Soaring Guidance
Issued by NWS Pueblo, CO

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7

000
UXUS97 KPUB 161218
SRGPUB

Soaring Forecast
National Weather Service Pueblo, Colorado
0617 MDT Saturday, September 16, 2017

This forecast is for Saturday, September 16, 2017:

If the trigger temperature of 60.7 F/16.0 C is reached...then
   Thermal Soaring Index....................... Excellent
   Maximum rate of lift........................ 851 ft/min (4.3 m/s)
   Maximum height of thermals.................. 17733 ft MSL (10108 ft AGL)

Forecast maximum temperature................... 69.0 F/21.0 C
Time of trigger temperature.................... 0945 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................. 15095 ft MSL (7471 ft AGL)
Thermal soaring outlook for Sunday 09/17....... Excellent

Wave Soaring Index............................. Not available

Remarks...

Sunrise/Sunset.................... 06:42:03 / 19:05:56 MDT
Total possible sunshine........... 12 hr 23 min 53 sec (743 min 53 sec)
Altitude of sun at 12:54:00 MDT... 53.35 degrees

Upper air data from numerical model forecast valid on 09/16/2017 at 0600 MDT

Freezing level.................. 13152 ft MSL (5527 ft AGL)
Convective condensation level... 14162 ft MSL (6537 ft AGL)
Lifted condensation level....... 15695 ft MSL (8070 ft AGL)
Lifted index.................... -0.7
K index......................... +6.9

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  -59.2 -74.6   230   20   11   2.1   1.2      M     M       M      M    M
 45000  -56.5 -69.7   230   27   14  -0.2  -0.1      M     M       M      M    M
 40000  -56.8 -70.2   230   34   18   3.1   1.7      M     M       M      M    M
 38000  -52.7 -62.9   230   33   17   6.8   3.7      M     M       M      M    M
 36000  -48.6 -55.5   225   32   16   6.8   3.7      M     M       M      M    M
 34000  -44.2 -47.6   230   31   16   7.5   4.1      M     M       M      M    M
 32000  -39.7 -39.5   235   31   16   7.5   4.1      M     M       M      M    M
 30000  -35.1 -31.2   235   30   15   7.7   4.2   33.8  92.8    10.3      M    M
 29000  -32.8 -27.0   235   29   15   7.7   4.2   33.0  91.4     9.8      M    M
 28000  -30.5 -22.9   235   28   14   7.7   4.2   32.3  90.1     9.3      M    M
 27000  -28.2 -18.8   240   27   14   8.0   4.4   31.6  88.8     8.9      M    M
 26000  -25.8 -14.4   240   27   14   8.0   4.4   30.9  87.6     8.4      M    M
 25000  -22.8  -9.0   240   26   14   8.0   4.4   30.2  86.3     7.9      M    M
 24000  -20.5  -4.9   240   26   13   7.2   4.0   29.4  84.8     7.4      M    M
 23000  -18.3  -0.9   240   24   13   7.2   4.0   28.4  83.1     6.6      M    M
 22000  -16.1   3.0   240   23   12   7.3   4.0   27.6  81.6     6.0      M    M
 21000  -14.3   6.3   240   23   12   5.3   2.9   26.3  79.3     4.9      M    M
 20000  -12.8   9.0   240   22   11   5.3   2.9   24.7  76.5     3.6      M    M
 19500  -12.0  10.4   240   22   11   5.3   2.9   24.0  75.2     3.0      M    M
 19000  -11.2  11.8   240   22   11   4.7   2.6   23.3  73.9     2.4      M    M
 18500  -10.7  12.7   240   21   11   3.4   1.9   22.2  72.0     1.4      M    M
 18000  -10.2  13.6   240   21   11   3.4   1.8   21.2  70.1     0.5      M    M
 17500   -9.6  14.7   245   20   10   4.7   2.6   20.2  68.4    -0.4    934  4.7
 17000   -8.9  16.0   245   20   10   4.9   2.7   19.4  66.9    -1.2    899  4.6
 16500   -8.3  17.1   245   20   10   6.4   3.5   18.6  65.4    -2.0    864  4.4
 16000   -7.1  19.2   245   19   10   7.9   4.3   18.3  64.9    -2.4    815  4.1
 15500   -6.0  21.2   240   19   10   8.1   4.5   18.0  64.4    -2.7    766  3.9
 15000   -4.8  23.4   240   18    9   8.5   4.7   17.7  63.9    -3.0    716  3.6
 14500   -3.6  25.5   240   17    9   8.6   4.7   17.5  63.6    -3.3    665  3.4
 14000   -2.4  27.7   235   16    8   8.9   4.9   17.4  63.3    -3.6    613  3.1
 13500   -1.1  30.0   235   15    8   8.8   4.8   17.2  63.0    -3.8    560  2.8
 13000    0.3  32.5   235   14    7  10.7   5.9   17.2  63.0    -3.8    503  2.6
 12500    1.7  35.1   245   13    7   7.2   3.9   17.1  62.7    -4.0    448  2.3
 12000    2.8  37.0   245   13    7   8.8   4.8   16.8  62.2    -4.3    398  2.0
 11750    3.5  38.3   250   13    7   9.3   5.1   16.8  62.2    -4.4    370  1.9
 11500    4.2  39.6   250   12    6   9.4   5.2   16.7  62.1    -4.4    342  1.7
 11250    4.9  40.8   250   12    6   9.5   5.2   16.7  62.1    -4.4    314  1.6
 11000    5.6  42.1   250   12    6   8.4   4.6   16.6  62.0    -4.5    286  1.5
 10750    6.2  43.2   250   12    6   7.7   4.2   16.5  61.7    -4.7    261  1.3
 10500    6.7  44.1   250   12    6   8.5   4.7   16.4  61.5    -4.8    236  1.2
 10250    7.5  45.5   250   12    6  10.7   5.9   16.4  61.4    -4.9    208  1.1
 10000    8.2  46.8   255   11    6   6.5   3.6   16.4  61.4    -4.9    179  0.9
  9750    8.4  47.1   255   10    5   2.8   1.5   15.9  60.6    -5.4    165  0.8
  9500    8.6  47.5   260    9    5   3.0   1.6   15.4  59.7    -6.0    152  0.8
  9250    8.8  47.8   260    8    4   6.2   3.4   14.9  58.8    -6.5    138  0.7
  9000    9.3  48.7   265    7    4   3.8   2.1   14.7  58.5    -6.8    116  0.6
  8750    9.2  48.6   270    5    3  -1.3  -0.7   13.9  57.1    -7.6    112  0.6
  8500    9.1  48.4   280    3    2  -0.2  -0.1   13.2  55.7    -8.5    107  0.5
  8250    9.0  48.2   315    1    1   0.9   0.5   12.4  54.4    -9.3    102  0.5
  8000    9.0  48.2   335    1    1  -0.8  -0.4   11.8  53.2   -10.1     95  0.5
  7750    8.6  47.5   020    1    1  -8.3  -4.5   10.7  51.2   -11.2     99  0.5
  7500      M     M     M    M    M     M     M      M     M       M      M    M
  7250      M     M     M    M    M     M     M      M     M       M      M    M
  7000      M     M     M    M    M     M     M      M     M       M      M    M
  6750      M     M     M    M    M     M     M      M     M       M      M    M

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

           09/16/2017 at 0900 MDT          |       09/16/2017 at 1200 MDT
                                           |
CAPE...   +73.4    LI...       +2.0        | CAPE...   +79.1    LI...       +2.4
CINH...   -39.5    K Index...  +6.3        | CINH...    -5.1    K Index...  +2.6
                                           |
Height Temperature  Wnd WndSpd  Lapse Rate | Temperature  Wnd WndSpd  Lapse Rate
ft MSL deg C deg F  Dir kt m/s  C/km F/kft | deg C deg F  Dir kt m/s  C/km F/kft
--------------------------------------------------------------------------------
 50000 -59.4 -74.9  230  20 10   2.3   1.2 | -59.2 -74.6  225  21 11   2.4   1.3
 45000 -56.5 -69.7  230  27 14  -0.2  -0.1 | -56.2 -69.2  235  27 14  -0.4  -0.2
 40000 -56.9 -70.4  230  33 17   2.4   1.3 | -56.8 -70.2  235  32 17   2.2   1.2
 38000 -53.3 -63.9  225  32 16   5.9   3.3 | -53.5 -64.3  230  31 16   5.5   3.0
 36000 -49.8 -57.6  225  31 16   5.9   3.3 | -50.2 -58.4  225  29 15   5.5   3.0
 34000 -45.3 -49.5  225  31 16   8.3   4.6 | -45.8 -50.4  225  29 15   8.6   4.7
 32000 -40.3 -40.5  230  31 16   8.3   4.6 | -40.6 -41.1  230  30 15   8.6   4.7
 30000 -35.6 -32.1  230  30 16   7.6   4.2 | -35.7 -32.3  235  29 15   8.0   4.4
 29000 -33.3 -27.9  235  30 15   7.6   4.2 | -33.3 -27.9  235  29 15   8.0   4.4
 28000 -31.0 -23.8  235  29 15   7.6   4.2 | -30.9 -23.6  240  28 15   8.0   4.4
 27000 -28.6 -19.5  235  28 15   8.1   4.5 | -28.5 -19.3  245  27 14   8.0   4.4
 26000 -26.1 -15.0  240  28 14   8.2   4.5 | -26.1 -15.0  245  26 14   8.0   4.4
 25000 -23.1  -9.6  240  27 14   8.2   4.5 | -23.1  -9.6  250  25 13   8.0   4.4
 24000 -20.7  -5.3  240  26 13   8.0   4.4 | -20.8  -5.4  250  24 12   7.7   4.2
 23000 -18.3  -0.9  240  24 13   8.0   4.4 | -18.4  -1.1  250  23 12   7.7   4.2
 22000 -15.9   3.4  245  23 12   8.1   4.5 | -16.1   3.0  250  23 12   7.7   4.2
 21000 -13.7   7.3  240  23 12   6.6   3.6 | -13.8   7.2  250  21 11   8.0   4.4
 20000 -11.7  10.9  240  22 11   6.6   3.6 | -11.3  11.7  250  18  9   8.0   4.4
 19500 -10.7  12.7  240  22 11   6.5   3.6 | -10.1  13.8  245  17  9   7.9   4.3
 19000  -9.7  14.5  240  21 11   4.4   2.4 |  -9.0  15.8  245  16  8   6.2   3.4
 18500  -9.4  15.1  240  22 11   1.8   1.0 |  -8.3  17.1  245  17  9   4.8   2.6
 18000  -9.2  15.4  245  22 11   1.9   1.0 |  -7.6  18.3  250  19 10   5.6   3.1
 17500  -9.0  15.8  245  21 11   2.0   1.1 |  -7.4  18.7  255  19 10  -2.1  -1.1
 17000  -8.7  16.3  245  21 11   2.1   1.2 |  -7.7  18.1  255  19 10  -1.0  -0.6
 16500  -8.5  16.7  250  20 10   5.1   2.8 |  -7.8  18.0  260  19 10   2.4   1.3
 16000  -7.4  18.7  250  19 10   7.2   4.0 |  -7.3  18.9  260  18  9   4.4   2.4
 15500  -6.4  20.5  250  18  9   7.5   4.1 |  -6.7  19.9  260  17  9   5.7   3.1
 15000  -5.3  22.5  245  17  9   8.0   4.4 |  -5.6  21.9  260  15  8   9.1   5.0
 14500  -4.2  24.4  245  15  8   8.1   4.4 |  -4.3  24.3  260  13  7   9.0   4.9
 14000  -3.0  26.6  245  14  7   8.5   4.7 |  -3.0  26.6  260  12  6   9.4   5.1
 13500  -1.7  28.9  245  14  7   8.3   4.6 |  -1.6  29.1  260  11  6   9.3   5.1
 13000  -0.4  31.3  250  14  7  10.5   5.7 |  -0.2  31.6  260  10  5  10.3   5.6
 12500   1.0  33.8  250  15  7   7.6   4.2 |   1.2  34.2  255  10  5   8.6   4.7
 12000   2.2  36.0  250  14  7   8.4   4.6 |   2.6  36.7  255   9  5   9.3   5.1
 11750   2.8  37.0  250  14  7   8.4   4.6 |   3.2  37.8  255   9  5   9.3   5.1
 11500   3.5  38.3  250  13  7   9.7   5.3 |   4.0  39.2  255   9  4  10.4   5.7
 11250   4.2  39.6  250  13  7  10.2   5.6 |   4.8  40.6  250   8  4  10.4   5.7
 11000   4.9  40.8  250  12  6   8.3   4.5 |   5.5  41.9  250   8  4   8.6   4.7
 10750   5.5  41.9  250  12  6   7.5   4.1 |   6.1  43.0  250   8  4   7.8   4.3
 10500   6.1  43.0  250  11  6   8.6   4.7 |   6.7  44.1  245   7  4   9.3   5.1
 10250   6.8  44.2  245  11  6  10.2   5.6 |   7.5  45.5  240   7  4  11.7   6.4
 10000   7.5  45.5  245  10  5   7.9   4.3 |   8.3  46.9  240   7  3  10.5   5.8
  9750   7.9  46.2  245  10  5   6.1   3.3 |   9.0  48.2  235   6  3   9.2   5.1
  9500   8.4  47.1  245   9  5   5.9   3.3 |   9.7  49.5  235   6  3   9.4   5.1
  9250   8.8  47.8  245   9  5   8.4   4.6 |  10.4  50.7  230   6  3  10.1   5.5
  9000   9.5  49.1  240   8  4   6.1   3.4 |  11.2  52.2  230   6  3  10.3   5.6
  8750   9.6  49.3  235   7  4   2.2   1.2 |  11.9  53.4  225   6  3   9.8   5.4
  8500   9.7  49.5  230   6  3   2.7   1.5 |  12.7  54.9  225   6  3   9.5   5.2
  8250   9.9  49.8  220   4  2   5.1   2.8 |  13.4  56.1  220   5  3  11.1   6.1
  8000  10.5  50.9  205   4  2  12.8   7.0 |  14.5  58.1  220   5  3  18.8  10.3
  7750  11.7  53.1  190   3  2  17.1   9.4 |  16.2  61.2  220   5  3  26.5  14.5
  7500     M     M    M   M  M     M     M |     M     M    M   M  M     M     M
  7250     M     M    M   M  M     M     M |     M     M    M   M  M     M     M
  7000     M     M    M   M  M     M     M |     M     M    M   M  M     M     M
  6750     M     M    M   M  M     M     M |     M     M    M   M  M     M     M

           09/16/2017 at 1500 MDT          |       09/16/2017 at 1800 MDT
                                           |
CAPE...   +61.5    LI...       +0.8        | CAPE...   +65.9    LI...       -0.7
CINH...   -10.0    K Index... +15.2        | CINH...   -16.1    K Index... +21.3
                                           |
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 -58.9 -74.0  230  23 12   2.0   1.1 | -59.4 -74.9  230  22 11   2.2   1.2
 45000 -56.5 -69.7  235  28 14  -0.5  -0.3 | -56.8 -70.2  240  26 13  -0.4  -0.2
 40000 -57.3 -71.1  240  30 15   2.4   1.3 | -57.5 -71.5  245  24 12   2.8   1.5
 38000 -53.9 -65.0  240  29 15   5.6   3.1 | -54.2 -65.6  250  24 12   5.4   3.0
 36000 -50.5 -58.9  240  29 15   5.6   3.1 | -51.0 -59.8  255  23 12   5.4   3.0
 34000 -46.2 -51.2  240  29 15   8.1   4.4 | -46.5 -51.7  255  23 12   8.6   4.7
 32000 -41.4 -42.5  245  27 14   8.1   4.4 | -41.3 -42.3  260  23 12   8.6   4.7
 30000 -36.5 -33.7  245  26 13   8.2   4.5 | -36.2 -33.2  260  22 11   8.4   4.6
 29000 -34.0 -29.2  250  25 13   8.2   4.5 | -33.6 -28.5  260  21 11   8.4   4.6
 28000 -31.6 -24.9  250  24 12   8.2   4.5 | -31.1 -24.0  260  20 10   8.5   4.6
 27000 -29.0 -20.2  255  23 12   8.5   4.7 | -28.6 -19.5  255  19 10   8.3   4.5
 26000 -26.5 -15.7  255  22 11   8.5   4.7 | -26.1 -15.0  255  19 10   8.3   4.5
 25000 -23.9 -11.0  255  21 11   8.5   4.7 | -23.6 -10.5  250  19 10   8.3   4.5
 24000 -20.8  -5.4  250  20 10   8.0   4.4 | -20.7  -5.3  250  18 10   7.6   4.2
 23000 -18.4  -1.1  250  20 10   8.0   4.4 | -18.4  -1.1  250  19 10   7.6   4.2
 22000 -16.0   3.2  245  19 10   8.2   4.5 | -16.1   3.0  245  19 10   7.9   4.3
 21000 -14.0   6.8  245  19 10   6.4   3.5 | -14.4   6.1  250  19 10   5.2   2.8
 20000 -12.0  10.4  250  18  9   6.4   3.5 | -12.8   9.0  250  18  9   5.2   2.9
 19500 -11.1  12.0  250  17  9   6.4   3.5 | -12.1  10.2  250  18  9   5.3   2.9
 19000 -10.2  13.6  250  17  9   4.1   2.2 | -11.3  11.7  250  18  9   3.9   2.1
 18500  -9.8  14.4  250  15  8   3.0   1.6 | -10.9  12.4  250  16  8   3.6   2.0
 18000  -9.4  15.1  250  14  7   3.4   1.8 | -10.4  13.3  245  15  8   4.3   2.4
 17500  -8.9  16.0  250  13  7   3.8   2.1 |  -9.5  14.9  245  14  7   8.2   4.5
 17000  -8.5  16.7  255  13  7   4.0   2.2 |  -8.4  16.9  245  13  7   8.1   4.4
 16500  -7.9  17.8  260  13  6   7.4   4.0 |  -7.3  18.9  245  12  6   8.9   4.9
 16000  -6.7  19.9  260  11  6   8.3   4.6 |  -6.0  21.2  245  11  6   9.0   4.9
 15500  -5.5  22.1  260  10  5   8.7   4.8 |  -4.7  23.5  245   9  5   9.3   5.1
 15000  -4.2  24.4  260   9  5   9.1   5.0 |  -3.3  26.1  245   9  4   9.5   5.2
 14500  -2.8  27.0  260   9  4   9.2   5.0 |  -1.9  28.6  245   8  4   9.5   5.2
 14000  -1.4  29.5  260   8  4   9.7   5.3 |  -0.4  31.3  245   7  4   9.5   5.2
 13500   0.0  32.0  260   8  4   9.4   5.2 |   1.0  33.8  250   7  3   9.5   5.2
 13000   1.6  34.9  260   7  4  11.5   6.3 |   2.4  36.3  250   6  3  10.1   5.5
 12500   3.0  37.4  255   6  3   8.2   4.5 |   3.8  38.8  250   5  3   8.6   4.7
 12000   4.3  39.7  250   6  3   8.8   4.8 |   5.1  41.2  250   4  2   8.8   4.8
 11750   4.9  40.8  250   5  3   8.9   4.9 |   5.7  42.3  250   4  2   8.8   4.9
 11500   5.6  42.1  245   5  3  10.1   5.5 |   6.4  43.5  245   3  2   9.2   5.1
 11250   6.4  43.5  245   5  2  10.1   5.6 |   7.1  44.8  245   3  2   9.1   5.0
 11000   7.1  44.8  245   5  2   8.9   4.9 |   7.8  46.0  245   3  1   8.7   4.8
 10750   7.7  45.9  240   4  2   8.4   4.6 |   8.4  47.1  235   2  1   8.3   4.6
 10500   8.4  47.1  235   4  2   9.7   5.3 |   9.0  48.2  230   2  1   9.7   5.3
 10250   9.2  48.6  235   4  2  11.3   6.2 |   9.8  49.6  220   2  1  10.8   5.9
 10000  10.0  50.0  235   4  2   9.9   5.4 |  10.6  51.1  215   2  1   9.4   5.2
  9750  10.7  51.3  230   4  2   9.2   5.1 |  11.2  52.2  205   2  1   8.9   4.9
  9500  11.4  52.5  230   4  2   9.0   4.9 |  11.9  53.4  190   1  1   9.4   5.1
  9250  12.1  53.8  225   4  2  10.6   5.8 |  12.6  54.7  180   1  1   7.9   4.4
  9000  12.9  55.2  225   4  2  11.0   6.0 |  13.1  55.6  175   2  1   8.6   4.7
  8750  13.6  56.5  225   3  2   9.7   5.3 |  13.9  57.0  165   2  1  10.4   5.7
  8500  14.4  57.9  220   3  2   9.7   5.3 |  14.6  58.3  155   2  1   9.9   5.4
  8250  15.1  59.2  220   3  2  10.8   5.9 |  15.4  59.7  145   2  1  10.3   5.7
  8000  16.1  61.0  215   3  2  14.1   7.7 |  16.2  61.2  145   2  1  10.8   5.9
  7750  17.2  63.0  215   3  2  15.8   8.7 |  16.9  62.4  135   2  1  10.7   5.9
  7500     M     M    M   M  M     M     M |     M     M    M   M  M     M     M
  7250     M     M    M   M  M     M     M |     M     M    M   M  M     M     M
  7000     M     M    M   M  M     M     M |     M     M    M   M  M     M     M
  6750     M     M    M   M  M     M     M |     M     M    M   M  M     M     M
________________________________________________________________________________

This product is issued twice per day, once by approximately 0630 MST/0730 MDT
(1330 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 Air Force Academy
in Colorado Springs, Colorado at

                   North Latitude:  38 deg 58 min 48.000 sec
                   West Longitude: 104 deg 49 min 12.000 sec
                   Elevation: 6572 feet (2003 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.