Soaring Guidance
Issued by NWS Grand Junction, CO

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000
UXUS97 KGJT 301235
SRGGJT

Soaring Forecast
National Weather Service Grand Junction, Colorado
0635 MDT Sunday, April 30, 2017

This forecast is for Sunday, April 30, 2017:

If the trigger temperature of 45.8 F/7.7 C is reached...then
   Thermal Soaring Index....................... Excellent
   Maximum rate of lift........................ 854 ft/min (4.3 m/s)
   Maximum height of thermals.................. 16004 ft MSL (11165 ft AGL)

Forecast maximum temperature................... 63.0 F/17.7 C
Time of trigger temperature.................... 1145 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................. 13517 ft MSL (8678 ft AGL)
Thermal soaring outlook for Monday 05/01....... Excellent

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

Remarks...

Sunrise/Sunset.................... 06:16:50 / 20:05:34 MDT
Total possible sunshine........... 13 hr 48 min 44 sec (828 min 44 sec)
Altitude of sun at 13:11:22 MDT... 65.89 degrees

Upper air data from rawinsonde observation taken on 04/30/2017 at 0600 MDT

Freezing level.................. 7074 ft MSL (2235 ft AGL)
Convective condensation level... 15888 ft MSL (11049 ft AGL)
Lifted condensation level....... 16274 ft MSL (11435 ft AGL)
Lifted index.................... +6.5
K index......................... -11.6

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  -58.5 -73.3   315   39   20   3.5   1.9  104.7 220.5    49.7      M    M
 45000  -53.9 -65.0   320   47   24   2.3   1.2   86.4 187.4    42.2      M    M
 40000  -49.3 -56.7   305   57   29 -15.5  -8.5   70.7 159.3    34.8      M    M
 38000  -56.2 -69.2   340   58   30   6.0   3.3   51.4 124.6    22.9      M    M
 36000  -52.3 -62.1   360   55   28   7.3   4.0   48.4 119.1    21.4      M    M
 34000  -51.3 -60.3   350   63   32   4.5   2.5   41.5 106.7    17.1      M    M
 32000  -50.2 -58.4   350   74   38   9.1   5.0   33.7  92.7    12.0      M    M
 30000  -45.1 -49.2   355   76   39   7.6   4.2   32.7  90.9    11.6      M    M
 29000  -42.9 -45.2   355   72   37   7.6   4.2   31.8  89.3    11.0      M    M
 28000  -40.6 -41.1   355   69   36   7.9   4.3   31.0  87.8    10.6      M    M
 27000  -38.0 -36.4   360   66   34   8.9   4.9   30.6  87.0    10.3      M    M
 26000  -35.3 -31.5   360   62   32   8.9   4.9   30.2  86.4    10.2      M    M
 25000  -32.6 -26.7   360   59   30   8.9   4.9   30.0  86.1    10.2      M    M
 24000  -30.0 -22.0   360   57   29   8.9   4.9   29.7  85.4    10.0      M    M
 23000  -27.3 -17.1   360   57   29   8.9   4.9   29.2  84.6     9.8      M    M
 22000  -24.6 -12.3   360   56   29   8.9   4.9   28.9  84.0     9.6      M    M
 21000  -22.0  -7.6   355   56   29   7.0   3.8   28.6  83.5     9.5      M    M
 20000  -20.3  -4.5   355   56   29   5.6   3.1   27.2  80.9     8.4      M    M
 19500  -19.3  -2.7   360   54   28   7.6   4.2   26.6  79.9     7.9      M    M
 19000  -18.2  -0.8   010   51   26   7.7   4.2   26.2  79.2     7.6      M    M
 18500  -17.2   1.0   010   49   25   4.2   2.3   25.6  78.1     7.2      M    M
 18000  -16.6   2.1   005   45   23   0.7   0.4   24.7  76.4     6.4      M    M
 17500  -17.7   0.1   355   42   21  -0.7  -0.4   20.9  69.6     3.2      M    M
 17000  -17.3   0.9   350   39   20   2.1   1.1   19.6  67.3     2.1      M    M
 16500  -17.0   1.4   350   36   19   2.2   1.2   18.3  65.0     1.0      M    M
 16000  -16.7   1.9   350   34   17   3.6   2.0   17.0  62.5    -0.2    850  4.3
 15500  -15.7   3.7   345   31   16   7.5   4.1   16.4  61.6    -0.7    805  4.1
 15000  -14.6   5.7   345   29   15   7.4   4.1   16.1  60.9    -1.1    757  3.8
 14500  -13.5   7.7   350   26   13   6.7   3.7   15.7  60.2    -1.4    709  3.6
 14000  -12.8   9.0   350   23   12   3.8   2.1   14.9  58.7    -2.2    674  3.4
 13500  -12.3   9.9   360   22   11   4.0   2.2   13.9  57.0    -3.1    642  3.3
 13000  -11.7  10.9   005   22   11   3.8   2.1   13.0  55.3    -4.0    610  3.1
 12500  -11.1  12.0   020   25   13   1.4   0.7   12.0  53.6    -4.9    578  2.9
 12000  -11.1  12.0   030   28   14   3.5   1.9   10.5  51.0    -6.4    563  2.9
 11500  -10.2  13.6   025   28   14   8.5   4.7   10.0  50.0    -7.0    520  2.6
 11000   -8.9  16.0   020   28   15   9.5   5.2    9.9  49.7    -7.2    466  2.4
 10500   -7.5  18.5   020   29   15   9.0   4.9    9.8  49.6    -7.3    409  2.1
 10250   -6.8  19.8   015   29   15  11.1   6.1    9.8  49.6    -7.3    380  1.9
 10000   -6.0  21.2   010   29   15   6.9   3.8    9.9  49.8    -7.3    350  1.8
  9750   -5.8  21.6   010   27   14   0.1   0.1    9.3  48.7    -7.9    338  1.7
  9500   -5.7  21.7   010   24   12   2.8   1.5    8.6  47.5    -8.5    328  1.7
  9250   -5.4  22.3   010   22   11   7.0   3.8    8.2  46.8    -8.9    309  1.6
  9000   -4.8  23.4   010   19   10   8.3   4.6    8.1  46.6    -9.0    284  1.4
  8750   -4.2  24.4   010   17    9   8.0   4.4    8.0  46.3    -9.2    259  1.3
  8500   -3.6  25.5   010   15    8   8.1   4.4    7.8  46.1    -9.3    233  1.2
  8250   -3.0  26.6   005   13    7   8.0   4.4    7.7  45.9    -9.5    208  1.1
  8000   -2.4  27.7   005   11    6   8.0   4.4    7.6  45.7    -9.6    182  0.9
  7750   -1.8  28.8   005   10    5   8.0   4.4    7.5  45.4    -9.8    157  0.8
  7500   -1.2  29.8   005    8    4   8.0   4.4    7.3  45.2    -9.9    131  0.7
  7250   -0.6  30.9   010    7    3   8.0   4.4    7.2  45.0   -10.1    106  0.5
  7000    0.1  32.2   010    5    3   8.0   4.4    7.1  44.7   -10.2     80  0.4
  6750    0.7  33.3   360    5    2   8.0   4.4    6.9  44.5   -10.4     55  0.3
  6500    1.3  34.3   340    4    2   8.0   4.4    6.8  44.2   -10.6     30  0.2
  6250    1.9  35.4   325    4    2   8.0   4.4    6.7  44.0   -10.7      4  0.0
  6000    2.5  36.5   310    5    2   8.0   4.4    6.5  43.8   -10.9      M    M
  5750    3.1  37.6   310    4    2   8.1   4.4    6.4  43.5   -11.1      M    M
  5500    3.7  38.7   330    3    2   7.9   4.3    6.3  43.3   -11.2      M    M
  5250    4.2  39.6   360    2    1   6.0   3.3    6.1  42.9   -11.4      M    M
  5000    4.2  39.6   030    3    1 -10.4  -5.7    5.3  41.6   -12.2      M    M

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

           04/30/2017 at 0900 MDT          |       04/30/2017 at 1200 MDT
                                           |
K index... -11.8  LI... +9.2               | K index... -3.0  LI... +8.0
CAPE... 0.0  CIN... 0.0                    | CAPE... +0.3  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 -56.2 -69.2  310  34 17   1.3   0.7 | -57.1 -70.8  310  36 19   1.6   0.9
 45000 -54.2 -65.6  320  46 24   0.6   0.3 | -54.7 -66.5  320  46 23  -1.2  -0.6
 40000 -56.2 -69.2  340  55 28  -1.3  -0.7 | -56.7 -70.1  335  57 30  -1.3  -0.7
 38000 -56.0 -68.8  345  59 30   1.9   1.0 | -56.2 -69.2  335  61 31   2.6   1.4
 36000 -54.8 -66.6  345  64 33   1.9   1.0 | -54.6 -66.3  335  63 32   2.6   1.4
 34000 -53.1 -63.6  350  67 35   8.3   4.5 | -52.5 -62.5  340  64 33   8.1   4.4
 32000 -48.5 -55.3  350  63 33   7.8   4.3 | -47.8 -54.0  340  63 32   7.8   4.3
 30000 -43.8 -46.8  350  59 30   7.2   3.9 | -42.4 -44.3  345  58 30   8.5   4.7
 29000 -41.7 -43.1  350  54 28   7.2   4.0 | -39.9 -39.8  340  53 27   8.5   4.7
 28000 -39.0 -38.2  355  49 25   7.2   4.0 | -37.3 -35.1  340  47 24   8.5   4.7
 27000 -36.8 -34.2  355  45 23   8.0   4.4 | -34.8 -30.6  340  42 22   7.0   3.8
 26000 -34.3 -29.7  355  43 22   8.2   4.5 | -32.9 -27.2  335  39 20   6.5   3.6
 25000 -31.8 -25.2  355  41 21   8.2   4.5 | -31.0 -23.8  335  36 19   6.5   3.6
 24000 -29.3 -20.7  355  40 20   8.2   4.5 | -29.0 -20.2  335  33 17   6.9   3.8
 23000 -26.9 -16.4  355  39 20   8.2   4.5 | -26.8 -16.2  335  33 17   7.4   4.1
 22000 -24.5 -12.1  355  39 20   8.2   4.5 | -24.6 -12.3  335  33 17   7.4   4.1
 21000 -22.1  -7.8  355  39 20   7.2   3.9 | -22.4  -8.3  335  33 17   7.6   4.1
 20000 -20.0  -4.0  355  39 20   6.9   3.8 | -20.1  -4.2  335  32 17   7.6   4.2
 19500 -18.9  -2.0  355  38 20   6.9   3.8 | -19.0  -2.2  340  32 17   7.6   4.2
 19000 -17.9  -0.2  355  38 20   6.9   3.8 | -17.8  -0.0  340  32 17   7.6   4.2
 18500 -16.9   1.6  360  38 19   6.7   3.7 | -16.7   1.9  340  32 16   7.2   3.9
 18000 -15.9   3.4  355  38 19   6.5   3.6 | -15.7   3.7  340  32 16   6.9   3.8
 17500 -14.9   5.2  355  38 20   6.5   3.6 | -14.7   5.5  340  32 17   6.9   3.8
 17000 -14.0   6.8  355  38 20   5.5   3.0 | -13.7   7.3  340  32 17   5.8   3.2
 16500 -13.2   8.2  355  38 19   5.7   3.1 | -12.8   9.0  340  32 17   5.9   3.2
 16000 -12.4   9.7  355  38 19   4.3   2.4 | -11.9  10.6  345  33 17   5.9   3.2
 15500 -11.8  10.8  355  37 19   3.9   2.1 | -11.1  12.0  345  33 17   5.8   3.2
 15000 -11.2  11.8  355  37 19   2.4   1.3 | -10.2  13.6  345  33 17   5.1   2.8
 14500 -11.1  12.0  355  35 18   0.4   0.2 |  -9.2  15.4  350  33 17   4.4   2.4
 14000 -11.1  12.0  350  33 17   0.4   0.2 |  -8.7  16.3  350  33 17   1.6   0.9
 13500 -11.0  12.2  355  29 15   0.9   0.5 |  -8.5  16.7  350  32 17   1.2   0.6
 13000 -10.7  12.7  355  27 14   4.2   2.3 |  -8.4  16.9  355  31 16   0.5   0.3
 12500 -10.0  14.0  360  26 13   5.4   2.9 |  -8.4  16.9  355  28 14   0.4   0.2
 12000  -9.1  15.6  360  24 13   6.8   3.7 |  -8.3  17.1  360  24 12   3.1   1.7
 11500  -8.1  17.4  005  24 12   7.3   4.0 |  -7.7  18.1  005  20 10   4.3   2.3
 11000  -7.0  19.4  005  24 12   7.2   3.9 |  -7.1  19.2  010  17  9   6.1   3.4
 10500  -6.0  21.2  005  24 13   7.9   4.3 |  -6.1  21.0  010  14  7   7.4   4.0
 10250  -5.5  22.1  005  25 13   3.9   2.2 |  -5.7  21.7  010  13  7   3.7   2.0
 10000  -5.4  22.3  005  25 13   3.9   2.1 |  -5.5  22.1  005  11  6   5.3   2.9
  9750  -4.9  23.2  005  25 13   7.7   4.2 |  -4.8  23.4  005  10  5   9.9   5.5
  9500  -4.3  24.3  005  25 13   7.2   3.9 |  -4.1  24.6  360   9  5   9.1   5.0
  9250  -3.8  25.2  005  25 13   5.6   3.1 |  -3.5  25.7  360   8  4   7.7   4.2
  9000  -3.5  25.7  005  24 13   3.8   2.1 |  -3.0  26.6  355   7  4   7.4   4.1
  8750  -3.2  26.2  005  23 12   4.8   2.6 |  -2.3  27.9  350   6  3   9.6   5.3
  8500  -2.9  26.8  005  21 11   4.7   2.6 |  -1.6  29.1  345   6  3   9.5   5.2
  8250  -2.5  27.5  005  19 10   4.4   2.4 |  -0.9  30.4  340   5  3   8.9   4.9
  8000  -2.2  28.0  005  16  8   4.3   2.3 |  -0.2  31.6  340   5  3   8.9   4.9
  7750  -1.9  28.6  005  13  7   4.4   2.4 |   0.4  32.7  335   5  2   9.5   5.2
  7500  -1.5  29.3  010  10  5   4.0   2.2 |   1.2  34.2  330   4  2  10.0   5.5
  7250  -1.3  29.7  010   8  4   3.7   2.0 |   1.9  35.4  330   4  2  10.5   5.8
  7000  -1.0  30.2  005   6  3   3.4   1.9 |   2.7  36.9  325   4  2  10.2   5.6
  6750  -0.7  30.7  005   4  2   4.9   2.7 |   3.5  38.3  320   4  2  10.0   5.5
  6500  -0.2  31.6  005   3  2   8.9   4.9 |   4.2  39.6  315   4  2  10.7   5.9
  6250   0.5  32.9  360   3  1  10.7   5.9 |   5.1  41.2  315   4  2  12.1   6.7
  6000   1.3  34.3  360   2  1   8.9   4.9 |   6.0  42.8  310   3  2   9.4   5.2
  5750   1.9  35.4  355   2  1  10.0   5.5 |   6.7  44.1  305   3  2  12.5   6.8
  5500   2.8  37.0  355   2  1  12.6   6.9 |   7.9  46.2  310   3  2  18.3  10.0
  5250   3.7  38.7  355   2  1  10.5   5.8 |   9.1  48.4  315   4  2  13.7   7.5
  5000     M     M    M   M  M     M     M |     M     M    M   M  M     M     M

           04/30/2017 at 1500 MDT          |       04/30/2017 at 1800 MDT
                                           |
K index... +6.4  LI... +6.4                | K index... +11.3  LI... +4.2
CAPE... +0.3  CIN... -0.3                  | 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 -58.1 -72.6  315  38 20   0.9   0.5 | -58.4 -73.1  315  37 19   0.1   0.1
 45000 -56.7 -70.1  325  47 24  -0.7  -0.4 | -58.3 -72.9  325  47 24  -0.9  -0.5
 40000 -57.7 -71.9  335  61 31  -0.6  -0.4 | -59.4 -74.9  340  73 38  -0.8  -0.4
 38000 -56.6 -69.9  335  65 34   3.6   2.0 | -57.5 -71.5  340  79 41   5.6   3.1
 36000 -54.5 -66.1  335  68 35   3.6   2.0 | -54.1 -65.4  340  83 43   5.6   3.1
 34000 -51.8 -61.2  340  70 36   8.1   4.4 | -50.3 -58.5  340  85 44   8.3   4.6
 32000 -47.0 -52.6  340  67 35   8.0   4.4 | -45.3 -49.5  340  82 42   8.4   4.6
 30000 -41.5 -42.7  340  63 32   8.1   4.4 | -39.7 -39.5  345  76 39   8.1   4.4
 29000 -39.1 -38.4  340  58 30   8.1   4.4 | -37.2 -35.0  345  70 36   8.1   4.4
 28000 -36.7 -34.1  340  53 27   8.1   4.4 | -34.8 -30.6  345  65 33   8.1   4.4
 27000 -34.3 -29.7  340  49 25   8.1   4.4 | -32.4 -26.3  345  59 30   7.6   4.2
 26000 -31.8 -25.2  335  46 24   8.1   4.4 | -30.2 -22.4  340  52 27   7.6   4.2
 25000 -29.4 -20.9  330  43 22   8.1   4.4 | -27.9 -18.2  330  46 23   7.6   4.2
 24000 -27.0 -16.6  325  41 21   6.7   3.7 | -25.6 -14.1  320  40 21   6.1   3.3
 23000 -25.5 -13.9  325  41 21   5.2   2.9 | -24.2 -11.6  320  41 21   4.8   2.7
 22000 -23.9 -11.0  325  41 21   5.2   2.9 | -22.8  -9.0  315  42 22   4.8   2.7
 21000 -22.3  -8.1  325  40 21   7.5   4.1 | -21.3  -6.3  315  43 22   4.8   2.7
 20000 -19.9  -3.8  330  37 19   7.9   4.3 | -19.9  -3.8  320  40 21   4.9   2.7
 19500 -18.7  -1.7  330  35 18   7.9   4.3 | -19.2  -2.6  320  39 20   4.9   2.7
 19000 -17.5   0.5  330  33 17   7.9   4.3 | -18.5  -1.3  325  37 19   4.9   2.7
 18500 -16.4   2.5  335  32 16   7.6   4.2 | -17.8  -0.0  325  36 19   6.0   3.3
 18000 -15.3   4.5  335  32 17   7.4   4.1 | -16.8   1.8  330  36 18   6.6   3.6
 17500 -14.2   6.4  335  33 17   7.4   4.1 | -15.8   3.6  330  36 18   6.7   3.7
 17000 -13.3   8.1  335  33 17   5.3   2.9 | -14.9   5.2  335  35 18   5.9   3.2
 16500 -12.5   9.5  335  33 17   5.6   3.0 | -14.0   6.8  335  35 18   6.0   3.3
 16000 -11.7  10.9  335  33 17   4.1   2.3 | -13.2   8.2  335  34 18   4.8   2.6
 15500 -11.1  12.0  340  33 17   3.8   2.1 | -12.5   9.5  335  33 17   4.7   2.6
 15000 -10.6  12.9  340  33 17   3.4   1.9 | -11.8  10.8  340  32 16   5.2   2.9
 14500 -10.1  13.8  340  32 17   2.9   1.6 | -11.0  12.2  340  30 15   5.7   3.1
 14000  -9.5  14.9  345  30 16   3.2   1.8 |  -9.6  14.7  340  27 14   6.6   3.6
 13500  -9.0  15.8  345  27 14   3.2   1.8 |  -8.7  16.3  335  24 12   6.5   3.6
 13000  -8.5  16.7  345  24 12   4.3   2.4 |  -7.6  18.3  335  22 11   7.8   4.3
 12500  -7.8  18.0  345  21 11   4.6   2.5 |  -6.4  20.5  335  20 10   8.1   4.5
 12000  -7.1  19.2  345  18  9   6.5   3.6 |  -5.2  22.6  330  18  9   8.5   4.6
 11500  -6.1  21.0  345  16  8   7.2   3.9 |  -3.9  25.0  325  17  9   8.6   4.7
 11000  -5.0  23.0  340  14  7   8.1   4.4 |  -2.6  27.3  325  15  8   8.6   4.7
 10500  -3.8  25.2  335  12  6   9.2   5.0 |  -1.3  29.7  315  14  7   9.4   5.2
 10250  -3.1  26.4  330  11  6   4.9   2.7 |  -0.7  30.7  315  13  7   5.5   3.0
 10000  -2.9  26.8  325  10  5   5.4   3.0 |  -0.4  31.3  310  13  7   5.8   3.2
  9750  -2.2  28.0  320   9  5  10.0   5.5 |   0.3  32.5  305  12  6   9.9   5.4
  9500  -1.5  29.3  315   9  4   9.0   4.9 |   1.0  33.8  300  12  6   9.1   5.0
  9250  -0.9  30.4  305   8  4   8.7   4.7 |   1.6  34.9  295  11  6   8.1   4.5
  9000  -0.3  31.5  300   8  4   8.2   4.5 |   2.2  36.0  290  11  6   7.0   3.9
  8750   0.4  32.7  295   7  4   8.6   4.7 |   2.7  36.9  285  11  5   7.6   4.2
  8500   1.0  33.8  290   7  4   8.5   4.7 |   3.3  37.9  280  10  5   7.4   4.1
  8250   1.7  35.1  280   7  4   9.9   5.5 |   3.8  38.8  275  10  5   7.9   4.3
  8000   2.5  36.5  280   7  3  10.7   5.9 |   4.4  39.9  270  10  5   8.4   4.6
  7750   3.2  37.8  275   7  3  10.2   5.6 |   5.1  41.2  270   9  5   8.3   4.6
  7500   4.0  39.2  270   7  3  10.0   5.5 |   5.7  42.3  270   9  5   9.1   5.0
  7250   4.7  40.5  270   7  3   9.7   5.3 |   6.4  43.5  265   9  5  10.6   5.8
  7000   5.5  41.9  270   6  3   9.8   5.4 |   7.2  45.0  265   9  5  10.5   5.8
  6750   6.2  43.2  265   6  3  10.5   5.8 |   8.0  46.4  265   9  5   9.0   5.0
  6500   7.0  44.6  265   6  3  11.0   6.0 |   8.7  47.7  265   9  5  10.0   5.5
  6250   7.9  46.2  260   6  3  11.6   6.4 |   9.5  49.1  265   9  5  11.4   6.3
  6000   8.7  47.7  260   6  3   9.7   5.3 |  10.3  50.5  260   9  4  10.5   5.8
  5750   9.4  48.9  255   6  3  11.7   6.4 |  11.1  52.0  260   8  4  10.0   5.5
  5500  10.5  50.9  260   6  3  16.8   9.2 |  11.8  53.2  260   8  4  10.4   5.7
  5250  11.7  53.1  265   6  3  14.8   8.1 |  12.6  54.7  265   8  4  10.9   6.0
  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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