Soaring Guidance
Issued by NWS Grand Junction, CO
Issued by NWS Grand Junction, CO
560
UXUS97 KGJT 221306
SRGGJT
Soaring Forecast
National Weather Service Grand Junction, Colorado
606 AM MST Friday, November 22, 2024
This forecast is for Friday, November 22, 2024:
If the trigger temperature of 62.4 F/16.9 C is reached...then
Thermal Soaring Index....................... Fair
Maximum rate of lift........................ 234 ft/min (1.2 m/s)
Maximum height of thermals.................. 7444 ft MSL (2605 ft AGL)
Forecast maximum temperature................... 54.0 F/12.7 C
Time of trigger temperature.................... None
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................. 7052 ft MSL (2213 ft AGL)
Thermal soaring outlook for Saturday 11/23..... Fair
Wave Soaring Index............................. Not available
Remarks...
Sunrise/Sunset.................... 07:05:54 / 16:55:01 MST
Total possible sunshine........... 9 hr 49 min 7 sec (589 min 7 sec)
Altitude of sun at 12:00:27 MST... 30.53 degrees
Upper air data from rawinsonde observation taken on 11/22/2024 at 0500 MST
Freezing level.................. 5039 ft MSL (200 ft AGL)
Additional freezing level....... 13267 ft MSL (8428 ft AGL)
Convective condensation level... 24384 ft MSL (19545 ft AGL)
Lifted condensation level....... 16213 ft MSL (11374 ft AGL)
Lifted index.................... +16.1
K index......................... -21.2
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 -64.9 -84.8 280 73 38 -2.2 -1.2 91.9 197.4 45.4 M M
45000 -64.2 -83.6 275 65 34 2.1 1.1 68.3 155.0 34.3 M M
40000 -62.8 -81.0 260 39 20 8.6 4.7 47.4 117.3 23.1 M M
38000 -58.2 -72.8 265 45 23 6.4 3.5 45.5 114.0 22.5 M M
36000 -55.1 -67.2 260 44 23 8.8 4.8 41.6 106.8 20.3 M M
34000 -48.8 -55.8 275 42 22 8.5 4.7 41.2 106.2 20.7 M M
32000 -43.7 -46.7 275 37 19 8.1 4.5 40.2 104.3 20.5 M M
30000 -39.0 -38.2 290 25 13 8.5 4.7 38.6 101.5 19.8 M M
29000 -36.3 -33.3 290 24 12 8.0 4.4 38.2 100.8 19.7 M M
28000 -33.6 -28.5 285 23 12 9.9 5.4 38.0 100.4 19.8 M M
27000 -31.0 -23.8 280 25 13 8.5 4.7 37.5 99.4 19.7 M M
26000 -28.7 -19.7 270 27 14 6.9 3.8 36.8 98.2 19.3 M M
25000 -26.6 -15.9 280 34 17 7.1 3.9 35.7 96.3 18.7 M M
24000 -24.2 -11.6 280 35 18 8.7 4.8 35.0 95.0 18.3 M M
23000 -21.6 -6.9 275 36 19 8.7 4.8 34.6 94.4 18.2 M M
22000 -19.0 -2.2 270 33 17 9.4 5.2 34.2 93.6 18.1 M M
21000 -16.5 2.3 265 29 15 6.8 3.7 33.8 92.9 18.0 M M
20000 -14.5 5.9 255 26 13 4.7 2.6 32.7 90.9 17.3 M M
19500 -13.6 7.5 260 26 13 7.9 4.3 32.0 89.7 16.8 M M
19000 -13.2 8.2 260 26 13 -0.6 -0.3 30.8 87.5 15.8 M M
18500 -11.8 10.8 265 26 13 9.7 5.3 29.9 85.8 15.1 M M
18000 -10.5 13.1 265 26 13 7.8 4.3 29.7 85.5 15.0 M M
17500 -9.4 15.1 265 27 14 7.7 4.2 29.3 84.8 14.8 M M
17000 -8.3 17.1 265 26 14 6.1 3.3 28.9 84.0 14.5 M M
16500 -7.5 18.5 270 24 12 5.9 3.2 28.2 82.7 13.9 M M
16000 -6.5 20.3 275 23 12 7.5 4.1 27.7 81.8 13.5 M M
15500 -5.4 22.3 275 24 12 8.3 4.6 27.4 81.3 13.3 M M
15000 -4.1 24.6 270 24 12 8.2 4.5 27.1 80.8 13.1 M M
14500 -2.9 26.8 265 23 12 8.6 4.7 26.9 80.4 13.0 M M
14000 -1.6 29.1 255 22 11 8.3 4.5 26.7 80.0 12.9 M M
13500 -0.4 31.3 260 22 11 7.2 3.9 26.3 79.3 12.6 M M
13000 0.7 33.3 255 24 12 8.7 4.8 25.9 78.6 12.4 M M
12500 1.3 34.3 245 22 11 1.4 0.7 24.8 76.6 11.5 M M
12000 2.2 36.0 245 20 10 6.1 3.4 24.2 75.6 11.1 M M
11500 2.9 37.2 235 22 11 -1.9 -1.0 23.4 74.1 10.4 M M
11000 3.0 37.4 245 23 12 1.8 1.0 21.9 71.4 9.0 M M
10500 2.9 37.2 240 23 12 2.3 1.3 20.3 68.5 7.6 M M
10250 3.0 37.4 230 20 10 0.1 0.1 19.6 67.3 6.9 M M
10000 3.0 37.4 215 12 6 1.0 0.6 18.9 65.9 6.2 M M
9750 3.2 37.8 215 12 6 4.3 2.4 18.3 64.9 5.7 M M
9500 3.6 38.5 210 12 6 5.6 3.0 17.9 64.3 5.4 M M
9250 4.0 39.2 195 14 7 5.2 2.9 17.6 63.7 5.0 M M
9000 4.4 39.9 185 16 8 5.3 2.9 17.2 63.0 4.7 M M
8750 4.8 40.6 180 16 8 5.3 2.9 16.9 62.4 4.4 M M
8500 5.1 41.2 175 15 8 5.3 2.9 16.5 61.8 4.1 M M
8250 5.5 41.9 170 16 8 4.1 2.2 16.2 61.1 3.7 M M
8000 5.8 42.4 165 17 9 7.9 4.3 15.8 60.4 3.3 M M
7750 6.2 43.2 165 17 9 -6.1 -3.3 15.4 59.8 2.9 M M
7500 4.9 40.8 160 19 10 -20.5 -11.3 13.3 56.0 0.9 M M
7250 3.5 38.3 150 14 7 -16.5 -9.0 11.2 52.2 -1.2 254 1.3
7000 2.5 36.5 130 11 5 -7.3 -4.0 9.4 49.0 -3.0 277 1.4
6750 2.5 36.5 120 9 5 5.3 2.9 8.7 47.6 -3.7 269 1.4
6500 2.9 37.2 105 8 4 5.1 2.8 8.4 47.1 -4.0 249 1.3
6250 3.2 37.8 110 7 4 2.2 1.2 7.9 46.2 -4.5 234 1.2
6000 3.4 38.1 095 5 3 5.2 2.8 7.4 45.3 -5.0 220 1.1
5750 3.6 38.5 110 6 3 -3.9 -2.1 6.9 44.4 -5.6 206 1.0
5500 2.8 37.0 145 10 5 -11.9 -6.5 5.4 41.7 -7.1 223 1.1
5250 2.0 35.6 135 11 6 -11.8 -6.5 3.8 38.9 -8.7 241 1.2
5000 0.5 32.9 135 8 4 -28.8 -15.8 1.7 35.0 -10.9 276 1.4
* * * * * * Numerical weather prediction model forecast data valid * * * * * *
11/22/2024 at 0800 MST | 11/22/2024 at 1100 MST
|
CAPE... 0.0 LI... +8.2 | CAPE... 0.0 LI... +8.3
CINH... -0.0 K Index... -18.4 | CINH... -0.1 K Index... -18.9
|
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 -66.2 -87.2 280 61 31 0.9 0.5 | -66.0 -86.8 275 60 31 0.4 0.2
45000 -64.7 -84.5 280 66 34 2.0 1.1 | -65.3 -85.5 275 67 35 2.2 1.2
40000 -61.7 -79.1 275 43 22 1.4 0.8 | -62.0 -79.6 275 46 23 1.5 0.9
38000 -58.1 -72.6 275 39 20 6.5 3.6 | -58.3 -72.9 275 40 21 6.9 3.8
36000 -54.2 -65.6 280 36 18 6.5 3.6 | -54.1 -65.4 275 36 18 6.9 3.8
34000 -49.6 -57.3 280 33 17 8.6 4.7 | -49.5 -57.1 275 33 17 8.4 4.6
32000 -44.4 -47.9 280 29 15 8.6 4.7 | -44.5 -48.1 275 32 16 8.4 4.6
30000 -39.4 -38.9 280 26 14 8.1 4.5 | -39.4 -38.9 270 30 15 8.4 4.6
29000 -37.0 -34.6 280 26 13 8.1 4.5 | -36.9 -34.4 265 28 15 8.4 4.6
28000 -34.6 -30.3 280 25 13 8.1 4.5 | -34.4 -29.9 265 27 14 8.4 4.6
27000 -32.1 -25.8 280 26 13 7.9 4.4 | -31.9 -25.4 265 27 14 7.7 4.2
26000 -29.2 -20.6 280 28 14 7.9 4.4 | -29.1 -20.4 270 28 14 7.7 4.2
25000 -26.8 -16.2 280 29 15 8.0 4.4 | -26.8 -16.2 270 29 15 7.7 4.2
24000 -24.3 -11.7 275 30 15 8.4 4.6 | -24.3 -11.7 270 29 15 8.4 4.6
23000 -21.8 -7.2 275 30 15 8.4 4.6 | -21.8 -7.2 270 28 15 8.5 4.6
22000 -19.3 -2.7 275 30 15 8.4 4.6 | -19.3 -2.7 270 28 14 8.5 4.7
21000 -16.9 1.6 275 30 15 7.9 4.3 | -16.8 1.8 270 27 14 8.1 4.4
20000 -14.5 5.9 270 30 15 7.9 4.3 | -14.4 6.1 265 27 14 8.1 4.4
19500 -13.4 7.9 270 29 15 7.9 4.3 | -13.2 8.2 265 26 13 8.1 4.4
19000 -12.2 10.0 270 29 15 7.6 4.2 | -11.9 10.6 265 26 13 7.6 4.2
18500 -11.1 12.0 270 29 15 7.4 4.1 | -10.9 12.4 265 26 13 7.3 4.0
18000 -10.0 14.0 270 29 15 7.5 4.1 | -9.8 14.4 265 26 13 7.3 4.0
17500 -8.9 16.0 270 28 15 6.8 3.8 | -8.7 16.3 265 26 13 6.5 3.6
17000 -7.9 17.8 270 28 14 6.9 3.8 | -7.8 18.0 265 26 13 6.6 3.6
16500 -6.9 19.6 265 27 14 6.6 3.6 | -6.8 19.8 265 26 14 6.4 3.5
16000 -5.9 21.4 265 27 14 6.4 3.5 | -5.9 21.4 265 26 14 6.3 3.4
15500 -4.9 23.2 265 26 13 6.4 3.5 | -4.9 23.2 265 26 14 6.2 3.4
15000 -4.0 24.8 265 26 13 6.4 3.5 | -4.0 24.8 260 26 13 6.2 3.4
14500 -3.0 26.6 260 25 13 6.4 3.5 | -3.1 26.4 260 25 13 6.2 3.4
14000 -2.1 28.2 260 24 12 6.1 3.3 | -2.1 28.2 260 25 13 6.2 3.4
13500 -1.2 29.8 260 23 12 6.2 3.4 | -1.2 29.8 260 24 12 6.3 3.4
13000 -0.3 31.5 255 22 11 5.3 2.9 | -0.3 31.5 255 23 12 5.4 3.0
12500 0.5 32.9 250 21 11 5.5 3.0 | 0.5 32.9 255 21 11 5.6 3.0
12000 1.3 34.3 250 20 10 4.1 2.2 | 1.3 34.3 250 20 10 4.2 2.3
11500 1.9 35.4 245 19 10 4.1 2.3 | 1.9 35.4 245 19 10 4.2 2.3
11000 2.4 36.3 240 18 9 2.8 1.5 | 2.4 36.3 240 17 9 2.8 1.5
10500 2.8 37.0 235 16 8 3.0 1.7 | 2.8 37.0 235 16 8 3.0 1.6
10250 3.0 37.4 235 16 8 1.2 0.7 | 3.0 37.4 235 15 8 1.4 0.8
10000 3.0 37.4 230 15 8 0.9 0.5 | 3.1 37.6 235 15 7 1.3 0.7
9750 3.2 37.8 230 14 7 2.7 1.5 | 3.3 37.9 230 13 7 2.9 1.6
9500 3.4 38.1 225 13 7 2.8 1.5 | 3.4 38.1 225 12 6 2.5 1.4
9250 3.6 38.5 215 11 6 0.3 0.2 | 3.6 38.5 220 11 6 2.5 1.4
9000 3.7 38.7 210 10 5 1.3 0.7 | 3.9 39.0 210 9 5 1.4 0.8
8750 3.8 38.8 200 9 5 1.5 0.8 | 4.0 39.2 205 8 4 1.3 0.7
8500 3.9 39.0 195 9 5 1.5 0.8 | 4.2 39.6 200 8 4 2.6 1.4
8250 4.0 39.2 190 9 5 1.9 1.0 | 4.4 39.9 195 8 4 3.5 1.9
8000 4.1 39.4 185 9 4 0.5 0.3 | 4.6 40.3 190 7 4 1.7 0.9
7750 4.0 39.2 180 8 4 0.1 0.1 | 4.6 40.3 185 7 3 0.6 0.3
7500 4.1 39.4 175 8 4 1.3 0.7 | 4.7 40.5 185 6 3 1.5 0.8
7250 4.2 39.6 170 8 4 1.6 0.9 | 4.8 40.6 180 6 3 0.3 0.2
7000 4.3 39.7 165 8 4 0.4 0.2 | 4.9 40.8 180 6 3 4.5 2.5
6750 4.3 39.7 160 6 3 -0.5 -0.3 | 5.4 41.7 175 4 2 6.8 3.7
6500 4.2 39.6 150 5 2 -1.1 -0.6 | 5.8 42.4 180 3 1 4.4 2.4
6250 4.2 39.6 140 4 2 2.1 1.1 | 6.1 43.0 180 2 1 4.8 2.7
6000 4.0 39.2 125 3 2 -12.8 -7.0 | 6.5 43.7 180 1 1 5.6 3.1
5750 1.8 35.2 100 3 1 -44.7 -24.5 | 7.0 44.6 195 1 0 10.7 5.9
5500 -0.1 31.8 060 3 1 26.7 14.6 | 8.1 46.6 000 0 0 18.2 10.0
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
11/22/2024 at 1400 MST | 11/22/2024 at 1700 MST
|
CAPE... 0.0 LI... +7.5 | CAPE... 0.0 LI... +7.0
CINH... -0.1 K Index... -15.7 | CINH... -0.2 K Index... -13.7
|
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 -65.5 -85.9 275 59 30 -0.5 -0.3 | -66.1 -87.0 275 62 32 0.2 0.1
45000 -66.0 -86.8 275 76 39 3.0 1.7 | -65.6 -86.1 270 76 39 2.4 1.3
40000 -61.7 -79.1 275 55 28 2.3 1.2 | -62.2 -80.0 270 61 31 2.4 1.3
38000 -57.8 -72.0 275 50 26 7.1 3.9 | -58.0 -72.4 270 55 29 7.3 4.0
36000 -53.5 -64.3 270 44 23 7.1 3.9 | -53.7 -64.7 265 51 26 7.3 4.0
34000 -48.9 -56.0 270 41 21 8.2 4.5 | -49.0 -56.2 265 47 24 8.3 4.6
32000 -44.0 -47.2 270 40 21 8.2 4.5 | -44.0 -47.2 265 44 23 8.3 4.6
30000 -39.3 -38.7 270 37 19 7.5 4.1 | -39.2 -38.6 265 40 21 7.7 4.2
29000 -37.0 -34.6 265 34 17 7.5 4.1 | -36.9 -34.4 265 38 20 7.7 4.2
28000 -34.8 -30.6 265 30 16 7.5 4.1 | -34.6 -30.3 265 36 19 7.7 4.2
27000 -32.5 -26.5 260 29 15 8.0 4.4 | -32.3 -26.1 265 34 18 7.8 4.3
26000 -30.1 -22.2 260 28 14 8.0 4.4 | -30.0 -22.0 260 33 17 7.8 4.3
25000 -27.1 -16.8 260 28 14 8.0 4.4 | -27.6 -17.7 260 32 17 7.8 4.3
24000 -24.6 -12.3 260 27 14 8.5 4.6 | -24.6 -12.3 255 31 16 8.4 4.6
23000 -22.1 -7.8 260 27 14 8.5 4.6 | -22.1 -7.8 255 31 16 8.4 4.6
22000 -19.5 -3.1 260 27 14 8.5 4.7 | -19.5 -3.1 255 30 16 8.5 4.7
21000 -17.1 1.2 260 27 14 7.9 4.3 | -17.1 1.2 255 30 15 7.7 4.2
20000 -14.7 5.5 260 27 14 7.9 4.3 | -14.8 5.4 255 29 15 7.7 4.2
19500 -13.5 7.7 260 27 14 7.9 4.3 | -13.7 7.3 255 29 15 7.7 4.2
19000 -12.4 9.7 260 27 14 7.5 4.1 | -12.5 9.5 255 28 15 7.5 4.1
18500 -11.3 11.7 260 27 14 7.1 3.9 | -11.5 11.3 260 28 14 7.1 3.9
18000 -10.2 13.6 260 27 14 7.1 3.9 | -10.4 13.3 260 27 14 7.1 3.9
17500 -9.2 15.4 265 27 14 6.8 3.7 | -9.3 15.3 260 26 13 7.1 3.9
17000 -8.2 17.2 265 27 14 6.8 3.7 | -8.3 17.1 260 25 13 7.1 3.9
16500 -7.2 19.0 265 27 14 6.9 3.8 | -7.2 19.0 260 25 13 7.3 4.0
16000 -6.2 20.8 265 27 14 6.9 3.8 | -6.1 21.0 260 24 13 7.4 4.1
15500 -5.1 22.8 265 26 14 6.9 3.8 | -5.0 23.0 265 24 12 7.4 4.0
15000 -4.1 24.6 265 26 13 6.8 3.7 | -4.0 24.8 260 23 12 7.0 3.9
14500 -3.1 26.4 265 25 13 6.8 3.8 | -2.9 26.8 260 22 11 7.1 3.9
14000 -2.1 28.2 265 24 13 6.4 3.5 | -1.9 28.6 260 21 11 6.7 3.7
13500 -1.1 30.0 260 23 12 6.5 3.6 | -0.9 30.4 260 21 11 6.8 3.7
13000 -0.2 31.6 260 22 11 5.5 3.0 | 0.1 32.2 255 20 10 5.6 3.1
12500 0.6 33.1 255 21 11 5.6 3.1 | 0.9 33.6 255 19 10 5.6 3.1
12000 1.4 34.5 250 20 10 4.6 2.5 | 1.8 35.2 250 18 9 5.0 2.7
11500 2.1 35.8 245 18 9 4.6 2.5 | 2.5 36.5 245 17 9 4.9 2.7
11000 2.7 36.9 240 17 9 3.4 1.9 | 3.2 37.8 235 16 8 3.8 2.1
10500 3.2 37.8 235 16 8 3.4 1.9 | 3.7 38.7 230 15 8 3.9 2.1
10250 3.4 38.1 230 15 8 2.5 1.4 | 4.0 39.2 225 14 7 2.2 1.2
10000 3.6 38.5 230 15 8 2.4 1.3 | 4.1 39.4 225 14 7 2.4 1.3
9750 3.8 38.8 230 14 7 3.3 1.8 | 4.4 39.9 220 13 7 4.1 2.3
9500 4.0 39.2 225 12 6 3.0 1.6 | 4.6 40.3 215 13 6 3.8 2.1
9250 4.3 39.7 220 11 6 3.3 1.8 | 4.9 40.8 210 12 6 3.3 1.8
9000 4.5 40.1 215 10 5 3.3 1.8 | 5.1 41.2 205 11 6 2.6 1.4
8750 4.7 40.5 210 9 5 2.6 1.4 | 5.5 41.9 195 10 5 2.8 1.6
8500 4.9 40.8 210 8 4 2.5 1.4 | 5.7 42.3 190 9 5 3.2 1.8
8250 5.3 41.5 200 7 3 2.6 1.4 | 6.0 42.8 185 8 4 3.5 1.9
8000 5.5 41.9 200 6 3 3.0 1.6 | 6.2 43.2 180 8 4 2.6 1.4
7750 5.7 42.3 205 5 3 2.8 1.6 | 6.4 43.5 180 6 3 2.3 1.3
7500 5.9 42.6 210 4 2 2.6 1.4 | 6.5 43.7 180 5 3 2.8 1.5
7250 6.0 42.8 220 3 2 1.4 0.8 | 6.8 44.2 180 5 2 3.0 1.7
7000 6.2 43.2 235 2 1 7.0 3.8 | 7.0 44.6 180 4 2 2.6 1.4
6750 7.0 44.6 260 2 1 9.4 5.2 | 7.2 45.0 190 2 1 3.2 1.7
6500 7.5 45.5 275 2 1 6.5 3.6 | 7.4 45.3 230 1 1 3.6 2.0
6250 8.0 46.4 285 3 1 6.1 3.3 | 7.7 45.9 275 2 1 4.5 2.5
6000 8.5 47.3 295 3 2 10.7 5.9 | 8.0 46.4 295 3 1 0.3 0.2
5750 9.8 49.6 290 3 1 21.5 11.8 | 7.5 45.5 300 2 1 -14.0 -7.7
5500 10.7 51.3 295 3 2 -7.9 -4.4 | 6.2 43.2 295 2 1 -14.6 -8.0
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.
042613