Soaring Guidance
Issued by NWS Grand Junction, CO

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13
000
UXUS97 KGJT 281225
SRGGJT

Soaring Forecast
National Weather Service Grand Junction, Colorado
0625 MDT Tuesday, April 28, 2015

This forecast is for Tuesday, April 28, 2015:

If the trigger temperature of 60.9 F/16.1 C is reached...then
   Thermal Soaring Index....................... Excellent
   Maximum rate of lift........................ 860 ft/min (4.4 m/s)
   Maximum height of thermals.................. 15146 ft MSL (10307 ft AGL)

Forecast maximum temperature................... 71.0 F/22.1 C
Time of trigger temperature.................... 1200 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................. 11665 ft MSL (6826 ft AGL)
Thermal soaring outlook for Wednesday 04/29.... Excellent

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

Remarks...

Sunrise/Sunset.................... 06:19:58 / 20:03:07 MDT
Total possible sunshine........... 13 hr 43 min 9 sec (823 min 9 sec)
Altitude of sun at 13:11:42 MDT... 65.11 degrees

Upper air data from rawinsonde observation taken on 04/28/2015 at 0600 MDT

Freezing level.................. 10727 ft MSL (5888 ft AGL)
Convective condensation level... 12489 ft MSL (7650 ft AGL)
Lifted condensation level....... 13557 ft MSL (8718 ft AGL)
Lifted index.................... +0.4
K index......................... +17.8

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  -64.8 -84.6   015   30   15   9.4   5.2   91.9 197.4    40.1      M    M
 45000  -54.4 -65.9   345   52   27   5.7   3.1   83.4 182.2    37.9      M    M
 40000  -53.6 -64.5   360   52   27   3.4   1.9   61.8 143.2    26.3      M    M
 38000  -54.1 -65.4   025   40   21   3.8   2.1   52.2 125.9    20.5      M    M
 36000  -50.8 -59.4   030   65   34   5.7   3.1   48.4 119.2    18.5      M    M
 34000  -48.7 -55.7   030   72   37   5.0   2.7   43.1 109.6    15.2      M    M
 32000  -45.6 -50.1   035   80   41  -1.0  -0.5   38.4 101.1    12.2      M    M
 30000  -43.5 -46.3   030   43   22   6.5   3.5   33.2  91.8     8.7      M    M
 29000  -41.1 -42.0   030   43   22   8.4   4.6   32.6  90.7     8.3      M    M
 28000  -38.4 -37.1   030   44   23   9.5   5.2   32.3  90.1     8.1      M    M
 27000  -35.5 -31.9   025   44   23   9.5   5.2   32.1  89.7     8.1      M    M
 26000  -32.7 -26.9   025   45   23   9.5   5.2   32.0  89.6     8.2      M    M
 25000  -29.8 -21.6   025   45   23   9.5   5.2   32.1  89.7     8.3      M    M
 24000  -27.0 -16.6   030   43   22   9.1   5.0   31.9  89.4     8.2      M    M
 23000  -24.2 -11.6   030   41   21   9.3   5.1   31.7  89.0     8.2      M    M
 22000  -21.4  -6.5   035   40   21   8.9   4.9   31.5  88.8     8.2      M    M
 21000  -19.2  -2.6   035   39   20   7.1   3.9   30.7  87.3     7.6      M    M
 20000  -17.3   0.9   035   37   19   5.9   3.2   29.5  85.1     6.6      M    M
 19500  -16.4   2.5   035   34   17   5.9   3.2   28.8  83.9     6.1      M    M
 19000  -15.5   4.1   035   30   15   6.1   3.3   28.1  82.7     5.5      M    M
 18500  -14.8   5.4   035   26   14   4.2   2.3   27.3  81.2     4.9      M    M
 18000  -13.8   7.2   035   20   10   3.5   1.9   26.0  78.8     3.7      M    M
 17500  -13.4   7.9   020   12    6   2.6   1.4   24.7  76.5     2.6      M    M
 17000  -12.6   9.3   345    8    4   8.7   4.8   24.1  75.3     2.0      M    M
 16500  -11.4  11.5   335    8    4   8.3   4.5   23.8  74.8     1.7      M    M
 16000  -10.2  13.6   325    9    5   8.8   4.8   23.5  74.4     1.5      M    M
 15500   -9.4  15.1   340    9    5   0.8   0.4   22.9  73.2     0.8      M    M
 15000   -9.3  15.3   350    9    5   2.7   1.5   21.5  70.6    -0.5    849  4.3
 14500   -8.7  16.3   360   10    5   6.0   3.3   20.5  68.9    -1.4    817  4.1
 14000   -7.9  17.8   010   11    6   7.6   4.2   19.8  67.7    -2.1    779  4.0
 13500   -6.5  20.3   015   10    5   9.3   5.1   19.8  67.6    -2.2    722  3.7
 13000   -5.1  22.8   015    8    4   9.4   5.2   19.7  67.4    -2.2    665  3.4
 12500   -3.7  25.3   020    7    4   9.2   5.1   19.7  67.4    -2.3    608  3.1
 12000   -2.3  27.9   025    6    3   6.2   3.4   19.6  67.4    -2.4    552  2.8
 11500   -1.7  28.9   025    5    3   6.0   3.3   18.8  65.8    -3.3    520  2.6
 11000   -0.7  30.7   030    5    2   8.7   4.8   18.3  65.0    -3.8    475  2.4
 10500    0.6  33.1   035    4    2   9.2   5.0   18.2  64.8    -3.9    420  2.1
 10250    1.3  34.3   040    4    2   7.8   4.3   18.1  64.6    -4.0    393  2.0
 10000    1.8  35.2   050    5    2   6.7   3.6   17.9  64.2    -4.2    371  1.9
  9750    2.3  36.1   065    6    3   7.0   3.8   17.7  63.8    -4.5    349  1.8
  9500    2.8  37.0   070    7    3   6.9   3.8   17.4  63.4    -4.7    326  1.7
  9250    3.3  37.9   075    8    4   6.8   3.7   17.2  63.0    -5.0    304  1.5
  9000    3.8  38.8   080    9    5   7.3   4.0   17.0  62.6    -5.2    282  1.4
  8750    4.3  39.7   075    8    4   5.4   2.9   16.8  62.2    -5.4    259  1.3
  8500    4.5  40.1   070    7    4   2.4   1.3   16.3  61.3    -5.9    245  1.2
  8250    4.7  40.5   060    7    3   1.6   0.9   15.7  60.3    -6.5    233  1.2
  8000    4.9  40.8   050    6    3   5.5   3.0   15.2  59.3    -7.1    219  1.1
  7750    5.5  41.9   050    6    3   8.7   4.8   15.0  59.0    -7.2    194  1.0
  7500    6.1  43.0   050    6    3   7.8   4.3   14.9  58.8    -7.4    169  0.9
  7250    6.6  43.9   045    5    3   8.0   4.4   14.8  58.6    -7.5    144  0.7
  7000    7.2  45.0   045    5    3   8.0   4.4   14.6  58.3    -7.7    118  0.6
  6750    7.8  46.0   045    4    2   8.0   4.4   14.5  58.1    -7.8     93  0.5
  6500    8.4  47.1   040    3    2   8.0   4.4   14.4  57.8    -8.0     68  0.3
  6250    9.0  48.2   035    2    1   8.0   4.4   14.2  57.6    -8.2     43  0.2
  6000    9.6  49.3   025    1    1   7.8   4.3   14.1  57.4    -8.3     18  0.1
  5750   10.2  50.4   015    1    0   8.5   4.7   14.0  57.1    -8.5      M    M
  5500   10.8  51.4   015    1    0   5.9   3.2   13.8  56.9    -8.6      M    M
  5250   11.1  52.0   000    0    0   4.2   2.3   13.4  56.1    -9.1      M    M
  5000   11.2  52.2   000    0    0  -4.0  -2.2   12.8  55.1    -9.7      M    M

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

           04/28/2015 at 0900 MDT          |       04/28/2015 at 1200 MDT
                                           |
K index... +8.8  LI... +277.8              | K index... -3.7  LI... +276.9
CAPE... 0.0  CIN... M                      | CAPE... 0.0  CIN... M
                                           |
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 -60.2 -76.4  355  34 18   3.6   2.0 | -60.0 -76.0  355  32 16   3.5   1.9
 45000 -55.4 -67.7  360  41 21  -1.0  -0.5 | -55.6 -68.1  360  40 21  -1.0  -0.5
 40000 -57.0 -70.6  030  46 24  -0.9  -0.5 | -57.1 -70.8  020  43 22  -0.9  -0.5
 38000 -55.1 -67.2  035  54 28   4.7   2.6 | -55.2 -67.4  030  51 26   4.9   2.7
 36000 -52.2 -62.0  035  64 33   4.7   2.6 | -51.9 -61.4  035  62 32   4.9   2.7
 34000 -48.4 -55.1  035  70 36   7.0   3.9 | -48.5 -55.3  040  66 34   6.4   3.5
 32000 -44.2 -47.6  040  71 36   7.0   3.9 | -44.7 -48.5  035  61 32   6.4   3.5
 30000 -40.3 -40.5  035  65 33   5.7   3.1 | -40.3 -40.5  035  58 30   8.3   4.6
 29000 -38.6 -37.5  035  59 30   5.7   3.1 | -37.8 -36.0  035  58 30   8.3   4.6
 28000 -36.9 -34.4  030  53 28   5.7   3.1 | -35.3 -31.5  040  57 29   8.3   4.5
 27000 -34.9 -30.8  025  49 25   8.4   4.6 | -33.0 -27.4  040  55 28   7.0   3.8
 26000 -32.4 -26.3  025  47 24   8.3   4.5 | -30.9 -23.6  035  52 27   7.0   3.9
 25000 -30.0 -22.0  025  44 23   8.3   4.5 | -28.8 -19.8  035  49 25   7.0   3.9
 24000 -27.4 -17.3  025  42 22   9.1   5.0 | -26.6 -15.9  030  46 24   7.9   4.3
 23000 -24.7 -12.5  030  41 21   9.0   4.9 | -24.3 -11.7  030  42 22   7.8   4.3
 22000 -22.1  -7.8  030  40 21   9.0   4.9 | -22.0  -7.6  035  39 20   7.8   4.3
 21000 -19.4  -2.9  030  39 20   8.5   4.7 | -19.6  -3.3  035  36 18   8.3   4.6
 20000 -16.9   1.6  040  37 19   8.5   4.7 | -16.5   2.3  040  33 17   8.3   4.6
 19500 -15.6   3.9  040  37 19   8.5   4.7 | -15.2   4.6  045  31 16   8.3   4.6
 19000 -13.7   7.3  045  36 19   7.7   4.2 | -14.0   6.8  045  30 16   8.1   4.4
 18500 -12.6   9.3  050  34 17   6.9   3.8 | -12.8   9.0  045  29 15   7.9   4.3
 18000 -11.6  11.1  050  31 16   7.0   3.8 | -11.6  11.1  050  27 14   8.0   4.4
 17500 -10.6  12.9  050  28 14   6.0   3.3 | -10.5  13.1  050  25 13   6.8   3.7
 17000  -9.7  14.5  050  24 13   6.1   3.3 |  -9.4  15.1  050  24 12   7.0   3.8
 16500  -8.9  16.0  045  21 11   3.4   1.8 |  -8.4  16.9  050  22 11   5.8   3.2
 16000  -8.7  16.3  045  17  9   2.1   1.1 |  -7.6  18.3  050  19 10   5.3   2.9
 15500  -8.4  16.9  040  13  7   2.6   1.4 |  -6.9  19.6  050  17  9   4.4   2.4
 15000  -7.9  17.8  040  10  5   3.9   2.1 |  -6.5  20.3  055  14  7   2.5   1.4
 14500  -7.4  18.7  035   7  4   4.0   2.2 |  -6.1  21.0  055  11  6   2.8   1.5
 14000  -6.8  19.8  035   6  3   5.2   2.8 |  -5.6  21.9  055   9  5   4.9   2.7
 13500  -6.1  21.0  035   5  2   5.0   2.7 |  -5.0  23.0  065   7  3   4.9   2.7
 13000  -5.3  22.5  035   4  2   7.0   3.8 |  -4.3  24.3  070   5  3   5.2   2.8
 12500  -4.3  24.3  040   4  2   6.9   3.8 |  -3.6  25.5  070   4  2   5.0   2.7
 12000  -3.4  25.9  040   4  2   6.3   3.5 |  -2.7  27.1  075   3  2   7.3   4.0
 11500  -2.5  27.5  045   4  2   6.4   3.5 |  -1.7  28.9  075   3  1   7.3   4.0
 11000  -1.6  29.1  055   5  2   5.4   3.0 |  -0.7  30.7  080   3  1   6.2   3.4
 10500  -0.9  30.4  065   6  3   6.0   3.3 |   0.2  32.4  080   4  2   6.9   3.8
 10250  -0.5  31.1  070   7  4   3.5   1.9 |   0.6  33.1  085   4  2   3.4   1.9
 10000  -0.3  31.5  070   7  3   2.7   1.5 |   0.8  33.4  085   4  2   5.3   2.9
  9750  -0.0  32.0  070   6  3   4.6   2.5 |   1.5  34.7  090   4  2  10.1   5.5
  9500   0.2  32.4  070   5  3   4.1   2.3 |   2.1  35.8  090   4  2   8.7   4.8
  9250   0.6  33.1  075   5  2   8.0   4.4 |   2.7  36.9  095   4  2   6.0   3.3
  9000   1.4  34.5  080   4  2  10.4   5.7 |   3.1  37.6  100   3  2   4.9   2.7
  8750   2.1  35.8  085   3  2   9.6   5.3 |   3.5  38.3  105   2  1   6.9   3.8
  8500   2.8  37.0  095   3  1   8.9   4.9 |   4.0  39.2  120   2  1   7.2   3.9
  8250   3.4  38.1  115   2  1   7.1   3.9 |   4.5  40.1  135   1  1   7.4   4.0
  8000   3.9  39.0  125   3  1   6.6   3.6 |   5.1  41.2  155   1  0   7.7   4.2
  7750   4.4  39.9  135   3  2   7.5   4.1 |   5.6  42.1  175   1  0   8.8   4.8
  7500   5.0  41.0  145   4  2   6.7   3.7 |   6.3  43.3  195   1  0  10.0   5.5
  7250   5.5  41.9  145   4  2   5.6   3.1 |   7.1  44.8  200   1  1  10.2   5.6
  7000   5.9  42.6  150   4  2   5.9   3.2 |   7.8  46.0  205   1  1  10.2   5.6
  6750   6.3  43.3  155   4  2   5.8   3.2 |   8.6  47.5  210   1  1  10.0   5.5
  6500   6.8  44.2  165   4  2   6.0   3.3 |   9.3  48.7  210   1  1  10.2   5.6
  6250   7.2  45.0  170   3  2   6.2   3.4 |  10.1  50.2  215   1  1  10.6   5.8
  6000   7.6  45.7  175   3  1   5.8   3.2 |  10.9  51.6  220   2  1  10.2   5.6
  5750   8.1  46.6  180   3  1  10.9   6.0 |  11.8  53.2  215   2  1  17.3   9.5
  5500   9.3  48.7  180   2  1  20.6  11.3 |  13.6  56.5  220   1  1  29.3  16.1
  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

           04/28/2015 at 1500 MDT          |       04/28/2015 at 1800 MDT
                                           |
K index... -5.6  LI... +275.3              | K index... -2.2  LI... +275.5
CAPE... 0.0  CIN... -0.6                   | CAPE... 0.0  CIN... -0.5
                                           |
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 -60.6 -77.1  355  26 14   3.5   1.9 | -60.6 -77.1  345  27 14   3.0   1.7
 45000 -56.2 -69.2  360  35 18  -0.9  -0.5 | -56.8 -70.2  350  37 19  -0.8  -0.4
 40000 -57.7 -71.9  020  45 23  -0.9  -0.5 | -58.0 -72.4  015  41 21  -0.9  -0.5
 38000 -55.5 -67.9  030  51 26   5.1   2.8 | -55.7 -68.3  025  46 24   5.2   2.8
 36000 -52.4 -62.3  040  58 30   5.1   2.8 | -52.6 -62.7  035  52 27   5.2   2.8
 34000 -48.3 -54.9  040  59 30   7.2   3.9 | -48.1 -54.6  040  53 27   7.9   4.4
 32000 -44.0 -47.2  035  53 27   7.2   3.9 | -43.3 -45.9  040  50 26   7.9   4.4
 30000 -39.5 -39.1  030  49 25   7.9   4.3 | -38.7 -37.7  040  46 24   7.7   4.2
 29000 -37.1 -34.8  030  48 25   7.9   4.3 | -36.4 -33.5  035  44 23   7.7   4.2
 28000 -34.7 -30.5  030  47 24   7.9   4.3 | -34.1 -29.4  030  43 22   7.7   4.2
 27000 -32.4 -26.3  030  46 24   7.8   4.3 | -31.7 -25.1  030  41 21   7.9   4.3
 26000 -30.0 -22.0  035  44 22   7.8   4.3 | -29.4 -20.9  030  38 20   7.9   4.3
 25000 -27.6 -17.7  035  42 21   7.8   4.3 | -27.0 -16.6  030  36 19   7.9   4.3
 24000 -25.3 -13.5  040  40 20   7.4   4.0 | -24.6 -12.3  030  33 17   7.7   4.2
 23000 -23.1  -9.6  040  37 19   7.4   4.1 | -22.3  -8.1  035  30 15   7.7   4.2
 22000 -20.9  -5.6  045  35 18   7.4   4.1 | -20.0  -4.0  040  27 14   7.6   4.2
 21000 -18.7  -1.7  045  32 16   7.3   4.0 | -17.9  -0.2  045  24 12   6.7   3.7
 20000 -16.5   2.3  045  28 14   7.3   4.0 | -15.9   3.4  045  22 11   6.7   3.7
 19500 -15.4   4.3  045  26 13   7.3   4.0 | -14.8   5.4  050  20 10   6.8   3.7
 19000 -14.3   6.3  040  24 12   7.5   4.1 | -13.8   7.2  050  19 10   7.0   3.8
 18500 -13.1   8.4  045  22 12   8.4   4.6 | -12.7   9.1  050  18  9   8.3   4.5
 18000 -11.9  10.6  045  21 11   8.4   4.6 | -11.4  11.5  045  17  9   8.2   4.5
 17500 -10.6  12.9  045  20 10   7.5   4.1 | -10.2  13.6  045  17  9   7.8   4.3
 17000  -9.5  14.9  045  18 10   7.3   4.0 |  -9.1  15.6  045  16  8   7.6   4.2
 16500  -8.4  16.9  045  17  9   7.1   3.9 |  -7.9  17.8  040  16  8   7.3   4.0
 16000  -7.4  18.7  050  15  8   6.4   3.5 |  -6.9  19.6  040  15  8   6.7   3.7
 15500  -6.0  21.2  055  13  7   5.3   2.9 |  -5.5  22.1  045  13  7   6.0   3.3
 15000  -5.3  22.5  060  11  6   4.6   2.5 |  -4.6  23.7  050  12  6   5.5   3.0
 14500  -4.7  23.5  065   9  5   4.5   2.5 |  -3.8  25.2  060  11  6   5.6   3.1
 14000  -4.0  24.8  065   8  4   4.6   2.5 |  -3.0  26.6  070  10  5   6.1   3.3
 13500  -3.4  25.9  070   6  3   4.9   2.7 |  -2.1  28.2  075   9  4   6.1   3.3
 13000  -2.6  27.3  075   5  2   6.4   3.5 |  -1.2  29.8  075   7  4   6.0   3.3
 12500  -1.7  28.9  090   4  2   6.4   3.5 |  -0.4  31.3  070   5  3   6.1   3.3
 12000  -0.7  30.7  095   3  1   7.1   3.9 |   0.6  33.1  060   5  2   7.5   4.1
 11500   0.3  32.5  090   2  1   7.1   3.9 |   1.7  35.1  050   4  2   7.4   4.0
 11000   1.4  34.5  070   1  1   7.1   3.9 |   2.8  37.0  045   4  2   7.6   4.2
 10500   2.4  36.3  040   1  1   5.9   3.2 |   3.9  39.0  035   4  2   6.2   3.4
 10250   2.8  37.0  035   1  1   4.6   2.5 |   4.3  39.7  035   4  2   5.1   2.8
 10000   3.2  37.8  020   1  1   7.6   4.2 |   4.7  40.5  035   4  2   8.4   4.6
  9750   3.8  38.8  360   1  1   9.5   5.2 |   5.4  41.7  030   4  2   9.9   5.4
  9500   4.5  40.1  345   2  1   8.1   4.4 |   6.1  43.0  025   3  2   9.1   5.0
  9250   5.0  41.0  335   2  1   5.5   3.0 |   6.7  44.1  020   3  2   7.5   4.1
  9000   5.3  41.5  325   2  1   6.7   3.7 |   7.3  45.1  015   3  1   7.5   4.1
  8750   5.9  42.6  325   2  1   8.4   4.6 |   7.9  46.2  360   2  1   8.5   4.7
  8500   6.4  43.5  320   2  1   8.4   4.6 |   8.5  47.3  345   2  1   7.9   4.3
  8250   7.0  44.6  320   3  1   8.6   4.7 |   9.0  48.2  325   2  1   7.2   4.0
  8000   7.7  45.9  315   3  1   9.6   5.3 |   9.5  49.1  310   2  1   7.2   3.9
  7750   8.4  47.1  315   3  1  11.0   6.0 |  10.0  50.0  300   3  1   6.9   3.8
  7500   9.2  48.6  310   3  1  10.4   5.7 |  10.6  51.1  290   3  2   8.3   4.5
  7250  10.0  50.0  305   3  1   9.9   5.4 |  11.2  52.2  290   3  2   9.5   5.2
  7000  10.7  51.3  305   3  1  10.1   5.6 |  11.8  53.2  285   3  2   9.4   5.2
  6750  11.5  52.7  300   3  1  10.6   5.8 |  12.5  54.5  280   3  2  10.1   5.5
  6500  12.3  54.1  300   3  1  10.8   5.9 |  13.3  55.9  280   4  2  10.4   5.7
  6250  13.1  55.6  295   3  1  11.1   6.1 |  14.0  57.2  275   4  2  10.8   5.9
  6000  13.9  57.0  295   3  1  10.1   5.6 |  14.8  58.6  275   4  2   9.4   5.2
  5750  14.7  58.5  295   3  1  12.6   6.9 |  15.5  59.9  270   4  2   9.4   5.2
  5500  15.8  60.4  295   3  1  15.9   8.7 |  16.2  61.2  275   4  2  11.0   6.0
  5250  16.9  62.4  295   3  2  13.3   7.3 |  17.0  62.6  280   4  2   9.7   5.3
  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.