DC winter weather: When could the next threat come?

WASHINGTON - Following what was our coldest stretch of weather since January of 2018, including our longest stretch of below freezing temperatures since December1989, temperatures to start off this week have finally managed to thaw some of the snowcrete that has gripped the D.C. region. 

The thermometer has broken the 40°F mark each of the last two afternoons...though that streak is likely at an end as colder air is set to return to the D.C. region tonight, ahead of even colder air this weekend. With this renewed cold, the threat of stronger refreezes is very likely. 

Overnight lows are expected to drop well into the teens heading into the weekend. Travelers, particularly during the morning hours, should watch for icy patches to develop anywhere melting has occurred, especially on lesser treated sidewalks and side streets.

Arctic attack:

The next shot at snow falling in the D.C. region comes along an arctic cold front that will pass the region by on Friday afternoon. 

The National Weather Service issued Winter Storm Watches for the mountain region west of town, warning up to half a foot of snow will be possible in the mountain highlands as the system passes through. 

Historically, the D.C. region tends to perform poorly with systems like this one when it comes to snowfall. It is the mountains themselves that cause this, as air is forced to rise to get over the mountains themselves. Think of them as a sort of atmospheric speed bump. 

A process known as downsloping occurs, where air is forced to sink and expand, which naturally dries out the air mass. So while the mountains will pick up the brunt of the snowfall, areas around D.C. will just get the leftovers. Scattered snow showers which may bring a coating to an inch of snowfall in some areas around our region.

Not everyone is expected to see these totals — they will be hit or miss and on the lighter side. No advisories were issued for the D.C. region, nor are any expected as snowfall is expected to be light and scattered, though since they could be present for the evening commute, drivers should exercise caution as even a coating can turn slick quickly. 

Saturday and Sunday will be drier, but breezy and very cold. With many not making it out of the 20s all weekend long.

The big melt:

The Polar Vortex — the term has been used a lot this winter already, and for good reason. It has been the cause of the severe arctic outbreak for much of the last two weeks and will again be responsible for this weekend’s coming cold burst. 

This weekend just my be its "last gasp" for a little while though, as the feature is expected to weaken and retreat northward towards the Polar region before settling over Siberia later next week. 

As it does so, milder temperatures are expected to fill in behind it. More widespread 40s are expected to return as early as Tuesday with middle-to-upper 40s to almost 50°F possible before the end of next week. 

While the massive piles of ice and snow that have popped up around the region will likely take weeks to melt away, the milder temperature regime should at least finally help cleanup efforts in our region with more substantial ground melting. Indeed the coldest stretch of winter just may be behind us, though that does not mean we are free from winter threats just yet.

Next threat window:

Contrary to popular belief, a prolonged, strong cold pattern does not necessarily mean a lot of snow. 

Cold air by its very nature is dry, hence why moisturizer and ChapStick is always flying off store shelves whenever temperatures stay subfreezing for so long. 

Storms themselves, to speak simply, are atmospheric chaos. They are the atmosphere reacting to changing weather patterns. So, forecasters are always on guard whenever a big pattern change is occurring, looking for the threat for a storm.

Weather models have been zeroing in on this next "window" for another storm, and they seem to be focused on the time between the day before Valentine’s Day and Presidents’ Day. Yes, despite the forecast warm up, temperatures are still cold enough, especially in the overnight and morning hours, that any storm that comes our way would be a potential winter threat.

Various weather models suggest that they’ll be strong wave of energy ejected out of the American southwest at the end of next week. Depending on where, and how it interacts with a dip in the jetstream around this time, it could develop into the next larger winter weather threat for someone in the eastern half of the country. 

While it is still far too early to pinpoint something like a storm track, forecaster are closely monitoring a feature known as the North Atlantic Oscillation, sometimes called the Greenland Block. When this feature is present, it forces storms to take a more southern track this time of year, and therefore makes the threat of winter weather more elevated. 

This feature will be present through next week, though will be weakening into Presidents’ Day Weekend. It is during this weakening that we should be on guard for a threat.

Are we talking snow, mix, rain...or a bit of all three? It is far too early to tell. It is at that time range of what I like to call the "early signals" phase. 

Models are hinting that a storm is going to form. What no weather model is going to nail at this range is the track of such a system. Is it a wave that passes south of D.C.? Is it our next winter storm? Or does it pass just northwest so we turn over to rain? 

While I cannot say which of these is most likely, I can say that’s a time period we should monitor.

I can also say with confidence that we will not repeat the Great Snowcrete Storm of 2026 from two weeks ago. The pattern around that time does not suggest that air mass in place will be nearly as cold as the one that impacted us ahead of, and particularly after, that storm system. It is a very different pattern, which means a very different potential storm system, whose potential impacts would be unlikely to last nearly as long.

We will keep you posted in the days ahead! Stay tuned to FOX Local...and stay warm!