Soaring Guidance
Issued by NWS Grand Junction, CO

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000
UXUS97 KGJT 171256
SRGGJT

Soaring Forecast
National Weather Service Grand Junction, Colorado
0556 MST Wednesday, January 17, 2018

This forecast is for Wednesday, January 17, 2018:

If the trigger temperature of 47.7 F/8.7 C is reached...then
   Thermal Soaring Index....................... Fair
   Maximum rate of lift........................ 219 ft/min (1.1 m/s)
   Maximum height of thermals.................. 8090 ft MSL (3251 ft AGL)

Forecast maximum temperature................... 45.0 F/7.7 C
Time of trigger temperature.................... None
Time of overdevelopment........................ None
Middle/high clouds during soaring window....... None
Surface winds during soaring window............ 20 mph or less
Height of the -3 thermal index................. 7352 ft MSL (2513 ft AGL)
Thermal soaring outlook for Thursday 01/18..... Fair

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

Remarks...

Sunrise/Sunset.................... 07:30:43 / 17:17:00 MST
Total possible sunshine........... 9 hr 46 min 17 sec (586 min 17 sec)
Altitude of sun at 12:24:14 MST... 30.31 degrees

Upper air data from rawinsonde observation taken on 01/17/2018 at 0500 MST

Freezing level.................. Entire airmass below 32 F / 0 C
Convective condensation level... 18794 ft MSL (13955 ft AGL)
Lifted condensation level....... 13268 ft MSL (8428 ft AGL)
Lifted index.................... +12.8
K index......................... -33.7

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  -61.5 -78.7   340   25   13   1.2   0.6  102.3 216.2    53.6      M    M
 45000  -60.1 -76.2   325   34   17   4.6   2.5   78.3 173.0    43.1      M    M
 40000  -61.0 -77.8   280   13    7  -3.4  -1.9   53.7 128.6    30.2      M    M
 38000  -60.9 -77.6   270   10    5   4.3   2.4   44.8 112.6    25.1      M    M
 36000  -59.1 -74.4   190   14    7   2.4   1.3   38.8 101.9    21.7      M    M
 34000  -57.1 -70.8   180   17    9   7.6   4.2   33.3  92.0    18.4      M    M
 32000  -51.7 -61.1   190   14    7   8.6   4.7   31.8  89.2    17.8      M    M
 30000  -46.5 -51.7   210   15    8   7.8   4.3   30.9  87.7    17.7      M    M
 29000  -44.4 -47.9   205   10    5   6.8   3.7   29.8  85.7    17.1      M    M
 28000  -42.0 -43.6   225   11    6   8.4   4.6   29.1  84.3    16.7      M    M
 27000  -39.4 -38.9   240   13    7   9.2   5.0   28.8  83.8    16.7      M    M
 26000  -36.8 -34.2   250   13    7   8.1   4.5   28.3  82.9    16.5      M    M
 25000  -34.4 -29.9   260   13    7   8.1   4.5   27.7  81.8    16.2      M    M
 24000  -31.8 -25.2   270    9    5   8.8   4.8   27.3  81.1    16.0      M    M
 23000  -29.2 -20.6   255   11    6   8.6   4.7   26.9  80.3    15.9      M    M
 22000  -26.8 -16.2   275   11    6   7.3   4.0   26.3  79.4    15.6      M    M
 21000  -24.9 -12.8   270   13    7   6.0   3.3   25.0  77.1    14.8      M    M
 20000  -23.0  -9.4   245   11    6   6.7   3.7   23.9  75.0    13.9      M    M
 19500  -22.0  -7.6   255    8    4   6.7   3.7   23.4  74.1    13.5      M    M
 19000  -21.0  -5.8   280    6    3   6.3   3.4   22.8  73.1    13.1      M    M
 18500  -19.8  -3.6   290    7    3   9.3   5.1   22.5  72.6    12.9      M    M
 18000  -18.4  -1.1   290    9    4   9.7   5.3   22.4  72.4    12.9      M    M
 17500  -17.0   1.4   290   10    5   5.6   3.1   22.3  72.2    13.0      M    M
 17000  -15.5   4.1   295   13    7   8.2   4.5   21.5  70.7    12.4      M    M
 16500  -14.3   6.3   305   13    7   8.3   4.6   21.3  70.3    12.3      M    M
 16000  -13.0   8.6   315   14    7   8.3   4.6   21.0  69.8    12.1      M    M
 15500  -11.8  10.8   310   15    8   8.5   4.7   20.8  69.4    12.0      M    M
 15000  -10.7  12.7   310   15    8   5.5   3.0   20.4  68.6    11.7      M    M
 14500   -9.9  14.2   320   17    9   5.0   2.7   19.6  67.2    11.0      M    M
 14000   -9.4  15.1   325   18    9   5.0   2.7   18.7  65.6    10.2      M    M
 13500   -8.5  16.7   330   19   10   7.2   4.0   18.1  64.5     9.6      M    M
 13000   -7.5  18.5   335   20   10   5.9   3.3   17.7  63.8     9.3      M    M
 12500   -6.6  20.1   330   16    8   6.5   3.5   17.0  62.5     8.7      M    M
 12000   -5.4  22.3   325   12    6   6.7   3.7   16.5  61.7     8.5      M    M
 11500   -4.2  24.4   330    7    4   4.5   2.4   16.1  61.0     8.3      M    M
 11000   -4.1  24.6   355    3    2  -2.4  -1.3   14.7  58.4     7.0      M    M
 10500   -3.9  25.0   055    5    2   9.6   5.3   13.6  56.4     5.8      M    M
 10250   -3.3  26.1   065    6    3   4.8   2.6   13.4  56.1     5.6      M    M
 10000   -3.1  26.4   060    4    2  -3.5  -1.9   12.7  54.8     5.1      M    M
  9750   -3.5  25.7   055    3    1  -0.7  -0.4   11.6  52.8     4.0      M    M
  9500   -3.3  26.1   020    1    1  -4.7  -2.6   10.9  51.6     3.4      M    M
  9250   -4.1  24.6   295    1    1  -4.3  -2.4    9.4  49.0     2.0      M    M
  9000   -3.8  25.2   270    3    1   8.3   4.5    9.0  48.1     1.5      M    M
  8750   -3.2  26.2   235    2    1   8.6   4.7    8.9  48.0     1.4      M    M
  8500   -2.7  27.1   185    2    1   3.9   2.2    8.7  47.6     1.2      M    M
  8250   -2.6  27.3   160    4    2   0.4   0.2    8.0  46.4     0.5      M    M
  8000   -2.6  27.3   150    6    3   1.7   0.9    7.3  45.2    -0.1    216  1.1
  7750   -2.6  27.3   145    6    3  -2.4  -1.3    6.6  43.9    -0.9    209  1.1
  7500   -3.0  26.6   135    6    3  -8.5  -4.7    5.4  41.7    -2.1    215  1.1
  7250   -3.5  25.7   130    6    3   1.0   0.6    4.2  39.5    -3.3    222  1.1
  7000   -2.9  26.8   120    6    3  10.5   5.8    4.0  39.3    -3.4    196  1.0
  6750   -2.2  28.0   110    5    3   7.2   4.0    4.0  39.1    -3.5    169  0.9
  6500   -1.8  28.8   100    4    2   3.9   2.1    3.6  38.6    -3.8    149  0.8
  6250   -1.6  29.1   080    4    2   2.5   1.4    3.1  37.6    -4.3    135  0.7
  6000   -1.4  29.5   060    4    2   3.0   1.7    2.6  36.7    -4.8    121  0.6
  5750   -1.1  30.0   070    3    2   2.3   1.3    2.1  35.7    -5.4    108  0.5
  5500   -0.9  30.4   100    3    2   4.6   2.5    1.6  34.8    -5.9     94  0.5
  5250   -1.1  30.0   125    4    2 -18.6 -10.2    0.7  33.2    -6.8     91  0.5
  5000   -4.0  24.8   135    3    1 -54.5 -29.9   -3.0  26.6   -10.5    173  0.9

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

           01/17/2018 at 0800 MST          |       01/17/2018 at 1100 MST
                                           |
K index... +12.1  LI... +4.8               | K index... +12.3  LI... +4.3
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 -61.6 -78.9  340  27 14   0.2   0.1 | -62.0 -79.6  345  27 14   0.5   0.3
 45000 -61.4 -78.5  335  30 16   0.3   0.2 | -61.3 -78.3  345  29 15   0.6   0.3
 40000 -59.5 -75.1  330  17  9   1.3   0.7 | -59.6 -75.3  345  22 11   1.2   0.6
 38000 -58.6 -73.5  310   9  4   1.8   1.0 | -58.5 -73.3  340  14  7   2.5   1.4
 36000 -57.5 -71.5  195   9  5   1.8   1.0 | -57.0 -70.6  245   4  2   2.5   1.4
 34000 -56.1 -69.0  180  21 11   7.1   3.9 | -54.8 -66.6  190  15  8   6.4   3.5
 32000 -51.3 -60.3  185  18  9   7.1   3.9 | -50.9 -59.6  185  15  8   6.4   3.5
 30000 -46.9 -52.4  190  15  8   7.9   4.3 | -46.8 -52.2  180  14  7   7.6   4.2
 29000 -44.6 -48.3  195  13  7   7.9   4.4 | -44.5 -48.1  185  11  6   7.7   4.2
 28000 -42.2 -44.0  200  12  6   7.9   4.4 | -42.3 -44.1  190   9  4   7.7   4.2
 27000 -39.8 -39.6  210  10  5   8.3   4.5 | -39.9 -39.8  195   6  3   8.3   4.6
 26000 -37.3 -35.1  220   8  4   8.4   4.6 | -37.4 -35.3  200   4  2   8.6   4.7
 25000 -34.8 -30.6  230   7  4   8.4   4.6 | -34.8 -30.6  215   2  1   8.6   4.7
 24000 -32.3 -26.1  250   6  3   8.1   4.5 | -32.3 -26.1  280   1  1   8.2   4.5
 23000 -30.0 -22.0  260   5  3   7.7   4.2 | -29.9 -21.8  345   1  1   7.9   4.3
 22000 -27.7 -17.9  280   4  2   7.7   4.2 | -27.6 -17.7  010   3  1   7.9   4.3
 21000 -25.4 -13.7  300   4  2   7.6   4.2 | -25.2 -13.4  015   4  2   7.6   4.2
 20000 -23.2  -9.8  310   5  2   7.6   4.1 | -22.4  -8.3  015   5  3   7.7   4.2
 19500 -22.1  -7.8  315   5  3   7.6   4.2 | -21.2  -6.2  015   6  3   7.7   4.2
 19000 -20.9  -5.6  320   5  3   7.6   4.2 | -20.1  -4.2  015   6  3   7.6   4.2
 18500 -19.3  -2.7  330   6  3   7.1   3.9 | -19.0  -2.2  015   6  3   7.5   4.1
 18000 -18.3  -0.9  330   6  3   7.1   3.9 | -17.9  -0.2  010   6  3   7.6   4.2
 17500 -17.2   1.0  335   6  3   7.0   3.8 | -16.8   1.8  010   7  3   7.2   3.9
 17000 -16.2   2.8  340   7  3   7.0   3.8 | -15.7   3.7  010   7  4   7.1   3.9
 16500 -15.2   4.6  340   7  4   6.9   3.8 | -14.7   5.5  010   7  4   7.3   4.0
 16000 -14.2   6.4  340   8  4   6.7   3.7 | -13.6   7.5  010   7  4   7.4   4.0
 15500 -13.2   8.2  340   8  4   6.7   3.7 | -12.5   9.5  010   8  4   7.2   3.9
 15000 -12.3   9.9  340   8  4   5.8   3.2 | -11.6  11.1  010   8  4   6.0   3.3
 14500 -11.5  11.3  335   9  5   5.9   3.2 | -10.7  12.7  010   8  4   6.1   3.3
 14000 -10.6  12.9  335   9  5   5.7   3.1 |  -9.8  14.4  010   8  4   5.8   3.2
 13500  -9.8  14.4  335  10  5   5.7   3.1 |  -8.9  16.0  015   8  4   5.9   3.2
 13000  -8.9  16.0  335  10  5   5.8   3.2 |  -8.1  17.4  015   8  4   5.3   2.9
 12500  -8.1  17.4  335  10  5   5.9   3.2 |  -7.3  18.9  015   8  4   5.4   3.0
 12000  -7.2  19.0  335  10  5   5.4   3.0 |  -6.5  20.3  020   8  4   5.2   2.8
 11500  -6.4  20.5  335  10  5   5.5   3.0 |  -5.7  21.7  025   8  4   5.3   2.9
 11000  -5.6  21.9  335   9  5   3.9   2.2 |  -5.0  23.0  030   8  4   4.1   2.3
 10500  -5.0  23.0  335   8  4   4.2   2.3 |  -4.4  24.1  030   8  4   4.3   2.3
 10250  -4.7  23.5  335   8  4   2.7   1.5 |  -4.1  24.6  030   8  4   3.6   2.0
 10000  -4.6  23.7  335   8  4   1.6   0.9 |  -3.8  25.2  030   8  4   3.0   1.7
  9750  -4.4  24.1  335   7  4   3.5   1.9 |  -3.6  25.5  035   8  4   3.5   1.9
  9500  -4.1  24.6  330   7  3   4.2   2.3 |  -3.3  26.1  035   8  4   3.5   1.9
  9250  -3.8  25.2  330   6  3   3.4   1.9 |  -3.1  26.4  035   8  4   2.8   1.6
  9000  -3.5  25.7  330   6  3   3.0   1.7 |  -2.8  27.0  040   7  4   2.3   1.3
  8750  -3.3  26.1  330   5  3   3.4   1.9 |  -2.6  27.3  040   7  4   3.3   1.8
  8500  -3.0  26.6  330   4  2   3.5   1.9 |  -2.3  27.9  045   6  3   3.0   1.6
  8250  -2.8  27.0  335   3  2   3.1   1.7 |  -2.2  28.0  050   6  3   1.9   1.0
  8000  -2.5  27.5  335   2  1   3.0   1.7 |  -2.0  28.4  055   5  3   1.6   0.9
  7750  -2.3  27.9  340   1  1   3.2   1.8 |  -1.9  28.6  060   5  3   2.7   1.5
  7500  -2.1  28.2  005   1  0   2.9   1.6 |  -1.6  29.1  065   5  2   3.1   1.7
  7250  -1.9  28.6  075   1  0   2.4   1.3 |  -1.5  29.3  070   4  2   2.3   1.3
  7000  -1.7  28.9  095   2  1   2.7   1.5 |  -1.3  29.7  080   4  2   2.6   1.4
  6750  -1.5  29.3  100   2  1   2.1   1.1 |  -1.1  30.0  085   4  2   2.3   1.3
  6500  -1.5  29.3  095   3  2  -1.0  -0.5 |  -0.9  30.4  085   3  2   2.8   1.5
  6250  -1.6  29.1  090   4  2  -1.9  -1.0 |  -0.7  30.7  085   3  1   2.2   1.2
  6000  -1.8  28.8  085   5  3  -3.5  -1.9 |  -0.5  31.1  090   2  1   5.2   2.9
  5750  -2.3  27.9  085   6  3 -11.6  -6.3 |   0.2  32.4  095   2  1  13.1   7.2
  5500  -3.5  25.7  080   5  3 -18.8 -10.3 |   1.4  34.5  095   2  1  17.0   9.3
  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

           01/17/2018 at 1400 MST          |       01/17/2018 at 1700 MST
                                           |
K index... +6.5  LI... +5.8                | K index... +8.9  LI... +4.2
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 -61.8 -79.2  350  25 13   0.4   0.2 | -62.0 -79.6  350  28 14   0.2   0.1
 45000 -61.2 -78.2  350  31 16   0.5   0.3 | -61.7 -79.1  355  32 17   0.1   0.0
 40000 -60.2 -76.4  350  33 17   0.7   0.4 | -62.3 -80.1  005  53 27  -0.4  -0.2
 38000 -59.0 -74.2  350  30 15   3.7   2.0 | -60.7 -77.3  010  60 31   5.7   3.2
 36000 -56.5 -69.7  340  21 11   3.7   2.0 | -56.8 -70.2  005  66 34   5.8   3.2
 34000 -53.9 -65.0  325  13  7   6.2   3.4 | -53.2 -63.8  005  64 33   6.7   3.7
 32000 -50.2 -58.4  270   7  4   6.3   3.4 | -49.2 -56.6  360  47 24   6.8   3.7
 30000 -46.2 -51.2  225   9  4   7.6   4.2 | -45.0 -49.0  355  32 17   7.3   4.0
 29000 -43.9 -47.0  230   6  3   7.7   4.2 | -42.8 -45.0  350  28 14   7.4   4.0
 28000 -41.6 -42.9  245   4  2   7.7   4.2 | -40.6 -41.1  350  23 12   7.4   4.0
 27000 -39.3 -38.7  280   3  2   8.0   4.4 | -38.4 -37.1  345  19 10   7.7   4.2
 26000 -36.8 -34.2  310   3  2   8.2   4.5 | -36.0 -32.8  345  18  9   7.8   4.3
 25000 -34.4 -29.9  330   4  2   8.2   4.5 | -33.7 -28.7  340  16  8   7.8   4.3
 24000 -31.9 -25.4  345   5  3   8.2   4.5 | -31.3 -24.3  340  15  8   7.9   4.4
 23000 -29.5 -21.1  355   5  3   8.2   4.5 | -28.9 -20.0  340  13  7   8.0   4.4
 22000 -27.0 -16.6  005   5  3   8.2   4.5 | -26.5 -15.7  345  12  6   8.1   4.4
 21000 -24.6 -12.3  010   6  3   7.7   4.2 | -24.2 -11.6  345  11  6   7.6   4.2
 20000 -21.8  -7.2  015   6  3   7.7   4.2 | -21.3  -6.3  345  11  6   7.6   4.2
 19500 -20.6  -5.1  015   6  3   7.7   4.2 | -20.2  -4.4  345  11  6   7.6   4.2
 19000 -19.5  -3.1  020   6  3   7.7   4.2 | -19.1  -2.4  345  11  6   7.6   4.2
 18500 -18.4  -1.1  020   6  3   7.2   3.9 | -18.0  -0.4  345  11  6   7.5   4.1
 18000 -17.3   0.9  020   6  3   7.2   4.0 | -16.9   1.6  345  11  6   7.5   4.1
 17500 -16.2   2.8  020   6  3   7.3   4.0 | -15.7   3.7  345  11  6   8.0   4.4
 17000 -15.2   4.6  020   6  3   7.3   4.0 | -14.5   5.9  350  11  6   8.0   4.4
 16500 -14.1   6.6  020   6  3   7.1   3.9 | -13.3   8.1  350  11  6   7.4   4.1
 16000 -13.0   8.6  020   5  3   6.9   3.8 | -12.3   9.9  350  11  5   6.8   3.7
 15500 -12.0  10.4  025   5  3   6.8   3.7 | -11.3  11.7  355  10  5   6.7   3.7
 15000 -11.0  12.2  030   5  3   6.2   3.4 | -10.4  13.3  355  10  5   6.4   3.5
 14500 -10.1  13.8  030   6  3   6.2   3.4 |  -9.4  15.1  360   9  5   6.4   3.5
 14000  -9.2  15.4  035   6  3   6.2   3.4 |  -8.4  16.9  005   8  4   7.0   3.9
 13500  -8.3  17.1  035   6  3   6.3   3.4 |  -7.4  18.7  005   8  4   7.1   3.9
 13000  -7.4  18.7  035   7  3   5.4   2.9 |  -6.4  20.5  010   8  4   6.1   3.3
 12500  -6.6  20.1  040   7  4   5.4   3.0 |  -5.5  22.1  015   7  4   6.2   3.4
 12000  -5.8  21.6  040   7  4   4.6   2.5 |  -4.7  23.5  020   7  4   5.2   2.8
 11500  -5.2  22.6  040   8  4   4.7   2.6 |  -3.9  25.0  025   7  4   5.2   2.8
 11000  -4.5  23.9  045   8  4   4.0   2.2 |  -3.2  26.2  030   7  3   4.6   2.5
 10500  -4.0  24.8  045   9  4   4.0   2.2 |  -2.5  27.5  035   7  3   4.8   2.6
 10250  -3.7  25.3  045   9  5   3.9   2.1 |  -2.2  28.0  040   7  3   3.7   2.0
 10000  -3.4  25.9  045   9  5   4.2   2.3 |  -2.0  28.4  040   7  3   3.1   1.7
  9750  -3.1  26.4  045   9  5   5.1   2.8 |  -1.8  28.8  045   7  4   4.0   2.2
  9500  -2.7  27.1  045  10  5   5.3   2.9 |  -1.5  29.3  045   7  4   4.0   2.2
  9250  -2.3  27.9  045  10  5   4.5   2.5 |  -1.2  29.8  050   7  4   3.6   2.0
  9000  -2.0  28.4  045  10  5   4.0   2.2 |  -1.0  30.2  050   8  4   3.3   1.8
  8750  -1.7  28.9  045  10  5   4.4   2.4 |  -0.7  30.7  050   9  5   3.5   1.9
  8500  -1.3  29.7  045  10  5   4.1   2.2 |  -0.5  31.1  050  10  5   3.5   1.9
  8250  -1.1  30.0  045   9  5   3.3   1.8 |  -0.2  31.6  050  10  5   3.6   1.9
  8000  -0.8  30.6  045   9  4   3.2   1.8 |   0.1  32.2  050  10  5   3.0   1.7
  7750  -0.5  31.1  045   8  4   3.2   1.7 |   0.4  32.7  055   9  5   5.1   2.8
  7500  -0.3  31.5  045   7  3   3.6   2.0 |   0.9  33.6  055   9  5   5.1   2.8
  7250   0.0  32.0  040   5  3   4.1   2.2 |   1.1  34.0  055   8  4   3.0   1.7
  7000   0.3  32.5  030   4  2   3.8   2.1 |   1.4  34.5  055   6  3   3.5   1.9
  6750   0.6  33.1  015   3  2   4.4   2.4 |   1.7  35.1  055   5  3   3.7   2.0
  6500   1.1  34.0  360   3  1   7.9   4.3 |   2.1  35.8  055   4  2   4.9   2.7
  6250   1.8  35.2  355   2  1   9.9   5.4 |   2.4  36.3  055   2  1   4.8   2.6
  6000   2.5  36.5  350   2  1   9.4   5.2 |   2.8  37.0  045   1  0   6.4   3.5
  5750   3.3  37.9  345   2  1  13.0   7.2 |   3.3  37.9  000   0  0   5.7   3.1
  5500   4.4  39.9  350   2  1  18.3  10.0 |   3.5  38.3  000   0  0  -0.9  -0.5
  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 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



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