Soaring Guidance Issued by NWS Pueblo, CO
000
UXUS97 KPUB 141229
SRGPUB
Soaring Forecast
National Weather Service Pueblo, Colorado
0629 MDT Thursday, March 14, 2024
This forecast is for the Air Force Academy for Thursday, March 14, 2024:
If the trigger temperature of 35.6 F/2.0 C is reached...then
Thermal Soaring Index....................... Poor
Maximum rate of lift........................ 0 ft/min (0.0 m/s)
Maximum height of thermals.................. 7597 ft MSL (0 ft AGL)
Forecast maximum temperature................... 29.0 F/-2.1 C
Time of trigger temperature.................... None
Time of overdevelopment........................ None
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................. None
Thermal soaring outlook for Friday 03/15....... Poor
Wave Soaring Index............................. Not available
Remarks...
Sunrise/Sunset.................... 07:10:46 / 19:05:41 MDT
Total possible sunshine........... 11 hr 54 min 55 sec (714 min 55 sec)
Altitude of sun at 13:08:14 MDT... 48.87 degrees
Upper air data from numerical model forecast valid on 03/14/2024 at 0600 MDT
Freezing level.................. Entire airmass below 32 F / 0 C
Convective condensation level... 10431 ft MSL (2834 ft AGL)
Lifted condensation level....... 9417 ft MSL (1820 ft AGL)
Lifted index.................... +5.5
K index......................... +16.7
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 -53.6 -64.5 255 15 8 1.5 0.8 M M M M M
45000 -51.3 -60.3 230 23 12 1.4 0.8 M M M M M
40000 -51.6 -60.9 230 26 14 -0.4 -0.2 M M M M M
38000 -52.0 -61.6 230 27 14 -2.3 -1.3 M M M M M
36000 -53.2 -63.8 220 28 14 -2.1 -1.2 M M M M M
34000 -54.5 -66.1 210 29 15 -2.0 -1.1 M M M M M
32000 -54.2 -65.6 190 25 13 1.2 0.7 M M M M M
30000 -53.5 -64.3 165 24 12 2.0 1.1 M M M M M
29000 -51.0 -59.8 165 23 12 9.8 5.4 13.5 56.3 11.8 M M
28000 -48.1 -54.6 165 22 11 9.8 5.4 13.5 56.3 11.9 M M
27000 -45.1 -49.2 165 20 11 9.8 5.4 13.6 56.5 12.1 M M
26000 -42.3 -44.1 165 20 10 9.5 5.2 13.6 56.4 12.3 M M
25000 -39.4 -38.9 170 19 10 9.5 5.2 13.4 56.2 12.3 M M
24000 -36.6 -33.9 170 19 10 9.5 5.2 13.4 56.1 12.4 M M
23000 -33.9 -29.0 170 18 9 8.3 4.6 13.2 55.7 12.4 M M
22000 -31.4 -24.5 170 17 9 8.4 4.6 12.6 54.7 12.0 M M
21000 -28.9 -20.0 170 15 8 8.4 4.6 12.2 54.0 11.8 M M
20000 -26.5 -15.7 165 13 7 7.6 4.2 11.6 52.8 11.4 M M
19500 -24.9 -12.8 160 11 5 7.6 4.2 11.0 51.8 10.9 M M
19000 -23.7 -10.7 150 9 5 7.6 4.2 10.6 51.1 10.7 M M
18500 -22.6 -8.7 145 8 4 7.6 4.2 10.3 50.5 10.4 M M
18000 -21.6 -6.9 135 7 4 6.6 3.6 9.9 49.7 10.1 M M
17500 -20.6 -5.1 115 6 3 6.7 3.7 9.3 48.8 9.7 M M
17000 -19.6 -3.3 095 6 3 6.8 3.7 8.9 47.9 9.3 M M
16500 -18.6 -1.5 080 7 4 6.8 3.7 8.4 47.0 8.9 M M
16000 -17.6 0.3 065 9 4 6.7 3.7 7.9 46.2 8.5 M M
15500 -16.6 2.1 065 11 6 6.4 3.5 7.3 45.2 8.0 M M
15000 -15.7 3.7 060 14 7 6.3 3.5 6.8 44.3 7.6 M M
14500 -14.9 5.2 060 17 9 4.0 2.2 6.0 42.9 6.9 M M
14000 -14.3 6.3 065 20 10 4.0 2.2 5.2 41.3 6.1 M M
13500 -13.6 7.5 065 22 11 6.2 3.4 4.4 40.0 5.4 M M
13000 -12.7 9.1 060 23 12 5.5 3.0 3.8 38.9 4.8 M M
12500 -11.6 11.1 060 24 12 8.1 4.4 3.5 38.3 4.5 M M
12000 -10.7 12.7 060 24 13 6.4 3.5 2.9 37.2 4.0 M M
11750 -10.2 13.6 060 25 13 5.8 3.2 2.6 36.8 3.7 M M
11500 -9.8 14.4 055 25 13 6.1 3.3 2.3 36.2 3.4 M M
11250 -9.3 15.3 055 25 13 7.3 4.0 2.1 35.8 3.2 M M
11000 -8.8 16.2 055 25 13 8.0 4.4 1.9 35.5 3.0 M M
10750 -8.2 17.2 055 26 13 7.0 3.8 1.8 35.2 2.9 M M
10500 -7.8 18.0 055 26 14 5.3 2.9 1.5 34.7 2.6 M M
10250 -7.3 18.9 055 27 14 7.5 4.1 1.2 34.1 2.3 M M
10000 -6.7 19.9 055 28 14 10.0 5.5 1.1 34.1 2.2 M M
9750 -6.0 21.2 050 28 15 8.5 4.7 1.1 34.0 2.2 M M
9500 -5.4 22.3 050 28 14 7.7 4.2 1.0 33.7 2.0 M M
9250 -4.9 23.2 050 28 14 7.9 4.3 0.8 33.5 1.9 M M
9000 -4.3 24.3 045 28 14 7.3 4.0 0.7 33.2 1.7 M M
8750 -3.8 25.2 045 26 14 6.6 3.6 0.5 32.8 1.5 M M
8500 -3.4 25.9 040 25 13 6.4 3.5 0.2 32.3 1.2 M M
8250 -2.9 26.8 035 23 12 6.3 3.5 -0.1 31.9 0.9 M M
8000 -2.4 27.7 035 21 11 7.1 3.9 -0.3 31.5 0.7 M M
7750 -1.9 28.6 030 16 8 8.8 4.8 -0.4 31.2 0.5 M M
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 * * * * * *
03/14/2024 at 0900 MDT | 03/14/2024 at 1200 MDT
|
CAPE... +18.1 LI... +0.7 | CAPE... +15.4 LI... +1.7
CINH... 0.0 K Index... +17.9 | CINH... 0.0 K Index... +17.4
|
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 -53.3 -63.9 260 14 7 1.8 1.0 | -54.0 -65.2 260 13 6 2.0 1.1
45000 -50.5 -58.9 240 22 11 1.7 0.9 | -51.1 -60.0 260 17 9 1.9 1.0
40000 -52.0 -61.6 230 30 15 -1.4 -0.7 | -53.0 -63.4 235 29 15 -1.7 -0.9
38000 -52.7 -62.9 230 33 17 -0.3 -0.2 | -53.8 -64.8 230 35 18 0.9 0.5
36000 -53.0 -63.4 220 32 16 -0.4 -0.2 | -53.3 -63.9 225 39 20 0.7 0.4
34000 -53.3 -63.9 215 32 16 -0.5 -0.3 | -52.9 -63.2 220 42 22 0.7 0.4
32000 -53.2 -63.8 185 22 11 0.3 0.1 | -52.4 -62.3 205 29 15 0.9 0.5
30000 -53.0 -63.4 135 24 12 1.1 0.6 | -51.9 -61.4 165 19 10 2.1 1.2
29000 -50.8 -59.4 130 23 12 8.8 4.8 | -49.9 -57.8 145 18 9 7.6 4.2
28000 -48.2 -54.8 130 21 11 8.7 4.8 | -47.6 -53.7 130 19 10 7.6 4.2
27000 -45.6 -50.1 125 20 10 8.7 4.8 | -45.3 -49.5 115 21 11 7.7 4.2
26000 -42.9 -45.2 125 18 9 9.3 5.1 | -42.9 -45.2 110 21 11 8.7 4.8
25000 -40.1 -40.2 125 17 9 9.3 5.1 | -40.3 -40.5 115 19 10 8.7 4.8
24000 -37.4 -35.3 125 15 8 9.3 5.1 | -37.7 -35.9 120 16 8 8.7 4.8
23000 -34.7 -30.5 125 14 7 8.2 4.5 | -35.0 -31.0 125 15 8 8.9 4.9
22000 -32.3 -26.1 120 14 7 8.2 4.5 | -32.4 -26.3 125 15 8 8.9 4.9
21000 -29.8 -21.6 115 14 7 8.2 4.5 | -29.7 -21.5 125 15 8 9.0 4.9
20000 -27.5 -17.5 110 13 7 7.5 4.1 | -26.6 -15.9 125 15 8 8.3 4.5
19500 -25.9 -14.6 105 12 6 7.5 4.1 | -25.4 -13.7 125 15 8 8.3 4.5
19000 -24.7 -12.5 100 12 6 7.5 4.1 | -24.2 -11.6 120 15 8 8.3 4.5
18500 -23.6 -10.5 095 11 6 7.5 4.1 | -22.9 -9.2 120 15 8 8.0 4.4
18000 -22.5 -8.5 095 12 6 7.3 4.0 | -21.8 -7.2 120 15 8 7.1 3.9
17500 -21.5 -6.7 095 12 6 7.3 4.0 | -20.8 -5.4 120 15 8 7.2 4.0
17000 -20.4 -4.7 095 13 7 7.4 4.1 | -19.8 -3.6 115 14 7 6.4 3.5
16500 -19.3 -2.7 095 14 7 7.4 4.1 | -18.8 -1.8 110 13 7 6.5 3.5
16000 -18.2 -0.8 095 15 8 7.4 4.1 | -17.8 -0.0 100 12 6 6.6 3.6
15500 -17.1 1.2 085 16 8 7.4 4.1 | -16.9 1.6 090 13 7 6.8 3.7
15000 -16.0 3.2 080 18 9 7.4 4.0 | -15.9 3.4 085 13 7 6.7 3.7
14500 -14.9 5.2 075 19 10 7.1 3.9 | -14.9 5.2 080 15 8 6.7 3.7
14000 -13.9 7.0 070 20 10 7.1 3.9 | -13.9 7.0 080 16 8 6.6 3.6
13500 -12.9 8.8 065 22 11 6.9 3.8 | -12.9 8.8 075 17 9 6.4 3.5
13000 -11.9 10.6 060 23 12 6.8 3.7 | -12.0 10.4 075 17 9 6.4 3.5
12500 -10.8 12.6 055 24 13 5.8 3.2 | -11.0 12.2 070 17 9 5.8 3.2
12000 -10.3 13.5 055 26 13 3.6 2.0 | -10.3 13.5 060 18 9 4.7 2.6
11750 -10.0 14.0 050 26 14 3.2 1.7 | -10.0 14.0 060 18 9 5.3 2.9
11500 -9.8 14.4 050 27 14 3.2 1.7 | -9.6 14.7 055 19 10 5.6 3.1
11250 -9.5 14.9 050 28 14 3.7 2.1 | -9.2 15.4 050 19 10 4.9 2.7
11000 -9.2 15.4 050 28 14 4.0 2.2 | -8.9 16.0 050 20 10 4.4 2.4
10750 -8.9 16.0 050 28 15 4.1 2.2 | -8.5 16.7 045 21 11 4.0 2.2
10500 -8.7 16.3 050 29 15 3.4 1.9 | -8.3 17.1 040 22 11 3.5 1.9
10250 -8.4 16.9 045 29 15 6.0 3.3 | -8.0 17.6 040 23 12 4.3 2.4
10000 -7.8 18.0 045 29 15 8.6 4.7 | -7.7 18.1 040 24 12 4.9 2.7
9750 -7.2 19.0 045 30 15 6.6 3.6 | -7.3 18.9 035 25 13 4.4 2.4
9500 -6.8 19.8 040 30 15 5.5 3.0 | -7.0 19.4 030 26 13 3.9 2.2
9250 -6.4 20.5 040 30 15 6.8 3.7 | -6.7 19.9 025 27 14 5.3 2.9
9000 -5.8 21.6 035 30 15 8.6 4.7 | -6.2 20.8 020 28 14 7.9 4.3
8750 -5.2 22.6 030 28 15 8.4 4.6 | -5.6 21.9 015 27 14 8.3 4.6
8500 -4.6 23.7 030 27 14 8.4 4.6 | -5.0 23.0 015 25 13 8.2 4.5
8250 -4.0 24.8 025 25 13 7.3 4.0 | -4.4 24.1 010 25 13 7.8 4.3
8000 -3.5 25.7 020 24 12 8.1 4.4 | -3.8 25.2 005 24 12 10.9 6.0
7750 -2.7 27.1 020 19 10 13.2 7.2 | -2.7 27.1 005 19 10 17.6 9.6
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
03/14/2024 at 1500 MDT | 03/14/2024 at 1800 MDT
|
CAPE... +18.3 LI... +0.6 | CAPE... +8.1 LI... +0.8
CINH... 0.0 K Index... +19.0 | CINH... 0.0 K Index... +17.1
|
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 -54.0 -65.2 250 18 9 1.3 0.7 | -54.5 -66.1 260 19 10 1.1 0.6
45000 -52.0 -61.6 245 20 10 1.3 0.7 | -52.8 -63.0 255 24 12 1.1 0.6
40000 -54.0 -65.2 235 35 18 -1.6 -0.9 | -53.9 -65.0 240 36 18 -0.8 -0.5
38000 -54.8 -66.6 235 42 22 0.5 0.3 | -54.4 -65.9 235 43 22 -1.0 -0.5
36000 -54.5 -66.1 230 55 28 0.4 0.2 | -55.0 -67.0 230 61 32 -1.0 -0.5
34000 -54.3 -65.7 230 66 34 0.9 0.5 | -55.6 -68.1 230 78 40 1.6 0.9
32000 -52.0 -61.6 225 58 30 4.1 2.2 | -51.9 -61.4 230 79 40 6.4 3.5
30000 -49.5 -57.1 225 49 25 4.5 2.5 | -48.0 -54.4 235 79 41 6.6 3.6
29000 -48.0 -54.4 215 37 19 5.4 3.0 | -46.0 -50.8 230 69 35 6.7 3.6
28000 -46.3 -51.3 200 25 13 5.4 3.0 | -44.0 -47.2 230 59 30 6.7 3.6
27000 -44.7 -48.5 165 19 10 5.4 3.0 | -42.0 -43.6 230 48 25 6.7 3.7
26000 -42.6 -44.7 145 19 10 8.4 4.6 | -40.1 -40.2 220 35 18 6.2 3.4
25000 -40.1 -40.2 145 19 10 8.5 4.7 | -38.3 -36.9 195 24 12 6.2 3.4
24000 -37.5 -35.5 150 20 10 8.5 4.7 | -36.4 -33.5 150 23 12 6.2 3.4
23000 -34.8 -30.6 150 20 10 9.5 5.2 | -34.2 -29.6 130 27 14 8.5 4.7
22000 -32.0 -25.6 150 21 11 9.6 5.3 | -31.6 -24.9 130 27 14 8.6 4.7
21000 -29.1 -20.4 155 21 11 9.8 5.4 | -28.4 -19.1 130 26 14 8.2 4.5
20000 -26.0 -14.8 145 19 10 8.0 4.4 | -26.1 -15.0 125 26 13 7.7 4.2
19500 -24.8 -12.6 140 18 9 8.0 4.4 | -25.0 -13.0 125 25 13 7.7 4.2
19000 -23.7 -10.7 130 18 9 8.0 4.4 | -23.9 -11.0 125 25 13 7.7 4.2
18500 -22.5 -8.5 125 17 9 7.5 4.1 | -22.7 -8.9 125 24 13 7.6 4.2
18000 -21.5 -6.7 120 16 8 6.5 3.6 | -21.6 -6.9 125 24 12 7.6 4.2
17500 -20.5 -4.9 115 15 8 6.5 3.5 | -20.5 -4.9 125 23 12 7.7 4.2
17000 -19.5 -3.1 115 15 8 7.4 4.1 | -19.4 -2.9 120 23 12 7.0 3.9
16500 -18.4 -1.1 115 15 8 7.4 4.0 | -18.3 -0.9 120 22 11 7.1 3.9
16000 -17.3 0.9 115 16 8 7.8 4.3 | -17.3 0.9 115 22 11 6.8 3.7
15500 -16.1 3.0 110 17 9 8.0 4.4 | -16.3 2.7 115 21 11 6.7 3.7
15000 -14.9 5.2 110 18 9 8.0 4.4 | -15.3 4.5 110 21 11 6.9 3.8
14500 -13.8 7.2 110 19 10 8.0 4.4 | -14.3 6.3 105 22 11 7.0 3.9
14000 -12.6 9.3 105 20 10 7.4 4.1 | -13.2 8.2 100 23 12 7.3 4.0
13500 -11.7 10.9 100 19 10 5.2 2.9 | -12.1 10.2 100 23 12 7.9 4.3
13000 -11.0 12.2 090 18 9 5.2 2.9 | -11.0 12.2 100 24 12 7.7 4.2
12500 -10.3 13.5 085 18 9 4.3 2.3 | -9.9 14.2 095 24 12 5.6 3.1
12000 -9.6 14.7 070 17 9 4.2 2.3 | -9.3 15.3 085 21 11 3.8 2.1
11750 -9.3 15.3 060 17 9 3.7 2.0 | -9.1 15.6 085 20 11 1.9 1.0
11500 -9.1 15.6 060 18 9 3.3 1.8 | -9.0 15.8 080 20 10 1.2 0.7
11250 -8.9 16.0 055 19 10 2.7 1.5 | -8.8 16.2 075 20 10 2.8 1.5
11000 -8.7 16.3 050 20 10 2.3 1.3 | -8.6 16.5 070 20 10 2.8 1.5
10750 -8.5 16.7 045 21 11 2.6 1.4 | -8.5 16.7 065 20 10 1.0 0.6
10500 -8.3 17.1 040 20 11 2.4 1.3 | -8.4 16.9 060 21 11 0.4 0.2
10250 -8.1 17.4 035 21 11 3.2 1.8 | -8.4 16.9 055 22 11 1.2 0.6
10000 -7.8 18.0 035 21 11 4.4 2.4 | -8.2 17.2 050 22 11 2.9 1.6
9750 -7.5 18.5 030 23 12 4.5 2.5 | -7.9 17.8 040 22 11 3.9 2.1
9500 -7.2 19.0 025 24 12 4.0 2.2 | -7.7 18.1 030 21 11 3.7 2.0
9250 -6.9 19.6 020 26 13 5.8 3.2 | -7.4 18.7 020 22 11 4.2 2.3
9000 -6.3 20.7 015 28 14 8.3 4.6 | -7.0 19.4 010 23 12 6.9 3.8
8750 -5.7 21.7 010 27 14 8.2 4.5 | -6.4 20.5 005 22 11 8.4 4.6
8500 -5.1 22.8 010 26 13 8.6 4.7 | -5.8 21.6 360 22 11 8.1 4.4
8250 -4.5 23.9 005 25 13 7.2 4.0 | -5.2 22.6 355 22 11 7.9 4.3
8000 -4.0 24.8 360 25 13 10.8 5.9 | -4.7 23.5 355 21 11 8.7 4.7
7750 -2.8 27.0 360 20 10 20.5 11.3 | -4.0 24.8 350 16 8 10.9 6.0
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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