Soaring Guidance
Issued by NWS Pueblo, CO
Issued by NWS Pueblo, CO
299
UXUS97 KPUB 161206
SRGPUB
Soaring Forecast
National Weather Service Pueblo, Colorado
0606 MDT Sunday, June 16, 2024
This forecast is for the Air Force Academy for Sunday, June 16, 2024:
If the trigger temperature of 76.7 F/24.8 C is reached...then
Thermal Soaring Index....................... Excellent
Maximum rate of lift........................ 1661 ft/min (8.4 m/s)
Maximum height of thermals.................. 24472 ft MSL (16886 ft AGL)
Forecast maximum temperature................... 92.0 F/33.8 C
Time of trigger temperature.................... 0930 MDT
Time of overdevelopment........................ None
Middle/high clouds during soaring window....... None
Surface winds during soaring window............ 20 mph or less
Height of the -3 thermal index................. 22570 ft MSL (14984 ft AGL)
Thermal soaring outlook for Monday 06/17....... Excellent
Wave Soaring Index............................. Not available
Remarks...
Sunrise/Sunset.................... 05:33:16 / 20:27:06 MDT
Total possible sunshine........... 14 hr 53 min 51 sec (893 min 51 sec)
Altitude of sun at 13:00:11 MDT... 74.40 degrees
Upper air data from numerical model forecast valid on 06/16/2024 at 0600 MDT
Freezing level.................. 16181 ft MSL (8595 ft AGL)
Convective condensation level... 19417 ft MSL (11831 ft AGL)
Lifted condensation level....... 22329 ft MSL (14743 ft AGL)
Lifted index.................... -2.8
K index......................... +12.4
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 -61.5 -78.7 265 36 18 0.9 0.5 M M M M M
45000 -59.4 -74.9 275 42 22 2.7 1.5 M M M M M
40000 -54.8 -66.6 285 55 28 8.1 4.4 M M M M M
38000 -50.2 -58.4 285 50 26 7.7 4.2 M M M M M
36000 -45.0 -49.0 285 43 22 7.7 4.2 M M M M M
34000 -40.3 -40.5 285 39 20 7.8 4.3 M M M M M
32000 -35.7 -32.3 280 34 18 7.7 4.2 M M M M M
30000 -31.1 -24.0 275 30 16 7.6 4.2 37.3 99.1 3.0 M M
29000 -28.8 -19.8 275 28 15 7.6 4.2 36.5 97.7 2.4 M M
28000 -26.6 -15.9 275 26 14 7.8 4.3 35.8 96.5 1.9 M M
27000 -24.1 -11.4 275 26 13 8.1 4.5 35.1 95.2 1.4 M M
26000 -21.7 -7.1 275 26 13 8.2 4.5 34.5 94.1 0.9 M M
25000 -19.2 -2.6 270 26 13 8.4 4.6 34.0 93.2 0.5 M M
24000 -17.4 0.7 270 25 13 4.8 2.6 32.6 90.7 -0.7 1632 8.3
23000 -16.0 3.2 270 25 13 4.8 2.7 30.8 87.4 -2.2 1560 7.9
22000 -14.6 5.7 270 24 13 4.7 2.6 29.2 84.5 -3.7 1488 7.6
21000 -12.7 9.1 270 24 12 7.1 3.9 28.0 82.3 -4.8 1402 7.1
20000 -10.2 13.6 270 24 12 7.1 3.9 26.8 80.2 -6.0 1288 6.5
19500 -9.1 15.6 270 24 12 6.9 3.8 26.4 79.5 -6.4 1243 6.3
19000 -7.9 17.8 270 23 12 9.9 5.4 26.2 79.1 -6.7 1191 6.1
18500 -6.5 20.3 270 22 12 9.6 5.3 26.1 79.1 -6.8 1133 5.8
18000 -5.1 22.8 270 21 11 9.7 5.3 26.1 79.0 -6.8 1076 5.5
17500 -3.6 25.5 270 20 10 9.8 5.4 26.1 79.0 -6.9 1017 5.2
17000 -2.1 28.2 270 19 10 9.9 5.4 26.1 79.0 -6.9 959 4.9
16500 -0.7 30.7 270 18 9 9.2 5.0 26.1 79.0 -7.0 902 4.6
16000 0.6 33.1 270 17 9 9.3 5.1 26.0 78.8 -7.1 846 4.3
15500 2.0 35.6 270 16 8 9.4 5.1 25.9 78.7 -7.3 790 4.0
15000 3.4 38.1 270 16 8 9.4 5.2 25.9 78.6 -7.4 733 3.7
14500 4.8 40.6 270 15 8 9.4 5.2 25.8 78.5 -7.5 677 3.4
14000 6.2 43.2 265 16 8 9.5 5.2 25.8 78.4 -7.5 619 3.1
13500 7.6 45.7 265 16 8 9.5 5.2 25.7 78.3 -7.6 562 2.9
13000 9.2 48.6 260 16 8 10.4 5.7 25.9 78.5 -7.6 501 2.5
12500 10.6 51.1 260 17 9 9.3 5.1 25.8 78.4 -7.7 445 2.3
12000 11.8 53.2 255 17 9 7.4 4.0 25.6 78.0 -7.9 392 2.0
11750 12.4 54.3 255 17 9 8.3 4.6 25.4 77.7 -8.1 368 1.9
11500 13.1 55.6 250 17 9 10.1 5.5 25.4 77.7 -8.2 340 1.7
11250 13.8 56.8 250 17 9 9.2 5.1 25.4 77.7 -8.2 311 1.6
11000 14.4 57.9 250 17 9 7.4 4.1 25.3 77.5 -8.4 286 1.5
10750 14.9 58.8 245 17 9 6.9 3.8 25.1 77.1 -8.6 263 1.3
10500 15.4 59.7 245 16 8 8.2 4.5 24.9 76.8 -8.8 240 1.2
10250 16.1 61.0 245 16 8 9.3 5.1 24.8 76.7 -8.9 213 1.1
10000 16.7 62.1 240 15 8 8.0 4.4 24.7 76.5 -9.1 187 0.9
9750 17.3 63.1 240 14 7 7.6 4.2 24.6 76.2 -9.3 163 0.8
9500 17.8 64.0 235 14 7 7.5 4.1 24.4 75.9 -9.5 139 0.7
9250 18.4 65.1 235 13 7 8.3 4.5 24.3 75.7 -9.7 115 0.6
9000 19.0 66.2 230 12 6 7.6 4.2 24.2 75.5 -9.8 90 0.5
8750 19.4 66.9 225 12 6 5.6 3.1 23.9 75.0 -10.2 69 0.4
8500 19.8 67.6 225 12 6 8.5 4.7 23.6 74.6 -10.5 49 0.2
8250 20.3 68.5 220 12 6 -1.0 -0.6 23.4 74.1 -10.8 28 0.1
8000 19.3 66.7 220 11 5 -25.5 -14.0 21.6 71.0 -12.5 51 0.3
7750 16.7 62.1 230 8 4 -37.5 -20.6 18.4 65.1 -15.8 120 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 * * * * * *
06/16/2024 at 0900 MDT | 06/16/2024 at 1200 MDT
|
CAPE... +120.4 LI... -1.0 | CAPE... +18.9 LI... -0.7
CINH... -42.9 K Index... +14.6 | CINH... -0.2 K Index... +19.4
|
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 -62.5 -80.5 265 37 19 1.1 0.6 | -62.8 -81.0 265 35 18 0.5 0.2
45000 -59.9 -75.8 270 42 22 3.1 1.7 | -60.7 -77.3 275 41 21 4.0 2.2
40000 -54.7 -66.5 280 48 25 7.8 4.3 | -54.3 -65.7 275 44 23 7.5 4.1
38000 -50.1 -58.2 280 45 23 7.6 4.2 | -49.9 -57.8 275 43 22 7.3 4.0
36000 -45.5 -49.9 280 42 22 7.6 4.2 | -45.5 -49.9 275 42 21 7.4 4.0
34000 -40.3 -40.5 275 41 21 7.8 4.3 | -40.3 -40.5 270 43 22 7.9 4.3
32000 -35.6 -32.1 275 41 21 7.7 4.2 | -35.6 -32.1 270 45 23 7.8 4.3
30000 -30.9 -23.6 270 38 19 7.9 4.3 | -30.6 -23.1 265 42 22 8.4 4.6
29000 -28.6 -19.5 270 36 19 7.9 4.4 | -28.1 -18.6 265 40 21 8.4 4.6
28000 -26.2 -15.2 265 34 18 7.9 4.3 | -25.5 -13.9 265 39 20 7.8 4.3
27000 -23.9 -11.0 265 31 16 7.7 4.2 | -23.5 -10.3 260 35 18 7.0 3.8
26000 -21.6 -6.9 260 28 14 7.7 4.2 | -21.4 -6.5 255 33 17 7.0 3.8
25000 -19.2 -2.6 260 25 13 7.8 4.3 | -19.3 -2.7 250 30 15 7.1 3.9
24000 -17.1 1.2 260 23 12 7.0 3.8 | -17.4 0.7 250 28 14 6.1 3.4
23000 -15.0 5.0 265 23 12 7.0 3.8 | -15.5 4.1 250 26 14 6.1 3.4
22000 -12.9 8.8 265 23 12 7.3 4.0 | -13.7 7.3 250 25 13 6.1 3.4
21000 -11.3 11.7 265 21 11 4.9 2.7 | -11.8 10.8 250 23 12 6.4 3.5
20000 -9.9 14.2 265 19 10 5.1 2.8 | -9.5 14.9 245 20 10 6.6 3.6
19500 -8.8 16.2 265 17 9 5.2 2.8 | -8.6 16.5 240 19 10 6.6 3.6
19000 -7.7 18.1 265 16 8 10.0 5.5 | -7.5 18.5 240 17 9 9.2 5.0
18500 -6.3 20.7 260 15 8 9.6 5.2 | -6.2 20.8 240 16 8 9.0 4.9
18000 -4.9 23.2 260 15 8 9.6 5.3 | -4.9 23.2 240 14 7 9.4 5.2
17500 -3.5 25.7 260 14 7 9.6 5.3 | -3.5 25.7 240 14 7 9.7 5.3
17000 -2.1 28.2 260 14 7 9.6 5.3 | -2.0 28.4 240 13 7 9.8 5.4
16500 -0.6 30.9 255 14 7 9.6 5.3 | -0.6 30.9 240 13 7 9.3 5.1
16000 0.8 33.4 255 13 7 9.6 5.3 | 0.8 33.4 235 13 7 9.4 5.1
15500 2.2 36.0 255 12 6 9.7 5.3 | 2.2 36.0 235 12 6 9.9 5.4
15000 3.7 38.7 255 12 6 9.8 5.4 | 3.7 38.7 235 12 6 10.1 5.5
14500 5.2 41.4 255 11 6 9.6 5.2 | 5.2 41.4 235 12 6 10.0 5.5
14000 6.5 43.7 255 12 6 9.1 5.0 | 6.7 44.1 235 11 6 9.7 5.3
13500 7.9 46.2 255 12 6 9.1 5.0 | 8.1 46.6 235 11 6 9.7 5.3
13000 9.3 48.7 255 13 6 8.9 4.9 | 9.9 49.8 230 11 6 10.9 6.0
12500 10.5 50.9 255 13 7 8.5 4.7 | 11.2 52.2 230 11 5 8.7 4.8
12000 11.8 53.2 255 14 7 8.3 4.6 | 12.5 54.5 230 10 5 9.3 5.1
11750 12.4 54.3 250 15 7 8.7 4.8 | 13.2 55.8 225 10 5 9.6 5.3
11500 13.1 55.6 250 15 8 9.7 5.3 | 13.9 57.0 225 10 5 10.4 5.7
11250 13.8 56.8 250 16 8 8.7 4.8 | 14.7 58.5 225 10 5 9.8 5.4
11000 14.4 57.9 245 17 9 7.2 4.0 | 15.4 59.7 225 10 5 9.2 5.0
10750 14.9 58.8 245 17 9 6.7 3.7 | 16.1 61.0 225 10 5 8.6 4.7
10500 15.4 59.7 245 18 9 8.3 4.6 | 16.7 62.1 225 9 5 10.5 5.7
10250 16.1 61.0 245 19 10 9.5 5.2 | 17.6 63.7 225 9 5 11.7 6.4
10000 16.8 62.2 245 20 10 8.1 4.4 | 18.4 65.1 220 9 5 9.8 5.4
9750 17.3 63.1 250 20 10 7.9 4.3 | 19.1 66.4 220 9 5 9.5 5.2
9500 17.9 64.2 250 20 10 7.5 4.1 | 19.8 67.6 220 9 5 9.1 5.0
9250 18.5 65.3 250 20 10 9.1 5.0 | 20.6 69.1 220 9 5 11.2 6.1
9000 19.1 66.4 245 20 10 8.5 4.7 | 21.4 70.5 220 9 4 11.5 6.3
8750 19.6 67.3 245 18 9 6.5 3.6 | 22.2 72.0 215 8 4 9.9 5.4
8500 20.0 68.0 245 17 9 7.1 3.9 | 23.0 73.4 215 8 4 10.0 5.5
8250 20.5 68.9 245 16 8 7.6 4.2 | 23.7 74.7 215 8 4 11.1 6.1
8000 21.2 70.2 240 13 7 13.2 7.2 | 24.7 76.5 215 8 4 18.4 10.1
7750 22.4 72.3 235 11 5 20.3 11.2 | 26.4 79.5 215 7 4 26.8 14.7
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
06/16/2024 at 1500 MDT | 06/16/2024 at 1800 MDT
|
CAPE... +65.8 LI... -0.7 | CAPE... +101.5 LI... -0.5
CINH... 0.0 K Index... +19.9 | CINH... -6.3 K Index... +20.8
|
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 -62.8 -81.0 260 37 19 0.3 0.2 | -62.0 -79.6 260 39 20 2.0 1.1
45000 -60.6 -77.1 270 40 21 4.4 2.4 | -58.4 -73.1 260 42 22 3.5 1.9
40000 -53.7 -64.7 260 41 21 7.0 3.9 | -52.8 -63.0 235 40 21 6.3 3.5
38000 -49.5 -57.1 260 42 22 6.9 3.8 | -49.1 -56.4 235 42 22 6.2 3.4
36000 -45.4 -49.7 260 43 22 6.9 3.8 | -45.4 -49.7 240 45 23 6.2 3.4
34000 -40.2 -40.4 260 43 22 7.9 4.3 | -40.5 -40.9 240 44 22 7.6 4.2
32000 -35.5 -31.9 260 43 22 7.8 4.3 | -35.9 -32.6 245 42 22 7.6 4.2
30000 -30.6 -23.1 255 43 22 8.2 4.5 | -31.1 -24.0 245 40 21 8.1 4.5
29000 -28.2 -18.8 255 42 22 8.2 4.5 | -28.7 -19.7 250 40 20 8.1 4.5
28000 -25.7 -14.3 255 42 22 7.7 4.2 | -26.2 -15.2 250 39 20 7.8 4.3
27000 -23.7 -10.7 255 40 21 6.7 3.7 | -24.1 -11.4 250 37 19 7.1 3.9
26000 -21.7 -7.1 250 38 19 6.7 3.7 | -22.0 -7.6 250 36 18 7.1 3.9
25000 -19.7 -3.5 250 35 18 6.8 3.7 | -19.9 -3.8 250 34 17 7.1 3.9
24000 -17.8 -0.0 250 32 17 6.2 3.4 | -17.8 -0.0 250 31 16 6.8 3.7
23000 -16.0 3.2 250 29 15 6.3 3.4 | -15.8 3.6 245 28 14 6.9 3.8
22000 -14.1 6.6 250 26 13 6.1 3.4 | -13.8 7.2 240 24 13 6.8 3.7
21000 -11.9 10.6 250 23 12 8.2 4.5 | -11.5 11.3 240 23 12 8.4 4.6
20000 -9.0 15.8 245 20 10 8.3 4.5 | -8.5 16.7 240 24 12 8.5 4.7
19500 -7.8 18.0 240 19 10 8.2 4.5 | -7.3 18.9 240 24 12 8.5 4.7
19000 -6.5 20.3 240 18 9 9.5 5.2 | -6.0 21.2 235 24 12 9.0 5.0
18500 -5.1 22.8 240 18 9 9.4 5.1 | -4.7 23.5 235 24 12 9.0 4.9
18000 -3.7 25.3 240 18 9 9.3 5.1 | -3.3 26.1 235 24 12 9.2 5.0
17500 -2.3 27.9 235 18 9 9.3 5.1 | -1.9 28.6 235 24 12 9.4 5.2
17000 -1.0 30.2 235 18 9 9.3 5.1 | -0.5 31.1 235 24 12 9.4 5.2
16500 0.4 32.7 230 18 9 9.6 5.3 | 0.9 33.6 230 24 12 9.8 5.4
16000 1.9 35.4 230 18 9 9.6 5.2 | 2.3 36.1 230 24 12 9.8 5.4
15500 3.3 37.9 225 18 9 9.7 5.3 | 3.8 38.8 225 24 12 9.6 5.3
15000 4.8 40.6 225 17 9 9.8 5.4 | 5.2 41.4 225 24 12 9.6 5.2
14500 6.2 43.2 220 17 9 9.8 5.4 | 6.6 43.9 225 23 12 9.6 5.2
14000 7.7 45.9 215 17 9 9.7 5.3 | 8.1 46.6 220 23 12 9.5 5.2
13500 9.1 48.4 215 17 9 9.5 5.2 | 9.5 49.1 220 23 12 8.9 4.9
13000 10.8 51.4 210 17 9 10.7 5.9 | 11.2 52.2 220 23 12 11.6 6.4
12500 12.1 53.8 205 17 9 9.0 5.0 | 12.5 54.5 215 23 12 8.8 4.8
12000 13.4 56.1 200 17 9 8.6 4.7 | 13.8 56.8 215 22 12 9.2 5.0
11750 14.1 57.4 200 17 9 9.6 5.3 | 14.5 58.1 210 22 12 9.4 5.2
11500 14.9 58.8 200 17 9 10.9 6.0 | 15.3 59.5 210 22 11 9.7 5.3
11250 15.7 60.3 195 17 9 10.1 5.5 | 16.0 60.8 210 22 11 9.5 5.2
11000 16.4 61.5 195 17 9 9.0 4.9 | 16.7 62.1 210 22 11 9.0 4.9
10750 17.0 62.6 195 17 9 8.1 4.4 | 17.3 63.1 205 22 11 8.3 4.5
10500 17.7 63.9 195 17 9 9.8 5.4 | 17.9 64.2 205 21 11 10.0 5.5
10250 18.5 65.3 190 17 9 11.3 6.2 | 18.8 65.8 205 21 11 11.6 6.4
10000 19.3 66.7 190 17 9 10.2 5.6 | 19.6 67.3 200 21 11 9.9 5.4
9750 20.0 68.0 190 17 9 9.9 5.4 | 20.3 68.5 200 21 11 9.2 5.0
9500 20.8 69.4 190 17 9 10.0 5.5 | 21.0 69.8 200 21 11 9.1 5.0
9250 21.5 70.7 190 17 9 10.0 5.5 | 21.7 71.1 195 21 11 10.5 5.7
9000 22.3 72.1 190 17 9 10.2 5.6 | 22.5 72.5 195 20 11 10.7 5.9
8750 23.1 73.6 185 17 9 10.5 5.8 | 23.2 73.8 195 20 10 9.6 5.3
8500 23.8 74.8 185 17 9 9.9 5.4 | 24.0 75.2 195 20 10 9.9 5.5
8250 24.6 76.3 185 17 9 12.2 6.7 | 24.7 76.5 190 20 10 9.8 5.4
8000 25.7 78.3 185 17 8 19.2 10.5 | 25.5 77.9 190 19 10 12.2 6.7
7750 27.3 81.1 185 15 8 24.1 13.2 | 26.5 79.7 190 16 8 16.4 9.0
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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