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Soaring Guidance
Issued by NWS Pueblo, CO
Issued by NWS Pueblo, CO
000 UXUS97 KPUB 120941 SRGPUB SOARING FORECAST NATIONAL WEATHER SERVICE PUEBLO CO 341 AM MDT WED JUN 12 2013 EXPERIMENTAL PRODUCT This forecast is for Wednesday June 12, 2013: If the trigger temperature of 72.6 F/22.5 C is reached...then Thermal Soaring Index....................... Excellent Maximum rate of lift........................ 1848 ft/min (9.4 m/s) Maximum height of thermals.................. 26303 ft MSL (18640 ft AGL) Forecast maximum temperature................... 89.0 F/32.1 C Time of trigger temperature.................... 0815 MDT Time of overdevelopment........................ None Middle/high clouds during soaring window....... None Surface winds during soaring window............ 20 mph or less Height of the -3 thermal index................. 20907 ft MSL (13244 ft AGL) Thermal soaring outlook for Thursday 06/13..... Excellent Wave Soaring Index............................. Poor Wave Soaring Index trend (to 1800 MDT)......... No change Height of stable layer (12-18K ft MSL)......... None Weak PVA/NVA (through 1800 MDT)................ Weak PVA Potential height of wave....................... 40305 ft MSL (32642 ft AGL) Wave soaring outlook for Thursday 06/13........ Poor Remarks... Sunrise/Sunset.................... 05:33:19 / 20:24:59 MDT Total possible sunshine........... 14 hr 51 min 40 sec (891 min 40 sec) Altitude of sun at 12:59:18 MDT... 74.18 degrees Upper air data from numerical model forecast valid on 06/12/2013 at 0600 MDT Freezing level.................. 16171 ft MSL (8508 ft AGL) Convective condensation level... 22308 ft MSL (14645 ft AGL) Lifted condensation level....... 23584 ft MSL (15921 ft AGL) Lifted index.................... -2.4 K index......................... +1.0 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 -62.4 -80.3 252 28 15 3.0 1.6 78.6 173.5 28.1 M M 45000 -58.4 -73.1 267 36 19 1.9 1.0 62.5 144.5 19.7 M M 40000 -55.1 -67.2 276 56 29 6.4 3.5 46.0 114.7 9.8 M M 38000 -51.4 -60.5 275 56 29 6.2 3.4 42.5 108.5 7.6 M M 36000 -47.3 -53.1 274 57 29 6.1 3.3 39.5 103.0 5.6 M M 34000 -42.5 -44.5 272 52 27 8.1 4.5 37.7 99.9 4.5 M M 32000 -37.7 -35.9 269 47 24 8.2 4.5 36.7 98.0 3.8 M M 30000 -33.1 -27.6 266 44 23 7.7 4.2 35.0 95.0 2.5 M M 29000 -30.8 -23.4 265 43 22 7.7 4.2 34.2 93.6 2.0 M M 28000 -28.5 -19.3 264 42 21 7.4 4.0 33.6 92.5 1.5 M M 27000 -26.4 -15.5 264 41 21 7.1 3.9 32.5 90.5 0.6 M M 26000 -24.2 -11.6 264 40 21 7.1 3.9 31.5 88.7 -0.2 1826 9.3 25000 -22.1 -7.8 265 39 20 7.1 3.9 30.7 87.2 -0.9 1732 8.8 24000 -19.7 -3.5 264 39 20 8.2 4.5 30.0 86.0 -1.5 1631 8.3 23000 -16.6 2.1 264 39 20 8.2 4.5 29.3 84.7 -2.1 1502 7.6 22000 -14.2 6.4 264 39 20 8.3 4.6 28.9 83.9 -2.5 1399 7.1 21000 -11.6 11.1 265 38 20 8.4 4.6 28.3 82.9 -3.0 1294 6.6 20000 -9.1 15.6 265 38 19 8.4 4.6 27.9 82.1 -3.4 1190 6.0 19500 -7.9 17.8 266 37 19 8.3 4.6 27.7 81.8 -3.6 1137 5.8 19000 -6.7 19.9 264 36 18 8.1 4.4 27.4 81.3 -3.9 1087 5.5 18500 -5.5 22.1 263 34 18 8.1 4.4 27.1 80.8 -4.2 1036 5.3 18000 -4.3 24.3 261 32 17 8.0 4.4 26.8 80.3 -4.5 986 5.0 17500 -3.1 26.4 260 30 16 8.0 4.4 26.5 79.7 -4.8 936 4.8 17000 -2.0 28.4 259 29 15 8.0 4.4 26.2 79.2 -5.1 886 4.5 16500 -0.8 30.6 258 27 14 8.1 4.4 25.9 78.7 -5.4 836 4.2 16000 0.4 32.7 258 25 13 8.2 4.5 25.7 78.2 -5.7 786 4.0 15500 1.5 34.7 258 24 12 7.5 4.1 25.4 77.7 -6.1 737 3.7 15000 2.6 36.7 260 22 12 7.5 4.1 25.0 77.0 -6.5 689 3.5 14500 3.7 38.7 262 21 11 7.8 4.3 24.7 76.4 -6.8 641 3.3 14000 4.9 40.8 264 20 10 8.0 4.4 24.4 75.9 -7.2 592 3.0 13500 6.1 43.0 266 19 10 8.3 4.5 24.1 75.4 -7.5 543 2.8 13000 7.3 45.1 267 16 8 8.7 4.8 23.9 75.1 -7.7 489 2.5 12500 8.6 47.5 268 14 7 8.4 4.6 23.8 74.8 -7.9 436 2.2 12000 9.7 49.5 274 11 5 6.7 3.7 23.4 74.1 -8.4 389 2.0 11750 10.2 50.4 279 9 5 6.9 3.8 23.2 73.7 -8.6 366 1.9 11500 10.7 51.3 286 8 4 6.7 3.7 22.9 73.3 -8.8 343 1.7 11250 11.2 52.2 297 7 4 5.7 3.1 22.7 72.8 -9.1 322 1.6 11000 11.6 52.9 313 7 4 5.0 2.8 22.3 72.2 -9.5 303 1.5 10750 12.0 53.6 329 8 4 5.2 2.9 22.0 71.5 -9.8 284 1.4 10500 12.4 54.3 341 9 4 5.2 2.8 21.6 70.9 -10.2 265 1.3 10250 12.8 55.0 351 10 5 5.9 3.2 21.3 70.3 -10.6 246 1.2 10000 13.2 55.8 358 12 6 6.3 3.5 21.0 69.8 -10.9 225 1.1 9750 13.7 56.7 004 14 7 6.2 3.4 20.7 69.3 -11.2 204 1.0 9500 14.6 58.3 010 18 9 6.5 3.6 20.2 68.4 -11.8 161 0.8 9250 15.1 59.2 011 19 10 6.3 3.5 20.0 67.9 -12.0 139 0.7 9000 15.6 60.1 012 20 10 7.4 4.1 19.7 67.5 -12.3 117 0.6 8750 16.0 60.8 013 20 11 3.2 1.8 19.5 67.1 -12.6 95 0.5 8500 15.8 60.4 010 19 10 -9.1 -5.0 18.5 65.4 -13.6 95 0.5 8250 14.8 58.6 003 14 7 -14.8 -8.1 16.8 62.3 -15.3 117 0.6 8000 13.8 56.8 350 10 5 -10.8 -5.9 15.1 59.2 -17.1 140 0.7 7750 12.8 55.0 325 8 4 -20.9 -11.5 13.4 56.1 -18.8 162 0.8 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 * * * * * * 06/12/2013 at 0900 MDT | 06/12/2013 at 1200 MDT | K index... -1.4 | K index... +3.6 | 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 -62.9 -81.2 253 28 14 2.3 1.2 | -62.6 -80.7 249 24 13 2.3 1.3 45000 -59.6 -75.3 261 34 18 2.1 1.1 | -59.6 -75.3 250 35 18 1.3 0.7 40000 -55.9 -68.6 272 50 26 7.3 4.0 | -56.7 -70.1 260 49 25 8.1 4.4 38000 -51.6 -60.9 272 48 25 7.2 4.0 | -51.9 -61.4 264 46 23 8.1 4.4 36000 -46.7 -52.1 272 47 24 7.3 4.0 | -46.4 -51.5 269 42 22 8.1 4.5 34000 -42.0 -43.6 269 43 22 8.0 4.4 | -41.4 -42.5 271 42 21 8.4 4.6 32000 -37.2 -35.0 266 40 20 8.1 4.5 | -36.4 -33.5 273 42 21 8.7 4.8 30000 -32.8 -27.0 269 38 19 7.3 4.0 | -32.4 -26.3 274 40 21 6.4 3.5 29000 -30.6 -23.1 272 37 19 7.3 4.0 | -30.5 -22.9 274 39 20 6.4 3.5 28000 -28.4 -19.1 274 36 18 7.0 3.8 | -28.5 -19.3 274 38 20 7.7 4.2 27000 -26.4 -15.5 275 36 18 6.9 3.8 | -26.1 -15.0 270 36 19 8.0 4.4 26000 -24.3 -11.7 276 36 18 6.9 3.8 | -23.7 -10.7 266 34 17 8.0 4.4 25000 -22.3 -8.1 276 36 18 7.0 3.9 | -21.3 -6.3 262 32 16 8.1 4.5 24000 -19.7 -3.5 274 35 18 8.9 4.9 | -18.8 -1.8 260 32 16 8.6 4.7 23000 -16.4 2.5 271 35 18 8.9 4.9 | -15.6 3.9 258 32 16 8.6 4.7 22000 -13.8 7.2 268 34 18 8.9 4.9 | -13.1 8.4 256 32 17 8.7 4.8 21000 -11.1 12.0 265 35 18 9.0 4.9 | -10.4 13.3 255 34 18 8.7 4.8 20000 -8.4 16.9 262 36 19 9.0 4.9 | -7.8 18.0 255 36 19 8.7 4.8 19500 -7.0 19.4 261 37 19 8.8 4.9 | -6.5 20.3 254 37 19 8.5 4.6 19000 -5.7 21.7 260 37 19 8.6 4.7 | -5.3 22.5 255 36 19 8.1 4.4 18500 -4.4 24.1 259 37 19 8.6 4.7 | -4.1 24.6 255 36 19 8.2 4.5 18000 -3.2 26.2 259 37 19 8.5 4.6 | -3.0 26.6 256 35 18 6.9 3.8 17500 -1.9 28.6 260 36 18 8.4 4.6 | -2.0 28.4 256 34 17 6.8 3.7 17000 -0.7 30.7 260 35 18 7.7 4.2 | -1.0 30.2 257 32 17 6.6 3.6 16500 0.3 32.5 261 33 17 6.3 3.4 | -0.0 32.0 255 31 16 6.3 3.5 16000 1.2 34.2 261 31 16 6.1 3.3 | 0.9 33.6 253 30 15 6.2 3.4 15500 2.3 36.1 260 29 15 8.1 4.4 | 1.9 35.4 249 28 14 8.3 4.5 15000 3.4 38.1 259 27 14 8.0 4.4 | 3.1 37.6 245 26 13 8.1 4.5 14500 4.6 40.3 257 24 13 7.6 4.2 | 4.2 39.6 239 24 12 7.9 4.4 14000 5.6 42.1 251 21 11 7.5 4.1 | 5.4 41.7 235 23 12 7.9 4.3 13500 6.7 44.1 242 19 10 7.5 4.1 | 6.5 43.7 231 21 11 7.4 4.1 13000 7.8 46.0 234 18 9 7.4 4.1 | 7.5 45.5 224 19 10 7.0 3.8 12500 8.9 48.0 225 17 9 7.5 4.1 | 8.5 47.3 215 17 9 6.7 3.7 12000 10.0 50.0 222 16 8 7.9 4.3 | 9.4 48.9 202 14 7 6.0 3.3 11750 10.6 51.1 221 16 8 8.1 4.4 | 9.8 49.6 194 12 6 5.9 3.2 11500 11.2 52.2 219 15 8 7.3 4.0 | 10.2 50.4 183 11 6 6.7 3.7 11250 11.6 52.9 220 14 7 4.5 2.5 | 10.8 51.4 177 11 6 8.9 4.9 11000 11.9 53.4 223 12 6 3.1 1.7 | 11.5 52.7 175 11 6 9.7 5.3 10750 12.1 53.8 227 9 5 3.5 1.9 | 12.2 54.0 174 11 6 9.4 5.2 10500 12.4 54.3 234 7 4 3.4 1.9 | 12.9 55.2 172 11 6 9.6 5.3 10250 12.6 54.7 245 5 3 3.3 1.8 | 13.6 56.5 170 11 6 10.0 5.5 10000 12.8 55.0 264 4 2 3.3 1.8 | 14.4 57.9 169 11 6 10.2 5.6 9750 13.0 55.4 304 3 1 3.1 1.7 | 15.2 59.4 168 11 6 10.1 5.5 9500 13.6 56.5 358 5 2 6.9 3.8 | 16.7 62.1 165 11 6 10.3 5.7 9250 14.2 57.6 002 5 3 8.4 4.6 | 17.5 63.5 164 11 6 10.6 5.8 9000 14.7 58.5 005 6 3 7.5 4.1 | 18.2 64.8 163 11 6 9.8 5.4 8750 15.3 59.5 008 6 3 9.8 5.4 | 19.0 66.2 162 11 6 12.5 6.9 8500 16.2 61.2 009 6 3 14.1 7.7 | 20.1 68.2 160 11 6 17.5 9.6 8250 17.3 63.1 009 5 3 15.2 8.3 | 21.5 70.7 158 11 6 18.6 10.2 8000 18.3 64.9 009 5 2 14.5 8.0 | 22.8 73.0 155 11 6 18.0 9.9 7750 19.4 66.9 009 4 2 16.1 8.8 | 24.1 75.4 153 11 6 19.3 10.6 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 06/12/2013 at 1500 MDT | 06/12/2013 at 1800 MDT | K index... +16.0 | K index... +20.6 | 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 -62.5 -80.5 250 20 10 2.2 1.2 | -63.1 -81.6 242 22 11 1.7 0.9 45000 -59.6 -75.3 253 34 18 1.3 0.7 | -60.4 -76.7 257 34 18 2.3 1.3 40000 -56.8 -70.2 263 48 25 8.0 4.4 | -56.1 -69.0 268 49 25 7.5 4.1 38000 -52.0 -61.6 264 47 24 8.0 4.4 | -51.6 -60.9 267 48 25 7.6 4.2 36000 -46.6 -51.9 265 46 24 8.1 4.4 | -46.5 -51.7 265 47 24 7.8 4.3 34000 -41.6 -42.9 267 43 22 8.3 4.6 | -41.5 -42.7 264 44 23 8.3 4.6 32000 -36.6 -33.9 269 40 21 8.5 4.7 | -36.6 -33.9 263 41 21 8.4 4.6 30000 -32.2 -26.0 269 40 20 7.3 4.0 | -32.0 -25.6 264 40 21 7.5 4.1 29000 -30.1 -22.2 268 40 20 7.3 4.0 | -29.8 -21.6 264 40 20 7.5 4.1 28000 -27.9 -18.2 267 40 20 7.8 4.3 | -27.5 -17.5 265 40 20 7.9 4.4 27000 -25.5 -13.9 264 39 20 7.9 4.4 | -25.1 -13.2 263 40 21 8.0 4.4 26000 -23.1 -9.6 260 39 20 8.0 4.4 | -22.8 -9.0 261 40 21 8.0 4.4 25000 -20.8 -5.4 256 39 20 8.1 4.5 | -20.4 -4.7 260 40 21 8.0 4.4 24000 -18.2 -0.8 254 39 20 8.7 4.8 | -18.1 -0.6 259 40 20 7.8 4.3 23000 -14.9 5.2 252 38 20 8.7 4.8 | -15.2 4.6 257 38 20 7.8 4.3 22000 -12.4 9.7 251 38 20 7.5 4.1 | -12.9 8.8 256 37 19 7.3 4.0 21000 -10.2 13.6 254 38 20 7.4 4.1 | -10.8 12.6 256 32 17 7.3 4.0 20000 -8.0 17.6 258 38 20 7.4 4.1 | -8.6 16.5 256 28 14 7.4 4.0 19500 -6.9 19.6 260 38 20 7.1 3.9 | -7.6 18.3 256 25 13 7.9 4.3 19000 -5.9 21.4 259 35 18 6.7 3.7 | -6.3 20.7 255 23 12 8.6 4.7 18500 -5.0 23.0 258 32 17 6.7 3.7 | -5.1 22.8 254 22 11 8.5 4.7 18000 -3.9 25.0 256 29 15 8.1 4.5 | -3.7 25.3 254 20 10 10.0 5.5 17500 -2.7 27.1 255 27 14 8.2 4.5 | -2.3 27.9 254 20 10 10.0 5.5 17000 -1.6 29.1 253 25 13 8.4 4.6 | -0.8 30.6 253 20 10 9.8 5.4 16500 -0.3 31.5 251 23 12 8.7 4.8 | 0.6 33.1 253 19 10 9.6 5.2 16000 1.0 33.8 250 22 11 8.7 4.8 | 2.1 35.8 252 19 10 9.6 5.2 15500 2.3 36.1 249 21 11 9.2 5.1 | 3.5 38.3 250 19 10 9.7 5.3 15000 3.7 38.7 247 20 10 9.2 5.0 | 4.9 40.8 248 18 10 9.7 5.3 14500 5.0 41.0 245 18 10 8.9 4.9 | 6.4 43.5 245 18 9 9.3 5.1 14000 6.3 43.3 241 17 9 8.8 4.8 | 7.7 45.9 241 18 9 9.2 5.0 13500 7.6 45.7 237 16 8 8.6 4.7 | 9.1 48.4 237 17 9 8.9 4.9 13000 8.8 47.8 228 16 8 8.3 4.5 | 10.3 50.5 229 17 9 8.6 4.7 12500 10.1 50.2 220 15 8 8.1 4.4 | 11.6 52.9 221 17 9 8.3 4.5 12000 11.2 52.2 207 15 8 7.6 4.2 | 12.7 54.9 213 18 9 7.4 4.1 11750 11.7 53.1 201 16 8 7.5 4.1 | 13.3 55.9 209 18 9 7.4 4.1 11500 12.3 54.1 195 16 8 7.8 4.3 | 13.8 56.8 206 19 10 7.5 4.1 11250 12.9 55.2 190 16 8 8.9 4.9 | 14.4 57.9 202 19 10 7.7 4.2 11000 13.6 56.5 188 16 8 9.4 5.1 | 15.0 59.0 199 20 10 7.9 4.3 10750 14.3 57.7 186 17 9 9.2 5.1 | 15.5 59.9 195 20 10 7.8 4.3 10500 15.0 59.0 184 17 9 9.4 5.1 | 16.1 61.0 191 20 10 8.0 4.4 10250 15.7 60.3 183 17 9 9.9 5.4 | 16.8 62.2 189 20 10 9.3 5.1 10000 16.4 61.5 182 17 9 10.2 5.6 | 17.5 63.5 187 20 10 10.1 5.6 9750 17.2 63.0 181 17 9 10.1 5.5 | 18.2 64.8 186 20 10 9.9 5.4 9500 18.7 65.7 179 17 9 10.6 5.8 | 19.7 67.5 183 20 10 10.0 5.5 9250 19.5 67.1 179 17 9 10.9 6.0 | 20.4 68.7 182 20 10 10.1 5.6 9000 20.3 68.5 178 17 9 10.4 5.7 | 21.2 70.2 181 20 10 10.0 5.5 8750 21.1 70.0 177 17 9 12.1 6.6 | 21.9 71.4 181 20 10 10.5 5.8 8500 22.2 72.0 176 16 8 17.0 9.3 | 22.8 73.0 179 19 10 12.8 7.0 8250 23.6 74.5 173 15 8 19.2 10.6 | 23.8 74.8 177 17 9 14.1 7.7 8000 24.9 76.8 171 15 7 17.7 9.7 | 24.8 76.6 175 16 8 13.2 7.2 7750 26.3 79.3 167 14 7 21.7 11.9 | 25.8 78.4 171 14 7 15.7 8.6 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 ________________________________________________________________________________ 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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- Page last modified: Jun 3rd, 2013 13:59 UTC