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Soaring Guidance
Issued by NWS Grand Junction, CO
Issued by NWS Grand Junction, CO
000
UXUS97 KGJT 221307
SRGGJT
Soaring Forecast
National Weather Service Grand Junction, Colorado
707 AM MDT Monday, April 22, 2024
This forecast is for Monday, April 22, 2024:
If the trigger temperature of 71.6 F/22.0 C is reached...then
Thermal Soaring Index....................... Excellent
Maximum rate of lift........................ 1575 ft/min (8.0 m/s)
Maximum height of thermals.................. 21267 ft MSL (16428 ft AGL)
Forecast maximum temperature................... 83.0 F/28.8 C
Time of trigger temperature.................... 1100 MDT
Time of overdevelopment........................ 1900 MDT
Middle/high clouds during soaring window....... None
Surface winds during soaring window............ 20 mph or less
Height of the -3 thermal index................. 16841 ft MSL (12002 ft AGL)
Thermal soaring outlook for Tuesday 04/23...... Excellent
Wave Soaring Index............................. Not available
Remarks...
Sunrise/Sunset.................... 06:26:16 / 19:58:43 MDT
Total possible sunshine........... 13 hr 32 min 27 sec (812 min 27 sec)
Altitude of sun at 13:12:29 MDT... 63.30 degrees
Upper air data from rawinsonde observation taken on 04/22/2024 at 0600 MDT
Freezing level.................. 12803 ft MSL (7964 ft AGL)
Convective condensation level... 18383 ft MSL (13544 ft AGL)
Lifted condensation level....... 19286 ft MSL (14447 ft AGL)
Lifted index.................... -1.1
K index......................... +17.6
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 -58.0 -72.4 280 41 21 2.6 1.4 103.5 218.3 42.9 M M
45000 -58.6 -73.5 280 56 29 -7.9 -4.4 77.8 172.1 30.3 M M
40000 -64.7 -84.5 280 57 29 6.3 3.5 44.8 112.7 10.8 M M
38000 -60.7 -77.3 285 53 27 7.6 4.2 42.1 107.7 9.3 M M
36000 -56.3 -69.3 280 47 24 7.8 4.3 40.0 104.0 8.1 M M
34000 -50.6 -59.1 280 49 25 9.0 5.0 38.7 101.7 7.4 M M
32000 -45.7 -50.3 285 48 25 7.2 4.0 37.5 99.4 6.7 M M
30000 -40.8 -41.4 285 42 22 9.1 5.0 36.1 97.1 5.9 M M
29000 -38.1 -36.6 285 42 22 9.0 5.0 35.9 96.6 5.7 M M
28000 -35.5 -31.9 280 38 20 7.3 4.0 35.5 95.9 5.5 M M
27000 -33.3 -27.9 275 39 20 7.1 3.9 34.5 94.1 4.8 M M
26000 -31.1 -24.0 270 43 22 8.6 4.7 33.6 92.4 4.1 M M
25000 -28.4 -19.1 270 43 22 9.2 5.1 33.3 92.0 4.0 M M
24000 -26.5 -15.7 270 40 21 4.4 2.4 32.1 89.8 3.0 M M
23000 -24.9 -12.8 265 36 19 5.1 2.8 30.4 86.8 1.7 M M
22000 -23.1 -9.6 250 31 16 7.7 4.2 29.1 84.3 0.6 M M
21000 -20.9 -5.6 260 30 15 7.6 4.1 28.3 82.9 -0.1 1557 7.9
20000 -18.5 -1.3 275 34 17 9.1 5.0 27.6 81.7 -0.7 1457 7.4
19500 -17.2 1.0 275 33 17 8.3 4.6 27.4 81.3 -0.9 1403 7.1
19000 -16.0 3.2 280 30 15 8.8 4.8 27.1 80.9 -1.1 1351 6.9
18500 -14.3 6.3 280 28 14 7.4 4.1 26.6 79.9 -1.6 1277 6.5
18000 -13.2 8.2 285 30 15 7.5 4.1 26.2 79.2 -2.0 1231 6.3
17500 -12.2 10.0 285 30 16 7.2 3.9 25.8 78.5 -2.5 1185 6.0
17000 -11.2 11.8 280 34 18 6.8 3.7 25.4 77.6 -2.9 1140 5.8
16500 -10.0 14.0 275 32 17 9.4 5.2 25.0 77.1 -3.3 1091 5.5
16000 -8.6 16.5 280 31 16 9.6 5.3 25.0 77.0 -3.3 1034 5.3
15500 -7.2 19.0 275 32 16 9.9 5.5 25.0 77.0 -3.4 976 5.0
15000 -5.7 21.7 275 32 17 9.2 5.1 25.0 77.1 -3.4 917 4.7
14500 -4.4 24.1 265 33 17 8.8 4.8 24.9 76.8 -3.5 863 4.4
14000 -3.1 26.4 265 32 16 8.8 4.8 24.8 76.6 -3.7 808 4.1
13500 -1.7 28.9 260 32 16 8.8 4.8 24.6 76.4 -3.8 754 3.8
13000 -0.4 31.3 250 29 15 8.8 4.8 24.5 76.1 -4.0 700 3.6
12500 0.9 33.6 250 29 15 8.8 4.8 24.3 75.8 -4.1 646 3.3
12000 2.2 36.0 250 28 14 8.8 4.8 24.2 75.5 -4.3 591 3.0
11500 3.5 38.3 255 28 14 8.8 4.8 24.0 75.2 -4.5 537 2.7
11000 4.8 40.6 250 27 14 8.8 4.8 23.8 74.9 -4.7 483 2.5
10500 6.2 43.2 255 28 14 8.9 4.9 23.7 74.6 -4.9 429 2.2
10250 6.8 44.2 255 27 14 8.3 4.5 23.6 74.4 -5.0 401 2.0
10000 7.4 45.3 255 27 14 7.2 4.0 23.4 74.1 -5.1 377 1.9
9750 7.9 46.2 255 25 13 7.1 3.9 23.2 73.8 -5.3 353 1.8
9500 8.5 47.3 250 23 12 7.1 3.9 23.0 73.4 -5.6 330 1.7
9250 9.0 48.2 250 21 11 7.1 3.9 22.8 73.0 -5.8 306 1.6
9000 9.5 49.1 245 19 10 7.1 3.9 22.6 72.7 -5.9 283 1.4
8750 10.1 50.2 240 18 9 7.1 3.9 22.4 72.3 -6.2 259 1.3
8500 10.6 51.1 240 18 9 7.1 3.9 22.2 72.0 -6.4 236 1.2
8250 11.2 52.2 245 16 8 7.1 3.9 22.0 71.6 -6.6 212 1.1
8000 11.7 53.1 240 13 7 7.1 3.9 21.8 71.2 -6.8 189 1.0
7750 12.2 54.0 245 12 6 7.1 3.9 21.6 70.8 -7.0 165 0.8
7500 12.8 55.0 250 9 5 7.1 3.9 21.4 70.5 -7.2 142 0.7
7250 13.3 55.9 245 6 3 7.1 3.9 21.2 70.1 -7.4 118 0.6
7000 13.8 56.8 170 9 5 7.2 3.9 21.0 69.7 -7.7 95 0.5
6750 14.4 57.9 170 11 6 7.1 3.9 20.7 69.3 -7.9 71 0.4
6500 14.9 58.8 165 14 7 7.3 4.0 20.5 69.0 -8.1 48 0.2
6250 15.4 59.7 160 17 9 6.5 3.6 20.3 68.6 -8.3 24 0.1
6000 15.6 60.1 160 20 10 -4.9 -2.7 19.8 67.6 -9.0 13 0.1
5750 14.8 58.6 160 22 11 -12.4 -6.8 18.2 64.7 -10.5 30 0.2
5500 13.9 57.0 160 21 11 -10.4 -5.7 16.6 61.9 -12.1 47 0.2
5250 13.1 55.6 155 18 9 -10.9 -6.0 15.1 59.1 -13.7 65 0.3
5000 12.3 54.1 145 14 7 -11.1 -6.1 13.5 56.3 -15.3 82 0.4
* * * * * * Numerical weather prediction model forecast data valid * * * * * *
04/22/2024 at 0900 MDT | 04/22/2024 at 1200 MDT
|
CAPE... 0.0 LI... -0.1 | CAPE... +7.9 LI... -0.1
CINH... -0.1 K Index... +18.7 | CINH... -7.9 K Index... +18.1
|
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 -58.5 -73.3 290 48 25 0.3 0.1 | -58.9 -74.0 290 51 26 0.1 0.1
45000 -58.3 -72.9 290 51 26 -3.1 -1.7 | -58.9 -74.0 290 55 28 -2.6 -1.5
40000 -62.8 -81.0 285 55 28 -3.0 -1.6 | -62.4 -80.3 285 58 30 -2.4 -1.3
38000 -60.4 -76.7 285 54 28 7.7 4.2 | -60.0 -76.0 285 58 30 7.6 4.2
36000 -55.8 -68.4 280 52 27 7.7 4.2 | -55.5 -67.9 285 57 29 7.6 4.2
34000 -50.6 -59.1 280 50 26 7.9 4.3 | -50.3 -58.5 280 55 28 7.8 4.3
32000 -45.8 -50.4 275 49 25 7.9 4.3 | -45.6 -50.1 280 52 27 7.8 4.3
30000 -41.1 -42.0 280 48 25 8.0 4.4 | -41.0 -41.8 280 50 26 7.8 4.3
29000 -38.7 -37.7 280 47 24 8.0 4.4 | -38.6 -37.5 280 49 25 7.8 4.3
28000 -36.3 -33.3 280 46 24 8.0 4.4 | -36.3 -33.3 280 49 25 7.8 4.3
27000 -33.9 -29.0 280 45 23 7.7 4.2 | -33.9 -29.0 280 48 24 7.9 4.3
26000 -31.6 -24.9 280 44 22 7.8 4.3 | -31.6 -24.9 280 45 23 7.9 4.3
25000 -29.3 -20.7 275 42 22 7.8 4.3 | -29.2 -20.6 280 43 22 7.9 4.3
24000 -27.0 -16.6 275 40 21 6.5 3.6 | -26.9 -16.4 280 41 21 7.1 3.9
23000 -25.2 -13.4 275 38 19 6.3 3.5 | -24.8 -12.6 275 39 20 6.9 3.8
22000 -23.3 -9.9 270 35 18 6.3 3.5 | -22.8 -9.0 275 38 19 6.9 3.8
21000 -20.9 -5.6 270 33 17 7.0 3.8 | -20.3 -4.5 270 35 18 6.1 3.3
20000 -18.8 -1.8 265 31 16 7.1 3.9 | -18.5 -1.3 265 33 17 6.2 3.4
19500 -17.8 -0.0 265 30 15 7.1 3.9 | -17.7 0.1 265 32 16 6.3 3.4
19000 -16.8 1.8 265 29 15 7.5 4.1 | -16.8 1.8 260 31 16 6.8 3.7
18500 -15.6 3.9 265 29 15 8.5 4.7 | -15.6 3.9 260 30 15 8.4 4.6
18000 -14.3 6.3 265 28 14 8.5 4.6 | -14.4 6.1 260 29 15 8.3 4.6
17500 -13.1 8.4 265 28 14 8.7 4.8 | -13.2 8.2 255 29 15 8.7 4.8
17000 -11.8 10.8 270 27 14 8.8 4.8 | -11.9 10.6 255 29 15 8.8 4.8
16500 -10.5 13.1 270 27 14 8.9 4.9 | -10.6 12.9 260 28 14 8.8 4.8
16000 -9.2 15.4 270 27 14 9.0 5.0 | -9.3 15.3 260 28 14 8.8 4.8
15500 -7.8 18.0 270 27 14 9.1 5.0 | -8.0 17.6 260 27 14 8.8 4.9
15000 -6.5 20.3 270 27 14 9.3 5.1 | -6.6 20.1 260 27 14 9.3 5.1
14500 -5.1 22.8 270 27 14 9.3 5.1 | -5.2 22.6 260 26 13 9.3 5.1
14000 -3.7 25.3 270 27 14 9.3 5.1 | -3.9 25.0 260 26 13 9.4 5.1
13500 -2.3 27.9 270 27 14 9.3 5.1 | -2.5 27.5 265 25 13 9.4 5.2
13000 -0.9 30.4 270 26 14 9.2 5.0 | -1.1 30.0 265 25 13 9.3 5.1
12500 0.4 32.7 270 26 13 9.2 5.0 | 0.3 32.5 265 24 12 9.3 5.1
12000 1.8 35.2 270 25 13 8.9 4.9 | 1.7 35.1 265 23 12 9.2 5.1
11500 3.1 37.6 265 25 13 8.9 4.9 | 3.1 37.6 265 22 12 9.3 5.1
11000 4.4 39.9 265 24 13 7.2 4.0 | 4.4 39.9 265 22 11 7.9 4.3
10500 5.3 41.5 265 24 12 5.6 3.1 | 5.5 41.9 265 21 11 6.3 3.5
10250 5.8 42.4 265 23 12 9.9 5.5 | 6.0 42.8 265 21 11 11.3 6.2
10000 6.7 44.1 260 22 11 10.2 5.6 | 7.1 44.8 265 20 10 11.8 6.5
9750 7.2 45.0 260 21 11 5.8 3.2 | 7.7 45.9 260 19 10 7.0 3.8
9500 7.7 45.9 255 20 10 7.4 4.1 | 8.3 46.9 260 19 10 8.8 4.8
9250 8.2 46.8 255 19 10 5.2 2.8 | 8.9 48.0 260 18 9 6.3 3.4
9000 8.6 47.5 255 20 10 5.4 2.9 | 9.3 48.7 260 17 9 6.7 3.7
8750 9.1 48.4 255 18 9 7.3 4.0 | 9.9 49.8 260 16 8 9.1 5.0
8500 9.6 49.3 250 17 9 7.1 3.9 | 10.5 50.9 260 15 8 8.8 4.8
8250 10.1 50.2 245 15 8 6.0 3.3 | 11.2 52.2 260 14 7 7.6 4.2
8000 10.9 51.6 245 13 7 5.6 3.1 | 11.7 53.1 265 13 7 7.7 4.2
7750 11.3 52.3 240 11 6 6.3 3.4 | 13.2 55.8 265 12 6 10.9 6.0
7500 11.8 53.2 230 10 5 4.6 2.5 | 13.9 57.0 265 11 6 8.7 4.8
7250 12.0 53.6 225 8 4 3.3 1.8 | 14.5 58.1 270 11 6 7.2 4.0
7000 12.4 54.3 220 7 4 7.0 3.9 | 15.2 59.4 270 11 5 10.9 6.0
6750 13.0 55.4 205 7 4 8.3 4.6 | 16.1 61.0 270 10 5 12.2 6.7
6500 13.5 56.3 195 7 3 5.6 3.1 | 16.9 62.4 270 10 5 10.6 5.8
6250 13.9 57.0 185 6 3 4.8 2.6 | 17.7 63.9 275 9 5 10.8 5.9
6000 14.3 57.7 170 5 3 6.1 3.4 | 18.5 65.3 275 9 5 8.2 4.5
5750 14.9 58.8 175 5 3 12.0 6.6 | 19.1 66.4 270 9 4 13.1 7.2
5500 16.3 61.3 160 4 2 27.4 15.1 | 22.0 71.6 280 8 4 81.2 44.5
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
04/22/2024 at 1500 MDT | 04/22/2024 at 1800 MDT
|
CAPE... +18.7 LI... +0.2 | CAPE... +11.4 LI... +0.1
CINH... -4.1 K Index... +15.5 | CINH... -4.9 K Index... +17.5
|
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 -58.9 -74.0 290 54 28 0.1 0.1 | -59.3 -74.7 290 56 29 0.3 0.2
45000 -58.8 -73.8 290 57 29 -2.3 -1.2 | -58.9 -74.0 290 62 32 -1.4 -0.8
40000 -61.8 -79.2 295 61 32 -2.0 -1.1 | -60.8 -77.4 290 67 35 -1.2 -0.7
38000 -59.3 -74.7 295 60 31 7.4 4.0 | -57.7 -71.9 290 64 33 7.0 3.9
36000 -54.4 -65.9 290 57 29 7.4 4.0 | -53.5 -64.3 290 58 30 7.0 3.9
34000 -49.9 -57.8 285 55 28 7.6 4.2 | -49.2 -56.6 285 54 28 7.3 4.0
32000 -45.4 -49.7 280 55 28 7.6 4.2 | -44.9 -48.8 280 52 27 7.3 4.0
30000 -40.8 -41.4 275 53 27 7.9 4.3 | -40.4 -40.7 275 49 25 7.7 4.2
29000 -38.4 -37.1 275 51 26 7.9 4.3 | -38.1 -36.6 270 47 24 7.7 4.2
28000 -36.0 -32.8 275 50 26 7.9 4.3 | -35.8 -32.4 270 45 23 7.7 4.3
27000 -33.7 -28.7 275 48 25 7.8 4.3 | -33.5 -28.3 270 43 22 7.3 4.0
26000 -31.3 -24.3 275 45 23 7.8 4.3 | -31.2 -24.2 270 41 21 7.4 4.1
25000 -29.0 -20.2 275 43 22 7.8 4.3 | -29.0 -20.2 270 38 20 7.4 4.1
24000 -26.7 -16.1 275 41 21 7.0 3.9 | -26.8 -16.2 270 36 19 6.9 3.8
23000 -24.1 -11.4 275 37 19 6.9 3.8 | -24.3 -11.7 275 33 17 6.9 3.8
22000 -22.1 -7.8 275 34 18 6.9 3.8 | -22.3 -8.1 275 30 15 7.0 3.8
21000 -20.0 -4.0 275 31 16 7.0 3.9 | -20.2 -4.4 275 28 14 7.7 4.2
20000 -17.9 -0.2 270 29 15 7.1 3.9 | -17.9 -0.2 270 26 13 7.7 4.2
19500 -16.9 1.6 270 27 14 7.2 3.9 | -16.8 1.8 270 25 13 7.7 4.3
19000 -15.9 3.4 270 26 13 7.3 4.0 | -15.6 3.9 270 24 12 7.9 4.4
18500 -14.8 5.4 265 25 13 7.5 4.1 | -14.4 6.1 270 23 12 8.7 4.8
18000 -13.7 7.3 265 25 13 7.4 4.1 | -13.1 8.4 270 23 12 8.7 4.8
17500 -12.5 9.5 260 24 12 8.9 4.9 | -11.8 10.8 265 22 11 8.9 4.9
17000 -11.2 11.8 260 24 12 9.1 5.0 | -10.5 13.1 265 22 11 9.0 4.9
16500 -9.8 14.4 260 24 12 9.1 5.0 | -9.2 15.4 265 22 11 9.1 5.0
16000 -8.5 16.7 260 24 12 9.2 5.0 | -7.8 18.0 265 22 11 9.3 5.1
15500 -7.1 19.2 260 23 12 9.2 5.0 | -6.4 20.5 265 22 11 9.3 5.1
15000 -5.7 21.7 260 23 12 9.3 5.1 | -5.0 23.0 265 21 11 9.4 5.2
14500 -4.3 24.3 260 23 12 9.3 5.1 | -3.6 25.5 265 21 11 9.4 5.2
14000 -2.9 26.8 260 23 12 9.4 5.1 | -2.2 28.0 265 21 11 9.5 5.2
13500 -1.5 29.3 260 23 12 9.4 5.1 | -0.8 30.6 265 21 11 9.5 5.2
13000 -0.1 31.8 260 23 12 9.4 5.2 | 0.6 33.1 260 21 11 9.4 5.2
12500 1.3 34.3 260 23 12 9.4 5.2 | 2.0 35.6 260 21 11 9.4 5.2
12000 2.7 36.9 260 23 12 9.6 5.3 | 3.5 38.3 260 21 11 9.5 5.2
11500 4.1 39.4 260 23 12 9.7 5.3 | 4.9 40.8 265 21 11 9.4 5.2
11000 5.6 42.1 260 22 12 8.6 4.7 | 6.3 43.3 265 20 11 8.6 4.7
10500 6.8 44.2 260 22 11 7.0 3.9 | 7.5 45.5 265 20 10 7.3 4.0
10250 7.3 45.1 260 22 11 11.8 6.5 | 8.1 46.6 265 20 10 11.7 6.4
10000 8.4 47.1 260 22 11 12.8 7.0 | 9.1 48.4 265 20 10 12.0 6.6
9750 9.1 48.4 260 22 11 8.6 4.7 | 9.8 49.6 265 19 10 8.2 4.5
9500 9.8 49.6 260 21 11 10.1 5.5 | 10.5 50.9 265 19 10 8.9 4.9
9250 10.5 50.9 260 21 11 8.3 4.5 | 11.1 52.0 265 19 10 9.9 5.5
9000 11.1 52.0 260 21 11 8.9 4.9 | 11.9 53.4 265 18 9 10.4 5.7
8750 11.9 53.4 260 20 11 10.6 5.8 | 12.7 54.9 265 18 9 9.3 5.1
8500 13.4 56.1 260 19 10 9.2 5.1 | 14.1 57.4 265 18 9 9.1 5.0
8250 14.0 57.2 260 19 10 8.8 4.8 | 14.7 58.5 265 18 9 9.2 5.0
8000 14.8 58.6 260 19 10 10.4 5.7 | 15.5 59.9 265 17 9 9.9 5.4
7750 15.6 60.1 260 18 9 11.0 6.0 | 16.2 61.2 265 17 9 10.2 5.6
7500 16.4 61.5 260 18 9 9.3 5.1 | 17.0 62.6 270 17 9 9.3 5.1
7250 17.0 62.6 260 18 9 8.0 4.4 | 17.6 63.7 270 17 9 8.3 4.6
7000 17.7 63.9 260 18 9 10.6 5.8 | 18.3 64.9 270 17 9 9.8 5.4
6750 18.5 65.3 260 17 9 11.9 6.5 | 19.0 66.2 270 16 8 10.7 5.9
6500 19.4 66.9 260 17 9 11.1 6.1 | 19.8 67.6 270 15 8 10.6 5.8
6250 20.2 68.4 260 17 9 11.6 6.4 | 20.7 69.3 270 15 8 11.3 6.2
6000 21.0 69.8 260 17 9 8.2 4.5 | 21.4 70.5 270 15 8 8.5 4.7
5750 21.6 70.9 260 15 8 12.7 7.0 | 22.0 71.6 270 14 7 8.9 4.9
5500 24.6 76.3 260 14 7 87.6 48.1 | 23.7 74.7 270 12 6 48.2 26.4
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
- National Weather Service
- Bismarck, ND Weather Forecast Office
- 2301 University Drive, Building 27
- Bismarck, ND 58504
- 701-250-4224
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- Page last modified: Sep 19th, 2023 19:10 UTC