Soaring Guidance
Issued by NWS Grand Junction, CO

Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9
000
UXUS97 KGJT 201233
SRGGJT

Soaring Forecast
National Weather Service Grand Junction, Colorado
0633 MDT Friday, October 20, 2017

This forecast is for Friday, October 20, 2017:

If the trigger temperature of 71.7 F/22.1 C is reached...then
   Thermal Soaring Index....................... Excellent
   Maximum rate of lift........................ 994 ft/min (5.1 m/s)
   Maximum height of thermals.................. 13590 ft MSL (8751 ft AGL)

Forecast maximum temperature................... 74.0 F/23.8 C
Time of trigger temperature.................... 1315 MDT
Time of overdevelopment........................ 1800 MDT
Middle/high clouds during soaring window....... None
Surface winds during soaring window............ 20 mph or less
Height of the -3 thermal index................. 7473 ft MSL (2634 ft AGL)
Thermal soaring outlook for Saturday 10/21..... Good

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

Remarks...

Sunrise/Sunset.................... 07:29:18 / 18:29:22 MDT
Total possible sunshine........... 11 hr 0 min 4 sec (660 min 4 sec)
Altitude of sun at 12:58:55 MDT... 40.29 degrees

Upper air data from rawinsonde observation taken on 10/20/2017 at 0600 MDT

Freezing level.................. 12549 ft MSL (7710 ft AGL)
Convective condensation level... 14355 ft MSL (9516 ft AGL)
Lifted condensation level....... 14073 ft MSL (9234 ft AGL)
Lifted index.................... +1.0
K index......................... +25.4

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  -63.2 -81.8   260   31   16  -5.9  -3.2   93.4 200.1    40.1      M    M
 45000  -64.6 -84.3   300   22   11   5.5   3.0   65.2 149.3    25.8      M    M
 40000  -56.7 -70.1   310   36   18  -0.9  -0.5   54.7 130.4    20.7      M    M
 38000  -52.4 -62.3   310   43   22   8.5   4.7   52.4 126.3    19.7      M    M
 36000  -48.8 -55.8   315   40   21   7.3   4.0   49.1 120.4    18.0      M    M
 34000  -44.0 -47.2   315   38   20   8.9   4.9   47.5 117.5    17.3      M    M
 32000  -39.3 -38.7   310   39   20   6.5   3.6   46.0 114.9    16.6      M    M
 30000  -36.4 -33.5   280   22   11   3.7   2.0   41.1 106.0    13.4      M    M
 29000  -35.3 -31.5   285   20   10   6.1   3.3   38.8 101.8    11.8      M    M
 28000  -32.8 -27.0   290   19   10   8.4   4.6   38.2 100.8    11.5      M    M
 27000  -30.6 -23.1   275   20   10   3.8   2.1   37.2  99.0    10.8      M    M
 26000  -28.5 -19.3   260   23   12   8.4   4.6   36.3  97.3    10.2      M    M
 25000  -26.0 -14.8   250   26   13   8.4   4.6   35.8  96.4     9.9      M    M
 24000  -23.8 -10.8   255   25   13   4.9   2.7   34.9  94.9     9.3      M    M
 23000  -21.5  -6.7   255   27   14   8.9   4.9   34.1  93.4     8.7      M    M
 22000  -18.9  -2.0   260   29   15   9.2   5.0   33.8  92.9     8.5      M    M
 21000  -17.3   0.9   260   31   16   2.1   1.1   32.4  90.2     7.3      M    M
 20000  -16.5   2.3   260   33   17   9.8   5.4   29.8  85.7     5.2      M    M
 19500  -15.7   3.7   245   30   16   8.3   4.6   29.1  84.4     4.6      M    M
 19000  -14.6   5.7   225   31   16   3.0   1.6   28.8  83.9     4.4      M    M
 18500  -13.7   7.3   220   30   16   9.6   5.3   28.1  82.6     3.8      M    M
 18000  -12.4   9.7   220   31   16   9.0   4.9   28.0  82.5     3.7      M    M
 17500  -11.3  11.7   215   33   17   6.9   3.8   27.6  81.7     3.3      M    M
 17000   -9.6  14.7   215   33   17   7.9   4.3   27.1  80.8     2.9      M    M
 16500   -8.4  16.9   215   31   16   7.8   4.3   26.8  80.2     2.6      M    M
 16000   -7.3  18.9   215   29   15   7.3   4.0   26.5  79.6     2.3      M    M
 15500   -6.5  20.3   215   30   15   5.9   3.3   25.8  78.4     1.6      M    M
 15000   -5.4  22.3   215   30   15   6.9   3.8   25.3  77.6     1.2      M    M
 14500   -4.4  24.1   225   28   15   7.0   3.9   24.9  76.8     0.8      M    M
 14000   -3.4  25.9   235   28   14   7.0   3.8   24.4  75.9     0.3      M    M
 13500   -2.4  27.7   235   28   14   7.8   4.3   24.0  75.1    -0.2    781  4.0
 13000   -1.1  30.0   240   28   14   9.2   5.1   23.8  74.9    -0.3    727  3.7
 12500    0.3  32.5   240   28   14   9.2   5.0   23.7  74.7    -0.4    671  3.4
 12000    1.6  34.9   240   28   14   9.2   5.0   23.7  74.6    -0.4    615  3.1
 11500    3.0  37.4   240   26   14   9.2   5.0   23.6  74.4    -0.5    559  2.8
 11000    4.4  39.9   245   25   13   9.2   5.0   23.5  74.3    -0.6    504  2.6
 10500    5.7  42.3   235   25   13   9.2   5.0   23.4  74.1    -0.7    448  2.3
 10250    6.4  43.5   235   25   13   9.2   5.1   23.3  74.0    -0.8    420  2.1
 10000    7.1  44.8   230   25   13   9.0   4.9   23.3  73.9    -0.9    392  2.0
  9750    7.7  45.9   225   25   13   8.7   4.8   23.2  73.8    -0.9    365  1.9
  9500    8.4  47.1   225   24   13   8.8   4.8   23.1  73.6    -1.0    338  1.7
  9250    9.0  48.2   225   24   12   8.8   4.8   23.1  73.5    -1.1    312  1.6
  9000    9.7  49.5   220   24   12   8.7   4.8   23.0  73.4    -1.2    285  1.4
  8750   10.3  50.5   215   25   13   8.9   4.9   22.9  73.2    -1.2    258  1.3
  8500   11.0  51.8   215   26   13   8.3   4.5   22.8  73.1    -1.3    231  1.2
  8250   11.5  52.7   210   27   14   5.0   2.8   22.6  72.7    -1.5    208  1.1
  8000   11.8  53.2   210   28   14   3.5   1.9   22.2  71.9    -2.0    193  1.0
  7750   12.0  53.6   210   26   14   3.5   1.9   21.7  71.0    -2.5    177  0.9
  7500   12.3  54.1   210   24   13   4.9   2.7   21.2  70.2    -2.9    162  0.8
  7250   12.8  55.0   210   22   12   7.5   4.1   21.0  69.8    -3.2    140  0.7
  7000   13.4  56.1   210   20   11   7.8   4.3   20.8  69.5    -3.3    115  0.6
  6750   13.9  57.0   210   18    9   7.7   4.2   20.7  69.2    -3.5     91  0.5
  6500   14.5  58.1   205   15    8   7.8   4.3   20.5  69.0    -3.6     66  0.3
  6250   15.1  59.2   200   13    7   7.7   4.2   20.4  68.7    -3.8     41  0.2
  6000   15.7  60.3   195   11    5   7.8   4.3   20.2  68.4    -4.0     16  0.1
  5750   16.3  61.3   190    9    4   7.4   4.0   20.1  68.2    -4.1      M    M
  5500   16.8  62.2   175    7    4   9.1   5.0   19.9  67.9    -4.3      M    M
  5250   17.4  63.3   160    6    3   0.6   0.3   19.7  67.5    -4.5      M    M
  5000   16.7  62.1   135    5    3 -18.6 -10.2   18.3  64.9    -5.9      M    M

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

           10/20/2017 at 0900 MDT          |       10/20/2017 at 1200 MDT
                                           |
K index... +19.7  LI... +0.9               | K index... +9.7  LI... +0.1
CAPE... +2.2  CIN... -3.2                  | CAPE... +20.3  CIN... -9.0
                                           |
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 -62.1 -79.8  245  31 16  -0.8  -0.5 | -61.3 -78.3  240  39 20  -0.0  -0.0
 45000 -62.9 -81.2  240  30 16   3.0   1.7 | -61.1 -78.0  230  53 27   2.0   1.1
 40000 -58.3 -72.9  270  49 25   2.4   1.3 | -58.2 -72.8  235  58 30   1.8   1.0
 38000 -54.0 -65.2  270  47 24   8.0   4.4 | -55.1 -67.2  235  58 30   6.2   3.4
 36000 -49.2 -56.6  270  42 22   8.0   4.4 | -51.4 -60.5  235  58 30   6.2   3.4
 34000 -44.4 -47.9  270  39 20   7.9   4.3 | -47.3 -53.1  240  56 29   8.0   4.4
 32000 -39.7 -39.5  270  36 18   7.9   4.3 | -42.5 -44.5  245  55 28   8.0   4.4
 30000 -35.2 -31.4  270  32 17   6.9   3.8 | -37.7 -35.9  250  54 28   8.1   4.4
 29000 -33.1 -27.6  265  31 16   7.6   3.8 | -35.3 -31.5  255  54 28   8.1   4.4
 28000 -30.5 -22.9  265  29 15   6.9   3.8 | -32.9 -27.2  255  54 28   8.1   4.4
 27000 -28.5 -19.3  260  28 14   6.1   3.4 | -29.9 -21.8  260  53 27   7.9   4.3
 26000 -26.7 -16.1  255  29 15   6.1   3.4 | -27.5 -17.5  255  51 26   7.9   4.3
 25000 -24.8 -12.6  250  30 15   6.1   3.4 | -25.1 -13.2  255  48 25   7.9   4.4
 24000 -23.0  -9.4  250  31 16   5.4   3.0 | -22.8  -9.0  255  46 24   7.3   4.0
 23000 -21.4  -6.5  250  33 17   5.4   3.0 | -20.6  -5.1  250  45 23   7.3   4.0
 22000 -19.8  -3.6  250  34 18   5.4   3.0 | -18.5  -1.3  245  44 23   7.3   4.0
 21000 -18.0  -0.4  250  36 18   7.5   4.1 | -16.5   2.3  245  43 22   4.1   2.3
 20000 -15.9   3.4  245  36 18   7.3   4.0 | -15.2   4.6  240  43 22   4.5   2.5
 19500 -14.8   5.4  245  36 18   7.3   4.0 | -14.5   5.9  240  43 22   4.5   2.5
 19000 -13.7   7.3  245  36 18   7.4   4.1 | -13.8   7.2  240  43 22   4.5   2.5
 18500 -12.6   9.3  245  36 18   6.1   3.4 | -13.1   8.4  235  43 22   5.6   3.1
 18000 -11.8  10.8  245  36 19   5.9   3.2 | -12.2  10.0  240  44 22   6.0   3.3
 17500 -10.9  12.4  245  37 19   5.9   3.2 | -11.3  11.7  240  44 22   6.1   3.3
 17000 -10.1  13.8  240  37 19   5.8   3.2 | -10.4  13.3  240  44 23   6.2   3.4
 16500  -9.2  15.4  240  37 19   5.8   3.2 |  -9.5  14.9  240  44 23   6.2   3.4
 16000  -8.4  16.9  235  37 19   5.6   3.1 |  -8.6  16.5  240  44 23   6.1   3.4
 15500  -7.6  18.3  235  37 19   5.7   3.1 |  -7.7  18.1  240  44 23   6.2   3.4
 15000  -6.8  19.8  230  37 19   6.5   3.6 |  -6.8  19.8  240  44 23   6.3   3.5
 14500  -5.8  21.6  230  37 19   7.0   3.9 |  -5.8  21.6  240  43 22   6.5   3.6
 14000  -4.8  23.4  230  37 19   7.4   4.1 |  -4.9  23.2  240  43 22   6.7   3.7
 13500  -3.2  26.2  230  35 18   8.0   4.4 |  -3.9  25.0  240  42 22   7.4   4.0
 13000  -2.0  28.4  230  34 18   9.2   5.0 |  -2.4  27.7  235  40 21   8.0   4.4
 12500  -0.6  30.9  230  33 17   9.5   5.2 |  -1.2  29.8  235  39 20   8.4   4.6
 12000   0.8  33.4  230  32 17   8.8   4.8 |  -0.1  31.8  235  37 19   9.1   5.0
 11500   2.0  35.6  230  31 16   8.3   4.6 |   1.3  34.3  235  37 19   9.4   5.2
 11000   3.2  37.8  230  30 15   8.6   4.7 |   2.7  36.9  230  37 19   9.1   5.0
 10500   4.5  40.1  230  28 14   8.6   4.7 |   4.0  39.2  230  36 18   8.7   4.8
 10250   5.2  41.4  230  27 14  10.3   5.6 |   4.6  40.3  230  35 18   9.6   5.3
 10000   6.0  42.8  230  26 13   9.8   5.4 |   5.3  41.5  230  34 18   9.6   5.3
  9750   6.6  43.9  230  25 13   8.1   4.4 |   6.0  42.8  230  33 17   8.8   4.8
  9500   7.3  45.1  230  23 12   8.8   4.8 |   6.7  44.1  225  31 16   9.3   5.1
  9250   7.9  46.2  230  21 11   7.8   4.3 |   7.3  45.1  225  29 15   8.0   4.4
  9000   8.4  47.1  235  21 11   7.2   4.0 |   7.9  46.2  225  28 15   8.1   4.5
  8750   9.0  48.2  230  20 10   7.6   4.2 |   8.5  47.3  225  26 14   9.6   5.3
  8500   9.5  49.1  230  19 10   7.3   4.0 |   9.2  48.6  220  24 13   8.6   4.7
  8250  10.1  50.2  230  18  9   8.1   4.4 |   9.9  49.8  220  23 12  11.2   6.1
  8000  10.7  51.3  230  18  9   6.8   3.8 |  10.8  51.4  220  22 11  11.0   6.0
  7750  11.1  52.0  230  18  9   5.0   2.7 |  11.5  52.7  220  21 11   8.4   4.6
  7500  11.4  52.5  225  18  9   5.9   3.2 |  12.1  53.8  220  21 11   8.9   4.9
  7250  11.8  53.2  225  19 10   4.0   2.2 |  12.8  55.0  220  21 11   9.6   5.3
  7000  12.0  53.6  215  19 10   1.5   0.8 |  13.6  56.5  215  20 10  10.5   5.7
  6750  12.1  53.8  205  18  9   1.2   0.7 |  14.3  57.7  215  20 10   9.9   5.4
  6500  12.1  53.8  195  18  9  -0.1  -0.0 |  15.0  59.0  215  19 10   9.9   5.4
  6250  12.0  53.6  190  16  8  -4.8  -2.7 |  15.8  60.4  215  19 10  10.5   5.8
  6000  11.5  52.7  180  14  7  -6.5  -3.6 |  16.6  61.9  215  18  9  10.9   6.0
  5750  11.1  52.0  170  11  5  -4.9  -2.7 |  17.4  63.3  215  17  9   9.8   5.4
  5500  10.9  51.6  150   7  4  -0.6  -0.3 |  18.1  64.6  215  15  8  11.2   6.2
  5250  11.1  52.0  150   7  3   7.7   4.2 |  19.1  66.4  215  15  8  15.6   8.6
  5000     M     M    M   M  M     M     M |     M     M    M   M  M     M     M

           10/20/2017 at 1500 MDT          |       10/20/2017 at 1800 MDT
                                           |
K index... +22.3  LI... +0.5               | K index... +25.1  LI... -1.6
CAPE... +11.3  CIN... -3.4                 | CAPE... +62.4  CIN... -29.9
                                           |
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 -58.6 -73.5  240  42 22   1.5   0.8 | -58.0 -72.4  240  42 22   1.0   0.5
 45000 -56.5 -69.7  240  61 31  -0.6  -0.3 | -56.5 -69.7  255  55 28  -0.1  -0.0
 40000 -57.2 -71.0  235  49 25  -0.4  -0.2 | -56.5 -69.7  245  63 33  -0.0  -0.0
 38000 -55.5 -67.9  240  52 27   4.6   2.5 | -55.5 -67.9  245  69 35   3.1   1.7
 36000 -52.7 -62.9  250  60 31   4.6   2.5 | -53.6 -64.5  250  76 39   3.1   1.7
 34000 -49.4 -56.9  255  67 34   7.9   4.3 | -51.1 -60.0  250  80 41   8.8   4.8
 32000 -44.0 -47.2  250  67 34   8.0   4.4 | -45.3 -49.5  240  71 36   8.5   4.7
 30000 -39.0 -38.2  250  66 34   8.7   4.8 | -40.3 -40.5  235  67 35   8.4   4.6
 29000 -36.4 -33.5  250  65 33   8.7   4.8 | -37.8 -36.0  240  69 36   8.3   4.6
 28000 -33.8 -28.8  250  64 33   8.7   4.8 | -35.3 -31.5  240  71 37   8.3   4.6
 27000 -31.3 -24.3  250  63 32   7.4   4.0 | -32.8 -27.0  240  74 38   7.5   4.1
 26000 -29.1 -20.4  245  63 32   7.4   4.1 | -30.7 -23.3  245  72 37   7.0   3.9
 25000 -26.9 -16.4  245  62 32   7.4   4.1 | -28.6 -19.5  245  71 36   7.0   3.9
 24000 -24.6 -12.3  245  62 32   7.4   4.0 | -26.5 -15.7  245  69 36   6.8   3.7
 23000 -22.4  -8.3  245  61 31   7.3   4.0 | -24.8 -12.6  245  65 33   5.7   3.2
 22000 -20.2  -4.4  245  59 30   7.3   4.0 | -23.1  -9.6  245  60 31   5.8   3.2
 21000 -18.1  -0.6  245  57 29   6.0   3.3 | -21.3  -6.3  240  55 28   6.1   3.3
 20000 -16.4   2.5  245  55 28   5.7   3.1 | -19.5  -3.1  240  52 27   6.5   3.6
 19500 -15.6   3.9  245  54 28   5.7   3.2 | -18.5  -1.3  235  51 26   6.5   3.6
 19000 -14.7   5.5  240  52 27   5.7   3.1 | -17.1   1.2  235  49 25   6.4   3.5
 18500 -13.9   7.0  240  51 26   5.2   2.8 | -16.1   3.0  230  47 24   8.7   4.8
 18000 -13.2   8.2  240  50 26   4.6   2.5 | -14.8   5.4  230  45 23   9.0   4.9
 17500 -12.6   9.3  240  48 25   4.4   2.4 | -13.5   7.7  230  43 22   9.0   4.9
 17000 -11.8  10.8  240  47 24   6.3   3.4 | -12.2  10.0  230  42 22   8.9   4.9
 16500 -10.9  12.4  240  46 24   6.1   3.4 | -10.9  12.4  230  41 21   9.0   4.9
 16000 -10.0  14.0  240  45 23   7.2   4.0 |  -9.6  14.7  230  40 21   8.0   4.4
 15500  -8.9  16.0  240  44 22   7.7   4.3 |  -8.4  16.9  230  39 20   8.0   4.4
 15000  -7.2  19.0  235  41 21   9.0   4.9 |  -7.2  19.0  230  38 19   8.8   4.8
 14500  -5.9  21.4  235  39 20   9.0   4.9 |  -5.9  21.4  230  37 19   9.1   5.0
 14000  -4.5  23.9  235  37 19   9.4   5.2 |  -4.5  23.9  225  36 19   9.3   5.1
 13500  -3.1  26.4  230  36 18   9.5   5.2 |  -3.1  26.4  225  35 18   9.5   5.2
 13000  -1.7  28.9  230  35 18   9.5   5.2 |  -1.7  28.9  230  34 18   9.4   5.2
 12500  -0.3  31.5  230  33 17   9.4   5.2 |  -0.3  31.5  230  34 17   9.1   5.0
 12000   1.1  34.0  230  31 16   9.4   5.2 |   1.0  33.8  230  33 17   9.1   5.0
 11500   2.5  36.5  230  29 15   9.5   5.2 |   2.4  36.3  230  32 17   8.9   4.9
 11000   3.9  39.0  230  28 14   9.6   5.3 |   3.7  38.7  230  31 16   9.0   4.9
 10500   5.4  41.7  230  27 14  10.0   5.5 |   5.1  41.2  235  30 16   9.7   5.3
 10250   6.1  43.0  230  27 14   9.3   5.1 |   5.8  42.4  235  30 15   9.2   5.0
 10000   6.8  44.2  230  26 13   9.6   5.2 |   6.5  43.7  235  29 15   8.8   4.8
  9750   7.6  45.7  230  26 13  10.2   5.6 |   7.2  45.0  235  29 15   9.2   5.0
  9500   8.3  46.9  230  25 13  10.5   5.8 |   7.8  46.0  235  28 14   9.4   5.2
  9250   9.1  48.4  230  25 13   9.1   5.0 |   8.5  47.3  235  27 14   9.0   4.9
  9000   9.7  49.5  230  24 13   8.8   4.8 |   9.1  48.4  235  26 14   7.5   4.1
  8750  10.5  50.9  230  24 12  10.2   5.6 |   9.7  49.5  240  26 13   8.7   4.8
  8500  11.2  52.2  230  24 12   9.5   5.2 |  10.4  50.7  240  25 13  10.0   5.5
  8250  12.0  53.6  230  23 12  11.6   6.4 |  11.2  52.2  240  24 12  10.4   5.7
  8000  12.9  55.2  230  23 12  11.0   6.1 |  11.9  53.4  245  23 12   7.7   4.2
  7750  13.6  56.5  230  23 12   8.7   4.8 |  12.4  54.3  245  22 12   7.1   3.9
  7500  14.2  57.6  230  22 12   9.1   5.0 |  13.0  55.4  245  22 11   9.5   5.2
  7250  14.9  58.8  230  22 11   9.7   5.3 |  13.7  56.7  245  21 11   9.1   5.0
  7000  15.7  60.3  235  22 11  10.4   5.7 |  14.4  57.9  250  20 10   8.4   4.6
  6750  16.4  61.5  235  21 11   9.8   5.4 |  15.0  59.0  250  19 10   8.2   4.5
  6500  17.2  63.0  235  21 11   9.5   5.2 |  15.6  60.1  250  18  9   9.1   5.0
  6250  17.9  64.2  235  20 10  10.1   5.6 |  16.3  61.3  255  16  8   8.7   4.8
  6000  18.7  65.7  235  19 10  10.8   5.9 |  16.9  62.4  255  15  8   8.2   4.5
  5750  19.5  67.1  235  18  9  10.4   5.7 |  17.5  63.5  255  14  7   6.7   3.7
  5500  20.3  68.5  235  16  8  11.1   6.1 |  17.9  64.2  255  12  6   4.9   2.7
  5250  21.2  70.2  235  16  8  13.6   7.5 |     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



USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.