January Comes to a Frigid Close

January 2019 has been a unique weather month in the Nation’s Capital.  After a warm start, Washingtonians experienced appreciable snowfall followed by milder than average days and a frigid conclusion to the month.  However, not all of that can be seen in the monthly averages.  Through January 30, DC’s average monthly temperature (combining daily high and low temperatures) was 1.8° above average.

Today is DC’s coldest day in more than a year, with an unofficial low temperature of 10° at National Airport.  The last time it was colder was on January 7, 2018 (8°).  Meanwhile, the temperature fell to -2° at Dulles Airport this morning for its coldest temperature since February 24, 2015 (-4°).  High temperatures are poised to remain in the upper 10s and 20s for the second time this month.  Washingtonians experienced a frigid January 21 with a high/low temperature of 24°/15°

If you add January 13’s high temperature of 32°, Washington, D.C. has had three days this month with high temperatures at or below freezing.  None of those dates occurred consecutively meaning there have been several, short-lived outbreaks of frigid air this month.  At the same time, Washingtonians have enjoyed the same number of days with highs of at least 60°.  That includes DC’s fourth warmest New Year’s Day on record with a high temperature of 64°.  It was also DC’s warmest January 1 temperature since 2005 (69° - the record high for the date).  

Following a streak of warmer than average temperatures on 10 of the first 11 days of January, DC had colder than average temperatures on 13 of the final 20 days of the month (including today).  That will produce a near average monthly average temperature when final statistics are in.  There hasn’t be any record cold this month in Washington, D.C. and the two coldest days have both been dry, so some local winter weather enthusiasts would say that was “wasted cold.”  Nevertheless, 11.5” of snow fell in the Nation’s Capital this month, making January 2019 snowier than average.  It’s also DC’s snowiest month, overall, since January 2016 (18.8”).  

January 2019 will also finish as a wetter than average month, with a total of 3.3” of rain (including liquid snow equivalent).  That makes this DC’s wettest January since 2015 (3.73”).  Having a wetter or drier than average January isn’t a strong indicator of what the rest of the year will be like.  For example, January 2016 and January 2017 were each drier than average months, overall, in what were drier than average years in the Nation’s Capital.  However, January 2018 was DC’s fourth driest on record (0.94”) and last year went on to become DC’s wettest on record.  

Similarly, January 2016 was a snowier than average month in the Nation’s Capital, but the rest of the 2015-2016 winter season saw a combined total of only 3.4” of snow in February and March (below the two month average of 7”).  Meanwhile, more snow occurred in DC last March (4.5”) then during the entire 2017-2018 winter season combined (4.3”).   

Historic Cold in Washington, D.C. ?

Photo Credit: Paul Laudicina

Almost 100 years have passed since Washington, D.C.’s largest snowstorm on record, “The Knickerbocker Storm” of January 28, 1922.  However, snow is a secondary part of the weather forecast as a blast of arctic air will arrive tomorrow evening.  My colleagues and I on the WUSA9 Weather team are watching the arrival of what is shaping up to be the coldest weather in the Nation’s Capital in more than five years.  While record lows aren’t expected downtown, areas like Dulles Airport could challenge records.

Weather records in Washington, D.C. date back to 1871.  As recently as the early 1940s when National Airport opened, the DC Metro Area was very rural.  Once you got outside of the District of Columbia, you were in the countryside.  There has been rapid development and urbanization since then which has contributed to a more pronounced urban heat island effect. There has been only one record low temperature in Washington, D.C. between December 1 and February 28 in the last 25 years.  On the other hand, less urban areas like Dulles Airport have set multiple record lows during that time span.

This week’s arctic outbreak, while relatively short-lived, will be a memorable one.  On Thursday morning Chicago, Illinois could break its record for all-time lowest temperature of -27° (that occurred on January 20, 1985).  Chicago can also set a new record for coldest “high” temperature on Wednesday.  At Chicago’s O’Hare airport, the current record for coldest “high” temperature is -11° (that occurred twice previously on January 18, 1994 and December 24, 1983).

Meanwhile, Washington, D.C. hasn’t been below 0° since January 19, 1994 (-4°).  That was also the last time Washingtonians experienced a “high” temperature of less than 10°.  Those were the last record lows in the Nation’s Capital in the month of January.  High temperatures in the Nation’s Capital on Thursday, January 31 could remain below 20°.  If that were to happen, it would be the first time since January 22, 2014 (19°).  The extreme cold will be relatively short-lived in Washington, D.C. with high temperatures expected to remain at or below freezing on only three consecutive days (Wednesday – Friday).

Record Low / Record Low High (Source: National Weather Service)

January 30

Washington, D.C., National Airport (DCA): -6° (1873) / 16° (1934)
Dulles Airport, Sterling, VA (IAD): 2° (1965) / 12° (1966)
Baltimore, MD (BWI Airport): -4° (1873) / 16° (1966)


January 31

DCA: -2° (1905) / 22° (1936)
IAD: -7° (1965) / 26° (2004, 1965)
BWI: 4° (1966, 1965) / 22° (1948)

Last time High Temperature <20°

DCA: 19° (January 22, 2014)
IAD: 19° (January 6, 2018)
BWI: 18° (January 6, 2018)

Last time High Temperature <10°

DCA: 8° (January 19, 1994)
IAD: 6° (January 19, 1994)
BWI: 5° (January 19, 1994)

Last time Low temperature </=5°

DCA: 5° (February 20, 2015)
IAD: -1° (January 7, 2018)
BWI: 1° (January 7, 2018)

Last time Low Temperature <0°

DCA: -4° (January 19, 1994)
IAD: -1° (January 7, 2018)
BWI: -1° (February 5, 1996)

Last time 3/+ days of temperatures </=32°

DCA: January 4 – 7, 2018 (4 consecutive days)
IAD: December 27, 2017 – January 7, 2018 (12 consecutive days)
BWI: December 31, 2017 – January 7, 2018 (8 consecutive days)

DC's Weather Roller Coaster !

Frigid Air on the Way to Washington, D.C.  (Source: WUSA9)

This past week has been dominated by large swings in temperature.  The final days of January will be more dramatic with much colder weather.  January 2019 has been 2.7° warmer than average through January 25.  This can largely be attributed to the very warm first nine days of the month when temperatures never fell below freezing.

But then a major shift in the weather pattern occurred, with only seven days that have been milder than average since January 10.  Washingtonians experienced their ninth largest January snow event on record on January 12 – 14 with 10.3” at National Airport.  That was DC’s largest overall snowfall since the January 2016 blizzard.  It was also more snow than during each of the last two winters.

There have been three days this month with high temperatures in the 60s, while two days had temperatures that remained at or below freezing.  On January 20, Washington, D.C. had a high temperature of 56° at 4:30 AM but temperatures dropped precipitously to a daily low of 18° at 11:59 PM after a powerful cold front came through.  DC’s high/low temperatures of 24°/15° on January 21 was its coldest day in more than a year.

While Dulles Airport in nearby Sterling, Virginia, has had below 0° temperatures in three of the last five winters, Washington, D.C., hasn’t been below zero since January 19, 1994 (-4°).  This is largely due to the fact that Dulles Airport is located in a more rural area where there is less of an urban heat island effect.  It’s also away from the moderating influence of the Potomac River. 

Next week much of the eastern United States will experience an arctic outbreak of rare intensity.  A powerful cold front will pass through the Mid-Atlantic Region on Tuesday afternoon, which is expected to produce DC’s coldest temperatures in more than five years.  The last time the Nation’s Capital had a daily high temperature of less than 20° was on January 22, 2014.  If any snow occurs with the passage of the arctic front on Tuesday night, then temperatures could be even colder on Wednesday and Thursday mornings.

Last time High Temperature of Less than 20°

Washington, D.C., National Airport (DCA): 19° (January 22, 2014)
Dulles Airport, Sterling, VA (IAD): 19° (January 6, 2018)
BWI Airport, Baltimore, Maryland: 18° (January 6, 2018)

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Last time High Temperature Less than 10°

DCA: 8° (January 19, 1994)
IAD: 6° (January 19, 1994)
BWI: 5° (January 19, 1994)

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Last time Low Temperature Less than 10°

DCA: 8° (January 7, 2018)
IAD: 9° (January 15, 2019)
BWI: 1° (January 7, 2018)

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Last time Low Temperature Below 0°

DCA: -4° (January 19, 1994)
IAD: -1° (January 7, 2018)
BWI: -1° (February 5, 1996)

What do January 2016 and January 2019 have in Common ?

It has been only three short years since the record “Blizzard of 2016.”  A total of 17.8” of snow was observed at National Airport from January 22-23, 2016.  That tied the February 2010 “Snowmageddon” storm for DC’s fourth largest on record.  To add to that, 20” – 30” snow totals were common three years ago.  By comparison, January 2017 and January 2018 saw a combined 2.6” of snow (less than half of DC’s January average of 5.6”).

Fortunately for local snow lovers, the Nation’s Capital experienced its first 10”/+ since the January 2016 storm earlier this month.  The 10.3” that fell from January 12 – 14, 2019 was DC’s ninth largest January snowstorm on record.  It also made this month only the eighth snowier than average January out of the last 20.

January 2016 and January 2019 are not only similar for having above average snowfall, but also for getting off to a milder than average start.  With the exception of the 1.4” of snow in Washington, D.C. in November 2018, the 2015/2016 and 2018/2019 winters experienced a very similar first six weeks.  December 2015 and December 2018 were both milder and wetter than average with no snow in either month.  The first measurable snowfall of the 2015-2016 winter didn’t occur until January 17.  This month’s first snowfall was the January 12 – 14 event when snowfall was reported at National Airport for 35 consecutive hours.

Despite these similarities, there is a major difference between the 2015/2016 winter and this winter.  The 2015/2016 winter season featured a very strong episode of El Nino, similar to the 1982/1983 and 1997/1998 El Nino events.  By comparison, NOAA reported “ENSO-neutral continued during December 2018…”  ENSO refers to the “El Nino Southern Oscillation” that could be in an El Nino or La Nina phase or be “neutral” without the presence of either.  

One of El Nino’s hallmarks in the United States during the winter months is an active southern branch of the jet stream.  If an area of low pressure develops along the southern branch of the jet stream along the U.S. Gulf Coast / southeastern Atlantic Coast and tracks up the East Coast concurrent to an outbreak of arctic air, then a major winter storm could ensue.  That’s what happened in January 2016 and February 1983 when DC experienced its seventh largest snowstorm (16.6”).  Meanwhile, the right ingredients never came together for a significant snow event in the Nation’s Capital during the mild and wet 1997-1998 winter season.

Winter weather enthusiasts no doubt remember the record storm from three years ago and appreciate the snow that occurred earlier this month.  Longtime Washingtonians know how rare double-digit snowfalls are (with only five such occurrences in the last 20 years).  That said, the right ingredients have to come together only once to produce a winter storm capable of making ardent snow-lovers happy.