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 051221
SRGGJT

Soaring Forecast
National Weather Service Grand Junction, Colorado
0621 MDT Thursday, May 5, 2016

This forecast is for Thursday, May 5, 2016:

If the trigger temperature of 76.4 F/24.7 C is reached...then
   Thermal Soaring Index....................... Excellent
   Maximum rate of lift........................ 1224 ft/min (6.2 m/s)
   Maximum height of thermals.................. 18674 ft MSL (13835 ft AGL)

Forecast maximum temperature................... 84.0 F/29.3 C
Time of trigger temperature.................... 1200 MDT
Time of overdevelopment........................ 1500 MDT
Middle/high clouds during soaring window....... Overcast thin high
Surface winds during soaring window............ 20 mph or less
Height of the -3 thermal index................. 11498 ft MSL (6659 ft AGL)
Thermal soaring outlook for Friday 05/06....... Excellent

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

Remarks...

Sunrise/Sunset.................... 06:10:43 / 20:10:39 MDT
Total possible sunshine........... 13 hr 59 min 56 sec (839 min 56 sec)
Altitude of sun at 13:10:52 MDT... 67.42 degrees

Upper air data from rawinsonde observation taken on 05/05/2016 at 0600 MDT

Freezing level.................. 13490 ft MSL (8651 ft AGL)
Convective condensation level... 17336 ft MSL (12497 ft AGL)
Lifted condensation level....... 18591 ft MSL (13752 ft AGL)
Lifted index.................... +2.3
K index......................... +11.2

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  -63.0 -81.4   250   47   24   0.4   0.2   94.7 202.4    37.6      M    M
 45000  -68.6 -91.5   260   77   40  -4.1  -2.2   60.6 141.0    19.4      M    M
 40000  -60.9 -77.6   265   50   26   6.9   3.8   48.4 119.0    12.9      M    M
 38000  -56.8 -70.2   255   38   20   8.9   4.9   45.7 114.3    11.4      M    M
 36000  -51.4 -60.5   240   29   15   9.0   4.9   45.2 113.4    11.4      M    M
 34000  -46.2 -51.2   235   33   17   8.1   4.4   44.2 111.6    11.0      M    M
 32000  -42.1 -43.8   230   40   20   3.4   1.8   42.0 107.6     9.6      M    M
 30000  -38.0 -36.4   230   33   17   8.2   4.5   38.6 101.4     7.3      M    M
 29000  -35.6 -32.1   230   31   16   8.2   4.5   38.0 100.4     6.9      M    M
 28000  -33.1 -27.6   240   23   12   8.1   4.4   37.3  99.2     6.5      M    M
 27000  -30.4 -22.7   255   17    9   9.4   5.2   37.1  98.8     6.4      M    M
 26000  -27.6 -17.7   250   13    7   9.4   5.2   36.9  98.5     6.3      M    M
 25000  -24.7 -12.5   245    9    5   9.4   5.2   36.9  98.3     6.4      M    M
 24000  -21.9  -7.4   240   11    6   9.2   5.0   36.7  98.0     6.3      M    M
 23000  -19.6  -3.3   235   14    7   5.3   2.9   35.9  96.7     5.8      M    M
 22000  -17.7   0.1   235   17    9   7.7   4.2   34.8  94.6     4.9      M    M
 21000  -15.3   4.5   230   20   10   7.8   4.3   34.0  93.3     4.3      M    M
 20000  -13.1   8.4   230   23   12   2.6   1.4   33.3  91.9     3.8      M    M
 19500  -13.3   8.1   230   23   12   0.9   0.5   31.4  88.6     2.2      M    M
 19000  -12.8   9.0   225   24   12   6.7   3.7   30.3  86.6     1.2      M    M
 18500  -13.0   8.6   235   23   12  -8.5  -4.7   28.5  83.3    -0.4   1327  6.7
 18000  -13.1   8.4   240   21   11   5.3   2.9   26.8  80.2    -2.1   1317  6.7
 17500  -12.2  10.0   245   20   10   9.3   5.1   26.2  79.2    -2.7   1276  6.5
 17000  -10.8  12.6   250   19   10   9.8   5.3   26.2  79.2    -2.7   1218  6.2
 16500   -8.6  16.5   250   19   10   9.8   5.4   26.3  79.3    -2.7   1130  5.7
 16000   -7.1  19.2   250   19   10   9.8   5.4   26.3  79.3    -2.7   1072  5.4
 15500   -5.7  21.7   250   18    9   9.8   5.4   26.3  79.3    -2.7   1013  5.1
 15000   -4.2  24.4   245   18    9   9.8   5.4   26.2  79.2    -2.7    954  4.8
 14500   -2.8  27.0   245   17    9   9.8   5.4   26.3  79.3    -2.8    896  4.6
 14000   -1.3  29.7   245   17    9   9.8   5.4   26.3  79.3    -2.8    837  4.3
 13500    0.2  32.4   245   17    9   9.7   5.3   26.2  79.2    -2.8    779  4.0
 13000    1.6  34.9   240   17    9   9.6   5.2   26.2  79.2    -2.9    721  3.7
 12500    3.0  37.4   240   17    9   9.6   5.2   26.2  79.1    -2.9    664  3.4
 12000    4.4  39.9   240   17    9   9.6   5.2   26.2  79.1    -2.9    607  3.1
 11500    5.9  42.6   230   18    9   9.6   5.2   26.1  79.0    -3.0    549  2.8
 11000    7.3  45.1   225   18    9   9.6   5.2   26.1  78.9    -3.1    492  2.5
 10500    8.7  47.7   215   20   10   9.5   5.2   26.1  78.9    -3.1    435  2.2
 10250    9.4  48.9   215   20   10   8.9   4.9   26.0  78.8    -3.2    407  2.1
 10000   10.0  50.0   210   20   10   8.5   4.7   25.9  78.6    -3.3    380  1.9
  9750   10.7  51.3   205   21   11   8.6   4.7   25.8  78.5    -3.4    353  1.8
  9500   11.3  52.3   200   21   11   8.6   4.7   25.7  78.3    -3.4    327  1.7
  9250   12.0  53.6   195   22   11   8.3   4.5   25.6  78.2    -3.5    300  1.5
  9000   12.5  54.5   190   23   12   5.3   2.9   25.5  77.8    -3.7    277  1.4
  8750   12.8  55.0   190   23   12   3.7   2.0   25.0  77.0    -4.2    261  1.3
  8500   13.1  55.6   185   23   12   3.7   2.0   24.5  76.2    -4.6    245  1.2
  8250   13.4  56.1   185   23   12   5.3   2.9   24.1  75.4    -5.1    229  1.2
  8000   13.9  57.0   180   23   12   7.6   4.1   23.9  75.0    -5.3    206  1.0
  7750   14.4  57.9   175   23   12   7.3   4.0   23.7  74.6    -5.5    182  0.9
  7500   15.0  59.0   170   22   12   7.7   4.2   23.5  74.3    -5.7    158  0.8
  7250   15.5  59.9   160   23   12   6.3   3.4   23.3  74.0    -5.9    135  0.7
  7000   15.8  60.4   155   23   12   1.4   0.8   22.9  73.2    -6.4    119  0.6
  6750   15.7  60.3   150   23   12  -0.6  -0.3   22.1  71.8    -7.2    113  0.6
  6500   15.7  60.3   150   24   12  -0.0  -0.0   21.4  70.5    -8.0    106  0.5
  6250   15.7  60.3   145   24   12  -0.3  -0.1   20.6  69.1    -8.7    100  0.5
  6000   15.6  60.1   140   25   13   0.2   0.1   19.9  67.8    -9.5     94  0.5
  5750   15.7  60.3   135   23   12   2.6   1.4   19.2  66.6   -10.2     85  0.4
  5500   16.1  61.0   135   19   10   8.9   4.9   18.9  66.0   -10.6     67  0.3
  5250   16.4  61.5   125   16    8  -6.4  -3.5   18.6  65.4   -11.0     48  0.2
  5000   14.6  58.3   115   13    7 -40.0 -21.9   16.0  60.8   -13.6     96  0.5

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

           05/05/2016 at 0900 MDT          |       05/05/2016 at 1200 MDT
                                           |
K index... +18.9  LI... +273.8             | K index... +14.9  LI... +272.3
CAPE... 0.0  CIN... -13.8                  | CAPE... +20.8  CIN... -57.5
                                           |
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 -65.0 -85.0  260  37 19  -1.4  -0.7 | -64.0 -83.2  250  32 16  -1.0  -0.5
 45000 -66.4 -87.5  250  56 29   3.3   1.8 | -64.8 -84.6  250  53 27   2.6   1.4
 40000 -61.1 -78.0  260  55 28   4.2   2.3 | -60.9 -77.6  250  61 31   2.9   1.6
 38000 -56.3 -69.3  250  42 22   8.3   4.5 | -56.6 -69.9  245  52 27   7.6   4.2
 36000 -51.4 -60.5  230  30 16   8.3   4.5 | -52.0 -61.6  230  43 22   7.6   4.2
 34000 -46.6 -51.9  225  30 15   7.6   4.2 | -47.3 -53.1  225  41 21   8.1   4.5
 32000 -42.1 -43.8  230  35 18   7.6   4.2 | -42.4 -44.3  225  43 22   8.1   4.4
 30000 -37.8 -36.0  230  33 17   6.8   3.7 | -37.9 -36.2  225  37 19   7.1   3.9
 29000 -35.8 -32.4  230  28 14   6.8   3.7 | -35.3 -31.5  225  30 15   7.1   3.9
 28000 -33.2 -27.8  235  22 11   6.5   3.6 | -33.1 -27.6  220  23 12   6.8   3.8
 27000 -30.7 -23.3  230  19 10   9.0   4.9 | -30.6 -23.1  215  21 11   8.8   4.8
 26000 -28.0 -18.4  230  17  9   9.0   4.9 | -28.0 -18.4  210  20 10   8.8   4.8
 25000 -25.3 -13.5  225  16  8   9.0   4.9 | -25.4 -13.7  200  19 10   8.8   4.8
 24000 -22.7  -8.9  225  15  8   8.4   4.6 | -23.0  -9.4  200  18  9   7.3   4.0
 23000 -20.2  -4.4  230  14  7   8.4   4.6 | -20.8  -5.4  200  17  9   7.3   4.0
 22000 -17.7   0.1  230  14  7   8.7   4.8 | -18.6  -1.5  205  16  8   7.4   4.1
 21000 -16.1   3.0  235  14  7   3.9   2.1 | -16.9   1.6  210  14  7   4.8   2.6
 20000 -14.9   5.2  235  13  7   3.9   2.1 | -15.5   4.1  225  12  6   4.8   2.6
 19500 -14.4   6.1  235  13  7   4.0   2.2 | -14.8   5.4  235  11  6   4.9   2.7
 19000 -13.8   7.2  240  13  7   4.8   2.6 | -14.1   6.6  245  11  6   6.4   3.5
 18500 -13.0   8.6  235  14  7   5.7   3.1 | -12.9   8.8  245  12  6   7.9   4.4
 18000 -12.2  10.0  230  15  8   5.7   3.1 | -11.8  10.8  245  13  7   8.1   4.5
 17500 -11.2  11.8  225  15  8   8.5   4.7 | -10.6  12.9  240  14  7   8.2   4.5
 17000 -10.1  13.8  225  14  7   8.3   4.6 |  -9.4  15.1  225  14  7   8.2   4.5
 16500  -8.9  16.0  225  14  7   9.2   5.0 |  -8.2  17.2  215  15  8   9.1   5.0
 16000  -7.4  18.7  225  14  7   9.6   5.3 |  -6.8  19.8  215  15  8   9.5   5.2
 15500  -6.0  21.2  230  13  7   9.5   5.2 |  -5.4  22.3  215  15  8   9.4   5.2
 15000  -4.6  23.7  230  13  7   9.1   5.0 |  -4.0  24.8  215  14  7   9.1   5.0
 14500  -3.3  26.1  235  12  6   9.1   5.0 |  -2.7  27.1  210  13  7   9.1   5.0
 14000  -1.9  28.6  235  12  6   9.4   5.2 |  -0.7  30.7  210  12  6   8.9   4.9
 13500   0.2  32.4  235  11  6   9.3   5.1 |   0.6  33.1  205  11  6   8.9   4.9
 13000   1.6  34.9  235  11  6   9.2   5.0 |   1.9  35.4  205  10  5   8.9   4.9
 12500   3.0  37.4  240  11  6   9.1   5.0 |   3.3  37.9  205   9  4   8.9   4.9
 12000   4.3  39.7  240  11  6   9.0   4.9 |   4.6  40.3  205   8  4   8.9   4.9
 11500   5.7  42.3  240  11  5   8.9   4.9 |   5.9  42.6  200   6  3   8.9   4.9
 11000   6.9  44.4  235  11  5   8.0   4.4 |   7.3  45.1  195   5  3   8.8   4.8
 10500   8.2  46.8  230  11  5   4.8   2.6 |   8.6  47.5  190   5  2   5.1   2.8
 10250   8.4  47.1  230  11  5   5.8   3.2 |   8.8  47.8  185   4  2   5.9   3.2
 10000   9.1  48.4  225  11  5  10.9   6.0 |   9.6  49.3  180   4  2  11.4   6.3
  9750   9.9  49.8  220  11  5   9.8   5.4 |  10.4  50.7  175   4  2  10.3   5.7
  9500  10.6  51.1  215  11  5   8.9   4.9 |  11.1  52.0  170   4  2   9.1   5.0
  9250  11.1  52.0  210  11  6   6.4   3.5 |  11.7  53.1  160   4  2   7.2   3.9
  9000  11.6  52.9  205  11  6   6.2   3.4 |  12.3  54.1  160   4  2   8.7   4.8
  8750  12.1  53.8  200  11  6   6.7   3.7 |  13.0  55.4  155   4  2   9.6   5.3
  8500  12.6  54.7  190  12  6   6.0   3.3 |  13.7  56.7  150   5  2   8.8   4.8
  8250  13.0  55.4  185  12  6   5.2   2.9 |  14.3  57.7  150   5  3   8.2   4.5
  8000  13.4  56.1  180  12  6   5.0   2.7 |  14.9  58.8  150   5  3   7.3   4.0
  7750  13.7  56.7  175  12  6   4.8   2.6 |  15.3  59.5  145   6  3   6.3   3.5
  7500  14.1  57.4  170  12  6   4.1   2.3 |  15.8  60.4  145   6  3   7.7   4.2
  7250  14.3  57.7  165  11  6   3.6   2.0 |  16.4  61.5  145   6  3   8.7   4.8
  7000  14.6  58.3  160  11  6   3.6   2.0 |  17.0  62.6  145   6  3   8.5   4.7
  6750  14.8  58.6  155  11  5   2.4   1.3 |  17.6  63.7  140   6  3   9.4   5.2
  6500  14.9  58.8  150  10  5   0.5   0.3 |  18.4  65.1  140   6  3  10.5   5.8
  6250  14.9  58.8  145   8  4   0.7   0.4 |  19.2  66.6  145   6  3  11.4   6.3
  6000  14.9  58.8  135   7  3  -1.4  -0.8 |  20.0  68.0  145   6  3   9.7   5.3
  5750  14.7  58.5  110   5  3   2.4   1.3 |  20.7  69.3  145   5  3  11.2   6.2
  5500  15.2  59.4  105   5  3   8.7   4.8 |  21.7  71.1  145   5  3  14.6   8.0
  5250  15.6  60.1  105   5  2   3.8   2.1 |  22.7  72.9  145   5  3  11.9   6.6
  5000     M     M    M   M  M     M     M |     M     M    M   M  M     M     M

           05/05/2016 at 1500 MDT          |       05/05/2016 at 1800 MDT
                                           |
K index... +20.6  LI... +272.4             | K index... +19.6  LI... +272.2
CAPE... +20.8  CIN... -35.6                | CAPE... +49.0  CIN... -29.3
                                           |
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 -63.9 -83.0  235  34 17  -0.8  -0.4 | -64.3 -83.7  230  33 17  -1.1  -0.6
 45000 -64.5 -84.1  240  51 26   2.2   1.2 | -65.4 -85.7  235  49 25   2.8   1.5
 40000 -61.2 -78.2  250  61 31   2.5   1.4 | -61.2 -78.2  240  71 36   2.7   1.5
 38000 -57.0 -70.6  240  53 27   7.5   4.1 | -57.2 -71.0  240  58 30   7.1   3.9
 36000 -52.5 -62.5  235  45 23   7.5   4.1 | -52.9 -63.2  230  44 22   7.1   3.9
 34000 -47.6 -53.7  225  43 22   8.7   4.8 | -48.0 -54.4  225  38 20   9.1   5.0
 32000 -42.4 -44.3  225  46 23   8.7   4.8 | -42.5 -44.5  220  40 20   9.1   5.0
 30000 -37.6 -35.7  220  41 21   7.3   4.0 | -37.4 -35.3  220  39 20   8.1   4.4
 29000 -34.9 -30.8  220  35 18   7.3   4.0 | -34.9 -30.8  215  37 19   8.1   4.4
 28000 -32.7 -26.9  220  29 15   7.1   3.9 | -31.9 -25.4  215  35 18   8.1   4.5
 27000 -30.3 -22.5  215  27 14   8.4   4.6 | -29.6 -21.3  215  33 17   7.7   4.2
 26000 -27.8 -18.0  210  26 14   8.4   4.6 | -27.3 -17.1  215  31 16   7.7   4.2
 25000 -25.2 -13.4  205  26 13   8.4   4.6 | -24.9 -12.8  210  30 15   7.7   4.2
 24000 -23.0  -9.4  200  25 13   6.7   3.7 | -22.9  -9.2  210  28 15   6.3   3.4
 23000 -21.0  -5.8  200  23 12   6.6   3.6 | -21.0  -5.8  205  27 14   6.2   3.4
 22000 -19.1  -2.4  195  22 11   6.7   3.7 | -19.1  -2.4  200  26 14   6.2   3.4
 21000 -17.2   1.0  195  20 10   6.2   3.4 | -17.1   1.2  195  25 13   7.1   3.9
 20000 -15.4   4.3  200  17  9   6.3   3.5 | -15.0   5.0  195  24 12   7.2   3.9
 19500 -14.5   5.9  200  15  8   6.5   3.5 | -14.0   6.8  195  23 12   7.3   4.0
 19000 -13.6   7.5  200  14  7   7.7   4.2 | -12.9   8.8  195  22 12   8.1   4.4
 18500 -12.3   9.9  200  13  7   9.0   4.9 | -11.6  11.1  195  22 11   9.3   5.1
 18000 -10.9  12.4  195  13  7   9.1   5.0 | -10.2  13.6  195  21 11   9.3   5.1
 17500  -9.6  14.7  195  13  7   8.8   4.8 |  -8.8  16.2  195  20 10   9.3   5.1
 17000  -8.3  17.1  195  13  6   8.8   4.8 |  -7.5  18.5  195  19 10   9.3   5.1
 16500  -7.0  19.4  195  13  6   9.0   4.9 |  -6.1  21.0  190  18  9   9.2   5.1
 16000  -5.7  21.7  195  13  7   9.1   5.0 |  -4.8  23.4  190  18  9   9.1   5.0
 15500  -4.4  24.1  195  13  7   9.1   5.0 |  -3.4  25.9  190  17  9   9.1   5.0
 15000  -3.0  26.6  195  13  7   9.1   5.0 |  -2.1  28.2  190  17  9   9.1   5.0
 14500  -1.7  28.9  195  12  6   9.1   5.0 |  -0.8  30.6  185  16  8   9.1   5.0
 14000   0.3  32.5  190  12  6   9.1   5.0 |   0.5  32.9  185  15  8   8.9   4.9
 13500   1.7  35.1  190  12  6   9.1   5.0 |   2.5  36.5  180  15  8   9.0   4.9
 13000   3.0  37.4  185  11  6   8.9   4.9 |   3.8  38.8  175  15  8   9.3   5.1
 12500   4.4  39.9  185  11  6   8.9   4.9 |   5.2  41.4  175  15  8   9.3   5.1
 12000   5.7  42.3  180  11  6   8.7   4.8 |   6.6  43.9  170  15  8   9.2   5.0
 11500   7.0  44.6  180  10  5   8.6   4.7 |   7.9  46.2  165  14  7   9.3   5.1
 11000   8.2  46.8  175  10  5   7.4   4.0 |   9.2  48.6  165  14  7   7.8   4.3
 10500   9.3  48.7  170   9  5  10.5   5.7 |  10.3  50.5  160  14  7  10.9   6.0
 10250  10.2  50.4  165   9  5  11.1   6.1 |  11.3  52.3  160  15  7  11.3   6.2
 10000  10.8  51.4  165   9  4   7.4   4.1 |  11.9  53.4  155  14  7   7.7   4.2
  9750  11.4  52.5  160   8  4   8.7   4.8 |  12.5  54.5  155  14  7   8.7   4.8
  9500  12.0  53.6  160   8  4   7.3   4.0 |  13.2  55.8  150  14  7   8.3   4.5
  9250  12.6  54.7  155   8  4   6.8   3.7 |  13.8  56.8  150  14  7   7.5   4.1
  9000  13.1  55.6  155   7  4   8.6   4.7 |  14.3  57.7  145  13  7   7.6   4.2
  8750  13.8  56.8  150   7  4   9.2   5.0 |  14.9  58.8  145  13  6   8.2   4.5
  8500  14.4  57.9  150   7  4   9.5   5.2 |  15.5  59.9  140  12  6   8.1   4.4
  8250  15.2  59.4  145   7  3  10.4   5.7 |  16.1  61.0  140  11  6   8.1   4.4
  8000  16.0  60.8  150   7  3  10.0   5.5 |  16.7  62.1  140  11  6   7.8   4.3
  7750  16.7  62.1  150   7  3   9.4   5.1 |  17.3  63.1  135  11  5   7.4   4.1
  7500  17.4  63.3  150   6  3  10.1   5.5 |  17.8  64.0  135  10  5   8.2   4.5
  7250  18.2  64.8  150   6  3  10.8   5.9 |  18.5  65.3  135  10  5   9.9   5.5
  7000  19.0  66.2  150   6  3  10.2   5.6 |  19.2  66.6  135   9  5  10.1   5.5
  6750  19.7  67.5  150   6  3   9.6   5.3 |  20.2  68.4  135   9  5   9.2   5.0
  6500  20.4  68.7  150   6  3  10.3   5.7 |  20.7  69.3  135   9  5  10.0   5.5
  6250  21.2  70.2  150   6  3  11.1   6.1 |  21.4  70.5  135   9  5  11.0   6.0
  6000  22.0  71.6  150   6  3  10.1   5.5 |  22.2  72.0  135   8  4  10.4   5.7
  5750  22.8  73.0  150   5  3  11.2   6.1 |  23.0  73.4  135   8  4   9.2   5.1
  5500  23.7  74.7  150   5  3  14.2   7.8 |  23.6  74.5  135   8  4   8.9   4.9
  5250  24.8  76.6  150   5  3  14.0   7.7 |  24.3  75.7  135   8  4   9.5   5.2
  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.