Soaring Guidance
Issued by NWS Grand Junction, CO

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000
UXUS97 KGJT 171240
SRGGJT

Soaring Forecast
National Weather Service Grand Junction, Colorado
0640 MDT Monday, April 17, 2017

This forecast is for Monday, April 17, 2017:

If the trigger temperature of 70.0 F/21.1 C is reached...then
   Thermal Soaring Index....................... Excellent
   Maximum rate of lift........................ 1084 ft/min (5.5 m/s)
   Maximum height of thermals.................. 16732 ft MSL (11893 ft AGL)

Forecast maximum temperature................... 78.0 F/26.0 C
Time of trigger temperature.................... 1115 MDT
Time of overdevelopment........................ 1500 MDT
Middle/high clouds during soaring window....... None
Surface winds during soaring window............ 20 mph or less
Height of the -3 thermal index................. 13817 ft MSL (8977 ft AGL)
Thermal soaring outlook for Tuesday 04/18...... Excellent

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

Remarks...

Sunrise/Sunset.................... 06:34:06 / 19:52:51 MDT
Total possible sunshine........... 13 hr 18 min 44 sec (798 min 44 sec)
Altitude of sun at 13:13:38 MDT... 61.63 degrees

Upper air data from rawinsonde observation taken on 04/17/2017 at 0600 MDT

Freezing level.................. 12115 ft MSL (7276 ft AGL)
Convective condensation level... 20108 ft MSL (15269 ft AGL)
Lifted condensation level....... 19550 ft MSL (14711 ft AGL)
Lifted index.................... +2.0
K index......................... +8.1

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  -62.9 -81.2   280   45   23  -3.9  -2.2   97.3 207.1    40.7      M    M
 45000  -61.1 -78.0   290   40   21   6.3   3.5   74.2 165.6    29.7      M    M
 40000  -67.2 -89.0   285   32   17   5.6   3.1   41.4 106.4    10.4      M    M
 38000  -62.8 -81.0   285   30   16   8.4   4.6   38.9 102.1     9.0      M    M
 36000  -57.6 -71.7   280   29   15   9.9   5.4   38.1 100.5     8.7      M    M
 34000  -51.9 -61.4   275   27   14   9.0   4.9   37.8 100.0     8.7      M    M
 32000  -45.8 -50.4   270   26   13   9.0   4.9   37.1  98.7     8.4      M    M
 30000  -40.7 -41.3   260   27   14   8.6   4.7   36.3  97.3     8.1      M    M
 29000  -38.1 -36.6   255   28   14   8.5   4.7   35.7  96.3     7.7      M    M
 28000  -35.6 -32.1   255   29   15   8.5   4.7   35.3  95.5     7.5      M    M
 27000  -33.0 -27.4   250   30   15   8.7   4.8   34.9  94.8     7.3      M    M
 26000  -30.5 -22.9   255   32   16   6.9   3.8   34.3  93.8     6.9      M    M
 25000  -28.5 -19.3   260   34   17   7.2   4.0   33.2  91.8     6.1      M    M
 24000  -26.8 -16.2   235   32   16   2.2   1.2   31.7  89.1     4.9      M    M
 23000  -24.7 -12.5   235   33   17   5.7   3.1   30.7  87.2     4.1      M    M
 22000  -22.8  -9.0   240   34   17   7.2   4.0   29.5  85.1     3.2      M    M
 21000  -20.6  -5.1   240   35   18   7.3   4.0   28.6  83.5     2.4      M    M
 20000  -18.5  -1.3   240   36   18   7.3   4.0   27.8  82.1     1.8      M    M
 19500  -17.4   0.7   240   35   18   7.2   4.0   27.4  81.3     1.4      M    M
 19000  -16.2   2.8   235   33   17   8.6   4.7   27.1  80.7     1.1      M    M
 18500  -15.0   5.0   235   32   16   7.5   4.1   26.7  80.1     0.9      M    M
 18000  -13.2   8.2   235   31   16   7.8   4.3   26.3  79.4     0.5      M    M
 17500  -12.0  10.4   235   30   15   9.1   5.0   26.0  78.7     0.2      M    M
 17000  -10.6  12.9   235   29   15   7.2   4.0   25.8  78.5     0.2      M    M
 16500   -9.7  14.5   235   29   15   5.2   2.8   25.2  77.3    -0.4   1058  5.4
 16000   -9.0  15.8   235   28   14   5.4   3.0   24.4  76.0    -1.1   1020  5.2
 15500   -8.2  17.2   240   28   14   5.6   3.1   23.7  74.6    -1.9    983  5.0
 15000   -7.4  18.7   240   27   14   6.7   3.7   23.0  73.4    -2.6    945  4.8
 14500   -6.1  21.0   245   27   14   9.0   4.9   22.9  73.2    -2.7    889  4.5
 14000   -4.9  23.2   245   27   14   8.8   4.8   22.7  72.8    -3.0    839  4.3
 13500   -3.6  25.5   245   26   13   8.7   4.8   22.5  72.4    -3.1    784  4.0
 13000   -2.3  27.9   245   24   13   8.7   4.8   22.3  72.1    -3.3    730  3.7
 12500   -0.9  30.4   245   23   12   8.7   4.8   22.2  71.9    -3.4    676  3.4
 12000    0.4  32.7   245   22   11   8.7   4.8   22.0  71.7    -3.6    622  3.2
 11500    1.7  35.1   245   21   11   8.7   4.8   21.8  71.3    -3.8    568  2.9
 11000    3.0  37.4   250   20   10   8.6   4.7   21.7  71.0    -3.9    514  2.6
 10500    4.4  39.9   245   19   10  10.4   5.7   21.6  70.9    -4.0    456  2.3
 10250    5.2  41.4   245   18    9   9.8   5.4   21.7  71.0    -4.0    426  2.2
 10000    5.9  42.6   245   19   10   9.2   5.0   21.6  71.0    -4.0    397  2.0
  9750    6.6  43.9   245   18    9   9.1   5.0   21.6  70.9    -4.1    369  1.9
  9500    7.3  45.1   240   16    8   9.1   5.0   21.6  70.8    -4.1    341  1.7
  9250    7.9  46.2   240   15    7   9.1   5.0   21.5  70.7    -4.2    314  1.6
  9000    8.6  47.5   235   13    7   9.1   5.0   21.5  70.7    -4.2    286  1.5
  8750    9.3  48.7   230   12    6   9.1   5.0   21.4  70.6    -4.3    258  1.3
  8500   10.0  50.0   225   12    6   9.1   5.0   21.4  70.5    -4.3    230  1.2
  8250   10.7  51.3   220   11    6   9.1   5.0   21.3  70.4    -4.4    202  1.0
  8000   11.3  52.3   210   11    6   9.1   5.0   21.3  70.3    -4.5    175  0.9
  7750   12.0  53.6   210   11    6   9.1   5.0   21.2  70.2    -4.5    147  0.7
  7500   12.7  54.9   205   11    6   9.2   5.0   21.2  70.1    -4.6    119  0.6
  7250   13.4  56.1   205   11    6   8.8   4.8   21.1  70.0    -4.7     91  0.5
  7000   14.1  57.4   200   11    6  10.2   5.6   21.1  69.9    -4.7     63  0.3
  6750   14.8  58.6   185   13    6   5.1   2.8   21.0  69.8    -4.8     36  0.2
  6500   14.8  58.6   170   16    8  -0.7  -0.4   20.3  68.6    -5.5     27  0.1
  6250   14.8  58.6   160   20   10   0.7   0.4   19.6  67.2    -6.2     19  0.1
  6000   14.8  58.6   150   24   12  -0.9  -0.5   18.9  65.9    -7.0     12  0.1
  5750   14.5  58.1   145   23   12  -7.6  -4.2   17.8  64.1    -8.0     13  0.1
  5500   13.6  56.5   140   19   10 -16.6  -9.1   16.2  61.1    -9.7     34  0.2
  5250   12.5  54.5   135   16    8  -7.6  -4.2   14.3  57.8   -11.6     60  0.3
  5000   12.4  54.3   125   14    7   1.6   0.9   13.6  56.4   -12.4     54  0.3

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

           04/17/2017 at 0900 MDT          |       04/17/2017 at 1200 MDT
                                           |
K index... +3.7  LI... +2.2                | K index... +6.3  LI... +3.3
CAPE... 0.0  CIN... 0.0                    | CAPE... 0.0  CIN... 0.0
                                           |
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 -62.6 -80.7  300  41 21   0.0   0.0 | -62.8 -81.0  305  41 21   0.7   0.4
 45000 -62.6 -80.7  295  46 24  -0.3  -0.2 | -61.8 -79.2  305  51 26   0.1   0.0
 40000 -63.1 -81.6  280  40 21  -0.4  -0.2 | -61.8 -79.2  290  45 23   0.2   0.1
 38000 -60.6 -77.1  270  36 19   6.7   3.7 | -59.1 -74.4  280  43 22   6.1   3.3
 36000 -56.5 -69.7  255  33 17   6.7   3.7 | -55.5 -67.9  270  42 22   6.1   3.3
 34000 -52.2 -62.0  250  32 17   8.6   4.7 | -51.3 -60.3  265  42 22   8.5   4.7
 32000 -46.3 -51.3  255  33 17   8.6   4.7 | -46.2 -51.2  260  42 22   8.5   4.7
 30000 -41.0 -41.8  260  34 18   9.1   5.0 | -41.0 -41.8  260  42 21   8.9   4.9
 29000 -38.3 -36.9  260  35 18   9.1   5.0 | -38.4 -37.1  260  41 21   8.9   4.9
 28000 -35.6 -32.1  260  36 19   9.1   5.0 | -35.7 -32.3  255  40 21   9.0   4.9
 27000 -33.0 -27.4  260  37 19   7.5   4.1 | -32.5 -26.5  255  40 20   8.2   4.5
 26000 -30.7 -23.3  255  36 19   7.6   4.2 | -30.0 -22.0  255  40 21   8.2   4.5
 25000 -28.4 -19.1  250  36 19   7.6   4.2 | -27.6 -17.7  255  40 21   8.3   4.5
 24000 -26.2 -15.2  245  36 18   6.6   3.6 | -25.3 -13.5  255  40 21   6.4   3.5
 23000 -24.3 -11.7  250  36 18   6.6   3.6 | -23.3  -9.9  250  41 21   6.6   3.6
 22000 -22.3  -8.1  250  35 18   6.7   3.7 | -21.4  -6.5  245  41 21   6.6   3.6
 21000 -20.4  -4.7  245  35 18   6.3   3.4 | -19.5  -3.1  245  41 21   6.1   3.3
 20000 -18.5  -1.3  245  34 17   6.3   3.5 | -17.7   0.1  240  39 20   6.1   3.3
 19500 -17.6   0.3  245  33 17   6.3   3.5 | -16.8   1.8  240  39 20   6.1   3.3
 19000 -16.6   2.1  240  33 17   6.2   3.4 | -15.9   3.4  235  38 20   6.1   3.3
 18500 -15.6   3.9  240  32 17   7.3   4.0 | -15.0   5.0  235  38 19   5.5   3.0
 18000 -14.5   5.9  240  32 16   7.3   4.0 | -14.2   6.4  235  37 19   5.6   3.1
 17500 -13.5   7.7  240  31 16   7.8   4.3 | -13.4   7.9  235  36 19   6.2   3.4
 17000 -12.2  10.0  240  30 16   8.3   4.5 | -12.4   9.7  235  35 18   6.5   3.6
 16500 -10.9  12.4  240  30 15   8.2   4.5 | -11.5  11.3  240  34 17   6.6   3.6
 16000  -9.7  14.5  240  29 15   7.5   4.1 | -10.4  13.3  240  32 17   7.6   4.1
 15500  -8.6  16.5  240  28 14   7.6   4.2 |  -9.2  15.4  240  30 16   7.6   4.2
 15000  -7.1  19.2  240  27 14   7.0   3.8 |  -8.1  17.4  240  28 15   6.8   3.7
 14500  -5.9  21.4  235  26 14   7.1   3.9 |  -7.0  19.4  240  27 14   6.8   3.8
 14000  -4.8  23.4  235  26 13   7.9   4.3 |  -5.9  21.4  240  25 13   7.6   4.2
 13500  -3.7  25.3  235  25 13   7.8   4.3 |  -4.8  23.4  240  25 13   7.8   4.3
 13000  -2.5  27.5  235  25 13   8.7   4.8 |  -3.1  26.4  240  23 12   8.1   4.4
 12500  -1.2  29.8  235  24 12   8.7   4.8 |  -1.9  28.6  240  23 12   8.0   4.4
 12000   0.0  32.0  235  23 12   8.4   4.6 |  -0.7  30.7  240  22 11   8.8   4.9
 11500   1.3  34.3  240  23 12   8.5   4.6 |   0.6  33.1  240  21 11   8.8   4.8
 11000   2.5  36.5  240  22 11   8.5   4.7 |   1.9  35.4  235  20 10   8.9   4.9
 10500   3.8  38.8  240  21 11   9.3   5.1 |   3.2  37.8  235  19 10   7.5   4.1
 10250   4.4  39.9  240  20 10   5.4   2.9 |   3.7  38.7  235  18  9   5.6   3.1
 10000   4.7  40.5  240  19 10   5.4   3.0 |   4.2  39.6  235  17  9   8.5   4.7
  9750   5.3  41.5  240  19 10   9.4   5.2 |   4.9  40.8  235  16  8  10.2   5.6
  9500   6.0  42.8  240  18  9   8.4   4.6 |   5.6  42.1  235  16  8   9.6   5.3
  9250   6.6  43.9  240  17  9   7.6   4.2 |   6.3  43.3  230  15  8   7.9   4.4
  9000   7.1  44.8  240  16  8   6.7   3.7 |   6.8  44.2  230  13  7   7.8   4.3
  8750   7.7  45.9  240  15  8   7.0   3.9 |   7.5  45.5  230  12  6   8.8   4.8
  8500   8.2  46.8  240  14  7   6.6   3.6 |   8.1  46.6  230  11  6   8.7   4.8
  8250   8.6  47.5  240  13  7   5.6   3.1 |   8.8  47.8  230  10  5   9.2   5.1
  8000   9.0  48.2  240  11  6   5.0   2.8 |   9.5  49.1  230   9  5   9.4   5.2
  7750   9.4  48.9  235  10  5   5.3   2.9 |  10.2  50.4  230   9  4   9.3   5.1
  7500   9.8  49.6  230  10  5   4.6   2.5 |  10.9  51.6  235   8  4   9.8   5.4
  7250  10.1  50.2  215   9  5   3.8   2.1 |  11.7  53.1  235   8  4  10.5   5.8
  7000  10.4  50.7  205  10  5   3.8   2.1 |  12.4  54.3  235   8  4  10.0   5.5
  6750  10.7  51.3  195  10  5   3.4   1.9 |  13.2  55.8  235   8  4   9.6   5.3
  6500  10.9  51.6  190  10  5   1.7   0.9 |  13.9  57.0  235   8  4  10.6   5.8
  6250  10.9  51.6  185   9  5   1.1   0.6 |  14.7  58.5  235   8  4  11.7   6.4
  6000  11.0  51.8  175   8  4  -0.1  -0.0 |  15.6  60.1  235   8  4  10.1   5.5
  5750  11.0  51.8  165   6  3   3.3   1.8 |  16.3  61.3  240   7  4  12.1   6.6
  5500  11.5  52.7  160   5  3   8.8   4.8 |  17.4  63.3  240   7  4  16.2   8.9
  5250  12.1  53.8  160   5  2   5.8   3.2 |  18.6  65.5  240   8  4  14.2   7.8
  5000     M     M    M   M  M     M     M |     M     M    M   M  M     M     M

           04/17/2017 at 1500 MDT          |       04/17/2017 at 1800 MDT
                                           |
K index... +17.1  LI... +2.1               | K index... +15.4  LI... +1.9
CAPE... 0.0  CIN... 0.0                    | CAPE... 0.0  CIN... 0.0
                                           |
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 -62.3 -80.1  305  39 20   2.1   1.2 | -63.8 -82.8  305  43 22   2.3   1.3
 45000 -59.4 -74.9  305  51 26  -1.2  -0.7 | -60.5 -76.9  310  61 31  -0.4  -0.2
 40000 -61.3 -78.3  305  57 29  -1.0  -0.5 | -61.2 -78.2  310  66 34  -0.4  -0.2
 38000 -58.5 -73.3  305  56 29   6.8   3.7 | -57.9 -72.2  310  65 34   7.4   4.1
 36000 -54.4 -65.9  310  55 28   6.8   3.7 | -53.4 -64.1  305  63 33   7.4   4.1
 34000 -49.9 -57.8  305  50 26   8.5   4.6 | -48.7 -55.7  305  60 31   8.5   4.7
 32000 -44.8 -48.6  290  42 22   8.4   4.6 | -43.6 -46.5  300  55 28   8.5   4.7
 30000 -39.3 -38.7  275  39 20   8.0   4.4 | -38.1 -36.6  300  49 25   7.7   4.2
 29000 -36.9 -34.4  270  40 21   8.0   4.4 | -35.8 -32.4  300  46 24   7.7   4.2
 28000 -34.5 -30.1  270  41 21   8.0   4.4 | -33.5 -28.3  300  43 22   7.7   4.2
 27000 -32.1 -25.8  265  41 21   7.8   4.3 | -31.2 -24.2  295  40 21   7.4   4.1
 26000 -29.8 -21.6  265  41 21   7.8   4.3 | -29.0 -20.2  295  39 20   7.4   4.1
 25000 -27.5 -17.5  265  41 21   7.8   4.3 | -26.8 -16.2  290  39 20   7.4   4.1
 24000 -25.2 -13.4  260  41 21   6.9   3.8 | -24.6 -12.3  285  38 19   6.6   3.6
 23000 -23.1  -9.6  260  39 20   7.1   3.9 | -22.6  -8.7  285  36 19   6.7   3.7
 22000 -21.1  -6.0  265  38 20   7.0   3.9 | -20.6  -5.1  280  35 18   6.7   3.7
 21000 -19.2  -2.6  260  38 19   5.3   2.9 | -18.8  -1.8  275  34 17   5.9   3.2
 20000 -17.6   0.3  255  38 20   5.4   3.0 | -17.0   1.4  270  33 17   6.0   3.3
 19500 -16.8   1.8  255  38 20   5.4   3.0 | -16.1   3.0  265  32 17   6.0   3.3
 19000 -16.0   3.2  255  39 20   5.3   2.9 | -15.3   4.5  265  32 17   6.0   3.3
 18500 -15.1   4.8  250  39 20   6.9   3.8 | -14.5   5.9  260  32 17   5.0   2.8
 18000 -14.1   6.6  250  39 20   6.7   3.7 | -13.7   7.3  255  33 17   5.2   2.8
 17500 -13.1   8.4  250  40 20   6.4   3.5 | -12.9   8.8  250  35 18   6.8   3.8
 17000 -12.2  10.0  250  39 20   6.2   3.4 | -11.7  10.9  245  34 18   7.9   4.3
 16500 -11.3  11.7  245  39 20   6.3   3.4 | -10.6  12.9  245  34 17   8.1   4.4
 16000 -10.4  13.3  245  37 19   6.7   3.7 |  -9.3  15.3  240  32 17   9.4   5.1
 15500  -9.4  15.1  245  35 18   6.5   3.6 |  -7.9  17.8  240  31 16   9.3   5.1
 15000  -8.3  17.1  240  32 17   7.9   4.3 |  -6.5  20.3  235  29 15   9.1   5.0
 14500  -7.1  19.2  240  30 16   7.8   4.3 |  -4.5  23.9  235  27 14   9.1   5.0
 14000  -5.2  22.6  240  27 14   9.6   5.2 |  -3.1  26.4  235  26 13   9.0   4.9
 13500  -3.7  25.3  240  26 13   9.5   5.2 |  -1.8  28.8  235  24 13   9.0   5.0
 13000  -2.3  27.9  235  24 12   9.5   5.2 |  -0.5  31.1  235  23 12   8.7   4.8
 12500  -0.9  30.4  235  23 12   9.5   5.2 |   0.9  33.6  235  21 11   8.8   4.8
 12000   0.5  32.9  235  21 11   9.3   5.1 |   2.1  35.8  235  20 10   8.1   4.4
 11500   1.9  35.4  235  19 10   9.6   5.3 |   3.3  37.9  235  18  9   8.2   4.5
 11000   3.2  37.8  240  18  9   7.2   4.0 |   4.5  40.1  235  16  8   7.2   4.0
 10500   4.2  39.6  245  15  8  10.3   5.7 |   5.6  42.1  235  14  7   7.8   4.3
 10250   5.2  41.4  245  14  7  11.0   6.0 |   6.2  43.2  235  13  7   9.6   5.3
 10000   5.8  42.4  245  13  7   7.4   4.1 |   6.9  44.4  235  12  6   8.8   4.8
  9750   6.4  43.5  250  12  6   8.4   4.6 |   7.5  45.5  240  11  5   7.7   4.2
  9500   7.0  44.6  255  11  6   8.1   4.4 |   8.1  46.6  245   9  5   8.0   4.4
  9250   7.6  45.7  255  11  5   8.3   4.6 |   8.7  47.7  245   8  4   7.8   4.3
  9000   8.3  46.9  255  10  5   9.7   5.3 |   9.3  48.7  250   8  4   8.8   4.8
  8750   9.0  48.2  260  10  5  10.4   5.7 |  10.0  50.0  250   7  4   9.6   5.2
  8500   9.8  49.6  260  10  5  10.2   5.6 |  10.7  51.3  255   7  4   9.4   5.1
  8250  10.6  51.1  260  10  5  10.6   5.8 |  11.5  52.7  255   7  3  10.5   5.8
  8000  11.3  52.3  260  10  5   9.8   5.4 |  12.3  54.1  260   7  3  10.2   5.6
  7750  12.0  53.6  260  10  5   8.6   4.7 |  13.0  55.4  260   7  3   9.1   5.0
  7500  12.7  54.9  260  10  5   9.7   5.3 |  13.7  56.7  260   6  3   9.7   5.3
  7250  13.5  56.3  260  10  5  11.2   6.1 |  14.4  57.9  260   6  3  10.4   5.7
  7000  14.3  57.7  260  10  5  10.5   5.7 |  15.2  59.4  265   6  3  10.0   5.5
  6750  15.0  59.0  265  10  5   9.4   5.1 |  15.9  60.6  265   6  3   8.8   4.8
  6500  15.8  60.4  265  10  5  10.6   5.8 |  16.6  61.9  265   6  3  10.0   5.5
  6250  16.6  61.9  265  10  5  12.4   6.8 |  17.4  63.3  265   6  3  11.4   6.2
  6000  17.5  63.5  265   9  5  10.0   5.5 |  18.2  64.8  265   6  3  10.8   5.9
  5750  18.2  64.8  265   9  5  10.7   5.9 |  19.0  66.2  265   6  3  10.0   5.5
  5500  19.2  66.6  265   9  5  15.3   8.4 |  19.7  67.5  265   6  3   9.3   5.1
  5250  20.4  68.7  265   9  5  15.3   8.4 |  20.4  68.7  265   6  3   9.5   5.2
  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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