National Weather Service Text Product
AFOS product SRGPUB
Dates interpreted at 00:00 UTCDisplaying AFOS PIL: SRGPUB
Product Timestamp: 2020-12-15 13:50 UTC
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468
UXUS97 KPUB 151350
SRGPUB
Soaring Forecast
National Weather Service Pueblo, Colorado
0650 MST Tuesday, December 15, 2020
This forecast is for the Air Force Academy for Tuesday, December 15, 2020:
If the trigger temperature of 25.2 F/-3.8 C is reached...then
Thermal Soaring Index....................... Poor
Maximum rate of lift........................ 0 ft/min (0.0 m/s)
Maximum height of thermals.................. 12046 ft MSL (4428 ft AGL)
Forecast maximum temperature................... 27.0 F/-3.2 C
Time of trigger temperature.................... 1145 MST
Time of overdevelopment........................ None
Middle/high clouds during soaring window....... Broken/overcast opaque middle
Surface winds during soaring window............ Between 20 mph and 30 mph
Height of the -3 thermal index................. 10517 ft MSL (2899 ft AGL)
Thermal soaring outlook for Wednesday 12/16.... Poor
Wave Soaring Index............................. Not available
Remarks...
Sunrise/Sunset.................... 07:11:28 / 16:38:07 MST
Total possible sunshine........... 9 hr 26 min 39 sec (566 min 39 sec)
Altitude of sun at 11:54:47 MST... 27.69 degrees
Upper air data from numerical model forecast valid on 12/15/2020 at 0500 MST
Freezing level.................. Entire airmass below 32 F / 0 C
Convective condensation level... 14322 ft MSL (6704 ft AGL)
Lifted condensation level....... 12660 ft MSL (5043 ft AGL)
Lifted index.................... +7.3
K index......................... +6.1
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 -56.0 -68.8 280 20 10 2.2 1.2 M M M M M
45000 -52.5 -62.5 275 15 8 2.2 1.2 M M M M M
40000 -49.1 -56.4 280 15 8 2.3 1.2 M M M M M
38000 -47.8 -54.0 285 15 8 1.0 0.5 M M M M M
36000 -47.5 -53.5 290 11 6 0.6 0.3 M M M M M
34000 -47.1 -52.8 295 8 4 0.5 0.3 M M M M M
32000 -48.0 -54.4 305 6 3 -2.3 -1.3 M M M M M
30000 -49.4 -56.9 315 4 2 -2.2 -1.2 M M M M M
29000 -49.3 -56.7 315 2 1 4.0 2.2 17.2 63.0 15.4 M M
28000 -48.1 -54.6 285 1 0 3.9 2.2 14.8 58.7 13.8 M M
27000 -47.0 -52.6 165 1 1 3.9 2.2 12.6 54.7 12.2 M M
26000 -45.8 -50.4 155 3 2 6.1 3.4 10.6 51.2 10.7 M M
25000 -43.5 -46.3 160 2 1 7.6 4.1 9.7 49.5 10.1 M M
24000 -41.2 -42.2 165 2 1 7.6 4.1 8.9 48.0 9.6 M M
23000 -39.0 -38.2 175 1 1 8.1 4.5 8.2 46.8 9.1 M M
22000 -36.4 -33.5 000 0 0 8.5 4.7 7.7 45.9 8.8 M M
21000 -33.2 -27.8 330 2 1 8.5 4.7 7.2 45.0 8.5 M M
20000 -30.9 -23.6 340 4 2 7.5 4.1 6.6 43.9 8.1 M M
19500 -29.7 -21.5 345 4 2 7.5 4.1 6.2 43.1 7.7 M M
19000 -28.6 -19.5 345 5 3 7.5 4.1 5.8 42.5 7.4 M M
18500 -27.5 -17.5 350 6 3 7.5 4.1 5.5 41.8 7.2 M M
18000 -26.4 -15.5 350 6 3 7.9 4.3 5.1 41.3 6.9 M M
17500 -25.2 -13.4 350 6 3 8.1 4.4 4.8 40.7 6.7 M M
17000 -24.0 -11.2 350 5 3 8.1 4.4 4.6 40.2 6.5 M M
16500 -22.8 -9.0 350 5 3 7.7 4.2 4.3 39.7 6.2 M M
16000 -21.7 -7.1 345 6 3 7.9 4.3 3.9 39.1 5.9 M M
15500 -20.6 -5.1 345 6 3 6.1 3.4 3.5 38.3 5.6 M M
15000 -19.7 -3.5 345 7 4 6.2 3.4 2.9 37.2 5.1 M M
14500 -18.8 -1.8 345 9 4 5.0 2.7 2.3 36.1 4.5 M M
14000 -18.1 -0.6 345 10 5 4.7 2.6 1.4 34.6 3.7 M M
13500 -17.5 0.5 345 12 6 3.7 2.0 0.6 33.1 3.0 M M
13000 -17.0 1.4 345 14 7 3.1 1.7 -0.5 31.2 2.0 M M
12500 -16.5 2.3 345 16 8 3.5 1.9 -1.5 29.4 1.0 M M
12000 -16.1 3.0 350 18 9 2.2 1.2 -2.6 27.3 -0.0 370 1.9
11750 -15.9 3.4 350 19 10 2.2 1.2 -3.2 26.3 -0.6 358 1.8
11500 -15.7 3.7 350 20 10 3.7 2.0 -3.7 25.3 -1.1 345 1.8
11250 -15.4 4.3 350 21 11 4.3 2.3 -4.1 24.5 -1.5 328 1.7
11000 -15.2 4.6 350 21 11 3.5 1.9 -4.6 23.7 -2.0 312 1.6
10750 -14.9 5.2 350 22 11 3.8 2.1 -5.1 22.8 -2.5 297 1.5
10500 -14.6 5.7 350 22 11 3.9 2.1 -5.6 22.0 -2.9 281 1.4
10250 -14.3 6.3 350 23 12 4.2 2.3 -6.0 21.2 -3.4 265 1.3
10000 -14.0 6.8 350 23 12 4.7 2.6 -6.4 20.5 -3.8 248 1.3
9750 -13.6 7.5 350 23 12 4.8 2.6 -6.8 19.8 -4.2 230 1.2
9500 -13.3 8.1 350 23 12 4.6 2.5 -7.2 19.1 -4.6 212 1.1
9250 -13.0 8.6 350 23 12 4.6 2.5 -7.6 18.4 -5.0 195 1.0
9000 -12.6 9.3 350 22 12 7.7 4.2 -7.9 17.8 -5.3 175 0.9
8750 -11.9 10.6 350 22 11 7.2 4.0 -8.0 17.6 -5.4 149 0.8
8500 -11.5 11.3 350 20 10 4.7 2.6 -8.3 17.0 -5.8 130 0.7
8250 -11.2 11.8 350 18 9 5.2 2.9 -8.7 16.4 -6.2 111 0.6
8000 -10.8 12.6 350 16 8 6.2 3.4 -9.0 15.8 -6.5 92 0.5
7750 -10.2 13.6 350 12 6 8.4 4.6 -9.2 15.5 -6.7 68 0.3
7500 M M M M M M M M M M M M
7250 M M M M M M M M M M M M
7000 M M M M M M M M M M M M
6750 M M M M M M M M M M M M
* * * * * * Numerical weather prediction model forecast data valid * * * * * *
12/15/2020 at 0800 MST | 12/15/2020 at 1100 MST
|
CAPE... +0.3 LI... +4.3 | CAPE... +19.9 LI... +5.8
CINH... -0.1 K Index... +3.4 | CINH... 0.0 K Index... -0.3
|
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 -56.4 -69.5 285 19 10 1.8 1.0 | -56.8 -70.2 285 19 10 1.8 1.0
45000 -53.6 -64.5 285 17 9 1.8 1.0 | -53.9 -65.0 300 19 10 1.9 1.0
40000 -49.4 -56.9 300 18 9 3.0 1.6 | -50.3 -58.5 315 18 9 2.4 1.3
38000 -47.7 -53.9 305 18 9 1.2 0.6 | -48.9 -56.0 320 18 9 0.9 0.5
36000 -47.2 -53.0 315 14 7 0.8 0.4 | -48.5 -55.3 330 16 8 0.7 0.4
34000 -46.6 -51.9 325 10 5 0.7 0.4 | -48.0 -54.4 345 16 8 0.6 0.4
32000 -47.9 -54.2 340 9 4 -3.4 -1.8 | -48.7 -55.7 355 15 8 -1.9 -1.0
30000 -49.9 -57.8 355 8 4 -3.2 -1.8 | -49.9 -57.8 360 15 8 -1.7 -0.9
29000 -50.0 -58.0 355 8 4 3.8 2.1 | -49.5 -57.1 360 15 8 3.7 2.1
28000 -48.9 -56.0 355 7 4 3.8 2.1 | -48.4 -55.1 360 14 7 3.9 2.2
27000 -47.8 -54.0 350 6 3 3.8 2.1 | -47.2 -53.0 360 13 7 3.9 2.2
26000 -46.6 -51.9 345 6 3 6.8 3.7 | -45.8 -50.4 360 13 7 7.6 4.1
25000 -44.1 -47.4 345 6 3 8.3 4.6 | -43.3 -45.9 005 12 6 8.3 4.6
24000 -41.6 -42.9 345 7 3 8.3 4.6 | -40.9 -41.6 005 12 6 8.3 4.6
23000 -39.1 -38.4 350 7 4 8.8 4.8 | -38.4 -37.1 005 11 6 8.7 4.8
22000 -36.4 -33.5 355 8 4 9.0 5.0 | -35.7 -32.3 010 11 6 8.8 4.8
21000 -33.7 -28.7 360 9 4 9.0 5.0 | -32.5 -26.5 015 11 6 8.8 4.8
20000 -30.4 -22.7 005 9 5 8.5 4.7 | -29.8 -21.6 015 11 6 8.9 4.9
19500 -29.2 -20.6 010 9 5 8.5 4.7 | -28.5 -19.3 015 11 6 8.9 4.9
19000 -27.9 -18.2 010 9 4 8.5 4.7 | -27.1 -16.8 015 11 6 8.9 4.9
18500 -26.6 -15.9 010 8 4 8.5 4.7 | -25.8 -14.4 015 11 6 9.0 4.9
18000 -25.4 -13.7 010 8 4 7.8 4.3 | -24.5 -12.1 010 11 6 8.0 4.4
17500 -24.3 -11.7 010 9 5 7.4 4.1 | -23.4 -10.1 010 12 6 7.7 4.2
17000 -23.2 -9.8 005 10 5 7.2 4.0 | -22.2 -8.0 010 13 6 7.1 3.9
16500 -22.2 -8.0 005 12 6 6.4 3.5 | -21.3 -6.3 010 14 7 5.5 3.0
16000 -21.2 -6.2 005 13 7 6.7 3.7 | -20.5 -4.9 010 15 8 5.9 3.2
15500 -20.4 -4.7 005 15 8 4.9 2.7 | -20.0 -4.0 005 16 8 1.8 1.0
15000 -19.6 -3.3 005 16 8 5.2 2.8 | -19.7 -3.5 005 17 9 2.3 1.2
14500 -19.0 -2.2 360 18 9 2.9 1.6 | -19.4 -2.9 360 19 10 1.2 0.6
14000 -18.6 -1.5 360 20 10 2.4 1.3 | -19.2 -2.6 360 20 10 1.0 0.6
13500 -18.3 -0.9 355 21 11 1.8 1.0 | -19.0 -2.2 355 21 11 2.0 1.1
13000 -18.1 -0.6 355 22 11 1.5 0.8 | -18.7 -1.7 355 22 11 2.1 1.2
12500 -17.8 -0.0 355 23 12 2.9 1.6 | -18.2 -0.8 355 22 11 4.1 2.3
12000 -17.5 0.5 355 24 12 1.3 0.7 | -17.8 -0.0 355 22 12 1.8 1.0
11750 -17.4 0.7 355 24 12 1.7 0.9 | -17.7 0.1 355 23 12 2.5 1.4
11500 -17.2 1.0 355 24 12 3.1 1.7 | -17.4 0.7 355 23 12 4.0 2.2
11250 -16.9 1.6 355 24 13 3.9 2.1 | -17.1 1.2 355 23 12 5.0 2.7
11000 -16.6 2.1 355 24 13 3.3 1.8 | -16.7 1.9 355 23 12 4.8 2.7
10750 -16.4 2.5 355 24 13 3.9 2.1 | -16.4 2.5 355 22 12 5.5 3.0
10500 -16.1 3.0 355 24 13 4.9 2.7 | -15.9 3.4 355 22 11 6.4 3.5
10250 -15.7 3.7 355 24 13 5.6 3.1 | -15.4 4.3 355 22 11 6.9 3.8
10000 -15.2 4.6 355 24 12 5.9 3.3 | -14.9 5.2 360 22 11 7.5 4.1
9750 -14.8 5.4 350 24 12 6.6 3.6 | -14.3 6.3 360 21 11 7.6 4.2
9500 -14.3 6.3 350 24 12 7.0 3.9 | -13.8 7.2 355 20 11 7.5 4.1
9250 -13.8 7.2 350 23 12 7.1 3.9 | -13.2 8.2 355 20 10 7.5 4.1
9000 -13.2 8.2 350 23 12 8.9 4.9 | -12.7 9.1 355 19 10 8.6 4.7
8750 -12.5 9.5 350 22 11 8.6 4.7 | -12.0 10.4 355 18 9 10.1 5.6
8500 -12.0 10.4 350 20 10 7.2 3.9 | -11.2 11.8 350 17 9 10.9 6.0
8250 -11.4 11.5 350 19 10 7.4 4.1 | -10.4 13.3 350 16 8 9.3 5.1
8000 -10.8 12.6 345 17 9 8.3 4.6 | -8.4 16.9 345 12 6 22.0 12.1
7750 -10.1 13.8 345 13 7 10.9 6.0 | -7.1 19.2 345 10 5 7.5 4.1
7500 M M M M M M M | M M M M M M M
7250 M M M M M M M | M M M M M M M
7000 M M M M M M M | M M M M M M M
6750 M M M M M M M | M M M M M M M
12/15/2020 at 1400 MST | 12/15/2020 at 1700 MST
|
CAPE... +0.1 LI... +5.0 | CAPE... 0.0 LI... +5.3
CINH... 0.0 K Index... -1.4 | CINH... 0.0 K Index... -10.7
|
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 -57.7 -71.9 290 21 11 2.2 1.2 | -58.8 -73.8 300 22 11 2.2 1.2
45000 -54.5 -66.1 295 20 10 2.2 1.2 | -55.5 -67.9 315 23 12 2.2 1.2
40000 -52.1 -61.8 330 19 10 1.4 0.7 | -54.6 -66.3 330 24 12 0.3 0.2
38000 -51.5 -60.7 340 20 10 -1.2 -0.6 | -54.5 -66.1 335 25 13 -0.2 -0.1
36000 -52.0 -61.6 355 25 13 -0.9 -0.5 | -54.6 -66.3 345 28 14 -0.2 -0.1
34000 -52.6 -62.7 005 30 16 -0.7 -0.4 | -54.7 -66.5 350 31 16 -0.6 -0.4
32000 -50.8 -59.4 010 35 18 4.2 2.3 | -51.7 -61.1 355 33 17 6.0 3.3
30000 -48.3 -54.9 010 40 20 4.2 2.3 | -48.1 -54.6 360 35 18 5.8 3.2
29000 -47.1 -52.8 010 38 19 4.0 2.2 | -46.0 -50.8 360 34 18 7.3 4.0
28000 -45.9 -50.6 010 32 17 4.0 2.2 | -43.8 -46.8 360 34 17 7.3 4.0
27000 -44.7 -48.5 005 27 14 4.0 2.2 | -41.6 -42.9 360 33 17 7.3 4.0
26000 -43.4 -46.1 360 22 12 6.1 3.3 | -39.5 -39.1 360 32 17 6.9 3.8
25000 -40.9 -41.6 360 19 10 6.5 3.6 | -36.9 -34.4 005 30 16 6.9 3.8
24000 -39.0 -38.2 360 16 8 6.5 3.6 | -34.8 -30.6 005 28 15 6.9 3.8
23000 -36.8 -34.2 360 14 7 8.6 4.7 | -32.9 -27.2 005 26 13 5.7 3.1
22000 -34.3 -29.7 360 13 7 8.5 4.7 | -31.2 -24.2 005 23 12 5.6 3.1
21000 -31.7 -25.1 005 13 7 8.5 4.7 | -29.6 -21.3 360 20 10 5.4 3.0
20000 -29.2 -20.6 360 13 7 8.5 4.7 | -27.5 -17.5 360 18 9 7.4 4.1
19500 -27.9 -18.2 360 13 7 8.5 4.7 | -26.4 -15.5 355 18 9 7.4 4.1
19000 -26.6 -15.9 360 13 7 8.5 4.7 | -25.3 -13.5 355 17 9 7.4 4.1
18500 -25.3 -13.5 360 13 7 8.5 4.7 | -24.2 -11.6 355 17 9 7.5 4.1
18000 -24.1 -11.4 355 13 7 7.6 4.2 | -23.1 -9.6 355 17 9 6.3 3.5
17500 -23.0 -9.4 355 14 7 7.3 4.0 | -22.2 -8.0 350 17 9 6.3 3.4
17000 -21.9 -7.4 355 16 8 6.5 3.6 | -21.3 -6.3 350 18 9 6.0 3.3
16500 -21.2 -6.2 355 17 9 4.5 2.5 | -20.4 -4.7 350 18 9 5.7 3.1
16000 -20.5 -4.9 355 18 9 4.6 2.5 | -19.6 -3.3 350 18 9 5.8 3.2
15500 -19.9 -3.8 350 19 10 3.9 2.1 | -18.7 -1.7 350 18 9 6.3 3.4
15000 -19.3 -2.7 350 19 10 4.0 2.2 | -17.8 -0.0 350 18 9 6.5 3.6
14500 -18.8 -1.8 350 20 10 3.7 2.0 | -17.0 1.4 350 18 9 3.7 2.0
14000 -18.2 -0.8 350 20 11 3.6 2.0 | -16.4 2.5 350 18 9 4.0 2.2
13500 -17.7 0.1 350 21 11 4.2 2.3 | -15.8 3.6 350 18 9 2.8 1.5
13000 -17.0 1.4 350 21 11 4.3 2.3 | -15.4 4.3 350 18 9 2.6 1.4
12500 -16.4 2.5 350 21 11 4.3 2.3 | -14.9 5.2 345 18 9 4.3 2.4
12000 -15.8 3.6 350 21 11 3.7 2.0 | -14.4 6.1 345 18 9 3.8 2.1
11750 -15.5 4.1 350 21 11 4.0 2.2 | -14.1 6.6 345 17 9 4.5 2.5
11500 -15.2 4.6 350 21 11 4.7 2.6 | -13.7 7.3 345 17 9 5.6 3.1
11250 -14.8 5.4 350 21 11 6.0 3.3 | -13.3 8.1 345 16 8 6.6 3.6
11000 -14.3 6.3 350 21 11 6.9 3.8 | -12.7 9.1 340 16 8 7.1 3.9
10750 -13.8 7.2 345 20 10 6.3 3.5 | -12.2 10.0 340 15 8 7.1 3.9
10500 -13.4 7.9 345 20 10 5.7 3.1 | -11.7 10.9 335 15 8 7.1 3.9
10250 -13.0 8.6 345 19 10 6.1 3.4 | -11.2 11.8 335 15 7 7.3 4.0
10000 -12.5 9.5 345 18 9 7.4 4.0 | -10.6 12.9 330 14 7 7.7 4.2
9750 -11.9 10.6 345 18 9 6.8 3.7 | -10.0 14.0 330 14 7 6.8 3.7
9500 -11.5 11.3 345 16 8 5.9 3.3 | -9.6 14.7 330 14 7 5.8 3.2
9250 -11.0 12.2 345 15 8 6.3 3.5 | -9.1 15.6 330 13 7 6.4 3.5
9000 -10.5 13.1 345 14 7 8.8 4.8 | -8.7 16.3 330 13 7 7.0 3.8
8750 -9.7 14.5 340 12 6 10.3 5.6 | -8.2 17.2 330 12 6 6.2 3.4
8500 -9.0 15.8 340 11 6 10.2 5.6 | -7.8 18.0 330 11 6 3.5 1.9
8250 -8.3 17.1 340 10 5 8.9 4.9 | -7.4 18.7 325 10 5 9.8 5.4
8000 -7.6 18.3 340 9 5 11.0 6.0 | -6.8 19.8 325 9 5 -2.4 -1.3
7750 -6.5 20.3 340 8 4 19.3 10.6 | -8.4 16.9 320 6 3 -39.3 -21.6
7500 M M M M M M M | M M M M M M M
7250 M M M M M M M | M M M M M M M
7000 M M M M M M M | M M M M M M M
6750 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). 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 Air Force Academy
in Colorado Springs, Colorado at
North Latitude: 38 deg 58 min 48.000 sec
West Longitude: 104 deg 49 min 12.000 sec
Elevation: 6572 feet (2003 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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