Soaring Guidance
Issued by NWS Denver/Boulder, CO

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25
000
UXUS97 KBOU 201318
SRGBOU

Soaring Forecast
National Weather Service Denver/Boulder, Colorado
0617 MST Saturday, December 20, 2014

This forecast is for Saturday, December 20, 2014:

If the trigger temperature of 53.4 F/11.9 C is reached...then
   Thermal Soaring Index....................... Poor
   Maximum rate of lift........................ 0 ft/min (0.0 m/s)
   Maximum height of thermals.................. 6645 ft MSL (1360 ft AGL)

Forecast maximum temperature................... 49.0 F/9.9 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................. 5815 ft MSL (530 ft AGL)
Thermal soaring outlook for Sunday 12/21....... Poor

Wave Soaring Index............................. Poor
Wave Soaring Index trend (to 1700 MST)......... Becoming good
Height of stable layer (12-18K ft MSL)......... 17371 ft MSL (12086 ft AGL)
Weak PVA/NVA (through 1700 MST)................ Weak NVA
Potential height of wave....................... 18111 ft MSL (12826 ft AGL)
Wave soaring outlook for Sunday 12/21.......... Fair

Remarks...

Sunrise/Sunset.................... 07:16:29 / 16:37:56 MST
Total possible sunshine........... 9 hr 21 min 27 sec (561 min 27 sec)
Altitude of sun at 11:57:13 MST... 26.87 degrees

Upper air data from rawinsonde observation taken on 12/20/2014 at 0500 MST

Freezing level.................. 5416 ft MSL (131 ft AGL)
Additional freezing level....... 9253 ft MSL (3968 ft AGL)
Convective condensation level... 15775 ft MSL (10490 ft AGL)
Lifted condensation level....... 13717 ft MSL (8431 ft AGL)
Lifted index.................... +7.1
K index......................... +10.1

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  -54.9 -66.8   285   19   10   7.2   4.0  111.0 231.8    57.7      M    M
 45000  -56.3 -69.3   260   42   22  -3.6  -1.9   83.7 182.7    45.1      M    M
 40000  -57.8 -72.0   275   33   17   0.2   0.1   58.0 136.3    31.6      M    M
 38000  -56.4 -69.5   280   35   18   9.5   5.2   51.1 124.0    27.9      M    M
 36000  -63.6 -82.5   275   46   24 -24.3 -13.3   31.9  89.4    15.4      M    M
 34000  -60.8 -77.4   275   57   29   8.8   4.8   26.4  79.5    12.0      M    M
 32000  -55.6 -68.1   275   51   26   8.7   4.8   25.5  77.9    11.7      M    M
 30000  -50.4 -58.7   270   41   21   9.2   5.1   24.6  76.3    11.3      M    M
 29000  -47.7 -53.9   270   39   20   9.0   4.9   24.3  75.7    11.2      M    M
 28000  -45.0 -49.0   270   37   19   9.0   4.9   23.9  75.1    11.1      M    M
 27000  -42.3 -44.1   270   36   18   9.0   4.9   23.7  74.7    11.1      M    M
 26000  -39.5 -39.1   270   34   17   8.5   4.7   23.6  74.4    11.1      M    M
 25000  -37.1 -34.8   270   32   16   9.3   5.1   22.9  73.2    10.7      M    M
 24000  -34.2 -29.6   270   29   15   9.6   5.3   22.8  73.1    10.8      M    M
 23000  -31.5 -24.7   270   26   13   8.8   4.8   22.5  72.5    10.7      M    M
 22000  -28.9 -20.0   270   22   11   8.8   4.8   22.1  71.8    10.5      M    M
 21000  -26.2 -15.2   275   19   10   8.8   4.8   21.8  71.3    10.4      M    M
 20000  -23.6 -10.5   275   15    8   8.8   4.8   21.6  70.9    10.3      M    M
 19500  -22.3  -8.1   280   15    8   8.8   4.8   21.4  70.6    10.2      M    M
 19000  -20.9  -5.6   290   16    8   8.7   4.8   21.2  70.2    10.1      M    M
 18500  -19.6  -3.3   285   16    8   7.3   4.0   21.0  69.8    10.0      M    M
 18000  -19.0  -2.2   285   16    8   2.6   1.5   20.1  68.2     9.2      M    M
 17500  -18.5  -1.3   265   14    7  -2.4  -1.3   19.0  66.2     8.2      M    M
 17000  -18.9  -2.0   230   15    8   3.7   2.0   16.1  61.0     5.7      M    M
 16500  -18.1  -0.6   235   14    7   7.9   4.4   15.4  59.8     5.1      M    M
 16000  -16.9   1.6   240   12    6   8.1   4.5   15.2  59.3     4.9      M    M
 15500  -15.6   3.9   250   10    5   8.2   4.5   14.9  58.8     4.7      M    M
 15000  -14.4   6.1   265    8    4   8.2   4.5   14.6  58.3     4.4      M    M
 14500  -13.2   8.2   290    7    4   8.2   4.5   14.4  57.9     4.2      M    M
 14000  -12.0  10.4   310    7    4   8.2   4.5   14.1  57.5     4.0      M    M
 13500  -10.8  12.6   305    6    3   8.2   4.5   13.9  56.9     3.8      M    M
 13000   -9.5  14.9   295    6    3   8.8   4.8   13.6  56.5     3.6      M    M
 12500   -8.1  17.4   275    9    5   9.6   5.2   13.6  56.4     3.6      M    M
 12000   -6.7  19.9   265   12    6   9.6   5.3   13.5  56.4     3.6      M    M
 11500   -5.2  22.6   275   13    7   9.6   5.3   13.5  56.3     3.5      M    M
 11000   -3.8  25.2   280   15    8   9.4   5.1   13.5  56.3     3.5      M    M
 10500   -2.6  27.3   285   16    8   6.4   3.5   13.1  55.6     3.2      M    M
 10250   -2.1  28.2   290   17    9   6.7   3.7   12.9  55.2     3.0      M    M
 10000   -1.6  29.1   290   18    9   7.2   3.9   12.7  54.8     2.8      M    M
  9750   -1.1  30.0   285   16    8   7.7   4.2   12.5  54.5     2.6      M    M
  9500   -0.5  31.1   280   15    7   7.5   4.1   12.3  54.2     2.5      M    M
  9250    0.0  32.0   275   13    7   7.6   4.2   12.2  53.9     2.3      M    M
  9000    0.6  33.1   265   12    6   7.6   4.1   12.0  53.6     2.2      M    M
  8750    1.2  34.2   275   12    6   7.6   4.2   11.8  53.3     2.0      M    M
  8500    1.7  35.1   280   13    6   7.6   4.2   11.7  53.0     1.8      M    M
  8250    2.3  36.1   290   13    7   7.6   4.2   11.5  52.7     1.7      M    M
  8000    2.9  37.2   295   14    7   7.6   4.1   11.3  52.4     1.5      M    M
  7750    3.4  38.1   290   13    7   7.6   4.2   11.1  52.1     1.3      M    M
  7500    4.0  39.2   280   11    6   7.4   4.1   11.0  51.8     1.2      M    M
  7250    4.5  40.1   270   11    5   8.2   4.5   10.8  51.4     1.0      M    M
  7000    5.1  41.2   260   10    5   5.3   2.9   10.6  51.2     0.8      M    M
  6750    5.3  41.5   240   10    5   1.8   1.0   10.1  50.2     0.3      M    M
  6500    5.5  41.9   225   12    6   1.5   0.8    9.5  49.1    -0.3     30  0.2
  6250    5.6  42.1   210   14    7   3.3   1.8    8.9  48.0    -0.9     18  0.1
  6000    5.7  42.3   200   17    9  -3.5  -1.9    8.3  47.0    -1.5      7  0.0
  5750    4.7  40.5   195   13    7 -25.8 -14.2    6.5  43.7    -3.3     31  0.2
  5500    1.9  35.4   185    8    4 -47.7 -26.2    3.0  37.3    -6.8    108  0.5

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

           12/20/2014 at 0800 MST          |       12/20/2014 at 1100 MST
                                           |
K index... +15.3  LI... +1.8               | K index... +17.6  LI... +2.2
CAPE... 0.0  CIN... M                      | 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 -56.5 -69.7  265  23 12  -0.4  -0.2 | -57.0 -70.6  270  24 12  -0.4  -0.2
 45000 -57.1 -70.8  270  31 16  -0.4  -0.2 | -57.6 -71.7  275  34 17  -0.4  -0.2
 40000 -57.4 -71.3  290  36 19  -0.2  -0.1 | -55.9 -68.6  290  29 15   1.4   0.8
 38000 -57.7 -71.9  290  39 20  -1.5  -0.8 | -55.3 -67.5  295  28 15  -1.5  -0.8
 36000 -58.5 -73.3  275  41 21  -1.4  -0.8 | -56.2 -69.2  290  32 16  -1.4  -0.8
 34000 -59.4 -74.9  265  45 23  -2.4  -1.3 | -57.2 -71.0  280  36 19   0.5   0.3
 32000 -55.2 -67.4  260  41 21   7.3   4.0 | -54.5 -66.1  265  36 19   4.7   2.6
 30000 -50.7 -59.3  260  36 19   8.6   4.7 | -51.5 -60.7  255  37 19   7.4   4.1
 29000 -48.1 -54.6  260  36 18   8.8   4.8 | -48.9 -56.0  260  35 18   8.7   4.8
 28000 -45.4 -49.7  260  35 18   8.8   4.8 | -46.3 -51.3  260  33 17   8.7   4.8
 27000 -42.8 -45.0  260  35 18   8.8   4.9 | -43.7 -46.7  265  31 16   8.7   4.8
 26000 -40.2 -40.4  260  33 17   8.7   4.8 | -41.1 -42.0  270  29 15   8.6   4.7
 25000 -37.6 -35.7  260  32 16   8.7   4.8 | -38.6 -37.5  275  27 14   8.6   4.7
 24000 -35.0 -31.0  260  30 16   8.8   4.8 | -36.0 -32.8  280  25 13   8.6   4.7
 23000 -32.5 -26.5  265  29 15   7.8   4.3 | -33.5 -28.3  285  25 13   8.3   4.6
 22000 -30.2 -22.4  260  28 14   7.8   4.3 | -31.0 -23.8  290  25 13   8.3   4.6
 21000 -27.9 -18.2  260  26 14   7.7   4.2 | -28.5 -19.3  295  25 13   8.3   4.5
 20000 -25.7 -14.3  260  25 13   7.2   3.9 | -26.1 -15.0  295  25 13   8.0   4.4
 19500 -24.6 -12.3  260  24 12   7.2   4.0 | -24.9 -12.8  295  25 13   8.0   4.4
 19000 -23.6 -10.5  265  23 12   7.2   4.0 | -23.7 -10.7  290  25 13   8.0   4.4
 18500 -22.5  -8.5  265  22 12   7.2   4.0 | -22.5  -8.5  290  25 13   8.0   4.4
 18000 -21.4  -6.5  265  21 11   7.5   4.1 | -21.4  -6.5  290  25 13   7.3   4.0
 17500 -20.3  -4.5  265  21 11   7.5   4.1 | -20.3  -4.5  290  24 12   7.4   4.1
 17000 -19.2  -2.6  270  20 10   7.2   4.0 | -19.2  -2.6  285  24 12   6.8   3.7
 16500 -17.6   0.3  270  18 10   7.1   3.9 | -17.7   0.1  285  23 12   6.6   3.6
 16000 -16.5   2.3  275  18  9   7.3   4.0 | -16.8   1.8  285  22 11   6.8   3.7
 15500 -15.4   4.3  275  17  9   7.3   4.0 | -15.7   3.7  280  21 11   6.8   3.7
 15000 -14.4   6.1  275  16  8   7.2   4.0 | -14.7   5.5  280  20 10   6.7   3.7
 14500 -13.3   8.1  280  15  8   7.2   4.0 | -13.8   7.2  280  19 10   6.7   3.7
 14000 -12.2  10.0  280  14  7   7.4   4.0 | -12.8   9.0  280  18  9   6.6   3.6
 13500 -11.1  12.0  280  13  7   7.5   4.1 | -11.8  10.8  275  16  8   6.6   3.6
 13000 -10.0  14.0  280  12  6   7.4   4.1 | -10.9  12.4  275  15  8   6.4   3.5
 12500  -9.0  15.8  280  11  5   7.3   4.0 | -10.0  14.0  280  13  7   6.2   3.4
 12000  -7.9  17.8  280   9  5   7.6   4.2 |  -9.1  15.6  280  12  6   7.1   3.9
 11500  -6.7  19.9  285   9  4   8.0   4.4 |  -7.9  17.8  285  11  6   8.4   4.6
 11000  -5.5  22.1  290   8  4   8.0   4.4 |  -6.6  20.1  290  10  5   9.7   5.3
 10500  -4.3  24.3  295   8  4   8.6   4.7 |  -4.9  23.2  295  10  5  11.9   6.5
 10250  -3.7  25.3  300   8  4   5.5   3.0 |  -4.1  24.6  300  10  5   7.2   4.0
 10000  -3.4  25.9  300   8  4   5.7   3.1 |  -3.8  25.2  300  10  5   6.3   3.5
  9750  -2.8  27.0  300   9  5   9.8   5.4 |  -3.0  26.6  305  10  5  11.2   6.1
  9500  -2.1  28.2  305   9  5   9.9   5.4 |  -2.2  28.0  305  11  6  11.1   6.1
  9250  -1.3  29.7  305  10  5   9.2   5.1 |  -1.4  29.5  305  11  6  10.0   5.5
  9000  -0.7  30.7  305  11  5   7.2   4.0 |  -0.8  30.6  310  12  6   7.3   4.0
  8750  -0.2  31.6  305  11  6   6.9   3.8 |  -0.2  31.6  305  12  6   7.5   4.1
  8500   0.3  32.5  305  12  6   7.5   4.1 |   0.4  32.7  305  12  6   8.8   4.8
  8250   0.9  33.6  300  12  6   7.2   4.0 |   1.0  33.8  305  13  7   7.1   3.9
  8000   1.4  34.5  300  12  6   7.1   3.9 |   1.4  34.5  300  12  6   5.3   2.9
  7750   1.9  35.4  295  12  6   5.7   3.1 |   1.8  35.2  300  12  6   4.9   2.7
  7500   2.3  36.1  295  11  6   4.6   2.5 |   2.1  35.8  300  11  6   4.5   2.4
  7250   2.6  36.7  290  11  5   4.8   2.6 |   2.5  36.5  300  10  5   4.6   2.5
  7000   3.0  37.4  285  10  5   4.2   2.3 |   2.8  37.0  300   8  4   4.7   2.6
  6750   3.3  37.9  280   9  4   5.7   3.1 |   3.2  37.8  295   6  3   4.5   2.5
  6500   3.6  38.5  270   7  4  -0.0  -0.0 |   3.5  38.3  295   5  2   3.3   1.8
  6250   3.3  37.9  260   7  4  -7.6  -4.2 |   3.7  38.7  285   4  2   2.4   1.3
  6000   2.8  37.0  245   8  4  -4.6  -2.5 |   3.9  39.0  275   3  2   2.6   1.4
  5750   2.4  36.3  235   9  5 -10.0  -5.5 |   4.0  39.2  260   3  2   1.2   0.7
  5500   0.7  33.3  225   9  5 -36.7 -20.1 |   4.0  39.2  240   3  2  -0.6  -0.3

           12/20/2014 at 1400 MST          |       12/20/2014 at 1700 MST
                                           |
K index... +17.2  LI... +1.6               | K index... +14.0  LI... +2.4
CAPE... 0.0  CIN... M                      | 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 -56.6 -69.9  285  26 13  -0.8  -0.4 | -56.4 -69.5  305  29 15  -0.5  -0.2
 45000 -57.7 -71.9  285  36 19  -0.7  -0.4 | -57.1 -70.8  305  38 19  -0.4  -0.2
 40000 -57.6 -71.7  300  34 17   0.2   0.1 | -56.9 -70.4  310  40 20   0.2   0.1
 38000 -57.5 -71.5  305  33 17   0.3   0.2 | -56.9 -70.4  315  41 21  -0.6  -0.4
 36000 -57.3 -71.1  305  37 19   0.3   0.2 | -57.3 -71.1  310  43 22  -0.6  -0.3
 34000 -57.1 -70.8  310  41 21   2.3   1.2 | -57.7 -71.9  310  46 24   2.1   1.2
 32000 -53.8 -64.8  315  44 23   5.7   3.1 | -54.0 -65.2  310  48 25   6.4   3.5
 30000 -50.3 -58.5  320  48 24   8.0   4.4 | -50.0 -58.0  310  50 26   8.0   4.4
 29000 -47.6 -53.7  325  45 23   9.0   4.9 | -47.5 -53.5  310  47 24   8.5   4.7
 28000 -44.9 -48.8  325  43 22   9.0   4.9 | -44.9 -48.8  310  43 22   8.5   4.7
 27000 -42.2 -44.0  325  40 21   9.0   5.0 | -42.4 -44.3  310  40 21   8.5   4.7
 26000 -39.6 -39.3  325  37 19   8.5   4.7 | -39.7 -39.5  305  37 19   9.1   5.0
 25000 -37.0 -34.6  330  34 18   8.5   4.7 | -37.0 -34.6  305  34 17   9.1   5.0
 24000 -34.5 -30.1  330  31 16   8.5   4.7 | -34.2 -29.6  305  31 16   9.2   5.0
 23000 -32.2 -26.0  325  26 14   7.1   3.9 | -31.8 -25.2  300  28 14   7.7   4.2
 22000 -30.0 -22.0  310  21 11   7.1   3.9 | -29.5 -21.1  295  25 13   7.6   4.2
 21000 -27.9 -18.2  290  18  9   7.1   3.9 | -27.2 -17.0  290  22 11   7.6   4.2
 20000 -25.7 -14.3  285  18  9   7.2   4.0 | -24.9 -12.8  290  21 11   7.7   4.2
 19500 -24.7 -12.5  280  18  9   7.3   4.0 | -23.7 -10.7  290  21 11   7.7   4.2
 19000 -23.6 -10.5  280  19 10   7.3   4.0 | -22.6  -8.7  290  21 11   7.7   4.2
 18500 -22.5  -8.5  280  19 10   7.3   4.0 | -21.4  -6.5  290  21 11   7.8   4.3
 18000 -21.5  -6.7  280  19 10   6.9   3.8 | -20.3  -4.5  290  21 11   6.5   3.6
 17500 -20.4  -4.7  280  20 10   7.0   3.8 | -19.4  -2.9  290  21 11   6.7   3.7
 17000 -19.4  -2.9  280  21 11   7.0   3.9 | -18.0  -0.4  290  21 11   5.8   3.2
 16500 -17.9  -0.2  280  22 11   7.0   3.8 | -17.1   1.2  290  21 11   5.9   3.2
 16000 -16.8   1.8  280  23 12   7.7   4.2 | -16.2   2.8  290  21 11   6.7   3.7
 15500 -15.6   3.9  280  24 12   7.8   4.3 | -15.2   4.6  285  22 11   6.8   3.7
 15000 -14.5   5.9  280  25 13   7.7   4.2 | -14.2   6.4  285  23 12   6.6   3.6
 14500 -13.4   7.9  280  26 13   7.6   4.2 | -13.3   8.1  285  23 12   6.6   3.6
 14000 -12.2  10.0  285  26 13   7.5   4.1 | -12.3   9.9  280  24 12   6.6   3.6
 13500 -11.1  12.0  285  25 13   7.4   4.1 | -11.4  11.5  280  23 12   6.7   3.7
 13000 -10.0  14.0  285  25 13   7.4   4.0 | -10.4  13.3  280  22 11   6.9   3.8
 12500  -8.9  16.0  285  23 12   7.3   4.0 |  -9.3  15.3  280  20 10   7.3   4.0
 12000  -7.9  17.8  290  21 11   7.3   4.0 |  -8.3  17.1  275  17  9   7.2   4.0
 11500  -6.8  19.8  290  19 10   7.4   4.1 |  -7.2  19.0  270  15  8   7.1   3.9
 11000  -5.7  21.7  295  17  9   7.0   3.8 |  -6.2  20.8  265  12  6   7.0   3.8
 10500  -4.7  23.5  300  15  8   6.4   3.5 |  -5.2  22.6  255  11  6   7.0   3.8
 10250  -4.3  24.3  300  14  7   5.6   3.1 |  -4.6  23.7  250  10  5   5.8   3.2
 10000  -3.8  25.2  305  13  7   9.5   5.2 |  -4.1  24.6  250  10  5  10.3   5.6
  9750  -3.0  26.6  310  12  6  10.0   5.5 |  -3.2  26.2  245   9  4  10.8   5.9
  9500  -2.4  27.7  310  12  6   6.8   3.7 |  -2.6  27.3  245   8  4   6.7   3.7
  9250  -1.8  28.8  315  11  6   7.6   4.2 |  -2.1  28.2  240   7  4   7.6   4.2
  9000  -1.3  29.7  315  10  5   7.0   3.8 |  -1.5  29.3  235   6  3   6.8   3.7
  8750  -0.8  30.6  320  10  5   7.3   4.0 |  -1.0  30.2  235   5  3   7.4   4.1
  8500  -0.2  31.6  325   9  5   7.8   4.3 |  -0.4  31.3  235   4  2   8.0   4.4
  8250   0.4  32.7  325   8  4   7.4   4.1 |   0.2  32.4  230   3  2   7.8   4.3
  8000   0.9  33.6  330   7  4   6.9   3.8 |   0.7  33.3  225   2  1   7.7   4.2
  7750   1.4  34.5  330   6  3   6.1   3.4 |   1.3  34.3  205   2  1   7.0   3.9
  7500   1.8  35.2  335   5  3   5.7   3.1 |   1.8  35.2  180   1  1   6.5   3.6
  7250   2.2  36.0  340   4  2   5.8   3.2 |   2.3  36.1  145   1  1   7.2   4.0
  7000   2.7  36.9  355   3  1   5.8   3.2 |   2.9  37.2  135   2  1   7.7   4.2
  6750   3.1  37.6  030   2  1   5.5   3.0 |   3.5  38.3  130   2  1   7.8   4.3
  6500   3.5  38.3  080   2  1   6.7   3.7 |   4.0  39.2  130   3  2   7.2   3.9
  6250   4.1  39.4  100   2  1   8.6   4.7 |   4.5  40.1  135   3  2   5.6   3.1
  6000   4.8  40.6  110   2  1   8.6   4.7 |   4.9  40.8  140   4  2   6.2   3.4
  5750   5.4  41.7  115   2  1   9.1   5.0 |   5.3  41.5  145   4  2   3.6   2.0
  5500   6.1  43.0  115   2  1  11.8   6.5 |   5.2  41.4  150   4  2  -6.6  -3.6
________________________________________________________________________________

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



USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.