Soaring Guidance
Issued by NWS Denver/Boulder, CO

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary Off
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 25 26 27 28

000
UXUS97 KBOU 200046
SRGBOU

Soaring Forecast
National Weather Service Denver/Boulder, Colorado
1746 MST Monday, January 19, 2015

This forecast is for Tuesday, January 20, 2015:

If the trigger temperature of 43.3 F/6.3 C is reached...then
   Thermal Soaring Index....................... Poor
   Maximum rate of lift........................ 18 ft/min (0.1 m/s)
   Maximum height of thermals.................. 8467 ft MSL (3180 ft AGL)

Forecast maximum temperature................... 41.0 F/5.5 C
Time of trigger temperature.................... None
Time of overdevelopment........................ 1700 MST
Middle/high clouds during soaring window....... Broken/overcast thin middle
Surface winds during soaring window............ 20 mph or less
Height of the -3 thermal index................. 6278 ft MSL (991 ft AGL)
Thermal soaring outlook for Wednesday 01/21.... Poor

Wave Soaring Index............................. Poor
Wave Soaring Index trend (to 1700 MST)......... No change
Height of stable layer (12-18K ft MSL)......... None
Weak PVA/NVA (through 1700 MST)................ Weak NVA
Potential height of wave....................... 33828 ft MSL (28541 ft AGL)
Wave soaring outlook for Wednesday 01/21....... Poor

Remarks...

Sunrise/Sunset.................... 07:16:22 / 17:03:42 MST
Total possible sunshine........... 9 hr 47 min 20 sec (587 min 20 sec)
Altitude of sun at 12:10:25 MST... 30.23 degrees

Upper air data from numerical model forecast valid on 01/20/2015 at 0500 MST

Freezing level.................. 5472 ft MSL (185 ft AGL)
Convective condensation level... 8732 ft MSL (3445 ft AGL)
Lifted condensation level....... 8556 ft MSL (3269 ft AGL)
Lifted index.................... +3.9
K index......................... +15.0

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  -57.5 -71.5   285   42   22   1.1   0.6      M     M       M      M    M
 45000  -55.7 -68.3   290   57   29   1.1   0.6      M     M       M      M    M
 40000  -55.5 -67.9   295   66   34  -0.0  -0.0      M     M       M      M    M
 38000  -55.7 -68.3   295   69   35  -1.7  -1.0      M     M       M      M    M
 36000  -56.6 -69.9   295   71   36  -1.6  -0.9      M     M       M      M    M
 34000  -57.6 -71.7   300   73   38  -1.8  -1.0      M     M       M      M    M
 32000  -55.3 -67.5   300   75   39   5.1   2.8      M     M       M      M    M
 30000  -51.8 -61.2   305   77   40   6.4   3.5      M     M       M      M    M
 29000  -49.5 -57.1   305   75   39   7.7   4.2   22.7  72.9    13.4      M    M
 28000  -47.2 -53.0   305   74   38   7.8   4.3   21.9  71.4    12.9      M    M
 27000  -44.9 -48.8   305   72   37   7.7   4.2   21.2  70.2    12.6      M    M
 26000  -42.5 -44.5   305   71   36   8.2   4.5   20.6  69.0    12.2      M    M
 25000  -40.0 -40.0   305   70   36   8.2   4.5   19.9  67.9    11.9      M    M
 24000  -37.5 -35.5   310   69   35   8.2   4.5   19.4  67.0    11.6      M    M
 23000  -34.9 -30.8   310   67   35   9.0   4.9   19.0  66.2    11.4      M    M
 22000  -32.2 -26.0   310   66   34   9.0   4.9   18.7  65.7    11.3      M    M
 21000  -29.5 -21.1   310   65   33   9.0   4.9   18.5  65.3    11.3      M    M
 20000  -26.9 -16.4   310   62   32   8.7   4.8   18.1  64.6    11.1      M    M
 19500  -25.6 -14.1   310   61   31   8.7   4.8   17.9  64.2    11.0      M    M
 19000  -24.3 -11.7   310   60   31   8.7   4.8   17.7  63.9    10.9      M    M
 18500  -23.0  -9.4   310   58   30   9.2   5.0   17.6  63.7    10.8      M    M
 18000  -22.1  -7.8   305   56   29   3.7   2.0   17.0  62.6    10.4      M    M
 17500  -21.4  -6.5   305   52   27   4.2   2.3   16.1  60.9     9.6      M    M
 17000  -20.8  -5.4   305   48   25   4.2   2.3   15.1  59.2     8.8      M    M
 16500  -20.2  -4.4   300   44   23   4.2   2.3   14.2  57.5     8.0      M    M
 16000  -19.6  -3.3   295   41   21   4.5   2.5   13.2  55.8     7.2      M    M
 15500  -18.9  -2.0   295   37   19   5.3   2.9   12.4  54.3     6.5      M    M
 15000  -17.7   0.1   290   33   17   6.8   3.7   11.3  52.4     5.5      M    M
 14500  -16.6   2.1   290   31   16   7.5   4.1   11.0  51.7     5.2      M    M
 14000  -15.5   4.1   290   29   15   7.7   4.2   10.6  51.1     4.9      M    M
 13500  -14.4   6.1   290   28   14   7.7   4.2   10.3  50.5     4.5      M    M
 13000  -13.2   8.2   295   27   14   7.7   4.2   10.0  49.9     4.2      M    M
 12500  -12.1  10.2   295   25   13   7.6   4.2    9.6  49.3     3.9      M    M
 12000  -11.0  12.2   300   23   12   7.5   4.1    9.3  48.7     3.6      M    M
 11500   -9.9  14.2   305   21   11   7.3   4.0    8.9  48.0     3.2      M    M
 11000   -8.8  16.2   310   19   10   7.2   3.9    8.5  47.3     2.9      M    M
 10500   -7.8  18.0   310   17    9   7.2   4.0    8.0  46.5     2.5      M    M
 10250   -7.3  18.9   315   16    8   6.3   3.4    7.8  46.1     2.2      M    M
 10000   -7.0  19.4   315   15    8   3.6   2.0    7.5  45.4     1.9      M    M
  9750   -6.7  19.9   315   14    7   6.0   3.3    7.0  44.6     1.4      M    M
  9500   -6.1  21.0   315   13    7   9.0   4.9    6.9  44.4     1.3      M    M
  9250   -5.5  22.1   315   12    6   7.1   3.9    6.7  44.1     1.2      M    M
  9000   -5.1  22.8   315   11    6   4.4   2.4    6.4  43.6     0.9      M    M
  8750   -4.8  23.4   310    9    5   4.3   2.4    6.0  42.8     0.4      M    M
  8500   -4.4  24.1   310    7    4   5.3   2.9    5.6  42.1     0.0      M    M
  8250   -4.1  24.6   305    5    3   5.0   2.7    5.3  41.5    -0.3    201  1.0
  8000   -3.7  25.3   310    4    2   4.8   2.6    4.9  40.8    -0.7    183  0.9
  7750   -3.4  25.9   330    2    1   5.5   3.0    4.5  40.1    -1.1    165  0.8
  7500   -2.9  26.8   360    2    1   6.3   3.5    4.2  39.6    -1.4    145  0.7
  7250   -2.5  27.5   020    3    1   6.6   3.6    4.0  39.2    -1.7    123  0.6
  7000   -2.0  28.4   030    3    2   6.9   3.8    3.7  38.7    -1.9    101  0.5
  6750   -1.5  29.3   035    4    2   6.6   3.6    3.5  38.4    -2.1     79  0.4
  6500   -1.1  30.0   040    5    2   4.1   2.2    3.2  37.8    -2.5     59  0.3
  6250   -0.9  30.4   030    4    2   2.5   1.4    2.7  36.8    -3.0     46  0.2
  6000   -0.7  30.7   025    4    2   2.7   1.5    2.2  35.9    -3.5     32  0.2
  5750   -0.5  31.1   015    4    2   3.7   2.0    1.7  35.0    -4.1     19  0.1
  5500   -0.1  31.8   010    3    2   6.4   3.5    1.3  34.4    -4.4      0  0.0

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

           01/20/2015 at 0800 MST          |       01/20/2015 at 1100 MST
                                           |
K index... -1.9  LI... +5.6                | K index... -10.1  LI... +5.6
CAPE... 0.0  CIN... -1.1                   | CAPE... +1.1  CIN... -0.9
                                           |
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 -57.2 -71.0  290  38 19   1.3   0.7 | -57.2 -71.0  285  37 19   1.3   0.7
 45000 -55.2 -67.4  295  54 28   1.3   0.7 | -55.2 -67.4  290  50 26   1.2   0.7
 40000 -55.8 -68.4  295  64 33  -0.6  -0.3 | -56.7 -70.1  295  62 32  -1.3  -0.7
 38000 -56.3 -69.3  295  68 35  -1.9  -1.0 | -57.5 -71.5  295  67 34  -1.1  -0.6
 36000 -57.4 -71.3  295  72 37  -1.8  -1.0 | -58.1 -72.6  295  73 38  -1.1  -0.6
 34000 -58.4 -73.1  295  76 39  -2.2  -1.2 | -58.8 -73.8  295  79 41  -1.7  -1.0
 32000 -55.4 -67.7  295  77 39   6.7   3.6 | -55.3 -67.5  295  79 41   7.2   3.9
 30000 -50.9 -59.6  300  76 39   7.2   4.0 | -50.5 -58.9  295  78 40   7.2   4.0
 29000 -48.6 -55.5  300  75 38   7.7   4.2 | -48.4 -55.1  295  75 39   7.2   3.9
 28000 -46.3 -51.3  300  73 38   7.7   4.2 | -46.2 -51.2  295  72 37   7.2   3.9
 27000 -44.0 -47.2  300  71 37   7.7   4.2 | -44.0 -47.2  295  69 36   7.2   3.9
 26000 -41.7 -43.1  300  69 36   7.5   4.1 | -41.9 -43.4  295  66 34   7.3   4.0
 25000 -39.5 -39.1  300  66 34   7.5   4.1 | -39.7 -39.5  295  62 32   7.3   4.0
 24000 -37.2 -35.0  305  63 32   7.5   4.1 | -37.5 -35.5  295  59 30   7.3   4.0
 23000 -34.9 -30.8  300  60 31   7.9   4.3 | -35.2 -31.4  300  57 29   8.1   4.5
 22000 -32.5 -26.5  300  58 30   7.9   4.3 | -32.7 -26.9  300  55 28   8.1   4.5
 21000 -30.2 -22.4  300  55 28   7.9   4.3 | -30.3 -22.5  300  54 28   8.2   4.5
 20000 -27.5 -17.5  300  54 28   9.2   5.0 | -27.7 -17.9  300  51 26   8.7   4.8
 19500 -26.1 -15.0  305  53 27   9.2   5.0 | -26.4 -15.5  300  49 25   8.7   4.8
 19000 -24.7 -12.5  305  52 27   9.2   5.0 | -25.1 -13.2  300  48 25   8.7   4.8
 18500 -23.4 -10.1  305  51 26   9.4   5.2 | -23.8 -10.8  300  46 24   8.7   4.8
 18000 -22.1  -7.8  305  50 26   6.9   3.8 | -22.6  -8.7  300  44 23   7.2   3.9
 17500 -21.1  -6.0  305  49 25   7.2   3.9 | -21.5  -6.7  300  43 22   7.3   4.0
 17000 -20.0  -4.0  305  48 24   6.0   3.3 | -20.5  -4.9  300  41 21   6.7   3.7
 16500 -19.2  -2.6  300  44 23   5.5   3.0 | -19.5  -3.1  300  40 21   6.5   3.6
 16000 -18.4  -1.1  300  41 21   5.1   2.8 | -18.5  -1.3  300  39 20   6.0   3.3
 15500 -17.8  -0.0  300  39 20   4.0   2.2 | -17.7   0.1  305  38 19   4.9   2.7
 15000 -16.9   1.6  300  37 19   4.3   2.3 | -16.6   2.1  305  35 18   5.0   2.8
 14500 -16.2   2.8  300  36 18   4.4   2.4 | -15.9   3.4  305  33 17   5.1   2.8
 14000 -15.6   3.9  300  35 18   5.0   2.7 | -15.1   4.8  305  31 16   5.6   3.1
 13500 -14.8   5.4  295  34 17   5.7   3.1 | -14.2   6.4  305  30 15   6.1   3.3
 13000 -14.0   6.8  295  32 17   6.0   3.3 | -13.3   8.1  305  29 15   6.2   3.4
 12500 -13.0   8.6  300  31 16   6.5   3.6 | -12.4   9.7  305  29 15   6.2   3.4
 12000 -12.1  10.2  300  29 15   6.5   3.6 | -11.5  11.3  305  29 15   5.7   3.1
 11500 -11.1  12.0  305  27 14   6.5   3.6 | -10.8  12.6  300  28 14   5.1   2.8
 11000 -10.2  13.6  310  26 13   6.6   3.6 | -10.1  13.8  300  27 14   5.6   3.1
 10500  -9.2  15.4  310  22 12   6.9   3.8 |  -9.2  15.4  305  24 13   6.3   3.4
 10250  -8.7  16.3  315  21 11   6.3   3.5 |  -8.8  16.2  305  23 12   5.3   2.9
 10000  -8.3  17.1  315  20 10   3.8   2.1 |  -8.5  16.7  305  22 11   3.2   1.7
  9750  -8.1  17.4  315  19 10   5.0   2.8 |  -8.2  17.2  305  21 11   5.3   2.9
  9500  -7.6  18.3  320  17  9   7.7   4.2 |  -7.7  18.1  310  18  9   7.6   4.2
  9250  -7.1  19.2  320  15  8   5.7   3.1 |  -7.2  19.0  310  16  8   5.9   3.3
  9000  -6.8  19.8  325  14  7   2.8   1.5 |  -6.8  19.8  315  14  7   4.2   2.3
  8750  -6.6  20.1  325  13  7   3.7   2.0 |  -6.5  20.3  320  13  6   4.2   2.3
  8500  -6.3  20.7  330  11  6   4.8   2.6 |  -6.2  20.8  320  10  5   4.3   2.4
  8250  -5.9  21.4  330  10  5   6.0   3.3 |  -5.9  21.4  325   8  4   5.7   3.1
  8000  -5.4  22.3  330   9  5   6.8   3.7 |  -5.4  22.3  325   7  4   6.5   3.6
  7750  -4.9  23.2  325   8  4   9.2   5.0 |  -5.0  23.0  330   6  3   7.3   4.0
  7500  -4.1  24.6  325   7  3  10.6   5.8 |  -4.4  24.1  325   4  2   8.1   4.5
  7250  -3.5  25.7  330   6  3   7.6   4.2 |  -3.8  25.2  320   4  2   7.4   4.0
  7000  -3.0  26.6  335   5  3   7.3   4.0 |  -3.3  26.1  315   3  1   7.4   4.1
  6750  -2.4  27.7  340   5  2   7.2   3.9 |  -2.8  27.0  310   2  1   7.5   4.1
  6500  -2.0  28.4  350   4  2   5.9   3.2 |  -2.2  28.0  295   1  1   8.5   4.6
  6250  -1.6  29.1  355   3  2   5.6   3.1 |  -1.6  29.1  280   1  0   9.1   5.0
  6000  -1.2  29.8  005   3  2   4.8   2.6 |  -0.9  30.4  255   1  0   8.9   4.9
  5750  -0.8  30.6  025   3  2   5.4   3.0 |  -0.2  31.6  240   1  0  12.7   7.0
  5500  -0.3  31.5  020   2  1   9.3   5.1 |   1.0  33.8  235   1  0  18.8  10.3

           01/20/2015 at 1400 MST          |       01/20/2015 at 1700 MST
                                           |
K index... -9.8  LI... +5.4                | K index... -5.7  LI... +4.6
CAPE... 0.0  CIN... -0.1                   | CAPE... +0.9  CIN... -4.9
                                           |
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 -57.4 -71.3  285  38 20   1.2   0.7 | -57.5 -71.5  285  36 18   1.3   0.7
 45000 -55.6 -68.1  290  55 28   1.3   0.7 | -55.6 -68.1  290  54 28   1.3   0.7
 40000 -57.3 -71.1  285  64 33  -1.6  -0.9 | -57.1 -70.8  285  71 37  -1.4  -0.8
 38000 -58.2 -72.8  285  68 35  -0.8  -0.4 | -57.9 -72.2  285  77 39  -0.5  -0.3
 36000 -58.7 -73.7  285  72 37  -0.9  -0.5 | -58.3 -72.9  285  78 40  -0.6  -0.3
 34000 -59.2 -74.6  285  76 39  -1.5  -0.8 | -58.6 -73.5  285  80 41  -0.9  -0.5
 32000 -55.7 -68.3  285  77 40   7.2   3.9 | -55.5 -67.9  285  77 40   6.4   3.5
 30000 -51.4 -60.5  285  77 40   7.2   4.0 | -51.7 -61.1  285  74 38   6.4   3.5
 29000 -48.4 -55.1  290  75 39   8.2   4.5 | -49.4 -56.9  285  73 37   7.8   4.3
 28000 -45.9 -50.6  290  74 38   8.2   4.5 | -46.5 -51.7  285  70 36   7.8   4.3
 27000 -43.4 -46.1  290  72 37   8.3   4.5 | -44.2 -47.6  285  68 35   7.9   4.3
 26000 -41.2 -42.2  290  69 36   6.9   3.8 | -42.0 -43.6  290  65 34   7.0   3.8
 25000 -39.2 -38.6  290  66 34   6.9   3.8 | -39.9 -39.8  290  62 32   7.0   3.8
 24000 -37.1 -34.8  295  62 32   6.8   3.8 | -37.8 -36.0  290  59 30   7.0   3.8
 23000 -34.9 -30.8  295  60 31   8.2   4.5 | -35.5 -31.9  290  56 29   8.2   4.5
 22000 -32.4 -26.3  295  58 30   8.2   4.5 | -33.0 -27.4  295  55 28   8.2   4.5
 21000 -30.0 -22.0  300  56 29   8.2   4.5 | -30.6 -23.1  295  53 28   8.2   4.5
 20000 -27.5 -17.5  300  54 28   8.0   4.4 | -28.1 -18.6  295  50 26   8.1   4.4
 19500 -26.3 -15.3  300  53 27   8.0   4.4 | -26.9 -16.4  295  49 25   8.1   4.4
 19000 -25.1 -13.2  300  52 27   8.0   4.4 | -25.7 -14.3  300  47 24   8.1   4.4
 18500 -23.9 -11.0  300  50 26   8.0   4.4 | -24.5 -12.1  300  45 23   8.0   4.4
 18000 -22.7  -8.9  300  49 25   8.4   4.6 | -23.2  -9.8  300  44 23   9.1   5.0
 17500 -21.5  -6.7  300  46 24   8.4   4.6 | -21.9  -7.4  300  43 22   9.0   4.9
 17000 -20.2  -4.4  295  44 23   7.4   4.1 | -20.6  -5.1  300  42 22   7.8   4.3
 16500 -19.2  -2.6  295  42 22   7.0   3.8 | -19.5  -3.1  300  42 22   7.3   4.0
 16000 -18.1  -0.6  295  40 21   6.6   3.6 | -18.4  -1.1  305  42 22   6.8   3.8
 15500 -17.2   1.0  300  38 20   5.7   3.1 | -17.5   0.5  300  40 21   5.7   3.1
 15000 -16.4   2.5  300  37 19   5.7   3.1 | -16.6   2.1  300  37 19   5.7   3.1
 14500 -15.2   4.6  300  34 18   5.0   2.7 | -15.6   3.9  300  34 17   4.3   2.4
 14000 -14.5   5.9  300  33 17   5.0   2.8 | -15.0   5.0  300  32 16   4.5   2.5
 13500 -13.8   7.2  300  32 16   5.1   2.8 | -14.3   6.3  295  30 16   4.8   2.7
 13000 -13.0   8.6  300  30 16   4.7   2.6 | -13.6   7.5  295  29 15   4.5   2.5
 12500 -12.4   9.7  300  29 15   3.8   2.1 | -13.0   8.6  290  26 13   4.0   2.2
 12000 -11.9  10.6  295  28 14   4.3   2.4 | -12.5   9.5  285  23 12   4.8   2.6
 11500 -11.2  11.8  295  25 13   5.2   2.8 | -11.7  10.9  285  19 10   5.9   3.3
 11000 -10.5  13.1  295  21 11   6.0   3.3 | -10.9  12.4  285  14  7   6.6   3.6
 10500  -9.5  14.9  295  17  9   7.1   3.9 |  -9.8  14.4  285  12  6   7.4   4.0
 10250  -9.0  15.8  295  16  8   6.4   3.5 |  -9.3  15.3  285  11  6   6.5   3.5
 10000  -8.6  16.5  295  14  7   4.4   2.4 |  -8.9  16.0  280  11  5   4.9   2.7
  9750  -8.3  17.1  295  13  7   6.1   3.3 |  -8.5  16.7  285  10  5   7.4   4.1
  9500  -7.7  18.1  295  11  6   8.3   4.6 |  -7.8  18.0  285   9  4   9.9   5.4
  9250  -7.2  19.0  295  10  5   7.0   3.9 |  -7.1  19.2  285   7  4   8.0   4.4
  9000  -6.7  19.9  300   8  4   5.6   3.1 |  -6.6  20.1  285   6  3   5.6   3.1
  8750  -6.3  20.7  300   7  4   6.1   3.4 |  -6.2  20.8  285   5  2   6.2   3.4
  8500  -5.8  21.6  305   5  3   6.7   3.7 |  -5.7  21.7  290   3  2   7.1   3.9
  8250  -5.3  22.5  315   4  2   7.1   3.9 |  -5.2  22.6  300   2  1   7.6   4.2
  8000  -4.7  23.5  330   2  1   7.6   4.2 |  -4.6  23.7  335   1  0   8.3   4.6
  7750  -4.2  24.4  005   1  1   8.6   4.7 |  -4.0  24.8  040   1  0   9.1   5.0
  7500  -3.5  25.7  030   1  1   9.7   5.3 |  -3.3  26.1  060   1  1   9.9   5.4
  7250  -2.8  27.0  040   1  1   9.6   5.3 |  -2.6  27.3  065   1  1   9.5   5.2
  7000  -2.1  28.2  040   1  1   9.5   5.2 |  -1.8  28.8  065   1  1   9.5   5.2
  6750  -1.4  29.5  045   1  1  10.4   5.7 |  -1.1  30.0  065   1  1   9.4   5.1
  6500  -0.6  30.9  050   1  1  10.8   5.9 |  -0.4  31.3  065   2  1   9.8   5.4
  6250   0.2  32.4  050   1  1  10.4   5.7 |   0.3  32.5  065   2  1  10.2   5.6
  6000   1.0  33.8  050   1  1   9.7   5.3 |   1.1  34.0  065   2  1  10.2   5.6
  5750   1.7  35.1  050   1  1  11.9   6.5 |   1.8  35.2  065   2  1   8.8   4.8
  5500   2.8  37.0  055   2  1  18.4  10.1 |   2.3  36.1  070   2  1   6.1   3.4
________________________________________________________________________________

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.