Roller-coaster May brought a different season every week

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COLUMBUS (WCMH) — We woke up this morning on the first day of meteorological summer to unseasonably chilly readings in the upper 30s and low 40s on June 1. The Columbus low of 42 degrees narrowly missed the 1910 daily record (41 degrees), and Lancaster was a crisp 38 degrees.

The odd chill seems fitting, after May turned out to be a month for all seasons.

On May 2, the mercury reached 79 degrees in Columbus. All seemed fine–until a strong cold front crossed the state the next day. On May 5, the high only reached 54 degrees, and morning readings dipped into the upper 30s early on May 6.

Even colder weather awaited, as another surge of Canadian chill on the edge of the polar vortex that normally hovers over northeastern Canada was unleashed, with a plunging jet steam reminiscent of a winter pattern.

The average temperature from May 4-13 was 13.3 degrees below normal in Columbus. Graupel (snow pellets) darted about northwest Columbus, and as far south as Hocking County (Rockridge) on May 11. The high of 45 degrees established a record low maximum for the date. Columbus reached a record low of 31 degrees on the morning of May 12, and a record-tying minimum of 34 on May 13, with widespread frost in low-lying areas again.

The middle of May brought a welcome warm-up briefly resembling normal spring. But then things turned historically soggy. Back-to-back daily-rainfall records of 2.33 inches on May 18 and 2.02 inches on May 19 caused flooding in northern portions of the Columbus area.

A total of 3.87 inches of rain at John Glenn Columbus International Airport in 24 hours on May 18-19 set a new May record, topping 2.72 inches on May 26-27, 1968. By the end of the week, the Columbus area received four to six inches of rain, with locally heavier totals. One gauge a little south of Circleville reported 6.5 inches.

A six-inch rainfall in 48 hours considered a 50-year event in central Ohio. The Olentangy River gauge at Worthington reached its highest level since Jan. 21, 1959. The river crested at 13.7 feet–the third highest level on record.

Roads turned into rivers at daybreak on May 19, and about 50 families were evacuated in Westerville. Flooding occurred downstream in Clintonville and Beechwold, and other parts of town reported high water. The floodgates and Greenlawn Ave. and Harmon Ave, (at Frank Ave.) were activated as water raced downstream. The Scioto River rose out of its banks in the natural floodplain from the Ohio State campus to COSI.

Bob Davis, a hydrologist who established an extensive rain gauge network in central Ohio in the 1990s, recalled the week-long rain and melting snow pattern in early January 2005, “when the U. S. Army Corps of Engineers set record pool levels at several of their flood control dams in the Scioto and Muskingum River basins. The rainfall (more than 8 inches in Columbus) that caused that flooding, however, was spread out over a number of days.”

The final week of May brought summer heat and July humidity, with seven straight days in the 80s: May 24-28 averaged 10.8 degrees above normal.

The unusual month of May ended with a fall-like pattern featuring fluffy clouds and a cool, dry northerly wind to complete the seasonal cycle. In the end, the average temperature in Columbus in May of 60 degrees was 2.3 degrees below normal, so to an extent the temperature extremes evened out.

The total of rainfall of 6.29 inches was more than 2.5 inches above normal, and raised the total precipitation for the year to a whopping 25.6 inches (15.57 inches above normal) in Columbus, the wettest start to any year in the city since 1890.

Copyright 2020 Nexstar Broadcasting, Inc. All rights reserved. This material may not be published, broadcast, rewritten, or redistributed.

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