Soaring Guidance
Issued by NWS Pueblo, CO
Issued by NWS Pueblo, CO
898
UXUS97 KPUB 081221
SRGPUB
Soaring Forecast
National Weather Service Pueblo, Colorado
0521 MST Friday, November 8, 2024
This forecast is for the Air Force Academy for Friday, November 8, 2024:
If the trigger temperature of 37.1 F/2.8 C is reached...then
Thermal Soaring Index....................... Poor
Maximum rate of lift........................ 0 ft/min (0.0 m/s)
Maximum height of thermals.................. 9454 ft MSL (1835 ft AGL)
Forecast maximum temperature................... 33.0 F/1.0 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................. 8022 ft MSL (403 ft AGL)
Thermal soaring outlook for Saturday 11/09..... Poor
Wave Soaring Index............................. Not available
Remarks...
Sunrise/Sunset.................... 06:35:16 / 16:50:48 MST
Total possible sunshine........... 10 hr 15 min 32 sec (615 min 32 sec)
Altitude of sun at 11:43:02 MST... 34.00 degrees
Upper air data from numerical model forecast valid on 11/08/2024 at 0500 MST
Freezing level.................. Entire airmass below 32 F / 0 C
Convective condensation level... 11274 ft MSL (3655 ft AGL)
Lifted condensation level....... 10486 ft MSL (2867 ft AGL)
Lifted index.................... +11.3
K index......................... +9.1
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 -56.7 -70.1 210 12 6 4.3 2.4 M M M M M
45000 -50.5 -58.9 185 10 5 2.0 1.1 M M M M M
40000 -47.6 -53.7 145 10 5 2.0 1.1 M M M M M
38000 -46.7 -52.1 160 18 10 0.9 0.5 M M M M M
36000 -46.2 -51.2 165 32 16 0.9 0.5 M M M M M
34000 -45.7 -50.3 170 45 23 0.7 0.4 M M M M M
32000 -45.3 -49.5 170 58 30 0.7 0.4 M M M M M
30000 -44.0 -47.2 165 67 35 7.6 4.2 25.2 77.3 18.9 M M
29000 -41.7 -43.1 165 66 34 7.6 4.2 24.2 75.5 18.4 M M
28000 -39.5 -39.1 160 64 33 7.6 4.2 23.4 74.1 18.0 M M
27000 -37.2 -35.0 155 63 33 8.4 4.6 22.7 72.9 17.6 M M
26000 -34.3 -29.7 150 64 33 9.8 5.4 22.6 72.6 17.7 M M
25000 -31.4 -24.5 150 65 33 9.8 5.4 22.6 72.6 17.9 M M
24000 -28.5 -19.3 150 65 34 9.7 5.3 22.7 72.8 18.2 M M
23000 -25.7 -14.3 145 64 33 7.2 3.9 21.6 70.9 17.6 M M
22000 -23.5 -10.3 140 62 32 7.2 4.0 20.7 69.3 17.0 M M
21000 -21.5 -6.7 140 60 31 5.3 2.9 19.7 67.5 16.3 M M
20000 -19.9 -3.8 140 55 28 5.4 3.0 18.2 64.7 15.1 M M
19500 -19.1 -2.4 135 52 27 5.4 3.0 17.4 63.4 14.6 M M
19000 -18.3 -0.9 135 49 25 5.4 2.9 16.7 62.1 14.0 M M
18500 -17.4 0.7 135 47 24 7.0 3.8 16.1 61.0 13.5 M M
18000 -16.4 2.5 140 45 23 7.3 4.0 15.7 60.3 13.2 M M
17500 -15.3 4.5 140 44 22 6.2 3.4 15.3 59.6 12.9 M M
17000 -14.8 5.4 155 39 20 1.2 0.7 14.2 57.5 12.0 M M
16500 -14.6 5.7 170 37 19 1.3 0.7 12.8 55.1 10.8 M M
16000 -14.3 6.3 185 35 18 3.3 1.8 11.6 52.8 9.7 M M
15500 -13.8 7.2 190 29 15 3.2 1.8 10.5 50.9 8.8 M M
15000 -13.3 8.1 195 24 12 3.4 1.8 9.4 49.0 7.9 M M
14500 -12.8 9.0 190 17 9 3.4 1.9 8.4 47.1 6.9 M M
14000 -12.3 9.9 180 11 5 2.8 1.6 7.4 45.3 6.0 M M
13500 -12.0 10.4 155 9 5 2.4 1.3 6.2 43.1 4.9 M M
13000 -11.6 11.1 130 10 5 3.4 1.9 5.0 41.0 3.8 M M
12500 -10.9 12.4 125 13 7 5.4 3.0 4.2 39.6 3.1 M M
12000 -10.1 13.8 120 16 8 6.4 3.5 3.6 38.5 2.5 M M
11750 -9.6 14.7 120 16 8 7.5 4.1 3.4 38.1 2.3 M M
11500 -9.0 15.8 125 17 9 7.5 4.1 3.2 37.8 2.1 M M
11250 -8.5 16.7 125 17 9 8.3 4.6 3.0 37.5 2.0 M M
11000 -7.8 18.0 125 17 9 7.7 4.2 2.9 37.3 1.8 M M
10750 -7.3 18.9 125 16 8 6.5 3.6 2.7 36.9 1.6 M M
10500 -6.9 19.6 125 15 8 6.9 3.8 2.5 36.5 1.4 M M
10250 -6.4 20.5 125 13 7 6.4 3.5 2.2 36.0 1.1 M M
10000 -5.9 21.4 130 12 6 5.7 3.1 2.0 35.5 0.8 M M
9750 -5.5 22.1 130 11 6 5.4 2.9 1.6 34.9 0.5 M M
9500 -5.1 22.8 130 9 5 6.3 3.5 1.3 34.3 0.2 M M
9250 -4.7 23.5 135 8 4 3.0 1.6 1.0 33.8 -0.1 148 0.7
9000 -4.7 23.5 130 7 4 0.9 0.5 0.3 32.6 -0.8 138 0.7
8750 -4.5 23.9 125 6 3 2.9 1.6 -0.3 31.5 -1.4 126 0.6
8500 -4.3 24.3 120 4 2 2.2 1.2 -0.8 30.5 -1.9 113 0.6
8250 -4.1 24.6 105 3 2 3.1 1.7 -1.4 29.6 -2.5 100 0.5
8000 -3.8 25.2 080 3 1 5.6 3.1 -1.8 28.8 -2.9 84 0.4
7750 -3.3 26.1 040 2 1 7.6 4.1 -2.0 28.4 -3.2 61 0.3
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 * * * * * *
11/08/2024 at 0800 MST | 11/08/2024 at 1100 MST
|
CAPE... +0.6 LI... +4.9 | CAPE... +3.0 LI... +4.0
CINH... 0.0 K Index... +15.6 | CINH... 0.0 K Index... +13.7
|
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 -56.6 -69.9 245 12 6 4.2 2.3 | -57.1 -70.8 275 11 6 4.1 2.3
45000 -50.6 -59.1 210 12 6 2.5 1.4 | -51.2 -60.2 245 9 5 2.4 1.3
40000 -46.7 -52.1 170 20 10 2.4 1.3 | -47.5 -53.5 180 21 11 2.2 1.2
38000 -45.9 -50.6 165 30 16 1.0 0.6 | -47.5 -53.5 155 35 18 -0.6 -0.3
36000 -45.3 -49.5 160 43 22 1.0 0.6 | -47.9 -54.2 145 55 28 -0.6 -0.3
34000 -44.7 -48.5 160 55 28 0.8 0.4 | -47.3 -53.1 135 70 36 4.8 2.6
32000 -44.3 -47.7 160 64 33 0.8 0.4 | -44.3 -47.7 130 70 36 4.9 2.7
30000 -43.0 -45.4 160 71 36 6.5 3.6 | -40.7 -41.3 125 69 35 8.6 4.7
29000 -41.1 -42.0 155 70 36 6.5 3.6 | -38.1 -36.6 125 63 32 8.7 4.8
28000 -39.2 -38.6 155 68 35 6.5 3.6 | -35.5 -31.9 125 57 30 8.7 4.8
27000 -37.2 -35.0 155 67 35 7.5 4.1 | -32.9 -27.2 125 52 27 7.8 4.3
26000 -34.5 -30.1 155 66 34 9.0 4.9 | -30.7 -23.3 130 50 26 7.2 4.0
25000 -31.9 -25.4 155 65 33 9.0 4.9 | -28.6 -19.5 140 48 25 7.2 4.0
24000 -28.5 -19.3 155 63 32 8.5 4.6 | -26.4 -15.5 145 47 24 7.2 4.0
23000 -26.1 -15.0 155 62 32 8.2 4.5 | -24.3 -11.7 140 47 24 7.1 3.9
22000 -23.6 -10.5 155 61 32 8.3 4.5 | -21.7 -7.1 140 48 25 7.2 3.9
21000 -21.3 -6.3 155 59 31 6.4 3.5 | -19.7 -3.5 135 47 24 5.4 3.0
20000 -19.4 -2.9 150 54 28 6.5 3.6 | -18.0 -0.4 125 45 23 5.6 3.1
19500 -18.4 -1.1 145 52 27 6.5 3.6 | -17.2 1.0 120 44 23 5.6 3.1
19000 -17.5 0.5 140 49 25 6.6 3.6 | -16.4 2.5 115 44 23 5.6 3.1
18500 -16.5 2.3 135 47 24 6.3 3.5 | -15.6 3.9 110 44 22 5.1 2.8
18000 -15.6 3.9 130 47 24 6.2 3.4 | -14.8 5.4 105 42 22 5.0 2.7
17500 -14.7 5.5 120 48 25 5.2 2.9 | -14.1 6.6 100 41 21 5.2 2.9
17000 -14.3 6.3 110 45 23 1.3 0.7 | -13.3 8.1 100 40 21 6.0 3.3
16500 -14.1 6.6 100 43 22 1.1 0.6 | -12.4 9.7 100 39 20 6.1 3.4
16000 -13.7 7.3 090 41 21 4.9 2.7 | -11.7 10.9 095 38 19 4.0 2.2
15500 -13.0 8.6 085 37 19 4.7 2.6 | -11.0 12.2 095 36 18 4.1 2.3
15000 -12.3 9.9 085 33 17 4.4 2.4 | -10.5 13.1 090 33 17 3.7 2.0
14500 -11.7 10.9 080 26 13 4.4 2.4 | -9.9 14.2 090 31 16 3.5 1.9
14000 -11.0 12.2 075 19 10 5.1 2.8 | -9.4 15.1 085 29 15 4.1 2.2
13500 -10.2 13.6 070 16 8 5.9 3.2 | -8.8 16.2 080 27 14 4.6 2.5
13000 -9.3 15.3 060 14 7 6.3 3.5 | -8.1 17.4 075 26 13 5.1 2.8
12500 -8.3 17.1 060 13 7 5.7 3.1 | -7.3 18.9 065 25 13 4.6 2.5
12000 -7.6 18.3 060 14 7 4.8 2.6 | -6.7 19.9 060 24 13 3.6 2.0
11750 -7.3 18.9 060 15 7 4.3 2.4 | -6.5 20.3 055 24 12 3.0 1.6
11500 -6.9 19.6 060 15 7 4.3 2.3 | -6.2 20.8 050 24 12 2.9 1.6
11250 -6.7 19.9 065 15 7 3.5 1.9 | -6.0 21.2 045 23 12 3.4 1.9
11000 -6.4 20.5 065 15 8 3.7 2.0 | -5.8 21.6 040 22 11 2.9 1.6
10750 -6.1 21.0 065 14 7 4.5 2.5 | -5.6 21.9 035 22 11 2.0 1.1
10500 -5.8 21.6 065 13 6 4.3 2.3 | -5.5 22.1 030 21 11 1.7 0.9
10250 -5.5 22.1 065 11 6 5.1 2.8 | -5.3 22.5 025 20 11 2.8 1.5
10000 -5.0 23.0 070 10 5 6.4 3.5 | -5.1 22.8 020 20 10 1.8 1.0
9750 -4.6 23.7 065 10 5 6.1 3.3 | -5.1 22.8 015 20 10 -0.0 -0.0
9500 -4.1 24.6 055 10 5 7.2 3.9 | -5.1 22.8 010 20 10 0.2 0.1
9250 -3.7 25.3 050 10 5 3.2 1.8 | -5.0 23.0 005 21 11 1.0 0.5
9000 -3.7 25.3 040 10 5 -0.9 -0.5 | -4.9 23.2 360 21 11 2.5 1.4
8750 -3.7 25.3 025 10 5 0.1 0.1 | -4.7 23.5 360 21 11 2.7 1.5
8500 -3.7 25.3 010 11 5 -0.6 -0.3 | -4.5 23.9 355 20 10 2.5 1.4
8250 -3.7 25.3 360 12 6 1.2 0.7 | -4.3 24.3 350 20 10 3.1 1.7
8000 -2.9 26.8 350 11 6 8.6 4.7 | -3.9 25.0 350 19 10 7.4 4.1
7750 -2.3 27.9 340 9 5 5.6 3.1 | -3.2 26.2 350 15 8 12.6 6.9
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
11/08/2024 at 1400 MST | 11/08/2024 at 1700 MST
|
CAPE... +3.1 LI... +4.0 | CAPE... 0.0 LI... +4.1
CINH... 0.0 K Index... +11.8 | CINH... 0.0 K Index... +13.2
|
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 -57.1 -70.8 260 10 5 4.3 2.4 | -58.2 -72.8 260 13 7 4.1 2.2
45000 -50.8 -59.4 275 6 3 2.6 1.4 | -52.2 -62.0 265 9 5 3.9 2.1
40000 -46.9 -52.4 145 3 2 2.5 1.4 | -46.1 -51.0 050 5 2 3.8 2.1
38000 -45.9 -50.6 125 20 10 1.2 0.7 | -44.6 -48.3 100 14 7 2.1 1.2
36000 -45.2 -49.4 125 41 21 1.2 0.7 | -43.3 -45.9 110 27 14 2.1 1.2
34000 -44.3 -47.7 120 60 31 2.1 1.2 | -42.2 -44.0 110 43 22 0.8 0.4
32000 -43.0 -45.4 110 73 38 2.1 1.2 | -41.8 -43.2 100 67 34 0.7 0.4
30000 -40.9 -41.6 110 83 43 7.9 4.3 | -40.3 -40.5 100 85 44 9.0 5.0
29000 -38.5 -37.3 110 82 42 8.0 4.4 | -37.6 -35.7 100 83 43 9.0 4.9
28000 -36.1 -33.0 110 80 41 8.0 4.4 | -35.0 -31.0 095 80 41 9.0 4.9
27000 -33.7 -28.7 115 79 40 7.5 4.1 | -32.3 -26.1 095 77 40 8.2 4.5
26000 -31.7 -25.1 115 74 38 6.5 3.5 | -30.9 -23.6 100 73 38 3.9 2.1
25000 -29.8 -21.6 120 70 36 6.5 3.5 | -29.7 -21.5 105 69 36 3.9 2.1
24000 -27.9 -18.2 120 66 34 6.5 3.6 | -28.5 -19.3 110 66 34 3.7 2.0
23000 -25.9 -14.6 125 60 31 6.5 3.5 | -26.9 -16.4 110 59 30 6.3 3.5
22000 -23.5 -10.3 125 53 27 6.4 3.5 | -24.5 -12.1 110 48 25 6.3 3.5
21000 -21.4 -6.5 130 47 24 8.9 4.9 | -22.6 -8.7 105 40 20 8.4 4.6
20000 -18.7 -1.7 125 41 21 9.0 4.9 | -19.9 -3.8 095 37 19 9.0 4.9
19500 -17.4 0.7 125 38 20 9.0 4.9 | -18.6 -1.5 090 36 18 9.0 5.0
19000 -16.1 3.0 125 35 18 9.0 5.0 | -17.3 0.9 085 35 18 9.1 5.0
18500 -14.8 5.4 120 33 17 8.0 4.4 | -16.0 3.2 080 35 18 9.0 5.0
18000 -13.7 7.3 120 32 16 7.6 4.2 | -14.7 5.5 080 34 17 9.0 4.9
17500 -12.6 9.3 115 30 16 7.3 4.0 | -13.4 7.9 080 33 17 9.1 5.0
17000 -11.9 10.6 115 30 15 3.9 2.1 | -12.3 9.9 080 32 17 5.2 2.8
16500 -11.3 11.7 115 30 15 4.3 2.3 | -11.5 11.3 085 31 16 5.7 3.1
16000 -10.8 12.6 115 30 15 2.7 1.5 | -10.9 12.4 085 31 16 1.3 0.7
15500 -10.4 13.3 115 28 15 2.5 1.4 | -10.9 12.4 085 29 15 -0.0 -0.0
15000 -10.0 14.0 110 27 14 2.5 1.3 | -10.9 12.4 085 28 14 0.5 0.3
14500 -9.7 14.5 105 26 13 2.4 1.3 | -10.7 12.7 085 27 14 1.5 0.8
14000 -9.3 15.3 100 25 13 2.4 1.3 | -10.5 13.1 080 26 13 2.1 1.1
13500 -9.0 15.8 090 24 12 2.4 1.3 | -9.9 14.2 080 25 13 5.1 2.8
13000 -8.6 16.5 080 23 12 2.5 1.4 | -9.2 15.4 085 25 13 4.9 2.7
12500 -8.2 17.2 075 23 12 2.6 1.4 | -8.5 16.7 085 25 13 3.2 1.7
12000 -7.8 18.0 070 22 11 2.4 1.3 | -8.2 17.2 080 27 14 2.1 1.1
11750 -7.7 18.1 065 22 11 2.2 1.2 | -8.1 17.4 075 28 14 -1.0 -0.5
11500 -7.5 18.5 060 22 12 2.1 1.2 | -8.3 17.1 070 28 14 -2.9 -1.6
11250 -7.3 18.9 055 23 12 2.6 1.4 | -8.4 16.9 065 28 14 -1.7 -0.9
11000 -7.1 19.2 050 23 12 2.7 1.5 | -8.5 16.7 055 27 14 -0.8 -0.4
10750 -7.0 19.4 045 24 12 2.3 1.3 | -8.5 16.7 045 27 14 2.8 1.5
10500 -6.8 19.8 040 25 13 2.0 1.1 | -8.1 17.4 040 26 14 4.7 2.6
10250 -6.6 20.1 040 25 13 2.7 1.5 | -7.8 18.0 030 27 14 5.0 2.7
10000 -6.4 20.5 030 26 13 3.6 2.0 | -7.4 18.7 025 28 14 5.8 3.2
9750 -6.1 21.0 030 27 14 3.8 2.1 | -7.0 19.4 025 29 15 4.8 2.6
9500 -5.8 21.6 025 27 14 3.5 1.9 | -6.7 19.9 025 30 16 4.2 2.3
9250 -5.6 21.9 020 28 14 4.6 2.5 | -6.4 20.5 020 32 16 5.3 2.9
9000 -5.2 22.6 015 28 14 4.8 2.6 | -5.9 21.4 020 33 17 5.4 3.0
8750 -4.9 23.2 015 27 14 3.7 2.0 | -5.6 21.9 015 32 17 4.2 2.3
8500 -4.6 23.7 010 27 14 4.0 2.2 | -5.3 22.5 010 31 16 4.3 2.4
8250 -4.3 24.3 005 27 14 3.9 2.1 | -5.0 23.0 005 31 16 4.2 2.3
8000 -3.9 25.0 360 26 13 8.0 4.4 | -4.6 23.7 360 30 15 5.9 3.3
7750 -3.1 26.4 360 20 10 14.8 8.1 | -4.1 24.6 360 23 12 9.0 4.9
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
________________________________________________________________________________
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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