Soaring Guidance
Issued by NWS Denver/Boulder, CO
Issued by NWS Denver/Boulder, CO
870
UXUS97 KBOU 081401
SRGBOU
Soaring Forecast
National Weather Service Denver/Boulder, Colorado
0700 MST Friday, November 8, 2024
This forecast is for Friday, November 8, 2024:
If the trigger temperature of 46.2 F/7.9 C is reached...then
Thermal Soaring Index....................... Poor
Maximum rate of lift........................ 0 ft/min (0.0 m/s)
Maximum height of thermals.................. 5340 ft MSL (0 ft AGL)
Forecast maximum temperature................... 32.0 F/0.5 C
Time of trigger temperature.................... None
Time of overdevelopment........................ None
Middle/high clouds during soaring window....... Overcast opaque high
Surface winds during soaring window............ 20 mph or less
Height of the -3 thermal index................. None
Thermal soaring outlook for Saturday 11/09..... Poor
Wave Soaring Index............................. Poor
Wave Soaring Index trend (to 1700 MST)......... No change. Heavy snow in area.
Height of stable layer (12-18K ft MSL)......... None
Weak PVA/NVA (through 1700 MST)................ Neither
Potential height of wave....................... 30228 ft MSL (24888 ft AGL)
Wave soaring outlook for Saturday 11/09........ Poor
Remarks... North flow at ridgetop all day Saturday.
Sunrise/Sunset.................... 06:37:03 / 16:49:25 MST
Total possible sunshine........... 10 hr 12 min 21 sec (612 min 21 sec)
Altitude of sun at 11:43:14 MST... 33.22 degrees
Upper air data from numerical model forecast valid on 11/08/2024 at 0500 MST
Freezing level.................. 5661 ft MSL (321 ft AGL)
Convective condensation level... 11353 ft MSL (6013 ft AGL)
Lifted condensation level....... 6611 ft MSL (1271 ft AGL)
Lifted index.................... +15.4
K index......................... +12.7
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 -58.1 -72.6 225 5 3 3.3 1.8 M M M M M
45000 -53.2 -63.8 115 4 2 3.6 2.0 M M M M M
40000 -47.7 -53.9 110 9 4 3.7 2.0 M M M M M
38000 -46.1 -51.0 150 16 8 2.0 1.1 M M M M M
36000 -44.8 -48.6 170 33 17 2.0 1.1 M M M M M
34000 -43.9 -47.0 175 52 27 -0.2 -0.1 M M M M M
32000 -44.1 -47.4 170 78 40 -0.3 -0.2 M M M M M
30000 -43.2 -45.8 165 97 50 7.0 3.8 33.5 92.3 25.1 M M
29000 -41.1 -42.0 165 95 49 7.2 3.9 32.3 90.2 24.5 M M
28000 -39.0 -38.2 160 93 48 7.2 3.9 31.3 88.4 24.1 M M
27000 -36.8 -34.2 160 91 47 7.8 4.3 30.5 86.9 23.7 M M
26000 -34.3 -29.7 160 84 43 8.4 4.6 29.9 85.8 23.5 M M
25000 -31.8 -25.2 160 76 39 8.5 4.6 29.4 84.9 23.4 M M
24000 -29.2 -20.6 160 69 36 8.1 4.4 29.0 84.2 23.3 M M
23000 -27.4 -17.3 160 63 32 5.9 3.2 27.6 81.7 22.5 M M
22000 -25.6 -14.1 160 56 29 5.9 3.2 26.2 79.2 21.6 M M
21000 -23.9 -11.0 155 49 25 6.3 3.5 24.9 76.9 20.7 M M
20000 -21.4 -6.5 155 44 23 6.6 3.6 23.4 74.2 19.7 M M
19500 -20.4 -4.7 150 42 22 6.6 3.6 22.9 73.2 19.4 M M
19000 -19.5 -3.1 150 40 21 6.7 3.7 22.4 72.3 19.0 M M
18500 -18.5 -1.3 150 38 19 5.6 3.1 21.8 71.2 18.6 M M
18000 -17.7 0.1 150 35 18 5.6 3.1 21.1 69.9 18.1 M M
17500 -16.9 1.6 150 32 16 5.2 2.9 20.4 68.7 17.6 M M
17000 -16.2 2.8 155 29 15 4.7 2.6 19.5 67.1 16.9 M M
16500 -15.5 4.1 160 26 13 4.7 2.6 18.6 65.6 16.2 M M
16000 -14.6 5.7 165 23 12 6.8 3.7 18.0 64.4 15.7 M M
15500 -13.6 7.5 160 20 10 6.5 3.6 17.5 63.4 15.3 M M
15000 -12.6 9.3 160 17 9 7.5 4.1 17.0 62.6 15.0 M M
14500 -11.4 11.5 150 16 8 7.5 4.1 16.6 61.9 14.8 M M
14000 -10.3 13.5 145 16 8 7.6 4.1 16.2 61.2 14.5 M M
13500 -9.2 15.4 135 17 9 7.6 4.2 15.9 60.6 14.3 M M
13000 -8.1 17.4 130 18 9 6.0 3.3 15.5 59.9 14.0 M M
12500 -7.3 18.9 130 19 10 5.2 2.9 14.7 58.5 13.3 M M
12000 -6.6 20.1 130 19 10 3.8 2.1 14.0 57.2 12.6 M M
11500 -6.3 20.7 135 17 9 2.9 1.6 12.8 55.1 11.6 M M
11000 -5.9 21.4 135 15 8 3.4 1.8 11.8 53.2 10.6 M M
10500 -5.4 22.3 145 12 6 3.9 2.1 10.8 51.4 9.7 M M
10250 -5.1 22.8 150 10 5 2.6 1.4 10.3 50.5 9.2 M M
10000 -5.0 23.0 155 9 5 1.0 0.6 9.6 49.3 8.6 M M
9750 -4.9 23.2 160 8 4 4.1 2.2 9.0 48.3 8.1 M M
9500 -4.5 23.9 170 7 4 6.2 3.4 8.7 47.7 7.8 M M
9250 -4.0 24.8 180 6 3 5.3 2.9 8.4 47.1 7.5 M M
9000 -3.6 25.5 185 6 3 4.9 2.7 8.0 46.5 7.2 M M
8750 -3.3 26.1 190 5 3 4.6 2.5 7.6 45.8 6.8 M M
8500 -3.0 26.6 190 5 3 4.4 2.4 7.2 45.0 6.4 M M
8250 -2.7 27.1 190 5 3 3.5 1.9 6.8 44.2 6.0 M M
8000 -2.5 27.5 190 5 3 3.0 1.7 6.3 43.3 5.5 M M
7750 -2.2 28.0 190 5 3 2.2 1.2 5.7 42.3 5.0 M M
7500 -2.2 28.0 195 5 3 1.5 0.8 5.1 41.2 4.4 M M
7250 -2.0 28.4 200 5 3 2.1 1.1 4.5 40.1 3.8 M M
7000 -1.9 28.6 205 5 3 2.0 1.1 3.9 39.0 3.2 M M
6750 -1.8 28.8 210 5 3 2.4 1.3 3.3 38.0 2.6 M M
6500 -1.5 29.3 225 5 2 4.0 2.2 2.8 37.1 2.1 M M
6250 -1.2 29.8 235 4 2 4.8 2.7 2.4 36.4 1.7 M M
6000 -0.9 30.4 250 4 2 4.6 2.5 2.0 35.7 1.3 M M
5750 -0.5 31.1 260 3 2 7.0 3.9 1.7 35.1 1.0 M M
5500 0.2 32.4 255 2 1 10.8 5.9 1.7 35.0 0.9 M M
* * * * * * Numerical weather prediction model forecast data valid * * * * * *
11/08/2024 at 0800 MST | 11/08/2024 at 1100 MST
|
CAPE... +1.9 LI... +4.7 | CAPE... +3.8 LI... +5.9
CINH... 0.0 K Index... +16.7 | CINH... -0.1 K Index... +16.5
|
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 -58.0 -72.4 250 6 3 3.2 1.8 | -58.1 -72.6 240 6 3 3.3 1.8
45000 -53.1 -63.6 160 3 2 3.3 1.8 | -53.3 -63.9 120 3 1 3.3 1.8
40000 -48.1 -54.6 135 14 7 3.3 1.8 | -48.0 -54.4 150 13 7 3.3 1.8
38000 -46.8 -52.2 155 24 12 1.4 0.8 | -47.5 -53.5 155 25 13 -0.2 -0.1
36000 -45.9 -50.6 165 36 18 1.4 0.8 | -47.6 -53.7 155 40 21 -0.2 -0.1
34000 -45.3 -49.5 165 49 25 0.0 0.0 | -47.3 -53.1 155 51 26 2.7 1.5
32000 -45.3 -49.5 160 63 33 0.0 0.0 | -45.6 -50.1 145 53 27 2.8 1.5
30000 -43.8 -46.8 155 74 38 8.6 4.7 | -42.4 -44.3 135 54 28 8.9 4.9
29000 -41.2 -42.2 155 72 37 8.8 4.8 | -39.8 -39.6 135 53 27 8.8 4.8
28000 -38.5 -37.3 150 70 36 8.8 4.8 | -37.1 -34.8 135 52 27 8.8 4.8
27000 -35.9 -32.6 150 68 35 8.4 4.6 | -34.5 -30.1 135 51 26 8.7 4.8
26000 -33.4 -28.1 150 66 34 8.2 4.5 | -31.9 -25.4 135 49 25 8.7 4.8
25000 -31.0 -23.8 150 64 33 8.2 4.5 | -29.3 -20.7 130 47 24 8.7 4.8
24000 -28.5 -19.3 145 63 32 8.1 4.4 | -26.8 -16.2 130 45 23 8.1 4.4
23000 -26.2 -15.2 140 59 31 7.8 4.3 | -24.5 -12.1 130 44 23 7.8 4.3
22000 -23.9 -11.0 135 57 29 7.8 4.3 | -22.2 -8.0 130 43 22 7.8 4.3
21000 -21.6 -6.9 130 54 28 6.6 3.6 | -19.9 -3.8 130 42 22 6.4 3.5
20000 -19.8 -3.6 125 52 27 6.2 3.4 | -18.1 -0.6 125 41 21 6.4 3.5
19500 -18.4 -1.1 120 50 26 6.2 3.4 | -17.1 1.2 125 41 21 6.4 3.5
19000 -17.5 0.5 115 49 25 6.3 3.5 | -16.2 2.8 125 41 21 6.5 3.5
18500 -16.6 2.1 115 47 24 5.5 3.0 | -15.3 4.5 120 41 21 6.8 3.7
18000 -15.8 3.6 115 44 23 5.6 3.1 | -14.2 6.4 120 42 22 7.0 3.8
17500 -15.0 5.0 110 41 21 5.0 2.8 | -13.2 8.2 120 43 22 7.0 3.8
17000 -14.3 6.3 110 38 20 4.6 2.5 | -12.2 10.0 115 43 22 6.5 3.5
16500 -13.6 7.5 105 35 18 4.6 2.5 | -10.8 12.6 115 44 23 6.1 3.3
16000 -12.9 8.8 100 32 17 5.3 2.9 | -10.1 13.8 115 44 23 4.4 2.4
15500 -12.1 10.2 095 31 16 5.3 2.9 | -9.5 14.9 110 44 22 4.7 2.6
15000 -11.4 11.5 095 29 15 4.8 2.6 | -8.9 16.0 110 43 22 2.4 1.3
14500 -10.7 12.7 090 26 13 4.8 2.6 | -8.6 16.5 105 41 21 2.6 1.4
14000 -10.0 14.0 090 24 12 4.7 2.6 | -8.2 17.2 105 40 20 2.7 1.5
13500 -9.3 15.3 090 23 12 4.6 2.5 | -7.8 18.0 105 38 19 2.7 1.5
13000 -8.6 16.5 085 22 11 5.9 3.3 | -7.3 18.9 100 36 18 3.6 2.0
12500 -7.6 18.3 090 21 11 6.4 3.5 | -6.7 19.9 100 33 17 4.0 2.2
12000 -6.7 19.9 090 21 11 6.6 3.6 | -6.2 20.8 095 31 16 3.9 2.1
11500 -5.7 21.7 090 20 10 6.7 3.7 | -5.6 21.9 090 29 15 3.8 2.1
11000 -4.8 23.4 090 19 10 4.7 2.6 | -5.1 22.8 080 27 14 2.7 1.5
10500 -4.2 24.4 090 17 8 4.2 2.3 | -4.8 23.4 075 23 12 2.3 1.2
10250 -3.9 25.0 090 15 8 2.7 1.5 | -4.6 23.7 070 21 11 1.9 1.0
10000 -3.9 25.0 090 14 7 -0.2 -0.1 | -4.5 23.9 070 21 11 0.8 0.5
9750 -3.9 25.0 090 12 6 0.2 0.1 | -4.5 23.9 065 19 10 0.6 0.3
9500 -3.9 25.0 085 9 5 1.1 0.6 | -4.4 24.1 055 17 9 0.6 0.4
9250 -3.8 25.2 080 7 3 1.2 0.6 | -4.4 24.1 040 16 8 1.3 0.7
9000 -3.7 25.3 070 5 3 1.3 0.7 | -4.2 24.4 030 15 8 2.4 1.3
8750 -3.6 25.5 055 4 2 3.4 1.9 | -4.0 24.8 025 15 8 4.0 2.2
8500 -3.2 26.2 035 4 2 5.2 2.8 | -3.6 25.5 020 14 7 5.3 2.9
8250 -2.9 26.8 015 4 2 2.7 1.5 | -3.3 26.1 015 13 7 3.6 2.0
8000 -2.8 27.0 005 4 2 1.1 0.6 | -3.1 26.4 010 13 7 2.1 1.2
7750 -2.7 27.1 355 4 2 2.6 1.4 | -2.9 26.8 005 13 7 3.6 2.0
7500 -2.4 27.7 340 5 2 2.6 1.4 | -2.6 27.3 005 13 6 3.4 1.9
7250 -2.3 27.9 335 5 3 1.5 0.8 | -2.4 27.7 360 12 6 1.6 0.9
7000 -2.2 28.0 330 6 3 0.6 0.3 | -2.3 27.9 360 12 6 1.0 0.5
6750 -2.1 28.2 330 7 3 4.0 2.2 | -2.2 28.0 360 12 6 2.5 1.4
6500 -1.7 28.9 330 7 3 5.2 2.9 | -2.0 28.4 005 10 5 4.1 2.2
6250 -1.5 29.3 335 6 3 2.7 1.5 | -1.7 28.9 005 8 4 4.1 2.3
6000 -1.2 29.8 345 6 3 3.1 1.7 | -1.4 29.5 005 7 3 3.2 1.8
5750 -0.9 30.4 360 6 3 7.0 3.8 | -1.1 30.0 010 5 3 6.8 3.7
5500 -0.1 31.8 005 5 3 15.0 8.2 | -0.3 31.5 005 4 2 16.0 8.8
11/08/2024 at 1400 MST | 11/08/2024 at 1700 MST
|
CAPE... +2.8 LI... +8.1 | CAPE... +0.4 LI... +8.8
CINH... 0.0 K Index... +12.7 | CINH... -0.1 K Index... +11.7
|
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 -57.8 -72.0 235 8 4 3.3 1.8 | -58.6 -73.5 255 13 7 3.4 1.9
45000 -52.8 -63.0 155 1 0 3.5 1.9 | -53.3 -63.9 285 4 2 4.3 2.4
40000 -47.4 -53.3 140 8 4 3.3 1.8 | -46.6 -51.9 060 3 1 4.2 2.3
38000 -47.1 -52.8 140 24 13 -0.7 -0.4 | -45.8 -50.4 120 17 9 0.3 0.2
36000 -47.5 -53.5 140 46 24 -0.7 -0.4 | -45.6 -50.1 125 37 19 0.3 0.2
34000 -47.1 -52.8 135 65 33 4.2 2.3 | -45.1 -49.2 125 54 28 2.7 1.5
32000 -44.5 -48.1 135 75 38 4.4 2.4 | -43.4 -46.1 120 61 31 2.8 1.5
30000 -41.4 -42.5 130 80 41 7.4 4.1 | -40.5 -40.9 115 64 33 7.9 4.4
29000 -38.6 -37.5 130 72 37 7.6 4.2 | -38.1 -36.6 110 60 31 7.9 4.4
28000 -36.3 -33.3 130 67 34 7.6 4.2 | -35.8 -32.4 110 57 29 8.0 4.4
27000 -34.0 -29.2 130 61 31 8.0 4.4 | -33.4 -28.1 110 53 28 7.7 4.2
26000 -31.7 -25.1 125 56 29 8.0 4.4 | -31.1 -24.0 110 50 26 7.7 4.2
25000 -29.3 -20.7 125 51 26 8.0 4.4 | -28.8 -19.8 105 47 24 7.7 4.2
24000 -26.9 -16.4 125 47 24 8.2 4.5 | -26.6 -15.9 105 44 23 7.9 4.4
23000 -24.4 -11.9 125 45 23 8.3 4.6 | -24.1 -11.4 100 41 21 8.2 4.5
22000 -22.0 -7.6 120 43 22 8.4 4.6 | -21.7 -7.1 090 39 20 8.2 4.5
21000 -19.6 -3.3 120 41 21 6.9 3.8 | -19.4 -2.9 085 37 19 6.9 3.8
20000 -17.6 0.3 120 40 20 6.8 3.7 | -17.5 0.5 080 35 18 6.4 3.5
19500 -16.6 2.1 120 39 20 6.8 3.7 | -16.5 2.3 080 34 18 6.5 3.5
19000 -15.6 3.9 125 38 20 6.8 3.7 | -15.6 3.9 075 33 17 6.5 3.5
18500 -14.6 5.7 125 37 19 6.3 3.4 | -14.6 5.7 075 33 17 6.5 3.6
18000 -13.7 7.3 125 35 18 5.9 3.2 | -13.7 7.3 075 32 16 6.5 3.6
17500 -12.9 8.8 125 34 17 5.9 3.2 | -12.7 9.1 075 31 16 6.7 3.7
17000 -12.0 10.4 125 32 16 5.7 3.1 | -11.9 10.6 070 29 15 5.0 2.7
16500 -11.2 11.8 125 30 16 5.7 3.1 | -10.8 12.6 070 26 14 5.2 2.8
16000 -10.4 13.3 125 29 15 5.6 3.0 | -10.1 13.8 070 24 12 3.6 2.0
15500 -9.2 15.4 120 27 14 5.6 3.1 | -9.6 14.7 070 22 11 3.8 2.1
15000 -8.5 16.7 120 26 14 4.2 2.3 | -9.1 15.6 070 21 11 3.0 1.7
14500 -7.9 17.8 120 26 13 4.3 2.4 | -8.6 16.5 075 20 10 2.9 1.6
14000 -7.3 18.9 115 25 13 2.7 1.5 | -8.2 17.2 075 19 10 2.0 1.1
13500 -7.0 19.4 115 25 13 2.1 1.2 | -8.0 17.6 070 18 9 1.3 0.7
13000 -6.7 19.9 115 24 13 1.3 0.7 | -7.8 18.0 070 17 9 1.3 0.7
12500 -6.6 20.1 115 23 12 0.8 0.4 | -7.6 18.3 065 14 7 1.4 0.8
12000 -6.5 20.3 115 22 11 0.7 0.4 | -7.4 18.7 055 12 6 1.8 1.0
11500 -6.4 20.5 110 20 10 0.8 0.4 | -7.1 19.2 040 11 6 2.4 1.3
11000 -6.2 20.8 110 18 9 2.1 1.1 | -6.7 19.9 030 11 6 2.5 1.4
10500 -5.8 21.6 100 16 8 3.3 1.8 | -6.3 20.7 030 12 6 2.7 1.5
10250 -5.5 22.1 090 15 8 2.6 1.4 | -6.1 21.0 030 12 6 2.6 1.4
10000 -5.4 22.3 090 15 8 1.5 0.8 | -6.0 21.2 025 12 6 2.4 1.3
9750 -5.2 22.6 085 15 8 4.2 2.3 | -5.7 21.7 025 12 6 4.0 2.2
9500 -4.8 23.4 075 14 7 6.4 3.5 | -5.4 22.3 025 13 7 5.3 2.9
9250 -4.4 24.1 060 15 8 5.0 2.7 | -5.0 23.0 030 13 7 4.7 2.6
9000 -4.1 24.6 055 15 8 2.9 1.6 | -4.7 23.5 035 14 7 3.8 2.1
8750 -3.9 25.0 055 15 8 3.4 1.9 | -4.4 24.1 035 14 7 4.0 2.2
8500 -3.6 25.5 045 15 8 4.6 2.5 | -4.1 24.6 035 15 8 4.7 2.6
8250 -3.3 26.1 035 16 8 3.9 2.1 | -3.8 25.2 040 16 8 4.4 2.4
8000 -3.0 26.6 030 16 8 3.5 1.9 | -3.5 25.7 040 17 9 4.1 2.2
7750 -2.7 27.1 025 17 9 3.7 2.0 | -3.2 26.2 045 17 9 4.3 2.4
7500 -2.5 27.5 020 16 8 3.1 1.7 | -2.9 26.8 040 18 9 4.3 2.4
7250 -2.3 27.9 020 16 8 2.1 1.2 | -2.6 27.3 040 18 9 3.7 2.0
7000 -2.2 28.0 015 16 8 1.0 0.6 | -2.3 27.9 040 18 9 2.7 1.5
6750 -2.1 28.2 015 16 8 3.6 2.0 | -2.1 28.2 035 19 10 5.3 2.9
6500 -1.7 28.9 010 13 7 5.0 2.8 | -1.6 29.1 030 18 9 5.8 3.2
6250 -1.4 29.5 005 11 6 3.9 2.1 | -1.3 29.7 025 16 8 3.9 2.1
6000 -1.1 30.0 360 9 5 3.3 1.8 | -1.0 30.2 015 14 7 4.0 2.2
5750 -0.8 30.6 350 8 4 6.8 3.7 | -0.7 30.7 010 13 7 5.5 3.0
5500 -0.0 32.0 345 6 3 14.8 8.1 | -0.2 31.6 360 10 5 9.1 5.0
________________________________________________________________________________
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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