Soaring Guidance
Issued by NWS Pueblo, CO
Issued by NWS Pueblo, CO
900
UXUS97 KPUB 011213
SRGPUB
Soaring Forecast
National Weather Service Pueblo, Colorado
0613 MDT Wednesday, May 1, 2024
This forecast is for the Air Force Academy for Wednesday, May 1, 2024:
If the trigger temperature of 56.1 F/13.4 C is reached...then
Thermal Soaring Index....................... Excellent
Maximum rate of lift........................ 966 ft/min (4.9 m/s)
Maximum height of thermals.................. 18074 ft MSL (10464 ft AGL)
Forecast maximum temperature................... 66.0 F/19.3 C
Time of trigger temperature.................... 1045 MDT
Time of overdevelopment........................ 1500 MDT
Middle/high clouds during soaring window....... None
Surface winds during soaring window............ 20 mph or less
Height of the -3 thermal index................. 15104 ft MSL (7494 ft AGL)
Thermal soaring outlook for Thursday 05/02..... Good
Wave Soaring Index............................. Not available
Remarks...
Sunrise/Sunset.................... 06:00:12 / 19:52:23 MDT
Total possible sunshine........... 13 hr 52 min 11 sec (832 min 11 sec)
Altitude of sun at 12:56:18 MDT... 66.41 degrees
Upper air data from numerical model forecast valid on 05/01/2024 at 0600 MDT
Freezing level.................. 12676 ft MSL (5066 ft AGL)
Convective condensation level... 16130 ft MSL (8520 ft AGL)
Lifted condensation level....... 17263 ft MSL (9653 ft AGL)
Lifted index.................... -0.2
K index......................... +8.4
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 -58.6 -73.5 255 48 25 1.8 1.0 M M M M M
45000 -56.2 -69.2 255 60 31 -1.8 -1.0 M M M M M
40000 -58.4 -73.1 260 68 35 -1.5 -0.8 M M M M M
38000 -56.9 -70.4 255 67 34 5.1 2.8 M M M M M
36000 -53.4 -64.1 255 62 32 5.1 2.8 M M M M M
34000 -49.7 -57.5 250 58 30 8.3 4.5 M M M M M
32000 -44.7 -48.5 250 56 29 8.3 4.5 M M M M M
30000 -39.8 -39.6 250 53 27 8.1 4.4 28.9 84.0 7.7 M M
29000 -37.4 -35.3 245 52 27 8.1 4.4 28.2 82.7 7.3 M M
28000 -35.0 -31.0 245 51 26 8.1 4.4 27.6 81.7 6.9 M M
27000 -32.5 -26.5 245 50 26 7.9 4.3 27.1 80.7 6.6 M M
26000 -30.2 -22.4 240 49 25 7.9 4.3 26.3 79.3 6.0 M M
25000 -27.8 -18.0 240 48 25 7.9 4.3 25.6 78.0 5.5 M M
24000 -25.5 -13.9 240 48 24 7.5 4.1 25.0 77.0 5.1 M M
23000 -23.4 -10.1 245 47 24 7.0 3.9 23.9 75.1 4.2 M M
22000 -20.8 -5.4 245 46 24 7.0 3.9 22.7 72.9 3.3 M M
21000 -18.7 -1.7 250 45 23 7.0 3.9 21.8 71.3 2.5 M M
20000 -16.6 2.1 250 45 23 7.1 3.9 20.8 69.5 1.6 M M
19500 -15.5 4.1 250 44 23 7.1 3.9 20.4 68.7 1.3 M M
19000 -14.5 5.9 250 44 23 7.2 3.9 20.0 68.0 0.9 M M
18500 -13.5 7.7 250 44 23 6.1 3.3 19.5 67.1 0.4 M M
18000 -12.6 9.3 250 43 22 6.2 3.4 18.9 66.0 -0.2 955 4.8
17500 -11.7 10.9 250 42 22 6.1 3.3 18.3 64.9 -0.7 913 4.6
17000 -10.8 12.6 250 41 21 6.0 3.3 17.6 63.7 -1.3 872 4.4
16500 -10.0 14.0 250 40 21 5.9 3.2 17.0 62.6 -1.9 832 4.2
16000 -9.0 15.8 255 39 20 7.9 4.4 16.6 61.8 -2.4 787 4.0
15500 -7.9 17.8 250 38 20 7.7 4.2 16.2 61.2 -2.8 739 3.8
15000 -6.7 19.9 250 38 19 9.3 5.1 16.0 60.8 -3.0 688 3.5
14500 -5.2 22.6 250 37 19 9.6 5.3 16.0 60.8 -3.1 630 3.2
14000 -3.8 25.2 250 36 19 9.5 5.2 16.0 60.8 -3.1 572 2.9
13500 -2.4 27.7 250 35 18 9.4 5.2 15.9 60.6 -3.2 515 2.6
13000 -1.0 30.2 245 35 18 10.5 5.7 15.8 60.5 -3.3 458 2.3
12500 0.3 32.5 245 34 17 5.7 3.1 15.7 60.2 -3.5 405 2.1
12000 1.2 34.2 240 32 16 4.6 2.5 15.1 59.1 -4.1 364 1.9
11750 1.3 34.3 235 30 16 0.1 0.1 14.5 58.1 -4.7 352 1.8
11500 1.3 34.3 225 28 15 0.6 0.3 13.7 56.7 -5.5 347 1.8
11250 1.4 34.5 220 27 14 3.3 1.8 13.1 55.6 -6.1 335 1.7
11000 1.6 34.9 215 26 14 2.0 1.1 12.6 54.7 -6.6 321 1.6
10750 1.7 35.1 205 26 14 -0.7 -0.4 11.9 53.4 -7.3 313 1.6
10500 1.5 34.7 200 27 14 -1.8 -1.0 11.0 51.8 -8.2 310 1.6
10250 1.4 34.5 195 28 15 -1.6 -0.9 10.1 50.2 -9.1 306 1.6
10000 1.2 34.2 190 29 15 -0.8 -0.4 9.3 48.7 -10.0 303 1.5
9750 1.2 34.2 185 30 15 0.6 0.3 8.5 47.3 -10.8 296 1.5
9500 1.3 34.3 180 30 16 1.9 1.0 7.9 46.1 -11.5 286 1.5
9250 1.4 34.5 180 31 16 -1.6 -0.9 7.2 45.0 -12.1 277 1.4
9000 1.1 34.0 175 32 17 -2.1 -1.2 6.2 43.2 -13.2 277 1.4
8750 1.2 34.2 175 32 16 2.1 1.1 5.5 41.9 -13.9 269 1.4
8500 1.4 34.5 175 31 16 2.6 1.4 4.9 40.9 -14.5 256 1.3
8250 1.5 34.7 170 30 15 1.2 0.7 4.4 39.9 -15.0 243 1.2
8000 1.5 34.7 170 28 15 -0.6 -0.3 3.7 38.6 -15.8 235 1.2
7750 1.5 34.7 175 21 11 0.5 0.3 2.9 37.2 -16.6 228 1.2
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 * * * * * *
05/01/2024 at 0900 MDT | 05/01/2024 at 1200 MDT
|
CAPE... 0.0 LI... +1.7 | CAPE... +47.0 LI... +0.8
CINH... 0.0 K Index... +1.6 | CINH... -18.4 K Index... +2.8
|
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 -57.4 -71.3 250 48 25 0.6 0.3 | -57.4 -71.3 255 40 21 -0.3 -0.2
45000 -56.6 -69.9 250 61 31 -1.8 -1.0 | -57.9 -72.2 245 65 33 -1.0 -0.5
40000 -58.9 -74.0 250 75 39 -1.6 -0.9 | -59.3 -74.7 240 71 36 -1.0 -0.5
38000 -56.4 -69.5 250 74 38 6.3 3.4 | -56.8 -70.2 240 71 37 7.1 3.9
36000 -52.7 -62.9 245 69 36 6.3 3.4 | -52.0 -61.6 240 71 36 7.1 3.9
34000 -48.6 -55.5 245 65 33 7.7 4.2 | -47.7 -53.9 240 70 36 7.1 3.9
32000 -44.0 -47.2 240 60 31 7.6 4.2 | -43.4 -46.1 235 69 35 7.1 3.9
30000 -39.3 -38.7 240 56 29 8.1 4.4 | -39.1 -38.4 235 66 34 7.2 4.0
29000 -36.9 -34.4 240 55 28 8.1 4.4 | -37.0 -34.6 235 64 33 7.2 4.0
28000 -34.5 -30.1 240 54 28 8.1 4.4 | -34.8 -30.6 235 62 32 7.2 4.0
27000 -32.1 -25.8 235 53 27 7.1 3.9 | -32.7 -26.9 235 60 31 7.1 3.9
26000 -30.0 -22.0 235 52 27 6.9 3.8 | -30.5 -22.9 240 58 30 7.0 3.9
25000 -28.0 -18.4 240 51 26 6.9 3.8 | -28.4 -19.1 240 55 28 7.0 3.9
24000 -25.9 -14.6 240 50 26 6.9 3.8 | -26.3 -15.3 240 53 27 6.9 3.8
23000 -23.8 -10.8 240 48 25 6.9 3.8 | -24.3 -11.7 240 51 26 6.7 3.7
22000 -21.8 -7.2 240 46 24 6.9 3.8 | -22.3 -8.1 240 49 25 6.7 3.7
21000 -19.1 -2.4 245 44 23 7.6 4.2 | -19.6 -3.3 240 47 24 8.9 4.9
20000 -16.9 1.6 245 43 22 7.5 4.1 | -16.9 1.6 235 44 23 8.7 4.8
19500 -15.8 3.6 245 42 22 7.5 4.1 | -15.6 3.9 235 43 22 8.7 4.8
19000 -14.6 5.7 245 42 22 7.4 4.1 | -14.3 6.3 235 41 21 8.7 4.8
18500 -13.4 7.9 245 40 21 8.8 4.8 | -13.0 8.6 235 38 20 8.7 4.8
18000 -12.1 10.2 240 36 19 8.7 4.8 | -11.7 10.9 230 32 17 8.7 4.8
17500 -10.8 12.6 235 33 17 7.8 4.3 | -10.4 13.3 220 27 14 7.9 4.3
17000 -9.8 14.4 240 33 17 6.6 3.6 | -9.4 15.1 225 30 16 6.8 3.7
16500 -8.8 16.2 245 34 18 6.8 3.7 | -8.4 16.9 235 35 18 7.0 3.9
16000 -8.1 17.4 245 35 18 4.1 2.3 | -7.7 18.1 240 37 19 3.1 1.7
15500 -7.5 18.5 250 36 19 4.4 2.4 | -7.2 19.0 245 37 19 3.5 1.9
15000 -6.8 19.8 250 37 19 7.3 4.0 | -6.6 20.1 250 36 19 7.0 3.8
14500 -5.6 21.9 250 35 18 7.9 4.3 | -5.5 22.1 250 33 17 7.9 4.3
14000 -4.5 23.9 250 34 18 8.8 4.8 | -4.4 24.1 250 29 15 8.8 4.9
13500 -3.1 26.4 250 33 17 9.7 5.3 | -3.0 26.6 250 27 14 9.7 5.3
13000 -1.6 29.1 250 33 17 11.8 6.5 | -1.6 29.1 250 26 13 11.6 6.4
12500 0.0 32.0 250 32 17 8.3 4.6 | -0.0 32.0 250 25 13 7.8 4.3
12000 1.3 34.3 250 32 16 8.6 4.7 | 1.2 34.2 250 23 12 8.7 4.7
11750 1.9 35.4 250 31 16 7.4 4.1 | 1.9 35.4 245 22 12 9.3 5.1
11500 2.5 36.5 250 31 16 8.0 4.4 | 2.6 36.7 245 22 11 8.7 4.8
11250 3.2 37.8 250 31 16 9.4 5.2 | 3.2 37.8 245 21 11 8.2 4.5
11000 3.8 38.8 250 30 16 7.6 4.2 | 3.8 38.8 245 20 10 8.2 4.5
10750 4.2 39.6 250 29 15 3.7 2.0 | 4.4 39.9 240 19 10 7.2 4.0
10500 4.4 39.9 245 28 14 2.0 1.1 | 4.9 40.8 240 18 9 7.5 4.1
10250 4.7 40.5 240 27 14 6.1 3.4 | 5.5 41.9 235 17 9 10.0 5.5
10000 5.2 41.4 240 26 13 5.3 2.9 | 6.3 43.3 235 17 9 10.1 5.5
9750 5.3 41.5 235 25 13 -1.8 -1.0 | 7.0 44.6 235 16 8 7.9 4.3
9500 5.1 41.2 230 24 12 -3.5 -1.9 | 7.5 45.5 230 15 8 6.3 3.5
9250 4.8 40.6 225 23 12 -3.5 -1.9 | 8.0 46.4 225 15 8 9.5 5.2
9000 4.5 40.1 215 22 11 -2.6 -1.4 | 8.9 48.0 220 14 7 12.2 6.7
8750 4.4 39.9 210 21 11 -0.7 -0.4 | 9.7 49.5 215 13 7 10.2 5.6
8500 4.3 39.7 205 20 10 -0.5 -0.3 | 10.5 50.9 210 13 7 10.3 5.7
8250 4.3 39.7 195 20 10 -0.6 -0.3 | 11.2 52.2 210 13 7 8.2 4.5
8000 4.5 40.1 185 18 9 9.8 5.4 | 11.9 53.4 205 13 6 14.3 7.8
7750 5.9 42.6 180 16 8 26.8 14.7 | 13.6 56.5 200 12 6 31.9 17.5
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
05/01/2024 at 1500 MDT | 05/01/2024 at 1800 MDT
|
CAPE... +268.0 LI... -1.6 | CAPE... +277.2 LI... -1.2
CINH... -7.7 K Index... +26.9 | CINH... -7.4 K Index... +28.0
|
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 -56.8 -70.2 250 37 19 0.8 0.5 | -56.4 -69.5 245 35 18 1.4 0.7
45000 -55.7 -68.3 245 68 35 -2.0 -1.1 | -54.6 -66.3 250 62 32 -2.2 -1.2
40000 -59.1 -74.4 240 77 40 -2.3 -1.3 | -59.1 -74.4 240 80 41 -2.8 -1.5
38000 -56.8 -70.2 240 79 41 6.8 3.7 | -57.2 -71.0 240 81 42 6.0 3.3
36000 -52.7 -62.9 240 80 41 6.8 3.7 | -53.6 -64.5 235 80 41 6.0 3.3
34000 -48.6 -55.5 240 80 41 7.1 3.9 | -49.9 -57.8 235 77 40 6.6 3.6
32000 -44.3 -47.7 240 77 39 7.1 3.9 | -45.9 -50.6 235 71 37 6.6 3.6
30000 -40.0 -40.0 240 73 38 7.3 4.0 | -41.7 -43.1 235 65 33 7.7 4.2
29000 -37.8 -36.0 240 71 37 7.3 4.0 | -39.4 -38.9 235 60 31 7.7 4.2
28000 -35.7 -32.3 240 70 36 7.3 4.0 | -37.1 -34.8 235 56 29 7.7 4.2
27000 -33.5 -28.3 240 68 35 6.9 3.8 | -34.8 -30.6 235 51 26 7.9 4.3
26000 -31.4 -24.5 240 65 33 6.8 3.7 | -32.4 -26.3 235 46 24 8.0 4.4
25000 -29.4 -20.9 240 62 32 6.8 3.7 | -30.0 -22.0 235 41 21 8.0 4.4
24000 -27.4 -17.3 240 59 31 6.7 3.7 | -27.6 -17.7 235 36 18 8.2 4.5
23000 -25.4 -13.7 245 56 29 6.6 3.6 | -24.5 -12.1 240 32 16 8.5 4.7
22000 -23.0 -9.4 245 53 27 6.7 3.7 | -22.0 -7.6 240 29 15 8.6 4.7
21000 -20.8 -5.4 250 49 25 9.5 5.2 | -19.5 -3.1 240 26 14 8.2 4.5
20000 -18.1 -0.6 245 42 22 9.3 5.1 | -17.1 1.2 240 25 13 8.2 4.5
19500 -16.7 1.9 245 39 20 9.4 5.1 | -15.9 3.4 240 24 12 8.3 4.5
19000 -15.3 4.5 245 35 18 9.4 5.2 | -14.7 5.5 240 23 12 8.3 4.6
18500 -14.0 6.8 245 32 17 9.2 5.0 | -13.5 7.7 240 23 12 7.6 4.2
18000 -12.6 9.3 245 29 15 9.1 5.0 | -12.4 9.7 245 23 12 7.6 4.2
17500 -11.3 11.7 245 27 14 8.5 4.7 | -11.3 11.7 245 22 12 7.6 4.1
17000 -10.2 13.6 245 25 13 7.4 4.1 | -10.2 13.6 245 22 11 7.5 4.1
16500 -9.1 15.6 245 24 12 7.3 4.0 | -9.1 15.6 245 21 11 7.5 4.1
16000 -8.0 17.6 245 23 12 7.9 4.3 | -8.0 17.6 245 20 10 7.6 4.2
15500 -6.9 19.6 245 22 11 7.8 4.3 | -6.9 19.6 245 19 10 7.6 4.2
15000 -5.7 21.7 245 21 11 9.1 5.0 | -5.8 21.6 245 18 9 7.7 4.2
14500 -4.2 24.4 240 21 11 9.5 5.2 | -4.6 23.7 245 18 9 7.7 4.2
14000 -2.8 27.0 240 21 11 9.6 5.2 | -3.5 25.7 250 17 9 8.7 4.8
13500 -1.4 29.5 240 20 10 9.8 5.4 | -2.0 28.4 250 16 8 10.0 5.5
13000 0.1 32.2 240 20 10 12.8 7.0 | -0.6 30.9 250 15 8 13.0 7.1
12500 1.7 35.1 235 19 10 6.9 3.8 | 1.2 34.2 250 14 7 7.8 4.3
12000 2.9 37.2 235 18 9 8.3 4.6 | 2.5 36.5 250 13 7 8.9 4.9
11750 3.6 38.5 230 18 9 10.0 5.5 | 3.2 37.8 250 12 6 9.6 5.3
11500 4.3 39.7 230 18 9 9.4 5.2 | 3.9 39.0 255 11 6 9.7 5.3
11250 5.0 41.0 225 17 9 8.4 4.6 | 4.6 40.3 255 11 6 9.5 5.2
11000 5.6 42.1 225 17 9 8.6 4.7 | 5.4 41.7 255 10 5 9.4 5.2
10750 6.3 43.3 220 17 9 8.0 4.4 | 6.0 42.8 260 9 5 8.2 4.5
10500 6.8 44.2 220 16 8 8.2 4.5 | 6.6 43.9 260 9 5 8.3 4.6
10250 7.5 45.5 215 16 8 9.7 5.3 | 7.3 45.1 265 8 4 10.3 5.6
10000 8.2 46.8 210 16 8 10.0 5.5 | 8.1 46.6 270 8 4 10.7 5.8
9750 9.0 48.2 205 15 8 9.2 5.0 | 8.9 48.0 275 7 4 9.8 5.4
9500 9.6 49.3 200 15 8 8.6 4.7 | 9.6 49.3 280 7 4 9.1 5.0
9250 10.3 50.5 195 15 8 9.3 5.1 | 10.3 50.5 285 7 3 10.3 5.6
9000 11.0 51.8 195 15 8 10.0 5.5 | 11.1 52.0 290 6 3 11.0 6.0
8750 11.7 53.1 190 15 8 9.8 5.4 | 11.9 53.4 295 6 3 9.6 5.3
8500 12.5 54.5 190 15 8 9.8 5.4 | 12.6 54.7 300 6 3 8.9 4.9
8250 13.2 55.8 185 15 8 9.4 5.1 | 13.2 55.8 305 6 3 9.6 5.3
8000 13.9 57.0 185 15 7 11.1 6.1 | 14.0 57.2 310 5 3 9.0 5.0
7750 14.9 58.8 185 13 7 16.1 8.8 | 14.5 58.1 315 4 2 6.1 3.3
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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