Soaring Guidance
Issued by NWS Grand Junction, CO
Issued by NWS Grand Junction, CO
588
UXUS97 KGJT 091307
SRGGJT
Soaring Forecast
National Weather Service Grand Junction, Colorado
607 AM MST Saturday, November 9, 2024
This forecast is for Saturday, November 9, 2024:
If the trigger temperature of 47.6 F/8.7 C is reached...then
Thermal Soaring Index....................... Fair
Maximum rate of lift........................ 313 ft/min (1.6 m/s)
Maximum height of thermals.................. 9431 ft MSL (4592 ft AGL)
Forecast maximum temperature................... 49.0 F/9.9 C
Time of trigger temperature.................... 1245 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................. 7026 ft MSL (2187 ft AGL)
Thermal soaring outlook for Sunday 11/10....... Fair
Wave Soaring Index............................. Not available
Remarks...
Sunrise/Sunset.................... 06:51:31 / 17:04:27 MST
Total possible sunshine........... 10 hr 12 min 56 sec (612 min 56 sec)
Altitude of sun at 11:57:59 MST... 33.72 degrees
Upper air data from rawinsonde observation taken on 11/09/2024 at 0500 MST
Freezing level.................. 6919 ft MSL (2080 ft AGL)
Convective condensation level... 13063 ft MSL (8224 ft AGL)
Lifted condensation level....... 9943 ft MSL (5104 ft AGL)
Lifted index.................... +11.7
K index......................... +10.4
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 -65.6 -86.1 245 37 19 5.1 2.8 89.8 193.6 46.0 M M
45000 -56.1 -69.0 210 31 16 5.5 3.0 79.9 175.9 43.3 M M
40000 -47.9 -54.2 255 30 15 5.5 3.0 69.8 157.6 39.6 M M
38000 -44.7 -48.5 260 25 13 5.2 2.9 65.8 150.4 38.0 M M
36000 -41.6 -42.9 260 36 18 5.2 2.9 61.8 143.2 36.2 M M
34000 -39.8 -39.6 295 23 12 -8.6 -4.7 55.9 132.7 33.0 M M
32000 -43.5 -46.3 355 18 9 0.7 0.4 41.7 107.0 23.5 M M
30000 -40.4 -40.7 035 37 19 3.9 2.1 38.0 100.4 21.3 M M
29000 -38.6 -37.5 025 39 20 9.7 5.3 36.5 97.7 20.5 M M
28000 -35.8 -32.4 030 39 20 8.3 4.5 36.4 97.5 20.6 M M
27000 -33.5 -28.3 015 27 14 7.6 4.2 35.5 96.0 20.2 M M
26000 -31.2 -24.2 005 29 15 7.9 4.4 34.8 94.7 19.9 M M
25000 -28.8 -19.8 360 26 13 7.9 4.4 34.1 93.4 19.5 M M
24000 -26.4 -15.5 360 24 12 8.0 4.4 33.4 92.1 19.2 M M
23000 -24.0 -11.2 360 26 13 8.6 4.7 32.8 91.1 18.9 M M
22000 -21.4 -6.5 005 27 14 8.8 4.8 32.4 90.4 18.8 M M
21000 -19.4 -2.9 020 25 13 7.9 4.3 31.4 88.5 18.1 M M
20000 -17.5 0.5 005 32 16 5.7 3.1 30.1 86.2 17.2 M M
19500 -16.7 1.9 360 35 18 5.9 3.2 29.4 84.9 16.7 M M
19000 -15.8 3.6 005 34 18 6.6 3.6 28.8 83.8 16.2 M M
18500 -14.8 5.4 360 34 18 6.1 3.4 28.2 82.8 15.8 M M
18000 -13.6 7.5 360 32 16 5.3 2.9 27.1 80.8 15.0 M M
17500 -12.8 9.0 360 31 16 6.7 3.7 26.4 79.5 14.4 M M
17000 -11.7 10.9 360 29 15 5.7 3.1 26.1 78.9 14.2 M M
16500 -11.3 11.7 005 28 14 2.4 1.3 24.8 76.7 13.2 M M
16000 -10.7 12.7 355 28 14 4.5 2.5 23.9 74.9 12.4 M M
15500 -10.0 14.0 355 28 14 4.4 2.4 23.0 73.3 11.6 M M
15000 -9.4 15.1 350 25 13 4.5 2.4 22.1 71.7 10.9 M M
14500 -8.8 16.2 355 25 13 4.1 2.3 21.2 70.1 10.1 M M
14000 -8.2 17.2 005 23 12 4.4 2.4 20.2 68.4 9.3 M M
13500 -7.8 18.0 360 22 11 1.6 0.9 19.1 66.3 8.3 M M
13000 -7.1 19.2 355 23 12 5.9 3.2 18.2 64.7 7.5 M M
12500 -6.3 20.7 350 22 11 5.8 3.2 17.5 63.5 6.9 M M
12000 -5.7 21.7 360 21 11 2.5 1.4 16.7 62.0 6.1 M M
11500 -5.5 22.1 360 22 11 1.0 0.6 15.3 59.6 4.9 M M
11000 -5.3 22.5 005 24 12 0.4 0.2 13.9 57.0 3.6 M M
10500 -5.2 22.6 005 25 13 0.9 0.5 12.4 54.4 2.3 M M
10250 -5.1 22.8 360 26 13 3.2 1.8 11.8 53.2 1.7 M M
10000 -4.7 23.5 360 26 13 7.2 4.0 11.4 52.6 1.3 M M
9750 -4.3 24.3 005 24 13 0.2 0.1 11.1 52.0 1.0 M M
9500 -4.5 23.9 005 22 11 0.3 0.2 10.1 50.2 0.1 M M
9250 -4.1 24.6 010 19 10 6.8 3.7 9.8 49.6 -0.2 301 1.5
9000 -3.7 25.3 360 15 8 5.7 3.1 9.5 49.0 -0.5 280 1.4
8750 -3.2 26.2 360 14 7 6.0 3.3 9.2 48.5 -0.8 260 1.3
8500 -2.8 27.0 360 12 6 5.9 3.3 8.9 48.0 -1.1 239 1.2
8250 -2.3 27.9 005 9 5 6.0 3.3 8.6 47.4 -1.4 219 1.1
8000 -1.9 28.6 335 5 2 6.0 3.3 8.3 46.9 -1.7 198 1.0
7750 -1.5 29.3 325 5 3 5.9 3.2 8.0 46.4 -2.0 178 0.9
7500 -1.0 30.2 305 7 4 5.6 3.1 7.7 45.8 -2.3 158 0.8
7250 -0.6 30.9 295 10 5 5.6 3.1 7.3 45.2 -2.6 138 0.7
7000 -0.2 31.6 285 12 6 5.3 2.9 7.0 44.7 -3.0 118 0.6
6750 0.2 32.4 285 12 6 6.5 3.6 6.7 44.1 -3.3 99 0.5
6500 0.6 33.1 285 11 6 2.2 1.2 6.4 43.5 -3.6 79 0.4
6250 0.6 33.1 305 5 3 3.1 1.7 5.7 42.2 -4.3 71 0.4
6000 1.1 34.0 345 4 2 8.3 4.5 5.5 41.9 -4.6 48 0.2
5750 1.6 34.9 015 4 2 6.6 3.6 5.3 41.5 -4.8 25 0.1
5500 2.0 35.6 040 4 2 1.8 1.0 4.9 40.9 -5.2 7 0.0
5250 1.9 35.4 095 3 2 -2.4 -1.3 4.1 39.4 -6.0 2 0.0
5000 2.0 35.6 140 4 2 6.2 3.4 3.4 38.2 -6.7 M M
* * * * * * Numerical weather prediction model forecast data valid * * * * * *
11/09/2024 at 0800 MST | 11/09/2024 at 1100 MST
|
CAPE... +0.4 LI... +5.0 | CAPE... 0.0 LI... +6.1
CINH... -0.1 K Index... +12.5 | CINH... -0.2 K Index... +7.6
|
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 -60.9 -77.6 220 29 15 2.4 1.3 | -60.3 -76.5 240 27 14 2.7 1.5
45000 -56.6 -69.9 230 27 14 5.9 3.2 | -55.9 -68.6 245 27 14 4.4 2.4
40000 -47.7 -53.9 235 29 15 5.9 3.2 | -49.3 -56.7 245 27 14 4.4 2.4
38000 -45.9 -50.6 245 22 12 1.9 1.0 | -48.4 -55.1 260 22 11 0.2 0.1
36000 -44.6 -48.3 280 17 9 1.9 1.0 | -48.3 -54.9 290 16 8 0.2 0.1
34000 -43.6 -46.5 325 17 9 1.3 0.7 | -47.1 -52.8 325 17 9 5.0 2.8
32000 -42.9 -45.2 005 23 12 1.3 0.7 | -44.1 -47.4 345 19 10 5.0 2.7
30000 -40.7 -41.3 015 31 16 8.6 4.7 | -40.4 -40.7 350 24 12 8.6 4.7
29000 -38.1 -36.6 010 32 17 8.7 4.8 | -37.8 -36.0 350 26 14 8.6 4.7
28000 -35.5 -31.9 005 34 17 8.7 4.8 | -35.2 -31.4 350 29 15 8.7 4.7
27000 -32.9 -27.2 360 36 18 8.1 4.4 | -32.7 -26.9 350 31 16 8.0 4.4
26000 -30.6 -23.1 360 36 18 7.8 4.3 | -30.4 -22.7 350 32 17 7.9 4.3
25000 -28.3 -18.9 360 36 19 7.8 4.3 | -28.0 -18.4 350 33 17 7.9 4.3
24000 -26.0 -14.8 355 36 19 7.6 4.2 | -25.7 -14.3 350 34 18 7.4 4.1
23000 -23.9 -11.0 360 37 19 6.7 3.7 | -23.7 -10.7 350 35 18 6.6 3.6
22000 -21.5 -6.7 360 37 19 6.7 3.7 | -21.3 -6.3 355 35 18 6.6 3.6
21000 -19.6 -3.3 360 37 19 5.8 3.2 | -19.4 -2.9 355 36 19 6.2 3.4
20000 -17.8 -0.0 005 38 20 5.9 3.2 | -17.5 0.5 355 38 20 6.2 3.4
19500 -16.9 1.6 005 39 20 5.9 3.2 | -16.6 2.1 355 39 20 6.2 3.4
19000 -16.1 3.0 005 40 20 5.9 3.3 | -15.7 3.7 355 40 21 6.2 3.4
18500 -15.2 4.6 005 40 21 5.6 3.1 | -14.7 5.5 355 40 21 6.8 3.7
18000 -14.4 6.1 005 41 21 5.5 3.0 | -13.7 7.3 355 40 21 6.8 3.7
17500 -13.6 7.5 005 42 22 5.6 3.1 | -12.7 9.1 355 40 20 6.7 3.7
17000 -12.8 9.0 005 43 22 5.8 3.2 | -11.7 10.9 355 38 20 6.6 3.6
16500 -11.9 10.6 005 43 22 5.7 3.1 | -10.7 12.7 355 37 19 6.7 3.7
16000 -11.1 12.0 005 43 22 6.2 3.4 | -9.8 14.4 355 36 18 6.2 3.4
15500 -10.1 13.8 005 42 22 6.2 3.4 | -8.9 16.0 355 35 18 6.3 3.5
15000 -9.2 15.4 360 41 21 6.0 3.3 | -8.0 17.6 355 34 17 5.4 3.0
14500 -8.4 16.9 360 40 20 5.8 3.2 | -7.2 19.0 355 33 17 5.1 2.8
14000 -7.5 18.5 355 38 20 5.6 3.1 | -6.5 20.3 355 32 17 5.2 2.9
13500 -6.8 19.8 355 37 19 5.3 2.9 | -5.7 21.7 350 31 16 5.3 2.9
13000 -6.0 21.2 350 35 18 4.9 2.7 | -4.9 23.2 350 29 15 5.3 2.9
12500 -5.4 22.3 350 34 17 3.7 2.0 | -4.1 24.6 345 27 14 5.4 3.0
12000 -4.8 23.4 345 32 16 3.7 2.1 | -3.3 26.1 335 26 13 5.0 2.7
11500 -4.3 24.3 345 30 15 3.8 2.1 | -2.7 27.1 330 24 12 3.2 1.8
11000 -3.7 25.3 340 27 14 3.4 1.9 | -2.2 28.0 325 22 11 3.0 1.6
10500 -3.4 25.9 340 25 13 1.7 0.9 | -1.9 28.6 320 20 10 1.9 1.0
10250 -3.2 26.2 335 24 12 1.7 0.9 | -1.8 28.8 315 19 10 2.4 1.3
10000 -3.1 26.4 335 22 12 2.0 1.1 | -1.6 29.1 315 18 9 0.8 0.5
9750 -2.9 26.8 330 19 10 1.5 0.8 | -1.6 29.1 310 16 8 -0.3 -0.2
9500 -2.9 26.8 330 17 9 0.7 0.4 | -1.6 29.1 305 14 7 0.6 0.3
9250 -2.8 27.0 325 15 8 0.9 0.5 | -1.6 29.1 300 13 7 -0.2 -0.1
9000 -2.8 27.0 320 13 7 1.0 0.6 | -1.6 29.1 290 11 6 2.1 1.2
8750 -2.6 27.3 315 12 6 1.9 1.1 | -1.4 29.5 285 11 6 2.9 1.6
8500 -2.5 27.5 305 10 5 2.2 1.2 | -1.3 29.7 280 10 5 1.2 0.7
8250 -2.3 27.9 300 9 5 2.5 1.4 | -1.1 30.0 275 8 4 1.9 1.0
8000 -1.7 28.9 285 8 4 5.0 2.7 | -0.8 30.6 265 7 4 4.6 2.5
7750 -1.4 29.5 280 7 4 4.3 2.3 | -0.4 31.3 260 5 3 6.3 3.4
7500 -1.1 30.0 270 6 3 4.5 2.5 | 0.1 32.2 250 4 2 4.8 2.6
7250 -0.8 30.6 270 5 3 3.8 2.1 | 0.3 32.5 250 2 1 1.2 0.7
7000 -0.5 31.1 275 5 2 5.7 3.1 | 0.5 32.9 260 1 1 8.3 4.5
6750 0.0 32.0 265 3 2 6.9 3.8 | 1.4 34.5 230 1 1 13.7 7.5
6500 0.5 32.9 255 2 1 5.0 2.7 | 2.2 36.0 210 1 0 9.1 5.0
6250 0.8 33.4 000 0 0 3.9 2.2 | 2.8 37.0 000 0 0 7.9 4.4
6000 1.1 34.0 090 1 1 6.1 3.3 | 3.5 38.3 085 1 0 9.8 5.4
5750 1.7 35.1 130 1 1 9.9 5.4 | 4.4 39.9 195 1 0 15.9 8.7
5500 2.1 35.8 110 2 1 -2.7 -1.5 | 5.8 42.4 085 1 0 22.1 12.1
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
11/09/2024 at 1400 MST | 11/09/2024 at 1700 MST
|
CAPE... 0.0 LI... +6.8 | CAPE... 0.0 LI... +6.9
CINH... -0.0 K Index... +1.1 | CINH... 0.0 K Index... -2.1
|
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 -60.7 -77.3 260 34 18 3.5 1.9 | -60.6 -77.1 260 42 22 4.1 2.2
45000 -55.2 -67.4 255 37 19 3.1 1.7 | -54.6 -66.3 260 49 25 2.0 1.1
40000 -50.6 -59.1 260 33 17 3.0 1.6 | -51.6 -60.9 265 40 21 2.0 1.1
38000 -50.2 -58.4 265 28 15 -0.2 -0.1 | -50.9 -59.6 270 35 18 1.0 0.5
36000 -50.3 -58.5 275 22 11 -0.2 -0.1 | -50.3 -58.5 280 29 15 1.0 0.5
34000 -48.8 -55.8 290 18 9 6.8 3.7 | -48.5 -55.3 285 26 13 5.8 3.2
32000 -44.8 -48.6 300 17 9 6.7 3.7 | -45.0 -49.0 285 25 13 5.8 3.2
30000 -40.3 -40.5 310 19 10 8.8 4.8 | -40.8 -41.4 285 24 13 8.9 4.9
29000 -37.7 -35.9 315 22 11 8.7 4.8 | -38.2 -36.8 290 23 12 8.8 4.8
28000 -35.1 -31.2 320 25 13 8.8 4.8 | -35.5 -31.9 295 23 12 8.8 4.8
27000 -32.5 -26.5 320 28 14 7.9 4.4 | -33.0 -27.4 300 23 12 7.7 4.2
26000 -30.2 -22.4 325 28 15 7.9 4.4 | -30.6 -23.1 305 25 13 7.8 4.3
25000 -27.8 -18.0 335 29 15 7.9 4.4 | -28.3 -18.9 305 27 14 7.8 4.3
24000 -25.4 -13.7 340 30 16 7.3 4.0 | -26.0 -14.8 310 29 15 7.3 4.0
23000 -23.4 -10.1 340 31 16 6.8 3.7 | -23.9 -11.0 310 29 15 7.0 3.9
22000 -21.4 -6.5 340 32 17 6.8 3.7 | -21.3 -6.3 315 30 15 7.1 3.9
21000 -18.9 -2.0 340 33 17 6.9 3.8 | -19.1 -2.4 315 29 15 7.5 4.1
20000 -16.8 1.8 340 33 17 6.9 3.8 | -16.9 1.6 320 28 15 7.5 4.1
19500 -15.8 3.6 345 33 17 6.9 3.8 | -15.8 3.6 320 28 14 7.6 4.1
19000 -14.8 5.4 345 33 17 6.8 3.7 | -14.6 5.7 325 28 14 7.6 4.1
18500 -13.7 7.3 345 33 17 7.7 4.2 | -13.5 7.7 325 27 14 7.7 4.2
18000 -12.6 9.3 345 32 17 7.6 4.2 | -12.4 9.7 325 27 14 7.7 4.2
17500 -11.4 11.5 345 32 16 7.0 3.8 | -11.2 11.8 325 27 14 7.2 3.9
17000 -10.5 13.1 345 31 16 6.3 3.4 | -10.2 13.6 325 26 14 6.8 3.7
16500 -9.6 14.7 345 30 15 6.2 3.4 | -9.2 15.4 325 26 13 6.7 3.7
16000 -8.7 16.3 345 29 15 5.1 2.8 | -8.3 17.1 325 25 13 5.4 3.0
15500 -8.0 17.6 345 27 14 5.2 2.9 | -7.5 18.5 320 25 13 5.5 3.0
15000 -7.2 19.0 345 26 13 5.2 2.9 | -6.7 19.9 325 24 12 5.7 3.1
14500 -6.5 20.3 340 25 13 5.2 2.9 | -5.8 21.6 325 23 12 5.7 3.1
14000 -5.7 21.7 340 23 12 5.6 3.1 | -5.0 23.0 325 22 11 5.6 3.1
13500 -4.8 23.4 335 22 12 5.8 3.2 | -4.2 24.4 325 21 11 5.5 3.0
13000 -4.0 24.8 330 21 11 5.5 3.0 | -3.3 26.1 330 20 10 5.4 2.9
12500 -3.2 26.2 330 21 11 4.9 2.7 | -2.6 27.3 330 19 10 5.1 2.8
12000 -2.5 27.5 325 20 10 4.6 2.5 | -1.8 28.8 330 17 9 5.0 2.7
11500 -1.9 28.6 320 18 9 3.9 2.1 | -1.2 29.8 325 16 8 4.6 2.6
11000 -1.3 29.7 315 17 9 3.7 2.0 | -0.5 31.1 320 14 7 4.2 2.3
10500 -0.8 30.6 310 15 8 3.1 1.7 | 0.0 32.0 315 12 6 3.4 1.8
10250 -0.6 30.9 305 14 7 3.2 1.8 | 0.3 32.5 310 11 6 3.4 1.8
10000 -0.4 31.3 300 13 7 1.7 0.9 | 0.5 32.9 300 10 5 2.6 1.4
9750 -0.4 31.3 295 11 6 1.0 0.5 | 0.6 33.1 295 9 5 2.1 1.2
9500 -0.3 31.5 290 10 5 1.7 0.9 | 0.8 33.4 285 8 4 2.2 1.2
9250 -0.2 31.6 285 9 5 1.2 0.7 | 0.9 33.6 275 8 4 2.5 1.4
9000 -0.1 31.8 275 9 4 3.5 1.9 | 1.2 34.2 265 7 4 5.4 2.9
8750 0.3 32.5 270 8 4 4.1 2.3 | 1.6 34.9 260 7 4 5.2 2.8
8500 0.4 32.7 265 7 4 2.6 1.4 | 1.8 35.2 255 7 4 3.2 1.8
8250 0.6 33.1 255 6 3 3.2 1.8 | 2.4 36.3 240 6 3 4.6 2.5
8000 1.3 34.3 245 5 2 6.6 3.6 | 2.7 36.9 240 5 3 5.0 2.7
7750 1.8 35.2 240 4 2 8.1 4.5 | 3.1 37.6 230 4 2 4.8 2.7
7500 2.4 36.3 225 3 1 6.7 3.7 | 3.4 38.1 215 3 2 5.5 3.0
7250 2.8 37.0 215 2 1 4.2 2.3 | 3.9 39.0 200 3 1 5.9 3.3
7000 3.2 37.8 200 1 1 9.6 5.3 | 4.3 39.7 180 2 1 7.2 4.0
6750 4.1 39.4 200 2 1 13.3 7.3 | 4.9 40.8 160 2 1 8.5 4.7
6500 5.0 41.0 195 2 1 9.3 5.1 | 5.5 41.9 145 3 1 8.0 4.4
6250 5.6 42.1 180 1 1 8.2 4.5 | 6.1 43.0 135 3 1 8.2 4.5
6000 6.2 43.2 160 1 1 9.5 5.2 | 6.7 44.1 125 3 2 7.7 4.2
5750 7.1 44.8 195 1 1 15.0 8.2 | 7.1 44.8 125 2 1 1.6 0.9
5500 8.6 47.5 155 1 1 27.4 15.0 | 6.5 43.7 115 3 1 -22.8 -12.5
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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