Soaring Guidance
Issued by NWS Pueblo, CO
Issued by NWS Pueblo, CO
725
UXUS97 KPUB 281213
SRGPUB
Soaring Forecast
National Weather Service Pueblo, Colorado
0613 MDT Friday, June 28, 2024
This forecast is for the Air Force Academy for Friday, June 28, 2024:
If the trigger temperature of 73.3 F/22.9 C is reached...then
Thermal Soaring Index....................... Excellent
Maximum rate of lift........................ 1319 ft/min (6.7 m/s)
Maximum height of thermals.................. 21644 ft MSL (14025 ft AGL)
Forecast maximum temperature................... 88.0 F/31.6 C
Time of trigger temperature.................... 0830 MDT
Time of overdevelopment........................ 1500 MDT
Middle/high clouds during soaring window....... None
Surface winds during soaring window............ 20 mph or less
Height of the -3 thermal index................. 18583 ft MSL (10964 ft AGL)
Thermal soaring outlook for Saturday 06/29..... Excellent
Wave Soaring Index............................. Not available
Remarks...
Sunrise/Sunset.................... 05:36:29 / 20:29:00 MDT
Total possible sunshine........... 14 hr 52 min 31 sec (892 min 31 sec)
Altitude of sun at 13:02:45 MDT... 74.23 degrees
Upper air data from numerical model forecast valid on 06/28/2024 at 0600 MDT
Freezing level.................. 16250 ft MSL (8631 ft AGL)
Convective condensation level... 17340 ft MSL (9721 ft AGL)
Lifted condensation level....... 19226 ft MSL (11608 ft AGL)
Lifted index.................... -4.2
K index......................... +22.3
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 -64.1 -83.4 250 47 24 2.7 1.5 M M M M M
45000 -58.2 -72.8 245 66 34 5.9 3.2 M M M M M
40000 -49.1 -56.4 240 75 39 7.3 4.0 M M M M M
38000 -44.7 -48.5 245 74 38 7.3 4.0 M M M M M
36000 -40.3 -40.5 245 74 38 7.4 4.1 M M M M M
34000 -35.7 -32.3 250 66 34 6.6 3.6 M M M M M
32000 -31.8 -25.2 250 58 30 6.7 3.6 M M M M M
30000 -28.1 -18.6 250 52 27 6.2 3.4 40.7 105.3 7.5 M M
29000 -26.2 -15.2 250 49 25 6.2 3.4 39.4 103.0 6.6 M M
28000 -24.4 -11.9 250 46 24 6.2 3.4 38.3 100.9 5.7 M M
27000 -22.6 -8.7 255 41 21 6.2 3.4 36.8 98.2 4.5 M M
26000 -20.7 -5.3 260 37 19 6.2 3.4 35.4 95.8 3.4 M M
25000 -18.9 -2.0 265 32 17 6.1 3.4 34.2 93.6 2.4 M M
24000 -16.8 1.8 265 30 15 7.7 4.2 33.3 91.9 1.6 M M
23000 -14.6 5.7 265 28 14 7.7 4.2 32.5 90.6 0.9 M M
22000 -12.3 9.9 260 25 13 7.9 4.3 31.9 89.4 0.3 M M
21000 -9.8 14.4 265 22 11 6.7 3.7 30.7 87.2 -0.8 1250 6.3
20000 -7.8 18.0 275 20 10 6.8 3.7 29.6 85.4 -1.7 1161 5.9
19500 -6.8 19.8 275 19 10 6.8 3.7 29.2 84.5 -2.2 1117 5.7
19000 -5.8 21.6 280 18 9 6.5 3.6 28.7 83.6 -2.6 1073 5.4
18500 -4.9 23.2 280 17 9 6.6 3.6 28.1 82.6 -3.2 1029 5.2
18000 -3.9 25.0 280 16 8 7.1 3.9 27.6 81.7 -3.7 986 5.0
17500 -2.8 27.0 275 15 8 8.2 4.5 27.3 81.1 -4.0 937 4.8
17000 -1.6 29.1 270 14 7 8.3 4.5 27.0 80.7 -4.3 887 4.5
16500 -0.5 31.1 265 13 7 7.5 4.1 26.7 80.1 -4.7 838 4.3
16000 0.6 33.1 260 13 6 7.6 4.2 26.4 79.5 -5.1 791 4.0
15500 1.7 35.1 255 12 6 7.7 4.2 26.0 78.9 -5.5 744 3.8
15000 2.8 37.0 255 10 5 7.7 4.2 25.7 78.3 -5.9 697 3.5
14500 3.9 39.0 250 9 5 7.8 4.3 25.4 77.7 -6.3 649 3.3
14000 5.0 41.0 255 8 4 7.9 4.4 25.1 77.1 -6.6 600 3.0
13500 6.2 43.2 260 8 4 7.7 4.2 24.8 76.6 -6.9 549 2.8
13000 7.6 45.7 270 7 4 9.3 5.1 24.7 76.4 -7.1 495 2.5
12500 8.8 47.8 285 6 3 7.6 4.2 24.4 75.9 -7.4 444 2.3
12000 9.9 49.8 300 6 3 8.0 4.4 24.1 75.3 -7.7 394 2.0
11750 10.5 50.9 305 6 3 8.4 4.6 23.9 75.1 -7.8 368 1.9
11500 11.2 52.2 310 7 3 9.4 5.2 23.9 75.0 -7.9 341 1.7
11250 11.9 53.4 315 7 4 9.2 5.1 23.9 74.9 -7.9 312 1.6
11000 12.6 54.7 320 8 4 8.2 4.5 23.8 74.8 -8.0 286 1.5
10750 13.1 55.6 320 8 4 7.8 4.3 23.6 74.5 -8.2 261 1.3
10500 13.7 56.7 320 9 4 8.0 4.4 23.5 74.3 -8.4 236 1.2
10250 14.3 57.7 320 9 5 8.0 4.4 23.4 74.0 -8.5 211 1.1
10000 14.9 58.8 315 10 5 7.7 4.2 23.2 73.8 -8.7 186 0.9
9750 15.4 59.7 315 12 6 7.4 4.1 23.0 73.5 -8.9 163 0.8
9500 15.9 60.6 315 13 7 8.1 4.4 22.9 73.2 -9.1 140 0.7
9250 16.5 61.7 315 15 8 5.8 3.2 22.7 72.9 -9.3 116 0.6
9000 16.7 62.1 310 15 7 3.9 2.1 22.3 72.1 -9.8 101 0.5
8750 17.0 62.6 305 15 8 4.1 2.3 21.9 71.4 -10.3 85 0.4
8500 17.3 63.1 300 15 8 5.9 3.2 21.5 70.7 -10.8 70 0.4
8250 17.6 63.7 295 16 8 -1.2 -0.7 21.1 70.0 -11.3 54 0.3
8000 16.8 62.2 290 16 8 -18.4 -10.1 19.6 67.3 -12.8 70 0.4
7750 15.0 59.0 285 12 6 -25.0 -13.7 17.1 62.8 -15.4 117 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 * * * * * *
06/28/2024 at 0900 MDT | 06/28/2024 at 1200 MDT
|
CAPE... +348.8 LI... -2.3 | CAPE... +234.3 LI... -1.2
CINH... -66.8 K Index... +24.9 | CINH... -13.9 K Index... +19.1
|
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 -64.3 -83.7 245 49 25 2.9 1.6 | -64.6 -84.3 245 58 30 3.0 1.7
45000 -58.1 -72.6 250 70 36 6.0 3.3 | -58.2 -72.8 250 74 38 6.1 3.4
40000 -48.9 -56.0 245 77 39 7.4 4.0 | -48.8 -55.8 245 79 41 6.9 3.8
38000 -44.4 -47.9 250 75 39 7.4 4.0 | -44.7 -48.5 245 76 39 6.9 3.8
36000 -40.0 -40.0 250 74 38 7.5 4.1 | -40.6 -41.1 250 72 37 7.0 3.8
34000 -35.9 -32.6 250 63 32 6.0 3.3 | -36.7 -34.1 250 60 31 5.6 3.1
32000 -32.3 -26.1 250 51 26 5.9 3.2 | -33.4 -28.1 255 48 25 5.4 3.0
30000 -28.5 -19.3 250 42 22 6.4 3.5 | -29.2 -20.6 260 42 21 7.3 4.0
29000 -26.6 -15.9 255 39 20 6.5 3.5 | -27.0 -16.6 265 39 20 7.3 4.0
28000 -24.7 -12.5 255 35 18 6.4 3.5 | -24.8 -12.6 270 37 19 7.2 3.9
27000 -22.8 -9.0 255 35 18 6.3 3.5 | -22.7 -8.9 265 38 19 7.1 3.9
26000 -20.9 -5.6 255 35 18 6.3 3.5 | -20.6 -5.1 265 38 20 7.1 3.9
25000 -19.0 -2.2 255 35 18 6.3 3.5 | -18.5 -1.3 265 38 20 7.2 4.0
24000 -17.2 1.0 255 35 18 6.3 3.5 | -16.6 2.1 265 37 19 6.3 3.4
23000 -15.4 4.3 250 34 17 6.4 3.5 | -14.7 5.5 260 36 19 6.3 3.5
22000 -13.5 7.7 250 33 17 6.6 3.6 | -12.8 9.0 255 35 18 6.2 3.4
21000 -11.1 12.0 250 31 16 6.9 3.8 | -10.3 13.5 255 31 16 7.2 4.0
20000 -9.1 15.6 255 29 15 7.0 3.8 | -8.3 17.1 250 28 15 7.4 4.1
19500 -8.1 17.4 255 28 14 6.9 3.8 | -7.3 18.9 245 27 14 7.6 4.1
19000 -7.0 19.4 255 27 14 8.3 4.6 | -6.1 21.0 250 26 13 8.0 4.4
18500 -5.8 21.6 255 25 13 8.2 4.5 | -4.9 23.2 255 25 13 8.0 4.4
18000 -4.6 23.7 260 24 12 8.0 4.4 | -3.7 25.3 260 25 13 7.8 4.3
17500 -3.4 25.9 260 22 12 7.9 4.3 | -2.6 27.3 270 26 13 7.6 4.2
17000 -2.2 28.0 260 21 11 7.8 4.3 | -1.5 29.3 280 27 14 7.6 4.2
16500 -1.1 30.0 260 20 10 8.4 4.6 | -0.3 31.5 285 28 14 7.5 4.1
16000 0.2 32.4 265 18 9 8.4 4.6 | 0.8 33.4 290 29 15 7.6 4.1
15500 1.4 34.5 265 17 9 8.6 4.7 | 1.9 35.4 290 30 15 7.8 4.3
15000 2.7 36.9 270 16 8 8.7 4.7 | 3.1 37.6 295 29 15 7.9 4.4
14500 4.0 39.2 270 15 8 8.6 4.7 | 4.3 39.7 295 29 15 8.0 4.4
14000 5.2 41.4 275 15 8 8.6 4.7 | 5.5 41.9 295 28 15 8.3 4.5
13500 6.4 43.5 280 15 8 8.5 4.6 | 6.6 43.9 295 28 14 8.3 4.6
13000 7.9 46.2 280 16 8 9.4 5.2 | 8.0 46.4 295 28 14 9.8 5.4
12500 8.9 48.0 285 17 9 6.1 3.4 | 9.2 48.6 295 26 13 8.1 4.5
12000 9.8 49.6 285 19 10 7.3 4.0 | 10.4 50.7 295 23 12 9.1 5.0
11750 10.3 50.5 290 20 10 6.7 3.7 | 11.0 51.8 290 21 11 9.5 5.2
11500 10.8 51.4 290 21 11 5.5 3.0 | 11.8 53.2 290 19 10 10.7 5.8
11250 11.1 52.0 290 22 12 4.9 2.7 | 12.5 54.5 290 18 9 9.9 5.4
11000 11.5 52.7 295 24 12 4.6 2.5 | 13.2 55.8 290 17 9 9.0 4.9
10750 11.8 53.2 295 25 13 4.7 2.6 | 13.9 57.0 290 16 8 8.5 4.7
10500 12.1 53.8 295 27 14 4.0 2.2 | 14.5 58.1 285 16 8 10.2 5.6
10250 12.3 54.1 300 28 15 4.2 2.3 | 15.4 59.7 285 15 8 11.5 6.3
10000 12.7 54.9 300 28 15 6.5 3.6 | 16.1 61.0 285 15 8 9.9 5.5
9750 13.2 55.8 300 28 14 7.3 4.0 | 16.9 62.4 285 14 7 9.7 5.3
9500 13.6 56.5 300 27 14 7.0 3.8 | 17.6 63.7 285 14 7 9.6 5.3
9250 14.1 57.4 305 26 13 7.5 4.1 | 18.3 64.9 285 13 7 10.3 5.6
9000 14.7 58.5 305 24 12 9.4 5.1 | 19.1 66.4 285 12 6 10.6 5.8
8750 15.4 59.7 305 23 12 10.5 5.8 | 19.8 67.6 285 12 6 10.4 5.7
8500 16.2 61.2 305 22 11 9.7 5.3 | 20.6 69.1 285 12 6 9.9 5.4
8250 16.9 62.4 305 21 11 11.8 6.5 | 21.4 70.5 285 11 6 12.1 6.7
8000 19.3 66.7 305 16 8 19.5 10.7 | 22.5 72.5 285 11 5 20.1 11.0
7750 20.6 69.1 305 13 7 16.6 9.1 | 24.3 75.7 285 10 5 26.3 14.4
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
06/28/2024 at 1500 MDT | 06/28/2024 at 1800 MDT
|
CAPE... +466.6 LI... -2.0 | CAPE... +720.0 LI... -3.2
CINH... -2.5 K Index... +32.4 | CINH... -5.2 K Index... +32.8
|
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 -64.4 -83.9 250 64 33 2.4 1.3 | -64.3 -83.7 255 65 33 2.1 1.1
45000 -59.1 -74.4 255 83 43 6.2 3.4 | -59.0 -74.2 260 85 44 5.9 3.2
40000 -49.3 -56.7 250 85 44 6.4 3.5 | -50.2 -58.4 255 87 45 6.2 3.4
38000 -45.4 -49.7 250 79 41 6.4 3.5 | -46.4 -51.5 255 77 40 6.3 3.4
36000 -41.5 -42.7 250 72 37 6.4 3.5 | -42.7 -44.9 260 68 35 6.2 3.4
34000 -37.9 -36.2 255 62 32 6.1 3.3 | -38.1 -36.6 260 59 30 6.9 3.8
32000 -34.2 -29.6 260 52 27 6.0 3.3 | -34.0 -29.2 265 51 26 6.8 3.7
30000 -30.0 -22.0 260 47 24 7.2 4.0 | -29.7 -21.5 265 45 23 7.3 4.0
29000 -27.9 -18.2 260 45 23 7.2 4.0 | -27.5 -17.5 265 43 22 7.3 4.0
28000 -25.7 -14.3 265 43 22 7.4 4.1 | -25.3 -13.5 265 40 21 7.9 4.4
27000 -23.4 -10.1 265 42 22 7.8 4.3 | -22.8 -9.0 265 38 20 8.2 4.5
26000 -21.1 -6.0 260 41 21 7.8 4.3 | -20.4 -4.7 265 37 19 8.2 4.5
25000 -18.2 -0.8 260 40 21 7.2 4.0 | -17.9 -0.2 260 35 18 8.3 4.5
24000 -16.5 2.3 260 37 19 6.0 3.3 | -16.2 2.8 265 33 17 5.5 3.0
23000 -14.8 5.4 260 34 17 6.0 3.3 | -14.6 5.7 265 31 16 5.6 3.1
22000 -13.0 8.6 260 31 16 7.0 3.8 | -13.0 8.6 270 29 15 5.8 3.2
21000 -10.7 12.7 265 29 15 8.1 4.4 | -10.5 13.1 270 28 15 7.4 4.1
20000 -8.4 16.9 265 26 14 8.1 4.5 | -8.4 16.9 270 27 14 7.5 4.1
19500 -7.2 19.0 265 25 13 8.2 4.5 | -7.3 18.9 270 27 14 7.6 4.2
19000 -6.1 21.0 270 23 12 7.9 4.3 | -6.2 20.8 270 27 14 7.9 4.4
18500 -4.9 23.2 265 20 11 7.9 4.4 | -5.1 22.8 270 26 13 8.0 4.4
18000 -3.8 25.2 265 18 9 7.6 4.2 | -3.9 25.0 270 25 13 8.3 4.5
17500 -2.7 27.1 270 15 8 7.3 4.0 | -2.8 27.0 275 24 12 8.4 4.6
17000 -1.7 28.9 270 13 7 7.1 3.9 | -1.6 29.1 275 22 11 8.5 4.7
16500 -0.4 31.3 275 12 6 9.4 5.2 | -0.3 31.5 275 20 11 9.4 5.2
16000 0.9 33.6 275 11 6 9.2 5.0 | 1.1 34.0 280 19 10 9.4 5.1
15500 2.3 36.1 275 11 6 9.6 5.3 | 2.5 36.5 280 17 9 9.6 5.3
15000 3.8 38.8 280 10 5 9.7 5.3 | 3.9 39.0 280 17 9 9.6 5.3
14500 5.2 41.4 280 10 5 9.8 5.4 | 5.3 41.5 280 17 9 9.6 5.3
14000 6.7 44.1 280 10 5 9.8 5.4 | 6.8 44.2 285 17 9 9.6 5.3
13500 8.2 46.8 275 10 5 9.8 5.4 | 8.2 46.8 285 16 8 9.9 5.5
13000 9.9 49.8 275 9 5 11.1 6.1 | 9.9 49.8 285 16 8 10.5 5.8
12500 11.2 52.2 275 9 5 8.6 4.7 | 11.2 52.2 285 15 8 8.8 4.8
12000 12.6 54.7 275 9 4 9.6 5.2 | 12.5 54.5 290 14 7 9.1 5.0
11750 13.3 55.9 275 8 4 9.6 5.3 | 13.2 55.8 290 14 7 9.3 5.1
11500 14.0 57.2 275 8 4 10.0 5.5 | 13.9 57.0 290 13 7 9.9 5.5
11250 14.8 58.6 275 8 4 9.7 5.3 | 14.6 58.3 290 13 7 9.2 5.0
11000 15.5 59.9 275 8 4 9.3 5.1 | 15.3 59.5 290 12 6 8.6 4.7
10750 16.2 61.2 275 8 4 9.0 5.0 | 15.9 60.6 290 12 6 8.0 4.4
10500 16.9 62.4 275 7 4 10.0 5.5 | 16.5 61.7 290 11 6 10.4 5.7
10250 17.7 63.9 275 7 4 10.7 5.9 | 17.4 63.3 290 10 5 11.4 6.3
10000 18.4 65.1 275 7 4 9.9 5.4 | 18.1 64.6 295 10 5 9.0 4.9
9750 19.1 66.4 275 7 3 9.8 5.4 | 18.8 65.8 295 8 4 9.1 5.0
9500 19.9 67.8 275 7 3 9.7 5.3 | 19.5 67.1 295 7 4 8.7 4.8
9250 20.6 69.1 275 6 3 10.2 5.6 | 20.2 68.4 300 6 3 10.6 5.8
9000 21.4 70.5 275 6 3 10.3 5.7 | 21.0 69.8 300 6 3 11.1 6.1
8750 22.2 72.0 275 6 3 10.1 5.6 | 21.7 71.1 305 5 3 9.7 5.3
8500 22.9 73.2 275 6 3 9.9 5.4 | 22.4 72.3 310 4 2 10.0 5.5
8250 23.7 74.7 275 5 3 11.2 6.1 | 23.2 73.8 315 4 2 10.1 5.5
8000 24.6 76.3 270 5 3 15.8 8.7 | 24.0 75.2 325 3 1 12.9 7.1
7750 25.9 78.6 270 5 2 19.4 10.7 | 26.2 79.2 360 2 1 10.2 5.6
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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