Soaring Guidance
Issued by NWS Denver/Boulder, CO

Home | Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24
000
UXUS97 KBOU 201337
SRGBOU

Soaring Forecast
National Weather Service Denver/Boulder, Colorado
0737 MDT Wednesday, May 20, 2015

This forecast is for Wednesday, May 20, 2015:

If the trigger temperature of 53.6 F/12.0 C is reached...then
   Thermal Soaring Index....................... Poor
   Maximum rate of lift........................ 0 ft/min (0.0 m/s)
   Maximum height of thermals.................. 8722 ft MSL (3437 ft AGL)

Forecast maximum temperature................... 50.0 F/10.5 C
Time of trigger temperature.................... None
Time of overdevelopment........................ None
Middle/high clouds during soaring window....... Broken/overcast opaque middle
Surface winds during soaring window............ 20 mph or less
Height of the -3 thermal index................. 8412 ft MSL (3126 ft AGL)
Thermal soaring outlook for Thursday 05/21..... Fair

Wave Soaring Index............................. Poor
Wave Soaring Index trend (to 1800 MDT)......... Becoming fair by 1000
Height of stable layer (12-18K ft MSL)......... 14865 ft MSL (9580 ft AGL)
Weak PVA/NVA (through 1800 MDT)................ Weak NVA
Potential height of wave....................... 15356 ft MSL (10071 ft AGL)
Wave soaring outlook for Thursday 05/21........ Poor

Remarks...

Sunrise/Sunset.................... 05:40:56 / 20:10:54 MDT
Total possible sunshine........... 14 hr 29 min 58 sec (869 min 58 sec)
Altitude of sun at 12:56:07 MDT... 70.24 degrees

Upper air data from rawinsonde observation taken on 05/20/2015 at 0600 MDT

Freezing level.................. 6511 ft MSL (1226 ft AGL)
Convective condensation level... 12431 ft MSL (7146 ft AGL)
Lifted condensation level....... 9957 ft MSL (4672 ft AGL)
Lifted index.................... +4.9
K index......................... +13.1

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  -60.4 -76.7   240   46   24  10.3   5.6   98.0 208.4    50.5      M    M
 45000  -54.6 -66.3   240   60   31   2.2   1.2   83.3 181.9    44.9      M    M
 40000  -52.8 -63.0   245   67   35  -1.2  -0.7   62.1 143.8    34.3      M    M
 38000  -52.2 -62.0   250   78   40  -4.3  -2.4   54.3 129.7    29.9      M    M
 36000  -53.0 -63.4   255   91   47   2.8   1.5   44.5 112.0    23.9      M    M
 34000  -50.9 -59.6   255   86   44   8.8   4.8   39.1 102.4    20.7      M    M
 32000  -46.3 -51.3   260   81   42   5.1   2.8   37.3  99.1    19.9      M    M
 30000  -42.3 -44.1   260   77   40   8.6   4.7   34.9  94.7    18.6      M    M
 29000  -39.8 -39.6   260   77   40   8.5   4.6   34.4  93.9    18.5      M    M
 28000  -37.2 -35.0   260   64   33   5.6   3.0   32.9  91.2    17.6      M    M
 27000  -36.7 -34.1   260   53   27   0.2   0.1   29.8  85.7    15.5      M    M
 26000  -35.5 -31.9   260   43   22   7.4   4.1   27.7  81.8    14.0      M    M
 25000  -33.1 -27.6   260   40   20   8.6   4.7   27.0  80.7    13.6      M    M
 24000  -30.5 -22.9   255   35   18   9.0   5.0   26.6  80.0    13.5      M    M
 23000  -28.5 -19.3   255   30   16   8.9   4.9   25.5  78.0    12.7      M    M
 22000  -25.9 -14.6   255   26   13   8.4   4.6   25.1  77.2    12.5      M    M
 21000  -23.7 -10.7   255   22   11   9.1   5.0   24.3  75.7    11.9      M    M
 20000  -20.9  -5.6   255   17    9   9.3   5.1   24.2  75.5    12.0      M    M
 19500  -19.5  -3.1   255   17    9   9.3   5.1   24.1  75.4    11.9      M    M
 19000  -18.2  -0.8   255   18    9   9.3   5.1   24.0  75.2    11.9      M    M
 18500  -16.8   1.8   255   18    9   9.6   5.3   24.0  75.1    12.0      M    M
 18000  -15.5   4.1   265   18    9   7.8   4.3   23.7  74.7    11.9      M    M
 17500  -14.3   6.3   270   19   10   8.0   4.4   23.4  74.2    11.6      M    M
 17000  -13.1   8.4   275   20   10   8.1   4.4   23.1  73.6    11.4      M    M
 16500  -11.9  10.6   280   21   11   8.4   4.6   22.9  73.1    11.2      M    M
 16000  -10.9  12.4   285   22   11   3.9   2.1   22.4  72.2    10.8      M    M
 15500  -10.2  13.6   290   24   12   5.4   3.0   21.5  70.7    10.1      M    M
 15000   -9.6  14.7   290   26   14  -2.0  -1.1   20.7  69.2     9.4      M    M
 14500   -9.9  14.2   295   29   15   5.8   3.2   18.8  65.8     7.6      M    M
 14000   -8.4  16.9   295   31   16   7.4   4.1   18.1  64.6     7.0      M    M
 13500   -7.3  18.9   290   29   15   7.5   4.1   17.7  63.9     6.7      M    M
 13000   -6.2  20.8   290   26   14   7.5   4.1   17.3  63.2     6.3      M    M
 12500   -5.1  22.8   285   24   12   7.5   4.1   17.0  62.5     6.0      M    M
 12000   -4.0  24.8   280   22   11   7.4   4.1   16.6  61.9     5.7      M    M
 11500   -2.9  26.8   280   21   11   6.6   3.6   16.3  61.3     5.3      M    M
 11000   -2.1  28.2   280   20   10   5.7   3.1   15.6  60.0     4.7      M    M
 10500   -1.2  29.8   280   20   10   5.7   3.1   14.9  58.9     4.1      M    M
 10250   -0.8  30.6   280   19   10   5.5   3.0   14.6  58.3     3.8      M    M
 10000   -0.4  31.3   280   19   10   5.6   3.1   14.3  57.7     3.5      M    M
  9750   -0.1  31.8   285   20   10   2.5   1.4   13.9  57.0     3.1      M    M
  9500   -0.1  31.8   285   20   10   0.2   0.1   13.2  55.7     2.4      M    M
  9250   -0.0  32.0   290   21   11   0.3   0.2   12.4  54.4     1.7      M    M
  9000   -0.0  32.0   290   20   11   2.2   1.2   11.7  53.1     1.0      M    M
  8750   -0.3  31.5   285   16    8 -18.5 -10.2   10.7  51.3     0.0      M    M
  8500   -2.3  27.9   280   11    6 -19.4 -10.7    7.9  46.2    -2.7    323  1.6
  8250   -2.6  27.3   270    7    4   4.5   2.5    6.8  44.3    -3.8    324  1.6
  8000   -2.3  27.9   235    4    2   5.3   2.9    6.5  43.7    -4.1    306  1.6
  7750   -1.9  28.6   255    4    2   5.1   2.8    6.1  43.0    -4.5    287  1.5
  7500   -1.5  29.3   265    5    3   5.2   2.8    5.8  42.4    -4.8    268  1.4
  7250   -1.1  30.0   280    6    3   5.2   2.8    5.4  41.8    -5.2    250  1.3
  7000   -0.8  30.6   285    7    4   5.2   2.8    5.1  41.2    -5.6    231  1.2
  6750   -0.4  31.3   300    5    3   5.1   2.8    4.7  40.5    -5.9    213  1.1
  6500   -0.0  32.0   320    4    2   5.4   2.9    4.4  39.9    -6.3    194  1.0
  6250    0.4  32.7   355    4    2   6.1   3.4    4.1  39.4    -6.6    174  0.9
  6000    0.9  33.6   025    5    3   6.6   3.6    3.8  38.9    -6.9    153  0.8
  5750    1.3  34.3   025    5    3   6.1   3.4    3.6  38.5    -7.2    132  0.7
  5500    1.8  35.2   020    5    3   7.5   4.1    3.3  38.0    -7.5    111  0.6

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

           05/20/2015 at 0900 MDT          |       05/20/2015 at 1200 MDT
                                           |
K index... +19.2  LI... +274.3             | K index... +17.2  LI... +273.3
CAPE... 0.0  CIN... -0.2                   | CAPE... 0.0  CIN... -18.0
                                           |
Height Temperature  Wnd WndSpd  Lapse Rate | Temperature  Wnd WndSpd  Lapse Rate
ft MSL deg C deg F  Dir kt m/s  C/km F/kft | deg C deg F  Dir kt m/s  C/km F/kft
--------------------------------------------------------------------------------
 50000 -57.7 -71.9  245  38 20   2.2   1.2 | -58.0 -72.4  245  37 19   1.8   1.0
 45000 -54.7 -66.5  250  50 26  -2.0  -1.1 | -55.6 -68.1  250  51 26  -2.5  -1.4
 40000 -57.4 -71.3  255  76 39  -1.7  -0.9 | -58.8 -73.8  255  78 40  -1.8  -1.0
 38000 -55.7 -68.3  260  79 41   5.1   2.8 | -56.5 -69.7  255  80 41   6.0   3.3
 36000 -52.7 -62.9  260  78 40   5.1   2.8 | -52.9 -63.2  255  79 40   6.0   3.3
 34000 -49.2 -56.6  265  78 40   7.3   4.0 | -49.0 -56.2  260  76 39   7.5   4.1
 32000 -44.8 -48.6  265  77 40   7.4   4.0 | -44.6 -48.3  260  72 37   7.5   4.1
 30000 -40.0 -40.0  265  72 37   6.5   3.6 | -39.5 -39.1  265  68 35   7.8   4.3
 29000 -38.1 -36.6  270  67 35   6.5   3.6 | -37.2 -35.0  265  66 34   7.8   4.3
 28000 -36.1 -33.0  270  63 32   6.6   3.6 | -34.8 -30.6  265  64 33   7.8   4.3
 27000 -34.2 -29.6  270  57 29   5.5   3.0 | -32.6 -26.7  265  61 31   6.3   3.4
 26000 -32.5 -26.5  265  48 24   5.7   3.1 | -30.7 -23.3  265  55 28   6.4   3.5
 25000 -30.9 -23.6  265  38 20   5.7   3.1 | -28.8 -19.8  265  49 25   6.4   3.5
 24000 -29.1 -20.4  260  30 15   7.3   4.0 | -26.9 -16.4  265  43 22   6.0   3.3
 23000 -26.8 -16.2  260  27 14   7.7   4.2 | -25.1 -13.2  265  36 19   6.0   3.3
 22000 -24.5 -12.1  260  23 12   7.7   4.2 | -23.4 -10.1  255  30 16   6.0   3.3
 21000 -22.2  -8.0  255  21 11   7.2   4.0 | -21.6  -6.9  250  26 13   6.2   3.4
 20000 -20.1  -4.2  255  21 11   7.3   4.0 | -19.7  -3.5  255  22 11   6.3   3.4
 19500 -19.0  -2.2  255  21 11   7.3   4.0 | -18.8  -1.8  255  21 11   6.3   3.5
 19000 -17.9  -0.2  255  20 10   7.3   4.0 | -17.9  -0.2  260  19 10   6.2   3.4
 18500 -16.8   1.8  255  20 10   7.5   4.1 | -16.9   1.6  260  19 10   8.1   4.4
 18000 -15.7   3.7  255  20 10   7.5   4.1 | -15.7   3.7  255  20 10   8.0   4.4
 17500 -14.6   5.7  255  19 10   7.5   4.1 | -14.5   5.9  255  21 11   7.9   4.3
 17000 -13.5   7.7  260  19 10   7.5   4.1 | -13.3   8.1  260  20 10   7.7   4.2
 16500 -12.4   9.7  260  18  9   7.5   4.1 | -12.2  10.0  265  18  9   7.7   4.2
 16000 -11.4  11.5  265  17  9   7.0   3.9 | -11.0  12.2  270  19 10   8.6   4.7
 15500  -9.8  14.4  270  17  9   7.2   3.9 |  -9.1  15.6  275  21 11   8.0   4.4
 15000  -8.7  16.3  275  18  9   7.5   4.1 |  -8.1  17.4  280  22 11   6.5   3.6
 14500  -7.6  18.3  280  18  9   7.5   4.1 |  -7.2  19.0  285  23 12   6.6   3.6
 14000  -6.6  20.1  285  19 10   7.1   3.9 |  -6.0  21.2  285  24 12   9.1   5.0
 13500  -5.5  22.1  285  20 10   7.2   3.9 |  -4.7  23.5  285  23 12   9.1   5.0
 13000  -4.5  23.9  290  21 11   7.5   4.1 |  -3.6  25.5  290  23 12   6.6   3.6
 12500  -3.4  25.9  290  22 11   7.4   4.1 |  -2.6  27.3  290  22 11   6.8   3.8
 12000  -2.3  27.9  290  23 12   7.8   4.3 |  -1.6  29.1  295  20 10   7.0   3.8
 11500  -1.1  30.0  290  23 12   7.9   4.4 |  -0.6  30.9  295  18  9   7.0   3.9
 11000  -0.0  32.0  290  23 12   6.7   3.7 |   0.4  32.7  295  16  8   6.3   3.4
 10500   0.9  33.6  290  22 11   7.2   3.9 |   1.3  34.3  295  14  7   7.0   3.9
 10250   1.4  34.5  290  21 11   4.2   2.3 |   1.7  35.1  295  12  6   3.3   1.8
 10000   1.5  34.7  290  21 11   1.8   1.0 |   1.8  35.2  295  12  6   1.1   0.6
  9750   1.7  35.1  290  19 10   3.0   1.6 |   2.0  35.6  290  11  5   3.3   1.8
  9500   1.9  35.4  290  18  9   3.9   2.1 |   2.2  36.0  290   9  5   3.5   1.9
  9250   2.1  35.8  290  16  8   0.2   0.1 |   2.4  36.3  285   8  4  -0.2  -0.1
  9000   1.9  35.4  290  14  7  -4.1  -2.2 |   2.1  35.8  285   7  3  -4.2  -2.3
  8750   1.6  34.9  290  12  6  -5.2  -2.8 |   1.8  35.2  280   5  3  -5.0  -2.7
  8500   1.1  34.0  295  10  5  -6.5  -3.6 |   1.4  34.5  285   4  2  -6.2  -3.4
  8250   0.6  33.1  295   7  4  -5.9  -3.2 |   0.9  33.6  285   2  1  -6.5  -3.6
  8000   0.2  32.4  295   5  3  -6.6  -3.6 |   0.4  32.7  000   0  0  -7.1  -3.9
  7750  -0.3  31.5  295   3  2  -2.0  -1.1 |  -0.0  32.0  105   2  1  -2.2  -1.2
  7500  -0.1  31.8  300   2  1   4.0   2.2 |   0.1  32.2  095   3  1   6.9   3.8
  7250   0.2  32.4  325   1  1   4.6   2.5 |   0.8  33.4  085   4  2  10.4   5.7
  7000   0.5  32.9  360   1  1   5.1   2.8 |   1.5  34.7  075   5  2   9.9   5.4
  6750   0.9  33.6  025   1  1   4.1   2.3 |   2.2  36.0  070   6  3  10.3   5.6
  6500   1.2  34.2  030   2  1   5.2   2.9 |   3.0  37.4  070   7  3  10.7   5.9
  6250   1.6  34.9  055   3  1   6.8   3.7 |   3.8  38.8  065   7  3  10.8   6.4
  6000   2.1  35.8  065   4  2   6.6   3.6 |   4.6  40.3  065   7  3  10.4   5.7
  5750   2.7  36.9  070   5  3  11.0   6.0 |   5.5  41.9  065   7  3  15.6   8.5
  5500   3.7  38.7  070   5  3  16.8   9.2 |   7.0  44.6  065   7  4  25.0  13.7

           05/20/2015 at 1500 MDT          |       05/20/2015 at 1800 MDT
                                           |
K index... +21.3  LI... +273.5             | K index... +23.4  LI... +274.8
CAPE... 0.0  CIN... -1.4                   | 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 -58.4 -73.1  250  36 18   0.9   0.5 | -59.2 -74.6  245  38 20   0.9   0.5
 45000 -57.2 -71.0  255  54 28  -1.4  -0.8 | -58.0 -72.4  250  49 25  -1.0  -0.5
 40000 -59.0 -74.2  255  76 39  -0.9  -0.5 | -59.2 -74.6  260  74 38  -0.6  -0.3
 38000 -56.7 -70.1  255  78 40   5.6   3.1 | -56.9 -70.4  260  76 39   5.5   3.0
 36000 -53.3 -63.9  255  78 40   5.6   3.1 | -53.6 -64.5  255  75 38   5.5   3.0
 34000 -49.4 -56.9  255  75 39   7.8   4.3 | -49.8 -57.6  255  69 36   8.0   4.4
 32000 -44.7 -48.5  260  69 36   7.8   4.3 | -45.0 -49.0  260  57 30   8.0   4.4
 30000 -39.3 -38.7  260  63 32   8.4   4.6 | -39.5 -39.1  265  48 25   8.3   4.6
 29000 -36.8 -34.2  260  60 31   8.4   4.6 | -37.0 -34.6  265  46 24   8.4   4.6
 28000 -34.3 -29.7  265  57 29   8.4   4.6 | -34.5 -30.1  270  44 23   8.3   4.6
 27000 -31.9 -25.4  265  54 28   7.2   4.0 | -32.2 -26.0  270  42 22   7.2   4.0
 26000 -29.8 -21.6  265  50 26   7.3   4.0 | -30.0 -22.0  270  41 21   7.2   4.0
 25000 -27.6 -17.7  270  47 24   7.3   4.0 | -27.9 -18.2  270  39 20   7.2   4.0
 24000 -25.6 -14.1  270  43 22   5.1   2.8 | -25.7 -14.3  270  37 19   6.8   3.7
 23000 -24.0 -11.2  270  39 20   5.2   2.9 | -23.7 -10.7  265  36 18   6.9   3.8
 22000 -22.5  -8.5  265  34 18   5.2   2.9 | -21.7  -7.1  265  34 18   6.9   3.8
 21000 -20.8  -5.4  270  31 16   6.4   3.5 | -19.7  -3.5  265  32 16   7.0   3.8
 20000 -18.9  -2.0  270  29 15   6.4   3.5 | -17.6   0.3  260  28 14   7.0   3.8
 19500 -18.0  -0.4  270  28 15   6.4   3.5 | -16.6   2.1  255  26 13   7.0   3.8
 19000 -17.1   1.2  275  28 14   6.2   3.4 | -15.6   3.9  255  24 12   7.0   3.8
 18500 -16.0   3.2  270  27 14   8.3   4.6 | -14.5   5.9  250  23 12   7.5   4.1
 18000 -14.9   5.2  270  25 13   8.2   4.5 | -13.4   7.9  255  21 11   7.4   4.1
 17500 -13.7   7.3  265  23 12   7.7   4.2 | -12.4   9.7  255  20 10   6.6   3.6
 17000 -12.6   9.3  265  22 11   7.2   4.0 | -11.5  11.3  255  19 10   5.9   3.2
 16500 -11.6  11.1  265  20 11   7.2   4.0 | -10.7  12.7  255  19 10   5.9   3.2
 16000 -10.5  13.1  260  19 10   7.3   4.0 |  -9.8  14.4  255  18  9   6.6   3.6
 15500  -8.9  16.0  260  18  9   7.3   4.0 |  -8.3  17.1  250  17  9   6.4   3.5
 15000  -7.9  17.8  255  17  9   7.3   4.0 |  -7.4  18.7  250  16  8   6.2   3.4
 14500  -6.8  19.8  250  16  8   7.4   4.0 |  -6.5  20.3  245  15  8   6.2   3.4
 14000  -5.7  21.7  245  15  8   7.8   4.3 |  -5.6  21.9  240  14  7   6.2   3.4
 13500  -4.5  23.9  240  15  8   7.9   4.3 |  -4.7  23.5  230  13  7   6.2   3.4
 13000  -3.5  25.7  235  14  7   7.0   3.8 |  -3.9  25.0  225  13  7   5.6   3.1
 12500  -2.4  27.7  230  13  7   7.2   3.9 |  -3.1  26.4  215  13  7   5.8   3.2
 12000  -1.4  29.5  220  12  6   6.0   3.3 |  -2.3  27.9  205  14  7   4.9   2.7
 11500  -0.5  31.1  215  10  5   6.2   3.4 |  -1.6  29.1  200  14  7   5.0   2.7
 11000   0.2  32.4  205   9  5   4.0   2.2 |  -0.9  30.4  195  14  7   4.1   2.3
 10500   0.8  33.4  200   8  4   4.6   2.5 |  -0.3  31.5  195  13  7   4.7   2.6
 10250   1.1  34.0  195   8  4   2.1   1.2 |  -0.0  32.0  195  13  7   2.2   1.2
 10000   1.1  34.0  195   7  4  -1.2  -0.7 |   0.0  32.0  190  13  6   1.0   0.5
  9750   1.0  33.8  195   7  3  -1.3  -0.7 |   0.2  32.4  190  11  5   2.5   1.4
  9500   0.9  33.6  190   6  3  -1.2  -0.6 |   0.3  32.5  185   9  4   2.2   1.2
  9250   0.7  33.3  185   5  2  -3.3  -1.8 |   0.5  32.9  175   7  4   1.0   0.5
  9000   0.4  32.7  170   4  2  -3.7  -2.0 |   0.5  32.9  155   5  3   1.4   0.8
  8750   0.2  32.4  140   3  2  -1.5  -0.8 |   0.7  33.3  125   5  2   4.3   2.4
  8500   0.1  32.2  110   4  2   1.5   0.8 |   1.1  34.0  095   5  3   5.5   3.0
  8250   0.4  32.7  095   5  3   6.9   3.8 |   1.5  34.7  080   6  3   6.2   3.4
  8000   1.0  33.8  085   5  3   8.8   4.8 |   2.0  35.6  070   7  4   6.7   3.7
  7750   1.7  35.1  075   6  3   9.0   5.0 |   2.5  36.5  060   7  4   7.1   3.9
  7500   2.4  36.3  065   6  3  10.4   5.7 |   3.0  37.4  055   8  4   8.8   4.8
  7250   3.1  37.6  065   6  3  10.7   5.9 |   3.7  38.7  055   8  4   9.7   5.3
  7000   3.9  39.0  060   6  3  10.7   5.9 |   4.4  39.9  055   8  4   9.4   5.2
  6750   4.7  40.5  060   6  3  10.1   5.5 |   5.1  41.2  055   8  4   9.5   5.2
  6500   5.4  41.7  060   6  3   9.9   5.4 |   5.9  42.6  050   7  4   9.8   5.4
  6250   6.2  43.2  055   6  3  10.5   5.8 |   6.6  43.9  050   7  4   9.8   5.4
  6000   7.0  44.6  055   6  3  10.0   5.5 |   7.3  45.1  050   7  4  10.5   5.8
  5750   7.8  46.0  055   6  3  14.7   8.1 |   8.2  46.8  050   7  4  12.4   6.8
  5500   9.2  48.6  055   6  3  23.2  12.7 |   9.1  48.4  045   7  3  13.2   7.2
________________________________________________________________________________

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 near the old Stapleton
Airport site in Denver, Colorado at

                   North Latitude:  39 deg 46 min 5.016 sec
                   West Longitude: 104 deg 52 min 9.984 sec
                   Elevation: 5285 feet (1611 meters)

and may not be representative of other areas along the Front Range of the
Colorado Rocky Mountains.  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.