Soaring Guidance
Issued by NWS Grand Junction, CO
Issued by NWS Grand Junction, CO
243
UXUS97 KGJT 011307
SRGGJT
Soaring Forecast
National Weather Service Grand Junction, Colorado
707 AM MDT Saturday, June 1, 2024
This forecast is for Saturday, June 1, 2024:
If the trigger temperature of 77.6 F/25.3 C is reached...then
Thermal Soaring Index....................... Excellent
Maximum rate of lift........................ 1777 ft/min (9.0 m/s)
Maximum height of thermals.................. 23194 ft MSL (18355 ft AGL)
Forecast maximum temperature................... 91.0 F/33.2 C
Time of trigger temperature.................... 1000 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................. 18740 ft MSL (13901 ft AGL)
Thermal soaring outlook for Sunday 06/02....... Excellent
Wave Soaring Index............................. Not available
Remarks...
Sunrise/Sunset.................... 05:49:40 / 20:34:34 MDT
Total possible sunshine........... 14 hr 44 min 53 sec (884 min 53 sec)
Altitude of sun at 13:12:07 MDT... 72.88 degrees
Upper air data from rawinsonde observation taken on 06/01/2024 at 0600 MDT
Freezing level.................. 14160 ft MSL (9321 ft AGL)
Convective condensation level... 17064 ft MSL (12225 ft AGL)
Lifted condensation level....... 18697 ft MSL (13858 ft AGL)
Lifted index.................... -4.4
K index......................... +17.4
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 -58.4 -73.1 255 37 19 1.0 0.6 101.7 215.1 39.5 M M
45000 -58.2 -72.8 280 39 20 -3.4 -1.9 76.2 169.2 26.7 M M
40000 -61.4 -78.5 280 44 23 3.1 1.7 48.1 118.6 10.1 M M
38000 -56.8 -70.2 285 40 20 8.4 4.6 46.3 115.3 9.2 M M
36000 -52.2 -62.0 280 35 18 7.0 3.9 44.4 112.0 8.1 M M
34000 -47.7 -53.9 280 30 15 8.8 4.8 42.5 108.5 7.0 M M
32000 -41.8 -43.2 270 30 15 8.8 4.8 41.6 106.8 6.5 M M
30000 -37.2 -35.0 255 28 14 7.4 4.1 39.9 103.8 5.4 M M
29000 -34.9 -30.8 265 24 12 8.6 4.7 39.0 102.3 4.8 M M
28000 -32.3 -26.1 265 25 13 8.8 4.8 38.7 101.6 4.5 M M
27000 -30.6 -23.1 260 27 14 2.2 1.2 37.0 98.6 3.3 M M
26000 -29.7 -21.5 260 32 16 7.5 4.1 34.5 94.0 1.3 M M
25000 -26.9 -16.4 260 31 16 9.5 5.2 34.3 93.8 1.2 M M
24000 -24.6 -12.3 260 32 16 6.5 3.6 33.5 92.4 0.6 M M
23000 -22.3 -8.1 270 30 15 8.3 4.5 32.8 91.0 -0.1 1761 8.9
22000 -20.0 -4.0 260 29 15 7.2 4.0 32.1 89.8 -0.6 1661 8.4
21000 -18.6 -1.5 265 36 18 7.3 4.0 30.4 86.7 -2.1 1588 8.1
20000 -16.0 3.2 260 36 19 9.3 5.1 30.0 86.0 -2.6 1484 7.5
19500 -14.7 5.5 260 36 19 9.2 5.1 29.9 85.9 -2.7 1428 7.3
19000 -13.3 8.1 265 36 19 8.9 4.9 29.9 85.7 -2.8 1372 7.0
18500 -12.1 10.2 265 33 17 8.2 4.5 29.6 85.3 -3.1 1322 6.7
18000 -10.8 12.6 270 32 16 9.5 5.2 29.5 85.0 -3.2 1267 6.4
17500 -8.6 16.5 275 31 16 9.4 5.2 29.4 84.9 -3.3 1180 6.0
17000 -7.2 19.0 275 29 15 9.4 5.1 29.3 84.8 -3.4 1123 5.7
16500 -5.9 21.4 270 24 12 8.5 4.7 29.2 84.5 -3.5 1069 5.4
16000 -4.6 23.7 275 24 12 8.9 4.9 29.0 84.2 -3.7 1016 5.2
15500 -3.3 26.1 275 23 12 8.8 4.8 28.8 83.9 -3.9 962 4.9
15000 -2.0 28.4 280 22 12 8.8 4.8 28.7 83.7 -4.1 908 4.6
14500 -0.7 30.7 285 22 11 8.7 4.8 28.5 83.4 -4.2 854 4.3
14000 0.6 33.1 290 17 9 8.7 4.8 28.4 83.1 -4.4 800 4.1
13500 1.9 35.4 290 11 6 8.7 4.8 28.2 82.8 -4.6 746 3.8
13000 3.2 37.8 320 9 5 8.7 4.8 28.1 82.5 -4.8 692 3.5
12500 4.5 40.1 285 8 4 8.8 4.8 27.9 82.2 -5.0 638 3.2
12000 5.8 42.4 280 5 3 8.8 4.8 27.7 81.9 -5.2 584 3.0
11500 7.0 44.6 275 3 1 7.5 4.1 27.5 81.4 -5.4 532 2.7
11000 8.1 46.6 240 2 1 7.0 3.8 27.0 80.7 -5.9 487 2.5
10500 9.3 48.7 150 6 3 10.2 5.6 26.8 80.3 -6.2 436 2.2
10250 10.0 50.0 145 6 3 9.2 5.1 26.9 80.3 -6.2 407 2.1
10000 10.7 51.3 115 4 2 8.6 4.7 26.8 80.2 -6.3 379 1.9
9750 11.3 52.3 125 4 2 8.7 4.8 26.7 80.1 -6.4 352 1.8
9500 12.0 53.6 150 4 2 9.0 4.9 26.6 79.9 -6.4 325 1.6
9250 12.6 54.7 150 6 3 6.8 3.8 26.5 79.7 -6.6 298 1.5
9000 13.0 55.4 145 8 4 5.0 2.7 26.2 79.1 -6.9 279 1.4
8750 13.4 56.1 145 9 4 5.5 3.0 25.8 78.5 -7.3 260 1.3
8500 13.8 56.8 150 11 6 5.4 3.2 25.5 77.9 -7.6 241 1.2
8250 14.2 57.6 150 14 7 5.4 3.0 25.2 77.3 -8.0 222 1.1
8000 14.6 58.3 150 18 9 5.4 3.0 24.8 76.7 -8.3 203 1.0
7750 15.0 59.0 150 19 10 5.4 3.0 24.5 76.1 -8.7 184 0.9
7500 15.4 59.7 155 19 10 5.4 3.0 24.2 75.5 -9.1 165 0.8
7250 15.7 60.3 150 19 10 5.5 3.0 23.8 74.9 -9.4 146 0.7
7000 16.1 61.0 140 16 8 5.0 2.8 23.5 74.3 -9.8 127 0.6
6750 16.4 61.5 130 14 7 2.6 1.4 23.1 73.5 -10.3 112 0.6
6500 16.4 61.5 120 12 6 -2.3 -1.3 22.4 72.2 -11.0 104 0.5
6250 16.2 61.2 110 11 6 0.8 0.4 21.4 70.6 -12.0 102 0.5
6000 16.6 61.9 120 9 5 5.7 3.1 21.0 69.9 -12.4 85 0.4
5750 16.9 62.4 135 10 5 3.8 2.1 20.6 69.2 -12.8 68 0.3
5500 17.2 63.0 150 13 7 6.3 3.4 20.3 68.5 -13.3 50 0.3
5250 17.7 63.9 145 13 7 3.3 1.8 20.0 68.0 -13.6 30 0.2
5000 17.3 63.1 145 13 7 -15.3 -8.4 18.9 66.0 -14.7 34 0.2
* * * * * * Numerical weather prediction model forecast data valid * * * * * *
06/01/2024 at 0900 MDT | 06/01/2024 at 1200 MDT
|
CAPE... +5.5 LI... +0.1 | CAPE... +177.8 LI... -1.1
CINH... -27.9 K Index... +18.4 | CINH... -15.0 K Index... +20.5
|
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 -57.4 -71.3 270 31 16 0.0 0.0 | -58.3 -72.9 265 34 17 -0.1 -0.1
45000 -57.6 -71.7 275 41 21 -1.3 -0.7 | -58.4 -73.1 270 43 22 -0.0 -0.0
40000 -59.6 -75.3 275 53 27 -2.1 -1.2 | -58.5 -73.3 275 55 28 -0.8 -0.4
38000 -56.2 -69.2 270 51 26 7.1 3.9 | -54.5 -66.1 275 53 27 6.7 3.7
36000 -51.4 -60.5 265 47 24 7.1 3.9 | -50.6 -59.1 275 50 26 6.7 3.6
34000 -46.9 -52.4 260 45 23 7.9 4.4 | -46.3 -51.3 270 47 24 7.5 4.1
32000 -42.1 -43.8 260 42 22 7.9 4.4 | -41.8 -43.2 270 46 23 7.5 4.1
30000 -37.7 -35.9 260 40 20 7.0 3.8 | -37.6 -35.7 265 43 22 6.6 3.6
29000 -35.6 -32.1 260 38 20 7.0 3.8 | -35.6 -32.1 265 42 22 6.6 3.6
28000 -33.5 -28.3 260 37 19 7.0 3.8 | -33.6 -28.5 260 42 21 6.7 3.6
27000 -31.4 -24.5 260 37 19 7.2 4.0 | -31.4 -24.5 260 41 21 7.8 4.3
26000 -29.2 -20.6 260 37 19 7.2 4.0 | -29.1 -20.4 260 40 20 7.8 4.3
25000 -27.1 -16.8 260 37 19 7.2 4.0 | -26.7 -16.1 260 39 20 7.8 4.3
24000 -24.9 -12.8 260 37 19 7.2 4.0 | -24.5 -12.1 260 38 19 6.6 3.6
23000 -22.8 -9.0 260 36 18 7.2 4.0 | -22.0 -7.6 255 36 19 6.7 3.7
22000 -20.1 -4.2 255 35 18 7.2 3.9 | -20.0 -4.0 255 35 18 6.6 3.6
21000 -17.9 -0.2 255 33 17 7.6 4.2 | -17.8 -0.0 255 34 17 8.0 4.4
20000 -15.7 3.7 255 31 16 7.7 4.2 | -15.4 4.3 250 32 16 8.0 4.4
19500 -14.5 5.9 255 30 16 7.7 4.2 | -14.3 6.3 250 31 16 8.0 4.4
19000 -13.4 7.9 255 29 15 8.3 4.6 | -13.1 8.4 250 30 16 8.8 4.8
18500 -12.2 10.0 255 28 14 8.5 4.7 | -11.7 10.9 245 29 15 9.0 4.9
18000 -10.9 12.4 260 26 13 8.6 4.7 | -10.4 13.3 245 28 15 9.0 5.0
17500 -9.6 14.7 260 24 12 8.8 4.8 | -9.1 15.6 245 27 14 9.2 5.0
17000 -8.3 17.1 265 22 11 8.8 4.8 | -7.7 18.1 245 26 13 9.2 5.0
16500 -7.0 19.4 265 20 10 9.2 5.0 | -6.4 20.5 245 24 12 9.0 4.9
16000 -5.6 21.9 265 19 10 9.2 5.1 | -5.1 22.8 240 22 11 9.0 4.9
15500 -4.3 24.3 270 17 9 9.2 5.0 | -3.8 25.2 240 20 10 9.1 5.0
15000 -2.9 26.8 270 16 8 9.1 5.0 | -2.4 27.7 240 18 9 9.2 5.0
14500 -1.6 29.1 270 15 7 9.1 5.0 | -1.0 30.2 235 17 9 9.2 5.1
14000 -0.2 31.6 265 13 7 9.3 5.1 | 0.4 32.7 235 16 8 9.3 5.1
13500 1.2 34.2 260 12 6 9.3 5.1 | 1.7 35.1 235 15 8 9.3 5.1
13000 2.6 36.7 255 11 6 9.0 4.9 | 3.1 37.6 230 14 7 9.5 5.2
12500 3.9 39.0 250 10 5 9.0 5.0 | 4.6 40.3 230 13 7 9.5 5.2
12000 5.2 41.4 240 9 5 8.7 4.7 | 5.9 42.6 225 12 6 9.2 5.1
11500 6.5 43.7 230 9 4 8.7 4.8 | 7.3 45.1 225 12 6 9.4 5.1
11000 7.7 45.9 220 8 4 7.5 4.1 | 8.6 47.5 220 11 6 7.5 4.1
10500 8.8 47.8 210 8 4 6.8 3.7 | 9.7 49.5 220 10 5 7.6 4.2
10250 9.4 48.9 210 8 4 10.0 5.5 | 10.4 50.7 220 9 5 11.9 6.5
10000 10.2 50.4 200 8 4 9.9 5.4 | 11.3 52.3 215 9 5 11.5 6.3
9750 10.8 51.4 195 9 4 6.7 3.7 | 12.0 53.6 215 9 4 8.2 4.5
9500 11.3 52.3 190 9 5 7.4 4.1 | 12.7 54.9 210 8 4 9.6 5.3
9250 11.8 53.2 185 9 5 7.7 4.2 | 13.3 55.9 210 8 4 7.3 4.0
9000 12.4 54.3 180 10 5 7.6 4.2 | 13.8 56.8 210 7 3 8.0 4.4
8750 12.9 55.2 180 10 5 6.9 3.8 | 14.5 58.1 205 6 3 10.4 5.7
8500 13.4 56.1 175 10 5 7.2 4.0 | 16.0 60.8 200 6 3 8.9 4.9
8250 14.4 57.9 165 12 6 5.6 3.1 | 16.6 61.9 195 5 3 9.0 4.9
8000 14.8 58.6 165 12 6 5.5 3.0 | 17.4 63.3 195 5 3 10.7 5.8
7750 15.2 59.4 160 11 5 5.3 2.9 | 18.2 64.8 195 5 3 10.6 5.8
7500 15.5 59.9 155 10 5 4.0 2.2 | 18.9 66.0 195 5 3 8.7 4.8
7250 15.7 60.3 155 11 6 3.5 1.9 | 19.5 67.1 190 4 2 8.1 4.4
7000 16.1 61.0 150 11 5 6.8 3.8 | 20.2 68.4 190 4 2 11.2 6.1
6750 16.7 62.1 150 9 4 8.0 4.4 | 21.1 70.0 190 4 2 11.9 6.5
6500 17.2 63.0 145 8 4 6.7 3.7 | 21.9 71.4 190 4 2 10.5 5.7
6250 17.7 63.9 145 8 4 6.4 3.5 | 22.7 72.9 185 4 2 10.7 5.9
6000 18.2 64.8 140 8 4 8.3 4.6 | 23.5 74.3 180 3 2 8.3 4.6
5750 19.1 66.4 135 6 3 16.7 9.2 | 24.1 75.4 190 4 2 13.8 7.5
5500 20.8 69.4 135 6 3 30.7 16.8 | 27.0 80.6 175 3 1 80.5 44.1
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
06/01/2024 at 1500 MDT | 06/01/2024 at 1800 MDT
|
CAPE... +115.9 LI... -0.2 | CAPE... +71.2 LI... -0.2
CINH... -17.0 K Index... +22.5 | CINH... -31.8 K Index... +22.5
|
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 -58.6 -73.5 260 36 19 -0.2 -0.1 | -58.5 -73.3 260 38 20 -0.1 -0.0
45000 -58.8 -73.8 265 44 23 0.4 0.2 | -58.5 -73.3 260 48 25 0.3 0.1
40000 -58.2 -72.8 265 64 33 3.6 2.0 | -58.1 -72.6 255 72 37 3.2 1.7
38000 -54.2 -65.6 265 60 31 6.6 3.6 | -54.4 -65.9 255 68 35 6.1 3.4
36000 -50.2 -58.4 270 57 29 6.6 3.6 | -50.7 -59.3 260 63 33 6.1 3.4
34000 -45.8 -50.4 270 54 28 7.8 4.3 | -46.4 -51.5 255 58 30 7.9 4.3
32000 -41.2 -42.2 270 51 26 7.8 4.3 | -41.7 -43.1 255 51 26 7.9 4.3
30000 -36.9 -34.4 270 47 24 6.6 3.6 | -37.1 -34.8 255 46 23 7.4 4.1
29000 -34.9 -30.8 265 45 23 6.6 3.6 | -34.9 -30.8 250 43 22 7.4 4.1
28000 -32.9 -27.2 260 44 23 6.6 3.6 | -32.7 -26.9 250 41 21 7.4 4.1
27000 -30.8 -23.4 260 42 21 7.7 4.2 | -30.4 -22.7 245 38 20 7.7 4.2
26000 -28.5 -19.3 255 39 20 7.7 4.2 | -28.1 -18.6 245 35 18 7.7 4.2
25000 -26.2 -15.2 255 37 19 7.7 4.2 | -25.8 -14.4 240 33 17 7.8 4.3
24000 -23.3 -9.9 250 34 17 7.8 4.3 | -22.9 -9.2 240 30 15 8.2 4.5
23000 -21.0 -5.8 245 31 16 7.8 4.3 | -20.5 -4.9 235 27 14 8.2 4.5
22000 -18.7 -1.7 240 29 15 7.9 4.3 | -18.1 -0.6 235 25 13 8.4 4.6
21000 -16.3 2.7 235 26 14 8.0 4.4 | -15.7 3.7 235 23 12 7.8 4.3
20000 -14.0 6.8 230 24 12 8.0 4.4 | -13.4 7.9 235 22 11 7.9 4.3
19500 -12.8 9.0 230 23 12 8.1 4.4 | -12.3 9.9 235 21 11 7.9 4.3
19000 -11.6 11.1 230 22 11 8.3 4.6 | -11.2 11.8 235 20 10 8.0 4.4
18500 -10.4 13.3 230 21 11 8.4 4.6 | -10.0 14.0 235 20 10 8.0 4.4
18000 -9.2 15.4 230 20 10 8.4 4.6 | -8.8 16.2 235 19 10 8.1 4.4
17500 -8.0 17.6 230 19 10 8.3 4.6 | -7.5 18.5 235 19 10 8.8 4.8
17000 -6.7 19.9 230 19 10 8.3 4.5 | -6.2 20.8 235 19 10 8.7 4.8
16500 -5.5 22.1 230 18 9 8.8 4.9 | -4.9 23.2 235 18 9 9.2 5.1
16000 -4.1 24.6 230 17 9 8.9 4.9 | -3.5 25.7 235 18 9 9.3 5.1
15500 -2.8 27.0 230 17 9 9.1 5.0 | -2.1 28.2 235 18 9 9.4 5.2
15000 -1.4 29.5 230 16 8 9.4 5.2 | -0.7 30.7 235 17 9 9.5 5.2
14500 -0.0 32.0 230 16 8 9.4 5.2 | 0.8 33.4 235 17 9 9.6 5.2
14000 1.4 34.5 230 15 8 9.5 5.2 | 2.2 36.0 235 17 9 9.6 5.3
13500 2.8 37.0 230 15 8 9.5 5.2 | 3.6 38.5 235 16 8 9.6 5.3
13000 4.2 39.6 230 14 7 9.3 5.1 | 5.1 41.2 235 16 8 9.4 5.2
12500 5.6 42.1 235 14 7 9.3 5.1 | 6.5 43.7 235 15 8 9.4 5.2
12000 7.0 44.6 235 13 7 9.6 5.3 | 7.9 46.2 235 15 8 9.4 5.1
11500 8.5 47.3 235 13 7 9.7 5.3 | 9.3 48.7 235 14 7 9.4 5.2
11000 9.9 49.8 235 12 6 8.4 4.6 | 10.7 51.3 235 14 7 8.8 4.8
10500 11.1 52.0 235 11 5 8.7 4.8 | 11.9 53.4 235 13 6 9.0 4.9
10250 11.8 53.2 235 11 5 11.8 6.5 | 12.7 54.9 235 13 6 11.0 6.1
10000 12.7 54.9 235 11 6 11.2 6.2 | 13.5 56.3 235 13 7 10.6 5.8
9750 13.5 56.3 235 11 6 9.2 5.1 | 14.2 57.6 235 12 6 9.2 5.0
9500 14.2 57.6 235 11 6 9.9 5.4 | 14.9 58.8 235 12 6 9.5 5.2
9250 14.9 58.8 240 11 6 9.1 5.0 | 15.6 60.1 235 11 6 9.5 5.2
9000 16.3 61.3 240 10 5 10.3 5.7 | 16.4 61.5 230 12 6 9.5 5.2
8750 17.1 62.8 240 10 5 10.3 5.7 | 17.8 64.0 230 12 6 9.4 5.2
8500 17.8 64.0 240 10 5 9.5 5.2 | 18.5 65.3 230 11 6 9.4 5.2
8250 18.5 65.3 250 9 5 9.5 5.2 | 19.2 66.6 235 10 5 9.5 5.2
8000 19.3 66.7 245 9 5 10.3 5.6 | 19.9 67.8 230 10 5 9.3 5.1
7750 20.0 68.0 245 9 5 10.4 5.7 | 20.6 69.1 230 10 5 9.5 5.2
7500 20.8 69.4 245 9 5 9.3 5.1 | 21.3 70.3 230 10 5 8.8 4.8
7250 21.5 70.7 250 9 5 8.7 4.8 | 21.9 71.4 230 10 5 8.4 4.6
7000 22.2 72.0 250 9 4 10.4 5.7 | 22.6 72.7 230 9 5 9.5 5.2
6750 23.0 73.4 250 9 5 11.0 6.0 | 23.3 73.9 230 9 5 9.8 5.4
6500 23.8 74.8 250 9 4 10.9 6.0 | 24.0 75.2 225 9 5 10.4 5.7
6250 24.6 76.3 255 8 4 11.7 6.4 | 24.9 76.8 230 9 5 11.5 6.3
6000 25.4 77.7 255 8 4 8.0 4.4 | 25.6 78.1 230 8 4 8.2 4.5
5750 26.0 78.8 250 8 4 11.9 6.5 | 26.2 79.2 225 8 4 8.6 4.7
5500 28.9 84.0 260 7 4 83.7 45.9 | 27.9 82.2 230 7 4 51.2 28.1
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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