Soaring Guidance
Issued by NWS Denver/Boulder, CO
Issued by NWS Denver/Boulder, CO
013
UXUS97 KBOU 291224
SRGBOU
Soaring Forecast
National Weather Service Denver/Boulder, Colorado
0623 MDT Wednesday, May 29, 2024
This forecast is for Wednesday, May 29, 2024:
If the trigger temperature of 75.1 F/24.0 C is reached...then
Thermal Soaring Index....................... Excellent
Maximum rate of lift........................ 1100 ft/min (5.6 m/s)
Maximum height of thermals.................. 20737 ft MSL (15388 ft AGL)
Forecast maximum temperature................... 84.0 F/29.3 C
Time of trigger temperature.................... 1030 MDT
Time of overdevelopment........................ 1400 MDT
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................. 11767 ft MSL (6418 ft AGL)
Thermal soaring outlook for Thursday 05/30..... Fair
Wave Soaring Index............................. Poor
Wave Soaring Index trend (to 1800 MDT)......... No change
Height of stable layer (12-18K ft MSL)......... None
Weak PVA/NVA (through 1800 MDT)................ Weak PVA
Potential height of wave....................... 40213 ft MSL (34864 ft AGL)
Wave soaring outlook for Thursday 05/30........ Good
Remarks... None
Sunrise/Sunset.................... 05:34:21 / 20:19:41 MDT
Total possible sunshine........... 14 hr 45 min 20 sec (885 min 20 sec)
Altitude of sun at 12:57:01 MDT... 72.00 degrees
Upper air data from numerical model forecast valid on 05/29/2024 at 0600 MDT
Freezing level.................. 14269 ft MSL (8920 ft AGL)
Convective condensation level... 15201 ft MSL (9852 ft AGL)
Lifted condensation level....... 16021 ft MSL (10672 ft AGL)
Lifted index.................... -5.8
K index......................... +21.9
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 29 15 1.3 0.7 M M M M M
45000 -55.2 -67.4 260 35 18 -1.9 -1.0 M M M M M
40000 -58.0 -72.4 260 42 22 -1.6 -0.9 M M M M M
38000 -55.3 -67.5 260 40 20 5.2 2.9 M M M M M
36000 -52.1 -61.8 255 36 19 5.2 2.9 M M M M M
34000 -48.3 -54.9 255 33 17 7.5 4.1 M M M M M
32000 -43.8 -46.8 260 29 15 7.5 4.1 M M M M M
30000 -38.6 -37.5 260 25 13 7.8 4.3 36.2 97.2 5.5 M M
29000 -36.3 -33.3 265 23 12 7.8 4.3 35.5 95.8 5.0 M M
28000 -33.9 -29.0 265 21 11 7.8 4.3 34.8 94.7 4.6 M M
27000 -31.6 -24.9 265 20 10 7.8 4.3 34.0 93.3 4.0 M M
26000 -29.2 -20.6 265 20 10 7.8 4.3 33.3 91.9 3.5 M M
25000 -26.9 -16.4 270 19 10 7.8 4.3 32.6 90.8 3.0 M M
24000 -24.7 -12.5 270 18 9 7.2 4.0 31.8 89.2 2.3 M M
23000 -22.5 -8.5 275 18 9 7.2 4.0 30.8 87.5 1.5 M M
22000 -20.4 -4.7 280 18 9 7.2 4.0 30.0 86.0 0.8 M M
21000 -18.1 -0.6 280 18 9 8.2 4.5 29.3 84.7 0.2 M M
20000 -15.7 3.7 280 18 9 8.3 4.5 28.7 83.7 -0.3 1431 7.3
19500 -14.5 5.9 280 18 9 8.3 4.6 28.5 83.3 -0.6 1380 7.0
19000 -13.2 8.2 285 18 9 8.7 4.8 28.3 83.0 -0.8 1329 6.8
18500 -11.9 10.6 280 18 10 9.0 4.9 28.2 82.7 -0.9 1274 6.5
18000 -10.6 12.9 280 19 10 9.0 4.9 28.1 82.5 -1.0 1220 6.2
17500 -8.5 16.7 280 18 9 9.3 5.1 27.9 82.2 -1.2 1137 5.8
17000 -7.2 19.0 280 18 9 9.3 5.1 27.8 82.1 -1.3 1081 5.5
16500 -5.8 21.6 280 18 9 9.4 5.2 27.8 82.0 -1.4 1025 5.2
16000 -4.4 24.1 275 17 9 9.4 5.2 27.7 81.9 -1.5 968 4.9
15500 -3.0 26.6 275 16 8 9.0 4.9 27.6 81.7 -1.6 912 4.6
15000 -1.7 28.9 275 15 8 8.9 4.9 27.5 81.5 -1.7 859 4.4
14500 -0.4 31.3 270 14 7 8.9 4.9 27.4 81.2 -1.9 805 4.1
14000 0.9 33.6 265 14 7 8.8 4.8 27.2 80.9 -2.1 752 3.8
13500 2.1 35.8 260 13 7 8.8 4.8 27.0 80.7 -2.3 698 3.5
13000 3.4 38.1 250 13 7 8.7 4.8 26.9 80.4 -2.4 645 3.3
12500 4.7 40.5 245 13 7 8.7 4.8 26.7 80.1 -2.6 592 3.0
12000 5.9 42.6 235 13 7 8.2 4.5 26.5 79.7 -2.9 541 2.7
11500 7.1 44.8 230 14 7 8.2 4.5 26.2 79.2 -3.2 490 2.5
11000 8.3 46.9 220 15 8 7.6 4.2 26.0 78.7 -3.5 440 2.2
10500 9.4 48.9 215 16 8 6.2 3.4 25.7 78.2 -3.8 392 2.0
10250 9.7 49.5 215 16 8 3.8 2.1 25.2 77.4 -4.2 374 1.9
10000 10.1 50.2 210 17 9 7.7 4.2 24.9 76.8 -4.6 356 1.8
9750 10.8 51.4 210 17 9 10.4 5.7 24.9 76.8 -4.6 327 1.7
9500 11.5 52.7 210 17 9 9.4 5.2 24.9 76.8 -4.6 299 1.5
9250 12.1 53.8 210 17 9 6.6 3.6 24.8 76.6 -4.8 273 1.4
9000 12.5 54.5 210 18 9 5.6 3.1 24.5 76.0 -5.1 254 1.3
8750 13.0 55.4 215 18 9 7.1 3.9 24.2 75.6 -5.4 232 1.2
8500 13.5 56.3 215 18 9 6.1 3.4 24.0 75.2 -5.6 210 1.1
8250 13.9 57.0 215 18 9 4.6 2.5 23.6 74.6 -6.0 192 1.0
8000 14.1 57.4 215 18 9 3.4 1.8 23.2 73.8 -6.5 176 0.9
7750 14.4 57.9 220 17 9 2.9 1.6 22.7 72.8 -7.0 162 0.8
7500 14.5 58.1 220 16 8 1.5 0.8 22.1 71.8 -7.6 150 0.8
7250 14.5 58.1 220 15 8 0.1 0.1 21.4 70.6 -8.3 142 0.7
7000 14.5 58.1 225 14 7 0.1 0.1 20.7 69.2 -9.1 135 0.7
6750 14.5 58.1 230 13 7 0.8 0.4 20.0 68.0 -9.8 128 0.6
6500 14.5 58.1 230 10 5 -0.1 -0.1 19.3 66.7 -10.6 120 0.6
6250 14.4 57.9 225 10 5 -1.7 -1.0 18.5 65.2 -11.5 117 0.6
6000 14.3 57.7 225 9 4 0.3 0.1 17.6 63.8 -12.4 114 0.6
5750 14.1 57.4 225 8 4 -5.8 -3.2 16.8 62.3 -13.2 110 0.6
5500 13.0 55.4 220 5 3 -22.2 -12.2 15.0 59.1 -15.1 136 0.7
* * * * * * Numerical weather prediction model forecast data valid * * * * * *
05/29/2024 at 0900 MDT | 05/29/2024 at 1200 MDT
|
CAPE... +272.7 LI... -1.8 | CAPE... +918.4 LI... -3.5
CINH... -243.1 K Index... +19.7 | CINH... -24.4 K Index... +18.8
|
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 -55.8 -68.4 270 27 14 0.7 0.4 | -55.4 -67.7 265 24 12 0.2 0.1
45000 -55.4 -67.7 265 33 17 -2.0 -1.1 | -55.6 -68.1 270 32 16 -1.8 -1.0
40000 -58.5 -73.3 260 45 23 -1.7 -0.9 | -58.3 -72.9 260 47 24 -1.2 -0.7
38000 -55.5 -67.9 260 45 23 5.6 3.1 | -55.4 -67.7 260 46 24 5.4 2.9
36000 -52.2 -62.0 265 45 23 5.6 3.1 | -52.2 -62.0 255 45 23 5.4 2.9
34000 -48.1 -54.6 265 43 22 7.9 4.3 | -48.1 -54.6 255 43 22 8.1 4.5
32000 -43.4 -46.1 265 38 20 7.9 4.3 | -43.2 -45.8 255 39 20 8.1 4.5
30000 -38.2 -36.8 265 32 16 7.7 4.2 | -37.9 -36.2 260 33 17 7.7 4.2
29000 -35.9 -32.6 265 28 15 7.7 4.2 | -35.6 -32.1 260 29 15 7.7 4.2
28000 -33.6 -28.5 265 25 13 7.7 4.2 | -33.3 -27.9 265 25 13 7.7 4.2
27000 -31.4 -24.5 260 23 12 7.5 4.1 | -31.1 -24.0 265 23 12 7.4 4.0
26000 -29.1 -20.4 260 21 11 7.5 4.1 | -28.9 -20.0 260 21 11 7.4 4.0
25000 -26.9 -16.4 260 19 10 7.5 4.1 | -26.7 -16.1 260 19 10 7.4 4.0
24000 -24.7 -12.5 265 17 9 7.1 3.9 | -24.6 -12.3 255 18 9 6.8 3.7
23000 -22.6 -8.7 265 15 8 7.1 3.9 | -22.6 -8.7 250 17 9 6.8 3.7
22000 -20.5 -4.9 270 12 6 7.1 3.9 | -20.6 -5.1 245 16 8 6.7 3.7
21000 -18.2 -0.8 275 11 6 8.5 4.6 | -18.2 -0.8 245 15 8 8.9 4.9
20000 -15.7 3.7 280 11 5 8.5 4.7 | -15.5 4.1 250 13 7 8.9 4.9
19500 -14.4 6.1 280 10 5 8.5 4.7 | -14.2 6.4 250 13 7 9.0 4.9
19000 -13.2 8.2 285 10 5 8.8 4.8 | -12.9 8.8 250 12 6 9.1 5.0
18500 -11.8 10.8 280 11 5 9.0 4.9 | -11.6 11.1 255 12 6 9.1 5.0
18000 -10.5 13.1 280 11 6 9.0 4.9 | -10.2 13.6 255 12 6 9.1 5.0
17500 -9.1 15.6 280 11 6 9.4 5.2 | -8.8 16.2 260 13 6 9.1 5.0
17000 -7.0 19.4 275 12 6 9.4 5.1 | -7.5 18.5 260 13 7 9.1 5.0
16500 -5.7 21.7 275 12 6 9.2 5.0 | -6.1 21.0 260 13 7 9.3 5.1
16000 -4.3 24.3 270 12 6 9.2 5.1 | -4.7 23.5 260 13 7 9.3 5.1
15500 -3.0 26.6 270 12 6 9.1 5.0 | -2.7 27.1 260 13 7 9.4 5.1
15000 -1.6 29.1 270 11 6 9.1 5.0 | -1.3 29.7 260 12 6 9.4 5.1
14500 -0.3 31.5 265 11 6 9.2 5.0 | 0.1 32.2 260 12 6 9.4 5.1
14000 1.1 34.0 265 11 6 9.3 5.1 | 1.5 34.7 260 12 6 9.4 5.1
13500 2.5 36.5 260 11 6 9.3 5.1 | 2.9 37.2 260 12 6 9.4 5.1
13000 3.8 38.8 260 11 6 9.2 5.0 | 4.3 39.7 260 11 6 9.4 5.2
12500 5.2 41.4 255 11 6 9.1 5.0 | 5.7 42.3 260 11 6 9.4 5.2
12000 6.5 43.7 250 12 6 8.5 4.7 | 7.1 44.8 260 11 6 9.5 5.2
11500 7.7 45.9 245 12 6 8.6 4.7 | 8.5 47.3 260 10 5 9.4 5.2
11000 9.0 48.2 240 13 7 8.6 4.7 | 9.8 49.6 255 10 5 8.7 4.8
10500 10.3 50.5 235 13 7 5.9 3.2 | 11.2 52.2 255 10 5 4.1 2.2
10250 10.6 51.1 235 13 6 4.5 2.5 | 11.3 52.3 250 9 5 5.4 2.9
10000 11.1 52.0 235 13 7 9.4 5.1 | 12.1 53.8 250 9 5 12.6 6.9
9750 11.8 53.2 230 13 7 10.5 5.7 | 12.9 55.2 245 9 5 10.8 5.9
9500 12.6 54.7 230 14 7 9.7 5.3 | 13.8 56.8 245 9 5 10.7 5.9
9250 13.2 55.8 230 14 7 6.7 3.7 | 14.4 57.9 240 8 4 7.4 4.1
9000 13.6 56.5 230 13 7 6.5 3.6 | 14.9 58.8 235 7 4 7.7 4.2
8750 14.2 57.6 225 14 7 8.6 4.7 | 15.6 60.1 230 7 4 9.8 5.4
8500 14.7 58.5 225 15 7 7.1 3.9 | 16.2 61.2 230 7 3 8.7 4.8
8250 15.2 59.4 225 15 8 5.0 2.7 | 16.7 62.1 225 6 3 6.3 3.5
8000 15.5 59.9 225 14 7 3.7 2.0 | 17.1 62.8 215 4 2 6.6 3.6
7750 15.7 60.3 220 14 7 3.9 2.2 | 17.6 63.7 220 3 2 8.4 4.6
7500 15.9 60.6 220 14 7 2.0 1.1 | 18.2 64.8 225 3 1 8.1 4.5
7250 15.9 60.6 220 13 6 -0.4 -0.2 | 18.8 65.8 230 2 1 7.7 4.2
7000 15.9 60.6 220 11 6 -0.1 -0.1 | 19.3 66.7 225 1 1 8.4 4.6
6750 15.9 60.6 220 10 5 1.9 1.0 | 20.0 68.0 235 1 1 11.7 6.4
6500 16.1 61.0 215 9 5 5.4 2.9 | 21.0 69.8 245 2 1 12.0 6.6
6250 16.5 61.7 215 8 4 7.1 3.9 | 21.8 71.2 250 1 1 10.9 6.0
6000 17.0 62.6 210 6 3 5.5 3.0 | 22.6 72.7 270 1 0 10.1 5.5
5750 17.4 63.3 210 4 2 9.3 5.1 | 23.4 74.1 290 1 0 13.3 7.3
5500 18.5 65.3 210 4 2 20.8 11.4 | 24.8 76.6 280 1 0 26.2 14.4
05/29/2024 at 1500 MDT | 05/29/2024 at 1800 MDT
|
CAPE... +231.8 LI... -0.6 | CAPE... +191.0 LI... -0.7
CINH... -28.5 K Index... +24.2 | CINH... -81.9 K Index... +23.5
|
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 -55.4 -67.7 260 25 13 0.5 0.3 | -56.3 -69.3 260 27 14 0.0 0.0
45000 -55.3 -67.5 265 30 16 -2.0 -1.1 | -56.6 -69.9 265 31 16 -0.9 -0.5
40000 -58.3 -72.9 270 42 22 -1.6 -0.9 | -57.9 -72.2 270 42 22 -0.4 -0.2
38000 -55.3 -67.5 265 42 22 5.7 3.1 | -55.1 -67.2 265 40 21 5.2 2.8
36000 -52.0 -61.6 265 42 22 5.7 3.1 | -52.0 -61.6 265 37 19 5.2 2.8
34000 -47.9 -54.2 260 40 20 7.6 4.2 | -48.0 -54.4 260 32 17 8.0 4.4
32000 -42.8 -45.0 255 35 18 7.7 4.2 | -43.2 -45.8 260 26 14 8.0 4.4
30000 -38.1 -36.6 255 30 15 7.9 4.3 | -37.8 -36.0 250 21 11 7.9 4.3
29000 -35.8 -32.4 255 27 14 7.9 4.3 | -35.5 -31.9 245 19 10 7.9 4.3
28000 -33.4 -28.1 250 24 12 7.9 4.3 | -33.1 -27.6 240 18 9 7.9 4.3
27000 -31.0 -23.8 250 23 12 8.1 4.4 | -30.7 -23.3 235 18 9 7.9 4.4
26000 -28.6 -19.5 250 21 11 8.1 4.4 | -28.4 -19.1 235 18 9 8.0 4.4
25000 -26.2 -15.2 245 20 10 8.1 4.5 | -26.0 -14.8 235 18 9 8.0 4.4
24000 -23.9 -11.0 245 19 10 7.7 4.2 | -23.7 -10.7 235 18 9 7.8 4.3
23000 -21.6 -6.9 250 18 9 7.7 4.3 | -21.4 -6.5 240 18 9 7.8 4.3
22000 -19.3 -2.7 250 17 9 7.8 4.3 | -19.1 -2.4 240 18 9 7.8 4.3
21000 -17.0 1.4 250 16 8 7.7 4.2 | -16.8 1.8 245 17 9 7.7 4.2
20000 -14.8 5.4 250 15 8 7.7 4.2 | -14.6 5.7 250 16 8 7.7 4.3
19500 -13.6 7.5 250 14 7 7.8 4.3 | -13.4 7.9 255 15 8 7.8 4.3
19000 -12.5 9.5 250 14 7 7.8 4.3 | -12.3 9.9 255 15 8 7.9 4.3
18500 -11.3 11.7 250 13 7 7.9 4.3 | -11.1 12.0 260 14 7 8.0 4.4
18000 -10.2 13.6 250 12 6 7.9 4.3 | -10.0 14.0 260 14 7 8.0 4.4
17500 -8.4 16.9 245 11 6 8.2 4.5 | -8.2 17.2 265 13 7 8.3 4.5
17000 -7.2 19.0 245 11 6 8.2 4.5 | -6.9 19.6 270 13 7 8.2 4.5
16500 -5.9 21.4 245 10 5 8.9 4.9 | -5.7 21.7 270 13 6 8.8 4.9
16000 -4.6 23.7 245 10 5 8.8 4.8 | -4.4 24.1 275 12 6 8.8 4.8
15500 -3.3 26.1 245 10 5 9.2 5.0 | -3.1 26.4 275 12 6 8.9 4.9
15000 -1.9 28.6 245 9 5 9.3 5.1 | -1.8 28.8 275 12 6 9.0 4.9
14500 -0.6 30.9 245 9 5 9.3 5.1 | -0.4 31.3 275 12 6 9.1 5.0
14000 0.8 33.4 245 8 4 9.4 5.2 | 1.0 33.8 275 12 6 9.4 5.2
13500 2.2 36.0 245 8 4 9.5 5.2 | 2.4 36.3 275 11 6 9.4 5.1
13000 3.7 38.7 245 8 4 9.8 5.4 | 3.7 38.7 270 11 6 9.2 5.1
12500 5.1 41.2 240 8 4 9.8 5.4 | 5.1 41.2 270 11 5 9.2 5.1
12000 6.6 43.9 240 7 4 9.8 5.4 | 6.5 43.7 265 10 5 9.3 5.1
11500 8.1 46.6 240 7 4 9.9 5.4 | 7.9 46.2 260 10 5 9.5 5.2
11000 9.3 48.7 240 6 3 7.9 4.3 | 9.2 48.6 260 10 5 8.0 4.4
10500 10.5 50.9 240 5 3 12.7 7.0 | 10.3 50.5 255 10 5 9.6 5.3
10250 11.7 53.1 245 7 3 14.0 7.7 | 11.2 52.2 255 10 5 11.4 6.2
10000 12.4 54.3 245 6 3 8.7 4.8 | 11.9 53.4 250 11 5 9.6 5.2
9750 13.2 55.8 245 6 3 10.1 5.6 | 12.6 54.7 250 11 6 9.0 4.9
9500 13.9 57.0 245 6 3 9.7 5.3 | 13.3 55.9 250 11 6 9.1 5.0
9250 14.6 58.3 245 6 3 7.9 4.3 | 14.0 57.2 245 11 6 9.1 5.0
9000 15.1 59.2 240 4 2 8.8 4.8 | 14.6 58.3 245 10 5 9.4 5.1
8750 15.9 60.6 245 5 3 10.9 6.0 | 15.3 59.5 245 11 6 9.4 5.2
8500 16.7 62.1 250 6 3 10.2 5.6 | 16.0 60.8 245 11 6 9.4 5.2
8250 17.4 63.3 250 6 3 8.7 4.8 | 16.7 62.1 245 12 6 9.6 5.3
8000 18.0 64.4 250 4 2 9.0 4.9 | 17.4 63.3 245 11 6 9.3 5.1
7750 18.8 65.8 255 5 2 10.8 5.9 | 18.1 64.6 245 12 6 8.8 4.8
7500 19.6 67.3 255 6 3 9.7 5.3 | 18.7 65.7 245 13 6 8.5 4.7
7250 20.2 68.4 260 6 3 7.4 4.1 | 19.3 66.7 245 13 7 7.3 4.0
7000 20.7 69.3 265 5 2 7.5 4.1 | 19.8 67.6 245 13 7 7.1 3.9
6750 21.4 70.5 265 5 2 12.1 6.6 | 20.4 68.7 245 14 7 9.9 5.4
6500 22.4 72.3 265 7 4 10.0 5.5 | 21.2 70.2 245 15 8 8.4 4.6
6250 22.9 73.2 270 6 3 5.8 3.2 | 21.6 70.9 245 15 8 5.0 2.8
6000 23.3 73.9 270 6 3 6.1 3.4 | 21.9 71.4 245 13 7 5.1 2.8
5750 23.8 74.8 270 6 3 7.5 4.1 | 22.2 72.0 240 12 6 4.1 2.2
5500 24.5 76.1 270 7 4 14.1 7.8 | 22.5 72.5 240 12 6 7.2 4.0
________________________________________________________________________________
This product is issued twice per day, once by approximately 0630 MST/0730 MDT
(1330 UTC) and again by approximately 1830 MST/1930 MDT (0130 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 old Stapleton
Airport site in Denver, Colorado at
North Latitude: 39 deg 46 min 5.016 sec
West Longitude: 104 deg 52 min 9.984 sec
Elevation: 5285 feet (1611 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.
CINH (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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