Soaring Guidance
Issued by NWS Pueblo, CO
Issued by NWS Pueblo, CO
234
UXUS97 KPUB 291212
SRGPUB
Soaring Forecast
National Weather Service Pueblo, Colorado
0612 MDT Wednesday, May 29, 2024
This forecast is for the Air Force Academy for Wednesday, May 29, 2024:
If the trigger temperature of 67.2 F/19.6 C is reached...then
Thermal Soaring Index....................... Excellent
Maximum rate of lift........................ 1548 ft/min (7.9 m/s)
Maximum height of thermals.................. 22792 ft MSL (15175 ft AGL)
Forecast maximum temperature................... 76.0 F/24.9 C
Time of trigger temperature.................... 1030 MDT
Time of overdevelopment........................ 1600 MDT
Middle/high clouds during soaring window....... None
Surface winds during soaring window............ 20 mph or less
Height of the -3 thermal index................. 16795 ft MSL (9178 ft AGL)
Thermal soaring outlook for Thursday 05/30..... Excellent
Wave Soaring Index............................. Not available
Remarks...
Sunrise/Sunset.................... 05:36:27 / 20:17:11 MDT
Total possible sunshine........... 14 hr 40 min 43 sec (880 min 43 sec)
Altitude of sun at 12:56:49 MDT... 72.79 degrees
Upper air data from numerical model forecast valid on 05/29/2024 at 0600 MDT
Freezing level.................. 14600 ft MSL (6983 ft AGL)
Convective condensation level... 15645 ft MSL (8028 ft AGL)
Lifted condensation level....... 17084 ft MSL (9467 ft AGL)
Lifted index.................... -6.5
K index......................... +20.0
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 -56.4 -69.5 270 31 16 1.0 0.6 M M M M M
45000 -55.5 -67.9 260 39 20 -2.2 -1.2 M M M M M
40000 -59.0 -74.2 265 47 24 0.1 0.1 M M M M M
38000 -55.6 -68.1 265 45 23 6.1 3.3 M M M M M
36000 -51.9 -61.4 265 42 22 6.1 3.3 M M M M M
34000 -47.7 -53.9 265 38 20 7.7 4.2 M M M M M
32000 -43.0 -45.4 265 33 17 7.7 4.2 M M M M M
30000 -38.4 -37.1 265 28 14 7.8 4.3 29.9 85.7 4.2 M M
29000 -36.0 -32.8 265 25 13 7.8 4.3 29.1 84.4 3.7 M M
28000 -33.7 -28.7 265 23 12 7.8 4.3 28.5 83.3 3.2 M M
27000 -31.3 -24.3 265 21 11 7.9 4.4 27.8 82.0 2.7 M M
26000 -28.9 -20.0 265 21 11 7.9 4.4 27.0 80.7 2.1 M M
25000 -25.9 -14.6 265 20 10 8.0 4.4 26.3 79.4 1.5 M M
24000 -23.7 -10.7 270 20 10 7.3 4.0 25.5 77.8 0.8 M M
23000 -21.5 -6.7 270 20 10 7.3 4.0 24.6 76.2 0.1 M M
22000 -19.3 -2.7 275 20 10 7.3 4.0 23.8 74.8 -0.6 1464 7.4
21000 -17.1 1.2 270 20 11 7.5 4.1 22.9 73.2 -1.4 1368 6.9
20000 -14.9 5.2 270 21 11 7.7 4.2 22.2 71.9 -2.1 1272 6.5
19500 -13.8 7.2 270 22 11 7.6 4.2 21.8 71.3 -2.5 1224 6.2
19000 -12.6 9.3 265 22 11 9.6 5.3 21.6 71.0 -2.7 1173 6.0
18500 -11.1 12.0 270 21 11 9.7 5.3 21.6 70.9 -2.8 1115 5.7
18000 -9.6 14.7 270 21 11 9.6 5.3 21.6 70.9 -2.8 1056 5.4
17500 -8.3 17.1 270 20 10 9.3 5.1 21.6 70.8 -2.9 999 5.1
17000 -6.9 19.6 270 19 10 9.2 5.1 21.5 70.7 -3.0 943 4.8
16500 -5.5 22.1 270 18 9 9.6 5.3 21.4 70.6 -3.0 886 4.5
16000 -4.1 24.6 270 17 9 9.6 5.3 21.4 70.5 -3.1 829 4.2
15500 -2.6 27.3 270 16 8 9.6 5.3 21.4 70.5 -3.2 772 3.9
15000 -1.2 29.8 265 16 8 9.6 5.3 21.3 70.4 -3.2 714 3.6
14500 0.2 32.4 265 15 8 9.5 5.2 21.3 70.4 -3.3 656 3.3
14000 1.6 34.9 260 14 7 9.3 5.1 21.3 70.3 -3.4 601 3.1
13500 2.9 37.2 255 13 7 9.3 5.1 21.2 70.2 -3.5 545 2.8
13000 4.2 39.6 245 13 6 8.2 4.5 21.0 69.9 -3.8 493 2.5
12500 5.4 41.7 235 13 7 8.9 4.9 20.9 69.5 -4.0 442 2.2
12000 6.6 43.9 225 13 7 7.7 4.2 20.6 69.1 -4.3 392 2.0
11750 7.2 45.0 220 14 7 8.0 4.4 20.5 68.8 -4.5 367 1.9
11500 7.7 45.9 215 14 7 6.0 3.3 20.3 68.5 -4.7 343 1.7
11250 8.1 46.6 210 15 8 5.4 3.0 19.9 67.9 -5.1 325 1.7
11000 8.5 47.3 210 15 8 6.6 3.6 19.6 67.4 -5.4 304 1.5
10750 9.0 48.2 205 15 8 6.5 3.6 19.4 66.9 -5.7 283 1.4
10500 9.4 48.9 205 16 8 5.8 3.2 19.1 66.4 -6.0 262 1.3
10250 9.8 49.6 200 17 9 5.1 2.8 18.8 65.8 -6.3 243 1.2
10000 10.2 50.4 200 17 8 5.7 3.1 18.5 65.2 -6.7 224 1.1
9750 10.6 51.1 200 16 8 5.5 3.0 18.1 64.6 -7.1 205 1.0
9500 11.0 51.8 200 16 8 6.1 3.3 17.8 64.1 -7.4 186 0.9
9250 11.3 52.3 200 16 8 2.3 1.3 17.5 63.4 -7.8 169 0.9
9000 11.2 52.2 200 15 8 -0.2 -0.1 16.7 62.1 -8.7 163 0.8
8750 11.2 52.2 205 13 7 1.4 0.8 16.0 60.9 -9.4 156 0.8
8500 11.2 52.2 205 12 6 0.5 0.3 15.4 59.7 -10.2 149 0.8
8250 11.1 52.0 210 11 5 -3.6 -2.0 14.6 58.2 -11.1 146 0.7
8000 10.5 50.9 210 10 5 -12.0 -6.6 13.3 55.9 -12.5 157 0.8
7750 9.3 48.7 210 7 4 -18.5 -10.1 11.3 52.4 -14.4 185 0.9
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 * * * * * *
05/29/2024 at 0900 MDT | 05/29/2024 at 1200 MDT
|
CAPE... +1202.8 LI... -4.0 | CAPE... +1254.8 LI... -4.7
CINH... -81.9 K Index... +18.3 | CINH... -8.1 K Index... +17.9
|
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 -55.7 -68.3 270 28 15 0.8 0.4 | -55.3 -67.5 260 24 12 0.3 0.2
45000 -55.3 -67.5 265 38 20 -2.7 -1.5 | -55.6 -68.1 270 33 17 -2.6 -1.4
40000 -59.3 -74.7 260 52 27 -1.9 -1.0 | -59.4 -74.9 255 52 27 -2.1 -1.2
38000 -55.9 -68.6 265 50 26 6.4 3.5 | -56.1 -69.0 255 49 25 6.3 3.4
36000 -52.1 -61.8 265 48 25 6.4 3.5 | -52.4 -62.3 255 46 23 6.3 3.4
34000 -47.1 -52.8 265 44 23 8.0 4.4 | -47.1 -52.8 260 42 22 8.9 4.9
32000 -42.3 -44.1 260 40 21 8.0 4.4 | -41.8 -43.2 260 40 21 8.9 4.9
30000 -37.6 -35.7 260 34 17 7.7 4.2 | -37.2 -35.0 265 36 18 7.1 3.9
29000 -35.3 -31.5 265 30 16 7.7 4.2 | -35.1 -31.2 265 33 17 7.1 3.9
28000 -33.0 -27.4 265 27 14 7.8 4.3 | -32.9 -27.2 265 30 15 7.0 3.9
27000 -30.8 -23.4 265 24 12 7.4 4.1 | -30.8 -23.4 265 26 13 7.4 4.0
26000 -28.5 -19.3 265 22 11 7.5 4.1 | -28.6 -19.5 260 22 12 7.4 4.0
25000 -26.3 -15.3 270 20 10 7.5 4.1 | -26.3 -15.3 250 19 10 7.4 4.0
24000 -24.0 -11.2 270 19 10 7.6 4.2 | -24.1 -11.4 245 17 9 7.5 4.1
23000 -21.8 -7.2 270 17 9 7.6 4.2 | -21.9 -7.4 245 15 8 7.5 4.1
22000 -19.5 -3.1 270 15 8 7.6 4.2 | -19.6 -3.3 245 13 7 7.5 4.1
21000 -17.3 0.9 270 16 8 7.2 4.0 | -17.4 0.7 245 14 7 7.6 4.1
20000 -14.7 5.5 265 17 9 7.4 4.1 | -14.6 5.7 250 16 8 7.8 4.3
19500 -13.6 7.5 260 18 9 7.4 4.1 | -13.5 7.7 250 17 9 7.7 4.2
19000 -12.4 9.7 260 18 9 9.7 5.3 | -12.3 9.9 250 18 9 9.8 5.4
18500 -11.0 12.2 260 18 9 9.6 5.3 | -10.8 12.6 250 18 9 9.7 5.3
18000 -9.5 14.9 260 18 9 9.6 5.3 | -9.4 15.1 250 17 9 9.6 5.3
17500 -8.1 17.4 260 17 9 9.6 5.3 | -8.0 17.6 250 17 9 9.5 5.2
17000 -6.7 19.9 260 16 8 9.6 5.3 | -6.6 20.1 250 17 9 9.5 5.2
16500 -5.3 22.5 265 16 8 9.6 5.3 | -5.2 22.6 250 16 8 9.6 5.3
16000 -3.8 25.2 260 15 8 9.6 5.3 | -3.7 25.3 250 16 8 9.6 5.3
15500 -2.4 27.7 260 14 7 9.6 5.2 | -2.3 27.9 250 15 8 9.6 5.3
15000 -1.0 30.2 260 14 7 9.6 5.2 | -0.9 30.4 250 14 7 9.6 5.3
14500 0.4 32.7 260 13 7 9.6 5.3 | 0.5 32.9 250 14 7 9.6 5.3
14000 1.8 35.2 255 13 6 9.7 5.3 | 1.9 35.4 250 13 7 9.6 5.3
13500 3.2 37.8 250 12 6 9.4 5.2 | 3.4 38.1 250 13 7 9.6 5.3
13000 4.4 39.9 240 12 6 8.2 4.5 | 4.8 40.6 245 12 6 9.9 5.4
12500 5.6 42.1 230 13 7 8.4 4.6 | 6.2 43.2 245 12 6 9.5 5.2
12000 6.7 44.1 225 14 7 6.8 3.7 | 7.4 45.3 240 13 6 7.8 4.3
11750 7.2 45.0 220 15 8 7.0 3.9 | 8.0 46.4 240 13 7 8.4 4.6
11500 7.8 46.0 215 15 8 8.7 4.8 | 8.7 47.7 240 13 7 10.4 5.7
11250 8.4 47.1 215 16 8 7.5 4.1 | 9.4 48.9 240 13 7 9.0 5.0
11000 8.8 47.8 210 16 8 5.7 3.1 | 9.9 49.8 235 13 7 7.2 3.9
10750 9.3 48.7 210 17 9 5.4 3.0 | 10.4 50.7 235 13 7 6.8 3.7
10500 9.7 49.5 205 18 9 8.5 4.7 | 11.0 51.8 230 13 7 10.4 5.7
10250 10.4 50.7 205 18 9 8.8 4.8 | 11.8 53.2 230 13 7 11.3 6.2
10000 10.8 51.4 205 18 9 5.7 3.1 | 12.5 54.5 225 13 6 8.0 4.4
9750 11.3 52.3 205 17 9 6.5 3.6 | 13.1 55.6 220 13 6 9.0 4.9
9500 11.7 53.1 205 17 9 6.4 3.5 | 13.7 56.7 215 13 6 8.4 4.6
9250 12.1 53.8 200 17 9 4.1 2.3 | 14.2 57.6 210 13 7 7.4 4.0
9000 12.3 54.1 200 16 8 3.0 1.6 | 14.7 58.5 205 12 6 9.2 5.0
8750 12.5 54.5 200 15 8 4.0 2.2 | 15.5 59.9 205 12 6 10.9 6.0
8500 12.7 54.9 200 15 8 3.9 2.1 | 16.3 61.3 200 12 6 10.2 5.6
8250 12.9 55.2 195 14 7 5.6 3.1 | 17.0 62.6 195 12 6 10.7 5.9
8000 13.5 56.3 190 12 6 12.7 7.0 | 18.0 64.4 195 12 6 17.7 9.7
7750 14.7 58.5 190 11 5 21.3 11.7 | 19.7 67.5 190 11 6 27.7 15.2
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
05/29/2024 at 1500 MDT | 05/29/2024 at 1800 MDT
|
CAPE... +672.5 LI... -2.3 | CAPE... +154.0 LI... -0.2
CINH... -14.6 K Index... +25.5 | CINH... -75.5 K Index... +27.4
|
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 -55.3 -67.5 255 27 14 0.4 0.2 | -56.4 -69.5 260 27 14 0.4 0.2
45000 -55.4 -67.7 260 34 18 -2.6 -1.5 | -56.4 -69.5 270 31 16 -1.9 -1.1
40000 -59.4 -74.9 265 45 23 -1.8 -1.0 | -59.3 -74.7 275 35 18 -0.6 -0.3
38000 -56.1 -69.0 260 45 23 6.2 3.4 | -56.2 -69.2 270 36 18 5.7 3.1
36000 -52.3 -62.1 260 46 24 6.2 3.4 | -52.7 -62.9 270 36 19 5.7 3.1
34000 -47.4 -53.3 260 45 23 8.1 4.4 | -47.4 -53.3 265 34 18 9.3 5.1
32000 -42.5 -44.5 265 43 22 8.1 4.5 | -41.8 -43.2 265 31 16 9.4 5.1
30000 -37.6 -35.7 265 38 19 8.2 4.5 | -36.1 -33.0 260 28 14 9.7 5.3
29000 -35.2 -31.4 265 34 17 8.2 4.5 | -33.2 -27.8 260 26 14 9.7 5.3
28000 -32.7 -26.9 265 30 15 8.2 4.5 | -30.3 -22.5 255 25 13 9.9 5.5
27000 -30.2 -22.4 265 27 14 8.6 4.7 | -27.8 -18.0 250 24 12 8.2 4.5
26000 -27.6 -17.7 260 24 12 8.6 4.7 | -25.3 -13.5 250 23 12 8.2 4.5
25000 -25.1 -13.2 255 22 11 8.7 4.8 | -22.9 -9.2 245 23 12 8.2 4.5
24000 -22.7 -8.9 255 20 10 7.6 4.2 | -20.6 -5.1 245 22 11 7.7 4.2
23000 -20.5 -4.9 260 19 10 7.6 4.2 | -18.3 -0.9 240 20 11 7.7 4.2
22000 -18.2 -0.8 260 19 10 7.7 4.2 | -16.1 3.0 240 19 10 7.7 4.2
21000 -16.0 3.2 260 18 9 7.4 4.1 | -13.5 7.7 235 17 9 6.7 3.7
20000 -13.9 7.0 260 17 9 7.5 4.1 | -11.6 11.1 235 16 8 6.7 3.7
19500 -12.2 10.0 255 16 8 7.5 4.1 | -10.6 12.9 230 15 8 6.8 3.7
19000 -11.2 11.8 255 15 8 7.3 4.0 | -9.7 14.5 230 14 7 6.4 3.5
18500 -10.1 13.8 250 15 8 7.3 4.0 | -8.7 16.3 225 14 7 6.4 3.5
18000 -9.0 15.8 250 14 7 8.2 4.5 | -7.8 18.0 225 13 7 6.3 3.5
17500 -7.6 18.3 250 14 7 9.6 5.3 | -6.9 19.6 220 13 7 5.9 3.2
17000 -6.2 20.8 245 14 7 9.6 5.3 | -6.1 21.0 215 12 6 5.9 3.2
16500 -4.7 23.5 245 14 7 9.8 5.4 | -5.2 22.6 210 12 6 6.1 3.4
16000 -3.3 26.1 245 13 7 9.8 5.4 | -4.3 24.3 205 11 6 6.2 3.4
15500 -1.8 28.8 245 13 7 9.7 5.3 | -3.5 25.7 200 11 6 6.2 3.4
15000 -0.4 31.3 240 13 7 9.7 5.3 | -2.6 27.3 195 10 5 6.2 3.4
14500 1.1 34.0 235 13 7 9.6 5.3 | -1.7 28.9 190 9 5 6.3 3.5
14000 2.5 36.5 235 13 7 9.5 5.2 | -0.7 30.7 185 7 4 6.9 3.8
13500 3.9 39.0 230 13 7 9.5 5.2 | 0.3 32.5 180 5 3 6.7 3.7
13000 5.4 41.7 225 13 7 9.6 5.3 | 1.4 34.5 175 3 2 8.9 4.9
12500 6.7 44.1 220 13 7 9.4 5.1 | 2.7 36.9 170 3 1 8.6 4.7
12000 8.0 46.4 215 13 7 7.9 4.3 | 4.0 39.2 165 2 1 9.1 5.0
11750 8.6 47.5 215 14 7 8.7 4.8 | 4.7 40.5 165 2 1 9.2 5.0
11500 9.3 48.7 210 14 7 11.0 6.0 | 5.4 41.7 160 1 1 10.2 5.6
11250 10.1 50.2 210 14 7 9.9 5.4 | 6.2 43.2 140 1 1 9.9 5.4
11000 10.7 51.3 205 15 8 7.8 4.3 | 6.8 44.2 120 1 0 8.7 4.8
10750 11.3 52.3 200 15 8 7.5 4.1 | 7.5 45.5 095 1 0 8.2 4.5
10500 11.8 53.2 195 15 8 9.7 5.3 | 8.1 46.6 060 1 0 9.7 5.3
10250 12.7 54.9 195 15 8 11.2 6.1 | 8.9 48.0 045 1 1 11.3 6.2
10000 13.4 56.1 190 15 8 9.5 5.2 | 9.7 49.5 040 1 1 10.3 5.6
9750 14.1 57.4 185 16 8 9.4 5.1 | 10.5 50.9 035 2 1 9.7 5.3
9500 14.8 58.6 180 16 8 9.9 5.4 | 11.2 52.2 030 2 1 10.0 5.5
9250 15.5 59.9 180 16 8 7.9 4.3 | 11.9 53.4 025 2 1 9.3 5.1
9000 16.0 60.8 180 16 8 8.5 4.7 | 12.6 54.7 020 2 1 9.8 5.4
8750 16.8 62.2 175 16 8 11.0 6.0 | 13.4 56.1 020 2 1 10.9 6.0
8500 17.5 63.5 175 16 8 10.6 5.8 | 14.2 57.6 020 3 1 10.5 5.7
8250 18.3 64.9 175 16 8 9.5 5.2 | 15.0 59.0 020 3 1 11.1 6.1
8000 19.0 66.2 170 15 8 9.1 5.0 | 15.9 60.6 010 3 2 10.7 5.9
7750 19.7 67.5 170 13 7 12.0 6.6 | 17.3 63.1 360 4 2 13.0 7.2
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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