Roll out those hazy days of summer

At the close out our weekly Jet Streaming podcast Nate King Cole signs off with the tune of the Lazy, Hazy, Crazy Days of Summer. The lyrics are very reminiscent of the good old days of life slowing down in the heat of the July sun.

I recollect my numerous years of forecasting the weather in Indianapolis and how often the distinct edge of bellowing cloud tops would be obscured by the summer haze. Surface visibilities would often be no better than three miles on the horizon. If smog was expected to last more than two days we would hoist a precautionary advisory for poor air quality.

Cold fronts seldom penetrated south of the Great Lakes in mid summer. The remaining industrial plants in the Ohio Valley infused particulates into the stagnant air mass. Thus we experienced the lazy and hazy days of summer. Air quality monitoring systems were not nearly as sophisticated as they are today. Application of simple common sense concluded the air was not very healthy, particularly for individuals with respiratory problems.

National air quality

In aviation observations, haze is reported as a visibility restriction when the horizontal view is less than seven miles. When the haze reduces the visibility to three miles or less it is reported on the hourly weather conditions for the observing site. Human activity in metro areas generates the greatest potential for haze and smog.

With the regular passage of cool fronts, air quality has been quite acceptable in the state and the Twin Cities this summer. Today the air seems quite refreshing. But Thursday is likely to be more humid and less comfortable. Enjoy this crazy day of summer and be thankful that cold fronts sweep the air clean on regular occasions in the upper Midwest.

CE