February's Wet Start in the Nation's Capital

February 4 got off to an icy start in parts of the DC Metro  (Photo Courtesy: Carl Gottlieb)

February is a diverse weather month in the Nation’s Capital.  Over the last twenty years Washingtonians have had a total of 15 record highs (seven record highs and eight record high low temperatures – meaning the daytime “low” temperature remained unusually warm) with only one record low temperature.  Area residents may recall the record warmth of February 8, 2017, when high temperatures reached 74° at National Airport and 71° at Dulles Airport.

By comparison, the warmest temperature so far this month was 54° on February 1.  Some beneficial rainfall has also occurred over the last week with 1.12” on February 4 and another 0.49” at National Airport yesterday.  The 1.67” of rain Washingtonians have had over the first week of February makes this the “wettest” month in DC since November.  While the rain is good news given the moderate to severe drought conditions, the disappointment of area snow lovers dates back to last winter.  Despite the several weeks of colder than average temperatures earlier this winter, the predominant storm track hasn’t been favorable for appreciable snowfall in the DC Metro Area.  

While NOAA expects above average temperatures for the Mid-Atlantic Region over the next one to two weeks, the Climate Prediction Center still expects February as a whole to finish with below average temperatures.  So snow lovers in the DC Metro Area shouldn’t give up hope for at least one respectable snowstorm this winter.  While DC residents have had their second (2010) and fourth (2003) snowiest February’s on record relatively recently, 14 of the last 20 February’s have had below average snowfall.  Meanwhile, there have been only two February’s since 1998 where DC has had snowfall within 0.5” of average.

That helps illustrate how rare the right elements are for an appreciable snowfall in the Nation’s Capital.  But when the right ingredients come together on occasion, February has had significant snowfall.  Given the unique geography of the DC-Baltimore Metro Area, there is often a high degree of difference between snowfall totals and temperatures.  Weather measurements for Washington, D.C. are made at National Airport whose proximity to the Potomac River has a large impact on temperatures.  Taking the urban heat island effect into account, it’s no surprise that Dulles Airport typically has higher snow totals and colder winter temperatures than National.

Over the last 20 years, Dulles Airport has had a total of 23 record highs (combining record high and record high low temperatures) in February for a total similar to National Airport.  However, over the same time period Dulles has also had 18 record low temperatures (combining record low and record low high temperatures).  This rather large difference in record low February temperatures can be attributed to two primary reasons.  Besides being in a more rural area than National away from a body of water, weather records at Dulles Airport only date back to 1960 compared to the 1870s downtown.