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It looks like the DMV could be hit with another round of winter weather this weekend.
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It’s important to note that the setup is completely different than the one that brought us snow last weekend in DC
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Fun fact: Tuesday morning has the potential to be DC’s coldest morning in 30 years.
WASHINGTON – The scraping of plows and shovels continues to echo across the area as the region digs out its heaviest snow of the year so far.
The final total of 6.9 inches of snow and sleet at Ronald Reagan Washington National Airport made it the fourth-highest snowfall for the city in a decade.
Baltimore (BWI Thurgood Marshall) had its heaviest snowfall since the January 2016 Blizzard, accumulating 11.3″ of snow. As cleanup continues, eyes are already turning to the weekend when another snow chance is on forecasters’ radar.
It’s a word that’s frankly been overused when discussing the cold air outbreaks of recent years: polar vortex.
In simple terms, this is a term used to describe an area of upper-level pressure in southern Canada that directs cold air into the United States. This time, however, I think the use of the term is justified because this low pressure wave has its origins in the polar region itself.
So cold is the air it’s directing into our region, where Tuesday morning has the potential to be DC’s coldest morning in 30 years, as long as the city drops to at least 4°F.
This is just one of the many incredible facts about how intense the cold will be here in Washington, DC. We’re forecasting lows in the single digits for each of the next five nights. We haven’t had so many consecutive nights of single-digit lows since 1899.
There’s also a chance we could go 7 and 10 days in a row where the temperature fails to break freezing here in DC, which would be our longest stretch since December 1989.
The point of all this is to say that while we’ve had a few cold winter spells in recent years, this one is abnormally strong for longevity and intensity. Additionally, any time you have an extended period of strengthening cold air – you need to be on the lookout for the potential for snow.
One thing I want to make clear is that this setup is completely different than the one that brought us snow last weekend in DC
While yes, there was a wave of low pressure that developed and brought snow to our region, the dynamics of that system was primarily driven by widespread overshoot.
A strong trough of low pressure in the west, leading to a widespread push of warm, moist air, forced up and over arctic air, which took root in the region last Saturday. That’s why the storm was so widespread, with winter storm warnings from New Mexico to Maine.
Instead, the setup for this weekend is much more “classic” in that the threat area would not be nearly as widespread as what happened last weekend, but the affected areas could be hit even harder.
This potential storm is driven by upper atmospheric energy crossing a strong ridge of high pressure over western Canada, sinking south across the Plains and Midwest. It meets up with southerly energy moving out of the Gulf later this week, and if timed correctly, the two strengthen to help fuel a powerful bomb cyclone pushing up the US East Coast.
A key term in which the words were, if timed correctly. To keep it simple, we technically have all the ingredients to form a nor’easter in the East this weekend. Strong blocking near the polar region and across Canada will keep cold air coming through the week, and a strong ridge of high pressure will push east across the western United States and into the Rockies.
This will keep the storm from moving into the interior of the United States, which reduces the threat of dealing with a mix or rain scenario like the one we had to deal with this past weekend. Instead, in such a setup, you run the risk of the ridge of high pressure to the west being too strong, and what that will essentially do is force the storm further east, where it either has less or no impact on the DC region.
The European model shown above shows this scenario from the most recent run…but the full reveal went back and forth between a near miss and a high impact snowstorm for the DC region.
So, in short, yes. There is a risk for more snow in the DC region and Northeast this weekend. The truth is that we are still in that forecast range where we have to watch the trends in the models to see if the storm might hug the coast or if it will be forced out (what we call suppression).
My general thoughts are that given the pattern, we should have a reasonable idea by Wednesday night or Thursday morning if we’re in for another wintry blitz or near miss. If it happens to hug the coast, there is the potential for even more significant snow than what we just went through this past weekend.
Stay tuned. We’ll have updates throughout the week.
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