Soaring Guidance
Issued by NWS Pueblo, CO
Issued by NWS Pueblo, CO
210
UXUS97 KPUB 131234
SRGPUB
Soaring Forecast
National Weather Service Pueblo, Colorado
0634 MDT Tuesday, May 13, 2025
This forecast is for the Air Force Academy for Tuesday, May 13, 2025:
If the trigger temperature of 68.3 F/20.2 C is reached...then
Thermal Soaring Index....................... Good
Maximum rate of lift........................ 1513 ft/min (7.7 m/s)
Maximum height of thermals.................. 24658 ft MSL (17041 ft AGL)
Forecast maximum temperature................... 81.0 F/27.7 C
Time of trigger temperature.................... 0915 MDT
Time of overdevelopment........................ None
Middle/high clouds during soaring window....... Broken/overcast thin middle
Surface winds during soaring window............ Between 20 mph and 30 mph
Height of the -3 thermal index................. 19147 ft MSL (11530 ft AGL)
Thermal soaring outlook for Wednesday 05/14.... Excellent
Wave Soaring Index............................. Not available
Remarks...
Sunrise/Sunset.................... 05:47:45 / 20:03:31 MDT
Total possible sunshine........... 14 hr 15 min 46 sec (855 min 46 sec)
Altitude of sun at 12:55:38 MDT... 69.59 degrees
Upper air data from numerical model forecast valid on 05/13/2025 at 0600 MDT
Freezing level.................. 14614 ft MSL (6997 ft AGL)
Convective condensation level... 21598 ft MSL (13981 ft AGL)
Lifted condensation level....... 22232 ft MSL (14616 ft AGL)
Lifted index.................... -2.3
K index......................... -0.9
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 -61.8 -79.2 250 35 18 -1.8 -1.0 M M M M M
45000 -63.8 -82.8 255 44 23 4.0 2.2 M M M M M
40000 -57.8 -72.0 260 40 21 3.6 2.0 M M M M M
38000 -54.6 -66.3 260 35 18 5.6 3.0 M M M M M
36000 -51.3 -60.3 255 29 15 5.6 3.1 M M M M M
34000 -47.1 -52.8 245 25 13 8.2 4.5 M M M M M
32000 -42.2 -44.0 235 22 11 8.2 4.5 M M M M M
30000 -37.4 -35.3 230 21 11 7.5 4.1 30.8 87.5 2.8 M M
29000 -35.1 -31.2 225 21 11 7.6 4.1 29.9 85.9 2.1 M M
28000 -32.9 -27.2 225 21 11 7.6 4.1 29.2 84.5 1.5 M M
27000 -30.5 -22.9 225 20 10 8.4 4.6 28.5 83.3 1.0 M M
26000 -28.0 -18.4 230 18 9 8.4 4.6 27.9 82.2 0.5 M M
25000 -24.9 -12.8 240 16 8 8.4 4.6 27.3 81.2 0.1 M M
24000 -22.3 -8.1 240 16 8 8.9 4.9 26.9 80.5 -0.3 1630 8.3
23000 -19.6 -3.3 240 17 9 8.9 4.9 26.6 79.8 -0.6 1521 7.7
22000 -16.9 1.6 240 18 9 8.8 4.9 26.3 79.4 -0.8 1411 7.2
21000 -14.6 5.7 235 20 10 6.9 3.8 25.6 78.2 -1.4 1311 6.7
20000 -12.5 9.5 230 22 11 6.9 3.8 24.6 76.3 -2.3 1219 6.2
19500 -11.5 11.3 225 23 12 6.9 3.8 24.2 75.5 -2.7 1174 6.0
19000 -10.5 13.1 225 25 13 7.0 3.8 23.7 74.7 -3.2 1128 5.7
18500 -9.4 15.1 220 25 13 7.5 4.1 23.3 73.9 -3.6 1081 5.5
18000 -8.3 17.1 215 25 13 7.5 4.1 22.9 73.2 -4.0 1034 5.3
17500 -7.2 19.0 210 25 13 7.4 4.1 22.5 72.6 -4.3 986 5.0
17000 -6.1 21.0 205 24 12 7.4 4.1 22.1 71.8 -4.8 939 4.8
16500 -5.1 22.8 200 23 12 7.8 4.3 21.8 71.2 -5.2 892 4.5
16000 -3.8 25.2 200 23 12 9.0 4.9 21.6 70.8 -5.4 839 4.3
15500 -2.4 27.7 195 23 12 8.9 4.9 21.4 70.6 -5.6 784 4.0
15000 -1.1 30.0 195 23 12 9.0 5.0 21.3 70.3 -5.7 729 3.7
14500 0.2 32.4 195 22 11 9.0 5.0 21.2 70.1 -5.9 674 3.4
14000 1.6 34.9 195 21 11 9.3 5.1 21.1 69.9 -6.0 618 3.1
13500 3.0 37.4 200 20 10 9.6 5.3 21.0 69.8 -6.1 561 2.9
13000 4.4 39.9 205 20 10 12.6 6.9 21.0 69.7 -6.2 504 2.6
12500 6.0 42.8 210 20 11 5.7 3.2 21.0 69.9 -6.2 443 2.3
12000 7.0 44.6 210 21 11 7.9 4.3 20.6 69.0 -6.6 398 2.0
11750 7.6 45.7 210 20 10 9.8 5.4 20.5 69.0 -6.7 370 1.9
11500 8.3 46.9 210 18 9 8.3 4.5 20.5 68.9 -6.8 343 1.7
11250 8.9 48.0 205 17 9 7.3 4.0 20.3 68.6 -7.0 319 1.6
11000 9.4 48.9 205 17 9 7.6 4.2 20.2 68.3 -7.2 295 1.5
10750 10.0 50.0 205 16 8 7.8 4.3 20.0 68.0 -7.4 270 1.4
10500 10.6 51.1 215 17 9 7.4 4.1 19.8 67.7 -7.5 245 1.2
10250 11.1 52.0 220 17 9 6.2 3.4 19.6 67.3 -7.8 223 1.1
10000 11.5 52.7 225 18 9 5.3 2.9 19.3 66.7 -8.1 203 1.0
9750 11.8 53.2 235 19 10 4.0 2.2 18.9 66.0 -8.6 186 0.9
9500 12.1 53.8 245 20 10 4.0 2.2 18.5 65.2 -9.1 171 0.9
9250 12.3 54.1 250 22 11 2.5 1.4 18.0 64.4 -9.6 156 0.8
9000 12.4 54.3 260 25 13 -0.2 -0.1 17.3 63.2 -10.3 147 0.7
8750 12.3 54.1 265 27 14 -0.4 -0.2 16.5 61.8 -11.1 141 0.7
8500 12.3 54.1 265 29 15 -1.3 -0.7 15.8 60.4 -11.9 135 0.7
8250 12.2 54.0 270 31 16 2.1 1.1 15.0 58.9 -12.7 130 0.7
8000 12.4 54.3 270 32 17 -2.2 -1.2 14.4 57.9 -13.3 117 0.6
7750 11.5 52.7 270 23 12 -20.6 -11.3 12.8 55.1 -15.0 136 0.7
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 * * * * * *
05/13/2025 at 0900 MDT | 05/13/2025 at 1200 MDT
|
CAPE... 0.0 LI... +1.8 | CAPE... 0.0 LI... +1.5
CINH... 0.0 K Index... -5.3 | CINH... 0.0 K Index... +2.8
|
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 -61.5 -78.7 245 35 18 -1.5 -0.8 | -61.3 -78.3 240 36 18 -1.0 -0.6
45000 -63.0 -81.4 245 41 21 2.7 1.5 | -62.2 -80.0 240 45 23 3.1 1.7
40000 -58.8 -73.8 245 30 15 2.7 1.5 | -57.3 -71.1 235 30 15 3.2 1.8
38000 -55.5 -67.9 235 31 16 6.0 3.3 | -54.6 -66.3 235 29 15 5.0 2.7
36000 -52.0 -61.6 225 34 17 6.0 3.3 | -51.6 -60.9 235 29 15 5.0 2.7
34000 -47.6 -53.7 220 34 18 8.9 4.9 | -47.4 -53.3 230 28 14 7.5 4.1
32000 -41.7 -43.1 215 29 15 8.9 4.9 | -42.9 -45.2 220 26 14 7.5 4.1
30000 -36.8 -34.2 215 27 14 7.3 4.0 | -37.9 -36.2 220 25 13 9.3 5.1
29000 -34.7 -30.5 215 28 14 7.3 4.0 | -35.2 -31.4 225 24 12 9.3 5.1
28000 -32.5 -26.5 215 29 15 7.3 4.0 | -32.4 -26.3 230 23 12 9.3 5.1
27000 -30.2 -22.4 215 27 14 8.1 4.5 | -29.8 -21.6 230 22 11 7.9 4.3
26000 -27.7 -17.9 220 24 12 8.1 4.5 | -27.4 -17.3 225 22 11 7.9 4.3
25000 -25.3 -13.5 220 21 11 8.1 4.5 | -25.1 -13.2 215 22 11 8.0 4.4
24000 -22.9 -9.2 220 18 9 8.3 4.5 | -22.9 -9.2 210 22 12 6.0 3.3
23000 -20.4 -4.7 225 17 8 8.3 4.5 | -21.1 -6.0 210 22 11 6.1 3.3
22000 -17.9 -0.2 225 15 8 8.3 4.5 | -19.3 -2.7 210 21 11 6.1 3.3
21000 -15.5 4.1 230 14 7 7.9 4.3 | -17.2 1.0 210 20 10 9.6 5.3
20000 -12.5 9.5 230 16 8 8.0 4.4 | -13.7 7.3 210 19 10 9.3 5.1
19500 -11.4 11.5 230 16 8 8.0 4.4 | -12.3 9.9 215 18 9 9.3 5.1
19000 -10.2 13.6 230 17 9 8.1 4.5 | -10.9 12.4 215 18 9 9.2 5.1
18500 -8.9 16.0 230 17 9 8.6 4.7 | -9.5 14.9 215 17 9 9.1 5.0
18000 -7.6 18.3 230 16 8 8.6 4.7 | -8.2 17.2 215 17 9 9.1 5.0
17500 -6.4 20.5 230 16 8 8.2 4.5 | -6.9 19.6 210 17 9 8.6 4.7
17000 -5.2 22.6 230 16 8 8.1 4.4 | -5.6 21.9 210 16 8 8.4 4.6
16500 -4.0 24.8 230 15 8 7.9 4.3 | -4.4 24.1 205 16 8 8.4 4.6
16000 -2.9 26.8 220 15 8 7.5 4.1 | -3.1 26.4 205 17 9 8.2 4.5
15500 -1.7 28.9 205 17 8 7.5 4.1 | -1.9 28.6 200 18 9 8.4 4.6
15000 -0.6 30.9 200 17 9 7.9 4.3 | -0.8 30.6 195 18 9 6.7 3.7
14500 0.6 33.1 195 16 8 7.9 4.3 | 0.3 32.5 195 15 8 6.8 3.7
14000 1.7 35.1 195 15 8 7.3 4.0 | 1.3 34.3 195 13 6 6.8 3.8
13500 2.8 37.0 205 14 7 7.3 4.0 | 2.3 36.1 205 11 6 7.1 3.9
13000 3.8 38.8 210 13 7 9.7 5.3 | 3.4 38.1 220 11 5 10.3 5.7
12500 5.1 41.2 200 14 7 5.6 3.0 | 4.6 40.3 235 12 6 3.9 2.2
12000 6.0 42.8 195 15 8 7.8 4.3 | 5.3 41.5 255 14 7 5.5 3.0
11750 6.7 44.1 195 15 8 10.0 5.5 | 5.8 42.4 260 15 8 6.8 3.7
11500 7.4 45.3 195 15 7 7.8 4.3 | 6.3 43.3 260 16 8 7.2 4.0
11250 7.9 46.2 200 14 7 6.8 3.7 | 6.8 44.2 265 17 9 7.3 4.0
11000 8.4 47.1 200 13 7 6.9 3.8 | 7.3 45.1 265 18 9 7.7 4.2
10750 8.9 48.0 210 12 6 6.7 3.7 | 7.9 46.2 265 18 9 8.3 4.5
10500 9.3 48.7 220 12 6 6.0 3.3 | 8.5 47.3 265 16 8 9.1 5.0
10250 9.7 49.5 230 12 6 4.9 2.7 | 9.2 48.6 265 16 8 10.3 5.7
10000 10.1 50.2 240 14 7 4.0 2.2 | 10.0 50.0 265 15 8 10.4 5.7
9750 10.3 50.5 245 16 8 3.2 1.7 | 10.8 51.4 265 15 8 9.9 5.4
9500 10.6 51.1 255 18 9 2.9 1.6 | 11.5 52.7 265 15 8 9.5 5.2
9250 10.8 51.4 260 21 11 2.8 1.5 | 12.2 54.0 265 15 8 10.5 5.8
9000 11.0 51.8 260 23 12 4.1 2.2 | 13.1 55.6 265 15 7 11.3 6.2
8750 11.4 52.5 265 24 13 6.1 3.3 | 13.9 57.0 265 14 7 10.3 5.7
8500 11.9 53.4 265 24 13 6.7 3.7 | 14.6 58.3 265 14 7 10.8 5.9
8250 12.3 54.1 265 24 13 5.8 3.2 | 15.4 59.7 265 14 7 8.8 4.9
8000 12.8 55.0 270 23 12 11.2 6.2 | 16.1 61.0 265 13 7 13.4 7.3
7750 14.1 57.4 270 19 10 22.8 12.5 | 17.6 63.7 265 12 6 27.7 15.2
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
05/13/2025 at 1500 MDT | 05/13/2025 at 1800 MDT
|
CAPE... +1.8 LI... +1.2 | CAPE... +41.0 LI... -0.5
CINH... -10.4 K Index... +10.3 | CINH... -11.1 K Index... +21.5
|
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 -61.6 -78.9 235 38 19 -1.0 -0.5 | -60.3 -76.5 245 41 21 -1.1 -0.6
45000 -62.6 -80.7 240 53 27 2.4 1.3 | -61.7 -79.1 245 57 29 0.7 0.4
40000 -58.9 -74.0 255 28 14 2.4 1.3 | -60.6 -77.1 245 30 15 0.6 0.3
38000 -55.7 -68.3 260 27 14 6.0 3.3 | -56.9 -70.4 250 30 15 7.8 4.3
36000 -52.1 -61.8 260 27 14 6.0 3.3 | -52.2 -62.0 255 33 17 7.8 4.3
34000 -47.5 -53.5 260 27 14 7.6 4.2 | -46.9 -52.4 260 34 18 7.9 4.3
32000 -43.0 -45.4 265 25 13 7.7 4.2 | -42.2 -44.0 255 33 17 7.9 4.3
30000 -38.0 -36.4 265 25 13 9.0 4.9 | -37.4 -35.3 250 29 15 8.4 4.6
29000 -35.3 -31.5 265 26 13 9.0 4.9 | -34.8 -30.6 250 26 13 8.4 4.6
28000 -32.6 -26.7 265 27 14 9.0 4.9 | -32.3 -26.1 250 23 12 8.4 4.6
27000 -30.1 -22.2 265 28 14 7.7 4.2 | -29.8 -21.6 250 22 12 8.6 4.7
26000 -27.8 -18.0 265 28 14 7.7 4.2 | -27.2 -17.0 255 25 13 8.6 4.7
25000 -25.5 -13.9 260 28 14 7.8 4.3 | -24.7 -12.5 260 28 15 8.6 4.7
24000 -23.3 -9.9 260 28 14 7.3 4.0 | -22.2 -8.0 260 31 16 6.8 3.7
23000 -21.1 -6.0 260 28 14 7.3 4.0 | -20.2 -4.4 260 34 17 6.8 3.7
22000 -18.9 -2.0 260 27 14 7.4 4.0 | -18.1 -0.6 260 36 19 6.9 3.8
21000 -16.6 2.1 260 27 14 8.7 4.8 | -16.1 3.0 260 36 18 6.8 3.7
20000 -13.4 7.9 260 26 13 8.6 4.7 | -13.7 7.3 260 27 14 7.1 3.9
19500 -12.1 10.2 260 25 13 8.6 4.7 | -12.7 9.1 260 23 12 7.3 4.0
19000 -10.8 12.6 260 25 13 8.5 4.7 | -11.7 10.9 255 19 10 7.9 4.3
18500 -9.6 14.7 260 24 13 8.1 4.5 | -10.4 13.3 255 17 9 9.6 5.3
18000 -8.4 16.9 260 24 13 8.2 4.5 | -9.0 15.8 255 15 8 9.6 5.2
17500 -7.2 19.0 260 24 12 7.6 4.2 | -7.6 18.3 255 14 7 9.3 5.1
17000 -6.1 21.0 260 24 12 7.5 4.1 | -6.2 20.8 255 14 7 9.3 5.1
16500 -5.0 23.0 260 23 12 7.8 4.3 | -4.8 23.4 250 13 7 9.3 5.1
16000 -3.8 25.2 260 21 11 8.7 4.8 | -3.4 25.9 250 13 7 9.3 5.1
15500 -2.5 27.5 255 18 9 8.6 4.7 | -2.0 28.4 245 13 7 9.3 5.1
15000 -1.2 29.8 250 17 8 9.2 5.0 | -0.6 30.9 240 13 6 9.8 5.4
14500 0.1 32.2 250 16 8 9.1 5.0 | 0.9 33.6 240 13 6 9.7 5.3
14000 1.5 34.7 255 14 7 9.5 5.2 | 2.3 36.1 235 13 6 9.7 5.3
13500 2.9 37.2 250 13 7 9.8 5.4 | 3.8 38.8 230 13 7 9.9 5.4
13000 4.3 39.7 250 12 6 12.8 7.0 | 5.2 41.4 230 13 7 13.1 7.2
12500 6.0 42.8 250 11 6 7.3 4.0 | 6.9 44.4 225 13 7 6.8 3.7
12000 7.2 45.0 245 11 6 9.4 5.2 | 8.1 46.6 220 13 7 8.3 4.6
11750 8.0 46.4 245 11 6 10.8 5.9 | 8.7 47.7 220 14 7 9.4 5.2
11500 8.8 47.8 245 11 6 9.5 5.2 | 9.4 48.9 215 14 7 9.3 5.1
11250 9.5 49.1 245 11 5 9.3 5.1 | 10.1 50.2 215 14 7 9.2 5.1
11000 10.2 50.4 245 10 5 9.4 5.2 | 10.8 51.4 210 14 7 9.2 5.1
10750 10.9 51.6 245 10 5 9.3 5.1 | 11.5 52.7 210 14 7 8.9 4.9
10500 11.6 52.9 245 10 5 9.7 5.3 | 12.2 54.0 205 15 7 9.5 5.2
10250 12.3 54.1 245 10 5 10.2 5.6 | 12.9 55.2 205 15 8 10.4 5.7
10000 13.1 55.6 245 10 5 10.1 5.6 | 13.7 56.7 200 15 8 10.2 5.6
9750 13.8 56.8 245 10 5 9.9 5.4 | 14.4 57.9 200 15 8 9.5 5.2
9500 14.6 58.3 245 10 5 9.6 5.3 | 15.1 59.2 200 15 8 8.6 4.7
9250 15.3 59.5 245 9 5 10.2 5.6 | 15.8 60.4 195 15 8 10.2 5.6
9000 16.1 61.0 245 9 5 10.7 5.9 | 16.6 61.9 195 15 8 11.3 6.2
8750 16.9 62.4 245 9 5 10.4 5.7 | 17.4 63.3 195 15 8 10.2 5.6
8500 17.6 63.7 240 9 4 10.8 5.9 | 18.1 64.6 190 15 8 10.1 5.5
8250 18.4 65.1 240 8 4 9.4 5.2 | 18.9 66.0 190 15 8 9.4 5.2
8000 19.1 66.4 240 8 4 12.3 6.7 | 19.6 67.3 190 14 7 9.6 5.3
7750 20.4 68.7 240 7 4 23.2 12.7 | 20.4 68.7 190 13 7 13.6 7.5
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.
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