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Weather Forecasts

Daily Weather Summary

June 20, 1999:

Scattered Cu clouds will continue this afternoon, probably being more numerous in western TN due to higher moisture there. A few high Ci clouds will also drift across the region. High: 86 Low: 64 Mixing hgt.: around 2300 m MSL.

Tomorrow's Forecast

June 21, 1999:

A weak 500 mb vorticity max will spin over central Alabama on Monday, but due to limited moisture in Tennessee, the proximity of the vort max will only bring a small chance for showers on Monday. Expect scattered Cu clouds during the afternoon. High: 86 Low: 66 Max Mixing Hgt.: 2300 m MSL. Afternoon 850 mb winds will be light, primarily out of the NE or E, at around 5 kts. A cold air damming event occurring today over the Carolinas may nudge into middle TN tomorrow, picking up the winds to around 10 kts, but this is highly unlikely.

Day after Tomorrow Forecast

June 22, 1999:

The AVN model brings a strong 500 mb shortwave trough/vort max toward central TN on Tuesday, but with 48 hr ETA model valid 12Z Tuesday showing 500 mb ridging to our west, feel that AVN is overdone in bringing trough roaring into TN. So will only mention a chance for mainly afternoon showers or thunderstorms. High: 88 Low: 68.

Outlook

June 23 - 25, 1999:

300 mb trough finally passes by Tuesday, with a ridge over TN by Friday, with jet stream staying to our north. Southerly flow at 850 mb will bring in warmer and more moist Gulf of Mexico air during this period, but the winds will be light, <5 kts. Surface high pressure should be in place by Friday. With this more summer like pattern, afternoon thundershowers are possible, but should be scattered in nature. Highs: 85-90. Lows: lower 70s, with partly cloudy skies.

Profiler Plume Depiction

The following shows a depiction of plume locations as predicted by the profiler winds assimilated into a one-dimensional boundary layer model. The top image shows particle positions as of 8:00 PM CDT for particle releases beginning at 12:00 Noon. The lower image shows particle positions at 7:00 AM CDT for particles released beginning the previous noon.

Forecast Plumes

The following gives a depiction of plume locations using a Lagranagian Particle Model coupled to the Regional Spectral Model. The RSM is run daily in a forecast mode at TVA Muscle Shoals, Alabama.

Plume based on 00z initial fields (mpg file optimized for QuickTime)

Plume based on 12z initial fields (mpg file optimized for QuickTime)

ARL Hysplit Trajectories

Nashville Soundings