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 8 9 10 11 12 13 14 15 16
000
UXUS97 KGJT 261238
SRGGJT

Soaring Forecast
National Weather Service Grand Junction, Colorado
0638 MDT Sunday, April 26, 2015

This forecast is for Sunday, April 26, 2015:

If the trigger temperature of 53.3 F/11.9 C is reached...then
   Thermal Soaring Index....................... Poor
   Maximum rate of lift........................ 6 ft/min (0.0 m/s)
   Maximum height of thermals.................. 10383 ft MSL (5544 ft AGL)

Forecast maximum temperature................... 56.0 F/13.8 C
Time of trigger temperature.................... 1330 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................. 7194 ft MSL (2355 ft AGL)
Thermal soaring outlook for Monday 04/27....... Poor

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

Remarks...

Sunrise/Sunset.................... 06:22:31 / 20:01:09 MDT
Total possible sunshine........... 13 hr 38 min 38 sec (818 min 38 sec)
Altitude of sun at 13:12:00 MDT... 64.48 degrees

Upper air data from rawinsonde observation taken on 04/26/2015 at 0600 MDT

Freezing level.................. 8809 ft MSL (3970 ft AGL)
Convective condensation level... 9027 ft MSL (4188 ft AGL)
Lifted condensation level....... 9599 ft MSL (4760 ft AGL)
Lifted index.................... +0.3
K index......................... +24.0

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  -55.9 -68.6   290   25   13   3.2   1.7  108.9 228.0    54.4      M    M
 45000  -54.8 -66.6   265   24   12   0.4   0.2   85.9 186.6    44.1      M    M
 40000  -52.6 -62.7   250   10    5  -1.0  -0.5   66.2 151.1    34.4      M    M
 38000  -53.3 -63.9   230   16    8   2.6   1.4   56.2 133.1    28.6      M    M
 36000  -55.7 -68.3   200   21   11  -7.7  -4.2   44.0 111.1    21.0      M    M
 34000  -56.1 -69.0   165   20   10   6.4   3.5   33.8  92.9    14.5      M    M
 32000  -54.6 -66.3   165   29   15   9.9   5.5   27.7  81.9    10.5      M    M
 30000  -48.9 -56.0   165   32   16   9.1   5.0   27.6  81.7    10.7      M    M
 29000  -46.1 -51.0   165   32   16   9.1   5.0   27.3  81.2    10.6      M    M
 28000  -43.3 -45.9   165   32   16   9.9   5.4   27.2  80.9    10.6      M    M
 27000  -40.5 -40.9   165   32   16   9.2   5.0   27.0  80.6    10.6      M    M
 26000  -37.7 -35.9   165   32   16   9.2   5.0   26.8  80.2    10.5      M    M
 25000  -35.0 -31.0   165   32   16   9.2   5.0   26.7  80.0    10.6      M    M
 24000  -32.3 -26.1   165   31   16   9.0   5.0   26.4  79.5    10.5      M    M
 23000  -29.7 -21.5   165   31   16   8.5   4.7   26.0  78.8    10.3      M    M
 22000  -27.2 -17.0   170   30   15   8.1   4.4   25.4  77.7     9.8      M    M
 21000  -24.8 -12.6   175   29   15   8.1   4.4   24.8  76.6     9.4      M    M
 20000  -22.4  -8.3   180   28   14   8.1   4.5   24.3  75.8     9.1      M    M
 19500  -21.2  -6.2   180   28   15   8.1   4.5   24.0  75.3     8.9      M    M
 19000  -19.5  -3.1   185   29   15   8.1   4.4   23.6  74.5     8.6      M    M
 18500  -18.3  -0.9   185   27   14   6.9   3.8   23.3  73.9     8.3      M    M
 18000  -17.3   0.9   185   28   14   7.2   4.0   22.7  72.8     7.8      M    M
 17500  -16.3   2.7   185   29   15   7.0   3.9   22.2  71.9     7.4      M    M
 17000  -15.2   4.6   180   29   15   7.0   3.8   21.7  71.1     7.1      M    M
 16500  -14.2   6.4   180   30   16   7.0   3.8   21.3  70.3     6.7      M    M
 16000  -13.2   8.2   180   31   16   6.6   3.6   20.8  69.4     6.3      M    M
 15500  -12.2  10.0   180   28   14   6.6   3.6   20.2  68.4     5.8      M    M
 15000  -11.3  11.7   175   26   13   6.7   3.6   19.7  67.5     5.3      M    M
 14500  -10.3  13.5   175   23   12   6.7   3.7   19.2  66.6     4.9      M    M
 14000   -9.3  15.3   170   21   11   6.7   3.7   18.8  65.8     4.5      M    M
 13500   -8.4  16.9   160   19   10   6.7   3.7   18.2  64.8     4.0      M    M
 13000   -7.4  18.7   150   18    9   6.7   3.7   17.7  63.9     3.5      M    M
 12500   -6.4  20.5   165   17    9   6.6   3.6   17.2  63.0     3.0      M    M
 12000   -5.6  21.9   175   17    9   4.9   2.7   16.5  61.8     2.4      M    M
 11500   -4.9  23.2   185   16    8   5.0   2.8   15.8  60.4     1.6      M    M
 11000   -4.1  24.6   195   16    8   5.0   2.8   15.0  59.0     0.9      M    M
 10500   -3.4  25.9   200   10    5   5.0   2.8   14.3  57.7     0.2      M    M
 10250   -3.1  26.4   210    8    4   5.2   2.8   13.9  57.0    -0.2    397  2.0
 10000   -2.7  27.1   225    5    3   4.6   2.5   13.5  56.3    -0.5    379  1.9
  9750   -2.3  27.9   220    6    3   6.6   3.6   13.1  55.6    -0.9    360  1.8
  9500   -1.7  28.9   215    6    3   8.6   4.7   13.0  55.4    -1.0    335  1.7
  9250   -1.1  30.0   215    5    3   8.0   4.4   12.9  55.2    -1.2    310  1.6
  9000   -0.5  31.1   210    5    3   8.1   4.5   12.8  55.0    -1.3    284  1.4
  8750    0.1  32.2   195    6    3   8.1   4.4   12.6  54.7    -1.5    259  1.3
  8500    0.7  33.3   185    6    3   8.1   4.4   12.5  54.5    -1.6    234  1.2
  8250    1.3  34.3   175    8    4   8.2   4.5   12.4  54.3    -1.7    209  1.1
  8000    1.9  35.4   170    9    5   7.6   4.2   12.2  54.0    -1.9    183  0.9
  7750    2.3  36.1   170    7    4   5.8   3.2   12.0  53.6    -2.1    161  0.8
  7500    2.7  36.9   175    5    3   4.5   2.4   11.6  52.9    -2.5    144  0.7
  7250    3.0  37.4   180    3    2   6.5   3.5   11.3  52.3    -2.9    127  0.6
  7000    3.6  38.5   210    1    1   8.1   4.5   11.1  52.0    -3.1    102  0.5
  6750    4.1  39.4   300    1    1   7.6   4.2   11.0  51.7    -3.3     78  0.4
  6500    4.7  40.5   330    2    1   8.0   4.4   10.8  51.5    -3.4     53  0.3
  6250    5.2  41.4   335    4    2   5.7   3.1   10.6  51.2    -3.6     30  0.2
  6000    5.6  42.1   340    6    3   4.2   2.3   10.2  50.4    -4.0     12  0.1
  5750    5.9  42.6   340    5    3   3.3   1.8    9.8  49.7    -4.4      M    M
  5500    6.1  43.0   335    5    2   1.7   0.9    9.2  48.6    -5.1      M    M
  5250    6.1  43.0   330    4    2   1.4   0.8    8.6  47.5    -5.7      M    M
  5000    6.2  43.2   320    4    2   2.9   1.6    8.0  46.4    -6.4      M    M

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

           04/26/2015 at 0900 MDT          |       04/26/2015 at 1200 MDT
                                           |
K index... +22.2  LI... +273.9             | K index... +21.9  LI... +273.0
CAPE... 0.0  CIN... M                      | CAPE... +23.6  CIN... -0.3
                                           |
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 -54.4 -65.9  290  17  9   0.8   0.4 | -54.5 -66.1  310  18  9   1.1   0.6
 45000 -53.3 -63.9  290  17  9   0.8   0.4 | -52.8 -63.0  315  19 10   1.0   0.5
 40000 -52.1 -61.8  275  12  6   0.8   0.4 | -52.3 -62.1  315  10  5   0.3   0.2
 38000 -52.2 -62.0  250   9  5  -2.1  -1.1 | -52.5 -62.5  310   4  2  -1.3  -0.7
 36000 -53.5 -64.3  190  10  5  -2.1  -1.2 | -53.3 -63.9  150   8  4  -1.4  -0.7
 34000 -54.7 -66.5  165  18  9  -1.3  -0.7 | -54.1 -65.4  150  21 11  -0.4  -0.2
 32000 -52.1 -61.8  150  23 12   5.0   2.7 | -51.6 -60.9  150  24 12   4.6   2.5
 30000 -49.1 -56.4  145  29 15   6.4   3.5 | -48.2 -54.8  150  26 14   9.4   5.1
 29000 -46.5 -51.7  145  27 14   9.0   5.0 | -45.5 -49.9  150  25 13   9.2   5.0
 28000 -43.1 -45.6  150  26 13   9.0   5.0 | -42.7 -44.9  155  23 12   9.2   5.0
 27000 -40.4 -40.7  155  24 13   9.1   5.0 | -40.0 -40.0  155  21 11   9.2   5.1
 26000 -37.8 -36.0  155  22 11   8.4   4.6 | -37.3 -35.1  150  20 10   8.9   4.9
 25000 -35.3 -31.5  155  19 10   8.5   4.6 | -34.6 -30.3  150  19 10   8.9   4.9
 24000 -32.8 -27.0  160  16  8   8.5   4.6 | -32.0 -25.6  145  18  9   8.9   4.9
 23000 -30.2 -22.4  165  14  7   8.7   4.7 | -29.4 -20.9  145  17  8   8.4   4.6
 22000 -27.6 -17.7  165  13  7   8.7   4.8 | -26.9 -16.4  145  15  8   8.4   4.6
 21000 -25.0 -13.0  170  11  6   8.6   4.7 | -24.4 -11.9  145  14  7   8.3   4.6
 20000 -22.8  -9.0  175  11  5   7.6   4.1 | -22.2  -8.0  140  13  7   7.4   4.0
 19500 -21.6  -6.9  175  10  5   7.6   4.2 | -21.1  -6.0  140  12  6   7.4   4.1
 19000 -20.5  -4.9  175  10  5   7.6   4.2 | -20.0  -4.0  135  12  6   7.4   4.1
 18500 -19.4  -2.9  175  10  5   7.6   4.2 | -18.9  -2.0  135  11  6   7.5   4.1
 18000 -18.3  -0.9  175   9  5   7.3   4.0 | -17.9  -0.2  130  11  6   7.2   3.9
 17500 -17.2   1.0  175   9  5   7.4   4.0 | -16.8   1.8  130  11  5   7.2   4.0
 17000 -16.1   3.0  170   8  4   7.4   4.0 | -15.7   3.7  130  10  5   7.2   4.0
 16500 -15.0   5.0  170   8  4   7.3   4.0 | -14.7   5.5  125  10  5   7.2   4.0
 16000 -14.0   6.8  165   7  4   7.3   4.0 | -13.6   7.5  125   9  5   7.2   4.0
 15500 -12.9   8.8  165   7  4   7.4   4.0 | -12.5   9.5  125   9  5   7.2   3.9
 15000 -11.8  10.8  160   7  3   7.4   4.0 | -11.5  11.3  120   9  4   7.2   4.0
 14500 -10.7  12.7  155   6  3   7.7   4.2 |  -9.9  14.2  120   8  4   7.0   3.8
 14000  -9.6  14.7  155   6  3   7.8   4.3 |  -8.9  16.0  115   7  4   6.9   3.8
 13500  -8.0  17.6  150   7  3   6.9   3.8 |  -7.9  17.8  115   6  3   6.6   3.6
 13000  -7.0  19.4  150   7  4   6.9   3.8 |  -7.0  19.4  110   6  3   6.6   3.6
 12500  -6.0  21.2  150   7  4   6.4   3.5 |  -6.0  21.2  100   5  3   6.6   3.6
 12000  -5.1  22.8  150   7  3   6.5   3.6 |  -5.0  23.0  080   5  2   6.6   3.6
 11500  -4.2  24.4  155   6  3   5.4   2.9 |  -4.1  24.6  060   5  2   6.0   3.3
 11000  -3.4  25.9  155   6  3   5.6   3.1 |  -3.2  26.2  045   5  3   6.1   3.3
 10500  -2.9  26.8  150   5  2   1.4   0.7 |  -2.5  27.5  035   7  3   4.7   2.6
 10250  -2.8  27.0  150   4  2   2.9   1.6 |  -2.1  28.2  030   7  4   5.5   3.0
 10000  -2.5  27.5  145   4  2   5.4   3.0 |  -1.7  28.9  025   8  4   6.6   3.6
  9750  -2.1  28.2  135   3  2   6.5   3.6 |  -1.2  29.8  025   8  4   6.6   3.6
  9500  -1.6  29.1  115   3  1   6.4   3.5 |  -0.7  30.7  020   7  4   6.5   3.6
  9250  -1.2  29.8  095   2  1   6.6   3.6 |  -0.2  31.6  010   7  4   6.5   3.6
  9000  -0.7  30.7  070   3  1   5.8   3.2 |   0.2  32.4  010   7  4   6.0   3.3
  8750  -0.4  31.3  060   3  2   5.1   2.8 |   0.6  33.1  360   7  3   5.9   3.3
  8500   0.0  32.0  045   3  2   5.6   3.1 |   1.1  34.0  350   6  3   6.6   3.6
  8250   0.4  32.7  035   3  2   5.3   2.9 |   1.5  34.7  340   6  3   5.4   3.0
  8000   0.8  33.4  025   4  2   6.0   3.3 |   1.9  35.4  330   7  3   9.8   5.4
  7750   1.3  34.3  010   4  2   5.6   3.1 |   2.8  37.0  325   7  3  11.5   6.3
  7500   1.6  34.9  360   4  2   4.7   2.6 |   3.5  38.3  320   7  3   8.4   4.6
  7250   2.0  35.6  350   5  2   4.9   2.7 |   4.2  39.6  315   7  3   9.4   5.2
  7000   2.3  36.1  340   5  2   5.4   3.0 |   4.9  40.8  315   7  3   9.6   5.3
  6750   2.8  37.0  330   5  2   6.9   3.8 |   5.6  42.1  310   6  3  10.1   5.5
  6500   3.3  37.9  325   5  2   6.8   3.7 |   6.3  43.3  310   6  3   9.7   5.3
  6250   3.8  38.8  315   5  2   8.7   4.8 |   7.1  44.8  305   6  3  11.0   6.0
  6000   4.5  40.1  310   5  2  10.6   5.8 |   8.0  46.4  305   6  3  12.2   6.7
  5750   5.2  41.4  310   4  2   9.4   5.2 |   8.8  47.8  305   6  3  10.4   5.7
  5500   5.9  42.6  305   4  2   9.7   5.3 |   9.6  49.3  300   6  3  12.3   6.8
  5250   6.7  44.1  310   4  2  11.3   6.2 |  10.7  51.3  300   6  3  19.2  10.6
  5000     M     M    M   M  M     M     M |     M     M    M   M  M     M     M

           04/26/2015 at 1500 MDT          |       04/26/2015 at 1800 MDT
                                           |
K index... +23.5  LI... +272.7             | K index... +25.6  LI... +272.6
CAPE... +55.0  CIN... -4.8                 | CAPE... +58.7  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 -55.2 -67.4  330  23 12   1.2   0.7 | -55.4 -67.7  345  28 14   1.1   0.6
 45000 -53.4 -64.1  340  28 14   1.0   0.6 | -53.7 -64.7  355  32 16   1.1   0.6
 40000 -52.8 -63.0  330  18  9   0.4   0.2 | -53.0 -63.4  350  26 13   0.4   0.2
 38000 -52.9 -63.2  330   9  4  -1.4  -0.7 | -53.5 -64.3  355  17  9  -2.4  -1.3
 36000 -53.7 -64.7  135   9  5  -1.4  -0.7 | -54.9 -66.8  080   7  4  -2.4  -1.3
 34000 -54.6 -66.3  140  27 14   1.1   0.6 | -55.9 -68.6  130  20 10   6.6   3.6
 32000 -50.7 -59.3  140  28 14   6.0   3.3 | -51.0 -59.8  120  19 10   8.1   4.5
 30000 -46.9 -52.4  140  27 14   9.4   5.1 | -46.1 -51.0  110  17  9   9.1   5.0
 29000 -44.1 -47.4  140  25 13   9.0   5.0 | -43.4 -46.1  110  16  8   9.0   4.9
 28000 -41.4 -42.5  140  23 12   9.0   5.0 | -40.7 -41.3  105  14  7   9.0   4.9
 27000 -38.7 -37.7  145  20 11   9.0   5.0 | -38.0 -36.4  105  13  7   9.1   5.0
 26000 -36.1 -33.0  145  18 10   8.8   4.8 | -34.9 -30.8  100  11  6   8.3   4.5
 25000 -33.4 -28.1  145  17  8   8.8   4.8 | -32.4 -26.3  095  10  5   8.3   4.6
 24000 -30.8 -23.4  140  15  7   8.9   4.9 | -29.9 -21.8  095   8  4   8.3   4.5
 23000 -28.4 -19.1  140  13  7   7.9   4.3 | -27.6 -17.7  085   7  4   7.6   4.2
 22000 -26.0 -14.8  135  12  6   7.9   4.3 | -25.4 -13.7  080   6  3   7.6   4.2
 21000 -23.7 -10.7  130  10  5   7.9   4.3 | -23.1  -9.6  070   5  3   7.6   4.2
 20000 -21.5  -6.7  125   9  5   7.5   4.1 | -20.9  -5.6  055   4  2   7.7   4.2
 19500 -20.3  -4.5  120   9  5   7.5   4.1 | -19.7  -3.5  045   4  2   7.7   4.2
 19000 -19.2  -2.6  120   8  4   7.5   4.1 | -18.6  -1.5  035   4  2   7.7   4.2
 18500 -18.1  -0.6  115   8  4   7.5   4.1 | -17.5   0.5  020   4  2   7.6   4.2
 18000 -17.1   1.2  115   7  4   7.0   3.8 | -16.4   2.5  015   4  2   7.2   4.0
 17500 -16.0   3.2  110   7  3   7.1   3.9 | -15.3   4.5  010   4  2   7.3   4.0
 17000 -15.0   5.0  105   6  3   6.9   3.8 | -14.3   6.3  005   4  2   7.0   3.8
 16500 -14.0   6.8  100   6  3   6.8   3.7 | -13.3   8.1  005   4  2   6.9   3.8
 16000 -13.0   8.6  095   5  3   6.8   3.7 | -12.3   9.9  005   4  2   6.8   3.7
 15500 -12.0  10.4  090   5  2   6.7   3.7 | -11.3  11.7  010   4  2   6.5   3.6
 15000 -10.5  13.1  075   4  2   6.8   3.7 | -10.4  13.3  015   5  2   6.5   3.6
 14500  -9.5  14.9  065   4  2   6.8   3.7 |  -9.4  15.1  020   6  3   6.8   3.7
 14000  -8.5  16.7  060   4  2   6.9   3.8 |  -8.4  16.9  025   7  4   6.8   3.7
 13500  -7.5  18.5  040   6  3   7.1   3.9 |  -7.5  18.5  030  10  5   6.3   3.5
 13000  -6.5  20.3  025   8  4   7.1   3.9 |  -6.1  21.0  030  15  8   6.4   3.5
 12500  -5.4  22.3  020  10  5   7.2   4.0 |  -5.2  22.6  025  18  9   6.3   3.4
 12000  -4.4  24.1  020  12  6   7.2   3.9 |  -4.3  24.3  020  21 11   6.3   3.4
 11500  -3.3  26.1  015  12  6   6.8   3.7 |  -3.4  25.9  020  22 11   6.2   3.4
 11000  -2.4  27.7  010  13  7   6.8   3.7 |  -2.5  27.5  015  22 12   6.2   3.4
 10500  -1.4  29.5  360  12  6   6.1   3.3 |  -1.6  29.1  010  22 11   6.2   3.4
 10250  -1.0  30.2  355  11  6   6.8   3.7 |  -1.1  30.0  005  22 11   6.3   3.5
 10000  -0.4  31.3  345  10  5   7.6   4.2 |  -0.7  30.7  005  21 11   7.1   3.9
  9750   0.1  32.2  340  10  5   7.6   4.2 |  -0.1  31.8  360  20 11   8.0   4.4
  9500   0.6  33.1  335  10  5   7.7   4.2 |   0.5  32.9  360  20 10   8.4   4.6
  9250   1.2  34.2  330  10  5   7.4   4.1 |   1.1  34.0  360  19 10   7.7   4.2
  9000   1.7  35.1  325  10  5   8.0   4.4 |   1.6  34.9  355  19 10   8.3   4.5
  8750   2.4  36.3  325  10  5   9.2   5.0 |   2.3  36.1  355  19 10   9.7   5.3
  8500   3.1  37.6  320  10  5   9.5   5.2 |   3.0  37.4  355  18  9   9.4   5.2
  8250   3.7  38.7  320  10  5   9.3   5.1 |   3.7  38.7  355  18  9  10.4   5.7
  8000   4.4  39.9  320  10  5  10.6   5.8 |   4.5  40.1  355  18  9  10.7   5.9
  7750   5.3  41.5  315   9  5  10.4   5.7 |   5.2  41.4  355  17  9   9.2   5.1
  7500   6.0  42.8  315   9  5   9.1   5.0 |   5.9  42.6  350  17  9   8.7   4.8
  7250   6.7  44.1  315   9  5   9.9   5.4 |   6.5  43.7  350  16  8   9.5   5.2
  7000   7.4  45.3  315   9  5  10.5   5.8 |   7.3  45.1  350  16  8  10.4   5.7
  6750   8.2  46.8  310   9  5  10.2   5.6 |   8.0  46.4  350  15  8  10.1   5.5
  6500   8.9  48.0  310   9  5   9.4   5.2 |   8.8  47.8  350  15  8   9.8   5.4
  6250   9.7  49.5  310   9  4  10.9   6.0 |   9.5  49.1  350  14  7  10.1   5.5
  6000  10.6  51.1  305   9  4  12.1   6.7 |  10.3  50.5  345  14  7  10.2   5.6
  5750  11.4  52.5  305   8  4   9.8   5.4 |  11.0  51.8  345  13  7  10.2   5.6
  5500  12.1  53.8  305   8  4  11.7   6.4 |  11.8  53.2  345  11  6   9.9   5.4
  5250  13.3  55.9  305   8  4  20.0  11.0 |  12.4  54.3  345  11  6   9.1   5.0
  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



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