National Weather Service Text Product
AFOS product SRGBOU
Dates interpreted at 00:00 UTCDisplaying AFOS PIL: SRGBOU
Product Timestamp: 2014-03-31 00:31 UTC
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171
UXUS97 KBOU 310031
SRGBOU
Soaring Forecast
National Weather Service Denver/Boulder, Colorado
1830 MDT Sunday, March 30, 2014
This forecast is for Monday, March 31, 2014:
If the trigger temperature of 46.0 F/7.8 C is reached...then
Thermal Soaring Index....................... Fair
Maximum rate of lift........................ 491 ft/min (2.5 m/s)
Maximum height of thermals.................. 12128 ft MSL (6841 ft AGL)
Forecast maximum temperature................... 54.0 F/12.7 C
Time of trigger temperature.................... 1000 MDT
Time of overdevelopment........................ 1800 MDT
Middle/high clouds during soaring window....... None
Surface winds during soaring window............ Between 20 mph and 30 mph
Height of the -3 thermal index................. 9945 ft MSL (4657 ft AGL)
Thermal soaring outlook for Tuesday 04/01...... Good
Wave Soaring Index............................. Poor
Wave Soaring Index trend (to 1800 MDT)......... Little change
Height of stable layer (12-18K ft MSL)......... None
Weak PVA/NVA (through 1800 MDT)................ Neither
Potential height of wave....................... 14405 ft MSL (9118 ft AGL)
Wave soaring outlook for Tuesday 04/01......... Fair
Remarks...
Sunrise/Sunset.................... 06:45:08 / 19:21:40 MDT
Total possible sunshine........... 12 hr 36 min 33 sec (756 min 33 sec)
Altitude of sun at 13:03:34 MDT... 54.59 degrees
Upper air data from numerical model forecast valid on 03/31/2014 at 0600 MDT
Freezing level.................. 6920 ft MSL (1633 ft AGL)
Convective condensation level... 16490 ft MSL (11203 ft AGL)
Lifted condensation level....... 15706 ft MSL (10419 ft AGL)
Lifted index.................... +3.2
K index......................... -4.2
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 -55.9 -68.6 255 50 26 0.9 0.5 M M M M M
45000 -54.6 -66.3 255 60 31 0.9 0.5 M M M M M
40000 -53.5 -64.3 255 58 30 0.7 0.4 M M M M M
38000 -53.1 -63.6 255 57 29 0.2 0.1 M M M M M
36000 -53.0 -63.4 260 58 30 0.2 0.1 M M M M M
34000 -52.8 -63.0 265 60 31 0.3 0.2 M M M M M
32000 -50.3 -58.5 270 63 32 4.9 2.7 M M M M M
30000 -47.4 -53.3 275 66 34 4.8 2.6 M M M M M
29000 -45.8 -50.4 275 65 34 5.5 3.0 27.4 81.3 11.5 M M
28000 -44.2 -47.6 280 64 33 5.5 3.0 25.7 78.2 10.3 M M
27000 -42.5 -44.5 280 62 32 5.5 3.0 24.1 75.3 9.2 M M
26000 -40.8 -41.4 280 59 30 6.9 3.8 22.6 72.7 8.2 M M
25000 -38.7 -37.7 280 52 27 6.8 3.7 21.4 70.5 7.3 M M
24000 -36.7 -34.1 280 44 23 6.8 3.7 20.3 68.6 6.5 M M
23000 -34.7 -30.5 275 37 19 6.2 3.4 19.3 66.7 5.7 M M
22000 -32.8 -27.0 270 29 15 6.2 3.4 17.9 64.2 4.7 M M
21000 -31.0 -23.8 265 21 11 6.3 3.5 16.7 62.0 3.7 M M
20000 -28.8 -19.8 260 15 8 8.5 4.7 15.8 60.4 3.0 M M
19500 -27.5 -17.5 265 14 7 8.5 4.7 15.6 60.0 2.8 M M
19000 -26.2 -15.2 275 13 7 8.5 4.7 15.3 59.6 2.6 M M
18500 -25.0 -13.0 280 12 6 8.6 4.7 15.1 59.3 2.5 M M
18000 -23.7 -10.7 290 11 6 8.9 4.9 15.0 59.0 2.3 M M
17500 -22.3 -8.1 295 12 6 9.4 5.1 14.9 58.8 2.3 M M
17000 -20.9 -5.6 300 13 7 9.4 5.2 14.8 58.7 2.2 M M
16500 -18.8 -1.8 305 16 8 9.0 4.9 14.7 58.4 2.1 M M
16000 -17.5 0.5 310 18 10 8.9 4.9 14.6 58.2 2.0 M M
15500 -16.2 2.8 310 21 11 8.1 4.5 14.3 57.8 1.8 M M
15000 -15.0 5.0 310 24 12 8.2 4.5 14.1 57.3 1.6 M M
14500 -13.8 7.2 310 26 13 8.2 4.5 13.8 56.9 1.3 M M
14000 -12.5 9.5 310 29 15 8.2 4.5 13.5 56.4 1.1 M M
13500 -11.3 11.7 310 32 17 8.0 4.4 13.3 55.9 0.9 M M
13000 -10.1 13.8 310 35 18 8.0 4.4 13.0 55.4 0.6 M M
12500 -9.0 15.8 310 39 20 7.1 3.9 12.6 54.8 0.3 M M
12000 -8.0 17.6 310 42 22 6.9 3.8 12.2 53.9 -0.2 474 2.4
11500 -7.0 19.4 305 46 23 5.8 3.2 11.7 53.0 -0.6 430 2.2
11000 -6.2 20.8 305 49 25 5.5 3.0 11.0 51.7 -1.3 391 2.0
10500 -5.4 22.3 305 52 27 4.2 2.3 10.2 50.4 -2.0 354 1.8
10250 -5.2 22.6 305 53 27 3.7 2.0 9.8 49.6 -2.5 338 1.7
10000 -4.9 23.2 300 54 28 4.2 2.3 9.3 48.7 -3.0 322 1.6
9750 -4.6 23.7 300 54 28 4.1 2.3 8.9 48.0 -3.4 306 1.6
9500 -4.3 24.3 300 54 28 3.6 2.0 8.4 47.1 -3.9 290 1.5
9250 -4.0 24.8 295 54 28 3.6 2.0 7.9 46.2 -4.4 275 1.4
9000 -3.8 25.2 295 54 28 3.4 1.9 7.4 45.4 -4.8 260 1.3
8750 -3.5 25.7 295 54 28 3.9 2.1 6.9 44.5 -5.3 245 1.2
8500 -3.2 26.2 295 52 27 4.6 2.5 6.5 43.7 -5.8 228 1.2
8250 -2.9 26.8 290 50 26 3.7 2.0 6.1 43.0 -6.2 211 1.1
8000 -2.6 27.3 290 48 24 6.7 3.7 5.7 42.2 -6.6 194 1.0
7750 -1.9 28.6 290 45 23 8.8 4.9 5.6 42.1 -6.7 167 0.9
7500 -1.4 29.5 290 43 22 7.4 4.0 5.4 41.8 -6.9 143 0.7
7250 -0.8 30.6 290 41 21 7.8 4.3 5.3 41.5 -7.1 118 0.6
7000 -0.2 31.6 290 39 20 7.6 4.2 5.1 41.2 -7.3 94 0.5
6750 0.4 32.7 290 36 19 8.1 4.5 5.0 41.0 -7.4 69 0.4
6500 1.0 33.8 285 34 17 8.5 4.7 4.9 40.8 -7.6 43 0.2
6250 1.6 34.9 285 31 16 8.3 4.6 4.8 40.6 -7.7 16 0.1
6000 2.2 36.0 285 28 14 7.9 4.3 4.7 40.4 -7.8 M M
5750 2.8 37.0 285 24 12 8.3 4.5 4.5 40.1 -8.0 M M
5500 3.4 38.1 285 19 10 6.0 3.3 4.4 39.9 -8.2 M M
* * * * * * Numerical weather prediction model forecast data valid * * * * * *
03/31/2014 at 0900 MDT | 03/31/2014 at 1200 MDT
|
K index... -4.7 LI... +4.8 | K index... +2.5 LI... +5.1
CAPE... 0.0 CIN... -0.8 | CAPE... 0.0 CIN... M
|
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 -56.3 -69.3 260 50 26 1.3 0.7 | -56.5 -69.7 255 48 25 1.4 0.7
45000 -54.3 -65.7 255 54 28 1.3 0.7 | -54.4 -65.9 260 62 32 1.3 0.7
40000 -53.4 -64.1 260 60 31 0.5 0.3 | -55.3 -67.5 260 68 35 -0.9 -0.5
38000 -53.2 -63.8 260 62 32 -1.0 -0.6 | -55.7 -68.3 260 69 36 0.4 0.2
36000 -53.8 -64.8 265 62 32 -1.0 -0.5 | -55.6 -68.1 265 66 34 0.2 0.1
34000 -54.4 -65.9 275 63 33 -0.8 -0.4 | -55.4 -67.7 265 64 33 0.3 0.2
32000 -51.8 -61.2 275 65 34 5.4 2.9 | -52.9 -63.2 270 62 32 5.5 3.0
30000 -48.5 -55.3 280 68 35 5.4 3.0 | -49.1 -56.4 270 62 32 5.8 3.2
29000 -46.9 -52.4 280 66 34 5.6 3.1 | -47.1 -52.8 275 61 31 6.9 3.8
28000 -45.2 -49.4 285 64 33 5.6 3.1 | -45.1 -49.2 275 59 31 6.9 3.8
27000 -43.5 -46.3 285 62 32 5.6 3.1 | -43.0 -45.4 275 58 30 6.9 3.8
26000 -41.7 -43.1 285 58 30 6.9 3.8 | -40.9 -41.6 280 56 29 7.0 3.8
25000 -39.7 -39.5 285 53 27 6.8 3.7 | -38.8 -37.8 280 53 27 7.0 3.8
24000 -37.6 -35.7 280 47 24 6.8 3.7 | -36.7 -34.1 280 50 26 7.0 3.9
23000 -35.5 -31.9 275 42 22 8.0 4.4 | -34.5 -30.1 285 47 24 7.7 4.2
22000 -33.1 -27.6 275 36 19 7.9 4.3 | -32.2 -26.0 285 46 23 7.7 4.2
21000 -30.8 -23.4 275 30 16 7.9 4.3 | -29.9 -21.8 285 44 23 7.7 4.2
20000 -28.3 -18.9 275 27 14 8.4 4.6 | -27.7 -17.9 290 43 22 7.2 3.9
19500 -27.1 -16.8 280 27 14 8.4 4.6 | -26.6 -15.9 290 43 22 7.2 3.9
19000 -25.8 -14.4 285 27 14 8.4 4.6 | -25.6 -14.1 290 43 22 7.2 3.9
18500 -24.5 -12.1 290 27 14 8.4 4.6 | -24.5 -12.1 290 42 22 7.2 4.0
18000 -23.3 -9.9 295 27 14 8.2 4.5 | -23.4 -10.1 295 42 22 6.5 3.6
17500 -22.1 -7.8 295 29 15 8.0 4.4 | -22.5 -8.5 295 43 22 6.3 3.4
17000 -20.9 -5.6 300 30 16 8.0 4.4 | -21.6 -6.9 295 43 22 6.2 3.4
16500 -19.7 -3.5 300 32 16 8.0 4.4 | -20.7 -5.3 295 43 22 5.8 3.2
16000 -18.5 -1.3 305 34 17 8.1 4.4 | -19.8 -3.6 300 43 22 5.9 3.2
15500 -16.8 1.8 305 37 19 7.3 4.0 | -18.5 -1.3 300 43 22 5.9 3.3
15000 -15.7 3.7 305 40 20 7.3 4.0 | -17.7 0.1 300 42 22 5.9 3.2
14500 -14.6 5.7 305 42 21 6.9 3.8 | -16.8 1.8 305 42 22 5.6 3.1
14000 -13.6 7.5 305 43 22 6.9 3.8 | -16.0 3.2 305 42 22 5.7 3.1
13500 -12.6 9.3 310 45 23 6.8 3.7 | -15.0 5.0 310 41 21 6.8 3.7
13000 -11.6 11.1 310 46 24 6.9 3.8 | -14.0 6.8 310 40 21 6.7 3.7
12500 -10.6 12.9 310 48 25 6.1 3.3 | -13.0 8.6 315 38 20 7.4 4.1
12000 -9.7 14.5 310 49 25 6.1 3.4 | -11.9 10.6 315 36 19 7.4 4.0
11500 -8.8 16.2 310 50 26 5.7 3.1 | -10.8 12.6 315 34 17 7.2 3.9
11000 -8.0 17.6 310 51 26 5.8 3.2 | -9.8 14.4 320 31 16 7.1 3.9
10500 -7.2 19.0 310 50 26 4.6 2.5 | -8.8 16.2 320 28 15 6.5 3.6
10250 -6.9 19.6 310 50 26 4.0 2.2 | -8.3 17.1 320 27 14 5.7 3.1
10000 -6.5 20.3 310 50 26 6.6 3.6 | -7.8 18.0 320 26 13 9.0 4.9
9750 -6.0 21.2 310 49 25 6.9 3.8 | -7.0 19.4 320 24 12 10.4 5.7
9500 -5.6 21.9 305 47 24 4.3 2.3 | -6.4 20.5 320 23 12 8.2 4.5
9250 -5.2 22.6 305 46 24 5.4 3.0 | -5.7 21.7 320 22 11 8.7 4.7
9000 -4.9 23.2 305 45 23 3.5 1.9 | -5.1 22.8 320 21 11 9.0 5.0
8750 -4.7 23.5 305 44 22 4.5 2.5 | -4.4 24.1 320 20 10 9.8 5.4
8500 -4.2 24.4 300 41 21 7.1 3.9 | -3.6 25.5 320 20 10 9.8 5.4
8250 -3.7 25.3 300 39 20 5.8 3.2 | -2.9 26.8 320 20 10 10.0 5.5
8000 -3.2 26.2 300 36 19 8.2 4.5 | -2.1 28.2 320 19 10 11.0 6.0
7750 -2.5 27.5 300 33 17 9.6 5.3 | -1.3 29.7 320 19 10 10.4 5.7
7500 -1.9 28.6 300 31 16 8.4 4.6 | -0.6 30.9 320 19 10 9.5 5.2
7250 -1.2 29.8 300 29 15 9.0 4.9 | 0.2 32.4 320 19 10 9.9 5.4
7000 -0.5 31.1 300 28 14 10.4 5.7 | 0.9 33.6 320 18 10 9.9 5.4
6750 0.3 32.5 300 26 13 9.9 5.4 | 1.6 34.9 320 18 9 10.1 5.6
6500 0.9 33.6 300 24 12 8.3 4.6 | 2.4 36.3 320 18 9 10.6 5.8
6250 1.6 34.9 300 23 12 9.9 5.4 | 3.2 37.8 320 18 9 11.4 6.2
6000 2.4 36.3 300 21 11 11.2 6.2 | 4.1 39.4 320 17 9 11.6 6.3
5750 3.2 37.8 300 19 10 10.3 5.6 | 5.0 41.0 315 17 9 11.7 6.4
5500 4.0 39.2 300 17 9 12.1 6.6 | 6.0 42.8 320 16 8 18.8 10.3
03/31/2014 at 1500 MDT | 03/31/2014 at 1800 MDT
|
K index... +1.7 LI... +3.6 | K index... +6.1 LI... +2.9
CAPE... 0.0 CIN... M | CAPE... 0.0 CIN... M
|
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 -55.9 -68.6 265 57 30 0.1 0.0 | -55.7 -68.3 270 55 28 -0.4 -0.2
45000 -55.8 -68.4 265 69 36 0.1 0.0 | -56.3 -69.3 270 70 36 -0.4 -0.2
40000 -56.3 -69.3 265 76 39 -0.4 -0.2 | -56.5 -69.7 270 84 43 -0.1 -0.1
38000 -56.4 -69.5 265 77 40 1.3 0.7 | -56.5 -69.7 270 88 45 1.1 0.6
36000 -55.6 -68.1 265 73 38 1.2 0.6 | -55.9 -68.6 270 87 45 1.0 0.6
34000 -54.9 -66.8 270 69 36 1.1 0.6 | -55.2 -67.4 270 87 45 0.9 0.5
32000 -52.7 -62.9 270 68 35 4.5 2.5 | -52.9 -63.2 270 82 42 4.5 2.5
30000 -49.6 -57.3 270 68 35 5.1 2.8 | -49.9 -57.8 265 77 39 5.6 3.1
29000 -47.7 -53.9 270 66 34 6.6 3.6 | -47.7 -53.9 265 75 38 7.5 4.1
28000 -45.8 -50.4 265 64 33 6.6 3.6 | -45.5 -49.9 265 73 38 7.5 4.1
27000 -43.8 -46.8 265 63 32 6.6 3.6 | -43.2 -45.8 265 71 37 7.5 4.1
26000 -41.6 -42.9 265 60 31 7.7 4.2 | -41.0 -41.8 265 68 35 7.4 4.1
25000 -39.3 -38.7 265 56 29 7.8 4.3 | -38.8 -37.8 265 64 33 7.4 4.1
24000 -37.0 -34.6 265 52 27 7.8 4.3 | -36.6 -33.9 265 60 31 7.4 4.1
23000 -34.6 -30.3 270 49 25 8.1 4.5 | -34.3 -29.7 265 56 29 7.9 4.3
22000 -32.2 -26.0 270 47 24 8.1 4.5 | -31.9 -25.4 265 53 27 7.9 4.3
21000 -29.7 -21.5 270 44 23 8.2 4.5 | -29.6 -21.3 265 49 25 8.1 4.4
20000 -27.5 -17.5 275 42 22 7.1 3.9 | -27.5 -17.5 265 46 24 6.4 3.5
19500 -26.4 -15.5 275 41 21 7.1 3.9 | -26.6 -15.9 265 44 23 6.4 3.5
19000 -25.4 -13.7 275 40 21 7.1 3.9 | -25.6 -14.1 265 42 22 6.4 3.5
18500 -24.3 -11.7 275 39 20 7.2 3.9 | -24.7 -12.5 265 40 21 6.4 3.5
18000 -23.3 -9.9 280 38 19 6.4 3.5 | -23.7 -10.7 265 38 20 6.4 3.5
17500 -22.3 -8.1 280 37 19 6.3 3.5 | -22.8 -9.0 265 37 19 6.4 3.5
17000 -21.4 -6.5 280 35 18 6.1 3.4 | -21.8 -7.2 265 35 18 6.7 3.7
16500 -20.5 -4.9 280 35 18 5.8 3.2 | -20.7 -5.3 265 34 17 7.2 3.9
16000 -19.6 -3.3 285 34 17 5.8 3.2 | -19.7 -3.5 265 33 17 7.2 4.0
15500 -18.7 -1.7 285 33 17 6.5 3.6 | -18.6 -1.5 265 31 16 7.8 4.3
15000 -17.3 0.9 290 32 16 6.6 3.6 | -16.8 1.8 265 29 15 7.8 4.3
14500 -16.3 2.7 290 31 16 6.8 3.7 | -15.7 3.7 265 28 14 7.8 4.3
14000 -15.3 4.5 295 31 16 6.9 3.8 | -14.5 5.9 265 26 13 7.9 4.3
13500 -14.2 6.4 295 30 16 7.6 4.2 | -13.3 8.1 270 24 13 8.1 4.5
13000 -13.1 8.4 295 29 15 7.6 4.2 | -12.1 10.2 270 23 12 8.1 4.4
12500 -11.9 10.6 300 28 15 7.8 4.3 | -10.9 12.4 270 21 11 7.9 4.3
12000 -10.8 12.6 300 27 14 7.8 4.3 | -9.7 14.5 275 20 10 7.9 4.3
11500 -9.7 14.5 305 24 12 7.2 3.9 | -8.6 16.5 280 18 9 7.4 4.1
11000 -8.6 16.5 305 21 11 7.2 4.0 | -7.5 18.5 285 17 9 7.3 4.0
10500 -7.6 18.3 305 19 10 7.2 3.9 | -6.5 20.3 290 15 8 6.7 3.7
10250 -7.1 19.2 310 18 9 6.1 3.4 | -6.0 21.2 295 14 7 6.5 3.6
10000 -6.5 20.3 310 17 9 11.7 6.4 | -5.4 22.3 300 13 7 10.1 5.6
9750 -5.5 22.1 310 16 8 13.0 7.1 | -4.6 23.7 305 12 6 10.5 5.7
9500 -4.7 23.5 310 16 8 8.8 4.8 | -3.9 25.0 310 12 6 7.8 4.3
9250 -4.0 24.8 310 16 8 10.0 5.5 | -3.3 26.1 315 11 6 8.3 4.6
9000 -3.3 26.1 310 15 8 9.4 5.2 | -2.7 27.1 320 11 5 9.1 5.0
8750 -2.6 27.3 310 15 8 9.9 5.4 | -2.0 28.4 320 10 5 10.1 5.5
8500 -1.8 28.8 315 15 8 10.5 5.7 | -1.2 29.8 325 10 5 9.7 5.3
8250 -1.0 30.2 315 15 8 10.3 5.7 | -0.5 31.1 325 10 5 9.9 5.4
8000 -0.3 31.5 315 15 8 10.2 5.6 | 0.2 32.4 325 10 5 10.1 5.5
7750 0.5 32.9 315 15 8 9.7 5.3 | 1.0 33.8 325 10 5 9.6 5.3
7500 1.2 34.2 315 15 8 9.3 5.1 | 1.7 35.1 330 10 5 9.0 4.9
7250 1.9 35.4 315 15 7 10.1 5.6 | 2.4 36.3 330 10 5 10.1 5.5
7000 2.7 36.9 315 14 7 11.0 6.1 | 3.2 37.8 330 10 5 11.2 6.2
6750 3.5 38.3 315 14 7 10.0 5.5 | 4.0 39.2 330 10 5 9.6 5.3
6500 4.2 39.6 315 14 7 9.8 5.4 | 4.7 40.5 330 10 5 9.0 4.9
6250 5.0 41.0 315 14 7 11.1 6.1 | 5.4 41.7 330 9 5 10.6 5.8
6000 5.9 42.6 315 13 7 11.4 6.3 | 6.2 43.2 330 9 5 11.1 6.1
5750 6.7 44.1 315 13 7 11.5 6.3 | 7.0 44.6 330 9 5 10.5 5.8
5500 7.7 45.9 315 13 7 18.8 10.3 | 7.8 46.0 330 9 5 12.6 6.9
________________________________________________________________________________
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.
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