Soaring Guidance
Issued by NWS Pueblo, CO
Issued by NWS Pueblo, CO
622
UXUS97 KPUB 141457
SRGPUB
Soaring Forecast
National Weather Service Pueblo, Colorado
0857 MDT Friday, June 14, 2024
This forecast is for the Air Force Academy for Friday, June 14, 2024:
If the trigger temperature of 73.9 F/23.3 C is reached...then
Thermal Soaring Index....................... Poor
Maximum rate of lift........................ 492 ft/min (2.5 m/s)
Maximum height of thermals.................. 15448 ft MSL (7833 ft AGL)
Forecast maximum temperature................... 81.0 F/27.7 C
Time of trigger temperature.................... 0930 MDT
Time of overdevelopment........................ 1100 MDT
Middle/high clouds during soaring window....... Broken/overcast thin middle
Surface winds during soaring window............ More than 30 mph
Height of the -3 thermal index................. 12056 ft MSL (4441 ft AGL)
Thermal soaring outlook for Saturday 06/15..... Good
Wave Soaring Index............................. Not available
Remarks...
Sunrise/Sunset.................... 05:33:07 / 20:26:23 MDT
Total possible sunshine........... 14 hr 53 min 16 sec (893 min 16 sec)
Altitude of sun at 12:59:45 MDT... 74.33 degrees
Upper air data from numerical model forecast valid on 06/14/2024 at 0600 MDT
Freezing level.................. 16808 ft MSL (9193 ft AGL)
Convective condensation level... 16127 ft MSL (8512 ft AGL)
Lifted condensation level....... 16152 ft MSL (8537 ft AGL)
Lifted index.................... -6.1
K index......................... +20.1
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 -61.4 -78.5 255 35 18 2.5 1.3 M M M M M
45000 -56.9 -70.4 245 43 22 4.1 2.2 M M M M M
40000 -51.0 -59.8 230 46 23 3.0 1.6 M M M M M
38000 -49.2 -56.6 230 32 17 2.9 1.6 M M M M M
36000 -47.4 -53.3 230 19 10 2.6 1.4 M M M M M
34000 -42.2 -44.0 230 16 8 8.7 4.8 M M M M M
32000 -37.0 -34.6 235 16 8 9.1 5.0 M M M M M
30000 -31.8 -25.2 230 19 10 8.7 4.8 36.2 97.2 7.0 M M
29000 -29.2 -20.6 225 20 10 8.7 4.8 35.9 96.6 6.8 M M
28000 -26.7 -16.1 225 22 11 7.8 4.3 35.6 96.1 6.6 M M
27000 -24.4 -11.9 225 21 11 7.6 4.2 34.7 94.4 5.9 M M
26000 -22.1 -7.8 225 20 11 7.6 4.2 33.9 93.0 5.3 M M
25000 -19.9 -3.8 225 20 10 7.4 4.1 33.2 91.8 4.8 M M
24000 -17.9 -0.2 225 21 11 6.7 3.6 32.1 89.7 3.9 M M
23000 -15.9 3.4 220 23 12 6.7 3.7 30.9 87.7 2.9 M M
22000 -14.0 6.8 220 25 13 7.2 4.0 30.0 85.9 2.1 M M
21000 -10.9 12.4 215 22 11 8.5 4.7 29.3 84.7 1.4 M M
20000 -8.5 16.7 215 19 10 8.5 4.7 28.9 84.0 1.0 M M
19500 -7.2 19.0 210 18 9 8.9 4.9 28.7 83.7 0.8 M M
19000 -5.8 21.6 210 17 9 9.5 5.2 28.6 83.6 0.8 M M
18500 -4.4 24.1 210 16 8 9.6 5.3 28.6 83.5 0.8 M M
18000 -3.0 26.6 205 16 8 8.7 4.8 28.5 83.4 0.7 M M
17500 -1.7 28.9 205 15 8 8.7 4.8 28.3 83.0 0.6 M M
17000 -0.4 31.3 205 14 7 8.7 4.8 28.2 82.7 0.4 M M
16500 0.9 33.6 200 14 7 8.8 4.8 28.0 82.4 0.3 M M
16000 2.2 36.0 200 13 7 8.8 4.8 27.9 82.2 0.1 M M
15500 3.6 38.5 195 12 6 9.0 4.9 27.7 81.9 0.0 M M
15000 4.9 40.8 190 11 6 9.0 4.9 27.6 81.7 -0.1 641 3.3
14500 6.2 43.2 185 11 5 8.2 4.5 27.4 81.4 -0.3 588 3.0
14000 7.3 45.1 175 10 5 7.9 4.3 27.1 80.9 -0.6 539 2.7
13500 8.4 47.1 165 10 5 7.4 4.1 26.9 80.4 -1.0 491 2.5
13000 9.4 48.9 160 10 5 6.6 3.6 26.4 79.5 -1.5 448 2.3
12500 10.2 50.4 160 10 5 5.5 3.0 25.8 78.5 -2.2 409 2.1
12000 10.8 51.4 165 8 4 4.9 2.7 25.1 77.1 -3.0 376 1.9
11750 11.1 52.0 170 8 4 4.9 2.7 24.7 76.4 -3.5 360 1.8
11500 11.4 52.5 170 7 4 5.5 3.0 24.3 75.8 -3.9 344 1.7
11250 11.8 53.2 180 7 3 7.3 4.0 24.1 75.3 -4.2 323 1.6
11000 12.4 54.3 190 6 3 8.0 4.4 23.9 75.0 -4.4 299 1.5
10750 12.9 55.2 200 5 3 8.5 4.7 23.8 74.8 -4.6 275 1.4
10500 13.5 56.3 215 5 2 5.6 3.1 23.6 74.5 -4.8 251 1.3
10250 13.7 56.7 225 5 2 3.1 1.7 23.1 73.7 -5.3 237 1.2
10000 14.0 57.2 235 5 2 4.0 2.2 22.7 72.8 -5.8 222 1.1
9750 14.2 57.6 245 5 3 4.2 2.3 22.2 72.0 -6.3 207 1.0
9500 14.5 58.1 255 6 3 2.4 1.3 21.8 71.2 -6.7 191 1.0
9250 14.4 57.9 250 6 3 -3.9 -2.1 21.0 69.8 -7.6 187 0.9
9000 13.9 57.0 235 5 3 -5.3 -2.9 19.8 67.7 -8.8 194 1.0
8750 13.5 56.3 225 5 3 -4.0 -2.2 18.8 65.8 -10.0 199 1.0
8500 13.1 55.6 215 5 3 -3.4 -1.9 17.7 63.9 -11.1 204 1.0
8250 12.9 55.2 200 5 2 -1.0 -0.5 16.8 62.3 -12.1 203 1.0
8000 12.8 55.0 185 3 2 -3.1 -1.7 16.0 60.8 -12.9 198 1.0
7750 12.4 54.3 210 1 1 -8.2 -4.5 14.8 58.7 -14.1 202 1.0
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 * * * * * *
06/14/2024 at 0900 MDT | 06/14/2024 at 1200 MDT
|
CAPE... +1141.0 LI... -2.4 | CAPE... +2231.9 LI... -5.7
CINH... -179.8 K Index... +22.2 | CINH... -18.4 K Index... +26.5
|
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 -59.9 -75.8 245 33 17 2.7 1.5 | -59.1 -74.4 250 30 16 3.0 1.6
45000 -55.8 -68.4 240 48 25 3.0 1.6 | -54.7 -66.5 245 44 23 2.9 1.6
40000 -51.4 -60.5 235 49 25 2.5 1.4 | -50.5 -58.9 240 44 23 1.7 0.9
38000 -49.9 -57.8 235 35 18 2.5 1.4 | -49.5 -57.1 230 31 16 1.7 1.0
36000 -48.2 -54.8 230 20 10 3.1 1.7 | -48.3 -54.9 205 19 10 1.9 1.0
34000 -42.9 -45.2 230 16 8 9.3 5.1 | -43.1 -45.6 200 19 10 9.3 5.1
32000 -37.3 -35.1 230 14 7 9.3 5.1 | -37.5 -35.5 195 20 10 9.3 5.1
30000 -32.2 -26.0 230 17 9 8.5 4.6 | -32.5 -26.5 205 22 12 8.4 4.6
29000 -29.7 -21.5 235 19 10 8.5 4.6 | -30.0 -22.0 210 24 12 8.4 4.6
28000 -27.2 -17.0 235 20 10 7.7 4.2 | -27.5 -17.5 215 26 13 7.6 4.2
27000 -25.0 -13.0 230 21 11 7.4 4.1 | -25.4 -13.7 215 28 14 7.3 4.0
26000 -22.8 -9.0 225 22 11 7.4 4.1 | -23.2 -9.8 210 30 15 7.4 4.0
25000 -20.6 -5.1 220 23 12 7.4 4.1 | -21.0 -5.8 210 32 16 7.4 4.1
24000 -18.6 -1.5 215 25 13 6.9 3.8 | -18.7 -1.7 205 33 17 8.0 4.4
23000 -16.5 2.3 210 27 14 7.0 3.8 | -16.3 2.7 205 34 18 8.0 4.4
22000 -14.5 5.9 210 29 15 7.5 4.1 | -14.0 6.8 200 35 18 8.0 4.4
21000 -11.9 10.6 205 27 14 9.0 5.0 | -11.7 10.9 200 34 17 7.8 4.3
20000 -8.5 16.7 205 24 12 9.1 5.0 | -8.8 16.2 205 32 16 7.8 4.3
19500 -7.2 19.0 205 23 12 9.3 5.1 | -7.7 18.1 205 31 16 8.4 4.6
19000 -5.8 21.6 200 22 12 9.7 5.3 | -6.3 20.7 210 29 15 9.6 5.2
18500 -4.3 24.3 200 22 11 9.7 5.3 | -4.9 23.2 210 27 14 9.6 5.2
18000 -2.9 26.8 200 22 11 9.4 5.1 | -3.5 25.7 215 25 13 9.5 5.2
17500 -1.5 29.3 200 21 11 9.3 5.1 | -2.0 28.4 215 24 12 9.5 5.2
17000 -0.1 31.8 200 21 11 9.2 5.1 | -0.6 30.9 215 23 12 9.6 5.3
16500 1.2 34.2 200 21 11 9.0 4.9 | 0.9 33.6 215 22 11 9.7 5.3
16000 2.6 36.7 200 20 10 9.1 5.0 | 2.3 36.1 215 22 11 9.8 5.4
15500 3.8 38.8 195 19 10 8.1 4.4 | 3.6 38.5 220 22 11 8.2 4.5
15000 5.0 41.0 195 18 9 8.2 4.5 | 4.8 40.6 220 22 11 8.5 4.7
14500 6.2 43.2 190 17 9 7.4 4.0 | 6.0 42.8 220 21 11 7.0 3.8
14000 7.2 45.0 190 16 8 7.1 3.9 | 6.8 44.2 225 19 10 6.6 3.6
13500 8.2 46.8 185 14 7 6.6 3.6 | 7.7 45.9 230 17 9 6.4 3.5
13000 9.0 48.2 190 11 6 5.9 3.2 | 8.5 47.3 235 13 7 6.3 3.5
12500 9.7 49.5 195 8 4 5.3 2.9 | 9.4 48.9 235 11 5 6.6 3.6
12000 10.3 50.5 205 5 3 4.7 2.6 | 10.1 50.2 235 9 4 4.4 2.4
11750 10.6 51.1 215 4 2 5.0 2.7 | 10.5 50.9 235 8 4 6.2 3.4
11500 10.9 51.6 225 3 2 5.6 3.1 | 11.0 51.8 240 7 3 9.4 5.2
11250 11.4 52.5 230 2 1 5.7 3.1 | 11.7 53.1 235 6 3 7.2 4.0
11000 11.8 53.2 230 2 1 5.5 3.0 | 12.1 53.8 235 5 3 5.6 3.1
10750 12.2 54.0 225 1 1 5.6 3.1 | 12.5 54.5 235 5 2 4.5 2.5
10500 12.6 54.7 220 1 0 5.6 3.1 | 12.9 55.2 230 4 2 10.5 5.8
10250 13.0 55.4 250 1 1 5.7 3.1 | 13.8 56.8 220 3 2 11.9 6.5
10000 13.4 56.1 260 2 1 5.4 2.9 | 14.3 57.7 200 4 2 6.4 3.5
9750 13.8 56.8 265 2 1 6.5 3.5 | 14.8 58.6 185 4 2 8.7 4.8
9500 14.2 57.6 265 3 1 2.5 1.4 | 15.3 59.5 175 5 2 5.4 3.0
9250 14.1 57.4 250 3 2 -1.9 -1.0 | 15.6 60.1 165 5 3 6.3 3.5
9000 14.0 57.2 220 4 2 2.2 1.2 | 16.2 61.2 160 6 3 11.1 6.1
8750 14.2 57.6 200 5 3 4.3 2.3 | 17.1 62.8 160 6 3 11.3 6.2
8500 14.4 57.9 190 7 3 4.4 2.4 | 17.9 64.2 155 7 3 10.7 5.9
8250 14.7 58.5 185 7 4 7.1 3.9 | 18.7 65.7 150 7 4 10.7 5.9
8000 15.5 59.9 180 7 4 14.8 8.1 | 19.7 67.5 150 7 4 17.9 9.8
7750 16.9 62.4 175 7 4 23.7 13.0 | 21.4 70.5 150 7 4 27.8 15.3
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
06/14/2024 at 1500 MDT | 06/14/2024 at 1800 MDT
|
CAPE... +522.4 LI... -2.8 | CAPE... +287.1 LI... -1.9
CINH... -38.9 K Index... +30.1 | CINH... -65.5 K Index... +10.8
|
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 -59.5 -75.1 245 31 16 2.3 1.2 | -60.6 -77.1 245 27 14 2.9 1.6
45000 -56.0 -68.8 250 40 21 2.5 1.4 | -56.5 -69.7 230 27 14 2.2 1.2
40000 -51.9 -61.4 265 37 19 5.7 3.1 | -52.3 -62.1 175 19 10 7.4 4.1
38000 -48.1 -54.6 265 29 15 5.7 3.1 | -47.8 -54.0 170 32 16 7.6 4.2
36000 -44.6 -48.3 265 22 11 5.7 3.1 | -43.2 -45.8 170 44 23 7.6 4.2
34000 -40.5 -40.9 240 19 10 7.1 3.9 | -38.1 -36.6 175 40 21 7.7 4.2
32000 -36.2 -33.2 210 21 11 6.9 3.8 | -33.5 -28.3 185 34 18 7.5 4.1
30000 -31.1 -24.0 200 22 11 8.7 4.8 | -29.3 -20.7 190 32 16 6.9 3.8
29000 -28.5 -19.3 195 22 11 8.7 4.8 | -27.3 -17.1 195 31 16 6.9 3.8
28000 -25.9 -14.6 190 23 12 8.3 4.6 | -25.2 -13.4 200 31 16 6.5 3.5
27000 -23.6 -10.5 195 24 12 8.0 4.4 | -23.4 -10.1 205 32 16 6.1 3.3
26000 -21.3 -6.3 200 26 13 8.0 4.4 | -21.6 -6.9 210 33 17 6.1 3.3
25000 -18.9 -2.0 205 27 14 8.3 4.6 | -19.8 -3.6 210 34 18 5.9 3.2
24000 -16.9 1.6 205 29 15 6.4 3.5 | -17.7 0.1 215 36 19 7.5 4.1
23000 -14.6 5.7 210 31 16 6.4 3.5 | -15.5 4.1 225 38 20 7.5 4.1
22000 -12.8 9.0 210 33 17 6.7 3.7 | -13.3 8.1 225 40 21 7.6 4.1
21000 -10.7 12.7 210 31 16 6.9 3.8 | -11.2 11.8 235 38 20 6.8 3.7
20000 -8.7 16.3 210 30 15 6.9 3.8 | -9.2 15.4 240 36 18 6.8 3.7
19500 -7.7 18.1 205 29 15 6.9 3.8 | -8.1 17.4 245 35 18 6.7 3.7
19000 -6.7 19.9 205 28 14 7.2 3.9 | -7.0 19.4 250 34 18 8.3 4.6
18500 -5.7 21.7 200 26 13 7.1 3.9 | -4.9 23.2 255 33 17 9.0 4.9
18000 -4.6 23.7 200 25 13 7.2 4.0 | -3.5 25.7 255 31 16 8.9 4.9
17500 -3.6 25.5 200 24 12 7.3 4.0 | -2.3 27.9 255 26 13 8.8 4.8
17000 -2.6 27.3 200 23 12 7.3 4.0 | -1.0 30.2 250 21 11 8.7 4.8
16500 -1.6 29.1 200 22 11 6.8 3.7 | 0.1 32.2 250 20 10 6.3 3.5
16000 -0.6 30.9 205 22 12 6.9 3.8 | 1.0 33.8 250 20 10 6.6 3.6
15500 0.3 32.5 210 23 12 7.1 3.9 | 1.9 35.4 250 21 11 5.5 3.0
15000 1.3 34.3 215 23 12 7.1 3.9 | 2.6 36.7 245 21 11 5.5 3.0
14500 2.3 36.1 215 24 12 7.4 4.1 | 3.3 37.9 245 22 11 6.5 3.6
14000 3.4 38.1 220 25 13 7.7 4.2 | 4.3 39.7 245 22 11 7.5 4.1
13500 4.5 40.1 220 26 13 7.9 4.3 | 5.3 41.5 245 22 12 7.8 4.3
13000 5.7 42.3 225 26 13 8.5 4.7 | 6.5 43.7 250 22 11 8.4 4.6
12500 6.7 44.1 225 26 13 5.9 3.2 | 7.7 45.9 250 19 10 8.8 4.8
12000 7.9 46.2 230 26 13 8.5 4.7 | 8.8 47.8 250 17 9 6.4 3.5
11750 8.5 47.3 230 26 13 7.6 4.2 | 9.3 48.7 250 16 8 7.6 4.2
11500 8.9 48.0 235 26 14 3.6 2.0 | 10.0 50.0 250 16 8 11.2 6.1
11250 9.1 48.4 235 27 14 3.5 1.9 | 10.8 51.4 250 15 8 9.1 5.0
11000 9.5 49.1 240 27 14 5.5 3.0 | 11.3 52.3 255 15 8 6.2 3.4
10750 9.9 49.8 245 28 14 5.8 3.2 | 11.7 53.1 255 14 7 5.9 3.2
10500 10.3 50.5 245 29 15 2.4 1.3 | 12.2 54.0 255 14 7 9.9 5.4
10250 10.4 50.7 250 30 16 2.6 1.4 | 13.1 55.6 260 13 7 9.9 5.4
10000 10.7 51.3 250 31 16 6.4 3.5 | 13.5 56.3 265 12 6 5.4 2.9
9750 11.1 52.0 255 31 16 5.5 3.0 | 14.0 57.2 270 11 6 6.9 3.8
9500 11.5 52.7 255 32 16 5.5 3.0 | 14.4 57.9 275 10 5 5.3 2.9
9250 12.0 53.6 255 32 16 9.3 5.1 | 14.7 58.5 285 10 5 3.9 2.2
9000 12.8 55.0 255 31 16 11.1 6.1 | 15.0 59.0 295 10 5 7.1 3.9
8750 13.5 56.3 255 30 16 9.3 5.1 | 15.7 60.3 305 9 5 9.4 5.1
8500 14.2 57.6 255 30 15 9.8 5.4 | 16.3 61.3 320 9 5 8.6 4.7
8250 15.9 60.6 255 28 14 14.7 8.1 | 16.9 62.4 330 9 5 8.0 4.4
8000 17.0 62.6 250 23 12 16.9 9.3 | 17.5 63.5 335 9 4 11.3 6.2
7750 18.2 64.8 250 19 10 14.1 7.7 | 18.6 65.5 340 8 4 17.9 9.8
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
________________________________________________________________________________
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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