Soaring Guidance
Issued by NWS Grand Junction, CO
Issued by NWS Grand Junction, CO
850
UXUS97 KGJT 051306
SRGGJT
Soaring Forecast
National Weather Service Grand Junction, Colorado
606 AM MST Wednesday, February 5, 2025
This forecast is for Wednesday, February 5, 2025:
If the trigger temperature of 59.2 F/15.1 C is reached...then
Thermal Soaring Index....................... Good
Maximum rate of lift........................ 750 ft/min (3.8 m/s)
Maximum height of thermals.................. 13930 ft MSL (9091 ft AGL)
Forecast maximum temperature................... 67.0 F/19.9 C
Time of trigger temperature.................... 1045 MST
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................. 10826 ft MSL (5986 ft AGL)
Thermal soaring outlook for Thursday 02/06..... Good
Wave Soaring Index............................. Not available
Remarks...
Sunrise/Sunset.................... 07:16:21 / 17:40:00 MST
Total possible sunshine........... 10 hr 23 min 39 sec (623 min 39 sec)
Altitude of sun at 12:28:11 MST... 34.82 degrees
Upper air data from rawinsonde observation taken on 02/05/2025 at 0500 MST
Freezing level.................. 9944 ft MSL (5105 ft AGL)
Convective condensation level... 15749 ft MSL (10910 ft AGL)
Lifted condensation level....... 15245 ft MSL (10406 ft AGL)
Lifted index.................... +3.1
K index......................... +1.4
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 -60.4 -76.7 255 70 36 7.1 3.9 97.1 206.8 44.6 M M
45000 -54.6 -66.3 265 94 48 1.5 0.8 82.4 180.3 38.7 M M
40000 -48.1 -54.6 270 117 60 6.4 3.5 69.6 157.2 32.9 M M
38000 -44.0 -47.2 270 117 60 3.2 1.7 65.8 150.4 31.3 M M
36000 -40.9 -41.6 270 114 59 6.0 3.3 61.7 143.0 29.3 M M
34000 -38.3 -36.9 280 129 66 -3.2 -1.7 57.0 134.6 26.7 M M
32000 -40.1 -40.2 275 111 57 3.0 1.7 46.4 115.5 19.6 M M
30000 -38.8 -37.8 280 99 51 2.5 1.4 40.3 104.5 15.6 M M
29000 -38.0 -36.4 280 95 49 2.4 1.3 37.3 99.2 13.6 M M
28000 -37.0 -34.6 280 81 42 5.9 3.3 34.8 94.6 11.8 M M
27000 -35.2 -31.4 275 68 35 6.7 3.7 33.3 91.9 10.8 M M
26000 -33.3 -27.9 275 70 36 6.6 3.6 32.1 89.8 9.9 M M
25000 -31.3 -24.3 275 81 42 6.6 3.6 30.9 87.6 9.1 M M
24000 -29.3 -20.7 275 82 42 6.6 3.6 29.7 85.4 8.2 M M
23000 -26.7 -16.1 265 77 39 8.9 4.9 29.2 84.6 7.9 M M
22000 -24.3 -11.7 265 77 40 7.0 3.8 28.6 83.5 7.5 M M
21000 -22.5 -8.5 260 67 35 5.5 3.0 27.3 81.2 6.5 M M
20000 -20.3 -4.5 250 61 31 7.3 4.0 25.6 78.1 5.1 M M
19500 -19.7 -3.5 250 57 29 -3.9 -2.2 24.6 76.2 4.3 M M
19000 -19.6 -3.3 250 57 29 9.0 4.9 23.0 73.4 3.0 M M
18500 -18.2 -0.8 245 55 29 8.8 4.8 22.9 73.2 2.9 M M
18000 -16.9 1.6 250 54 28 8.7 4.8 22.7 72.8 2.8 M M
17500 -15.6 3.9 250 51 27 8.7 4.8 22.5 72.5 2.6 M M
17000 -14.3 6.3 245 49 25 9.0 4.9 22.3 72.2 2.5 M M
16500 -13.2 8.2 245 48 25 6.1 3.3 21.9 71.4 2.1 M M
16000 -12.2 10.0 245 46 24 7.0 3.9 21.4 70.6 1.7 M M
15500 -11.1 12.0 240 45 23 7.1 3.9 21.0 69.7 1.3 M M
15000 -10.1 13.8 240 44 22 7.1 3.9 20.5 69.0 0.9 M M
14500 -9.0 15.8 240 40 21 7.2 3.9 20.1 68.1 0.4 M M
14000 -8.0 17.6 245 37 19 7.3 4.0 19.7 67.4 0.0 M M
13500 -7.0 19.4 245 36 19 8.0 4.4 19.2 66.6 -0.4 707 3.6
13000 -5.7 21.7 250 39 20 7.8 4.3 19.0 66.2 -0.6 654 3.3
12500 -4.7 23.5 250 42 21 6.4 3.5 18.6 65.4 -1.0 608 3.1
12000 -3.8 25.2 245 42 22 6.2 3.4 18.0 64.4 -1.6 567 2.9
11500 -2.9 26.8 240 37 19 6.3 3.4 17.4 63.4 -2.2 525 2.7
11000 -2.0 28.4 235 32 17 6.3 3.5 16.9 62.4 -2.8 483 2.5
10500 -1.1 30.0 235 29 15 6.2 3.4 16.3 61.4 -3.4 442 2.2
10250 -0.6 30.9 240 26 13 5.5 3.0 16.0 60.8 -3.7 421 2.1
10000 -0.2 31.6 245 22 11 7.2 4.0 15.7 60.3 -4.0 401 2.0
9750 0.5 32.9 245 25 13 9.5 5.2 15.6 60.1 -4.1 374 1.9
9500 1.2 34.2 245 22 11 9.5 5.2 15.6 60.1 -4.1 345 1.8
9250 1.9 35.4 240 20 10 9.5 5.2 15.6 60.1 -4.1 316 1.6
9000 2.6 36.7 230 17 9 9.5 5.2 15.6 60.1 -4.1 288 1.5
8750 3.3 37.9 230 18 9 9.5 5.2 15.6 60.1 -4.2 259 1.3
8500 4.0 39.2 230 18 9 9.5 5.2 15.6 60.0 -4.2 230 1.2
8250 4.7 40.5 235 19 10 9.5 5.2 15.6 60.0 -4.2 202 1.0
8000 5.4 41.7 225 16 8 9.5 5.2 15.5 60.0 -4.3 173 0.9
7750 6.1 43.0 225 15 7 9.5 5.2 15.5 59.9 -4.3 144 0.7
7500 6.8 44.2 220 13 7 9.5 5.2 15.5 59.9 -4.3 115 0.6
7250 7.6 45.7 220 11 6 9.5 5.2 15.5 59.9 -4.4 87 0.4
7000 8.3 46.9 230 8 4 9.5 5.2 15.5 59.8 -4.4 58 0.3
6750 9.0 48.2 230 6 3 9.5 5.2 15.4 59.8 -4.4 29 0.1
6500 9.7 49.5 230 4 2 9.5 5.2 15.4 59.7 -4.5 1 0.0
6250 10.4 50.7 225 2 1 9.4 5.2 15.4 59.7 -4.5 M M
6000 11.1 52.0 190 3 1 9.8 5.4 15.3 59.6 -4.6 M M
5750 11.8 53.2 170 4 2 8.3 4.6 15.3 59.5 -4.6 M M
5500 12.4 54.3 155 6 3 8.9 4.9 15.1 59.3 -4.8 M M
5250 12.8 55.0 150 8 4 -3.1 -1.7 14.8 58.7 -5.1 M M
5000 11.4 52.5 145 8 4 -35.3 -19.4 12.7 54.8 -7.3 M M
* * * * * * Numerical weather prediction model forecast data valid * * * * * *
02/05/2025 at 0800 MST | 02/05/2025 at 1100 MST
|
CAPE... 0.0 LI... +5.2 | CAPE... 0.0 LI... +4.3
CINH... 0.0 K Index... +7.5 | CINH... 0.0 K Index... +10.3
|
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 -61.8 -79.2 265 65 33 3.5 1.9 | -61.8 -79.2 260 65 33 2.4 1.3
45000 -56.0 -68.8 270 106 55 4.9 2.7 | -57.9 -72.2 265 107 55 5.6 3.1
40000 -48.7 -55.7 270 124 64 4.9 2.7 | -49.2 -56.6 270 125 64 5.4 3.0
38000 -46.1 -51.0 270 127 65 4.1 2.2 | -46.4 -51.5 270 129 67 4.4 2.4
36000 -43.6 -46.5 275 128 66 4.1 2.2 | -43.7 -46.7 275 133 69 4.4 2.4
34000 -41.7 -43.1 275 128 66 0.3 0.2 | -41.6 -42.9 275 134 69 0.8 0.5
32000 -41.5 -42.7 275 121 62 0.3 0.2 | -41.2 -42.2 270 126 65 0.7 0.4
30000 -40.7 -41.3 275 114 59 6.1 3.3 | -40.2 -40.4 270 117 60 5.9 3.2
29000 -39.0 -38.2 275 111 57 5.7 3.1 | -38.5 -37.3 270 112 58 5.7 3.1
28000 -37.3 -35.1 275 108 56 5.7 3.1 | -36.8 -34.2 265 107 55 5.7 3.1
27000 -35.1 -31.2 275 105 54 7.0 3.8 | -35.1 -31.2 265 103 53 5.9 3.2
26000 -32.9 -27.2 275 100 51 7.5 4.1 | -32.5 -26.5 265 98 51 7.1 3.9
25000 -30.6 -23.1 275 95 49 7.6 4.1 | -30.3 -22.5 265 95 49 7.1 3.9
24000 -28.3 -18.9 275 90 46 7.3 4.0 | -28.2 -18.8 270 92 47 7.0 3.8
23000 -26.2 -15.2 275 83 43 6.9 3.8 | -26.1 -15.0 270 86 44 6.8 3.7
22000 -24.2 -11.6 270 76 39 6.9 3.8 | -24.1 -11.4 270 80 41 6.8 3.7
21000 -22.1 -7.8 270 69 36 7.2 4.0 | -22.0 -7.6 270 73 38 6.7 3.7
20000 -19.9 -3.8 265 65 34 7.4 4.0 | -20.0 -4.0 270 67 35 6.7 3.7
19500 -18.8 -1.8 265 63 33 7.4 4.0 | -19.0 -2.2 265 64 33 6.8 3.7
19000 -17.7 0.1 260 61 32 7.4 4.0 | -18.0 -0.4 265 61 31 6.8 3.7
18500 -16.6 2.1 260 60 31 6.8 3.7 | -17.0 1.4 265 58 30 6.7 3.7
18000 -15.7 3.7 260 58 30 6.1 3.4 | -16.0 3.2 265 57 29 6.7 3.7
17500 -14.8 5.4 260 57 29 6.1 3.4 | -15.1 4.8 260 55 28 6.7 3.7
17000 -13.9 7.0 260 55 29 6.0 3.3 | -14.0 6.8 260 54 28 7.2 3.9
16500 -13.1 8.4 260 53 27 6.0 3.3 | -13.0 8.6 260 53 27 7.3 4.0
16000 -12.2 10.0 260 51 26 6.4 3.5 | -12.0 10.4 260 52 27 5.7 3.1
15500 -11.2 11.8 260 49 25 6.5 3.6 | -11.2 11.8 260 51 26 5.4 3.0
15000 -10.2 13.6 260 47 24 6.3 3.5 | -10.5 13.1 260 50 26 5.3 2.9
14500 -9.3 15.3 260 46 23 6.1 3.4 | -9.7 14.5 260 48 25 5.1 2.8
14000 -8.4 16.9 255 44 23 6.0 3.3 | -9.0 15.8 260 46 23 5.3 2.9
13500 -7.6 18.3 255 42 22 5.6 3.1 | -8.2 17.2 260 43 22 5.9 3.2
13000 -6.7 19.9 255 40 20 5.6 3.1 | -7.3 18.9 255 41 21 5.9 3.2
12500 -5.9 21.4 255 37 19 6.1 3.3 | -6.4 20.5 255 38 20 6.2 3.4
12000 -5.0 23.0 255 35 18 6.0 3.3 | -5.5 22.1 255 36 18 6.3 3.4
11500 -4.0 24.8 250 34 18 7.0 3.9 | -4.5 23.9 255 34 18 7.2 4.0
11000 -3.0 26.6 250 35 18 7.0 3.8 | -3.4 25.9 250 34 17 7.1 3.9
10500 -2.0 28.4 250 35 18 6.1 3.3 | -2.4 27.7 250 33 17 6.4 3.5
10250 -1.6 29.1 250 35 18 6.2 3.4 | -1.9 28.6 250 33 17 6.7 3.7
10000 -1.1 30.0 250 36 18 7.8 4.3 | -1.4 29.5 250 32 17 8.9 4.9
9750 -0.4 31.3 245 36 18 8.4 4.6 | -0.7 30.7 250 31 16 9.0 4.9
9500 0.1 32.2 245 35 18 7.6 4.1 | -0.1 31.8 245 31 16 7.7 4.2
9250 1.3 34.3 240 34 18 7.5 4.1 | 0.5 32.9 245 30 15 8.1 4.4
9000 1.8 35.2 240 33 17 7.4 4.1 | 1.1 34.0 245 29 15 7.8 4.3
8750 2.4 36.3 235 31 16 7.9 4.3 | 2.4 36.3 245 28 14 8.9 4.9
8500 2.9 37.2 235 30 16 7.5 4.1 | 3.0 37.4 240 27 14 8.8 4.8
8250 3.5 38.3 235 29 15 8.5 4.7 | 3.7 38.7 240 26 13 8.8 4.8
8000 4.2 39.6 235 29 15 7.6 4.2 | 4.3 39.7 240 25 13 8.5 4.7
7750 4.6 40.3 230 26 14 6.0 3.3 | 5.0 41.0 240 23 12 8.3 4.6
7500 5.1 41.2 225 24 12 6.3 3.5 | 5.6 42.1 235 21 11 8.3 4.6
7250 5.5 41.9 225 22 11 6.3 3.4 | 6.2 43.2 235 20 10 7.9 4.3
7000 6.0 42.8 220 21 11 4.8 2.6 | 6.8 44.2 235 20 10 8.9 4.9
6750 6.3 43.3 215 18 9 4.1 2.2 | 7.5 45.5 235 18 9 9.8 5.4
6500 6.6 43.9 205 15 8 2.9 1.6 | 8.2 46.8 235 16 8 10.3 5.7
6250 6.7 44.1 195 13 6 1.1 0.6 | 9.1 48.4 235 16 8 12.3 6.7
6000 6.8 44.2 180 11 6 1.7 1.0 | 9.9 49.8 235 16 8 8.3 4.6
5750 6.6 43.9 175 9 4 -9.6 -5.2 | 10.4 50.7 235 14 7 7.5 4.1
5500 4.2 39.6 145 5 3 -66.4 -36.4 | 12.4 54.3 235 12 6 59.5 32.6
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
02/05/2025 at 1400 MST | 02/05/2025 at 1700 MST
|
CAPE... 0.0 LI... +3.3 | CAPE... +0.5 LI... +1.2
CINH... -0.0 K Index... +5.7 | CINH... -4.6 K Index... +9.1
|
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 -61.8 -79.2 260 64 33 2.8 1.5 | -62.3 -80.1 265 74 38 3.3 1.8
45000 -57.3 -71.1 265 100 52 5.8 3.2 | -57.0 -70.6 265 100 52 5.8 3.2
40000 -48.4 -55.1 270 127 66 5.6 3.1 | -48.3 -54.9 270 129 66 5.9 3.2
38000 -46.1 -51.0 270 134 69 3.1 1.7 | -45.5 -49.9 270 136 70 3.4 1.8
36000 -44.3 -47.7 270 139 71 3.1 1.7 | -43.4 -46.1 270 139 72 3.4 1.8
34000 -42.6 -44.7 270 140 72 2.4 1.3 | -41.6 -42.9 270 141 72 2.3 1.3
32000 -41.1 -42.0 270 132 68 2.4 1.3 | -40.2 -40.4 270 135 70 2.3 1.2
30000 -39.4 -38.9 265 122 63 4.9 2.7 | -38.7 -37.7 265 127 65 3.6 2.0
29000 -38.0 -36.4 265 115 59 4.8 2.6 | -37.6 -35.7 265 118 61 3.6 2.0
28000 -36.6 -33.9 265 107 55 4.8 2.6 | -36.6 -33.9 265 109 56 3.6 2.0
27000 -35.1 -31.2 260 100 51 4.9 2.7 | -35.5 -31.9 260 99 51 3.6 2.0
26000 -33.3 -27.9 260 95 49 6.1 3.4 | -34.1 -29.4 260 92 47 5.0 2.8
25000 -31.0 -23.8 265 89 46 6.1 3.4 | -32.5 -26.5 265 85 44 5.0 2.8
24000 -29.2 -20.6 265 85 44 6.6 3.6 | -30.6 -23.1 265 77 40 6.0 3.3
23000 -27.0 -16.6 265 81 42 7.3 4.0 | -28.4 -19.1 265 74 38 7.7 4.2
22000 -24.8 -12.6 265 78 40 7.3 4.0 | -26.1 -15.0 265 72 37 7.7 4.2
21000 -22.6 -8.7 265 74 38 7.4 4.1 | -23.8 -10.8 270 70 36 7.3 4.0
20000 -20.4 -4.7 265 70 36 7.4 4.1 | -21.7 -7.1 270 66 34 7.2 3.9
19500 -19.3 -2.7 265 68 35 7.4 4.1 | -20.6 -5.1 270 64 33 7.2 3.9
19000 -18.2 -0.8 265 67 34 7.4 4.1 | -19.5 -3.1 270 62 32 7.2 4.0
18500 -17.1 1.2 265 65 33 7.4 4.0 | -18.4 -1.1 270 60 31 7.3 4.0
18000 -16.0 3.2 265 63 32 7.3 4.0 | -17.3 0.9 270 58 30 7.5 4.1
17500 -14.9 5.2 265 61 32 7.3 4.0 | -16.2 2.8 270 56 29 7.5 4.1
17000 -13.9 7.0 265 59 31 6.2 3.4 | -15.1 4.8 270 54 28 7.2 4.0
16500 -12.9 8.8 265 57 29 6.4 3.5 | -14.1 6.6 265 52 27 7.3 4.0
16000 -12.0 10.4 265 55 28 6.1 3.3 | -13.0 8.6 265 49 25 7.0 3.8
15500 -11.1 12.0 260 52 27 6.1 3.3 | -12.0 10.4 265 47 24 6.9 3.8
15000 -10.2 13.6 260 50 26 5.8 3.2 | -11.0 12.2 265 45 23 6.8 3.7
14500 -9.5 14.9 260 48 25 5.5 3.0 | -10.0 14.0 265 43 22 6.7 3.7
14000 -8.7 16.3 260 46 24 5.6 3.1 | -9.0 15.8 265 41 21 6.7 3.7
13500 -7.9 17.8 260 43 22 6.0 3.3 | -8.1 17.4 265 40 21 6.8 3.7
13000 -7.1 19.2 260 41 21 6.1 3.4 | -7.1 19.2 260 39 20 6.9 3.8
12500 -6.1 21.0 260 39 20 7.4 4.1 | -6.1 21.0 260 37 19 7.2 4.0
12000 -5.0 23.0 255 37 19 7.4 4.0 | -5.1 22.8 260 36 18 7.3 4.0
11500 -3.9 25.0 255 35 18 7.4 4.1 | -3.9 25.0 260 34 18 9.0 4.9
11000 -2.8 27.0 250 33 17 7.4 4.1 | -2.6 27.3 255 33 17 8.8 4.8
10500 -1.7 28.9 250 32 16 6.9 3.8 | -1.4 29.5 255 31 16 7.9 4.3
10250 -1.2 29.8 250 31 16 7.8 4.3 | -0.8 30.6 255 30 16 9.0 4.9
10000 -0.5 31.1 250 30 16 10.4 5.7 | 0.0 32.0 255 30 15 11.2 6.1
9750 0.2 32.4 245 30 15 9.7 5.3 | 0.8 33.4 250 29 15 10.4 5.7
9500 0.9 33.6 245 29 15 8.3 4.6 | 1.5 34.7 250 29 15 9.3 5.1
9250 1.5 34.7 245 28 15 8.3 4.6 | 2.3 36.1 255 28 15 9.4 5.1
9000 2.2 36.0 245 28 14 9.8 5.4 | 3.0 37.4 255 28 14 10.1 5.5
8750 3.0 37.4 245 27 14 10.5 5.7 | 4.5 40.1 250 26 13 9.4 5.1
8500 4.4 39.9 245 26 14 9.8 5.4 | 5.2 41.4 250 25 13 9.4 5.2
8250 5.1 41.2 245 26 13 8.5 4.7 | 5.9 42.6 250 24 13 10.0 5.5
8000 5.7 42.3 245 26 13 9.1 5.0 | 6.6 43.9 255 24 13 9.8 5.4
7750 6.5 43.7 245 25 13 10.9 6.0 | 7.3 45.1 255 23 12 8.9 4.9
7500 7.3 45.1 245 24 13 9.9 5.4 | 8.0 46.4 255 21 11 9.0 5.0
7250 8.0 46.4 245 24 12 7.6 4.1 | 8.6 47.5 255 21 11 8.4 4.6
7000 8.5 47.3 245 25 13 9.3 5.1 | 9.3 48.7 255 21 11 8.7 4.8
6750 9.4 48.9 245 23 12 12.0 6.6 | 9.9 49.8 255 19 10 9.0 4.9
6500 10.2 50.4 245 22 11 10.7 5.8 | 10.6 51.1 255 17 9 9.5 5.2
6250 11.0 51.8 245 22 11 10.7 5.9 | 11.4 52.5 255 16 8 10.9 6.0
6000 11.8 53.2 250 22 11 8.7 4.8 | 12.1 53.8 255 16 8 8.2 4.5
5750 12.4 54.3 250 19 10 11.1 6.1 | 12.5 54.5 260 13 7 2.7 1.5
5500 14.5 58.1 250 16 8 56.8 31.2 | 12.9 55.2 255 9 5 12.5 6.9
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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