Soaring Guidance
Issued by NWS Grand Junction, CO

Home | Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7
000
UXUS97 KGJT 171236
SRGGJT

Soaring Forecast
National Weather Service Grand Junction, Colorado
0536 MST Friday, November 17, 2017

This forecast is for Friday, November 17, 2017:

If the trigger temperature of 63.8 F/17.7 C is reached...then
   Thermal Soaring Index....................... Poor
   Maximum rate of lift........................ 0 ft/min (0.0 m/s)
   Maximum height of thermals.................. 5072 ft MSL (233 ft AGL)

Forecast maximum temperature................... 61.0 F/16.6 C
Time of trigger temperature.................... 1300 MST
Time of overdevelopment........................ 1600 MST
Middle/high clouds during soaring window....... Broken/overcast opaque middle
Surface winds during soaring window............ Between 20 mph and 30 mph
Height of the -3 thermal index................. None
Thermal soaring outlook for Saturday 11/18..... Poor

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

Remarks...

Sunrise/Sunset.................... 06:59:57 / 16:58:19 MST
Total possible sunshine........... 9 hr 58 min 22 sec (598 min 22 sec)
Altitude of sun at 11:59:19 MST... 31.76 degrees

Upper air data from rawinsonde observation taken on 11/17/2017 at 0500 MST

Freezing level.................. 10963 ft MSL (6124 ft AGL)
Convective condensation level... 15537 ft MSL (10698 ft AGL)
Lifted condensation level....... 13020 ft MSL (8181 ft AGL)
Lifted index.................... +6.6
K index......................... +19.9

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  -62.6 -80.7   260   93   48  -0.6  -0.3   95.7 204.3    45.4      M    M
 45000  -58.5 -73.3   255  113   58   7.4   4.1   76.6 169.9    37.2      M    M
 40000  -58.3 -72.9   255  138   71   5.4   3.0   53.9 129.0    24.8      M    M
 38000  -54.6 -66.3   260  126   65   6.0   3.3   50.7 123.2    23.3      M    M
 36000  -53.1 -63.6   270  141   73   8.9   4.9   44.4 111.9    19.6      M    M
 34000  -48.3 -54.9   265  133   69   6.0   3.3   42.9 109.2    19.0      M    M
 32000  -42.7 -44.9   260  131   67   8.5   4.7   41.5 106.6    18.6      M    M
 30000  -38.3 -36.9   260  122   63   5.5   3.0   39.6 103.3    17.6      M    M
 29000  -36.6 -33.9   260  116   60   6.6   3.6   38.0 100.4    16.6      M    M
 28000  -34.5 -30.1   260  111   57   6.8   3.8   37.0  98.6    16.0      M    M
 27000  -32.4 -26.3   260  106   54   8.0   4.4   36.0  96.7    15.4      M    M
 26000  -30.0 -22.0   260  100   52   7.8   4.3   35.3  95.5    15.0      M    M
 25000  -28.1 -18.6   260   95   49   4.9   2.7   34.0  93.2    14.2      M    M
 24000  -26.4 -15.5   260   87   45   9.0   4.9   32.6  90.6    13.2      M    M
 23000  -24.0 -11.2   260   84   43   8.1   4.4   31.9  89.4    12.8      M    M
 22000  -21.7  -7.1   260   82   42   7.6   4.2   31.2  88.1    12.3      M    M
 21000  -19.3  -2.7   255   79   41   8.3   4.5   30.6  87.2    11.9      M    M
 20000  -18.0  -0.4   255   76   39   4.2   2.3   28.8  83.8    10.5      M    M
 19500  -17.4   0.7   255   72   37   4.2   2.3   27.8  82.1     9.7      M    M
 19000  -16.7   1.9   255   67   35   3.9   2.2   26.8  80.3     8.9      M    M
 18500  -16.1   3.0   255   62   32   3.4   1.9   25.8  78.5     8.1      M    M
 18000  -15.3   4.5   255   61   32   7.8   4.3   25.1  77.2     7.5      M    M
 17500  -14.2   6.4   255   60   31   7.4   4.0   24.7  76.4     7.1      M    M
 17000  -12.6   9.3   255   59   31   7.3   4.0   24.0  75.3     6.6      M    M
 16500  -11.5  11.3   255   59   30   8.1   4.4   23.7  74.6     6.3      M    M
 16000  -10.3  13.5   255   57   30   8.2   4.5   23.4  74.2     6.1      M    M
 15500   -9.1  15.6   255   54   28   6.0   3.3   23.0  73.5     5.8      M    M
 15000   -8.4  16.9   255   52   27   5.4   3.0   22.3  72.1     5.1      M    M
 14500   -7.6  18.3   255   49   25   6.3   3.5   21.7  71.0     4.5      M    M
 14000   -6.7  19.9   255   46   24   6.2   3.4   21.1  70.0     4.0      M    M
 13500   -5.8  21.6   260   44   23   6.3   3.4   20.5  68.9     3.5      M    M
 13000   -4.9  23.2   260   43   22   6.3   3.4   19.9  67.9     2.9      M    M
 12500   -3.7  25.3   255   42   22   8.5   4.7   19.6  67.2     2.6      M    M
 12000   -2.5  27.5   255   42   22   8.3   4.6   19.3  66.8     2.4      M    M
 11500   -1.3  29.7   250   40   20   8.3   4.6   19.1  66.4     2.2      M    M
 11000   -0.1  31.8   250   38   19   8.3   4.6   18.9  65.9     2.0      M    M
 10500    1.3  34.3   245   36   18   9.4   5.2   18.7  65.7     1.9      M    M
 10250    2.0  35.6   245   35   18   9.4   5.1   18.7  65.7     1.8      M    M
 10000    2.7  36.9   240   34   18   9.1   5.0   18.7  65.6     1.8      M    M
  9750    3.3  37.9   240   33   17   8.7   4.8   18.6  65.5     1.7      M    M
  9500    4.0  39.2   240   32   16   8.7   4.8   18.5  65.3     1.7      M    M
  9250    4.7  40.5   235   30   16   8.7   4.8   18.4  65.2     1.6      M    M
  9000    5.3  41.5   235   29   15   8.8   4.8   18.4  65.1     1.6      M    M
  8750    6.0  42.8   235   29   15   9.2   5.0   18.3  64.9     1.5      M    M
  8500    6.7  44.1   235   28   15   9.4   5.2   18.3  64.9     1.5      M    M
  8250    7.4  45.3   230   28   15   9.4   5.1   18.3  64.9     1.5      M    M
  8000    8.1  46.6   230   28   14   9.4   5.2   18.2  64.8     1.5      M    M
  7750    8.8  47.8   230   28   14   9.4   5.1   18.2  64.8     1.4      M    M
  7500    9.5  49.1   230   28   14   9.4   5.1   18.2  64.7     1.4      M    M
  7250   10.2  50.4   230   27   14   9.4   5.1   18.2  64.7     1.4      M    M
  7000   10.9  51.6   230   27   14   9.4   5.1   18.1  64.7     1.4      M    M
  6750   11.6  52.9   230   25   13   9.4   5.1   18.1  64.6     1.3      M    M
  6500   12.3  54.1   235   22   11   9.4   5.1   18.1  64.5     1.3      M    M
  6250   13.0  55.4   235   19   10   9.4   5.2   18.0  64.5     1.3      M    M
  6000   13.7  56.7   240   17    9   9.3   5.1   18.0  64.4     1.3      M    M
  5750   14.4  57.9   240   13    7   9.5   5.2   18.0  64.4     1.2      M    M
  5500   15.1  59.2   230   10    5   8.8   4.8   17.9  64.3     1.2      M    M
  5250   15.6  60.1   220    6    3   3.4   1.9   17.7  63.9     0.9      M    M
  5000   15.5  59.9   185    3    2  -7.7  -4.3   16.8  62.3     0.1      M    M

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

           11/17/2017 at 0800 MST          |       11/17/2017 at 1100 MST
                                           |
K index... +26.4  LI... +0.4               | K index... +20.9  LI... -1.1
CAPE... +0.3  CIN... -1.1                  | CAPE... +89.8  CIN... -17.2
                                           |
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 -63.8 -82.8  265  86 44   2.8   1.5 | -62.6 -80.7  265  89 46   2.3   1.3
 45000 -59.7 -75.5  265 108 56   1.5   0.8 | -59.1 -74.4  265 106 55   2.1   1.2
 40000 -57.3 -71.1  265 128 66   1.5   0.8 | -56.0 -68.8  260 128 66   2.1   1.1
 38000 -54.7 -66.5  265 135 70   6.2   3.4 | -53.5 -64.3  260 136 70   5.5   3.0
 36000 -51.0 -59.8  265 141 73   6.2   3.4 | -50.2 -58.4  260 146 75   5.5   3.0
 34000 -47.2 -53.0  260 144 74   6.7   3.7 | -46.3 -51.3  260 149 77   6.5   3.6
 32000 -42.7 -44.9  265 131 68   6.7   3.7 | -42.4 -44.3  260 137 71   6.5   3.6
 30000 -38.8 -37.8  265 121 62   6.3   3.5 | -38.5 -37.3  260 126 65   6.5   3.6
 29000 -36.8 -34.2  260 115 59   6.3   3.5 | -36.5 -33.7  260 122 63   6.5   3.6
 28000 -34.9 -30.8  260 109 56   6.3   3.5 | -34.6 -30.3  260 118 61   6.5   3.6
 27000 -33.1 -27.6  260 104 53   5.7   3.1 | -32.6 -26.7  260 114 59   6.1   3.3
 26000 -31.5 -24.7  260  97 50   5.4   2.9 | -30.9 -23.6  260 104 54   5.6   3.1
 25000 -29.9 -21.8  260  91 47   5.4   3.0 | -29.3 -20.7  260  95 49   5.6   3.1
 24000 -28.3 -18.9  260  85 44   6.0   3.3 | -27.6 -17.7  260  85 44   5.5   3.0
 23000 -26.2 -15.2  260  81 41   7.3   4.0 | -26.3 -15.3  260  78 40   3.9   2.1
 22000 -24.0 -11.2  260  76 39   7.3   4.0 | -25.2 -13.4  260  72 37   4.0   2.2
 21000 -21.9  -7.4  260  72 37   7.6   4.2 | -24.1 -11.4  260  66 34   6.1   3.3
 20000 -19.6  -3.3  260  69 35   7.8   4.3 | -21.6  -6.9  260  60 31   8.4   4.6
 19500 -18.4  -1.1  260  67 35   7.8   4.3 | -20.3  -4.5  260  57 29   8.4   4.6
 19000 -17.3   0.9  260  66 34   7.8   4.3 | -19.1  -2.4  260  54 28   8.4   4.6
 18500 -16.1   3.0  260  64 33   7.5   4.1 | -17.9  -0.2  260  51 26   8.2   4.5
 18000 -15.1   4.8  260  61 32   6.9   3.8 | -16.7   1.9  260  51 26   7.4   4.1
 17500 -14.1   6.6  260  58 30   6.9   3.8 | -15.6   3.9  260  52 27   7.5   4.1
 17000 -13.0   8.6  260  54 28   7.3   4.0 | -14.5   5.9  260  53 27   7.2   4.0
 16500 -12.0  10.4  255  48 25   7.3   4.0 | -13.4   7.9  265  53 28   7.2   4.0
 16000 -10.9  12.4  255  43 22   7.5   4.1 | -11.8  10.8  265  53 27   7.8   4.3
 15500  -9.8  14.4  250  39 20   7.6   4.2 | -10.6  12.9  265  53 27   7.8   4.3
 15000  -8.2  17.2  245  35 18   6.8   3.7 |  -9.5  14.9  265  52 27   8.1   4.5
 14500  -7.2  19.0  245  35 18   6.7   3.7 |  -8.3  17.1  265  51 26   8.2   4.5
 14000  -6.3  20.7  250  36 19   6.4   3.5 |  -7.1  19.2  260  50 26   7.7   4.2
 13500  -5.4  22.3  250  38 19   6.2   3.4 |  -6.0  21.2  260  49 25   7.3   4.0
 13000  -4.5  23.9  255  39 20   6.0   3.3 |  -5.0  23.0  260  47 24   7.1   3.9
 12500  -3.6  25.5  255  41 21   5.7   3.1 |  -4.0  24.8  260  46 24   6.8   3.7
 12000  -2.8  27.0  255  42 22   5.4   3.0 |  -3.1  26.4  255  45 23   6.8   3.7
 11500  -2.1  28.2  255  42 22   4.9   2.7 |  -2.1  28.2  255  45 23   6.6   3.6
 11000  -1.4  29.5  255  42 22   4.9   2.7 |  -1.2  29.8  260  44 23   6.2   3.4
 10500  -0.7  30.7  255  42 22   4.8   2.7 |  -0.4  31.3  255  44 23   4.9   2.7
 10250  -0.3  31.5  255  42 22   5.1   2.8 |  -0.0  32.0  255  44 23   6.8   3.8
 10000   0.1  32.2  255  42 21   5.9   3.2 |   0.5  32.9  255  44 23   7.7   4.2
  9750   0.5  32.9  250  42 22   6.3   3.5 |   1.0  33.8  250  43 22   6.0   3.3
  9500   1.0  33.8  250  42 22   6.0   3.3 |   1.5  34.7  250  42 21   5.9   3.2
  9250   1.4  34.5  250  42 22   6.8   3.8 |   1.9  35.4  250  40 21   6.6   3.6
  9000   2.0  35.6  250  42 22   6.5   3.6 |   2.4  36.3  245  39 20   7.5   4.1
  8750   2.4  36.3  250  42 21   5.6   3.1 |   3.0  37.4  245  37 19   7.5   4.1
  8500   2.8  37.0  245  41 21   5.7   3.1 |   3.5  38.3  245  35 18   7.1   3.9
  8250   3.3  37.9  245  40 21   6.2   3.4 |   4.0  39.2  240  32 17   8.6   4.7
  8000   3.8  38.8  240  38 20   6.9   3.8 |   4.8  40.6  240  30 15  10.2   5.6
  7750   4.3  39.7  240  36 19   6.6   3.6 |   5.5  41.9  240  28 14   9.4   5.2
  7500   4.7  40.5  240  34 17   6.1   3.4 |   6.2  43.2  240  26 13   8.9   4.9
  7250   5.2  41.4  240  32 16   7.5   4.1 |   6.9  44.4  240  24 12   9.6   5.3
  7000   5.9  42.6  235  29 15   8.7   4.8 |   7.6  45.7  240  23 12  10.3   5.6
  6750   6.5  43.7  235  26 14   7.8   4.3 |   8.4  47.1  240  21 11  10.2   5.6
  6500   7.1  44.8  235  24 12   8.0   4.4 |   9.1  48.4  240  20 10  10.2   5.6
  6250   7.7  45.9  235  21 11   9.3   5.1 |   9.9  49.8  240  19 10  10.4   5.7
  6000   8.4  47.1  235  19 10   9.2   5.0 |  10.7  51.3  240  17  9  10.7   5.9
  5750   9.1  48.4  230  16  8   7.4   4.0 |  11.5  52.7  240  16  8  12.2   6.7
  5500   9.5  49.1  230  12  6   4.0   2.2 |  12.5  54.5  240  14  7  11.9   6.5
  5250   9.7  49.5  230  12  6   0.5   0.3 |  13.2  55.8  240  14  7   8.8   4.8
  5000     M     M    M   M  M     M     M |     M     M    M   M  M     M     M

           11/17/2017 at 1400 MST          |       11/17/2017 at 1700 MST
                                           |
K index... +23.3  LI... -1.9               | K index... +27.9  LI... -3.2
CAPE... +185.1  CIN... -4.5                | CAPE... +213.4  CIN... -4.2
                                           |
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 -62.7 -80.9  270  85 44   2.7   1.5 | -61.7 -79.1  270  81 42   2.3   1.3
 45000 -58.4 -73.1  270 105 54   2.5   1.4 | -58.0 -72.4  270  94 48   2.9   1.6
 40000 -54.8 -66.6  265 127 66   2.5   1.3 | -53.5 -64.3  270 117 60   3.0   1.7
 38000 -52.6 -62.7  265 136 70   4.5   2.4 | -51.4 -60.5  265 126 65   4.0   2.2
 36000 -49.9 -57.8  260 146 75   4.5   2.4 | -48.9 -56.0  265 134 69   4.0   2.2
 34000 -47.1 -52.8  260 153 79   6.6   3.6 | -46.5 -51.7  265 140 72   4.8   2.6
 32000 -42.8 -45.0  260 143 73   6.4   3.5 | -43.3 -45.9  265 129 66   4.8   2.6
 30000 -39.2 -38.6  265 131 68   4.5   2.5 | -40.4 -40.7  265 119 61   5.1   2.8
 29000 -37.9 -36.2  265 121 62   4.5   2.5 | -38.8 -37.8  265 113 58   5.1   2.8
 28000 -36.5 -33.7  265 112 57   4.5   2.5 | -37.3 -35.1  265 107 55   5.1   2.8
 27000 -35.2 -31.4  265 102 52   5.0   2.7 | -35.8 -32.4  265 102 52   5.2   2.9
 26000 -33.3 -27.9  265  95 49   6.2   3.4 | -33.8 -28.8  265  98 50   6.8   3.7
 25000 -31.5 -24.7  265  89 46   6.2   3.4 | -31.8 -25.2  265  94 48   6.8   3.7
 24000 -29.6 -21.3  265  83 43   6.2   3.4 | -29.8 -21.6  265  91 47   6.9   3.8
 23000 -27.5 -17.5  265  79 41   7.1   3.9 | -28.0 -18.4  265  86 44   5.4   2.9
 22000 -25.4 -13.7  265  75 39   7.1   3.9 | -26.4 -15.5  265  80 41   5.4   3.0
 21000 -23.3  -9.9  265  72 37   7.0   3.9 | -24.8 -12.6  265  75 39   5.6   3.1
 20000 -21.2  -6.2  265  69 35   7.0   3.8 | -22.9  -9.2  265  69 36   6.4   3.5
 19500 -20.2  -4.4  265  67 35   7.0   3.9 | -22.0  -7.6  265  66 34   6.5   3.6
 19000 -19.1  -2.4  265  66 34   7.1   3.9 | -21.1  -6.0  265  63 32   6.6   3.6
 18500 -18.1  -0.6  265  65 33   7.2   3.9 | -20.1  -4.2  265  60 31   6.7   3.7
 18000 -17.0   1.4  265  64 33   8.0   4.4 | -19.0  -2.2  260  57 29   8.2   4.5
 17500 -15.8   3.6  260  63 32   8.0   4.4 | -17.9  -0.2  260  54 28   8.1   4.4
 17000 -14.7   5.5  260  62 32   7.5   4.1 | -16.6   2.1  260  52 27   9.2   5.1
 16500 -13.6   7.5  260  59 30   7.5   4.1 | -15.2   4.6  255  51 26   9.7   5.3
 16000 -12.5   9.5  260  56 29   7.4   4.1 | -13.8   7.2  255  50 26   9.6   5.3
 15500 -11.4  11.5  255  52 27   7.4   4.1 | -12.4   9.7  255  49 25   9.3   5.1
 15000  -9.8  14.4  255  46 24   8.0   4.4 | -10.4  13.3  255  49 25   9.0   5.0
 14500  -8.6  16.5  250  46 24   8.3   4.5 |  -9.1  15.6  255  49 25   8.8   4.8
 14000  -7.4  18.7  250  46 24   7.7   4.2 |  -7.8  18.0  255  48 25   8.3   4.6
 13500  -6.4  20.5  255  46 24   6.9   3.8 |  -6.7  19.9  255  48 25   7.3   4.0
 13000  -5.4  22.3  255  45 23   6.8   3.8 |  -5.7  21.7  260  47 24   7.2   4.0
 12500  -4.4  24.1  255  43 22   6.7   3.7 |  -4.7  23.5  260  47 24   6.6   3.6
 12000  -3.4  25.9  255  40 21   7.0   3.8 |  -3.7  25.3  260  47 24   6.5   3.6
 11500  -2.3  27.9  255  39 20   8.4   4.6 |  -2.9  26.8  260  46 24   5.7   3.1
 11000  -1.1  30.0  255  38 20   8.1   4.5 |  -2.0  28.4  260  45 23   5.7   3.1
 10500   0.0  32.0  250  37 19   7.1   3.9 |  -1.2  29.8  260  45 23   5.6   3.0
 10250   0.5  32.9  250  37 19   7.5   4.1 |  -0.8  30.6  260  45 23   6.9   3.8
 10000   1.1  34.0  245  36 19   8.4   4.6 |  -0.2  31.6  260  45 23   8.5   4.7
  9750   1.7  35.1  245  35 18   9.3   5.1 |   0.4  32.7  260  45 23   7.9   4.3
  9500   2.4  36.3  245  35 18   9.7   5.3 |   1.0  33.8  260  45 23   7.8   4.3
  9250   3.1  37.6  245  34 17   9.1   5.0 |   1.6  34.9  260  44 23   7.6   4.1
  9000   3.7  38.7  245  33 17   8.6   4.7 |   2.1  35.8  260  44 23   7.9   4.3
  8750   4.4  39.9  245  33 17   9.0   4.9 |   2.8  37.0  260  44 23   8.8   4.8
  8500   5.1  41.2  245  32 17   8.7   4.8 |   3.4  38.1  260  43 22   8.9   4.9
  8250   5.7  42.3  245  31 16  10.2   5.6 |   4.1  39.4  260  43 22   9.3   5.1
  8000   6.5  43.7  245  31 16  11.1   6.1 |   4.8  40.6  260  42 22  10.3   5.6
  7750   7.3  45.1  245  30 16   9.5   5.2 |   5.6  42.1  265  41 21   9.3   5.1
  7500   8.0  46.4  245  30 15   8.9   4.9 |   6.2  43.2  265  40 21   8.3   4.5
  7250   8.7  47.7  245  29 15   9.8   5.4 |   6.8  44.2  265  39 20   9.0   4.9
  7000   9.5  49.1  245  29 15  10.5   5.8 |   7.5  45.5  265  37 19   9.5   5.2
  6750  10.2  50.4  245  28 14   9.7   5.3 |   8.2  46.8  265  35 18   9.2   5.0
  6500  10.9  51.6  245  27 14   9.0   4.9 |   8.9  48.0  265  33 17   8.8   4.8
  6250  11.6  52.9  245  26 13  10.8   5.9 |   9.5  49.1  265  31 16   9.1   5.0
  6000  12.5  54.5  245  25 13  11.9   6.5 |  10.2  50.4  265  29 15   9.1   5.0
  5750  13.3  55.9  245  23 12   9.8   5.4 |  10.9  51.6  265  26 13   9.5   5.2
  5500  14.0  57.2  245  20 10  10.0   5.5 |  11.6  52.9  265  21 11   7.5   4.1
  5250  14.9  58.8  245  19 10  12.9   7.1 |  11.9  53.4  265  20 10   1.8   1.0
  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.