Friday, February 24, 2017

The U.S. Is Poised to Set a Record-Setting Record

Record highs are outpacing record lows in February 2017 at a record-setting pace. (Credit: Click to Enlarge.
Unseasonable warmth has kickstarted spring up to a month early in the Southeast, cut into already paltry Great Lakes ice cover, and created skiing conditions more reminiscent of April in the Northeast.  But the most outstanding aspect of the persistent February warmth is what it has done to the ratio of record highs to record lows.

There have been 3,146 record highs set for the month-to-date compared to only 27 record lows, ensuring February will go down as the 27th month in a row with more highs than lows.  The astonishing 116-to-1 ratio of highs to lows would easily set a record for the most lopsided monthly ratio in history.  There have also been 248 monthly record highs and no monthly record lows.

“If the eventual ratio is above 50-to-1 this would be historic,” Guy Walton, a meteorologist who tracks record temperatures, said.

The increasing ratio of record highs vs. record lows is one of the hallmarks of climate change.  By raising the baseline temperature, climate change has made it more likely for record highs to be set while decreasing the odds of record lows.  In a world that wasn’t warming, that ratio would remain constant right around 1-to-1, but research has shown that hasn’t been the case with highs outpacing lows more and more with each passing decade.

The trend is expected to continue into the future.  By mid-century, the ratio could be as high as 15-to-1 in any given year unless carbon pollution is curtailed.

There has been a huge geographical spread of warm and downright hot weather stretching across the U.S.  The latest bout of warm weather has seen Milwaukee reach 71°F, Madison hit 68°F, and Green Bay crack 65°F on Wednesday.  All are February records and about 30°F above normal for this time of year.
More daily records are in danger of falling across the Northeast for the latter half of the week as warm weather continues its march across the country. On the Texas-Mexico border, it’s possible temperatures could crack 100°F on Thursday.

This year’s freakish February numbers only tell part of the story. The warm weather has acted like a time machine, turning the clock more than a month forward in places.

In the Southeast, locations are seeing spring arrive up to four weeks early, according to the U.S. National Phenology Network spring leaf index. Spring coming earlier is another hallmark of climate change.

“I can only say how things are shaping up so far, but so far, it’s shockingly early,” Theresa Crimmins, the assistant director of the network, said. “Eastern redbuds have been reported with open flowers in mid-February this year in North Carolina. In the previous three years, they haven’t been reported to have open flowers until March or April. I could go on and on. There are lots of reports of remarkably early phenology flooding in. The signature of the really early spring that we see in the spring index is definitely driven by temperature.”

Read more at The U.S. Is Poised to Set a Record-Setting Record

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