Soaring Guidance
Issued by NWS Grand Junction, CO

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000
UXUS97 KGJT 181218
SRGGJT

Soaring Forecast
National Weather Service Grand Junction, Colorado
0518 MST Saturday, February 18, 2017

This forecast is for Saturday, February 18, 2017:

If the trigger temperature of 54.1 F/12.3 C is reached...then
   Thermal Soaring Index....................... Poor
   Maximum rate of lift........................ 0 ft/min (0.0 m/s)
   Maximum height of thermals.................. 7369 ft MSL (2530 ft AGL)

Forecast maximum temperature................... 53.0 F/12.1 C
Time of trigger temperature.................... 1415 MST
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................. 5262 ft MSL (423 ft AGL)
Thermal soaring outlook for Sunday 02/19....... Poor

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

Remarks...

Sunrise/Sunset.................... 07:01:16 / 17:53:55 MST
Total possible sunshine........... 10 hr 52 min 38 sec (652 min 38 sec)
Altitude of sun at 12:27:52 MST... 39.56 degrees

Upper air data from rawinsonde observation taken on 02/18/2017 at 0500 MST

Freezing level.................. 8962 ft MSL (4123 ft AGL)
Convective condensation level... 11039 ft MSL (6200 ft AGL)
Lifted condensation level....... 10273 ft MSL (5433 ft AGL)
Lifted index.................... +8.0
K index......................... +16.0

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  -60.6 -77.1   240   19   10   7.8   4.3   99.0 210.2    49.9      M    M
 45000  -52.2 -62.0   225   53   27  -1.9  -1.1   87.3 189.1    46.4      M    M
 40000  -45.6 -50.1   225   66   34  -2.1  -1.1   74.5 166.1    41.1      M    M
 38000  -49.2 -56.6   230   79   41 -12.8  -7.0   60.5 140.8    32.8      M    M
 36000  -58.1 -72.6   220   72   37   1.4   0.8   38.8 101.8    18.7      M    M
 34000  -53.7 -64.7   205   68   35   9.4   5.2   36.6  97.9    17.7      M    M
 32000  -47.4 -53.3   210   60   31   9.4   5.2   36.2  97.2    17.9      M    M
 30000  -41.9 -43.4   215   58   30   9.2   5.1   35.9  96.7    18.2      M    M
 29000  -39.1 -38.4   220   61   31   9.2   5.1   35.7  96.3    18.2      M    M
 28000  -36.4 -33.5   225   64   33   8.9   4.9   35.5  95.8    18.2      M    M
 27000  -34.0 -29.2   230   67   34   7.3   4.0   34.8  94.6    17.9      M    M
 26000  -31.9 -25.4   230   62   32   7.3   4.0   33.8  92.8    17.3      M    M
 25000  -29.6 -21.3   230   57   29   8.4   4.6   33.0  91.4    16.9      M    M
 24000  -27.1 -16.8   235   59   30   8.3   4.6   32.4  90.4    16.6      M    M
 23000  -25.1 -13.2   235   54   28   6.4   3.5   31.4  88.5    15.9      M    M
 22000  -23.4 -10.1   235   48   25   5.4   3.0   29.9  85.8    14.9      M    M
 21000  -21.8  -7.2   230   48   25   5.4   3.0   28.3  82.9    13.7      M    M
 20000  -19.8  -3.6   225   49   25   7.9   4.3   27.2  81.0    13.0      M    M
 19500  -18.6  -1.5   220   49   25   7.9   4.4   26.9  80.4    12.8      M    M
 19000  -17.4   0.7   220   49   25   8.4   4.6   26.6  79.8    12.5      M    M
 18500  -16.7   1.9   215   50   26   2.6   1.4   25.8  78.4    11.9      M    M
 18000  -16.5   2.3   215   51   26   1.9   1.0   24.3  75.7    10.7      M    M
 17500  -15.7   3.7   215   50   26   5.5   3.0   23.5  74.3    10.1      M    M
 17000  -14.2   6.4   215   47   24   7.8   4.3   22.7  72.9     9.5      M    M
 16500  -13.1   8.4   215   45   23   7.4   4.1   22.4  72.4     9.2      M    M
 16000  -12.0  10.4   215   43   22   3.6   2.0   21.9  71.5     8.8      M    M
 15500  -12.3   9.9   215   39   20   0.3   0.2   20.2  68.3     7.2      M    M
 15000  -11.5  11.3   215   35   18   7.4   4.1   19.4  66.9     6.5      M    M
 14500  -10.5  13.1   215   31   16   8.3   4.6   18.9  66.1     6.1      M    M
 14000  -10.1  13.8   215   27   14  -4.2  -2.3   17.7  63.8     5.1      M    M
 13500  -10.3  13.5   215   23   12   3.2   1.7   15.9  60.6     3.5      M    M
 13000   -9.4  15.1   220   19   10   7.2   4.0   15.3  59.6     3.0      M    M
 12500   -8.3  17.1   220   18    9   7.1   3.9   14.9  58.9     2.6      M    M
 12000   -7.2  19.0   220   17    9   8.4   4.6   14.6  58.3     2.3      M    M
 11500   -6.0  21.2   220   19   10   8.3   4.6   14.4  57.9     2.0      M    M
 11000   -4.7  23.5   220   20   10   8.3   4.5   14.2  57.5     1.8      M    M
 10500   -3.5  25.7   215   21   11   7.6   4.2   13.9  57.1     1.6      M    M
 10250   -3.0  26.6   210   21   11   5.6   3.1   13.7  56.6     1.4      M    M
 10000   -2.6  27.3   205   22   11   6.6   3.6   13.3  56.0     1.0      M    M
  9750   -2.0  28.4   205   22   11   8.5   4.7   13.2  55.7     0.9      M    M
  9500   -1.4  29.5   205   22   12   8.7   4.8   13.1  55.6     0.8      M    M
  9250   -0.8  30.6   200   23   12   8.6   4.7   13.0  55.4     0.7      M    M
  9000   -0.1  31.8   200   23   12   8.6   4.7   13.0  55.3     0.6      M    M
  8750    0.5  32.9   195   22   11   8.6   4.7   12.9  55.1     0.5      M    M
  8500    1.1  34.0   190   22   11   8.6   4.7   12.8  55.0     0.4      M    M
  8250    1.8  35.2   180   21   11   8.6   4.7   12.7  54.8     0.4      M    M
  8000    2.4  36.3   175   21   11   8.6   4.7   12.6  54.7     0.3      M    M
  7750    3.0  37.4   170   20   10   8.6   4.7   12.5  54.5     0.2      M    M
  7500    3.7  38.7   170   19   10   8.6   4.7   12.4  54.4     0.1      M    M
  7250    4.3  39.7   165   19   10   8.7   4.8   12.3  54.2    -0.0     99  0.5
  7000    4.9  40.8   160   18    9   8.5   4.7   12.3  54.1    -0.1     73  0.4
  6750    5.6  42.1   160   18    9   9.1   5.0   12.2  53.9    -0.2     47  0.2
  6500    6.2  43.2   160   18    9   6.9   3.8   12.1  53.7    -0.3     20  0.1
  6250    6.5  43.7   160   18    9   3.4   1.9   11.7  53.0    -0.7      3  0.0
  6000    6.7  44.1   160   18    9   2.9   1.6   11.2  52.1    -1.3      M    M
  5750    6.9  44.4   155   15    8   3.1   1.7   10.7  51.2    -1.8      M    M
  5500    7.1  44.8   150   12    6   3.0   1.6   10.2  50.3    -2.3      M    M
  5250    7.4  45.3   135    9    5   3.4   1.9    9.6  49.4    -2.9      M    M
  5000    7.6  45.7   110    7    4   1.9   1.0    9.2  48.5    -3.4      M    M

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

           02/18/2017 at 0800 MST          |       02/18/2017 at 1100 MST
                                           |
K index... +21.9  LI... +2.3               | K index... +22.1  LI... +2.6
CAPE... +0.5  CIN... -8.3                  | CAPE... 0.0  CIN... -0.7
                                           |
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 -60.8 -77.4  225  38 19   4.7   2.6 | -60.7 -77.3  225  38 20   4.6   2.5
 45000 -53.8 -64.8  220  57 29   4.4   2.4 | -53.8 -64.8  220  59 30   4.5   2.5
 40000 -47.0 -52.6  225  63 32   4.3   2.3 | -46.8 -52.2  220  62 32   4.5   2.5
 38000 -47.4 -53.3  225  66 34  -5.4  -3.0 | -46.9 -52.4  215  68 35  -5.2  -2.8
 36000 -50.6 -59.1  215  70 36  -5.5  -3.0 | -50.1 -58.2  210  79 40  -5.2  -2.9
 34000 -53.2 -63.8  210  75 39   7.4   4.1 | -52.7 -62.9  210  88 45   5.6   3.0
 32000 -48.1 -54.6  210  67 34   8.5   4.7 | -47.8 -54.0  205  83 42   8.1   4.5
 30000 -43.1 -45.6  210  60 31   8.7   4.7 | -43.0 -45.4  200  77 40   7.7   4.2
 29000 -40.5 -40.9  210  61 31   8.4   4.6 | -40.8 -41.4  205  75 39   7.4   4.0
 28000 -37.4 -35.3  215  63 32   8.4   4.6 | -38.1 -36.6  210  72 37   7.4   4.0
 27000 -34.9 -30.8  215  64 33   8.1   4.5 | -35.9 -32.6  215  70 36   7.4   4.1
 26000 -32.6 -26.7  220  61 31   7.3   4.0 | -33.6 -28.5  210  66 34   7.8   4.3
 25000 -30.5 -22.9  220  57 29   7.3   4.0 | -31.2 -24.2  205  60 31   7.8   4.3
 24000 -28.3 -18.9  225  54 28   7.4   4.1 | -28.9 -20.0  205  55 29   7.9   4.4
 23000 -26.2 -15.2  225  50 26   6.9   3.8 | -26.8 -16.2  200  51 26   6.8   3.8
 22000 -24.1 -11.4  225  47 24   6.9   3.8 | -24.8 -12.6  200  46 24   6.9   3.8
 21000 -22.1  -7.8  225  44 23   6.7   3.7 | -22.7  -8.9  200  41 21   6.9   3.8
 20000 -20.2  -4.4  220  41 21   6.1   3.3 | -20.7  -5.3  200  38 20   7.1   3.9
 19500 -19.3  -2.7  220  40 20   6.1   3.4 | -19.6  -3.3  200  37 19   7.1   3.9
 19000 -18.4  -1.1  220  38 20   6.1   3.4 | -18.6  -1.5  200  36 19   7.1   3.9
 18500 -17.6   0.3  215  37 19   6.1   3.4 | -17.6   0.3  200  35 18   7.1   3.9
 18000 -16.6   2.1  215  35 18   6.5   3.6 | -16.5   2.3  200  33 17   6.7   3.7
 17500 -15.7   3.7  215  34 18   6.5   3.6 | -15.6   3.9  200  31 16   6.7   3.7
 17000 -14.7   5.5  215  33 17   6.5   3.6 | -14.6   5.7  200  29 15   7.0   3.9
 16500 -13.8   7.2  215  34 17   6.5   3.6 | -13.5   7.7  200  30 15   7.2   4.0
 16000 -12.8   9.0  220  35 18   6.2   3.4 | -12.4   9.7  200  30 16   6.9   3.8
 15500 -12.1  10.2  220  34 18   4.8   2.6 | -11.6  11.1  200  31 16   4.7   2.6
 15000 -11.4  11.5  220  34 17   4.9   2.7 | -10.9  12.4  200  31 16   4.8   2.6
 14500 -10.7  12.7  220  33 17   4.1   2.3 | -10.2  13.6  200  30 16   4.9   2.7
 14000 -10.1  13.8  220  32 17   4.1   2.2 |  -9.5  14.9  205  30 15   4.8   2.6
 13500  -8.9  16.0  220  31 16   6.1   3.3 |  -8.3  17.1  205  29 15   5.6   3.1
 13000  -8.1  17.4  220  30 15   6.1   3.4 |  -7.5  18.5  205  28 15   5.6   3.1
 12500  -7.1  19.2  220  29 15   7.4   4.1 |  -6.8  19.8  205  28 14   4.7   2.6
 12000  -6.0  21.2  225  27 14   7.4   4.0 |  -6.1  21.0  205  27 14   4.8   2.6
 11500  -4.9  23.2  225  26 13   7.6   4.2 |  -5.3  22.5  200  26 13   6.6   3.6
 11000  -3.8  25.2  225  24 13   7.6   4.1 |  -4.3  24.3  200  25 13   6.4   3.5
 10500  -2.8  27.0  220  23 12   6.9   3.8 |  -3.2  26.2  200  24 12   8.4   4.6
 10250  -2.3  27.9  220  23 12   7.6   4.2 |  -2.6  27.3  200  23 12   9.5   5.2
 10000  -1.7  28.9  220  23 12   8.7   4.8 |  -1.8  28.8  195  22 11  11.1   6.1
  9750  -1.0  30.2  220  22 12   8.3   4.6 |  -1.1  30.0  195  21 11   9.0   4.9
  9500  -0.4  31.3  215  22 11   8.0   4.4 |  -0.5  31.1  195  21 11   7.6   4.2
  9250   0.2  32.4  215  22 11   8.0   4.4 |   0.1  32.2  195  20 10   8.0   4.4
  9000   0.8  33.4  210  22 11   7.5   4.1 |   0.6  33.1  195  20 10   6.6   3.6
  8750   1.3  34.3  210  21 11   7.8   4.3 |   1.1  34.0  190  19 10   6.1   3.3
  8500   1.9  35.4  205  21 11   8.2   4.5 |   1.6  34.9  190  19 10   6.8   3.7
  8250   2.5  36.5  205  21 11   8.3   4.5 |   2.1  35.8  190  18  9   6.2   3.4
  8000   3.2  37.8  200  21 11   8.1   4.4 |   2.6  36.7  185  18  9   7.9   4.3
  7750   3.7  38.7  195  21 11   6.5   3.5 |   3.2  37.8  180  16  8   7.3   4.0
  7500   4.1  39.4  190  21 11   6.0   3.3 |   3.6  38.5  180  15  8   5.3   2.9
  7250   4.6  40.3  185  21 11   5.1   2.8 |   4.0  39.2  175  14  7   5.9   3.2
  7000   4.8  40.6  180  20 10   2.2   1.2 |   4.5  40.1  175  12  6   6.6   3.6
  6750   4.9  40.8  175  19 10   0.7   0.4 |   5.0  41.0  170  11  6   8.0   4.4
  6500   5.0  41.0  170  18  9   1.5   0.8 |   5.6  42.1  170  11  5   7.9   4.3
  6250   5.0  41.0  165  17  9  -1.6  -0.9 |   6.2  43.2  170  10  5   9.5   5.2
  6000   4.7  40.5  155  14  7  -4.0  -2.2 |   7.0  44.6  170   9  5  11.0   6.1
  5750   4.5  40.1  150  11  6  -1.3  -0.7 |   7.7  45.9  170   9  5   9.5   5.2
  5500   4.4  39.9  130   7  4  -1.1  -0.6 |   8.4  47.1  170   8  4   9.5   5.2
  5250   4.3  39.7  125   6  3  -3.5  -1.9 |   9.2  48.6  170   8  4  11.5   6.3
  5000     M     M    M   M  M     M     M |     M     M    M   M  M     M     M

           02/18/2017 at 1400 MST          |       02/18/2017 at 1700 MST
                                           |
K index... +22.2  LI... +2.5               | K index... +20.0  LI... +1.7
CAPE... 0.0  CIN... M                      | CAPE... 0.0  CIN... -0.6
                                           |
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 -59.6 -75.3  220  37 19   4.2   2.3 | -59.3 -74.7  225  36 19   4.0   2.2
 45000 -53.4 -64.1  220  57 29   4.3   2.3 | -53.3 -63.9  220  54 28   4.3   2.4
 40000 -46.5 -51.7  215  66 34   4.3   2.4 | -46.1 -51.0  210  66 34   4.5   2.5
 38000 -46.6 -51.9  210  73 37  -5.1  -2.8 | -45.7 -50.3  205  72 37  -3.9  -2.1
 36000 -49.6 -57.3  205  84 43  -5.1  -2.8 | -48.0 -54.4  205  81 42  -3.9  -2.1
 34000 -52.4 -62.3  205  94 49   3.2   1.8 | -50.3 -58.5  200  89 46   0.8   0.5
 32000 -48.3 -54.9  205  89 46   6.8   3.7 | -47.6 -53.7  200  86 44   4.5   2.5
 30000 -44.2 -47.6  205  83 43   8.2   4.5 | -44.8 -48.6  200  82 42   6.5   3.6
 29000 -41.7 -43.1  205  73 38   8.3   4.5 | -42.6 -44.7  200  75 39   7.6   4.2
 28000 -38.6 -37.5  200  62 32   8.3   4.5 | -39.7 -39.5  200  67 35   7.6   4.2
 27000 -36.2 -33.2  195  53 27   8.3   4.5 | -37.5 -35.5  195  61 31   7.5   4.1
 26000 -33.8 -28.8  200  52 27   8.0   4.4 | -34.9 -30.8  195  56 29   9.1   5.0
 25000 -31.4 -24.5  200  52 27   8.0   4.4 | -32.2 -26.0  195  51 26   9.1   5.0
 24000 -29.0 -20.2  200  53 27   8.0   4.4 | -29.4 -20.9  195  46 24   9.3   5.1
 23000 -26.6 -15.9  200  53 27   8.1   4.4 | -27.2 -17.0  195  45 23   6.6   3.6
 22000 -24.2 -11.6  200  52 27   8.1   4.5 | -25.3 -13.5  195  46 24   6.6   3.6
 21000 -21.8  -7.2  200  51 26   7.9   4.4 | -23.4 -10.1  195  46 24   6.6   3.6
 20000 -19.8  -3.6  200  50 26   6.3   3.5 | -21.4  -6.5  195  45 23   6.7   3.7
 19500 -18.9  -2.0  195  49 25   6.4   3.5 | -20.4  -4.7  195  44 23   6.7   3.7
 19000 -18.0  -0.4  195  49 25   6.4   3.5 | -19.4  -2.9  195  44 22   6.7   3.7
 18500 -17.0   1.4  195  48 25   6.6   3.6 | -18.4  -1.1  195  43 22   6.7   3.7
 18000 -16.2   2.8  195  47 24   4.5   2.5 | -17.5   0.5  195  42 21   6.1   3.4
 17500 -15.5   4.1  195  46 24   4.7   2.6 | -16.6   2.1  195  40 20   6.2   3.4
 17000 -14.8   5.4  195  44 23   5.2   2.9 | -15.7   3.7  200  38 19   6.5   3.6
 16500 -14.0   6.8  195  43 22   5.8   3.2 | -14.7   5.5  200  37 19   6.9   3.8
 16000 -13.1   8.4  195  41 21   5.8   3.2 | -13.7   7.3  200  37 19   6.9   3.8
 15500 -12.3   9.9  195  40 20   6.0   3.3 | -12.7   9.1  200  36 19   5.9   3.2
 15000 -11.4  11.5  195  38 19   6.0   3.3 | -11.8  10.8  205  36 19   5.9   3.2
 14500 -10.5  13.1  195  36 19   6.8   3.7 | -10.9  12.4  205  35 18   7.1   3.9
 14000  -9.5  14.9  195  35 18   6.8   3.7 |  -9.9  14.2  205  33 17   7.1   3.9
 13500  -8.1  17.4  200  32 16   6.0   3.3 |  -8.4  16.9  205  31 16   6.4   3.5
 13000  -7.2  19.0  200  30 15   6.0   3.3 |  -7.4  18.7  210  31 16   6.4   3.5
 12500  -6.3  20.7  200  29 15   6.4   3.5 |  -6.4  20.5  210  31 16   7.4   4.1
 12000  -5.4  22.3  200  27 14   6.4   3.5 |  -5.3  22.5  205  31 16   7.4   4.0
 11500  -4.5  23.9  200  26 13   5.3   2.9 |  -4.2  24.4  205  30 16   6.9   3.8
 11000  -3.7  25.3  200  24 12   5.5   3.0 |  -3.2  26.2  205  30 15   6.9   3.8
 10500  -3.0  26.6  200  22 11   4.8   2.6 |  -2.2  28.0  200  29 15   7.4   4.1
 10250  -2.6  27.3  200  21 11   5.3   2.9 |  -1.6  29.1  200  28 14   7.4   4.1
 10000  -2.2  28.0  195  20 10   6.0   3.3 |  -1.1  30.0  200  27 14   7.5   4.1
  9750  -1.8  28.8  195  19 10   5.9   3.2 |  -0.6  30.9  200  26 13   6.9   3.8
  9500  -1.4  29.5  195  17  9   5.7   3.1 |  -0.1  31.8  200  25 13   6.4   3.5
  9250  -1.0  30.2  195  16  8   5.7   3.1 |   0.4  32.7  200  23 12   6.7   3.7
  9000  -0.6  30.9  195  15  7   4.8   2.6 |   0.8  33.4  195  22 11   5.6   3.1
  8750  -0.2  31.6  195  14  7   6.0   3.3 |   1.1  34.0  195  20 10   3.5   1.9
  8500   0.3  32.5  195  12  6   7.7   4.2 |   1.3  34.3  195  18  9   3.1   1.7
  8250   0.8  33.4  200  11  6   6.5   3.5 |   1.5  34.7  190  16  8   3.2   1.8
  8000   1.4  34.5  200  10  5   9.6   5.3 |   1.7  35.1  190  14  7   3.2   1.8
  7750   2.2  36.0  205   9  5  10.5   5.8 |   2.0  35.6  180  11  6   3.1   1.7
  7500   2.8  37.0  210   8  4   8.2   4.5 |   2.2  36.0  175   9  5   2.9   1.6
  7250   3.5  38.3  210   8  4   8.8   4.8 |   2.3  36.1  165   7  4   2.9   1.6
  7000   4.1  39.4  215   8  4   9.1   5.0 |   2.6  36.7  145   6  3   4.6   2.5
  6750   4.8  40.6  220   7  4   9.9   5.4 |   3.0  37.4  130   3  2   6.0   3.3
  6500   5.6  42.1  220   7  4  10.2   5.6 |   3.4  38.1  090   2  1   5.4   3.0
  6250   6.3  43.3  225   7  4   9.9   5.4 |   3.8  38.8  040   3  1   6.7   3.6
  6000   7.0  44.6  225   7  3   9.7   5.3 |   4.3  39.7  030   3  2   8.4   4.6
  5750   7.8  46.0  230   7  3   9.9   5.4 |   5.0  41.0  025   3  2   9.2   5.1
  5500   8.5  47.3  230   6  3  10.1   5.5 |   5.6  42.1  020   3  2   8.9   4.9
  5250   9.2  48.6  235   6  3  10.0   5.5 |   6.2  43.2  020   3  2   6.2   3.4
  5000     M     M    M   M  M     M     M |     M     M    M   M  M     M     M
________________________________________________________________________________

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

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

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

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

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

DEFINITIONS:

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

042613



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