Soaring Guidance
Issued by NWS Grand Junction, CO
Issued by NWS Grand Junction, CO
886
UXUS97 KGJT 141306
SRGGJT
Soaring Forecast
National Weather Service Grand Junction, Colorado
606 AM MST Thursday, November 14, 2024
This forecast is for Thursday, November 14, 2024:
If the trigger temperature of 58.0 F/14.5 C is reached...then
Thermal Soaring Index....................... Fair
Maximum rate of lift........................ 220 ft/min (1.1 m/s)
Maximum height of thermals.................. 8191 ft MSL (3352 ft AGL)
Forecast maximum temperature................... 56.0 F/13.8 C
Time of trigger temperature.................... None
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................. 7083 ft MSL (2244 ft AGL)
Thermal soaring outlook for Friday 11/15....... Fair
Wave Soaring Index............................. Not available
Remarks...
Sunrise/Sunset.................... 06:57:06 / 17:00:12 MST
Total possible sunshine........... 10 hr 3 min 6 sec (603 min 6 sec)
Altitude of sun at 11:58:39 MST... 32.38 degrees
Upper air data from rawinsonde observation taken on 11/14/2024 at 0500 MST
Freezing level.................. 11086 ft MSL (6247 ft AGL)
Convective condensation level... 20548 ft MSL (15709 ft AGL)
Lifted condensation level....... 14044 ft MSL (9205 ft AGL)
Lifted index.................... +12.5
K index......................... -26.3
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 -62.6 -80.7 255 73 38 -8.1 -4.4 95.7 204.3 47.0 M M
45000 -60.4 -76.7 255 89 46 5.0 2.8 74.5 166.0 37.4 M M
40000 -56.6 -69.9 260 90 46 7.9 4.3 56.2 133.2 28.2 M M
38000 -55.7 -68.3 260 90 46 7.2 3.9 48.8 119.8 23.9 M M
36000 -51.4 -60.5 255 91 47 7.3 4.0 46.7 116.1 23.1 M M
34000 -46.8 -52.2 255 93 48 8.2 4.5 44.8 112.7 22.4 M M
32000 -41.7 -43.1 260 93 48 8.7 4.7 43.8 110.8 22.2 M M
30000 -37.0 -34.6 255 90 46 6.8 3.8 41.3 106.4 21.0 M M
29000 -34.8 -30.6 260 88 46 8.2 4.5 40.3 104.6 20.5 M M
28000 -32.7 -26.9 260 86 44 2.6 1.4 39.3 102.7 20.0 M M
27000 -31.5 -24.7 260 80 41 6.4 3.5 37.1 98.7 18.5 M M
26000 -29.6 -21.3 260 75 38 6.0 3.3 35.7 96.2 17.6 M M
25000 -27.7 -17.9 255 70 36 9.0 5.0 34.5 94.1 16.8 M M
24000 -25.1 -13.2 255 66 34 8.6 4.7 34.1 93.4 16.7 M M
23000 -22.5 -8.5 255 65 33 8.6 4.7 33.7 92.6 16.6 M M
22000 -19.9 -3.8 250 62 32 8.5 4.7 33.2 91.8 16.4 M M
21000 -17.9 -0.2 250 63 32 5.1 2.8 32.3 90.1 15.8 M M
20000 -16.2 2.8 260 58 30 5.9 3.2 30.8 87.5 14.7 M M
19500 -15.3 4.5 260 56 29 5.2 2.8 30.1 86.1 14.2 M M
19000 -14.3 6.3 260 55 28 9.1 5.0 29.6 85.3 13.8 M M
18500 -13.0 8.6 260 56 29 7.9 4.3 29.4 84.9 13.7 M M
18000 -11.9 10.6 255 53 27 8.0 4.4 29.1 84.3 13.5 M M
17500 -10.6 12.9 255 54 28 8.4 4.6 28.8 83.8 13.3 M M
17000 -9.4 15.1 250 50 26 7.4 4.0 28.5 83.3 13.2 M M
16500 -7.8 18.0 250 47 24 7.4 4.1 27.9 82.1 12.7 M M
16000 -6.7 19.9 250 45 23 7.5 4.1 27.5 81.5 12.5 M M
15500 -5.5 22.1 250 43 22 7.5 4.1 27.1 80.8 12.2 M M
15000 -4.4 24.1 245 46 24 7.7 4.2 26.7 80.1 12.0 M M
14500 -3.2 26.2 245 46 24 8.5 4.7 26.4 79.6 11.7 M M
14000 -2.4 27.7 245 42 22 -1.1 -0.6 25.7 78.2 11.1 M M
13500 -2.6 27.3 245 39 20 3.0 1.6 23.9 75.0 9.6 M M
13000 -1.9 28.6 240 35 18 4.6 2.5 23.0 73.4 8.8 M M
12500 -1.2 29.8 235 31 16 5.2 2.9 22.2 72.0 8.1 M M
12000 -0.5 31.1 230 27 14 0.6 0.4 21.4 70.5 7.4 M M
11500 -0.8 30.6 230 27 14 3.5 1.9 19.5 67.2 5.6 M M
11000 0.2 32.4 225 27 14 8.5 4.7 19.1 66.5 5.3 M M
10500 0.5 32.9 235 28 14 -3.4 -1.9 17.9 64.3 4.1 M M
10250 0.5 32.9 240 25 13 3.5 1.9 17.2 62.9 3.4 M M
10000 0.7 33.3 240 21 11 -1.3 -0.7 16.6 62.0 2.9 M M
9750 0.5 32.9 235 20 10 -0.6 -0.3 15.6 60.0 1.9 M M
9500 0.8 33.4 230 16 8 7.5 4.1 15.2 59.4 1.6 M M
9250 1.4 34.5 220 14 7 7.3 4.0 15.0 59.0 1.4 M M
9000 1.9 35.4 195 16 8 7.1 3.9 14.8 58.7 1.2 M M
8750 2.5 36.5 190 17 9 8.3 4.6 14.6 58.3 1.0 M M
8500 3.0 37.4 185 19 10 3.6 2.0 14.4 58.0 0.8 M M
8250 3.1 37.6 185 20 10 1.0 0.6 13.7 56.7 0.2 M M
8000 3.3 37.9 180 22 11 5.9 3.2 13.3 55.9 -0.3 210 1.1
7750 3.9 39.0 175 21 11 9.4 5.1 13.1 55.6 -0.5 187 1.0
7500 4.4 39.9 175 21 11 1.2 0.7 12.9 55.2 -0.7 164 0.8
7250 3.9 39.0 170 22 11 -8.9 -4.9 11.7 53.1 -1.9 171 0.9
7000 3.4 38.1 170 20 10 -0.2 -0.1 10.5 50.9 -3.2 179 0.9
6750 3.5 38.3 170 19 10 0.0 0.0 10.0 50.0 -3.8 167 0.8
6500 3.1 37.6 165 16 8 -10.3 -5.7 8.8 47.8 -5.0 174 0.9
6250 2.3 36.1 155 13 7 -9.6 -5.3 7.2 45.0 -6.5 190 1.0
6000 1.9 35.4 145 11 5 -0.6 -0.3 6.0 42.9 -7.7 195 1.0
5750 2.1 35.8 135 10 5 4.3 2.3 5.5 42.0 -8.2 182 0.9
5500 2.3 36.1 130 10 5 1.7 1.0 5.0 41.0 -8.8 168 0.9
5250 2.3 36.1 120 10 5 -2.0 -1.1 4.3 39.7 -9.5 162 0.8
5000 1.9 35.4 130 12 6 -9.3 -5.1 3.2 37.7 -10.7 166 0.8
* * * * * * Numerical weather prediction model forecast data valid * * * * * *
11/14/2024 at 0800 MST | 11/14/2024 at 1100 MST
|
CAPE... 0.0 LI... +9.3 | CAPE... 0.0 LI... +9.1
CINH... -0.0 K Index... -15.1 | CINH... 0.0 K Index... -15.5
|
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 -64.4 -83.9 255 66 34 1.4 0.8 | -64.5 -84.1 245 68 35 1.4 0.8
45000 -62.0 -79.6 255 85 44 3.4 1.8 | -62.1 -79.8 245 85 44 3.5 1.9
40000 -56.6 -69.9 250 87 45 3.3 1.8 | -56.6 -69.9 250 88 45 3.7 2.0
38000 -53.5 -64.3 250 86 44 5.4 2.9 | -53.5 -64.3 245 88 45 5.0 2.8
36000 -50.3 -58.5 250 86 44 5.4 2.9 | -50.4 -58.7 245 87 45 5.0 2.8
34000 -46.5 -51.7 250 85 44 7.5 4.1 | -46.7 -52.1 245 86 44 7.4 4.0
32000 -42.0 -43.6 250 85 44 7.5 4.1 | -42.3 -44.1 245 83 43 7.4 4.0
30000 -37.5 -35.5 250 84 43 7.3 4.0 | -37.9 -36.2 245 81 42 7.4 4.0
29000 -35.3 -31.5 250 83 43 7.3 4.0 | -35.7 -32.3 245 80 41 7.4 4.0
28000 -33.2 -27.8 255 81 42 7.3 4.0 | -33.5 -28.3 245 79 41 7.4 4.0
27000 -31.0 -23.8 255 80 41 6.7 3.7 | -31.3 -24.3 245 77 40 7.0 3.8
26000 -29.0 -20.2 255 77 39 6.7 3.7 | -29.2 -20.6 250 75 38 7.0 3.8
25000 -27.0 -16.6 255 74 38 6.7 3.7 | -27.1 -16.8 250 72 37 7.0 3.8
24000 -24.4 -11.9 255 70 36 7.4 4.0 | -25.0 -13.0 250 69 36 7.3 4.0
23000 -22.2 -8.0 255 67 35 7.3 4.0 | -22.2 -8.0 250 66 34 7.4 4.1
22000 -20.0 -4.0 255 64 33 7.3 4.0 | -20.0 -4.0 250 63 32 7.4 4.1
21000 -17.8 -0.0 250 62 32 7.6 4.2 | -17.8 -0.0 250 61 31 7.6 4.2
20000 -15.5 4.1 250 59 30 7.7 4.2 | -15.5 4.1 250 58 30 7.6 4.2
19500 -14.3 6.3 250 58 30 7.6 4.2 | -14.3 6.3 250 57 29 7.6 4.2
19000 -13.2 8.2 250 57 29 7.5 4.1 | -13.2 8.2 250 56 29 7.6 4.1
18500 -12.1 10.2 250 56 29 7.1 3.9 | -12.1 10.2 250 55 28 7.1 3.9
18000 -11.0 12.2 250 54 28 7.1 3.9 | -11.0 12.2 250 54 28 7.1 3.9
17500 -10.0 14.0 250 52 27 6.7 3.7 | -10.0 14.0 250 52 27 6.8 3.7
17000 -9.0 15.8 250 51 26 6.7 3.7 | -9.0 15.8 250 51 26 6.7 3.7
16500 -8.0 17.6 250 49 25 6.5 3.6 | -8.0 17.6 250 49 25 6.4 3.5
16000 -7.1 19.2 250 47 24 6.1 3.4 | -7.1 19.2 245 48 24 5.8 3.2
15500 -6.1 21.0 250 46 23 6.1 3.4 | -6.2 20.8 245 46 24 5.9 3.2
15000 -5.3 22.5 250 44 23 5.6 3.1 | -5.4 22.3 245 44 23 5.4 2.9
14500 -4.4 24.1 250 42 22 5.7 3.1 | -4.6 23.7 245 42 22 5.4 3.0
14000 -3.6 25.5 250 40 21 5.2 2.9 | -3.8 25.2 245 40 21 5.1 2.8
13500 -2.8 27.0 250 38 20 5.2 2.9 | -3.0 26.6 245 38 20 5.1 2.8
13000 -2.1 28.2 245 36 19 4.4 2.4 | -2.3 27.9 245 36 19 4.9 2.7
12500 -1.4 29.5 245 34 17 4.2 2.3 | -1.6 29.1 245 34 17 4.8 2.6
12000 -0.9 30.4 245 32 16 3.4 1.9 | -0.9 30.4 245 32 16 4.1 2.2
11500 -0.4 31.3 240 30 15 3.0 1.6 | -0.3 31.5 240 29 15 3.7 2.0
11000 -0.0 32.0 240 27 14 2.6 1.4 | 0.2 32.4 235 27 14 3.1 1.7
10500 0.3 32.5 235 24 13 2.6 1.4 | 0.6 33.1 230 24 12 3.0 1.6
10250 0.5 32.9 230 23 12 1.6 0.9 | 0.8 33.4 230 22 12 1.8 1.0
10000 0.6 33.1 230 22 11 1.8 1.0 | 0.9 33.6 230 23 12 2.2 1.2
9750 0.7 33.3 230 21 11 3.1 1.7 | 1.1 34.0 225 21 11 3.8 2.1
9500 1.0 33.8 225 19 10 3.3 1.8 | 1.3 34.3 225 19 10 3.5 1.9
9250 1.2 34.2 220 17 9 2.5 1.3 | 1.6 34.9 220 17 9 3.3 1.8
9000 1.3 34.3 215 15 8 1.3 0.7 | 1.8 35.2 215 15 8 3.1 1.7
8750 1.4 34.5 210 14 7 2.5 1.4 | 2.1 35.8 210 14 7 3.8 2.1
8500 1.6 34.9 205 13 7 3.4 1.8 | 2.3 36.1 210 13 7 4.3 2.4
8250 2.1 35.8 195 12 6 3.1 1.7 | 2.6 36.7 205 12 6 3.4 1.9
8000 2.3 36.1 190 11 6 2.8 1.6 | 3.1 37.6 195 10 5 3.9 2.2
7750 2.5 36.5 185 11 5 2.7 1.5 | 3.4 38.1 190 8 4 4.6 2.5
7500 2.7 36.9 185 10 5 3.0 1.7 | 3.7 38.7 190 7 4 3.7 2.0
7250 2.9 37.2 180 10 5 3.2 1.7 | 3.9 39.0 180 6 3 1.9 1.0
7000 3.2 37.8 170 10 5 3.1 1.7 | 4.2 39.6 175 5 3 7.9 4.3
6750 3.3 37.9 170 7 4 1.2 0.6 | 5.0 41.0 175 4 2 10.7 5.9
6500 3.3 37.9 165 7 3 -0.5 -0.3 | 5.6 42.1 175 3 2 7.2 4.0
6250 3.3 37.9 160 6 3 0.7 0.4 | 6.1 43.0 175 3 1 6.8 3.7
6000 3.3 37.9 150 5 3 -2.5 -1.4 | 6.7 44.1 170 2 1 10.8 5.9
5750 2.7 36.9 120 3 1 -15.9 -8.7 | 7.9 46.2 180 2 1 21.2 11.6
5500 0.9 33.6 070 2 1 -31.9 -17.5 | 9.1 48.4 185 1 1 -0.1 -0.1
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
11/14/2024 at 1400 MST | 11/14/2024 at 1700 MST
|
CAPE... 0.0 LI... +8.3 | CAPE... 0.0 LI... +7.0
CINH... -0.2 K Index... -14.0 | CINH... -0.0 K Index... -13.9
|
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 -64.5 -84.1 245 69 35 1.0 0.5 | -64.9 -84.8 240 68 35 1.6 0.9
45000 -62.6 -80.7 245 88 45 4.0 2.2 | -62.2 -80.0 245 89 46 3.3 1.8
40000 -56.4 -69.5 245 90 47 4.1 2.3 | -57.2 -71.0 240 91 47 3.4 1.9
38000 -53.4 -64.1 245 91 47 4.6 2.5 | -54.2 -65.6 240 91 47 5.5 3.0
36000 -50.6 -59.1 240 92 47 4.6 2.5 | -50.5 -58.9 240 91 47 5.5 3.0
34000 -47.1 -52.8 240 90 47 7.5 4.1 | -46.7 -52.1 240 89 46 7.3 4.0
32000 -42.6 -44.7 245 87 45 7.5 4.1 | -42.3 -44.1 240 87 45 7.3 4.0
30000 -38.1 -36.6 245 83 43 7.5 4.1 | -37.9 -36.2 240 84 43 7.3 4.0
29000 -35.8 -32.4 245 82 42 7.5 4.1 | -35.7 -32.3 240 82 42 7.3 4.0
28000 -33.6 -28.5 245 80 41 7.5 4.1 | -33.5 -28.3 240 80 41 7.3 4.0
27000 -31.4 -24.5 245 78 40 7.2 3.9 | -31.4 -24.5 240 78 40 7.1 3.9
26000 -29.2 -20.6 245 75 39 7.2 4.0 | -29.2 -20.6 240 75 38 7.2 3.9
25000 -27.1 -16.8 245 72 37 7.2 4.0 | -27.1 -16.8 240 72 37 7.2 3.9
24000 -24.9 -12.8 245 69 35 7.4 4.1 | -24.9 -12.8 240 68 35 7.2 3.9
23000 -22.1 -7.8 245 65 33 7.4 4.1 | -22.8 -9.0 240 65 33 7.2 3.9
22000 -19.9 -3.8 245 61 32 7.4 4.1 | -20.1 -4.2 240 60 31 7.2 3.9
21000 -17.7 0.1 245 58 30 7.3 4.0 | -18.0 -0.4 235 57 29 6.9 3.8
20000 -15.5 4.1 245 56 29 7.3 4.0 | -15.9 3.4 235 53 27 6.9 3.8
19500 -14.4 6.1 245 55 28 7.3 4.0 | -14.9 5.2 235 51 26 6.9 3.8
19000 -13.3 8.1 245 54 28 7.2 4.0 | -13.8 7.2 235 50 26 6.9 3.8
18500 -12.3 9.9 245 53 27 7.0 3.8 | -12.8 9.0 235 48 25 7.0 3.8
18000 -11.2 11.8 245 51 26 7.0 3.9 | -11.8 10.8 235 47 24 7.0 3.8
17500 -10.2 13.6 245 50 26 6.6 3.6 | -10.7 12.7 235 45 23 6.7 3.7
17000 -9.2 15.4 245 49 25 6.5 3.6 | -9.8 14.4 240 44 23 6.5 3.6
16500 -8.2 17.2 245 48 25 6.4 3.5 | -8.8 16.2 240 43 22 6.6 3.6
16000 -7.3 18.9 245 46 24 6.2 3.4 | -7.8 18.0 240 42 21 6.7 3.7
15500 -6.4 20.5 245 45 23 6.3 3.5 | -6.8 19.8 240 41 21 6.7 3.7
15000 -5.5 22.1 245 43 22 5.6 3.1 | -5.8 21.6 240 39 20 6.6 3.6
14500 -4.6 23.7 245 41 21 5.7 3.1 | -4.8 23.4 240 38 20 6.6 3.6
14000 -3.8 25.2 245 39 20 5.3 2.9 | -3.8 25.2 235 37 19 6.5 3.6
13500 -3.0 26.6 240 37 19 5.2 2.9 | -2.9 26.8 235 35 18 6.5 3.6
13000 -2.3 27.9 240 35 18 5.3 2.9 | -1.9 28.6 235 33 17 6.3 3.5
12500 -1.5 29.3 240 33 17 5.4 2.9 | -1.0 30.2 230 31 16 6.2 3.4
12000 -0.7 30.7 235 31 16 5.2 2.8 | -0.1 31.8 230 30 15 6.1 3.3
11500 0.0 32.0 235 28 15 5.0 2.7 | 0.8 33.4 225 27 14 5.8 3.2
11000 0.8 33.4 230 26 13 4.2 2.3 | 1.7 35.1 220 25 13 5.5 3.0
10500 1.3 34.3 225 24 12 3.2 1.8 | 2.4 36.3 215 23 12 4.7 2.6
10250 1.5 34.7 225 23 12 5.2 2.9 | 2.8 37.0 215 22 11 6.3 3.4
10000 2.0 35.6 220 20 10 5.7 3.1 | 3.3 37.9 210 21 11 6.1 3.3
9750 2.3 36.1 215 19 10 4.0 2.2 | 3.6 38.5 205 19 10 4.3 2.4
9500 2.6 36.7 215 17 9 4.5 2.5 | 3.9 39.0 205 18 9 4.8 2.6
9250 2.9 37.2 210 16 8 4.2 2.3 | 4.3 39.7 200 17 9 4.8 2.6
9000 3.2 37.8 205 14 7 4.2 2.3 | 4.6 40.3 195 16 8 4.5 2.5
8750 3.5 38.3 200 12 6 4.5 2.5 | 4.9 40.8 190 14 7 4.2 2.3
8500 3.9 39.0 195 11 6 4.8 2.7 | 5.2 41.4 185 13 7 4.0 2.2
8250 4.2 39.6 190 10 5 4.1 2.2 | 5.9 42.6 175 11 6 5.7 3.1
8000 4.8 40.6 180 7 3 6.2 3.4 | 6.3 43.3 170 10 5 5.3 2.9
7750 5.3 41.5 180 5 3 7.8 4.3 | 6.7 44.1 165 8 4 4.6 2.5
7500 5.9 42.6 185 4 2 6.0 3.3 | 7.0 44.6 160 7 3 5.2 2.9
7250 6.2 43.2 190 3 1 4.1 2.3 | 7.4 45.3 160 6 3 5.9 3.2
7000 6.7 44.1 195 2 1 9.8 5.4 | 7.8 46.0 155 5 3 5.0 2.7
6750 7.6 45.7 210 2 1 12.3 6.8 | 8.2 46.8 145 3 1 4.6 2.5
6500 8.4 47.1 230 1 1 8.6 4.7 | 8.5 47.3 120 1 0 5.5 3.0
6250 9.0 48.2 270 1 1 7.9 4.3 | 9.0 48.2 340 1 0 5.5 3.0
6000 9.6 49.3 295 1 1 10.2 5.6 | 9.4 48.9 320 2 1 6.7 3.7
5750 10.6 51.1 265 1 1 17.2 9.4 | 9.7 49.5 340 2 1 -0.9 -0.5
5500 12.0 53.6 305 2 1 15.8 8.7 | 7.9 46.2 315 3 1 -60.6 -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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