Sumter sees 3rd-coldest January lows

Records go back to 1930; January cold temps push daily averages to 6th coldest

BY BRUCE MILLS
bruce@theitem.com
Posted 2/13/18

We all know January was cold in Sumter. Just how cold was it?

To find out, The Sumter Item called the National Weather Service in Columbia to get the official numbers and look into the record books.

According to NWS Meteorologists Doug …

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Sumter sees 3rd-coldest January lows

Records go back to 1930; January cold temps push daily averages to 6th coldest

Posted

We all know January was cold in Sumter. Just how cold was it?

To find out, The Sumter Item called the National Weather Service in Columbia to get the official numbers and look into the record books.

According to NWS Meteorologists Doug Anderson and Chris Rohrbach - and their official databases - Sumter County's average overnight low temperature for the entire month of January was 25.4 degrees. That's the third-coldest average overnight low for Sumter in January dating back to 1930, according to NWS files. January 1940 was the coldest, with an average nightly low of 24.8 degrees, Anderson said.

The average overall daily temperature - between the lows and highs - for the 31 days of January in Sumter County was 38.6 degrees, ranking as the sixth-coldest January by that particular indicator for the county.

It was all driven by two stable, long-wave trough patterns over the East Coast that brought cold air down from Arctic Canada, Anderson said.

The first cold snap occurred at the very beginning of the month, Jan. 1-7, where for seven consecutive nights the overnight low was less than 20 degrees in Sumter. That was a new record for consecutive nights in the teens or below for Sumter, according to Anderson. Another cold snap occurred in the middle of the month.

"Sumter had two unusually cold snaps, and in both cases, stable, long-wave trough patterns set in and lasted a week or more," Anderson said.

Anderson explained with a typical three- to five-day trough pattern, cold air doesn't generally move below the Appalachian Mountains and into South Carolina.

"That long period," he said, "helped that cold air filter up and over the mountains to reach us."