Soaring Guidance
Issued by NWS Pueblo, CO
Issued by NWS Pueblo, CO
081
UXUS97 KPUB 221210
SRGPUB
Soaring Forecast
National Weather Service Pueblo, Colorado
0610 MDT Saturday, June 22, 2024
This forecast is for the Air Force Academy for Saturday, June 22, 2024:
If the trigger temperature of 73.4 F/23.0 C is reached...then
Thermal Soaring Index....................... Good
Maximum rate of lift........................ 725 ft/min (3.7 m/s)
Maximum height of thermals.................. 19616 ft MSL (12008 ft AGL)
Forecast maximum temperature................... 85.0 F/29.9 C
Time of trigger temperature.................... 0915 MDT
Time of overdevelopment........................ 1700 MDT
Middle/high clouds during soaring window....... Broken/overcast opaque middle
Surface winds during soaring window............ 20 mph or less
Height of the -3 thermal index................. 16580 ft MSL (8972 ft AGL)
Thermal soaring outlook for Sunday 06/23....... Good
Wave Soaring Index............................. Not available
Remarks...
Sunrise/Sunset.................... 05:34:23 / 20:28:35 MDT
Total possible sunshine........... 14 hr 54 min 13 sec (894 min 13 sec)
Altitude of sun at 13:01:29 MDT... 74.44 degrees
Upper air data from numerical model forecast valid on 06/22/2024 at 0600 MDT
Freezing level.................. 16231 ft MSL (8623 ft AGL)
Convective condensation level... 22585 ft MSL (14977 ft AGL)
Lifted condensation level....... 21027 ft MSL (13419 ft AGL)
Lifted index.................... +1.7
K index......................... -3.0
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 -62.3 -80.1 245 44 22 4.5 2.5 M M M M M
45000 -55.7 -68.3 250 65 33 3.8 2.1 M M M M M
40000 -49.2 -56.6 255 86 44 7.0 3.9 M M M M M
38000 -45.0 -49.0 250 82 42 7.0 3.8 M M M M M
36000 -40.8 -41.4 245 78 40 7.1 3.9 M M M M M
34000 -35.9 -32.6 240 67 35 7.3 4.0 M M M M M
32000 -31.5 -24.7 240 57 30 7.7 4.2 M M M M M
30000 -28.1 -18.6 245 54 28 5.6 3.1 40.6 105.1 8.7 M M
29000 -26.4 -15.5 245 53 27 5.6 3.1 39.1 102.4 7.6 M M
28000 -24.6 -12.3 250 51 26 8.5 4.7 37.9 100.1 6.7 M M
27000 -22.0 -7.6 250 47 24 8.5 4.7 37.3 99.1 6.3 M M
26000 -19.5 -3.1 250 44 23 8.5 4.7 36.8 98.3 6.0 M M
25000 -16.9 1.6 250 40 21 8.2 4.5 36.5 97.6 5.8 M M
24000 -14.7 5.5 255 38 20 7.5 4.1 35.6 96.1 5.2 M M
23000 -12.4 9.7 260 37 19 7.5 4.1 34.8 94.7 4.5 M M
22000 -10.2 13.6 265 36 18 6.7 3.7 34.2 93.5 4.0 M M
21000 -8.8 16.2 270 34 17 4.5 2.4 32.3 90.2 2.4 M M
20000 -7.2 19.0 280 31 16 4.7 2.6 30.1 86.2 0.4 M M
19500 -6.5 20.3 285 31 16 5.2 2.9 29.3 84.7 -0.3 1110 5.6
19000 -5.6 21.9 285 30 15 6.3 3.4 28.7 83.6 -0.9 1068 5.4
18500 -4.7 23.5 290 29 15 6.2 3.4 28.1 82.5 -1.4 1025 5.2
18000 -3.7 25.3 290 29 15 7.0 3.8 27.5 81.6 -1.9 981 5.0
17500 -2.6 27.3 295 28 14 7.1 3.9 27.1 80.8 -2.3 934 4.7
17000 -1.6 29.1 295 27 14 7.2 3.9 26.7 80.0 -2.7 887 4.5
16500 -0.5 31.1 300 27 14 7.3 4.0 26.2 79.2 -3.1 840 4.3
16000 0.6 33.1 305 27 14 7.3 4.0 25.9 78.5 -3.5 793 4.0
15500 1.7 35.1 305 26 14 7.7 4.2 25.5 77.9 -3.9 745 3.8
15000 2.8 37.0 310 26 14 7.7 4.2 25.1 77.3 -4.2 696 3.5
14500 4.0 39.2 310 27 14 7.8 4.3 24.8 76.7 -4.6 647 3.3
14000 5.1 41.2 310 27 14 7.9 4.3 24.5 76.1 -4.9 598 3.0
13500 6.3 43.3 315 27 14 8.2 4.5 24.2 75.6 -5.2 549 2.8
13000 7.5 45.5 315 27 14 8.5 4.6 24.0 75.3 -5.5 497 2.5
12500 8.7 47.7 315 27 14 8.3 4.5 23.8 74.8 -5.8 446 2.3
12000 10.0 50.0 315 27 14 9.3 5.1 23.6 74.6 -6.0 392 2.0
11750 10.7 51.3 315 27 14 8.5 4.6 23.6 74.5 -6.0 365 1.9
11500 11.2 52.2 315 27 14 7.1 3.9 23.4 74.2 -6.2 341 1.7
11250 11.8 53.2 310 27 14 8.4 4.6 23.2 73.8 -6.4 318 1.6
11000 12.5 54.5 310 26 13 9.4 5.2 23.2 73.8 -6.5 290 1.5
10750 13.1 55.6 310 26 13 9.8 5.4 23.2 73.7 -6.6 262 1.3
10500 13.8 56.8 310 26 13 7.4 4.1 23.2 73.7 -6.6 234 1.2
10250 14.3 57.7 305 24 12 6.9 3.8 22.9 73.2 -6.9 214 1.1
10000 14.9 58.8 305 23 12 8.9 4.9 22.8 73.0 -7.1 188 1.0
9750 15.5 59.9 305 22 12 8.6 4.7 22.7 72.8 -7.2 162 0.8
9500 16.1 61.0 300 22 11 7.9 4.4 22.6 72.7 -7.3 136 0.7
9250 16.6 61.9 300 22 11 4.8 2.6 22.3 72.2 -7.6 115 0.6
9000 16.8 62.2 300 23 12 3.3 1.8 21.9 71.4 -8.2 102 0.5
8750 17.0 62.6 295 24 12 4.5 2.5 21.4 70.6 -8.7 89 0.5
8500 17.1 62.8 290 25 13 2.3 1.3 21.0 69.8 -9.3 76 0.4
8250 17.0 62.6 290 25 13 -3.4 -1.9 20.2 68.4 -10.2 73 0.4
8000 16.4 61.5 285 23 12 -10.1 -5.5 19.0 66.2 -11.5 83 0.4
7750 15.3 59.5 285 16 8 -15.2 -8.3 17.3 63.1 -13.4 109 0.6
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 * * * * * *
06/22/2024 at 0900 MDT | 06/22/2024 at 1200 MDT
|
CAPE... 0.0 LI... +1.4 | CAPE... +14.8 LI... -0.1
CINH... 0.0 K Index... +4.2 | CINH... -2.9 K Index... +11.0
|
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 -62.6 -80.7 245 47 24 4.1 2.3 | -63.0 -81.4 245 54 28 3.8 2.1
45000 -55.9 -68.6 250 68 35 4.5 2.5 | -56.3 -69.3 250 77 40 5.0 2.7
40000 -48.5 -55.3 255 86 44 6.9 3.8 | -48.3 -54.9 255 90 46 7.3 4.0
38000 -44.4 -47.9 250 82 42 6.9 3.8 | -43.9 -47.0 250 89 46 7.3 4.0
36000 -40.3 -40.5 245 79 40 6.8 3.7 | -39.5 -39.1 250 89 46 7.0 3.9
34000 -36.5 -33.7 245 72 37 6.4 3.5 | -35.7 -32.3 245 76 39 5.6 3.1
32000 -32.2 -26.0 240 65 33 7.0 3.8 | -32.3 -26.1 240 64 33 6.0 3.3
30000 -28.4 -19.1 245 58 30 6.3 3.5 | -28.2 -18.8 245 59 30 7.0 3.8
29000 -26.5 -15.7 250 55 28 6.3 3.5 | -26.1 -15.0 245 57 29 7.0 3.8
28000 -24.5 -12.1 250 52 27 7.8 4.3 | -24.0 -11.2 250 54 28 6.4 3.5
27000 -22.2 -8.0 250 48 24 7.8 4.3 | -22.1 -7.8 250 50 26 6.4 3.5
26000 -19.9 -3.8 250 43 22 7.8 4.3 | -20.2 -4.4 255 46 24 6.4 3.5
25000 -17.5 0.5 250 39 20 7.7 4.2 | -18.3 -0.9 255 42 22 6.6 3.6
24000 -15.3 4.5 255 37 19 7.6 4.2 | -16.2 2.8 260 40 20 7.2 3.9
23000 -13.0 8.6 255 36 18 7.6 4.2 | -14.0 6.8 260 37 19 7.2 3.9
22000 -10.7 12.7 260 34 18 6.5 3.6 | -11.9 10.6 260 35 18 6.2 3.4
21000 -9.4 15.1 265 31 16 4.4 2.4 | -10.5 13.1 270 32 16 4.5 2.5
20000 -8.1 17.4 275 29 15 4.5 2.5 | -8.9 16.0 275 29 15 4.6 2.5
19500 -7.1 19.2 280 28 14 5.2 2.8 | -8.2 17.2 280 28 14 5.0 2.8
19000 -6.2 20.8 280 27 14 6.0 3.3 | -7.4 18.7 285 27 14 5.6 3.1
18500 -5.4 22.3 285 25 13 5.8 3.2 | -6.6 20.1 285 27 14 5.4 3.0
18000 -4.4 24.1 285 25 13 7.8 4.3 | -5.6 21.9 290 27 14 8.0 4.4
17500 -3.2 26.2 290 25 13 7.9 4.3 | -4.5 23.9 295 26 13 8.0 4.4
17000 -2.1 28.2 295 25 13 7.7 4.2 | -3.3 26.1 295 26 13 8.2 4.5
16500 -1.0 30.2 295 26 13 7.4 4.1 | -2.1 28.2 300 25 13 8.5 4.7
16000 0.1 32.2 300 27 14 7.4 4.0 | -0.9 30.4 300 24 13 8.5 4.7
15500 1.2 34.2 300 27 14 7.8 4.3 | 0.4 32.7 300 24 12 9.3 5.1
15000 2.4 36.3 305 28 14 7.8 4.3 | 1.7 35.1 300 23 12 9.3 5.1
14500 3.5 38.3 305 29 15 8.2 4.5 | 3.1 37.6 305 22 11 8.9 4.9
14000 4.8 40.6 310 29 15 8.3 4.6 | 4.3 39.7 305 20 10 9.0 4.9
13500 6.0 42.8 310 28 15 8.0 4.4 | 5.6 42.1 305 18 9 9.1 5.0
13000 7.1 44.8 315 27 14 8.0 4.4 | 6.9 44.4 310 14 7 9.5 5.2
12500 8.3 46.9 315 26 14 8.7 4.8 | 8.4 47.1 310 13 6 10.4 5.7
12000 9.5 49.1 315 24 13 8.0 4.4 | 9.9 49.8 320 11 6 10.5 5.8
11750 10.1 50.2 315 23 12 7.5 4.1 | 10.7 51.3 320 10 5 9.5 5.2
11500 10.6 51.1 315 22 12 7.1 3.9 | 11.3 52.3 325 10 5 8.9 4.9
11250 11.2 52.2 315 22 11 8.0 4.4 | 12.1 53.8 325 10 5 10.2 5.6
11000 11.8 53.2 315 20 11 8.3 4.5 | 12.8 55.0 325 10 5 10.3 5.7
10750 12.4 54.3 315 19 10 8.6 4.7 | 13.6 56.5 330 10 5 10.6 5.8
10500 13.0 55.4 320 18 9 7.1 3.9 | 14.4 57.9 330 10 5 9.3 5.1
10250 13.5 56.3 320 17 9 7.0 3.9 | 15.0 59.0 330 9 5 9.0 4.9
10000 14.1 57.4 320 17 9 8.5 4.7 | 15.7 60.3 335 9 5 10.0 5.5
9750 14.7 58.5 320 17 9 8.3 4.6 | 16.5 61.7 335 9 5 10.1 5.5
9500 15.3 59.5 320 17 9 7.7 4.2 | 17.2 63.0 335 9 5 8.8 4.8
9250 15.8 60.4 320 16 8 8.2 4.5 | 17.8 64.0 335 9 5 9.4 5.2
9000 16.4 61.5 315 15 8 9.8 5.4 | 18.6 65.5 340 9 5 11.5 6.3
8750 17.1 62.8 315 14 7 10.0 5.5 | 19.5 67.1 340 9 5 11.5 6.3
8500 17.7 63.9 315 13 7 9.7 5.3 | 20.3 68.5 340 9 5 10.3 5.6
8250 18.4 65.1 315 12 6 9.8 5.4 | 21.0 69.8 340 9 5 10.0 5.5
8000 19.2 66.6 315 11 6 14.6 8.0 | 22.0 71.6 345 9 5 18.5 10.2
7750 20.5 68.9 315 9 5 21.1 11.6 | 23.8 74.8 345 9 5 29.1 16.0
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
06/22/2024 at 1500 MDT | 06/22/2024 at 1800 MDT
|
CAPE... +84.2 LI... -1.5 | CAPE... +72.0 LI... -1.0
CINH... -4.5 K Index... +27.4 | CINH... -26.5 K Index... +28.1
|
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 -64.0 -83.2 245 56 29 3.3 1.8 | -63.3 -81.9 255 54 28 3.0 1.6
45000 -57.3 -71.1 250 76 39 5.9 3.2 | -57.3 -71.1 255 73 37 5.3 2.9
40000 -47.9 -54.2 255 86 44 8.0 4.4 | -48.6 -55.5 255 82 42 8.1 4.5
38000 -43.2 -45.8 250 85 44 8.0 4.4 | -43.7 -46.7 250 81 42 8.1 4.4
36000 -38.4 -37.1 245 85 44 7.2 3.9 | -38.9 -38.0 250 79 41 7.5 4.1
34000 -34.8 -30.6 250 75 39 5.2 2.8 | -34.8 -30.6 255 71 36 6.0 3.3
32000 -31.7 -25.1 255 66 34 5.8 3.2 | -31.2 -24.2 265 64 33 6.4 3.5
30000 -27.6 -17.7 250 62 32 7.0 3.8 | -27.3 -17.1 265 58 30 6.5 3.6
29000 -25.5 -13.9 250 60 31 7.0 3.9 | -25.3 -13.5 265 54 28 6.5 3.6
28000 -23.4 -10.1 250 58 30 5.9 3.2 | -23.4 -10.1 265 51 26 6.0 3.3
27000 -21.7 -7.1 255 55 28 5.9 3.3 | -21.7 -7.1 265 51 26 6.0 3.3
26000 -19.9 -3.8 255 52 27 6.0 3.3 | -19.9 -3.8 270 50 26 6.0 3.3
25000 -18.1 -0.6 260 50 26 5.8 3.2 | -18.1 -0.6 270 49 25 5.8 3.2
24000 -16.5 2.3 260 46 24 5.4 3.0 | -16.6 2.1 270 44 23 5.3 2.9
23000 -14.9 5.2 265 43 22 5.5 3.0 | -15.0 5.0 275 38 20 5.4 3.0
22000 -13.3 8.1 265 39 20 5.8 3.2 | -13.5 7.7 275 33 17 6.2 3.4
21000 -11.5 11.3 265 33 17 6.4 3.5 | -10.9 12.4 275 24 13 7.4 4.1
20000 -9.3 15.3 265 26 13 6.7 3.7 | -8.8 16.2 275 18 9 7.5 4.1
19500 -8.4 16.9 265 23 12 7.2 4.0 | -7.8 18.0 270 14 7 8.0 4.4
19000 -7.3 18.9 265 21 11 7.6 4.2 | -6.6 20.1 275 11 6 8.5 4.7
18500 -6.2 20.8 265 19 10 7.7 4.2 | -5.3 22.5 280 8 4 8.8 4.9
18000 -5.2 22.6 265 17 9 7.2 4.0 | -4.3 24.3 280 5 3 6.1 3.3
17500 -4.1 24.6 265 15 8 7.3 4.0 | -3.4 25.9 275 3 2 6.2 3.4
17000 -3.0 26.6 265 13 7 8.3 4.5 | -2.5 27.5 250 1 1 7.0 3.8
16500 -1.7 28.9 260 11 6 9.1 5.0 | -1.3 29.7 000 0 0 7.8 4.3
16000 -0.3 31.5 260 9 5 9.2 5.1 | -0.2 31.6 105 1 1 7.8 4.3
15500 1.1 34.0 260 7 4 9.5 5.2 | 1.1 34.0 105 2 1 8.7 4.8
15000 2.5 36.5 260 5 2 9.5 5.2 | 2.3 36.1 105 3 1 8.7 4.8
14500 3.9 39.0 265 3 1 9.3 5.1 | 3.6 38.5 110 3 2 8.6 4.7
14000 5.3 41.5 285 1 1 9.3 5.1 | 4.9 40.8 115 3 2 8.6 4.7
13500 6.7 44.1 355 1 0 9.8 5.4 | 6.2 43.2 115 4 2 8.9 4.9
13000 8.2 46.8 020 1 1 9.9 5.4 | 7.6 45.7 120 4 2 9.2 5.1
12500 9.6 49.3 030 2 1 10.0 5.5 | 9.0 48.2 120 4 2 9.5 5.2
12000 11.2 52.2 040 2 1 10.9 6.0 | 10.4 50.7 130 4 2 9.4 5.2
11750 11.9 53.4 045 2 1 9.5 5.2 | 11.1 52.0 135 4 2 8.9 4.9
11500 12.6 54.7 045 3 1 8.4 4.6 | 11.7 53.1 135 4 2 8.6 4.7
11250 13.3 55.9 050 3 1 9.8 5.4 | 12.4 54.3 140 5 2 9.2 5.1
11000 14.0 57.2 050 3 1 10.0 5.5 | 13.1 55.6 145 5 2 9.4 5.1
10750 14.7 58.5 050 3 2 10.4 5.7 | 13.8 56.8 150 5 2 9.5 5.2
10500 15.5 59.9 050 3 2 8.5 4.7 | 14.5 58.1 155 5 2 8.9 4.9
10250 16.1 61.0 055 3 2 8.5 4.6 | 15.1 59.2 150 5 3 9.1 5.0
10000 16.8 62.2 055 3 2 10.2 5.6 | 15.8 60.4 155 5 3 9.7 5.3
9750 17.5 63.5 055 4 2 9.9 5.4 | 16.5 61.7 160 5 3 9.8 5.4
9500 18.3 64.9 055 4 2 9.2 5.1 | 17.3 63.1 160 5 3 8.7 4.8
9250 18.9 66.0 060 4 2 9.6 5.3 | 17.8 64.0 165 5 3 8.9 4.9
9000 19.7 67.5 060 4 2 10.8 5.9 | 18.6 65.5 165 5 3 10.3 5.7
8750 20.5 68.9 060 4 2 10.7 5.9 | 19.4 66.9 170 5 3 10.3 5.6
8500 21.3 70.3 060 4 2 10.2 5.6 | 20.1 68.2 170 6 3 10.0 5.5
8250 22.0 71.6 060 4 2 10.0 5.5 | 20.9 69.6 170 6 3 10.0 5.5
8000 22.9 73.2 060 4 2 13.5 7.4 | 21.7 71.1 170 6 3 12.3 6.8
7750 24.0 75.2 060 4 2 18.0 9.9 | 22.7 72.9 170 5 3 15.3 8.4
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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