Soaring Guidance
Issued by NWS Grand Junction, CO
Issued by NWS Grand Junction, CO
464
UXUS97 KGJT 021307
SRGGJT
Soaring Forecast
National Weather Service Grand Junction, Colorado
707 AM MDT Sunday, June 2, 2024
This forecast is for Sunday, June 2, 2024:
If the trigger temperature of 82.1 F/27.9 C is reached...then
Thermal Soaring Index....................... Excellent
Maximum rate of lift........................ 1459 ft/min (7.4 m/s)
Maximum height of thermals.................. 21512 ft MSL (16673 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....... Broken/overcast thin middle
Surface winds during soaring window............ 20 mph or less
Height of the -3 thermal index................. 13888 ft MSL (9048 ft AGL)
Thermal soaring outlook for Monday 06/03....... Excellent
Wave Soaring Index............................. Not available
Remarks...
Sunrise/Sunset.................... 05:49:19 / 20:35:14 MDT
Total possible sunshine........... 14 hr 45 min 55 sec (885 min 55 sec)
Altitude of sun at 13:12:17 MDT... 73.00 degrees
Upper air data from rawinsonde observation taken on 06/02/2024 at 0600 MDT
Freezing level.................. 14557 ft MSL (9718 ft AGL)
Convective condensation level... 19927 ft MSL (15088 ft AGL)
Lifted condensation level....... 20733 ft MSL (15894 ft AGL)
Lifted index.................... -0.2
K index......................... +8.5
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 -57.9 -72.2 255 29 15 2.0 1.1 100.7 213.3 39.4 M M
45000 -55.3 -67.5 250 37 19 5.9 3.2 80.6 177.0 29.8 M M
40000 -57.4 -71.3 240 54 28 6.8 3.7 53.2 127.8 13.9 M M
38000 -55.6 -68.1 245 55 28 4.9 2.7 47.2 117.0 10.2 M M
36000 -51.2 -60.2 250 56 29 8.1 4.5 45.2 113.4 9.1 M M
34000 -46.8 -52.2 245 59 30 7.3 4.0 43.1 109.5 7.8 M M
32000 -42.4 -44.3 250 52 27 7.1 3.9 41.1 106.0 6.5 M M
30000 -37.0 -34.6 245 51 26 8.3 4.6 39.6 103.3 5.6 M M
29000 -34.5 -30.1 245 51 26 8.3 4.6 39.0 102.3 5.2 M M
28000 -32.0 -25.6 245 48 25 8.9 4.9 38.5 101.3 4.9 M M
27000 -29.3 -20.7 245 47 24 7.9 4.3 38.2 100.7 4.6 M M
26000 -27.1 -16.8 255 43 22 7.9 4.4 37.2 99.0 4.0 M M
25000 -24.8 -12.6 250 45 23 7.9 4.3 36.5 97.7 3.4 M M
24000 -22.6 -8.7 240 43 22 7.0 3.8 35.6 96.2 2.8 M M
23000 -20.7 -5.3 250 46 24 5.9 3.2 34.3 93.7 1.7 M M
22000 -19.0 -2.2 235 41 21 6.7 3.7 32.9 91.2 0.5 M M
21000 -17.2 1.0 235 36 18 5.5 3.0 31.5 88.8 -0.6 1623 8.2
20000 -15.1 4.8 230 36 18 8.9 4.9 30.7 87.2 -1.5 1530 7.8
19500 -13.7 7.3 225 35 18 9.2 5.0 30.6 87.1 -1.5 1473 7.5
19000 -12.3 9.9 220 36 19 8.4 4.6 30.5 86.9 -1.7 1418 7.2
18500 -11.1 12.0 215 33 17 9.4 5.2 30.3 86.6 -1.8 1365 6.9
18000 -9.7 14.5 220 31 16 9.2 5.1 30.2 86.4 -2.0 1309 6.6
17500 -8.4 16.9 220 29 15 8.9 4.9 30.1 86.2 -2.1 1255 6.4
17000 -7.1 19.2 220 27 14 8.9 4.9 30.0 85.9 -2.3 1201 6.1
16500 -5.1 22.8 230 24 13 9.2 5.0 29.8 85.6 -2.5 1119 5.7
16000 -3.7 25.3 240 24 12 9.2 5.1 29.7 85.4 -2.6 1064 5.4
15500 -2.4 27.7 235 21 11 9.2 5.1 29.6 85.3 -2.7 1008 5.1
15000 -1.0 30.2 235 21 11 9.2 5.1 29.5 85.1 -2.8 952 4.8
14500 0.4 32.7 240 23 12 9.2 5.1 29.4 84.9 -2.9 896 4.6
14000 1.8 35.2 245 26 13 9.2 5.1 29.3 84.8 -3.0 840 4.3
13500 3.2 37.8 245 28 15 9.3 5.1 29.3 84.7 -3.1 784 4.0
13000 4.5 40.1 250 31 16 9.3 5.1 29.2 84.6 -3.1 727 3.7
12500 5.9 42.6 255 30 15 9.3 5.1 29.1 84.4 -3.2 671 3.4
12000 7.3 45.1 260 26 13 9.3 5.1 29.1 84.3 -3.3 615 3.1
11500 8.7 47.7 260 24 13 9.3 5.1 29.0 84.1 -3.4 558 2.8
11000 10.1 50.2 260 23 12 9.3 5.1 28.9 84.0 -3.5 502 2.6
10500 11.5 52.7 260 24 12 9.3 5.1 28.8 83.8 -3.6 446 2.3
10250 12.2 54.0 260 22 11 9.1 5.0 28.8 83.8 -3.6 418 2.1
10000 12.8 55.0 260 22 11 8.7 4.8 28.7 83.6 -3.7 390 2.0
9750 13.5 56.3 260 22 12 8.6 4.7 28.6 83.5 -3.8 364 1.8
9500 14.1 57.4 260 23 12 8.7 4.8 28.5 83.3 -3.9 337 1.7
9250 14.7 58.5 260 23 12 8.6 4.7 28.4 83.2 -4.0 311 1.6
9000 15.4 59.7 260 25 13 8.8 4.8 28.3 83.0 -4.1 284 1.4
8750 16.0 60.8 255 26 13 8.0 4.4 28.2 82.8 -4.2 258 1.3
8500 16.6 61.9 255 26 14 6.9 3.8 28.0 82.5 -4.4 234 1.2
8250 17.1 62.8 250 25 13 6.8 3.7 27.8 82.1 -4.7 212 1.1
8000 17.6 63.7 260 19 10 6.8 3.7 27.6 81.7 -4.9 189 1.0
7750 18.1 64.6 265 17 9 6.8 3.7 27.4 81.2 -5.1 167 0.8
7500 18.6 65.5 260 15 8 6.8 3.7 27.1 80.8 -5.4 144 0.7
7250 19.1 66.4 255 13 6 6.8 3.7 26.9 80.4 -5.6 122 0.6
7000 19.6 67.3 250 10 5 6.8 3.7 26.7 80.0 -5.9 100 0.5
6750 20.1 68.2 240 11 5 6.8 3.7 26.4 79.6 -6.1 77 0.4
6500 20.6 69.1 230 10 5 6.9 3.8 26.2 79.2 -6.4 55 0.3
6250 21.1 70.0 215 9 5 6.2 3.4 26.0 78.7 -6.6 33 0.2
6000 21.5 70.7 200 4 2 8.5 4.6 25.7 78.3 -6.9 11 0.1
5750 22.0 71.6 170 4 2 -0.2 -0.1 25.5 77.9 -7.2 M M
5500 21.2 70.2 140 6 3 -19.5 -10.7 24.0 75.1 -8.8 7 0.0
5250 19.3 66.7 125 7 4 -25.9 -14.2 21.4 70.5 -11.4 56 0.3
5000 17.5 63.5 115 4 2 -21.7 -11.9 18.8 65.9 -14.0 104 0.5
* * * * * * Numerical weather prediction model forecast data valid * * * * * *
06/02/2024 at 0900 MDT | 06/02/2024 at 1200 MDT
|
CAPE... 0.0 LI... +1.9 | CAPE... +11.9 LI... +0.7
CINH... 0.0 K Index... +10.5 | CINH... -3.5 K Index... +13.4
|
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 -69.3 260 35 18 0.4 0.2 | -56.5 -69.7 265 32 17 0.7 0.4
45000 -55.9 -68.6 255 37 19 -0.7 -0.4 | -55.8 -68.4 260 36 19 -0.8 -0.4
40000 -56.9 -70.4 250 46 24 -0.9 -0.5 | -57.0 -70.6 255 42 22 -0.3 -0.2
38000 -54.3 -65.7 250 44 23 5.0 2.7 | -54.3 -65.7 255 43 22 5.0 2.7
36000 -51.3 -60.3 250 42 22 5.0 2.7 | -51.3 -60.3 255 43 22 5.0 2.7
34000 -47.3 -53.1 250 40 20 8.0 4.4 | -47.2 -53.0 255 41 21 8.5 4.6
32000 -42.5 -44.5 250 38 20 8.0 4.4 | -42.1 -43.8 250 39 20 8.5 4.6
30000 -37.9 -36.2 250 38 19 7.6 4.1 | -37.4 -35.3 250 37 19 7.4 4.0
29000 -35.6 -32.1 250 38 19 7.6 4.1 | -35.1 -31.2 250 36 19 7.4 4.0
28000 -33.4 -28.1 250 38 20 7.6 4.1 | -32.9 -27.2 245 35 18 7.4 4.0
27000 -31.1 -24.0 250 37 19 7.4 4.1 | -30.7 -23.3 245 34 18 7.2 4.0
26000 -28.9 -20.0 250 36 19 7.4 4.1 | -28.6 -19.5 245 33 17 7.2 4.0
25000 -26.7 -16.1 250 35 18 7.4 4.1 | -26.4 -15.5 245 32 16 7.2 4.0
24000 -23.9 -11.0 250 34 17 7.7 4.2 | -23.7 -10.7 245 30 15 7.1 3.9
23000 -21.6 -6.9 250 35 18 7.7 4.2 | -21.6 -6.9 245 28 15 7.1 3.9
22000 -19.2 -2.6 245 35 18 7.7 4.2 | -19.4 -2.9 245 27 14 7.1 3.9
21000 -16.9 1.6 245 36 18 7.7 4.2 | -17.3 0.9 245 26 13 7.4 4.0
20000 -14.6 5.7 240 36 18 7.7 4.2 | -15.1 4.8 245 26 13 7.4 4.1
19500 -13.5 7.7 240 36 18 7.7 4.2 | -14.0 6.8 245 26 13 7.4 4.1
19000 -12.3 9.9 240 36 19 7.9 4.3 | -12.9 8.8 245 26 13 7.7 4.2
18500 -11.1 12.0 240 35 18 8.1 4.4 | -11.7 10.9 245 25 13 8.0 4.4
18000 -9.9 14.2 240 34 17 8.1 4.5 | -10.5 13.1 245 24 12 8.0 4.4
17500 -8.7 16.3 240 32 17 8.1 4.4 | -9.3 15.3 245 23 12 8.7 4.8
17000 -7.5 18.5 240 30 16 8.1 4.4 | -8.0 17.6 245 22 11 8.6 4.7
16500 -6.4 20.5 240 28 15 8.1 4.4 | -6.7 19.9 245 21 11 8.7 4.8
16000 -5.2 22.6 240 27 14 8.1 4.5 | -5.4 22.3 245 20 10 8.8 4.8
15500 -4.0 24.8 240 25 13 8.2 4.5 | -4.1 24.6 245 19 10 8.9 4.9
15000 -2.7 27.1 245 23 12 8.6 4.7 | -2.8 27.0 245 18 9 9.0 5.0
14500 -1.5 29.3 245 22 11 8.6 4.7 | -1.5 29.3 245 18 9 9.0 5.0
14000 -0.2 31.6 245 20 10 8.9 4.9 | -0.2 31.6 245 17 9 9.1 5.0
13500 1.1 34.0 245 19 10 8.9 4.9 | 1.2 34.2 240 16 8 9.1 5.0
13000 2.4 36.3 245 18 9 9.2 5.0 | 2.6 36.7 240 16 8 9.3 5.1
12500 3.8 38.8 250 17 9 9.2 5.0 | 3.9 39.0 240 16 8 9.3 5.1
12000 5.1 41.2 250 17 9 9.2 5.0 | 5.3 41.5 240 15 8 9.5 5.2
11500 6.5 43.7 250 16 8 9.1 5.0 | 6.8 44.2 240 15 8 9.6 5.2
11000 7.8 46.0 255 16 8 8.1 4.4 | 8.2 46.8 245 15 8 8.7 4.8
10500 8.9 48.0 255 16 8 6.9 3.8 | 9.4 48.9 245 14 7 8.2 4.5
10250 9.5 49.1 250 16 8 11.1 6.1 | 10.1 50.2 245 14 7 11.3 6.2
10000 10.5 50.9 250 16 8 11.3 6.2 | 11.0 51.8 245 14 7 11.1 6.1
9750 11.1 52.0 250 16 8 7.5 4.1 | 11.7 53.1 245 14 7 8.6 4.7
9500 11.7 53.1 250 16 8 8.2 4.5 | 12.3 54.1 245 13 7 9.1 5.0
9250 12.3 54.1 250 16 8 9.3 5.1 | 13.0 55.4 250 13 7 9.6 5.3
9000 13.1 55.6 250 15 8 8.7 4.8 | 13.8 56.8 245 13 7 9.9 5.4
8750 14.1 57.4 245 14 7 7.5 4.1 | 15.2 59.4 250 12 6 9.6 5.3
8500 14.7 58.5 240 13 7 6.4 3.5 | 15.9 60.6 250 12 6 8.9 4.9
8250 15.1 59.2 240 13 6 5.3 2.9 | 16.5 61.7 255 11 6 9.3 5.1
8000 15.5 59.9 235 11 6 5.6 3.1 | 17.3 63.1 255 11 6 10.4 5.7
7750 16.0 60.8 225 10 5 6.2 3.4 | 18.1 64.6 250 11 6 10.7 5.9
7500 16.4 61.5 220 8 4 4.7 2.6 | 18.8 65.8 250 11 5 9.3 5.1
7250 16.7 62.1 210 7 4 3.7 2.0 | 19.5 67.1 255 11 6 8.3 4.5
7000 17.1 62.8 205 6 3 7.1 3.9 | 20.2 68.4 255 11 6 10.5 5.7
6750 17.7 63.9 195 6 3 8.9 4.9 | 21.0 69.8 255 10 5 11.4 6.3
6500 18.3 64.9 190 5 3 8.4 4.6 | 21.8 71.2 255 10 5 11.0 6.0
6250 19.0 66.2 180 5 2 8.8 4.8 | 22.7 72.9 255 10 5 11.7 6.4
6000 19.6 67.3 165 4 2 8.0 4.4 | 23.5 74.3 255 10 5 8.1 4.4
5750 20.3 68.5 180 4 2 12.2 6.7 | 24.1 75.4 255 9 5 13.0 7.1
5500 22.1 71.8 155 3 2 46.1 25.3 | 27.2 81.0 260 9 5 91.7 50.3
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
06/02/2024 at 1500 MDT | 06/02/2024 at 1800 MDT
|
CAPE... +33.7 LI... +0.3 | CAPE... +86.2 LI... -0.2
CINH... -7.9 K Index... +14.6 | CINH... -7.8 K Index... +19.2
|
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 -69.3 265 32 16 0.8 0.5 | -56.5 -69.7 270 29 15 0.6 0.3
45000 -55.3 -67.5 265 34 18 -0.3 -0.2 | -55.8 -68.4 285 30 15 -0.6 -0.3
40000 -55.8 -68.4 265 36 19 -0.1 -0.1 | -56.7 -70.1 320 34 18 0.2 0.1
38000 -53.8 -64.8 260 37 19 3.7 2.0 | -53.9 -65.0 325 35 18 5.1 2.8
36000 -51.6 -60.9 250 38 20 3.7 2.0 | -50.9 -59.6 330 37 19 5.1 2.8
34000 -47.8 -54.0 250 37 19 8.6 4.7 | -46.8 -52.2 330 36 19 8.1 4.4
32000 -42.6 -44.7 255 34 18 8.6 4.7 | -42.0 -43.6 320 34 17 8.1 4.4
30000 -37.6 -35.7 260 32 16 8.2 4.5 | -37.2 -35.0 310 30 16 7.7 4.2
29000 -35.2 -31.4 265 31 16 8.2 4.5 | -34.9 -30.8 305 28 14 7.7 4.2
28000 -32.7 -26.9 270 30 15 8.2 4.5 | -32.6 -26.7 300 26 13 7.7 4.2
27000 -30.4 -22.7 270 29 15 6.9 3.8 | -29.8 -21.6 295 25 13 7.4 4.0
26000 -27.9 -18.2 265 29 15 6.9 3.8 | -27.7 -17.9 290 25 13 7.4 4.1
25000 -25.9 -14.6 260 28 15 6.9 3.8 | -25.5 -13.9 285 25 13 7.4 4.1
24000 -23.8 -10.8 255 27 14 6.7 3.7 | -23.3 -9.9 280 24 12 7.3 4.0
23000 -21.8 -7.2 250 24 12 6.7 3.7 | -21.2 -6.2 270 23 12 7.3 4.0
22000 -19.8 -3.6 245 22 11 6.6 3.6 | -19.0 -2.2 265 22 11 7.3 4.0
21000 -17.5 0.5 240 21 11 8.1 4.5 | -16.8 1.8 260 22 11 7.5 4.1
20000 -15.1 4.8 240 21 11 8.1 4.5 | -14.6 5.7 250 22 11 7.6 4.1
19500 -13.9 7.0 235 21 11 8.2 4.5 | -13.5 7.7 245 22 11 7.6 4.2
19000 -12.7 9.1 235 21 11 8.4 4.6 | -12.3 9.9 245 22 11 7.9 4.3
18500 -11.4 11.5 235 21 11 8.6 4.7 | -11.1 12.0 240 22 11 8.2 4.5
18000 -10.2 13.6 235 21 11 8.6 4.7 | -9.9 14.2 240 22 12 8.1 4.4
17500 -8.8 16.2 235 21 11 9.3 5.1 | -8.6 16.5 240 22 12 9.1 5.0
17000 -7.5 18.5 235 20 11 9.2 5.1 | -7.3 18.9 240 22 11 9.0 4.9
16500 -6.1 21.0 235 20 10 9.3 5.1 | -5.9 21.4 240 22 11 9.2 5.1
16000 -4.7 23.5 235 20 10 9.3 5.1 | -4.5 23.9 240 22 11 9.4 5.1
15500 -3.3 26.1 235 20 10 9.3 5.1 | -3.1 26.4 240 21 11 9.4 5.1
15000 -1.9 28.6 235 19 10 9.4 5.2 | -1.7 28.9 245 21 11 9.4 5.1
14500 -0.5 31.1 235 19 10 9.4 5.2 | -0.3 31.5 245 21 11 9.4 5.2
14000 0.9 33.6 240 19 10 9.4 5.2 | 1.1 34.0 245 20 10 9.3 5.1
13500 2.3 36.1 240 18 10 9.4 5.2 | 2.4 36.3 250 20 10 9.3 5.1
13000 3.7 38.7 240 18 9 9.2 5.1 | 3.8 38.8 255 19 10 9.1 5.0
12500 5.0 41.0 245 18 9 9.2 5.0 | 5.2 41.4 255 19 10 9.1 5.0
12000 6.4 43.5 245 18 9 9.3 5.1 | 6.5 43.7 260 18 9 9.2 5.0
11500 7.8 46.0 245 18 9 9.4 5.2 | 7.9 46.2 260 18 9 9.2 5.0
11000 9.2 48.6 250 17 9 8.3 4.5 | 9.2 48.6 265 18 9 7.7 4.2
10500 10.3 50.5 250 17 9 7.9 4.3 | 10.3 50.5 270 17 9 6.9 3.8
10250 11.0 51.8 255 17 9 11.8 6.5 | 10.9 51.6 270 17 9 11.8 6.5
10000 12.0 53.6 255 17 9 11.4 6.3 | 11.9 53.4 275 16 8 11.2 6.2
9750 12.7 54.9 255 17 9 8.4 4.6 | 12.5 54.5 275 16 8 7.2 3.9
9500 13.3 55.9 255 17 9 8.9 4.9 | 13.0 55.4 280 16 8 7.7 4.2
9250 14.0 57.2 255 17 9 10.0 5.5 | 14.4 57.9 285 15 8 10.4 5.7
9000 14.8 58.6 255 17 9 10.7 5.9 | 15.1 59.2 285 15 7 8.3 4.6
8750 16.3 61.3 255 17 9 10.2 5.6 | 15.7 60.3 290 14 7 9.1 5.0
8500 17.1 62.8 255 17 9 9.3 5.1 | 16.4 61.5 290 14 7 8.0 4.4
8250 17.8 64.0 260 17 9 9.5 5.2 | 17.0 62.6 295 14 7 8.5 4.7
8000 18.5 65.3 260 17 9 10.4 5.7 | 17.7 63.9 295 14 7 10.1 5.5
7750 19.3 66.7 260 17 9 10.7 5.9 | 18.4 65.1 295 14 7 10.2 5.6
7500 20.1 68.2 260 17 9 9.2 5.1 | 19.2 66.6 295 13 7 9.2 5.0
7250 20.7 69.3 260 17 9 8.1 4.4 | 19.8 67.6 295 14 7 8.3 4.6
7000 21.4 70.5 260 17 9 10.4 5.7 | 20.5 68.9 295 14 7 10.2 5.6
6750 22.2 72.0 260 16 8 11.5 6.3 | 21.3 70.3 295 13 7 11.1 6.1
6500 23.1 73.6 260 16 8 10.9 6.0 | 22.1 71.8 300 13 7 10.7 5.9
6250 23.9 75.0 260 16 8 11.5 6.3 | 22.9 73.2 300 13 7 11.2 6.1
6000 24.7 76.5 265 16 8 8.4 4.6 | 23.7 74.7 300 13 7 8.2 4.5
5750 25.3 77.5 260 14 7 13.2 7.2 | 24.2 75.6 300 12 6 9.7 5.3
5500 28.2 82.8 265 13 7 83.7 45.9 | 26.3 79.3 300 11 6 59.2 32.5
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
________________________________________________________________________________
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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