WASHINGTON - Believe it or not, winter hasn't even started yet and we are already talking about a second cold air outbreak across the United States. The first strong cold air outbreak is poised to hit the region this weekend, with many staying in the 30s throughout the daylight hours of Friday and Saturday. Evening lows fall may into the 20s and even teens for a few locations.
But consider yourself warned: those temperatures may feel mild compared to what is coming our way next week-- which looks to rival even strong mid-winter cold air outbreaks.
Here are five things you need to know about next week’s cold air outbreak…
#1: The Trans-Siberian Orchestra
Well, it is the holidays after all-- so I had to get at least one holiday reference in! There is, however, more to this reference than just an awesome guitar heavy version of the Carol of the Bells, as the cold air we will soon experience has a strong Siberian connection.
We mentioned in our winter outlook that we released back in late October that one of the reasons we were favoring stronger cold this winter was because of the extreme amount of snowfall seen in Siberia during the fall months. There has been a record-breaking expanse of snowfall across portions of Asia, and cold air has been building over the snowpack for the better part of the last two months.
This weekend, a strong area of upper level high pressure building over the Chukchi Sea (north of Alaska) will provide the needed connection for some frigid air to cross the Polar region and spill into the United States, beginning in Northwest Canada this weekend and progressing eastward into our neck of the woods sometime on Wednesday of next week.
#2: The return of the Polar Vortex
Sounds like the title to a winter horror movie, doesn’t it? To avoid upsetting the meteorological community, it is not actually THE polar vortex, but a “piece” of the polar vortex that will be traversing Canada next week. It will not make it this far south, and no, you will not be able to look up in the sky and see it, regardless of what the internet tells you.
The polar vortex will be on its closest approach next Thursday as it rotates through the Hudson Bay in Canada. While it might sound ominous, polar vortexes are merely an atmospheric mechanism for transporting cold air southward. And it will do just that: grab brutally-cold air from northern Canada and push it into our region for the latter half of next week.
This will not be an extended visit however. By next Friday afternoon, the polar vortex is losing strength as it starts its journey back to the Pole, and by the weekend it is out of our hair… although the cold air it supplies will linger for a few days.
#3: Just how cold are we talking here?
For the Washington, D.C. region, we are talking about temperatures 10-15° below normal next Thursday and Friday. Before you say. “Hey, that doesn't sound too bad!” keep in mind that during this time of year, average high temperatures are only in the middle 40s in downtown D.C., so we are talking about spending the majority of the day below freezing.
Suburbs will of course see the worst of it without the warming effects of the concrete and asphalt of the city (the “Urban Heat Island Effect”), and many of our northern and western suburbs are expected to stay in the 20s during the afternoon before falling into the teens with perhaps an isolated single digit reading or two during the overnight hours. The risks with the event lean colder as well, with the most extreme models calling for lows in downtown Washington to fall into the mid-teens and afternoon temperatures to stay in the 20s all day long.
That's strong cold, yes, but not record-setting by any means. Record low maximums in Washington, D.C. are in the lows 20s next Friday and Saturday, with record lows in the low teens and single digits. While this will be the coldest December air the region has seen in at least three years, it is not expected to reach those extremes.
#4: Winter’s fury unleased nationally
Despite the cold, the D.C. region will get off with a slap on the wrist compared to other parts of the county. Temperatures in Calgary in Alberta, Canada are already subzero as you are reading this, and they are not expected to rise above 0° at any point over the next five days. In Minneapolis, forecasters are calling for subzero low temperatures with highs only in the single digits between Tuesday and Thursday of the upcoming week.
The same fate may await Chicago on Wednesday, where the local National Weather Service office is calling ominously for a low of 0° Wednesday morning. Major cities as close as Pittsburgh, PA may be looking at single digit low temperatures. This early in the winter season that Great Lakes remain unfrozen and, as Arctic air invades the region, the lake effect snow machine will be cranking with authority. Parts of upstate New York and Pennsylvania will be digging out of feet of snow by the time next weekend arrives.
#5: Any snow risks for Washington?
Are there risks? Absolutely. To what degree? Well, we're not too sure yet. (Insert classic joke about weather people not knowing anything here).
The way things look right now, the D.C. region will have three chances for impactful winter weather over the next two weeks. The first is Monday morning, with a storm system sliding through the Midwest and into our region. The storm center looks to pass well west of the region, which is a track that brings warmer air up from the south as the precipitation moves in. However, with cold air in the region this weekend, there could still be come left over cold air stuck near the surface as warm air spills in overhead. This could lead to some issues with freezing rain or sleet (especially area north and west of town) before everyone switches to all rain by the end of the morning. Details on timing and just how much precipitation will be in the region during the morning hours are still being assessed, and we’ll continue to update you through the weekend on this potential.
The next chances have to do with next week’s cold air outbreak. Our region always sees its best chance for impactful snows either as cold air is pushing into the region, or exiting the region. Several models are hinting at these possibilities next Wednesday evening/Thursday morning as an area of low pressure rides the Arctic cold front. This would lead to the potential for a rain-to-snow event as cold air overtakes the region. From experience however, these types of system tend to look impressive in weather models when they are a week away, but tend to lose their vigor as models get closer and closer to the day of that event. It is a timeframe we are watching, however.
The third chance would come as the cold air starts to exit next weekend. Warm air from the south will want to take its place, and with it may come some southern moisture. The blizzard of January 2016 was a storm that came as cold air was lifting away. Recall temperatures in D.C. hit the low 50s just a few days after the snow stopped falling. Weather computer models are showing hints of some unsettledness around this time frame next weekend, but it is still far too early in this case to determine whether or not we are talking rain, snow, or nothing at all.
So yes, snow chances exist. However, the very nature of winter storm forecast is difficult. Remember, you have to have a number of atmospheric ingredients come together in the right time and place for a good snow event in our region. The cold air is a big one, and we will have plenty of that these next two weeks, but we do not know whether or not the other ingredients will present themselves at the right time just yet.
Know we will do our very best to give you as much warning as possible if a winter storm is brewing. As I sit here on this Thursday afternoon, know that we do not see anything major right now. Every day brings updated weather models and forecasts however, and the forecast will certainly change. So be sure to stick with us and check back frequently for the latest information.
The FOX 5 weather team is here to keep you one step ahead of winter weather all season long!
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