Soaring Guidance
Issued by NWS Denver/Boulder, CO

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000
UXUS97 KBOU 131406
SRGBOU

Soaring Forecast
National Weather Service Denver/Boulder, Colorado
0806 MDT Friday, April 13, 2018

This forecast is for Friday, April 13, 2018:

If the trigger temperature of 41.9 F/5.5 C is reached...then
   Thermal Soaring Index....................... Poor
   Maximum rate of lift........................ 0 ft/min (0.0 m/s)
   Maximum height of thermals.................. 7177 ft MSL (1892 ft AGL)

Forecast maximum temperature................... 41.0 F/5.5 C
Time of trigger temperature.................... None
Time of overdevelopment........................ None
Middle/high clouds during soaring window....... Broken/overcast opaque middle
Surface winds during soaring window............ More than 30 mph
Height of the -3 thermal index................. 5287 ft MSL (2 ft AGL)
Thermal soaring outlook for Saturday 04/14..... Fair

Wave Soaring Index............................. Poor
Wave Soaring Index trend (to 1800 MDT)......... No change
Height of stable layer (12-18K ft MSL)......... 17350 ft MSL (12065 ft AGL)
Weak PVA/NVA (through 1800 MDT)................ Neither
Potential height of wave....................... 18089 ft MSL (12804 ft AGL)
Wave soaring outlook for Saturday 04/14........ Poor

Remarks... Scattered showers

Sunrise/Sunset.................... 06:24:23 / 19:35:29 MDT
Total possible sunshine........... 13 hr 11 min 5 sec (791 min 5 sec)
Altitude of sun at 12:59:56 MDT... 59.47 degrees

Upper air data from rawinsonde observation taken on 04/13/2018 at 0600 MDT

Freezing level.................. 6869 ft MSL (1584 ft AGL)
Convective condensation level... 11115 ft MSL (5830 ft AGL)
Lifted condensation level....... 10364 ft MSL (5078 ft AGL)
Lifted index.................... +8.9
K index......................... +25.0

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  -53.9 -65.0   230   22   11   3.3   1.8  118.5 245.3    63.5      M    M
 45000  -53.5 -64.3   230   40   20  -0.3  -0.2  104.2 219.5    57.7      M    M
 40000  -52.9 -63.2   225   51   26   2.3   1.3   91.4 196.5    52.2      M    M
 38000  -47.6 -53.7   200   62   32  29.5  16.2   64.0 147.2    39.5      M    M
 36000  -51.1 -60.0   200   57   29  -0.6  -0.3   50.1 122.2    31.0      M    M
 34000  -51.4 -60.5   190   51   26  -1.1  -0.6   41.3 106.3    25.6      M    M
 32000  -48.9 -56.0   185   48   25   5.3   2.9   36.5  97.7    22.8      M    M
 30000  -45.9 -50.6   190   56   29   2.2   1.2   31.7  89.1    19.9      M    M
 29000  -45.6 -50.1   185   43   22   0.6   0.3   30.1  86.1    18.8      M    M
 28000  -45.4 -49.7   180   33   17   0.6   0.3   29.3  84.7    18.3      M    M
 27000  -45.2 -49.4   180   32   16   0.6   0.3   28.5  83.4    17.8      M    M
 26000  -45.4 -49.7   175   30   16  -4.1  -2.3   27.4  81.3    17.0      M    M
 25000  -46.5 -51.7   175   29   15  -3.3  -1.8   24.9  76.8    15.1      M    M
 24000  -46.3 -51.3   170   28   14   1.5   0.8   24.1  75.4    14.6      M    M
 23000  -45.9 -50.6   170   27   14   1.5   0.8   23.7  74.7    14.4      M    M
 22000  -45.4 -49.7   165   26   13   1.5   0.8   23.4  74.0    14.1      M    M
 21000  -45.0 -49.0   185   21   11   1.5   0.8   22.9  73.3    13.8      M    M
 20000  -44.6 -48.3   210   20   10   1.5   0.8   22.6  72.6    13.6      M    M
 19500  -44.3 -47.7   215   17    9   1.5   0.8   22.4  72.2    13.4      M    M
 19000  -44.1 -47.4   225   14    7   1.5   0.8   22.2  71.9    13.3      M    M
 18500  -43.9 -47.0   230   12    6   1.5   0.9   21.9  71.5    13.2      M    M
 18000  -43.7 -46.7   245   10    5   2.4   1.3   21.7  71.1    13.0      M    M
 17500  -43.4 -46.1   265    8    4  14.8   8.1   21.5  70.7    12.9      M    M
 17000  -43.2 -45.8   290    8    4 187.1 102.6   21.3  70.4    12.7      M    M
 16500  -20.9  -5.6   315    9    4 -43.6 -23.9   13.6  56.5     7.4      M    M
 16000  -19.9  -3.8   335   10    5   2.7   1.5   13.1  55.5     7.0      M    M
 15500  -18.5  -1.3   340   14    7   6.4   3.5   12.2  53.9     6.2      M    M
 15000  -17.6   0.3   335   17    9   6.3   3.5   11.6  52.9     5.7      M    M
 14500  -16.7   1.9   335   20   10   6.3   3.5   11.1  52.0     5.3      M    M
 14000  -15.7   3.7   335   22   12   6.3   3.5   10.6  51.0     4.8      M    M
 13500  -14.8   5.4   340   25   13   6.3   3.5   10.0  49.9     4.3      M    M
 13000  -13.9   7.0   340   27   14   6.3   3.5    9.4  48.9     3.8      M    M
 12500  -12.9   8.8   345   30   15   6.3   3.5    8.8  47.9     3.3      M    M
 12000  -12.0  10.4   345   32   16   6.3   3.5    8.3  47.0     2.8      M    M
 11500  -11.1  12.0   345   30   15   6.3   3.5    7.7  45.8     2.2      M    M
 11000  -10.1  13.8   345   28   14   6.3   3.5    7.1  44.8     1.6      M    M
 10500   -9.2  15.4   345   26   13   6.4   3.5    6.5  43.8     1.1      M    M
 10250   -8.7  16.3   345   24   13   6.1   3.3    6.3  43.3     0.8      M    M
 10000   -8.3  17.1   345   23   12   7.5   4.1    6.0  42.8     0.6      M    M
  9750   -7.6  18.3   345   22   12   9.6   5.3    6.0  42.7     0.5      M    M
  9500   -6.9  19.6   345   23   12   9.5   5.2    5.9  42.7     0.5      M    M
  9250   -6.2  20.8   340   24   12   9.2   5.1    5.9  42.7     0.5      M    M
  9000   -5.5  22.1   340   25   13   9.3   5.1    5.9  42.6     0.5      M    M
  8750   -4.8  23.4   340   25   13   9.3   5.1    5.8  42.5     0.4      M    M
  8500   -4.1  24.6   335   25   13   9.3   5.1    5.8  42.5     0.4      M    M
  8250   -3.4  25.9   335   26   13   9.3   5.1    5.8  42.4     0.3      M    M
  8000   -2.7  27.1   335   26   13   9.2   5.1    5.8  42.4     0.3      M    M
  7750   -2.0  28.4   335   26   13   9.5   5.2    5.7  42.3     0.3      M    M
  7500   -1.3  29.7   335   26   13   8.6   4.7    5.7  42.2     0.2      M    M
  7250   -0.8  30.6   335   26   13   7.0   3.9    5.5  41.9     0.1      M    M
  7000   -0.3  31.5   335   26   13   6.8   3.7    5.3  41.5    -0.2     28  0.1
  6750    0.2  32.4   335   24   12   6.9   3.8    5.1  41.1    -0.4      5  0.0
  6500    0.7  33.3   335   22   11   6.9   3.8    4.8  40.7    -0.6      M    M
  6250    1.2  34.2   330   20   10   6.7   3.7    4.6  40.3    -0.9      M    M
  6000    1.7  35.1   330   18    9   7.4   4.1    4.4  40.0    -1.1      M    M
  5750    2.2  36.0   325   13    7   5.0   2.7    4.2  39.6    -1.3      M    M
  5500    2.3  36.1   310    8    4  -1.9  -1.0    3.6  38.5    -2.0      M    M

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

           04/13/2018 at 0900 MDT          |       04/13/2018 at 1200 MDT
                                           |
CAPE...    +2.2    LI...       +5.7        | CAPE...   +18.7    LI...       +3.9
CINH...    -1.5    K Index... +11.8        | CINH...    -0.2    K Index... +13.0
                                           |
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 -54.4 -65.9  190  48 25   2.3   1.3 | -53.5 -64.3  200  27 14   1.9   1.1
 45000 -50.8 -59.4  200  32 16   2.3   1.3 | -50.5 -58.9  185  46 24   1.9   1.1
 40000 -48.2 -54.8  190  55 28   1.7   0.9 | -48.8 -55.8  195  34 18   1.0   0.6
 38000 -47.3 -53.1  190  65 33  -0.7  -0.4 | -48.3 -54.9  195  30 15   0.0   0.0
 36000 -47.6 -53.7  185  68 35  -0.5  -0.3 | -48.2 -54.8  190  40 20   0.1   0.0
 34000 -48.0 -54.4  185  71 37  -0.5  -0.3 | -48.2 -54.8  185  50 26   0.1   0.0
 32000 -48.8 -55.8  180  66 34  -1.9  -1.0 | -49.1 -56.4  180  34 18  -2.1  -1.1
 30000 -50.1 -58.2  175  56 29  -2.0  -1.1 | -50.3 -58.5  155  10  5  -2.2  -1.2
 29000 -49.1 -56.4  175  47 24   6.7   3.7 | -49.3 -56.7  100   5  3   7.7   4.2
 28000 -47.1 -52.8  170  37 19   6.8   3.8 | -46.9 -52.4  050   7  4   7.9   4.3
 27000 -45.1 -49.2  160  26 13   6.8   3.8 | -44.6 -48.3  030  12  6   7.9   4.3
 26000 -42.9 -45.2  145  18  9   9.0   4.9 | -42.2 -44.0  025  16  8   8.1   4.4
 25000 -40.2 -40.4  135  15  8   9.1   5.0 | -39.8 -39.6  020  17  9   8.1   4.5
 24000 -37.5 -35.5  125  12  6   9.1   5.0 | -37.3 -35.1  020  18  9   8.1   4.5
 23000 -34.8 -30.6  115  10  5   8.0   4.4 | -34.9 -30.8  015  19 10   7.3   4.0
 22000 -32.5 -26.5  145  13  7   7.7   4.2 | -32.9 -27.2  015  18  9   7.0   3.8
 21000 -30.2 -22.4  160  18  9   7.7   4.2 | -30.8 -23.4  015  18  9   7.0   3.8
 20000 -28.0 -18.4  160  12  6   7.2   3.9 | -28.3 -18.9  010  18  9   6.3   3.4
 19500 -26.9 -16.4  055   4  2   7.2   4.0 | -27.4 -17.3  005  18  9   6.2   3.4
 19000 -25.8 -14.4  010  17  9   7.2   4.0 | -26.5 -15.7  005  18  9   6.2   3.4
 18500 -24.8 -12.6  005  31 16   7.2   4.0 | -25.5 -13.9  360  18  9   6.2   3.4
 18000 -23.7 -10.7  360  45 23   7.3   4.0 | -24.6 -12.3  360  18  9   5.7   3.1
 17500 -22.3  -8.1  360  33 17   6.2   3.4 | -23.8 -10.8  355  17  9   5.3   2.9
 17000 -21.3  -6.3  360  16  8   6.1   3.3 | -23.1  -9.6  350  16  8   5.3   2.9
 16500 -20.6  -5.1  355  12  6   4.4   2.4 | -22.3  -8.1  355  50 26   5.2   2.8
 16000 -19.9  -3.8  355  13  7   4.5   2.5 | -21.5  -6.7  355 100 51   5.1   2.8
 15500 -19.3  -2.7  350  14  7   4.1   2.3 | -20.7  -5.3  355 129 66   6.0   3.3
 15000 -18.7  -1.7  345  13  7   4.1   2.3 | -19.8  -3.6  355 126 65   6.0   3.3
 14500 -18.1  -0.6  350  22 11   4.2   2.3 | -18.9  -2.0  355 124 64   6.2   3.4
 14000 -17.5   0.5  355  76 39   4.2   2.3 | -18.0  -0.4  355 122 63   6.2   3.4
 13500 -16.8   1.8  355 128 66   5.3   2.9 | -17.1   1.2  355 120 62   6.4   3.5
 13000 -15.9   3.4  355 126 65   6.2   3.4 | -16.1   3.0  355 120 62   6.6   3.6
 12500 -15.0   5.0  355 125 64   7.3   4.0 | -15.2   4.6  355 119 61   6.8   3.7
 12000 -13.7   7.3  355 124 64   8.4   4.6 | -14.1   6.6  355 119 61   7.0   3.8
 11500 -12.4   9.7  355 124 64   8.1   4.5 | -13.1   8.4  355 119 61   7.5   4.1
 11000 -11.3  11.7  355 123 63   7.8   4.3 | -11.9  10.6  355 120 62   7.9   4.3
 10500 -10.1  13.8  355 122 63   7.4   4.1 | -10.8  12.6  355 120 62   8.1   4.4
 10250  -9.6  14.7  355 121 63   6.5   3.6 | -10.2  13.6  355 121 62   8.0   4.4
 10000  -9.1  15.6  355 121 62   8.5   4.7 |  -9.6  14.7  355 122 63   8.9   4.9
  9750  -8.4  16.9  355 119 61  10.4   5.7 |  -8.8  16.2  355 121 62  10.2   5.6
  9500  -7.6  18.3  355 116 60   9.2   5.1 |  -8.1  17.4  355 121 62  10.4   5.7
  9250  -7.0  19.4  355 114 59   9.3   5.1 |  -7.3  18.9  355 123 63  11.3   6.2
  9000  -6.3  20.7  355 112 58   8.3   4.5 |  -6.5  20.3  355 124 64   9.0   5.0
  8750  -5.7  21.7  355 110 57   7.6   4.2 |  -5.9  21.4  355 123 63   7.4   4.1
  8500  -5.1  22.8  355 109 56   8.8   4.8 |  -5.3  22.5  355 122 63   9.4   5.2
  8250  -4.4  24.1  355 107 55   9.2   5.1 |  -4.6  23.7  355 122 63   9.3   5.1
  8000  -3.7  25.3  355 105 54   8.8   4.8 |  -3.8  25.2  355 123 63  11.0   6.1
  7750  -3.1  26.4  355 101 52   8.9   4.9 |  -3.0  26.6  355 126 65  10.9   6.0
  7500  -2.4  27.7  355  99 51   9.3   5.1 |  -2.3  27.9  355 125 64   9.1   5.0
  7250  -1.7  28.9  355  98 51   9.3   5.1 |  -1.5  29.3  355 125 64   9.4   5.1
  7000  -1.0  30.2  355  97 50   8.9   4.9 |  -0.8  30.6  355 124 64  10.2   5.6
  6750  -0.4  31.3  355 100 51   9.4   5.1 |  -0.0  32.0  360 127 65  10.4   5.7
  6500   0.4  32.7  355  98 50  10.1   5.6 |   0.7  33.3  360 126 65   9.5   5.2
  6250   1.1  34.0  355  96 49  10.0   5.5 |   2.2  36.0  360 125 64  12.3   6.8
  6000   1.8  35.2  355  95 49  10.0   5.5 |   3.1  37.6  360 127 65  11.1   6.1
  5750   2.6  36.7  360  98 50  11.1   6.1 |   3.8  38.8  360 124 64   8.7   4.8
  5500   3.5  38.3  360  97 50  13.5   7.4 |   5.4  41.7  360 126 65  45.5  25.0

           04/13/2018 at 1500 MDT          |       04/13/2018 at 1800 MDT
                                           |
CAPE...   +16.6    LI...       +2.6        | CAPE...   +11.0    LI...       +3.2
CINH...    -0.2    K Index... +14.2        | CINH...    -1.1    K Index... +13.7
                                           |
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 -53.4 -64.1  335  21 11   1.7   0.9 | -53.6 -64.5  350  56 29   1.6   0.9
 45000 -50.8 -59.4  250   8  4   1.7   0.9 | -51.1 -60.0  355  63 32   1.6   0.9
 40000 -48.9 -56.0  345  25 13   1.2   0.7 | -49.3 -56.7  355  79 41   1.2   0.6
 38000 -48.3 -54.9  355  37 19  -1.0  -0.6 | -48.8 -55.8  355  87 45  -1.8  -1.0
 36000 -48.8 -55.8  355  46 24  -0.8  -0.5 | -49.7 -57.5  360 100 51  -1.4  -0.8
 34000 -49.3 -56.7  355  57 30  -0.8  -0.5 | -50.7 -59.3  360 114 59  -1.7  -0.9
 32000 -49.5 -57.1  360  43 22  -0.1  -0.1 | -49.9 -57.8  360  73 38   1.8   1.0
 30000 -49.5 -57.1  015  23 12  -0.5  -0.3 | -48.9 -56.0  010  20 10   1.3   0.7
 29000 -48.3 -54.9  020  19 10   6.9   3.8 | -47.4 -53.3  015  12  6   6.5   3.6
 28000 -46.2 -51.2  020  18  9   7.0   3.9 | -45.4 -49.7  010  11  6   6.5   3.6
 27000 -44.1 -47.4  015  18  9   7.0   3.9 | -43.4 -46.1  360  11  6   6.5   3.6
 26000 -41.9 -43.4  010  25 13   7.6   4.2 | -41.4 -42.5  355  21 11   7.6   4.2
 25000 -39.6 -39.3  005  60 31   7.6   4.2 | -39.2 -38.6  355  58 30   7.5   4.1
 24000 -37.4 -35.3  360  96 49   7.7   4.2 | -36.9 -34.4  360  95 49   7.5   4.1
 23000 -35.1 -31.2  360 121 62   6.8   3.7 | -34.8 -30.6  360 124 64   5.7   3.1
 22000 -33.1 -27.6  360  80 41   6.7   3.7 | -33.1 -27.6  360 126 65   5.8   3.2
 21000 -31.1 -24.0  360  40 21   6.7   3.7 | -31.3 -24.3  360 128 66   5.8   3.2
 20000 -29.2 -20.6  360  33 17   6.1   3.3 | -29.0 -20.2  360 129 67   6.6   3.6
 19500 -27.8 -18.0  360  69 36   6.1   3.3 | -28.0 -18.4  360 129 67   6.6   3.6
 19000 -26.9 -16.4  360  93 48   6.1   3.3 | -27.0 -16.6  360 130 67   6.7   3.7
 18500 -26.0 -14.8  360 116 60   6.1   3.3 | -26.0 -14.8  360 130 67   6.7   3.7
 18000 -25.1 -13.2  360 135 69   6.5   3.6 | -25.1 -13.2  360 130 67   6.5   3.6
 17500 -24.1 -11.4  360 133 69   6.6   3.6 | -24.1 -11.4  360 130 67   6.5   3.6
 17000 -23.1  -9.6  355 132 68   6.5   3.6 | -23.1  -9.6  355 130 67   6.5   3.6
 16500 -22.2  -8.0  355 130 67   6.3   3.5 | -22.2  -8.0  355 129 66   6.5   3.5
 16000 -21.2  -6.2  355 128 66   6.3   3.5 | -21.2  -6.2  355 128 66   6.4   3.5
 15500 -20.3  -4.5  355 126 65   6.3   3.5 | -20.3  -4.5  355 128 66   6.0   3.3
 15000 -19.4  -2.9  355 125 64   6.3   3.5 | -19.4  -2.9  355 128 66   6.0   3.3
 14500 -18.4  -1.1  355 124 64   6.8   3.7 | -18.5  -1.3  355 128 66   6.2   3.4
 14000 -17.4   0.7  355 124 64   6.9   3.8 | -17.6   0.3  355 128 66   6.2   3.4
 13500 -16.4   2.5  355 124 64   6.7   3.7 | -16.7   1.9  355 128 66   6.1   3.3
 13000 -15.4   4.3  355 124 64   6.7   3.7 | -15.8   3.6  355 129 66   6.1   3.3
 12500 -14.4   6.1  355 124 64   6.9   3.8 | -14.9   5.2  355 129 67   6.5   3.5
 12000 -13.4   7.9  355 125 64   6.9   3.8 | -13.9   7.0  355 130 67   6.4   3.5
 11500 -12.3   9.9  355 126 65   7.7   4.2 | -12.9   8.8  355 131 67   7.1   3.9
 11000 -11.2  11.8  355 127 65   7.9   4.4 | -11.9  10.6  355 132 68   7.1   3.9
 10500 -10.0  14.0  355 128 66   7.4   4.1 | -10.8  12.6  355 132 68   7.7   4.2
 10250  -9.5  14.9  355 128 66   6.7   3.7 | -10.2  13.6  355 133 68   7.7   4.2
 10000  -9.0  15.8  355 129 66   9.0   5.0 |  -9.7  14.5  355 133 68   7.6   4.2
  9750  -8.2  17.2  355 129 66  11.1   6.1 |  -9.1  15.6  355 133 69   8.0   4.4
  9500  -7.4  18.7  355 129 67   9.7   5.3 |  -8.5  16.7  360 134 69   8.4   4.6
  9250  -6.7  19.9  355 130 67  10.4   5.7 |  -7.9  17.8  360 134 69   8.1   4.5
  9000  -5.9  21.4  355 131 67   8.2   4.5 |  -7.3  18.9  360 134 69   8.8   4.8
  8750  -5.4  22.3  355 130 67   8.1   4.5 |  -6.6  20.1  360 135 69   8.8   4.8
  8500  -4.7  23.5  355 130 67  10.3   5.7 |  -6.0  21.2  360 135 69   8.3   4.6
  8250  -3.9  25.0  355 130 67   9.7   5.3 |  -5.3  22.5  360 134 69   8.1   4.4
  8000  -3.2  26.2  355 130 67   9.9   5.4 |  -4.7  23.5  360 134 69   9.5   5.2
  7750  -2.5  27.5  360 131 68   9.9   5.4 |  -4.0  24.8  360 134 69   9.8   5.4
  7500  -1.7  28.9  360 131 67   9.9   5.4 |  -3.3  26.1  360 134 69   8.5   4.6
  7250  -1.0  30.2  360 131 67  10.0   5.5 |  -2.7  27.1  360 134 69   9.2   5.1
  7000  -0.2  31.6  360 131 67   9.7   5.3 |  -1.9  28.6  360 134 69  10.9   6.0
  6750   0.5  32.9  360 132 68  10.0   5.5 |  -1.1  30.0  360 134 69  10.3   5.7
  6500   1.3  34.3  360 131 68  10.3   5.6 |  -0.4  31.3  360 133 69   8.9   4.9
  6250   2.0  35.6  360 131 67  10.6   5.8 |   0.3  32.5  360 126 65  10.2   5.6
  6000   2.9  37.2  360 131 67  12.2   6.7 |   1.1  34.0  360  70 36  11.7   6.4
  5750   3.8  38.8  360 131 67  10.4   5.7 |   2.0  35.6  360  14  7   9.4   5.1
  5500   4.5  40.1  360 129 67  10.1   5.6 |   2.6  36.7  360  11  6   8.4   4.6
________________________________________________________________________________

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 near the old Stapleton
Airport site in Denver, Colorado at

                   North Latitude:  39 deg 46 min 5.016 sec
                   West Longitude: 104 deg 52 min 9.984 sec
                   Elevation: 5285 feet (1611 meters)

and may not be representative of other areas along the Front Range of the
Colorado Rocky Mountains.  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.

CINH (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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