Soaring Guidance
Issued by NWS Denver/Boulder, CO

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000
UXUS97 KBOU 261220
SRGBOU

Soaring Forecast
National Weather Service Denver/Boulder, Colorado
0520 MST Friday, December 26, 2014

This forecast is for Friday, December 26, 2014:

If the trigger temperature of 25.7 F/-3.5 C is reached...then
   Thermal Soaring Index....................... Poor
   Maximum rate of lift........................ 0 ft/min (0.0 m/s)
   Maximum height of thermals.................. 7766 ft MSL (2481 ft AGL)

Forecast maximum temperature................... 21.0 F/-6.6 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............ 20 mph or less
Height of the -3 thermal index................. None
Thermal soaring outlook for Saturday 12/27..... Poor

Wave Soaring Index............................. Poor
Wave Soaring Index trend (to 1700 MST)......... No change
Height of stable layer (12-18K ft MSL)......... 11931 ft MSL (6646 ft AGL)
Weak PVA/NVA (through 1700 MST)................ Weak PVA
Potential height of wave....................... 20299 ft MSL (15014 ft AGL)
Wave soaring outlook for Saturday 12/27........ Poor

Remarks...

Sunrise/Sunset.................... 07:19:07 / 16:41:17 MST
Total possible sunshine........... 9 hr 22 min 11 sec (562 min 11 sec)
Altitude of sun at 12:00:10 MST... 26.96 degrees

Upper air data from rawinsonde observation taken on 12/26/2014 at 0500 MST

Freezing level.................. Entire airmass below 32 F / 0 C
Convective condensation level... 9722 ft MSL (4437 ft AGL)
Lifted condensation level....... 8404 ft MSL (3119 ft AGL)
Lifted index.................... +14.3
K index......................... +4.5

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  -52.9 -63.2   240   21   11   6.5   3.6  115.5 239.9    68.9      M    M
 45000  -49.7 -57.5   205   44   23 -12.7  -6.9   94.8 202.6    61.3      M    M
 40000  -49.3 -56.7   220   62   32   3.5   1.9   72.1 161.8    50.7      M    M
 38000  -49.5 -57.1   220   53   27  -6.7  -3.7   62.9 145.2    45.9      M    M
 36000  -49.5 -57.1   215   54   28  -1.4  -0.8   54.1 129.5    41.2      M    M
 34000  -50.4 -58.7   215   64   33  -8.3  -4.5   44.4 111.9    35.4      M    M
 32000  -49.3 -56.7   215   79   41  -6.4  -3.5   37.8 100.1    31.6      M    M
 30000  -50.9 -59.6   205   66   34   0.7   0.4   26.6  79.8    24.2      M    M
 29000  -50.7 -59.3   215   64   33   3.3   1.8   22.9  73.2    21.8      M    M
 28000  -49.0 -56.2   210   70   36   8.5   4.6   21.3  70.3    20.9      M    M
 27000  -46.5 -51.7   210   75   38   8.5   4.6   20.7  69.3    20.7      M    M
 26000  -44.4 -47.9   210   67   34   6.4   3.5   19.7  67.4    20.1      M    M
 25000  -42.9 -45.2   210   59   30   4.8   2.6   17.9  64.2    19.0      M    M
 24000  -41.5 -42.7   215   51   26   6.8   3.7   16.0  60.9    17.7      M    M
 23000  -38.8 -37.8   220   51   26   9.6   5.3   15.7  60.2    17.7      M    M
 22000  -35.9 -32.6   220   52   27   8.9   4.9   15.7  60.3    17.9      M    M
 21000  -33.1 -27.6   215   54   28   9.5   5.2   15.5  60.0    18.0      M    M
 20000  -30.4 -22.7   215   55   28   8.4   4.6   15.3  59.6    18.0      M    M
 19500  -29.1 -20.4   215   50   26   8.2   4.5   15.1  59.2    17.9      M    M
 19000  -27.9 -18.2   215   45   23   8.4   4.6   14.8  58.6    17.8      M    M
 18500  -27.0 -16.6   210   39   20   3.7   2.1   14.1  57.4    17.3      M    M
 18000  -26.4 -15.5   210   34   17   4.5   2.5   13.1  55.7    16.6      M    M
 17500  -26.0 -14.8   210   29   15   1.9   1.0   12.0  53.6    15.6      M    M
 17000  -25.7 -14.3   205   25   13   6.1   3.3   10.6  51.2    14.5      M    M
 16500  -24.2 -11.6   205   22   11   9.0   5.0   10.7  51.3    14.6      M    M
 16000  -22.9  -9.2   200   18    9   9.2   5.1   10.5  50.9    14.5      M    M
 15500  -22.1  -7.8   200   17    9  -0.0  -0.0    9.8  49.7    14.0      M    M
 15000  -21.0  -5.8   200   18    9   8.5   4.7    8.6  47.4    13.0      M    M
 14500  -19.8  -3.6   200   19   10   8.4   4.6    8.3  47.0    12.8      M    M
 14000  -18.5  -1.3   200   19   10   8.6   4.7    8.1  46.7    12.7      M    M
 13500  -17.4   0.7   195   19   10   6.3   3.5    7.8  46.0    12.4      M    M
 13000  -16.4   2.5   195   18    9   6.6   3.6    7.2  45.0    12.0      M    M
 12500  -15.5   4.1   190   14    7   6.3   3.5    6.7  44.1    11.6      M    M
 12000  -15.1   4.8   185    9    5  -6.1  -3.3    5.5  41.9    10.5      M    M
 11500  -16.6   2.1   190    5    2 -10.1  -5.5    2.3  36.2     7.6      M    M
 11000  -17.7   0.1   275    1    0  -1.7  -0.9   -0.4  31.2     5.1      M    M
 10500  -17.2   1.0   350    2    1   5.7   3.1   -1.5  29.4     4.2      M    M
 10250  -16.8   1.8   360    3    2   5.2   2.9   -1.8  28.7     3.9      M    M
 10000  -16.4   2.5   360    5    2   5.5   3.0   -2.2  28.1     3.5      M    M
  9750  -16.0   3.2   005    6    3   4.8   2.6   -2.5  27.5     3.2      M    M
  9500  -15.7   3.7   005    6    3   3.8   2.1   -2.9  26.7     2.8      M    M
  9250  -15.4   4.3   360    6    3   3.8   2.1   -3.4  25.9     2.4      M    M
  9000  -15.1   4.8   360    6    3   3.8   2.1   -3.9  25.1     1.9      M    M
  8750  -14.9   5.2   360    7    3   3.8   2.1   -4.3  24.2     1.5      M    M
  8500  -14.6   5.7   360    7    4   3.7   2.0   -4.8  23.4     1.0      M    M
  8250  -14.3   6.3   360    8    4   4.0   2.2   -5.3  22.5     0.6      M    M
  8000  -13.9   7.0   360    8    4   5.9   3.2   -5.6  21.8     0.2      M    M
  7750  -13.4   7.9   005    9    5   7.0   3.9   -5.9  21.4    -0.0    171  0.9
  7500  -12.9   8.8   010   10    5   6.7   3.7   -6.1  21.0    -0.2    149  0.8
  7250  -12.4   9.7   010   11    6   6.8   3.7   -6.3  20.6    -0.5    126  0.6
  7000  -11.9  10.6   015   12    6   6.8   3.7   -6.5  20.2    -0.7    104  0.5
  6750  -11.4  11.5   015   12    6   6.8   3.7   -6.8  19.8    -0.9     82  0.4
  6500  -10.9  12.4   020   12    6   6.8   3.7   -7.0  19.4    -1.2     59  0.3
  6250  -10.4  13.3   020   13    7   6.8   3.7   -7.2  19.0    -1.4     37  0.2
  6000   -9.9  14.2   020   13    7   6.8   3.7   -7.4  18.6    -1.6     14  0.1
  5750   -9.4  15.1   015   11    6   7.8   4.3   -7.6  18.3    -1.8      M    M
  5500   -8.7  16.3   015    8    4  10.5   5.8   -7.7  18.2    -1.9      M    M

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

           12/26/2014 at 0800 MST          |       12/26/2014 at 1100 MST
                                           |
K index... -0.5  LI... +9.0                | K index... -0.5  LI... +8.8
CAPE... 0.0  CIN... M                      | CAPE... 0.0  CIN... -0.5
                                           |
Height Temperature  Wnd WndSpd  Lapse Rate | Temperature  Wnd WndSpd  Lapse Rate
ft MSL deg C deg F  Dir kt m/s  C/km F/kft | deg C deg F  Dir kt m/s  C/km F/kft
--------------------------------------------------------------------------------
 50000 -52.2 -62.0  235  28 14   2.0   1.1 | -52.3 -62.1  235  33 17   1.5   0.8
 45000 -49.3 -56.7  225  34 17   2.0   1.1 | -50.0 -58.0  235  38 20   1.5   0.8
 40000 -47.6 -53.7  220  44 22   0.9   0.5 | -47.2 -53.0  225  45 23   1.9   1.0
 38000 -47.1 -52.8  220  48 25   0.3   0.2 | -46.2 -51.2  225  48 25  -0.1  -0.1
 36000 -47.7 -53.9  220  51 26  -1.1  -0.6 | -46.6 -51.9  220  47 24  -0.7  -0.4
 34000 -48.4 -55.1  220  54 28  -1.1  -0.6 | -47.0 -52.6  215  45 23  -0.7  -0.4
 32000 -49.0 -56.2  215  57 29  -0.8  -0.4 | -47.7 -53.9  215  46 24  -1.3  -0.7
 30000 -49.4 -56.9  210  61 31  -0.7  -0.4 | -48.5 -55.3  215  48 24  -1.3  -0.7
 29000 -49.2 -56.6  210  61 31   4.8   2.6 | -48.6 -55.5  210  48 25   2.8   1.5
 28000 -47.9 -54.2  205  56 29   4.3   2.4 | -47.6 -53.7  210  48 25   3.4   1.8
 27000 -46.6 -51.9  205  51 26   4.3   2.4 | -46.4 -51.5  205  48 24   3.4   1.9
 26000 -45.3 -49.5  200  47 24   5.1   2.8 | -45.4 -49.7  200  48 25   5.1   2.8
 25000 -43.3 -45.9  200  44 23   6.8   3.7 | -43.3 -45.9  195  47 24   6.8   3.8
 24000 -41.3 -42.3  200  42 21   6.8   3.7 | -41.3 -42.3  195  46 23   6.9   3.8
 23000 -39.3 -38.7  200  39 20   7.3   4.0 | -39.2 -38.6  195  45 23   7.1   3.9
 22000 -36.8 -34.2  200  38 20   8.2   4.5 | -37.0 -34.6  195  40 21   7.3   4.0
 21000 -34.3 -29.7  205  37 19   8.2   4.5 | -34.9 -30.8  195  36 19   7.3   4.0
 20000 -32.0 -25.6  205  36 18   6.8   3.7 | -32.7 -26.9  195  32 17   6.7   3.6
 19500 -30.9 -23.6  205  34 18   6.8   3.8 | -31.7 -25.1  195  31 16   6.7   3.7
 19000 -29.9 -21.8  205  32 17   6.8   3.8 | -30.7 -23.3  195  30 15   6.7   3.7
 18500 -28.9 -20.0  205  31 16   6.9   3.8 | -29.7 -21.5  200  28 15   6.7   3.7
 18000 -27.8 -18.0  205  29 15   6.9   3.8 | -28.7 -19.7  200  27 14   6.7   3.7
 17500 -26.9 -16.4  205  27 14   6.0   3.3 | -27.7 -17.9  200  26 13   7.3   4.0
 17000 -25.5 -13.9  205  25 13   6.0   3.3 | -26.6 -15.9  200  24 13   7.3   4.0
 16500 -24.6 -12.3  205  24 12   6.1   3.3 | -25.5 -13.9  200  23 12   6.3   3.4
 16000 -23.7 -10.7  205  23 12   6.2   3.4 | -24.7 -12.5  200  22 11   5.9   3.2
 15500 -22.8  -9.0  205  22 11   5.8   3.2 | -23.8 -10.8  205  20 10   5.4   3.0
 15000 -22.0  -7.6  205  22 11   5.8   3.2 | -23.1  -9.6  205  19 10   4.7   2.6
 14500 -21.2  -6.2  205  21 11   5.6   3.1 | -22.5  -8.5  205  17  9   5.1   2.8
 14000 -20.4  -4.7  200  19 10   5.5   3.0 | -21.0  -5.8  200  13  7   7.2   3.9
 13500 -19.6  -3.3  200  18  9   5.3   2.9 | -20.0  -4.0  195  10  5   5.6   3.1
 13000 -18.8  -1.8  195  14  7   5.1   2.8 | -19.3  -2.7  175   7  4   4.9   2.7
 12500 -18.1  -0.6  185  11  6   2.1   1.2 | -18.6  -1.5  145   6  3   1.6   0.9
 12000 -18.1  -0.6  165   7  3  -0.1  -0.1 | -18.7  -1.7  110   5  3  -0.2  -0.1
 11500 -18.1  -0.6  125   4  2   0.4   0.2 | -18.7  -1.7  085   6  3   0.7   0.4
 11000 -18.0  -0.4  080   4  2   0.7   0.4 | -18.5  -1.3  070   6  3   0.8   0.5
 10500 -17.7   0.1  050   5  2   3.6   2.0 | -18.1  -0.6  055   5  3   5.0   2.8
 10250 -17.4   0.7  045   5  2   4.6   2.5 | -17.7   0.1  050   5  3   5.8   3.2
 10000 -17.1   1.2  040   5  2   4.2   2.3 | -17.3   0.9  040   5  3   6.0   3.3
  9750 -16.7   1.9  040   5  2   5.9   3.2 | -16.8   1.8  030   5  3   6.4   3.5
  9500 -16.2   2.8  035   5  2   6.8   3.7 | -16.4   2.5  020   5  3   5.9   3.2
  9250 -15.8   3.6  030   4  2   6.2   3.4 | -15.9   3.4  015   6  3   6.1   3.3
  9000 -15.3   4.5  025   4  2   6.2   3.4 | -15.5   4.1  010   6  3   4.8   2.6
  8750 -14.9   5.2  025   4  2   6.0   3.3 | -15.2   4.6  010   7  3   4.6   2.5
  8500 -14.4   6.1  035   5  2   6.3   3.4 | -14.8   5.4  020   7  3   6.2   3.4
  8250 -14.0   6.8  045   5  3   6.1   3.3 | -14.3   6.3  025   7  3   5.9   3.2
  8000 -13.5   7.7  050   6  3   7.0   3.8 | -13.9   7.0  035   7  4   6.6   3.6
  7750 -12.9   8.8  055   7  4   7.3   4.0 | -13.4   7.9  040   8  4   8.0   4.4
  7500 -12.5   9.5  055   8  4   6.2   3.4 | -12.8   9.0  040   8  4   8.1   4.5
  7250 -12.0  10.4  050   9  5   6.8   3.8 | -12.2  10.0  040   9  5   8.7   4.8
  7000 -11.4  11.5  050   9  5   8.8   4.8 | -11.5  11.3  040   9  5  10.0   5.5
  6750 -10.8  12.6  045   9  5   8.5   4.6 | -10.7  12.7  040   9  5  10.0   5.5
  6500 -10.2  13.6  040   9  5   7.5   4.1 | -10.0  14.0  035   8  4   9.8   5.4
  6250  -9.6  14.7  035   8  4   9.6   5.3 |  -9.3  15.3  035   8  4  10.4   5.7
  6000  -8.8  16.2  035   8  4  11.0   6.0 |  -8.5  16.7  035   8  4  10.8   5.9
  5750  -8.0  17.6  035   8  4  10.1   5.5 |  -7.7  18.1  035   8  4  10.4   5.7
  5500  -7.3  18.9  035   7  4  10.4   5.7 |  -6.9  19.6  035   7  4  12.2   6.7

           12/26/2014 at 1400 MST          |       12/26/2014 at 1700 MST
                                           |
K index... +2.2  LI... +6.9                | K index... +6.3  LI... +6.3
CAPE... +35.2  CIN... M                    | CAPE... 0.0  CIN... M
                                           |
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 -51.6 -60.9  230  32 16   1.5   0.8 | -52.8 -63.0  235  30 15   2.5   1.4
 45000 -49.4 -56.9  230  36 19   1.5   0.8 | -49.0 -56.2  235  32 17   2.5   1.4
 40000 -47.1 -52.8  230  43 22   1.5   0.8 | -46.6 -51.9  235  36 19   1.4   0.7
 38000 -46.3 -51.3  230  46 24   0.6   0.3 | -45.8 -50.4  235  38 19   1.2   0.7
 36000 -46.1 -51.0  225  46 24   0.2   0.1 | -45.1 -49.2  230  38 20   1.2   0.6
 34000 -46.0 -50.8  215  47 24   0.2   0.1 | -44.4 -47.9  225  39 20   1.2   0.6
 32000 -46.1 -51.0  210  46 24  -0.5  -0.3 | -44.5 -48.1  220  35 18  -1.1  -0.6
 30000 -46.4 -51.5  205  44 22  -0.5  -0.3 | -45.2 -49.4  215  28 14  -1.1  -0.6
 29000 -46.5 -51.7  205  43 22   0.7   0.4 | -45.5 -49.9  215  25 13  -1.7  -0.9
 28000 -46.1 -51.0  200  44 23   1.2   0.6 | -46.2 -51.2  215  23 12  -2.2  -1.2
 27000 -45.7 -50.3  195  46 24   1.2   0.6 | -47.0 -52.6  210  20 10  -2.1  -1.2
 26000 -45.4 -49.7  190  48 25   2.4   1.3 | -47.6 -53.7  205  18  9  -0.6  -0.3
 25000 -43.9 -47.0  190  44 23   5.3   2.9 | -46.1 -51.0  210  16  8   6.0   3.3
 24000 -42.3 -44.1  190  40 21   5.3   2.9 | -44.3 -47.7  215  14  7   6.0   3.3
 23000 -40.7 -41.3  195  37 19   5.9   3.3 | -42.5 -44.5  225  12  6   6.3   3.5
 22000 -38.5 -37.3  195  32 17   7.3   4.0 | -40.4 -40.7  225  11  6   7.2   3.9
 21000 -36.4 -33.5  195  28 14   7.3   4.0 | -38.3 -36.9  230  11  6   7.2   3.9
 20000 -34.2 -29.6  195  24 12   6.5   3.5 | -36.1 -33.0  230  11  5   8.1   4.4
 19500 -33.2 -27.8  195  23 12   6.5   3.6 | -34.9 -30.8  235  11  5   8.0   4.4
 19000 -32.3 -26.1  200  21 11   6.5   3.6 | -33.7 -28.7  235  11  6   8.0   4.4
 18500 -31.3 -24.3  200  20 10   6.5   3.6 | -32.5 -26.5  240  11  6   8.0   4.4
 18000 -30.3 -22.5  205  18  9   6.2   3.4 | -31.3 -24.3  240  11  6   8.0   4.4
 17500 -29.2 -20.6  205  18  9   9.3   5.1 | -30.1 -22.2  245  11  6   8.3   4.6
 17000 -27.9 -18.2  205  18  9   9.1   5.0 | -28.8 -19.8  250  11  6   8.3   4.6
 16500 -26.6 -15.9  205  18  9   7.0   3.8 | -27.7 -17.9  255  11  6   7.2   4.0
 16000 -25.7 -14.3  210  17  9   6.0   3.3 | -26.6 -15.9  255  11  6   6.9   3.8
 15500 -24.8 -12.6  215  15  8   6.1   3.3 | -25.6 -14.1  260  10  5   7.1   3.9
 15000 -23.9 -11.0  215  14  7   6.4   3.5 | -24.5 -12.1  255  10  5   7.4   4.1
 14500 -23.0  -9.4  220  12  6   6.5   3.6 | -23.4 -10.1  255  10  5   7.1   3.9
 14000 -21.4  -6.5  215   9  4   7.0   3.8 | -22.1  -7.8  260   7  4   5.9   3.2
 13500 -20.4  -4.7  205   6  3   5.1   2.8 | -21.3  -6.3  265   6  3   4.0   2.2
 13000 -19.8  -3.6  190   4  2   4.2   2.3 | -20.8  -5.4  275   6  3   3.3   1.8
 12500 -19.3  -2.7  160   3  2   2.0   1.1 | -20.3  -4.5  285   6  3   3.1   1.7
 12000 -19.1  -2.4  150   3  1   0.8   0.4 | -19.8  -3.6  285   6  3   3.0   1.6
 11500 -19.0  -2.2  135   2  1   2.1   1.1 | -19.4  -2.9  285   6  3   3.7   2.1
 11000 -18.6  -1.5  060   2  1   2.5   1.4 | -18.8  -1.8  305   5  3   3.9   2.1
 10500 -18.1  -0.6  025   3  2   4.9   2.7 | -18.2  -0.8  325   5  3   4.7   2.6
 10250 -17.7   0.1  015   4  2   5.3   2.9 | -17.8  -0.0  335   5  3   4.2   2.3
 10000 -17.3   0.9  005   4  2   5.7   3.1 | -17.5   0.5  340   6  3   6.2   3.4
  9750 -16.8   1.8  360   5  3   6.0   3.3 | -16.9   1.6  350   7  4   6.8   3.7
  9500 -16.4   2.5  360   6  3   5.3   2.9 | -16.5   2.3  355   8  4   5.2   2.8
  9250 -16.1   3.0  360   7  4   5.1   2.8 | -16.1   3.0  355   9  5   5.5   3.0
  9000 -15.7   3.7  360   8  4   5.2   2.9 | -15.7   3.7  360  11  5   5.7   3.1
  8750 -15.3   4.5  005   8  4   6.3   3.4 | -15.3   4.5  005  11  6   6.0   3.3
  8500 -14.8   5.4  010   8  4   7.2   4.0 | -14.8   5.4  010  11  6   6.2   3.4
  8250 -14.3   6.3  015   8  4   6.6   3.6 | -14.4   6.1  015  11  6   5.7   3.1
  8000 -13.7   7.3  020   8  4   8.5   4.7 | -13.9   7.0  020  11  6   8.6   4.7
  7750 -13.0   8.6  025   8  4  10.1   5.6 | -13.2   8.2  025  11  6  10.4   5.7
  7500 -12.3   9.9  025   8  4   9.1   5.0 | -12.5   9.5  025  11  5   9.0   4.9
  7250 -11.6  11.1  025   8  4   9.8   5.4 | -11.8  10.8  025  10  5   9.1   5.0
  7000 -10.9  12.4  025   8  4  11.0   6.0 | -11.2  11.8  020  10  5   8.9   4.9
  6750 -10.1  13.8  025   8  4  10.8   5.9 | -10.5  13.1  020  10  5   8.8   4.9
  6500  -9.3  15.3  025   8  4  10.1   5.6 |  -9.9  14.2  020  10  5   9.2   5.1
  6250  -8.6  16.5  025   8  4  10.2   5.6 |  -9.1  15.6  015   9  5  10.2   5.6
  6000  -7.8  18.0  025   8  4  10.2   5.6 |  -8.4  16.9  015   9  4  10.7   5.9
  5750  -7.0  19.4  025   8  4  10.1   5.5 |  -7.6  18.3  015   8  4  10.3   5.7
  5500  -6.2  20.8  025   7  4  12.2   6.7 |  -6.8  19.8  015   8  4  10.2   5.6
________________________________________________________________________________

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.

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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