Soaring Guidance
Issued by NWS Pueblo, CO
Issued by NWS Pueblo, CO
957
UXUS97 KPUB 091312
SRGPUB
Soaring Forecast
National Weather Service Pueblo, Colorado
0612 MST Saturday, November 9, 2024
This forecast is for the Air Force Academy for Saturday, November 9, 2024:
If the trigger temperature of 41.1 F/5.1 C is reached...then
Thermal Soaring Index....................... Poor
Maximum rate of lift........................ 0 ft/min (0.0 m/s)
Maximum height of thermals.................. 12004 ft MSL (4412 ft AGL)
Forecast maximum temperature................... 43.0 F/6.6 C
Time of trigger temperature.................... 1145 MST
Time of overdevelopment........................ None
Middle/high clouds during soaring window....... Broken/overcast opaque middle
Surface winds during soaring window............ 20 mph or less
Height of the -3 thermal index................. 10750 ft MSL (3158 ft AGL)
Thermal soaring outlook for Sunday 11/10....... Poor
Wave Soaring Index............................. Not available
Remarks...
Sunrise/Sunset.................... 06:36:23 / 16:49:52 MST
Total possible sunshine........... 10 hr 13 min 30 sec (613 min 30 sec)
Altitude of sun at 11:43:08 MST... 33.72 degrees
Upper air data from numerical model forecast valid on 11/09/2024 at 0500 MST
Freezing level.................. Entire airmass below 32 F / 0 C
Convective condensation level... 14704 ft MSL (7112 ft AGL)
Lifted condensation level....... 12616 ft MSL (5024 ft AGL)
Lifted index.................... +8.6
K index......................... +13.1
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 -61.6 -78.9 240 25 13 3.1 1.7 M M M M M
45000 -56.1 -69.0 245 29 15 7.4 4.1 M M M M M
40000 -44.3 -47.7 260 31 16 7.4 4.1 M M M M M
38000 -39.8 -39.6 265 35 18 7.5 4.1 M M M M M
36000 -35.3 -31.5 265 40 21 7.5 4.1 M M M M M
34000 -31.7 -25.1 265 41 21 2.3 1.2 M M M M M
32000 -30.4 -22.7 280 33 17 2.2 1.2 M M M M M
30000 -29.6 -21.3 305 29 15 -3.5 -1.9 43.5 110.3 28.8 M M
29000 -30.5 -22.9 320 28 15 -2.9 -1.6 38.4 101.1 25.2 M M
28000 -31.3 -24.3 340 30 16 -2.9 -1.6 33.6 92.4 21.6 M M
27000 -32.2 -26.0 350 34 18 -3.3 -1.8 28.9 84.0 18.2 M M
26000 -32.1 -25.8 355 38 19 2.3 1.3 25.4 77.7 15.6 M M
25000 -31.4 -24.5 355 41 21 2.4 1.3 22.6 72.7 13.5 M M
24000 -30.7 -23.3 350 44 23 2.5 1.4 20.0 67.9 11.4 M M
23000 -28.5 -19.3 350 45 23 8.2 4.5 18.2 64.8 10.1 M M
22000 -26.1 -15.0 350 45 23 8.1 4.5 17.6 63.7 9.7 M M
21000 -23.7 -10.7 350 44 23 8.0 4.4 17.1 62.8 9.3 M M
20000 -21.4 -6.5 350 41 21 7.8 4.3 16.4 61.5 8.8 M M
19500 -20.2 -4.4 350 39 20 7.8 4.3 16.0 60.9 8.5 M M
19000 -19.1 -2.4 350 38 19 7.8 4.3 15.7 60.3 8.3 M M
18500 -17.9 -0.2 350 36 19 7.7 4.2 15.4 59.8 8.0 M M
18000 -16.8 1.8 350 34 17 6.9 3.8 15.0 59.0 7.7 M M
17500 -15.8 3.6 350 32 16 6.9 3.8 14.5 58.2 7.3 M M
17000 -14.8 5.4 350 30 15 7.3 4.0 14.1 57.4 6.9 M M
16500 -13.7 7.3 350 27 14 7.4 4.0 13.7 56.6 6.5 M M
16000 -12.6 9.3 350 25 13 7.4 4.0 13.3 56.0 6.2 M M
15500 -11.5 11.3 350 25 13 7.4 4.0 12.9 55.2 5.8 M M
15000 -10.5 13.1 345 24 12 7.3 4.0 12.5 54.5 5.5 M M
14500 -9.5 14.9 350 25 13 5.8 3.2 12.0 53.6 5.0 M M
14000 -8.7 16.3 350 26 14 6.4 3.5 11.4 52.5 4.4 M M
13500 -8.0 17.6 350 28 15 2.1 1.2 10.5 50.9 3.6 M M
13000 -7.7 18.1 350 31 16 2.6 1.4 9.3 48.8 2.5 M M
12500 -7.4 18.7 345 33 17 1.0 0.5 8.1 46.5 1.4 M M
12000 -7.2 19.0 340 36 19 0.9 0.5 6.7 44.0 0.1 M M
11750 -7.1 19.2 335 38 19 1.6 0.9 6.0 42.8 -0.6 357 1.8
11500 -7.0 19.4 335 39 20 2.5 1.4 5.4 41.8 -1.1 345 1.8
11250 -6.8 19.8 335 39 20 2.2 1.2 4.8 40.7 -1.7 332 1.7
11000 -6.6 20.1 335 40 20 1.9 1.0 4.2 39.6 -2.3 321 1.6
10750 -6.5 20.3 335 40 21 2.2 1.2 3.6 38.5 -2.9 309 1.6
10500 -6.3 20.7 335 40 20 2.5 1.4 3.1 37.5 -3.5 297 1.5
10250 -6.2 20.8 335 39 20 2.5 1.4 2.5 36.5 -4.0 284 1.4
10000 -6.0 21.2 335 38 20 2.2 1.2 1.9 35.5 -4.6 272 1.4
9750 -5.8 21.6 335 37 19 3.0 1.7 1.4 34.4 -5.2 259 1.3
9500 -5.5 22.1 335 36 19 4.0 2.2 0.9 33.6 -5.7 244 1.2
9250 -5.3 22.5 340 35 18 3.8 2.1 0.4 32.8 -6.1 228 1.2
9000 -5.0 23.0 340 35 18 4.1 2.2 -0.0 32.0 -6.6 212 1.1
8750 -4.6 23.7 340 34 17 5.2 2.8 -0.4 31.3 -7.0 195 1.0
8500 -4.2 24.4 340 31 16 5.9 3.2 -0.7 30.7 -7.3 175 0.9
8250 -3.8 25.2 335 29 15 5.7 3.1 -1.0 30.2 -7.7 155 0.8
8000 -3.4 25.9 335 27 14 6.3 3.5 -1.3 29.7 -8.0 135 0.7
7750 -2.9 26.8 330 20 10 7.3 4.0 -1.5 29.3 -8.2 112 0.6
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 * * * * * *
11/09/2024 at 0800 MST | 11/09/2024 at 1100 MST
|
CAPE... 0.0 LI... +2.6 | CAPE... 0.0 LI... +2.3
CINH... -0.5 K Index... +9.6 | 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 -61.1 -78.0 220 29 15 2.7 1.5 | -60.4 -76.7 210 37 19 2.9 1.6
45000 -56.3 -69.3 230 35 18 6.8 3.7 | -55.5 -67.9 215 35 18 5.6 3.1
40000 -45.6 -50.1 240 32 16 6.8 3.7 | -46.7 -52.1 225 33 17 5.6 3.1
38000 -41.4 -42.5 250 35 18 7.1 3.9 | -43.0 -45.4 235 32 16 6.2 3.4
36000 -37.1 -34.8 255 39 20 7.1 3.9 | -39.3 -38.7 250 31 16 6.2 3.4
34000 -33.7 -28.7 265 39 20 2.6 1.5 | -36.4 -33.5 265 30 15 2.0 1.1
32000 -32.2 -26.0 285 32 16 2.6 1.4 | -35.2 -31.4 285 26 13 2.8 1.1
30000 -31.1 -24.0 305 30 15 -2.3 -1.2 | -34.0 -29.2 315 28 15 2.2 1.2
29000 -31.7 -25.1 315 33 17 -1.9 -1.1 | -33.3 -27.9 325 32 17 2.2 1.2
28000 -32.2 -26.0 325 37 19 -1.9 -1.1 | -32.7 -26.9 330 37 19 2.2 1.2
27000 -32.8 -27.0 330 42 22 -2.6 -1.5 | -32.0 -25.6 335 42 22 2.2 1.2
26000 -32.0 -25.6 330 44 23 4.8 2.6 | -30.8 -23.4 340 44 23 4.5 2.5
25000 -30.5 -22.9 330 46 24 4.8 2.6 | -29.5 -21.1 340 45 23 4.5 2.5
24000 -29.1 -20.4 330 48 25 4.7 2.6 | -28.1 -18.6 340 46 24 4.4 2.4
23000 -26.8 -16.2 330 46 24 7.3 4.0 | -26.4 -15.5 340 46 24 6.5 3.6
22000 -24.6 -12.3 335 43 22 7.3 4.0 | -23.9 -11.0 345 43 22 6.5 3.6
21000 -22.5 -8.5 335 40 21 7.0 3.9 | -22.0 -7.6 345 41 21 6.4 3.5
20000 -20.4 -4.7 335 37 19 6.7 3.7 | -20.1 -4.2 345 38 19 6.3 3.5
19500 -19.4 -2.9 340 35 18 6.7 3.7 | -19.2 -2.6 345 36 18 6.3 3.5
19000 -18.4 -1.1 340 34 18 6.7 3.7 | -18.2 -0.8 340 34 18 6.4 3.5
18500 -17.4 0.7 340 33 17 6.5 3.6 | -17.3 0.9 340 32 17 6.4 3.5
18000 -16.6 2.1 340 31 16 5.5 3.0 | -16.4 2.5 340 31 16 6.4 3.5
17500 -15.8 3.6 345 29 15 5.6 3.1 | -15.4 4.3 340 29 15 6.4 3.5
17000 -14.9 5.2 345 28 14 5.7 3.1 | -14.5 5.9 340 28 14 6.8 3.7
16500 -14.1 6.6 345 26 13 5.7 3.1 | -13.5 7.7 340 27 14 6.8 3.7
16000 -13.3 8.1 350 25 13 6.0 3.3 | -12.5 9.5 340 26 13 7.0 3.8
15500 -12.3 9.9 350 24 12 6.4 3.5 | -11.4 11.5 335 25 13 7.1 3.9
15000 -11.3 11.7 350 23 12 6.5 3.6 | -10.4 13.3 335 24 13 7.2 3.9
14500 -10.3 13.5 350 22 11 7.1 3.9 | -9.3 15.3 330 24 12 7.3 4.0
14000 -9.3 15.3 350 21 11 7.2 3.9 | -8.2 17.2 330 23 12 7.4 4.1
13500 -8.4 16.9 345 21 11 5.8 3.2 | -7.0 19.4 330 23 12 8.5 4.7
13000 -7.5 18.5 345 22 12 6.0 3.3 | -5.7 21.7 325 22 11 8.7 4.8
12500 -6.8 19.8 345 24 12 2.2 1.2 | -4.3 24.3 325 22 12 7.2 4.0
12000 -6.7 19.9 340 28 15 0.8 0.4 | -3.6 25.5 325 23 12 5.5 3.0
11750 -6.7 19.9 335 31 16 0.6 0.3 | -3.3 26.1 320 24 12 3.7 2.0
11500 -6.6 20.1 335 32 17 1.4 0.7 | -3.1 26.4 320 25 13 1.9 1.1
11250 -6.5 20.3 335 34 17 2.8 1.5 | -3.0 26.6 320 26 13 2.0 1.1
11000 -6.2 20.8 330 35 18 3.4 1.9 | -2.8 27.0 320 27 14 1.9 1.0
10750 -6.0 21.2 330 36 19 2.5 1.4 | -2.7 27.1 320 27 14 1.9 1.0
10500 -5.9 21.4 330 36 18 0.6 0.4 | -2.6 27.3 320 27 14 1.2 0.7
10250 -5.8 21.6 325 35 18 3.0 1.6 | -2.5 27.5 320 28 14 3.3 1.8
10000 -5.5 22.1 325 35 18 5.3 2.9 | -2.1 28.2 320 27 14 5.2 2.8
9750 -5.1 22.8 325 34 17 5.7 3.1 | -1.7 28.9 320 27 14 4.9 2.7
9500 -4.7 23.5 325 33 17 6.5 3.6 | -1.4 29.5 320 26 13 4.9 2.7
9250 -4.2 24.4 325 32 17 6.4 3.5 | -1.0 30.2 315 25 13 5.9 3.3
9000 -3.7 25.3 330 31 16 6.6 3.6 | -0.5 31.1 315 24 12 8.0 4.4
8750 -3.2 26.2 325 30 15 6.3 3.5 | 0.1 32.2 315 22 11 7.1 3.9
8500 -2.8 27.0 325 28 14 6.2 3.4 | 0.5 32.9 315 20 10 6.1 3.3
8250 -2.3 27.9 325 26 13 6.0 3.3 | 0.9 33.6 315 18 9 6.4 3.5
8000 -1.9 28.6 325 23 12 7.1 3.9 | 1.4 34.5 315 15 8 7.8 4.3
7750 -1.3 29.7 320 17 9 9.6 5.3 | 2.0 35.6 320 12 6 10.1 5.6
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
11/09/2024 at 1400 MST | 11/09/2024 at 1700 MST
|
CAPE... +0.2 LI... +2.6 | CAPE... 0.0 LI... +2.6
CINH... -0.1 K Index... +14.1 | CINH... 0.0 K Index... +15.2
|
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 -59.9 -75.8 235 38 19 2.9 1.6 | -60.1 -76.2 250 41 21 3.5 1.9
45000 -55.1 -67.2 235 36 19 5.6 3.1 | -54.7 -66.5 255 43 22 4.5 2.5
40000 -46.6 -51.9 245 37 19 5.6 3.1 | -48.0 -54.4 260 42 21 4.4 2.4
38000 -44.1 -47.4 255 35 18 3.0 1.7 | -47.0 -52.6 265 40 20 0.3 0.2
36000 -42.3 -44.1 265 34 18 3.0 1.7 | -46.8 -52.2 280 38 20 0.3 0.2
34000 -40.7 -41.3 285 33 17 1.7 0.9 | -45.7 -50.3 290 37 19 4.2 2.3
32000 -39.7 -39.5 315 33 17 1.7 0.9 | -43.2 -45.8 300 35 18 4.2 2.3
30000 -38.0 -36.4 335 42 22 6.2 3.4 | -39.7 -39.5 315 35 18 9.1 5.0
29000 -36.1 -33.0 340 48 25 6.4 3.5 | -37.0 -34.6 320 38 19 9.1 5.0
28000 -34.2 -29.6 340 53 27 6.4 3.5 | -34.3 -29.7 325 40 21 9.1 5.0
27000 -32.3 -26.1 345 59 30 6.5 3.6 | -31.6 -24.9 330 43 22 8.7 4.8
26000 -30.3 -22.5 340 57 29 6.6 3.6 | -29.0 -20.2 330 44 23 8.5 4.7
25000 -28.4 -19.1 335 55 28 6.6 3.6 | -26.5 -15.7 330 45 23 8.5 4.7
24000 -26.4 -15.5 335 53 27 6.8 3.7 | -24.0 -11.2 335 46 24 8.2 4.5
23000 -24.7 -12.5 330 49 25 5.6 3.1 | -21.8 -7.2 335 45 23 7.1 3.9
22000 -22.6 -8.7 325 42 22 5.6 3.1 | -19.7 -3.5 335 43 22 7.1 3.9
21000 -20.9 -5.6 315 38 20 6.8 3.7 | -17.2 1.0 330 41 21 4.2 2.3
20000 -18.8 -1.8 315 36 18 7.0 3.9 | -15.9 3.4 330 38 20 4.6 2.5
19500 -17.7 0.1 315 34 18 7.0 3.9 | -15.2 4.6 330 36 19 4.6 2.5
19000 -16.7 1.9 315 33 17 7.1 3.9 | -14.6 5.7 330 35 18 4.6 2.5
18500 -15.7 3.7 315 32 16 7.0 3.9 | -13.9 7.0 330 33 17 4.4 2.4
18000 -14.6 5.7 315 31 16 7.0 3.8 | -13.3 8.1 330 31 16 4.4 2.4
17500 -13.6 7.5 310 31 16 7.0 3.9 | -12.6 9.3 335 30 15 4.7 2.6
17000 -12.6 9.3 310 30 15 6.6 3.6 | -11.8 10.8 330 31 16 6.4 3.5
16500 -11.6 11.1 305 29 15 6.6 3.6 | -10.9 12.4 330 33 17 6.4 3.5
16000 -10.5 13.1 300 27 14 6.9 3.8 | -10.0 14.0 330 35 18 5.3 2.9
15500 -9.5 14.9 300 26 13 7.0 3.8 | -9.2 15.4 330 37 19 5.3 2.9
15000 -8.4 16.9 295 24 13 6.9 3.8 | -8.5 16.7 330 39 20 5.3 2.9
14500 -7.4 18.7 290 23 12 6.9 3.8 | -7.7 18.1 330 40 20 5.3 2.9
14000 -6.4 20.5 285 21 11 6.4 3.5 | -7.0 19.4 330 40 21 5.1 2.8
13500 -5.8 21.6 295 22 11 3.3 1.8 | -6.3 20.7 330 40 21 4.6 2.5
13000 -5.3 22.5 305 25 13 3.5 1.9 | -5.6 21.9 330 39 20 4.8 2.6
12500 -4.7 23.5 305 26 13 4.7 2.6 | -4.9 23.2 330 39 20 4.6 2.5
12000 -4.0 24.8 310 28 14 4.3 2.4 | -4.2 24.4 335 36 19 4.7 2.6
11750 -3.7 25.3 315 29 15 6.5 3.6 | -3.9 25.0 335 35 18 5.0 2.7
11500 -3.1 26.4 315 28 14 6.7 3.6 | -3.5 25.7 335 34 18 6.6 3.6
11250 -2.8 27.0 310 27 14 4.4 2.4 | -2.9 26.8 335 34 17 8.2 4.5
11000 -2.5 27.5 310 25 13 4.3 2.3 | -2.3 27.9 335 33 17 8.1 4.4
10750 -2.1 28.2 305 24 12 5.9 3.3 | -1.7 28.9 335 32 17 8.1 4.4
10500 -1.6 29.1 305 22 11 7.3 4.0 | -1.0 30.2 330 32 16 7.9 4.3
10250 -1.1 30.0 300 20 10 8.3 4.6 | -0.4 31.3 330 32 16 8.7 4.8
10000 -0.4 31.3 300 19 10 9.6 5.3 | 0.3 32.5 325 31 16 9.1 5.0
9750 0.2 32.4 295 18 9 6.1 3.4 | 0.9 33.6 325 30 15 8.2 4.5
9500 0.5 32.9 295 17 9 3.3 1.8 | 1.5 34.7 320 28 15 7.7 4.2
9250 0.8 33.4 295 16 8 5.7 3.1 | 2.1 35.8 320 27 14 8.6 4.7
9000 1.4 34.5 295 14 7 7.5 4.1 | 2.7 36.9 315 24 13 7.2 4.0
8750 1.8 35.2 300 12 6 4.1 2.3 | 3.2 37.8 310 22 11 5.4 3.0
8500 1.9 35.4 300 11 6 1.8 1.0 | 3.5 38.3 310 20 10 1.7 0.9
8250 2.1 35.8 305 9 5 2.9 1.6 | 3.8 38.8 305 18 9 14.2 7.8
8000 2.3 36.1 310 7 4 4.5 2.5 | 4.9 40.8 300 16 8 0.5 0.3
7750 2.6 36.7 325 5 3 5.8 3.2 | 2.6 36.7 295 11 6 -58.3 -32.0
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
________________________________________________________________________________
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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