Soaring Guidance
Issued by NWS Grand Junction, CO
Issued by NWS Grand Junction, CO
195
UXUS97 KGJT 141307
SRGGJT
Soaring Forecast
National Weather Service Grand Junction, Colorado
707 AM MDT Friday, June 14, 2024
This forecast is for Friday, June 14, 2024:
If the trigger temperature of 74.1 F/23.4 C is reached...then
Thermal Soaring Index....................... Excellent
Maximum rate of lift........................ 1187 ft/min (6.0 m/s)
Maximum height of thermals.................. 16704 ft MSL (11865 ft AGL)
Forecast maximum temperature................... 88.0 F/31.6 C
Time of trigger temperature.................... 0845 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................. 13491 ft MSL (8651 ft AGL)
Thermal soaring outlook for Saturday 06/15..... Excellent
Wave Soaring Index............................. Not available
Remarks...
Sunrise/Sunset.................... 05:47:33 / 20:41:40 MDT
Total possible sunshine........... 14 hr 54 min 7 sec (894 min 7 sec)
Altitude of sun at 13:14:36 MDT... 73.89 degrees
Upper air data from rawinsonde observation taken on 06/14/2024 at 0600 MDT
Freezing level.................. 14437 ft MSL (9598 ft AGL)
Convective condensation level... 11721 ft MSL (6882 ft AGL)
Lifted condensation level....... 13938 ft MSL (9098 ft AGL)
Lifted index.................... -3.8
K index......................... +28.0
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 -60.4 -76.7 215 32 16 3.7 2.0 94.5 202.1 36.7 M M
45000 -52.7 -62.9 245 31 16 3.1 1.7 81.8 179.3 31.5 M M
40000 -53.5 -64.3 220 52 27 2.5 1.4 57.5 135.6 17.6 M M
38000 -51.4 -60.5 215 40 21 3.5 1.9 52.0 125.6 14.2 M M
36000 -48.7 -55.7 200 27 14 9.4 5.2 47.6 117.6 11.5 M M
34000 -43.2 -45.8 200 35 18 9.4 5.1 47.0 116.5 11.4 M M
32000 -37.2 -35.0 210 35 18 8.5 4.7 46.2 115.2 11.1 M M
30000 -31.9 -25.4 210 37 19 9.0 4.9 45.6 114.0 10.9 M M
29000 -29.2 -20.6 210 43 22 9.0 4.9 45.3 113.5 10.8 M M
28000 -26.5 -15.7 210 39 20 9.0 5.0 45.0 113.0 10.7 M M
27000 -24.1 -11.4 215 45 23 7.1 3.9 44.4 112.0 10.3 M M
26000 -22.0 -7.6 200 49 25 7.1 3.9 43.4 110.2 9.6 M M
25000 -19.9 -3.8 205 47 24 7.2 3.9 42.5 108.4 8.9 M M
24000 -17.7 0.1 205 48 25 8.3 4.6 41.6 106.9 8.3 M M
23000 -15.7 3.7 215 42 22 5.7 3.1 40.5 105.0 7.4 M M
22000 -13.5 7.7 215 41 21 7.9 4.3 39.6 103.3 6.7 M M
21000 -11.2 11.8 235 32 17 7.9 4.3 39.0 102.1 6.2 M M
20000 -8.9 16.0 235 24 12 6.0 3.3 38.3 100.9 5.7 M M
19500 -8.3 17.1 230 23 12 4.3 2.4 37.3 99.1 4.8 M M
19000 -7.6 18.3 225 26 14 5.6 3.0 36.4 97.6 4.1 M M
18500 -6.8 19.8 225 28 15 6.1 3.3 35.7 96.3 3.5 M M
18000 -5.9 21.4 220 31 16 6.3 3.5 35.1 95.2 2.9 M M
17500 -5.3 22.5 195 33 17 1.3 0.7 33.4 92.1 1.3 M M
17000 -4.9 23.2 185 37 19 3.6 2.0 32.2 90.0 0.3 M M
16500 -4.1 24.6 190 38 20 6.9 3.8 31.5 88.7 -0.4 961 4.9
16000 -3.1 26.4 180 35 18 7.4 4.1 31.0 87.8 -0.9 918 4.7
15500 -2.0 28.4 180 34 18 7.4 4.0 30.7 87.3 -1.2 868 4.4
15000 -1.0 30.2 175 30 15 6.9 3.8 30.2 86.4 -1.6 824 4.2
14500 0.0 32.0 175 29 15 6.8 3.7 29.8 85.6 -2.1 779 4.0
14000 1.0 33.8 165 29 15 6.8 3.7 29.3 84.7 -2.6 735 3.7
13500 2.0 35.6 155 18 9 6.8 3.7 28.8 83.8 -3.0 690 3.5
13000 3.0 37.4 160 12 6 6.4 3.5 28.3 83.0 -3.5 645 3.3
12500 4.0 39.2 125 5 3 1.3 0.7 27.8 82.1 -4.0 601 3.1
12000 4.5 40.1 105 8 4 10.4 5.7 26.8 80.3 -5.0 570 2.9
11500 5.8 42.4 140 7 4 8.5 4.7 26.7 80.0 -5.2 517 2.6
11000 6.7 44.1 155 9 5 5.4 3.0 26.2 79.1 -5.7 474 2.4
10500 7.7 45.9 145 9 5 8.3 4.5 25.6 78.1 -6.3 432 2.2
10250 8.3 46.9 145 9 4 9.8 5.4 25.6 78.1 -6.4 405 2.1
10000 9.0 48.2 150 8 4 8.4 4.6 25.6 78.0 -6.5 378 1.9
9750 9.5 49.1 160 10 5 7.3 4.0 25.4 77.7 -6.7 354 1.8
9500 10.1 50.2 160 9 5 7.6 4.2 25.2 77.4 -6.9 330 1.7
9250 10.6 51.1 155 8 4 7.5 4.1 25.1 77.1 -7.0 306 1.6
9000 11.2 52.2 160 6 3 7.6 4.2 24.9 76.8 -7.2 283 1.4
8750 11.7 53.1 170 6 3 7.5 4.1 24.7 76.5 -7.4 259 1.3
8500 12.3 54.1 175 6 3 7.6 4.2 24.6 76.2 -7.6 235 1.2
8250 12.8 55.0 160 5 3 7.3 4.0 24.4 75.9 -7.8 211 1.1
8000 13.3 55.9 175 5 3 8.6 4.7 24.2 75.6 -8.1 187 1.0
7750 14.1 57.4 165 5 3 11.7 6.4 24.3 75.7 -8.1 158 0.8
7500 15.0 59.0 155 6 3 12.7 7.0 24.5 76.0 -7.9 124 0.6
7250 15.9 60.6 145 6 3 12.4 6.8 24.7 76.4 -7.8 89 0.5
7000 16.8 62.2 135 7 4 12.5 6.9 24.9 76.8 -7.6 55 0.3
6750 17.7 63.9 145 7 4 12.4 6.8 25.1 77.2 -7.4 21 0.1
6500 18.6 65.5 155 7 3 12.9 7.1 25.3 77.6 -7.3 M M
6250 19.5 67.1 175 4 2 11.3 6.2 25.5 78.0 -7.1 M M
6000 20.1 68.2 230 3 2 8.6 4.7 25.5 77.9 -7.2 M M
5750 20.7 69.3 245 5 3 7.3 4.0 25.4 77.7 -7.4 M M
5500 21.0 69.8 250 8 4 5.0 2.7 25.1 77.2 -7.8 M M
5250 21.0 69.8 265 7 4 -4.6 -2.5 24.5 76.1 -8.6 M M
5000 20.6 69.1 260 10 5 -4.6 -2.5 23.2 73.8 -9.7 M M
* * * * * * Numerical weather prediction model forecast data valid * * * * * *
06/14/2024 at 0900 MDT | 06/14/2024 at 1200 MDT
|
CAPE... +115.6 LI... -0.1 | CAPE... +486.3 LI... -2.6
CINH... -145.3 K Index... +26.5 | CINH... -18.6 K Index... +30.7
|
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 -58.1 -72.6 245 26 14 4.1 2.3 | -58.2 -72.8 255 25 13 3.8 2.1
45000 -53.0 -63.4 235 31 16 1.0 0.6 | -53.0 -63.4 250 27 14 2.1 1.1
40000 -51.3 -60.3 220 34 18 2.1 1.2 | -49.9 -57.8 225 25 13 1.9 1.0
38000 -50.1 -58.2 200 36 19 2.0 1.1 | -48.7 -55.7 195 32 16 1.9 1.1
36000 -48.9 -56.0 185 42 22 2.1 1.2 | -47.5 -53.5 180 44 23 2.1 1.2
34000 -44.3 -47.7 175 41 21 9.3 5.1 | -43.5 -46.3 175 47 24 8.4 4.6
32000 -38.7 -37.7 170 39 20 9.3 5.1 | -38.5 -37.3 170 48 24 8.4 4.6
30000 -33.5 -28.3 175 38 20 8.6 4.7 | -33.5 -28.3 175 47 24 8.2 4.5
29000 -30.9 -23.6 180 39 20 8.6 4.7 | -31.1 -24.0 175 47 24 8.2 4.5
28000 -28.3 -18.9 180 39 20 8.4 4.6 | -28.0 -18.4 180 46 24 6.9 3.8
27000 -25.7 -14.3 190 38 20 6.9 3.8 | -26.2 -15.2 190 40 20 6.0 3.3
26000 -23.6 -10.5 195 38 20 6.9 3.8 | -24.4 -11.9 200 34 18 6.0 3.3
25000 -21.6 -6.9 205 39 20 6.9 3.8 | -22.6 -8.7 210 30 15 6.0 3.3
24000 -19.6 -3.3 210 35 18 6.7 3.7 | -20.6 -5.1 220 24 13 7.1 3.9
23000 -17.6 0.3 220 31 16 6.7 3.7 | -18.4 -1.1 235 20 10 7.1 3.9
22000 -15.5 4.1 230 28 14 7.1 3.9 | -16.3 2.7 255 16 8 7.0 3.9
21000 -13.2 8.2 235 25 13 8.0 4.4 | -14.3 6.3 255 14 7 7.0 3.8
20000 -10.8 12.6 240 22 11 8.0 4.4 | -12.3 9.9 245 12 6 7.1 3.9
19500 -9.6 14.7 240 20 10 8.1 4.5 | -11.3 11.7 245 10 5 7.2 3.9
19000 -8.5 16.7 245 19 10 7.0 3.8 | -10.3 13.5 240 10 5 7.0 3.8
18500 -7.5 18.5 240 18 9 7.1 3.9 | -9.2 15.4 240 9 5 7.0 3.8
18000 -6.4 20.5 240 16 8 6.5 3.6 | -8.2 17.2 240 9 5 7.2 3.9
17500 -5.6 21.9 240 16 8 5.9 3.3 | -7.2 19.0 245 9 5 7.3 4.0
17000 -4.8 23.4 235 15 8 5.9 3.2 | -6.1 21.0 245 10 5 7.3 4.0
16500 -3.9 25.0 235 15 7 6.3 3.4 | -5.0 23.0 245 10 5 8.2 4.5
16000 -3.0 26.6 235 14 7 6.2 3.4 | -3.8 25.2 245 10 5 8.1 4.5
15500 -2.1 28.2 235 14 7 7.4 4.1 | -2.6 27.3 245 10 5 8.4 4.6
15000 -1.0 30.2 235 14 7 7.7 4.2 | -1.4 29.5 240 10 5 8.5 4.7
14500 0.2 32.4 240 14 7 7.8 4.3 | -0.1 31.8 240 10 5 8.5 4.7
14000 1.3 34.3 240 14 7 7.8 4.3 | 1.1 34.0 235 11 5 8.6 4.7
13500 2.4 36.3 240 15 8 7.9 4.3 | 2.4 36.3 235 11 6 8.6 4.7
13000 3.6 38.5 240 15 8 8.3 4.5 | 3.7 38.7 230 11 6 8.7 4.8
12500 4.8 40.6 240 14 7 8.3 4.5 | 4.9 40.8 230 12 6 8.7 4.8
12000 6.1 43.0 235 14 7 8.7 4.8 | 6.2 43.2 225 12 6 8.8 4.9
11500 7.3 45.1 235 14 7 8.7 4.7 | 7.5 45.5 225 12 6 8.8 4.9
11000 8.5 47.3 230 13 7 8.0 4.4 | 8.8 47.8 220 11 6 8.6 4.7
10500 9.7 49.5 225 13 7 7.6 4.2 | 10.0 50.0 215 10 5 7.7 4.2
10250 10.2 50.4 225 12 6 6.4 3.5 | 10.6 51.1 215 9 5 7.9 4.3
10000 10.7 51.3 225 12 6 7.2 3.9 | 11.2 52.2 215 9 5 9.5 5.2
9750 11.3 52.3 220 12 6 8.1 4.4 | 11.9 53.4 210 9 5 9.2 5.1
9500 11.8 53.2 210 12 6 7.8 4.3 | 12.6 54.7 210 9 5 9.4 5.2
9250 13.0 55.4 205 12 6 6.5 3.5 | 14.1 57.4 205 8 4 9.3 5.1
9000 13.4 56.1 195 12 6 5.1 2.8 | 14.7 58.5 205 9 5 8.1 4.4
8750 13.7 56.7 190 13 7 5.3 2.9 | 15.3 59.5 200 9 5 8.4 4.6
8500 14.1 57.4 185 13 7 4.9 2.7 | 16.0 60.8 200 10 5 8.2 4.5
8250 14.4 57.9 180 13 7 4.5 2.5 | 16.6 61.9 190 9 5 8.3 4.6
8000 14.7 58.5 175 13 7 4.1 2.3 | 17.2 63.0 185 9 5 8.8 4.8
7750 15.0 59.0 170 13 7 4.1 2.3 | 17.8 64.0 185 10 5 8.1 4.4
7500 15.3 59.5 165 12 6 4.2 2.3 | 18.4 65.1 180 10 5 6.8 3.7
7250 15.5 59.9 160 11 6 4.5 2.5 | 18.9 66.0 175 10 5 7.4 4.1
7000 15.9 60.6 160 10 5 7.7 4.2 | 19.5 67.1 170 10 5 10.8 5.9
6750 16.6 61.9 160 10 5 10.0 5.5 | 20.4 68.7 170 10 5 11.7 6.4
6500 17.3 63.1 155 9 5 10.0 5.5 | 21.2 70.2 170 10 5 11.0 6.0
6250 18.1 64.6 155 9 4 9.2 5.0 | 22.0 71.6 170 9 5 10.0 5.5
6000 18.8 65.8 150 8 4 11.7 6.4 | 22.8 73.0 165 9 5 12.9 7.1
5750 19.9 67.8 155 7 4 20.1 11.0 | 24.1 75.4 170 9 4 25.5 14.0
5500 21.4 70.5 145 6 3 14.6 8.0 | 26.3 79.3 165 7 4 27.5 15.1
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
06/14/2024 at 1500 MDT | 06/14/2024 at 1800 MDT
|
CAPE... +419.5 LI... -2.3 | CAPE... +289.2 LI... -1.8
CINH... -21.9 K Index... +29.8 | CINH... -59.9 K Index... +26.7
|
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 -59.0 -74.2 260 24 12 2.9 1.6 | -58.9 -74.0 260 23 12 2.9 1.6
45000 -53.9 -65.0 265 29 15 4.2 2.3 | -54.2 -65.6 265 28 14 3.7 2.1
40000 -47.8 -54.0 280 26 13 2.0 1.1 | -48.5 -55.3 280 28 15 4.2 2.3
38000 -46.5 -51.7 245 19 10 2.2 1.2 | -46.0 -50.8 285 26 13 4.2 2.3
36000 -45.2 -49.4 200 22 11 2.3 1.2 | -43.1 -45.6 285 23 12 4.2 2.3
34000 -41.6 -42.9 180 32 16 6.4 3.5 | -40.2 -40.4 280 20 11 5.0 2.7
32000 -37.8 -36.0 170 42 22 6.5 3.5 | -37.2 -35.0 270 18 9 5.1 2.8
30000 -33.6 -28.5 175 38 20 7.2 3.9 | -33.3 -27.9 270 15 8 7.1 3.9
29000 -31.5 -24.7 180 34 17 7.2 3.9 | -31.2 -24.2 270 14 7 7.1 3.9
28000 -29.4 -20.9 185 30 15 7.1 3.9 | -29.1 -20.4 270 12 6 7.1 3.9
27000 -27.3 -17.1 190 24 12 6.8 3.8 | -27.0 -16.6 275 11 5 7.3 4.0
26000 -25.3 -13.5 200 17 9 6.9 3.8 | -24.8 -12.6 285 9 5 7.3 4.0
25000 -23.3 -9.9 220 11 6 6.9 3.8 | -22.6 -8.7 295 8 4 7.4 4.0
24000 -21.2 -6.2 235 9 5 7.1 3.9 | -20.5 -4.9 300 8 4 6.9 3.8
23000 -19.1 -2.4 240 8 4 7.1 3.9 | -18.4 -1.1 295 7 4 6.9 3.8
22000 -17.0 1.4 250 8 4 7.0 3.9 | -15.9 3.4 295 7 4 7.1 3.9
21000 -14.2 6.4 255 8 4 7.7 4.2 | -13.7 7.3 290 8 4 7.6 4.2
20000 -12.0 10.4 260 9 5 7.8 4.3 | -11.4 11.5 290 9 5 7.6 4.2
19500 -10.9 12.4 260 10 5 7.8 4.3 | -10.3 13.5 290 10 5 7.6 4.2
19000 -9.8 14.4 260 10 5 7.4 4.1 | -9.2 15.4 290 10 5 7.9 4.3
18500 -8.7 16.3 265 10 5 7.5 4.1 | -8.0 17.6 290 11 6 7.9 4.3
18000 -7.6 18.3 265 10 5 7.6 4.2 | -6.9 19.6 290 12 6 7.7 4.2
17500 -6.4 20.5 265 11 5 7.7 4.2 | -5.8 21.6 290 12 6 7.6 4.2
17000 -5.3 22.5 265 11 5 7.8 4.3 | -4.7 23.5 290 13 6 7.6 4.2
16500 -4.2 24.4 265 11 5 8.0 4.4 | -3.6 25.5 290 12 6 8.1 4.4
16000 -3.0 26.6 265 11 5 7.9 4.4 | -2.4 27.7 290 12 6 8.1 4.4
15500 -1.8 28.8 265 11 5 8.3 4.5 | -1.2 29.8 290 12 6 8.4 4.6
15000 -0.6 30.9 265 10 5 8.3 4.6 | 0.0 32.0 285 11 6 8.5 4.7
14500 0.6 33.1 265 10 5 8.4 4.6 | 1.3 34.3 280 11 6 8.4 4.6
14000 1.8 35.2 265 10 5 8.4 4.6 | 2.5 36.5 280 11 6 8.1 4.5
13500 3.0 37.4 260 10 5 8.6 4.7 | 3.6 38.5 275 11 6 8.2 4.5
13000 4.3 39.7 260 10 5 9.0 5.0 | 4.8 40.6 270 11 6 8.4 4.6
12500 5.6 42.1 260 10 5 9.0 5.0 | 6.0 42.8 265 11 6 8.4 4.6
12000 6.9 44.4 255 9 5 9.0 5.0 | 7.3 45.1 260 11 5 8.7 4.8
11500 8.3 46.9 255 9 5 9.0 5.0 | 8.5 47.3 255 10 5 8.7 4.8
11000 9.6 49.3 255 9 5 9.0 4.9 | 9.7 49.5 255 10 5 8.1 4.5
10500 10.9 51.6 250 8 4 6.0 3.3 | 10.9 51.6 250 9 5 9.6 5.2
10250 11.2 52.2 250 8 4 6.8 3.7 | 11.7 53.1 245 10 5 10.1 5.5
10000 12.0 53.6 250 8 4 11.4 6.3 | 12.3 54.1 240 10 5 8.4 4.6
9750 12.8 55.0 245 8 4 10.2 5.6 | 12.9 55.2 240 10 5 8.6 4.7
9500 13.6 56.5 240 8 4 10.4 5.7 | 13.6 56.5 240 10 5 8.5 4.7
9250 14.3 57.7 240 7 4 8.5 4.7 | 14.2 57.6 235 10 5 8.8 4.8
9000 14.9 58.8 240 7 4 8.6 4.7 | 14.9 58.8 235 9 5 8.7 4.8
8750 15.6 60.1 235 7 4 9.7 5.3 | 15.5 59.9 230 9 5 8.3 4.6
8500 16.3 61.3 230 7 4 9.3 5.1 | 16.7 62.1 225 10 5 8.0 4.4
8250 16.9 62.4 225 7 4 8.0 4.4 | 17.3 63.1 220 10 5 8.0 4.4
8000 18.2 64.8 225 8 4 10.3 5.7 | 17.9 64.2 215 10 5 8.5 4.7
7750 19.0 66.2 220 8 4 9.6 5.3 | 18.6 65.5 215 10 5 8.1 4.4
7500 19.7 67.5 220 8 4 8.5 4.7 | 19.1 66.4 205 10 5 6.6 3.6
7250 20.3 68.5 220 8 4 8.8 4.8 | 19.6 67.3 200 10 5 6.6 3.6
7000 21.0 69.8 220 8 4 10.6 5.8 | 20.1 68.2 195 10 5 9.1 5.0
6750 21.8 71.2 215 8 4 10.6 5.8 | 20.9 69.6 195 10 5 9.8 5.4
6500 22.5 72.5 215 8 4 10.0 5.5 | 21.5 70.7 190 10 5 9.2 5.1
6250 23.3 73.9 215 8 4 9.4 5.2 | 22.2 72.0 185 10 5 9.1 5.0
6000 24.0 75.2 215 8 4 11.4 6.3 | 22.8 73.0 180 11 5 8.9 4.9
5750 25.1 77.2 210 7 4 22.2 12.2 | 23.6 74.5 185 9 5 13.6 7.5
5500 27.3 81.1 210 7 4 34.8 19.1 | 25.2 77.4 180 9 5 35.8 19.7
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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