Soaring Guidance
Issued by NWS Pueblo, CO

Home | Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14
000
UXUS97 KPUB 111131
SRGPUB

Soaring Forecast
National Weather Service Pueblo, Colorado
0430 MST Wednesday, January 11, 2017

This forecast is for Wednesday, January 11, 2017:

If the trigger temperature of 58.5 F/14.7 C is reached...then
   Thermal Soaring Index....................... Poor
   Maximum rate of lift........................ 129 ft/min (0.7 m/s)
   Maximum height of thermals.................. 8983 ft MSL (1812 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....... Overcast thin high
Surface winds during soaring window............ Between 20 mph and 30 mph
Height of the -3 thermal index................. 8140 ft MSL (969 ft AGL)
Thermal soaring outlook for Thursday 01/12..... Fair

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

Remarks...

Sunrise/Sunset.................... 07:17:07 / 16:57:18 MST
Total possible sunshine........... 9 hr 40 min 11 sec (580 min 11 sec)
Altitude of sun at 12:07:05 MST... 29.43 degrees

Upper air data from numerical model forecast valid on 01/11/2017 at 0500 MST

Freezing level.................. 12206 ft MSL (5035 ft AGL)
Convective condensation level... 18024 ft MSL (10853 ft AGL)
Lifted condensation level....... 14764 ft MSL (7593 ft AGL)
Lifted index.................... +5.8
K index......................... +3.9

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  -68.8 -91.8   260   80   41   4.6   2.5      M     M       M      M    M
 45000  -62.0 -79.6   270   80   41   4.7   2.6      M     M       M      M    M
 40000  -60.6 -77.1   270  103   53   0.6   0.3      M     M       M      M    M
 38000  -59.0 -74.2   270  111   57   5.0   2.8      M     M       M      M    M
 36000  -56.0 -68.8   270  113   58   5.0   2.8      M     M       M      M    M
 34000  -52.8 -63.0   270  114   59   7.5   4.1      M     M       M      M    M
 32000  -48.3 -54.9   270  103   53   7.6   4.2      M     M       M      M    M
 30000  -43.7 -46.7   270   92   48   8.0   4.4   26.1  79.0    12.8      M    M
 29000  -41.4 -42.5   270   88   45   7.9   4.3   25.2  77.4    12.2      M    M
 28000  -39.0 -38.2   270   84   43   7.9   4.3   24.5  76.1    11.8      M    M
 27000  -36.7 -34.1   275   79   41   7.9   4.3   23.9  75.0    11.5      M    M
 26000  -34.3 -29.7   275   76   39   7.8   4.3   23.1  73.6    11.0      M    M
 25000  -32.0 -25.6   275   74   38   7.9   4.3   22.4  72.3    10.6      M    M
 24000  -29.0 -20.2   275   71   37   7.8   4.3   21.6  70.9    10.1      M    M
 23000  -26.6 -15.9   275   69   36   7.9   4.4   20.9  69.7     9.6      M    M
 22000  -24.3 -11.7   275   67   35   7.9   4.4   20.3  68.5     9.2      M    M
 21000  -21.9  -7.4   275   65   34   8.1   4.4   19.7  67.5     8.8      M    M
 20000  -19.4  -2.9   275   62   32   8.3   4.5   19.1  66.4     8.4      M    M
 19500  -18.2  -0.8   275   60   31   8.3   4.5   18.9  65.9     8.2      M    M
 19000  -17.0   1.4   270   59   30   8.3   4.5   18.6  65.5     8.0      M    M
 18500  -15.7   3.7   270   57   29   8.2   4.5   18.4  65.2     7.9      M    M
 18000  -14.6   5.7   270   56   29   7.5   4.1   18.1  64.6     7.6      M    M
 17500  -13.4   7.9   270   54   28   7.6   4.2   17.7  63.9     7.3      M    M
 17000  -12.3   9.9   270   52   27   8.5   4.7   17.4  63.4     7.1      M    M
 16500  -11.0  12.2   270   50   26   8.8   4.8   17.3  63.1     6.9      M    M
 16000   -9.7  14.5   265   47   24   8.8   4.8   17.1  62.8     6.8      M    M
 15500   -8.4  16.9   265   46   24   8.8   4.8   17.0  62.5     6.7      M    M
 15000   -7.1  19.2   265   46   23   8.9   4.9   16.8  62.2     6.6      M    M
 14500   -5.8  21.6   265   46   24   7.9   4.3   16.6  61.8     6.4      M    M
 14000   -4.7  23.5   265   46   24   8.0   4.4   16.3  61.3     6.1      M    M
 13500   -3.5  25.7   265   46   24   8.1   4.5   16.0  60.8     5.9      M    M
 13000   -2.3  27.9   265   44   23   8.2   4.5   15.8  60.4     5.7      M    M
 12500   -1.1  30.0   265   42   22   9.4   5.2   15.5  60.0     5.5      M    M
 12000    0.3  32.5   260   39   20   8.0   4.4   15.4  59.8     5.4      M    M
 11750    0.9  33.6   255   38   19   8.0   4.4   15.3  59.5     5.3      M    M
 11500    1.5  34.7   255   36   18   8.5   4.7   15.2  59.3     5.1      M    M
 11250    2.2  36.0   255   35   18   9.9   5.4   15.1  59.2     5.1      M    M
 11000    2.9  37.2   255   35   18   7.1   3.9   15.1  59.2     5.1      M    M
 10750    3.2  37.8   255   34   18   4.7   2.6   14.7  58.5     4.7      M    M
 10500    3.6  38.5   255   34   18   4.3   2.4   14.3  57.8     4.4      M    M
 10250    3.8  38.8   260   37   19   3.2   1.8   13.9  56.9     3.9      M    M
 10000    4.1  39.4   260   39   20   3.5   1.9   13.4  56.1     3.4      M    M
  9750    4.3  39.7   265   44   23  -0.7  -0.4   12.2  53.9     2.2      M    M
  9500    4.2  39.6   265   47   24  -1.6  -0.9   11.3  52.3     1.4      M    M
  9250    4.1  39.4   265   51   26  -1.4  -0.8   10.4  50.8     0.5      M    M
  9000    4.0  39.2   270   54   28  -1.3  -0.7    9.6  49.3    -0.3    227  1.2
  8750    3.9  39.0   270   59   30  -1.5  -0.8    8.7  47.7    -1.2    224  1.1
  8500    3.7  38.7   270   55   28  -1.9  -1.1    7.9  46.1    -2.1    221  1.1
  8250    3.6  38.5   270   51   26  -1.6  -0.9    7.0  44.6    -2.9    218  1.1
  8000    3.4  38.1   270   47   24  -2.3  -1.3    6.1  43.0    -3.8    215  1.1
  7750    3.2  37.8   270   42   22  -2.7  -1.5    5.2  41.3    -4.8    215  1.1
  7500    3.0  37.4   270   33   17  -1.3  -0.7    4.3  39.7    -5.7    212  1.1
  7250    2.8  37.0   270   24   12  -4.4  -2.4    3.4  38.1    -6.6    210  1.1
  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 * * * * * *

           01/11/2017 at 0800 MST          |       01/11/2017 at 1100 MST
                                           |
K index... -10.8  LI... +3.6               | K index... -9.8  LI... +2.9
CAPE... 0.0  CIN... -0.7                   | CAPE... 0.0  CIN... -1.1
                                           |
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 -66.8 -88.2  250  63 32   3.2   1.8 | -67.6 -89.7  250  64 33   3.0   1.6
 45000 -62.0 -79.6  255  68 35   3.2   1.8 | -63.1 -81.6  260  72 37   3.0   1.6
 40000 -60.5 -76.9  265  96 49   0.8   0.4 | -58.2 -72.8  265  90 47   3.3   1.8
 38000 -59.3 -74.7  265 106 55   4.8   2.7 | -56.4 -69.5  265 100 51   2.6   1.5
 36000 -56.0 -68.8  265 111 57   4.9   2.7 | -54.6 -66.3  265 115 59   2.6   1.4
 34000 -53.0 -63.4  265 115 59   5.7   3.1 | -53.0 -63.4  265 129 66   5.4   3.0
 32000 -49.4 -56.9  265 108 56   6.0   3.3 | -48.7 -55.7  265 122 63   7.2   3.9
 30000 -45.8 -50.4  265 101 52   7.6   4.1 | -44.4 -47.9  265 114 59   6.2   3.4
 29000 -43.4 -46.1  265  96 50   7.9   4.3 | -42.8 -45.0  265 107 55   5.4   3.0
 28000 -41.1 -42.0  265  91 47   7.9   4.3 | -41.1 -42.0  265  99 51   5.4   3.0
 27000 -38.7 -37.7  265  87 45   7.8   4.3 | -39.5 -39.1  265  91 47   5.4   3.0
 26000 -36.3 -33.3  265  83 43   8.3   4.6 | -37.4 -35.3  265  86 44   8.1   4.5
 25000 -33.8 -28.8  265  81 42   8.3   4.6 | -35.0 -31.0  265  83 43   8.2   4.5
 24000 -31.3 -24.3  265  79 41   8.4   4.6 | -32.5 -26.5  265  80 41   8.2   4.5
 23000 -28.2 -18.8  265  76 39   8.5   4.7 | -29.4 -20.9  260  74 38   8.4   4.6
 22000 -25.6 -14.1  270  74 38   8.5   4.7 | -26.9 -16.4  260  67 34   8.4   4.6
 21000 -23.0  -9.4  270  72 37   8.7   4.7 | -24.4 -11.9  260  60 31   8.4   4.6
 20000 -20.4  -4.7  270  70 36   9.0   4.9 | -21.9  -7.4  260  57 29   8.5   4.7
 19500 -19.0  -2.2  270  69 36   9.0   4.9 | -20.6  -5.1  260  56 29   8.5   4.7
 19000 -17.7   0.1  270  68 35   9.0   4.9 | -19.3  -2.7  260  55 28   8.5   4.7
 18500 -16.3   2.7  270  67 34   9.0   4.9 | -18.0  -0.4  260  53 27   8.6   4.7
 18000 -15.1   4.8  270  65 33   7.3   4.0 | -16.9   1.6  265  52 27   6.9   3.8
 17500 -14.0   6.8  270  62 32   7.5   4.1 | -15.8   3.6  265  51 26   7.1   3.9
 17000 -12.9   8.8  270  60 31   7.0   3.8 | -14.7   5.5  265  50 26   7.5   4.1
 16500 -11.9  10.6  275  57 29   6.8   3.7 | -13.6   7.5  265  46 24   7.8   4.3
 16000 -10.9  12.4  275  55 28   6.7   3.6 | -12.4   9.7  265  42 22   7.7   4.2
 15500 -10.0  14.0  275  54 28   5.9   3.2 | -11.4  11.5  265  43 22   6.6   3.6
 15000  -9.1  15.6  275  53 27   5.8   3.2 | -10.4  13.3  265  46 24   6.5   3.6
 14500  -8.2  17.2  275  51 26   7.3   4.0 |  -9.3  15.3  265  48 24   7.7   4.2
 14000  -7.1  19.2  275  49 25   7.2   3.9 |  -8.2  17.2  265  48 25   7.6   4.2
 13500  -6.0  21.2  275  46 24   8.3   4.5 |  -7.1  19.2  265  49 25   7.6   4.1
 13000  -4.8  23.4  270  44 23   8.5   4.7 |  -6.0  21.2  265  49 25   7.6   4.2
 12500  -3.5  25.7  270  42 22  10.1   5.6 |  -4.8  23.4  270  49 25   9.6   5.3
 12000  -2.0  28.4  265  40 21   9.2   5.1 |  -3.6  25.5  270  49 25   6.2   3.4
 11750  -1.3  29.7  265  39 20   9.2   5.1 |  -3.1  26.4  270  49 25   5.8   3.2
 11500  -0.6  30.9  265  38 19  10.0   5.5 |  -2.7  27.1  270  49 25   7.5   4.1
 11250   0.2  32.4  265  38 19  11.3   6.2 |  -2.0  28.4  270  49 25   9.1   5.0
 11000   1.0  33.8  265  37 19   9.3   5.1 |  -1.4  29.5  270  48 25   8.3   4.6
 10750   1.6  34.9  265  37 19   7.2   4.0 |  -0.8  30.6  270  47 24   7.8   4.3
 10500   2.1  35.8  265  37 19   7.9   4.3 |  -0.2  31.6  270  46 24   8.0   4.4
 10250   2.7  36.9  265  37 19   8.1   4.4 |   0.4  32.7  270  45 23   8.2   4.5
 10000   3.3  37.9  265  38 20   8.3   4.5 |   1.0  33.8  270  45 23   8.2   4.5
  9750   3.9  39.0  265  39 20   5.4   3.0 |   1.6  34.9  270  44 23   7.6   4.2
  9500   3.9  39.0  265  43 22  -1.4  -0.8 |   2.2  36.0  270  44 23   2.8   1.5
  9250   3.9  39.0  270  46 24  -0.6  -0.3 |   2.5  36.5  270  44 23   3.6   2.0
  9000   3.8  38.8  270  49 25  -2.1  -1.1 |   2.7  36.9  265  45 23   2.4   1.3
  8750   3.5  38.3  270  52 27  -3.3  -1.8 |   2.8  37.0  265  46 24   3.3   1.8
  8500   3.3  37.9  270  49 25  -2.8  -1.5 |   3.1  37.6  265  43 22   4.9   2.7
  8250   3.0  37.4  270  47 24  -3.0  -1.6 |   3.4  38.1  265  39 20   4.5   2.5
  8000   2.8  37.0  265  44 22  -2.5  -1.4 |   3.8  38.8  265  36 18   4.6   2.5
  7750   2.7  36.9  265  39 20  -0.4  -0.2 |   4.2  39.6  260  32 17   8.7   4.7
  7500   2.7  36.9  265  31 16   1.7   0.9 |   5.1  41.2  260  27 14  15.6   8.6
  7250   2.8  37.0  265  23 12  -1.7  -0.9 |   6.0  42.8  260  21 11   3.2   1.8
  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

           01/11/2017 at 1400 MST          |       01/11/2017 at 1700 MST
                                           |
K index... -6.0  LI... +2.0                | K index... +2.2  LI... +1.3
CAPE... 0.0  CIN... -1.1                   | CAPE... 0.0  CIN... -24.2
                                           |
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 -67.7 -89.9  250  62 32   3.6   2.0 | -67.7 -89.9  245  61 31   4.3   2.4
 45000 -62.0 -79.6  255  63 32   3.6   2.0 | -61.2 -78.2  250  74 38   4.3   2.4
 40000 -58.0 -72.4  255  88 46   2.5   1.4 | -57.0 -70.6  255  86 44   2.4   1.3
 38000 -56.5 -69.7  260 100 52   2.6   1.4 | -55.5 -67.9  255  93 48   2.4   1.3
 36000 -54.9 -66.8  260 114 59   2.6   1.4 | -54.1 -65.4  255 106 55   2.4   1.3
 34000 -53.4 -64.1  255 128 66   3.2   1.8 | -52.6 -62.7  255 119 61   2.3   1.2
 32000 -49.2 -56.6  255 126 65   7.3   4.0 | -49.2 -56.6  255 115 59   6.1   3.4
 30000 -44.8 -48.6  255 123 63   7.3   4.0 | -45.5 -49.9  255 109 56   6.2   3.4
 29000 -42.8 -45.0  255 119 61   6.8   3.7 | -43.6 -46.5  255 105 54   6.4   3.5
 28000 -40.7 -41.3  255 115 59   6.8   3.7 | -41.6 -42.9  255 100 52   6.4   3.5
 27000 -38.2 -36.8  260 109 56   6.8   3.7 | -39.2 -38.6  255  94 49   6.4   3.5
 26000 -36.2 -33.2  260 104 53   6.5   3.6 | -37.2 -35.0  260  91 47   7.2   3.9
 25000 -34.2 -29.6  260  98 50   6.5   3.6 | -35.0 -31.0  260  90 46   7.2   4.0
 24000 -32.3 -26.1  260  92 47   6.6   3.6 | -32.8 -27.0  260  88 45   7.2   3.9
 23000 -30.1 -22.2  260  87 45   7.9   4.3 | -30.7 -23.3  260  87 45   6.9   3.8
 22000 -27.7 -17.9  260  83 43   7.9   4.4 | -28.7 -19.7  260  86 44   6.9   3.8
 21000 -25.3 -13.5  260  79 41   8.1   4.4 | -26.6 -15.9  265  86 44   6.9   3.8
 20000 -23.1  -9.6  260  73 38   7.2   3.9 | -24.6 -12.3  265  82 42   6.5   3.6
 19500 -22.0  -7.6  260  70 36   7.2   3.9 | -23.6 -10.5  265  79 41   6.5   3.6
 19000 -20.9  -5.6  260  67 34   7.2   3.9 | -22.7  -8.9  265  76 39   6.5   3.6
 18500 -19.9  -3.8  260  64 33   7.2   3.9 | -21.7  -7.1  265  73 37   6.6   3.6
 18000 -18.7  -1.7  260  60 31   7.6   4.2 | -20.8  -5.4  265  69 35   5.8   3.2
 17500 -17.6   0.3  255  55 28   7.6   4.2 | -19.9  -3.8  265  63 32   5.7   3.1
 17000 -16.5   2.3  255  50 26   6.9   3.8 | -19.1  -2.4  265  57 30   6.0   3.3
 16500 -15.6   3.9  260  49 25   5.4   3.0 | -18.1  -0.6  265  53 27   7.0   3.8
 16000 -14.8   5.4  260  50 26   5.4   2.9 | -17.1   1.2  265  50 26   6.8   3.7
 15500 -13.9   7.0  265  50 26   7.4   4.1 | -15.9   3.4  265  46 24   9.1   5.0
 15000 -12.8   9.0  265  49 25   7.2   4.0 | -14.6   5.7  265  43 22   8.9   4.9
 14500 -11.7  10.9  265  47 24   8.4   4.6 | -13.3   8.1  270  40 21   8.8   4.8
 14000 -10.4  13.3  260  44 22   8.6   4.7 | -12.0  10.4  270  37 19   8.8   4.8
 13500  -9.1  15.6  260  41 21   8.5   4.6 | -10.7  12.7  275  35 18   8.4   4.6
 13000  -7.9  17.8  260  40 21   8.4   4.6 |  -9.5  14.9  275  33 17   8.3   4.5
 12500  -6.6  20.1  260  39 20   8.4   4.6 |  -8.3  17.1  280  32 16   9.2   5.1
 12000  -5.4  22.3  265  40 21   7.9   4.3 |  -6.9  19.6  280  32 16   7.4   4.1
 11750  -4.9  23.2  265  41 21   7.7   4.2 |  -6.4  20.5  280  32 16   6.3   3.5
 11500  -4.3  24.3  265  41 21   8.2   4.5 |  -5.9  21.4  280  32 16   7.3   4.0
 11250  -3.6  25.5  265  41 21   9.0   4.9 |  -5.3  22.5  280  32 17   8.3   4.5
 11000  -3.0  26.6  265  42 21   8.0   4.4 |  -4.7  23.5  280  33 17   7.5   4.1
 10750  -2.5  27.5  265  42 22   6.6   3.6 |  -4.2  24.4  280  34 17   6.2   3.4
 10500  -2.0  28.4  270  42 22   6.6   3.6 |  -3.8  25.2  280  35 18   6.7   3.7
 10250  -1.0  30.2  265  42 21   6.9   3.8 |  -2.7  27.1  275  35 18   7.3   4.0
 10000  -0.6  30.9  265  41 21   6.2   3.4 |  -2.2  28.0  270  35 18   7.7   4.2
  9750  -0.1  31.8  265  40 21   6.8   3.7 |  -1.6  29.1  270  35 18   8.3   4.6
  9500   0.4  32.7  265  38 20   8.0   4.4 |  -1.0  30.2  265  34 17   8.5   4.7
  9250   1.0  33.8  260  36 18   7.4   4.1 |  -0.4  31.3  265  33 17   8.4   4.6
  9000   1.5  34.7  260  34 17   8.6   4.7 |   0.2  32.4  260  31 16   8.8   4.8
  8750   2.2  36.0  260  31 16   9.9   5.4 |   0.9  33.6  260  30 16   8.9   4.9
  8500   2.9  37.2  260  30 16   9.8   5.4 |   1.5  34.7  260  29 15   8.5   4.6
  8250   3.7  38.7  255  29 15   9.9   5.4 |   2.2  36.0  260  27 14   9.0   5.0
  8000   4.4  39.9  255  27 14   9.4   5.2 |   2.8  37.0  255  26 13   7.2   3.9
  7750   5.1  41.2  255  25 13  10.9   6.0 |   3.0  37.4  255  23 12  -1.5  -0.8
  7500   6.1  43.0  255  21 11  14.7   8.1 |   2.5  36.5  255  17  9 -10.2  -5.6
  7250   7.0  44.6  250  17  9   7.5   4.1 |   2.0  35.6  250  11  6   3.6   2.0
  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


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