Soaring Guidance
Issued by NWS Pueblo, CO
Issued by NWS Pueblo, CO
566
UXUS97 KPUB 181204
SRGPUB
Soaring Forecast
National Weather Service Pueblo, Colorado
0604 MDT Tuesday, June 18, 2024
This forecast is for the Air Force Academy for Tuesday, June 18, 2024:
If the trigger temperature of 71.0 F/21.7 C is reached...then
Thermal Soaring Index....................... Excellent
Maximum rate of lift........................ 1045 ft/min (5.3 m/s)
Maximum height of thermals.................. 18354 ft MSL (10767 ft AGL)
Forecast maximum temperature................... 78.0 F/26.0 C
Time of trigger temperature.................... 1045 MDT
Time of overdevelopment........................ 1900 MDT
Middle/high clouds during soaring window....... None
Surface winds during soaring window............ 20 mph or less
Height of the -3 thermal index................. 12499 ft MSL (4912 ft AGL)
Thermal soaring outlook for Wednesday 06/19.... Poor
Wave Soaring Index............................. Not available
Remarks...
Sunrise/Sunset.................... 05:33:31 / 20:27:43 MDT
Total possible sunshine........... 14 hr 54 min 12 sec (894 min 12 sec)
Altitude of sun at 13:00:37 MDT... 74.44 degrees
Upper air data from numerical model forecast valid on 06/18/2024 at 0600 MDT
Freezing level.................. 15561 ft MSL (7974 ft AGL)
Convective condensation level... 21604 ft MSL (14017 ft AGL)
Lifted condensation level....... 20356 ft MSL (12768 ft AGL)
Lifted index.................... +1.8
K index......................... +11.2
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 -57.0 -70.6 235 53 28 4.0 2.2 M M M M M
45000 -52.7 -62.9 230 67 34 -1.6 -0.9 M M M M M
40000 -54.8 -66.6 225 58 30 3.9 2.1 M M M M M
38000 -51.1 -60.0 220 56 29 6.2 3.4 M M M M M
36000 -47.4 -53.3 220 55 28 6.2 3.4 M M M M M
34000 -43.1 -45.6 215 53 27 7.7 4.2 M M M M M
32000 -37.9 -36.2 210 52 27 7.8 4.3 M M M M M
30000 -32.8 -27.0 215 51 26 8.8 4.8 35.3 95.6 7.6 M M
29000 -30.2 -22.4 215 51 26 8.8 4.8 35.0 95.0 7.4 M M
28000 -27.6 -17.7 220 50 26 9.0 4.9 34.8 94.6 7.2 M M
27000 -25.2 -13.4 220 50 26 7.5 4.1 34.0 93.2 6.7 M M
26000 -23.0 -9.4 220 49 25 7.5 4.1 33.2 91.7 6.1 M M
25000 -20.8 -5.4 225 49 25 7.5 4.1 32.4 90.4 5.5 M M
24000 -18.5 -1.3 225 48 25 7.5 4.1 31.6 88.9 4.9 M M
23000 -16.3 2.7 225 47 24 7.5 4.1 30.8 87.4 4.2 M M
22000 -14.1 6.6 225 45 23 7.4 4.1 30.0 86.0 3.6 M M
21000 -12.0 10.4 225 43 22 6.5 3.6 29.1 84.3 2.8 M M
20000 -10.0 14.0 220 39 20 6.5 3.6 27.9 82.2 1.9 M M
19500 -9.0 15.8 220 37 19 6.5 3.6 27.4 81.3 1.4 M M
19000 -7.6 18.3 215 34 17 5.9 3.2 26.6 79.9 0.8 M M
18500 -6.8 19.8 205 29 15 5.4 3.0 25.9 78.6 0.1 M M
18000 -6.1 21.0 200 25 13 5.1 2.8 25.1 77.3 -0.7 1011 5.1
17500 -5.0 23.0 190 22 11 9.3 5.1 24.7 76.5 -1.1 966 4.9
17000 -3.8 25.2 190 19 10 8.9 4.9 24.6 76.2 -1.3 912 4.6
16500 -2.5 27.5 190 17 9 9.2 5.0 24.5 76.0 -1.4 858 4.4
16000 -1.1 30.0 190 15 8 9.4 5.1 24.4 75.9 -1.5 802 4.1
15500 0.3 32.5 195 14 7 9.3 5.1 24.3 75.8 -1.6 745 3.8
15000 1.6 34.9 205 13 7 8.6 4.7 24.2 75.5 -1.7 691 3.5
14500 2.9 37.2 220 13 7 8.8 4.8 24.0 75.2 -1.9 638 3.2
14000 4.2 39.6 240 14 7 7.6 4.2 23.8 74.8 -2.2 586 3.0
13500 5.3 41.5 255 16 8 7.2 4.0 23.4 74.2 -2.5 537 2.7
13000 6.6 43.9 265 18 9 10.0 5.5 23.3 73.9 -2.6 483 2.5
12500 7.7 45.9 270 20 10 6.2 3.4 22.9 73.3 -3.0 435 2.2
12000 8.7 47.7 280 23 12 7.1 3.9 22.4 72.3 -3.5 392 2.0
11750 9.3 48.7 280 22 11 8.5 4.6 22.3 72.1 -3.7 367 1.9
11500 9.9 49.8 280 21 11 8.7 4.8 22.2 71.9 -3.8 340 1.7
11250 10.6 51.1 280 20 10 9.2 5.1 22.1 71.8 -3.8 313 1.6
11000 11.2 52.2 285 19 10 8.2 4.5 22.1 71.7 -3.9 285 1.4
10750 11.8 53.2 290 17 9 6.7 3.7 21.9 71.4 -4.1 262 1.3
10500 12.3 54.1 295 16 8 7.4 4.0 21.6 71.0 -4.3 239 1.2
10250 12.9 55.2 300 15 8 9.1 5.0 21.5 70.8 -4.5 214 1.1
10000 13.5 56.3 305 14 7 7.3 4.0 21.5 70.6 -4.6 187 0.9
9750 13.9 57.0 315 14 7 4.6 2.5 21.1 70.0 -4.9 167 0.9
9500 14.3 57.7 325 14 7 4.3 2.4 20.7 69.3 -5.3 150 0.8
9250 14.6 58.3 330 15 8 5.2 2.8 20.3 68.6 -5.7 133 0.7
9000 15.0 59.0 335 16 8 4.6 2.5 20.0 68.0 -6.1 114 0.6
8750 15.3 59.5 340 16 8 3.7 2.1 19.5 67.2 -6.6 98 0.5
8500 15.5 59.9 345 17 9 2.0 1.1 19.1 66.3 -7.1 83 0.4
8250 15.8 60.4 345 18 9 8.8 4.8 18.6 65.5 -7.6 69 0.3
8000 16.3 61.3 350 19 10 -2.6 -1.4 18.5 65.2 -7.7 44 0.2
7750 14.7 58.5 350 14 7 -41.3 -22.7 16.0 60.9 -10.1 86 0.4
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 * * * * * *
06/18/2024 at 0900 MDT | 06/18/2024 at 1200 MDT
|
CAPE... 0.0 LI... +3.2 | CAPE... +1.0 LI... +2.0
CINH... 0.0 K Index... -1.8 | CINH... -0.2 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 -58.5 -73.3 225 52 27 3.6 2.0 | -58.4 -73.1 220 52 27 2.9 1.6
45000 -54.4 -65.9 225 65 34 -0.7 -0.4 | -54.7 -66.5 225 73 38 0.7 0.4
40000 -55.2 -67.4 225 66 34 6.6 3.6 | -53.6 -64.5 230 73 38 4.2 2.3
38000 -51.1 -60.0 225 64 33 6.8 3.7 | -50.2 -58.4 225 72 37 5.6 3.1
36000 -47.0 -52.6 220 61 32 6.8 3.7 | -46.8 -52.2 225 70 36 5.6 3.1
34000 -42.6 -44.7 220 59 31 7.5 4.1 | -42.8 -45.0 220 69 36 7.5 4.1
32000 -38.1 -36.6 220 58 30 7.5 4.1 | -37.8 -36.0 220 68 35 7.5 4.1
30000 -33.3 -27.9 220 56 29 8.3 4.6 | -33.2 -27.8 225 65 33 7.6 4.2
29000 -30.8 -23.4 220 56 29 8.3 4.6 | -31.0 -23.8 225 63 32 7.6 4.2
28000 -28.3 -18.9 220 56 29 8.3 4.6 | -28.7 -19.7 225 61 31 7.6 4.2
27000 -25.9 -14.6 220 55 28 8.1 4.5 | -26.4 -15.5 225 59 30 7.8 4.3
26000 -23.4 -10.1 220 53 27 8.1 4.5 | -24.0 -11.2 225 56 29 7.8 4.3
25000 -21.0 -5.8 225 52 27 8.1 4.4 | -21.7 -7.1 225 54 28 7.8 4.3
24000 -18.8 -1.8 225 50 26 6.3 3.5 | -19.3 -2.7 230 52 27 7.9 4.4
23000 -16.4 2.5 230 46 24 6.5 3.5 | -16.9 1.6 230 50 26 7.9 4.4
22000 -14.4 6.1 230 44 22 6.4 3.5 | -14.5 5.9 235 48 25 7.9 4.3
21000 -12.3 9.9 230 43 22 7.6 4.2 | -12.3 9.9 235 46 24 6.7 3.7
20000 -10.0 14.0 230 43 22 7.6 4.2 | -10.4 13.3 235 44 23 6.7 3.7
19500 -8.9 16.0 230 42 22 7.6 4.2 | -8.9 16.0 240 43 22 6.7 3.7
19000 -7.7 18.1 230 42 22 7.6 4.2 | -7.9 17.8 240 42 22 5.9 3.2
18500 -6.5 20.3 230 42 21 7.8 4.3 | -7.1 19.2 240 42 21 5.5 3.0
18000 -5.3 22.5 230 41 21 8.2 4.5 | -6.4 20.5 240 41 21 5.5 3.0
17500 -4.2 24.4 225 40 20 6.0 3.3 | -5.5 22.1 240 40 21 6.6 3.6
17000 -3.3 26.1 225 38 19 6.2 3.4 | -4.6 23.7 240 40 20 6.5 3.6
16500 -2.4 27.7 220 36 19 6.2 3.4 | -3.6 25.5 240 39 20 6.0 3.3
16000 -1.5 29.3 220 34 17 6.3 3.5 | -2.9 26.8 240 36 19 5.8 3.2
15500 -0.6 30.9 220 31 16 6.4 3.5 | -2.1 28.2 240 34 17 6.3 3.5
15000 0.4 32.7 220 29 15 8.3 4.6 | -0.9 30.4 240 31 16 9.3 5.1
14500 1.6 34.9 220 28 14 8.2 4.5 | 0.4 32.7 240 27 14 9.1 5.0
14000 2.9 37.2 220 26 13 8.6 4.7 | 1.7 35.1 240 24 13 8.9 4.9
13500 4.2 39.6 220 23 12 8.5 4.7 | 3.0 37.4 235 23 12 8.8 4.8
13000 5.5 41.9 225 21 11 9.5 5.2 | 4.3 39.7 235 21 11 8.6 4.7
12500 6.5 43.7 235 21 11 4.5 2.5 | 5.3 41.5 235 19 10 5.8 3.2
12000 7.2 45.0 250 24 12 6.0 3.3 | 6.1 43.0 230 16 8 3.0 1.6
11750 7.8 46.0 255 23 12 7.5 4.1 | 6.1 43.0 225 15 8 1.7 0.9
11500 8.3 46.9 255 22 12 7.6 4.2 | 6.4 43.5 225 14 7 5.1 2.8
11250 8.9 48.0 255 21 11 8.8 4.9 | 6.8 44.2 220 13 7 6.2 3.4
11000 9.5 49.1 255 20 10 6.0 3.3 | 7.2 45.0 210 12 6 5.3 2.9
10750 9.8 49.6 255 17 9 2.9 1.6 | 7.6 45.7 200 10 5 4.2 2.3
10500 10.0 50.0 255 14 7 3.3 1.8 | 7.9 46.2 185 8 4 6.3 3.5
10250 10.2 50.4 255 11 5 5.0 2.7 | 8.6 47.5 170 8 4 11.1 6.1
10000 10.5 50.9 250 8 4 2.1 1.1 | 9.4 48.9 155 8 4 10.7 5.9
9750 10.4 50.7 250 6 3 -1.8 -1.0 | 10.1 50.2 145 8 4 8.9 4.9
9500 10.3 50.5 260 3 2 -2.3 -1.3 | 10.8 51.4 140 9 5 9.0 4.9
9250 10.1 50.2 290 1 1 0.9 0.5 | 11.5 52.7 130 9 5 10.2 5.6
9000 10.3 50.5 045 2 1 4.4 2.4 | 12.3 54.1 130 10 5 11.0 6.0
8750 10.6 51.1 025 3 1 3.6 2.0 | 13.1 55.6 130 10 5 10.3 5.6
8500 10.9 51.6 015 4 2 3.5 1.9 | 13.9 57.0 125 10 5 10.0 5.5
8250 11.1 52.0 010 5 2 4.4 2.4 | 14.6 58.3 125 10 5 11.8 6.5
8000 11.7 53.1 010 6 3 13.3 7.3 | 15.8 60.4 125 10 5 20.0 11.0
7750 13.1 55.6 015 6 3 25.1 13.8 | 17.6 63.7 120 10 5 28.1 15.4
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
06/18/2024 at 1500 MDT | 06/18/2024 at 1800 MDT
|
CAPE... +18.0 LI... +0.1 | CAPE... +61.9 LI... -1.1
CINH... -2.3 K Index... +23.0 | CINH... -126.7 K Index... +23.2
|
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 -58.2 -72.8 225 54 28 1.7 0.9 | -57.7 -71.9 225 55 28 1.7 0.9
45000 -55.7 -68.3 225 72 37 1.4 0.8 | -55.5 -67.9 230 73 37 0.7 0.4
40000 -53.3 -63.9 230 68 35 5.4 3.0 | -54.2 -65.6 230 71 37 4.7 2.6
38000 -49.9 -57.8 230 67 35 5.7 3.1 | -50.5 -58.9 235 70 36 6.1 3.4
36000 -46.4 -51.5 230 66 34 5.7 3.1 | -46.9 -52.4 235 69 36 6.1 3.4
34000 -42.4 -44.3 230 65 34 7.3 4.0 | -42.4 -44.3 235 66 34 7.0 3.9
32000 -38.0 -36.4 230 64 33 7.3 4.0 | -38.1 -36.6 240 62 32 7.0 3.9
30000 -33.7 -28.7 230 63 32 7.2 3.9 | -33.9 -29.0 240 60 31 7.2 4.0
29000 -31.5 -24.7 235 62 32 7.2 3.9 | -31.7 -25.1 240 59 30 7.2 4.0
28000 -29.4 -20.9 235 62 32 7.1 3.9 | -29.6 -21.3 240 58 30 7.2 4.0
27000 -27.1 -16.8 235 61 31 7.9 4.3 | -27.3 -17.1 240 57 30 7.5 4.1
26000 -24.7 -12.5 235 59 30 7.9 4.3 | -25.1 -13.2 240 57 29 7.5 4.1
25000 -21.8 -7.2 235 57 30 7.9 4.3 | -22.9 -9.2 240 57 29 7.5 4.1
24000 -19.4 -2.9 235 56 29 8.1 4.5 | -20.7 -5.3 240 55 28 7.5 4.1
23000 -16.9 1.6 240 55 29 8.1 4.5 | -18.5 -1.3 235 51 26 7.5 4.1
22000 -14.5 5.9 240 54 28 8.4 4.6 | -16.3 2.7 235 47 24 7.6 4.2
21000 -12.7 9.1 240 52 27 5.4 3.0 | -13.7 7.3 230 43 22 6.7 3.7
20000 -11.1 12.0 245 48 25 5.5 3.0 | -11.8 10.8 225 40 21 6.7 3.7
19500 -10.3 13.5 245 46 24 5.6 3.0 | -10.8 12.6 220 39 20 6.7 3.7
19000 -9.5 14.9 245 45 23 5.8 3.2 | -9.8 14.4 220 38 20 9.0 5.0
18500 -8.7 16.3 245 40 20 6.0 3.3 | -8.4 16.9 220 37 19 9.6 5.2
18000 -7.9 17.8 245 35 18 5.9 3.3 | -6.9 19.6 220 36 19 9.6 5.2
17500 -6.9 19.6 245 31 16 8.5 4.7 | -5.6 21.9 220 35 18 9.2 5.0
17000 -5.7 21.7 245 29 15 8.3 4.6 | -4.2 24.4 215 33 17 9.2 5.1
16500 -4.5 23.9 240 28 14 8.7 4.7 | -2.9 26.8 215 32 16 8.8 4.8
16000 -3.2 26.2 240 27 14 8.9 4.9 | -1.6 29.1 215 30 15 8.7 4.8
15500 -1.9 28.6 240 25 13 8.9 4.9 | -0.4 31.3 215 28 15 8.5 4.7
15000 -0.6 30.9 240 24 13 8.6 4.7 | 0.8 33.4 215 27 14 8.1 4.5
14500 0.7 33.3 240 23 12 8.7 4.8 | 2.0 35.6 210 25 13 8.1 4.5
14000 1.9 35.4 235 22 11 7.9 4.3 | 2.9 37.2 210 22 12 5.4 3.0
13500 3.1 37.6 230 20 11 7.8 4.3 | 3.7 38.7 200 19 10 5.7 3.1
13000 4.3 39.7 225 19 10 7.7 4.2 | 4.5 40.1 195 15 8 4.6 2.5
12500 5.0 41.0 210 16 8 3.4 1.8 | 5.1 41.2 175 11 6 3.8 2.1
12000 5.5 41.9 190 14 7 1.7 0.9 | 5.6 42.1 145 10 5 3.4 1.9
11750 5.6 42.1 175 13 6 1.2 0.6 | 5.8 42.4 135 10 5 4.3 2.3
11500 5.8 42.4 165 12 6 5.4 2.9 | 6.2 43.2 130 10 5 7.0 3.9
11250 6.3 43.3 155 13 7 7.0 3.8 | 6.8 44.2 125 10 5 8.3 4.6
11000 6.8 44.2 150 14 7 8.3 4.5 | 7.4 45.3 120 10 5 8.8 4.8
10750 7.5 45.5 150 14 7 9.9 5.4 | 8.1 46.6 120 10 5 9.1 5.0
10500 8.2 46.8 150 14 7 9.8 5.3 | 8.8 47.8 120 10 5 9.4 5.2
10250 9.0 48.2 145 14 7 10.9 6.0 | 9.5 49.1 120 10 5 10.3 5.7
10000 9.8 49.6 145 14 7 10.4 5.7 | 10.3 50.5 120 11 5 10.0 5.5
9750 10.6 51.1 145 14 7 9.8 5.4 | 11.0 51.8 120 11 5 9.8 5.3
9500 11.3 52.3 145 14 7 9.8 5.4 | 11.7 53.1 120 11 5 9.3 5.1
9250 12.0 53.6 145 15 7 10.3 5.6 | 12.5 54.5 120 11 5 11.3 6.2
9000 12.8 55.0 145 15 8 10.5 5.8 | 13.4 56.1 115 11 5 11.2 6.2
8750 13.6 56.5 145 15 8 10.4 5.7 | 14.1 57.4 115 11 5 9.4 5.2
8500 14.4 57.9 145 15 8 9.9 5.4 | 14.8 58.6 115 11 5 9.4 5.1
8250 15.1 59.2 140 15 8 12.0 6.6 | 15.5 59.9 115 11 5 11.5 6.3
8000 16.3 61.3 140 14 7 20.5 11.3 | 16.6 61.9 115 10 5 16.3 8.9
7750 20.0 68.0 135 13 7 16.8 9.2 | 19.1 66.4 110 10 5 17.5 9.6
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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