- Warnings
- Observations
- Forecasts
- Text Messages
- Forecast Models
- Climate
- Weather Safety
- Education/Outreach
- Information Center
- Contact Us
RSS Feeds
Soaring Guidance
Issued by NWS Denver/Boulder, CO
Issued by NWS Denver/Boulder, CO
000
UXUS97 KBOU 131211
SRGBOU
Soaring Forecast
National Weather Service Denver/Boulder, Colorado
0611 MDT Saturday, April 13, 2024
This forecast is for Saturday, April 13, 2024:
If the trigger temperature of 66.7 F/19.3 C is reached...then
Thermal Soaring Index....................... Excellent
Maximum rate of lift........................ 1414 ft/min (7.2 m/s)
Maximum height of thermals.................. 20515 ft MSL (15222 ft AGL)
Forecast maximum temperature................... 80.0 F/27.1 C
Time of trigger temperature.................... 0945 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................. 16568 ft MSL (11276 ft AGL)
Thermal soaring outlook for Sunday 04/14....... Excellent
Wave Soaring Index............................. Poor
Wave Soaring Index trend (to 1800 MDT).........
Height of stable layer (12-18K ft MSL)......... None
Weak PVA/NVA (through 1800 MDT)................ Weak NVA
Potential height of wave....................... 16097 ft MSL (10804 ft AGL)
Wave soaring outlook for Sunday 04/14.......... Fair
Remarks...
Sunrise/Sunset.................... 06:23:34 / 19:36:02 MDT
Total possible sunshine........... 13 hr 12 min 29 sec (792 min 29 sec)
Altitude of sun at 12:59:48 MDT... 59.67 degrees
Upper air data from numerical model forecast valid on 04/13/2024 at 0600 MDT
Freezing level.................. 12334 ft MSL (7041 ft AGL)
Convective condensation level... 14408 ft MSL (9115 ft AGL)
Lifted condensation level....... 16506 ft MSL (11214 ft AGL)
Lifted index.................... -4.6
K index......................... +22.8
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 -56.6 -69.9 260 45 23 0.2 0.1 M M M M M
45000 -56.3 -69.3 260 52 27 -0.6 -0.3 M M M M M
40000 -57.5 -71.5 255 43 22 -0.7 -0.4 M M M M M
38000 -56.3 -69.3 250 42 21 3.4 1.9 M M M M M
36000 -54.3 -65.7 245 41 21 3.4 1.9 M M M M M
34000 -51.9 -61.4 235 38 20 5.5 3.0 M M M M M
32000 -48.6 -55.5 225 30 15 5.5 3.0 M M M M M
30000 -44.6 -48.3 215 23 12 9.3 5.1 30.6 87.0 2.9 M M
29000 -41.8 -43.2 220 21 11 9.3 5.1 30.3 86.6 2.8 M M
28000 -38.3 -36.9 220 17 9 9.3 5.1 30.2 86.4 2.7 M M
27000 -35.6 -32.1 225 16 8 8.9 4.9 30.0 86.0 2.6 M M
26000 -32.9 -27.2 225 16 8 8.9 4.9 29.6 85.3 2.3 M M
25000 -30.3 -22.5 225 16 8 8.9 4.9 29.3 84.8 2.1 M M
24000 -27.7 -17.9 225 16 8 8.2 4.5 29.1 84.3 1.9 M M
23000 -25.2 -13.4 225 17 9 8.2 4.5 28.4 83.1 1.3 M M
22000 -22.8 -9.0 225 17 9 8.2 4.5 27.9 82.2 0.9 M M
21000 -20.4 -4.7 220 16 8 7.6 4.2 27.3 81.1 0.4 M M
20000 -18.2 -0.8 215 13 7 7.7 4.2 26.5 79.7 -0.3 1365 6.9
19500 -17.0 1.4 210 12 6 7.7 4.2 26.1 79.0 -0.7 1317 6.7
19000 -15.9 3.4 205 11 5 7.8 4.3 25.8 78.5 -1.0 1268 6.4
18500 -14.8 5.4 195 9 5 6.8 3.7 25.4 77.7 -1.3 1221 6.2
18000 -13.8 7.2 180 9 4 6.9 3.8 24.9 76.8 -1.8 1177 6.0
17500 -12.8 9.0 165 9 4 7.3 4.0 24.4 76.0 -2.3 1132 5.7
17000 -11.7 10.9 150 9 5 7.7 4.2 24.1 75.3 -2.6 1083 5.5
16500 -10.6 12.9 140 9 5 7.7 4.2 23.7 74.7 -3.0 1035 5.3
16000 -9.5 14.9 130 10 5 7.5 4.1 23.4 74.1 -3.4 987 5.0
15500 -8.4 16.9 125 11 5 7.6 4.2 23.0 73.4 -3.7 939 4.8
15000 -7.3 18.9 120 11 6 7.6 4.2 22.6 72.7 -4.1 892 4.5
14500 -5.6 21.9 120 10 5 7.6 4.1 22.1 71.8 -4.7 820 4.2
14000 -4.4 24.1 120 10 5 9.2 5.0 21.9 71.4 -4.9 768 3.9
13500 -3.0 26.6 120 9 5 9.0 4.9 21.8 71.2 -5.1 713 3.6
13000 -1.7 28.9 120 8 4 9.5 5.2 21.7 71.0 -5.2 657 3.3
12500 -0.2 31.6 130 6 3 9.5 5.2 21.6 71.0 -5.2 599 3.0
12000 1.2 34.2 140 5 2 9.0 4.9 21.6 70.8 -5.3 542 2.8
11500 2.5 36.5 165 3 2 9.0 5.0 21.4 70.6 -5.4 487 2.5
11000 3.8 38.8 200 3 2 7.9 4.3 21.3 70.3 -5.6 434 2.2
10500 4.9 40.8 245 4 2 8.3 4.6 20.9 69.7 -6.0 385 2.0
10250 5.5 41.9 260 5 3 5.3 2.9 20.8 69.4 -6.2 361 1.8
10000 5.8 42.4 265 6 3 5.4 3.0 20.3 68.6 -6.6 344 1.7
9750 6.4 43.5 275 8 4 8.3 4.5 20.2 68.3 -6.8 320 1.6
9500 6.9 44.4 285 10 5 7.9 4.4 20.0 68.0 -7.0 296 1.5
9250 7.5 45.5 290 12 6 6.5 3.5 19.9 67.7 -7.2 272 1.4
9000 7.9 46.2 290 14 7 6.2 3.4 19.5 67.2 -7.5 252 1.3
8750 8.4 47.1 290 16 8 7.7 4.2 19.3 66.8 -7.7 229 1.2
8500 8.9 48.0 290 18 9 7.4 4.1 19.2 66.5 -7.9 206 1.0
8250 9.5 49.1 290 20 10 7.3 4.0 19.0 66.2 -8.2 182 0.9
8000 10.0 50.0 290 22 11 7.6 4.2 18.8 65.9 -8.4 159 0.8
7750 10.6 51.1 290 23 12 8.7 4.8 18.7 65.6 -8.5 133 0.7
7500 11.3 52.3 290 25 13 8.8 4.8 18.6 65.5 -8.6 107 0.5
7250 11.9 53.4 290 26 14 7.9 4.3 18.5 65.3 -8.8 81 0.4
7000 12.4 54.3 290 28 14 7.1 3.9 18.3 65.0 -9.0 57 0.3
6750 12.9 55.2 290 30 15 7.3 4.0 18.1 64.7 -9.2 35 0.2
6500 13.3 55.9 290 32 16 2.4 1.3 17.8 64.1 -9.6 15 0.1
6250 13.2 55.8 285 30 15 -3.0 -1.6 17.0 62.6 -10.4 12 0.1
6000 13.0 55.4 280 28 14 -2.0 -1.1 16.1 60.9 -11.4 11 0.1
5750 12.8 55.0 275 25 13 -5.2 -2.9 15.1 59.3 -12.4 11 0.1
5500 12.1 53.8 270 19 10 -13.3 -7.3 13.7 56.7 -13.8 24 0.1
* * * * * * Numerical weather prediction model forecast data valid * * * * * *
04/13/2024 at 0900 MDT | 04/13/2024 at 1200 MDT
|
CAPE... +0.9 LI... 0.0 | CAPE... +176.8 LI... -1.5
CINH... -55.3 K Index... +24.7 | CINH... -14.9 K Index... +16.2
|
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 -56.6 -69.9 265 46 23 0.5 0.3 | -57.3 -71.1 260 43 22 0.3 0.2
45000 -55.9 -68.6 270 50 26 -0.7 -0.4 | -57.1 -70.8 265 51 26 -1.2 -0.7
40000 -57.3 -71.1 265 48 24 -0.9 -0.5 | -58.9 -74.0 265 55 28 -1.0 -0.6
38000 -55.7 -68.3 265 46 24 4.6 2.5 | -56.3 -69.3 265 53 27 6.5 3.5
36000 -52.9 -63.2 260 44 23 4.6 2.5 | -52.4 -62.3 265 49 25 6.5 3.5
34000 -49.9 -57.8 255 40 21 6.1 3.3 | -48.3 -54.9 265 48 25 7.7 4.2
32000 -46.2 -51.2 250 32 17 6.1 3.4 | -43.7 -46.7 270 52 27 7.7 4.2
30000 -42.6 -44.7 235 24 12 5.7 3.1 | -39.0 -38.2 275 51 26 5.7 3.1
29000 -40.5 -40.9 220 19 10 5.6 3.1 | -37.3 -35.1 275 46 24 5.7 3.1
28000 -38.8 -37.8 195 18 9 5.7 3.1 | -35.6 -32.1 275 41 21 5.7 3.1
27000 -36.8 -34.2 185 18 9 9.1 5.0 | -34.0 -29.2 275 35 18 5.0 2.7
26000 -34.2 -29.6 190 18 9 8.8 4.8 | -32.5 -26.5 275 26 14 5.1 2.8
25000 -31.6 -24.9 200 19 10 8.8 4.8 | -31.0 -23.8 275 17 9 5.1 2.8
24000 -28.9 -20.0 205 18 10 9.0 4.9 | -29.3 -20.7 280 10 5 8.2 4.5
23000 -26.2 -15.2 210 14 7 9.0 5.0 | -26.8 -16.2 290 8 4 8.4 4.6
22000 -23.5 -10.3 225 11 5 9.0 5.0 | -24.4 -11.9 305 7 4 8.4 4.6
21000 -21.0 -5.8 245 8 4 7.2 3.9 | -22.0 -7.6 320 8 4 7.2 4.0
20000 -18.9 -2.0 255 6 3 7.4 4.0 | -19.8 -3.6 320 11 6 7.3 4.0
19500 -17.8 -0.0 265 5 2 7.4 4.1 | -18.7 -1.7 320 13 7 7.3 4.0
19000 -16.8 1.8 275 4 2 7.5 4.1 | -17.6 0.3 320 15 8 7.2 4.0
18500 -15.7 3.7 295 3 2 7.0 3.8 | -16.5 2.3 320 17 9 8.2 4.5
18000 -14.7 5.5 320 3 1 7.0 3.9 | -15.2 4.6 320 18 9 8.2 4.5
17500 -13.7 7.3 350 3 1 7.6 4.1 | -14.0 6.8 320 18 9 8.6 4.7
17000 -12.5 9.5 010 3 1 8.1 4.5 | -12.7 9.1 320 19 10 8.9 4.9
16500 -11.3 11.7 025 3 2 8.2 4.5 | -11.3 11.7 320 19 10 9.0 4.9
16000 -10.1 13.8 030 3 2 7.7 4.2 | -10.0 14.0 320 18 10 8.8 4.8
15500 -9.0 15.8 035 3 2 7.7 4.2 | -8.7 16.3 320 18 9 8.8 4.8
15000 -7.8 18.0 040 3 2 8.4 4.6 | -6.8 19.8 320 16 8 8.6 4.7
14500 -5.9 21.4 040 3 2 8.5 4.7 | -5.5 22.1 325 15 8 8.6 4.7
14000 -4.6 23.7 030 3 2 8.9 4.9 | -4.3 24.3 325 13 7 8.6 4.7
13500 -3.3 26.1 020 4 2 8.8 4.8 | -3.0 26.6 325 12 6 8.6 4.7
13000 -1.9 28.6 360 4 2 9.6 5.3 | -1.7 28.9 325 11 6 8.9 4.9
12500 -0.5 31.1 345 5 2 9.6 5.3 | -0.4 31.3 325 10 5 8.9 4.9
12000 0.9 33.6 330 6 3 9.1 5.0 | 0.9 33.6 325 9 5 9.0 5.0
11500 2.3 36.1 325 7 4 9.1 5.0 | 2.2 36.0 330 9 5 9.0 5.0
11000 3.6 38.5 325 8 4 8.9 4.9 | 3.6 38.5 330 9 4 9.4 5.1
10500 4.9 40.8 320 9 5 9.6 5.3 | 5.0 41.0 330 9 5 10.4 5.7
10250 5.6 42.1 320 10 5 6.0 3.3 | 5.7 42.3 330 9 5 5.3 2.9
10000 6.0 42.8 320 10 5 7.0 3.9 | 5.9 42.6 330 9 5 6.6 3.6
9750 6.7 44.1 315 11 6 11.2 6.2 | 6.8 44.2 330 10 5 12.5 6.8
9500 7.5 45.5 315 12 6 10.8 5.9 | 7.6 45.7 330 10 5 11.6 6.4
9250 8.3 46.9 315 12 6 8.4 4.6 | 8.5 47.3 330 11 6 9.3 5.1
9000 8.8 47.8 315 13 7 7.8 4.3 | 9.0 48.2 325 11 6 8.4 4.6
8750 9.5 49.1 315 14 7 10.2 5.6 | 9.8 49.6 325 11 6 10.6 5.8
8500 10.3 50.5 315 15 8 9.5 5.2 | 10.5 50.9 325 11 6 10.0 5.5
8250 11.0 51.8 315 16 8 10.0 5.5 | 11.3 52.3 325 12 6 10.0 5.5
8000 11.8 53.2 315 17 9 9.9 5.4 | 12.0 53.6 325 11 6 9.6 5.3
7750 12.5 54.5 315 18 9 9.7 5.3 | 12.7 54.9 325 11 6 9.3 5.1
7500 13.2 55.8 315 19 10 9.0 4.9 | 13.4 56.1 325 11 6 9.3 5.1
7250 13.8 56.8 310 20 10 7.3 4.0 | 14.1 57.4 325 11 6 9.6 5.2
7000 14.3 57.7 310 22 11 6.2 3.4 | 14.8 58.6 320 11 6 9.7 5.3
6750 14.8 58.6 305 24 13 6.5 3.6 | 15.5 59.9 320 10 5 9.7 5.3
6500 15.1 59.2 300 26 14 1.1 0.6 | 16.2 61.2 320 10 5 10.3 5.7
6250 14.9 58.8 295 23 12 -3.5 -1.9 | 17.0 62.6 320 9 5 11.0 6.0
6000 14.6 58.3 290 19 10 -3.7 -2.0 | 17.8 64.0 320 9 5 10.4 5.7
5750 14.3 57.7 285 15 8 0.2 0.1 | 18.6 65.5 320 9 4 12.0 6.6
5500 14.7 58.5 275 11 6 13.5 7.4 | 19.7 67.5 320 8 4 18.1 9.9
04/13/2024 at 1500 MDT | 04/13/2024 at 1800 MDT
|
CAPE... +73.6 LI... -0.3 | CAPE... +56.1 LI... -0.7
CINH... -10.6 K Index... +15.5 | CINH... -8.3 K Index... +22.0
|
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 -58.0 -72.4 260 47 24 0.4 0.2 | -58.5 -73.3 260 50 26 0.7 0.4
45000 -57.6 -71.7 265 52 27 -0.5 -0.3 | -57.7 -71.9 260 53 27 -0.7 -0.4
40000 -58.3 -72.9 260 53 27 -0.3 -0.2 | -58.8 -73.8 255 50 26 -0.6 -0.3
38000 -55.9 -68.6 260 53 27 5.6 3.1 | -56.5 -69.7 260 47 24 5.5 3.0
36000 -52.5 -62.5 265 53 27 5.6 3.1 | -53.2 -63.8 265 42 22 5.5 3.0
34000 -48.8 -55.8 265 52 27 7.5 4.1 | -49.4 -56.9 270 39 20 7.6 4.1
32000 -44.3 -47.7 270 49 25 7.5 4.1 | -44.9 -48.8 270 39 20 7.6 4.1
30000 -39.1 -38.4 275 45 23 8.0 4.4 | -39.7 -39.5 275 38 20 8.0 4.4
29000 -36.7 -34.1 275 44 23 8.0 4.4 | -37.3 -35.1 275 38 20 8.0 4.4
28000 -34.3 -29.7 275 42 22 8.0 4.4 | -34.9 -30.8 280 38 20 8.0 4.4
27000 -32.2 -26.0 275 40 20 4.7 2.6 | -32.5 -26.5 280 38 19 7.5 4.1
26000 -30.8 -23.4 275 35 18 4.8 2.7 | -30.3 -22.5 280 37 19 7.5 4.1
25000 -29.3 -20.7 270 31 16 4.8 2.7 | -28.0 -18.4 280 36 19 7.5 4.1
24000 -27.8 -18.0 270 26 14 6.8 3.7 | -25.9 -14.6 275 35 18 5.1 2.8
23000 -25.8 -14.4 270 20 10 6.8 3.7 | -24.4 -11.9 275 32 17 5.3 2.9
22000 -23.8 -10.8 265 13 7 6.9 3.8 | -22.8 -9.0 270 29 15 5.4 3.0
21000 -21.6 -6.9 265 10 5 8.5 4.7 | -20.9 -5.6 270 26 13 7.7 4.2
20000 -19.0 -2.2 265 14 7 8.4 4.6 | -18.7 -1.7 265 23 12 7.7 4.2
19500 -17.8 -0.0 260 15 8 8.5 4.6 | -17.6 0.3 265 21 11 7.7 4.2
19000 -16.5 2.3 260 17 9 8.5 4.7 | -16.5 2.3 260 20 10 7.8 4.3
18500 -15.3 4.5 260 17 9 7.6 4.2 | -15.3 4.5 265 18 9 7.5 4.1
18000 -14.2 6.4 265 16 8 7.7 4.2 | -14.2 6.4 270 16 8 7.5 4.1
17500 -13.0 8.6 265 15 8 7.8 4.3 | -13.1 8.4 275 14 7 7.4 4.1
17000 -11.9 10.6 275 15 7 7.8 4.3 | -12.0 10.4 280 13 7 7.3 4.0
16500 -10.7 12.7 285 14 7 7.8 4.3 | -10.9 12.4 290 12 6 7.4 4.1
16000 -9.6 14.7 290 14 7 7.3 4.0 | -9.7 14.5 295 11 6 8.8 4.8
15500 -8.5 16.7 300 14 7 7.3 4.0 | -7.9 17.8 305 10 5 8.9 4.9
15000 -6.6 20.1 305 14 7 9.0 4.9 | -6.6 20.1 310 10 5 9.2 5.1
14500 -5.3 22.5 310 12 6 9.0 4.9 | -5.2 22.6 315 9 5 9.2 5.1
14000 -4.1 24.6 310 11 6 8.5 4.7 | -3.9 25.0 315 9 5 9.0 5.0
13500 -2.8 27.0 315 9 5 8.6 4.7 | -2.5 27.5 320 8 4 9.1 5.0
13000 -1.5 29.3 315 8 4 9.3 5.1 | -1.2 29.8 320 8 4 8.9 4.9
12500 -0.2 31.6 315 7 4 9.2 5.1 | 0.1 32.2 320 8 4 8.9 4.9
12000 1.2 34.2 315 7 3 9.7 5.3 | 1.5 34.7 320 7 4 9.1 5.0
11500 2.6 36.7 315 6 3 9.7 5.3 | 2.8 37.0 320 7 4 9.0 5.0
11000 4.1 39.4 315 6 3 9.9 5.4 | 4.2 39.6 315 7 3 9.5 5.2
10500 5.5 41.9 315 6 3 10.7 5.9 | 5.6 42.1 315 7 3 10.4 5.7
10250 6.3 43.3 315 6 3 6.6 3.6 | 6.3 43.3 315 7 3 5.9 3.2
10000 6.7 44.1 315 6 3 7.7 4.2 | 6.6 43.9 315 7 3 7.3 4.0
9750 7.5 45.5 315 6 3 12.3 6.8 | 7.5 45.5 310 7 4 12.5 6.9
9500 8.4 47.1 315 6 3 11.7 6.4 | 8.3 46.9 310 7 4 11.8 6.5
9250 9.2 48.6 315 6 3 9.5 5.2 | 9.2 48.6 310 7 4 9.6 5.2
9000 9.8 49.6 315 6 3 8.6 4.7 | 9.8 49.6 310 7 4 8.7 4.8
8750 10.6 51.1 315 6 3 10.8 5.9 | 10.6 51.1 310 7 4 10.8 5.9
8500 11.4 52.5 315 6 3 10.2 5.6 | 11.3 52.3 310 7 4 10.2 5.6
8250 12.1 53.8 315 6 3 10.7 5.9 | 12.1 53.8 310 7 4 10.0 5.5
8000 12.9 55.2 315 6 3 10.5 5.8 | 12.9 55.2 305 7 4 9.5 5.2
7750 13.7 56.7 315 6 3 9.9 5.4 | 13.6 56.5 305 8 4 9.2 5.0
7500 14.4 57.9 315 6 3 9.8 5.4 | 14.2 57.6 305 8 4 9.4 5.2
7250 15.2 59.4 315 6 3 9.8 5.4 | 15.0 59.0 305 8 4 10.3 5.7
7000 15.9 60.6 315 6 3 9.8 5.4 | 15.8 60.4 305 8 4 10.6 5.8
6750 16.6 61.9 315 6 3 9.4 5.2 | 16.5 61.7 305 8 4 9.6 5.3
6500 17.3 63.1 315 5 3 10.3 5.6 | 17.2 63.0 305 8 4 9.8 5.4
6250 18.2 64.8 315 5 3 11.6 6.3 | 18.0 64.4 305 8 4 10.5 5.8
6000 19.0 66.2 315 5 3 10.7 5.9 | 18.8 65.8 305 8 4 10.3 5.6
5750 19.8 67.6 315 5 3 12.6 6.9 | 19.5 67.1 305 8 4 10.2 5.6
5500 21.0 69.8 315 5 3 20.7 11.4 | 20.3 68.5 305 7 4 12.0 6.6
________________________________________________________________________________
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.
042613
- National Weather Service
- Binghamton, NY Weather Forecast Office
- 32 Dawes Drive
- Johnson City, NY 13790
- (607) 729-1597
- Page Author: BGM Webmaster
- Web Master's E-mail: bgm.webmaster@noaa.gov
- Page last modified: Sep 19th, 2023 19:10 UTC