Soaring Guidance
Issued by NWS Grand Junction, CO
Issued by NWS Grand Junction, CO
625
UXUS97 KGJT 041307
SRGGJT
Soaring Forecast
National Weather Service Grand Junction, Colorado
707 AM MDT Tuesday, June 4, 2024
This forecast is for Tuesday, June 4, 2024:
If the trigger temperature of 74.3 F/23.5 C is reached...then
Thermal Soaring Index....................... Excellent
Maximum rate of lift........................ 1104 ft/min (5.6 m/s)
Maximum height of thermals.................. 17877 ft MSL (13038 ft AGL)
Forecast maximum temperature................... 90.0 F/32.7 C
Time of trigger temperature.................... 0930 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................. 16290 ft MSL (11451 ft AGL)
Thermal soaring outlook for Wednesday 06/05.... Excellent
Wave Soaring Index............................. Not available
Remarks...
Sunrise/Sunset.................... 05:48:43 / 20:36:32 MDT
Total possible sunshine........... 14 hr 47 min 49 sec (887 min 49 sec)
Altitude of sun at 13:12:37 MDT... 73.22 degrees
Upper air data from rawinsonde observation taken on 06/04/2024 at 0600 MDT
Freezing level.................. 13541 ft MSL (8702 ft AGL)
Convective condensation level... 13997 ft MSL (9158 ft AGL)
Lifted condensation level....... 16374 ft MSL (11535 ft AGL)
Lifted index.................... -1.8
K index......................... +22.7
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 -62.0 -79.6 310 44 22 -3.2 -1.8 93.5 200.2 35.3 M M
45000 -56.0 -68.8 320 49 25 -3.0 -1.7 77.5 171.6 28.1 M M
40000 -57.5 -71.5 345 81 42 8.3 4.5 52.2 126.0 13.3 M M
38000 -51.9 -61.4 345 87 45 9.3 5.1 51.9 125.5 13.4 M M
36000 -46.8 -52.2 325 69 35 8.2 4.5 50.8 123.5 13.0 M M
34000 -41.8 -43.2 320 67 34 7.1 3.9 49.6 121.3 12.5 M M
32000 -36.7 -34.1 315 66 34 8.5 4.7 47.5 117.5 11.2 M M
30000 -31.5 -24.7 320 66 34 8.9 4.9 46.7 116.0 10.9 M M
29000 -29.0 -20.2 325 65 33 5.0 2.8 46.0 114.9 10.6 M M
28000 -27.6 -17.7 320 63 32 4.9 2.7 44.1 111.4 9.2 M M
27000 -26.2 -15.2 320 56 29 5.8 3.2 42.2 108.0 7.7 M M
26000 -24.1 -11.4 315 47 24 8.5 4.7 41.3 106.3 7.1 M M
25000 -21.5 -6.7 305 49 25 8.6 4.7 40.8 105.5 6.8 M M
24000 -19.0 -2.2 310 48 25 8.4 4.6 40.4 104.6 6.5 M M
23000 -16.9 1.6 310 40 21 3.3 1.8 39.4 102.9 5.7 M M
22000 -16.0 3.2 305 33 17 5.7 3.1 37.0 98.6 3.8 M M
21000 -14.2 6.4 295 38 19 6.3 3.4 35.7 96.2 2.6 M M
20000 -11.8 10.8 300 35 18 8.5 4.7 35.1 95.1 2.2 M M
19500 -10.6 12.9 300 35 18 7.4 4.1 34.8 94.6 1.9 M M
19000 -9.5 14.9 300 34 18 7.1 3.9 34.3 93.8 1.5 M M
18500 -8.7 16.3 300 35 18 5.2 2.8 33.6 92.4 0.9 M M
18000 -7.4 18.7 305 37 19 4.4 2.4 32.6 90.6 0.0 M M
17500 -6.9 19.6 305 40 21 3.9 2.2 31.6 88.8 -0.9 1074 5.5
17000 -6.3 20.7 290 45 23 4.0 2.2 30.6 87.0 -1.9 1043 5.3
16500 -5.8 21.6 290 45 23 4.6 2.5 29.6 85.2 -2.8 1013 5.1
16000 -4.9 23.2 290 47 24 7.4 4.1 29.0 84.2 -3.4 972 4.9
15500 -3.8 25.2 285 45 23 7.4 4.1 28.6 83.5 -3.8 924 4.7
15000 -2.8 27.0 280 41 21 6.8 3.7 28.2 82.7 -4.3 879 4.5
14500 -1.8 28.8 290 40 21 6.9 3.8 27.7 81.8 -4.8 834 4.2
14000 -0.8 30.6 285 35 18 6.9 3.8 27.2 81.0 -5.3 790 4.0
13500 0.2 32.4 280 34 18 6.9 3.8 26.8 80.2 -5.7 744 3.8
13000 1.2 34.2 280 33 17 6.9 3.8 26.3 79.3 -6.2 699 3.5
12500 2.2 36.0 295 33 17 6.9 3.8 25.8 78.5 -6.7 653 3.3
12000 3.3 37.9 290 28 14 6.9 3.8 25.4 77.7 -7.1 608 3.1
11500 4.3 39.7 285 26 14 8.6 4.7 24.9 76.9 -7.6 561 2.9
11000 5.8 42.4 290 25 13 9.7 5.3 24.9 76.9 -7.6 503 2.6
10500 7.2 45.0 290 24 12 9.8 5.4 24.9 76.9 -7.7 446 2.3
10250 7.9 46.2 290 23 12 9.5 5.2 24.9 76.9 -7.8 417 2.1
10000 8.6 47.5 290 22 11 8.7 4.8 24.9 76.8 -7.8 390 2.0
9750 9.2 48.6 295 21 11 8.5 4.7 24.8 76.6 -8.0 363 1.8
9500 9.8 49.6 300 21 11 8.6 4.7 24.7 76.5 -8.1 337 1.7
9250 10.4 50.7 300 21 11 8.6 4.7 24.6 76.3 -8.2 311 1.6
9000 11.1 52.0 305 20 10 8.6 4.7 24.6 76.2 -8.3 285 1.4
8750 11.7 53.1 305 19 10 8.6 4.7 24.5 76.0 -8.4 258 1.3
8500 12.3 54.1 305 16 8 8.6 4.7 24.4 75.9 -8.5 232 1.2
8250 13.0 55.4 295 13 7 8.6 4.7 24.3 75.7 -8.6 206 1.0
8000 13.6 56.5 300 14 7 8.6 4.7 24.2 75.5 -8.8 180 0.9
7750 14.2 57.6 300 13 7 8.6 4.7 24.1 75.4 -8.9 153 0.8
7500 14.9 58.8 310 11 6 8.6 4.7 24.0 75.2 -9.0 127 0.6
7250 15.5 59.9 310 9 5 8.6 4.7 23.9 75.0 -9.2 101 0.5
7000 16.1 61.0 310 7 4 8.7 4.8 23.8 74.9 -9.3 75 0.4
6750 16.7 62.1 300 5 3 8.3 4.6 23.7 74.7 -9.4 48 0.2
6500 17.4 63.3 200 2 1 9.6 5.3 23.6 74.5 -9.5 22 0.1
6250 18.0 64.4 160 6 3 7.5 4.1 23.6 74.5 -9.6 M M
6000 18.2 64.8 160 9 5 -1.3 -0.7 23.1 73.6 -10.2 M M
5750 17.9 64.2 150 8 4 -2.8 -1.5 22.1 71.8 -11.2 M M
5500 17.8 64.0 135 7 4 -1.0 -0.6 21.3 70.3 -12.1 M M
5250 17.5 63.5 110 7 3 -6.2 -3.4 20.3 68.5 -13.2 M M
5000 16.9 62.4 090 7 3 -10.5 -5.8 18.9 66.0 -14.6 M M
* * * * * * Numerical weather prediction model forecast data valid * * * * * *
06/04/2024 at 0900 MDT | 06/04/2024 at 1200 MDT
|
CAPE... +0.1 LI... +3.2 | CAPE... +0.3 LI... +3.0
CINH... -1.5 K Index... +16.3 | CINH... -1.6 K Index... +11.5
|
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 -60.4 -76.7 335 43 22 1.6 0.9 | -61.7 -79.1 340 45 23 1.3 0.7
45000 -58.1 -72.6 335 64 33 1.2 0.7 | -59.2 -74.6 340 63 32 2.5 1.3
40000 -55.4 -67.7 335 71 37 8.9 4.9 | -54.8 -66.6 340 61 31 8.3 4.5
38000 -50.4 -58.7 335 67 35 8.3 4.6 | -50.0 -58.0 335 56 29 8.0 4.4
36000 -45.4 -49.7 335 63 32 8.3 4.6 | -45.2 -49.4 335 52 27 8.0 4.4
34000 -40.6 -41.1 330 61 31 7.9 4.4 | -40.2 -40.4 330 48 25 8.3 4.5
32000 -35.8 -32.4 325 59 31 8.0 4.4 | -35.2 -31.4 325 46 24 8.3 4.6
30000 -31.3 -24.3 320 57 29 7.4 4.1 | -30.4 -22.7 325 46 23 7.9 4.3
29000 -29.1 -20.4 320 55 28 7.4 4.1 | -28.1 -18.6 320 46 24 7.9 4.4
28000 -26.9 -16.4 315 53 27 7.5 4.1 | -25.7 -14.3 320 47 24 8.1 4.4
27000 -24.8 -12.6 315 51 26 6.8 3.7 | -23.1 -9.6 315 45 23 6.7 3.7
26000 -22.8 -9.0 320 48 25 6.8 3.7 | -21.1 -6.0 315 44 22 6.7 3.7
25000 -20.3 -4.5 320 45 23 6.8 3.7 | -19.2 -2.6 315 42 22 6.8 3.7
24000 -18.3 -0.9 320 43 22 6.7 3.7 | -17.3 0.9 315 39 20 6.1 3.4
23000 -16.3 2.7 315 41 21 6.7 3.7 | -15.5 4.1 315 36 19 6.1 3.4
22000 -14.3 6.3 315 39 20 6.7 3.7 | -13.6 7.5 310 33 17 6.1 3.3
21000 -12.3 9.9 310 38 20 6.6 3.6 | -11.7 10.9 310 32 17 6.7 3.7
20000 -10.3 13.5 310 38 20 6.6 3.6 | -9.7 14.5 310 32 16 6.7 3.7
19500 -9.3 15.3 310 38 20 6.6 3.6 | -8.7 16.3 310 31 16 6.7 3.7
19000 -8.3 17.1 305 38 20 6.4 3.5 | -7.7 18.1 310 31 16 6.6 3.6
18500 -7.4 18.7 305 38 20 6.2 3.4 | -6.7 19.9 310 32 17 6.5 3.6
18000 -6.5 20.3 305 38 20 6.2 3.4 | -5.8 21.6 310 33 17 6.5 3.6
17500 -5.6 21.9 305 39 20 5.6 3.1 | -4.8 23.4 310 34 17 6.5 3.6
17000 -4.8 23.4 305 38 20 5.7 3.1 | -3.8 25.2 310 34 18 6.5 3.6
16500 -4.0 24.8 305 38 20 5.2 2.8 | -2.9 26.8 310 35 18 6.4 3.5
16000 -3.3 26.1 305 37 19 4.9 2.7 | -1.9 28.6 310 35 18 6.3 3.5
15500 -2.6 27.3 305 36 18 4.8 2.7 | -1.0 30.2 310 35 18 6.1 3.3
15000 -2.0 28.4 305 34 17 4.5 2.5 | -0.2 31.6 310 34 17 5.2 2.9
14500 -1.4 29.5 305 32 16 4.6 2.5 | 0.6 33.1 310 33 17 5.5 3.0
14000 -0.7 30.7 310 29 15 4.6 2.5 | 1.1 34.0 315 30 15 2.1 1.1
13500 -0.1 31.8 310 26 13 4.6 2.5 | 1.4 34.5 315 27 14 2.4 1.3
13000 0.6 33.1 310 23 12 5.1 2.8 | 1.8 35.2 315 23 12 3.8 2.1
12500 1.3 34.3 310 20 10 5.2 2.8 | 2.3 36.1 315 19 10 3.8 2.1
12000 2.1 35.8 310 18 9 6.1 3.3 | 2.9 37.2 310 15 8 6.8 3.7
11500 3.0 37.4 305 16 8 6.4 3.5 | 4.0 39.2 305 14 7 7.4 4.1
11000 3.9 39.0 305 14 7 7.1 3.9 | 5.0 41.0 305 12 6 6.8 3.7
10500 5.0 41.0 305 13 7 6.8 3.7 | 6.0 42.8 300 12 6 5.5 3.0
10250 5.5 41.9 305 13 7 9.6 5.2 | 6.5 43.7 300 12 6 11.4 6.2
10000 6.3 43.3 305 12 6 10.5 5.8 | 7.6 45.7 300 12 6 12.9 7.1
9750 7.0 44.6 305 12 6 8.5 4.7 | 8.3 46.9 300 12 6 8.0 4.4
9500 7.6 45.7 305 12 6 9.0 5.0 | 8.9 48.0 300 12 6 9.8 5.4
9250 9.0 48.2 310 12 6 8.9 4.9 | 10.1 50.2 295 11 6 8.6 4.7
9000 9.6 49.3 310 11 6 8.5 4.7 | 10.9 51.6 295 11 6 11.3 6.2
8750 10.2 50.4 315 11 6 8.9 4.9 | 11.7 53.1 295 11 6 11.1 6.1
8500 10.9 51.6 315 11 6 7.8 4.3 | 12.5 54.5 295 11 6 9.2 5.1
8250 11.4 52.5 315 10 5 7.5 4.1 | 13.1 55.6 295 11 6 8.6 4.7
8000 12.0 53.6 315 10 5 8.8 4.9 | 13.8 56.8 295 11 5 10.9 6.0
7750 12.7 54.9 320 9 5 9.5 5.2 | 14.7 58.5 295 10 5 11.4 6.3
7500 13.4 56.1 320 8 4 7.5 4.1 | 15.5 59.9 295 10 5 8.8 4.8
7250 13.8 56.8 320 7 4 6.2 3.4 | 16.0 60.8 295 10 5 7.3 4.0
7000 14.4 57.9 325 7 3 9.1 5.0 | 16.7 62.1 295 10 5 11.4 6.3
6750 15.1 59.2 325 6 3 10.6 5.8 | 17.7 63.9 295 10 5 12.6 6.9
6500 15.9 60.6 325 6 3 10.2 5.6 | 18.5 65.3 295 10 5 10.5 5.7
6250 16.7 62.1 325 5 3 10.9 6.0 | 19.3 66.7 295 9 5 10.6 5.8
6000 17.4 63.3 325 5 3 8.3 4.6 | 20.0 68.0 295 9 5 8.4 4.6
5750 18.0 64.4 325 5 3 10.4 5.7 | 20.7 69.3 295 9 4 15.2 8.3
5500 20.1 68.2 325 4 2 58.6 32.1 | 23.9 75.0 295 8 4 87.6 48.1
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
06/04/2024 at 1500 MDT | 06/04/2024 at 1800 MDT
|
CAPE... +0.5 LI... +3.0 | CAPE... 0.0 LI... +3.2
CINH... -1.0 K Index... +17.5 | CINH... -0.1 K Index... +19.6
|
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 -62.3 -80.1 350 41 21 0.9 0.5 | -62.8 -81.0 355 35 18 1.1 0.6
45000 -59.9 -75.8 345 53 27 3.6 2.0 | -59.9 -75.8 350 45 23 4.0 2.2
40000 -54.1 -65.4 340 47 24 8.0 4.4 | -53.5 -64.3 335 43 22 7.7 4.2
38000 -49.4 -56.9 335 44 23 7.8 4.3 | -48.4 -55.1 325 38 19 7.6 4.1
36000 -44.1 -47.4 330 41 21 7.7 4.2 | -43.8 -46.8 320 34 17 7.5 4.1
34000 -39.2 -38.6 325 39 20 8.3 4.6 | -38.9 -38.0 320 34 17 8.3 4.6
32000 -34.2 -29.6 320 38 20 8.2 4.5 | -33.9 -29.0 320 35 18 8.2 4.5
30000 -29.4 -20.9 320 39 20 7.9 4.3 | -29.2 -20.6 320 36 18 7.8 4.3
29000 -27.1 -16.8 320 40 21 7.9 4.3 | -26.9 -16.4 320 37 19 7.8 4.3
28000 -24.8 -12.6 320 41 21 7.7 4.2 | -24.6 -12.3 320 37 19 7.6 4.2
27000 -22.6 -8.7 320 41 21 7.1 3.9 | -22.4 -8.3 325 37 19 7.3 4.0
26000 -20.5 -4.9 320 40 21 7.1 3.9 | -20.2 -4.4 325 38 19 7.3 4.0
25000 -18.4 -1.1 320 39 20 7.1 3.9 | -18.0 -0.4 325 38 20 7.4 4.1
24000 -16.5 2.3 320 37 19 6.0 3.3 | -15.6 3.9 325 36 19 6.0 3.3
23000 -14.8 5.4 320 35 18 6.0 3.3 | -13.8 7.2 325 34 17 6.1 3.3
22000 -12.6 9.3 315 31 16 6.0 3.3 | -12.0 10.4 330 32 16 6.1 3.3
21000 -10.7 12.7 315 30 15 6.4 3.5 | -10.3 13.5 325 30 15 6.1 3.4
20000 -8.8 16.2 310 28 15 6.4 3.5 | -8.5 16.7 320 28 14 6.1 3.4
19500 -7.9 17.8 310 28 14 6.5 3.6 | -7.6 18.3 320 27 14 6.2 3.4
19000 -6.9 19.6 310 27 14 6.0 3.3 | -6.7 19.9 315 26 13 5.8 3.2
18500 -6.0 21.2 310 27 14 5.9 3.3 | -5.8 21.6 315 25 13 5.8 3.2
18000 -5.2 22.6 310 27 14 5.8 3.2 | -5.0 23.0 310 25 13 5.3 2.9
17500 -4.3 24.3 310 27 14 5.4 3.0 | -4.4 24.1 310 23 12 3.8 2.1
17000 -3.6 25.5 310 26 14 5.5 3.0 | -3.9 25.0 310 22 11 3.7 2.0
16500 -2.8 27.0 315 26 13 4.8 2.7 | -3.3 26.1 305 20 10 5.6 3.1
16000 -2.1 28.2 315 25 13 4.8 2.6 | -2.5 27.5 305 19 10 5.7 3.1
15500 -1.4 29.5 315 24 12 5.1 2.8 | -1.6 29.1 305 17 9 6.6 3.6
15000 -0.7 30.7 315 22 11 5.4 3.0 | -0.5 31.1 310 16 8 7.4 4.1
14500 0.1 32.2 315 21 11 5.6 3.1 | 0.6 33.1 310 16 8 7.6 4.2
14000 1.1 34.0 315 19 10 7.2 4.0 | 1.7 35.1 315 15 7 8.1 4.5
13500 2.1 35.8 315 18 9 7.1 3.9 | 3.0 37.4 315 13 7 8.1 4.4
13000 3.1 37.6 315 16 8 7.5 4.1 | 4.2 39.6 315 13 7 8.5 4.7
12500 4.2 39.6 315 15 8 7.4 4.1 | 5.4 41.7 315 12 6 8.4 4.6
12000 5.3 41.5 310 13 7 8.2 4.5 | 6.7 44.1 315 12 6 9.0 4.9
11500 6.5 43.7 305 13 7 8.3 4.6 | 8.0 46.4 315 12 6 9.1 5.0
11000 7.7 45.9 305 12 6 7.3 4.0 | 9.3 48.7 310 12 6 7.6 4.2
10500 8.7 47.7 300 12 6 7.3 4.0 | 10.4 50.7 310 12 6 8.4 4.6
10250 9.4 48.9 300 12 6 12.1 6.6 | 11.2 52.2 310 11 6 12.6 6.9
10000 10.4 50.7 295 11 6 12.3 6.7 | 12.1 53.8 310 11 6 11.4 6.2
9750 11.1 52.0 295 11 6 8.8 4.8 | 12.8 55.0 310 11 6 8.4 4.6
9500 11.8 53.2 295 11 6 10.2 5.6 | 13.5 56.3 310 11 6 9.6 5.3
9250 12.5 54.5 295 11 6 8.1 4.5 | 14.2 57.6 310 11 6 7.5 4.1
9000 13.1 55.6 295 12 6 8.9 4.9 | 14.7 58.5 310 11 6 8.2 4.5
8750 13.9 57.0 295 11 6 11.0 6.0 | 16.2 61.2 310 11 6 10.2 5.6
8500 14.7 58.5 290 11 6 10.9 6.0 | 16.9 62.4 310 11 5 9.0 4.9
8250 16.1 61.0 290 11 6 8.9 4.9 | 17.5 63.5 310 11 6 9.0 4.9
8000 16.8 62.2 290 11 6 11.0 6.0 | 18.3 64.9 310 11 5 10.5 5.8
7750 17.7 63.9 290 11 5 11.0 6.0 | 19.0 66.2 310 10 5 10.4 5.7
7500 18.4 65.1 290 10 5 9.1 5.0 | 19.8 67.6 310 10 5 8.7 4.8
7250 19.0 66.2 290 11 5 8.2 4.5 | 20.4 68.7 310 10 5 8.2 4.5
7000 19.8 67.6 285 11 5 11.3 6.2 | 21.1 70.0 310 10 5 10.8 5.9
6750 20.6 69.1 285 10 5 12.0 6.6 | 21.9 71.4 310 10 5 11.4 6.3
6500 21.5 70.7 285 10 5 10.5 5.8 | 22.7 72.9 310 10 5 10.4 5.7
6250 22.3 72.1 285 10 5 10.9 6.0 | 23.5 74.3 310 10 5 10.7 5.8
6000 23.0 73.4 285 10 5 8.0 4.4 | 24.3 75.7 310 10 5 8.0 4.4
5750 23.7 74.7 285 9 4 14.2 7.8 | 24.8 76.6 310 9 5 10.2 5.6
5500 26.9 80.4 285 9 4 91.6 50.3 | 27.0 80.6 315 8 4 60.5 33.2
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
________________________________________________________________________________
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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