A Christmas Chill Decked December’s Halls

December’s temperatures had been marked by a giant cooldown simply in time for Christmas. Rain all through the month lifted the Mountains out of drought. And a brand new software function helps us put the previous month in perspective.

Temperatures Tumble for the Holidays

After a heat begin to December, our temperatures got here crashing down throughout a Christmastime chilly air outbreak, which skewed the month-to-month common temperature barely under regular. The Nationwide Facilities for Environmental Data (NCEI) notes a preliminary statewide common temperature of 41.6°F, or our 61st-coolest December out of the previous 128 years.

The primary week of the month noticed our excessive temperatures climb almost 10 levels above regular, with mid-60s throughout the japanese Piedmont and a balmy 80-degree day in Wilmington on December 7 below the affect of offshore excessive strain.

A sequence of frontal passages throughout the center of the month helped mood our temperatures to near-normal ranges and introduced clouds and rain throughout the western two-thirds of the state.

However essentially the most drastic temperature change got here on December 23 as frigid air related to an Arctic excessive strain system spilled southward and infiltrated many of the continental United States.

On the next morning, clear skies, calm winds, and the chilly air mass in place helped temperatures drop to ranges not seen in a number of years. Mount Mitchell recorded a low temperature that morning of -21°F, which was tied for the Seventh-coldest studying within the 90-year historical past of climate observations on the state’s highest peak.

Elsewhere within the Mountains, our ECONet station on Wine Spring Mountain in Macon County bottomed out at -15°F, which was the coldest day there since observations started in 2002. At websites together with Asheville (0°F), Boone (-8°F), and Flat Springs (-11°F), it was the coldest morning since an Arctic air mass arrived in early January 2014.

Most Piedmont websites dropped into the one digits on the morning of December 24, which is a uncommon occasion notably with out having any snow on the bottom. Greensboro recorded a low of 5°F, Charlotte hit 9°F, and Raleigh reached 10°F and its coldest morning since one other 10-degree studying following the January 2018 snowstorm.

Throughout the Coastal Plain, temperatures had been usually within the teenagers, together with 13°F in Rocky Mount, 15°F in Greenville, and 19°F in Manteo. In these areas, it was a chill paying homage to December 1989, albeit with out the blizzard that accompanied that 12 months’s Christmas cooldown.

Temperatures solely rebounded barely on Christmas Day, with excessive temperatures within the 10s and 20s within the Mountains, within the 30s throughout the Piedmont, and barely reaching the low 40s down east.

For locations equivalent to Brevard (a December 25 excessive of twenty-two°F), Mount Ethereal (28°F), and Morganton (30°F), it was the coldest Christmas afternoon since 1983. It was additionally a giant distinction from the T-shirt climate final Christmas, when highs hit the 70s throughout the state.

That form of heat did reappear earlier than the tip of 2022, although. The return of excessive strain ushered in above-normal temperatures lower than per week after the deep freeze. Components of japanese North Carolina reached the low 70s on December 30 and 31 to finish the 12 months on a excessive observe – or at the very least on a excessive temperature.

Mountains Out of Drought, Then Snowy for Some

December continued our fall sample of moist climate within the west whereas japanese North Carolina remained dry. NCEI stories a preliminary statewide common precipitation of 3.10 inches and our 51st-driest December relationship again to 1895.

Within the Mountains, the place pockets of Average (D1) and Extreme Drought (D2) had been in place initially of the month, the primary few weeks of December noticed a number of heavy rain occasions that erased any drought or dryness in that a part of the state.

Murphy picked up 2.24 inches on December 6 alone and completed the month with 6.23 inches, or its 14th-wettest December since 1967. That rain helped enhance streamflow ranges, which had declined throughout most of September and October however rebounded starting with Hurricane Nicole in mid-November.

One other rain occasion on December 14-15 introduced a widespread inch or extra throughout the Mountains and Piedmont, together with 2.20 inches at our ECONet station in Oxford. That web site had 4.52 inches for the complete month, which was its Seventh-wettest December previously 23 years.

For japanese North Carolina, the wettest and most impactful precipitation occasion got here on December 22 as a low strain system developed simply offshore.

That rain got here as a welcome aid for coastal areas that began the month with a string of dry days. From December 1 to 14, Wilmington acquired solely 0.08 inches of rain. They picked up 1.45 inches on December 22, though it nonetheless completed as tied for the Thirty seventh-driest December on file there and Average Drought stays in place throughout a lot of the Coastal Plain.

When the Arctic entrance got here via the following day, it whipped up gusty winds statewide. Our Mount Mitchell ECONet station measured a hurricane-force gust of 76.5 mph at 11:32 am, and ten consecutive hours with wind chills lower than -50°F, together with a minimal worth of -58.8°F simply after midnight on December 24. That’s the coldest wind chill on file for our Mount Mitchell station relationship again to 2008.

Grandfather Mountain had a peak wind chill of -55.6°F and Mount Jefferson had a wind chill of -45.6°F after the entrance roared via. Our coastal websites in Clinton, Goldsboro, Kinston, and Plymouth all recorded wind gusts in extra of fifty mph.

These robust westerly winds additionally produced a soundside overwash alongside the Outer Banks that closed components of Freeway 12. And when the chilly air moved in behind the entrance, standing water on the street froze into black ice and other slushy, slick spots in a single day.

That wasn’t the one space with one thing frozen on the bottom over the vacations. Temperatures had been chilly sufficient for precipitation to fall as snow at some high-elevation mountain websites, which gave a White Christmas for a fortunate few.

Mount Mitchell had 4 inches of snow accumulation on December 23, whereas Beech Mountain had 3 inches and CoCoRaHS observers close to Boone measured as much as an inch on the bottom.

For the remainder of us, we’ll must see if January – climatologically our snowiest month, and when almost all of our snow fell final 12 months – brings comparable wintry scenes as we start 2023.

December, as Advised by Thresholds

We just lately rolled out a brand new function in Station Scout, our software for viewing climate stations throughout the state. On the Thresholds panel, you possibly can view the historic prevalence of particular climate situations, equivalent to temperatures above or under a particular threshold worth, and abstract statistics together with the common first and final day per 12 months assembly that threshold.

This panel replaces our Local weather Thresholds software whereas preserving its visualizations and performance, and increasing these to cowl extra station networks.

Utilizing the Thresholds panel, we will put a few of our December climate right into a climatological context. For example, let’s first have a look at the prevalence of every day minimal temperatures lower than 10°F in Charlotte:

Because the annual prevalence chart exhibits, single-digit lows had been as soon as a reasonably frequent occasion, taking place as many as 4 occasions per 12 months within the Sixties. Nevertheless, these chilly mornings have turn into a lot rarer just lately, with simply 8 whole occurrences previously 20 years, together with on December 24, 2022.

On the opposite finish of the temperature spectrum, we will see how frequent it’s to have most temperatures attain at the very least 70°F in Wilmington presently of 12 months:

The Port Metropolis has averaged 6 December days that heat traditionally, however every of the previous 4 years has exceeded that common, as seen on each the Annual Chart and the Annual Desk (proven above) visualizations. WIlmington had 7 December days within the 70s or hotter in 2022, 18 such days in 2021, and a file 21 days that heat in December 2015.

Lastly, for these high-elevation areas that picked up snow final month, we will see how the timing of this season’s first snowfall compares to the historic common.

On Mount Mitchell, the common first day with measurable snow since 1980 is November 11. That made this 12 months’s first snow on December 23 greater than a month later than regular. Our state’s highest level can even anticipate to see snow as late as mid-April, with a median final snowfall date of April 17.

To view comparable statistics for climate stations close to you, go to our Station Scout software, choose a station utilizing the map and search choices, and click on on the Thresholds tab to start exploring.

And for extra views in regards to the previous 12 months, be part of us just about for our 2022 Climate 12 months-in-Overview webinar on Tuesday, January 17 at 11 am. Registration is required utilizing this kind, and also you’ll obtain a reminder and a hyperlink to hitch the webinar through Zoom.