Soaring Guidance
Issued by NWS Pueblo, CO
Issued by NWS Pueblo, CO
752
UXUS97 KPUB 031234
SRGPUB
Soaring Forecast
National Weather Service Pueblo, Colorado
0634 MDT Wednesday, July 3, 2024
This forecast is for the Air Force Academy for Wednesday, July 3, 2024:
If the trigger temperature of 67.5 F/19.7 C is reached...then
Thermal Soaring Index....................... Excellent
Maximum rate of lift........................ 927 ft/min (4.7 m/s)
Maximum height of thermals.................. 18329 ft MSL (10719 ft AGL)
Forecast maximum temperature................... 82.0 F/28.2 C
Time of trigger temperature.................... 0915 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................. 16353 ft MSL (8742 ft AGL)
Thermal soaring outlook for Thursday 07/04..... Excellent
Wave Soaring Index............................. Not available
Remarks...
Sunrise/Sunset.................... 05:38:54 / 20:28:29 MDT
Total possible sunshine........... 14 hr 49 min 35 sec (889 min 35 sec)
Altitude of sun at 13:03:42 MDT... 73.87 degrees
Upper air data from numerical model forecast valid on 07/03/2024 at 0600 MDT
Freezing level.................. 15414 ft MSL (7804 ft AGL)
Convective condensation level... 11669 ft MSL (4059 ft AGL)
Lifted condensation level....... 14910 ft MSL (7300 ft AGL)
Lifted index.................... -8.8
K index......................... +10.3
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 -61.0 -77.8 255 38 20 3.1 1.7 M M M M M
45000 -55.3 -67.5 245 53 27 5.2 2.9 M M M M M
40000 -47.5 -53.5 235 72 37 5.0 2.8 M M M M M
38000 -44.1 -47.4 240 70 36 5.0 2.7 M M M M M
36000 -41.1 -42.0 240 68 35 5.0 2.7 M M M M M
34000 -38.2 -36.8 240 62 32 4.9 2.7 M M M M M
32000 -35.2 -31.4 235 55 28 4.7 2.6 M M M M M
30000 -31.1 -24.0 230 48 25 7.3 4.0 37.5 99.5 7.6 M M
29000 -28.9 -20.0 225 45 23 7.4 4.0 36.6 97.9 7.0 M M
28000 -26.7 -16.1 220 41 21 7.8 4.3 35.9 96.6 6.5 M M
27000 -24.2 -11.6 225 40 21 8.2 4.5 35.2 95.3 6.0 M M
26000 -21.7 -7.1 225 39 20 8.2 4.5 34.6 94.3 5.6 M M
25000 -19.3 -2.7 225 37 19 8.3 4.5 34.2 93.5 5.3 M M
24000 -16.9 1.6 225 35 18 7.9 4.4 33.5 92.3 4.8 M M
23000 -13.9 7.0 230 33 17 7.9 4.4 32.7 90.8 4.2 M M
22000 -11.5 11.3 235 31 16 7.2 4.0 32.1 89.8 3.7 M M
21000 -9.5 14.9 240 30 15 6.6 3.6 30.9 87.7 2.7 M M
20000 -7.6 18.3 245 29 15 6.7 3.7 29.9 85.8 1.8 M M
19500 -6.6 20.1 245 28 14 6.8 3.7 29.4 84.9 1.4 M M
19000 -5.7 21.7 250 28 14 5.3 2.9 28.8 83.8 0.8 M M
18500 -4.9 23.2 250 28 14 5.4 3.0 28.1 82.5 0.1 M M
18000 -4.1 24.6 255 28 14 4.9 2.7 27.4 81.2 -0.5 897 4.6
17500 -3.5 25.7 255 28 14 4.5 2.5 26.4 79.6 -1.3 862 4.4
17000 -2.8 27.0 260 27 14 4.4 2.4 25.6 78.0 -2.1 828 4.2
16500 -2.0 28.4 260 27 14 6.4 3.5 24.9 76.8 -2.8 790 4.0
16000 -1.2 29.8 265 27 14 6.3 3.5 24.3 75.7 -3.5 749 3.8
15500 -0.2 31.6 265 26 13 8.6 4.7 23.9 75.0 -4.0 706 3.6
15000 1.1 34.0 270 25 13 9.0 5.0 23.7 74.7 -4.2 652 3.3
14500 2.4 36.3 270 24 12 8.9 4.9 23.7 74.6 -4.3 598 3.0
14000 3.6 38.5 270 23 12 8.7 4.8 23.5 74.2 -4.7 548 2.8
13500 4.7 40.5 270 21 11 8.6 4.7 23.3 74.0 -5.0 499 2.5
13000 5.7 42.3 265 19 10 6.9 3.8 23.0 73.4 -5.5 454 2.3
12500 6.6 43.9 260 18 9 6.5 3.6 22.5 72.5 -6.1 413 2.1
12000 7.3 45.1 250 17 9 4.5 2.5 21.8 71.3 -6.9 377 1.9
11750 7.6 45.7 245 16 8 4.8 2.7 21.4 70.6 -7.4 361 1.8
11500 7.9 46.2 240 15 8 4.9 2.7 21.0 69.9 -7.8 344 1.7
11250 8.2 46.8 235 15 7 5.5 3.0 20.7 69.2 -8.3 328 1.7
11000 8.6 47.5 225 14 7 6.1 3.3 20.4 68.7 -8.6 309 1.6
10750 9.0 48.2 220 14 7 5.6 3.1 20.1 68.1 -9.0 290 1.5
10500 9.4 48.9 215 14 7 7.2 3.9 19.8 67.6 -9.4 271 1.4
10250 9.8 49.6 210 14 7 6.8 3.7 19.6 67.4 -9.6 249 1.3
10000 10.2 50.4 205 15 8 4.9 2.7 19.3 66.7 -10.1 231 1.2
9750 10.5 50.9 200 16 8 5.5 3.0 18.9 66.1 -10.5 214 1.1
9500 10.9 51.6 195 16 8 5.1 2.8 18.6 65.5 -10.9 196 1.0
9250 11.2 52.2 190 17 9 5.9 3.2 18.3 64.9 -11.3 178 0.9
9000 11.7 53.1 180 18 9 7.1 3.9 18.0 64.5 -11.6 157 0.8
8750 12.2 54.0 170 19 10 7.4 4.0 17.9 64.1 -11.9 135 0.7
8500 12.6 54.7 165 20 10 7.0 3.9 17.7 63.8 -12.1 113 0.6
8250 13.1 55.6 160 21 11 5.2 2.9 17.4 63.4 -12.5 93 0.5
8000 13.4 56.1 160 18 9 5.1 2.8 17.0 62.7 -12.9 76 0.4
7750 13.8 56.8 160 14 7 7.7 4.2 16.8 62.2 -13.2 55 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 * * * * * *
07/03/2024 at 0900 MDT | 07/03/2024 at 1200 MDT
|
CAPE... +1908.6 LI... -6.5 | CAPE... +1926.4 LI... -6.8
CINH... -0.2 K Index... +4.3 | CINH... -20.7 K Index... +20.0
|
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 -59.8 -75.6 260 39 20 2.8 1.5 | -60.8 -77.4 265 41 21 2.8 1.5
45000 -54.7 -66.5 255 54 28 4.7 2.6 | -55.0 -67.0 260 56 29 6.0 3.3
40000 -47.2 -53.0 240 69 35 5.3 2.9 | -45.8 -50.4 250 69 35 4.8 2.6
38000 -44.0 -47.2 240 67 34 5.3 2.9 | -42.9 -45.2 245 68 35 4.8 2.6
36000 -40.8 -41.4 240 64 33 5.4 3.0 | -40.0 -40.0 240 68 35 4.8 2.7
34000 -38.1 -36.6 235 59 30 4.4 2.4 | -37.2 -35.0 240 64 33 4.7 2.6
32000 -35.5 -31.9 235 53 27 4.4 2.4 | -34.4 -29.9 240 60 31 4.7 2.6
30000 -31.8 -25.2 235 49 25 6.7 3.7 | -31.5 -24.7 235 54 28 4.8 2.6
29000 -29.8 -21.6 230 47 24 6.7 3.7 | -30.1 -22.2 235 50 26 4.8 2.6
28000 -27.8 -18.0 230 45 23 7.3 4.0 | -28.7 -19.7 235 47 24 5.6 3.1
27000 -25.3 -13.5 230 44 23 8.4 4.6 | -26.4 -15.5 240 44 23 7.9 4.3
26000 -22.8 -9.0 235 42 22 8.4 4.6 | -24.1 -11.4 240 41 21 7.9 4.3
25000 -20.2 -4.4 235 41 21 8.5 4.6 | -21.7 -7.1 245 38 20 7.9 4.3
24000 -17.2 1.0 240 38 20 7.9 4.4 | -18.7 -1.7 250 35 18 8.1 4.5
23000 -14.8 5.4 245 36 18 8.0 4.4 | -16.3 2.7 255 32 16 8.1 4.5
22000 -12.4 9.7 250 34 18 6.7 3.7 | -13.8 7.2 260 29 15 7.6 4.2
21000 -10.8 12.6 255 29 15 5.5 3.0 | -11.7 10.9 270 29 15 7.0 3.9
20000 -9.2 15.4 270 26 13 5.6 3.0 | -9.6 14.7 275 29 15 7.1 3.9
19500 -8.3 17.1 275 25 13 5.6 3.1 | -8.6 16.5 275 30 15 7.1 3.9
19000 -7.4 18.7 280 25 13 7.4 4.1 | -7.6 18.3 280 30 15 6.6 3.6
18500 -6.3 20.7 285 26 14 7.3 4.0 | -6.6 20.1 280 30 16 6.7 3.7
18000 -5.3 22.5 290 28 14 7.0 3.9 | -5.7 21.7 280 31 16 7.2 3.9
17500 -4.3 24.3 290 30 15 6.9 3.8 | -4.6 23.7 280 32 16 7.6 4.2
17000 -3.3 26.1 290 31 16 6.9 3.8 | -3.6 25.5 280 32 17 7.8 4.3
16500 -2.2 28.0 295 32 17 7.7 4.2 | -2.5 27.5 280 31 16 8.4 4.6
16000 -1.1 30.0 295 33 17 7.6 4.2 | -1.3 29.7 275 30 15 8.5 4.6
15500 0.0 32.0 295 33 17 8.6 4.7 | -0.1 31.8 275 27 14 8.9 4.9
15000 1.3 34.3 295 32 16 8.8 4.8 | 1.2 34.2 275 24 13 9.0 4.9
14500 2.6 36.7 295 31 16 8.5 4.6 | 2.6 36.7 270 22 11 9.1 5.0
14000 3.8 38.8 295 29 15 8.1 4.5 | 3.9 39.0 265 21 11 9.1 5.0
13500 5.0 41.0 295 27 14 8.2 4.5 | 5.2 41.4 265 20 10 9.1 5.0
13000 6.3 43.3 290 25 13 8.7 4.8 | 6.6 43.9 265 18 9 9.3 5.1
12500 7.5 45.5 290 23 12 8.6 4.7 | 8.0 46.4 260 17 9 9.3 5.1
12000 8.7 47.7 290 20 10 8.6 4.7 | 9.3 48.7 260 15 8 8.7 4.8
11750 9.3 48.7 285 19 10 8.6 4.7 | 10.0 50.0 260 15 7 9.3 5.1
11500 9.8 49.6 285 17 9 8.0 4.4 | 10.8 51.4 260 14 7 11.2 6.1
11250 10.2 50.4 280 17 9 3.2 1.8 | 11.6 52.9 260 13 7 9.6 5.2
11000 10.1 50.2 275 15 8 0.1 0.0 | 12.2 54.0 255 13 7 7.9 4.3
10750 10.0 50.0 265 15 8 1.0 0.5 | 12.8 55.0 255 12 6 7.2 3.9
10500 9.9 49.8 250 15 8 1.7 0.9 | 13.4 56.1 255 12 6 11.6 6.4
10250 10.0 50.0 240 15 8 4.5 2.5 | 14.3 57.7 250 11 6 9.1 5.0
10000 10.3 50.5 225 15 8 5.8 3.2 | 14.5 58.1 250 11 6 2.6 1.4
9750 10.6 51.1 210 16 8 5.6 3.1 | 14.6 58.3 245 10 5 5.2 2.8
9500 10.9 51.6 200 18 9 5.6 3.1 | 14.8 58.6 240 10 5 2.9 1.6
9250 11.3 52.3 195 20 10 7.1 3.9 | 14.7 58.5 235 10 5 0.9 0.5
9000 11.8 53.2 190 21 11 8.8 4.8 | 14.8 58.6 220 11 6 5.5 3.0
8750 12.4 54.3 185 22 11 8.8 4.8 | 15.3 59.5 215 11 6 8.6 4.7
8500 13.0 55.4 180 23 12 8.7 4.8 | 15.8 60.4 205 12 6 7.9 4.3
8250 13.6 56.5 175 23 12 8.3 4.6 | 16.3 61.3 200 12 6 10.2 5.6
8000 14.1 57.4 170 21 11 8.9 4.9 | 17.3 63.1 195 12 6 17.8 9.8
7750 14.8 58.6 170 17 9 10.5 5.8 | 18.9 66.0 195 11 6 26.0 14.2
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
07/03/2024 at 1500 MDT | 07/03/2024 at 1800 MDT
|
CAPE... +1528.7 LI... -6.0 | CAPE... +1153.4 LI... -5.9
CINH... -18.3 K Index... +32.3 | CINH... -13.6 K Index... +25.8
|
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 -60.9 -77.6 260 45 23 3.8 2.1 | -62.0 -79.6 265 43 22 4.1 2.2
45000 -54.6 -66.3 265 58 30 4.8 2.6 | -55.0 -67.0 260 50 26 5.7 3.1
40000 -46.7 -52.1 255 68 35 5.9 3.3 | -46.1 -51.0 255 57 29 5.3 2.9
38000 -43.2 -45.8 250 66 34 5.9 3.2 | -43.0 -45.4 255 57 29 5.3 2.9
36000 -39.6 -39.3 250 65 33 6.1 3.3 | -39.8 -39.6 260 57 29 5.3 2.9
34000 -36.7 -34.1 250 61 31 4.8 2.6 | -36.5 -33.7 260 53 27 5.4 3.0
32000 -33.8 -28.8 250 57 29 4.8 2.6 | -33.3 -27.9 265 48 25 5.3 2.9
30000 -30.8 -23.4 250 52 27 5.0 2.8 | -29.5 -21.1 265 46 24 6.4 3.5
29000 -29.3 -20.7 250 50 26 5.0 2.8 | -27.6 -17.7 265 45 23 6.4 3.5
28000 -27.8 -18.0 250 48 25 5.1 2.8 | -25.7 -14.3 265 44 23 6.2 3.4
27000 -26.2 -15.2 255 46 23 5.4 2.9 | -23.9 -11.0 270 43 22 6.0 3.3
26000 -24.6 -12.3 255 43 22 5.4 3.0 | -22.1 -7.8 270 42 22 6.0 3.3
25000 -23.0 -9.4 255 41 21 5.2 2.9 | -20.3 -4.5 270 41 21 6.0 3.3
24000 -20.9 -5.6 260 39 20 7.8 4.3 | -18.5 -1.3 270 39 20 5.8 3.2
23000 -18.0 -0.4 265 38 20 7.9 4.3 | -16.8 1.8 265 37 19 5.8 3.2
22000 -15.8 3.6 265 37 19 8.8 4.8 | -15.1 4.8 260 36 18 5.8 3.2
21000 -13.0 8.6 270 34 17 9.5 5.2 | -12.4 9.7 260 32 17 7.9 4.3
20000 -10.3 13.5 270 31 16 9.6 5.3 | -10.2 13.6 265 29 15 8.1 4.5
19500 -8.9 16.0 270 30 15 9.5 5.2 | -9.1 15.6 270 28 14 8.4 4.6
19000 -7.7 18.1 270 29 15 7.6 4.1 | -7.8 18.0 270 27 14 9.5 5.2
18500 -6.6 20.1 275 28 15 7.7 4.2 | -6.4 20.5 275 26 13 9.5 5.2
18000 -5.4 22.3 275 28 14 8.8 4.8 | -5.0 23.0 275 25 13 9.5 5.2
17500 -4.0 24.8 275 27 14 9.2 5.1 | -3.5 25.7 275 25 13 9.6 5.2
17000 -2.7 27.1 275 26 14 9.3 5.1 | -2.1 28.2 280 24 13 9.6 5.2
16500 -1.2 29.8 275 26 13 9.9 5.4 | -0.7 30.7 280 24 12 9.6 5.3
16000 0.3 32.5 275 25 13 9.9 5.4 | 0.8 33.4 280 23 12 9.6 5.3
15500 1.7 35.1 275 25 13 9.7 5.3 | 2.2 36.0 285 22 12 9.6 5.2
15000 3.2 37.8 275 24 13 9.7 5.3 | 3.6 38.5 285 21 11 9.6 5.2
14500 4.6 40.3 275 24 12 9.5 5.2 | 5.0 41.0 290 20 10 9.6 5.3
14000 6.0 42.8 275 23 12 9.3 5.1 | 6.5 43.7 290 19 10 9.7 5.3
13500 7.4 45.3 275 22 11 9.3 5.1 | 7.9 46.2 295 18 9 9.4 5.2
13000 8.7 47.7 270 21 11 9.2 5.0 | 9.2 48.6 295 17 9 8.8 4.8
12500 10.0 50.0 270 20 10 8.5 4.6 | 10.5 50.9 295 15 8 8.9 4.9
12000 11.2 52.2 265 19 10 8.2 4.5 | 11.6 52.9 295 14 7 7.2 3.9
11750 11.7 53.1 265 18 9 8.5 4.7 | 12.1 53.8 290 13 7 8.5 4.7
11500 12.4 54.3 260 17 9 9.5 5.2 | 12.8 55.0 290 13 6 11.2 6.2
11250 13.0 55.4 260 17 9 8.1 4.4 | 13.6 56.5 290 12 6 8.5 4.7
11000 13.5 56.3 255 16 8 6.9 3.8 | 14.0 57.2 285 11 5 6.3 3.4
10750 14.0 57.2 250 16 8 6.4 3.5 | 14.4 57.9 280 10 5 5.4 2.9
10500 14.5 58.1 245 15 8 9.8 5.4 | 14.9 58.8 270 9 4 11.4 6.2
10250 15.3 59.5 240 14 7 10.2 5.6 | 15.9 60.6 265 8 4 12.9 7.1
10000 15.8 60.4 235 14 7 6.9 3.8 | 16.5 61.7 255 7 3 7.6 4.2
9750 16.3 61.3 225 13 7 7.9 4.3 | 17.1 62.8 240 6 3 9.3 5.1
9500 16.8 62.2 220 13 7 7.3 4.0 | 17.7 63.9 225 5 3 7.9 4.3
9250 17.3 63.1 210 13 6 6.3 3.5 | 18.2 64.8 210 5 3 6.8 3.7
9000 17.8 64.0 205 12 6 8.2 4.5 | 18.8 65.8 205 5 3 9.5 5.2
8750 18.4 65.1 195 12 6 9.9 5.4 | 19.6 67.3 200 5 3 11.2 6.2
8500 19.1 66.4 190 12 6 9.4 5.1 | 20.4 68.7 190 5 3 10.7 5.9
8250 19.8 67.6 185 12 6 10.0 5.5 | 21.1 70.0 185 5 3 9.8 5.4
8000 20.6 69.1 180 12 6 11.8 6.5 | 21.9 71.4 185 5 3 12.3 6.7
7750 21.5 70.7 180 10 5 13.8 7.6 | 23.0 73.4 180 5 2 18.3 10.0
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.
042613