Soaring Guidance
Issued by NWS Denver/Boulder, CO

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000
UXUS97 KBOU 241249
SRGBOU

Soaring Forecast
National Weather Service Denver/Boulder, Colorado
0648 MDT Monday, April 24, 2017

This forecast is for Monday, April 24, 2017:

If the trigger temperature of 63.8 F/17.7 C is reached...then
   Thermal Soaring Index....................... Good
   Maximum rate of lift........................ 475 ft/min (2.4 m/s)
   Maximum height of thermals.................. 15218 ft MSL (9933 ft AGL)

Forecast maximum temperature................... 71.0 F/22.1 C
Time of trigger temperature.................... 1045 MDT
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................. 12181 ft MSL (6896 ft AGL)
Thermal soaring outlook for Tuesday 04/25...... Fair

Wave Soaring Index............................. Poor
Wave Soaring Index trend (to 1800 MDT)......... Little change
Height of stable layer (12-18K ft MSL)......... None
Weak PVA/NVA (through 1800 MDT)................ Weak PVA
Potential height of wave....................... 14901 ft MSL (9616 ft AGL)
Wave soaring outlook for Tuesday 04/25......... Good

Remarks... Frontal passage with weak pva will increase wave soaring with
           increased winds near the foothills. Cloudiness over the next few days
           will hinder thermals in the afternoon.

Sunrise/Sunset.................... 06:08:45 / 19:46:06 MDT
Total possible sunshine........... 13 hr 37 min 21 sec (817 min 21 sec)
Altitude of sun at 12:57:36 MDT... 63.34 degrees

Upper air data from rawinsonde observation taken on 04/24/2017 at 0600 MDT

Freezing level.................. 11207 ft MSL (5922 ft AGL)
Convective condensation level... 15580 ft MSL (10295 ft AGL)
Lifted condensation level....... 15533 ft MSL (10247 ft AGL)
Lifted index.................... -2.7
K index......................... +9.6

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  -59.3 -74.7   250   66   34   0.0   0.0  100.6 213.1    45.2      M    M
 45000  -58.3 -72.9   265   52   27   4.3   2.3   77.4 171.3    34.1      M    M
 40000  -58.2 -72.8   255   58   30   2.6   1.4   54.2 129.5    21.4      M    M
 38000  -57.7 -71.9   255   59   31 -12.2  -6.7   46.3 115.4    16.6      M    M
 36000  -56.2 -69.2   255   53   27   5.0   2.7   40.0 104.0    12.7      M    M
 34000  -52.7 -62.9   250   39   20   6.2   3.4   35.6  96.1    10.0      M    M
 32000  -49.3 -56.7   250   38   19   5.0   2.7   32.1  89.9     7.7      M    M
 30000  -45.1 -49.2   250   39   20   9.3   5.1   30.0  86.1     6.3      M    M
 29000  -42.5 -44.5   250   36   19   6.2   3.4   29.6  85.2     6.0      M    M
 28000  -40.5 -40.9   245   34   17   8.3   4.5   28.4  83.1     5.2      M    M
 27000  -38.0 -36.4   240   31   16   8.4   4.6   27.7  81.9     4.7      M    M
 26000  -35.4 -31.7   240   29   15   8.4   4.6   27.3  81.1     4.4      M    M
 25000  -33.1 -27.6   235   27   14   7.7   4.3   26.6  79.9     3.9      M    M
 24000  -30.8 -23.4   240   26   13   7.7   4.2   25.9  78.6     3.4      M    M
 23000  -28.2 -18.8   250   27   14   9.0   4.9   25.4  77.8     3.0      M    M
 22000  -25.5 -13.9   255   29   15   9.0   4.9   25.2  77.3     2.8      M    M
 21000  -23.1  -9.6   260   31   16   5.8   3.2   24.6  76.3     2.3      M    M
 20000  -21.6  -6.9   265   33   17   4.0   2.2   23.0  73.4     1.0      M    M
 19500  -20.4  -4.7   260   35   18  10.2   5.6   22.6  72.6     0.6      M    M
 19000  -19.0  -2.2   260   36   19   9.9   5.4   22.6  72.6     0.6      M    M
 18500  -17.5   0.5   255   38   20   9.6   5.3   22.6  72.7     0.7      M    M
 18000  -16.0   3.2   255   39   20   9.9   5.4   22.6  72.7     0.7      M    M
 17500  -14.5   5.9   260   39   20   9.6   5.3   22.6  72.6     0.7      M    M
 17000  -13.1   8.4   260   39   20   9.6   5.3   22.5  72.5     0.6      M    M
 16500  -10.9  12.4   265   40   20   9.5   5.2   22.5  72.5     0.6      M    M
 16000   -9.5  14.9   265   41   21   8.6   4.7   22.5  72.5     0.6      M    M
 15500   -8.5  16.7   270   47   24   6.5   3.6   22.0  71.7     0.2      M    M
 15000   -7.5  18.5   270   52   27   6.6   3.6   21.5  70.7    -0.3    847  4.3
 14500   -6.6  20.1   270   50   26   6.6   3.6   21.0  69.7    -0.9    804  4.1
 14000   -5.6  21.9   270   49   25   6.7   3.7   20.5  68.8    -1.4    761  3.9
 13500   -4.7  23.5   270   46   24   6.8   3.7   19.9  67.9    -1.9    718  3.6
 13000   -3.7  25.3   270   43   22   7.2   3.9   19.5  67.1    -2.4    672  3.4
 12500   -2.6  27.3   275   40   21   7.2   3.9   19.1  66.4    -2.8    625  3.2
 12000   -1.6  29.1   275   38   19   7.2   3.9   18.7  65.7    -3.2    579  2.9
 11500   -0.5  31.1   275   35   18   7.0   3.8   18.3  64.9    -3.6    533  2.7
 11000    0.7  33.3   275   33   17   9.9   5.4   18.0  64.4    -3.9    482  2.4
 10500    2.2  36.0   270   31   16  10.2   5.6   18.1  64.6    -3.9    421  2.1
 10250    3.0  37.4   270   30   15  10.2   5.6   18.1  64.6    -3.8    390  2.0
 10000    3.8  38.8   270   29   15  10.1   5.6   18.2  64.7    -3.8    360  1.8
  9750    4.5  40.1   270   28   14   9.8   5.4   18.2  64.8    -3.8    330  1.7
  9500    5.2  41.4   270   27   14   9.6   5.3   18.2  64.7    -3.8    301  1.5
  9250    6.0  42.8   270   26   13   9.7   5.3   18.2  64.7    -3.8    272  1.4
  9000    6.7  44.1   270   25   13   9.7   5.3   18.2  64.8    -3.8    243  1.2
  8750    7.4  45.3   265   23   12   9.5   5.2   18.2  64.7    -3.9    214  1.1
  8500    8.1  46.6   265   22   11  10.1   5.6   18.2  64.7    -3.9    185  0.9
  8250    8.8  47.8   260   20   10   7.9   4.3   18.2  64.7    -3.9    156  0.8
  8000    9.1  48.4   255   19   10  -0.8  -0.4   17.7  63.9    -4.4    141  0.7
  7750    8.9  48.0   250   17    9   0.6   0.4   16.8  62.2    -5.4    140  0.7
  7500    9.3  48.7   240   16    8   8.4   4.6   16.5  61.7    -5.7    121  0.6
  7250    9.9  49.8   235   15    8   8.9   4.9   16.4  61.6    -5.8     94  0.5
  7000   10.6  51.1   225   14    7   8.7   4.8   16.4  61.4    -5.9     67  0.3
  6750   11.2  52.2   220   13    7   8.9   4.9   16.3  61.3    -6.0     41  0.2
  6500   11.8  53.2   220   13    7   8.5   4.7   16.2  61.2    -6.1     14  0.1
  6250   12.5  54.5   215   12    6   9.8   5.4   16.1  61.0    -6.2      M    M
  6000   13.1  55.6   210   12    6   5.2   2.8   16.1  60.9    -6.3      M    M
  5750   13.1  55.6   200    8    4  -4.3  -2.3   15.3  59.6    -7.1      M    M
  5500   12.5  54.5   170    5    3  -5.9  -3.2   14.1  57.5    -8.4      M    M

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

           04/24/2017 at 0900 MDT          |       04/24/2017 at 1200 MDT
                                           |
K index... +11.4  LI... +3.2               | K index... +4.6  LI... +2.3
CAPE... 0.0  CIN... 0.0                    | CAPE... 0.0  CIN... 0.0
                                           |
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 -58.0 -72.4  260  40 20   0.3   0.1 | -58.0 -72.4  260  38 20  -0.8  -0.5
 45000 -57.6 -71.7  265  55 28   0.6   0.3 | -59.3 -74.7  265  58 30  -0.8  -0.4
 40000 -61.0 -77.8  270  59 30  -2.4  -1.3 | -62.1 -79.8  270  68 35  -1.9  -1.0
 38000 -60.8 -77.4  270  60 31   4.7   2.6 | -61.1 -78.0  270  70 36   5.8   3.2
 36000 -57.6 -71.7  275  60 31   4.7   2.6 | -57.6 -71.7  275  71 37   5.8   3.2
 34000 -54.3 -65.7  275  60 31   9.2   5.0 | -53.9 -65.0  275  71 37   9.2   5.0
 32000 -49.0 -56.2  275  56 29   8.9   4.9 | -48.6 -55.5  275  67 34   8.9   4.9
 30000 -43.6 -46.5  275  53 27   8.6   4.7 | -43.3 -45.9  275  61 31   9.1   5.0
 29000 -41.0 -41.8  275  51 26   8.6   4.7 | -40.5 -40.9  270  56 29   9.1   5.0
 28000 -38.5 -37.3  275  49 25   8.6   4.7 | -37.1 -34.8  270  51 26   9.1   5.0
 27000 -35.9 -32.6  275  48 25   8.6   4.7 | -34.4 -29.9  270  46 24   8.4   4.6
 26000 -33.4 -28.1  280  45 23   8.4   4.6 | -32.1 -25.8  265  43 22   7.9   4.4
 25000 -30.9 -23.6  280  43 22   8.4   4.6 | -29.7 -21.5  265  41 21   7.9   4.4
 24000 -28.3 -18.9  280  40 21   8.4   4.6 | -27.3 -17.1  265  38 20   7.9   4.3
 23000 -26.0 -14.8  280  38 20   7.8   4.3 | -25.1 -13.2  265  37 19   7.5   4.1
 22000 -23.6 -10.5  285  37 19   7.8   4.3 | -22.9  -9.2  265  36 18   7.5   4.1
 21000 -21.3  -6.3  285  35 18   7.6   4.2 | -20.6  -5.1  270  34 18   7.1   3.9
 20000 -19.1  -2.4  285  34 17   7.2   4.0 | -18.7  -1.7  270  33 17   6.6   3.6
 19500 -18.0  -0.4  285  33 17   7.2   4.0 | -17.7   0.1  270  33 17   6.6   3.6
 19000 -16.9   1.6  285  32 17   7.2   4.0 | -16.7   1.9  270  32 17   6.6   3.6
 18500 -15.8   3.6  285  32 16   7.2   4.0 | -15.7   3.7  270  32 16   6.6   3.6
 18000 -14.4   6.1  285  31 16   6.4   3.5 | -14.7   5.5  275  33 17   6.7   3.7
 17500 -13.4   7.9  285  31 16   6.4   3.5 | -13.7   7.3  275  35 18   6.7   3.7
 17000 -12.5   9.5  285  30 16   6.7   3.7 | -12.7   9.1  280  36 18   6.5   3.5
 16500 -11.5  11.3  285  30 16   6.7   3.7 | -11.7  10.9  280  36 19   6.4   3.5
 16000 -10.5  13.1  285  30 15   6.8   3.7 | -10.7  12.7  275  36 19   6.4   3.5
 15500  -9.5  14.9  285  29 15   6.8   3.7 |  -9.8  14.4  275  37 19   6.3   3.4
 15000  -8.5  16.7  285  29 15   6.7   3.7 |  -8.4  16.9  275  38 19   6.2   3.4
 14500  -7.5  18.5  285  28 15   6.6   3.6 |  -7.5  18.5  275  37 19   6.1   3.4
 14000  -6.6  20.1  285  28 14   6.6   3.6 |  -6.7  19.9  275  36 18   6.5   3.5
 13500  -5.6  21.9  285  27 14   6.6   3.6 |  -5.7  21.7  275  34 18   7.1   3.9
 13000  -4.7  23.5  285  26 13   6.5   3.6 |  -4.7  23.5  275  32 16   7.1   3.9
 12500  -3.8  25.2  290  25 13   6.1   3.3 |  -3.7  25.3  270  29 15   6.4   3.5
 12000  -2.9  26.8  290  24 12   6.2   3.4 |  -2.8  27.0  270  27 14   6.5   3.6
 11500  -1.9  28.6  295  24 12   7.7   4.2 |  -1.8  28.8  270  23 12   7.0   3.8
 11000  -0.8  30.6  295  24 12   7.5   4.1 |  -0.9  30.4  270  20 10   6.9   3.8
 10500   0.2  32.4  295  25 13   5.9   3.2 |   0.1  32.2  270  16  8   6.2   3.4
 10250   0.6  33.1  300  25 13   6.0   3.3 |   0.6  33.1  270  14  7   6.9   3.8
 10000   1.0  33.8  300  25 13   6.4   3.5 |   1.1  34.0  275  12  6   8.1   4.4
  9750   1.6  34.9  305  25 13   7.8   4.3 |   1.7  35.1  275  10  5   8.6   4.7
  9500   2.2  36.0  305  24 12   8.4   4.6 |   2.3  36.1  280   9  4   8.6   4.7
  9250   2.8  37.0  305  23 12   8.7   4.8 |   3.0  37.4  290   7  4   8.7   4.8
  9000   3.4  38.1  310  22 11   7.1   3.9 |   3.6  38.5  300   6  3   7.9   4.3
  8750   3.9  39.0  310  22 11   6.6   3.6 |   4.2  39.6  305   6  3   8.7   4.8
  8500   4.5  40.1  310  22 11   8.0   4.4 |   4.9  40.8  305   6  3  10.2   5.6
  8250   5.0  41.0  310  21 11   7.3   4.0 |   5.6  42.1  305   6  3   9.2   5.0
  8000   5.6  42.1  310  21 11   8.5   4.6 |   6.4  43.5  310   6  3  12.0   6.6
  7750   6.2  43.2  310  21 11   7.6   4.2 |   7.3  45.1  310   6  3  11.6   6.4
  7500   6.7  44.1  310  20 11   5.9   3.2 |   8.0  46.4  310   6  3   8.7   4.8
  7250   7.1  44.8  310  20 10   6.6   3.6 |   8.7  47.7  310   6  3   9.5   5.2
  7000   7.7  45.9  310  19 10   8.2   4.5 |   9.4  48.9  310   6  3   9.5   5.2
  6750   8.3  46.9  310  17  9   8.8   4.8 |  10.2  50.4  310   6  3   9.9   5.4
  6500   8.9  48.0  310  15  8   7.9   4.4 |  10.9  51.6  310   6  3  10.0   5.5
  6250   9.5  49.1  305  14  7   9.2   5.0 |  11.6  52.9  315   5  3  10.2   5.6
  6000  10.2  50.4  305  13  7  10.4   5.7 |  12.4  54.3  315   5  3  10.8   5.9
  5750  11.0  51.8  305  12  6  11.0   6.1 |  13.3  55.9  315   5  3  11.4   6.2
  5500  12.0  53.6  305  11  6  15.9   8.7 |  14.3  57.7  315   5  3  19.7  10.8

           04/24/2017 at 1500 MDT          |       04/24/2017 at 1800 MDT
                                           |
K index... +24.2  LI... -0.3               | K index... +26.4  LI... -0.5
CAPE... +5.9  CIN... -19.7                 | CAPE... +9.6  CIN... -28.5
                                           |
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 -57.8 -72.0  265  33 17  -0.9  -0.5 | -58.7 -73.7  265  33 17   0.2   0.1
 45000 -59.2 -74.6  265  55 28  -0.9  -0.5 | -58.4 -73.1  270  46 24   0.3   0.2
 40000 -61.8 -79.2  275  76 39  -1.8  -1.0 | -60.4 -76.7  270  77 40  -1.4  -0.8
 38000 -60.9 -77.6  275  82 42   6.3   3.5 | -59.5 -75.1  265  84 43   5.9   3.3
 36000 -56.6 -69.9  270  86 44   6.3   3.5 | -55.9 -68.6  265  83 43   5.9   3.2
 34000 -52.5 -62.5  265  85 44   9.0   4.9 | -51.7 -61.1  260  80 41   7.7   4.2
 32000 -47.1 -52.8  265  68 35   8.9   4.9 | -47.2 -53.0  265  73 37   7.6   4.2
 30000 -41.8 -43.2  260  54 28   8.6   4.7 | -42.5 -44.5  265  65 33   8.8   4.9
 29000 -39.2 -38.6  260  54 28   8.7   4.8 | -39.8 -39.6  260  61 31   8.8   4.9
 28000 -36.6 -33.9  260  53 28   8.7   4.8 | -37.2 -35.0  260  57 29   8.9   4.9
 27000 -34.0 -29.2  265  53 27   8.4   4.6 | -34.5 -30.1  255  53 27   8.7   4.8
 26000 -31.7 -25.1  265  53 27   7.7   4.2 | -32.2 -26.0  255  48 25   7.7   4.2
 25000 -29.4 -20.9  260  53 27   7.7   4.2 | -29.9 -21.8  255  43 22   7.8   4.3
 24000 -27.1 -16.8  260  53 27   7.9   4.3 | -27.6 -17.7  255  38 19   7.8   4.3
 23000 -25.2 -13.4  260  52 27   5.9   3.3 | -25.4 -13.7  260  39 20   7.0   3.8
 22000 -23.5 -10.3  260  51 26   6.0   3.3 | -23.3  -9.9  265  43 22   7.0   3.8
 21000 -21.7  -7.1  260  50 26   6.1   3.4 | -21.3  -6.3  270  47 24   7.0   3.9
 20000 -19.8  -3.6  260  48 25   6.7   3.7 | -19.2  -2.6  265  46 24   7.1   3.9
 19500 -18.8  -1.8  255  47 24   6.7   3.7 | -18.1  -0.6  265  44 23   7.1   3.9
 19000 -17.8  -0.0  255  46 24   6.7   3.7 | -17.1   1.2  265  43 22   7.1   3.9
 18500 -16.8   1.8  255  45 23   6.7   3.6 | -16.0   3.2  265  42 22   7.1   3.9
 18000 -15.2   4.6  255  42 22   7.7   4.2 | -14.9   5.2  265  40 21   7.5   4.1
 17500 -14.1   6.6  250  40 20   7.8   4.3 | -13.3   8.1  260  38 19   7.5   4.1
 17000 -12.9   8.8  250  37 19   7.8   4.3 | -12.2  10.0  255  36 18   7.5   4.1
 16500 -11.8  10.8  250  35 18   7.9   4.3 | -11.1  12.0  250  34 17   7.6   4.1
 16000 -10.7  12.7  250  33 17   7.4   4.0 | -10.0  14.0  245  32 16   7.5   4.1
 15500  -9.6  14.7  245  30 16   7.3   4.0 |  -8.9  16.0  245  31 16   7.5   4.1
 15000  -8.5  16.7  245  28 15   7.5   4.1 |  -7.8  18.0  240  30 15   7.4   4.1
 14500  -7.4  18.7  245  26 14   7.7   4.2 |  -6.8  19.8  240  30 15   7.1   3.9
 14000  -6.3  20.7  245  24 13   7.9   4.3 |  -5.8  21.6  240  30 16   7.1   3.9
 13500  -5.0  23.0  240  23 12   9.0   4.9 |  -4.8  23.4  235  29 15   6.7   3.7
 13000  -3.6  25.5  240  21 11   8.9   4.9 |  -3.8  25.2  225  27 14   6.8   3.7
 12500  -2.3  27.9  235  20 10   8.6   4.7 |  -2.8  27.0  220  24 12   6.4   3.5
 12000  -1.0  30.2  230  19 10   8.7   4.8 |  -1.9  28.6  220  20 10   6.2   3.4
 11500   0.2  32.4  225  17  9   8.0   4.4 |  -0.9  30.4  215  16  8   8.0   4.4
 11000   1.4  34.5  215  15  8   8.1   4.5 |   0.4  32.7  205  13  7   7.9   4.3
 10500   2.6  36.7  205  12  6   7.4   4.0 |   1.7  35.1  190  12  6   9.9   5.4
 10250   3.1  37.6  200  10  5   7.4   4.0 |   2.4  36.3  180  11  6   9.4   5.2
 10000   3.6  38.5  195   8  4   7.0   3.9 |   3.0  37.4  175  11  6   8.5   4.6
  9750   4.2  39.6  185   7  3   8.2   4.5 |   3.7  38.7  170  11  5   9.1   5.0
  9500   4.8  40.6  175   5  3   9.1   5.0 |   4.4  39.9  165  11  5   9.9   5.4
  9250   5.5  41.9  165   4  2   8.8   4.8 |   5.1  41.2  155  11  5  10.1   5.5
  9000   6.1  43.0  150   4  2   8.8   4.8 |   5.8  42.4  145  11  6   6.7   3.7
  8750   6.8  44.2  145   4  2  10.0   5.5 |   6.2  43.2  140  11  6   7.3   4.0
  8500   7.6  45.7  145   3  2  10.5   5.8 |   6.9  44.4  135  12  6  10.2   5.6
  8250   8.4  47.1  140   3  2  11.3   6.2 |   7.7  45.9  130  13  7  10.1   5.5
  8000   9.2  48.6  135   3  2   7.7   4.2 |   8.4  47.1  125  14  7   7.7   4.2
  7750   9.6  49.3  135   3  1   7.5   4.1 |   8.8  47.8  120  15  8   7.5   4.1
  7500  10.4  50.7  130   3  1  11.0   6.0 |   9.6  49.3  120  15  8  10.1   5.5
  7250  11.2  52.2  130   3  1  10.0   5.5 |  10.3  50.5  115  15  8   9.3   5.1
  7000  11.9  53.4  125   2  1  10.4   5.7 |  11.0  51.8  115  15  8   9.9   5.4
  6750  12.7  54.9  120   2  1  10.0   5.5 |  11.7  53.1  115  15  8  10.1   5.5
  6500  13.4  56.1  120   2  1   9.6   5.3 |  12.5  54.5  115  15  8   9.7   5.3
  6250  14.2  57.6  115   2  1  10.0   5.5 |  13.2  55.8  115  15  8   9.9   5.4
  6000  14.9  58.8  110   2  1  10.1   5.5 |  13.9  57.0  110  15  8   9.6   5.3
  5750  15.8  60.4  105   2  1  15.8   8.7 |  14.7  58.5  110  15  8  12.0   6.6
  5500  17.4  63.3  100   2  1  26.0  14.3 |  15.8  60.4  110  13  7  16.6   9.1
________________________________________________________________________________

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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