Soaring Guidance
Issued by NWS Pueblo, CO
Issued by NWS Pueblo, CO
782
UXUS97 KPUB 021317
SRGPUB
Soaring Forecast
National Weather Service Pueblo, Colorado
0617 MST Thursday, January 2, 2025
This forecast is for the Air Force Academy for Thursday, January 2, 2025:
If the trigger temperature of 44.4 F/6.9 C is reached...then
Thermal Soaring Index....................... Fair
Maximum rate of lift........................ 280 ft/min (1.4 m/s)
Maximum height of thermals.................. 11962 ft MSL (4349 ft AGL)
Forecast maximum temperature................... 45.0 F/7.7 C
Time of trigger temperature.................... 1145 MST
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................. 9137 ft MSL (1524 ft AGL)
Thermal soaring outlook for Friday 01/03....... Good
Wave Soaring Index............................. Not available
Remarks...
Sunrise/Sunset.................... 07:18:20 / 16:48:48 MST
Total possible sunshine........... 9 hr 30 min 27 sec (570 min 27 sec)
Altitude of sun at 12:03:34 MST... 28.18 degrees
Upper air data from numerical model forecast valid on 01/02/2025 at 0500 MST
Freezing level.................. Entire airmass below 32 F / 0 C
Convective condensation level... 16490 ft MSL (8877 ft AGL)
Lifted condensation level....... 15424 ft MSL (7811 ft AGL)
Lifted index.................... +5.3
K index......................... +7.3
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 -58.8 -73.8 300 59 30 -0.4 -0.2 M M M M M
45000 -59.3 -74.7 300 71 36 -0.4 -0.2 M M M M M
40000 -60.4 -76.7 295 74 38 -0.8 -0.4 M M M M M
38000 -60.1 -76.2 295 77 40 3.7 2.0 M M M M M
36000 -57.8 -72.0 295 83 43 3.8 2.1 M M M M M
34000 -55.2 -67.4 295 90 46 5.2 2.9 M M M M M
32000 -52.0 -61.6 295 93 48 5.4 3.0 M M M M M
30000 -48.5 -55.3 300 96 49 9.9 5.4 19.7 67.4 9.5 M M
29000 -45.6 -50.1 295 94 48 9.4 5.2 19.4 66.9 9.5 M M
28000 -42.8 -45.0 295 92 48 9.4 5.2 19.3 66.7 9.5 M M
27000 -40.0 -40.0 295 90 47 9.5 5.2 19.3 66.7 9.6 M M
26000 -37.4 -35.3 295 87 45 8.4 4.6 18.8 65.9 9.3 M M
25000 -34.9 -30.8 300 83 43 8.4 4.6 18.3 64.9 9.0 M M
24000 -32.4 -26.3 300 80 41 8.5 4.7 17.9 64.2 8.8 M M
23000 -30.1 -22.2 300 74 38 7.2 4.0 17.1 62.8 8.2 M M
22000 -27.9 -18.2 300 68 35 7.2 4.0 16.2 61.1 7.5 M M
21000 -25.3 -13.5 295 60 31 6.4 3.5 15.1 59.2 6.7 M M
20000 -23.4 -10.1 295 57 29 6.2 3.4 13.8 56.9 5.6 M M
19500 -22.5 -8.5 295 56 29 6.2 3.4 13.2 55.8 5.1 M M
19000 -21.6 -6.9 290 54 28 6.2 3.4 12.6 54.7 4.7 M M
18500 -20.7 -5.3 290 53 27 6.7 3.7 12.1 53.7 4.2 M M
18000 -19.6 -3.3 290 53 27 7.0 3.8 11.6 52.9 3.8 M M
17500 -18.6 -1.5 290 53 27 7.1 3.9 11.2 52.1 3.4 M M
17000 -17.5 0.5 290 50 26 7.4 4.1 10.7 51.3 3.0 M M
16500 -16.4 2.5 290 47 24 7.3 4.0 10.3 50.6 2.7 M M
16000 -15.3 4.5 285 43 22 8.1 4.4 10.0 50.0 2.3 M M
15500 -14.1 6.6 285 39 20 8.1 4.4 9.7 49.5 2.1 M M
15000 -12.9 8.8 285 35 18 7.9 4.3 9.5 49.0 1.9 M M
14500 -11.8 10.8 285 37 19 7.8 4.3 9.1 48.4 1.5 M M
14000 -10.6 12.9 285 39 20 7.9 4.3 8.8 47.9 1.3 M M
13500 -9.4 15.1 285 37 19 8.0 4.4 8.5 47.3 1.0 M M
13000 -8.2 17.2 290 34 18 8.7 4.8 8.2 46.8 0.7 M M
12500 -6.9 19.6 290 34 17 7.3 4.0 8.1 46.6 0.6 M M
12000 -6.0 21.2 295 32 16 6.6 3.6 7.6 45.7 0.1 M M
11750 -5.5 22.1 295 30 16 6.7 3.7 7.4 45.2 -0.2 365 1.9
11500 -5.0 23.0 300 28 15 7.1 3.9 7.1 44.8 -0.4 342 1.7
11250 -4.4 24.1 300 25 13 7.6 4.2 6.9 44.5 -0.6 318 1.6
11000 -3.8 25.2 300 21 11 7.7 4.2 6.8 44.2 -0.7 294 1.5
10750 -3.3 26.1 300 20 10 7.5 4.1 6.6 43.9 -0.9 269 1.4
10500 -2.7 27.1 300 22 11 7.4 4.1 6.4 43.6 -1.1 245 1.2
10250 -2.2 28.0 300 24 12 7.8 4.3 6.3 43.3 -1.2 221 1.1
10000 -1.6 29.1 295 26 13 6.7 3.7 6.1 43.0 -1.4 197 1.0
9750 -1.2 29.8 295 29 15 4.8 2.7 5.8 42.4 -1.8 178 0.9
9500 -0.9 30.4 295 31 16 4.9 2.7 5.4 41.7 -2.1 160 0.8
9250 -0.5 31.1 290 34 17 4.3 2.4 5.0 41.0 -2.5 142 0.7
9000 -0.4 31.3 290 38 20 -1.4 -0.7 4.4 40.0 -3.1 130 0.7
8750 -0.7 30.7 285 36 19 -4.8 -2.6 3.4 38.1 -4.2 132 0.7
8500 -1.0 30.2 285 34 18 -4.2 -2.3 2.3 36.2 -5.2 134 0.7
8250 -1.3 29.7 280 32 17 -3.1 -1.7 1.3 34.3 -6.3 136 0.7
8000 -1.5 29.3 280 30 15 -4.1 -2.2 0.3 32.6 -7.2 135 0.7
7750 -2.0 28.4 280 20 10 -9.9 -5.4 -0.9 30.3 -8.5 144 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 * * * * * *
01/02/2025 at 0800 MST | 01/02/2025 at 1100 MST
|
CAPE... 0.0 LI... +2.0 | CAPE... 0.0 LI... +3.3
CINH... 0.0 K Index... +7.4 | CINH... 0.0 K Index... -4.6
|
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 -58.8 -73.8 300 59 30 0.2 0.1 | -59.6 -75.3 300 55 28 -0.7 -0.4
45000 -58.6 -73.5 305 64 33 0.2 0.1 | -60.7 -77.3 300 67 35 -0.7 -0.4
40000 -59.4 -74.9 300 74 38 -0.6 -0.3 | -60.8 -77.4 310 97 50 -0.0 -0.0
38000 -58.8 -73.8 295 77 40 4.7 2.6 | -60.0 -76.0 310 105 54 3.2 1.7
36000 -55.6 -68.1 295 80 41 4.8 2.6 | -58.1 -72.6 310 105 54 3.2 1.7
34000 -52.7 -62.9 295 83 43 5.0 2.8 | -55.8 -68.4 310 106 55 9.0 4.9
32000 -49.6 -57.3 300 82 42 5.1 2.8 | -50.7 -59.3 315 108 55 8.5 4.7
30000 -46.6 -51.9 305 80 41 5.4 2.9 | -45.6 -50.1 315 109 56 8.3 4.6
29000 -45.0 -49.0 305 78 40 5.3 2.9 | -43.1 -45.6 320 107 55 8.4 4.6
28000 -43.4 -46.1 305 76 39 5.3 2.9 | -40.6 -41.1 320 106 54 8.4 4.6
27000 -41.8 -43.2 310 73 38 5.1 2.8 | -38.1 -36.6 320 104 54 8.3 4.5
26000 -39.7 -39.5 310 70 36 7.6 4.2 | -36.0 -32.8 320 98 50 6.5 3.6
25000 -37.4 -35.3 310 66 34 7.6 4.2 | -34.1 -29.4 320 90 47 6.5 3.6
24000 -35.2 -31.4 310 62 32 7.5 4.1 | -31.6 -24.9 320 81 42 6.4 3.5
23000 -32.5 -26.5 305 59 30 9.4 5.1 | -29.8 -21.6 315 74 38 6.2 3.4
22000 -29.7 -21.5 305 56 29 9.4 5.1 | -27.9 -18.2 315 67 34 6.2 3.4
21000 -26.3 -15.3 305 53 27 7.4 4.1 | -26.0 -14.8 315 60 31 7.5 4.1
20000 -24.2 -11.6 305 53 27 7.0 3.8 | -23.7 -10.7 310 55 28 7.6 4.2
19500 -23.2 -9.8 305 53 27 7.0 3.8 | -22.6 -8.7 310 52 27 7.6 4.2
19000 -22.2 -8.0 305 53 27 7.0 3.8 | -21.4 -6.5 310 50 26 7.5 4.1
18500 -21.1 -6.0 305 53 27 6.8 3.7 | -20.2 -4.4 310 48 25 8.8 4.8
18000 -20.1 -4.2 305 49 25 6.7 3.7 | -18.9 -2.0 310 50 26 9.1 5.0
17500 -19.1 -2.4 305 45 23 6.8 3.7 | -17.5 0.5 310 51 26 8.6 4.7
17000 -18.1 -0.6 305 39 20 7.8 4.3 | -16.4 2.5 310 52 27 6.6 3.6
16500 -16.9 1.6 305 32 17 7.7 4.2 | -15.4 4.3 310 52 27 6.8 3.7
16000 -15.7 3.7 305 28 14 8.1 4.4 | -14.5 5.9 310 52 27 5.4 3.0
15500 -14.5 5.9 305 26 13 8.1 4.4 | -13.7 7.3 310 51 27 5.5 3.0
15000 -13.3 8.1 310 25 13 8.3 4.6 | -12.9 8.8 310 50 26 5.8 3.2
14500 -12.1 10.2 310 28 15 8.4 4.6 | -12.0 10.4 310 48 24 5.9 3.2
14000 -10.8 12.6 310 31 16 8.6 4.7 | -11.1 12.0 310 45 23 6.6 3.6
13500 -9.5 14.9 310 34 18 8.7 4.8 | -10.1 13.8 305 44 23 7.2 4.0
13000 -8.2 17.2 310 37 19 9.3 5.1 | -9.0 15.8 300 44 23 8.1 4.4
12500 -6.9 19.6 310 38 20 8.0 4.4 | -7.8 18.0 300 47 24 7.7 4.2
12000 -5.8 21.6 305 43 22 7.3 4.0 | -6.7 19.9 300 45 23 7.8 4.3
11750 -5.3 22.5 305 43 22 6.9 3.8 | -6.1 21.0 300 43 22 8.5 4.7
11500 -4.7 23.5 305 42 22 7.2 3.9 | -5.5 22.1 300 41 21 8.6 4.7
11250 -4.2 24.4 305 41 21 8.0 4.4 | -4.8 23.4 295 39 20 9.1 5.0
11000 -3.6 25.5 305 40 20 7.6 4.2 | -4.2 24.4 295 38 19 8.1 4.5
10750 -3.1 26.4 305 39 20 6.8 3.7 | -3.6 25.5 295 38 20 7.3 4.0
10500 -2.6 27.3 305 38 20 6.4 3.5 | -3.1 26.4 295 39 20 6.3 3.5
10250 -2.1 28.2 300 37 19 7.7 4.2 | -2.6 27.3 295 40 21 10.4 5.7
10000 -1.5 29.3 300 38 19 7.6 4.1 | -1.7 28.9 295 40 20 8.9 4.9
9750 -1.0 30.2 300 38 20 5.9 3.3 | -1.4 29.5 295 37 19 3.7 2.1
9500 -0.6 30.9 295 40 20 6.4 3.5 | -1.0 30.2 295 35 18 4.9 2.7
9250 -0.1 31.8 295 41 21 5.3 2.9 | -0.7 30.7 290 32 16 5.5 3.0
9000 0.1 32.2 290 43 22 -2.0 -1.1 | -0.2 31.6 290 29 15 7.3 4.0
8750 -0.4 31.3 290 39 20 -6.2 -3.4 | 0.4 32.7 290 26 13 7.7 4.2
8500 -0.8 30.6 285 36 19 -5.5 -3.0 | 0.9 33.6 290 22 11 7.4 4.1
8250 -1.2 29.8 280 33 17 -4.2 -2.3 | 1.5 34.7 290 19 10 8.2 4.5
8000 -1.4 29.5 280 29 15 -3.1 -1.7 | 2.3 36.1 290 17 9 12.8 7.0
7750 -1.7 28.9 280 19 10 -6.5 -3.6 | 3.4 38.1 290 13 7 18.1 9.9
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
01/02/2025 at 1400 MST | 01/02/2025 at 1700 MST
|
CAPE... 0.0 LI... +5.6 | CAPE... 0.0 LI... +5.2
CINH... 0.0 K Index... -5.2 | CINH... 0.0 K Index... -12.8
|
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 -59.7 -75.5 310 56 29 -0.6 -0.3 | -61.0 -77.8 305 57 29 -0.8 -0.4
45000 -60.6 -77.1 300 69 35 -0.7 -0.4 | -62.2 -80.0 305 70 36 -0.6 -0.4
40000 -62.8 -81.0 305 92 47 -1.5 -0.8 | -62.4 -80.3 305 83 43 -0.1 -0.1
38000 -61.8 -79.2 305 95 49 5.3 2.9 | -61.3 -78.3 305 85 44 4.0 2.2
36000 -58.7 -73.7 300 92 47 5.3 2.9 | -58.9 -74.0 305 81 42 4.0 2.2
34000 -55.2 -67.4 300 89 46 9.0 4.9 | -55.4 -67.7 305 78 40 8.8 4.8
32000 -49.9 -57.8 305 90 47 8.7 4.8 | -50.0 -58.0 305 78 40 9.0 4.9
30000 -44.7 -48.5 305 91 47 8.8 4.8 | -44.7 -48.5 310 78 40 8.6 4.7
29000 -42.1 -43.8 305 90 46 8.8 4.8 | -42.1 -43.8 310 77 40 8.6 4.7
28000 -39.4 -38.9 310 89 46 8.8 4.8 | -39.5 -39.1 315 77 39 8.6 4.7
27000 -36.2 -33.2 310 88 46 7.6 4.2 | -37.0 -34.6 315 76 39 8.3 4.6
26000 -34.0 -29.2 310 87 45 7.5 4.1 | -34.5 -30.1 315 73 38 8.2 4.5
25000 -31.7 -25.1 315 86 44 7.5 4.1 | -32.1 -25.8 315 71 36 8.2 4.5
24000 -29.5 -21.1 320 85 44 7.9 4.3 | -29.6 -21.3 320 68 35 8.0 4.4
23000 -27.0 -16.6 320 84 43 8.3 4.5 | -27.3 -17.1 320 67 35 7.6 4.2
22000 -24.5 -12.1 325 82 42 8.3 4.5 | -25.0 -13.0 320 66 34 7.6 4.2
21000 -22.2 -8.0 325 80 41 6.3 3.4 | -22.0 -7.6 320 66 34 9.0 4.9
20000 -20.3 -4.5 325 74 38 6.3 3.4 | -19.4 -2.9 320 66 34 8.9 4.9
19500 -19.3 -2.7 320 71 37 6.3 3.4 | -18.1 -0.6 320 67 34 8.9 4.9
19000 -18.4 -1.1 320 68 35 6.3 3.4 | -16.7 1.9 320 67 34 9.0 5.0
18500 -17.5 0.5 320 64 33 6.2 3.4 | -15.5 4.1 320 66 34 7.5 4.1
18000 -16.5 2.3 320 58 30 6.2 3.4 | -14.3 6.3 320 65 33 7.7 4.2
17500 -15.6 3.9 315 51 26 6.3 3.5 | -13.2 8.2 325 64 33 6.7 3.7
17000 -14.6 5.7 315 51 26 7.1 3.9 | -12.3 9.9 325 61 31 6.2 3.4
16500 -13.5 7.7 315 54 28 7.3 4.0 | -11.4 11.5 320 58 30 6.1 3.3
16000 -12.6 9.3 315 54 28 4.5 2.5 | -10.5 13.1 320 54 28 5.9 3.2
15500 -11.9 10.6 310 51 26 4.6 2.5 | -9.6 14.7 320 50 26 6.0 3.3
15000 -11.3 11.7 310 49 25 2.8 1.5 | -8.8 16.2 320 46 24 4.5 2.5
14500 -11.0 12.2 305 48 25 2.1 1.1 | -8.1 17.4 320 43 22 4.5 2.5
14000 -10.7 12.7 305 48 25 2.3 1.3 | -7.5 18.5 315 40 21 4.6 2.5
13500 -10.4 13.3 305 46 24 2.8 1.5 | -6.8 19.8 315 40 20 4.6 2.5
13000 -10.1 13.8 300 44 22 5.3 2.9 | -6.1 21.0 315 39 20 3.2 1.8
12500 -8.9 16.0 300 41 21 6.6 3.6 | -5.8 21.6 315 34 18 2.5 1.4
12000 -8.2 17.2 300 37 19 7.2 4.0 | -5.4 22.3 310 35 18 1.9 1.1
11750 -7.5 18.5 295 36 19 10.3 5.6 | -5.3 22.5 310 34 17 1.5 0.8
11500 -6.7 19.9 300 35 18 10.0 5.5 | -5.2 22.6 310 32 17 1.4 0.8
11250 -6.0 21.2 300 34 17 9.0 4.9 | -5.2 22.6 305 32 16 0.1 0.1
11000 -5.3 22.5 300 33 17 9.1 5.0 | -5.2 22.6 305 31 16 3.3 1.8
10750 -4.6 23.7 300 31 16 9.7 5.3 | -4.8 23.4 305 29 15 6.3 3.5
10500 -3.9 25.0 300 30 15 9.1 5.0 | -4.4 24.1 305 27 14 5.3 2.9
10250 -3.2 26.2 300 28 14 11.2 6.1 | -4.0 24.8 300 25 13 6.2 3.4
10000 -2.3 27.9 300 27 14 11.0 6.0 | -3.5 25.7 300 24 12 8.1 4.5
9750 -1.6 29.1 300 26 13 9.0 4.9 | -2.8 27.0 300 21 11 8.8 4.8
9500 -0.9 30.4 300 24 12 9.2 5.0 | -2.2 28.0 305 19 10 9.0 4.9
9250 -0.2 31.6 305 23 12 10.3 5.7 | -1.6 29.1 305 17 9 7.7 4.2
9000 0.6 33.1 305 21 11 10.7 5.9 | -1.0 30.2 305 15 8 7.7 4.2
8750 1.3 34.3 305 20 11 9.7 5.3 | -0.4 31.3 310 13 6 8.8 4.8
8500 2.8 37.0 310 18 9 10.9 6.0 | 0.2 32.4 315 10 5 8.8 4.9
8250 3.7 38.7 310 18 9 13.6 7.5 | 0.9 33.6 320 8 4 7.5 4.1
8000 4.8 40.6 310 14 7 14.1 7.7 | 0.6 33.1 340 5 3 -11.6 -6.4
7750 5.8 42.4 315 11 6 14.4 7.9 | 0.1 32.2 360 3 2 4.9 2.7
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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