Soaring Guidance
Issued by NWS Pueblo, CO
Issued by NWS Pueblo, CO
965
UXUS97 KPUB 041203
SRGPUB
Soaring Forecast
National Weather Service Pueblo, Colorado
0603 MDT Tuesday, June 4, 2024
This forecast is for the Air Force Academy for Tuesday, June 4, 2024:
If the trigger temperature of 61.5 F/16.4 C is reached...then
Thermal Soaring Index....................... Excellent
Maximum rate of lift........................ 917 ft/min (4.7 m/s)
Maximum height of thermals.................. 20553 ft MSL (12948 ft AGL)
Forecast maximum temperature................... 81.0 F/27.7 C
Time of trigger temperature.................... 0700 MDT
Time of overdevelopment........................ 1200 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................. 17829 ft MSL (10224 ft AGL)
Thermal soaring outlook for Wednesday 06/05.... Excellent
Wave Soaring Index............................. Not available
Remarks...
Sunrise/Sunset.................... 05:34:16 / 20:21:16 MDT
Total possible sunshine........... 14 hr 47 min 0 sec (887 min 0 sec)
Altitude of sun at 12:57:46 MDT... 73.57 degrees
Upper air data from numerical model forecast valid on 06/04/2024 at 0600 MDT
Freezing level.................. 13447 ft MSL (5842 ft AGL)
Convective condensation level... 13667 ft MSL (6062 ft AGL)
Lifted condensation level....... 17545 ft MSL (9941 ft AGL)
Lifted index.................... -6.0
K index......................... +18.2
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 -56.4 -69.5 310 31 16 1.2 0.6 M M M M M
45000 -55.1 -67.2 315 42 22 -0.5 -0.3 M M M M M
40000 -55.8 -68.4 320 45 23 0.6 0.4 M M M M M
38000 -52.1 -61.8 315 42 22 6.7 3.7 M M M M M
36000 -47.6 -53.7 310 39 20 6.7 3.7 M M M M M
34000 -43.5 -46.3 300 34 18 6.8 3.7 M M M M M
32000 -39.4 -38.9 285 31 16 6.8 3.7 M M M M M
30000 -35.0 -31.0 280 30 15 8.0 4.4 33.5 92.3 4.9 M M
29000 -32.6 -26.7 280 30 16 8.0 4.4 32.8 91.0 4.4 M M
28000 -30.2 -22.4 280 31 16 8.0 4.4 32.2 90.0 4.0 M M
27000 -27.8 -18.0 280 31 16 8.3 4.6 31.6 88.9 3.5 M M
26000 -25.3 -13.5 285 31 16 8.3 4.6 31.0 87.8 3.1 M M
25000 -22.8 -9.0 285 32 16 8.3 4.6 30.6 87.0 2.7 M M
24000 -20.3 -4.5 290 31 16 7.9 4.3 30.0 86.0 2.3 M M
23000 -18.0 -0.4 290 30 15 7.9 4.4 29.3 84.7 1.7 M M
22000 -15.6 3.9 290 28 14 7.9 4.4 28.7 83.7 1.2 M M
21000 -12.9 8.8 290 27 14 7.1 3.9 27.7 81.9 0.3 M M
20000 -10.8 12.6 290 26 14 7.1 3.9 26.8 80.2 -0.6 1056 5.4
19500 -9.7 14.5 290 26 13 7.0 3.9 26.4 79.4 -1.0 1010 5.1
19000 -8.7 16.3 290 26 13 6.3 3.5 26.0 78.7 -1.3 964 4.9
18500 -8.0 17.6 295 27 14 5.0 2.7 25.2 77.3 -2.1 927 4.7
18000 -7.2 19.0 300 29 15 5.1 2.8 24.4 75.9 -2.8 891 4.5
17500 -6.5 20.3 300 31 16 4.7 2.6 23.6 74.4 -3.6 855 4.3
17000 -5.9 21.4 305 33 17 4.7 2.6 22.7 72.9 -4.5 821 4.2
16500 -5.3 22.5 305 35 18 5.1 2.8 21.9 71.4 -5.3 787 4.0
16000 -4.5 23.9 310 36 19 5.5 3.0 21.2 70.1 -6.0 749 3.8
15500 -3.7 25.3 310 37 19 5.6 3.1 20.5 68.9 -6.8 711 3.6
15000 -2.9 26.8 310 38 19 6.4 3.5 19.9 67.8 -7.4 671 3.4
14500 -2.0 28.4 315 37 19 6.3 3.5 19.3 66.8 -8.0 630 3.2
14000 -1.1 30.0 315 36 18 6.8 3.7 18.8 65.8 -8.6 588 3.0
13500 -0.1 31.8 315 34 17 6.7 3.7 18.3 65.0 -9.2 544 2.8
13000 1.0 33.8 310 32 16 10.3 5.6 18.0 64.4 -9.6 497 2.5
12500 2.4 36.3 310 28 14 8.0 4.4 18.0 64.4 -9.7 440 2.2
12000 3.6 38.5 305 23 12 7.6 4.2 17.8 64.0 -10.0 389 2.0
11750 4.1 39.4 305 21 11 7.2 3.9 17.6 63.6 -10.2 366 1.9
11500 4.7 40.5 300 18 9 8.5 4.7 17.4 63.3 -10.4 342 1.7
11250 5.3 41.5 295 16 8 9.6 5.2 17.4 63.2 -10.5 314 1.6
11000 6.0 42.8 290 14 7 8.1 4.5 17.3 63.2 -10.6 287 1.5
10750 6.5 43.7 290 12 6 6.9 3.8 17.1 62.8 -10.8 264 1.3
10500 7.1 44.8 285 11 6 7.6 4.2 16.9 62.4 -11.1 241 1.2
10250 7.7 45.9 280 9 5 9.7 5.3 16.8 62.3 -11.2 215 1.1
10000 8.4 47.1 275 8 4 8.7 4.7 16.8 62.3 -11.2 185 0.9
9750 8.9 48.0 270 7 4 6.8 3.7 16.6 61.9 -11.5 162 0.8
9500 9.5 49.1 265 6 3 7.1 3.9 16.4 61.6 -11.7 139 0.7
9250 10.0 50.0 265 5 3 7.8 4.3 16.2 61.2 -11.9 116 0.6
9000 10.6 51.1 250 4 2 7.4 4.0 16.1 61.0 -12.1 91 0.5
8750 11.0 51.8 245 3 2 6.0 3.3 15.8 60.5 -12.4 70 0.4
8500 11.5 52.7 235 2 1 6.8 3.7 15.6 60.1 -12.7 48 0.2
8250 12.0 53.6 220 1 1 5.1 2.8 15.3 59.6 -13.0 27 0.1
8000 12.1 53.8 250 1 0 -0.5 -0.3 14.8 58.6 -13.6 15 0.1
7750 11.9 53.4 315 1 0 -4.7 -2.6 13.8 56.9 -14.6 14 0.1
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 * * * * * *
06/04/2024 at 0900 MDT | 06/04/2024 at 1200 MDT
|
CAPE... +19.2 LI... +1.4 | CAPE... +50.5 LI... +1.3
CINH... -0.3 K Index... +12.4 | CINH... -0.8 K Index... +13.0
|
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 -57.5 -71.5 315 33 17 0.3 0.2 | -58.2 -72.8 330 26 13 0.3 0.1
45000 -57.0 -70.6 315 48 24 0.2 0.1 | -57.6 -71.7 330 42 22 0.8 0.4
40000 -56.8 -70.2 340 54 28 3.0 1.6 | -56.0 -68.8 330 54 28 7.2 4.0
38000 -51.6 -60.9 335 59 30 7.9 4.3 | -51.4 -60.5 335 56 29 7.7 4.2
36000 -46.8 -52.2 335 63 32 7.9 4.3 | -46.8 -52.2 335 59 30 7.7 4.2
34000 -42.0 -43.6 330 66 34 8.2 4.5 | -41.9 -43.4 335 60 31 8.5 4.7
32000 -37.0 -34.6 330 69 35 8.2 4.5 | -36.1 -33.0 335 61 31 8.5 4.7
30000 -32.7 -26.9 330 64 33 6.6 3.6 | -31.5 -24.7 330 60 31 7.5 4.1
29000 -30.8 -23.4 325 59 31 6.6 3.6 | -29.3 -20.7 325 59 30 7.5 4.1
28000 -28.8 -19.8 325 55 28 6.6 3.6 | -27.1 -16.8 325 58 30 7.5 4.1
27000 -26.6 -15.9 320 50 26 7.6 4.1 | -24.9 -12.8 325 55 28 7.0 3.9
26000 -24.3 -11.7 315 47 24 7.6 4.2 | -22.8 -9.0 320 50 26 7.1 3.9
25000 -22.1 -7.8 305 43 22 7.6 4.2 | -20.7 -5.3 320 46 24 7.1 3.9
24000 -19.8 -3.6 300 40 21 7.5 4.1 | -18.6 -1.5 320 42 22 7.4 4.1
23000 -17.6 0.3 295 36 18 7.5 4.1 | -16.3 2.7 315 38 19 7.5 4.1
22000 -15.3 4.5 290 32 16 7.5 4.1 | -14.0 6.8 310 33 17 7.5 4.1
21000 -12.6 9.3 285 28 14 7.1 3.9 | -11.9 10.6 305 33 17 6.9 3.8
20000 -10.5 13.1 280 25 13 7.1 3.9 | -9.9 14.2 310 35 18 6.8 3.7
19500 -9.4 15.1 280 24 12 7.1 3.9 | -8.9 16.0 310 36 19 6.8 3.7
19000 -8.3 17.1 280 22 11 6.2 3.4 | -7.8 18.0 310 37 19 6.7 3.7
18500 -7.6 18.3 290 23 12 5.1 2.8 | -6.6 20.1 310 39 20 5.1 2.8
18000 -6.9 19.6 295 23 12 4.9 2.7 | -5.9 21.4 315 39 20 5.1 2.8
17500 -6.1 21.0 305 25 13 6.7 3.7 | -5.4 22.3 315 39 20 2.8 1.5
17000 -5.1 22.8 305 28 14 6.5 3.6 | -5.0 23.0 315 38 20 3.1 1.7
16500 -4.1 24.6 310 30 15 5.0 2.7 | -4.6 23.7 315 37 19 2.8 1.5
16000 -3.7 25.3 310 30 15 3.5 1.9 | -4.3 24.3 315 34 18 2.9 1.6
15500 -3.2 26.2 315 30 15 3.5 1.9 | -4.0 24.8 310 32 16 4.3 2.4
15000 -2.7 27.1 320 28 15 4.5 2.5 | -3.0 26.6 310 29 15 7.9 4.3
14500 -2.1 28.2 320 26 14 4.3 2.3 | -1.9 28.6 305 26 13 7.8 4.3
14000 -1.4 29.5 325 25 13 6.9 3.8 | -0.8 30.6 300 22 11 8.3 4.6
13500 -0.4 31.3 330 24 12 6.7 3.7 | 0.4 32.7 300 17 9 8.2 4.5
13000 0.6 33.1 330 23 12 8.8 4.8 | 1.6 34.9 295 14 7 9.8 5.4
12500 1.7 35.1 335 22 12 6.3 3.4 | 3.0 37.4 295 11 6 9.3 5.1
12000 2.7 36.9 335 21 11 7.4 4.1 | 4.4 39.9 300 9 5 9.1 5.0
11750 3.2 37.8 335 19 10 8.1 4.4 | 5.1 41.2 300 9 5 9.4 5.1
11500 3.8 38.8 330 17 9 8.7 4.8 | 5.8 42.4 300 9 5 10.4 5.7
11250 4.5 40.1 330 15 8 9.2 5.1 | 6.6 43.9 300 9 5 10.4 5.7
11000 5.1 41.2 325 13 7 9.1 5.0 | 7.3 45.1 305 9 4 9.2 5.1
10750 5.8 42.4 325 13 7 9.0 4.9 | 8.0 46.4 305 9 4 8.3 4.5
10500 6.5 43.7 325 13 7 9.5 5.2 | 8.6 47.5 305 9 4 9.8 5.4
10250 7.2 45.0 325 12 6 10.9 6.0 | 9.5 49.1 305 8 4 11.9 6.5
10000 8.1 46.6 325 12 6 10.3 5.7 | 10.3 50.5 305 8 4 10.3 5.6
9750 8.8 47.8 325 12 6 9.5 5.2 | 11.0 51.8 310 8 4 9.1 5.0
9500 9.5 49.1 325 12 6 9.2 5.1 | 11.7 53.1 310 8 4 8.7 4.8
9250 10.2 50.4 325 12 6 11.0 6.0 | 12.4 54.3 310 8 4 11.3 6.2
9000 11.1 52.0 325 12 6 11.1 6.1 | 13.3 55.9 310 8 4 12.1 6.6
8750 11.8 53.2 325 11 6 9.5 5.2 | 14.1 57.4 315 8 4 9.9 5.5
8500 12.5 54.5 325 11 6 9.8 5.4 | 14.9 58.8 315 8 4 10.4 5.7
8250 13.3 55.9 325 11 6 10.3 5.7 | 15.6 60.1 315 8 4 10.7 5.9
8000 14.2 57.6 325 11 6 15.7 8.6 | 16.6 61.9 315 8 4 18.5 10.1
7750 15.6 60.1 325 10 5 22.3 12.2 | 18.4 65.1 320 8 4 29.8 16.3
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
06/04/2024 at 1500 MDT | 06/04/2024 at 1800 MDT
|
CAPE... +63.2 LI... -0.3 | CAPE... +30.1 LI... +1.0
CINH... -1.1 K Index... +15.6 | CINH... -5.8 K Index... +20.1
|
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 -74.9 340 39 20 0.9 0.5 | -60.4 -76.7 350 40 21 0.6 0.3
45000 -58.0 -72.4 345 60 31 0.9 0.5 | -58.7 -73.7 350 60 31 2.6 1.4
40000 -56.1 -69.0 345 69 36 9.6 5.3 | -54.3 -65.7 345 61 31 8.3 4.5
38000 -50.9 -59.6 345 64 33 8.6 4.7 | -49.6 -57.3 340 57 29 7.8 4.3
36000 -45.8 -50.4 340 60 31 8.6 4.7 | -44.9 -48.8 335 54 28 7.8 4.3
34000 -41.0 -41.8 335 56 29 7.8 4.3 | -39.6 -39.3 330 52 27 8.0 4.4
32000 -35.7 -32.3 330 53 27 7.9 4.3 | -34.8 -30.6 325 52 27 7.8 4.3
30000 -30.9 -23.6 325 52 27 8.2 4.5 | -30.1 -22.2 325 50 26 7.8 4.3
29000 -28.5 -19.3 325 52 27 8.2 4.5 | -27.8 -18.0 330 49 25 7.8 4.3
28000 -26.0 -14.8 325 53 27 8.1 4.4 | -25.5 -13.9 330 47 24 7.6 4.2
27000 -23.9 -11.0 325 51 26 6.9 3.8 | -23.4 -10.1 330 46 24 6.6 3.6
26000 -21.9 -7.4 325 48 25 6.9 3.8 | -21.5 -6.7 335 45 23 6.6 3.6
25000 -19.8 -3.6 325 46 23 6.9 3.8 | -19.5 -3.1 335 44 23 6.6 3.6
24000 -17.8 -0.0 325 42 21 6.8 3.7 | -17.5 0.5 335 42 21 6.8 3.7
23000 -15.8 3.6 320 37 19 6.8 3.7 | -15.5 4.1 335 39 20 6.8 3.7
22000 -13.8 7.2 310 33 17 6.8 3.7 | -13.5 7.7 335 36 19 6.8 3.7
21000 -11.9 10.6 310 31 16 5.7 3.1 | -11.4 11.5 325 31 16 7.1 3.9
20000 -10.2 13.6 315 30 15 5.6 3.1 | -8.7 16.3 305 25 13 7.2 3.9
19500 -9.4 15.1 315 29 15 5.6 3.1 | -7.7 18.1 295 23 12 7.5 4.1
19000 -8.1 17.4 315 29 15 5.2 2.9 | -6.9 19.6 290 23 12 2.9 1.6
18500 -7.4 18.7 315 31 16 5.1 2.8 | -6.5 20.3 300 23 12 2.8 1.5
18000 -6.6 20.1 315 32 16 5.0 2.8 | -6.2 20.8 305 24 12 3.3 1.8
17500 -6.0 21.2 315 31 16 4.3 2.4 | -5.6 21.9 305 23 12 4.9 2.7
17000 -5.5 22.1 310 29 15 4.3 2.4 | -4.9 23.2 300 23 12 4.7 2.6
16500 -4.8 23.4 305 26 13 7.1 3.9 | -4.1 24.6 295 21 11 7.7 4.2
16000 -3.8 25.2 300 22 11 7.6 4.2 | -3.0 26.6 290 19 10 7.9 4.3
15500 -2.8 27.0 290 19 10 8.5 4.6 | -2.0 28.4 285 17 9 8.4 4.6
15000 -1.4 29.5 285 16 8 9.2 5.1 | -0.7 30.7 280 15 8 8.7 4.8
14500 -0.1 31.8 280 13 7 9.4 5.1 | 0.6 33.1 275 14 7 8.7 4.8
14000 1.4 34.5 280 12 6 10.2 5.6 | 1.8 35.2 275 12 6 8.7 4.8
13500 2.8 37.0 285 11 6 10.1 5.5 | 3.1 37.6 280 11 6 8.6 4.7
13000 4.4 39.9 285 11 5 10.0 5.5 | 4.5 40.1 285 9 5 9.3 5.1
12500 5.7 42.3 290 10 5 9.0 4.9 | 5.8 42.4 295 8 4 8.9 4.9
12000 7.1 44.8 295 9 5 8.9 4.9 | 7.1 44.8 315 7 3 8.7 4.7
11750 7.8 46.0 295 9 5 9.5 5.2 | 7.7 45.9 325 7 4 8.9 4.9
11500 8.5 47.3 295 9 5 10.9 6.0 | 8.4 47.1 335 7 4 9.7 5.3
11250 9.3 48.7 295 9 5 10.6 5.8 | 9.2 48.6 345 8 4 9.6 5.3
11000 10.1 50.2 300 9 5 8.9 4.9 | 9.9 49.8 350 8 4 9.1 5.0
10750 10.7 51.3 300 9 5 8.1 4.4 | 10.5 50.9 350 8 4 8.7 4.8
10500 11.3 52.3 300 9 4 9.7 5.3 | 11.2 52.2 355 9 5 10.2 5.6
10250 12.2 54.0 305 9 4 11.5 6.3 | 12.0 53.6 355 9 5 11.4 6.2
10000 13.0 55.4 305 8 4 10.2 5.6 | 12.8 55.0 355 9 5 9.8 5.4
9750 13.7 56.7 305 8 4 9.7 5.3 | 13.5 56.3 360 10 5 9.4 5.2
9500 14.4 57.9 305 8 4 9.3 5.1 | 14.2 57.6 360 10 5 9.2 5.0
9250 15.1 59.2 310 8 4 11.4 6.3 | 15.0 59.0 360 10 5 10.6 5.8
9000 16.1 61.0 310 8 4 11.5 6.3 | 15.8 60.4 360 10 5 10.8 5.9
8750 16.8 62.2 310 8 4 9.4 5.2 | 16.5 61.7 360 10 5 9.5 5.2
8500 17.5 63.5 315 8 4 9.6 5.3 | 17.3 63.1 005 10 5 9.7 5.3
8250 18.2 64.8 315 8 4 10.7 5.9 | 18.0 64.4 005 10 5 10.2 5.6
8000 19.3 66.7 315 8 4 18.3 10.0 | 18.8 65.8 005 10 5 13.7 7.5
7750 20.9 69.6 320 7 4 26.7 14.7 | 20.0 68.0 005 10 5 17.6 9.7
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
________________________________________________________________________________
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