Soaring Guidance
Issued by NWS Grand Junction, CO

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7
000
UXUS97 KGJT 191223
SRGGJT

Soaring Forecast
National Weather Service Grand Junction, Colorado
0623 MDT Friday, August 19, 2016

This forecast is for Friday, August 19, 2016:

If the trigger temperature of 79.1 F/26.1 C is reached...then
   Thermal Soaring Index....................... Excellent
   Maximum rate of lift........................ 863 ft/min (4.4 m/s)
   Maximum height of thermals.................. 18631 ft MSL (13792 ft AGL)

Forecast maximum temperature................... 90.0 F/32.7 C
Time of trigger temperature.................... 1100 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................. 14603 ft MSL (9763 ft AGL)
Thermal soaring outlook for Saturday 08/20..... Good

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

Remarks...

Sunrise/Sunset.................... 06:31:30 / 20:04:13 MDT
Total possible sunshine........... 13 hr 32 min 42 sec (812 min 42 sec)
Altitude of sun at 13:17:29 MDT... 63.31 degrees

Upper air data from rawinsonde observation taken on 08/19/2016 at 0600 MDT

Freezing level.................. 14450 ft MSL (9611 ft AGL)
Convective condensation level... 14351 ft MSL (9512 ft AGL)
Lifted condensation level....... 15819 ft MSL (10980 ft AGL)
Lifted index.................... -3.1
K index......................... +24.8

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  -58.8 -73.8   260   31   16   1.1   0.6   97.2 207.0    37.6      M    M
 45000  -55.1 -67.2   250   36   19   4.8   2.6   78.8 173.9    28.9      M    M
 40000  -57.4 -71.3   245   24   12   0.5   0.3   52.3 126.2    13.4      M    M
 38000  -54.0 -65.2   285   29   15   7.6   4.1   48.8 119.8    11.3      M    M
 36000  -48.7 -55.7   275   34   18   8.9   4.9   47.9 118.3    11.0      M    M
 34000  -43.0 -45.4   270   31   16   8.9   4.9   46.7 116.1    10.4      M    M
 32000  -37.8 -36.0   265   24   12   7.7   4.2   46.0 114.7    10.1      M    M
 30000  -33.1 -27.6   265   21   11   8.0   4.4   44.4 111.9     9.2      M    M
 29000  -30.4 -22.7   280   19   10   8.7   4.8   44.1 111.4     9.0      M    M
 28000  -28.0 -18.4   290   19   10   6.6   3.6   43.4 110.2     8.6      M    M
 27000  -26.5 -15.7   305   19   10   1.9   1.0   41.5 106.7     7.3      M    M
 26000  -24.0 -11.2   300   17    9   8.8   4.8   40.9 105.6     6.8      M    M
 25000  -21.4  -6.5   295   15    8   6.2   3.4   40.6 105.0     6.6      M    M
 24000  -19.2  -2.6   280   14    7   7.7   4.2   39.8 103.6     6.0      M    M
 23000  -17.1   1.2   295   11    6   9.4   5.2   38.7 101.7     5.2      M    M
 22000  -14.3   6.3   285    8    4   9.0   5.0   38.6 101.4     5.2      M    M
 21000  -12.8   9.0   285   10    5   5.0   2.7   37.0  98.6     3.8      M    M
 20000  -11.1  12.0   305   11    6   3.0   1.6   35.6  96.0     2.6      M    M
 19500  -10.5  13.1   315   11    6   4.5   2.5   34.5  94.2     1.7      M    M
 19000  -10.1  13.8   330   11    6   3.3   1.8   33.4  92.1     0.7      M    M
 18500   -8.8  16.2   340   14    7   7.5   4.1   32.5  90.4    -0.2   1239  6.3
 18000   -7.7  18.1   345   16    8   7.4   4.0   32.1  89.7    -0.6   1192  6.1
 17500   -6.7  19.9   340   15    8   5.4   2.9   31.6  88.9    -1.0   1145  5.8
 17000   -6.1  21.0   330   15    7   5.6   3.1   30.7  87.3    -1.9   1114  5.7
 16500   -5.0  23.0   325   14    7   8.9   4.9   30.3  86.6    -2.3   1066  5.4
 16000   -3.7  25.3   320   14    7   8.7   4.8   30.2  86.3    -2.4   1013  5.1
 15500   -2.4  27.7   315   12    6   8.7   4.8   30.0  86.0    -2.6    959  4.9
 15000   -1.1  30.0   315   11    6   8.6   4.7   29.8  85.7    -2.8    905  4.6
 14500    0.0  32.0   310    9    5   8.6   4.7   29.6  85.2    -3.1    856  4.3
 14000    1.4  34.5   305    8    4   9.0   4.9   29.5  85.0    -3.2    800  4.1
 13500    2.8  37.0   310   10    5   9.1   5.0   29.3  84.8    -3.3    744  3.8
 13000    4.1  39.4   310   13    7   8.6   4.7   29.2  84.6    -3.5    689  3.5
 12500    5.4  41.7   315   15    8   8.6   4.7   29.0  84.3    -3.7    637  3.2
 12000    6.6  43.9   315   17    9   8.6   4.7   28.9  84.0    -3.9    584  3.0
 11500    7.9  46.2   310   16    8   8.6   4.7   28.7  83.6    -4.1    531  2.7
 11000    9.2  48.6   305   15    8   8.6   4.7   28.5  83.3    -4.3    479  2.4
 10500   10.4  50.7   295   14    7   8.5   4.7   28.3  83.0    -4.5    426  2.2
 10250   11.0  51.8   295   14    7   7.8   4.3   28.2  82.8    -4.7    401  2.0
 10000   11.6  52.9   295   13    7   7.5   4.1   28.0  82.4    -4.9    377  1.9
  9750   12.1  53.8   295   12    6   7.6   4.2   27.8  82.1    -5.1    354  1.8
  9500   12.6  54.7   290   12    6   7.6   4.2   27.7  81.8    -5.3    330  1.7
  9250   13.2  55.8   290   11    6   7.5   4.1   27.5  81.5    -5.5    306  1.6
  9000   13.7  56.7   290   10    5   8.0   4.4   27.4  81.3    -5.7    283  1.4
  8750   14.3  57.7   285    8    4   6.1   3.4   27.2  81.0    -5.9    259  1.3
  8500   14.5  58.1   275    6    3   3.1   1.7   26.8  80.2    -6.3    243  1.2
  8250   14.7  58.5   255    5    2   2.9   1.6   26.2  79.2    -6.9    230  1.2
  8000   15.0  59.0   230    4    2   3.0   1.6   25.7  78.3    -7.4    216  1.1
  7750   15.2  59.4   200    4    2   2.9   1.6   25.2  77.3    -8.0    203  1.0
  7500   15.4  59.7   175    6    3   3.1   1.7   24.6  76.4    -8.5    189  1.0
  7250   15.6  60.1   165    7    4   2.5   1.4   24.1  75.4    -9.1    176  0.9
  7000   15.8  60.4   155   10    5   4.7   2.6   23.6  74.5    -9.6    162  0.8
  6750   16.2  61.2   150    9    5   7.6   4.2   23.4  74.1    -9.9    141  0.7
  6500   16.8  62.2   140    8    4   7.6   4.2   23.2  73.8   -10.1    117  0.6
  6250   17.3  63.1   130    7    4   7.5   4.1   23.0  73.5   -10.3     93  0.5
  6000   17.9  64.2   120    7    4   8.0   4.4   22.9  73.2   -10.5     69  0.4
  5750   18.4  65.1   115    7    3   6.2   3.4   22.7  72.9   -10.7     45  0.2
  5500   18.6  65.5   115    6    3  -3.9  -2.2   22.1  71.9   -11.3     34  0.2
  5250   17.8  64.0   110    6    3 -14.1  -7.7   20.7  69.2   -12.8     48  0.2
  5000   16.6  61.9   110    5    3 -15.0  -8.2   18.8  65.8   -14.8     77  0.4

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

           08/19/2016 at 0900 MDT          |       08/19/2016 at 1200 MDT
                                           |
K index... +27.5  LI... +271.5             | K index... +19.2  LI... +270.8
CAPE... +296.3  CIN... -21.2               | CAPE... +562.2  CIN... -43.0
                                           |
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 -59.2 -74.6  265  28 15   1.6   0.9 | -58.7 -73.7  265  28 14   1.7   0.9
 45000 -57.2 -71.0  255  33 17   0.1   0.1 | -56.9 -70.4  265  34 18  -0.3  -0.2
 40000 -56.6 -69.9  245  27 14   7.2   3.9 | -56.9 -70.4  255  27 14   6.9   3.8
 38000 -52.7 -62.9  255  26 13   6.5   3.6 | -53.0 -63.4  255  25 13   6.5   3.6
 36000 -48.8 -55.8  265  25 13   6.6   3.6 | -49.1 -56.4  255  22 11   6.5   3.6
 34000 -44.1 -47.4  265  24 13   8.4   4.6 | -44.3 -47.7  265  20 10   8.4   4.6
 32000 -39.0 -38.2  270  23 12   8.4   4.6 | -39.3 -38.7  275  19 10   8.4   4.6
 30000 -34.1 -29.4  275  21 11   8.0   4.4 | -33.7 -28.7  290  17  9   8.2   4.5
 29000 -31.1 -24.0  280  19 10   8.0   4.4 | -31.3 -24.3  295  16  8   8.2   4.5
 28000 -28.7 -19.7  285  18  9   7.8   4.3 | -28.8 -19.8  305  15  8   7.9   4.3
 27000 -26.5 -15.7  290  17  9   7.5   4.1 | -26.5 -15.7  310  15  8   7.6   4.2
 26000 -24.2 -11.6  295  17  9   7.5   4.1 | -24.3 -11.7  310  15  8   7.6   4.2
 25000 -22.0  -7.6  300  16  8   7.5   4.1 | -22.0  -7.6  315  15  8   7.7   4.2
 24000 -19.7  -3.5  305  15  8   7.7   4.2 | -19.8  -3.6  320  14  7   7.2   4.0
 23000 -17.4   0.7  315  14  7   7.7   4.2 | -17.6   0.3  330  13  7   7.2   4.0
 22000 -15.0   5.0  325  14  7   7.7   4.2 | -15.5   4.1  340  12  6   7.2   4.0
 21000 -13.1   8.4  330  13  7   6.3   3.5 | -13.4   7.9  355  12  6   7.0   3.8
 20000 -11.2  11.8  340  12  6   6.5   3.6 | -11.3  11.7  005  12  6   7.0   3.8
 19500 -10.3  13.5  345  11  6   6.6   3.6 | -10.3  13.5  010  13  6   7.0   3.8
 19000  -9.4  15.1  345  11  6   6.4   3.5 |  -9.3  15.3  015  13  7   6.8   3.7
 18500  -8.4  16.9  350  11  6   6.3   3.5 |  -8.3  17.1  015  13  7   6.8   3.7
 18000  -7.5  18.5  350  11  6   6.5   3.6 |  -7.2  19.0  015  13  7   6.9   3.8
 17500  -6.5  20.3  350  11  6   7.1   3.9 |  -6.2  20.8  015  13  7   7.4   4.0
 17000  -5.5  22.1  350  12  6   7.0   3.9 |  -5.1  22.8  015  13  7   7.3   4.0
 16500  -4.5  23.9  350  12  6   7.9   4.3 |  -4.0  24.8  015  13  7   8.2   4.5
 16000  -3.3  26.1  350  12  6   8.0   4.4 |  -2.8  27.0  015  13  7   8.3   4.5
 15500  -2.2  28.0  350  13  7   7.6   4.2 |  -1.6  29.1  015  14  7   8.4   4.6
 15000  -1.2  29.8  345  13  7   7.3   4.0 |  -0.4  31.3  020  14  7   8.5   4.7
 14500  -0.2  31.6  340  13  7   7.4   4.1 |   0.9  33.6  020  14  7   8.5   4.7
 14000   1.6  34.9  330  13  7   8.6   4.7 |   2.7  36.9  025  12  6   8.3   4.5
 13500   2.8  37.0  325  13  7   8.5   4.7 |   3.9  39.0  025  11  6   8.2   4.5
 13000   4.0  39.2  315  12  6   8.4   4.6 |   5.1  41.2  020  10  5   8.2   4.5
 12500   5.1  41.2  305  12  6   8.4   4.6 |   6.2  43.2  015   8  4   8.1   4.5
 12000   6.4  43.5  300  12  6   8.4   4.6 |   7.3  45.1  360   7  4   8.0   4.4
 11500   7.6  45.7  295  11  6   8.4   4.6 |   8.4  47.1  345   6  3   8.1   4.4
 11000   8.8  47.8  290  11  6   8.3   4.5 |   9.6  49.3  330   6  3   7.9   4.3
 10500  10.1  50.2  285  11  5   4.8   2.6 |  10.7  51.3  315   6  3   4.9   2.7
 10250  10.3  50.5  285  10  5   5.6   3.1 |  11.0  51.8  310   6  3   5.7   3.1
 10000  11.0  51.8  285  10  5  10.7   5.9 |  11.6  52.9  305   6  3  10.3   5.6
  9750  11.8  53.2  285  10  5   9.8   5.4 |  12.3  54.1  300   6  3   9.4   5.2
  9500  12.5  54.5  285  10  5   8.3   4.6 |  13.0  55.4  290   6  3   8.4   4.6
  9250  13.0  55.4  285   9  5   6.3   3.5 |  13.5  56.3  290   6  3   7.3   4.0
  9000  13.5  56.3  285   9  5   7.5   4.1 |  14.1  57.4  285   6  3   8.2   4.5
  8750  14.1  57.4  285   9  5   8.2   4.5 |  14.7  58.5  280   6  3   8.5   4.7
  8500  14.8  58.6  285   8  4   7.0   3.9 |  15.3  59.5  275   6  3   8.1   4.4
  8250  15.2  59.4  280   8  4   5.9   3.3 |  15.8  60.4  270   6  3   7.6   4.2
  8000  15.7  60.3  275   7  3   5.4   3.0 |  16.3  61.3  265   5  3   8.0   4.4
  7750  16.0  60.8  265   6  3   4.7   2.6 |  16.9  62.4  265   5  3   8.1   4.4
  7500  16.3  61.3  245   5  2   5.2   2.9 |  17.5  63.5  260   5  2   9.4   5.1
  7250  16.7  62.1  225   4  2   5.4   3.0 |  18.3  64.9  260   5  2  10.4   5.7
  7000  17.0  62.6  200   5  2   5.4   3.0 |  19.0  66.2  260   5  2  10.3   5.7
  6750  17.4  63.3  185   5  3   4.8   2.6 |  19.8  67.6  260   5  2  11.0   6.0
  6500  17.7  63.9  180   5  3   3.6   2.0 |  20.6  69.1  260   5  2  11.1   6.1
  6250  17.9  64.2  170   5  3   3.9   2.2 |  21.5  70.7  260   5  2  11.9   6.5
  6000  18.1  64.6  160   5  2   1.6   0.9 |  22.3  72.1  260   5  2   9.2   5.1
  5750  18.2  64.8  150   4  2   5.5   3.0 |  23.0  73.4  260   5  2  11.7   6.4
  5500  19.0  66.2  150   3  2  12.1   6.6 |  24.2  75.6  260   5  2  17.4   9.5
  5250  19.7  67.5  145   3  2   6.9   3.8 |  25.3  77.5  260   5  2  13.3   7.3
  5000     M     M    M   M  M     M     M |     M     M    M   M  M     M     M

           08/19/2016 at 1500 MDT          |       08/19/2016 at 1800 MDT
                                           |
K index... +21.3  LI... +271.1             | K index... +26.8  LI... +271.8
CAPE... +337.4  CIN... -37.3               | CAPE... +220.5  CIN... -36.3
                                           |
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 -59.5 -75.1  265  28 14   1.0   0.6 | -60.1 -76.2  265  32 16   1.2   0.7
 45000 -58.0 -72.4  265  31 16   0.7   0.4 | -58.4 -73.1  265  31 16   0.6   0.3
 40000 -56.5 -69.7  280  22 11   7.2   3.9 | -57.0 -70.6  270  16  8   7.5   4.1
 38000 -52.7 -62.9  270  20 10   6.4   3.5 | -52.9 -63.2  285  14  7   6.8   3.7
 36000 -48.8 -55.8  260  19 10   6.5   3.6 | -48.8 -55.8  300  12  6   6.9   3.8
 34000 -44.1 -47.4  265  15  8   8.3   4.5 | -44.0 -47.2  310  10  5   8.5   4.6
 32000 -39.2 -38.6  285  11  6   8.3   4.5 | -38.9 -38.0  325   8  4   8.5   4.7
 30000 -33.4 -28.1  310  10  5   8.7   4.8 | -33.8 -28.8  330   8  4   8.6   4.7
 29000 -30.8 -23.4  320  11  6   8.7   4.8 | -30.6 -23.1  335   9  4   8.6   4.7
 28000 -28.2 -18.8  330  12  6   8.2   4.5 | -28.0 -18.4  340   9  5   8.1   4.4
 27000 -25.9 -14.6  330  13  7   7.7   4.2 | -25.7 -14.3  335  11  6   7.7   4.2
 26000 -23.6 -10.5  330  14  7   7.7   4.2 | -23.4 -10.1  335  13  7   7.7   4.2
 25000 -21.3  -6.3  335  14  7   7.8   4.3 | -21.1  -6.0  335  15  8   7.7   4.2
 24000 -19.2  -2.6  335  14  7   7.0   3.9 | -18.9  -2.0  335  17  9   7.5   4.1
 23000 -17.1   1.2  330  14  7   7.1   3.9 | -16.7   1.9  335  18  9   7.5   4.1
 22000 -15.0   5.0  330  13  7   7.1   3.9 | -14.5   5.9  330  19 10   7.4   4.1
 21000 -13.1   8.4  335  13  7   6.5   3.6 | -12.5   9.5  330  20 10   6.5   3.5
 20000 -11.2  11.8  335  13  6   6.6   3.6 | -10.6  12.9  325  20 11   6.5   3.6
 19500 -10.3  13.5  335  12  6   6.6   3.6 |  -9.7  14.5  325  21 11   6.4   3.5
 19000  -9.3  15.3  335  12  6   7.8   4.3 |  -8.6  16.5  325  21 11   7.8   4.3
 18500  -8.1  17.4  335  13  7   8.0   4.4 |  -7.5  18.5  325  22 11   8.0   4.4
 18000  -6.9  19.6  335  14  7   8.1   4.4 |  -6.3  20.7  325  22 11   8.0   4.4
 17500  -5.7  21.7  335  14  7   8.3   4.6 |  -5.2  22.6  325  22 11   8.1   4.5
 17000  -4.4  24.1  335  15  7   8.3   4.6 |  -4.0  24.8  330  22 11   8.2   4.5
 16500  -3.2  26.2  335  15  8   8.3   4.5 |  -2.8  27.0  330  21 11   8.5   4.6
 16000  -2.0  28.4  335  15  8   8.3   4.5 |  -1.6  29.1  330  20 11   8.5   4.7
 15500  -0.8  30.6  340  15  8   8.3   4.6 |  -0.4  31.3  335  19 10   8.7   4.8
 15000   0.5  32.9  335  14  7   8.4   4.6 |   0.9  33.6  335  18  9   8.8   4.9
 14500   2.3  36.1  335  13  7   8.4   4.6 |   2.2  36.0  335  17  9   8.9   4.9
 14000   3.5  38.3  335  12  6   8.4   4.6 |   4.2  39.6  335  16  8   9.2   5.0
 13500   4.7  40.5  330  12  6   8.4   4.6 |   5.5  41.9  335  15  8   9.1   5.0
 13000   5.9  42.6  330  11  6   8.3   4.5 |   6.9  44.4  335  14  7   9.0   5.0
 12500   7.1  44.8  330  10  5   8.4   4.6 |   8.2  46.8  335  13  7   9.1   5.0
 12000   8.4  47.1  330   9  5   8.6   4.7 |   9.5  49.1  330  12  6   9.1   5.0
 11500   9.7  49.5  330   8  4   8.4   4.6 |  10.9  51.6  330  11  6   8.9   4.9
 11000  10.9  51.6  330   7  4   7.6   4.2 |  12.1  53.8  325   9  5   7.7   4.3
 10500  12.0  53.6  325   6  3  11.2   6.1 |  13.2  55.8  320   8  4  10.5   5.8
 10250  13.0  55.4  325   6  3  11.9   6.5 |  14.1  57.4  315   8  4  10.9   6.0
 10000  13.6  56.5  325   5  3   7.3   4.0 |  14.7  58.5  310   7  4   7.6   4.2
  9750  14.3  57.7  320   5  3   8.9   4.9 |  15.3  59.5  305   7  3   8.5   4.6
  9500  14.9  58.8  315   5  3   7.0   3.8 |  16.0  60.8  300   6  3   8.3   4.6
  9250  15.3  59.5  310   5  3   7.1   3.9 |  16.6  61.9  290   6  3   8.1   4.5
  9000  15.9  60.6  310   5  3   9.3   5.1 |  17.2  63.0  285   6  3   7.8   4.3
  8750  16.6  61.9  305   5  2   9.3   5.1 |  17.8  64.0  275   5  3   7.8   4.3
  8500  17.3  63.1  305   5  2   9.5   5.2 |  18.4  65.1  270   5  3   8.1   4.4
  8250  17.9  64.2  305   5  2   9.8   5.4 |  19.0  66.2  265   5  3   8.5   4.7
  8000  18.6  65.5  305   5  2   9.7   5.3 |  19.6  67.3  255   5  2   8.0   4.4
  7750  19.3  66.7  300   5  2   9.4   5.2 |  20.2  68.4  255   5  2   7.2   4.0
  7500  20.0  68.0  300   5  2  10.1   5.5 |  20.7  69.3  250   5  2   8.8   4.8
  7250  20.8  69.4  300   5  2  10.9   6.0 |  21.5  70.7  250   5  2  10.8   5.9
  7000  21.6  70.9  300   5  2  10.2   5.6 |  22.3  72.1  250   5  2  10.2   5.6
  6750  22.3  72.1  295   5  2   9.8   5.4 |  23.0  73.4  245   5  2   9.6   5.3
  6500  23.0  73.4  295   5  2  10.8   5.9 |  23.7  74.7  245   5  2  10.4   5.7
  6250  23.9  75.0  295   5  2  11.7   6.4 |  24.5  76.1  245   5  2  11.2   6.1
  6000  24.7  76.5  290   4  2  10.2   5.6 |  25.3  77.5  245   5  2  10.4   5.7
  5750  25.5  77.9  290   4  2  12.1   6.7 |  26.1  79.0  245   5  2   9.8   5.4
  5500  26.6  79.9  290   5  2  16.7   9.2 |  26.8  80.2  245   4  2  10.4   5.7
  5250  27.8  82.0  290   5  2  16.0   8.8 |  27.6  81.7  250   4  2  11.1   6.1
  5000     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) 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 at Walker Field in Grand
Junction, Colorado at

                   North Latitude:  39 deg 07 min 00.001 sec
                   West Longitude: 108 deg 31 min 59.998 sec
                   Elevation: 4839 feet (1475 meters)

and may not be representative of other areas along the Western Slope of
Colorado.  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.