Soaring Guidance
Issued by NWS Pueblo, CO
Issued by NWS Pueblo, CO
269
UXUS97 KPUB 241214
SRGPUB
Soaring Forecast
National Weather Service Pueblo, Colorado
0614 MDT Monday, March 24, 2025
This forecast is for the Air Force Academy for Monday, March 24, 2025:
If the trigger temperature of 55.9 F/13.3 C is reached...then
Thermal Soaring Index....................... Excellent
Maximum rate of lift........................ 1161 ft/min (5.9 m/s)
Maximum height of thermals.................. 20816 ft MSL (13210 ft AGL)
Forecast maximum temperature................... 68.0 F/20.5 C
Time of trigger temperature.................... 1030 MDT
Time of overdevelopment........................ None
Middle/high clouds during soaring window....... Overcast thin high
Surface winds during soaring window............ 20 mph or less
Height of the -3 thermal index................. 16615 ft MSL (9009 ft AGL)
Thermal soaring outlook for Tuesday 03/25...... Excellent
Wave Soaring Index............................. Not available
Remarks...
Sunrise/Sunset.................... 06:55:25 / 19:15:18 MDT
Total possible sunshine........... 12 hr 19 min 53 sec (739 min 53 sec)
Altitude of sun at 13:05:21 MDT... 52.74 degrees
Upper air data from numerical model forecast valid on 03/24/2025 at 0600 MDT
Freezing level.................. 12278 ft MSL (4672 ft AGL)
Convective condensation level... 17361 ft MSL (9755 ft AGL)
Lifted condensation level....... 18530 ft MSL (10924 ft AGL)
Lifted index.................... -2.5
K index......................... +8.9
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 -60.7 -77.3 315 34 18 -0.6 -0.3 M M M M M
45000 -61.6 -78.9 315 41 21 -0.8 -0.5 M M M M M
40000 -64.5 -84.1 345 41 21 -1.9 -1.0 M M M M M
38000 -63.0 -81.4 350 47 24 6.7 3.7 M M M M M
36000 -58.5 -73.3 355 56 29 6.7 3.7 M M M M M
34000 -54.1 -65.4 355 58 30 8.5 4.7 M M M M M
32000 -49.0 -56.2 350 45 23 8.5 4.7 M M M M M
30000 -43.7 -46.7 345 35 18 9.3 5.1 24.3 75.7 3.3 M M
29000 -40.9 -41.6 340 31 16 9.3 5.1 24.0 75.2 3.1 M M
28000 -38.1 -36.6 340 27 14 9.3 5.1 23.9 75.0 3.1 M M
27000 -35.4 -31.7 335 24 12 8.2 4.5 23.7 74.7 3.0 M M
26000 -32.9 -27.2 330 26 13 8.2 4.5 23.1 73.5 2.5 M M
25000 -30.5 -22.9 325 28 14 8.2 4.5 22.5 72.5 2.0 M M
24000 -28.0 -18.4 320 30 16 8.2 4.5 22.1 71.7 1.7 M M
23000 -25.6 -14.1 320 34 17 8.2 4.5 21.4 70.5 1.1 M M
22000 -23.1 -9.6 325 37 19 8.2 4.5 20.9 69.6 0.7 M M
21000 -20.1 -4.2 325 41 21 7.7 4.2 20.2 68.3 0.1 M M
20000 -17.9 -0.2 325 41 21 7.7 4.2 19.4 67.0 -0.6 1170 5.9
19500 -16.7 1.9 325 41 21 7.7 4.3 19.1 66.4 -0.9 1120 5.7
19000 -15.6 3.9 330 42 21 7.7 4.3 18.8 65.9 -1.2 1071 5.4
18500 -14.4 6.1 330 42 21 7.6 4.2 18.5 65.3 -1.5 1022 5.2
18000 -13.3 8.1 330 41 21 7.7 4.2 18.1 64.6 -1.9 973 4.9
17500 -12.2 10.0 330 41 21 7.1 3.9 17.8 64.0 -2.2 925 4.7
17000 -11.2 11.8 330 40 21 6.9 3.8 17.3 63.1 -2.7 880 4.5
16500 -10.2 13.6 330 39 20 7.0 3.9 16.8 62.2 -3.1 835 4.2
16000 -9.0 15.8 330 38 20 7.6 4.2 16.4 61.5 -3.5 787 4.0
15500 -7.9 17.8 330 37 19 7.5 4.1 16.0 60.9 -3.9 739 3.8
15000 -6.7 19.9 330 37 19 8.8 4.8 15.8 60.4 -4.2 688 3.5
14500 -5.4 22.3 330 37 19 8.7 4.8 15.6 60.1 -4.4 634 3.2
14000 -4.2 24.4 330 37 19 8.2 4.5 15.4 59.7 -4.6 582 3.0
13500 -3.0 26.6 330 37 19 8.1 4.4 15.1 59.2 -4.9 531 2.7
13000 -1.7 28.9 330 37 19 9.4 5.1 14.9 58.8 -5.1 479 2.4
12500 -0.5 31.1 330 37 19 6.6 3.6 14.7 58.4 -5.4 427 2.2
12000 0.5 32.9 330 38 20 6.2 3.4 14.2 57.6 -5.9 384 1.9
11750 0.9 33.6 330 40 21 6.0 3.3 13.9 57.0 -6.2 363 1.8
11500 1.3 34.3 330 41 21 5.3 2.9 13.6 56.5 -6.5 343 1.7
11250 1.7 35.1 325 43 22 4.7 2.6 13.2 55.8 -6.9 325 1.7
11000 2.0 35.6 325 46 23 3.4 1.8 12.8 55.0 -7.4 309 1.6
10750 2.1 35.8 320 46 24 1.9 1.0 12.2 54.0 -8.0 297 1.5
10500 2.3 36.1 320 47 24 2.8 1.5 11.6 52.9 -8.6 285 1.4
10250 2.4 36.3 315 49 25 -0.4 -0.2 11.0 51.8 -9.2 274 1.4
10000 2.2 36.0 315 50 26 -0.3 -0.1 10.1 50.3 -10.1 271 1.4
9750 2.4 36.3 310 48 25 2.7 1.5 9.5 49.2 -10.7 260 1.3
9500 2.5 36.5 310 46 24 1.5 0.8 9.0 48.1 -11.4 248 1.3
9250 2.7 36.9 310 44 23 3.5 1.9 8.4 47.1 -12.0 237 1.2
9000 3.0 37.4 305 40 21 4.7 2.6 8.0 46.4 -12.4 220 1.1
8750 3.3 37.9 305 38 19 3.5 1.9 7.5 45.6 -12.9 204 1.0
8500 3.6 38.5 300 35 18 4.3 2.4 7.1 44.7 -13.4 188 1.0
8250 3.8 38.8 300 33 17 2.1 1.2 6.6 43.9 -13.9 172 0.9
8000 3.8 38.8 295 30 15 -3.6 -1.9 5.9 42.5 -14.7 166 0.8
7750 3.4 38.1 295 21 11 -6.5 -3.6 4.7 40.5 -15.9 172 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 * * * * * *
03/24/2025 at 0900 MDT | 03/24/2025 at 1200 MDT
|
CAPE... 0.0 LI... +3.5 | CAPE... 0.0 LI... +1.7
CINH... 0.0 K Index... +4.0 | CINH... 0.0 K Index... +7.4
|
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 -60.8 -77.4 320 32 17 -1.7 -1.0 | -61.0 -77.8 310 30 15 -0.9 -0.5
45000 -63.4 -82.1 325 41 21 -1.8 -1.0 | -62.3 -80.1 320 38 19 -1.1 -0.6
40000 -66.3 -87.3 350 50 26 -2.0 -1.1 | -66.1 -87.0 345 46 24 -2.4 -1.3
38000 -63.6 -82.5 355 51 26 8.2 4.5 | -63.1 -81.6 345 45 23 8.7 4.8
36000 -58.6 -73.5 350 48 25 8.2 4.5 | -57.8 -72.0 350 42 22 8.7 4.8
34000 -53.6 -64.5 350 46 24 8.8 4.8 | -52.8 -63.0 345 40 21 8.0 4.4
32000 -48.3 -54.9 345 42 22 8.8 4.8 | -48.0 -54.4 330 42 22 8.0 4.4
30000 -43.0 -45.4 340 38 19 9.1 5.0 | -42.9 -45.2 325 42 22 9.0 4.9
29000 -40.2 -40.4 335 34 18 9.1 5.0 | -40.3 -40.5 325 41 21 9.0 4.9
28000 -37.5 -35.5 325 31 16 9.1 5.0 | -37.6 -35.7 325 39 20 9.0 4.9
27000 -34.8 -30.6 320 31 16 8.0 4.4 | -34.9 -30.8 325 37 19 8.4 4.6
26000 -32.4 -26.3 320 33 17 8.2 4.5 | -32.4 -26.3 320 38 20 8.5 4.7
25000 -30.0 -22.0 320 36 19 8.2 4.5 | -29.8 -21.6 320 38 20 8.5 4.7
24000 -27.5 -17.5 320 38 20 7.9 4.4 | -27.3 -17.1 320 39 20 7.9 4.3
23000 -25.2 -13.4 320 35 18 7.9 4.3 | -24.4 -11.9 320 38 20 7.8 4.3
22000 -22.2 -8.0 320 31 16 7.9 4.3 | -22.0 -7.6 320 38 19 7.9 4.3
21000 -19.9 -3.8 320 29 15 8.2 4.5 | -19.7 -3.5 320 36 19 7.6 4.1
20000 -17.4 0.7 325 28 15 8.2 4.5 | -17.5 0.5 320 35 18 7.6 4.1
19500 -16.2 2.8 325 28 15 8.2 4.5 | -16.4 2.5 320 34 18 7.6 4.2
19000 -15.0 5.0 325 28 15 8.1 4.5 | -15.2 4.6 320 33 17 7.8 4.3
18500 -13.8 7.2 325 28 14 8.0 4.4 | -14.0 6.8 315 32 16 8.2 4.5
18000 -12.6 9.3 325 28 14 8.1 4.4 | -12.8 9.0 315 31 16 8.2 4.5
17500 -11.4 11.5 330 28 14 7.3 4.0 | -11.6 11.1 315 29 15 8.2 4.5
17000 -10.4 13.3 330 27 14 7.2 4.0 | -10.3 13.5 310 28 14 8.2 4.5
16500 -9.3 15.3 330 26 14 7.0 3.9 | -9.1 15.6 310 26 13 8.2 4.5
16000 -8.3 17.1 335 26 13 6.8 3.7 | -7.9 17.8 305 24 12 8.1 4.5
15500 -7.3 18.9 335 25 13 6.8 3.7 | -6.7 19.9 300 22 12 8.1 4.4
15000 -6.3 20.7 340 24 13 6.5 3.6 | -5.5 22.1 300 21 11 7.6 4.2
14500 -5.3 22.5 340 24 12 6.5 3.6 | -4.4 24.1 295 20 10 7.6 4.2
14000 -4.4 24.1 345 23 12 6.9 3.8 | -3.2 26.2 290 17 9 8.4 4.6
13500 -3.3 26.1 345 21 11 6.9 3.8 | -1.9 28.6 270 15 7 8.4 4.6
13000 -2.3 27.9 345 20 10 8.0 4.4 | -0.7 30.7 260 14 7 7.5 4.1
12500 -1.2 29.8 340 18 9 6.0 3.3 | 0.2 32.4 265 13 7 5.7 3.1
12000 -0.3 31.5 340 16 8 6.9 3.8 | 1.0 33.8 265 11 6 5.2 2.9
11750 0.2 32.4 340 17 9 7.0 3.9 | 1.4 34.5 270 11 6 4.9 2.7
11500 0.8 33.4 340 17 9 8.0 4.4 | 1.8 35.2 270 10 5 5.6 3.1
11250 1.4 34.5 340 18 9 9.2 5.1 | 2.2 36.0 280 9 5 6.4 3.5
11000 2.1 35.8 340 20 10 8.5 4.7 | 2.7 36.9 290 9 5 6.4 3.5
10750 2.7 36.9 335 21 11 8.2 4.5 | 3.2 37.8 300 9 5 6.4 3.5
10500 3.3 37.9 335 23 12 8.3 4.6 | 3.7 38.7 310 9 5 6.5 3.6
10250 4.0 39.2 335 24 12 9.4 5.2 | 4.2 39.6 315 10 5 8.1 4.4
10000 4.6 40.3 335 25 13 7.3 4.0 | 4.8 40.6 315 10 5 8.6 4.7
9750 5.0 41.0 325 26 13 4.6 2.5 | 5.3 41.5 305 10 5 8.0 4.4
9500 5.4 41.7 320 27 14 6.3 3.5 | 5.9 42.6 295 10 5 8.3 4.5
9250 5.8 42.4 320 29 15 2.1 1.1 | 6.5 43.7 285 11 5 8.1 4.4
9000 5.6 42.1 315 29 15 -3.5 -1.9 | 7.1 44.8 285 10 5 9.0 4.9
8750 5.4 41.7 310 28 14 -3.0 -1.7 | 7.8 46.0 285 10 5 9.9 5.4
8500 5.1 41.2 300 28 14 -4.2 -2.3 | 8.5 47.3 280 9 5 9.5 5.2
8250 4.8 40.6 295 28 14 0.3 0.1 | 9.2 48.6 275 9 5 10.3 5.7
8000 5.2 41.4 295 24 13 9.4 5.1 | 10.2 50.4 280 9 5 16.5 9.1
7750 6.0 42.8 295 18 9 11.3 6.2 | 11.7 53.1 280 8 4 24.2 13.3
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
03/24/2025 at 1500 MDT | 03/24/2025 at 1800 MDT
|
CAPE... +34.8 LI... +0.1 | CAPE... +18.0 LI... +0.1
CINH... -2.3 K Index... +17.0 | CINH... -21.2 K Index... +17.1
|
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 -61.7 -79.1 315 28 14 -0.6 -0.3 | -62.8 -81.0 310 27 14 -0.9 -0.5
45000 -62.7 -80.9 325 35 18 -1.4 -0.7 | -64.2 -83.6 305 31 16 -1.0 -0.5
40000 -65.1 -85.2 340 39 20 -1.6 -0.9 | -65.7 -86.3 300 33 17 -0.9 -0.5
38000 -62.3 -80.1 330 37 19 8.0 4.4 | -62.4 -80.3 305 35 18 8.5 4.7
36000 -57.5 -71.5 310 36 19 8.0 4.4 | -57.3 -71.1 310 39 20 8.5 4.6
34000 -52.7 -62.9 300 39 20 8.4 4.6 | -52.2 -62.0 310 42 22 8.9 4.9
32000 -47.1 -52.8 305 43 22 8.4 4.6 | -46.2 -51.2 315 46 24 8.9 4.9
30000 -41.9 -43.4 310 46 24 9.0 4.9 | -41.0 -41.8 315 47 24 8.5 4.7
29000 -39.2 -38.6 310 48 25 9.0 5.3 | -38.5 -37.3 315 45 23 8.5 4.7
28000 -36.5 -33.7 310 50 26 9.0 4.9 | -35.9 -32.6 315 44 23 8.5 4.7
27000 -33.9 -29.0 310 51 26 7.9 4.3 | -33.5 -28.3 315 43 22 7.6 4.1
26000 -31.6 -24.9 310 49 25 7.9 4.3 | -31.2 -24.2 310 43 22 7.6 4.2
25000 -29.2 -20.6 310 47 24 7.9 4.4 | -29.0 -20.2 310 42 22 7.6 4.2
24000 -26.9 -16.4 310 46 23 7.4 4.1 | -26.7 -16.1 310 42 22 7.8 4.3
23000 -24.7 -12.5 310 44 22 7.5 4.1 | -24.4 -11.9 310 41 21 7.8 4.3
22000 -22.4 -8.3 310 42 21 7.5 4.1 | -22.1 -7.8 305 41 21 7.8 4.3
21000 -20.2 -4.4 310 40 20 7.8 4.3 | -19.8 -3.6 305 40 20 7.3 4.0
20000 -17.9 -0.2 310 38 20 7.8 4.3 | -17.6 0.3 300 38 20 7.3 4.0
19500 -16.2 2.8 310 37 19 7.8 4.3 | -16.6 2.1 300 37 19 7.3 4.0
19000 -15.0 5.0 310 36 18 7.6 4.2 | -15.0 5.0 300 36 19 7.5 4.1
18500 -13.9 7.0 305 34 18 7.5 4.1 | -13.8 7.2 295 35 18 7.6 4.2
18000 -12.8 9.0 305 33 17 7.5 4.1 | -12.7 9.1 295 34 17 7.7 4.2
17500 -11.7 10.9 305 31 16 7.3 4.0 | -11.6 11.1 295 33 17 7.3 4.0
17000 -10.6 12.9 300 29 15 7.3 4.0 | -10.5 13.1 295 31 16 7.4 4.1
16500 -9.6 14.7 295 27 14 6.9 3.8 | -9.4 15.1 300 30 15 6.9 3.8
16000 -8.6 16.5 290 24 13 6.7 3.7 | -8.5 16.7 295 28 14 6.7 3.7
15500 -7.7 18.1 285 22 12 6.7 3.7 | -7.5 18.5 295 26 13 6.8 3.7
15000 -6.7 19.9 285 19 10 6.8 3.7 | -6.5 20.3 295 24 12 7.2 3.9
14500 -5.7 21.7 285 16 8 6.8 3.7 | -5.5 22.1 290 22 11 7.3 4.0
14000 -4.6 23.7 285 13 6 8.9 4.9 | -4.4 24.1 290 20 10 8.4 4.6
13500 -3.3 26.1 290 10 5 8.7 4.8 | -3.2 26.2 290 17 9 8.4 4.6
13000 -1.9 28.6 290 8 4 9.9 5.4 | -2.0 28.4 295 16 8 7.8 4.3
12500 -0.6 30.9 300 7 4 8.8 4.8 | -0.7 30.7 300 14 7 9.5 5.2
12000 0.7 33.3 310 6 3 8.9 4.9 | 0.5 32.9 300 13 7 7.6 4.2
11750 1.4 34.5 315 6 3 8.7 4.8 | 1.1 34.0 305 13 7 7.3 4.0
11500 2.1 35.8 315 5 3 10.7 5.9 | 1.7 35.1 305 12 6 8.8 4.8
11250 2.9 37.2 320 5 3 11.2 6.1 | 2.4 36.3 310 12 6 9.2 5.0
11000 3.7 38.7 325 5 3 9.0 5.0 | 3.0 37.4 315 12 6 7.8 4.3
10750 4.3 39.7 325 5 3 8.4 4.6 | 3.5 38.3 320 12 6 7.5 4.1
10500 5.0 41.0 330 5 3 9.9 5.4 | 4.1 39.4 330 12 6 8.7 4.8
10250 5.8 42.4 330 5 3 11.9 6.5 | 4.8 40.6 335 12 6 10.6 5.8
10000 6.6 43.9 335 5 3 10.4 5.7 | 5.6 42.1 340 13 6 9.8 5.4
9750 7.4 45.3 335 5 3 9.2 5.1 | 6.3 43.3 345 13 7 8.9 4.9
9500 8.1 46.6 340 5 3 9.6 5.3 | 7.0 44.6 345 13 7 9.5 5.2
9250 8.8 47.8 340 5 3 9.3 5.1 | 7.7 45.9 350 14 7 8.0 4.4
9000 9.5 49.1 345 5 3 10.2 5.6 | 8.2 46.8 350 14 7 8.5 4.7
8750 10.3 50.5 345 5 3 11.0 6.0 | 9.0 48.2 355 14 7 10.4 5.7
8500 11.1 52.0 350 5 3 10.9 6.0 | 9.7 49.5 355 15 8 9.9 5.4
8250 11.9 53.4 350 5 3 10.1 5.5 | 10.4 50.7 355 15 8 10.5 5.8
8000 12.7 54.9 350 5 3 15.0 8.2 | 11.2 52.2 355 14 7 11.5 6.3
7750 14.2 57.6 355 5 3 25.5 14.0 | 12.1 53.8 360 12 6 12.2 6.7
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.
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