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
000
UXUS97 KGJT 251233
SRGGJT

Soaring Forecast
National Weather Service Grand Junction, Colorado
0633 MDT Friday, May 25, 2018

This forecast is for Friday, May 25, 2018:

If the trigger temperature of 81.6 F/27.5 C is reached...then
   Thermal Soaring Index....................... Excellent
   Maximum rate of lift........................ 1484 ft/min (7.5 m/s)
   Maximum height of thermals.................. 20490 ft MSL (15651 ft AGL)

Forecast maximum temperature................... 93.0 F/34.3 C
Time of trigger temperature.................... 1045 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................. 18004 ft MSL (13165 ft AGL)
Thermal soaring outlook for Saturday 05/26..... Excellent

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

Remarks...

Sunrise/Sunset.................... 05:53:43 / 20:28:20 MDT
Total possible sunshine........... 14 hr 34 min 37 sec (874 min 37 sec)
Altitude of sun at 13:11:13 MDT... 71.91 degrees

Upper air data from rawinsonde observation taken on 05/25/2018 at 0600 MDT

Freezing level.................. 14476 ft MSL (9637 ft AGL)
Convective condensation level... 20610 ft MSL (15771 ft AGL)
Lifted condensation level....... 20881 ft MSL (16042 ft AGL)
Lifted index.................... -1.2
K index......................... +5.6

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  -61.8 -79.2   250   34   17   0.6   0.3   94.2 201.5    34.7      M    M
 45000  -57.2 -71.0   255   29   15  -1.1  -0.6   77.4 171.4    26.8      M    M
 40000  -57.7 -71.9   220   24   12   6.7   3.7   52.3 126.2    12.2      M    M
 38000  -53.8 -64.8   225   19   10   6.4   3.5   49.3 120.7    10.5      M    M
 36000  -49.7 -57.5   230   20   10   8.8   4.8   46.9 116.4     9.1      M    M
 34000  -45.4 -49.7   240   21   11   5.5   3.0   44.8 112.6     7.8      M    M
 32000  -41.1 -42.0   250   22   11   7.8   4.3   42.5 108.5     6.3      M    M
 30000  -36.1 -33.0   260   27   14   6.9   3.8   40.6 105.1     5.1      M    M
 29000  -34.0 -29.2   265   30   15   6.4   3.5   39.4 103.0     4.3      M    M
 28000  -32.2 -26.0   250   32   16   7.3   4.0   38.0 100.5     3.2      M    M
 27000  -29.4 -20.9   255   30   15   9.5   5.2   37.8 100.1     3.1      M    M
 26000  -26.6 -15.9   260   28   15   8.9   4.9   37.8 100.1     3.1      M    M
 25000  -24.3 -11.7   265   27   14   7.7   4.2   37.0  98.6     2.5      M    M
 24000  -22.3  -8.1   260   26   14   6.4   3.5   35.9  96.6     1.6      M    M
 23000  -20.2  -4.4   255   25   13   9.0   4.9   34.9  94.8     0.8      M    M
 22000  -17.5   0.5   250   25   13   8.7   4.8   34.4  94.0     0.4      M    M
 21000  -14.9   5.2   245   24   12   8.7   4.8   34.1  93.3     0.1      M    M
 20000  -12.4   9.7   240   24   12   7.4   4.1   33.8  92.8    -0.1   1438  7.3
 19500  -11.4  11.5   235   23   12   6.8   3.7   33.2  91.8    -0.6   1393  7.1
 19000  -10.3  13.5   225   22   11   6.9   3.8   32.7  90.9    -1.0   1348  6.9
 18500   -9.7  14.5   225   22   11   2.7   1.5   31.8  89.3    -1.8   1313  6.7
 18000   -9.2  15.4   225   22   11   3.9   2.1   30.7  87.2    -2.9   1285  6.5
 17500   -8.3  17.1   225   21   11   8.0   4.4   30.1  86.2    -3.4   1242  6.3
 17000   -7.1  19.2   230   21   11   7.8   4.3   29.8  85.6    -3.8   1193  6.1
 16500   -5.4  22.3   230   21   11   8.9   4.9   29.3  84.8    -4.2   1119  5.7
 16000   -4.0  24.8   230   21   11   9.5   5.2   29.3  84.7    -4.3   1061  5.4
 15500   -2.5  27.5   230   20   11   9.5   5.2   29.3  84.7    -4.3   1003  5.1
 15000   -1.2  29.8   230   20   10   9.2   5.0   29.2  84.5    -4.5    948  4.8
 14500    0.2  32.4   230   19   10   9.2   5.1   29.1  84.3    -4.6    893  4.5
 14000    1.5  34.7   230   19   10   9.3   5.1   29.0  84.2    -4.7    838  4.3
 13500    2.8  37.0   230   16    8   9.3   5.1   28.9  84.1    -4.9    784  4.0
 13000    4.2  39.6   230   14    7   9.2   5.0   28.8  83.9    -5.0    728  3.7
 12500    5.6  42.1   225   12    6   9.2   5.0   28.8  83.8    -5.1    672  3.4
 12000    6.9  44.4   225   10    5   9.2   5.0   28.7  83.6    -5.2    617  3.1
 11500    8.3  46.9   215   10    5   9.2   5.0   28.6  83.4    -5.4    561  2.9
 11000    9.6  49.3   205   10    5   9.2   5.0   28.5  83.2    -5.5    505  2.6
 10500   11.0  51.8   195   10    5   9.1   5.0   28.4  83.1    -5.6    450  2.3
 10250   11.7  53.1   195   10    5   9.1   5.0   28.3  83.0    -5.7    422  2.1
 10000   12.4  54.3   190    9    5   9.0   5.0   28.3  82.9    -5.8    395  2.0
  9750   13.0  55.4   190    9    5   9.0   5.0   28.2  82.8    -5.8    367  1.9
  9500   13.7  56.7   185    9    4   9.0   5.0   28.1  82.7    -5.9    340  1.7
  9250   14.4  57.9   185    8    4   9.1   5.0   28.1  82.6    -6.0    312  1.6
  9000   15.0  59.0   180    8    4   8.9   4.9   28.1  82.5    -6.0    285  1.4
  8750   15.7  60.3   175    8    4   9.5   5.2   28.0  82.4    -6.1    257  1.3
  8500   16.4  61.5   170    8    4   7.3   4.0   27.9  82.3    -6.2    230  1.2
  8250   16.8  62.2   165    9    4   4.8   2.7   27.6  81.7    -6.5    210  1.1
  8000   17.2  63.0   160    9    5   5.8   3.2   27.3  81.1    -6.9    191  1.0
  7750   17.6  63.7   155   11    6   4.2   2.3   26.9  80.5    -7.3    172  0.9
  7500   17.7  63.9   155   13    7  -2.2  -1.2   26.3  79.3    -7.9    162  0.8
  7250   17.3  63.1   150   15    8  -5.1  -2.8   25.2  77.3    -9.0    165  0.8
  7000   16.9  62.4   150   18    9  -5.9  -3.2   24.1  75.3   -10.1    169  0.9
  6750   16.6  61.9   150   18    9   1.9   1.0   23.0  73.4   -11.2    171  0.9
  6500   17.2  63.0   145   17    9   9.4   5.2   22.9  73.1   -11.4    146  0.7
  6250   17.8  64.0   145   17    9   7.4   4.1   22.7  72.9   -11.6    121  0.6
  6000   18.4  65.1   140   17    9   7.9   4.3   22.6  72.6   -11.7     97  0.5
  5750   18.8  65.8   135   16    8   2.5   1.4   22.3  72.1   -12.1     76  0.4
  5500   18.8  65.8   130   14    7   0.7   0.4   21.6  70.8   -12.8     69  0.3
  5250   18.8  65.8   125   12    6  -4.4  -2.4   20.8  69.5   -13.6     62  0.3
  5000   17.8  64.0   115   11    6 -23.4 -12.9   19.1  66.4   -15.4     85  0.4

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

           05/25/2018 at 0900 MDT          |       05/25/2018 at 1200 MDT
                                           |
K index... +7.3  LI... +4.3                | K index... +2.7  LI... +4.6
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  250  20 10   2.2   1.2 | -62.1 -79.8  250  21 11   2.1   1.1
 45000 -58.7 -73.7  255  26 13   0.5   0.3 | -59.3 -74.7  255  27 14   0.5   0.3
 40000 -57.7 -71.9  265  30 15   5.1   2.8 | -58.3 -72.9  270  30 15   6.1   3.4
 38000 -53.8 -64.8  275  31 16   6.6   3.6 | -54.1 -65.4  270  32 16   7.0   3.8
 36000 -49.8 -57.6  285  34 17   6.6   3.6 | -49.9 -57.8  275  34 17   7.0   3.8
 34000 -45.3 -49.5  285  34 17   7.9   4.3 | -45.1 -49.2  275  34 18   8.2   4.5
 32000 -40.6 -41.1  285  33 17   7.9   4.3 | -40.2 -40.4  275  34 17   8.3   4.5
 30000 -36.1 -33.0  280  30 15   7.2   3.9 | -34.7 -30.5  275  33 17   8.2   4.5
 29000 -33.4 -28.1  275  27 14   7.2   3.9 | -32.2 -26.0  275  32 16   8.2   4.5
 28000 -31.3 -24.3  270  24 13   7.3   4.0 | -29.8 -21.6  275  31 16   8.0   4.4
 27000 -29.0 -20.2  265  24 12   7.8   4.3 | -27.4 -17.3  275  29 15   7.8   4.3
 26000 -26.6 -15.9  265  24 12   7.8   4.3 | -25.1 -13.2  270  27 14   7.8   4.3
 25000 -24.3 -11.7  260  24 12   7.8   4.3 | -22.8  -9.0  270  25 13   7.8   4.3
 24000 -21.8  -7.2  260  23 12   8.2   4.5 | -20.4  -4.7  265  24 12   7.8   4.3
 23000 -19.4  -2.9  255  23 12   8.2   4.5 | -18.1  -0.6  255  23 12   7.8   4.3
 22000 -16.9   1.6  255  23 12   8.3   4.5 | -15.7   3.7  245  22 11   7.8   4.3
 21000 -14.6   5.7  250  23 12   7.4   4.1 | -13.5   7.7  240  23 12   7.4   4.0
 20000 -12.4   9.7  245  23 12   7.5   4.1 | -11.3  11.7  235  23 12   7.4   4.0
 19500 -11.3  11.7  245  24 12   7.5   4.1 | -10.2  13.6  230  24 12   7.4   4.1
 19000 -10.2  13.6  240  23 12   6.8   3.7 |  -9.1  15.6  230  24 13   6.7   3.7
 18500  -9.2  15.4  240  23 12   6.7   3.7 |  -8.1  17.4  225  24 13   6.6   3.6
 18000  -8.3  17.1  235  22 11   6.7   3.7 |  -7.1  19.2  225  24 13   6.6   3.6
 17500  -7.3  18.9  230  20 11   6.7   3.7 |  -6.2  20.8  225  24 13   6.6   3.6
 17000  -6.3  20.7  225  19 10   6.8   3.7 |  -5.2  22.6  225  25 13   6.6   3.6
 16500  -5.3  22.5  220  18  9   6.4   3.5 |  -4.2  24.4  220  25 13   6.9   3.8
 16000  -4.4  24.1  210  17  9   6.4   3.5 |  -3.1  26.4  220  24 13   7.0   3.8
 15500  -3.5  25.7  205  17  9   7.6   4.1 |  -2.1  28.2  215  24 13   6.8   3.7
 15000  -2.2  28.0  205  16  8   8.8   4.8 |  -1.2  29.8  215  23 12   6.5   3.6
 14500  -0.9  30.4  205  16  8   8.9   4.9 |  -0.3  31.5  210  22 12   6.7   3.7
 14000   1.0  33.8  205  15  8   8.7   4.8 |   1.2  34.2  205  20 10   7.3   4.0
 13500   2.3  36.1  205  14  7   8.9   4.9 |   2.2  36.0  205  19 10   8.1   4.5
 13000   3.7  38.7  210  13  7   8.9   4.9 |   3.6  38.5  200  18  9   8.8   4.9
 12500   5.0  41.0  210  13  6   8.7   4.8 |   4.9  40.8  195  16  8   8.9   4.9
 12000   6.2  43.2  220  12  6   8.4   4.6 |   6.2  43.2  195  15  8   8.9   4.9
 11500   7.5  45.5  225  11  6   8.5   4.7 |   7.5  45.5  190  14  7   9.1   5.0
 11000   8.8  47.8  230  11  6   8.5   4.7 |   9.0  48.2  190  13  7   9.2   5.1
 10500  10.1  50.2  235  10  5   4.2   2.3 |  10.4  50.7  185  12  6   5.6   3.1
 10250  10.3  50.5  235  10  5   5.3   2.9 |  10.6  51.1  185  11  6   6.0   3.3
 10000  11.1  52.0  235  10  5  11.8   6.5 |  11.4  52.5  185  11  5  11.2   6.1
  9750  11.9  53.4  235   9  5  10.7   5.9 |  12.2  54.0  185  10  5  10.1   5.6
  9500  12.6  54.7  235   9  4   8.4   4.6 |  12.9  55.2  180   9  5   9.1   5.0
  9250  13.1  55.6  235   8  4   5.7   3.1 |  13.5  56.3  180   9  5   8.5   4.6
  9000  13.6  56.5  230   8  4   7.7   4.2 |  14.2  57.6  180   9  4  10.2   5.6
  8750  14.2  57.6  225   7  4   8.4   4.6 |  15.0  59.0  180   8  4  10.3   5.7
  8500  14.8  58.6  220   7  3   7.6   4.1 |  15.7  60.3  180   8  4  10.3   5.7
  8250  15.4  59.7  210   6  3   6.8   3.8 |  16.5  61.7  180   8  4  10.4   5.7
  8000  15.9  60.6  195   6  3   7.1   3.9 |  17.3  63.1  180   8  4   9.9   5.4
  7750  16.4  61.5  185   7  3   7.0   3.8 |  18.0  64.4  180   8  4   9.6   5.3
  7500  16.9  62.4  175   7  4   5.6   3.1 |  18.8  65.8  180   8  4  10.1   5.5
  7250  17.3  63.1  175   8  4   5.0   2.8 |  19.5  67.1  185   7  4  10.5   5.7
  7000  17.6  63.7  170   9  5   4.4   2.4 |  20.3  68.5  185   7  4  10.0   5.5
  6750  17.9  64.2  170  10  5   3.4   1.9 |  21.0  69.8  185   7  4  10.3   5.6
  6500  18.1  64.6  165   9  5   3.9   2.2 |  21.9  71.4  185   7  4  11.1   6.1
  6250  18.4  65.1  165   8  4   4.5   2.5 |  22.7  72.9  185   7  4  12.2   6.7
  6000  18.7  65.7  160   8  4   3.1   1.7 |  23.6  74.5  185   7  3   9.2   5.0
  5750  19.0  66.2  160   6  3   7.5   4.1 |  24.2  75.6  185   7  3  12.0   6.6
  5500  19.8  67.6  155   6  3  13.1   7.2 |  25.4  77.7  185   6  3  18.3  10.0
  5250  20.6  69.1  155   6  3   8.8   4.8 |  26.7  80.1  190   6  3  13.3   7.3
  5000     M     M    M   M  M     M     M |     M     M    M   M  M     M     M

           05/25/2018 at 1500 MDT          |       05/25/2018 at 1800 MDT
                                           |
K index... +6.8  LI... +4.3                | K index... +2.0  LI... +3.7
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 -61.9 -79.4  250  26 13   1.6   0.9 | -62.4 -80.3  245  27 14   1.1   0.6
 45000 -59.8 -75.6  250  35 18   0.3   0.2 | -60.7 -77.3  250  40 21   0.9   0.5
 40000 -59.0 -74.2  265  31 16   6.8   3.8 | -59.1 -74.4  275  42 22   7.1   3.9
 38000 -54.6 -66.3  265  32 17   7.3   4.0 | -54.6 -66.3  265  37 19   7.4   4.0
 36000 -50.2 -58.4  260  34 18   7.3   4.0 | -50.2 -58.4  250  33 17   7.4   4.0
 34000 -45.4 -49.7  260  33 17   8.3   4.6 | -45.4 -49.7  245  33 17   8.3   4.6
 32000 -40.4 -40.7  265  32 17   8.4   4.6 | -40.4 -40.7  245  32 17   8.4   4.6
 30000 -34.6 -30.3  265  31 16   8.8   4.8 | -35.2 -31.4  250  32 17   8.8   4.8
 29000 -31.9 -25.4  265  31 16   8.8   4.8 | -31.9 -25.4  250  32 16   8.8   4.8
 28000 -29.3 -20.7  260  30 16   8.4   4.6 | -29.3 -20.7  250  32 16   8.4   4.6
 27000 -26.9 -16.4  260  30 15   8.0   4.4 | -26.9 -16.4  250  31 16   8.0   4.4
 26000 -24.5 -12.1  260  29 15   8.0   4.4 | -24.5 -12.1  245  30 16   8.0   4.4
 25000 -22.1  -7.8  255  29 15   7.9   4.4 | -22.1  -7.8  245  30 15   8.0   4.4
 24000 -19.7  -3.5  255  28 14   8.3   4.5 | -19.7  -3.5  245  29 15   8.1   4.4
 23000 -17.2   1.0  250  27 14   8.3   4.6 | -17.3   0.9  240  28 15   8.1   4.4
 22000 -14.8   5.4  245  27 14   8.3   4.5 | -14.9   5.2  235  28 14   8.1   4.4
 21000 -12.5   9.5  240  26 14   7.3   4.0 | -12.5   9.5  235  27 14   7.7   4.2
 20000 -10.3  13.5  240  26 14   7.4   4.0 | -10.3  13.5  230  27 14   7.7   4.2
 19500  -9.2  15.4  235  26 14   7.5   4.1 |  -9.1  15.6  230  27 14   7.9   4.3
 19000  -8.2  17.2  235  26 14   5.1   2.8 |  -8.0  17.6  230  26 14   6.2   3.4
 18500  -7.5  18.5  230  27 14   4.8   2.6 |  -7.1  19.2  230  26 13   6.0   3.3
 18000  -6.8  19.8  225  27 14   5.0   2.7 |  -6.3  20.7  225  26 13   6.1   3.3
 17500  -5.9  21.4  225  27 14   6.3   3.4 |  -5.3  22.5  225  25 13   6.5   3.5
 17000  -5.0  23.0  220  27 14   6.1   3.4 |  -4.4  24.1  220  24 12   6.3   3.4
 16500  -4.0  24.8  215  26 14   8.0   4.4 |  -3.3  26.1  220  24 12   8.5   4.7
 16000  -2.9  26.8  215  26 13   8.2   4.5 |  -2.0  28.4  215  23 12   8.7   4.8
 15500  -1.7  28.9  215  25 13   8.4   4.6 |  -0.7  30.7  215  23 12   8.8   4.8
 15000  -0.4  31.3  210  24 12   8.6   4.7 |   0.6  33.1  215  22 11   8.9   4.9
 14500   0.9  33.6  210  23 12   8.6   4.7 |   1.9  35.4  210  22 11   9.0   4.9
 14000   2.8  37.0  205  22 11   8.9   4.9 |   4.0  39.2  210  21 11   9.2   5.1
 13500   4.2  39.6  205  21 11   8.8   4.8 |   5.3  41.5  210  21 11   9.0   4.9
 13000   5.5  41.9  200  19 10   8.7   4.8 |   6.7  44.1  210  20 10   8.8   4.8
 12500   6.7  44.1  200  18  9   8.8   4.8 |   8.0  46.4  205  19 10   8.8   4.8
 12000   8.1  46.6  200  16  8   9.0   4.9 |   9.3  48.7  205  17  9   8.8   4.8
 11500   9.4  48.9  200  15  8   9.1   5.0 |  10.6  51.1  205  16  8   8.6   4.7
 11000  10.8  51.4  200  14  7   9.3   5.1 |  11.8  53.2  205  14  7   7.7   4.2
 10500  12.2  54.0  200  13  7   6.7   3.7 |  12.9  55.2  205  12  6   9.8   5.4
 10250  12.7  54.9  200  12  6   7.7   4.3 |  13.7  56.7  205  12  6  10.5   5.8
 10000  13.5  56.3  200  12  6  11.9   6.5 |  14.4  57.9  210  11  6   8.3   4.5
  9750  14.3  57.7  200  12  6  11.3   6.2 |  15.0  59.0  210  10  5   9.0   4.9
  9500  15.1  59.2  200  12  6   9.7   5.3 |  15.7  60.3  215  10  5   8.4   4.6
  9250  15.8  60.4  200  12  6   9.0   4.9 |  16.3  61.3  215   9  5   9.0   5.0
  9000  16.6  61.9  200  12  6  10.8   5.9 |  17.0  62.6  220   9  5  10.0   5.5
  8750  17.4  63.3  200  11  6  10.8   5.9 |  17.8  64.0  220   9  4   9.8   5.4
  8500  18.1  64.6  200  11  6  10.5   5.8 |  18.5  65.3  225   8  4   9.9   5.4
  8250  18.9  66.0  200  11  6  10.1   5.6 |  19.3  66.7  225   8  4   9.9   5.5
  8000  19.7  67.5  200  11  6   9.8   5.4 |  20.0  68.0  230   8  4   9.6   5.3
  7750  20.4  68.7  200  11  6   9.6   5.2 |  20.7  69.3  230   8  4   9.2   5.1
  7500  21.1  70.0  200  11  5  10.0   5.5 |  21.4  70.5  230   8  4   9.9   5.4
  7250  21.9  71.4  200  10  5  10.5   5.8 |  22.2  72.0  235   8  4  10.9   6.0
  7000  22.7  72.9  200  10  5   9.9   5.4 |  23.0  73.4  235   8  4   9.8   5.4
  6750  23.4  74.1  200  10  5   9.7   5.3 |  23.6  74.5  235   8  4   8.8   4.8
  6500  24.2  75.6  200  10  5  10.8   5.9 |  24.4  75.9  235   7  4  10.5   5.7
  6250  25.0  77.0  200  10  5  11.9   6.5 |  25.2  77.4  240   7  4  11.7   6.4
  6000  25.9  78.6  200   9  5   9.9   5.4 |  26.1  79.0  240   7  4  10.7   5.9
  5750  26.6  79.9  200   9  5  12.2   6.7 |  26.8  80.2  240   7  4  10.0   5.5
  5500  27.8  82.0  205   9  4  17.6   9.7 |  27.6  81.7  240   7  4  10.6   5.8
  5250  29.0  84.2  205   9  4  16.1   8.8 |  28.4  83.1  245   7  4  11.0   6.0
  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.