A January To Remember

While we had some wet weather in December of 2021, the September-December 2021 time frame  was very quiet weather wise  around here. We didn't have many storm systems, and certainly had few impactful ones. While 2021 went out like a lamb, 2022 came in like a lion.

In the days preceding this event, models were consistently showing a shot of rainfall along a cold front passing through the region. It looked like the bulk of the lift, though, was going to pass to our north. It seemed like a pretty typical winter event. But then, in the last 24 hours or so before the event, model guidance began to show a more impactful scenario unfolding. The models trended towards a more intense shortwave trough closing off over the TN River Valley, and forcing a rapidly strengthening surface low over our forecast area.

This quick of a forecast change isn't too common, as usually by the 24-36 hour timeframe model guidance has a good handle on the situation. But because the models indicated a more potent shortwave trough, heavy rainfall, severe weather, and strong, non-thunderstorm winds all became possibilities. By Sunday, the SPC had us outlined in a Slight Risk for Severe Thunderstorms, and WPC indicated an increasing threat for some flash flooding.

The models ended up depicting the scenario correctly, with a strong surface low and cold front pushing into the region early on January 3rd. Because this was deepening so rapidly, we had very intense non-convective winds. This occurs because air must rush from areas of high pressure to fill the void of air in the low pressure, thus creating strong winds.

As the low approached, we thankfully did not get enough instability across the area to see severe weather along the cold front. However, widespread heavy rainfall preceded the low. This certainly set the stage for significant issues with the winds. As the cold front passed, strong winds developed across the entire Midlands and CSRA, with gusts between 45 mph and 60 mph common. With wet soil, there was plenty of tree damage, and lots of power outages across the state.

This kind of event is rare around here, especially outside of tropical events. You don't typically get intense, non-convective wind events outside of rapidly intensifying low pressure systems, and this fit that bill. It just doesn't happen around here very often.

Satellite imagery captured this event well, showing a classic rapidly intensifying mid-latitude cyclone. Additionally, it picked up on an area of enhanced descent in the atmosphere that passed through the region between 330a and 530a, collocated with the most intense wind gust reports. This feature, plus the passage of the cold front, helped to mix down even stronger winds just off the surface and result in widespread damaging winds.

All in all, this was one of the more impactful weather events that we had across the region since the April 13, 2020 tornado outbreak. Upwards of 400,000 people were without power by the morning of January 3 between Georgia, North Carolina, and South Carolina.

A couple weeks passed between events, and as we headed into the second full week of January, models began to hone in on a winter storm. For context, we hadn't seen a widespread winter storm across even half of our area since 2014, and models/ensembles were indicating that this would turn into one. And ultimately, an ice storm with 0.20"-0.50" of ice across a large chunk of our area was impactful.

The setup for this event was pretty classic in terms of getting an ice storm, especially along and north of I-20. A strong Canadian high pressure pushed into the Mid-Atlantic and Northeastern US by Saturday night. Upstream, a strong shortwave trough was digging into the ArkLaTex region, and overspreading strong lift across the southeast. Meanwhile, mid-level convergence led to sinking air across the Mid-Atlantic and was helping to force high pressure into the Carolinas. This produced a cold-air damming (CAD) event across the Carolinas, which is a classic freezing rain set up for the Columbia forecast area.

As precipitation blossomed across the southeast, our surface temperatures were slowly falling across the region. The strong high pressure was pushing that cool and dry air into the region. As rain then moved into the region, it fell into this dry air and cooled the surface even more. By 7a Sunday, thanks in large part to evaporative cooling, the freezing line had made it to the I-20 corridor. Along and north of there, widespread moderate to heavy freezing rain and sleet was noted and accumulated quickly.

Freezing rain is so dangerous because it is basically just freezing water on any surface below freezing at the surface. This leads to a layer of ice encasing everything. Once this accumulates to >0.25", trees and power lines really struggle with the weight on them. This is the basic process of freezing rain:

I should note: freezing rain wasn't the precipitation type for the entire event everywhere. It started as rain in the central Midlands, and sleet in the northern Midlands. However, everyone north of I-20 saw at least some period of freezing rain, with several places seeing significant amounts accumulating.

Confidence in ensemble & deterministic guidance and consistency had grown to the point where the office was able to begin messaging the possibility of a winter storm as early as January 11th. The signal was strong in the models, and the consistency was there from an early time that is unusual for any kind of weather event, let alone a winter weather event.

In the following days, model guidance continued to hone in on an impactful Ice Storm occurring. This was expected to primarily impact those along and north of the I-20 Corridor. Confidence grew to the point where a Winter Storm Watch was issued in the 2.5-3 Day range, helping us focus messaging to our local and state partners. This was a well forecast event, owing in large part to pattern recognition (seeing the CAD event set up) and consistent model guidance. The NWS products issued are below.

Freezing rain reports flooded into the office on Sunday, and the ice accumulated quickly. When all was said and done, a widespread area of >0.25" of ice had fallen across the northern Midlands. This led to plenty of power outages by Sunday afternoon, with over 100,000 without power in SC at the peak, and over 200,000 without power across the southeast.

Given that it had been nearly 8 years since our last widespread & significant winter weather, why not make it two winter storms within one week in 2022? Who would have thought! As the Ice Storm was winding down, our attention turned to model ensemble guidance that was depicting another impactful winter storm only 5 days after the ice storm! By Wednesday, confidence was high enough to issue a Winter Storm Watch for many of the areas that had already seen ice.

However, unlike the ice storm, model performance was....sub par on this one. This led to significant uncertainty in the immediate lead up to the event itself. By Thursday afternoon, some models kept us completely dry, while others had widespread sleet/snow. This uncertainty allowed for an upgrade from a Watch to a Winter Weather Advisory. There was far too much unknown on January 20 to upgrade to a Winter Storm Warning just yet.

However, as we got into overnight on the 20th and early on the 21st, model guidance started to shift again, this time in the direction of snowfall across much of the Midlands. Take a look at how much the Hi-Res Ensemble Forecast (HREF) model shifted within 5 runs.

Hi-res guidance backed up some of the skeptical larger scale models, at least initially. However, as you can see in the above images, the model quickly trended towards the Midland's largest snow in about 8 years, depicting 1-3" falling across the central and northeastern Midlands. This led our staff to quickly coordinate and issue a Winter Storm Warning that included the Columbia Metro area.

This ended up working out and actually resulted in a record snow for the day at Columbia Metropolitan Airport! 2.0" fell, breaking the old record of 0.1" in 1983. To the northeast of Columbia, upwards of nearly 4" fell in parts of Chesterfield County.

The snowstorm came at a perfect time, with all of the snow falling after rush hour, remaining overnight, and largely melting (at least in the Columbia and Lexington areas) by noon on Jan 22. It did result in a very pretty snow, though.

This one was a quick hitter, but was still fairly impactful in some areas. Models were not super impressed with the event leading up to it, basically showing a fast moving system that laid maybe a dusting up to 1" of snow. And generally that is what happened.

The setup for this was actually pretty interesting, with a strong upper level low passing directly over the region. This helped to force some showers, and as temperatures cooled through the night, snow showers developed. This was fairly well forecast event, with a Winter Weather Advisory being issued by the office a day ahead of time, and the snowfall forecast working out well.

Much like our snow event the weekend before, this snow melted quickly and didn't really lead to any issues across the region. Even still, it is rare to get one snow event around here - let alone two within a 7 day timespan!

This event really put us over the top in terms of an active winter. Not only did we have one winter storm, we had three in three weeks. This is very uncommon around here, and is one of the most active winter weather periods we have had in the last 10-15 years.

In the month of January, Columbia issued 8 total winter weather products between Winter Weather Advisories, Winter Storm Watch/Warning, and Ice Storm Warnings. For this same timeframe, it was 2.0 standard deviations above normal! Note in the second image on the left that much of the eastern US was 1.5-2.0 standard deviations above normal on winter weather products during the month of January, indicating a cold and wintry period.

And it was quite cold in the eastern US during the month of January, with many areas below normal for the month of January. This led to an active winter weather month, as seen in the data above.

Truly, between the wind event and the major winter storms, this was a January to remember. It'll go down as one of the more active winter weather months we've seen, and surely be memorable to the residents of central SC and the CSRA of Georgia. We'd like to take a minute to thank all of our COOP observers and all who tweeted in or sent in reports! Your measurements are very valuable during and after the event. We'd also like to thank our state partners and neighboring NWS offices for smooth collaboration and work!