Soaring Guidance
Issued by NWS Pueblo, CO
Issued by NWS Pueblo, CO
401
UXUS97 KPUB 211214
SRGPUB
Soaring Forecast
National Weather Service Pueblo, Colorado
0614 MDT Saturday, September 21, 2024
This forecast is for the Air Force Academy for Saturday, September 21, 2024:
If the trigger temperature of 70.1 F/21.1 C is reached...then
Thermal Soaring Index....................... Poor
Maximum rate of lift........................ 0 ft/min (0.0 m/s)
Maximum height of thermals.................. 9634 ft MSL (2020 ft AGL)
Forecast maximum temperature................... 66.0 F/19.3 C
Time of trigger temperature.................... None
Time of overdevelopment........................ 1200 MDT
Middle/high clouds during soaring window....... Broken/overcast opaque middle
Surface winds during soaring window............ Between 20 mph and 30 mph
Height of the -3 thermal index................. 8083 ft MSL (469 ft AGL)
Thermal soaring outlook for Sunday 09/22....... Poor
Wave Soaring Index............................. Not available
Remarks...
Sunrise/Sunset.................... 06:46:53 / 18:57:19 MDT
Total possible sunshine........... 12 hr 10 min 25 sec (730 min 25 sec)
Altitude of sun at 12:52:06 MDT... 51.26 degrees
Upper air data from numerical model forecast valid on 09/21/2024 at 0600 MDT
Freezing level.................. 14995 ft MSL (7381 ft AGL)
Convective condensation level... 19579 ft MSL (11965 ft AGL)
Lifted condensation level....... 17344 ft MSL (9730 ft AGL)
Lifted index.................... +4.0
K index......................... +16.3
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 -63.7 -82.7 240 49 25 3.0 1.6 M M M M M
45000 -58.3 -72.9 230 72 37 5.5 3.0 M M M M M
40000 -49.8 -57.6 230 87 45 5.1 2.8 M M M M M
38000 -46.7 -52.1 225 88 45 5.1 2.8 M M M M M
36000 -43.6 -46.5 225 88 45 5.2 2.8 M M M M M
34000 -39.8 -39.6 225 83 43 6.7 3.7 M M M M M
32000 -35.8 -32.4 225 77 40 6.7 3.7 M M M M M
30000 -32.2 -26.0 225 67 34 5.6 3.1 36.9 98.3 14.0 M M
29000 -30.5 -22.9 225 61 31 5.6 3.1 35.3 95.5 12.9 M M
28000 -28.8 -19.8 225 54 28 5.5 3.0 33.8 92.9 11.9 M M
27000 -27.0 -16.6 225 49 25 6.4 3.5 32.4 90.3 10.9 M M
26000 -25.1 -13.2 225 45 23 6.4 3.5 31.1 88.0 10.0 M M
25000 -23.2 -9.8 220 40 21 6.5 3.6 30.0 85.9 9.1 M M
24000 -20.3 -4.5 220 35 18 8.3 4.5 28.9 84.1 8.4 M M
23000 -17.9 -0.2 220 31 16 8.2 4.5 28.4 83.1 8.0 M M
22000 -15.4 4.3 220 27 14 8.1 4.4 27.9 82.3 7.7 M M
21000 -13.5 7.7 215 24 12 5.9 3.3 26.7 80.0 6.7 M M
20000 -11.7 10.9 210 21 11 6.0 3.3 25.4 77.7 5.6 M M
19500 -10.8 12.6 210 20 10 6.0 3.3 24.8 76.6 5.1 M M
19000 -9.9 14.2 205 19 10 7.3 4.0 24.3 75.7 4.6 M M
18500 -8.8 16.2 205 19 10 7.6 4.2 23.9 75.0 4.2 M M
18000 -7.8 18.0 205 19 10 7.9 4.4 23.5 74.4 3.9 M M
17500 -6.5 20.3 205 18 9 8.9 4.9 23.3 74.0 3.7 M M
17000 -5.2 22.6 205 16 8 8.9 4.9 23.2 73.7 3.5 M M
16500 -4.0 24.8 205 15 8 9.0 5.0 23.0 73.5 3.3 M M
16000 -2.7 27.1 210 15 8 9.1 5.0 22.9 73.3 3.2 M M
15500 -1.3 29.7 215 14 7 9.1 5.0 22.8 73.1 3.1 M M
15000 -0.0 32.0 225 14 7 9.0 5.0 22.7 72.8 2.9 M M
14500 1.3 34.3 235 14 7 9.1 5.0 22.6 72.6 2.8 M M
14000 2.7 36.9 245 14 7 9.5 5.2 22.5 72.5 2.7 M M
13500 4.1 39.4 250 13 7 9.4 5.1 22.5 72.4 2.7 M M
13000 5.6 42.1 260 12 6 10.4 5.7 22.5 72.5 2.8 M M
12500 7.0 44.6 265 10 5 7.9 4.4 22.4 72.3 2.7 M M
12000 8.2 46.8 280 8 4 7.6 4.2 22.1 71.7 2.4 M M
11750 8.8 47.8 290 7 3 7.6 4.1 21.9 71.5 2.3 M M
11500 9.3 48.7 305 6 3 6.9 3.8 21.7 71.1 2.1 M M
11250 9.8 49.6 325 6 3 6.3 3.5 21.5 70.7 1.9 M M
11000 10.3 50.5 345 7 3 6.2 3.4 21.2 70.2 1.7 M M
10750 10.7 51.3 355 8 4 6.2 3.4 20.9 69.6 1.4 M M
10500 11.2 52.2 005 10 5 5.9 3.3 20.6 69.1 1.1 M M
10250 11.6 52.9 010 12 6 5.8 3.2 20.3 68.6 0.8 M M
10000 12.0 53.6 010 13 7 6.2 3.4 20.0 68.1 0.5 M M
9750 12.5 54.5 015 15 8 6.3 3.5 19.8 67.6 0.2 M M
9500 13.0 55.4 015 16 8 6.3 3.5 19.5 67.1 -0.1 174 0.9
9250 13.4 56.1 015 18 9 6.1 3.3 19.2 66.6 -0.3 153 0.8
9000 13.9 57.0 015 18 9 6.0 3.3 18.9 66.1 -0.6 133 0.7
8750 14.3 57.7 015 18 9 5.7 3.1 18.7 65.6 -0.9 112 0.6
8500 14.8 58.6 010 18 9 7.2 4.0 18.4 65.1 -1.2 91 0.5
8250 15.2 59.4 010 18 9 1.3 0.7 18.1 64.6 -1.5 70 0.4
8000 14.7 58.5 360 17 9 -17.6 -9.6 16.8 62.2 -2.7 79 0.4
7750 12.8 55.0 345 11 6 -30.7 -16.9 14.1 57.4 -5.4 128 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 * * * * * *
09/21/2024 at 0900 MDT | 09/21/2024 at 1200 MDT
|
CAPE... 0.0 LI... -0.3 | CAPE... 0.0 LI... -0.0
CINH... 0.0 K Index... +17.4 | CINH... 0.0 K Index... +19.2
|
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 -62.3 -80.1 235 46 24 2.7 1.5 | -60.8 -77.4 225 46 24 2.2 1.2
45000 -57.5 -71.5 230 74 38 4.9 2.7 | -56.7 -70.1 225 78 40 3.9 2.2
40000 -49.8 -57.6 225 92 47 4.7 2.6 | -50.8 -59.4 220 102 52 4.7 2.6
38000 -47.0 -52.6 220 93 48 4.7 2.6 | -48.0 -54.4 215 98 50 4.7 2.6
36000 -44.1 -47.4 220 94 48 4.8 2.6 | -45.2 -49.4 215 95 49 4.7 2.6
34000 -40.7 -41.3 220 88 45 6.0 3.3 | -42.0 -43.6 210 88 45 5.8 3.2
32000 -37.1 -34.8 220 80 41 6.0 3.3 | -38.0 -36.4 205 80 41 5.9 3.2
30000 -33.7 -28.7 220 67 34 5.5 3.0 | -33.5 -28.3 205 70 36 8.3 4.5
29000 -32.1 -25.8 220 59 30 5.5 3.0 | -31.0 -23.8 205 65 34 8.3 4.6
28000 -30.4 -22.7 215 52 27 5.3 2.9 | -28.6 -19.5 200 60 31 8.3 4.6
27000 -28.3 -18.9 215 47 24 7.8 4.3 | -26.3 -15.3 205 57 29 7.5 4.1
26000 -25.9 -14.6 215 43 22 7.8 4.3 | -24.1 -11.4 205 53 28 7.6 4.1
25000 -23.0 -9.4 210 38 20 7.8 4.3 | -21.9 -7.4 210 50 26 7.6 4.2
24000 -20.7 -5.3 210 34 18 7.8 4.3 | -19.8 -3.6 210 45 23 6.5 3.6
23000 -18.3 -0.9 210 30 15 7.8 4.3 | -17.9 -0.2 215 38 20 6.5 3.6
22000 -16.0 3.2 210 25 13 7.7 4.2 | -16.0 3.2 220 32 16 6.6 3.6
21000 -14.2 6.4 205 24 13 5.6 3.1 | -14.3 6.3 225 26 13 5.7 3.1
20000 -12.6 9.3 200 25 13 5.9 3.2 | -12.6 9.3 225 21 11 5.7 3.1
19500 -11.7 10.9 200 25 13 5.9 3.2 | -11.7 10.9 230 19 10 5.7 3.1
19000 -10.8 12.6 200 25 13 8.3 4.6 | -10.9 12.4 230 17 9 6.2 3.4
18500 -9.5 14.9 200 23 12 8.7 4.8 | -9.9 14.2 230 15 8 7.1 3.9
18000 -8.2 17.2 195 22 11 8.7 4.8 | -8.3 17.1 225 12 6 7.5 4.1
17500 -7.0 19.4 200 21 11 8.6 4.7 | -7.1 19.2 215 11 5 8.2 4.5
17000 -5.8 21.6 200 19 10 8.6 4.7 | -6.0 21.2 205 9 5 8.2 4.5
16500 -4.5 23.9 200 18 9 9.1 5.0 | -4.8 23.4 190 9 5 8.5 4.6
16000 -3.2 26.2 205 16 8 9.2 5.0 | -3.6 25.5 180 8 4 8.5 4.6
15500 -1.8 28.8 205 15 8 9.2 5.0 | -2.3 27.9 170 8 4 8.2 4.5
15000 -0.5 31.1 200 13 6 9.1 5.0 | -1.1 30.0 160 9 4 8.1 4.4
14500 0.9 33.6 200 10 5 9.0 4.9 | 0.1 32.2 150 9 5 7.8 4.3
14000 2.2 36.0 190 8 4 8.1 4.4 | 1.2 34.2 140 10 5 7.1 3.9
13500 3.4 38.1 180 6 3 8.2 4.5 | 2.3 36.1 130 12 6 7.1 3.9
13000 4.6 40.3 140 4 2 7.0 3.8 | 3.5 38.3 120 13 7 8.3 4.6
12500 5.5 41.9 095 5 3 4.8 2.6 | 4.7 40.5 115 14 7 8.4 4.6
12000 6.4 43.5 075 7 4 7.0 3.9 | 5.8 42.4 105 15 8 6.6 3.6
11750 6.9 44.4 070 9 5 7.0 3.9 | 6.3 43.3 100 16 8 6.6 3.6
11500 7.4 45.3 065 10 5 6.6 3.6 | 6.8 44.2 095 16 8 8.1 4.4
11250 7.8 46.0 060 11 6 5.8 3.2 | 7.4 45.3 095 17 9 7.0 3.8
11000 8.3 46.9 055 12 6 5.3 2.9 | 7.8 46.0 090 17 9 4.7 2.6
10750 8.7 47.7 050 13 7 5.2 2.8 | 8.2 46.8 085 17 9 4.4 2.4
10500 9.1 48.4 045 14 7 5.5 3.0 | 8.6 47.5 075 17 9 6.3 3.5
10250 9.4 48.9 040 15 8 1.6 0.9 | 9.0 48.2 070 17 9 0.9 0.5
10000 9.3 48.7 035 16 8 -2.3 -1.2 | 8.6 47.5 060 16 8 -7.1 -3.9
9750 9.1 48.4 025 18 9 -2.4 -1.3 | 8.1 46.6 040 16 8 -5.8 -3.2
9500 8.9 48.0 020 20 10 -1.5 -0.8 | 7.5 45.5 025 16 8 -8.7 -4.8
9250 8.7 47.7 015 22 11 -4.8 -2.7 | 6.9 44.4 015 18 9 2.1 1.1
9000 8.2 46.8 015 22 12 -3.9 -2.1 | 7.7 45.9 010 18 9 11.1 6.1
8750 8.2 46.8 010 23 12 0.4 0.2 | 8.2 46.8 005 18 9 7.1 3.9
8500 8.1 46.6 360 23 12 4.3 2.4 | 8.8 47.8 360 18 9 8.2 4.5
8250 8.8 47.8 355 22 11 15.1 8.3 | 9.4 48.9 355 19 10 8.7 4.8
8000 10.2 50.4 355 19 10 19.8 10.9 | 10.3 50.5 355 18 9 18.1 9.9
7750 11.6 52.9 350 17 9 15.3 8.4 | 12.1 53.8 355 17 9 31.0 17.0
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
09/21/2024 at 1500 MDT | 09/21/2024 at 1800 MDT
|
CAPE... +3.3 LI... +0.3 | CAPE... +11.0 LI... -0.5
CINH... -0.1 K Index... +20.0 | CINH... 0.0 K Index... +19.2
|
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 -61.3 -78.3 220 49 25 2.7 1.5 | -59.8 -75.6 215 37 19 4.5 2.4
45000 -57.4 -71.3 220 79 41 2.4 1.3 | -54.1 -65.4 215 57 29 1.3 0.7
40000 -53.4 -64.1 210 94 48 4.9 2.7 | -52.0 -61.6 205 78 40 3.1 1.7
38000 -50.7 -59.3 205 82 42 4.6 2.5 | -49.8 -57.6 205 78 40 3.6 2.0
36000 -47.9 -54.2 200 71 37 4.7 2.6 | -47.7 -53.9 205 78 40 3.6 2.0
34000 -43.4 -46.1 195 65 34 8.7 4.8 | -44.3 -47.7 205 74 38 6.7 3.7
32000 -38.1 -36.6 195 61 32 8.8 4.8 | -40.3 -40.5 200 67 35 6.7 3.7
30000 -32.7 -26.9 200 57 29 9.2 5.0 | -35.3 -31.5 195 58 30 9.4 5.2
29000 -30.0 -22.0 200 55 28 9.2 5.1 | -32.5 -26.5 190 53 27 9.4 5.2
28000 -27.3 -17.1 205 53 27 9.4 5.2 | -29.7 -21.5 190 48 25 9.5 5.2
27000 -24.9 -12.8 205 49 25 7.3 4.0 | -27.3 -17.1 185 44 22 7.4 4.1
26000 -22.7 -8.9 205 45 23 7.3 4.0 | -25.1 -13.2 185 40 21 7.4 4.1
25000 -20.0 -4.0 210 40 21 7.4 4.1 | -22.9 -9.2 185 36 19 7.4 4.1
24000 -18.0 -0.4 205 36 19 6.5 3.6 | -21.0 -5.8 185 34 18 4.4 2.4
23000 -16.1 3.0 205 33 17 6.5 3.6 | -19.3 -2.7 195 36 18 4.6 2.5
22000 -14.2 6.4 200 29 15 6.8 3.7 | -17.9 -0.2 205 38 19 4.2 2.3
21000 -12.8 9.0 195 22 12 4.1 2.3 | -15.7 3.7 205 35 18 8.6 4.7
20000 -11.6 11.1 180 15 8 4.2 2.3 | -13.2 8.2 210 29 15 8.6 4.7
19500 -11.0 12.2 170 12 6 4.2 2.3 | -11.9 10.6 210 27 14 8.6 4.7
19000 -10.4 13.3 150 10 5 4.5 2.5 | -10.7 12.7 215 24 12 9.1 5.0
18500 -9.7 14.5 135 13 6 4.7 2.6 | -9.3 15.3 210 24 12 9.5 5.2
18000 -9.0 15.8 130 15 8 4.6 2.5 | -7.8 18.0 205 24 12 9.6 5.3
17500 -8.2 17.2 125 17 9 6.9 3.8 | -6.5 20.3 205 23 12 8.4 4.6
17000 -7.2 19.0 125 19 10 6.8 3.7 | -5.3 22.5 195 22 11 8.6 4.7
16500 -6.3 20.7 125 20 10 5.8 3.2 | -4.2 24.4 190 21 11 6.5 3.6
16000 -5.5 22.1 125 20 10 5.5 3.0 | -3.4 25.9 175 20 10 5.4 2.9
15500 -4.7 23.5 130 20 10 5.7 3.1 | -2.7 27.1 165 20 10 5.1 2.8
15000 -3.8 25.2 130 20 10 6.6 3.6 | -2.1 28.2 155 19 10 3.8 2.1
14500 -2.9 26.8 135 20 10 6.7 3.7 | -1.6 29.1 145 19 10 3.9 2.1
14000 -2.0 28.4 135 20 10 5.2 2.8 | -1.1 30.0 135 19 10 3.5 1.9
13500 -1.3 29.7 135 19 10 5.6 3.1 | -0.6 30.9 125 19 10 3.5 1.9
13000 -0.7 30.7 135 18 9 2.1 1.2 | -0.0 32.0 120 19 10 4.8 2.6
12500 -0.4 31.3 135 17 9 1.2 0.7 | 0.6 33.1 115 18 9 3.9 2.1
12000 -0.1 31.8 130 16 8 2.7 1.5 | 1.3 34.3 110 18 9 5.5 3.0
11750 0.1 32.2 125 15 8 2.5 1.4 | 1.7 35.1 105 17 9 6.1 3.3
11500 0.3 32.5 120 15 7 3.7 2.0 | 2.1 35.8 100 17 9 5.7 3.1
11250 0.6 33.1 120 14 7 5.6 3.1 | 2.5 36.5 095 17 9 5.0 2.7
11000 1.1 34.0 115 11 6 6.0 3.3 | 2.8 37.0 090 16 8 4.0 2.2
10750 1.5 34.7 105 9 4 6.0 3.3 | 3.1 37.6 085 16 8 3.3 1.8
10500 2.0 35.6 095 6 3 6.7 3.7 | 3.3 37.9 080 16 8 3.7 2.0
10250 2.6 36.7 060 4 2 11.0 6.1 | 3.6 38.5 075 16 8 3.5 1.9
10000 3.5 38.3 035 4 2 10.7 5.9 | 3.7 38.7 070 16 8 0.5 0.3
9750 4.1 39.4 025 4 2 8.1 4.4 | 3.7 38.7 055 16 8 -1.0 -0.6
9500 4.7 40.5 015 5 2 9.0 4.9 | 3.6 38.5 045 17 9 -1.3 -0.7
9250 5.4 41.7 005 5 3 7.9 4.4 | 3.6 38.5 035 18 9 1.3 0.7
9000 6.0 42.8 010 5 3 8.8 4.8 | 3.9 39.0 035 18 9 5.6 3.0
8750 6.7 44.1 010 5 3 10.2 5.6 | 4.3 39.7 035 17 9 6.3 3.5
8500 7.4 45.3 010 5 3 9.8 5.4 | 4.7 40.5 030 17 9 5.2 2.8
8250 8.2 46.8 015 5 3 10.5 5.8 | 5.1 41.2 025 17 9 9.2 5.0
8000 10.0 50.0 015 5 2 13.8 7.5 | 6.0 42.8 025 16 8 14.2 7.8
7750 11.0 51.8 015 5 2 11.4 6.3 | 7.0 44.6 025 13 7 10.7 5.9
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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