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
000
UXUS97 KGJT 221341
SRGGJT

Soaring Forecast
National Weather Service Grand Junction, Colorado
0741 MDT Monday, May 22, 2017

This forecast is for Monday, May 22, 2017:

If the trigger temperature of 59.7 F/15.4 C is reached...then
   Thermal Soaring Index....................... Excellent
   Maximum rate of lift........................ 834 ft/min (4.2 m/s)
   Maximum height of thermals.................. 15464 ft MSL (10625 ft AGL)

Forecast maximum temperature................... 74.0 F/23.8 C
Time of trigger temperature.................... 0900 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................. 14033 ft MSL (9194 ft AGL)
Thermal soaring outlook for Tuesday 05/23...... Excellent

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

Remarks...

Sunrise/Sunset.................... 05:55:29 / 20:26:02 MDT
Total possible sunshine........... 14 hr 30 min 33 sec (870 min 33 sec)
Altitude of sun at 13:10:57 MDT... 71.40 degrees

Upper air data from rawinsonde observation taken on 05/22/2017 at 0600 MDT

Freezing level.................. 10316 ft MSL (5477 ft AGL)
Convective condensation level... 11475 ft MSL (6636 ft AGL)
Lifted condensation level....... 14013 ft MSL (9174 ft AGL)
Lifted index.................... -2.5
K index......................... +19.2

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  -57.6 -71.7   300   35   18  -4.9  -2.7  105.1 221.3    46.6      M    M
 45000  -57.4 -71.3   310   30   15  -4.0  -2.2   79.5 175.0    34.4      M    M
 40000  -58.7 -73.7   340   35   18  -9.8  -5.4   54.5 130.2    20.4      M    M
 38000  -58.4 -73.1   355   41   21   7.8   4.3   46.1 115.1    15.4      M    M
 36000  -55.3 -67.5   010   55   29   5.8   3.2   42.1 107.7    13.0      M    M
 34000  -50.6 -59.1   010   50   26   6.3   3.5   40.4 104.7    12.1      M    M
 32000  -45.9 -50.6   015   45   23   7.3   4.0   37.7  99.8    10.5      M    M
 30000  -41.7 -43.1   020   39   20   6.6   3.6   35.6  96.1     9.2      M    M
 29000  -39.8 -39.6   015   36   18   6.6   3.6   34.2  93.6     8.3      M    M
 28000  -37.8 -36.0   010   33   17   6.6   3.6   33.0  91.4     7.5      M    M
 27000  -35.6 -32.1   010   30   15   8.5   4.7   32.2  89.9     6.9      M    M
 26000  -33.0 -27.4   360   27   14   8.5   4.7   31.7  89.0     6.6      M    M
 25000  -30.5 -22.9   355   25   13   8.5   4.7   31.3  88.4     6.4      M    M
 24000  -27.9 -18.2   345   21   11   7.9   4.3   30.8  87.5     6.0      M    M
 23000  -25.7 -14.3   345   21   11   7.4   4.1   29.9  85.9     5.4      M    M
 22000  -23.4 -10.1   345   20   10   9.1   5.0   29.2  84.6     4.8      M    M
 21000  -20.7  -5.3   340   20   10   8.9   4.9   28.9  84.0     4.6      M    M
 20000  -18.0  -0.4   340   19   10   9.0   4.9   28.7  83.6     4.5      M    M
 19500  -16.8   1.8   340   20   10   7.4   4.0   28.5  83.2     4.3      M    M
 19000  -15.8   3.6   335   21   11   6.7   3.7   27.9  82.3     3.8      M    M
 18500  -14.6   5.7   335   21   11   7.9   4.3   27.5  81.6     3.5      M    M
 18000  -13.6   7.5   330   20   10   6.5   3.6   27.1  80.7     3.1      M    M
 17500  -12.0  10.4   330   22   11  10.5   5.8   26.4  79.5     2.5      M    M
 17000  -11.1  12.0   335   23   12   2.7   1.5   25.8  78.5     2.1      M    M
 16500  -10.4  13.3   335   24   12   5.3   2.9   24.8  76.7     1.2      M    M
 16000   -9.6  14.7   335   24   13   6.8   3.8   24.2  75.6     0.6      M    M
 15500   -8.8  16.2   350   22   11   4.3   2.4   23.5  74.4    -0.1    831  4.2
 15000   -8.0  17.6   360   20   10  -0.4  -0.2   22.9  73.2    -0.7    790  4.0
 14500   -8.6  16.5   015   20   10   4.4   2.4   20.6  69.1    -2.8    795  4.0
 14000   -7.4  18.7   030   21   11   8.2   4.5   20.4  68.7    -3.0    742  3.8
 13500   -6.1  21.0   025   19   10   8.4   4.6   20.2  68.3    -3.3    689  3.5
 13000   -4.8  23.4   025   17    9   7.3   4.0   20.0  68.0    -3.5    637  3.2
 12500   -4.0  24.8   020   15    8   4.5   2.5   19.4  66.8    -4.1    598  3.0
 12000   -3.9  25.0   015   13    7   4.0   2.2   18.1  64.5    -5.5    579  2.9
 11500   -2.7  27.1   020   12    6   8.3   4.6   17.8  64.0    -5.8    529  2.7
 11000   -1.7  28.9   020   11    6   7.0   3.8   17.4  63.3    -6.3    483  2.5
 10500   -0.5  31.1   025   10    5   8.9   4.9   17.1  62.7    -6.6    433  2.2
 10250    0.2  32.4   025   10    5   8.8   4.8   17.0  62.7    -6.6    405  2.1
 10000    0.8  33.4   020   11    5   7.4   4.1   16.9  62.4    -6.8    380  1.9
  9750    1.3  34.3   020   11    6   7.7   4.2   16.7  62.1    -7.0    356  1.8
  9500    1.9  35.4   020   12    6   7.7   4.2   16.6  61.8    -7.2    332  1.7
  9250    2.5  36.5   015   12    6   7.7   4.2   16.4  61.5    -7.3    307  1.6
  9000    3.0  37.4   015   13    7   7.7   4.2   16.3  61.3    -7.5    283  1.4
  8750    3.6  38.5   015   12    6   7.7   4.2   16.1  61.0    -7.7    259  1.3
  8500    4.1  39.4   015   11    6   7.7   4.2   15.9  60.7    -7.9    234  1.2
  8250    4.7  40.5   020   10    5   7.7   4.2   15.8  60.4    -8.1    210  1.1
  8000    5.3  41.5   020    9    5   7.7   4.2   15.6  60.2    -8.2    186  0.9
  7750    5.8  42.4   020    7    4   7.7   4.2   15.5  59.8    -8.4    161  0.8
  7500    6.4  43.5   020    5    3   7.7   4.2   15.3  59.5    -8.6    137  0.7
  7250    7.0  44.6   020    3    1   7.7   4.2   15.1  59.3    -8.8    113  0.6
  7000    7.5  45.5   000    0    0   7.7   4.2   15.0  59.0    -9.0     89  0.5
  6750    8.1  46.6   000    0    0   7.8   4.3   14.8  58.7    -9.2     64  0.3
  6500    8.7  47.7   310    1    0   7.4   4.0   14.7  58.4    -9.4     40  0.2
  6250    9.1  48.4   310    1    1   5.5   3.0   14.4  57.9    -9.7     18  0.1
  6000    9.5  49.1   310    2    1   4.6   2.5   14.0  57.3   -10.1      1  0.0
  5750    9.8  49.6   305    2    1   4.6   2.5   13.6  56.6   -10.5      M    M
  5500   10.2  50.4   290    1    1   5.6   3.1   13.3  55.9   -10.9      M    M
  5250   10.5  50.9   275    1    1   1.5   0.8   12.9  55.2   -11.3      M    M
  5000   10.2  50.4   250    1    1  -6.1  -3.4   12.0  53.5   -12.3      M    M

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

           05/22/2017 at 0900 MDT          |       05/22/2017 at 1200 MDT
                                           |
K index... +10.9  LI... +3.5               | K index... +1.9  LI... +1.6
CAPE... 0.0  CIN... -1.5                   | CAPE... +14.2  CIN... -5.0
                                           |
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 -57.5 -71.5  315  24 13   0.5   0.3 | -57.6 -71.7  320  27 14   0.3   0.1
 45000 -57.0 -70.6  325  34 17  -1.5  -0.8 | -57.5 -71.5  335  37 19  -1.5  -0.8
 40000 -59.3 -74.7  360  45 23  -1.4  -0.8 | -59.8 -75.6  355  48 25  -1.4  -0.8
 38000 -57.8 -72.0  005  48 25   4.3   2.3 | -58.1 -72.6  355  49 25   4.7   2.6
 36000 -55.2 -67.4  005  50 25   4.3   2.3 | -55.2 -67.4  355  49 25   4.7   2.6
 34000 -51.9 -61.4  005  49 25   8.1   4.4 | -51.5 -60.7  355  47 24   8.9   4.9
 32000 -46.4 -51.5  005  44 22   8.1   4.4 | -45.5 -49.9  350  42 22   8.9   4.9
 30000 -41.7 -43.1  360  39 20   7.8   4.3 | -40.5 -40.9  350  38 19   7.7   4.2
 29000 -39.4 -38.9  360  36 18   7.8   4.3 | -38.2 -36.8  345  35 18   7.7   4.2
 28000 -37.0 -34.6  355  33 17   7.8   4.3 | -35.9 -32.6  345  33 17   7.7   4.2
 27000 -34.6 -30.3  355  32 16   8.3   4.5 | -33.6 -28.5  340  32 16   7.5   4.1
 26000 -32.2 -26.0  350  31 16   8.2   4.5 | -31.4 -24.5  340  32 16   7.5   4.1
 25000 -29.7 -21.5  350  30 15   8.2   4.5 | -29.2 -20.6  335  31 16   7.5   4.1
 24000 -27.2 -17.0  350  29 15   8.3   4.6 | -26.9 -16.4  335  31 16   7.9   4.3
 23000 -24.8 -12.6  350  28 15   8.3   4.6 | -24.6 -12.3  335  30 16   7.8   4.3
 22000 -22.3  -8.1  355  27 14   8.3   4.6 | -22.2  -8.0  335  30 15   7.8   4.3
 21000 -19.8  -3.6  355  26 14   8.3   4.5 | -19.9  -3.8  335  29 15   7.7   4.2
 20000 -17.3   0.9  355  25 13   8.3   4.5 | -17.6   0.3  340  27 14   7.7   4.2
 19500 -16.1   3.0  360  25 13   8.3   4.6 | -16.5   2.3  340  27 14   7.7   4.2
 19000 -14.8   5.4  360  24 12   8.5   4.7 | -15.3   4.5  340  26 13   7.7   4.2
 18500 -13.4   7.9  355  23 12   5.8   3.2 | -13.6   7.5  345  25 13   7.3   4.0
 18000 -12.5   9.5  355  23 12   5.8   3.2 | -12.5   9.5  345  24 12   7.3   4.0
 17500 -11.8  10.8  350  22 12   4.2   2.3 | -11.5  11.3  350  23 12   6.3   3.4
 17000 -11.2  11.8  345  22 11   4.4   2.4 | -10.6  12.9  350  22 11   6.4   3.5
 16500 -10.5  13.1  345  22 11   4.9   2.7 |  -9.7  14.5  350  21 11   5.1   2.8
 16000  -9.8  14.4  345  21 11   5.1   2.8 |  -9.0  15.8  350  21 11   4.6   2.6
 15500  -9.0  15.8  345  21 11   5.1   2.8 |  -8.3  17.1  350  21 11   4.4   2.4
 15000  -8.3  17.1  345  20 10   5.1   2.8 |  -7.7  18.1  350  21 11   4.1   2.2
 14500  -7.6  18.3  350  19 10   5.2   2.8 |  -7.1  19.2  350  21 11   4.2   2.3
 14000  -6.8  19.8  355  18  9   5.6   3.1 |  -6.4  20.5  350  21 11   5.6   3.1
 13500  -6.1  21.0  360  17  9   5.6   3.1 |  -5.6  21.9  350  21 11   5.6   3.1
 13000  -5.2  22.6  005  16  8   7.2   3.9 |  -4.8  23.4  350  20 10   6.5   3.5
 12500  -4.2  24.4  005  16  8   7.0   3.8 |  -3.9  25.0  355  19 10   6.3   3.5
 12000  -3.1  26.4  010  15  8   7.9   4.3 |  -2.9  26.8  360  17  9   8.3   4.6
 11500  -1.9  28.6  010  14  7   7.9   4.3 |  -1.7  28.9  360  15  8   8.2   4.5
 11000  -0.8  30.6  015  13  7   7.5   4.1 |  -0.6  30.9  005  12  6   8.3   4.5
 10500   0.3  32.5  020  12  6   8.0   4.4 |   0.6  33.1  010  10  5   8.7   4.8
 10250   0.8  33.4  025  11  6   5.0   2.8 |   1.1  34.0  010   9  5   4.3   2.4
 10000   1.1  34.0  025  11  6   5.4   3.0 |   1.4  34.5  010   8  4   5.5   3.0
  9750   1.6  34.9  030  10  5   8.4   4.6 |   2.0  35.6  010   6  3  10.2   5.6
  9500   2.2  36.0  030  10  5   7.5   4.1 |   2.7  36.9  010   5  3   8.8   4.8
  9250   2.7  36.9  030  10  5   7.3   4.0 |   3.3  37.9  010   4  2   7.0   3.8
  9000   3.2  37.8  035   9  5   6.6   3.6 |   3.7  38.7  005   4  2   7.1   3.9
  8750   3.6  38.5  035   9  5   6.1   3.3 |   4.4  39.9  360   3  2   9.4   5.1
  8500   4.1  39.4  040   9  4   5.9   3.2 |   5.0  41.0  355   3  1   9.3   5.1
  8250   4.5  40.1  045   8  4   5.9   3.3 |   5.7  42.3  355   2  1   9.0   5.0
  8000   4.9  40.8  050   8  4   5.8   3.2 |   6.3  43.3  350   2  1   9.1   5.0
  7750   5.3  41.5  055   8  4   4.7   2.6 |   7.0  44.6  350   2  1   9.4   5.2
  7500   5.6  42.1  060   8  4   4.2   2.3 |   7.7  45.9  345   2  1   9.7   5.3
  7250   5.9  42.6  065   6  3   4.6   2.5 |   8.4  47.1  345   2  1   9.9   5.4
  7000   6.2  43.2  070   5  3   4.3   2.4 |   9.1  48.4  340   2  1   9.8   5.4
  6750   6.5  43.7  080   4  2   4.7   2.6 |   9.9  49.8  335   2  1  10.9   6.0
  6500   6.9  44.4  090   4  2   7.8   4.3 |  10.7  51.3  330   1  1  11.1   6.1
  6250   7.6  45.7  090   3  2   9.9   5.4 |  11.5  52.7  325   1  1  10.5   5.7
  6000   8.3  46.9  095   3  2   8.6   4.7 |  12.3  54.1  320   1  1  10.6   5.8
  5750   9.0  48.2  100   3  1  14.1   7.7 |  13.3  55.9  315   1  1  18.7  10.3
  5500  10.5  50.9  100   3  1  24.9  13.7 |  15.2  59.4  320   1  1  32.0  17.6
  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

           05/22/2017 at 1500 MDT          |       05/22/2017 at 1800 MDT
                                           |
K index... +15.6  LI... -0.0               | K index... +17.4  LI... -0.1
CAPE... +40.3  CIN... -1.9                 | CAPE... +10.6  CIN... -34.0
                                           |
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 -57.7 -71.9  325  29 15   0.1   0.1 | -57.9 -72.2  335  28 14  -0.0  -0.0
 45000 -57.8 -72.0  335  38 20  -2.1  -1.1 | -58.2 -72.8  340  40 21  -1.8  -1.0
 40000 -61.0 -77.8  350  54 28  -1.8  -1.0 | -60.9 -77.6  355  60 31  -1.6  -0.9
 38000 -58.7 -73.7  350  54 28   5.8   3.2 | -58.6 -73.5  350  60 31   5.8   3.2
 36000 -55.3 -67.5  350  52 27   5.8   3.2 | -55.1 -67.2  345  57 30   5.8   3.2
 34000 -51.0 -59.8  345  50 25   8.9   4.9 | -50.9 -59.6  345  57 29   8.8   4.8
 32000 -45.7 -50.3  345  47 24   8.8   4.9 | -45.7 -50.3  345  59 30   8.7   4.8
 30000 -40.6 -41.1  345  44 23   8.2   4.5 | -39.9 -39.8  350  57 29   8.5   4.7
 29000 -37.5 -35.5  340  41 21   8.3   4.5 | -37.3 -35.1  345  54 28   8.5   4.7
 28000 -35.0 -31.0  335  39 20   8.2   4.5 | -34.8 -30.6  345  52 27   8.5   4.7
 27000 -32.7 -26.9  335  38 19   7.2   4.0 | -32.3 -26.1  345  50 25   8.3   4.6
 26000 -30.6 -23.1  330  37 19   7.2   4.0 | -29.8 -21.6  345  48 25   8.3   4.6
 25000 -28.4 -19.1  330  36 19   7.2   4.0 | -27.3 -17.1  340  46 24   8.3   4.6
 24000 -26.3 -15.3  330  36 18   7.0   3.9 | -25.0 -13.0  335  45 23   6.5   3.5
 23000 -24.2 -11.6  330  35 18   7.0   3.9 | -23.0  -9.4  335  45 23   6.6   3.6
 22000 -22.1  -7.8  330  34 17   7.1   3.9 | -21.1  -6.0  335  44 23   6.6   3.6
 21000 -20.0  -4.0  330  33 17   7.3   4.0 | -19.2  -2.6  330  43 22   5.9   3.2
 20000 -17.8  -0.0  335  31 16   7.3   4.0 | -17.5   0.5  335  41 21   5.9   3.2
 19500 -16.7   1.9  335  31 16   7.3   4.0 | -16.6   2.1  335  39 20   5.9   3.3
 19000 -15.6   3.9  335  30 16   7.3   4.0 | -15.7   3.7  335  38 20   6.0   3.3
 18500 -14.5   5.9  340  29 15   7.2   4.0 | -14.8   5.4  335  37 19   6.6   3.6
 18000 -13.5   7.7  340  29 15   7.2   4.0 | -13.8   7.2  335  36 19   6.6   3.6
 17500 -12.4   9.7  340  28 14   7.3   4.0 | -12.8   9.0  335  35 18   6.8   3.8
 17000 -11.3  11.7  345  28 14   7.2   4.0 | -11.8  10.8  335  33 17   6.9   3.8
 16500 -10.2  13.6  345  27 14   7.0   3.8 | -10.8  12.6  340  32 17   7.1   3.9
 16000  -9.2  15.4  345  27 14   6.4   3.5 |  -9.7  14.5  340  30 16   7.6   4.2
 15500  -8.3  17.1  345  26 14   6.4   3.5 |  -8.5  16.7  340  28 15   7.6   4.2
 15000  -7.4  18.7  345  25 13   5.6   3.1 |  -7.4  18.7  340  26 14   7.8   4.3
 14500  -6.6  20.1  345  23 12   5.6   3.1 |  -6.3  20.7  340  24 12   7.7   4.3
 14000  -5.2  22.6  345  20 10   7.0   3.9 |  -4.5  23.9  335  21 11   8.3   4.5
 13500  -4.3  24.3  345  17  9   7.1   3.9 |  -3.3  26.1  335  20 10   8.3   4.6
 13000  -3.2  26.2  340  15  8   7.4   4.0 |  -2.1  28.2  335  18  9   8.5   4.6
 12500  -2.2  28.0  340  13  7   7.5   4.1 |  -0.9  30.4  330  17  9   8.5   4.7
 12000  -1.1  30.0  335  12  6   8.2   4.5 |   0.4  32.7  330  15  8   9.0   4.9
 11500   0.1  32.2  330  11  6   8.1   4.5 |   1.7  35.1  325  14  7   8.9   4.9
 11000   1.2  34.2  330  10  5   7.6   4.2 |   3.0  37.4  320  13  6   8.4   4.6
 10500   2.3  36.1  320   9  4   5.6   3.1 |   4.3  39.7  315  11  6   5.7   3.1
 10250   2.6  36.7  320   8  4   4.4   2.4 |   4.6  40.3  310  10  5   5.1   2.8
 10000   3.1  37.6  315   7  4   8.2   4.5 |   5.2  41.4  305  10  5   9.5   5.2
  9750   3.8  38.8  310   6  3   9.3   5.1 |   5.9  42.6  300   9  5   9.6   5.3
  9500   4.4  39.9  305   5  3   8.2   4.5 |   6.6  43.9  295   9  4   9.1   5.0
  9250   5.0  41.0  300   5  2   6.8   3.7 |   7.2  45.0  290   8  4   7.6   4.2
  9000   5.5  41.9  300   4  2   8.2   4.5 |   7.8  46.0  285   8  4   7.8   4.3
  8750   6.2  43.2  295   4  2   9.3   5.1 |   8.4  47.1  280   7  4   8.5   4.6
  8500   6.9  44.4  285   3  2   9.5   5.2 |   9.0  48.2  270   7  3   8.2   4.5
  8250   7.6  45.7  285   3  2  10.3   5.7 |   9.5  49.1  265   6  3   7.8   4.3
  8000   8.4  47.1  280   3  2  10.0   5.5 |  10.1  50.2  265   6  3   8.5   4.7
  7750   9.1  48.4  280   3  1   9.8   5.4 |  10.8  51.4  260   6  3   9.4   5.1
  7500   9.9  49.8  275   3  1   9.9   5.4 |  11.4  52.5  260   6  3   9.3   5.1
  7250  10.6  51.1  275   3  1   9.8   5.4 |  12.1  53.8  260   6  3   9.5   5.2
  7000  11.3  52.3  275   3  1  10.2   5.6 |  12.8  55.0  255   6  3   9.4   5.1
  6750  12.1  53.8  270   2  1  10.9   6.0 |  13.6  56.5  255   6  3   9.8   5.4
  6500  12.9  55.2  270   2  1  10.8   5.9 |  14.3  57.7  255   5  3  10.5   5.8
  6250  13.7  56.7  265   2  1  10.8   5.9 |  15.1  59.2  255   5  3  10.8   5.9
  6000  14.6  58.3  265   2  1  10.6   5.8 |  15.9  60.6  250   5  3  10.7   5.9
  5750  15.4  59.7  265   2  1  13.2   7.2 |  16.7  62.1  250   5  3  11.2   6.1
  5500  16.5  61.7  270   2  1  15.7   8.6 |  17.6  63.7  255   5  3  11.6   6.3
  5250  17.6  63.7  275   2  1  13.8   7.6 |  18.4  65.1  255   5  3  11.3   6.2
  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.