Soaring Guidance
Issued by NWS Pueblo, CO
Issued by NWS Pueblo, CO
205
UXUS97 KPUB 111212
SRGPUB
Soaring Forecast
National Weather Service Pueblo, Colorado
0612 MDT Saturday, May 11, 2024
This forecast is for the Air Force Academy for Saturday, May 11, 2024:
If the trigger temperature of 47.7 F/8.7 C is reached...then
Thermal Soaring Index....................... Fair
Maximum rate of lift........................ 299 ft/min (1.5 m/s)
Maximum height of thermals.................. 15920 ft MSL (8286 ft AGL)
Forecast maximum temperature................... 58.0 F/14.9 C
Time of trigger temperature.................... 0830 MDT
Time of overdevelopment........................ 1200 MDT
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................. 13437 ft MSL (5804 ft AGL)
Thermal soaring outlook for Sunday 05/12....... Fair
Wave Soaring Index............................. Not available
Remarks...
Sunrise/Sunset.................... 05:49:25 / 20:01:54 MDT
Total possible sunshine........... 14 hr 12 min 29 sec (852 min 29 sec)
Altitude of sun at 12:55:39 MDT... 69.15 degrees
Upper air data from numerical model forecast valid on 05/11/2024 at 0600 MDT
Freezing level.................. 9068 ft MSL (1434 ft AGL)
Convective condensation level... 11597 ft MSL (3963 ft AGL)
Lifted condensation level....... 13955 ft MSL (6322 ft AGL)
Lifted index.................... -1.2
K index......................... +20.8
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 -55.5 -67.9 270 30 15 1.6 0.9 M M M M M
45000 -53.4 -64.1 255 29 15 -1.0 -0.6 M M M M M
40000 -54.7 -66.5 245 47 24 -0.9 -0.5 M M M M M
38000 -54.9 -66.8 240 49 25 -0.0 -0.0 M M M M M
36000 -54.9 -66.8 235 47 24 -0.0 -0.0 M M M M M
34000 -53.3 -63.9 230 44 23 8.0 4.4 M M M M M
32000 -48.5 -55.3 225 38 19 8.1 4.4 M M M M M
30000 -43.3 -45.9 225 33 17 9.4 5.1 24.9 76.8 8.0 M M
29000 -40.6 -41.1 225 33 17 9.3 5.1 24.7 76.4 8.0 M M
28000 -37.8 -36.0 220 33 17 9.4 5.1 24.6 76.2 8.0 M M
27000 -35.0 -31.0 220 32 17 8.5 4.6 24.4 76.0 8.0 M M
26000 -32.5 -26.5 210 31 16 8.5 4.7 23.9 75.0 7.6 M M
25000 -30.0 -22.0 205 31 16 8.5 4.7 23.4 74.2 7.3 M M
24000 -27.5 -17.5 200 31 16 7.8 4.3 23.1 73.5 7.1 M M
23000 -25.3 -13.5 190 30 16 7.4 4.1 22.1 71.9 6.3 M M
22000 -22.5 -8.5 180 30 15 7.4 4.1 21.2 70.1 5.6 M M
21000 -20.4 -4.7 175 29 15 6.6 3.6 20.2 68.4 4.8 M M
20000 -18.5 -1.3 170 28 14 6.7 3.7 19.1 66.5 3.9 M M
19500 -17.5 0.5 170 27 14 6.7 3.7 18.6 65.5 3.4 M M
19000 -16.5 2.3 165 26 13 6.7 3.7 18.2 64.7 3.0 M M
18500 -15.5 4.1 165 25 13 7.0 3.8 17.7 63.8 2.6 M M
18000 -14.5 5.9 165 23 12 7.0 3.8 17.2 63.0 2.2 M M
17500 -13.5 7.7 165 22 11 6.4 3.5 16.7 62.1 1.7 M M
17000 -12.6 9.3 160 21 11 6.2 3.4 16.1 61.0 1.2 M M
16500 -11.7 10.9 160 19 10 6.2 3.4 15.6 60.0 0.6 M M
16000 -10.7 12.7 160 17 9 6.3 3.4 15.0 59.0 0.1 M M
15500 -9.8 14.4 160 16 8 6.3 3.5 14.4 57.9 -0.5 662 3.4
15000 -8.9 16.0 155 14 7 6.1 3.3 13.8 56.9 -1.0 620 3.2
14500 -8.0 17.6 155 12 6 6.2 3.4 13.2 55.8 -1.6 579 2.9
14000 -7.2 19.0 155 10 5 5.7 3.1 12.6 54.8 -2.2 538 2.7
13500 -6.4 20.5 150 9 5 5.6 3.1 12.0 53.6 -2.9 499 2.5
13000 -5.5 22.1 145 7 4 5.9 3.3 11.4 52.4 -3.5 460 2.3
12500 -4.7 23.5 140 5 3 5.5 3.0 10.7 51.3 -4.2 420 2.1
12000 -3.9 25.0 135 5 2 5.5 3.0 10.1 50.1 -4.9 382 1.9
11750 -3.5 25.7 130 4 2 5.4 3.0 9.7 49.5 -5.2 363 1.8
11500 -3.1 26.4 130 3 2 5.6 3.1 9.4 48.9 -5.6 344 1.7
11250 -2.7 27.1 125 3 2 5.8 3.2 9.1 48.3 -5.9 324 1.6
11000 -2.3 27.9 120 3 1 5.1 2.8 8.7 47.7 -6.2 305 1.5
10750 -2.0 28.4 120 3 1 4.7 2.6 8.3 47.0 -6.7 287 1.5
10500 -1.7 28.9 120 2 1 4.4 2.4 8.0 46.3 -7.1 270 1.4
10250 -1.3 29.7 125 2 1 5.9 3.2 7.6 45.6 -7.5 252 1.3
10000 -0.9 30.4 125 2 1 5.1 2.8 7.3 45.2 -7.8 231 1.2
9750 -0.6 30.9 145 2 1 3.0 1.6 6.8 44.3 -8.3 216 1.1
9500 -0.4 31.3 155 2 1 3.9 2.1 6.3 43.4 -8.8 202 1.0
9250 -0.1 31.8 165 3 1 2.4 1.3 5.9 42.6 -9.3 187 0.9
9000 -0.0 32.0 175 4 2 1.1 0.6 5.2 41.4 -9.9 176 0.9
8750 0.1 32.2 185 5 3 1.4 0.8 4.6 40.3 -10.6 166 0.8
8500 0.2 32.4 185 7 3 1.5 0.8 4.0 39.1 -11.2 155 0.8
8250 0.3 32.5 190 8 4 1.0 0.6 3.3 38.0 -11.9 145 0.7
8000 0.6 33.1 205 9 4 4.2 2.3 2.2 35.9 -13.1 121 0.6
7750 0.8 33.4 225 7 4 -0.7 -0.4 1.7 35.0 -13.6 107 0.5
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 * * * * * *
05/11/2024 at 0900 MDT | 05/11/2024 at 1200 MDT
|
CAPE... +2.7 LI... -0.2 | CAPE... +93.5 LI... -1.3
CINH... 0.0 K Index... +19.1 | CINH... -40.4 K Index... +23.9
|
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 -55.4 -67.7 265 26 13 1.6 0.9 | -55.6 -68.1 260 28 15 1.2 0.7
45000 -53.1 -63.6 255 27 14 -1.2 -0.7 | -53.8 -64.8 250 33 17 -0.8 -0.5
40000 -54.8 -66.6 240 50 26 -1.1 -0.6 | -54.9 -66.8 235 49 25 -0.7 -0.4
38000 -54.7 -66.5 235 54 28 1.1 0.6 | -54.4 -65.9 230 52 27 1.8 1.0
36000 -54.0 -65.2 230 55 28 1.1 0.6 | -53.4 -64.1 225 52 27 1.8 1.0
34000 -52.0 -61.6 225 54 28 7.1 3.9 | -51.2 -60.2 220 52 27 6.5 3.5
32000 -47.8 -54.0 225 51 26 7.1 3.9 | -47.3 -53.1 210 49 25 6.5 3.5
30000 -43.3 -45.9 220 47 24 8.2 4.5 | -42.9 -45.2 205 48 25 9.0 4.9
29000 -40.9 -41.6 215 43 22 8.2 4.5 | -40.2 -40.4 205 48 25 9.0 4.9
28000 -38.4 -37.1 215 40 21 8.2 4.5 | -37.5 -35.5 205 49 25 9.0 4.9
27000 -35.9 -32.6 215 37 19 9.1 5.0 | -34.9 -30.8 205 48 25 8.4 4.6
26000 -33.2 -27.8 210 36 19 9.2 5.0 | -32.3 -26.1 210 47 24 8.4 4.6
25000 -30.5 -22.9 210 35 18 9.2 5.0 | -29.8 -21.6 210 45 23 8.4 4.6
24000 -27.7 -17.9 210 34 18 7.8 4.3 | -27.3 -17.1 210 43 22 7.5 4.1
23000 -25.7 -14.3 215 31 16 7.0 3.8 | -25.2 -13.4 215 40 21 7.1 3.9
22000 -23.6 -10.5 220 28 14 7.0 3.9 | -23.1 -9.6 220 37 19 7.1 3.9
21000 -20.9 -5.6 230 27 14 7.4 4.1 | -21.0 -5.8 225 35 18 7.2 3.9
20000 -18.8 -1.8 230 29 15 7.5 4.1 | -18.4 -1.1 230 33 17 7.3 4.0
19500 -17.7 0.1 235 30 16 7.5 4.1 | -17.3 0.9 230 33 17 7.4 4.0
19000 -16.6 2.1 235 32 16 7.6 4.2 | -16.3 2.7 235 32 17 7.5 4.1
18500 -15.4 4.3 235 32 16 8.5 4.6 | -15.2 4.6 235 31 16 7.1 3.9
18000 -14.1 6.6 240 31 16 8.4 4.6 | -14.2 6.4 235 30 15 7.2 3.9
17500 -12.9 8.8 240 30 15 7.5 4.1 | -13.1 8.4 235 28 14 7.3 4.0
17000 -11.9 10.6 240 28 15 7.2 4.0 | -12.1 10.2 230 25 13 7.3 4.0
16500 -10.8 12.6 245 27 14 7.4 4.0 | -11.0 12.2 230 21 11 7.4 4.1
16000 -9.7 14.5 245 25 13 7.9 4.3 | -9.9 14.2 225 19 10 7.6 4.2
15500 -8.5 16.7 245 22 12 7.9 4.4 | -8.8 16.2 220 17 9 7.6 4.2
15000 -7.4 18.7 245 21 11 8.1 4.5 | -7.7 18.1 215 16 8 8.4 4.6
14500 -6.2 20.8 245 19 10 8.4 4.6 | -6.4 20.5 215 18 9 8.3 4.6
14000 -5.3 22.5 240 18 9 3.9 2.2 | -5.3 22.5 215 18 9 8.0 4.4
13500 -4.8 23.4 235 17 9 3.3 1.8 | -4.1 24.6 210 18 9 8.0 4.4
13000 -4.4 24.1 230 16 8 5.1 2.8 | -3.0 26.6 205 19 10 7.3 4.0
12500 -3.6 25.5 215 15 8 4.6 2.5 | -2.0 28.4 205 19 10 6.0 3.3
12000 -2.9 26.8 205 15 8 4.6 2.5 | -1.2 29.8 200 18 9 5.1 2.8
11750 -2.6 27.3 205 15 8 4.8 2.6 | -0.9 30.4 200 18 9 4.4 2.4
11500 -2.3 27.9 200 15 8 4.5 2.5 | -0.5 31.1 200 18 9 4.7 2.6
11250 -2.0 28.4 195 15 8 4.1 2.2 | -0.2 31.6 195 18 9 5.1 2.8
11000 -1.7 28.9 190 15 8 3.7 2.0 | 0.2 32.4 195 18 9 3.7 2.0
10750 -1.4 29.5 185 14 7 3.5 1.9 | 0.4 32.7 190 18 9 2.5 1.4
10500 -1.2 29.8 185 13 7 3.4 1.9 | 0.5 32.9 190 18 9 2.5 1.4
10250 -0.9 30.4 180 12 6 4.0 2.2 | 0.8 33.4 190 18 9 4.8 2.6
10000 -0.6 30.9 170 11 6 4.1 2.2 | 1.1 34.0 190 18 9 4.4 2.4
9750 -0.4 31.3 165 10 5 3.5 1.9 | 1.3 34.3 185 18 9 2.3 1.2
9500 -0.1 31.8 155 9 4 3.9 2.1 | 1.5 34.7 185 19 10 2.1 1.1
9250 0.2 32.4 145 8 4 2.8 1.6 | 1.7 35.1 185 19 10 5.0 2.7
9000 0.4 32.7 135 7 3 3.5 1.9 | 2.2 36.0 180 20 10 7.7 4.2
8750 0.7 33.3 125 6 3 5.1 2.8 | 2.7 36.9 180 19 10 6.5 3.6
8500 1.0 33.8 110 6 3 4.4 2.4 | 3.2 37.8 175 18 9 6.8 3.8
8250 1.4 34.5 100 6 3 5.6 3.1 | 3.6 38.5 175 18 9 6.8 3.7
8000 2.0 35.6 095 4 2 12.3 6.8 | 4.3 39.7 170 17 9 14.6 8.0
7750 3.2 37.8 095 3 2 19.9 10.9 | 5.9 42.6 170 15 8 27.3 15.0
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
05/11/2024 at 1500 MDT | 05/11/2024 at 1800 MDT
|
CAPE... +220.6 LI... -1.5 | CAPE... +113.7 LI... -0.3
CINH... -34.1 K Index... +20.3 | CINH... -65.9 K Index... +15.3
|
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 -55.9 -68.6 260 29 15 1.6 0.9 | -55.2 -67.4 270 27 14 1.7 0.9
45000 -53.6 -64.5 250 32 16 -0.6 -0.3 | -52.9 -63.2 260 28 14 0.0 0.0
40000 -54.4 -65.9 230 47 24 -0.6 -0.3 | -52.8 -63.0 240 41 21 0.1 0.1
38000 -53.8 -64.8 225 50 26 1.9 1.1 | -52.3 -62.1 235 44 23 1.1 0.6
36000 -52.7 -62.9 225 49 25 1.9 1.1 | -51.7 -61.1 230 45 23 1.1 0.6
34000 -50.5 -58.9 220 49 25 6.2 3.4 | -50.0 -58.0 230 46 24 5.9 3.2
32000 -46.8 -52.2 215 47 24 6.2 3.4 | -46.5 -51.7 230 45 23 6.0 3.3
30000 -42.7 -44.9 210 45 23 8.2 4.5 | -42.5 -44.5 230 44 23 7.8 4.3
29000 -40.2 -40.4 210 45 23 8.2 4.5 | -40.2 -40.4 225 42 22 7.8 4.3
28000 -37.7 -35.9 210 45 23 8.2 4.5 | -37.9 -36.2 225 40 21 7.8 4.3
27000 -35.2 -31.4 205 44 23 8.7 4.8 | -35.5 -31.9 225 38 20 8.6 4.7
26000 -32.6 -26.7 205 43 22 8.8 4.8 | -32.9 -27.2 225 37 19 8.7 4.8
25000 -30.0 -22.0 205 42 22 8.8 4.8 | -30.3 -22.5 220 37 19 8.7 4.8
24000 -27.4 -17.3 205 42 21 8.3 4.6 | -27.7 -17.9 220 36 19 8.4 4.6
23000 -25.0 -13.0 205 41 21 8.0 4.4 | -25.3 -13.5 215 35 18 8.0 4.4
22000 -22.6 -8.7 210 40 20 8.0 4.4 | -22.9 -9.2 215 35 18 8.0 4.4
21000 -20.3 -4.5 210 39 20 6.3 3.5 | -20.5 -4.9 215 34 18 7.5 4.1
20000 -17.9 -0.2 215 37 19 6.3 3.4 | -18.3 -0.9 215 33 17 7.4 4.1
19500 -17.0 1.4 220 36 19 6.3 3.5 | -16.6 2.1 215 32 17 7.4 4.1
19000 -16.1 3.0 220 35 18 6.4 3.5 | -15.5 4.1 215 32 16 7.4 4.1
18500 -15.0 5.0 220 34 18 8.6 4.7 | -14.4 6.1 215 31 16 7.3 4.0
18000 -13.8 7.2 220 33 17 8.5 4.7 | -13.4 7.9 220 29 15 7.5 4.1
17500 -12.6 9.3 225 31 16 8.1 4.4 | -12.3 9.9 220 27 14 8.3 4.5
17000 -11.5 11.3 225 28 15 7.9 4.3 | -11.0 12.2 220 25 13 8.8 4.8
16500 -10.3 13.5 225 26 13 7.8 4.3 | -9.8 14.4 215 22 12 8.6 4.7
16000 -9.3 15.3 225 22 11 7.3 4.0 | -8.8 16.2 215 19 10 5.6 3.1
15500 -8.2 17.2 220 18 9 7.2 4.0 | -8.0 17.6 210 16 8 5.7 3.1
15000 -7.1 19.2 215 16 8 8.1 4.5 | -7.0 19.4 200 14 7 8.4 4.6
14500 -5.9 21.4 215 15 8 8.1 4.5 | -5.7 21.7 200 12 6 8.5 4.7
14000 -4.8 23.4 210 15 8 7.9 4.3 | -4.5 23.9 195 11 6 8.3 4.5
13500 -3.6 25.5 205 15 8 7.9 4.3 | -3.3 26.1 190 11 6 8.2 4.5
13000 -2.5 27.5 205 15 8 8.6 4.7 | -2.1 28.2 190 11 6 7.7 4.2
12500 -1.4 29.5 205 15 8 6.3 3.5 | -1.1 30.0 190 11 6 6.8 3.7
12000 -0.5 31.1 205 15 8 6.0 3.3 | -0.1 31.8 190 12 6 6.0 3.3
11750 -0.1 31.8 205 15 8 5.2 2.9 | 0.2 32.4 190 13 7 4.4 2.4
11500 0.3 32.5 200 16 8 5.4 2.9 | 0.6 33.1 195 13 7 4.9 2.7
11250 0.7 33.3 200 16 8 5.8 3.2 | 0.9 33.6 195 14 7 6.1 3.3
11000 1.1 34.0 200 17 9 4.2 2.3 | 1.3 34.3 195 15 7 4.1 2.2
10750 1.3 34.3 200 17 9 2.5 1.4 | 1.5 34.7 195 15 8 1.4 0.8
10500 1.5 34.7 195 17 9 2.5 1.4 | 1.5 34.7 195 16 8 1.2 0.7
10250 1.7 35.1 195 18 9 5.2 2.8 | 1.6 34.9 195 16 8 2.5 1.4
10000 2.1 35.8 190 18 9 4.0 2.2 | 1.8 35.2 190 17 9 2.8 1.5
9750 2.2 36.0 190 18 9 1.2 0.7 | 1.9 35.4 190 18 9 1.9 1.0
9500 2.3 36.1 185 19 10 1.1 0.6 | 2.1 35.8 185 19 10 1.7 0.9
9250 2.4 36.3 185 20 10 4.3 2.4 | 2.2 36.0 185 20 10 2.9 1.6
9000 2.9 37.2 180 20 10 8.1 4.5 | 2.5 36.5 180 21 11 6.3 3.5
8750 3.4 38.1 180 20 11 7.5 4.1 | 3.0 37.4 180 21 11 7.4 4.1
8500 4.0 39.2 175 21 11 7.4 4.1 | 3.5 38.3 175 21 11 7.5 4.1
8250 4.5 40.1 170 21 11 8.6 4.7 | 4.0 39.2 175 21 11 6.2 3.4
8000 5.3 41.5 170 20 10 16.2 8.9 | 4.5 40.1 175 20 11 8.7 4.8
7750 6.9 44.4 170 18 9 24.8 13.6 | 5.4 41.7 170 17 9 16.9 9.3
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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