Soaring Guidance
Issued by NWS Grand Junction, CO
Issued by NWS Grand Junction, CO
449
UXUS97 KGJT 291307
SRGGJT
Soaring Forecast
National Weather Service Grand Junction, Colorado
707 AM MDT Saturday, June 29, 2024
This forecast is for Saturday, June 29, 2024:
If the trigger temperature of 82.9 F/28.3 C is reached...then
Thermal Soaring Index....................... Excellent
Maximum rate of lift........................ 1257 ft/min (6.4 m/s)
Maximum height of thermals.................. 18728 ft MSL (13889 ft AGL)
Forecast maximum temperature................... 95.0 F/35.5 C
Time of trigger temperature.................... 1000 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................. 13037 ft MSL (8198 ft AGL)
Thermal soaring outlook for Sunday 06/30....... Excellent
Wave Soaring Index............................. Not available
Remarks...
Sunrise/Sunset.................... 05:51:21 / 20:44:15 MDT
Total possible sunshine........... 14 hr 52 min 54 sec (892 min 54 sec)
Altitude of sun at 13:17:48 MDT... 73.61 degrees
Upper air data from rawinsonde observation taken on 06/29/2024 at 0600 MDT
Freezing level.................. 15865 ft MSL (11026 ft AGL)
Convective condensation level... 14361 ft MSL (9522 ft AGL)
Lifted condensation level....... 15419 ft MSL (10580 ft AGL)
Lifted index.................... -3.6
K index......................... +23.4
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 -65.5 -85.9 280 62 32 2.9 1.6 83.6 182.5 28.3 M M
45000 -58.7 -73.7 270 70 36 3.7 2.0 70.5 158.9 22.2 M M
40000 -50.7 -59.3 260 65 34 6.2 3.4 60.2 140.4 16.8 M M
38000 -46.2 -51.2 255 52 27 7.7 4.2 58.2 136.8 15.9 M M
36000 -42.4 -44.3 260 39 20 6.2 3.4 55.2 131.4 14.2 M M
34000 -37.3 -35.1 250 28 14 7.9 4.4 53.2 127.8 13.2 M M
32000 -32.6 -26.7 235 28 14 7.5 4.1 51.6 124.9 12.3 M M
30000 -28.2 -18.8 250 32 16 7.4 4.1 49.7 121.5 11.2 M M
29000 -25.9 -14.6 255 30 15 7.8 4.3 48.8 119.9 10.6 M M
28000 -23.5 -10.3 260 26 13 9.1 5.0 48.1 118.6 10.2 M M
27000 -20.7 -5.3 260 24 12 9.6 5.3 48.0 118.3 10.2 M M
26000 -18.3 -0.9 245 21 11 7.2 3.9 47.3 117.1 9.8 M M
25000 -16.5 2.3 235 21 11 5.9 3.2 46.0 114.8 8.8 M M
24000 -14.9 5.2 230 19 10 5.8 3.2 44.5 112.1 7.6 M M
23000 -13.2 8.2 230 21 11 7.6 4.2 43.1 109.7 6.4 M M
22000 -11.4 11.5 240 20 10 8.0 4.4 41.7 107.0 5.4 M M
21000 -9.5 14.9 245 20 10 1.1 0.6 40.3 104.6 4.3 M M
20000 -9.9 14.2 255 27 14 3.5 1.9 36.8 98.2 1.1 M M
19500 -8.9 16.0 260 24 12 6.9 3.8 36.2 97.2 0.6 M M
19000 -7.8 18.0 260 23 12 7.5 4.1 35.8 96.4 0.2 M M
18500 -6.1 21.0 265 19 10 7.6 4.1 35.2 95.4 -0.2 1222 6.2
18000 -4.9 23.2 280 19 10 7.5 4.1 34.8 94.7 -0.5 1173 6.0
17500 -3.9 25.0 275 17 9 7.5 4.1 34.5 94.0 -1.0 1128 5.7
17000 -2.9 26.8 280 16 8 8.1 4.5 34.1 93.3 -1.4 1082 5.5
16500 -1.5 29.3 285 18 9 9.4 5.1 34.0 93.1 -1.6 1027 5.2
16000 -0.2 31.6 285 18 9 9.3 5.1 33.9 93.0 -1.6 971 4.9
15500 1.2 34.2 280 16 8 9.2 5.1 33.8 92.9 -1.7 915 4.6
15000 2.5 36.5 285 12 6 8.6 4.7 33.7 92.6 -1.9 861 4.4
14500 3.8 38.8 290 6 3 8.6 4.7 33.5 92.3 -2.1 807 4.1
14000 5.1 41.2 250 7 3 8.4 4.6 33.3 91.9 -2.3 754 3.8
13500 6.2 43.2 205 3 2 7.2 4.0 33.0 91.3 -2.7 707 3.6
13000 7.3 45.1 160 3 2 9.2 5.0 32.7 90.8 -3.0 659 3.3
12500 8.7 47.7 185 4 2 9.5 5.2 32.7 90.8 -3.1 602 3.1
12000 9.7 49.5 180 6 3 5.9 3.3 32.3 90.1 -3.5 556 2.8
11500 10.6 51.1 165 11 6 6.2 3.4 31.7 89.1 -4.2 516 2.6
11000 11.5 52.7 165 11 6 7.7 4.2 31.2 88.2 -4.7 473 2.4
10500 12.7 54.9 160 11 6 7.8 4.3 31.0 87.8 -5.0 422 2.1
10250 13.3 55.9 170 11 6 7.3 4.0 30.8 87.5 -5.2 397 2.0
10000 13.8 56.8 170 11 6 7.2 3.9 30.6 87.1 -5.4 374 1.9
9750 14.3 57.7 165 12 6 7.2 4.0 30.4 86.7 -5.6 351 1.8
9500 14.9 58.8 160 13 7 7.2 3.9 30.2 86.4 -5.8 328 1.7
9250 15.4 59.7 165 12 6 7.2 3.9 30.0 86.0 -6.0 305 1.6
9000 15.9 60.6 170 13 7 7.2 4.0 29.8 85.7 -6.3 283 1.4
8750 16.4 61.5 165 16 8 7.2 3.9 29.6 85.3 -6.5 260 1.3
8500 16.9 62.4 160 17 9 7.3 4.0 29.4 85.0 -6.7 237 1.2
8250 17.5 63.5 155 20 10 6.7 3.7 29.2 84.6 -6.9 214 1.1
8000 18.0 64.4 155 23 12 9.0 4.9 29.0 84.2 -7.2 191 1.0
7750 18.5 65.3 155 25 13 0.7 0.4 28.8 83.9 -7.4 168 0.9
7500 17.9 64.2 150 28 15 -13.3 -7.3 27.5 81.4 -8.8 179 0.9
7250 17.0 62.6 145 32 16 -2.2 -1.2 25.9 78.6 -10.4 197 1.0
7000 17.3 63.1 140 30 15 7.4 4.0 25.6 78.1 -10.8 181 0.9
6750 17.7 63.9 140 29 15 4.6 2.5 25.2 77.4 -11.2 161 0.8
6500 18.1 64.6 145 28 14 6.7 3.7 24.9 76.9 -11.5 141 0.7
6250 18.6 65.5 140 24 12 8.5 4.7 24.8 76.6 -11.8 120 0.6
6000 18.8 65.8 135 20 10 -6.0 -3.3 24.3 75.8 -12.3 105 0.5
5750 18.1 64.6 135 19 10 -5.1 -2.8 22.8 73.0 -13.9 122 0.6
5500 18.3 64.9 140 16 8 6.2 3.4 22.3 72.2 -14.4 106 0.5
5250 18.5 65.3 140 14 7 4.3 2.3 21.9 71.4 -14.9 93 0.5
5000 19.2 66.6 135 11 6 15.2 8.3 21.8 71.3 -15.0 66 0.3
* * * * * * Numerical weather prediction model forecast data valid * * * * * *
06/29/2024 at 0900 MDT | 06/29/2024 at 1200 MDT
|
CAPE... +299.8 LI... -2.4 | CAPE... +625.2 LI... -3.9
CINH... -102.5 K Index... +25.7 | CINH... -11.3 K Index... +29.5
|
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 -64.0 -83.2 285 45 23 2.5 1.4 | -64.2 -83.6 275 36 18 2.7 1.5
45000 -58.3 -72.9 275 56 29 6.0 3.3 | -58.2 -72.8 270 47 24 6.3 3.4
40000 -49.2 -56.6 260 59 30 6.8 3.7 | -48.1 -54.6 255 51 26 7.1 3.9
38000 -44.6 -48.3 260 52 27 6.8 3.7 | -43.8 -46.8 255 51 26 7.1 3.9
36000 -40.5 -40.9 260 46 24 6.5 3.6 | -39.6 -39.3 250 51 26 6.5 3.5
34000 -36.8 -34.2 255 38 19 6.3 3.4 | -36.0 -32.8 250 44 23 6.0 3.3
32000 -33.0 -27.4 250 30 15 6.4 3.5 | -32.4 -26.3 245 36 19 6.1 3.3
30000 -28.6 -19.5 245 27 14 7.5 4.1 | -28.5 -19.3 245 31 16 6.5 3.6
29000 -26.4 -15.5 245 26 13 7.5 4.1 | -26.5 -15.7 245 28 14 6.5 3.6
28000 -24.1 -11.4 240 25 13 7.4 4.0 | -24.5 -12.1 245 25 13 7.1 3.9
27000 -21.9 -7.4 245 24 12 7.4 4.0 | -22.3 -8.1 245 24 12 7.2 4.0
26000 -19.7 -3.5 250 23 12 7.4 4.0 | -20.2 -4.4 245 23 12 7.2 4.0
25000 -17.5 0.5 250 22 11 7.2 4.0 | -17.5 0.5 245 22 11 6.9 3.8
24000 -15.6 3.9 250 21 11 6.1 3.3 | -15.5 4.1 245 21 11 6.8 3.7
23000 -13.4 7.9 245 21 11 6.1 3.4 | -13.4 7.9 240 21 11 6.8 3.7
22000 -11.6 11.1 245 20 11 5.4 3.0 | -11.5 11.3 235 21 11 4.9 2.7
21000 -10.1 13.8 240 19 10 5.3 2.9 | -10.2 13.6 230 20 11 4.8 2.6
20000 -8.6 16.5 235 18 9 5.5 3.0 | -8.8 16.2 230 20 10 5.1 2.8
19500 -7.9 17.8 235 17 9 6.0 3.3 | -8.2 17.2 230 20 10 6.1 3.3
19000 -6.9 19.6 235 17 9 7.0 3.8 | -7.1 19.2 230 19 10 7.8 4.3
18500 -5.9 21.4 230 16 8 6.9 3.8 | -6.0 21.2 230 19 10 7.9 4.3
18000 -4.9 23.2 230 15 8 7.6 4.1 | -4.9 23.2 230 19 10 7.9 4.3
17500 -3.7 25.3 230 14 7 7.7 4.2 | -3.8 25.2 230 19 10 7.9 4.3
17000 -2.6 27.3 230 14 7 7.8 4.3 | -2.7 27.1 230 19 10 8.1 4.4
16500 -1.5 29.3 230 13 7 8.2 4.5 | -1.4 29.5 230 18 9 8.4 4.6
16000 -0.3 31.5 230 12 6 8.1 4.5 | -0.2 31.6 230 18 9 8.4 4.6
15500 0.9 33.6 230 12 6 8.7 4.8 | 1.1 34.0 230 17 9 9.3 5.1
15000 2.2 36.0 225 11 6 8.7 4.7 | 2.4 36.3 225 16 8 9.2 5.1
14500 3.4 38.1 225 11 6 8.9 4.9 | 3.7 38.7 225 15 8 9.1 5.0
14000 4.7 40.5 225 10 5 9.0 4.9 | 5.0 41.0 220 13 7 9.1 5.0
13500 6.0 42.8 225 10 5 9.1 5.0 | 6.4 43.5 220 12 6 9.1 5.0
13000 7.4 45.3 220 9 5 9.1 5.0 | 7.7 45.9 215 12 6 9.1 5.0
12500 8.7 47.7 220 8 4 9.1 5.0 | 9.0 48.2 215 11 6 9.1 5.0
12000 10.0 50.0 220 8 4 8.8 4.8 | 10.4 50.7 210 10 5 9.1 5.0
11500 11.3 52.3 215 8 4 8.7 4.8 | 11.7 53.1 210 10 5 9.1 5.0
11000 12.5 54.5 215 8 4 8.0 4.4 | 13.0 55.4 205 9 5 8.6 4.7
10500 13.7 56.7 210 8 4 5.5 3.0 | 14.3 57.7 205 9 5 6.6 3.6
10250 14.0 57.2 210 8 4 5.5 3.0 | 14.7 58.5 205 9 5 7.2 4.0
10000 14.6 58.3 205 8 4 8.9 4.9 | 15.4 59.7 200 9 5 10.4 5.7
9750 15.2 59.4 200 9 4 8.1 4.4 | 16.1 61.0 200 9 4 9.7 5.3
9500 15.8 60.4 195 9 5 8.1 4.5 | 16.8 62.2 200 8 4 9.4 5.1
9250 16.3 61.3 190 9 5 6.8 3.7 | 17.5 63.5 195 8 4 8.3 4.6
9000 16.8 62.2 185 10 5 6.1 3.3 | 18.1 64.6 190 8 4 8.7 4.7
8750 17.2 63.0 180 10 5 6.3 3.5 | 19.4 66.9 190 7 4 8.5 4.6
8500 18.0 64.4 170 12 6 4.9 2.7 | 19.9 67.8 185 7 4 6.4 3.5
8250 18.4 65.1 165 13 7 4.5 2.5 | 20.4 68.7 180 7 4 8.4 4.6
8000 18.7 65.7 160 13 7 4.8 2.6 | 21.2 70.2 180 7 3 11.3 6.2
7750 19.0 66.2 155 12 6 3.9 2.1 | 21.9 71.4 180 6 3 9.5 5.2
7500 19.2 66.6 155 12 6 2.3 1.3 | 22.5 72.5 180 6 3 7.8 4.3
7250 19.3 66.7 150 13 7 3.0 1.7 | 23.1 73.6 175 6 3 9.0 4.9
7000 19.7 67.5 150 12 6 6.8 3.7 | 23.9 75.0 175 6 3 12.3 6.8
6750 20.2 68.4 145 10 5 7.5 4.1 | 24.9 76.8 180 5 3 11.6 6.4
6500 20.6 69.1 145 9 5 6.3 3.4 | 25.6 78.1 175 6 3 10.2 5.6
6250 21.1 70.0 145 9 5 6.0 3.3 | 26.4 79.5 170 6 3 9.4 5.2
6000 21.6 70.9 140 9 5 10.7 5.9 | 27.2 81.0 165 6 3 13.0 7.1
5750 22.7 72.9 140 7 4 21.2 11.6 | 28.5 83.3 170 5 2 26.2 14.4
5500 24.0 75.2 135 7 4 6.0 3.3 | 30.6 87.1 160 5 3 24.1 13.2
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
06/29/2024 at 1500 MDT | 06/29/2024 at 1800 MDT
|
CAPE... +602.7 LI... -3.5 | CAPE... +402.6 LI... -2.8
CINH... -9.8 K Index... +31.0 | CINH... -12.1 K Index... +31.7
|
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 -64.3 -83.7 260 32 17 3.3 1.8 | -64.2 -83.6 250 30 16 3.7 2.0
45000 -57.5 -71.5 260 41 21 5.9 3.2 | -57.1 -70.8 245 38 20 5.7 3.1
40000 -48.3 -54.9 250 45 23 7.1 3.9 | -48.2 -54.8 245 43 22 6.9 3.8
38000 -44.1 -47.4 245 47 24 7.1 3.9 | -44.1 -47.4 240 48 25 6.9 3.8
36000 -39.9 -39.8 245 49 25 7.0 3.8 | -39.9 -39.8 235 52 27 7.1 3.9
34000 -35.7 -32.3 245 48 25 7.0 3.8 | -35.6 -32.1 240 50 26 7.2 4.0
32000 -31.5 -24.7 245 47 24 7.0 3.9 | -31.2 -24.2 240 47 24 7.5 4.1
30000 -28.0 -18.4 240 36 19 5.6 3.1 | -27.2 -17.0 240 40 21 6.6 3.6
29000 -26.3 -15.3 235 30 16 5.6 3.1 | -25.3 -13.5 235 36 19 6.6 3.6
28000 -24.5 -12.1 230 25 13 7.3 4.0 | -23.3 -9.9 235 32 17 6.2 3.4
27000 -21.7 -7.1 230 24 12 7.5 4.1 | -21.0 -5.8 235 28 14 6.2 3.4
26000 -19.5 -3.1 230 23 12 7.5 4.1 | -19.1 -2.4 230 24 12 6.2 3.4
25000 -17.2 1.0 230 22 11 7.0 3.8 | -17.3 0.9 230 21 11 6.8 3.8
24000 -15.2 4.6 230 21 11 6.9 3.8 | -15.2 4.6 225 20 11 7.0 3.8
23000 -13.2 8.2 225 21 11 7.0 3.8 | -13.1 8.4 225 20 10 7.0 3.8
22000 -11.2 11.8 220 21 11 5.7 3.1 | -11.1 12.0 225 20 10 5.9 3.3
21000 -9.6 14.7 215 20 10 5.7 3.1 | -9.5 14.9 220 19 10 6.0 3.3
20000 -8.0 17.6 210 19 10 5.8 3.2 | -7.8 18.0 215 19 10 6.2 3.4
19500 -7.2 19.0 205 19 10 6.4 3.5 | -7.0 19.4 210 19 10 6.7 3.7
19000 -6.2 20.8 205 18 9 7.3 4.0 | -5.9 21.4 210 18 9 7.6 4.2
18500 -5.2 22.6 200 18 9 7.3 4.0 | -4.8 23.4 210 18 9 7.6 4.2
18000 -4.1 24.6 200 17 9 8.1 4.5 | -3.7 25.3 210 18 9 7.8 4.3
17500 -2.9 26.8 205 17 9 8.2 4.5 | -2.6 27.3 210 18 9 7.9 4.3
17000 -1.7 28.9 205 17 9 8.3 4.5 | -1.5 29.3 210 18 9 8.0 4.4
16500 -0.5 31.1 205 16 8 8.4 4.6 | -0.3 31.5 215 17 9 8.2 4.5
16000 0.7 33.3 205 16 8 8.4 4.6 | 0.9 33.6 215 16 8 8.2 4.5
15500 2.0 35.6 205 15 8 8.5 4.7 | 2.1 35.8 215 16 8 8.6 4.7
15000 3.2 37.8 210 14 7 8.5 4.7 | 3.4 38.1 215 15 8 8.6 4.7
14500 4.5 40.1 210 14 7 8.9 4.9 | 4.7 40.5 215 14 7 9.0 5.0
14000 5.8 42.4 210 13 7 9.0 5.0 | 6.0 42.8 215 13 7 9.2 5.0
13500 7.1 44.8 215 13 6 9.2 5.0 | 7.3 45.1 215 13 7 9.4 5.1
13000 8.5 47.3 215 12 6 9.3 5.1 | 8.8 47.8 220 12 6 9.6 5.2
12500 9.9 49.8 215 12 6 9.3 5.1 | 10.2 50.4 220 12 6 9.6 5.3
12000 11.3 52.3 220 11 6 9.4 5.1 | 11.6 52.9 220 12 6 9.7 5.3
11500 12.6 54.7 220 11 5 9.3 5.1 | 13.1 55.6 220 11 6 9.5 5.2
11000 14.0 57.2 225 10 5 9.0 4.9 | 14.4 57.9 225 11 5 8.9 4.9
10500 15.4 59.7 225 10 5 7.2 4.0 | 15.7 60.3 225 10 5 10.9 6.0
10250 15.8 60.4 230 9 4 7.9 4.3 | 16.6 61.9 225 10 5 11.2 6.2
10000 16.6 61.9 230 9 4 10.8 5.9 | 17.3 63.1 230 9 5 8.8 4.8
9750 17.3 63.1 230 9 4 10.2 5.6 | 18.0 64.4 230 9 5 9.4 5.1
9500 18.1 64.6 230 9 4 9.9 5.4 | 19.4 66.9 230 8 4 9.6 5.3
9250 18.8 65.8 235 8 4 9.1 5.0 | 20.1 68.2 235 7 4 8.9 4.9
9000 20.1 68.2 240 8 4 9.7 5.3 | 20.8 69.4 235 7 4 8.7 4.8
8750 20.8 69.4 240 8 4 9.2 5.1 | 21.4 70.5 235 7 3 8.7 4.8
8500 21.5 70.7 245 8 4 7.5 4.1 | 22.0 71.6 235 6 3 8.3 4.6
8250 22.0 71.6 250 7 4 9.2 5.0 | 22.7 72.9 235 6 3 8.9 4.9
8000 22.8 73.0 250 7 4 11.8 6.5 | 23.4 74.1 235 6 3 9.7 5.3
7750 23.6 74.5 245 8 4 9.8 5.4 | 24.1 75.4 235 5 3 8.9 4.9
7500 24.2 75.6 250 7 4 7.6 4.2 | 24.7 76.5 235 5 3 7.8 4.3
7250 24.8 76.6 255 7 4 8.7 4.8 | 25.2 77.4 235 5 2 8.4 4.6
7000 25.6 78.1 255 7 4 12.2 6.7 | 25.9 78.6 235 4 2 10.4 5.7
6750 26.5 79.7 250 7 4 11.5 6.3 | 26.7 80.1 230 4 2 10.7 5.9
6500 27.3 81.1 255 7 4 9.8 5.4 | 27.5 81.5 230 4 2 10.3 5.7
6250 28.0 82.4 265 7 3 9.5 5.2 | 28.2 82.8 230 3 2 10.0 5.5
6000 28.8 83.8 265 7 3 11.7 6.4 | 29.0 84.2 230 3 2 9.6 5.2
5750 29.9 85.8 260 7 3 21.2 11.6 | 29.7 85.5 230 3 2 13.7 7.5
5500 31.7 89.1 270 6 3 25.7 14.1 | 31.2 88.2 230 2 1 28.9 15.9
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
________________________________________________________________________________
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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