Soaring Guidance
Issued by NWS Pueblo, CO
Issued by NWS Pueblo, CO
656
UXUS97 KPUB 021226
SRGPUB
Soaring Forecast
National Weather Service Pueblo, Colorado
0626 MDT Thursday, May 2, 2024
This forecast is for the Air Force Academy for Thursday, May 2, 2024:
If the trigger temperature of 46.5 F/8.1 C is reached...then
Thermal Soaring Index....................... Excellent
Maximum rate of lift........................ 1031 ft/min (5.2 m/s)
Maximum height of thermals.................. 19215 ft MSL (11579 ft AGL)
Forecast maximum temperature................... 61.0 F/16.6 C
Time of trigger temperature.................... 0930 MDT
Time of overdevelopment........................ None
Middle/high clouds during soaring window....... None
Surface winds during soaring window............ 20 mph or less
Height of the -3 thermal index................. 16705 ft MSL (9069 ft AGL)
Thermal soaring outlook for Friday 05/03....... Excellent
Wave Soaring Index............................. Not available
Remarks...
Sunrise/Sunset.................... 05:59:02 / 19:53:21 MDT
Total possible sunshine........... 13 hr 54 min 19 sec (834 min 19 sec)
Altitude of sun at 12:56:11 MDT... 66.70 degrees
Upper air data from numerical model forecast valid on 05/02/2024 at 0600 MDT
Freezing level.................. 7731 ft MSL (95 ft AGL)
Additional freezing level....... 9956 ft MSL (2320 ft AGL)
Convective condensation level... 17531 ft MSL (9895 ft AGL)
Lifted condensation level....... 18493 ft MSL (10858 ft AGL)
Lifted index.................... -0.4
K index......................... -20.8
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 -54.6 -66.3 235 43 22 1.7 0.9 M M M M M
45000 -52.3 -62.1 235 54 28 -0.9 -0.5 M M M M M
40000 -55.0 -67.0 235 64 33 -1.8 -1.0 M M M M M
38000 -54.5 -66.1 235 69 36 4.0 2.2 M M M M M
36000 -51.9 -61.4 235 76 39 3.9 2.2 M M M M M
34000 -49.5 -57.1 235 81 42 4.5 2.5 M M M M M
32000 -46.8 -52.2 235 80 41 4.5 2.5 M M M M M
30000 -43.9 -47.0 235 79 40 7.1 3.9 25.0 77.0 6.8 M M
29000 -41.8 -43.2 235 76 39 6.9 3.8 23.8 74.8 6.0 M M
28000 -39.7 -39.5 235 74 38 6.9 3.8 22.7 72.9 5.2 M M
27000 -37.6 -35.7 235 72 37 6.9 3.8 21.8 71.2 4.5 M M
26000 -35.5 -31.9 240 69 35 7.0 3.8 20.7 69.2 3.7 M M
25000 -33.5 -28.3 240 66 34 7.0 3.8 19.6 67.3 2.9 M M
24000 -31.4 -24.5 245 64 33 6.7 3.7 18.7 65.7 2.1 M M
23000 -28.8 -19.8 245 63 32 9.0 4.9 18.2 64.7 1.7 M M
22000 -25.5 -13.9 245 62 32 9.0 4.9 17.8 64.1 1.4 M M
21000 -22.9 -9.2 250 61 31 7.6 4.2 17.5 63.6 1.2 M M
20000 -20.7 -5.3 250 58 30 7.5 4.1 16.7 62.0 0.5 M M
19500 -19.5 -3.1 250 56 29 7.4 4.1 16.3 61.3 0.1 M M
19000 -18.4 -1.1 250 55 28 7.4 4.1 15.9 60.7 -0.2 1004 5.1
18500 -17.3 0.9 250 53 27 6.2 3.4 15.6 60.0 -0.5 957 4.9
18000 -16.5 2.3 250 52 27 5.5 3.0 14.8 58.7 -1.2 917 4.7
17500 -15.7 3.7 250 50 26 5.4 3.0 14.1 57.4 -1.8 878 4.5
17000 -15.0 5.0 255 48 25 4.5 2.5 13.3 55.9 -2.6 842 4.3
16500 -14.3 6.3 255 47 24 4.6 2.5 12.4 54.4 -3.4 807 4.1
16000 -13.6 7.5 260 45 23 5.2 2.8 11.6 53.0 -4.1 771 3.9
15500 -12.8 9.0 260 42 22 5.3 2.9 10.9 51.6 -4.9 733 3.7
15000 -12.1 10.2 260 40 21 6.5 3.6 10.2 50.4 -5.6 695 3.5
14500 -10.9 12.4 265 38 20 7.4 4.0 9.8 49.7 -6.0 647 3.3
14000 -9.8 14.4 265 37 19 7.5 4.1 9.5 49.0 -6.3 598 3.0
13500 -8.7 16.3 265 35 18 7.8 4.3 9.1 48.4 -6.7 549 2.8
13000 -7.5 18.5 270 33 17 9.1 5.0 8.8 47.9 -7.0 500 2.5
12500 -6.0 21.2 270 32 16 8.2 4.5 8.8 47.9 -7.0 441 2.2
12000 -4.9 23.2 270 30 15 7.6 4.2 8.5 47.2 -7.5 394 2.0
11750 -4.4 24.1 270 29 15 8.5 4.7 8.3 47.0 -7.6 369 1.9
11500 -3.7 25.3 270 28 15 8.9 4.9 8.2 46.8 -7.7 342 1.7
11250 -3.1 26.4 270 27 14 8.7 4.8 8.2 46.7 -7.8 315 1.6
11000 -2.4 27.7 270 27 14 8.5 4.7 8.1 46.5 -7.9 289 1.5
10750 -1.8 28.8 270 25 13 7.7 4.2 7.9 46.3 -8.1 263 1.3
10500 -1.3 29.7 275 24 12 7.1 3.9 7.8 46.0 -8.3 240 1.2
10250 -0.8 30.6 275 23 12 8.1 4.4 7.6 45.7 -8.5 217 1.1
10000 -0.2 31.6 275 22 12 7.1 3.9 7.5 45.4 -8.7 192 1.0
9750 0.2 32.4 275 21 11 3.7 2.0 7.1 44.8 -9.1 174 0.9
9500 0.3 32.5 275 19 10 2.5 1.4 6.6 43.8 -9.7 162 0.8
9250 0.5 32.9 275 17 9 3.8 2.1 6.1 42.9 -10.3 149 0.8
9000 0.7 33.3 275 14 7 4.5 2.5 5.7 42.2 -10.8 134 0.7
8750 1.0 33.8 280 12 6 3.7 2.1 5.2 41.4 -11.3 119 0.6
8500 1.2 34.2 280 10 5 3.9 2.2 4.8 40.6 -11.9 105 0.5
8250 1.4 34.5 285 8 4 2.9 1.6 4.3 39.8 -12.4 91 0.5
8000 0.5 32.9 295 4 2 -15.7 -8.6 2.0 35.6 -14.8 104 0.5
7750 -0.3 31.5 315 2 1 1.4 0.8 0.4 32.8 -16.5 122 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 * * * * * *
05/02/2024 at 0900 MDT | 05/02/2024 at 1200 MDT
|
CAPE... +1.1 LI... +3.7 | CAPE... +56.9 LI... +2.7
CINH... 0.0 K Index... -17.9 | CINH... 0.0 K Index... +1.2
|
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 -54.1 -65.4 235 42 21 1.1 0.6 | -54.1 -65.4 240 48 24 1.5 0.8
45000 -52.5 -62.5 235 55 29 0.4 0.2 | -51.9 -61.4 240 60 31 -0.4 -0.2
40000 -52.4 -62.3 240 61 31 0.0 0.0 | -53.7 -64.7 240 64 33 -1.2 -0.7
38000 -52.4 -62.3 240 64 33 -0.1 -0.1 | -53.8 -64.8 245 65 34 1.0 0.6
36000 -52.5 -62.5 245 67 34 -0.1 -0.1 | -53.1 -63.6 245 66 34 1.0 0.6
34000 -52.0 -61.6 245 69 35 5.8 3.2 | -51.9 -61.4 250 67 34 6.6 3.6
32000 -48.8 -55.8 245 66 34 5.4 3.0 | -48.1 -54.6 250 67 35 6.3 3.5
30000 -45.2 -49.4 250 63 32 8.7 4.8 | -44.1 -47.4 255 68 35 7.8 4.3
29000 -42.6 -44.7 250 63 32 8.6 4.7 | -41.8 -43.2 255 67 34 7.8 4.3
28000 -40.0 -40.0 250 63 32 8.6 4.7 | -39.4 -38.9 255 66 34 7.8 4.3
27000 -37.5 -35.5 255 63 32 8.4 4.6 | -37.1 -34.8 255 65 34 7.8 4.3
26000 -35.2 -31.4 255 62 32 7.5 4.1 | -34.8 -30.6 255 65 33 7.6 4.2
25000 -32.9 -27.2 260 61 32 7.5 4.1 | -32.6 -26.7 255 65 33 7.6 4.2
24000 -30.7 -23.3 260 61 31 7.4 4.1 | -30.3 -22.5 255 65 33 7.6 4.2
23000 -28.2 -18.8 260 60 31 8.4 4.6 | -27.9 -18.2 255 65 33 8.1 4.4
22000 -25.1 -13.2 260 59 30 8.4 4.6 | -25.5 -13.9 255 64 33 8.1 4.4
21000 -22.6 -8.7 260 58 30 8.0 4.4 | -22.4 -8.3 250 63 32 8.7 4.8
20000 -20.2 -4.4 260 57 29 8.0 4.4 | -19.8 -3.6 250 58 30 8.8 4.8
19500 -19.0 -2.2 260 56 29 8.0 4.4 | -18.5 -1.3 245 55 28 8.8 4.8
19000 -17.8 -0.0 260 56 29 8.0 4.4 | -17.2 1.0 245 53 27 8.9 4.9
18500 -16.7 1.9 260 55 28 6.6 3.6 | -16.0 3.2 245 51 26 5.4 3.0
18000 -15.8 3.6 265 54 28 6.0 3.3 | -15.4 4.3 250 52 27 4.2 2.3
17500 -14.9 5.2 265 53 27 5.8 3.2 | -14.8 5.4 260 55 28 3.9 2.1
17000 -14.1 6.6 265 51 27 4.8 2.7 | -14.3 6.3 260 55 28 2.7 1.5
16500 -13.4 7.9 265 50 26 4.9 2.7 | -13.9 7.0 265 53 27 2.7 1.5
16000 -12.7 9.1 270 49 25 4.5 2.5 | -13.5 7.7 265 50 26 4.1 2.3
15500 -12.0 10.4 270 47 24 4.5 2.5 | -12.9 8.8 265 43 22 4.3 2.4
15000 -11.3 11.7 270 45 23 5.3 2.9 | -12.3 9.9 265 37 19 7.0 3.9
14500 -10.5 13.1 270 43 22 5.8 3.2 | -11.0 12.2 265 31 16 8.5 4.6
14000 -9.6 14.7 270 40 21 6.0 3.3 | -9.7 14.5 265 26 13 8.5 4.6
13500 -8.7 16.3 270 37 19 6.4 3.5 | -8.5 16.7 265 23 12 8.4 4.6
13000 -7.7 18.1 270 33 17 6.9 3.8 | -7.3 18.9 260 20 10 9.6 5.3
12500 -6.7 19.9 270 30 15 5.9 3.2 | -5.9 21.4 260 18 9 8.3 4.5
12000 -5.9 21.4 265 24 12 5.9 3.2 | -4.7 23.5 255 14 7 8.1 4.5
11750 -5.4 22.3 260 22 11 7.1 3.9 | -4.1 24.6 250 13 7 7.4 4.1
11500 -4.9 23.2 260 21 11 7.5 4.1 | -3.6 25.5 245 12 6 8.6 4.7
11250 -4.4 24.1 260 20 10 7.4 4.1 | -2.9 26.8 240 11 5 10.4 5.7
11000 -3.9 25.0 260 19 10 7.3 4.0 | -2.1 28.2 230 10 5 9.5 5.2
10750 -3.4 25.9 260 18 9 6.8 3.7 | -1.5 29.3 225 9 5 8.2 4.5
10500 -2.9 26.8 255 17 9 6.3 3.5 | -0.9 30.4 215 9 4 7.6 4.2
10250 -2.4 27.7 255 16 8 8.1 4.4 | -0.3 31.5 205 9 4 10.6 5.8
10000 -1.8 28.8 250 15 8 8.5 4.7 | 0.6 33.1 205 8 4 11.6 6.4
9750 -1.3 29.7 245 13 7 6.7 3.7 | 1.4 34.5 200 8 4 9.6 5.2
9500 -0.9 30.4 240 11 5 6.4 3.5 | 2.1 35.8 195 8 4 9.1 5.0
9250 -0.5 31.1 235 8 4 7.6 4.2 | 2.8 37.0 195 8 4 10.5 5.7
9000 0.1 32.2 220 7 4 9.2 5.1 | 3.6 38.5 190 8 4 11.0 6.0
8750 0.8 33.4 210 6 3 9.5 5.2 | 4.4 39.9 190 8 4 9.9 5.4
8500 1.5 34.7 200 5 3 8.9 4.9 | 5.1 41.2 185 8 4 9.6 5.3
8250 2.2 36.0 185 5 2 10.6 5.8 | 5.9 42.6 185 8 4 11.0 6.0
8000 3.2 37.8 175 4 2 15.8 8.7 | 6.9 44.4 185 8 4 19.2 10.5
7750 4.5 40.1 170 4 2 19.4 10.6 | 8.7 47.7 180 8 4 28.6 15.7
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
05/02/2024 at 1500 MDT | 05/02/2024 at 1800 MDT
|
CAPE... +193.1 LI... -1.7 | CAPE... +160.4 LI... -1.3
CINH... -1.2 K Index... +18.8 | CINH... -13.4 K Index... +17.7
|
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 -54.8 -66.6 240 38 19 2.0 1.1 | -54.5 -66.1 240 37 19 2.5 1.4
45000 -51.9 -61.4 245 55 28 -0.9 -0.5 | -50.9 -59.6 245 45 23 -2.1 -1.2
40000 -54.8 -66.6 245 63 33 -1.9 -1.1 | -56.7 -70.1 260 59 30 -3.8 -2.1
38000 -54.9 -66.8 255 66 34 1.9 1.0 | -57.0 -70.6 260 65 33 3.6 2.0
36000 -53.7 -64.7 265 70 36 1.9 1.0 | -54.6 -66.3 265 71 36 3.6 2.0
34000 -51.9 -61.4 275 75 39 7.0 3.9 | -52.0 -61.6 270 75 38 6.8 3.7
32000 -47.8 -54.0 265 74 38 6.9 3.8 | -48.0 -54.4 270 73 38 6.8 3.7
30000 -43.6 -46.5 265 74 38 7.4 4.0 | -43.9 -47.0 270 71 37 7.1 3.9
29000 -41.4 -42.5 265 74 38 7.4 4.0 | -41.7 -43.1 270 69 36 7.1 3.9
28000 -39.2 -38.6 265 73 38 7.4 4.0 | -39.6 -39.3 270 68 35 7.1 3.9
27000 -37.0 -34.6 265 73 37 7.2 3.9 | -37.5 -35.5 265 66 34 7.0 3.8
26000 -35.0 -31.0 265 71 37 6.7 3.7 | -35.5 -31.9 265 64 33 6.7 3.7
25000 -33.0 -27.4 265 70 36 6.7 3.7 | -33.5 -28.3 265 63 32 6.8 3.7
24000 -31.0 -23.8 265 69 36 6.7 3.7 | -31.4 -24.5 260 61 31 6.8 3.7
23000 -29.1 -20.4 265 66 34 6.4 3.5 | -29.3 -20.7 260 58 30 7.3 4.0
22000 -27.2 -17.0 265 63 33 6.4 3.5 | -27.1 -16.8 260 56 29 7.3 4.0
21000 -24.7 -12.5 260 59 31 7.8 4.3 | -24.3 -11.7 255 52 27 8.4 4.6
20000 -22.4 -8.3 265 55 28 7.8 4.3 | -21.8 -7.2 255 47 24 8.3 4.6
19500 -21.3 -6.3 265 53 27 7.8 4.3 | -20.6 -5.1 255 45 23 8.3 4.6
19000 -20.1 -4.2 265 51 26 7.7 4.2 | -19.4 -2.9 255 43 22 8.2 4.5
18500 -18.9 -2.0 265 48 25 8.5 4.7 | -18.1 -0.6 255 40 21 9.3 5.1
18000 -17.7 0.1 260 43 22 8.7 4.8 | -16.7 1.9 255 37 19 9.3 5.1
17500 -16.4 2.5 260 39 20 8.9 4.9 | -15.3 4.5 255 34 18 9.4 5.1
17000 -15.0 5.0 260 36 18 9.5 5.2 | -13.9 7.0 255 32 17 9.5 5.2
16500 -13.6 7.5 260 33 17 9.5 5.2 | -12.5 9.5 260 30 16 9.5 5.2
16000 -12.2 10.0 260 31 16 9.5 5.2 | -11.1 12.0 260 29 15 9.7 5.3
15500 -10.8 12.6 260 30 15 9.5 5.2 | -9.7 14.5 260 27 14 9.7 5.3
15000 -9.4 15.1 260 28 14 9.5 5.2 | -8.2 17.2 260 26 13 9.4 5.2
14500 -8.0 17.6 260 26 13 9.5 5.2 | -6.8 19.8 260 25 13 9.4 5.2
14000 -6.6 20.1 260 24 12 9.4 5.2 | -5.4 22.3 260 24 12 9.4 5.2
13500 -5.2 22.6 255 22 11 9.4 5.2 | -4.0 24.8 260 22 11 9.6 5.2
13000 -3.8 25.2 255 20 10 11.4 6.3 | -2.6 27.3 260 20 11 11.3 6.2
12500 -2.3 27.9 250 18 9 7.2 4.0 | -1.1 30.0 260 19 10 8.0 4.4
12000 -1.2 29.8 245 16 8 8.0 4.4 | 0.2 32.4 255 17 9 8.3 4.6
11750 -0.6 30.9 240 15 8 8.3 4.5 | 0.8 33.4 255 16 8 7.9 4.3
11500 0.1 32.2 235 14 7 9.3 5.1 | 1.4 34.5 250 16 8 8.7 4.8
11250 0.8 33.4 230 14 7 10.2 5.6 | 2.1 35.8 250 15 8 9.6 5.3
11000 1.6 34.9 225 13 7 9.6 5.3 | 2.7 36.9 245 14 7 8.9 4.9
10750 2.2 36.0 225 13 7 8.7 4.8 | 3.4 38.1 245 13 7 8.1 4.4
10500 2.9 37.2 220 13 6 8.8 4.8 | 4.0 39.2 240 13 7 8.3 4.6
10250 3.6 38.5 220 12 6 10.7 5.9 | 4.6 40.3 240 12 6 10.7 5.9
10000 4.4 39.9 215 12 6 11.0 6.0 | 5.5 41.9 235 12 6 10.9 6.0
9750 5.2 41.4 215 12 6 9.6 5.3 | 6.2 43.2 235 11 6 9.4 5.2
9500 5.9 42.6 210 12 6 9.2 5.1 | 6.9 44.4 230 11 6 9.1 5.0
9250 6.6 43.9 210 11 6 10.2 5.6 | 7.6 45.7 230 10 5 10.3 5.6
9000 7.4 45.3 205 11 6 10.8 5.9 | 8.4 47.1 225 10 5 10.6 5.8
8750 8.2 46.8 205 11 6 10.0 5.5 | 9.1 48.4 225 10 5 9.5 5.2
8500 8.9 48.0 205 11 6 10.2 5.6 | 9.9 49.8 220 9 5 9.8 5.3
8250 9.7 49.5 200 11 6 9.8 5.4 | 10.6 51.1 220 9 5 9.1 5.0
8000 10.6 51.1 195 10 5 17.1 9.4 | 11.3 52.3 215 8 4 11.9 6.5
7750 12.3 54.1 195 10 5 30.1 16.5 | 12.4 54.3 210 8 4 18.2 10.0
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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