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 15 16 17 18
000
UXUS97 KPUB 231147
SRGPUB

Soaring Forecast
National Weather Service Pueblo, Colorado
0447 MST Monday, January 23, 2017

This forecast is for Monday, January 23, 2017:

If the trigger temperature of 51.2 F/10.7 C is reached...then
   Thermal Soaring Index....................... Poor
   Maximum rate of lift........................ 124 ft/min (0.6 m/s)
   Maximum height of thermals.................. 8692 ft MSL (1521 ft AGL)

Forecast maximum temperature................... 46.0 F/8.2 C
Time of trigger temperature.................... None
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................. 7911 ft MSL (740 ft AGL)
Thermal soaring outlook for Tuesday 01/24...... Poor

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

Remarks...

Sunrise/Sunset.................... 07:11:48 / 17:09:11 MST
Total possible sunshine........... 9 hr 57 min 24 sec (597 min 24 sec)
Altitude of sun at 12:10:52 MST... 31.85 degrees

Upper air data from numerical model forecast valid on 01/23/2017 at 0500 MST

Freezing level.................. 7362 ft MSL (191 ft AGL)
Additional freezing level....... 10604 ft MSL (3433 ft AGL)
Convective condensation level... 16111 ft MSL (8940 ft AGL)
Lifted condensation level....... 14059 ft MSL (6888 ft AGL)
Lifted index.................... +9.9
K index......................... -7.2

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  -62.4 -80.3   250   59   30   2.4   1.3      M     M       M      M    M
 45000  -58.9 -74.0   270   79   41   2.9   1.6      M     M       M      M    M
 40000  -53.1 -63.6   265  119   61   3.7   2.0      M     M       M      M    M
 38000  -51.1 -60.0   265  127   65   3.3   1.8      M     M       M      M    M
 36000  -49.1 -56.4   265  130   67   3.3   1.8      M     M       M      M    M
 34000  -46.9 -52.4   260  133   68   6.5   3.5      M     M       M      M    M
 32000  -43.2 -45.8   265  129   66   6.1   3.4      M     M       M      M    M
 30000  -39.5 -39.1   265  125   64   7.3   4.0   32.0  89.6    18.5      M    M
 29000  -37.4 -35.3   265  123   64   7.1   3.9   30.8  87.5    17.9      M    M
 28000  -35.2 -31.4   265  122   63   7.1   3.9   29.8  85.7    17.3      M    M
 27000  -33.1 -27.6   265  120   62   7.2   4.0   28.9  84.1    16.8      M    M
 26000  -30.9 -23.6   270  115   59   5.1   2.8   27.0  80.6    15.5      M    M
 25000  -29.4 -20.9   270  110   56   5.1   2.8   25.3  77.5    14.3      M    M
 24000  -27.9 -18.2   275  104   54   5.2   2.8   23.7  74.6    13.1      M    M
 23000  -26.4 -15.5   275   97   50   4.7   2.6   21.8  71.3    11.8      M    M
 22000  -25.0 -13.0   275   89   46   4.7   2.6   20.0  68.0    10.3      M    M
 21000  -23.6 -10.5   275   80   41   4.8   2.7   18.3  65.0     9.0      M    M
 20000  -21.9  -7.4   270   75   39   5.9   3.2   16.8  62.3     7.8      M    M
 19500  -21.0  -5.8   270   73   38   5.9   3.2   16.2  61.1     7.3      M    M
 19000  -20.1  -4.2   270   71   36   5.9   3.2   15.5  59.9     6.8      M    M
 18500  -19.3  -2.7   270   69   35   5.7   3.1   14.9  58.8     6.2      M    M
 18000  -18.2  -0.8   270   66   34   7.8   4.3   14.4  57.9     5.8      M    M
 17500  -17.1   1.2   265   64   33   7.6   4.2   14.0  57.3     5.5      M    M
 17000  -16.0   3.2   265   62   32   8.1   4.4   13.7  56.6     5.3      M    M
 16500  -14.7   5.5   265   59   30   8.4   4.6   13.5  56.2     5.1      M    M
 16000  -13.5   7.7   260   55   28   8.4   4.6   13.3  55.9     4.9      M    M
 15500  -12.3   9.9   260   51   26   7.7   4.2   12.9  55.3     4.6      M    M
 15000  -11.2  11.8   260   48   25   7.9   4.3   12.6  54.7     4.2      M    M
 14500  -10.1  13.8   260   44   22   7.6   4.2   12.3  54.1     3.9      M    M
 14000   -9.0  15.8   260   40   20   7.7   4.2   12.0  53.5     3.6      M    M
 13500   -7.9  17.8   265   36   18   8.0   4.4   11.6  53.0     3.3      M    M
 13000   -6.7  19.9   265   32   17   8.0   4.4   11.4  52.5     3.0      M    M
 12500   -5.4  22.3   265   29   15  10.8   5.9   11.2  52.2     2.9      M    M
 12000   -3.8  25.2   265   27   14   8.1   4.5   11.3  52.4     3.0      M    M
 11750   -3.2  26.2   265   24   12   7.7   4.3   11.1  52.1     2.8      M    M
 11500   -2.6  27.3   270   22   11   9.1   5.0   11.0  51.9     2.7      M    M
 11250   -1.9  28.6   270   22   11  10.2   5.6   11.0  51.9     2.8      M    M
 11000   -1.2  29.8   270   21   11   8.9   4.9   11.0  51.9     2.8      M    M
 10750   -0.6  30.9   270   21   11   7.3   4.0   10.9  51.6     2.6      M    M
 10500   -0.0  32.0   270   20   11   7.2   4.0   10.7  51.3     2.4      M    M
 10250    0.5  32.9   270   22   11   7.2   3.9   10.5  50.9     2.2      M    M
 10000    1.6  34.9   270   24   12   6.2   3.4   10.1  50.2     1.9      M    M
  9750    2.0  35.6   270   26   13   5.1   2.8    9.8  49.6     1.5      M    M
  9500    2.4  36.3   270   28   14   5.3   2.9    9.4  49.0     1.2      M    M
  9250    2.7  36.9   270   30   15   5.7   3.1    9.1  48.4     0.8      M    M
  9000    3.1  37.6   270   32   16   4.0   2.2    8.8  47.8     0.5      M    M
  8750    3.2  37.8   270   33   17  -1.2  -0.7    8.1  46.6    -0.1    122  0.6
  8500    3.0  37.4   270   34   18  -3.6  -2.0    7.2  44.9    -1.1    122  0.6
  8250    2.8  37.0   270   35   18  -2.3  -1.3    6.2  43.1    -2.0    121  0.6
  8000    2.5  36.5   265   37   19  -5.0  -2.8    5.2  41.4    -3.0    121  0.6
  7750    1.8  35.2   270   29   15 -14.9  -8.2    3.8  38.8    -4.5    135  0.7
  7500    0.3  32.5   270   21   11 -23.4 -12.9    1.5  34.8    -6.7    173  0.9
  7250   -1.2  29.8   270   12    6 -10.6  -5.8   -0.7  30.8    -9.0    211  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 * * * * * *

           01/23/2017 at 0800 MST          |       01/23/2017 at 1100 MST
                                           |
K index... -2.5  LI... +2.4                | K index... -15.9  LI... +2.9
CAPE... 0.0  CIN... M                      | 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 -60.6 -77.1  250  66 34   2.8   1.6 | -60.7 -77.3  240  50 26   2.6   1.4
 45000 -56.3 -69.3  260  88 45   3.1   1.7 | -56.7 -70.1  245  49 25   3.0   1.7
 40000 -50.6 -59.1  260 114 58   3.7   2.0 | -50.2 -58.4  255 101 52   4.2   2.3
 38000 -49.1 -56.4  260 124 64   1.2   0.7 | -48.7 -55.7  255 118 61   0.6   0.3
 36000 -48.4 -55.1  260 134 69   1.2   0.7 | -48.3 -54.9  255 133 68   0.6   0.3
 34000 -47.4 -53.3  260 144 74   5.5   3.0 | -47.9 -54.2  255 147 75   4.1   2.3
 32000 -43.6 -46.5  260 142 73   6.4   3.5 | -44.4 -47.9  255 146 75   5.8   3.2
 30000 -39.8 -39.6  260 140 72   5.7   3.1 | -40.9 -41.6  260 145 75   5.4   2.9
 29000 -38.3 -36.9  265 135 70   4.9   2.7 | -39.5 -39.1  260 138 71   4.6   2.5
 28000 -36.8 -34.2  265 130 67   4.9   2.7 | -38.1 -36.6  260 132 68   4.6   2.5
 27000 -35.4 -31.7  265 126 65   4.9   2.7 | -36.7 -34.1  265 125 64   4.7   2.6
 26000 -33.6 -28.5  270 118 61   4.7   2.6 | -35.2 -31.4  265 119 61   5.7   3.1
 25000 -32.1 -25.8  270 111 57   4.7   2.6 | -33.0 -27.4  265 111 57   5.8   3.2
 24000 -30.7 -23.3  270 104 53   4.7   2.6 | -31.3 -24.3  265 105 54   5.7   3.2
 23000 -29.0 -20.2  275  97 50   6.6   3.6 | -29.4 -20.9  265  98 50   6.8   3.7
 22000 -27.0 -16.6  275  89 46   6.6   3.6 | -27.4 -17.3  265  91 47   6.8   3.7
 21000 -25.0 -13.0  275  81 42   6.6   3.6 | -25.3 -13.5  265  83 43   6.8   3.7
 20000 -22.9  -9.2  270  72 37   7.2   4.0 | -23.3  -9.9  265  74 38   6.9   3.8
 19500 -21.8  -7.2  270  67 35   7.2   3.9 | -22.3  -8.1  260  70 36   6.9   3.8
 19000 -20.7  -5.3  270  62 32   7.2   4.0 | -21.2  -6.2  260  66 34   6.9   3.8
 18500 -19.6  -3.3  270  58 30   7.4   4.0 | -20.2  -4.4  255  61 32   6.8   3.7
 18000 -18.7  -1.7  265  54 28   5.7   3.1 | -19.1  -2.4  250  54 28   8.5   4.7
 17500 -17.8  -0.0  265  52 27   5.8   3.2 | -17.8  -0.0  240  41 21   8.5   4.7
 17000 -17.0   1.4  265  49 25   6.1   3.3 | -16.5   2.3  220  31 16   8.3   4.5
 16500 -16.0   3.2  265  47 24   6.4   3.5 | -15.3   4.5  225  31 16   7.9   4.3
 16000 -15.1   4.8  265  45 23   6.5   3.6 | -14.1   6.6  230  31 16   7.9   4.3
 15500 -14.0   6.8  265  43 22   7.8   4.3 | -13.0   8.6  235  31 16   7.5   4.1
 15000 -12.9   8.8  265  41 21   7.6   4.2 | -11.9  10.6  240  32 16   7.6   4.2
 14500 -11.7  10.9  265  40 20   8.5   4.7 | -10.8  12.6  245  33 17   6.0   3.3
 14000 -10.5  13.1  265  40 20   8.5   4.6 |  -9.9  14.2  250  34 17   5.9   3.3
 13500  -9.2  15.4  265  39 20   8.7   4.8 |  -9.1  15.6  255  36 18   5.8   3.2
 13000  -7.9  17.8  265  40 20   8.7   4.8 |  -8.2  17.2  260  39 20   5.8   3.2
 12500  -6.6  20.1  265  40 21  10.2   5.6 |  -7.4  18.7  265  41 21   6.5   3.6
 12000  -5.2  22.6  260  40 21   6.9   3.8 |  -6.4  20.5  265  44 22   5.0   2.7
 11750  -4.7  23.5  260  40 21   5.9   3.3 |  -6.1  21.0  270  45 23   4.0   2.2
 11500  -4.3  24.3  260  41 21   7.9   4.3 |  -5.8  21.6  270  46 24   5.4   3.0
 11250  -3.6  25.5  260  41 21   9.5   5.2 |  -5.3  22.5  270  47 24   6.7   3.7
 11000  -2.9  26.8  260  42 21   8.4   4.6 |  -4.9  23.2  270  47 24   6.1   3.3
 10750  -2.3  27.9  260  42 22   7.3   4.0 |  -4.5  23.9  270  48 25   5.2   2.9
 10500  -1.8  28.8  260  42 22   7.8   4.3 |  -4.1  24.6  270  48 25   6.2   3.4
 10250  -1.2  29.8  260  42 22   8.4   4.6 |  -3.6  25.5  270  47 24   7.3   4.0
 10000   0.0  32.0  260  43 22   7.8   4.3 |  -3.1  26.4  270  46 24   7.1   3.9
  9750   0.6  33.1  260  43 22   7.5   4.1 |  -2.1  28.2  270  44 23   7.3   4.0
  9500   1.1  34.0  260  42 22   7.7   4.2 |  -1.5  29.3  270  42 22   8.2   4.5
  9250   1.7  35.1  255  42 22   8.3   4.6 |  -0.9  30.4  265  40 21   7.9   4.3
  9000   2.3  36.1  255  42 21   5.8   3.2 |  -0.3  31.5  265  38 20   8.5   4.6
  8750   2.5  36.5  255  40 20   0.4   0.2 |   0.3  32.5  265  37 19   9.1   5.0
  8500   2.4  36.3  255  38 19  -1.2  -0.7 |   1.0  33.8  265  34 17   9.0   4.9
  8250   2.4  36.3  255  36 18  -0.1  -0.0 |   1.6  34.9  260  31 16   9.2   5.1
  8000   2.3  36.1  255  34 17  -3.0  -1.6 |   2.3  36.1  260  29 15   8.6   4.7
  7750   1.7  35.1  255  29 15 -15.3  -8.4 |   3.0  37.4  260  26 13  10.9   6.0
  7500   0.0  32.0  255  20 10 -27.1 -14.9 |   4.0  39.2  255  21 11  16.7   9.1
  7250  -1.6  29.1  260  11  6  -8.7  -4.8 |   5.0  41.0  255  17  9   6.0   3.3
  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

           01/23/2017 at 1400 MST          |       01/23/2017 at 1700 MST
                                           |
K index... +3.0  LI... +2.5                | K index... +9.0  LI... +0.7
CAPE... 0.0  CIN... M                      | CAPE... +5.5  CIN... -7.4
                                           |
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 -58.9 -74.0  240  44 23   3.5   1.9 | -58.3 -72.9  245  44 23   3.3   1.8
 45000 -53.7 -64.7  250  54 28   3.4   1.9 | -53.4 -64.1  245  58 30   3.5   1.9
 40000 -51.2 -60.2  250 103 53   1.6   0.9 | -50.3 -58.5  245  98 50   2.0   1.1
 38000 -50.2 -58.4  250 121 62   1.5   0.8 | -49.2 -56.6  245 112 58   1.3   0.7
 36000 -49.2 -56.6  250 133 69   1.5   0.8 | -48.3 -54.9  245 120 62   1.3   0.7
 34000 -48.3 -54.9  250 145 75   3.3   1.8 | -47.5 -53.5  250 128 66   1.5   0.8
 32000 -44.8 -48.6  250 144 74   5.8   3.2 | -45.0 -49.0  250 135 70   4.3   2.4
 30000 -41.3 -42.3  255 144 74   5.7   3.1 | -42.4 -44.3  250 142 73   4.2   2.3
 29000 -39.9 -39.8  255 139 72   4.8   2.6 | -40.9 -41.6  250 141 72   5.5   3.0
 28000 -38.4 -37.1  255 134 69   4.8   2.6 | -39.2 -38.6  250 138 71   5.5   3.0
 27000 -37.0 -34.6  260 130 67   4.8   2.7 | -37.6 -35.7  255 135 69   5.5   3.0
 26000 -35.4 -31.7  260 125 64   6.4   3.5 | -35.9 -32.6  255 131 68   6.2   3.4
 25000 -33.5 -28.3  260 120 62   6.3   3.5 | -34.1 -29.4  255 126 65   6.1   3.4
 24000 -31.6 -24.9  260 116 60   6.3   3.5 | -32.2 -26.0  255 122 63   6.1   3.4
 23000 -29.3 -20.7  260 107 55   5.8   3.2 | -30.0 -22.0  255 115 59   5.2   2.9
 22000 -27.6 -17.7  260  95 49   5.8   3.2 | -28.5 -19.3  250 108 56   5.3   2.9
 21000 -25.9 -14.6  255  83 43   5.7   3.1 | -26.9 -16.4  250 102 52   5.2   2.9
 20000 -23.9 -11.0  250  72 37   6.8   3.7 | -25.5 -13.9  250  93 48   4.4   2.4
 19500 -22.9  -9.2  250  66 34   6.8   3.8 | -24.8 -12.6  250  87 45   4.4   2.4
 19000 -21.9  -7.4  245  61 31   6.9   3.8 | -24.2 -11.6  250  82 42   4.5   2.4
 18500 -20.9  -5.6  245  56 29   6.9   3.8 | -23.5 -10.3  255  76 39   4.5   2.5
 18000 -19.9  -3.8  240  52 27   5.8   3.2 | -22.9  -9.2  255  71 36   5.4   3.0
 17500 -19.1  -2.4  245  53 28   5.4   3.0 | -21.9  -7.4  255  67 35   6.7   3.7
 17000 -18.3  -0.9  245  55 28   5.6   3.1 | -20.9  -5.6  255  64 33   6.7   3.7
 16500 -17.4   0.7  245  54 28   6.6   3.6 | -19.8  -3.6  255  59 31   7.9   4.3
 16000 -16.4   2.5  250  52 27   6.6   3.6 | -18.7  -1.7  255  53 27   7.8   4.3
 15500 -15.5   4.1  250  50 26   6.7   3.7 | -17.5   0.5  255  47 24   8.1   4.4
 15000 -14.5   5.9  250  47 24   6.7   3.7 | -16.3   2.7  255  44 23   8.2   4.5
 14500 -13.5   7.7  250  44 23   7.3   4.0 | -15.1   4.8  255  41 21   8.2   4.5
 14000 -12.4   9.7  250  41 21   7.5   4.1 | -13.9   7.0  255  38 19   8.2   4.5
 13500 -11.3  11.7  255  39 20   7.9   4.3 | -12.7   9.1  255  34 18   8.2   4.5
 13000 -10.1  13.8  250  37 19   8.2   4.5 | -11.5  11.3  250  32 16   8.0   4.4
 12500  -8.9  16.0  250  34 18   7.7   4.2 | -10.3  13.5  250  29 15   7.3   4.0
 12000  -7.7  18.1  250  32 16   8.2   4.5 |  -9.3  15.3  245  28 15   8.2   4.5
 11750  -7.1  19.2  250  31 16   8.6   4.7 |  -8.6  16.5  245  28 14   9.9   5.4
 11500  -6.5  20.3  245  29 15   8.2   4.5 |  -7.9  17.8  245  27 14   9.2   5.0
 11250  -5.9  21.4  245  28 15   7.6   4.2 |  -7.3  18.9  240  27 14   7.8   4.3
 11000  -5.4  22.3  245  27 14   7.5   4.1 |  -6.8  19.8  240  27 14   7.3   4.0
 10750  -4.8  23.4  240  26 13   7.4   4.1 |  -6.2  20.8  240  28 14   8.1   4.4
 10500  -4.3  24.3  240  25 13   7.3   4.0 |  -5.6  21.9  235  28 14   7.8   4.3
 10250  -3.8  25.2  235  24 12   7.1   3.9 |  -5.1  22.8  235  29 15   6.7   3.7
 10000  -3.3  26.1  235  23 12   7.0   3.8 |  -4.6  23.7  235  30 15   6.0   3.3
  9750  -2.7  27.1  235  22 11   7.3   4.0 |  -4.2  24.4  230  31 16   7.0   3.8
  9500  -1.7  28.9  225  19 10   7.5   4.1 |  -3.1  26.4  225  31 16   7.1   3.9
  9250  -1.1  30.0  225  18  9   7.0   3.8 |  -2.6  27.3  225  31 16   6.8   3.7
  9000  -0.6  30.9  220  17  9   9.1   5.0 |  -2.1  28.2  220  31 16   7.9   4.3
  8750   0.2  32.4  215  16  8  10.5   5.7 |  -1.5  29.3  220  31 16   8.9   4.9
  8500   0.9  33.6  215  16  8   9.3   5.1 |  -0.8  30.6  215  30 15   8.2   4.5
  8250   1.6  34.9  215  16  8   9.8   5.4 |  -0.2  31.6  215  29 15   8.6   4.7
  8000   2.3  36.1  210  15  8   8.9   4.9 |   0.4  32.7  210  27 14   7.0   3.8
  7750   3.0  37.4  210  15  8  11.8   6.5 |   0.7  33.3  210  25 13   2.5   1.4
  7500   4.2  39.6  205  14  7  19.2  10.5 |   0.8  33.4  205  19 10   0.2   0.1
  7250   5.3  41.5  205  12  6   5.5   3.0 |   0.9  33.6  200  14  7   2.7   1.5
  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.