Soaring Guidance
Issued by NWS Denver/Boulder, CO
Issued by NWS Denver/Boulder, CO
349
UXUS97 KBOU 020112
SRGBOU
Soaring Forecast
National Weather Service Denver/Boulder, Colorado
1912 MDT Monday, July 1, 2024
This forecast is for Tuesday, July 2, 2024:
If the trigger temperature of 73.0 F/22.8 C is reached...then
Thermal Soaring Index....................... Excellent
Maximum rate of lift........................ 871 ft/min (4.4 m/s)
Maximum height of thermals.................. 15987 ft MSL (10673 ft AGL)
Forecast maximum temperature................... 86.0 F/30.5 C
Time of trigger temperature.................... 1045 MDT
Time of overdevelopment........................ None
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................. 13332 ft MSL (8018 ft AGL)
Thermal soaring outlook for Wednesday 07/03.... Good
Wave Soaring Index............................. Poor
Wave Soaring Index trend (to 1800 MDT).........
Height of stable layer (12-18K ft MSL)......... None
Weak PVA/NVA (through 1800 MDT)................ Neither
Potential height of wave....................... 36010 ft MSL (30696 ft AGL)
Wave soaring outlook for Wednesday 07/03....... Poor
Remarks...
Sunrise/Sunset.................... 05:36:07 / 20:31:18 MDT
Total possible sunshine........... 14 hr 55 min 12 sec (895 min 12 sec)
Altitude of sun at 13:03:43 MDT... 73.17 degrees
Upper air data from numerical model forecast valid on 07/02/2024 at 0600 MDT
Freezing level.................. 14829 ft MSL (9515 ft AGL)
Convective condensation level... 12575 ft MSL (7261 ft AGL)
Lifted condensation level....... 14201 ft MSL (8886 ft AGL)
Lifted index.................... -2.8
K index......................... +29.5
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 -61.4 -78.5 265 32 16 3.7 2.0 M M M M M
45000 -54.9 -66.8 255 41 21 5.5 3.0 M M M M M
40000 -46.3 -51.3 245 56 29 5.4 2.9 M M M M M
38000 -43.1 -45.6 240 60 31 5.4 2.9 M M M M M
36000 -39.9 -39.8 235 64 33 5.2 2.9 M M M M M
34000 -36.2 -33.2 235 64 33 6.4 3.5 M M M M M
32000 -32.3 -26.1 235 62 32 6.4 3.5 M M M M M
30000 -28.3 -18.9 240 60 31 6.8 3.7 48.9 120.0 14.4 M M
29000 -25.8 -14.4 245 59 30 6.8 3.7 47.5 117.5 13.5 M M
28000 -23.8 -10.8 250 58 30 6.8 3.8 46.5 115.8 12.9 M M
27000 -21.7 -7.1 250 57 30 6.9 3.8 45.3 113.5 12.1 M M
26000 -19.7 -3.5 250 57 29 6.9 3.8 44.2 111.6 11.3 M M
25000 -17.6 0.3 250 57 29 7.3 4.0 43.3 109.9 10.7 M M
24000 -16.1 3.0 250 53 27 4.5 2.5 41.5 106.6 9.3 M M
23000 -14.9 5.2 250 49 25 4.7 2.6 39.6 103.2 7.7 M M
22000 -13.6 7.5 250 44 23 4.8 2.6 37.8 100.1 6.2 M M
21000 -11.7 10.9 245 41 21 7.2 3.9 36.7 98.0 5.2 M M
20000 -9.6 14.7 240 38 20 7.2 3.9 35.7 96.3 4.4 M M
19500 -8.6 16.5 240 37 19 7.2 4.0 35.3 95.6 4.0 M M
19000 -7.6 18.3 240 36 18 6.8 3.7 34.9 94.8 3.7 M M
18500 -6.6 20.1 240 34 18 6.7 3.7 34.4 93.8 3.1 M M
18000 -5.7 21.7 240 33 17 6.7 3.7 33.8 92.9 2.7 M M
17500 -4.8 23.4 240 32 16 5.5 3.0 33.2 91.8 2.1 M M
17000 -4.0 24.8 245 30 15 5.7 3.1 32.5 90.5 1.4 M M
16500 -3.2 26.2 245 28 14 5.8 3.2 31.8 89.3 0.8 M M
16000 -2.4 27.7 245 27 14 5.9 3.3 31.2 88.1 0.2 M M
15500 -1.1 30.0 240 25 13 6.5 3.6 30.3 86.5 -0.7 821 4.2
15000 -0.1 31.8 245 23 12 6.6 3.6 29.7 85.5 -1.2 778 4.0
14500 0.8 33.4 245 22 11 6.4 3.5 29.2 84.6 -1.8 735 3.7
14000 1.7 35.1 245 21 11 6.2 3.4 28.6 83.6 -2.3 694 3.5
13500 2.6 36.7 245 19 10 6.5 3.6 28.1 82.5 -2.9 652 3.3
13000 3.6 38.5 245 18 9 7.5 4.1 27.7 81.8 -3.4 607 3.1
12500 4.7 40.5 245 17 9 7.4 4.1 27.3 81.1 -3.8 560 2.8
12000 5.7 42.3 245 16 8 6.9 3.8 26.9 80.3 -4.2 514 2.6
11500 6.8 44.2 250 15 8 7.0 3.8 26.4 79.6 -4.7 469 2.4
11000 7.8 46.0 255 14 7 6.7 3.7 26.0 78.7 -5.1 424 2.2
10500 8.8 47.8 265 12 6 5.2 2.9 25.5 77.9 -5.6 379 1.9
10250 9.1 48.4 265 11 6 3.9 2.1 25.1 77.1 -6.0 363 1.8
10000 9.4 48.9 275 10 5 6.9 3.8 24.7 76.5 -6.4 344 1.7
9750 10.0 50.0 285 9 4 7.9 4.3 24.5 76.2 -6.6 320 1.6
9500 10.5 50.9 295 8 4 7.6 4.2 24.4 75.9 -6.8 296 1.5
9250 11.1 52.0 310 8 4 6.7 3.7 24.2 75.6 -7.0 273 1.4
9000 11.6 52.9 320 8 4 7.1 3.9 24.0 75.1 -7.3 251 1.3
8750 12.1 53.8 335 9 5 7.9 4.4 23.8 74.8 -7.4 227 1.2
8500 12.7 54.9 340 10 5 7.8 4.3 23.6 74.6 -7.6 202 1.0
8250 13.3 55.9 350 11 6 8.6 4.7 23.5 74.4 -7.8 177 0.9
8000 13.9 57.0 355 13 6 8.1 4.5 23.4 74.2 -7.9 151 0.8
7750 14.4 57.9 355 14 7 6.7 3.7 23.3 73.9 -8.1 127 0.6
7500 15.0 59.0 360 15 8 7.2 3.9 23.0 73.5 -8.3 105 0.5
7250 15.5 59.9 360 17 9 8.0 4.4 22.9 73.2 -8.5 80 0.4
7000 16.1 61.0 005 19 10 7.8 4.3 22.7 72.9 -8.7 55 0.3
6750 16.7 62.1 005 21 11 6.5 3.5 22.6 72.6 -8.9 32 0.2
6500 17.1 62.8 010 22 11 6.7 3.7 22.3 72.1 -9.1 10 0.1
6250 17.7 63.9 010 21 11 7.8 4.3 22.1 71.8 -9.4 M M
6000 18.2 64.8 010 19 10 7.5 4.1 22.0 71.5 -9.6 M M
5750 18.7 65.7 010 17 9 8.0 4.4 21.8 71.3 -9.8 M M
5500 19.3 66.7 015 14 7 8.8 4.8 21.7 71.1 -10.0 M M
* * * * * * Numerical weather prediction model forecast data valid * * * * * *
07/02/2024 at 0900 MDT | 07/02/2024 at 1200 MDT
|
CAPE... +9.8 LI... -2.9 | CAPE... +65.9 LI... -1.4
CINH... -58.3 K Index... +23.3 | CINH... -46.5 K Index... +23.1
|
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 -60.5 -76.9 260 29 15 3.5 1.9 | -60.0 -76.0 260 25 13 3.2 1.7
45000 -54.3 -65.7 255 41 21 5.4 3.0 | -54.2 -65.6 260 41 21 5.3 2.9
40000 -45.9 -50.6 255 59 30 4.7 2.6 | -46.1 -51.0 255 61 32 4.3 2.4
38000 -43.1 -45.6 250 65 33 4.7 2.6 | -43.5 -46.3 250 66 34 4.3 2.4
36000 -40.3 -40.5 245 71 36 4.6 2.5 | -41.0 -41.8 250 71 37 4.2 2.3
34000 -37.0 -34.6 245 69 36 5.7 3.1 | -37.8 -36.0 250 70 36 5.5 3.0
32000 -33.7 -28.7 245 67 34 5.7 3.1 | -34.5 -30.1 250 68 35 5.6 3.1
30000 -29.5 -21.1 250 65 33 7.4 4.1 | -30.1 -22.2 250 65 34 8.0 4.4
29000 -26.7 -16.1 250 63 33 7.4 4.1 | -27.1 -16.8 255 64 33 8.0 4.4
28000 -24.5 -12.1 255 63 32 7.5 4.1 | -24.7 -12.5 255 62 32 8.2 4.5
27000 -22.2 -8.0 255 62 32 7.6 4.2 | -22.2 -8.0 255 60 31 8.3 4.5
26000 -20.0 -4.0 250 62 32 7.6 4.2 | -19.8 -3.6 255 57 30 8.3 4.5
25000 -17.7 0.1 250 61 32 7.9 4.3 | -17.3 0.9 255 55 28 8.6 4.7
24000 -16.0 3.2 250 58 30 5.1 2.8 | -15.8 3.6 255 54 28 4.0 2.2
23000 -14.4 6.1 250 54 28 5.2 2.8 | -14.6 5.7 250 53 27 4.1 2.3
22000 -12.9 8.8 245 50 26 5.3 2.9 | -13.4 7.9 245 52 27 4.2 2.3
21000 -11.7 10.9 245 45 23 3.9 2.1 | -12.1 10.2 250 49 25 4.7 2.6
20000 -10.6 12.9 240 40 21 4.0 2.2 | -10.8 12.6 250 45 23 4.9 2.7
19500 -10.0 14.0 240 38 19 4.0 2.2 | -10.1 13.8 250 43 22 5.0 2.8
19000 -9.3 15.3 240 36 18 7.5 4.1 | -9.4 15.1 255 42 22 6.4 3.5
18500 -8.0 17.6 245 36 19 8.7 4.8 | -8.4 16.9 255 42 22 6.7 3.7
18000 -6.7 19.9 250 37 19 8.7 4.8 | -7.4 18.7 255 43 22 6.7 3.7
17500 -5.6 21.9 255 37 19 6.6 3.6 | -6.5 20.3 255 42 22 6.6 3.6
17000 -4.6 23.7 255 38 19 6.8 3.7 | -5.5 22.1 255 42 21 6.6 3.6
16500 -3.7 25.3 255 38 19 7.2 3.9 | -4.5 23.9 260 40 21 7.0 3.8
16000 -2.6 27.3 255 36 18 7.3 4.0 | -3.5 25.7 260 38 20 7.1 3.9
15500 -1.6 29.1 260 34 17 7.5 4.1 | -2.4 27.7 265 36 19 7.3 4.0
15000 -0.0 32.0 260 31 16 7.6 4.2 | -1.3 29.7 265 34 18 7.6 4.2
14500 1.0 33.8 260 28 15 6.9 3.8 | 0.3 32.5 265 32 16 7.4 4.1
14000 1.9 35.4 260 25 13 6.4 3.5 | 1.4 34.5 270 30 15 7.3 4.0
13500 2.7 36.9 255 22 11 6.3 3.5 | 2.4 36.3 270 28 14 7.4 4.0
13000 3.5 38.3 255 20 10 6.0 3.3 | 3.5 38.3 270 27 14 7.4 4.1
12500 4.3 39.7 250 17 9 6.3 3.4 | 4.6 40.3 275 26 14 7.6 4.2
12000 5.2 41.4 250 16 8 7.1 3.9 | 5.7 42.3 275 25 13 8.0 4.4
11500 6.3 43.3 250 14 7 7.1 3.9 | 6.9 44.4 275 23 12 8.0 4.4
11000 7.3 45.1 260 14 7 7.3 4.0 | 8.0 46.4 275 21 11 7.5 4.1
10500 8.5 47.3 265 14 7 5.5 3.0 | 9.1 48.4 275 19 10 3.7 2.1
10250 8.7 47.7 270 14 7 3.8 2.1 | 9.2 48.6 275 18 9 3.9 2.2
10000 9.1 48.4 270 13 7 6.7 3.7 | 9.9 49.8 275 17 9 10.5 5.8
9750 9.7 49.5 275 13 7 7.7 4.2 | 10.6 51.1 275 16 8 10.5 5.7
9500 10.2 50.4 285 12 6 7.1 3.9 | 11.3 52.3 280 15 8 9.3 5.1
9250 10.7 51.3 285 12 6 5.7 3.2 | 11.9 53.4 280 14 7 6.7 3.7
9000 11.2 52.2 290 12 6 6.6 3.6 | 12.4 54.3 280 13 7 7.4 4.1
8750 11.7 53.1 295 11 6 8.0 4.4 | 13.0 55.4 275 12 6 8.5 4.7
8500 12.3 54.1 295 11 5 7.3 4.0 | 13.6 56.5 275 11 6 8.2 4.5
8250 12.8 55.0 295 10 5 6.7 3.7 | 14.2 57.6 275 10 5 8.4 4.6
8000 13.3 55.9 295 10 5 6.7 3.7 | 14.8 58.6 275 9 5 8.1 4.4
7750 13.8 56.8 295 9 5 7.1 3.9 | 15.3 59.5 275 8 4 7.3 4.0
7500 14.3 57.7 295 9 5 6.5 3.6 | 15.9 60.6 280 7 4 8.8 4.8
7250 14.8 58.6 295 8 4 5.9 3.2 | 16.6 61.9 275 7 4 10.2 5.6
7000 15.2 59.4 295 6 3 6.0 3.3 | 17.4 63.3 275 7 3 9.7 5.3
6750 15.7 60.3 290 5 2 6.8 3.7 | 18.1 64.6 275 7 3 9.7 5.3
6500 16.3 61.3 295 3 2 9.3 5.1 | 18.8 65.8 275 6 3 10.0 5.5
6250 17.0 62.6 300 3 1 10.8 5.9 | 19.6 67.3 275 6 3 10.6 5.8
6000 17.8 64.0 310 2 1 9.1 5.0 | 20.4 68.7 275 6 3 9.6 5.2
5750 18.5 65.3 330 1 1 12.7 7.0 | 21.1 70.0 275 6 3 12.6 6.9
5500 19.9 67.8 335 1 1 23.1 12.7 | 22.3 72.1 275 6 3 20.5 11.3
07/02/2024 at 1500 MDT | 07/02/2024 at 1800 MDT
|
CAPE... +106.7 LI... -1.4 | CAPE... +21.8 LI... -0.3
CINH... -6.7 K Index... +25.4 | CINH... -18.5 K Index... +22.6
|
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 -60.5 -76.9 250 32 17 3.4 1.9 | -60.5 -76.9 245 35 18 3.7 2.0
45000 -54.3 -65.7 250 46 24 5.6 3.1 | -53.5 -64.3 245 47 24 5.6 3.1
40000 -45.8 -50.4 255 62 32 4.2 2.3 | -45.5 -49.9 255 60 31 4.0 2.2
38000 -43.3 -45.9 250 65 33 4.2 2.3 | -43.1 -45.6 255 63 32 4.0 2.2
36000 -40.8 -41.4 250 68 35 4.1 2.3 | -40.7 -41.3 255 65 33 4.1 2.2
34000 -38.0 -36.4 250 66 34 4.7 2.6 | -38.4 -37.1 255 61 32 3.7 2.0
32000 -35.2 -31.4 250 63 32 4.8 2.6 | -36.2 -33.2 260 56 29 3.8 2.1
30000 -30.4 -22.7 255 60 31 7.8 4.3 | -31.5 -24.7 260 53 27 8.0 4.4
29000 -28.0 -18.4 260 60 31 7.8 4.3 | -29.1 -20.4 265 52 27 8.0 4.4
28000 -25.7 -14.3 260 58 30 8.8 4.8 | -26.7 -16.1 265 50 26 9.0 5.0
27000 -22.9 -9.2 255 52 27 9.2 5.0 | -23.9 -11.0 260 48 25 9.4 5.2
26000 -20.1 -4.2 250 46 24 9.2 5.0 | -21.1 -6.0 260 47 24 9.4 5.2
25000 -17.4 0.7 240 40 21 9.3 5.1 | -18.2 -0.8 255 46 23 9.2 5.1
24000 -15.4 4.3 250 42 22 6.1 3.3 | -16.1 3.0 260 45 23 6.4 3.5
23000 -13.5 7.7 260 47 24 6.1 3.4 | -14.2 6.4 265 45 23 6.5 3.5
22000 -11.7 10.9 265 53 27 6.0 3.3 | -12.3 9.9 275 45 23 6.1 3.3
21000 -10.8 12.6 265 53 27 2.4 1.3 | -11.1 12.0 275 43 22 3.5 1.9
20000 -10.0 14.0 265 50 26 2.5 1.4 | -10.1 13.8 270 39 20 3.5 1.9
19500 -9.7 14.5 265 49 25 2.5 1.4 | -9.6 14.7 270 37 19 3.5 1.9
19000 -9.3 15.3 265 48 25 3.2 1.8 | -9.0 15.8 265 36 18 4.9 2.7
18500 -8.8 16.2 265 46 24 3.6 2.0 | -8.3 17.1 265 34 17 5.3 2.9
18000 -8.4 16.9 265 44 23 4.4 2.4 | -7.6 18.3 260 32 17 6.1 3.3
17500 -7.5 18.5 265 42 21 8.1 4.4 | -6.6 20.1 260 31 16 8.0 4.4
17000 -6.4 20.5 265 39 20 7.9 4.3 | -5.5 22.1 255 29 15 8.1 4.4
16500 -5.3 22.5 260 37 19 8.8 4.8 | -4.3 24.3 255 27 14 9.1 5.0
16000 -4.0 24.8 265 34 18 8.9 4.9 | -3.0 26.6 255 25 13 9.1 5.0
15500 -2.7 27.1 265 32 16 8.6 4.7 | -1.0 30.2 255 22 11 8.6 4.7
15000 -1.0 30.2 265 27 14 8.0 4.4 | 0.3 32.5 255 20 10 8.7 4.8
14500 0.1 32.2 265 24 12 8.2 4.5 | 1.6 34.9 255 18 9 8.6 4.7
14000 1.4 34.5 265 22 11 8.3 4.6 | 2.8 37.0 260 15 8 8.6 4.7
13500 2.6 36.7 270 19 10 8.6 4.7 | 4.1 39.4 260 13 7 8.3 4.5
13000 3.9 39.0 270 17 9 8.9 4.9 | 5.2 41.4 260 10 5 8.0 4.4
12500 5.2 41.4 275 14 7 8.8 4.8 | 6.4 43.5 265 8 4 8.0 4.4
12000 6.5 43.7 275 12 6 8.7 4.8 | 7.6 45.7 270 6 3 8.2 4.5
11500 7.8 46.0 285 9 5 8.7 4.8 | 8.8 47.8 290 4 2 8.5 4.7
11000 9.1 48.4 285 8 4 8.5 4.7 | 10.2 50.4 300 4 2 9.3 5.1
10500 10.4 50.7 290 8 4 4.0 2.2 | 11.6 52.9 310 4 2 5.0 2.7
10250 10.5 50.9 290 8 4 6.0 3.3 | 11.8 53.2 315 4 2 6.4 3.5
10000 11.4 52.5 290 8 4 13.6 7.4 | 12.7 54.9 315 4 2 13.2 7.2
9750 12.3 54.1 290 8 4 11.8 6.5 | 13.6 56.5 315 4 2 11.8 6.4
9500 13.2 55.8 290 8 4 11.3 6.2 | 14.4 57.9 320 4 2 10.7 5.9
9250 13.9 57.0 290 7 4 9.4 5.2 | 15.1 59.2 320 4 2 8.7 4.8
9000 14.6 58.3 290 7 4 9.9 5.4 | 15.8 60.4 320 4 2 9.9 5.4
8750 15.4 59.7 290 7 4 10.5 5.8 | 16.6 61.9 320 4 2 10.8 5.9
8500 16.2 61.2 290 7 4 10.3 5.6 | 17.4 63.3 320 4 2 10.3 5.6
8250 16.9 62.4 295 7 4 10.4 5.7 | 18.1 64.6 325 4 2 9.9 5.4
8000 17.7 63.9 295 7 4 10.0 5.5 | 18.9 66.0 325 4 2 10.0 5.5
7750 18.4 65.1 295 7 4 9.5 5.2 | 19.6 67.3 325 4 2 10.2 5.6
7500 19.1 66.4 295 7 4 9.7 5.3 | 20.4 68.7 325 4 2 10.0 5.5
7250 19.9 67.8 295 7 4 9.7 5.3 | 21.1 70.0 325 4 2 9.9 5.4
7000 20.6 69.1 295 7 4 10.0 5.5 | 21.9 71.4 325 4 2 9.9 5.4
6750 21.4 70.5 295 7 4 11.0 6.0 | 22.6 72.7 325 4 2 9.8 5.4
6500 22.2 72.0 295 7 4 10.9 6.0 | 23.4 74.1 330 4 2 10.4 5.7
6250 23.0 73.4 295 7 3 11.0 6.1 | 24.2 75.6 330 4 2 11.2 6.1
6000 23.8 74.8 295 7 3 9.2 5.1 | 25.0 77.0 330 4 2 9.9 5.4
5750 24.6 76.3 295 7 3 15.1 8.3 | 25.7 78.3 330 4 2 12.5 6.8
5500 26.3 79.3 295 6 3 31.6 17.3 | 27.0 80.6 330 4 2 21.2 11.6
________________________________________________________________________________
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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