Soaring Guidance
Issued by NWS Denver/Boulder, CO

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373
UXUS97 KBOU 071317
SRGBOU

Soaring Forecast
National Weather Service Denver/Boulder, Colorado
0617 MST Thursday, December 7, 2017

This forecast is for Thursday, December 7, 2017:

If the trigger temperature of 29.9 F/-1.1 C is reached...then
   Thermal Soaring Index....................... Good
   Maximum rate of lift........................ 597 ft/min (3.0 m/s)
   Maximum height of thermals.................. 14292 ft MSL (9009 ft AGL)

Forecast maximum temperature................... 35.0 F/2.1 C
Time of trigger temperature.................... 1030 MST
Time of overdevelopment........................ None
Middle/high clouds during soaring window....... Broken/overcast thin middle
Surface winds during soaring window............ 20 mph or less
Height of the -3 thermal index................. 8420 ft MSL (3136 ft AGL)
Thermal soaring outlook for Friday 12/08....... Fair

Wave Soaring Index............................. Poor
Wave Soaring Index trend (to 1700 MST)......... Little change
Height of stable layer (12-18K ft MSL)......... None
Weak PVA/NVA (through 1700 MST)................ Neither
Potential height of wave....................... 25993 ft MSL (20710 ft AGL)
Wave soaring outlook for Friday 12/08.......... Poor

Remarks...

Sunrise/Sunset.................... 07:07:36 / 16:34:44 MST
Total possible sunshine........... 9 hr 27 min 7 sec (567 min 7 sec)
Altitude of sun at 11:51:10 MST... 27.51 degrees

Upper air data from numerical model forecast valid on 12/07/2017 at 0500 MST

Freezing level.................. Entire airmass below 32 F / 0 C
Convective condensation level... 11581 ft MSL (6298 ft AGL)
Lifted condensation level....... 12439 ft MSL (7156 ft AGL)
Lifted index.................... +7.4
K index......................... -1.5

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  -57.2 -71.0   310   14    7   2.0   1.1      M     M       M      M    M
 45000  -54.2 -65.6   315   15    8   2.0   1.1      M     M       M      M    M
 40000  -50.5 -58.9   315   12    6   2.6   1.4      M     M       M      M    M
 38000  -49.0 -56.2   315   11    6   1.4   0.8      M     M       M      M    M
 36000  -48.1 -54.6   335   12    6   1.5   0.8      M     M       M      M    M
 34000  -47.0 -52.6   350   15    8   1.6   0.9      M     M       M      M    M
 32000  -46.6 -51.9   360   18    9   0.5   0.3      M     M       M      M    M
 30000  -46.3 -51.3   010   22   11   0.5   0.3      M     M       M      M    M
 29000  -46.1 -51.0   015   25   13   0.9   0.5   29.8  85.7    21.1      M    M
 28000  -45.8 -50.4   015   28   15   0.9   0.5   26.2  79.1    18.6      M    M
 27000  -45.5 -49.9   015   32   16   0.9   0.5   22.8  73.0    16.2      M    M
 26000  -45.1 -49.2   015   34   18   3.8   2.1   19.7  67.4    14.0      M    M
 25000  -43.9 -47.0   015   35   18   4.1   2.2   17.4  63.3    12.4      M    M
 24000  -42.7 -44.9   015   35   18   4.1   2.2   15.3  59.5    10.9      M    M
 23000  -41.3 -42.3   015   35   18   6.0   3.3   13.4  56.1     9.5      M    M
 22000  -39.5 -39.1   015   34   18   6.1   3.4   11.9  53.5     8.4      M    M
 21000  -37.6 -35.7   015   33   17   6.2   3.4   10.7  51.2     7.5      M    M
 20000  -35.7 -32.3   015   32   16   6.9   3.8    9.5  49.1     6.6      M    M
 19500  -34.6 -30.3   010   31   16   7.0   3.8    9.0  48.2     6.2      M    M
 19000  -33.6 -28.5   010   30   15   7.0   3.8    8.5  47.3     5.8      M    M
 18500  -32.5 -26.5   010   29   15   7.0   3.8    8.0  46.5     5.4      M    M
 18000  -31.5 -24.7   010   28   14   6.3   3.4    7.6  45.6     5.1      M    M
 17500  -30.6 -23.1   010   27   14   5.9   3.2    6.9  44.4     4.5      M    M
 17000  -29.7 -21.5   005   25   13   5.6   3.1    6.2  43.2     4.0      M    M
 16500  -28.6 -19.5   360   23   12   4.8   2.6    5.0  40.9     2.9      M    M
 16000  -27.9 -18.2   360   22   11   4.9   2.7    4.1  39.4     2.2      M    M
 15500  -27.2 -17.0   355   21   11   5.1   2.8    3.3  38.0     1.4      M    M
 15000  -26.4 -15.5   350   20   10   5.4   3.0    2.5  36.6     0.7      M    M
 14500  -25.6 -14.1   350   20   10   6.0   3.3    1.9  35.4     0.1      M    M
 14000  -24.7 -12.5   345   19   10   6.4   3.5    1.3  34.3    -0.4    766  3.9
 13500  -23.7 -10.7   345   19   10   7.1   3.9    0.8  33.4    -0.9    720  3.7
 13000  -22.6  -8.7   345   18    9   7.4   4.1    0.4  32.6    -1.3    674  3.4
 12500  -21.4  -6.5   345   18    9   8.0   4.4    0.0  32.1    -1.6    624  3.2
 12000  -20.3  -4.5   345   17    9   8.7   4.8   -0.3  31.5    -1.9    574  2.9
 11500  -18.8  -1.8   340   17    9   9.5   5.2   -0.3  31.5    -2.0    516  2.6
 11000  -17.4   0.7   340   17    9   9.4   5.1   -0.3  31.4    -2.0    459  2.3
 10500  -16.0   3.2   340   17    9   9.4   5.2   -0.4  31.2    -2.1    403  2.0
 10250  -15.3   4.5   340   18    9   8.6   4.7   -0.5  31.2    -2.2    375  1.9
 10000  -14.8   5.4   340   18    9   6.1   3.4   -0.6  30.9    -2.4    351  1.8
  9750  -14.3   6.3   340   18    9   7.7   4.2   -0.9  30.4    -2.6    330  1.7
  9500  -13.6   7.5   340   18    9  10.4   5.7   -0.9  30.3    -2.7    301  1.5
  9250  -12.9   8.8   340   18    9   9.1   5.0   -0.9  30.3    -2.7    272  1.4
  9000  -12.3   9.9   340   18    9   8.1   4.4   -1.0  30.1    -2.8    246  1.2
  8750  -11.7  10.9   340   17    9   8.9   4.9   -1.1  29.9    -2.9    219  1.1
  8500  -11.0  12.2   340   17    9   9.0   4.9   -1.2  29.9    -3.0    192  1.0
  8250  -10.3  13.5   340   16    8   8.2   4.5   -1.3  29.7    -3.1    165  0.8
  8000   -9.7  14.5   340   15    8   7.4   4.1   -1.4  29.4    -3.2    140  0.7
  7750   -9.1  15.6   340   14    7   9.4   5.2   -1.6  29.2    -3.4    115  0.6
  7500   -8.4  16.9   340   13    7   9.2   5.0   -1.5  29.2    -3.3     84  0.4
  7250   -7.8  18.0   340   12    6   7.1   3.9   -1.7  28.9    -3.5     60  0.3
  7000   -7.2  19.0   340   10    5   7.7   4.2   -1.9  28.6    -3.7     35  0.2
  6750   -6.7  19.9   340    9    5   7.2   4.0   -2.0  28.3    -3.9     11  0.1
  6500   -6.1  21.0   335    8    4   7.4   4.1   -2.2  28.0    -4.1      M    M
  6250   -5.5  22.1   330    7    4   9.3   5.1   -2.4  27.7    -4.2      M    M
  6000   -4.9  23.2   325    6    3   5.0   2.7   -2.5  27.5    -4.3      M    M
  5750   -5.0  23.0   315    5    3  -7.3  -4.0   -3.3  26.1    -5.1      M    M
  5500   -5.9  21.4   290    3    1 -15.7  -8.6   -5.0  23.1    -6.9      M    M

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

           12/07/2017 at 0800 MST          |       12/07/2017 at 1100 MST
                                           |
CAPE...     0.0    LI...       +6.6        | CAPE...     0.0    LI...       +6.9
CINH...     0.0    K Index...  -6.7        | CINH...     0.0    K Index...  -3.6
                                           |
Height Temperature  Wnd WndSpd  Lapse Rate | Temperature  Wnd WndSpd  Lapse Rate
ft MSL deg C deg F  Dir kt m/s  C/km F/kft | deg C deg F  Dir kt m/s  C/km F/kft
--------------------------------------------------------------------------------
 50000 -57.1 -70.8  325  12  6   1.8   1.0 | -57.5 -71.5  335  10  5   2.4   1.3
 45000 -54.4 -65.9  335  11  6   1.8   1.0 | -53.9 -65.0  330  12  6   2.3   1.3
 40000 -51.7 -61.1  340  12  6   1.8   1.0 | -51.0 -59.8  345  13  6   1.9   1.0
 38000 -50.6 -59.1  345  13  7   2.1   1.2 | -50.1 -58.2  355  14  7  -0.9  -0.5
 36000 -49.4 -56.9  355  15  8   2.1   1.1 | -50.5 -58.9  015  20 11  -0.6  -0.3
 34000 -48.0 -54.4  005  18  9   2.2   1.2 | -50.9 -59.6  025  27 14  -0.7  -0.4
 32000 -48.1 -54.6  015  24 12  -0.6  -0.3 | -50.6 -59.1  030  37 19   0.6   0.3
 30000 -48.4 -55.1  025  31 16  -0.7  -0.4 | -50.3 -58.5  035  48 24   0.1   0.1
 29000 -48.1 -54.6  025  35 18   1.8   1.0 | -49.1 -56.4  035  49 25   4.9   2.7
 28000 -47.6 -53.7  025  38 19   1.9   1.0 | -47.7 -53.9  035  48 25   4.8   2.6
 27000 -47.0 -52.6  025  41 21   1.8   1.0 | -46.2 -51.2  035  48 25   4.8   2.7
 26000 -46.1 -51.0  025  43 22   6.7   3.7 | -44.5 -48.1  030  47 24   7.5   4.1
 25000 -44.3 -47.7  025  42 22   6.1   3.3 | -42.3 -44.1  030  45 23   7.3   4.0
 24000 -42.4 -44.3  025  41 21   6.1   3.3 | -40.1 -40.2  030  42 22   7.3   4.0
 23000 -40.5 -40.9  025  39 20   7.1   3.9 | -37.9 -36.2  025  40 20   6.9   3.8
 22000 -38.5 -37.3  025  37 19   7.0   3.8 | -35.9 -32.6  025  36 19   7.0   3.8
 21000 -36.4 -33.5  020  35 18   7.0   3.8 | -33.8 -28.8  025  33 17   7.0   3.8
 20000 -34.2 -29.6  020  33 17   7.4   4.1 | -31.8 -25.2  020  31 16   6.4   3.5
 19500 -33.1 -27.6  020  33 17   7.4   4.1 | -30.9 -23.6  020  30 15   6.4   3.5
 19000 -32.0 -25.6  020  32 16   7.4   4.1 | -29.9 -21.8  020  29 15   6.4   3.5
 18500 -30.9 -23.6  020  31 16   7.4   4.1 | -29.0 -20.2  020  28 15   6.4   3.5
 18000 -29.8 -21.6  020  31 16   7.6   4.2 | -27.6 -17.7  020  27 14   6.1   3.3
 17500 -28.6 -19.5  020  30 16   7.7   4.2 | -26.7 -16.1  020  26 13   6.1   3.3
 17000 -27.4 -17.3  020  29 15   7.0   3.8 | -25.7 -14.3  015  25 13   6.1   3.4
 16500 -26.1 -15.0  015  27 14   5.8   3.2 | -24.8 -12.6  015  24 12   6.1   3.3
 16000 -25.3 -13.5  015  26 13   5.5   3.0 | -23.9 -11.0  015  23 12   6.3   3.5
 15500 -24.5 -12.1  015  25 13   5.3   2.9 | -22.9  -9.2  015  22 11   6.4   3.5
 15000 -23.7 -10.7  010  23 12   4.7   2.6 | -22.0  -7.6  015  21 11   5.8   3.2
 14500 -23.0  -9.4  005  22 11   4.2   2.3 | -21.1  -6.0  010  20 10   5.4   3.0
 14000 -22.4  -8.3  005  21 11   4.3   2.4 | -20.3  -4.5  010  20 10   5.2   2.9
 13500 -21.8  -7.2  360  20 10   4.5   2.5 | -19.6  -3.3  005  20 10   5.1   2.8
 13000 -21.1  -6.0  355  20 10   5.0   2.8 | -18.8  -1.8  005  19 10   5.3   2.9
 12500 -20.3  -4.5  355  19 10   5.7   3.1 | -18.0  -0.4  360  19 10   5.5   3.0
 12000 -19.4  -2.9  355  19 10   6.1   3.4 | -17.2   1.0  360  19 10   5.4   3.0
 11500 -18.5  -1.3  355  18  9   6.5   3.5 | -16.4   2.5  360  19 10   5.4   2.9
 11000 -17.5   0.5  350  17  9   8.3   4.5 | -15.6   3.9  360  18  9   5.4   3.0
 10500 -16.1   3.0  350  17  9   9.0   5.0 | -14.8   5.4  360  17  9   5.4   2.9
 10250 -15.5   4.1  345  17  9   8.9   4.9 | -14.5   5.9  355  17  9   6.4   3.5
 10000 -14.8   5.4  345  18  9   8.0   4.4 | -13.9   7.0  355  17  9   7.4   4.0
  9750 -14.2   6.4  345  18  9   9.5   5.2 | -13.3   8.1  355  17  9   9.6   5.3
  9500 -13.4   7.9  345  18  9  11.6   6.3 | -12.5   9.5  355  17  9  11.8   6.5
  9250 -12.6   9.3  345  18  9   9.8   5.4 | -11.7  10.9  350  18  9   9.6   5.2
  9000 -11.9  10.6  345  17  9   8.2   4.5 | -11.0  12.2  350  17  9   8.0   4.4
  8750 -11.3  11.7  345  17  9   9.6   5.3 | -10.4  13.3  350  17  9   8.9   4.9
  8500 -10.5  13.1  340  16  8   9.5   5.2 |  -9.7  14.5  345  16  8   8.8   4.8
  8250  -9.9  14.2  340  15  8   7.8   4.3 |  -9.1  15.6  345  15  8   8.1   4.5
  8000  -9.3  15.3  340  14  7   6.6   3.6 |  -8.5  16.7  340  14  7   7.6   4.2
  7750  -8.8  16.2  340  13  7   9.7   5.3 |  -7.9  17.8  340  13  7   8.8   4.8
  7500  -8.0  17.6  340  12  6   8.9   4.9 |  -7.2  19.0  340  12  6   8.4   4.6
  7250  -7.5  18.5  335  11  5   5.3   2.9 |  -6.6  20.1  335  10  5   7.1   3.9
  7000  -7.1  19.2  335   9  5   6.4   3.5 |  -6.1  21.0  330   9  4   6.9   3.8
  6750  -6.6  20.1  335   8  4   5.6   3.1 |  -5.5  22.1  325   7  4   8.8   4.8
  6500  -6.2  20.8  330   7  4   6.0   3.3 |  -4.8  23.4  325   6  3  10.0   5.5
  6250  -5.7  21.7  325   6  3   7.2   4.0 |  -4.1  24.6  320   5  3   8.9   4.9
  6000  -5.2  22.6  320   5  2   5.7   3.1 |  -3.4  25.9  315   4  2   9.5   5.2
  5750  -5.0  23.0  305   3  2  -3.2  -1.8 |  -2.6  27.3  310   4  2  13.4   7.4
  5500  -5.7  21.7  280   2  1 -14.8  -8.1 |  -1.3  29.7  310   4  2  19.5  10.7

           12/07/2017 at 1400 MST          |       12/07/2017 at 1700 MST
                                           |
CAPE...     0.0    LI...       +5.5        | CAPE...     0.0    LI...       +5.8
CINH...     0.0    K Index...  +9.8        | CINH...     0.0    K Index... +10.8
                                           |
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 -57.5 -71.5  340  10  5   1.9   1.1 | -58.7 -73.7  345  13  7   1.8   1.0
 45000 -54.6 -66.3  340  13  7   1.9   1.1 | -56.0 -68.8  345  16  8   1.8   1.0
 40000 -51.7 -61.1  010  15  8   1.9   1.0 | -54.8 -66.6  015  20 10   0.6   0.3
 38000 -51.3 -60.3  020  19 10  -2.6  -1.4 | -54.8 -66.6  030  26 13  -1.4  -0.7
 36000 -52.9 -63.2  030  30 15  -2.7  -1.5 | -55.7 -68.3  035  38 20  -1.4  -0.8
 34000 -54.5 -66.1  035  41 21  -3.3  -1.8 | -56.5 -69.7  040  52 27  -0.8  -0.5
 32000 -52.7 -62.9  035  48 24   3.9   2.1 | -53.0 -63.4  040  54 28   6.4   3.5
 30000 -50.4 -58.7  040  54 28   3.7   2.1 | -49.2 -56.6  040  55 28   6.8   3.7
 29000 -48.5 -55.3  040  54 28   7.3   4.0 | -47.0 -52.6  035  53 27   7.4   4.1
 28000 -45.7 -50.3  035  52 27   7.3   4.0 | -44.2 -47.6  035  51 26   7.4   4.1
 27000 -43.5 -46.3  035  51 26   7.3   4.0 | -42.0 -43.6  030  49 25   7.4   4.1
 26000 -41.4 -42.5  035  49 25   6.9   3.8 | -39.9 -39.8  030  47 24   7.2   4.0
 25000 -39.4 -38.9  035  47 24   6.9   3.8 | -37.7 -35.9  030  45 23   7.2   4.0
 24000 -37.3 -35.1  030  44 23   6.9   3.8 | -35.6 -32.1  025  43 22   7.2   3.9
 23000 -35.3 -31.5  030  41 21   6.5   3.6 | -33.3 -27.9  025  41 21   7.8   4.3
 22000 -33.4 -28.1  030  37 19   6.5   3.6 | -31.0 -23.8  025  38 20   7.8   4.3
 21000 -31.4 -24.5  025  34 17   6.5   3.6 | -28.7 -19.7  025  36 18   7.4   4.1
 20000 -29.6 -21.3  025  31 16   6.0   3.3 | -26.9 -16.4  020  33 17   5.6   3.1
 19500 -28.7 -19.7  020  30 16   6.0   3.3 | -26.1 -15.0  020  32 17   5.7   3.1
 19000 -27.8 -18.0  020  29 15   6.0   3.3 | -25.3 -13.5  020  31 16   5.7   3.1
 18500 -26.9 -16.4  015  28 15   6.0   3.3 | -24.4 -11.9  015  30 16   5.6   3.1
 18000 -26.0 -14.8  015  27 14   6.3   3.5 | -23.6 -10.5  015  30 15   5.4   2.9
 17500 -25.1 -13.2  015  27 14   6.3   3.4 | -22.8  -9.0  010  29 15   5.4   3.0
 17000 -24.1 -11.4  015  26 13   6.2   3.4 | -22.0  -7.6  010  28 15   5.1   2.8
 16500 -23.2  -9.8  010  25 13   6.2   3.4 | -21.3  -6.3  010  27 14   5.0   2.8
 16000 -22.3  -8.1  010  24 13   5.8   3.2 | -20.5  -4.9  010  27 14   5.4   2.9
 15500 -21.5  -6.7  010  23 12   5.1   2.8 | -19.7  -3.5  005  26 13   5.7   3.1
 15000 -20.8  -5.4  005  23 12   5.1   2.8 | -18.4  -1.1  005  25 13   6.1   3.3
 14500 -20.0  -4.0  005  22 11   5.5   3.0 | -17.5   0.5  005  24 13   6.2   3.4
 14000 -18.8  -1.8  360  22 11   5.7   3.2 | -16.6   2.1  005  24 12   5.5   3.0
 13500 -17.9  -0.2  360  21 11   5.9   3.2 | -15.8   3.6  360  24 12   5.2   2.9
 13000 -17.1   1.2  360  21 11   5.3   2.9 | -15.1   4.8  360  23 12   5.6   3.1
 12500 -16.3   2.7  360  20 11   4.9   2.7 | -14.2   6.4  360  23 12   5.9   3.2
 12000 -15.6   3.9  360  20 10   5.6   3.0 | -13.3   8.1  360  22 11   6.1   3.3
 11500 -14.7   5.5  360  20 10   5.9   3.2 | -12.4   9.7  355  21 11   6.1   3.4
 11000 -13.9   7.0  360  19 10   6.6   3.6 | -11.6  11.1  355  21 11   5.6   3.1
 10500 -12.8   9.0  355  18  9   6.9   3.8 | -10.8  12.6  355  21 11   5.5   3.0
 10250 -12.3   9.9  355  17  9   6.5   3.6 | -10.4  13.3  355  20 11   4.8   2.7
 10000 -11.9  10.6  355  17  9   5.9   3.2 | -10.1  13.8  350  20 11   3.9   2.1
  9750 -11.4  11.5  350  16  8   7.0   3.9 |  -9.7  14.5  350  20 10   6.4   3.5
  9500 -10.9  12.4  350  16  8   7.9   4.3 |  -9.1  15.6  350  19 10   8.9   4.9
  9250 -10.3  13.5  345  15  8   7.4   4.1 |  -8.5  16.7  345  19 10   6.8   3.7
  9000  -9.8  14.4  345  14  7   6.8   3.8 |  -8.1  17.4  345  18  9   4.9   2.7
  8750  -9.2  15.4  345  13  7   8.1   4.4 |  -7.7  18.1  345  16  8   6.6   3.6
  8500  -8.5  16.7  345  12  6   8.9   4.9 |  -7.2  19.0  340  15  7   7.2   3.9
  8250  -7.9  17.8  345  11  6   8.1   4.4 |  -6.7  19.9  335  13  7   5.6   3.1
  8000  -7.3  18.9  340  11  6   7.7   4.2 |  -6.3  20.7  335  11  6   5.1   2.8
  7750  -6.7  19.9  340  10  5   8.8   4.9 |  -5.9  21.4  330  10  5   5.5   3.0
  7500  -6.0  21.2  340   9  5  10.2   5.6 |  -5.5  22.1  320   9  5   6.0   3.3
  7250  -5.2  22.6  340   9  5   9.9   5.4 |  -5.1  22.8  315   8  4   6.1   3.3
  7000  -4.5  23.9  340   8  4  10.2   5.6 |  -4.6  23.7  305   7  4   6.0   3.3
  6750  -3.7  25.3  340   8  4   9.0   5.0 |  -4.2  24.4  295   7  4   6.2   3.4
  6500  -3.1  26.4  340   7  4   9.3   5.1 |  -3.7  25.3  285   7  3   7.3   4.0
  6250  -2.3  27.9  335   7  4  10.5   5.8 |  -3.1  26.4  280   6  3   7.4   4.1
  6000  -1.5  29.3  335   7  3  10.7   5.9 |  -2.5  27.5  270   6  3   8.5   4.7
  5750  -0.7  30.7  335   6  3  11.8   6.5 |  -1.8  28.8  260   5  3  10.3   5.7
  5500   0.2  32.4  335   5  3  11.9   6.5 |  -1.1  30.0  255   4  2   9.6   5.3
________________________________________________________________________________

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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