Soaring Guidance
Issued by NWS Pueblo, CO
Issued by NWS Pueblo, CO
647
UXUS97 KPUB 301230
SRGPUB
Soaring Forecast
National Weather Service Pueblo, Colorado
0630 MDT Sunday, June 30, 2024
This forecast is for the Air Force Academy for Sunday, June 30, 2024:
If the trigger temperature of 70.6 F/21.5 C is reached...then
Thermal Soaring Index....................... Good
Maximum rate of lift........................ 539 ft/min (2.7 m/s)
Maximum height of thermals.................. 16202 ft MSL (8675 ft AGL)
Forecast maximum temperature................... 81.0 F/27.7 C
Time of trigger temperature.................... 1030 MDT
Time of overdevelopment........................ 1300 MDT
Middle/high clouds during soaring window....... Broken/overcast opaque middle
Surface winds during soaring window............ 20 mph or less
Height of the -3 thermal index................. 13217 ft MSL (5689 ft AGL)
Thermal soaring outlook for Monday 07/01....... Good
Wave Soaring Index............................. Not available
Remarks...
Sunrise/Sunset.................... 05:37:23 / 20:28:53 MDT
Total possible sunshine........... 14 hr 51 min 30 sec (891 min 30 sec)
Altitude of sun at 13:03:08 MDT... 74.11 degrees
Upper air data from numerical model forecast valid on 06/30/2024 at 0600 MDT
Freezing level.................. 16738 ft MSL (9211 ft AGL)
Convective condensation level... 12788 ft MSL (5261 ft AGL)
Lifted condensation level....... 14376 ft MSL (6849 ft AGL)
Lifted index.................... -5.2
K index......................... +28.6
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 -64.4 -83.9 270 26 13 3.4 1.8 M M M M M
45000 -58.1 -72.6 255 39 20 5.3 2.9 M M M M M
40000 -49.3 -56.7 230 58 30 8.3 4.6 M M M M M
38000 -44.2 -47.6 230 54 28 8.4 4.6 M M M M M
36000 -39.2 -38.6 225 51 26 8.1 4.4 M M M M M
34000 -33.8 -28.8 230 46 24 8.0 4.4 M M M M M
32000 -29.1 -20.4 235 42 22 7.8 4.3 47.1 116.7 15.1 M M
30000 -25.2 -13.4 245 38 20 6.6 3.6 44.4 111.9 13.3 M M
29000 -23.2 -9.8 250 36 19 6.6 3.6 43.3 110.0 12.6 M M
28000 -21.3 -6.3 250 34 18 6.2 3.4 42.1 107.8 11.7 M M
27000 -19.5 -3.1 250 31 16 6.3 3.4 40.7 105.3 10.7 M M
26000 -17.6 0.3 250 27 14 6.3 3.4 39.4 103.0 9.8 M M
25000 -15.8 3.6 245 24 12 6.2 3.4 38.3 100.9 8.9 M M
24000 -14.0 6.8 245 23 12 6.2 3.4 36.9 98.4 7.8 M M
23000 -12.2 10.0 245 22 11 6.2 3.4 35.6 96.2 6.7 M M
22000 -10.3 13.5 240 20 10 6.5 3.6 34.5 94.1 5.8 M M
21000 -8.5 16.7 245 18 9 6.6 3.6 33.3 92.0 4.7 M M
20000 -6.6 20.1 245 15 8 6.6 3.6 32.3 90.1 3.7 M M
19500 -5.6 21.9 245 14 7 6.6 3.6 31.8 89.2 3.3 M M
19000 -4.7 23.5 245 13 7 6.3 3.5 31.2 88.2 2.8 M M
18500 -3.8 25.2 245 12 6 6.3 3.5 30.6 87.1 2.2 M M
18000 -2.8 27.0 245 11 6 6.7 3.7 30.1 86.2 1.7 M M
17500 -1.3 29.7 240 12 6 6.9 3.8 29.4 84.8 1.1 M M
17000 -0.3 31.5 240 12 6 6.9 3.8 28.9 84.0 0.6 M M
16500 0.7 33.3 240 12 6 7.0 3.8 28.4 83.2 0.2 M M
16000 1.7 35.1 235 13 7 7.0 3.8 28.0 82.4 -0.3 711 3.6
15500 2.7 36.9 235 13 7 7.0 3.8 27.5 81.5 -0.7 666 3.4
15000 3.7 38.7 235 13 7 7.0 3.8 27.1 80.7 -1.2 622 3.2
14500 4.7 40.5 230 14 7 6.9 3.8 26.6 79.9 -1.7 577 2.9
14000 5.7 42.3 230 15 8 7.0 3.8 26.2 79.1 -2.1 533 2.7
13500 6.6 43.9 230 16 8 5.9 3.3 25.7 78.2 -2.7 490 2.5
13000 7.4 45.3 230 18 9 5.9 3.2 25.0 77.0 -3.4 452 2.3
12500 8.2 46.8 225 20 10 5.4 3.0 24.4 76.0 -4.0 413 2.1
12000 8.9 48.0 225 21 11 4.8 2.7 23.7 74.6 -4.9 379 1.9
11750 9.2 48.6 220 22 11 6.0 3.3 23.3 73.9 -5.3 362 1.8
11500 9.6 49.3 220 23 12 5.7 3.1 23.0 73.5 -5.6 341 1.7
11250 9.9 49.8 220 23 12 4.3 2.3 22.6 72.7 -6.1 325 1.6
11000 10.2 50.4 215 23 12 4.7 2.6 22.2 72.0 -6.5 308 1.6
10750 10.5 50.9 215 23 12 4.6 2.5 21.8 71.3 -6.9 292 1.5
10500 10.8 51.4 210 24 12 4.6 2.5 21.4 70.6 -7.4 276 1.4
10250 11.1 52.0 205 24 12 4.9 2.7 21.1 69.9 -7.8 259 1.3
10000 11.5 52.7 200 24 12 5.0 2.7 20.7 69.2 -8.3 242 1.2
9750 11.8 53.2 200 24 12 5.1 2.8 20.3 68.6 -8.7 224 1.1
9500 12.1 53.8 195 24 12 2.6 1.4 19.9 67.9 -9.1 208 1.1
9250 12.2 54.0 190 25 13 1.6 0.9 19.3 66.7 -9.8 198 1.0
9000 12.4 54.3 185 25 13 3.5 1.9 18.7 65.7 -10.3 185 0.9
8750 12.6 54.7 180 24 12 3.5 1.9 18.3 64.9 -10.8 170 0.9
8500 12.8 55.0 180 23 12 2.9 1.6 17.8 64.0 -11.4 157 0.8
8250 13.0 55.4 175 21 11 2.5 1.4 17.2 63.0 -12.0 144 0.7
8000 13.2 55.8 175 20 10 6.5 3.6 16.8 62.2 -12.5 129 0.7
7750 13.9 57.0 175 18 9 9.9 5.4 16.7 62.1 -12.6 103 0.5
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 * * * * * *
06/30/2024 at 0900 MDT | 06/30/2024 at 1200 MDT
|
CAPE... +434.2 LI... -2.1 | CAPE... +1244.1 LI... -4.2
CINH... -33.7 K Index... +25.2 | CINH... -13.2 K Index... +25.2
|
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 -63.9 -83.0 265 21 11 3.8 2.1 | -64.7 -84.5 250 18 9 2.9 1.6
45000 -57.6 -71.7 260 34 17 4.8 2.6 | -58.2 -72.8 250 31 16 6.1 3.4
40000 -49.2 -56.6 240 48 25 8.3 4.5 | -48.4 -55.1 245 43 22 7.9 4.4
38000 -44.2 -47.6 230 47 24 8.3 4.6 | -43.6 -46.5 240 43 22 7.9 4.4
36000 -38.7 -37.7 225 46 24 8.0 4.4 | -38.3 -36.9 235 43 22 7.7 4.2
34000 -33.9 -29.0 225 45 23 8.0 4.4 | -33.6 -28.5 235 43 22 7.7 4.2
32000 -29.1 -20.4 230 44 22 8.1 4.4 | -29.0 -20.2 235 44 23 7.8 4.3
30000 -24.9 -12.8 235 41 21 7.0 3.8 | -25.0 -13.0 240 42 21 6.6 3.6
29000 -22.8 -9.0 240 40 21 6.9 3.8 | -23.1 -9.6 240 41 21 6.6 3.6
28000 -20.8 -5.4 245 39 20 6.2 3.4 | -21.1 -6.0 245 40 20 6.4 3.5
27000 -19.0 -2.2 240 35 18 6.3 3.5 | -19.2 -2.6 240 38 20 6.4 3.5
26000 -17.2 1.0 240 32 17 6.4 3.5 | -17.3 0.9 240 37 19 6.4 3.5
25000 -15.3 4.5 240 29 15 6.1 3.3 | -15.4 4.3 240 36 18 6.4 3.5
24000 -13.6 7.5 240 28 14 5.9 3.2 | -13.6 7.5 240 35 18 6.4 3.5
23000 -11.9 10.6 245 26 13 5.9 3.3 | -11.7 10.9 240 34 17 6.4 3.5
22000 -10.1 13.8 245 24 13 6.5 3.6 | -9.8 14.4 240 32 17 6.4 3.5
21000 -8.1 17.4 250 22 11 6.8 3.7 | -7.9 17.8 245 29 15 6.5 3.6
20000 -5.7 21.7 260 20 10 6.8 3.7 | -6.1 21.0 245 25 13 6.5 3.6
19500 -4.7 23.5 260 19 10 6.8 3.7 | -5.1 22.8 250 24 12 6.4 3.5
19000 -3.7 25.3 260 16 8 6.8 3.7 | -3.8 25.2 250 22 11 6.2 3.4
18500 -2.8 27.0 260 14 7 6.8 3.7 | -2.9 26.8 255 21 11 6.3 3.5
18000 -1.8 28.8 255 12 6 6.2 3.4 | -1.9 28.6 250 20 10 7.1 3.9
17500 -1.0 30.2 255 11 5 6.2 3.4 | -0.9 30.4 250 19 10 7.0 3.9
17000 -0.1 31.8 250 9 5 6.4 3.5 | 0.1 32.2 250 17 9 7.0 3.8
16500 0.9 33.6 250 9 5 6.5 3.6 | 1.1 34.0 255 16 8 7.0 3.8
16000 1.8 35.2 250 9 4 6.6 3.6 | 2.1 35.8 255 15 8 7.1 3.9
15500 2.8 37.0 250 9 5 6.9 3.8 | 3.2 37.8 260 15 7 7.4 4.1
15000 3.8 38.8 250 10 5 6.9 3.8 | 4.2 39.6 265 14 7 7.4 4.0
14500 4.8 40.6 245 11 6 6.7 3.7 | 5.4 41.7 265 14 7 8.0 4.4
14000 5.7 42.3 245 12 6 6.8 3.7 | 6.5 43.7 270 14 7 8.0 4.4
13500 6.7 44.1 245 13 7 7.0 3.9 | 7.7 45.9 270 14 7 8.4 4.6
13000 7.7 45.9 245 14 7 7.0 3.8 | 8.9 48.0 270 14 7 8.0 4.4
12500 8.6 47.5 245 16 8 5.9 3.3 | 9.9 49.8 270 15 8 7.3 4.0
12000 9.5 49.1 245 16 8 6.5 3.6 | 11.0 51.8 270 15 8 8.0 4.4
11750 9.9 49.8 245 17 9 5.9 3.2 | 11.6 52.9 270 16 8 7.8 4.3
11500 10.3 50.5 240 18 9 5.8 3.2 | 12.2 54.0 265 16 8 7.8 4.3
11250 10.8 51.4 240 19 10 6.4 3.5 | 12.7 54.9 265 15 8 8.0 4.4
11000 11.2 52.2 240 19 10 6.2 3.4 | 13.2 55.8 260 15 8 8.0 4.4
10750 11.6 52.9 240 20 10 6.3 3.4 | 13.7 56.7 260 14 7 8.2 4.5
10500 12.1 53.8 240 20 10 6.4 3.5 | 14.2 57.6 255 14 7 6.3 3.5
10250 12.5 54.5 240 21 11 5.7 3.1 | 14.6 58.3 250 13 7 7.6 4.2
10000 12.8 55.0 240 20 11 4.8 2.6 | 15.3 59.5 245 12 6 9.8 5.4
9750 13.1 55.6 235 20 10 5.8 3.2 | 16.0 60.8 245 12 6 10.3 5.7
9500 13.4 56.1 235 20 10 1.7 0.9 | 16.6 61.9 240 11 6 3.5 1.9
9250 13.3 55.9 230 20 10 1.6 0.9 | 16.6 61.9 220 10 5 4.0 2.2
9000 13.7 56.7 225 19 10 7.0 3.8 | 17.3 63.1 215 10 5 12.3 6.7
8750 14.1 57.4 220 19 10 7.0 3.8 | 18.1 64.6 210 10 5 11.5 6.3
8500 14.5 58.1 215 18 9 3.8 2.1 | 18.9 66.0 210 10 5 8.8 4.8
8250 14.6 58.3 205 16 8 2.0 1.1 | 19.4 66.9 195 10 5 7.5 4.1
8000 14.8 58.6 195 15 8 6.3 3.5 | 20.0 68.0 185 10 5 8.8 4.8
7750 15.5 59.9 195 14 7 13.4 7.4 | 20.8 69.4 190 10 5 17.8 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
06/30/2024 at 1500 MDT | 06/30/2024 at 1800 MDT
|
CAPE... +1594.3 LI... -5.1 | CAPE... +2056.2 LI... -5.9
CINH... -9.9 K Index... +32.4 | CINH... -12.8 K Index... +33.2
|
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 -65.1 -85.2 225 22 11 2.5 1.4 | -65.5 -85.9 225 29 15 2.6 1.4
45000 -58.7 -73.7 240 33 17 6.6 3.6 | -58.9 -74.0 235 37 19 6.8 3.7
40000 -48.3 -54.9 240 44 23 8.1 4.4 | -48.3 -54.9 235 45 23 8.0 4.4
38000 -43.5 -46.3 240 45 23 8.1 4.4 | -43.5 -46.3 235 47 24 8.0 4.4
36000 -38.1 -36.6 235 45 23 7.5 4.1 | -38.2 -36.8 235 48 25 7.5 4.1
34000 -33.6 -28.5 235 46 23 7.5 4.1 | -33.7 -28.7 235 47 24 7.5 4.1
32000 -29.1 -20.4 240 46 24 7.2 3.9 | -29.2 -20.6 235 45 23 7.2 3.9
30000 -25.3 -13.5 240 42 22 6.5 3.6 | -25.2 -13.4 240 42 21 6.7 3.7
29000 -23.4 -10.1 240 41 21 6.5 3.6 | -23.2 -9.8 240 40 21 6.7 3.7
28000 -21.4 -6.5 240 40 20 6.4 3.5 | -21.2 -6.2 245 38 20 6.6 3.6
27000 -19.5 -3.1 240 40 21 6.4 3.5 | -19.3 -2.7 245 37 19 6.7 3.7
26000 -17.6 0.3 240 40 21 6.4 3.5 | -17.3 0.9 245 36 19 6.7 3.7
25000 -15.7 3.7 245 40 21 6.9 3.8 | -15.3 4.5 245 35 18 6.9 3.8
24000 -13.6 7.5 245 37 19 7.1 3.9 | -13.3 8.1 240 35 18 7.0 3.8
23000 -11.6 11.1 245 34 17 7.1 3.9 | -11.3 11.7 240 34 17 7.1 3.9
22000 -9.5 14.9 245 31 16 6.2 3.4 | -9.3 15.3 240 33 17 6.1 3.3
21000 -7.8 18.0 250 29 15 6.0 3.3 | -7.6 18.3 240 31 16 5.8 3.2
20000 -6.0 21.2 250 28 14 6.0 3.3 | -5.9 21.4 240 30 15 5.9 3.2
19500 -5.1 22.8 255 28 14 6.0 3.3 | -5.1 22.8 240 29 15 6.0 3.3
19000 -3.9 25.0 255 27 14 6.2 3.4 | -3.8 25.2 240 28 15 6.3 3.5
18500 -3.0 26.6 255 27 14 6.2 3.4 | -2.8 27.0 240 28 14 6.4 3.5
18000 -2.1 28.2 255 26 13 6.2 3.4 | -1.9 28.6 240 27 14 6.9 3.8
17500 -1.2 29.8 260 25 13 6.2 3.4 | -0.9 30.4 240 26 14 6.9 3.8
17000 -0.3 31.5 260 24 13 7.2 3.9 | 0.1 32.2 240 25 13 7.7 4.2
16500 0.7 33.3 260 23 12 7.4 4.1 | 1.2 34.2 240 24 12 7.9 4.3
16000 1.7 35.1 260 21 11 7.8 4.3 | 2.3 36.1 235 23 12 8.0 4.4
15500 2.9 37.2 260 19 10 8.6 4.7 | 3.5 38.3 235 22 11 8.2 4.5
15000 4.2 39.6 255 18 9 8.6 4.7 | 4.6 40.3 235 21 11 8.2 4.5
14500 5.5 41.9 255 16 8 9.4 5.2 | 5.8 42.4 235 20 10 8.8 4.8
14000 6.8 44.2 255 15 8 9.4 5.1 | 7.1 44.8 230 19 10 8.7 4.8
13500 8.2 46.8 250 14 7 9.5 5.2 | 8.3 46.9 230 18 9 9.0 5.0
13000 9.5 49.1 245 13 7 9.3 5.1 | 9.6 49.3 230 16 8 8.9 4.9
12500 10.9 51.6 245 13 7 8.6 4.7 | 10.8 51.4 230 15 8 7.7 4.2
12000 12.1 53.8 235 12 6 8.4 4.6 | 11.9 53.4 225 14 7 7.5 4.1
11750 12.7 54.9 230 12 6 9.4 5.1 | 12.4 54.3 225 13 7 7.6 4.2
11500 13.4 56.1 235 12 6 9.2 5.0 | 13.0 55.4 225 13 7 7.8 4.3
11250 14.0 57.2 230 12 6 8.1 4.5 | 13.5 56.3 220 13 7 7.8 4.3
11000 14.6 58.3 225 11 6 8.4 4.6 | 14.1 57.4 215 12 6 7.8 4.3
10750 15.2 59.4 215 11 6 8.5 4.7 | 14.7 58.5 210 11 6 8.0 4.4
10500 15.7 60.3 210 11 6 6.6 3.6 | 15.2 59.4 205 11 6 7.2 3.9
10250 16.2 61.2 200 11 6 7.9 4.3 | 15.7 60.3 205 9 5 7.7 4.2
10000 16.9 62.4 200 11 6 10.2 5.6 | 16.3 61.3 200 9 5 8.7 4.8
9750 17.6 63.7 195 11 6 10.4 5.7 | 16.9 62.4 195 9 4 9.0 4.9
9500 18.3 64.9 195 11 6 6.4 3.5 | 17.5 63.5 190 9 4 6.9 3.8
9250 18.6 65.5 185 12 6 7.2 4.0 | 18.0 64.4 195 6 3 7.5 4.1
9000 19.4 66.9 185 11 6 12.3 6.8 | 18.7 65.7 190 7 3 10.6 5.8
8750 20.3 68.5 185 11 6 11.8 6.5 | 19.4 66.9 185 7 4 10.4 5.7
8500 21.1 70.0 185 11 6 8.9 4.9 | 20.1 68.2 180 7 4 9.3 5.1
8250 21.6 70.9 180 11 6 7.1 3.9 | 20.7 69.3 185 6 3 8.4 4.6
8000 22.2 72.0 180 11 6 9.6 5.3 | 21.3 70.3 185 6 3 9.3 5.1
7750 23.1 73.6 180 11 6 15.7 8.6 | 22.1 71.8 180 6 3 11.6 6.4
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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