A review of signifigant weather events in the LowCountry last year.
-Verizon Cell Tower in Estill, SC. Credit: NWS-
While 2020 was an unusually chaotic year, the weather across the LowCountry was chaotic in it's typical way. A mild start to the year robbed us of wintery weather for the second consecutive year, but severe weather in the spring made up for any quiet. Afterwards, a cool May was followed by a cool June, and an all around mild Summer. This Hurricane Season was the busiest on record, but we escaped most of the direct impacts. Finally, a rainy but tranquil Fall quickly flipped to Winter with severe weather on Christmas Eve and flurries the next day.
What happened to Winter?
The year started out warm (though not as warm as this year), with temperatues in the in the 60s and 70s. While portions of January did get chilly, a mild pattern led to the 12th warmest January in SC history, and an unsurprising lack of snow. Temperatures below freezing were also less common than normal. February was not any cooler, with temperatures continuing to be above average.
On the morning of April 13th, an extremely intense squall line traversed the region, dropping multiple tornadoes. The strongest tornado was a long-track, violent (EF4) that cut a path from Estill to Islandton. The supercell that produced this tornado remained embedded in the squall line and continued to drop tornadoes in Walterboro, Cottageville, Summerville, Moncks Corner, Bethera, and eventually Georgetown and Pawleys Island. An EF3 tornado tracked through Moncks Corner just as people were waking up on Monday morning. The squall line formed over the deep south and tracked well offshore into the Atlantic.
Cool Start to Summer
May and June were the first months to be cooler than average in 2020. A persistant Eastern trough allowed cool air from Canada to flow down into the area, bringing beatiful crisp days in a month usually marked by increasing heat and humidity. After a brief warm up in early June, a series of Upper Level Lows were "trapped" over the state. This allowed them to stall out and drop heavy rain. Alongside this heavy rain was dense overcast, and cool temperatures. In contrast to May/June 2019, this was a welcome treat.
The 2020 Atlantic Hurricane Season was incredibly busy, long lasting, and damaging. While the LowCountry was hit by Tropical Storm Bertha in May and brushed by Hurricane Isaias in August, there was very little impact from tropical cyclones. Bertha was in and out in a single morning, bringing only moderate rain to Berkeley and Charleston Counties, and Isaias only managed to kick up some sand and high winds along the coast.
A strong storm system and an attached cold front brought a surge in warm air and moisture to the area on Christmas Eve. An enahnced risk for tornadoes was in play as well, but fortunately there were only a few high wind gusts to wrap up the day. After the front cleared the area late that night, cold air quickly rushed in. A small blip of moisture happened to move over Walterboro, Cottageville, and North Charleston around 6AM Christmas morning. These snow flurries gave the airport an official trace of snow.