Soaring Guidance
Issued by NWS Denver/Boulder, CO
Issued by NWS Denver/Boulder, CO
491
UXUS97 KBOU 071228
SRGBOU
Soaring Forecast
National Weather Service Denver/Boulder, Colorado
0624 MDT Tuesday, May 7, 2024
This forecast is for Tuesday, May 7, 2024:
If the trigger temperature of 49.9 F/10.0 C is reached...then
Thermal Soaring Index....................... Good
Maximum rate of lift........................ 835 ft/min (4.2 m/s)
Maximum height of thermals.................. 17029 ft MSL (11764 ft AGL)
Forecast maximum temperature................... 61.0 F/16.6 C
Time of trigger temperature.................... 0745 MDT
Time of overdevelopment........................ None
Middle/high clouds during soaring window....... Broken/overcast thin middle
Surface winds during soaring window............ Between 20 mph and 30 mph
Height of the -3 thermal index................. 13854 ft MSL (8589 ft AGL)
Thermal soaring outlook for Wednesday 05/08.... Good
Wave Soaring Index............................. Poor
Wave Soaring Index trend (to 1800 MDT)......... Little change
Height of stable layer (12-18K ft MSL)......... None
Weak PVA/NVA (through 1800 MDT)................ Neither
Potential height of wave....................... 15084 ft MSL (9819 ft AGL)
Wave soaring outlook for Wednesday 05/08....... Poor
Remarks...
Sunrise/Sunset.................... 05:51:55 / 20:00:04 MDT
Total possible sunshine........... 14 hr 8 min 9 sec (848 min 9 sec)
Altitude of sun at 12:56:00 MDT... 67.32 degrees
Upper air data from numerical model forecast valid on 05/07/2024 at 0600 MDT
Freezing level.................. 8392 ft MSL (3127 ft AGL)
Convective condensation level... 13520 ft MSL (8255 ft AGL)
Lifted condensation level....... 14960 ft MSL (9694 ft AGL)
Lifted index.................... +1.1
K index......................... +0.7
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 -50.1 -58.2 250 31 16 4.4 2.4 M M M M M
45000 -43.5 -46.3 255 45 23 2.9 1.6 M M M M M
40000 -47.0 -52.6 255 63 33 -2.5 -1.4 M M M M M
38000 -48.1 -54.6 260 71 36 0.3 0.2 M M M M M
36000 -48.0 -54.4 265 77 40 0.3 0.1 M M M M M
34000 -47.8 -54.0 270 84 43 0.4 0.2 M M M M M
32000 -46.3 -51.3 275 81 42 2.7 1.5 M M M M M
30000 -44.7 -48.5 280 77 40 2.6 1.4 M M M M M
29000 -43.5 -46.3 280 78 40 4.6 2.5 30.4 86.8 10.8 M M
28000 -42.1 -43.8 280 80 41 4.6 2.5 28.3 83.0 9.4 M M
27000 -40.8 -41.4 285 82 42 4.6 2.5 26.4 79.5 8.0 M M
26000 -38.5 -37.3 285 83 43 8.0 4.4 24.7 76.4 6.7 M M
25000 -36.1 -33.0 285 81 42 8.1 4.4 24.0 75.2 6.3 M M
24000 -33.6 -28.5 285 80 41 8.0 4.4 23.4 74.1 5.9 M M
23000 -31.3 -24.3 285 74 38 7.3 4.0 22.7 72.8 5.4 M M
22000 -29.1 -20.4 285 64 33 7.3 4.0 21.7 71.1 4.7 M M
21000 -27.9 -18.2 280 53 27 7.4 4.0 20.9 69.7 4.0 M M
20000 -24.9 -12.8 280 51 26 6.8 3.7 19.9 67.9 3.2 M M
19500 -23.9 -11.0 280 53 27 6.8 3.7 19.4 66.9 2.8 M M
19000 -22.8 -9.0 280 54 28 6.8 3.7 18.9 66.0 2.4 M M
18500 -21.8 -7.2 275 55 29 6.8 3.7 18.4 65.1 2.8 M M
18000 -20.9 -5.6 275 57 29 5.5 3.0 17.9 64.2 1.5 M M
17500 -20.2 -4.4 275 60 31 4.9 2.7 17.0 62.6 0.8 M M
17000 -19.4 -2.9 275 64 33 5.1 2.8 16.2 61.1 0.0 M M
16500 -18.6 -1.5 280 66 34 6.3 3.4 15.5 59.9 -0.6 996 5.1
16000 -17.7 0.1 280 69 35 6.2 3.4 14.9 58.8 -1.1 953 4.8
15500 -16.7 1.9 280 70 36 6.8 3.7 14.4 57.9 -1.6 910 4.6
15000 -15.7 3.7 280 71 37 6.8 3.7 13.9 57.0 -2.1 865 4.4
14500 -14.7 5.5 280 72 37 7.7 4.2 13.4 56.2 -2.5 819 4.2
14000 -13.5 7.7 280 70 36 8.0 4.4 13.1 55.6 -2.9 769 3.9
13500 -12.3 9.9 280 69 35 8.7 4.8 12.9 55.1 -3.1 719 3.7
13000 -10.9 12.4 280 62 32 9.2 5.1 12.8 55.0 -3.3 664 3.4
12500 -8.9 16.0 280 55 28 9.0 4.9 12.6 54.7 -3.4 580 2.9
12000 -7.6 18.3 280 54 28 9.1 5.0 12.5 54.5 -3.6 525 2.7
11500 -6.3 20.7 280 54 28 8.0 4.4 12.3 54.2 -3.8 472 2.4
11000 -5.1 22.8 285 56 29 8.2 4.5 12.0 53.7 -4.0 421 2.1
10500 -4.1 24.6 285 57 29 5.4 3.0 11.6 52.9 -4.5 376 1.9
10250 -3.7 25.3 285 56 29 5.3 2.9 11.3 52.3 -4.8 356 1.8
10000 -3.2 26.2 285 56 29 7.2 3.9 11.0 51.7 -5.1 336 1.7
9750 -2.7 27.1 285 55 28 7.2 4.0 10.8 51.4 -5.3 312 1.6
9500 -2.2 28.0 285 53 27 5.9 3.2 10.5 50.9 -5.7 292 1.5
9250 -1.8 28.8 285 51 26 6.0 3.3 10.2 50.4 -6.0 272 1.4
9000 -1.4 29.5 285 49 25 7.0 3.8 10.0 49.9 -6.3 252 1.3
8750 -0.8 30.6 285 47 24 8.6 4.7 9.8 49.7 -6.5 227 1.2
8500 -0.2 31.6 285 45 23 8.9 4.9 9.7 49.5 -6.6 200 1.0
8250 0.5 32.9 285 44 22 8.5 4.7 9.7 49.4 -6.7 174 0.9
8000 1.1 34.0 285 42 22 9.8 5.4 9.6 49.3 -6.8 147 0.7
7750 1.9 35.4 285 40 20 9.2 5.1 9.6 49.3 -6.8 117 0.6
7500 2.5 36.5 285 37 19 7.5 4.1 9.5 49.1 -6.9 92 0.5
7250 3.0 37.4 285 35 18 8.0 4.4 9.3 48.8 -7.1 67 0.3
7000 3.6 38.5 285 33 17 7.6 4.2 9.2 48.6 -7.3 43 0.2
6750 4.2 39.6 285 30 16 7.4 4.1 9.0 48.2 -7.5 19 0.1
6500 4.7 40.5 280 27 14 7.9 4.3 8.9 47.9 -7.6 M M
6250 5.3 41.5 280 24 12 6.6 3.6 8.7 47.7 -7.8 M M
6000 5.7 42.3 275 21 11 3.8 2.1 8.3 47.0 -8.2 M M
5750 5.9 42.6 275 18 9 4.0 2.2 7.9 46.2 -8.7 M M
5500 6.1 43.0 265 13 6 0.5 0.3 7.4 45.3 -9.2 M M
* * * * * * Numerical weather prediction model forecast data valid * * * * * *
05/07/2024 at 0900 MDT | 05/07/2024 at 1200 MDT
|
CAPE... 0.0 LI... +2.0 | CAPE... +1.5 LI... +1.5
CINH... 0.0 K Index... +8.4 | CINH... -0.0 K Index... +12.1
|
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 -52.0 -61.6 245 34 17 3.5 1.9 | -52.5 -62.5 235 39 20 2.7 1.5
45000 -46.8 -52.2 245 55 28 2.3 1.3 | -48.5 -55.3 240 64 33 2.0 1.1
40000 -48.2 -54.8 255 56 29 -1.0 -0.6 | -48.5 -55.3 260 58 30 -0.1 -0.0
38000 -48.4 -55.1 260 59 30 1.2 0.6 | -48.1 -54.6 265 60 31 2.5 1.4
36000 -47.6 -53.7 270 68 35 1.2 0.7 | -46.3 -51.3 270 70 36 2.6 1.4
34000 -46.9 -52.4 275 76 39 2.4 1.3 | -44.8 -48.6 270 78 40 2.5 1.4
32000 -44.6 -48.3 275 84 43 3.9 2.1 | -43.4 -46.1 270 85 44 2.4 1.3
30000 -42.3 -44.1 275 92 48 3.8 2.1 | -41.9 -43.4 270 92 47 2.7 1.5
29000 -41.2 -42.2 275 95 49 3.6 2.0 | -40.8 -41.4 270 94 48 4.0 2.2
28000 -40.1 -40.2 275 97 50 3.6 2.0 | -39.6 -39.3 270 95 49 4.0 2.2
27000 -39.0 -38.2 275 99 51 3.7 2.0 | -38.4 -37.1 270 97 50 4.0 2.2
26000 -37.6 -35.7 275 98 51 6.7 3.7 | -37.0 -34.6 270 98 50 5.5 3.0
25000 -35.6 -32.1 275 95 49 6.6 3.6 | -35.4 -31.7 270 96 49 5.5 3.0
24000 -33.6 -28.5 275 92 47 6.6 3.6 | -33.7 -28.7 270 94 48 5.5 3.0
23000 -31.7 -25.1 275 88 46 5.3 2.9 | -32.2 -26.0 270 91 47 4.6 2.5
22000 -30.1 -22.2 275 85 44 5.4 3.0 | -30.7 -23.3 265 85 44 4.7 2.6
21000 -28.5 -19.3 270 82 42 5.5 3.0 | -29.3 -20.7 265 79 41 4.9 2.7
20000 -26.7 -16.1 270 79 41 6.5 3.6 | -26.7 -16.1 260 75 39 8.7 4.7
19500 -25.7 -14.3 270 78 40 6.5 3.6 | -25.4 -13.7 260 74 38 8.6 4.7
19000 -24.7 -12.5 270 77 40 6.6 3.6 | -24.1 -11.4 260 73 38 8.6 4.7
18500 -23.3 -9.9 265 76 39 6.3 3.5 | -22.9 -9.2 260 73 37 8.7 4.8
18000 -22.1 -7.8 265 74 38 9.0 4.9 | -21.6 -6.9 260 71 36 7.7 4.2
17500 -20.8 -5.4 265 72 37 8.7 4.8 | -20.5 -4.9 260 68 35 7.7 4.2
17000 -19.5 -3.1 265 70 36 9.0 4.9 | -19.3 -2.7 265 65 34 7.1 3.9
16500 -18.2 -0.8 265 69 36 9.1 5.0 | -18.3 -0.9 265 61 31 6.6 3.6
16000 -16.8 1.8 270 69 35 8.6 4.7 | -17.4 0.7 270 56 29 6.6 3.6
15500 -15.7 3.7 270 69 35 6.7 3.7 | -16.4 2.5 270 53 27 6.5 3.6
15000 -14.7 5.5 275 70 36 6.8 3.8 | -15.4 4.3 275 51 26 6.4 3.5
14500 -13.8 7.2 280 66 34 5.9 3.2 | -14.4 6.1 275 50 26 7.7 4.2
14000 -12.9 8.8 280 60 31 5.8 3.2 | -13.3 8.1 275 50 26 7.6 4.2
13500 -11.9 10.6 285 55 28 7.0 3.8 | -12.2 10.0 280 50 26 7.2 4.0
13000 -10.8 12.6 285 50 26 6.9 3.8 | -11.1 12.0 280 47 24 7.2 3.9
12500 -9.8 14.4 285 46 24 7.7 4.2 | -10.0 14.0 280 44 23 7.6 4.1
12000 -8.6 16.5 280 42 21 7.8 4.3 | -8.9 16.0 280 40 20 7.6 4.2
11500 -7.5 18.5 280 39 20 7.3 4.0 | -7.8 18.0 275 35 18 8.3 4.5
11000 -6.4 20.5 280 40 21 7.3 4.0 | -6.5 20.3 275 30 16 8.4 4.6
10500 -5.3 22.5 280 41 21 7.4 4.1 | -5.2 22.6 280 25 13 9.7 5.3
10250 -4.8 23.4 280 43 22 7.6 4.2 | -4.5 23.9 280 23 12 10.0 5.5
10000 -4.2 24.4 280 44 22 6.9 3.8 | -3.7 25.3 280 21 11 9.0 5.0
9750 -3.7 25.3 280 44 23 7.9 4.3 | -3.1 26.4 280 20 11 9.4 5.2
9500 -3.1 26.4 280 43 22 9.2 5.1 | -2.3 27.9 280 20 10 10.5 5.8
9250 -2.4 27.7 280 41 21 9.7 5.3 | -1.5 29.3 280 20 10 11.2 6.1
9000 -1.7 28.9 280 40 21 7.3 4.0 | -0.7 30.7 280 19 10 8.9 4.9
8750 -1.2 29.8 280 39 20 7.2 3.9 | -0.1 31.8 280 19 10 9.2 5.1
8500 -0.6 30.9 275 37 19 9.8 5.4 | 0.7 33.3 280 19 10 11.4 6.3
8250 0.1 32.2 275 35 18 8.3 4.6 | 1.5 34.7 280 19 10 11.7 6.4
8000 0.8 33.4 275 33 17 11.7 6.4 | 2.4 36.3 280 18 9 8.3 4.5
7750 1.8 35.2 275 31 16 11.3 6.2 | 2.9 37.2 280 18 9 7.4 4.0
7500 2.4 36.3 275 30 16 8.1 4.4 | 3.6 38.5 280 18 9 10.6 5.8
7250 3.1 37.6 270 29 15 8.5 4.7 | 4.3 39.7 280 18 9 9.1 5.0
7000 3.7 38.7 270 28 15 10.7 5.9 | 5.1 41.2 280 18 9 12.0 6.6
6750 4.6 40.3 270 28 14 11.3 6.2 | 6.0 42.8 280 17 9 11.6 6.4
6500 5.3 41.5 270 27 14 9.2 5.0 | 6.7 44.1 280 17 9 8.4 4.6
6250 6.1 43.0 270 26 13 10.2 5.6 | 7.4 45.3 280 17 9 10.0 5.5
6000 6.9 44.4 270 25 13 11.2 6.2 | 8.2 46.8 280 16 8 10.8 5.9
5750 7.7 45.9 270 23 12 11.2 6.2 | 9.2 48.6 280 16 8 18.1 9.9
5500 8.6 47.5 270 20 10 14.1 7.7 | 11.0 51.8 285 15 8 30.2 16.6
05/07/2024 at 1500 MDT | 05/07/2024 at 1800 MDT
|
CAPE... +108.6 LI... -0.7 | CAPE... +6.1 LI... +0.2
CINH... -1.6 K Index... +17.9 | CINH... -28.1 K Index... +18.2
|
Height Temperature Wnd WndSpd Lapse Rate | Temperature Wnd WndSpd Lapse Rate
ft MSL deg C deg F Dir kt m/s C/km F/kft | deg C deg F Dir kt m/s C/km F/kft
--------------------------------------------------------------------------------
50000 -52.9 -63.2 225 31 16 2.3 1.2 | -53.1 -63.6 245 30 15 2.2 1.2
45000 -49.5 -57.1 245 58 30 1.9 1.0 | -49.9 -57.8 250 52 27 1.6 0.9
40000 -48.0 -54.4 260 59 30 1.0 0.5 | -49.1 -56.4 260 55 28 0.5 0.3
38000 -47.2 -53.0 265 64 33 1.8 1.0 | -48.1 -54.6 260 59 31 3.0 1.7
36000 -46.1 -51.0 270 76 39 1.8 1.0 | -46.3 -51.3 265 68 35 3.0 1.6
34000 -45.0 -49.0 270 87 45 2.2 1.2 | -44.5 -48.1 270 77 39 2.6 1.4
32000 -43.4 -46.1 270 93 48 2.7 1.5 | -43.1 -45.6 265 82 42 2.3 1.2
30000 -41.8 -43.2 265 99 51 2.8 1.6 | -41.7 -43.1 265 87 45 2.3 1.2
29000 -40.8 -41.4 265 99 51 3.3 1.8 | -41.1 -42.0 265 86 44 2.1 1.2
28000 -39.8 -39.6 265 100 51 3.3 1.8 | -40.5 -40.9 265 86 44 2.1 1.2
27000 -38.8 -37.8 265 100 51 3.4 1.9 | -39.8 -39.6 265 85 44 2.3 1.2
26000 -37.5 -35.5 265 99 51 6.0 3.3 | -38.5 -37.3 265 84 43 7.6 4.2
25000 -35.7 -32.3 265 96 50 5.9 3.2 | -36.2 -33.2 260 82 42 7.5 4.1
24000 -34.0 -29.2 265 93 48 5.9 3.2 | -34.0 -29.2 255 80 41 7.5 4.1
23000 -32.3 -26.1 265 88 46 4.7 2.6 | -31.9 -25.4 255 75 39 5.5 3.0
22000 -30.9 -23.6 265 78 40 4.9 2.7 | -30.2 -22.4 250 66 34 5.7 3.1
21000 -29.4 -20.9 265 68 35 5.0 2.7 | -28.6 -19.5 250 56 29 5.7 3.1
20000 -26.9 -16.4 265 59 30 8.1 4.4 | -26.5 -15.7 245 50 26 7.8 4.3
19500 -25.7 -14.3 260 57 29 8.1 4.4 | -24.8 -12.6 245 47 24 7.8 4.3
19000 -24.5 -12.1 260 55 28 8.1 4.4 | -23.6 -10.5 245 46 24 7.9 4.3
18500 -23.3 -9.9 260 52 27 8.1 4.4 | -22.4 -8.3 245 44 23 7.8 4.3
18000 -22.1 -7.8 260 51 26 8.2 4.5 | -21.2 -6.2 245 43 22 8.3 4.6
17500 -20.9 -5.6 265 50 26 8.2 4.5 | -20.0 -4.0 245 42 22 8.3 4.6
17000 -19.6 -3.3 265 49 25 8.1 4.5 | -18.8 -1.8 245 42 22 8.1 4.4
16500 -18.4 -1.1 265 47 24 8.1 4.5 | -17.6 0.3 250 43 22 8.0 4.4
16000 -17.2 1.0 265 45 23 8.1 4.5 | -16.4 2.5 250 43 22 8.1 4.5
15500 -16.0 3.2 265 43 22 8.2 4.5 | -15.1 4.8 250 43 22 8.4 4.6
15000 -14.8 5.4 265 41 21 8.2 4.5 | -13.9 7.0 250 42 21 8.4 4.6
14500 -13.6 7.5 265 39 20 8.2 4.5 | -12.7 9.1 250 41 21 8.0 4.4
14000 -12.4 9.7 265 36 18 8.1 4.5 | -11.5 11.3 250 40 20 8.0 4.4
13500 -11.2 11.8 265 33 17 8.5 4.7 | -10.3 13.5 250 38 20 8.8 4.8
13000 -9.9 14.2 265 30 15 8.5 4.7 | -9.0 15.8 250 36 18 8.8 4.8
12500 -8.6 16.5 265 27 14 8.8 4.8 | -7.7 18.1 250 34 18 8.1 4.4
12000 -7.3 18.9 265 26 13 8.8 4.8 | -6.5 20.3 255 36 19 7.9 4.4
11500 -6.0 21.2 270 25 13 9.2 5.0 | -5.2 22.6 255 36 19 9.0 4.9
11000 -4.6 23.7 270 22 12 9.2 5.1 | -3.9 25.0 255 31 16 9.2 5.1
10500 -3.2 26.2 270 20 10 9.6 5.3 | -2.6 27.3 255 28 14 8.0 4.4
10250 -2.5 27.5 270 19 10 9.6 5.3 | -2.0 28.4 255 27 14 7.8 4.3
10000 -1.8 28.8 275 19 10 8.7 4.8 | -1.4 29.5 260 27 14 7.8 4.3
9750 -1.2 29.8 275 19 10 9.5 5.2 | -0.8 30.6 265 28 14 8.4 4.6
9500 -0.4 31.3 280 18 9 10.8 5.9 | -0.2 31.6 265 28 14 8.9 4.9
9250 0.4 32.7 280 18 9 11.7 6.4 | 0.5 32.9 270 28 14 9.7 5.3
9000 1.3 34.3 280 18 9 8.4 4.6 | 1.2 34.2 275 28 14 6.6 3.6
8750 1.8 35.2 280 18 9 8.5 4.7 | 1.6 34.9 275 28 14 6.4 3.5
8500 2.6 36.7 285 18 9 11.7 6.4 | 2.2 36.0 275 28 14 9.2 5.0
8250 3.4 38.1 285 17 9 11.8 6.5 | 2.8 37.0 280 28 15 8.8 4.8
8000 4.3 39.7 285 17 9 8.4 4.6 | 3.5 38.3 280 29 15 7.6 4.2
7750 4.8 40.6 285 17 9 7.2 3.9 | 4.0 39.2 285 29 15 6.2 3.4
7500 5.5 41.9 285 17 9 10.1 5.6 | 4.4 39.9 285 27 14 6.8 3.7
7250 6.2 43.2 285 17 9 8.9 4.9 | 4.9 40.8 290 25 13 6.2 3.4
7000 6.9 44.4 285 17 9 10.7 5.9 | 5.4 41.7 290 24 12 8.2 4.5
6750 7.7 45.9 290 17 9 10.9 6.0 | 6.1 43.0 290 22 11 10.0 5.5
6500 8.5 47.3 290 17 9 9.3 5.1 | 6.8 44.2 295 21 11 9.2 5.0
6250 9.2 48.6 290 16 8 10.3 5.6 | 7.5 45.5 295 20 10 9.6 5.3
6000 10.0 50.0 290 16 8 11.7 6.4 | 8.3 46.9 295 19 10 10.2 5.6
5750 11.1 52.0 290 16 8 18.2 10.0 | 9.1 48.4 295 18 9 11.9 6.5
5500 12.8 55.0 290 14 7 27.1 14.9 | 10.0 50.0 295 15 8 14.2 7.8
________________________________________________________________________________
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.
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