Soaring Guidance
Issued by NWS Pueblo, CO
Issued by NWS Pueblo, CO
350
UXUS97 KPUB 191236
SRGPUB
Soaring Forecast
National Weather Service Pueblo, Colorado
0536 MST Sunday, January 19, 2025
This forecast is for the Air Force Academy for Sunday, January 19, 2025:
If the trigger temperature of 15.1 F/-9.4 C is reached...then
Thermal Soaring Index....................... Poor
Maximum rate of lift........................ 0 ft/min (0.0 m/s)
Maximum height of thermals.................. 11584 ft MSL (3976 ft AGL)
Forecast maximum temperature................... 15.0 F/-9.9 C
Time of trigger temperature.................... 1445 MST
Time of overdevelopment........................ None
Middle/high clouds during soaring window....... Broken/overcast opaque middle
Surface winds during soaring window............ Between 20 mph and 30 mph
Height of the -3 thermal index................. 9745 ft MSL (2136 ft AGL)
Thermal soaring outlook for Monday 01/20....... Poor
Wave Soaring Index............................. Not available
Remarks...
Sunrise/Sunset.................... 07:14:31 / 17:05:48 MST
Total possible sunshine........... 9 hr 51 min 17 sec (591 min 17 sec)
Altitude of sun at 12:10:10 MST... 30.81 degrees
Upper air data from numerical model forecast valid on 01/19/2025 at 0500 MST
Freezing level.................. Entire airmass below 32 F / 0 C
Convective condensation level... 21048 ft MSL (13440 ft AGL)
Lifted condensation level....... 14710 ft MSL (7101 ft AGL)
Lifted index.................... +16.3
K index......................... -34.0
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 -53.3 -63.9 295 49 25 1.9 1.0 M M M M M
45000 -50.5 -58.9 295 57 29 1.9 1.0 M M M M M
40000 -50.1 -58.2 295 64 33 -0.1 -0.1 M M M M M
38000 -50.2 -58.4 295 66 34 0.2 0.1 M M M M M
36000 -52.4 -62.3 295 67 35 -3.7 -2.0 M M M M M
34000 -54.6 -66.3 300 68 35 -3.7 -2.0 M M M M M
32000 -54.3 -65.7 300 68 35 3.1 1.7 M M M M M
30000 -52.5 -62.5 295 67 34 3.1 1.7 M M M M M
29000 -51.1 -60.0 295 66 34 7.3 4.0 15.6 60.1 19.3 M M
28000 -49.0 -56.2 300 66 34 7.1 3.9 14.4 58.0 18.6 M M
27000 -46.9 -52.4 300 65 33 7.1 3.9 13.4 56.2 18.1 M M
26000 -44.8 -48.6 300 64 33 7.4 4.0 12.6 54.6 17.6 M M
25000 -42.5 -44.5 305 62 32 7.8 4.3 11.7 53.1 17.1 M M
24000 -40.1 -40.2 305 61 31 7.8 4.3 11.0 51.8 16.7 M M
23000 -37.8 -36.0 305 60 31 7.5 4.1 10.4 50.7 16.4 M M
22000 -35.1 -31.2 310 58 30 7.1 3.9 9.1 48.4 15.6 M M
21000 -33.0 -27.4 310 57 29 7.1 3.9 8.2 46.7 15.0 M M
20000 -31.0 -23.8 310 55 28 6.0 3.3 7.1 44.8 14.3 M M
19500 -30.1 -22.2 310 54 28 6.0 3.3 6.4 43.5 13.8 M M
19000 -29.2 -20.6 310 53 28 6.0 3.3 5.8 42.4 13.3 M M
18500 -28.3 -18.9 310 53 27 5.9 3.3 5.2 41.3 12.8 M M
18000 -27.4 -17.3 310 52 27 5.1 2.8 4.6 40.2 12.4 M M
17500 -26.8 -16.2 310 50 26 3.8 2.1 3.6 38.4 11.6 M M
17000 -26.3 -15.3 310 49 25 3.8 2.1 2.6 36.7 10.8 M M
16500 -25.8 -14.4 315 47 24 2.6 1.4 1.5 34.7 9.8 M M
16000 -25.4 -13.7 315 46 24 2.7 1.5 0.3 32.5 8.8 M M
15500 -25.0 -13.0 315 45 23 3.0 1.6 -0.8 30.5 7.8 M M
15000 -24.5 -12.1 315 44 23 3.0 1.6 -2.0 28.5 6.8 M M
14500 -24.1 -11.4 320 43 22 3.4 1.9 -3.0 26.5 5.9 M M
14000 -23.5 -10.3 320 43 22 3.6 2.0 -4.0 24.7 5.0 M M
13500 -23.0 -9.4 320 43 22 3.4 1.8 -5.0 23.0 4.1 M M
13000 -22.5 -8.5 320 42 22 3.2 1.8 -6.1 21.1 3.1 M M
12500 -22.0 -7.6 320 42 22 3.8 2.1 -7.1 19.2 2.2 M M
12000 -21.7 -7.1 320 41 21 1.2 0.7 -8.2 17.2 1.1 M M
11750 -21.6 -6.9 320 40 20 1.8 1.0 -8.9 16.0 0.5 M M
11500 -21.4 -6.5 320 38 20 3.3 1.8 -9.5 15.0 -0.1 345 1.8
11250 -21.1 -6.0 320 37 19 3.9 2.1 -9.9 14.2 -0.5 329 1.7
11000 -20.8 -5.4 320 35 18 2.8 1.5 -10.4 13.2 -1.0 314 1.6
10750 -20.6 -5.1 320 33 17 3.5 1.9 -11.0 12.3 -1.5 300 1.5
10500 -20.3 -4.5 320 31 16 4.8 2.6 -11.4 11.5 -2.0 284 1.4
10250 -19.9 -3.8 320 28 14 5.1 2.8 -11.8 10.8 -2.3 265 1.3
10000 -19.5 -3.1 320 25 13 5.5 3.0 -12.1 10.2 -2.7 246 1.2
9750 -19.1 -2.4 320 23 12 7.1 3.9 -12.4 9.7 -2.9 225 1.1
9500 -18.5 -1.3 320 20 11 7.9 4.4 -12.5 9.4 -3.1 200 1.0
9250 -17.9 -0.2 315 18 9 7.8 4.3 -12.7 9.2 -3.3 175 0.9
9000 -17.3 0.9 315 16 8 7.2 4.0 -12.8 8.9 -3.4 150 0.8
8750 -16.8 1.8 305 14 7 7.0 3.9 -13.1 8.5 -3.7 127 0.6
8500 -16.3 2.7 300 13 7 8.0 4.4 -13.2 8.2 -3.8 103 0.5
8250 -15.7 3.7 295 13 7 6.3 3.5 -13.4 7.9 -4.0 79 0.4
8000 -15.7 3.7 290 13 6 -10.3 -5.7 -14.1 6.6 -4.7 71 0.4
7750 -17.4 0.7 280 9 5 -32.8 -18.0 -16.6 2.2 -7.2 115 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 * * * * * *
01/19/2025 at 0800 MST | 01/19/2025 at 1100 MST
|
CAPE... 0.0 LI... +6.6 | CAPE... 0.0 LI... +7.1
CINH... 0.0 K Index... -15.8 | CINH... 0.0 K Index... -10.2
|
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 -53.3 -63.9 290 51 26 2.3 1.3 | -54.3 -65.7 290 57 29 2.5 1.4
45000 -49.8 -57.6 295 55 28 2.3 1.3 | -50.6 -59.1 285 58 30 2.5 1.4
40000 -49.2 -56.6 300 61 31 -0.0 -0.0 | -49.5 -57.1 290 63 33 0.3 0.2
38000 -49.2 -56.6 300 64 33 0.4 0.2 | -49.3 -56.7 290 66 34 0.6 0.4
36000 -51.5 -60.7 295 64 33 -4.0 -2.2 | -50.8 -59.4 290 66 34 -2.5 -1.4
34000 -53.9 -65.0 295 63 33 -4.0 -2.2 | -52.3 -62.1 290 65 33 -2.5 -1.4
32000 -54.5 -66.1 290 63 32 1.2 0.6 | -52.6 -62.7 290 65 33 0.9 0.5
30000 -53.8 -64.8 290 62 32 1.1 0.6 | -52.1 -61.8 290 65 34 0.8 0.5
29000 -53.1 -63.6 290 62 32 7.0 3.8 | -51.5 -60.7 290 66 34 5.2 2.9
28000 -51.1 -60.0 290 62 32 6.4 3.5 | -50.1 -58.2 290 66 34 4.7 2.6
27000 -49.2 -56.6 290 61 32 6.4 3.5 | -48.7 -55.7 290 66 34 4.7 2.6
26000 -47.3 -53.1 295 61 32 7.1 3.9 | -47.3 -53.1 290 65 34 5.0 2.7
25000 -44.8 -48.6 295 60 31 8.6 4.7 | -45.5 -49.9 290 64 33 5.9 3.3
24000 -42.2 -44.0 295 58 30 8.6 4.7 | -43.8 -46.8 290 62 32 5.9 3.3
23000 -39.6 -39.3 300 56 29 8.3 4.6 | -42.0 -43.6 290 60 31 6.8 3.7
22000 -36.7 -34.1 300 53 27 7.7 4.2 | -39.3 -38.7 290 57 29 9.3 5.1
21000 -34.4 -29.9 300 50 26 7.7 4.2 | -35.9 -32.6 295 52 27 9.2 5.1
20000 -32.3 -26.1 305 48 25 6.2 3.4 | -33.3 -27.9 295 50 26 8.1 4.4
19500 -31.4 -24.5 305 47 24 6.2 3.4 | -32.0 -25.6 295 48 25 8.1 4.4
19000 -30.4 -22.7 305 45 23 6.2 3.4 | -30.8 -23.4 295 47 24 8.1 4.4
18500 -29.5 -21.1 310 44 23 6.2 3.4 | -29.6 -21.3 300 46 24 8.0 4.4
18000 -28.6 -19.5 310 43 22 5.7 3.1 | -28.4 -19.1 300 44 23 6.8 3.7
17500 -27.8 -18.0 310 42 21 5.1 2.8 | -27.7 -17.9 300 41 21 4.9 2.7
17000 -27.0 -16.6 310 40 21 5.1 2.8 | -26.9 -16.4 300 38 20 4.9 2.7
16500 -26.3 -15.3 315 39 20 4.4 2.4 | -26.3 -15.3 300 35 18 4.3 2.3
16000 -25.6 -14.1 315 38 19 4.5 2.5 | -25.6 -14.1 300 32 17 4.4 2.4
15500 -25.0 -13.0 315 36 19 4.2 2.3 | -25.0 -13.0 300 29 15 4.1 2.2
15000 -24.4 -11.9 320 35 18 4.2 2.3 | -24.4 -11.9 300 26 13 4.1 2.2
14500 -23.7 -10.7 320 33 17 4.5 2.5 | -23.8 -10.8 295 23 12 3.3 1.8
14000 -23.0 -9.4 320 31 16 4.6 2.5 | -23.3 -9.9 295 21 11 3.1 1.7
13500 -22.4 -8.3 325 30 15 4.0 2.2 | -22.8 -9.0 295 18 9 3.9 2.1
13000 -21.8 -7.2 325 28 14 3.7 2.0 | -22.2 -8.0 300 17 9 4.4 2.4
12500 -21.3 -6.3 325 26 14 4.9 2.7 | -21.5 -6.7 305 16 8 4.8 2.6
12000 -20.6 -5.1 325 24 13 3.2 1.7 | -20.9 -5.6 305 15 8 3.5 1.9
11750 -20.4 -4.7 325 23 12 3.5 1.9 | -20.6 -5.1 310 14 7 4.0 2.2
11500 -20.1 -4.2 325 21 11 4.0 2.2 | -20.2 -4.4 310 13 7 6.1 3.4
11250 -19.8 -3.6 325 19 10 3.9 2.1 | -19.7 -3.5 305 11 6 6.4 3.5
11000 -19.5 -3.1 325 17 9 3.0 1.6 | -19.3 -2.7 305 10 5 4.9 2.7
10750 -19.3 -2.7 325 16 8 3.6 2.0 | -19.0 -2.2 300 9 4 5.3 2.9
10500 -19.0 -2.2 320 14 7 4.7 2.6 | -18.5 -1.3 295 8 4 5.6 3.1
10250 -18.6 -1.5 315 12 6 5.0 2.7 | -18.1 -0.6 290 7 3 5.9 3.3
10000 -18.3 -0.9 310 11 5 4.4 2.4 | -17.6 0.3 285 6 3 7.0 3.9
9750 -17.9 -0.2 305 10 5 5.7 3.1 | -17.1 1.2 270 5 3 7.3 4.0
9500 -17.4 0.7 300 8 4 7.1 3.9 | -16.6 2.1 265 5 2 6.9 3.8
9250 -16.9 1.6 290 8 4 6.9 3.8 | -16.1 3.0 260 4 2 6.9 3.8
9000 -16.4 2.5 285 7 3 5.5 3.0 | -15.5 4.1 250 4 2 9.8 5.4
8750 -16.1 3.0 275 7 4 4.8 2.6 | -14.7 5.5 235 3 2 10.7 5.9
8500 -15.7 3.7 270 8 4 6.2 3.4 | -13.9 7.0 230 3 2 10.0 5.5
8250 -15.2 4.6 265 8 4 4.1 2.3 | -13.2 8.2 225 3 2 8.0 4.4
8000 -15.3 4.5 265 9 5 -7.5 -4.1 | -12.6 9.3 215 3 1 11.8 6.5
7750 -16.4 2.5 260 7 4 -21.1 -11.6 | -11.2 11.8 205 3 1 25.4 14.0
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
01/19/2025 at 1400 MST | 01/19/2025 at 1700 MST
|
CAPE... 0.0 LI... +5.6 | CAPE... +0.2 LI... +3.2
CINH... -0.0 K Index... -1.7 | CINH... 0.0 K Index... +4.4
|
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 -53.6 -64.5 295 56 29 2.0 1.1 | -52.4 -62.3 290 53 27 1.2 0.7
45000 -50.4 -58.7 295 60 31 2.0 1.1 | -50.4 -58.7 295 55 28 1.2 0.7
40000 -49.8 -57.6 295 61 31 -0.0 -0.0 | -49.1 -56.4 290 61 32 0.8 0.4
38000 -49.9 -57.8 295 61 31 0.1 0.1 | -48.7 -55.7 290 65 33 1.0 0.5
36000 -50.6 -59.1 290 62 32 -1.5 -0.8 | -49.5 -57.1 290 66 34 -1.8 -1.0
34000 -51.7 -61.1 290 64 33 -1.5 -0.8 | -50.6 -59.1 285 68 35 -1.8 -1.0
32000 -52.0 -61.6 285 68 35 0.3 0.2 | -51.3 -60.3 285 67 35 -0.1 -0.1
30000 -51.8 -61.2 285 72 37 0.2 0.1 | -51.4 -60.5 285 64 33 -0.1 -0.1
29000 -51.5 -60.7 285 74 38 4.9 2.7 | -51.3 -60.3 285 62 32 1.9 1.0
28000 -50.0 -58.0 285 74 38 5.0 2.8 | -50.6 -59.1 290 59 31 2.5 1.4
27000 -48.5 -55.3 285 73 38 5.0 2.8 | -49.9 -57.8 290 56 29 2.5 1.4
26000 -47.0 -52.6 285 73 38 5.1 2.8 | -49.1 -56.4 295 54 28 2.0 1.1
25000 -45.2 -49.4 285 70 36 6.0 3.3 | -47.6 -53.7 295 51 26 6.2 3.4
24000 -43.4 -46.1 290 66 34 6.0 3.3 | -45.7 -50.3 295 49 25 6.2 3.4
23000 -41.6 -42.9 290 62 32 6.1 3.3 | -43.9 -47.0 295 47 24 6.1 3.4
22000 -39.6 -39.3 290 57 29 6.7 3.7 | -41.6 -42.9 290 45 23 8.1 4.4
21000 -37.6 -35.7 290 52 27 6.7 3.7 | -39.2 -38.6 290 43 22 8.1 4.4
20000 -34.9 -30.8 285 46 24 9.0 4.9 | -36.8 -34.2 290 41 21 8.4 4.6
19500 -33.6 -28.5 290 44 23 8.9 4.9 | -34.9 -30.8 290 40 21 8.5 4.7
19000 -32.2 -26.0 290 43 22 8.9 4.9 | -33.6 -28.5 290 40 20 8.5 4.6
18500 -30.9 -23.6 290 41 21 8.8 4.8 | -32.3 -26.1 295 39 20 8.4 4.6
18000 -29.6 -21.3 290 40 20 7.8 4.3 | -31.1 -24.0 295 39 20 7.5 4.1
17500 -28.7 -19.7 290 40 21 4.9 2.7 | -30.3 -22.5 295 39 20 4.3 2.4
17000 -28.0 -18.4 295 41 21 5.2 2.8 | -29.6 -21.3 295 39 20 4.5 2.5
16500 -27.3 -17.1 295 40 20 3.7 2.0 | -29.0 -20.2 295 37 19 4.0 2.2
16000 -26.8 -16.2 295 36 19 3.8 2.1 | -28.4 -19.1 295 34 18 3.9 2.1
15500 -26.2 -15.2 295 33 17 4.5 2.5 | -27.6 -17.7 290 31 16 7.1 3.9
15000 -25.5 -13.9 300 31 16 4.6 2.5 | -26.5 -15.7 285 29 15 7.7 4.2
14500 -24.8 -12.6 300 29 15 4.6 2.5 | -25.3 -13.5 280 26 13 9.0 4.9
14000 -24.1 -11.4 305 27 14 4.6 2.5 | -23.9 -11.0 280 23 12 9.6 5.3
13500 -23.4 -10.1 305 25 13 5.0 2.8 | -22.4 -8.3 275 20 10 8.7 4.8
13000 -22.6 -8.7 300 21 11 5.4 3.0 | -21.3 -6.3 270 17 9 7.9 4.4
12500 -21.7 -7.1 295 17 9 8.6 4.7 | -20.1 -4.2 265 14 7 6.7 3.6
12000 -20.4 -4.7 295 14 7 6.9 3.8 | -19.3 -2.7 260 12 6 5.5 3.0
11750 -19.9 -3.8 290 13 6 7.7 4.2 | -18.9 -2.0 255 11 5 5.6 3.0
11500 -19.4 -2.9 280 11 6 5.9 3.2 | -18.5 -1.3 250 9 5 4.1 2.3
11250 -18.9 -2.0 270 10 5 6.5 3.6 | -18.2 -0.8 245 8 4 3.6 2.0
11000 -18.4 -1.1 270 9 4 8.3 4.6 | -17.9 -0.2 235 7 4 4.6 2.5
10750 -17.8 -0.0 265 7 4 7.4 4.1 | -17.6 0.3 225 7 3 4.1 2.3
10500 -17.3 0.9 255 6 3 5.4 3.0 | -17.3 0.9 215 6 3 2.4 1.3
10250 -16.9 1.6 240 5 2 5.7 3.1 | -17.2 1.0 200 6 3 1.9 1.1
10000 -16.3 2.7 220 4 2 8.9 4.9 | -17.0 1.4 185 6 3 3.3 1.8
9750 -15.6 3.9 195 3 2 9.5 5.2 | -16.7 1.9 175 7 4 4.1 2.2
9500 -15.0 5.0 180 4 2 8.8 4.8 | -16.4 2.5 170 7 4 4.5 2.5
9250 -14.3 6.3 170 4 2 8.9 4.9 | -16.1 3.0 165 8 4 4.5 2.5
9000 -13.6 7.5 160 5 3 10.9 6.0 | -15.7 3.7 160 8 4 6.2 3.4
8750 -12.7 9.1 155 6 3 10.8 5.9 | -15.1 4.8 155 8 4 8.5 4.7
8500 -12.0 10.4 150 6 3 9.7 5.3 | -14.5 5.9 155 8 4 9.0 4.9
8250 -11.3 11.7 150 6 3 9.1 5.0 | -13.8 7.2 155 8 4 8.5 4.6
8000 -10.5 13.1 150 6 3 12.4 6.8 | -13.2 8.2 155 8 4 9.9 5.4
7750 -9.3 15.3 145 6 3 21.8 12.0 | -12.3 9.9 150 8 4 14.1 7.7
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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