Soaring Guidance
Issued by NWS Grand Junction, CO

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000
UXUS97 KGJT 261248
SRGGJT

Soaring Forecast
National Weather Service Grand Junction, Colorado
0648 MDT Wednesday, April 26, 2017

This forecast is for Wednesday, April 26, 2017:

If the trigger temperature of 49.5 F/9.7 C is reached...then
   Thermal Soaring Index....................... Good
   Maximum rate of lift........................ 400 ft/min (2.0 m/s)
   Maximum height of thermals.................. 14694 ft MSL (9855 ft AGL)

Forecast maximum temperature................... 60.0 F/16.0 C
Time of trigger temperature.................... 1015 MDT
Time of overdevelopment........................ 1500 MDT
Middle/high clouds during soaring window....... Broken/overcast opaque middle
Surface winds during soaring window............ 20 mph or less
Height of the -3 thermal index................. 12910 ft MSL (8071 ft AGL)
Thermal soaring outlook for Thursday 04/27..... Fair

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

Remarks...

Sunrise/Sunset.................... 06:21:51 / 20:01:40 MDT
Total possible sunshine........... 13 hr 39 min 49 sec (819 min 49 sec)
Altitude of sun at 13:11:55 MDT... 64.64 degrees

Upper air data from rawinsonde observation taken on 04/26/2017 at 0600 MDT

Freezing level.................. 7965 ft MSL (3126 ft AGL)
Convective condensation level... 10133 ft MSL (5294 ft AGL)
Lifted condensation level....... 12096 ft MSL (7257 ft AGL)
Lifted index.................... +0.5
K index......................... +14.9

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  -57.3 -71.1   295   41   21  -8.6  -4.7  107.0 224.6    51.9      M    M
 45000  -56.3 -69.3   315   37   19   8.6   4.7   83.7 182.7    41.4      M    M
 40000  -54.4 -65.9   320   58   30   2.0   1.1   63.4 146.1    31.1      M    M
 38000  -54.7 -66.5   320   72   37  -1.1  -0.6   54.1 129.4    25.7      M    M
 36000  -54.4 -65.9   325   89   46   2.8   1.5   44.8 112.6    20.1      M    M
 34000  -51.6 -60.9   330  100   52   6.7   3.7   40.6 105.0    17.7      M    M
 32000  -47.4 -53.3   325   84   43   6.9   3.8   37.9 100.3    16.2      M    M
 30000  -44.0 -47.2   320   68   35   4.2   2.3   34.8  94.7    14.3      M    M
 29000  -42.6 -44.7   320   61   31   4.6   2.5   32.6  90.7    12.9      M    M
 28000  -41.3 -42.3   315   53   27   4.6   2.5   30.6  87.1    11.5      M    M
 27000  -40.2 -40.4   315   46   24   2.6   1.4   28.2  82.8     9.8      M    M
 26000  -38.3 -36.9   310   39   20   8.1   4.5   26.9  80.5     8.9      M    M
 25000  -35.9 -32.6   305   32   17   8.0   4.4   26.3  79.4     8.5      M    M
 24000  -33.5 -28.3   310   35   18   8.0   4.4   25.6  78.2     8.1      M    M
 23000  -31.0 -23.8   315   37   19   8.7   4.8   25.1  77.3     7.7      M    M
 22000  -28.8 -19.8   310   38   19   6.3   3.5   24.3  75.7     7.1      M    M
 21000  -27.1 -16.8   305   36   18   6.8   3.7   22.8  73.0     5.9      M    M
 20000  -25.4 -13.7   295   34   18   5.7   3.1   21.2  70.1     4.7      M    M
 19500  -24.0 -11.2   295   30   16   7.2   4.0   20.2  68.4     4.0      M    M
 19000  -23.0  -9.4   300   27   14   7.2   4.0   19.7  67.5     3.6      M    M
 18500  -21.9  -7.4   300   25   13   7.6   4.1   19.3  66.8     3.2      M    M
 18000  -20.6  -5.1   300   23   12   8.6   4.7   19.1  66.3     3.0      M    M
 17500  -19.4  -2.9   300   23   12   8.3   4.6   18.9  65.9     2.9      M    M
 17000  -18.2  -0.8   300   22   11   7.5   4.1   18.5  65.3     2.5      M    M
 16500  -17.1   1.2   300   22   11   7.6   4.2   18.1  64.6     2.2      M    M
 16000  -16.0   3.2   300   21   11   7.9   4.3   17.8  64.0     1.9      M    M
 15500  -15.2   4.6   300   19   10  -1.2  -0.7   17.0  62.7     1.2      M    M
 15000  -14.8   5.4   300   18    9  10.2   5.6   15.9  60.7     0.1      M    M
 14500  -13.9   7.0   305   16    8   1.6   0.9   15.4  59.6    -0.4    784  4.0
 14000  -13.5   7.7   305   15    8   5.8   3.2   14.2  57.6    -1.5    757  3.8
 13500  -12.7   9.1   315   13    7   5.2   2.9   13.5  56.2    -2.2    719  3.7
 13000  -12.0  10.4   330   12    6   5.3   2.9   12.7  54.9    -2.9    682  3.5
 12500  -10.9  12.4   340   12    6   9.0   4.9   12.3  54.2    -3.3    635  3.2
 12000   -9.6  14.7   355   12    6   8.8   4.8   12.2  53.9    -3.5    581  3.0
 11500   -8.4  16.9   355   13    7   7.4   4.0   11.9  53.4    -3.8    530  2.7
 11000   -7.3  18.9   355   13    7   7.5   4.1   11.5  52.7    -4.2    483  2.5
 10500   -6.2  20.8   355   14    7   8.8   4.8   11.2  52.1    -4.6    435  2.2
 10250   -5.5  22.1   355   14    7  10.9   6.0   11.2  52.2    -4.6    405  2.1
 10000   -4.7  23.5   355   15    8   7.9   4.3   11.2  52.2    -4.6    375  1.9
  9750   -4.3  24.3   355   14    7   4.2   2.3   10.9  51.6    -4.9    356  1.8
  9500   -4.0  24.8   355   13    7   6.3   3.5   10.5  50.9    -5.3    339  1.7
  9250   -3.4  25.9   360   12    6   8.9   4.9   10.4  50.7    -5.5    314  1.6
  9000   -2.7  27.1   360   10    5   9.0   5.0   10.3  50.6    -5.5    286  1.5
  8750   -2.1  28.2   360    9    4   9.0   4.9   10.3  50.5    -5.6    259  1.3
  8500   -1.4  29.5   005    7    4   9.2   5.0   10.2  50.4    -5.7    231  1.2
  8250   -0.7  30.7   010    6    3   8.4   4.6   10.1  50.3    -5.8    204  1.0
  8000   -0.2  31.6   020    4    2   7.1   3.9   10.0  50.0    -6.0    180  0.9
  7750    0.3  32.5   035    4    2   6.9   3.8    9.8  49.6    -6.2    157  0.8
  7500    0.9  33.6   050    4    2   7.0   3.8    9.6  49.2    -6.4    135  0.7
  7250    1.4  34.5   065    5    3   6.9   3.8    9.3  48.8    -6.7    112  0.6
  7000    1.9  35.4   075    6    3   7.3   4.0    9.1  48.4    -6.9     89  0.5
  6750    2.4  36.3   075    5    2   5.7   3.1    8.9  48.1    -7.2     67  0.3
  6500    2.7  36.9   070    3    2   3.9   2.1    8.5  47.3    -7.6     50  0.3
  6250    3.0  37.4   055    2    1   4.3   2.3    8.1  46.5    -8.1     34  0.2
  6000    3.3  37.9   335    1    0   4.2   2.3    7.7  45.8    -8.5     18  0.1
  5750    3.5  38.3   350    1    0   4.3   2.3    7.2  45.0    -9.0      2  0.0
  5500    3.8  38.8   025    1    1   4.0   2.2    6.8  44.3    -9.5      M    M
  5250    4.1  39.4   040    2    1   4.9   2.7    6.4  43.5    -9.9      M    M
  5000    4.4  39.9   045    3    2  -0.1  -0.1    6.0  42.7   -10.4      M    M

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

           04/26/2017 at 0900 MDT          |       04/26/2017 at 1200 MDT
                                           |
K index... +13.1  LI... +1.5               | K index... +14.9  LI... +1.6
CAPE... +19.6  CIN... -6.6                 | CAPE... +57.3  CIN... -2.9
                                           |
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 -57.3 -71.1  310  37 19   0.9   0.5 | -57.3 -71.1  315  35 18   1.6   0.9
 45000 -55.9 -68.6  315  55 28   1.0   0.6 | -54.9 -66.8  320  53 27   1.8   1.0
 40000 -56.3 -69.3  315  68 35  -0.3  -0.2 | -55.3 -67.5  310  67 34  -0.4  -0.2
 38000 -55.7 -68.3  320  73 38   3.0   1.6 | -55.0 -67.0  310  72 37   1.7   0.9
 36000 -54.0 -65.2  325  81 42   2.9   1.6 | -54.0 -65.2  315  78 40   1.7   0.9
 34000 -52.1 -61.8  330  88 46   5.3   2.9 | -52.9 -63.2  320  84 43   4.7   2.6
 32000 -48.2 -54.8  330  84 43   6.6   3.6 | -49.1 -56.4  315  84 43   6.3   3.5
 30000 -44.3 -47.7  325  79 41   7.6   4.2 | -45.3 -49.5  315  84 43   8.1   4.5
 29000 -41.9 -43.4  325  77 40   7.9   4.3 | -42.7 -44.9  315  83 43   8.6   4.7
 28000 -39.5 -39.1  325  76 39   7.9   4.3 | -39.5 -39.1  315  82 42   8.6   4.7
 27000 -37.2 -35.0  325  74 38   7.9   4.3 | -36.9 -34.4  320  81 42   8.6   4.7
 26000 -34.6 -30.3  320  69 36   6.1   3.3 | -34.4 -29.9  320  79 41   8.1   4.5
 25000 -32.8 -27.0  320  64 33   6.1   3.3 | -32.0 -25.6  325  78 40   8.1   4.5
 24000 -31.0 -23.8  320  58 30   6.2   3.4 | -29.6 -21.3  330  76 39   8.3   4.6
 23000 -29.4 -20.9  315  52 27   5.0   2.8 | -27.6 -17.7  330  69 36   6.1   3.3
 22000 -27.9 -18.2  315  46 24   5.0   2.8 | -25.8 -14.4  330  60 31   6.1   3.3
 21000 -26.4 -15.5  315  40 21   5.1   2.8 | -23.9 -11.0  325  51 26   5.8   3.2
 20000 -24.7 -12.5  310  36 19   6.0   3.3 | -22.6  -8.7  320  44 23   4.3   2.4
 19500 -23.8 -10.8  310  35 18   6.1   3.3 | -21.9  -7.4  320  41 21   4.4   2.4
 19000 -22.9  -9.2  310  34 17   6.1   3.3 | -21.3  -6.3  315  38 20   4.4   2.4
 18500 -22.0  -7.6  305  32 17   6.1   3.3 | -20.6  -5.1  315  35 18   4.3   2.4
 18000 -21.0  -5.8  305  31 16   7.5   4.1 | -19.9  -3.8  310  33 17   5.4   2.9
 17500 -19.9  -3.8  300  31 16   7.4   4.1 | -19.2  -2.6  305  31 16   5.3   2.9
 17000 -18.8  -1.8  300  31 16   6.1   3.3 | -18.4  -1.1  305  29 15   5.1   2.8
 16500 -18.0  -0.4  300  30 16   5.5   3.0 | -17.7   0.1  300  28 14   5.0   2.8
 16000 -17.1   1.2  300  29 15   5.5   3.0 | -17.0   1.4  300  26 14   5.5   3.0
 15500 -16.3   2.7  300  28 14   5.6   3.1 | -16.0   3.2  295  26 13   6.9   3.8
 15000 -15.5   4.1  300  26 14   5.7   3.1 | -15.0   5.0  290  25 13   6.9   3.8
 14500 -14.7   5.5  300  24 13   5.5   3.0 | -14.1   6.6  285  24 12   4.7   2.6
 14000 -13.9   7.0  300  22 11   5.5   3.0 | -13.4   7.9  285  23 12   4.8   2.6
 13500 -13.0   8.6  300  20 10   7.1   3.9 | -12.1  10.2  280  20 10   6.7   3.7
 13000 -11.5  11.3  295  16  8   7.4   4.1 | -11.1  12.0  275  18  9   7.0   3.9
 12500 -10.3  13.5  295  14  7   8.4   4.6 | -10.0  14.0  270  17  9   7.9   4.3
 12000  -9.1  15.6  295  12  6   8.3   4.6 |  -8.9  16.0  270  17  9   7.9   4.4
 11500  -7.9  17.8  300  10  5   8.1   4.5 |  -7.7  18.1  265  17  9   8.2   4.5
 11000  -6.7  19.9  305   8  4   7.6   4.2 |  -6.5  20.3  265  16  8   8.1   4.4
 10500  -5.8  21.6  310   6  3   6.1   3.4 |  -5.3  22.5  265  15  8   7.3   4.0
 10250  -5.3  22.5  310   5  2   7.3   4.0 |  -4.8  23.4  265  15  8   9.3   5.1
 10000  -4.7  23.5  310   4  2   8.2   4.5 |  -4.0  24.8  265  14  7   9.8   5.4
  9750  -4.2  24.4  305   3  2   7.4   4.0 |  -3.4  25.9  265  14  7   7.7   4.2
  9500  -3.6  25.5  295   3  2   7.4   4.1 |  -2.9  26.8  265  13  7   7.6   4.2
  9250  -3.1  26.4  280   3  1   6.8   3.7 |  -2.3  27.9  265  12  6   7.7   4.2
  9000  -2.7  27.1  265   2  1   6.2   3.4 |  -1.7  28.9  265  11  6   7.3   4.0
  8750  -2.2  28.0  255   2  1   6.9   3.8 |  -1.2  29.8  265  10  5   7.0   3.8
  8500  -1.7  28.9  245   2  1   7.2   3.9 |  -0.7  30.7  270   9  5   6.9   3.8
  8250  -1.2  29.8  235   2  1   7.3   4.0 |  -0.2  31.6  270   9  4   7.8   4.3
  8000  -0.6  30.9  225   2  1   6.9   3.8 |   0.4  32.7  270   8  4   9.5   5.2
  7750  -0.2  31.6  220   2  1   5.9   3.3 |   1.1  34.0  270   8  4   9.6   5.3
  7500   0.2  32.4  215   2  1   5.6   3.1 |   1.8  35.2  270   8  4   9.2   5.0
  7250   0.7  33.3  210   2  1   6.2   3.4 |   2.5  36.5  270   8  4  10.0   5.5
  7000   1.2  34.2  205   2  1   6.7   3.7 |   3.3  37.9  275   8  4  10.7   5.9
  6750   1.6  34.9  205   2  1   5.8   3.2 |   4.1  39.4  275   8  4  10.0   5.5
  6500   2.1  35.8  200   2  1   7.5   4.1 |   4.8  40.6  275   8  4  10.5   5.8
  6250   2.8  37.0  205   2  1  10.8   5.9 |   5.6  42.1  275   8  4  11.9   6.5
  6000   3.6  38.5  205   2  1  11.0   6.0 |   6.5  43.7  275   8  4  12.0   6.6
  5750   4.4  39.9  205   2  1   9.8   5.4 |   7.4  45.3  275   7  4  11.6   6.4
  5500   5.1  41.2  210   2  1   9.9   5.5 |   8.4  47.1  275   7  4  15.0   8.2
  5250   5.9  42.6  210   2  1  11.4   6.3 |   9.7  49.5  275   7  4  20.5  11.2
  5000     M     M    M   M  M     M     M |     M     M    M   M  M     M     M

           04/26/2017 at 1500 MDT          |       04/26/2017 at 1800 MDT
                                           |
K index... +13.3  LI... +3.6               | K index... +19.6  LI... +2.8
CAPE... 0.0  CIN... -0.1                   | 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 -57.4 -71.3  310  38 20   2.3   1.3 | -57.2 -71.0  305  43 22   2.4   1.3
 45000 -53.9 -65.0  320  51 26   2.7   1.5 | -53.6 -64.5  310  55 28   2.6   1.4
 40000 -55.7 -68.3  310  72 37  -1.3  -0.7 | -53.3 -63.9  300  69 36   0.1   0.0
 38000 -55.6 -68.1  305  81 42   2.3   1.3 | -53.6 -64.5  300  72 37  -1.2  -0.7
 36000 -54.2 -65.6  310  89 46   2.3   1.3 | -54.3 -65.7  295  70 36  -1.2  -0.7
 34000 -52.7 -62.9  310  96 49   5.2   2.8 | -55.0 -67.0  295  68 35   2.4   1.3
 32000 -48.9 -56.0  310  83 43   6.4   3.5 | -51.1 -60.0  290  61 32   6.6   3.6
 30000 -45.1 -49.2  305  70 36   7.6   4.2 | -47.1 -52.8  290  55 28   8.3   4.6
 29000 -42.1 -43.8  305  66 34   7.9   4.3 | -43.7 -46.7  290  52 27   9.1   5.0
 28000 -39.8 -39.6  305  63 33   7.9   4.3 | -41.0 -41.8  285  50 26   9.1   5.0
 27000 -37.4 -35.3  305  61 31   7.9   4.4 | -38.3 -36.9  285  48 25   9.1   5.0
 26000 -34.9 -30.8  305  60 31   8.4   4.6 | -35.7 -32.3  285  45 23   8.5   4.6
 25000 -32.4 -26.3  305  60 31   8.4   4.6 | -33.2 -27.8  285  42 21   8.5   4.6
 24000 -29.9 -21.8  305  59 31   8.6   4.7 | -30.7 -23.3  285  38 20   8.6   4.7
 23000 -27.8 -18.0  310  53 28   6.8   3.8 | -28.3 -18.9  285  37 19   7.8   4.3
 22000 -25.7 -14.3  315  46 24   6.8   3.8 | -26.0 -14.8  285  35 18   7.8   4.3
 21000 -23.7 -10.7  325  40 20   6.9   3.8 | -23.7 -10.7  285  34 18   7.6   4.2
 20000 -21.5  -6.7  320  38 19   7.2   4.0 | -21.6  -6.9  285  33 17   6.9   3.8
 19500 -20.5  -4.9  315  38 19   7.2   4.0 | -20.6  -5.1  285  32 17   6.9   3.8
 19000 -19.4  -2.9  310  37 19   7.2   4.0 | -19.6  -3.3  285  32 16   6.9   3.8
 18500 -18.3  -0.9  305  38 19   7.3   4.0 | -18.6  -1.5  285  31 16   7.0   3.8
 18000 -17.3   0.9  305  38 19   6.1   3.3 | -17.6   0.3  285  31 16   5.8   3.2
 17500 -16.4   2.5  305  38 19   6.2   3.4 | -16.8   1.8  290  31 16   5.9   3.2
 17000 -15.5   4.1  305  37 19   4.2   2.3 | -15.9   3.4  290  30 16   5.8   3.2
 16500 -15.1   4.8  305  35 18   3.4   1.8 | -15.1   4.8  290  29 15   5.7   3.1
 16000 -14.6   5.7  305  34 17   3.5   1.9 | -14.2   6.4  290  28 15   5.6   3.1
 15500 -14.0   6.8  305  31 16   4.4   2.4 | -13.4   7.9  290  27 14   5.1   2.8
 15000 -13.4   7.9  300  29 15   4.2   2.3 | -12.7   9.1  285  25 13   5.0   2.7
 14500 -12.6   9.3  300  27 14   6.6   3.6 | -11.8  10.8  285  24 12   7.3   4.0
 14000 -11.7  10.9  295  25 13   6.4   3.5 | -10.2  13.6  275  22 11   7.1   3.9
 13500 -10.1  13.8  290  22 12   7.3   4.0 |  -9.2  15.4  270  21 11   7.1   3.9
 13000  -9.1  15.6  285  21 11   7.3   4.0 |  -8.2  17.2  265  20 10   7.0   3.8
 12500  -8.0  17.6  280  20 10   7.4   4.1 |  -7.2  19.0  265  20 10   6.3   3.4
 12000  -6.9  19.6  270  19 10   7.5   4.1 |  -6.3  20.7  260  21 11   6.2   3.4
 11500  -5.7  21.7  265  18  9   8.2   4.5 |  -5.5  22.1  260  20 10   5.5   3.0
 11000  -4.5  23.9  260  17  9   8.1   4.4 |  -4.7  23.5  260  20 10   5.4   3.0
 10500  -3.3  26.1  255  16  8   7.8   4.3 |  -3.9  25.0  260  19 10   4.3   2.4
 10250  -2.8  27.0  255  15  8   8.5   4.7 |  -3.6  25.5  265  18  9   5.3   2.9
 10000  -2.1  28.2  255  14  7   9.2   5.0 |  -3.1  26.4  265  18  9   7.9   4.3
  9750  -1.4  29.5  255  13  7   8.6   4.7 |  -2.4  27.7  270  18  9   9.7   5.3
  9500  -0.8  30.6  255  12  6   8.6   4.7 |  -1.7  28.9  270  18  9  10.1   5.5
  9250  -0.2  31.6  255  11  6   8.2   4.5 |  -0.9  30.4  270  18  9   9.6   5.3
  9000   0.4  32.7  255  10  5   8.8   4.8 |  -0.2  31.6  270  18  9   9.2   5.1
  8750   1.1  34.0  255  10  5  10.0   5.5 |   0.5  32.9  270  18  9  10.0   5.5
  8500   1.8  35.2  255  10  5   9.5   5.2 |   1.2  34.2  270  18  9  10.0   5.5
  8250   2.6  36.7  255  10  5  10.7   5.9 |   2.0  35.6  270  18  9  11.0   6.0
  8000   3.4  38.1  255  10  5  11.5   6.3 |   2.9  37.2  270  18  9  11.7   6.4
  7750   4.2  39.6  255   9  5   9.9   5.4 |   3.7  38.7  270  18  9   9.8   5.4
  7500   4.9  40.8  255   9  5   9.3   5.1 |   4.4  39.9  270  18  9   8.8   4.8
  7250   5.6  42.1  255   9  5   9.4   5.2 |   5.0  41.0  270  18  9   9.6   5.3
  7000   6.3  43.3  255   9  5   9.6   5.3 |   5.8  42.4  270  18  9  10.2   5.6
  6750   7.1  44.8  255   9  5  10.1   5.6 |   6.6  43.9  270  18  9   9.9   5.4
  6500   7.8  46.0  255   9  5  10.4   5.7 |   7.3  45.1  270  17  9   9.8   5.4
  6250   8.6  47.5  255   9  4  11.0   6.0 |   8.0  46.4  270  17  9  10.5   5.7
  6000   9.5  49.1  260   8  4  11.8   6.5 |   8.9  48.0  270  17  9  10.9   6.0
  5750  10.4  50.7  260   8  4  10.8   5.9 |   9.7  49.5  270  16  8  11.5   6.3
  5500  11.2  52.2  260   8  4  14.4   7.9 |  10.5  50.9  270  14  7  10.1   5.5
  5250  12.6  54.7  260   8  4  23.2  12.7 |  11.1  52.0  275  14  7   5.6   3.1
  5000     M     M    M   M  M     M     M |     M     M    M   M  M     M     M
________________________________________________________________________________

This product is issued twice per day, once by approximately 0630 MST/0730 MDT
(1330 UTC) and again by approximately 1830 MST/1930 MDT (0130 UTC).  It is not
continuously monitored nor updated after its initial issuance.

The information contained herein is based on rawinsonde observation and/or
numerical weather prediction model data taken at Walker Field in Grand
Junction, Colorado at

                   North Latitude:  39 deg 07 min 00.001 sec
                   West Longitude: 108 deg 31 min 59.998 sec
                   Elevation: 4839 feet (1475 meters)

and may not be representative of other areas along the Western Slope of
Colorado.  Note that some elevations in numerical weather prediction models
differ from actual station elevations, which can lead to data which appear
to be below ground.  Erroneous data such as these should not be used.

The content and format of this report as well as the issuance times are subject
to change without prior notice.  Comments and suggestions are welcome and should
be directed to one of the addresses or phone numbers shown at the bottom of this
page.  To expedite a response to comments, be sure to mention your interest in
the soaring forecast.

DEFINITIONS:

CAPE (Convective Available Potential Energy) - An integrated measure of the
     energy available for convective development, also known as the positive
     area on a thermodynamic diagram.  Units are Joules per kilogram.  Larger
     values are indicative of greater instability and the possibility of
     stronger convective activity, including thunderstorms.  Values around or
     greater than 1000 suggest the possibility of severe weather should
     convective activity develop.

CIN (Convective Inhibition) - An integrated measure of the amount of energy
     needed to initiate convective activity, also known as the negative area on
     a thermodynamic diagram.  Units are Joules per kilogram.  The more negative
     this number, the more energy is required to initiate convection.  This
     inhibitive energy can be overcome through surface heating, cooling aloft,
     lifting mechanisms (orographic, frontal, gravity waves, etc.)

Convective Condensation Level - The height to which an air parcel possessing the
     average saturation mixing ratio in the lowest 4000 feet of the airmass,
     if heated sufficiently from below, will rise dry adiabatically until it
     just becomes saturated.  It estimates the base of cumulus clouds that are
     produced by surface heating only.

Convection Temperature (ConvectionT) - The surface temperature required to make
     the airmass dry adiabatic up to the given level.  It can be considered a
     "trigger temperature" for that level.

Freezing Level - The height where the temperature is zero degrees Celsius.

Height of Stable Layer - The height (between 12,000 and 18,000 feet above
     mean sea level) where the smallest lapse rate exists.  The location and
     existence of this feature is important in the generation of mountain
     waves.

K Index - A measure of stability which combines the temperature difference
     between approximately 5,000 and 18,000 feet above the surface, the amount
     of moisture at approximately 5,000 feet above the surface, and a measure
     of the dryness at approximately 10,000 feet above the surface.  Larger
     positive numbers indicate more instability and a greater likelihood of
     thunderstorm development.  One interpretation of K index values regarding
     soaring in the western United States is given in WMO Technical Note 158
     and is reproduced in the following table:

          below -10    no or weak thermals
           -10 to 5    dry thermals or 1/8 cumulus with moderate thermals
            5 to 15    good soaring conditions
           15 to 20    good soaring conditions with occasional showers
           20 to 30    excellent soaring conditions, but increasing
                       probability of showers and thunderstorms
           above 30    more than 60 percent probability of thunderstorms

Lapse Rate - The change with height of the temperature. Negative values indicate
     inversions.

Lifted Condensation Level - The height to which an air parcel possessing the
     average dew point in the lowest 4000 feet of the airmass and the forecast
     maximum temperature must be lifted dry adiabatically to attain saturation.

Lifted Index (LI) - The difference between the environmental temperature at a
     level approximately 18,000 feet above the surface and the temperature of
     an air parcel lifted dry adiabatically from the surface to its lifted
     condensation level and then pseudoadiabatically thereafter to this same
     level.  The parcel`s initial temperature is the forecast maximum
     temperature and its dew point is the average dew point in the lowest 4000
     feet of the airmass.  Negative values are indicative of instability with
     positive values showing stable conditions.

Lift Rate - An experimental estimate of the strength of thermals.  It is
     computed the same way as the maximum rate of lift but uses the actual
     level rather than the maximum height of thermals in the calculation.
     Also, none of the empirical adjustments based on cloudiness and K-index
     are applied to these calculations.

Maximum Height of Thermals - The height where the dry adiabat through the
     forecast maximum temperature intersects the environmental temperature.

Maximum Rate of Lift - An estimate of the maximum strength of thermals.  It
     is computed from an empirical formula which combines the expected maximum
     height of thermals with the difference in the environmental temperatures
     between the maximum height of thermals and the temperature 4,000 feet
     above the ground.  After this computation, further empirical adjustments
     are made based on the value of the K-index and the amount and opacity of
     middle and high level cloudiness expected between the time of trigger
     temperature and the time of overdevelopment.

Middle/High Clouds - The amount and opacity of middle (altostratus, altocumulus)
     or high (cirrus, cirrostratus, cirrocumulus) clouds.  Broken means that
     between 60% and 90% of the sky is covered by the cloud, with overcast
     conditions occurring when more than 90% of the sky is covered by the cloud.
     Thin implies that the clouds are predominantly transparent, meaning that
     some sunlight is reaching the ground, in contrast to opaque which suggests
     that little sunlight is reaching the ground.

Potential Height of Wave - The minimum of the following two heights:
     1. Level above the height of stable layer (or 14,000 feet if none exists)
        where the wind direction changes by 30 degrees or more
     2. Level above the height of stable layer (or 14,000 feet if none exists)
        where the wind speed no longer increases with height

PVA/NVA - Positive vorticity advection (PVA)/negative vorticity advection (NVA)
     on the 500 millibar isobaric surface (approximately 18,000 feet above mean
     sea level).  Weak PVA has been shown to assist in mountain wave soaring.

Soaring Window - The time between the time the trigger temperature is reached
                 and the time of overdevelopment.

Thermal Index - The difference between the environmental temperature and the
     temperature at a particular level determined by following the dry adiabat
     through the forecast maximum temperature up to that level.  Negative values
     are indicative of thermal lift.

Thermal Soaring Index - An adjective rating (for sailplanes) based on the
     computed maximum rate of lift, and the wind speed and middle and high
     cloud cover expected during the soaring window (the time of the trigger
     temperature and the time of overdevelopment) according to the following:

                 Maximum rate of lift        Adjective Rating
                      >= 800 fpm                 Excellent
                 >= 400 and < 800 fpm              Good
                 >= 200 and < 400 fpm              Fair
                       < 200 fpm                   Poor

Time of Overdevelopment - The time one or more of the following phenomena,
     which essentially shut off thermal lift, is expected to occur:
     1. formation of broken to overcast convective cloud cover
     2. formation of scattered to numerous downbursts
     3. initiation of widespread precipitation

Time of Trigger Temperature - The time the surface temperature is expected to
     reach the trigger temperature.

Trigger Temperature - The surface temperature required to make the first 4000
     feet of the atmosphere dry adiabatic.

Wave Soaring Index - An empirical, adjective rating (for sailplanes) which
     attempts to combine a variety of phenomena important in mountain wave
     soaring into a single index number.  Objective points are assigned to
     these phenomena: wind speed and direction at 14,000 ft MSL, the static
     stability in the 12,000-18,000 ft MSL layer, the wind speed gradient above
     the stable layer, jet stream location and frontal and upper trough
     movements.

042613



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