Soaring Guidance
Issued by NWS Pueblo, CO
Issued by NWS Pueblo, CO
517
UXUS97 KPUB 071231
SRGPUB
Soaring Forecast
National Weather Service Pueblo, Colorado
0631 MDT Tuesday, May 7, 2024
This forecast is for the Air Force Academy for Tuesday, May 7, 2024:
If the trigger temperature of 44.2 F/6.8 C is reached...then
Thermal Soaring Index....................... Good
Maximum rate of lift........................ 1216 ft/min (6.2 m/s)
Maximum height of thermals.................. 20875 ft MSL (13288 ft AGL)
Forecast maximum temperature................... 60.0 F/16.0 C
Time of trigger temperature.................... 0830 MDT
Time of overdevelopment........................ None
Middle/high clouds during soaring window....... None
Surface winds during soaring window............ Between 20 mph and 30 mph
Height of the -3 thermal index................. 18341 ft MSL (10755 ft AGL)
Thermal soaring outlook for Wednesday 05/08.... Good
Wave Soaring Index............................. Not available
Remarks...
Sunrise/Sunset.................... 05:53:27 / 19:58:08 MDT
Total possible sunshine........... 14 hr 4 min 41 sec (844 min 41 sec)
Altitude of sun at 12:55:48 MDT... 68.11 degrees
Upper air data from numerical model forecast valid on 05/07/2024 at 0600 MDT
Freezing level.................. 8994 ft MSL (1407 ft AGL)
Convective condensation level... 14862 ft MSL (7275 ft AGL)
Lifted condensation level....... 17656 ft MSL (10069 ft AGL)
Lifted index.................... -0.9
K index......................... +3.9
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 -52.9 -63.2 250 42 22 2.5 1.4 M M M M M
45000 -49.1 -56.4 250 66 34 1.3 0.7 M M M M M
40000 -50.8 -59.4 255 57 29 -1.2 -0.7 M M M M M
38000 -50.6 -59.1 260 62 32 2.3 1.3 M M M M M
36000 -49.3 -56.7 270 80 41 2.3 1.3 M M M M M
34000 -47.8 -54.0 275 98 50 3.3 1.8 M M M M M
32000 -45.5 -49.9 275 97 50 3.8 2.1 M M M M M
30000 -43.2 -45.8 280 96 49 4.8 2.7 26.5 79.7 8.4 M M
29000 -41.6 -42.9 280 95 49 5.5 3.0 24.7 76.4 7.1 M M
28000 -39.9 -39.8 280 94 48 5.5 3.0 23.0 73.4 5.9 M M
27000 -38.2 -36.8 280 93 48 5.6 3.1 21.5 70.7 4.8 M M
26000 -36.3 -33.3 280 92 47 7.1 3.9 20.3 68.5 3.8 M M
25000 -34.2 -29.6 285 90 46 7.2 3.9 19.2 66.6 3.0 M M
24000 -32.0 -25.6 285 88 45 7.2 3.9 18.4 65.1 2.3 M M
23000 -29.9 -21.8 285 84 43 7.3 4.0 17.5 63.5 1.6 M M
22000 -27.7 -17.9 285 76 39 7.3 4.0 16.6 61.8 0.8 M M
21000 -24.9 -12.8 290 68 35 7.2 3.9 15.6 60.1 0.0 M M
20000 -23.1 -9.6 285 65 33 5.9 3.2 14.3 57.7 -1.2 1133 5.8
19500 -22.2 -8.0 285 64 33 5.9 3.2 13.6 56.5 -1.8 1092 5.5
19000 -21.3 -6.3 285 62 32 5.9 3.2 13.0 55.3 -2.3 1051 5.3
18500 -20.4 -4.7 285 61 32 5.9 3.2 12.3 54.2 -2.9 1010 5.1
18000 -19.6 -3.3 285 62 32 5.8 3.2 11.7 53.0 -3.5 970 4.9
17500 -18.7 -1.7 285 64 33 5.8 3.2 11.0 51.8 -4.1 929 4.7
17000 -17.9 -0.2 285 66 34 6.6 3.6 10.4 50.7 -4.8 888 4.5
16500 -16.8 1.8 280 65 33 7.0 3.9 9.9 49.9 -5.2 842 4.3
16000 -15.8 3.6 280 64 33 7.3 4.0 9.5 49.1 -5.7 797 4.0
15500 -14.6 5.7 280 61 32 8.3 4.5 9.2 48.5 -6.0 747 3.8
15000 -13.4 7.9 275 59 30 8.2 4.5 8.9 48.1 -6.3 695 3.5
14500 -12.1 10.2 275 56 29 9.3 5.1 8.8 47.8 -6.5 642 3.3
14000 -10.8 12.6 275 52 27 9.2 5.0 8.7 47.6 -6.7 587 3.0
13500 -9.4 15.1 275 50 26 9.4 5.2 8.6 47.5 -6.8 531 2.7
13000 -8.0 17.6 275 48 25 10.4 5.7 8.5 47.4 -6.9 475 2.4
12500 -7.1 19.2 275 47 24 4.0 2.2 8.0 46.3 -7.5 433 2.2
12000 -6.1 21.0 280 46 24 6.6 3.6 7.5 45.5 -8.0 388 2.0
11750 -5.6 21.9 280 45 23 7.1 3.9 7.3 45.1 -8.2 365 1.9
11500 -5.1 22.8 280 45 23 6.7 3.7 7.1 44.7 -8.5 342 1.7
11250 -4.6 23.7 285 45 23 6.2 3.4 6.8 44.2 -8.8 321 1.6
11000 -4.2 24.4 285 44 23 6.2 3.4 6.5 43.7 -9.1 300 1.5
10750 -3.7 25.3 285 44 23 6.2 3.4 6.2 43.2 -9.4 279 1.4
10500 -3.3 26.1 285 43 22 5.9 3.2 6.0 42.7 -9.7 258 1.3
10250 -2.8 27.0 285 41 21 6.8 3.7 5.7 42.2 -10.0 237 1.2
10000 -2.3 27.9 280 40 20 7.7 4.2 5.5 41.9 -10.2 214 1.1
9750 -1.7 28.9 280 38 20 7.2 3.9 5.3 41.6 -10.4 190 1.0
9500 -1.2 29.8 280 36 19 6.5 3.6 5.1 41.2 -10.7 167 0.8
9250 -0.7 30.7 280 35 18 6.8 3.7 4.9 40.7 -11.0 145 0.7
9000 -0.2 31.6 275 33 17 8.2 4.5 4.7 40.4 -11.2 121 0.6
8750 0.4 32.7 275 31 16 7.7 4.2 4.6 40.2 -11.3 95 0.5
8500 0.9 33.6 275 29 15 6.5 3.6 4.3 39.8 -11.6 73 0.4
8250 1.4 34.5 270 27 14 7.2 3.9 4.1 39.4 -11.8 50 0.3
8000 2.0 35.6 270 24 12 6.5 3.6 3.9 39.1 -12.1 27 0.1
7750 2.2 36.0 270 18 9 -1.3 -0.7 3.5 38.2 -12.6 12 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 * * * * * *
05/07/2024 at 0900 MDT | 05/07/2024 at 1200 MDT
|
CAPE... +2.8 LI... +0.7 | CAPE... +90.9 LI... -0.4
CINH... -24.8 K Index... +10.3 | CINH... 0.0 K Index... +12.0
|
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 -53.6 -64.5 250 37 19 1.6 0.9 | -52.8 -63.0 240 32 16 1.0 0.6
45000 -51.1 -60.0 245 63 32 1.3 0.7 | -51.3 -60.3 250 60 31 0.9 0.5
40000 -49.9 -57.8 265 61 31 0.8 0.4 | -50.1 -58.2 260 64 33 0.8 0.4
38000 -49.0 -56.2 270 65 34 1.9 1.1 | -49.2 -56.6 265 71 37 2.3 1.3
36000 -47.9 -54.2 270 75 39 1.9 1.1 | -47.8 -54.0 265 85 44 2.3 1.3
34000 -46.6 -51.9 270 85 44 3.6 2.0 | -46.3 -51.3 270 99 51 3.5 1.9
32000 -44.0 -47.2 270 96 50 4.3 2.4 | -43.9 -47.0 265 108 56 4.0 2.2
30000 -41.4 -42.5 270 108 55 5.6 3.1 | -41.5 -42.7 265 117 60 5.2 2.8
29000 -39.5 -39.1 270 110 56 6.4 3.5 | -39.7 -39.5 265 116 60 6.0 3.3
28000 -37.6 -35.7 270 111 57 6.4 3.5 | -37.9 -36.2 265 114 59 6.0 3.3
27000 -35.7 -32.3 270 113 58 6.4 3.5 | -36.1 -33.0 265 113 58 6.0 3.3
26000 -34.0 -29.2 270 111 57 4.7 2.6 | -34.4 -29.9 265 111 57 5.7 3.1
25000 -32.6 -26.7 275 106 55 4.6 2.5 | -32.7 -26.9 265 108 55 5.7 3.1
24000 -30.9 -23.6 275 100 51 4.6 2.5 | -30.5 -22.9 270 104 54 5.7 3.2
23000 -29.7 -21.5 275 92 47 3.6 2.0 | -29.1 -20.4 270 94 49 4.1 2.3
22000 -28.7 -19.7 275 83 42 3.6 2.0 | -27.9 -18.2 265 80 41 4.1 2.3
21000 -27.6 -17.7 275 73 38 3.7 2.0 | -26.7 -16.1 265 65 34 4.2 2.3
20000 -25.4 -13.7 270 61 31 8.6 4.7 | -24.7 -12.5 265 60 31 7.4 4.0
19500 -24.1 -11.4 270 54 28 8.5 4.7 | -23.6 -10.5 265 58 30 7.3 4.0
19000 -22.9 -9.2 265 48 25 8.6 4.7 | -22.5 -8.5 260 57 29 7.4 4.0
18500 -21.6 -6.9 265 42 22 8.6 4.7 | -21.4 -6.5 260 55 28 7.4 4.1
18000 -20.4 -4.7 260 40 20 7.9 4.3 | -20.3 -4.5 260 54 28 7.4 4.1
17500 -19.2 -2.6 260 41 21 7.9 4.4 | -19.3 -2.7 260 53 27 7.5 4.1
17000 -18.0 -0.4 260 42 22 7.5 4.1 | -18.2 -0.8 260 52 27 7.7 4.3
16500 -17.0 1.4 260 43 22 7.3 4.0 | -17.0 1.4 260 49 25 7.9 4.4
16000 -15.9 3.4 265 43 22 7.3 4.0 | -15.8 3.6 265 47 24 7.8 4.3
15500 -14.8 5.4 265 42 21 7.2 4.0 | -14.7 5.5 265 46 24 7.0 3.9
15000 -13.7 7.3 265 39 20 7.2 4.0 | -13.7 7.3 270 46 24 7.0 3.9
14500 -12.7 9.1 270 38 20 7.0 3.8 | -12.6 9.3 270 45 23 7.6 4.2
14000 -11.6 11.1 275 38 19 6.9 3.8 | -11.5 11.3 270 42 22 7.4 4.1
13500 -10.5 13.1 275 38 19 9.0 4.9 | -10.2 13.6 270 40 21 10.3 5.6
13000 -9.1 15.6 280 37 19 10.2 5.6 | -8.7 16.3 270 39 20 12.2 6.7
12500 -8.4 16.9 280 38 19 3.2 1.7 | -7.9 17.8 270 37 19 2.4 1.3
12000 -7.3 18.9 280 37 19 6.7 3.7 | -6.7 19.9 265 35 18 7.6 4.2
11750 -6.8 19.8 280 36 19 8.2 4.5 | -6.1 21.0 265 34 17 9.8 5.4
11500 -6.1 21.0 280 35 18 8.4 4.6 | -5.3 22.5 265 32 16 9.8 5.4
11250 -5.6 21.9 280 34 18 6.9 3.8 | -4.7 23.5 265 30 16 7.8 4.3
11000 -5.1 22.8 280 33 17 6.7 3.7 | -4.1 24.6 265 29 15 7.9 4.3
10750 -4.6 23.7 280 32 17 6.9 3.8 | -3.5 25.7 265 27 14 8.1 4.5
10500 -4.1 24.6 280 31 16 7.0 3.9 | -2.9 26.8 265 26 13 9.3 5.1
10250 -3.6 25.5 280 30 15 8.3 4.6 | -2.2 28.0 265 24 12 10.1 5.5
10000 -2.9 26.8 275 28 14 9.2 5.1 | -1.4 29.5 265 23 12 10.1 5.6
9750 -2.2 28.0 275 27 14 9.4 5.1 | -0.7 30.7 265 22 11 10.1 5.6
9500 -1.5 29.3 275 25 13 10.2 5.6 | 0.1 32.2 265 21 11 10.2 5.6
9250 -0.8 30.6 275 24 12 10.2 5.6 | 0.8 33.4 265 21 11 10.3 5.7
9000 -0.0 32.0 275 23 12 9.8 5.4 | 1.6 34.9 265 20 10 10.5 5.7
8750 0.7 33.3 275 22 11 10.6 5.8 | 2.4 36.3 265 20 10 10.8 5.9
8500 1.6 34.9 275 22 11 11.7 6.4 | 3.2 37.8 265 19 10 11.1 6.1
8250 2.4 36.3 275 21 11 11.0 6.0 | 4.8 40.6 265 18 9 9.6 5.2
8000 3.2 37.8 275 20 10 9.9 5.5 | 5.7 42.3 265 17 9 18.9 10.4
7750 4.1 39.4 275 18 9 15.4 8.4 | 8.9 48.0 265 15 7 81.3 44.6
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
05/07/2024 at 1500 MDT | 05/07/2024 at 1800 MDT
|
CAPE... +143.1 LI... -1.8 | CAPE... +2.0 LI... +0.7
CINH... 0.0 K Index... +9.2 | CINH... -14.7 K Index... +6.2
|
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 -53.0 -63.4 240 32 17 1.4 0.8 | -53.6 -64.5 250 30 15 1.2 0.6
45000 -50.8 -59.4 250 62 32 1.1 0.6 | -51.9 -61.4 255 55 28 1.3 0.7
40000 -49.9 -57.8 260 70 36 0.6 0.3 | -49.6 -57.3 260 65 33 1.4 0.8
38000 -49.3 -56.7 265 80 41 1.3 0.7 | -48.6 -55.5 265 74 38 1.9 1.0
36000 -48.5 -55.3 265 97 50 1.3 0.7 | -47.5 -53.5 265 88 45 1.9 1.0
34000 -47.6 -53.7 265 113 58 4.1 2.2 | -46.3 -51.3 265 101 52 3.3 1.8
32000 -44.7 -48.5 265 116 60 4.9 2.7 | -44.1 -47.4 260 103 53 3.7 2.0
30000 -41.7 -43.1 260 118 61 5.3 2.9 | -41.8 -43.2 260 104 53 4.0 2.2
29000 -40.1 -40.2 260 114 58 5.5 3.0 | -40.6 -41.1 260 97 50 4.1 2.3
28000 -38.4 -37.1 260 109 56 5.5 3.0 | -39.4 -38.9 260 91 47 4.1 2.3
27000 -36.8 -34.2 265 104 54 5.5 3.0 | -38.1 -36.6 265 84 43 4.1 2.3
26000 -35.1 -31.2 265 100 51 5.9 3.2 | -36.4 -33.5 265 81 42 7.1 3.9
25000 -33.3 -27.9 265 97 50 5.9 3.2 | -34.3 -29.7 265 81 41 7.1 3.9
24000 -31.1 -24.0 265 93 48 5.8 3.2 | -32.1 -25.8 265 80 41 7.1 3.9
23000 -29.1 -20.4 265 87 45 7.0 3.9 | -29.6 -21.3 265 78 40 6.3 3.5
22000 -27.0 -16.6 265 79 41 7.0 3.9 | -27.7 -17.9 260 75 39 6.3 3.5
21000 -24.9 -12.8 265 72 37 6.8 3.7 | -25.9 -14.6 255 73 37 6.6 3.6
20000 -23.5 -10.3 265 65 34 4.4 2.4 | -23.6 -10.5 255 67 34 7.7 4.2
19500 -22.8 -9.0 265 62 32 4.4 2.4 | -22.5 -8.5 255 64 33 7.7 4.2
19000 -22.2 -8.0 265 59 30 4.4 2.4 | -21.3 -6.3 255 60 31 7.7 4.2
18500 -21.5 -6.7 265 56 29 4.2 2.3 | -20.2 -4.4 255 57 29 7.7 4.2
18000 -20.6 -5.1 265 54 28 8.4 4.6 | -18.9 -2.0 255 57 29 8.9 4.9
17500 -19.4 -2.9 265 53 27 8.0 4.4 | -17.6 0.3 255 58 30 8.8 4.8
17000 -18.2 -0.8 265 52 27 8.4 4.6 | -16.3 2.7 255 59 30 8.9 4.9
16500 -17.0 1.4 265 50 26 8.7 4.8 | -15.0 5.0 255 58 30 8.9 4.9
16000 -15.7 3.7 265 48 25 9.0 4.9 | -13.6 7.5 260 57 30 8.8 4.8
15500 -14.3 6.3 265 44 23 9.8 5.4 | -12.4 9.7 260 58 30 8.5 4.7
15000 -12.9 8.8 265 41 21 9.8 5.4 | -11.1 12.0 265 59 31 8.6 4.7
14500 -11.4 11.5 265 38 19 9.9 5.4 | -9.9 14.2 265 59 30 7.0 3.9
14000 -10.0 14.0 265 35 18 9.6 5.3 | -8.8 16.2 265 57 29 7.0 3.8
13500 -8.4 16.9 265 33 17 12.2 6.7 | -7.7 18.1 270 55 28 9.1 5.0
13000 -6.5 20.3 265 33 17 13.0 7.1 | -6.3 20.7 270 51 26 10.2 5.6
12500 -5.6 21.9 265 32 16 4.7 2.6 | -5.6 21.9 275 45 23 4.4 2.4
12000 -4.1 24.6 265 31 16 8.8 4.8 | -4.2 24.4 275 42 22 8.3 4.5
11750 -3.4 25.9 265 31 16 12.2 6.7 | -3.6 25.5 275 40 21 11.9 6.5
11500 -2.4 27.7 265 31 16 11.5 6.3 | -2.6 27.3 275 39 20 11.6 6.3
11250 -1.7 28.9 265 30 16 8.4 4.6 | -1.9 28.6 275 39 20 8.3 4.5
11000 -1.0 30.2 265 30 15 9.1 5.0 | -1.2 29.8 280 38 19 9.2 5.0
10750 -0.4 31.3 265 30 15 9.2 5.1 | -0.6 30.9 280 37 19 8.8 4.8
10500 0.4 32.7 265 29 15 10.3 5.7 | 0.1 32.2 280 36 19 8.7 4.8
10250 1.2 34.2 265 29 15 10.2 5.6 | 0.8 33.4 280 36 18 9.7 5.3
10000 1.9 35.4 265 29 15 9.7 5.3 | 1.5 34.7 280 35 18 10.4 5.7
9750 2.6 36.7 265 28 15 9.9 5.4 | 2.3 36.1 280 35 18 10.2 5.6
9500 3.4 38.1 270 28 14 10.0 5.5 | 3.1 37.6 280 34 18 10.2 5.6
9250 4.1 39.4 270 28 14 10.4 5.7 | 3.8 38.8 280 34 17 10.1 5.6
9000 4.9 40.8 270 27 14 11.0 6.0 | 4.6 40.3 280 33 17 9.8 5.4
8750 5.7 42.3 270 27 14 11.1 6.1 | 5.3 41.5 280 33 17 10.3 5.6
8500 6.6 43.9 270 26 14 11.1 6.1 | 6.1 43.0 280 32 16 11.0 6.0
8250 7.4 45.3 270 26 13 11.6 6.4 | 6.9 44.4 280 31 16 11.2 6.2
8000 8.2 46.8 270 25 13 8.3 4.5 | 7.7 45.9 280 30 15 9.8 5.4
7750 12.1 53.8 270 19 10 91.4 50.2 | 8.5 47.3 285 28 14 12.1 6.6
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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