Brainstorm Answer: 19th Century Forecasts
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Which one of the following would have not been reported in a standard weather observation prior to 1900? Relative humidity. Visibility. Barometric Pressure. Snow Depth. Minimum Temperature. Hi, I'm Dave Thurlow for the Mount Washington Observatory and that was our most recent Brainstorm question.

Weather observing predates pretty much all mechanical and technological advances in US history. It was back in the late 1700's that Thomas Jefferson inaugurated the first US network of weather observers strewn across 6 of the original colonies. By the beginning of the last century, weather observation had become standardized across the country with a list of meteorological indicators to be eyeballed daily. These included all but one of the following: Relative humidity. Visibility. Barometric Pressure. Snow Depth. Minimum Temperature. So the question was, which one of these that would not have appeared on the weather charts until after 1900.

For the answer, we turn to a listener of WFYI in Indianapolis, IN:

"Hi, this is Kathy Carlson in Franklin, IN and I'm trying to answer the recent Brainstorm. I think the answer is that visibility, number 2, would not have been reported, but hey, what do I know."

Well, don't sell yourself short Kathy because visibility is the answer. Humidity, Pressure, snow depth, minimum temperature all would have been reported. But why not visibility? To explain that, here's Gerald Marburg of Omaha, NE. He listens to KVNO:

"Because prior to that time, it probably never occurred to anybody because people weren't flying yet."

That's right. There were no airplanes before 1900, so weather observers and people in general just didn't care what the visibility was. It just wasn't important.

Be sure to tune in tomorrow, when we have a brand new Weather Notebook Brainstorm.