Soaring Guidance
Issued by NWS Denver/Boulder, CO
Issued by NWS Denver/Boulder, CO
598
UXUS97 KBOU 141216
SRGBOU
Soaring Forecast
National Weather Service Denver/Boulder, Colorado
0512 MST Friday, November 14, 2025
This forecast is for Friday, November 14, 2025:
If the trigger temperature of 70.8 F/21.5 C is reached...then
Thermal Soaring Index....................... Fair
Maximum rate of lift........................ 328 ft/min (1.7 m/s)
Maximum height of thermals.................. 11836 ft MSL (6516 ft AGL)
Forecast maximum temperature................... 74.0 F/23.8 C
Time of trigger temperature.................... 1145 MST
Time of overdevelopment........................ None
Middle/high clouds during soaring window....... Overcast opaque high
Surface winds during soaring window............ 20 mph or less
Height of the -3 thermal index................. 8046 ft MSL (2726 ft AGL)
Thermal soaring outlook for Saturday 11/15..... Good
Wave Soaring Index............................. Poor
Wave Soaring Index trend (to 1700 MST)......... Little change
Height of stable layer (12-18K ft MSL)......... None
Weak PVA/NVA (through 1700 MST)................ Neither
Potential height of wave....................... 40205 ft MSL (34885 ft AGL)
Wave soaring outlook for Saturday 11/15........ Poor
Remarks...
Sunrise/Sunset.................... 06:43:38 / 16:44:16 MST
Total possible sunshine........... 10 hr 0 min 38 sec (600 min 38 sec)
Altitude of sun at 11:43:57 MST... 31.68 degrees
Upper air data from numerical model forecast valid on 11/14/2025 at 0500 MST
Freezing level.................. 13665 ft MSL (8345 ft AGL)
Convective condensation level... 22046 ft MSL (16726 ft AGL)
Lifted condensation level....... 17905 ft MSL (12585 ft AGL)
Lifted index.................... +7.1
K index......................... -9.7
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 -64.8 -84.6 265 48 25 2.1 1.1 M M M M M
45000 -61.7 -79.1 265 66 34 1.8 1.0 M M M M M
40000 -58.8 -73.8 275 76 39 5.1 2.8 M M M M M
38000 -54.2 -65.6 275 72 37 7.7 4.2 M M M M M
36000 -49.5 -57.1 275 69 36 7.7 4.2 M M M M M
34000 -44.7 -48.5 275 64 33 8.2 4.5 M M M M M
32000 -39.8 -39.6 275 58 30 8.2 4.5 M M M M M
30000 -34.4 -29.9 275 51 27 7.9 4.3 41.2 106.2 13.6 M M
29000 -32.1 -25.8 275 49 25 7.9 4.3 40.5 104.9 13.2 M M
28000 -29.7 -21.5 275 46 24 7.9 4.3 39.9 103.8 12.9 M M
27000 -27.4 -17.3 275 45 23 7.6 4.2 39.1 102.3 12.4 M M
26000 -25.1 -13.2 275 43 22 7.7 4.2 38.2 100.8 11.8 M M
25000 -22.8 -9.0 275 42 22 7.7 4.2 37.5 99.5 11.4 M M
24000 -20.6 -5.1 275 40 21 7.6 4.2 36.7 98.1 10.9 M M
23000 -18.3 -0.9 275 38 20 7.6 4.2 35.9 96.6 10.3 M M
22000 -16.0 3.2 275 36 18 7.6 4.2 35.2 95.4 9.9 M M
21000 -13.8 7.2 275 34 17 7.0 3.8 34.3 93.7 9.2 M M
20000 -11.7 10.9 275 32 16 7.0 3.8 33.3 91.9 8.4 M M
19500 -10.7 12.7 275 31 16 6.9 3.8 32.8 91.1 8.1 M M
19000 -9.7 14.5 275 30 15 6.6 3.6 32.4 90.3 7.8 M M
18500 -8.8 16.2 275 28 15 5.8 3.2 31.7 89.1 7.2 M M
18000 -7.9 17.8 275 27 14 5.8 3.2 31.1 87.9 6.7 M M
17500 -7.0 19.4 275 26 13 5.9 3.2 30.4 86.7 6.1 M M
17000 -6.1 21.0 275 25 13 5.9 3.2 29.7 85.5 5.6 M M
16500 -5.3 22.5 275 23 12 5.8 3.2 29.1 84.4 5.0 M M
16000 -4.0 24.8 275 22 11 5.8 3.2 28.1 82.5 4.2 M M
15500 -3.1 26.4 280 21 11 5.9 3.2 27.4 81.4 3.6 M M
15000 -2.3 27.9 280 20 10 5.9 3.3 26.8 80.2 3.0 M M
14500 -1.4 29.5 280 20 10 6.1 3.3 26.2 79.1 2.4 M M
14000 -0.5 31.1 280 19 10 6.5 3.6 25.6 78.1 1.9 M M
13500 0.5 32.9 280 18 9 6.5 3.6 25.1 77.1 1.4 M M
13000 1.4 34.5 285 17 9 7.0 3.8 24.6 76.2 0.9 M M
12500 2.5 36.5 285 16 8 6.9 3.8 24.1 75.4 0.5 M M
12000 3.5 38.3 285 15 8 7.7 4.2 23.7 74.7 0.1 M M
11500 4.6 40.3 285 15 8 7.6 4.2 23.4 74.1 -0.3 491 2.5
11000 5.8 42.4 285 14 7 8.1 4.5 23.1 73.5 -0.6 442 2.2
10500 7.0 44.6 285 15 8 9.0 4.9 22.8 73.0 -0.8 392 2.0
10250 7.6 45.7 285 15 8 4.4 2.4 22.7 72.8 -1.0 367 1.9
10000 7.8 46.0 285 15 7 5.2 2.8 22.1 71.8 -1.5 354 1.8
9750 8.4 47.1 285 15 8 10.1 5.5 22.0 71.7 -1.6 326 1.7
9500 9.1 48.4 285 16 8 9.5 5.2 22.0 71.6 -1.7 299 1.5
9250 9.7 49.5 285 17 9 5.9 3.2 21.9 71.5 -1.7 272 1.4
9000 10.0 50.0 285 17 9 5.5 3.0 21.5 70.7 -2.2 256 1.3
8750 10.6 51.1 285 18 9 9.0 5.0 21.4 70.5 -2.3 230 1.2
8500 11.3 52.3 285 19 10 7.9 4.3 21.2 70.2 -2.4 205 1.0
8250 11.8 53.2 285 19 10 5.7 3.1 21.0 69.9 -2.6 182 0.9
8000 12.1 53.8 285 20 10 4.9 2.7 20.7 69.2 -3.0 164 0.8
7750 12.6 54.7 285 20 10 7.4 4.1 20.4 68.7 -3.3 143 0.7
7500 13.1 55.6 280 19 10 6.6 3.6 20.2 68.4 -3.5 119 0.6
7250 13.5 56.3 280 19 10 4.2 2.3 19.9 67.8 -3.9 100 0.5
7000 13.8 56.8 280 18 9 3.6 2.0 19.4 67.0 -4.3 84 0.4
6750 14.1 57.4 275 17 9 6.0 3.3 19.0 66.2 -4.7 67 0.3
6500 14.5 58.1 270 15 8 1.3 0.7 18.7 65.6 -5.1 48 0.2
6250 14.2 57.6 265 12 6 -5.2 -2.8 17.7 63.8 -6.1 49 0.2
6000 14.0 57.2 255 10 5 -0.7 -0.4 16.7 62.0 -7.1 49 0.2
5750 13.8 56.8 245 9 4 -11.2 -6.1 15.7 60.3 -8.1 49 0.2
5500 11.8 53.2 230 8 4 -43.8 -24.0 13.0 55.4 -10.8 101 0.5
* * * * * * Numerical weather prediction model forecast data valid * * * * * *
11/14/2025 at 0800 MST | 11/14/2025 at 1100 MST
|
CAPE... 0.0 LI... +8.0 | CAPE... 0.0 LI... +7.2
CINH... -0.0 K Index... -9.7 | CINH... 0.0 K Index... -5.2
|
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 -65.1 -85.2 265 54 28 0.9 0.5 | -65.2 -85.4 260 58 30 -0.4 -0.2
45000 -63.4 -82.1 265 75 39 2.8 1.6 | -64.9 -84.8 265 80 41 3.8 2.1
40000 -58.8 -73.8 275 69 36 6.2 3.4 | -58.8 -73.8 270 67 35 6.3 3.5
38000 -54.2 -65.6 270 64 33 7.7 4.2 | -54.3 -65.7 270 66 34 7.5 4.1
36000 -49.6 -57.3 270 60 31 7.7 4.2 | -49.9 -57.8 270 65 33 7.5 4.1
34000 -44.7 -48.5 265 57 29 8.4 4.6 | -44.9 -48.8 265 61 32 8.7 4.8
32000 -39.7 -39.5 260 54 28 8.4 4.6 | -39.7 -39.5 265 57 29 8.7 4.8
30000 -34.8 -30.6 260 51 26 7.9 4.3 | -34.7 -30.5 260 55 28 8.2 4.5
29000 -31.9 -25.4 260 48 24 7.9 4.4 | -31.7 -25.1 260 54 28 8.2 4.5
28000 -29.5 -21.1 260 45 23 7.9 4.3 | -29.2 -20.6 260 54 28 8.2 4.5
27000 -27.2 -17.0 260 44 22 7.6 4.2 | -27.1 -16.8 260 52 27 6.9 3.8
26000 -24.9 -12.8 260 42 22 7.6 4.2 | -25.1 -13.2 260 51 26 6.9 3.8
25000 -22.7 -8.9 260 41 21 7.7 4.2 | -23.0 -9.4 260 49 25 6.9 3.8
24000 -20.4 -4.7 260 40 21 7.8 4.3 | -20.9 -5.6 260 47 24 7.5 4.1
23000 -18.0 -0.4 260 39 20 7.8 4.3 | -18.6 -1.5 260 47 24 7.5 4.1
22000 -15.7 3.7 260 39 20 7.9 4.3 | -16.4 2.5 255 46 24 7.5 4.1
21000 -13.4 7.9 265 38 19 7.4 4.1 | -14.1 6.6 255 44 23 7.9 4.3
20000 -11.2 11.8 265 36 18 7.4 4.1 | -11.7 10.9 255 41 21 7.9 4.3
19500 -10.1 13.8 265 35 18 7.4 4.1 | -10.6 12.9 255 40 21 7.9 4.3
19000 -9.0 15.8 270 34 17 7.1 3.9 | -9.4 15.1 255 39 20 7.6 4.2
18500 -7.9 17.8 270 33 17 6.8 3.7 | -8.3 17.1 260 37 19 7.1 3.9
18000 -6.9 19.6 270 32 16 6.9 3.8 | -7.2 19.0 260 34 18 7.2 3.9
17500 -6.0 21.2 270 30 16 5.9 3.2 | -6.2 20.8 260 32 17 6.5 3.6
17000 -5.1 22.8 275 29 15 5.9 3.2 | -5.2 22.6 260 30 16 6.5 3.6
16500 -4.2 24.4 275 27 14 5.6 3.1 | -4.2 24.4 265 29 15 6.3 3.4
16000 -3.4 25.9 275 26 13 5.3 2.9 | -3.3 26.1 265 27 14 6.0 3.3
15500 -2.6 27.3 280 25 13 5.3 2.9 | -1.9 28.6 270 23 12 6.0 3.3
15000 -1.5 29.3 280 22 11 5.0 2.7 | -1.0 30.2 270 22 11 6.1 3.3
14500 -0.8 30.6 280 20 11 5.3 2.9 | -0.1 31.8 270 20 10 6.0 3.3
14000 0.1 32.2 285 19 10 6.1 3.3 | 0.8 33.4 275 19 10 6.0 3.3
13500 1.0 33.8 285 17 9 6.2 3.4 | 1.7 35.1 275 17 9 6.1 3.3
13000 2.0 35.6 285 17 9 7.5 4.1 | 2.6 36.7 275 16 8 6.5 3.6
12500 3.1 37.6 290 16 8 7.4 4.1 | 3.6 38.5 275 16 8 6.4 3.5
12000 4.1 39.4 290 16 8 7.1 3.9 | 4.5 40.1 280 15 8 6.7 3.7
11500 5.2 41.4 290 17 9 7.1 3.9 | 5.5 41.9 275 15 8 6.7 3.7
11000 6.2 43.2 285 17 9 7.0 3.9 | 6.5 43.7 275 15 8 7.1 3.9
10500 7.2 45.0 285 18 9 7.5 4.1 | 7.5 45.5 275 15 8 7.8 4.3
10250 7.7 45.9 285 18 9 3.2 1.8 | 8.0 46.4 275 15 8 3.9 2.1
10000 7.8 46.0 280 17 9 5.0 2.7 | 8.2 46.8 275 14 7 4.9 2.7
9750 8.5 47.3 280 17 9 9.7 5.3 | 8.8 47.8 275 15 7 9.5 5.2
9500 9.1 48.4 280 17 9 8.8 4.8 | 9.5 49.1 275 15 7 8.9 4.9
9250 9.7 49.5 280 17 9 4.8 2.6 | 10.1 50.2 275 15 8 5.2 2.9
9000 9.9 49.8 280 17 9 5.0 2.7 | 10.3 50.5 275 15 8 5.1 2.8
8750 10.5 50.9 280 17 9 8.9 4.9 | 10.9 51.6 275 15 8 8.9 4.9
8500 11.1 52.0 280 17 9 7.4 4.1 | 11.5 52.7 275 16 8 7.7 4.2
8250 11.6 52.9 280 17 9 5.3 2.9 | 12.0 53.6 275 15 8 5.8 3.2
8000 11.9 53.4 275 18 9 4.8 2.6 | 12.4 54.3 275 14 7 5.4 3.0
7750 12.4 54.3 275 18 9 7.6 4.1 | 12.9 55.2 270 13 7 8.0 4.4
7500 13.0 55.4 275 17 9 6.6 3.6 | 13.5 56.3 270 12 6 7.4 4.0
7250 13.3 55.9 275 16 8 4.1 2.2 | 14.0 57.2 270 11 6 5.6 3.1
7000 13.6 56.5 270 15 8 3.9 2.2 | 14.4 57.9 265 10 5 5.4 3.0
6750 14.0 57.2 270 14 7 5.8 3.2 | 14.8 58.6 260 9 5 8.2 4.5
6500 14.3 57.7 260 12 6 1.0 0.6 | 15.5 59.9 260 8 4 7.9 4.3
6250 14.1 57.4 255 11 5 -4.8 -2.6 | 16.0 60.8 255 7 4 6.0 3.3
6000 13.8 56.8 245 9 5 -1.1 -0.6 | 16.4 61.5 250 6 3 5.9 3.2
5750 13.6 56.5 230 8 4 -9.3 -5.1 | 16.9 62.4 240 5 3 8.4 4.6
5500 12.0 53.6 225 7 4 -32.8 -18.0 | 17.8 64.0 240 5 2 16.2 8.9
11/14/2025 at 1400 MST | 11/14/2025 at 1700 MST
|
CAPE... 0.0 LI... +6.6 | CAPE... 0.0 LI... +6.1
CINH... -0.0 K Index... +0.5 | CINH... -0.2 K Index... +6.6
|
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 -65.7 -86.3 265 58 30 -0.4 -0.2 | -66.1 -87.0 270 56 29 0.5 0.3
45000 -65.3 -85.5 265 80 41 4.4 2.4 | -64.5 -84.1 265 71 37 4.1 2.3
40000 -58.3 -72.9 260 70 36 6.6 3.6 | -58.0 -72.4 260 72 37 6.7 3.7
38000 -53.8 -64.8 260 70 36 7.5 4.1 | -53.5 -64.3 260 71 37 7.6 4.2
36000 -49.3 -56.7 260 70 36 7.5 4.1 | -48.9 -56.0 260 70 36 7.6 4.2
34000 -44.6 -48.3 260 68 35 8.0 4.4 | -44.2 -47.6 260 68 35 8.2 4.5
32000 -39.8 -39.6 260 65 33 8.0 4.4 | -39.2 -38.6 260 67 34 8.2 4.5
30000 -34.9 -30.8 260 61 31 8.4 4.6 | -34.4 -29.9 255 64 33 8.2 4.5
29000 -31.8 -25.2 260 58 30 8.4 4.6 | -31.3 -24.3 255 62 32 8.2 4.5
28000 -29.3 -20.7 260 56 29 8.4 4.6 | -28.9 -20.0 255 61 31 8.2 4.5
27000 -27.0 -16.6 260 55 28 7.5 4.1 | -26.7 -16.1 255 59 30 7.3 4.0
26000 -24.8 -12.6 260 54 28 7.5 4.1 | -24.5 -12.1 255 57 30 7.3 4.0
25000 -22.6 -8.7 260 53 27 7.5 4.1 | -22.3 -8.1 255 56 29 7.4 4.0
24000 -20.4 -4.7 255 52 27 7.1 3.9 | -20.2 -4.4 255 54 28 7.1 3.9
23000 -18.4 -1.1 255 50 26 7.1 3.9 | -18.1 -0.6 255 53 27 7.1 3.9
22000 -16.3 2.7 255 49 25 7.1 3.9 | -16.0 3.2 255 51 26 7.1 3.9
21000 -14.1 6.6 250 47 24 7.5 4.1 | -13.9 7.0 255 50 26 7.1 3.9
20000 -11.9 10.6 250 45 23 7.5 4.1 | -11.8 10.8 255 48 25 7.2 3.9
19500 -10.8 12.6 250 43 22 7.5 4.1 | -10.7 12.7 255 47 24 7.2 3.9
19000 -9.7 14.5 250 42 22 7.5 4.1 | -9.7 14.5 260 46 24 7.0 3.9
18500 -8.5 16.7 250 41 21 7.6 4.2 | -8.7 16.3 260 45 23 6.7 3.7
18000 -7.4 18.7 250 39 20 7.7 4.2 | -7.7 18.1 260 44 23 6.8 3.7
17500 -6.3 20.7 250 38 19 6.6 3.6 | -6.7 19.9 260 43 22 6.0 3.3
17000 -5.3 22.5 255 36 19 6.5 3.6 | -5.8 21.6 260 41 21 6.0 3.3
16500 -4.3 24.3 255 35 18 6.1 3.4 | -4.9 23.2 260 40 20 5.9 3.2
16000 -3.5 25.7 255 33 17 5.6 3.1 | -4.1 24.6 260 37 19 5.8 3.2
15500 -2.2 28.0 260 30 15 5.6 3.1 | -2.7 27.1 260 32 17 6.0 3.3
15000 -1.4 29.5 260 27 14 5.7 3.1 | -1.8 28.8 255 29 15 6.1 3.4
14500 -0.5 31.1 260 24 12 5.9 3.2 | -0.9 30.4 255 25 13 6.3 3.4
14000 0.4 32.7 260 22 11 6.7 3.7 | 0.1 32.2 255 23 12 6.7 3.7
13500 1.4 34.5 265 20 10 6.6 3.6 | 1.1 34.0 250 20 11 6.7 3.7
13000 2.4 36.3 265 18 9 7.2 4.0 | 2.1 35.8 250 18 10 6.8 3.7
12500 3.5 38.3 265 17 9 7.1 3.9 | 3.1 37.6 250 17 9 6.7 3.7
12000 4.6 40.3 265 16 8 7.5 4.1 | 4.1 39.4 250 15 8 7.9 4.3
11500 5.7 42.3 265 15 8 7.5 4.1 | 5.3 41.5 245 13 7 7.7 4.2
11000 6.8 44.2 265 14 7 7.4 4.1 | 6.5 43.7 245 12 6 8.5 4.7
10500 7.9 46.2 265 13 7 8.1 4.5 | 7.7 45.9 245 10 5 9.1 5.0
10250 8.4 47.1 265 12 6 4.8 2.6 | 8.4 47.1 245 10 5 5.7 3.1
10000 8.7 47.7 265 12 6 6.0 3.3 | 8.7 47.7 245 9 4 6.8 3.7
9750 9.4 48.9 265 11 6 10.0 5.5 | 9.4 48.9 245 8 4 10.9 6.0
9500 10.1 50.2 265 10 5 9.8 5.4 | 10.2 50.4 245 7 4 10.4 5.7
9250 10.7 51.3 265 9 5 6.7 3.7 | 10.9 51.6 245 7 4 7.5 4.1
9000 11.1 52.0 265 8 4 6.5 3.6 | 11.4 52.5 245 6 3 7.4 4.1
8750 11.8 53.2 260 7 4 9.8 5.4 | 12.1 53.8 240 5 3 10.5 5.8
8500 12.5 54.5 260 7 3 9.0 4.9 | 12.9 55.2 240 5 2 9.7 5.3
8250 13.1 55.6 255 6 3 6.8 3.7 | 13.6 56.5 235 4 2 7.5 4.1
8000 13.5 56.3 260 4 2 6.7 3.7 | 14.1 57.4 235 3 1 7.2 4.0
7750 14.2 57.6 260 3 2 9.8 5.4 | 14.7 58.5 220 2 1 9.9 5.4
7500 14.9 58.8 255 3 1 9.1 5.0 | 15.4 59.7 205 2 1 9.0 4.9
7250 15.5 59.9 255 2 1 6.7 3.7 | 16.0 60.8 185 2 1 6.7 3.7
7000 15.9 60.6 270 1 0 6.4 3.5 | 16.5 61.7 160 2 1 6.2 3.4
6750 16.5 61.7 000 0 0 11.0 6.0 | 17.0 62.6 140 2 1 9.1 5.0
6500 17.4 63.3 260 1 0 11.0 6.0 | 17.7 63.9 140 3 1 8.2 4.5
6250 18.1 64.6 000 0 0 8.2 4.5 | 18.2 64.8 130 3 2 5.1 2.8
6000 18.7 65.7 000 0 0 8.5 4.7 | 18.6 65.5 125 4 2 6.9 3.8
5750 19.4 66.9 050 1 0 10.4 5.7 | 19.1 66.4 120 4 2 2.7 1.5
5500 20.4 68.7 000 0 0 15.1 8.3 | 18.7 65.7 120 3 1 -12.8 -7.0
________________________________________________________________________________
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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