Soaring Guidance
Issued by NWS Grand Junction, CO
Issued by NWS Grand Junction, CO
425
UXUS97 KGJT 071307
SRGGJT
Soaring Forecast
National Weather Service Grand Junction, Colorado
707 AM MDT Sunday, July 7, 2024
This forecast is for Sunday, July 7, 2024:
If the trigger temperature of 85.2 F/29.5 C is reached...then
Thermal Soaring Index....................... Excellent
Maximum rate of lift........................ 1520 ft/min (7.7 m/s)
Maximum height of thermals.................. 20499 ft MSL (15660 ft AGL)
Forecast maximum temperature................... 94.0 F/34.9 C
Time of trigger temperature.................... 1130 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................. 13126 ft MSL (8287 ft AGL)
Thermal soaring outlook for Monday 07/08....... Excellent
Wave Soaring Index............................. Not available
Remarks...
Sunrise/Sunset.................... 05:55:41 / 20:42:45 MDT
Total possible sunshine........... 14 hr 47 min 5 sec (887 min 5 sec)
Altitude of sun at 13:19:13 MDT... 72.85 degrees
Upper air data from rawinsonde observation taken on 07/07/2024 at 0600 MDT
Freezing level.................. 15409 ft MSL (10570 ft AGL)
Convective condensation level... 22522 ft MSL (17683 ft AGL)
Lifted condensation level....... 22320 ft MSL (17481 ft AGL)
Lifted index.................... +0.7
K index......................... +6.8
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 -58.8 -73.8 290 34 17 3.6 2.0 96.9 206.4 36.2 M M
45000 -52.5 -62.5 305 59 30 1.9 1.1 81.8 179.3 29.5 M M
40000 -54.0 -65.2 310 58 30 8.0 4.4 56.8 134.2 14.8 M M
38000 -49.5 -57.1 305 57 29 6.6 3.6 54.7 130.5 13.8 M M
36000 -45.5 -49.9 305 59 30 6.9 3.8 52.1 125.8 12.4 M M
34000 -42.1 -43.8 310 54 28 4.7 2.6 48.7 119.7 10.2 M M
32000 -39.3 -38.7 320 47 24 5.0 2.7 44.5 112.1 7.4 M M
30000 -34.1 -29.4 320 45 23 7.4 4.1 42.6 108.6 6.2 M M
29000 -31.9 -25.4 320 40 21 8.1 4.4 41.7 107.0 5.5 M M
28000 -29.2 -20.6 310 44 23 9.2 5.1 41.3 106.3 5.3 M M
27000 -26.7 -16.1 315 42 22 8.2 4.5 40.8 105.5 5.0 M M
26000 -24.3 -11.7 310 36 19 8.6 4.7 40.1 104.2 4.5 M M
25000 -21.7 -7.1 310 42 22 7.6 4.2 39.7 103.4 4.2 M M
24000 -20.8 -5.4 315 47 24 6.2 3.4 37.2 99.0 2.2 M M
23000 -18.8 -1.8 320 46 24 6.4 3.5 36.2 97.1 1.4 M M
22000 -16.5 2.3 315 45 23 8.7 4.8 35.4 95.7 0.7 M M
21000 -13.9 7.0 315 50 26 8.6 4.7 35.0 95.0 0.4 M M
20000 -12.1 10.2 315 57 29 4.4 2.4 33.8 92.8 -0.7 1491 7.6
19500 -11.2 11.8 310 56 29 9.2 5.0 33.3 91.9 -1.2 1448 7.4
19000 -9.8 14.4 315 56 29 9.4 5.2 33.1 91.6 -1.4 1393 7.1
18500 -8.4 16.9 315 50 26 9.4 5.2 33.1 91.6 -1.4 1336 6.8
18000 -7.0 19.4 315 51 26 9.4 5.2 33.0 91.4 -1.5 1280 6.5
17500 -5.6 21.9 310 48 25 9.0 4.9 33.0 91.3 -1.6 1223 6.2
17000 -3.7 25.3 305 44 23 8.3 4.6 32.6 90.7 -1.9 1144 5.8
16500 -2.5 27.5 305 42 22 8.3 4.6 32.4 90.3 -2.1 1092 5.5
16000 -1.2 29.8 300 40 21 8.4 4.6 32.2 89.9 -2.3 1040 5.3
15500 0.0 32.0 300 39 20 8.5 4.7 31.9 89.5 -2.6 988 5.0
15000 1.4 34.5 295 36 19 9.8 5.4 31.8 89.3 -2.7 933 4.7
14500 2.7 36.9 295 35 18 9.1 5.0 31.8 89.2 -2.8 877 4.5
14000 4.1 39.4 300 32 16 9.1 5.0 31.7 89.1 -2.8 821 4.2
13500 5.5 41.9 300 30 15 9.1 5.0 31.6 88.9 -2.9 765 3.9
13000 6.8 44.2 300 27 14 9.1 5.0 31.5 88.8 -3.0 710 3.6
12500 8.2 46.8 300 24 12 9.1 5.0 31.4 88.6 -3.1 654 3.3
12000 9.6 49.3 295 20 10 9.1 5.0 31.3 88.4 -3.3 598 3.0
11500 10.9 51.6 295 19 10 9.1 5.0 31.2 88.2 -3.4 543 2.8
11000 12.3 54.1 290 18 9 9.1 5.0 31.1 88.0 -3.5 487 2.5
10500 13.6 56.5 295 15 8 8.9 4.9 31.0 87.8 -3.6 431 2.2
10250 14.3 57.7 305 13 7 7.9 4.3 30.9 87.6 -3.8 405 2.1
10000 14.8 58.6 305 13 7 7.5 4.1 30.7 87.3 -3.9 381 1.9
9750 15.4 59.7 290 9 5 7.6 4.2 30.6 87.0 -4.1 356 1.8
9500 16.0 60.8 270 7 4 7.6 4.2 30.4 86.7 -4.3 332 1.7
9250 16.6 61.9 275 6 3 7.6 4.2 30.2 86.4 -4.4 307 1.6
9000 17.1 62.8 265 5 3 7.6 4.2 30.1 86.1 -4.6 283 1.4
8750 17.7 63.9 260 4 2 7.6 4.2 29.9 85.8 -4.8 258 1.3
8500 18.3 64.9 245 3 2 7.6 4.2 29.7 85.5 -4.9 234 1.2
8250 18.8 65.8 250 3 2 7.6 4.2 29.5 85.2 -5.1 210 1.1
8000 19.4 66.9 245 3 2 7.6 4.2 29.4 84.9 -5.3 185 0.9
7750 20.0 68.0 230 3 1 7.6 4.2 29.2 84.6 -5.5 161 0.8
7500 20.5 68.9 200 2 1 7.7 4.2 29.0 84.3 -5.6 136 0.7
7250 21.1 70.0 160 2 1 5.6 3.1 28.8 83.9 -5.9 113 0.6
7000 21.4 70.5 135 3 1 3.9 2.2 28.4 83.1 -6.3 96 0.5
6750 21.7 71.1 145 5 3 4.5 2.5 28.0 82.4 -6.7 79 0.4
6500 22.0 71.6 155 9 5 2.9 1.6 27.5 81.6 -7.1 62 0.3
6250 22.1 71.8 160 12 6 1.2 0.6 26.9 80.5 -7.8 51 0.3
6000 22.3 72.1 160 16 8 3.1 1.7 26.3 79.4 -8.4 40 0.2
5750 22.4 72.3 150 16 8 -2.8 -1.5 25.7 78.3 -9.0 29 0.1
5500 21.7 71.1 145 15 8 -10.1 -5.5 24.4 75.9 -10.4 41 0.2
5250 21.0 69.8 130 14 7 -9.0 -4.9 22.9 73.3 -12.0 57 0.3
5000 20.2 68.4 115 14 7 -10.6 -5.8 21.5 70.7 -13.5 73 0.4
* * * * * * Numerical weather prediction model forecast data valid * * * * * *
07/07/2024 at 0900 MDT | 07/07/2024 at 1200 MDT
|
CAPE... 0.0 LI... +3.9 | CAPE... 0.0 LI... +3.5
CINH... -1.1 K Index... -2.0 | CINH... 0.0 K Index... -0.7
|
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 -57.9 -72.2 315 33 17 2.2 1.2 | -57.6 -71.7 315 32 16 2.1 1.1
45000 -55.1 -67.2 315 45 23 0.9 0.5 | -55.0 -67.0 315 42 22 0.5 0.3
40000 -53.2 -63.8 310 51 26 5.8 3.2 | -53.6 -64.5 310 50 26 5.9 3.2
38000 -49.8 -57.6 310 50 26 5.6 3.1 | -50.2 -58.4 310 51 26 5.7 3.1
36000 -46.5 -51.7 315 49 25 5.6 3.1 | -46.8 -52.2 315 52 27 5.7 3.1
34000 -42.7 -44.9 315 45 23 6.4 3.5 | -42.8 -45.0 315 48 25 6.9 3.8
32000 -38.8 -37.8 320 40 21 6.5 3.6 | -38.6 -37.5 310 43 22 7.0 3.8
30000 -34.3 -29.7 320 39 20 8.0 4.4 | -34.2 -29.6 310 40 21 7.6 4.2
29000 -31.9 -25.4 320 39 20 8.0 4.4 | -31.9 -25.4 310 39 20 7.6 4.2
28000 -29.5 -21.1 320 39 20 8.0 4.4 | -29.7 -21.5 310 38 20 7.6 4.2
27000 -27.2 -17.0 320 39 20 7.7 4.2 | -27.3 -17.1 315 38 19 8.0 4.4
26000 -24.9 -12.8 315 39 20 7.7 4.2 | -24.9 -12.8 315 38 19 8.0 4.4
25000 -22.0 -7.6 315 39 20 7.7 4.2 | -21.9 -7.4 315 38 19 7.9 4.3
24000 -19.8 -3.6 315 40 20 7.4 4.1 | -19.6 -3.3 315 37 19 7.7 4.2
23000 -17.6 0.3 315 40 21 7.4 4.1 | -17.3 0.9 315 36 19 7.7 4.2
22000 -15.4 4.3 315 41 21 7.4 4.1 | -15.0 5.0 315 35 18 7.5 4.1
21000 -13.1 8.4 315 40 21 7.4 4.1 | -12.9 8.8 315 34 18 7.0 3.9
20000 -10.9 12.4 315 40 20 7.4 4.1 | -10.7 12.7 315 34 17 7.1 3.9
19500 -9.8 14.4 315 40 20 7.4 4.1 | -9.7 14.5 315 33 17 7.0 3.9
19000 -8.7 16.3 310 39 20 7.9 4.3 | -8.6 16.5 315 33 17 7.4 4.0
18500 -7.5 18.5 310 38 20 7.8 4.3 | -7.5 18.5 315 32 16 7.3 4.0
18000 -6.3 20.7 310 37 19 7.8 4.3 | -6.4 20.5 315 31 16 7.3 4.0
17500 -5.2 22.6 310 36 18 7.8 4.3 | -5.4 22.3 315 29 15 7.2 3.9
17000 -4.0 24.8 310 34 18 7.9 4.3 | -4.3 24.3 310 28 14 7.2 3.9
16500 -2.8 27.0 310 32 17 7.4 4.0 | -3.2 26.2 310 27 14 7.9 4.3
16000 -1.7 28.9 310 30 16 7.4 4.1 | -2.0 28.4 310 25 13 7.8 4.3
15500 -0.6 30.9 310 29 15 7.5 4.1 | -0.9 30.4 310 24 12 8.2 4.5
15000 0.5 32.9 305 27 14 7.6 4.1 | 0.4 32.7 305 23 12 8.3 4.5
14500 1.6 34.9 305 26 13 7.9 4.3 | 1.6 34.9 305 21 11 8.4 4.6
14000 2.8 37.0 300 25 13 8.4 4.6 | 2.9 37.2 305 20 11 8.7 4.7
13500 4.0 39.2 300 24 12 8.4 4.6 | 4.2 39.6 300 19 10 8.7 4.8
13000 5.3 41.5 295 23 12 8.7 4.8 | 5.5 41.9 300 19 10 8.8 4.8
12500 6.6 43.9 295 22 11 8.7 4.8 | 6.8 44.2 300 18 9 8.8 4.8
12000 7.9 46.2 290 21 11 8.8 4.8 | 8.1 46.6 300 18 9 9.0 5.0
11500 9.1 48.4 290 19 10 8.9 4.9 | 9.4 48.9 300 17 9 9.1 5.0
11000 10.4 50.7 285 18 9 7.7 4.2 | 10.7 51.3 300 17 9 8.0 4.4
10500 11.5 52.7 285 17 9 8.6 4.7 | 11.8 53.2 295 16 8 10.8 5.9
10250 12.2 54.0 280 16 8 9.7 5.3 | 12.8 55.0 295 16 8 11.5 6.3
10000 12.9 55.2 280 14 7 8.3 4.6 | 13.5 56.3 295 15 8 8.5 4.7
9750 13.5 56.3 275 14 7 7.6 4.2 | 14.1 57.4 295 15 7 9.3 5.1
9500 14.1 57.4 275 13 7 7.8 4.3 | 14.8 58.6 295 14 7 9.2 5.0
9250 14.6 58.3 270 12 6 7.6 4.1 | 15.5 59.9 295 14 7 7.9 4.3
9000 15.2 59.4 270 12 6 7.4 4.1 | 16.0 60.8 295 13 7 8.4 4.6
8750 16.3 61.3 265 9 5 7.4 4.1 | 16.7 62.1 295 13 6 9.9 5.4
8500 16.8 62.2 260 8 4 6.0 3.3 | 17.4 63.3 295 12 6 9.6 5.2
8250 17.2 63.0 255 8 4 5.6 3.1 | 18.5 65.3 295 11 6 8.0 4.4
8000 17.7 63.9 250 6 3 6.7 3.7 | 19.3 66.7 295 11 6 11.8 6.5
7750 18.2 64.8 240 5 3 6.0 3.3 | 20.2 68.4 290 10 5 10.4 5.7
7500 18.5 65.3 225 5 2 3.9 2.1 | 20.8 69.4 290 10 5 7.7 4.2
7250 18.8 65.8 215 4 2 3.8 2.1 | 21.4 70.5 295 10 5 7.8 4.3
7000 19.2 66.6 200 4 2 8.1 4.4 | 22.1 71.8 295 10 5 12.5 6.9
6750 19.9 67.8 185 4 2 8.1 4.4 | 23.1 73.6 290 9 5 12.3 6.8
6500 20.3 68.5 175 4 2 5.6 3.1 | 23.9 75.0 290 9 5 9.9 5.5
6250 20.7 69.3 165 4 2 5.4 3.0 | 24.7 76.5 295 9 5 9.7 5.3
6000 21.2 70.2 160 3 2 8.9 4.9 | 25.4 77.7 295 9 5 11.6 6.4
5750 22.2 72.0 160 3 2 18.6 10.2 | 26.6 79.9 290 8 4 23.2 12.7
5500 23.6 74.5 145 3 1 13.2 7.2 | 29.1 84.4 295 8 4 45.7 25.1
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
07/07/2024 at 1500 MDT | 07/07/2024 at 1800 MDT
|
CAPE... 0.0 LI... +1.4 | CAPE... 0.0 LI... +0.6
CINH... 0.0 K Index... +2.7 | CINH... -0.1 K Index... +6.9
|
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 -57.7 -71.9 315 30 15 2.0 1.1 | -56.9 -70.4 320 29 15 2.0 1.1
45000 -55.2 -67.4 320 41 21 0.4 0.2 | -54.6 -66.3 320 38 19 0.2 0.1
40000 -54.0 -65.2 315 49 25 6.0 3.3 | -53.8 -64.8 325 46 24 5.7 3.1
38000 -50.5 -58.9 315 49 25 5.8 3.2 | -50.5 -58.9 325 47 24 5.5 3.0
36000 -47.0 -52.6 315 50 26 5.8 3.2 | -47.2 -53.0 325 48 25 5.5 3.0
34000 -42.9 -45.2 315 48 25 7.1 3.9 | -43.1 -45.6 325 46 24 7.2 3.9
32000 -38.7 -37.7 315 46 24 7.2 3.9 | -38.8 -37.8 320 44 22 7.2 4.0
30000 -34.2 -29.6 315 43 22 7.6 4.2 | -34.4 -29.9 320 40 21 7.5 4.1
29000 -31.9 -25.4 315 41 21 7.6 4.2 | -32.1 -25.8 320 38 20 7.5 4.1
28000 -29.6 -21.3 315 39 20 7.7 4.2 | -29.9 -21.8 315 36 19 7.5 4.1
27000 -27.2 -17.0 315 37 19 7.9 4.3 | -27.5 -17.5 315 34 17 8.0 4.4
26000 -24.9 -12.8 315 35 18 7.9 4.3 | -25.1 -13.2 315 32 16 8.0 4.4
25000 -21.9 -7.4 315 33 17 7.8 4.3 | -22.2 -8.0 315 29 15 7.8 4.3
24000 -19.6 -3.3 315 31 16 7.6 4.1 | -20.0 -4.0 310 28 14 7.2 4.0
23000 -17.4 0.7 315 30 15 7.6 4.1 | -17.8 -0.0 305 27 14 7.2 4.0
22000 -15.1 4.8 315 28 15 7.2 4.0 | -15.7 3.7 300 26 13 7.4 4.0
21000 -13.1 8.4 310 27 14 6.7 3.7 | -13.4 7.9 295 24 12 7.6 4.1
20000 -11.1 12.0 310 26 13 6.8 3.7 | -11.2 11.8 290 23 12 7.6 4.2
19500 -10.1 13.8 310 25 13 6.7 3.7 | -10.1 13.8 290 22 12 7.6 4.1
19000 -9.1 15.6 310 25 13 7.6 4.2 | -8.9 16.0 290 22 11 9.0 5.0
18500 -8.0 17.6 305 24 12 7.6 4.2 | -7.6 18.3 290 21 11 8.9 4.9
18000 -6.9 19.6 305 23 12 8.2 4.5 | -6.2 20.8 290 21 11 9.1 5.0
17500 -5.6 21.9 305 22 11 8.7 4.8 | -4.9 23.2 290 20 10 9.2 5.1
17000 -4.2 24.4 305 21 11 8.8 4.8 | -3.5 25.7 295 19 10 9.2 5.1
16500 -2.9 26.8 305 21 11 9.4 5.1 | -2.1 28.2 295 18 9 9.5 5.2
16000 -1.5 29.3 305 20 10 9.3 5.1 | -0.7 30.7 295 17 9 9.5 5.2
15500 -0.1 31.8 305 20 10 9.1 5.0 | 0.7 33.3 300 17 9 9.4 5.2
15000 1.2 34.2 305 19 10 9.1 5.0 | 2.1 35.8 300 16 8 9.4 5.1
14500 2.6 36.7 305 18 9 9.2 5.0 | 3.5 38.3 305 15 8 9.4 5.2
14000 4.0 39.2 305 18 9 9.2 5.1 | 4.9 40.8 310 15 8 9.4 5.2
13500 5.3 41.5 305 17 9 9.3 5.1 | 6.4 43.5 310 14 7 9.4 5.2
13000 6.7 44.1 305 17 9 9.4 5.2 | 7.8 46.0 315 14 7 9.4 5.2
12500 8.1 46.6 305 17 8 9.4 5.2 | 9.2 48.6 315 13 7 9.4 5.2
12000 9.5 49.1 305 16 8 9.4 5.2 | 10.6 51.1 320 13 7 9.5 5.2
11500 10.9 51.6 305 16 8 9.6 5.3 | 12.0 53.6 320 13 7 9.7 5.3
11000 12.2 54.0 300 15 8 7.7 4.2 | 13.3 55.9 325 13 6 7.8 4.3
10500 13.3 55.9 300 15 8 12.1 6.6 | 14.5 58.1 325 12 6 10.9 6.0
10250 14.5 58.1 300 15 8 13.2 7.3 | 15.5 59.9 325 12 6 12.7 7.0
10000 15.2 59.4 300 14 7 8.4 4.6 | 16.3 61.3 325 12 6 9.4 5.1
9750 15.9 60.6 300 14 7 9.7 5.3 | 17.0 62.6 330 12 6 9.3 5.1
9500 16.6 61.9 300 14 7 9.5 5.2 | 17.7 63.9 330 12 6 9.8 5.4
9250 17.3 63.1 300 14 7 7.9 4.3 | 18.4 65.1 330 12 6 8.0 4.4
9000 17.8 64.0 300 14 7 9.0 5.0 | 18.9 66.0 330 12 6 8.5 4.7
8750 18.6 65.5 300 13 7 11.3 6.2 | 20.4 68.7 330 11 6 10.3 5.7
8500 20.2 68.4 300 13 7 8.6 4.7 | 21.2 70.2 335 11 6 8.6 4.7
8250 20.8 69.4 300 13 7 9.2 5.0 | 21.8 71.2 335 11 6 8.7 4.8
8000 21.6 70.9 300 13 7 11.8 6.5 | 22.5 72.5 335 11 5 10.6 5.8
7750 22.5 72.5 300 13 7 10.7 5.9 | 23.3 73.9 335 10 5 10.0 5.5
7500 23.2 73.8 300 12 6 8.6 4.7 | 24.0 75.2 335 10 5 8.8 4.8
7250 23.8 74.8 300 12 6 8.5 4.7 | 24.6 76.3 335 10 5 8.8 4.8
7000 24.6 76.3 300 12 6 11.7 6.4 | 25.4 77.7 335 10 5 11.0 6.0
6750 25.5 77.9 300 12 6 11.8 6.5 | 26.2 79.2 340 9 5 11.2 6.1
6500 26.3 79.3 300 12 6 10.4 5.7 | 27.0 80.6 340 9 5 10.0 5.5
6250 27.0 80.6 300 11 6 10.3 5.7 | 27.8 82.0 340 9 5 10.2 5.6
6000 27.8 82.0 300 11 6 9.8 5.4 | 28.5 83.3 340 9 5 7.8 4.3
5750 28.8 83.8 300 10 5 19.1 10.5 | 29.0 84.2 340 8 4 10.6 5.8
5500 31.7 89.1 300 10 5 70.5 38.7 | 31.2 88.2 340 8 4 61.1 33.5
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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