Soaring Guidance
Issued by NWS Grand Junction, CO
Issued by NWS Grand Junction, CO
867
UXUS97 KGJT 261306
SRGGJT
Soaring Forecast
National Weather Service Grand Junction, Colorado
606 AM MST Tuesday, November 26, 2024
This forecast is for Tuesday, November 26, 2024:
If the trigger temperature of 49.0 F/9.5 C is reached...then
Thermal Soaring Index....................... Poor
Maximum rate of lift........................ 0 ft/min (0.0 m/s)
Maximum height of thermals.................. 6874 ft MSL (2035 ft AGL)
Forecast maximum temperature................... 42.0 F/6.0 C
Time of trigger temperature.................... None
Time of overdevelopment........................ None
Middle/high clouds during soaring window....... Broken/overcast opaque middle
Surface winds during soaring window............ 20 mph or less
Height of the -3 thermal index................. 5821 ft MSL (982 ft AGL)
Thermal soaring outlook for Wednesday 11/27.... Poor
Wave Soaring Index............................. Not available
Remarks...
Sunrise/Sunset.................... 07:10:07 / 16:53:13 MST
Total possible sunshine........... 9 hr 43 min 6 sec (583 min 6 sec)
Altitude of sun at 12:01:40 MST... 29.75 degrees
Upper air data from rawinsonde observation taken on 11/26/2024 at 0500 MST
Freezing level.................. 4938 ft MSL (99 ft AGL)
Convective condensation level... 12437 ft MSL (7598 ft AGL)
Lifted condensation level....... 8092 ft MSL (3252 ft AGL)
Lifted index.................... +13.5
K index......................... +14.2
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 -60.3 -76.5 280 71 36 0.2 0.1 103.7 218.7 55.5 M M
45000 -62.1 -79.8 285 99 51 -0.8 -0.4 74.2 165.6 41.7 M M
40000 -64.8 -84.6 295 116 60 -2.0 -1.1 46.6 116.0 26.8 M M
38000 -63.5 -82.3 285 117 60 6.5 3.6 39.8 103.7 23.0 M M
36000 -58.4 -73.1 285 113 58 9.6 5.3 38.6 101.5 22.8 M M
34000 -53.2 -63.8 285 109 56 8.7 4.8 37.7 99.9 22.7 M M
32000 -47.3 -53.1 280 107 55 8.4 4.6 36.8 98.3 22.8 M M
30000 -42.1 -43.8 275 100 51 8.7 4.8 36.0 96.9 22.8 M M
29000 -39.4 -38.9 270 97 50 8.8 4.8 35.7 96.2 22.8 M M
28000 -36.8 -34.2 270 97 50 8.8 4.8 35.2 95.4 22.7 M M
27000 -34.2 -29.6 270 96 49 8.8 4.8 34.8 94.7 22.7 M M
26000 -31.7 -25.1 270 96 49 8.3 4.5 34.3 93.8 22.5 M M
25000 -29.2 -20.6 270 94 48 8.3 4.5 33.7 92.7 22.3 M M
24000 -26.8 -16.2 270 92 47 7.2 3.9 33.1 91.6 22.1 M M
23000 -25.0 -13.0 265 80 41 6.0 3.3 31.8 89.2 21.2 M M
22000 -23.2 -9.8 265 80 41 6.8 3.7 30.4 86.8 20.3 M M
21000 -21.2 -6.2 265 75 39 6.9 3.8 29.4 84.8 19.7 M M
20000 -19.1 -2.4 260 65 33 6.9 3.8 28.3 83.0 19.0 M M
19500 -18.1 -0.6 260 62 32 6.9 3.8 27.8 82.1 18.6 M M
19000 -17.3 0.9 255 59 31 4.9 2.7 27.1 80.8 18.1 M M
18500 -16.5 2.3 255 57 29 5.5 3.0 26.3 79.3 17.5 M M
18000 -15.6 3.9 250 51 26 6.1 3.4 25.6 78.2 17.0 M M
17500 -14.5 5.9 255 48 25 3.7 2.0 24.4 76.0 16.1 M M
17000 -13.8 7.2 250 47 24 5.8 3.2 23.6 74.5 15.5 M M
16500 -12.9 8.8 250 45 23 6.0 3.3 22.9 73.3 15.0 M M
16000 -12.0 10.4 255 43 22 6.0 3.3 22.3 72.2 14.5 M M
15500 -11.2 11.8 255 42 22 6.0 3.3 21.7 71.0 14.0 M M
15000 -10.3 13.5 255 41 21 5.7 3.1 21.1 69.9 13.5 M M
14500 -9.5 14.9 260 43 22 5.4 3.0 20.3 68.6 12.9 M M
14000 -8.7 16.3 265 44 23 5.4 3.0 19.6 67.3 12.3 M M
13500 -7.9 17.8 260 42 22 5.4 3.0 18.9 66.0 11.7 M M
13000 -7.1 19.2 265 39 20 5.4 3.0 18.2 64.7 11.1 M M
12500 -6.4 20.5 255 36 19 5.5 3.0 17.5 63.4 10.4 M M
12000 -5.7 21.7 250 44 23 3.9 2.2 16.7 62.0 9.7 M M
11500 -5.1 22.8 250 43 22 1.9 1.0 15.7 60.3 8.9 M M
11000 -4.8 23.4 240 36 19 3.0 1.7 14.4 58.0 7.7 M M
10500 -4.5 23.9 245 34 17 2.7 1.5 13.3 55.9 6.7 M M
10250 -4.3 24.3 245 30 15 2.7 1.5 12.7 54.9 6.2 M M
10000 -4.0 24.8 240 26 13 3.7 2.0 12.2 54.0 5.7 M M
9750 -3.7 25.3 245 24 13 4.4 2.4 11.8 53.2 5.3 M M
9500 -3.4 25.9 235 22 11 4.2 2.3 11.3 52.4 4.9 M M
9250 -3.1 26.4 230 19 10 4.3 2.3 10.9 51.6 4.5 M M
9000 -2.8 27.0 230 16 8 4.1 2.2 10.5 50.8 4.1 M M
8750 -2.5 27.5 235 16 8 3.8 2.1 10.0 50.0 3.6 M M
8500 -2.3 27.9 235 12 6 3.7 2.0 9.5 49.1 3.2 M M
8250 -2.0 28.4 240 8 4 3.7 2.0 9.1 48.3 2.7 M M
8000 -1.7 28.9 215 6 3 3.7 2.0 8.6 47.5 2.3 M M
7750 -1.5 29.3 190 7 4 3.7 2.0 8.1 46.6 1.8 M M
7500 -1.2 29.8 175 9 4 3.8 2.1 7.7 45.8 1.4 M M
7250 -0.9 30.4 165 10 5 3.7 2.0 7.2 44.9 0.9 M M
7000 -0.7 30.7 155 13 6 3.2 1.8 6.7 44.1 0.4 M M
6750 -0.5 31.1 155 11 6 -1.0 -0.5 6.1 43.0 -0.2 142 0.7
6500 -0.7 30.7 155 9 4 -3.6 -2.0 5.1 41.2 -1.1 141 0.7
6250 -0.8 30.6 145 5 3 1.0 0.5 4.2 39.6 -1.9 137 0.7
6000 -0.6 30.9 185 1 1 3.5 1.9 3.7 38.7 -2.5 123 0.6
5750 -0.4 31.3 200 1 0 2.4 1.3 3.2 37.8 -3.0 110 0.6
5500 -0.3 31.5 345 1 0 0.8 0.4 2.6 36.7 -3.6 98 0.5
5250 -0.3 31.5 360 2 1 -1.0 -0.5 1.8 35.3 -4.3 91 0.5
5000 -0.3 31.5 360 3 2 1.8 1.0 1.1 34.0 -5.1 84 0.4
* * * * * * Numerical weather prediction model forecast data valid * * * * * *
11/26/2024 at 0800 MST | 11/26/2024 at 1100 MST
|
CAPE... +0.3 LI... +3.0 | CAPE... +2.0 LI... +3.7
CINH... 0.0 K Index... +17.7 | CINH... -0.3 K Index... +17.8
|
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 -62.9 -81.2 275 70 36 0.1 0.1 | -62.1 -79.8 275 68 35 -0.2 -0.1
45000 -62.7 -80.9 280 95 49 0.1 0.0 | -62.3 -80.1 280 88 45 -0.2 -0.1
40000 -62.7 -80.9 275 97 50 -0.0 -0.0 | -62.9 -81.2 270 94 49 -0.4 -0.2
38000 -60.6 -77.1 275 99 51 7.0 3.8 | -60.6 -77.1 270 97 50 7.8 4.3
36000 -55.9 -68.6 275 101 52 7.0 3.8 | -55.4 -67.7 270 99 51 7.8 4.3
34000 -51.4 -60.5 275 102 53 8.4 4.6 | -50.7 -59.3 270 99 51 7.9 4.3
32000 -46.4 -51.5 275 99 51 8.4 4.6 | -45.9 -50.6 270 94 48 7.9 4.3
30000 -41.3 -42.3 275 96 49 8.6 4.7 | -41.2 -42.2 270 90 46 8.1 4.5
29000 -38.8 -37.8 275 95 49 8.6 4.7 | -38.8 -37.8 270 88 46 8.1 4.5
28000 -36.2 -33.2 275 93 48 8.6 4.7 | -36.3 -33.3 265 87 45 8.1 4.5
27000 -33.7 -28.7 275 92 48 8.1 4.4 | -33.9 -29.0 265 85 44 8.1 4.4
26000 -31.4 -24.5 275 91 47 7.7 4.2 | -31.5 -24.7 265 84 43 8.0 4.4
25000 -29.1 -20.4 270 90 46 7.7 4.2 | -29.2 -20.6 265 84 43 8.0 4.4
24000 -26.8 -16.2 270 88 45 7.5 4.1 | -26.8 -16.2 265 83 43 7.9 4.3
23000 -25.0 -13.0 270 83 43 5.7 3.1 | -24.2 -11.6 265 80 41 6.7 3.7
22000 -22.9 -9.2 270 75 39 5.7 3.1 | -22.3 -8.1 265 77 40 6.7 3.7
21000 -21.2 -6.2 265 69 36 6.2 3.4 | -20.4 -4.7 265 74 38 5.9 3.3
20000 -19.4 -2.9 265 64 33 6.1 3.4 | -18.6 -1.5 265 69 36 6.0 3.3
19500 -18.5 -1.3 265 61 32 6.1 3.4 | -17.7 0.1 260 67 34 6.0 3.3
19000 -17.6 0.3 260 59 30 6.1 3.4 | -16.8 1.8 260 64 33 6.0 3.3
18500 -16.7 1.9 260 56 29 6.4 3.5 | -16.0 3.2 260 62 32 5.8 3.2
18000 -15.8 3.6 260 55 28 6.5 3.5 | -15.1 4.8 260 59 31 5.8 3.2
17500 -14.8 5.4 260 53 27 6.5 3.6 | -14.3 6.3 260 57 29 5.8 3.2
17000 -13.8 7.2 260 52 27 6.8 3.7 | -13.4 7.9 255 55 28 5.9 3.2
16500 -12.8 9.0 255 50 26 6.9 3.8 | -12.6 9.3 255 52 27 5.9 3.2
16000 -11.9 10.6 255 49 25 6.1 3.3 | -11.7 10.9 255 50 26 6.2 3.4
15500 -11.0 12.2 255 48 25 6.1 3.4 | -10.8 12.6 255 49 25 6.2 3.4
15000 -10.1 13.8 255 46 24 6.1 3.3 | -9.9 14.2 255 48 24 6.1 3.3
14500 -9.2 15.4 255 45 23 6.1 3.3 | -9.0 15.8 255 46 24 6.0 3.3
14000 -8.3 17.1 255 44 23 5.8 3.2 | -8.1 17.4 255 45 23 5.6 3.1
13500 -7.5 18.5 255 43 22 5.5 3.0 | -7.4 18.7 255 43 22 4.8 2.6
13000 -6.7 19.9 255 42 22 5.2 2.8 | -6.7 19.9 255 41 21 4.6 2.5
12500 -6.1 21.0 255 41 21 4.2 2.3 | -6.1 21.0 255 39 20 3.9 2.1
12000 -5.5 22.1 250 40 21 4.1 2.2 | -5.5 22.1 255 37 19 3.9 2.1
11500 -5.0 23.0 250 38 20 3.0 1.7 | -5.0 23.0 250 34 18 3.4 1.9
11000 -4.5 23.9 250 36 19 3.0 1.7 | -4.5 23.9 250 31 16 3.4 1.9
10500 -4.1 24.6 245 33 17 2.7 1.5 | -4.0 24.8 250 29 15 3.2 1.8
10250 -3.9 25.0 245 32 16 2.5 1.4 | -3.8 25.2 245 29 15 3.1 1.7
10000 -3.7 25.3 245 30 16 3.2 1.8 | -3.6 25.5 245 28 14 3.8 2.1
9750 -3.5 25.7 240 27 14 3.5 1.9 | -3.3 26.1 245 25 13 3.8 2.1
9500 -3.2 26.2 240 25 13 3.0 1.7 | -3.0 26.6 245 23 12 3.1 1.7
9250 -3.0 26.6 240 23 12 3.2 1.8 | -2.8 27.0 245 22 11 3.3 1.8
9000 -2.8 27.0 235 21 11 2.9 1.6 | -2.6 27.3 240 21 11 3.2 1.8
8750 -2.6 27.3 235 19 10 3.3 1.8 | -2.3 27.9 240 19 10 3.8 2.1
8500 -2.3 27.9 235 17 9 3.9 2.1 | -2.0 28.4 240 17 9 4.2 2.3
8250 -1.8 28.8 230 14 7 3.4 1.9 | -1.7 28.9 235 16 8 4.0 2.2
8000 -1.5 29.3 230 12 6 3.8 2.1 | -1.3 29.7 235 11 6 3.8 2.1
7750 -1.2 29.8 225 11 6 4.5 2.5 | -0.9 30.4 230 10 5 5.9 3.2
7500 -0.9 30.4 220 10 5 3.6 2.0 | -0.5 31.1 225 8 4 3.8 2.1
7250 -0.7 30.7 215 8 4 1.9 1.1 | -0.4 31.3 220 6 3 0.7 0.4
7000 -0.5 31.1 210 7 3 4.3 2.4 | -0.3 31.5 215 4 2 3.7 2.0
6750 -0.1 31.8 210 6 3 5.7 3.1 | 0.2 32.4 210 4 2 5.9 3.2
6500 0.2 32.4 200 4 2 3.5 1.9 | 0.5 32.9 205 3 1 3.6 2.0
6250 0.4 32.7 190 4 2 2.0 1.1 | 0.7 33.3 185 2 1 1.7 1.0
6000 0.6 33.1 165 3 1 5.5 3.0 | 0.9 33.6 130 1 1 6.4 3.5
5750 1.2 34.2 160 2 1 9.5 5.2 | 1.7 35.1 145 1 0 14.5 7.9
5500 1.1 34.0 000 0 0 -23.3 -12.8 | 2.0 35.6 040 1 0 -17.3 -9.5
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
11/26/2024 at 1400 MST | 11/26/2024 at 1700 MST
|
CAPE... +1.2 LI... +3.6 | CAPE... +0.8 LI... +2.5
CINH... -0.8 K Index... +19.1 | CINH... 0.0 K Index... +20.1
|
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 -61.7 -79.1 275 68 35 0.3 0.2 | -61.5 -78.7 275 70 36 0.8 0.5
45000 -61.3 -78.3 275 88 45 0.1 0.1 | -60.3 -76.5 270 85 44 0.5 0.3
40000 -62.2 -80.0 265 98 50 -0.6 -0.3 | -62.0 -79.6 265 99 51 -1.2 -0.6
38000 -59.7 -75.5 265 101 52 7.4 4.0 | -60.5 -76.9 265 102 53 6.8 3.7
36000 -55.3 -67.5 270 101 52 7.4 4.0 | -56.0 -68.8 265 103 53 6.8 3.7
34000 -50.8 -59.4 270 100 51 8.0 4.4 | -51.7 -61.1 270 102 53 8.0 4.4
32000 -46.0 -50.8 265 94 48 8.0 4.4 | -46.9 -52.4 270 97 50 8.1 4.4
30000 -41.2 -42.2 265 89 46 8.0 4.4 | -42.0 -43.6 270 91 47 8.3 4.5
29000 -38.8 -37.8 265 87 45 8.0 4.4 | -39.6 -39.3 270 89 46 8.3 4.6
28000 -36.4 -33.5 265 85 44 8.0 4.4 | -37.1 -34.8 270 86 44 8.3 4.6
27000 -34.0 -29.2 265 84 43 7.8 4.3 | -34.6 -30.3 270 83 43 8.3 4.6
26000 -31.8 -25.2 265 81 42 7.5 4.1 | -32.1 -25.8 270 81 42 8.2 4.5
25000 -29.6 -21.3 265 79 41 7.5 4.1 | -29.7 -21.5 270 80 41 8.2 4.5
24000 -27.3 -17.1 265 77 40 7.5 4.1 | -27.3 -17.1 270 78 40 8.3 4.6
23000 -24.7 -12.5 265 75 39 7.2 3.9 | -25.1 -13.2 270 75 39 7.1 3.9
22000 -22.5 -8.5 265 74 38 7.2 3.9 | -22.5 -8.5 270 72 37 7.1 3.9
21000 -20.5 -4.9 265 72 37 6.4 3.5 | -20.5 -4.9 270 69 36 5.9 3.3
20000 -18.6 -1.5 265 68 35 6.4 3.5 | -18.8 -1.8 265 64 33 5.8 3.2
19500 -17.7 0.1 265 66 34 6.4 3.5 | -17.9 -0.2 265 62 32 5.8 3.2
19000 -16.7 1.9 260 64 33 6.4 3.5 | -17.1 1.2 265 59 31 5.8 3.2
18500 -15.8 3.6 260 62 32 6.5 3.6 | -16.2 2.8 265 57 29 6.1 3.4
18000 -14.8 5.4 260 60 31 6.5 3.6 | -15.3 4.5 265 55 28 6.3 3.5
17500 -13.9 7.0 260 59 30 6.5 3.6 | -14.4 6.1 260 53 27 6.3 3.5
17000 -12.9 8.8 260 58 30 6.4 3.5 | -13.4 7.9 260 52 27 6.8 3.7
16500 -12.0 10.4 260 57 29 6.4 3.5 | -12.4 9.7 260 50 26 6.8 3.7
16000 -11.1 12.0 260 55 28 6.1 3.3 | -11.4 11.5 260 49 25 6.6 3.6
15500 -10.2 13.6 255 54 28 6.0 3.3 | -10.5 13.1 255 48 25 6.5 3.6
15000 -9.3 15.3 255 52 27 5.7 3.1 | -9.5 14.9 255 47 24 6.2 3.4
14500 -8.5 16.7 255 50 26 5.4 3.0 | -8.7 16.3 255 46 24 5.6 3.1
14000 -7.8 18.0 255 48 25 5.1 2.8 | -7.9 17.8 255 45 23 5.5 3.0
13500 -7.1 19.2 255 45 23 4.2 2.3 | -7.1 19.2 255 44 22 5.3 2.9
13000 -6.5 20.3 255 42 21 4.2 2.3 | -6.4 20.5 255 42 21 5.3 2.9
12500 -5.9 21.4 255 38 20 3.6 2.0 | -5.7 21.7 250 40 20 4.1 2.3
12000 -5.4 22.3 250 35 18 3.6 2.0 | -5.1 22.8 250 37 19 4.2 2.3
11500 -4.8 23.4 250 33 17 3.9 2.1 | -4.5 23.9 250 35 18 4.1 2.2
11000 -4.3 24.3 250 31 16 3.9 2.1 | -3.9 25.0 250 33 17 4.1 2.3
10500 -3.7 25.3 250 29 15 3.7 2.0 | -3.3 26.1 245 32 16 3.7 2.0
10250 -3.5 25.7 245 29 15 3.6 2.0 | -3.0 26.6 245 31 16 3.5 1.9
10000 -3.2 26.2 245 28 14 3.8 2.1 | -2.8 27.0 245 31 16 4.6 2.5
9750 -2.9 26.8 245 25 13 3.7 2.0 | -2.4 27.7 245 28 14 4.5 2.5
9500 -2.7 27.1 245 24 12 3.5 1.9 | -2.2 28.0 245 26 13 3.1 1.7
9250 -2.4 27.7 245 23 12 3.5 1.9 | -1.9 28.6 245 24 12 3.7 2.0
9000 -2.2 28.0 240 22 11 3.7 2.0 | -1.7 28.9 240 23 12 2.5 1.4
8750 -1.9 28.6 240 21 11 3.8 2.1 | -1.5 29.3 245 22 11 2.7 1.5
8500 -1.4 29.5 240 17 9 3.7 2.0 | -1.2 29.8 240 20 10 3.9 2.1
8250 -1.1 30.0 235 15 7 3.1 1.7 | -0.7 30.7 240 15 8 2.5 1.3
8000 -0.9 30.4 240 13 7 3.6 2.0 | -0.6 30.9 240 14 7 2.3 1.3
7750 -0.6 30.9 235 11 6 4.8 2.6 | -0.3 31.5 235 11 6 4.0 2.2
7500 -0.3 31.5 230 9 5 3.7 2.0 | -0.1 31.8 235 9 4 3.2 1.8
7250 -0.1 31.8 230 7 4 0.9 0.5 | 0.1 32.2 230 7 3 0.3 0.2
7000 -0.0 32.0 230 5 2 2.7 1.5 | 0.1 32.2 230 5 3 1.8 1.0
6750 0.3 32.5 220 4 2 5.3 2.9 | 0.4 32.7 225 4 2 5.1 2.8
6500 0.7 33.3 210 3 1 3.5 1.9 | 0.7 33.3 215 2 1 3.3 1.8
6250 0.9 33.6 200 1 1 1.6 0.9 | 0.9 33.6 210 1 0 1.3 0.7
6000 1.0 33.8 085 1 0 5.6 3.1 | 1.1 34.0 045 1 0 5.0 2.7
5750 1.7 35.1 160 1 0 12.2 6.7 | 1.6 34.9 040 1 0 9.8 5.4
5500 2.0 35.6 045 1 0 -14.0 -7.7 | 1.7 35.1 010 1 1 -19.2 -10.5
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
________________________________________________________________________________
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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