Soaring Guidance
Issued by NWS Grand Junction, CO

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7
000
UXUS97 KGJT 271250
SRGGJT

Soaring Forecast
National Weather Service Grand Junction, Colorado
0650 MDT Wednesday, April 27, 2016

This forecast is for Wednesday, April 27, 2016:

If the trigger temperature of 50.2 F/10.1 C is reached...then
   Thermal Soaring Index....................... Fair
   Maximum rate of lift........................ 378 ft/min (1.9 m/s)
   Maximum height of thermals.................. 14559 ft MSL (9720 ft AGL)

Forecast maximum temperature................... 61.0 F/16.6 C
Time of trigger temperature.................... 1100 MDT
Time of overdevelopment........................ None
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................. 10658 ft MSL (5819 ft AGL)
Thermal soaring outlook for Thursday 04/28..... Good

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

Remarks...

Sunrise/Sunset.................... 06:20:16 / 20:02:52 MDT
Total possible sunshine........... 13 hr 42 min 37 sec (822 min 37 sec)
Altitude of sun at 13:11:44 MDT... 65.04 degrees

Upper air data from rawinsonde observation taken on 04/27/2016 at 0600 MDT

Freezing level.................. 7715 ft MSL (2876 ft AGL)
Convective condensation level... 9406 ft MSL (4567 ft AGL)
Lifted condensation level....... 11643 ft MSL (6804 ft AGL)
Lifted index.................... -1.2
K index......................... +18.0

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  -56.7 -70.1   255   21   11 -11.7  -6.4  108.2 226.7    52.3      M    M
 45000  -54.6 -66.3   280   24   12  -1.9  -1.1   86.8 188.3    42.9      M    M
 40000  -55.8 -68.4   295   40   20   0.9   0.5   61.5 142.7    29.5      M    M
 38000  -56.2 -69.2   290   47   24   3.3   1.8   52.0 125.6    23.9      M    M
 36000  -55.5 -67.9   285   52   27  -0.7  -0.4   44.4 111.9    19.4      M    M
 34000  -55.5 -67.9   305   66   34   7.6   4.2   34.9  94.9    13.3      M    M
 32000  -50.2 -58.4   305   70   36   9.2   5.1   34.1  93.4    13.1      M    M
 30000  -45.1 -49.2   310   62   32   6.6   3.6   33.2  91.7    12.7      M    M
 29000  -43.2 -45.8   305   59   30   6.0   3.3   31.8  89.2    11.8      M    M
 28000  -40.7 -41.3   300   57   29   8.7   4.8   31.1  88.0    11.5      M    M
 27000  -38.8 -37.8   295   55   28   3.6   2.0   29.9  85.8    10.7      M    M
 26000  -36.9 -34.4   290   53   27   6.0   3.3   28.5  83.2     9.7      M    M
 25000  -35.3 -31.5   295   43   22   3.2   1.7   26.8  80.2     8.5      M    M
 24000  -33.6 -28.5   300   33   17   8.2   4.5   25.3  77.5     7.4      M    M
 23000  -31.1 -24.0   295   30   16   8.3   4.5   24.7  76.5     7.0      M    M
 22000  -28.6 -19.5   290   27   14   8.3   4.5   24.2  75.6     6.7      M    M
 21000  -26.1 -15.0   290   28   15   8.2   4.5   23.6  74.6     6.3      M    M
 20000  -24.0 -11.2   295   30   15   5.9   3.3   22.7  72.8     5.5      M    M
 19500  -23.3  -9.9   295   28   15   4.4   2.4   21.8  71.3     4.8      M    M
 19000  -22.3  -8.1   300   25   13   6.3   3.5   20.5  68.9     3.7      M    M
 18500  -21.1  -6.0   300   23   12   6.4   3.5   20.2  68.3     3.4      M    M
 18000  -20.3  -4.5   305   21   11   6.3   3.4   19.5  67.2     2.8      M    M
 17500  -19.5  -3.1   300   23   12   4.7   2.6   18.7  65.7     2.1      M    M
 17000  -18.8  -1.8   295   25   13   4.6   2.5   17.9  64.2     1.4      M    M
 16500  -17.9  -0.2   305   23   12   8.8   4.8   17.3  63.1     0.8      M    M
 16000  -16.5   2.3   315   23   12   9.4   5.1   17.2  63.0     0.8      M    M
 15500  -15.1   4.8   310   22   11   9.3   5.1   17.2  62.9     0.7      M    M
 15000  -13.8   7.2   310   21   11   8.4   4.6   17.0  62.5     0.5      M    M
 14500  -13.2   8.2   305   20   10   1.5   0.8   16.1  61.0    -0.3    772  3.9
 14000  -12.9   8.8   300   19   10   4.8   2.6   14.8  58.7    -1.5    750  3.8
 13500  -11.7  10.9   305   17    9   8.6   4.7   14.6  58.2    -1.8    699  3.5
 13000  -10.4  13.3   310   16    8   8.7   4.8   14.4  57.9    -1.9    645  3.3
 12500   -9.1  15.6   315   15    8   8.7   4.8   14.3  57.7    -2.1    592  3.0
 12000   -7.8  18.0   320   14    7   8.8   4.8   14.1  57.5    -2.2    538  2.7
 11500   -6.5  20.3   325   13    7   8.8   4.8   14.0  57.1    -2.4    484  2.5
 11000   -5.2  22.6   335   13    7   9.8   5.4   13.8  56.8    -2.6    431  2.2
 10500   -4.6  23.7   315   11    6  -1.7  -1.0   13.0  55.3    -3.5    397  2.0
 10250   -4.7  23.5   305   11    6   1.0   0.6   12.1  53.8    -4.3    392  2.0
 10000   -4.4  24.1   295   11    6   6.6   3.6   11.6  53.0    -4.8    377  1.9
  9750   -3.8  25.2   300   11    6   8.2   4.5   11.5  52.7    -4.9    352  1.8
  9500   -3.3  26.1   300   10    5   7.2   3.9   11.3  52.4    -5.1    328  1.7
  9250   -2.7  27.1   300   10    5   7.3   4.0   11.1  52.0    -5.3    304  1.5
  9000   -2.2  28.0   300    9    5   8.0   4.4   11.0  51.7    -5.5    281  1.4
  8750   -1.8  28.8   290    9    4   0.6   0.3   10.7  51.2    -5.8    260  1.3
  8500   -1.9  28.6   280    8    4   3.4   1.9    9.8  49.6    -6.7    257  1.3
  8250   -1.2  29.8   270    9    4   9.2   5.0    9.7  49.5    -6.8    230  1.2
  8000   -0.7  30.7   260    9    5   6.1   3.3    9.5  49.1    -7.1    207  1.1
  7750   -0.2  31.6   260    8    4   8.0   4.4    9.3  48.7    -7.3    184  0.9
  7500    0.4  32.7   260    7    3   7.5   4.1    9.1  48.4    -7.5    160  0.8
  7250    0.9  33.6   255    6    3   7.7   4.2    9.0  48.2    -7.7    136  0.7
  7000    1.5  34.7   255    4    2   7.7   4.2    8.8  47.9    -7.9    112  0.6
  6750    2.0  35.6   250    3    1   7.7   4.2    8.7  47.6    -8.1     89  0.4
  6500    2.6  36.7   230    1    1   7.8   4.3    8.5  47.3    -8.3     64  0.3
  6250    3.2  37.8   120    1    0   7.9   4.3    8.4  47.1    -8.4     39  0.2
  6000    3.8  38.8   095    3    1   7.9   4.4    8.2  46.8    -8.6     14  0.1
  5750    4.4  39.9   090    3    2   7.8   4.3    8.1  46.6    -8.7      M    M
  5500    4.9  40.8   085    3    1   6.5   3.5    7.9  46.2    -9.0      M    M
  5250    5.2  41.4   080    3    1   3.4   1.9    7.6  45.6    -9.4      M    M
  5000    5.2  41.4   070    3    2  -3.1  -1.7    6.9  44.4   -10.2      M    M

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

           04/27/2016 at 0900 MDT          |       04/27/2016 at 1200 MDT
                                           |
K index... +17.1  LI... +275.2             | K index... +17.5  LI... +274.0
CAPE... 0.0  CIN... -0.5                   | CAPE... +20.0  CIN... -8.4
                                           |
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 -56.3 -69.3  265  23 12  -0.2  -0.1 | -57.2 -71.0  255  19 10   0.3   0.2
 45000 -56.6 -69.9  280  30 16  -0.2  -0.1 | -56.7 -70.1  270  30 15   0.4   0.2
 40000 -56.7 -70.1  290  44 22  -0.1  -0.0 | -57.8 -72.0  280  47 24  -0.8  -0.4
 38000 -56.4 -69.5  290  47 24   1.2   0.7 | -57.4 -71.3  280  52 27   2.8   1.5
 36000 -55.7 -68.3  295  48 25   1.2   0.7 | -55.8 -68.4  280  52 27   2.7   1.5
 34000 -54.9 -66.8  295  49 25   5.7   3.1 | -53.9 -65.0  280  52 27   6.5   3.6
 32000 -50.0 -58.0  300  49 25   8.1   4.4 | -49.4 -56.9  280  46 24   7.5   4.1
 30000 -45.2 -49.4  300  49 25   8.3   4.5 | -44.9 -48.8  280  40 20   8.3   4.6
 29000 -42.7 -44.9  300  49 25   8.3   4.5 | -42.4 -44.3  285  39 20   8.3   4.6
 28000 -40.2 -40.4  300  50 26   8.3   4.5 | -39.9 -39.8  285  38 19   8.4   4.6
 27000 -37.7 -35.9  300  51 26   8.3   4.6 | -36.8 -34.2  285  36 19   8.3   4.5
 26000 -34.9 -30.8  300  49 25   7.5   4.1 | -34.4 -29.9  290  36 18   8.0   4.4
 25000 -32.6 -26.7  305  47 24   7.5   4.1 | -32.0 -25.6  295  35 18   8.0   4.4
 24000 -30.4 -22.7  305  44 23   7.7   4.2 | -29.6 -21.3  300  35 18   8.3   4.5
 23000 -28.6 -19.5  305  40 21   5.2   2.9 | -27.7 -17.9  305  32 16   5.8   3.2
 22000 -27.1 -16.8  305  34 18   5.2   2.9 | -25.9 -14.6  305  28 14   5.8   3.2
 21000 -25.5 -13.9  305  29 15   5.6   3.1 | -24.2 -11.6  310  24 12   5.8   3.2
 20000 -23.4 -10.1  305  27 14   7.2   4.0 | -22.4  -8.3  305  23 12   5.9   3.3
 19500 -22.3  -8.1  305  26 13   7.2   4.0 | -21.5  -6.7  305  22 12   5.9   3.3
 19000 -21.3  -6.3  305  24 13   7.2   4.0 | -20.7  -5.3  300  22 11   5.9   3.3
 18500 -20.2  -4.4  305  23 12   7.3   4.0 | -19.8  -3.6  300  22 11   6.0   3.3
 18000 -19.2  -2.6  300  23 12   6.2   3.4 | -18.9  -2.0  295  21 11   6.3   3.5
 17500 -18.3  -0.9  300  22 11   6.4   3.5 | -17.9  -0.2  295  21 11   6.4   3.5
 17000 -17.4   0.7  300  21 11   6.0   3.3 | -17.0   1.4  295  21 11   6.6   3.6
 16500 -16.5   2.3  300  20 10   5.8   3.2 | -16.0   3.2  290  21 11   6.7   3.7
 16000 -15.7   3.7  300  19 10   6.0   3.3 | -15.1   4.8  290  21 11   6.7   3.7
 15500 -14.8   5.4  300  18  9   6.4   3.5 | -14.1   6.6  290  20 10   6.6   3.6
 15000 -13.9   7.0  300  17  9   6.4   3.5 | -13.2   8.2  290  19 10   6.7   3.7
 14500 -12.8   9.0  300  16  8   8.4   4.6 | -12.2  10.0  290  19 10   7.2   4.0
 14000 -11.6  11.1  300  16  8   8.3   4.5 | -11.1  12.0  290  18  9   7.2   3.9
 13500 -10.4  13.3  300  15  8   8.3   4.5 | -10.1  13.8  290  17  9   7.1   3.9
 13000  -8.5  16.7  300  15  8   7.8   4.3 |  -8.5  16.7  295  16  8   7.2   3.9
 12500  -7.6  18.3  300  15  8   6.2   3.4 |  -7.5  18.5  295  15  8   7.2   4.0
 12000  -6.7  19.9  300  15  8   5.9   3.2 |  -6.4  20.5  295  15  8   7.2   4.0
 11500  -6.0  21.2  300  13  7   4.2   2.3 |  -5.3  22.5  295  14  7   7.2   4.0
 11000  -5.4  22.3  295  12  6   4.5   2.5 |  -4.3  24.3  295  12  6   7.1   3.9
 10500  -4.7  23.5  295  10  5   5.6   3.1 |  -3.3  26.1  290  11  6   6.7   3.7
 10250  -4.3  24.3  295  10  5   5.2   2.8 |  -2.8  27.0  285  10  5   6.3   3.5
 10000  -3.9  25.0  295  10  5   5.6   3.1 |  -2.4  27.7  280  10  5   5.7   3.1
  9750  -3.5  25.7  290   9  5   6.8   3.7 |  -2.0  28.4  280   9  5   5.7   3.2
  9500  -3.0  26.6  285   9  4   7.0   3.8 |  -1.6  29.1  275   8  4   6.1   3.3
  9250  -2.5  27.5  280   8  4   7.0   3.8 |  -1.1  30.0  275   7  4   5.1   2.8
  9000  -2.0  28.4  275   8  4   5.6   3.1 |  -0.8  30.6  265   6  3   5.5   3.0
  8750  -1.6  29.1  270   7  3   5.2   2.9 |  -0.3  31.5  265   6  3   6.9   3.8
  8500  -1.2  29.8  260   6  3   5.9   3.2 |   0.1  32.2  260   5  3   6.4   3.5
  8250  -0.8  30.6  250   5  3   6.2   3.4 |   0.6  33.1  255   4  2   7.3   4.0
  8000  -0.3  31.5  240   4  2   6.7   3.6 |   1.2  34.2  250   4  2   9.1   5.0
  7750   0.1  32.2  230   4  2   5.8   3.2 |   1.9  35.4  250   4  2   9.4   5.1
  7500   0.5  32.9  220   4  2   5.0   2.7 |   2.5  36.5  245   4  2   8.7   4.8
  7250   0.9  33.6  210   4  2   6.3   3.5 |   3.2  37.8  245   3  2   9.8   5.4
  7000   1.5  34.7  200   4  2   7.7   4.2 |   3.9  39.0  245   4  2  10.7   5.9
  6750   2.0  35.6  195   4  2   7.0   3.8 |   4.7  40.5  245   4  2   9.9   5.4
  6500   2.5  36.5  185   4  2   7.8   4.3 |   5.4  41.7  245   4  2  10.1   5.5
  6250   3.2  37.8  185   4  2  10.7   5.9 |   6.2  43.2  245   4  2  11.2   6.1
  6000   4.0  39.2  180   4  2  11.6   6.4 |   7.1  44.8  245   4  2  11.8   6.5
  5750   4.9  40.8  180   4  2  10.5   5.8 |   8.0  46.4  245   4  2  11.0   6.0
  5500   5.6  42.1  180   4  2   9.9   5.5 |   8.8  47.8  245   4  2  13.7   7.5
  5250   6.3  43.3  180   4  2  10.0   5.5 |  10.0  50.0  250   4  2  19.5  10.7
  5000     M     M    M   M  M     M     M |     M     M    M   M  M     M     M

           04/27/2016 at 1500 MDT          |       04/27/2016 at 1800 MDT
                                           |
K index... +12.3  LI... +273.4             | K index... +12.4  LI... +274.3
CAPE... +40.8  CIN... -24.6                | CAPE... 0.0  CIN... M
                                           |
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 -57.9 -72.2  245  18  9   0.9   0.5 | -57.6 -71.7  245  22 11   1.1   0.6
 45000 -56.5 -69.7  255  23 12   1.1   0.6 | -56.0 -68.8  250  22 11   1.2   0.7
 40000 -57.3 -71.1  265  53 27  -0.6  -0.3 | -56.7 -70.1  260  53 28  -0.5  -0.3
 38000 -56.8 -70.2  265  58 30   2.6   1.4 | -56.3 -69.3  260  58 30   2.2   1.2
 36000 -55.2 -67.4  265  54 28   2.6   1.4 | -55.0 -67.0  260  52 27   2.2   1.2
 34000 -53.5 -64.3  265  51 26   6.6   3.6 | -53.5 -64.3  260  45 23   5.5   3.0
 32000 -49.1 -56.4  265  46 24   7.4   4.0 | -49.8 -57.6  255  40 20   6.2   3.4
 30000 -44.6 -48.3  265  42 22   8.1   4.5 | -46.0 -50.8  255  34 18   8.7   4.8
 29000 -42.2 -44.0  265  39 20   8.0   4.4 | -43.4 -46.1  255  33 17   8.8   4.8
 28000 -39.2 -38.6  265  35 18   8.0   4.4 | -40.7 -41.3  255  32 16   8.8   4.8
 27000 -36.8 -34.2  265  32 16   7.9   4.3 | -37.5 -35.5  255  31 16   8.8   4.8
 26000 -34.6 -30.3  270  29 15   7.6   4.2 | -34.8 -30.6  255  29 15   8.7   4.8
 25000 -32.3 -26.1  270  27 14   7.7   4.2 | -32.2 -26.0  255  28 14   8.8   4.8
 24000 -30.0 -22.0  275  25 13   7.7   4.2 | -29.6 -21.3  255  26 14   8.8   4.8
 23000 -27.7 -17.9  280  24 12   7.5   4.1 | -27.5 -17.5  260  25 13   6.5   3.6
 22000 -25.4 -13.7  280  22 11   7.6   4.1 | -25.6 -14.1  260  23 12   6.6   3.6
 21000 -23.2  -9.8  280  20 10   6.9   3.8 | -23.6 -10.5  260  20 11   6.8   3.7
 20000 -21.5  -6.7  280  18 10   5.5   3.0 | -21.5  -6.7  265  20 10   7.1   3.9
 19500 -20.6  -5.1  280  18  9   5.5   3.0 | -20.5  -4.9  265  19 10   7.1   3.9
 19000 -19.8  -3.6  280  17  9   5.5   3.0 | -19.4  -2.9  270  19 10   7.1   3.9
 18500 -19.0  -2.2  280  16  8   5.6   3.1 | -18.3  -0.9  270  19 10   7.2   3.9
 18000 -18.1  -0.6  280  16  8   6.3   3.5 | -17.3   0.9  275  19 10   7.5   4.1
 17500 -17.2   1.0  280  15  8   6.3   3.5 | -16.2   2.8  275  19 10   7.6   4.2
 17000 -16.3   2.7  275  15  8   5.9   3.2 | -15.1   4.8  275  19 10   7.0   3.8
 16500 -15.4   4.3  275  15  8   5.9   3.2 | -14.1   6.6  270  18  9   6.9   3.8
 16000 -14.6   5.7  275  15  8   6.1   3.3 | -13.1   8.4  270  17  9   6.8   3.7
 15500 -13.6   7.5  275  15  8   6.4   3.5 | -12.1  10.2  265  15  8   6.6   3.6
 15000 -12.7   9.1  275  15  8   6.5   3.6 | -11.1  12.0  260  14  7   6.6   3.6
 14500 -11.6  11.1  275  15  8   7.7   4.3 | -10.0  14.0  260  13  7   7.9   4.3
 14000 -10.5  13.1  280  14  7   7.6   4.2 |  -8.9  16.0  255  12  6   7.8   4.3
 13500  -8.7  16.3  280  14  7   8.4   4.6 |  -7.7  18.1  255  11  6   8.0   4.4
 13000  -7.5  18.5  280  14  7   8.5   4.6 |  -6.0  21.2  255  10  5   7.9   4.3
 12500  -6.3  20.7  280  13  7   8.5   4.7 |  -4.8  23.4  260   8  4   7.8   4.3
 12000  -5.0  23.0  280  13  7   8.5   4.7 |  -3.7  25.3  260   7  4   7.8   4.3
 11500  -3.8  25.2  280  12  6   8.4   4.6 |  -2.5  27.5  265   6  3   7.8   4.3
 11000  -2.5  27.5  285  12  6   8.4   4.6 |  -1.3  29.7  275   5  3   7.7   4.2
 10500  -1.3  29.7  285  11  6   8.0   4.4 |  -0.2  31.6  280   4  2   7.2   3.9
 10250  -0.7  30.7  285  10  5   8.7   4.8 |   0.4  32.7  285   4  2   8.3   4.6
 10000  -0.1  31.8  285  10  5   8.7   4.8 |   1.0  33.8  285   3  2   9.0   4.9
  9750   0.5  32.9  285   9  5   7.7   4.2 |   1.7  35.1  290   3  1   7.9   4.4
  9500   1.1  34.0  285   9  4   7.8   4.3 |   2.2  36.0  290   2  1   7.8   4.3
  9250   1.7  35.1  285   8  4   7.2   3.9 |   2.8  37.0  300   2  1   7.9   4.3
  9000   2.2  36.0  290   7  4   6.8   3.7 |   3.4  38.1  310   1  1   7.5   4.1
  8750   2.7  36.9  290   6  3   7.3   4.0 |   3.9  39.0  335   1  0   7.1   3.9
  8500   3.2  37.8  295   5  3   7.0   3.8 |   4.4  39.9  035   1  0   7.1   3.9
  8250   3.7  38.7  295   4  2   7.7   4.2 |   5.0  41.0  065   1  1   7.4   4.1
  8000   4.3  39.7  300   4  2   9.2   5.0 |   5.5  41.9  085   2  1   8.6   4.7
  7750   4.9  40.8  300   3  2   9.3   5.1 |   6.1  43.0  090   2  1   8.7   4.8
  7500   5.6  42.1  300   3  2   8.9   4.9 |   6.7  44.1  090   2  1   8.1   4.5
  7250   6.2  43.2  300   3  1   9.4   5.2 |   7.3  45.1  095   2  1   9.1   5.0
  7000   6.9  44.4  300   3  1   9.9   5.4 |   8.0  46.4  095   2  1  10.4   5.7
  6750   7.7  45.9  300   3  1   9.9   5.4 |   8.8  47.8  095   2  1  10.2   5.6
  6500   8.4  47.1  300   2  1   9.9   5.4 |   9.5  49.1  100   2  1   9.9   5.4
  6250   9.2  48.6  295   2  1  11.0   6.1 |  10.3  50.5  105   2  1  10.1   5.5
  6000  10.0  50.0  295   2  1  11.9   6.5 |  11.0  51.8  105   2  1  10.2   5.6
  5750  10.9  51.6  295   2  1  10.9   6.0 |  11.8  53.2  105   2  1  10.0   5.5
  5500  11.7  53.1  295   2  1  13.2   7.2 |  12.5  54.5  110   2  1  10.0   5.5
  5250  12.9  55.2  295   2  1  19.2  10.5 |  13.2  55.8  105   2  1  10.2   5.6
  5000     M     M    M   M  M     M     M |     M     M    M   M  M     M     M
________________________________________________________________________________

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

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

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

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

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

DEFINITIONS:

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

042613



USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.