Soaring Guidance
Issued by NWS Pueblo, CO
Issued by NWS Pueblo, CO
984
UXUS97 KPUB 231212
SRGPUB
Soaring Forecast
National Weather Service Pueblo, Colorado
0512 MST Sunday, February 23, 2025
This forecast is for the Air Force Academy for Sunday, February 23, 2025:
If the trigger temperature of 44.9 F/7.2 C is reached...then
Thermal Soaring Index....................... Excellent
Maximum rate of lift........................ 1166 ft/min (5.9 m/s)
Maximum height of thermals.................. 20167 ft MSL (12557 ft AGL)
Forecast maximum temperature................... 58.0 F/14.9 C
Time of trigger temperature.................... 0945 MST
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................. 15806 ft MSL (8197 ft AGL)
Thermal soaring outlook for Monday 02/24....... Excellent
Wave Soaring Index............................. Not available
Remarks...
Sunrise/Sunset.................... 06:39:22 / 17:45:42 MST
Total possible sunshine........... 11 hr 6 min 20 sec (666 min 20 sec)
Altitude of sun at 12:12:32 MST... 41.41 degrees
Upper air data from numerical model forecast valid on 02/23/2025 at 0500 MST
Freezing level.................. 8025 ft MSL (415 ft AGL)
Additional freezing level....... 9546 ft MSL (1936 ft AGL)
Convective condensation level... 16881 ft MSL (9271 ft AGL)
Lifted condensation level....... 17971 ft MSL (10361 ft AGL)
Lifted index.................... -1.4
K index......................... +7.3
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 -57.5 -71.5 320 38 19 1.3 0.7 M M M M M
45000 -55.6 -68.1 325 37 19 1.4 0.7 M M M M M
40000 -53.4 -64.1 330 46 24 1.5 0.8 M M M M M
38000 -52.7 -62.9 330 47 24 0.6 0.3 M M M M M
36000 -52.4 -62.3 340 46 24 0.6 0.3 M M M M M
34000 -51.7 -61.1 345 45 23 4.3 2.3 M M M M M
32000 -49.4 -56.9 335 41 21 3.9 2.1 M M M M M
30000 -46.8 -52.2 325 39 20 7.1 3.9 21.9 71.4 5.7 M M
29000 -44.7 -48.5 320 37 19 6.9 3.8 20.6 69.2 4.8 M M
28000 -42.7 -44.9 310 36 18 6.9 3.8 19.5 67.2 4.0 M M
27000 -40.6 -41.1 305 35 18 7.0 3.8 18.6 65.5 3.3 M M
26000 -38.4 -37.1 305 35 18 7.7 4.2 17.7 63.8 2.6 M M
25000 -36.1 -33.0 310 35 18 7.7 4.2 16.9 62.4 2.0 M M
24000 -33.8 -28.8 310 36 18 7.6 4.2 16.2 61.2 1.5 M M
23000 -30.5 -22.9 310 33 17 8.9 4.9 15.7 60.2 1.0 M M
22000 -27.8 -18.0 305 30 15 8.9 4.9 15.4 59.7 0.8 M M
21000 -25.3 -13.5 305 28 14 7.7 4.2 15.1 59.1 0.5 M M
20000 -22.9 -9.2 310 26 13 7.8 4.3 14.3 57.8 -0.2 1141 5.8
19500 -21.8 -7.2 310 26 13 7.9 4.3 14.0 57.2 -0.4 1091 5.5
19000 -20.6 -5.1 315 25 13 7.9 4.3 13.7 56.7 -0.7 1042 5.3
18500 -19.4 -2.9 315 24 12 7.4 4.1 13.4 56.1 -1.0 993 5.0
18000 -18.4 -1.1 315 22 11 7.4 4.1 13.0 55.4 -1.4 945 4.8
17500 -17.3 0.9 320 20 10 7.5 4.1 12.6 54.7 -1.8 898 4.6
17000 -16.1 3.0 325 19 10 7.7 4.2 12.3 54.1 -2.1 849 4.3
16500 -15.0 5.0 325 18 9 7.8 4.3 11.9 53.5 -2.4 799 4.1
16000 -13.9 7.0 330 17 9 6.9 3.8 11.5 52.7 -2.8 752 3.8
15500 -12.9 8.8 335 17 9 6.9 3.8 11.1 51.9 -3.3 706 3.6
15000 -11.8 10.8 340 16 8 7.2 3.9 10.6 51.1 -3.7 660 3.4
14500 -10.8 12.6 340 16 8 7.2 4.0 10.2 50.4 -4.2 614 3.1
14000 -9.7 14.5 345 15 8 6.8 3.7 9.8 49.6 -4.6 567 2.9
13500 -8.7 16.3 350 15 8 6.6 3.6 9.3 48.7 -5.1 524 2.7
13000 -7.8 18.0 355 15 8 7.2 4.0 8.8 47.8 -5.6 479 2.4
12500 -6.7 19.9 360 15 8 6.6 3.6 8.4 47.1 -6.0 432 2.2
12000 -5.7 21.7 005 14 7 6.8 3.7 7.9 46.1 -6.6 389 2.0
11750 -5.2 22.6 005 14 7 7.4 4.1 7.7 45.8 -6.8 366 1.9
11500 -4.7 23.5 005 14 7 7.1 3.9 7.5 45.4 -7.0 343 1.7
11250 -4.2 24.4 005 14 7 6.6 3.6 7.2 45.0 -7.3 320 1.6
11000 -3.7 25.3 005 14 7 6.7 3.7 7.0 44.6 -7.5 298 1.5
10750 -3.2 26.2 360 15 8 7.2 4.0 6.8 44.2 -7.8 275 1.4
10500 -2.6 27.3 355 16 8 6.4 3.5 6.6 43.8 -8.0 252 1.3
10250 -2.1 28.2 355 17 9 9.2 5.0 6.3 43.4 -8.2 229 1.2
10000 -1.3 29.7 350 18 9 9.9 5.5 6.4 43.5 -8.2 198 1.0
9750 -0.7 30.7 345 20 10 7.7 4.3 6.3 43.3 -8.3 172 0.9
9500 -0.1 31.8 340 21 11 8.5 4.7 6.2 43.1 -8.5 146 0.7
9250 0.5 32.9 340 23 12 7.6 4.2 6.1 42.9 -8.6 120 0.6
9000 1.0 33.8 335 24 12 3.7 2.0 5.8 42.4 -8.9 99 0.5
8750 1.1 34.0 325 24 12 0.9 0.5 5.2 41.3 -9.5 88 0.4
8500 1.2 34.2 320 25 13 3.0 1.7 4.6 40.2 -10.2 77 0.4
8250 1.3 34.3 315 25 13 -2.6 -1.4 4.0 39.1 -10.8 66 0.3
8000 0.6 33.1 310 24 12 -18.3 -10.1 2.4 36.4 -12.3 82 0.4
7750 -1.3 29.7 300 16 8 -27.8 -15.3 -0.1 31.8 -14.9 129 0.7
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 * * * * * *
02/23/2025 at 0800 MST | 02/23/2025 at 1100 MST
|
CAPE... 0.0 LI... +2.6 | CAPE... 0.0 LI... +5.8
CINH... 0.0 K Index... +1.0 | CINH... 0.0 K Index... -27.0
|
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 -56.8 -70.2 335 36 19 2.2 1.2 | -56.6 -69.9 330 40 21 2.4 1.3
45000 -53.6 -64.5 330 48 25 1.2 0.7 | -53.2 -63.8 335 49 25 -1.7 -0.9
40000 -53.8 -64.8 330 60 31 -0.2 -0.1 | -56.5 -69.7 330 62 32 -2.2 -1.2
38000 -54.1 -65.4 345 62 32 -0.6 -0.3 | -56.8 -70.2 340 62 32 1.3 0.7
36000 -54.4 -65.9 010 73 38 -0.6 -0.3 | -55.9 -68.6 360 62 32 1.3 0.7
34000 -53.8 -64.8 025 88 45 8.8 4.8 | -53.9 -65.0 015 65 33 8.0 4.4
32000 -48.9 -56.0 015 77 39 8.2 4.5 | -49.0 -56.2 015 60 31 8.2 4.5
30000 -44.1 -47.4 010 66 34 6.7 3.7 | -44.1 -47.4 015 57 29 8.3 4.6
29000 -42.1 -43.8 010 62 32 6.8 3.7 | -41.6 -42.9 010 56 29 8.3 4.6
28000 -40.0 -40.0 010 59 30 6.8 3.7 | -39.1 -38.4 005 56 29 8.3 4.6
27000 -38.0 -36.4 010 55 28 6.9 3.8 | -36.5 -33.7 360 55 28 9.4 5.2
26000 -35.9 -32.6 005 53 27 7.1 3.9 | -33.6 -28.5 005 53 27 9.6 5.3
25000 -33.7 -28.7 360 52 27 7.1 3.9 | -30.8 -23.4 005 51 26 9.6 5.3
24000 -31.1 -24.0 355 51 26 6.9 3.8 | -27.9 -18.2 005 49 25 8.6 4.7
23000 -29.1 -20.4 350 48 25 6.8 3.7 | -25.6 -14.1 005 47 24 7.8 4.3
22000 -27.0 -16.6 345 46 24 6.8 3.7 | -23.2 -9.8 005 44 23 7.8 4.3
21000 -25.0 -13.0 340 43 22 6.6 3.6 | -20.5 -4.9 360 41 21 6.6 3.6
20000 -23.0 -9.4 340 38 19 6.6 3.6 | -18.5 -1.3 355 41 21 6.7 3.7
19500 -22.0 -7.6 340 35 18 6.6 3.6 | -17.5 0.5 355 40 21 6.7 3.7
19000 -21.0 -5.8 335 32 17 6.6 3.6 | -16.5 2.3 350 40 21 6.7 3.7
18500 -20.0 -4.0 335 29 15 7.0 3.8 | -15.6 3.9 350 39 20 5.0 2.7
18000 -19.0 -2.2 335 26 13 7.0 3.9 | -14.8 5.4 350 38 20 5.2 2.8
17500 -18.0 -0.4 335 22 12 7.1 3.9 | -14.1 6.6 350 36 19 4.8 2.6
17000 -16.9 1.6 335 21 11 7.3 4.0 | -13.4 7.9 350 34 17 4.6 2.5
16500 -15.8 3.6 340 19 10 7.3 4.0 | -12.7 9.1 350 31 16 4.7 2.6
16000 -14.7 5.5 340 18 9 7.9 4.3 | -12.0 10.4 345 28 14 4.8 2.6
15500 -13.5 7.7 340 16 8 7.9 4.3 | -11.3 11.7 345 24 12 4.7 2.6
15000 -12.3 9.9 345 15 8 8.0 4.4 | -10.5 13.1 340 21 11 6.3 3.5
14500 -11.1 12.0 345 14 7 8.0 4.4 | -9.6 14.7 335 18 9 6.1 3.4
14000 -9.9 14.2 345 13 7 8.0 4.4 | -8.6 16.5 330 16 8 7.0 3.9
13500 -8.8 16.2 345 12 6 8.0 4.4 | -7.6 18.3 325 13 7 7.1 3.9
13000 -7.6 18.3 345 12 6 8.1 4.4 | -6.5 20.3 315 11 6 7.7 4.2
12500 -6.3 20.7 350 10 5 8.4 4.6 | -5.4 22.3 310 10 5 7.4 4.1
12000 -5.1 22.8 345 8 4 7.9 4.3 | -4.3 24.3 295 9 5 7.2 4.0
11750 -4.5 23.9 345 8 4 7.4 4.1 | -3.8 25.2 290 8 4 6.7 3.7
11500 -4.0 24.8 345 8 4 7.8 4.3 | -3.3 26.1 280 8 4 8.4 4.6
11250 -3.4 25.9 345 7 4 8.3 4.6 | -2.5 27.5 270 8 4 10.3 5.7
11000 -2.8 27.0 345 7 4 7.4 4.1 | -1.9 28.6 265 7 4 7.4 4.1
10750 -2.3 27.9 345 7 3 6.8 3.7 | -1.4 29.5 260 7 4 5.7 3.1
10500 -1.8 28.8 345 6 3 6.5 3.5 | -1.0 30.2 250 7 4 5.7 3.1
10250 -1.3 29.7 340 6 3 8.3 4.5 | -0.5 31.1 245 7 4 8.1 4.5
10000 -0.6 30.9 340 7 4 8.7 4.8 | 0.2 32.4 245 7 4 9.3 5.1
9750 -0.0 32.0 340 8 4 7.1 3.9 | 0.8 33.4 245 7 3 7.6 4.2
9500 0.5 32.9 340 9 4 7.4 4.1 | 1.4 34.5 240 6 3 8.4 4.6
9250 1.1 34.0 340 9 5 7.9 4.3 | 2.0 35.6 240 6 3 7.0 3.8
9000 1.7 35.1 335 10 5 6.7 3.7 | 2.5 36.5 240 6 3 8.4 4.6
8750 2.1 35.8 330 11 6 4.4 2.4 | 3.2 37.8 245 6 3 10.6 5.8
8500 2.5 36.5 325 12 6 7.3 4.0 | 3.9 39.0 245 7 3 10.2 5.6
8250 2.8 37.0 320 14 7 -4.1 -2.3 | 4.6 40.3 250 7 3 9.3 5.1
8000 1.7 35.1 310 15 7 -18.3 -10.1 | 5.3 41.5 245 7 4 12.0 6.6
7750 0.5 32.9 295 12 6 -9.9 -5.4 | 6.5 43.7 245 6 3 19.5 10.7
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
02/23/2025 at 1400 MST | 02/23/2025 at 1700 MST
|
CAPE... 0.0 LI... +5.2 | CAPE... 0.0 LI... +5.1
CINH... 0.0 K Index... -30.8 | CINH... 0.0 K Index... -16.5
|
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 -56.6 -69.9 325 41 21 3.2 1.8 | -57.7 -71.9 325 47 24 4.1 2.2
45000 -52.2 -62.0 335 47 24 -4.5 -2.5 | -52.4 -62.3 335 56 29 -4.9 -2.7
40000 -59.9 -75.8 335 64 33 -4.8 -2.7 | -59.5 -75.1 330 50 26 -4.6 -2.5
38000 -59.1 -74.4 340 60 31 4.4 2.4 | -58.5 -73.3 325 53 27 4.6 2.5
36000 -56.5 -69.7 345 52 27 4.4 2.4 | -55.8 -68.4 325 58 30 4.6 2.5
34000 -53.1 -63.6 345 46 24 8.4 4.6 | -52.1 -61.8 325 60 31 8.9 4.9
32000 -48.0 -54.4 345 44 23 8.4 4.6 | -46.1 -51.0 330 55 29 9.0 4.9
30000 -42.9 -45.2 345 43 22 8.8 4.8 | -40.7 -41.3 330 50 26 8.9 4.9
29000 -40.3 -40.5 345 42 22 8.8 4.8 | -38.1 -36.6 330 46 24 8.9 4.9
28000 -37.6 -35.7 350 42 21 8.8 4.8 | -35.4 -31.7 335 43 22 8.9 4.9
27000 -35.1 -31.2 350 40 21 8.0 4.4 | -32.9 -27.2 335 39 20 7.0 3.8
26000 -32.6 -26.7 350 37 19 8.0 4.4 | -30.8 -23.4 335 36 18 7.1 3.9
25000 -30.2 -22.4 350 34 17 8.0 4.4 | -28.7 -19.7 330 32 16 7.1 3.9
24000 -27.8 -18.0 350 31 16 8.5 4.6 | -26.5 -15.7 330 28 15 8.4 4.6
23000 -24.6 -12.3 350 30 15 8.7 4.8 | -23.9 -11.0 325 27 14 8.5 4.6
22000 -22.0 -7.6 345 29 15 8.7 4.8 | -21.4 -6.5 325 25 13 8.5 4.6
21000 -19.3 -2.7 345 29 15 8.9 4.9 | -18.9 -2.0 320 22 11 8.2 4.5
20000 -16.6 2.1 340 31 16 8.9 4.9 | -16.4 2.5 320 18 9 8.2 4.5
19500 -15.3 4.5 340 31 16 8.9 4.9 | -14.6 5.7 320 15 7 8.2 4.5
19000 -14.0 6.8 340 32 16 8.7 4.8 | -13.4 7.9 315 12 6 8.1 4.4
18500 -12.8 9.0 340 33 17 7.2 3.9 | -12.2 10.0 320 13 7 7.9 4.3
18000 -11.7 10.9 340 33 17 7.3 4.0 | -11.0 12.2 320 14 7 8.0 4.4
17500 -10.6 12.9 340 34 17 7.0 3.8 | -9.9 14.2 325 15 8 6.7 3.7
17000 -9.6 14.7 340 33 17 6.9 3.8 | -8.9 16.0 330 16 8 6.6 3.6
16500 -8.5 16.7 345 33 17 6.6 3.6 | -7.9 17.8 330 16 8 6.3 3.5
16000 -7.7 18.1 345 31 16 5.5 3.0 | -7.1 19.2 330 17 9 5.8 3.2
15500 -6.8 19.8 345 30 16 5.7 3.1 | -6.2 20.8 330 18 9 5.8 3.2
15000 -6.1 21.0 345 29 15 4.1 2.3 | -5.5 22.1 325 18 9 4.1 2.3
14500 -5.5 22.1 340 27 14 4.4 2.4 | -4.9 23.2 320 19 10 4.3 2.4
14000 -4.9 23.2 335 25 13 3.5 1.9 | -4.3 24.3 320 20 10 4.1 2.2
13500 -4.4 24.1 330 22 11 3.4 1.9 | -3.8 25.2 320 20 10 4.0 2.2
13000 -3.9 25.0 320 19 10 5.8 3.2 | -3.1 26.4 320 21 11 6.8 3.7
12500 -3.0 26.6 310 18 9 4.6 2.5 | -2.1 28.2 320 22 11 5.2 2.9
12000 -2.4 27.7 300 18 9 5.4 3.0 | -1.4 29.5 320 23 12 5.4 2.9
11750 -2.0 28.4 300 18 9 5.4 3.0 | -1.0 30.2 320 22 11 5.6 3.0
11500 -1.6 29.1 295 17 9 7.5 4.1 | -0.6 30.9 315 21 11 5.0 2.8
11250 -1.0 30.2 290 17 9 10.3 5.6 | -0.3 31.5 310 21 11 4.6 2.5
11000 -0.3 31.5 285 16 8 8.6 4.7 | 0.1 32.2 305 20 10 6.9 3.8
10750 0.3 32.5 280 15 8 7.6 4.2 | 0.7 33.3 300 19 10 8.3 4.6
10500 0.9 33.6 280 14 7 7.6 4.2 | 1.3 34.3 300 19 10 8.0 4.4
10250 1.5 34.7 275 13 7 12.4 6.8 | 1.9 35.4 295 18 9 10.1 5.6
10000 2.6 36.7 275 13 7 11.4 6.3 | 2.7 36.9 295 17 9 10.2 5.6
9750 3.2 37.8 270 12 6 7.2 4.0 | 3.4 38.1 295 17 9 9.0 4.9
9500 3.8 38.8 270 11 5 7.5 4.1 | 4.1 39.4 295 16 8 8.9 4.9
9250 4.4 39.9 265 10 5 10.6 5.8 | 4.8 40.6 295 16 8 10.7 5.8
9000 5.3 41.5 260 9 4 11.6 6.4 | 5.6 42.1 295 15 8 10.6 5.8
8750 6.0 42.8 255 8 4 8.7 4.8 | 6.3 43.3 295 14 7 8.4 4.6
8500 6.7 44.1 250 7 4 9.7 5.3 | 7.0 44.6 295 13 7 9.9 5.4
8250 7.4 45.3 240 6 3 8.7 4.8 | 7.6 45.7 295 12 6 6.2 3.4
8000 8.1 46.6 235 6 3 11.3 6.2 | 7.7 45.9 290 10 5 -1.8 -1.0
7750 9.1 48.4 230 5 2 17.5 9.6 | 7.4 45.3 285 6 3 -4.4 -2.4
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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