Soaring Guidance
Issued by NWS Grand Junction, CO
Issued by NWS Grand Junction, CO
162
UXUS97 KGJT 071307
SRGGJT
Soaring Forecast
National Weather Service Grand Junction, Colorado
707 AM MDT Tuesday, May 7, 2024
This forecast is for Tuesday, May 7, 2024:
If the trigger temperature of 52.5 F/11.4 C is reached...then
Thermal Soaring Index....................... Good
Maximum rate of lift........................ 940 ft/min (4.8 m/s)
Maximum height of thermals.................. 15855 ft MSL (11016 ft AGL)
Forecast maximum temperature................... 63.0 F/17.7 C
Time of trigger temperature.................... 0945 MDT
Time of overdevelopment........................ None
Middle/high clouds during soaring window....... None
Surface winds during soaring window............ Between 20 mph and 30 mph
Height of the -3 thermal index................. 12323 ft MSL (7484 ft AGL)
Thermal soaring outlook for Wednesday 05/08.... Excellent
Wave Soaring Index............................. Not available
Remarks...
Sunrise/Sunset.................... 06:08:01 / 20:13:17 MDT
Total possible sunshine........... 14 hr 5 min 16 sec (845 min 16 sec)
Altitude of sun at 13:10:39 MDT... 67.87 degrees
Upper air data from rawinsonde observation taken on 05/07/2024 at 0600 MDT
Freezing level.................. 8627 ft MSL (3788 ft AGL)
Convective condensation level... 13605 ft MSL (8766 ft AGL)
Lifted condensation level....... 14619 ft MSL (9779 ft AGL)
Lifted index.................... +1.3
K index......................... +17.1
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 -53.6 -64.5 250 39 20 4.2 2.3 112.0 233.5 54.0 M M
45000 -48.5 -55.3 250 38 19 2.4 1.3 94.6 202.3 47.3 M M
40000 -49.9 -57.8 280 81 42 1.5 0.8 69.3 156.8 34.0 M M
38000 -50.5 -58.9 275 91 47 -1.2 -0.7 59.5 139.1 28.3 M M
36000 -50.6 -59.1 280 91 47 2.2 1.2 50.8 123.4 23.1 M M
34000 -49.7 -57.5 270 99 51 -0.4 -0.2 43.6 110.5 18.6 M M
32000 -47.9 -54.2 275 105 54 5.4 3.0 36.9 98.4 14.3 M M
30000 -44.6 -48.3 275 120 62 7.7 4.2 33.5 92.3 12.1 M M
29000 -42.1 -43.8 270 120 62 8.0 4.4 32.9 91.2 11.8 M M
28000 -40.2 -40.4 275 111 57 3.8 2.1 31.5 88.7 10.9 M M
27000 -39.0 -38.2 280 103 53 3.6 2.0 29.3 84.7 9.3 M M
26000 -37.1 -34.8 280 105 54 7.5 4.1 28.1 82.5 8.5 M M
25000 -34.9 -30.8 280 101 52 7.5 4.1 27.2 81.0 7.9 M M
24000 -32.8 -27.0 280 96 50 4.1 2.3 26.1 79.1 7.1 M M
23000 -31.0 -23.8 275 92 47 8.4 4.6 24.8 76.6 6.1 M M
22000 -29.2 -20.6 275 84 43 3.0 1.6 23.3 74.0 5.0 M M
21000 -28.3 -18.9 285 70 36 3.6 2.0 21.0 69.8 3.1 M M
20000 -26.5 -15.7 280 63 32 6.7 3.7 19.7 67.5 2.0 M M
19500 -25.4 -13.7 275 61 31 7.8 4.3 19.2 66.6 1.6 M M
19000 -24.1 -11.4 280 58 30 9.0 4.9 19.1 66.3 1.5 M M
18500 -23.0 -9.4 280 56 29 5.5 3.0 18.7 65.7 1.2 M M
18000 -21.4 -6.5 275 51 26 15.5 8.5 18.9 66.0 1.3 M M
17500 -19.7 -3.5 275 49 25 9.9 5.5 19.2 66.6 1.6 M M
17000 -17.9 -0.2 280 49 25 5.8 3.2 18.8 65.9 1.2 M M
16500 -17.0 1.4 275 48 25 6.1 3.3 18.2 64.7 0.6 M M
16000 -16.1 3.0 270 48 25 6.1 3.3 17.6 63.6 0.1 M M
15500 -15.2 4.6 270 44 23 6.1 3.3 16.9 62.5 -0.5 902 4.6
15000 -14.3 6.3 275 41 21 6.0 3.3 16.3 61.4 -1.1 860 4.4
14500 -13.3 8.1 270 41 21 7.6 4.2 15.8 60.4 -1.6 816 4.1
14000 -12.2 10.0 265 42 22 7.7 4.2 15.5 59.9 -1.9 767 3.9
13500 -11.0 12.2 265 43 22 7.7 4.2 15.1 59.2 -2.2 718 3.6
13000 -9.9 14.2 260 44 23 7.7 4.2 14.8 58.7 -2.6 669 3.4
12500 -8.7 16.3 255 39 20 7.7 4.3 14.5 58.0 -2.9 620 3.1
12000 -7.6 18.3 245 34 18 7.8 4.3 14.1 57.4 -3.2 571 2.9
11500 -6.6 20.1 255 28 14 6.0 3.3 13.7 56.6 -3.7 526 2.7
11000 -5.6 21.9 265 22 11 7.3 4.0 13.2 55.7 -4.2 481 2.4
10500 -4.5 23.9 265 18 9 7.2 4.0 12.8 55.0 -4.6 434 2.2
10250 -4.0 24.8 275 18 9 7.2 3.9 12.6 54.6 -4.8 410 2.1
10000 -3.4 25.9 275 18 9 7.3 4.0 12.4 54.2 -5.0 387 2.0
9750 -2.9 26.8 265 17 9 8.1 4.4 12.2 54.0 -5.2 362 1.8
9500 -2.2 28.0 260 18 9 8.4 4.6 12.1 53.8 -5.3 336 1.7
9250 -1.6 29.1 255 19 10 8.3 4.6 12.0 53.6 -5.4 310 1.6
9000 -1.0 30.2 250 20 10 8.3 4.6 11.9 53.4 -5.5 284 1.4
8750 -0.4 31.3 250 20 10 8.3 4.6 11.8 53.2 -5.6 258 1.3
8500 0.3 32.5 255 19 10 8.3 4.6 11.7 53.1 -5.7 232 1.2
8250 0.9 33.6 255 16 8 8.3 4.6 11.6 52.9 -5.9 206 1.0
8000 1.5 34.7 250 12 6 8.3 4.6 11.5 52.7 -6.0 180 0.9
7750 2.1 35.8 245 11 5 8.3 4.6 11.4 52.5 -6.1 154 0.8
7500 2.7 36.9 245 8 4 8.3 4.6 11.3 52.3 -6.2 128 0.7
7250 3.4 38.1 250 6 3 8.3 4.6 11.2 52.1 -6.4 102 0.5
7000 4.0 39.2 275 3 2 8.3 4.6 11.0 51.9 -6.5 76 0.4
6750 4.6 40.3 275 2 1 8.4 4.6 10.9 51.7 -6.6 50 0.3
6500 5.2 41.4 190 1 0 8.3 4.5 10.8 51.5 -6.7 24 0.1
6250 5.8 42.4 155 2 1 8.6 4.7 10.7 51.3 -6.9 M M
6000 6.5 43.7 145 3 2 7.4 4.1 10.6 51.1 -7.0 M M
5750 6.9 44.4 120 2 1 5.4 3.0 10.3 50.6 -7.3 M M
5500 7.3 45.1 035 2 1 6.6 3.6 10.0 50.0 -7.7 M M
5250 7.7 45.9 345 2 1 2.5 1.4 9.7 49.5 -8.0 M M
5000 7.4 45.3 215 2 1 -8.8 -4.8 8.7 47.7 -9.1 M M
* * * * * * Numerical weather prediction model forecast data valid * * * * * *
05/07/2024 at 0900 MDT | 05/07/2024 at 1200 MDT
|
CAPE... +22.9 LI... +0.3 | CAPE... +132.3 LI... -1.4
CINH... -15.8 K Index... +16.8 | CINH... -5.4 K Index... +17.5
|
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 -53.2 -63.8 250 34 17 2.6 1.4 | -52.7 -62.9 250 32 16 2.5 1.4
45000 -49.3 -56.7 270 48 25 1.4 0.8 | -49.0 -56.2 265 44 22 1.4 0.8
40000 -49.2 -56.6 275 72 37 0.0 0.0 | -48.9 -56.0 270 72 37 0.0 0.0
38000 -49.0 -56.2 275 81 42 0.9 0.5 | -48.7 -55.7 270 84 43 1.0 0.6
36000 -48.4 -55.1 275 92 47 0.9 0.5 | -48.0 -54.4 270 98 50 1.0 0.6
34000 -47.9 -54.2 275 101 52 2.5 1.4 | -47.4 -53.3 275 110 57 2.8 1.5
32000 -45.8 -50.4 275 108 55 3.4 1.9 | -45.0 -49.0 270 111 57 3.9 2.1
30000 -43.7 -46.7 270 114 59 4.9 2.7 | -42.7 -44.9 270 112 57 4.5 2.5
29000 -41.9 -43.4 270 112 57 6.1 3.3 | -41.2 -42.2 270 110 56 5.1 2.8
28000 -40.1 -40.2 270 109 56 6.1 3.3 | -39.7 -39.5 270 107 55 5.1 2.8
27000 -38.3 -36.9 270 107 55 6.1 3.4 | -38.2 -36.8 270 105 54 5.1 2.8
26000 -36.4 -33.5 270 104 54 6.5 3.6 | -36.4 -33.5 270 103 53 6.6 3.6
25000 -34.4 -29.9 270 101 52 6.5 3.6 | -34.5 -30.1 270 102 52 6.6 3.6
24000 -32.5 -26.5 270 97 50 6.5 3.6 | -32.5 -26.5 270 100 52 6.6 3.6
23000 -30.7 -23.3 270 92 48 4.7 2.6 | -30.6 -23.1 270 97 50 5.7 3.2
22000 -28.9 -20.0 270 83 43 4.8 2.6 | -28.4 -19.1 270 90 46 5.8 3.2
21000 -27.5 -17.5 270 76 39 4.9 2.7 | -26.7 -16.1 270 84 43 5.9 3.2
20000 -25.9 -14.6 270 70 36 5.5 3.0 | -25.6 -14.1 270 74 38 3.2 1.7
19500 -25.1 -13.2 270 67 35 5.5 3.0 | -25.1 -13.2 270 69 35 3.2 1.8
19000 -24.3 -11.7 270 64 33 5.5 3.0 | -24.7 -12.5 270 63 32 3.2 1.8
18500 -23.5 -10.3 270 62 32 5.4 3.0 | -24.2 -11.6 270 58 30 2.9 1.6
18000 -22.5 -8.5 270 59 30 7.7 4.2 | -23.5 -10.3 265 53 28 7.5 4.1
17500 -21.4 -6.5 265 57 29 7.5 4.1 | -22.4 -8.3 265 51 26 7.2 3.9
17000 -20.3 -4.5 265 55 28 7.9 4.3 | -21.4 -6.5 265 49 25 8.1 4.4
16500 -19.1 -2.4 265 53 27 8.1 4.4 | -20.1 -4.2 265 47 24 8.6 4.7
16000 -17.9 -0.2 265 50 26 8.0 4.4 | -18.8 -1.8 265 46 24 8.6 4.7
15500 -16.8 1.8 265 49 25 7.7 4.2 | -17.5 0.5 265 45 23 8.5 4.7
15000 -15.7 3.7 265 48 24 7.7 4.2 | -16.3 2.7 265 44 23 8.6 4.7
14500 -14.5 5.9 265 46 24 7.6 4.2 | -15.1 4.8 265 43 22 8.4 4.6
14000 -13.4 7.9 265 45 23 7.6 4.1 | -13.8 7.2 265 42 22 8.4 4.6
13500 -12.2 10.0 265 43 22 8.6 4.7 | -12.6 9.3 265 41 21 8.7 4.8
13000 -11.0 12.2 265 41 21 8.6 4.7 | -11.3 11.7 265 39 20 8.7 4.8
12500 -9.7 14.5 265 39 20 7.8 4.3 | -10.0 14.0 265 38 20 8.7 4.8
12000 -8.6 16.5 270 36 18 7.7 4.2 | -8.7 16.3 265 37 19 8.7 4.8
11500 -7.4 18.7 270 33 17 8.3 4.6 | -7.4 18.7 265 35 18 8.7 4.8
11000 -6.2 20.8 270 30 16 8.5 4.7 | -6.1 21.0 265 34 18 8.9 4.9
10500 -5.0 23.0 265 28 14 7.0 3.8 | -4.9 23.2 265 33 17 7.1 3.9
10250 -4.5 23.9 270 27 14 6.8 3.7 | -4.4 24.1 265 32 17 7.1 3.9
10000 -3.9 25.0 270 27 14 10.6 5.8 | -3.8 25.2 265 32 16 11.0 6.0
9750 -3.0 26.6 265 26 13 10.6 5.8 | -2.9 26.8 265 31 16 11.0 6.0
9500 -2.4 27.7 265 25 13 7.7 4.2 | -2.2 28.0 265 30 16 8.1 4.5
9250 -1.8 28.8 265 24 12 7.8 4.3 | -1.6 29.1 265 29 15 7.7 4.2
9000 -1.2 29.8 265 23 12 9.4 5.2 | -1.0 30.2 265 28 14 10.1 5.5
8750 -0.4 31.3 265 22 11 9.6 5.3 | -0.2 31.6 265 28 15 10.9 6.0
8500 0.2 32.4 265 21 11 7.8 4.3 | 0.5 32.9 265 27 14 8.9 4.9
8250 0.8 33.4 265 20 10 8.4 4.6 | 1.9 35.4 270 26 13 8.1 4.4
8000 1.4 34.5 260 19 10 7.8 4.3 | 2.5 36.5 270 24 12 8.8 4.8
7750 2.6 36.7 260 18 9 8.2 4.5 | 3.2 37.8 270 23 12 10.5 5.8
7500 3.2 37.8 260 16 8 8.7 4.8 | 4.0 39.2 270 23 12 11.3 6.2
7250 3.8 38.8 260 15 8 6.3 3.5 | 4.8 40.6 270 22 12 6.5 3.5
7000 4.2 39.6 260 14 7 6.6 3.6 | 5.1 41.2 275 21 11 7.3 4.0
6750 4.9 40.8 260 13 7 9.4 5.2 | 6.0 42.8 275 20 10 13.1 7.2
6500 5.5 41.9 255 11 6 8.1 4.4 | 6.9 44.4 270 20 10 10.9 6.0
6250 6.0 42.8 255 9 4 6.9 3.8 | 7.6 45.7 275 19 10 8.8 4.8
6000 6.5 43.7 260 6 3 6.3 3.5 | 8.2 46.8 280 17 9 7.9 4.4
5750 7.0 44.6 255 6 3 8.9 4.9 | 9.0 48.2 275 17 9 16.9 9.2
5500 8.1 46.6 260 3 2 22.0 12.1 | 11.1 52.0 280 13 7 44.7 24.5
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
05/07/2024 at 1500 MDT | 05/07/2024 at 1800 MDT
|
CAPE... +63.1 LI... -0.2 | CAPE... +11.2 LI... +1.6
CINH... -1.4 K Index... +10.5 | CINH... -0.3 K Index... +9.4
|
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 -52.2 -62.0 255 31 16 1.8 1.0 | -51.4 -60.5 260 24 12 1.1 0.6
45000 -49.5 -57.1 265 42 22 1.3 0.7 | -49.8 -57.6 275 34 18 1.3 0.7
40000 -48.3 -54.9 270 67 34 0.8 0.4 | -47.5 -53.5 275 64 33 1.5 0.8
38000 -47.8 -54.0 270 78 40 0.8 0.4 | -46.8 -52.2 270 75 38 0.3 0.1
36000 -47.3 -53.1 270 93 48 0.8 0.4 | -46.7 -52.1 270 86 44 0.2 0.1
34000 -46.9 -52.4 270 105 54 2.6 1.4 | -46.5 -51.7 265 96 49 1.4 0.8
32000 -44.6 -48.3 270 106 55 3.8 2.1 | -45.0 -49.0 270 95 49 2.6 1.4
30000 -42.4 -44.3 270 106 55 3.9 2.1 | -43.4 -46.1 270 94 48 3.0 1.7
29000 -41.2 -42.2 270 103 53 4.0 2.2 | -42.3 -44.1 270 92 47 3.8 2.1
28000 -40.0 -40.0 270 99 51 4.0 2.2 | -41.2 -42.2 270 90 46 3.8 2.1
27000 -38.8 -37.8 270 95 49 4.1 2.2 | -40.0 -40.0 270 88 45 3.9 2.1
26000 -37.2 -35.0 270 92 47 6.7 3.7 | -38.4 -37.1 270 86 44 7.5 4.1
25000 -35.1 -31.2 270 90 46 6.8 3.7 | -36.2 -33.2 270 86 44 7.5 4.1
24000 -33.1 -27.6 270 88 45 6.8 3.7 | -33.9 -29.0 265 85 44 7.5 4.1
23000 -31.1 -24.0 265 85 44 6.4 3.5 | -31.7 -25.1 265 83 43 7.3 4.0
22000 -28.7 -19.7 265 79 41 6.4 3.5 | -29.0 -20.2 265 80 41 7.3 4.0
21000 -26.8 -16.2 265 75 39 6.4 3.5 | -26.8 -16.2 265 78 40 7.4 4.0
20000 -25.7 -14.3 265 66 34 3.2 1.8 | -25.4 -13.7 265 71 36 4.0 2.2
19500 -25.2 -13.4 265 61 32 3.3 1.8 | -24.8 -12.6 265 67 34 4.0 2.2
19000 -24.7 -12.5 265 57 29 3.3 1.8 | -24.2 -11.6 265 63 32 4.0 2.2
18500 -24.2 -11.6 270 52 27 2.9 1.6 | -23.6 -10.5 265 59 30 3.9 2.1
18000 -23.5 -10.3 270 48 25 7.5 4.1 | -22.9 -9.2 270 55 28 5.2 2.9
17500 -22.4 -8.3 270 45 23 7.1 3.9 | -22.2 -8.0 265 51 26 5.1 2.8
17000 -21.4 -6.5 270 43 22 7.8 4.3 | -21.4 -6.5 265 47 24 6.8 3.7
16500 -20.2 -4.4 270 42 21 8.3 4.5 | -20.2 -4.4 265 45 23 7.8 4.3
16000 -18.9 -2.0 270 41 21 8.4 4.6 | -19.1 -2.4 265 42 22 8.0 4.4
15500 -17.7 0.1 270 40 21 8.6 4.7 | -17.9 -0.2 265 41 21 8.3 4.5
15000 -16.4 2.5 270 40 20 8.6 4.7 | -16.6 2.1 265 40 20 8.3 4.5
14500 -15.1 4.8 270 39 20 8.8 4.8 | -15.4 4.3 265 38 20 8.2 4.5
14000 -13.8 7.2 270 39 20 8.8 4.8 | -14.2 6.4 265 37 19 8.2 4.5
13500 -12.5 9.5 270 38 20 8.8 4.8 | -12.9 8.8 270 35 18 8.7 4.8
13000 -11.2 11.8 270 37 19 8.7 4.8 | -11.6 11.1 270 34 18 8.7 4.8
12500 -9.9 14.2 270 36 19 9.3 5.1 | -10.3 13.5 275 33 17 8.8 4.8
12000 -8.5 16.7 270 35 18 9.3 5.1 | -9.0 15.8 275 32 16 8.8 4.8
11500 -7.1 19.2 270 35 18 9.7 5.3 | -7.7 18.1 275 31 16 9.4 5.1
11000 -5.7 21.7 270 34 18 9.8 5.4 | -6.3 20.7 280 30 16 9.5 5.2
10500 -4.3 24.3 270 34 17 8.3 4.5 | -4.9 23.2 280 30 15 8.2 4.5
10250 -3.7 25.3 270 34 17 8.6 4.7 | -4.3 24.3 280 30 15 8.3 4.6
10000 -2.9 26.8 270 34 17 11.3 6.2 | -3.6 25.5 280 29 15 11.1 6.1
9750 -2.0 28.4 270 34 17 11.3 6.2 | -2.7 27.1 280 29 15 11.3 6.2
9500 -1.3 29.7 270 34 17 9.5 5.2 | -2.0 28.4 280 29 15 9.5 5.2
9250 -0.6 30.9 270 33 17 9.6 5.2 | -1.3 29.7 280 29 15 9.7 5.3
9000 0.1 32.2 270 33 17 10.1 5.6 | -0.6 30.9 280 29 15 9.8 5.4
8750 0.9 33.6 270 33 17 10.3 5.7 | 0.2 32.4 285 29 15 10.0 5.5
8500 1.7 35.1 270 33 17 9.8 5.4 | 1.7 35.1 285 28 14 9.9 5.4
8250 3.1 37.6 270 32 17 9.8 5.4 | 2.4 36.3 285 28 14 10.0 5.5
8000 3.9 39.0 270 33 17 9.9 5.4 | 3.2 37.8 285 28 15 10.0 5.5
7750 4.6 40.3 270 32 16 9.8 5.4 | 3.9 39.0 285 28 14 9.6 5.3
7500 5.4 41.7 275 31 16 10.3 5.7 | 4.6 40.3 285 27 14 10.1 5.5
7250 6.1 43.0 275 31 16 8.3 4.6 | 5.4 41.7 285 26 13 8.6 4.7
7000 6.7 44.1 275 32 16 9.1 5.0 | 6.0 42.8 285 27 14 9.1 5.0
6750 7.5 45.5 275 30 16 11.8 6.4 | 6.7 44.1 285 26 13 10.9 6.0
6500 8.3 46.9 275 29 15 10.9 6.0 | 7.5 45.5 290 24 13 10.4 5.7
6250 9.2 48.6 275 28 14 12.1 6.6 | 8.3 46.9 290 24 12 11.7 6.4
6000 10.0 50.0 275 29 15 9.0 5.0 | 9.2 48.6 290 25 13 9.1 5.0
5750 10.7 51.3 275 26 13 12.8 7.0 | 9.8 49.6 290 22 11 9.8 5.4
5500 13.5 56.3 275 22 11 81.0 44.4 | 11.8 53.2 290 19 10 57.3 31.4
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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