Soaring Guidance
Issued by NWS Pueblo, CO
Issued by NWS Pueblo, CO
199
UXUS97 KPUB 061356
SRGPUB
Soaring Forecast
National Weather Service Pueblo, Colorado
0656 MST Wednesday, November 6, 2024
This forecast is for the Air Force Academy for Wednesday, November 6, 2024:
If the trigger temperature of 29.4 F/-1.4 C is reached...then
Thermal Soaring Index....................... Poor
Maximum rate of lift........................ 0 ft/min (0.0 m/s)
Maximum height of thermals.................. 10180 ft MSL (2546 ft AGL)
Forecast maximum temperature................... 27.0 F/-3.2 C
Time of trigger temperature.................... None
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................. None
Thermal soaring outlook for Thursday 11/07..... Poor
Wave Soaring Index............................. Not available
Remarks...
Sunrise/Sunset.................... 06:33:03 / 16:52:45 MST
Total possible sunshine........... 10 hr 19 min 42 sec (619 min 42 sec)
Altitude of sun at 11:42:54 MST... 34.58 degrees
Upper air data from numerical model forecast valid on 11/06/2024 at 0500 MST
Freezing level.................. Entire airmass below 32 F / 0 C
Convective condensation level... 11030 ft MSL (3396 ft AGL)
Lifted condensation level....... 10679 ft MSL (3044 ft AGL)
Lifted index.................... +9.1
K index......................... +8.2
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 -54.2 -65.6 250 25 13 1.3 0.7 M M M M M
45000 -52.3 -62.1 250 35 18 1.2 0.7 M M M M M
40000 -49.0 -56.2 230 44 23 2.2 1.2 M M M M M
38000 -47.9 -54.2 225 49 25 0.6 0.3 M M M M M
36000 -47.6 -53.7 225 55 28 0.5 0.3 M M M M M
34000 -47.3 -53.1 225 61 31 0.6 0.3 M M M M M
32000 -47.2 -53.0 225 72 37 0.0 0.0 M M M M M
30000 -47.2 -53.0 220 86 44 -0.4 -0.2 M M M M M
29000 -46.3 -51.3 225 84 43 4.8 2.6 20.3 68.6 17.9 M M
28000 -44.8 -48.6 225 77 40 4.8 2.6 18.3 65.0 16.5 M M
27000 -43.4 -46.1 225 71 37 4.8 2.6 16.5 61.7 15.3 M M
26000 -41.8 -43.2 225 64 33 6.7 3.7 14.9 58.8 14.2 M M
25000 -39.4 -38.9 220 50 26 6.5 3.6 13.3 55.9 13.1 M M
24000 -37.4 -35.3 215 39 20 6.6 3.6 12.2 53.9 12.3 M M
23000 -35.1 -31.2 210 32 17 9.2 5.0 11.5 52.7 11.9 M M
22000 -32.4 -26.3 210 32 16 9.2 5.1 11.2 52.2 11.8 M M
21000 -29.6 -21.3 210 31 16 9.5 5.2 11.1 52.0 11.8 M M
20000 -27.4 -17.3 205 28 15 6.7 3.7 10.3 50.5 11.2 M M
19500 -26.4 -15.5 200 27 14 6.7 3.7 9.7 49.5 10.8 M M
19000 -25.4 -13.7 200 25 13 6.7 3.7 9.2 48.6 10.4 M M
18500 -24.4 -11.9 195 23 12 6.6 3.6 8.7 47.7 10.0 M M
18000 -23.4 -10.1 185 22 11 7.8 4.3 8.3 46.9 9.7 M M
17500 -22.2 -8.0 185 21 11 7.9 4.3 8.0 46.3 9.4 M M
17000 -21.0 -5.8 180 20 10 7.5 4.1 7.7 45.8 9.2 M M
16500 -20.0 -4.0 170 18 9 7.0 3.9 7.2 45.0 8.8 M M
16000 -18.9 -2.0 165 15 8 6.9 3.8 6.8 44.2 8.5 M M
15500 -18.1 -0.6 155 13 7 4.7 2.6 6.1 43.0 7.9 M M
15000 -17.4 0.7 135 11 6 5.0 2.7 5.3 41.5 7.2 M M
14500 -16.7 1.9 115 11 6 3.6 2.0 4.4 39.9 6.4 M M
14000 -16.2 2.8 095 12 6 3.7 2.0 3.4 38.1 5.5 M M
13500 -15.7 3.7 080 13 7 2.7 1.5 2.4 36.3 4.6 M M
13000 -15.3 4.5 055 14 7 2.4 1.3 1.2 34.2 3.5 M M
12500 -14.8 5.4 045 17 9 4.7 2.6 0.2 32.4 2.6 M M
12000 -14.1 6.6 030 21 11 4.4 2.4 -0.6 31.0 1.8 M M
11750 -13.8 7.2 025 23 12 5.5 3.0 -1.0 30.3 1.5 M M
11500 -13.3 8.1 025 25 13 8.2 4.5 -1.2 29.9 1.2 M M
11250 -12.6 9.3 020 26 13 7.9 4.3 -1.3 29.7 1.1 M M
11000 -12.1 10.2 020 27 14 7.1 3.9 -1.5 29.3 0.9 M M
10750 -11.6 11.1 020 28 14 6.9 3.8 -1.7 29.0 0.7 M M
10500 -11.1 12.0 020 29 15 5.6 3.1 -2.0 28.5 0.4 M M
10250 -10.7 12.7 015 31 16 6.4 3.5 -2.3 27.9 0.1 M M
10000 -10.2 13.6 015 33 17 7.8 4.3 -2.5 27.6 -0.1 207 1.1
9750 -9.6 14.7 015 34 17 8.1 4.4 -2.6 27.3 -0.2 182 0.9
9500 -9.0 15.8 015 33 17 8.2 4.5 -2.7 27.1 -0.4 157 0.8
9250 -8.4 16.9 010 33 17 8.0 4.4 -2.9 26.9 -0.5 132 0.7
9000 -7.9 17.8 010 33 17 7.0 3.9 -3.0 26.6 -0.7 108 0.5
8750 -7.4 18.7 010 31 16 6.2 3.4 -3.3 26.1 -0.9 86 0.4
8500 -6.9 19.6 005 29 15 6.2 3.4 -3.5 25.6 -1.2 65 0.3
8250 -6.1 21.0 355 25 13 4.2 2.3 -4.1 24.6 -1.8 24 0.1
8000 -5.9 21.4 350 19 10 1.0 0.5 -4.7 23.6 -2.4 12 0.1
7750 -5.6 21.9 340 13 7 9.4 5.2 -5.1 22.7 -2.9 M M
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 * * * * * *
11/06/2024 at 0800 MST | 11/06/2024 at 1100 MST
|
CAPE... +17.2 LI... +3.6 | CAPE... +24.0 LI... +2.7
CINH... 0.0 K Index... +11.0 | CINH... 0.0 K Index... +8.5
|
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 -54.4 -65.9 240 17 9 2.7 1.5 | -53.4 -64.1 230 18 9 2.4 1.3
45000 -50.1 -58.2 245 24 13 2.7 1.5 | -49.8 -57.6 225 21 11 2.4 1.3
40000 -47.7 -53.9 235 42 21 1.5 0.8 | -48.2 -54.8 225 31 16 1.0 0.6
38000 -46.9 -52.4 230 48 25 0.8 0.4 | -47.5 -53.5 225 36 19 1.1 0.6
36000 -46.5 -51.7 225 53 27 0.8 0.4 | -46.8 -52.2 220 45 23 1.1 0.6
34000 -46.0 -50.8 220 59 30 0.8 0.4 | -46.1 -51.0 220 54 28 1.1 0.6
32000 -46.0 -50.8 220 69 35 -0.1 -0.0 | -45.8 -50.4 215 64 33 0.5 0.3
30000 -46.0 -50.8 220 79 41 -0.5 -0.3 | -45.5 -49.9 215 75 38 0.5 0.3
29000 -45.3 -49.5 225 80 41 3.2 1.8 | -44.6 -48.3 215 75 39 3.6 2.0
28000 -44.4 -47.9 225 80 41 3.2 1.8 | -43.5 -46.3 215 74 38 3.6 2.0
27000 -43.4 -46.1 225 80 41 3.2 1.8 | -42.4 -44.3 215 73 38 3.6 2.0
26000 -42.2 -44.0 225 77 40 6.0 3.3 | -41.2 -42.2 215 70 36 4.8 2.6
25000 -40.5 -40.9 225 65 33 5.7 3.1 | -39.8 -39.6 220 61 31 4.7 2.6
24000 -38.8 -37.8 230 53 27 5.7 3.1 | -38.4 -37.1 220 52 27 4.8 2.6
23000 -36.9 -34.4 230 42 22 8.2 4.5 | -36.7 -34.1 220 44 23 8.1 4.5
22000 -34.6 -30.3 220 34 18 7.9 4.3 | -33.7 -28.7 210 35 18 7.9 4.3
21000 -32.2 -26.0 215 27 14 7.9 4.4 | -31.4 -24.5 200 28 15 7.9 4.3
20000 -29.0 -20.2 205 21 11 8.9 4.9 | -28.9 -20.0 195 24 12 8.5 4.7
19500 -27.7 -17.9 205 20 10 8.9 4.9 | -27.6 -17.7 190 23 12 8.5 4.7
19000 -26.4 -15.5 200 18 9 9.0 4.9 | -26.3 -15.3 190 21 11 8.5 4.7
18500 -25.0 -13.0 200 17 9 9.4 5.1 | -25.1 -13.2 185 19 10 8.5 4.7
18000 -24.0 -11.2 195 15 8 5.4 2.9 | -23.8 -10.8 180 19 10 9.0 4.9
17500 -23.1 -9.6 175 13 7 5.7 3.1 | -22.4 -8.3 185 19 10 9.1 5.0
17000 -22.3 -8.1 160 13 7 5.9 3.2 | -21.2 -6.2 185 18 9 6.2 3.4
16500 -21.4 -6.5 140 12 6 5.9 3.2 | -20.4 -4.7 180 15 8 5.4 3.0
16000 -20.5 -4.9 120 13 7 5.5 3.0 | -19.6 -3.3 170 12 6 5.0 2.8
15500 -19.8 -3.6 105 14 7 4.2 2.3 | -19.0 -2.2 150 10 5 4.5 2.5
15000 -19.2 -2.6 090 16 8 4.2 2.3 | -18.3 -0.9 125 9 5 4.7 2.6
14500 -18.4 -1.1 080 17 9 6.4 3.5 | -17.5 0.5 105 10 5 6.3 3.4
14000 -17.5 0.5 070 19 10 6.1 3.3 | -16.6 2.1 090 12 6 6.2 3.4
13500 -16.5 2.3 060 21 11 7.4 4.1 | -15.8 3.6 075 15 7 4.2 2.3
13000 -15.4 4.3 055 22 11 6.8 3.7 | -15.2 4.6 065 18 9 4.1 2.3
12500 -14.1 6.6 055 23 12 8.5 4.7 | -14.4 6.1 060 20 10 5.6 3.1
12000 -13.2 8.2 050 26 13 6.4 3.5 | -13.8 7.2 050 24 13 4.0 2.2
11750 -12.8 9.0 050 28 14 5.9 3.3 | -13.5 7.7 050 27 14 3.6 2.0
11500 -12.4 9.7 050 29 15 5.6 3.1 | -13.2 8.2 045 29 15 3.2 1.8
11250 -12.0 10.4 045 30 15 4.5 2.4 | -13.0 8.6 045 31 16 2.7 1.5
11000 -11.7 10.9 045 32 16 3.9 2.1 | -12.8 9.0 040 32 17 2.1 1.2
10750 -11.4 11.5 040 33 17 3.2 1.8 | -12.6 9.3 040 34 17 3.3 1.8
10500 -11.2 11.8 035 35 18 1.8 1.0 | -12.4 9.7 035 35 18 3.7 2.0
10250 -11.1 12.0 030 36 19 3.6 2.0 | -12.1 10.2 030 36 19 4.2 2.3
10000 -10.7 12.7 030 37 19 6.0 3.3 | -11.7 10.9 025 38 19 5.9 3.2
9750 -10.2 13.6 025 37 19 7.3 4.0 | -11.2 11.8 020 38 19 6.7 3.7
9500 -9.7 14.5 020 36 19 7.6 4.2 | -10.7 12.7 020 37 19 6.8 3.7
9250 -9.1 15.6 020 35 18 8.2 4.5 | -10.2 13.6 015 36 19 6.9 3.8
9000 -8.4 16.9 015 35 18 9.6 5.2 | -9.7 14.5 015 36 18 8.5 4.7
8750 -7.8 18.0 015 33 17 9.1 5.0 | -9.0 15.8 010 33 17 9.5 5.2
8500 -7.1 19.2 010 32 16 8.2 4.5 | -8.3 17.1 010 31 16 9.1 5.0
8250 -6.5 20.3 010 30 15 9.1 5.0 | -7.7 18.1 010 29 15 9.8 5.4
8000 -5.8 21.6 010 28 15 10.2 5.6 | -6.8 19.8 005 28 14 14.1 7.8
7750 -5.1 22.8 005 22 11 10.1 5.5 | -5.6 21.9 005 23 12 19.6 10.7
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
11/06/2024 at 1400 MST | 11/06/2024 at 1700 MST
|
CAPE... +26.6 LI... +2.7 | CAPE... +1.4 LI... +3.5
CINH... -0.0 K Index... +10.6 | CINH... -0.6 K Index... +9.7
|
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 -54.2 -65.6 245 14 7 2.4 1.3 | -55.3 -67.5 250 10 5 2.5 1.4
45000 -50.6 -59.1 230 21 11 2.4 1.3 | -51.4 -60.5 245 18 9 2.4 1.3
40000 -47.5 -53.5 225 31 16 2.1 1.1 | -47.9 -54.2 230 25 13 2.4 1.3
38000 -46.6 -51.9 225 38 19 -0.1 -0.0 | -46.6 -51.9 230 32 16 1.5 0.8
36000 -46.6 -51.9 225 48 25 -0.0 -0.0 | -45.7 -50.3 230 42 22 1.5 0.8
34000 -46.6 -51.9 225 58 30 0.2 0.1 | -44.8 -48.6 225 53 27 1.4 0.8
32000 -45.7 -50.3 220 67 34 1.6 0.9 | -44.5 -48.1 220 68 35 0.4 0.2
30000 -44.8 -48.6 220 75 39 1.7 0.9 | -44.3 -47.7 220 82 42 1.4 0.8
29000 -44.0 -47.2 220 76 39 2.7 1.5 | -43.6 -46.5 215 77 39 2.2 1.2
28000 -43.2 -45.8 220 77 40 2.7 1.5 | -43.0 -45.4 215 71 37 2.2 1.2
27000 -42.4 -44.3 220 78 40 2.8 1.5 | -42.3 -44.1 215 66 34 2.2 1.2
26000 -41.3 -42.3 220 73 38 5.3 2.9 | -40.9 -41.6 210 59 30 6.7 3.6
25000 -39.8 -39.6 220 61 31 5.2 2.8 | -38.9 -38.0 205 50 26 6.8 3.7
24000 -38.2 -36.8 225 49 25 5.2 2.9 | -36.9 -34.4 200 42 21 6.8 3.8
23000 -35.6 -32.1 220 38 20 8.9 4.9 | -34.6 -30.3 190 35 18 8.4 4.6
22000 -32.9 -27.2 210 34 18 9.0 4.9 | -32.1 -25.8 190 31 16 8.4 4.6
21000 -30.3 -22.5 195 32 17 8.9 4.9 | -29.6 -21.3 185 27 14 8.5 4.7
20000 -27.7 -17.9 195 29 15 8.7 4.8 | -27.1 -16.8 180 25 13 8.3 4.5
19500 -26.4 -15.5 190 28 14 8.7 4.8 | -25.9 -14.6 180 25 13 8.3 4.5
19000 -25.1 -13.2 190 26 14 8.7 4.8 | -24.0 -11.2 180 25 13 8.3 4.5
18500 -23.8 -10.8 190 25 13 8.6 4.7 | -22.8 -9.0 180 24 13 7.8 4.3
18000 -22.8 -9.0 190 23 12 5.9 3.2 | -21.8 -7.2 175 22 11 6.9 3.8
17500 -21.8 -7.2 190 20 10 6.0 3.3 | -20.7 -5.3 170 19 10 7.0 3.9
17000 -20.9 -5.6 190 18 9 7.5 4.1 | -19.8 -3.6 165 17 9 5.3 2.9
16500 -19.7 -3.5 185 17 9 7.7 4.2 | -19.0 -2.2 160 14 7 5.5 3.0
16000 -18.6 -1.5 185 16 8 7.3 4.0 | -18.2 -0.8 150 11 6 5.3 2.9
15500 -17.6 0.3 185 15 8 6.6 3.6 | -17.4 0.7 135 8 4 5.2 2.9
15000 -16.6 2.1 190 13 7 6.4 3.5 | -16.7 1.9 115 6 3 5.1 2.8
14500 -15.7 3.7 190 10 5 5.3 2.9 | -15.9 3.4 100 6 3 4.9 2.7
14000 -14.9 5.2 180 6 3 5.4 3.0 | -15.2 4.6 085 7 3 4.8 2.6
13500 -14.3 6.3 135 3 2 3.5 1.9 | -14.6 5.7 070 9 4 4.3 2.3
13000 -13.8 7.2 080 5 3 3.7 2.1 | -13.9 7.0 060 11 6 3.9 2.1
12500 -13.4 7.9 065 7 4 1.0 0.5 | -13.6 7.5 055 15 8 1.1 0.6
12000 -13.4 7.9 045 15 8 -1.2 -0.6 | -13.4 7.9 045 20 10 1.6 0.9
11750 -13.5 7.7 040 20 10 0.3 0.2 | -13.3 8.1 040 22 11 3.0 1.7
11500 -13.4 7.9 040 22 11 1.4 0.8 | -13.0 8.6 040 23 12 3.6 1.9
11250 -13.3 8.1 035 24 12 2.4 1.3 | -12.7 9.1 035 24 13 3.7 2.0
11000 -13.0 8.6 035 27 14 3.7 2.0 | -12.5 9.5 035 26 14 3.8 2.1
10750 -12.8 9.0 030 29 15 3.9 2.1 | -12.2 10.0 030 28 14 3.6 2.0
10500 -12.5 9.5 025 31 16 4.1 2.3 | -11.9 10.6 030 29 15 3.2 1.8
10250 -12.1 10.2 020 34 17 4.8 2.6 | -11.7 10.9 025 31 16 4.6 2.5
10000 -11.7 10.9 020 36 18 6.3 3.5 | -11.2 11.8 025 32 17 6.5 3.5
9750 -11.2 11.8 015 36 18 6.8 3.7 | -10.8 12.6 020 32 17 6.3 3.4
9500 -10.8 12.6 015 35 18 6.3 3.5 | -10.3 13.5 015 32 17 6.4 3.5
9250 -10.3 13.5 010 34 17 7.9 4.3 | -9.9 14.2 015 32 17 5.9 3.2
9000 -9.6 14.7 010 33 17 9.7 5.3 | -9.4 15.1 010 32 17 7.1 3.9
8750 -8.9 16.0 005 31 16 9.4 5.2 | -8.8 16.2 010 31 16 8.5 4.6
8500 -8.2 17.2 005 30 15 9.0 4.9 | -8.2 17.2 005 30 15 8.2 4.5
8250 -7.5 18.5 005 29 15 10.0 5.5 | -7.6 18.3 360 28 15 8.0 4.4
8000 -6.7 19.9 360 27 14 14.1 7.7 | -7.0 19.4 360 27 14 8.2 4.5
7750 -5.5 22.1 360 23 12 18.1 9.9 | -6.4 20.5 360 21 11 9.6 5.3
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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