Soaring Guidance
Issued by NWS Grand Junction, CO
Issued by NWS Grand Junction, CO
750
UXUS97 KGJT 151307
SRGGJT
Soaring Forecast
National Weather Service Grand Junction, Colorado
707 AM MDT Saturday, June 15, 2024
This forecast is for Saturday, June 15, 2024:
If the trigger temperature of 81.0 F/27.2 C is reached...then
Thermal Soaring Index....................... Excellent
Maximum rate of lift........................ 1523 ft/min (7.7 m/s)
Maximum height of thermals.................. 21412 ft MSL (16573 ft AGL)
Forecast maximum temperature................... 97.0 F/36.6 C
Time of trigger temperature.................... 0945 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................. 18173 ft MSL (13333 ft AGL)
Thermal soaring outlook for Sunday 06/16....... Excellent
Wave Soaring Index............................. Not available
Remarks...
Sunrise/Sunset.................... 05:47:36 / 20:42:02 MDT
Total possible sunshine........... 14 hr 54 min 26 sec (894 min 26 sec)
Altitude of sun at 13:14:49 MDT... 73.92 degrees
Upper air data from rawinsonde observation taken on 06/15/2024 at 0600 MDT
Freezing level.................. 15462 ft MSL (10623 ft AGL)
Convective condensation level... 15616 ft MSL (10777 ft AGL)
Lifted condensation level....... 17402 ft MSL (12563 ft AGL)
Lifted index.................... -4.3
K index......................... +20.0
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 -59.8 -75.6 275 45 23 2.0 1.1 95.1 203.2 34.2 M M
45000 -56.4 -69.5 265 52 27 4.9 2.7 76.5 169.6 25.0 M M
40000 -51.8 -61.2 270 52 27 5.3 2.9 59.7 139.4 15.7 M M
38000 -48.9 -56.0 265 45 23 4.0 2.2 55.3 131.6 13.1 M M
36000 -46.4 -51.5 265 39 20 4.3 2.4 50.5 123.0 10.1 M M
34000 -42.7 -44.9 265 39 20 8.5 4.7 47.6 117.6 8.2 M M
32000 -37.7 -35.9 270 34 18 7.8 4.3 46.4 115.6 7.6 M M
30000 -32.6 -26.7 275 34 17 8.1 4.4 44.5 112.1 6.4 M M
29000 -30.0 -22.0 275 31 16 8.4 4.6 44.0 111.2 6.0 M M
28000 -27.4 -17.3 275 26 13 9.1 5.0 43.6 110.5 5.8 M M
27000 -24.8 -12.6 275 28 14 8.4 4.6 43.2 109.7 5.5 M M
26000 -22.3 -8.1 275 32 16 8.3 4.6 42.7 108.8 5.2 M M
25000 -19.9 -3.8 285 28 14 8.4 4.6 42.0 107.7 4.8 M M
24000 -17.9 -0.2 290 28 14 6.9 3.8 40.9 105.7 3.9 M M
23000 -16.3 2.7 280 22 11 4.9 2.7 39.4 102.8 2.6 M M
22000 -14.8 5.4 280 21 11 4.7 2.6 37.6 99.7 1.2 M M
21000 -14.1 6.6 285 11 6 3.2 1.7 35.2 95.3 -1.0 1509 7.7
20000 -12.4 9.7 305 13 6 8.8 4.8 33.9 93.0 -2.2 1429 7.3
19500 -11.1 12.0 305 14 7 8.7 4.8 33.7 92.6 -2.4 1376 7.0
19000 -9.8 14.4 300 19 10 8.6 4.7 33.5 92.3 -2.6 1323 6.7
18500 -8.5 16.7 295 22 11 8.6 4.7 33.3 91.9 -2.8 1269 6.4
18000 -7.3 18.9 290 25 13 8.5 4.7 33.1 91.5 -3.0 1217 6.2
17500 -6.0 21.2 290 24 12 9.1 5.0 32.9 91.2 -3.3 1165 5.9
17000 -4.7 23.5 285 23 12 9.2 5.1 32.8 91.0 -3.4 1109 5.6
16500 -2.6 27.3 280 21 11 9.2 5.1 32.7 90.8 -3.5 1025 5.2
16000 -1.2 29.8 280 20 10 9.2 5.1 32.6 90.7 -3.6 969 4.9
15500 0.2 32.4 270 19 10 8.7 4.8 32.5 90.5 -3.7 913 4.6
15000 1.3 34.3 260 18 9 7.5 4.1 32.2 89.9 -4.1 865 4.4
14500 2.3 36.1 260 18 9 7.8 4.3 31.8 89.3 -4.5 819 4.2
14000 3.5 38.3 255 20 10 8.1 4.5 31.6 88.8 -4.8 768 3.9
13500 4.7 40.5 250 17 9 8.2 4.5 31.3 88.4 -5.0 717 3.6
13000 5.9 42.6 245 15 8 8.2 4.5 31.1 88.0 -5.3 666 3.4
12500 7.1 44.8 250 14 7 8.2 4.5 30.8 87.5 -5.6 615 3.1
12000 8.3 46.9 245 19 10 8.2 4.5 30.6 87.0 -5.9 564 2.9
11500 9.5 49.1 250 15 8 8.2 4.5 30.3 86.6 -6.1 514 2.6
11000 10.8 51.4 210 8 4 8.2 4.5 30.1 86.1 -6.4 463 2.4
10500 12.0 53.6 210 8 4 8.1 4.4 29.8 85.6 -6.7 412 2.1
10250 12.5 54.5 205 8 4 7.1 3.9 29.6 85.3 -6.9 387 2.0
10000 13.0 55.4 195 9 5 6.5 3.6 29.4 84.8 -7.2 366 1.9
9750 13.5 56.3 185 10 5 6.7 3.7 29.1 84.4 -7.5 345 1.8
9500 13.9 57.0 180 11 6 6.7 3.7 28.9 84.0 -7.8 323 1.6
9250 14.4 57.9 175 12 6 6.6 3.6 28.6 83.6 -8.1 302 1.5
9000 14.9 58.8 180 13 7 7.1 3.9 28.4 83.1 -8.3 280 1.4
8750 15.3 59.5 180 13 7 5.3 2.9 28.2 82.7 -8.6 259 1.3
8500 15.4 59.7 175 14 7 -3.5 -1.9 27.5 81.5 -9.3 249 1.3
8250 15.0 59.0 160 17 9 -3.0 -1.6 26.3 79.4 -10.5 255 1.3
8000 15.1 59.2 150 20 10 4.8 2.6 25.7 78.3 -11.1 245 1.2
7750 15.5 59.9 150 21 11 6.7 3.7 25.4 77.8 -11.5 225 1.1
7500 16.0 60.8 150 22 11 8.0 4.4 25.2 77.4 -11.7 202 1.0
7250 16.5 61.7 145 19 10 3.3 1.8 25.0 77.0 -12.0 181 0.9
7000 16.4 61.5 145 17 9 -4.0 -2.2 24.2 75.5 -12.9 176 0.9
6750 16.1 61.0 145 15 8 -2.3 -1.3 23.1 73.6 -13.9 178 0.9
6500 16.1 61.0 135 9 5 1.6 0.9 22.4 72.3 -14.7 170 0.9
6250 16.2 61.2 130 7 3 1.8 1.0 21.8 71.2 -15.4 160 0.8
6000 16.3 61.3 140 7 4 0.7 0.4 21.2 70.1 -16.0 150 0.8
5750 16.4 61.5 140 11 5 4.7 2.6 20.5 69.0 -16.7 139 0.7
5500 16.7 62.1 140 11 6 2.2 1.2 20.2 68.4 -17.2 122 0.6
5250 16.4 61.5 135 10 5 -7.9 -4.3 19.2 66.6 -18.3 125 0.6
5000 15.8 60.4 125 8 4 -3.7 -2.0 17.9 64.3 -19.6 134 0.7
* * * * * * Numerical weather prediction model forecast data valid * * * * * *
06/15/2024 at 0900 MDT | 06/15/2024 at 1200 MDT
|
CAPE... +31.9 LI... -0.7 | CAPE... +436.1 LI... -2.2
CINH... -169.9 K Index... +20.8 | CINH... -34.7 K Index... +21.6
|
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 -59.4 -74.9 255 38 20 3.0 1.6 | -59.2 -74.6 245 40 21 3.4 1.8
45000 -55.1 -67.2 260 51 26 2.7 1.5 | -54.6 -66.3 255 52 27 2.2 1.2
40000 -50.7 -59.3 260 51 26 3.7 2.0 | -50.9 -59.6 260 55 28 3.5 1.9
38000 -48.6 -55.5 265 48 25 3.6 2.0 | -48.8 -55.8 260 49 25 3.4 1.9
36000 -46.4 -51.5 265 45 23 3.7 2.0 | -46.8 -52.2 265 44 23 3.5 1.9
34000 -42.7 -44.9 265 43 22 7.0 3.8 | -43.1 -45.6 265 42 22 7.0 3.8
32000 -38.5 -37.3 265 41 21 7.0 3.9 | -39.0 -38.2 265 42 21 7.0 3.8
30000 -33.8 -28.8 265 40 21 8.1 4.5 | -34.3 -29.7 265 40 21 8.1 4.4
29000 -31.4 -24.5 265 40 21 8.1 4.5 | -31.9 -25.4 260 40 20 8.1 4.4
28000 -28.9 -20.0 265 40 21 8.1 4.5 | -29.4 -20.9 260 39 20 8.1 4.5
27000 -26.5 -15.7 265 39 20 7.9 4.3 | -27.2 -17.0 265 38 19 7.4 4.1
26000 -24.2 -11.6 265 36 19 7.9 4.3 | -25.0 -13.0 265 36 18 7.4 4.1
25000 -21.2 -6.2 265 34 17 7.9 4.3 | -22.2 -8.0 265 34 17 7.4 4.1
24000 -19.5 -3.1 265 30 15 5.5 3.0 | -20.2 -4.4 265 31 16 6.4 3.5
23000 -17.8 -0.0 265 26 13 5.6 3.1 | -18.3 -0.9 270 27 14 6.4 3.5
22000 -16.2 2.8 265 21 11 5.9 3.3 | -16.5 2.3 270 24 12 6.6 3.6
21000 -14.2 6.4 265 20 10 7.2 4.0 | -14.3 6.3 270 23 12 7.5 4.1
20000 -12.1 10.2 265 19 10 7.3 4.0 | -12.1 10.2 265 23 12 7.6 4.2
19500 -11.0 12.2 265 19 10 7.2 4.0 | -11.0 12.2 265 23 12 7.6 4.1
19000 -9.9 14.2 265 18 9 8.8 4.8 | -9.8 14.4 260 23 12 8.7 4.8
18500 -8.6 16.5 265 18 9 8.7 4.8 | -8.6 16.5 255 22 11 8.7 4.8
18000 -7.3 18.9 265 18 9 8.9 4.9 | -7.3 18.9 255 22 11 8.9 4.9
17500 -6.0 21.2 265 18 9 9.2 5.0 | -5.9 21.4 250 21 11 9.3 5.1
17000 -4.6 23.7 265 17 9 9.1 5.0 | -4.5 23.9 250 21 11 9.3 5.1
16500 -3.2 26.2 265 17 9 9.4 5.1 | -3.2 26.2 250 21 11 9.2 5.0
16000 -1.8 28.8 265 17 9 9.3 5.1 | -1.8 28.8 250 20 10 9.2 5.1
15500 -0.4 31.3 265 17 9 9.3 5.1 | -0.4 31.3 250 20 10 9.2 5.0
15000 0.9 33.6 265 17 9 9.3 5.1 | 0.9 33.6 250 19 10 9.2 5.0
14500 2.3 36.1 265 17 9 9.1 5.0 | 2.3 36.1 255 19 10 9.2 5.0
14000 3.6 38.5 265 17 9 8.7 4.8 | 3.7 38.7 255 19 10 9.2 5.1
13500 4.9 40.8 265 17 9 8.7 4.8 | 5.0 41.0 255 19 10 9.2 5.1
13000 6.1 43.0 260 17 9 8.1 4.5 | 6.4 43.5 250 18 9 8.8 4.8
12500 7.3 45.1 255 17 9 8.3 4.6 | 7.6 45.7 250 18 9 8.9 4.9
12000 8.4 47.1 250 16 8 7.2 4.0 | 8.9 48.0 245 17 9 8.4 4.6
11500 9.5 49.1 245 15 8 7.5 4.1 | 10.1 50.2 245 17 9 8.6 4.7
11000 10.5 50.9 240 14 7 6.1 3.4 | 11.2 52.2 240 16 8 6.9 3.8
10500 11.4 52.5 235 13 7 5.7 3.1 | 12.2 54.0 240 15 8 8.1 4.4
10250 11.8 53.2 230 13 7 8.1 4.4 | 12.9 55.2 235 15 8 10.8 5.9
10000 12.5 54.5 225 13 6 8.1 4.4 | 13.6 56.5 235 14 7 9.3 5.1
9750 12.9 55.2 220 12 6 5.7 3.1 | 14.2 57.6 230 14 7 7.7 4.2
9500 13.4 56.1 215 12 6 6.3 3.5 | 14.8 58.6 230 13 7 8.5 4.7
9250 13.8 56.8 210 12 6 6.3 3.5 | 15.4 59.7 230 12 6 7.0 3.9
9000 14.3 57.7 210 11 6 5.8 3.2 | 15.9 60.6 230 11 6 7.6 4.2
8750 15.1 59.2 195 12 6 5.5 3.0 | 17.2 63.0 230 10 5 9.0 4.9
8500 15.5 59.9 190 12 6 5.2 2.9 | 17.8 64.0 225 9 5 8.5 4.7
8250 15.8 60.4 190 12 6 4.7 2.6 | 18.4 65.1 230 8 4 9.2 5.0
8000 16.1 61.0 185 11 6 4.3 2.4 | 19.2 66.6 230 8 4 10.4 5.7
7750 16.4 61.5 180 11 6 4.2 2.3 | 19.9 67.8 225 8 4 10.3 5.6
7500 16.7 62.1 175 11 6 3.0 1.7 | 20.7 69.3 225 8 4 8.8 4.8
7250 16.9 62.4 170 11 6 3.1 1.7 | 21.3 70.3 230 7 3 8.4 4.6
7000 17.2 63.0 165 10 5 7.0 3.8 | 22.0 71.6 230 6 3 10.8 5.9
6750 17.8 64.0 160 9 5 9.1 5.0 | 22.9 73.2 225 7 3 11.5 6.3
6500 18.4 65.1 160 9 5 8.6 4.7 | 23.7 74.7 225 6 3 10.7 5.9
6250 19.1 66.4 155 9 5 8.6 4.7 | 24.5 76.1 230 6 3 11.3 6.2
6000 19.7 67.5 150 9 5 9.6 5.2 | 25.3 77.5 230 5 3 7.9 4.3
5750 20.6 69.1 155 7 4 16.4 9.0 | 25.9 78.6 225 6 3 13.0 7.1
5500 22.4 72.3 150 8 4 34.0 18.7 | 28.9 84.0 235 4 2 90.3 49.5
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
06/15/2024 at 1500 MDT | 06/15/2024 at 1800 MDT
|
CAPE... +306.1 LI... -1.0 | CAPE... +20.3 LI... +0.1
CINH... -7.9 K Index... +22.3 | CINH... -21.5 K Index... +15.4
|
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 -58.9 -74.0 245 42 22 3.4 1.9 | -58.9 -74.0 255 42 22 2.5 1.4
45000 -54.4 -65.9 255 49 25 1.8 1.0 | -55.7 -68.3 265 45 23 1.2 0.7
40000 -51.7 -61.1 270 48 25 2.8 1.5 | -53.7 -64.7 295 46 24 4.8 2.7
38000 -49.7 -57.5 270 43 22 3.0 1.6 | -50.7 -59.3 300 44 22 5.0 2.8
36000 -47.9 -54.2 270 39 20 3.0 1.7 | -47.3 -53.1 300 42 21 5.0 2.7
34000 -43.8 -46.8 270 37 19 8.1 4.5 | -42.8 -45.0 300 38 20 8.0 4.4
32000 -38.9 -38.0 270 36 19 8.2 4.5 | -38.0 -36.4 300 35 18 8.0 4.4
30000 -34.2 -29.6 270 35 18 7.6 4.2 | -33.3 -27.9 295 31 16 7.9 4.3
29000 -31.9 -25.4 265 34 18 7.6 4.2 | -30.9 -23.6 295 29 15 7.9 4.3
28000 -29.7 -21.5 265 34 17 7.6 4.2 | -28.6 -19.5 290 27 14 7.8 4.3
27000 -27.4 -17.3 265 33 17 7.5 4.1 | -26.5 -15.7 290 25 13 7.1 3.9
26000 -25.2 -13.4 265 33 17 7.5 4.1 | -24.4 -11.9 285 24 12 7.1 3.9
25000 -22.9 -9.2 265 33 17 7.5 4.1 | -22.3 -8.1 280 23 12 7.1 3.9
24000 -20.3 -4.5 260 31 16 6.9 3.8 | -20.2 -4.4 275 23 12 6.8 3.7
23000 -18.2 -0.8 260 28 15 6.9 3.8 | -17.7 0.1 270 24 12 6.9 3.8
22000 -16.2 2.8 255 26 13 7.4 4.0 | -15.7 3.7 265 25 13 7.4 4.0
21000 -13.8 7.2 250 25 13 8.3 4.6 | -13.2 8.2 260 24 12 8.4 4.6
20000 -11.4 11.5 245 23 12 8.4 4.6 | -10.8 12.6 250 23 12 8.4 4.6
19500 -10.2 13.6 245 23 12 8.4 4.6 | -9.5 14.9 250 23 12 8.3 4.6
19000 -8.9 16.0 240 22 11 8.7 4.8 | -8.3 17.1 245 23 12 9.3 5.1
18500 -7.7 18.1 240 22 11 8.7 4.8 | -6.9 19.6 245 23 12 9.2 5.1
18000 -6.4 20.5 240 22 11 8.8 4.8 | -5.5 22.1 240 22 12 9.4 5.1
17500 -5.1 22.8 240 21 11 8.9 4.9 | -4.1 24.6 240 22 11 9.6 5.3
17000 -3.8 25.2 240 21 11 8.9 4.9 | -2.7 27.1 240 22 11 9.6 5.3
16500 -2.4 27.7 240 21 11 9.2 5.1 | -1.3 29.7 240 22 11 9.3 5.1
16000 -1.1 30.0 240 20 11 9.2 5.0 | 0.1 32.2 240 21 11 9.4 5.1
15500 0.3 32.5 240 20 10 9.3 5.1 | 1.5 34.7 240 21 11 9.4 5.1
15000 1.6 34.9 240 20 10 9.3 5.1 | 2.9 37.2 240 21 11 9.4 5.2
14500 3.0 37.4 240 20 10 9.3 5.1 | 4.3 39.7 240 20 11 9.4 5.2
14000 4.4 39.9 240 19 10 9.2 5.1 | 5.7 42.3 240 20 10 9.6 5.3
13500 5.8 42.4 240 19 10 9.2 5.1 | 7.2 45.0 240 20 10 9.6 5.3
13000 7.2 45.0 240 19 10 9.5 5.2 | 8.6 47.5 240 19 10 9.4 5.2
12500 8.6 47.5 240 19 10 9.5 5.2 | 10.0 50.0 240 19 10 9.5 5.2
12000 10.0 50.0 240 18 10 9.3 5.1 | 11.4 52.5 240 19 10 9.3 5.1
11500 11.4 52.5 240 18 9 9.5 5.2 | 12.8 55.0 240 18 9 9.4 5.1
11000 12.7 54.9 240 17 9 8.3 4.6 | 14.1 57.4 245 18 9 8.1 4.4
10500 13.9 57.0 245 16 8 9.8 5.4 | 15.2 59.4 245 17 9 9.6 5.3
10250 14.8 58.6 245 16 8 11.9 6.5 | 16.1 61.0 245 17 9 12.0 6.6
10000 15.6 60.1 245 16 8 10.2 5.6 | 16.9 62.4 245 16 8 9.7 5.3
9750 16.3 61.3 245 16 8 9.4 5.1 | 17.5 63.5 245 16 8 8.5 4.7
9500 17.0 62.6 245 16 8 9.8 5.4 | 18.2 64.8 250 16 8 8.4 4.6
9250 17.7 63.9 245 15 8 8.9 4.9 | 18.8 65.8 250 15 8 9.9 5.4
9000 18.3 64.9 245 14 7 9.4 5.1 | 19.6 67.3 245 14 7 10.6 5.8
8750 19.8 67.6 250 14 7 10.3 5.6 | 21.1 70.0 250 14 7 9.9 5.4
8500 20.6 69.1 250 14 7 9.9 5.4 | 21.8 71.2 250 14 7 9.4 5.2
8250 21.3 70.3 250 14 7 9.9 5.4 | 22.5 72.5 255 15 8 9.6 5.3
8000 22.1 71.8 250 14 7 10.2 5.6 | 23.3 73.9 250 14 7 10.0 5.5
7750 22.8 73.0 250 14 7 10.4 5.7 | 24.0 75.2 250 13 7 10.2 5.6
7500 23.6 74.5 250 14 7 9.2 5.0 | 24.7 76.5 250 13 7 9.0 4.9
7250 24.2 75.6 255 13 7 8.9 4.9 | 25.4 77.7 255 14 7 8.5 4.7
7000 25.0 77.0 255 13 7 10.6 5.8 | 26.1 79.0 255 14 7 10.2 5.6
6750 25.8 78.4 255 13 7 11.1 6.1 | 26.8 80.2 255 12 6 10.7 5.8
6500 26.6 79.9 255 13 7 11.1 6.1 | 27.6 81.7 255 12 6 10.7 5.9
6250 27.5 81.5 255 12 6 12.0 6.6 | 28.5 83.3 255 12 6 11.3 6.2
6000 28.3 82.9 260 12 6 7.7 4.2 | 29.2 84.6 260 13 6 8.3 4.6
5750 28.8 83.8 255 12 6 12.5 6.9 | 29.8 85.6 255 11 6 10.0 5.5
5500 32.0 89.6 260 10 5 96.1 52.7 | 31.8 89.2 260 10 5 56.6 31.1
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
________________________________________________________________________________
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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