Soaring Guidance
Issued by NWS Grand Junction, CO
Issued by NWS Grand Junction, CO
911
UXUS97 KGJT 081306
SRGGJT
Soaring Forecast
National Weather Service Grand Junction, Colorado
606 AM MST Friday, November 8, 2024
This forecast is for Friday, November 8, 2024:
If the trigger temperature of 43.5 F/6.4 C is reached...then
Thermal Soaring Index....................... Poor
Maximum rate of lift........................ 0 ft/min (0.0 m/s)
Maximum height of thermals.................. 9303 ft MSL (4464 ft AGL)
Forecast maximum temperature................... 47.0 F/8.8 C
Time of trigger temperature.................... 1145 MST
Time of overdevelopment........................ 1300 MST
Middle/high clouds during soaring window....... Broken/overcast opaque middle
Surface winds during soaring window............ 20 mph or less
Height of the -3 thermal index................. 7370 ft MSL (2531 ft AGL)
Thermal soaring outlook for Saturday 11/09..... Poor
Wave Soaring Index............................. Not available
Remarks...
Sunrise/Sunset.................... 06:50:24 / 17:05:23 MST
Total possible sunshine........... 10 hr 14 min 59 sec (614 min 59 sec)
Altitude of sun at 11:57:53 MST... 34.01 degrees
Upper air data from rawinsonde observation taken on 11/08/2024 at 0500 MST
Freezing level.................. 6477 ft MSL (1638 ft AGL)
Convective condensation level... 15254 ft MSL (10415 ft AGL)
Lifted condensation level....... 11765 ft MSL (6926 ft AGL)
Lifted index.................... +11.0
K index......................... +13.9
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 -72.6 330 13 7 5.2 2.8 102.4 216.3 53.8 M M
45000 -57.3 -71.1 015 57 29 7.6 4.2 79.1 174.4 43.4 M M
40000 -46.7 -52.1 020 57 29 4.7 2.6 72.7 162.9 42.2 M M
38000 -44.2 -47.6 015 64 33 6.3 3.5 66.6 151.8 39.3 M M
36000 -40.4 -40.7 015 60 31 6.3 3.4 63.5 146.3 38.1 M M
34000 -36.9 -34.4 015 59 30 1.1 0.6 60.1 140.2 36.7 M M
32000 -37.9 -36.2 030 52 27 -0.2 -0.1 50.7 123.2 30.7 M M
30000 -36.8 -34.2 015 44 23 0.7 0.4 44.2 111.5 26.7 M M
29000 -37.9 -36.2 025 56 29 -4.9 -2.7 38.7 101.7 22.9 M M
28000 -39.4 -38.9 020 66 34 -5.5 -3.0 32.9 91.3 18.8 M M
27000 -38.6 -37.5 020 64 33 7.8 4.3 30.1 86.1 16.8 M M
26000 -36.1 -33.0 020 58 30 8.4 4.6 29.6 85.2 16.6 M M
25000 -33.7 -28.7 025 63 32 8.0 4.4 28.9 84.1 16.3 M M
24000 -31.3 -24.3 025 57 29 7.9 4.3 28.3 82.9 15.9 M M
23000 -28.8 -19.8 020 49 25 7.2 4.0 27.7 81.9 15.7 M M
22000 -26.7 -16.1 020 45 23 6.9 3.8 26.8 80.3 15.1 M M
21000 -24.9 -12.8 020 35 18 4.9 2.7 25.4 77.8 14.1 M M
20000 -22.4 -8.3 020 34 17 6.8 3.7 24.1 75.4 13.1 M M
19500 -21.2 -6.2 025 35 18 8.1 4.5 23.7 74.7 12.9 M M
19000 -20.0 -4.0 025 38 20 8.0 4.4 23.4 74.1 12.7 M M
18500 -18.8 -1.8 025 38 20 7.3 4.0 23.1 73.6 12.5 M M
18000 -18.3 -0.9 025 37 19 1.4 0.8 22.0 71.6 11.6 M M
17500 -17.9 -0.2 030 30 16 2.3 1.3 20.8 69.4 10.6 M M
17000 -17.3 0.9 035 25 13 7.3 4.0 19.9 67.8 9.9 M M
16500 -16.2 2.8 035 25 13 7.4 4.1 19.5 67.0 9.5 M M
16000 -15.2 4.6 050 22 11 6.0 3.3 18.9 66.1 9.1 M M
15500 -14.3 6.3 050 23 12 6.2 3.4 18.3 65.0 8.6 M M
15000 -13.4 7.9 050 15 8 6.1 3.4 17.7 63.9 8.1 M M
14500 -12.5 9.5 055 16 8 5.9 3.2 17.1 62.8 7.6 M M
14000 -11.6 11.1 050 11 6 5.9 3.2 16.5 61.6 7.0 M M
13500 -10.8 12.6 045 8 4 5.9 3.2 15.8 60.5 6.4 M M
13000 -9.9 14.2 035 6 3 6.0 3.3 15.2 59.3 5.9 M M
12500 -9.1 15.6 070 3 2 5.3 2.9 14.5 58.1 5.3 M M
12000 -8.3 17.1 130 4 2 5.4 3.0 13.8 56.9 4.7 M M
11500 -7.5 18.5 100 5 3 5.4 3.0 13.1 55.6 4.0 M M
11000 -6.7 19.9 090 7 4 5.5 3.0 12.4 54.3 3.4 M M
10500 -5.9 21.4 085 13 7 4.7 2.6 11.7 53.0 2.7 M M
10250 -5.6 21.9 080 16 8 4.7 2.6 11.3 52.3 2.3 M M
10000 -5.2 22.6 075 16 8 5.0 2.7 10.9 51.6 1.9 M M
9750 -4.9 23.2 070 11 6 3.7 2.0 10.5 50.8 1.5 M M
9500 -4.8 23.4 075 8 4 -1.9 -1.0 9.8 49.6 0.9 M M
9250 -5.1 22.8 060 5 3 -4.4 -2.4 8.7 47.7 -0.1 264 1.3
9000 -5.3 22.5 065 5 2 -4.7 -2.6 7.6 45.7 -1.1 265 1.3
8750 -5.6 21.9 060 5 3 -0.7 -0.4 6.6 43.8 -2.1 265 1.3
8500 -5.3 22.5 055 6 3 7.2 4.0 6.1 43.0 -2.5 249 1.3
8250 -4.7 23.5 045 8 4 8.7 4.8 6.0 42.8 -2.6 222 1.1
8000 -4.0 24.8 065 7 4 8.3 4.6 5.9 42.6 -2.7 196 1.0
7750 -3.4 25.9 060 8 4 8.4 4.6 5.8 42.5 -2.8 170 0.9
7500 -2.8 27.0 055 10 5 8.4 4.6 5.7 42.3 -2.9 143 0.7
7250 -2.1 28.2 050 9 5 8.4 4.6 5.6 42.1 -3.0 117 0.6
7000 -1.5 29.3 040 8 4 8.4 4.6 5.5 41.9 -3.1 90 0.5
6750 -0.9 30.4 040 8 4 8.4 4.6 5.4 41.7 -3.2 64 0.3
6500 -0.2 31.6 045 7 4 8.3 4.6 5.3 41.5 -3.4 37 0.2
6250 0.4 32.7 050 6 3 8.7 4.8 5.2 41.3 -3.5 11 0.1
6000 1.0 33.8 085 6 3 7.4 4.1 5.1 41.2 -3.6 M M
5750 1.5 34.7 105 7 4 5.6 3.1 4.8 40.7 -3.9 M M
5500 1.9 35.4 120 9 5 5.7 3.1 4.5 40.1 -4.2 M M
5250 2.2 36.0 145 9 5 1.8 1.0 4.1 39.4 -4.7 M M
5000 2.0 35.6 140 10 5 -4.0 -2.2 3.3 37.9 -5.5 M M
* * * * * * Numerical weather prediction model forecast data valid * * * * * *
11/08/2024 at 0800 MST | 11/08/2024 at 1100 MST
|
CAPE... 0.0 LI... +4.7 | CAPE... 0.0 LI... +6.7
CINH... -0.1 K Index... +15.1 | CINH... -0.1 K Index... +1.0
|
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 -59.7 -75.5 005 17 9 2.8 1.5 | -60.6 -77.1 325 13 7 2.8 1.5
45000 -55.0 -67.0 015 34 17 5.7 3.1 | -55.7 -68.3 350 25 13 6.3 3.4
40000 -46.0 -50.8 360 44 23 5.7 3.1 | -45.8 -50.4 350 37 19 6.3 3.5
38000 -42.3 -44.1 005 46 24 6.3 3.4 | -41.9 -43.4 355 38 19 6.5 3.5
36000 -38.5 -37.3 005 48 25 6.3 3.4 | -38.0 -36.4 360 38 19 6.5 3.5
34000 -35.8 -32.4 010 46 24 -0.3 -0.2 | -35.5 -31.9 005 35 18 -1.3 -0.7
32000 -36.2 -33.2 020 37 19 -0.5 -0.3 | -36.4 -33.5 025 26 13 -1.5 -0.8
30000 -36.4 -33.5 035 30 15 0.5 0.3 | -37.2 -35.0 060 22 11 -0.4 -0.2
29000 -36.3 -33.3 045 27 14 0.4 0.2 | -37.3 -35.1 085 26 13 -0.4 -0.2
28000 -36.1 -33.0 055 25 13 0.4 0.2 | -37.4 -35.3 100 33 17 -0.4 -0.2
27000 -36.0 -32.8 065 23 12 -0.1 -0.0 | -37.6 -35.7 110 42 22 -0.1 -0.0
26000 -34.9 -30.8 075 23 12 5.0 2.7 | -35.8 -32.4 115 46 24 7.3 4.0
25000 -33.0 -27.4 080 23 12 5.0 2.7 | -33.1 -27.6 115 49 25 7.3 4.0
24000 -31.5 -24.7 085 23 12 5.5 3.0 | -31.0 -23.8 120 52 27 7.4 4.1
23000 -29.5 -21.1 085 23 12 7.0 3.8 | -28.7 -19.7 115 49 25 7.6 4.2
22000 -27.4 -17.3 080 22 11 7.0 3.8 | -26.4 -15.5 115 45 23 7.6 4.2
21000 -25.3 -13.5 075 22 11 7.2 3.9 | -24.2 -11.6 115 41 21 7.4 4.1
20000 -23.2 -9.8 065 22 11 7.2 4.0 | -22.0 -7.6 115 38 20 7.4 4.1
19500 -22.1 -7.8 060 22 11 7.2 4.0 | -20.9 -5.6 120 37 19 7.4 4.1
19000 -21.0 -5.8 055 23 12 7.2 3.9 | -19.7 -3.5 120 36 18 7.4 4.1
18500 -20.0 -4.0 050 23 12 6.5 3.6 | -18.7 -1.7 120 34 18 6.7 3.7
18000 -19.1 -2.4 050 24 12 6.0 3.3 | -17.7 0.1 125 32 16 6.4 3.5
17500 -18.2 -0.8 045 25 13 6.0 3.3 | -16.7 1.9 125 29 15 6.3 3.5
17000 -17.5 0.5 045 24 13 4.0 2.2 | -15.8 3.6 125 26 13 6.0 3.3
16500 -16.9 1.6 045 24 12 4.1 2.2 | -14.9 5.2 120 22 11 6.0 3.3
16000 -16.2 2.8 045 23 12 5.6 3.1 | -13.9 7.0 110 19 10 6.5 3.6
15500 -15.4 4.3 045 21 11 5.8 3.2 | -13.0 8.6 105 18 9 6.6 3.6
15000 -14.5 5.9 050 19 10 5.8 3.2 | -12.0 10.4 095 18 9 5.3 2.9
14500 -13.7 7.3 050 17 9 5.7 3.1 | -11.3 11.7 090 18 9 4.6 2.5
14000 -12.9 8.8 055 16 8 5.9 3.2 | -10.6 12.9 090 19 10 3.9 2.1
13500 -12.0 10.4 060 14 7 6.2 3.4 | -10.2 13.6 085 18 9 2.9 1.6
13000 -11.1 12.0 065 12 6 6.1 3.3 | -9.8 14.4 085 18 9 3.3 1.8
12500 -10.2 13.6 065 11 6 5.8 3.2 | -9.3 15.3 080 16 8 4.4 2.4
12000 -9.3 15.3 070 10 5 5.6 3.1 | -8.7 16.3 080 14 7 4.6 2.5
11500 -8.6 16.5 075 10 5 4.8 2.6 | -7.9 17.8 085 13 7 5.3 2.9
11000 -7.9 17.8 080 9 5 4.6 2.5 | -7.2 19.0 085 11 6 5.3 2.9
10500 -7.3 18.9 080 9 5 4.2 2.3 | -6.4 20.5 090 10 5 5.3 2.9
10250 -7.0 19.4 080 9 4 3.7 2.0 | -6.0 21.2 090 9 5 5.5 3.0
10000 -6.7 19.9 080 8 4 5.5 3.0 | -5.6 21.9 090 8 4 4.9 2.7
9750 -6.2 20.8 085 8 4 5.5 3.0 | -5.2 22.6 090 8 4 4.9 2.7
9500 -5.9 21.4 080 8 4 3.6 2.0 | -4.9 23.2 090 7 4 5.5 3.0
9250 -5.6 21.9 075 8 4 4.2 2.3 | -4.5 23.9 090 7 3 5.5 3.0
9000 -5.2 22.6 070 7 4 6.5 3.6 | -4.0 24.8 090 6 3 6.5 3.5
8750 -4.3 24.3 065 7 4 4.4 2.4 | -3.2 26.2 085 5 3 3.9 2.2
8500 -3.9 25.0 060 7 4 5.1 2.8 | -2.9 26.8 080 4 2 4.7 2.6
8250 -3.5 25.7 060 7 3 4.8 2.6 | -2.6 27.3 075 4 2 4.8 2.6
8000 -3.2 26.2 055 6 3 5.8 3.2 | -2.2 28.0 075 3 2 6.9 3.8
7750 -2.7 27.1 055 6 3 6.6 3.6 | -1.5 29.3 065 3 2 8.7 4.8
7500 -2.2 28.0 050 6 3 5.5 3.0 | -1.0 30.2 060 3 2 5.8 3.2
7250 -1.8 28.8 050 6 3 4.3 2.3 | -0.7 30.7 055 2 1 2.6 1.4
7000 -1.5 29.3 050 6 3 6.6 3.6 | -0.4 31.3 050 2 1 7.9 4.3
6750 -0.9 30.4 045 6 3 7.1 3.9 | 0.5 32.9 045 2 1 11.1 6.1
6500 -0.5 31.1 045 5 3 5.1 2.8 | 1.1 34.0 040 1 1 8.7 4.8
6250 -0.1 31.8 050 4 2 5.4 3.0 | 1.8 35.2 040 1 0 8.4 4.6
6000 0.3 32.5 050 4 2 5.2 2.9 | 2.5 36.5 000 0 0 10.7 5.9
5750 0.7 33.3 060 2 1 4.8 2.6 | 3.5 38.3 035 1 0 18.4 10.1
5500 1.0 33.8 090 1 1 2.5 1.4 | 4.9 40.8 000 0 0 15.5 8.5
5250 M M M M M M M | M M M M M M M
5000 M M M M M M M | M M M M M M M
11/08/2024 at 1400 MST | 11/08/2024 at 1700 MST
|
CAPE... 0.0 LI... +5.5 | CAPE... 0.0 LI... +5.5
CINH... 0.0 K Index... +12.2 | CINH... -0.1 K Index... +14.5
|
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 -61.3 -78.3 300 14 7 2.9 1.6 | -61.5 -78.7 280 17 9 2.9 1.6
45000 -56.3 -69.3 325 24 12 6.5 3.6 | -56.4 -69.5 310 23 12 6.7 3.7
40000 -45.9 -50.6 330 33 17 6.6 3.6 | -45.7 -50.3 325 32 16 6.9 3.8
38000 -42.1 -43.8 340 32 16 6.4 3.5 | -42.1 -43.8 330 30 15 5.8 3.2
36000 -38.3 -36.9 345 30 16 6.4 3.5 | -38.7 -37.7 335 28 14 5.8 3.2
34000 -36.0 -32.8 360 26 14 -1.8 -1.0 | -36.9 -34.4 355 20 10 -3.2 -1.7
32000 -37.1 -34.8 050 24 13 -1.9 -1.1 | -38.9 -38.0 075 28 14 -3.3 -1.8
30000 -37.8 -36.0 080 34 18 2.0 1.1 | -39.6 -39.3 095 51 26 5.5 3.0
29000 -37.3 -35.1 085 37 19 1.9 1.0 | -38.0 -36.4 095 55 28 5.6 3.1
28000 -36.7 -34.1 090 41 21 1.9 1.1 | -36.3 -33.3 095 59 31 5.6 3.1
27000 -36.1 -33.0 095 44 23 2.7 1.5 | -34.6 -30.3 100 64 33 5.8 3.2
26000 -34.3 -29.7 095 41 21 6.7 3.7 | -32.7 -26.9 100 56 29 6.3 3.4
25000 -31.9 -25.4 090 35 18 6.7 3.7 | -30.9 -23.6 100 48 25 6.3 3.4
24000 -29.9 -21.8 085 30 15 7.1 3.9 | -28.5 -19.3 100 38 20 7.0 3.9
23000 -27.6 -17.7 085 27 14 7.6 4.2 | -26.2 -15.2 090 32 17 7.6 4.2
22000 -25.3 -13.5 085 25 13 7.6 4.2 | -23.9 -11.0 075 28 15 7.7 4.2
21000 -23.1 -9.6 085 22 12 6.6 3.6 | -21.7 -7.1 060 26 13 6.7 3.7
20000 -21.2 -6.2 085 23 12 6.5 3.6 | -19.8 -3.6 055 25 13 6.7 3.7
19500 -20.2 -4.4 085 24 12 6.5 3.6 | -18.8 -1.8 055 25 13 6.7 3.7
19000 -19.3 -2.7 080 24 12 6.6 3.6 | -17.8 -0.0 050 24 12 6.8 3.7
18500 -18.3 -0.9 080 24 13 6.4 3.5 | -16.8 1.8 050 24 12 5.9 3.2
18000 -17.4 0.7 075 25 13 6.3 3.5 | -16.0 3.2 050 24 12 5.6 3.1
17500 -16.4 2.5 070 25 13 6.3 3.4 | -15.2 4.6 045 24 12 5.5 3.0
17000 -15.6 3.9 065 26 13 5.9 3.2 | -14.5 5.9 050 23 12 5.3 2.9
16500 -14.7 5.5 060 26 13 5.9 3.2 | -13.7 7.3 050 23 12 5.2 2.9
16000 -13.8 7.2 055 26 13 6.3 3.5 | -12.9 8.8 050 23 12 6.2 3.4
15500 -12.8 9.0 055 24 13 6.4 3.5 | -11.9 10.6 050 23 12 6.2 3.4
15000 -11.9 10.6 050 23 12 6.4 3.5 | -11.0 12.2 050 23 12 5.7 3.1
14500 -10.9 12.4 050 22 12 6.3 3.5 | -10.3 13.5 050 23 12 5.3 2.9
14000 -10.0 14.0 045 22 11 6.2 3.4 | -9.5 14.9 045 24 12 5.1 2.8
13500 -9.1 15.6 045 22 11 5.9 3.3 | -8.8 16.2 045 24 12 4.6 2.5
13000 -8.2 17.2 045 22 11 6.0 3.3 | -8.1 17.4 040 24 12 4.5 2.5
12500 -7.3 18.9 045 21 11 6.3 3.5 | -7.6 18.3 040 23 12 3.7 2.0
12000 -6.3 20.7 050 20 10 5.9 3.3 | -7.0 19.4 035 21 11 3.6 2.0
11500 -5.6 21.9 050 18 9 4.5 2.5 | -6.6 20.1 030 19 10 2.6 1.4
11000 -4.9 23.2 050 16 8 4.4 2.4 | -6.2 20.8 025 17 9 2.9 1.6
10500 -4.3 24.3 045 14 7 3.7 2.0 | -5.6 21.9 015 15 8 4.0 2.2
10250 -4.1 24.6 040 12 6 3.9 2.1 | -5.4 22.3 010 14 7 3.2 1.8
10000 -3.8 25.2 035 11 6 3.4 1.9 | -5.1 22.8 005 14 7 5.9 3.2
9750 -3.6 25.5 030 9 5 3.8 2.1 | -4.5 23.9 005 12 6 8.0 4.4
9500 -3.2 26.2 025 8 4 4.7 2.6 | -3.9 25.0 360 12 6 7.1 3.9
9250 -2.9 26.8 020 7 4 4.2 2.3 | -3.4 25.9 360 11 6 7.1 3.9
9000 -2.6 27.3 010 7 3 5.7 3.1 | -2.8 27.0 355 10 5 8.7 4.8
8750 -1.6 29.1 355 6 3 6.5 3.6 | -1.5 29.3 350 10 5 7.9 4.3
8500 -1.1 30.0 350 5 3 6.5 3.5 | -0.9 30.4 350 9 5 8.1 4.5
8250 -0.7 30.7 345 5 3 5.8 3.2 | -0.3 31.5 345 9 5 7.8 4.3
8000 -0.2 31.6 335 5 3 7.4 4.1 | 0.3 32.5 340 9 5 8.2 4.5
7750 0.5 32.9 335 5 3 9.3 5.1 | 0.9 33.6 335 8 4 8.8 4.8
7500 1.1 34.0 330 5 2 7.7 4.2 | 1.6 34.9 335 8 4 7.9 4.3
7250 1.6 34.9 320 5 2 5.7 3.1 | 2.1 35.8 330 8 4 6.8 3.7
7000 2.1 35.8 310 5 2 8.6 4.7 | 2.7 36.9 320 8 4 8.1 4.4
6750 2.8 37.0 310 4 2 10.9 6.0 | 3.3 37.9 320 7 3 9.2 5.0
6500 3.6 38.5 305 4 2 10.0 5.5 | 4.0 39.2 315 6 3 8.7 4.8
6250 4.4 39.9 300 4 2 10.3 5.7 | 4.7 40.5 310 6 3 9.4 5.1
6000 5.1 41.2 295 4 2 9.6 5.3 | 5.3 41.5 305 6 3 7.0 3.8
5750 5.9 42.6 300 4 2 12.3 6.7 | 5.6 42.1 305 4 2 0.5 0.3
5500 7.5 45.5 290 4 2 35.8 19.7 | 5.7 42.3 300 4 2 7.6 4.2
5250 M M M M M M M | M M M M M M M
5000 M M M M M M M | M M M M M M M
________________________________________________________________________________
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 at Walker Field in Grand
Junction, Colorado at
North Latitude: 39 deg 07 min 00.001 sec
West Longitude: 108 deg 31 min 59.998 sec
Elevation: 4839 feet (1475 meters)
and may not be representative of other areas along the Western Slope of
Colorado. 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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