Soaring Guidance
Issued by NWS Pueblo, CO

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6
000
UXUS97 KPUB 201159
SRGPUB

Soaring Forecast
National Weather Service Pueblo, Colorado
0459 MST Friday, January 20, 2017

This forecast is for Friday, January 20, 2017:

If the trigger temperature of 37.4 F/3.0 C is reached...then
   Thermal Soaring Index....................... Poor
   Maximum rate of lift........................ 0 ft/min (0.0 m/s)
   Maximum height of thermals.................. 11050 ft MSL (3880 ft AGL)

Forecast maximum temperature................... 37.0 F/3.2 C
Time of trigger temperature.................... 1330 MST
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................. 9230 ft MSL (2060 ft AGL)
Thermal soaring outlook for Saturday 01/21..... Poor

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

Remarks...

Sunrise/Sunset.................... 07:13:35 / 17:05:50 MST
Total possible sunshine........... 9 hr 52 min 15 sec (592 min 15 sec)
Altitude of sun at 12:10:05 MST... 31.16 degrees

Upper air data from numerical model forecast valid on 01/20/2017 at 0500 MST

Freezing level.................. Entire airmass below 32 F / 0 C
Convective condensation level... 11746 ft MSL (4576 ft AGL)
Lifted condensation level....... 11384 ft MSL (4214 ft AGL)
Lifted index.................... +7.2
K index......................... +13.7

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  -57.6 -71.7   240   20   10   3.8   2.1      M     M       M      M    M
 45000  -51.9 -61.4   215   31   16   3.8   2.1      M     M       M      M    M
 40000  -45.4 -49.7   220   26   14   4.1   2.3      M     M       M      M    M
 38000  -43.8 -46.8   215   25   13  -0.7  -0.4      M     M       M      M    M
 36000  -44.3 -47.7   195   27   14  -0.8  -0.4      M     M       M      M    M
 34000  -44.8 -48.6   180   33   17  -0.8  -0.4      M     M       M      M    M
 32000  -45.1 -49.2   160   35   18  -0.6  -0.3      M     M       M      M    M
 30000  -45.5 -49.9   140   40   21  -0.7  -0.4      M     M       M      M    M
 29000  -44.5 -48.1   140   40   21   6.5   3.6   23.4  74.1    15.9      M    M
 28000  -42.5 -44.5   145   37   19   6.6   3.6   22.1  71.8    15.1      M    M
 27000  -40.5 -40.9   155   35   18   6.7   3.6   21.0  69.7    14.4      M    M
 26000  -38.0 -36.4   165   31   16   6.8   3.7   19.6  67.3    13.5      M    M
 25000  -36.0 -32.8   170   27   14   6.8   3.7   18.4  65.1    12.7      M    M
 24000  -33.9 -29.0   175   23   12   6.8   3.7   17.4  63.3    12.0      M    M
 23000  -31.8 -25.2   185   20   10   7.6   4.2   16.4  61.6    11.3      M    M
 22000  -29.6 -21.3   185   17    9   7.5   4.1   15.6  60.0    10.7      M    M
 21000  -27.4 -17.3   190   14    7   7.5   4.1   14.8  58.7    10.2      M    M
 20000  -25.2 -13.4   195   12    6   7.2   4.0   14.0  57.2     9.6      M    M
 19500  -24.1 -11.4   195   12    6   7.2   4.0   13.5  56.3     9.2      M    M
 19000  -23.0  -9.4   190   11    6   7.2   4.0   13.1  55.6     8.9      M    M
 18500  -22.0  -7.6   190   10    5   7.2   4.0   12.7  54.8     8.5      M    M
 18000  -20.9  -5.6   190   10    5   7.0   3.8   12.3  54.1     8.2      M    M
 17500  -20.0  -4.0   185    8    4   5.8   3.2   11.7  53.0     7.7      M    M
 17000  -19.1  -2.4   180    6    3   5.8   3.2   11.0  51.9     7.2      M    M
 16500  -18.2  -0.8   170    4    2   6.4   3.5   10.4  50.8     6.7      M    M
 16000  -17.3   0.9   165    2    1   6.4   3.5    9.9  49.8     6.2      M    M
 15500  -16.3   2.7   140    1    0   6.1   3.4    9.3  48.8     5.7      M    M
 15000  -15.4   4.3   040    1    1   5.9   3.3    8.7  47.6     5.1      M    M
 14500  -14.6   5.7   025    3    2   6.0   3.3    8.1  46.5     4.6      M    M
 14000  -13.6   7.5   015    5    3   6.4   3.5    7.5  45.5     4.1      M    M
 13500  -12.7   9.1   010    7    3   6.3   3.5    7.0  44.5     3.6      M    M
 13000  -11.9  10.6   005    9    4   5.3   2.9    6.3  43.4     3.0      M    M
 12500  -11.1  12.0   360   11    5   5.6   3.1    5.6  42.1     2.3      M    M
 12000  -10.6  12.9   360   13    6   3.8   2.1    4.6  40.4     1.4      M    M
 11750  -10.1  13.8   355   13    7   6.5   3.5    4.3  39.8     1.1      M    M
 11500   -9.7  14.5   355   14    7   5.9   3.2    4.0  39.3     0.8      M    M
 11250   -9.3  15.3   355   15    8   5.1   2.8    3.7  38.7     0.5      M    M
 11000   -8.9  16.0   355   15    8   4.3   2.3    3.3  38.0     0.1      M    M
 10750   -8.6  16.5   355   15    8   4.7   2.6    2.9  37.2    -0.3    313  1.6
 10500   -8.2  17.2   355   16    8   4.8   2.6    2.5  36.5    -0.7    296  1.5
 10250   -7.9  17.8   360   16    8   4.5   2.4    2.1  35.8    -1.1    278  1.4
 10000   -7.3  18.9   005   15    8   4.2   2.3    1.3  34.3    -1.9    244  1.2
  9750   -7.0  19.4   010   15    8   4.2   2.3    0.8  33.5    -2.4    228  1.2
  9500   -6.7  19.9   015   15    8   4.8   2.6    0.4  32.8    -2.8    211  1.1
  9250   -6.3  20.7   010   15    8   5.4   3.0    0.1  32.1    -3.1    192  1.0
  9000   -5.9  21.4   010   16    8   4.4   2.4   -0.3  31.5    -3.5    174  0.9
  8750   -5.6  21.9   010   16    8   5.2   2.8   -0.7  30.7    -3.9    157  0.8
  8500   -5.1  22.8   005   16    8   7.6   4.2   -0.9  30.3    -4.2    135  0.7
  8250   -4.5  23.9   005   15    8   8.1   4.5   -1.1  30.1    -4.4    110  0.6
  8000   -4.0  24.8   360   15    7   7.6   4.2   -1.2  29.8    -4.5     85  0.4
  7750   -3.4  25.9   360   14    7   8.3   4.5   -1.4  29.6    -4.7     61  0.3
  7500   -2.7  27.1   350   11    6  10.3   5.7   -1.4  29.5    -4.8     34  0.2
  7250   -2.0  28.4   340    9    5   6.4   3.5   -1.4  29.4    -4.8      6  0.0
  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 * * * * * *

           01/20/2017 at 0800 MST          |       01/20/2017 at 1100 MST
                                           |
K index... +16.1  LI... +0.5               | K index... +17.5  LI... +0.4
CAPE... 0.0  CIN... -0.8                   | CAPE... 0.0  CIN... M
                                           |
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  235  19 10   4.1   2.2 | -55.7 -68.3  225  20 10   4.2   2.3
 45000 -50.3 -58.5  230  28 14   4.1   2.3 | -49.3 -56.7  225  22 11   4.3   2.4
 40000 -44.9 -48.8  215  20 11   3.4   1.9 | -44.2 -47.6  215  22 11   3.2   1.7
 38000 -43.4 -46.1  210  19 10   0.5   0.3 | -42.6 -44.7  215  22 11   1.1   0.6
 36000 -43.1 -45.6  205  21 11   0.4   0.2 | -42.0 -43.6  220  18 10   1.1   0.6
 34000 -42.9 -45.2  200  23 12   0.4   0.2 | -41.3 -42.3  235  16  8   1.0   0.5
 32000 -43.3 -45.9  170  25 13  -1.2  -0.6 | -42.1 -43.8  205  13  7  -2.2  -1.2
 30000 -44.0 -47.2  145  37 19  -1.0  -0.6 | -43.4 -46.1  160  17  9  -2.2  -1.2
 29000 -43.8 -46.8  140  39 20   3.7   2.0 | -43.7 -46.7  150  20 10   2.1   1.2
 28000 -42.7 -44.9  140  35 18   3.7   2.0 | -43.2 -45.8  145  19 10   1.8   1.0
 27000 -41.6 -42.9  140  32 16   3.7   2.0 | -42.6 -44.7  135  19 10   1.8   1.0
 26000 -40.5 -40.9  135  28 14   4.8   2.6 | -42.1 -43.8  130  18  9   2.9   1.6
 25000 -38.5 -37.3  140  20 11   6.6   3.6 | -39.5 -39.1  120  13  7   7.3   4.0
 24000 -36.1 -33.0  155  12  6   6.6   3.6 | -37.3 -35.1  110   9  4   7.4   4.0
 23000 -34.1 -29.4  185   7  3   7.6   4.2 | -35.2 -31.4  085   5  3   7.1   3.9
 22000 -31.7 -25.1  205   5  2   7.8   4.3 | -33.1 -27.6  045   6  3   7.0   3.9
 21000 -29.4 -20.9  235   4  2   7.8   4.3 | -31.0 -23.8  020   8  4   7.0   3.9
 20000 -27.3 -17.1  280   3  2   6.2   3.4 | -28.8 -19.8  010  12  6   7.7   4.2
 19500 -26.3 -15.3  310   4  2   6.3   3.5 | -27.7 -17.9  005  14  7   7.7   4.2
 19000 -25.4 -13.7  330   5  3   6.3   3.5 | -26.5 -15.7  360  16  8   7.7   4.2
 18500 -24.5 -12.1  340   7  4   6.3   3.5 | -25.4 -13.7  360  18  9   7.7   4.2
 18000 -23.5 -10.3  350   9  5   6.4   3.5 | -24.2 -11.6  355  20 10   7.7   4.2
 17500 -22.5  -8.5  350  11  6   8.0   4.4 | -23.1  -9.6  355  21 11   7.7   4.2
 17000 -21.3  -6.3  345  13  7   7.9   4.4 | -22.0  -7.6  355  21 11   7.7   4.2
 16500 -20.1  -4.2  345  14  7   7.3   4.0 | -20.8  -5.4  350  22 11   7.7   4.2
 16000 -19.1  -2.4  345  15  8   7.2   3.9 | -19.7  -3.5  350  22 11   7.7   4.2
 15500 -18.0  -0.4  350  16  8   7.4   4.0 | -18.5  -1.3  345  22 11   7.6   4.2
 15000 -16.9   1.6  345  18  9   7.7   4.2 | -17.5   0.5  340  22 11   7.2   3.9
 14500 -15.8   3.6  345  20 11   7.7   4.2 | -16.4   2.5  335  22 11   7.2   4.0
 14000 -14.6   5.7  345  21 11   7.8   4.3 | -15.3   4.5  335  22 11   7.7   4.2
 13500 -13.5   7.7  345  22 11   7.9   4.3 | -14.2   6.4  330  22 11   7.7   4.2
 13000 -12.4   9.7  345  22 11   7.4   4.0 | -13.1   8.4  330  21 11   7.3   4.0
 12500 -11.3  11.7  345  22 12   8.2   4.5 | -12.0  10.4  330  19 10   8.1   4.4
 12000 -10.6  12.9  345  22 11   4.1   2.3 | -11.2  11.8  325  16  8   4.7   2.6
 11750 -10.1  13.8  345  21 11   7.9   4.3 | -10.7  12.7  325  15  7   8.4   4.6
 11500  -9.5  14.9  345  20 10   7.4   4.1 | -10.1  13.8  330  13  7   7.9   4.3
 11250  -9.0  15.8  350  19 10   5.8   3.2 |  -9.5  14.9  330  12  6   6.4   3.5
 11000  -8.7  16.3  350  18  9   3.6   2.0 |  -9.2  15.4  325  11  5   4.8   2.6
 10750  -8.4  16.9  355  16  8   4.3   2.3 |  -8.8  16.2  320   9  5   6.4   3.5
 10500  -8.1  17.4  360  15  8   4.4   2.4 |  -8.3  17.1  315   8  4   7.1   3.9
 10250  -7.8  18.0  010  13  7   4.3   2.4 |  -7.8  18.0  310   6  3   6.5   3.5
 10000  -7.5  18.5  015  11  6   4.2   2.3 |  -7.3  18.9  305   5  3   5.9   3.2
  9750  -6.8  19.8  040   9  5   4.0   2.2 |  -6.4  20.5  275   3  2   6.3   3.4
  9500  -6.5  20.3  055   8  4   4.7   2.6 |  -6.0  21.2  245   3  1   6.1   3.3
  9250  -6.2  20.8  060   8  4   5.2   2.9 |  -5.5  22.1  245   3  1   5.9   3.2
  9000  -5.8  21.6  065   8  4   5.0   2.8 |  -5.1  22.8  240   3  1   6.2   3.4
  8750  -5.4  22.3  075   7  4   5.4   2.9 |  -4.6  23.7  235   3  1   7.2   4.0
  8500  -5.0  23.0  070   6  3   6.0   3.3 |  -4.1  24.6  235   3  2   7.5   4.1
  8250  -4.6  23.7  055   5  3   6.2   3.4 |  -3.6  25.5  245   3  2   7.3   4.0
  8000  -4.1  24.6  035   4  2   6.2   3.4 |  -3.0  26.6  255   4  2   7.2   3.9
  7750  -3.6  25.5  005   4  2   8.5   4.7 |  -2.5  27.5  255   4  2   9.9   5.5
  7500  -2.9  26.8  350   4  2  11.6   6.4 |  -1.6  29.1  255   3  1  15.0   8.2
  7250  -2.2  28.0  335   4  2   5.5   3.0 |  -0.7  30.7  255   2  1   5.4   3.0
  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

           01/20/2017 at 1400 MST          |       01/20/2017 at 1700 MST
                                           |
K index... +17.5  LI... -0.4               | K index... +14.2  LI... +0.3
CAPE... +52.7  CIN... -1.4                 | CAPE... +20.0  CIN... -19.7
                                           |
Height Temperature  Wnd WndSpd  Lapse Rate | Temperature  Wnd WndSpd  Lapse Rate
ft MSL deg C deg F  Dir kt m/s  C/km F/kft | deg C deg F  Dir kt m/s  C/km F/kft
--------------------------------------------------------------------------------
 50000 -55.3 -67.5  225  25 13   4.0   2.2 | -55.1 -67.2  230  24 13   3.5   1.9
 45000 -49.3 -56.7  215  22 11   4.0   2.2 | -49.5 -57.1  225  23 12   3.5   1.9
 40000 -45.1 -49.2  225  26 13   2.7   1.5 | -45.2 -49.4  235  24 13   2.8   1.6
 38000 -43.5 -46.3  230  27 14   1.2   0.7 | -43.6 -46.5  240  25 13   0.0   0.0
 36000 -42.7 -44.9  235  22 11   1.4   0.8 | -43.5 -46.3  240  21 11   0.2   0.1
 34000 -41.7 -43.1  240  17  9   1.3   0.7 | -43.4 -46.1  240  18  9   0.2   0.1
 32000 -42.5 -44.5  240  13  7  -2.4  -1.3 | -44.7 -48.5  255  14  7  -3.0  -1.6
 30000 -44.0 -47.2  225  10  5  -2.3  -1.3 | -46.5 -51.7  275  13  7  -2.8  -1.5
 29000 -44.2 -47.6  215   8  4   1.7   1.0 | -46.5 -51.7  280  12  6   4.1   2.2
 28000 -43.7 -46.7  180   5  3   1.6   0.9 | -45.3 -49.5  265  11  6   4.0   2.2
 27000 -43.2 -45.8  140   6  3   1.6   0.9 | -44.1 -47.4  250  10  5   4.0   2.2
 26000 -42.8 -45.0  115   9  5   4.0   2.2 | -42.9 -45.2  230  10  5   5.6   3.1
 25000 -40.6 -41.1  105   6  3   7.5   4.1 | -40.8 -41.4  240  11  6   7.1   3.9
 24000 -38.3 -36.9  075   2  1   7.5   4.1 | -38.7 -37.7  250  13  6   7.1   3.9
 23000 -36.1 -33.0  330   3  2   7.5   4.1 | -36.6 -33.9  255  14  7   7.5   4.1
 22000 -33.8 -28.8  330   6  3   7.6   4.2 | -34.1 -29.4  255  16  8   8.1   4.5
 21000 -31.5 -24.7  330  10  5   7.6   4.2 | -31.7 -25.1  250  19 10   8.1   4.5
 20000 -29.3 -20.7  330  13  7   7.9   4.3 | -29.2 -20.6  250  20 10   8.6   4.7
 19500 -28.1 -18.6  330  14  7   7.9   4.3 | -28.0 -18.4  250  20 10   8.6   4.7
 19000 -26.9 -16.4  335  15  8   7.9   4.3 | -26.7 -16.1  255  20 10   8.6   4.7
 18500 -25.7 -14.3  335  16  8   7.9   4.4 | -25.4 -13.7  255  19 10   8.6   4.7
 18000 -24.5 -12.1  335  18  9   8.0   4.4 | -24.1 -11.4  255  19 10   8.8   4.8
 17500 -23.4 -10.1  335  19 10   7.7   4.2 | -22.9  -9.2  260  18  9   7.1   3.9
 17000 -22.2  -8.0  335  21 11   7.7   4.2 | -21.9  -7.4  270  17  9   7.0   3.9
 16500 -21.1  -6.0  335  23 12   7.5   4.1 | -20.8  -5.4  285  16  8   6.5   3.6
 16000 -19.5  -3.1  330  26 14   7.1   3.9 | -19.9  -3.8  295  16  8   6.0   3.3
 15500 -18.4  -1.1  330  28 15   7.3   4.0 | -18.6  -1.5  310  19 10   6.9   3.8
 15000 -17.3   0.9  330  30 16   7.4   4.0 | -17.5   0.5  315  20 11   7.2   4.0
 14500 -16.3   2.7  330  32 16   7.5   4.1 | -16.4   2.5  320  23 12   7.5   4.1
 14000 -15.1   4.8  325  32 17   7.8   4.3 | -15.3   4.5  320  23 12   7.8   4.3
 13500 -13.9   7.0  320  33 17   7.7   4.2 | -14.1   6.6  320  24 12   7.9   4.3
 13000 -12.8   9.0  320  32 16   7.4   4.0 | -12.9   8.8  315  24 12   7.8   4.3
 12500 -11.7  10.9  315  30 16   5.5   3.0 | -11.8  10.8  310  23 12   6.4   3.5
 12000 -10.8  12.6  315  28 15   8.9   4.9 | -10.6  12.9  310  22 11  10.4   5.7
 11750 -10.2  13.6  315  27 14   8.2   4.5 |  -9.9  14.2  310  22 11   9.8   5.4
 11500  -9.5  14.9  310  26 13   8.2   4.5 |  -9.1  15.6  310  21 11   9.5   5.2
 11250  -9.0  15.8  310  25 13   6.5   3.6 |  -8.5  16.7  310  20 10   8.2   4.5
 11000  -8.5  16.7  310  24 12   6.7   3.7 |  -7.9  17.8  310  19 10   9.0   4.9
 10750  -8.0  17.6  310  22 11   7.7   4.2 |  -7.2  19.0  315  19 10  10.0   5.5
 10500  -7.4  18.7  310  21 11   7.4   4.1 |  -6.4  20.5  315  18  9   9.5   5.2
 10250  -6.9  19.6  310  20 10   7.4   4.1 |  -5.8  21.6  315  17  9   9.0   4.9
 10000  -6.4  20.5  310  19 10   7.3   4.0 |  -5.1  22.8  315  16  8   9.0   4.9
  9750  -5.8  21.6  310  17  9   7.3   4.0 |  -4.4  24.1  315  15  8   9.6   5.3
  9500  -5.3  22.5  310  16  8   7.4   4.0 |  -3.7  25.3  315  14  7   9.1   5.0
  9250  -4.7  23.5  305  14  7   7.6   4.2 |  -3.1  26.4  315  13  7   8.4   4.6
  9000  -4.2  24.4  305  13  7   7.4   4.1 |  -2.5  27.5  315  12  6   8.1   4.5
  8750  -3.6  25.5  300  11  6   9.2   5.0 |  -1.8  28.8  315  10  5   9.6   5.3
  8500  -2.9  26.8  300  10  5   9.2   5.1 |  -1.1  30.0  315   9  5   7.8   4.3
  8250  -2.3  27.9  295   8  4   8.0   4.4 |  -0.7  30.7  310   8  4   5.3   2.9
  8000  -1.7  28.9  290   7  4   7.7   4.2 |  -0.3  31.5  305   6  3   5.9   3.3
  7750  -1.2  29.8  285   6  3  10.2   5.6 |   0.1  32.2  300   5  3   6.0   3.3
  7500  -0.4  31.3  280   5  3   8.8   4.8 |   0.4  32.7  295   3  2   1.6   0.9
  7250   0.0  32.0  275   5  2   4.2   2.3 |   0.3  32.5  290   2  1  -2.7  -1.5
  7000   0.4  32.7  270   4  2   7.9   4.3 |   0.1  32.2  275   2  1   0.6   0.3
  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.