Soaring Guidance
Issued by NWS Grand Junction, CO

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000
UXUS97 KGJT 181247
SRGGJT

Soaring Forecast
National Weather Service Grand Junction, Colorado
0547 MST Sunday, February 18, 2018

This forecast is for Sunday, February 18, 2018:

If the trigger temperature of 54.8 F/12.7 C is reached...then
   Thermal Soaring Index....................... Good
   Maximum rate of lift........................ 469 ft/min (2.4 m/s)
   Maximum height of thermals.................. 10984 ft MSL (6145 ft AGL)

Forecast maximum temperature................... 58.0 F/14.9 C
Time of trigger temperature.................... 1245 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................. 7438 ft MSL (2598 ft AGL)
Thermal soaring outlook for Monday 02/19....... Good

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

Remarks...

Sunrise/Sunset.................... 07:01:35 / 17:53:38 MST
Total possible sunshine........... 10 hr 52 min 4 sec (652 min 4 sec)
Altitude of sun at 12:27:53 MST... 39.48 degrees

Upper air data from rawinsonde observation taken on 02/18/2018 at 0500 MST

Freezing level.................. 4863 ft MSL (24 ft AGL)
Additional freezing level....... 9146 ft MSL (4307 ft AGL)
Convective condensation level... 18694 ft MSL (13855 ft AGL)
Lifted condensation level....... 15090 ft MSL (10251 ft AGL)
Lifted index.................... +6.7
K index......................... +1.3

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  -64.4 -83.9   255   88   45   3.6   2.0   96.2 205.2    46.2      M    M
 45000  -65.1 -85.2   265   79   41   3.6   2.0   69.0 156.3    33.2      M    M
 40000  -63.0 -81.4   260   70   36   0.8   0.4   49.4 120.9    22.8      M    M
 38000  -60.3 -76.5   255   72   37   5.1   2.8   44.7 112.4    20.3      M    M
 36000  -56.2 -69.2   255   70   36   2.6   1.4   42.0 107.7    19.0      M    M
 34000  -53.2 -63.8   260   68   35   3.0   1.7   38.0 100.4    16.7      M    M
 32000  -49.6 -57.3   270   64   33   8.0   4.4   34.8  94.7    14.8      M    M
 30000  -45.7 -50.3   260   57   29   9.0   5.0   31.2  88.2    12.5      M    M
 29000  -43.0 -45.4   260   58   30   9.0   5.0   30.9  87.6    12.4      M    M
 28000  -40.3 -40.5   260   58   30   9.0   4.9   30.6  87.1    12.4      M    M
 27000  -37.7 -35.9   255   59   30   8.2   4.5   30.2  86.4    12.2      M    M
 26000  -35.3 -31.5   255   59   31   8.2   4.5   29.6  85.2    11.9      M    M
 25000  -32.8 -27.0   255   60   31   8.0   4.4   29.1  84.3    11.6      M    M
 24000  -30.6 -23.1   255   64   33   6.6   3.6   28.1  82.7    11.0      M    M
 23000  -28.6 -19.5   255   65   33   6.3   3.5   27.0  80.7    10.2      M    M
 22000  -26.1 -15.0   250   65   33   9.2   5.1   26.5  79.6     9.9      M    M
 21000  -23.4 -10.1   250   65   33   7.5   4.1   26.2  79.2     9.8      M    M
 20000  -21.3  -6.3   250   62   32   7.2   3.9   25.3  77.5     9.1      M    M
 19500  -20.3  -4.5   250   61   32   7.8   4.3   24.8  76.7     8.8      M    M
 19000  -18.9  -2.0   250   60   31   9.6   5.2   24.7  76.4     8.7      M    M
 18500  -17.5   0.5   250   59   31   9.5   5.2   24.7  76.4     8.7      M    M
 18000  -16.2   2.8   250   58   30   7.9   4.3   24.5  76.0     8.6      M    M
 17500  -15.3   4.5   245   56   29   4.4   2.4   23.8  74.9     8.1      M    M
 17000  -14.2   6.4   245   54   28   5.9   3.2   22.6  72.6     7.0      M    M
 16500  -13.2   8.2   240   52   27   6.2   3.4   22.0  71.7     6.6      M    M
 16000  -12.8   9.0   240   51   26   0.8   0.4   20.9  69.7     5.6      M    M
 15500  -12.1  10.2   250   49   25   8.1   4.4   20.1  68.2     4.9      M    M
 15000  -11.0  12.2   255   48   25   7.5   4.1   19.7  67.5     4.5      M    M
 14500   -9.9  14.2   250   46   23   7.4   4.1   19.3  66.8     4.2      M    M
 14000   -8.8  16.2   250   44   23   7.5   4.1   18.9  66.1     3.9      M    M
 13500   -7.6  18.3   250   45   23   8.0   4.4   18.6  65.5     3.6      M    M
 13000   -6.4  20.5   255   45   23   7.8   4.3   18.3  65.0     3.4      M    M
 12500   -5.2  22.6   255   46   23   7.6   4.2   18.0  64.4     3.1      M    M
 12000   -4.1  24.6   255   45   23   8.2   4.5   17.6  63.7     2.8      M    M
 11500   -3.4  25.9   245   38   19   0.2   0.1   16.8  62.3     2.1      M    M
 11000   -4.0  24.8   235   31   16  -0.4  -0.2   14.7  58.5    -0.0    469  2.4
 10500   -3.2  26.2   235   29   15   6.9   3.8   14.0  57.1    -0.7    431  2.2
 10250   -2.6  27.3   240   28   15  10.0   5.5   13.9  57.1    -0.8    403  2.0
 10000   -1.9  28.6   240   27   14   8.7   4.8   13.9  57.0    -0.8    375  1.9
  9750   -1.3  29.7   240   26   14   7.4   4.1   13.8  56.8    -0.9    350  1.8
  9500   -0.8  30.6   240   25   13   6.7   3.7   13.5  56.4    -1.1    327  1.7
  9250   -0.2  31.6   240   24   12   6.9   3.8   13.3  56.0    -1.3    304  1.5
  9000    0.3  32.5   240   23   12   6.9   3.8   13.1  55.6    -1.6    282  1.4
  8750    0.8  33.4   240   21   11   6.9   3.8   12.9  55.2    -1.8    259  1.3
  8500    1.3  34.3   240   18    9   6.9   3.8   12.7  54.8    -2.0    236  1.2
  8250    1.8  35.2   245   16    8   6.9   3.8   12.5  54.4    -2.2    214  1.1
  8000    2.3  36.1   245   13    7   6.9   3.8   12.2  54.0    -2.4    191  1.0
  7750    2.8  37.0   230   11    6   6.9   3.8   12.0  53.6    -2.7    168  0.9
  7500    3.3  37.9   205   11    5   6.9   3.8   11.8  53.2    -2.9    146  0.7
  7250    3.8  38.8   185   12    6   6.9   3.8   11.6  52.8    -3.1    123  0.6
  7000    4.3  39.7   170   14    7   6.8   3.7   11.4  52.4    -3.4    100  0.5
  6750    4.9  40.8   165   17    9   7.3   4.0   11.1  52.0    -3.6     78  0.4
  6500    5.4  41.7   165   20   10   5.5   3.0   10.9  51.6    -3.8     55  0.3
  6250    5.9  42.6   165   23   12  12.2   6.7   10.7  51.2    -4.1     32  0.2
  6000    6.4  43.5   165   25   13 -12.9  -7.1   10.5  50.8    -4.3      9  0.0
  5750    4.1  39.4   165   22   11 -32.8 -18.0    7.4  45.3    -7.4     72  0.4
  5500    2.6  36.7   160   16    8  -6.8  -3.7    5.2  41.3    -9.6    108  0.5
  5250    2.7  36.9   155   11    6   6.6   3.6    4.6  40.2   -10.2     98  0.5
  5000    2.8  37.0   140    6    3 -10.2  -5.6    3.9  39.1   -10.9     89  0.5

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

           02/18/2018 at 0800 MST          |       02/18/2018 at 1100 MST
                                           |
K index... +0.2  LI... +5.2                | K index... +7.8  LI... +4.9
CAPE... 0.0  CIN... 0.0                    | CAPE... 0.0  CIN... 0.0
                                           |
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 -64.1 -83.4  265  84 43   3.2   1.8 | -64.1 -83.4  260  84 43   3.7   2.0
 45000 -59.3 -74.7  265  85 44   3.1   1.7 | -58.6 -73.5  265  91 47   3.6   2.0
 40000 -61.5 -78.7  260  86 44  -2.0  -1.1 | -61.5 -78.7  260  90 47  -2.6  -1.4
 38000 -61.1 -78.0  260  84 43   5.7   3.1 | -61.5 -78.7  260  89 46   5.8   3.2
 36000 -57.7 -71.9  260  79 40   5.8   3.2 | -57.9 -72.2  255  86 44   5.9   3.2
 34000 -54.2 -65.6  260  73 38   6.6   3.6 | -54.4 -65.9  255  82 42   6.6   3.6
 32000 -49.7 -57.5  260  71 37   7.5   4.1 | -49.9 -57.8  255  79 41   7.6   4.2
 30000 -45.3 -49.5  260  70 36   7.3   4.0 | -45.3 -49.5  255  76 39   7.6   4.2
 29000 -43.1 -45.6  260  69 36   7.1   3.9 | -43.0 -45.4  255  75 39   7.6   4.1
 28000 -40.5 -40.9  260  69 35   7.1   3.9 | -40.2 -40.4  255  74 38   7.6   4.1
 27000 -38.4 -37.1  255  69 35   7.1   3.9 | -37.9 -36.2  255  72 37   7.6   4.2
 26000 -36.1 -33.0  255  68 35   7.9   4.3 | -35.7 -32.3  255  71 37   7.5   4.1
 25000 -33.7 -28.7  255  67 35   7.9   4.3 | -33.5 -28.3  255  70 36   7.5   4.1
 24000 -31.3 -24.3  255  66 34   7.9   4.3 | -31.2 -24.2  250  69 35   7.5   4.1
 23000 -29.0 -20.2  255  65 33   7.8   4.3 | -29.1 -20.4  250  67 34   7.1   3.9
 22000 -26.7 -16.1  255  62 32   7.8   4.3 | -26.9 -16.4  250  64 33   7.1   3.9
 21000 -24.4 -11.9  260  60 31   7.6   4.2 | -24.8 -12.6  250  62 32   7.1   3.9
 20000 -22.4  -8.3  260  58 30   6.4   3.5 | -22.8  -9.0  255  59 30   6.8   3.7
 19500 -21.4  -6.5  260  56 29   6.4   3.5 | -21.8  -7.2  255  58 30   6.8   3.7
 19000 -20.5  -4.9  255  55 28   6.4   3.5 | -20.7  -5.3  255  57 29   6.8   3.7
 18500 -19.5  -3.1  255  53 27   6.4   3.5 | -19.7  -3.5  255  55 28   6.8   3.7
 18000 -18.5  -1.3  255  52 27   7.1   3.9 | -18.7  -1.7  255  54 28   6.8   3.8
 17500 -17.5   0.5  255  50 26   7.0   3.8 | -17.7   0.1  255  53 27   6.9   3.8
 17000 -16.4   2.5  255  49 25   7.1   3.9 | -16.7   1.9  255  52 27   7.0   3.8
 16500 -15.3   4.5  255  48 25   7.1   3.9 | -15.6   3.9  255  50 26   7.1   3.9
 16000 -14.3   6.3  255  47 24   7.1   3.9 | -14.6   5.7  255  49 25   7.2   3.9
 15500 -13.2   8.2  250  46 24   7.1   3.9 | -13.5   7.7  255  47 24   7.4   4.0
 15000 -12.1  10.2  250  45 23   7.2   3.9 | -12.4   9.7  250  46 24   7.5   4.1
 14500 -11.1  12.0  250  44 23   6.8   3.7 | -11.4  11.5  250  45 23   6.3   3.4
 14000 -10.1  13.8  250  43 22   6.9   3.8 | -10.5  13.1  250  44 23   6.3   3.5
 13500  -8.6  16.5  250  42 22   6.5   3.6 |  -9.3  15.3  250  43 22   4.6   2.5
 13000  -7.7  18.1  245  41 21   6.5   3.6 |  -8.6  16.5  250  42 22   4.7   2.6
 12500  -6.7  19.9  245  41 21   6.0   3.3 |  -7.9  17.8  250  41 21   4.7   2.6
 12000  -5.9  21.4  245  41 21   6.1   3.3 |  -7.2  19.0  250  40 21   4.6   2.5
 11500  -5.0  23.0  245  41 21   5.7   3.1 |  -6.3  20.7  250  39 20   7.1   3.9
 11000  -4.1  24.6  245  41 21   5.8   3.2 |  -5.3  22.5  250  39 20   6.9   3.8
 10500  -3.2  26.2  245  41 21   6.5   3.6 |  -4.3  24.3  245  40 20   6.1   3.3
 10250  -2.7  27.1  245  42 21   7.3   4.0 |  -3.9  25.0  245  40 21   6.8   3.7
 10000  -2.1  28.2  245  42 21   9.1   5.0 |  -3.3  26.1  245  41 21   8.2   4.5
  9750  -1.4  29.5  245  42 21   8.2   4.5 |  -2.7  27.1  245  40 21   8.0   4.4
  9500  -0.9  30.4  240  41 21   7.2   4.0 |  -2.2  28.0  240  39 20   7.3   4.0
  9250  -0.4  31.3  240  40 21   7.6   4.2 |  -1.6  29.1  240  38 19   7.8   4.3
  9000   0.2  32.4  240  40 21   7.0   3.9 |  -1.1  30.0  235  37 19   5.6   3.1
  8750   0.7  33.3  240  39 20   6.4   3.5 |  -0.8  30.6  235  35 18   5.5   3.0
  8500   1.1  34.0  235  38 19   6.3   3.5 |  -0.3  31.5  235  31 16   7.3   4.0
  8250   1.6  34.9  235  37 19   6.6   3.6 |   0.2  32.4  230  28 15   7.0   3.8
  8000   2.1  35.8  230  35 18   6.2   3.4 |   0.7  33.3  225  25 13   6.6   3.6
  7750   2.4  36.3  225  34 17   3.4   1.9 |   1.2  34.2  225  23 12   6.8   3.7
  7500   2.6  36.7  225  32 17   2.1   1.1 |   1.8  35.2  225  20 10   7.3   4.0
  7250   2.8  37.0  220  31 16   2.0   1.1 |   2.3  36.1  220  18  9   7.8   4.3
  7000   2.9  37.2  215  29 15   0.2   0.1 |   2.9  37.2  220  17  9   9.7   5.3
  6750   2.8  37.0  205  27 14  -1.5  -0.8 |   3.7  38.7  220  16  8   9.9   5.5
  6500   2.7  36.9  200  24 12  -1.7  -1.0 |   4.4  39.9  220  15  8   9.4   5.2
  6250   2.5  36.5  190  22 11  -4.3  -2.4 |   5.1  41.2  220  14  7   9.9   5.4
  6000   2.0  35.6  185  19 10  -6.2  -3.4 |   5.9  42.6  215  13  7  10.3   5.6
  5750   1.6  34.9  175  15  8  -3.8  -2.1 |   6.6  43.9  215  13  6  10.0   5.5
  5500   1.4  34.5  165  11  6  -2.6  -1.4 |   7.4  45.3  215  11  6  10.3   5.7
  5250   1.2  34.2  165  10  5  -2.7  -1.5 |   8.2  46.8  220  11  6  11.6   6.3
  5000     M     M    M   M  M     M     M |     M     M    M   M  M     M     M

           02/18/2018 at 1400 MST          |       02/18/2018 at 1700 MST
                                           |
K index... +11.7  LI... +1.6               | K index... +16.7  LI... +0.5
CAPE... 0.0  CIN... -0.1                   | CAPE... +8.0  CIN... -1.8
                                           |
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 -64.1 -83.4  260  86 44   3.8   2.1 | -63.4 -82.1  260  93 48   3.5   1.9
 45000 -58.4 -73.1  260  94 48   3.7   2.0 | -58.2 -72.8  260  97 50   3.4   1.9
 40000 -60.1 -76.2  260  96 49  -1.8  -1.0 | -58.6 -73.5  255  98 50  -0.8  -0.4
 38000 -59.9 -75.8  255  96 49   5.3   2.9 | -58.5 -73.3  255  98 50   4.5   2.5
 36000 -56.7 -70.1  255  94 49   5.4   3.0 | -55.8 -68.4  250  98 50   4.1   2.2
 34000 -53.4 -64.1  250  93 48   6.0   3.3 | -53.3 -63.9  250  97 50   4.5   2.5
 32000 -49.2 -56.6  250  90 46   7.1   3.9 | -49.4 -56.9  250  92 47   6.7   3.7
 30000 -45.0 -49.0  250  88 45   7.3   4.0 | -45.4 -49.7  250  85 44   6.9   3.8
 29000 -42.7 -44.9  250  85 44   7.6   4.2 | -43.2 -45.8  250  84 43   7.4   4.1
 28000 -40.4 -40.7  250  83 43   7.6   4.2 | -41.0 -41.8  250  82 42   7.4   4.1
 27000 -38.1 -36.6  250  81 42   7.6   4.1 | -38.7 -37.7  250  81 42   7.4   4.0
 26000 -35.9 -32.6  250  78 40   6.9   3.8 | -36.6 -33.9  255  79 41   6.4   3.5
 25000 -33.9 -29.0  250  77 39   6.9   3.8 | -34.7 -30.5  255  78 40   6.5   3.6
 24000 -31.8 -25.2  250  75 38   6.9   3.8 | -32.8 -27.0  255  77 39   6.5   3.6
 23000 -29.7 -21.5  250  72 37   6.7   3.7 | -30.8 -23.4  255  75 39   7.1   3.9
 22000 -27.2 -17.0  250  68 35   6.7   3.7 | -28.7 -19.7  255  72 37   7.1   3.9
 21000 -25.2 -13.4  250  65 33   6.8   3.7 | -26.5 -15.7  255  69 36   7.1   3.9
 20000 -23.2  -9.8  250  62 32   6.9   3.8 | -23.9 -11.0  255  65 34   6.9   3.8
 19500 -22.2  -8.0  250  60 31   6.9   3.8 | -22.9  -9.2  255  64 33   6.9   3.8
 19000 -21.1  -6.0  250  59 30   6.9   3.8 | -21.9  -7.4  255  62 32   6.9   3.8
 18500 -20.1  -4.2  250  57 30   6.9   3.8 | -20.9  -5.6  250  60 31   6.9   3.8
 18000 -19.1  -2.4  250  56 29   6.6   3.6 | -19.8  -3.6  250  58 30   6.9   3.8
 17500 -18.1  -0.6  245  55 28   6.7   3.7 | -18.8  -1.8  250  56 29   6.9   3.8
 17000 -17.1   1.2  245  53 27   6.7   3.7 | -17.8  -0.0  250  54 28   6.9   3.8
 16500 -16.1   3.0  245  52 27   6.7   3.7 | -16.8   1.8  250  52 27   7.0   3.8
 16000 -15.1   4.8  245  51 26   6.6   3.6 | -15.7   3.7  250  50 26   7.0   3.8
 15500 -14.2   6.4  245  50 26   6.2   3.4 | -14.7   5.5  250  48 25   7.2   3.9
 15000 -13.3   8.1  240  48 25   6.3   3.4 | -13.6   7.5  250  46 24   7.2   4.0
 14500 -12.4   9.7  240  47 24   6.1   3.4 | -12.6   9.3  250  44 23   6.6   3.6
 14000 -11.5  11.3  240  45 23   6.1   3.4 | -11.7  10.9  245  44 22   6.5   3.6
 13500 -10.5  13.1  240  43 22   6.5   3.5 | -10.7  12.7  245  43 22   7.1   3.9
 13000  -9.6  14.7  245  42 21   6.5   3.6 |  -9.6  14.7  240  43 22   7.4   4.0
 12500  -8.6  16.5  240  40 21   7.1   3.9 |  -8.6  16.5  240  44 23   8.2   4.5
 12000  -7.6  18.3  240  38 20   7.2   3.9 |  -7.3  18.9  235  43 22   8.7   4.8
 11500  -6.5  20.3  240  36 19   8.4   4.6 |  -6.0  21.2  235  43 22   8.6   4.7
 11000  -5.2  22.6  235  34 18   8.9   4.9 |  -4.8  23.4  230  42 22   8.6   4.7
 10500  -3.9  25.0  230  32 17   8.7   4.8 |  -3.5  25.7  225  41 21   9.3   5.1
 10250  -3.3  26.1  230  30 16   8.6   4.7 |  -2.8  27.0  225  40 21   9.7   5.3
 10000  -2.6  27.3  230  29 15   8.3   4.5 |  -2.1  28.2  225  40 20   8.5   4.6
  9750  -2.0  28.4  225  28 14   8.7   4.8 |  -1.5  29.3  225  39 20   8.2   4.5
  9500  -1.4  29.5  225  27 14   9.7   5.3 |  -0.9  30.4  225  38 20   9.2   5.0
  9250  -0.6  30.9  225  26 14  10.5   5.7 |  -0.1  31.8  220  37 19  10.2   5.6
  9000   0.1  32.2  225  25 13   8.4   4.6 |   0.6  33.1  220  36 19   8.5   4.7
  8750   0.7  33.3  225  25 13   8.4   4.6 |   1.2  34.2  220  36 18   7.7   4.2
  8500   1.4  34.5  225  24 12  10.6   5.8 |   1.8  35.2  220  35 18   9.3   5.1
  8250   2.2  36.0  225  23 12  11.0   6.0 |   2.5  36.5  220  34 17  10.3   5.6
  8000   3.0  37.4  225  23 12   8.8   4.8 |   3.3  37.9  220  32 17   8.3   4.5
  7750   3.6  38.5  225  22 12   8.4   4.6 |   3.8  38.8  220  32 16   7.2   4.0
  7500   4.3  39.7  225  22 11  10.3   5.7 |   4.4  39.9  220  30 16   8.9   4.9
  7250   5.1  41.2  225  21 11   9.9   5.4 |   5.1  41.2  220  29 15   8.7   4.8
  7000   5.8  42.4  225  21 11   9.8   5.4 |   5.7  42.3  215  28 14   9.4   5.1
  6750   6.5  43.7  225  20 10   9.9   5.4 |   6.4  43.5  215  26 14   9.1   5.0
  6500   7.3  45.1  225  20 10  10.1   5.6 |   7.1  44.8  215  24 12   8.3   4.6
  6250   8.0  46.4  225  19 10  10.3   5.7 |   7.7  45.9  215  22 11   8.6   4.7
  6000   8.8  47.8  225  18  9   9.4   5.2 |   8.3  46.9  215  20 10   8.3   4.5
  5750   9.6  49.3  225  17  9  13.9   7.6 |   8.9  48.0  215  19 10   8.1   4.5
  5500  11.0  51.8  225  16  8  23.9  13.1 |   9.5  49.1  215  17  9   8.7   4.8
  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
________________________________________________________________________________

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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