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
000
UXUS97 KPUB 201221
SRGPUB

Soaring Forecast
National Weather Service Pueblo, Colorado
0521 MST Friday, February 20, 2015

This forecast is for Friday, February 20, 2015:

If the trigger temperature of 51.3 F/10.7 C is reached...then
   Thermal Soaring Index....................... Fair
   Maximum rate of lift........................ 309 ft/min (1.6 m/s)
   Maximum height of thermals.................. 10910 ft MSL (3741 ft AGL)

Forecast maximum temperature................... 51.0 F/11.0 C
Time of trigger temperature.................... 1415 MST
Time of overdevelopment........................ None
Middle/high clouds during soaring window....... None
Surface winds during soaring window............ 20 mph or less
Height of the -3 thermal index................. 7999 ft MSL (830 ft AGL)
Thermal soaring outlook for Saturday 02/21..... Poor

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

Remarks...

Sunrise/Sunset.................... 06:44:01 / 17:40:38 MST
Total possible sunshine........... 10 hr 56 min 38 sec (656 min 38 sec)
Altitude of sun at 12:12:36 MST... 40.25 degrees

Upper air data from numerical model forecast valid on 02/20/2015 at 0500 MST

Freezing level.................. 7260 ft MSL (91 ft AGL)
Additional freezing level....... 10613 ft MSL (3444 ft AGL)
Convective condensation level... 17626 ft MSL (10457 ft AGL)
Lifted condensation level....... 16157 ft MSL (8987 ft AGL)
Lifted index.................... +4.4
K index......................... -5.3

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  -59.5 -75.1   285   51   26   2.0   1.1      M     M       M      M    M
 45000  -56.6 -69.9   285   79   40   1.9   1.0      M     M       M      M    M
 40000  -59.5 -75.1   285   97   50  -2.2  -1.2      M     M       M      M    M
 38000  -59.5 -75.1   285   96   50   3.9   2.1      M     M       M      M    M
 36000  -57.2 -71.0   285   83   43   3.8   2.1      M     M       M      M    M
 34000  -54.8 -66.6   280   70   36   6.3   3.5      M     M       M      M    M
 32000  -50.4 -58.7   280   67   34   7.3   4.0      M     M       M      M    M
 30000  -45.9 -50.6   280   63   32   8.0   4.4   24.2  75.5    10.4      M    M
 29000  -43.5 -46.3   280   61   31   8.0   4.4   23.4  74.0     9.9      M    M
 28000  -41.2 -42.2   280   59   30   8.0   4.4   22.7  72.8     9.5      M    M
 27000  -38.2 -36.8   285   57   29   7.9   4.4   22.0  71.6     9.1      M    M
 26000  -35.8 -32.4   285   55   28   7.8   4.3   21.2  70.1     8.5      M    M
 25000  -33.5 -28.3   285   53   27   7.8   4.3   20.4  68.8     8.0      M    M
 24000  -31.1 -24.0   285   51   26   7.8   4.3   19.8  67.7     7.6      M    M
 23000  -29.0 -20.2   285   48   25   6.9   3.8   18.8  65.8     6.8      M    M
 22000  -26.9 -16.4   285   44   23   6.9   3.8   17.8  64.0     6.1      M    M
 21000  -24.9 -12.8   285   40   21   7.4   4.1   16.9  62.4     5.3      M    M
 20000  -22.5  -8.5   290   36   19   8.0   4.4   16.2  61.1     4.8      M    M
 19500  -21.2  -6.2   290   34   18   8.0   4.4   15.9  60.6     4.6      M    M
 19000  -20.0  -4.0   290   33   17   8.0   4.4   15.6  60.1     4.4      M    M
 18500  -18.8  -1.8   290   31   16   7.9   4.3   15.4  59.7     4.2      M    M
 18000  -17.7   0.1   290   27   14   7.3   4.0   15.0  59.0     3.9      M    M
 17500  -16.6   2.1   290   24   12   7.3   4.0   14.6  58.2     3.5      M    M
 17000  -15.5   4.1   285   20   10   7.3   4.0   14.2  57.5     3.2      M    M
 16500  -14.4   6.1   280   17    9   7.4   4.0   13.8  56.8     2.8      M    M
 16000  -13.3   8.1   275   13    7   8.4   4.6   13.4  56.1     2.5      M    M
 15500  -11.9  10.6   270   12    6   9.1   5.0   13.3  55.9     2.4      M    M
 15000  -10.5  13.1   265   11    6   8.7   4.7   13.2  55.8     2.3      M    M
 14500   -9.5  14.9   270   10    5   6.6   3.6   12.8  55.0     2.0      M    M
 14000   -8.5  16.7   285    9    4   6.7   3.7   12.3  54.2     1.5      M    M
 13500   -7.4  18.7   300    9    5   7.7   4.2   11.9  53.4     1.1      M    M
 13000   -6.3  20.7   315   11    5   7.4   4.1   11.6  52.8     0.8      M    M
 12500   -5.0  23.0   325   13    7   9.8   5.4   11.4  52.5     0.6      M    M
 12000   -3.6  25.5   330   16    8   8.6   4.7   11.3  52.4     0.5      M    M
 11750   -3.0  26.6   330   17    9   8.4   4.6   11.2  52.2     0.4      M    M
 11500   -2.4  27.7   330   19   10   8.5   4.7   11.1  52.0     0.3      M    M
 11250   -1.7  28.9   330   21   11   8.6   4.7   11.0  51.8     0.2      M    M
 11000   -1.1  30.0   330   23   12   8.2   4.5   10.9  51.7     0.1      M    M
 10750   -0.5  31.1   330   24   13   7.2   4.0   10.8  51.4    -0.0    305  1.5
 10500   -0.0  32.0   325   26   13   6.9   3.8   10.5  51.0    -0.3    282  1.4
 10250    0.5  32.9   325   27   14   7.0   3.9   10.3  50.6    -0.5    259  1.3
 10000    1.5  34.7   325   29   15   6.9   3.8    9.9  49.8    -1.0    214  1.1
  9750    2.0  35.6   325   28   15   7.3   4.0    9.7  49.4    -1.2    192  1.0
  9500    2.5  36.5   325   27   14   7.5   4.1    9.5  49.1    -1.4    168  0.9
  9250    3.1  37.6   325   26   14   7.5   4.1    9.3  48.8    -1.6    145  0.7
  9000    3.6  38.5   325   25   13   7.2   4.0    9.2  48.5    -1.8    121  0.6
  8750    4.1  39.4   325   24   13   6.4   3.5    8.9  48.1    -2.0     99  0.5
  8500    4.6  40.3   325   23   12   7.2   3.9    8.7  47.6    -2.3     77  0.4
  8250    5.1  41.2   325   22   11   3.8   2.1    8.4  47.2    -2.5     55  0.3
  8000    5.1  41.2   325   21   11  -3.1  -1.7    7.7  45.8    -3.3     48  0.2
  7750    4.3  39.7   325   20   10 -20.9 -11.5    6.2  43.2    -4.8     63  0.3
  7500    1.7  35.1   315   14    7 -45.6 -25.0    2.9  37.2    -8.2    135  0.7
  7250   -1.0  30.2   305    9    4  -2.2  -1.2   -0.4  31.3   -11.5    207  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 * * * * * *

           02/20/2015 at 0800 MST          |       02/20/2015 at 1100 MST
                                           |
K index... -4.3  LI... +1.7                | K index... +5.3  LI... +0.8
CAPE... 0.0  CIN... -0.7                   | 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 -58.8 -73.8  285  47 24   1.1   0.6 | -57.0 -70.6  280  46 24   0.6   0.3
 45000 -57.2 -71.0  280  70 36   1.0   0.6 | -56.1 -69.0  280  75 39   0.5   0.3
 40000 -58.1 -72.6  285  93 48  -0.8  -0.4 | -58.6 -73.5  280  88 45  -1.9  -1.0
 38000 -58.0 -72.4  280  98 50   2.3   1.3 | -58.9 -74.0  280  91 47   3.0   1.6
 36000 -56.6 -69.9  280  95 49   2.3   1.3 | -57.0 -70.6  280  94 48   3.0   1.7
 34000 -55.2 -67.4  275  93 48   4.8   2.6 | -55.2 -67.4  275  96 50   4.0   2.2
 32000 -51.1 -60.0  275  82 42   6.8   3.8 | -51.6 -60.9  275  87 45   6.1   3.4
 30000 -46.9 -52.4  275  72 37   7.5   4.1 | -47.9 -54.2  270  77 40   7.0   3.8
 29000 -44.7 -48.5  275  70 36   7.6   4.1 | -45.6 -50.1  270  72 37   7.8   4.3
 28000 -42.4 -44.3  275  67 34   7.6   4.1 | -43.2 -45.8  270  67 35   7.8   4.3
 27000 -40.1 -40.2  280  64 33   7.5   4.1 | -40.9 -41.6  270  62 32   7.8   4.3
 26000 -37.8 -36.0  280  62 32   8.1   4.5 | -38.6 -37.5  270  58 30   7.5   4.1
 25000 -34.7 -30.5  280  60 31   8.1   4.5 | -35.8 -32.4  275  55 28   7.5   4.1
 24000 -32.3 -26.1  280  58 30   8.3   4.6 | -33.6 -28.5  275  52 27   7.4   4.1
 23000 -30.2 -22.4  280  53 27   6.6   3.6 | -31.2 -24.2  275  50 26   8.2   4.5
 22000 -28.2 -18.8  275  47 24   6.6   3.6 | -28.8 -19.8  275  47 24   8.2   4.5
 21000 -26.3 -15.3  275  41 21   7.2   4.0 | -26.4 -15.5  280  44 23   7.9   4.3
 20000 -23.8 -10.8  275  37 19   8.1   4.5 | -24.2 -11.6  280  43 22   7.2   3.9
 19500 -22.6  -8.7  275  34 18   8.1   4.5 | -23.1  -9.6  285  42 22   7.2   3.9
 19000 -21.4  -6.5  275  32 16   8.1   4.5 | -22.1  -7.8  285  42 22   7.2   3.9
 18500 -20.2  -4.4  280  30 15   8.3   4.6 | -21.0  -5.8  285  42 21   7.3   4.0
 18000 -18.9  -2.0  275  28 15   9.0   4.9 | -19.7  -3.5  285  40 21   9.3   5.1
 17500 -17.5   0.5  275  27 14   9.0   4.9 | -18.4  -1.1  285  37 19   9.2   5.0
 17000 -16.2   2.8  275  26 13   8.6   4.7 | -17.0   1.4  280  35 18   8.3   4.6
 16500 -14.9   5.2  280  24 12   8.5   4.7 | -15.8   3.6  280  35 18   8.1   4.5
 16000 -13.6   7.5  280  22 11   8.3   4.6 | -14.6   5.7  280  34 18   8.3   4.6
 15500 -12.4   9.7  285  20 10   8.1   4.5 | -13.3   8.1  280  33 17   8.7   4.8
 15000 -11.2  11.8  290  19 10   8.1   4.5 | -12.0  10.4  275  31 16   8.7   4.8
 14500 -10.0  14.0  295  18  9   8.1   4.5 | -10.7  12.7  275  30 15   9.4   5.2
 14000  -8.8  16.2  300  18  9   8.1   4.5 |  -9.3  15.3  275  28 14   9.6   5.3
 13500  -7.6  18.3  305  19 10   7.9   4.4 |  -8.0  17.6  275  26 14   7.6   4.2
 13000  -6.4  20.5  310  20 10   8.0   4.4 |  -6.8  19.8  285  26 14   7.7   4.2
 12500  -5.3  22.5  310  22 11   7.7   4.2 |  -5.7  21.7  290  27 14   7.8   4.3
 12000  -4.2  24.4  315  24 12   6.8   3.7 |  -4.6  23.7  295  27 14   6.4   3.5
 11750  -3.7  25.3  315  25 13   6.8   3.7 |  -4.2  24.4  295  28 14   6.4   3.5
 11500  -3.2  26.2  315  26 13   7.3   4.0 |  -3.7  25.3  300  28 14   7.2   4.0
 11250  -2.7  27.1  315  27 14   7.5   4.1 |  -3.2  26.2  300  27 14   7.5   4.1
 11000  -2.1  28.2  315  27 14   6.9   3.8 |  -2.6  27.3  300  26 13   7.2   3.9
 10750  -1.7  28.9  315  29 15   6.2   3.4 |  -2.1  28.2  300  25 13   6.7   3.7
 10500  -1.2  29.8  315  28 15   6.6   3.6 |  -1.7  28.9  300  24 12   6.7   3.7
 10250  -0.7  30.7  315  28 14   6.7   3.7 |  -1.2  29.8  295  22 11   6.7   3.7
 10000  -0.2  31.6  315  27 14   6.5   3.6 |  -0.7  30.7  295  20 10   6.7   3.7
  9750   0.8  33.4  315  25 13   7.4   4.0 |   0.3  32.5  295  17  9   7.0   3.8
  9500   1.3  34.3  315  23 12   6.9   3.8 |   0.8  33.4  290  15  8   6.8   3.7
  9250   1.8  35.2  320  21 11   7.1   3.9 |   1.3  34.3  290  13  7   7.1   3.9
  9000   2.4  36.3  320  19 10   6.3   3.5 |   1.8  35.2  285  11  6   5.9   3.2
  8750   2.8  37.0  325  18  9   5.0   2.8 |   2.2  36.0  280   9  4   5.0   2.7
  8500   3.1  37.6  325  16  8   5.6   3.0 |   2.6  36.7  275   7  3   5.5   3.0
  8250   3.5  38.3  330  14  7   3.2   1.7 |   3.0  37.4  260   5  2   5.5   3.0
  8000   3.5  38.3  330  14  7  -2.0  -1.1 |   3.3  37.9  240   4  2   5.7   3.1
  7750   3.0  37.4  330  13  7 -14.3  -7.8 |   3.8  38.8  235   3  2   7.4   4.1
  7500   1.2  34.2  325  10  5 -30.5 -16.7 |   4.3  39.7  215   2  1  10.0   5.5
  7250  -0.7  30.7  310   6  3  -1.8  -1.0 |   4.8  40.6  190   2  1   6.1   3.4
  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

           02/20/2015 at 1400 MST          |       02/20/2015 at 1700 MST
                                           |
K index... +18.1  LI... -3.0               | K index... +14.0  LI... -0.7
CAPE... +393.2  CIN... -6.5                | CAPE... +72.5  CIN... -13.0
                                           |
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  285  38 20   0.4   0.2 | -56.6 -69.9  285  40 20   0.7   0.4
 45000 -55.9 -68.6  280  72 37   0.4   0.2 | -55.6 -68.1  280  58 30   0.7   0.4
 40000 -56.0 -68.8  280  74 38  -0.1  -0.0 | -53.9 -65.0  280  68 35   1.2   0.6
 38000 -55.8 -68.4  280  78 40   1.3   0.7 | -53.3 -63.9  280  74 38   0.0   0.0
 36000 -55.0 -67.0  280  93 48   1.3   0.7 | -53.3 -63.9  280  90 46   0.0   0.0
 34000 -54.2 -65.6  280 108 56   1.4   0.8 | -53.3 -63.9  285 106 55  -0.8  -0.4
 32000 -50.8 -59.4  280 104 54   6.1   3.4 | -50.0 -58.0  280 111 57   6.3   3.4
 30000 -47.1 -52.8  275  98 50   6.1   3.3 | -46.2 -51.2  280 115 59   6.2   3.4
 29000 -45.4 -49.7  275  94 48   5.3   2.9 | -44.0 -47.2  285 111 57   7.6   4.2
 28000 -43.8 -46.8  280  90 46   5.3   2.9 | -41.8 -43.2  285 106 55   7.6   4.2
 27000 -42.2 -44.0  280  86 44   5.4   3.0 | -39.5 -39.1  285 102 52   7.6   4.2
 26000 -40.3 -40.5  280  82 42   8.3   4.5 | -37.6 -35.7  285  93 48   2.7   1.5
 25000 -37.2 -35.0  280  78 40   8.2   4.5 | -36.7 -34.1  285  77 39   3.2   1.7
 24000 -34.8 -30.6  280  74 38   8.2   4.5 | -35.5 -31.9  285  56 29   3.3   1.8
 23000 -32.5 -26.5  275  67 35   7.6   4.2 | -34.1 -29.4  285  44 23   6.5   3.6
 22000 -30.2 -22.4  275  57 30   7.6   4.2 | -32.1 -25.8  285  38 20   6.6   3.6
 21000 -27.9 -18.2  270  48 25   7.6   4.2 | -30.2 -22.4  285  33 17   6.5   3.5
 20000 -25.6 -14.1  270  47 24   7.9   4.3 | -27.9 -18.2  285  31 16   8.2   4.5
 19500 -24.5 -12.1  270  47 24   7.9   4.3 | -26.7 -16.1  290  31 16   8.2   4.5
 19000 -23.3  -9.9  270  47 24   7.9   4.3 | -25.4 -13.7  290  31 16   8.2   4.5
 18500 -22.1  -7.8  270  47 24   7.8   4.3 | -24.2 -11.6  290  31 16   8.2   4.5
 18000 -20.9  -5.6  270  46 23   8.7   4.8 | -23.0  -9.4  290  31 16   8.0   4.4
 17500 -19.6  -3.3  270  43 22   8.6   4.7 | -21.8  -7.2  290  31 16   8.0   4.4
 17000 -18.4  -1.1  270  40 20   8.3   4.5 | -20.6  -5.1  295  31 16   7.8   4.3
 16500 -17.2   1.0  275  39 20   8.1   4.4 | -19.6  -3.3  295  32 16   7.3   4.0
 16000 -16.0   3.2  275  39 20   8.2   4.5 | -18.5  -1.3  300  33 17   7.4   4.0
 15500 -14.7   5.5  275  37 19   8.6   4.7 | -17.4   0.7  300  32 17   7.6   4.2
 15000 -13.4   7.9  275  35 18   8.6   4.7 | -16.2   2.8  305  32 16   7.6   4.2
 14500 -12.2  10.0  275  34 18   8.5   4.7 | -15.1   4.8  305  31 16   7.8   4.3
 14000 -10.9  12.4  280  35 18   8.5   4.7 | -14.0   6.8  305  30 16   7.9   4.3
 13500  -9.6  14.7  280  35 18   8.7   4.8 | -12.8   9.0  305  30 15   7.8   4.3
 13000  -8.4  16.9  280  33 17   8.7   4.8 | -11.7  10.9  305  30 15   7.8   4.3
 12500  -7.0  19.4  275  30 16  10.0   5.5 | -10.5  13.1  310  30 15   9.0   4.9
 12000  -5.7  21.7  275  27 14   7.2   4.0 |  -9.1  15.6  310  30 16   7.9   4.3
 11750  -5.2  22.6  275  25 13   7.0   3.8 |  -8.6  16.5  315  30 16   6.8   3.7
 11500  -4.7  23.5  270  23 12   8.6   4.7 |  -8.1  17.4  315  30 16   7.9   4.3
 11250  -4.0  24.8  270  22 11   9.3   5.1 |  -7.5  18.5  315  30 15   8.3   4.6
 11000  -3.4  25.9  270  20 10   9.2   5.1 |  -6.9  19.6  320  30 15   8.3   4.5
 10750  -2.7  27.1  270  19 10   9.2   5.0 |  -6.3  20.7  320  29 15   8.1   4.5
 10500  -2.0  28.4  265  17  9   8.5   4.6 |  -5.7  21.7  320  29 15   6.9   3.8
 10250  -1.4  29.5  265  16  8   8.1   4.5 |  -5.3  22.5  325  28 14   6.3   3.4
 10000  -0.8  30.6  260  15  8   8.1   4.4 |  -4.8  23.4  325  27 14   6.3   3.4
  9750   0.5  32.9  255  13  7   9.6   5.3 |  -3.8  25.2  330  26 14   6.6   3.6
  9500   1.1  34.0  255  13  6   8.6   4.7 |  -3.4  25.9  335  26 13   5.5   3.0
  9250   1.8  35.2  250  12  6   9.0   4.9 |  -3.0  26.6  340  26 13   6.1   3.4
  9000   2.4  36.3  245  11  6   8.6   4.7 |  -2.6  27.3  340  26 13   4.6   2.5
  8750   3.1  37.6  245  11  5   9.0   4.9 |  -2.3  27.9  345  27 14   5.7   3.1
  8500   3.8  38.8  245  10  5   9.6   5.3 |  -1.8  28.8  350  27 14   8.0   4.4
  8250   4.5  40.1  240   9  5   9.5   5.2 |  -1.2  29.8  350  27 14   7.4   4.1
  8000   5.2  41.4  240   8  4   9.6   5.3 |  -0.6  30.9  350  27 14   9.3   5.1
  7750   5.9  42.6  240   8  4  10.7   5.9 |   0.1  32.2  350  26 13  11.0   6.0
  7500   6.6  43.9  235   6  3  12.5   6.8 |   0.9  33.6  355  22 11  10.4   5.7
  7250   7.4  45.3  230   5  3   9.7   5.3 |   1.7  35.1  355  18  9  12.4   6.8
  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
________________________________________________________________________________

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.