A deep and broad atmospheric trough (produced by a dip in the jet stream) is allowing cool, Canadian air to flow southward. Extending from the Rockies to the East Coast, this trough will bring the first convincing period of autumn for many Americans, especially for those in the Southeast.
Here in central Missouri, we expect our first freeze of the season by midweek and will experience temperatures below average for mid October. Bringing clear skies and relief from the heat, humidity and recurrent storms, it is a welcome development indeed.
In no hurry to leave, the trough is bringing back the October of old and may just nudge migrant waterfowl southward. Time to hit the trails to enjoy the colorful foliage, fresh air and energized wildlife!