Soaring Guidance
Issued by NWS Denver/Boulder, CO

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14

000
UXUS97 KBOU 260022
SRGBOU

Soaring Forecast
National Weather Service Denver/Boulder, Colorado
1821 MDT Thursday, August 25, 2016

This forecast is for Friday, August 26, 2016:

If the trigger temperature of 69.9 F/21.1 C is reached...then
   Thermal Soaring Index....................... Good
   Maximum rate of lift........................ 467 ft/min (2.4 m/s)
   Maximum height of thermals.................. 13365 ft MSL (8058 ft AGL)

Forecast maximum temperature................... 76.0 F/24.9 C
Time of trigger temperature.................... 1130 MDT
Time of overdevelopment........................ None
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................. 10033 ft MSL (4727 ft AGL)
Thermal soaring outlook for Saturday 08/27..... Fair

Wave Soaring Index............................. Poor
Wave Soaring Index trend (to 1800 MDT)......... Slightly better.
Height of stable layer (12-18K ft MSL)......... None
Weak PVA/NVA (through 1800 MDT)................ Neither
Potential height of wave....................... 39726 ft MSL (34419 ft AGL)
Wave soaring outlook for Saturday 08/27........ Poor

Remarks...

Sunrise/Sunset.................... 06:22:23 / 19:40:26 MDT
Total possible sunshine........... 13 hr 18 min 3 sec (798 min 3 sec)
Altitude of sun at 13:00:59 MDT... 60.28 degrees

Upper air data from numerical model forecast valid on 08/26/2016 at 0600 MDT

Freezing level.................. 13530 ft MSL (8223 ft AGL)
Convective condensation level... 11444 ft MSL (6137 ft AGL)
Lifted condensation level....... 12276 ft MSL (6969 ft AGL)
Lifted index.................... -2.6
K index......................... +25.6

Height  Temperature  Wind  Wind Spd  Lapse Rate  ConvectionT  Thermal  Lift Rate
ft MSL  deg C deg F   Dir   kt  m/s  C/km F/kft  deg C deg F   Index    fpm  m/s
--------------------------------------------------------------------------------
 50000  -59.3 -74.7   240   35   18   1.4   0.8      M     M       M      M    M
 45000  -57.6 -71.7   240   50   26  -0.5  -0.2      M     M       M      M    M
 40000  -58.3 -72.9   235   57   29   2.4   1.3      M     M       M      M    M
 38000  -54.9 -66.8   235   59   30   5.7   3.1      M     M       M      M    M
 36000  -51.4 -60.5   230   61   31   5.7   3.1      M     M       M      M    M
 34000  -46.7 -52.1   230   57   29   9.2   5.1      M     M       M      M    M
 32000  -41.2 -42.2   230   49   25   9.2   5.1      M     M       M      M    M
 30000  -34.9 -30.8   230   42   22   9.4   5.1   40.6 105.1    12.2      M    M
 29000  -32.1 -25.8   230   40   20   9.4   5.1   40.5 104.9    12.3      M    M
 28000  -29.3 -20.7   225   37   19   9.3   5.1   40.5 104.9    12.4      M    M
 27000  -27.0 -16.6   225   35   18   7.4   4.1   39.7 103.4    11.9      M    M
 26000  -24.8 -12.6   225   32   17   7.4   4.1   38.7 101.7    11.2      M    M
 25000  -22.6  -8.7   225   30   15   7.5   4.1   38.0 100.3    10.7      M    M
 24000  -20.5  -4.9   230   28   14   7.1   3.9   37.0  98.6    10.0      M    M
 23000  -18.4  -1.1   230   26   14   7.1   3.9   36.0  96.8     9.3      M    M
 22000  -16.3   2.7   235   25   13   7.2   4.0   35.1  95.3     8.6      M    M
 21000  -14.3   6.3   240   23   12   6.4   3.5   34.0  93.2     7.7      M    M
 20000  -12.5   9.5   245   20   10   6.4   3.5   32.8  91.0     6.7      M    M
 19500  -11.6  11.1   245   19   10   6.4   3.5   32.2  90.0     6.3      M    M
 19000  -10.6  12.9   250   18    9   6.6   3.6   31.7  89.0     5.8      M    M
 18500   -9.6  14.7   250   16    8   6.8   3.7   31.2  88.1     5.3      M    M
 18000   -8.7  16.3   255   15    8   6.9   3.8   30.6  87.2     4.9      M    M
 17500   -7.7  18.1   255   13    7   5.9   3.2   30.1  86.1     4.4      M    M
 17000   -6.9  19.6   255   12    6   5.9   3.2   29.4  84.9     3.8      M    M
 16500   -6.0  21.2   260   10    5   5.9   3.3   28.8  83.8     3.2      M    M
 16000   -4.7  23.5   260    8    4   5.9   3.3   27.8  82.1     2.4      M    M
 15500   -3.8  25.2   260    7    4   6.8   3.7   27.2  81.0     1.8      M    M
 15000   -2.8  27.0   255    7    3   7.1   3.9   26.8  80.2     1.4      M    M
 14500   -1.8  28.8   250    6    3   7.0   3.8   26.3  79.4     1.0      M    M
 14000   -0.8  30.6   245    5    3   6.8   3.7   25.8  78.5     0.5      M    M
 13500    0.2  32.4   235    5    2   6.7   3.7   25.4  77.7     0.1      M    M
 13000    1.1  34.0   235    4    2   6.2   3.4   24.8  76.7    -0.5    629  3.2
 12500    2.0  35.6   240    4    2   6.3   3.5   24.3  75.7    -1.0    587  3.0
 12000    3.1  37.6   245    5    2   7.5   4.1   23.8  74.9    -1.5    542  2.8
 11500    4.1  39.4   250    5    3   7.4   4.0   23.4  74.2    -1.9    495  2.5
 11000    5.3  41.5   245    6    3   8.2   4.5   23.1  73.6    -2.2    446  2.3
 10500    6.5  43.7   240    8    4   7.2   4.0   22.9  73.2    -2.4    394  2.0
 10250    6.9  44.4   235    8    4   4.7   2.6   22.6  72.7    -2.7    374  1.9
 10000    7.3  45.1   235    9    5   7.7   4.2   22.3  72.1    -3.1    355  1.8
  9750    8.0  46.4   230   11    5  10.5   5.8   22.3  72.1    -3.1    326  1.7
  9500    8.8  47.8   230   12    6   9.4   5.2   22.3  72.1    -3.1    298  1.5
  9250    9.4  48.9   225   13    7   6.3   3.4   22.2  71.9    -3.3    272  1.4
  9000    9.7  49.5   225   14    7   6.4   3.5   21.8  71.3    -3.6    254  1.3
  8750   10.3  50.5   225   14    7   8.8   4.8   21.7  71.1    -3.8    229  1.2
  8500   10.9  51.6   225   14    7   7.9   4.3   21.6  70.9    -3.9    204  1.0
  8250   11.4  52.5   225   15    8   7.5   4.1   21.4  70.6    -4.2    181  0.9
  8000   11.9  53.4   220   15    8   7.0   3.8   21.3  70.3    -4.4    159  0.8
  7750   12.3  54.1   220   15    8   6.4   3.5   21.0  69.8    -4.7    139  0.7
  7500   12.8  55.0   215   15    8   6.2   3.4   20.7  69.3    -5.0    119  0.6
  7250   13.2  55.8   210   16    8   6.2   3.4   20.5  68.8    -5.4     99  0.5
  7000   13.6  56.5   210   17    9   6.3   3.4   20.2  68.4    -5.7     79  0.4
  6750   14.0  57.2   205   18    9   5.8   3.2   19.9  67.9    -6.0     59  0.3
  6500   14.4  57.9   200   18    9   3.8   2.1   19.6  67.2    -6.4     41  0.2
  6250   14.5  58.1   195   16    8   3.0   1.6   19.0  66.3    -7.0     29  0.1
  6000   14.7  58.5   190   15    7   2.5   1.4   18.5  65.4    -7.6     17  0.1
  5750   14.8  58.6   185   13    7   2.3   1.3   18.0  64.3    -8.2      7  0.0
  5500   15.0  59.0   175    9    5   5.7   3.1   17.5  63.6    -8.7      M    M

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

           08/26/2016 at 0900 MDT          |       08/26/2016 at 1200 MDT
                                           |
K index... +25.7  LI... -2.9               | K index... +16.9  LI... -1.2
CAPE... +528.8  CIN... -25.7               | CAPE... +183.0  CIN... -32.1
                                           |
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 -58.6 -73.5  240  33 17   1.7   0.9 | -58.8 -73.8  235  33 17   1.5   0.8
 45000 -57.0 -70.6  235  46 24  -1.8  -1.0 | -57.1 -70.8  235  43 22  -0.6  -0.4
 40000 -59.7 -75.5  215  63 32   2.2   1.2 | -58.0 -72.4  210  53 28   2.6   1.4
 38000 -55.4 -67.7  215  58 30   7.3   4.0 | -54.1 -65.4  200  58 30   6.7   3.7
 36000 -51.0 -59.8  215  54 28   7.3   4.0 | -50.1 -58.2  195  63 33   6.7   3.7
 34000 -46.0 -50.8  215  49 25   9.2   5.1 | -45.5 -49.9  200  55 28   8.3   4.5
 32000 -40.4 -40.7  220  44 23   9.2   5.1 | -39.9 -39.8  205  36 19   8.3   4.6
 30000 -34.4 -29.9  220  36 19   8.9   4.9 | -34.7 -30.5  215  28 14   8.8   4.8
 29000 -31.7 -25.1  220  33 17   8.9   4.9 | -32.1 -25.8  220  25 13   8.8   4.8
 28000 -29.1 -20.4  225  29 15   9.0   4.9 | -29.5 -21.1  225  23 12   8.9   4.9
 27000 -26.7 -16.1  220  27 14   7.7   4.2 | -27.2 -17.0  230  22 11   7.4   4.0
 26000 -24.4 -11.9  220  26 13   7.7   4.2 | -25.0 -13.0  235  22 11   7.4   4.0
 25000 -22.2  -8.0  220  25 13   7.7   4.2 | -22.8  -9.0  240  22 11   7.4   4.1
 24000 -20.1  -4.2  225  24 12   6.5   3.5 | -20.7  -5.3  245  21 11   7.0   3.8
 23000 -18.2  -0.8  230  23 12   6.4   3.5 | -18.6  -1.5  250  20 10   7.0   3.8
 22000 -16.3   2.7  240  22 11   6.5   3.6 | -16.5   2.3  260  19 10   7.0   3.8
 21000 -14.5   5.9  245  20 10   5.7   3.1 | -14.6   5.7  265  18  9   6.5   3.6
 20000 -12.9   8.8  255  17  9   5.7   3.1 | -12.6   9.3  270  16  8   6.5   3.6
 19500 -12.0  10.4  260  16  8   5.7   3.1 | -11.7  10.9  275  15  8   6.5   3.5
 19000 -11.2  11.8  265  15  8   5.6   3.1 | -10.7  12.7  280  14  7   5.3   2.9
 18500 -10.4  13.3  270  13  7   5.5   3.0 | -10.2  13.6  290  13  7   3.1   1.7
 18000  -9.6  14.7  275  11  6   5.5   3.0 |  -9.8  14.4  300  12  6   3.0   1.6
 17500  -8.8  16.2  280  10  5   5.5   3.0 |  -9.2  15.4  310  12  6   5.0   2.8
 17000  -8.0  17.6  290   9  5   5.6   3.1 |  -8.4  16.9  325  13  7   5.2   2.8
 16500  -7.2  19.0  305   9  5   6.0   3.3 |  -7.0  19.4  335  15  8   8.3   4.6
 16000  -5.8  21.6  315  10  5   6.5   3.6 |  -5.8  21.6  335  17  9   8.1   4.4
 15500  -4.9  23.2  320  11  6   6.5   3.5 |  -4.7  23.5  340  18  9   7.8   4.3
 15000  -3.9  25.0  325  11  6   6.5   3.6 |  -3.6  25.5  340  19 10   7.7   4.2
 14500  -3.0  26.6  330  11  6   7.0   3.8 |  -2.5  27.5  340  19 10   7.8   4.3
 14000  -1.9  28.6  335  11  6   7.8   4.3 |  -1.3  29.7  340  19 10   7.8   4.3
 13500  -0.7  30.7  340  11  5   7.8   4.3 |  -0.2  31.6  345  19 10   7.9   4.3
 13000   0.4  32.7  340  10  5   7.9   4.3 |   1.0  33.8  345  19 10   8.6   4.7
 12500   1.6  34.9  345   9  5   7.9   4.3 |   2.2  36.0  345  18  9   8.6   4.7
 12000   2.7  36.9  345   8  4   7.5   4.1 |   3.4  38.1  350  17  9   8.5   4.7
 11500   3.8  38.8  345   7  4   7.5   4.1 |   4.7  40.5  350  15  8   8.6   4.7
 11000   5.0  41.0  345   7  3   8.7   4.8 |   5.8  42.4  350  14  7   7.6   4.2
 10500   6.2  43.2  340   6  3   7.8   4.3 |   6.9  44.4  345  13  6   6.4   3.5
 10250   6.7  44.1  335   5  3   4.6   2.5 |   7.3  45.1  345  12  6   4.1   2.3
 10000   7.1  44.8  330   5  3   6.9   3.8 |   7.6  45.7  345  12  6   7.6   4.1
  9750   7.7  45.9  325   5  3  10.0   5.5 |   8.3  46.9  345  11  6  10.1   5.6
  9500   8.4  47.1  320   5  3   8.8   4.8 |   9.0  48.2  340  11  6   9.0   4.9
  9250   9.0  48.2  320   5  3   5.8   3.2 |   9.6  49.3  340  10  5   6.2   3.4
  9000   9.3  48.7  315   5  3   5.8   3.2 |  10.0  50.0  340  10  5   5.8   3.2
  8750   9.8  49.6  310   5  3   7.9   4.3 |  10.5  50.9  340   9  5   7.3   4.0
  8500  10.4  50.7  310   5  3   7.1   3.9 |  11.0  51.8  340   9  5   6.8   3.7
  8250  10.9  51.6  305   6  3   6.9   3.8 |  11.4  52.5  340   8  4   6.3   3.4
  8000  11.3  52.3  300   6  3   6.4   3.5 |  11.8  53.2  340   7  3   7.1   3.9
  7750  11.8  53.2  300   7  3   5.5   3.0 |  12.3  54.1  345   6  3   8.5   4.7
  7500  12.1  53.8  300   7  4   6.0   3.3 |  12.9  55.2  345   5  3   9.4   5.1
  7250  12.6  54.7  285   6  3   6.9   3.8 |  13.6  56.5  345   5  3   9.9   5.4
  7000  13.0  55.4  270   6  3   6.7   3.7 |  14.4  57.9  345   5  3   9.9   5.4
  6750  13.5  56.3  250   6  3   6.4   3.5 |  15.1  59.2  345   5  3  10.5   5.7
  6500  13.9  57.0  230   6  3   7.5   4.1 |  15.9  60.6  345   5  3  10.8   5.9
  6250  14.4  57.9  225   5  3   8.5   4.7 |  16.7  62.1  345   5  3  11.2   6.1
  6000  15.0  59.0  210   4  2   7.8   4.3 |  17.5  63.5  345   5  2   9.6   5.3
  5750  15.5  59.9  190   4  2  10.6   5.8 |  18.3  64.9  345   5  2  14.0   7.7
  5500  16.5  61.7  190   3  2  16.8   9.2 |  19.8  67.6  345   5  2  26.6  14.6

           08/26/2016 at 1500 MDT          |       08/26/2016 at 1800 MDT
                                           |
K index... +24.0  LI... -2.5               | K index... +28.0  LI... -2.8
CAPE... +345.9  CIN... -14.1               | CAPE... +394.2  CIN... -10.3
                                           |
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 -59.1 -74.4  235  35 18   1.4   0.8 | -59.1 -74.4  240  37 19   1.7   0.9
 45000 -57.0 -70.6  240  42 22   1.0   0.6 | -56.6 -69.9  245  42 22   1.2   0.7
 40000 -55.5 -67.9  225  41 21   2.7   1.5 | -54.8 -66.6  245  33 17   2.7   1.5
 38000 -52.6 -62.7  220  42 21   4.8   2.6 | -52.1 -61.8  240  36 19   4.4   2.4
 36000 -49.7 -57.5  215  42 22   4.8   2.6 | -49.5 -57.1  240  39 20   4.4   2.4
 34000 -45.7 -50.3  220  40 21   8.0   4.4 | -45.7 -50.3  240  40 20   7.4   4.1
 32000 -40.3 -40.5  220  37 19   8.1   4.4 | -40.7 -41.3  240  38 20   7.5   4.1
 30000 -35.4 -31.7  225  32 17   8.1   4.5 | -36.0 -32.8  245  34 17   8.2   4.5
 29000 -33.0 -27.4  225  30 15   8.1   4.5 | -33.5 -28.3  245  31 16   8.2   4.5
 28000 -30.6 -23.1  225  27 14   8.2   4.5 | -31.0 -23.8  250  28 15   8.3   4.5
 27000 -28.3 -18.9  230  25 13   7.6   4.2 | -28.7 -19.7  250  26 14   8.0   4.4
 26000 -26.0 -14.8  240  23 12   7.7   4.2 | -26.3 -15.3  255  24 13   8.0   4.4
 25000 -23.7 -10.7  250  22 11   7.7   4.2 | -23.9 -11.0  260  23 12   8.0   4.4
 24000 -21.5  -6.7  255  22 11   7.3   4.0 | -21.6  -6.9  270  21 11   7.4   4.0
 23000 -19.3  -2.7  265  21 11   7.3   4.0 | -19.4  -2.9  275  20 10   7.3   4.0
 22000 -17.2   1.0  270  22 11   7.4   4.1 | -17.2   1.0  285  20 10   7.4   4.1
 21000 -15.2   4.6  275  23 12   6.1   3.3 | -15.3   4.5  290  21 11   6.0   3.3
 20000 -13.4   7.9  285  24 12   6.1   3.3 | -13.5   7.7  295  23 12   6.0   3.3
 19500 -12.4   9.7  290  25 13   6.1   3.3 | -12.6   9.3  295  24 12   6.1   3.3
 19000 -11.5  11.3  290  26 13   6.3   3.5 | -11.7  10.9  300  25 13   6.7   3.7
 18500 -10.5  13.1  295  26 14   6.7   3.7 | -10.6  12.9  300  26 13   7.7   4.2
 18000  -9.6  14.7  295  27 14   6.7   3.7 |  -9.5  14.9  300  26 13   7.8   4.3
 17500  -8.5  16.7  295  27 14   7.3   4.0 |  -8.4  16.9  300  26 14   7.8   4.3
 17000  -7.5  18.5  300  27 14   7.4   4.0 |  -7.3  18.9  300  26 14   7.8   4.3
 16500  -5.9  21.4  300  26 14   7.8   4.3 |  -5.6  21.9  300  26 13   8.2   4.5
 16000  -4.8  23.4  305  26 13   7.8   4.3 |  -4.4  24.1  295  25 13   8.2   4.5
 15500  -3.6  25.5  305  25 13   7.6   4.2 |  -3.2  26.2  295  24 12   8.2   4.5
 15000  -2.6  27.3  305  24 12   7.6   4.1 |  -2.1  28.2  295  22 11   8.2   4.5
 14500  -1.5  29.3  310  22 12   7.5   4.1 |  -0.9  30.4  295  19 10   7.5   4.1
 14000  -0.5  31.1  310  20 10   7.4   4.0 |  -0.0  32.0  290  15  8   6.6   3.6
 13500   0.6  33.1  315  18  9   7.5   4.1 |   0.9  33.6  285  11  6   6.5   3.6
 13000   1.7  35.1  315  16  8   7.9   4.3 |   1.8  35.2  275   7  3   6.2   3.4
 12500   2.9  37.2  320  14  7   7.8   4.3 |   2.6  36.7  245   3  2   6.3   3.5
 12000   4.0  39.2  325  12  6   7.3   4.0 |   3.8  38.8  195   2  1   9.1   5.0
 11500   5.1  41.2  330  10  5   7.4   4.0 |   5.1  41.2  170   3  1   8.8   4.9
 11000   6.2  43.2  340   7  4   8.4   4.6 |   6.4  43.5  160   3  1   9.2   5.1
 10500   7.4  45.3  360   5  2   6.2   3.4 |   7.8  46.0  150   3  1   6.4   3.5
 10250   7.8  46.0  010   4  2   5.6   3.1 |   8.2  46.8  150   3  1   6.4   3.5
 10000   8.3  46.9  015   4  2  10.0   5.5 |   8.9  48.0  145   3  1  11.5   6.3
  9750   9.1  48.4  025   3  2  10.9   6.0 |   9.7  49.5  145   3  1  11.5   6.3
  9500   9.8  49.6  030   3  2  10.3   5.7 |  10.6  51.1  140   3  1  11.1   6.1
  9250  10.5  50.9  040   3  1   8.5   4.7 |  11.3  52.3  140   3  1   8.9   4.9
  9000  11.1  52.0  040   3  2   9.7   5.3 |  12.0  53.6  140   3  1   9.1   5.0
  8750  11.9  53.4  040   3  1  11.8   6.5 |  12.7  54.9  135   3  1  10.5   5.8
  8500  12.8  55.0  040   3  1  10.7   5.9 |  13.5  56.3  135   3  1  10.1   5.5
  8250  13.5  56.3  040   3  1   9.6   5.3 |  14.2  57.6  130   3  1  10.1   5.6
  8000  14.2  57.6  040   3  1   9.5   5.2 |  15.0  59.0  130   3  1  10.1   5.6
  7750  15.0  59.0  045   3  1  10.0   5.5 |  15.8  60.4  125   3  1  10.3   5.6
  7500  15.7  60.3  045   3  1  10.1   5.5 |  16.5  61.7  125   3  1  10.1   5.5
  7250  16.5  61.7  045   3  1  10.2   5.6 |  17.3  63.1  120   3  1   9.8   5.4
  7000  17.2  63.0  045   3  1  10.2   5.6 |  18.0  64.4  120   3  1   9.8   5.4
  6750  18.0  64.4  045   3  1  10.6   5.8 |  18.7  65.7  115   3  1   9.8   5.4
  6500  18.8  65.8  045   3  1  10.6   5.8 |  19.5  67.1  115   3  1  10.1   5.5
  6250  19.6  67.3  045   3  1  10.9   6.0 |  20.2  68.4  110   3  1  10.5   5.8
  6000  20.4  68.7  045   2  1   9.5   5.2 |  21.0  69.8  110   2  1   9.7   5.3
  5750  21.2  70.2  045   2  1  14.5   7.9 |  21.7  71.1  105   2  1  11.2   6.1
  5500  22.7  72.9  050   2  1  28.5  15.6 |  22.8  73.0  105   3  1  17.2   9.4
________________________________________________________________________________

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.