Soaring Guidance
Issued by NWS Pueblo, CO
Issued by NWS Pueblo, CO
659
UXUS97 KPUB 141211
SRGPUB
Soaring Forecast
National Weather Service Pueblo, Colorado
0611 MDT Wednesday, May 14, 2025
This forecast is for the Air Force Academy for Wednesday, May 14, 2025:
If the trigger temperature of 57.2 F/14.0 C is reached...then
Thermal Soaring Index....................... Poor
Maximum rate of lift........................ 471 ft/min (2.4 m/s)
Maximum height of thermals.................. 14491 ft MSL (6857 ft AGL)
Forecast maximum temperature................... 71.0 F/22.1 C
Time of trigger temperature.................... 0815 MDT
Time of overdevelopment........................ None
Middle/high clouds during soaring window....... None
Surface winds during soaring window............ More than 30 mph
Height of the -3 thermal index................. 12970 ft MSL (5336 ft AGL)
Thermal soaring outlook for Thursday 05/15..... Excellent
Wave Soaring Index............................. Not available
Remarks...
Sunrise/Sunset.................... 05:46:51 / 20:04:26 MDT
Total possible sunshine........... 14 hr 17 min 35 sec (857 min 35 sec)
Altitude of sun at 12:55:38 MDT... 69.83 degrees
Upper air data from numerical model forecast valid on 05/14/2025 at 0600 MDT
Freezing level.................. 14967 ft MSL (7333 ft AGL)
Convective condensation level... 22462 ft MSL (14828 ft AGL)
Lifted condensation level....... 21323 ft MSL (13689 ft AGL)
Lifted index.................... +1.2
K index......................... -34.4
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 -58.8 -73.8 235 39 20 0.1 0.1 M M M M M
45000 -58.6 -73.5 235 57 29 -0.1 -0.1 M M M M M
40000 -58.8 -73.8 235 49 25 0.1 0.0 M M M M M
38000 -56.1 -69.0 235 49 25 6.0 3.3 M M M M M
36000 -52.5 -62.5 240 49 25 6.0 3.3 M M M M M
34000 -48.4 -55.1 235 45 23 7.9 4.4 M M M M M
32000 -43.7 -46.7 220 37 19 7.9 4.3 M M M M M
30000 -39.0 -38.2 205 32 17 7.6 4.2 29.2 84.6 5.9 M M
29000 -36.7 -34.1 200 32 17 7.6 4.2 28.3 83.0 5.2 M M
28000 -34.4 -29.9 195 32 17 7.6 4.2 27.6 81.7 4.7 M M
27000 -32.1 -25.8 195 32 17 8.6 4.7 27.0 80.5 4.2 M M
26000 -29.5 -21.1 195 32 16 8.7 4.8 26.5 79.6 3.9 M M
25000 -26.2 -15.2 195 31 16 8.7 4.8 26.0 78.8 3.6 M M
24000 -23.6 -10.5 195 31 16 9.2 5.0 25.7 78.3 3.3 M M
23000 -20.8 -5.4 200 31 16 9.1 5.0 25.4 77.7 3.1 M M
22000 -18.1 -0.6 200 31 16 9.1 5.0 25.2 77.4 3.0 M M
21000 -15.4 4.3 200 31 16 8.9 4.9 25.0 77.0 2.9 M M
20000 -12.7 9.1 200 28 14 8.9 4.9 24.7 76.4 2.6 M M
19500 -11.4 11.5 200 27 14 8.9 4.9 24.5 76.1 2.5 M M
19000 -10.0 14.0 200 25 13 8.9 4.9 24.4 75.9 2.4 M M
18500 -8.7 16.3 200 24 12 9.0 4.9 24.3 75.7 2.3 M M
18000 -7.4 18.7 200 23 12 8.9 4.9 24.2 75.5 2.2 M M
17500 -6.0 21.2 200 21 11 8.8 4.8 24.0 75.3 2.1 M M
17000 -4.7 23.5 205 21 11 8.3 4.5 23.8 74.8 1.9 M M
16500 -3.5 25.7 205 21 11 8.3 4.6 23.6 74.4 1.7 M M
16000 -2.3 27.9 210 21 11 7.4 4.1 23.3 73.9 1.4 M M
15500 -1.2 29.8 210 21 11 7.3 4.0 22.9 73.2 1.1 M M
15000 -0.1 31.8 215 21 11 6.2 3.4 22.5 72.5 0.7 M M
14500 0.7 33.3 225 21 11 5.3 2.9 21.7 71.1 0.1 M M
14000 1.5 34.7 230 22 11 4.7 2.6 21.0 69.8 -0.6 436 2.2
13500 2.0 35.6 240 24 13 2.4 1.3 20.0 67.9 -1.6 407 2.1
13000 2.3 36.1 250 27 14 0.5 0.3 18.8 65.9 -2.7 381 1.9
12500 2.1 35.8 260 32 17 -0.8 -0.4 17.1 62.8 -4.4 372 1.9
12000 1.9 35.4 265 36 18 -1.2 -0.7 15.4 59.8 -6.1 363 1.8
11750 1.9 35.4 265 37 19 1.1 0.6 14.6 58.3 -6.9 358 1.8
11500 2.0 35.6 270 38 19 2.9 1.6 14.1 57.3 -7.5 346 1.8
11250 2.2 36.0 270 38 20 2.1 1.2 13.5 56.2 -8.1 335 1.7
11000 2.3 36.1 275 38 20 1.8 1.0 12.9 55.2 -8.8 323 1.6
10750 2.4 36.3 275 38 20 4.4 2.4 12.3 54.1 -9.4 312 1.6
10500 2.9 37.2 280 36 19 7.6 4.2 12.1 53.7 -9.7 290 1.5
10250 3.5 38.3 285 34 17 7.9 4.3 11.9 53.4 -9.9 266 1.4
10000 4.1 39.4 285 33 17 8.3 4.5 11.8 53.2 -10.0 241 1.2
9750 4.7 40.5 285 32 16 8.3 4.6 11.6 53.0 -10.2 215 1.1
9500 5.3 41.5 290 30 16 8.7 4.8 11.6 52.8 -10.3 188 1.0
9250 6.0 42.8 290 29 15 8.2 4.5 11.5 52.6 -10.4 162 0.8
9000 6.5 43.7 290 28 14 7.7 4.2 11.3 52.4 -10.6 137 0.7
8750 7.1 44.8 290 26 14 5.5 3.0 11.1 52.0 -10.8 114 0.6
8500 7.4 45.3 290 25 13 3.4 1.8 10.7 51.2 -11.3 98 0.5
8250 7.6 45.7 290 23 12 5.2 2.9 10.2 50.4 -11.7 81 0.4
8000 7.6 45.7 285 15 8 -13.4 -7.3 8.8 47.8 -13.3 67 0.3
7750 5.9 42.6 280 7 3 -29.4 -16.1 6.4 43.4 -15.7 111 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 * * * * * *
05/14/2025 at 0900 MDT | 05/14/2025 at 1200 MDT
|
CAPE... 0.0 LI... +3.3 | CAPE... 0.0 LI... +4.5
CINH... 0.0 K Index... -18.6 | CINH... 0.0 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 -57.2 -71.0 230 37 19 -0.2 -0.1 | -56.0 -68.8 225 39 20 0.2 0.1
45000 -57.5 -71.5 230 59 30 -0.2 -0.1 | -55.8 -68.4 230 65 33 -0.1 -0.1
40000 -57.9 -72.2 230 55 28 -0.1 -0.1 | -55.9 -68.6 225 75 39 -0.1 -0.0
38000 -55.7 -68.3 230 56 29 5.2 2.9 | -54.2 -65.6 225 77 39 4.3 2.4
36000 -52.6 -62.7 235 58 30 5.2 2.9 | -51.6 -60.9 230 77 40 4.3 2.4
34000 -48.9 -56.0 235 57 29 7.7 4.2 | -48.6 -55.5 230 77 40 6.9 3.8
32000 -44.2 -47.6 230 48 25 7.8 4.3 | -44.4 -47.9 230 74 38 6.9 3.8
30000 -39.6 -39.3 225 42 21 7.8 4.3 | -40.1 -40.2 225 70 36 8.0 4.4
29000 -37.2 -35.0 220 40 21 7.8 4.3 | -37.6 -35.7 225 68 35 8.1 4.4
28000 -34.9 -30.8 210 39 20 7.8 4.3 | -35.2 -31.4 225 65 33 8.1 4.4
27000 -32.5 -26.5 205 39 20 8.1 4.5 | -32.8 -27.0 225 62 32 7.7 4.2
26000 -29.4 -20.9 200 39 20 8.3 4.5 | -30.1 -22.2 220 56 29 7.2 4.0
25000 -27.0 -16.6 200 39 20 8.3 4.5 | -27.9 -18.2 215 51 26 7.2 4.0
24000 -24.4 -11.9 195 39 20 8.8 4.8 | -25.7 -14.3 210 47 24 8.7 4.8
23000 -21.8 -7.2 195 36 19 8.8 4.8 | -22.9 -9.2 205 44 23 9.3 5.1
22000 -19.2 -2.6 200 34 17 8.8 4.8 | -20.1 -4.2 200 42 22 9.4 5.1
21000 -16.5 2.3 200 32 16 9.0 4.9 | -17.4 0.7 195 41 21 7.4 4.1
20000 -13.8 7.2 200 32 16 9.0 4.9 | -15.2 4.6 205 44 23 7.4 4.0
19500 -12.5 9.5 205 32 16 9.0 4.9 | -14.1 6.6 210 46 24 7.4 4.0
19000 -11.1 12.0 205 32 16 9.0 4.9 | -13.0 8.6 215 48 25 7.4 4.0
18500 -9.8 14.4 205 32 16 8.4 4.6 | -11.9 10.6 220 50 26 6.9 3.8
18000 -8.6 16.5 210 33 17 8.2 4.5 | -10.9 12.4 220 51 26 6.6 3.6
17500 -7.3 18.9 210 33 17 8.1 4.4 | -9.9 14.2 220 53 27 6.6 3.6
17000 -6.2 20.8 215 34 17 7.4 4.1 | -9.2 15.4 225 51 26 3.9 2.1
16500 -5.1 22.8 215 34 17 7.5 4.1 | -8.5 16.7 225 48 25 4.2 2.3
16000 -4.0 24.8 220 35 18 6.5 3.6 | -8.0 17.6 230 44 23 3.5 1.9
15500 -3.0 26.6 225 36 18 6.4 3.5 | -7.5 18.5 230 37 19 3.5 1.9
15000 -2.0 28.4 225 37 19 5.6 3.1 | -7.0 19.4 235 30 16 4.8 2.6
14500 -1.3 29.7 230 38 20 4.7 2.6 | -6.1 21.0 235 22 12 6.9 3.8
14000 -0.6 30.9 235 40 21 4.2 2.3 | -5.1 22.8 235 14 7 7.4 4.0
13500 -0.3 31.5 240 40 21 1.1 0.6 | -3.7 25.3 230 10 5 11.2 6.2
13000 -0.1 31.8 245 40 21 1.4 0.8 | -2.0 28.4 220 8 4 6.1 3.4
12500 -0.1 31.8 250 37 19 -0.6 -0.3 | -1.1 30.0 210 7 3 10.7 5.9
12000 -0.2 31.6 260 33 17 -0.7 -0.4 | 0.3 32.5 200 6 3 9.0 5.0
11750 -0.3 31.5 265 32 16 1.3 0.7 | 1.0 33.8 195 6 3 11.6 6.3
11500 -0.1 31.8 265 28 14 4.8 2.6 | 2.0 35.6 195 7 3 11.3 6.2
11250 0.3 32.5 270 25 13 5.7 3.2 | 2.7 36.9 190 7 3 8.5 4.6
11000 0.7 33.3 275 22 11 5.1 2.8 | 3.3 37.9 190 6 3 9.0 4.9
10750 1.1 34.0 280 19 10 7.0 3.8 | 4.0 39.2 185 6 3 9.7 5.3
10500 1.7 35.1 280 16 8 9.2 5.1 | 4.8 40.6 185 7 3 10.6 5.8
10250 2.4 36.3 285 13 7 9.4 5.2 | 5.6 42.1 185 7 3 10.0 5.5
10000 3.1 37.6 285 11 6 9.9 5.4 | 6.3 43.3 180 7 3 9.7 5.3
9750 3.9 39.0 290 10 5 9.8 5.4 | 7.0 44.6 180 7 3 9.9 5.5
9500 4.6 40.3 290 9 4 9.7 5.3 | 7.8 46.0 180 7 3 10.2 5.6
9250 5.3 41.5 290 8 4 9.9 5.4 | 8.6 47.5 175 7 3 10.0 5.5
9000 6.1 43.0 290 7 4 10.2 5.6 | 9.3 48.7 175 7 3 9.5 5.2
8750 6.8 44.2 290 6 3 10.4 5.7 | 10.0 50.0 175 7 3 10.4 5.7
8500 7.6 45.7 290 6 3 10.7 5.9 | 11.7 53.1 170 7 3 10.4 5.7
8250 8.4 47.1 290 6 3 9.9 5.4 | 12.4 54.3 170 7 3 10.8 5.9
8000 9.2 48.6 290 5 3 12.0 6.6 | 13.6 56.5 165 7 3 22.0 12.1
7750 12.0 53.6 290 4 2 22.5 12.3 | 16.3 61.3 165 6 3 57.9 31.7
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
05/14/2025 at 1500 MDT | 05/14/2025 at 1800 MDT
|
CAPE... +17.7 LI... +0.4 | CAPE... +27.9 LI... -0.5
CINH... -0.1 K Index... +10.2 | CINH... -33.2 K Index... +18.2
|
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 -54.8 -66.6 230 30 15 1.6 0.9 | -54.3 -65.7 230 31 16 2.2 1.2
45000 -52.5 -62.5 235 49 25 -0.9 -0.5 | -50.9 -59.6 235 49 25 0.7 0.4
40000 -53.5 -64.3 230 77 39 -0.7 -0.4 | -49.7 -57.5 230 60 31 0.8 0.4
38000 -52.6 -62.7 230 83 43 3.0 1.6 | -48.9 -56.0 230 64 33 1.6 0.9
36000 -50.8 -59.4 230 86 44 3.0 1.6 | -48.0 -54.4 235 69 36 1.6 0.9
34000 -48.6 -55.5 230 88 45 6.4 3.5 | -46.5 -51.7 235 74 38 4.6 2.5
32000 -44.9 -48.8 225 87 45 6.2 3.4 | -43.8 -46.8 235 76 39 4.5 2.5
30000 -41.0 -41.8 225 86 44 7.6 4.2 | -40.7 -41.3 235 77 40 7.9 4.3
29000 -38.7 -37.7 225 85 44 7.6 4.1 | -38.4 -37.1 235 77 40 7.7 4.2
28000 -36.4 -33.5 225 84 43 7.6 4.1 | -36.1 -33.0 235 77 40 7.7 4.2
27000 -33.6 -28.5 225 83 43 7.4 4.1 | -33.8 -28.8 235 77 40 7.7 4.2
26000 -31.4 -24.5 220 79 41 7.4 4.0 | -32.0 -25.6 235 72 37 5.6 3.1
25000 -29.2 -20.6 220 75 39 7.4 4.0 | -30.3 -22.5 235 66 34 5.6 3.1
24000 -27.0 -16.6 215 72 37 7.2 3.9 | -28.6 -19.5 235 59 30 5.7 3.1
23000 -24.9 -12.8 215 67 34 6.7 3.7 | -27.1 -16.8 235 49 25 4.9 2.7
22000 -22.9 -9.2 215 62 32 6.7 3.7 | -25.6 -14.1 230 37 19 4.9 2.7
21000 -20.9 -5.6 215 56 29 6.6 3.6 | -23.8 -10.8 225 22 12 6.5 3.6
20000 -19.0 -2.2 220 49 25 6.6 3.6 | -21.6 -6.9 210 17 9 7.6 4.2
19500 -18.0 -0.4 220 46 24 6.6 3.6 | -20.5 -4.9 200 15 8 7.6 4.2
19000 -17.0 1.4 225 43 22 6.6 3.6 | -19.4 -2.9 190 14 7 7.7 4.2
18500 -16.0 3.2 225 39 20 6.9 3.8 | -18.3 -0.9 175 13 7 8.2 4.5
18000 -15.0 5.0 225 35 18 7.3 4.0 | -17.0 1.4 185 13 7 9.1 5.0
17500 -13.9 7.0 225 30 16 7.3 4.0 | -15.6 3.9 195 14 7 9.4 5.1
17000 -12.8 9.0 225 28 14 8.2 4.5 | -14.4 6.1 200 14 7 6.8 3.7
16500 -11.6 11.1 230 27 14 8.2 4.5 | -13.4 7.9 205 14 7 6.9 3.8
16000 -10.4 13.3 230 26 13 9.1 5.0 | -12.4 9.7 210 14 7 7.6 4.2
15500 -9.0 15.8 225 26 13 9.5 5.2 | -11.2 11.8 220 14 7 8.0 4.4
15000 -7.5 18.5 225 26 13 9.7 5.3 | -10.0 14.0 225 15 8 7.9 4.4
14500 -6.0 21.2 220 26 13 10.0 5.5 | -8.9 16.0 235 15 8 7.4 4.1
14000 -4.5 23.9 220 25 13 9.9 5.4 | -7.8 18.0 245 15 8 7.4 4.1
13500 -2.9 26.8 215 25 13 12.1 6.6 | -6.6 20.1 255 16 8 9.0 4.9
13000 -1.0 30.2 215 26 13 7.9 4.4 | -5.3 22.5 265 17 9 8.7 4.8
12500 -0.1 31.8 210 25 13 9.3 5.1 | -4.6 23.7 275 20 10 3.6 2.0
12000 1.3 34.3 205 25 13 8.7 4.8 | -3.7 25.3 280 23 12 5.8 3.2
11750 2.0 35.6 205 25 13 12.7 7.0 | -3.2 26.2 280 24 12 8.7 4.8
11500 3.1 37.6 205 25 13 12.1 6.6 | -2.4 27.7 285 25 13 9.3 5.1
11250 3.7 38.7 205 25 13 7.7 4.2 | -1.9 28.6 285 25 13 7.2 4.0
11000 4.4 39.9 200 25 13 8.6 4.7 | -1.3 29.7 285 26 13 7.6 4.2
10750 5.0 41.0 200 25 13 9.2 5.1 | -0.8 30.6 290 27 14 8.1 4.4
10500 5.8 42.4 200 25 13 10.6 5.8 | -0.1 31.8 290 27 14 9.0 5.0
10250 6.6 43.9 200 25 13 10.1 5.5 | 0.6 33.1 290 27 14 9.7 5.3
10000 7.3 45.1 200 25 13 9.7 5.3 | 1.3 34.3 290 27 14 10.0 5.5
9750 8.0 46.4 200 25 13 10.0 5.5 | 2.1 35.8 290 27 14 10.1 5.6
9500 8.8 47.8 195 25 13 10.5 5.7 | 2.8 37.0 290 27 14 10.4 5.7
9250 9.6 49.3 195 25 13 10.2 5.6 | 3.6 38.5 290 27 14 10.3 5.7
9000 11.0 51.8 195 25 13 10.5 5.8 | 4.4 39.9 290 27 14 10.1 5.5
8750 11.9 53.4 195 24 13 11.9 6.5 | 5.1 41.2 290 27 14 10.5 5.7
8500 12.8 55.0 195 24 12 12.2 6.7 | 5.9 42.6 290 27 14 11.0 6.0
8250 13.6 56.5 190 24 12 7.9 4.4 | 6.7 44.1 290 27 14 10.4 5.7
8000 14.2 57.6 190 23 12 13.3 7.3 | 7.5 45.5 290 26 13 10.5 5.8
7750 17.4 63.3 190 19 10 92.5 50.8 | 9.9 49.8 290 18 9 26.6 14.6
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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