Soaring Guidance
Issued by NWS Grand Junction, CO
Issued by NWS Grand Junction, CO
116
UXUS97 KGJT 301307
SRGGJT
Soaring Forecast
National Weather Service Grand Junction, Colorado
707 AM MDT Sunday, June 30, 2024
This forecast is for Sunday, June 30, 2024:
If the trigger temperature of 83.2 F/28.5 C is reached...then
Thermal Soaring Index....................... Good
Maximum rate of lift........................ 700 ft/min (3.6 m/s)
Maximum height of thermals.................. 15218 ft MSL (10379 ft AGL)
Forecast maximum temperature................... 91.0 F/33.2 C
Time of trigger temperature.................... 1000 MDT
Time of overdevelopment........................ 1200 MDT
Middle/high clouds during soaring window....... Broken/overcast opaque middle
Surface winds during soaring window............ 20 mph or less
Height of the -3 thermal index................. 9309 ft MSL (4469 ft AGL)
Thermal soaring outlook for Monday 07/01....... Good
Wave Soaring Index............................. Not available
Remarks...
Sunrise/Sunset.................... 05:51:49 / 20:44:10 MDT
Total possible sunshine........... 14 hr 52 min 21 sec (892 min 21 sec)
Altitude of sun at 13:17:59 MDT... 73.53 degrees
Upper air data from rawinsonde observation taken on 06/30/2024 at 0600 MDT
Freezing level.................. 15965 ft MSL (11126 ft AGL)
Convective condensation level... 13940 ft MSL (9101 ft AGL)
Lifted condensation level....... 14263 ft MSL (9424 ft AGL)
Lifted index.................... -2.7
K index......................... +30.8
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 -67.1 -88.8 260 31 16 4.5 2.5 80.8 177.5 28.0 M M
45000 -59.7 -75.5 240 60 31 -1.3 -0.7 67.7 153.9 21.9 M M
40000 -47.8 -54.0 235 58 30 9.3 5.1 63.5 146.3 20.6 M M
38000 -42.5 -44.5 225 60 31 8.2 4.5 62.6 144.6 20.5 M M
36000 -37.9 -36.2 225 61 31 7.2 4.0 60.8 141.4 19.7 M M
34000 -34.4 -29.9 235 55 28 6.0 3.3 57.5 135.5 17.9 M M
32000 -30.0 -22.0 230 56 29 6.4 3.5 54.7 130.4 16.2 M M
30000 -25.7 -14.3 235 50 26 3.9 2.1 52.6 126.7 15.1 M M
29000 -24.6 -12.3 245 36 19 7.2 4.0 50.3 122.5 13.4 M M
28000 -22.3 -8.1 245 36 19 7.5 4.1 49.4 121.0 12.9 M M
27000 -20.1 -4.2 245 39 20 7.5 4.1 48.6 119.4 12.4 M M
26000 -17.8 -0.0 245 31 16 7.6 4.2 47.7 117.9 11.9 M M
25000 -15.4 4.3 240 30 15 8.7 4.8 47.0 116.6 11.5 M M
24000 -13.8 7.2 240 27 14 4.4 2.4 45.4 113.7 10.3 M M
23000 -12.8 9.0 240 17 9 3.0 1.6 43.2 109.7 8.5 M M
22000 -11.2 11.8 240 10 5 5.5 3.0 41.4 106.6 7.2 M M
21000 -10.4 13.3 230 21 11 6.3 3.5 39.3 102.7 5.1 M M
20000 -9.5 14.9 225 20 10 5.7 3.1 37.0 98.6 3.1 M M
19500 -8.3 17.1 220 20 10 10.0 5.5 36.7 98.0 2.8 M M
19000 -7.1 19.2 215 20 10 7.2 3.9 36.4 97.5 2.6 M M
18500 -6.1 21.0 215 18 9 7.3 4.0 36.0 96.8 2.2 M M
18000 -5.0 23.0 215 14 7 7.1 3.9 35.6 96.0 1.8 M M
17500 -3.1 26.4 220 10 5 7.5 4.1 35.3 95.5 1.5 M M
17000 -2.1 28.2 225 9 5 7.6 4.2 34.9 94.8 1.1 M M
16500 -1.0 30.2 220 9 5 7.9 4.3 34.5 94.2 0.7 M M
16000 0.1 32.2 215 10 5 7.9 4.3 34.3 93.7 0.4 M M
15500 1.3 34.3 230 11 6 7.9 4.4 34.0 93.1 0.1 M M
15000 2.4 36.3 230 10 5 8.0 4.4 33.7 92.6 -0.2 870 4.4
14500 3.6 38.5 245 12 6 8.5 4.7 33.4 92.0 -0.5 821 4.2
14000 4.9 40.8 240 12 6 9.0 4.9 33.3 91.9 -0.6 767 3.9
13500 6.2 43.2 235 10 5 9.1 5.0 33.2 91.7 -0.7 712 3.6
13000 7.6 45.7 225 9 5 9.1 5.0 33.1 91.5 -0.8 657 3.3
12500 8.9 48.0 235 7 4 9.1 5.0 33.0 91.4 -1.0 603 3.1
12000 10.2 50.4 245 9 5 9.1 5.0 32.9 91.2 -1.1 548 2.8
11500 11.6 52.9 240 9 5 9.1 5.0 32.8 91.0 -1.2 494 2.5
11000 12.9 55.2 230 6 3 9.1 5.0 32.6 90.7 -1.4 439 2.2
10500 14.2 57.6 210 10 5 9.6 5.3 32.5 90.5 -1.5 385 2.0
10250 14.9 58.8 215 9 5 10.4 5.7 32.5 90.6 -1.5 355 1.8
10000 15.7 60.3 215 9 5 9.8 5.4 32.6 90.6 -1.5 326 1.7
9750 16.3 61.3 200 12 6 4.8 2.7 32.4 90.4 -1.7 301 1.5
9500 16.4 61.5 190 17 9 -0.6 -0.3 31.8 89.2 -2.3 291 1.5
9250 16.3 61.3 185 21 11 0.9 0.5 31.0 87.8 -3.1 286 1.5
9000 16.4 61.5 180 26 13 1.7 0.9 30.4 86.7 -3.7 274 1.4
8750 16.6 61.9 180 26 13 4.7 2.6 29.8 85.6 -4.3 262 1.3
8500 17.2 63.0 175 25 13 9.6 5.3 29.7 85.4 -4.5 237 1.2
8250 17.9 64.2 170 24 13 9.6 5.3 29.7 85.4 -4.5 209 1.1
8000 18.6 65.5 170 26 13 9.6 5.3 29.7 85.4 -4.5 180 0.9
7750 19.3 66.7 170 25 13 9.6 5.2 29.6 85.3 -4.6 152 0.8
7500 20.0 68.0 165 24 13 9.7 5.3 29.6 85.3 -4.6 124 0.6
7250 20.6 69.1 160 24 12 9.3 5.1 29.6 85.3 -4.6 95 0.5
7000 21.3 70.3 150 24 12 10.9 6.0 29.6 85.3 -4.7 67 0.3
6750 22.0 71.6 150 25 13 5.7 3.2 29.6 85.3 -4.8 41 0.2
6500 21.9 71.4 145 28 14 -4.3 -2.4 28.9 83.9 -5.6 35 0.2
6250 21.4 70.5 145 29 15 -7.2 -3.9 27.6 81.8 -6.8 42 0.2
6000 21.0 69.8 150 30 15 -3.9 -2.2 26.4 79.6 -8.0 49 0.2
5750 20.8 69.4 145 27 14 1.0 0.6 25.6 78.1 -8.9 45 0.2
5500 20.9 69.6 140 25 13 2.0 1.1 25.0 77.0 -9.6 36 0.2
5250 21.0 69.8 135 23 12 2.1 1.2 24.4 76.0 -10.3 27 0.1
5000 21.1 70.0 130 21 11 3.5 1.9 23.9 75.0 -10.9 14 0.1
* * * * * * Numerical weather prediction model forecast data valid * * * * * *
06/30/2024 at 0900 MDT | 06/30/2024 at 1200 MDT
|
CAPE... +226.5 LI... -2.7 | CAPE... +661.5 LI... -3.5
CINH... -78.2 K Index... +31.9 | CINH... -5.6 K Index... +32.5
|
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 -64.0 -83.2 245 30 15 2.8 1.5 | -63.6 -82.5 225 29 15 3.2 1.8
45000 -57.9 -72.2 240 46 24 6.0 3.3 | -57.5 -71.5 230 45 23 5.3 2.9
40000 -48.5 -55.3 235 61 31 7.6 4.2 | -48.8 -55.8 230 61 32 7.8 4.3
38000 -43.9 -47.0 230 60 31 7.6 4.2 | -44.2 -47.6 230 60 31 7.8 4.3
36000 -38.8 -37.8 230 60 31 7.8 4.3 | -38.9 -38.0 225 59 30 7.5 4.1
34000 -34.1 -29.4 230 57 29 7.7 4.2 | -34.4 -29.9 225 56 29 7.5 4.1
32000 -29.5 -21.1 230 54 28 6.7 3.7 | -29.9 -21.8 230 52 27 6.8 3.7
30000 -26.3 -15.3 230 46 24 5.4 3.0 | -26.5 -15.7 230 45 23 5.8 3.2
29000 -24.7 -12.5 235 42 21 5.4 2.9 | -24.7 -12.5 230 42 21 5.8 3.2
28000 -22.9 -9.2 235 38 20 7.9 4.3 | -22.8 -9.0 230 39 20 7.8 4.3
27000 -20.6 -5.1 235 35 18 7.6 4.2 | -20.5 -4.9 230 36 19 7.7 4.2
26000 -18.3 -0.9 235 32 16 7.6 4.2 | -18.3 -0.9 230 34 18 7.7 4.2
25000 -16.0 3.2 240 29 15 7.1 3.9 | -16.0 3.2 230 32 17 7.2 4.0
24000 -14.1 6.6 235 28 15 6.5 3.5 | -13.9 7.0 230 32 17 6.8 3.7
23000 -12.2 10.0 235 28 14 6.5 3.5 | -11.9 10.6 230 32 17 6.8 3.7
22000 -9.9 14.2 235 27 14 4.0 2.2 | -9.6 14.7 230 32 16 4.2 2.3
21000 -8.7 16.3 235 26 14 4.4 2.4 | -8.3 17.1 230 30 15 4.6 2.5
20000 -7.6 18.3 230 25 13 4.8 2.7 | -7.0 19.4 230 28 15 4.8 2.6
19500 -7.0 19.4 230 25 13 5.4 2.9 | -6.4 20.5 230 28 14 5.0 2.7
19000 -6.2 20.8 225 23 12 5.6 3.1 | -5.7 21.7 230 26 13 5.1 2.8
18500 -5.4 22.3 220 21 11 5.7 3.1 | -5.0 23.0 225 24 13 4.9 2.7
18000 -4.6 23.7 215 19 10 6.4 3.5 | -4.2 24.4 225 23 12 7.4 4.1
17500 -3.7 25.3 210 17 9 6.4 3.5 | -3.2 26.2 220 22 11 7.2 4.0
17000 -2.8 27.0 205 15 7 6.9 3.8 | -2.1 28.2 220 20 10 7.4 4.1
16500 -1.7 28.9 210 14 7 7.3 4.0 | -1.1 30.0 220 20 10 7.6 4.2
16000 -0.7 30.7 210 13 7 7.4 4.1 | 0.0 32.0 215 20 10 7.6 4.2
15500 0.4 32.7 210 12 6 7.8 4.3 | 1.1 34.0 215 19 10 7.2 3.9
15000 1.5 34.7 215 12 6 7.8 4.3 | 2.1 35.8 215 18 9 7.2 3.9
14500 2.7 36.9 215 12 6 7.9 4.4 | 3.2 37.8 215 17 9 7.8 4.3
14000 3.8 38.8 215 12 6 8.0 4.4 | 4.3 39.7 215 17 9 7.8 4.3
13500 5.0 41.0 215 12 6 8.1 4.4 | 5.4 41.7 215 16 8 8.2 4.5
13000 6.1 43.0 215 13 7 8.2 4.5 | 6.6 43.9 215 15 8 8.5 4.6
12500 7.3 45.1 215 13 7 8.3 4.5 | 7.9 46.2 215 15 8 8.8 4.8
12000 8.5 47.3 215 14 7 8.4 4.6 | 9.2 48.6 210 15 8 9.1 5.0
11500 9.7 49.5 215 15 7 8.5 4.6 | 10.5 50.9 210 14 7 9.2 5.0
11000 11.0 51.8 215 15 8 8.6 4.7 | 11.9 53.4 210 14 7 9.3 5.1
10500 12.2 54.0 215 15 8 8.6 4.7 | 13.2 55.8 210 14 7 8.1 4.5
10250 12.8 55.0 215 15 8 8.5 4.7 | 13.8 56.8 210 13 7 8.6 4.7
10000 13.4 56.1 215 15 8 8.4 4.6 | 14.5 58.1 210 13 7 10.5 5.7
9750 14.0 57.2 215 15 8 8.3 4.6 | 15.3 59.5 205 13 7 10.0 5.5
9500 14.6 58.3 215 15 8 8.9 4.9 | 16.0 60.8 205 13 7 10.0 5.5
9250 15.3 59.5 210 16 8 9.1 5.0 | 16.7 62.1 205 12 6 9.6 5.3
9000 15.9 60.6 210 16 8 7.5 4.1 | 17.4 63.3 205 12 6 9.2 5.0
8750 16.4 61.5 205 16 8 6.5 3.5 | 18.0 64.4 205 12 6 9.2 5.0
8500 16.9 62.4 205 16 8 7.3 4.0 | 18.7 65.7 205 12 6 8.7 4.8
8250 18.1 64.6 200 17 9 7.2 4.0 | 19.9 67.8 200 11 6 9.8 5.4
8000 18.5 65.3 195 17 9 6.2 3.4 | 20.7 69.3 200 11 6 12.5 6.9
7750 19.0 66.2 190 16 8 6.2 3.4 | 21.6 70.9 200 11 6 9.7 5.3
7500 19.4 66.9 185 15 8 6.0 3.3 | 22.2 72.0 200 11 6 7.4 4.1
7250 19.9 67.8 185 14 7 6.5 3.6 | 22.8 73.0 195 10 5 9.6 5.2
7000 20.4 68.7 180 13 7 7.8 4.3 | 23.6 74.5 195 10 5 12.7 7.0
6750 21.0 69.8 175 12 6 7.7 4.2 | 24.5 76.1 200 10 5 11.3 6.2
6500 21.5 70.7 170 11 6 7.0 3.9 | 25.3 77.5 195 10 5 9.9 5.4
6250 22.0 71.6 165 10 5 7.8 4.3 | 26.0 78.8 190 9 5 9.0 4.9
6000 22.7 72.9 165 9 5 10.5 5.8 | 26.8 80.2 195 9 5 14.4 7.9
5750 23.6 74.5 160 8 4 13.2 7.3 | 28.3 82.9 195 8 4 28.6 15.7
5500 24.4 75.9 155 7 4 7.6 4.2 | 30.1 86.2 190 8 4 8.2 4.5
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
06/30/2024 at 1500 MDT | 06/30/2024 at 1800 MDT
|
CAPE... +969.5 LI... -3.9 | CAPE... +989.5 LI... -4.3
CINH... -28.5 K Index... +34.5 | CINH... -46.6 K Index... +33.8
|
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 -64.4 -83.9 220 35 18 2.9 1.6 | -65.0 -85.0 225 38 20 2.4 1.3
45000 -58.2 -72.8 225 51 26 6.0 3.3 | -58.8 -73.8 230 52 27 6.8 3.7
40000 -48.7 -55.7 225 61 31 7.8 4.3 | -48.3 -54.9 225 58 30 7.8 4.3
38000 -44.0 -47.2 225 59 30 7.8 4.3 | -43.1 -45.6 225 56 29 7.8 4.3
36000 -38.8 -37.8 220 57 29 7.1 3.9 | -38.4 -37.1 220 54 28 7.2 4.0
34000 -34.5 -30.1 225 53 27 7.2 4.0 | -34.1 -29.4 220 50 26 7.3 4.0
32000 -30.2 -22.4 225 50 26 7.0 3.9 | -29.7 -21.5 220 46 24 7.9 4.3
30000 -26.4 -15.5 225 45 23 6.4 3.5 | -25.7 -14.3 220 43 22 6.8 3.7
29000 -24.5 -12.1 225 43 22 6.4 3.5 | -23.7 -10.7 220 42 22 6.8 3.7
28000 -22.6 -8.7 225 41 21 7.3 4.0 | -21.7 -7.1 220 40 21 6.2 3.4
27000 -20.4 -4.7 225 39 20 7.2 4.0 | -19.9 -3.8 220 38 20 6.3 3.5
26000 -18.3 -0.9 225 38 19 7.3 4.0 | -18.0 -0.4 225 37 19 6.3 3.5
25000 -16.2 2.8 225 36 18 6.9 3.8 | -16.2 2.8 225 35 18 6.3 3.4
24000 -14.3 6.3 225 34 18 6.5 3.6 | -14.4 6.1 225 34 17 6.1 3.4
23000 -11.9 10.6 225 33 17 6.6 3.6 | -12.2 10.0 225 33 17 6.1 3.4
22000 -10.1 13.8 225 31 16 5.7 3.2 | -10.4 13.3 225 32 16 5.7 3.1
21000 -8.4 16.9 225 29 15 5.9 3.2 | -8.7 16.3 230 30 16 5.7 3.2
20000 -6.7 19.9 225 27 14 5.9 3.2 | -7.1 19.2 230 29 15 5.8 3.2
19500 -5.9 21.4 225 26 13 6.1 3.4 | -6.2 20.8 230 28 15 6.0 3.3
19000 -5.0 23.0 225 25 13 6.3 3.5 | -5.4 22.3 235 27 14 6.2 3.4
18500 -4.1 24.6 225 24 12 6.3 3.4 | -4.5 23.9 235 26 14 6.1 3.3
18000 -3.2 26.2 225 23 12 6.9 3.8 | -3.5 25.7 235 25 13 7.2 3.9
17500 -2.2 28.0 225 22 11 6.9 3.8 | -2.5 27.5 235 24 13 7.2 3.9
17000 -1.2 29.8 220 22 11 7.1 3.9 | -1.5 29.3 240 24 12 7.6 4.2
16500 -0.1 31.8 220 21 11 7.4 4.0 | -0.4 31.3 235 23 12 8.0 4.4
16000 0.9 33.6 220 20 11 7.4 4.1 | 0.8 33.4 235 22 11 8.1 4.4
15500 2.0 35.6 220 20 10 7.9 4.3 | 2.0 35.6 235 21 11 8.1 4.5
15000 3.1 37.6 220 19 10 7.8 4.3 | 3.1 37.6 235 20 11 8.1 4.4
14500 4.3 39.7 220 19 10 8.0 4.4 | 4.3 39.7 235 20 10 8.9 4.9
14000 5.4 41.7 215 18 9 8.1 4.4 | 5.6 42.1 230 19 10 9.0 4.9
13500 6.6 43.9 215 18 9 8.4 4.6 | 6.9 44.4 230 19 10 8.9 4.9
13000 7.8 46.0 215 17 9 8.5 4.7 | 8.2 46.8 225 18 9 8.8 4.8
12500 9.1 48.4 215 17 9 8.7 4.7 | 9.5 49.1 225 18 9 8.9 4.9
12000 10.4 50.7 215 16 8 8.8 4.8 | 10.8 51.4 220 17 9 9.1 5.0
11500 11.6 52.9 215 16 8 8.9 4.9 | 12.1 53.8 220 17 9 9.1 5.0
11000 13.0 55.4 215 16 8 8.9 4.9 | 13.4 56.1 220 16 8 9.0 4.9
10500 14.3 57.7 215 15 8 7.2 3.9 | 14.7 58.5 215 16 8 7.6 4.1
10250 14.7 58.5 215 15 8 7.7 4.2 | 15.2 59.4 215 16 8 7.9 4.4
10000 15.5 59.9 215 15 8 10.5 5.8 | 15.9 60.6 215 16 8 10.2 5.6
9750 16.2 61.2 215 14 7 9.9 5.4 | 16.6 61.9 215 16 8 9.6 5.2
9500 16.9 62.4 215 14 7 9.6 5.3 | 17.3 63.1 210 16 8 9.9 5.4
9250 17.6 63.7 215 13 7 8.9 4.9 | 18.0 64.4 210 15 8 9.3 5.1
9000 18.2 64.8 215 13 7 8.9 4.9 | 18.7 65.7 210 15 8 8.4 4.6
8750 18.9 66.0 215 13 7 9.3 5.1 | 19.9 67.8 210 14 7 8.1 4.4
8500 19.6 67.3 215 13 7 8.2 4.5 | 20.4 68.7 210 14 7 7.8 4.3
8250 20.5 68.9 220 11 6 8.1 4.4 | 21.0 69.8 210 14 7 7.9 4.3
8000 21.3 70.3 220 11 6 11.4 6.3 | 21.6 70.9 205 13 7 8.2 4.5
7750 22.0 71.6 220 11 6 8.0 4.4 | 22.1 71.8 200 12 6 7.7 4.2
7500 22.4 72.3 225 10 5 4.7 2.6 | 22.7 72.9 200 11 6 7.0 3.8
7250 22.8 73.0 225 9 5 7.2 4.0 | 23.2 73.8 200 11 6 7.2 4.0
7000 23.5 74.3 225 8 4 11.5 6.3 | 23.7 74.7 195 10 5 7.9 4.4
6750 24.3 75.7 225 8 4 8.8 4.8 | 24.3 75.7 190 9 5 7.4 4.1
6500 24.7 76.5 230 7 4 5.3 2.9 | 24.7 76.5 185 8 4 6.7 3.7
6250 25.0 77.0 235 6 3 6.2 3.4 | 25.2 77.4 175 7 4 6.8 3.7
6000 25.5 77.9 240 6 3 10.3 5.6 | 25.7 78.3 170 7 3 7.2 4.0
5750 26.5 79.7 240 5 3 17.5 9.6 | 26.2 79.2 165 5 3 9.6 5.2
5500 27.3 81.1 245 4 2 1.5 0.9 | 26.8 80.2 150 5 2 10.5 5.8
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
________________________________________________________________________________
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.
042613