Soaring Guidance
Issued by NWS Pueblo, CO
Issued by NWS Pueblo, CO
501
UXUS97 KPUB 081208
SRGPUB
Soaring Forecast
National Weather Service Pueblo, Colorado
0508 MST Sunday, December 8, 2024
This forecast is for the Air Force Academy for Sunday, December 8, 2024:
If the trigger temperature of 58.8 F/14.9 C is reached...then
Thermal Soaring Index....................... Fair
Maximum rate of lift........................ 534 ft/min (2.7 m/s)
Maximum height of thermals.................. 13480 ft MSL (5847 ft AGL)
Forecast maximum temperature................... 61.0 F/16.6 C
Time of trigger temperature.................... 1030 MST
Time of overdevelopment........................ None
Middle/high clouds during soaring window....... None
Surface winds during soaring window............ Between 20 mph and 30 mph
Height of the -3 thermal index................. 9850 ft MSL (2217 ft AGL)
Thermal soaring outlook for Monday 12/09....... Poor
Wave Soaring Index............................. Not available
Remarks...
Sunrise/Sunset.................... 07:06:14 / 16:36:49 MST
Total possible sunshine........... 9 hr 30 min 35 sec (570 min 35 sec)
Altitude of sun at 11:51:32 MST... 28.17 degrees
Upper air data from numerical model forecast valid on 12/08/2024 at 0500 MST
Freezing level.................. 7634 ft MSL (1 ft AGL)
Additional freezing level....... 12935 ft MSL (5302 ft AGL)
Convective condensation level... 20828 ft MSL (13195 ft AGL)
Lifted condensation level....... 18573 ft MSL (10939 ft AGL)
Lifted index.................... +5.3
K index......................... +11.6
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 -62.5 -80.5 285 23 12 1.9 1.1 M M M M M
45000 -59.8 -75.6 300 26 14 -1.2 -0.6 M M M M M
40000 -62.1 -79.8 315 21 11 -1.5 -0.8 M M M M M
38000 -58.5 -73.3 320 17 9 8.3 4.5 M M M M M
36000 -53.5 -64.3 320 14 7 8.3 4.6 M M M M M
34000 -48.6 -55.5 325 11 6 8.3 4.6 M M M M M
32000 -43.6 -46.5 330 9 5 8.3 4.6 M M M M M
30000 -38.6 -37.5 335 8 4 8.3 4.6 29.9 85.8 10.7 M M
29000 -36.1 -33.0 340 9 5 8.3 4.6 29.3 84.7 10.3 M M
28000 -33.6 -28.5 340 9 5 8.3 4.6 28.8 83.9 10.1 M M
27000 -31.2 -24.2 340 10 5 7.5 4.1 28.3 83.0 9.8 M M
26000 -28.9 -20.0 345 11 5 7.6 4.2 27.4 81.3 9.1 M M
25000 -26.6 -15.9 350 11 6 7.6 4.2 26.6 79.9 8.6 M M
24000 -24.4 -11.9 350 12 6 7.2 4.0 25.9 78.7 8.1 M M
23000 -21.8 -7.2 350 14 7 7.0 3.8 24.6 76.3 7.1 M M
22000 -19.7 -3.5 345 15 8 7.0 3.8 23.6 74.6 6.3 M M
21000 -17.7 0.1 345 16 8 7.1 3.9 22.7 72.9 5.6 M M
20000 -15.6 3.9 345 18 9 7.1 3.9 21.7 71.1 4.7 M M
19500 -14.5 5.9 345 18 9 7.1 3.9 21.3 70.3 4.4 M M
19000 -13.5 7.7 345 19 10 7.1 3.9 20.9 69.6 4.0 M M
18500 -12.4 9.7 340 20 10 7.5 4.1 20.5 68.9 3.7 M M
18000 -11.3 11.7 340 20 10 7.4 4.1 20.1 68.2 3.3 M M
17500 -10.2 13.6 340 20 10 7.4 4.0 19.7 67.5 3.0 M M
17000 -9.1 15.6 340 20 10 7.3 4.0 19.3 66.7 2.6 M M
16500 -8.1 17.4 340 19 10 7.3 4.0 18.9 66.0 2.2 M M
16000 -7.0 19.4 340 19 10 7.1 3.9 18.5 65.2 1.8 M M
15500 -6.0 21.2 340 18 9 7.1 3.9 18.0 64.4 1.4 M M
15000 -4.9 23.2 340 18 9 7.5 4.1 17.6 63.7 1.0 M M
14500 -3.8 25.2 340 17 9 7.6 4.2 17.3 63.1 0.7 M M
14000 -2.6 27.3 340 16 8 7.7 4.2 17.0 62.5 0.4 M M
13500 -1.5 29.3 340 15 8 7.9 4.3 16.6 61.9 0.0 M M
13000 -0.4 31.3 340 14 7 11.0 6.1 16.3 61.3 -0.3 491 2.5
12500 1.0 33.8 335 14 7 5.5 3.0 16.3 61.3 -0.4 434 2.2
12000 2.0 35.6 335 14 7 6.6 3.6 15.8 60.4 -0.8 390 2.0
11750 2.5 36.5 335 14 7 7.3 4.0 15.5 60.0 -1.0 367 1.9
11500 3.1 37.6 335 14 7 6.8 3.7 15.3 59.6 -1.2 343 1.7
11250 3.6 38.5 335 14 7 6.2 3.4 15.1 59.1 -1.5 321 1.6
11000 4.0 39.2 335 14 7 6.3 3.5 14.8 58.7 -1.7 299 1.5
10750 4.5 40.1 335 14 7 5.8 3.2 14.5 58.1 -2.0 278 1.4
10500 4.9 40.8 330 13 7 5.8 3.2 14.2 57.6 -2.3 257 1.3
10250 5.4 41.7 330 13 7 6.4 3.5 13.9 57.1 -2.6 237 1.2
10000 5.9 42.6 330 13 7 6.9 3.8 13.7 56.6 -2.8 214 1.1
9750 6.4 43.5 330 12 6 7.3 4.0 13.5 56.3 -3.0 190 1.0
9500 7.0 44.6 330 12 6 7.6 4.2 13.3 56.0 -3.1 165 0.8
9250 7.6 45.7 325 12 6 7.5 4.1 13.2 55.7 -3.3 139 0.7
9000 8.2 46.8 325 12 6 4.6 2.5 12.9 55.2 -3.5 116 0.6
8750 8.4 47.1 325 11 6 1.9 1.1 12.4 54.3 -4.0 102 0.5
8500 8.4 47.1 325 11 6 -1.7 -0.9 11.7 53.1 -4.7 93 0.5
8250 8.5 47.3 325 11 6 9.5 5.2 11.0 51.8 -5.4 84 0.4
8000 4.9 40.8 305 9 4 -91.3 -50.1 6.0 42.8 -10.4 176 0.9
7750 -0.0 32.0 280 9 5 22.5 12.4 0.3 32.6 -16.1 317 1.6
7500 M M M M M M M M M M M M
7250 M M M M M M M M M M M M
7000 M M M M M M M M M M M M
6750 M M M M M M M M M M M M
* * * * * * Numerical weather prediction model forecast data valid * * * * * *
12/08/2024 at 0800 MST | 12/08/2024 at 1100 MST
|
CAPE... 0.0 LI... +2.7 | CAPE... 0.0 LI... +2.6
CINH... 0.0 K Index... +8.7 | CINH... 0.0 K Index... +10.7
|
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 -61.1 -78.0 265 31 16 3.1 1.7 | -61.2 -78.2 260 45 23 2.9 1.6
45000 -56.8 -70.2 270 38 19 -2.2 -1.2 | -57.0 -70.6 265 54 28 -1.6 -0.9
40000 -61.9 -79.4 290 32 16 -3.5 -1.9 | -62.7 -80.9 265 48 24 -3.8 -2.1
38000 -59.0 -74.2 290 29 15 8.2 4.5 | -60.8 -77.4 265 46 24 8.3 4.6
36000 -54.1 -65.4 285 26 14 8.2 4.5 | -55.2 -67.4 270 46 24 8.3 4.6
34000 -49.1 -56.4 285 25 13 8.5 4.7 | -50.2 -58.4 270 46 24 8.4 4.6
32000 -44.0 -47.2 285 25 13 8.5 4.7 | -45.2 -49.4 275 45 23 8.4 4.6
30000 -39.0 -38.2 290 24 13 8.3 4.6 | -40.2 -40.4 280 43 22 8.1 4.5
29000 -36.5 -33.7 290 23 12 8.3 4.6 | -37.8 -36.0 280 40 21 8.1 4.5
28000 -34.0 -29.2 295 22 11 8.4 4.6 | -35.4 -31.7 280 38 19 8.1 4.5
27000 -31.5 -24.7 295 20 10 7.5 4.1 | -32.9 -27.2 280 35 18 7.6 4.2
26000 -29.3 -20.7 300 19 10 7.5 4.1 | -30.7 -23.3 280 32 17 7.5 4.1
25000 -27.1 -16.8 300 18 9 7.5 4.1 | -28.5 -19.3 285 30 15 7.5 4.1
24000 -24.8 -12.6 305 16 8 7.4 4.0 | -26.2 -15.2 285 27 14 7.5 4.1
23000 -22.7 -8.9 315 17 9 7.2 4.0 | -24.0 -11.2 290 26 13 7.5 4.1
22000 -20.0 -4.0 325 18 9 7.2 4.0 | -21.2 -6.2 295 24 13 7.5 4.1
21000 -17.8 -0.0 325 19 10 7.6 4.2 | -19.0 -2.2 300 23 12 8.2 4.5
20000 -15.5 4.1 330 19 10 7.6 4.2 | -16.5 2.3 300 22 11 8.2 4.5
19500 -14.4 6.1 330 19 10 7.6 4.2 | -15.3 4.5 300 21 11 8.2 4.5
19000 -13.3 8.1 330 19 10 7.7 4.2 | -14.1 6.6 300 20 10 8.2 4.5
18500 -12.2 10.0 330 19 10 7.6 4.2 | -12.9 8.8 305 20 10 7.6 4.2
18000 -11.0 12.2 330 19 10 7.6 4.2 | -11.8 10.8 305 19 10 7.6 4.2
17500 -9.9 14.2 330 19 10 7.6 4.2 | -10.7 12.7 305 18 9 7.5 4.1
17000 -8.8 16.2 330 19 10 7.5 4.1 | -9.6 14.7 305 17 9 7.4 4.0
16500 -7.7 18.1 330 18 10 7.5 4.1 | -8.5 16.7 310 15 8 7.4 4.0
16000 -6.6 20.1 330 18 9 7.3 4.0 | -7.4 18.7 315 14 7 7.2 4.0
15500 -5.5 22.1 330 18 9 7.3 4.0 | -6.3 20.7 315 13 7 7.3 4.0
15000 -4.4 24.1 330 18 9 7.5 4.1 | -5.3 22.5 320 12 6 7.1 3.9
14500 -3.3 26.1 330 17 9 7.5 4.1 | -4.2 24.4 330 11 6 7.0 3.8
14000 -2.2 28.0 330 17 9 7.4 4.1 | -3.2 26.2 335 11 5 6.7 3.7
13500 -1.1 30.0 330 17 9 7.5 4.1 | -2.3 27.9 340 10 5 6.5 3.6
13000 -0.1 31.8 330 16 8 10.6 5.8 | -1.3 29.7 345 10 5 10.2 5.6
12500 1.3 34.3 330 16 8 4.9 2.7 | -0.0 32.0 350 11 6 4.2 2.3
12000 2.2 36.0 325 16 8 6.0 3.3 | 0.8 33.4 355 11 6 5.3 2.9
11750 2.7 36.9 325 16 8 7.4 4.0 | 1.2 34.2 355 12 6 6.0 3.3
11500 3.2 37.8 325 16 8 7.0 3.8 | 1.6 34.9 355 13 7 6.5 3.6
11250 3.7 38.7 325 16 8 6.1 3.4 | 2.1 35.8 355 14 7 6.5 3.6
11000 4.1 39.4 325 16 8 6.3 3.5 | 2.6 36.7 355 15 8 6.6 3.6
10750 4.6 40.3 325 17 9 6.0 3.3 | 3.2 37.8 355 16 8 7.5 4.1
10500 5.0 41.0 325 17 9 6.0 3.3 | 3.8 38.8 355 18 9 8.3 4.5
10250 5.5 41.9 325 17 9 7.1 3.9 | 4.4 39.9 355 19 10 8.8 4.9
10000 6.1 43.0 325 17 9 7.5 4.1 | 5.1 41.2 355 20 10 9.3 5.1
9750 6.6 43.9 325 17 9 6.5 3.6 | 5.8 42.4 350 20 10 8.6 4.7
9500 7.1 44.8 330 17 9 5.8 3.2 | 6.4 43.5 345 20 10 8.7 4.8
9250 7.5 45.5 330 17 9 6.7 3.7 | 7.0 44.6 345 20 10 7.5 4.1
9000 8.0 46.4 330 17 9 5.5 3.0 | 7.5 45.5 340 20 10 4.6 2.5
8750 8.3 46.9 325 17 9 2.2 1.2 | 7.7 45.9 330 19 10 2.4 1.3
8500 8.3 46.9 325 16 8 -1.8 -1.0 | 7.8 46.0 325 18 9 1.9 1.0
8250 8.4 47.1 320 15 8 7.9 4.3 | 8.0 46.4 320 17 9 1.3 0.7
8000 8.8 47.8 315 14 7 -10.2 -5.6 | 8.1 46.6 310 16 8 2.6 1.4
7750 5.7 42.3 300 11 6 -74.9 -41.1 | 8.4 47.1 305 12 6 7.7 4.2
7500 M M M M M M M | M M M M M M M
7250 M M M M M M M | M M M M M M M
7000 M M M M M M M | M M M M M M M
6750 M M M M M M M | M M M M M M M
12/08/2024 at 1400 MST | 12/08/2024 at 1700 MST
|
CAPE... 0.0 LI... +1.8 | CAPE... 0.0 LI... +3.0
CINH... 0.0 K Index... +15.3 | CINH... 0.0 K Index... -30.0
|
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 -61.0 -77.8 255 54 28 3.3 1.8 | -59.6 -75.3 255 56 29 2.6 1.4
45000 -55.8 -68.4 260 65 34 -0.8 -0.5 | -55.7 -68.3 270 75 39 3.3 1.8
40000 -61.9 -79.4 265 67 34 -4.1 -2.2 | -61.1 -78.0 265 82 42 -3.7 -2.0
38000 -60.7 -77.3 265 68 35 7.7 4.2 | -60.3 -76.5 265 83 43 6.3 3.4
36000 -56.1 -69.0 265 70 36 7.7 4.2 | -56.5 -69.7 265 82 42 6.3 3.4
34000 -50.9 -59.6 265 69 36 7.6 4.2 | -52.6 -62.7 265 80 41 7.7 4.2
32000 -46.4 -51.5 270 63 33 7.6 4.2 | -48.0 -54.4 270 71 36 7.7 4.2
30000 -41.7 -43.1 275 57 29 8.1 4.4 | -43.3 -45.9 270 63 32 7.9 4.3
29000 -39.3 -38.7 275 52 27 8.1 4.4 | -41.0 -41.8 270 59 30 7.9 4.3
28000 -36.9 -34.4 275 48 25 8.1 4.4 | -38.6 -37.5 270 55 28 7.9 4.3
27000 -34.5 -30.1 275 44 23 7.9 4.3 | -36.2 -33.2 270 51 26 7.9 4.3
26000 -32.2 -26.0 275 43 22 7.7 4.2 | -33.8 -28.8 270 49 25 7.9 4.3
25000 -29.9 -21.8 275 41 21 7.8 4.3 | -31.4 -24.5 270 47 24 7.9 4.3
24000 -27.6 -17.7 275 39 20 7.7 4.2 | -28.5 -19.3 270 44 23 8.1 4.4
23000 -25.4 -13.7 275 38 19 7.2 3.9 | -26.0 -14.8 275 43 22 8.3 4.5
22000 -23.3 -9.9 275 36 19 7.2 3.9 | -23.5 -10.3 275 41 21 8.3 4.5
21000 -20.6 -5.1 280 34 18 7.3 4.0 | -21.0 -5.8 280 40 20 8.4 4.6
20000 -18.5 -1.3 280 32 17 7.4 4.0 | -18.5 -1.3 280 39 20 8.4 4.6
19500 -17.4 0.7 285 32 16 7.4 4.0 | -17.2 1.0 280 38 20 8.4 4.6
19000 -16.3 2.7 285 31 16 7.4 4.1 | -15.9 3.4 280 38 19 8.4 4.6
18500 -15.3 4.5 285 30 15 6.9 3.8 | -14.7 5.5 285 37 19 8.0 4.4
18000 -14.3 6.3 285 28 15 6.8 3.7 | -13.5 7.7 285 37 19 7.8 4.3
17500 -13.3 8.1 285 27 14 6.9 3.8 | -12.3 9.9 285 36 19 7.8 4.3
17000 -12.2 10.0 285 25 13 7.4 4.1 | -11.2 11.8 285 36 18 7.6 4.2
16500 -11.1 12.0 285 23 12 7.2 4.0 | -10.0 14.0 290 35 18 7.7 4.2
16000 -9.9 14.2 285 22 11 9.1 5.0 | -8.9 16.0 290 35 18 6.8 3.8
15500 -8.5 16.7 280 20 10 9.1 5.0 | -7.9 17.8 290 34 17 6.7 3.7
15000 -7.2 19.0 275 18 9 7.9 4.4 | -6.9 19.6 290 33 17 6.5 3.6
14500 -6.1 21.0 270 16 8 7.2 3.9 | -5.9 21.4 290 31 16 6.4 3.5
14000 -5.1 22.8 265 14 7 6.9 3.8 | -5.0 23.0 295 30 15 6.2 3.4
13500 -4.1 24.6 260 12 6 6.6 3.6 | -4.1 24.6 290 29 15 5.3 2.9
13000 -3.1 26.4 255 10 5 8.5 4.6 | -3.4 25.9 290 28 14 6.7 3.7
12500 -1.9 28.6 255 8 4 5.7 3.1 | -2.4 27.7 290 27 14 3.6 2.0
12000 -1.0 30.2 250 6 3 6.3 3.4 | -2.0 28.4 290 26 14 2.4 1.3
11750 -0.5 31.1 250 5 3 8.4 4.6 | -1.8 28.8 285 26 13 7.2 4.0
11500 0.2 32.4 260 4 2 9.1 5.0 | -1.1 30.0 285 26 13 7.4 4.1
11250 0.9 33.6 265 3 2 8.1 4.4 | -0.9 30.4 285 25 13 2.7 1.5
11000 1.5 34.7 275 3 1 8.3 4.6 | -0.7 30.7 280 25 13 3.5 1.9
10750 2.1 35.8 280 2 1 9.0 4.9 | -0.4 31.3 280 24 12 5.0 2.7
10500 2.8 37.0 280 2 1 9.4 5.1 | -0.0 32.0 280 23 12 6.4 3.5
10250 3.5 38.3 280 2 1 8.1 4.4 | 0.5 32.9 275 22 11 7.7 4.2
10000 4.1 39.4 285 3 2 7.3 4.0 | 1.1 34.0 275 21 11 9.2 5.0
9750 4.6 40.3 285 4 2 5.4 3.0 | 1.7 35.1 270 20 10 8.5 4.7
9500 4.9 40.8 285 6 3 4.4 2.4 | 2.3 36.1 270 19 10 8.0 4.4
9250 5.2 41.4 280 8 4 3.4 1.9 | 2.9 37.2 270 18 9 9.1 5.0
9000 5.4 41.7 280 10 5 2.6 1.4 | 3.7 38.7 270 18 9 10.1 5.5
8750 5.6 42.1 275 11 6 6.0 3.3 | 4.4 39.9 265 17 9 8.1 4.4
8500 6.2 43.2 270 11 5 7.6 4.1 | 4.9 40.8 260 15 8 5.9 3.2
8250 6.7 44.1 265 10 5 7.7 4.2 | 5.4 41.7 255 14 7 9.3 5.1
8000 7.2 45.0 260 9 5 6.1 3.3 | 6.0 42.8 250 12 6 2.0 1.1
7750 7.4 45.3 255 6 3 0.5 0.3 | 5.2 41.4 245 8 4 -21.7 -11.9
7500 M M M M M M M | M M M M M M M
7250 M M M M M M M | M M M M M M M
7000 M M M M M M M | M M M M M M M
6750 M M M M M M M | M M M M M M M
________________________________________________________________________________
This product is issued twice per day, once by approximately 0630 MST/0730 MDT
(1330 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 Air Force Academy
in Colorado Springs, Colorado at
North Latitude: 38 deg 58 min 48.000 sec
West Longitude: 104 deg 49 min 12.000 sec
Elevation: 6572 feet (2003 meters)
and may not be representative of other areas along the Front Range of the
Colorado Rocky Mountains. Note that some elevations in numerical weather
prediction models differ from actual station elevations, which can lead to
data which appear to be below ground. Erroneous data such as these should
not be used.
The content and format of this report as well as the issuance times are subject
to change without prior notice. Comments and suggestions are welcome and should
be directed to one of the addresses or phone numbers shown at the bottom of this
page. To expedite a response to comments, be sure to mention your interest in
the soaring forecast.
DEFINITIONS:
CAPE (Convective Available Potential Energy) - An integrated measure of the
energy available for convective development, also known as the positive
area on a thermodynamic diagram. Units are Joules per kilogram. Larger
values are indicative of greater instability and the possibility of
stronger convective activity, including thunderstorms. Values around or
greater than 1000 suggest the possibility of severe weather should
convective activity develop.
CIN (Convective Inhibition) - An integrated measure of the amount of energy
needed to initiate convective activity, also known as the negative area on
a thermodynamic diagram. Units are Joules per kilogram. The more negative
this number, the more energy is required to initiate convection. This
inhibitive energy can be overcome through surface heating, cooling aloft,
lifting mechanisms (orographic, frontal, gravity waves, etc.)
Convective Condensation Level - The height to which an air parcel possessing the
average saturation mixing ratio in the lowest 4000 feet of the airmass,
if heated sufficiently from below, will rise dry adiabatically until it
just becomes saturated. It estimates the base of cumulus clouds that are
produced by surface heating only.
Convection Temperature (ConvectionT) - The surface temperature required to make
the airmass dry adiabatic up to the given level. It can be considered a
"trigger temperature" for that level.
Freezing Level - The height where the temperature is zero degrees Celsius.
Height of Stable Layer - The height (between 12,000 and 18,000 feet above
mean sea level) where the smallest lapse rate exists. The location and
existence of this feature is important in the generation of mountain
waves.
K Index - A measure of stability which combines the temperature difference
between approximately 5,000 and 18,000 feet above the surface, the amount
of moisture at approximately 5,000 feet above the surface, and a measure
of the dryness at approximately 10,000 feet above the surface. Larger
positive numbers indicate more instability and a greater likelihood of
thunderstorm development. One interpretation of K index values regarding
soaring in the western United States is given in WMO Technical Note 158
and is reproduced in the following table:
below -10 no or weak thermals
-10 to 5 dry thermals or 1/8 cumulus with moderate thermals
5 to 15 good soaring conditions
15 to 20 good soaring conditions with occasional showers
20 to 30 excellent soaring conditions, but increasing
probability of showers and thunderstorms
above 30 more than 60 percent probability of thunderstorms
Lapse Rate - The change with height of the temperature. Negative values indicate
inversions.
Lifted Condensation Level - The height to which an air parcel possessing the
average dew point in the lowest 4000 feet of the airmass and the forecast
maximum temperature must be lifted dry adiabatically to attain saturation.
Lifted Index (LI) - The difference between the environmental temperature at a
level approximately 18,000 feet above the surface and the temperature of
an air parcel lifted dry adiabatically from the surface to its lifted
condensation level and then pseudoadiabatically thereafter to this same
level. The parcel`s initial temperature is the forecast maximum
temperature and its dew point is the average dew point in the lowest 4000
feet of the airmass. Negative values are indicative of instability with
positive values showing stable conditions.
Lift Rate - An experimental estimate of the strength of thermals. It is
computed the same way as the maximum rate of lift but uses the actual
level rather than the maximum height of thermals in the calculation.
Also, none of the empirical adjustments based on cloudiness and K-index
are applied to these calculations.
Maximum Height of Thermals - The height where the dry adiabat through the
forecast maximum temperature intersects the environmental temperature.
Maximum Rate of Lift - An estimate of the maximum strength of thermals. It
is computed from an empirical formula which combines the expected maximum
height of thermals with the difference in the environmental temperatures
between the maximum height of thermals and the temperature 4,000 feet
above the ground. After this computation, further empirical adjustments
are made based on the value of the K-index and the amount and opacity of
middle and high level cloudiness expected between the time of trigger
temperature and the time of overdevelopment.
Middle/High Clouds - The amount and opacity of middle (altostratus, altocumulus)
or high (cirrus, cirrostratus, cirrocumulus) clouds. Broken means that
between 60% and 90% of the sky is covered by the cloud, with overcast
conditions occurring when more than 90% of the sky is covered by the cloud.
Thin implies that the clouds are predominantly transparent, meaning that
some sunlight is reaching the ground, in contrast to opaque which suggests
that little sunlight is reaching the ground.
Potential Height of Wave - The minimum of the following two heights:
1. Level above the height of stable layer (or 14,000 feet if none exists)
where the wind direction changes by 30 degrees or more
2. Level above the height of stable layer (or 14,000 feet if none exists)
where the wind speed no longer increases with height
PVA/NVA - Positive vorticity advection (PVA)/negative vorticity advection (NVA)
on the 500 millibar isobaric surface (approximately 18,000 feet above mean
sea level). Weak PVA has been shown to assist in mountain wave soaring.
Soaring Window - The time between the time the trigger temperature is reached
and the time of overdevelopment.
Thermal Index - The difference between the environmental temperature and the
temperature at a particular level determined by following the dry adiabat
through the forecast maximum temperature up to that level. Negative values
are indicative of thermal lift.
Thermal Soaring Index - An adjective rating (for sailplanes) based on the
computed maximum rate of lift, and the wind speed and middle and high
cloud cover expected during the soaring window (the time of the trigger
temperature and the time of overdevelopment) according to the following:
Maximum rate of lift Adjective Rating
>= 800 fpm Excellent
>= 400 and < 800 fpm Good
>= 200 and < 400 fpm Fair
< 200 fpm Poor
Time of Overdevelopment - The time one or more of the following phenomena,
which essentially shut off thermal lift, is expected to occur:
1. formation of broken to overcast convective cloud cover
2. formation of scattered to numerous downbursts
3. initiation of widespread precipitation
Time of Trigger Temperature - The time the surface temperature is expected to
reach the trigger temperature.
Trigger Temperature - The surface temperature required to make the first 4000
feet of the atmosphere dry adiabatic.
Wave Soaring Index - An empirical, adjective rating (for sailplanes) which
attempts to combine a variety of phenomena important in mountain wave
soaring into a single index number. Objective points are assigned to
these phenomena: wind speed and direction at 14,000 ft MSL, the static
stability in the 12,000-18,000 ft MSL layer, the wind speed gradient above
the stable layer, jet stream location and frontal and upper trough
movements.
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