Soaring Guidance
Issued by NWS Pueblo, CO
Issued by NWS Pueblo, CO
360
UXUS97 KPUB 261203
SRGPUB
Soaring Forecast
National Weather Service Pueblo, Colorado
0603 MDT Wednesday, June 26, 2024
This forecast is for the Air Force Academy for Wednesday, June 26, 2024:
If the trigger temperature of 76.6 F/24.8 C is reached...then
Thermal Soaring Index....................... Excellent
Maximum rate of lift........................ 1199 ft/min (6.1 m/s)
Maximum height of thermals.................. 21997 ft MSL (14374 ft AGL)
Forecast maximum temperature................... 89.0 F/32.1 C
Time of trigger temperature.................... 0845 MDT
Time of overdevelopment........................ 1600 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................. 19131 ft MSL (11508 ft AGL)
Thermal soaring outlook for Thursday 06/27..... Excellent
Wave Soaring Index............................. Not available
Remarks...
Sunrise/Sunset.................... 05:35:41 / 20:28:59 MDT
Total possible sunshine........... 14 hr 53 min 19 sec (893 min 19 sec)
Altitude of sun at 13:02:20 MDT... 74.33 degrees
Upper air data from numerical model forecast valid on 06/26/2024 at 0600 MDT
Freezing level.................. 16620 ft MSL (8997 ft AGL)
Convective condensation level... 18554 ft MSL (10931 ft AGL)
Lifted condensation level....... 20209 ft MSL (12586 ft AGL)
Lifted index.................... -0.7
K index......................... +22.9
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 -65.4 -85.7 265 27 14 2.7 1.5 M M M M M
45000 -58.4 -73.1 270 35 18 7.5 4.1 M M M M M
40000 -47.3 -53.1 285 45 23 6.9 3.8 M M M M M
38000 -43.2 -45.8 285 50 26 6.9 3.8 M M M M M
36000 -38.5 -37.3 285 55 28 6.8 3.7 M M M M M
34000 -34.4 -29.9 290 52 27 6.8 3.7 M M M M M
32000 -30.3 -22.5 290 49 25 7.7 4.2 45.1 113.2 10.2 M M
30000 -25.8 -14.4 295 40 21 7.6 4.2 43.3 109.9 9.1 M M
29000 -23.5 -10.3 300 36 19 7.6 4.2 42.6 108.6 8.6 M M
28000 -21.3 -6.3 305 33 17 5.4 3.0 41.6 106.9 8.0 M M
27000 -19.7 -3.5 305 30 16 5.7 3.1 40.0 104.0 6.7 M M
26000 -18.0 -0.4 310 28 14 5.7 3.1 38.5 101.3 5.6 M M
25000 -16.3 2.7 310 25 13 5.3 2.9 37.1 98.9 4.5 M M
24000 -14.8 5.4 315 23 12 4.9 2.7 35.3 95.5 3.0 M M
23000 -13.4 7.9 315 21 11 5.0 2.7 33.6 92.4 1.5 M M
22000 -12.0 10.4 315 18 9 5.8 3.2 32.0 89.6 0.1 M M
21000 -9.6 14.7 315 19 10 6.6 3.6 30.5 86.9 -1.2 1301 6.6
20000 -7.7 18.1 315 19 10 6.6 3.6 29.5 85.0 -2.2 1215 6.2
19500 -6.7 19.9 315 19 10 6.9 3.8 29.0 84.2 -2.7 1171 5.9
19000 -5.7 21.7 310 19 10 7.1 3.9 28.5 83.3 -3.2 1127 5.7
18500 -4.7 23.5 305 18 9 7.0 3.9 28.1 82.6 -3.7 1082 5.5
18000 -3.6 25.5 305 17 9 9.4 5.2 27.8 82.1 -4.0 1033 5.2
17500 -2.3 27.9 300 16 8 9.2 5.1 27.7 81.9 -4.2 979 5.0
17000 -1.0 30.2 295 14 7 9.4 5.2 27.7 81.8 -4.4 925 4.7
16500 0.4 32.7 295 14 7 9.6 5.3 27.6 81.7 -4.5 868 4.4
16000 1.8 35.2 290 13 7 9.6 5.3 27.6 81.7 -4.6 812 4.1
15500 3.1 37.6 290 12 6 8.8 4.8 27.5 81.5 -4.7 758 3.8
15000 4.4 39.9 280 11 6 8.9 4.9 27.4 81.3 -4.9 704 3.6
14500 5.7 42.3 275 10 5 8.0 4.4 27.2 80.9 -5.1 652 3.3
14000 6.9 44.4 270 8 4 8.0 4.4 26.9 80.4 -5.4 602 3.1
13500 8.0 46.4 255 7 3 8.2 4.5 26.6 80.0 -5.7 551 2.8
13000 9.3 48.7 240 5 3 8.3 4.5 26.4 79.6 -6.0 499 2.5
12500 10.5 50.9 230 5 3 8.4 4.6 26.2 79.1 -6.2 447 2.3
12000 11.9 53.4 210 5 2 9.0 4.9 26.0 78.8 -6.4 393 2.0
11750 12.5 54.5 200 5 2 8.0 4.4 25.9 78.7 -6.5 366 1.9
11500 13.1 55.6 190 5 3 7.4 4.0 25.7 78.3 -6.7 342 1.7
11250 13.7 56.7 185 5 3 8.8 4.8 25.6 78.1 -6.8 316 1.6
11000 14.4 57.9 175 5 3 9.1 5.0 25.6 78.0 -6.8 288 1.5
10750 15.1 59.2 170 5 3 9.5 5.2 25.5 77.9 -6.9 260 1.3
10500 15.7 60.3 165 6 3 7.4 4.0 25.5 77.8 -6.9 232 1.2
10250 16.2 61.2 160 6 3 6.8 3.7 25.2 77.3 -7.2 210 1.1
10000 16.8 62.2 155 5 3 8.5 4.7 25.1 77.1 -7.3 184 0.9
9750 17.5 63.5 155 4 2 8.1 4.4 24.9 76.9 -7.5 159 0.8
9500 18.1 64.6 150 4 2 8.1 4.5 24.8 76.7 -7.6 133 0.7
9250 18.6 65.5 145 3 1 6.8 3.7 24.7 76.4 -7.8 110 0.6
9000 19.0 66.2 130 2 1 5.9 3.2 24.4 75.9 -8.1 89 0.5
8750 19.4 66.9 095 2 1 5.7 3.1 24.1 75.3 -8.5 70 0.4
8500 19.8 67.6 060 2 1 6.8 3.7 23.8 74.8 -8.8 50 0.3
8250 20.4 68.7 025 2 1 6.7 3.7 23.6 74.5 -9.0 27 0.1
8000 20.4 68.7 350 3 1 -9.4 -5.1 22.9 73.3 -9.7 18 0.1
7750 18.8 65.8 305 4 2 -31.8 -17.5 20.6 69.0 -12.2 60 0.3
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 * * * * * *
06/26/2024 at 0900 MDT | 06/26/2024 at 1200 MDT
|
CAPE... +53.8 LI... -0.2 | CAPE... +297.2 LI... -1.4
CINH... -88.3 K Index... +12.9 | CINH... -38.1 K Index... +16.9
|
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 -65.6 -86.1 275 28 15 2.8 1.5 | -64.9 -84.8 275 32 16 2.6 1.4
45000 -58.5 -73.3 280 42 22 7.2 3.9 | -58.4 -73.1 280 46 24 6.8 3.7
40000 -48.0 -54.4 285 47 24 6.6 3.6 | -48.3 -54.9 280 52 27 6.6 3.6
38000 -44.0 -47.2 285 50 26 6.6 3.6 | -44.3 -47.7 280 52 27 6.6 3.6
36000 -40.0 -40.0 285 53 27 6.5 3.6 | -39.8 -39.6 280 52 27 7.1 3.9
34000 -35.8 -32.4 285 46 24 6.3 3.5 | -35.6 -32.1 280 45 23 7.1 3.9
32000 -31.9 -25.4 285 41 21 7.9 4.3 | -31.4 -24.5 280 38 19 7.5 4.1
30000 -27.1 -16.8 290 36 18 8.1 4.4 | -27.1 -16.8 280 33 17 7.3 4.0
29000 -24.7 -12.5 295 33 17 8.1 4.4 | -24.9 -12.8 280 31 16 7.3 4.0
28000 -22.4 -8.3 295 31 16 6.5 3.6 | -22.8 -9.0 280 29 15 6.4 3.5
27000 -20.5 -4.9 300 28 14 6.6 3.6 | -20.9 -5.6 285 25 13 6.5 3.6
26000 -18.5 -1.3 300 24 13 6.6 3.6 | -18.9 -2.0 290 22 11 6.5 3.6
25000 -16.5 2.3 305 21 11 6.4 3.5 | -17.0 1.4 290 18 9 6.5 3.6
24000 -14.7 5.5 310 18 9 6.2 3.4 | -15.0 5.0 290 17 9 6.5 3.6
23000 -12.8 9.0 310 15 8 6.2 3.4 | -13.1 8.4 285 15 8 6.5 3.6
22000 -10.9 12.4 320 12 6 6.4 3.5 | -10.6 12.9 280 14 7 7.0 3.8
21000 -8.6 16.5 330 14 7 6.5 3.6 | -8.6 16.5 280 13 7 6.9 3.8
20000 -6.6 20.1 335 16 8 6.5 3.6 | -6.6 20.1 275 12 6 6.9 3.8
19500 -5.6 21.9 335 17 9 7.5 4.1 | -5.5 22.1 275 12 6 7.3 4.0
19000 -4.5 23.9 335 18 9 7.9 4.4 | -4.4 24.1 285 11 6 7.5 4.1
18500 -3.3 26.1 335 19 10 8.0 4.4 | -3.3 26.1 295 10 5 7.5 4.1
18000 -2.2 28.0 335 18 9 7.8 4.3 | -2.1 28.2 300 10 5 9.1 5.0
17500 -1.1 30.0 330 16 8 7.9 4.3 | -0.8 30.6 300 10 5 8.9 4.9
17000 0.0 32.0 325 15 8 7.8 4.3 | 0.5 32.9 300 10 5 8.4 4.6
16500 1.1 34.0 315 12 6 7.9 4.3 | 1.6 34.9 290 9 5 8.1 4.5
16000 2.1 35.8 305 10 5 8.1 4.5 | 2.8 37.0 280 9 5 8.2 4.5
15500 3.3 37.9 295 9 5 8.9 4.9 | 3.9 39.0 265 9 4 8.2 4.5
15000 4.6 40.3 290 8 4 8.9 4.9 | 5.0 41.0 250 9 4 8.3 4.5
14500 5.8 42.4 280 8 4 9.3 5.1 | 6.2 43.2 240 9 4 8.5 4.7
14000 7.2 45.0 275 7 4 9.4 5.1 | 7.4 45.3 235 8 4 8.5 4.7
13500 8.6 47.5 270 7 4 8.3 4.5 | 8.6 47.5 225 8 4 7.7 4.3
13000 9.7 49.5 255 6 3 8.1 4.4 | 9.8 49.6 215 7 4 7.1 3.9
12500 11.0 51.8 250 6 3 8.2 4.5 | 10.7 51.3 205 7 4 6.7 3.7
12000 12.2 54.0 230 5 3 7.9 4.3 | 11.6 52.9 170 7 3 7.1 3.9
11750 12.8 55.0 220 5 3 6.5 3.6 | 12.1 53.8 150 7 4 6.5 3.5
11500 13.2 55.8 215 5 3 6.0 3.3 | 12.5 54.5 145 8 4 7.6 4.2
11250 13.8 56.8 205 5 3 7.8 4.3 | 13.2 55.8 140 8 4 10.1 5.5
11000 14.4 57.9 195 5 2 7.9 4.3 | 13.9 57.0 135 8 4 10.1 5.6
10750 15.0 59.0 185 5 2 8.5 4.6 | 14.7 58.5 130 9 4 10.7 5.9
10500 15.6 60.1 170 5 3 6.2 3.4 | 15.4 59.7 125 9 5 8.4 4.6
10250 16.0 60.8 165 5 3 6.4 3.5 | 16.0 60.8 125 9 5 8.4 4.6
10000 16.6 61.9 160 4 2 8.7 4.8 | 16.7 62.1 125 9 5 10.7 5.8
9750 17.2 63.0 160 3 2 8.7 4.7 | 17.5 63.5 125 9 5 10.2 5.6
9500 17.8 64.0 155 3 1 6.4 3.5 | 18.3 64.9 120 9 5 9.9 5.4
9250 18.1 64.6 115 1 1 4.8 2.6 | 19.0 66.2 120 9 5 10.0 5.5
9000 18.4 65.1 050 1 1 6.5 3.5 | 19.8 67.6 120 10 5 10.8 5.9
8750 18.8 65.8 025 2 1 6.3 3.4 | 20.5 68.9 120 10 5 10.6 5.8
8500 19.2 66.6 015 4 2 7.1 3.9 | 21.3 70.3 120 10 5 10.8 5.9
8250 19.7 67.5 360 5 2 8.8 4.8 | 23.3 73.9 120 10 5 19.4 10.6
8000 20.5 68.9 355 6 3 14.1 7.7 | 25.0 77.0 115 9 5 27.5 15.1
7750 21.8 71.2 350 6 3 21.0 11.5 | 26.8 80.2 115 9 5 14.0 7.7
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
06/26/2024 at 1500 MDT | 06/26/2024 at 1800 MDT
|
CAPE... +1052.8 LI... -3.7 | CAPE... +1685.0 LI... -5.9
CINH... -22.9 K Index... +24.0 | CINH... -0.5 K Index... +33.6
|
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 -85.2 280 32 17 2.6 1.4 | -65.2 -85.4 280 31 16 3.4 1.9
45000 -58.6 -73.5 285 43 22 6.7 3.7 | -58.5 -73.3 280 44 23 6.0 3.3
40000 -48.6 -55.5 280 48 25 6.9 3.8 | -49.1 -56.4 280 54 28 7.6 4.2
38000 -44.5 -48.1 280 50 26 6.9 3.8 | -44.5 -48.1 275 53 27 7.6 4.2
36000 -39.8 -39.6 275 52 27 7.5 4.1 | -39.3 -38.7 275 51 26 8.3 4.6
34000 -35.3 -31.5 275 49 25 7.5 4.1 | -34.3 -29.7 275 49 25 8.3 4.5
32000 -30.8 -23.4 275 45 23 8.2 4.5 | -29.4 -20.9 280 46 24 8.9 4.9
30000 -26.4 -15.5 275 38 20 7.5 4.1 | -24.7 -12.5 280 43 22 7.9 4.3
29000 -24.1 -11.4 270 34 18 7.5 4.1 | -22.4 -8.3 280 41 21 7.9 4.3
28000 -22.0 -7.6 270 31 16 6.8 3.7 | -20.2 -4.4 280 40 21 6.3 3.5
27000 -20.0 -4.0 265 28 14 6.9 3.8 | -18.3 -0.9 275 39 20 6.5 3.6
26000 -17.9 -0.2 265 25 13 6.9 3.8 | -16.4 2.5 270 38 20 6.5 3.6
25000 -15.9 3.4 265 22 11 6.7 3.7 | -14.5 5.9 270 38 19 6.0 3.3
24000 -13.9 7.0 265 19 10 6.6 3.6 | -13.0 8.6 260 33 17 5.3 2.9
23000 -11.9 10.6 260 17 9 6.6 3.6 | -11.0 12.2 250 28 15 5.3 2.9
22000 -9.9 14.2 260 15 8 6.4 3.5 | -9.5 14.9 240 26 13 5.8 3.2
21000 -7.6 18.3 260 14 7 6.4 3.5 | -7.8 18.0 235 24 12 5.8 3.2
20000 -5.8 21.6 260 14 7 6.5 3.6 | -6.2 20.8 235 23 12 5.9 3.2
19500 -4.8 23.4 260 14 7 7.8 4.3 | -5.3 22.5 230 22 11 6.6 3.6
19000 -3.7 25.3 250 13 7 8.4 4.6 | -4.3 24.3 230 22 11 7.5 4.1
18500 -2.5 27.5 245 13 7 8.5 4.7 | -3.2 26.2 225 21 11 7.5 4.1
18000 -1.3 29.7 240 13 7 8.0 4.4 | -2.1 28.2 225 21 11 7.7 4.2
17500 -0.0 32.0 235 13 7 8.1 4.4 | -1.0 30.2 220 21 11 7.7 4.2
17000 1.2 34.2 230 12 6 8.1 4.4 | 0.1 32.2 215 21 11 8.0 4.4
16500 2.4 36.3 225 12 6 8.1 4.4 | 1.3 34.3 210 21 11 8.4 4.6
16000 3.6 38.5 215 11 6 8.1 4.5 | 2.5 36.5 210 21 11 8.4 4.6
15500 4.8 40.6 210 11 6 8.4 4.6 | 3.7 38.7 200 20 10 7.8 4.3
15000 6.1 43.0 210 12 6 8.4 4.6 | 4.9 40.8 195 20 10 7.9 4.3
14500 7.3 45.1 205 13 7 8.5 4.7 | 6.1 43.0 190 19 10 7.9 4.4
14000 8.5 47.3 205 13 7 8.6 4.7 | 7.3 45.1 185 19 10 8.0 4.4
13500 9.7 49.5 200 14 7 8.4 4.6 | 8.4 47.1 175 20 10 7.9 4.4
13000 10.9 51.6 185 14 7 7.9 4.3 | 9.3 48.7 175 19 10 8.1 4.4
12500 11.9 53.4 175 14 7 6.1 3.4 | 10.2 50.4 175 18 9 8.6 4.7
12000 12.4 54.3 160 16 8 4.8 2.7 | 11.7 53.1 175 18 9 12.0 6.6
11750 12.7 54.9 155 16 8 4.8 2.6 | 12.5 54.5 175 18 9 9.8 5.4
11500 12.9 55.2 150 17 9 6.7 3.7 | 13.1 55.6 170 18 9 7.5 4.1
11250 13.5 56.3 150 17 9 9.3 5.1 | 13.7 56.7 170 18 9 9.6 5.3
11000 14.2 57.6 150 17 9 9.6 5.3 | 14.5 58.1 170 17 9 10.6 5.8
10750 14.9 58.8 150 17 9 9.4 5.2 | 15.3 59.5 170 17 9 11.1 6.1
10500 15.6 60.1 150 18 9 9.7 5.3 | 16.1 61.0 170 17 9 8.2 4.5
10250 16.3 61.3 150 18 9 10.1 5.5 | 16.5 61.7 170 17 9 7.7 4.2
10000 17.0 62.6 150 18 9 10.0 5.5 | 17.3 63.1 170 16 8 10.3 5.7
9750 17.8 64.0 150 18 9 10.5 5.8 | 18.0 64.4 170 16 8 9.5 5.2
9500 18.5 65.3 150 18 9 8.5 4.6 | 18.7 65.7 170 15 8 10.1 5.5
9250 19.1 66.4 150 18 9 9.2 5.1 | 20.2 68.4 170 14 7 9.7 5.3
9000 19.9 67.8 150 18 9 12.0 6.6 | 20.9 69.6 170 14 7 9.7 5.3
8750 20.8 69.4 150 18 9 11.7 6.4 | 21.6 70.9 170 13 7 9.9 5.4
8500 21.7 71.1 150 18 9 10.9 6.0 | 22.4 72.3 170 12 6 12.4 6.8
8250 22.4 72.3 150 18 9 11.1 6.1 | 23.5 74.3 170 12 6 15.8 8.7
8000 23.5 74.3 150 17 9 19.1 10.5 | 24.7 76.5 170 10 5 16.7 9.2
7750 25.3 77.5 150 16 8 28.8 15.8 | 25.9 78.6 170 8 4 16.5 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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