Soaring Guidance
Issued by NWS Grand Junction, CO
Issued by NWS Grand Junction, CO
774
UXUS97 KGJT 141307
SRGGJT
Soaring Forecast
National Weather Service Grand Junction, Colorado
707 AM MDT Sunday, July 14, 2024
This forecast is for Sunday, July 14, 2024:
If the trigger temperature of 92.2 F/33.4 C is reached...then
Thermal Soaring Index....................... Excellent
Maximum rate of lift........................ 1702 ft/min (8.6 m/s)
Maximum height of thermals.................. 22140 ft MSL (17301 ft AGL)
Forecast maximum temperature................... 102.0 F/39.3 C
Time of trigger temperature.................... 1045 MDT
Time of overdevelopment........................ 1800 MDT
Middle/high clouds during soaring window....... None
Surface winds during soaring window............ 20 mph or less
Height of the -3 thermal index................. 14971 ft MSL (10131 ft AGL)
Thermal soaring outlook for Monday 07/15....... Excellent
Wave Soaring Index............................. Not available
Remarks...
Sunrise/Sunset.................... 06:00:28 / 20:39:47 MDT
Total possible sunshine........... 14 hr 39 min 18 sec (879 min 18 sec)
Altitude of sun at 13:20:07 MDT... 71.87 degrees
Upper air data from rawinsonde observation taken on 07/14/2024 at 0600 MDT
Freezing level.................. 16811 ft MSL (11972 ft AGL)
Convective condensation level... 18480 ft MSL (13641 ft AGL)
Lifted condensation level....... 19627 ft MSL (14788 ft AGL)
Lifted index.................... -3.1
K index......................... +20.9
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 -64.1 -83.4 260 24 12 1.4 0.8 86.7 188.0 27.8 M M
45000 -58.5 -73.3 345 12 6 3.4 1.9 70.4 158.7 19.7 M M
40000 -52.1 -61.8 310 28 14 5.4 2.9 57.8 136.1 12.7 M M
38000 -48.8 -55.8 290 21 11 5.4 2.9 53.9 129.0 10.3 M M
36000 -45.0 -49.0 295 20 10 9.0 5.0 51.0 123.8 8.5 M M
34000 -39.5 -39.1 290 20 10 6.8 3.7 50.6 123.1 8.5 M M
32000 -34.0 -29.2 280 17 9 8.6 4.7 49.1 120.5 7.6 M M
30000 -28.6 -19.5 275 18 9 9.0 4.9 48.6 119.4 7.3 M M
29000 -26.2 -15.2 265 15 8 7.2 3.9 47.9 118.3 6.9 M M
28000 -24.1 -11.4 285 16 8 6.9 3.8 46.9 116.4 6.1 M M
27000 -21.9 -7.4 255 12 6 7.9 4.3 46.0 114.7 5.4 M M
26000 -20.0 -4.0 240 6 3 5.5 3.0 44.7 112.5 4.5 M M
25000 -18.5 -1.3 230 10 5 4.8 2.7 43.0 109.5 3.1 M M
24000 -16.8 1.8 220 6 3 7.4 4.1 41.5 106.7 1.9 M M
23000 -14.8 5.4 250 13 7 6.0 3.3 40.4 104.7 1.0 M M
22000 -13.0 8.6 240 13 7 6.3 3.5 39.1 102.4 -0.1 1694 8.6
21000 -11.2 11.8 225 11 6 6.5 3.6 37.9 100.2 -1.3 1611 8.2
20000 -8.9 16.0 195 9 5 8.2 4.5 37.2 99.0 -1.9 1512 7.7
19500 -7.7 18.1 205 9 5 8.9 4.9 36.9 98.5 -2.1 1461 7.4
19000 -6.3 20.7 225 10 5 9.6 5.2 36.9 98.5 -2.2 1405 7.1
18500 -4.9 23.2 230 11 6 9.5 5.2 36.9 98.4 -2.3 1348 6.8
18000 -3.6 25.5 225 10 5 9.0 5.0 36.8 98.3 -2.4 1293 6.6
17500 -2.2 28.0 225 7 4 9.0 5.0 36.8 98.2 -2.5 1238 6.3
17000 -0.2 31.6 245 4 2 9.0 5.0 36.7 98.0 -2.6 1155 5.9
16500 1.1 34.0 260 5 2 9.0 5.0 36.6 97.8 -2.7 1100 5.6
16000 2.5 36.5 280 6 3 9.0 5.0 36.5 97.7 -2.8 1045 5.3
15500 3.8 38.8 290 8 4 9.1 5.0 36.4 97.5 -2.9 990 5.0
15000 5.2 41.4 300 9 5 9.1 5.0 36.3 97.3 -3.0 935 4.7
14500 6.5 43.7 300 9 5 9.1 5.0 36.2 97.1 -3.1 880 4.5
14000 7.9 46.2 295 10 5 9.1 5.0 36.0 96.9 -3.3 825 4.2
13500 9.2 48.6 295 11 6 9.1 5.0 35.9 96.6 -3.4 769 3.9
13000 10.6 51.1 300 12 6 9.1 5.0 35.8 96.4 -3.6 714 3.6
12500 11.9 53.4 295 8 4 9.1 5.0 35.6 96.1 -3.7 659 3.3
12000 13.2 55.8 280 5 3 9.1 5.0 35.5 95.9 -3.9 604 3.1
11500 14.6 58.3 240 4 2 9.1 5.0 35.3 95.6 -4.1 549 2.8
11000 15.9 60.6 205 5 3 9.1 5.0 35.2 95.3 -4.3 494 2.5
10500 17.3 63.1 185 7 4 8.6 4.7 35.0 95.0 -4.5 440 2.2
10250 17.9 64.2 175 8 4 8.4 4.6 34.9 94.8 -4.6 414 2.1
10000 18.5 65.3 170 9 5 8.5 4.7 34.8 94.6 -4.7 388 2.0
9750 19.1 66.4 160 10 5 8.5 4.6 34.7 94.4 -4.8 362 1.8
9500 19.7 67.5 155 11 6 8.5 4.7 34.6 94.3 -4.9 336 1.7
9250 20.3 68.5 155 13 6 8.5 4.6 34.5 94.1 -5.1 310 1.6
9000 21.0 69.8 150 14 7 8.6 4.7 34.4 94.0 -5.2 284 1.4
8750 21.6 70.9 145 14 7 8.0 4.4 34.3 93.8 -5.3 258 1.3
8500 22.1 71.8 145 14 7 6.7 3.7 34.1 93.4 -5.5 235 1.2
8250 22.6 72.7 140 14 7 6.5 3.6 33.9 93.0 -5.8 213 1.1
8000 23.1 73.6 145 15 8 6.6 3.6 33.6 92.6 -6.0 191 1.0
7750 23.6 74.5 145 15 8 6.6 3.6 33.4 92.1 -6.3 169 0.9
7500 24.0 75.2 140 16 8 6.6 3.6 33.2 91.7 -6.5 148 0.7
7250 24.5 76.1 140 16 8 6.6 3.6 32.9 91.2 -6.8 126 0.6
7000 25.0 77.0 145 17 9 6.6 3.6 32.7 90.8 -7.1 104 0.5
6750 25.5 77.9 145 17 9 6.7 3.7 32.4 90.4 -7.3 82 0.4
6500 26.0 78.8 145 17 9 6.2 3.4 32.2 89.9 -7.6 60 0.3
6250 26.4 79.5 140 18 9 7.6 4.2 31.9 89.5 -7.9 39 0.2
6000 26.7 80.1 135 19 10 -4.4 -2.4 31.5 88.7 -8.3 22 0.1
5750 26.0 78.8 135 19 10 -5.2 -2.9 30.1 86.1 -9.8 36 0.2
5500 26.3 79.3 130 20 10 8.9 4.9 29.6 85.3 -10.3 22 0.1
5250 26.5 79.7 125 20 10 -4.8 -2.6 29.3 84.7 -10.8 7 0.0
5000 25.1 77.2 120 19 10 -34.7 -19.0 27.0 80.7 -13.0 42 0.2
* * * * * * Numerical weather prediction model forecast data valid * * * * * *
07/14/2024 at 0900 MDT | 07/14/2024 at 1200 MDT
|
CAPE... +10.5 LI... -0.0 | CAPE... +144.2 LI... -0.7
CINH... -62.1 K Index... +22.6 | CINH... -24.2 K Index... +22.9
|
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 -62.1 -79.8 285 12 6 0.4 0.2 | -61.8 -79.2 290 12 6 1.1 0.6
45000 -59.1 -74.4 285 16 8 4.4 2.4 | -59.0 -74.2 300 15 8 3.3 1.8
40000 -52.1 -61.8 300 10 5 6.5 3.6 | -53.1 -63.6 280 12 6 7.4 4.1
38000 -48.2 -54.8 285 14 7 6.5 3.5 | -48.6 -55.5 270 15 8 7.4 4.0
36000 -44.3 -47.7 275 18 9 7.0 3.9 | -43.6 -46.5 265 19 10 7.9 4.4
34000 -39.0 -38.2 265 15 7 7.9 4.3 | -38.9 -38.0 260 17 9 7.9 4.3
32000 -34.3 -29.7 260 12 6 8.5 4.7 | -34.2 -29.6 260 15 8 8.5 4.7
30000 -29.5 -21.1 255 10 5 8.0 4.4 | -29.4 -20.9 240 12 6 8.0 4.4
29000 -27.1 -16.8 250 8 4 8.0 4.4 | -27.0 -16.6 230 11 6 8.0 4.4
28000 -24.9 -12.8 250 8 4 7.1 3.9 | -24.7 -12.5 220 11 6 7.2 3.9
27000 -22.7 -8.9 245 7 4 7.1 3.9 | -22.6 -8.7 215 11 5 7.2 4.0
26000 -20.6 -5.1 245 7 4 7.1 3.9 | -20.4 -4.7 210 10 5 7.3 4.0
25000 -18.5 -1.3 240 7 4 6.9 3.8 | -18.3 -0.9 205 10 5 6.8 3.7
24000 -16.5 2.3 235 8 4 6.9 3.8 | -16.4 2.5 210 11 6 6.7 3.7
23000 -14.5 5.9 230 10 5 7.0 3.8 | -14.4 6.1 210 11 6 6.7 3.7
22000 -12.5 9.5 225 11 5 6.8 3.7 | -12.0 10.4 220 11 6 6.9 3.8
21000 -10.0 14.0 235 11 5 6.9 3.8 | -10.0 14.0 225 11 5 7.0 3.8
20000 -8.0 17.6 240 11 5 6.8 3.7 | -7.9 17.8 235 10 5 6.9 3.8
19500 -7.0 19.4 240 10 5 8.0 4.4 | -6.9 19.6 240 10 5 8.2 4.5
19000 -5.8 21.6 245 10 5 8.1 4.4 | -5.7 21.7 245 10 5 8.3 4.6
18500 -4.6 23.7 250 9 5 8.4 4.6 | -4.4 24.1 250 9 5 8.4 4.6
18000 -3.3 26.1 255 9 5 9.2 5.0 | -3.2 26.2 255 9 5 8.9 4.9
17500 -1.9 28.6 260 9 4 9.2 5.0 | -1.9 28.6 255 9 4 8.8 4.8
17000 -0.6 30.9 260 8 4 9.3 5.1 | -0.5 31.1 260 8 4 9.4 5.2
16500 0.8 33.4 265 8 4 9.3 5.1 | 0.9 33.6 260 8 4 9.5 5.2
16000 2.2 36.0 265 8 4 9.3 5.1 | 2.3 36.1 265 8 4 9.4 5.2
15500 3.5 38.3 265 8 4 9.2 5.1 | 3.7 38.7 265 8 4 9.3 5.1
15000 4.9 40.8 265 8 4 9.2 5.1 | 5.1 41.2 265 8 4 9.3 5.1
14500 6.2 43.2 265 8 4 9.0 4.9 | 6.5 43.7 265 8 4 9.4 5.2
14000 7.6 45.7 265 8 4 9.1 5.0 | 7.8 46.0 260 8 4 9.4 5.2
13500 8.9 48.0 260 8 4 8.8 4.8 | 9.2 48.6 260 7 4 9.1 5.0
13000 10.2 50.4 260 7 4 8.8 4.8 | 10.6 51.1 255 7 4 9.1 5.0
12500 11.5 52.7 260 6 3 8.7 4.8 | 11.9 53.4 255 7 4 9.1 5.0
12000 12.8 55.0 255 6 3 8.7 4.8 | 13.3 55.9 250 6 3 9.1 5.0
11500 14.1 57.4 250 5 3 8.5 4.7 | 14.6 58.3 250 6 3 9.0 5.0
11000 15.3 59.5 240 5 3 8.3 4.6 | 15.9 60.6 250 6 3 9.0 4.9
10500 16.6 61.9 235 5 3 8.2 4.5 | 17.3 63.1 250 5 3 7.5 4.1
10250 17.2 63.0 240 6 3 8.1 4.5 | 17.8 64.0 255 5 3 8.0 4.4
10000 17.8 64.0 235 6 3 8.3 4.6 | 18.5 65.3 255 5 3 9.8 5.4
9750 18.4 65.1 225 5 3 8.2 4.5 | 19.2 66.6 255 5 2 9.4 5.2
9500 19.0 66.2 220 5 3 8.6 4.7 | 19.9 67.8 255 5 2 9.1 5.0
9250 19.7 67.5 225 5 3 8.3 4.6 | 20.5 68.9 260 4 2 8.6 4.7
9000 20.2 68.4 220 5 2 7.0 3.8 | 21.2 70.2 260 4 2 8.8 4.8
8750 20.7 69.3 215 5 2 6.5 3.6 | 21.8 71.2 260 4 2 8.8 4.8
8500 21.2 70.2 205 5 2 6.0 3.3 | 22.4 72.3 260 3 2 7.9 4.3
8250 21.6 70.9 205 4 2 5.0 2.8 | 23.5 74.3 260 3 2 9.9 5.4
8000 22.6 72.7 190 4 2 7.6 4.2 | 24.4 75.9 260 3 2 12.3 6.8
7750 23.0 73.4 180 4 2 4.4 2.4 | 25.2 77.4 260 3 1 9.2 5.1
7500 23.2 73.8 170 4 2 2.3 1.3 | 25.8 78.4 260 3 1 7.3 4.0
7250 23.5 74.3 165 4 2 4.7 2.6 | 26.4 79.5 260 3 1 9.9 5.5
7000 23.9 75.0 155 4 2 7.5 4.1 | 27.3 81.1 260 3 1 12.8 7.0
6750 24.4 75.9 150 4 2 6.6 3.6 | 28.2 82.8 260 2 1 10.9 6.0
6500 24.8 76.6 140 4 2 5.7 3.1 | 28.9 84.0 260 2 1 10.2 5.6
6250 25.3 77.5 135 5 2 5.9 3.2 | 29.7 85.5 260 2 1 8.7 4.8
6000 25.8 78.4 125 3 2 11.3 6.2 | 30.4 86.7 260 2 1 15.1 8.3
5750 27.0 80.6 125 4 2 20.6 11.3 | 32.1 89.8 265 2 1 31.5 17.3
5500 28.2 82.8 125 4 2 4.1 2.3 | 33.9 93.0 265 2 1 2.9 1.6
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
07/14/2024 at 1500 MDT | 07/14/2024 at 1800 MDT
|
CAPE... +114.2 LI... -0.2 | CAPE... +75.1 LI... -0.3
CINH... -21.1 K Index... +22.3 | CINH... -17.4 K Index... +21.6
|
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 -61.4 -78.5 280 11 6 1.8 1.0 | -61.5 -78.7 295 15 8 1.4 0.8
45000 -58.3 -72.9 290 11 6 2.5 1.4 | -58.6 -73.5 280 11 6 2.7 1.5
40000 -53.3 -63.9 260 9 5 7.5 4.1 | -53.2 -63.8 215 11 6 7.7 4.2
38000 -48.8 -55.8 265 13 7 7.5 4.1 | -48.6 -55.5 235 12 6 7.7 4.2
36000 -43.7 -46.7 265 17 9 8.1 4.4 | -44.0 -47.2 245 14 7 7.9 4.3
34000 -38.8 -37.8 260 16 8 8.0 4.4 | -38.5 -37.3 245 13 7 8.2 4.5
32000 -34.0 -29.2 255 15 8 8.5 4.6 | -33.6 -28.5 240 13 7 8.3 4.6
30000 -29.3 -20.7 240 14 7 8.0 4.4 | -28.9 -20.0 240 14 7 7.8 4.3
29000 -26.9 -16.4 230 14 7 8.0 4.4 | -26.6 -15.9 235 15 8 7.8 4.3
28000 -24.6 -12.3 225 14 7 7.5 4.1 | -24.4 -11.9 235 15 8 7.2 4.0
27000 -22.3 -8.1 220 14 7 7.5 4.1 | -22.2 -8.0 235 16 8 7.3 4.0
26000 -20.1 -4.2 220 14 7 7.6 4.1 | -20.1 -4.2 235 16 8 7.3 4.0
25000 -17.9 -0.2 215 14 7 7.1 3.9 | -17.9 -0.2 240 16 8 6.9 3.8
24000 -15.9 3.4 215 14 7 7.0 3.8 | -16.0 3.2 240 14 7 6.8 3.7
23000 -13.8 7.2 215 13 7 7.1 3.9 | -14.0 6.8 250 12 6 6.8 3.7
22000 -11.3 11.7 215 12 6 7.2 4.0 | -12.0 10.4 255 10 5 7.5 4.1
21000 -9.2 15.4 225 10 5 7.3 4.0 | -9.2 15.4 265 9 5 7.7 4.2
20000 -7.0 19.4 230 9 5 7.2 4.0 | -7.0 19.4 270 9 5 7.6 4.2
19500 -6.0 21.2 235 9 4 7.9 4.4 | -5.8 21.6 275 9 5 8.4 4.6
19000 -4.8 23.4 240 8 4 8.0 4.4 | -4.6 23.7 275 9 5 8.5 4.6
18500 -3.6 25.5 250 8 4 8.2 4.5 | -3.3 26.1 275 9 5 8.5 4.7
18000 -2.3 27.9 255 8 4 8.9 4.9 | -2.1 28.2 275 9 5 8.9 4.9
17500 -1.0 30.2 260 8 4 8.8 4.8 | -0.7 30.7 275 9 5 8.8 4.8
17000 0.3 32.5 265 8 4 9.2 5.1 | 0.6 33.1 275 9 5 9.3 5.1
16500 1.7 35.1 265 8 4 9.3 5.1 | 2.0 35.6 275 9 5 9.4 5.2
16000 3.1 37.6 270 8 4 9.3 5.1 | 3.4 38.1 270 9 5 9.5 5.2
15500 4.4 39.9 270 8 4 9.3 5.1 | 4.8 40.6 270 9 5 9.5 5.2
15000 5.8 42.4 270 8 4 9.3 5.1 | 6.2 43.2 270 9 5 9.4 5.2
14500 7.2 45.0 270 8 4 9.4 5.2 | 7.6 45.7 265 9 5 9.7 5.3
14000 8.6 47.5 270 8 4 9.4 5.2 | 9.1 48.4 265 9 5 9.7 5.3
13500 10.1 50.2 270 8 4 9.6 5.3 | 10.5 50.9 265 9 5 9.5 5.2
13000 11.5 52.7 270 8 4 9.6 5.3 | 11.9 53.4 265 9 5 9.5 5.2
12500 12.9 55.2 270 8 4 9.5 5.2 | 13.3 55.9 260 10 5 9.5 5.2
12000 14.3 57.7 270 8 4 9.5 5.2 | 14.7 58.5 260 10 5 9.5 5.2
11500 15.7 60.3 270 8 4 9.5 5.2 | 16.2 61.2 260 10 5 9.5 5.2
11000 17.1 62.8 270 8 4 9.3 5.1 | 17.6 63.7 255 10 5 9.4 5.2
10500 18.6 65.5 270 8 4 7.2 4.0 | 19.0 66.2 255 10 5 8.1 4.5
10250 19.0 66.2 270 8 4 7.9 4.4 | 19.5 67.1 255 10 5 8.5 4.6
10000 19.8 67.6 270 8 4 11.2 6.2 | 20.3 68.5 255 10 5 10.6 5.8
9750 20.6 69.1 270 8 4 10.7 5.9 | 21.0 69.8 255 10 5 9.9 5.5
9500 21.4 70.5 270 8 4 9.5 5.2 | 21.8 71.2 255 10 5 10.3 5.7
9250 22.0 71.6 275 8 4 8.8 4.8 | 22.5 72.5 250 10 5 10.0 5.5
9000 22.7 72.9 270 8 4 9.9 5.4 | 23.2 73.8 250 10 5 9.4 5.2
8750 23.5 74.3 270 8 4 10.1 5.5 | 24.0 75.2 250 10 5 9.5 5.2
8500 24.2 75.6 270 8 4 9.1 5.0 | 24.7 76.5 250 10 5 9.4 5.2
8250 24.8 76.6 270 8 4 7.9 4.3 | 26.1 79.0 250 11 6 9.9 5.5
8000 26.3 79.3 270 8 4 12.0 6.6 | 26.8 80.2 250 10 5 10.7 5.9
7750 27.1 80.8 270 8 4 9.8 5.4 | 27.6 81.7 250 10 5 9.7 5.3
7500 27.8 82.0 270 7 4 8.0 4.4 | 28.3 82.9 250 10 5 8.4 4.6
7250 28.4 83.1 275 7 4 9.8 5.4 | 28.9 84.0 250 11 6 9.4 5.1
7000 29.2 84.6 270 7 4 12.0 6.6 | 29.7 85.5 250 11 5 11.1 6.1
6750 30.1 86.2 270 7 4 11.2 6.1 | 30.5 86.9 250 10 5 10.8 5.9
6500 30.9 87.6 270 7 4 10.8 5.9 | 31.3 88.3 250 10 5 10.5 5.7
6250 31.7 89.1 275 7 4 9.1 5.0 | 32.1 89.8 250 10 5 9.8 5.4
6000 32.4 90.3 270 7 3 14.2 7.8 | 32.8 91.0 250 10 5 10.8 5.9
5750 34.1 93.4 270 6 3 30.6 16.8 | 33.8 92.8 250 9 5 18.1 10.0
5500 36.2 97.2 275 6 3 15.6 8.6 | 35.5 95.9 250 9 5 26.0 14.3
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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