Soaring Guidance
Issued by NWS Pueblo, CO

Home | Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13

825
UXUS97 KPUB 231250
SRGPUB

Soaring Forecast
National Weather Service Pueblo, Colorado
0550 MST Friday, February 23, 2018

This forecast is for Friday, February 23, 2018:

If the trigger temperature of 30.3 F/-0.9 C is reached...then
   Thermal Soaring Index....................... Good
   Maximum rate of lift........................ 614 ft/min (3.1 m/s)
   Maximum height of thermals.................. 14330 ft MSL (6714 ft AGL)

Forecast maximum temperature................... 34.0 F/1.6 C
Time of trigger temperature.................... 1145 MST
Time of overdevelopment........................ 1500 MST
Middle/high clouds during soaring window....... None
Surface winds during soaring window............ 20 mph or less
Height of the -3 thermal index................. 9470 ft MSL (1854 ft AGL)
Thermal soaring outlook for Saturday 02/24..... Fair

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

Remarks...

Sunrise/Sunset.................... 06:39:48 / 17:45:23 MST
Total possible sunshine........... 11 hr 5 min 35 sec (665 min 35 sec)
Altitude of sun at 12:12:35 MST... 41.30 degrees

Upper air data from numerical model forecast valid on 02/23/2018 at 0500 MST

Freezing level.................. Entire airmass below 32 F / 0 C
Convective condensation level... 17211 ft MSL (9595 ft AGL)
Lifted condensation level....... 14745 ft MSL (7129 ft AGL)
Lifted index.................... +9.6
K index......................... -17.8

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  -59.9 -75.8   230   52   27   2.0   1.1      M     M       M      M    M
 45000  -56.9 -70.4   225   57   29   2.0   1.1      M     M       M      M    M
 40000  -55.4 -67.7   225   51   26   0.8   0.4      M     M       M      M    M
 38000  -54.9 -66.8   230   49   25   1.0   0.5      M     M       M      M    M
 36000  -54.3 -65.7   225   53   27   1.0   0.5      M     M       M      M    M
 34000  -53.8 -64.8   225   57   29   0.5   0.3      M     M       M      M    M
 32000  -51.1 -60.0   225   56   29   5.1   2.8      M     M       M      M    M
 30000  -48.0 -54.4   225   54   28   4.9   2.7      M     M       M      M    M
 29000  -46.1 -51.0   225   53   27   6.7   3.7   20.3  68.6    14.9      M    M
 28000  -44.1 -47.4   225   52   27   6.7   3.7   19.1  66.4    14.1      M    M
 27000  -42.1 -43.8   225   52   27   6.7   3.7   18.0  64.4    13.4      M    M
 26000  -40.1 -40.2   230   51   26   6.6   3.6   16.9  62.4    12.7      M    M
 25000  -38.1 -36.6   230   50   26   6.6   3.6   15.6  60.1    11.8      M    M
 24000  -36.2 -33.2   230   49   25   6.6   3.6   14.5  58.1    11.0      M    M
 23000  -34.3 -29.7   230   47   24   5.9   3.2   13.4  56.1    10.2      M    M
 22000  -32.0 -25.6   230   44   23   6.0   3.3   11.6  52.9     8.9      M    M
 21000  -30.2 -22.4   230   41   21   5.6   3.1   10.3  50.6     7.9      M    M
 20000  -27.8 -18.0   230   39   20   9.0   4.9    9.8  49.6     7.5      M    M
 19500  -26.4 -15.5   230   38   20   8.9   4.9    9.6  49.3     7.4      M    M
 19000  -25.1 -13.2   230   38   19   9.0   4.9    9.5  49.1     7.3      M    M
 18500  -23.8 -10.8   230   37   19   9.2   5.1    9.4  48.9     7.3      M    M
 18000  -22.6  -8.7   230   36   19   5.9   3.2    9.1  48.3     7.0      M    M
 17500  -21.7  -7.1   230   36   19   5.8   3.2    8.4  47.1     6.5      M    M
 17000  -20.8  -5.4   235   36   19   4.0   2.2    7.8  46.0     6.0      M    M
 16500  -20.6  -5.1   235   34   18   2.1   1.1    6.5  43.6     4.8      M    M
 16000  -20.3  -4.5   235   32   17   1.9   1.1    5.2  41.3     3.6      M    M
 15500  -20.0  -4.0   235   30   15   1.5   0.8    3.8  38.9     2.4      M    M
 15000  -19.8  -3.6   235   27   14   1.1   0.6    2.5  36.5     1.2      M    M
 14500  -19.3  -2.7   235   24   12   5.8   3.2    1.5  34.7     0.2      M    M
 14000  -18.5  -1.3   235   20   10   5.1   2.8    0.8  33.4    -0.4    590  3.0
 13500  -17.6   0.3   235   17    9   7.5   4.1    0.2  32.3    -1.0    548  2.8
 13000  -16.5   2.3   235   16    8   6.9   3.8   -0.2  31.7    -1.3    499  2.5
 12500  -15.1   4.8   240   15    8   9.9   5.4   -0.2  31.6    -1.4    443  2.3
 12000  -14.0   6.8   240   16    8   7.6   4.2   -0.6  31.0    -1.8    394  2.0
 11750  -13.4   7.9   240   16    8   8.3   4.6   -0.7  30.7    -1.9    369  1.9
 11500  -12.7   9.1   240   15    8   9.7   5.3   -0.8  30.6    -2.0    341  1.7
 11250  -12.0  10.4   240   14    7   9.3   5.1   -0.8  30.6    -2.0    313  1.6
 11000  -11.3  11.7   240   14    7   9.1   5.0   -0.8  30.5    -2.1    285  1.4
 10750  -10.7  12.7   240   13    7   8.7   4.8   -0.9  30.4    -2.1    258  1.3
 10500  -10.0  14.0   240   13    7   7.8   4.3   -1.0  30.2    -2.3    232  1.2
 10250   -9.5  14.9   240   13    7   8.7   4.8   -1.1  29.9    -2.4    207  1.1
 10000   -8.8  16.2   245   13    7  10.1   5.5   -1.2  29.9    -2.4    178  0.9
  9750   -8.1  17.4   245   13    7   7.3   4.0   -1.2  29.8    -2.5    150  0.8
  9500   -7.7  18.1   245   12    6   4.7   2.6   -1.5  29.2    -2.8    131  0.7
  9250   -7.3  18.9   240   12    6   5.8   3.2   -1.9  28.6    -3.2    112  0.6
  9000   -6.9  19.6   240   11    6   4.2   2.3   -2.2  28.0    -3.5     93  0.5
  8750   -6.7  19.9   240   10    5   0.5   0.3   -2.8  27.0    -4.1     81  0.4
  8500   -6.8  19.8   235    9    5  -2.3  -1.2   -3.6  25.5    -4.9     76  0.4
  8250   -6.9  19.6   230    8    4   2.8   1.5   -4.4  24.1    -5.8     71  0.4
  8000   -6.7  19.9   230    7    4  -3.6  -2.0   -4.9  23.1    -6.3     57  0.3
  7750   -7.9  17.8   225    4    2 -28.1 -15.4   -6.9  19.6    -8.3     86  0.4
  7500      M     M     M    M    M     M     M      M     M       M      M    M
  7250      M     M     M    M    M     M     M      M     M       M      M    M
  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 * * * * * *

           02/23/2018 at 0800 MST          |       02/23/2018 at 1100 MST
                                           |
CAPE...     0.0    LI...       +6.0        | CAPE...    +0.8    LI...       +5.1
CINH...     0.0    K Index... -14.3        | CINH...     0.0    K Index...  -9.0
                                           |
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 -59.1 -74.4  235  50 26   2.0   1.1 | -58.6 -73.5  230  49 25   2.0   1.1
 45000 -56.1 -69.0  225  57 29   2.0   1.1 | -55.6 -68.1  230  54 28   2.0   1.1
 40000 -56.1 -69.0  225  53 27  -0.3  -0.2 | -57.2 -71.0  230  52 27  -1.5  -0.8
 38000 -56.2 -69.2  225  51 26   0.7   0.4 | -57.6 -71.7  230  51 26   2.5   1.4
 36000 -55.8 -68.4  225  53 27   0.7   0.4 | -56.2 -69.2  225  52 27   2.4   1.3
 34000 -55.4 -67.7  225  55 28   0.0   0.0 | -54.7 -66.5  220  54 28   1.9   1.1
 32000 -51.7 -61.1  225  55 28   7.1   3.9 | -51.0 -59.8  220  54 28   6.7   3.7
 30000 -47.4 -53.3  225  54 28   7.1   3.9 | -47.0 -52.6  220  53 28   6.8   3.7
 29000 -45.3 -49.5  225  54 28   6.8   3.7 | -45.1 -49.2  225  53 27   6.4   3.5
 28000 -43.3 -45.9  225  53 27   6.8   3.7 | -43.1 -45.6  225  52 27   6.4   3.5
 27000 -41.3 -42.3  225  52 27   6.8   3.7 | -41.2 -42.2  225  52 27   6.4   3.5
 26000 -39.3 -38.7  225  51 26   6.4   3.5 | -39.3 -38.7  225  51 26   6.8   3.8
 25000 -37.3 -35.1  225  50 26   6.5   3.5 | -37.2 -35.0  225  50 26   6.8   3.7
 24000 -35.4 -31.7  225  48 25   6.5   3.6 | -34.7 -30.5  225  48 25   6.8   3.7
 23000 -33.1 -27.6  225  46 24   5.5   3.0 | -32.8 -27.0  225  47 24   5.9   3.2
 22000 -31.5 -24.7  225  44 23   5.5   3.0 | -31.0 -23.8  225  45 23   5.8   3.2
 21000 -29.8 -21.6  230  42 22   5.2   2.9 | -29.3 -20.7  225  43 22   5.9   3.2
 20000 -27.7 -17.9  230  40 21   7.6   4.1 | -27.5 -17.5  225  42 21   5.8   3.2
 19500 -26.6 -15.9  230  39 20   7.5   4.1 | -26.7 -16.1  225  41 21   5.8   3.2
 19000 -25.5 -13.9  230  38 20   7.6   4.1 | -25.8 -14.4  230  40 21   5.8   3.2
 18500 -24.4 -11.9  230  37 19   7.6   4.2 | -25.0 -13.0  230  40 20   5.6   3.1
 18000 -23.2  -9.8  230  37 19   7.1   3.9 | -24.0 -11.2  230  39 20   7.9   4.3
 17500 -22.2  -8.0  230  36 19   7.0   3.9 | -22.8  -9.0  230  38 19   7.9   4.3
 17000 -21.1  -6.0  230  36 19   5.9   3.2 | -21.6  -6.9  230  37 19   7.1   3.9
 16500 -20.4  -4.7  230  35 18   4.7   2.6 | -20.7  -5.3  230  35 18   6.0   3.3
 16000 -19.7  -3.5  230  34 17   4.6   2.5 | -19.8  -3.6  230  34 17   5.8   3.2
 15500 -19.1  -2.4  230  32 16   3.9   2.2 | -19.1  -2.4  230  32 16   3.9   2.1
 15000 -18.5  -1.3  235  29 15   4.2   2.3 | -18.5  -1.3  230  29 15   4.0   2.2
 14500 -18.1  -0.6  235  27 14   1.9   1.1 | -17.9  -0.2  230  26 14   3.8   2.1
 14000 -17.8  -0.0  235  23 12   1.9   1.0 | -17.4   0.7  230  23 12   3.7   2.1
 13500 -17.2   1.0  235  20 10   5.9   3.2 | -16.7   1.9  230  19 10   4.7   2.6
 13000 -16.4   2.5  235  17  9   5.2   2.9 | -16.0   3.2  235  15  8   4.2   2.3
 12500 -15.1   4.8  235  16  8   9.6   5.3 | -15.0   5.0  230  13  6   8.2   4.5
 12000 -14.1   6.6  235  14  7   6.8   3.7 | -14.1   6.6  230  10  5   6.5   3.6
 11750 -13.6   7.5  235  13  7   7.5   4.1 | -13.6   7.5  225   9  4   6.3   3.4
 11500 -12.9   8.8  235  12  6   8.8   4.9 | -13.2   8.2  225   8  4   6.5   3.5
 11250 -12.3   9.9  235  11  6   8.9   4.9 | -12.7   9.1  225   8  4   8.0   4.4
 11000 -11.6  11.1  240  11  6   9.3   5.1 | -12.0  10.4  220   8  4   9.5   5.2
 10750 -10.9  12.4  240  10  5   8.2   4.5 | -11.3  11.7  220   7  4   7.9   4.3
 10500 -10.4  13.3  235  10  5   6.5   3.6 | -10.8  12.6  220   7  4   5.7   3.1
 10250  -9.9  14.2  235   9  5   7.8   4.3 | -10.4  13.3  215   7  3   7.6   4.2
 10000  -9.2  15.4  235   9  4   9.6   5.3 |  -9.7  14.5  215   6  3  11.0   6.0
  9750  -8.6  16.5  235   8  4   7.2   3.9 |  -8.9  16.0  210   6  3   8.1   4.4
  9500  -8.2  17.2  230   8  4   4.9   2.7 |  -8.5  16.7  205   6  3   5.1   2.8
  9250  -7.8  18.0  230   7  4   5.9   3.3 |  -8.0  17.6  200   6  3   6.6   3.6
  9000  -7.3  18.9  225   7  3   4.7   2.6 |  -7.5  18.5  195   6  3   9.7   5.3
  8750  -7.1  19.2  220   6  3   2.1   1.2 |  -6.7  19.9  190   6  3  10.4   5.7
  8500  -7.1  19.2  220   6  3  -0.7  -0.4 |  -6.0  21.2  185   6  3   9.6   5.3
  8250  -7.0  19.4  215   6  3   5.8   3.2 |  -5.3  22.5  180   6  3   8.3   4.6
  8000  -6.4  20.5  215   5  3   4.3   2.3 |  -4.6  23.7  175   6  3  12.4   6.8
  7750  -6.9  19.6  210   4  2 -16.2  -8.9 |  -3.2  26.2  170   5  3  24.8  13.6
  7500     M     M    M   M  M     M     M |     M     M    M   M  M     M     M
  7250     M     M    M   M  M     M     M |     M     M    M   M  M     M     M
  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

           02/23/2018 at 1400 MST          |       02/23/2018 at 1700 MST
                                           |
CAPE...    +3.7    LI...       +4.2        | CAPE...    +1.4    LI...       +2.1
CINH...    -1.6    K Index...  -8.6        | CINH...    -2.0    K Index... -14.3
                                           |
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 -59.8 -75.6  230  48 25   2.7   1.5 | -59.0 -74.2  230  43 22   3.8   2.1
 45000 -55.7 -68.3  225  49 25   2.7   1.5 | -53.3 -63.9  225  44 23   3.8   2.1
 40000 -56.0 -68.8  225  47 24  -0.6  -0.4 | -54.2 -65.6  230  46 24  -1.4  -0.7
 38000 -56.1 -69.0  225  47 24   2.1   1.1 | -54.8 -66.6  230  48 24   1.2   0.7
 36000 -54.8 -66.6  225  50 26   2.0   1.1 | -54.2 -65.6  225  51 26   1.0   0.5
 34000 -53.6 -64.5  225  53 27   1.7   0.9 | -53.6 -64.5  225  55 28   0.9   0.5
 32000 -50.3 -58.5  220  53 27   6.2   3.4 | -50.8 -59.4  225  55 29   5.8   3.2
 30000 -46.6 -51.9  220  53 27   6.1   3.4 | -47.3 -53.1  225  55 28   5.8   3.2
 29000 -44.6 -48.3  220  53 27   6.5   3.6 | -45.4 -49.7  225  55 28   6.5   3.6
 28000 -42.7 -44.9  220  52 27   6.5   3.6 | -43.5 -46.3  225  55 28   6.5   3.6
 27000 -40.7 -41.3  225  52 27   6.5   3.6 | -41.5 -42.7  225  55 28   6.5   3.6
 26000 -38.8 -37.8  225  51 26   6.3   3.4 | -39.6 -39.3  225  54 28   5.6   3.1
 25000 -36.9 -34.4  225  51 26   6.3   3.5 | -37.5 -35.5  225  52 27   5.5   3.0
 24000 -34.5 -30.1  225  50 26   6.3   3.4 | -35.9 -32.6  225  51 26   5.5   3.0
 23000 -32.8 -27.0  225  48 25   5.4   2.9 | -34.3 -29.7  225  49 25   4.6   2.5
 22000 -31.1 -24.0  225  46 24   5.4   2.9 | -32.9 -27.2  225  46 23   4.7   2.6
 21000 -29.5 -21.1  225  44 23   5.3   2.9 | -31.5 -24.7  225  43 22   4.6   2.5
 20000 -27.8 -18.0  225  42 22   6.0   3.3 | -29.7 -21.5  230  40 21   7.1   3.9
 19500 -26.9 -16.4  225  41 21   6.0   3.3 | -28.6 -19.5  230  39 20   7.1   3.9
 19000 -26.0 -14.8  230  40 21   6.0   3.3 | -27.6 -17.7  230  38 19   7.1   3.9
 18500 -25.1 -13.2  230  39 20   6.0   3.3 | -26.5 -15.7  230  36 19   7.2   3.9
 18000 -24.2 -11.6  230  38 20   6.2   3.4 | -25.4 -13.7  230  35 18   6.2   3.4
 17500 -23.2  -9.8  230  38 19   6.3   3.5 | -24.6 -12.3  230  34 17   5.8   3.2
 17000 -22.3  -8.1  230  37 19   6.4   3.5 | -23.7 -10.7  230  32 16   5.6   3.1
 16500 -21.3  -6.3  230  36 18   6.5   3.6 | -22.9  -9.2  230  30 15   5.1   2.8
 16000 -20.3  -4.5  235  34 17   6.6   3.6 | -22.2  -8.0  225  27 14   5.1   2.8
 15500 -19.6  -3.3  235  32 16   4.0   2.2 | -21.4  -6.5  225  25 13   6.3   3.5
 15000 -19.0  -2.2  235  29 15   4.2   2.3 | -20.5  -4.9  220  23 12   6.1   3.3
 14500 -18.3  -0.9  235  26 13   4.5   2.5 | -19.4  -2.9  220  21 11   9.0   4.9
 14000 -17.7   0.1  235  22 12   4.4   2.4 | -18.1  -0.6  215  20 10   9.2   5.0
 13500 -16.9   1.6  235  19 10   7.0   3.8 | -16.7   1.9  215  18  9   9.3   5.1
 13000 -15.8   3.6  230  17  9   6.8   3.8 | -15.3   4.5  215  17  9   8.2   4.5
 12500 -14.5   5.9  230  15  8   9.6   5.3 | -13.4   7.9  215  17  9  12.2   6.7
 12000 -13.4   7.9  225  13  7   7.4   4.1 | -12.4   9.7  210  16  8   7.2   4.0
 11750 -12.9   8.8  225  12  6   7.2   3.9 | -11.9  10.6  210  15  8   7.0   3.8
 11500 -12.3   9.9  225  12  6   7.3   4.0 | -11.3  11.7  210  15  8   7.9   4.3
 11250 -11.8  10.8  220  11  6   7.6   4.1 | -10.7  12.7  210  14  7   7.2   4.0
 11000 -11.2  11.8  220  11  6   7.8   4.3 | -10.3  13.5  210  13  7   6.6   3.6
 10750 -10.6  12.9  215  11  5   7.2   4.0 |  -9.8  14.4  205  12  6   6.5   3.5
 10500 -10.2  13.6  210  10  5   5.4   3.0 |  -9.3  15.3  205  12  6   5.2   2.8
 10250  -9.7  14.5  205  10  5   7.1   3.9 |  -9.0  15.8  200  11  6   5.4   3.0
 10000  -9.1  15.6  205  10  5  10.2   5.6 |  -8.5  16.7  200  11  5   7.0   3.9
  9750  -8.3  17.1  200  10  5   9.2   5.0 |  -8.0  17.6  195  10  5   5.4   3.0
  9500  -7.7  18.1  195   9  5   8.0   4.4 |  -7.7  18.1  195  10  5   2.9   1.6
  9250  -7.1  19.2  185   9  5   8.5   4.7 |  -7.5  18.5  190   9  5   3.4   1.9
  9000  -6.4  20.5  180   9  5  10.2   5.6 |  -7.2  19.0  185   8  4   6.6   3.6
  8750  -5.6  21.9  180   9  5  10.6   5.8 |  -6.6  20.1  175   8  4   8.9   4.9
  8500  -4.8  23.4  180   9  5  10.4   5.7 |  -5.9  21.4  175   8  4   9.1   5.0
  8250  -4.1  24.6  175   9  5   9.4   5.1 |  -4.6  23.7  170   8  4   8.5   4.7
  8000  -3.3  26.1  175   9  5  11.8   6.5 |  -3.9  25.0  165   6  3   9.4   5.1
  7750  -2.1  28.2  175   8  4  21.4  11.7 |  -3.1  26.4  160   5  2  14.8   8.1
  7500     M     M    M   M  M     M     M |     M     M    M   M  M     M     M
  7250     M     M    M   M  M     M     M |     M     M    M   M  M     M     M
  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).  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.