Dangerous Cold Envelops Washington, D.C.

Glen Echo, MD   February 2015

Tonight and tomorrow are setting up to feature the coldest weather in more than two decades across the Mid-Atlantic Region.

More specifically, on January 19, 1994, the temperature fell to a bone chilling -4 degrees with a high of only 8 degrees in Washington, D.C.  Suburbs were even colder such as at Dulles Airport in nearby Virginia that saw a record low of -6 degrees.  Washington, D.C. hasn’t been below 0 since then and that was also the last time there was a high temperature in the single digits.  The Nation’s Capital hasn’t seen a temperature below 5 degrees since it was 3 degrees on January 21, 1994.

Tonight’s temperatures are expected to fall to the single digits downtown while many areas in the suburbs will likely fall below 0 as the coldest blast of arctic air of the winter reaches the DC Metro Region.  This extreme cold has been caused by a pronounced dip in the northern branch of the jet stream (a river of air in the upper atmosphere that steers weather in our part of the world) that’s ushered in an arctic area of high pressure.

As cold as this week has been (with a number of record lows already set in Baltimore and at Dulles Airport) Washington, D.C., hasn’t set any records yet but that’s likely to change.  Here are the local records that are in jeopardy tomorrow (February 20).  Once we know which of these records have been tied or broken, I will write a follow up column.

National Airport (Washington, D.C.’s official weather observing site):

Record Low: 8 (1896)
Record Low High Temperature: 18 (1896)


Baltimore, MD (measured at BWI Airport):

Record Low:  4 (1979)
Record Low High Temperature: 18 (1896)


Dulles Airport (in nearby Sterling, VA):

Record Low: -2 (1979)
Record Low High Temperature:  26 (1972)

Extreme Cold in the Nation’s Capital

President's Day Snow 2015, Bethesda, MD

The last week has already featured two different snow events in the Mid-Atlantic Region, combined with some of the coldest weather in recent memory.  Although last month wasn’t as cold as January 2014 in the DC-Baltimore corridor, this week has already seen record cold with more expected the next few days.

A big difference between last winter and this winter is while last February featured more snow than this month has, February 2015 has featured more extreme cold.  There were no observed single digit temperatures at any of the DC Metro Region’s three major airports last February, while there have already been several such days so far this month.

As of this morning, Dulles Airport has observed four days with single digit temperatures this month – including two record lows.  Meanwhile, BWI Airport has also seen two days with record low temperatures in the single digits so far this month.  However, National Airport hasn’t been quite as frigid without any single digit temperatures since January 2014.  That can at least partially be attributed to its close proximity to downtown Washington, D.C. which is often a little warmer than more suburban areas (such as Dulles and BWI Airports). 

As if this weather hasn’t been bone chilling enough, a powerful cold front will usher in an even stronger blast of arctic air this evening.  This cold front will be similar to the front that came through the Mid-Atlantic Region this past Saturday.  Of course we all remember last Saturday’s brief burst of snow that came with really gusty winds.  The difference between that front and this evening’s front is timing.  There was no rushour on Saturday, but today’s evening commute could be adversely affected by reduced visibility with some brief snow showers.  Once the cold front passes, dangerously cold air will re-envelop the DC Metro Region.

We are talking about even colder temperatures than earlier in the week as highs tomorrow and Friday are poised to remain at or below 20 degrees – even downtown.  More significantly, overnight low temperatures downtown will fall to the middle single digits tomorrow night, while many suburban areas may fall below 0!

It’s exceptionally rare for temperatures to be in the single digits in this part of the country and rarer still to be discussing temperatures around 0.  According to National Weather Service records, National Airport hasn’t been below 0 in more than 20 years since January 1994.  Baltimore hasn’t been below 0 since February 1996.  Although, Dulles Airport fell below 0 twice last winter, it’s quite rare there too.  While much of the Eastern United States has experienced record cold and snow this week, the Western United States has experienced the opposite.  Above average warmth continues for much of the West and Southwestern United States.  

For the latest updates on this evening’s cold front and the expected record cold the next few days, you can rely on your favorite meteorologists including my colleagues on the WUSA9 weather team. 

President's Day Snow

President's Day Snow 2003   Source: NWS

This part of the country has had a number of significant winter storms in mid-February.  In fact, some of the largest snowstorms on record in this part of the country have occurred right around President’s Day.  As I wrote about in a recent column, appreciable snowfall in the Nation’s Capital requires the ideal storm track with both sufficient cold air and ample moisture for the storm to “tap.” 
 

These are some of the major winter storms to have occurred on or near President’s Day in the Mid-Atlantic Region.

2007: This winter storm was significant not for a high amount of snow, but rather for the unusually high amount of sleet that accumulated in the Mid-Atlantic Region on February 14.  2” to 4” of sleet accumulated across much of the region that caused power outages.  Although the storm was able to draw a significant amount of moisture, there wasn’t enough cold air for a pure snow event.

2003: This was the largest storm of a snowier than average winter in the Nation’s Capital.  The snow began February 16 and 16.4” accumulated at National Airport.  That amount is tied with the December 2009 storm as the 7^th largest on record.  It was the fourth largest snowstorm at Dulles Airport where 21.7” of snow fell.  However, in Baltimore (measured at BWI Airport), this storm ranks as their largest on record when 26.8” of snow fell, narrowly beating the January 1996 storm total of 26.6” according to the National Weather Service.

1983:  One of the larger snowstorms on record occurred in the Nation’s Capital on February 10-11.  Although it was later supplanted by more recent and larger snowstorms, such as the January 1996 storm and the 2009-2010 storms, this 1983 snowfall remains among the Top Ten largest on record in both Washington, D.C., and Baltimore.  The 16.6” that fell at National made this the 6^th largest snowfall on record while the 22.8” at Dulles made this their 5^th largest snow total.  The 22.8" in Baltimore was their 3^rd highest snow total. 

1979:  Longtime Washingtonians will remember this historic storm which occurred on February 18 and 19.  It remains the third largest on record in the Nation’s Capital with 18.7” observed at National Airport.  In fact, it remains the single largest snow total on record at National Airport.  The top two snowstorms on record in Washington, D.C., occurred before National Airport opened in 1941.  16.3” fell at Dulles Airport making it their 6^th largest snowstorm on record while 20” fell in Baltimore making it their 8^th largest snow.

Incidentally on President’s Day 2015, the Mid-Atlantic Region is bracing for its largest snow of the season starting this evening.  A winter storm warning will go into effect at 6 PM and continue until noon tomorrow.  So it’s important to monitor the latest forecast developments from your favorite meteorologists such as my colleagues on the WUSA9 weather team.

Weather Quiz

Current Snow Depth in the Northeast  Source: NOAA/NWS

True or False.

With over 6 feet of snow in just the last month – and another major winter storm bearing down on Boston this weekend – this has been Boston’s snowiest winter on record.

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Answer to Weather Quiz question from February 1.

False.  A snowier than average winter does not mean the winter as a whole was colder than average.  The same way a colder than average winter doesn’t necessarily equate to a snowier than average winter.  From a meteorological perspective, the 2009-2010 winter (December 1 through February 28) featured close to normal temperatures with two of the three months slightly colder than average and one month a touch warmer than average.  What people remember most about the 2009-2010 winter in the Nation’s Capital were the two top ten snowstorms that came that season – one in December and one in early February. 

How Does Storm Track Impact Snowfall?

Snow in Chicago, IL   (February 1, 2015)

Although record snowfall in cities such as Boston and Chicago have grabbed headlines this winter, the Nation’s Capital and Mid-Atlantic Region at large have seen precious little snowfall.  That’s not to say there hasn’t been sufficient cold air in place at times this winter – such as the coldest weather of the season that’s on tap the next few days – but the storm track just hasn’t coincided with the timing of the cold air outbreaks.  The largest snowfall we’ve seen so far this winter came on January 6 when 2.4” fell at National Airport.  
  
The reason we haven’t seen more appreciable snowfall this winter has been because of a generally unfavorable storm track.  To read more, check out this story I wrote for the WUSA9 website.