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Soaring Guidance
Issued by NWS Pueblo, CO
Issued by NWS Pueblo, CO
000
UXUS97 KPUB 110956
SRGPUB
SOARING FORECAST
NATIONAL WEATHER SERVICE PUEBLO CO
356 AM MDT TUE JUN 11 2013
EXPERIMENTAL PRODUCT
This forecast is for Tuesday June 11, 2013:
If the trigger temperature of 79.1 F/26.2 C is reached...then
Thermal Soaring Index....................... Good
Maximum rate of lift........................ 2404 ft/min (12.2 m/s)
Maximum height of thermals.................. 30827 ft MSL (23164 ft AGL)
Forecast maximum temperature................... 95.0 F/35.5 C
Time of trigger temperature.................... 0830 MDT
Time of overdevelopment........................ None
Middle/high clouds during soaring window....... None
Surface winds during soaring window............ Between 20 mph and 30 mph
Height of the -3 thermal index................. 23559 ft MSL (15896 ft AGL)
Thermal soaring outlook for Wednesday 06/12.... Excellent
Wave Soaring Index............................. Poor
Wave Soaring Index trend (to 1800 MDT)......... Improving
Height of stable layer (12-18K ft MSL)......... None
Weak PVA/NVA (through 1800 MDT)................ Neither
Potential height of wave....................... 40460 ft MSL (32797 ft AGL)
Wave soaring outlook for Wednesday 06/12....... Fair
Remarks...
Sunrise/Sunset.................... 05:33:23 / 20:24:31 MDT
Total possible sunshine........... 14 hr 51 min 8 sec (891 min 8 sec)
Altitude of sun at 12:59:06 MDT... 74.12 degrees
Upper air data from numerical model forecast valid on 06/11/2013 at 0600 MDT
Freezing level.................. 16709 ft MSL (9046 ft AGL)
Convective condensation level... 23859 ft MSL (16196 ft AGL)
Lifted condensation level....... 25370 ft MSL (17707 ft AGL)
Lifted index.................... -2.6
K index......................... +10.2
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 -62.7 -80.9 213 15 8 1.7 0.9 78.4 173.2 26.0 M M
45000 -59.4 -74.9 229 23 12 3.0 1.6 59.9 139.8 16.0 M M
40000 -54.5 -66.1 236 47 24 5.8 3.2 45.8 114.4 7.4 M M
38000 -51.0 -59.8 235 45 23 5.8 3.2 42.0 107.6 5.0 M M
36000 -47.5 -53.5 233 42 22 5.6 3.1 39.0 102.2 2.9 M M
34000 -43.0 -45.4 234 39 20 7.9 4.4 37.0 98.7 1.5 M M
32000 -38.2 -36.8 234 35 18 8.0 4.4 35.8 96.4 0.6 M M
30000 -33.2 -27.8 233 32 17 8.5 4.7 34.6 94.3 -0.3 2326 11.8
29000 -30.6 -23.1 233 31 16 8.5 4.7 34.2 93.5 -0.7 2220 11.3
28000 -27.4 -17.3 232 30 15 8.7 4.8 33.7 92.7 -1.0 2087 10.6
27000 -24.8 -12.6 231 30 15 8.7 4.8 33.2 91.8 -1.5 1979 10.1
26000 -22.2 -8.0 231 30 15 8.7 4.8 32.8 91.1 -1.8 1871 9.5
25000 -19.6 -3.3 230 30 15 8.4 4.6 32.5 90.6 -2.1 1764 9.0
24000 -17.3 0.9 230 30 16 7.9 4.3 31.8 89.2 -2.8 1663 8.5
23000 -14.9 5.2 230 31 16 7.9 4.3 31.1 88.0 -3.4 1563 7.9
22000 -12.6 9.3 230 31 16 7.9 4.3 30.5 87.0 -3.9 1464 7.4
21000 -10.2 13.6 230 31 16 7.9 4.3 29.8 85.6 -4.6 1364 6.9
20000 -7.9 17.8 229 30 15 7.9 4.3 29.2 84.5 -5.3 1265 6.4
19500 -6.7 19.9 229 30 15 8.0 4.4 28.9 84.0 -5.6 1215 6.2
19000 -5.6 21.9 230 29 15 7.8 4.3 28.6 83.5 -5.9 1166 5.9
18500 -4.4 24.1 231 29 15 7.9 4.3 28.3 82.9 -6.3 1116 5.7
18000 -3.3 26.1 233 29 15 8.1 4.5 28.0 82.3 -6.6 1067 5.4
17500 -2.1 28.2 234 27 14 8.3 4.6 27.7 81.9 -6.9 1015 5.2
17000 -0.8 30.6 234 26 13 8.3 4.6 27.5 81.5 -7.2 964 4.9
16500 0.5 32.9 234 25 13 9.0 5.0 27.3 81.2 -7.4 910 4.6
16000 1.8 35.2 234 24 12 9.0 4.9 27.2 80.9 -7.6 855 4.3
15500 3.1 37.6 234 23 12 9.3 5.1 27.1 80.7 -7.7 800 4.1
15000 4.5 40.1 233 22 11 9.4 5.2 27.0 80.6 -7.8 743 3.8
14500 5.9 42.6 233 21 11 9.5 5.2 27.0 80.6 -7.9 686 3.5
14000 7.4 45.3 233 20 10 9.6 5.3 26.9 80.5 -8.0 629 3.2
13500 8.8 47.8 234 19 10 9.6 5.3 26.9 80.5 -8.0 571 2.9
13000 10.2 50.4 234 18 9 9.5 5.2 26.9 80.4 -8.1 513 2.6
12500 11.6 52.9 234 18 9 9.5 5.2 26.8 80.3 -8.2 456 2.3
12000 13.0 55.4 235 19 10 9.1 5.0 26.8 80.2 -8.3 400 2.0
11750 13.7 56.7 236 19 10 9.1 5.0 26.7 80.1 -8.4 372 1.9
11500 14.4 57.9 238 19 10 9.3 5.1 26.7 80.0 -8.5 344 1.7
11250 15.1 59.2 239 19 10 8.5 4.7 26.6 79.9 -8.5 316 1.6
11000 15.7 60.3 242 19 10 7.4 4.1 26.5 79.6 -8.7 291 1.5
10750 16.3 61.3 246 19 10 7.4 4.1 26.3 79.3 -8.9 266 1.4
10500 16.8 62.2 250 20 10 7.4 4.1 26.1 79.0 -9.1 242 1.2
10250 17.9 64.2 258 20 10 6.9 3.8 25.7 78.3 -9.5 194 1.0
10000 18.4 65.1 263 20 10 6.8 3.7 25.5 77.9 -9.7 171 0.9
9750 19.0 66.2 267 20 10 7.0 3.9 25.3 77.5 -10.0 148 0.8
9500 19.5 67.1 272 20 10 6.3 3.4 25.1 77.1 -10.2 125 0.6
9250 19.9 67.8 274 21 11 5.5 3.0 24.7 76.5 -10.5 105 0.5
9000 20.3 68.5 274 22 11 4.0 2.2 24.4 75.9 -10.9 86 0.4
8750 20.7 69.3 275 23 12 9.0 4.9 24.0 75.3 -11.3 67 0.3
8500 21.1 70.0 275 23 12 -9.3 -5.1 23.7 74.6 -11.7 48 0.2
8250 19.0 66.2 274 20 10 -36.7 -20.1 20.9 69.7 -14.5 103 0.5
8000 16.4 61.5 272 16 8 -27.2 -14.9 17.6 63.7 -17.9 175 0.9
7750 13.7 56.7 268 11 6 -60.2 -33.0 14.3 57.8 -21.3 246 1.3
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 * * * * * *
06/11/2013 at 0900 MDT | 06/11/2013 at 1200 MDT
|
K index... +8.6 | K index... +4.0
|
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 -62.0 -79.6 221 18 10 1.8 1.0 | -61.7 -79.1 214 22 12 2.2 1.2
45000 -59.0 -74.2 228 25 13 2.6 1.4 | -58.3 -72.9 224 33 17 2.2 1.2
40000 -54.7 -66.5 241 43 22 6.1 3.4 | -54.7 -66.5 240 52 27 6.3 3.4
38000 -51.2 -60.2 236 44 23 5.9 3.2 | -51.1 -60.0 236 54 28 6.0 3.3
36000 -47.2 -53.0 231 47 24 5.8 3.2 | -47.1 -52.8 232 57 29 5.9 3.2
34000 -42.8 -45.0 230 44 23 7.5 4.1 | -42.7 -44.9 230 53 27 7.4 4.1
32000 -38.3 -36.9 229 42 21 7.5 4.1 | -38.3 -36.9 227 48 25 7.4 4.1
30000 -33.4 -28.1 226 38 20 8.3 4.6 | -33.5 -28.3 229 44 22 8.0 4.4
29000 -30.9 -23.6 225 37 19 8.3 4.6 | -31.1 -24.0 230 41 21 8.1 4.4
28000 -28.4 -19.1 223 35 18 8.2 4.5 | -28.7 -19.7 231 39 20 8.4 4.6
27000 -26.0 -14.8 222 35 18 8.2 4.5 | -26.1 -15.0 232 40 21 8.7 4.8
26000 -23.6 -10.5 222 35 18 8.2 4.5 | -23.5 -10.3 233 41 21 8.7 4.8
25000 -21.1 -6.0 221 34 18 8.2 4.5 | -20.9 -5.6 234 42 22 8.8 4.8
24000 -18.7 -1.7 221 35 18 8.4 4.6 | -18.4 -1.1 237 43 22 8.3 4.5
23000 -15.6 3.9 222 35 18 8.4 4.6 | -15.3 4.5 240 43 22 8.3 4.6
22000 -13.1 8.4 222 35 18 8.1 4.4 | -12.8 9.0 242 44 23 8.2 4.5
21000 -10.8 12.6 223 35 18 8.0 4.4 | -10.4 13.3 241 43 22 8.2 4.5
20000 -8.4 16.9 225 35 18 8.0 4.4 | -8.0 17.6 241 43 22 8.2 4.5
19500 -7.3 18.9 225 35 18 8.0 4.4 | -6.7 19.9 240 42 22 8.0 4.4
19000 -6.1 21.0 226 35 18 8.1 4.4 | -5.6 21.9 239 42 22 7.1 3.9
18500 -4.9 23.2 227 35 18 8.1 4.4 | -4.6 23.7 237 42 22 7.2 4.0
18000 -3.7 25.3 228 36 18 8.7 4.8 | -3.5 25.7 235 42 22 8.2 4.5
17500 -2.4 27.7 227 35 18 8.9 4.9 | -2.3 27.9 233 41 21 8.5 4.7
17000 -1.1 30.0 227 35 18 9.0 4.9 | -1.0 30.2 231 40 20 8.4 4.6
16500 0.3 32.5 227 35 18 9.3 5.1 | 0.2 32.4 232 38 20 7.8 4.3
16000 1.7 35.1 227 34 17 9.3 5.1 | 1.4 34.5 234 36 19 7.8 4.3
15500 3.0 37.4 228 33 17 8.7 4.8 | 2.6 36.7 236 34 17 8.7 4.7
15000 4.4 39.9 230 32 16 8.7 4.8 | 3.8 38.8 238 29 15 8.8 4.8
14500 5.7 42.3 233 30 16 9.1 5.0 | 5.1 41.2 241 24 13 9.2 5.1
14000 7.1 44.8 236 30 15 9.4 5.1 | 6.6 43.9 241 23 12 9.6 5.3
13500 8.6 47.5 239 30 15 9.3 5.1 | 8.0 46.4 241 21 11 9.7 5.3
13000 9.9 49.8 241 29 15 9.0 4.9 | 9.5 49.1 241 20 10 10.0 5.5
12500 11.3 52.3 243 29 15 9.0 4.9 | 10.9 51.6 241 20 10 10.0 5.5
12000 12.6 54.7 245 28 14 8.2 4.5 | 12.4 54.3 241 20 10 9.6 5.3
11750 13.2 55.8 246 27 14 8.3 4.5 | 13.1 55.6 241 19 10 9.7 5.3
11500 13.9 57.0 247 26 13 8.5 4.6 | 13.8 56.8 241 19 10 9.6 5.3
11250 14.5 58.1 248 25 13 7.6 4.1 | 14.6 58.3 241 19 10 9.9 5.4
11000 15.0 59.0 249 26 13 6.7 3.6 | 15.3 59.5 241 19 10 10.2 5.6
10750 15.5 59.9 251 26 13 6.9 3.8 | 16.1 61.0 241 19 10 10.1 5.5
10500 16.0 60.8 253 26 14 6.7 3.7 | 16.8 62.2 241 18 10 10.1 5.5
10250 16.5 61.7 254 27 14 7.2 3.9 | 17.6 63.7 241 18 9 10.1 5.5
10000 17.1 62.8 254 25 13 7.7 4.2 | 18.3 64.9 241 18 9 10.1 5.5
9750 18.2 64.8 254 21 11 7.7 4.2 | 19.8 67.6 241 18 9 10.1 5.6
9500 18.7 65.7 253 19 10 7.5 4.1 | 20.6 69.1 241 17 9 10.1 5.5
9250 19.3 66.7 255 19 10 7.3 4.0 | 21.3 70.3 241 17 9 9.8 5.4
9000 19.8 67.6 258 18 9 7.6 4.2 | 22.1 71.8 241 17 9 10.3 5.7
8750 20.3 68.5 260 18 9 6.5 3.6 | 22.8 73.0 241 17 9 8.6 4.7
8500 20.8 69.4 262 17 9 11.1 6.1 | 23.6 74.5 241 16 8 15.1 8.3
8250 21.9 71.4 262 15 8 16.7 9.1 | 25.1 77.2 241 15 8 23.5 12.9
8000 23.0 73.4 262 12 6 12.5 6.9 | 26.6 79.9 241 14 7 18.1 9.9
7750 24.1 75.4 261 10 5 24.1 13.2 | 28.2 82.8 242 13 7 33.7 18.5
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
06/11/2013 at 1500 MDT | 06/11/2013 at 1800 MDT
|
K index... +10.4 | K index... +11.0
|
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 -61.1 -78.0 235 30 15 2.6 1.4 | -62.0 -79.6 251 31 16 2.5 1.4
45000 -57.5 -71.5 236 44 23 1.7 0.9 | -58.2 -72.8 257 49 25 2.5 1.4
40000 -54.5 -66.1 241 54 28 6.5 3.6 | -54.1 -65.4 257 59 30 6.5 3.6
38000 -50.8 -59.4 239 55 28 6.1 3.4 | -50.4 -58.7 257 56 29 6.2 3.4
36000 -46.7 -52.1 237 56 29 6.0 3.3 | -46.2 -51.2 256 53 27 6.1 3.4
34000 -42.7 -44.9 239 54 28 6.9 3.8 | -42.1 -43.8 261 51 26 7.0 3.8
32000 -38.5 -37.3 241 52 27 6.9 3.8 | -37.9 -36.2 267 50 26 7.0 3.8
30000 -33.9 -29.0 242 49 25 8.0 4.4 | -33.5 -28.3 269 48 25 7.4 4.0
29000 -31.5 -24.7 242 48 24 8.0 4.4 | -31.3 -24.3 270 46 24 7.4 4.0
28000 -29.1 -20.4 242 46 24 8.4 4.6 | -29.2 -20.6 271 44 23 8.0 4.4
27000 -26.5 -15.7 244 46 24 8.8 4.8 | -26.6 -15.9 270 42 22 8.6 4.7
26000 -23.9 -11.0 246 47 24 8.8 4.8 | -24.0 -11.2 269 40 20 8.6 4.7
25000 -21.3 -6.3 247 47 24 8.8 4.8 | -21.4 -6.5 268 37 19 8.6 4.7
24000 -18.7 -1.7 247 46 24 8.8 4.8 | -18.8 -1.8 267 37 19 9.1 5.0
23000 -15.4 4.3 246 45 23 8.8 4.8 | -15.4 4.3 265 38 20 9.1 5.0
22000 -12.7 9.1 245 44 23 7.9 4.3 | -12.7 9.1 263 39 20 8.0 4.4
21000 -10.5 13.1 246 41 21 7.3 4.0 | -10.5 13.1 259 37 19 7.5 4.1
20000 -8.4 16.9 247 38 19 7.3 4.0 | -8.3 17.1 255 36 18 7.6 4.1
19500 -7.3 18.9 247 36 19 7.4 4.1 | -7.2 19.0 253 35 18 7.6 4.2
19000 -6.2 20.8 247 32 17 7.9 4.3 | -6.0 21.2 251 34 17 8.2 4.5
18500 -5.0 23.0 246 28 14 7.9 4.4 | -4.8 23.4 250 32 16 8.2 4.5
18000 -3.9 25.0 244 24 12 9.1 5.0 | -3.6 25.5 249 30 15 8.9 4.9
17500 -2.4 27.7 244 24 12 9.6 5.3 | -2.3 27.9 249 29 15 9.2 5.1
17000 -1.0 30.2 244 24 12 9.7 5.3 | -0.9 30.4 249 27 14 9.2 5.1
16500 0.5 32.9 243 24 12 9.8 5.4 | 0.5 32.9 249 26 13 9.2 5.1
16000 1.9 35.4 243 23 12 9.8 5.4 | 1.8 35.2 250 25 13 9.2 5.1
15500 3.4 38.1 242 23 12 9.9 5.4 | 3.2 37.8 251 24 12 9.5 5.2
15000 4.9 40.8 241 22 12 9.9 5.4 | 4.6 40.3 253 24 12 9.6 5.3
14500 6.3 43.3 240 22 11 9.9 5.4 | 6.0 42.8 255 23 12 9.4 5.2
14000 7.8 46.0 239 22 11 9.9 5.4 | 7.4 45.3 257 23 12 9.2 5.0
13500 9.3 48.7 238 21 11 9.9 5.4 | 8.8 47.8 260 22 11 9.3 5.1
13000 10.7 51.3 238 21 11 9.8 5.4 | 10.2 50.4 261 22 11 10.0 5.5
12500 12.2 54.0 237 20 11 9.8 5.4 | 11.7 53.1 262 22 11 10.0 5.5
12000 13.7 56.7 236 20 10 9.7 5.3 | 13.2 55.8 262 22 11 9.6 5.3
11750 14.4 57.9 236 20 10 9.7 5.3 | 13.9 57.0 263 21 11 9.7 5.3
11500 15.1 59.2 235 20 10 9.6 5.3 | 14.6 58.3 263 21 11 9.6 5.3
11250 15.8 60.4 235 20 10 9.8 5.4 | 15.3 59.5 263 21 11 9.7 5.3
11000 16.6 61.9 234 20 10 10.1 5.5 | 16.1 61.0 264 21 11 9.9 5.4
10750 17.3 63.1 234 19 10 10.0 5.5 | 16.8 62.2 264 21 11 9.9 5.4
10500 18.1 64.6 234 19 10 10.1 5.5 | 17.5 63.5 265 21 11 9.8 5.4
10250 18.8 65.8 233 19 10 10.0 5.5 | 18.3 64.9 265 21 11 10.0 5.5
10000 19.6 67.3 233 19 10 10.0 5.5 | 19.0 66.2 266 21 11 10.1 5.6
9750 21.1 70.0 232 18 9 10.0 5.5 | 20.5 68.9 266 20 11 10.2 5.6
9500 21.8 71.2 232 18 9 10.1 5.5 | 21.3 70.3 267 20 10 10.1 5.5
9250 22.6 72.7 231 18 9 10.1 5.5 | 22.0 71.6 267 20 10 9.8 5.4
9000 23.3 73.9 231 18 9 10.5 5.7 | 22.8 73.0 268 20 10 10.0 5.5
8750 24.1 75.4 231 17 9 9.2 5.1 | 23.5 74.3 269 19 10 9.4 5.1
8500 24.8 76.6 230 17 9 13.8 7.6 | 24.2 75.6 269 19 10 11.6 6.4
8250 26.2 79.2 230 16 8 21.5 11.8 | 25.2 77.4 270 18 9 15.0 8.3
8000 27.7 81.9 229 15 8 20.3 11.1 | 26.3 79.3 270 16 8 14.2 7.8
7750 29.3 84.7 229 13 7 26.7 14.6 | 27.4 81.3 270 14 7 17.8 9.8
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 one per day 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 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.
At this time, the output from this considered experimental.
DEFINITIONS:
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 - 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, cirrostatus, 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.
071806
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