394 UXUS97 KBOU 311309 SRGBOU Soaring Forecast National Weather Service Denver/Boulder, Colorado 609 AM MST Monday December 31, 2012 This forecast is for Monday December 31, 2012: If the trigger temperature of 32.0 F/0.0 C is reached...then Thermal Soaring Index....................... Poor Maximum rate of lift........................ 0 ft/min (0.0 m/s) Maximum height of thermals.................. 5742 ft MSL (457 ft AGL) Forecast maximum temperature................... 20.0 F/-7.1 C Time of trigger temperature.................... None Time of overdevelopment........................ None 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................. None Thermal soaring outlook for Tuesday 01/01...... Poor Wave Soaring Index............................. Good Wave Soaring Index trend (to 1700 MST)......... Becoming poor Height of stable layer (12-18K ft MSL)......... 12161 ft MSL (6876 ft AGL) Weak PVA/NVA (through 1700 MST)................ Weak PVA Potential height of wave....................... 18545 ft MSL (13260 ft AGL) Wave soaring outlook for Tuesday 01/01......... Poor Remarks... Areas of snow developing Sunrise/Sunset.................... 07:20:27 / 16:45:19 MST Total possible sunshine........... 9 hr 24 min 52 sec (564 min 52 sec) Altitude of sun at 12:02:49 MST... 27.28 degrees Upper air data from rawinsonde observation taken on 12/31/2012 at 0500 MST Freezing level.................. Entire airmass below 32 F / 0 C Convective condensation level... 14002 ft MSL (8717 ft AGL) Lifted condensation level....... 7669 ft MSL (2383 ft AGL) Lifted index.................... +13.9 K index......................... +10.4 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 -54.4 -65.9 220 32 16 8.0 4.4 111.8 233.3 67.3 M M 45000 -49.4 -56.9 245 46 24 6.3 3.5 95.5 203.9 62.0 M M 40000 -49.4 -56.9 233 55 28 3.6 2.0 71.2 160.1 50.6 M M 38000 -49.7 -57.5 229 59 30 -3.4 -1.9 61.9 143.3 45.7 M M 36000 -50.7 -59.3 227 61 32 -9.2 -5.1 51.7 125.0 40.0 M M 34000 -49.9 -57.8 225 63 33 4.3 2.3 44.3 111.8 35.9 M M 32000 -49.7 -57.5 220 69 35 -13.2 -7.2 36.5 97.7 31.1 M M 30000 -48.2 -54.8 215 64 33 1.7 0.9 30.7 87.2 27.6 M M 29000 -48.8 -55.8 209 61 32 1.9 1.0 25.9 78.6 24.4 M M 28000 -47.7 -53.9 207 60 31 5.9 3.3 23.5 74.3 22.9 M M 27000 -45.5 -49.9 205 56 29 0.6 0.3 21.6 70.8 21.8 M M 26000 -45.6 -50.1 205 41 21 4.2 2.3 17.7 63.9 19.1 M M 25000 -44.2 -47.6 205 27 14 5.7 3.1 15.8 60.4 17.8 M M 24000 -41.7 -43.1 207 24 12 9.0 5.0 15.3 59.5 17.6 M M 23000 -39.0 -38.2 210 22 11 8.7 4.8 15.1 59.1 17.6 M M 22000 -36.4 -33.5 211 22 11 8.9 4.9 14.7 58.4 17.5 M M 21000 -33.7 -28.7 213 23 12 9.1 5.0 14.4 58.0 17.5 M M 20000 -30.9 -23.6 214 23 12 9.2 5.0 14.3 57.7 17.6 M M 19500 -29.7 -21.5 217 24 12 7.7 4.2 14.0 57.1 17.4 M M 19000 -28.5 -19.3 220 25 13 7.8 4.3 13.6 56.5 17.2 M M 18500 -27.4 -17.3 222 27 14 7.8 4.3 13.3 55.9 17.0 M M 18000 -26.2 -15.2 224 28 14 7.8 4.3 13.0 55.4 16.9 M M 17500 -25.1 -13.2 226 25 13 7.7 4.2 12.6 54.7 16.6 M M 17000 -23.9 -11.0 228 22 11 7.7 4.2 12.3 54.1 16.4 M M 16500 -22.8 -9.0 230 19 10 7.7 4.2 12.0 53.5 16.2 M M 16000 -21.6 -6.9 234 16 8 7.7 4.2 11.7 53.0 16.0 M M 15500 -20.5 -4.9 235 12 6 7.7 4.2 11.3 52.4 15.8 M M 15000 -19.4 -2.9 235 8 4 7.7 4.2 11.0 51.8 15.6 M M 14500 -18.2 -0.8 241 7 4 7.7 4.2 10.7 51.2 15.4 M M 14000 -16.5 2.3 250 8 4 7.8 4.3 10.1 50.3 15.0 M M 13500 -15.4 4.3 250 8 4 7.8 4.3 9.8 49.6 14.7 M M 13000 -14.2 6.4 250 7 4 8.4 4.6 9.4 49.0 14.5 M M 12500 -13.5 7.7 250 7 4 0.5 0.3 8.7 47.6 13.8 M M 12000 -13.5 7.7 238 6 3 0.2 0.1 7.1 44.8 12.4 M M 11500 -13.9 7.0 148 8 4 -11.3 -6.2 5.1 41.2 10.7 M M 11000 -14.8 5.4 130 16 8 4.4 2.4 2.5 36.4 8.3 M M 10500 -14.0 6.8 131 15 8 5.3 2.9 1.8 35.2 7.7 M M 10250 -13.6 7.5 132 14 7 5.4 3.0 1.4 34.5 7.4 M M 10000 -13.2 8.2 134 13 7 5.4 2.9 1.1 33.9 7.1 M M 9750 -12.8 9.0 135 13 6 6.1 3.3 0.8 33.4 6.8 M M 9500 -12.4 9.7 140 10 5 6.3 3.5 0.5 32.9 6.5 M M 9250 -11.9 10.6 148 8 4 7.0 3.8 0.2 32.4 6.3 M M 9000 -11.4 11.5 160 6 3 4.3 2.3 -0.0 32.0 6.1 M M 8750 -11.3 11.7 161 3 2 0.1 0.0 -0.7 30.8 5.5 M M 8500 -11.3 11.7 173 1 0 -0.2 -0.1 -1.4 29.4 4.7 M M 8250 -11.2 11.8 330 2 1 4.7 2.6 -2.1 28.3 4.2 M M 8000 -10.6 12.9 335 4 2 8.2 4.5 -2.2 28.0 4.0 M M 7750 -10.1 13.8 341 4 2 7.2 4.0 -2.4 27.6 3.8 M M 7500 -9.5 14.9 347 3 2 7.5 4.1 -2.6 27.3 3.7 M M 7250 -8.9 16.0 355 3 2 7.7 4.2 -2.8 27.0 3.5 M M 7000 -8.4 16.9 004 3 2 7.6 4.2 -2.9 26.7 3.4 M M 6750 -7.8 18.0 046 2 1 8.4 4.6 -3.1 26.4 3.2 M M 6500 -7.3 18.9 083 3 2 3.0 1.7 -3.3 26.1 3.0 M M 6250 -7.3 18.9 101 5 3 0.6 0.3 -4.0 24.7 2.3 M M 6000 -7.3 18.9 109 7 4 -6.2 -3.4 -4.8 23.4 1.5 M M 5750 -8.1 17.4 110 5 2 -7.0 -3.9 -6.3 20.7 0.1 M M 5500 -7.8 18.0 110 2 1 15.4 8.5 -6.7 19.9 -0.4 39 0.2 * * * * * * Numerical weather prediction model forecast data valid * * * * * * 12/31/2012 at 0800 MST | 12/31/2012 at 1100 MST | K index... +6.4 | K index... +5.5 | 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 -54.4 -65.9 250 36 18 2.1 1.2 | -54.1 -65.4 245 36 18 2.3 1.3 45000 -51.3 -60.3 242 44 22 2.1 1.2 | -50.6 -59.1 239 38 20 2.3 1.3 40000 -49.4 -56.9 231 52 27 1.1 0.6 | -48.6 -55.5 240 44 23 1.2 0.7 38000 -48.8 -55.8 227 55 28 0.7 0.4 | -47.9 -54.2 240 46 24 -0.4 -0.2 36000 -48.5 -55.3 228 53 27 0.3 0.2 | -48.0 -54.4 236 44 23 -0.2 -0.1 34000 -48.4 -55.1 229 51 26 0.3 0.2 | -48.2 -54.8 231 43 22 -0.2 -0.1 32000 -49.0 -56.2 225 49 25 -1.6 -0.9 | -48.9 -56.0 225 41 21 -1.7 -0.9 30000 -49.9 -57.8 218 48 25 -1.5 -0.8 | -49.8 -57.6 217 39 20 -1.6 -0.9 29000 -49.8 -57.6 216 48 25 3.3 1.8 | -49.7 -57.5 211 38 20 4.1 2.3 28000 -48.8 -55.8 216 47 24 3.2 1.8 | -48.6 -55.5 203 39 20 3.8 2.1 27000 -47.9 -54.2 215 46 24 3.2 1.8 | -47.4 -53.3 195 40 20 3.8 2.1 26000 -46.8 -52.2 215 45 23 6.9 3.8 | -46.3 -51.3 187 41 21 6.5 3.6 25000 -44.1 -47.4 215 45 23 8.9 4.9 | -43.6 -46.5 194 35 18 8.7 4.8 24000 -41.4 -42.5 215 44 23 8.9 4.9 | -41.0 -41.8 202 30 15 8.7 4.8 23000 -38.8 -37.8 215 43 22 8.3 4.5 | -38.4 -37.1 214 26 13 7.6 4.2 22000 -36.4 -33.5 216 35 18 7.9 4.3 | -36.4 -33.5 220 18 9 6.7 3.7 21000 -34.0 -29.2 218 27 14 7.9 4.3 | -34.4 -29.9 235 11 6 6.7 3.7 20000 -31.6 -24.9 222 20 10 8.5 4.7 | -32.3 -26.1 263 7 4 8.4 4.6 19500 -30.3 -22.5 224 19 10 8.5 4.6 | -30.4 -22.7 272 6 3 8.2 4.5 19000 -28.4 -19.1 229 17 9 8.5 4.6 | -29.2 -20.6 280 5 2 8.2 4.5 18500 -27.2 -17.0 232 15 8 8.5 4.7 | -28.0 -18.4 291 4 2 8.3 4.5 18000 -25.9 -14.6 236 14 7 8.0 4.4 | -26.7 -16.1 304 4 2 8.2 4.5 17500 -24.8 -12.6 238 12 6 7.9 4.3 | -25.5 -13.9 314 4 2 8.2 4.5 17000 -23.6 -10.5 241 11 6 7.9 4.3 | -24.3 -11.7 322 5 2 8.2 4.5 16500 -22.4 -8.3 242 10 5 7.9 4.3 | -23.1 -9.6 328 5 2 8.0 4.4 16000 -21.3 -6.3 244 8 4 7.9 4.3 | -21.9 -7.4 334 5 2 8.2 4.5 15500 -20.1 -4.2 246 8 4 7.9 4.3 | -20.8 -5.4 338 5 3 6.9 3.8 15000 -18.9 -2.0 248 7 4 8.0 4.4 | -19.7 -3.5 339 6 3 7.1 3.9 14500 -17.8 -0.0 249 7 4 7.0 3.9 | -18.7 -1.7 339 6 3 6.0 3.3 14000 -16.8 1.8 248 7 4 7.0 3.8 | -17.9 -0.2 338 7 4 5.9 3.2 13500 -15.8 3.6 249 7 4 5.8 3.2 | -17.1 1.2 338 7 4 4.4 2.4 13000 -15.0 5.0 252 7 3 5.6 3.1 | -16.5 2.3 344 7 4 4.0 2.2 12500 -14.2 6.4 256 6 3 3.5 1.9 | -16.0 3.2 352 7 3 1.4 0.8 12000 -13.8 7.2 264 5 3 2.8 1.5 | -16.0 3.2 007 6 3 0.2 0.1 11500 -13.5 7.7 275 4 2 0.6 0.3 | -15.9 3.4 024 6 3 0.6 0.3 11000 -13.5 7.7 285 2 1 -0.2 -0.1 | -15.8 3.6 040 5 3 0.6 0.3 10500 -13.4 7.9 325 1 0 1.6 0.9 | -15.5 4.1 050 5 3 4.6 2.5 10250 -13.3 8.1 032 1 0 2.2 1.2 | -15.1 4.8 048 5 3 5.4 2.9 10000 -13.1 8.4 071 1 1 1.6 0.9 | -14.7 5.5 046 5 3 5.2 2.8 9750 -13.0 8.6 083 2 1 3.5 1.9 | -14.3 6.3 044 5 3 5.1 2.8 9500 -12.6 9.3 083 2 1 5.8 3.2 | -13.9 7.0 042 5 3 4.9 2.7 9250 -12.1 10.2 082 3 1 5.6 3.1 | -13.5 7.7 040 5 3 5.0 2.7 9000 -11.7 10.9 081 3 2 5.6 3.1 | -13.2 8.2 038 5 3 4.9 2.7 8750 -11.3 11.7 079 3 2 5.0 2.7 | -12.8 9.0 037 5 3 4.3 2.3 8500 -11.0 12.2 072 4 2 4.5 2.5 | -12.5 9.5 036 6 3 4.0 2.2 8250 -10.6 12.9 066 4 2 4.7 2.6 | -12.2 10.0 035 6 3 4.0 2.2 8000 -10.3 13.5 060 4 2 4.4 2.4 | -11.9 10.6 035 7 3 4.3 2.4 7750 -10.0 14.0 051 4 2 4.1 2.2 | -11.6 11.1 034 7 3 4.7 2.6 7500 -9.7 14.5 037 4 2 4.2 2.3 | -11.2 11.8 032 7 3 4.8 2.7 7250 -9.4 15.1 020 3 2 3.9 2.1 | -10.9 12.4 031 6 3 4.0 2.2 7000 -9.1 15.6 011 4 2 3.1 1.7 | -10.7 12.7 029 6 3 2.1 1.1 6750 -8.9 16.0 012 4 2 2.7 1.5 | -10.6 12.9 026 5 3 1.4 0.8 6500 -8.7 16.3 012 5 2 2.9 1.6 | -10.4 13.3 023 5 2 2.0 1.1 6250 -8.6 16.5 014 5 3 -0.1 -0.1 | -10.2 13.6 018 4 2 5.2 2.9 6000 -8.7 16.3 019 5 3 -2.9 -1.6 | -9.7 14.5 011 3 2 7.1 3.9 5750 -8.9 16.0 025 5 3 -0.9 -0.5 | -9.2 15.4 003 3 2 6.8 3.8 5500 -9.1 15.6 031 5 3 -6.1 -3.4 | -8.6 16.5 354 3 1 11.8 6.5 12/31/2012 at 1400 MST | 12/31/2012 at 1700 MST | K index... +7.0 | K index... +6.7 | 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 -54.2 -65.6 244 39 20 2.3 1.3 | -53.8 -64.8 256 37 19 2.3 1.2 45000 -50.8 -59.4 240 44 23 2.3 1.3 | -50.4 -58.7 248 41 21 2.3 1.2 40000 -48.3 -54.9 243 41 21 1.5 0.8 | -47.9 -54.2 241 40 21 1.6 0.9 38000 -47.3 -53.1 245 39 20 -0.0 -0.0 | -47.0 -52.6 238 39 20 -0.8 -0.4 36000 -47.2 -53.0 246 39 20 0.2 0.1 | -47.3 -53.1 241 34 17 -0.5 -0.3 34000 -47.1 -52.8 246 38 20 0.2 0.1 | -47.6 -53.7 245 29 15 -0.5 -0.3 32000 -47.5 -53.5 243 34 18 -0.9 -0.5 | -47.6 -53.7 249 25 13 0.3 0.1 30000 -48.0 -54.4 237 30 15 -0.9 -0.5 | -47.4 -53.3 252 22 11 0.3 0.1 29000 -48.1 -54.6 232 28 14 1.4 0.7 | -47.4 -53.3 252 21 11 -0.2 -0.1 28000 -47.7 -53.9 221 27 14 1.2 0.7 | -47.4 -53.3 247 21 11 -0.2 -0.1 27000 -47.4 -53.3 210 27 14 1.2 0.7 | -47.5 -53.5 242 20 11 -0.2 -0.1 26000 -47.0 -52.6 199 27 14 4.0 2.2 | -47.6 -53.7 237 20 11 3.0 1.6 25000 -44.8 -48.6 208 22 11 7.5 4.1 | -45.3 -49.5 243 17 9 7.8 4.3 24000 -42.5 -44.5 223 17 9 7.5 4.1 | -43.0 -45.4 251 13 7 7.8 4.3 23000 -40.3 -40.5 246 14 7 8.0 4.4 | -40.6 -41.1 265 11 5 8.2 4.5 22000 -37.7 -35.9 250 9 5 8.6 4.7 | -38.0 -36.4 272 8 4 8.6 4.7 21000 -35.2 -31.4 261 5 3 8.6 4.7 | -35.4 -31.7 281 7 3 8.7 4.8 20000 -32.6 -26.7 303 3 1 8.2 4.5 | -32.9 -27.2 295 6 3 8.5 4.7 19500 -30.8 -23.4 310 4 2 8.3 4.5 | -30.9 -23.6 301 8 4 8.6 4.7 19000 -29.5 -21.1 312 5 3 8.3 4.5 | -29.7 -21.5 303 10 5 8.6 4.7 18500 -28.3 -18.9 313 6 3 8.3 4.5 | -28.4 -19.1 305 11 6 8.6 4.7 18000 -27.1 -16.8 314 7 4 8.4 4.6 | -27.1 -16.8 306 12 6 8.4 4.6 17500 -25.8 -14.4 311 7 4 8.5 4.6 | -25.9 -14.6 305 12 6 8.3 4.5 17000 -24.5 -12.1 308 7 4 8.4 4.6 | -24.6 -12.3 304 12 6 8.1 4.4 16500 -23.3 -9.9 309 7 4 7.9 4.4 | -23.5 -10.3 305 12 6 7.0 3.9 16000 -22.1 -7.8 313 6 3 8.1 4.4 | -22.5 -8.5 308 12 6 7.3 4.0 15500 -21.0 -5.8 317 6 3 7.0 3.8 | -21.5 -6.7 314 12 6 5.5 3.0 15000 -20.0 -4.0 320 7 4 7.1 3.9 | -20.7 -5.3 322 13 7 5.6 3.1 14500 -18.9 -2.0 323 8 4 6.7 3.7 | -19.8 -3.6 328 14 7 6.7 3.7 14000 -17.9 -0.2 328 9 5 6.7 3.7 | -18.8 -1.8 332 15 7 6.9 3.8 13500 -17.0 1.4 333 10 5 5.1 2.8 | -17.8 -0.0 336 15 8 5.3 2.9 13000 -16.3 2.7 338 10 5 4.5 2.5 | -17.1 1.2 339 15 8 4.8 2.6 12500 -15.7 3.7 343 9 5 2.1 1.2 | -16.5 2.3 341 15 8 3.2 1.7 12000 -15.6 3.9 351 9 4 0.9 0.5 | -16.1 3.0 346 14 7 2.5 1.3 11500 -15.5 4.1 359 8 4 1.3 0.7 | -15.8 3.6 350 13 7 2.5 1.3 11000 -15.2 4.6 007 8 4 1.4 0.8 | -15.4 4.3 356 12 6 2.3 1.3 10500 -14.9 5.2 013 8 4 3.9 2.1 | -14.9 5.2 001 11 6 5.1 2.8 10250 -14.6 5.7 013 8 4 4.5 2.5 | -14.5 5.9 003 11 6 5.6 3.1 10000 -14.3 6.3 014 8 4 4.4 2.4 | -14.0 6.8 004 11 6 5.7 3.1 9750 -13.9 7.0 014 8 4 4.3 2.4 | -13.6 7.5 006 11 5 4.6 2.5 9500 -13.6 7.5 014 8 4 4.2 2.3 | -13.3 8.1 006 10 5 3.3 1.8 9250 -13.3 8.1 014 8 4 4.2 2.3 | -13.1 8.4 006 10 5 3.5 1.9 9000 -13.0 8.6 013 8 4 4.2 2.3 | -12.8 9.0 006 10 5 3.5 1.9 8750 -12.7 9.1 013 8 4 3.8 2.1 | -12.6 9.3 006 10 5 3.5 1.9 8500 -12.4 9.7 014 8 4 3.6 2.0 | -12.3 9.9 006 9 5 3.5 1.9 8250 -12.1 10.2 015 8 4 3.6 1.9 | -12.0 10.4 006 9 4 3.8 2.1 8000 -11.9 10.6 016 8 4 3.9 2.1 | -11.8 10.8 006 8 4 2.5 1.4 7750 -11.5 11.3 017 7 4 4.3 2.4 | -11.7 10.9 006 7 4 1.2 0.7 7500 -11.2 11.8 018 7 4 4.3 2.4 | -11.6 11.1 005 6 3 1.2 0.6 7250 -10.9 12.4 019 7 3 4.2 2.3 | -11.5 11.3 004 5 3 2.1 1.2 7000 -10.6 12.9 017 6 3 3.9 2.1 | -11.3 11.7 359 4 2 4.4 2.4 6750 -10.4 13.3 011 6 3 3.7 2.0 | -10.9 12.4 350 4 2 5.0 2.8 6500 -10.1 13.8 003 5 3 4.0 2.2 | -10.5 13.1 339 4 2 5.2 2.8 6250 -9.7 14.5 357 5 3 7.9 4.4 | -10.1 13.8 331 3 2 7.9 4.3 6000 -9.0 15.8 356 5 3 10.8 5.9 | -9.4 15.1 330 3 2 9.5 5.2 5750 -8.2 17.2 354 5 2 9.7 5.3 | -8.8 16.2 329 3 2 9.0 5.0 5500 -7.4 18.7 353 5 2 12.7 7.0 | -8.0 17.6 330 3 2 11.1 6.1 ________________________________________________________________________________ This product is issued twice per day, once by approximately 0630 MST/0730 MDT (1330 UTC) and again by approximately 1830 MST/1930 MDT (0130 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 old Stapleton Airport site in Denver, Colorado at North Latitude: 39 deg 46 min 5.016 sec West Longitude: 104 deg 52 min 9.984 sec Elevation: 5285 feet (1611 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: 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