Soaring Guidance
Issued by NWS Pueblo, CO
Issued by NWS Pueblo, CO
950
UXUS97 KPUB 071242
SRGPUB
Soaring Forecast
National Weather Service Pueblo, Colorado
0542 MST Friday, February 7, 2025
This forecast is for the Air Force Academy for Friday, February 7, 2025:
If the trigger temperature of 54.6 F/12.6 C is reached...then
Thermal Soaring Index....................... Fair
Maximum rate of lift........................ 402 ft/min (2.0 m/s)
Maximum height of thermals.................. 12782 ft MSL (5170 ft AGL)
Forecast maximum temperature................... 60.0 F/16.0 C
Time of trigger temperature.................... 1000 MST
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................. 11527 ft MSL (3915 ft AGL)
Thermal soaring outlook for Saturday 02/08..... Fair
Wave Soaring Index............................. Not available
Remarks...
Sunrise/Sunset.................... 06:59:09 / 17:27:43 MST
Total possible sunshine........... 10 hr 28 min 34 sec (628 min 34 sec)
Altitude of sun at 12:13:26 MST... 35.88 degrees
Upper air data from numerical model forecast valid on 02/07/2025 at 0500 MST
Freezing level.................. 12573 ft MSL (4961 ft AGL)
Convective condensation level... 22656 ft MSL (15044 ft AGL)
Lifted condensation level....... 19676 ft MSL (12064 ft AGL)
Lifted index.................... +5.4
K index......................... -18.0
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 -64.7 -84.5 265 96 49 3.4 1.9 M M M M M
45000 -59.6 -75.3 260 112 58 3.7 2.0 M M M M M
40000 -53.9 -65.0 265 116 60 3.6 2.0 M M M M M
38000 -52.7 -62.9 265 110 57 1.3 0.7 M M M M M
36000 -52.0 -61.6 270 102 52 1.2 0.7 M M M M M
34000 -49.9 -57.8 270 95 49 7.6 4.2 M M M M M
32000 -45.3 -49.5 270 90 46 7.6 4.2 M M M M M
30000 -40.6 -41.1 270 86 44 8.2 4.5 27.7 81.8 9.4 M M
29000 -38.2 -36.8 270 84 43 8.2 4.5 27.0 80.6 8.9 M M
28000 -35.7 -32.3 270 83 43 8.2 4.5 26.5 79.7 8.6 M M
27000 -33.2 -27.8 265 81 42 8.7 4.8 26.0 78.8 8.4 M M
26000 -30.6 -23.1 265 79 41 8.7 4.8 25.5 78.0 8.1 M M
25000 -28.0 -18.4 265 77 40 8.7 4.8 25.2 77.3 7.9 M M
24000 -24.7 -12.5 265 75 38 8.2 4.5 24.8 76.6 7.6 M M
23000 -22.3 -8.1 265 72 37 8.2 4.5 24.1 75.5 7.2 M M
22000 -19.8 -3.6 265 69 36 8.2 4.5 23.6 74.5 6.9 M M
21000 -17.3 0.9 265 65 34 8.9 4.9 23.2 73.8 6.6 M M
20000 -14.6 5.7 265 59 30 8.8 4.9 22.8 73.1 6.3 M M
19500 -13.3 8.1 265 56 29 8.8 4.9 22.7 72.9 6.2 M M
19000 -11.9 10.6 265 52 27 8.8 4.8 22.6 72.7 6.2 M M
18500 -10.6 12.9 265 51 26 9.1 5.0 22.5 72.5 6.1 M M
18000 -9.2 15.4 265 53 27 9.1 5.0 22.4 72.2 6.0 M M
17500 -7.9 17.8 265 55 28 8.6 4.7 22.3 72.1 6.0 M M
17000 -6.7 19.9 265 56 29 7.8 4.3 21.9 71.5 5.7 M M
16500 -5.5 22.1 265 56 29 8.1 4.4 21.6 70.9 5.5 M M
16000 -4.5 23.9 265 56 29 5.6 3.1 21.2 70.1 5.1 M M
15500 -3.6 25.5 265 55 28 5.8 3.2 20.5 68.9 4.5 M M
15000 -2.8 27.0 265 54 28 4.9 2.7 19.8 67.7 3.9 M M
14500 -2.1 28.2 265 52 27 4.5 2.5 19.0 66.2 3.1 M M
14000 -1.5 29.3 265 50 26 4.2 2.3 18.1 64.7 2.3 M M
13500 -0.9 30.4 265 51 26 3.7 2.0 17.2 62.9 1.4 M M
13000 -0.4 31.3 265 51 26 4.5 2.5 16.2 61.2 0.4 M M
12500 0.0 32.0 265 52 27 0.8 0.5 15.1 59.2 -0.6 392 2.0
12000 0.1 32.2 265 54 28 1.3 0.7 13.8 56.8 -2.0 374 1.9
11750 0.3 32.5 265 52 27 3.3 1.8 13.2 55.7 -2.6 362 1.8
11500 0.6 33.1 265 45 23 5.2 2.8 12.8 55.0 -3.0 344 1.7
11250 1.0 33.8 260 39 20 5.3 2.9 12.4 54.3 -3.3 325 1.7
11000 1.4 34.5 260 34 17 5.3 2.9 12.1 53.7 -3.7 306 1.6
10750 1.8 35.2 260 30 16 5.9 3.3 11.7 53.1 -4.0 286 1.5
10500 2.3 36.1 260 33 17 6.3 3.5 11.5 52.6 -4.3 265 1.3
10250 2.8 37.0 260 35 18 6.3 3.5 11.2 52.1 -4.5 243 1.2
10000 3.2 37.8 260 37 19 6.2 3.4 10.9 51.7 -4.8 221 1.1
9750 3.7 38.7 260 39 20 4.7 2.6 10.6 51.1 -5.1 201 1.0
9500 4.0 39.2 260 41 21 3.9 2.1 10.2 50.3 -5.6 185 0.9
9250 4.3 39.7 260 43 22 4.1 2.3 9.7 49.5 -6.0 168 0.9
9000 4.5 40.1 260 44 23 2.2 1.2 9.3 48.7 -6.5 153 0.8
8750 4.6 40.3 260 43 22 -0.8 -0.4 8.5 47.4 -7.2 145 0.7
8500 4.4 39.9 260 41 21 -2.1 -1.1 7.7 45.8 -8.1 141 0.7
8250 4.3 39.7 260 39 20 -0.1 -0.0 6.8 44.3 -9.0 137 0.7
8000 4.3 39.7 260 36 19 -4.7 -2.6 6.0 42.9 -9.8 132 0.7
7750 3.4 38.1 260 25 13 -18.0 -9.9 4.4 40.0 -11.4 151 0.8
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 * * * * * *
02/07/2025 at 0800 MST | 02/07/2025 at 1100 MST
|
CAPE... 0.0 LI... +1.8 | CAPE... 0.0 LI... +2.8
CINH... 0.0 K Index... -13.8 | CINH... 0.0 K Index... -10.5
|
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 -65.8 -86.4 260 97 50 2.9 1.6 | -65.4 -85.7 265 98 50 2.5 1.4
45000 -61.4 -78.5 260 112 58 3.5 1.9 | -61.1 -78.0 260 107 55 3.9 2.2
40000 -56.1 -69.0 265 105 54 3.4 1.9 | -55.1 -67.2 260 104 54 4.0 2.2
38000 -54.1 -65.4 270 99 51 3.2 1.7 | -53.2 -63.8 260 94 48 3.0 1.6
36000 -52.2 -62.0 270 91 47 3.2 1.7 | -51.4 -60.5 260 81 42 3.0 1.6
34000 -49.1 -56.4 275 86 44 8.4 4.6 | -48.4 -55.1 260 73 37 7.9 4.4
32000 -44.0 -47.2 270 84 43 8.4 4.6 | -43.7 -46.7 260 71 36 7.9 4.3
30000 -39.0 -38.2 270 82 42 8.4 4.6 | -38.8 -37.8 265 71 36 8.7 4.8
29000 -36.5 -33.7 270 80 41 8.4 4.6 | -36.1 -33.0 260 72 37 8.7 4.8
28000 -34.0 -29.2 270 78 40 8.4 4.6 | -33.5 -28.3 260 74 38 8.7 4.8
27000 -31.5 -24.7 265 77 40 7.6 4.2 | -30.9 -23.6 260 75 39 9.0 5.0
26000 -29.2 -20.6 265 75 39 7.7 4.2 | -27.5 -17.5 260 75 38 9.0 5.0
25000 -26.4 -15.5 265 73 38 7.7 4.2 | -24.8 -12.6 260 74 38 9.1 5.0
24000 -24.0 -11.2 265 72 37 8.4 4.6 | -22.2 -8.0 260 74 38 6.9 3.8
23000 -21.5 -6.7 265 69 36 8.4 4.6 | -20.0 -4.0 260 73 37 7.2 3.9
22000 -19.0 -2.2 265 67 34 8.4 4.6 | -17.9 -0.2 260 71 37 7.2 3.9
21000 -16.6 2.1 265 62 32 7.8 4.3 | -15.7 3.7 260 69 36 7.8 4.3
20000 -14.2 6.4 265 55 28 7.9 4.3 | -13.4 7.9 260 67 34 7.8 4.3
19500 -13.1 8.4 265 51 26 7.9 4.3 | -12.2 10.0 260 65 34 7.8 4.3
19000 -11.9 10.6 265 48 25 7.7 4.2 | -11.0 12.2 260 64 33 8.0 4.4
18500 -10.6 12.9 265 46 23 9.3 5.1 | -10.0 14.0 265 64 33 6.6 3.6
18000 -9.2 15.4 265 46 23 9.2 5.1 | -9.0 15.8 265 67 34 6.6 3.6
17500 -7.8 18.0 265 46 23 8.9 4.9 | -8.0 17.6 265 69 36 7.0 3.8
17000 -6.5 20.3 265 47 24 8.4 4.6 | -6.9 19.6 265 67 35 7.9 4.3
16500 -5.3 22.5 265 48 25 8.4 4.6 | -5.7 21.7 265 64 33 8.0 4.4
16000 -4.0 24.8 265 50 26 8.1 4.5 | -4.6 23.7 265 63 33 7.1 3.9
15500 -2.8 27.0 265 53 27 8.2 4.5 | -3.5 25.7 265 64 33 7.2 3.9
15000 -1.6 29.1 265 55 28 6.6 3.6 | -2.4 27.7 265 65 33 7.5 4.1
14500 -0.7 30.7 265 56 29 6.0 3.3 | -1.2 29.8 265 61 32 7.7 4.2
14000 0.2 32.4 265 58 30 5.8 3.2 | -0.0 32.0 265 58 30 7.3 4.0
13500 1.0 33.8 265 56 29 5.6 3.1 | 1.0 33.8 265 57 29 6.3 3.5
13000 1.8 35.2 265 54 28 7.5 4.1 | 1.9 35.4 265 56 29 8.8 4.8
12500 2.7 36.9 265 52 27 2.3 1.3 | 3.0 37.4 260 51 26 4.0 2.2
12000 3.1 37.6 260 48 25 3.0 1.6 | 3.7 38.7 260 45 23 4.6 2.5
11750 3.4 38.1 260 48 25 4.6 2.5 | 4.1 39.4 260 43 22 5.3 2.9
11500 3.7 38.7 260 50 26 2.3 1.3 | 4.5 40.1 260 43 22 4.4 2.4
11250 3.7 38.7 260 51 26 -0.7 -0.4 | 4.7 40.5 260 43 22 3.0 1.6
11000 3.6 38.5 260 52 27 0.1 0.1 | 5.0 41.0 260 42 22 4.2 2.3
10750 3.6 38.5 260 53 27 0.2 0.1 | 5.2 41.4 260 42 21 0.4 0.2
10500 3.6 38.5 265 54 28 0.5 0.3 | 5.0 41.0 260 47 24 -3.2 -1.8
10250 3.6 38.5 265 56 29 -0.5 -0.3 | 4.7 40.5 260 52 27 -4.3 -2.3
10000 3.5 38.3 265 56 29 -1.1 -0.6 | 4.2 39.6 260 55 28 -6.2 -3.4
9750 3.4 38.1 265 56 29 0.8 0.4 | 3.8 38.8 265 57 29 -3.8 -2.1
9500 3.5 38.3 265 53 27 1.7 0.9 | 3.5 38.3 265 53 27 -2.8 -1.6
9250 3.6 38.5 265 51 26 2.1 1.1 | 3.3 37.9 265 49 25 -1.2 -0.7
9000 3.7 38.7 265 50 26 2.2 1.2 | 3.3 37.9 265 45 23 3.5 1.9
8750 3.8 38.8 265 49 25 -0.3 -0.1 | 3.7 38.7 265 41 21 8.2 4.5
8500 3.7 38.7 265 44 23 -1.6 -0.9 | 4.4 39.9 265 38 20 10.5 5.8
8250 3.7 38.7 265 40 21 -0.5 -0.3 | 5.2 41.4 265 36 18 9.0 4.9
8000 3.7 38.7 265 25 13 -0.5 -0.3 | 6.8 44.2 265 26 13 16.4 9.0
7750 3.6 38.5 265 14 7 -3.0 -1.6 | 8.1 46.6 265 18 9 16.5 9.0
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
02/07/2025 at 1400 MST | 02/07/2025 at 1700 MST
|
CAPE... 0.0 LI... +2.7 | CAPE... 0.0 LI... +3.5
CINH... 0.0 K Index... -10.9 | CINH... 0.0 K Index... -13.1
|
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 -66.0 -86.8 265 86 44 3.0 1.6 | -64.3 -83.7 265 78 40 2.7 1.5
45000 -61.1 -78.0 265 102 52 4.6 2.5 | -59.9 -75.8 265 96 49 4.3 2.4
40000 -54.1 -65.4 265 104 54 4.6 2.5 | -53.3 -63.9 265 106 54 4.4 2.4
38000 -51.8 -61.2 260 99 51 3.5 1.9 | -50.8 -59.4 265 102 53 3.5 1.9
36000 -49.7 -57.5 260 91 47 3.5 1.9 | -48.7 -55.7 265 97 50 3.5 1.9
34000 -46.6 -51.9 255 84 43 6.3 3.5 | -45.8 -50.4 265 92 47 6.8 3.7
32000 -42.8 -45.0 255 78 40 6.3 3.5 | -41.8 -43.2 265 87 45 6.7 3.7
30000 -38.6 -37.5 260 74 38 7.9 4.4 | -37.7 -35.9 260 81 41 7.2 3.9
29000 -36.3 -33.3 260 72 37 7.9 4.4 | -35.5 -31.9 260 76 39 7.2 3.9
28000 -33.9 -29.0 260 71 37 7.9 4.3 | -33.4 -28.1 260 72 37 7.2 3.9
27000 -31.5 -24.7 260 70 36 8.7 4.8 | -31.2 -24.2 260 68 35 7.8 4.3
26000 -28.9 -20.0 260 71 36 8.6 4.7 | -28.8 -19.8 255 63 32 7.9 4.3
25000 -26.3 -15.3 260 72 37 8.6 4.7 | -26.5 -15.7 255 58 30 7.9 4.3
24000 -23.7 -10.7 260 72 37 8.4 4.6 | -24.1 -11.4 250 53 27 8.1 4.4
23000 -21.2 -6.2 260 72 37 8.3 4.6 | -21.6 -6.9 245 51 26 8.4 4.6
22000 -18.7 -1.7 260 71 37 8.3 4.6 | -18.5 -1.3 240 48 25 8.4 4.6
21000 -15.7 3.7 265 71 36 7.7 4.2 | -16.0 3.2 240 48 25 7.4 4.0
20000 -13.4 7.9 265 70 36 7.7 4.2 | -13.8 7.2 250 54 28 7.5 4.1
19500 -12.3 9.9 260 70 36 7.7 4.2 | -12.7 9.1 255 57 29 7.5 4.1
19000 -11.1 12.0 260 70 36 7.8 4.3 | -11.6 11.1 255 60 31 7.6 4.1
18500 -10.0 14.0 260 69 36 7.4 4.1 | -10.5 13.1 260 63 32 6.7 3.7
18000 -8.9 16.0 260 68 35 7.4 4.1 | -9.5 14.9 260 65 34 6.6 3.6
17500 -7.8 18.0 260 67 35 7.3 4.0 | -8.6 16.5 265 68 35 6.5 3.6
17000 -6.8 19.8 260 67 35 7.0 3.9 | -7.6 18.3 265 69 36 6.2 3.4
16500 -5.7 21.7 260 67 35 7.0 3.9 | -6.7 19.9 265 70 36 6.2 3.4
16000 -4.7 23.5 260 66 34 7.5 4.1 | -5.8 21.6 265 70 36 7.2 4.0
15500 -3.6 25.5 260 63 32 7.5 4.1 | -4.7 23.5 265 67 35 7.3 4.0
15000 -2.5 27.5 260 59 31 7.8 4.3 | -3.6 25.5 265 65 33 7.4 4.1
14500 -1.3 29.7 260 56 29 7.9 4.4 | -2.5 27.5 265 63 33 7.5 4.1
14000 -0.1 31.8 260 53 27 8.2 4.5 | -1.4 29.5 265 62 32 7.4 4.1
13500 1.2 34.2 260 51 26 9.0 4.9 | -0.3 31.5 265 57 29 7.1 3.9
13000 2.5 36.5 260 49 25 11.2 6.1 | 0.8 33.4 265 52 27 7.4 4.0
12500 3.8 38.8 260 50 26 3.7 2.0 | 1.4 34.5 265 54 28 1.4 0.8
12000 4.5 40.1 260 49 25 4.9 2.7 | 1.8 35.2 265 61 31 2.0 1.1
11750 4.8 40.6 260 49 25 2.9 1.6 | 1.9 35.4 265 64 33 1.9 1.0
11500 4.9 40.8 260 54 28 0.7 0.4 | 2.0 35.6 265 60 31 0.6 0.3
11250 5.0 41.0 260 57 30 0.7 0.4 | 2.0 35.6 260 59 30 0.2 0.1
11000 5.1 41.2 260 61 31 1.1 0.6 | 2.0 35.6 260 58 30 -0.5 -0.3
10750 5.1 41.2 260 64 33 -0.5 -0.3 | 2.0 35.6 260 58 30 2.8 1.6
10500 4.9 40.8 260 62 32 -2.3 -1.2 | 2.3 36.1 260 53 27 6.3 3.4
10250 4.7 40.5 260 59 30 -2.0 -1.1 | 2.7 36.9 255 49 25 4.8 2.6
10000 4.5 40.1 260 57 29 -3.3 -1.8 | 3.0 37.4 255 46 24 3.9 2.1
9750 4.3 39.7 260 54 28 1.1 0.6 | 3.3 37.9 255 43 22 6.7 3.7
9500 4.5 40.1 260 50 26 4.8 2.6 | 3.9 39.0 255 40 21 9.1 5.0
9250 4.8 40.6 260 46 24 4.9 2.7 | 4.5 40.1 255 38 19 8.5 4.6
9000 5.2 41.4 260 42 22 6.9 3.8 | 5.2 41.4 255 35 18 8.6 4.7
8750 5.8 42.4 260 39 20 8.9 4.9 | 5.8 42.4 250 32 17 8.5 4.7
8500 6.5 43.7 260 36 19 10.5 5.8 | 6.4 43.5 250 30 16 8.3 4.6
8250 7.3 45.1 260 34 18 9.4 5.2 | 7.0 44.6 250 28 14 9.0 4.9
8000 8.9 48.0 255 25 13 15.9 8.7 | 7.6 45.7 250 25 13 6.6 3.6
7750 10.3 50.5 255 18 9 21.1 11.6 | 7.9 46.2 250 19 10 -1.0 -0.6
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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