Soaring Guidance
Issued by NWS Pueblo, CO
Issued by NWS Pueblo, CO
791
UXUS97 KPUB 261203
SRGPUB
Soaring Forecast
National Weather Service Pueblo, Colorado
0603 MDT Sunday, May 26, 2024
This forecast is for the Air Force Academy for Sunday, May 26, 2024:
If the trigger temperature of 52.3 F/11.3 C is reached...then
Thermal Soaring Index....................... Excellent
Maximum rate of lift........................ 1552 ft/min (7.9 m/s)
Maximum height of thermals.................. 24218 ft MSL (16594 ft AGL)
Forecast maximum temperature................... 72.0 F/22.7 C
Time of trigger temperature.................... 0830 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................. 18605 ft MSL (10981 ft AGL)
Thermal soaring outlook for Monday 05/27....... Excellent
Wave Soaring Index............................. Not available
Remarks...
Sunrise/Sunset.................... 05:37:58 / 20:14:54 MDT
Total possible sunshine........... 14 hr 36 min 56 sec (876 min 56 sec)
Altitude of sun at 12:56:26 MDT... 72.31 degrees
Upper air data from numerical model forecast valid on 05/26/2024 at 0600 MDT
Freezing level.................. 11350 ft MSL (3726 ft AGL)
Convective condensation level... 15538 ft MSL (7914 ft AGL)
Lifted condensation level....... 18378 ft MSL (10755 ft AGL)
Lifted index.................... -4.6
K index......................... +12.3
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 -53.5 -64.3 245 48 25 1.9 1.0 M M M M M
45000 -50.9 -59.6 250 57 29 -0.2 -0.1 M M M M M
40000 -51.3 -60.3 270 57 29 -0.2 -0.1 M M M M M
38000 -50.9 -59.6 275 58 30 1.2 0.7 M M M M M
36000 -50.2 -58.4 280 59 30 1.2 0.7 M M M M M
34000 -48.4 -55.1 280 60 31 6.1 3.3 M M M M M
32000 -44.7 -48.5 285 58 30 6.1 3.3 M M M M M
30000 -40.8 -41.4 290 54 28 7.2 4.0 27.7 81.8 4.2 M M
29000 -38.7 -37.7 290 50 26 7.2 4.0 26.6 80.0 3.5 M M
28000 -36.5 -33.7 295 46 24 7.2 4.0 25.8 78.4 2.8 M M
27000 -34.3 -29.7 295 42 22 7.2 4.0 24.9 76.9 2.2 M M
26000 -32.2 -26.0 290 38 20 7.2 4.0 23.9 75.0 1.3 M M
25000 -30.0 -22.0 285 35 18 7.2 4.0 22.9 73.3 0.6 M M
24000 -27.9 -18.2 285 32 16 7.6 4.1 22.1 71.8 -0.1 1538 7.8
23000 -25.5 -13.9 285 32 16 8.2 4.5 21.5 70.6 -0.7 1436 7.3
22000 -23.0 -9.4 285 31 16 8.2 4.5 20.9 69.7 -1.2 1333 6.8
21000 -20.0 -4.0 285 30 16 8.1 4.4 20.3 68.5 -1.7 1205 6.1
20000 -17.6 0.3 285 29 15 8.1 4.4 19.7 67.4 -2.3 1104 5.6
19500 -16.4 2.5 285 28 14 8.1 4.5 19.4 66.9 -2.6 1053 5.4
19000 -15.2 4.6 285 27 14 8.2 4.5 19.2 66.5 -2.8 1003 5.1
18500 -14.0 6.8 290 26 14 7.7 4.2 18.9 66.0 -3.1 953 4.8
18000 -12.9 8.8 290 26 13 7.7 4.2 18.5 65.4 -3.5 904 4.6
17500 -11.8 10.8 290 25 13 7.1 3.9 18.2 64.8 -3.8 855 4.3
17000 -10.8 12.6 295 24 13 6.0 3.3 17.6 63.7 -4.4 814 4.1
16500 -10.0 14.0 300 24 12 6.1 3.3 17.0 62.6 -5.0 773 3.9
16000 -9.1 15.6 305 23 12 5.4 2.9 16.3 61.4 -5.7 733 3.7
15500 -8.4 16.9 310 23 12 5.5 3.0 15.6 60.1 -6.4 695 3.5
15000 -7.6 18.3 315 23 12 5.4 3.0 14.9 58.9 -7.1 657 3.3
14500 -6.8 19.8 320 24 12 5.4 3.0 14.2 57.6 -7.8 619 3.1
14000 -6.0 21.2 325 25 13 5.8 3.2 13.5 56.4 -8.5 581 3.0
13500 -5.1 22.8 330 26 14 6.5 3.6 13.0 55.3 -9.2 539 2.7
13000 -4.2 24.4 330 28 14 9.6 5.3 12.4 54.4 -9.7 497 2.5
12500 -2.8 27.0 330 28 15 6.1 3.3 12.4 54.2 -9.9 441 2.2
12000 -1.8 28.8 330 30 15 7.3 4.0 11.9 53.4 -10.4 396 2.0
11750 -1.2 29.8 330 31 16 9.8 5.4 11.8 53.2 -10.5 370 1.9
11500 -0.5 31.1 330 32 17 9.0 5.0 11.8 53.3 -10.5 340 1.7
11250 0.1 32.2 330 34 17 7.3 4.0 11.6 53.0 -10.7 316 1.6
11000 0.7 33.3 325 35 18 7.8 4.3 11.5 52.7 -10.9 291 1.5
10750 1.2 34.2 325 37 19 7.9 4.3 11.3 52.4 -11.1 267 1.4
10500 1.8 35.2 325 38 20 7.9 4.3 11.2 52.2 -11.3 242 1.2
10250 2.4 36.3 320 40 20 7.4 4.1 11.0 51.9 -11.5 218 1.1
10000 2.9 37.2 320 40 21 6.4 3.5 10.8 51.5 -11.7 195 1.0
9750 3.3 37.9 315 40 21 5.1 2.8 10.5 50.9 -12.1 176 0.9
9500 3.6 38.5 315 39 20 4.5 2.5 10.1 50.2 -12.5 158 0.8
9250 3.9 39.0 310 39 20 5.3 2.9 9.7 49.5 -12.9 141 0.7
9000 4.3 39.7 305 37 19 5.7 3.1 9.4 49.0 -13.3 122 0.6
8750 4.7 40.5 305 35 18 5.4 3.0 9.1 48.4 -13.7 103 0.5
8500 5.1 41.2 305 33 17 4.8 2.6 8.8 47.8 -14.0 84 0.4
8250 5.5 41.9 300 30 15 6.8 3.7 8.4 47.2 -14.4 65 0.3
8000 6.0 42.8 300 27 14 3.9 2.1 8.2 46.8 -14.7 43 0.2
7750 5.9 42.6 300 19 10 -6.7 -3.7 7.4 45.2 -15.6 39 0.2
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 * * * * * *
05/26/2024 at 0900 MDT | 05/26/2024 at 1200 MDT
|
CAPE... 0.0 LI... +3.2 | CAPE... +29.5 LI... +0.9
CINH... 0.0 K Index... +1.0 | CINH... -6.4 K Index... +3.7
|
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 -54.3 -65.7 255 47 24 1.6 0.9 | -54.8 -66.6 255 47 24 2.1 1.2
45000 -52.0 -61.6 260 57 29 -0.1 -0.1 | -51.9 -61.4 265 56 29 -0.1 -0.0
40000 -52.2 -62.0 270 66 34 -0.1 -0.1 | -52.0 -61.6 275 65 33 -0.1 -0.0
38000 -51.4 -60.5 270 67 35 2.2 1.2 | -51.2 -60.2 280 63 33 2.1 1.2
36000 -50.0 -58.0 265 67 35 2.2 1.2 | -49.9 -57.8 285 60 31 2.1 1.2
34000 -48.0 -54.4 265 64 33 4.8 2.6 | -47.6 -53.7 290 57 29 5.6 3.1
32000 -45.1 -49.2 270 56 29 4.8 2.6 | -44.3 -47.7 290 55 28 5.6 3.1
30000 -41.7 -43.1 275 49 25 7.4 4.1 | -40.7 -41.3 285 52 27 6.4 3.5
29000 -39.5 -39.1 275 46 23 7.4 4.1 | -38.8 -37.8 285 50 25 6.4 3.5
28000 -37.3 -35.1 275 42 22 7.4 4.1 | -36.9 -34.4 285 47 24 6.4 3.5
27000 -35.0 -31.0 275 39 20 8.6 4.7 | -34.9 -30.8 280 45 23 7.9 4.4
26000 -32.4 -26.3 280 38 20 8.7 4.8 | -32.6 -26.7 285 43 22 7.9 4.4
25000 -29.8 -21.6 290 38 20 8.7 4.8 | -30.2 -22.4 285 41 21 7.9 4.4
24000 -27.2 -17.0 295 38 20 8.5 4.7 | -27.8 -18.0 285 39 20 8.1 4.4
23000 -24.7 -12.5 295 36 19 8.4 4.6 | -25.4 -13.7 290 38 19 8.2 4.5
22000 -22.2 -8.0 300 34 18 8.4 4.6 | -23.0 -9.4 290 36 19 8.2 4.5
21000 -19.2 -2.6 300 32 16 6.9 3.8 | -20.0 -4.0 290 35 18 7.8 4.3
20000 -17.1 1.2 295 29 15 6.9 3.8 | -17.6 0.3 290 33 17 7.8 4.3
19500 -16.1 3.0 295 27 14 7.0 3.8 | -16.5 2.3 290 32 16 7.8 4.3
19000 -15.1 4.8 295 26 13 7.0 3.8 | -15.3 4.5 285 31 16 7.8 4.3
18500 -14.1 6.6 290 24 13 6.5 3.6 | -14.3 6.3 285 29 15 6.2 3.4
18000 -13.1 8.4 290 23 12 6.6 3.6 | -13.3 8.1 280 27 14 6.4 3.5
17500 -12.1 10.2 285 22 11 7.0 3.8 | -12.4 9.7 275 26 13 6.1 3.3
17000 -11.1 12.0 280 21 11 7.3 4.0 | -11.5 11.3 275 25 13 6.0 3.3
16500 -10.0 14.0 280 20 10 7.3 4.0 | -10.6 12.9 275 23 12 6.0 3.3
16000 -9.0 15.8 280 20 10 6.9 3.8 | -9.8 14.4 280 22 11 6.0 3.3
15500 -7.9 17.8 285 19 10 7.1 3.9 | -8.9 16.0 285 21 11 6.1 3.3
15000 -7.0 19.4 290 19 10 5.3 2.9 | -8.0 17.6 295 21 11 6.8 3.7
14500 -6.3 20.7 300 19 10 5.2 2.8 | -7.1 19.2 295 20 11 6.8 3.7
14000 -5.5 22.1 305 18 10 5.3 2.9 | -6.1 21.0 300 20 10 7.7 4.2
13500 -4.7 23.5 315 18 9 5.5 3.0 | -5.0 23.0 300 18 9 7.9 4.3
13000 -4.0 24.8 325 19 10 7.5 4.1 | -3.8 25.2 305 17 8 10.8 5.9
12500 -2.7 27.1 330 19 10 7.3 4.0 | -2.3 27.9 305 14 7 8.0 4.4
12000 -1.6 29.1 335 21 11 8.4 4.6 | -1.1 30.0 310 12 6 9.7 5.3
11750 -0.8 30.6 335 22 11 10.4 5.7 | -0.3 31.5 310 12 6 11.2 6.2
11500 -0.1 31.8 335 23 12 8.8 4.8 | 0.5 32.9 315 12 6 9.8 5.4
11250 0.5 32.9 335 25 13 7.7 4.2 | 1.2 34.2 315 12 6 9.0 4.9
11000 1.1 34.0 330 27 14 6.9 3.8 | 1.9 35.4 315 12 6 9.2 5.1
10750 1.5 34.7 330 28 15 5.2 2.9 | 2.6 36.7 315 12 6 9.1 5.0
10500 1.8 35.2 325 30 15 5.3 2.9 | 3.3 37.9 315 12 6 9.4 5.1
10250 2.2 36.0 325 30 16 4.6 2.5 | 4.0 39.2 320 11 6 11.0 6.1
10000 2.5 36.5 320 30 15 6.3 3.5 | 4.9 40.8 320 11 6 10.9 6.0
9750 3.0 37.4 320 28 14 8.7 4.8 | 5.6 42.1 320 11 6 9.8 5.4
9500 3.6 38.5 320 25 13 8.3 4.5 | 6.4 43.5 320 11 6 10.0 5.5
9250 4.2 39.6 315 23 12 9.2 5.1 | 7.1 44.8 320 11 6 10.2 5.6
9000 5.0 41.0 315 22 11 10.5 5.8 | 7.9 46.2 325 11 6 10.4 5.7
8750 5.7 42.3 315 21 11 10.7 5.8 | 8.6 47.5 325 11 6 10.3 5.7
8500 6.5 43.7 315 21 11 10.5 5.7 | 9.4 48.9 325 11 6 9.9 5.4
8250 7.3 45.1 315 20 10 11.1 6.1 | 10.2 50.4 325 11 6 11.9 6.5
8000 8.3 46.9 315 20 10 16.2 8.9 | 13.2 55.8 330 10 5 29.2 16.0
7750 9.7 49.5 315 17 9 22.6 12.4 | 15.1 59.2 330 10 5 16.1 8.8
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
05/26/2024 at 1500 MDT | 05/26/2024 at 1800 MDT
|
CAPE... +170.0 LI... -1.0 | CAPE... +80.7 LI... -1.0
CINH... 0.0 K Index... +17.0 | CINH... -10.9 K Index... +18.1
|
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 -55.1 -67.2 260 48 24 1.8 1.0 | -55.8 -68.4 265 53 27 1.2 0.6
45000 -53.0 -63.4 270 57 30 -1.4 -0.8 | -54.7 -66.5 275 58 30 -2.3 -1.3
40000 -55.2 -67.4 280 60 31 -1.3 -0.7 | -58.3 -72.9 280 58 30 -2.3 -1.2
38000 -53.8 -64.8 290 58 30 3.7 2.0 | -55.9 -68.6 285 56 29 6.0 3.3
36000 -51.4 -60.5 305 58 30 3.7 2.0 | -51.9 -61.4 290 55 28 6.0 3.3
34000 -48.1 -54.6 305 60 31 7.6 4.2 | -47.7 -53.9 295 55 28 8.0 4.4
32000 -43.5 -46.3 305 62 32 7.6 4.2 | -42.9 -45.2 295 55 28 8.0 4.4
30000 -38.8 -37.8 305 61 32 8.2 4.5 | -38.1 -36.6 295 51 26 8.2 4.5
29000 -36.4 -33.5 310 59 30 8.2 4.5 | -35.6 -32.1 295 47 24 8.2 4.5
28000 -33.9 -29.0 310 57 29 8.2 4.5 | -33.1 -27.6 290 43 22 8.2 4.5
27000 -31.7 -25.1 315 55 28 5.3 2.9 | -30.7 -23.3 295 41 21 7.8 4.3
26000 -30.0 -22.0 310 52 27 5.6 3.1 | -28.4 -19.1 300 41 21 7.8 4.3
25000 -28.4 -19.1 310 50 26 5.6 3.1 | -26.1 -15.0 305 42 21 7.8 4.3
24000 -26.6 -15.9 305 47 24 6.7 3.7 | -23.9 -11.0 310 42 22 5.0 2.7
23000 -24.6 -12.3 305 44 22 6.9 3.8 | -22.4 -8.3 310 40 21 5.1 2.8
22000 -22.0 -7.6 300 39 20 7.0 3.8 | -20.5 -4.9 305 37 19 5.1 2.8
21000 -19.8 -3.6 300 36 18 7.6 4.2 | -18.7 -1.7 305 35 18 6.8 3.7
20000 -17.5 0.5 295 32 17 7.7 4.2 | -16.6 2.1 295 32 16 6.8 3.7
19500 -16.4 2.5 295 30 16 7.6 4.2 | -15.6 3.9 290 31 16 6.8 3.7
19000 -15.2 4.6 295 29 15 7.3 4.0 | -14.6 5.7 285 30 15 6.9 3.8
18500 -14.3 6.3 290 27 14 6.1 3.4 | -13.6 7.5 280 29 15 7.0 3.8
18000 -13.4 7.9 285 27 14 6.2 3.4 | -12.6 9.3 280 29 15 7.0 3.8
17500 -12.5 9.5 285 26 13 7.6 4.1 | -11.5 11.3 275 28 14 8.5 4.7
17000 -11.4 11.5 285 24 13 7.8 4.3 | -10.3 13.5 270 25 13 8.6 4.7
16500 -10.3 13.5 285 23 12 8.2 4.5 | -9.1 15.6 270 22 12 8.8 4.8
16000 -9.1 15.6 280 20 10 8.6 4.7 | -7.8 18.0 270 20 10 8.9 4.9
15500 -7.9 17.8 275 16 8 8.6 4.7 | -6.6 20.1 270 17 9 8.9 4.9
15000 -6.6 20.1 275 14 7 8.9 4.9 | -5.3 22.5 270 15 8 8.7 4.8
14500 -5.3 22.5 275 12 6 8.8 4.8 | -4.0 24.8 270 14 7 8.7 4.8
14000 -3.9 25.0 275 10 5 9.9 5.4 | -2.6 27.3 270 12 6 9.1 5.0
13500 -2.4 27.7 280 9 5 9.8 5.4 | -1.3 29.7 275 10 5 9.0 4.9
13000 -0.8 30.6 280 8 4 11.9 6.5 | 0.1 32.2 275 8 4 10.5 5.8
12500 0.7 33.3 285 8 4 8.1 4.5 | 1.5 34.7 280 6 3 7.5 4.1
12000 2.0 35.6 285 7 4 9.5 5.2 | 2.7 36.9 290 4 2 8.8 4.8
11750 2.7 36.9 285 7 4 10.1 5.5 | 3.4 38.1 295 4 2 9.2 5.1
11500 3.4 38.1 290 7 4 10.0 5.5 | 4.1 39.4 300 4 2 10.2 5.6
11250 4.2 39.6 290 7 4 10.0 5.5 | 4.9 40.8 310 3 2 10.6 5.8
11000 4.9 40.8 290 7 3 9.3 5.1 | 5.6 42.1 320 3 2 9.3 5.1
10750 5.6 42.1 295 7 3 8.6 4.7 | 6.2 43.2 325 3 1 8.5 4.7
10500 6.2 43.2 295 6 3 9.3 5.1 | 6.9 44.4 335 3 1 9.4 5.2
10250 7.0 44.6 295 6 3 11.1 6.1 | 7.7 45.9 345 3 1 11.3 6.2
10000 7.8 46.0 295 6 3 10.7 5.8 | 8.5 47.3 350 3 1 10.4 5.7
9750 8.6 47.5 300 6 3 9.7 5.3 | 9.2 48.6 355 3 1 9.3 5.1
9500 9.3 48.7 300 6 3 9.7 5.3 | 9.9 49.8 360 3 1 9.5 5.2
9250 10.1 50.2 300 6 3 10.7 5.8 | 10.7 51.3 005 3 1 10.0 5.5
9000 10.9 51.6 305 6 3 10.7 5.9 | 11.4 52.5 010 3 1 10.2 5.6
8750 11.6 52.9 305 5 3 9.9 5.4 | 12.2 54.0 010 3 1 9.7 5.3
8500 12.4 54.3 310 5 3 9.8 5.3 | 12.9 55.2 015 3 2 9.5 5.2
8250 13.1 55.6 310 5 3 11.2 6.1 | 13.6 56.5 020 3 2 10.8 5.9
8000 14.2 57.6 310 5 3 18.9 10.3 | 14.5 58.1 020 3 2 14.2 7.8
7750 15.9 60.6 315 5 2 26.8 14.7 | 15.7 60.3 020 3 2 15.7 8.6
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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