Soaring Guidance
Issued by NWS Pueblo, CO
Issued by NWS Pueblo, CO
596
UXUS97 KPUB 201205
SRGPUB
Soaring Forecast
National Weather Service Pueblo, Colorado
0605 MDT Monday, May 20, 2024
This forecast is for the Air Force Academy for Monday, May 20, 2024:
If the trigger temperature of 59.8 F/15.5 C is reached...then
Thermal Soaring Index....................... Excellent
Maximum rate of lift........................ 1363 ft/min (6.9 m/s)
Maximum height of thermals.................. 24067 ft MSL (16452 ft AGL)
Forecast maximum temperature................... 78.0 F/26.0 C
Time of trigger temperature.................... 0945 MDT
Time of overdevelopment........................ 2000 MDT
Middle/high clouds during soaring window....... Broken/overcast thin middle
Surface winds during soaring window............ 20 mph or less
Height of the -3 thermal index................. 20626 ft MSL (13012 ft AGL)
Thermal soaring outlook for Tuesday 05/21...... Excellent
Wave Soaring Index............................. Not available
Remarks...
Sunrise/Sunset.................... 05:41:47 / 20:09:58 MDT
Total possible sunshine........... 14 hr 28 min 11 sec (868 min 11 sec)
Altitude of sun at 12:55:53 MDT... 71.20 degrees
Upper air data from numerical model forecast valid on 05/20/2024 at 0600 MDT
Freezing level.................. 13234 ft MSL (5619 ft AGL)
Convective condensation level... 15281 ft MSL (7666 ft AGL)
Lifted condensation level....... 18370 ft MSL (10755 ft AGL)
Lifted index.................... -5.8
K index......................... +21.1
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 -56.5 -69.7 245 46 24 1.4 0.7 M M M M M
45000 -54.6 -66.3 255 63 33 0.4 0.2 M M M M M
40000 -54.1 -65.4 260 80 41 0.1 0.1 M M M M M
38000 -51.7 -61.1 260 79 40 4.4 2.4 M M M M M
36000 -49.1 -56.4 260 76 39 4.4 2.4 M M M M M
34000 -45.8 -50.4 260 70 36 6.7 3.6 M M M M M
32000 -41.8 -43.2 255 59 30 6.7 3.7 M M M M M
30000 -37.7 -35.9 250 50 26 7.2 4.0 31.2 88.1 4.4 M M
29000 -35.5 -31.9 245 46 24 7.2 4.0 30.2 86.3 3.6 M M
28000 -33.3 -27.9 240 43 22 7.2 4.0 29.3 84.7 3.0 M M
27000 -31.2 -24.2 240 41 21 7.2 3.9 28.4 83.1 2.3 M M
26000 -29.0 -20.2 240 41 21 7.2 3.9 27.3 81.2 1.5 M M
25000 -26.8 -16.2 245 41 21 7.2 3.9 26.4 79.6 0.7 M M
24000 -24.1 -11.4 245 41 21 7.7 4.2 25.4 77.7 -0.1 1544 7.8
23000 -21.8 -7.2 245 40 20 7.6 4.2 24.6 76.2 -0.8 1446 7.3
22000 -19.5 -3.1 245 39 20 7.6 4.2 23.9 75.0 -1.4 1348 6.8
21000 -17.6 0.3 245 36 18 5.1 2.8 22.7 72.8 -2.5 1262 6.4
20000 -16.2 2.8 245 30 16 5.0 2.8 21.0 69.8 -4.1 1189 6.0
19500 -15.5 4.1 245 28 14 5.1 2.8 20.2 68.4 -4.8 1152 5.9
19000 -14.7 5.5 245 25 13 5.5 3.0 19.5 67.0 -5.5 1115 5.7
18500 -13.8 7.2 250 23 12 7.6 4.2 19.0 66.2 -6.0 1071 5.4
18000 -12.7 9.1 250 22 11 7.5 4.1 18.6 65.5 -6.5 1025 5.2
17500 -11.5 11.3 255 21 11 9.5 5.2 18.4 65.0 -6.8 975 5.0
17000 -10.0 14.0 255 21 11 9.8 5.4 18.4 65.0 -6.9 916 4.7
16500 -8.6 16.5 255 20 10 9.8 5.4 18.4 65.1 -6.9 857 4.4
16000 -7.1 19.2 250 20 10 9.8 5.4 18.4 65.1 -6.9 798 4.1
15500 -5.6 21.9 250 20 10 9.9 5.4 18.4 65.1 -6.9 739 3.8
15000 -4.2 24.4 245 18 9 8.8 4.8 18.3 65.0 -7.1 683 3.5
14500 -2.9 26.8 240 17 9 9.0 4.9 18.2 64.7 -7.3 629 3.2
14000 -1.7 28.9 230 15 8 7.6 4.2 18.0 64.4 -7.5 577 2.9
13500 -0.6 30.9 215 14 7 7.6 4.2 17.6 63.7 -8.0 530 2.7
13000 0.5 32.9 200 14 7 8.6 4.7 17.3 63.2 -8.4 482 2.5
12500 1.6 34.9 195 15 8 6.7 3.7 17.0 62.6 -8.7 434 2.2
12000 2.6 36.7 190 15 8 7.0 3.8 16.5 61.8 -9.3 389 2.0
11750 3.1 37.6 185 15 8 7.0 3.8 16.3 61.4 -9.5 366 1.9
11500 3.6 38.5 185 14 7 7.4 4.1 16.1 61.0 -9.7 343 1.7
11250 4.2 39.6 180 14 7 7.9 4.3 16.0 60.7 -9.9 319 1.6
11000 4.7 40.5 180 15 7 7.6 4.1 15.8 60.5 -10.1 295 1.5
10750 5.3 41.5 175 14 7 7.4 4.1 15.6 60.1 -10.3 271 1.4
10500 5.8 42.4 170 13 7 7.3 4.0 15.4 59.8 -10.6 247 1.3
10250 6.4 43.5 165 12 6 7.4 4.0 15.3 59.5 -10.8 224 1.1
10000 6.9 44.4 155 12 6 5.2 2.9 15.0 59.0 -11.0 202 1.0
9750 7.1 44.8 150 10 5 3.5 1.9 14.6 58.2 -11.6 187 0.9
9500 7.4 45.3 140 9 4 3.9 2.2 14.1 57.4 -12.1 172 0.9
9250 7.6 45.7 125 7 4 4.2 2.3 13.7 56.6 -12.6 157 0.8
9000 7.9 46.2 110 6 3 2.7 1.5 13.2 55.8 -13.1 141 0.7
8750 8.0 46.4 075 4 2 1.0 0.5 12.6 54.7 -13.7 131 0.7
8500 8.1 46.6 030 5 2 2.2 1.2 12.0 53.5 -14.4 121 0.6
8250 8.2 46.8 005 8 4 -0.9 -0.5 11.3 52.4 -15.1 110 0.6
8000 7.9 46.2 355 9 5 -6.7 -3.7 10.3 50.5 -16.1 112 0.6
7750 7.3 45.1 355 9 4 -7.6 -4.2 9.0 48.2 -17.5 122 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 * * * * * *
05/20/2024 at 0900 MDT | 05/20/2024 at 1200 MDT
|
CAPE... +24.5 LI... +1.0 | CAPE... +340.9 LI... -0.8
CINH... -105.3 K Index... +11.6 | CINH... -13.5 K Index... -2.0
|
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 -56.9 -70.4 245 51 26 1.3 0.7 | -56.8 -70.2 245 51 27 1.0 0.6
45000 -55.2 -67.4 245 62 32 0.2 0.1 | -55.4 -67.7 245 65 33 0.2 0.1
40000 -54.9 -66.8 260 81 42 0.2 0.1 | -55.0 -67.0 255 89 46 0.4 0.2
38000 -52.1 -61.8 260 85 44 5.2 2.8 | -52.1 -61.8 255 93 48 5.3 2.9
36000 -49.0 -56.2 260 89 46 5.2 2.8 | -48.9 -56.0 255 97 50 5.3 2.9
34000 -45.5 -49.9 260 88 45 6.5 3.5 | -45.4 -49.7 255 95 49 6.5 3.6
32000 -41.6 -42.9 260 80 41 6.5 3.5 | -41.5 -42.7 255 89 46 6.5 3.6
30000 -37.6 -35.7 260 72 37 7.1 3.9 | -37.4 -35.3 255 81 42 7.0 3.9
29000 -35.5 -31.9 260 67 34 7.1 3.9 | -35.3 -31.5 255 76 39 7.0 3.9
28000 -33.4 -28.1 260 62 32 7.1 3.9 | -33.2 -27.8 255 71 36 7.0 3.9
27000 -31.3 -24.3 255 57 29 6.9 3.8 | -31.1 -24.0 255 65 34 6.5 3.6
26000 -29.2 -20.6 255 52 27 6.9 3.8 | -29.1 -20.4 255 59 31 6.5 3.6
25000 -27.1 -16.8 250 47 24 6.9 3.8 | -27.2 -17.0 250 54 28 6.5 3.6
24000 -25.0 -13.0 245 44 22 7.8 4.3 | -25.1 -13.2 250 48 25 8.8 4.9
23000 -22.1 -7.8 245 42 22 7.9 4.3 | -21.8 -7.2 250 42 22 9.0 4.9
22000 -19.7 -3.5 245 41 21 7.9 4.3 | -19.1 -2.4 245 38 20 9.0 4.9
21000 -17.3 0.9 245 40 20 8.0 4.4 | -16.6 2.1 245 38 19 7.7 4.3
20000 -14.9 5.2 245 38 20 8.0 4.4 | -14.2 6.4 245 40 21 7.7 4.2
19500 -13.7 7.3 245 38 19 7.9 4.3 | -13.1 8.4 245 42 21 7.7 4.2
19000 -12.5 9.5 245 37 19 7.3 4.0 | -11.9 10.6 245 43 22 7.6 4.2
18500 -11.7 10.9 240 35 18 4.8 2.6 | -10.8 12.6 245 43 22 7.4 4.0
18000 -11.0 12.2 240 32 16 5.2 2.8 | -9.7 14.5 245 42 22 7.3 4.0
17500 -10.3 13.5 235 29 15 5.9 3.2 | -8.5 16.7 245 41 21 8.0 4.4
17000 -9.5 14.9 230 25 13 6.2 3.4 | -7.3 18.9 245 39 20 8.1 4.5
16500 -8.6 16.5 225 21 11 7.5 4.1 | -6.1 21.0 245 38 20 7.6 4.2
16000 -7.2 19.0 225 20 10 9.8 5.4 | -5.1 22.8 240 37 19 6.5 3.6
15500 -5.8 21.6 230 20 10 9.8 5.4 | -4.1 24.6 240 36 19 6.7 3.7
15000 -4.3 24.3 230 19 10 9.5 5.2 | -3.3 26.1 240 34 18 5.3 2.9
14500 -2.9 26.8 225 19 10 9.6 5.3 | -2.5 27.5 235 32 16 5.5 3.0
14000 -1.4 29.5 225 19 10 9.5 5.2 | -1.6 29.1 230 29 15 8.6 4.7
13500 -0.0 32.0 225 19 10 9.5 5.2 | -0.3 31.5 225 27 14 8.9 4.9
13000 1.3 34.3 220 18 9 8.0 4.4 | 1.0 33.8 225 26 13 10.4 5.7
12500 2.3 36.1 215 18 9 6.1 3.3 | 2.4 36.3 220 24 12 8.4 4.6
12000 3.2 37.8 210 18 9 5.8 3.2 | 3.7 38.7 215 22 11 7.9 4.3
11750 3.5 38.3 205 18 9 5.4 3.0 | 4.2 39.6 215 22 11 7.1 3.9
11500 3.9 39.0 205 18 9 5.8 3.2 | 4.8 40.6 215 22 11 7.6 4.2
11250 4.3 39.7 200 18 9 5.9 3.3 | 5.3 41.5 210 21 11 8.6 4.7
11000 4.7 40.5 195 18 9 6.3 3.5 | 5.9 42.6 210 21 11 5.9 3.3
10750 5.2 41.4 195 17 9 6.7 3.7 | 6.1 43.0 205 19 10 2.8 1.5
10500 5.7 42.3 195 17 9 6.7 3.7 | 6.2 43.2 200 17 9 4.8 2.6
10250 6.2 43.2 195 16 8 7.8 4.3 | 6.7 44.1 195 16 8 9.8 5.4
10000 6.7 44.1 195 15 8 6.6 3.6 | 7.5 45.5 190 15 8 10.6 5.8
9750 7.1 44.8 195 14 7 5.2 2.9 | 8.2 46.8 185 15 8 8.7 4.8
9500 7.5 45.5 190 13 7 5.1 2.8 | 8.8 47.8 180 14 7 9.0 4.9
9250 7.9 46.2 185 12 6 7.2 4.0 | 9.5 49.1 175 14 7 9.5 5.2
9000 8.4 47.1 185 10 5 4.2 2.3 | 10.2 50.4 175 14 7 10.4 5.7
8750 8.4 47.1 195 6 3 -0.3 -0.2 | 11.0 51.8 175 14 7 10.6 5.8
8500 8.4 47.1 235 3 2 1.0 0.5 | 11.8 53.2 170 14 7 10.3 5.6
8250 8.4 47.1 300 4 2 0.5 0.3 | 12.5 54.5 170 14 7 11.4 6.2
8000 8.6 47.5 325 5 3 9.8 5.4 | 13.6 56.5 170 14 7 19.0 10.4
7750 9.9 49.8 335 6 3 24.8 13.6 | 15.4 59.7 165 12 6 28.2 15.5
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
05/20/2024 at 1500 MDT | 05/20/2024 at 1800 MDT
|
CAPE... +752.8 LI... -2.1 | CAPE... +978.5 LI... -5.5
CINH... -6.3 K Index... +6.7 | CINH... -14.1 K Index... +18.3
|
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 -56.7 -70.1 240 50 26 1.4 0.8 | -55.3 -67.5 240 48 25 2.4 1.3
45000 -54.8 -66.6 240 69 36 0.3 0.2 | -52.4 -62.3 240 67 35 -1.3 -0.7
40000 -54.3 -65.7 250 95 49 -0.1 -0.1 | -54.5 -66.1 240 92 47 -1.8 -1.0
38000 -51.9 -61.4 245 100 51 4.5 2.5 | -52.5 -62.5 240 98 50 4.2 2.3
36000 -49.2 -56.6 245 104 54 4.5 2.5 | -50.0 -58.0 240 104 53 4.2 2.3
34000 -45.9 -50.6 245 105 54 6.6 3.6 | -47.0 -52.6 245 104 53 6.0 3.3
32000 -41.9 -43.4 245 101 52 6.6 3.6 | -43.4 -46.1 245 97 50 6.0 3.3
30000 -37.8 -36.0 250 94 48 7.1 3.9 | -39.1 -38.4 240 86 44 8.8 4.8
29000 -35.7 -32.3 250 89 46 7.1 3.9 | -36.5 -33.7 235 78 40 8.8 4.8
28000 -33.6 -28.5 250 84 43 7.1 3.9 | -33.9 -29.0 235 71 37 8.8 4.8
27000 -31.5 -24.7 250 78 40 7.1 3.9 | -31.3 -24.3 230 66 34 8.2 4.5
26000 -29.3 -20.7 250 70 36 7.1 3.9 | -28.8 -19.8 235 67 35 8.3 4.6
25000 -27.2 -17.0 245 62 32 7.1 3.9 | -26.3 -15.3 235 69 35 8.3 4.6
24000 -25.1 -13.2 240 54 28 7.9 4.4 | -23.9 -11.0 240 70 36 6.0 3.3
23000 -22.0 -7.6 235 46 24 8.1 4.5 | -22.2 -8.0 245 65 34 4.7 2.6
22000 -19.6 -3.3 230 40 21 8.2 4.5 | -20.8 -5.4 250 62 32 4.7 2.6
21000 -17.1 1.2 230 37 19 8.6 4.7 | -19.1 -2.4 250 58 30 7.4 4.1
20000 -14.5 5.9 230 37 19 8.7 4.8 | -16.9 1.6 250 52 27 7.4 4.1
19500 -13.2 8.2 235 37 19 8.7 4.8 | -15.8 3.6 250 49 25 7.4 4.1
19000 -11.8 10.8 235 37 19 8.6 4.7 | -14.7 5.5 245 46 24 7.4 4.0
18500 -10.7 12.7 235 39 20 7.6 4.1 | -13.5 7.7 245 44 23 9.1 5.0
18000 -9.5 14.9 235 41 21 7.6 4.2 | -12.2 10.0 245 42 22 8.9 4.9
17500 -8.4 16.9 235 43 22 7.4 4.1 | -10.8 12.6 240 41 21 9.5 5.2
17000 -7.3 18.9 235 42 22 7.4 4.1 | -9.3 15.3 240 41 21 9.7 5.3
16500 -6.2 20.8 235 42 21 7.3 4.0 | -7.9 17.8 235 41 21 9.7 5.3
16000 -5.2 22.6 230 40 21 7.1 3.9 | -6.4 20.5 230 42 22 9.4 5.2
15500 -4.2 24.4 230 39 20 7.1 3.9 | -5.0 23.0 225 43 22 9.4 5.2
15000 -3.1 26.4 225 38 19 8.1 4.4 | -3.6 25.5 225 44 23 9.5 5.2
14500 -2.0 28.4 225 35 18 8.1 4.4 | -2.1 28.2 220 44 23 9.5 5.2
14000 -0.8 30.6 220 34 17 8.8 4.8 | -0.7 30.7 220 45 23 9.7 5.3
13500 0.5 32.9 220 32 16 9.0 4.9 | 0.7 33.3 215 44 23 9.9 5.5
13000 1.8 35.2 220 31 16 10.2 5.6 | 2.1 35.8 215 43 22 12.2 6.7
12500 3.1 37.6 215 29 15 7.1 3.9 | 3.5 38.3 210 42 22 6.0 3.3
12000 4.2 39.6 210 28 14 6.1 3.3 | 4.4 39.9 210 41 21 7.5 4.1
11750 4.5 40.1 210 27 14 4.4 2.4 | 5.0 41.0 205 40 21 8.4 4.6
11500 4.8 40.6 205 26 13 6.7 3.7 | 5.5 41.9 205 40 20 7.7 4.2
11250 5.3 41.5 200 25 13 7.8 4.3 | 6.0 42.8 200 39 20 7.2 4.0
11000 5.8 42.4 200 24 12 7.4 4.1 | 6.5 43.7 200 38 20 7.4 4.0
10750 6.3 43.3 190 23 12 7.0 3.8 | 7.0 44.6 195 37 19 7.0 3.8
10500 6.8 44.2 185 22 12 7.8 4.3 | 7.4 45.3 195 36 19 7.7 4.2
10250 7.4 45.3 180 22 11 10.6 5.8 | 8.0 46.4 190 36 18 9.7 5.3
10000 8.3 46.9 180 22 11 10.6 5.8 | 8.8 47.8 190 35 18 9.6 5.3
9750 9.0 48.2 175 22 11 9.3 5.1 | 9.4 48.9 185 34 18 8.0 4.4
9500 9.7 49.5 175 22 11 8.8 4.9 | 9.9 49.8 185 34 17 7.2 4.0
9250 10.4 50.7 175 22 11 10.8 5.9 | 10.5 50.9 185 33 17 8.6 4.7
9000 11.2 52.2 175 22 11 11.8 6.5 | 11.1 52.0 180 32 16 10.0 5.5
8750 12.1 53.8 175 22 11 10.4 5.7 | 11.9 53.4 180 30 16 9.6 5.2
8500 12.8 55.0 175 22 11 10.9 6.0 | 12.6 54.7 180 29 15 9.7 5.3
8250 13.6 56.5 175 22 11 9.5 5.2 | 13.3 55.9 180 28 14 9.2 5.0
8000 14.5 58.1 170 21 11 16.6 9.1 | 14.0 57.2 180 27 14 10.9 6.0
7750 16.3 61.3 170 19 10 32.5 17.8 | 15.9 60.6 175 18 9 8.3 4.5
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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