Soaring Guidance
Issued by NWS Grand Junction, CO
Issued by NWS Grand Junction, CO
263
UXUS97 KGJT 171307
SRGGJT
Soaring Forecast
National Weather Service Grand Junction, Colorado
707 AM MDT Monday, June 17, 2024
This forecast is for Monday, June 17, 2024:
If the trigger temperature of 84.3 F/29.1 C is reached...then
Thermal Soaring Index....................... Excellent
Maximum rate of lift........................ 1478 ft/min (7.5 m/s)
Maximum height of thermals.................. 20366 ft MSL (15527 ft AGL)
Forecast maximum temperature................... 95.0 F/35.5 C
Time of trigger temperature.................... 1030 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................. 14875 ft MSL (10036 ft AGL)
Thermal soaring outlook for Tuesday 06/18...... Excellent
Wave Soaring Index............................. Not available
Remarks...
Sunrise/Sunset.................... 05:47:48 / 20:42:42 MDT
Total possible sunshine........... 14 hr 54 min 55 sec (894 min 55 sec)
Altitude of sun at 13:15:15 MDT... 73.96 degrees
Upper air data from rawinsonde observation taken on 06/17/2024 at 0600 MDT
Freezing level.................. 15524 ft MSL (10685 ft AGL)
Convective condensation level... 22930 ft MSL (18091 ft AGL)
Lifted condensation level....... 22142 ft MSL (17303 ft AGL)
Lifted index.................... +1.8
K index......................... +5.0
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 -59.9 -75.8 240 50 26 3.7 2.0 94.9 202.8 34.7 M M
45000 -57.2 -71.0 265 61 31 -5.2 -2.8 74.8 166.7 24.7 M M
40000 -54.7 -66.5 275 50 26 -3.0 -1.7 55.9 132.6 13.9 M M
38000 -50.5 -58.9 270 50 26 7.3 4.0 52.3 126.2 11.9 M M
36000 -46.2 -51.2 260 45 23 7.3 4.0 50.2 122.3 10.7 M M
34000 -41.9 -43.4 260 50 26 7.2 3.9 48.0 118.4 9.3 M M
32000 -36.7 -34.1 250 45 23 9.2 5.0 46.9 116.5 8.8 M M
30000 -32.1 -25.8 250 49 25 6.9 3.8 45.3 113.6 7.7 M M
29000 -30.0 -22.0 255 51 26 7.5 4.1 44.3 111.8 7.1 M M
28000 -27.7 -17.9 235 48 25 7.7 4.2 43.4 110.2 6.5 M M
27000 -26.9 -16.4 235 46 23 3.9 2.1 40.8 105.4 4.5 M M
26000 -24.9 -12.8 235 47 24 6.5 3.6 39.6 103.3 3.5 M M
25000 -22.7 -8.9 225 44 23 9.5 5.2 38.7 101.7 2.8 M M
24000 -19.9 -3.8 225 43 22 9.6 5.3 38.6 101.5 2.8 M M
23000 -17.2 1.0 225 44 23 7.0 3.8 38.4 101.2 2.6 M M
22000 -15.4 4.3 225 40 21 6.6 3.6 37.1 98.8 1.5 M M
21000 -13.4 7.9 225 44 23 6.8 3.8 36.0 96.8 0.6 M M
20000 -10.7 12.7 215 40 21 7.2 4.0 34.8 94.7 -0.4 1432 7.3
19500 -9.7 14.5 215 39 20 7.0 3.9 34.4 93.9 -0.8 1386 7.0
19000 -8.6 16.5 215 40 21 7.8 4.3 33.9 93.1 -1.2 1339 6.8
18500 -7.3 18.9 220 42 22 8.3 4.6 33.7 92.6 -1.4 1287 6.5
18000 -6.1 21.0 220 44 23 8.3 4.6 33.5 92.2 -1.6 1234 6.3
17500 -4.8 23.4 220 45 23 8.3 4.6 33.2 91.8 -1.9 1182 6.0
17000 -3.6 25.5 215 46 24 8.3 4.6 33.0 91.3 -2.1 1129 5.7
16500 -2.3 27.9 215 42 21 8.3 4.6 32.7 90.9 -2.3 1077 5.5
16000 -1.1 30.0 210 36 18 8.4 4.6 32.5 90.4 -2.5 1024 5.2
15500 0.2 32.4 210 35 18 8.4 4.6 32.3 90.1 -2.8 971 4.9
15000 1.5 34.7 210 36 19 8.5 4.6 32.0 89.7 -3.0 918 4.7
14500 2.7 36.9 215 32 16 8.0 4.4 31.8 89.2 -3.2 866 4.4
14000 3.8 38.8 220 27 14 7.8 4.3 31.5 88.6 -3.6 818 4.2
13500 5.0 41.0 225 26 13 7.8 4.3 31.1 88.0 -3.9 769 3.9
13000 6.2 43.2 235 25 13 8.9 4.9 30.9 87.6 -4.2 717 3.6
12500 7.5 45.5 235 24 12 8.8 4.8 30.8 87.4 -4.3 663 3.4
12000 8.8 47.8 245 23 12 8.8 4.8 30.6 87.1 -4.5 609 3.1
11500 10.1 50.2 245 25 13 8.8 4.8 30.4 86.8 -4.7 555 2.8
11000 11.4 52.5 245 26 13 8.8 4.8 30.3 86.5 -4.9 501 2.5
10500 12.8 55.0 250 26 13 8.8 4.8 30.1 86.2 -5.1 447 2.3
10250 13.4 56.1 250 26 14 8.7 4.8 30.0 86.0 -5.2 420 2.1
10000 14.0 57.2 245 26 14 8.6 4.7 29.9 85.9 -5.3 394 2.0
9750 14.7 58.5 250 26 13 8.6 4.7 29.9 85.7 -5.4 367 1.9
9500 15.3 59.5 245 26 13 8.6 4.7 29.8 85.6 -5.5 340 1.7
9250 16.0 60.8 250 25 13 8.6 4.7 29.7 85.5 -5.5 313 1.6
9000 16.6 61.9 260 24 12 8.6 4.7 29.6 85.3 -5.6 286 1.5
8750 17.3 63.1 260 24 12 8.6 4.7 29.5 85.2 -5.7 259 1.3
8500 17.9 64.2 260 23 12 8.6 4.7 29.5 85.0 -5.8 232 1.2
8250 18.6 65.5 255 22 11 8.6 4.7 29.4 84.9 -5.9 205 1.0
8000 19.2 66.6 255 20 10 8.6 4.7 29.3 84.7 -6.0 179 0.9
7750 19.9 67.8 250 20 10 8.6 4.7 29.2 84.6 -6.1 152 0.8
7500 20.5 68.9 245 19 10 8.6 4.7 29.1 84.4 -6.2 125 0.6
7250 21.2 70.2 245 19 10 8.6 4.7 29.0 84.3 -6.3 98 0.5
7000 21.8 71.2 245 20 10 8.7 4.8 28.9 84.1 -6.4 71 0.4
6750 22.5 72.5 240 19 10 8.3 4.6 28.9 83.9 -6.5 44 0.2
6500 23.1 73.6 235 13 7 9.7 5.3 28.8 83.8 -6.6 17 0.1
6250 23.8 74.8 220 8 4 4.7 2.6 28.7 83.6 -6.7 M M
6000 23.9 75.0 160 5 3 -0.3 -0.1 28.0 82.4 -7.4 M M
5750 24.1 75.4 150 10 5 5.5 3.0 27.4 81.4 -7.9 M M
5500 24.5 76.1 150 13 7 0.8 0.5 27.1 80.7 -8.3 M M
5250 24.0 75.2 145 14 7 -10.8 -5.9 25.9 78.6 -9.5 M M
5000 23.1 73.6 125 9 5 -11.0 -6.0 24.3 75.7 -11.1 M M
* * * * * * Numerical weather prediction model forecast data valid * * * * * *
06/17/2024 at 0900 MDT | 06/17/2024 at 1200 MDT
|
CAPE... 0.0 LI... +4.0 | CAPE... 0.0 LI... +2.8
CINH... 0.0 K Index... +6.0 | CINH... -0.1 K Index... +10.1
|
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 -60.0 -76.0 245 51 26 1.5 0.8 | -60.1 -76.2 240 49 25 1.3 0.7
45000 -57.7 -71.9 250 58 30 1.7 1.0 | -57.9 -72.2 250 58 30 1.9 1.1
40000 -54.6 -66.3 260 60 31 7.9 4.3 | -55.0 -67.0 255 62 32 4.6 2.5
38000 -50.0 -58.0 255 57 29 7.7 4.2 | -50.0 -58.0 255 60 31 7.5 4.1
36000 -45.4 -49.7 250 54 28 7.6 4.2 | -45.5 -49.9 250 59 30 7.5 4.1
34000 -41.0 -41.8 250 53 27 7.3 4.0 | -40.7 -41.3 250 57 29 8.2 4.5
32000 -36.6 -33.9 250 52 27 7.3 4.0 | -35.9 -32.6 250 54 28 8.2 4.5
30000 -32.2 -26.0 250 52 27 7.4 4.1 | -31.4 -24.5 250 53 27 6.9 3.8
29000 -30.0 -22.0 250 51 27 7.4 4.1 | -29.4 -20.9 245 53 27 6.9 3.8
28000 -27.8 -18.0 245 51 26 7.4 4.1 | -27.4 -17.3 245 52 27 6.9 3.8
27000 -25.7 -14.3 245 50 26 6.9 3.8 | -25.2 -13.4 245 52 27 7.3 4.0
26000 -23.6 -10.5 245 49 25 6.9 3.8 | -23.0 -9.4 245 50 26 7.3 4.0
25000 -21.5 -6.7 240 48 25 6.9 3.8 | -20.9 -5.6 240 49 25 7.3 4.0
24000 -19.0 -2.2 240 46 24 6.4 3.5 | -18.3 -0.9 240 48 25 6.2 3.4
23000 -17.2 1.0 235 46 23 6.4 3.5 | -16.4 2.5 235 47 24 6.2 3.4
22000 -15.3 4.5 235 45 23 6.4 3.5 | -14.6 5.7 235 46 24 6.2 3.4
21000 -13.3 8.1 230 43 22 7.2 3.9 | -12.7 9.1 230 45 23 6.2 3.4
20000 -11.1 12.0 230 41 21 7.2 3.9 | -10.9 12.4 230 44 23 6.2 3.4
19500 -10.1 13.8 225 40 21 7.2 3.9 | -10.0 14.0 230 43 22 6.2 3.4
19000 -9.0 15.8 225 39 20 7.1 3.9 | -9.1 15.6 225 43 22 6.3 3.5
18500 -8.0 17.6 225 38 20 7.0 3.8 | -8.2 17.2 225 41 21 6.4 3.5
18000 -6.9 19.6 225 37 19 7.0 3.8 | -7.3 18.9 225 39 20 6.4 3.5
17500 -5.9 21.4 225 36 19 7.4 4.1 | -6.3 20.7 225 38 19 6.8 3.7
17000 -4.8 23.4 225 35 18 7.4 4.1 | -5.3 22.5 225 36 18 6.8 3.8
16500 -3.6 25.5 220 34 18 7.4 4.1 | -4.3 24.3 225 34 17 7.1 3.9
16000 -2.5 27.5 220 33 17 7.3 4.0 | -3.2 26.2 225 32 17 7.6 4.2
15500 -1.5 29.3 220 32 16 7.3 4.0 | -2.0 28.4 225 31 16 7.5 4.1
15000 -0.4 31.3 220 31 16 7.7 4.2 | -0.8 30.6 225 30 15 8.8 4.9
14500 0.8 33.4 220 29 15 7.7 4.2 | 0.4 32.7 220 29 15 8.7 4.8
14000 1.9 35.4 220 28 14 8.2 4.5 | 1.7 35.1 220 28 14 9.0 5.0
13500 3.2 37.8 220 26 14 8.3 4.6 | 3.1 37.6 220 27 14 9.1 5.0
13000 4.4 39.9 220 25 13 8.6 4.7 | 4.5 40.1 220 26 14 9.3 5.1
12500 5.7 42.3 220 24 12 8.7 4.8 | 5.9 42.6 215 26 13 9.4 5.2
12000 7.0 44.6 220 23 12 8.6 4.7 | 7.3 45.1 215 25 13 9.5 5.2
11500 8.3 46.9 225 23 12 8.5 4.7 | 8.7 47.7 215 25 13 9.6 5.2
11000 9.6 49.3 225 22 11 8.3 4.6 | 10.1 50.2 215 24 12 9.3 5.1
10500 10.8 51.4 225 22 11 7.9 4.3 | 11.4 52.5 220 23 12 8.9 4.9
10250 11.4 52.5 225 22 11 9.3 5.1 | 12.2 54.0 220 23 12 10.5 5.8
10000 12.1 53.8 225 21 11 9.6 5.3 | 13.0 55.4 215 23 12 10.9 6.0
9750 12.8 55.0 225 21 11 8.5 4.7 | 13.8 56.8 215 23 12 10.3 5.7
9500 13.4 56.1 225 21 11 8.5 4.7 | 14.5 58.1 215 22 12 10.4 5.7
9250 14.1 57.4 225 20 10 8.1 4.4 | 15.3 59.5 215 22 11 9.7 5.3
9000 14.6 58.3 225 20 10 7.7 4.2 | 16.0 60.8 215 22 11 9.3 5.1
8750 15.2 59.4 220 19 10 8.2 4.5 | 17.5 63.5 215 22 11 10.2 5.6
8500 16.5 61.7 225 18 9 8.7 4.8 | 18.2 64.8 215 21 11 10.2 5.6
8250 17.1 62.8 225 18 9 6.7 3.7 | 19.0 66.2 215 21 11 9.3 5.1
8000 17.5 63.5 215 17 9 6.0 3.3 | 19.7 67.5 215 21 11 9.6 5.2
7750 18.0 64.4 210 16 8 7.5 4.1 | 20.4 68.7 215 21 11 10.2 5.6
7500 18.6 65.5 210 15 8 7.0 3.9 | 21.2 70.2 215 21 11 10.4 5.7
7250 19.1 66.4 205 15 8 7.1 3.9 | 21.9 71.4 215 20 10 9.1 5.0
7000 19.6 67.3 205 15 7 8.2 4.5 | 22.6 72.7 215 20 10 9.5 5.2
6750 20.3 68.5 200 14 7 8.8 4.8 | 23.4 74.1 215 19 10 11.1 6.1
6500 20.9 69.6 195 13 7 9.4 5.1 | 24.2 75.6 215 19 10 10.8 5.9
6250 21.7 71.1 195 12 6 11.1 6.1 | 25.0 77.0 215 18 9 12.2 6.7
6000 22.6 72.7 195 12 6 14.7 8.1 | 26.2 79.2 215 18 9 19.7 10.8
5750 23.9 75.0 195 11 5 19.6 10.7 | 28.0 82.4 215 16 8 29.8 16.4
5500 25.2 77.4 190 9 5 11.1 6.1 | 29.9 85.8 215 15 8 12.4 6.8
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
06/17/2024 at 1500 MDT | 06/17/2024 at 1800 MDT
|
CAPE... +0.3 LI... +0.2 | CAPE... +1.9 LI... 0.0
CINH... 0.0 K Index... +12.2 | CINH... -2.8 K Index... +11.6
|
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 -60.0 -76.0 240 50 26 1.4 0.8 | -59.8 -75.6 240 52 27 1.2 0.7
45000 -57.7 -71.9 245 60 31 2.2 1.2 | -57.6 -71.7 245 64 33 2.3 1.3
40000 -54.3 -65.7 250 68 35 4.4 2.4 | -54.2 -65.6 245 73 37 4.3 2.4
38000 -49.7 -57.5 250 68 35 6.9 3.8 | -49.7 -57.5 245 75 38 6.6 3.6
36000 -45.6 -50.1 250 68 35 6.9 3.8 | -45.7 -50.3 245 77 39 6.7 3.7
34000 -40.9 -41.6 250 66 34 8.2 4.5 | -41.0 -41.8 245 76 39 8.3 4.6
32000 -36.0 -32.8 245 63 32 8.2 4.5 | -36.1 -33.0 245 73 38 8.3 4.6
30000 -31.3 -24.3 245 59 30 7.4 4.1 | -31.5 -24.7 240 69 35 7.2 3.9
29000 -29.1 -20.4 245 57 29 7.4 4.1 | -29.3 -20.7 240 65 34 7.2 3.9
28000 -26.9 -16.4 245 55 28 7.4 4.1 | -27.2 -17.0 240 62 32 7.2 3.9
27000 -24.8 -12.6 240 53 27 6.5 3.6 | -25.2 -13.4 240 59 30 6.1 3.3
26000 -22.9 -9.2 240 51 26 6.5 3.6 | -23.4 -10.1 235 55 28 6.1 3.3
25000 -21.0 -5.8 240 50 26 6.6 3.6 | -21.6 -6.9 235 52 27 6.1 3.3
24000 -18.7 -1.7 235 48 24 5.9 3.2 | -19.8 -3.6 235 48 25 5.9 3.3
23000 -16.9 1.6 235 46 24 5.9 3.2 | -17.6 0.3 230 45 23 6.0 3.3
22000 -15.1 4.8 235 44 23 5.9 3.2 | -15.9 3.4 230 43 22 5.9 3.2
21000 -13.4 7.9 230 42 22 6.1 3.3 | -13.9 7.0 225 41 21 7.4 4.1
20000 -11.6 11.1 230 40 21 6.2 3.4 | -11.7 10.9 225 40 21 7.5 4.1
19500 -10.7 12.7 230 39 20 6.2 3.4 | -10.6 12.9 225 39 20 7.5 4.1
19000 -9.8 14.4 225 38 20 6.8 3.7 | -9.5 14.9 220 39 20 8.0 4.4
18500 -8.6 16.5 225 37 19 8.4 4.6 | -8.2 17.2 220 39 20 9.0 5.0
18000 -7.4 18.7 225 36 19 8.3 4.6 | -6.8 19.8 220 38 20 9.0 4.9
17500 -6.2 20.8 225 35 18 9.0 4.9 | -5.5 22.1 220 38 20 9.3 5.1
17000 -4.8 23.4 220 34 18 9.0 5.0 | -4.1 24.6 220 38 19 9.4 5.1
16500 -3.5 25.7 220 33 17 9.1 5.0 | -2.7 27.1 220 38 19 9.4 5.2
16000 -2.1 28.2 220 33 17 9.3 5.1 | -1.3 29.7 220 37 19 9.5 5.2
15500 -0.7 30.7 220 33 17 9.3 5.1 | 0.1 32.2 220 37 19 9.4 5.2
15000 0.7 33.3 220 32 17 9.6 5.2 | 1.6 34.9 220 37 19 9.7 5.3
14500 2.2 36.0 220 32 16 9.5 5.2 | 3.0 37.4 220 36 19 9.7 5.3
14000 3.6 38.5 220 31 16 9.5 5.2 | 4.4 39.9 220 36 19 9.5 5.2
13500 5.0 41.0 220 31 16 9.5 5.2 | 5.9 42.6 220 36 19 9.5 5.2
13000 6.4 43.5 220 31 16 9.6 5.3 | 7.3 45.1 225 36 18 9.5 5.2
12500 7.9 46.2 220 31 16 9.6 5.3 | 8.7 47.7 225 35 18 9.5 5.2
12000 9.3 48.7 220 30 16 9.7 5.3 | 10.1 50.2 225 35 18 9.6 5.2
11500 10.7 51.3 220 30 15 9.7 5.3 | 11.6 52.9 225 35 18 9.7 5.3
11000 12.2 54.0 220 30 15 9.6 5.3 | 13.0 55.4 225 34 18 9.6 5.2
10500 13.6 56.5 220 29 15 9.5 5.2 | 14.3 57.7 225 33 17 9.0 4.9
10250 14.3 57.7 220 29 15 10.5 5.7 | 15.1 59.2 225 33 17 10.7 5.9
10000 15.1 59.2 220 29 15 10.5 5.8 | 15.9 60.6 225 33 17 10.6 5.8
9750 15.9 60.6 220 29 15 10.2 5.6 | 16.6 61.9 230 33 17 10.1 5.6
9500 16.7 62.1 220 28 15 10.3 5.6 | 17.4 63.3 230 32 16 9.9 5.4
9250 17.4 63.3 220 28 14 9.7 5.3 | 18.1 64.6 230 31 16 9.8 5.4
9000 18.1 64.6 220 28 14 9.3 5.1 | 18.8 65.8 230 31 16 9.6 5.3
8750 19.6 67.3 220 28 14 10.7 5.9 | 19.6 67.3 230 31 16 10.0 5.5
8500 20.4 68.7 220 27 14 10.4 5.7 | 20.3 68.5 230 31 16 10.2 5.6
8250 21.2 70.2 220 27 14 9.1 5.0 | 21.8 71.2 230 30 15 9.2 5.1
8000 21.8 71.2 220 27 14 9.3 5.1 | 22.5 72.5 230 30 15 9.0 5.0
7750 22.6 72.7 220 26 14 10.2 5.6 | 23.2 73.8 230 29 15 9.7 5.3
7500 23.3 73.9 220 26 13 10.2 5.6 | 23.9 75.0 230 29 15 9.0 4.9
7250 24.1 75.4 220 25 13 9.5 5.2 | 24.6 76.3 235 28 15 11.1 6.1
7000 24.8 76.6 220 25 13 9.8 5.4 | 25.5 77.9 230 27 14 11.2 6.1
6750 25.6 78.1 220 24 12 10.9 6.0 | 26.2 79.2 230 26 13 9.4 5.1
6500 26.4 79.5 220 23 12 10.4 5.7 | 26.9 80.4 230 25 13 9.4 5.2
6250 27.2 81.0 220 23 12 11.8 6.5 | 27.6 81.7 235 24 12 11.0 6.0
6000 28.3 82.9 220 22 11 20.0 11.0 | 28.7 83.7 235 24 12 15.4 8.5
5750 30.2 86.4 225 20 10 30.1 16.5 | 29.9 85.8 235 22 11 17.3 9.5
5500 32.1 89.8 225 18 9 13.3 7.3 | 31.1 88.0 235 19 10 15.6 8.5
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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