Soaring Guidance
Issued by NWS Grand Junction, CO
Issued by NWS Grand Junction, CO
176
UXUS97 KGJT 291307
SRGGJT
Soaring Forecast
National Weather Service Grand Junction, Colorado
707 AM MDT Wednesday, May 29, 2024
This forecast is for Wednesday, May 29, 2024:
If the trigger temperature of 80.1 F/26.7 C is reached...then
Thermal Soaring Index....................... Excellent
Maximum rate of lift........................ 1761 ft/min (8.9 m/s)
Maximum height of thermals.................. 22618 ft MSL (17779 ft AGL)
Forecast maximum temperature................... 90.0 F/32.7 C
Time of trigger temperature.................... 1045 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................. 13639 ft MSL (8799 ft AGL)
Thermal soaring outlook for Thursday 05/30..... Excellent
Wave Soaring Index............................. Not available
Remarks...
Sunrise/Sunset.................... 05:50:55 / 20:32:25 MDT
Total possible sunshine........... 14 hr 41 min 31 sec (881 min 31 sec)
Altitude of sun at 13:11:40 MDT... 72.49 degrees
Upper air data from rawinsonde observation taken on 05/29/2024 at 0600 MDT
Freezing level.................. 14451 ft MSL (9612 ft AGL)
Convective condensation level... 17818 ft MSL (12979 ft AGL)
Lifted condensation level....... 19155 ft MSL (14316 ft AGL)
Lifted index.................... -3.3
K index......................... +13.4
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 -56.8 -70.2 255 33 17 3.2 1.8 103.4 218.1 40.9 M M
45000 -56.4 -69.5 260 43 22 -1.5 -0.8 79.5 175.2 29.1 M M
40000 -59.1 -74.4 250 50 26 -1.4 -0.8 51.2 124.2 12.5 M M
38000 -56.6 -69.9 250 55 28 6.8 3.8 46.2 115.1 9.5 M M
36000 -52.4 -62.3 250 48 24 6.8 3.7 43.8 110.8 8.1 M M
34000 -47.9 -54.2 255 43 22 7.6 4.2 41.9 107.4 6.9 M M
32000 -42.9 -45.2 250 44 23 9.3 5.1 40.7 105.3 6.2 M M
30000 -37.6 -35.7 245 41 21 8.5 4.7 39.1 102.4 5.2 M M
29000 -34.9 -30.8 250 41 21 8.1 4.4 38.7 101.7 5.0 M M
28000 -32.7 -26.9 250 37 19 6.2 3.4 37.8 100.0 4.3 M M
27000 -30.9 -23.6 240 31 16 6.4 3.5 36.4 97.6 3.3 M M
26000 -28.6 -19.5 250 28 14 8.9 4.9 35.6 96.0 2.6 M M
25000 -26.4 -15.5 245 23 12 6.9 3.8 34.7 94.4 1.9 M M
24000 -24.3 -11.7 235 20 10 7.1 3.9 33.7 92.6 1.1 M M
23000 -22.2 -8.0 245 20 10 7.1 3.9 32.7 90.8 0.3 M M
22000 -19.9 -3.8 255 20 10 9.5 5.2 31.9 89.5 -0.3 1700 8.6
21000 -17.8 -0.0 250 21 11 5.6 3.1 31.0 87.8 -1.1 1607 8.2
20000 -16.2 2.8 240 17 9 8.2 4.5 29.6 85.3 -2.4 1528 7.8
19500 -14.7 5.5 245 16 8 9.7 5.3 29.6 85.3 -2.4 1470 7.5
19000 -13.3 8.1 235 16 8 9.4 5.2 29.6 85.3 -2.4 1412 7.2
18500 -11.9 10.6 245 12 6 9.3 5.1 29.5 85.1 -2.6 1357 6.9
18000 -10.6 12.9 240 14 7 9.2 5.1 29.4 85.0 -2.7 1301 6.6
17500 -9.2 15.4 245 15 8 9.8 5.4 29.4 84.9 -2.8 1244 6.3
17000 -7.8 18.0 255 16 8 9.0 4.9 29.3 84.8 -2.8 1188 6.0
16500 -5.6 21.9 250 15 8 9.6 5.3 29.3 84.8 -2.9 1102 5.6
16000 -4.2 24.4 255 15 8 9.6 5.3 29.3 84.8 -2.9 1044 5.3
15500 -2.8 27.0 255 16 8 9.6 5.3 29.3 84.8 -2.9 986 5.0
15000 -1.3 29.7 255 16 8 9.6 5.3 29.4 84.8 -2.9 929 4.7
14500 0.1 32.2 255 13 7 9.7 5.3 29.4 84.8 -2.9 871 4.4
14000 1.5 34.7 260 12 6 9.7 5.3 29.3 84.8 -3.0 813 4.1
13500 3.0 37.4 260 11 6 9.7 5.3 29.3 84.8 -3.0 755 3.8
13000 4.4 39.9 250 10 5 9.7 5.3 29.3 84.7 -3.1 697 3.5
12500 5.8 42.4 235 10 5 9.7 5.3 29.2 84.6 -3.1 639 3.2
12000 7.3 45.1 245 13 7 9.7 5.3 29.2 84.6 -3.2 581 3.0
11500 8.7 47.7 245 12 6 9.7 5.3 29.1 84.5 -3.3 524 2.7
11000 10.2 50.4 245 10 5 9.8 5.4 29.1 84.4 -3.3 466 2.4
10500 11.5 52.7 220 11 6 8.5 4.7 29.0 84.2 -3.5 410 2.1
10250 12.1 53.8 205 12 6 7.1 3.9 28.8 83.9 -3.6 385 2.0
10000 12.6 54.7 195 13 6 6.1 3.3 28.6 83.4 -3.9 364 1.8
9750 13.0 55.4 185 13 7 6.4 3.5 28.3 82.9 -4.2 343 1.7
9500 13.5 56.3 180 15 8 6.3 3.5 28.0 82.4 -4.5 322 1.6
9250 13.9 57.0 170 16 8 6.3 3.5 27.8 82.0 -4.8 301 1.5
9000 14.4 57.9 165 18 9 6.5 3.5 27.5 81.5 -5.0 280 1.4
8750 14.8 58.6 170 16 8 4.6 2.5 27.2 81.0 -5.4 259 1.3
8500 15.1 59.2 165 14 7 2.9 1.6 26.7 80.1 -5.9 245 1.2
8250 15.3 59.5 155 12 6 3.9 2.1 26.2 79.2 -6.4 231 1.2
8000 15.5 59.9 140 9 5 1.7 0.9 25.7 78.3 -6.9 217 1.1
7750 15.5 59.9 140 9 5 -0.1 -0.0 25.0 77.0 -7.7 210 1.1
7500 15.6 60.1 140 10 5 4.6 2.5 24.4 75.9 -8.3 198 1.0
7250 16.2 61.2 150 10 5 7.3 4.0 24.1 75.5 -8.5 176 0.9
7000 16.7 62.1 140 12 6 6.3 3.5 23.9 75.0 -8.7 153 0.8
6750 17.2 63.0 135 13 7 7.7 4.2 23.7 74.6 -9.0 131 0.7
6500 17.7 63.9 125 12 6 3.0 1.7 23.4 74.2 -9.2 108 0.5
6250 17.7 63.9 115 12 6 0.9 0.5 22.7 72.9 -10.0 101 0.5
6000 17.9 64.2 110 13 7 5.5 3.0 22.3 72.1 -10.5 86 0.4
5750 18.4 65.1 105 13 7 6.9 3.8 22.0 71.6 -10.8 65 0.3
5500 19.0 66.2 110 14 7 10.3 5.7 21.9 71.4 -10.9 40 0.2
5250 19.6 67.3 110 15 8 5.0 2.7 21.9 71.4 -11.1 14 0.1
5000 19.0 66.2 110 13 7 -23.8 -13.0 20.6 69.1 -12.5 25 0.1
* * * * * * Numerical weather prediction model forecast data valid * * * * * *
05/29/2024 at 0900 MDT | 05/29/2024 at 1200 MDT
|
CAPE... +5.9 LI... -0.3 | CAPE... +207.1 LI... -1.0
CINH... -23.9 K Index... +17.2 | CINH... -18.1 K Index... +19.8
|
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 -56.0 -68.8 265 26 14 0.2 0.1 | -55.7 -68.3 255 23 12 0.3 0.2
45000 -56.0 -68.8 255 34 17 -1.3 -0.7 | -55.6 -68.1 255 32 16 -1.8 -1.0
40000 -58.0 -72.4 250 38 19 -0.0 -0.0 | -58.5 -73.3 250 40 21 -0.6 -0.3
38000 -54.9 -66.8 250 39 20 5.6 3.1 | -55.0 -67.0 250 40 20 6.3 3.4
36000 -51.5 -60.7 255 40 21 5.6 3.1 | -51.2 -60.2 250 39 20 6.3 3.4
34000 -47.5 -53.5 255 41 21 7.4 4.0 | -47.1 -52.8 250 38 19 7.3 4.0
32000 -43.1 -45.6 250 41 21 7.4 4.0 | -42.8 -45.0 250 37 19 7.3 4.0
30000 -38.6 -37.5 250 39 20 7.6 4.2 | -38.5 -37.3 255 34 18 6.8 3.8
29000 -36.3 -33.3 255 36 19 7.6 4.2 | -36.5 -33.7 255 32 17 6.8 3.8
28000 -34.0 -29.2 255 34 17 7.6 4.2 | -34.4 -29.9 255 30 16 6.9 3.8
27000 -31.8 -25.2 255 31 16 7.3 4.0 | -32.3 -26.1 255 28 14 7.3 4.0
26000 -29.1 -20.4 255 27 14 7.3 4.0 | -29.5 -21.1 255 25 13 7.4 4.0
25000 -26.9 -16.4 255 24 13 7.3 4.0 | -27.3 -17.1 255 23 12 7.4 4.0
24000 -24.7 -12.5 255 23 12 7.2 4.0 | -25.1 -13.2 250 22 11 7.4 4.1
23000 -22.6 -8.7 250 21 11 7.2 4.0 | -22.9 -9.2 245 21 11 7.4 4.1
22000 -20.4 -4.7 250 20 10 7.2 3.9 | -20.7 -5.3 240 21 11 7.3 4.0
21000 -18.1 -0.6 245 20 10 8.0 4.4 | -18.3 -0.9 235 21 11 8.6 4.7
20000 -15.8 3.6 245 20 10 8.0 4.4 | -15.7 3.7 230 22 11 8.7 4.8
19500 -14.6 5.7 240 20 10 8.0 4.4 | -14.5 5.9 230 22 11 8.7 4.8
19000 -13.4 7.9 240 20 10 9.0 4.9 | -13.2 8.2 230 22 11 9.0 4.9
18500 -12.0 10.4 240 20 10 9.2 5.0 | -11.8 10.8 230 22 11 9.1 5.0
18000 -10.7 12.7 235 19 10 9.3 5.1 | -10.5 13.1 230 21 11 9.1 5.0
17500 -9.3 15.3 235 19 10 9.6 5.3 | -9.2 15.4 230 21 11 9.0 4.9
17000 -7.8 18.0 235 18 9 9.6 5.3 | -7.8 18.0 230 20 11 9.0 4.9
16500 -6.4 20.5 235 18 9 9.5 5.2 | -6.4 20.5 230 20 10 9.4 5.2
16000 -5.0 23.0 235 17 9 9.5 5.2 | -5.0 23.0 230 19 10 9.4 5.2
15500 -3.6 25.5 235 17 9 9.4 5.2 | -3.6 25.5 230 18 9 9.3 5.1
15000 -2.2 28.0 235 16 8 9.4 5.2 | -2.3 27.9 230 17 9 9.2 5.1
14500 -0.8 30.6 235 15 8 9.3 5.1 | -0.9 30.4 230 17 9 9.2 5.1
14000 0.6 33.1 235 14 7 9.1 5.0 | 0.5 32.9 230 16 8 9.4 5.1
13500 1.9 35.4 235 13 7 9.1 5.0 | 1.9 35.4 230 15 8 9.4 5.2
13000 3.2 37.8 230 12 6 8.8 4.8 | 3.2 37.8 230 14 7 9.0 4.9
12500 4.5 40.1 230 11 6 8.8 4.8 | 4.6 40.3 230 13 7 9.0 4.9
12000 5.8 42.4 230 10 5 8.6 4.7 | 5.9 42.6 225 13 7 9.2 5.0
11500 7.1 44.8 230 9 5 8.8 4.8 | 7.3 45.1 225 12 6 9.3 5.1
11000 8.3 46.9 230 9 5 7.2 4.0 | 8.6 47.5 230 11 6 8.0 4.4
10500 9.4 48.9 225 9 5 6.5 3.6 | 9.8 49.6 230 10 5 7.8 4.3
10250 9.9 49.8 225 9 5 10.2 5.6 | 10.4 50.7 230 10 5 10.5 5.8
10000 10.8 51.4 220 9 4 10.3 5.6 | 11.3 52.3 230 10 5 10.6 5.8
9750 11.4 52.5 215 9 4 6.7 3.7 | 11.9 53.4 230 10 5 8.4 4.6
9500 11.9 53.4 215 8 4 7.7 4.2 | 12.6 54.7 230 9 5 9.0 4.9
9250 12.5 54.5 210 8 4 7.2 3.9 | 13.2 55.8 230 9 4 8.8 4.8
9000 13.0 55.4 205 8 4 7.0 3.9 | 14.6 58.3 230 7 4 9.0 4.9
8750 14.0 57.2 195 8 4 7.2 3.9 | 15.2 59.4 230 7 4 9.3 5.1
8500 14.5 58.1 190 8 4 6.1 3.4 | 15.9 60.6 230 7 4 8.0 4.4
8250 15.0 59.0 190 8 4 5.5 3.0 | 16.5 61.7 235 6 3 8.8 4.8
8000 15.4 59.7 185 8 4 6.3 3.5 | 17.3 63.1 235 6 3 11.1 6.1
7750 15.8 60.4 180 8 4 5.8 3.2 | 18.1 64.6 230 6 3 10.7 5.9
7500 16.2 61.2 175 8 4 3.8 2.1 | 18.8 65.8 230 6 3 8.6 4.7
7250 16.4 61.5 170 8 4 3.2 1.8 | 19.4 66.9 235 5 3 8.1 4.5
7000 16.8 62.2 165 8 4 5.8 3.2 | 20.1 68.2 240 5 2 11.3 6.2
6750 17.2 63.0 165 7 4 7.0 3.8 | 21.0 69.8 230 5 3 11.9 6.5
6500 17.7 63.9 160 7 3 6.7 3.7 | 21.8 71.2 235 5 3 10.5 5.7
6250 18.2 64.8 155 6 3 6.2 3.4 | 22.6 72.7 240 4 2 10.4 5.7
6000 18.7 65.7 150 6 3 9.1 5.0 | 23.4 74.1 245 4 2 10.0 5.5
5750 19.7 67.5 150 5 2 18.5 10.1 | 24.3 75.7 235 4 2 18.2 10.0
5500 21.2 70.2 140 5 2 18.9 10.4 | 26.9 80.4 255 3 2 61.3 33.7
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
05/29/2024 at 1500 MDT | 05/29/2024 at 1800 MDT
|
CAPE... +109.6 LI... -0.2 | CAPE... +86.3 LI... -0.5
CINH... -5.0 K Index... +22.9 | CINH... -34.3 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 -56.3 -69.3 245 26 13 0.0 0.0 | -56.1 -69.0 250 30 15 0.2 0.1
45000 -56.5 -69.7 255 34 17 -1.2 -0.6 | -56.1 -69.0 255 36 19 -1.4 -0.8
40000 -58.4 -73.1 250 47 24 0.3 0.1 | -58.3 -72.9 250 51 26 -0.3 -0.2
38000 -55.0 -67.0 250 45 23 6.0 3.3 | -55.2 -67.4 250 47 24 5.7 3.1
36000 -51.4 -60.5 250 43 22 6.0 3.3 | -51.7 -61.1 255 43 22 5.7 3.1
34000 -47.3 -53.1 250 40 21 7.5 4.1 | -47.7 -53.9 255 39 20 7.4 4.1
32000 -42.8 -45.0 250 36 19 7.5 4.1 | -43.3 -45.9 255 34 17 7.4 4.1
30000 -38.3 -36.9 250 31 16 7.5 4.1 | -38.7 -37.7 255 29 15 8.0 4.4
29000 -36.1 -33.0 250 28 14 7.5 4.1 | -36.3 -33.3 255 26 14 8.0 4.4
28000 -33.8 -28.8 250 25 13 7.5 4.1 | -33.9 -29.0 255 24 12 8.0 4.4
27000 -31.6 -24.9 245 23 12 7.6 4.2 | -31.6 -24.9 255 22 11 7.1 3.9
26000 -28.7 -19.7 245 22 11 7.6 4.2 | -29.5 -21.1 250 21 11 7.1 3.9
25000 -26.5 -15.7 240 21 11 7.6 4.2 | -26.9 -16.4 240 20 10 7.1 3.9
24000 -24.2 -11.6 240 20 10 7.9 4.3 | -24.6 -12.3 240 20 10 8.0 4.4
23000 -21.8 -7.2 235 20 10 7.9 4.3 | -22.2 -8.0 235 21 11 8.1 4.4
22000 -19.5 -3.1 230 20 10 7.9 4.3 | -19.8 -3.6 235 21 11 8.1 4.4
21000 -17.2 1.0 230 19 10 7.9 4.3 | -17.4 0.7 235 22 11 8.5 4.7
20000 -14.8 5.4 225 19 10 8.0 4.4 | -14.9 5.2 235 22 11 8.5 4.7
19500 -13.7 7.3 225 18 9 8.0 4.4 | -13.6 7.5 235 22 11 8.5 4.7
19000 -12.5 9.5 225 18 9 8.1 4.4 | -12.3 9.9 235 22 12 8.9 4.9
18500 -11.3 11.7 225 18 9 8.1 4.5 | -11.0 12.2 235 22 12 9.0 5.0
18000 -10.1 13.8 225 17 9 8.2 4.5 | -9.7 14.5 235 22 11 9.1 5.0
17500 -8.9 16.0 230 17 9 8.4 4.6 | -8.3 17.1 235 22 11 9.5 5.2
17000 -7.6 18.3 230 17 9 8.4 4.6 | -6.8 19.8 235 22 11 9.5 5.2
16500 -6.4 20.5 230 17 9 8.6 4.7 | -5.4 22.3 235 22 11 9.6 5.3
16000 -5.1 22.8 230 16 8 8.6 4.7 | -4.0 24.8 240 22 11 9.6 5.3
15500 -3.8 25.2 230 16 8 8.7 4.8 | -2.5 27.5 240 21 11 9.5 5.2
15000 -2.5 27.5 230 16 8 8.9 4.9 | -1.1 30.0 240 21 11 9.5 5.2
14500 -1.2 29.8 230 16 8 9.0 4.9 | 0.3 32.5 240 21 11 9.5 5.2
14000 0.2 32.4 230 16 8 9.4 5.2 | 1.7 35.1 240 20 11 9.6 5.3
13500 1.6 34.9 235 16 8 9.4 5.2 | 3.2 37.8 240 20 10 9.7 5.3
13000 3.0 37.4 235 16 8 9.5 5.2 | 4.6 40.3 240 20 10 9.3 5.1
12500 4.4 39.9 235 16 8 9.4 5.2 | 6.0 42.8 240 20 10 9.3 5.1
12000 5.9 42.6 235 15 8 9.8 5.4 | 7.4 45.3 240 19 10 9.5 5.2
11500 7.3 45.1 240 15 8 9.9 5.4 | 8.8 47.8 240 19 10 9.6 5.3
11000 8.7 47.7 240 15 7 8.3 4.6 | 10.2 50.4 240 18 9 8.4 4.6
10500 9.9 49.8 240 14 7 8.6 4.7 | 11.4 52.5 240 18 9 8.6 4.7
10250 10.7 51.3 240 14 7 12.6 6.9 | 12.1 53.8 240 17 9 11.2 6.1
10000 11.7 53.1 240 14 7 12.1 6.6 | 13.0 55.4 240 17 9 10.8 5.9
9750 12.5 54.5 240 14 7 9.1 5.0 | 13.7 56.7 240 17 9 9.0 4.9
9500 13.2 55.8 240 14 7 10.2 5.6 | 14.4 57.9 240 17 9 9.7 5.3
9250 14.6 58.3 240 13 7 9.5 5.2 | 15.1 59.2 240 17 9 8.6 4.7
9000 15.4 59.7 240 13 7 10.7 5.9 | 16.4 61.5 240 16 8 9.7 5.3
8750 16.1 61.0 240 13 7 10.6 5.8 | 17.1 62.8 240 16 8 9.6 5.3
8500 16.9 62.4 240 13 7 9.8 5.4 | 17.8 64.0 240 15 8 9.1 5.0
8250 17.6 63.7 245 12 6 9.6 5.3 | 18.5 65.3 240 15 8 8.9 4.9
8000 18.4 65.1 245 12 6 10.4 5.7 | 19.2 66.6 240 15 8 9.1 5.0
7750 19.2 66.6 240 12 6 10.3 5.6 | 19.9 67.8 240 14 7 9.3 5.1
7500 19.9 67.8 240 12 6 9.0 4.9 | 20.5 68.9 240 13 7 8.4 4.6
7250 20.5 68.9 245 11 6 8.6 4.7 | 21.1 70.0 240 14 7 8.1 4.4
7000 21.3 70.3 245 11 6 10.9 6.0 | 21.8 71.2 240 13 7 9.6 5.2
6750 22.1 71.8 245 11 6 11.4 6.2 | 22.5 72.5 240 12 6 10.2 5.6
6500 22.9 73.2 245 11 5 10.3 5.6 | 23.3 73.9 240 12 6 10.6 5.8
6250 23.7 74.7 245 10 5 10.6 5.8 | 24.1 75.4 240 12 6 11.5 6.3
6000 24.4 75.9 250 10 5 8.1 4.4 | 24.9 76.8 240 12 6 7.8 4.3
5750 25.1 77.2 240 9 5 11.8 6.4 | 25.4 77.7 240 10 5 8.0 4.4
5500 27.4 81.3 255 8 4 66.8 36.6 | 27.3 81.1 240 9 5 58.2 32.0
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
________________________________________________________________________________
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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