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 151229
SRGGJT

Soaring Forecast
National Weather Service Grand Junction, Colorado
0529 MST Wednesday, February 15, 2017

This forecast is for Wednesday, February 15, 2017:

If the trigger temperature of 51.0 F/10.6 C is reached...then
   Thermal Soaring Index....................... Fair
   Maximum rate of lift........................ 359 ft/min (1.8 m/s)
   Maximum height of thermals.................. 10424 ft MSL (5585 ft AGL)

Forecast maximum temperature................... 57.0 F/14.3 C
Time of trigger temperature.................... 1200 MST
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................. 8974 ft MSL (4135 ft AGL)
Thermal soaring outlook for Thursday 02/16..... Fair

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

Remarks...

Sunrise/Sunset.................... 07:05:04 / 17:50:31 MST
Total possible sunshine........... 10 hr 45 min 28 sec (645 min 28 sec)
Altitude of sun at 12:28:05 MST... 38.51 degrees

Upper air data from rawinsonde observation taken on 02/15/2017 at 0500 MST

Freezing level.................. 7292 ft MSL (2453 ft AGL)
Additional freezing levels...... 7706 ft MSL (2867 ft AGL)
                                 7889 ft MSL (3050 ft AGL)
Convective condensation level... 19860 ft MSL (15021 ft AGL)
Lifted condensation level....... 14140 ft MSL (9301 ft AGL)
Lifted index.................... +10.0
K index......................... -17.5

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  -61.8 -79.2   015   56   29   1.8   1.0  100.1 212.2    48.8      M    M
 45000  -59.6 -75.3   010   63   32  -2.3  -1.3   77.7 171.8    38.8      M    M
 40000  -61.2 -78.2   015   49   25   1.6   0.9   51.8 125.2    24.7      M    M
 38000  -61.5 -78.7   010   40   21   1.7   0.9   42.4 108.4    19.1      M    M
 36000  -59.0 -74.2   355   29   15   7.6   4.2   37.6  99.6    16.3      M    M
 34000  -54.5 -66.1   355   31   16   7.8   4.3   35.6  96.2    15.4      M    M
 32000  -48.9 -56.0   360   34   17   9.0   5.0   34.2  93.6    14.8      M    M
 30000  -43.6 -46.5   010   34   17   8.8   4.8   33.7  92.6    14.8      M    M
 29000  -40.9 -41.6   010   32   17   8.8   4.8   33.2  91.7    14.6      M    M
 28000  -38.3 -36.9   010   31   16   8.8   4.8   32.8  91.1    14.5      M    M
 27000  -35.7 -32.3   010   29   15   8.8   4.8   32.6  90.6    14.5      M    M
 26000  -33.0 -27.4   015   28   15   8.8   4.8   32.1  89.8    14.3      M    M
 25000  -30.3 -22.5   020   28   14   9.2   5.0   31.8  89.3    14.3      M    M
 24000  -27.6 -17.7   020   31   16   8.7   4.8   31.6  88.8    14.2      M    M
 23000  -25.0 -13.0   030   28   15   8.7   4.8   31.2  88.2    14.1      M    M
 22000  -22.4  -8.3   040   27   14   8.7   4.8   30.9  87.7    14.1      M    M
 21000  -19.7  -3.5   035   27   14   8.7   4.8   30.5  86.9    13.9      M    M
 20000  -17.1   1.2   030   28   14   8.7   4.8   30.2  86.3    13.8      M    M
 19500  -15.8   3.6   030   28   15   8.7   4.8   30.0  85.9    13.7      M    M
 19000  -14.5   5.9   030   29   15   8.8   4.8   29.8  85.6    13.6      M    M
 18500  -13.3   8.1   030   28   14   6.9   3.8   29.5  85.1    13.4      M    M
 18000  -12.5   9.5   035   26   13  -0.8  -0.5   28.7  83.6    12.8      M    M
 17500  -13.0   8.6   040   23   12   7.6   4.1   25.5  78.0    10.1      M    M
 17000  -11.9  10.6   045   21   11   7.5   4.1   25.1  77.2     9.8      M    M
 16500  -10.8  12.6   055   19   10   7.5   4.1   24.7  76.5     9.5      M    M
 16000   -9.7  14.5   060   18    9   8.0   4.4   24.4  75.9     9.3      M    M
 15500   -8.9  16.0   060   17    9   1.9   1.1   23.6  74.5     8.6      M    M
 15000   -8.4  16.9   055   17    9   6.0   3.3   22.6  72.7     7.8      M    M
 14500   -7.5  18.5   055   16    8   6.0   3.3   22.0  71.6     7.3      M    M
 14000   -6.6  20.1   055   16    8   6.0   3.3   21.4  70.5     6.7      M    M
 13500   -5.7  21.7   060   15    8   6.1   3.3   20.8  69.4     6.2      M    M
 13000   -4.8  23.4   060   14    7   4.4   2.4   20.1  68.2     5.6      M    M
 12500   -4.3  24.3   065   14    7   3.7   2.0   19.1  66.4     4.7      M    M
 12000   -3.8  25.2   070   13    7   3.7   2.0   18.2  64.7     3.8      M    M
 11500   -3.2  26.2   070   12    6   3.6   2.0   17.2  62.9     2.9      M    M
 11000   -2.7  27.1   070   10    5   3.2   1.8   16.2  61.1     2.0      M    M
 10500   -2.9  26.8   070    9    5  -4.8  -2.7   14.4  58.0     0.3      M    M
 10250   -3.3  26.1   070    8    4  -3.1  -1.7   13.3  56.0    -0.8    361  1.8
 10000   -3.3  26.1   075    9    5   2.6   1.4   12.5  54.5    -1.6    356  1.8
  9750   -2.9  26.8   085   10    5   6.1   3.4   12.1  53.8    -1.9    337  1.7
  9500   -2.6  27.3   090   11    6   5.2   2.9   11.8  53.2    -2.3    318  1.6
  9250   -2.2  28.0   090   13    6   5.5   3.0   11.5  52.6    -2.6    298  1.5
  9000   -1.8  28.8   095   14    7   5.4   3.0   11.1  52.0    -2.9    279  1.4
  8750   -1.4  29.5   100   12    6   5.5   3.0   10.8  51.4    -3.3    260  1.3
  8500   -1.0  30.2   105   11    6   5.2   2.8   10.4  50.8    -3.7    243  1.2
  8250   -0.7  30.7   115    9    5   6.9   3.8   10.1  50.2    -4.1    225  1.1
  8000   -0.1  31.8   125    8    4   6.1   3.4    9.9  49.9    -4.3    201  1.0
  7750    0.1  32.2   115    8    4  -2.1  -1.1    9.4  48.9    -4.8    187  0.9
  7500   -0.2  31.6   105    9    5  -2.5  -1.4    8.3  46.9    -5.8    187  1.0
  7250   -0.0  32.0   100   10    5   5.8   3.2    7.7  45.9    -6.4    175  0.9
  7000    0.6  33.1   090   11    6   8.3   4.6    7.5  45.6    -6.5    151  0.8
  6750    1.1  34.0   090   11    5   7.7   4.2    7.4  45.3    -6.7    126  0.6
  6500    1.7  35.1   085   10    5   7.8   4.3    7.2  45.0    -6.9    101  0.5
  6250    2.3  36.1   085   10    5   8.1   4.5    7.1  44.8    -7.1     76  0.4
  6000    2.8  37.0   080    9    5   4.5   2.5    6.9  44.4    -7.3     53  0.3
  5750    3.0  37.4   085   10    5   1.5   0.8    6.3  43.4    -7.9     41  0.2
  5500    3.1  37.6   095   11    6   2.3   1.3    5.7  42.3    -8.5     30  0.2
  5250    3.3  37.9   100   13    6   2.1   1.1    5.2  41.3    -9.1     18  0.1
  5000    3.1  37.6   105   13    7 -10.7  -5.9    4.3  39.7   -10.0     16  0.1

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

           02/15/2017 at 0800 MST          |       02/15/2017 at 1100 MST
                                           |
K index... -21.7  LI... +10.5              | K index... -21.7  LI... +9.9
CAPE... 0.0  CIN... M                      | CAPE... 0.0  CIN... -0.9
                                           |
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 -62.3 -80.1  020  48 25   1.1   0.6 | -62.3 -80.1  020  46 24   1.2   0.6
 45000 -60.6 -77.1  015  58 30   0.2   0.1 | -60.5 -76.9  020  61 32   1.3   0.7
 40000 -60.5 -76.9  025  44 23   0.0   0.0 | -58.7 -73.7  020  44 22   1.2   0.7
 38000 -58.9 -74.0  025  40 20   4.4   2.4 | -57.0 -70.6  025  40 20   3.9   2.1
 36000 -56.3 -69.3  015  36 18   4.4   2.4 | -54.4 -65.9  030  38 20   3.9   2.1
 34000 -53.2 -63.8  005  33 17   7.3   4.0 | -51.4 -60.5  030  36 19   6.6   3.6
 32000 -48.2 -54.8  360  32 17   7.3   4.0 | -47.5 -53.5  025  34 18   6.6   3.6
 30000 -43.7 -46.7  360  32 16   8.1   4.5 | -43.3 -45.9  020  32 17   7.7   4.2
 29000 -41.2 -42.2  005  32 16   8.1   4.5 | -41.0 -41.8  015  32 16   7.7   4.2
 28000 -38.8 -37.8  005  32 16   8.1   4.5 | -38.7 -37.7  015  31 16   7.7   4.2
 27000 -36.3 -33.3  010  32 16   8.7   4.8 | -36.3 -33.3  015  30 15   7.6   4.2
 26000 -33.7 -28.7  010  31 16   8.7   4.8 | -34.0 -29.2  015  29 15   7.7   4.2
 25000 -31.1 -24.0  015  30 15   8.7   4.8 | -31.8 -25.2  015  28 14   7.7   4.2
 24000 -28.5 -19.3  020  29 15   8.5   4.7 | -29.4 -20.9  015  27 14   8.6   4.7
 23000 -26.0 -14.8  020  27 14   8.5   4.7 | -26.8 -16.2  015  26 14   8.8   4.8
 22000 -23.4 -10.1  020  26 13   8.5   4.7 | -24.1 -11.4  015  26 13   8.8   4.8
 21000 -20.8  -5.4  020  25 13   9.3   5.1 | -21.4  -6.5  015  25 13   9.7   5.3
 20000 -18.1  -0.6  020  24 13   9.2   5.0 | -17.8  -0.0  020  24 12   9.6   5.3
 19500 -16.7   1.9  020  24 13   9.2   5.0 | -16.4   2.5  020  23 12   9.6   5.3
 19000 -15.3   4.5  020  24 13   9.4   5.2 | -14.9   5.2  020  23 12   9.1   5.0
 18500 -13.6   7.5  025  24 12   6.0   3.3 | -13.7   7.3  020  23 12   8.0   4.4
 18000 -12.7   9.1  025  23 12   6.1   3.3 | -12.5   9.5  025  23 12   8.2   4.5
 17500 -11.9  10.6  030  23 12   5.6   3.1 | -11.4  11.5  030  23 12   6.1   3.3
 17000 -11.0  12.2  030  22 11   5.6   3.1 | -10.5  13.1  035  23 12   6.0   3.3
 16500 -10.2  13.6  035  21 11   6.0   3.3 |  -9.6  14.7  035  23 12   6.1   3.3
 16000  -9.2  15.4  035  20 10   6.6   3.6 |  -8.7  16.3  040  22 11   6.1   3.4
 15500  -8.2  17.2  040  19 10   6.6   3.6 |  -7.8  18.0  040  20 10   6.1   3.4
 15000  -7.3  18.9  045  18  9   6.2   3.4 |  -6.9  19.6  040  18 10   6.0   3.3
 14500  -6.4  20.5  045  17  9   6.3   3.5 |  -6.0  21.2  040  16  8   6.1   3.4
 14000  -5.5  22.1  050  15  8   4.9   2.7 |  -5.1  22.8  040  14  7   5.4   2.9
 13500  -4.8  23.4  055  14  7   5.2   2.9 |  -4.3  24.3  040  12  6   5.6   3.1
 13000  -4.2  24.4  055  13  7   2.7   1.5 |  -3.6  25.5  040  11  5   3.4   1.9
 12500  -3.8  25.2  055  11  6   2.6   1.4 |  -3.1  26.4  040   9  4   3.4   1.9
 12000  -3.5  25.7  060   9  5   1.5   0.8 |  -2.8  27.0  035   7  3   1.4   0.8
 11500  -3.4  25.9  060   7  4   1.3   0.7 |  -2.6  27.3  025   5  2   1.2   0.6
 11000  -3.2  26.2  060   5  2   1.8   1.0 |  -2.5  27.5  010   3  1   1.4   0.8
 10500  -2.9  26.8  070   3  2   2.0   1.1 |  -2.3  27.9  340   1  1   1.5   0.8
 10250  -2.8  27.0  075   3  1   1.9   1.0 |  -2.2  28.0  305   1  1   1.6   0.9
 10000  -2.7  27.1  080   2  1   2.5   1.4 |  -2.1  28.2  290   1  1   2.4   1.3
  9750  -2.4  27.7  085   2  1   3.5   1.9 |  -1.9  28.6  275   1  1   3.2   1.8
  9500  -2.2  28.0  090   2  1   3.8   2.1 |  -1.6  29.1  255   1  1   3.4   1.8
  9250  -1.9  28.6  095   1  1   3.5   1.9 |  -1.4  29.5  245   2  1   3.3   1.8
  9000  -1.7  28.9  095   2  1   3.2   1.7 |  -1.2  29.8  235   1  1   3.3   1.8
  8750  -1.4  29.5  100   2  1   4.2   2.3 |  -0.9  30.4  225   1  1   3.8   2.1
  8500  -1.1  30.0  100   2  1   4.6   2.5 |  -0.7  30.7  215   2  1   4.0   2.2
  8250  -0.8  30.6  105   2  1   3.8   2.1 |  -0.4  31.3  205   2  1   3.7   2.0
  8000  -0.5  31.1  105   2  1   3.4   1.9 |  -0.1  31.8  195   2  1   3.5   1.9
  7750  -0.3  31.5  110   2  1   3.6   2.0 |   0.2  32.4  185   2  1   4.2   2.3
  7500  -0.0  32.0  110   2  1   2.9   1.6 |   0.5  32.9  175   2  1   4.2   2.3
  7250   0.1  32.2  115   2  1   2.1   1.2 |   0.7  33.3  170   2  1   3.4   1.9
  7000   0.3  32.5  120   3  1   2.2   1.2 |   1.0  33.8  165   2  1   3.4   1.9
  6750   0.4  32.7  120   3  2   2.4   1.3 |   1.2  34.2  160   2  1   3.9   2.2
  6500   0.6  33.1  120   3  2   1.5   0.8 |   1.6  34.9  155   2  1   6.5   3.6
  6250   0.6  33.1  115   4  2   0.7   0.4 |   2.1  35.8  150   1  1   7.8   4.3
  6000   0.7  33.3  110   4  2   0.7   0.4 |   2.7  36.9  145   1  1   7.4   4.1
  5750   0.6  33.1  105   5  2  -5.1  -2.8 |   3.3  37.9  130   1  1  12.8   7.0
  5500  -0.2  31.6  100   4  2 -13.4  -7.4 |   4.6  40.3  125   1  0  21.4  11.8
  5250     M     M    M   M  M     M     M |     M     M    M   M  M     M     M
  5000     M     M    M   M  M     M     M |     M     M    M   M  M     M     M

           02/15/2017 at 1400 MST          |       02/15/2017 at 1700 MST
                                           |
K index... -19.1  LI... +8.6               | K index... -21.9  LI... +7.5
CAPE... 0.0  CIN... -0.1                   | CAPE... 0.0  CIN... -0.4
                                           |
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 -62.7 -80.9  015  41 21   1.8   1.0 | -63.4 -82.1  015  45 23   3.2   1.8
 45000 -60.1 -76.2  020  51 26   1.4   0.8 | -58.6 -73.5  015  51 26   0.8   0.5
 40000 -57.8 -72.0  015  46 24   1.5   0.8 | -57.4 -71.3  015  45 23   0.9   0.5
 38000 -55.9 -68.6  015  44 23   3.9   2.1 | -55.6 -68.1  015  42 22   3.8   2.1
 36000 -53.6 -64.5  020  41 21   3.9   2.1 | -53.4 -64.1  015  39 20   3.8   2.1
 34000 -50.5 -58.9  020  39 20   7.1   3.9 | -50.5 -58.9  015  37 19   7.1   3.9
 32000 -46.3 -51.3  025  40 20   7.1   3.9 | -45.7 -50.3  015  37 19   7.1   3.9
 30000 -41.9 -43.4  025  38 20   7.8   4.3 | -41.2 -42.2  015  36 19   8.2   4.5
 29000 -39.5 -39.1  020  36 18   7.8   4.3 | -38.7 -37.7  015  34 18   8.2   4.5
 28000 -37.2 -35.0  020  33 17   7.8   4.3 | -36.3 -33.3  020  32 17   8.2   4.5
 27000 -34.9 -30.8  020  31 16   6.9   3.8 | -33.9 -29.0  020  30 16   7.6   4.2
 26000 -32.8 -27.0  015  29 15   7.0   3.8 | -31.6 -24.9  015  28 15   7.7   4.2
 25000 -30.7 -23.3  015  27 14   7.0   3.8 | -29.3 -20.7  015  26 13   7.7   4.2
 24000 -28.6 -19.5  010  25 13   7.5   4.1 | -27.0 -16.6  015  24 12   6.9   3.8
 23000 -26.3 -15.3  010  24 12   7.7   4.2 | -25.0 -13.0  010  23 12   6.8   3.7
 22000 -23.4 -10.1  005  22 11   7.8   4.3 | -22.9  -9.2  005  22 11   6.8   3.7
 21000 -20.9  -5.6  005  21 11   8.8   4.8 | -20.8  -5.4  360  21 11   8.2   4.5
 20000 -18.2  -0.8  005  19 10   8.8   4.8 | -18.4  -1.1  355  21 11   8.1   4.4
 19500 -16.9   1.6  010  19 10   8.8   4.8 | -17.2   1.0  355  21 11   8.1   4.4
 19000 -15.6   3.9  010  18  9   8.7   4.8 | -16.0   3.2  350  20 11   8.1   4.4
 18500 -14.3   6.3  015  18  9   8.3   4.5 | -14.2   6.4  350  19 10   7.9   4.3
 18000 -13.1   8.4  015  17  9   8.3   4.6 | -13.0   8.6  350  17  9   7.9   4.3
 17500 -11.9  10.6  020  16  8   7.4   4.1 | -11.8  10.8  350  16  8   7.5   4.1
 17000 -10.8  12.6  025  16  8   7.3   4.0 | -10.7  12.7  355  14  7   7.5   4.1
 16500  -9.7  14.5  030  15  8   7.0   3.9 |  -9.6  14.7  355  12  6   7.2   4.0
 16000  -8.7  16.3  035  15  8   6.6   3.6 |  -8.6  16.5  355  11  6   6.9   3.8
 15500  -7.7  18.1  040  14  7   6.6   3.6 |  -7.5  18.5  355  10  5   6.8   3.7
 15000  -6.8  19.8  040  13  7   5.7   3.1 |  -6.6  20.1  360   9  5   6.0   3.3
 14500  -5.9  21.4  040  12  6   5.8   3.2 |  -5.7  21.7  360   8  4   6.1   3.4
 14000  -5.1  22.8  040  11  6   5.2   2.8 |  -4.8  23.4  005   8  4   5.5   3.0
 13500  -4.3  24.3  035  10  5   5.3   2.9 |  -4.0  24.8  005   8  4   5.5   3.0
 13000  -3.6  25.5  030   9  5   4.3   2.3 |  -3.2  26.2  010   8  4   5.4   2.9
 12500  -3.0  26.6  020   8  4   4.3   2.3 |  -2.4  27.7  010   8  4   5.4   3.0
 12000  -2.4  27.7  015   8  4   2.6   1.5 |  -1.6  29.1  015   8  4   4.4   2.4
 11500  -2.1  28.2  005   6  3   2.4   1.3 |  -1.0  30.2  015   8  4   4.3   2.4
 11000  -1.8  28.8  355   6  3   2.3   1.3 |  -0.5  31.1  015   7  3   2.6   1.4
 10500  -1.4  29.5  345   5  2   2.6   1.4 |  -0.2  31.6  010   5  3   2.5   1.4
 10250  -1.3  29.7  340   4  2   1.6   0.9 |  -0.0  32.0  010   5  2   1.4   0.8
 10000  -1.2  29.8  335   4  2   1.6   0.9 |   0.0  32.0  010   4  2   1.0   0.6
  9750  -1.1  30.0  330   4  2   3.1   1.7 |   0.1  32.2  005   4  2   2.1   1.1
  9500  -0.8  30.6  325   3  2   3.2   1.7 |   0.2  32.4  360   3  1   1.9   1.1
  9250  -0.6  30.9  320   3  2   3.4   1.9 |   0.4  32.7  350   2  1   2.1   1.1
  9000  -0.3  31.5  315   3  1   3.8   2.1 |   0.5  32.9  350   2  1   2.7   1.5
  8750  -0.1  31.8  310   3  1   4.0   2.2 |   0.7  33.3  345   1  1   3.8   2.1
  8500   0.2  32.4  305   2  1   4.2   2.3 |   1.0  33.8  330   1  0   4.3   2.4
  8250   0.5  32.9  295   2  1   4.6   2.5 |   1.3  34.3  310   1  0   4.6   2.5
  8000   0.9  33.6  290   1  1   4.8   2.6 |   1.7  35.1  000   0  0   4.9   2.7
  7750   1.2  34.2  275   1  0   5.0   2.7 |   2.1  35.8  000   0  0   5.0   2.7
  7500   1.6  34.9  280   1  0   5.6   3.1 |   2.4  36.3  000   0  0   5.3   2.9
  7250   2.0  35.6  000   0  0   6.0   3.3 |   2.8  37.0  125   1  0   5.3   2.9
  7000   2.4  36.3  345   1  0   5.8   3.2 |   3.2  37.8  105   1  0   5.5   3.0
  6750   2.8  37.0  005   1  0   6.7   3.7 |   3.5  38.3  095   1  0   4.9   2.7
  6500   3.4  38.1  360   1  0   9.3   5.1 |   3.9  39.0  080   1  1   7.7   4.2
  6250   4.1  39.4  360   1  0  10.6   5.8 |   4.6  40.3  075   1  0  10.4   5.7
  6000   4.9  40.8  355   1  0   9.7   5.3 |   5.3  41.5  075   1  0   9.8   5.4
  5750   5.7  42.3  355   1  0  13.6   7.5 |   6.0  42.8  075   1  0   9.6   5.3
  5500   7.0  44.6  345   1  0  21.3  11.7 |   6.7  44.1  060   1  0   8.8   4.9
  5250     M     M    M   M  M     M     M |     M     M    M   M  M     M     M
  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.