Soaring Guidance
Issued by NWS Denver/Boulder, CO

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000
UXUS97 KBOU 291232
SRGBOU

Soaring Forecast
National Weather Service Denver/Boulder, Colorado
0632 MDT Saturday, April 29, 2017

This forecast is for Saturday, April 29, 2017:

If the trigger temperature of 35.9 F/2.2 C is reached...then
   Thermal Soaring Index....................... Poor
   Maximum rate of lift........................ 0 ft/min (0.0 m/s)
   Maximum height of thermals.................. 9328 ft MSL (4043 ft AGL)

Forecast maximum temperature................... 36.0 F/2.7 C
Time of trigger temperature.................... 1300 MDT
Time of overdevelopment........................ 1300 MDT
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................. 6087 ft MSL (802 ft AGL)
Thermal soaring outlook for Sunday 04/30....... Fair

Wave Soaring Index............................. Poor
Wave Soaring Index trend (to 1800 MDT)......... No change
Height of stable layer (12-18K ft MSL)......... 14871 ft MSL (9586 ft AGL)
Weak PVA/NVA (through 1800 MDT)................ Neither
Potential height of wave....................... 15363 ft MSL (10078 ft AGL)
Wave soaring outlook for Sunday 04/30.......... Poor

Remarks... Strong spring storm centered over southeast colorado today. Cold
           temperatures and upslope snow continuing today.

Sunrise/Sunset.................... 06:01:46 / 19:51:46 MDT
Total possible sunshine........... 13 hr 50 min 0 sec (830 min 0 sec)
Altitude of sun at 12:56:46 MDT... 64.91 degrees

Upper air data from rawinsonde observation taken on 04/29/2017 at 0600 MDT

Freezing level.................. Entire airmass below 32 F / 0 C
Convective condensation level... 8595 ft MSL (3310 ft AGL)
Lifted condensation level....... 8983 ft MSL (3697 ft AGL)
Lifted index.................... +12.4
K index......................... +4.7

Height  Temperature  Wind  Wind Spd  Lapse Rate  ConvectionT  Thermal  Lift Rate
ft MSL  deg C deg F   Dir   kt  m/s  C/km F/kft  deg C deg F   Index    fpm  m/s
--------------------------------------------------------------------------------
 50000  -55.4 -67.7   230   30   15   1.7   0.9  109.5 229.1    61.0      M    M
 45000  -52.9 -63.2   200   28   14   1.7   0.9   88.7 191.6    52.6      M    M
 40000  -51.4 -60.5   205   39   20  -0.2  -0.1   66.7 152.0    42.1      M    M
 38000  -52.3 -62.1   200   48   25  -4.3  -2.3   56.6 133.8    36.4      M    M
 36000  -54.3 -65.7   195   69   36  -0.0  -0.0   45.1 113.2    29.5      M    M
 34000  -54.3 -65.7   195   96   49  -0.2  -0.1   36.8  98.2    24.4      M    M
 32000  -51.1 -60.0   190  115   59   7.8   4.3   33.2  91.7    22.4      M    M
 30000  -46.4 -51.5   190  104   53   7.8   4.3   31.5  88.6    21.8      M    M
 29000  -43.4 -46.1   190   98   51   7.9   4.3   30.3  86.5    21.2      M    M
 28000  -41.1 -42.0   190   94   48   7.9   4.4   29.5  85.0    20.9      M    M
 27000  -38.7 -37.7   195   90   46   7.9   4.4   28.8  83.8    20.6      M    M
 26000  -36.3 -33.3   195   86   44   7.9   4.4   28.3  82.9    20.4      M    M
 25000  -34.0 -29.2   195   82   42   8.5   4.7   27.8  82.1    20.3      M    M
 24000  -32.6 -26.7   200   77   40   3.2   1.8   25.9  78.6    19.0      M    M
 23000  -32.3 -26.1   200   56   29   2.9   1.6   22.6  72.7    16.6      M    M
 22000  -30.2 -22.4   210   38   20   7.1   3.9   21.7  71.0    16.0      M    M
 21000  -28.1 -18.6   205   32   17   7.1   3.9   20.7  69.2    15.3      M    M
 20000  -26.0 -14.8   200   27   14   7.1   3.9   19.8  67.6    14.7      M    M
 19500  -24.9 -12.8   195   24   13   7.1   3.9   19.3  66.7    14.4      M    M
 19000  -23.8 -10.8   190   22   11   7.1   3.9   18.8  65.8    14.0      M    M
 18500  -22.8  -9.0   180   19   10   7.2   4.0   18.3  64.9    13.7      M    M
 18000  -21.8  -7.2   180   19   10   6.3   3.4   17.8  64.1    13.3      M    M
 17500  -20.8  -5.4   160   17    9   6.2   3.4   17.2  63.0    12.9      M    M
 17000  -19.9  -3.8   140   18    9   6.3   3.4   16.6  61.9    12.4      M    M
 16500  -19.0  -2.2   125   18    9   6.3   3.4   16.0  60.8    11.9      M    M
 16000  -18.1  -0.6   110   19   10   6.3   3.5   15.4  59.8    11.5      M    M
 15500  -17.2   1.0   100   20   10   7.1   3.9   14.8  58.7    11.0      M    M
 15000  -16.8   1.8   085   22   12  -4.7  -2.6   13.6  56.5    10.0      M    M
 14500  -17.7   0.1   080   21   11   1.6   0.9   10.0  50.1     6.9      M    M
 14000  -16.0   3.2   070   19   10  12.3   6.7   10.5  50.8     7.3      M    M
 13500  -16.4   2.5   050   18    9  -5.9  -3.3    8.4  47.1     5.4      M    M
 13000  -16.1   3.0   030   19   10   6.7   3.7    7.1  44.8     4.3      M    M
 12500  -15.2   4.6   015   19   10   5.9   3.2    6.5  43.7     3.7      M    M
 12000  -14.4   6.1   005   20   10   5.9   3.2    5.9  42.6     3.1      M    M
 11500  -13.5   7.7   005   19   10   5.9   3.2    5.2  41.4     2.5      M    M
 11000  -12.7   9.1   005   17    9   5.9   3.2    4.6  40.2     1.9      M    M
 10500  -11.8  10.8   005   16    8   5.9   3.2    4.0  39.1     1.3      M    M
 10250  -11.4  11.5   005   16    8   5.9   3.2    3.7  38.6     1.1      M    M
 10000  -10.9  12.4   005   16    8   5.8   3.2    3.4  38.1     0.8      M    M
  9750  -10.5  13.1   005   16    8   5.8   3.2    3.1  37.5     0.5      M    M
  9500  -10.1  13.8   010   15    8   5.8   3.2    2.8  37.0     0.2      M    M
  9250   -9.7  14.5   010   15    8   5.8   3.2    2.5  36.4    -0.1    273  1.4
  9000   -9.2  15.4   015   14    7   5.8   3.2    2.2  35.9    -0.4    253  1.3
  8750   -8.8  16.2   020   14    7   5.8   3.2    1.9  35.3    -0.7    233  1.2
  8500   -8.4  16.9   025   14    7   5.8   3.2    1.5  34.8    -1.1    213  1.1
  8250   -8.0  17.6   025   15    8   5.9   3.2    1.2  34.2    -1.4    192  1.0
  8000   -7.5  18.5   030   15    8   5.6   3.1    1.0  33.7    -1.7    172  0.9
  7750   -7.1  19.2   030   16    8   6.9   3.8    0.6  33.2    -2.0    152  0.8
  7500   -6.5  20.3   030   17    8   8.3   4.5    0.5  32.9    -2.1    127  0.6
  7250   -5.9  21.4   030   17    9   7.9   4.3    0.4  32.7    -2.3    102  0.5
  7000   -5.4  22.3   030   18    9   8.0   4.4    0.3  32.5    -2.4     78  0.4
  6750   -4.8  23.4   030   18    9   8.0   4.4    0.1  32.2    -2.6     53  0.3
  6500   -4.2  24.4   030   18   10   8.0   4.4   -0.0  32.0    -2.7     28  0.1
  6250   -3.6  25.5   025   19   10   8.0   4.4   -0.1  31.7    -2.9      3  0.0
  6000   -3.0  26.6   025   19   10   8.0   4.4   -0.3  31.5    -3.0      M    M
  5750   -2.5  27.5   020   16    8   8.0   4.4   -0.4  31.3    -3.2      M    M
  5500   -1.9  28.6   005   12    6   8.0   4.4   -0.5  31.0    -3.4      M    M

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

           04/29/2017 at 0900 MDT          |       04/29/2017 at 1200 MDT
                                           |
CAPE...   +27.8    LI...       +8.9        | CAPE...   +50.9    LI...       +8.4
CINH...    -0.1    K Index...  +6.8        | CINH...     0.0    K Index...  +7.7
                                           |
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 -54.3 -65.7  230   8  4   1.1   0.6 | -54.3 -65.7  215   7  4   1.4   0.7
 45000 -52.6 -62.7  200  12  6   1.1   0.6 | -52.3 -62.1  200  11  6   1.3   0.7
 40000 -51.6 -60.9  190  17  9   0.6   0.4 | -51.0 -59.8  180  15  8   0.9   0.5
 38000 -51.4 -60.5  185  21 11  -0.7  -0.4 | -50.7 -59.3  175  17  9  -0.3  -0.2
 36000 -51.9 -61.4  180  29 15  -0.7  -0.4 | -50.9 -59.6  175  22 12  -0.3  -0.2
 34000 -52.3 -62.1  180  38 19  -1.1  -0.6 | -51.1 -60.0  175  28 14   1.4   0.7
 32000 -49.5 -57.1  175  39 20   4.7   2.6 | -49.3 -56.7  175  30 15   2.9   1.6
 30000 -46.7 -52.1  175  38 20   7.0   3.9 | -47.5 -53.5  170  32 16   6.5   3.6
 29000 -44.2 -47.6  175  36 19   8.1   4.4 | -45.1 -49.2  170  29 15   8.2   4.5
 28000 -41.8 -43.2  175  34 18   8.1   4.4 | -42.6 -44.7  170  27 14   8.2   4.5
 27000 -39.4 -38.9  175  32 17   8.2   4.5 | -40.1 -40.2  165  25 13   8.3   4.5
 26000 -37.4 -35.3  180  29 15   5.9   3.2 | -37.9 -36.2  165  22 11   6.9   3.8
 25000 -35.6 -32.1  185  25 13   5.8   3.2 | -35.9 -32.6  165  18  9   6.9   3.8
 24000 -33.9 -29.0  190  22 11   5.8   3.2 | -33.8 -28.8  170  15  8   6.9   3.8
 23000 -32.1 -25.8  195  18  9   6.1   3.4 | -31.8 -25.2  165  12  6   6.6   3.6
 22000 -30.3 -22.5  195  13  7   6.1   3.4 | -29.8 -21.6  160   9  5   6.6   3.6
 21000 -28.5 -19.3  195   9  4   6.0   3.3 | -27.8 -18.0  150   6  3   6.6   3.6
 20000 -26.4 -15.5  180   6  3   7.3   4.0 | -25.8 -14.4  120   6  3   7.0   3.8
 19500 -25.3 -13.5  165   5  2   7.3   4.0 | -24.7 -12.5  105   6  3   7.0   3.9
 19000 -24.3 -11.7  145   4  2   7.3   4.0 | -23.7 -10.7  095   7  4   7.0   3.9
 18500 -22.7  -8.9  115   5  2   6.9   3.8 | -22.1  -7.8  085   8  4   7.0   3.9
 18000 -21.7  -7.1  105   6  3   5.8   3.2 | -21.1  -6.0  085   9  5   7.1   3.9
 17500 -20.9  -5.6  100   7  3   5.8   3.2 | -20.0  -4.0  085   9  5   7.1   3.9
 17000 -20.0  -4.0  095   7  4   5.5   3.0 | -19.0  -2.2  090  10  5   6.5   3.6
 16500 -19.2  -2.6  095   8  4   5.5   3.0 | -18.0  -0.4  090  10  5   6.6   3.6
 16000 -18.5  -1.3  090   9  4   4.4   2.4 | -17.1   1.2  090  11  5   5.6   3.1
 15500 -17.9  -0.2  085   9  5   3.6   2.0 | -16.3   2.7  090  10  5   5.0   2.7
 15000 -17.4   0.7  080  10  5   2.6   1.4 | -15.6   3.9  090  10  5   3.5   1.9
 14500 -17.2   1.0  075  10  5   0.4   0.2 | -15.4   4.3  085  10  5   1.1   0.6
 14000 -17.2   1.0  065  10  5   0.9   0.5 | -15.2   4.6  075   9  5   1.3   0.7
 13500 -16.8   1.8  060  10  5   3.7   2.0 | -15.0   5.0  070   9  5   2.0   1.1
 13000 -16.3   2.7  060  11  6   3.6   2.0 | -14.7   5.5  060   9  4   2.0   1.1
 12500 -15.6   3.9  055  11  5   4.8   2.6 | -14.3   6.3  055   9  4   2.4   1.3
 12000 -14.9   5.2  050  11  5   4.7   2.6 | -14.0   6.8  045   9  4   2.6   1.4
 11500 -14.3   6.3  045  10  5   4.5   2.5 | -13.5   7.7  035   9  4   4.0   2.2
 11000 -13.6   7.5  040  10  5   4.7   2.6 | -12.9   8.8  030   9  5   4.2   2.3
 10500 -12.8   9.0  035  10  5   5.4   3.0 | -12.2  10.0  025   9  5   5.1   2.8
 10250 -12.4   9.7  030   9  5   4.8   2.6 | -11.8  10.8  020   9  5   5.0   2.8
 10000 -12.1  10.2  030   9  5   7.2   3.9 | -11.4  11.5  020   9  5   5.2   2.9
  9750 -11.4  11.5  030   9  5   7.7   4.2 | -11.0  12.2  020  10  5   6.0   3.3
  9500 -11.0  12.2  030   9  5   5.6   3.1 | -10.6  12.9  015  10  5   6.4   3.5
  9250 -10.6  12.9  030   9  5   6.2   3.4 | -10.1  13.8  015  10  5   6.4   3.5
  9000 -10.1  13.8  030   9  5   6.1   3.3 |  -9.6  14.7  015  10  5   6.1   3.3
  8750  -9.7  14.5  030   9  5   6.4   3.5 |  -9.2  15.4  015  10  5   6.9   3.8
  8500  -9.2  15.4  030   9  5   6.6   3.6 |  -8.6  16.5  015  11  5   7.9   4.3
  8250  -8.7  16.3  030   9  5   6.8   3.7 |  -8.1  17.4  015  11  6   7.5   4.1
  8000  -8.2  17.2  025   9  5   7.2   4.0 |  -7.5  18.5  010  11  6   7.5   4.1
  7750  -7.7  18.1  025   9  5   6.7   3.7 |  -7.0  19.4  010  11  6   7.2   4.0
  7500  -7.2  19.0  020   9  5   6.3   3.5 |  -6.5  20.3  005  11  5   7.2   4.0
  7250  -6.7  19.9  020   9  5   7.1   3.9 |  -5.9  21.4  005  10  5   8.0   4.4
  7000  -6.2  20.8  015   9  5   8.0   4.4 |  -5.3  22.5  005  10  5   8.7   4.8
  6750  -5.6  21.9  010   9  5   6.2   3.4 |  -4.7  23.5  360  10  5   7.5   4.1
  6500  -5.2  22.6  005   8  4   6.8   3.7 |  -4.2  24.4  360   9  5   7.8   4.3
  6250  -4.6  23.7  360   8  4   9.0   4.9 |  -3.5  25.7  355   9  5   9.3   5.1
  6000  -4.0  24.8  355   7  4   8.1   4.5 |  -2.9  26.8  355   9  4   8.2   4.5
  5750  -3.3  26.1  350   7  4   9.4   5.2 |  -2.2  28.0  355   8  4  10.9   6.0
  5500  -2.5  27.5  350   6  3  12.5   6.9 |  -1.2  29.8  355   7  4  17.5   9.6

           04/29/2017 at 1500 MDT          |       04/29/2017 at 1800 MDT
                                           |
CAPE...   +38.1    LI...       +8.8        | CAPE...   +16.0    LI...       +9.4
CINH...     0.0    K Index...  +8.2        | CINH...    -0.5    K Index...  +8.7
                                           |
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 -54.6 -66.3  215   7  4   1.5   0.9 | -54.9 -66.8  230   7  3   1.8   1.0
 45000 -52.3 -62.1  205   9  5   1.5   0.8 | -52.3 -62.1  235   6  3   1.6   0.9
 40000 -50.8 -59.4  180  12  6   0.9   0.5 | -50.8 -59.4  190   8  4   1.0   0.5
 38000 -50.6 -59.1  170  14  7  -0.9  -0.5 | -50.6 -59.1  180   8  4  -0.9  -0.5
 36000 -51.2 -60.2  170  16  8  -0.9  -0.5 | -51.3 -60.3  160   8  4  -0.9  -0.5
 34000 -51.8 -61.2  170  18  9   1.4   0.8 | -51.8 -61.2  145   8  4   1.8   1.0
 32000 -49.8 -57.6  165  19 10   3.3   1.8 | -49.7 -57.5  135  10  5   3.5   1.9
 30000 -47.7 -53.9  160  20 10   7.4   4.1 | -47.5 -53.5  130  12  6   7.4   4.1
 29000 -45.0 -49.0  155  19 10   8.8   4.8 | -44.9 -48.8  130  12  6   8.5   4.6
 28000 -42.4 -44.3  150  18  9   8.8   4.8 | -42.4 -44.3  125  12  6   8.5   4.7
 27000 -39.8 -39.6  145  17  9   8.9   4.9 | -39.9 -39.8  125  12  6   8.6   4.7
 26000 -37.5 -35.5  145  15  8   6.7   3.7 | -37.6 -35.7  120  11  6   7.1   3.9
 25000 -35.5 -31.9  140  12  6   6.7   3.7 | -35.5 -31.9  105  10  5   7.1   3.9
 24000 -33.5 -28.3  135   9  5   6.7   3.7 | -33.3 -27.9  090   9  5   7.1   3.9
 23000 -31.5 -24.7  125   7  4   7.2   4.0 | -31.2 -24.2  075   9  5   7.3   4.0
 22000 -29.3 -20.7  110   6  3   7.2   4.0 | -29.0 -20.2  065   9  5   7.4   4.0
 21000 -27.2 -17.0  090   6  3   7.3   4.0 | -26.8 -16.2  055   9  5   7.4   4.1
 20000 -25.0 -13.0  080   7  4   7.1   3.9 | -24.6 -12.3  050  10  5   7.3   4.0
 19500 -24.0 -11.2  075   8  4   7.1   3.9 | -23.0  -9.4  045  10  5   7.3   4.0
 19000 -22.9  -9.2  075   9  4   7.1   3.9 | -21.9  -7.4  045  11  5   7.3   4.0
 18500 -21.3  -6.3  070  10  5   7.4   4.0 | -20.8  -5.4  045  11  6   7.1   3.9
 18000 -20.2  -4.4  075  10  5   7.8   4.3 | -19.8  -3.6  045  11  6   6.7   3.7
 17500 -19.0  -2.2  075  11  6   8.0   4.4 | -18.8  -1.8  045  11  6   7.0   3.9
 17000 -18.0  -0.4  075  11  6   5.8   3.2 | -18.0  -0.4  045  11  6   4.1   2.2
 16500 -17.1   1.2  075  11  5   6.1   3.3 | -17.4   0.7  040  11  6   4.3   2.4
 16000 -16.3   2.7  070  10  5   4.5   2.5 | -16.7   1.9  035  11  6   4.1   2.2
 15500 -15.7   3.7  065  10  5   3.8   2.1 | -16.2   2.8  030  11  6   3.9   2.2
 15000 -15.2   4.6  065  10  5   3.0   1.6 | -15.6   3.9  020  11  6   3.5   1.9
 14500 -14.9   5.2  055  10  5   1.8   1.0 | -15.2   4.6  015  11  6   2.8   1.5
 14000 -14.6   5.7  045  10  5   1.9   1.0 | -14.8   5.4  010  12  6   2.9   1.6
 13500 -14.3   6.3  035  10  5   2.4   1.3 | -14.3   6.3  005  13  6   3.3   1.8
 13000 -13.9   7.0  025  10  5   2.5   1.4 | -13.8   7.2  005  13  7   3.1   1.7
 12500 -13.5   7.7  020  10  5   2.9   1.6 | -13.4   7.9  005  13  7   2.0   1.1
 12000 -13.1   8.4  015  11  6   2.7   1.5 | -13.1   8.4  005  13  7   2.0   1.1
 11500 -12.8   9.0  010  11  6   2.1   1.2 | -12.9   8.8  005  13  7   1.7   0.9
 11000 -12.4   9.7  005  11  6   2.6   1.4 | -12.6   9.3  005  13  7   2.9   1.6
 10500 -11.9  10.6  005  11  6   4.0   2.2 | -11.8  10.8  005  13  7   6.4   3.5
 10250 -11.6  11.1  005  12  6   3.4   1.9 | -11.4  11.5  010  13  7   6.0   3.3
 10000 -11.4  11.5  005  12  6   5.4   3.0 | -10.9  12.4  010  13  7   7.0   3.9
  9750 -10.8  12.6  005  12  6   7.8   4.3 | -10.4  13.3  010  13  7   7.3   4.0
  9500 -10.3  13.5  005  12  6   7.6   4.2 |  -9.9  14.2  010  13  7   6.5   3.6
  9250  -9.7  14.5  005  12  6   7.7   4.2 |  -9.4  15.1  010  13  7   6.8   3.7
  9000  -9.2  15.4  010  12  6   7.0   3.9 |  -8.9  16.0  010  13  7   6.3   3.5
  8750  -8.7  16.3  010  12  6   7.6   4.2 |  -8.4  16.9  015  13  7   7.3   4.0
  8500  -8.1  17.4  010  12  6   8.5   4.7 |  -7.8  18.0  015  12  6   8.3   4.5
  8250  -7.4  18.7  010  12  6   8.1   4.4 |  -7.2  19.0  015  12  6   8.1   4.4
  8000  -6.9  19.6  010  12  6   8.0   4.4 |  -6.6  20.1  010  12  6   8.4   4.6
  7750  -6.3  20.7  010  11  6   7.7   4.2 |  -6.0  21.2  010  12  6   8.1   4.4
  7500  -5.7  21.7  010  11  6   7.5   4.1 |  -5.4  22.3  010  11  6   7.8   4.3
  7250  -5.2  22.6  010  11  6   7.7   4.2 |  -4.8  23.4  010  11  6   8.4   4.6
  7000  -4.6  23.7  010  11  6   7.9   4.3 |  -4.2  24.4  010  11  5   8.8   4.8
  6750  -4.0  24.8  010  11  5   7.8   4.3 |  -3.6  25.5  010  10  5   8.3   4.6
  6500  -3.4  25.9  005  10  5   8.6   4.7 |  -3.0  26.6  010  10  5   8.5   4.7
  6250  -2.7  27.1  005   9  5   9.5   5.2 |  -2.3  27.9  010   9  5   9.1   5.0
  6000  -2.1  28.2  005   9  5   8.7   4.8 |  -1.6  29.1  005   8  4   8.7   4.8
  5750  -1.4  29.5  005   8  4  10.9   6.0 |  -1.0  30.2  005   8  4   9.7   5.3
  5500  -0.4  31.3  005   7  4  16.2   8.9 |  -0.2  31.6  005   7  3  11.8   6.5
________________________________________________________________________________

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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