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 8 9 10 11 12 13 14
000
UXUS97 KGJT 271355
SRGGJT

Soaring Forecast
National Weather Service Grand Junction, Colorado
0755 MDT Saturday, August 27, 2016

This forecast is for Saturday, August 27, 2016:

If the trigger temperature of 71.5 F/21.9 C is reached...then
   Thermal Soaring Index....................... Good
   Maximum rate of lift........................ 604 ft/min (3.1 m/s)
   Maximum height of thermals.................. 14610 ft MSL (9771 ft AGL)

Forecast maximum temperature................... 81.0 F/27.7 C
Time of trigger temperature.................... 1100 MDT
Time of overdevelopment........................ None
Middle/high clouds during soaring window....... Broken/overcast thin middle
Surface winds during soaring window............ 20 mph or less
Height of the -3 thermal index................. 11887 ft MSL (7047 ft AGL)
Thermal soaring outlook for Sunday 08/28....... Good

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

Remarks...

Sunrise/Sunset.................... 06:38:47 / 19:52:45 MDT
Total possible sunshine........... 13 hr 13 min 58 sec (793 min 58 sec)
Altitude of sun at 13:15:21 MDT... 60.58 degrees

Upper air data from rawinsonde observation taken on 08/27/2016 at 0600 MDT

Freezing level.................. 13612 ft MSL (8773 ft AGL)
Convective condensation level... 13587 ft MSL (8748 ft AGL)
Lifted condensation level....... 14044 ft MSL (9205 ft AGL)
Lifted index.................... -1.9
K index......................... +22.7

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  -58.6 -73.5   250   38   19  -2.3  -1.3  100.1 212.3    41.9      M    M
 45000  -55.6 -68.1   260   39   20   4.2   2.3   79.3 174.7    32.1      M    M
 40000  -56.6 -69.9   265   39   20   5.3   2.9   54.9 130.8    18.3      M    M
 38000  -57.4 -71.3   265   59   30  -0.6  -0.4   44.9 112.9    12.0      M    M
 36000  -52.9 -63.2   260   38   20   7.5   4.1   42.9 109.2    10.9      M    M
 34000  -47.7 -53.9   250   30   16   9.6   5.2   42.0 107.6    10.6      M    M
 32000  -41.3 -42.3   245   33   17   9.5   5.2   41.8 107.3    10.7      M    M
 30000  -36.3 -33.3   240   29   15   7.7   4.2   40.8 105.5    10.2      M    M
 29000  -33.7 -28.7   245   28   14   8.6   4.7   40.4 104.6    10.0      M    M
 28000  -31.2 -24.2   245   27   14   8.3   4.6   39.8 103.6     9.7      M    M
 27000  -28.7 -19.7   250   26   13   8.3   4.6   39.3 102.8     9.4      M    M
 26000  -26.2 -15.2   265   28   14   8.3   4.5   38.8 101.8     9.1      M    M
 25000  -23.6 -10.5   265   24   12   7.6   4.2   38.4 101.2     8.9      M    M
 24000  -21.6  -6.9   260   19   10   7.6   4.2   37.2  99.0     8.0      M    M
 23000  -19.4  -2.9   255   16    8   6.8   3.7   36.5  97.7     7.4      M    M
 22000  -17.9  -0.2   240   13    7   6.6   3.6   34.9  94.8     6.1      M    M
 21000  -15.7   3.7   255   10    5   8.9   4.9   34.0  93.1     5.4      M    M
 20000  -13.1   8.4   275    7    4   9.0   4.9   33.6  92.5     5.2      M    M
 19500  -12.0  10.4   285    8    4   6.9   3.8   33.2  91.7     4.8      M    M
 19000  -11.1  12.0   285    9    5   5.1   2.8   32.5  90.5     4.3      M    M
 18500  -10.1  13.8   285    8    4   7.3   4.0   32.0  89.6     3.9      M    M
 18000   -9.2  15.4   290    7    4   3.2   1.7   31.3  88.4     3.3      M    M
 17500   -8.7  16.3   295    6    3   3.3   1.8   29.5  85.0     1.7      M    M
 17000   -8.0  17.6   300    5    3   8.2   4.5   28.8  83.8     0.9      M    M
 16500   -6.6  20.1   305    5    2   9.1   5.0   28.7  83.6     0.8      M    M
 16000   -5.3  22.5   310    4    2   9.1   5.0   28.6  83.4     0.7      M    M
 15500   -4.0  24.8   295    2    1   8.7   4.8   28.5  83.2     0.6      M    M
 15000   -2.8  27.0   260    1    1   7.3   4.0   28.1  82.7     0.2      M    M
 14500   -1.8  28.8   300    4    2   7.4   4.0   27.7  81.9    -0.1    787  4.0
 14000   -0.7  30.7   305    7    4   7.4   4.0   27.4  81.2    -0.5    740  3.8
 13500    0.4  32.7   300    9    4   7.4   4.1   26.9  80.5    -0.9    693  3.5
 13000    1.4  34.5   295   10    5   7.9   4.3   26.6  79.8    -1.3    646  3.3
 12500    2.2  36.0   265    9    5   2.2   1.2   25.8  78.5    -2.1    610  3.1
 12000    2.8  37.0   240   11    6   7.3   4.0   25.0  77.0    -2.9    577  2.9
 11500    3.9  39.0   230   11    6   7.8   4.3   24.7  76.4    -3.3    527  2.7
 11000    5.1  41.2   225   11    6   7.8   4.3   24.4  75.9    -3.6    478  2.4
 10500    6.2  43.2   240   11    6   7.7   4.2   24.1  75.3    -3.9    428  2.2
 10250    6.8  44.2   245   11    6   6.9   3.8   23.9  75.0    -4.1    404  2.1
 10000    7.3  45.1   245   11    6   6.5   3.6   23.6  74.5    -4.3    382  1.9
  9750    7.8  46.0   240   11    5   6.4   3.5   23.4  74.0    -4.6    361  1.8
  9500    8.2  46.8   240   10    5   7.4   4.0   23.1  73.6    -4.8    339  1.7
  9250    8.9  48.0   235   10    5   9.0   5.0   23.0  73.4    -5.0    313  1.6
  9000    9.5  49.1   235   10    5   9.3   5.1   23.0  73.4    -5.0    285  1.4
  8750   10.2  50.4   220   10    5   9.2   5.0   22.9  73.3    -5.1    258  1.3
  8500   10.9  51.6   205   10    5   9.3   5.1   22.9  73.2    -5.2    230  1.2
  8250   11.5  52.7   190   11    6   9.1   5.0   22.9  73.1    -5.2    203  1.0
  8000   12.2  54.0   175   13    7   9.7   5.3   22.8  73.1    -5.3    175  0.9
  7750   12.9  55.2   170   14    7   7.4   4.0   22.8  73.0    -5.4    148  0.8
  7500   13.3  55.9   170   16    8   4.5   2.5   22.4  72.4    -5.7    129  0.7
  7250   13.6  56.5   165   17    9   4.2   2.3   22.0  71.7    -6.2    112  0.6
  7000   13.9  57.0   165   19   10   5.6   3.1   21.6  70.9    -6.6     95  0.5
  6750   14.1  57.4   160   19   10  -3.8  -2.1   21.1  70.0    -7.1     81  0.4
  6500   13.4  56.1   160   18    9  -5.1  -2.8   19.8  67.6    -8.5     94  0.5
  6250   13.6  56.5   155   18    9   5.8   3.2   19.2  66.5    -9.2     83  0.4
  6000   14.0  57.2   150   18    9   6.9   3.8   18.9  66.1    -9.4     61  0.3
  5750   14.6  58.3   145   16    8   7.1   3.9   18.7  65.7    -9.7     39  0.2
  5500   15.1  59.2   140   14    7   7.5   4.1   18.5  65.3    -9.9     16  0.1
  5250   15.6  60.1   130   12    6   5.9   3.2   18.3  65.0   -10.1      M    M
  5000   15.7  60.3   120   10    5  -5.5  -3.0   17.7  63.9   -10.8      M    M

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

           08/27/2016 at 0900 MDT          |       08/27/2016 at 1200 MDT
                                           |
K index... +21.9  LI... +273.1             | K index... +21.5  LI... +271.5
CAPE... +3.4  CIN... -22.5                 | CAPE... +171.9  CIN... -27.1
                                           |
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 -59.3 -74.7  250  32 16   1.6   0.9 | -59.1 -74.4  240  33 17   1.7   0.9
 45000 -57.3 -71.1  250  43 22  -0.2  -0.1 | -57.3 -71.1  240  43 22  -0.8  -0.5
 40000 -57.6 -71.7  275  40 21   3.0   1.6 | -58.5 -73.3  265  34 17   3.9   2.1
 38000 -54.2 -65.6  270  42 22   5.7   3.1 | -54.5 -66.1  255  35 18   6.7   3.7
 36000 -50.8 -59.4  265  45 23   5.6   3.1 | -50.5 -58.9  250  38 20   6.7   3.7
 34000 -46.3 -51.3  260  40 20   8.6   4.7 | -45.7 -50.3  245  33 17   8.6   4.7
 32000 -41.1 -42.0  265  29 15   8.6   4.7 | -40.5 -40.9  240  24 13   8.6   4.7
 30000 -35.5 -31.9  270  22 11   8.3   4.5 | -34.9 -30.8  240  16  8   8.2   4.5
 29000 -33.0 -27.4  275  19 10   8.3   4.5 | -32.4 -26.3  240  13  7   8.2   4.5
 28000 -30.5 -22.9  275  17  9   8.2   4.5 | -30.0 -22.0  245  10  5   8.2   4.5
 27000 -28.2 -18.8  270  16  8   7.9   4.3 | -27.6 -17.7  240  10  5   8.0   4.4
 26000 -25.8 -14.4  265  16  8   7.9   4.3 | -25.2 -13.4  235  11  5   8.0   4.4
 25000 -23.5 -10.3  255  15  8   8.0   4.4 | -22.8  -9.0  230  11  6   8.2   4.5
 24000 -21.3  -6.3  250  15  8   7.1   3.9 | -20.7  -5.3  225  13  7   6.7   3.7
 23000 -19.2  -2.6  245  14  7   7.1   3.9 | -18.7  -1.7  225  15  8   6.8   3.7
 22000 -17.1   1.2  245  13  7   7.2   4.0 | -16.7   1.9  230  17  9   6.8   3.7
 21000 -15.0   5.0  245  12  6   6.6   3.6 | -14.8   5.4  225  16  8   6.4   3.5
 20000 -13.0   8.6  245  11  6   6.7   3.7 | -12.9   8.8  225  14  7   6.4   3.5
 19500 -12.0  10.4  245  11  5   6.7   3.7 | -12.0  10.4  225  13  7   6.5   3.5
 19000 -11.0  12.2  245  10  5   6.2   3.4 | -11.0  12.2  225  12  6   6.1   3.4
 18500 -10.1  13.8  245   9  5   6.0   3.3 | -10.1  13.8  230  11  5   6.0   3.3
 18000  -9.2  15.4  250   8  4   6.0   3.3 |  -9.2  15.4  230   9  5   6.0   3.3
 17500  -8.3  17.1  255   7  4   6.0   3.3 |  -8.3  17.1  235   8  4   6.0   3.3
 17000  -7.5  18.5  255   6  3   6.0   3.3 |  -7.4  18.7  240   7  4   6.0   3.3
 16500  -6.5  20.3  260   5  3   7.0   3.8 |  -6.5  20.3  240   6  3   7.1   3.9
 16000  -5.5  22.1  265   5  2   7.3   4.0 |  -5.4  22.3  245   5  3   7.4   4.0
 15500  -4.4  24.1  265   4  2   7.3   4.0 |  -4.3  24.3  255   4  2   7.5   4.1
 15000  -3.4  25.9  265   4  2   7.4   4.1 |  -3.2  26.2  255   4  2   7.7   4.2
 14500  -1.8  28.8  260   4  2   7.3   4.0 |  -1.5  29.3  260   3  2   7.6   4.2
 14000  -0.8  30.6  250   4  2   7.3   4.0 |  -0.4  31.3  255   4  2   7.6   4.1
 13500   0.2  32.4  245   5  2   7.4   4.0 |   0.6  33.1  250   4  2   7.6   4.2
 13000   1.3  34.3  240   5  2   7.5   4.1 |   1.7  35.1  250   4  2   7.6   4.2
 12500   2.3  36.1  235   4  2   7.6   4.2 |   2.8  37.0  250   4  2   7.8   4.3
 12000   3.5  38.3  235   4  2   7.8   4.3 |   3.9  39.0  255   4  2   8.0   4.4
 11500   4.6  40.3  235   5  2   7.8   4.3 |   5.0  41.0  255   5  3   7.9   4.3
 11000   5.7  42.3  230   4  2   7.5   4.1 |   6.2  43.2  250   5  2   7.6   4.2
 10500   6.8  44.2  220   4  2   3.9   2.1 |   7.3  45.1  245   4  2   5.1   2.8
 10250   6.9  44.4  215   4  2   4.3   2.4 |   7.6  45.7  240   4  2   6.2   3.4
 10000   7.6  45.7  210   4  2   9.7   5.3 |   8.3  46.9  235   4  2  10.2   5.6
  9750   8.2  46.8  200   3  2   9.0   4.9 |   9.0  48.2  230   3  2   9.8   5.4
  9500   8.8  47.8  190   3  2   7.9   4.3 |   9.6  49.3  220   3  2   7.7   4.2
  9250   9.3  48.7  185   4  2   6.2   3.4 |  10.1  50.2  215   3  2   5.4   3.0
  9000   9.8  49.6  180   4  2   7.5   4.1 |  10.5  50.9  210   3  1   7.7   4.2
  8750  10.4  50.7  180   5  3   8.2   4.5 |  11.1  52.0  205   3  1   8.5   4.7
  8500  11.0  51.8  175   6  3   7.5   4.1 |  11.8  53.2  195   2  1   8.4   4.6
  8250  11.5  52.7  175   8  4   7.4   4.0 |  12.4  54.3  195   2  1   8.4   4.6
  8000  12.0  53.6  175   9  5   6.6   3.6 |  13.0  55.4  190   2  1   8.9   4.9
  7750  12.4  54.3  170  11  5   5.3   2.9 |  13.6  56.5  195   2  1   9.5   5.2
  7500  12.8  55.0  165  12  6   4.9   2.7 |  14.3  57.7  200   2  1   9.7   5.3
  7250  13.2  55.8  165  12  6   4.6   2.5 |  15.0  59.0  205   2  1   9.9   5.4
  7000  13.5  56.3  165  13  7   4.7   2.6 |  15.7  60.3  210   2  1   9.8   5.4
  6750  13.9  57.0  160  13  7   5.2   2.9 |  16.5  61.7  210   2  1  10.4   5.7
  6500  14.2  57.6  160  11  6   5.4   2.9 |  17.3  63.1  210   2  1  11.1   6.1
  6250  14.6  58.3  160  10  5   5.9   3.3 |  18.1  64.6  210   2  1  11.3   6.2
  6000  15.0  59.0  155   8  4   3.7   2.0 |  18.9  66.0  215   2  1  10.3   5.7
  5750  15.2  59.4  155   6  3   6.1   3.3 |  19.7  67.5  220   2  1  12.2   6.7
  5500  15.9  60.6  150   5  3  11.1   6.1 |  20.8  69.4  220   2  1  15.1   8.3
  5250  16.6  61.9  150   5  3   7.1   3.9 |  21.8  71.2  225   2  1  12.8   7.0
  5000     M     M    M   M  M     M     M |     M     M    M   M  M     M     M

           08/27/2016 at 1500 MDT          |       08/27/2016 at 1800 MDT
                                           |
K index... +19.8  LI... +272.0             | K index... +20.2  LI... +272.8
CAPE... +53.5  CIN... -37.4                | CAPE... +0.8  CIN... -26.0
                                           |
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 -59.0 -74.2  245  36 18   1.7   0.9 | -59.3 -74.7  240  35 18   1.4   0.8
 45000 -57.3 -71.1  240  45 23  -0.9  -0.5 | -57.8 -72.0  235  41 21  -0.5  -0.3
 40000 -58.4 -73.1  240  36 18   4.1   2.2 | -58.4 -73.1  245  38 20   4.4   2.4
 38000 -54.4 -65.9  240  36 18   6.7   3.7 | -54.3 -65.7  235  34 17   6.8   3.7
 36000 -50.4 -58.7  240  35 18   6.7   3.7 | -50.2 -58.4  225  31 16   6.8   3.7
 34000 -45.5 -49.9  235  31 16   8.9   4.9 | -44.5 -48.1  225  26 13   9.1   5.0
 32000 -39.5 -39.1  225  25 13   8.9   4.9 | -39.1 -38.4  235  22 11   9.1   5.0
 30000 -34.4 -29.9  220  20 10   8.6   4.7 | -33.9 -29.0  240  18  9   8.4   4.6
 29000 -31.8 -25.2  220  17  9   8.6   4.7 | -31.4 -24.5  235  16  8   8.4   4.6
 28000 -29.2 -20.6  215  15  8   8.4   4.6 | -28.9 -20.0  235  13  7   8.2   4.5
 27000 -26.9 -16.4  220  15  8   7.6   4.2 | -26.7 -16.1  235  12  6   7.5   4.1
 26000 -24.6 -12.3  225  16  8   7.7   4.2 | -24.4 -11.9  235  11  5   7.6   4.1
 25000 -22.4  -8.3  225  16  8   7.7   4.3 | -22.2  -8.0  235   9  5   7.6   4.2
 24000 -20.2  -4.4  230  16  8   6.9   3.8 | -20.1  -4.2  240   8  4   6.8   3.7
 23000 -18.2  -0.8  225  15  8   6.9   3.8 | -18.1  -0.6  245   6  3   6.8   3.7
 22000 -16.2   2.8  225  14  7   7.0   3.9 | -16.1   3.0  260   4  2   6.9   3.8
 21000 -14.3   6.3  230  12  6   6.1   3.3 | -14.2   6.4  285   3  2   6.4   3.5
 20000 -12.5   9.5  235  10  5   6.1   3.3 | -12.3   9.9  320   3  2   6.5   3.5
 19500 -11.6  11.1  235   9  5   6.1   3.3 | -11.3  11.7  335   4  2   6.5   3.5
 19000 -10.7  12.7  240   8  4   6.4   3.5 | -10.4  13.3  345   4  2   6.5   3.6
 18500  -9.8  14.4  235   6  3   6.5   3.6 |  -9.4  15.1  355   4  2   6.6   3.6
 18000  -8.8  16.2  235   5  3   6.5   3.6 |  -8.5  16.7  005   4  2   6.6   3.6
 17500  -7.9  17.8  240   4  2   5.7   3.1 |  -7.5  18.5  010   4  2   7.0   3.8
 17000  -7.0  19.4  250   3  2   5.7   3.1 |  -6.4  20.5  015   4  2   6.9   3.8
 16500  -6.1  21.0  265   3  1   6.8   3.7 |  -5.4  22.3  020   4  2   7.1   3.9
 16000  -5.1  22.8  275   3  1   7.1   3.9 |  -4.3  24.3  015   4  2   7.2   3.9
 15500  -3.4  25.9  295   2  1   8.4   4.6 |  -2.7  27.1  010   4  2   7.4   4.0
 15000  -2.1  28.2  305   2  1   8.4   4.6 |  -1.6  29.1  015   3  2   7.4   4.0
 14500  -0.8  30.6  320   2  1   8.8   4.8 |  -0.5  31.1  020   3  1   7.9   4.3
 14000   0.5  32.9  315   2  1   8.9   4.9 |   0.7  33.3  015   2  1   8.1   4.5
 13500   1.8  35.2  315   2  1   8.5   4.7 |   1.9  35.4  005   2  1   8.4   4.6
 13000   3.0  37.4  300   2  1   8.1   4.4 |   3.2  37.8  360   1  1   8.8   4.8
 12500   4.2  39.6  290   2  1   8.1   4.5 |   4.5  40.1  360   1  1   8.8   4.8
 12000   5.3  41.5  285   2  1   8.2   4.5 |   5.8  42.4  360   1  0   8.5   4.7
 11500   6.5  43.7  280   3  1   8.2   4.5 |   7.1  44.8  000   0  0   8.4   4.6
 11000   7.7  45.9  280   3  2   7.9   4.3 |   8.3  46.9  195   1  0   7.9   4.3
 10500   8.8  47.8  275   3  2   5.0   2.7 |   9.5  49.1  200   1  1   4.3   2.4
 10250   9.1  48.4  275   4  2   5.6   3.1 |   9.7  49.5  185   1  1   5.5   3.0
 10000   9.8  49.6  275   4  2   9.9   5.4 |  10.5  50.9  180   1  1  11.2   6.1
  9750  10.4  50.7  275   4  2   9.1   5.0 |  11.2  52.2  175   2  1  10.1   5.5
  9500  11.1  52.0  275   5  2   8.0   4.4 |  12.0  53.6  175   2  1   8.8   4.8
  9250  11.6  52.9  270   5  2   6.9   3.8 |  12.5  54.5  180   2  1   6.8   3.7
  9000  12.1  53.8  270   4  2   8.5   4.6 |  13.1  55.6  185   2  1   8.0   4.4
  8750  12.7  54.9  265   4  2   8.9   4.9 |  13.7  56.7  185   2  1   8.8   4.8
  8500  13.4  56.1  265   4  2   9.1   5.0 |  14.3  57.7  185   2  1   7.8   4.3
  8250  14.0  57.2  265   4  2   9.5   5.2 |  14.8  58.6  190   2  1   6.7   3.7
  8000  14.7  58.5  265   4  2   9.5   5.2 |  15.3  59.5  195   2  1   7.1   3.9
  7750  15.4  59.7  265   4  2   9.6   5.3 |  15.7  60.3  200   2  1   7.3   4.0
  7500  16.1  61.0  260   4  2  10.2   5.6 |  16.2  61.2  200   3  1   7.8   4.3
  7250  16.9  62.4  260   4  2  10.7   5.9 |  16.8  62.2  200   3  1   8.3   4.6
  7000  17.6  63.7  260   4  2  10.1   5.5 |  17.4  63.3  205   3  1   8.2   4.5
  6750  18.4  65.1  260   4  2  10.0   5.5 |  17.9  64.2  200   3  1   9.1   5.0
  6500  19.2  66.6  260   4  2  10.8   5.9 |  18.6  65.5  200   3  1  10.2   5.6
  6250  20.0  68.0  260   4  2  11.1   6.1 |  19.4  66.9  205   3  1  10.7   5.9
  6000  20.8  69.4  260   4  2  10.5   5.7 |  20.2  68.4  205   3  2   9.9   5.4
  5750  21.6  70.9  255   4  2  12.4   6.8 |  20.9  69.6  205   3  2   9.3   5.1
  5500  22.6  72.7  260   4  2  14.9   8.2 |  21.6  70.9  205   3  1   9.8   5.4
  5250  23.7  74.7  260   4  2  13.0   7.1 |  22.3  72.1  205   3  1   9.4   5.1
  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.