Soaring Guidance
Issued by NWS Grand Junction, CO
Issued by NWS Grand Junction, CO
447
UXUS97 KGJT 131307
SRGGJT
Soaring Forecast
National Weather Service Grand Junction, Colorado
707 AM MDT Thursday, June 13, 2024
This forecast is for Thursday, June 13, 2024:
If the trigger temperature of 91.5 F/33.0 C is reached...then
Thermal Soaring Index....................... Excellent
Maximum rate of lift........................ 1732 ft/min (8.8 m/s)
Maximum height of thermals.................. 22346 ft MSL (17507 ft AGL)
Forecast maximum temperature................... 101.0 F/38.8 C
Time of trigger temperature.................... 1130 MDT
Time of overdevelopment........................ 1900 MDT
Middle/high clouds during soaring window....... None
Surface winds during soaring window............ 20 mph or less
Height of the -3 thermal index................. 13356 ft MSL (8517 ft AGL)
Thermal soaring outlook for Friday 06/14....... Excellent
Wave Soaring Index............................. Not available
Remarks...
Sunrise/Sunset.................... 05:47:31 / 20:41:16 MDT
Total possible sunshine........... 14 hr 53 min 44 sec (893 min 44 sec)
Altitude of sun at 13:14:23 MDT... 73.86 degrees
Upper air data from rawinsonde observation taken on 06/13/2024 at 0600 MDT
Freezing level.................. 16580 ft MSL (11741 ft AGL)
Convective condensation level... 22172 ft MSL (17333 ft AGL)
Lifted condensation level....... 22440 ft MSL (17601 ft AGL)
Lifted index.................... -0.4
K index......................... +7.2
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 -63.0 -81.4 265 47 24 -1.8 -1.0 88.1 190.5 28.9 M M
45000 -56.9 -70.4 255 58 30 -8.2 -4.5 73.9 165.1 22.2 M M
40000 -51.8 -61.2 265 50 26 4.8 2.7 59.1 138.4 13.8 M M
38000 -48.5 -55.3 250 45 23 6.4 3.5 55.2 131.4 11.5 M M
36000 -44.6 -48.3 260 40 21 5.8 3.2 52.3 126.2 9.8 M M
34000 -40.8 -41.4 260 29 15 7.1 3.9 48.5 119.3 7.4 M M
32000 -36.4 -33.5 265 29 15 7.1 3.9 46.6 115.9 6.1 M M
30000 -31.7 -25.1 285 37 19 9.3 5.1 45.1 113.1 5.1 M M
29000 -28.9 -20.0 280 32 16 8.5 4.7 44.8 112.7 5.0 M M
28000 -26.8 -16.2 265 29 15 6.1 3.3 43.8 110.9 4.3 M M
27000 -24.9 -12.8 260 34 18 6.3 3.5 42.4 108.4 3.2 M M
26000 -23.2 -9.8 250 30 16 6.2 3.4 40.9 105.6 2.0 M M
25000 -21.2 -6.2 245 32 16 8.8 4.9 39.7 103.5 1.1 M M
24000 -18.7 -1.7 245 32 16 8.4 4.6 39.4 102.8 0.8 M M
23000 -16.1 3.0 250 31 16 8.4 4.6 38.9 101.9 0.3 M M
22000 -13.7 7.3 265 26 14 7.2 4.0 38.3 100.9 -0.2 1704 8.7
21000 -11.8 10.8 250 25 13 6.6 3.6 37.1 98.8 -1.2 1617 8.2
20000 -9.9 14.2 245 25 13 6.8 3.7 36.0 96.8 -2.3 1531 7.8
19500 -8.8 16.2 250 25 13 8.7 4.8 35.7 96.2 -2.6 1483 7.5
19000 -7.4 18.7 255 24 12 9.7 5.3 35.6 96.1 -2.7 1427 7.2
18500 -5.3 22.5 255 24 12 9.6 5.3 35.7 96.2 -2.7 1340 6.8
18000 -3.8 25.2 260 23 12 9.6 5.3 35.7 96.2 -2.7 1282 6.5
17500 -2.4 27.7 260 23 12 9.6 5.3 35.7 96.2 -2.7 1224 6.2
17000 -0.9 30.4 255 21 11 9.6 5.3 35.7 96.2 -2.7 1166 5.9
16500 0.5 32.9 255 22 11 9.6 5.3 35.7 96.2 -2.7 1108 5.6
16000 1.9 35.4 255 20 10 9.6 5.3 35.7 96.2 -2.7 1050 5.3
15500 3.4 38.1 255 18 9 9.6 5.3 35.6 96.2 -2.8 992 5.0
15000 4.8 40.6 260 16 8 9.6 5.3 35.6 96.1 -2.8 935 4.7
14500 6.2 43.2 265 17 9 9.6 5.3 35.6 96.0 -2.9 877 4.5
14000 7.7 45.9 270 18 9 9.6 5.3 35.5 96.0 -2.9 819 4.2
13500 9.1 48.4 270 16 8 9.6 5.3 35.5 95.9 -3.0 761 3.9
13000 10.6 51.1 265 18 9 9.6 5.3 35.4 95.7 -3.1 703 3.6
12500 12.0 53.6 275 15 8 9.6 5.3 35.3 95.6 -3.2 645 3.3
12000 13.4 56.1 285 13 7 9.6 5.3 35.3 95.5 -3.2 587 3.0
11500 14.8 58.6 290 13 7 9.3 5.1 35.2 95.3 -3.3 530 2.7
11000 16.2 61.2 285 13 7 9.2 5.0 35.1 95.2 -3.5 475 2.4
10500 17.5 63.5 285 12 6 7.6 4.2 35.0 95.1 -3.6 420 2.1
10250 18.0 64.4 280 11 6 6.1 3.3 34.7 94.5 -3.9 399 2.0
10000 18.5 65.3 280 12 6 7.2 3.9 34.5 94.2 -4.1 376 1.9
9750 19.0 66.2 280 12 6 6.9 3.8 34.3 93.8 -4.3 353 1.8
9500 19.6 67.3 280 13 7 7.0 3.8 34.1 93.4 -4.5 329 1.7
9250 20.1 68.2 275 14 7 6.9 3.8 33.9 93.0 -4.7 306 1.6
9000 20.6 69.1 265 15 8 6.9 3.8 33.7 92.6 -4.9 283 1.4
8750 21.2 70.2 265 15 8 6.9 3.8 33.4 92.2 -5.1 259 1.3
8500 21.7 71.1 260 16 8 6.9 3.8 33.2 91.8 -5.4 236 1.2
8250 22.2 72.0 260 14 7 7.0 3.8 33.0 91.4 -5.6 213 1.1
8000 22.7 72.9 260 9 5 6.9 3.8 32.8 91.0 -5.8 190 1.0
7750 23.3 73.9 255 7 3 7.2 3.9 32.6 90.6 -6.0 166 0.8
7500 23.8 74.8 255 4 2 6.1 3.3 32.4 90.2 -6.2 143 0.7
7250 24.2 75.6 210 2 1 4.8 2.7 32.0 89.6 -6.6 125 0.6
7000 24.5 76.1 155 4 2 5.7 3.1 31.7 89.0 -7.0 107 0.5
6750 24.7 76.5 135 6 3 -2.9 -1.6 31.1 88.0 -7.6 94 0.5
6500 24.3 75.7 130 7 4 0.8 0.5 30.0 86.1 -8.7 99 0.5
6250 24.8 76.6 140 8 4 9.5 5.2 29.9 85.8 -8.9 75 0.4
6000 25.4 77.7 125 7 4 9.4 5.2 29.8 85.6 -9.1 51 0.3
5750 26.0 78.8 125 7 4 1.5 0.8 29.7 85.4 -9.3 27 0.1
5500 25.2 77.4 120 8 4 -17.6 -9.7 28.2 82.8 -10.8 41 0.2
5250 23.6 74.5 120 9 5 -22.9 -12.6 25.9 78.6 -13.2 84 0.4
5000 21.9 71.4 115 10 5 -21.2 -11.6 23.5 74.3 -15.7 127 0.6
* * * * * * Numerical weather prediction model forecast data valid * * * * * *
06/13/2024 at 0900 MDT | 06/13/2024 at 1200 MDT
|
CAPE... 0.0 LI... +1.9 | CAPE... +0.5 LI... +1.5
CINH... 0.0 K Index... +7.0 | CINH... -0.5 K Index... +10.8
|
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 -60.9 -77.6 260 43 22 2.8 1.6 | -60.6 -77.1 255 39 20 2.8 1.5
45000 -56.5 -69.7 260 59 30 3.3 1.8 | -56.4 -69.5 250 57 29 2.9 1.6
40000 -51.2 -60.2 255 58 30 5.6 3.1 | -51.6 -60.9 250 63 32 5.5 3.0
38000 -47.8 -54.0 255 54 28 5.6 3.1 | -48.3 -54.9 250 56 29 5.6 3.1
36000 -44.0 -47.2 255 49 25 5.7 3.2 | -44.5 -48.1 250 47 24 5.8 3.2
34000 -40.3 -40.5 255 41 21 6.2 3.4 | -40.6 -41.1 250 40 21 6.6 3.6
32000 -36.6 -33.9 255 32 17 6.0 3.3 | -36.7 -34.1 250 33 17 6.5 3.6
30000 -32.2 -26.0 265 28 14 7.5 4.1 | -32.0 -25.6 250 27 14 7.9 4.3
29000 -30.0 -22.0 270 26 13 7.5 4.1 | -29.7 -21.5 255 23 12 7.9 4.3
28000 -27.7 -17.9 275 24 13 7.0 3.9 | -27.3 -17.1 255 20 10 7.2 4.0
27000 -25.7 -14.3 275 25 13 6.8 3.8 | -25.2 -13.4 250 20 10 7.1 3.9
26000 -23.6 -10.5 270 26 13 6.8 3.8 | -23.1 -9.6 250 20 10 7.1 3.9
25000 -21.6 -6.9 270 27 14 6.9 3.8 | -21.0 -5.8 250 20 10 7.2 3.9
24000 -19.3 -2.7 265 27 14 7.7 4.2 | -18.8 -1.8 245 21 11 7.4 4.1
23000 -16.5 2.3 260 27 14 7.7 4.2 | -16.0 3.2 245 24 12 7.4 4.1
22000 -14.2 6.4 255 28 14 8.0 4.4 | -13.8 7.2 245 25 13 7.4 4.1
21000 -11.8 10.8 250 28 14 8.0 4.4 | -11.6 11.1 245 26 13 7.5 4.1
20000 -9.5 14.9 245 27 14 8.1 4.5 | -9.5 14.9 245 26 13 7.6 4.2
19500 -8.3 17.1 240 27 14 8.4 4.6 | -8.4 16.9 245 26 14 8.1 4.4
19000 -7.0 19.4 240 27 14 8.7 4.8 | -7.1 19.2 245 27 14 8.6 4.7
18500 -5.7 21.7 240 27 14 8.7 4.8 | -5.8 21.6 245 27 14 8.6 4.7
18000 -4.4 24.1 240 27 14 8.8 4.9 | -4.5 23.9 245 27 14 9.2 5.0
17500 -3.1 26.4 240 26 14 8.8 4.9 | -3.2 26.2 245 27 14 9.1 5.0
17000 -1.8 28.8 240 26 13 8.8 4.8 | -1.8 28.8 245 27 14 9.0 5.0
16500 -0.5 31.1 240 25 13 8.7 4.8 | -0.5 31.1 245 27 14 8.9 4.9
16000 0.8 33.4 245 24 13 8.7 4.7 | 0.8 33.4 245 27 14 8.9 4.9
15500 2.1 35.8 245 24 12 8.9 4.9 | 2.2 36.0 245 26 13 8.9 4.9
15000 3.4 38.1 245 23 12 8.9 4.9 | 3.5 38.3 245 25 13 8.9 4.9
14500 4.7 40.5 250 22 11 8.9 4.9 | 4.8 40.6 250 24 12 8.8 4.8
14000 6.0 42.8 250 21 11 8.9 4.9 | 6.1 43.0 250 23 12 8.8 4.8
13500 7.4 45.3 250 20 10 8.8 4.8 | 7.4 45.3 250 22 11 9.0 4.9
13000 8.7 47.7 250 19 10 8.8 4.8 | 8.8 47.8 250 20 11 9.1 5.0
12500 10.0 50.0 255 18 9 8.8 4.8 | 10.1 50.2 250 19 10 9.2 5.0
12000 11.3 52.3 255 17 9 9.7 4.9 | 11.5 52.7 250 18 9 9.3 5.1
11500 12.7 54.9 255 16 8 8.9 4.9 | 12.9 55.2 250 17 9 9.2 5.1
11000 14.0 57.2 255 15 8 8.4 4.6 | 14.3 57.7 250 16 8 9.0 4.9
10500 15.3 59.5 255 14 7 6.0 3.3 | 15.6 60.1 245 15 8 6.7 3.7
10250 15.6 60.1 255 14 7 6.3 3.5 | 16.1 61.0 250 15 8 7.3 4.0
10000 16.3 61.3 255 13 7 9.8 5.4 | 16.8 62.2 250 14 7 10.8 5.9
9750 17.0 62.6 255 12 6 9.1 5.0 | 17.6 63.7 250 13 7 10.1 5.5
9500 17.7 63.9 255 12 6 8.5 4.6 | 18.3 64.9 250 13 7 9.5 5.2
9250 18.2 64.8 255 12 6 6.5 3.6 | 19.0 66.2 250 12 6 8.7 4.7
9000 18.7 65.7 250 11 6 6.4 3.5 | 19.6 67.3 250 11 6 9.5 5.2
8750 19.2 66.6 250 10 5 7.0 3.9 | 20.4 68.7 250 11 5 10.1 5.5
8500 19.6 67.3 245 9 5 6.2 3.4 | 21.1 70.0 250 10 5 9.0 4.9
8250 20.4 68.7 240 8 4 5.0 2.7 | 21.7 71.1 250 9 5 6.5 3.5
8000 20.8 69.4 235 7 3 6.5 3.6 | 23.0 73.4 250 8 4 12.2 6.7
7750 21.2 70.2 220 6 3 4.9 2.7 | 23.9 75.0 250 7 4 9.7 5.3
7500 21.5 70.7 215 5 3 2.9 1.6 | 24.5 76.1 255 7 3 7.4 4.1
7250 21.7 71.1 210 4 2 4.1 2.2 | 25.1 77.2 260 6 3 9.0 4.9
7000 22.1 71.8 200 4 2 7.8 4.3 | 25.9 78.6 255 6 3 12.3 6.8
6750 22.7 72.9 185 4 2 8.1 4.4 | 26.8 80.2 250 6 3 11.5 6.3
6500 23.2 73.8 175 4 2 6.7 3.7 | 27.6 81.7 255 6 3 10.2 5.6
6250 23.7 74.7 160 3 2 6.5 3.6 | 28.3 82.9 260 5 3 9.3 5.1
6000 24.2 75.6 150 3 2 10.5 5.8 | 29.1 84.4 260 5 2 13.5 7.4
5750 25.4 77.7 150 3 2 20.2 11.1 | 30.6 87.1 260 5 2 28.2 15.4
5500 26.7 80.1 135 3 2 7.5 4.1 | 32.7 90.9 270 4 2 22.5 12.4
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
06/13/2024 at 1500 MDT | 06/13/2024 at 1800 MDT
|
CAPE... +20.2 LI... +0.1 | CAPE... +20.9 LI... -0.0
CINH... -6.9 K Index... +17.3 | CINH... -10.5 K Index... +17.6
|
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 -60.6 -77.1 245 40 21 2.7 1.5 | -60.5 -76.9 240 39 20 3.2 1.7
45000 -56.5 -69.7 245 58 30 2.8 1.5 | -56.1 -69.0 240 59 30 2.4 1.3
40000 -51.8 -61.2 245 61 31 5.5 3.0 | -52.2 -62.0 235 66 34 4.8 2.6
38000 -48.1 -54.6 240 53 27 5.6 3.0 | -48.9 -56.0 230 54 28 4.9 2.7
36000 -44.8 -48.6 240 46 24 6.0 3.3 | -46.0 -50.8 225 44 23 5.6 3.1
34000 -40.6 -41.1 240 39 20 7.0 3.9 | -41.3 -42.3 220 39 20 8.0 4.4
32000 -36.3 -33.3 235 33 17 7.1 3.9 | -36.6 -33.9 215 34 17 8.1 4.5
30000 -31.8 -25.2 235 24 13 7.7 4.2 | -31.9 -25.4 215 29 15 7.8 4.3
29000 -29.5 -21.1 235 20 10 7.7 4.2 | -29.5 -21.1 220 27 14 7.8 4.3
28000 -27.2 -17.0 235 17 9 7.2 4.0 | -27.2 -17.0 220 26 13 7.4 4.1
27000 -25.1 -13.2 225 18 9 7.1 3.9 | -25.0 -13.0 220 26 13 7.4 4.0
26000 -23.0 -9.4 220 19 10 7.2 3.9 | -22.9 -9.2 220 26 13 7.4 4.0
25000 -20.8 -5.4 210 21 11 7.1 3.9 | -20.7 -5.3 220 26 14 7.3 4.0
24000 -18.8 -1.8 215 23 12 6.8 3.7 | -18.6 -1.5 220 25 13 7.1 3.9
23000 -16.4 2.5 220 24 13 6.8 3.8 | -16.0 3.2 220 24 12 7.1 3.9
22000 -14.3 6.3 225 26 13 8.3 4.6 | -13.8 7.2 225 23 12 8.0 4.4
21000 -11.9 10.6 230 25 13 8.4 4.6 | -11.5 11.3 230 21 11 8.1 4.4
20000 -9.4 15.1 235 26 13 8.4 4.6 | -9.1 15.6 235 20 10 8.2 4.5
19500 -8.2 17.2 235 26 13 8.8 4.8 | -7.9 17.8 235 19 10 8.6 4.7
19000 -6.8 19.8 235 25 13 9.1 5.0 | -6.6 20.1 235 19 10 9.1 5.0
18500 -5.5 22.1 235 25 13 9.1 5.0 | -5.2 22.6 240 19 10 9.1 5.0
18000 -4.1 24.6 235 25 13 9.2 5.1 | -3.8 25.2 240 18 9 9.3 5.1
17500 -2.7 27.1 240 24 13 9.2 5.1 | -2.5 27.5 240 18 9 9.3 5.1
17000 -1.4 29.5 240 24 12 9.4 5.1 | -1.1 30.0 240 18 9 9.4 5.2
16500 0.0 32.0 240 24 12 9.5 5.2 | 0.3 32.5 240 18 9 9.6 5.2
16000 1.4 34.5 240 23 12 9.5 5.2 | 1.8 35.2 240 18 9 9.6 5.2
15500 2.9 37.2 240 23 12 9.5 5.2 | 3.2 37.8 240 18 9 9.4 5.1
15000 4.3 39.7 245 22 12 9.5 5.2 | 4.6 40.3 240 17 9 9.4 5.1
14500 5.7 42.3 245 22 11 9.5 5.2 | 6.0 42.8 240 17 9 9.7 5.3
14000 7.1 44.8 245 22 11 9.5 5.2 | 7.4 45.3 240 17 9 9.7 5.3
13500 8.5 47.3 245 21 11 9.5 5.2 | 8.9 48.0 240 17 9 9.6 5.3
13000 10.0 50.0 245 21 11 9.4 5.2 | 10.3 50.5 240 17 9 9.5 5.2
12500 11.4 52.5 250 20 10 9.5 5.2 | 11.7 53.1 240 16 8 9.5 5.2
12000 12.8 55.0 250 20 10 9.5 5.2 | 13.1 55.6 240 16 8 9.7 5.3
11500 14.2 57.6 250 19 10 9.3 5.1 | 14.6 58.3 240 16 8 9.5 5.2
11000 15.5 59.9 250 18 9 8.8 4.8 | 15.9 60.6 240 16 8 8.7 4.8
10500 16.8 62.2 250 17 9 10.7 5.9 | 17.2 63.0 240 15 8 11.0 6.0
10250 17.7 63.9 255 17 9 11.1 6.1 | 18.1 64.6 240 15 8 11.6 6.4
10000 18.4 65.1 255 16 8 8.8 4.8 | 18.9 66.0 240 15 8 9.0 4.9
9750 19.1 66.4 255 16 8 9.4 5.1 | 19.6 67.3 240 15 8 9.7 5.3
9500 19.8 67.6 255 15 8 9.5 5.2 | 20.3 68.5 240 14 7 9.5 5.2
9250 20.5 68.9 255 15 8 9.9 5.5 | 21.0 69.8 240 14 7 9.3 5.1
9000 21.3 70.3 260 15 8 9.8 5.4 | 21.7 71.1 240 14 7 9.3 5.1
8750 22.0 71.6 260 14 7 9.9 5.4 | 22.4 72.3 240 13 7 9.3 5.1
8500 22.8 73.0 260 14 7 9.5 5.2 | 23.7 74.7 240 13 7 8.6 4.7
8250 24.1 75.4 260 14 7 9.9 5.4 | 24.4 75.9 245 12 6 9.3 5.1
8000 24.9 76.8 260 14 7 11.9 6.5 | 25.1 77.2 240 12 6 10.4 5.7
7750 25.8 78.4 260 14 7 10.1 5.5 | 25.9 78.6 240 11 6 9.6 5.2
7500 26.4 79.5 265 14 7 7.8 4.3 | 26.5 79.7 240 11 6 8.2 4.5
7250 27.0 80.6 265 14 7 9.0 4.9 | 27.1 80.8 240 11 6 8.6 4.7
7000 27.8 82.0 265 13 7 11.9 6.5 | 27.9 82.2 240 11 5 10.2 5.6
6750 28.7 83.7 265 13 7 11.6 6.3 | 28.6 83.5 235 10 5 10.5 5.8
6500 29.5 85.1 265 13 7 10.7 5.9 | 29.4 84.9 240 9 5 10.4 5.7
6250 30.3 86.5 270 13 7 10.0 5.5 | 30.2 86.4 240 9 5 10.2 5.6
6000 31.1 88.0 270 13 6 12.4 6.8 | 30.9 87.6 240 9 5 9.3 5.1
5750 32.4 90.3 270 11 6 25.0 13.7 | 31.7 89.1 235 8 4 13.3 7.3
5500 34.8 94.6 275 11 6 38.2 21.0 | 33.4 92.1 240 7 4 37.5 20.6
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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