2016 in Review

2016 Brought Unique Weather to Washington, D.C.

December will finish as another warmer and drier than average month in Washington, D.C.  Ten of the 12 months of 2016 have been warmer and drier than average in the Nation’s Capital.  That’s contributed to an annual rainfall deficit of approximately eight inches at National Airport.  This year Washingtonians have dealt with a record January snowstorm, record summer heat and ongoing drought conditions.

Last winter featured the warmest December (2015) on record in the Nation’s Capital.  The first measureable snowfall of last winter didn’t occur until relatively late in the season on January 17, 2016.  Ironically, Washington, D.C. saw its fourth largest snowstorm on record with 17.8” at National Airport less than a week later (on January 22-23).  Suburbs north and west of town saw as much as double that amount, with some isolated snow totals of more than 40”.

Despite the copious amount of snow, January 2016 still finished with slightly below average precipitation at National Airport.  Meteorologists measure the liquid equivalent of the snowfall and this snow had a relatively low water content.  That’s how January was able to finish as a slightly drier than average month.  With the exception of February and May, every month of 2016 was drier than average at National Airport.  Following the driest fall since 2001 in Washington, D.C., moderate drought conditions enveloped much of the DC Metro Region.  The rainfall deficit has grown to more than 6.5” at National Airport just since September 1. 

Although July got off to a cooler than average start – including Washington, D.C.’s coolest Independence Day since 1941 – the month still finished as being one of the hottest on record.  Washingtonians had their first instance of triple-digit heat since 2012 when the high temperature reached 100 degrees on July 25, followed by three more days of triple digit heat in August.  The combination of hot and dry conditions acerbated the previously dry conditions.  This became especially significant during the fall as temperatures remained warmer than average with no appreciable shift in the weather pattern to bring the Mid-Atlantic Region any additional rainfall.

National weather headlines in 2016 include above average rainfall in parts of the western United States early in the year, as well as Hurricane Matthew’s impacts on the southeastern United States in October.  Also, devastating flooding occurred in Ellicott City, Maryland in late July due to slow-moving thunderstorms.  Locally, the dominant weather story as the year comes to a close in the Nation’s Capital remains the continued warmer and drier than average weather.

Weather Quiz

What is the warmest New Year’s Eve temperature on record in Washington, D.C.?  Hint: The average high on December 31 in the Nation’s Capital is 44 degrees.

A.  65 F

B.  70 F

C.  75 F

D.  85 F

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Answer to Weather Quiz question from December 15.

True.  With a high temperature of only 30 degrees, December 16, 2016, was the coldest December day in Washington, D.C. in six years.

Where Does December Stand ?

NOAA's Temperature Outlook for early-January 2017

The comparison to last December can be made more effectively as this month enters its final days.  Although this month saw a significant blast of arctic air mid-month, it was relatively short-lived in the Mid-Atlantic Region.  The Nation’s Capital saw its first trace of snow of the season.  However, no measurable snow has occurred yet, which matches last winter to this point.  Washingtonians set a record last winter for latest first measurable snow on record (January 17).

December 16, 2016 was the coldest December day since 2010 and it helped keep this month’s average temperatures closer to average than it would have been otherwise.  National Weather Service data indicates that this month’s average temperature at National Airport through December 25 is 0.8 degrees warmer than average.  Although that’s a far cry from the warmest December on record last year, this month is still poised to finish as the sixth consecutive warmer than average December in Washington, D.C.  Yesterday’s high and low temperatures of 51/35 degrees in the Nation’s Capital were above the December 25 averages of 44/30, but well below last year’s balmy temperatures of 69/57 degrees.

Some very interesting weather occurred on Christmas Day this year with blizzard conditions across parts of the Upper Midwest and mixed precipitation in the northern Plains.  The warm sector of the dynamic area of low pressure also brought severe weather to parts of the Midwest – a relatively unusual occurrence in late December.  Also, multiple record highs were set in southern cities including Dallas, TX, Montgomery, AL and Tampa and Miami, FL.

Temperatures are poised to be warmer than average for much of the upcoming week, with low 60s expected tomorrow in Washington, D.C.  That would be the fourth day this month with temperatures in the 60s in the Nation’s Capital.  By the end of the week, though, my colleagues and I on the WUSA9 weather team will be tracking another push of arctic air with below normal temperatures expected Friday and Saturday.  However, NOAA expects an above average chance for warmer than average temperatures for the DC Metro Region during the first week of 2017.

There are a few rain chances this week but not enough to prevent December from being the tenth drier than average month of 2016.  Through December 25, a total of 2.37” of rain has fallen in Washington, D.C., while the month averages 3.05” of rain according to the National Weather Service.  Nevertheless, that amount is still more rain that occurred in all of October and November combined.  That’s why the latest Drought Monitor Index shows moderate drought conditions continue across a significant portion of the Mid-Atlantic Region.

Talking Tropics in December

Although the hurricane season ended several weeks ago, this is a good time to discuss some follow up points from a busier than average 2016 season.  December is poised to join July as only the second month since May that hasn’t had a named tropical storm in the Atlantic Ocean Basin.  That’s remarkable considering how relatively quiet the last few hurricane seasons have been.

The final tropical storm or hurricane to develop in 2006 was November’s Hurricane Otto.  It made landfall in Nicaragua as a Category 2 hurricane on November 24.  In a touch of irony, Otto was also the final storm in the tropical east Pacific as it was one of the rare storms to cross Central America from the Atlantic and emerge in the eastern Pacific at tropical storm intensity.  Otto was also the latest hurricane to form in the Caribbean since Martha in 1969.

In a somewhat rare occurrence, tropical storms have formed in seven months of 2016 for the highest such total since 2007.  This season also saw the first Category 5 hurricane (Matthew) in the Atlantic Ocean since Felix in 2007.  Hurricane Matthew weakened considerably to Category 1 intensity before making landfall in South Carolina in October.  Matthew showed that hurricanes don’t have to be major to have significant impacts (similar to Ike in 2008 and Irene in 2011).  2005’s Wilma remains the last major (Category 3 or higher) hurricane to make landfall in the United States.

A total of 15 tropical storms, 7 hurricanes including 3 major hurricanes developed in the Atlantic in 2016.  The first storm of the season, Alex, was a very rare January hurricane.  The next storm, Bonnie, developed in late May.  Category 3 Hurricane Gaston was the Atlantic’s first major hurricane of the year when it developed in late August.  Florida had its first landfalling hurricane (Hermine) since 2005.  Hermine was the minimal hurricane that made landfall in the Florida panhandle in early September.  The first hurricane in more than a decade to impact Florida was a key talking point until Hurricane Matthew developed in late September.

The 2013 and 2014 hurricane seasons were quieter than average in the Atlantic Ocean Basin for a variety of reasons, most notably a largely inhospitable environmental for tropical development.  A major El Nino event developed in 2015 that created more favorable conditions in the tropical east Pacific (west of Mexico) that conversely led to less ideal conditions in the tropical Atlantic.  That episode of El Nino quickly dissipated in the late winter and spring leading to more favorable conditions this hurricane season.  And the result was the busiest hurricane season in the Atlantic Ocean since 2012.