Soaring Guidance
Issued by NWS Denver/Boulder, CO
Issued by NWS Denver/Boulder, CO
000
UXUS97 KBOU 151329
SRGBOU
Soaring Forecast
National Weather Service Denver/Boulder, Colorado
0729 MDT Saturday, June 15, 2013
This forecast is for Saturday, June 15, 2013:
If the trigger temperature of 71.5 F/21.9 C is reached...then
Thermal Soaring Index....................... Fair
Maximum rate of lift........................ 297 ft/min (1.5 m/s)
Maximum height of thermals.................. 10838 ft MSL (5553 ft AGL)
Forecast maximum temperature................... 82.0 F/28.2 C
Time of trigger temperature.................... 0830 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................. 10226 ft MSL (4941 ft AGL)
Thermal soaring outlook for Sunday 06/16....... Excellent
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....................... 15883 ft MSL (10598 ft AGL)
Wave soaring outlook for Sunday 06/16.......... Poor
Remarks... Scattered to broken low clouds moving into eastern portions of denver
between 8 and 9 am. Thunderstorms possible after 4 pm this afternoon.
Sunrise/Sunset.................... 05:31:01 / 20:28:58 MDT
Total possible sunshine........... 14 hr 57 min 56 sec (897 min 56 sec)
Altitude of sun at 13:00:08 MDT... 73.54 degrees
Upper air data from rawinsonde observation taken on 06/15/2013 at 0600 MDT
Freezing level.................. 15226 ft MSL (9941 ft AGL)
Convective condensation level... 15048 ft MSL (9763 ft AGL)
Lifted condensation level....... 14331 ft MSL (9046 ft AGL)
Lifted index.................... -5.0
K index......................... +16.8
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 -59.3 -74.7 220 28 14 -3.4 -1.9 95.5 203.9 39.3 M M
45000 -60.0 -76.0 245 61 32 1.7 1.0 69.9 157.9 26.2 M M
40000 -54.3 -65.7 240 53 27 6.3 3.5 55.9 132.5 18.7 M M
38000 -50.7 -59.3 230 48 25 6.0 3.3 52.4 126.3 16.8 M M
36000 -47.0 -52.6 240 46 24 6.0 3.3 49.2 120.6 15.0 M M
34000 -43.4 -46.1 245 47 24 6.2 3.4 46.1 115.0 13.2 M M
32000 -39.2 -38.6 245 45 23 6.2 3.4 42.8 109.1 11.1 M M
30000 -35.2 -31.4 255 43 22 9.2 5.0 40.4 104.7 9.6 M M
29000 -32.5 -26.5 255 41 21 9.5 5.2 40.2 104.3 9.5 M M
28000 -30.2 -22.4 255 39 20 6.4 3.5 39.2 102.5 8.9 M M
27000 -28.3 -18.9 250 37 19 6.4 3.5 37.9 100.3 8.0 M M
26000 -27.1 -16.8 250 35 18 7.7 4.2 35.9 96.5 6.4 M M
25000 -24.8 -12.6 255 33 17 7.9 4.3 35.1 95.2 5.9 M M
24000 -22.5 -8.5 265 31 16 8.6 4.7 34.2 93.5 5.2 M M
23000 -20.0 -4.0 270 31 16 8.4 4.6 33.7 92.6 4.9 M M
22000 -17.5 0.5 275 30 15 8.5 4.7 33.3 91.9 4.6 M M
21000 -15.4 4.3 265 24 12 6.3 3.5 32.3 90.1 3.8 M M
20000 -13.7 7.3 250 18 9 4.5 2.5 30.9 87.6 2.5 M M
19500 -12.7 9.1 245 16 8 9.6 5.3 30.5 86.9 2.1 M M
19000 -11.3 11.7 240 14 7 9.6 5.3 30.4 86.7 2.1 M M
18500 -9.8 14.4 245 14 7 9.7 5.3 30.4 86.7 2.0 M M
18000 -8.4 16.9 250 14 7 9.7 5.3 30.3 86.6 2.0 M M
17500 -6.9 19.6 255 14 7 9.7 5.3 30.3 86.5 2.0 M M
17000 -5.5 22.1 260 14 7 9.7 5.3 30.3 86.5 2.0 M M
16500 -4.0 24.8 265 14 7 9.7 5.3 30.3 86.6 2.0 M M
16000 -1.8 28.8 270 14 7 9.5 5.2 30.4 86.7 2.1 M M
15500 -0.5 31.1 260 13 7 9.4 5.2 30.3 86.5 2.0 M M
15000 0.9 33.6 250 13 7 9.5 5.2 30.2 86.4 1.9 M M
14500 2.3 36.1 240 13 7 9.5 5.2 30.2 86.4 1.8 M M
14000 3.7 38.7 235 13 7 9.5 5.2 30.2 86.4 1.8 M M
13500 5.0 41.0 240 12 6 9.6 5.3 30.2 86.3 1.7 M M
13000 6.5 43.7 240 12 6 9.5 5.2 30.1 86.2 1.7 M M
12500 8.0 46.4 255 11 6 9.9 5.4 30.1 86.2 1.8 M M
12000 9.3 48.7 270 11 6 6.6 3.6 29.9 85.8 1.6 M M
11500 10.4 50.7 285 11 6 7.3 4.0 29.4 84.9 1.2 M M
11000 11.1 52.0 295 11 6 -0.2 -0.1 28.6 83.5 0.5 M M
10500 10.5 50.9 290 10 5 -3.8 -2.1 26.9 80.5 -1.6 298 1.5
10250 9.7 49.5 300 10 5 -7.6 -4.2 25.6 78.0 -3.1 314 1.6
10000 9.4 48.9 335 11 6 1.3 0.7 24.5 76.1 -4.2 318 1.6
9750 9.7 49.5 340 12 6 6.0 3.3 24.1 75.4 -4.6 301 1.5
9500 10.0 50.0 350 14 7 1.9 1.0 23.7 74.7 -5.0 284 1.4
9250 10.0 50.0 350 15 8 -1.4 -0.8 22.9 73.3 -5.8 277 1.4
9000 10.0 50.0 355 17 9 2.9 1.6 22.2 71.9 -6.5 269 1.4
8750 10.5 50.9 355 18 9 8.7 4.8 21.9 71.4 -6.8 248 1.3
8500 11.1 52.0 360 18 9 9.6 5.3 21.9 71.4 -6.9 221 1.1
8250 11.8 53.2 360 19 10 9.1 5.0 21.8 71.3 -7.0 193 1.0
8000 12.5 54.5 360 19 10 10.3 5.6 21.8 71.3 -7.0 165 0.8
7750 13.2 55.8 005 17 9 6.1 3.4 21.8 71.2 -7.1 138 0.7
7500 13.3 55.9 005 14 7 1.1 0.6 21.2 70.2 -7.7 125 0.6
7250 13.5 56.3 010 12 6 3.7 2.0 20.7 69.2 -8.3 114 0.6
7000 13.6 56.5 020 10 5 -2.7 -1.5 20.1 68.2 -8.9 103 0.5
6750 13.1 55.6 015 10 5 -9.5 -5.2 18.7 65.7 -10.2 111 0.6
6500 12.7 54.9 005 11 6 2.0 1.1 17.6 63.7 -11.3 114 0.6
6250 13.3 55.9 360 11 6 9.4 5.1 17.5 63.4 -11.5 90 0.5
6000 13.8 56.8 355 12 6 7.2 3.9 17.3 63.2 -11.7 67 0.3
5750 14.4 57.9 355 10 5 8.7 4.8 17.2 62.9 -11.9 43 0.2
5500 14.9 58.8 355 7 4 4.9 2.7 17.0 62.7 -12.1 19 0.1
* * * * * * Numerical weather prediction model forecast data valid * * * * * *
06/15/2013 at 0900 MDT | 06/15/2013 at 1200 MDT
|
K index... +4.9 LI... +0.2 | K index... +9.9 LI... -3.6
CAPE... +55.4 CIN... -294.8 | CAPE... +634.9 CIN... -168.0
|
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 -60.3 -76.5 250 39 20 2.9 1.6 | -60.1 -76.2 250 39 20 3.4 1.8
45000 -56.5 -69.7 255 51 26 1.2 0.6 | -55.9 -68.6 250 48 25 0.8 0.4
40000 -54.7 -66.5 250 61 31 3.9 2.1 | -54.3 -65.7 250 62 32 6.3 3.4
38000 -51.4 -60.5 250 57 30 5.5 3.0 | -50.8 -59.4 250 59 31 5.9 3.2
36000 -48.2 -54.8 250 54 28 5.5 3.0 | -47.3 -53.1 250 56 29 5.9 3.2
34000 -44.0 -47.2 250 50 26 6.5 3.6 | -43.7 -46.7 250 52 27 6.1 3.3
32000 -40.1 -40.2 250 46 24 6.5 3.6 | -40.0 -40.0 250 48 25 6.1 3.3
30000 -35.7 -32.3 255 41 21 7.6 4.2 | -35.9 -32.6 255 43 22 7.5 4.1
29000 -33.4 -28.1 255 39 20 7.6 4.2 | -33.6 -28.5 255 42 21 7.5 4.1
28000 -31.2 -24.2 260 37 19 7.6 4.2 | -31.4 -24.5 255 40 20 7.5 4.1
27000 -29.1 -20.4 260 34 17 6.9 3.8 | -28.8 -19.8 255 37 19 6.6 3.6
26000 -27.0 -16.6 260 30 15 6.9 3.8 | -26.9 -16.4 255 35 18 6.6 3.6
25000 -24.9 -12.8 255 26 14 6.8 3.8 | -24.9 -12.8 255 32 17 6.4 3.5
24000 -22.5 -8.5 255 23 12 8.5 4.7 | -22.5 -8.5 255 29 15 8.8 4.8
23000 -19.9 -3.8 255 21 11 8.6 4.7 | -19.9 -3.8 250 26 13 8.8 4.8
22000 -17.4 0.7 260 19 10 8.7 4.8 | -17.2 1.0 245 23 12 8.8 4.8
21000 -15.1 4.8 265 19 10 7.2 3.9 | -15.2 4.6 250 23 12 6.6 3.6
20000 -13.0 8.6 270 20 10 7.2 4.0 | -13.2 8.2 255 25 13 6.8 3.7
19500 -11.9 10.6 270 21 11 7.3 4.0 | -12.3 9.9 260 25 13 6.8 3.7
19000 -10.8 12.6 275 22 11 7.5 4.1 | -11.2 11.8 260 26 13 8.3 4.5
18500 -9.7 14.5 275 23 12 7.7 4.2 | -10.0 14.0 260 25 13 8.6 4.7
18000 -8.6 16.5 275 24 13 7.8 4.3 | -8.7 16.3 260 23 12 8.7 4.8
17500 -7.3 18.9 275 25 13 9.5 5.2 | -7.4 18.7 260 23 12 9.5 5.2
17000 -5.9 21.4 275 25 13 9.3 5.1 | -6.0 21.2 260 22 12 9.4 5.2
16500 -3.8 25.2 275 25 13 9.6 5.2 | -4.5 23.9 260 22 11 9.6 5.3
16000 -2.4 27.7 275 24 13 9.5 5.2 | -3.1 26.4 265 21 11 9.7 5.3
15500 -0.9 30.4 275 24 12 9.7 5.3 | -1.6 29.1 265 21 11 9.5 5.2
15000 0.5 32.9 275 22 12 9.7 5.3 | -0.3 31.5 265 20 10 9.3 5.1
14500 2.0 35.6 275 21 11 9.6 5.2 | 1.1 34.0 265 19 10 9.2 5.1
14000 3.4 38.1 275 20 10 9.5 5.2 | 3.2 37.8 265 17 9 9.1 5.0
13500 4.8 40.6 275 19 10 9.3 5.1 | 4.6 40.3 265 16 8 9.1 5.0
13000 6.1 43.0 270 17 9 8.9 4.9 | 5.9 42.6 260 15 8 9.0 4.9
12500 7.5 45.5 270 15 8 8.6 4.7 | 7.2 45.0 260 14 7 8.5 4.7
12000 8.6 47.5 265 13 7 7.3 4.0 | 8.3 46.9 260 13 7 7.2 3.9
11500 9.7 49.5 265 12 6 7.0 3.8 | 9.4 48.9 260 11 6 6.5 3.6
11000 10.4 50.7 265 10 5 3.2 1.8 | 10.0 50.0 260 10 5 3.3 1.8
10500 10.8 51.4 275 9 5 3.2 1.8 | 10.5 50.9 270 8 4 2.5 1.4
10250 11.0 51.8 280 9 5 0.4 0.2 | 10.6 51.1 270 7 4 0.4 0.2
10000 10.9 51.6 290 8 4 -1.3 -0.7 | 10.6 51.1 280 6 3 0.4 0.2
9750 10.7 51.3 305 8 4 -0.9 -0.5 | 10.6 51.1 300 5 2 0.6 0.3
9500 10.6 51.1 320 9 5 -0.6 -0.3 | 10.6 51.1 330 5 2 0.9 0.5
9250 10.5 50.9 330 10 5 0.2 0.1 | 10.6 51.1 345 5 3 1.5 0.8
9000 10.5 50.9 340 10 5 1.3 0.7 | 10.6 51.1 360 6 3 3.0 1.6
8750 10.5 50.9 345 11 6 1.8 1.0 | 10.7 51.3 005 7 4 3.5 1.9
8500 10.6 51.1 350 12 6 2.3 1.2 | 10.8 51.4 015 9 4 5.7 3.1
8250 10.7 51.3 350 12 6 3.2 1.7 | 11.2 52.2 015 9 5 8.2 4.5
8000 10.8 51.4 350 13 7 3.1 1.7 | 11.8 53.2 015 10 5 8.9 4.9
7750 11.0 51.8 350 14 7 2.5 1.4 | 12.4 54.3 015 10 5 10.1 5.5
7500 11.1 52.0 350 14 7 2.8 1.5 | 13.1 55.6 015 10 5 10.0 5.5
7250 11.3 52.3 355 14 7 3.6 2.0 | 13.9 57.0 015 10 5 10.0 5.5
7000 11.5 52.7 355 14 7 2.5 1.4 | 14.6 58.3 010 10 5 9.7 5.3
6750 11.7 53.1 355 13 7 3.4 1.9 | 15.4 59.7 010 10 5 10.0 5.5
6500 12.1 53.8 355 12 6 8.8 4.8 | 16.2 61.2 010 10 5 11.2 6.1
6250 13.0 55.4 355 12 6 11.9 6.5 | 17.0 62.6 010 9 5 12.7 7.0
6000 13.8 56.8 355 12 6 9.2 5.0 | 17.9 64.2 010 9 5 9.0 4.9
5750 14.5 58.1 355 11 6 13.9 7.6 | 18.6 65.5 010 9 5 15.7 8.6
5500 16.0 60.8 355 11 5 27.0 14.8 | 20.6 69.1 010 9 5 37.2 20.4
06/15/2013 at 1500 MDT | 06/15/2013 at 1800 MDT
|
K index... +19.6 LI... -5.0 | K index... +25.9 LI... -4.0
CAPE... +1131.7 CIN... -84.7 | CAPE... +927.8 CIN... -1.6
|
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 -60.5 -76.9 245 42 22 2.7 1.5 | -60.6 -77.1 245 39 20 2.8 1.5
45000 -56.6 -69.9 250 53 27 2.0 1.1 | -56.7 -70.1 245 51 26 1.9 1.0
40000 -53.5 -64.3 255 66 34 4.0 2.2 | -53.8 -64.8 255 67 35 3.6 2.0
38000 -50.5 -58.9 255 65 34 5.0 2.7 | -51.2 -60.2 255 66 34 4.3 2.4
36000 -47.6 -53.7 255 64 33 4.9 2.7 | -48.6 -55.5 255 65 34 4.3 2.4
34000 -43.5 -46.3 255 60 31 6.5 3.6 | -44.4 -47.9 255 60 31 7.1 3.9
32000 -39.6 -39.3 255 54 28 6.5 3.6 | -40.1 -40.2 250 54 28 7.2 3.9
30000 -35.5 -31.9 255 48 25 7.0 3.9 | -35.4 -31.7 250 49 25 8.2 4.5
29000 -33.4 -28.1 255 46 24 7.0 3.9 | -33.0 -27.4 255 46 24 8.2 4.5
28000 -31.2 -24.2 260 43 22 7.0 3.9 | -30.5 -22.9 255 44 23 8.2 4.5
27000 -29.1 -20.4 255 41 21 7.1 3.9 | -28.1 -18.6 255 43 22 7.9 4.3
26000 -27.0 -16.6 255 40 20 7.1 3.9 | -25.8 -14.4 255 42 21 7.9 4.4
25000 -24.9 -12.8 255 38 20 7.1 3.9 | -23.4 -10.1 255 40 21 8.0 4.4
24000 -22.7 -8.9 255 37 19 7.6 4.2 | -21.1 -6.0 255 39 20 7.4 4.1
23000 -20.5 -4.9 255 35 18 7.7 4.2 | -18.9 -2.0 260 37 19 7.4 4.1
22000 -18.2 -0.8 255 34 18 7.7 4.2 | -16.7 1.9 265 36 18 7.5 4.1
21000 -15.8 3.6 255 32 17 8.2 4.5 | -14.6 5.7 265 35 18 7.0 3.9
20000 -13.4 7.9 255 30 16 8.3 4.5 | -12.6 9.3 270 34 17 7.1 3.9
19500 -12.2 10.0 255 29 15 8.3 4.5 | -11.5 11.3 270 34 17 7.1 3.9
19000 -11.0 12.2 255 28 14 9.1 5.0 | -10.5 13.1 270 33 17 7.7 4.2
18500 -9.5 14.9 255 27 14 9.4 5.2 | -9.3 15.3 275 32 17 7.9 4.4
18000 -8.1 17.4 255 26 14 9.4 5.2 | -8.1 17.4 275 31 16 8.0 4.4
17500 -6.7 19.9 255 25 13 9.3 5.1 | -6.9 19.6 275 31 16 8.6 4.7
17000 -4.6 23.7 260 24 13 9.3 5.1 | -5.0 23.0 275 30 15 8.5 4.7
16500 -3.2 26.2 260 23 12 9.2 5.0 | -3.8 25.2 275 29 15 8.2 4.5
16000 -1.9 28.6 260 22 11 9.2 5.0 | -2.5 27.5 275 28 14 8.3 4.5
15500 -0.5 31.1 260 21 11 9.4 5.2 | -1.3 29.7 275 26 14 8.0 4.4
15000 0.9 33.6 260 20 10 9.4 5.2 | -0.1 31.8 275 24 13 8.0 4.4
14500 2.3 36.1 260 19 10 9.0 4.9 | 1.0 33.8 275 22 12 7.1 3.9
14000 3.6 38.5 260 17 9 8.7 4.8 | 2.0 35.6 270 20 10 6.6 3.6
13500 4.9 40.8 260 16 8 8.3 4.6 | 2.9 37.2 265 18 9 6.0 3.3
13000 6.1 43.0 260 14 7 7.8 4.3 | 3.6 38.5 250 15 8 5.1 2.8
12500 7.3 45.1 260 13 7 7.6 4.2 | 4.3 39.7 230 12 6 5.4 2.9
12000 8.3 46.9 260 12 6 6.7 3.7 | 5.1 41.2 210 9 5 6.4 3.5
11500 9.3 48.7 255 11 5 6.4 3.5 | 5.8 42.4 175 8 4 7.1 3.9
11000 9.9 49.8 250 8 4 3.6 2.0 | 7.1 44.8 160 8 4 10.2 5.6
10500 10.4 50.7 230 5 3 3.1 1.7 | 8.6 47.5 150 9 4 5.2 2.9
10250 10.5 50.9 225 5 2 1.9 1.0 | 8.8 47.8 150 9 4 6.2 3.4
10000 10.5 50.9 210 2 1 2.6 1.4 | 9.7 49.5 150 9 4 13.3 7.3
9750 10.5 50.9 080 2 1 2.9 1.6 | 10.6 51.1 150 9 4 11.7 6.4
9500 10.6 51.1 065 5 2 4.3 2.4 | 11.4 52.5 145 8 4 11.2 6.1
9250 10.8 51.4 060 6 3 7.1 3.9 | 12.2 54.0 145 8 4 9.4 5.1
9000 11.4 52.5 060 6 3 9.5 5.2 | 12.9 55.2 145 8 4 10.2 5.6
8750 12.2 54.0 060 6 3 10.3 5.7 | 13.7 56.7 145 8 4 11.1 6.1
8500 12.9 55.2 060 6 3 10.1 5.5 | 14.5 58.1 145 8 4 10.3 5.7
8250 13.7 56.7 055 6 3 10.0 5.5 | 15.2 59.4 140 8 4 9.6 5.2
8000 14.4 57.9 055 6 3 10.1 5.6 | 15.9 60.6 140 8 4 9.7 5.3
7750 15.2 59.4 055 6 3 10.4 5.7 | 16.7 62.1 140 8 4 9.9 5.4
7500 16.0 60.8 055 6 3 10.3 5.6 | 17.4 63.3 140 8 4 10.0 5.5
7250 16.7 62.1 050 6 3 10.3 5.6 | 18.2 64.8 135 8 4 10.3 5.6
7000 17.5 63.5 050 6 3 10.0 5.5 | 18.9 66.0 135 8 4 10.0 5.5
6750 18.2 64.8 050 6 3 9.6 5.3 | 19.7 67.5 135 8 4 9.8 5.4
6500 19.0 66.2 045 6 3 10.6 5.8 | 20.4 68.7 135 8 4 10.4 5.7
6250 19.8 67.6 045 6 3 12.1 6.6 | 21.2 70.2 130 8 4 11.3 6.2
6000 20.6 69.1 045 6 3 9.3 5.1 | 22.0 71.6 130 8 4 9.7 5.3
5750 21.4 70.5 045 6 3 15.4 8.4 | 22.7 72.9 130 7 4 12.3 6.7
5500 23.2 73.8 040 6 3 33.4 18.3 | 24.0 75.2 125 7 4 21.0 11.5
________________________________________________________________________________
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.
CIN (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
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- Page last modified: Jun 3rd, 2013 13:59 UTC