Soaring Guidance
Issued by NWS Grand Junction, CO
Issued by NWS Grand Junction, CO
861
UXUS97 KGJT 241306
SRGGJT
Soaring Forecast
National Weather Service Grand Junction, Colorado
606 AM MST Sunday, November 24, 2024
This forecast is for Sunday, November 24, 2024:
If the trigger temperature of 59.7 F/15.4 C is reached...then
Thermal Soaring Index....................... Poor
Maximum rate of lift........................ 0 ft/min (0.0 m/s)
Maximum height of thermals.................. 5372 ft MSL (533 ft AGL)
Forecast maximum temperature................... 53.0 F/12.1 C
Time of trigger temperature.................... None
Time of overdevelopment........................ 0800 MST
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................. 5155 ft MSL (316 ft AGL)
Thermal soaring outlook for Monday 11/25....... Fair
Wave Soaring Index............................. Not available
Remarks...
Sunrise/Sunset.................... 07:08:02 / 16:54:03 MST
Total possible sunshine........... 9 hr 46 min 1 sec (586 min 1 sec)
Altitude of sun at 12:01:02 MST... 30.13 degrees
Upper air data from rawinsonde observation taken on 11/24/2024 at 0500 MST
Freezing level.................. 10118 ft MSL (5279 ft AGL)
Convective condensation level... 18711 ft MSL (13872 ft AGL)
Lifted condensation level....... 14026 ft MSL (9187 ft AGL)
Lifted index.................... +12.0
K index......................... +8.2
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 -63.1 -81.6 250 54 28 5.1 2.8 96.1 205.0 48.0 M M
45000 -55.7 -68.3 240 76 39 -1.1 -0.6 82.5 180.6 43.3 M M
40000 -57.3 -71.1 260 94 48 2.0 1.1 57.0 134.6 29.7 M M
38000 -56.4 -69.5 260 105 54 3.6 2.0 49.5 121.1 25.4 M M
36000 -55.0 -67.0 250 110 57 -5.5 -3.0 43.1 109.5 21.7 M M
34000 -52.7 -62.9 250 107 55 7.9 4.3 37.9 100.2 18.6 M M
32000 -46.9 -52.4 255 105 54 8.9 4.9 36.8 98.2 18.3 M M
30000 -41.5 -42.7 255 105 54 9.2 5.0 36.2 97.2 18.4 M M
29000 -38.8 -37.8 260 104 54 9.2 5.0 36.0 96.7 18.4 M M
28000 -36.1 -33.0 260 102 53 8.6 4.7 35.6 96.1 18.4 M M
27000 -33.6 -28.5 255 95 49 8.3 4.6 35.0 95.0 18.1 M M
26000 -31.1 -24.0 255 88 45 8.3 4.6 34.5 94.1 18.0 M M
25000 -28.8 -19.8 250 81 42 7.0 3.8 33.7 92.7 17.6 M M
24000 -26.7 -16.1 245 83 43 7.0 3.8 32.7 90.8 16.9 M M
23000 -25.3 -13.5 255 74 38 3.4 1.9 30.9 87.6 15.6 M M
22000 -23.6 -10.5 255 75 38 5.4 3.0 29.4 84.8 14.5 M M
21000 -23.0 -9.4 245 70 36 4.7 2.6 26.6 79.8 12.4 M M
20000 -20.8 -5.4 245 67 35 6.8 3.8 25.7 78.3 11.9 M M
19500 -19.8 -3.6 245 64 33 6.7 3.7 25.2 77.3 11.4 M M
19000 -18.8 -1.8 240 62 32 7.7 4.2 24.7 76.4 11.0 M M
18500 -17.5 0.5 240 61 31 8.3 4.5 24.4 76.0 10.9 M M
18000 -16.3 2.7 240 61 32 8.3 4.6 24.2 75.5 10.8 M M
17500 -14.4 6.1 240 60 31 7.3 4.0 23.9 75.0 10.6 M M
17000 -13.2 8.2 240 57 30 7.7 4.2 23.5 74.3 10.3 M M
16500 -12.1 10.2 235 56 29 7.8 4.3 23.2 73.7 10.0 M M
16000 -11.3 11.7 240 55 28 4.1 2.3 22.5 72.4 9.4 M M
15500 -10.7 12.7 240 54 28 3.8 2.1 21.5 70.8 8.6 M M
15000 -10.1 13.8 235 46 24 3.9 2.1 20.5 69.0 7.7 M M
14500 -9.6 14.7 235 41 21 4.0 2.2 19.6 67.2 6.9 M M
14000 -9.1 15.6 240 34 18 4.0 2.2 18.6 65.5 6.0 M M
13500 -8.6 16.5 245 32 17 4.4 2.4 17.6 63.7 5.0 M M
13000 -7.5 18.5 245 30 16 9.0 4.9 17.2 63.0 4.7 M M
12500 -6.2 20.8 245 35 18 8.7 4.8 17.1 62.7 4.5 M M
12000 -4.9 23.2 240 34 18 8.7 4.8 16.9 62.4 4.4 M M
11500 -3.6 25.5 240 35 18 8.7 4.8 16.7 62.1 4.3 M M
11000 -2.3 27.9 240 37 19 8.7 4.8 16.6 61.8 4.2 M M
10500 -1.0 30.2 240 36 19 8.7 4.8 16.4 61.5 4.0 M M
10250 -0.3 31.5 240 36 18 8.7 4.8 16.3 61.3 3.9 M M
10000 0.3 32.5 240 35 18 8.7 4.8 16.2 61.2 3.9 M M
9750 1.0 33.8 240 35 18 8.5 4.7 16.1 61.0 3.8 M M
9500 1.6 34.9 235 35 18 8.5 4.7 16.0 60.9 3.7 M M
9250 2.3 36.1 240 34 18 8.5 4.7 15.9 60.7 3.7 M M
9000 2.9 37.2 235 30 16 8.5 4.7 15.9 60.6 3.6 M M
8750 3.6 38.5 235 27 14 8.5 4.7 15.8 60.4 3.5 M M
8500 4.2 39.6 230 25 13 8.5 4.7 15.7 60.2 3.5 M M
8250 4.8 40.6 225 22 11 8.5 4.7 15.6 60.0 3.4 M M
8000 5.5 41.9 220 19 10 8.5 4.7 15.5 59.9 3.3 M M
7750 6.1 43.0 220 18 9 8.5 4.7 15.4 59.7 3.3 M M
7500 6.8 44.2 215 15 8 8.5 4.7 15.3 59.5 3.2 M M
7250 7.4 45.3 205 12 6 8.5 4.7 15.2 59.4 3.1 M M
7000 8.1 46.6 195 9 5 8.5 4.7 15.1 59.2 3.0 M M
6750 8.7 47.7 190 10 5 8.6 4.7 15.0 59.0 2.9 M M
6500 9.4 48.9 180 10 5 8.4 4.6 14.9 58.8 2.9 M M
6250 10.0 50.0 175 10 5 9.0 4.9 14.8 58.6 2.8 M M
6000 10.7 51.3 165 10 5 6.9 3.8 14.7 58.5 2.7 M M
5750 11.2 52.2 160 10 5 8.1 4.5 14.4 58.0 2.4 M M
5500 11.5 52.7 150 10 5 -6.8 -3.7 14.0 57.3 2.0 M M
5250 9.8 49.6 150 8 4 -34.2 -18.8 11.6 52.9 -0.4 M M
5000 6.9 44.4 170 4 2 -37.9 -20.8 8.0 46.4 -4.0 47 0.2
* * * * * * Numerical weather prediction model forecast data valid * * * * * *
11/24/2024 at 0800 MST | 11/24/2024 at 1100 MST
|
CAPE... 0.0 LI... +4.7 | CAPE... 0.0 LI... +3.5
CINH... -0.1 K Index... +3.5 | CINH... -0.0 K Index... +10.4
|
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 -61.4 -78.5 255 60 31 2.1 1.1 | -60.6 -77.1 255 60 31 1.7 1.0
45000 -58.3 -72.9 255 77 40 1.8 1.0 | -58.0 -72.4 260 78 40 1.6 0.9
40000 -58.9 -74.0 260 114 59 -0.5 -0.2 | -59.5 -75.1 255 113 58 -1.1 -0.6
38000 -57.8 -72.0 260 124 64 5.3 2.9 | -58.5 -73.3 255 121 62 6.1 3.4
36000 -54.2 -65.6 260 127 65 5.3 2.9 | -54.3 -65.7 255 121 62 6.1 3.3
34000 -50.7 -59.3 260 128 66 8.0 4.4 | -50.6 -59.1 255 120 62 7.8 4.3
32000 -46.1 -51.0 260 120 62 7.8 4.3 | -46.0 -50.8 255 119 61 7.6 4.2
30000 -41.4 -42.5 260 113 58 7.0 3.9 | -41.4 -42.5 255 118 61 7.5 4.1
29000 -39.3 -38.7 260 109 56 7.2 3.9 | -39.2 -38.6 255 116 60 7.6 4.2
28000 -37.1 -34.8 260 105 54 7.2 3.9 | -36.9 -34.4 255 113 58 7.6 4.2
27000 -34.9 -30.8 260 100 52 7.2 3.9 | -34.6 -30.3 260 111 57 7.7 4.2
26000 -32.8 -27.0 260 96 50 7.2 3.9 | -32.6 -26.7 260 106 55 6.4 3.5
25000 -30.7 -23.3 255 92 48 7.2 3.9 | -30.7 -23.3 255 100 51 6.4 3.5
24000 -28.5 -19.3 255 88 46 7.2 4.0 | -28.7 -19.7 255 94 48 6.5 3.5
23000 -26.6 -15.9 255 84 43 5.8 3.2 | -26.4 -15.5 255 87 45 6.0 3.3
22000 -24.5 -12.1 250 79 40 5.8 3.2 | -24.7 -12.5 250 81 42 6.0 3.3
21000 -22.8 -9.0 250 74 38 5.4 3.0 | -22.9 -9.2 250 75 39 5.2 2.8
20000 -21.3 -6.3 245 69 35 5.0 2.7 | -21.6 -6.9 250 69 36 4.4 2.4
19500 -20.6 -5.1 245 66 34 5.0 2.7 | -21.0 -5.8 250 66 34 4.4 2.4
19000 -19.8 -3.6 245 63 33 5.1 2.8 | -20.3 -4.5 245 63 33 4.5 2.5
18500 -19.1 -2.4 245 60 31 5.5 3.0 | -19.7 -3.5 245 60 31 4.8 2.6
18000 -18.2 -0.8 245 58 30 6.8 3.7 | -18.9 -2.0 245 58 30 5.7 3.1
17500 -17.1 1.2 245 57 29 6.7 3.7 | -18.1 -0.6 245 55 28 5.7 3.1
17000 -16.1 3.0 245 55 28 7.2 4.0 | -17.2 1.0 245 53 27 6.1 3.4
16500 -15.0 5.0 245 53 27 7.2 4.0 | -16.3 2.7 245 51 26 6.2 3.4
16000 -14.0 6.8 245 51 26 7.1 3.9 | -15.4 4.3 245 49 25 6.3 3.4
15500 -12.9 8.8 245 50 26 7.0 3.8 | -14.5 5.9 245 48 25 6.3 3.5
15000 -11.9 10.6 245 48 25 6.8 3.7 | -13.5 7.7 245 46 24 6.3 3.4
14500 -11.0 12.2 245 46 24 5.9 3.3 | -12.6 9.3 245 45 23 6.1 3.3
14000 -10.1 13.8 245 44 23 6.0 3.3 | -11.7 10.9 245 43 22 6.1 3.4
13500 -9.2 15.4 245 41 21 5.5 3.0 | -10.8 12.6 240 41 21 6.1 3.3
13000 -8.4 16.9 245 39 20 5.5 3.0 | -10.0 14.0 240 39 20 6.1 3.3
12500 -7.6 18.3 245 37 19 6.0 3.3 | -9.0 15.8 240 37 19 6.9 3.8
12000 -6.7 19.9 245 36 19 5.9 3.2 | -8.0 17.6 240 35 18 6.7 3.7
11500 -5.7 21.7 240 35 18 7.3 4.0 | -7.0 19.4 240 33 17 7.8 4.3
11000 -4.6 23.7 240 34 17 7.4 4.0 | -5.8 21.6 240 31 16 7.8 4.3
10500 -3.6 25.5 240 33 17 6.4 3.5 | -4.7 23.5 240 30 15 6.8 3.8
10250 -3.1 26.4 240 33 17 6.4 3.5 | -4.2 24.4 240 29 15 6.8 3.7
10000 -2.6 27.3 240 32 17 10.2 5.6 | -3.6 25.5 240 28 14 10.6 5.8
9750 -1.7 28.9 240 32 16 10.1 5.6 | -2.7 27.1 235 28 14 10.7 5.9
9500 -1.1 30.0 240 31 16 7.2 4.0 | -2.0 28.4 235 27 14 7.9 4.3
9250 -0.5 31.1 240 31 16 7.8 4.3 | -1.4 29.5 235 26 13 8.4 4.6
9000 0.1 32.2 240 31 16 8.4 4.6 | -0.8 30.6 235 25 13 9.2 5.0
8750 0.7 33.3 235 29 15 8.5 4.7 | -0.0 32.0 235 25 13 9.3 5.1
8500 1.3 34.3 235 27 14 7.6 4.2 | 0.6 33.1 235 24 12 8.3 4.5
8250 2.5 36.5 230 24 13 7.1 3.9 | 1.9 35.4 235 23 12 7.7 4.2
8000 3.0 37.4 235 24 12 6.6 3.6 | 2.4 36.3 240 21 11 7.6 4.2
7750 3.5 38.3 230 22 11 7.1 3.9 | 3.1 37.6 235 19 10 8.6 4.7
7500 4.0 39.2 230 19 10 7.0 3.9 | 3.7 38.7 235 18 9 8.2 4.5
7250 4.5 40.1 225 18 9 5.9 3.3 | 4.2 39.6 240 17 9 6.1 3.3
7000 4.9 40.8 225 17 9 4.7 2.6 | 4.7 40.5 245 15 8 7.9 4.3
6750 5.3 41.5 220 15 7 5.3 2.9 | 5.4 41.7 240 14 7 10.7 5.9
6500 5.6 42.1 210 12 6 3.5 1.9 | 6.2 43.2 240 13 7 9.9 5.4
6250 5.8 42.4 200 10 5 0.0 0.0 | 7.0 44.6 245 12 6 10.7 5.9
6000 5.8 42.4 190 9 4 1.4 0.8 | 7.7 45.9 250 11 6 8.6 4.7
5750 5.7 42.3 180 6 3 -8.4 -4.6 | 8.3 46.9 245 11 6 9.4 5.1
5500 2.9 37.2 150 4 2 -84.1 -46.1 | 10.0 50.0 255 9 4 44.9 24.6
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
11/24/2024 at 1400 MST | 11/24/2024 at 1700 MST
|
CAPE... +0.4 LI... +3.0 | CAPE... 0.0 LI... +3.1
CINH... -1.4 K Index... +13.0 | CINH... -0.1 K Index... +12.9
|
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 -60.6 -77.1 255 61 32 1.6 0.9 | -60.1 -76.2 260 63 32 1.4 0.8
45000 -58.2 -72.8 260 80 41 1.5 0.8 | -58.0 -72.4 265 80 41 1.4 0.8
40000 -58.3 -72.9 260 110 56 -0.2 -0.1 | -57.5 -71.5 260 99 51 0.3 0.1
38000 -57.3 -71.1 260 116 60 5.0 2.7 | -56.5 -69.7 260 105 54 4.0 2.2
36000 -53.9 -65.0 260 114 59 4.9 2.7 | -53.9 -65.0 260 108 56 3.9 2.2
34000 -50.8 -59.4 255 112 58 7.7 4.2 | -51.3 -60.3 255 111 57 7.5 4.1
32000 -46.4 -51.5 255 112 57 7.4 4.0 | -47.0 -52.6 260 108 55 7.1 3.9
30000 -41.9 -43.4 255 111 57 7.7 4.2 | -42.7 -44.9 260 104 54 7.8 4.3
29000 -39.6 -39.3 255 109 56 7.7 4.2 | -40.5 -40.9 260 101 52 7.6 4.2
28000 -37.3 -35.1 255 107 55 7.7 4.2 | -38.2 -36.8 260 99 51 7.6 4.2
27000 -35.0 -31.0 255 105 54 7.9 4.3 | -36.0 -32.8 260 96 49 7.6 4.2
26000 -32.9 -27.2 255 102 52 6.7 3.7 | -33.7 -28.7 260 93 48 7.2 4.0
25000 -30.9 -23.6 255 98 50 6.7 3.7 | -31.6 -24.9 260 89 46 7.2 4.0
24000 -28.9 -20.0 255 94 48 6.7 3.7 | -29.4 -20.9 260 86 44 7.2 4.0
23000 -27.1 -16.8 255 89 46 5.4 3.0 | -27.5 -17.5 260 82 42 5.9 3.2
22000 -25.1 -13.2 255 82 42 5.4 3.0 | -25.3 -13.5 260 77 40 5.9 3.2
21000 -23.5 -10.3 255 77 39 5.0 2.7 | -23.5 -10.3 260 73 37 4.8 2.6
20000 -22.2 -8.0 250 69 36 4.3 2.4 | -22.5 -8.5 260 66 34 3.2 1.7
19500 -21.5 -6.7 250 66 34 4.3 2.4 | -22.1 -7.8 255 63 32 3.2 1.7
19000 -20.9 -5.6 250 62 32 4.4 2.4 | -21.6 -6.9 255 60 31 3.2 1.8
18500 -20.2 -4.4 250 58 30 4.5 2.5 | -21.2 -6.2 255 56 29 3.5 1.9
18000 -19.5 -3.1 250 55 28 5.1 2.8 | -20.5 -4.9 255 53 27 4.7 2.6
17500 -18.8 -1.8 250 52 27 5.1 2.8 | -19.9 -3.8 255 49 25 4.6 2.5
17000 -18.0 -0.4 250 48 25 5.6 3.1 | -19.1 -2.4 255 46 24 6.0 3.3
16500 -17.2 1.0 245 46 24 5.7 3.1 | -18.2 -0.8 255 43 22 6.1 3.4
16000 -16.4 2.5 245 43 22 5.8 3.2 | -17.3 0.9 255 40 21 6.3 3.5
15500 -15.5 4.1 245 41 21 5.8 3.2 | -16.4 2.5 255 38 19 6.4 3.5
15000 -14.7 5.5 245 39 20 5.9 3.2 | -15.5 4.1 255 35 18 6.6 3.6
14500 -13.8 7.2 245 37 19 6.2 3.4 | -14.5 5.9 255 33 17 7.0 3.8
14000 -12.9 8.8 245 36 18 6.2 3.4 | -13.4 7.9 255 31 16 7.0 3.8
13500 -11.9 10.6 245 34 17 6.9 3.8 | -12.5 9.5 255 29 15 6.6 3.6
13000 -10.9 12.4 245 32 16 6.8 3.7 | -11.5 11.3 255 27 14 6.7 3.7
12500 -9.8 14.4 245 30 16 8.0 4.4 | -10.5 13.1 250 25 13 6.3 3.5
12000 -8.7 16.3 245 29 15 7.9 4.3 | -9.6 14.7 250 23 12 6.3 3.5
11500 -7.5 18.5 245 28 14 7.9 4.3 | -8.6 16.5 250 21 11 7.1 3.9
11000 -6.4 20.5 245 28 14 8.0 4.4 | -7.6 18.3 250 19 10 7.1 3.9
10500 -5.3 22.5 245 27 14 6.5 3.6 | -6.6 20.1 255 18 9 6.6 3.6
10250 -4.8 23.4 245 26 13 6.5 3.6 | -6.1 21.0 255 18 9 5.8 3.2
10000 -4.3 24.3 245 26 13 9.6 5.3 | -5.6 21.9 255 17 9 9.0 5.0
9750 -3.4 25.9 245 25 13 10.0 5.5 | -4.8 23.4 260 15 8 9.5 5.2
9500 -2.8 27.0 245 25 13 7.8 4.3 | -4.3 24.3 265 15 7 6.5 3.6
9250 -2.2 28.0 245 25 13 8.0 4.4 | -3.8 25.2 265 14 7 7.6 4.1
9000 -1.6 29.1 245 24 12 9.4 5.1 | -3.2 26.2 270 13 7 6.4 3.5
8750 -0.8 30.6 245 24 12 9.9 5.4 | -2.8 27.0 270 13 7 7.3 4.0
8500 0.5 32.9 245 23 12 9.1 5.0 | -1.5 29.3 280 12 6 8.8 4.8
8250 1.2 34.2 245 22 11 8.6 4.7 | -0.9 30.4 285 11 6 7.2 4.0
8000 1.8 35.2 245 23 12 8.6 4.7 | -0.4 31.3 285 11 6 7.0 3.8
7750 2.5 36.5 245 21 11 9.0 5.0 | 0.2 32.4 290 10 5 8.5 4.7
7500 3.2 37.8 245 20 10 8.8 4.8 | 0.9 33.6 300 10 5 7.8 4.3
7250 3.8 38.8 245 20 10 6.7 3.7 | 1.4 34.5 305 9 5 6.7 3.7
7000 4.3 39.7 250 20 10 7.8 4.3 | 1.9 35.4 305 10 5 6.9 3.8
6750 5.0 41.0 250 18 9 10.1 5.6 | 2.5 36.5 315 9 4 7.4 4.1
6500 5.7 42.3 250 16 8 9.4 5.1 | 3.0 37.4 320 8 4 7.8 4.3
6250 6.4 43.5 255 17 9 10.1 5.5 | 3.6 38.5 320 8 4 8.8 4.8
6000 7.1 44.8 255 17 9 7.9 4.3 | 4.3 39.7 315 7 4 7.1 3.9
5750 7.7 45.9 255 14 7 7.8 4.3 | 4.6 40.3 325 6 3 3.1 1.7
5500 9.1 48.4 255 12 6 41.3 22.7 | 4.9 40.8 305 4 2 6.8 3.7
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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