Soaring Guidance
Issued by NWS Pueblo, CO
Issued by NWS Pueblo, CO
954
UXUS97 KPUB 171214
SRGPUB
Soaring Forecast
National Weather Service Pueblo, Colorado
0614 MDT Monday, June 17, 2024
This forecast is for the Air Force Academy for Monday, June 17, 2024:
If the trigger temperature of 76.4 F/24.7 C is reached...then
Thermal Soaring Index....................... Good
Maximum rate of lift........................ 2004 ft/min (10.2 m/s)
Maximum height of thermals.................. 27261 ft MSL (19647 ft AGL)
Forecast maximum temperature................... 91.0 F/33.2 C
Time of trigger temperature.................... 0915 MDT
Time of overdevelopment........................ None
Middle/high clouds during soaring window....... None
Surface winds during soaring window............ Between 20 mph and 30 mph
Height of the -3 thermal index................. 23667 ft MSL (16053 ft AGL)
Thermal soaring outlook for Tuesday 06/18...... Good
Wave Soaring Index............................. Not available
Remarks...
Sunrise/Sunset.................... 05:33:22 / 20:27:25 MDT
Total possible sunshine........... 14 hr 54 min 3 sec (894 min 3 sec)
Altitude of sun at 13:00:24 MDT... 74.43 degrees
Upper air data from numerical model forecast valid on 06/17/2024 at 0600 MDT
Freezing level.................. 16111 ft MSL (8497 ft AGL)
Convective condensation level... 21895 ft MSL (14281 ft AGL)
Lifted condensation level....... 24123 ft MSL (16508 ft AGL)
Lifted index.................... -2.9
K index......................... +15.5
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 -58.5 -73.3 240 46 24 3.7 2.0 M M M M M
45000 -54.3 -65.7 240 55 28 -0.5 -0.3 M M M M M
40000 -54.8 -66.6 230 39 20 5.4 2.9 M M M M M
38000 -50.8 -59.4 235 34 17 6.7 3.7 M M M M M
36000 -46.8 -52.2 245 29 15 6.7 3.7 M M M M M
34000 -41.9 -43.4 250 26 13 7.5 4.1 M M M M M
32000 -37.4 -35.3 250 24 12 7.5 4.1 M M M M M
30000 -32.9 -27.2 245 23 12 7.5 4.1 35.1 95.2 1.8 M M
29000 -30.6 -23.1 240 24 12 7.5 4.1 34.2 93.6 1.1 M M
28000 -28.4 -19.1 235 24 12 7.5 4.1 33.5 92.3 0.6 M M
27000 -26.2 -15.2 235 24 12 7.2 4.0 32.5 90.5 -0.2 1980 10.1
26000 -24.1 -11.4 230 24 13 7.2 4.0 31.5 88.7 -1.0 1886 9.6
25000 -21.9 -7.4 230 25 13 7.2 3.9 30.7 87.2 -1.7 1792 9.1
24000 -19.8 -3.6 225 25 13 6.8 3.7 29.7 85.4 -2.6 1700 8.6
23000 -17.8 -0.0 225 27 14 6.9 3.8 28.6 83.5 -3.6 1610 8.2
22000 -15.8 3.6 225 28 14 6.9 3.8 27.6 81.8 -4.5 1520 7.7
21000 -13.6 7.5 220 31 16 8.3 4.6 26.9 80.5 -5.2 1423 7.2
20000 -10.5 13.1 220 37 19 8.6 4.7 26.3 79.4 -6.0 1296 6.6
19500 -9.3 15.3 215 39 20 8.7 4.8 26.2 79.1 -6.2 1245 6.3
19000 -8.1 17.4 215 40 21 9.4 5.1 26.1 78.9 -6.5 1193 6.1
18500 -6.7 19.9 215 39 20 9.5 5.2 26.0 78.8 -6.5 1136 5.8
18000 -5.3 22.5 215 37 19 9.5 5.2 26.0 78.8 -6.6 1079 5.5
17500 -3.8 25.2 220 35 18 9.6 5.3 26.0 78.7 -6.7 1021 5.2
17000 -2.4 27.7 220 34 17 9.7 5.3 25.9 78.7 -6.7 963 4.9
16500 -1.0 30.2 225 32 17 9.1 5.0 25.9 78.6 -6.8 906 4.6
16000 0.4 32.7 225 30 16 8.9 4.9 25.8 78.4 -6.9 849 4.3
15500 1.8 35.2 225 28 14 9.0 5.0 25.6 78.2 -7.0 793 4.0
15000 3.2 37.8 225 25 13 9.2 5.0 25.5 78.0 -7.1 737 3.7
14500 4.6 40.3 225 23 12 9.2 5.0 25.4 77.8 -7.2 680 3.5
14000 6.0 42.8 225 20 11 9.2 5.0 25.4 77.7 -7.3 624 3.2
13500 7.3 45.1 230 19 10 8.3 4.5 25.3 77.5 -7.4 568 2.9
13000 9.1 48.4 230 18 9 12.3 6.7 25.7 78.2 -7.1 499 2.5
12500 10.4 50.7 235 16 8 8.4 4.6 25.4 77.7 -7.4 448 2.3
12000 11.6 52.9 235 15 7 9.2 5.0 25.2 77.3 -7.7 396 2.0
11750 12.3 54.1 235 14 7 9.3 5.1 25.2 77.3 -7.7 367 1.9
11500 13.0 55.4 235 14 7 8.5 4.7 25.1 77.2 -7.8 341 1.7
11250 13.6 56.5 235 13 7 8.6 4.7 25.0 77.0 -7.9 314 1.6
11000 14.2 57.6 240 13 6 8.5 4.6 24.9 76.8 -8.0 288 1.5
10750 14.8 58.6 240 12 6 8.2 4.5 24.8 76.6 -8.1 262 1.3
10500 15.5 59.9 240 12 6 8.7 4.8 24.7 76.4 -8.3 236 1.2
10250 16.2 61.2 240 12 6 9.9 5.4 24.7 76.4 -8.3 208 1.1
10000 16.9 62.4 245 12 6 8.4 4.6 24.6 76.4 -8.4 179 0.9
9750 17.4 63.3 240 12 6 7.2 4.0 24.5 76.0 -8.6 155 0.8
9500 17.9 64.2 240 12 6 6.3 3.5 24.3 75.7 -8.8 132 0.7
9250 18.5 65.3 240 12 6 10.3 5.7 24.1 75.3 -9.0 109 0.6
9000 19.3 66.7 240 12 6 7.8 4.3 24.2 75.5 -9.0 77 0.4
8750 19.5 67.1 235 11 6 2.1 1.1 23.7 74.6 -9.5 63 0.3
8500 19.6 67.3 230 10 5 0.0 0.0 23.1 73.6 -10.1 52 0.3
8250 19.8 67.6 225 9 5 11.1 6.1 22.5 72.6 -10.8 41 0.2
8000 20.5 68.9 225 9 5 -5.8 -3.2 22.6 72.7 -10.7 11 0.1
7750 17.7 63.9 230 7 4 -66.6 -36.6 19.1 66.4 -14.3 87 0.4
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 * * * * * *
06/17/2024 at 0900 MDT | 06/17/2024 at 1200 MDT
|
CAPE... +12.7 LI... +0.3 | CAPE... 0.0 LI... +1.6
CINH... -11.5 K Index... +9.2 | CINH... 0.0 K Index... -3.8
|
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 -59.4 -74.9 250 39 20 3.5 1.9 | -61.0 -77.8 245 44 23 2.7 1.5
45000 -55.1 -67.2 260 44 23 0.2 0.1 | -57.1 -70.8 255 49 25 1.8 1.0
40000 -54.5 -66.1 270 33 17 6.1 3.3 | -54.0 -65.2 255 44 22 7.2 4.0
38000 -50.4 -58.7 270 31 16 6.7 3.7 | -49.9 -57.8 255 42 22 6.9 3.8
36000 -46.4 -51.5 265 30 15 6.7 3.7 | -45.7 -50.3 250 41 21 6.9 3.8
34000 -41.6 -42.9 260 29 15 7.4 4.0 | -40.7 -41.3 250 40 20 7.6 4.2
32000 -37.1 -34.8 255 29 15 7.4 4.1 | -36.1 -33.0 250 38 20 7.7 4.2
30000 -32.7 -26.9 255 27 14 7.5 4.1 | -31.7 -25.1 250 36 18 7.3 4.0
29000 -30.4 -22.7 250 26 13 7.5 4.1 | -29.6 -21.3 250 34 18 7.3 4.0
28000 -28.2 -18.8 250 25 13 7.5 4.1 | -27.4 -17.3 250 33 17 7.3 4.0
27000 -25.9 -14.6 250 24 12 7.7 4.2 | -25.3 -13.5 245 32 16 7.2 3.9
26000 -23.6 -10.5 245 22 12 7.7 4.2 | -23.1 -9.6 240 31 16 7.2 4.0
25000 -21.3 -6.3 245 21 11 7.7 4.2 | -21.0 -5.8 235 31 16 7.2 4.0
24000 -19.0 -2.2 240 21 11 7.3 4.0 | -18.6 -1.5 230 30 15 8.4 4.6
23000 -16.8 1.8 230 23 12 7.3 4.0 | -16.1 3.0 230 28 14 8.5 4.7
22000 -14.6 5.7 225 24 12 7.3 4.0 | -13.5 7.7 225 26 13 8.5 4.7
21000 -12.0 10.4 220 28 14 7.1 3.9 | -11.2 11.8 225 25 13 7.6 4.1
20000 -9.9 14.2 220 32 17 7.1 3.9 | -8.3 17.1 225 25 13 7.5 4.1
19500 -8.9 16.0 220 35 18 7.1 3.9 | -7.2 19.0 220 25 13 7.5 4.1
19000 -7.8 18.0 220 36 19 8.8 4.8 | -6.1 21.0 220 25 13 8.0 4.4
18500 -6.4 20.5 215 37 19 9.3 5.1 | -4.9 23.2 220 26 13 8.1 4.5
18000 -5.1 22.8 215 37 19 9.3 5.1 | -3.6 25.5 220 27 14 8.1 4.5
17500 -3.7 25.3 215 37 19 9.3 5.1 | -2.4 27.7 220 27 14 8.1 4.4
17000 -2.4 27.7 215 36 19 9.4 5.1 | -1.2 29.8 220 28 15 8.1 4.4
16500 -1.0 30.2 210 36 18 9.3 5.1 | -0.0 32.0 220 29 15 8.0 4.4
16000 0.3 32.5 210 35 18 9.2 5.1 | 1.2 34.2 220 30 16 7.9 4.3
15500 1.7 35.1 210 34 18 9.1 5.0 | 2.4 36.3 220 31 16 7.9 4.3
15000 3.0 37.4 210 32 16 8.6 4.7 | 3.5 38.3 215 31 16 7.9 4.4
14500 4.3 39.7 205 30 15 8.7 4.8 | 4.7 40.5 215 31 16 7.9 4.4
14000 5.6 42.1 205 28 14 8.2 4.5 | 5.9 42.6 215 30 15 8.5 4.6
13500 6.9 44.4 205 27 14 7.2 4.0 | 7.1 44.8 215 28 15 7.5 4.1
13000 8.6 47.5 210 27 14 12.1 6.6 | 8.8 47.8 215 27 14 12.5 6.9
12500 9.7 49.5 210 24 13 7.7 4.2 | 10.0 50.0 215 25 13 8.7 4.8
12000 10.9 51.6 210 22 11 9.1 5.0 | 11.3 52.3 215 24 12 10.4 5.7
11750 11.6 52.9 210 21 11 9.6 5.3 | 12.1 53.8 215 23 12 10.7 5.9
11500 12.3 54.1 215 20 10 8.7 4.8 | 12.8 55.0 215 22 12 9.0 4.9
11250 13.0 55.4 215 19 10 8.8 4.8 | 13.5 56.3 210 22 11 9.3 5.1
11000 13.6 56.5 215 18 9 8.8 4.8 | 14.2 57.6 210 22 11 9.1 5.0
10750 14.3 57.7 215 17 9 8.8 4.8 | 14.8 58.6 210 22 11 8.6 4.7
10500 14.9 58.8 215 16 8 8.8 4.9 | 15.5 59.9 210 22 11 9.7 5.3
10250 15.6 60.1 210 15 8 9.3 5.1 | 16.3 61.3 210 21 11 11.0 6.0
10000 16.3 61.3 210 14 7 8.4 4.6 | 17.1 62.8 210 21 11 10.3 5.6
9750 16.9 62.4 215 13 7 7.3 4.0 | 17.8 64.0 210 21 11 9.6 5.3
9500 17.4 63.3 220 12 6 7.8 4.3 | 18.5 65.3 210 21 11 9.4 5.2
9250 18.0 64.4 225 11 6 6.4 3.5 | 19.3 66.7 210 21 11 10.6 5.8
9000 18.4 65.1 230 12 6 6.0 3.3 | 20.1 68.2 205 20 10 11.4 6.3
8750 18.9 66.0 235 11 6 7.1 3.9 | 20.9 69.6 205 20 10 10.5 5.8
8500 19.3 66.7 240 11 6 7.0 3.8 | 21.7 71.1 205 20 10 11.4 6.2
8250 19.8 67.6 240 11 6 7.0 3.9 | 22.5 72.5 205 19 10 8.5 4.7
8000 20.4 68.7 245 10 5 12.7 7.0 | 23.2 73.8 205 19 10 15.2 8.3
7750 21.7 71.1 240 9 4 22.3 12.2 | 25.1 77.2 205 17 9 35.2 19.3
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
06/17/2024 at 1500 MDT | 06/17/2024 at 1800 MDT
|
CAPE... +0.5 LI... +0.3 | CAPE... 0.0 LI... -0.5
CINH... -1.6 K Index... +9.8 | CINH... 0.0 K Index... +13.3
|
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 -62.1 -79.8 240 44 23 2.4 1.3 | -61.4 -78.5 240 41 21 1.9 1.1
45000 -58.5 -73.3 250 50 26 2.5 1.4 | -58.4 -73.1 250 52 27 2.4 1.3
40000 -54.0 -65.2 250 45 23 7.6 4.2 | -54.1 -65.4 250 51 26 7.6 4.2
38000 -49.6 -57.3 255 46 24 7.3 4.0 | -49.7 -57.5 250 51 26 7.3 4.0
36000 -45.3 -49.5 255 47 24 7.3 4.0 | -45.3 -49.5 255 51 26 7.3 4.0
34000 -40.8 -41.4 255 47 24 7.5 4.1 | -40.4 -40.7 255 50 26 8.4 4.6
32000 -36.3 -33.3 255 46 24 7.5 4.1 | -35.4 -31.7 255 48 25 8.4 4.6
30000 -31.6 -24.9 250 43 22 8.1 4.4 | -30.6 -23.1 250 45 23 7.9 4.3
29000 -29.2 -20.6 250 41 21 8.1 4.4 | -28.2 -18.8 250 43 22 7.9 4.3
28000 -26.7 -16.1 250 39 20 8.2 4.5 | -25.8 -14.4 245 41 21 7.9 4.3
27000 -24.4 -11.9 245 38 19 7.6 4.2 | -23.5 -10.3 245 40 21 7.6 4.2
26000 -22.1 -7.8 245 37 19 7.6 4.2 | -21.3 -6.3 240 39 20 7.7 4.2
25000 -19.8 -3.6 240 35 18 7.6 4.2 | -18.4 -1.1 235 37 19 7.8 4.3
24000 -17.1 1.2 235 34 18 7.1 3.9 | -16.4 2.5 235 36 19 6.4 3.5
23000 -14.9 5.2 235 34 18 7.1 3.9 | -14.4 6.1 240 36 19 6.4 3.5
22000 -12.8 9.0 230 34 17 7.2 3.9 | -12.5 9.5 240 36 18 6.4 3.5
21000 -10.7 12.7 230 33 17 7.4 4.1 | -10.6 12.9 240 33 17 6.5 3.6
20000 -8.5 16.7 235 33 17 7.4 4.1 | -8.7 16.3 240 29 15 6.7 3.7
19500 -7.4 18.7 235 33 17 7.4 4.1 | -7.7 18.1 240 27 14 6.9 3.8
19000 -6.3 20.7 235 32 17 7.5 4.1 | -6.8 19.8 240 26 13 7.9 4.3
18500 -5.2 22.6 235 30 16 7.6 4.2 | -5.5 22.1 240 25 13 8.8 4.8
18000 -4.0 24.8 240 29 15 7.4 4.1 | -4.2 24.4 240 25 13 8.8 4.8
17500 -2.8 27.0 240 27 14 9.6 5.3 | -2.8 27.0 240 24 13 9.4 5.2
17000 -1.4 29.5 235 24 12 9.4 5.1 | -1.4 29.5 240 25 13 9.4 5.1
16500 -0.0 32.0 235 22 11 9.0 4.9 | -0.0 32.0 235 25 13 9.4 5.1
16000 1.3 34.3 230 21 11 8.8 4.8 | 1.4 34.5 235 25 13 9.4 5.1
15500 2.5 36.5 225 20 10 8.8 4.9 | 2.8 37.0 230 25 13 9.4 5.1
15000 3.9 39.0 225 20 10 9.8 5.4 | 4.2 39.6 230 26 13 9.7 5.3
14500 5.4 41.7 225 20 10 9.7 5.3 | 5.7 42.3 225 26 13 9.6 5.3
14000 6.8 44.2 220 20 10 9.5 5.2 | 7.2 45.0 225 26 14 11.3 6.2
13500 8.3 46.9 220 20 10 8.5 4.7 | 8.9 48.0 220 26 14 12.7 6.9
13000 10.1 50.2 215 20 10 12.6 6.9 | 10.0 50.0 220 26 13 5.5 3.0
12500 11.3 52.3 215 20 10 8.6 4.7 | 11.5 52.7 220 26 13 9.6 5.3
12000 12.6 54.7 210 19 10 10.0 5.5 | 13.0 55.4 215 26 13 12.3 6.8
11750 13.4 56.1 210 19 10 10.8 5.9 | 14.0 57.2 215 26 13 11.7 6.4
11500 14.1 57.4 205 19 10 9.0 4.9 | 14.6 58.3 215 26 13 7.9 4.3
11250 14.8 58.6 205 19 10 9.4 5.2 | 15.3 59.5 215 26 13 8.9 4.9
11000 15.5 59.9 205 19 10 9.2 5.1 | 15.9 60.6 210 26 13 8.8 4.8
10750 16.2 61.2 205 19 10 8.7 4.8 | 16.6 61.9 210 25 13 9.2 5.1
10500 16.9 62.4 200 19 10 9.8 5.4 | 17.3 63.1 210 25 13 9.7 5.3
10250 17.7 63.9 200 19 10 11.1 6.1 | 18.1 64.6 210 25 13 10.1 5.5
10000 18.5 65.3 200 19 10 10.5 5.7 | 18.8 65.8 205 25 13 10.0 5.5
9750 19.2 66.6 200 19 10 9.7 5.3 | 19.6 67.3 205 25 13 9.8 5.4
9500 19.9 67.8 200 19 10 9.2 5.1 | 20.3 68.5 205 25 13 9.5 5.2
9250 20.7 69.3 200 19 10 10.3 5.7 | 21.0 69.8 205 24 13 10.2 5.6
9000 21.5 70.7 195 19 10 11.2 6.1 | 21.8 71.2 205 24 12 10.7 5.9
8750 22.3 72.1 195 19 10 10.6 5.8 | 22.6 72.7 200 24 12 10.2 5.6
8500 23.1 73.6 195 19 10 11.1 6.1 | 23.3 73.9 200 24 12 10.3 5.6
8250 23.9 75.0 195 18 9 9.2 5.0 | 24.1 75.4 200 23 12 9.5 5.2
8000 24.6 76.3 195 18 9 13.7 7.5 | 24.8 76.6 200 22 12 10.2 5.6
7750 26.2 79.2 195 17 9 29.7 16.3 | 25.7 78.3 200 20 10 16.0 8.8
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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