Soaring Guidance
Issued by NWS Denver/Boulder, CO

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14
000
UXUS97 KBOU 100033
SRGBOU

Soaring Forecast
National Weather Service Denver/Boulder, Colorado
533 PM MST Tuesday February 9, 2010

This forecast is for Wednesday February 10, 2010:

If the trigger temperature of 42.1 F/5.6 C is reached...then
   Thermal Soaring Index....................... Fair
   Maximum rate of lift........................ 252 ft/min (1.3 m/s)
   Maximum height of thermals.................. 8949 ft MSL (3626 ft AGL)

Forecast maximum temperature................... 41.0 F/5.5 C
Time of trigger temperature.................... 1415 MST
Time of overdevelopment........................ 1700 MST
Middle/high clouds during soaring window....... None
Surface winds during soaring window............ 20 mph or less
Height of the -3 thermal index................. 7173 ft MSL (1849 ft AGL)
Thermal soaring outlook for Thursday 02/11..... Good

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)................ Neither
Potential height of wave....................... 34184 ft MSL (28861 ft AGL)
Wave soaring outlook for Thursday 02/11........ Poor

Remarks... None

Sunrise/Sunset.................... 06:57:49 / 17:28:41 MST
Total possible sunshine........... 10 hr 30 min 52 sec (630 min 52 sec)
Altitude of sun at 12:13:35 MST... 36.08 degrees

Upper air data from numerical model forecast valid on 02/10/2010 at 0500 MST

Freezing level.................. Entire airmass below 32 F / 0 C
Convective condensation level... 16184 ft MSL (10861 ft AGL)
Lifted condensation level....... 13679 ft MSL (8356 ft AGL)
Lifted index.................... +6.5
K index......................... +0.9

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  -54.7 -66.5   269   39   20   1.1   0.6  110.4 230.8    60.0      M    M
 45000  -53.1 -63.6   263   48   25   1.1   0.6   89.5 193.1    51.3      M    M
 40000  -51.7 -61.1   262   56   29   0.9   0.5   68.2 154.7    41.0      M    M
 38000  -51.2 -60.2   262   58   30  -1.8  -1.0   59.6 139.2    36.4      M    M
 36000  -52.4 -62.3   263   53   27  -2.0  -1.1   48.6 119.5    29.9      M    M
 34000  -53.6 -64.5   265   47   24  -2.0  -1.1   38.8 101.8    23.8      M    M
 32000  -54.1 -65.4   269   40   20  -0.3  -0.2   29.7  85.5    17.9      M    M
 30000  -54.3 -65.7   275   32   16  -0.2  -0.1   21.5  70.8    12.3      M    M
 29000  -53.1 -63.6   278   29   15   8.0   4.4   19.3  66.8    10.8      M    M
 28000  -50.6 -59.1   280   28   15   8.2   4.5   18.6  65.5    10.4      M    M
 27000  -48.2 -54.8   282   27   14   8.2   4.5   18.1  64.5    10.1      M    M
 26000  -45.7 -50.3   285   27   14   8.6   4.7   17.6  63.7     9.9      M    M
 25000  -43.1 -45.6   286   26   13   8.6   4.7   17.1  62.7     9.6      M    M
 24000  -40.5 -40.9   287   26   13   8.6   4.7   16.7  62.0     9.3      M    M
 23000  -38.0 -36.4   289   25   13   7.6   4.2   16.2  61.2     9.1      M    M
 22000  -35.7 -32.3   289   25   13   7.6   4.2   15.4  59.7     8.5      M    M
 21000  -33.4 -28.1   290   24   12   7.7   4.2   14.6  58.3     8.0      M    M
 20000  -30.3 -22.5   289   23   12   8.7   4.7   13.9  57.1     7.5      M    M
 19500  -29.0 -20.2   287   22   12   8.7   4.7   13.7  56.7     7.4      M    M
 19000  -27.7 -17.9   286   22   11   8.7   4.8   13.5  56.4     7.3      M    M
 18500  -26.4 -15.5   285   22   11   8.7   4.8   13.4  56.1     7.2      M    M
 18000  -25.1 -13.2   285   21   11   8.3   4.5   13.2  55.7     7.1      M    M
 17500  -23.9 -11.0   286   21   11   8.3   4.5   12.9  55.3     6.9      M    M
 17000  -22.7  -8.9   287   21   11   7.8   4.3   12.7  54.8     6.7      M    M
 16500  -21.6  -6.9   288   21   11   7.5   4.1   12.3  54.1     6.3      M    M
 16000  -20.4  -4.7   290   21   11   7.4   4.1   11.9  53.4     6.0      M    M
 15500  -19.4  -2.9   292   21   11   7.1   3.9   11.4  52.6     5.7      M    M
 15000  -18.3  -0.9   294   21   11   7.1   3.9   11.0  51.8     5.3      M    M
 14500  -17.3   0.9   294   21   11   6.7   3.6   10.5  50.9     4.9      M    M
 14000  -16.3   2.7   295   21   11   6.6   3.6   10.0  50.0     4.4      M    M
 13500  -15.3   4.5   295   20   11   7.4   4.1    9.6  49.2     4.0      M    M
 13000  -14.2   6.4   295   20   10   7.4   4.1    9.2  48.5     3.7      M    M
 12500  -13.0   8.6   294   20   10   7.4   4.1    8.8  47.8     3.4      M    M
 12000  -11.9  10.6   294   20   10   7.4   4.1    8.4  47.1     3.0      M    M
 11500  -10.8  12.6   293   20   10   7.4   4.0    8.0  46.5     2.7      M    M
 11000   -9.7  14.5   293   20   10   7.4   4.1    7.7  45.8     2.3      M    M
 10500   -8.7  16.3   292   19   10   6.6   3.6    7.2  45.0     1.9      M    M
 10250   -8.2  17.2   292   18    9   6.7   3.7    7.0  44.6     1.7      M    M
 10000   -7.7  18.1   292   18    9   6.7   3.7    6.7  44.1     1.5      M    M
  9750   -7.2  19.0   291   17    9   5.6   3.1    6.5  43.6     1.2      M    M
  9500   -6.8  19.8   291   15    8   4.7   2.6    6.1  43.0     0.8      M    M
  9250   -6.5  20.3   291   14    7   5.0   2.7    5.7  42.3     0.5      M    M
  9000   -6.1  21.0   291   12    6   4.7   2.6    5.3  41.6     0.1      M    M
  8750   -5.8  21.6   290   11    6   4.3   2.4    4.9  40.9    -0.3    240  1.2
  8500   -5.5  22.1   290   10    5   4.2   2.3    4.5  40.1    -0.7    223  1.1
  8250   -5.2  22.6   290    8    4   4.1   2.3    4.0  39.3    -1.1    207  1.1
  8000   -4.9  23.2   290    7    4   4.4   2.4    3.6  38.5    -1.6    190  1.0
  7750   -4.5  23.9   292    7    4   4.7   2.6    3.2  37.8    -2.0    172  0.9
  7500   -4.2  24.4   293    7    3   4.8   2.6    2.8  37.1    -2.4    155  0.8
  7250   -3.8  25.2   295    6    3   4.1   2.2    2.4  36.4    -2.7    137  0.7
  7000   -3.6  25.5   294    6    3   2.5   1.3    1.9  35.5    -3.3    122  0.6
  6750   -3.4  25.9   290    5    3   2.2   1.2    1.4  34.4    -3.8    110  0.6
  6500   -3.3  26.1   285    4    2   1.8   1.0    0.8  33.4    -4.4     98  0.5
  6250   -3.4  25.9   272    4    2  -6.7  -3.7   -0.1  31.9    -5.3     94  0.5
  6000   -4.2  24.4   247    5    2 -13.7  -7.5   -1.7  29.0    -6.9    112  0.6
  5750   -5.1  22.8   233    6    3  -8.6  -4.7   -3.3  26.0    -8.5    131  0.7
  5500   -6.0  21.2   224    8    4 -24.7 -13.6   -5.0  23.0   -10.2    152  0.8

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

           02/10/2010 at 0800 MST          |       02/10/2010 at 1100 MST
                                           |
K index... +6.1                            | K index... +6.8
                                           |
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 -54.4 -65.9  274  39 20   0.9   0.5 | -54.7 -66.5  272  38 19   1.2   0.6
 45000 -53.0 -63.4  266  48 25   0.9   0.5 | -52.9 -63.2  268  48 25   1.2   0.6
 40000 -51.9 -61.4  266  52 27   0.7   0.4 | -52.2 -62.0  266  49 25   0.3   0.2
 38000 -51.5 -60.7  266  53 27  -1.4  -0.7 | -52.0 -61.6  265  48 25  -0.7  -0.4
 36000 -52.8 -63.0  266  48 25  -2.1  -1.2 | -52.6 -62.7  264  46 24  -1.0  -0.5
 34000 -54.1 -65.4  266  43 22  -2.1  -1.2 | -53.2 -63.8  263  44 23  -1.0  -0.5
 32000 -54.6 -66.3  268  36 19  -0.1  -0.1 | -53.8 -64.8  264  37 19  -1.0  -0.6
 30000 -54.6 -66.3  273  29 15   0.1   0.0 | -54.5 -66.1  269  27 14  -1.8  -1.0
 29000 -53.0 -63.4  276  27 14   8.2   4.5 | -53.0 -63.4  271  26 13   8.2   4.5
 28000 -50.5 -58.9  278  27 14   8.3   4.5 | -50.5 -58.9  272  26 13   8.2   4.5
 27000 -48.1 -54.6  279  27 14   8.3   4.5 | -48.0 -54.4  274  26 14   8.2   4.5
 26000 -45.6 -50.1  281  27 14   8.6   4.7 | -45.5 -49.9  276  26 14   8.7   4.8
 25000 -43.0 -45.4  283  27 14   8.5   4.7 | -42.9 -45.2  279  26 13   8.7   4.7
 24000 -40.5 -40.9  286  26 14   8.5   4.7 | -40.4 -40.7  283  26 13   8.7   4.7
 23000 -38.0 -36.4  288  26 13   8.0   4.4 | -37.8 -36.0  286  25 13   8.1   4.4
 22000 -35.5 -31.9  289  24 13   8.1   4.4 | -35.4 -31.7  289  23 12   8.1   4.5
 21000 -33.1 -27.6  290  23 12   8.1   4.4 | -33.0 -27.4  292  22 11   8.1   4.5
 20000 -30.7 -23.3  290  22 11   8.3   4.6 | -30.5 -22.9  292  20 11   8.5   4.7
 19500 -29.4 -20.9  290  21 11   8.3   4.6 | -29.2 -20.6  291  20 10   8.6   4.7
 19000 -28.2 -18.8  290  20 11   8.4   4.6 | -27.9 -18.2  290  19 10   8.6   4.7
 18500 -26.9 -16.4  289  20 10   8.3   4.6 | -26.6 -15.9  288  18  9   8.6   4.7
 18000 -25.7 -14.3  289  19 10   7.9   4.3 | -25.4 -13.7  287  18  9   7.9   4.3
 17500 -24.6 -12.3  289  18 10   7.6   4.2 | -24.2 -11.6  285  17  9   7.5   4.1
 17000 -23.5 -10.3  289  18  9   7.5   4.1 | -23.1  -9.6  284  17  9   7.4   4.0
 16500 -22.4  -8.3  289  18  9   7.2   4.0 | -22.1  -7.8  284  17  9   6.7   3.7
 16000 -20.8  -5.4  291  18  9   7.4   4.1 | -20.6  -5.1  285  16  8   6.9   3.8
 15500 -19.6  -3.3  292  18  9   7.6   4.1 | -19.6  -3.3  288  16  8   7.1   3.9
 15000 -18.5  -1.3  294  18  9   7.5   4.1 | -18.5  -1.3  292  17  9   7.2   3.9
 14500 -17.4   0.7  294  19 10   7.2   3.9 | -17.4   0.7  295  17  9   7.5   4.1
 14000 -16.3   2.7  295  19 10   7.2   4.0 | -16.3   2.7  297  18  9   7.5   4.1
 13500 -15.3   4.5  296  20 11   7.2   4.0 | -15.2   4.6  299  19 10   7.3   4.0
 13000 -14.2   6.4  296  22 11   7.2   4.0 | -14.1   6.6  299  21 11   7.3   4.0
 12500 -13.1   8.4  296  23 12   7.2   3.9 | -13.0   8.6  298  22 11   7.5   4.1
 12000 -12.1  10.2  296  24 12   7.1   3.9 | -11.9  10.6  297  24 12   7.5   4.1
 11500 -11.0  12.2  296  24 12   7.9   4.3 | -10.8  12.6  295  24 13   7.3   4.0
 11000  -9.8  14.4  296  24 12   7.9   4.3 |  -9.8  14.4  294  24 12   7.3   4.0
 10500  -8.8  16.2  296  22 11   6.4   3.5 |  -8.7  16.3  293  23 12   7.2   4.0
 10250  -8.3  17.1  296  21 11   6.6   3.6 |  -8.2  17.2  292  22 11   7.2   4.0
 10000  -7.8  18.0  297  20 10   6.4   3.5 |  -7.6  18.3  292  21 11   7.2   4.0
  9750  -7.3  18.9  297  18  9   5.7   3.1 |  -7.1  19.2  291  20 10   7.2   4.0
  9500  -6.9  19.6  298  16  8   5.3   2.9 |  -6.6  20.1  291  19 10   7.2   3.9
  9250  -6.5  20.3  299  15  8   5.6   3.0 |  -6.0  21.2  291  17  9   7.3   4.0
  9000  -6.1  21.0  300  13  7   5.0   2.7 |  -5.5  22.1  291  16  8   6.8   3.7
  8750  -5.8  21.6  300  12  6   4.2   2.3 |  -5.0  23.0  290  14  7   6.1   3.3
  8500  -5.5  22.1  301  10  5   4.2   2.3 |  -4.6  23.7  290  13  7   6.1   3.3
  8250  -5.2  22.6  301   9  4   4.2   2.3 |  -4.1  24.6  289  12  6   6.0   3.3
  8000  -4.9  23.2  301   7  4   4.1   2.2 |  -3.7  25.3  289  10  5   5.4   3.0
  7750  -4.6  23.7  302   7  4   3.9   2.1 |  -3.3  26.1  288   9  5   4.8   2.6
  7500  -4.3  24.3  303   7  3   4.3   2.4 |  -2.9  26.8  287   8  4   5.3   2.9
  7250  -4.0  24.8  304   6  3   2.9   1.6 |  -2.6  27.3  286   7  3   4.0   2.2
  7000  -3.9  25.0  304   5  3   0.7   0.4 |  -2.3  27.9  283   5  3   2.1   1.1
  6750  -3.8  25.2  304   5  3   1.0   0.5 |  -2.2  28.0  277   4  2   2.2   1.2
  6500  -3.8  25.2  304   4  2  -0.6  -0.3 |  -2.0  28.4  268   3  2   1.4   0.8
  6250  -4.0  24.8  292   4  2  -7.6  -4.2 |  -2.1  28.2  248   3  1  -2.4  -1.3
  6000  -4.8  23.4  260   4  2 -11.0  -6.0 |  -2.4  27.7  218   3  1  -4.5  -2.4
  5750  -5.6  21.9  238   5  3 -10.5  -5.8 |  -2.7  27.1  195   4  2  -3.8  -2.1
  5500  -6.7  19.9  225   6  3 -24.4 -13.4 |  -2.9  26.8  183   4  2   0.0   0.0

           02/10/2010 at 1400 MST          |       02/10/2010 at 1700 MST
                                           |
K index... +10.3                           | K index... +13.0
                                           |
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 -54.3 -65.7  274  37 19   0.6   0.3 | -55.0 -67.0  277  38 19   0.8   0.4
 45000 -53.4 -64.1  271  47 24   0.6   0.3 | -53.8 -64.8  269  43 22   0.8   0.4
 40000 -52.2 -62.0  264  53 27   0.8   0.4 | -52.2 -62.0  268  52 27   1.0   0.6
 38000 -51.8 -61.2  261  55 28  -0.7  -0.4 | -51.7 -61.1  268  55 29  -0.6  -0.3
 36000 -52.5 -62.5  263  53 27  -1.1  -0.6 | -52.2 -62.0  268  52 27  -0.9  -0.5
 34000 -53.1 -63.6  265  51 26  -1.1  -0.6 | -52.7 -62.9  268  49 25  -0.9  -0.5
 32000 -53.8 -64.8  268  42 21  -1.1  -0.6 | -53.2 -63.8  269  40 21  -0.8  -0.4
 30000 -54.5 -66.1  273  27 14  -1.7  -0.9 | -53.7 -64.7  274  29 15  -0.6  -0.3
 29000 -53.0 -63.4  275  25 13   8.1   4.4 | -52.4 -62.3  278  25 13   7.4   4.1
 28000 -50.6 -59.1  277  25 13   8.2   4.5 | -50.1 -58.2  281  24 12   7.5   4.1
 27000 -48.1 -54.6  279  24 13   8.2   4.5 | -47.9 -54.2  285  22 11   7.5   4.1
 26000 -45.6 -50.1  281  24 12   8.8   4.8 | -45.5 -49.9  287  22 11   8.8   4.8
 25000 -43.0 -45.4  281  24 13   8.8   4.8 | -42.9 -45.2  286  22 11   8.7   4.8
 24000 -40.4 -40.7  281  24 13   8.8   4.8 | -40.4 -40.7  285  22 11   8.7   4.8
 23000 -37.8 -36.0  282  24 12   8.1   4.5 | -37.8 -36.0  285  22 11   8.1   4.4
 22000 -35.4 -31.7  284  24 12   8.2   4.5 | -35.4 -31.7  285  22 11   8.1   4.5
 21000 -32.9 -27.2  286  23 12   8.2   4.5 | -32.9 -27.2  284  22 11   8.1   4.5
 20000 -30.4 -22.7  284  21 11   8.7   4.8 | -30.3 -22.5  282  21 11   9.1   5.0
 19500 -29.1 -20.4  282  20 11   8.7   4.8 | -29.0 -20.2  279  21 11   9.1   5.0
 19000 -27.8 -18.0  279  20 10   8.7   4.8 | -27.6 -17.7  276  20 10   9.1   5.0
 18500 -26.5 -15.7  276  19 10   8.7   4.8 | -26.3 -15.3  273  20 10   9.1   5.0
 18000 -25.2 -13.4  272  18  9   7.9   4.4 | -24.9 -12.8  270  19 10   8.5   4.7
 17500 -24.1 -11.4  268  18  9   7.4   4.1 | -23.7 -10.7  266  19 10   8.2   4.5
 17000 -23.0  -9.4  264  17  9   7.3   4.0 | -22.5  -8.5  261  19 10   7.9   4.4
 16500 -22.0  -7.6  263  17  9   6.5   3.5 | -21.5  -6.7  260  19 10   6.0   3.3
 16000 -20.5  -4.9  264  16  8   6.6   3.6 | -20.1  -4.2  258  18  9   6.1   3.3
 15500 -19.6  -3.3  268  16  8   6.6   3.6 | -19.3  -2.7  261  18  9   5.9   3.2
 15000 -18.6  -1.5  272  15  8   6.7   3.7 | -18.4  -1.1  264  17  9   6.0   3.3
 14500 -17.5   0.5  277  16  8   7.6   4.2 | -17.4   0.7  270  16  8   6.5   3.6
 14000 -16.4   2.5  282  16  8   7.6   4.1 | -16.5   2.3  278  16  8   6.4   3.5
 13500 -15.2   4.6  285  17  9   7.7   4.2 | -15.4   4.3  285  16  8   7.7   4.3
 13000 -14.1   6.6  288  19 10   7.7   4.2 | -14.3   6.3  291  17  9   7.6   4.2
 12500 -13.0   8.6  290  21 11   7.8   4.3 | -13.1   8.4  295  18  9   8.1   4.5
 12000 -11.8  10.8  291  22 12   7.8   4.3 | -11.9  10.6  298  20 10   8.1   4.4
 11500 -10.7  12.7  292  24 12   7.7   4.2 | -10.7  12.7  299  21 11   8.2   4.5
 11000  -9.5  14.9  293  24 13   7.7   4.2 |  -9.5  14.9  300  22 12   8.2   4.5
 10500  -8.3  17.1  294  24 13   8.3   4.5 |  -8.3  17.1  300  23 12   8.6   4.7
 10250  -7.7  18.1  295  24 12   8.2   4.5 |  -7.7  18.1  301  22 11   8.5   4.7
 10000  -7.1  19.2  295  24 12   8.2   4.5 |  -7.1  19.2  301  22 11   8.5   4.7
  9750  -6.5  20.3  296  23 12   8.1   4.5 |  -6.4  20.5  302  21 11   8.4   4.6
  9500  -6.0  21.2  297  22 11   8.0   4.4 |  -5.8  21.6  302  20 10   8.3   4.6
  9250  -5.4  22.3  298  20 10   8.2   4.5 |  -5.2  22.6  303  19 10   8.5   4.6
  9000  -4.8  23.4  299  19 10   7.6   4.2 |  -4.6  23.7  304  18  9   8.0   4.4
  8750  -4.3  24.3  301  17  9   6.7   3.7 |  -4.1  24.6  305  17  9   7.4   4.0
  8500  -3.8  25.2  302  15  8   6.6   3.6 |  -3.6  25.5  306  15  8   7.3   4.0
  8250  -3.3  26.1  305  13  7   6.8   3.7 |  -3.0  26.6  307  13  7   7.4   4.1
  8000  -2.9  26.8  307  12  6   5.9   3.2 |  -2.5  27.5  308  11  6   6.3   3.4
  7750  -2.5  27.5  308   9  5   5.1   2.8 |  -2.1  28.2  306   9  5   5.3   2.9
  7500  -2.1  28.2  310   7  4   5.5   3.0 |  -1.7  28.9  304   7  3   5.5   3.0
  7250  -1.6  29.1  313   5  3   4.8   2.7 |  -1.3  29.7  299   4  2   5.6   3.1
  7000  -1.3  29.7  310   3  2   3.8   2.1 |  -0.8  30.6  283   3  2   5.9   3.2
  6750  -1.0  30.2  283   1  1   3.7   2.0 |  -0.4  31.3  252   2  1   6.0   3.3
  6500  -0.7  30.7  181   1  1   3.7   2.0 |   0.1  32.2  218   3  1   5.9   3.3
  6250  -0.4  31.3  164   3  1   2.4   1.3 |   0.5  32.9  199   4  2   4.1   2.3
  6000  -0.3  31.5  169   3  2   1.7   1.0 |   0.7  33.3  194   4  2   2.4   1.3
  5750  -0.2  31.6  172   3  2   1.3   0.7 |   1.0  33.8  191   5  3   4.3   2.4
  5500  -0.1  31.8  176   3  2   3.8   2.1 |   1.2  34.2  188   6  3  -1.6  -0.9
________________________________________________________________________________

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:

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 - 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, cirrostatus, 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.

071806



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