Soaring Guidance
Issued by NWS Grand Junction, CO

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000
UXUS97 KGJT 171247
SRGGJT

Soaring Forecast
National Weather Service Grand Junction, Colorado
0647 MDT Sunday, September 17, 2017

This forecast is for Sunday, September 17, 2017:

If the trigger temperature of 72.4 F/22.5 C is reached...then
   Thermal Soaring Index....................... Excellent
   Maximum rate of lift........................ 927 ft/min (4.7 m/s)
   Maximum height of thermals.................. 15966 ft MSL (11127 ft AGL)

Forecast maximum temperature................... 78.0 F/26.0 C
Time of trigger temperature.................... 1145 MDT
Time of overdevelopment........................ 1300 MDT
Middle/high clouds during soaring window....... Overcast thin high
Surface winds during soaring window............ 20 mph or less
Height of the -3 thermal index................. 8829 ft MSL (3990 ft AGL)
Thermal soaring outlook for Monday 09/18....... Good

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

Remarks...

Sunrise/Sunset.................... 06:57:32 / 19:20:15 MDT
Total possible sunshine........... 12 hr 22 min 43 sec (742 min 43 sec)
Altitude of sun at 13:08:25 MDT... 52.84 degrees

Upper air data from rawinsonde observation taken on 09/17/2017 at 0600 MDT

Freezing level.................. 13009 ft MSL (8170 ft AGL)
Convective condensation level... 15831 ft MSL (10992 ft AGL)
Lifted condensation level....... 15957 ft MSL (11118 ft AGL)
Lifted index.................... +2.7
K index......................... +20.0

Height  Temperature  Wind  Wind Spd  Lapse Rate  ConvectionT  Thermal  Lift Rate
ft MSL  deg C deg F   Dir   kt  m/s  C/km F/kft  deg C deg F   Index    fpm  m/s
--------------------------------------------------------------------------------
 50000  -59.6 -75.3   245   39   20  -4.7  -2.6   98.3 209.0    41.8      M    M
 45000  -57.5 -71.5   245   48   25  -5.0  -2.8   77.4 171.3    31.9      M    M
 40000  -59.9 -75.8   230   42   22   2.4   1.3   50.6 123.1    16.5      M    M
 38000  -56.3 -69.3   225   34   18   7.6   4.2   47.2 116.9    14.7      M    M
 36000  -51.3 -60.3   230   35   18   9.0   4.9   46.0 114.8    14.2      M    M
 34000  -46.5 -51.7   230   37   19   4.3   2.3   43.4 110.1    12.8      M    M
 32000  -42.2 -44.0   225   41   21   9.3   5.1   41.2 106.1    11.5      M    M
 30000  -37.6 -35.7   225   42   22   4.6   2.5   39.6 103.3    10.6      M    M
 29000  -35.4 -31.7   225   40   21   9.4   5.2   38.6 101.6     9.9      M    M
 28000  -32.6 -26.7   225   38   20   8.9   4.9   38.4 101.2     9.9      M    M
 27000  -29.9 -21.8   230   37   19   8.9   4.9   38.1 100.6     9.8      M    M
 26000  -27.5 -17.5   230   35   18   7.5   4.1   37.6  99.6     9.5      M    M
 25000  -24.9 -12.8   230   33   17   7.3   4.0   37.1  98.7     9.2      M    M
 24000  -22.6  -8.7   230   31   16   8.0   4.4   36.3  97.4     8.7      M    M
 23000  -20.0  -4.0   225   29   15   8.3   4.5   35.9  96.7     8.5      M    M
 22000  -17.5   0.5   225   27   14   8.2   4.5   35.4  95.8     8.2      M    M
 21000  -15.0   5.0   225   30   15   7.4   4.1   34.9  94.8     7.8      M    M
 20000  -13.6   7.5   225   33   17   4.0   2.2   33.1  91.5     6.4      M    M
 19500  -13.0   8.6   225   33   17   3.6   2.0   32.1  89.7     5.5      M    M
 19000  -11.7  10.9   230   33   17   7.1   3.9   31.1  88.0     4.8      M    M
 18500  -10.6  12.9   235   35   18   7.8   4.3   30.6  87.1     4.4      M    M
 18000  -10.0  14.0   235   37   19  -0.8  -0.4   29.6  85.3     3.5      M    M
 17500  -10.6  12.9   230   40   21   3.5   1.9   27.5  81.6     1.5      M    M
 17000   -9.9  14.2   225   42   22   1.4   0.8   26.8  80.3     0.7      M    M
 16500   -9.0  15.8   225   41   21   9.5   5.2   26.2  79.2     0.1      M    M
 16000   -7.7  18.1   225   39   20   8.9   4.9   26.1  79.0    -0.0   1023  5.2
 15500   -6.4  20.5   230   36   19   8.9   4.9   25.9  78.7    -0.2    968  4.9
 15000   -5.0  23.0   235   33   17   8.9   4.9   25.8  78.4    -0.3    913  4.6
 14500   -3.7  25.3   240   30   16   8.9   4.9   25.6  78.1    -0.4    858  4.4
 14000   -2.4  27.7   245   28   14   8.9   4.9   25.5  77.9    -0.5    804  4.1
 13500   -1.1  30.0   245   24   12   8.6   4.7   25.3  77.6    -0.7    750  3.8
 13000    0.1  32.2   240   21   11   8.7   4.7   25.1  77.2    -1.0    700  3.6
 12500    1.4  34.5   240   17    9   8.8   4.8   25.0  77.0    -1.2    647  3.3
 12000    2.7  36.9   235   14    7   8.8   4.8   24.8  76.7    -1.3    592  3.0
 11500    4.0  39.2   230   14    7   8.8   4.8   24.7  76.4    -1.5    538  2.7
 11000    5.3  41.5   225   13    7   8.8   4.8   24.5  76.1    -1.7    484  2.5
 10500    6.6  43.9   220   13    7   8.8   4.8   24.4  75.8    -1.8    430  2.2
 10250    7.3  45.1   215   13    7   8.5   4.7   24.3  75.7    -1.9    403  2.0
 10000    7.9  46.2   210   13    7   8.3   4.6   24.2  75.5    -2.0    377  1.9
  9750    8.5  47.3   205   13    7   8.4   4.6   24.0  75.3    -2.1    350  1.8
  9500    9.2  48.6   200   13    7   8.1   4.5   23.9  75.1    -2.2    324  1.6
  9250    9.8  49.6   195   14    7   9.1   5.0   23.8  74.9    -2.3    298  1.5
  9000   10.4  50.7   190   14    7   4.4   2.4   23.7  74.7    -2.5    272  1.4
  8750   10.5  50.9   180   14    7  -0.1  -0.0   23.0  73.4    -3.1    263  1.3
  8500   10.5  50.9   170   14    7   1.1   0.6   22.3  72.2    -3.8    253  1.3
  8250   10.6  51.1   160   15    8   0.8   0.4   21.6  70.9    -4.5    244  1.2
  8000   10.7  51.3   150   16    8   1.0   0.5   20.9  69.7    -5.1    235  1.2
  7750   10.7  51.3   145   15    8   0.6   0.3   20.3  68.5    -5.8    225  1.1
  7500   10.9  51.6   145   15    7   5.4   3.0   19.7  67.4    -6.4    213  1.1
  7250   11.5  52.7   140   14    7   9.2   5.1   19.6  67.2    -6.5    187  1.0
  7000   12.1  53.8   135   13    7   8.2   4.5   19.5  67.0    -6.6    161  0.8
  6750   12.8  55.0   130   12    6   8.4   4.6   19.4  66.8    -6.8    135  0.7
  6500   13.4  56.1   120   11    6   8.6   4.7   19.3  66.7    -6.9    109  0.6
  6250   14.0  57.2   115   10    5   7.7   4.2   19.2  66.5    -7.0     83  0.4
  6000   14.5  58.1   105   10    5   4.9   2.7   18.9  66.0    -7.3     61  0.3
  5750   14.7  58.5   100    9    5   0.6   0.3   18.4  65.1    -7.8     46  0.2
  5500   14.4  57.9   105    9    4 -10.6  -5.8   17.3  63.2    -8.9     49  0.3
  5250   13.1  55.6   110    8    4 -22.2 -12.2   15.3  59.5   -11.0     82  0.4
  5000   11.4  52.5   115    7    4 -17.9  -9.8   12.9  55.2   -13.4    125  0.6

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

           09/17/2017 at 0900 MDT          |       09/17/2017 at 1200 MDT
                                           |
K index... +26.4  LI... -0.1               | K index... +26.9  LI... +0.2
CAPE... +5.9  CIN... -9.9                  | CAPE... +4.5  CIN... -9.5
                                           |
Height Temperature  Wnd WndSpd  Lapse Rate | Temperature  Wnd WndSpd  Lapse Rate
ft MSL deg C deg F  Dir kt m/s  C/km F/kft | deg C deg F  Dir kt m/s  C/km F/kft
--------------------------------------------------------------------------------
 50000 -58.3 -72.9  255  33 17   1.0   0.6 | -58.7 -73.7  250  31 16   0.5   0.3
 45000 -57.1 -70.8  255  39 20  -0.7  -0.4 | -57.6 -71.7  260  33 17   2.2   1.2
 40000 -58.2 -72.8  245  45 23  -1.6  -0.9 | -54.2 -65.6  260  40 21   2.5   1.4
 38000 -54.9 -66.8  245  43 22   6.3   3.5 | -52.2 -62.0  250  44 23   3.4   1.9
 36000 -51.2 -60.2  240  42 21   6.3   3.5 | -50.2 -58.4  240  49 25   3.4   1.8
 34000 -46.6 -51.9  240  40 20   7.1   3.9 | -46.7 -52.1  240  49 25   7.6   4.2
 32000 -42.3 -44.1  235  38 19   7.1   3.9 | -42.2 -44.0  240  44 23   7.6   4.2
 30000 -37.8 -36.0  235  36 19   7.8   4.3 | -37.7 -35.9  235  41 21   7.2   4.0
 29000 -35.4 -31.7  230  36 19   7.8   4.3 | -35.6 -32.1  235  40 21   7.2   4.0
 28000 -33.1 -27.6  230  36 18   7.7   4.2 | -33.4 -28.1  230  39 20   7.3   4.0
 27000 -30.6 -23.1  230  35 18   8.8   4.8 | -30.4 -22.7  230  38 20   8.5   4.6
 26000 -27.9 -18.2  230  35 18   8.8   4.8 | -27.9 -18.2  230  37 19   8.5   4.6
 25000 -25.3 -13.5  230  35 18   8.7   4.8 | -25.4 -13.7  230  36 19   8.5   4.6
 24000 -22.8  -9.0  230  35 18   7.4   4.0 | -23.0  -9.4  230  35 18   7.7   4.2
 23000 -20.6  -5.1  230  34 17   7.4   4.0 | -20.7  -5.3  230  34 18   7.7   4.2
 22000 -18.4  -1.1  230  33 17   7.4   4.0 | -18.4  -1.1  230  34 17   7.8   4.3
 21000 -16.5   2.3  230  33 17   5.9   3.2 | -16.4   2.5  225  34 18   5.9   3.2
 20000 -14.8   5.4  230  34 18   5.8   3.2 | -14.7   5.5  225  36 18   5.9   3.2
 19500 -13.9   7.0  230  35 18   5.9   3.2 | -13.8   7.2  225  36 19   5.9   3.2
 19000 -13.0   8.6  230  35 18   6.0   3.3 | -12.9   8.8  225  37 19   6.1   3.3
 18500 -12.1  10.2  230  36 18   6.3   3.4 | -12.0  10.4  225  37 19   6.5   3.6
 18000 -11.2  11.8  230  36 18   6.2   3.4 | -11.1  12.0  220  36 19   6.6   3.6
 17500 -10.2  13.6  225  36 18   6.9   3.8 | -10.1  13.8  220  36 18   6.7   3.7
 17000  -9.3  15.3  225  34 18   7.1   3.9 |  -9.2  15.4  220  34 18   6.8   3.7
 16500  -8.3  17.1  225  33 17   7.3   4.0 |  -8.3  17.1  215  33 17   6.7   3.7
 16000  -7.2  19.0  225  31 16   7.6   4.2 |  -7.4  18.7  215  31 16   6.6   3.6
 15500  -5.6  21.9  225  29 15   8.3   4.6 |  -6.5  20.3  215  29 15   6.9   3.8
 15000  -4.4  24.1  225  27 14   8.5   4.7 |  -5.4  22.3  215  27 14   8.2   4.5
 14500  -3.2  26.2  225  25 13   8.6   4.7 |  -4.2  24.4  215  25 13   8.1   4.5
 14000  -1.9  28.6  225  24 12   8.6   4.7 |  -3.0  26.6  220  24 12   8.7   4.8
 13500  -0.6  30.9  220  24 12   8.8   4.8 |  -1.7  28.9  220  24 12   8.6   4.7
 13000   0.8  33.4  220  23 12   9.6   5.3 |   0.3  32.5  220  23 12   9.2   5.1
 12500   2.2  36.0  220  22 12   9.4   5.2 |   1.7  35.1  225  23 12   9.2   5.0
 12000   3.5  38.3  220  22 11   8.1   4.5 |   3.0  37.4  225  23 12   8.8   4.8
 11500   4.7  40.5  220  22 11   8.2   4.5 |   4.4  39.9  225  22 11   8.8   4.8
 11000   6.0  42.8  220  21 11   8.2   4.5 |   5.7  42.3  225  21 11   8.6   4.7
 10500   7.3  45.1  220  21 11   5.6   3.1 |   7.0  44.6  225  19 10   5.5   3.0
 10250   7.5  45.5  220  20 10   5.0   2.8 |   7.3  45.1  225  18  9   5.9   3.3
 10000   8.1  46.6  220  20 10   9.3   5.1 |   8.0  46.4  225  18  9  10.4   5.7
  9750   8.8  47.8  220  19 10   9.6   5.3 |   8.7  47.7  225  17  9   9.5   5.2
  9500   9.5  49.1  220  19 10   8.7   4.8 |   9.4  48.9  225  16  8   8.8   4.8
  9250  10.1  50.2  215  18  9   5.9   3.2 |  10.0  50.0  225  15  8   6.4   3.5
  9000  10.5  50.9  215  17  9   5.5   3.0 |  10.4  50.7  225  14  7   6.6   3.6
  8750  10.9  51.6  210  16  8   6.7   3.7 |  11.0  51.8  225  12  6   7.5   4.1
  8500  11.4  52.5  205  15  8   5.4   3.0 |  11.5  52.7  225  11  6   6.7   3.7
  8250  11.7  53.1  200  15  8   3.8   2.1 |  12.0  53.6  225  10  5   5.7   3.1
  8000  12.0  53.6  195  14  7   3.3   1.8 |  12.4  54.3  220   9  5   5.7   3.2
  7750  12.2  54.0  185  13  7   3.5   1.9 |  12.8  55.0  220   8  4   5.5   3.0
  7500  12.5  54.5  175  12  6   2.4   1.3 |  13.2  55.8  215   7  3   6.9   3.8
  7250  12.6  54.7  170  11  6   1.2   0.7 |  13.8  56.8  215   5  3   8.1   4.4
  7000  12.7  54.9  165  11  5   2.0   1.1 |  14.4  57.9  210   4  2   7.9   4.3
  6750  12.9  55.2  155  10  5   1.4   0.8 |  15.0  59.0  215   3  2   9.0   4.9
  6500  12.9  55.2  150   8  4  -1.7  -0.9 |  15.7  60.3  220   3  1  10.4   5.7
  6250  12.7  54.9  140   7  4  -2.0  -1.1 |  16.5  61.7  225   3  1  11.5   6.3
  6000  12.5  54.5  130   6  3  -5.0  -2.8 |  17.4  63.3  230   2  1   9.3   5.1
  5750  12.1  53.8  100   5  3  -1.2  -0.7 |  18.0  64.4  240   2  1  10.1   5.5
  5500  12.4  54.3  095   5  2   6.5   3.6 |  18.9  66.0  240   2  1  13.4   7.4
  5250  12.7  54.9  090   5  2   0.4   0.2 |  19.8  67.6  240   2  1  10.9   6.0
  5000     M     M    M   M  M     M     M |     M     M    M   M  M     M     M

           09/17/2017 at 1500 MDT          |       09/17/2017 at 1800 MDT
                                           |
K index... +27.1  LI... -0.7               | K index... +24.5  LI... -1.2
CAPE... +30.2  CIN... -22.3                | CAPE... +62.9  CIN... -45.5
                                           |
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  255  36 19   0.2   0.1 | -59.3 -74.7  250  37 19   1.3   0.7
 45000 -58.4 -73.1  255  41 21   3.5   1.9 | -56.9 -70.4  255  46 24   3.4   1.8
 40000 -52.9 -63.2  255  45 23   3.0   1.6 | -51.6 -60.9  250  53 27   2.9   1.6
 38000 -51.7 -61.1  250  48 25   2.0   1.1 | -50.7 -59.3  245  52 27   1.5   0.8
 36000 -50.5 -58.9  245  52 27   2.0   1.1 | -49.8 -57.6  245  52 27   1.5   0.8
 34000 -47.2 -53.0  245  52 27   8.1   4.4 | -47.3 -53.1  245  50 26   6.3   3.5
 32000 -42.4 -44.3  245  48 25   8.1   4.4 | -43.5 -46.3  240  48 25   6.4   3.5
 30000 -37.7 -35.9  245  45 23   7.7   4.2 | -38.8 -37.8  245  45 23   9.3   5.1
 29000 -35.4 -31.7  245  44 22   7.7   4.2 | -36.1 -33.0  245  43 22   9.3   5.1
 28000 -33.0 -27.4  240  43 22   7.7   4.2 | -33.3 -27.9  255  41 21   9.3   5.1
 27000 -30.1 -22.2  240  41 21   7.9   4.4 | -30.0 -22.0  255  40 21   8.3   4.6
 26000 -27.7 -17.9  240  41 21   7.9   4.4 | -27.6 -17.7  260  41 21   8.4   4.6
 25000 -25.4 -13.7  235  40 21   7.9   4.4 | -25.1 -13.2  260  41 21   8.3   4.6
 24000 -23.0  -9.4  235  40 20   7.6   4.2 | -22.9  -9.2  260  41 21   6.2   3.4
 23000 -20.8  -5.4  235  39 20   7.6   4.2 | -21.1  -6.0  260  39 20   6.2   3.4
 22000 -18.5  -1.3  235  38 20   7.7   4.2 | -19.3  -2.7  255  37 19   6.2   3.4
 21000 -16.6   2.1  235  38 19   5.5   3.0 | -17.4   0.7  255  36 18   6.0   3.3
 20000 -15.0   5.0  235  38 20   5.5   3.0 | -15.6   3.9  250  35 18   6.0   3.3
 19500 -14.2   6.4  235  38 20   5.5   3.0 | -14.7   5.5  250  34 18   6.1   3.3
 19000 -13.4   7.9  235  38 20   5.6   3.1 | -13.7   7.3  250  34 17   6.8   3.8
 18500 -12.6   9.3  230  37 19   5.9   3.2 | -12.6   9.3  245  34 18   8.0   4.4
 18000 -11.8  10.8  230  35 18   5.8   3.2 | -11.4  11.5  245  35 18   8.1   4.5
 17500 -10.8  12.6  230  34 17   8.3   4.5 | -10.2  13.6  240  36 18   7.1   3.9
 17000  -9.7  14.5  225  31 16   8.3   4.5 |  -9.2  15.4  240  36 19   7.3   4.0
 16500  -8.5  16.7  225  29 15   8.9   4.9 |  -8.2  17.2  235  36 19   7.9   4.3
 16000  -7.2  19.0  220  27 14   9.3   5.1 |  -7.1  19.2  235  34 17   8.3   4.5
 15500  -5.9  21.4  220  25 13   9.1   5.0 |  -5.9  21.4  230  32 16   8.5   4.7
 15000  -4.7  23.5  215  24 12   7.5   4.1 |  -4.7  23.5  230  30 15   9.2   5.0
 14500  -3.6  25.5  215  23 12   7.5   4.1 |  -3.3  26.1  230  28 14   9.3   5.1
 14000  -2.4  27.7  215  22 11   8.7   4.8 |  -2.1  28.2  230  26 13   8.3   4.5
 13500  -1.1  30.0  215  21 11   8.6   4.7 |  -0.2  31.6  230  24 12   8.5   4.7
 13000   0.9  33.6  220  19 10   8.8   4.8 |   1.1  34.0  235  22 12   8.8   4.9
 12500   2.2  36.0  220  18  9   8.7   4.8 |   2.4  36.3  235  21 11   8.8   4.8
 12000   3.4  38.1  225  17  9   8.4   4.6 |   3.7  38.7  240  20 10   8.4   4.6
 11500   4.7  40.5  225  16  8   8.3   4.6 |   4.9  40.8  245  19 10   8.4   4.6
 11000   5.9  42.6  230  14  7   7.7   4.2 |   6.1  43.0  245  18  9   7.4   4.1
 10500   7.1  44.8  235  13  7   4.7   2.6 |   7.2  45.0  250  16  8   5.7   3.1
 10250   7.3  45.1  240  13  6   5.6   3.1 |   7.6  45.7  255  16  8   6.1   3.3
 10000   8.0  46.4  240  12  6  10.3   5.6 |   8.2  46.8  260  15  8   8.9   4.9
  9750   8.7  47.7  245  11  6   9.2   5.1 |   8.8  47.8  260  15  8   8.2   4.5
  9500   9.4  48.9  245  11  5   8.8   4.8 |   9.4  48.9  265  14  7   8.1   4.5
  9250  10.0  50.0  250  10  5   7.3   4.0 |  10.0  50.0  270  14  7   7.7   4.2
  9000  10.5  50.9  255   9  5   7.7   4.2 |  10.6  51.1  270  13  7   8.2   4.5
  8750  11.1  52.0  260   9  4   8.2   4.5 |  11.2  52.2  275  12  6   8.3   4.6
  8500  11.7  53.1  265   8  4   8.2   4.5 |  11.8  53.2  280  12  6   8.7   4.8
  8250  12.3  54.1  270   8  4   8.3   4.6 |  12.5  54.5  285  11  6   9.8   5.4
  8000  13.0  55.4  270   8  4   8.8   4.8 |  13.2  55.8  285  11  6   8.9   4.9
  7750  13.6  56.5  275   8  4   9.3   5.1 |  13.8  56.8  285  11  6   7.6   4.2
  7500  14.3  57.7  275   8  4   9.0   4.9 |  14.4  57.9  290  10  5   8.8   4.8
  7250  15.0  59.0  275   8  4   8.8   4.8 |  15.1  59.2  290  10  5   9.8   5.4
  7000  15.6  60.1  280   8  4   8.9   4.9 |  15.8  60.4  290  10  5   9.4   5.2
  6750  16.3  61.3  280   8  4   9.4   5.1 |  16.5  61.7  290   9  5   9.4   5.1
  6500  17.0  62.6  280   8  4  10.2   5.6 |  17.2  63.0  290   9  5   9.8   5.4
  6250  17.8  64.0  280   8  4  10.8   5.9 |  18.0  64.4  290   8  4  10.0   5.5
  6000  18.6  65.5  280   8  4  10.1   5.6 |  18.7  65.7  290   8  4   9.9   5.4
  5750  19.3  66.7  280   8  4   8.5   4.7 |  19.4  66.9  290   7  4   8.3   4.6
  5500  19.9  67.8  280   8  4   7.6   4.2 |  19.9  67.8  290   7  4   6.8   3.7
  5250  20.5  68.9  275   8  4   8.2   4.5 |  20.4  68.7  295   7  4   7.6   4.2
  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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