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 11 12 13 14
000
UXUS97 KGJT 271233
SRGGJT

Soaring Forecast
National Weather Service Grand Junction, Colorado
0633 MDT Wednesday, August 27, 2014

This forecast is for Wednesday, August 27, 2014:

If the trigger temperature of 68.9 F/20.5 C is reached...then
   Thermal Soaring Index....................... Fair
   Maximum rate of lift........................ 325 ft/min (1.7 m/s)
   Maximum height of thermals.................. 11575 ft MSL (6736 ft AGL)

Forecast maximum temperature................... 73.0 F/23.2 C
Time of trigger temperature.................... 1100 MDT
Time of overdevelopment........................ 0700 MDT
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................. 7796 ft MSL (2957 ft AGL)
Thermal soaring outlook for Thursday 08/28..... Good

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

Remarks...

Sunrise/Sunset.................... 06:38:19 / 19:53:31 MDT
Total possible sunshine........... 13 hr 15 min 12 sec (795 min 12 sec)
Altitude of sun at 13:15:30 MDT... 60.76 degrees

Upper air data from rawinsonde observation taken on 08/27/2014 at 0600 MDT

Freezing level.................. 12919 ft MSL (8080 ft AGL)
Convective condensation level... 9466 ft MSL (4627 ft AGL)
Lifted condensation level....... 10205 ft MSL (5366 ft AGL)
Lifted index.................... -2.8
K index......................... +31.5

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  -60.3 -76.5   245   19   10   7.4   4.1   96.2 205.1    42.3      M    M
 45000  -59.1 -74.4   215   67   35  -0.3  -0.2   72.7 162.8    30.9      M    M
 40000  -53.3 -63.9   215   57   30   5.1   2.8   58.8 137.8    23.9      M    M
 38000  -49.7 -57.5   210   61   32   6.6   3.6   55.2 131.3    22.1      M    M
 36000  -45.8 -50.4   205   66   34   6.7   3.7   52.5 126.6    20.8      M    M
 34000  -40.7 -41.3   205   67   35   9.3   5.1   51.4 124.6    20.5      M    M
 32000  -34.4 -29.9   210   67   34  10.2   5.6   51.2 124.2    21.0      M    M
 30000  -33.1 -27.6   200   41   21   6.0   3.3   45.2 113.3    16.9      M    M
 29000  -31.6 -24.9   200   38   19   1.5   0.8   43.3 109.9    15.7      M    M
 28000  -30.3 -22.5   200   34   18   6.9   3.8   41.1 106.0    14.2      M    M
 27000  -28.2 -18.8   200   31   16   7.1   3.9   40.1 104.2    13.5      M    M
 26000  -26.1 -15.0   205   28   14   7.1   3.9   39.1 102.3    12.9      M    M
 25000  -23.9 -11.0   205   25   13   8.9   4.4   38.2 100.8    12.3      M    M
 24000  -21.6  -6.9   205   21   11   8.4   4.6   37.5  99.5    11.9      M    M
 23000  -18.9  -2.0   210   22   11   9.0   4.9   37.2  99.0    11.7      M    M
 22000  -16.4   2.5   215   23   12   5.7   3.1   36.6  97.9    11.4      M    M
 21000  -15.3   4.5   220   24   12   2.4   1.3   34.5  94.1     9.8      M    M
 20000  -14.7   5.5   225   25   13   2.1   1.2   31.8  89.2     7.6      M    M
 19500  -14.4   6.1   225   24   12   1.3   0.7   30.3  86.6     6.4      M    M
 19000  -14.3   6.3   230   22   11   2.2   1.2   28.8  83.9     5.1      M    M
 18500  -13.1   8.4   230   21   11  14.1   7.7   28.8  83.8     4.9      M    M
 18000  -11.8  10.8   225   21   11   6.1   3.4   28.6  83.5     4.7      M    M
 17500  -10.9  12.4   225   20   11   9.2   5.1   28.1  82.6     4.2      M    M
 17000   -8.4  16.9   225   20   10  12.1   6.7   28.6  83.5     4.6      M    M
 16500   -6.9  19.6   220   19   10   7.8   4.3   28.8  83.8     4.6      M    M
 16000   -5.9  21.4   220   19   10   6.8   3.7   28.3  82.9     4.2      M    M
 15500   -4.9  23.2   220   18    9   6.8   3.7   27.7  81.9     3.7      M    M
 15000   -4.0  24.8   220   18    9   6.8   3.7   27.3  81.1     3.2      M    M
 14500   -3.0  26.6   220   17    9   6.8   3.7   26.8  80.2     2.8      M    M
 14000   -2.0  28.4   220   17    9   6.8   3.7   26.3  79.4     2.4      M    M
 13500   -1.0  30.2   220   14    7   6.8   3.7   25.8  78.5     1.8      M    M
 13000   -0.1  31.8   215   12    6   6.8   3.8   25.3  77.6     1.4      M    M
 12500    0.9  33.6   210   10    5   6.9   3.8   24.8  76.7     0.9      M    M
 12000    1.9  35.4   205    8    4   6.9   3.8   24.4  75.9     0.4      M    M
 11500    2.9  37.2   215    9    5   6.8   3.7   23.9  75.0    -0.1    517  2.6
 11000    3.9  39.0   225   10    5   7.6   4.2   23.5  74.3    -0.6    471  2.4
 10500    5.0  41.0   235   12    6   7.6   4.1   23.1  73.7    -0.9    424  2.2
 10250    5.5  41.9   235   12    6   7.4   4.1   23.0  73.3    -1.1    400  2.0
 10000    6.0  42.8   235   11    6   7.4   4.1   22.8  73.0    -1.3    377  1.9
  9750    6.6  43.9   240   11    6   7.4   4.1   22.6  72.7    -1.5    353  1.8
  9500    7.1  44.8   240   11    6   7.4   4.1   22.4  72.4    -1.7    329  1.7
  9250    7.7  45.9   245   10    5   7.4   4.1   22.3  72.1    -1.9    306  1.6
  9000    8.2  46.8   245   10    5   7.4   4.1   22.1  71.8    -2.0    282  1.4
  8750    8.7  47.7   240    9    5   7.4   4.1   21.9  71.4    -2.2    259  1.3
  8500    9.3  48.7   240    8    4   7.4   4.1   21.7  71.1    -2.4    235  1.2
  8250    9.8  49.6   235    6    3   7.4   4.1   21.5  70.8    -2.6    212  1.1
  8000   10.4  50.7   225    5    3   7.5   4.1   21.4  70.5    -2.8    188  1.0
  7750   10.9  51.6   205    5    3   7.4   4.0   21.2  70.1    -3.0    165  0.8
  7500   11.4  52.5   190    6    3   7.7   4.2   21.0  69.8    -3.2    141  0.7
  7250   12.0  53.6   175    7    4   6.6   3.6   20.8  69.5    -3.4    117  0.6
  7000   12.3  54.1   165    9    4   4.3   2.4   20.5  68.9    -3.8     99  0.5
  6750   12.5  54.5   160   10    5   3.7   2.0   20.0  68.0    -4.3     86  0.4
  6500   12.8  55.0   155   12    6   4.0   2.2   19.6  67.2    -4.8     72  0.4
  6250   13.0  55.4   155   13    7   3.7   2.0   19.1  66.4    -5.4     58  0.3
  6000   13.2  55.8   150   15    8   4.7   2.6   18.7  65.7    -5.9     44  0.2
  5750   13.6  56.5   150   13    7   5.7   3.1   18.4  65.1    -6.2     25  0.1
  5500   14.0  57.2   145   11    6   5.4   3.0   18.1  64.5    -6.6      6  0.0
  5250   14.4  57.9   135    9    5   5.7   3.1   17.7  63.9    -6.9      M    M
  5000   14.8  58.6   125    7    4   5.1   2.8   17.4  63.4    -7.3      M    M

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

           08/27/2014 at 0900 MDT          |       08/27/2014 at 1200 MDT
                                           |
K index... +24.1  LI... -3.4               | K index... +24.7  LI... -1.6
CAPE... +689.3  CIN... -1.5                | CAPE... +238.6  CIN... -2.0
                                           |
Height Temperature  Wnd WndSpd  Lapse Rate | Temperature  Wnd WndSpd  Lapse Rate
ft MSL deg C deg F  Dir kt m/s  C/km F/kft | deg C deg F  Dir kt m/s  C/km F/kft
--------------------------------------------------------------------------------
 50000 -59.5 -75.1  245  25 13   2.1   1.2 | -58.8 -73.8  235  21 11   2.8   1.5
 45000 -56.0 -68.8  230  40 21   2.9   1.6 | -54.5 -66.1  225  38 19   3.1   1.7
 40000 -51.5 -60.7  210  47 24   5.5   3.0 | -49.8 -57.6  210  51 26   4.7   2.6
 38000 -48.2 -54.8  210  54 28   5.5   3.0 | -46.8 -52.2  210  54 28   4.9   2.7
 36000 -44.9 -48.8  215  60 31   5.5   3.0 | -43.9 -47.0  215  57 29   4.9   2.7
 34000 -40.6 -41.1  210  60 31   6.8   3.7 | -41.2 -42.2  215  52 27   3.4   1.9
 32000 -36.5 -33.7  210  57 29   6.7   3.7 | -39.2 -38.6  215  43 22   3.4   1.9
 30000 -33.2 -27.8  205  49 25   5.0   2.8 | -35.7 -32.3  215  34 17   7.2   4.0
 29000 -31.7 -25.1  205  43 22   5.1   2.8 | -33.5 -28.3  215  29 15   7.3   4.0
 28000 -30.2 -22.4  200  38 19   5.0   2.7 | -31.3 -24.3  215  25 13   7.2   4.0
 27000 -28.4 -19.1  200  35 18   6.4   3.5 | -29.1 -20.4  220  23 12   7.8   4.3
 26000 -26.5 -15.7  200  32 17   6.5   3.5 | -26.8 -16.2  225  22 11   7.8   4.3
 25000 -24.6 -12.3  200  30 15   6.5   3.6 | -24.5 -12.1  230  21 11   7.8   4.3
 24000 -22.5  -8.5  200  28 14   7.5   4.1 | -22.2  -8.0  230  21 11   7.3   4.0
 23000 -20.3  -4.5  200  26 13   7.5   4.1 | -20.1  -4.2  230  20 10   7.3   4.0
 22000 -18.0  -0.4  195  24 12   7.6   4.2 | -17.9  -0.2  230  20 10   7.4   4.0
 21000 -16.0   3.2  200  23 12   6.8   3.7 | -15.9   3.4  230  20 10   6.6   3.6
 20000 -14.0   6.8  200  23 12   6.8   3.7 | -13.5   7.7  230  19 10   6.6   3.6
 19500 -12.5   9.5  205  22 11   6.9   3.8 | -12.6   9.3  230  19 10   6.7   3.7
 19000 -11.5  11.3  205  22 11   6.1   3.3 | -11.6  11.1  235  19 10   6.0   3.3
 18500 -10.7  12.7  210  22 11   6.1   3.4 | -10.7  12.7  235  18  9   6.0   3.3
 18000  -9.8  14.4  210  21 11   6.3   3.4 |  -9.9  14.2  235  18  9   6.0   3.3
 17500  -8.8  16.2  215  21 11   6.4   3.5 |  -9.0  15.8  235  18  9   5.9   3.2
 17000  -7.9  17.8  215  21 11   6.4   3.5 |  -8.1  17.4  235  18  9   5.9   3.3
 16500  -7.0  19.4  220  20 10   6.6   3.6 |  -7.3  18.9  240  18  9   5.8   3.2
 16000  -6.0  21.2  220  20 10   6.6   3.6 |  -6.4  20.5  240  18  9   5.8   3.2
 15500  -5.1  22.8  220  20 10   6.4   3.5 |  -5.6  21.9  240  18  9   6.0   3.3
 15000  -4.1  24.6  220  20 10   6.3   3.5 |  -4.7  23.5  240  18  9   6.1   3.3
 14500  -3.2  26.2  225  19 10   6.1   3.4 |  -3.8  25.2  240  18  9   6.1   3.3
 14000  -2.4  27.7  225  19 10   5.9   3.2 |  -2.9  26.8  240  18  9   6.0   3.3
 13500  -1.5  29.3  225  18  9   5.8   3.2 |  -2.0  28.4  240  18  9   6.1   3.4
 13000  -0.7  30.7  225  17  9   5.7   3.1 |  -1.1  30.0  240  18  9   6.3   3.5
 12500   0.1  32.2  225  16  8   5.9   3.2 |  -0.2  31.6  240  18  9   6.4   3.5
 12000   1.0  33.8  225  15  8   6.8   3.7 |   0.8  33.4  235  18  9   6.9   3.8
 11500   2.0  35.6  225  15  8   6.7   3.7 |   1.8  35.2  235  17  9   6.9   3.8
 11000   2.9  37.2  225  14  7   6.4   3.5 |   2.8  37.0  235  16  8   7.0   3.8
 10500   3.8  38.8  230  13  7   6.1   3.3 |   3.8  38.8  235  14  7   6.8   3.7
 10250   4.2  39.6  230  13  7   5.4   3.0 |   4.2  39.6  230  14  7   6.3   3.4
 10000   4.6  40.3  230  13  6   6.6   3.6 |   4.7  40.5  230  13  7   6.7   3.7
  9750   5.1  41.2  235  12  6   7.6   4.2 |   5.2  41.4  225  12  6   7.3   4.0
  9500   5.7  42.3  235  11  6   7.1   3.9 |   5.7  42.3  225  10  5   6.8   3.8
  9250   6.1  43.0  240  11  6   6.5   3.6 |   6.1  43.0  220   9  5   5.9   3.2
  9000   6.6  43.9  240  10  5   7.1   3.9 |   6.6  43.9  220   8  4   6.5   3.6
  8750   7.1  44.8  245  10  5   8.1   4.5 |   7.0  44.6  220   7  4   7.5   4.1
  8500   7.7  45.9  245   9  5   7.5   4.1 |   7.5  45.5  215   6  3   7.8   4.3
  8250   8.2  46.8  250   8  4   6.7   3.7 |   8.1  46.6  215   5  3   8.1   4.4
  8000   8.6  47.5  250   8  4   7.5   4.1 |   8.6  47.5  215   5  3   8.6   4.7
  7750   9.2  48.6  250   7  4   9.3   5.1 |   9.3  48.7  220   5  2  10.2   5.6
  7500   9.8  49.6  250   6  3   8.8   4.8 |  10.1  50.2  220   5  2  10.2   5.6
  7250  10.4  50.7  240   6  3   7.7   4.3 |  10.8  51.4  220   4  2   9.5   5.2
  7000  10.9  51.6  235   5  3   8.1   4.4 |  11.5  52.7  225   4  2   9.8   5.4
  6750  11.5  52.7  225   5  2   8.6   4.7 |  12.2  54.0  225   4  2  10.5   5.8
  6500  12.1  53.8  220   4  2   9.0   4.9 |  13.0  55.4  225   4  2  10.7   5.9
  6250  12.8  55.0  215   4  2   8.7   4.8 |  13.8  56.8  230   4  2  10.3   5.7
  6000  13.4  56.1  205   3  2   9.4   5.2 |  14.6  58.3  230   4  2  10.6   5.8
  5750  14.1  57.4  200   4  2  12.5   6.8 |  15.5  59.9  230   4  2  15.8   8.7
  5500  15.2  59.4  205   3  2  15.4   8.5 |  16.9  62.4  235   4  2  23.6  13.0
  5250     M     M    M   M  M     M     M |     M     M    M   M  M     M     M
  5000     M     M    M   M  M     M     M |     M     M    M   M  M     M     M

           08/27/2014 at 1500 MDT          |       08/27/2014 at 1800 MDT
                                           |
K index... +27.7  LI... -1.2               | K index... +28.0  LI... -1.3
CAPE... +156.3  CIN... -32.1               | CAPE... +196.5  CIN... -36.1
                                           |
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  210  11  6   2.8   1.6 | -58.4 -73.1  210  10  5   3.0   1.7
 45000 -54.2 -65.6  210  22 11   3.9   2.1 | -53.9 -65.0  215  13  7   2.8   1.5
 40000 -48.5 -55.3  215  40 21   2.3   1.3 | -49.8 -57.6  255  18  9   1.7   0.9
 38000 -47.3 -53.1  220  37 19   2.0   1.1 | -49.0 -56.2  300  20 10   1.3   0.7
 36000 -46.0 -50.8  225  33 17   2.0   1.1 | -48.1 -54.6  325  31 16   1.5   0.8
 34000 -43.5 -46.3  230  27 14   5.0   2.7 | -44.6 -48.3  325  33 17   7.4   4.1
 32000 -40.5 -40.9  235  21 11   5.0   2.8 | -40.2 -40.4  325  31 16   7.5   4.1
 30000 -36.0 -32.8  240  18  9   8.8   4.8 | -35.2 -31.4  315  26 13   8.8   4.8
 29000 -33.3 -27.9  245  18  9   8.8   4.9 | -32.5 -26.5  310  23 12   8.8   4.8
 28000 -30.7 -23.3  250  17  9   8.9   4.9 | -29.9 -21.8  300  21 11   8.8   4.8
 27000 -28.2 -18.8  255  17  9   8.1   4.5 | -27.5 -17.5  295  20 10   7.9   4.3
 26000 -25.8 -14.4  260  17  9   8.1   4.5 | -25.2 -13.4  290  20 10   7.9   4.3
 25000 -23.4 -10.1  260  16  8   8.2   4.5 | -22.8  -9.0  290  20 10   7.9   4.4
 24000 -21.2  -6.2  265  17  9   7.0   3.8 | -20.7  -5.3  285  20 10   6.8   3.8
 23000 -19.2  -2.6  265  17  9   7.0   3.8 | -18.7  -1.7  285  20 10   6.8   3.7
 22000 -17.1   1.2  265  18  9   7.0   3.9 | -16.7   1.9  280  20 11   6.9   3.8
 21000 -15.2   4.6  265  18  9   6.4   3.5 | -14.7   5.5  280  21 11   6.8   3.7
 20000 -12.8   9.0  265  18  9   6.4   3.5 | -12.2  10.0  275  21 11   6.8   3.7
 19500 -11.9  10.6  265  19 10   6.5   3.6 | -11.2  11.8  275  22 11   6.9   3.8
 19000 -11.0  12.2  265  19 10   6.2   3.4 | -10.3  13.5  275  22 11   5.9   3.2
 18500 -10.1  13.8  265  19 10   6.2   3.4 |  -9.4  15.1  275  22 11   6.0   3.3
 18000  -9.2  15.4  260  19 10   6.0   3.3 |  -8.6  16.5  275  22 11   5.8   3.2
 17500  -8.3  17.1  260  19 10   5.8   3.2 |  -7.8  18.0  275  21 11   5.6   3.1
 17000  -7.5  18.5  260  19 10   5.8   3.2 |  -7.0  19.4  270  21 11   5.6   3.1
 16500  -6.7  19.9  260  20 10   5.5   3.0 |  -6.1  21.0  270  21 11   5.6   3.1
 16000  -5.9  21.4  260  21 11   5.5   3.0 |  -5.3  22.5  270  21 11   5.6   3.1
 15500  -5.1  22.8  255  22 11   5.6   3.1 |  -4.5  23.9  270  21 11   5.8   3.2
 15000  -4.3  24.3  255  22 11   5.7   3.1 |  -3.7  25.3  270  21 11   5.9   3.2
 14500  -3.4  25.9  255  23 12   6.0   3.3 |  -2.8  27.0  270  22 11   6.2   3.4
 14000  -2.5  27.5  250  23 12   6.3   3.5 |  -1.9  28.6  265  22 11   6.6   3.6
 13500  -1.6  29.1  250  23 12   6.5   3.6 |  -0.9  30.4  265  22 12   6.8   3.7
 13000  -0.6  30.9  245  23 12   7.0   3.9 |   0.1  32.2  265  22 11   7.4   4.1
 12500   0.4  32.7  245  22 11   7.1   3.9 |   1.2  34.2  265  21 11   7.5   4.1
 12000   1.5  34.7  240  21 11   7.9   4.3 |   2.4  36.3  260  20 10   8.5   4.7
 11500   2.6  36.7  240  19 10   7.8   4.3 |   3.6  38.5  260  18 10   8.4   4.6
 11000   3.7  38.7  235  17  9   7.3   4.0 |   4.8  40.6  260  17  9   7.4   4.1
 10500   4.7  40.5  235  15  8   7.1   3.9 |   5.9  42.6  260  15  8   6.5   3.6
 10250   5.2  41.4  230  14  7   6.4   3.5 |   6.3  43.3  260  15  7   5.3   2.9
 10000   5.7  42.3  230  13  7   6.9   3.8 |   6.7  44.1  255  14  7   8.2   4.5
  9750   6.2  43.2  225  12  6   7.4   4.1 |   7.4  45.3  255  13  7  10.1   5.6
  9500   6.7  44.1  220  11  6   7.1   3.9 |   8.1  46.6  255  12  6   8.9   4.9
  9250   7.2  45.0  220  10  5   6.4   3.5 |   8.7  47.7  255  11  6   6.3   3.5
  9000   7.6  45.7  220   9  5   6.9   3.8 |   9.1  48.4  250  10  5   7.2   3.9
  8750   8.2  46.8  215   8  4   7.8   4.3 |   9.8  49.6  250   8  4   9.3   5.1
  8500   8.7  47.7  215   7  4   7.1   3.9 |  10.4  50.7  245   7  4   8.1   4.4
  8250   9.2  48.6  210   6  3   6.3   3.5 |  11.0  51.8  240   6  3   7.3   4.0
  8000   9.7  49.5  205   5  3   6.6   3.6 |  11.5  52.7  235   4  2   7.1   3.9
  7750  10.2  50.4  205   4  2   7.2   4.0 |  12.0  53.6  220   3  2   6.9   3.8
  7500  10.7  51.3  200   3  2   7.3   4.0 |  12.5  54.5  190   2  1   6.7   3.7
  7250  11.2  52.2  200   3  1   7.3   4.0 |  12.9  55.2  175   2  1   6.7   3.7
  7000  11.7  53.1  200   2  1   7.1   3.9 |  13.4  56.1  155   2  1   6.5   3.6
  6750  12.2  54.0  200   1  1   8.3   4.6 |  13.8  56.8  140   2  1   7.3   4.0
  6500  12.9  55.2  200   1  1   9.9   5.4 |  14.4  57.9  140   2  1   9.5   5.2
  6250  13.6  56.5  200   1  0   9.8   5.4 |  15.1  59.2  140   2  1   9.6   5.3
  6000  14.4  57.9  205   1  0  10.1   5.5 |  15.9  60.6  140   2  1  11.2   6.1
  5750  15.2  59.4  210   1  1  14.1   7.7 |  16.8  62.2  145   2  1  14.8   8.1
  5500  16.5  61.7  225   1  1  19.9  10.9 |  17.9  64.2  150   2  1  15.5   8.5
  5250     M     M    M   M  M     M     M |     M     M    M   M  M     M     M
  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.