Soaring Guidance Issued by NWS Pueblo, CO
000
UXUS97 KPUB 241213
SRGPUB
Soaring Forecast
National Weather Service Pueblo, Colorado
0612 MDT Sunday, March 24, 2024
This forecast is for the Air Force Academy for Sunday, March 24, 2024:
If the trigger temperature of 44.0 F/6.7 C is reached...then
Thermal Soaring Index....................... Excellent
Maximum rate of lift........................ 1102 ft/min (5.6 m/s)
Maximum height of thermals.................. 20074 ft MSL (12445 ft AGL)
Forecast maximum temperature................... 54.0 F/12.7 C
Time of trigger temperature.................... 0915 MDT
Time of overdevelopment........................ 1100 MDT
Middle/high clouds during soaring window....... Overcast thin high
Surface winds during soaring window............ 20 mph or less
Height of the -3 thermal index................. 14253 ft MSL (6624 ft AGL)
Thermal soaring outlook for Monday 03/25....... Fair
Wave Soaring Index............................. Not available
Remarks...
Sunrise/Sunset.................... 06:55:02 / 19:15:32 MDT
Total possible sunshine........... 12 hr 20 min 30 sec (740 min 30 sec)
Altitude of sun at 13:05:17 MDT... 52.84 degrees
Upper air data from numerical model forecast valid on 03/24/2024 at 0600 MDT
Freezing level.................. 7750 ft MSL (121 ft AGL)
Additional freezing level....... 9384 ft MSL (1755 ft AGL)
Convective condensation level... 14843 ft MSL (7214 ft AGL)
Lifted condensation level....... 15991 ft MSL (8362 ft AGL)
Lifted index.................... -2.9
K index......................... +8.1
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 -54.8 -66.6 245 45 23 0.9 0.5 M M M M M
45000 -53.4 -64.1 240 58 30 0.9 0.5 M M M M M
40000 -53.7 -64.7 245 67 34 -0.4 -0.2 M M M M M
38000 -54.0 -65.2 245 70 36 -0.9 -0.5 M M M M M
36000 -54.7 -66.5 240 64 33 -1.2 -0.6 M M M M M
34000 -55.4 -67.7 235 59 30 -1.3 -0.7 M M M M M
32000 -53.4 -64.1 230 53 27 4.6 2.5 M M M M M
30000 -50.6 -59.1 225 48 25 4.3 2.3 M M M M M
29000 -48.3 -54.9 225 48 25 8.9 4.9 16.3 61.3 3.1 M M
28000 -45.7 -50.3 220 48 25 8.9 4.9 15.8 60.5 2.8 M M
27000 -43.0 -45.4 220 49 25 8.9 4.9 15.6 60.0 2.7 M M
26000 -40.4 -40.7 220 48 25 8.5 4.7 15.3 59.5 2.5 M M
25000 -37.9 -36.2 220 43 22 8.5 4.7 14.7 58.5 2.0 M M
24000 -35.3 -31.5 220 38 20 8.5 4.7 14.3 57.8 1.7 M M
23000 -32.8 -27.0 225 33 17 8.2 4.5 13.9 57.1 1.4 M M
22000 -30.3 -22.5 225 31 16 8.2 4.5 13.3 56.0 0.9 M M
21000 -27.2 -17.0 225 28 14 8.2 4.5 12.7 54.9 0.4 M M
20000 -24.8 -12.6 225 26 13 8.2 4.5 12.2 53.9 -0.1 1184 6.0
19500 -23.6 -10.5 225 25 13 8.3 4.5 11.9 53.4 -0.4 1132 5.8
19000 -22.3 -8.1 225 24 12 8.3 4.5 11.6 52.9 -0.6 1081 5.5
18500 -21.1 -6.0 225 23 12 8.3 4.5 11.4 52.5 -0.8 1030 5.2
18000 -19.9 -3.8 220 22 11 8.6 4.7 11.2 52.2 -1.0 978 5.0
17500 -18.6 -1.5 220 21 11 8.8 4.8 11.0 51.9 -1.2 924 4.7
17000 -17.3 0.9 215 20 10 8.8 4.8 10.9 51.6 -1.3 870 4.4
16500 -16.0 3.2 210 19 10 8.5 4.7 10.7 51.3 -1.5 817 4.1
16000 -14.7 5.5 210 17 9 8.6 4.7 10.5 50.9 -1.7 764 3.9
15500 -13.5 7.7 210 16 8 7.4 4.1 10.2 50.4 -2.0 713 3.6
15000 -12.5 9.5 210 14 7 7.3 4.0 9.8 49.7 -2.4 666 3.4
14500 -11.4 11.5 210 12 6 7.1 3.9 9.4 49.0 -2.8 619 3.1
14000 -10.3 13.5 230 12 6 7.0 3.8 9.0 48.2 -3.2 574 2.9
13500 -9.3 15.3 250 13 7 6.7 3.7 8.6 47.4 -3.7 528 2.7
13000 -8.4 16.9 255 13 7 5.6 3.1 8.0 46.4 -4.2 487 2.5
12500 -7.3 18.9 270 12 6 9.2 5.1 7.7 45.8 -4.6 439 2.2
12000 -6.2 20.8 280 13 7 7.3 4.0 7.3 45.2 -5.0 390 2.0
11750 -5.6 21.9 280 14 7 7.0 3.9 7.1 44.9 -5.2 366 1.9
11500 -5.1 22.8 285 15 7 9.3 5.1 7.0 44.6 -5.3 342 1.7
11250 -4.3 24.3 280 17 9 8.9 4.9 7.0 44.6 -5.3 312 1.6
11000 -3.8 25.2 285 18 9 6.7 3.7 6.8 44.2 -5.6 289 1.5
10750 -3.3 26.1 290 19 10 7.0 3.9 6.6 43.9 -5.8 266 1.4
10500 -2.8 27.0 290 20 10 7.9 4.3 6.4 43.5 -6.0 244 1.2
10250 -2.2 28.0 295 20 10 8.2 4.5 6.3 43.3 -6.2 218 1.1
10000 -1.6 29.1 295 19 10 7.5 4.1 6.1 43.0 -6.4 194 1.0
9750 -1.1 30.0 300 18 9 7.6 4.2 6.0 42.7 -6.6 170 0.9
9500 -0.5 31.1 300 18 9 8.2 4.5 5.8 42.5 -6.8 147 0.7
9250 0.1 32.2 305 17 9 8.4 4.6 5.7 42.3 -6.9 121 0.6
9000 0.6 33.1 305 17 9 6.9 3.8 5.6 42.0 -7.1 97 0.5
8750 1.1 34.0 300 17 9 7.0 3.9 5.3 41.6 -7.4 75 0.4
8500 1.6 34.9 300 17 9 5.1 2.8 5.1 41.2 -7.6 53 0.3
8250 1.8 35.2 300 17 9 1.2 0.7 4.6 40.3 -8.2 40 0.2
8000 1.8 35.2 295 17 9 0.4 0.2 3.9 39.0 -8.9 32 0.2
7750 -1.5 29.3 280 7 3 -81.8 -44.9 -0.8 30.5 -13.7 116 0.6
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 * * * * * *
03/24/2024 at 0900 MDT | 03/24/2024 at 1200 MDT
|
CAPE... +43.8 LI... +0.2 | CAPE... +558.5 LI... -2.1
CINH... -67.2 K Index... +13.2 | CINH... 0.0 K Index... +19.3
|
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 -54.7 -66.5 245 46 24 1.5 0.8 | -53.7 -64.7 240 46 24 1.9 1.1
45000 -52.4 -62.3 240 58 30 1.5 0.8 | -50.8 -59.4 240 52 27 1.9 1.1
40000 -52.6 -62.7 235 56 29 -0.5 -0.3 | -51.1 -60.0 235 48 25 -0.7 -0.4
38000 -52.9 -63.2 235 54 28 -1.0 -0.5 | -51.5 -60.7 230 46 24 -1.2 -0.7
36000 -53.6 -64.5 235 47 24 -1.1 -0.6 | -52.5 -62.5 225 39 20 -1.7 -0.9
34000 -54.3 -65.7 230 40 21 -1.1 -0.6 | -53.5 -64.3 220 32 16 -1.7 -0.9
32000 -53.4 -64.1 220 35 18 2.9 1.6 | -52.7 -62.9 215 27 14 3.0 1.6
30000 -51.6 -60.9 210 33 17 3.1 1.7 | -50.9 -59.6 205 25 13 3.0 1.7
29000 -49.9 -57.8 205 32 17 8.8 4.9 | -49.7 -57.5 200 23 12 6.9 3.8
28000 -47.3 -53.1 210 32 16 8.9 4.9 | -47.7 -53.9 210 20 10 6.6 3.6
27000 -44.6 -48.3 215 32 16 8.9 4.9 | -45.2 -49.4 225 16 8 6.6 3.6
26000 -41.3 -42.3 220 30 16 8.4 4.6 | -43.0 -45.4 235 15 8 9.4 5.2
25000 -38.8 -37.8 220 27 14 8.4 4.6 | -40.2 -40.4 235 16 8 9.4 5.2
24000 -36.2 -33.2 220 23 12 8.4 4.6 | -37.4 -35.3 235 18 9 9.4 5.2
23000 -33.7 -28.7 220 20 10 8.6 4.7 | -34.6 -30.3 230 19 10 8.9 4.9
22000 -31.1 -24.0 220 19 10 8.6 4.7 | -31.9 -25.4 230 20 10 8.9 4.9
21000 -28.6 -19.5 220 19 10 8.6 4.7 | -29.3 -20.7 230 20 10 8.8 4.9
20000 -26.1 -15.0 220 19 10 8.4 4.6 | -26.7 -16.1 225 20 10 8.2 4.5
19500 -24.8 -12.6 220 19 10 8.4 4.6 | -25.5 -13.9 225 20 10 8.2 4.5
19000 -23.5 -10.3 220 19 10 8.4 4.6 | -24.3 -11.7 225 19 10 8.2 4.5
18500 -22.3 -8.1 220 19 10 8.4 4.6 | -23.1 -9.6 225 19 10 8.2 4.5
18000 -21.0 -5.8 220 19 10 8.5 4.7 | -21.8 -7.2 225 19 10 8.2 4.5
17500 -19.7 -3.5 220 19 10 8.9 4.9 | -20.6 -5.1 225 18 10 8.3 4.5
17000 -18.4 -1.1 220 20 10 8.9 4.9 | -19.4 -2.9 225 18 9 8.3 4.6
16500 -17.2 1.0 225 20 10 8.0 4.4 | -18.2 -0.8 230 18 9 8.0 4.4
16000 -16.0 3.2 225 19 10 8.1 4.4 | -17.0 1.4 230 16 8 8.0 4.4
15500 -14.8 5.4 225 19 10 8.0 4.4 | -15.8 3.6 230 14 7 8.0 4.4
15000 -13.6 7.5 225 17 9 7.9 4.3 | -14.6 5.7 225 12 6 8.1 4.4
14500 -12.4 9.7 230 15 8 7.7 4.2 | -13.5 7.7 220 9 5 8.1 4.4
14000 -11.4 11.5 225 12 6 7.0 3.9 | -12.3 9.9 200 6 3 7.6 4.2
13500 -10.4 13.3 225 8 4 6.9 3.8 | -11.2 11.8 160 6 3 7.7 4.2
13000 -9.5 14.9 215 5 3 5.0 2.7 | -10.1 13.8 130 8 4 6.8 3.8
12500 -8.4 16.9 175 2 1 9.3 5.1 | -9.0 15.8 115 11 5 8.6 4.7
12000 -7.2 19.0 080 2 1 7.9 4.4 | -7.8 18.0 105 11 6 8.4 4.6
11750 -6.6 20.1 050 2 1 7.9 4.3 | -7.2 19.0 100 11 6 8.4 4.6
11500 -6.0 21.2 035 4 2 8.7 4.8 | -6.6 20.1 095 10 5 8.6 4.7
11250 -5.4 22.3 020 5 2 9.3 5.1 | -5.9 21.4 090 10 5 9.5 5.2
11000 -4.7 23.5 015 4 2 9.0 4.9 | -5.2 22.6 090 9 5 10.2 5.6
10750 -4.0 24.8 015 4 2 9.2 5.1 | -4.4 24.1 090 9 5 10.5 5.8
10500 -3.3 26.1 010 4 2 8.7 4.7 | -3.7 25.3 085 9 5 9.4 5.2
10250 -2.7 27.1 005 5 2 8.2 4.5 | -3.0 26.6 085 9 5 8.3 4.5
10000 -2.1 28.2 005 4 2 8.5 4.6 | -1.7 28.9 080 9 5 10.1 5.5
9750 -1.5 29.3 005 4 2 8.3 4.6 | -0.9 30.4 080 9 4 9.4 5.2
9500 -0.9 30.4 005 3 2 8.7 4.8 | -0.2 31.6 080 9 4 11.4 6.3
9250 -0.2 31.6 005 3 2 8.9 4.9 | 0.7 33.3 080 8 4 10.9 6.0
9000 0.4 32.7 350 3 1 7.9 4.3 | 1.4 34.5 080 8 4 8.7 4.8
8750 1.5 34.7 315 3 1 7.1 3.9 | 2.1 35.8 080 8 4 9.1 5.0
8500 2.0 35.6 300 3 2 5.8 3.2 | 2.8 37.0 080 8 4 12.0 6.6
8250 2.4 36.3 285 4 2 5.1 2.8 | 3.9 39.0 075 8 4 16.5 9.1
8000 2.7 36.9 275 4 2 5.1 2.8 | 5.1 41.2 075 8 4 16.9 9.3
7750 3.0 37.4 270 4 2 5.1 2.8 | 6.4 43.5 075 7 4 18.4 10.1
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
03/24/2024 at 1500 MDT | 03/24/2024 at 1800 MDT
|
CAPE... +457.6 LI... -1.7 | CAPE... +4.1 LI... -0.0
CINH... -15.8 K Index... +22.9 | CINH... -2.4 K Index... +22.5
|
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 -53.5 -64.3 230 45 23 2.0 1.1 | -52.9 -63.2 235 46 24 2.0 1.1
45000 -50.4 -58.7 250 44 23 2.0 1.1 | -50.0 -58.0 240 37 19 2.0 1.1
40000 -50.7 -59.3 240 43 22 -0.7 -0.4 | -51.0 -59.8 230 40 20 -1.2 -0.7
38000 -51.2 -60.2 230 43 22 -1.9 -1.0 | -51.7 -61.1 230 42 22 -3.3 -1.8
36000 -53.0 -63.4 230 36 18 -3.0 -1.7 | -54.9 -66.8 230 27 14 -5.3 -2.9
34000 -54.8 -66.6 230 28 15 -3.1 -1.7 | -58.0 -72.4 240 13 7 -5.3 -2.9
32000 -54.0 -65.2 240 23 12 3.9 2.1 | -56.3 -69.3 260 5 3 7.5 4.1
30000 -51.7 -61.1 265 20 10 3.9 2.2 | -51.8 -61.2 335 3 1 7.5 4.1
29000 -50.0 -58.0 270 19 10 8.9 4.9 | -49.3 -56.7 005 3 2 9.7 5.3
28000 -47.4 -53.3 275 17 9 8.6 4.7 | -46.4 -51.5 020 3 2 9.7 5.3
27000 -44.8 -48.6 275 15 8 8.6 4.7 | -43.5 -46.3 035 4 2 9.7 5.3
26000 -42.2 -44.0 280 13 7 8.8 4.8 | -40.6 -41.1 045 4 2 9.4 5.2
25000 -38.9 -38.0 265 12 6 9.1 5.0 | -37.1 -34.8 050 5 3 9.2 5.1
24000 -36.1 -33.0 250 12 6 9.1 5.0 | -34.4 -29.9 050 6 3 9.2 5.1
23000 -33.5 -28.3 235 13 6 8.7 4.8 | -31.7 -25.1 055 7 3 8.7 4.8
22000 -30.9 -23.6 225 12 6 8.7 4.8 | -29.1 -20.4 055 7 4 8.7 4.8
21000 -28.3 -18.9 215 13 7 8.7 4.8 | -26.5 -15.7 060 8 4 8.7 4.8
20000 -25.7 -14.3 200 14 7 8.2 4.5 | -24.0 -11.2 060 9 5 7.8 4.3
19500 -24.5 -12.1 195 13 7 8.2 4.5 | -22.8 -9.0 060 10 5 7.8 4.3
19000 -23.3 -9.9 185 14 7 8.2 4.5 | -21.7 -7.1 060 10 5 7.8 4.3
18500 -22.1 -7.8 180 14 7 8.2 4.5 | -20.5 -4.9 060 11 5 7.9 4.3
18000 -20.9 -5.6 170 15 8 8.3 4.5 | -19.3 -2.7 060 11 6 7.9 4.3
17500 -19.7 -3.5 165 15 8 7.2 4.0 | -18.2 -0.8 060 12 6 7.6 4.1
17000 -18.6 -1.5 155 15 8 7.3 4.0 | -17.1 1.2 060 13 6 7.6 4.2
16500 -17.6 0.3 150 15 8 7.3 4.0 | -16.0 3.2 060 13 7 7.4 4.1
16000 -16.5 2.3 140 16 8 7.4 4.0 | -14.9 5.2 060 14 7 7.3 4.0
15500 -15.4 4.3 135 16 8 7.6 4.2 | -13.8 7.2 055 15 8 7.3 4.0
15000 -14.2 6.4 125 16 8 8.4 4.6 | -12.8 9.0 055 16 8 7.2 3.9
14500 -13.0 8.6 120 16 8 8.4 4.6 | -11.7 10.9 055 17 9 7.2 4.0
14000 -11.8 10.8 115 16 8 8.4 4.6 | -10.7 12.7 055 18 9 6.7 3.7
13500 -10.5 13.1 105 16 8 8.5 4.7 | -9.7 14.5 055 19 10 6.7 3.7
13000 -9.4 15.1 100 16 8 7.4 4.0 | -8.7 16.3 055 20 10 7.6 4.2
12500 -8.3 17.1 095 15 8 7.7 4.2 | -7.7 18.1 055 21 11 6.4 3.5
12000 -7.1 19.2 095 15 8 9.2 5.1 | -6.7 19.9 050 21 11 6.8 3.7
11750 -6.4 20.5 090 14 7 9.7 5.3 | -6.2 20.8 050 22 11 7.0 3.8
11500 -5.7 21.7 090 14 7 8.1 4.4 | -5.8 21.6 050 22 11 6.4 3.5
11250 -5.2 22.6 090 14 7 7.6 4.1 | -5.3 22.5 050 22 11 5.9 3.2
11000 -4.5 23.9 085 14 7 9.2 5.1 | -4.9 23.2 050 22 11 6.5 3.6
10750 -3.8 25.2 085 13 7 10.0 5.5 | -3.9 25.0 050 22 11 6.6 3.6
10500 -3.1 26.4 080 13 7 8.7 4.8 | -3.5 25.7 050 22 11 4.8 2.6
10250 -2.6 27.3 080 13 7 6.2 3.4 | -3.2 26.2 050 22 11 4.6 2.5
10000 -2.1 28.2 075 13 6 8.3 4.5 | -2.8 27.0 045 21 11 5.6 3.1
9750 -1.3 29.7 070 12 6 10.2 5.6 | -2.4 27.7 045 21 11 5.5 3.0
9500 -0.6 30.9 070 12 6 10.5 5.8 | -2.0 28.4 045 20 11 5.0 2.8
9250 0.5 32.9 060 12 6 6.4 3.5 | -1.7 28.9 045 20 10 3.7 2.0
9000 1.1 34.0 060 11 6 9.4 5.1 | -1.5 29.3 040 19 10 3.2 1.8
8750 1.8 35.2 055 11 6 8.0 4.4 | -1.2 29.8 040 18 9 3.2 1.8
8500 2.4 36.3 050 11 6 10.5 5.7 | -1.0 30.2 035 17 9 3.7 2.0
8250 3.3 37.9 045 10 5 12.7 7.0 | -0.7 30.7 030 15 7 5.3 2.9
8000 4.1 39.4 045 9 5 10.0 5.5 | -0.2 31.6 020 10 5 6.3 3.5
7750 5.0 41.0 040 7 4 16.8 9.2 | 0.2 32.4 010 7 3 4.9 2.7
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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