8   5.4   31.5  88.7    -1.2   1181  6.0
 16500   -2.8  27.0   305   13    7   9.8   5.4   31.5  88.7    -1.2   1122  5.7
 16000   -0.6  30.9   300   13    7   9.8   5.4   31.6  88.9    -1.1   1034  5.3
 15500    0.9  33.6   300   12    6   9.8   5.4   31.5  88.8    -1.1    976  5.0
 15000    2.3  36.1   305   11    6   9.8   5.4   31.5  88.8    -1.2    917  4.7
 14500    3.8  38.8   305   10    5   9.8   5.4   31.5  88.8    -1.2    858  4.4
 14000    5.2  41.4   310    9    4   9.5   5.2   31.5  88.8    -1.2    800  4.1
 13500    6.6  43.9   300    7    4   9.5   5.2   31.5  88.7    -1.3    744  3.8
 13000    8.0  46.4   290    6    3   9.5   5.2   31.5  88.6    -1.3    687  3.5
 12500    9.4  48.9   270    4    2   9.5   5.2   31.4  88.6    -1.4    630  3.2
 12000   10.8  51.4   250    4    2   9.5   5.2   31.4  88.6    -1.4    573  2.9
 11500   12.2  54.0   250    4    2   9.5   5.2   31.4  88.5    -1.5    516  2.6
 11000   13.6  56.5   250    5    2   9.5   5.2   31.3  88.4    -1.6    459  2.3
 10500   15.0  59.0   250    5    3   9.3   5.1   31.3  88.3    -1.6    403  2.0
 10250   15.7  60.3   260    5    3   8.8   4.8   31.2  88.2    -1.7    375  1.9
 10000   16.4  61.5   275    5    3   8.7   4.7   31.2  88.1    -1.8    348  1.8
  9750   17.0  62.6   285    6    3   9.1   5.0   31.1  87.9    -1.9    321  1.6
  9500   17.7  63.9   295    6    3   7.4   4.1   31.0  87.8    -2.0    294  1.5
  9250   18.1  64.6   305    7    4   5.1   2.8   30.7  87.3    -2.2    274  1.4
  9000   18.5  65.3   310    8    4   5.1   2.8   30.4  86.6    -2.6    255  1.3
  8750   18.8  65.8   320   10    5   5.1   2.8   30.0  86.0    -3.0    236  1.2
  8500   19.2  66.6   325   11    6   5.1   2.8   29.6  85.3    -3.3    218  1.1
  8250   19.6  67.3   330   13    7   5.1   2.8   29.3  84.7    -3.7    199  1.0
  8000   20.0  68.0   335   15    8   5.1   2.8   28.9  84.1    -4.0    180  0.9
  7750   20.4  68.7   330   14    7   5.1   2.8   28.6  83.4    -4.4    162  0.8
  7500   20.7  69.3   330   14    7   5.1   2.8   28.2  82.8    -4.8    143  0.7
  7250   21.1  70.0   325   13    7   5.0   2.7   27.8  82.1    -5.1    124  0.6
  7000   21.5  70.7   320   13    7   5.5   3.0   27.5  81.5    -5.5    106  0.5
  6750   21.9  71.4   315   12    6   3.5   1.9   27.1  80.9    -5.9     87  0.4
  6500   22.0  71.6   315   10    5   1.2   0.7   26.5  79.8    -6.5     75  0.4
  6250   21.9  71.4   310    9    5  -5.3  -2.9   25.7  78.3    -7.3     70  0.4
  6000   21.3  70.3   300    8    4  -0.7  -0.4   24.5  76.2    -8.6     81  0.4
  5750   21.7  71.1   300    6    3   8.1   4.4   24.3  75.7    -9.0     61  0.3
  5500   21.2  70.2   300    3    1 -32.4 -17.8   23.1  73.5   -10.2     69  0.3

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

           08/18/2014 at 0900 MDT          |       08/18/2014 at 1200 MDT
                                           |
K index... +16.4  LI... +0.9               | K index... +17.2  LI... -1.7
CAPE... 0.0  CIN... -0.6                   | CAPE... +284.4  CIN... -161.4
                                           |
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 -62.5 -80.5  295  18  9   1.4   0.8 | -62.0 -79.6  285  21 11   1.8   1.0
 45000 -59.2 -74.6  295  34 18   3.9   2.2 | -58.9 -74.0  290  35 18   2.6   1.4
 40000 -53.2 -63.8  290  47 24   4.8   2.6 | -54.6 -66.3  295  49 25   5.8   3.2
 38000 -50.4 -58.7  295  45 23   4.8   2.6 | -51.1 -60.0  295  46 24   5.8   3.2
 36000 -47.5 -53.5  300  44 22   4.7   2.6 | -47.6 -53.7  300  43 22   5.7   3.1
 34000 -43.3 -45.9  300  40 21   7.6   4.1 | -43.3 -45.9  300  40 21   7.6   4.2
 32000 -38.8 -37.8  300  37 19   7.6   4.2 | -38.7 -37.7  300  37 19   7.7   4.2
 30000 -33.1 -27.6  300  32 16   8.6   4.7 | -33.0 -27.4  300  31 16   8.6   4.7
 29000 -30.5 -22.9  300  29 15   8.6   4.7 | -30.5 -22.9  300  28 15   8.6   4.7
 28000 -28.0 -18.4  300  26 14   7.6   4.2 | -27.9 -18.2  295  26 13   7.8   4.3
 27000 -25.8 -14.4  300  24 12   7.3   4.0 | -25.6 -14.1  295  24 12   7.6   4.2
 26000 -23.7 -10.7  300  21 11   7.3   4.0 | -23.4 -10.1  295  22 11   7.6   4.2
 25000 -21.5  -6.7  300  18  9   7.2   3.9 | -21.1  -6.0  295  20 10   7.3   4.0
 24000 -19.6  -3.3  300  16  8   6.2   3.4 | -19.2  -2.6  290  18  9   6.2   3.4
 23000 -17.8  -0.0  300  14  7   6.3   3.4 | -17.4   0.7  285  15  8   6.3   3.5
 22000 -16.0   3.2  300  12  6   7.0   3.9 | -15.6   3.9  275  12  6   6.9   3.8
 21000 -13.6   7.5  295  13  7   8.3   4.6 | -13.3   8.1  280  13  7   7.7   4.2
 20000 -11.1  12.0  290  14  7   8.4   4.6 | -11.0  12.2  280  15  7   7.8   4.3
 19500  -9.9  14.2  285  15  8   8.4   4.6 |  -9.9  14.2  280  15  8   7.7   4.3
 19000  -8.7  16.3  285  15  8   8.0   4.4 |  -8.7  16.3  280  15  8   8.5   4.6
 18500  -7.5  18.5  285  14  7   8.1   4.4 |  -7.5  18.5  280  16  8   8.4   4.6
 18000  -6.3  20.7  290  14  7   8.8   4.8 |  -6.3  20.7  285  16  8   8.8   4.8
 17500  -4.9  23.2  290  12  6   9.5   5.2 |  -4.9  23.2  285  15  8   9.1   5.0
 17000  -3.5  25.7  290  11  6   9.6   5.3 |  -3.6  25.5  285  14  7   9.1   5.0
 16500  -2.1  28.2  285   9  5   8.6   4.7 |  -2.2  28.0  285  14  7   9.5   5.2
 16000  -0.8  30.6  275   8  4   8.7   4.8 |  -0.8  30.6  285  13  7   9.5   5.2
 15500   0.5  32.9  270   7  3   8.9   4.9 |   0.6  33.1  285  13  7   9.4   5.1
 15000   2.5  36.5  250   6  3   9.0   4.9 |   2.7  36.9  285  12  6   9.4   5.1
 14500   3.8  38.8  240   6  3   8.8   4.8 |   4.1  39.4  280  11  6   9.0   4.9
 14000   5.2  41.4  230   6  3   8.8   4.8 |   5.4  41.7  275  10  5   9.0   4.9
 13500   6.5  43.7  220   6  3   9.2   5.1 |   6.8  44.2  270  10  5   8.8   4.8
 13000   7.9  46.2  220   6  3   9.4   5.1 |   8.1  46.6  265   9  5   8.7   4.8
 12500   9.2  48.6  215   6  3   9.4   5.2 |   9.4  48.9  260   9  5   8.8   4.8
 12000  10.6  51.1  215   6  3   9.4   5.2 |  10.7  51.3  255   9  5   8.8   4.8
 11500  12.0  53.6  215   6  3   9.1   5.0 |  12.0  53.6  250   9  5   8.8   4.8
 11000  13.4  56.1  220   5  3   8.5   4.7 |  13.3  55.9  250   9  5   8.4   4.6
 10500  14.7  58.5  230   5  3   3.6   2.0 |  14.6  58.3  250   9  4   3.8   2.1
 10250  14.7  58.5  230   5  3   4.7   2.6 |  14.7  58.5  250   8  4   4.9   2.7
 10000  15.5  59.9  240   5  3  12.0   6.6 |  15.5  59.9  255   8  4  11.7   6.4
  9750  16.3  61.3  250   5  2  10.6   5.8 |  16.3  61.3  255   8  4  10.4   5.7
  9500  17.1  62.8  255   5  2   9.0   5.0 |  17.1  62.8  260   7  4   9.0   4.9
  9250  17.7  63.9  265   5  2   6.9   3.8 |  17.6  63.7  265   7  3   7.0   3.8
  9000  18.3  64.9  275   5  3   8.3   4.6 |  18.1  64.6  275   6  3   7.4   4.1
  8750  18.9  66.0  280   5  3   9.4   5.2 |  18.7  65.7  285   5  3   8.7   4.8
  8500  19.6  67.3  290   5  3   7.0   3.8 |  19.3  66.7  300   5  3   3.8   2.1
  8250  20.0  68.0  300   5  3   5.2   2.9 |  19.3  66.7  320   5  3  -0.2  -0.1
  8000  20.4  68.7  310   5  3   4.6   2.5 |  19.2  66.6  335   6  3  -0.8  -0.5
  7750  20.6  69.1  320   6  3   2.5   1.4 |  18.9  66.0  350   6  3  -2.6  -1.4
  7500  20.6  69.1  330   6  3  -2.4  -1.3 |  18.8  65.8  360   7  3   4.3   2.4
  7250  20.1  68.2  350   7  3  -6.0  -3.3 |  19.3  66.7  005   6  3   8.3   4.5
  7000  19.7  67.5  005   8  4  -4.8  -2.6 |  19.7  67.5  010   6  3   8.0   4.4
  6750  19.4  66.9  015  10  5  -1.5  -0.8 |  20.3  68.5  010   6  3  10.2   5.6
  6500  19.4  66.9  020   9  5   1.9   1.1 |  21.1  70.0  010   6  3  10.8   5.9
  6250  19.5  67.1  020   8  4   3.1   1.7 |  21.9  71.4  005   6  3  10.9   6.0
  6000  19.6  67.3  025   6  3  -0.0  -0.0 |  22.7  72.9  005   6  3   9.7   5.3
  5750  19.6  67.3  030   3  2   5.4   3.0 |  23.5  74.3  005   6  3  14.8   8.1
  5500  20.6  69.1  020   2  1  23.2  12.7 |  25.1  77.2  010   6  3  27.0  14.8

           08/18/2014 at 1500 MDT          |       08/18/2014 at 1800 MDT
                                           |
K index... +17.2  LI... -3.9               | K index... +24.8  LI... -3.4
CAPE... +1062.7  CIN... -51.0              | CAPE... +812.8  CIN... -28.5
                                           |
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 -61.2 -78.2  285  22 11   1.5   0.8 | -61.4 -78.5  295  22 11   1.3   0.7
 45000 -58.7 -73.7  280  33 17   1.9   1.0 | -58.9 -74.0  285  36 18   2.3   1.3
 40000 -55.3 -67.5  290  48 25   6.7   3.7 | -54.8 -66.6  285  47 24   6.3   3.5
 38000 -51.3 -60.3  290  48 25   6.6   3.6 | -51.0 -59.8  280  45 23   6.3   3.5
 36000 -47.4 -53.3  290  47 24   6.6   3.6 | -47.2 -53.0  280  42 22   6.2   3.4
 34000 -43.0 -45.4  290  42 21   7.5   4.1 | -42.5 -44.5  275  39 20   8.1   4.4
 32000 -38.5 -37.3  290  35 18   7.6   4.1 | -37.7 -35.9  275  36 18   8.0   4.4
 30000 -32.9 -27.2  290  31 16   8.4   4.6 | -32.0 -25.6  275  35 18   8.6   4.7
 29000 -30.4 -22.7  290  31 16   8.4   4.6 | -29.4 -20.9  275  35 18   8.6   4.7
 28000 -27.9 -18.2  290  30 15   8.1   4.4 | -26.9 -16.4  275  35 18   7.9   4.3
 27000 -25.5 -13.9  290  28 15   8.0   4.4 | -24.6 -12.3  275  34 17   7.8   4.3
 26000 -23.1  -9.6  290  27 14   8.0   4.4 | -22.3  -8.1  275  33 17   7.8   4.3
 25000 -20.7  -5.3  290  26 13   7.7   4.2 | -20.0  -4.0  280  32 17   7.6   4.2
 24000 -18.7  -1.7  290  24 13   6.5   3.6 | -18.0  -0.4  280  30 16   6.8   3.7
 23000 -16.8   1.8  290  22 12   6.5   3.6 | -16.0   3.2  285  29 15   6.8   3.7
 22000 -14.8   5.4  285  21 11   6.9   3.8 | -14.0   6.8  290  27 14   6.7   3.7
 21000 -12.6   9.3  290  20 10   7.6   4.1 | -12.0  10.4  290  25 13   6.6   3.6
 20000 -10.4  13.3  295  20 11   7.7   4.2 | -10.1  13.8  290  23 12   6.6   3.6
 19500  -9.3  15.3  300  20 11   7.6   4.2 |  -9.1  15.6  290  21 11   6.4   3.5
 19000  -8.1  17.4  300  20 11   9.5   5.2 |  -8.1  17.4  290  20 10   8.2   4.5
 18500  -6.7  19.9  300  20 10   9.3   5.1 |  -6.9  19.6  290  18  9   8.1   4.5
 18000  -5.4  22.3  305  20 10   9.2   5.0 |  -5.7  21.7  295  17  9   8.3   4.5
 17500  -4.0  24.8  305  20 10   9.1   5.0 |  -4.5  23.9  295  15  8   8.5   4.7
 17000  -2.7  27.1  305  19 10   9.1   5.0 |  -3.2  26.2  295  14  7   8.5   4.7
 16500  -1.4  29.5  305  19 10   9.1   5.0 |  -2.0  28.4  295  12  6   8.9   4.9
 16000  -0.0  32.0  305  18  9   9.1   5.0 |  -0.6  30.9  290  11  5   8.9   4.9
 15500   1.9  35.4  305  16  8   8.4   4.6 |   1.3  34.3  285   8  4   8.8   4.8
 15000   3.2  37.8  300  14  7   8.4   4.6 |   2.7  36.9  280   7  4   8.8   4.8
 14500   4.5  40.1  300  13  6   8.9   4.9 |   4.0  39.2  270   6  3   9.0   4.9
 14000   5.8  42.4  300  11  6   8.9   4.9 |   5.3  41.5  260   6  3   9.0   5.0
 13500   7.1  44.8  295  10  5   9.1   5.0 |   6.7  44.1  245   6  3   8.8   4.8
 13000   8.4  47.1  295   9  4   9.1   5.0 |   8.0  46.4  235   6  3   8.7   4.8
 12500   9.8  49.6  290   7  4   9.0   4.9 |   9.3  48.7  225   6  3   8.6   4.7
 12000  11.1  52.0  285   6  3   8.8   4.9 |  10.5  50.9  220   5  2   8.4   4.6
 11500  12.4  54.3  275   5  3   8.7   4.8 |  11.8  53.2  205   4  2   8.5   4.7
 11000  13.7  56.7  265   5  2   8.2   4.5 |  13.0  55.4  205   4  2   8.5   4.7
 10500  15.0  59.0  250   5  2   4.5   2.5 |  14.2  57.6  205   3  2   4.6   2.5
 10250  15.2  59.4  250   4  2   5.4   3.0 |  14.4  57.9  205   3  2   5.5   3.0
 10000  15.9  60.6  245   4  2  10.9   6.0 |  15.1  59.2  210   3  2  11.6   6.4
  9750  16.6  61.9  245   3  2   9.9   5.4 |  15.9  60.6  220   3  1  10.4   5.7
  9500  17.4  63.3  240   3  1   8.2   4.5 |  16.6  61.9  225   3  1   9.2   5.0
  9250  17.8  64.0  245   1  1   5.8   3.2 |  17.1  62.8  235   3  1   8.0   4.4
  9000  18.2  64.8  010   1  0   6.9   3.8 |  17.8  64.0  240   3  1   9.8   5.4
  8750  18.6  65.5  040   2  1   7.2   3.9 |  18.5  65.3  245   3  1  10.4   5.7
  8500  19.0  66.2  045   4  2   7.8   4.3 |  19.2  66.6  250   3  1   9.7   5.3
  8250  19.5  67.1  045   4  2   8.4   4.6 |  19.9  67.8  255   3  2   8.8   4.8
  8000  20.0  68.0  045   4  2   9.1   5.0 |  20.6  69.1  255   3  2   9.4   5.2
  7750  20.7  69.3  040   4  2   9.7   5.3 |  21.3  70.3  260   3  2   9.9   5.4
  7500  21.4  70.5  040   4  2  10.1   5.6 |  22.0  71.6  265   3  2   9.9   5.5
  7250  22.2  72.0  040   4  2  10.8   5.9 |  22.8  73.0  265   3  2  10.4   5.7
  7000  23.0  73.4  040   4  2  10.2   5.6 |  23.5  74.3  265   4  2   9.7   5.3
  6750  23.7  74.7  040   4  2  10.0   5.5 |  24.2  75.6  265   4  2   9.0   4.9
  6500  24.5  76.1  040   4  2  10.6   5.8 |  24.9  76.8  265   4  2  10.2   5.6
  6250  25.3  77.5  035   4  2  11.7   6.4 |  25.7  78.3  270   4  2  11.3   6.2
  6000  26.1  79.0  035   4  2   9.0   5.0 |  26.5  79.7  270   4  2  10.2   5.6
  5750  26.8  80.2  035   4  2  13.1   7.2 |  27.2  81.0  270   4  2  10.5   5.8
  5500  28.3  82.9  035   4  2  28.1  15.4 |  28.1  82.6  270   4  2  13.9   7.6
________________________________________________________________________________

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.