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 25 26
210
UXUS97 KBOU 151250
SRGBOU

Soaring Forecast
National Weather Service Denver/Boulder, Colorado
0650 MDT Sunday, April 15, 2018

This forecast is for Sunday, April 15, 2018:

If the trigger temperature of 50.8 F/10.5 C is reached...then
   Thermal Soaring Index....................... Excellent
   Maximum rate of lift........................ 995 ft/min (5.1 m/s)
   Maximum height of thermals.................. 17701 ft MSL (12416 ft AGL)

Forecast maximum temperature................... 63.0 F/17.7 C
Time of trigger temperature.................... 1030 MDT
Time of overdevelopment........................ 1800 MDT
Middle/high clouds during soaring window....... Overcast thin high
Surface winds during soaring window............ 20 mph or less
Height of the -3 thermal index................. 14138 ft MSL (8852 ft AGL)
Thermal soaring outlook for Monday 04/16....... Excellent

Wave Soaring Index............................. Good
Wave Soaring Index trend (to 1800 MDT)......... Little change
Height of stable layer (12-18K ft MSL)......... 18089 ft MSL (12804 ft AGL)
Weak PVA/NVA (through 1800 MDT)................ Neither
Potential height of wave....................... 38032 ft MSL (32747 ft AGL)
Wave soaring outlook for Monday 04/16.......... Good

Remarks... Upper level ridge building over colorado today with moderate
           northwest flow aloft in the morning becoming westerly.

Sunrise/Sunset.................... 06:21:28 / 19:37:27 MDT
Total possible sunshine........... 13 hr 15 min 59 sec (795 min 59 sec)
Altitude of sun at 12:59:27 MDT... 60.17 degrees

Upper air data from rawinsonde observation taken on 04/15/2018 at 0600 MDT

Freezing level.................. 8622 ft MSL (3337 ft AGL)
Convective condensation level... 13727 ft MSL (8442 ft AGL)
Lifted condensation level....... 15321 ft MSL (10035 ft AGL)
Lifted index.................... +3.0
K index......................... +9.2

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  -64.4 -83.9   290   68   35  -0.6  -0.3   92.0 197.5    42.7      M    M
 45000  -55.4 -67.7   300   64   33   2.8   1.5   81.2 178.2    39.3      M    M
 40000  -51.2 -60.2   300   97   50   2.8   1.5   64.8 148.7    31.3      M    M
 38000  -49.4 -56.9   305  104   53  -2.0  -1.1   58.8 137.9    28.0      M    M
 36000  -50.3 -58.5   310  102   52  -1.5  -0.8   48.7 119.6    21.8      M    M
 34000  -49.4 -56.9   310  100   52   6.8   3.7   41.7 107.1    17.4      M    M
 32000  -45.3 -49.5   310  101   52   6.9   3.8   39.3 102.7    16.1      M    M
 30000  -40.6 -41.1   310   94   48   7.1   3.9   36.9  98.5    14.8      M    M
 29000  -38.5 -37.3   310   89   46   7.1   3.9   35.7  96.3    14.0      M    M
 28000  -36.3 -33.3   315   84   43   7.1   3.9   34.6  94.3    13.4      M    M
 27000  -34.2 -29.6   315   79   41   7.1   3.9   33.7  92.7    12.8      M    M
 26000  -32.5 -26.5   320   74   38   3.3   1.8   32.2  90.0    11.8      M    M
 25000  -31.5 -24.7   320   70   36   3.4   1.9   29.8  85.7    10.1      M    M
 24000  -30.5 -22.9   315   64   33   3.8   2.1   27.5  81.4     8.2      M    M
 23000  -28.6 -19.5   315   60   31   6.6   3.6   26.1  79.0     7.2      M    M
 22000  -26.6 -15.9   320   56   29   6.9   3.8   25.0  76.9     6.4      M    M
 21000  -24.5 -12.1   320   52   27   7.0   3.8   24.0  75.1     5.6      M    M
 20000  -22.7  -8.9   325   48   25   5.5   3.0   22.7  72.8     4.6      M    M
 19500  -21.9  -7.4   320   46   24   5.8   3.2   21.9  71.4     3.9      M    M
 19000  -20.9  -5.6   320   43   22   7.5   4.1   21.4  70.5     3.5      M    M
 18500  -19.9  -3.8   315   41   21   1.2   0.7   20.9  69.6     3.1      M    M
 18000  -20.4  -4.7   315   40   21  -4.4  -2.4   18.6  65.4     1.1      M    M
 17500  -20.1  -4.2   315   40   21   8.3   4.6   17.3  63.1    -0.1   1085  5.5
 17000  -19.1  -2.4   320   39   20   7.1   3.9   16.8  62.2    -0.5   1039  5.3
 16500  -18.0  -0.4   320   39   20   7.1   3.9   16.4  61.5    -0.9    993  5.0
 16000  -17.0   1.4   320   38   20   7.1   3.9   16.0  60.7    -1.3    947  4.8
 15500  -15.4   4.3   320   36   19   7.1   3.9   15.3  59.5    -1.9    877  4.5
 15000  -14.4   6.1   320   35   18   7.1   3.9   14.8  58.7    -2.4    831  4.2
 14500  -13.3   8.1   320   33   17   7.1   3.9   14.4  57.9    -2.8    785  4.0
 14000  -12.3   9.9   320   31   16   7.1   3.9   14.0  57.1    -3.2    739  3.8
 13500  -11.2  11.8   325   29   15   7.1   3.9   13.5  56.3    -3.7    693  3.5
 13000  -10.2  13.6   330   27   14   7.1   3.9   13.1  55.5    -4.1    647  3.3
 12500   -9.1  15.6   325   25   13   7.8   4.3   12.6  54.8    -4.6    600  3.0
 12000   -7.9  17.8   325   24   12   8.0   4.4   12.4  54.3    -4.8    549  2.8
 11500   -6.7  19.9   325   23   12   8.1   4.4   12.1  53.7    -5.2    499  2.5
 11000   -5.5  22.1   320   22   11   8.1   4.4   11.8  53.2    -5.5    448  2.3
 10500   -4.3  24.3   320   22   11   8.1   4.4   11.5  52.8    -5.7    397  2.0
 10250   -3.7  25.3   320   21   11   8.0   4.4   11.4  52.6    -5.9    372  1.9
 10000   -3.2  26.2   315   20   10   7.9   4.3   11.3  52.3    -6.0    347  1.8
  9750   -2.6  27.3   315   19   10   7.9   4.3   11.1  52.1    -6.2    322  1.6
  9500   -2.0  28.4   315   18    9   7.9   4.3   11.0  51.8    -6.4    297  1.5
  9250   -1.4  29.5   320   18    9   7.9   4.3   10.9  51.5    -6.5    272  1.4
  9000   -0.8  30.6   320   17    9   7.9   4.3   10.7  51.3    -6.7    248  1.3
  8750   -0.3  31.5   320   15    8   7.9   4.4   10.6  51.0    -6.9    223  1.1
  8500    0.3  32.5   325   13    7   7.8   4.3   10.4  50.7    -7.0    198  1.0
  8250    0.9  33.6   325   12    6   8.4   4.6   10.3  50.5    -7.2    173  0.9
  8000    1.4  34.5   330   10    5   1.7   0.9   10.0  50.0    -7.5    152  0.8
  7750    1.2  34.2   330    9    4  -3.5  -1.9    9.1  48.3    -8.4    150  0.8
  7500    1.0  33.8   330    8    4  -3.2  -1.7    8.1  46.6    -9.4    148  0.8
  7250    0.8  33.4   335    6    3   0.8   0.5    7.2  44.9   -10.3    146  0.7
  7000    1.2  34.2   335    5    3   6.7   3.7    6.8  44.2   -10.7    127  0.6
  6750    1.7  35.1   340    3    2   6.7   3.7    6.6  43.8   -10.9    105  0.5
  6500    2.2  36.0   005    2    1   6.0   3.3    6.3  43.4   -11.2     83  0.4
  6250    2.7  36.9   085    1    1   8.9   4.9    6.1  42.9   -11.5     61  0.3
  6000    3.2  37.8   120    3    1  -2.0  -1.1    5.8  42.5   -11.7     38  0.2
  5750    2.3  36.1   120    4    2 -15.8  -8.7    4.2  39.6   -13.4     58  0.3
  5500    1.3  34.3   115    4    2  -5.8  -3.2    2.6  36.6   -15.1     79  0.4

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

           04/15/2018 at 0900 MDT          |       04/15/2018 at 1200 MDT
                                           |
CAPE...     0.0    LI...       +3.8        | CAPE...     0.0    LI...       +3.9
CINH...    -0.2    K Index... +13.3        | CINH...    -0.1    K Index... +10.9
                                           |
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 -61.0 -77.8  290  28 14   2.4   1.3 | -61.4 -78.5  280  27 14   2.3   1.2
 45000 -57.1 -70.8  290  35 18   3.9   2.1 | -57.6 -71.7  285  36 18   4.0   2.2
 40000 -51.4 -60.5  290  44 23   3.8   2.1 | -51.8 -61.2  285  42 22   3.9   2.1
 38000 -50.1 -58.2  295  46 24   1.3   0.7 | -50.5 -58.9  290  43 22   1.2   0.7
 36000 -49.3 -56.7  300  47 24   1.3   0.7 | -49.8 -57.6  290  43 22   1.2   0.7
 34000 -48.2 -54.8  300  48 25   5.7   3.1 | -48.6 -55.5  295  43 22   5.6   3.1
 32000 -44.5 -48.1  305  48 25   5.4   3.0 | -44.9 -48.8  295  42 22   5.5   3.0
 30000 -41.1 -42.0  305  47 24   6.5   3.6 | -41.3 -42.3  295  41 21   7.1   3.9
 29000 -39.2 -38.6  305  44 23   6.5   3.6 | -39.2 -38.6  295  39 20   7.1   3.9
 28000 -37.2 -35.0  305  41 21   6.5   3.6 | -37.1 -34.8  295  37 19   7.1   3.9
 27000 -35.3 -31.5  305  39 20   6.2   3.4 | -34.9 -30.8  295  35 18   6.6   3.6
 26000 -33.5 -28.3  305  36 19   5.9   3.2 | -33.1 -27.6  300  34 17   6.3   3.4
 25000 -31.7 -25.1  305  33 17   5.9   3.2 | -31.2 -24.2  300  32 16   6.3   3.4
 24000 -30.0 -22.0  305  31 16   6.0   3.3 | -29.3 -20.7  300  30 15   6.3   3.5
 23000 -28.1 -18.6  310  28 15   6.4   3.5 | -27.4 -17.3  300  28 14   6.4   3.5
 22000 -26.2 -15.2  310  26 13   6.4   3.5 | -25.5 -13.9  300  26 13   6.4   3.5
 21000 -24.3 -11.7  310  24 12   6.0   3.3 | -23.6 -10.5  300  24 12   6.5   3.5
 20000 -22.6  -8.7  310  22 11   5.7   3.2 | -21.7  -7.1  305  22 12   6.5   3.6
 19500 -21.7  -7.1  315  21 11   5.8   3.2 | -20.7  -5.3  305  21 11   6.5   3.6
 19000 -20.9  -5.6  315  20 11   5.8   3.2 | -19.7  -3.5  305  21 11   6.5   3.5
 18500 -20.0  -4.0  315  20 10   5.7   3.1 | -18.8  -1.8  305  20 10   6.2   3.4
 18000 -18.8  -1.8  315  19 10   5.6   3.1 | -17.4   0.7  305  19 10   6.0   3.3
 17500 -17.9  -0.2  315  18  9   5.6   3.1 | -16.5   2.3  305  18  9   6.0   3.3
 17000 -17.1   1.2  315  17  9   5.6   3.1 | -15.7   3.7  305  17  9   5.9   3.3
 16500 -16.3   2.7  315  17  9   5.7   3.1 | -14.8   5.4  310  17  9   5.9   3.3
 16000 -15.4   4.3  315  16  8   6.3   3.4 | -13.9   7.0  310  16  8   5.9   3.3
 15500 -14.5   5.9  315  16  8   6.2   3.4 | -13.0   8.6  310  16  8   5.9   3.2
 15000 -13.6   7.5  315  16  8   6.6   3.6 | -12.1  10.2  310  15  8   6.3   3.5
 14500 -12.6   9.3  315  15  8   6.6   3.6 | -11.2  11.8  310  15  8   6.3   3.5
 14000 -11.6  11.1  315  15  8   6.7   3.7 | -10.3  13.5  305  14  7   6.4   3.5
 13500 -10.6  12.9  315  14  7   6.7   3.7 |  -9.3  15.3  305  14  7   6.4   3.5
 13000  -9.6  14.7  320  14  7   6.7   3.7 |  -8.4  16.9  305  13  7   6.8   3.7
 12500  -8.7  16.3  320  13  7   6.7   3.7 |  -7.4  18.7  305  12  6   6.9   3.8
 12000  -7.7  18.1  320  12  6   6.8   3.7 |  -6.4  20.5  300  11  6   6.9   3.8
 11500  -6.7  19.9  320  12  6   6.9   3.8 |  -5.4  22.3  300  10  5   6.9   3.8
 11000  -5.7  21.7  325  11  6   7.0   3.8 |  -4.3  24.3  300   8  4   6.9   3.8
 10500  -4.6  23.7  325  10  5   7.0   3.8 |  -3.3  26.1  305   7  4   6.7   3.7
 10250  -4.1  24.6  325  10  5   7.3   4.0 |  -2.8  27.0  305   6  3   7.6   4.2
 10000  -3.6  25.5  330   9  5   7.3   4.0 |  -2.2  28.0  305   6  3   7.3   4.0
  9750  -3.1  26.4  330   9  5   6.9   3.8 |  -1.8  28.8  310   5  2   6.1   3.3
  9500  -2.6  27.3  330   8  4   6.9   3.8 |  -1.3  29.7  315   4  2   6.6   3.6
  9250  -2.0  28.4  335   8  4   6.8   3.7 |  -0.8  30.6  320   3  2   5.8   3.2
  9000  -1.6  29.1  335   8  4   6.7   3.7 |  -0.4  31.3  330   2  1   6.0   3.3
  8750  -1.0  30.2  340   7  4   7.3   4.0 |   0.1  32.2  350   2  1   7.7   4.2
  8500  -0.5  31.1  340   7  4   7.6   4.2 |   0.7  33.3  015   1  1   8.2   4.5
  8250   0.1  32.2  345   6  3   6.9   3.8 |   1.3  34.3  040   1  1   9.0   4.9
  8000   0.6  33.1  345   6  3   6.7   3.7 |   2.0  35.6  055   2  1   9.8   5.4
  7750   1.0  33.8  350   5  3   5.6   3.1 |   2.7  36.9  065   2  1   9.4   5.1
  7500   1.4  34.5  350   5  2   5.2   2.9 |   3.4  38.1  065   2  1   9.6   5.3
  7250   1.9  35.4  355   4  2   6.5   3.6 |   4.1  39.4  065   2  1  10.0   5.5
  7000   2.3  36.1  360   3  2   6.6   3.6 |   4.9  40.8  070   2  1  10.2   5.6
  6750   2.8  37.0  005   3  1   6.5   3.6 |   5.7  42.3  070   2  1   9.8   5.4
  6500   3.3  37.9  010   2  1   6.6   3.6 |   6.4  43.5  070   2  1  10.1   5.5
  6250   3.8  38.8  020   1  1   7.2   3.9 |   7.2  45.0  070   2  1  11.1   6.1
  6000   4.4  39.9  040   1  0   6.0   3.3 |   8.0  46.4  075   2  1   9.6   5.3
  5750   4.9  40.8  090   1  0  10.1   5.5 |   8.8  47.8  075   2  1  14.5   8.0
  5500   6.0  42.8  120   1  0  19.5  10.7 |  10.3  50.5  075   2  1  27.7  15.2

           04/15/2018 at 1500 MDT          |       04/15/2018 at 1800 MDT
                                           |
CAPE...     0.0    LI...       +2.5        | CAPE...     0.0    LI...       +1.1
CINH...    -0.0    K Index... +14.4        | CINH...     0.0    K Index... +18.4
                                           |
Height Temperature  Wnd WndSpd  Lapse Rate | Temperature  Wnd WndSpd  Lapse Rate
ft MSL deg C deg F  Dir kt m/s  C/km F/kft | deg C deg F  Dir kt m/s  C/km F/kft
--------------------------------------------------------------------------------
 50000 -61.4 -78.5  270  28 14   2.5   1.4 | -61.8 -79.2  265  28 14   3.1   1.7
 45000 -57.5 -71.5  280  35 18   3.6   2.0 | -57.1 -70.8  275  33 17   3.3   1.8
 40000 -52.2 -62.0  280  40 21   3.6   2.0 | -52.1 -61.8  275  39 20   3.3   1.8
 38000 -50.9 -59.6  285  41 21   1.2   0.7 | -51.0 -59.8  280  40 21   1.1   0.6
 36000 -50.2 -58.4  285  40 21   1.2   0.7 | -50.3 -58.5  280  41 21   1.1   0.6
 34000 -48.4 -55.1  285  40 21   6.0   3.3 | -48.5 -55.3  285  41 21   6.3   3.5
 32000 -44.8 -48.6  290  39 20   6.0   3.3 | -44.7 -48.5  285  41 21   6.3   3.5
 30000 -41.0 -41.8  290  38 20   7.3   4.0 | -40.7 -41.3  285  40 20   7.4   4.1
 29000 -38.8 -37.8  290  36 19   7.3   4.0 | -38.5 -37.3  285  38 20   7.4   4.1
 28000 -36.6 -33.9  290  35 18   7.3   4.0 | -36.3 -33.3  285  36 19   7.4   4.1
 27000 -34.4 -29.9  290  33 17   6.7   3.7 | -34.1 -29.4  285  34 18   6.7   3.7
 26000 -32.5 -26.5  290  32 16   6.6   3.6 | -32.1 -25.8  285  32 17   6.6   3.6
 25000 -30.5 -22.9  290  30 16   6.6   3.6 | -30.2 -22.4  285  30 15   6.6   3.6
 24000 -28.5 -19.3  290  29 15   6.4   3.5 | -28.2 -18.8  285  28 14   6.3   3.5
 23000 -26.7 -16.1  290  27 14   6.0   3.3 | -26.4 -15.5  285  27 14   6.0   3.3
 22000 -24.9 -12.8  290  25 13   6.0   3.3 | -24.6 -12.3  285  25 13   6.0   3.3
 21000 -23.1  -9.6  290  24 12   6.5   3.6 | -22.8  -9.0  285  24 12   6.3   3.5
 20000 -21.1  -6.0  290  22 11   6.7   3.7 | -20.9  -5.6  285  22 11   6.4   3.5
 19500 -20.1  -4.2  290  22 11   6.7   3.7 | -19.5  -3.1  285  21 11   6.4   3.5
 19000 -18.6  -1.5  290  21 11   6.7   3.7 | -18.6  -1.5  285  20 10   6.4   3.5
 18500 -17.7   0.1  290  20 10   6.3   3.4 | -17.6   0.3  285  19 10   6.6   3.6
 18000 -16.7   1.9  290  19 10   6.3   3.5 | -16.6   2.1  280  19 10   6.6   3.6
 17500 -15.8   3.6  290  19 10   6.2   3.4 | -15.6   3.9  280  18  9   7.0   3.8
 17000 -14.9   5.2  290  18  9   6.2   3.4 | -14.6   5.7  280  17  9   7.2   3.9
 16500 -14.0   6.8  290  18  9   6.2   3.4 | -13.5   7.7  280  17  9   7.2   4.0
 16000 -13.0   8.6  290  17  9   6.5   3.6 | -12.4   9.7  280  16  8   7.4   4.1
 15500 -12.1  10.2  290  16  8   6.4   3.5 | -11.4  11.5  280  15  8   7.4   4.1
 15000 -11.1  12.0  285  15  8   7.0   3.8 | -10.2  13.6  275  14  7   7.7   4.2
 14500 -10.1  13.8  285  14  7   6.9   3.8 |  -9.1  15.6  275  13  7   7.6   4.2
 14000  -9.1  15.6  285  13  7   7.4   4.1 |  -8.0  17.6  275  12  6   8.2   4.5
 13500  -8.0  17.6  280  12  6   7.5   4.1 |  -6.7  19.9  275  11  5   8.2   4.5
 13000  -6.9  19.6  280  11  6   7.7   4.2 |  -5.5  22.1  270   9  5   8.1   4.4
 12500  -5.7  21.7  275  10  5   7.8   4.3 |  -4.3  24.3  265   8  4   8.1   4.4
 12000  -4.6  23.7  275   8  4   7.8   4.3 |  -3.2  26.2  260   6  3   7.9   4.3
 11500  -3.4  25.9  270   7  3   7.8   4.3 |  -2.0  28.4  245   5  3   7.8   4.3
 11000  -2.3  27.9  265   5  3   7.6   4.1 |  -0.8  30.6  225   4  2   8.0   4.4
 10500  -1.1  30.0  260   3  2   7.3   4.0 |   0.4  32.7  205   3  2   8.1   4.5
 10250  -0.6  30.9  250   2  1   8.0   4.4 |   1.0  33.8  190   3  2   8.1   4.5
 10000   0.0  32.0  230   2  1   8.3   4.5 |   1.6  34.9  180   3  2   8.7   4.8
  9750   0.6  33.1  215   1  1   7.8   4.3 |   2.3  36.1  170   3  2   9.1   5.0
  9500   1.2  34.2  180   1  0   8.0   4.4 |   2.9  37.2  160   3  2   9.0   4.9
  9250   1.8  35.2  150   1  1   7.8   4.3 |   3.6  38.5  155   3  2   9.0   5.0
  9000   2.4  36.3  135   1  1   8.7   4.8 |   4.3  39.7  145   3  2   9.3   5.1
  8750   3.1  37.6  125   1  1   9.6   5.3 |   5.0  41.0  140   3  2   9.5   5.2
  8500   3.8  38.8  120   2  1   9.7   5.3 |   5.7  42.3  140   3  2   9.6   5.2
  8250   4.5  40.1  115   2  1   9.7   5.3 |   6.4  43.5  135   3  2   9.4   5.2
  8000   5.2  41.4  110   2  1   9.7   5.3 |   7.1  44.8  135   3  2   9.4   5.1
  7750   6.0  42.8  110   2  1   9.9   5.4 |   7.8  46.0  130   4  2   9.8   5.4
  7500   6.7  44.1  105   2  1   9.9   5.4 |   8.6  47.5  130   4  2   9.9   5.5
  7250   7.4  45.3  105   2  1   9.6   5.3 |   9.3  48.7  130   4  2   9.7   5.3
  7000   8.2  46.8  105   2  1   9.5   5.2 |  10.0  50.0  125   4  2   9.5   5.2
  6750   8.9  48.0  100   2  1  10.3   5.7 |  10.8  51.4  125   4  2   9.7   5.3
  6500   9.7  49.5  100   2  1  10.9   6.0 |  11.5  52.7  125   4  2  10.0   5.5
  6250  10.5  50.9  100   2  1  10.9   6.0 |  12.2  54.0  125   3  2  10.2   5.6
  6000  11.3  52.3  100   2  1  10.1   5.6 |  13.0  55.4  120   3  2   9.9   5.5
  5750  12.1  53.8  095   2  1  13.0   7.1 |  13.8  56.8  120   3  2  10.7   5.9
  5500  13.4  56.1  095   2  1  23.7  13.0 |  14.7  58.5  120   3  2  14.7   8.1
________________________________________________________________________________

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.

CINH (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.