Soaring Guidance
Issued by NWS Denver/Boulder, CO
Issued by NWS Denver/Boulder, CO
980
UXUS97 KBOU 300119
SRGBOU
Soaring Forecast
National Weather Service Denver/Boulder, Colorado
1919 MDT Saturday, June 29, 2024
This forecast is for Sunday, June 30, 2024:
If the trigger temperature of 78.4 F/25.8 C is reached...then
Thermal Soaring Index....................... Excellent
Maximum rate of lift........................ 1138 ft/min (5.8 m/s)
Maximum height of thermals.................. 16889 ft MSL (11573 ft AGL)
Forecast maximum temperature................... 94.0 F/34.9 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................. 13250 ft MSL (7933 ft AGL)
Thermal soaring outlook for Monday 07/01....... Fair
Wave Soaring Index............................. Poor
Wave Soaring Index trend (to 1800 MDT)......... No change
Height of stable layer (12-18K ft MSL)......... None
Weak PVA/NVA (through 1800 MDT)................ Weak PVA
Potential height of wave....................... 15900 ft MSL (10584 ft AGL)
Wave soaring outlook for Monday 07/01.......... Fair
Remarks...
Sunrise/Sunset.................... 05:35:06 / 20:31:34 MDT
Total possible sunshine........... 14 hr 56 min 28 sec (896 min 28 sec)
Altitude of sun at 13:03:20 MDT... 73.32 degrees
Upper air data from numerical model forecast valid on 06/30/2024 at 0600 MDT
Freezing level.................. 16597 ft MSL (11281 ft AGL)
Convective condensation level... 13062 ft MSL (7746 ft AGL)
Lifted condensation level....... 14548 ft MSL (9232 ft AGL)
Lifted index.................... -3.6
K index......................... +26.7
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 -65.8 -86.4 265 38 19 2.7 1.5 M M M M M
45000 -59.2 -74.6 240 49 25 6.4 3.5 M M M M M
40000 -48.8 -55.8 215 62 32 8.6 4.7 M M M M M
38000 -43.7 -46.7 220 57 29 8.6 4.7 M M M M M
36000 -38.6 -37.5 220 52 27 7.5 4.1 M M M M M
34000 -34.1 -29.4 225 48 25 7.4 4.0 M M M M M
32000 -29.2 -20.6 235 43 22 8.2 4.5 53.9 129.1 14.5 M M
30000 -24.9 -12.8 240 41 21 7.2 4.0 51.8 125.2 13.1 M M
29000 -22.7 -8.9 245 40 21 7.3 4.0 50.9 123.6 12.6 M M
28000 -20.5 -4.9 250 38 20 7.8 4.3 50.0 122.1 12.0 M M
27000 -18.1 -0.6 250 36 18 7.8 4.3 49.2 120.6 11.5 M M
26000 -15.8 3.6 250 33 17 7.8 4.3 48.5 119.3 11.1 M M
25000 -13.5 7.7 250 30 16 6.1 3.4 47.8 118.0 10.7 M M
24000 -11.9 10.6 250 28 14 5.5 3.0 46.1 115.0 9.4 M M
23000 -10.2 13.6 250 26 13 5.5 3.0 44.6 112.3 8.2 M M
22000 -8.6 16.5 250 23 12 5.1 2.8 43.2 109.7 7.1 M M
21000 -7.2 19.0 255 19 10 4.9 2.7 41.3 106.4 5.6 M M
20000 -5.8 21.6 260 14 7 5.0 2.7 39.7 103.4 4.1 M M
19500 -5.1 22.8 270 12 6 5.1 2.8 38.9 102.0 3.4 M M
19000 -4.3 24.3 275 10 5 5.9 3.3 38.2 100.7 2.8 M M
18500 -3.4 25.9 280 8 4 5.9 3.2 37.5 99.5 2.2 M M
18000 -2.6 27.3 290 6 3 5.9 3.2 36.8 98.3 1.7 M M
17500 -1.4 29.5 300 5 3 6.0 3.3 35.8 96.5 0.6 M M
17000 -0.5 31.1 315 4 2 6.6 3.6 35.2 95.4 -0.0 937 4.8
16500 0.4 32.7 320 5 3 6.8 3.7 34.7 94.5 -0.5 894 4.5
16000 1.3 34.3 320 6 3 7.1 3.9 34.2 93.6 -1.1 851 4.3
15500 2.4 36.3 320 6 3 7.9 4.4 33.9 93.0 -1.5 804 4.1
15000 3.5 38.3 320 6 3 7.9 4.3 33.6 92.4 -1.8 756 3.8
14500 4.6 40.3 320 6 3 8.0 4.4 33.3 91.9 -2.2 708 3.6
14000 5.8 42.4 315 6 3 8.1 4.4 33.0 91.4 -2.5 659 3.3
13500 6.9 44.4 310 5 3 7.5 4.1 32.7 90.8 -2.8 610 3.1
13000 8.0 46.4 300 4 2 7.4 4.1 32.3 90.1 -3.3 564 2.9
12500 9.0 48.2 290 3 2 6.8 3.7 31.9 89.4 -3.7 517 2.6
12000 9.9 49.8 265 3 1 6.5 3.5 31.4 88.5 -4.2 475 2.4
11500 10.8 51.4 235 3 1 6.0 3.3 30.9 87.5 -4.8 433 2.2
11000 11.6 52.9 225 4 2 5.4 3.0 30.2 86.3 -5.5 395 2.0
10500 12.4 54.3 220 6 3 3.5 1.9 29.5 85.1 -6.2 356 1.8
10250 12.6 54.7 220 6 3 2.8 1.6 28.9 84.1 -6.8 344 1.7
10000 12.9 55.2 215 7 4 5.3 2.9 28.5 83.3 -7.2 327 1.7
9750 13.3 55.9 210 8 4 5.6 3.1 28.2 82.7 -7.6 308 1.6
9500 13.7 56.7 205 9 5 4.2 2.3 27.8 82.1 -7.9 289 1.5
9250 13.9 57.0 205 10 5 2.6 1.4 27.3 81.1 -8.5 276 1.4
9000 14.0 57.2 200 12 6 3.7 2.0 26.8 80.2 -9.0 263 1.3
8750 14.3 57.7 200 13 7 4.2 2.3 26.3 79.4 -9.6 249 1.3
8500 14.5 58.1 195 15 8 4.3 2.4 25.9 78.6 -10.1 234 1.2
8250 14.8 58.6 195 17 9 4.7 2.6 25.5 77.9 -10.5 218 1.1
8000 15.1 59.2 190 19 10 4.3 2.3 25.1 77.2 -11.0 202 1.0
7750 15.3 59.5 190 22 11 3.4 1.8 24.6 76.4 -11.5 188 1.0
7500 15.5 59.9 190 23 12 2.9 1.6 24.1 75.4 -12.1 174 0.9
7250 15.7 60.3 185 25 13 2.6 1.4 23.6 74.5 -12.6 161 0.8
7000 15.9 60.6 180 26 13 3.7 2.0 23.1 73.5 -13.2 148 0.8
6750 16.2 61.2 175 28 15 2.8 1.5 22.6 72.7 -13.7 133 0.7
6500 16.2 61.2 175 27 14 0.3 0.2 22.0 71.6 -14.4 124 0.6
6250 16.2 61.2 170 24 13 -0.5 -0.3 21.2 70.2 -15.2 117 0.6
6000 16.2 61.2 165 22 11 2.0 1.1 20.5 68.9 -16.0 110 0.6
5750 16.5 61.7 160 19 10 6.8 3.7 20.1 68.2 -16.4 92 0.5
5500 17.1 62.8 155 14 7 7.4 4.1 20.0 67.9 -16.6 69 0.3
* * * * * * Numerical weather prediction model forecast data valid * * * * * *
06/30/2024 at 0900 MDT | 06/30/2024 at 1200 MDT
|
CAPE... +214.3 LI... -3.2 | CAPE... +586.0 LI... -3.5
CINH... -119.6 K Index... +24.8 | CINH... -58.2 K Index... +25.5
|
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 -64.8 -84.6 260 30 16 2.1 1.2 | -64.7 -84.5 250 30 16 2.6 1.4
45000 -59.1 -74.4 240 41 21 6.1 3.4 | -58.3 -72.9 245 40 21 6.6 3.6
40000 -49.0 -56.2 215 53 27 8.8 4.8 | -48.0 -54.4 235 45 23 7.8 4.3
38000 -43.7 -46.7 225 52 27 8.8 4.8 | -43.4 -46.1 235 49 25 7.8 4.3
36000 -38.5 -37.3 230 51 26 7.7 4.2 | -38.1 -36.6 240 52 27 7.5 4.1
34000 -33.5 -28.3 240 52 27 7.4 4.0 | -33.6 -28.5 245 55 28 7.5 4.1
32000 -29.1 -20.4 245 52 27 7.9 4.3 | -29.2 -20.6 245 57 30 7.1 3.9
30000 -24.8 -12.6 250 47 24 7.2 4.0 | -25.3 -13.5 250 48 25 6.5 3.6
29000 -22.7 -8.9 255 45 23 7.2 4.0 | -23.3 -9.9 250 43 22 6.6 3.6
28000 -20.6 -5.1 255 42 22 6.9 3.8 | -21.3 -6.3 250 39 20 6.9 3.8
27000 -18.5 -1.3 260 38 19 6.9 3.8 | -19.2 -2.6 250 36 19 6.9 3.8
26000 -16.4 2.5 260 33 17 6.9 3.8 | -17.1 1.2 250 33 17 6.9 3.8
25000 -14.4 6.1 260 29 15 6.5 3.6 | -15.0 5.0 250 30 15 7.3 4.0
24000 -12.4 9.7 260 28 14 6.3 3.5 | -12.8 9.0 250 29 15 7.4 4.1
23000 -10.5 13.1 260 26 13 6.3 3.5 | -10.6 12.9 255 28 15 7.4 4.1
22000 -8.7 16.3 260 24 12 4.4 2.4 | -8.4 16.9 255 27 14 4.8 2.7
21000 -7.7 18.1 260 20 10 3.7 2.0 | -7.3 18.9 260 26 14 4.1 2.2
20000 -6.8 19.8 265 16 8 4.2 2.3 | -6.1 21.0 260 25 13 4.5 2.5
19500 -6.3 20.7 265 14 7 4.9 2.7 | -5.6 21.9 265 25 13 5.1 2.8
19000 -5.2 22.6 270 13 7 8.9 4.9 | -4.8 23.4 265 24 12 6.4 3.5
18500 -3.8 25.2 270 12 6 8.7 4.8 | -3.9 25.0 265 22 11 6.4 3.5
18000 -2.5 27.5 270 11 5 6.5 3.5 | -2.9 26.8 265 21 11 7.7 4.2
17500 -1.7 28.9 275 9 5 5.4 2.9 | -1.0 30.2 265 18 9 8.3 4.6
17000 -0.5 31.1 285 7 4 6.5 3.5 | 0.2 32.4 270 17 9 6.7 3.7
16500 0.4 32.7 290 7 4 7.0 3.8 | 1.1 34.0 275 15 8 6.2 3.4
16000 1.4 34.5 300 8 4 7.2 3.9 | 1.9 35.4 275 14 7 6.2 3.4
15500 2.4 36.3 305 8 4 7.6 4.2 | 2.7 36.9 280 13 7 6.0 3.3
15000 3.5 38.3 310 9 4 7.5 4.1 | 3.5 38.3 285 12 6 5.9 3.3
14500 4.6 40.3 315 9 5 8.7 4.7 | 4.5 40.1 295 11 6 8.8 4.8
14000 5.9 42.6 320 9 5 8.6 4.7 | 5.7 42.3 300 11 5 8.5 4.7
13500 7.1 44.8 325 10 5 8.2 4.5 | 7.0 44.6 310 10 5 9.1 5.0
13000 8.2 46.8 325 9 5 8.2 4.5 | 8.3 46.9 315 10 5 9.1 5.0
12500 9.4 48.9 325 9 5 7.4 4.1 | 9.6 49.3 320 10 5 8.7 4.8
12000 10.4 50.7 330 8 4 7.0 3.9 | 10.9 51.6 325 10 5 8.5 4.7
11500 11.3 52.3 330 7 4 6.3 3.5 | 12.1 53.8 325 11 5 7.5 4.1
11000 12.1 53.8 330 6 3 5.6 3.1 | 13.1 55.6 325 10 5 6.6 3.6
10500 12.9 55.2 330 5 3 2.7 1.5 | 14.0 57.2 325 10 5 2.9 1.6
10250 13.0 55.4 330 5 3 2.0 1.1 | 14.1 57.4 320 10 5 3.1 1.7
10000 13.3 55.9 325 4 2 6.0 3.3 | 14.6 58.3 325 9 4 7.6 4.2
9750 13.8 56.8 325 4 2 6.0 3.3 | 15.0 59.0 325 8 4 7.0 3.8
9500 14.2 57.6 320 3 2 4.2 2.3 | 15.4 59.7 325 7 3 4.1 2.2
9250 14.4 57.9 310 3 1 2.3 1.3 | 15.5 59.9 330 5 3 1.3 0.7
9000 14.6 58.3 295 3 1 4.2 2.3 | 15.7 60.3 340 4 2 3.1 1.7
8750 14.9 58.8 280 3 1 5.3 2.9 | 15.8 60.4 015 2 1 3.7 2.0
8500 15.2 59.4 265 3 2 4.0 2.2 | 16.1 61.0 065 2 1 5.7 3.1
8250 15.5 59.9 245 5 2 3.4 1.8 | 16.5 61.7 070 2 1 6.8 3.7
8000 15.7 60.3 235 6 3 3.9 2.1 | 16.9 62.4 075 3 1 7.6 4.2
7750 15.9 60.6 230 7 4 4.2 2.3 | 17.5 63.5 075 3 1 9.6 5.3
7500 16.2 61.2 215 8 4 3.7 2.0 | 18.2 64.8 075 3 1 10.2 5.6
7250 16.4 61.5 200 8 4 3.9 2.1 | 19.0 66.2 075 3 1 10.3 5.7
7000 16.6 61.9 190 9 4 2.7 1.5 | 19.7 67.5 075 3 1 10.4 5.7
6750 16.6 61.9 170 10 5 6.0 3.3 | 20.5 68.9 070 3 2 10.5 5.8
6500 17.3 63.1 165 9 5 10.4 5.7 | 21.3 70.3 070 3 1 10.6 5.8
6250 18.0 64.4 160 9 5 9.5 5.2 | 22.1 71.8 070 3 1 10.4 5.7
6000 18.8 65.8 155 9 5 10.8 5.9 | 22.9 73.2 070 3 1 11.0 6.0
5750 19.7 67.5 155 9 4 16.0 8.8 | 23.9 75.0 070 3 1 18.7 10.3
5500 21.1 70.0 155 8 4 21.2 11.7 | 25.7 78.3 070 3 2 29.7 16.3
06/30/2024 at 1500 MDT | 06/30/2024 at 1800 MDT
|
CAPE... +1028.1 LI... -3.6 | CAPE... +1163.7 LI... -4.5
CINH... -9.7 K Index... +30.0 | CINH... -10.6 K Index... +35.7
|
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 -64.5 -84.1 235 33 17 2.8 1.5 | -65.0 -85.0 235 38 19 2.1 1.1
45000 -58.3 -72.9 240 45 23 6.1 3.3 | -59.0 -74.2 235 48 25 6.7 3.7
40000 -47.9 -54.2 240 53 27 8.5 4.6 | -48.4 -55.1 235 54 28 8.3 4.5
38000 -42.8 -45.0 235 55 28 8.5 4.6 | -43.4 -46.1 235 56 29 8.3 4.5
36000 -37.8 -36.0 235 56 29 7.2 3.9 | -38.5 -37.3 235 58 30 7.5 4.1
34000 -33.4 -28.1 240 56 29 7.3 4.0 | -33.5 -28.3 235 58 30 7.4 4.0
32000 -29.0 -20.2 245 57 29 6.7 3.7 | -29.1 -20.4 240 59 30 7.5 4.1
30000 -25.6 -14.1 250 54 28 5.8 3.2 | -24.9 -12.8 240 54 28 7.1 3.9
29000 -23.9 -11.0 250 53 27 5.8 3.2 | -22.8 -9.0 240 52 27 7.2 3.9
28000 -22.1 -7.8 250 51 26 7.6 4.2 | -20.8 -5.4 245 50 26 6.5 3.5
27000 -19.3 -2.7 250 46 24 7.5 4.1 | -18.9 -2.0 250 49 25 6.5 3.6
26000 -17.2 1.0 250 43 22 7.6 4.2 | -17.0 1.4 250 49 25 6.5 3.6
25000 -15.0 5.0 250 40 20 7.3 4.0 | -15.1 4.8 255 48 25 6.8 3.7
24000 -12.8 9.0 255 39 20 7.3 4.0 | -13.1 8.4 255 44 23 6.9 3.8
23000 -10.5 13.1 255 39 20 7.3 4.0 | -11.1 12.0 255 41 21 6.9 3.8
22000 -8.4 16.9 260 38 20 6.0 3.3 | -9.1 15.6 255 37 19 6.1 3.3
21000 -6.7 19.9 260 36 18 6.1 3.3 | -7.4 18.7 255 31 16 5.9 3.2
20000 -5.1 22.8 265 33 17 6.2 3.4 | -5.8 21.6 255 25 13 5.9 3.2
19500 -4.2 24.4 265 32 17 5.7 3.1 | -4.9 23.2 255 22 11 6.0 3.3
19000 -3.6 25.5 265 31 16 4.7 2.6 | -4.1 24.6 250 20 10 6.4 3.5
18500 -3.0 26.6 265 29 15 4.7 2.6 | -3.1 26.4 250 18 9 6.4 3.5
18000 -2.2 28.0 270 27 14 6.3 3.4 | -2.2 28.0 250 17 9 6.4 3.5
17500 -1.3 29.7 270 25 13 6.4 3.5 | -0.8 30.6 245 17 9 6.4 3.5
17000 -0.4 31.3 275 24 12 6.4 3.5 | 0.1 32.2 245 16 8 6.7 3.7
16500 0.5 32.9 275 22 11 6.3 3.5 | 1.1 34.0 245 16 8 6.9 3.8
16000 1.5 34.7 275 20 10 6.2 3.4 | 2.1 35.8 245 16 8 7.2 3.9
15500 2.4 36.3 280 18 9 7.1 3.9 | 3.2 37.8 240 16 8 8.1 4.5
15000 3.4 38.1 280 16 8 7.1 3.9 | 4.4 39.9 240 16 8 8.2 4.5
14500 4.5 40.1 280 15 8 7.9 4.3 | 5.5 41.9 235 15 8 7.4 4.1
14000 6.3 43.3 285 12 6 8.3 4.6 | 6.6 43.9 235 14 7 7.5 4.1
13500 7.5 45.5 285 10 5 7.8 4.3 | 7.7 45.9 230 13 7 7.8 4.3
13000 8.6 47.5 290 9 4 7.8 4.3 | 8.8 47.8 225 12 6 7.9 4.3
12500 9.8 49.6 290 7 4 8.6 4.7 | 10.0 50.0 220 11 5 7.9 4.4
12000 11.1 52.0 300 6 3 8.8 4.8 | 11.2 52.2 210 9 5 8.0 4.4
11500 12.4 54.3 305 5 3 8.1 4.4 | 12.3 54.1 190 8 4 8.0 4.4
11000 13.5 56.3 310 4 2 7.7 4.2 | 13.4 56.1 185 7 4 8.0 4.4
10500 14.5 58.1 310 3 2 3.2 1.8 | 14.5 58.1 175 7 3 4.8 2.6
10250 14.6 58.3 310 3 1 4.6 2.5 | 14.8 58.6 175 7 3 6.6 3.6
10000 15.1 59.2 000 0 0 9.4 5.2 | 15.5 59.9 175 7 3 12.3 6.7
9750 15.6 60.1 125 2 1 8.4 4.6 | 16.3 61.3 175 7 3 11.2 6.1
9500 16.1 61.0 125 4 2 7.7 4.2 | 17.1 62.8 175 7 3 10.1 5.5
9250 16.6 61.9 125 4 2 7.8 4.3 | 17.8 64.0 175 6 3 9.1 5.0
9000 17.2 63.0 125 4 2 10.1 5.6 | 18.5 65.3 175 6 3 10.6 5.8
8750 18.0 64.4 125 4 2 10.7 5.8 | 19.3 66.7 170 6 3 10.9 6.0
8500 18.7 65.7 125 4 2 10.1 5.5 | 20.1 68.2 170 6 3 10.0 5.5
8250 19.4 66.9 120 4 2 9.6 5.2 | 20.8 69.4 170 6 3 9.3 5.1
8000 20.1 68.2 120 4 2 10.6 5.8 | 21.5 70.7 170 6 3 9.7 5.3
7750 21.0 69.8 120 4 2 11.2 6.2 | 22.3 72.1 170 6 3 9.8 5.4
7500 21.8 71.2 120 4 2 10.1 5.5 | 23.0 73.4 170 6 3 10.1 5.5
7250 22.5 72.5 120 4 2 9.9 5.5 | 23.7 74.7 170 6 3 10.3 5.7
7000 23.2 73.8 120 4 2 9.5 5.2 | 24.5 76.1 170 6 3 10.1 5.5
6750 23.9 75.0 120 4 2 9.7 5.3 | 25.2 77.4 170 6 3 9.9 5.4
6500 24.7 76.5 120 4 2 10.5 5.8 | 26.0 78.8 170 6 3 10.0 5.5
6250 25.5 77.9 115 4 2 10.5 5.8 | 26.7 80.1 170 5 3 10.5 5.8
6000 26.3 79.3 115 4 2 10.7 5.9 | 27.5 81.5 170 5 3 8.8 4.8
5750 27.3 81.1 115 4 2 18.5 10.1 | 28.2 82.8 170 5 3 10.6 5.8
5500 29.1 84.4 115 4 2 30.3 16.6 | 29.2 84.6 165 5 3 18.7 10.3
________________________________________________________________________________
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 near the old Stapleton
Airport site in Denver, Colorado at
North Latitude: 39 deg 46 min 5.016 sec
West Longitude: 104 deg 52 min 9.984 sec
Elevation: 5285 feet (1611 meters)
and may not be representative of other areas along the Front Range of the
Colorado Rocky Mountains. 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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