Soaring Guidance
Issued by NWS Grand Junction, CO
Issued by NWS Grand Junction, CO
302
UXUS97 KGJT 011307
SRGGJT
Soaring Forecast
National Weather Service Grand Junction, Colorado
707 AM MDT Wednesday, May 1, 2024
This forecast is for Wednesday, May 1, 2024:
If the trigger temperature of 68.1 F/20.0 C is reached...then
Thermal Soaring Index....................... Poor
Maximum rate of lift........................ 21 ft/min (0.1 m/s)
Maximum height of thermals.................. 10283 ft MSL (5444 ft AGL)
Forecast maximum temperature................... 69.0 F/21.0 C
Time of trigger temperature.................... 1045 MDT
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................. 5483 ft MSL (644 ft AGL)
Thermal soaring outlook for Thursday 05/02..... Good
Wave Soaring Index............................. Not available
Remarks...
Sunrise/Sunset.................... 06:14:47 / 20:07:30 MDT
Total possible sunshine........... 13 hr 52 min 43 sec (832 min 43 sec)
Altitude of sun at 13:11:09 MDT... 66.16 degrees
Upper air data from rawinsonde observation taken on 05/01/2024 at 0600 MDT
Freezing level.................. 11926 ft MSL (7087 ft AGL)
Convective condensation level... 16610 ft MSL (11771 ft AGL)
Lifted condensation level....... 15917 ft MSL (11078 ft AGL)
Lifted index.................... +3.0
K index......................... +13.3
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 -57.3 -71.1 260 46 24 0.6 0.3 104.0 219.1 47.7 M M
45000 -52.8 -63.0 255 63 32 1.9 1.0 86.8 188.2 40.5 M M
40000 -57.1 -70.8 255 86 44 -5.6 -3.1 56.9 134.4 23.8 M M
38000 -58.8 -73.8 255 81 42 5.1 2.8 45.6 114.1 16.9 M M
36000 -54.7 -66.5 245 74 38 6.4 3.5 42.0 107.6 14.9 M M
34000 -50.3 -58.5 245 73 38 8.4 4.6 39.8 103.6 13.7 M M
32000 -45.3 -49.5 245 71 37 7.9 4.3 38.5 101.4 13.1 M M
30000 -40.9 -41.6 240 69 36 8.2 4.5 36.7 98.0 12.1 M M
29000 -38.4 -37.1 240 68 35 6.9 3.8 36.1 96.9 11.8 M M
28000 -36.7 -34.1 240 64 33 6.8 3.7 34.5 94.0 10.7 M M
27000 -34.7 -30.5 245 63 33 6.8 3.7 33.3 92.0 9.9 M M
26000 -32.6 -26.7 245 61 32 6.8 3.7 32.2 90.0 9.2 M M
25000 -30.6 -23.1 245 60 31 6.8 3.7 31.1 88.0 8.4 M M
24000 -28.5 -19.3 240 57 29 7.9 4.3 30.0 86.1 7.6 M M
23000 -25.9 -14.6 240 57 29 7.7 4.2 29.7 85.5 7.4 M M
22000 -24.0 -11.2 245 56 29 6.5 3.6 28.5 83.3 6.5 M M
21000 -22.1 -7.8 230 48 25 5.9 3.2 27.2 80.9 5.4 M M
20000 -20.4 -4.7 225 50 25 5.6 3.1 25.7 78.2 4.2 M M
19500 -19.0 -2.2 230 49 25 8.8 4.8 24.7 76.5 3.4 M M
19000 -17.9 -0.2 225 47 24 6.8 3.8 24.4 76.0 3.2 M M
18500 -16.9 1.6 225 43 22 7.0 3.8 23.9 75.1 2.7 M M
18000 -15.8 3.6 230 40 21 7.1 3.9 23.5 74.3 2.3 M M
17500 -14.8 5.4 225 39 20 7.7 4.2 23.0 73.4 1.9 M M
17000 -13.5 7.7 230 40 21 9.0 4.9 22.9 73.1 1.7 M M
16500 -12.2 10.0 230 36 18 8.9 4.9 22.8 73.0 1.7 M M
16000 -10.8 12.6 235 37 19 8.9 4.9 22.7 72.8 1.6 M M
15500 -9.5 14.9 235 38 20 8.9 4.9 22.5 72.6 1.5 M M
15000 -8.2 17.2 235 35 18 8.9 4.9 22.4 72.3 1.4 M M
14500 -6.8 19.8 240 32 16 8.9 4.9 22.3 72.1 1.3 M M
14000 -5.5 22.1 240 27 14 8.9 4.9 22.1 71.9 1.1 M M
13500 -4.1 24.6 245 27 14 8.9 4.9 22.0 71.6 1.0 M M
13000 -2.8 27.0 245 26 13 8.9 4.9 21.8 71.3 0.9 M M
12500 -1.5 29.3 245 23 12 9.0 4.9 21.7 71.0 0.7 M M
12000 -0.1 31.8 250 22 11 8.2 4.5 21.5 70.7 0.6 M M
11500 1.0 33.8 255 22 11 7.5 4.1 21.2 70.2 0.3 M M
11000 2.4 36.3 255 22 11 10.4 5.7 21.2 70.2 0.2 M M
10500 3.8 38.8 250 24 12 8.9 4.9 21.1 69.9 0.1 M M
10250 4.4 39.9 255 25 13 8.8 4.8 21.0 69.8 -0.0 418 2.1
10000 5.1 41.2 255 24 13 8.7 4.8 20.9 69.6 -0.1 391 2.0
9750 5.7 42.3 250 24 12 8.5 4.7 20.8 69.5 -0.2 365 1.9
9500 6.3 43.3 255 25 13 8.5 4.7 20.7 69.3 -0.2 338 1.7
9250 7.0 44.6 260 26 13 8.5 4.7 20.6 69.2 -0.3 312 1.6
9000 7.6 45.7 255 26 13 8.5 4.7 20.6 69.0 -0.4 285 1.5
8750 8.2 46.8 255 28 14 8.5 4.7 20.5 68.8 -0.5 259 1.3
8500 8.9 48.0 250 29 15 8.5 4.7 20.4 68.7 -0.6 233 1.2
8250 9.5 49.1 255 25 13 8.5 4.7 20.3 68.5 -0.7 206 1.0
8000 10.2 50.4 260 21 11 8.5 4.7 20.2 68.4 -0.8 180 0.9
7750 10.8 51.4 260 19 10 8.5 4.7 20.1 68.2 -0.9 153 0.8
7500 11.4 52.5 255 17 9 8.5 4.7 20.0 68.0 -1.0 127 0.6
7250 12.1 53.8 255 16 8 8.5 4.7 19.9 67.8 -1.1 100 0.5
7000 12.7 54.9 255 14 7 8.5 4.7 19.8 67.7 -1.2 74 0.4
6750 13.3 55.9 255 13 7 8.6 4.7 19.7 67.5 -1.3 47 0.2
6500 14.0 57.2 245 10 5 8.4 4.6 19.6 67.3 -1.4 21 0.1
6250 14.6 58.3 235 7 4 9.0 5.0 19.5 67.1 -1.5 M M
6000 15.2 59.4 195 6 3 6.2 3.4 19.4 66.9 -1.6 M M
5750 15.6 60.1 180 8 4 6.7 3.7 19.1 66.3 -2.0 M M
5500 15.9 60.6 155 10 5 -1.9 -1.0 18.7 65.7 -2.4 M M
5250 15.1 59.2 145 12 6 -15.4 -8.4 17.2 62.9 -4.0 M M
5000 14.1 57.4 135 13 7 -9.8 -5.4 15.4 59.7 -5.8 M M
* * * * * * Numerical weather prediction model forecast data valid * * * * * *
05/01/2024 at 0900 MDT | 05/01/2024 at 1200 MDT
|
CAPE... 0.0 LI... +0.1 | CAPE... +0.3 LI... +0.9
CINH... 0.0 K Index... +23.6 | CINH... -0.6 K Index... +21.8
|
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 -55.6 -68.1 250 42 22 1.8 1.0 | -55.2 -67.4 245 44 23 2.1 1.2
45000 -53.1 -63.6 250 56 29 -1.4 -0.8 | -52.2 -62.0 245 56 29 -1.3 -0.7
40000 -56.4 -69.5 250 81 42 -2.2 -1.2 | -55.6 -68.1 245 80 41 -2.3 -1.2
38000 -55.9 -68.6 250 85 44 4.1 2.2 | -55.3 -67.5 240 86 44 3.6 2.0
36000 -53.1 -63.6 245 83 43 4.1 2.3 | -52.9 -63.2 240 89 46 3.6 2.0
34000 -50.3 -58.5 245 80 41 6.8 3.8 | -50.3 -58.5 240 90 46 6.5 3.6
32000 -46.2 -51.2 240 77 40 6.9 3.8 | -46.5 -51.7 240 85 44 6.4 3.5
30000 -42.0 -43.6 240 73 38 7.1 3.9 | -42.5 -44.5 240 81 42 7.2 4.0
29000 -39.9 -39.8 240 71 37 7.1 3.9 | -40.4 -40.7 240 77 40 7.3 4.0
28000 -37.8 -36.0 240 69 36 7.1 3.9 | -38.2 -36.8 240 74 38 7.3 4.0
27000 -35.7 -32.3 240 68 35 7.0 3.8 | -36.0 -32.8 240 71 36 7.1 3.9
26000 -33.7 -28.7 240 65 33 6.5 3.6 | -34.0 -29.2 240 67 35 6.7 3.7
25000 -31.8 -25.2 240 62 32 6.5 3.6 | -32.0 -25.6 240 64 33 6.7 3.7
24000 -29.8 -21.6 240 58 30 6.5 3.5 | -30.0 -22.0 240 61 31 6.6 3.6
23000 -27.1 -16.8 240 56 29 7.3 4.0 | -27.4 -17.3 240 57 30 7.2 3.9
22000 -25.0 -13.0 240 54 28 7.3 4.0 | -25.3 -13.5 245 55 28 7.2 4.0
21000 -22.8 -9.0 240 51 26 7.1 3.9 | -23.1 -9.6 245 52 27 7.4 4.0
20000 -20.7 -5.3 240 47 24 7.2 3.9 | -21.0 -5.8 240 49 25 7.4 4.1
19500 -19.6 -3.3 240 46 23 7.2 3.9 | -19.9 -3.8 240 47 24 7.4 4.1
19000 -18.6 -1.5 240 44 22 7.2 4.0 | -18.8 -1.8 240 46 24 7.4 4.1
18500 -17.5 0.5 240 42 22 7.3 4.0 | -17.7 0.1 235 44 23 7.6 4.2
18000 -16.4 2.5 240 40 20 7.4 4.1 | -16.5 2.3 235 42 22 7.8 4.3
17500 -15.4 4.3 240 38 19 7.4 4.1 | -15.4 4.3 230 40 21 7.8 4.3
17000 -14.3 6.3 240 36 18 7.5 4.1 | -14.3 6.3 230 38 20 7.9 4.3
16500 -13.2 8.2 235 34 18 7.5 4.1 | -13.1 8.4 225 37 19 7.9 4.3
16000 -12.1 10.2 235 32 17 7.8 4.3 | -12.0 10.4 225 35 18 7.6 4.2
15500 -10.9 12.4 235 31 16 7.8 4.3 | -10.9 12.4 225 34 17 7.5 4.1
15000 -9.8 14.4 235 29 15 8.0 4.4 | -9.8 14.4 225 32 17 7.3 4.0
14500 -8.6 16.5 240 28 14 8.1 4.5 | -8.7 16.3 225 31 16 7.1 3.9
14000 -7.4 18.7 240 26 14 8.2 4.5 | -7.7 18.1 225 29 15 6.9 3.8
13500 -6.1 21.0 240 25 13 8.4 4.6 | -6.7 19.9 225 27 14 6.5 3.6
13000 -4.9 23.2 240 25 13 8.5 4.7 | -5.8 21.6 225 25 13 6.6 3.6
12500 -3.5 25.7 240 24 12 9.2 5.0 | -4.7 23.5 230 23 12 7.1 3.9
12000 -2.2 28.0 245 24 12 9.1 5.0 | -3.7 25.3 235 21 11 7.1 3.9
11500 -0.8 30.6 245 24 12 9.0 4.9 | -2.6 27.3 240 19 10 7.8 4.3
11000 0.5 32.9 245 23 12 8.9 4.9 | -1.4 29.5 245 16 8 7.7 4.2
10500 1.7 35.1 245 23 12 7.4 4.1 | -0.4 31.3 255 15 8 5.9 3.3
10250 2.3 36.1 250 23 12 8.9 4.9 | 0.1 32.2 255 14 7 7.0 3.8
10000 3.1 37.6 250 23 12 10.8 5.9 | 0.7 33.3 265 13 7 8.8 4.8
9750 3.9 39.0 250 22 11 9.1 5.0 | 1.3 34.3 270 13 7 8.4 4.6
9500 4.5 40.1 250 22 11 8.0 4.4 | 1.9 35.4 275 13 7 7.7 4.2
9250 5.1 41.2 250 22 11 8.2 4.5 | 2.5 36.5 275 13 6 7.7 4.2
9000 5.7 42.3 250 21 11 8.8 4.8 | 3.1 37.6 280 12 6 8.4 4.6
8750 6.4 43.5 245 19 10 8.6 4.7 | 3.7 38.7 285 13 7 9.4 5.2
8500 7.6 45.7 245 17 9 8.1 4.5 | 4.4 39.9 290 13 7 9.4 5.1
8250 8.2 46.8 245 16 8 7.5 4.1 | 5.8 42.4 295 13 7 9.7 5.3
8000 8.7 47.7 245 17 9 6.9 3.8 | 6.6 43.9 295 13 7 9.8 5.4
7750 9.2 48.6 245 15 8 7.1 3.9 | 7.3 45.1 295 13 7 9.6 5.3
7500 9.8 49.6 245 13 7 7.0 3.8 | 8.0 46.4 300 13 7 9.5 5.2
7250 10.3 50.5 245 12 6 6.0 3.3 | 8.7 47.7 300 13 7 8.5 4.7
7000 10.7 51.3 245 12 6 7.0 3.8 | 9.3 48.7 305 13 7 9.4 5.2
6750 11.3 52.3 240 10 5 8.4 4.6 | 10.1 50.2 305 13 7 10.5 5.8
6500 11.9 53.4 235 8 4 8.3 4.5 | 10.9 51.6 305 13 7 10.6 5.8
6250 12.6 54.7 235 8 4 9.3 5.1 | 11.7 53.1 305 13 7 12.3 6.7
6000 13.2 55.8 240 7 4 7.8 4.3 | 12.6 54.7 310 13 7 8.7 4.8
5750 13.8 56.8 235 6 3 9.0 4.9 | 13.1 55.6 305 12 6 10.5 5.7
5500 15.3 59.5 240 4 2 39.8 21.8 | 15.6 60.1 310 12 6 73.3 40.2
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
05/01/2024 at 1500 MDT | 05/01/2024 at 1800 MDT
|
CAPE... +1.1 LI... +1.1 | CAPE... +6.1 LI... +1.5
CINH... -11.9 K Index... +22.8 | CINH... -4.4 K Index... +20.6
|
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 -55.4 -67.7 245 46 24 2.4 1.3 | -54.2 -65.6 245 45 23 2.3 1.3
45000 -51.9 -61.4 245 57 29 -1.1 -0.6 | -50.8 -59.4 250 55 28 -1.2 -0.7
40000 -55.0 -67.0 245 79 41 -2.0 -1.1 | -54.9 -66.8 245 72 37 -2.7 -1.5
38000 -54.7 -66.5 245 86 44 3.3 1.8 | -55.1 -67.2 245 77 40 2.9 1.6
36000 -52.5 -62.5 240 92 47 3.3 1.8 | -53.2 -63.8 245 80 41 2.8 1.6
34000 -50.2 -58.4 240 95 49 6.0 3.3 | -51.1 -60.0 245 82 42 6.1 3.4
32000 -46.6 -51.9 240 90 47 6.0 3.3 | -47.6 -53.7 245 78 40 5.9 3.3
30000 -43.0 -45.4 240 85 44 6.5 3.6 | -43.9 -47.0 245 74 38 7.3 4.0
29000 -41.0 -41.8 240 80 41 6.5 3.6 | -41.7 -43.1 245 72 37 7.3 4.0
28000 -39.0 -38.2 240 75 38 6.6 3.6 | -39.5 -39.1 250 70 36 7.3 4.0
27000 -37.1 -34.8 240 70 36 6.8 3.7 | -37.3 -35.1 250 67 35 7.3 4.0
26000 -34.8 -30.6 240 65 34 7.7 4.2 | -35.2 -31.4 250 65 34 7.2 4.0
25000 -32.5 -26.5 240 61 32 7.7 4.2 | -33.0 -27.4 245 63 32 7.2 4.0
24000 -30.2 -22.4 245 57 29 7.8 4.3 | -30.9 -23.6 245 61 31 7.2 4.0
23000 -27.6 -17.7 245 53 27 6.9 3.8 | -28.7 -19.7 245 57 29 7.5 4.1
22000 -25.6 -14.1 240 50 26 6.9 3.8 | -25.9 -14.6 240 51 26 7.6 4.2
21000 -23.5 -10.3 240 47 24 8.0 4.4 | -23.6 -10.5 235 47 24 8.2 4.5
20000 -21.1 -6.0 240 47 24 8.1 4.5 | -21.2 -6.2 235 47 24 8.3 4.5
19500 -19.9 -3.8 240 46 24 8.1 4.5 | -20.0 -4.0 240 46 24 8.3 4.6
19000 -18.7 -1.7 240 46 24 8.2 4.5 | -18.8 -1.8 240 46 24 8.3 4.6
18500 -17.5 0.5 240 45 23 8.0 4.4 | -17.6 0.3 240 45 23 7.4 4.1
18000 -16.3 2.7 240 45 23 7.9 4.4 | -16.5 2.3 240 44 22 7.0 3.8
17500 -15.2 4.6 240 44 23 7.9 4.3 | -15.5 4.1 240 42 22 7.0 3.8
17000 -14.1 6.6 235 43 22 7.3 4.0 | -14.5 5.9 245 40 21 6.8 3.7
16500 -13.0 8.6 235 41 21 7.4 4.0 | -13.5 7.7 245 37 19 6.8 3.7
16000 -12.4 9.7 235 40 21 6.9 3.8 | -12.5 9.5 250 35 18 6.6 3.6
15500 -10.9 12.4 235 38 20 6.9 3.8 | -11.6 11.1 250 33 17 6.6 3.6
15000 -9.9 14.2 235 36 19 6.8 3.8 | -10.6 12.9 255 31 16 6.7 3.7
14500 -8.9 16.0 240 34 17 6.8 3.7 | -9.6 14.7 255 29 15 6.8 3.7
14000 -7.9 17.8 240 32 16 6.8 3.7 | -8.6 16.5 260 28 14 6.9 3.8
13500 -7.0 19.4 240 30 15 6.6 3.6 | -7.5 18.5 260 26 13 7.3 4.0
13000 -6.0 21.2 245 28 14 6.7 3.7 | -6.5 20.3 265 25 13 7.4 4.1
12500 -5.0 23.0 245 25 13 7.0 3.8 | -5.3 22.5 265 23 12 8.1 4.4
12000 -4.0 24.8 250 23 12 6.9 3.8 | -4.1 24.6 265 22 11 8.1 4.4
11500 -3.0 26.6 255 21 11 5.8 3.2 | -2.8 27.0 270 21 11 8.6 4.7
11000 -2.2 28.0 260 19 10 5.9 3.2 | -1.6 29.1 270 19 10 8.5 4.6
10500 -1.3 29.7 265 18 9 5.6 3.1 | -0.4 31.3 275 19 10 7.4 4.0
10250 -0.9 30.4 270 17 9 6.5 3.6 | 0.2 32.4 275 19 10 8.6 4.7
10000 -0.3 31.5 270 17 9 8.9 4.9 | 0.9 33.6 275 18 9 10.6 5.8
9750 0.4 32.7 275 16 8 8.3 4.6 | 1.7 35.1 275 16 8 9.6 5.3
9500 0.9 33.6 275 16 8 7.1 3.9 | 2.4 36.3 275 16 8 8.5 4.7
9250 1.4 34.5 280 16 8 7.2 3.9 | 3.0 37.4 275 16 8 8.8 4.8
9000 2.0 35.6 280 16 8 8.1 4.5 | 3.7 38.7 275 16 8 8.9 4.9
8750 2.6 36.7 280 16 8 8.6 4.7 | 4.3 39.7 275 13 7 8.6 4.7
8500 3.8 38.8 285 15 8 8.1 4.4 | 4.9 40.8 275 12 6 8.2 4.5
8250 4.4 39.9 285 15 8 7.7 4.3 | 6.1 43.0 275 10 5 8.6 4.7
8000 4.9 40.8 290 14 7 8.4 4.6 | 6.7 44.1 275 11 5 8.7 4.7
7750 5.6 42.1 290 13 7 9.3 5.1 | 7.4 45.3 275 9 5 8.3 4.6
7500 6.3 43.3 295 12 6 8.8 4.8 | 8.0 46.4 275 7 4 8.1 4.5
7250 6.9 44.4 300 12 6 7.6 4.2 | 8.5 47.3 275 6 3 6.3 3.5
7000 7.5 45.5 300 12 6 9.3 5.1 | 9.3 48.7 275 7 3 7.8 4.3
6750 8.3 46.9 300 11 6 11.3 6.2 | 9.6 49.3 275 5 3 9.7 5.3
6500 9.1 48.4 305 10 5 10.5 5.8 | 10.3 50.5 280 4 2 9.6 5.3
6250 9.9 49.8 305 10 5 11.3 6.2 | 11.1 52.0 275 4 2 11.1 6.1
6000 10.7 51.3 310 10 5 8.4 4.6 | 11.9 53.4 270 4 2 8.5 4.6
5750 11.3 52.3 305 10 5 12.5 6.9 | 12.4 54.3 275 3 2 8.2 4.5
5500 14.0 57.2 315 9 5 79.0 43.4 | 14.0 57.2 275 3 1 44.7 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
________________________________________________________________________________
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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