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Soaring Guidance
Issued by NWS Grand Junction, CO
Issued by NWS Grand Junction, CO
000
UXUS97 KGJT 231307
SRGGJT
Soaring Forecast
National Weather Service Grand Junction, Colorado
707 AM MDT Tuesday, April 23, 2024
This forecast is for Tuesday, April 23, 2024:
If the trigger temperature of 70.9 F/21.6 C is reached...then
Thermal Soaring Index....................... Excellent
Maximum rate of lift........................ 1738 ft/min (8.8 m/s)
Maximum height of thermals.................. 22956 ft MSL (18117 ft AGL)
Forecast maximum temperature................... 85.0 F/29.9 C
Time of trigger temperature.................... 1030 MDT
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................. 17985 ft MSL (13146 ft AGL)
Thermal soaring outlook for Wednesday 04/24.... Excellent
Wave Soaring Index............................. Not available
Remarks...
Sunrise/Sunset.................... 06:24:56 / 19:59:42 MDT
Total possible sunshine........... 13 hr 34 min 46 sec (814 min 46 sec)
Altitude of sun at 13:12:19 MDT... 63.63 degrees
Upper air data from rawinsonde observation taken on 04/23/2024 at 0600 MDT
Freezing level.................. 12432 ft MSL (7593 ft AGL)
Convective condensation level... 15275 ft MSL (10436 ft AGL)
Lifted condensation level....... 17570 ft MSL (12731 ft AGL)
Lifted index.................... -4.8
K index......................... +24.0
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 -57.0 -70.6 275 53 27 2.7 1.5 105.1 221.2 43.2 M M
45000 -57.5 -71.5 275 70 36 -11.1 -6.1 78.4 173.2 30.0 M M
40000 -60.4 -76.7 270 69 36 6.9 3.8 50.6 123.1 13.9 M M
38000 -57.0 -70.6 270 66 34 5.4 3.0 46.9 116.4 11.8 M M
36000 -53.1 -63.6 270 58 30 8.1 4.4 44.0 111.1 10.1 M M
34000 -48.4 -55.1 275 55 29 6.9 3.8 42.4 108.3 9.2 M M
32000 -43.5 -46.3 275 55 28 8.3 4.6 40.1 104.2 7.8 M M
30000 -38.4 -37.1 280 54 28 9.0 4.9 39.1 102.4 7.3 M M
29000 -35.8 -32.4 275 53 27 7.6 4.2 38.6 101.5 7.0 M M
28000 -33.3 -27.9 275 50 26 7.7 4.2 38.1 100.5 6.6 M M
27000 -31.6 -24.9 275 47 24 3.4 1.9 36.5 97.8 5.5 M M
26000 -30.4 -22.7 275 42 22 7.7 4.2 34.4 93.9 3.9 M M
25000 -28.1 -18.6 275 39 20 7.4 4.1 33.6 92.5 3.3 M M
24000 -25.7 -14.3 275 38 20 8.6 4.7 33.0 91.3 2.8 M M
23000 -25.4 -13.7 270 26 13 -2.3 -1.3 29.8 85.6 0.1 M M
22000 -23.2 -9.8 280 24 12 8.8 4.8 29.0 84.2 -0.5 1647 8.4
21000 -20.6 -5.1 280 28 14 8.8 4.8 28.6 83.5 -0.9 1539 7.8
20000 -18.0 -0.4 280 29 15 8.7 4.8 28.2 82.8 -1.2 1431 7.3
19500 -16.7 1.9 280 29 15 8.4 4.6 28.0 82.5 -1.4 1377 7.0
19000 -15.5 4.1 275 27 14 7.9 4.3 27.7 81.8 -1.7 1328 6.7
18500 -14.5 5.9 260 30 15 6.2 3.4 27.2 81.0 -2.2 1282 6.5
18000 -13.6 7.5 255 32 16 4.8 2.7 26.6 79.8 -2.8 1241 6.3
17500 -12.7 9.1 260 32 17 6.4 3.5 25.2 77.3 -4.1 1192 6.1
17000 -11.4 11.5 255 32 16 8.5 4.7 25.0 77.0 -4.3 1139 5.8
16500 -10.2 13.6 260 30 16 8.6 4.7 24.8 76.6 -4.5 1087 5.5
16000 -8.9 16.0 260 29 15 8.7 4.8 24.6 76.3 -4.7 1034 5.3
15500 -7.7 18.1 265 25 13 8.0 4.4 24.4 75.9 -5.0 982 5.0
15000 -6.5 20.3 265 26 13 8.0 4.4 24.1 75.4 -5.3 932 4.7
14500 -5.3 22.5 270 24 12 8.0 4.4 23.8 74.8 -5.6 882 4.5
14000 -4.1 24.6 285 22 11 8.9 4.9 23.6 74.4 -5.9 830 4.2
13500 -2.8 27.0 280 21 11 9.0 4.9 23.5 74.3 -6.0 776 3.9
13000 -1.4 29.5 275 20 10 9.0 4.9 23.4 74.1 -6.1 721 3.7
12500 -0.1 31.8 280 15 8 9.0 4.9 23.3 73.9 -6.3 666 3.4
12000 1.3 34.3 275 11 6 9.0 4.9 23.1 73.6 -6.4 611 3.1
11500 2.6 36.7 280 11 6 9.0 4.9 23.0 73.4 -6.6 556 2.8
11000 3.9 39.0 290 11 6 9.0 4.9 22.9 73.2 -6.7 501 2.5
10500 5.3 41.5 305 12 6 9.0 4.9 22.7 72.9 -6.9 446 2.3
10250 5.9 42.6 315 12 6 8.9 4.9 22.7 72.8 -7.0 419 2.1
10000 6.6 43.9 310 15 8 8.8 4.8 22.6 72.7 -7.1 392 2.0
9750 7.2 45.0 305 15 8 8.7 4.8 22.5 72.6 -7.2 365 1.9
9500 7.9 46.2 315 14 7 8.7 4.8 22.5 72.4 -7.3 338 1.7
9250 8.5 47.3 325 13 7 8.7 4.8 22.4 72.3 -7.4 312 1.6
9000 9.2 48.6 320 11 6 8.7 4.8 22.3 72.2 -7.5 285 1.4
8750 9.8 49.6 325 11 5 8.7 4.8 22.3 72.1 -7.6 258 1.3
8500 10.5 50.9 330 10 5 8.7 4.8 22.2 71.9 -7.6 231 1.2
8250 11.1 52.0 340 9 5 8.7 4.8 22.1 71.8 -7.8 204 1.0
8000 11.8 53.2 355 8 4 8.7 4.8 22.0 71.7 -7.8 178 0.9
7750 12.4 54.3 350 8 4 8.7 4.8 22.0 71.5 -7.9 151 0.8
7500 13.1 55.6 360 8 4 8.7 4.8 21.9 71.4 -8.1 124 0.6
7250 13.7 56.7 015 5 2 8.7 4.8 21.8 71.2 -8.2 97 0.5
7000 14.4 57.9 040 3 2 8.7 4.8 21.7 71.1 -8.3 71 0.4
6750 15.0 59.0 060 4 2 8.8 4.8 21.6 70.9 -8.4 44 0.2
6500 15.6 60.1 075 4 2 8.7 4.8 21.5 70.8 -8.5 17 0.1
6250 16.3 61.3 080 4 2 8.8 4.8 21.5 70.6 -8.6 M M
6000 16.9 62.4 080 4 2 8.7 4.8 21.4 70.5 -8.7 M M
5750 17.6 63.7 070 4 2 8.8 4.8 21.3 70.3 -8.8 M M
5500 18.0 64.4 055 5 2 0.9 0.5 21.0 69.8 -9.1 M M
5250 17.6 63.7 045 4 2 -11.7 -6.4 19.8 67.7 -10.4 M M
5000 16.5 61.7 055 1 1 -15.0 -8.2 18.0 64.4 -12.2 M M
* * * * * * Numerical weather prediction model forecast data valid * * * * * *
04/23/2024 at 0900 MDT | 04/23/2024 at 1200 MDT
|
CAPE... 0.0 LI... +0.2 | CAPE... +20.8 LI... +0.3
CINH... -0.1 K Index... +19.9 | CINH... -6.7 K Index... +19.1
|
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 -58.8 -73.8 285 60 31 0.4 0.2 | -58.7 -73.7 280 61 31 0.2 0.1
45000 -58.3 -72.9 275 62 32 -0.7 -0.4 | -58.4 -73.1 275 64 33 -0.6 -0.3
40000 -59.4 -74.9 270 63 32 -0.6 -0.3 | -59.3 -74.7 275 65 33 -0.4 -0.2
38000 -56.8 -70.2 270 60 31 6.0 3.3 | -56.6 -69.9 270 62 32 6.3 3.5
36000 -53.2 -63.8 270 57 29 6.0 3.3 | -52.4 -62.3 270 57 30 6.3 3.5
34000 -49.1 -56.4 270 54 28 8.1 4.4 | -48.2 -54.8 265 54 28 7.5 4.1
32000 -44.2 -47.6 270 52 27 8.1 4.4 | -43.8 -46.8 265 51 26 7.5 4.1
30000 -39.2 -38.6 270 49 25 8.7 4.7 | -39.0 -38.2 265 48 25 8.4 4.6
29000 -36.6 -33.9 270 47 24 8.7 4.7 | -36.5 -33.7 265 46 24 8.4 4.6
28000 -33.4 -28.1 270 45 23 8.6 4.7 | -34.0 -29.2 265 45 23 8.4 4.6
27000 -31.1 -24.0 270 43 22 6.4 3.5 | -31.6 -24.9 265 43 22 6.4 3.5
26000 -29.2 -20.6 275 41 21 6.4 3.5 | -29.7 -21.5 265 40 21 6.5 3.6
25000 -27.3 -17.1 275 38 20 6.4 3.5 | -27.7 -17.9 265 38 20 6.6 3.6
24000 -25.5 -13.9 275 36 19 5.9 3.3 | -25.8 -14.4 260 36 18 6.7 3.7
23000 -23.7 -10.7 270 35 18 6.0 3.3 | -23.8 -10.8 260 34 17 6.7 3.7
22000 -21.9 -7.4 270 33 17 6.0 3.3 | -21.3 -6.3 260 31 16 6.7 3.7
21000 -20.0 -4.0 270 31 16 7.0 3.8 | -19.2 -2.6 260 29 15 7.1 3.9
20000 -17.9 -0.2 270 29 15 7.0 3.8 | -17.1 1.2 260 28 15 7.1 3.9
19500 -16.9 1.6 270 28 15 7.0 3.9 | -16.1 3.0 260 28 14 7.1 3.9
19000 -15.8 3.6 265 27 14 7.1 3.9 | -15.1 4.8 255 27 14 7.0 3.8
18500 -14.8 5.4 265 27 14 7.4 4.1 | -14.1 6.6 255 27 14 6.6 3.6
18000 -13.7 7.3 265 26 14 7.4 4.1 | -13.1 8.4 255 26 13 6.6 3.6
17500 -12.6 9.3 265 26 13 7.5 4.1 | -12.1 10.2 250 25 13 7.2 4.0
17000 -11.5 11.3 260 26 13 7.6 4.2 | -11.1 12.0 250 25 13 7.3 4.0
16500 -10.3 13.5 260 25 13 7.8 4.3 | -10.0 14.0 250 24 12 7.7 4.2
16000 -9.1 15.6 260 24 12 8.5 4.7 | -8.8 16.2 245 23 12 8.2 4.5
15500 -7.9 17.8 260 23 12 8.5 4.6 | -7.6 18.3 245 22 11 8.3 4.6
15000 -6.6 20.1 265 22 11 9.0 4.9 | -6.3 20.7 245 20 11 9.2 5.0
14500 -5.3 22.5 265 20 11 9.0 4.9 | -5.0 23.0 245 19 10 9.1 5.0
14000 -3.9 25.0 270 19 10 8.8 4.9 | -3.6 25.5 245 18 9 9.4 5.1
13500 -2.6 27.3 270 18 9 8.8 4.8 | -2.2 28.0 245 17 9 9.4 5.1
13000 -1.3 29.7 270 17 9 8.8 4.9 | -0.8 30.6 245 16 8 9.2 5.1
12500 -0.0 32.0 270 16 8 8.9 4.9 | 0.5 32.9 245 16 8 9.2 5.1
12000 1.3 34.3 265 14 7 8.9 4.9 | 1.9 35.4 245 15 8 9.3 5.1
11500 2.6 36.7 265 13 7 8.9 4.9 | 3.3 37.9 245 14 7 9.3 5.1
11000 3.9 39.0 260 12 6 7.9 4.3 | 4.6 40.3 245 14 7 8.2 4.5
10500 5.0 41.0 255 12 6 6.3 3.4 | 5.8 42.4 245 13 7 6.8 3.7
10250 5.5 41.9 255 12 6 10.6 5.8 | 6.4 43.5 250 13 7 11.5 6.3
10000 6.5 43.7 250 11 6 11.2 6.2 | 7.4 45.3 245 12 6 12.5 6.8
9750 7.1 44.8 250 10 5 7.1 3.9 | 8.1 46.6 245 12 6 8.3 4.5
9500 8.3 46.9 245 9 4 6.7 3.7 | 8.8 47.8 245 11 6 10.0 5.5
9250 8.7 47.7 245 8 4 6.5 3.6 | 9.5 49.1 245 10 5 7.4 4.1
9000 9.3 48.7 240 7 4 7.7 4.2 | 9.9 49.8 245 9 5 8.1 4.5
8750 9.8 49.6 235 6 3 7.6 4.2 | 10.7 51.3 245 9 5 10.7 5.9
8500 10.4 50.7 220 5 3 6.8 3.7 | 12.2 54.0 240 8 4 9.1 5.0
8250 10.9 51.6 205 4 2 5.7 3.1 | 12.8 55.0 245 7 4 8.7 4.8
8000 11.3 52.3 190 4 2 6.5 3.6 | 13.6 56.5 245 7 4 10.4 5.7
7750 11.8 53.2 175 4 2 7.3 4.0 | 14.4 57.9 245 7 4 11.1 6.1
7500 12.3 54.1 160 4 2 6.0 3.3 | 15.1 59.2 240 7 4 9.2 5.1
7250 12.7 54.9 150 5 3 4.8 2.7 | 15.7 60.3 245 6 3 8.0 4.4
7000 13.2 55.8 145 6 3 7.6 4.2 | 16.4 61.5 250 6 3 10.8 5.9
6750 13.8 56.8 140 6 3 8.8 4.9 | 17.3 63.1 245 6 3 11.9 6.5
6500 14.4 57.9 135 6 3 6.8 3.7 | 18.2 64.8 245 6 3 10.5 5.8
6250 14.9 58.8 130 5 3 6.0 3.3 | 18.9 66.0 250 5 3 10.7 5.9
6000 15.3 59.5 120 5 3 6.8 3.8 | 19.7 67.5 255 5 2 8.4 4.6
5750 16.0 60.8 125 4 2 12.4 6.8 | 20.4 68.7 245 5 3 13.6 7.5
5500 17.6 63.7 115 4 2 34.8 19.1 | 23.2 73.8 260 4 2 78.4 43.0
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
04/23/2024 at 1500 MDT | 04/23/2024 at 1800 MDT
|
CAPE... +8.5 LI... +0.5 | CAPE... +1.1 LI... +0.5
CINH... -13.0 K Index... +18.3 | CINH... -5.8 K Index... +14.7
|
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 -58.4 -73.1 280 59 30 -0.1 -0.1 | -57.7 -71.9 280 60 31 0.5 0.3
45000 -58.6 -73.5 270 65 34 -0.5 -0.3 | -57.1 -70.8 275 70 36 -0.9 -0.5
40000 -59.4 -74.9 270 74 38 -0.3 -0.2 | -58.6 -73.5 270 79 41 -0.8 -0.4
38000 -56.0 -68.8 270 70 36 6.9 3.8 | -55.6 -68.1 265 75 39 6.0 3.3
36000 -51.8 -61.2 265 65 34 6.9 3.8 | -52.0 -61.6 265 70 36 6.0 3.3
34000 -47.8 -54.0 265 60 31 6.7 3.7 | -48.0 -54.4 265 64 33 7.5 4.1
32000 -43.8 -46.8 260 55 28 6.7 3.7 | -43.5 -46.3 265 59 30 7.5 4.1
30000 -39.3 -38.7 260 51 26 8.4 4.6 | -38.9 -38.0 265 53 27 7.8 4.3
29000 -36.7 -34.1 260 48 25 8.4 4.6 | -36.5 -33.7 265 50 26 7.8 4.3
28000 -34.2 -29.6 260 46 24 8.4 4.6 | -34.2 -29.6 260 47 24 7.8 4.3
27000 -31.9 -25.4 260 44 23 6.5 3.6 | -31.9 -25.4 260 45 23 6.7 3.7
26000 -29.9 -21.8 260 42 21 6.6 3.6 | -29.9 -21.8 260 41 21 6.8 3.7
25000 -27.9 -18.2 260 39 20 6.6 3.6 | -27.9 -18.2 260 38 20 6.8 3.7
24000 -25.9 -14.6 260 37 19 6.6 3.6 | -25.4 -13.7 260 35 18 6.2 3.4
23000 -23.5 -10.3 255 34 17 6.6 3.6 | -23.6 -10.5 255 32 17 6.3 3.4
22000 -21.5 -6.7 255 32 16 6.6 3.6 | -21.7 -7.1 250 30 15 6.3 3.4
21000 -19.4 -2.9 250 29 15 7.6 4.2 | -19.6 -3.3 245 28 14 7.8 4.3
20000 -17.1 1.2 245 27 14 7.7 4.2 | -17.3 0.9 240 26 13 7.9 4.4
19500 -16.0 3.2 245 26 13 7.7 4.2 | -16.1 3.0 235 25 13 8.0 4.4
19000 -14.9 5.2 240 25 13 7.8 4.3 | -15.0 5.0 230 24 12 8.3 4.5
18500 -13.7 7.3 240 24 12 7.8 4.3 | -13.7 7.3 230 24 12 8.7 4.8
18000 -12.6 9.3 235 24 12 7.8 4.3 | -12.4 9.7 230 23 12 8.7 4.7
17500 -11.4 11.5 235 23 12 8.5 4.7 | -11.1 12.0 230 23 12 9.1 5.0
17000 -10.2 13.6 235 22 11 8.5 4.7 | -9.8 14.4 230 22 11 9.1 5.0
16500 -8.9 16.0 235 21 11 8.6 4.7 | -8.4 16.9 230 22 11 9.2 5.0
16000 -7.6 18.3 230 20 10 8.8 4.8 | -7.0 19.4 230 21 11 9.2 5.1
15500 -6.3 20.7 230 19 10 8.8 4.9 | -5.7 21.7 235 21 11 9.3 5.1
15000 -5.0 23.0 230 19 10 9.3 5.1 | -4.3 24.3 235 21 11 9.4 5.2
14500 -3.6 25.5 235 18 9 9.3 5.1 | -2.9 26.8 235 20 10 9.4 5.2
14000 -2.2 28.0 235 18 9 9.3 5.1 | -1.5 29.3 235 20 10 9.3 5.1
13500 -0.8 30.6 235 17 9 9.3 5.1 | -0.1 31.8 235 20 10 9.3 5.1
13000 0.6 33.1 235 17 9 9.3 5.1 | 1.3 34.3 240 19 10 9.4 5.1
12500 2.0 35.6 240 16 8 9.4 5.1 | 2.7 36.9 240 19 10 9.4 5.1
12000 3.4 38.1 240 16 8 9.4 5.1 | 4.1 39.4 240 18 9 9.4 5.1
11500 4.8 40.6 240 16 8 9.4 5.1 | 5.5 41.9 245 18 9 9.4 5.1
11000 6.1 43.0 245 15 8 8.0 4.4 | 6.9 44.4 245 18 9 8.1 4.5
10500 7.2 45.0 245 15 8 6.5 3.5 | 8.0 46.4 245 17 9 6.8 3.7
10250 7.8 46.0 250 15 8 12.0 6.6 | 8.6 47.5 245 17 9 12.0 6.6
10000 8.9 48.0 250 15 8 13.2 7.3 | 9.7 49.5 245 17 9 12.3 6.7
9750 9.6 49.3 250 15 7 8.5 4.7 | 10.3 50.5 250 16 8 7.9 4.3
9500 10.3 50.5 250 15 7 10.3 5.6 | 11.0 51.8 250 16 8 8.7 4.8
9250 11.1 52.0 255 14 7 8.0 4.4 | 11.6 52.9 250 16 8 9.9 5.4
9000 11.6 52.9 255 15 7 8.6 4.7 | 12.4 54.3 250 15 8 10.5 5.8
8750 12.4 54.3 255 14 7 10.7 5.9 | 13.9 57.0 250 15 8 9.8 5.4
8500 13.2 55.8 255 14 7 10.5 5.8 | 14.6 58.3 250 15 8 9.0 4.9
8250 14.6 58.3 260 14 7 9.0 5.0 | 15.2 59.4 255 15 8 9.0 5.0
8000 15.3 59.5 260 14 7 10.7 5.9 | 16.0 60.8 255 15 8 10.0 5.5
7750 16.1 61.0 260 14 7 11.3 6.2 | 16.7 62.1 255 15 8 10.2 5.6
7500 16.9 62.4 260 14 7 9.1 5.0 | 17.5 63.5 255 14 7 9.4 5.1
7250 17.5 63.5 265 14 7 7.5 4.1 | 18.1 64.6 255 15 8 8.8 4.8
7000 18.2 64.8 265 14 7 10.7 5.9 | 18.8 65.8 255 15 8 10.1 5.5
6750 19.1 66.4 265 13 7 11.9 6.5 | 19.6 67.3 255 14 7 10.7 5.9
6500 19.9 67.8 265 13 7 10.6 5.8 | 20.4 68.7 255 14 7 10.6 5.8
6250 20.7 69.3 265 13 7 10.9 6.0 | 21.2 70.2 255 14 7 11.2 6.1
6000 21.5 70.7 270 13 7 8.3 4.5 | 22.0 71.6 260 14 7 8.4 4.6
5750 22.1 71.8 265 12 6 13.3 7.3 | 22.5 72.5 255 12 6 9.0 5.0
5500 25.0 77.0 270 11 6 81.7 44.8 | 24.3 75.7 260 11 6 50.9 27.9
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.
042613
- National Weather Service
- Central Illinois Weather Forecast Office
- 1362 State Route 10
- Lincoln, IL 62656
- 217-732-7321 (forecast recording) or 217-732-3089
- Page Author: ILX Webmaster
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- Page last modified: Sep 19th, 2023 19:10 UTC