Soaring Guidance
Issued by NWS Denver/Boulder, CO
Issued by NWS Denver/Boulder, CO
145
UXUS97 KBOU 240147
SRGBOU
Soaring Forecast
National Weather Service Denver/Boulder, Colorado
1946 MDT Monday, September 23, 2024
This forecast is for Tuesday, September 24, 2024:
If the trigger temperature of 67.1 F/19.5 C is reached...then
Thermal Soaring Index....................... Good
Maximum rate of lift........................ 768 ft/min (3.9 m/s)
Maximum height of thermals.................. 14821 ft MSL (9561 ft AGL)
Forecast maximum temperature................... 78.0 F/26.0 C
Time of trigger temperature.................... 1045 MDT
Time of overdevelopment........................ None
Middle/high clouds during soaring window....... None
Surface winds during soaring window............ 20 mph or less
Height of the -3 thermal index................. 11359 ft MSL (6099 ft AGL)
Thermal soaring outlook for Wednesday 09/25.... Good
Wave Soaring Index............................. Poor
Wave Soaring Index trend (to 1800 MDT)......... Becoming poor
Height of stable layer (12-18K ft MSL)......... None
Weak PVA/NVA (through 1800 MDT)................ Weak NVA
Potential height of wave....................... 21031 ft MSL (15771 ft AGL)
Wave soaring outlook for Wednesday 09/25....... Poor
Remarks...
Sunrise/Sunset.................... 06:49:51 / 18:52:39 MDT
Total possible sunshine........... 12 hr 2 min 48 sec (722 min 48 sec)
Altitude of sun at 12:51:15 MDT... 49.30 degrees
Upper air data from numerical model forecast valid on 09/24/2024 at 0600 MDT
Freezing level.................. 13273 ft MSL (8013 ft AGL)
Convective condensation level... 18320 ft MSL (13060 ft AGL)
Lifted condensation level....... 15965 ft MSL (10705 ft AGL)
Lifted index.................... +6.1
K index......................... +12.8
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 -61.9 -79.4 010 46 24 1.6 0.9 M M M M M
45000 -59.3 -74.7 015 64 33 1.7 0.9 M M M M M
40000 -56.4 -69.5 020 80 41 7.3 4.0 M M M M M
38000 -52.2 -62.0 025 76 39 6.9 3.8 M M M M M
36000 -48.1 -54.6 030 73 37 6.9 3.8 M M M M M
34000 -43.1 -45.6 025 65 34 8.8 4.8 M M M M M
32000 -37.8 -36.0 015 58 30 8.8 4.9 M M M M M
30000 -31.7 -25.1 010 55 28 9.1 5.0 44.6 112.3 14.4 M M
29000 -29.0 -20.2 005 54 28 9.1 5.0 44.4 111.9 14.4 M M
28000 -26.3 -15.3 005 54 28 8.9 4.9 44.3 111.7 14.5 M M
27000 -23.8 -10.8 005 53 27 8.3 4.6 43.7 110.6 14.2 M M
26000 -21.3 -6.3 005 52 27 8.4 4.6 43.1 109.6 13.9 M M
25000 -18.8 -1.8 010 51 26 8.5 4.7 42.7 108.8 13.7 M M
24000 -16.7 1.9 010 50 26 6.4 3.5 41.6 106.9 13.0 M M
23000 -14.8 5.4 010 49 25 6.4 3.5 40.4 104.6 12.0 M M
22000 -13.0 8.6 005 47 24 6.5 3.6 39.2 102.6 11.1 M M
21000 -11.3 11.7 005 43 22 5.3 2.9 37.7 99.9 10.0 M M
20000 -9.8 14.4 360 38 19 5.3 2.9 36.1 97.0 8.7 M M
19500 -9.0 15.8 355 35 18 5.3 2.9 35.4 95.7 8.1 M M
19000 -8.2 17.2 355 33 17 4.4 2.4 34.7 94.4 7.5 M M
18500 -7.7 18.1 350 31 16 3.4 1.9 33.5 92.4 6.5 M M
18000 -7.3 18.9 345 30 15 3.3 1.8 32.4 90.4 5.5 M M
17500 -6.8 19.8 340 29 15 3.5 1.9 31.3 88.4 4.6 M M
17000 -6.3 20.7 335 29 15 3.5 1.9 30.3 86.5 3.7 M M
16500 -5.7 21.7 335 29 15 3.8 2.1 29.2 84.6 2.8 M M
16000 -5.2 22.6 335 29 15 4.1 2.3 28.3 82.9 1.9 M M
15500 -4.6 23.7 335 29 15 4.3 2.4 27.3 81.2 1.0 M M
15000 -3.8 25.2 335 28 14 6.0 3.3 26.6 79.9 0.4 M M
14500 -2.5 27.5 335 27 14 6.6 3.6 25.6 78.2 -0.5 732 3.7
14000 -1.4 29.5 335 25 13 7.4 4.0 25.2 77.4 -0.9 684 3.5
13500 -0.3 31.5 335 24 12 7.5 4.1 24.8 76.7 -1.3 636 3.2
13000 0.9 33.6 330 22 11 7.7 4.2 24.5 76.1 -1.6 587 3.0
12500 2.0 35.6 330 20 10 7.5 4.1 24.2 75.5 -1.9 538 2.7
12000 3.0 37.4 325 18 9 6.1 3.3 23.7 74.6 -2.4 493 2.5
11500 3.9 39.0 320 16 8 6.1 3.4 23.1 73.6 -2.9 451 2.3
11000 4.7 40.5 315 14 7 4.8 2.7 22.4 72.3 -3.6 412 2.1
10500 5.5 41.9 320 12 6 4.3 2.3 21.7 71.0 -4.3 375 1.9
10250 5.7 42.3 320 11 6 2.2 1.2 21.1 70.1 -4.8 360 1.8
10000 6.0 42.8 325 11 6 5.8 3.2 20.6 69.1 -5.4 346 1.8
9750 6.6 43.9 330 10 5 9.4 5.1 20.5 68.9 -5.5 320 1.6
9500 7.2 45.0 345 9 5 7.6 4.2 20.4 68.8 -5.6 294 1.5
9250 7.6 45.7 350 9 5 4.6 2.5 20.2 68.3 -5.9 273 1.4
9000 8.0 46.4 355 9 5 5.9 3.2 19.7 67.5 -6.3 256 1.3
8750 8.6 47.5 360 9 5 10.0 5.5 19.6 67.3 -6.4 230 1.2
8500 9.3 48.7 010 10 5 7.3 4.0 19.6 67.3 -6.5 202 1.0
8250 9.6 49.3 010 10 5 3.8 2.1 19.2 66.6 -6.9 184 0.9
8000 9.9 49.8 015 11 6 4.6 2.5 18.8 65.8 -7.4 168 0.9
7750 10.4 50.7 015 12 6 7.7 4.2 18.5 65.3 -7.7 147 0.7
7500 11.0 51.8 015 12 6 7.3 4.0 18.4 65.1 -7.8 122 0.6
7250 11.4 52.5 015 12 6 5.3 2.9 18.1 64.5 -8.1 102 0.5
7000 11.8 53.2 010 13 6 6.3 3.4 17.8 64.0 -8.5 81 0.4
6750 12.3 54.1 010 12 6 7.2 4.0 17.6 63.6 -8.7 59 0.3
6500 12.8 55.0 005 12 6 4.9 2.7 17.3 63.2 -9.0 36 0.2
6250 13.1 55.6 360 12 6 3.2 1.8 16.8 62.3 -9.5 21 0.1
6000 13.3 55.9 355 11 6 2.7 1.5 16.4 61.4 -9.9 6 0.0
5750 13.4 56.1 350 10 5 -0.9 -0.5 15.7 60.2 -10.6 M M
5500 13.2 55.8 340 7 4 -3.2 -1.8 14.8 58.6 -11.6 M M
* * * * * * Numerical weather prediction model forecast data valid * * * * * *
09/24/2024 at 0900 MDT | 09/24/2024 at 1200 MDT
|
CAPE... 0.0 LI... +7.5 | CAPE... 0.0 LI... +7.9
CINH... -0.3 K Index... +12.3 | CINH... -0.1 K Index... +13.1
|
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 -63.0 -81.4 015 49 25 0.7 0.4 | -64.4 -83.9 020 42 22 0.7 0.4
45000 -61.0 -77.8 020 66 34 3.0 1.7 | -62.1 -79.8 020 58 30 4.0 2.2
40000 -56.1 -69.0 025 69 36 8.1 4.5 | -55.2 -67.4 020 59 30 7.5 4.1
38000 -51.5 -60.7 025 66 34 7.7 4.2 | -50.6 -59.1 020 54 28 7.6 4.2
36000 -46.9 -52.4 030 63 32 7.7 4.2 | -46.1 -51.0 020 50 25 7.5 4.1
34000 -41.3 -42.3 025 54 28 8.4 4.6 | -40.8 -41.4 015 46 24 9.0 4.9
32000 -36.2 -33.2 010 48 25 8.3 4.6 | -35.4 -31.7 010 44 23 8.9 4.9
30000 -30.9 -23.6 005 48 25 8.9 4.9 | -30.4 -22.7 005 44 23 8.3 4.6
29000 -28.3 -18.9 360 49 25 8.9 4.9 | -27.9 -18.2 005 44 23 8.3 4.6
28000 -25.6 -14.1 360 50 26 8.5 4.7 | -25.4 -13.7 005 45 23 8.2 4.5
27000 -23.2 -9.8 360 48 25 7.8 4.3 | -22.7 -8.9 005 43 22 7.3 4.0
26000 -20.9 -5.6 360 46 24 7.8 4.3 | -20.5 -4.9 010 41 21 7.3 4.0
25000 -18.6 -1.5 360 44 23 7.9 4.3 | -18.4 -1.1 010 39 20 7.3 4.0
24000 -16.4 2.5 360 42 22 7.3 4.0 | -16.2 2.8 010 37 19 7.2 3.9
23000 -14.2 6.4 005 41 21 7.3 4.0 | -14.1 6.6 010 36 18 7.2 4.0
22000 -12.0 10.4 005 39 20 7.5 4.1 | -12.0 10.4 005 34 18 7.1 3.9
21000 -10.3 13.5 005 38 20 5.2 2.9 | -10.0 14.0 005 34 17 6.5 3.6
20000 -8.8 16.2 360 38 19 5.3 2.9 | -8.1 17.4 005 33 17 6.6 3.6
19500 -8.0 17.6 360 37 19 5.3 2.9 | -7.1 19.2 360 33 17 6.7 3.7
19000 -7.3 18.9 360 37 19 4.8 2.6 | -6.2 20.8 360 33 17 5.2 2.9
18500 -6.6 20.1 355 36 19 4.5 2.5 | -5.5 22.1 360 32 17 5.0 2.7
18000 -6.0 21.2 355 36 18 4.5 2.5 | -4.8 23.4 360 32 16 4.9 2.7
17500 -5.4 22.3 355 35 18 3.9 2.1 | -4.2 24.4 355 31 16 4.1 2.2
17000 -4.9 23.2 350 34 17 3.9 2.2 | -3.6 25.5 355 30 15 4.2 2.3
16500 -4.1 24.6 345 33 17 2.7 1.5 | -3.1 26.4 350 29 15 3.1 1.7
16000 -3.7 25.3 345 31 16 2.8 1.6 | -2.7 27.1 350 28 15 2.9 1.6
15500 -3.3 26.1 340 30 16 3.0 1.7 | -2.3 27.9 345 28 14 2.9 1.6
15000 -2.8 27.0 340 29 15 3.1 1.7 | -1.9 28.6 345 26 14 2.8 1.5
14500 -2.4 27.7 335 27 14 4.0 2.2 | -1.5 29.3 340 25 13 2.9 1.6
14000 -1.6 29.1 335 25 13 5.0 2.7 | -0.9 30.4 335 24 12 4.8 2.7
13500 -0.9 30.4 335 23 12 5.4 3.0 | 0.1 32.2 330 22 11 5.2 2.9
13000 0.0 32.0 335 21 11 6.6 3.6 | 1.0 33.8 330 20 10 5.8 3.2
12500 1.0 33.8 340 20 10 6.7 3.7 | 1.8 35.2 325 18 9 6.1 3.3
12000 2.1 35.8 340 18 9 7.6 4.2 | 2.8 37.0 325 16 8 6.6 3.6
11500 3.2 37.8 345 16 8 7.5 4.1 | 3.7 38.7 330 15 8 6.8 3.7
11000 4.3 39.7 345 14 7 6.8 3.7 | 4.9 40.8 330 13 7 7.4 4.1
10500 5.3 41.5 340 12 6 5.7 3.1 | 6.0 42.8 335 12 6 4.5 2.5
10250 5.6 42.1 340 11 6 2.3 1.3 | 6.2 43.2 340 11 6 2.8 1.5
10000 5.8 42.4 340 11 6 6.1 3.4 | 6.6 43.9 340 11 6 9.4 5.1
9750 6.5 43.7 335 9 5 10.4 5.7 | 7.5 45.5 340 10 5 12.4 6.8
9500 7.2 45.0 330 8 4 7.4 4.1 | 8.3 46.9 340 8 4 8.7 4.8
9250 7.6 45.7 330 7 4 3.2 1.8 | 8.7 47.7 340 8 4 3.5 1.9
9000 7.8 46.0 330 7 4 4.4 2.4 | 9.1 48.4 340 7 4 7.3 4.0
8750 8.3 46.9 330 6 3 7.8 4.3 | 9.8 49.6 340 6 3 11.7 6.4
8500 8.8 47.8 335 5 2 6.2 3.4 | 10.6 51.1 345 5 2 7.3 4.0
8250 9.2 48.6 340 4 2 4.2 2.3 | 10.9 51.6 345 4 2 3.6 2.0
8000 9.5 49.1 345 3 2 5.5 3.0 | 11.3 52.3 350 3 2 6.8 3.7
7750 10.0 50.0 350 3 2 8.6 4.7 | 11.9 53.4 355 3 1 10.5 5.8
7500 10.7 51.3 355 3 1 7.4 4.1 | 12.7 54.9 005 2 1 9.1 5.0
7250 11.1 52.0 355 3 1 4.9 2.7 | 13.2 55.8 005 2 1 6.3 3.5
7000 11.5 52.7 355 2 1 6.2 3.4 | 13.8 56.8 005 2 1 9.8 5.4
6750 12.0 53.6 345 2 1 8.8 4.8 | 14.7 58.5 015 2 1 14.0 7.7
6500 12.7 54.9 320 2 1 7.8 4.3 | 15.7 60.3 020 2 1 11.5 6.3
6250 13.2 55.8 300 2 1 6.8 3.7 | 16.4 61.5 020 2 1 10.8 5.9
6000 13.7 56.7 285 2 1 4.2 2.3 | 17.2 63.0 025 1 1 7.4 4.1
5750 13.9 57.0 275 2 1 5.7 3.1 | 17.7 63.9 025 1 1 11.5 6.3
5500 14.7 58.5 265 2 1 17.9 9.8 | 19.3 66.7 025 1 1 29.9 16.4
09/24/2024 at 1500 MDT | 09/24/2024 at 1800 MDT
|
CAPE... 0.0 LI... +6.2 | CAPE... 0.0 LI... +4.6
CINH... -0.1 K Index... +14.6 | CINH... -0.1 K Index... +14.7
|
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 -65.1 -85.2 015 32 17 1.8 1.0 | -65.2 -85.4 010 29 15 2.4 1.3
45000 -61.7 -79.1 020 45 23 3.7 2.0 | -60.8 -77.4 020 39 20 3.8 2.1
40000 -55.2 -67.4 020 50 26 7.6 4.2 | -54.5 -66.1 025 46 24 7.1 3.9
38000 -50.5 -58.9 020 48 25 7.7 4.2 | -50.2 -58.4 020 44 23 7.2 3.9
36000 -45.9 -50.6 015 46 24 7.6 4.2 | -45.9 -50.6 015 43 22 7.0 3.8
34000 -40.7 -41.3 015 44 23 8.8 4.8 | -40.8 -41.4 015 41 21 8.6 4.7
32000 -35.4 -31.7 015 43 22 8.7 4.8 | -35.7 -32.3 015 39 20 8.5 4.7
30000 -30.2 -22.4 015 42 22 8.7 4.8 | -30.4 -22.7 015 39 20 9.0 4.9
29000 -27.6 -17.7 015 43 22 8.7 4.8 | -27.0 -16.6 015 40 21 9.0 4.9
28000 -24.4 -11.9 015 42 22 7.6 4.2 | -24.4 -11.9 015 40 21 7.8 4.3
27000 -22.2 -8.0 015 41 21 7.5 4.1 | -22.0 -7.6 020 39 20 7.9 4.3
26000 -20.0 -4.0 015 39 20 7.5 4.1 | -19.7 -3.5 020 38 20 7.9 4.3
25000 -17.7 0.1 015 38 19 7.4 4.1 | -17.3 0.9 020 37 19 7.6 4.2
24000 -15.7 3.7 015 35 18 6.9 3.8 | -15.2 4.6 020 34 17 6.9 3.8
23000 -13.7 7.3 010 33 17 6.9 3.8 | -13.2 8.2 020 30 15 7.0 3.8
22000 -11.6 11.1 010 30 16 6.9 3.8 | -11.1 12.0 020 26 13 6.8 3.7
21000 -9.7 14.5 010 29 15 6.9 3.8 | -9.2 15.4 020 25 13 6.5 3.6
20000 -7.7 18.1 005 29 15 6.9 3.8 | -7.2 19.0 015 25 13 6.6 3.6
19500 -6.7 19.9 005 28 14 7.1 3.9 | -6.3 20.7 015 25 13 6.5 3.6
19000 -5.8 21.6 005 28 14 5.4 3.0 | -5.3 22.5 010 25 13 7.0 3.8
18500 -5.0 23.0 005 28 14 5.4 3.0 | -4.3 24.3 010 26 13 6.9 3.8
18000 -4.3 24.3 360 27 14 5.4 2.9 | -3.2 26.2 010 26 13 6.3 3.5
17500 -3.6 25.5 360 27 14 5.1 2.8 | -2.5 27.5 010 26 13 5.1 2.8
17000 -2.9 26.8 355 27 14 5.3 2.9 | -1.7 28.9 005 26 13 5.3 2.9
16500 -2.3 27.9 355 27 14 3.7 2.0 | -1.1 30.0 360 26 13 4.0 2.2
16000 -1.8 28.8 350 27 14 3.7 2.0 | -0.5 31.1 355 25 13 4.1 2.2
15500 -1.4 29.5 345 26 14 4.0 2.2 | 0.0 32.0 350 25 13 4.3 2.3
15000 -0.8 30.6 340 25 13 4.3 2.4 | 0.6 33.1 340 24 12 4.5 2.4
14500 -0.2 31.6 335 24 13 4.6 2.5 | 1.2 34.2 335 23 12 5.0 2.7
14000 0.6 33.1 330 24 12 6.1 3.4 | 2.1 35.8 330 22 12 6.8 3.7
13500 1.5 34.7 325 23 12 6.0 3.3 | 3.6 38.5 325 22 12 7.8 4.3
13000 2.9 37.2 320 22 11 7.1 3.9 | 4.8 40.6 325 21 11 8.4 4.6
12500 4.0 39.2 320 21 11 7.0 3.9 | 6.1 43.0 320 20 10 7.6 4.2
12000 5.0 41.0 320 19 10 6.8 3.8 | 7.1 44.8 325 18 9 6.6 3.6
11500 6.0 42.8 320 16 8 6.8 3.7 | 8.0 46.4 330 17 9 6.3 3.5
11000 7.0 44.6 325 14 7 6.6 3.6 | 8.9 48.0 330 15 8 5.6 3.1
10500 8.0 46.4 330 12 6 2.8 1.5 | 9.8 49.6 335 14 7 3.1 1.7
10250 8.0 46.4 330 12 6 2.5 1.4 | 9.9 49.8 335 14 7 3.1 1.7
10000 8.6 47.5 335 11 6 9.9 5.4 | 10.4 50.7 340 12 6 7.8 4.3
9750 9.4 48.9 340 10 5 11.4 6.3 | 11.0 51.8 345 11 6 8.4 4.6
9500 10.1 50.2 350 9 4 7.9 4.4 | 11.6 52.9 350 9 5 6.3 3.5
9250 10.5 50.9 350 8 4 3.4 1.9 | 11.9 53.4 350 8 4 3.4 1.9
9000 10.9 51.6 355 8 4 8.6 4.7 | 12.3 54.1 350 7 3 7.3 4.0
8750 11.8 53.2 360 7 4 13.0 7.1 | 13.0 55.4 355 5 2 10.6 5.8
8500 12.6 54.7 005 6 3 8.9 4.9 | 13.7 56.7 005 3 2 7.8 4.3
8250 13.1 55.6 005 6 3 5.5 3.0 | 14.2 57.6 010 3 1 5.1 2.8
8000 13.6 56.5 005 6 3 9.7 5.3 | 14.6 58.3 010 3 1 8.9 4.9
7750 14.5 58.1 010 6 3 13.7 7.5 | 15.5 59.9 015 2 1 13.1 7.2
7500 15.4 59.7 010 6 3 9.8 5.4 | 16.4 61.5 020 2 1 9.9 5.5
7250 16.0 60.8 010 6 3 6.2 3.4 | 17.0 62.6 020 2 1 7.0 3.9
7000 16.5 61.7 010 6 3 10.5 5.7 | 17.6 63.7 025 2 1 9.6 5.3
6750 17.5 63.5 015 6 3 14.4 7.9 | 18.4 65.1 025 2 1 12.4 6.8
6500 18.5 65.3 015 6 3 11.2 6.1 | 19.3 66.7 030 2 1 10.7 5.8
6250 19.3 66.7 015 6 3 10.9 6.0 | 20.0 68.0 030 2 1 10.2 5.6
6000 20.0 68.0 020 6 3 7.0 3.8 | 20.8 69.4 030 2 1 7.4 4.1
5750 20.5 68.9 015 6 3 11.2 6.1 | 21.2 70.2 030 2 1 6.8 3.7
5500 22.1 71.8 020 6 3 31.1 17.0 | 22.0 71.6 030 2 1 15.5 8.5
________________________________________________________________________________
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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