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Soaring Guidance
Issued by NWS Grand Junction, CO
Issued by NWS Grand Junction, CO
000
UXUS97 KGJT 251307
SRGGJT
Soaring Forecast
National Weather Service Grand Junction, Colorado
707 AM MDT Thursday, April 25, 2024
This forecast is for Thursday, April 25, 2024:
If the trigger temperature of 67.7 F/19.8 C is reached...then
Thermal Soaring Index....................... Excellent
Maximum rate of lift........................ 1147 ft/min (5.8 m/s)
Maximum height of thermals.................. 18731 ft MSL (13892 ft AGL)
Forecast maximum temperature................... 74.0 F/23.8 C
Time of trigger temperature.................... 0945 MDT
Time of overdevelopment........................ 1500 MDT
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................. 10312 ft MSL (5473 ft AGL)
Thermal soaring outlook for Friday 04/26....... Good
Wave Soaring Index............................. Not available
Remarks...
Sunrise/Sunset.................... 06:22:17 / 20:01:39 MDT
Total possible sunshine........... 13 hr 39 min 22 sec (819 min 22 sec)
Altitude of sun at 13:11:58 MDT... 64.29 degrees
Upper air data from rawinsonde observation taken on 04/25/2024 at 0600 MDT
Freezing level.................. 11825 ft MSL (6986 ft AGL)
Convective condensation level... 17750 ft MSL (12911 ft AGL)
Lifted condensation level....... 18069 ft MSL (13229 ft AGL)
Lifted index.................... +0.4
K index......................... +15.5
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 -51.4 -60.5 235 59 30 3.1 1.7 113.5 236.3 51.7 M M
45000 -52.2 -62.0 240 39 20 -4.4 -2.4 87.6 189.7 39.4 M M
40000 -49.9 -57.8 225 57 29 -5.4 -2.9 67.2 152.9 28.8 M M
38000 -53.7 -64.7 230 61 31 -7.1 -3.9 52.7 126.9 19.8 M M
36000 -53.1 -63.6 230 82 42 3.3 1.8 45.0 112.9 15.0 M M
34000 -50.6 -59.1 225 73 37 7.1 3.9 40.3 104.5 12.0 M M
32000 -46.3 -51.3 225 73 37 7.1 3.9 38.1 100.6 10.8 M M
30000 -41.5 -42.7 225 65 33 6.9 3.8 35.8 96.4 9.3 M M
29000 -39.5 -39.1 225 54 28 5.9 3.2 34.5 94.1 8.5 M M
28000 -37.7 -35.9 220 45 23 6.0 3.3 33.0 91.4 7.4 M M
27000 -35.9 -32.6 215 37 19 6.0 3.3 31.6 88.9 6.4 M M
26000 -34.2 -29.6 210 46 24 5.5 3.0 30.1 86.2 5.3 M M
25000 -32.3 -26.1 215 40 21 8.7 4.8 28.8 83.9 4.4 M M
24000 -29.7 -21.5 220 38 20 8.7 4.7 28.4 83.0 4.0 M M
23000 -27.5 -17.5 210 34 18 3.4 1.8 27.6 81.6 3.4 M M
22000 -25.8 -14.4 210 31 16 9.1 5.0 26.0 78.9 2.2 M M
21000 -23.2 -9.8 205 33 17 8.8 4.8 25.7 78.2 1.9 M M
20000 -20.7 -5.3 200 31 16 7.5 4.1 25.2 77.3 1.5 M M
19500 -19.7 -3.5 200 29 15 5.9 3.2 24.6 76.3 1.0 M M
19000 -18.9 -2.0 200 25 13 6.1 3.3 24.0 75.1 0.4 M M
18500 -18.0 -0.4 195 21 11 6.6 3.6 23.4 74.1 -0.2 1334 6.8
18000 -16.9 1.6 180 19 10 9.2 5.1 23.0 73.5 -0.5 1286 6.5
17500 -15.5 4.1 180 19 10 9.5 5.2 23.0 73.4 -0.5 1229 6.2
17000 -14.0 6.8 185 19 10 9.5 5.2 23.0 73.4 -0.6 1171 6.0
16500 -12.6 9.3 180 16 8 9.6 5.2 23.0 73.3 -0.6 1114 5.7
16000 -10.5 13.1 200 17 9 9.6 5.2 22.9 73.2 -0.7 1029 5.2
15500 -9.1 15.6 215 15 8 9.5 5.2 22.9 73.1 -0.8 971 4.9
15000 -7.7 18.1 250 14 7 9.0 4.9 22.8 73.0 -0.8 914 4.6
14500 -6.5 20.3 250 14 7 7.9 4.3 22.5 72.5 -1.1 865 4.4
14000 -5.4 22.3 260 15 8 8.2 4.5 22.2 72.0 -1.4 815 4.1
13500 -4.1 24.6 255 17 9 8.3 4.6 22.0 71.6 -1.6 763 3.9
13000 -2.9 26.8 260 25 13 8.4 4.6 21.8 71.3 -1.8 711 3.6
12500 -1.6 29.1 255 25 13 8.4 4.6 21.6 70.9 -2.0 658 3.3
12000 -0.3 31.5 250 21 11 8.4 4.6 21.4 70.5 -2.2 606 3.1
11500 0.9 33.6 245 18 9 8.4 4.6 21.1 70.0 -2.5 553 2.8
11000 2.2 36.0 240 16 8 8.4 4.6 20.9 69.6 -2.7 501 2.5
10500 3.4 38.1 240 16 8 8.4 4.6 20.7 69.2 -2.9 449 2.3
10250 4.1 39.4 240 13 7 8.3 4.6 20.5 69.0 -3.0 422 2.1
10000 4.7 40.5 235 11 6 8.8 4.8 20.4 68.8 -3.1 396 2.0
9750 5.4 41.7 225 9 5 9.2 5.0 20.4 68.7 -3.2 368 1.9
9500 6.1 43.0 215 8 4 9.1 5.0 20.3 68.6 -3.2 340 1.7
9250 6.7 44.1 200 7 3 9.1 5.0 20.3 68.5 -3.3 313 1.6
9000 7.4 45.3 180 5 3 9.1 5.0 20.3 68.5 -3.3 285 1.4
8750 8.1 46.6 175 4 2 9.1 5.0 20.2 68.4 -3.4 257 1.3
8500 8.8 47.8 170 3 2 9.1 5.0 20.2 68.3 -3.4 229 1.2
8250 9.5 49.1 155 3 1 9.1 5.0 20.1 68.2 -3.5 201 1.0
8000 10.1 50.2 125 3 2 9.1 5.0 20.1 68.2 -3.5 174 0.9
7750 10.8 51.4 115 4 2 9.1 5.0 20.0 68.1 -3.6 146 0.7
7500 11.5 52.7 105 5 3 9.1 5.0 20.0 68.0 -3.6 118 0.6
7250 12.2 54.0 130 8 4 9.1 5.0 19.9 67.9 -3.7 90 0.5
7000 12.9 55.2 140 11 6 9.1 5.0 19.9 67.8 -3.8 62 0.3
6750 13.5 56.3 135 11 6 9.1 5.0 19.8 67.7 -3.8 35 0.2
6500 14.2 57.6 135 13 7 9.1 5.0 19.8 67.6 -3.9 7 0.0
6250 14.9 58.8 135 14 7 9.0 5.0 19.7 67.5 -4.0 M M
6000 15.6 60.1 140 16 8 9.3 5.1 19.6 67.4 -4.0 M M
5750 16.2 61.2 140 15 8 7.1 3.9 19.6 67.2 -4.1 M M
5500 16.6 61.9 145 14 7 4.8 2.7 19.2 66.6 -4.5 M M
5250 17.0 62.6 140 11 6 6.5 3.6 18.9 66.1 -4.8 M M
5000 17.4 63.3 130 7 4 2.1 1.2 18.6 65.5 -5.2 M M
* * * * * * Numerical weather prediction model forecast data valid * * * * * *
04/25/2024 at 0900 MDT | 04/25/2024 at 1200 MDT
|
CAPE... +0.7 LI... -0.5 | CAPE... +77.2 LI... -0.5
CINH... -11.1 K Index... +22.2 | CINH... -14.3 K Index... +25.4
|
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 -53.1 -63.6 240 48 25 2.7 1.5 | -52.0 -61.6 235 50 26 2.7 1.5
45000 -49.2 -56.6 230 44 23 -1.0 -0.6 | -48.2 -54.8 230 48 25 -0.8 -0.4
40000 -50.4 -58.7 220 49 25 -0.8 -0.4 | -49.3 -56.7 215 45 23 -0.7 -0.4
38000 -50.6 -59.1 220 54 28 0.2 0.1 | -49.5 -57.1 210 47 24 0.0 0.0
36000 -50.5 -58.9 215 62 32 0.2 0.1 | -49.5 -57.1 205 50 26 0.0 0.0
34000 -49.8 -57.6 215 67 34 5.2 2.9 | -49.1 -56.4 205 52 27 3.8 2.1
32000 -46.8 -52.2 215 62 32 5.0 2.7 | -47.1 -52.8 205 47 24 3.5 1.9
30000 -43.6 -46.5 215 55 28 6.8 3.7 | -44.8 -48.6 205 41 21 6.3 3.5
29000 -41.6 -42.9 215 50 26 6.7 3.7 | -43.0 -45.4 205 36 19 6.0 3.3
28000 -39.6 -39.3 215 45 23 6.7 3.7 | -41.2 -42.2 210 31 16 6.0 3.3
27000 -37.6 -35.7 215 40 21 6.8 3.8 | -39.4 -38.9 210 26 13 6.1 3.3
26000 -35.4 -31.7 215 39 20 7.4 4.0 | -37.2 -35.0 210 24 12 7.7 4.2
25000 -33.2 -27.8 215 37 19 7.4 4.0 | -34.9 -30.8 210 23 12 7.7 4.2
24000 -30.4 -22.7 215 35 18 7.1 3.9 | -32.6 -26.7 210 22 11 7.7 4.2
23000 -28.4 -19.1 210 31 16 6.8 3.8 | -29.7 -21.5 210 19 10 7.9 4.3
22000 -26.3 -15.3 210 26 13 6.9 3.8 | -27.4 -17.3 210 17 9 7.9 4.3
21000 -24.3 -11.7 210 22 11 7.3 4.0 | -25.0 -13.0 205 15 8 8.4 4.6
20000 -22.1 -7.8 205 20 10 7.4 4.1 | -22.5 -8.5 205 14 7 8.5 4.7
19500 -21.0 -5.8 205 19 10 7.4 4.1 | -21.2 -6.2 205 14 7 8.5 4.7
19000 -19.9 -3.8 205 18 9 7.4 4.1 | -20.0 -4.0 205 13 7 8.5 4.7
18500 -18.8 -1.8 200 17 9 8.2 4.5 | -18.7 -1.7 200 13 7 8.4 4.6
18000 -17.6 0.3 200 16 8 8.4 4.6 | -17.5 0.5 200 13 6 8.3 4.6
17500 -16.3 2.7 200 15 8 8.5 4.6 | -16.3 2.7 205 12 6 8.3 4.5
17000 -15.1 4.8 200 15 8 8.6 4.7 | -15.1 4.8 205 12 6 7.9 4.4
16500 -13.8 7.2 200 14 7 8.6 4.7 | -13.9 7.0 205 12 6 8.0 4.4
16000 -12.5 9.5 205 13 7 8.8 4.8 | -12.8 9.0 205 12 6 8.0 4.4
15500 -11.3 11.7 205 13 7 8.8 4.8 | -11.6 11.1 210 12 6 8.1 4.4
15000 -10.0 14.0 205 12 6 8.8 4.8 | -10.4 13.3 210 12 6 8.2 4.5
14500 -8.7 16.3 210 12 6 8.8 4.8 | -9.2 15.4 210 12 6 8.3 4.5
14000 -7.4 18.7 210 11 6 8.8 4.8 | -8.0 17.6 215 12 6 8.3 4.6
13500 -6.1 21.0 215 11 5 8.8 4.8 | -6.7 19.9 215 12 6 8.4 4.6
13000 -4.8 23.4 220 10 5 8.7 4.8 | -5.5 22.1 215 12 6 8.5 4.7
12500 -3.5 25.7 225 10 5 8.5 4.7 | -4.2 24.4 220 12 6 9.0 4.9
12000 -2.2 28.0 230 9 5 8.5 4.7 | -2.8 27.0 220 12 6 9.0 4.9
11500 -0.9 30.4 235 9 5 8.7 4.8 | -1.5 29.3 225 12 6 9.2 5.1
11000 0.4 32.7 235 9 5 8.4 4.6 | -0.1 31.8 225 12 6 9.1 5.0
10500 1.5 34.7 240 9 5 6.5 3.5 | 1.2 34.2 230 11 6 7.5 4.1
10250 2.0 35.6 245 9 4 8.5 4.7 | 1.8 35.2 230 11 6 9.5 5.2
10000 2.7 36.9 240 9 5 10.6 5.8 | 2.6 36.7 230 12 6 11.8 6.5
9750 3.5 38.3 240 9 5 8.6 4.7 | 3.4 38.1 230 12 6 10.0 5.5
9500 4.1 39.4 245 9 5 7.6 4.2 | 4.1 39.4 235 11 6 8.8 4.8
9250 4.6 40.3 245 9 5 7.6 4.2 | 4.8 40.6 235 11 6 9.0 5.0
9000 5.2 41.4 250 9 5 8.6 4.7 | 5.5 41.9 240 11 6 10.3 5.7
8750 5.9 42.6 240 9 4 8.4 4.6 | 6.3 43.3 235 12 6 10.3 5.7
8500 7.0 44.6 235 8 4 7.5 4.1 | 7.7 45.9 240 11 6 9.6 5.3
8250 7.6 45.7 235 8 4 7.5 4.1 | 8.4 47.1 240 11 6 9.1 5.0
8000 8.1 46.6 240 8 4 7.8 4.3 | 9.1 48.4 245 11 5 9.4 5.2
7750 8.7 47.7 235 8 4 8.1 4.4 | 9.8 49.6 245 11 5 10.0 5.5
7500 9.3 48.7 230 7 4 7.7 4.2 | 10.6 51.1 245 10 5 9.6 5.3
7250 9.9 49.8 225 8 4 6.9 3.8 | 11.2 52.2 245 10 5 7.5 4.1
7000 10.4 50.7 230 8 4 8.1 4.4 | 11.8 53.2 250 10 5 8.8 4.8
6750 11.1 52.0 220 8 4 9.3 5.1 | 12.6 54.7 250 10 5 11.2 6.2
6500 11.8 53.2 210 7 4 8.9 4.9 | 13.4 56.1 250 10 5 10.1 5.5
6250 12.5 54.5 210 7 4 9.4 5.2 | 14.1 57.4 255 10 5 10.1 5.5
6000 13.2 55.8 215 6 3 8.0 4.4 | 14.8 58.6 260 10 5 7.8 4.3
5750 13.7 56.7 210 6 3 9.7 5.3 | 15.4 59.7 255 9 5 11.6 6.4
5500 15.3 59.5 205 5 2 40.3 22.1 | 17.8 64.0 260 9 4 64.8 35.6
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
04/25/2024 at 1500 MDT | 04/25/2024 at 1800 MDT
|
CAPE... +128.4 LI... -0.2 | CAPE... +53.1 LI... -0.3
CINH... -33.2 K Index... +21.4 | CINH... -34.0 K Index... +17.2
|
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 -51.3 -60.3 235 47 24 2.0 1.1 | -50.7 -59.3 240 41 21 2.1 1.1
45000 -48.3 -54.9 235 45 23 0.2 0.1 | -47.7 -53.9 240 39 20 0.3 0.1
40000 -48.2 -54.8 220 38 20 0.1 0.0 | -47.8 -54.0 240 26 14 -0.1 -0.0
38000 -48.4 -55.1 215 35 18 -0.8 -0.4 | -48.3 -54.9 240 21 11 -2.2 -1.2
36000 -49.0 -56.2 205 30 15 -0.8 -0.4 | -49.7 -57.5 235 13 7 -2.1 -1.2
34000 -49.3 -56.7 200 25 13 1.2 0.7 | -50.8 -59.4 220 7 3 1.5 0.8
32000 -48.6 -55.5 190 15 8 1.2 0.6 | -49.7 -57.5 145 6 3 1.8 1.0
30000 -47.5 -53.5 165 7 4 8.7 4.8 | -48.2 -54.8 115 10 5 9.0 4.9
29000 -45.1 -49.2 165 7 4 8.0 4.4 | -45.7 -50.3 120 7 4 8.6 4.7
28000 -42.7 -44.9 170 7 4 8.0 4.4 | -43.1 -45.6 135 5 3 8.6 4.7
27000 -40.3 -40.5 170 7 4 8.0 4.4 | -40.5 -40.9 165 3 2 8.6 4.7
26000 -37.7 -35.9 175 8 4 8.6 4.7 | -37.9 -36.2 200 4 2 8.9 4.9
25000 -35.2 -31.4 185 9 5 8.6 4.7 | -35.2 -31.4 215 6 3 8.9 4.9
24000 -32.6 -26.7 195 10 5 8.6 4.7 | -32.6 -26.7 225 7 4 9.0 4.9
23000 -29.6 -21.3 200 12 6 8.2 4.5 | -30.1 -22.2 230 8 4 7.9 4.3
22000 -27.1 -16.8 205 13 7 8.2 4.5 | -27.2 -17.0 235 9 5 7.9 4.3
21000 -24.7 -12.5 210 14 7 8.1 4.4 | -24.8 -12.6 240 9 5 8.0 4.4
20000 -22.3 -8.1 215 15 7 8.1 4.4 | -22.5 -8.5 245 11 5 8.0 4.4
19500 -21.1 -6.0 220 15 8 8.1 4.4 | -21.3 -6.3 250 11 6 8.0 4.4
19000 -20.0 -4.0 220 15 8 8.1 4.4 | -20.1 -4.2 250 12 6 8.0 4.4
18500 -18.8 -1.8 225 15 8 7.9 4.3 | -18.9 -2.0 255 12 6 8.3 4.5
18000 -17.6 0.3 230 16 8 7.8 4.3 | -17.6 0.3 255 13 7 8.5 4.6
17500 -16.5 2.3 230 16 8 7.8 4.3 | -16.4 2.5 255 14 7 8.5 4.7
17000 -15.3 4.5 235 16 8 7.8 4.3 | -15.1 4.8 255 15 8 9.0 4.9
16500 -14.2 6.4 235 16 8 7.8 4.3 | -13.8 7.2 255 16 8 9.0 4.9
16000 -13.0 8.6 240 16 8 8.0 4.4 | -12.4 9.7 255 17 9 9.0 5.0
15500 -11.8 10.8 240 16 8 8.0 4.4 | -11.1 12.0 255 17 9 9.0 5.0
15000 -10.6 12.9 245 16 8 8.2 4.5 | -9.8 14.4 255 18 9 9.1 5.0
14500 -9.4 15.1 245 17 9 8.4 4.6 | -8.4 16.9 255 18 9 9.1 5.0
14000 -8.1 17.4 250 17 9 8.5 4.7 | -7.1 19.2 255 19 10 9.2 5.0
13500 -6.8 19.8 250 17 9 8.8 4.8 | -5.7 21.7 255 19 10 9.4 5.2
13000 -5.5 22.1 250 17 9 8.8 4.8 | -4.3 24.3 255 19 10 9.4 5.1
12500 -4.2 24.4 250 17 9 9.0 5.0 | -2.9 26.8 255 19 10 9.5 5.2
12000 -2.9 26.8 250 17 9 9.0 5.0 | -1.5 29.3 255 19 10 9.5 5.2
11500 -1.5 29.3 250 17 9 9.1 5.0 | -0.1 31.8 255 19 10 9.3 5.1
11000 -0.2 31.6 250 17 9 9.0 4.9 | 1.3 34.3 255 19 10 9.4 5.2
10500 1.0 33.8 250 17 9 6.6 3.6 | 2.6 36.7 255 19 10 7.3 4.0
10250 1.5 34.7 250 17 9 9.0 4.9 | 3.2 37.8 255 19 10 9.1 5.0
10000 2.3 36.1 250 17 9 12.3 6.7 | 4.0 39.2 255 19 10 11.4 6.2
9750 3.2 37.8 250 16 8 9.8 5.4 | 4.8 40.6 250 18 9 9.9 5.4
9500 3.8 38.8 250 16 8 7.9 4.4 | 5.4 41.7 255 18 9 8.7 4.8
9250 4.4 39.9 250 15 8 8.2 4.5 | 6.1 43.0 255 18 9 9.0 4.9
9000 5.1 41.2 250 15 8 9.7 5.3 | 6.8 44.2 255 18 9 9.6 5.2
8750 5.8 42.4 245 15 7 10.1 5.6 | 7.5 45.5 250 17 9 9.4 5.1
8500 6.5 43.7 245 14 7 8.8 4.8 | 8.2 46.8 255 17 9 8.8 4.8
8250 7.2 45.0 245 14 7 9.5 5.2 | 9.5 49.1 255 16 8 9.0 5.0
8000 8.4 47.1 250 12 6 8.3 4.5 | 10.2 50.4 250 15 8 8.9 4.9
7750 9.1 48.4 245 12 6 9.6 5.3 | 10.8 51.4 250 15 8 8.4 4.6
7500 9.8 49.6 240 12 6 9.3 5.1 | 11.4 52.5 250 14 7 9.0 4.9
7250 10.4 50.7 235 11 6 6.0 3.3 | 12.1 53.8 250 13 7 7.3 4.0
7000 10.8 51.4 245 10 5 7.1 3.9 | 12.6 54.7 250 14 7 7.9 4.3
6750 11.5 52.7 235 10 5 11.0 6.1 | 13.3 55.9 250 13 7 9.9 5.4
6500 12.2 54.0 225 10 5 8.6 4.7 | 14.0 57.2 245 12 6 9.6 5.3
6250 12.7 54.9 230 9 5 6.7 3.7 | 14.7 58.5 245 12 6 11.1 6.1
6000 13.1 55.6 235 7 4 5.0 2.7 | 15.6 60.1 250 12 6 13.6 7.5
5750 13.5 56.3 225 8 4 10.2 5.6 | 16.7 62.1 250 11 6 16.0 8.8
5500 15.5 59.9 245 6 3 54.4 29.8 | 17.9 64.2 250 10 5 12.2 6.7
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
- Kansas City/Pleasant Hill, MO Weather Forecast Office
- 1803 North 7 Highway
- Pleasant Hill, MO 64080-9421
- 816-540-6132 (6021 automated weather)
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- Page last modified: Sep 19th, 2023 19:10 UTC