Soaring Guidance
Issued by NWS Grand Junction, CO

Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12
000
UXUS97 KGJT 291228
SRGGJT

Soaring Forecast
National Weather Service Grand Junction, Colorado
0628 MDT Thursday, June 29, 2017

This forecast is for Thursday, June 29, 2017:

If the trigger temperature of 81.7 F/27.6 C is reached...then
   Thermal Soaring Index....................... Excellent
   Maximum rate of lift........................ 1491 ft/min (7.6 m/s)
   Maximum height of thermals.................. 20669 ft MSL (15830 ft AGL)

Forecast maximum temperature................... 94.0 F/34.9 C
Time of trigger temperature.................... 1015 MDT
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................. 15943 ft MSL (11103 ft AGL)
Thermal soaring outlook for Friday 06/30....... Excellent

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

Remarks...

Sunrise/Sunset.................... 05:51:14 / 20:44:07 MDT
Total possible sunshine........... 14 hr 52 min 53 sec (892 min 53 sec)
Altitude of sun at 13:17:44 MDT... 74.03 degrees

Upper air data from rawinsonde observation taken on 06/29/2017 at 0600 MDT

Freezing level.................. 15021 ft MSL (10182 ft AGL)
Convective condensation level... 18291 ft MSL (13452 ft AGL)
Lifted condensation level....... 19466 ft MSL (14627 ft AGL)
Lifted index.................... -1.9
K index......................... +12.8

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  -63.7 -82.7   260   54   28   4.7   2.6   88.9 192.0    31.5      M    M
 45000  -54.4 -65.9   270   60   31   2.4   1.3   78.8 173.8    27.6      M    M
 40000  -49.6 -57.3   280   83   43   2.0   1.1   63.6 146.5    19.4      M    M
 38000  -48.9 -56.0   275   88   45   8.9   4.9   55.9 132.6    14.6      M    M
 36000  -46.1 -51.0   275   90   46   7.0   3.8   51.6 124.8    12.0      M    M
 34000  -43.0 -45.4   275   85   44   3.1   1.7   47.8 118.0     9.6      M    M
 32000  -40.1 -40.2   275   65   34   6.3   3.5   43.7 110.6     6.8      M    M
 30000  -35.4 -31.7   275   55   28   7.3   4.0   41.3 106.3     5.2      M    M
 29000  -33.1 -27.6   275   53   27   8.7   4.8   40.3 104.6     4.5      M    M
 28000  -30.4 -22.7   275   52   27   8.9   4.9   39.9 103.8     4.2      M    M
 27000  -27.7 -17.9   275   50   26   8.9   4.9   39.6 103.3     4.0      M    M
 26000  -25.1 -13.2   275   49   25   8.6   4.7   39.4 102.9     3.9      M    M
 25000  -22.9  -9.2   275   47   24   7.0   3.9   38.5 101.2     3.2      M    M
 24000  -21.0  -5.8   280   44   23   6.2   3.4   37.2  99.0     2.2      M    M
 23000  -18.6  -1.5   280   40   21   8.3   4.6   36.5  97.8     1.7      M    M
 22000  -16.1   3.0   280   37   19   8.3   4.5   36.0  96.8     1.3      M    M
 21000  -13.7   7.3   280   34   17   5.1   2.8   35.5  95.8     0.9      M    M
 20000  -12.7   9.1   280   30   16   6.0   3.3   33.2  91.7    -1.1   1453  7.4
 19500  -11.9  10.6   275   28   15   5.8   3.2   32.5  90.5    -1.8   1413  7.2
 19000  -10.7  12.7   270   27   14  10.2   5.6   32.3  90.1    -2.0   1362  6.9
 18500   -9.4  15.1   270   28   14   9.1   5.0   32.1  89.8    -2.2   1307  6.6
 18000   -8.0  17.6   270   28   15   9.0   4.9   31.9  89.4    -2.4   1253  6.4
 17500   -6.7  19.9   270   29   15   9.0   4.9   31.8  89.2    -2.6   1198  6.1
 17000   -5.4  22.3   270   30   15   9.0   4.9   31.7  89.0    -2.7   1144  5.8
 16500   -3.4  25.9   270   31   16   9.1   5.0   31.5  88.8    -2.9   1062  5.4
 16000   -2.1  28.2   270   31   16   8.2   4.5   31.4  88.5    -3.0   1009  5.1
 15500   -0.9  30.4   270   28   15   8.1   4.4   31.1  88.0    -3.3    959  4.9
 15000    0.3  32.5   270   26   13   8.1   4.4   30.8  87.5    -3.6    908  4.6
 14500    1.5  34.7   275   24   12   8.1   4.4   30.6  87.1    -3.9    858  4.4
 14000    2.6  36.7   275   22   11   8.1   4.5   30.4  86.6    -4.1    807  4.1
 13500    3.8  38.8   285   20   10   8.1   4.5   30.0  86.1    -4.5    757  3.8
 13000    5.0  41.0   290   19   10   8.1   4.5   29.8  85.6    -4.8    707  3.6
 12500    6.2  43.2   300   18    9   8.1   4.5   29.5  85.1    -5.1    656  3.3
 12000    7.4  45.3   310   18    9   8.0   4.4   29.3  84.7    -5.3    606  3.1
 11500    8.7  47.7   315   15    8   9.1   5.0   29.0  84.3    -5.6    553  2.8
 11000   10.0  50.0   315   13    7   9.0   5.0   28.9  84.1    -5.8    499  2.5
 10500   11.3  52.3   320   10    5   9.1   5.0   28.8  83.9    -5.9    444  2.3
 10250   12.0  53.6   325    9    5   8.9   4.9   28.8  83.8    -6.0    417  2.1
 10000   12.6  54.7   325    8    4   8.6   4.7   28.7  83.6    -6.1    390  2.0
  9750   13.3  55.9   330    8    4   8.7   4.8   28.6  83.5    -6.2    364  1.8
  9500   13.9  57.0   330    7    4   8.7   4.8   28.5  83.3    -6.3    337  1.7
  9250   14.5  58.1   330    7    3   8.7   4.8   28.4  83.2    -6.4    311  1.6
  9000   15.2  59.4   335    6    3   8.7   4.8   28.4  83.0    -6.5    284  1.4
  8750   15.8  60.4   330    6    3   8.7   4.8   28.3  82.9    -6.6    258  1.3
  8500   16.4  61.5   325    7    4   8.6   4.7   28.2  82.7    -6.7    231  1.2
  8250   17.1  62.8   325    7    4   9.1   5.0   28.1  82.5    -6.8    205  1.0
  8000   17.7  63.9   320    8    4   7.3   4.0   28.0  82.4    -6.9    178  0.9
  7750   18.1  64.6   335    8    4   3.5   1.9   27.6  81.8    -7.3    160  0.8
  7500   18.3  64.9   350    9    5   6.2   3.4   27.2  81.0    -7.8    145  0.7
  7250   19.0  66.2   360   11    6   9.3   5.1   27.1  80.8    -7.9    118  0.6
  7000   19.6  67.3   010   13    6   8.3   4.6   27.0  80.6    -8.0     92  0.5
  6750   20.3  68.5   015   12    6   9.3   5.1   26.9  80.5    -8.2     65  0.3
  6500   20.9  69.6   020   11    6   6.4   3.5   26.8  80.3    -8.3     38  0.2
  6250   21.2  70.2   025   10    5   2.6   1.4   26.4  79.5    -8.7     22  0.1
  6000   21.5  70.7   035    9    5   4.3   2.3   25.9  78.6    -9.2      7  0.0
  5750   21.9  71.4   040    8    4   8.5   4.7   25.6  78.1    -9.5      M    M
  5500   22.7  72.9   045    6    3  11.5   6.3   25.7  78.2    -9.5      M    M
  5250   23.4  74.1   060    4    2   4.8   2.6   25.6  78.2    -9.6      M    M
  5000   23.1  73.6   095    3    1 -16.3  -8.9   24.6  76.2   -10.6      M    M

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

           06/29/2017 at 0900 MDT          |       06/29/2017 at 1200 MDT
                                           |
K index... +13.4  LI... +1.7               | K index... +7.2  LI... +2.0
CAPE... 0.0  CIN... 0.0                    | CAPE... 0.0  CIN... 0.0
                                           |
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 -61.3 -78.3  270  45 23   3.3   1.8 | -60.8 -77.4  270  46 23   2.9   1.6
 45000 -56.1 -69.0  275  67 35   3.9   2.1 | -56.3 -69.3  275  70 36   3.5   1.9
 40000 -50.1 -58.2  280  86 44   3.4   1.9 | -50.7 -59.3  280  87 45   3.7   2.0
 38000 -48.0 -54.4  280  83 43   3.5   1.9 | -48.5 -55.3  280  83 43   3.7   2.0
 36000 -45.9 -50.6  280  80 41   3.5   1.9 | -46.3 -51.3  275  80 41   3.7   2.0
 34000 -43.1 -45.6  280  72 37   5.3   2.9 | -43.3 -45.9  280  72 37   5.7   3.2
 32000 -39.9 -39.8  280  60 31   5.3   2.9 | -39.8 -39.6  280  61 32   5.7   3.1
 30000 -35.6 -32.1  280  55 29   8.2   4.5 | -35.5 -31.9  280  57 29   8.2   4.5
 29000 -33.2 -27.8  280  55 28   8.2   4.5 | -32.4 -26.3  280  56 29   8.2   4.5
 28000 -30.7 -23.3  285  55 28   8.2   4.5 | -30.0 -22.0  285  55 28   8.2   4.5
 27000 -27.6 -17.7  285  54 28   8.4   4.6 | -27.5 -17.5  285  53 27   8.4   4.6
 26000 -25.1 -13.2  285  52 27   8.4   4.6 | -25.0 -13.0  285  51 26   8.4   4.6
 25000 -22.6  -8.7  285  51 26   8.5   4.6 | -22.5  -8.5  285  48 25   8.5   4.7
 24000 -20.3  -4.5  285  48 25   7.4   4.0 | -20.2  -4.4  285  46 24   7.4   4.0
 23000 -18.1  -0.6  280  46 23   7.4   4.0 | -17.9  -0.2  280  44 23   7.4   4.0
 22000 -15.9   3.4  275  43 22   7.6   4.1 | -15.7   3.7  280  42 22   7.4   4.1
 21000 -14.0   6.8  275  41 21   5.9   3.2 | -13.7   7.3  280  41 21   6.7   3.6
 20000 -12.3   9.9  270  39 20   5.9   3.2 | -11.7  10.9  275  39 20   6.7   3.7
 19500 -11.4  11.5  270  38 20   5.9   3.2 | -10.7  12.7  275  38 20   6.7   3.7
 19000 -10.5  13.1  265  37 19   6.9   3.8 |  -9.7  14.5  275  37 19   5.9   3.2
 18500  -9.4  15.1  265  37 19   7.3   4.0 |  -8.9  16.0  275  36 19   5.7   3.1
 18000  -8.3  17.1  265  37 19   7.4   4.1 |  -8.0  17.6  270  35 18   5.8   3.2
 17500  -7.2  19.0  270  37 19   8.4   4.6 |  -7.0  19.4  270  34 18   7.7   4.2
 17000  -6.0  21.2  270  36 18   8.4   4.6 |  -5.9  21.4  270  34 17   7.6   4.2
 16500  -4.8  23.4  270  35 18   8.2   4.5 |  -4.8  23.4  270  33 17   7.6   4.2
 16000  -3.6  25.5  270  33 17   8.2   4.5 |  -3.7  25.3  270  32 16   7.6   4.2
 15500  -2.4  27.7  275  31 16   8.0   4.4 |  -2.6  27.3  275  31 16   7.8   4.3
 15000  -1.3  29.7  275  29 15   7.7   4.2 |  -1.4  29.5  275  29 15   8.1   4.4
 14500  -0.1  31.8  280  28 14   7.7   4.2 |  -0.2  31.6  275  28 14   8.1   4.5
 14000   1.0  33.8  280  26 13   7.7   4.2 |   1.0  33.8  275  26 13   8.4   4.6
 13500   2.7  36.9  285  24 12   8.0   4.4 |   2.8  37.0  275  23 12   8.2   4.5
 13000   3.9  39.0  290  22 11   8.4   4.6 |   4.0  39.2  275  21 11   8.1   4.4
 12500   5.2  41.4  290  20 10   8.4   4.6 |   5.1  41.2  275  19 10   8.3   4.5
 12000   6.4  43.5  290  18  9   8.3   4.5 |   6.4  43.5  275  16  8   9.0   4.9
 11500   7.6  45.7  295  16  8   8.3   4.5 |   7.7  45.9  275  15  7   8.9   4.9
 11000   8.8  47.8  295  15  8   8.1   4.5 |   9.0  48.2  275  13  7   8.4   4.6
 10500  10.0  50.0  295  13  7   5.0   2.7 |  10.3  50.5  275  12  6   5.2   2.8
 10250  10.3  50.5  295  12  6   6.1   3.3 |  10.5  50.9  275  11  6   5.7   3.1
 10000  11.0  51.8  295  12  6  11.1   6.1 |  11.2  52.2  280  10  5  10.5   5.7
  9750  11.8  53.2  290  11  6  10.0   5.5 |  11.9  53.4  280  10  5   9.4   5.2
  9500  12.5  54.5  290  11  6   9.4   5.2 |  12.6  54.7  280   9  5   8.9   4.9
  9250  13.1  55.6  290  11  6   8.2   4.5 |  13.2  55.8  285   9  5   8.4   4.6
  9000  13.8  56.8  290  11  6   9.2   5.0 |  13.8  56.8  285   9  5   9.3   5.1
  8750  14.5  58.1  290  11  5  10.0   5.5 |  14.5  58.1  285   9  5   9.5   5.2
  8500  15.2  59.4  290  10  5   8.9   4.9 |  15.2  59.4  285   9  4   9.6   5.3
  8250  15.8  60.4  290  10  5   7.8   4.3 |  15.9  60.6  285   9  4   9.8   5.4
  8000  16.3  61.3  295   9  5   4.8   2.6 |  16.7  62.1  285   9  4  10.1   5.5
  7750  16.5  61.7  290   7  4   3.0   1.7 |  17.4  63.3  285   8  4  10.2   5.6
  7500  16.7  62.1  290   6  3   1.8   1.0 |  18.2  64.8  285   8  4  10.3   5.6
  7250  16.8  62.2  285   4  2  -0.7  -0.4 |  19.0  66.2  285   8  4  10.6   5.8
  7000  16.8  62.2  280   3  1   0.3   0.2 |  19.8  67.6  285   8  4   9.9   5.4
  6750  16.9  62.4  260   2  1   1.9   1.1 |  20.5  68.9  285   8  4   9.5   5.2
  6500  17.2  63.0  235   1  1   6.6   3.6 |  21.2  70.2  285   8  4  10.8   5.9
  6250  17.9  64.2  225   1  1   9.3   5.1 |  22.1  71.8  285   8  4  11.7   6.4
  6000  18.5  65.3  220   1  1   8.4   4.6 |  22.9  73.2  285   8  4  10.5   5.8
  5750  19.2  66.6  215   1  1  10.2   5.6 |  23.7  74.7  280   8  4  13.4   7.4
  5500  20.0  68.0  220   1  1  12.1   6.6 |  25.0  77.0  285   8  4  18.1   9.9
  5250  20.9  69.6  225   1  1  11.4   6.2 |  26.3  79.3  285   8  4  16.4   9.0
  5000     M     M    M   M  M     M     M |     M     M    M   M  M     M     M

           06/29/2017 at 1500 MDT          |       06/29/2017 at 1800 MDT
                                           |
K index... +11.4  LI... +1.9               | K index... +16.8  LI... +1.2
CAPE... 0.0  CIN... 0.0                    | CAPE... 0.0  CIN... 0.0
                                           |
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 -60.8 -77.4  270  49 25   3.0   1.6 | -60.5 -76.9  270  51 26   2.5   1.4
 45000 -56.4 -69.5  275  74 38   2.8   1.6 | -56.6 -69.9  280  75 39   2.3   1.2
 40000 -51.9 -61.4  280  88 45   3.9   2.2 | -53.1 -63.6  280  85 44   4.6   2.5
 38000 -49.6 -57.3  280  82 42   3.8   2.1 | -50.4 -58.7  280  78 40   4.4   2.4
 36000 -47.3 -53.1  280  76 39   3.9   2.1 | -47.8 -54.0  280  71 36   4.4   2.4
 34000 -43.9 -47.0  280  69 35   6.6   3.6 | -44.0 -47.2  280  64 33   7.2   3.9
 32000 -39.9 -39.8  280  61 31   6.6   3.6 | -39.7 -39.5  280  59 30   7.2   3.9
 30000 -35.3 -31.5  280  57 29   8.2   4.5 | -35.1 -31.2  280  54 28   8.0   4.4
 29000 -32.2 -26.0  280  55 28   8.2   4.5 | -32.1 -25.8  280  52 27   8.0   4.4
 28000 -29.8 -21.6  285  53 28   8.3   4.5 | -29.7 -21.5  280  50 26   8.1   4.4
 27000 -27.3 -17.1  280  51 26   8.3   4.6 | -27.3 -17.1  280  49 25   8.1   4.4
 26000 -24.8 -12.6  280  49 25   8.3   4.6 | -24.9 -12.8  280  47 24   8.1   4.5
 25000 -22.3  -8.1  280  46 24   8.4   4.6 | -22.5  -8.5  280  45 23   8.3   4.5
 24000 -20.0  -4.0  280  44 23   7.5   4.1 | -20.3  -4.5  280  43 22   7.0   3.8
 23000 -17.8  -0.0  280  42 21   7.5   4.1 | -18.2  -0.8  280  41 21   7.0   3.8
 22000 -15.5   4.1  280  39 20   7.5   4.1 | -16.1   3.0  280  39 20   7.0   3.8
 21000 -13.6   7.5  280  37 19   6.1   3.4 | -14.1   6.6  285  36 18   6.5   3.6
 20000 -11.8  10.8  280  34 18   6.2   3.4 | -12.2  10.0  285  31 16   6.6   3.6
 19500 -10.8  12.6  280  33 17   6.1   3.4 | -11.3  11.7  285  29 15   6.6   3.6
 19000  -9.9  14.2  280  31 16   6.8   3.7 | -10.2  13.6  285  27 14   7.8   4.3
 18500  -8.9  16.0  280  29 15   7.0   3.8 |  -9.1  15.6  280  25 13   8.2   4.5
 18000  -7.9  17.8  280  27 14   7.2   3.9 |  -7.9  17.8  280  24 12   8.3   4.5
 17500  -6.7  19.9  275  25 13   8.1   4.5 |  -6.7  19.9  280  22 11   8.5   4.7
 17000  -5.5  22.1  275  24 12   8.1   4.4 |  -5.5  22.1  275  21 11   8.5   4.7
 16500  -4.4  24.1  270  22 11   8.2   4.5 |  -4.2  24.4  275  20 10   8.8   4.8
 16000  -3.2  26.2  270  21 11   8.2   4.5 |  -2.9  26.8  270  19 10   8.8   4.8
 15500  -1.9  28.6  265  20 10   8.4   4.6 |  -1.6  29.1  270  18  9   9.0   4.9
 15000  -0.7  30.7  265  19 10   8.7   4.8 |  -0.2  31.6  270  18  9   9.2   5.0
 14500   0.6  33.1  265  18  9   8.7   4.8 |   1.2  34.2  270  17  9   9.2   5.0
 14000   2.5  36.5  265  17  9   8.8   4.8 |   3.2  37.8  270  16  8   9.0   5.0
 13500   3.9  39.0  265  16  8   8.6   4.7 |   4.6  40.3  270  16  8   8.9   4.9
 13000   5.1  41.2  265  16  8   8.3   4.6 |   5.9  42.6  270  15  8   8.8   4.8
 12500   6.3  43.3  270  15  8   8.5   4.6 |   7.2  45.0  270  15  8   8.8   4.8
 12000   7.6  45.7  270  14  7   8.8   4.8 |   8.5  47.3  275  14  7   8.8   4.8
 11500   8.9  48.0  270  13  7   8.6   4.7 |   9.8  49.6  275  14  7   8.6   4.7
 11000  10.1  50.2  275  12  6   7.7   4.2 |  11.0  51.8  280  13  7   7.8   4.3
 10500  11.2  52.2  275  11  6  10.2   5.6 |  12.1  53.8  280  13  6  11.3   6.2
 10250  12.1  53.8  280  11  5  11.0   6.0 |  13.1  55.6  280  12  6  11.6   6.4
 10000  12.7  54.9  280  10  5   8.2   4.5 |  13.7  56.7  285  12  6   7.2   3.9
  9750  13.4  56.1  280  10  5   9.1   5.0 |  14.3  57.7  285  11  6   8.3   4.6
  9500  14.0  57.2  280   9  5   8.4   4.6 |  14.9  58.8  285  11  5   8.1   4.5
  9250  14.6  58.3  285   9  5   8.7   4.8 |  15.5  59.9  290  10  5   8.9   4.9
  9000  15.3  59.5  285   9  5   9.9   5.4 |  16.2  61.2  290  10  5   9.3   5.1
  8750  16.0  60.8  285   9  5   9.6   5.3 |  16.9  62.4  290   9  5   9.2   5.0
  8500  16.8  62.2  285   9  5  10.5   5.8 |  17.6  63.7  290   9  5   9.5   5.2
  8250  17.6  63.7  285   9  5  11.6   6.4 |  18.3  64.9  290   9  4   9.9   5.4
  8000  18.4  65.1  285   9  5  10.3   5.6 |  19.1  66.4  290   9  4   9.6   5.3
  7750  19.2  66.6  285   9  5   9.2   5.0 |  19.8  67.6  290   9  4   9.2   5.0
  7500  19.9  67.8  285   9  4   9.9   5.5 |  20.5  68.9  290   9  4   9.9   5.5
  7250  20.6  69.1  285   9  4  10.4   5.7 |  21.2  70.2  290   8  4  10.9   6.0
  7000  21.4  70.5  285   9  4  10.2   5.6 |  22.0  71.6  290   8  4  10.0   5.5
  6750  22.2  72.0  280   9  4  10.3   5.7 |  22.8  73.0  290   8  4   9.3   5.1
  6500  22.9  73.2  280   8  4  10.7   5.9 |  23.5  74.3  290   8  4  10.4   5.7
  6250  23.8  74.8  280   8  4  11.3   6.2 |  24.3  75.7  290   8  4  11.6   6.4
  6000  24.6  76.3  280   8  4  10.0   5.5 |  25.2  77.4  290   8  4   9.9   5.4
  5750  25.4  77.7  280   8  4  13.0   7.1 |  25.9  78.6  290   8  4   9.8   5.4
  5500  26.6  79.9  280   8  4  18.6  10.2 |  26.7  80.1  290   8  4  12.6   6.9
  5250  28.0  82.4  285   8  4  17.3   9.5 |  27.6  81.7  290   7  4  12.9   7.1
  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 00.001 sec
                   West Longitude: 108 deg 31 min 59.998 sec
                   Elevation: 4839 feet (1475 meters)

and may not be representative of other areas along the Western Slope of
Colorado.  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.