Reviewing Last Week's Remarkable Cold Wave

Unusually cold air will prevail across most of the Eastern U.S. for yet another week, making some inroads into the central states. Snow and ice continue to plague parts of the South and Atlantic: significant sleet and freezing rain are possible today from northeast Texas into Mississippi. Another round of wintry precipitation is likely midweek across parts of the mid-South, with the focus beginning to shift westward in a long-awaited pattern change by next weekend.

Apart from these events--and the record snow burying most of New England--it’s the cold that’s made its mark on the eastern United States this winter. A growing number of locations are within reach of their coldest February on record, and the last several days have been one of the most intense periods of cold on record for so late in the winter season in the Ohio Valley, Michigan, and the Southeast. A preliminary total of 398 daily record lows were set and 60 tied on Friday, February 20, according to NOAA’s Daily Weather Records site. That’s one of the largest single-day swarms of record lows in recent memory. (January 6, 2014, saw a similar number in its final tally, but that was after data had been received by 4007 sites, about twice as many as in Friday's preliminary total.) Saturday racked up another 209 daily record lows broken and 23 tied.


Figure 1. Sunshine illuminates icicles in the winter-swathed landscape of Plainville, Massachusetts, on Friday, February 20. Image credit: wunderphotographer PvilleGuy.

Did we just witness the most intense U.S. cold wave so late in the winter? At some locations, that may be true, according to Weather Underground’s weather historian, Christopher C. Burt. He points out that if you examine the month of February as a whole, there are some strong challengers that occurred only a few days earlier in the month than the cold wave just experienced. “Concord, New Hampshire set its all-time record low of –37°F on Feb. 16, 1943, as did Portland, Maine with -39°F on the same date,” Burt said. Then there was February 1936, when all-time state record lows were set at Parshall, North Dakota (–60°F on the 15th) and McIntosh, South Dakota (–58° on the 17th). More recently, Alpena, Michigan set its all-time record of –37° on Feb. 17, 1979, as did Escanaba (–32°F), and Marquette (–34°F). The next day, Old Forge, New York, set the all-time state record with –52°F, and Syracuse set an all-time low with –26°F. Burt’s take on the “coldest so late” debate: no matter whether it's early or late in February, you're still in meteorological winter. “I really don’t think one should talk about record-breaking late season cold for any event that takes place in February. I would posit that not until March should such discussions become relevant.” Burt adds that a close look at region-wide anomalies, rather than individual stations, is the way to find the rightful place for last week’s event next to other frigid February periods.

One challenge with assessing local records is that many of the nation’s oldest reporting stations have moved one or more times in their history. NOAA has made an effort to “thread” these datasets into continuous long-term records, but not all databases are complete and some aspects of station history can be difficult to unearth. Last Friday, we reported that Flint, MI, had tied its all-time record on Friday of -25°F, originally recorded on Jan. 18, 1976. Weather records expert Maximiliano Herrera wrote me to note that the records at the Flint airport go back to 1948, not 1921 as is commonly stated. Measurements were taken at a different location 7 miles from town from 1921 to 1948, and it turns out that Flint dipped to –28°F on Feb. 14, 1916, at another, still-earlier reporting site. Also, Jamestown, NY, tied rather than broke its all-time high, since the town reached –31°F on Jan. 5, 1904. More details pertaining to these and other records can be found at Herrera's comment (#1041) on Friday's blog post. Herrera maintains a comprehensive list of extreme temperature records for every nation in the world on his website.

Visit this week’s Portlight Strategies workshop via livestream
Portlight Strategies, Inc. and the Hampton Roads Regional Catastrophic Planning Team will present the Getting It Right Workshop this Tuesday and Wednesday, Feb. 22 - 23. The workshop will provide tools to facilitate full integration and inclusion in all aspects of emergency preparedness and response. Speakers include representatives from FEMA, the American Red Cross, and disability stakeholder organizations. The proceedings will be livestreamed starting at 9:00 AM EST on Tuesday. Founded and staffed by members of the Weather Underground community, Portlight Strategies is a 501(c)(3) organization that facilitates a variety of projects involving people with disabilities, including post-disaster relief work. Portlight's longest-running disaster recovery effort unfolded over 18 months following the devastation of Superstorm Sandy in the shore communities of New Jersey and parts of New York City.


Figure 2. The iconic Flatirons of Boulder, Colorado, on Monday morning, February 23. Although much of the western U.S. is dealing with drought, Boulder is having a record-snowy February, with 38.4" recorded through Monday morning at the local COOP observing station on the NIST/NOAA campus. Boulder snow records go back to 1899, with reliable COOP station data beginning in 1990. Image credit: Joshua Wurman, Center for Severe Weather Research.