Soaring Guidance
Issued by NWS Pueblo, CO

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000
UXUS97 KPUB 251106
SRGPUB

Soaring Forecast
National Weather Service Pueblo, Colorado
0506 MDT Saturday, April 25, 2015

This forecast is for Saturday, April 25, 2015:

If the trigger temperature of 54.0 F/12.2 C is reached...then
   Thermal Soaring Index....................... Excellent
   Maximum rate of lift........................ 1126 ft/min (5.7 m/s)
   Maximum height of thermals.................. 18716 ft MSL (11546 ft AGL)

Forecast maximum temperature................... 61.0 F/16.6 C
Time of trigger temperature.................... 0845 MDT
Time of overdevelopment........................ 1200 MDT
Middle/high clouds during soaring window....... None
Surface winds during soaring window............ 20 mph or less
Height of the -3 thermal index................. 13845 ft MSL (6675 ft AGL)
Thermal soaring outlook for Sunday 04/26....... Fair

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

Remarks...

Sunrise/Sunset.................... 06:08:59 / 19:44:46 MDT
Total possible sunshine........... 13 hr 35 min 46 sec (815 min 46 sec)
Altitude of sun at 12:57:02 MDT... 64.32 degrees

Upper air data from numerical model forecast valid on 04/25/2015 at 0600 MDT

Freezing level.................. 11260 ft MSL (4090 ft AGL)
Convective condensation level... 16673 ft MSL (9503 ft AGL)
Lifted condensation level....... 17346 ft MSL (10176 ft AGL)
Lifted index.................... -1.1
K index......................... +8.9

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  -55.3 -67.5   240   40   21   0.8   0.4      M     M       M      M    M
 45000  -54.1 -65.4   250   43   22   0.3   0.2      M     M       M      M    M
 40000  -57.1 -70.8   260   51   26  -2.1  -1.2      M     M       M      M    M
 38000  -57.3 -71.1   265   55   28   2.4   1.3      M     M       M      M    M
 36000  -55.9 -68.6   270   60   31   2.4   1.3      M     M       M      M    M
 34000  -54.3 -65.7   275   64   33   6.2   3.4      M     M       M      M    M
 32000  -49.7 -57.5   275   49   25   7.6   4.2      M     M       M      M    M
 30000  -45.2 -49.4   280   35   18   7.2   3.9   25.0  77.0     6.8      M    M
 29000  -43.1 -45.6   280   31   16   7.0   3.9   23.8  74.8     5.9      M    M
 28000  -40.5 -40.9   285   26   13   7.0   3.9   22.5  72.4     5.0      M    M
 27000  -38.4 -37.1   285   22   11   7.2   3.9   21.6  70.8     4.4      M    M
 26000  -36.1 -33.0   285   20   10   7.6   4.2   20.6  69.1     3.6      M    M
 25000  -33.8 -28.8   280   18   10   7.6   4.2   19.8  67.7     3.0      M    M
 24000  -31.6 -24.9   280   17    9   7.6   4.2   19.1  66.4     2.5      M    M
 23000  -29.1 -20.4   280   16    8   8.4   4.6   18.5  65.3     2.0      M    M
 22000  -26.6 -15.9   280   15    8   8.4   4.6   18.0  64.4     1.6      M    M
 21000  -24.1 -11.4   280   14    7   8.2   4.5   17.6  63.7     1.2      M    M
 20000  -21.7  -7.1   280   13    7   8.0   4.4   16.9  62.5     0.6      M    M
 19500  -20.5  -4.9   275   13    7   8.0   4.4   16.6  61.9     0.4      M    M
 19000  -19.3  -2.7   275   13    6   8.0   4.4   16.4  61.4     0.1      M    M
 18500  -18.1  -0.6   270   12    6   7.9   4.3   16.1  61.0    -0.1   1105  5.6
 18000  -17.0   1.4   270   13    7   7.5   4.1   15.7  60.3    -0.4   1057  5.4
 17500  -15.9   3.4   265   14    7   7.4   4.1   15.4  59.6    -0.8   1009  5.1
 17000  -14.7   5.5   265   16    8   8.0   4.4   15.0  59.0    -1.1    960  4.9
 16500  -13.5   7.7   260   17    9   8.0   4.4   14.7  58.5    -1.4    910  4.6
 16000  -12.4   9.7   260   18    9   8.0   4.4   14.4  58.0    -1.7    860  4.4
 15500  -11.2  11.8   255   17    9   8.0   4.4   14.1  57.4    -2.0    810  4.1
 15000  -10.0  14.0   255   16    8   8.0   4.4   13.8  56.9    -2.3    759  3.9
 14500   -8.8  16.2   255   14    7   8.1   4.5   13.6  56.4    -2.6    709  3.6
 14000   -7.6  18.3   250   12    6   8.1   4.5   13.3  56.0    -2.9    658  3.3
 13500   -6.4  20.5   255   10    5   8.6   4.7   13.1  55.5    -3.1    606  3.1
 13000   -5.1  22.8   255    8    4   8.3   4.6   12.9  55.2    -3.3    553  2.8
 12500   -3.7  25.3   260    7    3  11.0   6.0   12.9  55.1    -3.4    496  2.5
 12000   -2.2  28.0   270    6    3   8.0   4.4   12.8  55.1    -3.4    437  2.2
 11750   -1.6  29.1   285    6    3   8.3   4.5   12.7  54.9    -3.6    412  2.1
 11500   -1.0  30.2   290    6    3   9.1   5.0   12.6  54.7    -3.7    385  2.0
 11250   -0.3  31.5   300    7    4   9.2   5.1   12.6  54.6    -3.7    357  1.8
 11000    0.4  32.7   305    8    4   8.8   4.8   12.5  54.6    -3.8    329  1.7
 10750    1.0  33.8   305    9    5   8.2   4.5   12.4  54.4    -3.9    303  1.5
 10500    1.7  35.1   305   11    6   8.3   4.6   12.3  54.2    -4.0    276  1.4
 10250    2.9  37.2   305   15    8   8.7   4.8   12.1  53.8    -4.2    224  1.1
 10000    3.5  38.3   305   17    9   7.7   4.2   12.0  53.6    -4.3    198  1.0
  9750    4.0  39.2   300   18   10   5.7   3.1   11.7  53.1    -4.6    177  0.9
  9500    4.4  39.9   300   21   11   5.4   3.0   11.4  52.5    -5.0    158  0.8
  9250    4.8  40.6   300   23   12   5.5   3.0   11.1  51.9    -5.4    139  0.7
  9000    5.2  41.4   300   26   13   6.1   3.4   10.8  51.4    -5.7    120  0.6
  8750    5.6  42.1   300   25   13   4.4   2.4   10.5  50.8    -6.0    100  0.5
  8500    5.8  42.4   300   25   13   2.9   1.6   10.0  49.9    -6.6     87  0.4
  8250    6.0  42.8   300   25   13   2.7   1.5    9.5  49.0    -7.1     73  0.4
  8000    6.0  42.8   295   25   13  -0.1  -0.1    8.8  47.9    -7.8     64  0.3
  7750    5.7  42.3   295   21   11 -11.5  -6.3    7.8  46.0    -8.9     67  0.3
  7500    4.2  39.6   295   15    8 -26.8 -14.7    5.5  41.9   -11.2    105  0.5
  7250    2.6  36.7   290    8    4  -0.6  -0.3    3.3  37.9   -13.5    143  0.7
  7000      M     M     M    M    M     M     M      M     M       M      M    M
  6750      M     M     M    M    M     M     M      M     M       M      M    M

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

           04/25/2015 at 0900 MDT          |       04/25/2015 at 1200 MDT
                                           |
K index... +6.6  LI... +274.3              | K index... +18.6  LI... +271.9
CAPE... 0.0  CIN... M                      | CAPE... +144.9  CIN... -11.0
                                           |
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 -55.4 -67.7  235  37 19   0.8   0.4 | -55.3 -67.5  240  38 19   0.6   0.3
 45000 -54.1 -65.4  245  39 20   0.1   0.0 | -54.4 -65.9  250  39 20  -0.2  -0.1
 40000 -58.4 -73.1  260  52 27  -2.9  -1.6 | -58.4 -73.1  250  54 28  -2.8  -1.5
 38000 -58.5 -73.3  260  57 29   3.9   2.1 | -58.4 -73.1  250  58 30   4.0   2.2
 36000 -56.1 -69.0  260  62 32   3.9   2.1 | -56.0 -68.8  250  62 32   4.0   2.2
 34000 -53.7 -64.7  265  65 34   6.7   3.7 | -53.4 -64.1  250  64 33   6.4   3.5
 32000 -49.4 -56.9  260  55 28   7.2   3.9 | -49.4 -56.9  250  54 28   6.7   3.7
 30000 -45.0 -49.0  260  44 23   7.6   4.2 | -45.4 -49.7  250  45 23   7.8   4.3
 29000 -42.8 -45.0  260  38 20   7.5   4.1 | -42.5 -44.5  250  38 20   7.7   4.2
 28000 -40.0 -40.0  260  31 16   7.5   4.1 | -40.2 -40.4  250  33 17   7.7   4.2
 27000 -37.7 -35.9  260  26 13   7.5   4.1 | -37.9 -36.2  250  28 14   7.9   4.3
 26000 -35.5 -31.9  260  23 12   7.5   4.1 | -35.4 -31.7  250  24 13   8.2   4.5
 25000 -33.2 -27.8  265  20 10   7.5   4.1 | -33.0 -27.4  250  21 11   8.2   4.5
 24000 -30.9 -23.6  265  17  9   7.6   4.2 | -30.5 -22.9  250  17  9   8.2   4.5
 23000 -28.6 -19.5  265  16  8   8.0   4.4 | -28.1 -18.6  240  16  8   8.2   4.5
 22000 -26.2 -15.2  270  16  8   8.0   4.4 | -25.6 -14.1  235  15  8   8.2   4.5
 21000 -23.7 -10.7  270  15  8   8.1   4.5 | -23.2  -9.8  225  14  7   7.8   4.3
 20000 -21.3  -6.3  270  15  8   8.2   4.5 | -21.0  -5.8  230  13  7   7.5   4.1
 19500 -20.1  -4.2  270  15  8   8.2   4.5 | -19.8  -3.6  230  13  7   7.5   4.1
 19000 -18.9  -2.0  270  15  8   8.2   4.5 | -18.7  -1.7  230  12  6   7.6   4.1
 18500 -17.6   0.3  270  15  8   8.0   4.4 | -17.6   0.3  230  12  6   7.5   4.1
 18000 -16.5   2.3  270  15  8   7.7   4.2 | -16.5   2.3  235  13  6   7.5   4.1
 17500 -15.3   4.5  275  15  8   7.7   4.2 | -15.4   4.3  240  13  7   7.4   4.1
 17000 -14.2   6.4  270  15  8   7.6   4.2 | -14.2   6.4  240  14  7   8.0   4.4
 16500 -13.1   8.4  270  15  8   7.6   4.2 | -13.1   8.4  245  15  8   8.0   4.4
 16000 -11.9  10.6  265  15  8   7.0   3.8 | -11.9  10.6  245  16  8   8.1   4.4
 15500 -11.0  12.2  250  15  8   6.6   3.6 | -10.7  12.7  250  16  8   8.2   4.5
 15000 -10.0  14.0  240  15  8   7.0   3.9 |  -9.5  14.9  250  16  8   8.2   4.5
 14500  -8.8  16.2  230  15  8   8.2   4.5 |  -8.3  17.1  250  16  8   8.3   4.5
 14000  -7.6  18.3  225  14  7   8.2   4.5 |  -7.1  19.2  250  14  7   8.3   4.5
 13500  -6.4  20.5  220  13  7   8.4   4.6 |  -5.9  21.4  250  13  6   7.7   4.3
 13000  -5.1  22.8  205  13  6   8.2   4.5 |  -4.8  23.4  250  10  5   7.8   4.3
 12500  -3.8  25.2  200  12  6  10.2   5.6 |  -3.6  25.5  245   8  4   8.6   4.7
 12000  -2.4  27.7  195  11  5   7.8   4.3 |  -2.5  27.5  235   6  3   7.6   4.1
 11750  -1.8  28.8  195  10  5   8.5   4.7 |  -1.9  28.6  220   5  3   8.4   4.6
 11500  -1.1  30.0  195   9  5   9.6   5.3 |  -1.2  29.8  215   5  3   9.4   5.2
 11250  -0.4  31.3  195   8  4   9.7   5.3 |  -0.6  30.9  210   5  3   9.2   5.1
 11000   0.3  32.5  195   8  4   8.8   4.8 |   0.1  32.2  205   5  3   9.5   5.2
 10750   0.9  33.6  200   6  3   8.0   4.4 |   0.9  33.6  200   5  3   9.7   5.3
 10500   2.2  36.0  230   5  2   8.4   4.6 |   2.3  36.1  200   6  3   9.6   5.2
 10250   2.8  37.0  255   4  2   8.1   4.5 |   3.0  37.4  200   6  3  10.0   5.5
 10000   3.3  37.9  270   5  3   5.4   3.0 |   3.8  38.8  195   6  3  10.3   5.6
  9750   3.6  38.5  280   7  4   4.2   2.3 |   4.5  40.1  190   6  3   9.9   5.4
  9500   3.9  39.0  290  10  5   5.0   2.7 |   5.3  41.5  190   6  3   9.9   5.4
  9250   4.2  39.6  295  12  6   4.8   2.6 |   6.0  42.8  190   6  3   9.9   5.4
  9000   4.6  40.3  295  14  7   6.1   3.3 |   6.8  44.2  190   6  3  10.1   5.6
  8750   5.1  41.2  295  13  7   7.1   3.8 |   7.5  45.5  185   6  3  10.5   5.7
  8500   5.5  41.9  295  12  6   6.5   3.6 |   8.3  46.9  185   6  3  10.4   5.7
  8250   6.0  42.8  295  12  6   7.2   3.9 |   9.1  48.4  185   6  3  10.6   5.8
  8000   6.5  43.7  290  10  5   8.3   4.5 |   9.9  49.8  180   6  3  10.9   6.0
  7750   7.3  45.1  285   9  5  12.7   7.0 |  10.9  51.6  180   6  3  17.2   9.4
  7500   8.4  47.1  285   8  4  19.1  10.5 |  12.5  54.5  180   6  3  27.0  14.8
  7250   9.6  49.3  285   7  4   7.9   4.4 |  14.2  57.6  175   6  3   9.8   5.4
  7000     M     M    M   M  M     M     M |     M     M    M   M  M     M     M
  6750     M     M    M   M  M     M     M |     M     M    M   M  M     M     M

           04/25/2015 at 1500 MDT          |       04/25/2015 at 1800 MDT
                                           |
K index... +24.6  LI... +272.4             | K index... +25.0  LI... +272.3
CAPE... +95.8  CIN... -0.8                 | CAPE... +114.3  CIN... -31.6
                                           |
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 -55.7 -68.3  245  37 19   1.4   0.8 | -56.1 -69.0  245  34 17   1.0   0.5
 45000 -53.7 -64.7  255  42 21   0.5   0.3 | -54.5 -66.1  250  42 22   0.2   0.1
 40000 -57.4 -71.3  250  55 28  -2.6  -1.4 | -56.7 -70.1  250  43 22  -1.5  -0.8
 38000 -58.0 -72.4  245  57 29   1.9   1.0 | -57.1 -70.8  250  40 21   0.4   0.2
 36000 -56.8 -70.2  250  54 28   1.8   1.0 | -56.9 -70.4  255  34 17   0.3   0.2
 34000 -55.0 -67.0  250  49 25   8.9   4.9 | -56.3 -69.3  265  28 14   8.1   4.4
 32000 -50.0 -58.0  255  38 20   8.3   4.6 | -51.1 -60.0  265  21 11   8.7   4.8
 30000 -45.0 -49.0  260  28 15   9.2   5.1 | -45.8 -50.4  270  16  8   9.6   5.3
 29000 -42.2 -44.0  260  26 13   9.2   5.1 | -43.0 -45.4  265  15  8   9.4   5.1
 28000 -39.4 -38.9  260  23 12   9.2   5.1 | -39.5 -39.1  260  15  8   9.4   5.1
 27000 -36.7 -34.1  260  21 11   9.1   5.0 | -36.7 -34.1  255  14  7   8.9   4.9
 26000 -34.2 -29.6  260  19 10   8.3   4.6 | -34.2 -29.6  250  15  8   8.5   4.7
 25000 -31.7 -25.1  255  17  9   8.3   4.6 | -31.6 -24.9  245  15  8   8.5   4.7
 24000 -29.2 -20.6  255  15  8   8.4   4.6 | -29.1 -20.4  240  16  8   8.4   4.6
 23000 -26.2 -15.2  250  14  7   8.0   4.4 | -26.7 -16.1  240  17  9   7.9   4.3
 22000 -23.9 -11.0  245  13  7   8.0   4.4 | -24.4 -11.9  240  17  9   7.9   4.3
 21000 -21.5  -6.7  240  12  6   7.5   4.1 | -22.1  -7.8  240  18  9   7.7   4.2
 20000 -19.4  -2.9  235  10  5   7.4   4.1 | -19.8  -3.6  240  18  9   7.6   4.2
 19500 -18.3  -0.9  230  10  5   7.4   4.1 | -18.7  -1.7  240  18  9   7.6   4.2
 19000 -17.2   1.0  225   9  5   7.4   4.1 | -17.5   0.5  240  18 10   7.7   4.2
 18500 -16.1   3.0  220   9  5   7.5   4.1 | -16.4   2.5  240  19 10   7.7   4.2
 18000 -15.0   5.0  220   9  5   7.5   4.1 | -15.3   4.5  240  19 10   7.7   4.2
 17500 -13.9   7.0  220   9  4   7.6   4.2 | -14.2   6.4  240  19 10   7.7   4.2
 17000 -12.9   8.8  215   9  4   6.8   3.7 | -13.0   8.6  240  18 10   7.7   4.2
 16500 -11.9  10.6  205   9  4   6.8   3.8 | -11.9  10.6  235  18  9   7.7   4.2
 16000 -10.9  12.4  200   9  5   6.9   3.8 | -10.8  12.6  235  18  9   7.4   4.1
 15500  -9.9  14.2  200   9  4   6.9   3.8 |  -9.7  14.5  230  18  9   7.3   4.0
 15000  -8.9  16.0  195   9  4   6.8   3.7 |  -8.7  16.3  230  18  9   7.2   4.0
 14500  -7.9  17.8  195   9  5   6.6   3.6 |  -7.6  18.3  225  18  9   7.0   3.9
 14000  -7.7  18.1  190   9  5   6.6   3.6 |  -6.6  20.1  220  18  9   7.1   3.9
 13500  -6.0  21.2  190   9  5   6.4   3.5 |  -5.6  21.9  220  17  9   7.0   3.9
 13000  -5.1  22.8  185  10  5   6.3   3.4 |  -4.5  23.9  215  17  9   6.9   3.8
 12500  -4.0  24.8  185  10  5   8.7   4.8 |  -3.4  25.9  215  17  9   8.8   4.8
 12000  -3.0  26.6  185  10  5   5.4   3.0 |  -2.3  27.9  215  16  8   5.5   3.0
 11750  -2.5  27.5  185  11  6   7.3   4.0 |  -1.9  28.6  210  16  8   6.1   3.4
 11500  -1.9  28.6  185  11  6   9.2   5.0 |  -1.4  29.5  210  15  8   7.5   4.1
 11250  -1.2  29.8  185  11  6  10.1   5.5 |  -0.9  30.4  210  15  8   8.0   4.4
 11000  -0.6  30.9  185  11  6   5.8   3.2 |  -0.3  31.5  210  15  7   6.5   3.5
 10750  -0.3  31.5  185  11  6   5.4   3.0 |   0.1  32.2  210  14  7   5.8   3.2
 10500   0.3  32.5  185  11  6  10.1   5.5 |   1.1  34.0  210  13  7   7.4   4.1
 10250   1.0  33.8  185  11  6   9.8   5.4 |   1.7  35.1  215  12  6   7.3   4.0
 10000   1.8  35.2  185  11  6   8.8   4.9 |   2.2  36.0  215  11  6   8.8   4.8
  9750   3.2  37.8  185  11  6  10.9   6.0 |   2.9  37.2  215  11  5   9.5   5.2
  9500   4.0  39.2  185  11  6  10.8   5.9 |   3.6  38.5  215  10  5   8.8   4.9
  9250   4.8  40.6  185  11  6  10.8   5.9 |   4.3  39.7  220   9  5   9.4   5.2
  9000   5.6  42.1  185  11  6  10.3   5.6 |   5.0  41.0  225   8  4   7.1   3.9
  8750   6.3  43.3  185  11  6  10.2   5.6 |   5.3  41.5  240   7  4   4.5   2.5
  8500   7.1  44.8  190  11  6  10.5   5.8 |   5.7  42.3  250   6  3   4.9   2.7
  8250   7.9  46.2  190  11  6  10.5   5.8 |   6.0  42.8  260   5  3   4.6   2.5
  8000   8.7  47.7  190  11  6  10.8   5.9 |   6.3  43.3  285   5  2   3.7   2.0
  7750   9.6  49.3  190  11  6  14.2   7.8 |   6.5  43.7  310   6  3   5.4   2.9
  7500  10.8  51.4  190  10  5  19.4  10.6 |   7.0  44.6  320   6  3   9.8   5.4
  7250  12.0  53.6  185  10  5  10.2   5.6 |   7.5  45.5  335   6  3   1.7   0.9
  7000     M     M    M   M  M     M     M |     M     M    M   M  M     M     M
  6750     M     M    M   M  M     M     M |     M     M    M   M  M     M     M
________________________________________________________________________________

This product is issued twice per day, once by approximately 0630 MST/0730 MDT
(1330 UTC) and again by approximately 1830 MST/1930 MDT (0130 UTC).  It is not
continuously monitored nor updated after its initial issuance.

The information contained herein is based on rawinsonde observation and/or
numerical weather prediction model data taken near the Air Force Academy
in Colorado Springs, Colorado at

                   North Latitude:  38 deg 58 min 48.000 sec
                   West Longitude: 104 deg 49 min 12.000 sec
                   Elevation: 6572 feet (2003 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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