Cold temps a new record for Sumter

7 nights below 20 opened year, but longest run below freezing was 22 days in 2000-01

BY BRUCE MILLS
bruce@theitem.com
Posted 1/11/18

The first week of January 2018 in Sumter won't just be remembered for New Year's Eve parties and college football bowl games.

According to the National Weather Service in Columbia, Sumter County set a new record last week with seven consecutive …

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Cold temps a new record for Sumter

7 nights below 20 opened year, but longest run below freezing was 22 days in 2000-01

Posted

The first week of January 2018 in Sumter won't just be remembered for New Year's Eve parties and college football bowl games.

According to the National Weather Service in Columbia, Sumter County set a new record last week with seven consecutive days with overnight lows under 20 degrees. The weather service's records date back to 1901.

Overnight low temperatures from Jan. 1-7 ranged from 11 to 19 degrees in the county, according to NWS Meteorologist Doug Anderson, as a very deep "long-wave trough pattern" of low atmospheric pressure over the East Coast brought cold air down from Canada.

"As that trough developed over the eastern U.S., it was deep enough and strong enough to provide us a sustained flow out of the Canadian arctic to bring that cold air down at all levels of the atmosphere," Anderson said. "It just didn't have anything to stop it."

The previous record for consecutive nights with lows less than 20 degrees in Sumter County was six, according to Anderson. That occurred twice: Jan. 3-8, 2010, and in December 1935.

Trough patterns are often associated with weather fronts and typically measured in weeks, Anderson said.

While Sumter experienced unusually low temperatures for the seven-day period, Anderson said the longest cold-weather front with temperatures below freezing (32 degrees) - likely the best measure of a cold-weather stretch - for the county is 22 days, and that occurred 17 years ago from Dec. 18, 2000, to Jan. 8, 2001.

Anderson also noted that last week's Winter Storm Grayson dumped 3 to 5 inches of snow in most of the county. Isolated places in the county recorded up to 7 inches of the white powder, he said.

Summerville, in Dorchester County, recorded the highest snowfall last week in the state with 7.3 inches, according to the National Weather Service. Sumter's 7-inch readings followed next for second highest in the Palmetto State. Other parts of Dorchester and Berkeley counties, outside of Charleston, recorded 6.8 inches of snow.

As far as the upcoming forecast, expect warm weather today followed by another cold snap this weekend, Anderson said. Today's high in Sumter should be in the mid- to upper 60s, and Friday's high should reach the low to mid-70s.

Isolated showers are likely later today and through Friday morning, he said. The heaviest rainfall should occur Friday afternoon, however. Anderson expects about a half inch of rain in total for Sumter.

Anderson said another cold front system is expected this weekend - though not as cold as last week. He said Saturday's high temperature is expected to be in the mid-50s in Sumter, while Sunday should only reach the mid-40s. Overnight lows should be between 30 and 32 degrees Saturday and 25 on Sunday night.

On Monday and Tuesday, high temperatures should reach the mid- to upper 40s, he said.

"Rest assured, we don't have a threat of snow though over the weekend with this new system," Anderson said.

Historically, for the month of January, high temperatures in Sumter County are normally in the mid-50s and lows are normally in the low to mid-30s, Anderson said.