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.

National Weatherperson’s Day

February 5-6, 2010 DC Area Snow Totals  (Source: NOAA-NWS)

With February, the third and final month of meteorological winter underway, it’s a good time to see how this season compares to average so far in Washington, D.C.  While December and January were both slightly colder than average, each was considerably drier than average in Washington, D.C.  January 2018 was DC’s fourth driest January on record that helped severe drought conditions envelop the DC-Baltimore corridor.

The most recent Drought Monitor Index shows severe drought conditions exist from DC-Baltimore, with moderate drought conditions over a much larger portion of the Mid-Atlantic Region.  Fortunately for the Mid-Atlantic Region, these drought conditions have arrived outside the growing season so there is less of an impact than they would otherwise have.  Fortunately, yesterday’s 1.12” of rain at National Airport made for DC’s rainiest day since August 7, 2017 (1.47”).  There are several more prospects for rain in the DC Metro Area over the next week.

There has been a discernable lack of snow in the DC Metro Area over the last two winters.  Only 3.4” of snow occurred during the entire 2016-2017 winter season with just 3.1” so far this winter.  That’s compared to the seasonal average of 15.4” of snow in Washington, D.C.  Washingtonians haven’t seen a snowfall of 5” or more since the record-setting January 2016 snowstorm.  This lack of snow has contributed to the ongoing drought conditions in the Nation’s Capital.  

All hope isn’t lost for appreciable snowfall this winter.  Today is actually the 8^th anniversary of one of DC’s largest snowstorms on record.  Longtime Washingtonians will recall that on February 5-6, 2010, “Snowmageddon” dominated local weather headlines.  The January 2016 winter storm tied “Snowmageddon” for being the fourth largest snowstorm on record with 17.8” of snow at National Airport.  Meanwhile, considerably more fell west and north of the Nation’s Capital during both storms.  A key difference between the two storms is that widespread power outages occurred during “Snowmageddon” while very few occurred during the January 2016 event.

February 5 is also “National Weatherperson’s Day” so it would be a good idea to think of your favorite meteorologists.  Meteorologists work tirelessly to both inform and educate the public on the latest weather forecasts and climate news.  In many cases, the only access people have to a scientist is when they hear the weather report on their local news.  Although social media and smartphones make access to weather information considerably easier, it’s important to rely only on reputable sources for your weather forecasts such as my colleagues and I on the WUSA9 weather team.

February and Groundhog Day

U.S. Drought Monitor Index

This year has picked up where 2017 ended with very dry conditions in the Mid-Atlantic Region.  Severe drought conditions now exist in the DC-Baltimore corridor, following DC’s fourth driest January on record (only 0.94” of rain).  The Nation’s Capital has a rainfall deficit of 9.26” since September 1, 2017, and of nearly 4.5” just since December 1 when meteorological winter began.

The last time DC residents had significant rainfall was when 1.07” fell on November 7.  There have been a few wetter than average months here and there in the Nation’s Capital, but 24 of the last 30 months have been drier than average dating back to August 2015.  During that time, DC’s rainfall deficit has swelled to more than 17”.  That helps explain the expanding area of moderate to severe drought conditions in the Mid-Atlantic Region.

Although February is DC’s snowiest month of the year on average with 5.7”, it’s also the driest month with an average of only 2.62” of liquid precipitation (rain and melted snow).  Fourteen of the last 20 February’s have been drier than average in Washington, D.C.  That’s despite the second and fourth snowiest February’s on record in 2010 and 2003, respectively.

Average temperatures in Washington, D.C. range from a high/low of 44°/29° on February 1 to 51°/34° on February 28.  February’s warmest temperature on record in the Nation’s Capital is 84° on February 25, 1930.  DC’s coldest February temperature is -15° on February 11, 1899.  That’s also the coldest overall temperature on record in Washington, D.C.  

It’s also interesting to point out that over the last 20 years the Nation’s Capital has had a total of 15 record high February temperatures (including record high and record high low temperatures) and only one record low temperature.  Weather measurements for the Nation’s Capital are made at National Airport.  By comparison, Dulles Airport has had a total of 23 record high temperatures and 18 record low temperatures (including record lows and record low high temperatures) during that time.  That can be largely attributed to differences in local geography and the fact that weather records only go back to the 1960s at Dulles, compared to the 1870s downtown.

Since today is “Groundhog Day,” Punxsutawney Phil deserves an honorable mention.  This year marks the 25^th anniversary of the iconic film, “Groundhog Day” that helped make him an indelible part of pop culture.  Since 1887, “Phil” has seen his shadow 103 times (meaning “six more weeks of winter”), compared to no shadow only 18 times.  Although a sentimental favorite, he doesn’t have a high rate of forecasting success with an accuracy rate of less than 40%.  NOAA’s Climate Prediction Center expects a 33% chance of below normal temperatures this February with above average precipitation for the DC Metro Area.  That would an excellent way to alleviate the ongoing drought conditions.