Soaring Guidance
Issued by NWS Pueblo, CO
Issued by NWS Pueblo, CO
844
UXUS97 KPUB 051205
SRGPUB
Soaring Forecast
National Weather Service Pueblo, Colorado
0605 MDT Saturday, October 5, 2024
This forecast is for the Air Force Academy for Saturday, October 5, 2024:
If the trigger temperature of 71.5 F/22.0 C is reached...then
Thermal Soaring Index....................... Excellent
Maximum rate of lift........................ 1658 ft/min (8.4 m/s)
Maximum height of thermals.................. 24254 ft MSL (16651 ft AGL)
Forecast maximum temperature................... 85.0 F/29.9 C
Time of trigger temperature.................... 0945 MDT
Time of overdevelopment........................ None
Middle/high clouds during soaring window....... None
Surface winds during soaring window............ 20 mph or less
Height of the -3 thermal index................. 20849 ft MSL (13246 ft AGL)
Thermal soaring outlook for Sunday 10/06....... Good
Wave Soaring Index............................. Not available
Remarks...
Sunrise/Sunset.................... 06:59:52 / 18:35:04 MDT
Total possible sunshine........... 11 hr 35 min 12 sec (695 min 12 sec)
Altitude of sun at 12:47:28 MDT... 45.78 degrees
Upper air data from numerical model forecast valid on 10/05/2024 at 0600 MDT
Freezing level.................. 15020 ft MSL (7417 ft AGL)
Convective condensation level... 22818 ft MSL (15215 ft AGL)
Lifted condensation level....... 23684 ft MSL (16081 ft AGL)
Lifted index.................... -0.3
K index......................... +2.2
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 -64.3 -83.7 280 43 22 3.4 1.8 M M M M M
45000 -58.2 -72.8 280 52 27 5.3 2.9 M M M M M
40000 -50.4 -58.7 280 47 24 4.0 2.2 M M M M M
38000 -48.0 -54.4 280 45 23 4.1 2.2 M M M M M
36000 -45.5 -49.9 280 42 22 4.2 2.3 M M M M M
34000 -41.9 -43.4 275 39 20 6.7 3.7 M M M M M
32000 -37.4 -35.3 270 36 18 6.7 3.7 M M M M M
30000 -33.1 -27.6 265 33 17 7.4 4.1 35.3 95.5 4.6 M M
29000 -30.8 -23.4 260 31 16 7.4 4.1 34.4 94.0 3.9 M M
28000 -28.6 -19.5 260 30 15 7.2 3.9 33.7 92.7 3.4 M M
27000 -26.6 -15.9 255 28 15 6.7 3.7 32.5 90.4 2.4 M M
26000 -24.6 -12.3 255 27 14 6.7 3.7 31.3 88.4 1.5 M M
25000 -22.6 -8.7 250 26 13 6.7 3.7 30.3 86.6 0.7 M M
24000 -20.6 -5.1 250 25 13 6.7 3.7 29.2 84.6 -0.2 1639 8.3
23000 -18.6 -1.5 245 23 12 6.7 3.7 28.1 82.6 -1.2 1550 7.9
22000 -16.6 2.1 245 22 11 6.7 3.7 27.1 80.8 -2.0 1460 7.4
21000 -14.4 6.1 245 20 11 7.6 4.2 26.2 79.2 -2.8 1365 6.9
20000 -12.1 10.2 250 19 10 7.6 4.2 25.5 77.9 -3.5 1268 6.4
19500 -10.4 13.3 250 19 10 7.4 4.1 25.0 77.0 -4.0 1195 6.1
19000 -9.4 15.1 255 18 9 6.3 3.5 24.5 76.1 -4.5 1151 5.8
18500 -8.5 16.7 260 18 9 6.4 3.5 23.9 75.1 -5.0 1108 5.6
18000 -7.5 18.5 270 18 9 7.8 4.3 23.4 74.2 -5.5 1063 5.4
17500 -6.3 20.7 275 19 10 8.4 4.6 23.2 73.8 -5.8 1012 5.1
17000 -5.1 22.8 280 19 10 8.4 4.6 23.0 73.4 -6.1 961 4.9
16500 -3.8 25.2 285 20 10 8.5 4.7 22.8 73.0 -6.3 909 4.6
16000 -2.6 27.3 285 20 10 8.4 4.6 22.6 72.6 -6.6 857 4.4
15500 -1.3 29.7 290 21 11 9.8 5.4 22.4 72.4 -6.8 803 4.1
15000 0.2 32.4 290 21 11 9.8 5.4 22.4 72.4 -6.8 745 3.8
14500 1.6 34.9 290 21 11 9.6 5.3 22.4 72.4 -6.9 687 3.5
14000 3.0 37.4 290 23 12 9.6 5.3 22.4 72.3 -7.0 630 3.2
13500 4.4 39.9 285 24 12 9.4 5.1 22.4 72.3 -7.0 573 2.9
13000 5.8 42.4 285 24 12 9.2 5.1 22.3 72.1 -7.1 517 2.6
12500 7.3 45.1 285 22 12 10.1 5.5 22.3 72.1 -7.2 458 2.3
12000 8.8 47.8 290 21 11 10.0 5.5 22.3 72.2 -7.1 398 2.0
11750 9.5 49.1 290 20 10 9.7 5.3 22.3 72.2 -7.1 368 1.9
11500 10.2 50.4 290 20 10 8.9 4.9 22.3 72.2 -7.2 340 1.7
11250 10.9 51.6 290 20 10 9.1 5.0 22.2 72.0 -7.3 313 1.6
11000 11.6 52.9 290 20 10 9.5 5.2 22.2 72.0 -7.3 284 1.4
10750 12.3 54.1 290 21 11 9.7 5.3 22.2 71.9 -7.4 256 1.3
10500 13.0 55.4 290 21 11 8.7 4.7 22.2 71.9 -7.4 227 1.2
10250 13.6 56.5 290 20 10 7.9 4.3 22.0 71.7 -7.6 203 1.0
10000 14.2 57.6 290 21 11 8.2 4.5 21.9 71.4 -7.7 177 0.9
9750 14.8 58.6 285 22 11 8.4 4.6 21.8 71.2 -7.9 151 0.8
9500 15.4 59.7 285 22 11 7.4 4.1 21.7 71.0 -8.0 125 0.6
9250 15.9 60.6 285 22 11 6.0 3.3 21.4 70.6 -8.3 104 0.5
9000 16.3 61.3 285 22 11 6.2 3.4 21.1 70.1 -8.6 83 0.4
8750 16.8 62.2 285 23 12 7.2 3.9 20.9 69.6 -8.9 62 0.3
8500 17.3 63.1 285 24 12 5.0 2.7 20.7 69.2 -9.1 40 0.2
8250 17.4 63.3 285 24 12 -1.5 -0.9 20.1 68.1 -9.7 28 0.1
8000 16.7 62.1 280 23 12 -23.1 -12.7 18.6 65.5 -11.2 43 0.2
7750 13.8 56.8 275 17 9 -50.7 -27.8 15.0 59.0 -14.9 123 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 * * * * * *
10/05/2024 at 0900 MDT | 10/05/2024 at 1200 MDT
|
CAPE... 0.0 LI... +0.8 | CAPE... +0.2 LI... +0.6
CINH... 0.0 K Index... +13.0 | CINH... -1.3 K Index... +11.3
|
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 -63.2 -81.8 290 41 21 4.6 2.5 | -64.1 -83.4 295 29 15 3.2 1.7
45000 -56.5 -69.7 290 52 27 4.2 2.3 | -58.3 -72.9 310 33 17 5.5 3.0
40000 -50.2 -58.4 285 51 26 4.5 2.5 | -50.0 -58.0 315 42 22 5.7 3.1
38000 -47.5 -53.5 280 48 25 4.5 2.5 | -46.6 -51.9 305 41 21 5.7 3.1
36000 -44.5 -48.1 275 46 24 4.4 2.4 | -42.8 -45.0 295 40 21 5.8 3.2
34000 -41.1 -42.0 270 40 21 5.9 3.2 | -40.1 -40.2 295 37 19 4.2 2.3
32000 -37.6 -35.7 265 34 17 5.9 3.3 | -37.5 -35.5 290 34 17 4.3 2.3
30000 -33.4 -28.1 265 29 15 7.4 4.1 | -33.6 -28.5 300 30 15 7.3 4.0
29000 -31.2 -24.2 265 27 14 7.4 4.1 | -31.4 -24.5 305 28 14 7.3 4.0
28000 -29.0 -20.2 265 24 13 7.1 3.9 | -29.3 -20.7 310 27 14 7.4 4.1
27000 -27.1 -16.8 260 23 12 6.2 3.4 | -26.9 -16.4 315 24 13 7.8 4.3
26000 -25.3 -13.5 250 22 11 6.2 3.4 | -24.6 -12.3 315 22 11 7.8 4.3
25000 -23.4 -10.1 245 21 11 6.2 3.4 | -22.3 -8.1 315 20 10 8.0 4.4
24000 -21.6 -6.9 240 18 9 6.1 3.4 | -20.4 -4.7 310 16 8 5.4 3.0
23000 -19.7 -3.5 240 15 8 6.1 3.4 | -18.8 -1.8 295 13 7 5.4 3.0
22000 -17.9 -0.2 245 11 6 6.0 3.3 | -17.2 1.0 275 10 5 5.4 2.9
21000 -15.3 4.5 265 11 6 7.2 4.0 | -14.9 5.2 265 8 4 6.4 3.5
20000 -13.2 8.2 280 13 7 7.3 4.0 | -13.0 8.6 260 6 3 6.4 3.5
19500 -12.1 10.2 285 14 7 7.3 4.0 | -12.1 10.2 255 5 3 6.6 3.6
19000 -11.1 12.0 285 18 9 7.2 3.9 | -11.0 12.2 275 5 3 8.2 4.5
18500 -10.1 13.8 290 23 12 7.2 4.0 | -9.8 14.4 305 7 4 8.1 4.4
18000 -9.0 15.8 290 27 14 8.9 4.9 | -8.6 16.5 320 9 5 7.9 4.4
17500 -7.6 18.3 290 27 14 9.4 5.2 | -7.5 18.5 315 12 6 8.0 4.4
17000 -6.2 20.8 295 27 14 9.5 5.2 | -6.3 20.7 310 15 8 8.2 4.5
16500 -4.8 23.4 290 26 13 9.5 5.2 | -5.1 22.8 310 16 8 8.9 4.9
16000 -3.3 26.1 290 26 13 9.5 5.2 | -3.8 25.2 305 17 9 8.8 4.8
15500 -1.9 28.6 290 24 12 9.7 5.3 | -2.4 27.7 305 17 9 9.7 5.3
15000 -0.4 31.3 290 21 11 9.7 5.3 | -1.0 30.2 305 16 8 9.7 5.3
14500 1.0 33.8 290 19 10 9.5 5.2 | 0.5 32.9 300 16 8 9.7 5.3
14000 2.4 36.3 295 19 10 9.4 5.1 | 1.9 35.4 300 15 8 9.7 5.3
13500 3.8 38.8 295 18 10 9.5 5.2 | 3.3 37.9 300 14 7 9.7 5.3
13000 5.2 41.4 300 19 10 9.7 5.3 | 4.8 40.6 300 14 7 9.7 5.3
12500 6.6 43.9 300 19 10 9.4 5.1 | 6.2 43.2 300 14 7 9.9 5.4
12000 8.2 46.8 305 17 9 10.7 5.9 | 7.8 46.0 300 13 7 10.6 5.8
11750 9.0 48.2 305 16 8 10.1 5.6 | 8.5 47.3 300 13 7 9.8 5.4
11500 9.7 49.5 310 15 8 8.6 4.7 | 9.2 48.6 300 13 7 8.6 4.7
11250 10.3 50.5 310 15 8 8.7 4.8 | 9.9 49.8 300 13 7 9.8 5.4
11000 11.0 51.8 310 15 8 9.3 5.1 | 10.7 51.3 300 13 7 10.5 5.8
10750 11.7 53.1 310 15 8 9.2 5.0 | 11.5 52.7 300 13 7 10.8 5.9
10500 12.3 54.1 310 15 8 9.0 4.9 | 12.2 54.0 300 13 6 8.9 4.9
10250 13.0 55.4 315 14 7 8.4 4.6 | 12.8 55.0 305 12 6 8.8 4.8
10000 13.6 56.5 310 14 7 8.2 4.5 | 13.6 56.5 305 12 6 10.5 5.8
9750 14.2 57.6 310 15 8 8.4 4.6 | 14.4 57.9 305 12 6 10.4 5.7
9500 14.8 58.6 310 16 8 7.7 4.2 | 15.1 59.2 305 12 6 9.1 5.0
9250 15.3 59.5 305 17 9 6.6 3.6 | 15.8 60.4 305 12 6 9.0 5.0
9000 15.8 60.4 300 18 9 6.6 3.6 | 16.5 61.7 305 12 6 11.0 6.0
8750 16.3 61.3 300 20 10 7.3 4.0 | 17.3 63.1 305 12 6 11.1 6.1
8500 16.9 62.4 295 22 11 5.3 2.9 | 18.2 64.8 305 12 6 10.6 5.8
8250 17.1 62.8 290 23 12 2.0 1.1 | 18.9 66.0 305 11 6 10.7 5.9
8000 17.2 63.0 290 22 11 1.8 1.0 | 19.9 67.8 305 11 6 17.0 9.3
7750 17.3 63.1 285 16 8 2.4 1.3 | 21.5 70.7 305 10 5 25.4 13.9
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
10/05/2024 at 1500 MDT | 10/05/2024 at 1800 MDT
|
CAPE... +16.9 LI... -0.6 | CAPE... +0.3 LI... +0.1
CINH... -1.1 K Index... +18.4 | CINH... -0.3 K Index... +19.2
|
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 -63.9 -83.0 295 26 13 2.4 1.3 | -64.1 -83.4 300 18 9 2.5 1.4
45000 -58.3 -72.9 310 25 13 6.8 3.8 | -58.5 -73.3 315 17 9 6.1 3.4
40000 -48.3 -54.9 330 37 19 4.3 2.4 | -49.5 -57.1 330 32 16 5.2 2.8
38000 -45.7 -50.3 335 36 18 4.4 2.4 | -46.4 -51.5 345 32 16 5.2 2.8
36000 -42.8 -45.0 335 35 18 4.4 2.4 | -42.9 -45.2 355 33 17 5.1 2.8
34000 -40.1 -40.2 335 34 18 4.5 2.5 | -39.0 -38.2 005 34 17 6.8 3.7
32000 -37.4 -35.3 330 34 18 4.4 2.4 | -34.9 -30.8 010 34 18 6.8 3.7
30000 -33.6 -28.5 325 33 17 6.9 3.8 | -31.5 -24.7 005 33 17 5.4 3.0
29000 -31.5 -24.7 325 32 17 6.9 3.8 | -29.9 -21.8 005 33 17 5.4 3.0
28000 -29.5 -21.1 320 32 16 7.4 4.0 | -28.3 -18.9 360 33 17 6.2 3.4
27000 -27.1 -16.8 325 30 16 8.2 4.5 | -26.1 -15.0 355 31 16 7.3 4.0
26000 -24.6 -12.3 325 28 15 8.2 4.5 | -24.0 -11.2 355 29 15 7.3 4.0
25000 -22.1 -7.8 325 27 14 8.4 4.6 | -21.8 -7.2 355 28 14 7.2 4.0
24000 -20.1 -4.2 325 23 12 6.5 3.6 | -19.6 -3.3 350 25 13 7.5 4.1
23000 -18.1 -0.6 315 19 10 6.5 3.6 | -17.3 0.9 340 22 11 7.5 4.1
22000 -16.2 2.8 300 16 8 6.6 3.6 | -15.1 4.8 330 19 10 7.5 4.1
21000 -14.3 6.3 285 14 7 5.1 2.8 | -13.3 8.1 310 16 8 4.6 2.5
20000 -12.8 9.0 265 13 7 5.2 2.9 | -12.0 10.4 290 15 8 4.7 2.6
19500 -12.1 10.2 255 13 7 5.9 3.2 | -11.3 11.7 285 15 8 5.4 3.0
19000 -10.9 12.4 255 13 6 9.2 5.1 | -10.2 13.6 280 14 7 8.3 4.6
18500 -9.6 14.7 260 12 6 9.0 5.0 | -9.1 15.6 280 13 7 8.3 4.5
18000 -8.3 17.1 260 11 6 8.9 4.9 | -7.9 17.8 280 12 6 8.6 4.7
17500 -7.0 19.4 270 10 5 9.0 4.9 | -6.6 20.1 270 11 6 8.7 4.8
17000 -5.7 21.7 275 10 5 9.0 4.9 | -5.4 22.3 265 11 5 8.9 4.9
16500 -4.4 24.1 280 8 4 9.0 4.9 | -4.0 24.8 260 10 5 9.4 5.2
16000 -3.1 26.4 280 7 3 8.9 4.9 | -2.6 27.3 255 8 4 9.4 5.1
15500 -1.7 28.9 280 6 3 10.1 5.6 | -1.2 29.8 250 8 4 9.4 5.2
15000 -0.2 31.6 285 6 3 10.1 5.5 | 0.2 32.4 250 7 3 9.4 5.2
14500 1.3 34.3 285 6 3 9.8 5.4 | 1.6 34.9 250 6 3 9.2 5.1
14000 2.8 37.0 285 6 3 9.8 5.4 | 3.0 37.4 250 5 3 9.2 5.1
13500 4.2 39.6 290 6 3 9.7 5.3 | 4.3 39.7 255 4 2 9.4 5.2
13000 5.7 42.3 295 5 3 9.6 5.3 | 5.8 42.4 260 3 1 9.7 5.3
12500 7.1 44.8 295 5 3 10.2 5.6 | 7.3 45.1 265 2 1 10.2 5.6
12000 8.7 47.7 300 5 3 11.2 6.2 | 8.8 47.8 285 2 1 10.0 5.5
11750 9.5 49.1 300 5 3 10.0 5.5 | 9.5 49.1 300 1 1 9.3 5.1
11500 10.2 50.4 300 5 3 8.1 4.5 | 10.2 50.4 315 1 1 8.5 4.6
11250 10.8 51.4 305 5 3 9.4 5.2 | 10.8 51.4 330 1 1 9.3 5.1
11000 11.6 52.9 305 5 3 10.4 5.7 | 11.5 52.7 345 1 1 9.9 5.4
10750 12.4 54.3 305 5 3 10.5 5.8 | 12.3 54.1 360 2 1 9.7 5.3
10500 13.1 55.6 305 5 3 9.2 5.1 | 13.0 55.4 005 2 1 9.8 5.4
10250 13.8 56.8 310 5 3 9.0 5.0 | 13.7 56.7 015 2 1 9.5 5.2
10000 14.5 58.1 310 5 3 10.2 5.6 | 14.4 57.9 020 2 1 9.0 5.0
9750 15.3 59.5 310 5 3 10.1 5.6 | 15.1 59.2 025 3 1 9.4 5.2
9500 16.0 60.8 315 5 3 9.2 5.1 | 15.8 60.4 030 3 1 8.2 4.5
9250 16.7 62.1 315 5 3 9.3 5.1 | 16.4 61.5 030 3 2 8.5 4.7
9000 17.4 63.3 315 5 3 10.6 5.8 | 17.1 62.8 030 3 2 10.3 5.7
8750 18.2 64.8 320 5 3 10.7 5.9 | 17.9 64.2 035 4 2 10.5 5.8
8500 19.0 66.2 320 5 3 10.2 5.6 | 18.6 65.5 035 4 2 9.9 5.4
8250 19.8 67.6 320 5 3 10.3 5.7 | 19.3 66.7 035 4 2 8.7 4.8
8000 20.7 69.3 325 5 3 16.2 8.9 | 19.9 67.8 035 4 2 6.4 3.5
7750 22.2 72.0 325 5 3 24.1 13.2 | 20.2 68.4 035 3 2 3.6 2.0
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
________________________________________________________________________________
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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