Soaring Guidance
Issued by NWS Grand Junction, CO
Issued by NWS Grand Junction, CO
523
UXUS97 KGJT 261306
SRGGJT
Soaring Forecast
National Weather Service Grand Junction, Colorado
706 AM MDT Wednesday, June 26, 2024
This forecast is for Wednesday, June 26, 2024:
If the trigger temperature of 90.1 F/32.3 C is reached...then
Thermal Soaring Index....................... Excellent
Maximum rate of lift........................ 828 ft/min (4.2 m/s)
Maximum height of thermals.................. 14188 ft MSL (9349 ft AGL)
Forecast maximum temperature................... 95.0 F/35.5 C
Time of trigger temperature.................... 1130 MDT
Time of overdevelopment........................ 1300 MDT
Middle/high clouds during soaring window....... Broken/overcast thin middle
Surface winds during soaring window............ 20 mph or less
Height of the -3 thermal index................. 8399 ft MSL (3560 ft AGL)
Thermal soaring outlook for Thursday 06/27..... Excellent
Wave Soaring Index............................. Not available
Remarks...
Sunrise/Sunset.................... 05:50:06 / 20:44:16 MDT
Total possible sunshine........... 14 hr 54 min 10 sec (894 min 10 sec)
Altitude of sun at 13:17:11 MDT... 73.79 degrees
Upper air data from rawinsonde observation taken on 06/26/2024 at 0600 MDT
Freezing level.................. 16702 ft MSL (11863 ft AGL)
Convective condensation level... 16750 ft MSL (11911 ft AGL)
Lifted condensation level....... 16631 ft MSL (11792 ft AGL)
Lifted index.................... -2.0
K index......................... +26.7
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 -67.4 -89.3 265 20 10 5.7 3.1 80.0 176.0 26.2 M M
45000 -57.9 -72.2 270 39 20 8.6 4.7 70.3 158.6 22.2 M M
40000 -47.6 -53.7 260 52 27 5.6 3.1 63.7 146.7 19.2 M M
38000 -43.9 -47.0 260 60 31 6.9 3.8 60.5 140.9 17.5 M M
36000 -39.8 -39.6 265 56 29 7.5 4.1 58.0 136.4 16.2 M M
34000 -34.9 -30.8 260 55 28 8.6 4.7 56.5 133.8 15.6 M M
32000 -31.4 -24.5 260 35 18 4.5 2.5 52.5 126.6 12.9 M M
30000 -26.4 -15.5 255 34 17 7.5 4.1 51.5 124.6 12.4 M M
29000 -24.1 -11.4 260 34 17 7.6 4.2 50.6 123.1 11.9 M M
28000 -21.8 -7.2 275 26 13 7.6 4.2 49.8 121.6 11.4 M M
27000 -19.7 -3.5 250 17 9 3.4 1.9 48.8 119.8 10.7 M M
26000 -20.2 -4.4 255 15 8 9.0 5.0 44.6 112.2 7.4 M M
25000 -17.7 0.1 250 11 5 8.3 4.6 44.1 111.3 7.0 M M
24000 -15.2 4.6 265 7 4 8.3 4.6 43.5 110.3 6.7 M M
23000 -13.4 7.9 240 12 6 5.6 3.1 42.2 108.0 5.6 M M
22000 -11.8 10.8 195 11 6 5.9 3.3 40.7 105.3 4.4 M M
21000 -9.8 14.4 200 7 4 8.9 4.9 39.7 103.4 3.5 M M
20000 -7.3 18.9 210 9 5 8.6 4.7 39.3 102.7 3.2 M M
19500 -6.0 21.2 210 10 5 8.7 4.8 39.0 102.3 3.0 M M
19000 -4.6 23.7 205 8 4 9.7 5.3 38.9 102.1 2.9 M M
18500 -3.5 25.7 220 8 4 5.3 2.9 38.6 101.5 2.6 M M
18000 -2.5 27.5 220 10 5 5.1 2.8 37.4 99.3 1.4 M M
17500 -1.9 28.6 215 10 5 7.2 3.9 36.6 97.8 0.6 M M
17000 -0.5 31.1 235 8 4 8.9 4.9 36.5 97.7 0.5 M M
16500 0.8 33.4 235 6 3 9.1 5.0 36.4 97.6 0.4 M M
16000 2.2 36.0 250 5 3 9.1 5.0 36.4 97.4 0.3 M M
15500 3.5 38.3 240 4 2 9.1 5.0 36.3 97.3 0.3 M M
15000 4.9 40.8 230 3 2 9.1 5.0 36.2 97.1 0.2 M M
14500 6.2 43.2 210 3 2 9.1 5.0 36.1 96.9 0.0 M M
14000 7.5 45.5 195 4 2 9.1 5.0 36.0 96.7 -0.0 801 4.1
13500 8.9 48.0 190 5 2 9.1 5.0 35.8 96.5 -0.2 746 3.8
13000 10.2 50.4 110 2 1 9.1 5.0 35.7 96.3 -0.3 691 3.5
12500 11.6 52.9 110 2 1 9.1 5.0 35.6 96.1 -0.4 636 3.2
12000 12.9 55.2 135 4 2 9.1 5.0 35.5 95.8 -0.6 581 2.9
11500 14.3 57.7 120 4 2 9.1 5.0 35.3 95.6 -0.7 525 2.7
11000 15.6 60.1 100 6 3 9.0 4.9 35.2 95.3 -0.9 470 2.4
10500 17.0 62.6 075 4 2 8.0 4.4 35.0 95.0 -1.0 415 2.1
10250 17.5 63.5 085 2 1 6.5 3.6 34.8 94.6 -1.2 393 2.0
10000 18.0 64.4 085 2 1 6.8 3.7 34.6 94.2 -1.5 371 1.9
9750 18.4 65.1 195 1 1 6.7 3.7 34.3 93.8 -1.7 349 1.8
9500 18.9 66.0 045 1 0 6.7 3.7 34.1 93.3 -2.0 327 1.7
9250 19.4 66.9 360 3 2 6.7 3.7 33.8 92.9 -2.2 305 1.5
9000 19.9 67.8 355 6 3 7.1 3.9 33.6 92.5 -2.5 282 1.4
8750 20.4 68.7 355 4 2 7.3 4.0 33.4 92.2 -2.7 259 1.3
8500 21.0 69.8 350 3 2 7.3 4.0 33.2 91.8 -2.9 236 1.2
8250 21.5 70.7 335 3 1 7.3 4.0 33.0 91.5 -3.1 213 1.1
8000 22.0 71.6 315 2 1 7.2 4.0 32.9 91.1 -3.3 190 1.0
7750 22.5 72.5 320 2 1 7.6 4.2 32.7 90.8 -3.5 167 0.8
7500 23.0 73.4 000 0 0 4.8 2.6 32.4 90.4 -3.8 145 0.7
7250 23.2 73.8 110 2 1 2.6 1.4 31.9 89.5 -4.3 131 0.7
7000 23.4 74.1 110 5 3 2.8 1.5 31.4 88.5 -4.8 117 0.6
6750 23.5 74.3 120 7 4 -1.1 -0.6 30.7 87.3 -5.5 107 0.5
6500 23.5 74.3 125 8 4 1.3 0.7 29.9 85.8 -6.3 102 0.5
6250 23.8 74.8 135 9 5 7.5 4.1 29.6 85.2 -6.7 84 0.4
6000 24.4 75.9 140 11 5 8.3 4.5 29.4 85.0 -6.8 60 0.3
5750 24.9 76.8 135 11 5 7.7 4.2 29.3 84.7 -7.0 35 0.2
5500 25.5 77.9 130 10 5 10.5 5.8 29.2 84.6 -7.2 11 0.1
5250 26.1 79.0 120 12 6 2.4 1.3 29.1 84.5 -7.4 M M
5000 25.3 77.5 110 13 7 -24.4 -13.4 27.6 81.7 -8.9 3 0.0
* * * * * * Numerical weather prediction model forecast data valid * * * * * *
06/26/2024 at 0900 MDT | 06/26/2024 at 1200 MDT
|
CAPE... +4.2 LI... +0.1 | CAPE... +108.3 LI... -1.0
CINH... -17.4 K Index... +27.0 | CINH... -55.7 K Index... +30.1
|
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 -65.3 -85.5 260 34 18 3.0 1.6 | -64.9 -84.8 265 34 18 1.8 1.0
45000 -58.5 -73.3 265 44 23 6.9 3.8 | -59.2 -74.6 265 43 22 7.1 3.9
40000 -47.7 -53.9 260 49 25 6.7 3.7 | -48.1 -54.6 260 47 24 6.9 3.8
38000 -43.6 -46.5 260 49 25 6.7 3.7 | -43.9 -47.0 255 47 24 6.9 3.8
36000 -39.6 -39.3 260 50 26 6.7 3.7 | -39.8 -39.6 255 47 24 7.0 3.9
34000 -35.5 -31.9 260 45 23 6.8 3.7 | -35.5 -31.9 250 43 22 7.1 3.9
32000 -31.5 -24.7 255 39 20 7.3 4.0 | -31.3 -24.3 245 39 20 7.8 4.3
30000 -27.3 -17.1 255 31 16 7.0 3.9 | -27.1 -16.8 245 31 16 7.0 3.8
29000 -25.2 -13.4 255 27 14 7.1 3.9 | -25.0 -13.0 245 27 14 7.0 3.8
28000 -23.1 -9.6 255 24 12 7.3 4.0 | -23.0 -9.4 245 24 12 7.1 3.9
27000 -20.4 -4.7 250 22 11 7.4 4.0 | -20.9 -5.6 245 23 12 7.2 3.9
26000 -18.2 -0.8 245 21 11 7.4 4.1 | -18.2 -0.8 240 22 11 7.2 4.0
25000 -16.1 3.0 240 20 10 6.3 3.4 | -16.2 2.8 235 21 11 6.5 3.6
24000 -14.3 6.3 235 18 9 6.2 3.4 | -14.3 6.3 235 20 10 6.5 3.6
23000 -12.5 9.5 225 16 8 6.2 3.4 | -12.4 9.7 230 19 10 6.5 3.6
22000 -10.7 12.7 220 15 7 6.3 3.4 | -10.5 13.1 230 18 9 6.3 3.4
21000 -8.8 16.2 215 14 7 6.3 3.5 | -8.7 16.3 225 17 9 6.3 3.5
20000 -7.0 19.4 210 13 7 6.4 3.5 | -6.8 19.8 225 17 9 6.4 3.5
19500 -6.1 21.0 210 13 7 6.6 3.6 | -5.9 21.4 225 16 8 6.7 3.7
19000 -5.1 22.8 205 13 7 7.0 3.8 | -4.9 23.2 220 16 8 7.1 3.9
18500 -4.1 24.6 205 13 7 7.0 3.8 | -3.9 25.0 220 16 8 7.1 3.9
18000 -3.0 26.6 205 13 7 7.8 4.3 | -2.8 27.0 220 15 8 7.5 4.1
17500 -1.9 28.6 205 13 7 7.8 4.3 | -1.8 28.8 215 15 8 7.5 4.1
17000 -0.8 30.6 205 13 7 8.0 4.4 | -0.7 30.7 215 15 8 7.7 4.2
16500 0.4 32.7 200 13 7 8.2 4.5 | 0.5 32.9 210 15 8 8.0 4.4
16000 1.6 34.9 200 13 7 8.1 4.5 | 1.6 34.9 210 15 8 8.0 4.4
15500 2.8 37.0 195 12 6 8.7 4.8 | 2.9 37.2 210 15 8 8.5 4.6
15000 4.1 39.4 190 12 6 8.6 4.7 | 4.1 39.4 205 15 8 8.4 4.6
14500 5.4 41.7 190 11 6 9.0 4.9 | 5.4 41.7 205 15 7 8.8 4.8
14000 6.8 44.2 185 10 5 9.0 5.0 | 6.7 44.1 205 14 7 8.8 4.8
13500 8.2 46.8 180 10 5 8.8 4.8 | 8.0 46.4 205 14 7 8.9 4.9
13000 9.5 49.1 180 9 5 8.6 4.7 | 9.3 48.7 205 14 7 8.9 4.9
12500 10.8 51.4 180 9 5 8.5 4.6 | 10.6 51.1 205 13 7 8.9 4.9
12000 12.0 53.6 180 9 4 8.1 4.4 | 12.0 53.6 205 13 7 8.9 4.9
11500 13.2 55.8 180 8 4 8.0 4.4 | 13.3 55.9 205 12 6 8.9 4.9
11000 14.4 57.9 180 8 4 7.6 4.2 | 14.6 58.3 205 11 6 8.6 4.7
10500 15.5 59.9 180 7 4 6.3 3.5 | 15.9 60.6 205 11 6 7.1 3.9
10250 15.9 60.6 180 7 4 6.6 3.6 | 16.4 61.5 210 10 5 7.6 4.2
10000 16.5 61.7 180 7 4 8.5 4.7 | 17.1 62.8 210 10 5 9.9 5.5
9750 17.1 62.8 180 7 4 8.0 4.4 | 17.8 64.0 210 9 5 9.3 5.1
9500 17.7 63.9 185 7 3 8.1 4.4 | 18.5 65.3 210 9 5 9.4 5.2
9250 18.8 65.8 185 6 3 7.0 3.8 | 19.2 66.6 210 8 4 8.9 4.9
9000 19.3 66.7 185 6 3 7.0 3.8 | 19.8 67.6 210 7 4 8.5 4.7
8750 19.8 67.6 185 6 3 6.7 3.7 | 21.1 70.0 215 7 4 8.2 4.5
8500 20.3 68.5 180 6 3 5.7 3.1 | 21.7 71.1 215 6 3 6.3 3.5
8250 20.7 69.3 180 6 3 5.7 3.2 | 22.1 71.8 215 5 3 7.9 4.3
8000 21.2 70.2 175 6 3 6.5 3.6 | 22.9 73.2 215 6 3 10.5 5.8
7750 21.6 70.9 175 6 3 5.4 3.0 | 23.6 74.5 215 6 3 8.5 4.6
7500 21.9 71.4 170 6 3 3.7 2.0 | 24.1 75.4 215 5 3 6.0 3.3
7250 22.2 72.0 170 6 3 4.5 2.5 | 24.6 76.3 210 4 2 7.2 3.9
7000 22.6 72.7 165 6 3 7.7 4.2 | 25.2 77.4 210 4 2 11.1 6.1
6750 23.2 73.8 160 5 3 7.2 4.0 | 26.1 79.0 210 4 2 11.1 6.1
6500 23.6 74.5 155 4 2 5.5 3.0 | 26.8 80.2 215 3 2 9.8 5.4
6250 24.1 75.4 155 4 2 5.4 3.0 | 27.5 81.5 215 3 1 9.4 5.1
6000 24.5 76.1 150 4 2 8.7 4.8 | 28.3 82.9 220 2 1 11.6 6.4
5750 25.4 77.7 145 3 2 17.4 9.6 | 29.4 84.9 220 3 1 22.5 12.4
5500 26.6 79.9 140 3 2 9.4 5.2 | 31.5 88.7 230 1 1 31.0 17.0
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
06/26/2024 at 1500 MDT | 06/26/2024 at 1800 MDT
|
CAPE... +342.4 LI... -2.3 | CAPE... +428.1 LI... -2.1
CINH... -23.1 K Index... +32.2 | CINH... -110.1 K Index... +31.3
|
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 -64.8 -84.6 260 32 17 1.8 1.0 | -65.0 -85.0 250 32 16 1.8 1.0
45000 -58.7 -73.7 255 44 22 7.0 3.8 | -58.9 -74.0 250 44 23 7.0 3.8
40000 -48.3 -54.9 255 51 26 6.8 3.8 | -48.4 -55.1 250 51 26 7.1 3.9
38000 -44.2 -47.6 250 49 25 6.8 3.8 | -44.1 -47.4 245 48 25 7.1 3.9
36000 -40.1 -40.2 250 47 24 7.1 3.9 | -39.8 -39.6 245 46 24 7.6 4.2
34000 -35.2 -31.4 245 42 22 7.2 4.0 | -35.1 -31.2 240 42 22 7.7 4.2
32000 -30.9 -23.6 240 39 20 7.9 4.3 | -30.5 -22.9 235 38 20 8.3 4.5
30000 -26.6 -15.9 245 33 17 7.3 4.0 | -26.1 -15.0 235 34 18 7.4 4.1
29000 -24.4 -11.9 245 30 15 7.3 4.0 | -23.9 -11.0 235 32 17 7.4 4.1
28000 -22.2 -8.0 245 27 14 7.3 4.0 | -21.7 -7.1 235 30 16 6.6 3.6
27000 -20.0 -4.0 240 26 13 7.4 4.0 | -19.2 -2.6 240 27 14 6.7 3.6
26000 -17.9 -0.2 240 24 12 7.4 4.1 | -17.3 0.9 245 24 13 6.7 3.7
25000 -15.7 3.7 235 23 12 6.9 3.8 | -15.3 4.5 250 22 11 6.7 3.7
24000 -13.8 7.2 240 22 11 6.5 3.6 | -13.3 8.1 255 21 11 6.7 3.7
23000 -11.9 10.6 240 21 11 6.6 3.6 | -11.4 11.5 255 20 10 6.8 3.7
22000 -9.6 14.7 245 20 10 6.0 3.3 | -9.5 14.9 260 19 10 6.1 3.3
21000 -7.9 17.8 245 19 10 6.1 3.4 | -7.8 18.0 260 19 10 6.0 3.3
20000 -6.1 21.0 245 17 9 6.2 3.4 | -6.0 21.2 260 18 9 6.1 3.3
19500 -5.2 22.6 240 16 8 6.7 3.7 | -5.1 22.8 260 18 9 6.3 3.4
19000 -4.2 24.4 240 16 8 7.1 3.9 | -4.2 24.4 260 18 9 6.7 3.7
18500 -3.2 26.2 240 15 8 7.1 3.9 | -3.2 26.2 260 18 9 6.7 3.7
18000 -2.2 28.0 240 15 8 7.2 4.0 | -2.2 28.0 260 18 9 7.3 4.0
17500 -1.2 29.8 240 15 8 7.2 4.0 | -1.2 29.8 260 18 9 7.4 4.0
17000 -0.1 31.8 240 14 7 7.4 4.1 | -0.1 31.8 265 18 9 7.5 4.1
16500 1.0 33.8 240 14 7 7.6 4.2 | 1.0 33.8 265 17 9 7.9 4.3
16000 2.1 35.8 235 14 7 7.7 4.2 | 2.1 35.8 265 17 9 7.8 4.3
15500 3.3 37.9 235 14 7 8.6 4.7 | 3.3 37.9 265 17 9 8.5 4.7
15000 4.5 40.1 235 13 7 8.5 4.7 | 4.5 40.1 265 16 8 8.4 4.6
14500 5.8 42.4 235 13 7 8.9 4.9 | 5.8 42.4 260 16 8 9.0 4.9
14000 7.1 44.8 235 13 7 9.0 4.9 | 7.1 44.8 260 15 8 9.2 5.0
13500 8.4 47.1 235 13 7 9.1 5.0 | 8.5 47.3 260 14 7 9.1 5.0
13000 9.7 49.5 235 13 6 9.1 5.0 | 9.8 49.6 255 13 7 8.9 4.9
12500 11.1 52.0 235 12 6 9.2 5.0 | 11.1 52.0 250 13 7 8.8 4.9
12000 12.4 54.3 235 12 6 9.3 5.1 | 12.4 54.3 245 12 6 8.4 4.6
11500 13.8 56.8 235 12 6 9.3 5.1 | 13.6 56.5 235 11 6 8.4 4.6
11000 15.1 59.2 235 11 6 9.0 4.9 | 14.8 58.6 225 11 6 7.4 4.0
10500 16.5 61.7 235 10 5 10.0 5.5 | 15.8 60.4 220 11 6 9.8 5.4
10250 17.3 63.1 235 10 5 10.0 5.5 | 16.7 62.1 210 12 6 10.3 5.7
10000 17.9 64.2 235 10 5 8.7 4.8 | 17.2 63.0 205 12 6 7.4 4.1
9750 18.6 65.5 230 10 5 8.9 4.9 | 17.8 64.0 200 12 6 8.2 4.5
9500 19.3 66.7 230 9 5 9.4 5.2 | 18.4 65.1 195 12 6 7.9 4.3
9250 20.0 68.0 230 8 4 9.6 5.3 | 19.0 66.2 195 13 6 7.4 4.0
9000 20.6 69.1 230 8 4 8.7 4.8 | 20.1 68.2 185 13 7 7.9 4.3
8750 21.3 70.3 230 8 4 8.5 4.7 | 20.6 69.1 185 13 7 7.7 4.2
8500 21.9 71.4 225 8 4 8.6 4.7 | 21.2 70.2 180 14 7 8.0 4.4
8250 23.2 73.8 225 6 3 8.9 4.9 | 21.8 71.2 180 15 7 7.3 4.0
8000 23.9 75.0 225 6 3 9.6 5.3 | 22.3 72.1 180 15 8 6.6 3.6
7750 24.6 76.3 220 7 3 9.2 5.1 | 22.7 72.9 175 15 8 6.7 3.7
7500 25.2 77.4 220 6 3 8.7 4.7 | 23.2 73.8 175 15 8 6.1 3.4
7250 25.9 78.6 215 6 3 9.1 5.0 | 23.6 74.5 175 16 8 6.3 3.5
7000 26.6 79.9 215 6 3 10.3 5.6 | 24.1 75.4 175 16 8 7.4 4.1
6750 27.4 81.3 215 6 3 10.6 5.8 | 24.6 76.3 170 15 8 7.7 4.2
6500 28.2 82.8 215 5 3 10.6 5.8 | 25.2 77.4 170 15 8 7.5 4.1
6250 28.9 84.0 210 5 3 10.3 5.6 | 25.7 78.3 170 14 7 7.4 4.1
6000 29.7 85.5 205 5 2 9.9 5.4 | 26.1 79.0 170 14 7 6.5 3.6
5750 30.5 86.9 215 5 3 15.5 8.5 | 26.6 79.9 165 12 6 10.9 6.0
5500 32.4 90.3 205 4 2 40.6 22.3 | 28.3 82.9 165 10 5 40.6 22.3
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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