Soaring Guidance
Issued by NWS Pueblo, CO
Issued by NWS Pueblo, CO
064
UXUS97 KPUB 061229
SRGPUB
Soaring Forecast
National Weather Service Pueblo, Colorado
0627 MDT Monday, May 6, 2024
This forecast is for the Air Force Academy for Monday, May 6, 2024:
If the trigger temperature of 44.9 F/7.2 C is reached...then
Thermal Soaring Index....................... Poor
Maximum rate of lift........................ 153 ft/min (0.8 m/s)
Maximum height of thermals.................. 13244 ft MSL (5659 ft AGL)
Forecast maximum temperature................... 57.0 F/14.3 C
Time of trigger temperature.................... 0900 MDT
Time of overdevelopment........................ None
Middle/high clouds during soaring window....... Broken/overcast thin middle
Surface winds during soaring window............ More than 30 mph
Height of the -3 thermal index................. 12368 ft MSL (4783 ft AGL)
Thermal soaring outlook for Tuesday 05/07...... Good
Wave Soaring Index............................. Not available
Remarks...
Sunrise/Sunset.................... 05:54:32 / 19:57:11 MDT
Total possible sunshine........... 14 hr 2 min 39 sec (842 min 39 sec)
Altitude of sun at 12:55:51 MDT... 67.84 degrees
Upper air data from numerical model forecast valid on 05/06/2024 at 0600 MDT
Freezing level.................. 8880 ft MSL (1295 ft AGL)
Convective condensation level... 20009 ft MSL (12424 ft AGL)
Lifted condensation level....... 18126 ft MSL (10540 ft AGL)
Lifted index.................... +4.1
K index......................... -34.1
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 -53.7 -64.7 235 24 13 1.8 1.0 M M M M M
45000 -51.0 -59.8 220 38 20 0.5 0.3 M M M M M
40000 -51.9 -61.4 210 61 32 -0.5 -0.3 M M M M M
38000 -51.2 -60.2 210 68 35 2.5 1.4 M M M M M
36000 -49.7 -57.5 210 73 38 2.5 1.4 M M M M M
34000 -48.0 -54.4 205 77 40 5.5 3.0 M M M M M
32000 -44.9 -48.8 205 78 40 5.3 2.9 M M M M M
30000 -41.6 -42.9 205 79 41 7.0 3.9 27.6 81.6 10.5 M M
29000 -39.5 -39.1 205 79 41 7.0 3.9 26.4 79.4 9.7 M M
28000 -37.4 -35.3 205 79 41 7.0 3.9 25.3 77.6 9.0 M M
27000 -35.2 -31.4 205 79 41 7.0 3.8 24.4 75.9 8.4 M M
26000 -33.0 -27.4 205 79 41 7.6 4.2 23.5 74.3 7.8 M M
25000 -30.7 -23.3 210 80 41 7.6 4.2 22.7 72.8 7.2 M M
24000 -28.4 -19.1 210 80 41 7.7 4.2 22.0 71.5 6.7 M M
23000 -26.1 -15.0 215 80 41 8.0 4.4 21.3 70.3 6.2 M M
22000 -23.1 -9.6 215 77 40 8.0 4.4 20.4 68.8 5.6 M M
21000 -20.7 -5.3 215 76 39 8.1 4.5 19.9 67.8 5.2 M M
20000 -18.1 -0.6 220 73 38 8.6 4.7 19.4 66.9 4.8 M M
19500 -16.8 1.8 220 72 37 8.6 4.7 19.2 66.6 4.7 M M
19000 -15.5 4.1 220 71 37 8.6 4.7 19.0 66.3 4.5 M M
18500 -14.2 6.4 220 70 36 8.8 4.8 18.9 66.0 4.4 M M
18000 -13.1 8.4 220 71 37 5.7 3.1 18.5 65.3 4.1 M M
17500 -12.2 10.0 225 74 38 6.0 3.3 17.8 64.1 3.5 M M
17000 -11.3 11.7 225 77 40 5.8 3.2 17.2 63.0 3.0 M M
16500 -10.5 13.1 225 75 39 5.7 3.1 16.5 61.7 2.4 M M
16000 -9.7 14.5 225 73 38 6.1 3.3 15.9 60.5 1.8 M M
15500 -8.4 16.9 225 68 35 9.7 5.3 15.6 60.1 1.5 M M
15000 -7.0 19.4 220 62 32 9.6 5.2 15.6 60.0 1.5 M M
14500 -5.7 21.7 215 57 30 8.1 4.4 15.4 59.7 1.4 M M
14000 -4.5 23.9 215 54 28 8.3 4.5 15.1 59.3 1.1 M M
13500 -3.4 25.9 220 52 27 3.0 1.6 14.7 58.4 0.7 M M
13000 -3.3 26.1 225 52 27 1.6 0.9 13.3 55.9 -0.6 345 1.8
12500 -3.5 25.7 230 54 28 -4.7 -2.6 11.5 52.6 -2.3 337 1.7
12000 -4.2 24.4 240 53 27 -3.6 -2.0 9.2 48.6 -4.5 343 1.7
11750 -4.6 23.7 245 54 28 -6.2 -3.4 8.1 46.7 -5.6 345 1.8
11500 -4.9 23.2 250 54 28 4.0 2.2 7.1 44.7 -6.7 348 1.8
11250 -4.2 24.4 250 52 27 8.4 4.6 7.1 44.8 -6.7 319 1.6
11000 -4.0 24.8 250 52 27 1.6 0.9 6.6 43.8 -7.3 305 1.6
10750 -3.8 25.2 255 51 26 3.2 1.8 6.0 42.9 -7.8 292 1.5
10500 -3.6 25.5 255 51 26 4.1 2.3 5.5 42.0 -8.4 279 1.4
10250 -3.2 26.2 255 50 26 5.9 3.2 5.2 41.4 -8.8 260 1.3
10000 -2.8 27.0 260 48 25 5.8 3.2 4.9 40.8 -9.1 241 1.2
9750 -2.4 27.7 260 46 24 5.7 3.1 4.6 40.2 -9.5 221 1.1
9500 -1.9 28.6 260 45 23 8.2 4.5 4.3 39.8 -9.8 200 1.0
9250 -1.2 29.8 260 44 22 10.0 5.5 4.3 39.8 -9.8 171 0.9
9000 -0.5 31.1 260 42 22 9.3 5.1 4.3 39.7 -9.9 143 0.7
8750 0.2 32.4 260 40 21 9.3 5.1 4.3 39.7 -9.9 115 0.6
8500 0.9 33.6 260 38 20 9.1 5.0 4.2 39.6 -10.0 87 0.4
8250 1.5 34.7 260 36 19 8.8 4.8 4.2 39.5 -10.1 59 0.3
8000 2.2 36.0 260 34 17 10.1 5.5 4.1 39.4 -10.2 31 0.2
7750 3.0 37.4 260 30 15 9.8 5.4 4.2 39.5 -10.2 1 0.0
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 * * * * * *
05/06/2024 at 0900 MDT | 05/06/2024 at 1200 MDT
|
CAPE... 0.0 LI... +8.3 | CAPE... +6.0 LI... +1.5
CINH... 0.0 K Index... -30.4 | CINH... 0.0 K Index... -6.6
|
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 -51.7 -61.1 245 22 11 2.9 1.6 | -52.2 -62.0 210 14 7 3.0 1.6
45000 -47.3 -53.1 235 35 18 1.9 1.0 | -47.7 -53.9 220 12 6 2.5 1.4
40000 -47.9 -54.2 215 53 27 -0.4 -0.2 | -44.6 -48.3 230 54 28 2.0 1.1
38000 -48.0 -54.4 215 59 30 0.5 0.3 | -44.2 -47.6 230 61 32 -1.3 -0.7
36000 -47.7 -53.9 215 63 33 0.5 0.3 | -44.9 -48.8 225 58 30 -1.3 -0.7
34000 -47.4 -53.3 210 67 35 1.5 0.8 | -45.7 -50.3 225 54 28 -0.4 -0.2
32000 -45.2 -49.4 210 72 37 3.9 2.1 | -43.9 -47.0 230 59 30 3.2 1.8
30000 -42.5 -44.5 205 78 40 6.1 3.4 | -42.0 -43.6 235 64 33 3.3 1.8
29000 -40.5 -40.9 205 78 40 6.7 3.7 | -40.6 -41.1 235 65 34 5.1 2.8
28000 -38.5 -37.3 200 78 40 6.7 3.7 | -39.0 -38.2 240 67 34 5.1 2.8
27000 -36.5 -33.7 200 79 40 6.6 3.6 | -37.5 -35.5 240 68 35 5.1 2.8
26000 -34.3 -29.7 200 78 40 7.8 4.3 | -35.9 -32.6 240 67 35 5.1 2.8
25000 -31.9 -25.4 200 78 40 7.9 4.3 | -34.4 -29.9 245 64 33 5.1 2.8
24000 -29.6 -21.3 200 77 40 7.8 4.3 | -32.9 -27.2 245 60 31 5.1 2.8
23000 -27.3 -17.1 200 77 39 7.0 3.8 | -31.4 -24.5 245 56 29 4.3 2.4
22000 -25.2 -13.4 205 76 39 7.0 3.9 | -29.8 -21.6 240 45 23 4.3 2.3
21000 -23.1 -9.6 205 76 39 7.0 3.8 | -28.5 -19.3 240 37 19 4.2 2.3
20000 -20.8 -5.4 205 73 38 8.0 4.4 | -26.8 -16.2 240 31 16 6.2 3.4
19500 -19.6 -3.3 200 71 36 8.1 4.4 | -25.9 -14.6 240 29 15 6.2 3.4
19000 -18.4 -1.1 200 68 35 8.0 4.4 | -25.0 -13.0 245 27 14 6.2 3.4
18500 -17.2 1.0 195 65 34 7.9 4.3 | -24.0 -11.2 245 25 13 6.2 3.4
18000 -16.0 3.2 195 63 33 6.0 3.3 | -23.1 -9.6 250 24 12 7.2 4.0
17500 -15.5 4.1 200 63 32 3.2 1.8 | -21.9 -7.4 255 26 13 7.4 4.1
17000 -14.8 5.4 210 63 32 2.7 1.5 | -20.8 -5.4 260 28 14 7.1 3.9
16500 -14.5 5.9 215 60 31 2.1 1.2 | -19.8 -3.6 265 30 16 6.3 3.5
16000 -14.2 6.4 220 58 30 2.1 1.2 | -18.9 -2.0 270 33 17 6.3 3.5
15500 -13.9 7.0 225 55 28 1.4 0.8 | -18.0 -0.4 275 35 18 5.7 3.1
15000 -13.7 7.3 235 50 26 1.1 0.6 | -17.2 1.0 275 37 19 5.6 3.1
14500 -13.2 8.2 240 47 24 6.8 3.7 | -16.2 2.8 275 38 20 8.7 4.8
14000 -12.2 10.0 245 43 22 7.0 3.9 | -14.9 5.2 275 37 19 8.8 4.8
13500 -11.2 11.8 250 40 20 5.2 2.8 | -13.5 7.7 275 35 18 11.2 6.1
13000 -10.5 13.1 255 41 21 3.8 2.1 | -11.7 10.9 275 35 18 13.0 7.1
12500 -9.4 15.1 260 44 23 9.7 5.3 | -10.6 12.9 275 35 18 5.8 3.2
12000 -8.3 17.1 265 45 23 8.1 4.4 | -9.1 15.6 275 35 18 9.5 5.2
11750 -7.7 18.1 265 46 24 6.5 3.6 | -8.3 17.1 275 34 18 10.6 5.8
11500 -7.3 18.9 270 46 23 4.9 2.7 | -7.5 18.5 275 34 18 10.9 6.0
11250 -6.9 19.6 270 44 23 7.1 3.9 | -6.7 19.9 275 34 18 9.7 5.3
11000 -6.3 20.7 270 43 22 8.7 4.8 | -6.0 21.2 275 34 17 9.2 5.0
10750 -5.7 21.7 270 42 21 8.5 4.7 | -5.3 22.5 275 34 17 9.3 5.1
10500 -5.2 22.6 270 40 21 6.8 3.7 | -4.7 23.5 275 34 17 8.2 4.5
10250 -4.7 23.5 270 40 20 8.8 4.8 | -4.0 24.8 275 33 17 9.9 5.4
10000 -3.8 25.2 270 38 20 11.9 6.5 | -3.2 26.2 275 33 17 12.0 6.6
9750 -3.0 26.6 270 37 19 10.8 5.9 | -2.3 27.9 275 33 17 10.9 6.0
9500 -2.3 27.9 270 37 19 8.9 4.9 | -1.6 29.1 275 33 17 9.1 5.0
9250 -1.6 29.1 270 36 18 9.0 4.9 | -0.9 30.4 275 32 17 9.4 5.1
9000 -0.8 30.6 270 35 18 12.0 6.6 | -0.1 31.8 275 32 16 11.8 6.5
8750 0.1 32.2 270 34 17 11.7 6.4 | 0.8 33.4 275 31 16 11.7 6.4
8500 0.9 33.6 270 33 17 9.8 5.4 | 1.6 34.9 275 31 16 10.8 5.9
8250 1.6 34.9 270 32 16 9.7 5.3 | 2.4 36.3 275 30 16 10.7 5.9
8000 2.3 36.1 270 30 16 10.6 5.8 | 3.3 37.9 275 29 15 11.7 6.4
7750 3.3 37.9 270 27 14 17.0 9.4 | 4.5 40.1 275 27 14 23.4 12.8
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
05/06/2024 at 1500 MDT | 05/06/2024 at 1800 MDT
|
CAPE... +106.0 LI... -1.5 | CAPE... +60.4 LI... -0.8
CINH... 0.0 K Index... +9.9 | CINH... 0.0 K Index... +12.2
|
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 -51.3 -60.3 235 22 11 2.2 1.2 | -50.6 -59.1 245 25 13 1.8 1.0
45000 -48.0 -54.4 255 23 12 2.1 1.2 | -47.9 -54.2 260 26 13 1.6 0.9
40000 -44.9 -48.8 245 49 25 2.0 1.1 | -45.6 -50.1 270 42 21 1.5 0.8
38000 -44.0 -47.2 245 54 28 0.3 0.2 | -45.0 -49.0 270 44 23 0.4 0.2
36000 -43.8 -46.8 250 49 25 0.3 0.2 | -44.7 -48.5 270 43 22 0.4 0.2
34000 -43.5 -46.3 250 43 22 0.3 0.2 | -44.5 -48.1 270 41 21 0.4 0.2
32000 -43.5 -46.3 255 47 24 0.1 0.1 | -44.4 -47.9 275 36 19 0.1 0.0
30000 -43.4 -46.1 255 52 27 0.0 0.0 | -44.4 -47.9 285 31 16 0.3 0.1
29000 -42.4 -44.3 255 54 28 4.3 2.4 | -43.6 -46.5 295 27 14 3.0 1.6
28000 -41.1 -42.0 255 55 29 4.3 2.4 | -42.7 -44.9 305 23 12 3.0 1.6
27000 -39.8 -39.6 255 57 29 4.3 2.4 | -41.8 -43.2 325 21 11 3.1 1.7
26000 -38.3 -36.9 255 57 30 6.7 3.7 | -40.3 -40.5 330 20 10 9.1 5.0
25000 -36.4 -33.5 255 57 29 6.5 3.6 | -37.6 -35.7 310 17 9 8.8 4.8
24000 -34.4 -29.9 250 56 29 6.5 3.6 | -35.0 -31.0 290 17 9 8.8 4.8
23000 -32.1 -25.8 250 54 28 6.0 3.3 | -32.1 -25.8 275 19 10 6.7 3.7
22000 -30.2 -22.4 250 49 25 6.0 3.3 | -30.1 -22.2 280 22 12 6.7 3.7
21000 -28.4 -19.1 250 44 23 6.2 3.4 | -28.1 -18.6 280 25 13 6.8 3.7
20000 -27.2 -17.0 255 39 20 3.5 1.9 | -26.3 -15.3 290 25 13 5.9 3.2
19500 -26.6 -15.9 255 35 18 3.6 2.0 | -25.4 -13.7 295 25 13 5.9 3.2
19000 -26.1 -15.0 260 32 17 3.6 2.0 | -24.5 -12.1 300 25 13 5.9 3.2
18500 -25.6 -14.1 265 29 15 3.3 1.8 | -23.6 -10.5 305 26 13 5.6 3.1
18000 -24.8 -12.6 270 28 14 8.2 4.5 | -22.6 -8.7 305 27 14 8.4 4.6
17500 -23.6 -10.5 275 29 15 8.7 4.8 | -21.4 -6.5 305 29 15 8.3 4.5
17000 -22.3 -8.1 280 31 16 8.9 4.9 | -20.2 -4.4 300 31 16 7.9 4.3
16500 -20.9 -5.6 280 32 16 9.2 5.1 | -19.1 -2.4 300 32 16 7.6 4.2
16000 -19.6 -3.3 280 33 17 9.3 5.1 | -18.0 -0.4 295 33 17 7.9 4.3
15500 -18.1 -0.6 280 33 17 10.0 5.5 | -16.7 1.9 290 32 17 9.3 5.1
15000 -16.6 2.1 280 33 17 10.0 5.5 | -15.3 4.5 285 32 16 9.2 5.0
14500 -15.2 4.6 280 32 17 9.6 5.3 | -13.9 7.0 285 31 16 9.8 5.4
14000 -13.7 7.3 280 32 17 9.5 5.2 | -12.4 9.7 285 31 16 9.6 5.3
13500 -12.2 10.0 280 32 17 11.8 6.5 | -10.9 12.4 285 31 16 11.8 6.5
13000 -10.4 13.3 280 32 16 13.5 7.4 | -9.1 15.6 285 31 16 13.2 7.2
12500 -9.2 15.4 280 32 16 5.3 2.9 | -8.0 17.6 285 31 16 5.3 2.9
12000 -7.7 18.1 280 32 16 9.3 5.1 | -6.5 20.3 285 30 16 9.3 5.1
11750 -7.0 19.4 280 32 16 11.5 6.3 | -5.8 21.6 285 30 16 11.2 6.1
11500 -6.1 21.0 280 31 16 11.4 6.3 | -4.9 23.2 285 30 15 10.7 5.9
11250 -5.3 22.5 280 31 16 9.0 5.0 | -4.2 24.4 285 30 15 8.9 4.9
11000 -4.7 23.5 280 31 16 9.0 4.9 | -3.5 25.7 285 30 15 9.1 5.0
10750 -4.0 24.8 280 31 16 9.1 5.0 | -2.8 27.0 285 29 15 9.3 5.1
10500 -3.3 26.1 280 31 16 9.5 5.2 | -2.1 28.2 285 29 15 10.2 5.6
10250 -2.5 27.5 280 31 16 10.1 5.6 | -1.3 29.7 285 29 15 10.2 5.6
10000 -1.8 28.8 280 30 16 10.4 5.7 | -0.6 30.9 285 29 15 10.0 5.5
9750 -1.0 30.2 280 30 16 10.2 5.6 | 0.2 32.4 285 29 15 9.9 5.4
9500 -0.2 31.6 280 30 15 9.9 5.4 | 0.9 33.6 285 28 15 9.3 5.1
9250 0.5 32.9 280 30 15 10.0 5.5 | 1.6 34.9 285 28 14 9.8 5.4
9000 1.3 34.3 280 30 15 10.3 5.6 | 2.4 36.3 285 28 14 11.1 6.1
8750 2.0 35.6 280 29 15 10.8 5.9 | 3.2 37.8 285 27 14 10.8 5.9
8500 2.9 37.2 280 29 15 11.4 6.3 | 4.0 39.2 285 27 14 10.3 5.6
8250 3.7 38.7 280 28 15 11.3 6.2 | 4.8 40.6 285 26 13 10.2 5.6
8000 4.5 40.1 280 28 14 10.5 5.7 | 5.5 41.9 285 25 13 10.0 5.5
7750 5.5 41.9 285 25 13 19.9 10.9 | 6.4 43.5 285 22 11 15.0 8.2
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
________________________________________________________________________________
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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