Soaring Guidance
Issued by NWS Grand Junction, CO
Issued by NWS Grand Junction, CO
447
UXUS97 KGJT 301307
SRGGJT
Soaring Forecast
National Weather Service Grand Junction, Colorado
707 AM MDT Thursday, May 30, 2024
This forecast is for Thursday, May 30, 2024:
If the trigger temperature of 73.0 F/22.8 C is reached...then
Thermal Soaring Index....................... Excellent
Maximum rate of lift........................ 1256 ft/min (6.4 m/s)
Maximum height of thermals.................. 18935 ft MSL (14096 ft AGL)
Forecast maximum temperature................... 87.0 F/31.0 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................. 14952 ft MSL (10113 ft AGL)
Thermal soaring outlook for Friday 05/31....... Excellent
Wave Soaring Index............................. Not available
Remarks...
Sunrise/Sunset.................... 05:50:28 / 20:33:09 MDT
Total possible sunshine........... 14 hr 42 min 41 sec (882 min 41 sec)
Altitude of sun at 13:11:49 MDT... 72.63 degrees
Upper air data from rawinsonde observation taken on 05/30/2024 at 0600 MDT
Freezing level.................. 13709 ft MSL (8870 ft AGL)
Convective condensation level... 16050 ft MSL (11211 ft AGL)
Lifted condensation level....... 17209 ft MSL (12370 ft AGL)
Lifted index.................... -3.7
K index......................... +14.8
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 -54.3 -65.7 255 42 22 0.2 0.1 108.1 226.6 44.5 M M
45000 -55.6 -68.1 250 37 19 2.6 1.4 81.2 178.1 31.1 M M
40000 -56.3 -69.3 275 29 15 1.9 1.0 55.9 132.7 16.7 M M
38000 -57.5 -71.5 260 30 15 1.2 0.7 45.4 113.7 10.0 M M
36000 -53.4 -64.1 265 27 14 5.6 3.1 42.8 109.0 8.5 M M
34000 -49.4 -56.9 295 26 13 8.3 4.6 40.3 104.5 6.9 M M
32000 -44.5 -48.1 290 22 12 6.4 3.5 38.9 102.1 6.1 M M
30000 -40.0 -40.0 290 29 15 8.8 4.8 36.2 97.1 4.2 M M
29000 -37.3 -35.1 280 29 15 9.0 5.0 35.9 96.7 4.1 M M
28000 -34.9 -30.8 270 26 13 6.1 3.3 35.2 95.4 3.6 M M
27000 -32.5 -26.5 265 19 10 8.8 4.8 34.6 94.2 3.1 M M
26000 -29.9 -21.8 270 19 10 8.8 4.9 34.2 93.6 2.9 M M
25000 -27.2 -17.0 275 20 10 8.8 4.8 33.9 93.0 2.6 M M
24000 -24.8 -12.6 270 20 10 7.8 4.3 33.3 92.0 2.2 M M
23000 -22.1 -7.8 240 24 12 7.6 4.2 33.0 91.4 2.0 M M
22000 -19.7 -3.5 255 26 13 9.1 5.0 32.5 90.5 1.5 M M
21000 -16.9 1.6 250 24 12 9.0 5.0 32.3 90.1 1.3 M M
20000 -14.5 5.9 260 24 12 8.2 4.5 31.8 89.2 0.9 M M
19500 -13.2 8.2 265 23 12 8.0 4.4 31.5 88.8 0.7 M M
19000 -12.0 10.4 260 22 11 4.5 2.5 31.3 88.3 0.4 M M
18500 -11.9 10.6 260 27 14 4.2 2.3 29.8 85.6 -1.0 1243 6.3
18000 -10.9 12.4 260 28 14 8.0 4.4 29.3 84.7 -1.4 1198 6.1
17500 -9.6 14.7 265 25 13 8.4 4.6 29.0 84.2 -1.6 1145 5.8
17000 -8.3 17.1 275 22 12 8.5 4.7 28.8 83.9 -1.7 1091 5.5
16500 -6.5 20.3 285 24 13 8.1 4.4 28.4 83.1 -2.1 1014 5.2
16000 -5.3 22.5 290 26 14 8.1 4.5 28.1 82.7 -2.4 964 4.9
15500 -4.2 24.4 295 28 14 8.2 4.5 27.9 82.2 -2.7 915 4.6
15000 -3.0 26.6 295 28 15 8.3 4.5 27.6 81.7 -3.0 865 4.4
14500 -1.8 28.8 290 26 14 8.3 4.5 27.4 81.3 -3.3 813 4.1
14000 -0.5 31.1 295 22 11 8.3 4.6 27.1 80.8 -3.5 762 3.9
13500 0.7 33.3 290 21 11 8.4 4.6 26.9 80.4 -3.8 710 3.6
13000 1.9 35.4 290 22 11 8.5 4.7 26.7 80.1 -4.0 658 3.3
12500 3.2 37.8 290 22 11 8.4 4.6 26.5 79.7 -4.2 606 3.1
12000 4.4 39.9 295 23 12 5.6 3.1 26.3 79.3 -4.5 554 2.8
11500 5.0 41.0 300 21 11 3.2 1.8 25.2 77.4 -5.4 523 2.7
11000 5.6 42.1 310 18 9 5.9 3.3 24.3 75.7 -6.3 490 2.5
10500 6.7 44.1 325 16 8 8.6 4.7 23.9 75.0 -6.7 443 2.2
10250 7.3 45.1 330 15 8 9.2 5.1 23.9 74.9 -6.8 416 2.1
10000 7.9 46.2 335 13 7 9.1 5.0 23.8 74.9 -6.9 390 2.0
9750 8.6 47.5 330 13 7 8.9 4.9 23.8 74.8 -7.0 363 1.8
9500 9.2 48.6 325 13 7 8.6 4.7 23.7 74.6 -7.1 337 1.7
9250 9.8 49.6 320 13 7 8.7 4.8 23.6 74.5 -7.2 310 1.6
9000 10.5 50.9 320 10 5 8.6 4.7 23.5 74.3 -7.4 284 1.4
8750 11.1 52.0 315 10 5 8.9 4.9 23.4 74.2 -7.5 257 1.3
8500 11.8 53.2 315 10 5 9.4 5.2 23.4 74.1 -7.6 230 1.2
8250 12.4 54.3 315 9 5 9.7 5.3 23.4 74.1 -7.6 203 1.0
8000 13.1 55.6 340 8 4 9.6 5.3 23.4 74.0 -7.7 175 0.9
7750 13.8 56.8 340 7 4 9.0 5.0 23.3 74.0 -7.8 148 0.8
7500 14.4 57.9 345 6 3 8.6 4.7 23.3 73.9 -7.9 122 0.6
7250 15.1 59.2 360 6 3 8.8 4.8 23.2 73.7 -8.0 95 0.5
7000 15.7 60.3 015 7 4 8.7 4.8 23.1 73.6 -8.1 69 0.3
6750 16.3 61.3 020 9 4 8.7 4.8 23.0 73.4 -8.2 42 0.2
6500 17.0 62.6 030 10 5 8.9 4.9 22.9 73.3 -8.4 16 0.1
6250 17.6 63.7 030 12 6 8.3 4.6 22.9 73.2 -8.5 M M
6000 18.1 64.6 035 14 7 5.8 3.2 22.7 72.8 -8.7 M M
5750 18.5 65.3 035 13 7 4.5 2.5 22.3 72.1 -9.1 M M
5500 18.8 65.8 035 12 6 4.7 2.6 21.9 71.5 -9.5 M M
5250 19.1 66.4 045 10 5 5.3 2.9 21.6 70.8 -10.0 M M
5000 19.4 66.9 035 10 5 1.7 0.9 21.1 70.1 -10.4 M M
* * * * * * Numerical weather prediction model forecast data valid * * * * * *
05/30/2024 at 0900 MDT | 05/30/2024 at 1200 MDT
|
CAPE... 0.0 LI... +1.5 | CAPE... +2.1 LI... +1.1
CINH... -0.3 K Index... +14.3 | CINH... -19.3 K Index... +15.7
|
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 -54.6 -66.3 265 28 15 -0.1 -0.1 | -55.4 -67.7 260 28 14 0.1 0.1
45000 -55.1 -67.2 265 36 19 -1.6 -0.9 | -55.6 -68.1 270 35 18 -2.1 -1.2
40000 -57.5 -71.5 295 24 12 -1.4 -0.8 | -58.9 -74.0 305 26 13 -2.2 -1.2
38000 -55.7 -68.3 300 23 12 3.8 2.1 | -56.3 -69.3 305 24 13 5.2 2.9
36000 -53.5 -64.3 300 24 12 3.8 2.1 | -53.2 -63.8 300 23 12 5.2 2.9
34000 -49.9 -57.8 300 24 12 8.1 4.5 | -49.1 -56.4 295 22 12 8.1 4.4
32000 -45.0 -49.0 295 24 12 8.1 4.5 | -44.3 -47.7 290 22 12 8.1 4.4
30000 -40.1 -40.2 290 23 12 8.2 4.5 | -39.5 -39.1 285 23 12 8.0 4.4
29000 -37.6 -35.7 285 23 12 8.2 4.5 | -37.1 -34.8 285 24 12 8.0 4.4
28000 -35.1 -31.2 280 23 12 8.2 4.5 | -34.7 -30.5 285 24 12 8.0 4.4
27000 -32.7 -26.9 280 23 12 7.9 4.4 | -32.3 -26.1 280 25 13 8.1 4.4
26000 -30.3 -22.5 285 23 12 7.9 4.3 | -29.8 -21.6 280 26 13 8.1 4.4
25000 -28.0 -18.4 285 24 12 7.9 4.3 | -27.4 -17.3 280 26 14 8.1 4.4
24000 -25.0 -13.0 285 25 13 8.2 4.5 | -24.4 -11.9 280 27 14 8.1 4.4
23000 -22.5 -8.5 280 26 13 8.2 4.5 | -22.0 -7.6 280 27 14 8.1 4.4
22000 -20.1 -4.2 280 27 14 8.3 4.5 | -19.6 -3.3 280 27 14 8.2 4.5
21000 -17.8 -0.0 275 27 14 7.6 4.2 | -17.3 0.9 280 26 14 7.4 4.0
20000 -15.5 4.1 270 26 13 7.6 4.2 | -15.1 4.8 275 25 13 7.4 4.1
19500 -14.4 6.1 265 26 13 7.7 4.2 | -14.0 6.8 270 25 13 7.4 4.1
19000 -13.3 8.1 260 26 13 7.8 4.3 | -12.9 8.8 270 24 12 7.6 4.2
18500 -12.1 10.2 260 26 13 7.9 4.3 | -11.8 10.8 265 24 12 7.8 4.3
18000 -10.9 12.4 260 25 13 7.9 4.3 | -10.6 12.9 260 23 12 7.8 4.3
17500 -9.8 14.4 260 25 13 8.2 4.5 | -9.5 14.9 260 23 12 7.9 4.3
17000 -8.6 16.5 260 24 12 8.2 4.5 | -8.3 17.1 255 22 12 7.9 4.3
16500 -7.4 18.7 260 24 12 8.2 4.5 | -7.2 19.0 255 22 11 7.9 4.3
16000 -6.1 21.0 265 23 12 8.2 4.5 | -6.0 21.2 255 21 11 7.9 4.4
15500 -4.9 23.2 265 22 12 8.2 4.5 | -4.8 23.4 255 21 11 7.9 4.3
15000 -3.7 25.3 265 22 11 8.1 4.4 | -3.7 25.3 255 20 10 7.7 4.2
14500 -2.5 27.5 270 21 11 8.0 4.4 | -2.6 27.3 255 19 10 7.7 4.3
14000 -1.4 29.5 270 20 11 7.3 4.0 | -1.4 29.5 255 19 10 7.8 4.3
13500 -0.3 31.5 275 20 10 7.4 4.0 | -0.3 31.5 255 18 9 7.9 4.3
13000 0.7 33.3 275 19 10 7.5 4.1 | 0.8 33.4 255 17 9 7.6 4.2
12500 1.9 35.4 280 18 9 7.6 4.1 | 2.0 35.6 255 15 8 7.6 4.2
12000 2.9 37.2 280 17 9 7.0 3.9 | 3.1 37.6 255 14 7 7.9 4.4
11500 4.0 39.2 285 15 8 7.2 3.9 | 4.2 39.6 255 13 7 8.0 4.4
11000 4.9 40.8 285 13 7 5.1 2.8 | 5.4 41.7 255 12 6 7.5 4.1
10500 5.7 42.3 290 10 5 5.3 2.9 | 6.5 43.7 255 11 6 7.0 3.8
10250 6.0 42.8 290 9 4 3.6 2.0 | 7.1 44.8 255 10 5 9.7 5.3
10000 6.2 43.2 290 8 4 5.1 2.8 | 7.9 46.2 260 9 5 9.8 5.4
9750 6.8 44.2 290 6 3 7.8 4.3 | 8.4 47.1 265 9 4 7.1 3.9
9500 7.3 45.1 295 4 2 7.0 3.8 | 9.0 48.2 265 8 4 8.1 4.4
9250 7.8 46.0 305 2 1 7.6 4.2 | 9.6 49.3 265 7 4 7.0 3.8
9000 8.4 47.1 325 2 1 7.5 4.1 | 10.1 50.2 270 6 3 7.8 4.3
8750 9.4 48.9 050 2 1 7.4 4.1 | 11.4 52.5 275 6 3 9.0 4.9
8500 9.9 49.8 065 3 2 6.6 3.6 | 12.1 53.8 280 5 3 7.2 3.9
8250 10.4 50.7 060 4 2 6.5 3.6 | 12.5 54.5 280 5 3 7.8 4.3
8000 10.9 51.6 055 4 2 8.1 4.4 | 13.3 55.9 285 5 3 11.5 6.3
7750 11.5 52.7 050 5 3 7.7 4.2 | 14.1 57.4 285 5 3 11.0 6.0
7500 11.9 53.4 045 5 3 5.4 3.0 | 14.9 58.8 290 5 3 8.2 4.5
7250 12.3 54.1 045 6 3 4.7 2.6 | 15.4 59.7 290 5 3 7.7 4.2
7000 12.8 55.0 040 6 3 9.0 5.0 | 16.1 61.0 290 5 2 12.4 6.8
6750 13.5 56.3 035 5 3 10.5 5.7 | 17.2 63.0 290 5 2 12.6 6.9
6500 14.2 57.6 035 5 3 8.7 4.8 | 17.9 64.2 295 5 2 9.9 5.4
6250 14.9 58.8 035 6 3 8.5 4.7 | 18.7 65.7 295 5 2 9.5 5.2
6000 15.5 59.9 035 6 3 10.7 5.9 | 19.4 66.9 295 4 2 12.3 6.7
5750 16.6 61.9 035 5 2 19.3 10.6 | 20.7 69.3 295 4 2 24.6 13.5
5500 18.2 64.8 035 5 3 21.1 11.6 | 23.1 73.6 300 4 2 37.0 20.3
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
05/30/2024 at 1500 MDT | 05/30/2024 at 1800 MDT
|
CAPE... +36.2 LI... +0.8 | CAPE... +12.3 LI... +1.4
CINH... -32.3 K Index... +17.7 | CINH... -33.2 K Index... +8.1
|
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 -55.7 -68.3 255 28 15 -0.1 -0.1 | -55.9 -68.6 265 29 15 -0.5 -0.3
45000 -56.2 -69.2 270 33 17 -2.3 -1.2 | -56.9 -70.4 280 33 17 -1.9 -1.0
40000 -59.6 -75.3 290 33 17 -2.6 -1.4 | -59.8 -75.6 285 33 17 -2.4 -1.3
38000 -56.3 -69.3 285 31 16 6.4 3.5 | -56.3 -69.3 280 33 17 6.5 3.6
36000 -52.5 -62.5 280 29 15 6.4 3.5 | -52.4 -62.3 280 33 17 6.5 3.6
34000 -48.2 -54.8 275 28 14 7.9 4.3 | -48.0 -54.4 275 31 16 7.9 4.4
32000 -43.4 -46.1 275 26 14 7.9 4.3 | -43.3 -45.9 275 28 15 7.9 4.4
30000 -38.7 -37.7 275 26 13 7.8 4.3 | -38.5 -37.3 275 27 14 7.9 4.3
29000 -36.4 -33.5 275 26 13 7.8 4.3 | -36.1 -33.0 275 26 14 7.9 4.3
28000 -34.1 -29.4 275 26 13 7.8 4.3 | -33.8 -28.8 270 26 13 7.9 4.3
27000 -31.8 -25.2 275 27 14 7.4 4.1 | -31.5 -24.7 270 26 14 7.4 4.1
26000 -29.6 -21.3 275 28 14 7.4 4.1 | -29.3 -20.7 270 27 14 7.4 4.1
25000 -27.4 -17.3 275 29 15 7.4 4.1 | -27.0 -16.6 270 28 14 7.4 4.1
24000 -24.5 -12.1 270 29 15 8.0 4.4 | -24.8 -12.6 270 28 14 7.6 4.2
23000 -22.1 -7.8 270 28 14 8.0 4.4 | -22.0 -7.6 270 27 14 7.6 4.2
22000 -19.7 -3.5 270 26 13 8.0 4.4 | -19.7 -3.5 265 26 14 7.5 4.1
21000 -17.3 0.9 270 24 13 8.2 4.5 | -17.3 0.9 265 25 13 8.4 4.6
20000 -14.8 5.4 265 23 12 8.2 4.5 | -14.8 5.4 265 23 12 8.4 4.6
19500 -13.6 7.5 265 22 11 8.2 4.5 | -13.5 7.7 260 22 11 8.4 4.6
19000 -12.4 9.7 260 21 11 7.6 4.2 | -12.3 9.9 260 21 11 8.4 4.6
18500 -11.3 11.7 260 21 11 7.4 4.1 | -11.0 12.2 260 21 11 8.4 4.6
18000 -10.2 13.6 255 21 11 7.4 4.1 | -9.8 14.4 260 20 10 8.4 4.6
17500 -9.1 15.6 250 20 10 7.5 4.1 | -8.5 16.7 260 19 10 8.3 4.6
17000 -8.0 17.6 250 20 10 7.5 4.1 | -7.3 18.9 260 19 10 8.3 4.6
16500 -6.9 19.6 245 20 10 8.2 4.5 | -6.1 21.0 260 18 9 8.4 4.6
16000 -5.7 21.7 245 20 10 8.3 4.6 | -4.8 23.4 260 18 9 8.5 4.6
15500 -4.5 23.9 245 19 10 8.4 4.6 | -3.6 25.5 260 18 9 8.5 4.7
15000 -3.3 26.1 245 19 10 8.5 4.7 | -2.3 27.9 260 18 9 8.6 4.7
14500 -2.0 28.4 245 18 9 8.6 4.7 | -1.0 30.2 265 18 9 8.6 4.7
14000 -0.8 30.6 250 18 9 9.0 4.9 | 0.3 32.5 265 17 9 8.8 4.8
13500 0.6 33.1 250 17 9 8.9 4.9 | 1.6 34.9 265 17 9 8.7 4.8
13000 1.9 35.4 250 17 9 8.9 4.9 | 2.9 37.2 265 17 9 9.0 4.9
12500 3.2 37.8 255 16 8 8.9 4.9 | 4.2 39.6 265 17 9 9.0 4.9
12000 4.5 40.1 255 16 8 9.1 5.0 | 5.6 42.1 265 17 9 9.1 5.0
11500 5.9 42.6 255 15 8 9.2 5.1 | 6.9 44.4 265 16 8 9.2 5.0
11000 7.2 45.0 260 15 8 8.1 4.5 | 8.2 46.8 270 16 8 7.7 4.2
10500 8.4 47.1 265 15 8 7.6 4.2 | 9.3 48.7 270 16 8 7.5 4.1
10250 9.0 48.2 265 15 8 10.3 5.6 | 9.9 49.8 270 16 8 12.4 6.8
10000 9.9 49.8 265 14 7 10.6 5.8 | 11.0 51.8 270 15 8 12.3 6.8
9750 10.5 50.9 270 14 7 8.2 4.5 | 11.7 53.1 270 15 8 8.2 4.5
9500 11.2 52.2 270 14 7 8.9 4.9 | 12.4 54.3 270 15 8 10.0 5.5
9250 11.8 53.2 270 13 7 8.5 4.7 | 13.0 55.4 270 15 8 7.0 3.9
9000 12.4 54.3 275 13 7 9.0 4.9 | 13.5 56.3 270 14 7 7.8 4.3
8750 13.1 55.6 275 13 7 9.4 5.2 | 14.2 57.6 270 14 7 10.8 5.9
8500 14.5 58.1 280 12 6 8.6 4.7 | 15.0 59.0 270 14 7 10.3 5.6
8250 15.2 59.4 280 13 7 9.2 5.1 | 16.4 61.5 270 14 7 9.4 5.1
8000 15.9 60.6 280 12 6 11.1 6.1 | 17.2 63.0 270 14 7 10.7 5.8
7750 16.8 62.2 280 12 6 10.7 5.9 | 18.0 64.4 270 13 7 10.5 5.8
7500 17.5 63.5 280 12 6 8.5 4.7 | 18.7 65.7 270 13 7 8.5 4.7
7250 18.1 64.6 285 12 6 8.0 4.4 | 19.3 66.7 270 14 7 7.9 4.3
7000 18.8 65.8 285 12 6 11.8 6.5 | 20.0 68.0 270 13 7 10.7 5.9
6750 19.8 67.6 285 12 6 12.3 6.8 | 20.8 69.4 270 13 7 11.5 6.3
6500 20.6 69.1 285 11 6 10.5 5.8 | 21.6 70.9 270 13 6 10.6 5.8
6250 21.4 70.5 290 11 6 10.3 5.6 | 22.4 72.3 270 13 7 10.8 5.9
6000 22.1 71.8 290 11 6 10.6 5.8 | 23.2 73.8 270 13 7 8.7 4.8
5750 23.2 73.8 285 10 5 20.4 11.2 | 23.8 74.8 270 11 6 11.2 6.1
5500 25.9 78.6 295 10 5 61.6 33.8 | 25.8 78.4 270 11 5 53.3 29.3
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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