Weather Forecasts

Daily Weather Summary

July 4, 1999:

Happy 4th of July! High pressure ridge in control from surface up to 500 mb. Air mass is drier aloft, but moisture still remains near surface. Therefore, expect scattered Cu clouds this afternoon, with isolated thunderstorms, like yesterday. High: 93 Low: 72 Mixing Hgt.: 2100 m MSL. 850 mb winds are out of the WSW or SW off the profilers, and that trend should continue, as we are very near the ridge axis. So, wind direction will vary from WSW to S, and the speeds will be light, generally < 7 kts.

Tomorrow's Forecast

July 5, 1999:

Very little change expected. With surface ridge/subsidence, there may be a little less Cu tomorrow than today. High: 95 Low: 73.

Day after Tomorrow Forecast

July 6, 1999:

No big change from Monday. Looking at AVN model, moisture may increase a little as we go into the week, so thunderstorm chances hang in there. High: 93 Low: 73


Basically, southerly flow continues. Surface and 500 mb ridge seem to weaken a little, so afternoon/evening thunderstorm chances continue through the week. Highs: 90-95. Lows: 70-75. Tropical system apparent on satellite pictures off Bahamas is moving WNW. Some of this moisture could impact us as we go into the week, but timing and certainty very low, so we'll just keep watching.

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 the previous evening. The lower image shows particle positions as of the following morning 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