Soaring Guidance
Issued by NWS Grand Junction, CO

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10
000
UXUS97 KGJT 011245
SRGGJT

Soaring Forecast
National Weather Service Grand Junction, Colorado
0645 MDT Wednesday, October 1, 2014

This forecast is for Wednesday, October 1, 2014:

If the trigger temperature of 63.7 F/17.6 C is reached...then
   Thermal Soaring Index....................... Poor
   Maximum rate of lift........................ 2 ft/min (0.0 m/s)
   Maximum height of thermals.................. 7816 ft MSL (2977 ft AGL)

Forecast maximum temperature................... 60.0 F/16.0 C
Time of trigger temperature.................... None
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................. 5562 ft MSL (723 ft AGL)
Thermal soaring outlook for Thursday 10/02..... Fair

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

Remarks...

Sunrise/Sunset.................... 07:10:13 / 18:58:13 MDT
Total possible sunshine........... 11 hr 48 min 1 sec (708 min 1 sec)
Altitude of sun at 13:03:44 MDT... 47.52 degrees

Upper air data from rawinsonde observation taken on 10/01/2014 at 0600 MDT

Freezing level.................. 11322 ft MSL (6483 ft AGL)
Convective condensation level... 11984 ft MSL (7145 ft AGL)
Lifted condensation level....... 10365 ft MSL (5526 ft AGL)
Lifted index.................... +2.1
K index......................... +25.3

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  -60.2 -76.4   255   45   23  -3.4  -1.9   99.2 210.5    47.8      M    M
 45000  -54.9 -66.8   275   54   28   5.3   2.9   82.2 179.9    40.9      M    M
 40000  -50.6 -59.1   265   73   38  -1.6  -0.9   65.8 150.5    33.0      M    M
 38000  -49.1 -56.4   260   91   47   3.7   2.1   59.4 138.9    29.5      M    M
 36000  -48.5 -55.3   260   74   38   5.4   3.0   51.7 125.0    25.0      M    M
 34000  -47.1 -52.8   260   68   35   4.5   2.5   45.3 113.5    21.1      M    M
 32000  -44.1 -47.4   255   66   34   4.5   2.5   40.4 104.7    18.1      M    M
 30000  -41.6 -42.9   260   48   25   5.6   3.1   35.8  96.5    15.2      M    M
 29000  -39.7 -39.5   265   36   19   6.8   3.7   34.4  94.0    14.3      M    M
 28000  -37.6 -35.7   265   35   18   8.7   4.8   33.4  92.2    13.7      M    M
 27000  -35.0 -31.0   260   34   18   8.7   4.8   33.0  91.5    13.6      M    M
 26000  -32.5 -26.5   260   34   17   8.0   4.4   32.5  90.5    13.3      M    M
 25000  -30.1 -22.2   255   33   17   8.4   4.6   32.0  89.5    13.0      M    M
 24000  -27.6 -17.7   250   34   17   8.2   4.5   31.4  88.5    12.7      M    M
 23000  -25.6 -14.1   250   33   17   5.2   2.8   30.4  86.7    12.0      M    M
 22000  -23.2  -9.8   250   32   16   8.1   4.5   29.7  85.5    11.5      M    M
 21000  -21.2  -6.2   245   31   16   4.8   2.6   28.6  83.4    10.7      M    M
 20000  -19.7  -3.5   245   30   15   3.3   1.8   26.9  80.3     9.4      M    M
 19500  -18.7  -1.7   245   31   16  10.2   5.6   26.3  79.3     9.0      M    M
 19000  -18.0  -0.4   240   33   17   0.8   0.4   25.4  77.7     8.3      M    M
 18500  -17.7   0.1   250   29   15   6.2   3.4   24.2  75.5     7.2      M    M
 18000  -15.8   3.6   245   29   15   7.7   4.2   23.8  74.8     6.9      M    M
 17500  -14.6   5.7   245   28   15   8.3   4.6   23.5  74.3     6.7      M    M
 17000  -13.4   7.9   245   28   15   8.4   4.6   23.3  73.9     6.5      M    M
 16500  -12.4   9.7   240   28   14   6.5   3.5   22.8  73.1     6.1      M    M
 16000  -11.4  11.5   240   28   14   6.6   3.6   22.4  72.2     5.7      M    M
 15500  -10.2  13.6   240   26   13  10.2   5.6   22.1  71.8     5.4      M    M
 15000   -9.0  15.8   240   24   12   5.4   3.0   21.8  71.2     5.2      M    M
 14500   -7.9  17.8   240   22   11   9.5   5.2   21.4  70.6     4.8      M    M
 14000   -6.5  20.3   240   20   10   9.1   5.0   21.3  70.4     4.8      M    M
 13500   -5.2  22.6   235   20   10   9.0   5.0   21.2  70.2     4.7      M    M
 13000   -3.9  25.0   235   19   10   7.8   4.3   21.0  69.8     4.5      M    M
 12500   -2.8  27.0   230   19   10   8.1   4.4   20.7  69.2     4.2      M    M
 12000   -1.7  28.9   230   19   10   8.1   4.5   20.4  68.8     3.9      M    M
 11500   -0.4  31.3   230   17    9   9.1   5.0   20.2  68.4     3.7      M    M
 11000    0.9  33.6   225   15    8   9.0   5.0   20.1  68.2     3.6      M    M
 10500    2.3  36.1   225   14    7   9.0   4.9   20.0  68.0     3.5      M    M
 10250    2.9  37.2   220   13    7   9.2   5.1   19.9  67.9     3.4      M    M
 10000    3.6  38.5   220   12    6   8.3   4.5   19.9  67.8     3.4      M    M
  9750    4.2  39.6   220   11    5   7.7   4.2   19.7  67.5     3.3      M    M
  9500    4.8  40.6   220    9    5   6.8   3.7   19.6  67.2     3.1      M    M
  9250    5.1  41.2   215    8    4   4.3   2.3   19.2  66.6     2.8      M    M
  9000    5.4  41.7   215    6    3   3.6   2.0   18.8  65.8     2.3      M    M
  8750    5.7  42.3   190    6    3   3.8   2.1   18.3  64.9     1.8      M    M
  8500    5.9  42.6   170    8    4   3.7   2.1   17.8  64.1     1.4      M    M
  8250    6.2  43.2   160   10    5   3.7   2.0   17.3  63.2     0.9      M    M
  8000    6.4  43.5   150   13    6   3.8   2.1   16.9  62.4     0.4      M    M
  7750    6.7  44.1   150   12    6   3.5   1.9   16.4  61.5    -0.0    201  1.0
  7500    6.9  44.4   145   10    5   4.9   2.7   16.0  60.7    -0.5    186  0.9
  7250    7.4  45.3   140    9    4   6.9   3.8   15.7  60.2    -0.8    165  0.8
  7000    7.9  46.2   130    7    4   6.9   3.8   15.5  59.8    -1.0    143  0.7
  6750    8.4  47.1   120    7    4   6.9   3.8   15.2  59.4    -1.3    120  0.6
  6500    8.9  48.0   110    7    4   7.0   3.8   15.0  59.0    -1.5     98  0.5
  6250    9.4  48.9   100    7    4   6.7   3.7   14.8  58.6    -1.7     76  0.4
  6000    9.9  49.8   090    8    4   7.6   4.2   14.6  58.3    -2.0     53  0.3
  5750   10.4  50.7   090    7    4   4.3   2.4   14.4  57.9    -2.2     31  0.2
  5500   10.4  50.7   100    5    3  -2.5  -1.4   13.7  56.6    -2.9     23  0.1
  5250   10.1  50.2   105    4    2  -4.7  -2.6   12.6  54.7    -4.0     26  0.1
  5000    9.7  49.5   125    3    1  -5.1  -2.8   11.5  52.8    -5.1     30  0.2

 * * * * * * Numerical weather prediction model forecast data valid * * * * * *

           10/01/2014 at 0900 MDT          |       10/01/2014 at 1200 MDT
                                           |
K index... +29.4  LI... -1.3               | K index... +20.9  LI... 0.0
CAPE... +129.7  CIN... -2.0                | CAPE... +26.3  CIN... -3.5
                                           |
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 -56.9 -70.4  260  31 16   2.2   1.2 | -57.6 -71.7  255  31 16   1.6   0.9
 45000 -53.5 -64.3  260  53 27   2.5   1.4 | -54.9 -66.8  260  54 28   2.9   1.6
 40000 -49.7 -57.5  260  79 41   2.5   1.4 | -50.5 -58.9  265  65 33   3.0   1.6
 38000 -48.7 -55.7  260  80 41   1.4   0.8 | -49.4 -56.9  265  66 34   1.2   0.6
 36000 -47.8 -54.0  260  77 40   1.4   0.8 | -48.7 -55.7  260  66 34   1.2   0.6
 34000 -46.8 -52.2  260  72 37   2.8   1.6 | -47.5 -53.5  260  65 34   4.9   2.7
 32000 -44.9 -48.8  255  57 29   2.8   1.5 | -44.2 -47.6  260  59 30   4.9   2.7
 30000 -42.4 -44.3  255  44 23   7.1   3.9 | -41.1 -42.0  255  54 28   5.9   3.3
 29000 -40.3 -40.5  255  38 19   7.1   3.9 | -39.3 -38.7  255  53 27   6.0   3.3
 28000 -38.2 -36.8  250  32 16   7.1   3.9 | -37.5 -35.5  255  52 27   5.9   3.3
 27000 -36.0 -32.8  245  27 14   8.5   4.7 | -35.7 -32.3  255  51 26   8.1   4.4
 26000 -33.4 -28.1  250  27 14   8.8   4.8 | -33.1 -27.6  250  50 26   8.7   4.8
 25000 -30.7 -23.3  250  27 14   8.8   4.8 | -30.5 -22.9  250  50 26   8.7   4.8
 24000 -28.1 -18.6  250  27 14   8.2   4.5 | -27.9 -18.2  245  49 25   7.9   4.3
 23000 -25.9 -14.6  255  29 15   7.6   4.2 | -25.9 -14.6  245  47 24   6.8   3.7
 22000 -23.6 -10.5  255  31 16   7.6   4.2 | -23.9 -11.0  245  45 23   6.8   3.7
 21000 -21.4  -6.5  255  33 17   7.3   4.0 | -21.9  -7.4  245  43 22   6.6   3.6
 20000 -19.2  -2.6  255  35 18   7.3   4.0 | -19.9  -3.8  250  42 22   6.6   3.6
 19500 -18.2  -0.8  255  36 19   7.4   4.0 | -18.9  -2.0  255  42 21   6.6   3.6
 19000 -17.1   1.2  250  37 19   7.4   4.0 | -17.9  -0.2  260  42 21   6.6   3.6
 18500 -16.0   3.2  250  38 20   7.3   4.0 | -16.9   1.6  260  41 21   6.9   3.8
 18000 -14.9   5.2  250  38 19   7.3   4.0 | -15.8   3.6  260  39 20   7.2   3.9
 17500 -13.9   7.0  250  37 19   7.3   4.0 | -14.8   5.4  260  38 19   7.2   3.9
 17000 -12.8   9.0  245  36 19   7.2   3.9 | -13.7   7.3  260  36 19   6.5   3.5
 16500 -11.8  10.8  245  35 18   7.2   4.0 | -12.8   9.0  260  35 18   6.5   3.5
 16000 -10.7  12.7  245  34 17   6.9   3.8 | -11.8  10.8  265  33 17   7.4   4.1
 15500  -9.2  15.4  240  31 16   6.9   3.8 | -10.7  12.7  265  32 16   7.6   4.2
 15000  -8.2  17.2  235  29 15   6.8   3.7 |  -9.1  15.6  270  30 15   6.0   3.3
 14500  -7.2  19.0  235  26 14   6.8   3.7 |  -8.2  17.2  270  27 14   6.3   3.4
 14000  -6.3  20.7  235  24 13   6.7   3.7 |  -7.3  18.9  275  25 13   6.3   3.5
 13500  -5.3  22.5  235  22 11   6.7   3.7 |  -6.4  20.5  280  24 12   6.3   3.5
 13000  -4.3  24.3  235  20 10   6.7   3.6 |  -5.5  22.1  285  22 11   6.6   3.6
 12500  -3.4  25.9  235  18  9   6.7   3.7 |  -4.5  23.9  290  21 11   6.8   3.7
 12000  -2.4  27.7  235  16  8   6.7   3.7 |  -3.5  25.7  290  19 10   6.6   3.6
 11500  -1.5  29.3  235  14  7   6.7   3.7 |  -2.6  27.3  290  18  9   6.5   3.6
 11000  -0.5  31.1  235  12  6   6.0   3.3 |  -1.7  28.9  290  17  9   6.3   3.5
 10500   0.3  32.5  230  11  6   4.6   2.5 |  -0.8  30.6  285  16  8   5.8   3.2
 10250   0.7  33.3  230  11  6   9.3   5.1 |  -0.4  31.3  285  16  8   8.4   4.6
 10000   1.5  34.7  230  11  6   9.4   5.2 |   0.3  32.5  285  15  8   7.8   4.3
  9750   1.9  35.4  230  11  5   4.7   2.6 |   0.7  33.3  285  14  7   4.6   2.5
  9500   2.3  36.1  230  10  5   6.0   3.3 |   1.1  34.0  290  13  6   5.7   3.1
  9250   2.7  36.9  230  10  5   5.6   3.0 |   1.4  34.5  290  11  6   4.6   2.5
  9000   3.1  37.6  230   9  5   5.6   3.1 |   1.7  35.1  290  10  5   4.8   2.6
  8750   3.5  38.3  230   8  4   5.5   3.0 |   2.2  36.0  295   9  5   5.8   3.2
  8500   3.9  39.0  225   7  4   5.6   3.1 |   2.6  36.7  300   8  4   5.4   3.0
  8250   4.4  39.9  225   7  3   5.3   2.9 |   3.0  37.4  310   6  3   6.1   3.3
  8000   4.7  40.5  225   6  3   5.0   2.7 |   3.5  38.3  320   5  3   6.3   3.5
  7750   5.1  41.2  230   5  2   5.1   2.8 |   3.9  39.0  335   4  2   5.5   3.0
  7500   5.5  41.9  240   4  2   5.2   2.8 |   4.3  39.7  005   4  2   5.9   3.3
  7250   5.9  42.6  245   3  2   6.0   3.3 |   4.8  40.6  025   4  2   7.4   4.1
  7000   6.4  43.5  255   3  2   6.1   3.3 |   5.3  41.5  040   4  2   8.3   4.6
  6750   6.8  44.2  265   3  1   4.6   2.5 |   5.9  42.6  045   4  2   8.0   4.4
  6500   7.1  44.8  280   2  1   4.2   2.3 |   6.5  43.7  045   4  2   9.7   5.3
  6250   7.4  45.3  300   2  1   4.6   2.5 |   7.3  45.1  050   4  2  11.5   6.3
  6000   7.7  45.9  325   2  1   4.3   2.4 |   8.1  46.6  050   3  2  10.6   5.8
  5750   8.0  46.4  350   2  1   4.0   2.2 |   8.9  48.0  050   3  2  10.9   6.0
  5500   8.3  46.9  355   2  1   4.8   2.6 |   9.8  49.6  050   3  2  12.9   7.1
  5250   8.7  47.7  345   2  1   6.0   3.3 |  10.7  51.3  045   3  2  13.9   7.6
  5000     M     M    M   M  M     M     M |     M     M    M   M  M     M     M

           10/01/2014 at 1500 MDT          |       10/01/2014 at 1800 MDT
                                           |
K index... +6.1  LI... +0.4                | K index... +7.4  LI... +2.3
CAPE... +101.7  CIN... -2.9                | CAPE... +57.4  CIN... -7.9
                                           |
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 -57.2 -71.0  260  35 18   1.6   0.9 | -57.0 -70.6  270  32 17   2.2   1.2
 45000 -54.5 -66.1  260  53 27   2.7   1.5 | -53.5 -64.3  275  49 25   1.8   1.0
 40000 -50.4 -58.7  265  44 23   2.8   1.5 | -50.8 -59.4  260  40 21   1.8   1.0
 38000 -49.6 -57.3  260  47 24   0.4   0.2 | -49.9 -57.8  260  40 21   1.2   0.7
 36000 -49.4 -56.9  260  54 28   0.4   0.2 | -49.2 -56.6  265  41 21   1.2   0.7
 34000 -48.6 -55.5  260  59 30   5.2   2.8 | -48.1 -54.6  270  42 22   4.3   2.3
 32000 -45.5 -49.9  255  56 29   5.1   2.8 | -45.3 -49.5  265  43 22   4.1   2.3
 30000 -41.7 -43.1  255  53 27   6.9   3.8 | -42.4 -44.3  265  42 22   6.5   3.6
 29000 -39.7 -39.5  255  50 26   6.9   3.8 | -40.5 -40.9  265  41 21   6.6   3.6
 28000 -37.6 -35.7  255  47 24   6.9   3.8 | -38.5 -37.3  265  39 20   6.6   3.6
 27000 -35.4 -31.7  255  45 23   7.8   4.3 | -36.4 -33.5  265  38 19   7.8   4.3
 26000 -33.1 -27.6  255  42 22   7.9   4.4 | -34.0 -29.2  270  37 19   8.2   4.5
 25000 -30.7 -23.3  255  40 21   7.9   4.4 | -31.5 -24.7  270  36 19   8.2   4.5
 24000 -28.3 -18.9  260  38 20   7.9   4.4 | -29.1 -20.4  275  35 18   8.4   4.6
 23000 -25.9 -14.6  255  39 20   8.0   4.4 | -26.5 -15.7  270  37 19   8.6   4.7
 22000 -23.5 -10.3  255  39 20   8.0   4.4 | -23.9 -11.0  270  38 20   8.6   4.7
 21000 -21.2  -6.2  255  40 21   7.1   3.9 | -21.4  -6.5  265  40 20   8.3   4.6
 20000 -19.1  -2.4  255  41 21   7.0   3.9 | -18.9  -2.0  270  39 20   8.3   4.5
 19500 -18.0  -0.4  255  42 21   7.0   3.9 | -17.6   0.3  270  38 20   8.3   4.5
 19000 -17.0   1.4  255  42 22   7.1   3.9 | -16.4   2.5  270  38 20   8.2   4.5
 18500 -15.9   3.4  255  43 22   6.6   3.6 | -15.2   4.6  270  38 19   6.0   3.3
 18000 -15.0   5.0  260  41 21   6.3   3.5 | -14.5   5.9  270  36 18   4.4   2.4
 17500 -14.0   6.8  260  39 20   6.3   3.4 | -13.9   7.0  270  34 17   4.3   2.4
 17000 -13.2   8.2  260  37 19   4.6   2.5 | -13.4   7.9  270  32 16   2.3   1.3
 16500 -12.5   9.5  265  34 17   4.7   2.6 | -13.0   8.6  270  29 15   2.4   1.3
 16000 -11.8  10.8  265  31 16   5.0   2.7 | -12.6   9.3  265  27 14   4.2   2.3
 15500 -11.0  12.2  265  28 15   5.0   2.8 | -11.9  10.6  265  25 13   4.7   2.6
 15000 -10.3  13.5  260  26 13   5.2   2.9 | -10.8  12.6  265  23 12   6.2   3.4
 14500  -9.2  15.4  260  25 13   5.6   3.0 |  -9.9  14.2  260  21 11   6.1   3.4
 14000  -8.3  17.1  260  24 12   6.9   3.8 |  -9.0  15.8  255  20 10   7.9   4.3
 13500  -7.4  18.7  260  23 12   7.1   3.9 |  -7.8  18.0  255  20 10   8.1   4.5
 13000  -6.3  20.7  260  22 12   8.3   4.5 |  -6.6  20.1  250  19 10   8.6   4.7
 12500  -5.1  22.8  260  20 11   8.6   4.7 |  -5.4  22.3  250  19 10   8.8   4.8
 12000  -3.9  25.0  265  19 10   8.2   4.5 |  -4.1  24.6  250  19 10   8.1   4.5
 11500  -2.7  27.1  265  17  9   8.0   4.4 |  -3.0  26.6  255  19 10   7.9   4.3
 11000  -1.6  29.1  270  15  7   6.7   3.7 |  -1.9  28.6  260  18  9   7.0   3.8
 10500  -0.7  30.7  270  13  7   5.4   3.0 |  -1.0  30.2  265  17  9   6.0   3.3
 10250  -0.2  31.6  275  12  6   9.2   5.1 |  -0.5  31.1  265  17  9   9.4   5.1
 10000   0.6  33.1  275  12  6   9.6   5.3 |   0.3  32.5  265  16  8  10.0   5.5
  9750   1.1  34.0  275  11  6   5.9   3.2 |   0.9  33.6  270  15  8   7.0   3.8
  9500   1.5  34.7  275  11  5   7.1   3.9 |   1.4  34.5  270  14  7   7.9   4.3
  9250   2.0  35.6  280  10  5   6.1   3.4 |   2.0  35.6  275  13  7   7.3   4.0
  9000   2.5  36.5  280   9  5   6.4   3.5 |   2.5  36.5  275  12  6   8.1   4.4
  8750   3.0  37.4  280   8  4   7.3   4.0 |   3.1  37.6  280  11  6   9.0   4.9
  8500   3.5  38.3  280   7  4   6.7   3.7 |   3.8  38.8  280  10  5   8.6   4.7
  8250   3.9  39.0  275   6  3   8.1   4.5 |   4.4  39.9  280   9  5   9.2   5.0
  8000   4.6  40.3  275   5  3   9.4   5.2 |   5.1  41.2  285   9  5   9.4   5.2
  7750   5.2  41.4  275   5  3   9.0   5.0 |   5.7  42.3  285   9  5   9.0   4.9
  7500   5.9  42.6  280   5  3   9.3   5.1 |   6.4  43.5  285   9  4   9.2   5.1
  7250   6.6  43.9  280   5  2  10.0   5.5 |   7.1  44.8  285   9  4  10.1   5.6
  7000   7.4  45.3  280   5  2  10.2   5.6 |   7.9  46.2  285   8  4  10.1   5.6
  6750   8.1  46.6  280   5  2   9.4   5.1 |   8.6  47.5  285   8  4   8.8   4.8
  6500   8.8  47.8  275   5  2  10.4   5.7 |   9.3  48.7  285   8  4   9.4   5.2
  6250   9.6  49.3  275   5  2  11.8   6.5 |  10.0  50.0  285   8  4  10.5   5.8
  6000  10.5  50.9  275   5  2  11.0   6.1 |  10.8  51.4  285   8  4  10.3   5.6
  5750  11.3  52.3  275   4  2  10.9   6.0 |  11.5  52.7  285   8  4   9.2   5.1
  5500  12.1  53.8  275   4  2  12.5   6.8 |  12.2  54.0  285   7  4   7.7   4.2
  5250  13.1  55.6  275   4  2  13.8   7.6 |  12.7  54.9  285   7  4   7.5   4.1
  5000     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 at Walker Field in Grand
Junction, Colorado at

                   North Latitude:  39 deg 07 min 0.000 sec
                   West Longitude: 108 deg 32 min 0.000 sec
                   Elevation: 4839 feet (1475 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.