Soaring Guidance
Issued by NWS Grand Junction, CO

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000
UXUS97 KGJT 141243
SRGGJT

Soaring Forecast
National Weather Service Grand Junction, Colorado
0543 MST Thursday, December 14, 2017

This forecast is for Thursday, December 14, 2017:

If the trigger temperature of 44.4 F/6.9 C is reached...then
   Thermal Soaring Index....................... Fair
   Maximum rate of lift........................ 342 ft/min (1.7 m/s)
   Maximum height of thermals.................. 9839 ft MSL (5000 ft AGL)

Forecast maximum temperature................... 47.0 F/8.8 C
Time of trigger temperature.................... 1245 MST
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................. 5648 ft MSL (808 ft AGL)
Thermal soaring outlook for Friday 12/15....... Fair

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

Remarks...

Sunrise/Sunset.................... 07:25:38 / 16:52:28 MST
Total possible sunshine........... 9 hr 26 min 49 sec (566 min 49 sec)
Altitude of sun at 12:09:05 MST... 27.70 degrees

Upper air data from rawinsonde observation taken on 12/14/2017 at 0500 MST

Freezing level.................. 6776 ft MSL (1937 ft AGL)
Convective condensation level... 11559 ft MSL (6720 ft AGL)
Lifted condensation level....... 10875 ft MSL (6036 ft AGL)
Lifted index.................... +6.7
K index......................... +13.5

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  -59.4 -74.9   320   24   12  -6.0  -3.3  104.0 219.1    54.2      M    M
 45000  -53.5 -64.3   305   41   21  -3.9  -2.2   87.8 190.0    48.3      M    M
 40000  -54.1 -65.4   330   43   22  -2.8  -1.5   63.7 146.6    36.0      M    M
 38000  -53.2 -63.8   345   24   12   7.4   4.1   56.1 133.0    31.9      M    M
 36000  -50.3 -58.5   010   26   13   4.8   2.6   51.8 125.2    29.8      M    M
 34000  -52.9 -63.2   355   30   15   0.2   0.1   39.6 103.3    22.0      M    M
 32000  -48.0 -54.4   005   31   16   5.0   2.7   37.3  99.1    21.0      M    M
 30000  -43.9 -47.0   350   28   14   7.7   4.3   34.9  94.8    19.8      M    M
 29000  -41.5 -42.7   340   27   14   8.0   4.4   34.1  93.4    19.5      M    M
 28000  -39.1 -38.4   330   26   13   8.0   4.4   33.5  92.3    19.2      M    M
 27000  -36.8 -34.2   345   25   13   1.6   0.9   32.7  90.8    18.8      M    M
 26000  -36.6 -33.9   360   25   13   4.5   2.5   29.1  84.4    16.3      M    M
 25000  -35.4 -31.7   015   27   14   1.9   1.1   27.0  80.7    14.8      M    M
 24000  -34.2 -29.6   025   36   18   6.6   3.6   24.9  76.8    13.2      M    M
 23000  -32.4 -26.3   020   41   21   8.2   4.5   23.5  74.3    12.3      M    M
 22000  -30.1 -22.2   005   32   16   7.8   4.3   22.8  73.1    11.8      M    M
 21000  -27.7 -17.9   010   30   15   8.3   4.6   22.1  71.8    11.4      M    M
 20000  -25.2 -13.4   015   29   15   8.3   4.5   21.6  70.9    11.0      M    M
 19500  -24.0 -11.2   020   29   15   8.3   4.5   21.3  70.4    10.9      M    M
 19000  -22.8  -9.0   020   29   15   8.3   4.5   21.0  69.9    10.7      M    M
 18500  -21.6  -6.9   025   29   15   8.3   4.5   20.8  69.4    10.5      M    M
 18000  -19.8  -3.6   025   32   17   7.9   4.3   20.3  68.5    10.2      M    M
 17500  -18.6  -1.5   020   35   18   7.8   4.3   20.0  68.0     9.9      M    M
 17000  -17.5   0.5   020   37   19   5.3   2.9   19.7  67.4     9.7      M    M
 16500  -17.0   1.4   015   35   18   3.4   1.8   18.5  65.4     8.7      M    M
 16000  -16.5   2.3   015   33   17   3.2   1.8   17.4  63.4     7.8      M    M
 15500  -16.0   3.2   010   32   17   5.5   3.0   16.4  61.5     6.9      M    M
 15000  -15.0   5.0   005   31   16   6.7   3.7   15.9  60.6     6.5      M    M
 14500  -14.0   6.8   010   28   14   7.7   4.2   15.4  59.7     6.1      M    M
 14000  -13.6   7.5   010   25   13  -2.3  -1.3   14.3  57.7     5.1      M    M
 13500  -13.5   7.7   015   24   12   3.6   2.0   12.7  54.9     3.7      M    M
 13000  -12.8   9.0   025   24   12   4.6   2.5   11.9  53.4     2.9      M    M
 12500  -12.0  10.4   030   24   12   7.0   3.9   11.2  52.2     2.3      M    M
 12000  -10.9  12.4   035   24   12   7.5   4.1   10.9  51.6     2.0      M    M
 11500   -9.8  14.4   030   24   13   7.5   4.1   10.5  50.9     1.7      M    M
 11000   -8.7  16.3   030   25   13   7.4   4.1   10.1  50.2     1.3      M    M
 10500   -7.5  18.5   025   25   13   6.2   3.4    9.8  49.6     1.0      M    M
 10250   -7.2  19.0   025   26   13   4.4   2.4    9.4  48.9     0.6      M    M
 10000   -6.8  19.8   025   26   13   5.1   2.8    9.0  48.2     0.2      M    M
  9750   -6.5  20.3   025   25   13   5.3   2.9    8.6  47.5    -0.1    336  1.7
  9500   -6.1  21.0   025   24   13   5.2   2.9    8.3  46.9    -0.5    317  1.6
  9250   -5.7  21.7   030   24   12   5.3   2.9    7.9  46.3    -0.8    298  1.5
  9000   -5.3  22.5   030   23   12   5.3   2.9    7.6  45.7    -1.1    279  1.4
  8750   -4.9  23.2   030   23   12   5.2   2.9    7.2  45.0    -1.5    260  1.3
  8500   -4.5  23.9   025   23   12   5.4   3.0    6.9  44.4    -1.9    241  1.2
  8250   -4.2  24.4   025   23   12   4.7   2.6    6.5  43.7    -2.2    223  1.1
  8000   -3.8  25.2   020   23   12   7.4   4.1    6.2  43.1    -2.6    204  1.0
  7750   -3.0  26.6   015   22   11  11.0   6.0    6.2  43.1    -2.6    174  0.9
  7500   -2.2  28.0   015   21   11  11.3   6.2    6.3  43.3    -2.5    142  0.7
  7250   -1.4  29.5   010   20   10  10.0   5.5    6.4  43.5    -2.4    109  0.6
  7000   -0.7  30.7   005   19   10   8.4   4.6    6.3  43.4    -2.4     82  0.4
  6750   -0.1  31.8   005   18    9   8.6   4.7    6.2  43.2    -2.5     56  0.3
  6500    0.6  33.1   005   16    8   8.6   4.7    6.1  43.1    -2.6     29  0.1
  6250    1.2  34.2   360   15    8   8.6   4.7    6.1  42.9    -2.7      3  0.0
  6000    1.8  35.2   360   13    7   8.5   4.7    6.0  42.8    -2.8      M    M
  5750    2.5  36.5   360   12    6   8.6   4.7    5.9  42.6    -2.9      M    M
  5500    3.1  37.6   355   10    5   8.3   4.5    5.8  42.4    -3.0      M    M
  5250    3.7  38.7   355    9    5   9.6   5.3    5.7  42.2    -3.1      M    M
  5000    4.4  39.9   350    8    4   4.6   2.5    5.6  42.1    -3.2      M    M

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

           12/14/2017 at 0800 MST          |       12/14/2017 at 1100 MST
                                           |
K index... -7.8  LI... +5.0                | K index... -21.0  LI... +7.4
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 -57.1 -70.8  335  27 14   1.7   1.0 | -57.4 -71.3  335  25 13   1.6   0.9
 45000 -54.3 -65.7  330  39 20   1.3   0.7 | -54.9 -66.8  345  33 17   0.9   0.5
 40000 -54.1 -65.4  350  31 16   0.1   0.1 | -56.1 -69.0  005  43 22  -0.8  -0.5
 38000 -53.6 -64.5  005  37 19   1.9   1.1 | -55.7 -68.3  010  54 28   3.0   1.6
 36000 -52.5 -62.5  015  57 29   1.9   1.1 | -53.9 -65.0  020  74 38   2.9   1.6
 34000 -51.3 -60.3  020  78 40   3.4   1.9 | -51.7 -61.1  020  94 48   5.7   3.1
 32000 -47.9 -54.2  025  81 41   5.1   2.8 | -48.4 -55.1  025  96 49   5.4   3.0
 30000 -44.8 -48.6  025  82 42   5.9   3.2 | -45.0 -49.0  025  98 50   6.8   3.7
 29000 -43.1 -45.6  025  78 40   5.8   3.2 | -43.0 -45.4  025  97 50   6.7   3.7
 28000 -41.4 -42.5  025  74 38   5.8   3.2 | -41.0 -41.8  025  95 49   6.7   3.7
 27000 -39.6 -39.3  025  70 36   5.7   3.2 | -39.0 -38.2  025  94 48   6.7   3.7
 26000 -37.8 -36.0  025  66 34   6.3   3.4 | -37.0 -34.6  025  92 47   6.6   3.6
 25000 -35.9 -32.6  025  62 32   6.3   3.4 | -35.0 -31.0  025  89 46   6.6   3.6
 24000 -34.0 -29.2  025  58 30   6.2   3.4 | -33.0 -27.4  025  87 45   6.6   3.6
 23000 -32.0 -25.6  025  54 28   6.9   3.8 | -31.1 -24.0  025  83 43   6.4   3.5
 22000 -29.9 -21.8  025  51 26   6.9   3.8 | -29.2 -20.6  025  78 40   6.5   3.5
 21000 -27.9 -18.2  020  47 24   7.0   3.8 | -27.2 -17.0  025  74 38   6.7   3.7
 20000 -25.7 -14.3  025  45 23   7.3   4.0 | -25.1 -13.2  025  66 34   7.1   3.9
 19500 -24.6 -12.3  025  43 22   7.3   4.0 | -23.5 -10.3  030  61 31   7.1   3.9
 19000 -23.0  -9.4  025  42 21   7.3   4.0 | -22.4  -8.3  030  58 30   7.1   3.9
 18500 -21.9  -7.4  025  41 21   7.7   4.2 | -21.3  -6.3  030  54 28   7.8   4.3
 18000 -20.7  -5.3  025  41 21   7.8   4.3 | -20.2  -4.4  030  51 26   7.9   4.3
 17500 -19.5  -3.1  025  40 21   7.7   4.2 | -19.0  -2.2  030  47 24   8.0   4.4
 17000 -18.4  -1.1  025  40 21   7.1   3.9 | -17.7   0.1  030  43 22   8.2   4.5
 16500 -17.4   0.7  030  40 21   7.2   4.0 | -16.5   2.3  030  38 19   8.3   4.6
 16000 -16.3   2.7  030  40 20   6.3   3.5 | -15.4   4.3  030  35 18   6.2   3.4
 15500 -15.4   4.3  030  40 20   6.4   3.5 | -14.5   5.9  030  33 17   6.5   3.5
 15000 -14.5   5.9  035  39 20   6.2   3.4 | -13.6   7.5  030  32 17   5.3   2.9
 14500 -13.6   7.5  035  38 20   6.2   3.4 | -12.8   9.0  030  34 18   5.2   2.8
 14000 -12.7   9.1  035  37 19   5.7   3.1 | -12.1  10.2  030  36 18   4.2   2.3
 13500 -11.9  10.6  035  35 18   5.3   2.9 | -11.5  11.3  030  34 18   3.9   2.1
 13000 -11.2  11.8  035  32 17   5.2   2.9 | -10.9  12.4  035  33 17   3.9   2.2
 12500 -10.4  13.3  040  30 15   5.2   2.8 | -10.4  13.3  035  31 16   4.1   2.2
 12000  -9.7  14.5  040  27 14   5.5   3.0 |  -9.8  14.4  040  29 15   4.6   2.5
 11500  -8.8  16.2  040  26 13   5.8   3.2 |  -9.1  15.6  040  27 14   5.0   2.7
 11000  -8.0  17.6  040  24 13   5.9   3.2 |  -8.3  17.1  040  26 13   5.2   2.9
 10500  -7.2  19.0  045  22 11   6.0   3.3 |  -7.6  18.3  040  25 13   5.2   2.9
 10250  -6.7  19.9  045  21 11   5.4   2.9 |  -7.2  19.0  040  24 12   5.6   3.1
 10000  -6.4  20.5  045  20 11   4.0   2.2 |  -6.7  19.9  040  24 12   6.4   3.5
  9750  -6.1  21.0  045  19 10   6.3   3.5 |  -6.3  20.7  040  24 12   6.6   3.6
  9500  -5.5  22.1  050  18  9   8.9   4.9 |  -5.8  21.6  040  23 12   6.4   3.5
  9250  -4.9  23.2  055  17  9   7.3   4.0 |  -5.3  22.5  040  23 12   6.4   3.5
  9000  -4.4  24.1  055  17  9   4.9   2.7 |  -4.9  23.2  040  22 11   6.1   3.4
  8750  -4.1  24.6  060  18  9   5.1   2.8 |  -4.4  24.1  040  22 11   6.8   3.7
  8500  -3.7  25.3  060  19 10   6.4   3.5 |  -3.9  25.0  045  20 10   7.2   4.0
  8250  -3.2  26.2  060  21 11   4.9   2.7 |  -3.4  25.9  045  19 10   6.4   3.5
  8000  -2.9  26.8  055  22 11   4.1   2.3 |  -3.0  26.6  045  19 10   6.1   3.4
  7750  -2.6  27.3  050  24 12   3.1   1.7 |  -2.5  27.5  045  19 10   5.5   3.0
  7500  -2.5  27.5  045  26 13   1.5   0.8 |  -2.2  28.0  040  19 10   4.0   2.2
  7250  -2.4  27.7  045  26 14   1.6   0.9 |  -1.9  28.6  035  18  9   3.7   2.0
  7000  -2.3  27.9  040  26 13   1.7   0.9 |  -1.7  28.9  030  16  8   3.0   1.6
  6750  -2.2  28.0  035  25 13   1.1   0.6 |  -1.5  29.3  025  15  7   5.5   3.0
  6500  -2.1  28.2  035  23 12   3.7   2.0 |  -0.9  30.4  025  13  7   9.6   5.3
  6250  -1.7  28.9  035  20 10   5.8   3.2 |  -0.1  31.8  025  13  6  10.1   5.6
  6000  -1.2  29.8  035  17  9   6.2   3.4 |   0.6  33.1  025  12  6  10.1   5.5
  5750  -0.8  30.6  035  14  7   2.5   1.4 |   1.5  34.7  025  11  6  14.7   8.1
  5500  -1.1  30.0  030   9  5  -8.9  -4.9 |   2.9  37.2  020  11  6  22.0  12.1
  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

           12/14/2017 at 1400 MST          |       12/14/2017 at 1700 MST
                                           |
K index... -27.2  LI... +8.2               | K index... -39.3  LI... +8.9
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 -57.6 -71.7  330  27 14   1.4   0.8 | -57.7 -71.9  345  24 12   0.9   0.5
 45000 -55.5 -67.9  345  32 17   0.8   0.5 | -56.2 -69.2  360  32 16   0.1   0.1
 40000 -56.0 -68.8  010  53 27  -0.4  -0.2 | -58.1 -72.6  020  63 33  -1.3  -0.7
 38000 -55.6 -68.1  015  63 33   2.0   1.1 | -57.5 -71.5  020  79 41   3.8   2.1
 36000 -54.4 -65.9  020  75 39   2.0   1.1 | -55.2 -67.4  020  97 50   3.8   2.1
 34000 -52.5 -62.5  020  87 45   6.9   3.8 | -52.8 -63.0  020 113 58   5.9   3.2
 32000 -48.6 -55.5  020  90 46   6.6   3.6 | -48.8 -55.8  020 100 52   6.0   3.3
 30000 -44.7 -48.5  020  91 47   6.6   3.6 | -45.0 -49.0  020  90 46   7.3   4.0
 29000 -42.7 -44.9  020  89 46   6.7   3.7 | -42.8 -45.0  020  86 44   7.3   4.0
 28000 -40.7 -41.3  020  87 45   6.7   3.7 | -40.6 -41.1  020  82 42   7.3   4.0
 27000 -38.7 -37.7  020  85 44   6.7   3.7 | -38.4 -37.1  025  79 40   7.5   4.1
 26000 -36.6 -33.9  020  83 43   7.0   3.9 | -36.1 -33.0  025  76 39   7.6   4.2
 25000 -34.5 -30.1  020  80 41   7.0   3.9 | -33.9 -29.0  020  73 38   7.6   4.2
 24000 -32.4 -26.3  020  77 40   7.0   3.9 | -31.6 -24.9  020  71 36   7.6   4.2
 23000 -30.2 -22.4  020  75 39   7.2   4.0 | -29.4 -20.9  020  68 35   7.1   3.9
 22000 -28.1 -18.6  020  73 38   7.2   4.0 | -27.3 -17.1  020  65 33   7.1   3.9
 21000 -25.9 -14.6  020  72 37   6.8   3.7 | -25.2 -13.4  020  62 32   6.7   3.7
 20000 -24.0 -11.2  025  68 35   6.2   3.4 | -23.3  -9.9  020  58 30   6.4   3.5
 19500 -22.6  -8.7  025  66 34   6.2   3.4 | -22.3  -8.1  020  57 29   6.4   3.5
 19000 -21.7  -7.1  025  64 33   6.3   3.5 | -20.9  -5.6  020  54 28   6.3   3.5
 18500 -20.8  -5.4  025  61 32   5.4   3.0 | -19.9  -3.8  020  53 27   7.1   3.9
 18000 -20.0  -4.0  025  56 29   5.3   2.9 | -18.8  -1.8  025  52 27   7.1   3.9
 17500 -19.2  -2.6  025  51 26   5.3   2.9 | -17.7   0.1  025  51 26   6.9   3.8
 17000 -18.4  -1.1  025  47 24   5.2   2.9 | -16.7   1.9  025  50 26   6.8   3.7
 16500 -17.6   0.3  020  43 22   5.2   2.9 | -15.7   3.7  025  48 25   6.7   3.7
 16000 -16.6   2.1  020  41 21   8.8   4.8 | -14.7   5.5  025  47 24   6.0   3.3
 15500 -15.3   4.5  020  40 21   8.5   4.7 | -13.8   7.2  025  45 23   6.2   3.4
 15000 -14.1   6.6  015  38 20   8.0   4.4 | -13.0   8.6  025  43 22   4.8   2.6
 14500 -12.9   8.8  010  35 18   8.1   4.4 | -12.3   9.9  025  42 22   4.8   2.7
 14000 -11.7  10.9  010  32 16   6.7   3.7 | -11.6  11.1  020  41 21   5.0   2.7
 13500 -10.8  12.6  015  33 17   6.3   3.5 | -10.8  12.6  020  41 21   5.0   2.7
 13000  -9.9  14.2  015  33 17   5.2   2.9 | -10.0  14.0  020  40 21   5.7   3.1
 12500  -9.2  15.4  020  34 18   4.7   2.6 |  -9.1  15.6  020  40 20   6.0   3.3
 12000  -8.5  16.7  025  35 18   3.7   2.0 |  -8.3  17.1  020  39 20   4.3   2.4
 11500  -8.1  17.4  025  34 18   3.2   1.7 |  -7.8  18.0  025  39 20   3.6   2.0
 11000  -7.6  18.3  030  34 17   2.3   1.3 |  -7.2  19.0  025  39 20   4.1   2.2
 10500  -7.4  18.7  035  33 17   2.0   1.1 |  -6.6  20.1  025  38 20   4.5   2.5
 10250  -7.2  19.0  035  33 17   2.2   1.2 |  -6.3  20.7  025  38 19   3.1   1.7
 10000  -7.1  19.2  035  33 17   3.2   1.8 |  -6.2  20.8  030  37 19   1.1   0.6
  9750  -6.8  19.8  035  31 16   4.1   2.3 |  -6.1  21.0  030  36 19   2.1   1.2
  9500  -6.5  20.3  035  29 15   4.0   2.2 |  -5.9  21.4  030  34 18   2.6   1.4
  9250  -6.2  20.8  035  26 14   5.3   2.9 |  -5.7  21.7  030  33 17   3.4   1.9
  9000  -5.8  21.6  035  25 13   6.8   3.7 |  -5.4  22.3  035  31 16   4.5   2.4
  8750  -5.3  22.5  035  23 12   7.9   4.3 |  -5.1  22.8  035  29 15   4.8   2.6
  8500  -4.7  23.5  035  22 11   8.9   4.9 |  -4.7  23.5  035  26 13   5.3   2.9
  8250  -4.0  24.8  035  21 11   9.4   5.1 |  -4.4  24.1  035  23 12   5.5   3.0
  8000  -3.3  26.1  035  20 10   9.8   5.4 |  -4.0  24.8  040  22 11   5.3   2.9
  7750  -2.6  27.3  035  20 10   9.8   5.4 |  -3.6  25.5  040  20 10   6.8   3.8
  7500  -1.8  28.8  035  20 10  10.0   5.5 |  -3.0  26.6  035  20 10   9.1   5.0
  7250  -1.1  30.0  035  19 10   9.9   5.4 |  -2.3  27.9  035  20 10   9.1   5.0
  7000  -0.3  31.5  035  19 10   9.9   5.4 |  -1.7  28.9  035  20 10   9.3   5.1
  6750   0.4  32.7  035  19 10   9.9   5.4 |  -1.0  30.2  035  19 10   8.6   4.7
  6500   1.2  34.2  035  18  9  10.3   5.7 |  -0.4  31.3  035  18  9   8.6   4.7
  6250   1.9  35.4  035  17  9  10.8   5.9 |   0.3  32.5  035  16  8   9.0   4.9
  6000   2.7  36.9  035  16  8  10.1   5.5 |   1.0  33.8  035  14  7   9.9   5.4
  5750   3.6  38.5  035  16  8  13.9   7.6 |   1.6  34.9  035  14  7   4.6   2.5
  5500   4.9  40.8  035  15  8  21.8  12.0 |   1.5  34.7  035  11  6  -7.4  -4.0
  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
________________________________________________________________________________

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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