Soaring Guidance
Issued by NWS Pueblo, CO
Issued by NWS Pueblo, CO
652
UXUS97 KPUB 021223
SRGPUB
Soaring Forecast
National Weather Service Pueblo, Colorado
0623 MDT Tuesday, July 2, 2024
This forecast is for the Air Force Academy for Tuesday, July 2, 2024:
If the trigger temperature of 64.4 F/18.0 C is reached...then
Thermal Soaring Index....................... Good
Maximum rate of lift........................ 538 ft/min (2.7 m/s)
Maximum height of thermals.................. 17079 ft MSL (9455 ft AGL)
Forecast maximum temperature................... 81.0 F/27.7 C
Time of trigger temperature.................... 0815 MDT
Time of overdevelopment........................ 1200 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................. 14623 ft MSL (7000 ft AGL)
Thermal soaring outlook for Wednesday 07/03.... Good
Wave Soaring Index............................. Not available
Remarks...
Sunrise/Sunset.................... 05:38:23 / 20:28:39 MDT
Total possible sunshine........... 14 hr 50 min 16 sec (890 min 16 sec)
Altitude of sun at 13:03:31 MDT... 73.95 degrees
Upper air data from numerical model forecast valid on 07/02/2024 at 0600 MDT
Freezing level.................. 16187 ft MSL (8563 ft AGL)
Convective condensation level... 10993 ft MSL (3369 ft AGL)
Lifted condensation level....... 15297 ft MSL (7674 ft AGL)
Lifted index.................... -4.1
K index......................... +28.8
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 -61.9 -79.4 270 33 17 3.4 1.9 M M M M M
45000 -56.0 -68.8 260 44 23 5.0 2.7 M M M M M
40000 -47.9 -54.2 250 54 28 5.8 3.2 M M M M M
38000 -44.4 -47.9 250 52 27 5.8 3.2 M M M M M
36000 -40.9 -41.6 250 51 26 6.2 3.4 M M M M M
34000 -36.3 -33.3 255 44 23 7.7 4.2 M M M M M
32000 -31.7 -25.1 260 38 20 7.5 4.1 M M M M M
30000 -27.2 -17.0 260 37 19 7.5 4.1 42.2 108.0 11.6 M M
29000 -25.0 -13.0 260 37 19 7.5 4.1 41.4 106.6 11.1 M M
28000 -22.7 -8.9 260 37 19 7.4 4.1 40.8 105.4 10.6 M M
27000 -20.6 -5.1 260 38 19 7.3 4.0 39.7 103.5 9.9 M M
26000 -18.4 -1.1 260 38 20 7.4 4.0 38.8 101.9 9.2 M M
25000 -15.7 3.7 260 39 20 7.2 4.0 37.9 100.1 8.5 M M
24000 -13.7 7.3 255 40 21 6.8 3.7 36.7 98.1 7.6 M M
23000 -11.8 10.8 255 41 21 6.8 3.7 35.6 96.2 6.7 M M
22000 -9.8 14.4 255 43 22 6.6 3.6 34.7 94.5 5.9 M M
21000 -8.0 17.6 255 43 22 6.1 3.3 33.4 92.1 4.7 M M
20000 -6.3 20.7 255 42 22 6.1 3.3 32.1 89.8 3.6 M M
19500 -5.4 22.3 255 42 22 6.1 3.4 31.5 88.7 3.0 M M
19000 -4.6 23.7 250 42 22 5.8 3.2 30.9 87.6 2.4 M M
18500 -3.7 25.3 250 41 21 5.8 3.2 30.2 86.4 1.8 M M
18000 -2.9 26.8 250 41 21 5.8 3.2 29.6 85.2 1.2 M M
17500 -2.1 28.2 250 39 20 5.7 3.1 28.9 84.0 0.5 M M
17000 -1.3 29.7 245 38 19 5.7 3.2 28.2 82.8 -0.1 731 3.7
16500 -0.5 31.1 245 36 19 5.5 3.0 27.5 81.6 -0.8 693 3.5
16000 0.3 32.5 240 34 18 5.5 3.0 26.8 80.3 -1.5 655 3.3
15500 1.1 34.0 235 32 16 6.3 3.5 26.1 79.1 -2.2 617 3.1
15000 2.1 35.8 235 30 15 7.1 3.9 25.7 78.3 -2.6 572 2.9
14500 3.1 37.6 230 27 14 6.9 3.8 25.3 77.6 -3.1 526 2.7
14000 3.8 38.8 225 25 13 4.3 2.4 24.6 76.3 -3.8 489 2.5
13500 4.5 40.1 220 22 11 4.6 2.5 23.7 74.7 -4.7 456 2.3
13000 5.1 41.2 210 18 9 3.9 2.1 22.9 73.2 -5.6 423 2.1
12500 5.5 41.9 200 15 8 2.9 1.6 21.9 71.3 -6.6 394 2.0
12000 5.9 42.6 195 13 7 1.5 0.8 20.7 69.3 -7.7 369 1.9
11750 6.0 42.8 190 11 6 1.4 0.8 20.1 68.1 -8.3 358 1.8
11500 6.1 43.0 185 9 5 2.7 1.5 19.4 67.0 -9.0 346 1.8
11250 6.4 43.5 185 8 4 3.3 1.8 18.9 66.1 -9.5 332 1.7
11000 6.6 43.9 180 7 3 2.5 1.3 18.4 65.1 -10.0 318 1.6
10750 6.8 44.2 180 5 2 2.2 1.2 17.8 64.1 -10.6 305 1.6
10500 6.9 44.4 175 2 1 2.7 1.5 17.2 63.0 -11.2 292 1.5
10250 7.2 45.0 130 1 0 5.3 2.9 16.8 62.2 -11.6 277 1.4
10000 7.7 45.9 035 1 0 6.6 3.6 16.5 61.7 -12.0 256 1.3
9750 8.1 46.6 350 2 1 6.2 3.4 16.3 61.3 -12.3 235 1.2
9500 8.5 47.3 340 4 2 6.3 3.4 16.0 60.8 -12.6 215 1.1
9250 9.0 48.2 340 5 3 6.7 3.7 15.7 60.3 -12.9 194 1.0
9000 9.4 48.9 330 7 4 7.3 4.0 15.5 60.0 -13.2 173 0.9
8750 9.9 49.8 330 8 4 7.3 4.0 15.3 59.6 -13.5 150 0.8
8500 10.4 50.7 330 9 5 7.2 3.9 15.2 59.3 -13.7 128 0.7
8250 10.9 51.6 330 10 5 7.8 4.3 15.0 59.0 -14.0 106 0.5
8000 11.5 52.7 330 10 5 9.1 5.0 14.9 58.8 -14.2 81 0.4
7750 12.2 54.0 330 9 4 9.2 5.0 14.9 58.7 -14.3 54 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 * * * * * *
07/02/2024 at 0900 MDT | 07/02/2024 at 1200 MDT
|
CAPE... +819.8 LI... -3.8 | CAPE... +802.5 LI... -2.6
CINH... -9.3 K Index... +27.8 | CINH... 0.0 K Index... +23.5
|
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 -61.7 -79.1 270 31 16 3.5 1.9 | -61.5 -78.7 250 27 14 3.0 1.6
45000 -54.9 -66.8 265 41 21 5.6 3.1 | -55.6 -68.1 250 37 19 5.8 3.2
40000 -46.6 -51.9 250 53 27 5.1 2.8 | -46.7 -52.1 245 54 28 5.0 2.7
38000 -43.6 -46.5 245 58 30 5.1 2.8 | -43.7 -46.7 245 58 30 5.0 2.7
36000 -40.5 -40.9 240 62 32 4.9 2.7 | -40.7 -41.3 240 63 32 5.2 2.9
34000 -36.7 -34.1 235 61 31 6.6 3.6 | -36.9 -34.4 245 61 31 6.5 3.6
32000 -32.2 -26.0 230 58 30 7.0 3.8 | -33.0 -27.4 245 59 30 6.5 3.5
30000 -28.3 -18.9 240 51 26 6.4 3.5 | -29.0 -20.2 245 54 28 6.6 3.6
29000 -26.4 -15.5 245 48 25 6.4 3.5 | -27.0 -16.6 250 52 27 6.6 3.6
28000 -24.4 -11.9 255 46 23 7.6 4.2 | -25.0 -13.0 250 49 25 7.7 4.2
27000 -22.0 -7.6 255 44 23 8.1 4.4 | -22.4 -8.3 250 47 24 8.8 4.8
26000 -19.6 -3.3 250 43 22 8.1 4.4 | -19.7 -3.5 255 45 23 8.8 4.8
25000 -17.2 1.0 250 42 22 8.1 4.5 | -17.1 1.2 255 42 22 8.9 4.9
24000 -15.0 5.0 250 42 22 7.3 4.0 | -14.1 6.6 255 43 22 7.7 4.2
23000 -12.8 9.0 250 43 22 7.3 4.0 | -11.8 10.8 255 45 23 7.7 4.2
22000 -10.6 12.9 250 44 23 7.3 4.0 | -9.4 15.1 255 46 24 6.2 3.4
21000 -9.1 15.6 250 42 22 4.6 2.5 | -8.1 17.4 260 45 23 4.5 2.5
20000 -7.8 18.0 255 40 21 5.2 2.8 | -6.8 19.8 260 45 23 4.5 2.5
19500 -6.8 19.8 260 38 20 6.0 3.3 | -6.1 21.0 260 44 23 4.9 2.7
19000 -6.0 21.2 260 37 19 6.5 3.6 | -5.7 21.7 265 44 23 1.7 0.9
18500 -5.1 22.8 260 35 18 6.5 3.6 | -5.4 22.3 265 44 23 2.4 1.3
18000 -4.2 24.4 265 34 17 6.5 3.6 | -5.2 22.6 270 45 23 4.4 2.4
17500 -3.3 26.1 270 32 17 6.4 3.5 | -4.3 24.3 270 45 23 6.3 3.4
17000 -2.3 27.9 275 31 16 6.4 3.5 | -3.5 25.7 270 45 23 6.4 3.5
16500 -1.4 29.5 275 30 16 6.4 3.5 | -2.6 27.3 270 43 22 7.1 3.9
16000 -0.5 31.1 280 29 15 6.4 3.5 | -1.6 29.1 270 41 21 7.2 3.9
15500 0.5 32.9 280 29 15 7.0 3.8 | -0.6 30.9 270 39 20 7.5 4.1
15000 1.5 34.7 285 27 14 7.1 3.9 | 0.4 32.7 270 34 18 7.6 4.2
14500 2.5 36.5 290 26 14 7.2 3.9 | 1.4 34.5 265 30 15 7.8 4.3
14000 3.5 38.3 290 25 13 7.2 4.0 | 2.6 36.7 265 25 13 8.1 4.4
13500 4.6 40.3 295 23 12 7.4 4.1 | 3.7 38.7 265 21 11 8.2 4.5
13000 5.7 42.3 295 21 11 8.7 4.8 | 4.8 40.6 265 16 8 8.2 4.5
12500 6.9 44.4 295 19 10 7.8 4.3 | 6.0 42.8 265 13 6 8.4 4.6
12000 7.9 46.2 290 17 9 6.7 3.7 | 7.2 45.0 270 10 5 8.2 4.5
11750 8.3 46.9 285 17 9 6.8 3.7 | 7.8 46.0 275 8 4 8.8 4.8
11500 8.8 47.8 280 16 8 6.7 3.7 | 8.5 47.3 280 7 4 11.2 6.1
11250 9.2 48.6 275 16 8 5.8 3.2 | 9.3 48.7 285 6 3 10.2 5.6
11000 9.6 49.3 275 16 8 5.3 2.9 | 10.0 50.0 285 6 3 8.6 4.7
10750 9.9 49.8 270 16 8 4.7 2.6 | 10.6 51.1 290 6 3 8.1 4.5
10500 10.3 50.5 265 15 8 7.3 4.0 | 11.3 52.3 295 5 3 11.2 6.2
10250 10.8 51.4 265 16 8 7.6 4.2 | 12.2 54.0 300 5 3 12.3 6.8
10000 11.2 52.2 260 15 8 4.7 2.6 | 13.0 55.4 300 5 3 9.6 5.2
9750 11.5 52.7 260 15 8 5.0 2.8 | 13.7 56.7 305 5 3 9.9 5.4
9500 11.9 53.4 260 14 7 5.1 2.8 | 14.5 58.1 305 5 3 10.1 5.6
9250 12.2 54.0 255 13 7 4.6 2.5 | 15.2 59.4 310 5 3 8.8 4.8
9000 12.6 54.7 260 11 6 7.0 3.9 | 15.8 60.4 310 5 3 9.2 5.1
8750 13.2 55.8 260 9 5 9.3 5.1 | 16.6 61.9 315 5 2 11.1 6.1
8500 13.8 56.8 260 7 4 8.6 4.7 | 17.4 63.3 320 5 2 10.5 5.8
8250 14.4 57.9 255 6 3 9.1 5.0 | 18.2 64.8 320 5 2 10.7 5.9
8000 15.2 59.4 260 5 2 14.0 7.7 | 19.1 66.4 325 5 2 15.4 8.4
7750 16.5 61.7 260 4 2 20.9 11.5 | 20.5 68.9 330 4 2 22.7 12.4
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
07/02/2024 at 1500 MDT | 07/02/2024 at 1800 MDT
|
CAPE... +587.4 LI... -3.7 | CAPE... +875.1 LI... -4.0
CINH... -5.3 K Index... +31.0 | CINH... -9.5 K Index... +29.8
|
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 -61.3 -78.3 245 28 14 2.4 1.3 | -61.4 -78.5 235 33 17 2.7 1.5
45000 -55.2 -67.4 240 39 20 6.5 3.6 | -55.0 -67.0 235 45 23 6.5 3.6
40000 -45.9 -50.6 250 54 28 4.6 2.5 | -45.7 -50.3 250 55 28 4.4 2.4
38000 -43.2 -45.8 245 61 31 4.6 2.5 | -43.1 -45.6 250 61 32 4.4 2.4
36000 -40.4 -40.7 245 67 34 4.5 2.4 | -40.5 -40.9 250 68 35 4.3 2.4
34000 -37.2 -35.0 245 66 34 5.6 3.1 | -37.2 -35.0 255 68 35 5.1 2.8
32000 -33.4 -28.1 250 64 33 5.6 3.1 | -34.1 -29.4 255 66 34 4.9 2.7
30000 -29.6 -21.3 255 58 30 6.5 3.6 | -30.4 -22.7 260 60 31 6.4 3.5
29000 -27.6 -17.7 255 55 28 6.5 3.6 | -28.5 -19.3 260 56 29 6.4 3.5
28000 -25.7 -14.3 260 52 27 8.1 4.4 | -26.5 -15.7 265 53 28 8.2 4.5
27000 -23.0 -9.4 260 50 26 8.7 4.8 | -23.9 -11.0 265 51 26 9.0 4.9
26000 -20.4 -4.7 260 48 25 8.7 4.8 | -21.2 -6.2 270 49 25 9.0 4.9
25000 -17.8 -0.0 260 47 24 8.7 4.8 | -18.5 -1.3 270 47 24 9.0 4.9
24000 -15.4 4.3 260 44 23 7.9 4.3 | -16.1 3.0 270 43 22 7.9 4.3
23000 -13.1 8.4 260 42 21 7.9 4.3 | -13.7 7.3 270 40 20 7.9 4.3
22000 -10.7 12.7 260 39 20 7.8 4.3 | -11.3 11.7 270 36 18 7.7 4.2
21000 -9.6 14.7 265 40 21 3.0 1.6 | -9.9 14.2 270 35 18 4.2 2.3
20000 -8.5 16.7 270 42 22 3.3 1.8 | -8.4 16.9 270 34 18 4.4 2.4
19500 -8.1 17.4 270 43 22 3.6 2.0 | -7.8 18.0 270 34 18 4.5 2.5
19000 -7.5 18.5 270 41 21 5.5 3.0 | -7.1 19.2 265 32 17 5.4 3.0
18500 -6.8 19.8 265 38 20 5.6 3.1 | -6.4 20.5 260 30 15 5.7 3.1
18000 -6.1 21.0 265 35 18 7.6 4.2 | -5.6 21.9 255 28 14 7.7 4.2
17500 -4.9 23.2 265 32 17 8.4 4.6 | -4.5 23.9 255 26 14 8.2 4.5
17000 -3.7 25.3 260 29 15 8.5 4.7 | -3.3 26.1 255 25 13 8.3 4.6
16500 -2.5 27.5 260 26 13 7.9 4.4 | -2.1 28.2 255 23 12 8.1 4.4
16000 -1.4 29.5 265 23 12 8.0 4.4 | -1.0 30.2 255 21 11 8.1 4.4
15500 -0.2 31.6 265 20 11 8.5 4.7 | 0.2 32.4 255 19 10 8.2 4.5
15000 1.0 33.8 265 18 9 8.6 4.7 | 1.3 34.3 255 16 8 8.3 4.5
14500 2.3 36.1 265 15 8 8.6 4.7 | 2.5 36.5 255 13 7 8.7 4.8
14000 3.5 38.3 265 13 7 8.7 4.8 | 3.8 38.8 250 10 5 9.0 4.9
13500 4.8 40.6 265 10 5 8.8 4.8 | 5.1 41.2 240 7 4 9.0 4.9
13000 6.0 42.8 265 7 3 8.8 4.8 | 6.3 43.3 215 5 2 8.7 4.8
12500 7.2 45.0 260 5 3 8.1 4.4 | 7.6 45.7 190 4 2 8.2 4.5
12000 8.5 47.3 260 4 2 9.7 5.3 | 8.7 47.7 170 4 2 7.0 3.9
11750 9.2 48.6 255 3 2 9.6 5.2 | 9.2 48.6 160 5 2 8.0 4.4
11500 9.9 49.8 255 2 1 9.8 5.4 | 9.8 49.6 155 5 3 10.0 5.5
11250 10.6 51.1 250 2 1 8.8 4.8 | 10.5 50.9 150 5 3 8.5 4.6
11000 11.2 52.2 245 1 1 8.2 4.5 | 11.1 52.0 145 5 3 7.1 3.9
10750 11.8 53.2 240 1 1 7.5 4.1 | 11.6 52.9 140 6 3 6.4 3.5
10500 12.5 54.5 230 1 0 10.9 6.0 | 12.1 53.8 135 6 3 10.5 5.7
10250 13.4 56.1 175 1 0 11.7 6.4 | 13.0 55.4 135 7 3 11.7 6.4
10000 14.1 57.4 140 1 0 8.7 4.8 | 13.7 56.7 135 7 4 8.3 4.6
9750 14.7 58.5 120 1 1 9.7 5.3 | 14.3 57.7 130 7 4 9.6 5.3
9500 15.4 59.7 115 1 1 8.8 4.8 | 15.0 59.0 130 7 4 7.9 4.3
9250 16.1 61.0 110 2 1 8.5 4.7 | 15.5 59.9 130 7 4 7.7 4.2
9000 16.7 62.1 105 2 1 9.8 5.4 | 16.2 61.2 130 8 4 10.1 5.5
8750 17.5 63.5 105 2 1 10.3 5.7 | 17.0 62.6 130 8 4 10.7 5.9
8500 18.2 64.8 105 3 1 10.1 5.6 | 17.7 63.9 125 8 4 10.3 5.7
8250 19.0 66.2 100 3 2 10.6 5.8 | 18.5 65.3 125 8 4 10.1 5.5
8000 19.9 67.8 100 3 2 12.8 7.0 | 19.3 66.7 125 8 4 13.4 7.4
7750 20.9 69.6 095 4 2 15.6 8.5 | 20.5 68.9 125 7 4 18.8 10.3
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
________________________________________________________________________________
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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