Soaring Guidance
Issued by NWS Grand Junction, CO
Issued by NWS Grand Junction, CO
292
UXUS97 KGJT 021307
SRGGJT
Soaring Forecast
National Weather Service Grand Junction, Colorado
707 AM MDT Tuesday, July 2, 2024
This forecast is for Tuesday, July 2, 2024:
If the trigger temperature of 75.1 F/23.9 C is reached...then
Thermal Soaring Index....................... Excellent
Maximum rate of lift........................ 1055 ft/min (5.4 m/s)
Maximum height of thermals.................. 17253 ft MSL (12414 ft AGL)
Forecast maximum temperature................... 89.0 F/32.1 C
Time of trigger temperature.................... 0945 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................. 13979 ft MSL (9140 ft AGL)
Thermal soaring outlook for Wednesday 07/03.... Excellent
Wave Soaring Index............................. Not available
Remarks...
Sunrise/Sunset.................... 05:52:49 / 20:43:56 MDT
Total possible sunshine........... 14 hr 51 min 7 sec (891 min 7 sec)
Altitude of sun at 13:18:22 MDT... 73.37 degrees
Upper air data from rawinsonde observation taken on 07/02/2024 at 0600 MDT
Freezing level.................. 14463 ft MSL (9624 ft AGL)
Convective condensation level... 12613 ft MSL (7774 ft AGL)
Lifted condensation level....... 14679 ft MSL (9840 ft AGL)
Lifted index.................... +0.2
K index......................... +20.1
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 -62.5 -80.5 290 49 25 5.8 3.2 89.0 192.2 33.4 M M
45000 -56.1 -69.0 270 50 26 6.6 3.6 75.4 167.7 27.2 M M
40000 -46.1 -51.0 255 55 28 4.9 2.7 67.1 152.8 23.7 M M
38000 -43.1 -45.6 250 58 30 5.5 3.0 62.9 145.3 21.4 M M
36000 -39.8 -39.6 240 62 32 5.4 3.0 59.2 138.6 19.4 M M
34000 -36.1 -33.0 245 59 30 6.2 3.4 56.2 133.2 17.7 M M
32000 -32.4 -26.3 255 59 30 5.6 3.1 53.3 127.9 16.0 M M
30000 -27.4 -17.3 260 51 26 7.0 3.9 51.1 124.0 14.8 M M
29000 -27.8 -18.0 270 58 30 5.2 2.8 46.8 116.3 11.6 M M
28000 -25.3 -13.5 270 59 30 9.4 5.2 46.3 115.3 11.3 M M
27000 -22.5 -8.5 265 60 31 9.4 5.2 46.2 115.1 11.4 M M
26000 -19.8 -3.6 270 60 31 8.7 4.8 45.8 114.5 11.3 M M
25000 -17.2 1.0 270 61 31 8.6 4.7 45.4 113.8 11.1 M M
24000 -14.6 5.7 265 61 31 7.8 4.3 45.0 113.1 10.9 M M
23000 -12.4 9.7 270 63 32 5.2 2.8 44.2 111.5 10.3 M M
22000 -11.5 11.3 255 53 27 -1.3 -0.7 41.7 107.1 8.4 M M
21000 -12.3 9.9 260 51 26 -8.1 -4.4 37.3 99.2 4.7 M M
20000 -12.4 9.7 255 44 22 6.9 3.8 33.9 93.1 1.8 M M
19500 -11.6 11.1 255 43 22 5.8 3.2 33.2 91.8 1.1 M M
19000 -10.8 12.6 255 41 21 7.3 4.0 32.6 90.6 0.4 M M
18500 -9.4 15.1 260 41 21 10.0 5.5 32.5 90.4 0.3 M M
18000 -8.0 17.6 260 42 22 9.8 5.4 32.5 90.5 0.3 M M
17500 -6.5 20.3 260 37 19 8.6 4.7 32.5 90.5 0.3 M M
17000 -5.5 22.1 265 40 21 7.3 4.0 32.1 89.8 -0.1 1042 5.3
16500 -4.0 24.8 260 33 17 7.3 4.0 31.5 88.6 -0.8 974 4.9
16000 -2.9 26.8 255 27 14 7.4 4.0 31.0 87.9 -1.2 928 4.7
15500 -1.9 28.6 250 24 12 7.5 4.1 30.6 87.1 -1.7 883 4.5
15000 -0.9 30.4 245 20 10 6.7 3.7 30.2 86.4 -2.1 838 4.3
14500 0.1 32.2 270 16 8 6.5 3.5 29.7 85.4 -2.6 793 4.0
14000 1.1 34.0 290 18 9 6.4 3.5 29.1 84.4 -3.1 748 3.8
13500 2.1 35.8 300 20 10 6.2 3.4 28.6 83.5 -3.5 703 3.6
13000 2.9 37.2 320 16 8 5.9 3.3 28.0 82.4 -4.2 664 3.4
12500 3.7 38.7 310 10 5 6.1 3.3 27.4 81.2 -4.9 626 3.2
12000 4.8 40.6 340 5 3 8.4 4.6 27.0 80.6 -5.3 579 2.9
11500 6.0 42.8 355 8 4 8.3 4.5 26.7 80.1 -5.5 527 2.7
11000 7.3 45.1 020 10 5 8.2 4.5 26.5 79.7 -5.7 474 2.4
10500 8.5 47.3 030 12 6 8.1 4.4 26.3 79.3 -6.0 422 2.1
10250 9.1 48.4 030 14 7 6.3 3.5 26.1 78.9 -6.1 397 2.0
10000 9.6 49.3 030 17 9 6.7 3.7 25.8 78.4 -6.4 376 1.9
9750 10.1 50.2 030 17 9 8.0 4.4 25.6 78.1 -6.6 353 1.8
9500 10.7 51.3 025 14 7 7.6 4.2 25.4 77.8 -6.9 329 1.7
9250 11.2 52.2 020 12 6 7.8 4.3 25.3 77.5 -7.1 306 1.6
9000 11.7 53.1 015 10 5 7.6 4.2 25.1 77.2 -7.3 282 1.4
8750 12.3 54.1 010 9 5 9.1 5.0 25.0 77.0 -7.5 258 1.3
8500 13.0 55.4 005 9 5 10.6 5.8 25.0 77.0 -7.5 228 1.2
8250 13.8 56.8 355 8 4 9.8 5.4 25.1 77.1 -7.5 199 1.0
8000 14.4 57.9 345 8 4 8.4 4.6 25.0 77.0 -7.6 172 0.9
7750 14.9 58.8 345 9 5 7.6 4.2 24.9 76.8 -7.8 149 0.8
7500 15.4 59.7 340 9 4 7.9 4.4 24.7 76.5 -8.0 126 0.6
7250 16.0 60.8 330 8 4 7.8 4.3 24.6 76.2 -8.3 104 0.5
7000 16.5 61.7 320 8 4 8.4 4.6 24.4 76.0 -8.5 81 0.4
6750 17.1 62.8 320 8 4 9.0 4.9 24.4 75.8 -8.7 56 0.3
6500 17.7 63.9 340 8 4 9.7 5.3 24.3 75.8 -8.8 29 0.1
6250 18.3 64.9 345 7 3 7.4 4.1 24.3 75.7 -8.9 3 0.0
6000 18.7 65.7 355 5 3 5.9 3.2 24.0 75.2 -9.2 M M
5750 19.1 66.4 005 4 2 3.0 1.7 23.7 74.6 -9.6 M M
5500 19.0 66.2 010 3 2 -2.0 -1.1 22.9 73.2 -10.4 M M
5250 18.9 66.0 020 1 0 -0.1 -0.1 22.1 71.7 -11.4 M M
5000 18.9 66.0 200 2 1 2.2 1.2 21.4 70.6 -12.1 M M
* * * * * * Numerical weather prediction model forecast data valid * * * * * *
07/02/2024 at 0900 MDT | 07/02/2024 at 1200 MDT
|
CAPE... +2.2 LI... +1.7 | CAPE... 0.0 LI... +4.2
CINH... -15.5 K Index... +16.9 | CINH... -0.2 K Index... +2.3
|
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 -61.0 -77.8 275 30 16 3.2 1.8 | -60.9 -77.6 265 29 15 3.0 1.6
45000 -54.6 -66.3 275 39 20 6.3 3.5 | -54.7 -66.5 265 37 19 6.4 3.5
40000 -45.0 -49.0 260 49 25 4.7 2.6 | -45.1 -49.2 255 49 25 4.5 2.5
38000 -42.1 -43.8 255 52 27 4.8 2.6 | -42.3 -44.1 255 52 27 4.6 2.5
36000 -39.3 -38.7 250 56 29 4.8 2.6 | -39.6 -39.3 255 56 29 4.7 2.6
34000 -36.7 -34.1 255 54 28 4.2 2.3 | -37.4 -35.3 255 53 27 3.6 2.0
32000 -34.1 -29.4 260 51 26 4.3 2.3 | -35.2 -31.4 260 50 26 3.6 2.0
30000 -30.4 -22.7 270 51 26 6.8 3.7 | -31.5 -24.7 265 48 25 7.0 3.9
29000 -28.4 -19.1 270 52 27 6.8 3.7 | -29.4 -20.9 270 47 24 7.0 3.9
28000 -26.4 -15.5 275 52 27 7.1 3.9 | -27.3 -17.1 275 47 24 7.6 4.2
27000 -23.8 -10.8 275 53 27 8.7 4.8 | -24.6 -12.3 275 46 24 8.9 4.9
26000 -21.2 -6.2 275 53 27 8.7 4.7 | -21.9 -7.4 275 46 24 8.9 4.9
25000 -18.0 -0.4 280 53 27 8.3 4.6 | -18.6 -1.5 280 45 23 8.6 4.7
24000 -16.0 3.2 280 51 26 6.2 3.4 | -16.2 2.8 280 44 23 7.7 4.3
23000 -14.1 6.6 280 48 25 6.3 3.4 | -13.9 7.0 280 43 22 7.7 4.3
22000 -12.3 9.9 280 46 24 5.7 3.1 | -11.6 11.1 285 41 21 6.8 3.7
21000 -11.0 12.2 280 45 23 4.0 2.2 | -10.0 14.0 285 39 20 5.1 2.8
20000 -9.9 14.2 275 44 22 4.1 2.2 | -8.4 16.9 285 37 19 5.1 2.8
19500 -9.3 15.3 275 43 22 4.1 2.2 | -7.7 18.1 285 36 18 5.2 2.9
19000 -8.7 16.3 275 43 22 5.1 2.8 | -6.9 19.6 285 35 18 4.6 2.5
18500 -7.9 17.8 270 42 22 5.3 2.9 | -6.2 20.8 280 34 17 4.7 2.6
18000 -7.2 19.0 270 42 22 6.0 3.3 | -5.5 22.1 280 33 17 4.9 2.7
17500 -6.2 20.8 270 42 21 7.4 4.1 | -4.8 23.4 280 32 17 5.3 2.9
17000 -5.2 22.6 270 41 21 7.5 4.1 | -4.0 24.8 280 32 16 5.4 3.0
16500 -4.1 24.6 270 41 21 7.6 4.2 | -3.2 26.2 275 31 16 5.3 2.9
16000 -3.0 26.6 270 39 20 7.7 4.2 | -2.4 27.7 275 31 16 5.5 3.0
15500 -1.9 28.6 270 38 20 7.2 4.0 | -1.6 29.1 275 30 16 6.5 3.5
15000 -0.9 30.4 275 36 18 7.0 3.9 | -0.7 30.7 275 29 15 6.8 3.8
14500 0.1 32.2 275 34 17 7.0 3.8 | 0.3 32.5 275 28 14 7.0 3.9
14000 1.2 34.2 275 31 16 6.8 3.7 | 1.4 34.5 275 26 14 7.3 4.0
13500 2.2 36.0 280 29 15 6.8 3.7 | 2.5 36.5 280 24 13 7.3 4.0
13000 3.2 37.8 280 26 14 6.9 3.8 | 3.5 38.3 280 22 11 7.1 3.9
12500 4.3 39.7 285 24 12 7.0 3.8 | 4.5 40.1 280 20 10 7.1 3.9
12000 5.3 41.5 290 21 11 6.8 3.7 | 5.6 42.1 285 18 9 7.8 4.3
11500 6.4 43.5 290 19 10 6.7 3.7 | 6.8 44.2 285 16 8 7.8 4.3
11000 7.4 45.3 295 17 9 8.0 4.4 | 7.9 46.2 285 15 7 7.8 4.3
10500 8.6 47.5 295 15 7 8.4 4.6 | 9.0 48.2 290 13 7 7.0 3.8
10250 9.1 48.4 295 14 7 6.0 3.3 | 9.5 49.1 290 12 6 6.7 3.7
10000 9.5 49.1 295 13 7 6.1 3.3 | 10.1 50.2 290 12 6 9.0 4.9
9750 10.0 50.0 295 11 6 8.5 4.7 | 10.8 51.4 290 11 6 9.7 5.3
9500 10.6 51.1 295 10 5 8.3 4.5 | 11.4 52.5 295 10 5 9.6 5.3
9250 11.1 52.0 290 8 4 6.6 3.6 | 12.1 53.8 295 10 5 7.8 4.3
9000 11.5 52.7 290 7 4 6.1 3.4 | 12.6 54.7 295 10 5 8.6 4.7
8750 12.6 54.7 295 4 2 7.2 3.9 | 13.4 56.1 295 9 5 10.8 5.9
8500 13.0 55.4 300 3 2 5.8 3.2 | 14.1 57.4 295 9 5 10.0 5.5
8250 13.4 56.1 320 2 1 5.6 3.1 | 15.3 59.5 300 9 5 8.6 4.7
8000 13.9 57.0 350 2 1 7.5 4.1 | 16.1 61.0 300 8 4 12.3 6.8
7750 14.5 58.1 015 2 1 6.9 3.8 | 17.0 62.6 300 8 4 10.6 5.8
7500 14.9 58.8 025 3 2 5.2 2.9 | 17.6 63.7 300 8 4 7.4 4.1
7250 15.3 59.5 035 4 2 5.1 2.8 | 18.2 64.8 300 8 4 7.8 4.3
7000 15.8 60.4 035 4 2 9.5 5.2 | 18.9 66.0 300 8 4 13.7 7.5
6750 16.6 61.9 030 4 2 10.1 5.5 | 20.0 68.0 300 7 4 12.7 7.0
6500 17.2 63.0 035 4 2 8.0 4.4 | 20.8 69.4 300 7 4 9.1 5.0
6250 17.8 64.0 035 4 2 7.9 4.3 | 21.5 70.7 300 7 4 9.0 5.0
6000 18.4 65.1 035 4 2 10.6 5.8 | 22.2 72.0 300 7 4 13.3 7.3
5750 19.4 66.9 030 3 2 19.4 10.6 | 23.7 74.7 300 6 3 28.1 15.4
5500 20.9 69.6 035 4 2 15.0 8.2 | 25.9 78.6 305 6 3 23.5 12.9
5250 M M M M M M M | M M M M M M M
5000 M M M M M M M | M M M M M M M
07/02/2024 at 1500 MDT | 07/02/2024 at 1800 MDT
|
CAPE... 0.0 LI... +5.7 | CAPE... 0.0 LI... +5.3
CINH... -0.2 K Index... +1.9 | CINH... -0.1 K Index... +0.6
|
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 -76.9 265 32 16 2.8 1.6 | -60.0 -76.0 270 35 18 2.8 1.5
45000 -54.7 -66.5 255 41 21 5.8 3.2 | -54.5 -66.1 260 46 24 5.5 3.0
40000 -46.0 -50.8 250 55 28 4.2 2.3 | -46.2 -51.2 255 57 30 3.6 2.0
38000 -43.4 -46.1 255 55 28 4.2 2.3 | -44.0 -47.2 255 57 29 3.6 2.0
36000 -40.9 -41.6 255 55 29 4.2 2.3 | -41.9 -43.4 255 57 29 3.5 1.9
34000 -38.4 -37.1 255 53 27 4.2 2.3 | -39.4 -38.9 255 56 29 4.3 2.4
32000 -35.9 -32.6 260 50 26 4.1 2.2 | -36.8 -34.2 255 54 28 4.2 2.3
30000 -32.0 -25.6 265 48 24 7.1 3.9 | -32.6 -26.7 255 48 25 7.8 4.3
29000 -29.9 -21.8 265 46 24 7.1 3.9 | -30.2 -22.4 260 45 23 7.8 4.3
28000 -27.8 -18.0 270 45 23 7.9 4.3 | -27.9 -18.2 260 42 22 8.1 4.5
27000 -25.1 -13.2 270 43 22 9.0 5.0 | -25.3 -13.5 260 39 20 8.6 4.7
26000 -22.4 -8.3 275 41 21 9.0 5.0 | -22.1 -7.8 265 35 18 8.6 4.7
25000 -19.0 -2.2 275 39 20 8.7 4.8 | -19.5 -3.1 270 32 16 8.5 4.7
24000 -16.5 2.3 280 37 19 8.2 4.5 | -17.0 1.4 270 31 16 8.3 4.6
23000 -14.0 6.8 280 35 18 8.2 4.5 | -14.5 5.9 270 30 15 8.3 4.6
22000 -11.5 11.3 280 34 17 7.3 4.0 | -12.0 10.4 275 29 15 7.6 4.2
21000 -9.6 14.7 280 32 16 6.4 3.5 | -9.9 14.2 275 27 14 6.9 3.8
20000 -7.7 18.1 280 29 15 6.4 3.5 | -7.9 17.8 275 25 13 6.9 3.8
19500 -6.7 19.9 280 28 15 6.5 3.6 | -6.8 19.8 275 24 13 6.9 3.8
19000 -5.8 21.6 280 27 14 5.2 2.8 | -5.9 21.4 270 23 12 5.5 3.0
18500 -5.0 23.0 280 26 13 5.3 2.9 | -5.1 22.8 270 22 11 5.6 3.1
18000 -4.2 24.4 275 25 13 4.9 2.7 | -4.2 24.4 270 20 10 5.5 3.0
17500 -3.6 25.5 275 24 12 4.6 2.5 | -3.4 25.9 270 19 10 5.4 3.0
17000 -2.9 26.8 275 22 12 4.6 2.5 | -2.6 27.3 270 17 9 5.4 3.0
16500 -2.2 28.0 275 21 11 5.2 2.9 | -1.8 28.8 270 16 8 6.4 3.5
16000 -1.5 29.3 275 20 10 5.2 2.9 | -0.9 30.4 270 15 7 6.3 3.5
15500 -0.7 30.7 275 18 9 6.4 3.5 | 0.1 32.2 270 13 7 7.2 4.0
15000 0.3 32.5 275 17 9 6.7 3.7 | 1.2 34.2 270 12 6 7.5 4.1
14500 1.2 34.2 275 16 8 7.3 4.0 | 2.3 36.1 270 11 6 8.0 4.4
14000 2.4 36.3 275 15 8 8.0 4.4 | 3.5 38.3 270 11 6 8.7 4.8
13500 3.5 38.3 280 14 7 8.2 4.5 | 4.8 40.6 270 10 5 8.8 4.8
13000 4.8 40.6 280 14 7 8.9 4.9 | 6.2 43.2 270 10 5 9.3 5.1
12500 6.1 43.0 280 13 7 8.9 4.9 | 7.6 45.7 270 9 5 9.2 5.1
12000 7.5 45.5 280 13 7 9.2 5.0 | 8.9 48.0 270 9 5 9.2 5.0
11500 8.8 47.8 280 12 6 9.2 5.1 | 10.3 50.5 275 9 4 9.3 5.1
11000 10.1 50.2 280 12 6 8.0 4.4 | 11.6 52.9 275 8 4 8.1 4.4
10500 11.3 52.3 280 11 6 10.6 5.8 | 12.8 55.0 275 8 4 11.5 6.3
10250 12.2 54.0 280 11 6 11.3 6.2 | 13.8 56.8 275 8 4 12.3 6.8
10000 12.9 55.2 280 11 5 8.4 4.6 | 14.5 58.1 275 8 4 8.3 4.6
9750 13.6 56.5 280 10 5 9.2 5.0 | 15.2 59.4 275 8 4 9.4 5.1
9500 14.2 57.6 285 10 5 8.9 4.9 | 15.9 60.6 275 8 4 9.2 5.1
9250 14.9 58.8 285 10 5 8.5 4.7 | 17.1 62.8 275 7 4 8.6 4.7
9000 15.5 59.9 285 9 5 9.1 5.0 | 17.8 64.0 275 7 4 10.0 5.5
8750 16.2 61.2 285 9 5 9.9 5.4 | 18.6 65.5 280 7 4 9.7 5.3
8500 16.9 62.4 285 9 5 9.6 5.2 | 19.3 66.7 280 7 4 8.4 4.6
8250 18.1 64.6 290 9 5 8.8 4.8 | 19.8 67.6 275 7 3 8.6 4.7
8000 18.9 66.0 290 9 4 12.0 6.6 | 20.6 69.1 280 7 3 10.1 5.5
7750 19.7 67.5 290 9 4 10.4 5.7 | 21.3 70.3 280 7 3 9.6 5.3
7500 20.4 68.7 290 8 4 7.7 4.2 | 22.0 71.6 280 7 3 8.9 4.9
7250 21.0 69.8 290 8 4 8.1 4.4 | 22.6 72.7 280 6 3 9.0 4.9
7000 21.7 71.1 290 8 4 12.9 7.1 | 23.3 73.9 280 6 3 10.4 5.7
6750 22.8 73.0 290 8 4 12.3 6.8 | 24.1 75.4 280 6 3 10.9 6.0
6500 23.5 74.3 290 8 4 9.8 5.4 | 24.9 76.8 280 6 3 10.8 5.9
6250 24.3 75.7 295 8 4 9.5 5.2 | 25.7 78.3 280 6 3 10.8 5.9
6000 25.0 77.0 295 7 4 12.7 7.0 | 26.5 79.7 280 6 3 9.1 5.0
5750 26.4 79.5 295 7 4 26.2 14.4 | 27.2 81.0 280 6 3 12.8 7.0
5500 28.8 83.8 300 6 3 35.5 19.5 | 29.1 84.4 285 5 3 47.4 26.0
5250 M M M M M M M | M M M M M M M
5000 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) 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 at Walker Field in Grand
Junction, Colorado at
North Latitude: 39 deg 07 min 00.001 sec
West Longitude: 108 deg 31 min 59.998 sec
Elevation: 4839 feet (1475 meters)
and may not be representative of other areas along the Western Slope of
Colorado. 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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