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
000
UXUS97 KGJT 261242
SRGGJT

Soaring Forecast
National Weather Service Grand Junction, Colorado
0642 MDT Tuesday, July 26, 2016

This forecast is for Tuesday, July 26, 2016:

If the trigger temperature of 89.3 F/31.8 C is reached...then
   Thermal Soaring Index....................... Excellent
   Maximum rate of lift........................ 1337 ft/min (6.8 m/s)
   Maximum height of thermals.................. 19654 ft MSL (14815 ft AGL)

Forecast maximum temperature................... 97.0 F/36.6 C
Time of trigger temperature.................... 1130 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................. 11430 ft MSL (6590 ft AGL)
Thermal soaring outlook for Wednesday 07/27.... Excellent

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

Remarks...

Sunrise/Sunset.................... 06:09:54 / 20:31:39 MDT
Total possible sunshine........... 14 hr 21 min 45 sec (861 min 45 sec)
Altitude of sun at 13:20:36 MDT... 70.06 degrees

Upper air data from rawinsonde observation taken on 07/26/2016 at 0600 MDT

Freezing level.................. 16349 ft MSL (11510 ft AGL)
Convective condensation level... 17315 ft MSL (12476 ft AGL)
Lifted condensation level....... 18009 ft MSL (13169 ft AGL)
Lifted index.................... -3.8
K index......................... +22.4

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  -64.7 -84.5   290    9    5   6.1   3.3   85.2 185.4    28.6      M    M
 45000  -57.4 -71.3   255   39   20  -2.4  -1.3   73.1 163.5    23.1      M    M
 40000  -49.1 -56.4   245   50   26   4.6   2.5   62.2 143.9    17.4      M    M
 38000  -45.7 -50.3   255   55   28  -0.8  -0.4   58.5 137.4    15.4      M    M
 36000  -44.6 -48.3   250   47   24   8.5   4.6   51.7 125.1    11.0      M    M
 34000  -39.2 -38.6   240   45   23   8.5   4.7   51.2 124.1    10.8      M    M
 32000  -34.1 -29.4   245   43   22   8.9   4.9   50.2 122.3    10.4      M    M
 30000  -29.3 -20.7   260   35   18   7.3   4.0   47.8 118.1     8.8      M    M
 29000  -26.9 -16.4   255   31   16   8.8   4.9   47.2 116.9     8.4      M    M
 28000  -24.3 -11.7   250   27   14   8.3   4.5   46.9 116.4     8.2      M    M
 27000  -22.7  -8.9   240   23   12   4.9   2.7   45.2 113.4     7.0      M    M
 26000  -20.9  -5.6   250   19   10   7.7   4.2   43.8 110.9     6.0      M    M
 25000  -18.6  -1.5   265   17    9   6.3   3.4   43.1 109.5     5.4      M    M
 24000  -17.8  -0.0   275   13    7   0.7   0.4   40.5 104.9     3.4      M    M
 23000  -16.2   2.8   325    9    5   8.5   4.7   38.9 102.0     2.0      M    M
 22000  -13.8   7.2   340   11    6   8.0   4.4   38.3 100.9     1.6      M    M
 21000  -11.6  11.1   010   16    8   7.8   4.3   37.3  99.2     0.9      M    M
 20000   -9.2  15.4   005   20   10   7.2   3.9   36.8  98.2     0.3      M    M
 19500   -8.2  17.2   005   19   10   8.0   4.4   36.3  97.3    -0.1   1429  7.3
 19000   -7.1  19.2   005   17    9   7.6   4.2   36.0  96.8    -0.5   1382  7.0
 18500   -6.0  21.2   360   15    8   7.7   4.2   35.6  96.1    -0.9   1335  6.8
 18000   -4.9  23.2   360   14    7   8.8   4.8   35.3  95.5    -1.2   1287  6.5
 17500   -3.5  25.7   355   12    6   9.3   5.1   35.2  95.4    -1.3   1231  6.3
 17000   -2.2  28.0   350   10    5   9.4   5.1   35.1  95.2    -1.4   1174  6.0
 16500   -0.1  31.8   340    7    4   9.4   5.1   35.1  95.1    -1.5   1090  5.5
 16000    1.3  34.3   330    6    3   9.4   5.1   35.0  95.1    -1.5   1034  5.3
 15500    2.7  36.9   315    5    3   9.4   5.1   34.9  94.9    -1.7    977  5.0
 15000    4.1  39.4   305    5    3   9.4   5.2   34.9  94.7    -1.7    921  4.7
 14500    5.4  41.7   290    5    3   8.8   4.8   34.8  94.6    -1.9    866  4.4
 14000    6.7  44.1   275    5    3   8.7   4.8   34.6  94.3    -2.0    813  4.1
 13500    8.0  46.4   250    5    3   8.7   4.8   34.4  94.0    -2.2    760  3.9
 13000    9.3  48.7   230    6    3   8.7   4.8   34.3  93.7    -2.4    706  3.6
 12500   10.5  50.9   220    7    4   8.7   4.8   34.1  93.4    -2.6    653  3.3
 12000   11.8  53.2   210    9    5   8.8   4.8   34.0  93.2    -2.8    600  3.0
 11500   13.1  55.6   200    9    5   8.8   4.8   33.8  92.8    -3.0    547  2.8
 11000   14.4  57.9   195    9    5   8.8   4.8   33.6  92.5    -3.2    494  2.5
 10500   15.7  60.3   185    9    5   8.7   4.7   33.4  92.2    -3.4    441  2.2
 10250   16.3  61.3   185   10    5   8.5   4.7   33.3  92.0    -3.5    415  2.1
 10000   16.9  62.4   185   11    6   8.6   4.7   33.2  91.8    -3.6    388  2.0
  9750   17.5  63.5   180   12    6   8.6   4.7   33.2  91.7    -3.7    362  1.8
  9500   18.2  64.8   180   12    6   8.6   4.7   33.1  91.5    -3.8    336  1.7
  9250   18.8  65.8   180   13    7   8.6   4.7   33.0  91.4    -3.9    310  1.6
  9000   19.4  66.9   180   14    7   8.6   4.7   32.9  91.2    -4.0    284  1.4
  8750   20.1  68.2   175   14    7   8.5   4.6   32.8  91.1    -4.1    258  1.3
  8500   20.7  69.3   165   14    7   9.0   4.9   32.7  90.9    -4.3    231  1.2
  8250   21.3  70.3   160   14    7   7.0   3.9   32.6  90.7    -4.4    205  1.0
  8000   21.6  70.9   150   14    7   2.4   1.3   32.2  90.0    -4.8    188  1.0
  7750   21.7  71.1   155   15    8   0.5   0.3   31.6  88.8    -5.4    178  0.9
  7500   21.9  71.4   160   16    8   4.1   2.2   30.9  87.7    -6.0    167  0.8
  7250   22.3  72.1   160   17    9   6.6   3.6   30.7  87.2    -6.3    146  0.7
  7000   22.7  72.9   165   18    9   6.1   3.4   30.4  86.7    -6.7    126  0.6
  6750   23.1  73.6   165   19   10   5.4   3.0   30.1  86.2    -7.0    106  0.5
  6500   23.6  74.5   165   20   10   8.7   4.8   29.8  85.7    -7.3     86  0.4
  6250   24.0  75.2   160   21   11  -3.8  -2.1   29.6  85.2    -7.6     65  0.3
  6000   23.2  73.8   160   22   11  -3.6  -2.0   28.1  82.6    -9.1     82  0.4
  5750   23.7  74.7   160   19   10   9.0   4.9   27.8  82.1    -9.4     61  0.3
  5500   24.1  75.4   155   15    8   6.1   3.4   27.6  81.7    -9.7     39  0.2
  5250   24.6  76.3   150   12    6   5.1   2.8   27.3  81.2   -10.0     17  0.1
  5000   24.7  76.5   135    8    4  -3.7  -2.0   26.7  80.1   -10.7      8  0.0

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

           07/26/2016 at 0900 MDT          |       07/26/2016 at 1200 MDT
                                           |
K index... +28.8  LI... +270.1             | K index... +24.7  LI... +268.5
CAPE... +526.6  CIN... -83.3               | CAPE... +1056.9  CIN... -45.2
                                           |
Height Temperature  Wnd WndSpd  Lapse Rate | Temperature  Wnd WndSpd  Lapse Rate
ft MSL deg C deg F  Dir kt m/s  C/km F/kft | deg C deg F  Dir kt m/s  C/km F/kft
--------------------------------------------------------------------------------
 50000 -62.8 -81.0  300  15  8   3.5   1.9 | -63.5 -82.3  285  15  8   3.5   1.9
 45000 -57.0 -70.6  285  31 16   4.5   2.5 | -56.8 -70.2  280  28 15   6.1   3.3
 40000 -49.9 -57.8  270  48 25   4.8   2.6 | -47.8 -54.0  275  41 21   4.0   2.2
 38000 -47.0 -52.6  260  49 25   4.8   2.6 | -45.4 -49.7  265  43 22   4.0   2.2
 36000 -44.1 -47.4  250  50 26   6.2   3.4 | -43.0 -45.4  260  45 23   5.3   2.9
 34000 -39.2 -38.6  255  44 23   8.3   4.6 | -38.6 -37.5  255  42 22   7.3   4.0
 32000 -34.2 -29.6  255  38 20   9.0   4.9 | -34.2 -29.6  255  39 20   7.5   4.1
 30000 -29.2 -20.6  250  29 15   8.3   4.6 | -30.0 -22.0  250  31 16   7.1   3.9
 29000 -26.8 -16.2  245  25 13   8.3   4.6 | -27.4 -17.3  250  25 13   7.1   3.9
 28000 -24.1 -11.4  240  20 10   4.6   2.5 | -25.3 -13.5  250  21 11   6.8   3.7
 27000 -22.7  -8.9  250  17  9   4.8   2.6 | -23.3  -9.9  255  16  8   6.9   3.8
 26000 -21.2  -6.2  270  14  7   4.8   2.6 | -21.3  -6.3  265  12  6   6.9   3.8
 25000 -19.7  -3.5  290  13  7   6.4   3.5 | -19.3  -2.7  285   8  4   6.8   3.7
 24000 -17.7   0.1  310  10  5   7.0   3.8 | -17.3   0.9  315   7  4   6.8   3.7
 23000 -15.6   3.9  335   9  5   7.0   3.8 | -15.3   4.5  345   8  4   6.8   3.7
 22000 -13.5   7.7  005  11  6   7.4   4.0 | -13.2   8.2  005  10  5   7.3   4.0
 21000 -11.3  11.7  020  11  6   7.4   4.1 | -11.0  12.2  010  10  5   7.4   4.1
 20000  -9.1  15.6  030  13  7   7.4   4.1 |  -8.8  16.2  020  10  5   7.5   4.1
 19500  -8.0  17.6  035  14  7   7.5   4.1 |  -7.7  18.1  025  10  5   7.9   4.3
 19000  -6.9  19.6  035  13  6   7.5   4.1 |  -6.5  20.3  025  10  5   8.8   4.8
 18500  -5.8  21.6  035  11  6   7.4   4.1 |  -5.1  22.8  030  10  5   8.8   4.8
 18000  -4.7  23.5  030  10  5   8.4   4.6 |  -3.9  25.0  030  10  5   8.5   4.7
 17500  -3.5  25.7  015   9  5   8.5   4.7 |  -2.6  27.3  020  10  5   8.5   4.7
 17000  -2.3  27.9  360   9  5   9.1   5.0 |  -1.4  29.5  015  10  5   8.3   4.6
 16500  -0.9  30.4  355   8  4  10.2   5.6 |  -0.2  31.6  010  10  5   8.0   4.4
 16000   0.6  33.1  345   8  4  10.5   5.7 |   1.0  33.8  010  11  6   8.0   4.4
 15500   1.9  35.4  340   7  3   8.0   4.4 |   2.2  36.0  010  11  6   7.8   4.3
 15000   3.2  37.8  330   5  3   8.2   4.5 |   3.3  37.9  010  10  5   7.7   4.2
 14500   4.4  39.9  320   4  2   8.0   4.4 |   4.5  40.1  005  10  5   9.4   5.2
 14000   5.6  42.1  300   4  2   8.0   4.4 |   5.9  42.6  360   8  4   9.9   5.4
 13500   7.3  45.1  285   5  2   9.3   5.1 |   8.0  46.4  345   7  3   9.1   5.0
 13000   8.6  47.5  280   5  3   9.2   5.0 |   9.4  48.9  325   6  3   9.3   5.1
 12500  10.0  50.0  275   6  3   9.4   5.1 |  10.7  51.3  305   6  3   8.7   4.8
 12000  11.3  52.3  270   6  3   9.4   5.2 |  11.9  53.4  295   6  3   8.7   4.8
 11500  12.6  54.7  265   7  3   9.1   5.0 |  13.1  55.6  285   6  3   8.6   4.7
 11000  13.9  57.0  255   7  4   9.4   5.2 |  14.3  57.7  275   7  3   8.9   4.9
 10500  15.0  59.0  250   8  4   4.4   2.4 |  15.3  59.5  265   7  4   4.7   2.6
 10250  15.4  59.7  245   9  4   7.8   4.3 |  15.7  60.3  260   7  4   7.5   4.1
 10000  16.1  61.0  240   9  5  10.6   5.8 |  16.4  61.5  255   7  4   9.5   5.2
  9750  16.9  62.4  235   9  5   9.4   5.2 |  17.0  62.6  255   7  4   8.7   4.8
  9500  17.5  63.5  230  10  5   6.5   3.6 |  17.6  63.7  250   7  4   6.5   3.6
  9250  17.9  64.2  230  10  5   6.6   3.6 |  18.0  64.4  245   7  3   6.5   3.6
  9000  18.6  65.5  225  10  5   9.1   5.0 |  18.5  65.3  240   6  3   8.1   4.4
  8750  19.2  66.6  225  10  5   8.5   4.7 |  19.0  66.2  235   6  3   8.1   4.4
  8500  19.8  67.6  220  11  6   7.7   4.2 |  19.6  67.3  235   6  3   8.8   4.8
  8250  20.4  68.7  220  11  6   7.3   4.0 |  20.2  68.4  235   6  3   9.2   5.0
  8000  20.9  69.6  215  12  6   7.8   4.3 |  20.8  69.4  235   6  3  10.1   5.6
  7750  21.4  70.5  215  12  6   6.9   3.8 |  21.6  70.9  235   6  3  10.4   5.7
  7500  21.8  71.2  210  13  7   5.2   2.9 |  22.3  72.1  235   6  3   9.7   5.3
  7250  22.2  72.0  205  14  7   5.4   3.0 |  23.0  73.4  235   6  3   9.9   5.4
  7000  22.5  72.5  200  15  8   4.3   2.3 |  23.8  74.8  235   6  3   9.3   5.1
  6750  22.7  72.9  195  15  8   2.9   1.6 |  24.5  76.1  235   6  3  10.3   5.7
  6500  22.9  73.2  190  14  7   3.2   1.7 |  25.3  77.5  235   6  3  11.5   6.3
  6250  23.2  73.8  185  12  6   3.2   1.8 |  26.2  79.2  235   5  3  11.5   6.3
  6000  23.4  74.1  180  11  6   2.8   1.5 |  27.0  80.6  235   5  3  10.4   5.7
  5750  23.6  74.5  175   9  5   6.6   3.6 |  27.8  82.0  235   5  3  12.6   6.9
  5500  24.3  75.7  175   9  4  10.5   5.8 |  28.9  84.0  235   5  3  16.1   8.8
  5250  25.0  77.0  175   8  4   7.5   4.1 |  30.0  86.0  235   5  3  13.4   7.3
  5000     M     M    M   M  M     M     M |     M     M    M   M  M     M     M

           07/26/2016 at 1500 MDT          |       07/26/2016 at 1800 MDT
                                           |
K index... +21.0  LI... +270.7             | K index... +23.3  LI... +272.0
CAPE... +555.1  CIN... -43.7               | CAPE... +197.6  CIN... -47.7
                                           |
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 -64.0 -83.2  280  18  9   2.9   1.6 | -64.0 -83.2  285  22 11   2.6   1.4
 45000 -57.5 -71.5  280  32 16   6.7   3.7 | -58.2 -72.8  280  36 19   6.1   3.4
 40000 -47.6 -53.7  285  42 22   4.4   2.4 | -48.8 -55.8  280  40 21   5.3   2.9
 38000 -45.0 -49.0  275  43 22   4.4   2.4 | -45.6 -50.1  280  38 20   5.3   2.9
 36000 -42.4 -44.3  265  45 23   5.8   3.2 | -42.5 -44.5  275  36 19   6.5   3.5
 34000 -38.1 -36.6  260  42 21   7.2   3.9 | -38.0 -36.4  275  33 17   7.5   4.1
 32000 -33.8 -28.8  260  38 20   7.3   4.0 | -33.5 -28.3  275  29 15   7.9   4.4
 30000 -29.1 -20.4  260  32 16   7.9   4.3 | -28.9 -20.0  280  23 12   7.8   4.3
 29000 -26.2 -15.2  265  28 14   7.8   4.3 | -25.9 -14.6  285  20 10   7.9   4.3
 28000 -24.0 -11.2  265  25 13   6.1   3.4 | -23.7 -10.7  285  17  9   6.7   3.7
 27000 -22.2  -8.0  270  22 11   6.2   3.4 | -21.7  -7.1  285  15  8   6.7   3.7
 26000 -20.3  -4.5  275  20 10   6.2   3.4 | -19.7  -3.5  290  12  6   6.7   3.7
 25000 -18.4  -1.1  275  18  9   6.8   3.7 | -17.8  -0.0  290  10  5   6.3   3.4
 24000 -16.4   2.5  285  14  7   7.0   3.9 | -15.9   3.4  295   8  4   6.1   3.4
 23000 -14.3   6.3  295  10  5   7.1   3.9 | -14.1   6.6  295   7  3   6.1   3.4
 22000 -12.2  10.0  315   7  4   7.6   4.2 | -12.2  10.0  300   5  3   7.7   4.2
 21000 -10.0  14.0  345   8  4   7.6   4.2 |  -9.9  14.2  305   5  2   7.9   4.3
 20000  -7.7  18.1  360  10  5   7.7   4.2 |  -7.6  18.3  315   4  2   7.9   4.3
 19500  -6.6  20.1  010  11  6   7.9   4.3 |  -6.4  20.5  320   4  2   7.9   4.3
 19000  -5.4  22.3  010  11  5   8.2   4.5 |  -5.2  22.6  320   4  2   7.9   4.3
 18500  -4.2  24.4  010  10  5   8.3   4.5 |  -4.1  24.6  320   4  2   7.9   4.3
 18000  -3.0  26.6  010  10  5   8.0   4.4 |  -2.9  26.8  320   4  2   7.9   4.3
 17500  -1.8  28.8  010  10  5   8.0   4.4 |  -1.8  28.8  320   4  2   8.0   4.4
 17000  -0.6  30.9  010   9  5   8.2   4.5 |  -0.6  30.9  320   5  2   8.1   4.4
 16500   0.6  33.1  010   9  5   8.6   4.7 |   0.5  32.9  320   5  3   8.3   4.6
 16000   1.9  35.4  010   9  5   8.6   4.7 |   1.8  35.2  325   5  3   8.3   4.5
 15500   3.1  37.6  005   9  5   8.8   4.8 |   3.0  37.4  325   5  3   9.0   4.9
 15000   4.4  39.9  360   9  5   8.8   4.8 |   4.3  39.7  325   5  3   8.9   4.9
 14500   5.6  42.1  355   9  5   8.8   4.8 |   5.6  42.1  330   5  3   9.2   5.0
 14000   6.9  44.4  350   9  4   8.8   4.8 |   7.7  45.9  335   6  3   9.3   5.1
 13500   8.9  48.0  335   8  4   9.0   4.9 |   9.0  48.2  335   6  3   9.1   5.0
 13000  10.2  50.4  330   8  4   9.0   4.9 |  10.3  50.5  335   6  3   9.1   5.0
 12500  11.5  52.7  325   8  4   9.0   4.9 |  11.7  53.1  335   7  4   9.1   5.0
 12000  12.9  55.2  320   7  4   9.0   5.0 |  13.0  55.4  335   7  4   9.2   5.0
 11500  14.2  57.6  310   6  3   8.6   4.7 |  14.4  57.9  335   7  4   9.4   5.1
 11000  15.4  59.7  300   5  3   8.9   4.9 |  15.8  60.4  330   8  4   9.9   5.5
 10500  16.4  61.5  280   5  2   4.8   2.7 |  16.9  62.4  330   8  4   5.6   3.0
 10250  16.9  62.4  275   5  2   8.8   4.8 |  17.4  63.3  325   8  4   9.1   5.0
 10000  17.6  63.7  270   5  3  10.5   5.8 |  18.2  64.8  325   8  4  10.7   5.9
  9750  18.4  65.1  265   5  3  10.1   5.5 |  19.0  66.2  325   8  4  10.5   5.7
  9500  19.0  66.2  260   5  3   7.2   4.0 |  19.7  67.5  320   8  4   7.7   4.2
  9250  19.5  67.1  255   5  3   7.4   4.1 |  20.1  68.2  320   7  4   7.5   4.1
  9000  20.1  68.2  255   5  3   9.8   5.4 |  20.8  69.4  315   7  4   9.7   5.3
  8750  20.7  69.3  255   5  3   9.4   5.1 |  21.4  70.5  315   7  4   9.1   5.0
  8500  21.3  70.3  250   5  3   9.8   5.4 |  22.1  71.8  315   7  3   9.3   5.1
  8250  22.0  71.6  250   5  3  10.0   5.5 |  22.8  73.0  315   7  3   9.2   5.1
  8000  22.7  72.9  250   5  3  10.1   5.6 |  23.4  74.1  310   7  3   9.2   5.0
  7750  23.5  74.3  250   5  3  10.3   5.6 |  24.1  75.4  310   7  3   9.3   5.1
  7500  24.2  75.6  245   5  3  10.3   5.7 |  24.8  76.6  310   6  3   9.7   5.3
  7250  25.0  77.0  245   5  3  10.6   5.8 |  25.5  77.9  310   6  3   9.7   5.3
  7000  25.8  78.4  245   5  3   9.7   5.3 |  26.3  79.3  305   6  3  10.1   5.5
  6750  26.5  79.7  245   5  3   9.8   5.4 |  27.0  80.6  305   6  3  10.6   5.8
  6500  27.3  81.1  245   5  3  10.8   6.0 |  27.8  82.0  305   6  3  10.4   5.7
  6250  28.1  82.6  245   5  3  10.9   6.0 |  28.6  83.5  305   6  3  10.7   5.9
  6000  28.9  84.0  245   5  3  10.3   5.7 |  29.4  84.9  305   6  3   9.8   5.4
  5750  29.7  85.5  245   5  3  13.5   7.4 |  30.1  86.2  305   6  3  10.3   5.6
  5500  30.8  87.4  245   5  3  17.3   9.5 |  30.9  87.6  305   6  3  11.9   6.5
  5250  32.0  89.6  245   5  3  14.4   7.9 |  31.8  89.2  305   6  3  10.6   5.8
  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.