NOAA’s once-a-decade update of climate averages shows trend toward warmer, wetter weather

Report gets released May 4, 2021
Published: May. 3, 2021 at 8:05 PM EDT
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RICHMOND, Va. (WWBT) - A small, but noticeable change comes to our weather reports every ten years. Starting Tuesday, Richmond’s AVERAGE highs and lows will change. This change will happen for all of the thousands of climate sites across the country.

Click here to read the report’s 30-page briefing

They say if you don’t like the weather, just wait a day and it’ll change. But our climate is changing too. And starting Tuesday, the base set of climate data that you see us use on TV will get an update. Today’s average high low is based on what happened from 1981-2010, but starting Tuesday, and for the next 10 years, the 1980s get dropped and the 2010s get factored in.

This update happens every 10 years and it’s important! Jeremy Hoffman, the Chief Scientist at the Science Museum of Virginia, says the new numbers help all kinds of people keep the economy humming “agricultural decision making, electricity load-bearing, heating requirements for building, and construction scheduling.”

So what’s changing? In general, almost all of the country has gotten warmer, and in the Southeast and Mid-Atlantic, where we live, it’s also gotten wetter. This is a trend that’s been going on since NOAA first came out with this data 100 years ago.

The exceptions: The Southwest (Trending DRY) plus Montana and the Dakotas which are trending cooler than average.

From NOAA report on new Climate Normals
From NOAA report on new Climate Normals(NOAA)

Hidden in the monthly data is that the biggest changes are that winters are warming more than any other season. This means the frost window is shrinking, plus more of our snow is falling as rain in the winter.

The changes are only a degree or less but have a big impact, especially as it continues a trend that started years ago.

Dr. Hoffman says, “a warming atmosphere has more water in it so that can fall as more intense periods of precipitation what this also means there could be longer periods of flash drought between these precipitation events”

Plus a more humid atmosphere means more muggy nights in summer when the temperature stays above 68°.

This warmer, wetter pattern matches up with what climatologists have predicted about how global warming would play out, and it also makes sense anecdotally, by adding in the 2010s to our climate normals, we added in some of the wettest and warmest years on record.

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