Soaring Guidance
Issued by NWS Pueblo, CO
Issued by NWS Pueblo, CO
965
UXUS97 KPUB 171233
SRGPUB
Soaring Forecast
National Weather Service Pueblo, Colorado
0633 MDT Tuesday, September 17, 2024
This forecast is for the Air Force Academy for Tuesday, September 17, 2024:
If the trigger temperature of 70.9 F/21.6 C is reached...then
Thermal Soaring Index....................... Good
Maximum rate of lift........................ 726 ft/min (3.7 m/s)
Maximum height of thermals.................. 17517 ft MSL (9915 ft AGL)
Forecast maximum temperature................... 79.0 F/26.6 C
Time of trigger temperature.................... 1000 MDT
Time of overdevelopment........................ 1400 MDT
Middle/high clouds during soaring window....... Broken/overcast thin middle
Surface winds during soaring window............ 20 mph or less
Height of the -3 thermal index................. 12945 ft MSL (5343 ft AGL)
Thermal soaring outlook for Wednesday 09/18.... Excellent
Wave Soaring Index............................. Not available
Remarks...
Sunrise/Sunset.................... 06:43:16 / 19:03:46 MDT
Total possible sunshine........... 12 hr 20 min 29 sec (740 min 29 sec)
Altitude of sun at 12:53:31 MDT... 52.83 degrees
Upper air data from numerical model forecast valid on 09/17/2024 at 0600 MDT
Freezing level.................. 15914 ft MSL (8312 ft AGL)
Convective condensation level... 16064 ft MSL (8462 ft AGL)
Lifted condensation level....... 16589 ft MSL (8987 ft AGL)
Lifted index.................... -4.6
K index......................... +23.9
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 -63.2 -81.8 245 56 29 0.4 0.2 M M M M M
45000 -61.1 -78.0 250 72 37 4.4 2.4 M M M M M
40000 -53.7 -64.7 250 66 34 7.6 4.2 M M M M M
38000 -49.1 -56.4 245 62 32 7.7 4.2 M M M M M
36000 -44.5 -48.1 240 59 30 7.7 4.2 M M M M M
34000 -40.1 -40.2 235 55 28 7.2 4.0 M M M M M
32000 -35.7 -32.3 230 51 26 7.2 4.0 M M M M M
30000 -31.8 -25.2 230 47 24 6.2 3.4 36.8 98.2 8.3 M M
29000 -29.9 -21.8 230 44 23 6.2 3.4 35.4 95.8 7.4 M M
28000 -28.1 -18.6 230 42 22 6.4 3.5 34.2 93.6 6.5 M M
27000 -25.7 -14.3 225 40 21 8.3 4.5 33.5 92.3 5.9 M M
26000 -23.2 -9.8 225 39 20 8.3 4.5 32.9 91.2 5.5 M M
25000 -20.8 -5.4 225 37 19 8.3 4.6 32.4 90.4 5.2 M M
24000 -18.3 -0.9 220 35 18 8.0 4.4 31.8 89.3 4.7 M M
23000 -15.3 4.5 220 32 16 8.1 4.4 31.0 87.9 4.1 M M
22000 -12.9 8.8 215 30 15 7.7 4.2 30.5 87.0 3.7 M M
21000 -11.0 12.2 215 27 14 6.5 3.5 29.4 84.9 2.6 M M
20000 -9.2 15.4 210 24 12 6.7 3.7 28.3 82.9 1.5 M M
19500 -8.3 17.1 210 22 11 6.8 3.7 27.8 82.0 1.0 M M
19000 -7.3 18.9 210 21 11 8.6 4.7 27.5 81.4 0.6 M M
18500 -6.0 21.2 215 21 11 8.6 4.7 27.3 81.1 0.5 M M
18000 -4.7 23.5 215 22 11 8.3 4.5 27.1 80.8 0.3 M M
17500 -3.6 25.5 220 22 11 7.3 4.0 26.7 80.1 -0.0 921 4.7
17000 -2.5 27.5 220 22 11 7.3 4.0 26.3 79.4 -0.4 874 4.4
16500 -1.4 29.5 220 22 11 8.2 4.5 26.0 78.8 -0.8 825 4.2
16000 -0.2 31.6 225 21 11 8.2 4.5 25.7 78.3 -1.0 774 3.9
15500 1.0 33.8 225 21 11 7.9 4.3 25.5 77.9 -1.3 723 3.7
15000 2.2 36.0 225 21 11 7.6 4.1 25.1 77.2 -1.7 675 3.4
14500 3.3 37.9 225 21 11 7.6 4.2 24.8 76.6 -2.0 627 3.2
14000 4.4 39.9 230 21 11 7.8 4.3 24.5 76.0 -2.3 578 2.9
13500 5.6 42.1 230 21 11 7.8 4.3 24.1 75.5 -2.7 529 2.7
13000 6.7 44.1 230 21 11 8.1 4.4 23.9 75.0 -2.9 478 2.4
12500 7.8 46.0 230 22 11 6.9 3.8 23.5 74.3 -3.3 431 2.2
12000 8.8 47.8 235 23 12 6.6 3.6 23.0 73.5 -3.8 386 2.0
11750 9.3 48.7 235 23 12 6.5 3.5 22.8 73.0 -4.1 364 1.8
11500 9.8 49.6 230 24 12 5.9 3.2 22.5 72.5 -4.4 343 1.7
11250 10.2 50.4 230 24 13 5.3 2.9 22.2 71.9 -4.7 324 1.6
11000 10.5 50.9 230 25 13 4.8 2.7 21.8 71.3 -5.1 306 1.6
10750 10.8 51.4 230 25 13 4.5 2.5 21.4 70.6 -5.5 289 1.5
10500 11.1 52.0 230 26 13 5.2 2.8 21.0 69.9 -6.0 273 1.4
10250 11.5 52.7 230 26 14 6.0 3.3 20.7 69.3 -6.3 254 1.3
10000 11.9 53.4 230 27 14 5.0 2.8 20.4 68.7 -6.7 236 1.2
9750 12.2 54.0 230 27 14 4.4 2.4 20.0 68.0 -7.2 220 1.1
9500 12.5 54.5 230 27 14 4.4 2.4 19.6 67.3 -7.6 203 1.0
9250 12.8 55.0 230 27 14 5.0 2.8 19.2 66.6 -8.1 187 1.0
9000 13.1 55.6 235 26 13 5.4 3.0 18.9 66.0 -8.5 170 0.9
8750 13.4 56.1 230 25 13 4.6 2.5 18.5 65.3 -8.9 152 0.8
8500 13.8 56.8 230 24 12 6.0 3.3 18.1 64.7 -9.4 135 0.7
8250 14.1 57.4 230 23 12 1.5 0.8 17.8 64.0 -9.8 118 0.6
8000 13.7 56.7 230 20 10 -11.0 -6.0 16.7 62.1 -10.9 122 0.6
7750 12.5 54.5 230 13 7 -18.2 -10.0 14.8 58.6 -12.8 150 0.8
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 * * * * * *
09/17/2024 at 0900 MDT | 09/17/2024 at 1200 MDT
|
CAPE... +319.8 LI... -1.3 | CAPE... +438.5 LI... -1.7
CINH... -118.4 K Index... +12.5 | CINH... -21.7 K Index... -0.7
|
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 -62.3 -80.1 245 58 30 0.9 0.5 | -61.7 -79.1 235 52 27 1.2 0.7
45000 -59.9 -75.8 245 76 39 3.6 2.0 | -59.0 -74.2 240 76 39 3.6 2.0
40000 -53.8 -64.8 245 68 35 7.4 4.0 | -53.0 -63.4 240 78 40 6.4 3.5
38000 -49.4 -56.9 240 62 32 7.3 4.0 | -49.2 -56.6 235 70 36 6.3 3.4
36000 -44.9 -48.8 235 57 29 7.3 4.0 | -45.4 -49.7 225 64 33 6.3 3.5
34000 -40.5 -40.9 230 54 28 7.5 4.1 | -40.8 -41.4 225 62 32 8.0 4.4
32000 -35.9 -32.6 225 53 27 7.5 4.1 | -36.0 -32.8 220 61 32 8.0 4.4
30000 -31.9 -25.4 225 49 25 6.4 3.5 | -31.9 -25.4 220 59 30 6.4 3.5
29000 -30.0 -22.0 220 48 24 6.4 3.5 | -29.9 -21.8 215 57 29 6.4 3.5
28000 -28.1 -18.6 220 46 24 6.5 3.5 | -28.0 -18.4 215 55 28 6.3 3.4
27000 -25.7 -14.3 220 44 23 8.2 4.5 | -25.7 -14.3 210 52 27 8.0 4.4
26000 -23.3 -9.9 215 43 22 8.2 4.5 | -23.3 -9.9 210 50 26 8.0 4.4
25000 -20.8 -5.4 210 42 22 8.2 4.5 | -20.9 -5.6 205 48 25 7.9 4.4
24000 -18.0 -0.4 210 40 21 7.4 4.1 | -18.1 -0.6 200 45 23 7.0 3.9
23000 -15.7 3.7 205 37 19 7.4 4.1 | -16.0 3.2 200 42 22 7.1 3.9
22000 -13.5 7.7 205 35 18 7.3 4.0 | -13.9 7.0 195 40 21 7.1 3.9
21000 -11.5 11.3 200 32 17 6.6 3.6 | -11.8 10.8 195 38 20 6.9 3.8
20000 -9.6 14.7 200 29 15 6.6 3.6 | -9.8 14.4 195 36 19 6.9 3.8
19500 -8.6 16.5 200 28 14 6.6 3.6 | -8.8 16.2 195 35 18 6.9 3.8
19000 -7.6 18.3 200 26 13 7.8 4.3 | -7.7 18.1 195 34 17 8.2 4.5
18500 -6.5 20.3 205 25 13 7.9 4.4 | -6.4 20.5 195 31 16 8.5 4.7
18000 -5.3 22.5 205 24 12 8.1 4.4 | -5.1 22.8 195 27 14 8.5 4.7
17500 -4.1 24.6 205 23 12 8.3 4.6 | -3.8 25.2 200 27 14 8.3 4.5
17000 -2.8 27.0 205 23 12 8.3 4.6 | -2.6 27.3 200 28 14 8.3 4.6
16500 -1.6 29.1 210 22 12 8.4 4.6 | -1.4 29.5 205 28 15 7.8 4.3
16000 -0.3 31.5 210 23 12 8.4 4.6 | -0.2 31.6 210 29 15 7.7 4.2
15500 0.9 33.6 210 23 12 7.9 4.3 | 0.9 33.6 210 30 15 7.3 4.0
15000 2.0 35.6 215 23 12 7.5 4.1 | 1.9 35.4 210 30 16 6.6 3.6
14500 3.1 37.6 215 24 12 7.5 4.1 | 2.8 37.0 215 31 16 6.7 3.7
14000 4.2 39.6 220 24 13 7.7 4.2 | 3.7 38.7 215 31 16 6.1 3.3
13500 5.3 41.5 225 25 13 7.6 4.2 | 4.5 40.1 215 32 17 6.0 3.3
13000 6.5 43.7 225 26 13 8.4 4.6 | 5.5 41.9 220 33 17 7.8 4.3
12500 7.5 45.5 225 27 14 6.7 3.6 | 6.3 43.3 220 32 17 5.2 2.8
12000 8.4 47.1 225 28 15 6.4 3.5 | 7.0 44.6 220 31 16 7.2 3.9
11750 8.9 48.0 230 29 15 6.5 3.6 | 7.5 45.5 220 30 15 8.0 4.4
11500 9.4 48.9 230 28 15 7.0 3.8 | 8.1 46.6 220 29 15 8.9 4.9
11250 9.9 49.8 230 28 14 6.7 3.7 | 8.7 47.7 220 27 14 9.2 5.1
11000 10.3 50.5 230 27 14 5.8 3.2 | 9.3 48.7 220 25 13 8.7 4.7
10750 10.7 51.3 230 26 14 5.2 2.9 | 9.9 49.8 215 24 12 8.1 4.4
10500 11.1 52.0 230 26 13 6.4 3.5 | 10.5 50.9 215 22 11 9.4 5.2
10250 11.6 52.9 230 25 13 7.7 4.2 | 11.3 52.3 210 21 11 11.5 6.3
10000 12.1 53.8 230 25 13 5.9 3.3 | 12.1 53.8 210 21 11 10.5 5.8
9750 12.4 54.3 230 24 12 4.9 2.7 | 12.8 55.0 210 20 10 9.6 5.3
9500 12.8 55.0 230 23 12 5.1 2.8 | 13.6 56.5 205 20 10 9.6 5.3
9250 13.1 55.6 230 22 11 5.4 3.0 | 14.3 57.7 205 20 10 10.6 5.8
9000 13.4 56.1 235 21 11 5.0 2.7 | 15.1 59.2 205 19 10 10.9 6.0
8750 13.6 56.5 235 21 11 4.5 2.5 | 15.8 60.4 205 19 10 10.3 5.6
8500 13.9 57.0 235 20 10 4.0 2.2 | 16.6 61.9 200 19 10 10.0 5.5
8250 14.2 57.6 235 20 10 6.9 3.8 | 17.4 63.3 200 19 10 11.8 6.5
8000 14.9 58.8 230 16 8 13.5 7.4 | 18.5 65.3 200 18 9 19.7 10.8
7750 16.0 60.8 225 13 7 15.6 8.5 | 20.3 68.5 200 17 9 27.0 14.8
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
09/17/2024 at 1500 MDT | 09/17/2024 at 1800 MDT
|
CAPE... +594.0 LI... -1.5 | CAPE... +456.2 LI... -1.2
CINH... -2.2 K Index... +29.3 | CINH... -11.5 K Index... +11.9
|
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 -60.8 -77.4 240 50 26 2.6 1.4 | -61.3 -78.3 235 44 23 2.6 1.5
45000 -57.5 -71.5 245 81 42 0.3 0.1 | -56.9 -70.4 240 63 33 3.8 2.1
40000 -56.6 -69.9 240 100 51 9.1 5.0 | -50.8 -59.4 230 74 38 4.8 2.6
38000 -51.7 -61.1 235 92 47 8.1 4.4 | -47.9 -54.2 230 73 38 4.7 2.6
36000 -46.9 -52.4 230 84 43 8.1 4.4 | -45.1 -49.2 225 72 37 4.7 2.6
34000 -41.9 -43.4 225 78 40 8.5 4.7 | -41.4 -42.5 220 71 37 6.8 3.7
32000 -36.8 -34.2 220 73 38 8.6 4.7 | -37.4 -35.3 215 70 36 6.8 3.7
30000 -30.9 -23.6 215 64 33 8.9 4.9 | -32.9 -27.2 210 69 35 7.8 4.3
29000 -28.3 -18.9 210 59 31 8.9 4.9 | -30.6 -23.1 205 68 35 7.8 4.3
28000 -25.6 -14.1 210 55 28 8.8 4.8 | -28.3 -18.9 205 68 35 7.7 4.2
27000 -23.1 -9.6 205 52 27 8.3 4.5 | -25.8 -14.4 200 65 34 8.6 4.7
26000 -20.7 -5.3 205 50 26 8.3 4.6 | -23.2 -9.8 195 61 31 8.7 4.8
25000 -18.3 -0.9 205 48 25 8.4 4.6 | -20.7 -5.3 190 58 30 8.8 4.8
24000 -16.2 2.8 205 47 24 6.4 3.5 | -18.3 -0.9 190 56 29 7.2 3.9
23000 -14.3 6.3 205 47 24 6.4 3.5 | -15.5 4.1 195 56 29 7.2 4.0
22000 -12.5 9.5 205 47 24 6.4 3.5 | -13.4 7.9 200 56 29 7.3 4.0
21000 -10.6 12.9 205 47 24 6.3 3.5 | -11.4 11.5 205 57 29 6.5 3.6
20000 -8.8 16.2 205 46 24 6.4 3.5 | -9.5 14.9 210 57 30 6.6 3.6
19500 -7.9 17.8 205 46 24 6.4 3.5 | -8.5 16.7 215 58 30 6.6 3.6
19000 -7.0 19.4 205 45 23 6.2 3.4 | -7.5 18.5 215 59 30 6.1 3.3
18500 -6.1 21.0 200 45 23 5.4 3.0 | -6.7 19.9 220 59 31 5.6 3.1
18000 -5.4 22.3 200 44 23 5.4 3.0 | -5.8 21.6 220 60 31 5.5 3.0
17500 -4.5 23.9 200 43 22 6.3 3.4 | -4.9 23.2 225 60 31 6.3 3.5
17000 -3.6 25.5 200 43 22 6.5 3.6 | -3.9 25.0 225 61 31 6.4 3.5
16500 -2.7 27.1 200 42 21 6.5 3.6 | -2.9 26.8 230 61 31 6.0 3.3
16000 -1.3 29.7 200 40 20 6.4 3.5 | -2.0 28.4 230 61 31 5.7 3.1
15500 -0.4 31.3 200 38 20 5.8 3.2 | -1.2 29.8 235 61 31 5.7 3.1
15000 0.3 32.5 195 37 19 4.8 2.6 | -0.3 31.5 235 59 30 6.7 3.7
14500 1.0 33.8 195 36 18 4.9 2.7 | 0.6 33.1 235 56 29 7.0 3.8
14000 1.8 35.2 195 34 18 7.0 3.8 | 1.5 34.7 240 52 27 7.4 4.0
13500 2.8 37.0 190 33 17 6.8 3.7 | 2.5 36.5 240 48 25 7.4 4.1
13000 3.8 38.8 190 32 17 7.3 4.0 | 3.6 38.5 240 44 23 8.7 4.8
12500 4.9 40.8 185 31 16 7.9 4.3 | 4.6 40.3 245 41 21 6.9 3.8
12000 6.0 42.8 180 29 15 7.0 3.8 | 5.6 42.1 245 36 19 7.4 4.1
11750 6.5 43.7 180 28 15 7.5 4.1 | 6.2 43.2 240 35 18 7.7 4.2
11500 7.1 44.8 180 28 14 9.4 5.1 | 6.7 44.1 240 35 18 7.7 4.2
11250 7.8 46.0 175 28 14 9.7 5.3 | 7.2 45.0 240 34 17 7.9 4.3
11000 8.5 47.3 175 27 14 8.6 4.7 | 7.8 46.0 235 33 17 7.7 4.2
10750 9.1 48.4 175 27 14 7.8 4.3 | 8.3 46.9 235 34 17 7.3 4.0
10500 9.7 49.5 175 27 14 9.1 5.0 | 8.9 48.0 230 34 17 8.1 4.4
10250 10.4 50.7 175 27 14 10.9 6.0 | 9.5 49.1 230 34 17 10.4 5.7
10000 11.2 52.2 175 26 14 9.8 5.4 | 10.3 50.5 225 33 17 9.1 5.0
9750 11.9 53.4 175 26 14 9.0 4.9 | 10.8 51.4 225 32 17 7.4 4.0
9500 12.6 54.7 175 26 14 8.6 4.7 | 11.3 52.3 225 31 16 7.1 3.9
9250 13.2 55.8 175 26 13 10.9 6.0 | 11.8 53.2 225 30 15 10.1 5.5
9000 14.1 57.4 175 26 13 11.7 6.4 | 12.7 54.9 225 28 14 11.0 6.0
8750 14.9 58.8 175 25 13 9.9 5.4 | 13.4 56.1 220 26 14 8.5 4.6
8500 15.7 60.3 175 25 13 10.7 5.9 | 14.0 57.2 220 25 13 9.4 5.1
8250 16.4 61.5 175 25 13 9.2 5.0 | 14.7 58.5 220 23 12 8.3 4.5
8000 17.1 62.8 175 24 12 12.3 6.7 | 15.2 59.4 215 21 11 8.5 4.7
7750 18.4 65.1 175 21 11 21.4 11.8 | 15.9 60.6 215 17 9 11.5 6.3
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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