While it couldn’t make an appearance during winter, it’s taken till nearly mid May for the tropospheric polar vortex to come crashing south.

A final stratospheric warming event combined with stratosphere to troposphere coupling and significant height rises into Alaska led to one of the strongest May Arctic Outbreak’s on record.

One of 2 pieces of the tropospheric polar vortex dropped south over central and eastern North America. Incredibly, -40C/F was measured at 500mb above Albany, NY. Well beyond anything measured in May before.

Was just tying a ribbon on the Northeast cold snap. The -40.1°C 500 mb temp in Albany last night just visually is an incredible historical outlier for data we have back to 1948 or so. The red X represents basically last night’s 00z sounding. Blue line is records. pic.twitter.com/V2RewdsTLm

— Matt Lanza (@mattlanza) May 10, 2020

So, each NWS office has records from ballon launches of temperatures at various levels of the atmosphere. In May the record for the NWS on Long Island at 500mb (18K ft up) was -34C, now it’s -38C. Astonishing. Many sites in the NE are shattering records during this cold pool. https://t.co/29ccsfUIdh

— Jeff Berardelli (@WeatherProf) May 10, 2020

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Record Cold Extreme at 850mb(5000') in the books over NYC/Long Island. Actual OBS from Balloon shows the temp was -10.3°C (13.4°F!). Beating -8.3C record for month of May. Even -10C over Philly. At 500mb it was -28.7°C (-19.6F). Wow! Impressive Airmass for May pic.twitter.com/PL9y1WGzqO

— Ralphs Weather OBS (@WeatherNut27) May 9, 2020

A number of May 9th low temperature records were broken or tied this morning. Binghamton NY broke their record for the coldest temperature in all of May. State College PA tied their May low temperature record. pic.twitter.com/QHorBbvphV

— NWS Eastern Region (@NWSEastern) May 9, 2020

From weather.com

Cold Notables

New daily record lows for May 10 were set Sunday morning in Trenton, New Jersey (31 degrees); Richmond, Virginia (32 degrees); Shreveport, Louisiana (47 degrees); and Wilmington, North Carolina (41 degrees). Boston and Providence, Rhode Island, both tied their daily record lows of 34 degrees Sunday morning.

All-time May record lows were set Saturday morning in Binghamton, New York (24 degrees); Fort Wayne, Indiana (23 degrees); Indianapolis (27 degrees); New York’s LaGuardia Airport (36 degrees) and Jackson, Kentucky (30 degrees). State College, Pennsylvania (27 degrees), New York’s JFK Airport (34 degrees) and London, Kentucky (28 degrees), tied their all-time May records Saturday morning.

According to the National Weather Service, prior to Saturday, the latest spring date Fort Wayne, Indiana, plunged to 23 degrees was April 20, 1897, and 1904, almost three weeks earlier in the spring.

Nashville, Tennessee, also plunged to its coldest low so late in spring Saturday morning, beating its previous record-latest 35-degree low by three days.

Washington’s Reagan National Airport (37 degrees) dipped to its coldest May low since 1966. Peoria, Illinois, had its latest spring freeze since 1971.

Van Wert, Ohio, plunged to 18 degrees Saturday morning, the first time it had dropped into the teens in May in 127 years of records.

Wind chills were as cold as the teens, even upper single digits, in parts of the East Saturday morning.

Boston’s temperature only rose to 44 degrees Saturday afternoon, setting a new record-cold high temperature for May 9.

New daily record lows for May 11 were set Monday morning in Bismarck, North Dakota (24 degrees – tie), International Falls, Minnesota (21 degrees), and Columbia, Missouri (36 degrees).

Snow Notables

Pittsburgh reported a trace of snow both Friday and Saturday, the first consecutive May days of snow there in 97 years.

And, as noted by National Weather Service-Charleston, West Virginia, meteorologist Nick Webb, Snowshoe, West Virginia, set its record 24-hour May snowfall in 45 years of records. Elkins, West Virginia, also set a new 24-hour May snow record, picking up 1.5 inches of snow Friday.

This forecast prompted the National Weather Service office in Caribou, Maine, to issue its first May winter storm warning in at least 15 years.

Rare May lake-effect snowbands and snow squalls spread across the Great Lakes and interior Northeast on Saturday. Overpasses were snow-covered in parts of western Pennsylvania, according to live cams.

Graupel mixed in across parts of the Interstate 95 corridor.

May 1-12th temperature anomaly. This is one of the coldest ever first 2 weeks of May for North America!

Tags: may arctic outbreak, record May cold