Soaring Guidance
Issued by NWS Pueblo, CO
Issued by NWS Pueblo, CO
082
UXUS97 KPUB 171231
SRGPUB
Soaring Forecast
National Weather Service Pueblo, Colorado
0631 MDT Monday, March 17, 2025
This forecast is for the Air Force Academy for Monday, March 17, 2025:
If the trigger temperature of 57.7 F/14.3 C is reached...then
Thermal Soaring Index....................... Good
Maximum rate of lift........................ 902 ft/min (4.6 m/s)
Maximum height of thermals.................. 18434 ft MSL (10821 ft AGL)
Forecast maximum temperature................... 68.0 F/20.5 C
Time of trigger temperature.................... 0945 MDT
Time of overdevelopment........................ None
Middle/high clouds during soaring window....... Overcast thin high
Surface winds during soaring window............ Between 20 mph and 30 mph
Height of the -3 thermal index................. 14478 ft MSL (6865 ft AGL)
Thermal soaring outlook for Tuesday 03/18...... Excellent
Wave Soaring Index............................. Not available
Remarks...
Sunrise/Sunset.................... 07:06:27 / 19:08:25 MDT
Total possible sunshine........... 12 hr 1 min 59 sec (721 min 59 sec)
Altitude of sun at 13:07:26 MDT... 49.96 degrees
Upper air data from numerical model forecast valid on 03/17/2025 at 0600 MDT
Freezing level.................. 12766 ft MSL (5153 ft AGL)
Convective condensation level... 23463 ft MSL (15850 ft AGL)
Lifted condensation level....... 22592 ft MSL (14979 ft AGL)
Lifted index.................... +2.2
K index......................... -11.5
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 -85.7 270 79 41 3.7 2.0 M M M M M
45000 -60.0 -76.0 270 84 43 1.4 0.8 M M M M M
40000 -57.6 -71.7 275 86 44 1.6 0.9 M M M M M
38000 -54.8 -66.6 275 88 45 5.3 2.9 M M M M M
36000 -51.7 -61.1 275 91 47 5.3 2.9 M M M M M
34000 -48.3 -54.9 275 89 46 6.3 3.4 M M M M M
32000 -44.5 -48.1 275 80 41 6.2 3.4 M M M M M
30000 -40.5 -40.9 275 71 36 7.6 4.2 27.9 82.3 6.1 M M
29000 -38.2 -36.8 275 64 33 7.6 4.2 27.0 80.6 5.5 M M
28000 -36.0 -32.8 275 58 30 7.6 4.2 26.3 79.3 4.9 M M
27000 -33.7 -28.7 275 52 27 7.9 4.3 25.6 78.0 4.4 M M
26000 -31.3 -24.3 275 49 25 7.9 4.3 24.8 76.6 3.8 M M
25000 -29.0 -20.2 275 46 23 7.9 4.3 24.1 75.3 3.3 M M
24000 -26.6 -15.9 275 42 22 8.1 4.5 23.5 74.3 2.9 M M
23000 -24.1 -11.4 275 40 20 8.3 4.6 22.9 73.2 2.4 M M
22000 -21.0 -5.8 280 36 19 8.3 4.6 22.3 72.1 1.9 M M
21000 -18.6 -1.5 280 34 18 7.8 4.3 21.8 71.2 1.4 M M
20000 -16.2 2.8 285 32 17 7.9 4.3 21.1 69.9 0.8 M M
19500 -15.0 5.0 285 31 16 7.9 4.3 20.8 69.4 0.6 M M
19000 -13.9 7.0 285 30 16 7.9 4.3 20.5 68.9 0.3 M M
18500 -12.7 9.1 285 31 16 7.4 4.1 20.1 68.2 0.0 M M
18000 -11.6 11.1 285 33 17 7.4 4.1 19.7 67.5 -0.4 955 4.9
17500 -10.5 13.1 285 34 18 7.4 4.0 19.4 66.9 -0.7 907 4.6
17000 -9.4 15.1 285 35 18 7.3 4.0 18.9 66.1 -1.1 859 4.4
16500 -8.3 17.1 285 36 19 7.3 4.0 18.5 65.4 -1.5 812 4.1
16000 -7.2 19.0 285 37 19 7.3 4.0 18.1 64.7 -1.8 764 3.9
15500 -6.1 21.0 285 37 19 7.4 4.0 17.7 63.9 -2.2 716 3.6
15000 -5.0 23.0 285 38 20 7.1 3.9 17.3 63.2 -2.6 668 3.4
14500 -3.9 25.0 285 40 21 7.1 3.9 16.9 62.4 -3.0 621 3.2
14000 -2.9 26.8 280 42 22 7.2 3.9 16.5 61.7 -3.4 574 2.9
13500 -1.8 28.8 280 43 22 7.3 4.0 16.1 60.9 -3.8 527 2.7
13000 -0.7 30.7 275 43 22 8.7 4.8 15.7 60.2 -4.2 480 2.4
12500 0.4 32.7 275 44 22 5.7 3.1 15.4 59.6 -4.5 431 2.2
12000 1.4 34.5 275 44 23 6.4 3.5 14.8 58.6 -5.1 388 2.0
11750 1.9 35.4 275 43 22 6.8 3.7 14.6 58.2 -5.3 366 1.9
11500 2.4 36.3 275 43 22 7.6 4.2 14.3 57.8 -5.5 343 1.7
11250 3.0 37.4 275 41 21 8.6 4.7 14.2 57.6 -5.7 316 1.6
11000 3.6 38.5 275 40 20 8.0 4.4 14.1 57.4 -5.8 290 1.5
10750 4.2 39.6 270 37 19 7.5 4.1 14.0 57.1 -5.9 266 1.3
10500 4.8 40.6 270 33 17 7.2 4.0 13.8 56.8 -6.1 241 1.2
10250 5.3 41.5 270 30 16 6.9 3.8 13.6 56.4 -6.4 218 1.1
10000 5.7 42.3 270 30 16 4.9 2.7 13.3 55.9 -6.7 198 1.0
9750 6.0 42.8 270 32 17 2.7 1.5 12.8 55.0 -7.2 184 0.9
9500 6.1 43.0 270 35 18 2.6 1.4 12.2 54.0 -7.8 171 0.9
9250 6.3 43.3 270 37 19 2.2 1.2 11.7 53.1 -8.4 159 0.8
9000 6.3 43.3 270 41 21 -2.1 -1.2 11.0 51.8 -9.2 153 0.8
8750 5.9 42.6 270 42 22 -5.3 -2.9 9.9 49.8 -10.3 157 0.8
8500 5.5 41.9 270 44 22 -4.1 -2.2 8.8 47.9 -11.5 162 0.8
8250 5.1 41.2 265 45 23 -6.4 -3.5 7.7 45.9 -12.7 167 0.8
8000 4.5 40.1 265 43 22 -5.6 -3.1 6.5 43.6 -14.0 177 0.9
7750 4.3 39.7 265 32 17 2.2 1.2 5.6 42.1 -14.9 174 0.9
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 * * * * * *
03/17/2025 at 0900 MDT | 03/17/2025 at 1200 MDT
|
CAPE... 0.0 LI... +2.0 | CAPE... 0.0 LI... +3.1
CINH... 0.0 K Index... -5.0 | CINH... 0.0 K Index... -5.7
|
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 -65.4 -85.7 265 76 39 3.0 1.7 | -66.4 -87.5 265 82 42 4.2 2.3
45000 -61.0 -77.8 270 76 39 2.1 1.1 | -60.3 -76.5 265 77 40 1.5 0.8
40000 -57.8 -72.0 270 92 47 2.2 1.2 | -57.8 -72.0 265 91 47 1.7 0.9
38000 -55.2 -67.4 270 94 48 5.3 2.9 | -55.4 -67.7 265 95 49 4.6 2.5
36000 -51.6 -60.9 270 93 48 5.3 2.9 | -52.6 -62.7 265 97 50 4.6 2.5
34000 -48.1 -54.6 270 90 46 6.4 3.5 | -49.1 -56.4 265 96 49 7.7 4.2
32000 -44.3 -47.7 270 83 43 6.4 3.5 | -44.5 -48.1 265 89 46 7.7 4.2
30000 -40.1 -40.2 265 73 38 7.9 4.3 | -39.9 -39.8 265 80 41 7.5 4.1
29000 -37.7 -35.9 265 67 34 7.9 4.3 | -37.7 -35.9 265 74 38 7.5 4.1
28000 -35.4 -31.7 265 60 31 7.9 4.3 | -35.5 -31.9 265 68 35 7.5 4.1
27000 -33.0 -27.4 260 54 28 8.0 4.4 | -33.1 -27.6 260 63 32 9.4 5.2
26000 -30.6 -23.1 260 51 26 8.0 4.4 | -30.3 -22.5 260 60 31 9.2 5.0
25000 -28.2 -18.8 260 47 24 8.0 4.4 | -27.6 -17.7 260 57 30 9.2 5.0
24000 -25.9 -14.6 260 43 22 7.6 4.2 | -24.9 -12.8 260 55 28 7.7 4.2
23000 -23.6 -10.5 260 40 21 7.5 4.1 | -22.3 -8.1 260 49 25 7.0 3.8
22000 -21.4 -6.5 265 38 19 7.5 4.1 | -20.2 -4.4 260 45 23 7.0 3.9
21000 -18.5 -1.3 265 35 18 8.1 4.4 | -18.0 -0.4 260 42 21 7.7 4.2
20000 -16.1 3.0 265 33 17 8.1 4.4 | -15.7 3.7 265 40 20 7.7 4.2
19500 -14.9 5.2 265 31 16 8.1 4.4 | -14.6 5.7 265 39 20 7.7 4.2
19000 -13.7 7.3 265 30 16 8.1 4.4 | -13.4 7.9 265 38 19 7.7 4.2
18500 -12.5 9.5 265 31 16 8.4 4.6 | -12.2 10.0 265 36 18 8.1 4.4
18000 -11.2 11.8 265 31 16 8.4 4.6 | -11.0 12.2 270 34 17 8.0 4.4
17500 -10.0 14.0 265 32 17 8.1 4.5 | -9.8 14.4 270 32 17 7.7 4.2
17000 -8.8 16.2 265 32 16 8.0 4.4 | -8.7 16.3 270 35 18 7.6 4.2
16500 -7.6 18.3 270 31 16 8.0 4.4 | -7.6 18.3 270 38 20 7.5 4.1
16000 -6.4 20.5 270 31 16 7.8 4.3 | -6.5 20.3 270 39 20 6.8 3.7
15500 -5.2 22.6 270 31 16 7.9 4.3 | -5.5 22.1 275 40 20 6.8 3.7
15000 -4.1 24.6 270 32 16 7.7 4.2 | -4.5 23.9 275 41 21 6.9 3.8
14500 -2.9 26.8 270 32 16 7.7 4.2 | -3.5 25.7 275 42 22 6.9 3.8
14000 -1.8 28.8 270 33 17 7.4 4.0 | -2.4 27.7 275 44 23 7.0 3.8
13500 -0.7 30.7 270 34 18 7.2 4.0 | -1.4 29.5 275 44 23 7.2 4.0
13000 0.4 32.7 270 36 19 6.9 3.8 | -0.3 31.5 270 45 23 9.1 5.0
12500 1.1 34.0 270 38 19 4.2 2.3 | 0.9 33.6 270 46 24 5.6 3.1
12000 1.8 35.2 270 41 21 4.3 2.3 | 1.8 35.2 270 47 24 6.3 3.5
11750 2.1 35.8 270 42 21 4.0 2.2 | 2.4 36.3 270 47 24 6.9 3.8
11500 2.4 36.3 270 42 22 4.4 2.4 | 2.9 37.2 265 47 24 6.5 3.5
11250 2.8 37.0 265 42 22 4.7 2.6 | 3.4 38.1 265 47 24 6.3 3.5
11000 3.1 37.6 265 42 22 4.9 2.7 | 3.8 38.8 265 47 24 5.9 3.2
10750 3.5 38.3 265 44 22 5.2 2.9 | 4.2 39.6 265 47 24 5.0 2.7
10500 3.9 39.0 265 45 23 5.1 2.8 | 4.6 40.3 265 48 25 4.9 2.7
10250 4.3 39.7 265 47 24 7.2 3.9 | 5.0 41.0 265 49 25 4.4 2.4
10000 4.9 40.8 265 48 25 6.7 3.7 | 5.3 41.5 260 49 25 4.4 2.4
9750 5.3 41.5 265 48 25 4.4 2.4 | 5.6 42.1 260 47 24 5.0 2.7
9500 5.6 42.1 265 48 25 4.6 2.5 | 5.9 42.6 260 44 23 4.7 2.6
9250 6.0 42.8 265 48 25 4.5 2.5 | 6.2 43.2 260 42 21 6.5 3.6
9000 6.2 43.2 265 48 25 1.6 0.9 | 6.8 44.2 260 38 20 9.8 5.3
8750 6.1 43.0 265 46 24 -0.4 -0.2 | 7.5 45.5 260 36 19 10.6 5.8
8500 6.1 43.0 265 44 22 0.5 0.3 | 8.3 46.9 260 34 18 10.0 5.5
8250 6.0 42.8 265 41 21 -0.1 -0.0 | 9.0 48.2 260 33 17 11.7 6.4
8000 6.0 42.8 265 38 20 4.2 2.3 | 10.1 50.2 260 31 16 17.5 9.6
7750 6.6 43.9 265 29 15 12.3 6.7 | 11.6 52.9 260 26 13 22.3 12.2
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
03/17/2025 at 1500 MDT | 03/17/2025 at 1800 MDT
|
CAPE... 0.0 LI... +3.7 | CAPE... 0.0 LI... +5.5
CINH... 0.0 K Index... +1.5 | CINH... 0.0 K Index... +2.2
|
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 -66.1 -87.0 265 79 41 4.4 2.4 | -65.1 -85.2 255 78 40 4.0 2.2
45000 -59.6 -75.3 260 82 42 2.3 1.3 | -59.4 -74.9 255 84 43 1.1 0.6
40000 -55.7 -68.3 265 93 48 2.5 1.4 | -57.2 -71.0 260 93 48 1.4 0.8
38000 -54.2 -65.6 265 96 49 2.5 1.4 | -55.4 -67.7 260 98 50 3.3 1.8
36000 -52.7 -62.9 260 98 51 2.5 1.4 | -53.5 -64.3 260 103 53 3.3 1.8
34000 -50.0 -58.0 260 99 51 7.9 4.4 | -50.4 -58.7 255 102 53 8.4 4.6
32000 -45.2 -49.4 260 96 50 7.9 4.3 | -45.4 -49.7 255 93 48 8.4 4.6
30000 -40.4 -40.7 260 90 46 8.2 4.5 | -40.3 -40.5 255 82 42 8.5 4.7
29000 -38.0 -36.4 260 84 43 8.2 4.5 | -37.8 -36.0 255 76 39 8.5 4.6
28000 -35.5 -31.9 260 77 40 8.2 4.5 | -35.2 -31.4 255 70 36 8.5 4.7
27000 -33.0 -27.4 260 71 37 8.3 4.6 | -32.7 -26.9 255 64 33 7.9 4.3
26000 -30.5 -22.9 260 66 34 8.3 4.6 | -30.4 -22.7 255 58 30 7.8 4.3
25000 -28.1 -18.6 260 61 31 8.4 4.6 | -28.1 -18.6 255 53 27 7.8 4.3
24000 -25.6 -14.1 260 56 29 7.7 4.2 | -25.7 -14.3 255 47 24 8.4 4.6
23000 -22.9 -9.2 260 52 27 7.3 4.0 | -22.4 -8.3 260 44 23 9.0 4.9
22000 -20.7 -5.3 260 49 25 7.3 4.0 | -19.7 -3.5 260 42 22 9.0 4.9
21000 -18.4 -1.1 255 46 24 8.2 4.5 | -17.2 1.0 260 42 21 6.9 3.8
20000 -16.0 3.2 255 44 23 8.2 4.5 | -15.1 4.8 260 45 23 7.0 3.8
19500 -14.7 5.5 255 43 22 8.2 4.5 | -14.1 6.6 260 47 24 7.0 3.8
19000 -13.5 7.7 255 42 22 8.2 4.5 | -13.0 8.6 260 49 25 7.1 3.9
18500 -12.3 9.9 255 41 21 8.5 4.7 | -12.1 10.2 260 50 26 6.0 3.3
18000 -11.0 12.2 255 38 20 8.4 4.6 | -11.2 11.8 255 52 27 6.0 3.3
17500 -9.8 14.4 255 35 18 7.2 4.0 | -10.3 13.5 255 53 27 5.9 3.3
17000 -8.8 16.2 255 38 19 6.2 3.4 | -9.4 15.1 255 52 27 5.8 3.2
16500 -7.9 17.8 255 40 21 6.1 3.3 | -8.5 16.7 255 51 26 6.1 3.3
16000 -7.1 19.2 255 40 21 4.9 2.7 | -7.9 17.8 255 51 26 2.8 1.5
15500 -6.4 20.5 255 39 20 4.9 2.7 | -7.4 18.7 255 51 26 3.0 1.7
15000 -5.5 22.1 255 39 20 6.8 3.7 | -6.9 19.6 255 50 26 5.3 2.9
14500 -4.5 23.9 260 39 20 7.0 3.8 | -6.0 21.2 255 47 24 5.9 3.2
14000 -3.4 25.9 260 40 21 7.0 3.9 | -5.1 22.8 250 44 23 7.2 4.0
13500 -2.4 27.7 260 40 21 7.2 3.9 | -3.9 25.0 250 42 22 8.7 4.8
13000 -1.3 29.7 260 40 21 8.6 4.7 | -2.6 27.3 250 40 21 11.8 6.5
12500 -0.2 31.6 260 40 20 5.5 3.0 | -1.0 30.2 250 39 20 7.2 4.0
12000 0.6 33.1 255 39 20 6.7 3.7 | 0.2 32.4 250 38 19 8.6 4.7
11750 1.2 34.2 255 38 20 8.5 4.7 | 0.9 33.6 250 37 19 10.2 5.6
11500 1.8 35.2 255 36 19 8.8 4.9 | 1.7 35.1 250 36 19 10.0 5.5
11250 2.5 36.5 255 35 18 8.8 4.8 | 2.4 36.3 250 36 18 9.5 5.2
11000 3.1 37.6 255 33 17 9.0 4.9 | 3.1 37.6 250 35 18 9.5 5.2
10750 3.8 38.8 255 32 17 9.2 5.0 | 3.8 38.8 250 35 18 8.9 4.9
10500 4.5 40.1 255 32 16 9.5 5.2 | 4.5 40.1 250 34 17 9.0 4.9
10250 5.2 41.4 255 31 16 10.8 5.9 | 5.2 41.4 250 33 17 10.5 5.8
10000 6.1 43.0 255 31 16 10.9 6.0 | 6.0 42.8 250 33 17 10.7 5.9
9750 6.8 44.2 255 31 16 9.9 5.5 | 6.8 44.2 250 32 16 9.8 5.4
9500 7.6 45.7 255 30 16 9.6 5.3 | 7.5 45.5 250 31 16 9.3 5.1
9250 8.3 46.9 255 30 15 10.6 5.8 | 8.2 46.8 250 30 16 10.4 5.7
9000 9.1 48.4 255 29 15 11.4 6.3 | 9.0 48.2 250 29 15 10.8 5.9
8750 10.0 50.0 255 29 15 10.6 5.8 | 9.8 49.6 250 28 15 9.5 5.2
8500 10.8 51.4 255 28 14 11.4 6.2 | 10.5 50.9 255 27 14 9.6 5.2
8250 11.6 52.9 255 27 14 8.6 4.7 | 11.2 52.2 255 26 13 8.9 4.9
8000 12.3 54.1 255 26 13 13.9 7.6 | 11.8 53.2 255 24 12 9.1 5.0
7750 13.9 57.0 255 22 11 30.7 16.8 | 12.6 54.7 255 19 10 11.8 6.5
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