Soaring Guidance
Issued by NWS Grand Junction, CO

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000
UXUS97 KGJT 201235
SRGGJT

Soaring Forecast
National Weather Service Grand Junction, Colorado
0635 MDT Sunday, August 20, 2017

This forecast is for Sunday, August 20, 2017:

If the trigger temperature of 86.5 F/30.3 C is reached...then
   Thermal Soaring Index....................... Excellent
   Maximum rate of lift........................ 1445 ft/min (7.3 m/s)
   Maximum height of thermals.................. 19601 ft MSL (14762 ft AGL)

Forecast maximum temperature................... 93.0 F/34.3 C
Time of trigger temperature.................... 1115 MDT
Time of overdevelopment........................ None
Middle/high clouds during soaring window....... None
Surface winds during soaring window............ 20 mph or less
Height of the -3 thermal index................. 10095 ft MSL (5255 ft AGL)
Thermal soaring outlook for Monday 08/21....... Good

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

Remarks...

Sunrise/Sunset.................... 06:32:12 / 20:03:10 MDT
Total possible sunshine........... 13 hr 30 min 58 sec (810 min 58 sec)
Altitude of sun at 13:17:19 MDT... 63.06 degrees

Upper air data from rawinsonde observation taken on 08/20/2017 at 0600 MDT

Freezing level.................. 15580 ft MSL (10741 ft AGL)
Convective condensation level... 17302 ft MSL (12463 ft AGL)
Lifted condensation level....... 18038 ft MSL (13199 ft AGL)
Lifted index.................... -2.3
K index......................... +21.5

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  -64.1 -83.4   265   27   14   6.6   3.6   88.5 191.3    31.6      M    M
 45000  -58.7 -73.7   255   42   22   3.5   1.9   72.0 161.6    23.7      M    M
 40000  -54.7 -66.5   245   46   24   6.2   3.4   55.5 131.9    14.4      M    M
 38000  -50.2 -58.4   240   46   24   6.1   3.4   53.5 128.3    13.4      M    M
 36000  -46.5 -51.7   240   44   23   6.5   3.6   50.3 122.5    11.5      M    M
 34000  -42.8 -45.0   250   37   19   4.8   2.6   47.3 117.2     9.7      M    M
 32000  -37.4 -35.3   255   27   14   9.8   5.3   45.7 114.3     8.7      M    M
 30000  -32.0 -25.6   260   25   13   8.2   4.5   45.2 113.3     8.5      M    M
 29000  -29.6 -21.3   265   25   13   8.2   4.5   44.6 112.2     8.2      M    M
 28000  -27.1 -16.8   260   23   12   8.2   4.5   43.9 111.0     7.8      M    M
 27000  -24.7 -12.5   255   21   11   6.7   3.7   43.3 109.9     7.4      M    M
 26000  -23.6 -10.5   245   20   10  -3.1  -1.7   41.0 105.7     5.5      M    M
 25000  -22.3  -8.1   235   19   10   7.7   4.2   39.1 102.3     4.0      M    M
 24000  -20.2  -4.4   255   17    9   9.1   5.0   38.1 100.6     3.2      M    M
 23000  -17.6   0.3   255   17    9   7.7   4.2   37.8 100.0     3.0      M    M
 22000  -15.7   3.7   260   18    9   6.3   3.4   36.5  97.7     1.9      M    M
 21000  -13.7   7.3   260   19   10   7.6   4.1   35.4  95.8     1.0      M    M
 20000  -11.4  11.5   265   20   10   7.6   4.2   34.7  94.4     0.3      M    M
 19500  -10.3  13.5   260   20   10   7.6   4.2   34.3  93.7    -0.0   1445  7.3
 19000   -9.2  15.4   260   20   10   8.0   4.4   33.9  93.1    -0.3   1397  7.1
 18500   -8.0  17.6   260   19   10   7.2   3.9   33.6  92.5    -0.6   1347  6.8
 18000   -7.2  19.0   260   18    9   6.4   3.5   33.0  91.4    -1.3   1307  6.6
 17500   -5.2  22.6   260   16    8   9.5   5.2   32.8  91.0    -1.5   1226  6.2
 17000   -3.8  25.2   255   16    8   9.6   5.3   32.8  91.0    -1.5   1169  5.9
 16500   -2.4  27.7   255   15    8   9.6   5.3   32.8  91.0    -1.5   1111  5.6
 16000   -1.0  30.2   255   14    7   9.6   5.3   32.8  91.0    -1.6   1053  5.4
 15500    0.5  32.9   255   14    7   9.6   5.3   32.7  90.9    -1.6    996  5.1
 15000    1.9  35.4   255   13    7   9.6   5.3   32.7  90.8    -1.7    938  4.8
 14500    3.3  37.9   255   13    7   9.6   5.3   32.7  90.8    -1.7    880  4.5
 14000    4.8  40.6   255   13    7   9.6   5.3   32.6  90.8    -1.7    823  4.2
 13500    6.2  43.2   265   12    6   8.9   4.9   32.6  90.6    -1.8    766  3.9
 13000    7.5  45.5   280   11    6   8.8   4.8   32.4  90.3    -2.0    712  3.6
 12500    8.8  47.8   290   11    5   8.8   4.8   32.3  90.1    -2.2    659  3.3
 12000   10.1  50.2   305   11    6   8.8   4.8   32.2  89.9    -2.3    605  3.1
 11500   11.4  52.5   295    9    4   8.8   4.9   32.0  89.6    -2.5    551  2.8
 11000   12.7  54.9   285    7    3   8.8   4.9   31.8  89.3    -2.7    498  2.5
 10500   14.0  57.2   265    5    3   8.8   4.8   31.7  89.1    -2.8    444  2.3
 10250   14.6  58.3   260    5    2   8.6   4.7   31.6  88.9    -2.9    417  2.1
 10000   15.2  59.4   255    4    2   8.6   4.7   31.5  88.7    -3.0    391  2.0
  9750   15.9  60.6   255    4    2   8.6   4.7   31.4  88.6    -3.1    364  1.9
  9500   16.5  61.7   250    3    2   8.6   4.7   31.3  88.4    -3.2    338  1.7
  9250   17.1  62.8   245    3    1   8.6   4.7   31.3  88.3    -3.3    311  1.6
  9000   17.8  64.0   235    2    1   8.7   4.8   31.2  88.1    -3.4    285  1.4
  8750   18.4  65.1   220    1    1   8.2   4.5   31.1  88.0    -3.5    258  1.3
  8500   18.9  66.0   125    1    0   5.9   3.2   30.9  87.6    -3.7    235  1.2
  8250   19.3  66.7   090    2    1   4.7   2.6   30.5  86.9    -4.1    217  1.1
  8000   19.7  67.5   080    3    1   5.0   2.8   30.2  86.3    -4.5    199  1.0
  7750   20.0  68.0   090    3    2   5.0   2.8   29.8  85.6    -4.9    181  0.9
  7500   20.4  68.7   095    3    2   4.8   2.6   29.4  84.9    -5.3    163  0.8
  7250   20.7  69.3   105    4    2   5.8   3.2   29.0  84.3    -5.7    145  0.7
  7000   21.1  70.0   110    4    2   2.0   1.1   28.7  83.6    -6.0    127  0.6
  6750   20.9  69.6   115    5    3  -4.6  -2.5   27.8  82.0    -6.9    124  0.6
  6500   20.7  69.3   120    7    3   1.8   1.0   26.8  80.3    -7.9    123  0.6
  6250   21.1  70.0   125    8    4   7.2   3.9   26.6  79.8    -8.2    103  0.5
  6000   21.6  70.9   125   10    5   6.2   3.4   26.3  79.3    -8.5     82  0.4
  5750   22.0  71.6   125    9    5   4.8   2.6   26.0  78.8    -8.8     61  0.3
  5500   22.5  72.5   120    8    4  11.5   6.3   25.7  78.3    -9.1     40  0.2
  5250   22.9  73.2   115    6    3 -13.9  -7.6   25.5  77.8    -9.4     19  0.1
  5000   19.8  67.6   110    5    2 -65.2 -35.8   21.5  70.8   -13.3    107  0.5

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

           08/20/2017 at 0900 MDT          |       08/20/2017 at 1200 MDT
                                           |
K index... +22.2  LI... -0.3               | K index... +22.9  LI... -0.2
CAPE... +22.3  CIN... -37.6                | CAPE... +17.3  CIN... -28.8
                                           |
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 -62.4 -80.3  255  32 17   1.8   1.0 | -62.9 -81.2  250  36 19   2.3   1.2
 45000 -59.1 -74.4  255  42 22   2.9   1.6 | -59.0 -74.2  250  43 22   3.0   1.7
 40000 -54.4 -65.9  250  42 22   6.2   3.4 | -54.1 -65.4  245  42 21   6.0   3.3
 38000 -50.7 -59.3  250  38 19   6.1   3.4 | -50.5 -58.9  245  37 19   6.0   3.3
 36000 -47.0 -52.6  250  34 17   6.1   3.3 | -46.9 -52.4  240  32 16   5.9   3.3
 34000 -42.7 -44.9  250  31 16   7.6   4.2 | -42.6 -44.7  240  28 15   7.5   4.1
 32000 -38.1 -36.6  250  28 14   7.6   4.2 | -38.1 -36.6  245  26 13   7.5   4.1
 30000 -32.5 -26.5  250  24 13   8.5   4.7 | -32.3 -26.1  245  23 12   8.9   4.9
 29000 -30.0 -22.0  250  23 12   8.5   4.7 | -29.7 -21.5  250  22 11   8.9   4.9
 28000 -27.5 -17.5  250  22 11   7.2   4.0 | -27.1 -16.8  250  21 11   7.4   4.1
 27000 -25.4 -13.7  250  20 10   6.8   3.8 | -25.0 -13.0  250  20 10   7.1   3.9
 26000 -23.4 -10.1  250  19 10   6.9   3.8 | -22.8  -9.0  245  19 10   7.1   3.9
 25000 -21.4  -6.5  250  17  9   6.8   3.7 | -20.7  -5.3  240  18  9   6.9   3.8
 24000 -19.5  -3.1  255  16  8   6.4   3.5 | -18.9  -2.0  245  16  8   6.1   3.4
 23000 -17.6   0.3  255  15  8   6.4   3.5 | -17.1   1.2  250  14  7   6.2   3.4
 22000 -15.7   3.7  255  14  7   6.8   3.8 | -15.3   4.5  260  12  6   6.7   3.7
 21000 -13.5   7.7  260  14  7   7.7   4.2 | -13.1   8.4  260  11  6   7.4   4.1
 20000 -11.2  11.8  265  13  7   7.7   4.2 | -10.9  12.4  265  11  6   7.4   4.1
 19500 -10.1  13.8  265  13  7   7.7   4.2 |  -9.8  14.4  265  11  6   7.4   4.1
 19000  -8.9  16.0  265  13  7   7.8   4.3 |  -8.6  16.5  265  10  5   8.2   4.5
 18500  -7.8  18.0  270  12  6   7.8   4.3 |  -7.4  18.7  265   9  5   8.2   4.5
 18000  -6.6  20.1  270  12  6   8.1   4.4 |  -6.2  20.8  265   9  5   8.1   4.4
 17500  -5.4  22.3  270  12  6   8.4   4.6 |  -5.1  22.8  265   9  4   8.1   4.4
 17000  -4.2  24.4  265  12  6   8.4   4.6 |  -3.9  25.0  265   8  4   8.1   4.4
 16500  -2.9  26.8  265  12  6   8.8   4.8 |  -2.7  27.1  265   8  4   8.6   4.7
 16000  -1.6  29.1  265  12  6   8.8   4.8 |  -1.5  29.3  265   8  4   8.5   4.7
 15500  -0.3  31.5  265  12  6   9.2   5.0 |  -0.2  31.6  265   8  4   9.0   4.9
 15000   1.0  33.8  265  11  6   9.3   5.1 |   1.8  35.2  270   8  4   9.0   5.0
 14500   3.1  37.6  265  11  6   9.0   5.0 |   3.1  37.6  275   8  4   9.4   5.2
 14000   4.4  39.9  265  11  6   9.0   5.0 |   4.5  40.1  280   8  4   9.4   5.2
 13500   5.7  42.3  265  10  5   9.1   5.0 |   5.9  42.6  280   8  4   9.2   5.0
 13000   7.1  44.8  265  10  5   9.1   5.0 |   7.2  45.0  285   8  4   9.1   5.0
 12500   8.4  47.1  265   9  5   8.8   4.8 |   8.6  47.5  285   8  4   9.2   5.1
 12000   9.7  49.5  265   8  4   8.6   4.7 |   9.9  49.8  285   8  4   9.3   5.1
 11500  11.0  51.8  265   8  4   8.5   4.7 |  11.3  52.3  285   7  4   8.9   4.9
 11000  12.3  54.1  260   7  3   8.3   4.5 |  12.6  54.7  285   7  4   8.3   4.6
 10500  13.5  56.3  255   5  3   5.5   3.0 |  13.9  57.0  285   7  4   5.9   3.2
 10250  13.8  56.8  255   5  2   6.4   3.5 |  14.2  57.6  285   7  3   7.0   3.8
 10000  14.6  58.3  250   4  2  10.7   5.9 |  14.9  58.8  285   6  3  10.7   5.9
  9750  15.4  59.7  245   4  2   9.9   5.5 |  15.7  60.3  285   6  3  10.5   5.8
  9500  16.1  61.0  240   3  1   8.9   4.9 |  16.4  61.5  285   5  3   7.6   4.2
  9250  16.7  62.1  235   3  1   7.5   4.1 |  16.9  62.4  285   5  2   6.3   3.5
  9000  17.3  63.1  230   2  1   7.9   4.3 |  17.5  63.5  285   4  2   9.0   4.9
  8750  17.9  64.2  215   2  1   8.1   4.4 |  18.2  64.8  285   3  2   8.6   4.7
  8500  18.5  65.3  205   2  1   6.8   3.7 |  18.8  65.8  285   2  1   8.8   4.8
  8250  18.9  66.0  185   2  1   5.8   3.2 |  19.5  67.1  280   2  1   8.8   4.8
  8000  19.3  66.7  170   2  1   5.1   2.8 |  20.2  68.4  275   2  1   8.8   4.8
  7750  19.6  67.3  160   3  1   3.9   2.1 |  20.8  69.4  275   1  1   8.9   4.9
  7500  19.8  67.6  150   3  2   2.6   1.4 |  21.5  70.7  270   1  1   9.1   5.0
  7250  19.9  67.8  145   4  2   1.7   0.9 |  22.2  72.0  265   1  1   9.4   5.1
  7000  20.1  68.2  140   5  2   1.8   1.0 |  22.9  73.2  255   1  1   9.0   4.9
  6750  20.2  68.4  135   5  3   0.7   0.4 |  23.5  74.3  255   1  1   9.8   5.4
  6500  20.2  68.4  130   5  3  -0.4  -0.2 |  24.3  75.7  255   1  1  11.2   6.1
  6250  20.1  68.2  125   5  2  -0.1  -0.1 |  25.2  77.4  250   1  1  11.7   6.4
  6000  20.1  68.2  120   5  2  -1.5  -0.8 |  26.0  78.8  250   1  1  10.1   5.5
  5750  20.0  68.0  110   4  2   4.6   2.5 |  26.8  80.2  250   1  1  12.3   6.7
  5500  20.8  69.4  110   4  2  11.9   6.5 |  27.9  82.2  250   1  1  16.3   9.0
  5250  21.5  70.7  110   4  2   6.2   3.4 |  29.0  84.2  255   1  1  13.1   7.2
  5000     M     M    M   M  M     M     M |     M     M    M   M  M     M     M

           08/20/2017 at 1500 MDT          |       08/20/2017 at 1800 MDT
                                           |
K index... +14.5  LI... -0.0               | K index... +12.6  LI... +0.4
CAPE... +6.0  CIN... -49.0                 | CAPE... +1.8  CIN... -10.9
                                           |
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 -63.4 -82.1  250  39 20   2.2   1.2 | -62.9 -81.2  255  41 21   1.8   1.0
 45000 -59.4 -74.9  245  45 23   3.4   1.9 | -59.4 -74.9  245  47 24   3.5   1.9
 40000 -54.0 -65.2  235  44 23   5.9   3.2 | -53.8 -64.8  230  45 23   6.0   3.3
 38000 -50.4 -58.7  230  40 21   5.9   3.2 | -50.2 -58.4  225  45 23   6.1   3.3
 36000 -46.8 -52.2  225  36 18   5.8   3.2 | -46.5 -51.7  215  45 23   6.0   3.3
 34000 -42.3 -44.1  230  31 16   8.0   4.4 | -41.8 -43.2  220  39 20   8.2   4.5
 32000 -37.5 -35.5  230  27 14   7.9   4.3 | -36.3 -33.3  220  32 16   8.6   4.7
 30000 -31.9 -25.4  240  22 12   8.4   4.6 | -31.5 -24.7  230  25 13   7.9   4.3
 29000 -29.4 -20.9  240  21 11   8.4   4.6 | -29.2 -20.6  235  21 11   7.9   4.3
 28000 -26.9 -16.4  245  19 10   7.9   4.4 | -26.8 -16.2  240  18  9   7.8   4.3
 27000 -24.6 -12.3  250  19 10   7.9   4.3 | -24.5 -12.1  245  17  9   7.8   4.3
 26000 -22.2  -8.0  250  18  9   7.9   4.4 | -22.1  -7.8  250  15  8   7.8   4.3
 25000 -19.9  -3.8  255  18  9   7.5   4.1 | -19.8  -3.6  250  13  7   7.3   4.0
 24000 -18.0  -0.4  255  16  8   6.1   3.3 | -18.1  -0.6  245  12  6   5.5   3.0
 23000 -16.2   2.8  255  13  7   6.1   3.3 | -16.5   2.3  235  11  6   5.6   3.1
 22000 -14.5   5.9  255  11  5   6.5   3.6 | -14.9   5.2  225  11  6   6.5   3.6
 21000 -12.3   9.9  270  10  5   7.1   3.9 | -12.7   9.1  235  11  6   7.7   4.2
 20000 -10.2  13.6  280  11  5   7.1   3.9 | -10.4  13.3  245  12  6   7.7   4.2
 19500  -9.2  15.4  285  11  6   7.0   3.8 |  -9.3  15.3  250  13  7   7.6   4.2
 19000  -8.0  17.6  290  11  5   8.7   4.8 |  -8.1  17.4  255  13  7   8.6   4.7
 18500  -6.7  19.9  290  10  5   8.6   4.7 |  -6.8  19.8  255  12  6   8.5   4.7
 18000  -5.4  22.3  295  10  5   8.5   4.7 |  -5.6  21.9  260  12  6   8.9   4.9
 17500  -4.1  24.6  300   9  5   8.5   4.7 |  -4.2  24.4  260  10  5   9.3   5.1
 17000  -2.8  27.0  300   8  4   8.5   4.7 |  -2.7  27.1  260   9  5   9.4   5.2
 16500  -1.6  29.1  305   8  4   8.6   4.7 |  -1.4  29.5  265   8  4   8.9   4.9
 16000  -0.3  31.5  305   7  4   8.6   4.7 |  -0.0  32.0  275   7  3   8.9   4.9
 15500   1.0  33.8  305   7  4   8.5   4.6 |   1.3  34.3  280   6  3   8.8   4.8
 15000   2.8  37.0  305   7  3   8.4   4.6 |   3.3  37.9  300   5  3   8.8   4.8
 14500   4.1  39.4  305   6  3   9.1   5.0 |   4.7  40.5  310   5  2   8.8   4.8
 14000   5.5  41.9  305   6  3   9.1   5.0 |   6.0  42.8  320   5  3   8.8   4.8
 13500   6.8  44.2  300   6  3   8.9   4.9 |   7.3  45.1  325   5  3   8.8   4.8
 13000   8.1  46.6  295   5  3   8.8   4.8 |   8.6  47.5  330   6  3   8.8   4.8
 12500   9.4  48.9  290   5  3   8.8   4.8 |   9.9  49.8  335   6  3   8.8   4.8
 12000  10.6  51.1  290   5  3   8.8   4.8 |  11.2  52.2  335   7  3   8.8   4.8
 11500  11.9  53.4  285   5  2   8.8   4.8 |  12.5  54.5  335   7  4   8.7   4.8
 11000  13.2  55.8  275   5  2   8.6   4.7 |  13.8  56.8  335   7  4   8.4   4.6
 10500  14.5  58.1  270   5  3   5.3   2.9 |  15.1  59.2  335   8  4   5.7   3.1
 10250  14.8  58.6  270   5  3   6.3   3.5 |  15.4  59.7  335   8  4   6.4   3.5
 10000  15.5  59.9  265   5  3  11.3   6.2 |  16.1  61.0  335   8  4  10.5   5.7
  9750  16.3  61.3  260   5  3  10.7   5.8 |  16.8  62.2  335   8  4   9.8   5.4
  9500  17.0  62.6  260   5  3   8.3   4.5 |  17.5  63.5  335   8  4   8.4   4.6
  9250  17.5  63.5  260   5  3   7.8   4.3 |  18.0  64.4  335   8  4   7.5   4.1
  9000  18.2  64.8  255   6  3  10.5   5.8 |  18.6  65.5  335   8  4   8.9   4.9
  8750  19.0  66.2  255   6  3   9.9   5.4 |  19.2  66.6  335   8  4   8.3   4.6
  8500  19.7  67.5  255   6  3  10.6   5.8 |  19.8  67.6  335   8  4   9.7   5.3
  8250  20.5  68.9  250   6  3  10.8   5.9 |  20.6  69.1  335   8  4  10.9   6.0
  8000  21.3  70.3  250   6  3   9.7   5.3 |  21.3  70.3  335   8  4   9.6   5.3
  7750  22.0  71.6  250   6  3   9.2   5.1 |  22.0  71.6  335   8  4   9.0   5.0
  7500  22.7  72.9  250   6  3   9.8   5.4 |  22.7  72.9  335   8  4   9.7   5.3
  7250  23.5  74.3  250   6  3  10.1   5.5 |  23.5  74.3  335   8  4  10.1   5.6
  7000  24.2  75.6  245   6  3   9.9   5.4 |  24.2  75.6  335   8  4   9.6   5.3
  6750  25.0  77.0  245   6  3  10.4   5.7 |  24.9  76.8  335   8  4   9.5   5.2
  6500  25.8  78.4  245   6  3  11.2   6.1 |  25.7  78.3  330   7  4  10.5   5.7
  6250  26.6  79.9  245   6  3  12.1   6.7 |  26.5  79.7  330   7  4  10.8   5.9
  6000  27.5  81.5  245   6  3   9.3   5.1 |  27.3  81.1  330   7  4  10.6   5.8
  5750  28.2  82.8  245   6  3  12.0   6.6 |  28.1  82.6  330   7  4  10.4   5.7
  5500  29.3  84.7  245   6  3  17.8   9.8 |  28.8  83.8  335   7  4  10.2   5.6
  5250  30.5  86.9  245   6  3  13.3   7.3 |  29.6  85.3  335   7  4  10.3   5.6
  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



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